H2B monoubiquitination is essential for peripheral myelination and guided by Egr2 in Schwann cells - Wüst, Hannah; Wegener, Amelie; Fröb, Franziska; Hartwig, Anna; Wegwitz, F.; Kari, V. L.; Schimmel, M.; Tamm, E. R.; Johnsen, S. A.; Wegner, Michael; Sock, Elisabeth (GLIA, 2021)
CRIS-Team WoS Importer:2021-07-16

Haemoglobin and vascular function in the human retinal vascular bed - Ritt, Martin; Harazny, Joanna M.; Schmidt, Stefan; Raff, Ulrike; Ott, Christian; Michelson, Georg; Schmieder, Roland (Journal of Hypertension, 2013)
: Haemoglobin is a potential nitric oxide (NO) scavenger. Haemoglobin is associated with blood viscosity and the red blood cell free layer width of microvessels that impact on shear stress in the microcirculation. We hypothesized that haemoglobin modulates retinal vascular function.: In 139 nondiabetic male patients with haemoglobin levels within the normal range, the vasodilatatory response of retinal capillary blood flow (RCF) to flicker light exposure and the vasoconstrictor response of RCF to infusion of NO synthase inhibitor N-monomethyl-L-arginine (L-NMMA) were assessed. The latter, because of the selective nature of L-NMMA, reflects a parameter of basal NO activity of retinal vasculature. Examinations of retinal parameters were performed noninvasively and in vivo using scanning laser Doppler flowmetry.: Patients with haemoglobin greater or equal the median revealed reduced increase of RCF to flicker light exposure (2.83 ± 12 vs. 9.52 ± 14 (%), P adjusted = 0.002), and greater decrease of RCF to L-NMMA infusion (-7.35 ± 13 vs. -0.92 ± 14 (%), P adjusted = 0.008), compared with patients with haemoglobin below the median. Haemoglobin was negatively related to the percentage change of RCF to flicker light exposure (r = -0.249, P = 0.004) and to L-NMMA infusion (r = -0.201, P = 0.018). In multiple linear regression analysis haemoglobin was an independent determinant of the percentage change of RCF to flicker light exposure (model 1: ß = -0.278, P = 0.003 and model 2: ß = -0.283, P = 0.002) and to L-NMMA infusion (model 1: ß = -0.256, P = 0.005 and model 2: ß = -0.269, P = 0.004).: Haemoglobin emerged as an independent determinant of vascular function in the human retinal vascular bed.
EVALuna2:3613

Haploinsufficiency of vascular endothelial growth factor related signaling genes is associated with tetralogy of Fallot - Reuter, Miriam S.; Jobling, Rebekah; Chaturvedi, Rajiv R.; Manshaei, Roozbeh; Costain, Gregory; Heung, Tracy; Curtis, Meredith; Hosseini, S. Mohsen; Liston, Eriskay; Lowther, Chelsea; Oechslin, Erwin; Sticht, Heinrich; et al. (Genetics in Medicine, 2019)
Purpose: To determine disease-associated single-gene variants in conotruncal defects, particularly tetralogy of Fallot (TOF).
CRIS-Team WoS Importer:2019-04-25

Having it both ways: Sox protein function between conservation and innovation. - Wegner, Michael; et al. (Cellular and Molecular Life Sciences, 2008)
Transcription factors of the Sox family arose around the advent of multicellularity in animals, arguing that their ability to regulate the expression of extracellular matrix, cell adhesion and signaling molecules may have been instrumental in the generation of metazoans. In particular, during vertebrate evolution, the Sox family experienced a phase of expansion that led to the appearance of groups of highly homologous Sox proteins and the division of existing Sox protein functions among group members. It furthermore allowed Sox transcription factors to acquire numerous novel functions. These past events of subfunctionalization and neofunctionalization can still be recognized today in all groups of the Sox family. They have led to partial functional redundancies, but also to interesting species-specific variations in the developmental roles of Sox proteins as shown here for the SoxB and the SoxE groups. © 2008 Birkhaueser.
UnivIS-Import:2015-03-09:Pub.2008.med.IB.LPCIPDBI.having
Keywords: Evolution; High-mobility-group; Multicellularity; Redundancy; Sox; Speciesspecificity; Sry; Transcription factor

HDAC2 Is Involved in the Regulation of BRN3A in Melanocytes and Melanoma - Heppt, Markus; Wessely, Anja; Hornig, Eva; Kammerbauer, Claudia; Graf, Saskia A.; Besch, Robert; French, Lars E.; Matthies, Alexander Oliver; Kuphal, Silke; Kappelmann-Fenzl, Melanie; Boßerhoff, Anja Katrin; Berking, Carola (International Journal of Molecular Sciences, 2022)
The neural crest transcription factor BRN3A is essential for the proliferation and survival of melanoma cells. It is frequently expressed in melanoma but not in normal melanocytes or benign nevi. The mechanisms underlying the aberrant expression of BRN3A are unknown. Here, we investigated the epigenetic regulation of BRN3A in melanocytes and melanoma cell lines treated with DNA methyltransferase (DNMT), histone acetyltransferase (HAT), and histone deacetylase (HDAC) inhibitors. DNMT and HAT inhibition did not significantly alter BRN3A expression levels, whereas panHDAC inhibition by trichostatin A led to increased expression. Treatment with the isoform-specific HDAC inhibitor mocetinostat, but not with PCI-34051, also increased BRN3A expression levels, suggesting that class I HDACs HDAC1, HDAC2, and HDAC3, and class IV HDAC11, were involved in the regulation of BRN3A expression. Transient silencing of HDACs 1, 2, 3, and 11 by siRNAs revealed that, specifically, HDAC2 inhibition was able to increase BRN3A expression. ChIP-Seq analysis uncovered that HDAC2 inhibition specifically increased H3K27ac levels at a distal enhancer region of the BRN3A gene. Altogether, our data suggest that HDAC2 is a key epigenetic regulator of BRN3A in melanocytes and melanoma cells. These results highlight the importance of epigenetic mechanisms in regulating melanoma oncogenes.
CRIS-Team Scopus Importer:2022-02-04
Keywords: BRN3A; ChIP-Seq; DNA methylation; Epigenetic regulation; HAT; HDAC; Melanoma

HDAC2 is involved in the regulation of Brn3a in melanocytes and melanoma - Heppt, Markus; Wessely, Anja; Hornig, E.; Kammerbauer, C.; Graf, S.; Besch, R.; French, L. E.; Kuphal, Silke; Kappelmann-Fenzl, Melanie; Boßerhoff, Anja Katrin; Berking, Carola (EXPERIMENTAL DERMATOLOGY, 2023)
CRIS-Team WoS Importer:2023-06-02

Hepatic steatosis potentiates irinotecan-induced hepatocellular injury via dysregulation of irinotecan-metabolizing enzymes - Mahli, Abdo; Koch, Angelika; Thasler, W.; Hellerbrand, Claus (JOURNAL OF HEPATOLOGY, 2018)
CRIS-Team WoS Importer:2019-03-26

Hepatocellular carcinoma cells surviving doxorubicin treatment exhibit increased migratory potential and resistance to doxorubicin re-treatment in vitro - Buschauer, Sebastian; Koch, Andreas; Wiggermann, Philipp; Mueller, Martina; Hellerbrand, Claus (Oncology Letters, 2018)
Transarterial chemoembolization (TACE) is an established therapeutic approach for the treatment of hepatocellular carcinoma (HCC). Although patients who undergo TACE may have prolonged survival, there are indications that the malignancy of residual HCC tissue can increase subsequent to the procedure. Although hypoxia, which occurs during TACE due to ischemia, is known to contribute to angiogenesis, little is known with regard to the undesirable effects of chemotherapeutic agents on residual HCC cells. Doxorubicin is one of the most commonly used drugs in TACE. The aim of the present study was to analyze alterations in Hep3B and HepG2 human HCC cell lines surviving doxorubicin treatment in vitro. Initially, the toxic concentration range was determined, and doxorubicin was subsequently applied in concentrations that killed >80% of the HCC cells. During the first days subsequent to treatment, surviving cells had higher expression levels of the epithelial-mesenchymal transition marker SNAIL, and exhibited increased migratory activity compared with control cells. At 3 weeks after the first doxorubicin treatment, surviving HCC cells tolerated significantly higher doxorubicin concentrations compared with control cells. As a potential explanation for this doxorubicin resistance, significantly increased mRNA expression levels of ATP-binding cassette ABCB1 (multidrug resistance protein 1) and ABCC1 (multidrug resistance-associated protein 1) were observed by reverse transcription-quantitative polymerase chain reaction. In summary, these findings indicate that, following TACE treatment, hypoxia as well as doxorubicin may induce a more malignant phenotype in surviving HCC cells and decrease susceptibility to further chemotherapeutic treatment.
EVALuna2:35811

Heterogeneity of Radial Glia-Like Cells in the Adult Hippocampus - Gebara, Elias; Bonaguidi, Michael Anthony; Beckervordersandforth, Ruth; Sultan, Sebastien; Udry, Florian; Gijs, Pieter-Jan; Lie, Dieter Chichung; Ming, Guo-Li; Song, Hongjun; Toni, Nicolas (Stem Cells, 2016)
Adult neurogenesis is tightly regulated by the neurogenic niche. Cellular contacts between niche cells and neural stem cells are hypothesized to regulate stem cell proliferation or lineage choice. However, the structure of adult neural stem cells and the contact they form with niche cells are poorly described. Here, we characterized the morphology of radial glia-like (RGL) cells, their molecular identity, proliferative activity, and fate determination in the adult mouse hippocampus. We found the coexistence of two morphotypes of cells with prototypical morphological characteristics of RGL stem cells: Type ? cells, which represented 76% of all RGL cells, displayed a long primary process modestly branching into the molecular layer and type ? cells, which represented 24% of all RGL cells, with a shorter radial process highly branching into the outer granule cell layer-inner molecular layer border. Stem cell markers were expressed in type ? cells and coexpressed with astrocytic markers in type ? cells. Consistently, in vivo lineage tracing indicated that type ? cells can give rise to neurons, astrocytes, and type ? cells, whereas type ? cells do not proliferate. Our results reveal that the adult subgranular zone of the dentate gyrus harbors two functionally different RGL cells, which can be distinguished by simple morphological criteria, supporting a morphofunctional role of their thin cellular processes. Type ? cells may represent an intermediate state in the transformation of type ?, RGL stem cells, into astrocytes.
EVALuna2:26338

Heterozygous and homozygous variants in STX1A cause a neurodevelopmental disorder with or without epilepsy - Luppe, Johannes; Sticht, Heinrich; Lecoquierre, Francois; Goldenberg, Alice; Gorman, Kathleen M.; Molloy, Ben; Agolini, Emanuele; Novelli, Antonio; Briuglia, Silvana; Kuismin, Outi; Marcelis, Carlo; Vitobello, Antonio; et al. (European Journal of Human Genetics, 2022)
The neuronal SNARE complex drives synaptic vesicle exocytosis. Therefore, one of its core proteins syntaxin 1A (STX1A) has long been suspected to play a role in neurodevelopmental disorders. We assembled eight individuals harboring ultra rare variants in STX1A who present with a spectrum of intellectual disability, autism and epilepsy. Causative variants comprise a homozygous splice variant, three de novo missense variants and two inframe deletions of a single amino acid. We observed a phenotype mainly driven by epilepsy in the individuals with missense variants in contrast to intellectual disability and autistic behavior in individuals with single amino acid deletions and the splicing variant. In silico modeling of missense variants and single amino acid deletions show different impaired protein-protein interactions. We hypothesize the two phenotypic courses of affected individuals to be dependent on two different pathogenic mechanisms: (1) a weakened inhibitory STX1A-STXBP1 interaction due to missense variants results in an STX1A-related developmental epileptic encephalopathy and (2) a hampered SNARE complex formation due to inframe deletions causes an STX1A-related intellectual disability and autism phenotype. Our description of a STX1A-related neurodevelopmental disorder with or without epilepsy thus expands the group of rare diseases called SNAREopathies.
CRIS-Team WoS Importer:2023-01-13

Heterozygous carriage of the alpha1-antitrypsin Pi∗Z variant increases the risk to develop liver cirrhosis - Strnad, Pavel; Buch, Stephan; Hamesch, Karim; Fischer, Janett; Rosendahl, Jonas; Schmelz, Renate; Brueckner, Stefan; Brosch, Mario; Heimes, Carolin V.; Woditsch, Vivien; Scholten, David; Nischalke, Hans Dieter; et al. (Gut, 2019)
Objective Homozygous alpha1-antitrypsin (AAT) deficiency increases the risk for developing cirrhosis, whereas the relevance of heterozygous carriage remains unclear. Hence, we evaluated the impact of the two most relevant AAT variants ('Pi∗Z' and 'Pi∗S'), present in up to 10% of Caucasians, on subjects with non-alcoholic fatty liver disease (NAFLD) or alcohol misuse. Design We analysed multicentric case-control cohorts consisting of 1184 people with biopsy-proven NAFLD and of 2462 people with chronic alcohol misuse, both cohorts comprising cases with cirrhosis and controls without cirrhosis. Genotyping for the Pi∗Z and Pi∗S variants was performed. Results The Pi∗Z variant presented in 13.8% of patients with cirrhotic NAFLD but only in 2.4% of counterparts without liver fibrosis (p<0.0001). Accordingly, the Pi∗Z variant increased the risk of NAFLD subjects to develop cirrhosis (adjusted OR=7.3 (95% CI 2.2 to 24.8)). Likewise, the Pi∗Z variant presented in 6.2% of alcohol misusers with cirrhosis but only in 2.2% of alcohol misusers without significant liver injury (p<0.0001). Correspondingly, alcohol misusers carrying the Pi∗Z variant were prone to develop cirrhosis (adjusted OR=5.8 (95% CI 2.9 to 11.7)). In contrast, the Pi∗S variant was not associated with NAFLD-related cirrhosis and only borderline with alcohol-related cirrhosis (adjusted OR=1.47 (95% CI 0.99 to 2.19)). Conclusion The Pi∗Z variant is the hitherto strongest single nucleotide polymorphism-based risk factor for cirrhosis in NAFLD and alcohol misuse, whereas the Pi∗S variant confers only a weak risk in alcohol misusers. As 2%-4% of Caucasians are Pi∗Z carriers, this finding should be considered in genetic counselling of affected individuals.
CRIS-Team Scopus Importer:2019-05-21
Keywords: alcoholic liver disease; alpha1-antitrypsin deficiency; fibrosis; NASH; SERPINA1

Heterozygous SOX9 mutations allowing for residual DNA-binding and transcriptional activation lead to the acampomelic variant of Campomelic Dysplasia. - Wegner, Michael; et al. (Human Mutation, 2010)
Campomelic dysplasia is a malformation syndrome with multiple symptoms including characteristic shortness and bowing of the long bones (campomelia). CD, often lethal due to airway malformations, is caused by heterozygous mutations in SOX9, an SRY-related gene regulating testis and chondrocyte development including expression of many cartilage genes such as type II collagen. Male to female sex reversal occurs in the majority of affected individuals with an XY karyotype. A mild form without campomelia exists, in which sex-reversal may be also absent. We report here two novel SOX9 missense mutations in a male (c.495C>G; p.His165Gln) and a female (c.337A>G; p.Met113Val) within the DNA-binding domain leading to non-lethal acampomelic CD. Functional analyses of mutant proteins demonstrate residual DNA-binding and transactivation of SOX9-regulated genes. Combining our data and reports from the literature we postulate a genotype-phenotype correlation: SOX9 mutations allowing for residual function lead to a mild form of CD in which campomelia and sex reversal may be absent. ©2010 Wiley-Liss, Inc.
UnivIS-Import:2015-03-09:Pub.2010.med.IB.LPCIPDBI.hetero
Keywords: Acampomelic campomelic dysplasia; Genotype-phenotype correlation; Missense mutations; SOX9 gene

Highlights from the latest articles in nanoparticles, nanomaterials and nanotoxicity testing - Lyer, Stefan; Cicha, Iwona; Friedrich, Ralf; Janko, Christina; Alexiou, Christoph (Nanomedicine, 2015)
EVALuna2:19966

Highly Conserved Interaction Profiles between Clinically Relevant Mutants of the Cytomegalovirus CDK-like Kinase pUL97 and Human Cyclins: Functional Significance of Cyclin H - Schütz, Martin; Müller, Regina; Socher, Eileen; Wangen, Christina; Full, Florian; Wyler, Emanuel; Wong, Diana D.; Scherer, Myriam; Stamminger, Thomas; Chou, Sunwen; Rawlinson, William D.; Hamilton, Stuart T.; et al. (International Journal of Molecular Sciences, 2022)
The complex host interaction network of human cytomegalovirus (HCMV) involves the regulatory protein kinase pUL97, which represents a viral cyclin-dependent kinase (CDK) ortholog. pUL97 interacts with the three human cyclin types T1, H, and B1, whereby the binding region of cyclin T1 and the pUL97 oligomerization region were both assigned to amino acids 231-280. We further addressed the question of whether HCMVs harboring mutations in ORF-UL97, i.e., short deletions or resistance-conferring point mutations, are affected in the interaction with human cyclins and viral replication. To this end, clinically relevant UL97 drug-resistance-conferring mutants were analyzed by whole-genome sequencing and used for genetic marker transfer experiments. The recombinant HCMVs indicated conservation of pUL97–cyclin interaction, since all viral UL97 point mutants continued to interact with the analyzed cyclin types and exerted wild-type-like replication fitness. In comparison, recombinant HCMVs UL97 Δ231-280 and also the smaler deletion Δ236-275, but not Δ241-270, lost interaction with cyclins T1 and H, showed impaired replication efficiency, and also exhibited reduced kinase activity. Moreover, a cellular knock-out of cyclins B1 or T1 did not alter HCMV replication phenotypes or pUL97 kinase activity, possibly indicating alternative, compensatory pUL97–cyclin interactions. In contrast, however, cyclin H knock-out, similar to virus deletion mutants in the pUL97–cyclin H binding region, exhibited strong defective phenotypes of HCMV replication, as supported by reduced pUL97 kinase activity in a cyclin H-dependent coexpression setting. Thus, cyclin H proved to be a very relevant determinant of pUL97 kinase activity and viral replication efficiency. As a conclusion, the results provide evidence for the functional importance of pUL97–cyclin interaction. High selective pressure on the formation of pUL97–cyclin complexes was identified by the use of clinically relevant mutants<br

High-resolution crystal structures of two prototypical β- And γ-herpesviral nuclear egress complexes unravel the determinants of subfamily specificity - Muller, Yves; Häge, Sigrun; Alkhashrom, Sewar; Höllriegl, Tobias; Weigert, Sebastian; Dolles, Simon; Hof, Kerstin; Walzer, Sascha; Egerer-Sieber, Claudia; Conrad, Marcus; Holst, Stephanie; Lösing, Josephine; et al. (Journal of Biological Chemistry, 2020)
Herpesviruses uniquely express two essential nuclear egress-regulating proteins forming a heterodimeric basic structure of the nuclear egress complex (core NEC). These core NECs serve as a hexameric lattice-structured platform for capsid docking and recruit viral and cellular NEC-associated factors that jointly exert nuclear lamina- and membrane-rearranging functions (multicomponent NEC). Here, we report the X-ray structures of β- and γ-herpesvirus core NECs obtained through an innovative recombinant expression strategy based on NEC-hook::NEC-groove protein fusion constructs. This approach yielded the first structure of γ-herpesviral core NEC, namely the 1.56 Å structure of Epstein-Barr virus (EBV) BFRF1-BFLF2, as well as an increased resolution 1.48 Å structure of human cytomegalovirus (HCMV) pUL50-pUL53. Detailed analysis of these structures revealed that the prominent hook segment is absolutely required for core NEC formation and contributes approximately 80% of the interaction surface of the globular domains of NEC proteins. Moreover, using HCMV::EBV hook domain swap constructs, computational prediction of the roles of individual hook residues for binding, and quantitative binding assays with synthetic peptides presenting the HCMV- and EBV-specific NEC hook sequences, we characterized the unique hook-into-groove NEC interaction at various levels. Although the overall physicochemical characteristics of the protein interfaces differ considerably in these β- and γ-herpesvirus NECs, the binding free energy contributions of residues displayed from identical positions are similar. In summary, the results of our study reveal critical details of the molecular mechanism of herpesviral NEC interactions and highlight their potential as an antiviral drug target.
CRIS-Team Scopus Importer:2020-03-17

High-resolution HPLC-ESI-MS characterization of the contact sites of the actin-thymosin ?(4) complex by chemical and enzymatic cross-linking - Knop, Jana; App, Christine; Horn, Anselm; Iavarone, Federica; Castagnola, Massimo; Hannappel, Ewald (Biochemistry, 2013)
Thymosin ?4 sequesters actin by formation of a 1:1 complex. This transient binding in the complex was stabilized by formation of covalent bonds using the cross-linking agents 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and a microbial transglutaminase. The localization of cross-linking sites was determined after separating the products using SDS-PAGE by tryptic in-gel digestion and high-resolution HPLC-ESI-MS. Three cross-linked fragments were identified after chemical cross-linking, indicating three contact sites. Because the cross-linked fragments were detected simultaneously with the corresponding non-cross-linked fragments, the three contact sites were not formed in parallel. K3 of thymosin ?4 was cross-linked to E167 of actin, K18 or K19 of thymosin ?4 to one of the first three amino acids of actin (DDE), and S43 of thymosin ?4 to H40 of actin. The imidazole ring of histidine was proven to be an acyl acceptor for carbodiimide-mediated cross-linking. Molecular modeling proved an extended conformation of thymosin ?4 along the subdomains 1 to 3 of actin. The enzymatic cross-linking using a microbial transglutaminase led to the formation of three cross-linking sites. Q41 of actin was cross-linked to K19 of thymosin ?4, and K61 of actin to Q39 of thymosin ?4. The third cross-linking site was identified between Q41 of actin and Q39 of thymosin ?4, which are simultaneously cross-linked to K16, K18, or K19 of thymosin ?4. When both cross-linking reactions are taken together, the complex formation of actin by thymosin ?4 is more likely to be flexible than rigid and is localized along the subdomains 1 to 3 of actin.
EVALuna2:4937

High-resolution mass spectrometry for thymosins detection and characterization - Cabras, Tiziana; Iavarone, Federica; Martelli, Claudia; Delfino, Daniela; Rossetti, Diana Valeria; Inserra, Ilaria; Manconi, Barbara; Desiderio, Claudia; Messana, Irene; Hannappel, Ewald; Faa, Gavino; Castagnola, Massimo (Expert Opinion on Biological Therapy, 2015)
The aim of this study was to characterize ? and ? thymosins and their proteoforms in various tissues and bodily fluids by mass spectrometry and to look at their association with a wide variety of pathologies.A top-down proteomic platform based on high-performance liquid chromatography (HPLC) coupled to high-resolution LTQ-Orbitrap mass spectrometry (MS) was applied to the characterization of naturally occurring peptides.In addition to thymosin ?4 (T?4) and ?10 (T?10), several post-translational modifications of both these peptides were identified not only in bodily fluids but also in normal and pathological tissues of different origins. The analysis of tissue specimens allowed the characterization of different C-terminal truncated forms of T?4 and T?10 together with other proteolytic fragments. The sulfoxide derivative of both T?4 and T?10 and the acetylated derivatives at lysine residues of T?4 were also characterized. Different proteoforms of prothymosin ?, parathymosin ?, thymosin ?1 and thymosin ?11 together with diverse proteolytic fragments were identified too.The clinical and prognostic significance and the origin of these proteoforms have to be deeply investigated.
EVALuna2:4973

High specificity THz metamaterial-based biosensor for label-free transcription factor detection in melanoma diagnostics - Richter, Merle; Loth, Yannik; Wigger, Anna Katharina; Nordhoff, Daniela; Rachinger, Nicole; Weisenstein, Christian; Boßerhoff, Anja Katrin; Bolívar, Peter Haring (Scientific Reports, 2023)
In this work, we present a promising diagnostic tool for melanoma diagnosis. With the proposed terahertz biosensor, it was possible to selectively and sensitively detect the early growth response protein 2, a transcription factor with an increased activity in melanoma cells, from a complex sample of cellular proteins. Fundamentally, the sensor belongs to the frequency selective surface type metamaterials and consists of a two-dimensional array of asymmetrically, doubly split ring resonator unit cells. The single elements are slits in a metallic layer and are complemented by an undercut etch. This allows a selective functionalization of the active area of the sensor and increases the sensitivity towards the target analyte. Hereby, specific detection of a defined transcription factor is feasible.
CRIS-Team Scopus Importer:2023-12-08

Histone deacetylase expressions in hepatocellular carcinoma and functional effects of histone deacetylase inhibitors on liver cancer cells in vitro - Freese, Kim; Seitz, Tatjana; Dietrich, Peter; Lee, Serene M.L.; Thasler, Wolfgang E.; Boßerhoff, Anja Katrin; Hellerbrand, Claus (Cancers, 2019)
Hepatocellular carcinoma (HCC) is a leading cause for deaths worldwide. Histone deacetylase (HDAC) inhibition (HDACi) is emerging as a promising therapeutic strategy. However, most pharmacological HDACi unselectively block different HDAC classes and their molecular mechanisms of action are only incompletely understood. The aim of this study was to systematically analyze expressions of different HDAC classes in HCC cells and tissues and to functionally analyze the effect of theHDACisuberanilohydroxamic acid (SAHA) and trichostatinA(TSA) on the tumorigenicity of HCC cells. The gene expression of all HDAC classes was significantly increased in human HCC cell lines (Hep3B, HepG2, PLC, HuH7) compared to primary human hepatocytes (PHH). The analysis of HCC patient data showed the increased expression of several HDACs in HCC tissues compared to non-tumorous liver. However, there was no unified picture of regulation in three different HCC patient datasets and we observed a strong variation in the gene expression of different HDACs in tumorous as well as non-tumorous liver. Still, there was a strong correlation in the expression of HDAC class IIa (HDAC4, 5, 7, 9) as well as HDAC2 and 8 (class I) and HDAC10 (class IIb) and HDAC11 (class IV) in HCC tissues of individual patients. This might indicate a common mechanism of the regulation of these HDACs in HCC. The Cancer Genome Atlas (TCGA) dataset analysis revealed that HDAC4, HDAC7 and HDAC9 as well as HDAC class I members HDAC1 and HDAC2 is significantly correlated with patient survival. Furthermore, we observed that SAHA and TSA reduced the proliferation, clonogenicity and migratory potential of HCC cells. SAHA but not TSA induced features of senescence in HCC cells. Additionally, HDACi enhanced the efficacy of sorafenib in killing sorafenib-susceptible cells. Moreover, HDACi reestablished sorafenib sensitivity in resistant HCC cells. In summary, HDACs are significantly but differently increased in HCC, which may be exploited to develop more targeted therapeutic approaches. HDACi affect different facets of the tumorigenicity of HCC cells and appears to be a promising therapeutic approach alone or in combination with sorafenib.
CRIS-Team Scopus Importer:2019-11-22
Keywords: Hepatocellular carcinoma; Histone deacetylase; Histone deacetylase inhibitor; Sorafenib

HIV-1 fusion is blocked through binding of GB Virus C E2D peptides to the HIV-1 gp41 disulfide loop - Eißmann, Kristin; Müller, Sebastian; Sticht, Heinrich; Jung, Susan; Zou, Peng; Jiang, Shibo; Gross, Andrea; Eichler, Jutta; Fleckenstein, Bernhard; Reil, Heide (PLoS ONE, 2013)
A strategy for antiviral drug discovery is the elucidation and imitation of viral interference mechanisms. HIV-1 patients benefit from a coinfection with GB Virus C (GBV-C), since HIV-positive individuals with long-term GBV-C viraemia show better survival rates than HIV-1 patients without persisting GBV-C. A direct influence of GBV-C on HIV-1 replication has been shown in coinfection experiments. GBV-C is a human non-pathogenic member of the flaviviridae family that can replicate in T and B cells. Therefore, GBV-C shares partly the same ecological niche with HIV-1. In earlier work we have demonstrated that recombinant glycoprotein E2 of GBV-C and peptides derived from the E2 N-terminus interfere with HIV entry. In this study we investigated the underlying mechanism. Performing a virus-cell fusion assay and temperature-arrested HIV-infection kinetics, we provide evidence that the HIV-inhibitory E2 peptides interfere with late HIV-1 entry steps after the engagement of gp120 with CD4 receptor and coreceptor. Binding and competition experiments revealed that the N-terminal E2 peptides bind to the disulfide loop region of HIV-1 transmembrane protein gp41. In conjunction with computational analyses, we identified sequence similarities between the N-termini of GBV-C E2 and the HIV-1 glycoprotein gp120. This similarity appears to enable the GBV-C E2 N-terminus to interact with the HIV-1 gp41 disulfide loop, a crucial domain involved in the gp120-gp41 interface. Furthermore, the results of the present study provide initial proof of concept that peptides targeted to the gp41 disulfide loop are able to inhibit HIV fusion and should inspire the development of this new class of HIV-1 entry inhibitors.
EVALuna2:8190

HIV-Nef and ADAM17-Containing Plasma Extracellular Vesicles Induce and Correlate with Immune Pathogenesis in Chronic HIV Infection - Lee, Jung-Hyun; Schierer, Stephan; Blume, Katja; Dindorf, Jochen; Wittki, Sebastian; Xiang, Wei; Ostalecki, Christian; Koliha, Nina; Wild, Stefan; Schuler, Gerold; Fackler, Oliver T.; Saksela, Kalle; et al. (EBioMedicine, 2016)
Antiretroviral therapy (ART) efficiently suppresses HIV replication but immune activation and low CD4 T cell counts often persist. The underlying mechanism of this ART-resistant pathogenesis is not clear. We observed that levels of plasma extracellular vesicles (pEV) are strongly elevated in HIV infection and do not decline during ART. Surprisingly, these vesicles contained the viral accessory proteins Nef and Vpu, which are assumed to be not expressed under efficient ART, as well as pro-inflammatory effectors, including activated ADAM17. HIV pEV were characterized by the presence of activated ?v?3 and absence of CD81 and Tsg101. Correlating with immune activation, peripheral monocytes ingested large amounts of pEV, giving rise to an increased population of CD1c(+) CD14(+) cells that secreted inflammatory cytokines. Importantly, the pro-inflammatory content, particularly ADAM17 activity, correlated with low T cell counts. Preliminary evidence suggested that HIV pEV derived from peripheral mononuclear cells and from an unknown myeloid cell population. In summary we propose an important role of pro-inflammatory pEV in chronic HIV infection due to ongoing viral Nef activity.
EVALuna2:4716

Homodimerization of a proximal region within the C-terminus of the orphan G-protein coupled receptor GPR179 - Bachert, Wolfrat; Klotz, Lisa; Sticht, Heinrich; Enz, Ralf (Neurochemistry International, 2021)
G-protein coupled receptors exhibit numerous biological functions. The orphan G-protein coupled receptor GPR179 is a central component of a 1 Megadalton large signalling complex in the ON-pathway of the mammalian retina that assembles multiple proteins, including the metabotropic glutamate receptor mGluR6. Dimer formation is a hallmark of G-protein coupled receptors and some use intracellular C-termini for dimerization. Here we tested the dimerization properties of the intracellular C-terminal domains of mGluR6 and GPR179. While the C-termini of GPR179 and mGluR6 did not interact, we detected a robust homodimerization of a proximal region in the GPR179 C-terminus. Mapping studies defined a linear stretch of 64 amino acids as dimerization region. Bioinformatic analysis indicated that this dimerization region might adopt an α-helical structure that is predicted to dimerize by forming a coiled-coil. Based on these data, we speculate that homodimerization of GPR179 might contribute to the formation of large signalling complexes in the mammalian retina.
CRIS-Team Scopus Importer:2021-08-13
Keywords: C-terminus; Coiled-coil; GPR179; mGluR6; Protein-protein interaction; Retina

Hop-derived Humulinones Reveal Protective Effects in in vitro Models of Hepatic Steatosis, Inflammation and Fibrosis. - Mahli, Abdo; Thasler, Wolfgang E.; Biendl, Martin; Hellerbrand, Claus (Planta Medica, 2023)
Nonalcoholic fatty liver disease (NAFLD) is emerging as leading cause of liver disease worldwide. Specific pharmacologic therapy for NAFLD is a major unmet medical need. Recently, iso-alpha acids, hop-derived bitter compounds in beer, have been shown to beneficially affect NAFLD pathology. Humulinones are further hop derived bitter acids particularly found in modern styles of beer. So far, biological effects of humulinones have been unknown. Here, we investigated the effect of humulinones in in vitro models for hepatic steatosis, inflammation and fibrosis. Humulinones dose-dependently inhibited fatty acid induced lipid accumulation in primary human hepatocytes. Humulinones reduced the expression of fatty acid uptake transporter CD36 and key enzymes of (de novo) lipid synthesis. Conversely, humulinones increased the expression of FABP1, CPT1 and ACOX1, indicative for increased lipid combustion. Furthermore, humulinones ameliorated steatosis induced pro-inflammatory gene expression. Furthermore, humulinones significantly reduced the expression of pro-inflammatory and pro-fibrogenic factors in control as well as lipopolysaccharide treated activated hepatic stellate cells, which play a key role in hepatic fibrosis. In conclusion, humulinones beneficially affect different pathophysiological steps of NAFLD. Our data suggest humulinones as promising therapeutic agents for the prevention and treatment of NAFLD.
EVALuna2:536972

Human cytomegalovirus immediate-early gene 2 expression leads to JCV replication in nonpermissive cells via transcriptional activation of JCV T antigen - Wegner, Michael; et al. (Virology, 2000)
Human papovavirus JCV is the causative agent of the demyelinating brain disease progressive multifocal leukoencephalopathy (PML) that typically develops as a complication of impaired immunocompetence. JCV displays a strong tropism for glial cells which is correlated by glial-specific transcriptional regulation of viral gene expression. In a previous report HCMV was shown to overcome the restricted cell specificity of JCV by inducing DNA replication of a PML-derived JCV strain in human fibroblasts which are nonpermissive for the replication of JCV alone. Here we show that productive JCV replication is induced by HCMV in human glioblastoma cells. Both in fibroblasts and in glioblastoma cells, the HCMV immediate-early transactivator 2 (IE2) is sufficient to mediate JCV replication. Furthermore, IE2 induces DNA replication of several structurally different brain- or kidney-derived JCV variants. IE2-induced JCV DNA replication is accompanied by the induction of JCV T antigen expression due to stimulation of the JCV early promoter. Our results indicate that stimulation of JCV early gene expression by HCMV-IE2 is sufficient to overcome the restricted cell specificity of JCV. (C) 2000 Academic Press.
UnivIS-Import:2015-03-05:Pub.2000.med.IB.LPCIPDBI.humanc

