Complex formation with monomeric α-tubulin and importin 13 fosters c-jun protein stability and is required for c-jun’s nuclear translocation and activity - Kappelmann-Fenzl, Melanie; Kuphal, Silke; Krupar, Rosemarie; Schadendorf, Dirk; Umansky, Viktor; Vardimon, Lily; Hellerbrand, Claus; Boßerhoff, Anja Katrin (Cancers, 2019)
Microtubules are highly dynamic structures, which consist of α-and β-tubulin heterodimers. They are essential for a number of cellular processes, including intracellular trafficking and mitosis. Tubulin-binding chemotherapeutics are used to treat different types of tumors, including malignant melanoma. The transcription factor c-Jun is a central driver of melanoma development and progression. Here, we identify the microtubule network as a main regulator of c-Jun activity. Monomeric α-tubulin fosters c-Jun protein stability by protein–protein interaction. In addition, this complex formation is necessary for c-Jun’s nuclear localization sequence binding to importin 13, and consequent nuclear import and activity of c-Jun. A reduction in monomeric α-tubulin levels by treatment with the chemotherapeutic paclitaxel resulted in a decline in the nuclear accumulation of c-Jun in melanoma cells in an experimental murine model and in patients’ tissues. These findings add important knowledge to the mechanism of the action of microtubule-targeting drugs and indicate the newly discovered regulation of c-Jun by the microtubule cytoskeleton as a novel therapeutic target for melanoma and potentially also other types of cancer.
CRIS-Team Scopus Importer:2019-11-29
Keywords: AP1; C-Jun; Importin; Transcription factor; Tubulin

Complex reinnervation pattern after unilateral renal denervation in rats - Rodionova, Kristina; Fiedler, Christian; Günther, Franziska; Grouzmann, Eric; Neuhuber, Winfried; Fischer, Michael; Ott, Christian; Linz, Peter; Freisinger, Wolfgang; Heinlein, Sonja; Schmidt, Stefan; Schmieder, Roland; et al. (American Journal of Physiology-Regulatory Integrative and Comparative Physiology, 2016)
Renal denervation (DNX) is a treatment for resistant arterial hypertension. Efferent sympathetic nerves regrow, but reinnervation by renal afferent nerves has only recently been shown in the renal pelvis of rats after unilateral DNX. We examined intrarenal perivascular afferent and sympathetic efferent nerves after unilateral surgical DNX. Tyrosine hydroxylase (TH), CGRP, and smooth muscle actin were identified in kidney sections from 12 Sprague-Dawley rats, to distinguish afferents, efferents, and vasculature. DNX kidneys and nondenervated kidneys were examined 1, 4, and 12 wk after DNX. Tissue levels of CGRP and norepinephrine (NE) were measured with ELISA and mass spectrometry, respectively. DNX decreased TH and CGRP labeling by 90% and 95%, respectively (P < 0.05) within 1 wk. After 12 wk TH and CGRP labeling returned to baseline with a shift toward afferent innervation (P < 0.05). Nondenervated kidneys showed a doubling of both labels within 12 wk (P < 0.05). CGRP content decreased by 72% [3.2 ± 0.3 vs. 0.9 ± 0.2 ng/gkidney; P < 0.05] and NA by 78% [1.1 ± 0.1 vs. 0.2 ± 0.1 pmol/mgkidney; P < 0.05] 1 wk after DNX. After 12 wk, CGRP, but not NE, content in DNX kidneys was fully recovered, with no changes in the nondenervated kidneys. The use of phenol in the DNX procedure did not influence this result. We found morphological reinnervation and transmitter recovery of afferents within 12 wk after DNX. Despite morphological evidence of sympathetic regrowth, NE content did not fully recover. These results suggest a long-term net surplus of afferent influence on the DNX kidney may be contributing to the blood pressure lowering effect of DNX.
EVALuna2:3840

Computational Analysis of Histamine Protonation Effects on H1R Binding - Conrad, Marcus; Horn, Anselm; Sticht, Heinrich (Molecules, 2023)
Despite numerous studies investigating histamine and its receptors, the impact of histamine protonation states on binding to the histamine H (Formula presented.) -receptor (H (Formula presented.) R) has remained elusive. Therefore, we assessed the influence of different histamine tautomers ((Formula presented.) -tautomer, (Formula presented.) -tautomer) and charge states (mono- vs. dicationic) on the interaction with the ternary histamine-H (Formula presented.) R-Gq complex. In atomistic molecular dynamics simulations, the (Formula presented.) -tautomer formed stable interactions with the receptor, while the (Formula presented.) -tautomer induced a rotation of the histamine ring by 180° and formed only weaker hydrogen bonding interactions. This suggests that the (Formula presented.) -tautomer is more relevant for stabilization of the active ternary histamine-H (Formula presented.) R-Gq complex. In addition to the two monocationic tautomers, the binding of dicationic histamine was investigated, whose interaction with the H (Formula presented.) R had been observed in a previous experimental study. Our simulations showed that the dication is less compatible with the ternary histamine-H (Formula presented.) R-Gq complex and rather induces an inactive conformation in the absence of the Gq protein. Our data thus indicate that the charge state of histamine critically affects its interactions with the H (Formula presented.) R. Ultimately these findings might have implications for the future development of new ligands that stabilize distinct H (Formula presented.) R activation states.
CRIS-Team Scopus Importer:2023-05-26
Keywords: G; GPCR; H; histamine; molecular dynamics; protonation; tautomers

Computational Characterization of the Binding Properties of the HIV1-Neutralizing Antibody PG16 and Design of PG16-Derived CDRH3 Peptides - Deubler, Manuel; Weißenborn, Lucas; Leukel, Simon; Horn, Anselm; Eichler, Jutta; Sticht, Heinrich (Biology, 2023)
PG16 is a broadly neutralizing antibody that binds to the gp120 subunit of the HIV-1 Env protein. The major interaction site is formed by the unusually long complementarity determining region (CDR) H3. The CDRH3 residue Tyr100H is known to represent a tyrosine sulfation site; however, this modification is not present in the experimental complex structure of PG16 with full-length HIV-1 Env. To investigate the role of sulfation for this complex, we modeled the sulfation of Tyr100H and compared the dynamics and energetics of the modified and unmodified complex by molecular dynamics simulations at the atomic level. Our results show that sulfation does not affect the overall conformation of CDRH3, but still enhances gp120 interactions both at the site of modification and for the neighboring residues. This stabilization affects not only protein–protein contacts, but also the interactions between PG16 and the gp120 glycan shield. Furthermore, we also investigated whether PG16-CDRH3 is a suitable template for the development of peptide mimetics. For a peptide spanning residues 93-105 of PG16, we obtained an experimental EC50 value of 3 (Formula presented.) (Formula presented.) for the binding of gp120 to the peptide. This affinity can be enhanced by almost one order of magnitude by artificial disulfide bonding between residues 99 and 100F. In contrast, any truncation results in significantly lower affinity, suggesting that the entire peptide segment is involved in gp120 recognition. Given their high affinity, it should be possible to further optimize the PG16-derived peptides as potential inhibitors of HIV invasion.
CRIS-Team Scopus Importer:2023-07-28
Keywords: antibody; antibody mimetic peptides; HIV-1; molecular dynamics; peptides; PG16

Computational decomposition reveals reshaping of the SARS‐CoV‐2–ACE2 interface among viral variants expressing the N501Y mutation - Socher, Eileen; Conrad, Marcus; Heger, Lukas; Paulsen, Friedrich; Sticht, Heinrich; Zunke, Friederike; Arnold, Philipp (Journal of Cellular Biochemistry, 2021)
Variants of concern of the SARS-CoV-2 virus with an asparagine-to-tyrosine substitution at position 501 (N501Y) in the receptor-binding domain (RBD) show enhanced infectivity compared to wild-type, resulting in an altered pandemic situation in affected areas. These SARS-Cov-2 variants comprise the two Alpha variants (B.1.1.7, United Kingdom and B.1.1.7 with the additional E484K mutation), the Beta variant (B.1.351, South Africa), and the Gamma variant (P.1, Brazil). Understanding the binding modalities between these viral variants and the host cell receptor ACE2 allows to depict changes, but also common motifs of virus–host cell interaction. The trimeric spike protein expressed at the viral surface contains the RBD that forms the molecular interface with ACE2. All the above-mentioned variants carry between one and three amino acid exchanges within the interface-forming region of the RBD, thereby altering the binding interface with ACE2. Using molecular dynamics (MD) simulations and decomposition of intermolecular contacts between the RBD and ACE2, we identified phenylalanine 486, glutamine 498, threonine 500, and tyrosine 505 as important interface-forming residues across viral variants. However, especially the N501Y exchange increased contact formation for this residue and also induced some local conformational changes. Comparing here, the in silico generated B.1.1.7 RBD–ACE2 complex with the now available experimentally solved structure reveals very similar behavior during MD simulation. We demonstrate, how computational methods can help to identify differences in conformation as well as contact formation for newly emerging viral variants. Altogether, we provide extensive data on all N501Y expressing SARS-CoV-2 variants of concern with respect to their interaction with ACE2 and how this induces reshaping of the RBD–ACE2 interface.

Conditional deletion of Cadherin 13 perturbs Golgi cells and disrupts social and cognitive behaviors - Tantra, M.; Guo, L.; Kim, J.; Zainolabidin, N.; Eulenburg, Volker; Augustine, G. J.; Chen, A. I. (Genes Brain and Behavior, 2018)
Inhibitory interneurons mediate the gating of synaptic transmission and modulate the activities of neural circuits. Disruption of the function of inhibitory networks in the forebrain is linked to impairment of social and cognitive behaviors, but the involvement of inhibitory interneurons in the cerebellum has not been assessed. We found that Cadherin 13 (Cdh13), a gene implicated in autism spectrum disorder and attention-deficit hyperactivity disorder, is specifically expressed in Golgi cells within the cerebellar cortex. To assess the function of Cdh13 and utilize the manipulation of Cdh13 expression in Golgi cells as an entry point to examine cerebellar-mediated function, we generated mice carrying Cdh13-floxed alleles and conditionally deleted Cdh13 with GlyT2::Cre mice. Loss of Cdh13 results in a decrease in the expression/localization of GAD67 and reduces spontaneous inhibitory postsynaptic current (IPSC) in cerebellar Golgi cells without disrupting spontaneous excitatory postsynaptic current (EPSC). At the behavioral level, loss of Cdh13 in the cerebellum, piriform cortex and endopiriform claustrum have no impact on gross motor coordination or general locomotor behaviors, but leads to deficits in cognitive and social abilities. Mice lacking Cdh13 exhibit reduced cognitive flexibility and loss of preference for contact region concomitant with increased reciprocal social interactions. Together, our findings show that Cdh13 is critical for inhibitory function of Golgi cells, and that GlyT2::Cre-mediated deletion of Cdh13 in non-executive centers of the brain, such as the cerebellum, may contribute to cognitive and social behavioral deficits linked to neurological disorders.
EVALuna2:35244

Confirmation of mutations inPROSCas a novel cause of vitamin B 6 -dependent epilepsy - Plecko, Barbara; Zweier, Markus; Begemann, Anais; Mathis, Deborah; Schmitt, Bernhard; Striano, Pasquale; Baethmann, Martina; Vari, Maria Stella; Beccaria, Francesca; Zara, Federico; Crowther, Lisa M.; Joset, Pascal; et al. (Journal of Medical Genetics, 2017)
Vitamin-B6-dependent epilepsies are a heterogenous group of treatable disorders due to mutations in several genes (ALDH7A1, PNPO, ALPLorALDH4A1). In neonatal seizures, defects inALDH7A1 and PNPOexplain a major fraction of cases. Very recently biallelic mutations inPROSCwere shown to be a novel cause in five families. We identified four further unrelated patients harbouring a total of six different mutations, including four novel disease mutations. Vitamin B6plasma profiles on pyridoxine did not enable the differentiation of patients withPROSCmutations. All four patients were normocephalic and had normal cranial imaging. Pyridoxine monotherapy allowed complete seizure control in one, while two patients had occasional febrile or afebrile seizures and one needed additional valproate therapy for photosensitive seizures. Two patients underwent a controlled pyridoxine withdrawal with signs of encephalopathy within a couple of days. Three had favourable outcome with normal intellectual properties at age 12.5, 15.5 and 30 years, respectively, while one child had marked developmental delay at age 27 months. The clinical and electroencephalographic phenotype in patients withPROSCmutations was indistinguishable fromALDH7A1andPNPOdeficiency. We therefore confirmPROSCas a novel gene for vitamin-B6-dependent epilepsy and delineate a non-specific plasma vitamin B6profile under pyridoxine treatment.
EVALuna2:33717

Conformational Dynamics of Herpesviral NEC Proteins in Different Oligomerization States - Diewald, Benedikt; Socher, Eileen; Söldner, Christian; Sticht, Heinrich (International Journal of Molecular Sciences, 2018)
All herpesviruses use a heterodimeric nuclear egress complex (NEC) to transport capsids out of host cell nuclei. Despite their overall similar structure, NECs may differ significantly in sequence between different viruses. Up to now, structural information is limited to isolated NEC heterodimers and to large hexagonal lattices made up of hexagonal ring-like structures (Hexagons). The present study aimed to expand the existing structural knowledge with information on the dynamics of NECs from different viruses and in different oligomerization states. For this task, comparative molecular dynamics simulations were performed of the free NEC heterodimers from three different viruses (HCMV (human cytomegalovirus), HSV-1 (herpes simplex virus 1), and PRV (pseudorabies virus)). In addition, higher oligomerization states comprising two or six NEC heterodimers were characterized for HCMV and HSV-1. The study revealed that the isolated NEC heterodimers from - (HSV-1, PRV) and -herpesviruses (HCMV) differ significantly in their dynamics, which can be attributed to a poorly conserved interface region between the NEC subdomains. These differences become smaller for higher oligomerization states, and both HCMV and HSV-1 individual Hexagons exhibit a common region of enhanced dynamics, which might be of functional relevance for the formation of curved vesicle structures or the recognition of hexameric capsid proteins.
EVALuna2:35491

Conformational stability of fibrillar amyloid-beta oligomers via protofilament pair formation - a systematic computational study - Kahler, Anna; Sticht, Heinrich; Horn, Anselm (PLoS ONE, 2013)
Amyloid-[Formula: see text] (A[Formula: see text]) oligomers play a crucial role in Alzheimer's disease due to their neurotoxic aggregation properties. Fibrillar A[Formula: see text] oligomerization can lead to protofilaments and protofilament pairs via oligomer elongation and oligomer association, respectively. Small fibrillar oligomers adopt the protofilament topology, whereas fibrils contain at least protofilament pairs. To date, the underlying growth mechanism from oligomers to the mature fibril still remains to be elucidated. Here, we performed all-atom molecular dynamics simulations in explicit solvent on single layer-like protofilaments and fibril-like protofilament pairs of different size ranging from the tetramer to the 48-mer. We found that the initial U-shaped topology per monomer is maintained over time in all oligomers. The observed deviations of protofilaments from the starting structure increase significantly with size due to the twisting of the in-register parallel [Formula: see text]-sheets. This twist causes long protofilaments to be unstable and leads to a breakage. Protofilament pairs, which are stabilized by a hydrophobic interface, exhibit more fibril-like properties such as the overall structure and the twist angle. Thus, they can act as stable conformational templates for further fibril growth. Key properties like the twist angle, shape complementarity, and energetics show a size-dependent behavior so that small oligomers favor the protofilament topology, whereas large oligomers favor the protofilament pair topology. The region for this conformational transition is at the size of approximately twelve A[Formula: see text] monomers. From that, we propose the following growth mechanism from A[Formula: see text] oligomers to fibrils: (1) elongation of short protofilaments; (2) breakage of large protofilaments; (3) formation of short protofilament pairs; and (4) elongation of protofilament pairs.
EVALuna2:26277

Confounding influence of tamoxifen in mouse models of Cre recombinase-induced gene activity or modulation - Hammad, Seddik; Othman, Amnah; Meyer, Christoph; Telfah, Ahmad; Lambert, Joerg; Dewidar, Bedair; Werle, Julia; Nwosu, Zeribe Chike; Mahli, Abdo; Dormann, Christof; Gao, Yan; Gould, Kerry; et al. (Archives of Toxicology, 2018)
Tamoxifen (TAM) is commonly used for cell type specific Cre recombinase-induced gene inactivation and in cell fate tracing studies. Inducing a gene knockout by TAM and using non-TAM exposed mice as controls lead to a situation where differences are interpreted as consequences of the gene knockout but in reality result from TAM-induced changes in hepatic metabolism. The degree to which TAM may compromise the interpretation of animal experiments with inducible gene expression still has to be elucidated. Here, we report that TAM strongly attenuates CCl4-induced hepatotoxicity in male C57Bl/6N mice, even after a 10 days TAM exposure-free period. TAM decreased (p < 0.0001) the necrosis index and the level of aspartate- and alanine transaminases in CCl4-treated compared to vehicle-exposed mice. TAM pretreatment also led to the downregulation of CYP2E1 (p = 0.0045) in mouse liver tissue, and lowered its activity in CYP2E1 expressing HepG2 cell line. Furthermore, TAM increased the level of the antioxidant ascorbate, catalase, SOD2, and methionine, as well as phase II metabolizing enzymes GSTM1 and UGT1A1 in CCl4-treated livers. Finally, we found that TAM increased the presence of resident macrophages and recruitment of immune cells in necrotic areas of the livers as indicated by F4/80 and CD45 staining. In conclusion, we reveal that TAM increases liver resistance to CCl4-induced toxicity. This finding is of high relevance for studies using the tamoxifen-inducible expression system particularly if this system is used in combination with hepatotoxic compounds such as CCl4.
EVALuna2:35810

Conservation and variation of structure and function in a newly identified GCM homolog from chicken - Wegner, Michael; Hashemolhosseini, Said; et al. (Journal of Molecular Biology, 2004)
Glial cell missing (GCM) proteins constitute a small family of transcription factors with two members each described in Drosophila and several mammalian species. Here, we report the identification of a GCM homolog from chicken. Although the exon-intron structure is well conserved between chicken GCM and other family members, sequence similarity is largely restricted to the DNA-binding GCM-domain (residues 24-176). In accord with the high degree of sequence conservation within the GCM-domain, the chicken GCM protein has a DNA-binding specificity similar to that of other GCM proteins. Like other GCM proteins, it is located to the nucleus and can act as a transcriptional activator despite the strong divergence in sequences outside the GCM-domain. The chicken GCM protein contains two transactivation domains with cell-specific function, one immediately following the DNA-binding domain, the other at its extreme carboxy terminus. Intriguingly, chicken GCM is expressed only transiently during embryogenesis and is restricted exclusively to extraembryonic tissues where it was detected in close vicinity to embryonic blood vessels. Taking the extraembryonic expression of chicken GCM and mammalian GCMa into account, it is tempting to speculate that a conserved extraembryonic function exists for GCM proteins in birds and mammals. © 2003 Elsevier Ltd. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2004.med.IB.LPCIPDBI.conser
Keywords: Gcm-1; GCMa; Glial cells missing; Placenta

Contribution of the ?8 integrin chain to the expression of extracellular matrix components - Volkert, Gudrun; Jahn, Angelika; Dinkel, Christina; Fahlbusch, Fabian; Zuern, Christina; Hilgers, Karl Friedrich; Rascher, Wolfgang; Marek, Ines; Hartner, Andrea (Cell Communication and Adhesion, 2014)
In the kidney, the ?8 integrin chain (itga8) is expressed in mesenchymal cells and is upregulated in fibrotic disease. We hypothesized that itga8 mediates a profibrotic phenotype of renal cells by promoting extracellular matrix and cytokine expression. Genetic itga8 deficiency caused complex changes in matrix expression patterns in mesangial and smooth-muscle cells, with the only concordant effect in both cell types being a reduction of collagen III expression. Silencing of itga8 with siRNA led to a decline of matrix turnover with repression of matrix metalloproteinases and reduction of matrix production. In contrast, de novo expression of itga8 in tubular epithelial cells resulted in reduced collagen synthesis. Overexpression of itga8 in fibroblasts did not change the expression of matrix molecules or regulators of matrix turnover. Thus, the influence of itga8 on the expression of matrix components was not uniform and celltype dependent. Itga8 seems unlikely to exert overall profibrotic effects in renal cells.
EVALuna2:3701

Cooperative binding of Sox10 to DNA: requirements and consequences - Wegner, Michael; et al. (Nucleic Acids Research, 2002)
The high-mobility-group (HMG) domain containing transcription factor Sox10 is an important regulator of various processes including the development of neural crest cells and glial cells. Target gene promoters contain multiple Sox10-binding sites, which either support monomeric or cooperative, dimeric binding. The latter is unusual for Sox proteins and might contribute to functional specificity of Sox10. We find that specific amino acid residues in a conserved region immediately preceding the HMG domain of Sox10 are required for cooperative binding. These residues cooperate with the HMG domain during dimeric binding in a manner dependent on specific determinants within the first two α-helices of the HMG domain. Cooperativity of DNA binding is surprisingly refractory to changes in the overall conformation of the DNA-bound dimer. Whereas maintenance of cooperativity is essential for full activation of the promoter of the myelin protein zero target gene, dimer-dependent conformational changes such as the exact bending angle introduced into the promoter appear to be less important, shedding new light on the architectural function of Sox proteins.
UnivIS-Import:2015-03-09:Pub.2002.med.IB.LPCIPDBI.cooper_1

Cooperative function of POU proteins and SOX proteins in glial cells - Sock, Elisabeth; Wegner, Michael; et al. (Journal of Biological Chemistry, 1998)
Glial cells of the oligodendrocyte lineage express several highly related POU proteins including Tst-1/Oct6/SCIP and Brn-1. Tst-1/Oct6/SCIP, but not Brn-1 efficiently cooperated with Sox10, the only SRY box protein so far identified in oligodendrocytes. Here we show that, in addition to Sox10, cells of the oligodendrocyte lineage contain significant amounts of the related SRY box proteins Sox4 and Sox11. During development, Sox11 was strongly expressed in the central nervous system. It was first detected in neural precursors throughout the neuroepithelium. During later stages of neural development, Sox11 was additionally expressed in areas of the brain in which neurons undergo differentiation. In agreement with its expression in neural precursors, Sox11 levels in cells of the oligodendrocyte lineage were high in precursors and down-regulated during terminal differentiation. Outside the nervous system, expression of Sox11 was also detected in the developing limbs, face, and kidneys. Structure function analysis revealed that Sox11 has a strong intrinsic transactivation capacity which is mediated by a transactivation domain in its carboxyl-terminal part. In addition, Sox11 efficiently synergized with Bru-1. Synergy was dependent on binding of both proteins to adjacent DNA elements, and required the presence of the respective transactivation domain in each protein. Our data suggest the existence of a specific code in which POU proteins require specific Sox proteins to exhibit cooperative effects in glial cells.
UnivIS-Import:2015-03-05:Pub.1998.med.IB.LPCIPDBI.cooper

Coordination of Schwann cell myelination and node formation at the transcriptional level - Fröb, Franziska; Wegner, Michael (Neural Regeneration Research, 2022)
CRIS-Team Scopus Importer:2021-12-24

Copy number variation of two separate regulatory regions upstream of SOX9 causes isolated 46,XY or 46,XX disorder of sex development - Kim, Gwang-Jin; Sock, Elisabeth; Buchberger, Astrid; Just, Walter; Denzer, Friederike; Hoepffner, Wolfgang; German, James; Cole, Trevor; Mann, Jillian; Seguin, John H.; Zipf, William; Costigan, Colm; et al. (Journal of Medical Genetics, 2015)
SOX9 mutations cause the skeletal malformation syndrome campomelic dysplasia in combination with XY sex reversal. Studies in mice indicate that SOX9 acts as a testis-inducing transcription factor downstream of SRY, triggering Sertoli cell and testis differentiation. An SRY-dependent testis-specific enhancer for Sox9 has been identified only in mice. A previous study has implicated copy number variations (CNVs) of a 78 kb region 517-595 kb upstream of SOX9 in the aetiology of both 46,XY and 46,XX disorders of sex development (DSD). We wanted to better define this region for both disorders.By CNV analysis, we identified SOX9 upstream duplications in three cases of SRY-negative 46,XX DSD, which together with previously reported duplications define a 68 kb region, 516-584 kb upstream of SOX9, designated XXSR (XX sex reversal region). More importantly, we identified heterozygous deletions in four families with SRY-positive 46,XY DSD without skeletal phenotype, which define a 32.5 kb interval 607.1-639.6 kb upstream of SOX9, designated XY sex reversal region (XYSR). To localise the suspected testis-specific enhancer, XYSR subfragments were tested in cell transfection and transgenic experiments. While transgenic experiments remained inconclusive, a 1.9 kb SRY-responsive subfragment drove expression specifically in Sertoli-like cells.Our results indicate that isolated 46,XY and 46,XX DSD can be assigned to two separate regulatory regions, XYSR and XXSR, far upstream of SOX9. The 1.9 kb SRY-responsive subfragment from the XYSR might constitute the core of the Sertoli-cell enhancer of human SOX9, representing the so far missing link in the genetic cascade of male sex determination.
EVALuna2:4981

Correction to: De novo variants in SNAP25 cause an early-onset developmental and epileptic encephalopathy (Genetics in Medicine, (2020), 10.1038/s41436-020-01020-w) - Klöckner, Chiara; Sticht, Heinrich; Zacher, Pia; Popp, Bernt; Babcock, Holly E.; Bakker, Dewi P.; Barwick, Katy; Bonfert, Michaela V.; Bönnemann, Carsten G.; Brilstra, Eva H.; Chung, Wendy K.; Clarke, Angus J.; et al. (Genetics in Medicine, 2021)
Unfortunately, in the first sentence in the abstract, a spelling mistake was introduced during the production process after our proofreading. The wording was changed from “aims” to “aimsed.” Heather M. McLaughlin was not listed among the authors. The original article has been corrected.
CRIS-Team Scopus Importer:2021-03-19

Correction to: The recurrent missense mutation p.(Arg367Trp) in YARS1 causes a distinct neurodevelopmental phenotype (Journal of Molecular Medicine, (2021), 10.1007/s00109-021-02124-9) - Averdunk, Luisa; Sticht, Heinrich; Surowy, Harald; Luedecke, Hermann-Josef; Koch-Hogrebe, Margarete; Alsaif, Hessa S.; Kahrizi, Kimia; Alzaidan, Hamad; Alawam, Bashayer S.; Tohary, Mohamed; Kraus, Cornelia; Endele, Sabine; et al. (Journal of Molecular Medicine, 2021)
In the published original paper, Fig. 1 is incomplete. Only Fig. 1a is shown. This erratum corrects Fig. 1 and adds the missing panel 1 b-f to the article.
CRIS-Team Scopus Importer:2021-10-29

Crazy Little Thing Called Sox-New Insights in Oligodendroglial Sox Protein Function - Wittstatt, Jan; Reiprich, Simone; Küspert, Melanie (International Journal of Molecular Sciences, 2019)
In the central nervous system, oligodendrocytes wrap axons with myelin sheaths, which is essential for rapid transfer of electric signals and their trophic support. In oligodendroglia, transcription factors of the Sox protein family are pivotal regulators of a variety of developmental processes. These include specification, proliferation, and migration of oligodendrocyte precursor cells as well as terminal differentiation to mature myelinating oligodendrocytes. Sox proteins are further affected in demyelinating diseases and are involved in remyelination following damage of the central nervous system. Here we summarize and discuss latest findings on transcriptional regulation of Sox proteins, their function, target genes, and interaction with other transcription factors and chromatin remodelers in oligodendroglia with physiological and pathophysiological relevance.
CRIS-Team Scopus Importer:2019-06-21
Keywords: glia; myelin; oligodendrocyte; Sox protein; transcription factor

CREB in adult neurogenesis–master and partner in the development of adult-born neurons? - Merz, Katharina; Herold, Sabine; Lie, Dieter Chichung (European Journal of Neuroscience, 2011)
The generation of new neurons in the adult brain is modulated by complex stimuli and a broad range of extrinsic signals. It remains a mystery how stem cells and their progeny integrate this wealth of regulatory input to generate a precise number of neurons that matches the physiological needs of the olfactory and hippocampal network. cAMP response element binding protein (CREB)-dependent signalling is controlling essential developmental steps in adult neurogenesis, i.e. survival, maturation and integration of new neurons. Here, we summarize the current knowledge on the function of CREB in adult neurogenesis and discuss the potential of CREB to integrate complex stimuli and to translate these into precise developmental processes in adult neurogenesis. The complex modulation of CREB-signalling may allow the adult neurogenic system to respond to stimuli in a fine-tuned rather than in an on-off fashion.
EVALuna2:26343

CREB signalling regulates early survival, neuronal gene expression and morphological development in adult subventricular zone neurogenesis - Herold, S.; Jagasia, R.; Merz, K.; Wassmer, K.; Lie, Dieter Chichung (Molecular and Cellular Neuroscience, 2011)
Neural stem cells in the subventricular zone (SVZ) of the lateral ventricles give rise to new interneurons of the olfactory bulb (OB) throughout life. SVZ/OB neurogenesis is influenced by olfactory network activity, which modulates the survival of new neurons during their integration into the OB network. Previous work suggested that such activity-dependent survival is regulated via the CREB signalling pathway. Curiously, CREB signalling is already active during the early developmental stages of adult SVZ/OB neurogenesis. To investigate the role of cell autonomous CREB signalling during early stages of adult SVZ/OB neurogenesis, we ablated CREB-pathway activity in the SVZ/OB neurogenic lineage using a retroviral strategy. Surprisingly, loss of CREB signalling resulted in increased cell death and loss of expression of the neurogenic transcription factor Pax 6, and of a subset of neuronal proteins in migrating neurons of the RMS. Moreover, post-migratory neurons in the OB displayed impaired dendritic development. These results demonstrate an essential role for CREB signalling in maturation of newborn neurons in the OB and uncover a novel role for CREB signalling in the survival and maintenance of neuronal gene expression during the early stages of SVZ/OB neurogenesis.
EVALuna2:26346

CRIP1a inhibits endocytosis of G-protein coupled receptors activated by endocannabinoids and glutamate by a common molecular mechanism - Mascia, Fabrizio; Klotz, Lisa; Lerch, Judith; Ahmed, Mostafa H.; Zhang, Yan; Enz, Ralf (Journal of Neurochemistry, 2017)
The excitability of the central nervous system depends largely on the surface density of neurotransmitter receptors. The endocannabinoid receptor 1 (CB1 R) and the metabotropic glutamate receptor mGlu8 R are expressed pre-synaptically where they reduce glutamate release into the synaptic cleft. Recently, the CB1 R interacting protein cannabinoid receptor interacting protein 1a (CRIP1a) was identified and characterized to regulate CB1 R activity in neurons. However, underlying molecular mechanisms are largely unknown. Here, we identified a common mechanism used by CRIP1a to regulate the cell surface density of two different types of G-protein coupled receptors, CB1 R and mGlu8a R. Five amino acids within the CB1 R C-terminus were required and sufficient to reduce constitutive CB1 R endocytosis by about 72% in the presence of CRIP1a. Interestingly, a similar sequence is present in mGlu8a R and consistently, endocytosis of mGlu8a R depended on CRIP1a, as well. Docking analysis and molecular dynamics simulations identified a conserved serine in CB1 R (S468) and mGlu8a R (S894) that forms a hydrogen bond with the peptide backbone of CRIP1a at position R82. In contrast to mGlu8a R, the closely related mGlu8b R splice-variant carries a lysine (K894) at this position, and indeed, mGlu8b R endocytosis was not affected by CRIP1a. Chimeric constructs between CB1 R, mGlu8a R, and mGlu8b R underline the role of the identified five CRIP1a sensitive amino acids. In summary, we suggest that CRIP1a negatively regulates endocytosis of two different G-protein coupled receptor types, CB1 R and mGlu8a R.
EVALuna2:4771

CRISPR/Cas9-mediated generation of hESC lines with homozygote and heterozygote p.R331W mutation in CTBP1 to model HADDTS syndrome - Akdas, Enes Yagiz; Turan, Sören; Guhathakurta, Debarpan; Ekici, Arif Bülent; Salar, Seda; Lie, Dieter Chichung; Winner, Beate; Fejtová, Anna (Stem Cell Research, 2023)
C-terminal Binding Protein 1 (CTBP1) is a ubiquitously expressed transcriptional co-repressor and membrane trafficking regulator. A recurrent de novo c.991C>T mutation in CTBP1 leads to expression of p.R331W CTBP1 and causes hypotonia, ataxia, developmental delay, and tooth enamel defects syndrome (HADDTS), a rare early onset neurodevelopmental disorder. We generated hESCs lines with heterozygote and homozygote c.991C>T in CTBP1 using CRISPR/Cas9 genome editing and validated them for genetic integrity, off-target mutations, and pluripotency. They will be useful for investigation of HADDTS pathophysiology and for screening for potential therapeutics.
CRIS-Team Scopus Importer:2023-01-20

CRISPR/Cas9-mediated generation of hESC lines with homozygote and heterozygote p.R331W mutation in CTBP1 to model HADDTS syndrome. - Winner, Beate; Akdas, Enes Yagiz; Turan, Sören; Guhathakurta, Debarpan; Ekici, Arif Bülent; Salar, Seda; Lie, Dieter Chichung; Fejtová, Anna (Stem Cell Research, 2023)
C-terminal Binding Protein 1 (CTBP1) is a ubiquitously expressed transcriptional co-repressor and membrane trafficking regulator. A recurrent de novo c.991C>T mutation in CTBP1 leads to expression of p.R331W CTBP1 and causes hypotonia, ataxia, developmental delay, and tooth enamel defects syndrome (HADDTS), a rare early onset neurodevelopmental disorder. We generated hESCs lines with heterozygote and homozygote c.991C>T in CTBP1 using CRISPR/Cas9 genome editing and validated them for genetic integrity, off-target mutations, and pluripotency. They will be useful for investigation of HADDTS pathophysiology and for screening for potential therapeutics.

CRISPR/Cas9 mediated generation of human ARID1B heterozygous knockout hESC lines to model Coffin-Siris syndrome - Börstler, Tom; Wend, Holger; Krumbiegel, Mandy; Kavyanifar, Atria; Wiesmann da Silva Reis, André; Lie, Dieter Chichung; Winner, Beate; Turan, Sören (Stem Cell Research, 2020)
ARID1B haploinsufficiency induced by missense or nonsense mutations of ARID1B is a cause of Coffin-Siris syndrome (CSS), a neurodevelopmental disorder associated with intellectual disability. At present, no appropriate human stem cell model for ARID1B-associated CSS has been reported. Here, we describe the generation and validation of ARID1B(+/-) hESCs by introducing out of frame deletions into exon 5 or 6 of ARID1B with CRISPR/Cas9 genome editing. These ARID1B(+/-) hESC lines allow to study the pathophysiology of ARID1B-associated CSS in 2D and 3D models of human neurodevelopment.

CRISPR/Cas9 mediated generation of human ARID1B heterozygous knockout hESC lines to model Coffin-Siris syndrome - Börstler, Tom; Wend, Holger; Krumbiegel, Mandy; Kavyanifar, Atria; Reis, André; Lie, Dieter Chichung; Winner, Beate; Turan, Sören (Stem Cell Research, 2020)
ARID1B haploinsufficiency induced by missense or nonsense mutations of ARID1B is a cause of Coffin-Siris syndrome (CSS), a neurodevelopmental disorder associated with intellectual disability. At present, no appropriate human stem cell model for ARID1B-associated CSS has been reported. Here, we describe the generation and validation of ARID1B+/- hESCs by introducing out of frame deletions into exon 5 or 6 of ARID1B with CRISPR/Cas9 genome editing. These ARID1B+/- hESC lines allow to study the pathophysiology of ARID1B-associated CSS in 2D and 3D models of human neurodevelopment.
CRIS-Team Scopus Importer:2020-07-24

CRISPR/Cas9 mediated generation of human ARID1B heterozygous knockout hESC lines to model Coffin-Siris syndrome. - Turan, Soeren; Winner, Beate; Winner, Beate; Krumbiegel, Mandy; Wiesmann da Silva Reis, André; Lie, Dieter Chichung; Börstler, Tom; Wend, Holger; Krumbiegel, Mandy; Kavyanifar, Atria; Reis, Andre; Lie, Dieter Chichung (Stem Cell Research, 2020)
ARID1B haploinsufficiency induced by missense or nonsense mutations of ARID1B is a cause of Coffin-Siris syndrome (CSS), a neurodevelopmental disorder associated with intellectual disability. At present, no appropriate human stem cell model for ARID1B-associated CSS has been reported. Here, we describe the generation and validation of ARID1B+/- hESCs by introducing out of frame deletions into exon 5 or 6 of ARID1B with CRISPR/Cas9 genome editing. These ARID1B+/- hESC lines allow to study the pathophysiology of ARID1B-associated CSS in 2D and 3D models of human neurodevelopment.