Human Cytomegalovirus Nuclear Capsids Associate with the Core Nuclear Egress Complex and the Viral Protein Kinase pUL97 - Milbradt, Jens; Sonntag, Eric; Wagner, Sabrina; Strojan, Hanife; Wangen, Christina; Rovis, Tihana Lenac; Lisnic, Berislav; Jonjic, Stipan; Sticht, Heinrich; Britt, William J.; Schlötzer-Schrehardt, Ursula; Marschall, Manfred (Viruses, 2018)
The nuclear phase of herpesvirus replication is regulated through the formation of regulatory multi-component protein complexes. Viral genomic replication is followed by nuclear capsid assembly, DNA encapsidation and nuclear egress. The latter has been studied intensely pointing to the formation of a viral core nuclear egress complex (NEC) that recruits a multimeric assembly of viral and cellular factors for the reorganization of the nuclear envelope. To date, the mechanism of the association of human cytomegalovirus (HCMV) capsids with the NEC, which in turn initiates the specific steps of nuclear capsid budding, remains undefined. Here, we provide electron microscopy-based data demonstrating the association of both nuclear capsids and NEC proteins at nuclear lamina budding sites. Specifically, immunogold labelling of the core NEC constituent pUL53 and NEC-associated viral kinase pUL97 suggested an intranuclear NEC-capsid interaction. Staining patterns with phospho-specific lamin A/C antibodies are compatible with earlier postulates of targeted capsid egress at lamina-depleted areas. Important data were provided by co-immunoprecipitation and in vitro kinase analyses using lysates from HCMV-infected cells, nuclear fractions, or infectious virions. Data strongly suggest that nuclear capsids interact with pUL53 and pUL97. Combined, the findings support a refined concept of HCMV nuclear trafficking and NEC-capsid interaction.
EVALuna2:33716

Human Induced Pluripotent Stem Cell-Derived Pericytes as Scalable and Editable Source to Study Direct Lineage Reprogramming Into Induced Neurons - Menon, Radhika; Petrucci, Linda; Lohrer, Benjamin; Zhang, Jingzhong; Schulze, Markus; Schichor, Christian; Winner, Beate; Winkler, Jürgen; Riemenschneider, Markus J.; Kühn, Ralf; Falk, Sven; Karow, Marisa (Cellular Reprogramming, 2023)
Studying human somatic cell-to-neuron conversion using primary brain-derived cells as starting cell source is hampered by limitations and variations in human biopsy material. Thus, delineating the molecular variables that allow changing the identity of somatic cells, permit adoption of neuronal phenotypes, and foster maturation of induced neurons (iNs) is challenging. Based on our previous results that pericytes derived from the adult human cerebral cortex can be directly converted into iNs (Karow et al., 2018; Karow et al., 2012), we here introduce human induced pluripotent stem cell (hiPSC)-derived pericytes (hiPSC-pericytes) as a versatile and more uniform tool to study the pericyte-to-neuron conversion process. This strategy enables us to derive scalable cell numbers and allows for engineering of the starting cell population such as introducing reporter tools before differentiation into hiPSC-pericytes and subsequent iN conversion. Harvesting the potential of this approach, we established hiPSC-derived human-human neuronal cocultures that not only allow for independent manipulation of each coculture partner but also resulted in morphologically more mature iNs. In summary, we exploit hiPSC-based methods to facilitate the analysis of human somatic cell-to-neuron conversion.
CRIS-Team Scopus Importer:2023-11-03
Keywords: direct lineage reprogramming; induced neurons; organoids; pericytes

Hurdling senescence: hur breaks braf-induced senescence in melanocytes and supports melanoma growth - Liebig, Janika; Kuphal, Silke; Boßerhoff, Anja Katrin (Cancers, 2020)
In addition to genetic changes, post-transcriptional events strongly contribute to the progression of malignant tumors. The RNA-binding protein HuR (ELAVL1) is able to bind and stabilize a large group of target mRNAs, which contain AU-rich elements (ARE) in their 3′- untranslated region. We found HuR to be upregulated in malignant melanoma in vitro and in vivo, significantly correlating with progression in vivo. Additionally, we could show that miR-194-5p can regulate HuR expression level. HuR knockdown in melanoma cells led to the suppression of proliferation and the induction of cellular senescence. Interestingly, HuR overexpression was sufficient to inhibit senescence in BRAFV600E -expressing melanocytes and to force their growth. Here, MITF (Microphthalmia-associated transcription factor), a key player in suppressing senescence and an ARE containing transcript, is positively regulated by HuR. Our results show for the first time that the overexpression of HuR is an important part of the regulatory pathway in the development of malignant melanoma and functions as a switch to overcome oncogene-induced senescence and to support melanoma formation. These newly defined alterations may provide possibilities for innovative therapeutic approaches.
CRIS-Team Scopus Importer:2020-06-02
Keywords: HuR; Malignant melanoma; Microphthalmia-associated transcription factor; MITF; Oncogene induced senescence

Hybrid compounds: from simple combinations to nanomachines - Mueller-Schiffmann, Andreas; Sticht, Heinrich; Korth, Carsten (Biodrugs, 2012)
The combination of two different and independently acting compounds into one covalently linked hybrid compound can convey synergy from the effects of both independently acting moieties to the new composite compound, leading to a pharmacological potency greater than the sum of each individual moiety's potencies. Here, we review a variety of such hybrid compounds, which can consist of various functional parts, molecular recognition or subcellular targeting moieties, or combinations thereof, acting either simultaneously or sequentially. Such moieties within a hybrid compound can consist of a variety of substance classes, including small organic molecules, polypeptides or nucleic acids identified either via rational molecular design or selection from libraries. Precedent for hybrid compounds comes from naturally occurring proteins and small molecules, such as botulinum toxin and bleomycin, which are secreted by micro-organisms. We review the high degree of suitability of hybrid compounds for the treatment of multifactorial diseases by simultaneously hitting several targets along an identified disease pathway. Examples are hybrid compounds against Alzheimer's disease, against the cancer-relevant phosphoinisitide-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) and epidermal growth factor signaling cascade, or in antimalarial therapy via simultaneous hitting of different mechanisms of hemozoin formation. Molecular recognition by peptides or aptamers (recognition-specific RNA or peptide sequences) can be combined with the transport of small molecule ?-sheet breakers or toxins, or targeting to ubiquitin-dependent proteolysis. The vision of molecular nanomachines is currently realized in sequentially acting modular nanotransporters, consisting of four modules including a target, a membrane and nuclear translocation sequence, as well as a drug attachment domain. Through the rational combination of existing drugs and the synergy of their effects, a rapid amplification of their potency may be achieved, greatly accelerating drug development. A further enhancement of simultaneous multitarget action is enabled through the design of multifunctional hybrid drugs with sequential effects that make these hybrid molecules resemble intelligent nanomachines.
EVALuna2:26273

Hypomorphic Pathogenic Variants in TAF13 Are Associated with Autosomal-Recessive Intellectual Disability and Microcephaly - Tawamie, Hasan; Martianov, Igor; Wohlfahrt, Natalie; Buchert, Rebecca; Mengus, Gabrielle; Uebe, Steffen; Janiri, Luigi; Hirsch, Franz Wolfgang; Schumacher, Johannes; Ferrazzi, Fulvia; Sticht, Heinrich; Reis, André; et al. (American Journal of Human Genetics, 2017)
In two independent consanguineous families each with two children affected by mild intellectual disability and microcephaly, we identified two homozygous missense variants (c.119T>A [p.Met40Lys] and c.92T>A [p.Leu31His]) in TATA-box-binding-protein-associated factor 13 (TAF13). Molecular modeling suggested a pathogenic effect of both variants through disruption of the interaction between TAF13 and TAF11. These two proteins form a histone-like heterodimer that is essential for their recruitment into the general RNA polymerase II transcription factor IID (TFIID) complex. Co-immunoprecipitation in HeLa cells transfected with plasmids encoding TAF11 and TAF13 revealed that both variants indeed impaired formation of the TAF13-TAF11 heterodimer, thus confirming the protein modeling analysis. To further understand the functional role of TAF13, we performed RNA sequencing of neuroblastoma cell lines upon TAF13 knockdown. The transcriptional profile showed significant deregulation of gene expression patterns with an emphasis on genes related to neuronal and skeletal functions and those containing E-box motives in their promoters. Here, we expand the spectrum of TAF-associated phenotypes and highlight the importance of TAF13 in neuronal functions.
EVALuna2:9362

Hypomorphic Sox10 alleles reveal novel protein functions and unravel developmental differences in glial lineages. - Wegner, Michael; Bösl, Rebecca; et al. (Development, 2007)
The transcription factor Sox10 regulates early neural crest development, specification of neural crest-derived lineages and terminal differentiation of oligodendrocytes in the central nervous system. Here, we generated two novel hypomorphic Sox10 alleles in the mouse. Mutant mice either expressed a Sox10 protein with a triple alanine substitution in the dimerization domain, or a Sox1O protein with a deletion in the central portion that we define as a cell-specific transactivation domain. Phenotypic analysis revealed important roles for a functional dimerization domain and the newly defined novel transactivation domain in melanocyte and enteric nervous system development, whereas early neural crest development and oligodendrocyte differentiation were surprisingly little disturbed in both mutants. Unique requirements were additionally detected for the novel transactivation domain in satellite glia differentiation and during Schwann cell myelination, whereas DNA-dependent dimerization was needed for immature Schwann cells to enter the promyelinating stage. These two hypomorphic alleles thus uncover novel functions of Sox10 in satellite glia and Schwann cells during late developmental stages and reveal important developmental differences between these two types of peripheral glia and oligodendrocytes regarding their reliance on Sox10.
UnivIS-Import:2015-03-09:Pub.2007.med.IB.LPCIPDBI.hypomo
Keywords: Glia; High mobility group; Neural crest; Oligodendrocyte; Satellite glia; Schwann cell; Sry

Hypoxia-Inducible Factor 1 Is an Inductor of Transcription Factor Activating Protein 2 Epsilon Expression during Chondrogenic Differentiation - Niebler, Stephan; Angele, Peter; Kujat, Richard; Boßerhoff, Anja Katrin (BioMed Research International, 2015)
The transcription factor AP-2? (activating enhancer-binding protein epsilon) is expressed in cartilage of humans and mice. However, knowledge about regulatory mechanisms influencing AP-2? expression is limited. Using quantitative real time PCR, we detected a significant increase in AP-2? mRNA expression comparing initial and late stages of chondrogenic differentiation processes in vitro and in vivo. Interestingly, in these samples the expression pattern of the prominent hypoxia marker gene angiopoietin-like 4 (Angptl4) strongly correlated with that of AP-2? suggesting that hypoxia might represent an external regulator of AP-2? expression in mammals. In order to show this, experiments directly targeting the activity of hypoxia-inducible factor-1 (HIF1), the complex mediating responses to oxygen deprivation, were performed. While the HIF1-activating compounds 2,2'-dipyridyl and desferrioxamine resulted in significantly enhanced mRNA concentration of AP-2?, siRNA against HIF1? led to a significantly reduced expression rate of AP-2?. Additionally, we detected a significant upregulation of the AP-2? mRNA level after oxygen deprivation. In sum, these different experimental approaches revealed a novel role for the HIF1 complex in the regulation of the AP-2? gene in cartilaginous cells and underlined the important role of hypoxia as an important external regulatory stimulus during chondrogenic differentiation modulating the expression of downstream transcription factors.
EVALuna2:4720

Identification and characterisation of Simiate, a novel protein linked to the fragile X syndrome - Derlig, Kristin; Gießl, Andreas; Brandstätter, Johann Helmut; Enz, Ralf; Dahlhaus, Regina (PLoS ONE, 2013)
A strict regulation of protein expression during developmental stages and in response to environmental signals is essential to every cell and organism. Recent research has shown that the mammalian brain is particularly sensitive to alterations in expression patterns of specific proteins and cognitive deficits as well as autistic behaviours have been linked to dysregulated protein expression. An intellectual disability characterised by changes in the expression of a variety of proteins is the fragile X syndrome. Due to the loss of a single mRNA binding protein, the Fragile X Mental Retardation Protein FMRP, vast misregulation of the mRNA metabolism is taking place in the disease. Here, we present the identification and characterisation of a novel protein named Simiate, whose mRNA contains several FMRP recognition motifs and associates with FMRP upon co-precipitation. Sequence analysis revealed that the protein evolved app. 1.7 billion years ago when eukaryotes developed. Applying antibodies generated against Simiate, the protein is detected in a variety of tissues, including the mammalian brain. On the subcellular level, Simiate localises to somata and nuclear speckles. We show that Simiate and nuclear speckles experience specific alterations in FMR1(-/-) mice. An antibody-based block of endogenous Simiate revealed that the protein is essential for cell survival. These findings suggest not only an important role for Simiate in gene transcription and/or RNA splicing, but also provide evidence for a function of nuclear speckles in the fragile X syndrome. Indeed, transcription and splicing are two fundamental mechanisms to control protein expression, that underlie not only synaptic plasticity and memory formation, but are also affected in several diseases associated with mental disabilities.
EVALuna2:4700

Identification and Site Specific Relative Quantification of beta-Lactoglobulin Modifications in Heated Milk and Dairy Products - Meltretter, Jasmin; Becker, Cord-Michael; Pischetsrieder, Monika (Journal of Agricultural and Food Chemistry, 2008)
During milk processing, proteins can be severely modified by oxidation, condensation, and Maillard reaction, leading to changes in their nutritional and technological properties. In this study, major modifications of β-lactoglobulin, formed during the heating and processing of milk, were screened by mass spectrometry. For this purpose, β-lactoglobulin was isolated from the milk samples by gel electrophoresis and analyzed by matrix-assisted laser desorption/ionization mass spectrometry after in-gel digestion with endoproteinase AspN. In heated milk, lactulosyllysine was detected at lysine 47 and 138 or 141 as well as methionine sulfoxide at methionine 7, 24, and 145. All these modifications increased gradually when raw milk was heated for 20, 40, and 60 min at 120°C. The major modifications were also relatively quantified in dairy products, such as raw, high-temperature, ultra-high-temperature, sterilized, and condensed milk as well as infant formulas. The highest contents of lactulosyllysine at Lys47 were detected in powdered infant formulas, whereas lactulosyllysine at Lys138/141 was predominant in condensed milk samples. Methionine sulfoxide at Met7 and Met24 showed a trend toward higher modification rates in more severely processed products. © 2008 American Chemical Society.
UnivIS-Import:2015-04-14:Pub.2008.nat.dchph.llmch.identi
Keywords: β-Lactoglobulin; Glycation; Maillard reaction; Matrix-assisted laser desorption/ionization mass spectrometry; Milk; Oxidation

Identification of 70 amino acids important for GABAC receptor  subunit assembly. - Enz, Ralf; Cutting, (Brain Research, 1999)
UnivIS-Import:2017-12-18:Pub.1999.med.IB.profes_1.identi

Identification of a neutralizing epitope within antigenic domain 5 of glycoprotein B of human cytomegalovirus - Wiegers, Anna-Katharina; Sticht, Heinrich; Winkler, Thomas; Britt, William J.; Mach, Michael (Journal of Virology, 2015)
Human cytomegalovirus (HCMV) is an important, ubiquitous pathogen that causes severe clinical disease in immunocompromised individuals, such as organ transplant recipients and infants infected in utero. The envelope glycoprotein B (gB) of HCMV is a major antigen for the induction of virus-neutralizing antibodies. We have begun to define target structures within gB that are recognized by virus-neutralizing antibodies. Antigenic domain 5 (AD-5) of gB has been identified as an important target for neutralizing antibodies in studies using human monoclonal antibodies (MAbs). Anti-AD-5 MAbs share a target site on gB, despite originating from different, healthy, HCMV-infected donors. Mutational analysis of AD-5 identified tyrosine 280 in combination with other surface-exposed residues (the YNND epitope) as critical for antibody binding. The YNND epitope is strictly conserved among different HCMV strains. Recombinant viruses carrying YNND mutations in AD-5 were resistant to virus-neutralizing MAbs. Competition enzyme-linked immunosorbent assays (ELISAs) with human HCMV-convalescent-phase sera from unselected donors confirmed the conserved antibody response for the YNND epitope in HCMV-infected individuals and, because a significant fraction of the gB AD-5 response was directed against the YNND epitope, further argued that this epitope is a major target of anti-AD-5 antibody responses. In addition, affinity-purified polyclonal anti-AD-5 antibodies prepared from individual sera showed reactivity to AD-5 and neutralization activity toward gB mutant viruses that were similar to those of AD-5-specific MAbs. Taken together, our data indicate that the YNND epitope represents an important target for anti-gB antibody responses as well as for anti-AD-5 virus-neutralizing antibodies.HCMV is a major global health concern, and a vaccine to prevent HCMV disease is a widely recognized medical need. Glycoprotein B of HCMV is an important target for neutralizing antibodies and hence an interesting molecule for intervention strategies, e.g., vaccination. Mapping the target structures of neutralizing antibodies induced by naturally occurring HCMV infection can aid in defining the properties required for a protective capacity of vaccine antigens. The data presented here extend our knowledge of neutralizing epitopes within gB to include AD-5. Collectively, our data will contribute to optimal vaccine design and development of antibody-based therapies.
EVALuna2:8287

Identification of a Ninein (NIN) mutation in a family with spondyloepimetaphyseal dysplasia with joint laxity (leptodactylic type)-like phenotype - Grosch, Melanie; Gruener, Barbara; Spranger, Stephanie; Stuetz, Adrian M.; Rausch, Tobias; Korbel, Jan O.; Seelow, Dominik; Nuernberg, Peter; Sticht, Heinrich; Lausch, Ekkehart; Zabel, Bernhard; Winterpacht, Andreas; et al. (Matrix Biology, 2013)
Spondyloepimetaphyseal dysplasia with joint laxity-leptodactylic type (SEMDJL2) is an autosomal dominant skeletal dysplasia which is characterized by midface hypoplasia, short stature, joint laxity with dislocations, genua valga, progressive scoliosis, and slender fingers. Recently, heterozygous missense mutations in KIF22, a gene which encodes a member of the kinesin-like protein family, have been identified in sporadic as well as familial cases of SEMDJL2. In the present study homozygosity mapping and whole-exome sequencing were combined to analyze a consanguineous family with a phenotype resembling SEMDJL2. We identified homozygous missense mutations in the two nearby genes NIN (Ninein) and POLE2 (DNA polymerase epsilon subunit B) which segregate with the disease in the family and were not present in 500 healthy control individuals and in the 1094 control individuals contained within the 1000-genomes database. We present several lines of evidence that mutant Ninein is most likely causative for the SEMDJL2-like phenotype. The centrosomal protein NIN shows a functional relationship with KIF22 and other proteins associated with chromosome congression/movement, centrosomal function, and ciliogenesis, which have been associated with skeletal dysplasias. Moreover, compound heterozygous missense mutations at more N-terminal positions of Ninein have very recently been identified in a family with microcephalic primordial dwarfism. Together with the present report this strongly supports a fundamental role of Ninein in skeletal development.
EVALuna2:9192

Identification of a novel loss-of-function calcium channel gene mutation in short QT syndrome (SQTS6) - Templin, Christian; Ghadri, Jelena-Rima; Rougier, Jean-Sebastien; Baumer, Alessandra; Kaplan, Vladimir; Albesa, Maxime; Sticht, Heinrich; Rauch, Anita; Puleo, Colleen; Hu, Dan; Barajas-Martinez, Hector; Antzelevitch, Charles; et al. (European Heart Journal, 2011)
Short QT syndrome (SQTS) is a genetically determined ion-channel disorder, which may cause malignant tachyarrhythmias and sudden cardiac death. Thus far, mutations in five different genes encoding potassium and calcium channel subunits have been reported. We present, for the first time, a novel loss-of-function mutation coding for an L-type calcium channel subunit.The electrocardiogram of the affected member of a single family revealed a QT interval of 317 ms (QTc 329 ms) with tall, narrow, and symmetrical T-waves. Invasive electrophysiological testing showed short ventricular refractory periods and increased vulnerability to induce ventricular fibrillation. DNA screening of the patient identified no mutation in previously known SQTS genes; however, a new variant at a heterozygous state was identified in the CACNA2D1 gene (nucleotide c.2264G > C; amino acid p.Ser755Thr), coding for the Ca(v)?(2)?-1 subunit of the L-type calcium channel. The pathogenic role of the p.Ser755Thr variant of the CACNA2D1 gene was analysed by using co-expression of the two other L-type calcium channel subunits, Ca(v)1.2?1 and Ca(v)?(2b), in HEK-293 cells. Barium currents (I(Ba)) were recorded in these cells under voltage-clamp conditions using the whole-cell configuration. Co-expression of the p.Ser755Thr Ca(v)?(2)?-1 subunit strongly reduced the I(Ba) by more than 70% when compared with the co-expression of the wild-type (WT) variant. Protein expression of the three subunits was verified by performing western blots of total lysates and cell membrane fractions of HEK-293 cells. The p.Ser755Thr variant of the Ca(v)?(2)?-1 subunit was expressed at a similar level compared with the WT subunit in both fractions. Since the mutant Ca(v)?(2)?-1 subunit did not modify the expression of the pore-forming subunit of the L-type calcium channel, Ca(v)1.2?1, it suggests that single channel biophysical properties of the L-type channel are altered by this variant.In the present study, we report the first pathogenic mutation in the CACNA2D1 gene in humans, which causes a new variant of SQTS. It remains to be determined whether mutations in this gene lead to other manifestations of the J-wave syndrome.
EVALuna2:26263

Identification of developmentally regulated expression of MuSK in astrocytes of the rodent retina. - Cheusova, Tatiana; Khan, Muhammad Amir; Enz, Ralf; Hashemolhosseini, Said (Journal of Neurochemistry, 2006)
One of the master regulators of postsynaptic neuromuscular synaptogenesis is the muscle-specific receptor tyrosine kinase (MuSK). In mammals prominent MuSK expression is believed to be restricted to skeletal muscle. Upon activation by nerve-derived agrin MuSK-dependent signalling participates in both the induction of genes encoding postsynaptic components and aggregation of nicotinic acetylcholine receptors (AChR) in the subsynaptic muscle membrane. Strikingly, expression of certain isoforms of nerve-derived agrin can also be detected in the CNS. In this study, we examined the expression of MuSK in the brain and eye of rodents. In the retina MuSK was expressed in astrocytes between postnatal days 7 and 14, i.e. at the time when the eyes open. We found that agrin was localized adjacent to MuSK-expressing astrocytes which in turn were detected close to the inner limiting membrane of the rodent retina. In summary, the presence of MuSK on retinal astrocytes suggests a novel role of MuSK signalling pathways in the CNS. © 2006 The Authors.
UnivIS-Import:2015-04-14:Pub.2006.med.IB.LPCIPDBI.identi
Keywords: Agrin; Astrocytes; Eye; Muscle-specific receptor tyrosine kinase; Neuromuscular junction; Retina

Identification of eugenol as the major determinant of GABA(A)-receptor activation by aqueous Syzygium aromaticum L. (clove buds) extract - Sahin, Sümeyye; Eulenburg, Volker; Heinlein, Anja; Villmann, Carmen; Pischetsrieder, Monika (Journal of Functional Foods, 2017)
The spice Syzygium aromaticum L. (clove buds) exerts topical anesthetic and analgesic effects. Since GABA(A) receptors are an emerging drug target for pain treatment, the effects of aqueous clove extracts on the human alpha 1 beta 2-GABA(A) receptor were tested by two-electrode voltage clamp technique applying a three-step test system. The extract significantly and specifically potentiated the GABA-induced currents by an allosteric mechanism in concentration-dependent manner (0.5-5 mu g/mL up to 426 +/- 23%) HPLC-based activity-guided fractionation revealed eugenol as main determinant of this GABAergic activity. Acetyleugenol, an important component of clove bud oil, showed even higher activity than eugenol (1 mu g/mL; 308 +/- 26% versus 234 +/- 29%), but was detected in the aqueous extract only in trace amounts. Thus, the analgesic effects of clove might be partially mediated by positive modulation of the GABAA receptor and eugenol is a major contributor to this activity. (C) 2017 Elsevier Ltd. All rights reserved.
Keywords: Acetyleugenol; Analgesic activity; Clove buds; Eugenol; GABA(A) receptor; Two-electrode voltage clamp technique

Identification of interaction partners of ?-thymosins: application of thymosin ?4 labeled by transglutaminase - App, Christine; Knop, Jana; Mannherz, Hans Georg; Hannappel, Ewald (Annals of the New York Academy of Sciences, 2012)
In this review, we identify potential interaction partners of the ?-thymosin family. The proteins of this family are highly conserved peptides in mammals and yet only one intracellular (G-actin) and one cell-surface protein (? subunit of F(1) -F(0) ATP synthase) were identified as interaction partners of thymosin ?4. Cross-linking experiments may be a possible approach to discover additional proteins that interact with the ?-thymosin family. It has previously been shown that thymosin ?4 can be labeled at its glutaminyl residues with various cadaverines using tissue transglutaminase. Here, we illuminate recent results and give an outlook on upcoming work in the field.
EVALuna2:4932

Identification of novel candidate genes for idiopathic short stature using whole exome sequencing - Thiel, Christian; Hauer, Nadine; Vogl, C.; Ahmadian, R.; Dhandapany, P. S.; Popp, Bernt; Buettner, C.; Ube, S.; Sticht, Heinrich; Ferrazzi, Fulvia; Ekici, Arif Bülent; De Luca, A.; et al. (EUROPEAN JOURNAL OF HUMAN GENETICS, 2019)
CRIS-Team WoS Importer:2019-10-25

Identification of novel targets of miR-622 in hepatocellular carcinoma reveals common regulation of cooperating genes and outlines the oncogenic role of zinc finger CCHC-type containing 11 - Gaza, Anne; Fritz, Valerie; Malek, Lara; Wormser, Laura; Treiber, Nora; Danner, Johannes; Kremer, Andreas E.; Thasler, Wolfgang E.; Siebler, Jürgen; Meister, Gunter; Neurath, Markus F.; Hellerbrand, Claus; et al. (Neoplasia, 2021)
The poor prognosis of advanced hepatocellular carcinoma (HCC) is driven by diverse features including dysregulated microRNAs inducing drug resistance and stemness. Lin-28 homolog A (LIN28A) and its partner zinc finger CCHC-type containing 11 (ZCCHC11) cooperate in binding, oligouridylation and subsequent degradation of tumorsuppressive let-7 precursor microRNAs. Functionally, activation of LIN28A was recently shown to promote stemness and chemoresistance in HCC. However, the expression and regulation of LIN28A in HCC had been unclear. Moreover, the expression, regulation and function of ZCCHC11 in liver cancer remained elusive. In contrast to "one-microRNA-one-target" interactions, we identified common binding sites for miR-622 in both LIN28A and ZCCHC11, suggesting miR-622 to function as a superior pathway regulator. Applying comprehensive microRNA database screening, human hepatocytes and HCC cell lines, patient-derived tissue samples as well as "The Cancer Genome Atlas" (TCGA) patient cohorts, we demonstrated that loss of tumorsuppressive miR-622 mediates derepression and overexpression of LIN28A in HCC. Moreover, the cooperator of LIN28A, ZCCHC11, was newly identified as a prognostic and therapeutic target of miR-622 in liver cancer. Together, identification of novel miR-622 target genes revealed common regulation of cooperating genes and outlines the previously unknown oncogenic role of ZCCHC11 in liver cancer.
CRIS-Team Scopus Importer:2021-05-07
Keywords: drug resistance; HCC; Hepatocellular carcinoma; microRNA; ZCCHC11

Identification of oral squamous cell carcinoma markers MUC2 and SPRR1B downstream of TANGO - Sasahira, Tomonori; Kurihara-Shimomura, Miyako; Shimomura, Hiroyuki; Boßerhoff, Anja Katrin; Kirita, Tadaaki (Journal of Cancer Research and Clinical Oncology, 2021)
Purpose: Transport and Golgi organization protein 1 (TANGO) promotes angiogenesis and lymphangiogenesis in oral squamous cell carcinoma (OSCC). To elucidate the underlying mechanisms, this study aims to identify and characterize elements downstream of TANGO that mediate its involvement in OSCC. Methods: In this study, microarray analysis compared gene expression between control and TANGO-repressed HSC3 cells. Protein expression in 213 OSCC tissue samples was analyzed immunohistochemically. Results: TANGO repression decreased or increased expression of Mucin 20 (MUC20) and small proline-rich protein 1B (SPRR1B), respectively. MUC20 increased the growth and invasiveness of OSCC cells via altered matrix metalloproteinase (MMP)-2 and E-cadherin expression and c-met phosphorylation. MUC20 induced angiogenesis and lymphangiogenesis by activating vascular endothelial growth factors A and C. In well-differentiated OSCC, SPRR1B expression was high (P = 0.0091) and correlated with keratinization markers and promoted proliferation by inducing mitogen-activated protein kinase p38 phosphorylation. MUC20 expression correlated significantly with clinical stage (P = 0.0024), lymph node metastasis (P = 0.0036), and number of blood and lymph vessels (P < 0.0001). MUC20-expressing cases had a significantly worse prognosis than non-expressing cases (P < 0.0001). Conclusion: MUC20 and SPRR1B located downstream of TANGO may be useful molecular markers for OSCC.
CRIS-Team Scopus Importer:2021-03-12
Keywords: MUC20; Oral cancer; SPRR1B; TANGO

Identification of PDGF-BB binding to thymosin ?4 by chemical cross-linking - Knop, Jana; App, Christine; Huff, Thomas; Iavarone, Federica; Castagnola, Massimo; Hannappel, Ewald (Expert Opinion on Biological Therapy, 2015)
The purpose of our work was to identify unknown interaction partners of thymosin ?4 (T?4). It was suggested that T?4 could be an antifibrotic drug for treatment of liver fibrogenesis, because T?4 prevents the platelet-derived growth factor-BB (PDGF-BB)-induced activation of hepatic stellate cells (HSCs). Very little information is available how T?4 counteracts the PDGF-BB-induced activation of HSCs. We propose the hypothesis that T?4 could bind directly to PDGF-BB and thereby reduce the concentration of free PDGF-BB available for binding to the PDGF-? receptor.To prove our suggestion of a direct interaction between T?4 and PDGF-BB, we carried out chemical as well as photochemical cross-linking experiments between the two pure proteins in vitro.We identified an interaction between T?4 and PDGF-BB by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) cross-linking as well as through biotin label transfer using a bifunctional photoactivatable derivative of T?4. In an in vitro system, PDGF-BB was identified as the first extracellular partner interacting with T?4. This interaction could influence PDGF-BB binding to its receptor and abolish PDGF-BB-related effects.Direct interaction of T?4 with extracellular factors should be considered as a potential mechanism to explain the pleiotropic effects of ?-thymosins.
EVALuna2:4957

Identification of Sox8 as a modifier gene in a mouse model of Hirschsprung disease reveals underlying molecular defect. - Wegner, Michael; Stolt, Claus; et al. (Developmental Biology, 2005)
Mice carrying heterozygous mutations in the Sox10 gene display aganglionosis of the colon and represent a model for human Hirschsprung disease. Here, we show that the closely related Sox8 functions as a modifier gene for Sox10-dependent enteric nervous system defects as it increases both penetrance and severity of the defect in Sox10 heterozygous mice despite having no detectable influence on enteric nervous system development on its own. Sox8 exhibits an expression pattern very similar to Sox10 with occurrence in vagal and enteric neural crest cells and later confinement to enteric glia. Loss of Sox8 alleles in Sox10 heterozygous mice impaired colonization of the gut by enteric neural crest cells already at early times. Whereas proliferation, apoptosis, and neuronal differentiation were normal for enteric neural crest cells in the gut of mutant mice, apoptosis was dramatically increased in vagal neural crest cells outside the gut. The defects in enteric nervous system development of mice with Sox10 and Sox8 mutations are therefore likely caused by a reduction of the pool of undifferentiated vagal neural crest cells. Our study suggests that Sox8 and Sox10 are jointly required for the maintenance of these vagal neural crest stem cells. © 2004 Elsevier Inc. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2005.med.IB.LPCIPDBI.identi
Keywords: Enteric nervous system; High-mobility-group; Hirschsprung disease; Megacolon; Sox10; Sry

Identification of the structural features that mediate binding specificity in the recognition of STAT proteins by dual-specificity phosphatases - Jardin, Christophe; Sticht, Heinrich (Journal of Biomolecular Structure & Dynamics, 2012)
Inactivation of signal transducers and activators of transcription (STAT) proteins is regulated by dual-specificity phosphatases (DSPs) with high substrate specificity. Although experiments have provided useful information about the phosphatase activity and the specificity for STATs, there is up-to-date no data at a molecular level to explain the specific recognition of STAT substrates by this subfamily of phosphatases. Here, a combined approach of molecular modeling, docking and molecular dynamics simulations was used to address the binding between DSPs and their STAT substrates. We identified a binding interface at the protein tyrosine phosphatase (PTP) domain of the DSP VHR that interacts with the SH2-domain of STAT5. This finding is consistent with previous mutational data and supports a "two-step" mechanism for the dephosphorylation event. Application of the same approach suggests the presence of a similar interface between the viral DSP VH1 and STAT1. Furthermore, the interaction network at this interface provides an explanation for the specificity of the DSP-STAT recognition.
EVALuna2:26258

Idiopathic weight reduction in mice deficient in the high-mobility-group transcription factor Sox8 - Sock, Elisabeth; Wegner, Michael; et al. (Molecular and Cellular Biology, 2001)
Sox8, Sox9, and Sox10 constitute subgroup E within the Sox family of transcription factors. Many Sox proteins are essential regulators of development. Sox9, for instance, is required for chondrogenesis and male sex determination; Sox10 plays key roles in neural crest development and peripheral gliogenesis. The function of Sox8 has not been studied so far. Here, we generated mice deficient in this third member of subgroup E. In analogy to the case for the related Sox9 and Sox10, we expected severe developmental defects in these mice. Despite strong expression of Sox8 in many tissues, including neural crest, nervous system, muscle, cartilage, adrenal gland, kidney, and testis, homozygous mice developed normally in utero, were born at Mendelian frequencies, and were viable. A substantial reduction in weight was observed in these mice; however, this reduction was not attributable to significant structural deficits in any of the Sox8-expressing tissues. Because of frequent coexpression with either Sox9 or Sox10, the mild phenotype of Sox8-deficient mice might at least in part be due to functional redundancy between group E Sox proteins.
UnivIS-Import:2015-03-09:Pub.2001.med.IB.LPCIPDBI.idiopa