Crybb2 coding for ?B2-crystallin affects sensorimotor gating and hippocampal function - Sun, Minxuan; Hoelter, Sabine M.; Stepan, Jens; Garrett, Lillian; Genius, Just; Kremmer, Elisabeth; De Angelis, Martin Hrabe; Wurst, Wolfgang; Lie, Dieter Chichung; Bally-Cuif, Laure; Eder, Matthias; Rujescu, Dan; et al. (Mammalian Genome, 2013)
?B2-crystallin (gene symbol: Crybb2/CRYBB2) was first described as a structural protein of the ocular lens. This gene, however, is also expressed in several regions of the mammalian brain, although its function in this organ remains entirely unknown. To unravel some aspects of its function in the brain, we combined behavioral, neuroanatomical, and physiological analyses in a novel Crybb2 mouse mutant, O377. Behavioral tests with male O377 mutants revealed altered sensorimotor gating, suggesting modified neuronal functions. Since these mouse mutants also displayed reduced hippocampal size, we concentrated further investigations on the hippocampus. Free intracellular Ca(2+) levels were increased and apoptosis was enhanced in the hippocampus of O377 mutants. Moreover, the expression of the gene encoding calpain 3 (gene symbol Capn3) was elevated and the expression of genes coding for the NMDA receptor subunits was downregulated. Additionally, the number of parvalbumin-positive interneurons was decreased in the hippocampus but not in the cortex of the mutants. High-speed voltage-sensitive dye imaging demonstrated an increased translation of input-to-output neuronal activity in the dentate gyrus of this Crybb2 mutant. These results point to an important function of ?B2-crystallin in the hippocampal network. They indicate pleiotropic effects of mutations in the Crybb2 gene, which previously had been considered to be specific to the ocular lens. Moreover, our results are the first to demonstrate that ?B2-crystallin has a role in hippocampal function and behavioral phenotypes. This model can now be further explored by future experiments.
EVALuna2:26318

Crystal structure of cytomegalovirus IE1 protein reveals targeting of TRIM family member PML via coiled-coil interactions - Scherer, Myriam; Klingl, Stefan; Sevvana, Madhumati; Otto, Victoria; Schilling, Eva-Maria; Stump, Joachim; Müller, Regina; Reuter, Nina; Sticht, Heinrich; Muller, Yves; Stamminger, Thomas (PLoS Pathogens, 2014)
PML nuclear bodies (PML-NBs) are enigmatic structures of the cell nucleus that act as key mediators of intrinsic immunity against viral pathogens. PML itself is a member of the E3-ligase TRIM family of proteins that regulates a variety of innate immune signaling pathways. Consequently, viruses have evolved effector proteins to modify PML-NBs; however, little is known concerning structure-function relationships of viral antagonists. The herpesvirus human cytomegalovirus (HCMV) expresses the abundant immediate-early protein IE1 that colocalizes with PML-NBs and induces their dispersal, which correlates with the antagonization of NB-mediated intrinsic immunity. Here, we delineate the molecular basis for this antagonization by presenting the first crystal structure for the evolutionary conserved primate cytomegalovirus IE1 proteins. We show that IE1 consists of a globular core (IE1CORE) flanked by intrinsically disordered regions. The 2.3 Å crystal structure of IE1CORE displays an all ?-helical, femur-shaped fold, which lacks overall fold similarity with known protein structures, but shares secondary structure features recently observed in the coiled-coil domain of TRIM proteins. Yeast two-hybrid and coimmunoprecipitation experiments demonstrate that IE1CORE binds efficiently to the TRIM family member PML, and is able to induce PML deSUMOylation. Intriguingly, this results in the release of NB-associated proteins into the nucleoplasm, but not of PML itself. Importantly, we show that PML deSUMOylation by IE1CORE is sufficient to antagonize PML-NB-instituted intrinsic immunity. Moreover, co-immunoprecipitation experiments demonstrate that IE1CORE binds via the coiled-coil domain to PML and also interacts with TRIM5? We propose that IE1CORE sequesters PML and possibly other TRIM family members via structural mimicry using an extended binding surface formed by the coiled-coil region. This mode of interaction might render the antagonizing activity less susceptible to mutational escape.
EVALuna2:8238

Crystal Structure of the Extracellular Domain of the Human Dendritic Cell Surface Marker CD83 - Heilingloh, Christiane; Klingl, Stefan; Egerer-Sieber, Claudia; Schmid, Benedikt; Weiler, Sigrid; Mühl-Zürbes, Petra; Hofmann, Jörg; Stump, Joachim; Sticht, Heinrich; Kummer, Mirko; Steinkasserer, Alexander; Muller, Yves (Journal of Molecular Biology, 2017)
Keywords: homotypic interactions; immune co-stimulation and -suppression; structure–function relationships; V-set Ig-domain; X-ray crystallography

Crystal structure of the human cytomegalovirus pUL50-pUL53 core nuclear egress complex provides insight into a unique assembly scaffold for virus-host protein interactions - Walzer, Sascha; Egerer-Sieber, Claudia; Sticht, Heinrich; Sevvana, Madhumati; Hohl, Katharina; Milbradt, Jens; Muller, Yves; Marschall, Manfred (Journal of Biological Chemistry, 2015)
Nuclear replication of cytomegalovirus relies on elaborate mechanisms of nucleocytoplasmic egress of viral particles. Thus, the role of two essential and conserved viral nuclear egress proteins, pUL50 and pUL53, is pivotal. pUL50 and pUL53 heterodimerize and form a core nuclear egress complex (NEC), which is anchored to the inner nuclear membrane and provides a scaffold for the assembly of a multimeric viral-cellular NEC. Here, we report the crystal structure of the pUL50-pUL53 heterodimer (amino acids 1-175 and 50-292, respectively) at 2.44 Å resolution. Both proteins adopt a globular fold with mixed α and β secondary structure elements. pUL53-specific features include a zinc-binding site and a hook-like N-terminal extension, the latter representing a hallmark element of the pUL50-pUL53 interaction. The hook-like extension (amino acids 59-87) embraces pUL50 and contributes 1510 Å to the total interface area (1880Å). The pUL50 structure overall resembles the recently published NMR structure of the murine cytomegalovirus homolog pM50 but reveals a considerable repositioning of the very C-terminal α-helix of pUL50 upon pUL53 binding. pUL53 shows structural resemblance with the GHKL domain of bacterial sensory histidine kinases. A close examination of the crystal structure indicates partial assembly of pUL50-pUL53 heterodimers to hexameric ring-like structures possibly providing additional scaffolding opportunities for NEC. In combination, the structural information on pUL50-pUL53 considerably improves our understanding of the mechanism of HCMV nuclear egress. It may also accelerate the validation of the NEC as a unique target for developing a novel type of antiviral drug and improved options of broad-spectrum antiherpesviral therapy.

CTCF-mediated chromatin looping in EGR2 regulation and SUZ12 recruitment critical for peripheral myelination and repair - Wang, Jincheng; Wang, Jiajia; Yang, Lijun; Zhao, Chuntao; Wu, Laiman Natalie; Xu, Lingli; Zhang, Feng; Weng, Qinjie; Wegner, Michael; Lu, Q. Richard (Nature Communications, 2020)
Chromatin organization is critical for cell growth, differentiation, and disease development, however, its functions in peripheral myelination and myelin repair remain elusive. In this report, we demonstrate that the CCCTC-binding factor (CTCF), a crucial chromatin organizer, is essential for Schwann cell myelination and myelin regeneration after nerve injury. Inhibition of CTCF or its deletion blocks Schwann cell differentiation at the pro-myelinating stage, whereas overexpression of CTCF promotes the myelination program. We find that CTCF establishes chromatin interaction loops between enhancer and promoter regulatory elements and promotes expression of a key pro-myelinogenic factor EGR2. In addition, CTCF interacts with SUZ12, a component of polycomb-repressive-complex 2 (PRC2), to repress the transcriptional program associated with negative regulation of Schwann cell maturation. Together, our findings reveal a dual role of CTCF-dependent chromatin organization in promoting myelinogenic programs and recruiting chromatin-repressive complexes to block Schwann cell differentiation inhibitors to control peripheral myelination and repair.
CRIS-Team Scopus Importer:2020-08-28

CTCF variants in 39 individuals with a variable neurodevelopmental disorder broaden the mutational and clinical spectrum - Konrad, Enrico; Nardini, Niels; Caliebe, Almuth; Nagel, Inga; Young, Dana; Horvath, Gabriella; Santoro, Stephanie L.; Shuss, Christine; Ziegler, Alban; Bonneau, Dominique; Kempers, Marlies; Pfundt, Rolph; et al. (Genetics in Medicine, 2019)
Purpose: Pathogenic variants in the chromatin organizer CTCF were previously reported in seven individuals with a neurodevelopmental disorder (NDD). Methods: Through international collaboration we collected data from 39 subjects with variants in CTCF. We performed transcriptome analysis on RNA from blood samples and utilized Drosophila melanogaster to investigate the impact of Ctcf dosage alteration on nervous system development and function. Results: The individuals in our cohort carried 2 deletions, 8 likely gene-disruptive, 2 splice-site, and 20 different missense variants, most of them de novo. Two cases were familial. The associated phenotype was of variable severity extending from mild developmental delay or normal IQ to severe intellectual disability. Feeding difficulties and behavioral abnormalities were common, and variable other findings including growth restriction and cardiac defects were observed. RNA-sequencing in five individuals identified 3828 deregulated genes enriched for known NDD genes and biological processes such as transcriptional regulation. Ctcf dosage alteration in Drosophila resulted in impaired gross neurological functioning and learning and memory deficits. Conclusion: We significantly broaden the mutational and clinical spectrum of CTCF-associated NDDs. Our data shed light onto the functional role of CTCF by identifying deregulated genes and show that Ctcf alterations result in nervous system defects in Drosophila.
CRIS-Team Scopus Importer:2019-07-09
Keywords: chromatin organization; CTCF; Drosophila melanogaster; intellectual disability; neurodevelopmental disorders

Cyclins B1, T1, and H differ in their molecular mode of interaction with cytomegalovirus protein kinase pUL97 - Steingruber, Mirjam; Keller, Lena; Socher, Eileen; Ferre, Sabrina; Hesse, Anne-Marie; Coute, Yohann; Hahn, Friedrich; Buescher, Nicole; Plachter, Bodo; Sticht, Heinrich; Marschall, Manfred (Journal of Biological Chemistry, 2019)
Human cytomegalovirus (HCMV) is a common -herpesvirus causing life-long latent infections. HCMV replication interferes with cell cycle regulation in host cells because the HCMV-encoded cyclin-dependent kinase (CDK) ortholog pUL97 extensively phosphorylates the checkpoint regulator retinoblastoma protein. pUL97 also interacts with cyclins B1, T1, and H, and recent findings have strongly suggested that these interactions influence pUL97 substrate recognition. Interestingly, here we detected profound mechanistic differences among these pUL97– cyclin interactions. Our study revealed the following. (i) pUL97 interacts with cyclins B1 and H in a manner dependent on pUL97 activity and HCMV-specific cyclin modulation, respectively. (ii) The phosphorylated state of both proteins is an important determinant of the pUL97–cyclin B1 interaction. (iii) Activated phospho-Thr-315 cyclin H is up-regulated during HCMV replication. (iv) Thr-315 phosphorylation is independent of intracellular pUL97 or CDK7 activity. (v) pUL97-mediated in vitro phosphorylation is detectable for cyclin B1 but not H. (vi) Mutual transphosphorylation between pUL97 and CDK7 is not detectable, and an MS-based phosphosite analysis indicated that pUL97 might unexpectedly not be phosphorylated in its T-loop. (vii) The binary complexes pUL97– cyclin H and CDK7– cyclin H as well as the ternary complex pUL97– cyclin-H–CDK7 are detectable in an assembly-based CoIP approach. (viii) pUL97 self-interaction can be bridged by the transcriptional cyclins T1 or H but not by the classical cell cycle–regulating B1 cyclin. Combined, our findings unravel a number of cyclin type–specific differences in pUL97 interactions and suggest a multifaceted regulatory impact of cyclins on HCMV replication.
CRIS-Team Scopus Importer:2019-05-03

CYLD - A potential Mediator of tissue-specific Melanoma Metastasis - Schott, Mandy; de Jel, Miriam Martha; Boßerhoff, Anja Katrin; Kuphal, Silke (2018)
EVALuna2:203600

Cytomegalovirus cyclin-dependent kinase ortholog vCDK/pUL97 undergoes regulatory interaction with human cyclin H and CDK7 to codetermine viral replication efficiency - Schütz, Martin; Wangen, Christina; Sommerer, Markus; Kögler, Melanie; Eickhoff, Jan; Degenhart, Carsten; Klebl, Bert; Naing, Zin; Egilmezer, Ece; Hamilton, Stuart T.; Rawlinson, William D.; Sticht, Heinrich; et al. (Virus Research, 2023)
Human cytomegalovirus (HCMV) infection is shaped by a tightly regulated interplay between viral and cellular proteins. Distinct kinase activities, such as the viral cyclin-dependent kinase ortholog (vCDK) pUL97 and cellular CDK7 are both crucial for efficient viral replication. Previously, we reported that both kinases, vCDK/pUL97 and CDK7, interact with cyclin H, thereby achieving an enhanced level of kinase activity and overall functionality in viral replication. Here we provide a variety of novel results, as generated on a methodologically extended basis, and present a concept for the codetermination of viral replication efficiency through these kinase activities: (i) cyclin H expression, in various human cell types, is substantially upregulated by strains of HCMV including the clinically relevant HCMV Merlin; (ii) vCDK/pUL97 interacts with human cyclin H in both HCMV-infected and plasmid-transfected cell systems; (iii) a doxycycline-inducible shRNA-dependent knock-down (KD) of cyclin H significantly reduces pUL97 activity (qSox in vitro kinase assay); (iv) accordingly, pUL97 in vitro kinase activity is seen significantly increased upon addition of recombinant cyclin H; (v) as a point of specific importance, human CDK7 activity shows an increase by vCDK/pUL97-mediated trans-stimulation (whereas pUL97 is not stimulated by CDK7); (vi) phosphosite-specific antibodies indicate an upregulated CDK7 phosphorylation upon HCMV infection, as mediated through a pUL97-specific modulatory effect (i.e. shown by pUL97 inhibitor treatment or pUL97-deficient viral mutant); (vii) finally, an efficient KD of cyclin H in primary fibroblasts generally results in an impaired HCMV replication efficiency as measured on protein and genomic levels. These results show evidence for the codetermination of viral replication by vCDK/pUL97, cyclin H and CDK7, thus supporting the specific importance of cyclin H as a central regulatory factor, and suggesting novel targeting options for antiviral drugs.
CRIS-Team Scopus Importer:2023-09-08
Keywords: Codetermination of viral replication; Cyclin H knock-down; Functional importance of cyclin H; Human cytomegalovirus; Modulation of vCDK/pUL97 activity in vitro; Options for antiviral drug targeting; pUL97-mediated CDK7 trans-stimulation; vCDK/pUL97–cyclin binding; Viral cyclin-dependent kinase (CDK) ortholog

DAPK-HSF1 interaction as a positive-feedback mechanism stimulating TNF-induced apoptosis in colorectal cancer cells - Benderska, Natalya; Ivanovska, Jelena; Rau, Tilman; Schulze-Luehrmann, Jan; Mohan, Suma; Chakilam, Saritha; Gandesiri, Muktheshwar; Ziesche, Elisabeth; Fischer, Thomas; Söder, Stephan; Agaimy, Abbas; Distel, Luitpold; et al. (Journal of Cell Science, 2014)
Death-associated protein kinase (DAPK) is a serine-threonine kinase with tumor suppressor function. Previously, we demonstrated that tumor necrosis factor (TNF) induced DAPK-mediated apoptosis in colorectal cancer. However, the protein-protein interaction network associated with TNF-DAPK signaling still remains unclear. We identified HSF1 as a new DAPK phosphorylation target in response to low concentrations of TNF and verified a physical interaction between DAPK and HSF1 both in vitro and in vivo. We show that HSF1 binds to the DAPK promoter. Transient overexpression of HSF1 protein led to an increase in DAPK mRNA level and consequently to an increase in the amount of apoptosis. By contrast, treatment with a DAPK-specific inhibitor as well as DAPK knockdown abolished the phosphorylation of HSF1 at Ser230 (pHSF1(Ser230)). Furthermore, translational studies demonstrated a positive correlation between DAPK and pHSF1(Ser230) protein expression in human colorectal carcinoma tissues. Taken together, our data define a novel link between DAPK and HSF1 and highlight a positive-feedback loop in DAPK regulation under mild inflammatory stress conditions in colorectal tumors. For the first time, we show that under TNF the pro-survival HSF1 protein can be redirected to a pro-apoptotic program.
EVALuna2:6637

Deciphering the regulatory landscape of fetal and adult gamma delta T-cell development at single-cell resolution - Sagar,; Pokrovskii, Maria; Herman, Josip S.; Naik, Shruti; Sock, Elisabeth; Zeis, Patrice; Lausch, Ute; Wegner, Michael; Tanriver, Yakup; Littman, Dan R.; Gruen, Dominic (EMBO Journal, 2020)
gamma delta T cells with distinct properties develop in the embryonic and adult thymus and have been identified as critical players in a broad range of infections, antitumor surveillance, autoimmune diseases, and tissue homeostasis. Despite their potential value for immunotherapy, differentiation of gamma delta T cells in the thymus is incompletely understood. Here, we establish a high-resolution map of gamma delta T-cell differentiation from the fetal and adult thymus using single-cellRNAsequencing. We reveal novel sub-types of immature and mature gamma delta T cells and identify an unpolarized thymic population which is expanded in the blood and lymph nodes. Our detailed comparative analysis reveals remarkable similarities between the gene networks active during fetal and adult gamma delta T-cell differentiation. By performing a combined single-cell analysis ofSox13, Maf,andRorcknockout mice, we demonstrate sequential activation of these factors duringIL-17-producing gamma delta T-cell (gamma delta T17) differentiation. These findings substantially expand our understanding of gamma delta T-cell ontogeny in fetal and adult life. Our experimental and computational strategy provides a blueprint for comparing immune cell differentiation across developmental stages.
CRIS-Team WoS Importer:2020-07-24

Deciphering the regulatory landscape of fetal and adult γδ T-cell development at single-cell resolution - Sagar,; Pokrovskii, Maria; Herman, Josip S.; Naik, Shruti; Sock, Elisabeth; Zeis, Patrice; Lausch, Ute; Wegner, Michael; Tanriver, Yakup; Littman, Dan R.; Grün, Dominic (EMBO Journal, 2020)
γδ T cells with distinct properties develop in the embryonic and adult thymus and have been identified as critical players in a broad range of infections, antitumor surveillance, autoimmune diseases, and tissue homeostasis. Despite their potential value for immunotherapy, differentiation of γδ T cells in the thymus is incompletely understood. Here, we establish a high-resolution map of γδ T-cell differentiation from the fetal and adult thymus using single-cell RNA sequencing. We reveal novel sub-types of immature and mature γδ T cells and identify an unpolarized thymic population which is expanded in the blood and lymph nodes. Our detailed comparative analysis reveals remarkable similarities between the gene networks active during fetal and adult γδ T-cell differentiation. By performing a combined single-cell analysis of Sox13, Maf, and Rorc knockout mice, we demonstrate sequential activation of these factors during IL-17-producing γδ T-cell (γδT17) differentiation. These findings substantially expand our understanding of γδ T-cell ontogeny in fetal and adult life. Our experimental and computational strategy provides a blueprint for comparing immune cell differentiation across developmental stages.
CRIS-Team Scopus Importer:2020-06-16
Keywords: double negative progenitors; fetal and adult thymus; gamma delta T cells; gamma delta T-cell differentiation; single-cell RNA sequencing

Deficiencies in the Mitochondrial Electron Transport Chain Affect Redox Poise and Resistance Toward Colletotrichum higginsianum - Mccollum, Christopher; Geisselsoeder, Sonja; Engelsdorf, Timo; Voitsik, Anna Maria; Voll, Lars (Frontiers in Plant Science, 2019)
To investigate if and how the integrity of the mitochondrial electron transport chain (mETC) influences susceptibility of Arabidopsis toward Colletotrichum higginsianum, we have selected previously characterized mutants with defects at different stages of the mETC, namely, the complex I mutant ndufs4, the complex II mutant sdh2-1, the complex III mutant ucr8-1, and a mutant of the uncoupling protein ucp1-2. Relative to wild type, the selected complex I, II, and III mutants showed decreased total respiration, increased alternative respiration, as well as increased redox charge of the NADP(H) pool and decreased redox charge of the NAD(H) pool in the dark. In the light, mETC mutants accumulated free amino acids, albeit to varying degrees. Glycine and serine, which are involved in carbon recycling from photorespiration, and N-rich amino acids were predominantly increased in mETC mutants compared to the wild type. Taking together the physiological phenotypes of all examined mutants, our results suggest a connection between the limitation in the re-oxidation of reducing equivalents in the mitochondrial matrix and the induction of nitrate assimilation into free amino acids in the cytosol, which seems to be engaged as an additional sink for reducing power. The sdh2-1 mutant was less susceptible to C. higginsianum and did not show hampered salicylic acid (SA) accumulation as previously reported for SDH1 knock-down plants. The ROS burst remained unaffected in sdh2-1, demonstrating that subunit SDH2 is not involved in the control of ROS production and SA signaling by complex II. Moreover, the ndufs4 mutant showed only 20% of C. higginsianum colonization compared to wild type, with the ROS burst and the production of callose papillae being significantly increased compared to wild type. This indicates that a restriction of respiratory metabolism can positively affect pre-penetration resistance of Arabidopsis. Taking metabolite profiling data from all investigated mETC mutants, a strong positive correlation of resistance toward C. higginsianum with NADPH pool size, pyruvate contents, and other metabolites associated with redox poise and energy charge was evident, which fosters the hypothesis that limitations in the mETC can support resistance at post-penetration stages by improving the availability of metabolic power.
CRIS-Team WoS Importer:2019-12-06

Deficient IL-6/Stat3 Signaling, High TLR7, and Type I Interferons in Early Human Alcoholic Liver Disease: A Triad for Liver Damage and Fibrosis - Starkel, Peter; Schnabl, Bernd; Leclercq, Sophie; Komuta, Mina; Bataller, Ramon; Argemi, Josepmaria; Palma, Elena; Chokshi, Shilpa; Hellerbrand, Claus; Maccioni, Luca; Lanthier, Nicolas; Leclercq, Isabelle (Hepatology Communications, 2019)
Mechanisms underlying alcohol-induced liver injury and its progression still remain incompletely understood. Animal models can only address some aspects of the pathophysiology that requires studies directly in humans, which are scarce. We assessed liver inflammatory and immune responses at early stages of alcoholic liver disease in a unique cohort of alcohol-dependent patients undergoing a highly standardized alcohol withdrawal program. In active drinkers, quantitative real-time polymerase chain reaction revealed alcohol-induced activation of tumor necrosis factor alpha, interleukin (IL)-1, and nuclear factor kappa B in liver tissue already at early disease stages. Double immunofluorescence staining indicated that this proinflammatory response was restricted to activated, CD68-positive macrophages. In parallel, down-regulation of IL-6, inhibition of the signal transducer and activator of transcription 3 (Stat3) pathway, as well as blunted cyclin D expression in hepatocytes, reduced proliferation and favored hepatocyte apoptosis. In addition, immunofluorescence and quantitative real-time polymerase chain reaction of liver tissue showed that alcohol also activated the toll-like receptor (TLR) 7-interferon (IFN) axis in hepatocytes, which was confirmed in alcohol-stimulated primary human hepatocytes and precision-cut liver slices in vitro. Activation of the TLR7-IFN axis strongly correlated with liver fibrosis markers and disease progression. Two weeks of abstinence attenuated the inflammatory response but did not allow recovery of the defective Stat3 pathway or effect on fibrosis-associated factors. Conclusion: In humans, inflammation, activation of the TLR7-IFN axis, and inhibition of Stat3-dependent repair mechanisms in early alcoholic liver disease pave the way for fibrosis development and ultimately disease progression.
CRIS-Team WoS Importer:2019-07-19

Deletion of interleukin-6 signal transducer gp130 in small sensory neurons attenuates mechanonociception and down-regulates TRPA1 expression - Malsch, Philipp; Andratsch, Manfred; Vogl, Christian; Link, Andrea; Alzheimer, Christian; Brierley, Stuart M.; Hughes, Patrick A.; Kress, Michaela (The Journal of Neuroscience, 2014)
Glycoprotein 130 (gp130) is the signal transducing receptor subunit for cytokines of the interleukin-6 (IL-6) family, and it is expressed in a multitude of cell types of the immune and nervous system. IL-6-like cytokines are not only key regulators of innate immunity and inflammation but are also essential factors for the differentiation and development of the somatosensory system. Mice with a null mutation of gp130 in primary nociceptive afferents (SNS-gp130(-/-)) are largely protected from hypersensitivity to mechanical stimuli in mouse models of pathological pain. Therefore, we set out to investigate how neuronal gp130 regulates mechanonociception. SNS-gp130(-/-) mice revealed reduced mechanosensitivity to high mechanical forces in the von Frey assay in vivo, and this was associated with a reduced sensitivity of nociceptive primary afferents in vitro. Together with these findings, transient receptor potential ankyrin 1 (TRPA1) mRNA expression was significantly reduced in DRG from SNS-gp130(-/-) mice. This was also reflected by a reduced number of neurons responding with calcium transients to TRPA1 agonists in primary DRG cultures. Downregulation of Trpa1 expression was predominantly discovered in nonpeptidergic neurons, with the deficit becoming evident during stages of early postnatal development. Regulation of Trpa1 mRNA expression levels downstream of gp130 involved the classical Janus kinase family-signal transducer and activator of transcription pathway. Our results closely link proinflammatory cytokines to the expression of TRPA1, both of which have been shown to contribute to hypersensitive pain states. We suggest that gp130 has an essential role in mechanonociception and in the regulation of TRPA1 expression.
EVALuna2:2455

Demonstration of brain region-specific neuronal vulnerability in human iPSC-based model of familial Parkinson's disease - Brazdis, Razvan Marius; Alecu, Julian E.; Marsch, Daniel; Dahms, Annika; Simmnacher, Katrin; Lörentz, Sandra; Brendler, Anna; Schneider, Yanni; Marxreiter, Franz; Roybon, Laurent; Winner, Beate; Xiang, Wei; et al. (Human Molecular Genetics, 2020)
Parkinson's disease (PD) is a neurodegenerative disorder characterized by protein inclusions mostly composed of aggregated forms of α-synuclein (α-Syn) and by the progressive degeneration of midbrain dopaminergic neurons (mDANs), resulting in motor symptoms. While other brain regions also undergo pathologic changes in PD, the relevance of α-Syn aggregation for the preferential loss of mDANs in PD pathology is not completely understood yet. To elucidate the mechanisms of the brain region-specific neuronal vulnerability in PD, we modeled human PD using human-induced pluripotent stem cells (iPSCs) from familial PD cases with a duplication (Dupl) of the α-Syn gene (SNCA) locus. Human iPSCs from PD Dupl patients and a control individual were differentiated into mDANs and cortical projection neurons (CPNs). SNCA dosage increase did not influence the differentiation efficiency of mDANs and CPNs. However, elevated α-Syn pathology, as revealed by enhanced α-Syn insolubility and phosphorylation, was determined in PD-derived mDANs compared with PD CPNs. PD-derived mDANs exhibited higher levels of reactive oxygen species and protein nitration levels compared with CPNs, which might underlie elevated α-Syn pathology observed in mDANs. Finally, increased neuronal death was observed in PD-derived mDANs compared to PD CPNs and to control mDANs and CPNs. Our results reveal, for the first time, a higher α-Syn pathology, oxidative stress level, and neuronal death rate in human PD mDANs compared with PD CPNs from the same patient. The finding implies the contribution of pathogenic α-Syn, probably induced by oxidative stress, to selective vulnerability of substantia nigra dopaminergic neurons in human PD.
CRIS-Team Scopus Importer:2020-05-26

Dendritic Cells Are Dispensable for T Cell Priming and Control of Acute Lymphocytic Choriomeningitis Virus Infection - Hilpert, Cornelia; Sitte, Selina; Matthies, Alexander Oliver; Vöhringer, David (Journal of Immunology, 2016)
Dendritic cells (DCs) are considered to be the major APCs with potent activity for priming of naive CD4 and CD8 T cells. However, T cell priming can also be achieved by other APCs including macrophages, B cells, or even nonhematopoietic cell types. Systemic low-dose infection of mice with lymphocytic choriomeningitis virus (LCMV) results in massive expansion of virus-specific CD4 and CD8 T cells. To determine the role of DCs as APCs and source of type I IFNs in this infection model, we used ?DC mice in which DCs are constitutively ablated because of expression of the diphtheria toxin ? subunit within developing DCs. ?DC mice showed lower serum concentrations of IFN-? and IL-12p40, but normal IFN-? levels during the first days postinfection. No differences were found for proliferation of transferred TCR-transgenic cells during the early phase of infection, suggesting that T cell priming occurred with the same efficiency in wild-type and ?DC mice. Expansion and cytokine expression of endogenous LCMV-specific T cells was comparable between wild-type and ?DC mice during primary infection and upon rechallenge of memory mice. In both strains of infected mice the viral load was reduced below the limit of detection with the same kinetic. Further, germinal center formation and LCMV-specific Ab responses were not impaired in ?DC mice. This indicates that DCs are dispensable as APCs for protective immunity against LCMV infectio
EVALuna2:25882

De novo missense mutations in the NAA10 gene cause severe non-syndromic developmental delay in males and females - Popp, Bernt; Stove, Svein I.; Endele, Sabine; Myklebust, Line M.; Hoyer, Juliane; Sticht, Heinrich; Azzarello-Burri, Silvia; Rauch, Anita; Arnesen, Thomas; Reis, André (European journal of human genetics, 2015)
Recent studies revealed the power of whole-exome sequencing to identify mutations in sporadic cases with non-syndromic intellectual disability. We now identified de novo missense variants in NAA10 in two unrelated individuals, a boy and a girl, with severe global developmental delay but without any major dysmorphism by trio whole-exome sequencing. Both de novo variants were predicted to be deleterious, and we excluded other variants in this gene. This X-linked gene encodes N-alpha-acetyltransferase 10, the catalytic subunit of the NatA complex involved in multiple cellular processes. A single hypomorphic missense variant p.(Ser37Pro) was previously associated with Ogden syndrome in eight affected males from two different families. This rare disorder is characterized by a highly recognizable phenotype, global developmental delay and results in death during infancy. In an attempt to explain the discrepant phenotype, we used in vitro N-terminal acetylation assays which suggested that the severity of the phenotype correlates with the remaining catalytic activity. The variant in the Ogden syndrome patients exhibited a lower activity than the one seen in the boy with intellectual disability, while the variant in the girl was the most severe exhibiting only residual activity in the acetylation assays used. We propose that N-terminal acetyltransferase deficiency is clinically heterogeneous with the overall catalytic activity determining the phenotypic severity.
EVALuna2:9247

De novo missense variants in FBXO11 alter its protein expression and subcellular localization - Gregor, Anne; Meerbrei, Tanja; Gerstner, Thorsten; Toutain, Annick; Lynch, Sally Ann; Stals, Karen; Maxton, Caroline; Lemke, Johannes R.; Bernat, John A.; Bombei, Hannah M.; Foulds, Nicola; Hunt, David; et al. (Human Molecular Genetics, 2022)
Recently, others and we identified de novo FBXO11 (F-Box only protein 11) variants as causative for a variable neurodevelopmental disorder (NDD). We now assembled clinical and mutational information on 23 additional individuals. The phenotypic spectrum remains highly variable, with developmental delay and/or intellectual disability as the core feature and behavioral anomalies, hypotonia and various facial dysmorphism as frequent aspects. The mutational spectrum includes intragenic deletions, likely gene disrupting and missense variants distributed across the protein. To further characterize the functional consequences of FBXO11 missense variants, we analyzed their effects on protein expression and localization by overexpression of 17 different mutant constructs in HEK293 and HeLa cells. We found that the majority of missense variants resulted in subcellular mislocalization and/or reduced FBXO11 protein expression levels. For instance, variants located in the nuclear localization signal and the N-terminal F-Box domain lead to altered subcellular localization with exclusion from the nucleus or the formation of cytoplasmic aggregates and to reduced protein levels in western blot. In contrast, variants localized in the C-terminal Zn-finger UBR domain lead to an accumulation in the cytoplasm without alteration of protein levels. Together with the mutational data, our functional results suggest that most missense variants likely lead to a loss of the original FBXO11 function and thereby highlight haploinsufficiency as the most likely disease mechanism for FBXO11-associated NDDs.
CRIS-Team Scopus Importer:2022-03-04

De novo missense variants in RHOBTB2 cause a developmental and epileptic encephalopathy in humans, and altered levels cause neurological defects in Drosophila - Straub, Jonas; Konrad, Enrico; Grüner, Johanna; Toutain, A.; Bok, L. A.; Cho, M. T.; Crawford, H. P.; Dubbs, H.; Douglas, G.; Jobling, R.; Johnson, D.; Krock, B.; et al. (EUROPEAN JOURNAL OF HUMAN GENETICS, 2019)
CRIS-Team WoS Importer:2019-10-25

De Novo Missense Variants in SLC32A1 Cause a Developmental and Epileptic Encephalopathy Due to Impaired GABAergic Neurotransmission - Platzer, Konrad; Sticht, Heinrich; Bupp, Caleb; Ganapathi, Mythily; Pereira, Elaine M.; Le Guyader, Gwenael; Bilan, Frederic; Henderson, Lindsay B.; Lemke, Johannes R.; Taschenberger, Holger; Brose, Nils; Abou Jamra, Rami; et al. (Annals of Neurology, 2022)
Objective Rare inherited missense variants in SLC32A1, the gene that encodes the vesicular gamma-aminobutyric acid (GABA) transporter, have recently been shown to cause genetic epilepsy with febrile seizures plus. We aimed to clarify if de novo missense variants in SLC32A1 can also cause epilepsy with impaired neurodevelopment. Methods Using exome sequencing, we identified four individuals with a developmental and epileptic encephalopathy and de novo missense variants in SLC32A1. To assess causality, we performed functional evaluation of the identified variants in a murine neuronal cell culture model. Results The main phenotype comprises moderate-to-severe intellectual disability, infantile-onset epilepsy within the first 18 months of life, and a choreiform, dystonic, or dyskinetic movement disorder. In silico modeling and functional analyses reveal that three of these variants, which are located in helices that line the putative GABA transport pathway, result in reduced quantal size, consistent with impaired filling of synaptic vesicles with GABA. The fourth variant, located in the vesicular gamma-aminobutyric acid N-terminus, does not affect quantal size, but increases presynaptic release probability, leading to more severe synaptic depression during high-frequency stimulation. Thus, variants in vesicular gamma-aminobutyric acid can impair GABAergic neurotransmission through at least two mechanisms, by affecting synaptic vesicle filling and by altering synaptic short-term plasticity. Interpretation This work establishes de novo missense variants in SLC32A1 as a novel cause of a developmental and epileptic encephalopathy. Summary for Social Media If Published @platzer_k @lemke_johannes @RamiJamra @Nirgalito @GeneDx The SLC family 32 Member 1 (SLC32A1) is the only protein identified to date, that loads gamma-aminobutyric acid (GABA) and glycine into synaptic vesicles, and is therefore also known as the vesicular GABA transporter (VGAT) or vesicular inhibitory amino acid transporter (VIAAT). Rare inherited missense variants in SLC32A1, the gene that encodes VGAT/vesicular inhibitory amino acid transporter, have recently been shown to cause genetic epilepsy with febrile seizures plus. We aimed to clarify if de novo missense variants in SLC32A1 can also cause epilepsy with impaired neurodevelopment. We report on four individuals with de novo missense variants in SLC32A1 and a developmental and epileptic encephalopathy with infantile onset epilepsy. We establish causality of the variants via in silico modeling and their functional evaluation in a murine neuronal cell culture model. SLC32A1 variants represent a novel genetic etiology in neurodevelopmental disorders with epilepsy and a new GABA-related disease mechanism. ANN NEUROL 2022
CRIS-Team WoS Importer:2022-09-16