IFN-γ-response mediator GBP-1 represses human cell proliferation by inhibiting the Hippo signaling transcription factor TEAD - Unterer, Bea; Wiesmann, Veit; Gunasekaran, Mekala; Sticht, Heinrich; Tenkerian, Clara; Behrens, Jürgen; Leone, Marina; Engel, Felix; Britzen-Laurent, Nathalie; Naschberger, Elisabeth; Wittenberg, Thomas; Stürzl, Michael (Biochemical Journal, 2018)
Interferon-gamma (IFN-γ) is a pleiotropic cytokine that exerts important functions in inflammation, infectious diseases, and cancer. The large GTPase human guanylate-binding protein 1 (GBP-1) is among the most strongly IFN-γ-induced cellular proteins. Previously, it has been shown that GBP-1 mediates manifold cellular responses to IFN-γ including the inhibition of proliferation, spreading, migration, and invasion and through this exerts anti-tumorigenic activity. However, the mechanisms of GBP-1 anti-tumorigenic activities remain poorly understood. Here, we elucidated the molecular mechanism of the human GBP-1-mediated suppression of proliferation by demonstrating for the first time a cross-talk between the anti-tumorigenic IFN-γ and Hippo pathways. The α9-helix of GBP-1 was found to be sufficient to inhibit proliferation. Protein-binding and molecular modeling studies revealed that the α9-helix binds to the DNA-binding domain of the Hippo signaling transcription factor TEA domain protein (TEAD) mediated by the 376VDHLFQK382 sequence at the N-terminus of the GBP-1-α9-helix. Mutation of this sequence resulted in abrogation of both TEAD interaction and suppression of proliferation. Further on, the interaction caused inhibition of TEAD transcriptional activity associated with the down-regulation of TEAD-target genes. In agreement with these results, IFN-γ treatment of the cells also impaired TEAD activity, and this effect was abrogated by siRNA-mediated inhibition of GBP-1 expression. Altogether, this demonstrated that the α9-helix is the proliferation inhibitory domain of GBP-1, which acts independent of the GTPase activity through the inhibition of the Hippo transcription factor TEAD in mediating the anti-proliferative cell response to IFN-γ.
EVALuna2:34818

IGF-I and Hyaluronic Acid Mitigate the Negative Effect of Irradiation on Human Skin Keratinocytes - Sörgel, Celena; Schmid, Rafael; Stadelmann, Nina; Weisbach, Volker Günter; Distel, Luitpold; Horch, Raymund E.; Kengelbach-Weigand, Annika (Cancers, 2022)
Ionizing radiation has become an integral part of modern cancer therapy regimens. Various side effects, such as radiation dermatitis, affect patients in acute and chronic forms and decrease therapy compliance significantly. In this study, primary keratinocytes were irradiated in a 2-dimensional (2D) culture as well as on a 3-dimensional (3D) collagen-elastin matrix with doses of 2 and 5 Gy. The effect of different concentrations of IGF-I, KGF, platelet lysate (PL), high and low molecular weight hyaluronic acid (H-HA, L-HA), and adipose-derived stem cell (ADSC) conditioned medium was analyzed in respect to cell viability (WST-8), wound closure (migration), and the gene expression (quantitative real-time PCR) of 2D cultures. The 3D culture was evaluated by WST-8. A mixture of H-HA and L-HA, as well as IGF-I, could significantly stimulate the keratinocyte viability and migration which were severely reduced by irradiation. The MKI67and IL6 gene expression of irradiated keratinocytes was significantly higher after H-HA/L-HA treatment. The stimulating effects of H-HA/L-HA and IGF-I were able to be confirmed in 3D culture. A positive influence on cell viability, migration, and gene expression was achieved after the treatment with H-L-HA and IGF-I. These results open the possibility of a novel therapeutic method for both the prevention and the treatment of radiation dermatitis.
CRIS-Team Scopus Importer:2022-02-25
Keywords: Dermatitis; Hyaluronic acid; IGF-I; Irradiation; Keratinocytes; Wound healing

IL-33-induced metabolic reprogramming controls the differentiation of alternatively activated macrophages and the resolution of inflammation - Faas, Maria; Ipseiz, Natacha; Ackermann, Jochen; Culemann, Stephan; Grüneboom, Anika; Schröder, Fenja; Rothe, Tobias; Scholtysek, Carina; Eberhardt, Martin; Böttcher, Martin; Kirchner, Philipp; Stoll, Cornelia; et al. (Immunity, 2021)
Alternatively activated macrophages (AAMs) contribute to the resolution of inflammation and tissue repair. However, molecular pathways that govern their differentiation have remained incompletely understood. Here, we show that uncoupling protein-2-mediated mitochondrial reprogramming and the transcription factor GATA3 specifically controlled the differentiation of pro-resolving AAMs in response to the alarmin IL-33. In macrophages, IL-33 sequentially triggered early expression of pro-inflammatory genes and subsequent differentiation into AAMs. Global analysis of underlying signaling events revealed that IL-33 induced a rapid metabolic rewiring of macrophages that involved uncoupling of the respiratory chain and increased production of the metabolite itaconate, which subsequently triggered a GATA3-mediated AAM polarization. Conditional deletion of GATA3 in mononuclear phagocytes accordingly abrogated IL-33-induced differentiation of AAMs and tissue repair upon muscle injury. Our data thus identify an IL-4-independent and GATA3-dependent pathway in mononuclear phagocytes that results from mitochondrial rewiring and controls macrophage plasticity and the resolution of inflammation.
CRIS-Team Scopus Importer:2021-11-19
Keywords: alternatively activated macrophage; GATA3; interleukin-33; itaconate; mitochondrial rewiring; resolution of inlammation; UCP2; uncoupling

IL-9 and its receptor are predominantly involved in the pathogenesis of UC - Nalleweg, Nancy; Chiriac, Mircea Teodor; Podstawa, Eva; Lehmann, Christian; Rau, Tilman; Atreya, Raja; Krauss, Ekaterina; Hundorfean, Gheorghe; Fichtner-Feigl, Stefan; Hartmann, Arndt; Becker, Christoph; Mudter, Jonas (Gut, 2015)
Several pathogenic roles attributed over the past two decades to either T helper (Th)1 or Th2 cells are increasingly becoming associated with interleukin (IL)-17 and most recently IL-9 signalling. However, the implication of IL-9 in IBD has not been addressed so far.We investigated the expression of IL-9 and IL-9R by using peripheral blood, biopsies and surgical samples. We addressed the functional role of IL-9 signalling by analysis of downstream effector proteins. Using Caco-2 cell monolayers we followed the effect of IL-9 on wound healing.IL-9 mRNA expression was significantly increased in inflamed samples from patients with UC as compared with controls. CD3(+) T cells were major IL-9-expressing cells and some polymorphonuclear leucocytes (PMN) also expressed IL-9. IL-9 was co-localised with the key Th9 transcription factors interferon regulatory factor 4 and PU.1. Systemically, IL-9 was abundantly produced by activated peripheral blood lymphocytes, whereas its receptor was overexpressed on gut resident and circulating PMN. IL-9 stimulation of the latter induced IL-8 production in a dose-dependent manner and rendered PMN resistant to apoptosis suggesting a functional role for IL-9R signalling in the propagation of gut inflammation. Furthermore, IL-9R was overexpressed on gut epithelial cells and IL-9 induced STAT5 activation in these cells. Moreover, IL-9 inhibited the growth of Caco-2 epithelial cell monolayers in wound healing experiments.Our results provide evidence that IL-9 is predominantly involved in the pathogenesis of UC suggesting that targeting IL-9 might become a therapeutic option for patients with UC.
EVALuna2:1839

Immunochemical Detection of Central Nervous Tissue in Retail Meat Products Using Myelin Proteolipid Protein (PLP) as Marker - Hammon, Antje; Düthorn, Tina; Bäuerlein, Rainer; Becker, Cord-Michael; Pischetsrieder, Monika; Pichner, Rohtraud; Gareis, Manfred (Archiv für Lebensmittelhygiene, 2007)
A total of 152 different meat products (emulsion-type sausages, cooked sausages, fermented raw sausages) originating from local butchers shops and supermarkets were analysed for the presence of tissues from the central nervous system (CNS) by a newly developed Western blot assay using myelin proteolipid protein (PLP) as specific marker. Samples tested positive were analysed in parallel with a commercialized ELISA kit based on the detection of glial fibrillary acidic protein (GFAP). Analysing retail meat products by PL Passay, 9.9% of the samples (15 out of 152) showed positive PLP responses. The positive findings were confirmed in five cases (3.3 %) by application of the GFAP-ELISA. With both methods, very strong signals were detected in two sausages originating from a small butcher shop. Repeated sampling and analyses of these products during a period of several months proved the initial findings indicating a systematic contamination or addition of CNS material. The detection of nearly 10 % of CNS-positive sausages demonstrates that intentional or unintentional contaminations of retail meat products are not uncommon. Overall, the PLP assay was confirmed to be a highly sensitive method for the detection of CNS in both heat-treated and raw fermented sausages. Thus it could be applied for routine and food control purposes. © M.&H. Schaper GmbH&Co.
UnivIS-Import:2015-04-14:Pub.2007.nat.dchph.llmch.immuno
Keywords: Central nervous system (CNS); Meat products; Myelin proteolipid protein (PLP); Western blotting

Immunometabolic Determinants of Chemoradiotherapy Response and Survival in Head and Neck Squamous Cell Carcinoma - Krupar, Rosemarie; Hautmann, Matthias G.; Pathak, Ravi R.; Varier, Indu; Mclaren, Cassandra; Gaag, Doris; Hellerbrand, Claus; Evert, Matthias; Laban, Simon; Idel, Christian; Sandulache, Vlad; Perner, Sven; et al. (American Journal of Pathology, 2017)
Tumor immune microenvironment and tumor metabolism are major determinants of chemoradiotherapy response. The interdependency and prognostic significance of specific immune and metabolic phenotypes in head and neck squamous cell carcinoma (HNSCC) were assessed and changes in reactive oxygen species were evaluated as a mechanism of treatment response in tumor spheroid/immunocyte co-cultures. Pretreatment tumor biopsies were immunohistochemically characterized in 73 HNSCC patients treated by definitive chemoradiotherapy and correlated with survival. The prognostic significance of CD8A, GLUT1, and COX5B gene expression was analyzed within The Cancer Genome Atlas database. HNSCC spheroids were co-cultured in vitro with peripheral blood mononuclear cells (PBMCs) in the presence of the glycolysis inhibitor 2-deoxyglucose and radiation treatment followed by PBMC chemotaxis determination via fluorescence microscopy. In the chemoradiotherapy-treated HNSCC cohort, mitochondrial-rich (COX5B) metabolism correlated with increased and glucose-dependent (GLUT1) metabolism with decreased intratumoral CD8/CD4 ratios. High CD8/CD4, together with mitochondrial-rich or glucose-independent metabolism, was associated with improved short-term survival. The Cancer Genome Atlas analysis confirmed that patients with a favorable immune and metabolic gene signature (high CD8A, high COX5B, low GLUT1) had improved short- and long-term survival. In vitro, 2-deoxyglucose and radiation synergistically up-regulated reactive oxygen species-dependent PBMC chemotaxis to HNSCC spheroids. These results suggest that glucose-independent tumor metabolism is associated with CD8-dominant antitumor immune infiltrate, and together, these contribute to improved chemoradiotherapy response in HNSCC.
EVALuna2:4758

Impact of antimuscarinic molecules on MAPK-mediated signal transduction in oligodendroglial myelination - Meszaros, Lisa; Hoffmann, Alana; Wihan, Jeanette; Reiprich, Simone; Winkler, Jürgen (GLIA, 2019)
CRIS-Team WoS Importer:2020-01-10

Impact of CYLD on chromatin structure and histone methylation in malignant melanoma - Schott, Mandy; Kappelmann-Fenz, Melanie; Fischer, Stefan; Fernandez-Barrena, Maite G.; Pineda-Lucena, Antonio; Ávila, Matías A.; Kuphal, Silke; Boßerhoff, Anja Katrin (International Journal of Molecular Medicine, 2022)
The tumor suppressive role of CYLD lysine 63 deubiquitinase (CYLD) is known in melanoma. To the best of our knowledge, however, the precise mechanism under- lying the tumor suppressive function of CYLD has yet to be clarified. In the present study, a novel melanoma mouse model was generated, which revealed accelerated tumor growth in Cyld-knockout (Cyld-/-) compared with Cyld-wild-type (Cyld+/+) mice. To determine the underlying molecular mechanism, mutation analysis of primary tumor-derived cell lines from Cyld+/+and Cyld-/-mice was performed using RNA sequencing data. Variant calling revealed no common mutations in Cyld-/-compared with Cyld+/+cells. Thus, the epigenetic processes influencing development and progression of melanoma were investigated. Initial analysis of expres- sion pattern of known hypermethylated genes in melanoma (suppressor of cytokine signalling, methylthioadenosine phosphorylase, cadherin 1) in the presence or absence of 5'-Aza-deoxyctidine treatment revealed that CYLD does not play a key role in DNA methylation. Chromatin accessibility and histone H3 modification assay uncovered a role of CYLD in the formation of chromatin structure. Subsequent inhibitor experiments confirmed the effect of CYLD on H3K9me2 level associated with heterochromatin. Furthermore, enhanced H3K9 dimethylation in Cyld-/-melanoma cells was associated with upregulation of euchromatic histone lysine methyltrans- ferase 2 (EHMT2). Moreover, the specific inhibitor of EHMT2, CM272, resulted in decreased proliferation and relaxation of compact chromatin in Cyld-deficient melanoma cells. These results reveal a novel role of CYLD in histone methylation and chromatin packaging.
CRIS-Team Scopus Importer:2022-04-15
Keywords: chromatin accessibility; CYLD lysine 63 deubiquitinase; epigenetic; euchromatic histone lysine methyltransferase 2; H3K9me2; Melanoma

Impact of Swiprosin-1/Efhd2 on Adult Hippocampal Neurogenesis - Regensburger, Martin; Prots, Iryna; Reimer, Dorothea; Brachs, Sebastian; Loskarn, Sandra; Lie, Dieter Chichung; Mielenz, Dirk; Winner, Beate (Stem Cell Reports, 2018)
Swiprosin-1/Efhd2 (Efhd2) is highly expressed in the CNS during development and in the adult. EFHD2 is regulated by Ca2+ binding, stabilizes F-actin, and promotes neurite extension. Previous studies indicated a dysregulation of EFHD2 in human Alzheimer's disease brains. We hypothesized a detrimental effect of genetic ablation of Efhd2 on hippocampal integrity and specifically investigated adult hippocampal neurogenesis. Efhd2 was expressed throughout adult neuronal development and in mature neurons. We observed a severe reduction of the survival of adult newborn neurons in Efhd2 knockouts, starting at the early neuroblast stage. Spine formation and dendrite growth of newborn neurons were compromised in full Efhd2 knockouts, but not upon cell-autonomous Efhd2 deletion. Together with our finding of severe hippocampal tauopathy in Efhd2 knockout mice, these data connect Efhd2 to impaired synaptic plasticity as present in Alzheimer's disease and identify a role of Efhd2 in neuronal survival and synaptic integration in the adult hippocampus.
EVALuna2:34019

Impact of the microRNA family miR-204/-211 on the oligodendroglial gene regulatory network - Wittstatt, Jan; Weider, Matthias; Reiprich, Simone; Wegner, Michael (GLIA, 2019)
CRIS-Team WoS Importer:2020-01-10

Impact of transcription factor Sox8 on oligodendrocyte specification in the mouse embryonic spinal cord. - Sock, Elisabeth; Wegner, Michael; Stolt, Claus; et al. (Developmental Biology, 2005)
The myelin-forming oligodendrocytes of the mouse embryonic spinal cord express the three group E Sox proteins Sox8, Sox9, and Sox10. They require Sox9 for their specification from neuroepithelial cells of the ventricular zone and Sox10 for their terminal differentiation and myelination. Here, we show that during oligodendrocyte development, Sox8 is expressed after Sox9, but before Sox10. Loss of Sox8 did not impair oligodendrocyte specification by itself, but enhanced the Sox9-dependent defect. Oligodendrocyte progenitors were still generated in the Sox9-deficient spinal cord, albeit at 20-fold lower rates than in the wildtype. Combined loss of Sox8 and Sox9, in contrast, led to a near complete loss of oligodendrocytes. Other cell types such as ventricular zone cells and radial glia remained unaffected in their numbers as well as their rates of proliferation and apoptosis. Oligodendrocyte development thus relies on the differential contribution of all three group E Sox proteins at various phases. © 2005 Elsevier Inc. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2005.med.IB.LPCIPDBI.impact
Keywords: Glia; High-mobility-group; Knockout; Oligodendrogenesis; Redundancy; Sox10; Sox9; Sry

Impacts of a new trancription factor family: Mammalian GCM proteins in health and disease. - Wegner, Michael; Hashemolhosseini, Said (The Journal of Cell Biology, 2004)
UnivIS-Import:2015-03-09:Pub.2004.med.IB.LPCIPDBI.impact

Importance of the Amino Acid Transporter SNAT1/SLC38A1 in malignant Melanoma - Lörentz, Sandra; Böhme-Schäfer, Ines; Boßerhoff, Anja Katrin (JOURNAL DER DEUTSCHEN DERMATOLOGISCHEN GESELLSCHAFT, 2022)
CRIS-Team WoS Importer:2022-09-23

Importance of the RNA Binding Protein Hu-antigen R in malignant Melanoma - Liebig, Janika; Boßerhoff, Anja Katrin (2018)
EVALuna2:203602

Inactivation of the Mouse L-Proline Transporter PROT Alters Glutamatergic Synapse Biochemistry and Perturbs Behaviors Required to Respond to Environmental Changes - Schulz, Daniel; Morschel, Julia; Schuster, Stefanie; Eulenburg, Volker; Gomeza, Jesus (Frontiers in Molecular Neuroscience, 2018)
The endogenous neutral amino acid L-proline exhibits a variety of physiological and behavioral actions in the nervous system, highlighting the importance of accurately regulating its extracellular abundance. The L-proline transporter PROT (Slc6A7) is believed to control the spatial and temporal distribution of L-proline at glutamatergic synapses by rapid uptake of this amino acid into presynaptic terminals. Despite the importance of members of the Slc6 transporter family regulating neurotransmitter signaling and homeostasis in brain, evidence that PROT dysfunction supports risk for mental illness is lacking. Here we report the disruption of the PROT gene by homologous recombination. Mice defective in PROT displayed altered expression of glutamate transmission-related synaptic proteins in cortex and thalamus. PROT deficiency perturbed mouse behavior, such as reduced locomotor activity, decreased approach motivation and impaired memory extinction. Thus, our study demonstrates that PROT regulates behaviors that are needed to respond to environmental changes in vivo and suggests that PROT dysfunctions might contribute to mental disorders showing altered response choice following task contingency changes.
EVALuna2:35242

In Adult Skeletal Muscles, the Co-Receptors of Canonical Wnt Signaling, Lrp5 and Lrp6, Determine the Distribution and Size of Fiber Types, and Structure and Function of Neuromuscular Junctions - Geßler, Lea; Kurtek, Christopher; Merholz, Mira; Jian, Yongzhi; Hashemolhosseini, Said (Cells, 2022)
Canonical Wnt signaling is involved in skeletal muscle cell biology. The exact way in which this pathway exerts its contribution to myogenesis or neuromuscular junctions (NMJ) is a matter of debate. Next to the common co-receptors of canonical Wnt signaling, Lrp5 and Lrp6, the receptor tyrosine kinase MuSK was reported to bind at NMJs WNT glycoproteins by its extracellular cysteine-rich domain. Previously, we reported canonical Wnt signaling being active in fast muscle fiber types. Here, we used conditional Lrp5 or Lrp6 knockout mice to investigate the role of these receptors in muscle cells. Conditional double knockout mice died around E13 likely due to ectopic expression of the Cre recombinase. Phenotypes of single conditional knockout mice point to a very divergent role for the two receptors. First, muscle fiber type distribution and size were changed. Second, canonical Wnt signaling reporter mice suggested less signaling activity in the absence of Lrps. Third, expression of several myogenic marker genes was changed. Fourth, NMJs were of fragmented phenotype. Fifth, recordings revealed impaired neuromuscular transmission. In sum, our data show fundamental differences in absence of each of the Lrp co-receptors and suggest a differentiated view of canonical Wnt signaling pathway involvement in adult skeletal muscle cells.
CRIS-Team WoS Importer:2023-01-20

Increased expression of pregnancy-associated plasma protein-A in activated hepatic stellate cells is a potential therapeutic target and serum marker of hepatic fibrosis - Kim, F.; Hellerbrand, Claus (JOURNAL OF HEPATOLOGY, 2018)
CRIS-Team WoS Importer:2019-03-26

In-depth virological and immunological characterization of HIV-1 cure after CCR5Δ32/Δ32 allogeneic hematopoietic stem cell transplantation - Jensen, Björn Erik Ole; Knops, Elena; Cords, Leon; Lübke, Nadine; Salgado, Maria; Busman-Sahay, Kathleen; Estes, Jacob D.; Huyveneers, Laura E.P.; Perdomo-Celis, Federico; Wittner, Melanie; Gálvez, Cristina; Mummert, Christiane; et al. (Nature Medicine, 2023)
Despite scientific evidence originating from two patients published to date that CCR5Δ32/Δ32 hematopoietic stem cell transplantation (HSCT) can cure human immunodeficiency virus type 1 (HIV-1), the knowledge of immunological and virological correlates of cure is limited. Here we characterize a case of long-term HIV-1 remission of a 53-year-old male who was carefully monitored for more than 9 years after allogeneic CCR5Δ32/Δ32 HSCT performed for acute myeloid leukemia. Despite sporadic traces of HIV-1 DNA detected by droplet digital PCR and in situ hybridization assays in peripheral T cell subsets and tissue-derived samples, repeated ex vivo quantitative and in vivo outgrowth assays in humanized mice did not reveal replication-competent virus. Low levels of immune activation and waning HIV-1-specific humoral and cellular immune responses indicated a lack of ongoing antigen production. Four years after analytical treatment interruption, the absence of a viral rebound and the lack of immunological correlates of HIV-1 antigen persistence are strong evidence for HIV-1 cure after CCR5Δ32/Δ32 HSCT.
CRIS-Team Scopus Importer:2023-03-03

Induction of exportin-5 expression during melanoma development supports the cellular behavior of human malignant melanoma cells - Ott, Corinna; Linck, Lisa; Kremmer, Elisabeth; Meister, Gunter; Boßerhoff, Anja Katrin (Oncotarget, 2016)
Regulation of gene expression via microRNAs is known to promote the development of many types of cancer. In melanoma, miRNAs are globally up-regulated, and alterations of miRNA-processing enzymes have already been identified. However, mis-regulation of miRNA transport has not been analyzed in melanoma yet. We hypothesized that alterations in miRNA transport disrupt miRNA processing. Therefore, we investigated whether the pre-miRNA transporter Exportin-5 (XPO5) was involved in altered miRNA maturation and functional consequences in melanoma. We found that XPO5 is significantly over-expressed in melanoma compared with melanocytes. We showed enhanced XPO5 mRNA stability in melanoma cell lines which likely contributes to up-regulated XPO5 protein expression. In addition, we identified MEK signaling as a regulator of XPO5 expression in melanoma. Knockdown of XPO5 expression in melanoma cells led to decreased mature miRNA levels and drastic functional changes. Our data revealed that aberrant XPO5 expression is important for the maturation of miRNAs and the malignant behavior of melanoma cells. We suggest that the high abundance of XPO5 in melanoma leads to enhanced survival, proliferation and metastasis and thereby supports the aggressiveness of melanoma.
EVALuna2:4732

Induction of oligodendrocyte differentiation by Olig2 and Sox10: evidence for reciprocal interactions and dosage-dependent mechanisms. - Wegner, Michael; et al. (Developmental Biology, 2007)
Recent studies have suggested that oligodendrocyte development is likely to be under the control of a hierarchy of lineage-specific transcription factors. In the developing mouse spinal cord, expression of Olig2, Sox10 and Nkx2.2 is sequentially up-regulated in cells of oligodendrocyte lineage. These transcription factors play essential roles in oligodendrocyte specification and differentiation. However, the regulatory relationship and functional interactions among these transcription factors have not been determined. In this study, we systematically investigated the function and hierarchical relationship of Olig2, Sox10 and Nkx2.2 transcription factors in the control of oligodendrocyte differentiation. It was found that over-expression of Olig2 is sufficient to induce Sox10, Nkx2.2 and precocious oligodendrocyte differentiation in embryonic chicken spinal cord. Sox10 expression alone is also sufficient to stimulate ectopic oligodendrocyte differentiation and weakly induce Nkx2.2 expression. Although genetic evidence indicated that Sox10 functions downstream of Olig2, Sox10 activity can modulate Olig2 expression. In addition, we presented evidence that the control of oligodendrocyte differentiation by Olig2, Sox10 and Nkx2.2 is a dosage-dependent developmental process and can be affected by both haploinsufficiency and over-dosage. © 2006 Elsevier Inc. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2007.med.IB.LPCIPDBI.induct
Keywords: Gene expression; In ovo electroporation; Mutation; Myelin genes; Nkx2.2; Spinal cord

Infantile epileptic encephalopathy, transient choreoathetotic movements, and hypersomnia due to a De Novo missense mutation in the SCN2A gene - Hackenberg, Annette; Baumer, Alessandra; Sticht, Heinrich; Schmitt, Bernhard; Kroell-Seger, Judith; Wille, David; Joset, Pascal; Papuc, Sorina; Rauch, Anita; Plecko, Barbara (Neuropediatrics, 2014)
Mutations of the SCN2A gene have originally been described in association with benign familial neonatal-infantile seizures (BFNIS). Recently, single patients with more severe phenotypes and persisting epileptic encephalopathies have been recognized. We report the case of a girl with severe infantile onset epileptic encephalopathy and a de novo missense mutation in the SCN2A gene (c.4025T > C/ = ; p.L1342P/ = ), who presented with a transient choreatic movement disorder, hypersomnia, and progressive brain atrophy. Whole exome sequencing did not reveal any other disease causing mutation. Our patient contributes to the expanding phenotypic spectrum of SCN2A-related disorders and underlines the importance of genetic workup in epileptic encephalopathies.
EVALuna2:26283

Infiltrating T lymphocytes reduce myeloid phagocytosis activity in synucleinopathy model - Sommer, Annika; Fadler, Tanja; Dorfmeister, Eva; Hoffmann, Anna-Carin; Xiang, Wei; Winner, Beate; Prots, Iryna (Journal of Neuroinflammation, 2016)
Synucleinopathies comprise a group of neurodegenerative diseases associated with abnormal accumulation of ?-synuclein. One of the key factors that contribute to the progression of synucleinopathies is neuroinflammation. However, the role of lymphocytes in synucleinopathies like Parkinson's disease (PD) remains largely unclear.To investigate how lymphocytes impact synucleinopathies, human wild-type ?-synuclein (WTS) transgenic mice were crossed with mice lacking mature lymphocytes (Rag2(-/-)). In this in vivo model, we quantified ?-synuclein aggregation in the substantia nigra (SN) and striatum and determined the numbers of innate and adaptive immune cells in the central nervous system (CNS). The activation state of resident and infiltrated CNS myeloid cells (M1 vs. M2) was further classified by gene and protein expression analyses. The impact of T and B lymphocytes on the phagocytic activity of microglia in the presence of ?-synuclein aggregates was addressed in BV2 microglia in vitro.Compared to WTS(+) Rag2(+/+) mice, where T but not B lymphocytes infiltrated the CNS, decreased amounts of ?-synuclein aggregates were found in WTS(+) Rag2(-/-) mice devoid of mature lymphocytes. The presence of T lymphocytes did not alter the number of Iba1(+) microglia but increased the frequency of the CD11b(+) CD45(hi) population in the CNS, indicative of an increased number of infiltrated macrophages. Moreover, the M1 phenotype was more prominent in WTS(+) Rag2(+/+) mice, whereas the M2 activation state was dominating in the absence of lymphocytes in WTS(+) Rag2(-/-) mice. In vitro, in the presence of T but not B lymphocytes, significantly less ?-synuclein was phagocytosed by BV2 microglia, further supporting the prevalence of the M1 phenotype in the presence of T lymphocytes.Peripheral T lymphocytes strongly contribute to increased ?-synuclein pathology via modulation of CNS myeloid cell function. In the presence of T lymphocytes, microglia phagocytosis of aggregated ?-synuclein is reduced, which increases the severity of synucleinopathy.
EVALuna2:4741

Influence of chromatin remodeler Ep400 on oligodendroglial development - Elsesser, Olga; Wegner, Michael (GLIA, 2019)
CRIS-Team WoS Importer:2020-01-10

Influence of different irradiation protocols on vascularization and bone formation parameters in rat femora. - Rottensteiner-Brandl, Ulrike; Distel, Luitpold; Stumpf, Martin; Fey, Tobias; Köhn, Katrin; Bertram, Ulf; Lingens, Lara; Greil, Peter; Horch, Raymund E.; Arkudas, Andreas (Tissue Engineering - Part C: Methods, 2017)
INTRODUCTION Aim of the present study was the establishment of an efficient and reproducible model for irradiation of rat femora as a model for impaired osteogenesis and angiogenesis. MATERIALS AND METHODS Four different irradiation protocols were compared: single irradiation of the left femur with 20 Gy and explantation after 4 or 8 weeks (group A, B); three irradiation fractions at 3-4 days intervals with 10 Gy and explantation after 4 or 8 weeks (group C, D). The contralateral, unirradiated femur served as control. Evaluation included histology, microcomputertomography (μCT) and real time PCR. RESULTS Histology showed a pronounced increase of vacuoles in bone marrow after irradiation, especially after 4 weeks (group A and C), demonstrating bone marrow edema and fatty degeneration. Irradiation provoked a decrease of total cell numbers in cortical bone and of Hif1α positive cells in bone marrow. The expression of several markers (osteocalcin, RUNX2, TGFβ1, TNFα, VEGF-A, Hif1α) was decreased in group A after irradiation. This might suggest a decreased metabolism after irradiation. A significant decrease in small-sized vessels was seen in μCT evaluation in group A and D. CONCLUSIONS Single irradiation with 20 Gy had the most severe and reproducible impact on osteogenesis and angiogenesis after 4 weeks while being well tolerated by all animals, thus making it an excellent model for evaluation of bone healing and vascularization in irradiated tissu
Keywords: irradiation model; bone tissue engineering; angiogenesis; osteogenesis

Inhibition of monoacylglycerol lipase for the treatment of liver disease: tempting but still playing with fire - Hellerbrand, Claus (Gut, 2019)
CRIS-Team WoS Importer:2019-07-09

Inhibition of mTORC2/RICTOR Impairs Melanoma Hepatic Metastasis - Schmidt, Katharina M.; Dietrich, Peter; Hackl, Christina; Guenzle, Jessica; Bronsert, Peter; Wagner, Christine; Fichtner-Feigl, Stefan; Schlitt, Hans J.; Geissler, Edward K.; Hellerbrand, Claus; Lang, Sven A. (Neoplasia, 2018)
Mammalian target of rapamycin complex 2 (mTORC2) with its pivotal component rapamycin-insensitive companion of mTOR (RICTOR) is the major regulator of AKT phosphorylation and is increasingly implicated in tumor growth and progression. In cutaneous melanoma, an extremely aggressive and highly metastatic disease, RICTOR overexpression is involved in tumor development and invasiveness. Therefore, we investigated the impact of RICTOR inhibition in melanoma cells in vitro and in vivo with special emphasis on hepatic metastasis. Moreover, our study focused on the interaction of tumor cells and hepatic stellate cells (HSC) which play a crucial role in the hepatic microenvironment. In silico analysis revealed increased RICTOR expression in melanoma cells and tissues and indicated higher expression in advanced melanoma stages and metastases. In vitro, transient RICTOR knock-down via siRNA caused a significant reduction of tumor cell motility. Using a syngeneic murine splenic injection model, a significant decrease in liver metastasis burden was detected in vivo. Moreover, stimulation of melanoma cells with conditioned medium (CM) from activated HSC or hepatocyte growth factor (HGF) led to a significant induction of AKT phosphorylation and tumor cell motility. Blocking of RICTOR expression in cancer cells diminished constitutive and HGF-induced AKT phosphorylation as well as cell motility. Interestingly, RICTOR blockade also led to an abrogation of CM-induced effects on AKT phosphorylation and motility in melanoma cells. In conclusion, these results provide first evidence for a critical role of mTORC2/RICTOR in melanoma liver metastasis via cancer cell/HSC interactions.
EVALuna2:35129

Inhibition of peptidyl-prolyl isomerase (PIN1) and BRAF signaling to target melanoma - Braun, Christina; Schneider, Nadja; Pei, Dehua; Boßerhoff, Anja Katrin; Kuphal, Silke (American Journal of Translational Research, 2019)
PIN1 is a phosphorylation-dependent peptidyl-prolyl cis/trans isomerase, overexpressed in many cancers, including melanoma. Our immunohistochemistry data of melanoma patient tissue underline the up-regulation of PIN1 in metastases. Here, we demonstrate important functions of PIN1 and its selective and cell permeable inhibitor 37 for the treatment of melanoma. To analyze its possible role in oncogenesis and as a therapeutic target, we first suppressed PIN1 expression by a siRNA pool. PIN1 knockdown potently inhibited melanoma cell proliferation and vascular mimicry by influencing several cancer-relevant pathways. Furthermore, inhibitor 37 inhibited cell growth in melanoma and induced apoptosis. Normal healthy melanocytes, keratinocytes and fibroblasts are not affected by the PIN1 inhibitor 37. Combinatorial treatment of melanoma cells is with Vemurafenib as a common therapeutic option for BRAF-mutated melanoma and inhibitor 37 resulted in a strong, synergistic effect on apoptosis of melanoma cell lines. In summary, targeting PIN1 offers a promising therapeutic approach to simultaneously downregulate multiple cancer-driving pathways in cancer.
CRIS-Team WoS Importer:2019-08-09

Inhibition of RAS activation due to a homozygous ezrin variant in patients with profound intellectual disability - Riecken, Lars Bjoern; Tawamie, Hasan; Dornblut, Carsten; Buchert, Rebecca; Ismayel, Amina; Schulz, Alexander; Schumacher, Johannes; Sticht, Heinrich; Pohl, Katja J.; Cui, Yan; Reis, André; Morrison, Helen; et al. (Human Mutation, 2015)
Gain-of-function alterations in several components and modulators of the Ras-MAPK pathway lead to dysregulation of the pathway and cause a broad spectrum of autosomal dominant developmental disorders, collectively known as RASopathies. These findings demonstrate the importance of tight multilevel Ras regulation to safeguard signaling output and prevent aberrant activity. We have recently identified ezrin as a novel regulatory element required for Ras activation. Homozygosity mapping and exome sequencing have now revealed the first presumably disease-causing variant in the coding gene EZR in two siblings with a profound intellectual disability. Localization and membrane targeting of the altered ezrin protein appeared normal but molecular modeling suggested protein interaction surfaces to be disturbed. Functional analysis revealed that the altered ezrin protein is no longer able to bind Ras and facilitate its activation. Furthermore, expression of the altered ezrin protein in different cell lines resulted in abnormal cellular processes, including reduced proliferation and neuritogenesis, thus revealing a possible mechanism for its phenotype in humans. To our knowledge, this is the first report of an autosomal recessively inherited loss-of-function mutation causing reduced Ras activity and thus extends and complements the pathogenicity spectrum of known Ras-MAPK pathway disturbances.
EVALuna2:9253