De novo mutations in the genome organizer CTCF cause intellectual disability - Gregor, Anne; Oti, Martin; Kouwenhoven, Evelyn N.; Hoyer, Juliane; Sticht, Heinrich; Ekici, Arif Bülent; Kjaergaard, Susanne; Rauch, Anita; Stunnenberg, Hendrik G.; Uebe, Steffen; Vasileiou, Georgia; Reis, André; et al. (American Journal of Human Genetics, 2013)
An increasing number of genes involved in chromatin structure and epigenetic regulation has been implicated in a variety of developmental disorders, often including intellectual disability. By trio exome sequencing and subsequent mutational screening we now identified two de novo frameshift mutations and one de novo missense mutation in CTCF in individuals with intellectual disability, microcephaly, and growth retardation. Furthermore, an individual with a larger deletion including CTCF was identified. CTCF (CCCTC-binding factor) is one of the most important chromatin organizers in vertebrates and is involved in various chromatin regulation processes such as higher order of chromatin organization, enhancer function, and maintenance of three-dimensional chromatin structure. Transcriptome analyses in all three individuals with point mutations revealed deregulation of genes involved in signal transduction and emphasized the role of CTCF in enhancer-driven expression of genes. Our findings indicate that haploinsufficiency of CTCF affects genomic interaction of enhancers and their regulated gene promoters that drive developmental processes and cognition.
EVALuna2:9184

De novo variants in ATP2B1 lead to neurodevelopmental delay - Rahimi, Meer Jacob; Urban, Nicole; Wegler, Meret; Sticht, Heinrich; Schaefer, Michael; Popp, Bernt; Gaunitz, Frank; Morleo, Manuela; Nigro, Vincenzo; Maitz, Silvia; Mancini, Grazia M.S.; Ruivenkamp, Claudia; et al. (American Journal of Human Genetics, 2022)
Calcium (Ca2+) is a universal second messenger involved in synaptogenesis and cell survival; consequently, its regulation is important for neurons. ATPase plasma membrane Ca2+ transporting 1 (ATP2B1) belongs to the family of ATP-driven calmodulin-dependent Ca2+ pumps that participate in the regulation of intracellular free Ca2+. Here, we clinically describe a cohort of 12 unrelated individuals with variants in ATP2B1 and an overlapping phenotype of mild to moderate global development delay. Additional common symptoms include autism, seizures, and distal limb abnormalities. Nine probands harbor missense variants, seven of which were in specific functional domains, and three individuals have nonsense variants. 3D structural protein modeling suggested that the variants have a destabilizing effect on the protein. We performed Ca2+ imaging after introducing all nine missense variants in transfected HEK293 cells and showed that all variants lead to a significant decrease in Ca2+ export capacity compared with the wild-type construct, thus proving their pathogenicity. Furthermore, we observed for the same variant set an incorrect intracellular localization of ATP2B1. The genetic findings and the overlapping phenotype of the probands as well as the functional analyses imply that de novo variants in ATP2B1 lead to a monogenic form of neurodevelopmental disorder.
CRIS-Team Scopus Importer:2022-05-27
Keywords: abnormal behavior; ATP2B1; calcium homeostasis; de novo; development delay; intellectual disability; neurodevelopmental disorder; seizure

De novo variants in CNOT9 cause a neurodevelopmental disorder with or without epilepsy. - von Wintzingerode, Lydia; Ben-Zeev, Bruria; Cesario, Claudia; Chan, Katie M.; Depienne, Christel; Elpeleg, Orly; Iascone, Maria; Kelley, Whitley V.; Nassogne, Marie Cécile; Niceta, Marcello; Pezzani, Lidia; Rahner, Nils; et al. (Genetics in Medicine, 2023)
PURPOSE: The study aimed to clinically and molecularly characterize the neurodevelopmental disorder associated with heterozygous de novo variants in CNOT9. METHODS: Individuals were clinically examined. Variants were identified using exome or genome sequencing. These variants were evaluated using in silico predictions, and their functional relevance was further assessed by molecular models and research in the literature. The variants have been classified according to the criteria of the American College of Medical Genetics. RESULTS: We report on 7 individuals carrying de novo missense variants in CNOT9, p.(Arg46Gly), p.(Pro131Leu), and p.(Arg227His), and, recurrent in 4 unrelated individuals, p.(Arg292Trp). All affected persons have developmental delay/intellectual disability, with 5 of them showing seizures. Other symptoms include muscular hypotonia, facial dysmorphism, and behavioral abnormalities. Molecular modeling predicted that the variants are damaging and would lead to reduced protein stability or impaired recognition of interaction partners. Functional analyses in previous studies showed a pathogenic effect of p.(Pro131Leu) and p.(Arg227His). CONCLUSION: We propose CNOT9 as a novel gene for neurodevelopmental disorder and epilepsy.
EVALuna2:553803

De Novo Variants in MAPK8IP3 Cause Intellectual Disability with Variable Brain Anomalies - Platzer, Konrad; Sticht, Heinrich; Edwards, Stacey L.; Allen, William; Angione, Kaitlin M.; Bonati, Maria T.; Brasington, Campbell; Cho, Megan T.; Demmer, Laurie A.; Falik-Zaccai, Tzipora; Gamble, Candace N.; Hellenbroich, Yorck; et al. (American Journal of Human Genetics, 2019)
Using exome sequencing, we have identified de novo variants in MAPK8IP3 in 13 unrelated individuals presenting with an overlapping phenotype of mild to severe intellectual disability. The de novo variants comprise six missense variants, three of which are recurrent, and three truncating variants. Brain anomalies such as perisylvian polymicrogyria, cerebral or cerebellar atrophy, and hypoplasia of the corpus callosum were consistent among individuals harboring recurrent de novo missense variants. MAPK8IP3 has been shown to be involved in the retrograde axonal-transport machinery, but many of its specific functions are yet to be elucidated. Using the CRISPR-Cas9 system to target six conserved amino acid positions in Caenorhabditis elegans, we found that two of the six investigated human alterations led to a significantly elevated density of axonal lysosomes, and five variants were associated with adverse locomotion. Reverse-engineering normalized the observed adverse effects back to wild-type levels. Combining genetic, phenotypic, and functional findings, as well as the significant enrichment of de novo variants in MAPK8IP3 within our total cohort of 27,232 individuals who underwent exome sequencing, we implicate de novo variants in MAPK8IP3 as a cause of a neurodevelopmental disorder with intellectual disability and variable brain anomalies.
CRIS-Team WoS Importer:2019-02-27

De novo variants in MAPK8IP3 cause intellectual disability with variable brain anomalies - Platzer, K.; Sticht, Heinrich; Edwards, S. L.; Allen, W.; Angione, K. M.; Bonati, M. T.; Brasington, C.; Cho, M. T.; Demmer, L. A.; Falik-Zaccai, T.; Gamble, C. N.; Hellenbroich, Y.; et al. (EUROPEAN JOURNAL OF HUMAN GENETICS, 2019)
CRIS-Team WoS Importer:2019-10-25

De novo variants in PAK1 lead to intellectual disability with macrocephaly and seizures - Horn, Susanne; Au, Margaret; Basel-Salmon, Lina; Bayrak-Toydemir, Pinar; Chapin, Alexander; Cohen, Lior; Elting, Mariet W.; Graham, John M.; Gonzaga-Jauregui, Claudia; Konen, Osnat; Holzer, Max; Lemke, Johannes; et al. (Brain, 2019)
Using trio exome sequencing, we identified de novo heterozygous missense variants in PAK1 in four unrelated individuals with intellectual disability, macrocephaly and seizures. PAK1 encodes the p21-activated kinase, a major driver of neuronal development in humans and other organisms. In normal neurons, PAK1 dimers reside in a trans-inhibited conformation, where each autoinhibitory domain covers the kinase domain of the other monomer. Upon GTPase binding via CDC42 or RAC1, the PAK1 dimers dissociate and become activated. All identified variants are located within or close to the autoinhibitory switch domain that is necessary for trans-inhibition of resting PAK1 dimers. Protein modelling supports a model of reduced ability of regular autoinhibition, suggesting a gain of function mechanism for the identified missense variants. Alleviated dissociation into monomers, autophosphorylation and activation of PAK1 influences the actin dynamics of neurite outgrowth. Based on our clinical and genetic data, as well as the role of PAK1 in brain development, we suggest that gain of function pathogenic de novo missense variants in PAK1 lead to moderate-to-severe intellectual disability, macrocephaly caused by the presence of megalencephaly and ventriculomegaly, (febrile) seizures and autism-like behaviour.
CRIS-Team Scopus Importer:2019-11-08
Keywords: de novo; exome sequencing; intellectual disability; macrocephaly; seizures

De Novo Variants in RAB11B Cause Various Degrees of Global Developmental Delay and Intellectual Disability in Children - Ahmad, Natalie; Fazeli, Walid; Schließke, Sophia; Lesca, Gaetan; Gokce-Samar, Zeynep; Mekbib, Kedous Y.; Jin, Sheng Chih; Burton, Jennifer; Hoganson, George; Petersen, Andrea; Gracie, Sara; Granger, Leslie; et al. (Pediatric Neurology, 2023)
Background: RAB11B was described previously once with a severe form of intellectual disability. We aim at validation and delineation of the role of RAB11B in neurodevelopmental disorders. Methods: We present seven novel individuals with disease-associated variants in RAB11B when compared with the six cases described in the literature. We performed a cross-sectional analysis to identify the clinical spectrum and the core phenotype. Additionally, structural effects of the variants were assessed by molecular modeling. Results: Seven distinct de novo missense variants were identified, three of them recurrent (p.(Gly21Arg), p.(Val22Met), and p.(Ala68Thr)). Molecular modeling suggests that those variants either affect the nucleotide binding (at amino acid positions 21, 22, 33, 68) or the interaction with effector molecules (at positions 72 and 75). Our data confirmed the main manifestations as neurodevelopmental disorder with intellectual disability (85%), muscular hypotonia (83%), structural brain anomalies (77%), and visual impairment (70%). Combined analysis indicates a genotype-phenotype correlation; variants impacting the nucleotide binding cause a severe phenotype with intellectual disability, and variants outside the binding pocket lead to a milder phenotype with epilepsy. Conclusions: We confirm that disease-associated missense variants in RAB11B cause a neurodevelopmental disorder and suggest a genotype-phenotype correlation based on the impact on nucleotide binding functionality of RAB11B.
CRIS-Team Scopus Importer:2023-09-29
Keywords: Genotype-phenotype correlation; GTPase; Neurodevelopmental disorder; RAB11A; RAB11B

De novo variants in SNAP25 cause an early-onset developmental and epileptic encephalopathy - Kloeckner, Chiara; Sticht, Heinrich; Zacher, Pia; Popp, Bernt; Babcock, Holly E.; Bakker, Dewi P.; Barwick, Katy; Bonfert, Michaela; Bonnemann, Carsten G.; Brilstra, Eva H.; Chung, Wendy K.; Clarke, Angus J.; et al. (Genetics in Medicine, 2020)
Purpose: This study aimsed to provide a comprehensive description of the phenotypic and genotypic spectrum of SNAP25 developmental and epileptic encephalopathy (SNAP25-DEE) by reviewing newly identified and previously reported individuals. Methods: Individuals harboring heterozygous missense or loss-of-function variants in SNAP25 were assembled through collaboration with international colleagues, matchmaking platforms, and literature review. For each individual, detailed phenotyping, classification, and structural modeling of the identified variant were performed. Results: The cohort comprises 23 individuals with pathogenic or likely pathogenic de novo variants in SNAP25. Intellectual disability and early-onset epilepsy were identified as the core symptoms of SNAP25-DEE, with recurrent findings of movement disorders, cerebral visual impairment, and brain atrophy. Structural modeling for all variants predicted possible functional defects concerning SNAP25 or impaired interaction with other components of the SNARE complex. Conclusion: We provide a comprehensive description of SNAP25-DEE with intellectual disability and early-onset epilepsy mostly occurring before the age of two years. These core symptoms and additional recurrent phenotypes show an overlap to genes encoding other components or associated proteins of the SNARE complex such as STX1B, STXBP1, or VAMP2. Thus, these findings advance the concept of a group of neurodevelopmental disorders that may be termed “SNAREopathies.”.
CRIS-Team Scopus Importer:2020-12-25

De Novo Variants in the F-Box Protein FBXO11 in 20 Individuals with a Variable Neurodevelopmental Disorder - Gregor, Anne; Sadleir, Lynette G.; Asadollahi, Reza; Azzarello-Burri, Silvia; Battaglia, Agatino; Ousager, Lilian Bomme; Boonsawat, Paranchai; Bruel, Ange-Line; Buchert, Rebecca; Calpena, Eduardo; Cogne, Benjamin; Dallapiccola, Bruno; et al. (American Journal of Human Genetics, 2018)
Next-generation sequencing combined with international data sharing has enormously facilitated identification of new disease-associated genes and mutations. This is particularly true for genetically extremely heterogeneous entities such as neurodevelopmental disorders (NDDs). Through exome sequencing and world-wide collaborations, we identified and assembled 20 individuals with de novo variants in FBXO11. They present with mild to severe developmental delay associated with a range of features including short (4/20) or tall (2/20) stature, obesity (5/20), microcephaly (4/19) or macrocephaly (2/19), behavioral problems (17/20), seizures (5/20), cleft lip or palate or bifid uvula (3/20), and minor skeletal anomalies. FBXO11 encodes a member of the F-Box protein family, constituting a subunit of an E3-ubiquitin ligase complex. This complex is involved in ubiquitination and proteasomal degradation and thus in controlling critical biological processes by regulating protein turnover. The identified de novo aberrations comprise two large deletions, ten likely gene disrupting variants, and eight missense variants distributed throughout FBXO11. Structural modeling for missense variants located in the CASH or the Zinc-finger UBR domains suggests destabilization of the protein. This, in combination with the observed spectrum and localization of identified variants and the lack of apparent genotype-phenotype correlations, is compatible with loss of function or haploinsufficiency as an underlying mechanism. We implicate de novo missense and likely gene disrupting variants in FBXO11 in a neurodevelopmental disorder with variable intellectual disability and various other features.
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De novo variants in the PABP domain of PABPC1 lead to developmental delay - Wegler, Meret; Jia, Xiangbin; Alders, Marielle; Bouman, Arjan; Chen, Jia; Duan, Xinyu; Lauzon, Julie L.; Mathijssen, Inge B.; Sticht, Heinrich; Syrbe, Steffen; Tan, Senwei; Guo, Hui; et al. (Genetics in Medicine, 2022)
Purpose: The study aimed to investigate the role of PABPC1 in developmental delay (DD). Methods: Children were examined by geneticists and pediatricians. Variants were identified using exome sequencing and standard downstream bioinformatics pipelines. We performed in silico molecular modeling and coimmunoprecipitation to test if the variants affect the interaction between PABPC1 and PAIP2. We performed in utero electroporation of mouse embryo brains to enlighten the function of PABPC1. Results: We describe 4 probands with an overlapping phenotype of DD, expressive speech delay, and autistic features and heterozygous de novo variants that cluster in the PABP domain of PABPC1. Further symptoms were seizures and behavioral disorders. Molecular modeling predicted that the variants are pathogenic and would lead to decreased binding affinity to messenger RNA metabolism-related proteins, such as PAIP2. Coimmunoprecipitation confirmed this because it showed a significant weakening of the interaction between mutant PABPC1 and PAIP2. Electroporation of mouse embryo brains showed that Pabpc1 knockdown decreases the proliferation of neural progenitor cells. Wild-type Pabpc1 could rescue this disturbance, whereas 3 of the 4 variants did not. Conclusion: Pathogenic variants in the PABP domain lead to DD, possibly because of interference with the translation initiation and subsequently an impaired neurogenesis in cortical development.
CRIS-Team Scopus Importer:2022-05-20
Keywords: Epilepsy; Exome; Intellectual disability; Neural progenitor cells; Neurodevelopmental disorder

Dentate gyrus astrocytes exhibit layer-specific molecular, morphological and physiological features - Karpf, Julian; Unichenko, Petr; Chalmers, Nicholas; Beyer, Felix; Wittmann, Marie-Theres; Schneider, Julia; Fidan, Elif; Reis, André; Beckervordersandforth, Jan; Brandner, Sebastian; Liebner, Stefan; Falk, Sven; et al. (Nature Neuroscience, 2022)
Neuronal heterogeneity has been established as a pillar of higher central nervous system function, but glial heterogeneity and its implications for neural circuit function are poorly understood. Here we show that the adult mouse dentate gyrus (DG) of the hippocampus is populated by molecularly distinct astrocyte subtypes that are associated with distinct DG layers. Astrocytes localized to different DG compartments also exhibit subtype-specific morphologies. Physiologically, astrocytes in upper DG layers form large syncytia, while those in lower DG compartments form smaller networks. Astrocyte subtypes differentially express glutamate transporters, which is associated with different amplitudes of glutamate transporter-mediated currents. Key molecular and morphological features of astrocyte diversity in the mice DG are conserved in humans. This adds another layer of complexity to our understanding of brain network composition and function, which will be crucial for further studies on astrocytes in health and disease.
CRIS-Team Scopus Importer:2022-12-09

Desert Hedgehog links transcription factor Sox10 to perineurial development. - Küspert, Melanie; Weider, Matthias; Müller, Jana; Wegner, Michael; et al. (Journal of Neuroscience, 2012)
Schwann cells are the main glial cell type in the PNS. They develop along nerves during embryogenesis and rely on theHMGdomain containing Sox10 transcription factor for specification, lineage progression, and terminal differentiation. Sox10 deletion in immature Schwann cells caused peripheral nerve defects in mice that were not restricted to this glial cell type, although expression in the nerve and gene loss were. Formation of the perineurium as the protecting sheath was, for instance, heavily compromised. This resembled the defect observed after loss of Desert hedgehog (Dhh) in mice. Here we show that Sox10 activates Dhh expression in Schwann cells via an enhancer that is located in intron 1 of the Dhh gene. Sox10 binds this enhancer in monomeric form via several sites. Mutation of these sites abolishes both Schwann-cell-specific activity and Sox10 responsiveness in vitro and in transgenic mouse embryos. This argues that Sox10 activates Dhh expression by direct binding to the enhancer and by increasing Dhh levels promotes formation of the perineurial sheath. This represents the first mechanism for a non-cell-autonomous function of Sox10 during peripheral nerve development. © 2012 the authors.
UnivIS-Import:2015-03-09:Pub.2012.med.IB.LPCIPDBI.desert

Design Aspects for Sensitive Metasurface-Based THz Biosensing in Aqueous Solutions - Richter, Merle; Weisenstein, Christian; Wigger, Anna K.; Boßerhoff, Anja Katrin; Bolivar, Peter Haring (2022 47TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES (IRMMW-THZ 2022), 2022)
CRIS-Team WoS Importer:2022-11-25

Detection and quantification of cellular senescence in human melanocytes and melanoma cell lines - Zimmermann, Tom; Pommer, Michaela; Kluge, Viola; Chiheb, Chafia; Mühlich, Susanne; Boßerhoff, Anja Katrin (JOURNAL DER DEUTSCHEN DERMATOLOGISCHEN GESELLSCHAFT, 2022)
CRIS-Team WoS Importer:2022-09-23

Detection of Cellular Senescence in Human Primary Melanocytes and Malignant Melanoma Cells In Vitro - Zimmermann, Tom; Pommer, Michaela; Kluge, Viola; Chiheb, Chafia; Mühlich, Susanne; Boßerhoff, Anja Katrin (Cells, 2022)
Detection and quantification of senescent cells remain difficult due to variable phenotypes and the absence of highly specific and reliable biomarkers. It is therefore widely accepted to use a combination of multiple markers and cellular characteristics to define senescent cells in vitro. The exact choice of these markers is a subject of ongoing discussion and usually depends on objective reasons such as cell type and treatment conditions, as well as subjective considerations including feasibility and personal experience. This study aims to provide a comprehensive comparison of biomarkers and cellular characteristics used to detect senescence in melanocytic systems. Each marker was assessed in primary human melanocytes that overexpress mutant BRAFV600E, as it is commonly found in melanocytic nevi, and melanoma cells after treatment with the chemotherapeutic agent etoposide. The combined use of these two experimental settings is thought to allow profound conclusions on the choice of senescence biomarkers when working with melanocytic systems. Further, this study supports the development of standardized senescence detection and quantification by providing a comparative analysis that might also be helpful for other cell types and experimental conditions.
CRIS-Team Scopus Importer:2022-05-13
Keywords: beta-galactosidase; melanocyte; melanoma; senescence

Detection of central nervous system tissue in meat and meat products with a newly developed immunoassay selective for Myelin proteolipid protein - Sandmeier, Barbara; Bäuerlein, Rainer; Villmann, Carmen; Düthorn, Tina; Gareis, Manfred; Becker, Cord-Michael; Pischetsrieder, Monika (Food Chemistry, 2007)
Bovine spongiform encephalopathy (BSE) is most likely transmitted by the consumption of central nervous system (CNS) tissue of infected animals. In this study, an immunochemical assay for CNS in meat and meat products was developed using an antibody against Myelin proteolipid protein (PLP), which is very specifically expressed in the CNS. Solvent extraction of CNS-contaminated meat yielded a highly enriched PLP fraction. Subsequent Western blot analysis specifically detected the PLP band at 29 kDa. The detection limit for unprocessed CNS in raw meat was less than 0.025% and the quantification limit was calculated to be 0.049%. The PLP epitope was relatively stable during storage at 5 °C or -21 °C and during heating at 75 °C and 95 °C. Amounts of 0.1% CNS could be reliably detected in cooked bologna type sausage, cooked liver sausage and fermented sausage. Thus, the new assay allows highly specific and sensitive determination of CNS contaminations in meat and meat products. © 2007 Elsevier Ltd. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2007.nat.dchph.llmch.detect
Keywords: Bovine spongiform encephalopathy; Central nervous system; Myelin proteolipid protein; Solvent extraction; Western blot

Detection of Human Tumor Markers with THz Metamaterials - Weisenstein, C.; Schaar, Dominik; Schmeck, M.; Wigger, A. K.; Boßerhoff, Anja Katrin; Bolivar, P. Haring (International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz, 2018)
THz bioanalytical techniques are already proven as a viable tool for the label-free detection of biomolecules. But still, significant improvement of THz sensing techniques is needed to reach application relevant sensitivity levels. We present the label-free THz sensing of human tumor markers using a highly sensitive metamaterial based THz biosensor. High affinity binding of the specific protein to DNA is utilized for localized functionalization to further enhance the detection sensitivity.
CRIS-Team Scopus Importer:2022-08-05

Developmental regulation of glycine receptors at efferent synapses of the murine cochlea - Buerbank, Stefanie; Becker, Kristina; Becker, Cord-Michael; Brandt, Niels; Engel, Jutta; Knipper, Marlies; Schick, Bernhard; Dlugaiczyk, Julia (Histochemistry and Cell Biology, 2011)
Efferent olivocochlear feedback innervation modulates the stream of auditory information from cochlea to brainstem by regulating auditory nerve activity and controlling the contribution of cochlear outer hair cells to basilar membrane motion. In our previous work, we gave a first description of glycine receptors (GlyRs) in the rat cochlea indicating a possible localization at efferent cochlear synapses. Here, we analyze the developmental regulation of GlyR transcripts and protein within the developing murine organ of Corti (postnatal days P0-P21). Using quantitative RT-PCR, GlyR?1 and ?2 were identified as the predominant GlyR? subunit transcripts before the onset of hearing (
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Development and degeneration of dorsal root ganglia in the absence of the HMG-domain transcription factor Sox10 - Wegner, Michael; Stolt, Claus; et al. (Mechanisms of Development, 2001)
The HMG-domain transcription factor Sox10 is essential for the development of various neural crest derived lineages including glia and neurons of the peripheral nervous system (PNS). Within the PNS the most striking defect is the complete absence of glial differentiation whereas neurogenesis seemed initially normal. A degeneration of motoneurons and sensory neurons occurred later in development. The mechanism that leads to the dramatic effects on the neural crest derived cell lineages in the dorsal root ganglia (DRG), however, has not been examined up to now. Here, we provide a detailed analysis of proliferation and apoptosis in the DRG during the time of their generation and lineage segregation (between E 9.5 and E 11.5). We show that both increased apoptosis as well as decreased proliferation of neural crest cells contribute to the observed hypomorphism. © 2001 Elsevier Science Ireland Ltd. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2001.med.IB.LPCIPDBI.develo

Development of a Dot Blot Assay for the Rapid Detection of Central Nervous System Tissue on Meat and Contact Surfaces - Bäuerlein, Rainer; Sandmeier, Barbara; Villmann, Carmen; Hammon, Antje; Gareis, Manfred; Becker, Cord-Michael; Pischetsrieder, Monika (Journal of Agricultural and Food Chemistry, 2008)
As a potential transmitter of bovine spongiform encephalopathy (BSE), tissue from bovine central nervous system (CNS) is not accepted in meat and meat products. Western blot analysis of the CNS marker myelin proteolipid protein (PLP) detects CNS contamination selectively and sensitively. In this study, a rapid dot blot assay using an anti-PLP antibody was developed to screen CNS contamination of meat and contact surfaces. The detection limit was 0.01% bovine brain in minced bovine muscle. When applied to a swab test, down to 0.5 mg of CNS tissue on meat or other surfaces was detectable. Other offal tissues or peripheral nerves did not interfere with the assay. The test allows a differentiation between mammalian and avian CNS but not among mammalian species. The swab test was applied immediately after slaughtering at several areas of the bovine head. CNS was not detectable at any region which may enter the food chain. © 2008 American Chemical Society.
UnivIS-Import:2015-03-09:Pub.2008.nat.dchph.llmch.develo
Keywords: Bovine spongiform encephalopathy; Central nervous system; Dot blot; Meat; Myelin proteolipid protein; PLP; Swab test

Development of an in vitro model to study hepatitis C virus effects on hepatocellular lipotoxicity and lipid metabolism - Koletzko, Leandra; Mahli, Abdo; Hellerbrand, Claus (Pathology Research and Practice, 2018)
Hepatic steatosis is common in patients infected with hepatitis C virus (HCV). Particularly in patients infected with non-genotype 3 HCV, hepatic steatosis is closely related to factors of the metabolic syndrome such as hyperlipidemia. However, the molecular mechanisms involved in this "metabolic" steatosis in non-3 genotype HCV infections are not well understood. Here, we aimed to develop an in vitro model to study the effect of genotype 1 HCV infection on hepatic lipotoxicity and lipid metabolism. Cellular lipid accumulation was induced in Huh-7 hepatoma cells transfected with HCV genotype 1b replicon (HCV+) by incubation with increasing doses of palmitic acid (C16:0) or oleic acid (C18:1 n-9) complexed to albumin mimicking hyperlipidemic conditions. Mock transfected hepatoma cells (HCV-) were used as controls. Incubation with oleic acid concentrations as high as 0.5 mM did not induce toxic effects in HCV+ or HCV- cells. In contrast, incubation with palmitic acid caused dose-dependently cytotoxic effects which were more pronounced in HCV+ compared to HCV- cells. Further analysis with subtoxic palmitic and oleic acid concentrations revealed a higher uptake of fatty acids and intracellular triglyceride accumulation in HCV+ compared to HCV- cells. Carnitine palmitoyltransferase I (CPT1) expression, indicative of mitochondrial beta-oxidation, was markedly stimulated by lipid exposure in HCV+ but not in HCV- cells. Furthermore, heme oxygenase 1 (HMOX1) expression levels increased in FA stimulated cells, and this increase was significantly higher in HCV+ compared to HCV- cells. In contrast, expression of the key enzymes of hepatic de novo lipogenesis fatty acid synthase (FASN) and stearoyl-CoA desaturase (SCD-1) was significantly reduced upon oleate exposure in HCV- but not in HCV+ cells. In summary, our newly developed cell culture model revealed effects of HCV genotype 1b infection on metabolic susceptibility to lipid accumulation and toxicity particularly to saturated lipids. These results may indicate that HCV (genotype 1b) infected individuals with hyperlipidemia may benefit from dietary or pharmacological intervention.
EVALuna2:35809

Diagnostic Yield and Novel Candidate Genes by Exome Sequencing in 152 Consanguineous Families With Neurodevelopmental Disorders - Reuter, Miriam; Tawamie, Hasan; Buchert, Rebecca; Gebril, Ola Hosny; Froukh, Tawfiq; Thiel, Christian; Uebe, Steffen; Ekici, Arif Bülent; Krumbiegel, Mandy; Zweier, Christiane; Hoyer, Juliane; Eberlein, Karolin; et al. (JAMA Psychiatry, 2017)
Autosomal recessive inherited neurodevelopmental disorders are highly heterogeneous, and many, possibly most, of the disease genes are still unknown.To promote the identification of disease genes through confirmation of previously described genes and presentation of novel candidates and provide an overview of the diagnostic yield of exome sequencing in consanguineous families.Autozygosity mapping in families and exome sequencing of index patients were performed in 152 consanguineous families (the parents descended from a same ancestor) with at least 1 offspring with intellectual disability (ID). The study was conducted from July 1, 2008, to June 30, 2015, and data analysis was conducted from July 1, 2015, to August 31, 2016.Of the 152 consanguineous families enrolled, 1 child (in 45 families [29.6%]) or multiple children (107 families [70.4%]) had ID; additional features were present in 140 of the families (92.1%). The mean (SD) age of the children was 10.3 (9.0) years, and 171 of 297 (57.6%) were male. In 109 families (71.7%), potentially protein-disrupting and clinically relevant variants were identified. Of these, a clear clinical genetic diagnosis was made in 56 families (36.8%) owing to 57 (likely) pathogenic variants in 50 genes already established in neurodevelopmental disorders (46 autosomal recessive, 2 X-linked, and 2 de novo) or in 7 previously proposed recessive candidates. In 5 of these families, potentially treatable disorders were diagnosed (mutations in PAH, CBS, MTHFR, CYP27A1, and HIBCH), and in 1 family, 2 disease-causing homozygous variants in different genes were identified. In another 48 families (31.6%), 52 convincing recessive variants in candidate genes that were not previously reported in regard to neurodevelopmental disorders were identified. Of these, 14 were homozygous and truncating in GRM7, STX1A, CCAR2, EEF1D, GALNT2, SLC44A1, LRRIQ3, AMZ2, CLMN, SEC23IP, INIP, NARG2, FAM234B, and TRAP1. The diagnostic yield was higher in individuals with severe ID (35 of 77 [45.5%]), in multiplex families (42 of 107 [39.3%]), in patients with additional features (30 of 70 [42.9%]), and in those with remotely related parents (15 of 34 [44.1%]).Because of the high diagnostic yield of 36.8% and the possibility of identifying treatable diseases or the coexistence of several disease-causing variants, using exome sequencing as a first-line diagnostic approach in consanguineous families with neurodevelopmental disorders is recommended. Furthermore, the literature is enriched with 52 convincing candidate genes that are awaiting confirmation in independent families.
EVALuna2:9388

Different binding domains in the metabotropic glutamat receptor type 7b for Filamin-A, PP1C, PICK1 and Syntenin allow the formation of multimeric protein complexes. - Enz, Ralf; et al. (Biochemical Journal, 2003)
UnivIS-Import:2017-12-18:Pub.2003.med.IB.profes_1.differ

Differential activity of transcription factor Sox9 in early and adult oligodendroglial progenitor cells - Hassel, Lisa; Fröb, Franziska; Küspert, Melanie; Hillgärtner, Simone; Arnold, Philipp; Huang, Wenhui; Kirchhoff, Frank; Wegner, Michael (Glia, 2023)
The high-mobility-group domain-containing transcription factor Sox9 confers glial competence to neuroepithelial precursors in the developing central nervous system and is an important determinant of astroglial and oligodendroglial specification. In oligodendroglial cells, it remains expressed in oligodendrocyte progenitor cells (OPCs) of the developing nervous system, but is shut off in differentiating oligodendrocytes as well as in OPCs that persist in the adult nervous system. To better understand the role of Sox9 in OPCs, we generated mouse models that allowed oligodendroglial expression of a Sox9 transgene during development or in the adult. With transgene expression beginning in the last trimester of pregnancy, the number of OPCs increased dramatically, followed by comparable gains in the number of pre-myelinating and myelinating oligodendrocytes as assessed by marker gene expression. This argues that Sox9 boosts oligodendrogenesis during ontogenetic development at all stages, including terminal oligodendrocyte differentiation. When Sox9 transgene expression started in the adult, many transgene-expressing OPCs failed to maintain their progenitor cell identity and instead converted into myelinating oligodendrocytes. As infrequent and inefficient differentiation of adult OPCs is one of the main obstacles to effective remyelination in demyelinating diseases such as Multiple Sclerosis, increased Sox9 levels in adult OPCs may substantially increase their remyelination capacity.
CRIS-Team Scopus Importer:2023-04-21
Keywords: glia; HMG; myelin; oligodendrocyte; Sox; Sry

Differential contribution of EF-hands to the Ca²?-dependent activation in the plant two-pore channel TPC1 - Schulze, Christina; Sticht, Heinrich; Meyerhoff, Petra; Dietrich, Petra (Plant Journal, 2011)
Two-pore channels (TPC) have been established as components of calcium signalling networks in plants and animals. In plants, TPC1 in the vacuolar membrane is gated open upon binding of calcium in a voltage-dependent manner. Here, we analyzed the molecular mechanism of the Ca²?-dependent activity of TPC1 from Arabidopsis thaliana, using site-directed mutagenesis of its two canonical EF-hands. Wild-type TPC1 and TPC1-D335A with a mutated first Ca²? ligand in EF-hand 1 produced channels that retained their voltage- and Ca²?-dependent gating characteristics, but were less sensitive at Ca²? concentrations < 200 ?m. Additional mutation of the first Ca²? ligand in EF-hand 2 resulted in silent TPC1-D335A/D376A channels. Similarly, the single mutant TPC1-D376A could not be activated up to 1 mm Ca²?, indicating that the second EF-hand is essential for the Ca²?-dependent channel gating. Molecular modeling suggests that EF-hand 1 displays a low-affinity Ca²?/Mg²?-binding site, while EF-hand 2 represents a high-affinity Ca²?-binding site. Together, our data prove that EF-hand 2 is responsible for the Ca²?-receptor characteristics of TPC1, while EF-hand 1 is a structural site required to enable channel responses at physiological changes in Ca²? concentration.
EVALuna2:26267

Differential expression and dynamic changes of murine NEDD9 in progenitor cells of diverse tissues. - Wegner, Michael; et al. (Gene Expression Patterns, 2008)
NEDD9 is a scaffolding protein in the integrin signaling pathway that is involved in cell adhesion dynamics. Little is known of the cellular localization of NEDD9 expression during embryonic development. In the present study, we have analyzed NEDD9 mRNA expression in the mouse and identified new relevant expression sites. In addition, we have characterized NEDD9 protein expression pattern for the first time in mammals. At E9.5-E10.5, high levels of Nedd9 and the neurogenic transcription factor neurogenin-2 (Ngn2) were found to largely overlap in two discrete domains of the trunk neural tube along its dorso-ventral axis, with Nedd9 extending to more ventral regions of the ventricular zone and Ngn2 differentially expressed in neuronally committed progenitors of the intermediate zone. At encephalic and trunk levels of the neural tube, NEDD9 was present in Sox2+ progenitor cell populations mostly generating Ngn2+ and/or Nurr1+ cells. A sharp down-regulation of NEDD9 expression was found in cells upon lineage commitment, as observed in Nurr1+ and Ngn2+ mesencephalic dopaminergic and brainstem neuronal progenitors. In other tissues/organs, i.e. prospective heart, retina, olfactory epithelium, gonads, cartilage, gut and pituitary gland, NEDD9 was found to be co-expressed with Sox2, RXR alpha and/or Nurr1-like proteins, suggesting that NEDD9 expression is confined to early progenitors involved in diverse organogenesis and that it may depend on the repertoire and levels of retinoic acid co-receptors expressed by those cells. © 2008 Elsevier B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2008.med.IB.LPCIPDBI.differ
Keywords: Adaptor; Cas-L; HEF1; Multipotency; Neural tube; Neurogenin; Nurr1; Retinoic acid; Ventral midbrain