Inhibition of SARS CoV Envelope Protein by Flavonoids and Classical Viroporin Inhibitors - Breitinger, Ulrike; Ali, Nourhan K.M.; Sticht, Heinrich; Breitinger, Hans Georg (Frontiers in Microbiology, 2021)
Severe acute respiratory syndrome coronavirus (SARS-CoV), an enveloped single-stranded positive-sense RNA virus, is a member of the genus Betacoronavirus, family Coronaviridae. The SARS-CoV envelope protein E is a small (∼8.4 kDa) channel-forming membrane protein whose sequence is highly conserved between SARS-CoV and SARS-CoV-2. As a viroporin, it is involved in various aspects of the virus life cycle including assembly, budding, envelope formation, virus release, and inflammasome activation. Here, SARS-CoV E protein was recombinantly expressed in HEK293 cells and channel activity and the effects of viroporin inhibitors studied using patch-clamp electrophysiology and a cell viability assay. We introduced a membrane-directing signal peptide to ensure transfer of recombinant E protein to the plasma membrane. E protein expression induced transmembrane currents that were blocked by various inhibitors. In an ion-reduced buffer system, currents were proton-dependent and blocked by viroporin inhibitors rimantadine and amantadine. I-V relationships of recombinant E protein were not pH-dependent in a classical buffer system with high extracellular Na+ and high intracellular K+. E-protein mediated currents were inhibited by amantadine and rimantadine, as well as 5-(N,N-hexamethylene)amiloride (HMA). We tested a total of 10 flavonoids, finding inhibitory activity of varying potency. Epigallocatechin and quercetin were most effective, with IC50 values of 1.5 ± 0.1 and 3.7 ± 0.2 nM, respectively, similar to the potency of rimantadine (IC50 = 1.7 ± 0.6 nM). Patch-clamp results were independently verified using a modified cell viability assay for viroporin inhibitors. These results contribute to the development of novel antiviral drugs that suppress virus activity and proliferation.
CRIS-Team Scopus Importer:2021-08-06
Keywords: cell viability assay; E protein; ion channel inhibitors; patch-clamp electrophysiology; SARS CoV-1; viroporins

Inhibitory Effects of Green Tea and (-)-Epigallocatechin Gallate on Transport by OATP1B1, OATP1B3, OCT1, OCT2, MATE1, MATE2-K and P-Glycoprotein - Knop, Jana; Misaka, Shingen; Singer, Katrin; Hoier, Eva; Müller, Fabian; Gläser, Hartmut; König, Jörg; Fromm, Martin (PLoS ONE, 2015)
Green tea catechins inhibit the function of organic anion transporting polypeptides (OATPs) that mediate the uptake of a diverse group of drugs and endogenous compounds into cells. The present study was aimed at investigating the effect of green tea and its most abundant catechin epigallocatechin gallate (EGCG) on the transport activity of several drug transporters expressed in enterocytes, hepatocytes and renal proximal tubular cells such as OATPs, organic cation transporters (OCTs), multidrug and toxin extrusion proteins (MATEs), and P-glycoprotein (P-gp). Uptake of the typical substrates metformin for OCTs and MATEs and bromosulphophthalein (BSP) and atorvastatin for OATPs was measured in the absence and presence of a commercially available green tea and EGCG. Transcellular transport of digoxin, a typical substrate of P-gp, was measured over 4 hours in the absence and presence of green tea or EGCG in Caco-2 cell monolayers. OCT1-, OCT2-, MATE1- and MATE2-K-mediated metformin uptake was significantly reduced in the presence of green tea and EGCG (P < 0.05). BSP net uptake by OATP1B1 and OATP1B3 was inhibited by green tea [IC50 2.6% (v/v) and 0.39% (v/v), respectively]. Green tea also inhibited OATP1B1- and OATP1B3-mediated atorvastatin net uptake with IC50 values of 1.9% (v/v) and 1.0% (v/v), respectively. Basolateral to apical transport of digoxin was significantly decreased in the presence of green tea and EGCG. These findings indicate that green tea and EGCG inhibit multiple drug transporters in vitro. Further studies are necessary to investigate the effects of green tea on prototoypical substrates of these transporters in humans, in particular on substrates of hepatic uptake transporters (e.g. statins) as well as on P-glycoprotein substrates.
EVALuna2:8693

Inhibitory glycine receptors: an update - Dutertre, Sebastien; Becker, Cord-Michael; Betz, Heinrich (Journal of Biological Chemistry, 2012)
Strychnine-sensitive glycine receptors (GlyRs) mediate synaptic inhibition in the spinal cord, brainstem, and other regions of the mammalian central nervous system. In this minireview, we summarize our current view of the structure, ligand-binding sites, and chloride channel of these receptors and discuss recently emerging functions of distinct GlyR isoforms. GlyRs not only regulate the excitability of motor and afferent sensory neurons, including pain fibers, but also are involved in the processing of visual and auditory signals. Hence, GlyRs constitute promising targets for the development of therapeutically useful compounds.
EVALuna2:4682

Injury-activated glial cells promote wound healing of the adult skin in mice. - Parfejevs, Vadims; Debbache, Julien; Shakhova, Olga; Schaefer, Simon M.; Glausch, Mareen; Wegner, Michael; Suter, Ueli; Riekstina, Una; Werner, Sabine; Sommer, Lukas (Nature Communications, 2018)
Cutaneous wound healing is a complex process that aims to re-establish the original structure of the skin and its functions. Among other disorders, peripheral neuropathies are known to severely impair wound healing capabilities of the skin, revealing the importance of skin innervation for proper repair. Here, we report that peripheral glia are crucially involved in this process. Using a mouse model of wound healing, combined with in vivo fate mapping, we show that injury activates peripheral glia by promoting de-differentiation, cell-cycle re-entry and dissemination of the cells into the wound bed. Moreover, injury-activated glia upregulate the expression of many secreted factors previously associated with wound healing and promote myofibroblast differentiation by paracrine modulation of TGF-β signalling. Accordingly, depletion of these cells impairs epithelial proliferation and wound closure through contraction, while their expansion promotes myofibroblast formation. Thus, injury-activated glia and/or their secretome might have therapeutic potential in human wound healing disorders.
UnivIS-Import:2018-09-05:Pub.2018.med.IB.LPCIPDBI.injury

In mammalian skeletal muscle, phosphorylation of TOMM22 by protein kinase CSNK2/CK2 controls mitophagy - Kravic, Bojana; Harbauer, Angelika B.; Romanello, Vanina; Simeone, Luca; Vögtle, F. Nora; Kaiser, Tobias; Straubinger, Marion; Huraskin, Danyil; Böttcher, Martin; Cerqua, Cristina; Martin, Eva Denise; Poveda-Huertes, Daniel; et al. (Autophagy, 2017)
In yeast, Tom22 the central component of the TOMM (translocase of outer mitochondrial membrane) receptor complex is responsible for the recognition and translocation of synthesized mitochondrial precursor proteins, and its protein kinase CK2-dependent phosphorylation is mandatory for TOMM complex biogenesis and proper mitochondrial protein import. In mammals, the biological function of protein kinase CSNK2/CK2 remains vastly elusive and it is unknown whether CSNK2-dependent phosphorylation of TOMM protein subunits has a similar role as that in yeast. To address this issue, we used a skeletal muscle-specific Csnk2b/Ck2?-conditional knockout (cKO) mouse model. Phenotypically, these skeletal muscle Csnk2b cKO mice showed reduced muscle strength and abnormal metabolic activity of mainly oxidative muscle fibers, which point towards mitochondrial dysfunction. Enzymatically, active muscle lysates from skeletal muscle Csnk2b cKO mice phosphorylate murine TOMM22, the mammalian ortholog of yeast Tom22, to a lower extent than lysates prepared from controls. Mechanistically, CSNK2-mediated phosphorylation of TOMM22 changes its binding affinity for mitochondrial precursor proteins. However, in contrast to yeast, mitochondrial protein import seems not to be affected in vitro using mitochondria isolated from muscles of skeletal muscle Csnk2b cKO mice. PINK1, a mitochondrial health sensor that undergoes constitutive import under physiological conditions, accumulates within skeletal muscle Csnk2b cKO fibers and labels abnormal mitochondria for removal by mitophagy as demonstrated by the appearance of mitochondria-containing autophagosomes through electron microscopy. Mitophagy can be normalized by either introduction of a phosphomimetic TOMM22 mutant in cultured myotubes, or by in vivo electroporation of phosphomimetic Tomm22 into muscles of mice. Importantly, transfection of the phosphomimetic Tomm22 mutant in muscle cells with ablated Csnk2b restored their oxygen consumption rate comparable to wild-type levels. In sum, our data show that mammalian CSNK2-dependent phosphorylation of TOMM22 is a critical switch for mitophagy and reveal CSNK2-dependent physiological implications on metabolism, muscle integrity and behavior.
EVALuna2:25775

Innate extracellular vesicles from melanoma patients suppress beta-catenin in tumor cells by miRNA-34a - Lee, Jung-Hyun; Dindorf, Jochen; Eberhardt, Martin; Lai, Xin; Ostalecki, Christian; Koliha, Nina; Gross, Stefani; Blume, Katja; Bruns, Heiko; Wild, Stefan; Schuler, Gerold; Vera, Julio; et al. (Life Science Alliance, 2019)
Upon tumor development, new extracellular vesicles appear in circulation. Our knowledge of their relative abundance, function, and overall impact on cancer development is still preliminary. Here, we demonstrate that plasma extracellular vesicles (pEVs) of non-tumor origin are persistently increased in untreated and post-excision melanoma patients, exhibiting strong suppressive effects on the proliferation of tumor cells. Plasma vesicle numbers, miRNAs, and protein levels were elevated two-to tenfold and detected many years after tumor resection. The vesicles revealed individual and clinical stage-specific miRNA profiles as well as active ADAM10. However, whereas pEV from patients preventing tumor relapse down-regulated beta-catenin and blocked tumor cell proliferation in an miR-34a-dependent manner, pEV from metastatic patients lost this ability and stimulated beta-catenin-mediated transcription. Cancer-induced pEV may constitute an innate immune mechanismsuppressing tumor cell activity including that of residual cancer cells present after primary surgery.
CRIS-Team WoS Importer:2019-05-17

In Silico Study of Camptothecin-Based Pro-Drugs Binding to Human Carboxylesterase 2 - Beierlein, Frank; Horn, Anselm; Sticht, Heinrich; Mokhir, Andriy; Imhof, Petra (Biomolecules, 2024)
Pro-drugs, which ideally release their active compound only at the site of action, i.e., in a cancer cell, are a promising approach towards an increased specificity and hence reduced side effects in chemotherapy. A popular form of pro-drugs is esters, which are activated upon their hydrolysis. Since carboxylesterases that catalyse such a hydrolysis reaction are also abundant in normal tissue, it is of great interest whether a putative pro-drug is a probable substrate of such an enzyme and hence bears the danger of being activated not just in the target environment, i.e., in cancer cells. In this work, we study the binding mode of carboxylesters of the drug molecule camptothecin, which is an inhibitor of topoisomerase I, of varying size to human carboxylesterase 2 (HCE2) by molecular docking and molecular dynamics simulations. A comparison to irinotecan, known to be a substrate of HCE2, shows that all three pro-drugs analysed in this work can bind to the HCE2 protein, but not in a pose that is well suited for subsequent hydrolysis. Our data suggest, moreover, that for the irinotecan substrate, a reactant-competent pose is stabilised once the initial proton transfer from the putative nucleophile Ser202 to the His431 of the catalytic triad has already occurred. Our simulation work also shows that it is important to go beyond the static models obtained from molecular docking and include the flexibility of enzyme–ligand complexes in solvents and at a finite temperature. Under such conditions, the pro-drugs studied in this work are unlikely to be hydrolysed by the HCE2 enzyme, indicating a low risk of undesired drug release in normal tissue.
CRIS-Team Scopus Importer:2024-03-08
Keywords: camptothecin; docking; homology model; human carboxylesterase; molecular dynamics simulations; pro-drug

In Skeletal Muscle Fibers, Protein Kinase Subunit CSNK2A1/CK2 alpha Is Required for Proper Muscle Homeostasis and Structure and Function of Neuromuscular Junctions - Merholz, Mira; Jian, Yongzhi; Wimberg, Johannes; Geßler, Lea; Hashemolhosseini, Said (Cells, 2022)
CSNK2 tetrameric holoenzyme is composed of two subunits with catalytic activity (CSNK2A1 and/or CSNK2A2) and two regulatory subunits (CSNK2B) and is involved in skeletal muscle homeostasis. Up-to-date, constitutive Csnk2a2 knockout mice demonstrated mild regenerative impairments in skeletal muscles, while conditional Csnk2b mice were linked to muscle weakness, impaired neuromuscular transmission, and metabolic and autophagic compromises. Here, for the first time, skeletal muscle-specific conditional Csnk2a1 mice were generated and characterized. The ablation of Csnk2a1 expression was ensured using a human skeletal actin-driven Cre reporter. In comparison with control mice, first, conditional knockout of CSNK2A1 resulted in age-dependent reduced grip strength. Muscle weakness was accompanied by impaired neuromuscular transmission. Second, the protein amount of other CSNK2 subunits was aberrantly changed. Third, the number of central nuclei in muscle fibers indicative of regeneration increased. Fourth, oxidative metabolism was impaired, reflected by an increase in cytochrome oxidase and accumulation of mitochondrial enzyme activity underneath the sarcolemma. Fifth, autophagic processes were stimulated. Sixth, NMJs were fragmented and accompanied by increased synaptic gene expression levels. Altogether, knockout of Csnk2a1 or Csnk2b results in diverse impairments of skeletal muscle biology.
CRIS-Team WoS Importer:2023-01-06

Interaction among SOX10, PAX3 and MITF, three genes altered in Waardenburg syndrome - Sock, Elisabeth; Wegner, Michael; et al. (Human Molecular Genetics, 2000)
Waardenburg syndrome (WS) is an autosomal dominant disorder with an incidence of 1 in 40 000 that manifests with sensorineural deafness and pigmentation defects. It is classified into four types depending on the presence or absence of additional symptoms. WS1 and WS3 are due to mutations in the PAX3 gene whereas some WS2 cases are associated with mutations in the microphthalmia-associated transcription factor (MITF) gene. The WS4 phenotype can result from mutations in the endothelin-B receptor gene (EDNRB), in the gene for its ligand, endothelin-3 (EDN3), or in the SOX10 gene. PAX3 has been shown to regulate MITF gene expression. The recent implication of SOX10 in WS4 prompted us to test whether this transcription factor, known to cooperate in vitro with PAX3, is also able to regulate expression from the MITF promoter. Here we show that SOX10, in synergy with PAX3, strongly activates MITF expression in transfection assays. Analyses revealed that PAX3 and SOX10 interact directly by binding to a proximal region of the MITF promoter containing binding sites for both factors. Moreover, SOX10 or PAX3 mutant proteins fail to transactivate this promoter, providing further evidence that the two genes act in concert to directly regulate expression of MITF. In situ hybridization experiments carried out in the dominant megacolon (Dom) mouse, confirmed that SOX10 dysfunction impairs Mitf expression as well as melanocytic development and survival. These experiments, which demonstrate an interaction between three of the genes that are altered in WS, could explain the auditory-pigmentary symptoms of this disease.
UnivIS-Import:2015-03-05:Pub.2000.med.IB.LPCIPDBI.intera

Interaction, Cooperative Promoter Modulation and Renal Colocalisation of GCMa and Pitx2. - Wegner, Michael; et al. (Journal of Biological Chemistry, 2004)
UnivIS-Import:2015-03-09:Pub.2004.med.IB.LPCIPDBI.intera

Interaction of Alpha Synuclein and Microtubule Organization Is Linked to Impaired Neuritic Integrity in Parkinson’s Patient-Derived Neuronal Cells - Schneider, Yanni; Drobny, Alice; Prots, Iryna; Zunke, Friederike; Xiang, Wei; Seebauer, Lukas; Schneider, Yanni; Drobny, Alice; Ploetz, Sonja; Koudelka, Tomas; Tholey, Andreas; Prots, Iryna; et al. (International Journal of Molecular Sciences, 2022)
Parkinson’s disease (PD) is neuropathologically characterized by the loss of dopaminergic neurons and the deposition of aggregated alpha synuclein (aSyn). Mounting evidence suggests that neuritic degeneration precedes neuronal loss in PD. A possible underlying mechanism could be the interference of aSyn with microtubule organization in the neuritic development, as implied by sev-eral studies using cell-free model systems. In this study, we investigate the impact of aSyn on mi-crotubule organization in aSyn overexpressing H4 neuroglioma cells and midbrain dopaminergic neuronal cells (mDANs) generated from PD patient-derived human induced pluripotent stem cells (hiPSCs) carrying an aSyn gene duplication (SNCADupl). An unbiased mass spectrometric analysis reveals a preferential binding of aggregated aSyn conformers to a number of microtubule elements. We confirm the interaction of aSyn with beta tubulin III in H4 and hiPSC-derived mDAN cell model systems, and demonstrate a remarkable redistribution of tubulin isoforms from the soluble to insoluble fraction, accompanied by a significantly increased insoluble aSyn level. Concordantly, SNCA-Dupl mDANs show impaired neuritic phenotypes characterized by perturbations in neurite initiation and outgrowth. In summary, our findings suggest a mechanistic pathway, through which aSyn aggregation interferes with microtubule organization and induces neurite impairments.
CRIS-Team Scopus Importer:2022-02-11
Keywords: Alpha-synuclein; IPSC; Microtubule; Neurite; Neurodegeneration; Parkinson’s disease; SNCA duplication

Interaction of Glycolipids with the Macrophage Surface Receptor Mincle - a Systematic Molecular Dynamics Study - Söldner, Christian; Horn, Anselm; Sticht, Heinrich (Scientific Reports, 2018)
Synthetic analogues of mycobacterial trehalose-dimycolate such as trehalose acyl esters have been proposed as novel adjuvants for vaccination. They induce an immune response by binding to the macrophage C-type lectin receptor Mincle. The binding site of trehalose is known, but there is yet only very limited structural information about the binding mode of the acyl esters. Here, we performed a systematic molecular dynamics study of trehalose mono-and diesters with different chain lengths. All acyl chains investigated exhibited a high flexibility and interacted almost exclusively with a hydrophobic groove on Mincle. Despite the limited length of this hydrophobic groove, the distal parts of the longer monoesters can still form additional interactions with this surface region due to their conformational flexibility. In diesters, a certain length of the second acyl chain is required to contact the hydrophobic groove. However, a stable concomitant accommodation of both acyl chains in the groove is hampered by the conformational rigidity of Mincle. Instead, multiple dynamic interaction modes are observed, in which the second acyl chain contributes to binding. This detailed structural information is considered helpful for the future design of more affine ligands that may foster the development of novel adjuvants.
EVALuna2:35495

Intestinal fungi contribute to development of alcoholic liver disease - Yang, An-Ming; Inamine, Tatsuo; Hochrath, Katrin; Chen, Peng; Wang, Lirui; Llorente, Cristina; Bluemel, Sena; Hartmann, Phillipp; Xu, Jun; Koyama, Yukinori; Kisseleva, Tatiana; Torralba, Manolito G.; et al. (Journal of Clinical Investigation, 2017)
Chronic liver disease with cirrhosis is the 12th leading cause of death in the United States, and alcoholic liver disease accounts for approximately half of all cirrhosis deaths. Chronic alcohol consumption is associated with intestinal bacterial dysbiosis, yet we understand little about the contribution of intestinal fungi, or mycobiota, to alcoholic liver disease. Here we have demonstrated that chronic alcohol administration increases mycobiota populations and translocation of fungal ?-glucan into systemic circulation in mice. Treating mice with antifungal agents reduced intestinal fungal overgrowth, decreased ?-glucan translocation, and ameliorated ethanol-induced liver disease. Using bone marrow chimeric mice, we found that ?-glucan induces liver inflammation via the C-type lectin-like receptor CLEC7A on Kupffer cells and possibly other bone marrow-derived cells. Subsequent increases in IL-1? expression and secretion contributed to hepatocyte damage and promoted development of ethanol-induced liver disease. We observed that alcohol-dependent patients displayed reduced intestinal fungal diversity and Candida overgrowth. Compared with healthy individuals and patients with non-alcohol-related cirrhosis, alcoholic cirrhosis patients had increased systemic exposure and immune response to mycobiota. Moreover, the levels of extraintestinal exposure and immune response correlated with mortality. Thus, chronic alcohol consumption is associated with an altered mycobiota and translocation of fungal products. Manipulating the intestinal mycobiome might be an effective strategy for attenuating alcohol-related liver disease.
EVALuna2:4754

Intracellular alpha-synuclein affects early maturation of primary oligodendrocyte progenitor cells - Ettle, Benjamin; Reiprich, Simone; Deußer, Janina; Schlachetzki, Johannes; Xiang, Wei; Prots, Iryna; Masliah, Eliezer; Winner, Beate; Wegner, Michael; Winkler, Jürgen (Molecular and Cellular Neuroscience, 2014)
Myelin loss is a widespread neuropathological hallmark of the atypical parkinsonian disorder multiple system atrophy (MSA). On a cellular level, MSA is characterized by alpha-synuclein (aSyn)-positive glial cytoplasmic inclusions (GCIs) within mature oligodendrocytes leading to demyelination as well as axonal and neuronal loss. Oligodendrocyte progenitor cells (OPCs) represent a proliferative cell population distributed throughout the adult mammalian central nervous system. During remyelination, OPCs are recruited to sites of demyelination, differentiate, and finally replace dysfunctional mature oligodendrocytes. However, comprehensive studies investigating OPCs and remyelination processes in MSA are lacking. In the present study, we therefore investigate the effect of human aSyn (h-aSyn) on early primary rat OPC maturation. Upon lentiviral transduction, h-aSyn expressing OPCs exhibit fewer and shorter primary processes at the initiation of differentiation. Until day 4 of a 6day differentiation paradigm, h-aSyn expressing OPCs further show a severely delayed maturation evidenced by reduced myelin gene expression and increased levels of the progenitor marker platelet derived growth factor receptor-alpha (PDGFR?). Matching these results, OPCs that take up extracellular recombinant h-aSyn exhibit a similar delayed differentiation. In both experimental setups however, myelin gene expression is restored at day 6 of differentiation paralleled by decreased intracellular h-aSyn levels indicating a reverse correlation of h-aSyn and the differentiation potential of OPCs. Taken together, these findings suggest a tight link between the intracellular level of h-aSyn and maturation capacity of primary OPCs.
EVALuna2:4696

Intracellular glycation of nuclear DNA, mitochondrial DNA, and cytosolic proteins during senescence-like growth arrest - Breyer, Viola; Becker, Cord-Michael; Pischetsrieder, Monika (DNA and Cell Biology, 2011)
To investigate the accumulation of intracellular advanced glycation end products (AGEs), a method was established for the simultaneous analysis of glycation products of cytosolic proteins, nuclear DNA, and mitochondrial DNA (mtDNA). Nuclear DNA, mtDNA, and cytosolic proteins were simultaneously isolated from one cell lysate by differential centrifugation and combined mechanical and chemical cell disruption methods. The major DNA-AGE N 2-carboxyethyl- 2′-deoxyguanosine (CEdG) was quantified in nuclear DNA and mtDNA by ELISA, whereas the protein-AGEs N-(carboxymethyl)lysine (CML) and N ε-(carboxyethyl)lysine (CEL) were determined by western blot. The method was used to analyze NIH3T3 fibroblasts. In untreated cells, CEdG levels of mtDNA (14.84 ± 3.07 pg CEdG/μg mtDNA) were significantly higher compared with nuclear DNA (4.40 ± 0.64 pg CEdG/μg DNA; p < 0.001). Then, fibroblasts were analyzed after 7 days of senescence-like growth arrest. In senescent fibroblasts, the CEdG content of nuclear DNA significantly increased by 25%. However, the CEdG level of mtDNA significantly decreased to 52%; in parallel, an increase in mitochondrial mass and mtDNA was observed. Senescence did not lead to general accumulation of protein-AGEs, but two protein bands at 32 and 34 kDa showed a significant increase in the CML/CEL modification rate (208%, p < 0.001; 196%, p = 0.0016) in senescent fibroblasts compared with control cells. © Copyright 2011, Mary Ann Liebert, Inc.
UnivIS-Import:2015-03-09:Pub.2011.nat.dchph.llmch.intrac

Intracellular localization map of human herpesvirus 8 proteins. - Sander, Gaby; Konrad, Andreas; Thurau, Mathias; Wies, Effi; Leubert, Rene; Kremmer, Elisabeth; Dinkel, Holger; Schulz, Thomas; Neipel, Frank; Stürzl, Michael (Journal of Virology, 2008)
Human herpesvirus 8 (HHV-8) is the etiological agent of Kaposi's sarcoma. We present a localization map of 85 HHV-8-encoded proteins in mammalian cells. Viral open reading frames were cloned with a Myc tag in expression plasmids, confirmed by full-length sequencing, and expressed in HeLa cells. Protein localizations were analyzed by immunofluorescence microscopy. Fifty-one percent of all proteins were localized in the cytoplasm, 22% were in the nucleus, and 27% were found in both compartments. Surprisingly, we detected viral FLIP (v-FLIP) in the nucleus and in the cytoplasm, whereas cellular FLIPs are generally localized exclusively in the cytoplasm. This suggested that v-FLIP may exert additional or alternative functions compared to cellular FLIPs. In addition, it has been shown recently that the K10 protein can bind to at least 15 different HHV-8 proteins. We noticed that K10 and only five of its 15 putative binding factors were localized in the nucleus when the proteins were expressed in HeLa cells individually. Interestingly, in coexpression experiments K10 colocalized with 87% (13 of 15) of its putative binding partners. Colocalization was induced by translocation of either K10 alone or both proteins. These results indicate active intracellular translocation processes in virus-infected cells. Specifically in this framework, the localization map may provide a useful reference to further elucidate the function of HHV-8-encoded genes in human diseases.

Investigation of the dynamics of the viral immediate-early protein 1 in different conformations and oligomerization states - Stump, Joachim; Sticht, Heinrich (Journal of Biomolecular Structure & Dynamics, 2016)
The viral immediate-early protein 1 (IE1) is crucial for efficient replication of cytomegalovirus (CMV). A recent crystal structure of the IE1 protein from rhesus CMV revealed that the protein exhibits a novel fold and crystallizes in two slightly different dimeric arrangements. Molecular dynamics simulations and energetic analyses performed in this study show that both dimers are stable and allowed us to identify a common set of five residues that appear particularly important for dimer formation. These residues are distributed over the entire dimer interface and do not form a typical hot spot for protein interactions. In addition, the dimer interface of IE1 proved to include a high portion of hydrophilic interactions pointing toward the transient nature of dimer formation. Characterization of monomeric and dimeric IE1 revealed three sequentially discontinuous dynamic domains that exhibit correlated motion within the domain and are simultaneously anti-correlated to the adjacent domains. The hinge motions observed between the dynamic domains increase the shape complementarity to the coiled-coil region of tripartite motif proteins, suggesting that the detected dynamics of IE1 might be physiologically important by enabling a better interaction with its cellular target molecules.
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Investigation of toxicity and mutagenicity of cold atmospheric argon plasma - Maisch, T.; Boßerhoff, Anja Katrin; Unger, P.; Heider, J.; Shimizu, T.; Zimmermann, J. L.; Morfill, G. E.; Landthaler, M.; Karrer, S. (ENVIRON MOL MUTAGEN, 2017)
Cold atmospheric argon plasma is recognized as a new contact free approach for the decrease of bacterial load on chronic wounds in patients. So far very limited data are available on its toxicity and mutagenicity on eukaryotic cells. Thus, the toxic/mutagenic potential of cold atmospheric argon plasma using the MicroPlaSter ?(®) , which has been used efficiently in humans treating chronic and acute wounds, was investigated using the XTT assay in keratinocytes and fibroblasts and the HGPRT (hypoxanthine guanine phosphoribosyl transferase) assay with V79 Chinese hamster cells. The tested clinical parameter of a 2 min cold atmospheric argon plasma treatment revealed no relevant toxicity on keratinocytes (viability: 76% ± 0.17%) and on fibroblasts (viability: 81.8 ± 0.10) after 72 hr as compared to the untreated controls. No mutagenicity was detected in the HGPRT assay with V79 cells even after repetitive CAP treatments of 2-10 min every 24 hr for up to 5 days. In contrast, UV-C irradiation of V79 cells, used as a positive control in the HGPRT test, led to DNA damage and mutagenic effects. Our findings indicate that cold atmospheric plasma using the MicroPlaSter ?(®) shows negligible effects on keratinocytes and fibroblasts but no mutagenic potential in the HGPRT assay, indicating a new contact free safe technology. Environ. Mol. Mutagen. 58:172-177, 2017. © 2017 Wiley Periodicals, Inc.
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In vitro and in vivo effects on neural crest stem cell differentiation by conditional activation of Runx1 short isoform and its effect on neuropathic pain behaviour. - Wegner, Michael; et al. (Upsala Journal of Medical Sciences, 2010)
Introduction. Runx1, a Runt domain transcription factor, controls the differentiation of nociceptors that express the neurotrophin receptor Ret, regulates the expression of many ion channels and receptors, and controls the lamina-specific innervation pattern of nociceptive afferents in the spinal cord. Moreover, mice lacking Runx1 exhibit specific defects in thermal and neuropathic pain. We investigated whether conditional activation of Runx1 short isoform (Runx1a), which lacks a transcription activation domain, influences differentiation of neural crest stem cells (NCSCs) in vitro and in vivo during development and whether postnatal Runx1a activation affects the sensitivity to neuropathic pain. Methods. We activated ectopic expression of Runx1a in cultured NCSCs using the Tet-ON gene regulatory system during the formation of neurospheres and analyzed the proportion of neurons and glial cells originating from NCSCs. In in vivo experiments we applied doxycycline (DOX) to pregnant mice (days 8-11), i.e. when NCSCs actively migrate, and examined the phenotype of offsprings. We also examined whether DOX-induced activation of Runx1a in adult mice affects their sensitivity to mechanical stimulation following a constriction injury of the sciatic nerve. Results. Ectopic Runx1a expression in cultured NCSCs resulted in predominantly glial differentiation. Offsprings in which Runx1a had been activated showed retarded growth and displayed megacolon, pigment defects, and dystrophic dorsal root ganglia. In the neuropathic pain model, the threshold for mechanical sensitivity was markedly increased following activation of Runx1a. Conclusion. These data suggest that Runx1a has a specific role in NCSC development and that modulation of Runx1a activity may reduce mechanical hypersensitivity associated with neuropathic pain.
UnivIS-Import:2015-03-09:Pub.2010.med.IB.LPCIPDBI.invitr
Keywords: Development; Gene regulation; Neuroglia; Pain; Sensory neuron; Transcription factor