Differential vulnerability of adult neurogenic niches to dosage of the neurodevelopmental-disorder linked gene Foxg1 - Schäffner, Iris; Wittmann, Marie-Theres; Vogel, Tanja; Lie, Dieter Chichung (Molecular Psychiatry, 2022)
The transcription factor FOXG1 serves pleiotropic functions in brain development ranging from the regulation of precursor proliferation to the control of cortical circuit formation. Loss-of-function mutations and duplications of FOXG1 are associated with neurodevelopmental disorders in humans illustrating the importance of FOXG1 dosage for brain development. Aberrant FOXG1 dosage has been found to disrupt the balanced activity of glutamatergic and GABAergic neurons, but the underlying mechanisms are not fully understood. We report that FOXG1 is expressed in the main adult neurogenic niches in mice, i.e. the hippocampal dentate gyrus and the subependymal zone/olfactory bulb system, where neurogenesis of glutamatergic and GABAergic neurons persists into adulthood. These niches displayed differential vulnerability to increased FOXG1 dosage: high FOXG1 levels severely compromised survival and glutamatergic dentate granule neuron fate acquisition in the hippocampal neurogenic niche, but left neurogenesis of GABAergic neurons in the subependymal zone/olfactory bulb system unaffected. Comparative transcriptomic analyses revealed a significantly higher expression of the apoptosis-linked nuclear receptor Nr4a1 in FOXG1-overexpressing hippocampal neural precursors. Strikingly, pharmacological interference with NR4A1 function rescued FOXG1-dependent death of hippocampal progenitors. Our results reveal differential vulnerability of neuronal subtypes to increased FOXG1 dosage and suggest that activity of a FOXG1/NR4A1 axis contributes to such subtype-specific response.
CRIS-Team WoS Importer:2022-04-08

Disproportional decrease in office blood pressure compared with 24-hour ambulatory blood pressure with antihypertensive treatment: dependency on pretreatment blood pressure levels - Schmieder, Roland; Schmidt, Stefan; Riemer, Thomas; Dechend, Ralf; Hagedorn, Ina; Senges, Jochen; Messerli, Franz H.; Zeymer, Uwe (Hypertension, 2014)
The long-term relationship between 24-hour ambulatory blood pressure (ABP) and office BP in patients on therapy is not well documented. From a registry we included all patients in whom antihypertensive therapy needed to be uptitrated. Drug treatment included the direct renin inhibitor aliskiren or an angiotensin-converting enzyme inhibitor/angiotensin receptor blocker or drugs not blocking the renin-angiotensin system, alone or on top of an existing drug regimen. In all patients, office BP and 24-hour ABP were obtained at baseline and after 1 year with validated devices. In the study population of 2722 patients, there was a good correlation between the change in office BP and 24-hour ABP (systolic: r=0.39; P<0.001; diastolic: r=0.34; P<0.001). However, the numeric decrease in office BP did not correspond to the decrease in ABP in a 1:1 fashion, for example, a decrease of 10, 20, and 30 mm Hg corresponded to a decrease of ?7.2, 10.5, and 13.9 mm Hg in systolic ABP, respectively. The disproportionally greater decrease in systolic office BP compared with ABP was dependent on the level of the pretreatment BP, which was consistently higher for office BP than ABP. The white coat effect (difference between office BP and ABP) was on average 10/5 mm Hg lower 1 year after intensifying treatment and the magnitude of that was also dependent on pretreatment BP. There was a disproportionally greater decrease in systolic office BP than in ABP, which for both office BP and ABP seemed to depend on the pretreatment BP level.
EVALuna2:3733

Disrupted SOX10 function causes spongiform neurodegeneration in gray tremor mice - Anderson, Sarah R.; Lee, Inyoul; Ebeling, Christine; Stephenson, Dennis A.; Schweitzer, Kelsey M.; Baxter, David; Moon, Tara M.; Lapierre, Sarah; Jaques, Benjamin; Silvius, Derek; Wegner, Michael; Hood, Leroy E.; et al. (Mammalian Genome, 2015)
Mice homozygous for the gray tremor (gt) mutation have a pleiotropic phenotype that includes pigmentation defects, megacolon, whole body tremors, sporadic seizures, hypo- and dys-myelination of the central nervous system (CNS) and peripheral nervous system, vacuolation of the CNS, and early death. Vacuolation similar to that caused by prions was originally reported to be transmissible, but subsequent studies showed the inherited disease was not infectious. The gt mutation mapped to distal mouse chromosome 15, to the same region as Sox10, which encodes a transcription factor with essential roles in neural crest survival and differentiation. As dominant mutations in mouse or human SOX10 cause white spotting and intestinal aganglionosis, we screened the Sox10 coding region for mutations in gt/gt DNA. An adenosine to guanine transversion was identified in exon 2 that changes a highly conserved glutamic acid residue in the SOX10 DNA binding domain to glycine. This mutant allele was not seen in wildtype mice, including the related GT/Le strain, and failed to complement a Sox10 null allele. Gene expression analysis revealed significant down-regulation of genes involved in myelin lipid biosynthesis pathways in gt/gt brains. Knockout mice for some of these genes develop CNS vacuolation and/or myelination defects, suggesting that their down-regulation may contribute to these phenotypes in gt mutants and could underlie the neurological phenotypes associated with peripheral demyelinating neuropathy-central dysmyelinating leukodystrophy-Waardenburg syndrome-Hirschsprung disease, caused by mutations in human SOX10.
EVALuna2:4982

Disruption of a Structurally Important Extracellular Element in the Glycine Receptor Leads to Decreased Synaptic Integration and Signaling Resulting in Severe Startle Disease - Schaefer, Natascha; Berger, Alexandra; van Brederode, Johannes; Zheng, Fang; Zhang, Yan; Leacock, Sophie; Littau, Laura; Jablonka, Sibylle; Malhotra, Sony; Topf, Maya; Winter, Friederike; Davydova, Daria; et al. (The Journal of Neuroscience, 2017)
Functional impairments or trafficking defects of inhibitory glycine receptors (GlyRs) have been linked to human hyperekplexia/startle disease and autism spectrum disorders. We found that a lack of synaptic integration of GlyRs, together with disrupted receptor function, is responsible for a lethal startle phenotype in a novel spontaneous mouse mutantshaky, caused by a missense mutation, Q177K, located in the extracellular β8-β9 loop of the GlyR α1 subunit. Recently, structural data provided evidence that the flexibility of the β8-β9 loop is crucial for conformational transitions during opening and closing of the ion channel and represents a novel allosteric binding site in Cys-loop receptors. We identified the underlying neuropathological mechanisms in male and femaleshakymice through a combination of protein biochemistry, immunocytochemistry, and bothin vivoand invitroelectrophysiology. Increased expression of the mutant GlyR α1Q177Ksubunitin vivowas not sufficient to compensate for a decrease in synaptic integration of α1Q177Kβ GlyRs. The remaining synaptic heteromeric α1Q177Kβ GlyRs had decreased current amplitudes with significantly faster decay times. This functional disruption reveals an important role for the GlyR α1 subunit β8-β9 loop in initiating rearrangements within the extracellular-transmembrane GlyR interface and that this structural element is vital for inhibitory GlyR function, signaling, and synaptic clustering.SIGNIFICANCE STATEMENTGlyR dysfunction underlies neuromotor deficits in startle disease and autism spectrum disorders. We describe an extracellular GlyR α1 subunit mutation (Q177K) in a novel mouse startle disease mutantshakyStructural data suggest that during signal transduction, large transitions of the β8-β9 loop occur in response to neurotransmitter binding. Disruption of the β8-β9 loop by the Q177K mutation results in a disruption of hydrogen bonds between Q177 and the ligand-binding residue R65. Functionally, the Q177K change resulted in decreased current amplitudes, altered desensitization decay time constants, and reduced GlyR clustering and synaptic strength. The GlyR β8-β9 loop is therefore an essential regulator of conformational rearrangements during ion channel opening and closing.
EVALuna2:33340

Dissimilar Appearances Are Deceptive-Common microRNAs and Therapeutic Strategies in Liver Cancer and Melanoma - Linck-Paulus, Lisa; Hellerbrand, Claus; Boßerhoff, Anja Katrin; Dietrich, Peter (Cells, 2020)
: In this review, we summarize the current knowledge on miRNAs as therapeutic targets in two cancer types that were frequently described to be driven by miRNAs-melanoma and hepatocellular carcinoma (HCC). By focusing on common microRNAs and associated pathways in these-at first sight-dissimilar cancer types, we aim at revealing similar molecular mechanisms that are evolved in microRNA-biology to drive cancer progression. Thereby, we also want to outlay potential novel therapeutic strategies. After providing a brief introduction to general miRNA biology and basic information about HCC and melanoma, this review depicts prominent examples of potent oncomiRs and tumor-suppressor miRNAs, which have been proven to drive diverse cancer types including melanoma and HCC. To develop and apply miRNA-based therapeutics for cancer treatment in the future, it is essential to understand how miRNA dysregulation evolves during malignant transformation. Therefore, we highlight important aspects such as genetic alterations, miRNA editing and transcriptional regulation based on concrete examples. Furthermore, we expand our illustration by focusing on miRNA-associated proteins as well as other regulators of miRNAs which could also provide therapeutic targets. Finally, design and delivery strategies of miRNA-associated therapeutic agents as well as potential drawbacks are discussed to address the question of how miRNAs might contribute to cancer therapy in the future.
EVALuna2:212285

Distinct forebrain regions define a dichotomous astrocytic profile in multiple system atrophy - Schneider, Yanni; Gauer, Carina; Andert, Marie; Hoffmann, Alana; Riemenschneider, M. J.; Krebs, W.; Chalmers, Nicholas; Lötzsch, C.; Naumann, Ulrike; Xiang, Wei; Rothhammer, Veit; Beckervordersandforth, Ruth; et al. (Acta Neuropathologica Communications, 2024)
The growing recognition of a dichotomous role of astrocytes in neurodegenerative processes has heightened the need for unraveling distinct astrocytic subtypes in neurological disorders. In multiple system atrophy (MSA), a rare, rapidly progressing atypical Parkinsonian disease characterized by increased astrocyte reactivity. However the specific contribution of astrocyte subtypes to neuropathology remains elusive. Hence, we first set out to profile glial fibrillary acidic protein levels in astrocytes across the human post mortem motor cortex, putamen, and substantia nigra of MSA patients and observed an overall profound astrocytic response. Matching the post mortem human findings, a similar astrocytic phenotype was present in a transgenic MSA mouse model. Notably, MSA mice exhibited a decreased expression of the glutamate transporter 1 and glutamate aspartate transporter in the basal ganglia, but not the motor cortex. We developed an optimized astrocyte isolation protocol based on magnetic-activated cell sorting via ATPase Na+/K+ transporting subunit beta 2 and profiled the transcriptomic landscape of striatal and cortical astrocytes in transgenic MSA mice. The gene expression profile of astrocytes in the motor cortex displayed an anti-inflammatory signature with increased oligodendroglial and pro-myelinogenic expression pattern. In contrast, striatal astrocytes were defined by elevated pro-inflammatory transcripts accompanied by dysregulated genes involved in homeostatic functions for lipid and calcium metabolism. These findings provide new insights into a region-dependent, dichotomous astrocytic response—potentially beneficial in the cortex and harmful in the striatum—in MSA suggesting a differential role of astrocytes in MSA-related neurodegenerative processes.
CRIS-Team Scopus Importer:2024-01-12

Distribution of Aldh1L1-CreERT2 Recombination in Astrocytes Versus Neural Stem Cells in the Neurogenic Niches of the Adult Mouse Brain - Beyer, Felix; Lüdje, Wichard; Karpf, Julian; Saher, Gesine; Beckervordersandforth, Ruth (Frontiers in Neuroscience, 2021)
In the adult central nervous system, neural stem cells (NSCs) reside in two discrete niches: the subependymal zone (SEZ) of the lateral ventricle and the subgranular zone (SGZ) of the dentate gyrus (DG). Here, NSCs represent a population of highly specialized astrocytes that are able to proliferate and give rise to neuronal and glial progeny. This process, termed adult neurogenesis, is extrinsically regulated by other niche cells such as non-stem cell astrocytes. Studying these non-stem cell niche astrocytes and their role during adult neuro- and gliogenesis has been hampered by the lack of genetic tools to discriminate between transcriptionally similar NSCs and niche astrocytes. Recently, Aldh1L1 has been shown to be a pan-astrocyte marker and that its promoter can be used to specifically target astrocytes using the Cre-loxP system. In this study we explored whether the recently described Aldh1L1-CreERT2 mouse line (Winchenbach et al., 2016) can serve to specifically target niche astrocytes without inducing recombination in NSCs in adult neurogenic niches. Using short- and long-term tamoxifen protocols we revealed high recombination efficiency and specificity in non-stem cell astrocytes and little to no recombination in NSCs of the adult DG. However, in the SEZ we observed recombination in ependymal cells, astrocytes, and NSCs, the latter giving rise to neuronal progeny of the rostral migratory stream and olfactory bulb. Thus, we recommend the here described Aldh1L1-CreERT2 mouse line for predominantly studying the functions of non-stem cell astrocytes in the DG under physiological and pathological conditions.
CRIS-Team Scopus Importer:2021-10-01
Keywords: Aldh1L1; Aldh1L1-CreER; astrocytes; dentate gyrus; neural stem cells; neurogenic niche; subependymal zone

Disturbed neuronal ER-Golgi sorting of unassembled glycine receptors suggests altered subcellular processing is a cause of human hyperekplexia - Schaefer, Natascha; Kluck, Christoph; Price, Kerry L.; Meiselbach, Heike; Vornberger, Nadine; Schwarzinger, Stephan; Hartmann, Stephanie; Langlhofer, Georg; Schulz, Solveig; Schlegel, Nadja; Brockmann, Knut; Lynch, Bryan; et al. (The Journal of Neuroscience, 2015)
Recent studies on the pathogenic mechanisms of recessive hyperekplexia indicate disturbances in glycine receptor (GlyR) ?1 biogenesis. Here, we examine the properties of a range of novel glycine receptor mutants identified in human hyperekplexia patients using expression in transfected cell lines and primary neurons. All of the novel mutants localized in the large extracellular domain of the GlyR ?1 have reduced cell surface expression with a high proportion of receptors being retained in the ER, although there is forward trafficking of glycosylated subpopulations into the ER-Golgi intermediate compartment and cis-Golgi compartment. CD spectroscopy revealed that the mutant receptors have proportions of secondary structural elements similar to wild-type receptors. Two mutants in loop B (G160R, T162M) were functional, but none of those in loop D/?2-3 were. One nonfunctional truncated mutant (R316X) could be rescued by coexpression with the lacking C-terminal domain. We conclude that a proportion of GlyR ?1 mutants can be transported to the plasma membrane but do not necessarily form functional ion channels. We suggest that loop D/?2-3 is an important determinant for GlyR trafficking and functionality, whereas alterations to loop B alter agonist potencies, indicating that residues here are critical elements in ligand binding.
EVALuna2:4704

DNA binding by Corynebacterium glutamicum TetR-type transcription regulator AmtR - Muhl, Daniela; Jeßberger, Nadja; Hasselt, Kristin; Jardin, Christophe; Sticht, Heinrich; Burkovski, Andreas (Bmc Molecular Biology, 2009)

DNMT targets MiRacle torching TORCh - Dietrich, Peter; Boßerhoff, Anja Katrin (Pigment Cell & Melanoma Research, 2016)
EVALuna2:4735

Does Metal Ion Complexation Make Radical Clocks Run Fast? - Horn, Anselm; Clark, Timothy (Journal of the American Chemical Society, 2003)
Ab initio molecular orbital and density functional calculations at the CBS-RAD(QCISD,B3-LYP) level for Li + and at B3LYP for Na +, K +, Cu +, and Ag + reveal that the barrier to ring-closure of the 1 -hexen-6-yl ("Δ(5)-hexenyl") radical to the cyclopentylmethyl radical, a so-called radical clock reaction, is decreased very significantly by complexation of the double bond to metal cations. This barrier lowering should occur on complexation with many metal ions, as shown by calculations on all of the monovalent ions listed above. Additional density functional calculations including explicit solvation of the model system complexed to the lithium ion with tetrahydrofuran suggest that the effect found is not limited to the gas phase but may also be significant in experimental radical clock reactions in solution, even for lithium.
UnivIS-Import:2015-03-09:Pub.2003.forsch.sonder.sfb583.doesme

Dual Inhibition of mTORC1/2 Reduces Migration of Cholangiocarcinoma Cells by Regulation of Matrixmetalloproteinases - Joechle, Katharina; Jumaa, Huda; Thriene, Kerstin; Hellerbrand, Claus; Kulemann, Birte; Fichtner-Feigl, Stefan; Lang, Sven A.; Guenzle, Jessica (Frontiers in Cell and Developmental Biology, 2022)
Cholangiocarcinoma (CCA) is a rare but highly aggressive tumor entity for which systemic therapies only showed limited efficacy so far. As OSI-027—a dual kinase inhibitor targeting both mTOR complexes, mTORC1 and mTORC2 - showed improved anti-cancer effects, we sought to evaluate its impact on the migratory and metastatic capacity of CCA cells in vitro. We found that treatment with OSI-027 leads to reduced cell mobility and migration as well as a reduced surviving fraction in colony-forming ability. While neither cell viability nor proliferation rate was affected, OSI-027 decreased the expression of MMP2 and MMP9. Moreover, survival as well as anti-apoptotic signaling was impaired upon the use of OSI-027 as determined by AKT and MAPK blotting. Dual targeting of mTORC1/2 might therefore be a viable option for anti-neoplastic therapy in CCA.
CRIS-Team Scopus Importer:2022-02-11
Keywords: cholangiocarcinoma; invasion; matrix metalloproteinases; migration; MTORC1/2

Dual regulation of somatostatin receptor subtype 1 gene expression by pit-1 in anterior pipuitary GH3 cells - Wegner, Michael; et al. (Molecular Endocrinology, 2000)
UnivIS-Import:2015-03-05:Pub.2000.med.IB.LPCIPDBI.dualre

Dual specificity phosphatase 15 regulates Erk activation in Schwann cells - Rodriguez-Molina, Jose F.; Lopez-Anido, Camila; Ma, Ki H.; Zhang, Chongyu; Olson, Tyler; Weider, Matthias; Muth, Katharina; Svaren, John (Journal of Neurochemistry, 2017)
Schwann cells and oligodendrocytes are the myelinating cells of the peripheral and central nervous system, respectively. Despite having different myelin components and different transcription factors driving their terminal differentiation there are shared molecular mechanisms between the two. Sox10 is one common transcription factor required for several steps in development of myelinating glia. However, other factors are divergent as Schwann cells need the transcription factor early growth response 2/Krox20 and oligodendrocytes require Myrf. Likewise, some signaling pathways, like the Erk1/2 kinases, are necessary in both cell types for proper myelination. Nonetheless, the molecular mechanisms that control this shared signaling pathway in myelinating cells remain only partially characterized. The hypothesis of this study is that signaling pathways that are similarly regulated in both Schwann cells and oligodendrocytes play central roles in coordinating the differentiation of myelinating glia. To address this hypothesis, we have used genome-wide binding data to identify a relatively small set of genes that are similarly regulated by Sox10 in myelinating glia. We chose one such gene encoding Dual specificity phosphatase 15 (Dusp15) for further analysis in Schwann cell signaling. RNA interference and gene deletion by genome editing in cultured RT4 and primary Schwann cells showed Dusp15 is necessary for full activation of Erk1/2 phosphorylation. In addition, we show that Dusp15 represses expression of several myelin genes, including myelin basic protein. The data shown here support a mechanism by which early growth response 2 activates myelin genes, but also induces a negative feedback loop through Dusp15 to limit over-expression of myelin genes.
EVALuna2:33487

Dynamic regulatory interaction between cytomegalovirus major tegument protein pp65 and protein kinase pUL97 in intracellular compartments, dense bodies and virions - König, Patrick; Buescher, Nicoie; Steingruber, Mirjam; Socher, Eileen; Sticht, Heinrich; Tenzer, Stefan; Plachter, Bodo; Marschall, Manfred (Journal of General Virology, 2017)
Human cytomegalovirus (HCMV) is a ubiquitous pathogen of considerable clinical importance. Understanding the processes that are important for viral replication is essential for the development of therapeutic strategies against HCMV infection. The HCMV-encoded protein kinase pUL97 is an important multifunctional regulator of viral replication. Several viral and cellular proteins are phosphorylated by pUL97. The phosphoprotein pp65 is one important substrate of pUL97. It is the most abundant tegument protein of HCMV virions, mediating the upload of other virion constituents and contributing to particle integrity. Further to that, it interferes with host innate immune defences, thereby enabling efficient viral replication. By applying different approaches, we characterized the pp65-pUL97 interaction in various compartments. Specifically, the pUL97 interaction domain of pp65 was defined (282-415). A putative cyclin bridge that enhances pUL97-pp65 interaction was identified. The impact of pUL97 mutation on virion and dense body morphogenesis was addressed using pUL97 mutant viruses. Alterations in the proteome of viral particles were seen, especially with mutant viruses expressing cytoplasmic variants of pUL97. On the basis of these data we postulate a so far poorly recognized functional relationship between pp65 and pUL97, and present a refined model of pp65-pUL97 interaction.
EVALuna2:33718

Dynamic, transient, and robust increase in the innervation of the inflamed mucosa in inflammatory bowel diseases - Gonzalez Acera, Miguel; Bubeck, Marvin; Mascia, Fabrizio; Diemand, Leonard; Sturm, Gregor; Kuehl, Anja A.; Atreya, Raja; Lie, Dieter Chichung; Neurath, Markus; Schumann, Michael; Klose, Christoph S. N.; Trajanoski, Zlatko; et al. (Cells, 2021)
Inflammatory bowel diseases (IBD) are characterized by chronic dysregulation of immune homeostasis, epithelial demise, immune cell activation, and microbial translocation. Each of these processes leads to proinflammatory changes via the release of cytokines, damage-associated molecular patterns (DAMPs), and pathogen-associated molecular patterns (PAMPs), respectively. The impact of these noxious agents on the survival and function of the enteric nervous system (ENS) is poorly understood. Here, we show that in contrast to an expected decrease, experimental as well as clinical colitis causes an increase in the transcript levels of enteric neuronal and glial genes. Immunostaining revealed an elevated neuronal innervation of the inflamed regions of the gut mucosa. The increase was seen in models with overt damage to epithelial cells and models of T cell-induced colitis. Transcriptomic data from treatment naïve pediatric IBD patients also confirmed the increase in the neuroglial genes and were replicated on an independent adult IBD dataset. This induction in the neuroglial genes was transient as levels returned to normal upon the induction of remission in both mouse models as well as colitis patients. Our data highlight the dynamic and robust nature of the enteric nervous system in colitis and open novel questions on its regulation.
CRIS-Team Scopus Importer:2021-10-08
Keywords: Crohn’s disease; Enteric nervous system; Inflammatory bowel diseases; Neurogenesis; Ulcerative colitis

DYNC2LI1 mutations broaden the clinical spectrum of dynein-2 defects - Keßler, Kristin; Wunderlich, Ina; Uebe, Steffen; Falk, Nathalie; Gießl, Andreas; Brandstätter, Johann Helmut; Popp, Bernt; Klinger, Patricia; Ekici, Arif Bülent; Sticht, Heinrich; Dörr, Helmuth-Günther; Reis, André; et al. (Scientific Reports, 2015)
Skeletal ciliopathies are a heterogeneous group of autosomal recessive osteochondrodysplasias caused by defects in formation, maintenance and function of the primary cilium. Mutations in the underlying genes affect the molecular motors, intraflagellar transport complexes (IFT), or the basal body. The more severe phenotypes are caused by defects of genes of the dynein-2 complex, where mutations in DYNC2H1, WDR34 and WDR60 have been identified. In a patient with a Jeune-like phenotype we performed exome sequencing and identified compound heterozygous missense and nonsense mutations in DYNC2LI1 segregating with the phenotype. DYNC2LI1 is ubiquitously expressed and interacts with DYNC2H1 to form the dynein-2 complex important for retrograde IFT. Using DYNC2LI1 siRNA knockdown in fibroblasts we identified a significantly reduced cilia length proposed to affect cilia function. In addition, depletion of DYNC2LI1 induced altered cilia morphology with broadened ciliary tips and accumulation of IFT-B complex proteins in accordance with retrograde IFT defects. Our results expand the clinical spectrum of ciliopathies caused by defects of the dynein-2 complex.
EVALuna2:9281

Dysfunction of spatacsin leads to axonal pathology in SPG11-linked hereditary spastic paraplegia - Perez-Branguli, Francesc; Mishra, Himanshu Kumar; Prots, Iryna; Havlicek, Steven; Kohl, Zacharias; Saul, Domenica; Rummel, Christine; Dorca-Arevalo, Jonatan; Regensburger, Martin; Graef, Daniela; Sock, Elisabeth; Blasi, Juan; et al. (Human Molecular Genetics, 2014)
Hereditary spastic paraplegias are a group of inherited motor neuron diseases characterized by progressive paraparesis and spasticity. Mutations in the spastic paraplegia gene SPG11, encoding spatacsin, cause an autosomal-recessive disease trait; however, the precise knowledge about the role of spatacsin in neurons is very limited. We for the first time analyzed the expression and function of spatacsin in human forebrain neurons derived from human pluripotent stem cells including lines from two SPG11 patients and two controls. SPG11 patients'-derived neurons exhibited downregulation of specific axonal-related genes, decreased neurite complexity and accumulation of membranous bodies within axonal processes. Altogether, these data point towards axonal pathologies in human neurons with SPG11 mutations. To further corroborate spatacsin function, we investigated human pluripotent stem cell-derived neurons and mouse cortical neurons. In these cells, spatacsin was located in axons and dendrites. It colocalized with cytoskeletal and synaptic vesicle (SV) markers and was present in synaptosomes. Knockdown of spatacsin in mouse cortical neurons evidenced that the loss of function of spatacsin leads to axonal instability by downregulation of acetylated tubulin. Finally, time-lapse assays performed in SPG11 patients'-derived neurons and spatacsin-silenced mouse neurons highlighted a reduction in the anterograde vesicle trafficking indicative of impaired axonal transport. By employing SPG11 patient-derived forebrain neurons and mouse cortical neurons, this study provides the first evidence that SPG11 is implicated in axonal maintenance and cargo trafficking. Understanding the cellular functions of spatacsin will allow deciphering mechanisms of motor cortex dysfunction in autosomal-recessive hereditary spastic paraplegia.
EVALuna2:4956

Effect of aliskiren on vascular remodelling in small retinal circulation - Jumar, Agnes; Ott, Christian; Kistner, Iris; Friedrich, Stefanie; Schmidt, Stefan; Harazny, Joanna M.; Schmieder, Roland (Journal of Hypertension, 2015)
In hypertension, changes in small arterial structure are characterized by an increased wall-to-lumen ratio (WLR). These adaptive processes are modulated by the rennin-angiotensin system. It is unclear whether direct renin inhibitors exert protective effects on small arteries in hypertensive patients.In this double-blind, randomized, placebo-controlled study (http://www.clinicaltrials.gov: NCT01318395), 114 patients with primary hypertension were randomized to additional therapy with either placebo or aliskiren 300 mg for 8 weeks after 4 weeks of standardized open-label treatment with valsartan 320 mg (run-in phase). Parameter of arteriolar remodelling was WLR of retinal arterioles (80 - 140 ?m) assessed noninvasively and in vivo by scanning laser Doppler flowmetry (Heidelberg Engineering, Germany). In addition, pulse wave analysis (SphygmoCor, AtCor Medical, Australia) and pulse pressure (PP) amplification were determined.In the whole study population, no clear effect of additional therapy with aliskiren on vascular parameters was documented. When analyses were restricted to patients with vascular remodelling, defined by a median of WLR more than 0.3326 (n = 57), WLR was reduced after 8 weeks by the treatment with aliskiren compared with placebo (-0.044 ± 0.07 versus 0.0043 ± 0.07, P = 0.015). Consistently, after 8 weeks of on-top treatment with aliskiren, there was an improvement of PP amplification compared with placebo (0.025 ± 0.07 versus -0.034 ± 0.08, P = 0.013), indicative of less stiff arteries in the peripheral circulation.Thus, our data indicate that treatment with aliskiren, given on top of valsartan therapy, improves altered vascular remodelling in hypertensive patients.
EVALuna2:3799

Effect of Ions and Sequence Variants on the Antagonist Binding Properties of the Histamine H1 Receptor - Conrad, Marcus; Söldner, Christian; Sticht, Heinrich (International Journal of Molecular Sciences, 2022)
The histamine H1 receptor (H1R) is a G protein-coupled receptor (GPCR) and represents a main target in the treatment of allergic reactions as well as inflammatory reactions and depressions. Although the overall effect of antagonists on H1 function has been extensively investigated, rather little is known about the potential modulatory effect of ions or sequence variants on antagonist binding. We investigated the dynamics of a phosphate ion present in the crystal structure and of a sodium ion, for which we determined the position in the allosteric pocket by metadynamics simulations. Both types of ions exhibit significant dynamics within their binding site; however, some key contacts remain stable over the simulation time, which might be exploited to develop more potent drugs targeting these sites. The dynamics of the ions is almost unaffected by the presence or absence of doxepin, as also reflected in their small effect (less than 1 kcal·mol−1 ) on doxepin binding affinity. We also examined the effect of four H1R sequence variants observed in the human population on doxepin binding. These variants cause a reduction in doxepin affinity of up to 2.5 kcal·mol−1, indicating that personalized medical treatments that take into account individual mutation patterns could increase precision in the dosage of GPCR-targeting drugs.
CRIS-Team Scopus Importer:2022-02-04
Keywords: Allosteric modulator; Doxepin; G protein-coupled receptors (GPCRs); Metadynamics; Molecular dynamics simulations; Phosphate; Receptor-ligand interactions; Sequence variants; Sodium binding; Sodium pocket

Effect of melanoma cells on proliferation and migration of activated hepatic stellate cells in vitro - Meyer, Theresa; Koch, Andreas; Ebert, Eva-Vanessa; Czech, Barbara; Mueller, Martina; Boßerhoff, Anja Katrin; Lang, Sven Arke; Hellerbrand, Claus (Pathology Research and Practice, 2017)
Melanoma is a highly aggressive tumor of the skin. The clinical outcome is determined by the presence or absence of metastases, and the liver is a common site of distant metastases. Hepatic metastasis is causing activation of hepatic stellate cells (HSC), which form the stroma of hepatic metastases and are increasingly recognized as a crucial component of the pro- metastatic liver microenvironment. Most studies have focused on the effects of HSC on (metastasizing) tumor cells. Here, we aimed to analyze functional in vitro effects of conditioned medium (CM) of twelve different human melanoma cell lines on LX2 cells and HSC(htert) cells, two well established human activated HSC cell lines. CM from melanoma cells significantly induced HSC proliferation and acted as chemoattractant for HSC in Boyden chamber assays. The CM effects significantly varied between different HSC as well as melanoma cells. Interestingly, CM from melanoma cell lines derived from melanoma metastases (WM239A, WM9, WM1158, WM1232, 451Lu and 1205Lu) had a stronger effect on proliferation of HSC(htert) cells than CM derived from primary melanoma tumors (SbCl2, WM3211, WM35, WM278, WM1366 and WM793). Moreover, we observed a significant correlation between the chemoattractive effects of CM from the different melanoma cells on HSC(htert) and LX2 cells. In contrast, the melanoma CM effects on the proliferation of the two HSC lines did not show a significant correlation. In summary, our data indicate that melanoma cells metastasizing to the liver have the potential to attract HSC and to induce HSC proliferation, respectively. Still, it appears that melanoma effects on HSC migration and proliferation are mediated via different soluble factors indicating the complexity of melanoma-HSC interaction. Furthermore, the intensity of at least some functional effects varies between different human tumor cells and HSC which may point to mechanisms explaining diverse hepatic metastasis in melanoma patients.
EVALuna2:4750

Effect of the hop compound xanthohumol on lipoteichic acids-induced inflammatory processes in healthy humans - Jung, Finn; Staltner, Raphaela; Tahir, Ammar; Baumann, Anja; Burger, Katharina; Halilbasic, Emina; Hellerbrand, Claus; Bergheim, Ina (Special Issue of Alcoholism: Clinical and Experimental Research, 2022)
CRIS-Team WoS Importer:2022-09-23

Effect of the SH3-SH2 domain linker sequence on the structure of Hck kinase - Meiselbach, Heike; Sticht, Heinrich (Journal of Molecular Modeling, 2011)
The coordination of activity in biological systems requires the existence of different signal transduction pathways that interact with one another and must be precisely regulated. The Src-family tyrosine kinases, which are found in many signaling pathways, differ in their physiological function despite their high overall structural similarity. In this context, the differences in the SH3-SH2 domain linkers might play a role for differential regulation, but the structural consequences of linker sequence remain poorly understood. We have therefore performed comparative molecular dynamics simulations of wildtype Hck and of a mutant Hck in which the SH3-SH2 domain linker is replaced by the corresponding sequence from the homologous kinase Lck. These simulations reveal that linker replacement not only affects the orientation of the SH3 domain itself, but also leads to an alternative conformation of the activation segment in the Hck kinase domain. The sequence of the SH3-SH2 domain linker thus exerts a remote effect on the active site geometry and might therefore play a role in modulating the structure of the inactive kinase or in fine-tuning the activation process itself.
EVALuna2:26262

Effects of Cold Atmospheric Plasma (CAP) on ß-Defensins, Inflammatory Cytokines, and Apoptosis-Related Molecules in Keratinocytes In Vitro and In Vivo - Arndt, Stephanie; Landthaler, Michael; Zimmermann, Julia L.; Unger, Petra; Wacker, Eva; Shimizu, Tetsuji; Li, Yang-Fang; Morfill, Gregor E.; Boßerhoff, Anja Katrin; Karrer, Sigrid (PLoS ONE, 2015)
Cold atmospheric plasma (CAP) has been gaining increasing interest as a new approach for the treatment of skin diseases or wounds. Although this approach has demonstrated promising antibacterial activity, its exact mechanism of action remains unclear. This study explored in vitro and in vivo whether CAP influences gene expression and molecular mechanisms in keratinocytes. Our results revealed that a 2 min CAP treatment using the MicroPlaSter ß in analogy to the performed clinical studies for wound treatment induces expression of IL-8, TGF-ß1, and TGF-ß2. In vitro and in vivo assays indicated that keratinocyte proliferation, migration, and apoptotic mechanisms were not affected by the CAP treatment under the applied conditions. Further, we observed that antimicrobial peptides of the ß-defensin family are upregulated after CAP treatment. In summary, our results suggest that a 2 min application of CAP induces gene expression of key regulators important for inflammation and wound healing without causing proliferation, migration or cell death in keratinocytes. The induction of ß-defensins in keratinocytes describes an absolutely new plasma strategy. Activation of antimicrobial peptides supports the well-known antibacterial effect of CAP treatment, whereas the mechanism of ß-defensin activation by CAP is not investigated so far.
EVALuna2:4706

Effects of saxagliptin on early microvascular changes in patients with type 2 diabetes - Ott, Christian; Raff, Ulrike; Schmidt, Stefan; Kistner, Iris; Friedrich, Stefanie; Bramlage, Peter; Harazny, Joanna M.; Schmieder, Roland (Cardiovascular Diabetology, 2014)
Patients with diabetes mellitus are at increased risk for microvascular complications. Early changes in microcirculation are characterized by hyperperfusion (e.g. in the retina and kidney) and increased pulse wave reflection leading to increased aortic pressure. We investigated the effects of the DPP-4-inhibitor saxagliptin on early retinal microvascular changes.In this double-blind, controlled, cross-over trial 50 patients (without clinical signs of microvascular alterations) with type-2 diabetes (mean duration of 4 years) were randomized to receive placebo or 5 mg saxagliptin for 6 weeks. Retinal arteriolar structure and retinal capillary flow (RCF) at baseline and during flicker-light exposure was assessed by scanning laser Doppler flowmetry. Central hemodynamics were assessed by pulse wave analysis.Postprandial blood glucose (9.27 ± 0.4 versus 10.1 ± 0.4 mmol/L; p = 0.001) and HbA1c (6.84 ± 0.15 (51 ± 1.6) versus 7.10 ± 0.17% (54 ± 1.9 mmol/mol); p < 0.001) were significantly reduced with saxagliptin treatment compared to placebo. RCF was significantly reduced after treatment with saxagliptin (288 ± 13.2 versus 314 ± 14.1 AU; p = 0.033). This was most pronounced in a subgroup of patients (n = 32) with a fall in postprandial blood glucose (280 ± 12.1 versus 314 ± 16.6 AU; p = 0.011). No significant changes in RCF were seen during flicker-light exposure between placebo and saxagliptin, but the vasodilatory capacity increased two-fold with saxagliptin treatment. Central augmentation pressure tended to be lower after treatment with saxagliptin (p = 0.094), and central systolic blood pressure was significantly reduced (119 ± 2.3 versus 124 ± 2.3 mmHg; p = 0.038).Our data suggest that treatment with saxagliptin for 6 weeks normalizes retinal capillary flow and improves central hemodynamics in type-2 diabetes.The study was registered at (ID: NCT01319357).
EVALuna2:3676