In vivo imaging using fluorescent antibodies to tumor necrosis factor predicts therapeutic response in Crohn's disease - Atreya, Raja; Neumann, Helmut; Neufert, Clemens; Waldner, Maximilian; Billmeier, Ulrike; Zopf, Yurdagül; Willma, Marcus; App, Christine; Münster, Tino; Kessler, Hermann; Maas, Stefanie; Gebhardt, Bernd; et al. (Nature Medicine, 2014)
As antibodies to tumor necrosis factor (TNF) suppress immune responses in Crohn's disease by binding to membrane-bound TNF (mTNF), we created a fluorescent antibody for molecular mTNF imaging in this disease. Topical antibody administration in 25 patients with Crohn's disease led to detection of intestinal mTNF(+) immune cells during confocal laser endomicroscopy. Patients with high numbers of mTNF(+) cells showed significantly higher short-term response rates (92%) at week 12 upon subsequent anti-TNF therapy as compared to patients with low amounts of mTNF(+) cells (15%). This clinical response in the former patients was sustained over a follow-up period of 1 year and was associated with mucosal healing observed in follow-up endoscopy. These data indicate that molecular imaging with fluorescent antibodies has the potential to predict therapeutic responses to biological treatment and can be used for personalized medicine in Crohn's disease and autoimmune or inflammatory disorders.
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In vivo targeting of adult neural stem cells in the dentate gyrus by a split-cre approach - Beckervordersandforth, Ruth; Deshpande, Aditi; Schäffner, Iris; Huttner, Hagen; Lepier, Alexandra; Lie, Dieter Chichung; Goetz, Magdalena (Stem Cell Reports, 2014)
We describe the labeling of adult neural stem cells (aNSCs) in the mouse and human dentate gyrus (DG) by the combinatorial expression of glial fibrillary acidic protein (GFAP) and Prominin1, as revealed by immunohistochemistry. Split-Cre-based genetic fate mapping of these double-positive cells in the adult murine DG reveals their NSC identity, as they are self-renewing and contribute to neurogenesis over several months. Their progeny reacts to stimuli such as voluntary exercise with increased neurogenesis. Prominin1+/GFAP+ cells also exist in the adult human DG, the only region in the human brain for which adult neurogenesis has been consistently reported. Our data, together with previous evidence of such double-positive NSCs in the developing murine brain and in neurogenic regions of vertebrates with widespread neurogenesis, suggest that Prominin1- and GFAP-expressing cells are NSCs in a wide range of species in development and adulthood.
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Iso-alpha acids from hops (Humulus lupulus) inhibit hepatic steatosis, inflammation, and fibrosis - Mahli, Abdo; Koch, Andreas; Fresse, Kim; Schiergens, Tobias; Thasler, Wolfgang Erwin; Schoenberger, Christina; Bergheim, Ina; Boßerhoff, Anja Katrin; Hellerbrand, Claus (Laboratory Investigation, 2018)
Non-alcoholic fatty liver disease (NAFLD) is considered to be the hepatic manifestation of the metabolic syndrome. Iso-alpha acids (IAAs), hop-derived bitter compounds in beer, have been shown to beneficially affect different components of the metabolic syndrome such as insulin resistance and dyslipidemia. However, IAAs have not yet been studied in the context of chronic liver disease. Here we analyzed the effect of IAA on the pathogenesis of NAFLD. Once, we applied IAA to mice in combination with a NAFLD-inducing Western-type diet (WTD), and observed that IAA significantly inhibited WTD-induced body weight gain, glucose intolerance, and hepatic steatosis. Fitting to this, IAA dose-dependently inhibited cellular lipid accumulation in primary human hepatocytes (PHH) in vitro. Reduced expression of PPAR-gamma and key enzymes of lipid synthesis as well as increased expression of PPAR-alpha, indicative for increased lipid combustion, were identified as underlying mechanisms of reduced hepatocellular steatosis in vitro and in vivo. Analysis of hepatic HMOX1 expression indicated reduced oxidative stress in IAA-treated mice, which was paralleled by reduced activation of the JNK pathway and pro-inflammatory gene expression and immune cell infiltration. Furthermore, IAA reduced hepatic stellate cell (HSC) activation and pro-fibrogenic gene expression. Similarly, IAA also dose-dependently reduced oxidative stress and JNK activation in steatotic PHH, inhibited HSC activation, and reduced proliferation and pro-fibrogenic gene expression in already activated HSC in vitro. In conclusion, IAAs inhibit different pathophysiological steps of disease progression in NAFLD. Together with previous studies, which demonstrated the safety of even long-term application of IAA in humans, our data suggest IAA as promising therapeutic agent for the prevention and treatment of (non)alcoholic (fatty) liver disease.
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Kdm6b and Pmepa1 as Targets of Bioelectrically and Behaviorally Induced Activin A Signaling - Link, Andrea; Kurinna, Svitlana; Havlicek, Steven; Lehnert, Sandra; Reichel, Martin; Kornhuber, Johannes; Winner, Beate; Huth, Tobias; Zheng, Fang; Werner, Sabine; Alzheimer, Christian (Molecular Neurobiology, 2016)
The transforming growth factor-? (TGF-?) family member activin A exerts multiple neurotrophic and protective effects in the brain. Activin also modulates cognitive functions and affective behavior and is a presumed target of antidepressant therapy. Despite its important role in the injured and intact brain, the mechanisms underlying activin effects in the CNS are still largely unknown. Our goal was to identify the first target genes of activin signaling in the hippocampus in vivo. Electroconvulsive seizures, a rodent model of electroconvulsive therapy in humans, were applied to C57BL/6J mice to elicit a strong increase in activin A signaling. Chromatin immunoprecipitation experiments with hippocampal lysates subsequently revealed that binding of SMAD2/3, the intracellular effectors of activin signaling, was significantly enriched at the Pmepa1 gene, which encodes a negative feedback regulator of TGF-? signaling in cancer cells, and at the Kdm6b gene, which encodes an epigenetic regulator promoting transcriptional plasticity. Underlining the significance of these findings, activin treatment also induced PMEPA1 and KDM6B expression in human forebrain neurons generated from embryonic stem cells suggesting interspecies conservation of activin effects in mammalian neurons. Importantly, physiological stimuli such as provided by environmental enrichment proved already sufficient to engender a rapid and significant induction of activin signaling concomitant with an upregulation of Pmepa1 and Kdm6b expression. Taken together, our study identified the first target genes of activin signaling in the brain. With the induction of Kdm6b expression, activin is likely to gain impact on a presumed epigenetic regulator of activity-dependent neuronal plasticity.
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KLB is associated with alcohol drinking, and its gene product β-Klotho is necessary for FGF21 regulation of alcohol preference - Schumann, Gunter; Liu, Chunyu; O'Reilly, Paul; Gao, He; Song, Parkyong; Xu, Bing; Ruggeri, Barbara; Amin, Najaf; Jia, Tianye; Preis, Sarah; Lepe, Marcelo Segura; Akira, Shizuo; et al. (Proceedings of the National Academy of Sciences of the United States of America, 2016)
Excessive alcohol consumption is a major public health problem worldwide. Although drinking habits are known to be inherited, few genes have been identified that are robustly linked to alcohol drinking. We conducted a genome-wide association metaanalysis and replication study among >105,000 individuals of European ancestry and identified ?-Klotho (KLB) as a locus associated with alcohol consumption (rs11940694; P = 9.2 × 10(-12)). ?-Klotho is an obligate coreceptor for the hormone FGF21, which is secreted from the liver and implicated in macronutrient preference in humans. We show that brain-specific ?-Klotho KO mice have an increased alcohol preference and that FGF21 inhibits alcohol drinking by acting on the brain. These data suggest that a liver-brain endocrine axis may play an important role in the regulation of alcohol drinking behavior and provide a unique pharmacologic target for reducing alcohol consumption.
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KLF9 and KLF13 transcription factors boost myelin gene expression in oligodendrocytes as partners of SOX10 and MYRF - Bernhardt, Celine; Sock, Elisabeth; Fröb, Franziska; Hillgärtner, Simone; Nemer, Mona; Wegner, Michael (Nucleic Acids Research, 2022)
Differentiated oligodendrocytes produce myelin and thereby ensure rapid nerve impulse conduction and efficient information processing in the vertebrate central nervous system. The Kruppel-like transcription factor KLF9 enhances oligodendrocyte differentiation in culture, but appears dispensable in vivo. Its mode of action and role within the oligodendroglial gene regulatory network are unclear. Here we show that KLF9 shares its expression in differentiating oligodendrocytes with the closely related KLF13 protein. Both KLF9 and KLF13 bind to regulatory regions of genes that are important for oligodendrocyte differentiation and equally recognized by the central differentiation promoting transcription factors SOX10 and MYRF. KLF9 and KLF13 physically interact and synergistically activate oligodendrocyte-specific regulatory regions with SOX10 and MYRF. Similar to KLF9, KLF13 promotes differentiation and myelination in primary oligodendroglial cultures. Oligodendrocyte differentiation is also altered in KLF13-deficient mice as demonstrated by a transiently reduced myelin gene expression during the first postnatal week. Considering mouse phenotypes, the similarities in expression pattern and genomic binding and the behaviour in functional assays, KLF9 and KLF13 are important and largely redundant components of the gene regulatory network in charge of oligodendrocyte differentiation and myelination.
CRIS-Team WoS Importer:2022-11-11

Knockdown of Lamin B1 and the Corresponding Lamin B Receptor Leads to Changes in Heterochromatin State and Senescence Induction in Malignant Melanoma - Lämmerhirt, Lisa; Kappelmann-Fenzl, Melanie; Fischer, Stefan; Pommer, Michaela; Zimmermann, Tom; Kluge, Viola; Matthies, Alexander Oliver; Kuphal, Silke; Boßerhoff, Anja Katrin (Cells, 2022)
Modifications in nuclear structures of cells are implicated in several diseases including cancer. They result in changes in nuclear activity, structural dynamics and cell signalling. However, the role of the nuclear lamina and related proteins in malignant melanoma is still unknown. Its molecular characterisation might lead to a deeper understanding and the development of new therapy approaches. In this study, we analysed the functional effects of dysregulated nuclear lamin B1 (LMNB1) and its nuclear receptor (LBR). According to their cellular localisation and function, we revealed that these genes are crucially involved in nuclear processes like chromatin organisation. RNA sequencing and differential gene expression analysis after knockdown of LMNB1 and LBR revealed their implication in important cellular processes driving ER stress leading to senescence and changes in chromatin state, which were also experimentally validated. We determined that melanoma cells need both molecules independently to prevent senescence. Hence, downregulation of both molecules in a BRAFV600E melanocytic senescence model as well as in etoposide-treated melanoma cells indicates both as potential senescence markers in melanoma. Our findings suggest that LMNB1 and LBR influence senescence and affect nuclear processes like chromatin condensation and thus are functionally relevant for melanoma progression.
CRIS-Team Scopus Importer:2022-08-05
Keywords: chromatin state; heterochromatin foci; LBR; LMNB1; melanoma; nuclear lamina; senescence

L1cam acts as a modifier gene during enteric nervous system development. - Wegner, Michael; et al. (Neurobiology of Disease, 2010)
The enteric nervous system is derived from neural crest cells that migrate from the caudal hindbrain and colonise the gut. Failure of neural crest cells to fully colonise the gut results in an "aganglionic zone" that lacks a functional enteric nervous system over a variable length of the distal bowel, a condition in human infants known as Hirschsprung's disease. The variability observed in the penetrance and severity of Hirschsprung's disease suggests a role for modifier genes. Clinical studies have identified a population of Hirschsprung's patients with mutations in L1CAM that also have a common polymorphism in RET, suggesting a possible interaction between L1CAM and RET. Therefore, we examined whether L1cam could interact with Ret, its ligand Gdnf, and a known transcriptional activator of Ret, Sox10. Using a two-locus complementation approach, we show that loss of L1cam in conjunction with a heterozygous loss of Ret or Gdnf did not result in aganglionosis. However, L1cam did interact with Sox10 to significantly increase the incidence of aganglionosis. We show that an interaction between L1cam and Sox10 significantly perturbs neural crest migration within the developing gut, and that neural crest cells undergo excessive cell death prior to gut entry. Finally, we show that Sox10 can regulate the expression of L1cam. Thus, L1cam can act as a modifier gene for the HSCR associated gene, Sox10, and is likely to play a role in the etiology of Hirschsprung's disease. © 2010 Elsevier Inc.
UnivIS-Import:2015-03-09:Pub.2010.med.IB.LPCIPDBI.l1cama
Keywords: Cell migration; Development; Enteric nervous system; Hirschsprung's disease; Neural crest

Lack of Desmin in Mice Causes Structural and Functional Disorders of Neuromuscular Junctions - Eiber, Nane; Fröb, Franziska; Schowalter, Mirjam; Thiel, Christian; Clemen, Christoph S.; Schröder, Rolf; Hashemolhosseini, Said (Frontiers in Molecular Neuroscience, 2020)
Desmin, the major intermediate filament (IF) protein in muscle cells, interlinks neighboring myofibrils and connects the whole myofibrillar apparatus to myonuclei, mitochondria, and the sarcolemma. However, desmin is also known to be enriched at postsynaptic membranes of neuromuscular junctions (NMJs). The pivotal role of the desmin IF cytoskeletal network is underscored by the fact that over 120 mutations of the human DES gene cause hereditary and sporadic myopathies and cardiomyopathies. A subgroup of human desminopathies comprises autosomal recessive cases resulting in the complete abolition of desmin protein. In these patients, who display a more severe phenotype than the autosomal dominant cases, it has been reported that some individuals also suffer from a myasthenic syndrome in addition to the classical occurrence of myopathy and cardiomyopathy. Since further studies on the NMJ pathology are hampered by the lack of available human striated muscle biopsy specimens, we exploited homozygous desmin knock-out mice which closely mirror the striated muscle pathology of human patients lacking desmin protein. Here, we report on the impact of the lack of desmin on the structure and function of NMJs and the transcription of genes coding for postsynaptic proteins. Desmin knock-out mice display a fragmentation of NMJs in soleus, but not in the extensor digitorum longus muscle. Moreover, soleus muscle fibers show larger NMJs. Further, transcription levels of acetylcholine receptor (AChR) genes are increased in muscles from desmin knock-out mice, especially of the AChR gamma subunit, which is known as a marker of muscle fiber regeneration. Electrophysiological recordings depicted a pathological decrement of nerve-dependent endplate potentials and an increased rise time of the nerve-independent miniature endplate potentials. The latter appears related to the fragmentation of NMJs in desmin knockout mice. Our study highlights the essential role of desmin for the structural and functional integrity of mammalian NMJs.
CRIS-Team WoS Importer:2020-11-27

Lack of Wdr36 leads to preimplantation embryonic lethality in mice and delays the formation of small subunit ribosomal RNA in human cells in vitro. - Wegner, Michael; et al. (Human Molecular Genetics, 2011)
Mutations in WD repeat domain 36 gene (WDR36) play a causative role in some forms of primary open-angle glaucoma, a leading cause of blindness worldwide. WDR36 is characterized by the presence of multiple WD40 repeats and shows homology to Utp21, an essential protein component of the yeast small subunit (SSU) processome required for maturation of 18S rRNA. To clarify the functional role of WDR36 in the mammalian organism, we generated and investigated mutant mice with a targeted deletion of Wdr36. In parallel experiments, we used RNA interference to deplete WDR36 mRNA in mouse embryos and cultured human trabecular meshwork (HTM-N) cells. Deletion of Wdr36 in the mouse caused preimplantation embryonic lethality, and essentially similar effects were observed when WDR36 mRNA was depleted in mouse embryos by RNA interference. Depletion of WDR36 mRNA in HTM-N cells caused apoptotic cell death and upregulation of mRNA for BAX, TP53 and CDKN1A. By immunocytochemistry, staining for WDR36 was observed in the nucleolus of cells, which co-localized with that of nucleolar proteins such as nucleophosmin and PWP2. In addition, recombinant and epitope-tagged WDR36 localized to the nucleolus of HTM-N cells. By northern blot analysis, a substantial decrease in 21S rRNA, the precursor of 18S rRNA, was observed following knockdown of WDR36. In addition, metabolic-labeling experiments consistently showed a delay of 18S rRNA maturation in WDR36-depleted cells. Our results provide evidence that WDR36 is an essential protein in mammalian cells which is involved in the nucleolar processing of SSU 18S rRNA. © The Author 2010. Published by Oxford University Press. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2011.med.IB.LPCIPDBI.lackof

LAP proteins are localized at the post-synaptic membrane of neuromuscular junctions and appear to modulate synaptic morphology and transmission - Kravic, Bojana; Huraskin, Danyil; Frick, Alexander; Jung, Jasmin; Redai, Veronika; Palmisano, Ralf; Marchetto, Sylvie; Borg, Jean-Paul; Mei, Lin; Hashemolhosseini, Said (Journal of Neurochemistry, 2016)
Erbin, Lano, Scribble, and Densin-180 belong to LAP (leucine-rich repeats and PDZ domain) adaptor proteins involved in cell signaling pathways. Previously, we identified Erbin, Lano, and Scribble, but not Densin-180, in muscle cells, where they are involved in regulating the aggregation of nicotinic acetylcholine receptors in vitro. Here, we analyzed their cellular localization at the neuromuscular junction (NMJ) in skeletal muscles of mice. Erbin, Lano, and Scribble were significantly accumulated at NMJs and localized in different synaptic cells. Moreover, we used mouse mutants to analyze the role of Erbin at the NMJ. We used two Erbin mutant mouse strains that either completely lack Erbin protein (Erbin(null/null) ) or express a truncated Erbin mutant where the carboxy-terminal PDZ domain is replaced by ?-galactosidase (Erbin(?C/?C) ) thereby abolishing its interaction with ErbB receptor tyrosine kinases. Neither the lack of the PDZ domain of Erbin, nor its complete absence interfered with the general localization of LAP proteins at NMJs, but Lano and Scribble transcript levels were up-regulated in homozygous Erbin-null muscles. Furthermore, grip strength was reduced and neural transmission impaired in homozygous aged Erbin-null but not Erbin-?C mice. Erbin-null skeletal muscles did not reveal any conspicuous impairment of the muscle fiber. Localization of other NMJ marker proteins was not affected either. Quantitative 3D morphometry showed that NMJs of Erbin-null muscles were significantly smaller and fragmented in the soleus. We speculate that Erbin, Lano, and Scribble act at the post-synaptic membrane of NMJs in a concerted fashion to regulate nicotinic acetylcholine receptors cluster morphology and neural transmission. Cover Image for this issue: doi: 10.1111/jnc.13340.
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Late-Onset Aspergillus Fumigatus Infection of an Aortic Stent Graft in an Immunocompetent Patient - Ballazhi, Fatos; Weyand, Michael; Lang, Werner; Schoerner, Christoph; Seitz, Tatjana (Thoracic and Cardiovascular Surgeon Reports, 2015)
Aspergillus fumigatus as a clinical entity is difficult to diagnose. We present a case, which could facilitate diagnosis and management of the aforementioned disease. A 60-year-old man with stent graft implantation in the descending aorta (6 years ago) presented with fever, night sweats, and weight loss over 5 months. Leukocytosis and elevated C-reactive protein were constantly spiking. Blood cultures were negative. Notably, the serum immunoglobulin E (IgE) level was strongly elevated (> 1,000 U/mL). Anamnestically, the patient suffered from a mild form of atopic dermatitis and bronchial asthma. The pulmonary status showed no abnormalities in the computed tomography image. Nonetheless, a chest scan revealed a suspected abscess around the stent graft of the descending aorta. Extra-anatomic ascending to descending aortic bypass (Gelsoft 22 mm, Vascutek, Juchinnan, Scotland, United Kingdom) was performed. Intraoperative samples revealed A. fumigatus. These findings were confirmed by polymerase chain reaction analysis. Infection by A. fumigatus represents a diagnostic challenge because blood cultures are usually negative, but expeditious treatment is required to prevent occurrence of irreversible complications. A late graft infection, possibly caused by A. fumigatus should be suspected in patients with implanted grafts, who suffer from unexplained, blood culture-negative fever that does not respond to antibiotics and who have a history of dermatitis or bronchial asthma with elevated IgE antibodies.
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Learning from Embryogenesis-A Comparative Expression Analysis in Melanoblast Differentiation and Tumorigenesis Reveals miRNAs Driving Melanoma Development - Linck-Paulus, Lisa; Lämmerhirt, Lisa; Voeller, Daniel; Meyer, Katharina; Engelmann, Julia C.; Spang, Rainer; Eichner, Norbert; Meister, Gunter; Kuphal, Silke; Boßerhoff, Anja Katrin (Journal of Clinical Medicine, 2021)
Malignant melanoma is one of the most dangerous tumor types due to its high metastasis rates and a steadily increasing incidence. During tumorigenesis, the molecular processes of embryonic development, exemplified by epithelial-mesenchymal transition (EMT), are often reactivated. For melanoma development, the exact molecular differences between melanoblasts, melanocytes, and melanoma cells are not completely understood. In this study, we aimed to identify microRNAs (miRNAs) that promote melanoma tumorigenesis and progression, based on an in vitro model of normal human epidermal melanocyte (NHEM) de-differentiation into melanoblast-like cells (MBrCs). Using miRNA-sequencing and differential expression analysis, we demonstrated in this study that a majority of miRNAs have an almost equal expression level in NHEMs and MBrCs but are significantly differentially regulated in primary tumor- and metastasis-derived melanoma cell lines. Further, a target gene analysis of strongly regulated but functionally unknown miRNAs yielded the implication of those miRNAs in many important cellular pathways driving malignancy. We hypothesize that many of the miRNAs discovered in our study are key drivers of melanoma development as they account for the tumorigenic potential that differentiates melanoma cells from proliferating or migrating embryonic cells.
CRIS-Team WoS Importer:2021-06-25

Length of the TM3-4 loop of the glycine receptor modulates receptor desensitization - Langlhofer, G.; Janzen, D.; Meiselbach, Heike; Villmann, C. (Neuroscience Letters, 2015)
Recent studies on the molecular determinants important for glycine receptor biogenesis and function mechanisms indicate an important role of basic residues within the intracellular loop between transmembrane domains (TM) 3 and 4. We investigate the role of loop length and loop exchange in combination with the presence or absence of basic stretches (318)RRKRR and (385)KKIDK of the human glycine receptor ?1 using expression in transfected cell lines. Exchanges of the large intracellular loop between members of the Cys-loop receptor family have been shown to keep functionality of the host receptor. Here, constructs were generated with deletion of the intracellular loop of the glycine receptor ?1, insertion of the loop from the prokaryotic Cys-loop receptor of Gloeobacter violaceus both with and without leaving the basic stretches at the N-terminal and C-terminal part of the intracellular domain. All receptor constructs were expressed at the cell surface with the significantly lowest expression of the construct with a deletion of the glycine receptor ?1 TM3-4 loop, except the two basic stretches adjoined. Functionality of the inhibitory glycine receptor chimeras was demonstrated with whole cell recordings from transfected cells. Chimeras lacking the basic stretches result in non-functionality. An analysis of receptor desensitization demonstrated that close proximity of both basic stretches resulted in large fractions of desensitizing currents. We conclude that the TM3-4 loop length is critical for glycine receptor ?1 desensitization and a direct neighborhood of both basic stretches changes receptor properties from non-desensitizing to desensitizing.
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LHX2 haploinsufficiency causes a variable neurodevelopmental disorder - Schmid, Cosima M.; Gregor, Anne; Costain, Gregory; Morel, Chantal F.; Massingham, Lauren; Schwab, Jennifer; Quélin, Chloé; Faoucher, Marie; Kaplan, Julie; Procopio, Rebecca; Saunders, Carol J.; Cohen, Ana S.A.; et al. (Genetics in Medicine, 2023)
Purpose: LHX2 encodes the LIM homeobox 2 transcription factor (LHX2), which is highly expressed in brain and well conserved across species, but it has not been clearly linked to neurodevelopmental disorders (NDDs) to date. Methods: Through international collaboration, we identified 19 individuals from 18 families with variable neurodevelopmental phenotypes, carrying a small chromosomal deletion, likely gene-disrupting or missense variants in LHX2. Functional consequences of missense variants were investigated in cellular systems. Results: Affected individuals presented with developmental and/or behavioral abnormalities, autism spectrum disorder, variable intellectual disability, and microcephaly. We observed nucleolar accumulation for 2 missense variants located within the DNA-binding HOX domain, impaired interaction with co-factor LDB1 for another variant located in the protein-protein interaction–mediating LIM domain, and impaired transcriptional activation by luciferase assay for 4 missense variants. Conclusion: We implicate LHX2 haploinsufficiency by deletion and likely gene-disrupting variants as causative for a variable NDD. Our findings suggest a loss-of-function mechanism also for likely pathogenic LHX2 missense variants. Together, our observations underscore the importance of LHX2 in the nervous system and for variable neurodevelopmental phenotypes.
CRIS-Team Scopus Importer:2023-07-07
Keywords: ASD; Intellectual disability; LHX2; Microcephaly; NDD; Neurodevelopmental disorder

Lidocaine metabolites inhibit glycine transporter 1: a novel mechanism for the analgesic action of systemic lidocaine? - Werdehausen, Robert; Kremer, David; Brandenburger, Timo; Schloesser, Lukas; Jadasz, Janusz; Kuery, Patrick; Bauer, Inge; Aragon, Carmen; Eulenburg, Volker; Hermanns, Henning (Anesthesiology, 2012)
Lidocaine exerts antinociceptive effects when applied systemically. The mechanisms are not fully understood but glycinergic mechanisms might be involved. The synaptic glycine concentration is controlled by glycine transporters. Whereas neurons express two types of glycine transporters, astrocytes specifically express glycine transporter 1 (GlyT1). This study focuses on effects of lidocaine and its major metabolites on GlyT1 function.The effects of lidocaine and its metabolites monoethylglycinexylidide (MEGX), glycinexylidide, and N-ethylglycine on GlyT1 function were investigated in uptake experiments with [¹?C]-labeled glycine in primary rat astrocytes. Furthermore, the effect of lidocaine and its metabolites on glycine-induced currents were investigated in GlyT1-expressing Xenopus laevis oocytes.Lidocaine reduced glycine uptake only at toxic concentrations. The metabolites MEGX, glycinexylidide, and N-ethylglycine, however, significantly reduced glycine uptake (P < 0.05). Inhibition of glycine uptake by a combination of lidocaine with its metabolites at a clinically relevant concentration was diminished with increasing extracellular glycine concentrations. Detailed analysis revealed that MEGX inhibits GlyT1 function (P < 0.05), whereas N-ethylglycine was identified as an alternative GlyT1 substrate (EC?? = 55 ?M).Although lidocaine does not function directly on GlyT1, its metabolites MEGX and N-ethylglycine [corrected] were shown to inhibit GlyT1-mediated glycine uptake by at least two different mechanisms. Whereas N-ethylglycine [corrected] was demonstrated to be an alternative GlyT1 substrate, MEGX was shown to inhibit GlyT1 activity in both primary astrocytes and in GlyT1-expressing Xenopuslaevis oocytes at clinically relevant concentrations. These findings provide new insights into the possible mechanisms for the antinociceptive effect of systemic lidocaine.
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Lineage-reprogramming of pericyte-derived cells of the adult human brain into induced neurons - Karow, Marisa; Schichor, Christian; Beckervordersandforth, Ruth; Berninger, Benedikt (Journal of Visualized Experiments, 2014)
Direct lineage-reprogramming of non-neuronal cells into induced neurons (iNs) may provide insights into the molecular mechanisms underlying neurogenesis and enable new strategies for in vitro modeling or repairing the diseased brain. Identifying brain-resident non-neuronal cell types amenable to direct conversion into iNs might allow for launching such an approach in situ, i.e. within the damaged brain tissue. Here we describe a protocol developed in the attempt of identifying cells derived from the adult human brain that fulfill this premise. This protocol involves: (1) the culturing of human cells from the cerebral cortex obtained from adult human brain biopsies; (2) the in vitro expansion (approximately requiring 2-4 weeks) and characterization of the culture by immunocytochemistry and flow cytometry; (3) the enrichment by fluorescence-activated cell sorting (FACS) using anti-PDGF receptor-? and anti-CD146 antibodies; (4) the retrovirus-mediated transduction with the neurogenic transcription factors sox2 and ascl1; (5) and finally the characterization of the resultant pericyte-derived induced neurons (PdiNs) by immunocytochemistry (14 days to 8 weeks following retroviral transduction). At this stage, iNs can be probed for their electrical properties by patch-clamp recording. This protocol provides a highly reproducible procedure for the in vitro lineage conversion of brain-resident pericytes into functional human iNs.
EVALuna2:26324

Linking the Neuropsychiatric Disease Gene TCF4 to Neuronal Activity-Dependent Regulatory Networks - Wittmann, Marie-Theres; Häberle, Benjamin (The Journal of Neuroscience, 2018)
EVALuna2:34134

Lipid Accumulation in Host Cells Promotes SARS-CoV-2 Replication - Seitz, Tatjana; Setz, Christian; Rauch, Pia; Schubert, Ulrich; Hellerbrand, Claus (Viruses, 2023)
Coronavirus disease-19 (COVID-19) is still affecting the lives of people around the globe and remains a major public health threat. Lipid levels in the host cells have been shown to promote SARS-CoV-2 replication, and since the start of COVID-19 pandemic, several studies have linked obesity and other components of the metabolic syndrome with severity of illness, as well as mortality in patients with COVID-19. The aim of this study was to obtain insights into the pathophysiological mechanisms of these associations. First, we established an in vitro model simulating high fatty acid levels and showed that this situation induced the uptake of fatty acids and triglyceride accumulation in human Calu-3 lung cells. Importantly, we found that lipid accumulation significantly enhanced the replication of SARS-CoV-2 Wuhan type or the variant of concern, Delta, in Calu-3 cells. In summary, these findings indicate that hyperlipidemia as found in patients with obesity promotes viral replication and herewith the disease course of COVID-19.
CRIS-Team WoS Importer:2023-05-26

Localization of group II and III metabotropic glutamate receptors at pre- and postsynaptic sites of inner hair cell ribbon synapses - Klotz, Lisa; Wendler, Olaf; Frischknecht, Renato; Shigemoto, Ryuichi; Schulze, Holger; Enz, Ralf (The FASEB Journal, 2019)
Glutamate is the major excitatory neurotransmitter in the CNS binding to a variety of glutamate receptors. Metabotropic glutamate receptors (mGluR1 to mGluR8) can act excitatory or inhibitory, depending on associated signal cascades. Expression and localization of inhibitory acting mGluRs at inner hair cells (IHCs) in the cochlea are largely unknown. Here, we analyzed expression of mGluR2, mGluR3, mGluR4, mGluR6, mGluR7, and mGluR8 and investigated their localization with respect to the presynaptic ribbon of IHC synapses. We detected transcripts for mGluR2, mGluR3, and mGluR4 as well as for mGluR7a, mGluR7b, mGluR8a, and mGluR8b splice variants. Using receptor-specific antibodies in cochlear wholemounts, we found expression of mGluR2, mGluR4, and mGluR8b close to presynaptic ribbons. Super resolution and confocal microscopy in combination with 3-dimensional reconstructions indicated a postsynaptic localization of mGluR2 that overlaps with postsynaptic density protein 95 on dendrites of afferent type I spiral ganglion neurons. In contrast, mGluR4 and mGluR8b were expressed at the presynapse close to IHC ribbons. In summary, we localized in detail 3 mGluR types at IHC ribbon synapses, providing a fundament for new therapeutical strategies that could protect the cochlea against noxious stimuli and excitotoxicity.-Klotz, L., Wendler, O., Frischknecht, R., Shigemoto, R., Schulze, H., Enz, R. Localization of group II and III metabotropic glutamate receptors at pre- and postsynaptic sites of inner hair cell ribbon synapses.
CRIS-Team Scopus Importer:2019-12-17
Keywords: cochlea; IHC; mGlu receptor; mGluR

Local molecular properties and their use in predicting reactivity - Ehresmann, Bernd; Martin, Bodo; Horn, Anselm; Clark, Timothy (Journal of Molecular Modeling, 2003)
Expressions for the local electron affinity, electronegativity and hardness are derived in analogy to the local ionization energy introduced by Sjoberg, Murray and Politzer. The local polarizability is also defined based on an additive atomic orbital polarizability model that uses Rivail's variational technique. The characteristics of these local properties at molecular surfaces and their relevance to electrophilic aromatic substitution, to S(N)2 reactivity and to the nucleophilicity of enolate ions are discussed.
Keywords: surface properties; AM1; local ionization energy; local electron affinity; local hardness

Long-term application of glycine transporter inhibitors acts antineuropathic and modulates spinal N-methyl-D-aspartate receptor subunit NR-1 expression in rats - Barthel, Franziska; Urban, Andrea; Schlösser, Lukas; Eulenburg, Volker; Werdehausen, Robert; Brandenburger, Timo; Aragon, Carmen; Bauer, Inge; Hermanns, Henning (Anesthesiology, 2014)
Dysfunction of spinal glycinergic neurotransmission is a major pathogenetic factor in neuropathic pain. The synaptic glycine concentration is controlled by the two glycine transporters (GlyT) 1 and 2. GlyT inhibitors act antinociceptive in various animal pain models when applied as bolus. Yet, in some studies, severe neuromotor side effects were reported. The aim of the current study was to elucidate whether continuous inhibition of GlyT ameliorates neuropathic pain without side effects and whether protein expression of GlyT1, GlyT2, or N-methyl-D-aspartate receptor subunit NR-1 in the spinal cord is affected.In the chronic constriction injury model of neuropathic pain, male Wistar rats received specific GlyT1 and GlyT2 inhibitors (ALX5407 and ALX1393; Sigma-Aldrich, St. Louis, MO) or vehicle for 14 days via subcutaneous osmotic infusion pumps (n = 6). Mechanical allodynia and thermal hyperalgesia were assessed before, after chronic constriction injury, and every 2 days during substance application. At the end of behavioral assessment, the expression of GlyT1, GlyT2, and NR-1 in the spinal cord was determined by Western blot analysis.Both ALX5407 and ALX1393 ameliorated thermal hyperalgesia and mechanical allodynia in a time- and dose-dependent manner. Respiratory or neuromotor side effects were not observed. NR-1 expression in the ipsilateral spinal cord was significantly reduced by ALX5407, but not by ALX1393. The expression of GlyT1 and GlyT2 remained unchanged.Continuous systemic inhibition of GlyT significantly ameliorates neuropathic pain in rats. Thus, GlyT represent promising targets in pain research. Modulation of N-methyl-D-aspartate receptor expression might represent a novel mechanism for the antinociceptive action of GyT1 inhibitors.
EVALuna2:4702

Loss of CYLD accelerates melanoma development and progression in the Tg(Grm1) melanoma mouse model - de Jel, Miriam Martha; Schott, Mandy; Lamm, Susanne; Neuhuber, Winfried; Kuphal, Silke; Boßerhoff, Anja Katrin (Oncogenesis, 2019)
The deubiquitinase cylindromatosis (CYLD) is a well-known tumor suppressor, found to be down regulated in many cancer types including breast cancer, colon carcinoma and malignant melanoma. CYLD is suppressed in human melanoma cells by the transcriptional repressor SNAIL1 leading to an increase of their proliferative, invasive and migratory potential. To gain additional insights into the distinct function of this tumor suppressor gene a new mouse model Tg(Grm1)Cyld−/− was generated. Herewith, we demonstrate that Cyld-deficiency leads to earlier melanoma onset and accelerated tumor growth and metastasis in the GRM1 melanoma mouse model. First, RNA sequencing data revealed a potential role of CYLD in the regulation of genes involved in proliferation, migration and angiogenesis. Experiments using cell lines generated from both primary and metastatic melanoma tissue of Tg(Grm1) Cyld−/− and Tg(Grm1) Cyld+/+ mice confirmed that loss of CYLD enhances the proliferative and migratory potential, as well as the clonogenicity in vitro. Moreover, we could show that Cyld-knockout leads to increased vasculogenic mimicry and enhanced (lymph-) angiogenesis shown by tube formation assays, immunohistochemistry and mRNA expression analyses. In summary, our findings reveal new functional aspects of CYLD in the process of (lymph-) angiogenesis and demonstrate its importance in the early process of melanoma progression.
CRIS-Team Scopus Importer:2019-10-18

Loss of CYLD promotes melanoma progression - de Jel, Miriam Martha; Schiffner, S.; Kuphal, Silke; Boßerhoff, Anja Katrin (2016)
EVALuna2:4737

Loss of DNA-dependent dimerization of the transcription factor SOX9 as a cause for campomelic dysplasia - Sock, Elisabeth; Wegner, Michael; et al. (Human Molecular Genetics, 2003)
Campomelic dysplasia (CD) is a semilethal osteochondrodysplasia, characterized by skeletal anomalies that include bending of the long bones, and by XY sex reversal. CD results from haploinsufficiency for the transcription factor SOX9, a key regulator at various steps of cartilage differentiation and of early testis development. Two functional domains are so far recognized for SOX9, a high-mobility group (HMG) DNA-binding domain and a C-terminal transactivation domain. We present two CD patients with de novo mutations in a conserved region preceding the HMG domain. A long-term survivor with the acampomelic form of CD has an A76E amino acid substitution, while a severely affected CD patient had an in-frame deletion of amino acid residues 66-75. The conserved domain has been shown to function in the related transcription factor SOX10 as a DNA-dependent dimerization domain. We show that, like SOX10, SOX9 also binds cooperatively as a dimer to response elements in regulatory regions of some target genes such as the cartilage genes Col11a2 and CD-Rap. Dimerization and the resulting capacity to activate promoters via dimeric binding sites is lost in both mutant SOX9 proteins while other features involved in SOX9 function remained unaltered. These findings establish the dimerization domain as the third domain essential for SOX9 function during chondrogenesis.
UnivIS-Import:2015-03-09:Pub.2003.med.IB.LPCIPDBI.lossof

Loss-of-function and missense variants in NSD2 cause decreased methylation activity and are associated with a distinct developmental phenotype - Zanoni, Paolo; Steindl, Katharina; Sengupta, Deepanwita; Joset, Pascal; Bahr, Angela; Sticht, Heinrich; Lang-Muritano, Mariarosaria; Van Ravenswaaij-Arts, Conny M. A.; Shinawi, Marwan; Andrews, Marisa; Attie-Bitach, Tania; Maystadt, Isabelle; et al. (Genetics in Medicine, 2021)
Purpose: Despite a few recent reports of patients harboring truncating variants in NSD2, a gene considered critical for the Wolf–Hirschhorn syndrome (WHS) phenotype, the clinical spectrum associated with NSD2 pathogenic variants remains poorly understood. Methods: We collected a comprehensive series of 18 unpublished patients carrying heterozygous missense, elongating, or truncating NSD2 variants; compared their clinical data to the typical WHS phenotype after pooling them with ten previously described patients; and assessed the underlying molecular mechanism by structural modeling and measuring methylation activity in vitro. Results: The core NSD2-associated phenotype includes mostly mild developmental delay, prenatal-onset growth retardation, low body mass index, and characteristic facial features distinct from WHS. Patients carrying missense variants were significantly taller and had more frequent behavioral/psychological issues compared with those harboring truncating variants. Structural in silico modeling suggested interference with NSD2’s folding and function for all missense variants in known structures. In vitro testing showed reduced methylation activity and failure to reconstitute H3K36me2 in NSD2 knockout cells for most missense variants. Conclusion: NSD2 loss-of-function variants lead to a distinct, rather mild phenotype partially overlapping with WHS. To avoid confusion for patients, NSD2 deficiency may be named Rauch–Steindl syndrome after the delineators of this phenotype.
CRIS-Team Scopus Importer:2021-05-21