EFhd2/Swiprosin-1 is a common genetic determinator for sensation-seeking/low anxiety and alcohol addiction - Mielenz, Dirk; Reichel, Martin; Jia, T.; Quinlan, E. B.; Stöckl, Thomas; Mettang, M.; Zilske, Daniel; Kirmizi Alsan, Elif; Schoenberger, P.; Praetner, M.; Huber, Sabine; Amato, Davide; et al. (Molecular Psychiatry, 2017)
In many societies, the majority of adults regularly consume alcohol. However, only a small proportion develops alcohol addiction. Individuals at risk often show a high sensation-seeking/low-anxiety behavioural phenotype. Here we asked which role EF hand domain containing 2 (EFhd2; Swiprosin-1) plays in the control of alcohol addiction-associated behaviours. EFhd2 knockout (KO) mice drink more alcohol than controls and spontaneously escalate their consumption. This coincided with a sensation-seeking and low-anxiety phenotype. A reversal of the behavioural phenotype with β-carboline, an anxiogenic inverse benzodiazepine receptor agonist, normalized alcohol preference in EFhd2 KO mice, demonstrating an EFhd2-driven relationship between personality traits and alcohol preference. These findings were confirmed in a human sample where we observed a positive association of the EFhd2 single-nucleotide polymorphism rs112146896 with lifetime drinking and a negative association with anxiety in healthy adolescents. The lack of EFhd2 reduced extracellular dopamine levels in the brain, but enhanced responses to alcohol. In confirmation, gene expression analysis revealed reduced tyrosine hydroxylase expression and the regulation of genes involved in cortex development, Eomes and Pax6, in EFhd2 KO cortices. These findings were corroborated in Xenopus tadpoles by EFhd2 knockdown. Magnetic resonance imaging (MRI) in mice showed that a lack of EFhd2 reduces cortical volume in adults. Moreover, human MRI confirmed the negative association between lifetime alcohol drinking and superior frontal gyrus volume. We propose that EFhd2 is a conserved resilience factor against alcohol consumption and its escalation, working through Pax6/Eomes. Reduced EFhd2 function induces high-risk personality traits of sensation-seeking/low anxiety associated with enhanced alcohol consumption, which may be related to cortex function.
EVALuna2:4036

EFHD2/SWIPROSIN-1 IS A CONSERVED RESILIENCE FACTOR AGAINST ALCOHOL DRINKING ESCALATION - Müller, Christian P.; Reichel, Martin; Jia, T.; Quinlan, E. B.; Schambony, Alexandra; Bäuerle, Tobias; Eulenburg, Volker; Lourdusamy, A.; Schumann, G.; Mielenz, Dirk (2018)
EVALuna2:35243

Egr2-guided histone H2B monoubiquitination is required for peripheral nervous system myelination - Wüst, Hannah; Wegener, Amelie; Fröb, Franziska; Hartwig, Anna; Wegwitz, Florian; Kari, Vijayalakshmi; Schimmel, Margit; Tamm, Ernst R.; Johnsen, Steven A.; Wegner, Michael; Sock, Elisabeth (Nucleic Acids Research, 2020)
Schwann cells are the nerve ensheathing cells of the peripheral nervous system. Absence, loss and malfunction of Schwann cells or their myelin sheaths lead to peripheral neuropathies such as Charcot-Marie-Tooth disease in humans. During Schwann cell development and myelination chromatin is dramatically modified. However, impact and functional relevance of these modifications are poorly understood. Here, we analyzed histone H2B monoubiquitination as one such chromatin modification by conditionally deleting the Rnf40 subunit of the responsible E3 ligase in mice. Rnf40-deficient Schwann cells were arrested immediately before myelination or generated abnormally thin, unstable myelin, resulting in a peripheral neuropathy characterized by hypomyelination and progressive axonal degeneration. By combining sequencing techniques with functional studies we show that H2B monoubiquitination does not influence global gene expression patterns, but instead ensures selective high expression of myelin and lipid biosynthesis genes and proper repression of immaturity genes. This requires the specific recruitment of the Rnf40-containing E3 ligase by Egr2, the central transcriptional regulator of peripheral myelination, to its target genes. Our study identifies histone ubiquitination as essential for Schwann cell myelination and unravels new disease-relevant links between chromatin modifications and transcription factors in the underlying regulatory network.
CRIS-Team Scopus Importer:2020-10-02

Eine übermäßige Phagozytose von Myelomzellen induziert Pyroptose in Myelom-assoziierten Makrophagen und beeinträchtigt die Wirksamkeit therapeutischer Antikörper - Flamann, Cindy; Biedermann, Alexander; Mougiakakos, D.; Bitterer, Katrin; Karg, K.; Bittenbring, J.; Büttner-Herold, Maike; Liebisch, G.; Leffler, M.; Lischer, Christopher; Eberhardt, Martin; Vera-Gonzales, J.; et al. (ONCOLOGY RESEARCH AND TREATMENT, 2022)
CRIS-Team WoS Importer:2022-11-18

Elevated in vivo levels of a single transcription factor directly convert satellite glia into oligodendrocyte-like cells - Weider, Matthias; Wegener, Amelie; Schmitt-Engel, Christian; Küspert, Melanie; Hillgaertner, Simone; Boesl, Michael R.; Hermans-Borgmeyer, Irm; Nait-Oumesmar, Brahim; Wegner, Michael (PLoS Genetics, 2015)
Oligodendrocytes are the myelinating glia of the central nervous system and ensure rapid saltatory conduction. Shortage or loss of these cells leads to severe malfunctions as observed in human leukodystrophies and multiple sclerosis, and their replenishment by reprogramming or cell conversion strategies is an important research aim. Using a transgenic approach we increased levels of the transcription factor Sox10 throughout the mouse embryo and thereby prompted Fabp7-positive glial cells in dorsal root ganglia of the peripheral nervous system to convert into cells with oligodendrocyte characteristics including myelin gene expression. These rarely studied and poorly characterized satellite glia did not go through a classic oligodendrocyte precursor cell stage. Instead, Sox10 directly induced key elements of the regulatory network of differentiating oligodendrocytes, including Olig2, Olig1, Nkx2.2 and Myrf. An upstream enhancer mediated the direct induction of the Olig2 gene. Unlike Sox10, Olig2 was not capable of generating oligodendrocyte-like cells in dorsal root ganglia. Our findings provide proof-of-concept that Sox10 can convert conducive cells into oligodendrocyte-like cells in vivo and delineates options for future therapeutic strategie
EVALuna2:4978

Elucidation of the phenotypic spectrum and genetic landscape in primary and secondary microcephaly - Boonsawat, P.; Joset, P.; Steindl, K.; Oneda, B.; Gogoll, L.; Azzarello-Burri, S.; Sheth, F.; Datar, C.; Verma, I.; Puri, R. Dua; Zollino, M.; Bachmann-Gagescu, R.; et al. (EUROPEAN JOURNAL OF HUMAN GENETICS, 2019)
CRIS-Team WoS Importer:2019-10-25

Elucidation of the phenotypic spectrum and genetic landscape in primary and secondary microcephaly - Boonsawat, Paranchai; Joset, Pascal; Steindl, Katharina; Oneda, Beatrice; Gogoll, Laura; Azzarello-Burri, Silvia; Sheth, Frenny; Datar, Chaitanya; Verma, Ishwar C.; Puri, Ratna Dua; Zollino, Marcella; Bachmann-Gagescu, Ruxandra; et al. (Genetics in Medicine, 2019)
Purpose: Microcephaly is a sign of many genetic conditions but has been rarely systematically evaluated. We therefore comprehensively studied the clinical and genetic landscape of an unselected cohort of patients with microcephaly. Methods: We performed clinical assessment, high-resolution chromosomal microarray analysis, exome sequencing, and functional studies in 62 patients (58% with primary microcephaly [PM], 27% with secondary microcephaly [SM], and 15% of unknown onset). Results: We found severity of developmental delay/intellectual disability correlating with severity of microcephaly in PM, but not SM. We detected causative variants in 48.4% of patients and found divergent inheritance and variant pattern for PM (mainly recessive and likely gene-disrupting [LGD]) versus SM (all dominant de novo and evenly LGD or missense). While centrosome-related pathways were solely identified in PM, transcriptional regulation was the most frequently affected pathway in both SM and PM. Unexpectedly, we found causative variants in different mitochondria-related genes accounting for 5% of patients, which emphasizes their role even in syndromic PM. Additionally, we delineated novel candidate genes involved in centrosome-related pathway (SPAG5, TEDC1), Wnt signaling (VPS26A, ZNRF3), and RNA trafficking (DDX1). Conclusion: Our findings enable improved evaluation and genetic counseling of PM and SM patients and further elucidate microcephaly pathways.
CRIS-Team Scopus Importer:2019-09-17
Keywords: genetic counseling; MCPH; mitochondria; primary microcephaly; secondary microcephaly

Encapsulation of Rat Bone Marrow Derived Mesenchymal Stem Cells in Alginate Dialdehyde/Gelatin Microbeads with and without Nanoscaled Bioactive Glass for In Vivo Bone Tissue Engineering. - Rottensteiner-Brandl, Ulrike; Detsch, Rainer; Sarker, Bapi; Lingens, Lara; Köhn, Katrin; Kneser, Ulrich; Boßerhoff, Anja Katrin; Horch, Raymund E.; Boccaccini, Aldo R.; Arkudas, Andreas (Materials, 2018)
Alginate dialdehyde (ADA), gelatin, and nano-scaled bioactive glass (nBG) particles are being currently investigated for their potential use as three-dimensional scaffolding materials for bone tissue engineering. ADA and gelatin provide a three-dimensional scaffold with properties supporting cell adhesion and proliferation. Combined with nanocristalline BG, this composition closely mimics the mineral phase of bone. In the present study, rat bone marrow derived mesenchymal stem cells (MSCs), commonly used as an osteogenic cell source, were evaluated after encapsulation into ADA-gelatin hydrogel with and without nBG. High cell survival was found in vitro for up to 28 days with or without addition of nBG assessed by calcein staining, proving the cell-friendly encapsulation process. After subcutaneous implantation into rats, survival was assessed by DAPI/TUNEL fluorescence staining. Hematoxylin-eosin staining and immunohistochemical staining for the macrophage marker ED1 (CD68) and the endothelial cell marker lectin were used to evaluate immune reaction and vascularization. After in vivo implantation, high cell survival was found after 1 week, with a notable decrease after 4 weeks. Immune reaction was very mild, proving the biocompatibility of the material. Angiogenesis in implanted constructs was significantly improved by cell encapsulation, compared to cell-free beads, as the implanted MSCs were able to attract endothelial cells. Constructs with nBG showed higher numbers of vital MSCs and lectin positive endothelial cells, thus showing a higher degree of angiogenesis, although this difference was not significant. These results support the use of ADA/gelatin/nBG as a scaffold and of MSCs as a source of osteogenic cells for bone tissue engineering. Future studies should however improve long term cell survival and focus on differentiation potential of encapsulated cells in vivo.

Endocytosis of GABA(C) receptors depends on subunit composition and is regulated by protein kinase C-? and protein phosphatase 1 - Linck, Lisa; Binder, Jasmin; Haynl, Christian; Enz, Ralf (Journal of Neurochemistry, 2015)
Neuronal excitability depends on the surface concentration of neurotransmitter receptors. Type C gamma-aminobutyric acid receptors (GABA(C)R) are composed of ? subunits that are highly expressed in the retina. Molecular mechanisms that guide the surface concentration of this receptor type are largely unknown. Previously, we reported physical interactions of GABA(C)R ? subunits with protein kinase C-? (PKC?) via adapter proteins of the ZIP protein family, as well as of protein phosphatase 1 (PP1) via PNUTS. Here, we demonstrate that co-expressing ?1 with ZIP3 and PKC? enhanced basal internalization of GABA(C)R, while receptor internalization was reduced in the presence of PNUTS and PP1. Co-expression of ?1 with individual binding partners showed no alterations, except for PP1. Heterooligomeric GABA(C)R composed of ?1 and ?2 subunits had a significant higher endocytosis rate than ?1 containing homooligomeric receptors. Mutant constructs lacking binding sites for protein interactions ensured the specificity of our data. Finally, substitution of serine and threonine residues with alanines indicated that GABA(C)R internalization depends on serine/threonine kinases and phosphatases, but not on tyrosine phosphorylation. We conclude that GABA(C)R internalization is reciprocally regulated by PKC? and PP1 that are anchored to the receptor via ZIP3 or PNUTS respectively.
EVALuna2:4723

Endogenous Expression of the Human CD83 Attenuates EAE Symptoms in Humanized Transgenic Mice and Increases the Activity of Regulatory T Cells - Zinser, Elisabeth; Naumann, Ronald; Wild, Andreas; Michalski, Julia; Deinzer, Anja; Stich, Lena; Kuhnt, Christine; Steinkasserer, Alexander; Knippertz, Ilka (Frontiers in Immunology, 2019)
The CD83 is a type I membrane protein and part of the immunoglobulin superfamily of receptors. CD83 is involved in the regulation of antigen presentation and dendritic cell dependent allogeneic T cell proliferation. A soluble form of CD83 inhibits dendritic cell maturation and function. Furthermore, CD83 is expressed on activated B cells, T cells, and in particular on regulatory T cells. Previous studies on murine CD83 demonstrated this molecule to be involved in several immune-regulatory processes, comprising that CD83 plays a key role in the development and function of different immune cells. In order to get further insights into the function of the human CD83 and to provide preclinical tools to guide the function of CD83/sCD83 for therapeutic purposes we generated Bacterial Artificial Chromosomes (BAC) transgenic mice. BACs are excellent tools for manipulating large DNA fragments and are utilized to engineer transgenic mice by pronuclear injection. Two different founders of BAC transgenic mice expressing human CD83 (BAC-hCD83(tg) mice) were generated and were examined for the hCD83 expression on different immune cells as well as both the in vitro and in vivo role of human CD83 (hCD83) in health and disease. Here, we found the hCD83 molecule to be present on activated DCs, B cells and subtypes of CD4(+) T cells. CD8(+) T cells, on the other hand, showed almost no hCD83 expression. To address the function of hCD83, we performed in vitro mixed lymphocyte reactions (MLR) as well as suppression assays and we used the in vivo model of experimental autoimmune encephalomyelitis (EAE) comparing wild-type and hCD83-BAC mice. Results herein showed a clearly diminished capacity of hCD83-BAC-derived T cells to proliferate accompanied by an enhanced activation and suppressive activity of hCD83-BAC-derived Tregs. Furthermore, hCD83-BAC mice were found to recover faster from EAE-associated symptoms than wild-type mice, encouraging the relevance also of the hCD83 as a key molecule for the regulatory phenotype of Tregs in vitro and in vivo.
CRIS-Team WoS Importer:2019-07-12

Endogenous Sox8 is a critical factor for timely remyelination and oligodendroglial cell repletion in the cuprizone model - Freudenstein, David; Lippert, Magdalena; Popp, Janina Sophie; Aprato, Jessica; Wegner, Michael; Sock, Elisabeth; Haase, Stefanie; Linker, Ralf A.; González Alvarado, María Nazareth (Scientific Reports, 2023)
Genome-wide association studies identified a single nucleotide polymorphism (SNP) downstream of the transcription factor Sox8, associated with an increased risk of multiple sclerosis (MS). Sox8 is known to influence oligodendrocyte terminal differentiation and is involved in myelin maintenance by mature oligodendrocytes. The possible link of a Sox8 related SNP and MS risk, along with the role of Sox8 in oligodendrocyte physiology prompted us to investigate its relevance during de- and remyelination using the cuprizone model. Sox8−/− mice and wildtype littermates received a cuprizone diet for 5 weeks (wk). Sox8−/− mice showed reduced motor performance and weight compared to wildtype controls. Brains were histologically analysed at the maximum of demyelination (wk 5) and on two time points during remyelination (wk 5.5 and wk 6) for oligodendroglial, astroglial, microglial and myelin markers. We identified reduced proliferation of oligodendrocyte precursor cells at wk 5 as well as reduced numbers of mature oligodendrocytes in Sox8−/− mice at wk 6. Moreover, analysis of myelin markers revealed a delay in remyelination in the Sox8−/− group, demonstrating the potential importance of Sox8 in remyelination processes. Our findings present, for the first time, compelling evidence of a significant role of Sox8 in the context of a disease model.
CRIS-Team Scopus Importer:2023-12-22

Enhanced 3D-databases: A fully electrostatic database of AM1-optimized structures - Beck, Bernd; Horn, Anselm; Clark, Timothy; et al. (Journal of Chemical Information and Computer Sciences, 1998)
In a feasibility study, a single conformation 3D version of the Maybridge database (53 471 compounds) has been produced using geometries optimized with AM1 semiempirical MO-theory. The database entries include full electrostatic information within the NAO-PC model and can be used to generate spectroscopic and physical properties using established QSPR models. The data were generated from the original database using custom cleanup software to remove database inconsistencies and, for instance, to isolate the "interesting" ion of ion pairs, 2D to 3D conversion using CORINA and subsequent geometry optimization using VAMP. The complete geometry optimization run was carried out in less than 15 h elapsed time on a Silicon Graphics Origin 2000 with 126 processors. The total failure rate for the structure cleanup, 2D to 3D conversion, and geometry optimization steps was around 1%.

Enhanced Alcohol Preference and Anxiolytic Alcohol Effects in Niemann-Pick Disease Model in Mice - Kalinichenko, Liubov; Mühle, Christiane; Eulenburg, Volker; Praetner, Marc; Reiche, Martin; Gulbins, Erich; Kornhuber, Johannes; Müller, Christian P. (Frontiers in Neurology, 2019)
Major depression and alcohol use disorder are severe psychiatric diseases affecting the world's population with high comorbidity level. However, the pathogenesis of this comorbidity remains unclear, and no selective treatment for this condition is available. A pathogenic pathway and a possible therapeutic target for the treatment of depression-alcoholism comorbidity based on the hyperfunction of acid sphingomyelinase (Asm) were recently suggested. Here we analyzed the effects of alcohol on the depression/anxiety state of homozygous Asm-knockout mice (Asm-/-), which can be considered as a model of an early stage of Niemann-Pick disease, as well as their drinking pattern under normal and stress conditions. It was observed that forced treatment with alcohol (2 g/kg, i.p.) reduces the anxiety level of Asm-/- mice as measured in the elevated plus maze (EPM) test, but enhances the depression level in the forced swim test (FST). The analysis of drinking pattern of these animals in a free-choice alcohol drinking paradigm revealed higher alcohol intake and preference in Asm-/- mice compared to wild type (wt) littermates. However, this difference was overwritten by the stress exposure. Stronger sedating effects of alcohol were observed in Asm-/- mice compared to wt animals in the loss of righting reflex test after single and repeated alcohol injections (3 g/kg, i.p.). Altogether, the present findings might indicate an Asm involvement in the mechanisms of comorbidity between alcoholism and anxiety/depression.
CRIS-Team WoS Importer:2019-07-19

Enriched environment ameliorates adult hippocampal neurogenesis deficits in Tcf4 haploinsufficient mice - Braun, Kristina; Häberle, Benjamin; Wittmann, Marie-Theres; Lie, Dieter Chichung (BMC Neuroscience, 2020)
Background: Transcription factor 4 (TCF4) has been linked to human neurodevelopmental disorders such as intellectual disability, Pitt-Hopkins Syndrome (PTHS), autism, and schizophrenia. Recent work demonstrated that TCF4 participates in the control of a wide range of neurodevelopmental processes in mammalian nervous system development including neural precursor proliferation, timing of differentiation, migration, dendritogenesis and synapse formation. TCF4 is highly expressed in the adult hippocampal dentate gyrus – one of the few brain regions where neural stem / progenitor cells generate new functional neurons throughout life. Results: We here investigated whether TCF4 haploinsufficiency, which in humans causes non-syndromic forms of intellectual disability and PTHS, affects adult hippocampal neurogenesis, a process that is essential for hippocampal plasticity in rodents and potentially in humans. Young adult Tcf4 heterozygote knockout mice showed a major reduction in the level of adult hippocampal neurogenesis, which was at least in part caused by lower stem/progenitor cell numbers and impaired maturation and survival of adult-generated neurons. Interestingly, housing in an enriched environment was sufficient to enhance maturation and survival of new neurons and to substantially augment neurogenesis levels in Tcf4 heterozygote knockout mice. Conclusion: The present findings indicate that haploinsufficiency for the intellectual disability- and PTHS-linked transcription factor TCF4 not only affects embryonic neurodevelopment but impedes neurogenesis in the hippocampus of adult mice. These findings suggest that TCF4 haploinsufficiency may have a negative impact on hippocampal function throughout adulthood by impeding hippocampal neurogenesis.
CRIS-Team Scopus Importer:2020-12-04
Keywords: Adult neurogenesis; Enriched environment; Hippocampus; Intellectual disability; PTHS; Tcf4

Ep400 deficiency in Schwann cells causes persistent expression of early developmental regulators and peripheral neuropathy - Fröb, Franziska; Sock, Elisabeth; Tamm, Ernst. R.; Saur, Anna-Lena; Hillgärtner, Simone; Williams, Trevor J.; Fujii, Toshihiro; Fukunaga, Rikiro; Wegner, Michael (Nature Communications, 2019)
Schwann cells ensure efficient nerve impulse conduction in the peripheral nervous system. Their development is accompanied by defined chromatin changes, including variant histone deposition and redistribution. To study the importance of variant histones for Schwann cell development, we altered their genomic distribution by conditionally deleting Ep400, the central subunit of the Tip60/Ep400 complex. Ep400 absence causes peripheral neuropathy in mice, characterized by terminal differentiation defects in myelinating and non-myelinating Schwann cells and immune cell activation. Variant histone H2A.Z is differently distributed throughout the genome and remains at promoters of Tfap2a, Pax3 and other transcriptional regulator genes with transient function at earlier developmental stages. Tfap2a deletion in Ep400-deficient Schwann cells causes a partial rescue arguing that continued expression of early regulators mediates the phenotypic defects. Our results show that proper genomic distribution of variant histones is essential for Schwann cell differentiation, and assign importance to Ep400-containing chromatin remodelers in the process.
CRIS-Team WoS Importer:2019-06-18

Ephrin-B1 controls the columnar distribution of cortical pyramidal neurons by restricting their tangential migration - Dimidschstein, Jordane; Passante, Lara; Dufour, Audrey; Van Den Ameele, Jelle; Tiberi, Luca; Hrechdakian, Tatyana; Adams, Ralf; Klein, Ruediger; Lie, Dieter Chichung; Jossin, Yves; Vanderhaeghen, Pierre (Neuron, 2013)
Neurons of the cerebral cortex are organized in layers and columns. Unlike laminar patterning, the mechanisms underlying columnar organization remain largely unexplored. Here, we show that ephrin-B1 plays a key role in this process through the control of nonradial steps of migration of pyramidal neurons. In vivo gain of function of ephrin-B1 resulted in a reduction of tangential motility of pyramidal neurons, leading to abnormal neuronal clustering. Conversely, following genetic disruption of ephrin-B1, cortical neurons displayed a wider lateral dispersion, resulting in enlarged ontogenic columns. Dynamic analyses revealed that ephrin-B1 controls the lateral spread of pyramidal neurons by limiting neurite extension and tangential migration during the multipolar phase. Furthermore, we identified P-Rex1, a guanine-exchange factor for Rac3, as a downstream ephrin-B1 effector required to control migration during the multipolar phase. Our results demonstrate that ephrin-B1 inhibits nonradial migration of pyramidal neurons, thereby controlling the pattern of cortical columns.
EVALuna2:26322

Epigenetic regulation in myelinating glia: the role of histone 2b monoubiquitination in Schwann cells - Wüst, Hannah; Wegener, Amelie; Johnson, S.; Fröb, Franziska; Wegner, Michael; Sock, Elisabeth (GLIA, 2019)
CRIS-Team WoS Importer:2020-01-10

EPISODIC PSYCHOSIS, ATAXIA, MOTOR NEUROPATHY CAUSED BY A NOVEL MUTATION IN ADPRHL2 - Durmus, Hacer; Sticht, Heinrich; Ceylaner, Serdar; Hashemolhosseini, Said; Parmn, Yesim (NEUROLOGY, 2020)
CRIS-Team WoS Importer:2020-08-21

Episodic psychosis, ataxia, motor neuropathy with pyramidal signs (PAMP sydrome) caused by a novel mutation in ADPRHL2 (AHR3) - Durmus, Hacer; Mertoğlu, Elif; Sticht, Heinrich; Ceylaner, Serdar; Kulaksızoğlu, Işın Baral; Hashemolhosseini, Said; Uçar, Evren Önay; Parman, Yesim (Neurological Sciences, 2021)
Background: The protein “ADP-Ribosylarginine Hydrolase-Like Protein 2” is encoded by ADPRHL2 and reverses ADP-ribosylation. Recently, mutations in ADPRHL2 were found to be associated with a very rare childhood onset severe neurodegeneration syndrome with episodic, stress-induced seizures, ataxia, and axonal neuropathy. In this study, we evaluate a novel mutation in ADPRHL2 leading to an unknown adult onset syndrome “episodic psychosis, ataxia, motor neuropathy with pyramidal signs (PAMP syndrome).” Design/methods: Four patients with episodic psychosis, ataxia, and motor neuropathy with pyramidal signs were included in this study. Results: An index patient presented ataxia, postural tremor in the hands, and hallucinations at age 20 years, which had started after a viral infection. She improved within 3 months without any treatment. Her neurological exam revealed mild distal weakness, brisk DTRs, bilateral Babinski sign, impaired vibration sensation, position, and ataxia. Pes cavus and hammer toes were also noted. EMG revealed neurogenic changes in distal muscles and normal sensory nerve conduction studies. Cranial MRI was normal. She had three more severe episodes in recent years, and her neurologic findings got progressively worse. Two of her older sisters had much milder phenotypes. The phenotype of the fourth patient from an unrelated family was identical with the index patient. All affected patients had homozygous novel NM_017825.3:c.838G>A (p.Ala280Thr) mutations in a highly conserved region of ADPRHL2. Western blot analyses demonstrated that ADPRHL2 was not expressed in these patients. Conclusions: Here, we describe a novel mutation in ADPRHL2, which further expands the phenotypic and genetic spectrum of the patients harboring these mutations.
CRIS-Team Scopus Importer:2021-02-12
Keywords: ADPRHL2; AHR3; Ataxıa; Epısodıc psychosıs; Motor neuropathy

ERK activation and autophagy impairment are central mediators of irinotecan-induced steatohepatitis - Mahli, Abdo; Saugspier, Michael; Koch, Andreas; Sommer, Judith; Dietrich, Peter; Lee, Seren; Thasler, Reinhard; Schulze-Luehrmann, Jan; Lührmann, Anja; Thasler, Wolfgang Erwin; Müller, Martina; Boßerhoff, Anja Katrin; et al. (Gut, 2017)
Preoperative chemotherapy with irinotecan is associated with the development of steatohepatitis, which increases the risk of perioperative morbidity and mortality for liver surgery. The molecular mechanisms of this chemotherapeutic complication are widely unknown.Mechanisms of irinotecan-induced steatohepatitis were studied in primary human hepatocytes in vitro, in mice treated with irinotecan and in liver specimens from irinotecan-treated compared with control patients.Irinotecan dose-dependently induced lipid accumulation and pro-inflammatory gene expression in hepatocytes. This was accompanied by an impairment of mitochondrial function with reduced expression of carnitine palmitoyltransferase I and an induction of acyl-coenzyme A oxidase-1 (ACOX1), oxidative stress and extracellular signal-regulated kinase (ERK) activation. ERK inhibition prevented irinotecan-induced pro-inflammatory gene expression but had only a slight effect on lipid accumulation. However, irinotecan also induced an impairment of the autophagic flux mediated by alkalisation of lysosomal pH. Re-acidification of lysosomal pH abolished irinotecan-induced autophagy impairment and lipid accumulation. Also in mice, irinotecan treatment induced hepatic ACOX1 expression, ERK phosphorylation and inflammation, as well as impairment of autophagy and significant steatosis. Furthermore, irinotecan-treated patients revealed higher hepatic ERK activity, expression of pro-inflammatory genes and markers indicative for a shift to peroxisomal fatty acid oxidation and an impaired autophagic flux. Pretreatment with the multityrosine kinase inhibitor sorafenib did not affect autophagy impairment and steatosis but significantly reduced ERK phosphorylation and inflammatory response in irinotecan-treated hepatocytes and murine livers.Irinotecan induces hepatic steatosis via autophagy impairment and inflammation via ERK activation. Sorafenib appears as a novel therapeutic option for the prevention and treatment of irinotecan-induced inflammation.
EVALuna2:4748

Erythropoietin production by PDGFR-?(+) cells - Gerl, Katharina; Nolan, Karen A.; Karger, Christian; Fuchs, Michaela; Wenger, Roland H.; Stolt, Claus; Willam, Carsten; Kurtz, Armin; Kurt, Birguel (Pflügers Archiv: European Journal of Physiology, 2016)
PDGFR-?-expressing cells of the kidneys are considered as a relevant site of erythropoietin (EPO) production. The origin of these cells, their contribution to renal EPO production, and if PDGFR-?-positive cells in other organs are also capable to express EPO are less clear. We addressed these questions in mice, in which hypoxia-inducible transcription factors were stabilized in PDGFR-?(+) cells by inducible deletion of the von Hippel-Lindau (Vhl) protein. Vhl deletion led to a 600-fold increase of plasma EPO concentration, 170-fold increase of renal EPO messenger RNA (mRNA) levels, and an increase of hematocrit values up to 70 %. Intrarenal localization of EPO-expressing cells coincided with the zonal heterogeneity and distribution of cells expressing PDGFR-?. Amongst a variety of extrarenal organs only adrenal glands showed significant EPO mRNA expression after Vhl deletion in PDGFR-?(+) cells. EPO mRNA, plasma EPO, and hematocrit fell to subnormal values if HIF-2?, but not HIF-1?, was deleted either alone or in combination with Vhl in PDGFR-?(+) cells. Treatment of mice with a prolyl-hydroxylase inhibitor caused an increase of EPO mRNA abundance and plasma EPO concentrations in wild-type mice and in mice lacking HIF-1? in PDGFR-?(+) cells but exerted no effect in mice lacking HIF-2? in PDGFR-?(+) cells. These findings suggest that PDGFR-?(+) cells are the only relevant site of EPO expression in the kidney and that HIF-2 is the essential transcription factor triggering EPO expression therein. Moreover, our findings suggest that PDGFR-?(+) cells elaborating EPO might arise from the metanephric mesenchyme, rather than from the neural crest.
EVALuna2:3861

Establishment of a p-nitrophenol oxidation-based assay for the analysis of CYP2E1 activity in intact hepatocytes in vitro - Mahli, Abdo; Thasler, Wolfgang Erwin; Hellerbrand, Claus (Toxicology Mechanisms and Methods, 2019)
CYP2E1 is a mammalian cytochrome P450 enzyme, which oxidizes a structurally diverse class of endogenous and exogenous (xenobiotic) compounds. Best studied is the role of CYP2E1 in phase I metabolism of xenobiotics including alcohol. CYP2E1 metabolizes ethanol and is active in generating reactive oxygen species (ROS) and subsequent oxidative stress in the hepatic tissues. Several studies have shown and discussed the importance of CYP2E1 in the hepatotoxic actions of alcohol. However, the vast majority assessed the CYP2E1 activity only in isolated microsomes. Here, we aimed to develop and optimize a fast and easy method to assess alcohol-induced CYP2E1 activity in hepatocytes in vitro applying oxidation of para-nitrophenol to para-nitrocatechol as specific substrate probe. Using hepatoma cells with and without stable CYP2E1 expression and primary human hepatocytes, we established specific methodology to assess CYP2E1 catalytic activity and its induction by ethanol in a small number of cells and in a very short time.
CRIS-Team WoS Importer:2019-04-12

Establishment of myelinating Schwann cells and barrier integrity between central and peripheral nervous systems depend on Sox10. - Fröb, Franziska; Kichko, Tetyana; Reeh, Peter; Wegner, Michael; et al. (Glia, 2012)
The transcription factor Sox10 is expressed throughout Schwann cell development and has already been shown to be essential for specification and for the identity and further development of immature Schwann cells. Here, we show that Sox10 is also required in Schwann cells for establishing the myelinating state. This is concluded from the fact that a peripheral neuropathy develops in mice in which Sox10 is deleted by a Cre recombinase whose expression is under control of Krox20 regulatory elements. This neuropathy is characterized by altered marker gene expression along the peripheral nerve, decreased conductivity, and severe persistent hypomyelination. As the Cre recombinase is additionally active in boundary cap cells, we also analyzed the role of Sox10 during embryogenesis in establishment and maintenance of the boundary between central and peripheral nervous systems. Sox10 deletion did not affect establishment or survival of boundary cap cells but appeared to compromise barrier function as cells expressing oligodendrocyte and astrocyte markers were no longer restricted to the central nervous system, and instead found in peripheral nerves. We infer that in addition to its many roles in Schwann cells, Sox10 is also important for the integrity of the boundary between central and peripheral nervous systems. © 2012 Wiley Periodicals, Inc.
UnivIS-Import:2015-03-09:Pub.2012.med.IB.LPCIPDBI.establ
Keywords: Boundary cap cells; CMT; Glia; HMG; Krox20; Peripheral neuropathy; Sry; Transcriptional control

Ethanol consumption decreases autoantibody titers by blocking IL-21 secretion of Tfh cells during the development of arthritis - Azizov, Vugar; Dietel, K.; Kolenbrander, A.; Seubert, S.; Steffen, F.; Meidenbauer, J.; Steffen, Ulrike; Hofmann, Jörg; Nimmerjahn, Falk; Linker, R.; Wirtz, Stefan; Sarter-Zaiss, Kerstin; et al. (EUROPEAN JOURNAL OF IMMUNOLOGY, 2019)
CRIS-Team WoS Importer:2019-10-08

Ethanol consumption inhibits TFH cell responses and the development of autoimmune arthritis - Azizov, Vugar; Dietel, Katharina; Steffen, Franziska; Dürholz, Kerstin; Meidenbauer, Julia; Lucas, Sébastien; Frech, Michael; Omata, Yasunori; Tajik, Narges; Knipfer, Lisa; Kolenbrander, Anne; Seubert, Silvia; et al. (Nature Communications, 2020)
Alcohol consumption is a consistent protective factor for the development of autoimmune diseases such as rheumatoid arthritis (RA). The underlying mechanism for this tolerance-inducing effect of alcohol, however, is unknown. Here we show that alcohol and its metabolite acetate alter the functional state of T follicular helper (TFH) cells in vitro and in vivo, thereby exerting immune regulatory and tolerance-inducing properties. Alcohol-exposed mice have reduced Bcl6 and PD-1 expression as well as IL-21 production by TFH cells, preventing proper spatial organization of TFH cells to form TFH:B cell conjugates in germinal centers. This effect is associated with impaired autoantibody formation, and mitigates experimental autoimmune arthritis. By contrast, T cell independent immune responses and passive models of arthritis are not affected by alcohol exposure. These data clarify the immune regulatory and tolerance-inducing effect of alcohol consumption.
CRIS-Team Scopus Importer:2020-05-05

Ethanol consumption inhibits the development of autoimmunity by blocking IL-21 secretion in T-FH cells - Azizov, Vugar; Dietel, K.; Kolenbrander, A.; Seubert, S.; Steffen, F.; Meidenbauer, J.; Steffen, Ulrike; Hofmann, J.; Nimmerjahn, Falk; Linker, R.; Wirtz, Stefan; Herrmann, Martin; et al. (EUROPEAN JOURNAL OF IMMUNOLOGY, 2019)
CRIS-Team WoS Importer:2019-11-05