Loss of function of SVBP leads to autosomal recessive intellectual disability, microcephaly, ataxia, and hypotonia - Iqbal, Zafar; Tawamie, Hasan; Ba, Wei; Reis, André; Halak, Bassam Al; Sticht, Heinrich; Uebe, Steffen; Kasri, Nael Nadif; Riazuddin, Sheikh; van Bokhoven, Hans; Abou Jamra, Rami (Genetics in Medicine, 2019)
Purpose: Identifying and characterizing novel causes of autosomal recessive intellectual disability based on systematic clinical and genetic evaluation, followed by functional experiments. Methods: Clinical examinations, genome-wide positional mapping, and sequencing were followed by quantitative polymerase chain reaction and western blot of the protein SVBP and its interaction partners. We then knocked down the gene in rat primary hippocampal neurons and evaluated the consequences on synapses. Results: We identified a founder, homozygous stop-gain variant in SVBP (c.82C>T; p.[Gln28*]) in four affected individuals from two independent families with intellectual disability, microcephaly, ataxia, and muscular hypotonia. SVBP encodes a small chaperone protein that transports and stabilizes two angiogenesis regulators, VASH1 and VASH2. The altered protein is unstable and nonfunctional since transfected HeLa cells with mutant SVBP did not reveal evidence for immunoreactive SVBP protein fragments and cotransfection with VASH1 showed a severe reduction of VASH1 in medium and cell lysate. Knocking down Svbp in rat primary hippocampal neurons led to a significant decrease in the number of excitatory synapses. Conclusion: SVBP is not only involved in angiogenesis, but also has vital functions in the central nervous system. Biallelic loss-of-function variants in SVBP lead to intellectual disability.
CRIS-Team Scopus Importer:2019-07-09
Keywords: CCD23; hippocampal neurons; intellectual disability; NGS; VASH1

Loss-of-function truncating and missense variants in NSD2 cause decreased methylation activity and are associated with a distinct neurodevelopmental phenotype - Zanoni, P.; Steindl, K.; Sengupta, D.; Sticht, Heinrich; Joset, P.; Baar, A.; Van Ravenswaaij-Arts, C. M. A.; Shinawi, M.; Maystadt, I.; Belnap, N.; Benoit, V.; De Vries, B. B. A.; et al. (EUROPEAN JOURNAL OF HUMAN GENETICS, 2020)
CRIS-Team WoS Importer:2021-01-22

Loss of gene information: Discrepancies between rna sequencing, cdna microarray, and qrt-pcr - Rachinger, Nicole; Fischer, Stefan; Böhme, Ines; Linck-Paulus, Lisa; Kuphal, Silke; Kappelmann-Fenzl, Melanie; Boßerhoff, Anja Katrin (International Journal of Molecular Sciences, 2021)
Molecular analyses of normal and diseased cells give insight into changes in gene expression and help in understanding the background of pathophysiological processes. Years after cDNA microarrays were established in research, RNA sequencing (RNA-seq) became a key method of quan-titatively measuring the transcriptome. In this study, we compared the detection of genes by each of the transcriptome analysis methods: cDNA array, quantitative RT-PCR, and RNA-seq. As expected, we found differences in the gene expression profiles of the aforementioned techniques. Here, we present selected genes that exemplarily demonstrate the observed differences and calculations to reveal that a strong RNA secondary structure, as well as sample preparation, can affect RNA-seq. In summary, this study addresses an important issue with a strong impact on gene expression analysis in general. Therefore, we suggest that these findings need to be considered when dealing with data from transcriptome analyses.
CRIS-Team Scopus Importer:2021-09-10
Keywords: CDNA microarray; Free energy of the RNA secondary structure; QRT-PCR; RNA sequencing; Secondary struc-ture; Transcriptome analysis

Loss of Glycine Transporter 1 Causes a Subtype of Glycine Encephalopathy with Arthrogryposis and Mildly Elevated Cerebrospinal Fluid Glycine - Kurolap, Alina; Armbruster, Anja; Hershkovitz, Tova; Hauf, Katharina; Mory, Adi; Paperna, Tamar; Hannappel, Ewald; Tal, Galit; Nijem, Yusif; Sella, Ella; Mahajnah, Muhammad; Ilivitzki, Anat; et al. (American Journal of Human Genetics, 2016)
Glycine is a major neurotransmitter that activates inhibitory glycine receptors and is a co-agonist for excitatory glutamatergic N-methyl-D-aspartate (NMDA) receptors. Two transporters, GLYT1 and GLYT2, regulate extracellular glycine concentrations within the CNS. Dysregulation of the extracellular glycine has been associated with hyperekplexia and nonketotic hyperglycinemia. Here, we report four individuals from two families who presented at birth with facial dysmorphism, encephalopathy, arthrogryposis, hypotonia progressing to hypertonicity with startle-like clonus, and respiratory failure. Only one individual survived the respiratory failure and was weaned off ventilation but has significant global developmental delay. Mildly elevated cerebrospinal fluid (CSF) glycine and normal serum glycine were observed in two individuals. In both families, we identified truncating mutations in SLC6A9, encoding GLYT1. We demonstrate that pharmacologic or genetic abolishment of GlyT1 activity in mice leads to mildly elevated glycine in the CSF but not in blood. Additionally, previously reported slc6a9-null mice and zebrafish mutants also display phenotypes consistent with the affected individuals we examined. Our data suggest that truncating SLC6A9 mutations lead to a distinct human neurological syndrome hallmarked by mildly elevated CSF glycine and normal serum glycine.
EVALuna2:33708

Loss of PHF6 leads to aberrant development of human neuron-like cells - Fliedner, Anna; Gregor, Anne; Ferrazzi, Fulvia; Ekici, Arif Bülent; Sticht, Heinrich; Zweier, Christiane (Scientific Reports, 2020)
Pathogenic variants in PHD finger protein 6 (PHF6) cause Borjeson–Forssman–Lehmann syndrome (BFLS), a rare X-linked neurodevelopmental disorder, which manifests variably in both males and females. To investigate the mechanisms behind overlapping but distinct clinical aspects between genders, we assessed the consequences of individual variants with structural modelling and molecular techniques. We found evidence that de novo variants occurring in females are more severe and result in loss of PHF6, while inherited variants identified in males might be hypomorph or have weaker effects on protein stability. This might contribute to the different phenotypes in male versus female individuals with BFLS. Furthermore, we used CRISPR/Cas9 to induce knockout of PHF6 in SK-N-BE (2) cells which were then differentiated to neuron-like cells in order to model nervous system related consequences of PHF6 loss. Transcriptome analysis revealed a broad deregulation of genes involved in chromatin and transcriptional regulation as well as in axon and neuron development. Subsequently, we could demonstrate that PHF6 is indeed required for proper neuron proliferation, neurite outgrowth and migration. Impairment of these processes might therefore contribute to the neurodevelopmental and cognitive dysfunction in BFLS.
CRIS-Team Scopus Importer:2020-11-13

Loss of Protein Kinase Csnk2b/CK2 beta at Neuromuscular Junctions Affects Morphology and Dynamics of Aggregated Nicotinic Acetylcholine Receptors, Neuromuscular Transmission, and Synaptic Gene Expression - Eiber, Nane; Rehman, Michael; Kravic, Bojana; Rudolf, Ruediger; Sandri, Marco; Hashemolhosseini, Said (Cells, 2019)
The protein kinase Csnk2/CK2 is important for cell proliferation, differentiation, and survival. Previously, we showed that CK2 binds distinctive proteins at neuromuscular junctions (NMJs) of mice and phosphorylates some of them. CK2 likely stabilizes clustered nicotinic acetylcholine receptors (AChRs). In the absence of the beta-subunit of CK2 in skeletal muscle fibers, mice develop an age-dependent decrease of grip strength accompanied by NMJ fragmentation and impairments of neuromuscular transmission. However, the precise role of CK2 beta regarding the clustering of AChRs and downstream signaling at NMJs is unknown. Here, we compared conditional CK2 beta-deficient mice with controls and found in the mutants (1) a lower decrement of endplate potentials after repetitive stimulation and decrements of nerve-evoked compound muscle action potentials decayed more rapidly after synaptic transmission was partially blocked, (2) that their muscle weakness was partially rescued by administration of an acetylcholine esterase inhibitor, (3) fragmented NMJs and impaired AChR clustering was detected in muscles and cultured muscle cells, (4) enlarged myonuclei, (5) impaired synaptic gene expression, and (6) a high turnover rate of their AChR clusters in vivo. Altogether, our data demonstrate a role for CK2 at the NMJ by maintaining a high density of AChRs and ensuring physiological synaptic gene expression.
CRIS-Team WoS Importer:2019-09-24

Loss of SOX10 function contributes to the phenotype of human Merlin-null schwannoma cells. - Wegner, Michael; Sock, Elisabeth; et al. (Brain, 2013)
Loss of the Merlin tumour suppressor causes abnormal de-differentiation and proliferation of Schwann cells and formation of schwannoma tumours in patients with neurofibromatosis type 2. Within the mature peripheral nerve the normal development, differentiation and maintenance of myelinating and non-myelinating Schwann cells is regulated by a network of transcription factors that include SOX10, OCT6 (now known as POU3F1), NFATC4 and KROX20 (also known as Egr2). We have examined for the first time how their regulation of Schwann cell development is disrupted in primary human schwannoma cells. We find that induction of both KROX20 and OCT6 is impaired, whereas enforced expression of KROX20 drives both myelin gene expression and cell cycle arrest in Merlin-null cells. Importantly, we show that human schwannoma cells have reduced expression of SOX10 protein and messenger RNA. Analysis of mouse SOX10-null Schwann cells shows they display many of the characteristics of human schwannoma cells, including increased expression of platelet derived growth factor receptor beta (PDGFRB) messenger RNA and protein, enhanced proliferation, increased focal adhesions and schwannoma-like morphology. Correspondingly, reintroduction of SOX10 into human Merlin-null cells restores the ability of these cells to induce KROX20 and myelin protein zero (MPZ), localizes NFATC4 to the nucleus, reduces cell proliferation and suppresses PDGFRB expression. Thus, we propose that loss of the SOX10 protein, which is vital for normal Schwann cell development, is also key to the pathology of Merlin-null schwannoma tumours. © 2013 The Author.
UnivIS-Import:2015-03-09:Pub.2013.med.IB.LPCIPDBI.lossof
Keywords: KROX20; merlin; Schwann; schwannoma; SOX10

Low amounts of bisecting glycans characterize cerebrospinal fluid-borne IgG - Knopf, Jasmin; Magorivska, Iryna; Maier, Jan-Niklas; Spitzer, Philipp; Bilyy, Rostyslav; Biermann, Mona; Hychka, Kateryna; Bondt, Albert; Wuhrer, Manfred; Toes, Rene E. M.; Schett, Georg; Herrmann, Martin; et al. (Journal of Neuroimmunology, 2018)
Immunoglobulin G (IgG) harbors a conserved N-glycosylation site which is important for its effector functions. Changes in glycosylation of IgG occur in many autoimmune diseases but also in physiological conditions. Therefore, the glycosylation pattern of serum IgG is well characterized. However, limited data is available on the glycosylation pattern of IgG in cerebrospinal fluid (CSF) compared to serum. Here, we report significantly reduced levels of bisected glycans in CSF IgG. Galactosylation and sialylation of IgG4 also differed significantly. Therefore, we propose a common mechanism mediating glycosylation changes of IgG at the transition from serum to CSF in steady state conditions.
EVALuna2:34466

MAGOH and MAGOHB Knockdown in Melanoma Cells Decreases Nonsense-Mediated Decay Activity and Promotes Apoptosis via Upregulation of GADD45A - Söderberg, Agnes; Meißgeier, Tina; Boßerhoff, Anja Katrin; Linck-Paulus, Lisa (Cells, 2022)
Cutaneous malignant melanoma is a highly proliferative and aggressive skin cancer with a steadily increasing incidence and a low long-term survival rate after metastatic progression. The protein MAGOH and its highly identical homologue MAGOHB are core components of the exon junction complex (EJC), which regulates splicing, stability and translation of mRNAs. The EJC, and especially MAGOH, has been shown to be involved in the development and progression of several cancers. In melanoma, the expression and function of both homologues remain essentially unexplored. This study identifies high MAGOH and MAGOHB protein expression in cutaneous melanoma cell lines and patient derived tissue samples. An siRNA-mediated knockdown of MAGOH significantly inhibits melanoma cell proliferation. The loss of MAGOH does not affect cell cycle progression, but induces apoptosis, an effect that is enhanced by a simultaneous knockdown of MAGOH and MAGOHB. MAGOH and MAGOHB do not influence the expression of the pro-apoptotic protein Bcl-XS or exon skipping. However, the knockdown of MAGOH and MAGOHB strongly decreases nonsense-mediated decay (NMD) activity, leading to an upregulation of the pro-apoptotic protein GADD45A. In conclusion, simultaneous inhibition of MAGOH and MAGOHB expression substantially affects cell survival, indicating both MAGOH homologues as promising new targets for the treatment of melanoma.
CRIS-Team Scopus Importer:2022-12-23
Keywords: exon junction complex; GADD45A; MAGOH; melanoma; nonsense-mediated decay

Manipulation of plant innate immunity and gibberellin as factor of compatibility in the mutualistic association of barley roots with Piriformospora indica - Schaefer, Patrick; Pfiffi, Stefanie; Voll, Lars M.; Zajic, Doreen; Chandler, Peter M.; Waller, Frank; Scholz, Uwe; Pons-Kuehnemann, Joern; Sonnewald, Sophia; Sonnewald, Uwe; Kogel, Karl-Heinz (Plant Journal, 2009)
P>Fungi of the order Sebacinales (Basidiomycota) are involved in a wide spectrum of mutualistic symbioses with various plants, thereby exhibiting unique potential for biocontrol strategies. Piriformospora indica, a model organism of this fungal order, is able to increase the biomass and grain yield of crop plants, and induces local and systemic resistance to fungal diseases and tolerance to abiotic stress. To elucidate the molecular basis for root colonization, we characterized the interaction of P. indica with barley roots by combining global gene expression profiling, metabolic profiling, and genetic studies. At the metabolic level, we show that fungal colonization reduces the availability of free sugars and amino acids to the root tip. At the transcriptional level, consecutive interaction stages covering pre-penetration-associated events and progressing through to root colonization showed differential regulation of signal perception and transduction components, secondary metabolism, and genes associated with membrane transport. Moreover, we observed stage-specific up-regulation of genes involved in phytohormone metabolism, mainly encompassing gibberellin, auxin and abscisic acid, but salicylic acid-associated gene expression was suppressed. The changes in hormone homoeostasis were accompanied with a general suppression of the plant innate immune system. Further genetic studies showed reduced fungal colonization in mutants that are impaired in gibberellin synthesis as well as perception, and implicate gibberellin as a modulator of the root's basal defence. Our data further reveal the complexity of compatibility mechanisms in host-microbe interactions, and identify gibberellin signaling as potential target for successful fungi.
Keywords: compatibility; gibberellin; plant defence; plant hormone; symbiosis; mutualism

MAP4-dependent regulation of microtubule formation affects centrosome, cilia, and golgi architecture as a central mechanism in growth regulation - Zahnleiter, Diana; Hauer, Nadine; Keßler, Kristin; Uebe, Steffen; Sugano, Yuya; Neuhauss, Stephan C. F.; Gießl, Andreas; Ekici, Arif Bülent; Blessing, Holger; Sticht, Heinrich; Dörr, Helmuth-Günther; Reis, André; et al. (Human Mutation, 2015)
Numerous genes are involved in human growth regulation. Recently, autosomal-recessive inherited variants in centrosomal proteins have been identified in Seckel syndrome, primary microcephaly, or microcephalic osteodysplastic primary dwarfism. Common hallmarks of these syndromic forms are severe short stature and microcephaly. In a consanguineous family with two affected children with severe growth retardation and normocephaly, we used homozygosity mapping and next-generation sequencing to identify a homozygous MAP4 variant. MAP4 is a major protein for microtubule assembly during mitosis. High-expression levels in the somite boundaries of zebrafish suggested a role in growth and body segment patterning. The identified variant affects binding sites of kinases necessary for dynamic instability of microtubule formation. We found centrosome amplifications in mitotic fibroblast cells in vivo and in vitro. These numeric centrosomal aberrations were also present during interphase resulting in aberrant ciliogenesis. Furthermore, affected cells showed a dysfunction of the microtubule-dependent assembly of the Golgi apparatus, indicated by a significant lack of compactness of Golgi membranes. These observations demonstrated that MAP4 mutations contribute to the clinical spectrum of centrosomal defects and confirmed the complex role of a centrosomal protein in centrosomal, ciliary, and Golgi regulation associated with severe short stature.
EVALuna2:9244

Mast cell chymase promotes angiogenesis and lymphangiogenesis mediated by activation of melanoma inhibitory activity gene family members in oral squamous cell carcinoma - Kurihara–Shimomura, Miyako; Sasahira, Tomonori; Shimomura, Hiroyuki; Boßerhoff, Anja Katrin; Kirita, Tadaaki (International Journal of Oncology, 2020)
Mast cells (MCs) are present in the tumor stroma, and MCs that express the mast cell–specific proteases tryptase and chymase (MCTC) exhibit several tumor–related functions. It was previously reported that melanoma inhibitory activity (MIA) gene family members, including MIA, MIA2, and transport and Golgi organization protein 1 (TANGO), possess oncogenic functions in oral squamous cell carcinoma (OSCC). However, the relationships between MCTC, and clinicopathological characteristics and activation of the MIA gene family in OSCC remain unknown. In the present study, the functional roles of MCTC in patients with OSCC were investigated using immunohistochemistry and reverse transcription–quantitative PCR. In addition, the effects of extracellular chymase on oral cancer cells were examined. In patients with OSCC, MCTC density was significantly affected by tumor progression and nodal metastasis, and was correlated with vessel density. MCTC density was also correlated with MIA and MIA2 expression. In OSCC cells, extracellular chymase promoted the secretion of vascular endothelial growth factor family proteins, and the transmigration and adhesion of HSC3 cells to endothelial cells; knockdown of MIA, MIA2 and TANGO attenuated these effects. The present findings indicated that MCTC act as tumor–progressive factors in OSCC via the activation and secretion of MIA and MIA2, and the induction of angiogenesis and lymphangiogenesis.
CRIS-Team Scopus Importer:2020-03-27
Keywords: Chymase; Mast cell; MIA gene family; Oral cancer

Matricellular Protein SPARCL1 Regulates Blood Vessel Integrity and Antagonizes Inflammatory Bowel Disease - Regensburger, Daniela; Tenkerian, Clara; Pürzer, Victoria; Schmid, Benjamin; Wohlfahrt, Thomas; Stolzer, Iris; Lopez Posadas, Rocío; Günther, Claudia; Waldner, Maximilian; Becker, Christoph; Sticht, Heinrich; Petter, Katja; et al. (Inflammatory Bowel Diseases, 2021)
Background The understanding of vascular plasticity is key to defining the role of blood vessels in physiologic and pathogenic processes. In the present study, the impact of the vascular quiescence marker SPARCL1 on angiogenesis, capillary morphogenesis, and vessel integrity was evaluated. Methods Angiogenesis was studied using the metatarsal test, an ex vivo model of sprouting angiogenesis. In addition, acute and chronic dextran sodium sulfate colitis models with SPARCL1 knockout mice were applied. Results This approach indicated that SPARCL1 inhibits angiogenesis and supports vessel morphogenesis and integrity. Evidence was provided that SPARCL1-mediated stabilization of vessel integrity counteracts vessel permeability and inflammation in acute and chronic dextran sodium sulfate colitis models. Structure-function analyses of purified SPARCL1 identified the acidic domain of the protein necessary for its anti-angiogenic activity. Conclusions Our findings inaugurate SPARCL1 as a blood vessel–derived anti-angiogenic molecule required for vessel morphogenesis and integrity. SPARCL1 opens new perspectives as a vascular marker of susceptibility to colitis and as a therapeutic molecule to support blood vessel stability in this disease. <br
Keywords: angiogenesis; blood vessel; DSS colitis; endothelial cell; inflammatory bowel disease; permeability; SPARCL1

Matrix stiffness mechanosensing modulates the expression and distribution of transcription factors in Schwann cells - Rosso, Gonzalo; Wehner, Daniel; Schweitzer, Christine; Sock, Elisabeth; Guck, Jochen; Shahin, Victor; Möllmert, Stephanie (Bioengineering & Translational Medicine, 2021)
After peripheral nerve injury, mature Schwann cells (SCs) de-differentiate and undergo cell reprogramming to convert into a specialized cell repair phenotype that promotes nerve regeneration. Reprogramming of SCs into the repair phenotype is tightly controlled at the genome level and includes downregulation of pro-myelinating genes and activation of nerve repair-associated genes. Nerve injuries induce not only biochemical but also mechanical changes in the tissue architecture which impact SCs. Recently, we showed that SCs mechanically sense the stiffness of the extracellular matrix and that SC mechanosensitivity modulates their morphology and migratory behavior. Here, we explore the expression levels of key transcription factors and myelin-associated genes in SCs, and the outgrowth of primary dorsal root ganglion (DRG) neurites, in response to changes in the stiffness of generated matrices. The selected stiffness range matches the physiological conditions of both utilized cell types as determined in our previous investigations. We find that stiffer matrices induce upregulation of the expression of transcription factors Sox2, Oct6, and Krox20, and concomitantly reduce the expression of the repair-associated transcription factor c-Jun, suggesting a link between SC substrate mechanosensing and gene expression regulation. Likewise, DRG neurite outgrowth correlates with substrate stiffness. The remarkable intrinsic physiological plasticity of SCs, and the mechanosensitivity of SCs and neurites, may be exploited in the design of bioengineered scaffolds that promote nerve regeneration upon injury.
CRIS-Team Scopus Importer:2021-10-01
Keywords: cell plasticity; extracellular matrix stiffness; mechanosensing; nerve regeneration; neuron; Schwann cell

Media Modulation based Molecular Communication - Brand, Lukas; Garkisch, Moritz; Lotter, Sebastian; Schäfer, Maximilian; Burkovski, Andreas; Sticht, Heinrich; Castiglione, Kathrin; Schober, Robert (IEEE Transactions on Communications, 2022)
In conventional molecular communication (MC) systems, the signaling molecules used for information transmission are stored, released, and then replenished by a transmitter (TX). However, the replenishment of signaling molecules at the TX is challenging in practice. Furthermore, in most envisioned MC applications, e.g., in the medical field, it is not desirable to insert the TX into the MC system, as this might impair natural biological processes. In this paper, we propose the concept of media modulation based MC where the TX is placed outside the channel and utilizes signaling molecules already present inside the system. The signaling molecules can assume different states which can be switched by external stimuli. Hence, in media modulation based MC, the TX modulates information into the state of the signaling molecules. In particular, we exploit the group of photochromic molecules, which undergo light-induced reversible state transitions, for media modulation. We study the usage of these molecules for information transmission in a three-dimensional duct system, which contains an eraser, a TX, and a receiver for erasing, writing, and reading of information via external light, respectively. We develop a statistical model for the received signal which accounts for the distribution of the signaling molecules in the system, the initial states of the signaling molecules, the reliability of the state control mechanism, the randomness of irrepressible, spontaneous state switching, and the randomness of molecule propagation. We adopt a maximum likelihood detector and show that it can be reduced to a threshold based detector. Furthermore, we derive analytical expressions for the optimal threshold value and the resulting bit error rate (BER), respectively. Both the statistical model and BER results are verified by computer simulations. Our results reveal that media modulation enables reliable information transmission, validating it as a promising alternative to MC based on molecule emitting TXs.<br

Melanocyte-Specific Expression Of Dopachrome Tautomerase Is Dependent On Synergistic Gene Activation By The Sox10 And Mitf Transcription Factors. - Wegner, Michael; et al. (Febs Letters, 2004)
Sox10 regulates melanocyte development at least partly through its stimulatory effect on Mitf gene expression. Here, we characterize the gene for dopachrome tautomerase (Dct/Trp2) as the second direct Sox10 target in melanocytes, arguing for the existence of Sox10 functions in melanocytes that are independent of its epistatic relationship to Mitf. Sox10 responsiveness was mediated by multiple binding sites within the proximal Dct/Trp2 promoter which display varying affinities and bind Sox10 monomers or dimers. Mitf synergistically enhanced Sox10-dependent activation of the Dct/Trp2 promoter. Synergy appears mechanistically complex and requires both direct binding of Sox10 to the promoter and the protein's transactivation domain. © 2003 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2004.med.IB.LPCIPDBI.melano
Keywords: Dopachrome tautomerase; High-mobility group; Sox; Sry; Tyrosinase-related protein 2

Melanoma development: Molecular biology, genetics and clinical application - Boßerhoff, Anja Katrin (Springer International Publishing, 2017)
This book focuses on malignant melanoma, discussing the current state of scientific knowledge and providing insights into the underlying basic mechanisms, the molecular changes, genetics and genomics. Human Melanoma is a dangerous type of skin cancer affecting an increasing population, and a better understanding of its development will help in finding sophisticated targeted therapies. The second revised edition features the latest research findings and offers updates on the latest advances and potential novel melanoma therapies. It is a valuable resource for researchers and clinicians working in the fields of melanoma, cancer research and therapy as well as dermatology.
CRIS-Team Scopus Importer:2022-08-05

Melanoma sponge on pigmentation gene to reduce tumour-suppressive microRNAs - Dietrich, Peter; Boßerhoff, Anja Katrin (Pigment Cell & Melanoma Research, 2017)
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Membrane Transporters and Channels in Melanoma - Böhme-Schäfer, Ines; Schoenherr, Roland; Eberle, Juergen; Boßerhoff, Anja Katrin (Reviews of Physiology Biochemistry and Pharmacology, 2021)
Recent research has revealed that ion channels and transporters can be important players in tumor development, progression, and therapy resistance in melanoma. For example, members of the ABC family were shown to support cancer stemness-like features in melanoma cells, while several members of the TRP channel family were reported to act as tumor suppressors.
CRIS-Team WoS Importer:2022-03-18
Keywords: Apoptosis; Cell proliferation; Channels; Melanocyte; Melanoma; Metastasis; Mutation; Nevus; Prognosis; Transporters; Tumor development; Tumor progression

Merging bioresponsive release of insulin-like growth factor I with 3D printable thermogelling hydrogels - Beudert, Matthias; Hahn, Lukas; Horn, Anselm; Hauptstein, Niklas; Sticht, Heinrich; Meinel, Lorenz; Luxenhofer, Robert; Gutmann, Marcus; Luehmann, Tessa (Journal of Controlled Release, 2022)
3D printing of biomaterials enables spatial control of drug incorporation during automated manufacturing. This study links bioresponsive release of the anabolic biologic, insulin-like growth factor-I (IGF-I) in response to matrix metalloproteinases (MMP) to 3D printing using the block copolymer of poly(2-methyl-2-oxazoline) and thermoresponsive poly(2-n-propyl-2-oxazine) (POx-b-POzi). For that, a chemo-enzymatic synthesis was deployed, ligating IGF-I enzymatically to a protease sensitive linker (PSL), which was conjugated to a POx-b-POzi copolymer. The product was blended with the plain thermogelling POx-b-POzi hydrogel. MMP exposure of the resulting hydrogel triggered bioactive IGF-I release. The bioresponsive IGF-I containing POx-b-POzi hydrogel system was further detailed for shape control and localized incorporation of IGF-I via extrusion 3D printing for future applications in biomedicine and biofabrication.<br
Keywords: Matrix metalloproteinase; IGF-I; POx; Poly(2-methyl-2-oxazoline)-b-poly(2-propyl-2-oxazine); Biofabrication; 3D printing; Transglutaminase

Metabotropic glutamate receptors and interacting proteins: evolving drug targets - Enz, Ralf (Current Drug Targets, 2012)
The correct targeting, localization, regulation and signaling of metabotropic glutamate receptors (mGluRs) represent major mechanisms underlying the complex function of neuronal networks. These tasks are accomplished by the formation of synaptic signal complexes that integrate functionally related proteins such as neurotransmitter receptors, enzymes and scaffold proteins. By these means, proteins interacting with mGluRs are important regulators of glutamatergic neurotransmission. Most described mGluR interaction partners bind to the intracellular C-termini of the receptors. These domains are extensively spliced and phosphorylated, resulting in a high variability of binding surfaces offered to interacting proteins. Malfunction of mGluRs and associated proteins are linked to neurodegenerative and neuropsychiatric disorders including addiction, depression, epilepsy, schizophrenia, Alzheimer's, Huntington's and Parkinson's disease. MGluR associated signal complexes are dynamic structures that assemble and disassemble in response to the neuronal fate. This, in principle, allows therapeutic intervention, defining mGluRs and interacting proteins as promising drug targets. In the last years, several studies elucidated the geometry of mGluRs in contact with regulatory proteins, providing a solid fundament for the development of new therapeutic strategies. Here, I will give an overview of human disorders directly associated with mGluR malfunction, provide an up-to-date summary of mGluR interacting proteins and highlight recently described structures of mGluR domains in contact with binding partners.
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Metabotropic glutamate receptors are differentially regulated under elevated intraocular pressure. - Dyka,; May,; Enz, Ralf (Journal of Neurochemistry, 2004)
Glaucoma is a leading cause of blindness, ultimatively resulting in the apoptotic death of retinal ganglion cells. However, molecular mechanisms involved in ganglion cell death are poorly understood. While the involvement of ionotropic glutamate receptors has been extensively studied, virtually nothing is known about its metabotropic counterparts. Here, we compared the retinal gene expression of metabotropic glutamate receptors (mGluR) in eyes with normal and elevated intraocular pressure (IOP) of DBA/2J mice, a model for secondary angle-closure glaucoma using RT-PCR and immunohistochemistry. Elevated IOP in DBA/2J mice significantly increased retinal gene expression of mGluR1a, mGluR2, mGluR4a, mGluR4b, mGluR6 and mGluR7a when compared to C57BL/6 control animals, while mGluR5a/b and mGluR8a were decreased and no difference was observed for mGluR3 and mGluR8b. Specific antibodies detected an increase of mGluR1a and mGluR5a/b in both synaptic layers and in the ganglion cell layer of the retina under elevated IOP. Because ganglion cell death in DBA/2J mice occurs most likely by apoptotic mechanisms, we demonstrated up-regulation of mGluRs in neurons undergoing apoptosis. In summary, we support the idea that the specific gene regulation of mGluRs is a part of the glaucoma-like pathological process that develops in the eyes of DBA/2J mice.
UnivIS-Import:2017-12-18:Pub.2004.med.IB.profes_1.metabo
Keywords: Apoptosis; Gene expression; Glaucoma; Immunocytochemistry; Retina; RT-PCR

Metabotropic Glutamate Receptors at Ribbon Synapses in the Retina and Cochlea - Klotz-Weigand, Lisa; Enz, Ralf (Cells, 2022)
Our senses define our view of the world. They allow us to adapt to environmental stimuli and are essential for communication and social behaviour. For most humans, seeing and hearing are central senses for their daily life. Our eyes and ears respond to an extraordinary broad range of stimuli covering about 12 log units of light intensity or acoustic power, respectively. The cellular basis is represented by sensory cells (photoreceptors in the retina and inner hair cells in the cochlea) that convert sensory inputs into electrical signals. Photoreceptors and inner hair cells have devel-oped a specific pre-synaptic structure, termed synaptic ribbon, that is decorated with numerous vesicles filled with the excitatory neurotransmitter glutamate. At these ribbon synapses, glutama-tergic signal transduction is guided by distinct sets of metabotropic glutamate receptors (mGluRs). MGluRs belong to group II and III of the receptor classification can inhibit neuronal activity, thus protecting neurons from overstimulation and subsequent degeneration. Consequently, dysfunction of mGluRs is associated with vision and hearing disorders. In this review, we introduce the principle characteristics of ribbon synapses and describe group II and III mGluRs in these fascinating structures in the retina and cochlea.
CRIS-Team Scopus Importer:2022-04-08
Keywords: Bipolar cell; Cochlea; Dimerization; Inner hair cell; Metabotropic glutamate receptor; Photoreceptor; Protein interaction; Retina; Ribbon synapse; Short linear motif

Methocarbamol blocks muscular Nav1.4 channels and decreases isometric force of mouse muscles - Zhang, Yaxin; Otto, Philipp; Qin, Lu; Eiber, Nane; Hashemolhosseini, Said; Kröger, Stephan; Brinkmeier, Heinrich (Muscle & Nerve, 2020)
Background: The muscle relaxant methocarbamol is widely used for the treatment of muscle spasms and pain syndromes. To elucidate molecular mechanisms of its action, we studied its influence on neuromuscular transmission, on isometric muscle force, and on voltage-gated Na+ channels. Methods: Neuromuscular transmission was investigated in murine diaphragm-phrenic nerve preparations and muscle force studied on mouse soleus muscles. Nav1.4 channels and Nav1.7 channels were functionally expressed in eukaryotic cell lines. Results: Methocarbamol, at 2 mM, decreased the decay of endplate currents, slowed the decay of endplate potentials and reduced tetanic force of soleus muscles. The drug reversibly inhibited current flow through muscular Nav1.4 channels, while neuronal Nav1.7 channels were unaffected. Conclusions: The study provides evidence for peripheral actions of methocarbamol on skeletal muscle. Muscular Na+ channels are a molecular target of methocarbamol. Since Nav1.7 currents were unaffected, methocarbamol is unlikely to exert its analgesic effect by directly blocking Nav1.7 channels.
CRIS-Team Scopus Importer:2020-11-06
Keywords: methocarbamol; muscle force; muscle relaxant; neuromuscular transmission; voltage-gated Na

mGCMa is a murine transcription factor that overrides cell fate decisions in Drosophila - Wegner, Michael; et al. (Mechanisms of Development, 1999)
During neural development of Drosophila melanogaster, Glial Cells Missing (GCM), functions as a binary switch that promotes glial cell fate while simultaneously inhibiting the neuronal fate. Sequence similarities between GCM and the recently identified mouse protein mGCMa are strictly limited to the aminoterminal DNA-binding domain. Here we show that mGCMa efficiently activates transcription in Drosophila cells just as Drosophila GCM activates transcription in mammalian cells. Transactivation potential was present in two separate regions of mGCMa outside the DNA-binding domain. One of them mapped to the carboxyterminal 88 amino acids, a location corresponding exactly to the transactivation domain of GCM. Similarities between GCM and mGCMa were also observed in vivo. Overexpression of mGCMa in the developing nervous system of Drosophila embryos led to an increase in glial-like cells at the expense of neurons. Outside the neurogenic region, mGCMa interfered with epidermal development, as evident from changes in celt morphology and marker expression. Thus, mGCMa function is at least partially independent of a cell's predisposition to a neural fate. The potent activity of mGCMa in Drosophila and its extensive functional similarities to GCM make mGCMa a candidate for a regulator of mouse glial development.
UnivIS-Import:2015-03-05:Pub.1999.med.IB.LPCIPDBI.mgcmai
Keywords: Determination; Glia; Glial Cells Missing; Neural development; Transcription

MGluR7 is a presynaptic metabotropic glutamate receptor at ribbon synapses of inner hair cells - Klotz, Lisa; Enz, Ralf (The FASEB Journal, 2021)
Glutamate is the most pivotal excitatory neurotransmitter in the central nervous system. Metabotropic glutamate receptors (mGluRs) dimerize and can couple to inhibitory intracellular signal cascades, thereby protecting glutamatergic neurons from excessive excitation and cell death. MGluR7 is correlated with age-related hearing deficits and noise-induced hearing loss; however its exact localization in the cochlea is unknown. Here, we analyzed the expression and localization of mGluR7a and mGluR7b in mouse cochlear wholemounts in detail, using confocal microscopy and 3D reconstructions. We observed a presynaptic localization of mGluR7a at inner hair cells (IHCs), close to the synaptic ribbon. To detect mGluR7b, newly generated antibodies were characterized and showed co-localization with mGluR7a at IHC ribbon synapses. Compared to the number of synaptic ribbons, the numbers of mGluR7a and mGluR7b puncta were reduced at higher frequencies (48 to 64 kHz) and in older animals (6 and 12 months). Previously, we reported a presynaptic localization of mGluR4 and mGluR8b at this synapse type. This enables the possibility for the formation of homo- and/or heterodimeric receptors composed of mGluR4, mGluR7a, mGluR7b and mGluR8b at IHC ribbon synapses. These receptor complexes might represent new molecular targets suited for pharmacological concepts to protect the cochlea against noxious stimuli and excitotoxicity.
CRIS-Team Scopus Importer:2021-11-05
Keywords: cochlea; inner hair cell; metabotropic glutamate receptor; mGlu; ribbon synapse

MIA/CD-RAP Regulates MMP13 and Is a Potential New Disease-Modifying Target for Osteoarthritis Therapy - Stäbler, Sebastian; Lichtblau, Adrian; Gurbiel, Slavyana; Schubert, Thomas; Riechers, Alexander; Rottensteiner-Brandl, Ulrike; Boßerhoff, Anja Katrin (Cells, 2023)
Melanoma inhibitory activity/cartilage-derived retinoicacid-sensitive protein (MIA/CD-RAP) is a protein expressed and secreted by chondrocytes and cartilaginous tissues. MIA/CD-RAP-deficient mice develop milder osteoarthritis than wildtype mice. In this study, we investigated MIA/CD-RAP downstream targets to explain this reduced disease development. As a possible mediator, we could detect matrix metalloproteinase 13 (MMP13), and the influence of MIA/CD-RAP on MMP13 regulation was analyzed in vitro using SW1353 chondrosarcoma cells and primary chondrocytes. The femoral head cartilage of WT and MIA/CD-RAP −/− mice were cultured ex vivo to further investigate MMP13 activity. Finally, osteoarthritis was surgically induced via DMM in C57BL/6 mice, and the animals were treated with an MIA/CD-RAP inhibitory peptide by subcutaneously implanted pellets. MMP13 was regulated by MIA/CD-RAP in SW1353 cells, and MIA/CD-RAP −/− murine chondrocytes showed less expression of MMP13. Further, IL-1β-treated MIA/CD-RAP −/− chondrocytes displayed less MMP13 expression and activity. Additionally, MIA/CD-RAP-deficient ex vivo cultured cartilage explants showed less MMP13 activity as well as reduced cartilage degradation. The mice treated with the MIA/CD-RAP inhibitory peptide showed less osteoarthritis development. Our findings revealed MIA/CD-RAP as a new regulator of MMP13 and highlighted its role as a potential new target for osteoarthritis therapy.
CRIS-Team Scopus Importer:2023-02-03
Keywords: MIA/CD-RAP; MMP13; osteoarthritis; signaling; therapeutic

MicroRNA-622 is a novel mediator of tumorigenicity in melanoma by targeting Kirsten rat sarcoma - Dietrich, Peter; Kuphal, Silke; Spruss, Thilo; Hellerbrand, Claus; Boßerhoff, Anja Katrin (Pigment Cell & Melanoma Research, 2018)
The network of molecular players is similar when comparing neural crest-derived, actively migrating melanoblasts to melanoma cells. However, melanoblasts are sensitive to differentiation-initiating signals at their target site (epidermis), while melanoma cells maintain migratory and undifferentiated features. We aimed at identifying downregulated genes in melanoma that are particularly upregulated in melanoblasts. Loss of such genes could contribute to stabilization of a dedifferentiated, malignant phenotype in melanoma. We determined that microRNA-622 (miR-622) expression was strongly downregulated in melanoma cells and tissues compared to melanocytes and melanoblast-related cells. miR-622 expression correlated with survival of patients with melanoma. miR-622 re-expression inhibited clonogenicity, proliferation, and migration in melanoma. Inhibition of miR-622 in melanocytes induced enhanced migration. Kirsten rat sarcoma (KRAS) was identified as a major functional target of miR-622 in melanoma. We conclude that miR-622 is a novel tumor suppressor in melanoma and identify the miR-622-KRAS axis as potential therapeutic target.
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MicroRNA - a contributor to age-associated neural stem cell dysfunction? - Khan, Muhammad Amir; Lie, Dieter Chichung (Aging-Us, 2011)
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MicroRNA miR-204 regulates proliferation and differentiation of oligodendroglia in culture - Wittstatt, Jan; Weider, Matthias; Wegner, Michael; Reiprich, Simone (Glia, 2020)
Oligodendrocytes wrap and physically shield axons of the central nervous system with myelin sheaths, resulting in rapid signal transduction and accurate neuronal function. The complex oligodendroglial development from immature oligodendrocyte precursor cells (OPCs) to myelinating oligodendrocytes (OLs) is profoundly dependent on the activity of transcription factors of the Sox protein family. Target genes of the crucial regulator Sox10 have recently been expanded to microRNAs. Here, we report miR-204 as a novel transcriptional target of Sox10. Regulatory regions of miR-204 show responsiveness to and binding of Sox10 in reporter gene assays and electromobility shift assays. Once expressed, miR-204 inhibits OPC proliferation and facilitates differentiation into OLs in the presence of Sox10 as evident from overexpression in primary rat and mouse oligodendroglial cultures. Phenotypes are at least in part caused by miR-204-dependent repression of the pro-proliferative Ccnd2 and the differentiation inhibiting Sox4. These findings argue that the transcriptional activator Sox10 forces oligodendroglial cells to exit the cell cycle and start differentiation by gene inhibition via miR-204 induction.
CRIS-Team Scopus Importer:2020-03-27
Keywords: glia; microRNA; myelination; proliferation; regulatory network; Sox proteins

MicroRNA-sequencing data analyzing melanoma development and progression - Linck, Lisa; Liebig, Janika; Voeller, Daniel; Eichner, Norbert; Lehmann, Gerhard; Meister, Gunter; Boßerhoff, Anja Katrin (Experimental and Molecular Pathology, 2018)
MicroRNAs (miRNAs) deregulated in melanoma are of growing importance in cancer research. We aimed to define the miRNAome of melanoma cell lines and primary melanocytes by RNA-Seq using identical cell lines as in a published miRNA expression study based on cDNA arrays. We identified 79 miRNAs, which are significantly deregulated during melanoma development. In addition, we could also determine 29 miRNAs being involved in melanoma progression. Interestingly, not all characterized miRNAs derived from cDNA array analyses of our and other groups could be found to be differentially expressed using RNA-Seq analyses, however, new miRNAs, formerly not associated with melanoma, were found to be strongly regulated.
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MicroRNAs in melanocyte and melanoma biology - Mione, Marina; Boßerhoff, Anja Katrin (Pigment Cell & Melanoma Research, 2015)
The importance of microRNAs as key molecular components of cellular processes is now being recognized. Recent reports have shown that microRNAs regulate processes as diverse as protein expression and nuclear functions inside cells and are able to signal extracellularly, delivered via exosomes, to influence cell fate at a distance. The versatility of microRNAs as molecular tools inspires the design of novel strategies to control gene expression, protein stability, DNA repair and chromatin accessibility that may prove very useful for therapeutic approaches due to the extensive manageability of these small molecules. However, we still lack a comprehensive understanding of the microRNA network and its interactions with the other layers of regulatory elements in cellular and extracellular functions. This knowledge may be necessary before we exploit microRNA versatility in therapeutic settings. To identify rules of interactions between microRNAs and other regulatory systems, we begin by reviewing microRNA activities in a single cell type: the melanocyte, from development to disease.
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MicroRNAs promote skeletal muscle differentiation of mesodermal iPSC-derived progenitors - Giacomazzi, Giorgia; Holvoet, Bryan; Trenson, Sander; Caluwe, Ellen; Kravic, Bojana; Grosemans, Hanne; Cortes-Calabuig, Alvaro; Deroose, Christophe M.; Huylebroeck, Danny; Hashemolhosseini, Said; Janssens, Stefan; Mcnally, Elizabeth; et al. (Nature Communications, 2017)
Muscular dystrophies (MDs) are often characterized by impairment of both skeletal and cardiac muscle. Regenerative strategies for both compartments therefore constitute a therapeutic avenue. Mesodermal iPSC-derived progenitors (MiPs) can regenerate both striated muscle types simultaneously in mice. Importantly, MiP myogenic propensity is influenced by somatic lineage retention. However, it is still unknown whether human MiPs have in vivo potential. Furthermore, methods to enhance the intrinsic myogenic properties of MiPs are likely needed, given the scope and need to correct large amounts of muscle in the MDs. Here, we document that human MiPs can successfully engraft into the skeletal muscle and hearts of dystrophic mice. Utilizing non-invasive live imaging and selectively induced apoptosis, we report evidence of striated muscle regeneration in vivo in mice by human MiPs. Finally, combining RNA-seq and miRNA-seq data, we define miRNA cocktails that promote the myogenic potential of human MiPs.
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Mighty bugs: leprosy bacteria turn schwann cells into stem cells. - Wegner, Michael (Cell, 2013)
For intracellular parasites that strongly prefer infecting a particular cell type, systemic spread is challenging. Masaki et al. show that the leprosy bacterium cleverly expands its repertoire by driving dedifferentiation of Schwann cells, their preferred host, to cells with stem cell properties that can subsequently redifferentiate into mesodermal lineages. © 2013 Elsevier Inc.
UnivIS-Import:2015-03-09:Pub.2013.med.IB.LPCIPDBI.mighty

Mimicking titration experiments with MD simulations: A protocol for the investigation of pH-dependent effects on proteins - Socher, Eileen; Sticht, Heinrich (Scientific Reports, 2016)
Protein structure and function are highly dependent on the environmental pH. However, the temporal or spatial resolution of experimental approaches hampers direct observation of pH-induced conformational changes at the atomic level. Molecular dynamics (MD) simulation strategies (e.g. constant pH MD) have been developed to bridge this gap. However, one frequent problem is the sampling of unrealistic conformations, which may also lead to poor pKa predictions. To address this problem, we have developed and benchmarked the pH-titration MD (pHtMD) approach, which is inspired by wet-lab titration experiments. We give several examples how the pHtMD protocol can be applied for pKa calculation including peptide systems, Staphylococcus nuclease (SNase), and the chaperone HdeA. For HdeA, pHtMD is also capable of monitoring pH-dependent dimer dissociation in accordance with experiments. We conclude that pHtMD represents a versatile tool for pKa value calculation and simulation of pH-dependent effects in proteins.

miR-488-5p and its role in melanoma - Arnold, Jessica; Engelmann, Julia C.; Schneider, Nadja; Boßerhoff, Anja Katrin; Kuphal, Silke (Experimental and Molecular Pathology, 2019)
Due to their ability to regulate dozens to hundreds of target genes simultaneously and, therefore, influence several oncogenic pathways at the same time, microRNAs are a fascinating research object in melanoma. MicroRNAs have been identified as regulators of tumor proliferation, invasion and metastasis in melanoma. More precisely, it has been published that dysregulation of miR-488 contibutes to the progression of several cancer entities. However, the biological functions of miR-488, in special miR-488-5p in melanoma, remain unclear. This study showed the involvement of miR-488-5p in Wnt/β-catenin pathway and the function as a tumor suppressor. Transfection of miR-488-5p mimic led to inhibition of proliferation, migration, anchorage independent growth and led to induction of apoptosis. These data indicated that miR-488-5p acts as a tumor suppressor and is lost during melanoma development. The loss of miR-488-5p was confirmed in vivo by in situ hybridization on melanoma tissue.
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miR-488-5p and its role in melanoma - Arnold, Jessica; Engelmann, Julia C.; Schneider, Nadja; Boßerhoff, Anja Katrin; Kuphal, Silke (Experimental and Molecular Pathology, 2020)
Due to their ability to regulate dozens to hundreds of target genes simultaneously and, therefore, influence several oncogenic pathways at the same time, microRNAs are a fascinating research object in melanoma. MicroRNAs have been identified as regulators of tumor proliferation, invasion and metastasis in melanoma. More precisely, it has been published that dysregulation of miR-488 contibutes to the progression of several cancer entities. However, the biological functions of miR-488, in special miR-488-5p in melanoma, remain unclear. This study showed the involvement of miR-488-5p in Wnt/β-catenin pathway and the function as a tumor suppressor. Transfection of miR-488-5p mimic led to inhibition of proliferation, migration, anchorage independent growth and led to induction of apoptosis. These data indicated that miR-488-5p acts as a tumor suppressor and is lost during melanoma development. The loss of miR-488-5p was confirmed in vivo by in situ hybridization on melanoma tissue.
CRIS-Team Scopus Importer:2019-12-13
Keywords: Melanoma; microRNA; Wnt/β-catenin pathway

MiRNAs in malignant melanoma - Mione, Maria; Liebig, Janika; Munoz, Leonel; Boßerhoff, Anja Katrin (Springer International Publishing, 2017)
MicroRNAs (miRNAs) represent a class of small noncoding RNAs, first described in the nematode Caenorhabditis elegans. In 1993, the labs of Victor Ambros (Lee et al. Cell 75:843-854, 1993) and Gary Ruvkun (Wightman et al. Cell 75:855-862, 1993) discovered lin-4, the first member of the inexorably growing family of miRNAs. Interestingly, it was not until the year 2000 that Reinhart and colleagues detected a second miRNA species-let-7 (Reinhart et al. Nature 2000;403:901-906). The finding that the sequence of let-7 was conserved in a large variety of Metazoens from Drosophila to humans (in contrast to lin-4, which is exclusively expressed in Caenorhabditis; Pasquinelli et al. Nature 408:86-89, 2000; Slack et al. Mol Cell 2000;5:659-669, 2000) fueled miRNA research and revealed that this class of molecules is involved in the regulation of gene expression at a posttranscriptional level in presumably every multicellular organism. To date, more than 1800 distinct miRNA species have been identified in the human genome (www.miRNA.org Kozomara and Griffiths-Jones 42(Database issue):D68-73, 2014). Those are estimated to regulate the expression of as much as 60 % of all human transcripts (Friedman et al. Genome Res 2009;19:92-105, 2009). MiRNAs are demonstrably involved in the physiological regulation of multiple cellular processes, such as proliferation, apoptosis, and differentiation. As a consequence, abnormalities in miRNA activity were found to contribute to the pathogenesis and progression of various types of human cancers (reviewed by Mirnezami et al. Eur J Surg Oncol 35:339-347, 2009; Visone and Croce Am J Pathol 2009;174:1131-1138, 2009), including malignant melanoma (reviewed by Mione and Bosserhoff Pigment Cell Melanoma Res 2015;28:340-354).
CRIS-Team Scopus Importer:2022-08-05

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, Annick; Bok, Levinus A.; Cho, Megan T.; Crawford, Heather P.; Dubbs, Holly; Douglas, Ganka; Jobling, Rebekah; Johnson, Diana; Krock, Bryan; et al. (American Journal of Human Genetics, 2018)
Although the role of typical Rho GTPases and other Rho-linked proteins in synaptic plasticity and cognitive function and dysfunction is widely acknowledged, the role of atypical Rho GTPases (such as RHOBTB2) in neurodevelopment has barely been characterized. We have now identified de novo missense variants clustering in the BTB-domain-encoding region of RHOBTB2 in ten individuals with a similar phenotype, including early-onset epilepsy, severe intellectual disability, postnatal microcephaly, and movement disorders. Three of the variants were recurrent. Upon transfection of HEK293 cells, we found that mutant RHOBTB2 was more abundant than the wild-type, most likely because of impaired degradation in the proteasome. Similarly, elevated amounts of the Drosophila ortholog RhoBTB in vivo were associated with seizure susceptibility and severe locomotor defects. Knockdown of RhoBTB in the Drosophila dendritic arborization neurons resulted in a decreased number of dendrites, thus suggesting a role of RhoBTB in dendritic development. We have established missense variants in the BTB-domain-encoding region of RHOBTB2 as causative for a developmental and epileptic encephalopathy and have elucidated the role of atypical Rho GTPase RhoBTB in Drosophila neurological function and possibly dendrite development.
EVALuna2:33715

Mitochondrial Dysfunction in Astrocytes Impairs the Generation of Reactive Astrocytes and Enhances Neuronal Cell Death in the Cortex Upon Photothrombotic Lesion - Fiebig, Christian; Keiner, Silke; Ebert, Birgit; Schäffner, Iris; Jagasia, Ravi; Lie, Dieter Chichung; Beckervordersandforth, Ruth (Frontiers in Molecular Neuroscience, 2019)
Mitochondria are key organelles in regulating the metabolic state of a cell. In the brain, mitochondrial oxidative metabolism is the prevailing mechanism for neurons to generate ATP. While it is firmly established that neuronal function is highly dependent on mitochondrial metabolism, it is less well-understood how astrocytes function rely on mitochondria. In this study, we investigate if astrocytes require a functional mitochondrial electron transport chain (ETC) and oxidative phosphorylation (oxPhos) under physiological and injury conditions. By immunohistochemistry we show that astrocytes expressed components of the ETC and oxPhos complexes in vivo. Genetic inhibition of mitochondrial transcription by conditional deletion of mitochondrial transcription factor A (Tfam) led to dysfunctional ETC and oxPhos activity, as indicated by aberrant mitochondrial swelling in astrocytes. Mitochondrial dysfunction did not impair survival of astrocytes, but caused a reactive gliosis in the cortex under physiological conditions. Photochemically initiated thrombosis induced ischemic stroke led to formation of hyperfused mitochondrial networks in reactive astrocytes of the perilesional area. Importantly, mitochondrial dysfunction significantly reduced the generation of new astrocytes and increased neuronal cell death in the perilesional area. These results indicate that astrocytes require a functional ETC and oxPhos machinery for proliferation and neuroprotection under injury conditions.
CRIS-Team WoS Importer:2019-03-06

Mitochondria modify exercise-induced development of stem cell-derived neurons in the adult brain - Steib, Kathrin; Schäffner, Iris; Jagasia, Ravi; Ebert, Birgit; Lie, Dieter Chichung (The Journal of Neuroscience, 2014)
Neural stem cells in the adult mammalian hippocampus continuously generate new functional neurons, which modify the hippocampal network and significantly contribute to cognitive processes and mood regulation. Here, we show that the development of new neurons from stem cells in adult mice is paralleled by extensive changes to mitochondrial mass, distribution, and shape. Moreover, exercise-a strong modifier of adult hippocampal neurogenesis-accelerates neuronal maturation and induces a profound increase in mitochondrial content and the presence of mitochondria in dendritic segments. Genetic inhibition of the activity of the mitochondrial fission factor dynamin-related protein 1 (Drp1) inhibits neurogenesis under basal and exercise conditions. Conversely, enhanced Drp1 activity furthers exercise-induced acceleration of neuronal maturation. Collectively, these results indicate that adult hippocampal neurogenesis requires adaptation of the mitochondrial compartment and suggest that mitochondria are targets for enhancing neurogenesis-dependent hippocampal plasticity.
EVALuna2:26325

Model-based genotype-phenotype mapping used to investigate gene signatures of immune sensitivity and resistance in melanoma micrometastasis - Santos Rosales, Guido; Nikolov, Svetoslav; Lai, Xin; Eberhardt, Martin; Dreyer, Florian; Paul, Sushmita; Schuler, Gerold; Vera, Julio (Scientific Reports, 2016)
In this paper, we combine kinetic modelling and patient gene expression data analysis to elucidate biological mechanisms by which melanoma becomes resistant to the immune system and to immunotherapy. To this end, we systematically perturbed the parameters in a kinetic model and performed a mathematical analysis of their impact, thereby obtaining signatures associated with the emergence of phenotypes of melanoma immune sensitivity and resistance. Our phenotypic signatures were compared with published clinical data on pretreatment tumor gene expression in patients subjected to immunotherapy against metastatic melanoma. To this end, the differentially expressed genes were annotated with standard gene ontology terms and aggregated into metagenes. Our method sheds light on putative mechanisms by which melanoma may develop immunoresistance. Precisely, our results and the clinical data point to the existence of a signature of intermediate expression levels for genes related to antigen presentation that constitutes an intriguing resistance mechanism, whereby micrometastases are able to minimize the combined anti-tumor activity of complementary responses mediated by cytotoxic T cells and natural killer cells, respectively. Finally, we computationally explored the efficacy of cytokines used as low-dose co-adjuvants for the therapeutic anticancer vaccine to overcome tumor immunoresistance.
EVALuna2:19575

Modifying microRNAs–another piece of the melanoma puzzle - Dietrich, Peter; Boßerhoff, Anja Katrin (Pigment Cell & Melanoma Research, 2015)
EVALuna2:4718

Modulation of Recombinant Human ?1 Glycine Receptors by Mono- and Disaccharides: A Kinetic Study - Breitinger, Ulrike; Sticht, Heinrich; Breitinger, Hans-Georg (Acs Chemical Neuroscience, 2016)
Glycine receptors (GlyRs) mediate fast synaptic inhibition in spinal cord, brainstem, and higher brain centers. Recently, glucose was identified as a positive modulator of GlyR-mediated currents. Here, we investigated extent and kinetics of the positive modulation of recombinant human ?1 glycine receptors by different mono- and disaccharides and sorbitol using patch-clamp recording techniques. Glucose and fructose augmented glycine-mediated whole-cell currents with an EC50 of 6-7 mM. At concentrations > 10 mM, the maximum of current enhancement was reached within 30 min. Kinetics of GlyR modulation resemble those of protein glycation. On-rates were <0.5 h for saturating concentrations of monosaccharides and 1.5 h for disaccharides. Off-rates were considerably slower (>24 h). Galactose, the C4-epimer of glucose, and the sugar alcohol sorbitol had no effect on GlyR currents. Recent cryoelectron microscopy structures were used to identify a potential binding site for saccharides near the ivermectin binding pocket with lysine 143 as possible attachment site. The GlyR mutant ?1(K143A) was not potentiated by glucose, suggesting an involvement of this residue in glycine receptor modulation by saccharides.
EVALuna2:26302

Modulation of recombinant human alpha 1 glycine receptor by flavonoids and gingerols - Breitinger, Ulrike; Sticht, Heinrich; Breitinger, Hans Georg (Biological Chemistry, 2021)
The inhibitory glycine receptor (GlyR) is a principal mediator of fast synaptic inhibition in mammalian spinal cord, brainstem, and higher brain centres. Flavonoids are secondary plant metabolites that exhibit many beneficial physiological effects, including modulatory action on neuronal receptors. Using whole-cell current recordings from recombinant human α1 GlyRs, expressed in HEK293 cells, we compared the flavonols kaempferol and quercetin, the flavanone naringenin, the flavones apigenin and nobiletin, the isoflavone genistein, and two gingerols, 6-gingerol and 8-gingerol for their modulation of receptor currents. All compounds were inhibitors of the GlyR with IC50values ranging between 9.3 ± 2.6 μM (kaempferol) and 46.7 ± 6.5 μM (genistein), following a mixed mode of inhibition. Co-application of two inhibitors revealed distinct binding sites for flavonoids and gingerols. Pore-lining mutants T258A and T258S were strongly inhibited by quercetin and naringenin, but not by 6-gingerol, confirming the existence of distinct binding sites for flavonoids and gingerols. Apigenin, kaempferol, nobiletin, naringenin and 6-gingerol showed biphasic action, potentiating glycineinduced currents at low concentration of both, modulator and glycine, and inhibiting at higher concentrations. Identification of distinct modulatory sites for flavonoids and related compounds may present pharmacological target sites and aid the discovery of novel glycinergic drugs.
CRIS-Team Scopus Importer:2021-04-09
Keywords: Inhibition; Ion channels; Plant metabolites; Potentiation; Receptor modulation; Synaptic receptors

Modulation of TTX-sensitive voltage-dependent Na+ channels by ?-bungarotoxin in rat cerebellar neurons - Guo, Da; Xiang, Wei; Seebahn, Angela; Becker, Cord-Michael; Strauss, Olaf (BMC Neuroscience, 2012)
The modulation of voltage-dependent Na+ channels by lipid metabolites such as arachidonic acid or eicosanoids plays a role in physiological functions as well as in degenerative diseases. So far TTX-resistant channels were found mainly to be regulated by lipid metabolites.We investigated the lipid-dependent modulation of TTX-sensitive (TTX-s) Na+ channels using ?-bungarotoxin (?-BuTX, 10 pM), which has an intrinsic phospholipase-A2 activity, and indomethacin (10 ?M), which blocks cyclooxygenase activity in primary cerebellar neurons. To investigate TTX-s Na+ channels, whole-currents were measured under K+-free conditions and blocked by 10 nM TTX. The currents resulting from calculating the difference of currents measured in the presence and the absence of TTX were used for further analysis. Application of indomethacin mainly changed the current kinetics but has only minor effects on voltage-dependence. In contrast ?-BuTX increased the maximal current amplitude and shifted the voltage-dependent activation towards more negative potentials. The effects of ?-BuTX were blocked by indomethacin. Analysis of lipid metabolites which accumulate by treatment with ?-BuTX using MALDI-TOF MS showed an increase of cyclooxygenase reaction products in relation to arachidonic acid.In summary, we conclude that TTX-sensitive Na+ channels can be directly modulated by cyclooxygenase reaction products leading to higher activity at less depolarized potentials and subsequent higher excitability of neurons. Since activation of cyclooxygenase is also involved in pathways leading to apoptotic cells death this could play a role in degenerative diseases of the CNS and highlights a possible protective effect of cyclooxygenase inhibition.
EVALuna2:4677

Molecular analysis of tumor dormancy of the malignant 3D printed model of melanoma - Schmidt, Sarah; Fischer, S.; Schmid, R.; Arkudas, Andreas; Kengel-Bach-Weigand, A.; Kappelmann-Fenzl, M.; Boßerhoff, Anja Katrin (JOURNAL DER DEUTSCHEN DERMATOLOGISCHEN GESELLSCHAFT, 2022)
CRIS-Team WoS Importer:2022-09-23

Molecular changes induced in melanoma by cell culturing in 3D alginate hydrogels - Kappelmann-Fenzl, M.; Schmidt, Sonja; Fischer, Stefan; Schmid, Rafael; Lämmerhirt, Lisa; Fischer, Lena; Schrüfer, Stefan; Thievessen, Ingo; Schubert, Dirk W.; Matthies, Alexander Oliver; Detsch, Rainer; Boccaccini, Aldo R.; et al. (Cancers, 2021)
Alginate hydrogels have been used as a biomaterial for 3D culturing for several years. Here, gene expression patterns in melanoma cells cultivated in 3D alginate are compared to 2D cultures. It is well-known that 2D cell culture is not resembling the complex in vivo situation well. However, the use of very intricate 3D models does not allow performing high-throughput screening and analysis is highly complex. 3D cell culture strategies in hydrogels will better mimic the in vivo situation while they maintain feasibility for large-scale analysis. As alginate is an easy-to-use material and due to its favorable properties, it is commonly applied as a bioink component in the growing field of cell encapsulation and biofabrication. Yet, only a little information about the transcriptome in 3D cultures in hydrogels like alginate is available. In this study, changes in the transcriptome based on RNA-Seq data by cultivating melanoma cells in 3D alginate are analyzed and reveal marked changes compared to cells cultured on usual 2D tissue culture plastic. Deregulated genes represent valuable cues to signaling pathways and molecules affected by the culture method. Using this as a model system for tumor cell plasticity and heterogeneity, EGR1 is determined to play an important role in melanoma progression.
CRIS-Team Scopus Importer:2021-08-20
Keywords: 3D cultivation; Biomaterials; EGR1; Melanoma; Whole transcriptome

Molecular cross-talk between Y5-receptor and neuropeptide Y drives liver cancer - Dietrich, Peter; Wormser, Laura; Fritz, Valerie; Seitz, Tatjana; de Maria, Monica; Schambony, Alexandra; Kremer, Andreas; Günther, Claudia; Itzel, Timo; Thasler, Wolfgang E.; Teufel, Andreas; Trebicka, Jonel; et al. (Journal of Clinical Investigation, 2020)
Hepatocellular carcinoma (HCC) is clearly age-related and represents one of the deadliest cancer types worldwide. Due to globally increasing risk factors including metabolic disorders, the incidence rates of HCC are still rising. However, the molecular hallmarks of HCC remain poorly understood. Neuropeptide Y (NPY) and NPY-receptors represent a highly conserved, stress-activated system which is involved in diverse cancer-related hallmarks including aging and metabolic alterations, but its impact on liver cancer had been unclear. Here, we observed increased NPY5-receptor (Y5R) expression in HCC which correlated with tumor growth and survival. Furthermore, we found that its ligand NPY was secreted by peri-tumorous hepatocytes. Hepatocyte-derived NPY promoted HCC progression by Y5R-activation. Transforming growth factor beta 1 (TGFβ1) was identified as a regulator of NPY in hepatocytes and induced Y5R in invasive cancer cells. Moreover, NPY-conversion by dipeptidylpeptidase 4 (DPP4) augmented Y5R-activation and function in liver cancer. The TGFβ-NPY-Y5R-axis and DPP4 represent attractive therapeutic targets for controlling liver cancer progression.
EVALuna2:212290
Keywords: Aging; Cancer; Hepatology

Molecular dynamics simulation links conformation of a pore-flanking region to hyperekplexia-related dysfunction of the inhibitory glycine receptor - Breitinger, Hans-Georg Albrecht; Lanig, Harald; Breitinger, Ulrike; Clark, Timothy; et al. (Chemistry & Biology, 2004)
Inhibitory glycine receptors mediate rapid synaptic inhibition in mammalian spinal cord and brainstem. The previously identified hyperekplexia mutation GLRA I(P250T), located within the intracellular TM1-2 loop of the GlyR alpha1 subunit, results in altered receptor activation and desensitization. Here, elementary steps of ion channel function of alpha1(250) mutants were resolved and shown to correlate with hydropathy and molar volume of residue alpha1 (250). Single-channel recordings and rapid activation kinetic studies using laser pulse photolysis showed reduced conductance but similar open probability of alpha1 (P250T) mutant channels. Molecular dynamics simulation of a helix-turn-helix motif representing the intracellular TM1-2 domain revealed alterations in backbone conformation, indicating an increased flexibility in these mutants that paralleled changes in elementary steps of channel function. Thus, the architecture of the TM1-2 loop is a critical determinant of ion channel conductance and receptor desensitization.