Evidence for genetic overlap between adult onset Still's disease and hereditary periodic fever syndromes - Sighart, Regina; Rech, J.; Hueber, Axel; Blank, N.; Löhr, S.; Reis, André; Sticht, Heinrich; Hüffmeier, Ulrike (Rheumatology International, 2017)
Adult onset Still's disease (AOSD) is a severe, autoimmune disease that can be challenging to treat with conventional therapeutics and biologicals in a considerable number of cases. Therefore, there is a high need to understand its pathogenesis better. As major clinical symptoms overlap between AOSD and hereditary periodic fever syndromes (HPFS), we analysed four known HPFS genes in AOSD.We performed Sanger sequencing and quantitative analysis of all coding regions of MEFV, TNFRSF1A, MVK and NLRP3 in 40 AOSD patients. All rare coding variants (n = 6) were evaluated for several aspects to classify them as benign to pathogenic variants. Statistical analysis was performed to analyse whether variants classified as (likely) pathogenic were associated with AOSD.We identified three rare variants in MEFV, one previously not described. Association to the three likely pathogenic MEFV variants was significant (p c = 2.34E- 03), and two of the three carriers had a severe course of disease. We observed strong evidence for significant association to mutations in TNFRSF1A (p c = 2.40E- 04), as 5% of patients (2/40) carried a (likely) pathogenic variant in this gene. Both of them received a biological for treatment.Our results indicate TNFRSF1A as a relevant gene in AOSD, especially in patients with a more challenging course of disease, while causal variants remain to be identified in the majority of patients.
EVALuna2:9382

Evidence that Doublecortin is dispensable for the development of adult born neurons in mice - Merz, Katharina; Lie, Dieter Chichung (PLoS ONE, 2013)
In mammals, adult neural stem cells give rise to new hippocampal dentate granule neurons and interneurons of the olfactory bulb throughout life. The microtubule associated protein Doublecortin (DCX) is expressed by migrating neuroblasts and immature neurons, and is widely used as a stage-specific marker of adult neurogenesis and as a marker to identify neurogenic activity in the adult brain per se. Mutations in the DCX gene have been causally linked to human lissencephalic syndromes. Moreover, embryonic loss of DCX function interferes with neuronal migration and dendritic patterning in a species- and region-specific manner. A putative function of DCX in adult neurogenesis has not been directly explored. Here we show that overexpression of DCX in newly generated dentate granule neurons of the adult mouse brain has no effect on morphological maturation or migration. We also show that micro (mi) RNA-mediated retroviral knockdown of DCX does not alter morphological maturation of adult born dentate granule cells or migration of new neurons in either adult neurogenic niche. Thus, the present data indicate that DCX is dispensable for the development of new neurons in adult mice.
EVALuna2:26317

Evolutionary conserved networks of human height identify multiple Mendelian causes of short stature - Hauer, Nadine; Popp, Bernt; Taher, Leila; Vogl, Carina; Dhandapany, Perundurai S.; Büttner, Christian; Uebe, Steffen; Sticht, Heinrich; Ferrazzi, Fulvia; Ekici, Arif Bülent; De Luca, Alessandro; Klinger, Patricia; et al. (European journal of human genetics, 2019)
Height is a heritable and highly heterogeneous trait. Short stature affects 3% of the population and in most cases is genetic in origin. After excluding known causes, 67% of affected individuals remain without diagnosis. To identify novel candidate genes for short stature, we performed exome sequencing in 254 unrelated families with short stature of unknown cause and identified variants in 63 candidate genes in 92 (36%) independent families. Based on systematic characterization of variants and functional analysis including expression in chondrocytes, we classified 13 genes as strong candidates. Whereas variants in at least two families were detected for all 13 candidates, two genes had variants in 6 (UBR4) and 8 (LAMA5) families, respectively. To facilitate their characterization, we established a clustered network of 1025 known growth and short stature genes, which yielded 29 significantly enriched clusters, including skeletal system development, appendage development, metabolic processes, and ciliopathy. Eleven of the candidate genes mapped to 21 of these clusters, including CPZ, EDEM3, FBRS, IFT81, KCND1, PLXNA3, RASA3, SLC7A8, UBR4, USP45, and ZFHX3. Fifty additional growth-related candidates we identified await confirmation in other affected families. Our study identifies Mendelian forms of growth retardation as an important component of idiopathic short stature.
CRIS-Team Scopus Importer:2019-05-24

Evolutionary conserved sequence elements with embryonic enhancer activity in the vicinity of the mammalian Sox8 gene. - Sock, Elisabeth; Wegner, Michael; et al. (International Journal of Biochemistry & Cell Biology, 2010)
The transcription factor Sox8 is widely and dynamically expressed during embryonic development similar to its close relatives Sox9 and Sox10. Whereas gene-regulatory sequences have been identified in the vicinity of the Sox9 and Sox10 genes, no such sequences are known for Sox8. Here we used sequence conservation between mammals and birds to identify seven regions near the Sox8 gene as potential enhancers. Of these sequences, three indeed functioned as Sox8-specific enhancers in transgenic embryos. They were all localized in the upstream region of the Sox8 gene and distal to the promoter which by itself failed to drive significant transgene expression during embryogenesis. Tissues in which at least one of the three enhancers was active and that are known to express Sox8, included facial mesenchyme, the first branchial arch, peripheral nervous system and other neural crest derivatives as well as central nervous system, eye and limb. Other prominent sites of embryonic Sox8 expression were, however, not covered by the three enhancers arguing that additional enhancers exist that may be not conserved in their sequence between mammals and birds or located outside the 220 kb genomic interval analyzed in this study. © 2009 Elsevier Ltd. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2010.med.IB.LPCIPDBI.evolut
Keywords: Enhancer; Evolutionary conserved sequence; High-mobility-group; Neural crest; Peripheral nervous system; Sry

Evolution of regulatory signatures in primate cortical neurons at cell-type resolution - Kozlenkov, Alexey; Vermunt, Marit W.; Apontes, Pasha; Li, Junhao; Hao, Ke; Sherwood, Chet C.; Hof, Patrick R.; Ely, John J.; Wegner, Michael; Mukamel, Eran A.; Creyghton, Menno P.; Koonin, Eugene V.; et al. (Proceedings of the National Academy of Sciences of the United States of America, 2020)
The human cerebral cortex contains many cell types that likely underwent independent functional changes during evolution. However, cell-type–specific regulatory landscapes in the cortex remain largely unexplored. Here we report epigenomic and transcriptomic analyses of the two main cortical neuronal subtypes, glutamatergic projection neurons and GABAergic interneurons, in human, chimpanzee, and rhesus macaque. Using genome-wide profiling of the H3K27ac histone modification, we identify neuron-subtype–specific regulatory elements that previously went undetected in bulk brain tissue samples. Human-specific regulatory changes are uncovered in multiple genes, including those associated with language, autism spectrum disorder, and drug addiction. We observe preferential evolutionary divergence in neuron subtype-specific regulatory elements and show that a substantial fraction of pan-neuronal regulatory elements undergoes subtype-specific evolutionary changes. This study sheds light on the interplay between regulatory evolution and cell-type–dependent gene-expression programs, and provides a resource for further exploration of human brain evolution and function.
CRIS-Team Scopus Importer:2020-12-11
Keywords: GABAergic neurons; Glutamatergic neurons; H3K27ac histone modification; Primate evolution; Regulatory elements

Expanding the clinical and molecular spectrum of the novel CYFIP2-related neurodevelopmental disorder and functional proof of aberrant WRC-mediated actin dynamics - Begemann, A.; Sticht, Heinrich; Mcwalter, K.; Vitobello, A.; Faivre, L.; Alhaddad, B.; Banka, S.; Becker, J.; Bierhals, T.; Brown, K.; Bruel, A.; Brunet, T.; et al. (EUROPEAN JOURNAL OF HUMAN GENETICS, 2020)
CRIS-Team WoS Importer:2021-01-22

Expanding the clinical and mutational spectrum of Kaufman oculocerebrofacial syndrome with biallelic UBE3B mutations - Basel-Vanagaite, Lina; Yilmaz, Rustem; Tang, Sha; Reuter, Miriam; Rahner, Nils; Grange, Dorothy K.; Mortenson, Megan; Koty, Patrick; Feenstra, Heather; Gonzalez, Kelly D. Farwell; Sticht, Heinrich; Boddaert, Nathalie; et al. (Human genetics, 2014)
Biallelic mutations of UBE3B have recently been shown to cause Kaufman oculocerebrofacial syndrome (also reported as blepharophimosis-ptosis-intellectual disability syndrome), an autosomal recessive condition characterized by hypotonia, developmental delay, intellectual disability, congenital anomalies, characteristic facial dysmorphic features, and low cholesterol levels. To date, six patients with either missense mutations affecting the UBE3B HECT domain or truncating mutations have been described. Here, we report on the identification of homozygous or compound heterozygous UBE3B mutations in six additional patients from five unrelated families using either targeted UBE3B sequencing in individuals with suggestive facial dysmorphic features, or exome sequencing. Our results expand the clinical and mutational spectrum of the UBE3B-related disorder in several ways. First, we have identified UBE3B mutations in individuals who previously received distinct clinical diagnoses: two sibs with Toriello-Carey syndrome as well as the patient reported to have a "new" syndrome by Buntinx and Majewski in 1990. Second, we describe the adult phenotype and clinical variability of the syndrome. Third, we report on the first instance of homozygous missense alterations outside the HECT domain of UBE3B, observed in a patient with mildly dysmorphic facial features. We conclude that UBE3B mutations cause a clinically recognizable and possibly underdiagnosed syndrome characterized by distinct craniofacial features, hypotonia, failure to thrive, eye abnormalities, other congenital malformations, low cholesterol levels, and severe intellectual disability. We review the UBE3B-associated phenotypes, including forms that can mimick Toriello-Carey syndrome, and suggest the single designation "Kaufman oculocerebrofacial syndrome".
EVALuna2:9227

Expanding the clinical spectrum of COL1A1 mutations in different forms of glaucoma - Mauri, Lucia; Uebe, Steffen; Sticht, Heinrich; Vossmerbaeumer, Urs; Weisschuh, Nicole; Manfredini, Emanuela; Maselli, Edoardo; Patrosso, Mariacristina; Weinreb, Robert N.; Penco, Silvana; Reis, André; Pasutto, Francesca (Orphanet Journal of Rare Diseases, 2016)
Primary congenital glaucoma (PCG) and early onset glaucomas are one of the major causes of children and young adult blindness worldwide. Both autosomal recessive and dominant inheritance have been described with involvement of several genes including CYP1B1, FOXC1, PITX2, MYOC and PAX6. However, mutations in these genes explain only a small fraction of cases suggesting the presence of further candidate genes.To elucidate further genetic causes of these conditions whole exome sequencing (WES) was performed in an Italian patient, diagnosed with PCG and retinal detachment, and his unaffected parents. Sanger sequencing of the complete coding region of COL1A1 was performed in a total of 26 further patients diagnosed with PCG or early onset glaucoma. Exclusion of pathogenic variations in known glaucoma genes as CYP1B1, MYOC, FOXC1, PITX2 and PAX6 was additionally done per Sanger sequencing and Multiple Ligation-dependent Probe Amplification (MLPA) analysis.In the patient diagnosed with PCG and retinal detachment, analysis of WES data identified compound heterozygous variants in COL1A1 (p.Met264Leu; p.Ala1083Thr). Targeted COL1A1 screening of 26 additional patients detected three further heterozygous variants (p.Arg253*, p.Gly767Ser and p.Gly154Val) in three distinct subjects: two of them diagnosed with early onset glaucoma and mild form of osteogenesis imperfecta (OI), one patient with a diagnosis of PCG at age 4 years. All five variants affected evolutionary, highly conserved amino acids indicating important functional restrictions. Molecular modeling predicted that the heterozygous variants are dominant in effect and affect protein stability and thus the amount of available protein, while the compound heterozygous variants act as recessive alleles and impair binding affinity to two main COL1A1 binding proteins: Hsp47 and fibronectin.Dominant inherited mutations in COL1A1 are known causes of connective tissues disorders such as OI. These disorders are also associated with different ocular abnormalities, although recognition of the common pathology for both features is seldom being recognized. Our results expand the role of COL1A1 mutations in different forms of early-onset glaucoma with and without signs of OI. Thus, we suggest including COL1A1 mutation screening in the genetic work-up of glaucoma cases and detailed ophthalmic examinations with fundus analysis in patients with OI.
EVALuna2:9324

Expanding the genotypic and phenotypic spectrum of severe serine biosynthesis disorders - Abdelfattah, Fatima; Kariminejad, Ariana; Kahlert, Anne Karin; Morrison, Patrick J.; Gumus, Evren; Mathews, Katherine D.; Darbro, Benjamin W.; Amor, David J.; Walsh, Maie; Sznajer, Yves; Weiß, Luisa; Weidensee, Sabine; et al. (Human Mutation, 2020)
Serine biosynthesis disorders comprise a spectrum of very rare autosomal recessive inborn errors of metabolism with wide phenotypic variability. Neu–Laxova syndrome represents the most severe expression and is characterized by multiple congenital anomalies and pre- or perinatal lethality. Here, we present the mutation spectrum and a detailed phenotypic analysis in 15 unrelated families with severe types of serine biosynthesis disorders. We identified likely disease-causing variants in the PHGDH and PSAT1 genes, several of which have not been reported previously. Phenotype analysis and a comprehensive review of the literature corroborates the evidence that serine biosynthesis disorders represent a continuum with varying degrees of phenotypic expression and suggest that even gradual differences at the severe end of the spectrum may be correlated with particular genotypes. We postulate that the individual residual enzyme activity of mutant proteins is the major determinant of the phenotypic variability, but further functional studies are needed to explore effects at the enzyme protein level.
CRIS-Team Scopus Importer:2020-07-24
Keywords: autosomal recessive; genotype–phenotype correlation; l-serine biosynthesis; Neu–Laxova syndrome; PHGDH; PSAT1

Experimental lupus is aggravated in mouse strains with impaired induction of neutrophil extracellular traps - Kienhofer, Deborah; Hahn, Jonas; Stoof, Julia; Csepregi, Janka Zsofia; Reinwald, Christiane; Urbonaviciute, Vilma; Johnsson, Caroline; Maueröder, Christian; Podolska, Malgorzata; Biermann, Mona; Leppkes, Moritz; Harrer, Thomas; et al. (JCI Insight, 2017)
Many effector mechanisms of neutrophils have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). Neutrophil extracellular traps (NETs) have been assigned a particularly detrimental role. Here we investigated the functional impact of neutrophils and NETs on a mouse model of lupus triggered by intraperitoneal injection of the cell death-inducing alkane pristane. Pristane-induced lupus (PIL) was aggravated in 2 mouse strains with impaired induction of NET formation, i.e., NOX2-deficient (Ncf1-mutated) and peptidyl arginine deiminase 4-deficient (PAD4-deficient) mice, as seen from elevated levels of antinuclear autoantibodies (ANAs) and exacerbated glomerulonephritis. We observed a dramatically reduced ability to form pristane-induced NETs in vivo in both Ncf1-mutated and PAD4-deficient mice, accompanied by higher levels of inflammatory mediators in the peritoneum. Similarly, neutropenic Mcl-1ΔMyelo mice exhibited higher levels of ANAs, which indicates a regulatory function in lupus of NETs and neutrophils. Blood neutrophils from Ncf1-mutated and human individuals with SLE exhibited exuberant spontaneous NET formation. Treatment with specific chemical NOX2 activators induced NET formation and ameliorated PIL. Our findings suggest that aberrant NET is one of the factors promoting experimental lupus-like autoimmunity by uncontrolled release of inflammatory mediators.
EVALuna2:1833

Exploring the phenotypical spectrum of BRD4 defects - Hauer, Nadine; Vogl, C.; Popp, Bernt; Buettner, C.; Uebe, S.; Sticht, Heinrich; Ekici, Arif Bülent; Klinger, Patricia; Kraus, Cornelia; Krumbiegel, M.; Wiesener, A.; Dörr, Helmuth-Günther; et al. (EUROPEAN JOURNAL OF HUMAN GENETICS, 2019)
CRIS-Team WoS Importer:2019-10-25

Expression and function of microRNA-188-5p in activated rheumatoid arthritis synovial fibroblasts - Ruedel, Anke; Dietrich, Peter; Schubert, Thomas; Hofmeister, Simone; Hellerbrand, Claus; Boßerhoff, Anja Katrin (International Journal of Clinical and Experimental Pathology, 2015)
Activated synovial fibroblasts in rheumatoid arthritis (RASF) play a critical role in the pathology of rheumatoid arthritis (RA). Recent studies suggested that deregulation of microRNAs (miRs) affects the development and progression of RA. Therefore, we aimed to identify de-regulated miRs in RASF and to identify target genes that may contribute to the aggressive phenotype of RASF. Quantitative real-time PCR revealed a marked downregulation of miR-188-5p in synovial tissue samples of RA patients as well as in RASF. Exposure to the cytokine interleukine-1? lead to a further downregulation of miR-188-5p expression levels compared to control cells. Re-expression of miR-188-5p in RASF by transient transfection significantly inhibited cell migration. However, miR-188-5p re-expression had no effects on glycosaminoglycan degradation or expression of repellent factors, which have been previously shown to affect the invasive behavior of RASF. In search for target genes of miR-188-5p in RASF we performed gene expression profiling in RASF and found a strong regulatory effect of miR-188-5p on the hyaluronan binding protein KIAA1199 as well as collagens COL1A1 and COL12A1, which was confirmed by qRT-PCR. In silico analysis revealed that KIAA1199 carries a 3'UTR binding site for miR-188-5p. COL1A1and COL12A1 showed no binding site in the mRNA region, suggesting an indirect regulation of these two genes by miR-188-5p. In summary, our study showed that miR-188-5p is down-regulated in RA in vitro and in vivo, most likely triggered by an inflammatory environment. MiR-188-5p expression is correlated to the activation state of RASF and inhibits migration of these cells. Furthermore, miR-188-5p is directly and indirectly regulating the expression of genes, which may play a role in extracellular matrix formation and destruction in RA. Herewith, this study identified potential novel therapeutic targets to inhibit the development and progression of RA.
EVALuna2:4744

Expression of Bone Morphogenetic Protein 14 in Liver Disease and Cancer - Sommer, Judith; Thasler, Wolfgang E.; Boßerhoff, Anja Katrin; Hellerbrand, Claus (Livers, 2023)
The activation of hepatic stellate cells (HSCs) is the key event of hepatic fibrosis. Furthermore, activated HSCs also play an important role in the progression of hepatocellular cancer (HCC). Bone morphogenetic protein 14 (BMP14) is a member of the TGF-β/BMP superfamily. So far, most studies have analyzed BMP14 in the context of bone and cartilage formation and homeostasis. The aim of this study was to assess the expression and function of BMP14 in liver fibrosis and HCC. The BMP14 expression increased during the in vitro activation of primary human HSCs and also in mouse models of liver fibrosis. In human HCC, as well as non-tumorous liver tissues, there was a significant correlation between the expression of BMP14 and alpha-smooth-muscle actin (α-SMA), an established marker for HSC activation. RNAi-mediated BMP14 suppression in activated HSCs resulted in the reduced expression of the transcription factors inhibitor of differentiation 1 (ID1) and ID2, known targets of BMP signaling. Interestingly, α-SMA and collagen expression was also reduced in BMP14-depleted cells, while treatment with recombinant BMP14 induced ID1, ID2, α-SMA and collagen expression. In human HCC cell lines, treatment with recombinant BMP14 induced proliferation, migratory activity and colony formation. In summary, our data indicate activated HSCs as a major cellular source of enhanced BMP14 expression in fibrotic liver disease and HCC, and show that BMP14 exhibits pro-fibrogenic as well as pro-tumorigenic effects. Future analyses will reveal the potential of this soluble growth factor as a therapeutic target or prognostic marker for the progression of fibrosis and HCC in patients with chronic liver disease.
CRIS-Team Scopus Importer:2023-11-17
Keywords: BMP14; hepatic stellate cells; hepatocellular cancer; liver fibrosis

Expression of Connexin47 in oligodendrocytes is regulated by the Sox10 transcription factor. - Wegner, Michael; Glaser, Gabriele; et al. (Journal of Molecular Biology, 2006)
In the central nervous system, Connexin32 and Connexin47 are confined to oligodendrocytes where they contribute to myelin formation and maintenance, and are essential for establishing a functional glial syncytium that ensures ionic homeostasis. Despite their importance, not much is known about the regulation of connexin gene expression in oligodendrocytes. Here, we identify group E Sox proteins, in particular Sox10, as essential transcriptional regulators of both connexins. Not only was expression of Connexin32 and Connexin47 severely compromised in spinal cords of mouse mutants with reduced amounts of group E Sox proteins. Sox10 also stimulated in transient transfections the Connexin32 promoter as well as Connexin47 promoter 1b which is the main Connexin47 promoter active in the postnatal spinal cord. Detailed characterization of Connexin47 promoter 1b identified a single monomer binding site that mediated Sox10-dependent promoter activation. The region containing this binding site was also occupied by endogenous Sox10 in 33B oligodendroglioma cells. These results add Connexin47 and Connexin32 to the list of Sox10 target genes and argue that Sox10 may influence transcription of many terminal differentiation and myelination genes in oligodendrocytes as an essential regulatory component of the myelination program. © 2006 Elsevier Ltd. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2006.med.IB.LPCIPDBI.expres
Keywords: HMG; Krox-20; oligodendrocyte; Sox; Sry

Expression of Sox10 gene during human development - Wegner, Michael; et al. (Febs Letters, 1998)
SOX10, a new member of the SOX gene family, is a transcription factor defective in the Dom (Dominant megacolon) mouse and in the human Shah-Waardenburg syndrome. To help unravel its physiological role during human development, we studied SOX10 gene expression in embryonic, fetal, and adult human tissues by Northern blot and in situ hybridization. As in mice, the human SOX10 gene was essentially expressed in the neural crest derivatives that contribute to the formation of the peripheral nervous system, and in the adult central nervous system. Nevertheless, it was more widely expressed in humans than in rodents. The spatial and temporal pattern of SOX10 expression supports an important function in neural crest development. Copyright (C) 1998 Federation of European Biochemical Societies.
UnivIS-Import:2015-03-05:Pub.1998.med.IB.LPCIPDBI.expres_83
Keywords: Human; In situ hybridization; Neural crest; Northern blot; SOX10

Expression of Sox4 and Sox11 is regulated by multiple mechanisms during retinal development. - Wegner, Michael; et al. (Febs Letters, 2013)
Sox11 and Sox4 play critical roles in retinal development, during which they display specific and unique expression patterns. The expression of Sox11 and Sox4 is temporally sequential, albeit spatially overlapping in some retinal subtypes. Gain-of-function and loss-of-function analyses suggested that Notch signaling suppresses Sox4 expression in the early developing retina but not during the later period of development. The levels of histone H3-acetylation and H3-lysine 4 tri-methylation at the Sox11 locus declined during development, as did the levels of Sox11. A similar but less marked change was seen for Sox4. For both genes, histone H3-lysine 27 methylation was low during development and increased markedly in the adult. © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2013.med.IB.LPCIPDBI.expres
Keywords: Development; Histone modification; Notch; Retina; Sox C family transcription factor; Transcriptional regulation

Expression of SoxE and SoxD genes in human gliomas. - Wegner, Michael; et al. (Neuropathology and Applied Neurobiology, 2007)
Members of group E and group D of the Sox gene family function as important transcriptional regulators of glial development in the central nervous system. Here, we have examined Sox gene expression in 60 human primary gliomas. Transcripts from each of the six group E and group D genes were expressed in gliomas of various types and malignancy grades, but with significant differences. SOX5, SOX9 and SOX10 were generally expressed at levels similar to or below those in adult brain tissue. In contrast, many oligodendrogliomas exhibited upregulation of SOX6, SOX8 and SOX13. Furthermore, loss of heterozygosity on chromosomal arms 1p and 19q was associated with significantly higher SOX8 mRNA levels. Low-grade astrocytomas, but not glioblastomas, also showed elevated SOX8 transcript levels. Taken together, the expression pattern of Sox genes in gliomas is heterogeneous and overall compatible with the less differentiated state of glioma cells as compared with their normal adult counterparts. Despite their restricted expression in astrocytes and oligodendrocytes during normal development, none of the Sox genes was selectively expressed in tumours of the oligodendroglial or astrocytic lineage. This is compatible with an origin of gliomas from neuroepithelial stem or precursor cells. © 2007 Blackwell Publishing Ltd.
UnivIS-Import:2015-03-09:Pub.2007.med.IB.LPCIPDBI.expres
Keywords: Astrocytoma; Oligodendroglioma; SoxD; SoxE; Sry-box

Expression of Sox transcription factors in the developing mouse pancreas. - Wegner, Michael; et al. (Developmental Dynamics, 2003)
Previous work has identified members of the homeodomain and basic helix-loop-helix families of transcription factors as critical determinants of mammalian pancreatic development. Here, we describe the identification of HMG-box transcription factors of the Sox gene family in the mouse pancreas. We detected transcripts for Sox11, Sox4, Sox13, Sox5, Sox9, Sox8, Sox10, Sox7, Sox17, Sox18, Sox15, and Sox30 in embryonic pancreas and found Sox4, Sox9, and Sox13 in adult pancreatic islets. Expression of seven of these Sox factors was studied in more detail by in situ hybridization from the stage of early pancreatic outgrowth to birth. Expression of Sox11 was found in the mesenchyme surrounding the pancreatic buds, whereas Sox4 and Sox9 were confined to the pancreatic epithelium and later to islets. Sox13 and L-Sox5 showed expression in most of the pancreatic epithelial cells between embryonic days 12.5 and 14.5. Sox8 and Sox10 were detected in a thin layer of cells surrounding the islets. The expression patterns of Sox genes in the embryonic pancreas suggest that they could have important and possibly redundant functions in pancreas development. © 2003 Wiley-Liss, Inc.
UnivIS-Import:2015-04-14:Pub.2003.med.IB.LPCIPDBI.expres
Keywords: Development; Embryo; Glucagon; Insulin; Islet; Mouse; Pancreas; Sox; Transcription factor

Expression of the mRNA of seven metabotropic glutamate receptors (mGluR1 to 7) in the rat retina. An in situ hybridization study on tissue sections and isolated cells. - Enz, Ralf; et al. (European Journal of Neuroscience, 1995)
UnivIS-Import:2017-12-18:Pub.1995.med.IB.profes_1.expres_65
Keywords: glutamate; hybridization; in situ; metabotropic receptors; oligonucleotide probes

Expression of the voltage-gated chloride channel ClC-2 in rod bipolar cells of the rat retina. - Enz, Ralf; et al. (Journal of Neuroscience, 1999)
Voltage-gated chloride channels (ClC) are highly conserved during evolution and appear to participate in a variety of physiological functions. Recently, ClC-2 was proposed to play a role in stabilizing the chloride equilibrium potential near or below the resting membrane potential in neurons expressing ligand-gated chloride channels. Because rod bipolar cells in mammalian retina express three forms of inhibitory ligand-gated chloride channels, we decided to study ClC-2 localization and function in the rat retina. RNA encoding ClC-1, -2, -3, -4, and -5 was detected by reverse transcription-PCR in the rat retina. ClC-2-specific antibodies identified protein on cell bodies and in synaptic layers. Double-immunofluorescence staining revealed that intense ClC-2 immunoreactivity colocalized with PKC- stained rod bipolar cells. Patch-clamp experiments performed with individual rod bipolar cells demonstrated the presence of a time-dependent, inwardly rectified current activated at hyperpolarizing membrane potentials. This current demonstrated selectivity for different anions (Cl- > l- > gluconate), was inhibited by Cd2+, and was minimally reduced by 4,4'- diisothiocyanatostilbene-2,2'-disulphonic acid. These features are consistent with currents generated by ClC-2 channels. Our data indicate that functional ClC-2 channels are present in retinal rod bipolar cells and support a role for ClC-2 in maintaining Cl- homeostasis in neurons with ligand-gated chloride channels.
UnivIS-Import:2017-12-18:Pub.1999.med.IB.profes_1.expres
Keywords: ClC; CNS; GABA receptor; Ligand-gated ion channel; Retina; Rod bipolar cell; Voltage-gated chloride channel

Expression of transcription factors during oligodendroglial development - Wegner, Michael (Microscopy Research and Technique, 2001)
Transcription factors coordinate the orderly changes of gene expression that underlie all developmental processes including those of oligodendrocytes. In comparison to other systems, relatively little is known about the role of transcription factors during oligodendrocyte development. However, recent years have seen the identification of oligodendroglial transcription factors that, not surprisingly, belong to the same gene families that are also important in other tissues or cell lineages. Some transcription factors such as the bHLH (basic helix-loop-helix) proteins Olig-1 and Olig-2 or the high-mobility-group protein Sox10 are expressed already early during development of the oligodendrocyte lineage, whereas expression of other transcription factors such as the homeodomain protein Gtx/Nkx6.2 only start at the time of terminal differentiation. Once turned on, expression of these proteins can either be permanent as in the above-mentioned cases or transient as exemplified by the POU domain proteins Tst-1/Oct6/SCIP, Brn-1 and Brn-2. Analyses of these transcription factors has already led to the identification of important principles such as functional redundancy between co-expressed proteins, unexpected divergence in the transcription factor repertoire of oligodendrocytes and Schwann cells, and equally unsuspected similarities in transcription factor usage between oligodendrocytes and neurons. Although so far only a small percentage of oligodendroglial transcription factors has been identified, these are excellent candidates for regulators of cell type specification, lineage progression, and terminal differentiation. © 2001 Wiley-Liss, Inc.
UnivIS-Import:2015-03-09:Pub.2001.med.IB.LPCIPDBI.expres
Keywords: Gtx; Olig-1; Olig-2; Oligodendrocyte; Pax; Pelizaeus-Merzbacher disease; POU; Schwann cell; SCIP; Sox

Expression, purification, and structural analysis of intracellular C-termini from metabotropic glutamate receptors - Seebahn, Angela; Sticht, Heinrich; Enz, Ralf (Methods in Enzymology, 2013)
Glutamate is the most important excitatory neurotransmitter in the mammalian central nervous system (CNS). Metabotropic glutamate receptors (mGluRs) are G-protein-coupled receptors (GPCRs) that guide several intracellular signal cascades thereby controlling multiple physiological tasks, such as neuronal excitability, learning, and memory. Consequently, these receptors are discussed in the context of several CNS-associated diseases, including addiction for drugs, Alzheimer's disease, Fragile X syndrome, night blindness, or schizophrenia. Although increasing structural information is available for the extracellular and transmembrane domains of GPCRs, data describing the nature of intracellular receptor domains are largely missing. Indeed, in all available crystal structures of neurotransmitter receptors, their intracellular domains were omitted. Most intracellular mGluR C-termini are alternatively spliced and contain multiple binding sites for interacting proteins. Therefore, analyzing their structure can identify molecular mechanisms of receptor regulation. Recently, we analyzed the conformation of the intracellular C-termini of mGluR6, mGluR7a, and mGluR8a. Here, we describe an array of biochemical, biophysical, and computational techniques suited to elucidate the nature of these highly interesting receptor domains.
EVALuna2:4686

Externalized decondensed neutrophil chromatin occludes pancreatic ducts and drives pancreatitis - Leppkes, Moritz; Maueröder, Christian; Hirth, Sebastian; Nowecki, Stefanie; Günther, Claudia; Billmeier, Ulrike; Paulus, Susanne; Biermann, Mona; Munoz, Luis Enrique; Hoffmann, Markus; Wildner, Dane; Croxford, Andrew L.; et al. (Nature Communications, 2016)
Ductal occlusion has been postulated to precipitate focal pancreatic inflammation, while the nature of the primary occluding agents has remained elusive. Neutrophils make use of histone citrullination by peptidyl arginine deiminase-4 (PADI4) in contact to particulate agents to extrude decondensed chromatin as neutrophil extracellular traps (NETs). In high cellular density, NETs form macroscopically visible aggregates. Here we show that such aggregates form inside pancreatic ducts in humans and mice occluding pancreatic ducts and thereby driving pancreatic inflammation. Experimental models indicate that PADI4 is critical for intraductal aggregate formation and that PADI4-deficiency abrogates disease progression. Mechanistically, we identify the pancreatic juice as a strong instigator of neutrophil chromatin extrusion. Characteristic single components of pancreatic juice, such as bicarbonate ions and calcium carbonate crystals, induce aggregated NET formation. Ductal occlusion by aggregated NETs emerges as a pathomechanism with relevance in a plethora of inflammatory conditions involving secretory ducts.
EVALuna2:2052

Extracellular Acidosis leads to the Development of a senescent-like Phenotype and molecular Reprogramming of human Melanoma Cells - Böhme, Ines; Boßerhoff, Anja Katrin (2018)
EVALuna2:203601

Extracellular acidosis leads to the formation of a senescence-like subpopulation in malignant melanoma - Chiheb, Chafia; Böhme-Schäfer, Ines; Boßerhoff, Anja Katrin (JOURNAL DER DEUTSCHEN DERMATOLOGISCHEN GESELLSCHAFT, 2022)
CRIS-Team WoS Importer:2022-09-23

Extracellular acidosis triggers a senescence-like phenotype in human melanoma cells - Böhme, Ines; Boßerhoff, Anja Katrin (Pigment Cell & Melanoma Research, 2019)
Acidosis of the tumor microenvironment is a characteristic of solid tumors such as malignant melanoma. Main causes of the extracellular acidification are metabolic alterations in cancer cells. While numerous studies showed that acidosis promotes tumor invasiveness, metastasis, and neoangiogenesis resulting in malignant progression, contrary data reported that acidosis induces cell apoptosis, inhibits cell proliferation, and mediates cell autophagy. Here, we show that low pH (pH 6.7) induces senescent/quiescent phenotype in melanoma cells after long-time treatment defined by induction of SA-beta-galactosidase, upregulation of p21, G(1)/G(0) cell cycle arrest, and reduction of proliferation. Moreover, we revealed that extracellular acidosis triggers the inhibition of eIF2 alpha and subsequently the activation of ATF4 expression, a key component of the integrated stress response (ISR), indicating an acid-mediated translation reprogramming. Interestingly, we also demonstrated that acidosis represses microphthalmia-associated transcription factor (MITF) and activates the expression of the receptor tyrosine kinase AXL. This MITFlow/AXL(high) phenotype is correlated with drug resistance and therapeutic outcome in melanoma. Our results suggest that acidosis is an important microenvironmental factor triggering phenotypic plasticity and promoting tumor progression.
CRIS-Team WoS Importer:2019-08-20

Extracellular aggregated alpha synuclein primarily triggers lysosomal dysfunction in neural cells prevented by trehalose - Hoffmann, Anna-Carin; Minakaki, Georgia; Menges, Stefanie; Salvi, Rachele; Savitskiy, Sergey; Kazman, Aida; Miranda, Hugo Vicente; Mielenz, Dirk; Klucken, Jochen; Winkler, Jürgen; Xiang, Wei (Scientific Reports, 2019)
Cell-to-cell propagation of aggregated alpha synuclein (aSyn) has been suggested to play an important role in the progression of alpha synucleinopathies. A critical step for the propagation process is the accumulation of extracellular aSyn within recipient cells. Here, we investigated the trafficking of distinct exogenous aSyn forms and addressed the mechanisms influencing their accumulation in recipient cells. The aggregated aSyn species (oligomers and fibrils) exhibited more pronounced accumulation within recipient cells than aSyn monomers. In particular, internalized extracellular aSyn in the aggregated forms was able to seed the aggregation of endogenous aSyn. Following uptake, aSyn was detected along endosome-to-lysosome and autophagosome-to-lysosome routes. Intriguingly, aggregated aSyn resulted in lysosomal activity impairment, accompanied by the accumulation of dilated lysosomes. Moreover, analysis of autophagy-related protein markers suggested decreased autophagosome clearance. In contrast, the endocytic pathway, proteasome activity, and mitochondrial homeostasis were not substantially affected in recipient cells. Our data suggests that extracellularly added aggregated aSyn primarily impairs lysosomal activity, consequently leading to aSyn accumulation within recipient cells. Importantly, the autophagy inducer trehalose prevented lysosomal alterations and attenuated aSyn accumulation within aSyn-exposed cells. Our study underscores the importance of lysosomes for the propagation of aSyn pathology, thereby proposing these organelles as interventional targets.
EVALuna2:36381

Fibroblast Growth Factor 9 is expressed by activated hepatic stellate cells and promotes progression of hepatocellular carcinoma - Seitz, Tatjana; Freese, Kim; Dietrich, Peter; Thasler, Wolfgang Erwin; Boßerhoff, Anja Katrin; Hellerbrand, Claus (Scientific Reports, 2020)
Hepatocellular carcinoma (HCC) is closely associated with liver fibrosis. Hepatic stellate cells (HSC) and cancer-associated myofibroblasts are key players in liver fibrogenesis and hepatocarcinogenesis. Overexpression of fibroblast growth factor (FGF) receptors contributes to HCC development and progression. This study aimed to elucidate the role of FGFs in the HSC-HCC crosstalk. Analysis of the expression of the fifteen paracrine FGF-members revealed that FGF9 was only expressed by HSC but not by HCC cells. Also in human HCC tissues, HSC/stromal myofibroblasts were identified as cellular source of FGF9. High expression levels of FGF9 significantly correlated with poor patient survival. Stimulation with recombinant FGF9 induced ERK- and JNK-activation combined with significantly enhanced proliferation, clonogenicity, and migration of HCC cells. Moreover, FGF9 significantly reduced the sensitivity of HCC cells against sorafenib. Protumorigenic effects of FGF9 on HCC cells were almost completely abrogated by the FGFR1/2/3 inhibitor BGJ398, while the selective FGFR4 inhibitor BLU9931 had no significant effect. In conclusion, these data indicate that stroma-derived FGF9 promotes tumorigenicity and sorafenib resistance of HCC cells and FGF9 overexpression correlates with poor prognosis in HCC patients. Herewith, FGF9 appears as potential prognostic marker and novel therapeutic target in HCC.
CRIS-Team Scopus Importer:2020-03-27

Fine-Tuning of Neuronal Ion Channels-Mapping of Residues Involved in Glucose Sensitivity of Recombinant Human Glycine Receptors - Hussein, Rama Ashraf; Ahmed, Marwa; Sticht, Heinrich; Breitinger, Hans Georg; Breitinger, Ulrike (Acs Chemical Neuroscience, 2020)
The inhibitory glycine receptor (GlyR) mediates synaptic inhibition in the spinal cord, brain stem, and other regions of the mammalian central nervous system. Glucose was shown to potentiate α1 GlyRs by interacting with K143. Here, additional amino acids involved in glucose modulation were identified using a structure-based approach of site-directed mutagenesis followed by whole-cell patch-clamp analysis. We identified two additional lysine residues in the α1 GlyR extracellular domain, K16 and K281, that were involved in glucose modulation. Mutation of either residue to alanine abolished glucose potentiation. Residue K281 is located in the same pocket as K143 and could thus contribute to glucose binding. The double mutant K143A-K281A showed a 6-fold increase of EC50, while EC50 of both single mutants K143A and K281A was only slightly increased (1.7- and 1.3-fold, respectively). K16 is located at an analgesic binding site that is distant from the agonist or glucose sites, and the K16A mutation may generate a receptor species that is not potentiated. GlyR position α1-S267 is close to the postulated glucose binding site and known for interactions with ethanol and anesthetics. In the presence of glucose, GlyR α1 mutants S267A, S267I, and S267R showed potentiation, no effect, and reduction of current responses, respectively. This pattern follows that of ethanol modulation and suggests that the interaction sites of glucose and ethanol are identical or located close to each other. Our results support the presence of a distinct binding site for glucose on the glycine receptor, overlapping with the ivermectin/ethanol binding pocket near the transmembrane region and the TM2-3 loop.
CRIS-Team Scopus Importer:2020-11-06
Keywords: ethanol modulation; glucose modulation; Glycine receptor; ion channel function; ion channel potentiation; lysine residues; modulatory sites; mutagenesis; structure modeling

Formation of the node of Ranvier by Schwann cells is under control of transcription factor Sox10 - Saur, Anna-Lena; Fröb, Franziska; Weider, Matthias; Wegner, Michael (Glia, 2021)
The transcription factor Sox10 is an essential regulator of genes that code for structural components of the myelin sheath and for lipid metabolic enzymes in both types of myelinating glia in the central and peripheral nervous systems. In an attempt to characterize additional Sox10 target genes in Schwann cells, we identified in this study a strong influence of Sox10 on the expression of genes associated with adhesion in the MSC80 Schwann cell line. These included the genes for Gliomedin, Neuronal cell adhesion molecule and Neurofascin that together constitute essential Schwann cell contributions to paranode and node of Ranvier. Using bioinformatics and molecular biology techniques we provide evidence that Sox10 directly activates these genes by binding to conserved regulatory regions. For activation, Sox10 cooperates with Krox20, a transcription factor previously identified as the central regulator of Schwann cell myelination. Both the activating function of Sox10 as well as its cooperation with Krox20 were confirmed in vivo. We conclude that the employment of Sox10 and Krox20 as regulators of structural myelin sheath components and genes associated with the node of Ranvier is one way of ensuring a biologically meaningful coordinated formation of both structures during peripheral myelination.
CRIS-Team Scopus Importer:2021-03-05
Keywords: glia; HMG; Krox; node of Ranvier; Schwann cell; Sox

Four-And-A-Half LIM-Domain Protein 2 (FHL2) Deficiency Aggravates Cholestatic Liver Injury - Sommer, Judith; Dorn, Christoph; Gaebele, Erwin; Bataille, Frauke; Freese, Kim; Seitz, Tatjana; Thasler, Wolfgang E.; Buettner, Reinhard; Weiskirchen, Ralf; Boßerhoff, Anja Katrin; Hellerbrand, Claus (Cells, 2020)
Cholestasis occurs in different clinical circumstances and leads to severe hepatic disorders. The four-and-a-half LIM-domain protein 2 (FHL2) is a scaffolding protein that modulates multiple signal transduction pathways in a tissue- and cell context-specific manner. In this study, we aimed to gain insight into the function of FHL2 in cholestatic liver injury. FHL2 expression was significantly increased in the bile duct ligation (BDL) model in mice. In Fhl2-deficient (Fhl2-ko) mice, BDL caused a more severe portal and parenchymal inflammation, extended portal fibrosis, higher serum transaminase levels, and higher pro-inflammatory and pro-fibrogenic gene expression compared to wild type (wt) mice. FHL2 depletion in HepG2 cells with siRNA resulted in a higher expression of the bile acid transporter Na+-taurocholate cotransporting polypeptide (NTCP) gene. Furthermore, FHL2-depleted HepG2 cells showed higher expression of markers for oxidative stress, lower B-cell lymphoma 2 (Bcl2) expression, and higher Bcl2-associated X protein (BAX) expression after stimulation with deoxycholic acid (DCA). In hepatic stellate cells (HSCs), FHL2 depletion caused an increased expression of TGF-β and several pro-fibrogenic matrix metalloproteinases. In summary, our study shows that deficiency in FHL2 aggravates cholestatic liver injury and suggests FHL2-mediated effects on bile acid metabolisms and HSCs as potential mechanisms for pronounced hepatocellular injury and fibrosis.
EVALuna2:212289

Four-and-a-Half LIM-Domain Protein 2 (FHL2) Induces Neuropeptide Y (NPY) in Macrophages in Visceral Adipose Tissue and Promotes Diet-Induced Obesity - Sommer, Judith; Ehnis, Hanna; Seitz, Tatjana; Schneider, Julia; Wild, Andreas; Moceri, Sandra; Buechler, Christa; Bozec, Aline; Weber, Georg; Merkel, Susanne; Beckervordersandforth, Ruth; Steinkasserer, Alexander; et al. (International Journal of Molecular Sciences, 2023)
Obesity is characterized by the expansion of the adipose tissue, usually accompanied by inflammation, with a prominent role of macrophages infiltrating the visceral adipose tissue (VAT). This chronic inflammation is a major driver of obesity-associated comorbidities. Four-and-a-half LIM-domain protein 2 (FHL2) is a multifunctional adaptor protein that is involved in the regulation of various biological functions and the maintenance of the homeostasis of different tissues. In this study, we aimed to gain new insights into the expression and functional role of FHL2 in VAT in diet-induced obesity. We found enhanced FHL2 expression in the VAT of mice with Western-type diet (WTD)-induced obesity and obese humans and identified macrophages as the cellular source of enhanced FHL2 expression in VAT. In mice with FHL2 deficiency (FHL2KO), WTD feeding resulted in reduced body weight gain paralleled by enhanced energy expenditure and uncoupling protein 1 (UCP1) expression, indicative of activated thermogenesis. In human VAT, FHL2 was inversely correlated with UCP1 expression. Furthermore, macrophage infiltration and the expression of the chemokine MCP-1, a known promotor of macrophage accumulation, was significantly reduced in WTD-fed FHL2KO mice compared with wild-type (wt) littermates. While FHL2 depletion did not affect the differentiation or lipid metabolism of adipocytes in vitro, FHL2 depletion in macrophages resulted in reduced expressions of MCP-1 and the neuropeptide Y (NPY). Furthermore, WTD-fed FHL2KO mice showed reduced NPY expression in VAT compared with wt littermates, and NPY expression was enhanced in VAT resident macrophages of obese individuals. Stimulation with recombinant NPY induced not only UCP1 expression and lipid accumulation but also MCP-1 expression in adipocytes. Collectively, these findings indicate that FHL2 is a positive regulator of NPY and MCP-1 expression in macrophages and herewith closely linked to the mechanism of obesity-associated lipid accumulation and inflammation in VAT. Thus, FHL2 appears as a potential novel target to interfere with the macrophage–adipocyte crosstalk in VAT for treating obesity and related metabolic disorders.
CRIS-Team Scopus Importer:2023-11-03
Keywords: adipocytes; FHL2; macrophages; MCP-1; NPY; obesity; thermogenesis

Four-and-a-half LIM-domain protein affects diet induced (hepatic) steatosis and lipid droplet formation - Sommer, Judith; Hellerbrand, Claus (JOURNAL OF HEPATOLOGY, 2018)
CRIS-Team WoS Importer:2019-03-26

FoxO Function Is Essential for Maintenance of Autophagic Flux and Neuronal Morphogenesis in Adult Neurogenesis - Schäffner, Iris; Minakaki, Georgia; Khan, M. Amir; Balta, Elli-Anna; Schlötzer-Schrehardt, Ursula; Schwarz, Tobias J.; Beckervordersandforth, Ruth; Winner, Beate; Webb, Ashley E.; Depinho, Ronald A.; Paik, Jihye; Wurst, Wolfgang; et al. (Neuron, 2018)
Autophagy is a conserved catabolic pathway with emerging functions in mammalian neurodevelopment and human neurodevelopmental diseases. The mechanisms controlling autophagy in neuronal development are not fully understood. Here, we found that conditional deletion of the Forkhead Box O transcription factors FoxO1, FoxO3, and FoxO4 strongly impaired autophagic flux in developing neurons of the adult mouse hippocampus. Moreover, FoxO deficiency led to altered dendritic morphology, increased spine density, and aberrant spine positioning in adult-generated neurons. Strikingly, pharmacological induction of autophagy was sufficient to correct abnormal dendrite and spine development of FoxO-deficient neurons. Collectively, these findings reveal a novel link between FoxO transcription factors, autophagic flux, and maturation of developing neurons.
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Fra1 Controls Rheumatoid Factor Autoantibody Production by Bone Marrow Plasma Cells and the Development of Autoimmune Bone Loss - Grötsch, Bettina; Lux, Anja; Rombouts, Yoann; Hoffmann, Alana; Andreev, Darja; Nimmerjahn, Falk; Xiang, Wei; Scherer, Hans Ulrich; Schett, Georg; Bozec, Aline (Journal of Bone and Mineral Research, 2019)
Next to proinflammatory cytokines, autoimmunity has been identified as a key trigger for osteoclast activation and bone loss. IgG-rheumatoid factor (IgG-RF) immune complexes, which are present in patients with rheumatoid arthritis, were shown to boost osteoclast differentiation. To date, the regulation of IgG-RF production in the absence of inflammatory triggers is unknown. Herein, we describe Fra1 as a key checkpoint that controls IgG-RF production by plasma cells and regulates autoimmune-mediated bone loss. Fra1 deficiency in B cells (Fra1ΔBcell ) led to increased IgG1-producing bone marrow plasma cells, enhanced IgG-RF production, and increased bone loss associated with elevated osteoclast numbers after immunization. The effect of IgG-RF on osteoclasts in vitro and on osteoclasts associated with bone loss in vivo was dependent on FcγR, especially FcγR3. Furthermore, immunization of WT mice with T-cell-dependent antigens induced a significant and robust decrease in Fra1 expression in bone marrow B cells, which was followed by increased IgG1 production and the induction of osteoclast-mediated bone loss. Overall, these data identify Fra1 as a key mediator of IgG-RF production and autoimmune-mediated bone loss. © 2019 American Society for Bone and Mineral Research.
EVALuna2:69394

From CNS stem cells to neurons and glia: Sox for everyone - Reiprich, Simone; Wegner, Michael (Cell and Tissue Research, 2015)
Neuroepithelial precursor cells of the vertebrate central nervous system either self-renew or differentiate into neurons, oligodendrocytes or astrocytes under the influence of a gene regulatory network that consists in transcription factors, epigenetic modifiers and microRNAs. Sox transcription factors are central to this regulatory network, especially members of the SoxB, SoxC, SoxD, SoxE and SoxF groups. These Sox proteins are widely expressed in neuroepithelial precursor cells and in newly specified, differentiating and mature neurons, oligodendrocytes and astrocytes and influence their identity, survival and development. They exert their effect predominantly at the transcriptional level but also have substantial impact on expression at the epigenetic and posttranscriptional levels with some Sox proteins acting as pioneer factors, recruiting chromatin-modifying and -remodelling complexes or influencing microRNA expression. They interact with a large variety of other transcription factors and influence the expression of regulatory molecules and effector genes in a cell-type-specific and temporally controlled manner. As versatile regulators with context-dependent functions, they are not only indispensable for central nervous system development but might also be instrumental for the development of reprogramming and cell conversion strategies for replacement therapies and for assisted regeneration after injury or degeneration-induced cell loss in the central nervous system.
EVALuna2:4967

From head to toes: the multiple facets of Sox proteins - Wegner, Michael (Nucleic Acids Research, 1999)
Sox proteins belong to the HMG box superfamily of DNA-binding proteins and are found throughout the animal kingdom. They are involved in the regulation of such diverse developmental processes as germ layer formation, organ development and cell type specification. Hence, deletion or mutation of Sox proteins often results in developmental defects and congenital disease in humans. Sox proteins perform their function in a complex interplay with other transcription factors in a manner highly dependent on cell type and promoter context. They exhibit a remarkable crosstalk and functional redundancy among each other.
UnivIS-Import:2015-03-05:Pub.1999.med.IB.LPCIPDBI.fromhe

From stem cells to neurons and glia: a soxist's view of neural development. - Wegner, Michael; Stolt, Claus (Trends in Neurosciences, 2005)
During nervous system development, neural stem cells give rise to many different types of neurons and glia over an extended period. Little is known about the intrinsic factors that regulate stem-cell maintenance, decide whether neurons or glia are generated, or control terminal differentiation. Transcription factors of the Sox family provide important clues about the control of these events. In the central nervous system (CNS), Sox1, Sox2 and Sox3 are required for stem-cell maintenance, and their effects are counteracted by Sox21. Sox9, by contrast, alters the potential of stem cells from neurogenic to gliogenic, whereas Sox10 is essential for terminal oligodendrocyte differentiation. In the peripheral nervous system (PNS) the same Sox proteins have different functions, uncovering important developmental differences between the CNS and PNS. © 2005 Elsevier Ltd. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2005.med.IB.LPCIPDBI.fromst

Functional analysis of Sox10 mutations found in human Waardenburg-Hirschsprung patients - Sock, Elisabeth; Wegner, Michael; et al. (Journal of Biological Chemistry, 1998)
The Sry-related protein Sox10 is selectively expressed in neural crest cells during early stages of development and in glial cells of the peripheral and central nervous systems during late development and in the adult. Mutation of the Sox10 gene leads to neural crest defects in the a Dominant megacolon mouse mutant and to combined Waardenburg-Hirschsprung syndrome in humans. Here, we have studied the four Sox10 mutations found to date in Waardenburg-Hirschsprung patients both in the context of the rat and the human cDNA. Unlike the rat Sox10 protein, which failed to show transcriptional activity on its own, human Sox10 displayed a weak, but reproducible, activity as a transcriptional activator. All mutant Sox10 proteins, including the one that only lacked the 106 last amino acids were deficient in this capacity, indicating that the carboxyl terminus of human Sox10 carries a transactivation domain. Whereas all four mutants failed to transactivate, only two failed to synergistically enhance the activity of other transcription factors. Synergy required both the ability to bind to DNA and a region in the amino-terminal part of Sox10. Those mutants that failed to synergize were unable to bind to DNA. Analysis of the naturally occurring Sox10 mutations not only helps to dissect Sox10 structure, but also allows limited predictions on the severity of the disease.
UnivIS-Import:2015-03-05:Pub.1998.med.IB.LPCIPDBI.functi

Functional analysis of Sox8 and Sox9 during sex determination in the mouse. - Wegner, Michael; et al. (Development, 2004)
Sex determination in mammals directs an initially bipotential gonad to differentiate into either a testis or an ovary. This decision is triggered by the expression of the sex-determining gene Sry, which leads to the activation of male-specific genes including the HMG-box containing gene Sox9. From transgenic studies in mice it is clear that Sox9 is sufficient to induce testis formation. However, there is no direct confirmation for an essential role for Sox9 in testis determination. The studies presented here are the first experimental proof for an essential role for Sox9 in mediating a switch from the ovarian pathway to the testicular pathway. Using conditional gene targeting, we show that homozygous deletion of Sox9 in XY gonads interferes with sex cord development and the activation of the male-specific markers Mis and P450scc, and leads to the expression of the female-specific markers Bmp2 and follistatin. Moreover, using a tissue specific knock-out approach, we show that Sox9 is involved in Sertoli cell differentiation, the activation of Mis and Sox8, and the inactivation of Sry. Finally, double knock-out analyses suggest that Sox8 reinforces Sox9 function in testis differentiation of mice.
UnivIS-Import:2015-03-09:Pub.2004.med.IB.LPCIPDBI.functi
Keywords: Conditional gene targeting; Gonads; Mouse; Sex determination

Functional and Structural Relevance of Conserved Positively Charged Lysine Residues in Organic Anion Transporting Polypeptide 1B3 - Mandery, Kathrin; Sticht, Heinrich; Bujok, Krystyna; Schmidt, Ingrid; Fahrmayr, Christina; Balk, Bettina; Fromm, Martin; Gläser, Hartmut (Molecular Pharmacology, 2011)
The human organic anion transporting polypeptide 1B3 (OATP1B3), located in the basolateral membrane of hepatocytes, mediates the uptake of endogenous substrates such as taurocholate and drugs from blood into hepatocytes. The transport activity of OATP1B3 is influenced by positively charged amino acids, which are facing the central pore. Molecular modeling was performed to select conserved positively charged amino acids, which may influence transport activity and anchoring of OATP1B3 in the plasma membrane. The modeling revealed that Lys361 faces the pore, and Lys399 is oriented to the plasma membrane. Therefore, the mutants L361>A, L361>R, L399>A, and L399>R were generated using site-directed mutagenesis to investigate the impact of the positive charges on transport activity and anchoring in the membrane. Transport kinetic analyses for the substrates sulfobromophthalein and taurocholate showed a loss of function for the L361>A mutant, whereas the transport activity was maintained by the L361>R mutant, indicating that the positive charge at position 361 is important for transport activity of OATP1B3. Comparative modeling with OATP1A2 and OATP2B1 revealed that the pore size around this lysine residue is larger in OATP1A2 and smaller in OATP2B1 compared with OATP1B3, which could be related to the respective substrate spectra. Cell surface expression of L399>A and L399>R was decreased to 16 and 72% compared with wild-type OATP1B3 (p < 0.001), respectively, indicating that the positive charge of lysine at position 399 is necessary for an unimpaired cell surface expression. Furthermore, we provide a summary of amino acids, which influence the transport activity of OATP1B3.
EVALuna2:8639

Functional characterization of DNA methylation in the oligodendrocyte lineage. - Wegner, Michael; et al. (Cell Reports, 2016)
Oligodendrocytes derive from progenitors (OPCs) through the interplay of epigenomic and transcriptional events. By integrating high-resolution methylomics, RNA-sequencing, and multiple transgenic lines, this study defines the role of DNMT1 in developmental myelination. We detected hypermethylation of genes related to cell cycle and neurogenesis during differentiation of OPCs, yet genetic ablation of Dnmt1 resulted in inefficient OPC expansion and severe hypomyelination associated with ataxia and tremors in mice. This phenotype was not caused by lineage switch or massive apoptosis but was characterized by a profound defect of differentiation associated with changes in exon-skipping and intron-retention splicing events and by the activation of an endoplasmic reticulum stress response. Therefore, loss of Dnmt1 in OPCs is not sufficient to induce a lineage switch but acts as an important determinant of the coordination between RNA splicing and protein synthesis necessary for myelin formation. Moyon et al. combine high-resolution methylomics, RNA sequencing, and analysis of multiple transgenic lines to define a critical role for DNA methylation in developmental myelination. Ablation of Dnmt1 decreases proliferation yet minimally impacts progenitors while impairing the late stages of differentiation, which require alternative splicing.<br
UnivIS-Import:2018-09-05:Pub.2016.med.IB.LPCIPDBI.functi

Functional consequence of fibulin-4 missense mutations associated with vascular and skeletal abnormalities and cutis laxa - Sasaki, Takako; Hanisch, Franz-Georg; Deutzmann, Rainer; Sakai, Lynn Y.; Sakuma, Tetsushi; Miyamoto, Tatsuo; Yamamoto, Takashi; Hannappel, Ewald; Chu, Mon-Li; Lanig, Harald; Mark, Klaus (Matrix Biology, 2016)
Fibulin-4 is a 60kDa calcium binding glycoprotein that has an important role in development and integrity of extracellular matrices. It interacts with elastin, fibrillin-1 and collagen IV as well as with lysyl oxidases and is involved in elastogenesis and cross-link formation. To date, several mutations in the fibulin-4 gene (FBLN4/EFEMP2) are known in patients whose major symptoms are vascular deformities, aneurysm, cutis laxa, joint laxity, or arachnodactyly. The pathogenetic mechanisms how these mutations translate into the clinical phenotype are, however, poorly understood. In order to elucidate these mechanisms, we expressed fibulin-4 mutants recombinantly in HEK293 cells, purified the proteins in native forms and analyzed alterations in protein synthesis, secretion, matrix assembly, and interaction with other proteins in relation to wild type fibulin-4. Our studies show that different mutations affect these properties in multiple ways, resulting in fibulin-4 deficiency and/or impaired ability to form elastic fibers. The substitutions E126K and C267Y impaired secretion of the protein, but not mRNA synthesis. Furthermore, the E126K mutant showed less resistance to proteases, reduced binding to collagen IV and fibrillin-1, as well as to LTBP1s and LTBP4s. The A397T mutation introduced an extra O-glycosylation site and deleted binding to LTBP1s. We show that fibulin-4 binds stronger than fibulin-3 and -5 to LTBP1s, 3, and 4s, and to the lysyl oxidases LOX and LOXL1; the binding of fibulin-4 to the LOX propeptide was strongly reduced by the mutation E57K. These findings show that different mutations in the fibulin-4 gene result in different molecular defects affecting secretion rates, protein stability, LOX-induced cross-linking, or binding to other ECM components and molecules of the TGF-? pathway, and thus illustrate the complex role of fibulin-4 in connective tissue assembly.
EVALuna2:10217

Functional implications of novel human acid sphingomyelinase splice variants - Rhein, Cosima; Tripal, Philipp; Seebahn, Angela; Konrad, Alice; Kramer, Marcel; Nagel, Christine; Kemper, Jonas; Bode, Jens; Mühle, Christiane; Gulbins, Erich; Reichel, Martin; Becker, Cord-Michael; et al. (PLoS ONE, 2012)
Acid sphingomyelinase (ASM) hydrolyses sphingomyelin and generates the lipid messenger ceramide, which mediates a variety of stress-related cellular processes. The pathological effects of dysregulated ASM activity are evident in several human diseases and indicate an important functional role for ASM regulation. We investigated alternative splicing as a possible mechanism for regulating cellular ASM activity.We identified three novel ASM splice variants in human cells, termed ASM-5, -6 and -7, which lack portions of the catalytic- and/or carboxy-terminal domains in comparison to full-length ASM-1. Differential expression patterns in primary blood cells indicated that ASM splicing might be subject to regulatory processes. The newly identified ASM splice variants were catalytically inactive in biochemical in vitro assays, but they decreased the relative cellular ceramide content in overexpression studies and exerted a dominant-negative effect on ASM activity in physiological cell models.These findings indicate that alternative splicing of ASM is of functional significance for the cellular stress response, possibly representing a mechanism for maintaining constant levels of cellular ASM enzyme activity.
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Functional modulation of regulatory T cells (Tregs) and analyses of the underlying mechanisms - Marosán, Anita; Steinkasserer, Alexander; Wild, Andreas (EUROPEAN JOURNAL OF IMMUNOLOGY, 2022)
CRIS-Team WoS Importer:2023-02-17

Functional null mutations in the gonosomal homologue gene TBL1Y are associated with non-syndromic coarctation of the aorta - Tagariello, Andreas; Breuer, C.; Birkner, Y.; Schmidt, Stefan; Koch, Anna Maria; Cesnjevar, Robert; Rueffer, A.; Dittrich, Sven; Schneider, H.; Winterpacht, Andreas; Sticht, Heinrich; Doetsch, J.; et al. (Current Molecular Medicine, 2012)
In patients with congenital heart defects, chromosomal anomalies are 100 times more frequent than in control subjects. Coarctation of the aorta can be detected in 15-20% of patients with Ullrich-Turner syndrome. By extensively reviewing literature involving breakpoint analysis of gonosomal deletions in Ullrich- Turner syndrome patients with and without coarctation of the aorta, we identified several gonosomal homolgous gene pairs of interest. Four of these homologous gene pairs were investigated by standard DNA sequencing in a cohort of 83 patients with non-syndromic coarctation of the aorta. Subsequently stability of mutant RNA and protein was analyzed to verify functional relevance of detected mutations. We identified two unreported missense mutations in Exon 8 (p.D69H) and 9 (p.R176W) of TBL1Y. Bioinformatic analysis and 3D modelling predicted that both mutations lead to TBL1Y loss of function. In RT-PCR and Western blot analyses of HEK293 cells transfected with a vector carrying the full-length TBL1Y (wild-type and mutant), we documented the predicted protein instability by showing protein decay for both mutant proteins. TBL1Y is similar to its gonosomal homologue, TBL1X, and its autosomal homologue, TBLR1, on chromosome 3. Both genes are part of co-repressor machineries and required for transcriptional activation by transcription factors that involve CtBP1/2, which contributes to Notch signaling. Several studies have shown that Notch signalling is important for proper development of the left ventricular outflow tract. Our findings suggest that TBL1Y is involved in the genesis of non-syndromic coarctation of the aorta.
EVALuna2:9136

Functional Relevance of the Interaction between Human Cyclins and the Cytomegalovirus-Encoded CDK-Like Protein Kinase pUL97 - Schütz, Martin; Steingruber, Mirjam; Socher, Eileen; Müller, Regina; Wagner, Sabrina; Kögel, Merle; Sticht, Heinrich; Marschall, Manfred (Viruses, 2021)
The replication of human cytomegalovirus (HCMV) is characterized by a complex network of virus–host interaction. This involves the regulatory viral protein kinase pUL97, which represents a viral cyclin-dependent kinase ortholog (vCDK) combining typical structural and functional features of host CDKs. Notably, pUL97 interacts with the three human cyclin types T1, H and B1, whereby the binding region of cyclin T1 and the region conferring oligomerization of pUL97 were both assigned to amino acids 231–280. Here, we addressed the question of whether recombinant HCMVs harboring deletions in this region were impaired in cyclin interaction, kinase functionality or viral replication. To this end, recombinant HCMVs were generated by traceless BACmid mutagenesis and were phenotypically characterized using a methodological platform based on qPCR, coimmunoprecipitation, in vitro kinase assay (IVKA), Phos-tag Western blot and confocal imaging analysis. Combined data illustrate the following: (i) infection kinetics of all three recombinant HCMVs, i.e., ORF-UL97 ∆231–255, ∆256–280 and ∆231–280, showed impaired replication efficiency compared to the wild type, amongst which the largest deletion exhibited the most pronounced defect; (ii) specifically, this mutant ∆231–280 showed a loss of interaction with cyclin T1, as demonstrated by CoIP and confocal imaging; (iii) IVKA and Phos-tag analyses revealed strongly affected kinase activity for ∆231–280, with strong impairment of both autophosphorylation and substrate phosphorylation, but less pronounced impairments for ∆231–255 and ∆256–280; and (iv) a bioinformatic assessment of the pUL97–cyclin T1 complex led to the refinement of our current binding model. Thus, the results provide initial evidence for the functional importance of the pUL97–cyclin interaction concerning kinase activity and viral replication fitness.<br
Keywords: human cytomegalovirus; virus-encoded kinase pUL97; viral CDK ortholog; interaction with human cyclin T1; replication-impaired viral mutants; defects in pUL97 activities; pUL97–cyclin functional importance

Further characterization of Borjeson-Forssman-Lehmann syndrome in females due to de novo variants in PHF6 - Gerber, Celine B.; Fliedner, Anna; Bartsch, Oliver; Berland, Siren; Dewenter, Malin; Haug, Marte; Hayes, Ian; Marin-Reina, Purificacion; Mark, Paul R.; Martinez-Castellano, Francisco; Maystadt, Isabelle; Karadurmus, Deniz; et al. (Clinical Genetics, 2022)
While inherited hemizygous variants in PHF6 cause X-linked recessive Borjeson-Forssman-Lehmann syndrome (BFLS) in males, de novo heterozygous variants in females are associated with an overlapping but distinct phenotype, including moderate to severe intellectual disability, characteristic facial dysmorphism, dental, finger and toe anomalies, and linear skin pigmentation. By personal communication with colleagues, we assembled 11 additional females with BFLS due to variants in PHF6. We confirm the distinct phenotype to include variable intellectual disability, recognizable facial dysmorphism and other anomalies. We observed skewed X-inactivation in blood and streaky skin pigmentation compatible with functional mosaicism. Variants occurred de novo in 10 individuals, of whom one was only mildly affected and transmitted it to her more severely affected daughter. The mutational spectrum comprises a two-exon deletion, five truncating, one splice-site and three missense variants, the latter all located in the PHD2 domain and predicted to severely destabilize the domain structure. This observation supports the hypothesis of more severe variants in females contributing to gender-specific phenotypes in addition to or in combination with effects of X-inactivation and functional mosaicism. Therefore, our findings further delineate the clinical and mutational spectrum of female BFLS and provide further insights into possible genotype-phenotype correlations between females and males.
CRIS-Team WoS Importer:2022-06-24
Keywords: Borjeson-Forssman-Lehmann syndrome; de novo; PHF6; X-chromosomal

Further clinical and molecular delineation of spondylocostal dysostosis type 3 - Schuhmann, Sarah; Koller, H.; Sticht, Heinrich; Kraus, Cornelia; Krumbiegel, Mandy; Uebe, Steffen; Ekici, Arif Bülent; Reis, André; Thiel, C. T. (EUROPEAN JOURNAL OF HUMAN GENETICS, 2020)
CRIS-Team WoS Importer:2021-01-22

Further corroboration of distinct functional features in SCN2A variants causing intellectual disability or epileptic phenotypes - Begemann, Anais; Acuna, Mario A.; Zweier, Markus; Vincent, Marie; Steindl, Katharina; Bachmann-Gagescu, Ruxandra; Hackenberg, Annette; Abela, Lucia; Plecko, Barbara; Kroell-Seger, Judith; Baumer, Alessandra; Yamakawa, Kazuhiro; et al. (Molecular Medicine, 2019)
Background: Deleterious variants in the voltage-gated sodium channel type 2 (Na(v)1.2) lead to a broad spectrum of phenotypes ranging from benign familial neonatal-infantile epilepsy (BFNIE), severe developmental and epileptic encephalopathy (DEE) and intellectual disability (ID) to autism spectrum disorders (ASD). Yet, the underlying mechanisms are still incompletely understood.
CRIS-Team WoS Importer:2019-04-16

GABAC Receptors: A Molecular View. - Enz, Ralf (Biological Chemistry, 2001)
In the central nervous system inhibitory neurotransmission is primarily achieved through activation of receptors for γ-aminobutyric acid (GABA). Three types of GABA receptors have been identified on the basis of their pharmacological and electrophysiological properties. The predominant type, termed GABAA, and a recently identified GABAC type, form ligand-gated chloride channels, whereas GABAB receptors activate separate cation channels via G proteins. Based on their homology to nicotinic acetylcholine receptors, GABAC receptors are believed to be oligomeric protein complexes composed of five subunits in a pentameric arrangement. To date up to five different GABAC receptors subunits have been identified in various species. Recent studies have shed new light on the biological characteristics of GABAC receptors, including the chromosomal localization of its subunit genes and resulting links to deseases, the cloning of new splice variants, the identification of GABAC receptor-associated proteins, the identification of domains involved in subunit assembly, and finally structure/function studies examining functional consequences of introduced mutations. This review summarizes recent data in view of the molecular structure of GABAC receptors and presents new insights into the biological function of this protein in the retina.
UnivIS-Import:2017-12-18:Pub.2001.med.IB.profes_1.gabacr
Keywords: Inhibition; Ligand-gated ion channel; Retina; Rho subunit; Splice variant; Subunit assembly

GABA receptor rho subunit expression in the developing rat brain. - Enz, Ralf; et al. (DEV BRAIN RES, 2005)
Ionotropic GABA C receptors are composed of ρ 1, ρ 2 and ρ 3 subunits. Although the distribution of ρ subunit mRNAs in the adult brain has been studied, information on the developmental regulation of different ρ subunits in the brain is scattered and incomplete. Here, GABA C receptor ρ subunit expression was studied in the developing rat brain. In situ hybridization on postnatal brain slices showed ρ 2 mRNA expression from newborn in superficial gray layer (SGL) of superior colliculus (SuC), and from the first postnatal week in the hippocampal CA1 region and pretectal nucleus of the optic tract. ρ 2 mRNA was also expressed in the adult dorsal lateral geniculate nucleus. Quantitative RT-PCR revealed expression of all three ρ subunits in the hippocampus and superior colliculus from the first postnatal day. In the hippocampus, ρ 2 mRNA expression clearly dominated over ρ 1 and ρ 3, whereas in the superior colliculus, ρ 1 mRNA expression levels were similar to ρ 2. In both areas, a clear up-modulation of ρ 2 and ρ 3 mRNA during the first postnatal week was detected. GABA C receptor protein expression was confirmed in adult hippocampus, superior colliculus and dorsal lateral geniculate nucleus by immunohistochemistry. Our results demonstrate for the first time the expression of all three ρ subunit mRNAs in several regions of the developing and adult rat brain. Our quantitative data allows assessment of putative subunit combinations in the superior colliculus and hippocampus. From the selective distribution of ρ subunits, it may be hypothesized that GABA C receptors are specifically involved in aspects of visual image motion processing in the rat brain. © 2004 Elsevier B.V. All rights reserved.
UnivIS-Import:2017-12-18:Pub.2005.med.IB.profes_1.gabare
Keywords: GABA; Hippocampus; Immunohistochemistry; In situ hybridization; qRT-PCR; Superior colliculus

Gain of Olig2 function in oligodendrocyte progenitors promotes remyelination - Wegener, Amelie; Deboux, Cyrille; Bachelin, Corinne; Frah, Magali; Kerninon, Christophe; Seilhean, Danielle; Weider, Matthias; Wegner, Michael; Nait-Oumesmar, Brahim (Brain, 2015)
The basic helix-loop-helix transcription factor Olig2 is a key determinant for the specification of neural precursor cells into oligodendrocyte progenitor cells. However, the functional role of Olig2 in oligodendrocyte migration and differentiation remains elusive both during developmental myelination and under demyelinating conditions of the adult central nervous system. To decipher Olig2 functions, we generated transgenic mice (TetOlig2:Sox10(rtTA/+)) overexpressing Olig2 in Sox10(+) oligodendroglial cells in a doxycycline inducible manner. We show that Olig2 overexpression increases the generation of differentiated oligodendrocytes, leading to precocious myelination of the central nervous system. Unexpectedly, we found that gain of Olig2 function in oligodendrocyte progenitor cells enhances their migration rate. To determine whether Olig2 overexpression in adult oligodendrocyte progenitor cells promotes oligodendrocyte regeneration for myelin repair, we induced lysophosphatidylcholine demyelination in the corpus callosum of TetOlig2:Sox10(rtTA/+) and control mice. We found that Olig2 overexpression enhanced oligodendrocyte progenitor cell differentiation and remyelination. To assess the relevance of these findings in demyelinating diseases, we also examined OLIG2 expression in multiple sclerosis lesions. We demonstrate that OLIG2 displays a differential expression pattern in multiple sclerosis lesions that correlates with lesion activity. Strikingly, OLIG2 was predominantly detected in NOGO-A(+) (now known as RTN4-A) maturing oligodendrocytes, which prevailed in active lesion borders, rather than chronic silent and shadow plaques. Taken together, our data provide proof of principle indicating that OLIG2 overexpression in oligodendrocyte progenitor cells might be a possible therapeutic mechanism for enhancing myelin repair.
EVALuna2:4980

GCMB mutation in familial isolated hypo-parathyroidism with residual secretion of parathyroid hormone. - Wegner, Michael; Hashemolhosseini, Said; et al. (Journal of Clinical Endocrinology and Metabolism, 2005)
UnivIS-Import:2015-03-09:Pub.2005.med.IB.LPCIPDBI.gcmbmu

Gene dosage-dependent rescue of HSP neurite defects in SPG4 patients' neurons - Havlicek, Steven; Kohl, Zacharias; Mishra, Himanshu Kumar; Prots, Iryna; Eberhardt, Esther; Denguir, Naime; Wend, Holger; Ploetz, Sonja; Boyer, Leah; Marchetto, Maria C. N.; Aigner, Stefan; Sticht, Heinrich; et al. (Human Molecular Genetics, 2014)
The hereditary spastic paraplegias (HSPs) are a heterogeneous group of motorneuron diseases characterized by progressive spasticity and paresis of the lower limbs. Mutations in Spastic Gait 4 (SPG4), encoding spastin, are the most frequent cause of HSP. To understand how mutations in SPG4 affect human neurons, we generated human induced pluripotent stem cells (hiPSCs) from fibroblasts of two patients carrying a c.1684C>T nonsense mutation and from two controls. These SPG4 and control hiPSCs were able to differentiate into neurons and glia at comparable efficiency. All known spastin isoforms were reduced in SPG4 neuronal cells. The complexity of SPG4 neurites was decreased, which was paralleled by an imbalance of axonal transport with less retrograde movement. Prominent neurite swellings with disrupted microtubules were present in SPG4 neurons at an ultrastructural level. While some of these swellings contain acetylated and detyrosinated tubulin, these tubulin modifications were unchanged in total cell lysates of SPG4 neurons. Upregulation of another microtubule-severing protein, p60 katanin, may partially compensate for microtubuli dynamics in SPG4 neurons. Overexpression of the M1 or M87 spastin isoforms restored neurite length, branching, numbers of primary neurites and reduced swellings in SPG4 neuronal cells. We conclude that neurite complexity and maintenance in HSP patient-derived neurons are critically sensitive to spastin gene dosage. Our data show that elevation of single spastin isoform levels is sufficient to restore neurite complexity and reduce neurite swellings in patient cells. Furthermore, our human model offers an ideal platform for pharmacological screenings with the goal to restore physiological spastin levels in SPG4 patients.
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Generation and characterization of an endogenously tagged SPG11-human iPSC line by CRISPR/Cas9 mediated knock-in - Winner, Beate; Krumm, Laura; Pozner, Tatyana; Kaindl, Johanna; Regensburger, Martin; Günther, Claudia; Turan, Sören; Asadollahi, Reza; Rauch, Anita (Stem Cell Research, 2021)
Pathogenic bi-allelic variants in the SPG11 gene result in rare motor neuron disorders such as Hereditary Spastic Paraplegia type 11, Charcot-Marie Tooth, and Juvenile Amyotrophic Lateral Sclerosis-5. The main challenge in SPG11-linked disease research is the lack of antibodies against SPG11 encoded spatacsin. Here, we describe the CRISPR/Cas9 mediated generation and validation of an endogenously tagged SPG11- human iPSC line that contains an HA tag at the C-terminus of SPG11. The line exhibits multi-lineage differentiation potential and holds promise for studying the role of spatacsin and for the elucidation of SPG11-associated pathogenesis. Resource Table.