Molecular mechanism for distinct neurological phenotypes conveyed by allelic truncating mutations. - Wegner, Michael; et al. (Nature Genetics, 2004)
The molecular mechanisms by which different mutations in the same gene can result in distinct disease phenotypes remain largely unknown. Truncating mutations of SOX10 cause either a complex neurocristopathy designated PCWH or a more restricted phenotype known as Waardenburg-Shah syndrome (WS4; OMIM 277580). Here we report that although all nonsense and frameshift mutations that cause premature termination of translation generate truncated SOX10 proteins with potent dominant-negative activity, the more severe disease phenotype, PCWH, is realized only when the mutant mRNAs escape the nonsense-mediated decay (NMD) pathway. We observe similar results for truncating mutations of MPZ that convey distinct myelinopathies. Our experiments show that triggering NMD and escaping NMD may cause distinct neurological phenotypes.
UnivIS-Import:2015-03-09:Pub.2004.med.IB.LPCIPDBI.molecu

Molecular mechanism of HIV-1 gp120 mutations that reduce CD4 binding affinity - Kaßler, Kristin; Sticht, Heinrich (Journal of Biomolecular Structure & Dynamics, 2014)
The interaction of the HIV-1 fusion protein gp120 with its cellular receptor CD4 represents a crucial step of the viral infection process, thus rendering gp120 a promising target for the intervention with anti-HIV drugs. Naturally occurring mutations of gp120, however, can decrease its affinity for anti-infective ligands like therapeutic antibodies or soluble CD4. To understand this phenomenon on a structural level, we performed molecular dynamics simulations of two gp120 variants (termed gp1203-2 and gp1202-1), which exhibit a significantly decreased binding of soluble CD4. In both variants, the exchange of a nonpolar residue by glutamate was identified as an important determinant for reduced binding. However, those glutamates are located at different sequence positions and affect different steps of the recognition process: E471 in gp1203-2 predominantly affects the CD4-bound conformation, whereas E372 in gp1202-1 mainly modulates the conformational sampling of free gp120. Despite these differences, there exists an interesting similarity between the two variants: both glutamates exert their function by modulating the conformation and interactions of glycine-rich motifs (G366-G367, G471-G473) resulting in an accumulation of binding incompetent gp120 conformations or a loss of intermolecular gp120-CD4 hydrogen bonds. Thus, the present data suggests that interference with the structure and dynamics of glycine-rich stretches might represent a more widespread mechanism, by which gp120 mutations reduce binding affinity. This knowledge should be helpful to predict the resistance of novel gp120 mutations or to design gp120-ligands with improved binding properties. An animated interactive 3D complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal:JBSD:41.
EVALuna2:26280

Molecular mechanisms of OIS breakdown in the context of melanoma formation - Kluge, Viola; Zimmermann, Tom; Pommer, Michaela; Kuphal, Silke; Boßerhoff, Anja Katrin (JOURNAL DER DEUTSCHEN DERMATOLOGISCHEN GESELLSCHAFT, 2022)
CRIS-Team WoS Importer:2022-09-23

Molecular Simulations and Alzheimer׳s Disease - Söldner, Christian; Sticht, Heinrich; Horn, Anselm (Systems Medicine: Integrative, qualitative, and computational approaches, 2021)
Alzheimer׳s Disease (AD) is a progressive neurodegenerative disorder that represents a major threat to public health. A key player in AD is the short peptide Amyloid-β (Aβ), which forms soluble oligomers, structured filaments and fibrils, and finally plaques in patients’ brains. A rational design of anti-aggregation drugs requires knowledge of the target molecular structure, which is difficult to be obtained by experimental methods due to the multitude of Aβ aggregation states and conformations. In this context, computer simulation methods like molecular dynamics (MD) simulations offer a valuable supplement. The present article gives a brief introduction into the structure of Aβ aggregates and the principles of MD simulations. The application of MD simulations in AD is illustrated by several sample cases from the authors’ research area, in which MD simulations are used to assess the effects of various intrinsic and extrinsic factors on the conformational stability of Aβ aggregates. In particular, the role of the following factors on Aβ structure are discussed (i) influence of aggregate size and topology, (ii) influence of familial and designed point mutations, (iii) role of the N- and C-terminus for fibril and oligomer stability, (iv) differential effects of the alkali metal ions Li+, Na+, and K+ (v) mechanism of small-molecule aggregation modulators. These studies demonstrate that MD simulations cannot only be used to gain a deeper mechanistic understanding of Aβ aggregation but may also support the rational design of anti-aggregation compounds.
Keywords: Alkali metal ions; Alzheimer׳s disease; Amyloid beta; Amyloidosis; Computer simulations; Fibril; Filament; Molecular dynamics simulations; Protein aggregation; Point mutation; Protein misfolding; Rational drug design

Mono-allelic deleterious variants in autosomal recessive skeletal dysplasia genes are strongly associated with idiopathic short stature - Thiel, C. T.; Hauer, Nadine; Vogl, C.; Uebe, Steffen; Sticht, Heinrich; Ekici, Arif Bülent; Kraus, Cornelia; Dörr, Helmuth-Günther; Reis, André (EUROPEAN JOURNAL OF HUMAN GENETICS, 2020)
CRIS-Team WoS Importer:2021-01-22

MRTF-A controls vessel growth and maturation by increasing the expression of CCN1 and CCN2 - Hinkel, Rabea; Trenkwalder, Teresa; Petersen, Bjoern; Husada, Wira; Gesenhues, Florian; Lee, Seungmin; Hannappel, Ewald; Bock-Marquette, Ildiko; Theisen, Daniel; Leitner, Laura; Boekstegers, Peter; Cierniewski, Czeslaw; et al. (Nature Communications, 2014)
Gradual occlusion of coronary arteries may result in reversible loss of cardiomyocyte function (hibernating myocardium), which is amenable to therapeutic neovascularization. The role of myocardin-related transcription factors (MRTFs) co-activating serum response factor (SRF) in this process is largely unknown. Here we show that forced MRTF-A expression induces CCN1 and CCN2 to promote capillary proliferation and pericyte recruitment, respectively. We demonstrate that, upon G-actin binding, thymosin ß4 (Tß4), induces MRTF translocation to the nucleus, SRF-activation and CCN1/2 transcription. In a murine ischaemic hindlimb model, MRTF-A or Tß4 promotes neovascularization, whereas loss of MRTF-A/B or CCN1-function abrogates the Tß4 effect. We further show that, in ischaemic rabbit hindlimbs, MRTF-A as well as Tß4 induce functional neovascularization, and that this process is inhibited by angiopoietin-2, which antagonizes pericyte recruitment. Moreover, MRTF-A improves contractile function of chronic hibernating myocardium of pigs to a level comparable to that of transgenic pigs overexpressing Tß4 (Tß4tg). We conclude that MRTF-A promotes microvessel growth (via CCN1) and maturation (via CCN2), thereby enabling functional improvement of ischaemic muscle tissue.
EVALuna2:4969

Multifrequency Investigation of Single-and Double-Stranded DNA with Scalable Metamaterial-Based THz Biosensors - Weisenstein, Christian; Richter, Merle; Wigger, Anna Katharina; Boßerhoff, Anja Katrin; Bolivar, Peter Haring (Biosensors, 2022)
Due to the occurrence of THz-excited vibrational modes in biomacromolecules, the THz frequency range has been identified as particularly suitable for developing and applying new bio-analytical methods. We present a scalable THz metamaterial-based biosensor being utilized for the multifrequency investigation of single-and double-stranded DNA (ssDNA and dsDNA) samples. It is demonstrated that the metamaterial resonance frequency shift by the DNA’s presence depends on frequency. Our experiments with the scalable THz biosensors demonstrate a major change in the degree of the power function for dsDNA by 1.53 ± 0.06 and, in comparison, 0.34 ± 0.11 for ssDNA as a function of metamaterial resonance frequency. Thus, there is a significant advantage for dsDNA detection that can be used for increased sensitivity of biomolecular detection at higher frequencies. This work represents a first step for application-specific biosensors with potential advantages in sensitivity, specificity, and robustness.
CRIS-Team Scopus Importer:2022-08-05
Keywords: biomolecular; biomolecules; biosensor; DNA; FSS; metamaterial; sensitivity; sensor; terahertz; THz

Multiple conserved regulatory elements with overlapping functions determine Sox10 expression in mouse embryogenesis. - Wegner, Michael; et al. (Nucleic Acids Research, 2007)
Expression and function of the transcription factor Sox10 is predominant in neural crest cells, its derivatives and in oligodendrocytes. To understand how Sox10 expression is regulated during development, we analysed the potential of evolutionary conserved non-coding sequences in the Sox10 genomic region to function as enhancers. By linking these sequences to a β-galactosidase marker gene under the control of a minimal promoter, five regulatory regions were identified that direct marker gene expression in transgenic mice to Sox10 expressing cell types and tissues in a defined temporal pattern. These possible enhancers of the Sox10 gene mediate Sox10 expression in the otic vesicle, in oligodendrocytes and in several neural crest derivatives including the developing peripheral nervous system and the adrenal gland. They furthermore exhibit overlapping activities and share binding sites for Sox, Lef/Tcf, Pax and AP2 transcription factors. This may explain high level and robustness of Sox10 expression during embryonic development. © 2007 The Author(s).
UnivIS-Import:2015-03-09:Pub.2007.med.IB.LPCIPDBI.multip

Multiple cyclic nucleotide-gated channels coordinate calcium oscillations and polar growth of root hairs - Brost, Christa; Studtrucker, Tanja; Reimann, Ronny; Denninger, Philipp; Czekalla, Jennifer; Krebs, Melanie; Fabry, Ben; Schumacher, Karin; Grossmann, Guido; Dietrich, Petra (Plant Journal, 2019)
Calcium gradients underlie polarization in eukaryotic cells. In plants, a tip-focused Ca2+-gradient is fundamental for rapid and unidirectional cell expansion during epidermal root hair development. Here we report that three members of the cyclic nucleotide-gated channel family are required to maintain cytosolic Ca2+ oscillations and the normal growth of root hairs. CNGC6, CNGC9 and CNGC14 were expressed in root hairs, with CNGC9 displaying the highest root hair specificity. In individual channel mutants, morphological defects including root hair swelling and branching, as well as bursting, were observed. The developmental phenotypes were amplified in the three cngc double mutant combinations. Finally, cngc6/9/14 triple mutants only developed bulging trichoblasts and could not form normal root hair protrusions because they burst after the transition to the rapid growth phase. Prior to developmental defects, single and double mutants showed increasingly disturbed patterns of Ca2+ oscillations. We conclude that CNGC6, CNGC9 and CNGC14 fulfill partially but not fully redundant functions in generating and maintaining tip-focused Ca2+ oscillations, which are fundamental for proper root hair growth and polarity. Furthermore, the results suggest that these calmodulin-binding and Ca2+-permeable channels organize a robust tip-focused oscillatory calcium gradient, which is not essential for root hair initiation but is required to control the integrity of the root hair after the transition to the rapid growth phase. Our findings also show that root hairs possess a large ability to compensate calcium-signaling defects, and add new players to the regulatory network, which coordinates cell wall properties and cell expansion during polar root hair growth.
CRIS-Team Scopus Importer:2019-09-03
Keywords: Arabidopsis thaliana; calcium channel; polar growth; R-GECO1; RootChip; trichoblast

Multipole electrostatic model for MNDO-like techniques with minimal valence spd-basis sets (vol 114, pg 159, 2005) - Horn, Anselm; Lin, Jr-Hung; Clark, Timothy (Theoretical Chemistry Accounts, 2007)

Multipole electrostatic potential derived atomic charges in NDDO-methods with spd-basis sets - Horn, Anselm; Clark, Timothy (Journal of Molecular Modeling, 2007)
The recently introduced multipole approach for computing the molecular electrostatic potential (MEP) within the semiempirical neglect of diatomic differential overlap (NDDO) framework [Horn AHC, Lin Jr-H., Clark T (2005) Theor Chem Acc 114:159-168] has been used to obtain atomic charges of nearly ab initio quality by scaling the semiempirical MEP. The parameterization set comprised a total of 797 compounds and included not only the newly parameterized AM1* elements Al, Si, P, S, Cl, Ti, Zr, and Mo but also the standard AM1 elements H, C, N, O and F. For comparison, the ZDO-approximated MEP was also calculated analytically in the spd-basis. For the AM1*-optimized structures, single-point calculations at the B3LYP, HF and MP2 levels with the 6-31G(d) and LanL2DZP basis sets were performed to obtain the MEP. The regression analysis of all 12 combinations of semiempirical and ab initio MEP data yielded correlation coefficients of at least 0.99 in all cases. Scaling the analytical and multipole-derived semiempirical MEP by the regression coefficients yielded mean unsigned errors below 2.6 and 1.9 kcal mol(-1), respectively. Subsequently, for 22 drug molecules from the World Drug Index, atomic charges were computed according to the RESP procedure using XX/6-31G(d) (XX=B3LYP, HF, MP2) and scaled AM1* multipole MEP; the correlation coefficients obtained are 0.83, 0.85 and 0.83, respectively. Figure: Schematic representation of the atomic charge generation: The molecular electrostatic potential (MEP) is calculated using the AM1* Hamiltonian; then the semiempirical MEP is scaled to DFT or ab initio level, and atomic charges are generated subsequently by the restraint electrostatic potential (RESP) fit method.
Keywords: AM1*; semiempirical MO theory; atomic charges; molecular electrostatic potential; multipole

Muscarinic acetylcholine receptors activate expression of the EGr gene family of transcription factors - Wegner, Michael; et al. (Journal of Biological Chemistry, 1998)
In order to search for genes that are activated by muscarinic acetylcholine receptors (mAChRs), we used an mRNA differential display approach in HEK293 cells expressing m1AChR. The zinc-finger transcription factor genes Egr-1, Egr-2, and Egr-3 were identified. Northern blot analyses confirmed that mRNA levels of Egr-1, Egr-2, and Egr-3 increased readily after mAChR stimulation and that a maximum was attained within 50 min. At that time, Egr-4 mRNA was also detectable. Western blots and electromobility shift assays demonstrated synthesis of EGR-1 and EGR-3, as well as binding to DNA recognition sites in response to m1AChR activation. Activation of m1AChR increased transcription from EGR-dependent promoters, including the acetylcholinesterase gene promoter. Activity-dependent regulation of Egr-1 mRNA expression and EGR-1 protein synthesis was also observed in cells expressing m2, m3, or m4AChR subtypes. Increased EGR-1 synthesis was mimicked by phorbol myristate acetate, but not by forskolin, and receptor-stimulated EGR-1 synthesis was partially inhibited by phorbol myristate acetate down- regulation. Together, our results demonstrate that muscarinic receptor signaling activates the EGR transcription factor family and that PKC may be involved in intracellular signaling. The data suggest that transcription of EGR-dependent target genes, including the AChE gene, can be under the control of extracellular and intracellular signals coupled to muscarinic receptors.
UnivIS-Import:2015-03-05:Pub.1998.med.IB.LPCIPDBI.muscar_10

Muscarinic acetylcholine receptors activate the acetylcholinesterase gene promoter - Wegner, Michael; et al. (Journal of Physiology-Paris, 1998)
The acetylcholinesterase (AChE) gene promoter contains several overlapping binding sites for Sp1 and Egr-1 transcription factors. Cotransfection experiments and promoter assays showed that Egr-1 can potently activate transcription from the human AChE promoter. Muscarinic acetylcholine receptors (mAChR) rapidly activate, via protein kinase C-mediated signaling, expression of the Egr-1 gene, leading to dramatically increased nuclear concentrations of Egr-1 protein, and to increased binding of Egr-1 to specific DNA recognition sequences. These mAChR-induced increases are followed by increased transcription from the human AChE promoter. In vivo studies with intraventricular infusions of the cholinergic immunotoxin 192 IgG saporin showed more than 80% decrease of AChE activity in cholinergic target areas of the hippocampus and brain cortex. The results are compatible with a combination of decreased AChE activity in degenerating subcortical cholinergic projections, and additional decreases in postsynaptic AChE gene expression. Together our data show that mAChR can activate transcription from the AChE promoter via increased synthesis of Egr-1. The results suggest a feedback mechanism by which the AChE gene is activated by cholinergic neurotransmission, possibly leading to increased formation of AChE protein and accelerated degradation of acetylcholine at cholinergic synapses. This possibility suggests testing of cholinomimetic compounds currently in development for the treatment of Alzheimer's disease for their potential ability to increase AChE gene expression.
UnivIS-Import:2015-03-05:Pub.1998.med.IB.LPCIPDBI.muscar

Mutation of the Sry-related Sox10 gene in Dominat megacolon, a mouse model for human Hirschsprung disease - Wegner, Michael; et al. (Proceedings of the National Academy of Sciences of the United States of America, 1998)
UnivIS-Import:2015-03-05:Pub.1998.med.IB.LPCIPDBI.mutati

Mutations in DCPS and EDC3 in autosomal recessive intellectual disability indicate a crucial role for mRNA decapping in neurodevelopment - Ahmed, Iltaf; Buchert, Rebecca; Zhou, Mi; Jiao, Xinfu; Mittal, Kirti; Sheikh, Taimoor I.; Scheller, Ute; Vasli, Nasim; Rafiq, Muhammad Arshad; Brohi, M. Qasim; Mikhailov, Anna; Ayaz, Muhammad; et al. (Human Molecular Genetics, 2015)
There are two known mRNA degradation pathways, 3' to 5' and 5' to 3'. We identified likely pathogenic variants in two genes involved in these two pathways in individuals with intellectual disability. In a large family with multiple branches, we identified biallelic variants in DCPS in three affected individuals; a splice site variant (c.636+1G>A) that results in an in-frame insertion of 45 nucleotides and a missense variant (c.947C>T; p.Thr316Met). DCPS decaps the cap structure generated by 3' to 5' exonucleolytic degradation of mRNA. In vitro decapping assays showed an ablation of decapping function for both variants in DCPS. In another family, we identified a homozygous mutation (c.161T>C; p.Phe54Ser) in EDC3 in two affected children. EDC3 stimulates DCP2, which decaps mRNAs at the beginning of the 5' to 3' degradation pathway. In vitro decapping assays showed that altered EDC3 is unable to enhance DCP2 decapping at low concentrations and even inhibits DCP2 decapping at high concentration. We show that individuals with biallelic mutations in these genes of seemingly central functions are viable and that these possibly lead to impairment of neurological functions linking mRNA decapping to normal cognition. Our results further affirm an emerging theme linking aberrant mRNA metabolism to neurological defects.
EVALuna2:9274

Mutations in herpes simplex virus gD protein affect receptor binding by different molecular mechanisms - Stump, Joachim; Sticht, Heinrich (Journal of Molecular Modeling, 2014)
Glycoprotein D (gD) is an essential protein of herpes simplex virus-1 (HSV-1) that targets the structurally unrelated receptors HVEM and nectin-1. Receptor binding of gD is accompanied by intramolecular structural rearrangements including the detachment of the C-terminus or formation of an N-terminal hairpin structure. We have investigated several gD mutations that were reported to affect receptor binding affinity or specificity in order to identify their molecular mode of action. Molecular dynamics simulations and subsequent energetic analyses of the gD-receptor complexes reveal that some mutations (M11A, N15A, L28A, T29A) play a more prominent role for HVEM binding than for nectin-1 binding, thereby conferring specificity to receptor recognition. However, our studies show that mutations can also affect the intramolecular structural rearrangement processes in gD. W294A and Q27A mutations facilitate the detachment of the C-terminus, and Q27A additionally hampers the formation of an intramolecular hairpin in gD that is exclusively established upon HVEM binding. The finding that a Q27A mutation affects multiple steps of the receptor binding process offers a molecular explanation for its enhanced nectin-1 affinity and the pronounced receptor specificity. This study also indicates that an inspection of the gD-receptor interfaces alone may be insufficient for predicting the effect of novel mutations that alter receptor specificity. Instead, such an analysis will additionally require to assess the effect of candidate mutation on the preceding steps of gD activation.
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Mutations in IL36RN in patients with generalized pustular psoriasis - Koerber, Andreas; Moessner, Rotraut; Renner, Regina; Sticht, Heinrich; Wilsmann-Theis, Dagmar; Schulz, Peter; Sticherling, Michael; Traupe, Heiko; Hüffmeier, Ulrike (Journal of Investigative Dermatology, 2013)
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Mutations in the B.1.1.7 SARS-CoV-2 Spike Protein Reduce Receptor-Binding Affinity and Induce a Flexible Link to the Fusion Peptide - Socher, Eileen; Conrad, Marcus; Heger, Lukas; Paulsen, Friedrich; Sticht, Heinrich; Zunke, Friederike; Arnold, Philipp (Biomedicines, 2021)
The B.1.1.7 variant of the SARS-CoV-2 virus shows enhanced infectiousness over the wild type virus, leading to increasing patient numbers in affected areas. Amino acid exchanges within the SARS-CoV-2 spike protein variant of B.1.1.7 affect inter-monomeric contact sites within the trimer (A570D and D614G) as well as the ACE2-receptor interface region (N501Y), which comprises the receptor-binding domain (RBD) of the spike protein. However, the molecular consequences of mutations within B.1.1.7 on spike protein dynamics and stability or ACE2 binding are largely unknown. Here, molecular dynamics simulations comparing SARS-CoV-2 wild type with the B.1.1.7 variant revealed inter-trimeric contact rearrangements, altering the structural flexibility within the spike protein trimer. Furthermore, we found increased flexibility in direct spatial proximity of the fusion peptide due to salt bridge rearrangements induced by the D614G mutation in B.1.1.7. This study also implies a reduced binding affinity for B.1.1.7 with ACE2, as the N501Y mutation restructures the RBD-ACE2 interface, significantly decreasing the linear interaction energy between the RBD and ACE2. Our results demonstrate how mutations found within B.1.1.7 enlarge the flexibility around the fusion peptide and change the RBD-ACE2 interface. We anticipate our findings to be starting points for in depth biochemical and cell biological analyses of B.1.1.7.
CRIS-Team WoS Importer:2021-06-04
Keywords: COVID-19; SARS-CoV-2; B.1.1.7; molecular dynamics simulation; ACE2; receptor binding

Mutual antagonism between Sox10 and NFIA regulates diversification of glial lineages and glioma subtypes - Glasgow, Stacey M.; Zhu, Wenyi; Stolt, Claus; Huang, Teng-Wei; Chen, Fuyi; Loturco, Joseph J.; Neul, Jeffrey L.; Wegner, Michael; Mohila, Carrie; Deneen, Benjamin (Nature Neuroscience, 2014)
Lineage progression and diversification is regulated by the coordinated action of unique sets of transcription factors. Oligodendrocytes (OL) and astrocytes (AS) comprise the glial sub-lineages in the CNS, and the manner in which their associated regulatory factors orchestrate lineage diversification during development and disease remains an open question. Sox10 and NFIA are key transcriptional regulators of gliogenesis associated with OL and AS. We found that NFIA inhibited Sox10 induction of OL differentiation through direct association and antagonism of its function. Conversely, we found that Sox10 antagonized NFIA function and suppressed AS differentiation in mouse and chick systems. Using this developmental paradigm as a model for glioma, we found that this relationship similarly regulated the generation of glioma subtypes. Our results describe the antagonistic relationship between Sox10 and NFIA that regulates the balance of OL and AS fate during development and demonstrate for the first time, to the best of our knowledge, that the transcriptional processes governing glial sub-lineage diversification oversee the generation of glioma subtypes.
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Mutual Antagonism Between Sox10 and NFIA Regulates Diversification of Glial Lineages and Glioma Sub-Types. - Wegner, Michael; et al. (Nature Neuroscience, 2014)
UnivIS-Import:2018-09-05:Pub.2014.med.IB.LPCIPDBI.mutual

Myelin Proteolipid Protein (PLP) as a Marker Antigen of Central Nervous System Contaminations for Routine Food Control - Villmann, Carmen; Sandmeier, Barbara; Seeber, Silke; Hannappel, Ewald; Pischetsrieder, Monika; Becker, Cord-Michael (Journal of Agricultural and Food Chemistry, 2007)
Spreading transmissible spongiform encephalopathies (TSE) have been widely attributed to transmission by ingestion of mammalian central nervous system (CNS) tissue. Reliable exclusion of this epidemiological important route of transmission relies on an effective surveillance of food contamination. Here, myelin proteolipid protein (PLP) is identified as a specific and largely heat-resistant marker for detection of food contaminations by CNS tissue. PLP is a component of oligodendritic glial sheaths of neuronal processes that is specifically expressed in the CNS. A highly selective polyclonal antibody was developed directed against an epitope present in the full-length PLP protein, but absent from the developmentally regulated splice variant DM-20. In combination with a hydrophobic extraction of PLP from tissue samples, the antibody reliably detected PLP from spinal cord, cerebellum, and cortex of different mammalian species. Consistent with earlier reports on PLP expression, no cross-reactivity was observed with peripheral nerve or extraneural tissue, except for a very faint signal obtained with heart. When applied to an artificial CNS contamination present in sausages, the antibody reliably detected a low concentration (1%) of the contaminant. Application of heat, as used during conventional sausage manufacturing, led to a predominant alteration of arginine residues in the PLP protein and a partial loss of immunoreactivity. In contrast, a stretch of hydrophilic amino acids112-122 proved to be heat-resistant, preserving the immunogenicity of this PLP epitope during heating. Taken together, the excellent CNS specificity of PLP immunodetection and the presence of a heat-resistant epitope have permitted the development of a highly sensitive immunoassay for CNS contamination in routine food control. © 2007 American Chemical Society.
UnivIS-Import:2015-04-14:Pub.2007.nat.dchph.llmch.myelin
Keywords: CNS; Food contamination; Myelin proteolipid protein; Polyclonal antibody

Myelin Regulatory Factor 1 Drives Remyelination in Multiple Sclerosis. - Duncan, Greg J.; Plemel, Jason R.; Assinck, Peggy; Manesh, Sohrab B.; Muir, Fraser G. W.; Hirata, Ryan; Berson, Matan; Liu, Jie; Wegner, Michael; Emery, Ben; Moore, G. R. Wayne; Tetzlaff, Wolfram (Acta Neuropathologica, 2017)
UnivIS-Import:2018-09-05:Pub.2017.med.IB.LPCIPDBI.myelin

Myeloperoxidase Modulates Inflammation in Generalized Pustular Psoriasis and Additional Rare Pustular Skin Diseases - Haskamp, Stefan; Bruns, Heiko; Hahn, Madelaine; Hoffmann, Markus; Gregor, Anne; Löhr, Sabine; Hahn, Jonas; Ringer, Mark; Flamann, Cindy; Frey, Benjamin; Lesner, Adam; Thiel, Christian; et al. (American Journal of Human Genetics, 2020)
Generalized pustular psoriasis (GPP) is a severe multi-systemic inflammatory disease characterized by neutrophilic pustulosis and triggered by pro-inflammatory IL-36 cytokines in skin. While 19%–41% of affected individuals harbor bi-allelic mutations in IL36RN, the genetic cause is not known in most cases. To identify and characterize new pathways involved in the pathogenesis of GPP, we performed whole-exome sequencing in 31 individuals with GPP and demonstrated effects of mutations in MPO encoding the neutrophilic enzyme myeloperoxidase (MPO). We discovered eight MPO mutations resulting in MPO -deficiency in neutrophils and monocytes. MPO mutations, primarily those resulting in complete MPO deficiency, cumulatively associated with GPP (p = 1.85E−08; OR = 6.47). The number of mutant MPO alleles significantly differed between 82 affected individuals and >4,900 control subjects (p = 1.04E−09); this effect was stronger when including IL36RN mutations (1.48E−13) and correlated with a younger age of onset (p = 0.0018). The activity of four proteases, previously implicated as activating enzymes of IL-36 precursors, correlated with MPO deficiency. Phorbol-myristate-acetate-induced formation of neutrophil extracellular traps (NETs) was reduced in affected cells (p = 0.015), and phagocytosis assays in MPO-deficient mice and human cells revealed altered neutrophil function and impaired clearance of neutrophils by monocytes (efferocytosis) allowing prolonged neutrophil persistence in inflammatory skin. MPO mutations contribute significantly to GPP's pathogenesis. We implicate MPO as an inflammatory modulator in humans that regulates protease activity and NET formation and modifies efferocytosis. Our findings indicate possible implications for the application of MPO inhibitors in cardiovascular diseases. MPO and affected pathways represent attractive targets for inducing resolution of inflammation in neutrophil-mediated skin diseases.
CRIS-Team Scopus Importer:2020-09-11
Keywords: ACH; acrodermatitis continua suppurativa Hallopeau; activation of IL-36 precursors; acute generalized 4 exanthematous pustulosis; AGEP; efferocytosis; generalized pustular psoriasis; GPP; impaired NETosis; MPO deficiency; myeloperoxidase; oligogenic inheritance

Myrf as a molecular switch for target gene selection of Sox10 during oligodendroglial development - Aprato, Jessica; Küspert, Melanie; Weider, Matthias; Fröb, Franziska; Wegner, Michael (GLIA, 2019)
CRIS-Team WoS Importer:2020-01-10

Myrf guides target gene selection of transcription factor Sox10 during oligodendroglial development - Aprato, Jessica; Sock, Elisabeth; Weider, Matthias; Elsesser, Olga; Fröb, Franziska; Wegner, Michael (Nucleic Acids Research, 2020)
Oligodendrocytes generate myelin in the vertebrate central nervous system and thus ensure rapid propagation of neuronal activity. Their development is controlled by a network of transcription factors that function as determinants of cell identity or as temporally restricted stage-specific regulators. The continuously expressed Sox10 and Myrf, a factor induced during late development, are particularly important for terminal differentiation. How these factors function together mechanistically and influence each other, is not well understood. Here we show that Myrf not only cooperates with Sox10 during the induction of genes required for differentiation and myelin formation. Myrf also inhibits the activity of Sox10 on genes that are essential during earlier phases of oligodendroglial development. By characterization of the exact DNA-binding requirements of Myrf, we furthermore show that cooperative activation is a consequence of joint binding of Sox10 and Myrf to the same regulatory regions. In contrast, inhibition of Sox10-dependent gene activation occurs on genes that lack Myrf binding sites and likely involves physical interaction between Myrf and Sox10 followed by sequestration. These two opposite activities allow Myrf to redirect Sox10 from genes that it activates in oligodendrocyte precursor cells to genes that need to be induced during terminal differentiation.
CRIS-Team WoS Importer:2020-03-10

MYRF is a membrane-associated transcription factor that autoproteolytically cleaves to directly activate myelin genes - Bujalka, Helena; Koenning, Matthias; Jackson, Stacey; Perreau, Victoria M.; Pope, Bernard; Hay, Curtis M.; Mitew, Stanlislaw; Hill, Andrew F.; Lu, Q. Richard; Wegner, Michael; Srinivasan, Rajini; Svaren, John; et al. (Plos Biology, 2013)
The myelination of axons is a crucial step during vertebrate central nervous system (CNS) development, allowing for rapid and energy efficient saltatory conduction of nerve impulses. Accordingly, the differentiation of oligodendrocytes, the myelinating cells of the CNS, and their expression of myelin genes are under tight transcriptional control. We previously identified a putative transcription factor, Myelin Regulatory Factor (Myrf), as being vital for CNS myelination. Myrf is required for the generation of CNS myelination during development and also for its maintenance in the adult. It has been controversial, however, whether Myrf directly regulates transcription, with reports of a transmembrane domain and lack of nuclear localization. Here we show that Myrf is a membrane-associated transcription factor that undergoes an activating proteolytic cleavage to separate its transmembrane domain-containing C-terminal region from a nuclear-targeted N-terminal region. Unexpectedly, this cleavage event occurs via a protein domain related to the autoproteolytic intramolecular chaperone domain of the bacteriophage tail spike proteins, the first time this domain has been found to play a role in eukaryotic proteins. Using ChIP-Seq we show that the N-terminal cleavage product directly binds the enhancer regions of oligodendrocyte-specific and myelin genes. This binding occurs via a defined DNA-binding consensus sequence and strongly promotes the expression of target genes. These findings identify Myrf as a novel example of a membrane-associated transcription factor and provide a direct molecular mechanism for its regulation of oligodendrocyte differentiation and CNS myelination.
EVALuna2:4945

N(8)-acetylspermidine as a potential plasma biomarker for Snyder-Robinson syndrome identified by clinical metabolomics - Abela, Lucia; Simmons, Luke; Steindl, Katharina; Schmitt, Bernhard; Mastrangelo, Massimo; Joset, Pascal; Papuc, Mihaela; Sticht, Heinrich; Baumer, Alessandra; Crowther, Lisa M.; Mathis, Deborah; Rauch, Anita; et al. (Journal of Inherited Metabolic Disease, 2016)
Clinical metabolomics has emerged as a powerful tool to study human metabolism in health and disease. Comparative statistical analysis of untargeted metabolic profiles can reveal perturbations of metabolite levels in diseases and thus has the potential to identify novel biomarkers. Here we have applied a simultaneous genetic-metabolomic approach in twin boys with epileptic encephalopathy of unclear etiology. Clinical exome sequencing identified a novel missense mutation in the spermine synthase gene (SMS) that causes Snyder-Robinson syndrome (SRS). Untargeted plasma metabolome analysis revealed significantly elevated levels of N(8)-acetylspermidine, a precursor derivative of spermine biosynthesis, as a potential novel plasma biomarker for SRS. This result was verified in a third patient with genetically confirmed SRS. This study illustrates the potential of metabolomics as a translational technique to support exome data on a functional and clinical level.
EVALuna2:26293

Neprilysin-dependent neuropeptide Y cleavage in the liver promotes fibrosis by blocking NPY-receptor 1 - Ortiz, Cristina; Klein, Sabine; Reul, Winfried H.; Magdaleno, Fernando; Groeschl, Stefanie; Dietrich, Peter; Schierwagen, Robert; Uschner, Frank E.; Torres, Sandra; Hieber, Christoph; Meier, Caroline; Kraus, Nico; et al. (Cell Reports, 2023)
Development of liver fibrosis is paralleled by contraction of hepatic stellate cells (HSCs), the main profibrotic hepatic cells. Yet, little is known about the interplay of neprilysin (NEP) and its substrate neuropeptide Y (NPY), a potent enhancer of contraction, in liver fibrosis. We demonstrate that HSCs are the source of NEP. Importantly, NPY originates majorly from the splanchnic region and is cleaved by NEP in order to termi-nate contraction. Interestingly, NEP deficiency (Nep-/-) showed less fibrosis but portal hypertension upon liver injury in two different fibrosis models in mice. We demonstrate the incremental benefit of Nep-/-in addi-tion to AT1R blocker (ARB) or ACE inhibitors for fibrosis and portal hypertension. Finally, oral administration of Entresto, a combination of ARB and NEP inhibitor, decreased hepatic fibrosis and portal pressure in mice. These results provide a mechanistic rationale for translation of NEP-AT1R-blockade in human liver fibrosis and portal hypertension.
CRIS-Team WoS Importer:2023-03-17

Neural crest origin of perivascular mesenchyme in the adult thymus. - Stolt, Claus; Wegner, Michael; et al. (Journal of Immunology, 2008)
The endodermal epithelial thymus anlage develops in tight association with neural crest (NC)-derived mesenchyme. This epithelial-NC interaction is crucial for thymus development, but it is not known how NC supports thymus development or whether NC cells or their progeny make any significant contribution to the adult thymus. By nude mouse blastocyst complementation and by cell surface phenotype, we could previously separate thymus stroma into Foxn1-dependent epithelial cells and a Foxn1-independent mesenchymal cell population. These mesenchymal cells expressed vascular endothelial growth factor-A, and contributed to thymus vascularization. These data suggested a physical or functional association with thymic blood vessels, but the origin, location in the thymus, and function of these stromal cells remained unknown. Using a transgenic mouse expressing Cre recombinase in premigratory NC (Sox10-Cre), we have now fate-mapped the majority of these adult mesenchymal cells to a NC origin. NC-derived cells represent tightly vessel-associated pericytes that are sandwiched between endothelium and epithelium along the entire thymus vasculature. The ontogenetic, phenotypic, and positional definition of this distinct perivascular mesenchymal compartment provides a cellular basis for the role of NC in thymus development and possibly maintenance, and might be useful to address properties of the endothelial-epithelial barrier in the adult thymus. Copyright © 2008 by The American Association of Immunologists, Inc.
UnivIS-Import:2015-03-09:Pub.2008.med.IB.LPCIPDBI.neural

Neural crest origin of retinal and choroidal pericytes - Trost, Andrea; Schroedl, Falk; Lange, Simona; Rivera, Francisco J.; Tempfer, Herbert; Korntner, Stefanie; Stolt, Claus; Wegner, Michael; Bogner, Barbara; Kaser-Eichberger, Alexandra; Krefft, Karolina; Runge, Christian; et al. (Investigative Ophthalmology & Visual Science, 2013)
The origin of pericytes (PCs) has been controversially discussed and at least three different sources of PCs are proposed: a neural crest, mesodermal, or bone marrow origin. In the present study we investigated a potential neural crest origin of ocular PCs in a transgenic Rosa26-YFP-Sox10-Cre neural crest-specific reporter mouse model at different developmental stages.The Rosa26-YFP-Sox10-Cre mouse model expresses the yellow fluorescent protein (YFP) reporter in cells with an active Sox10 promoter and was here used for cell fate studies of Sox10-positive neural crest derived progeny cells. Detection of the YFP signal in combination with double and triple immunohistochemistry of chondroitin sulfate proteoglycan (NG2), platelet derived growth factor receptor ? (PDGFR?), ? smooth muscle actin (?SMA), oligodendrocyte transcription factor 2 (Olig2), and lectin was performed and analyzed by confocal microscopy.Sox10-YFP-positive cells and profiles were detected in the inner nuclear layer, the ganglionic cell layer, and the axons of the nerve fiber layer in postnatal retinas. An additional population has been identified in the retina, optic nerve, and choroid that displays strong perivascular localization. These cells were colocalized with the PC-specific markers NG2 and PDGFR? in embryonic (E14.5) as well as postnatal (P4, P12, 6-week-old) vasculature. Beside PCs, vascular smooth muscle cells (vSMCs) were also labeled by the Sox10-YFP reporter protein in all ocular tissues investigated.Since YFP-positive PCs and vSMCs are colocalized with NG2 and PDGFR?, we propose that capillary PCs and vSMCs in the retina and the optic nerve, both parts of the central nervous system, as well as in the choroid, a tissue of mesodermal origin, derive from the neural crest.
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