Gene targeting reveals a widespread role for the high-mobility-group transcription factor Sox11 in tissue remodeling. - Sock, Elisabeth; Wegner, Michael; et al. (Molecular and Cellular Biology, 2004)
The high-mobility-group domain-containing transcription factor Sox11 is expressed transiently during embryonic development in many tissues that undergo inductive remodeling. Here we have analyzed the function of Sox11 by gene deletion in the mouse. Sox11-deficient mice died at birth from congenital cyanosis, likely resulting from heart defects. These included ventricular septation defects and outflow tract malformations that ranged from arterial common trunk to a condition known as double outlet right ventricle. Many other organs that normally express Sox11 also exhibited severe developmental defects. We observed various craniofacial and skeletal malformations, asplenia, and hypopiasia of the lung, stomach, and pancreas. Eyelids and the abdominal wall did not close properly in some Sox11-deficient mice. This phenotype suggests a prime function for Sox11 in tissue remodeling and identifies SOX11 as a potentially mutated gene in corresponding human malformation syndromes.
UnivIS-Import:2015-03-09:Pub.2004.med.IB.LPCIPDBI.geneta

Genetic ablation of VIAAT in glycinergic neurons causes a severe respiratory phenotype and perinatal death - Rahman, Jamilur; Besser, Stefanie; Schnell, Christian; Eulenburg, Volker; Hirrlinger, Johannes; Wojcik, Sonja M; Huelsmann, Swen (Brain Structure & Function, 2015)
Both glycinergic and GABAergic neurons require the vesicular inhibitory amino acid transporter (VIAAT) for synaptic vesicle filling. Presynaptic GABA concentrations are determined by the GABA-synthesizing enzymes glutamate decarboxylase (GAD)65 and GAD67, whereas the presynaptic glycine content depends on the plasma membrane glycine transporter 2 (GlyT2). Although severely impaired, glycinergic transmission is not completely absent in GlyT2-knockout mice, suggesting that other routes of glycine uptake or de novo synthesis of glycine exist in presynaptic terminals. To investigate the consequences of a complete loss of glycinergic transmission, we generated a mouse line with a conditional ablation of VIAAT in glycinergic neurons by crossing mice with loxP-flanked VIAAT alleles with a GlyT2-Cre transgenic mouse line. Interestingly, conditional VIAAT knockout (VIAAT cKO) mice were not viable at birth. In addition to the dominant respiratory failure, VIAAT cKO showed an umbilical hernia and a cleft palate. Immunohistochemistry revealed an almost complete depletion of VIAAT in the brainstem. Electrophysiology revealed the absence of both spontaneous glycinergic and GABAergic inhibitory postsynaptic currents from hypoglossal motoneurons. Our results demonstrate that the deletion of VIAAT in GlyT2-Cre expressing neurons also strongly affects GABAergic transmission and suggest a large overlap of the glycinergic and the GABAergic neuron population during early development in the caudal parts of the brai
EVALuna2:4703

Genetically Single Generation and characterization of an endogenously tagged SPG11-human iPSC line by CRISPR/Cas9 mediated knock-in - Krumm, Laura; Pozner, Tatyana; Kaindl, Johanna; Regensburger, Martin; Günther, Claudia; Turan, Sören; Asadollahi, Reza; Rauch, Anita; Winner, Beate (Stem Cell Research, 2021)
Pathogenic bi-allelic variants in the SPG11 gene result in rare motor neuron disorders such as Hereditary Spastic Paraplegia type 11, Charcot-Marie Tooth, and Juvenile Amyotrophic Lateral Sclerosis-5. The main challenge in SPG11-linked disease research is the lack of antibodies against SPG11 encoded spatacsin. Here, we describe the CRISPR/Cas9 mediated generation and validation of an endogenously tagged SPG11- human iPSC line that contains an HA tag at the C-terminus of SPG11. The line exhibits multi-lineage differentiation potential and holds promise for studying the role of spatacsin and for the elucidation of SPG11-associated pathogenesis.
CRIS-Team Scopus Importer:2021-09-10

Genetic evidence that Nkx2.2 and Pdgfra are major determinants of the timing of oligodendrocyte differentiation in the developing CNS - Zhu, Qiang; Zhao, Xiaofeng; Zheng, Kang; Li, Hong; Huang, Hao; Zhang, Zunyi; Mastracci, Teresa; Wegner, Michael; Chen, Yiping; Sussel, Lori; Qiu, Mengsheng (Development, 2014)
In the central nervous system (CNS), oligodendrocyte maturation and axonal myelination occur on a predictable schedule, but the underlying timing mechanisms are largely unknown. In the present study, we demonstrate that Nkx2.2 homeodomain transcription factor is a key regulator for the timing of oligodendrocyte differentiation during development. Whereas induced expression of Nkx2.2 in early oligodendrocyte precursor cells (OPCs) causes precocious differentiation of oligodendrocytes, conditional ablation of Nkx2.2 temporally delays oligodendrocyte maturation. Moreover, Nkx2.2 can directly bind to the promoter of platelet-derived growth factor receptor alpha (Pdgfra) and repress its gene expression. Genetic ablation of Pdgfra mimics the effect of Nkx2.2 overexpression in accelerating OPC differentiation in the developing spinal cord. Together, our findings strongly suggest that Nkx2.2 functions as a major 'switch' to turn off Pdgfra signaling in OPCs and initiate the intrinsic program for oligodendrocyte differentiation.
EVALuna2:4964

Genetic screening confirms heterozygous mutations in ACAN as a major cause of idiopathic short stature - Hauer, Nadine; Sticht, Heinrich; Boppudi, Sangamitra; Büttner, Christian; Kraus, Cornelia; Trautmann, Udo; Zenker, Martin; Zweier, Christiane; Wiesener, Antje; Abou Jamra, Rami; Wieczorek, Dagmar; Kelkel, Jaqueline; et al. (Scientific Reports, 2017)
Short stature is a common pediatric disorder affecting 3% of the population. However, the clinical variability and genetic heterogeneity prevents the identification of the underlying cause in about 80% of the patients. Recently, heterozygous mutations in the ACAN gene coding for the proteoglycan aggrecan, a main component of the cartilage matrix, were associated with idiopathic short stature. To ascertain the prevalence of ACAN mutations and broaden the phenotypic spectrum in patients with idiopathic short stature we performed sequence analyses in 428 families. We identified heterozygous nonsense mutations in four and potentially disease-causing missense variants in two families (1.4%). These patients presented with a mean of -3.2 SDS and some suggestive clinical characteristics. The results suggest heterozygous mutations in ACAN as a common cause of isolated as well as inherited idiopathic short stature.
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Genome-wide association study of L-arginine and dimethylarginines reveals novel metabolic pathway for symmetric dimethylarginine - Lueneburg, Nicole; Lieb, Wolfgang; Zeller, Tanja; Chen, Ming-Huei; Maas, Renke; Carter, Angela M.; Xanthakis, Vanessa; Glazer, Nicole L.; Schwedhelm, Edzard; Seshadri, Sudha; Ikram, Mohammad Arfan; Longstreth, William T.; et al. (Circulation-Cardiovascular Genetics, 2014)
Dimethylarginines (DMA) interfere with nitric oxide formation by inhibiting nitric oxide synthase (asymmetrical DMA [ADMA]) and l-arginine uptake into the cell (ADMA and symmetrical DMA [SDMA]). In prospective clinical studies, ADMA has been characterized as a cardiovascular risk marker, whereas SDMA is a novel marker for renal function and associated with all-cause mortality after ischemic stroke. The aim of the current study was to characterize the environmental and genetic contributions to interindividual variability of these biomarkers.This study comprised a genome-wide association analysis of 3 well-characterized population-based cohorts (Framingham Heart Study [FHS; n=2992], Gutenberg Health Study [GHS; n=4354], and Multinational Monitoring of Trends and Determinants in Cardiovascular Disease Study [MONICA]/Cooperative Health Research in the Augsburg Area, Augsburg, Bavaria, Germany [KORA] F3 [n=581]) and identified replicated loci (DDAH1, MED23, Arg1, and AGXT2) associated with the interindividual variability in ADMA, l-arginine, and SDMA. Experimental in silico and in vitro studies confirmed functional significance of the identified AGXT2 variants. Clinical outcome analysis in 384 patients of the Leeds stroke study demonstrated an association between increased plasma levels of SDMA, AGXT2 variants, and various cardiometabolic risk factors. AGXT2 variants were not associated with poststroke survival in the Leeds study or were they associated with incident stroke in the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium.These genome-wide association study support the importance of DDAH1 and MED23/Arg1 in regulating ADMA and l-arginine metabolism, respectively, and identify a novel regulatory renal pathway for SDMA by AGXT2. AGXT2 variants might explain part of the pathogenic link between SDMA, renal function, and outcome. An association between AGXT2 variants and stroke is unclear and warrants further investigation.
EVALuna2:8688

Genotype-phenotype correlations in RHOBTB2-associated neurodevelopmental disorders - Langhammer, Franziska; Maroofian, Reza; Badar, Rueda; Gregor, Anne; Rochman, Michelle; Ratliff, Jeffrey B.; Koopmans, Marije; Herget, Theresia; Hempel, Maja; Kortüm, Fanny; Heron, Delphine; Mignot, Cyril; et al. (Genetics in Medicine, 2023)
Purpose: Missense variants clustering in the BTB domain region of RHOBTB2 cause a developmental and epileptic encephalopathy with early-onset seizures and severe intellectual disability. Methods: By international collaboration, we assembled individuals with pathogenic RHOBTB2 variants and a variable spectrum of neurodevelopmental disorders. By western blotting, we investigated the consequences of missense variants in vitro. Results: In accordance with previous observations, de novo heterozygous missense variants in the BTB domain region led to a severe developmental and epileptic encephalopathy in 16 individuals. Now, we also identified de novo missense variants in the GTPase domain in 6 individuals with apparently more variable neurodevelopmental phenotypes with or without epilepsy. In contrast to variants in the BTB domain region, variants in the GTPase domain do not impair proteasomal degradation of RHOBTB2 in vitro, indicating different functional consequences. Furthermore, we observed biallelic splice-site and truncating variants in 9 families with variable neurodevelopmental phenotypes, indicating that complete loss of RHOBTB2 is pathogenic as well. Conclusion: By identifying genotype-phenotype correlations regarding location and consequences of de novo missense variants in RHOBTB2 and by identifying biallelic truncating variants, we further delineate and expand the molecular and clinical spectrum of RHOBTB2-related phenotypes, including both autosomal dominant and recessive neurodevelopmental disorders.
CRIS-Team Scopus Importer:2023-06-30
Keywords: Developmental and epileptic encephalopathy; Intellectual disability; Neurodevelopmental disorder; RHOBTB2; Seizures

Genotype-phenotype evaluation of MED13L defects in the light of a novel truncating and a recurrent missense mutation - Asadollahi, Reza; Zweier, Markus; Gogoll, Laura; Schiffmann, Raphael; Sticht, Heinrich; Steindl, Katharina; Rauch, Anita (European Journal of Medical Genetics, 2017)
A decade after the designation of MED13L as a gene and its link to intellectual disability (ID) and dextro-looped transposition of great arteries in 2003, we previously described a recognizable syndrome due to MED13L haploinsufficiency. Subsequent reports of 22 further patients diagnosed by genome-wide testing further delineated the syndrome with expansion of the phenotypic spectrum and showed reduced penetrance for congenital heart defects. We now report two novel patients identified by whole exome sequencing, one with a de novo MED13L truncating mutation and the other with a de novo missense mutation. The first patient indicates some facial resemblance to Kleefstra syndrome as a novel differential diagnosis, and the second patient shows, for the first time, recurrence of a MED13L missense mutation (p.(Asp860Gly)). Notably, our in silico modelling predicted this missense mutation to decrease the stability of an alpha-helix and thereby affecting the MED13L secondary structure, while the majority of published missense mutations remain variants of uncertain significance. Review of the reported patients with MED13L haploinsufficiency indicates moderate to severe ID and facial anomalies in all patients, as well as severe speech delay and muscular hypotonia in the majority. Further common signs include abnormal MRI findings of myelination defects and abnormal corpus callosum, ataxia and coordination problems, autistic features, seizures/abnormal EEG, or congenital heart defects, present in about 20-50% of the patients. With reference to facial anomalies, the majority of patients were reported to show broad/prominent forehead, low set ears, bitemporal narrowing, upslanting palpebral fissures, depressed/flat nasal bridge, bulbous nose, and abnormal chin, but macroglossia and horizontal eyebrows were also observed in ∼30%. The latter are especially important in the differential diagnosis of 1p36 deletion and Kleefstra syndromes, while the more common facial gestalt shows some resemblance to 22q11.2 deletion syndrome. Despite the fact that MED13L was found to be one of the most common ID genes in the Deciphering Developmental Disorders Study, further detailed patient descriptions are needed to explore the full clinical spectrum, potential genotype-phenotype correlations, as well as the role of missense mutations and potential mutational hotspots along the gene.
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Glial but not neuronal development in the cochleo-vestibular ganglion requires Sox10. - Stolt, Claus; Wegner, Michael; et al. (Journal of Neurochemistry, 2010)
The cochleo-vestibular ganglion contains neural crest-derived glial cells and sensory neurons that are derived from the neurogenic otic placode. Little is known about the molecular mechanisms that regulate the tightly orchestrated development of this structure. Here, we report that Sox10, a high-mobility group DNA-binding domain transcription factor that is required for the proper development of neural crest cell derivatives, is specifically expressed in post-migratory neural crest cells in the cochleo-vestibular ganglion. Using Sox10-deficient mice, we demonstrate that this transcription factor is essential for the survival, but not the generation, of the post-migratory neural crest cells within the inner ear. In the absence of these neural crest-derived cells, we have investigated the survival of the otocyst-derived auditory neurons. Surprisingly, auditory neuron differentiation, sensory target innervation and survival are conserved despite the absence of glial cells. Moreover, brain-derived neurotrophic factor expression is increased in the hair cells of Sox10-deficient mice, a compensatory mechanism that may prevent spiral ganglion neuronal cell death. Taken together, these data suggest that in the absence of neural crest-derived glial cells, an increase trophic support from hair cells promotes the survival of spiral ganglion neurons in Sox10 mutant mice. © 2010 International Society for Neurochemistry.
UnivIS-Import:2015-03-09:Pub.2010.med.IB.LPCIPDBI.glialb
Keywords: auditory neurons; development; glial cells; inner ear; neural crest cells; Sox genes

Glucose transporter isoform 1 expression enhances metastasis of malignant melanoma cells - Koch, Andreas; Lang, Sven Arke; Wild, Peter Johannes; Gantner, Susanne; Mahli, Abdo; Spanier, Gerrit; Berneburg, Mark; Mueller, Martina; Boßerhoff, Anja Katrin; Hellerbrand, Claus (Oncotarget, 2015)
The glucose transporter isoform 1 (GLUT1; SLC2A1) is a key rate-limiting factor in the transport of glucose into cancer cells. Enhanced GLUT1 expression and accelerated glycolysis have been found to promote aggressive growth in a range of tumor entities. However, it was unknown whether GLUT1 directly impacts metastasis. Here, we aimed at analyzing the expression and function of GLUT1 in malignant melanoma. Immunohistochemical analysis of 78 primary human melanomas on a tissue micro array showed that GLUT1 expression significantly correlated with the mitotic activity and a poor survival. To determine the functional role of GLUT1 in melanoma, we stably suppressed GLUT1 in the murine melanoma cell line B16 with shRNA. GLUT1 suppressed melanoma cells revealed significantly reduced proliferation, apoptosis resistance, migratory activity and matrix metalloproteinase 2 (MMP2) expression. In a syngeneic murine model of hepatic metastasis, GLUT1-suppressed cells formed significantly less metastases and showed increased apoptosis compared to metastases formed by control cells. Treatment of four different human melanoma cell lines with a pharmacological GLUT1 inhibitor caused a dose-dependent reduction of proliferation, apoptosis resistance, migratory activity and MMP2 expression. Analysis of MAPK signal pathways showed that GLUT1 inhibition significantly decreased JNK activation, which regulates a wide range of targets in the metastatic cascade. In summary, our study provides functional evidence that enhanced GLUT1 expression in melanoma cells favors their metastatic behavior. These findings specify GLUT1 as an attractive therapeutic target and prognostic marker for this highly aggressive tumor.
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Glutamate residue 90 in the predicted transmembrane domain 2 is crucial for cation flux through channelrhodopsin 2 - Ruffert, Karelia; Himmel, Bettina; Lall, Deepti; Bamann, Christian; Bamberg, Ernst; Betz, Heinrich; Eulenburg, Volker (Biochemical and Biophysical Research Communications, 2011)
Channelrhodopsin 2 (ChR2) is a microbial-type rhodopsin with a putative heptahelical structure that binds all-trans-retinal. Blue light illumination of ChR2 activates an intrinsic leak channel conductive for cations. Sequence comparison of ChR2 with the related ChR1 protein revealed a cluster of charged amino acids within the predicted transmembrane domain 2 (TM2), which includes glutamates E90, E97 and E101. Charge inversion substitutions of these residues significantly altered ChR2 function as revealed by two-electrode voltage-clamp recordings of light-induced currents from Xenopus laevis oocytes expressing the respective mutant proteins. Specifically, replacement of E90 by lysine or alanine resulted in differential effects on H(+)- and Na(+)-mediated currents. Our results are consistent with this glutamate side chain within the proposed TM2 contributing to ion flux through and the cation selectivity of ChR2.
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Glycine ReceptorAutoantibodies Impair Receptor Function and Induce Motor Dysfunction - Rauschenberger, Vera; Von Wardenburg, Niels; Schaefer, Natascha; Ogino, Kazutoyo; Hirata, Hiromi; Lillesaar, Christina; Kluck, Christoph; Meinck, Hans-Michael; Borrmann, Marc; Weishaupt, Andreas; Doppler, Kathrin; Wickel, Jonathan; et al. (Annals of Neurology, 2020)
Objective Impairment of glycinergic neurotransmission leads to complex movement and behavioral disorders. Patients harboring glycine receptor autoantibodies suffer from stiff-person syndrome or its severe variant progressive encephalomyelitis with rigidity and myoclonus. Enhanced receptor internalization was proposed as the common molecular mechanism upon autoantibody binding. Although functional impairment of glycine receptors following autoantibody binding has recently been investigated, it is still incompletely understood. Methods A cell-based assay was used for positive sample evaluation. Glycine receptor function was assessed by electrophysiological recordings and radioligand binding assays. The in vivo passive transfer of patient autoantibodies was done using the zebrafish animal model. Results Glycine receptor function as assessed by glycine dose-response curves showed significantly decreased glycine potency in the presence of patient sera. Upon binding of autoantibodies from 2 patients, a decreased fraction of desensitized receptors was observed, whereas closing of the ion channel remained fast. The glycine receptor N-terminal residues(29)A to(62)G were mapped as a common epitope of glycine receptor autoantibodies. An in vivo transfer into the zebrafish animal model generated a phenotype with disturbed escape behavior accompanied by a reduced number of glycine receptor clusters in the spinal cord of affected animals. Interpretation Autoantibodies against the extracellular domain mediate alterations of glycine receptor physiology. Moreover, our in vivo data demonstrate that the autoantibodies are a direct cause of the disease, because the transfer of human glycine receptor autoantibodies to zebrafish larvae generated impaired escape behavior in the animal model compatible with abnormal startle response in stiff-person syndrome or progressive encephalitis with rigidity and myoclonus patients. ANN NEUROL 2020
CRIS-Team WoS Importer:2020-07-31

Glycine receptor autoantibody binding to the extracellular domain is independent from receptor glycosylation - Rauschenberger, Vera; Piro, Inken; Kasaragod, Vikram Babu; Hoerlin, Verena; Eckes, Anna-Lena; Kluck, Christoph; Schindelin, Hermann; Meinck, Hans-Michael; Wickel, Jonathan; Geis, Christian; Tuzun, Erdem; Doppler, Kathrin; et al. (Frontiers in Molecular Neuroscience, 2023)
Glycine receptor (GlyR) autoantibodies are associated with stiff-person syndrome and the life-threatening progressive encephalomyelitis with rigidity and myoclonus in children and adults. Patient histories show variability in symptoms and responses to therapeutic treatments. A better understanding of the autoantibody pathology is required to develop improved therapeutic strategies. So far, the underlying molecular pathomechanisms include enhanced receptor internalization and direct receptor blocking altering GlyR function. A common epitope of autoantibodies against the GlyRα1 has been previously defined to residues 1A-33G at the N-terminus of the mature GlyR extracellular domain. However, if other autoantibody binding sites exist or additional GlyR residues are involved in autoantibody binding is yet unknown. The present study investigates the importance of receptor glycosylation for binding of anti-GlyR autoantibodies. The glycine receptor α1 harbors only one glycosylation site at the amino acid residue asparagine 38 localized in close vicinity to the identified common autoantibody epitope. First, non-glycosylated GlyRs were characterized using protein biochemical approaches as well as electrophysiological recordings and molecular modeling. Molecular modeling of non-glycosylated GlyRα1 did not show major structural alterations. Moreover, non-glycosylation of the GlyRα1N38Q did not prevent the receptor from surface expression. At the functional level, the non-glycosylated GlyR demonstrated reduced glycine potency, but patient GlyR autoantibodies still bound to the surface-expressed non-glycosylated receptor protein in living cells. Efficient adsorption of GlyR autoantibodies from patient samples was possible by binding to native glycosylated and non-glycosylated GlyRα1 expressed in living not fixed transfected HEK293 cells. Binding of patient-derived GlyR autoantibodies to the non-glycosylated GlyRα1 offered the possibility to use purified non-glycosylated GlyR extracellular domain constructs coated on ELISA plates and use them as a fast screening readout for the presence of GlyR autoantibodies in patient serum samples. Following successful adsorption of patient autoantibodies by GlyR ECDs, binding to primary motoneurons and transfected cells was absent. Our results indicate that the glycine receptor autoantibody binding is independent of the receptor’s glycosylation state. Purified non-glycosylated receptor domains harbouring the autoantibody epitope thus provide, an additional reliable experimental tool besides binding to native receptors in cell-based assays for detection of autoantibody presence in patient sera.
CRIS-Team Scopus Importer:2023-03-17
Keywords: adsorption; autoantibodies; extracellular domain; glycine receptor; glycosylation

Glycine receptor mouse mutants: model systems for human hyperekplexia - Schaefer, Natascha; Langlhofer, Georg; Kluck, Christoph; Villmann, Carmen (British Journal of Pharmacology, 2013)
Human hyperekplexia is a neuromotor disorder caused by disturbances in inhibitory glycine-mediated neurotransmission. Mutations in genes encoding for glycine receptor subunits or associated proteins, such as GLRA1, GLRB, GPHN and ARHGEF9, have been detected in patients suffering from hyperekplexia. Classical symptoms are exaggerated startle attacks upon unexpected acoustic or tactile stimuli, massive tremor, loss of postural control during startle and apnoea. Usually patients are treated with clonazepam, this helps to dampen the severe symptoms most probably by up-regulating GABAergic responses. However, the mechanism is not completely understood. Similar neuromotor phenotypes have been observed in mouse models that carry glycine receptor mutations. These mouse models serve as excellent tools for analysing the underlying pathomechanisms. Yet, studies in mutant mice looking for postsynaptic compensation of glycinergic dysfunction via an up-regulation in GABAA receptor numbers have failed, as expression levels were similar to those in wild-type mice. However, presynaptic adaptation mechanisms with an unusual switch from mixed GABA/glycinergic to GABAergic presynaptic terminals have been observed. Whether this presynaptic adaptation explains the improvement in symptoms or other compensation mechanisms exist is still under investigation. With the help of spontaneous glycine receptor mouse mutants, knock-in and knock-out studies, it is possible to associate behavioural changes with pharmacological differences in glycinergic inhibition. This review focuses on the structural and functional characteristics of the various mouse models used to elucidate the underlying signal transduction pathways and adaptation processes and describes a novel route that uses gene-therapeutic modulation of mutated receptors to overcome loss of function mutations.
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Glycine receptor mutants of the mouse: what are possible routes of inhibitory compensation? - Schäfer, Natascha; Vogel, Nicolas; Villmann, Carmen (Frontiers in Molecular Neuroscience, 2012)
Defects in glycinergic inhibition result in a complex neuromotor disorder in humans known as hyperekplexia (OMIM 149400) with similar phenotypes in rodents characterized by an exaggerated startle reflex and hypertonia. Analogous to genetic defects in humans single point mutations, microdeletions, or insertions in the Glra1 gene but also in the Glrb gene underlie the pathology in mice. The mutations either localized in the ? (spasmodic, oscillator, cincinnati, Nmf11) or the ? (spastic) subunit of the glycine receptor (GlyR) are much less tolerated in mice than in humans, leaving the question for the existence of different regulatory elements of the pathomechanisms in humans and rodents. In addition to the spontaneous mutations, new insights into understanding of the regulatory pathways in hyperekplexia or glycine encephalopathy arose from the constantly increasing number of knock-out as well as knock-in mutants of GlyRs. Over the last five years, various efforts using in vivo whole cell recordings provided a detailed analysis of the kinetic parameters underlying glycinergic dysfunction. Presynaptic compensation as well as postsynaptic compensatory mechanisms in these mice by other GlyR subunits or GABA(A) receptors, and the role of extra-synaptic GlyRs is still a matter of debate. A recent study on the mouse mutant oscillator displayed a novel aspect for compensation of functionality by complementation of receptor domains that fold independently. This review focuses on defects in glycinergic neurotransmission in mice discussed with the background of human hyperekplexia en route to strategies of compensation.
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Glycine transporter GlyT1, but not GlyT2, is expressed in rat dorsal root ganglion–Possible implications for neuropathic pain - Schloesser, Lukas; Barthel, Franziska; Brandenburger, Timo; Neumann, Elena; Bauer, Inge; Eulenburg, Volker; Werdehausen, Robert; Hermanns, Henning (Neuroscience Letters, 2015)
Glycinergic inhibitory neurotransmission plays a pivotal role in the development of neuropathic pain. The glycine concentration in the synaptic cleft is controlled by the glycine transporters GlyT1 and GlyT2. GlyT1 is expressed throughout the central nervous system, while GlyT2 is exclusively located in glycinergic neurons. Aim of the present study was to investigate whether GlyTs are also expressed in the peripheral sensory nervous system and whether their expression is modulated in experimental neuropathic pain. Neuropathic pain was induced in male Wistar rats by Chronic Constriction Injury (CCI) and verified by assessment of mechanical allodynia (von Frey method). Expression patterns of GlyTs and the glycine binding subunit NR1 of the N-methyl-d-aspartate (NMDA) receptor in the spinal cord and dorsal root ganglia (DRG) were analyzed by Western blot analysis, PCR and immunohistochemistry. While both GlyT1 and GlyT2 were detected in the spinal cord, only GlyT1, but not GlyT2, was detected in DRG. Immunofluorescence revealed a strictly neuronal localization of GlyT1 and a co-localization of GlyT1 and NR1 in DRG. Compared to sham procedure, spinal cord and DRG expression of GlyT1 was not altered and NR1 was unchanged in DRG 12 days after CCI. GlyT1, but not GlyT2, is expressed in the peripheral sensory nervous system. The co-expression of GlyT1 and NMDA receptors in DRG suggests that GlyT1 regulates glycine concentration at the glycine binding site of the NMDA receptor. Differential regulation of GlyT1 expression in the spinal cord or DRG, however, does not seem to be associated with the development of neuropathic pain.
EVALuna2:4725

GlyT1 determines the glycinergic phenotype of amacrine cells in the mouse retina - Eulenburg, Volker; Knop, Gabriel; Sedmak, Tina; Schuster, Stefanie; Hauf, Katharina; Schneider, Julia; Feigenspan, Andreas; Joachimsthaler, Anneka; Brandstätter, Johann Helmut (Brain Structure & Function, 2018)
The amino acid glycine acts as a neurotransmitter at both inhibitory glycinergic and excitatory glutamatergic synapses predominantly in caudal regions of the central nervous system but also in frontal brain regions and the retina. After its presynaptic release and binding to postsynaptic receptors at caudal glycinergic synapses, two high-affinity glycine transporters GlyT1 and GlyT2 remove glycine from the extracellular space. Glycinergic neurons express GlyT2, which is essential for the presynaptic replenishment of the transmitter, while glial-expressed GlyT1 was shown to control the extracellular glycine concentration. Here we show that GlyT1 expressed by glycinergic amacrine cells of the retina does not only contribute to the control of the extracellular glycine concentration in the retina but is also essential for the maintenance of the glycinergic transmitter phenotype of this cell population. Specifically, loss of GlyT1 from the glycinergic AII amacrine cells impairs AII-mediated glycinergic neurotransmission and alters regulation of the extracellular glycine concentration, without changes in the overall distribution and/or size of glycinergic synapses. Taken together, our results suggest that GlyT1 expressed by amacrine cells in the retina combines functions covered by neuronal GlyT2 and glial GlyT1 at caudal glycinergic synapses.
EVALuna2:35241

GlyT1 encephalopathy: Characterization of presumably disease causing GlyT1 mutations - Hauf, K.; Barsch, L.; Bauer, D.; Buchert, R.; Armbruster, Anja; Frauenfeld, L.; Grasshoff, U.; Eulenburg, V. (Neurochemistry International, 2020)
Glycine constitutes a major inhibitory neurotransmitter predominantly in caudal regions of the CNS. The extracellular glycine concentration is regulated synergistically by two high affinity, large capacity transporters GlyT1 and GlyT2. Both proteins are encoded by single genes SLC6A9 and SLC6A5, respectively. Mutations within the SLC6A5 gene encoding for GlyT2 have been demonstrated to be causative for hyperekplexia (OMIM #614618), a complex neuromuscular disease, in humans. In contrast, mutations within the SLC6A9 gene encoding for GlyT1 have been associated with GlyT1 encephalopathy (OMIM #601019), a disease causing severe postnatal respiratory deficiency, muscular hypotonia and arthrogryposis. The consequences of the respective GlyT1 mutations on the function of the transporter protein, however, have not yet been analysed. In this study we present the functional characterisation of three previously published GlyT1 mutations, two mutations predicted to cause truncation of GlyT1 (GlyT1Q573* and GlyT1K310F+fs*31) and one predicted to cause an amino acid exchange within transmembrane domain 7 of the transporter (GlyT1S407G), that are associated with GlyT1 encephalopathy. Additionally, the characterization of a novel mutation predicted to cause an amino acid exchange within transmembrane domain 1 (GlyT1V118M) identified in two fetuses showing increased nuchal translucency and arthrogryposis in routine ultrasound scans is demonstrated. We show that in recombinant systems the two presumably truncating mutations resulted in an intracellular retained GlyT1 protein lacking the intracellular C-terminal domain. In both cases this truncated protein did not show any residual transport activity. The point mutations, hGlyT1S407G and hGlyT1V118M, were processed correctly, but showed severely diminished activity, thus constituting a functional knock-out in-vivo. Taken together our data demonstrate that all analysed mutations of GlyT1 that have been identified in GlyT1 encephalopathy patients cause severe impairment of transporter function. This is consistent with the idea that loss of GlyT1 function is indeed causal for the disease phenotype.
CRIS-Team Scopus Importer:2020-08-07
Keywords: Encephalopathy; Glycine; GlyT1; Neurotransmitter; Transporter

Group I metabotropic glutamate receptors bind to protein phosphatase 1C: Mapping and modeling of interacting sequences. - Croci, Cristina; Sticht, Heinrich; Brandstätter, Johann Helmut; Enz, Ralf (Journal of Biological Chemistry, 2003)
The modulation of neurotransmitter receptors by kinases and phosphatases represents a key mechanism in controlling synaptic signal transduction. However, molecular determinants involved in the specific targeting and interactions of these enzymes are largely unknown. Here, we identified both catalytic γ-isoforms of protein phosphatase 1C (PP1γ1 and PP1γ2) as binding partners of the group I metabotropic glutamate receptors type 1a, 5a, and 5b in yeast cells and pull-down assays, using recombinant and native protein preparations. The tissue distribution of interacting proteins was compared, and protein phosphatase 1C was detected in dendrites of retinal bipolar cells expressing the respective interacting glutamate receptors. We mapped interacting domains within binding partners and identified five amino acids in the intracellular C termini of the metabotropic glutamate receptors type 1a, 5a, 5b, and 7b being both necessary and sufficient to bind protein phosphatase 1C. Furthermore, we show a dose-dependent competition of these C termini in binding the enzyme. Based on our data, we investigated the structure of the identified amino acids bound to protein phosphatase 1C by homology-based molecular modeling. In summary, these results provide a molecular description of the interaction between protein phosphatase 1C and metabotropic glutamate receptors and thereby increase our understanding of glutamatergic signal transduction.
UnivIS-Import:2015-04-14:Pub.2003.med.IB.profes_1.groupi