The bile acid receptor TGR5 activates the TRPA1 channel to induce itch in mice

Lieu T, Jayaweera G, Zhao P, Poole DP, Jensen D, Grace M, Mcintyre P, Bron R, Wilson YM, Krappitz M, Härteis S, Korbmacher C, Steinhoff MS, Nassini R, Materazzi S, Geppetti P, Corvera CU, Bunnett NW (2014)

Publication Type: Journal article

Publication year: 2014

Journal

Gastroenterology Elsevier

Publisher: WB Saunders

Book Volume: 147

Pages Range: 1417-28

Journal Issue: 6

DOI: 10.1053/j.gastro.2014.08.042

Abstract

Patients with cholestatic disease have increased systemic concentrations of bile acids (BAs) and profound pruritus. The G-protein-coupled BA receptor 1 TGR5 (encoded by GPBAR1) is expressed by primary sensory neurons; its activation induces neuronal hyperexcitability and scratching by unknown mechanisms. We investigated whether the transient receptor potential ankyrin 1 (TRPA1) is involved in BA-evoked, TGR5-dependent pruritus in mice.Co-expression of TGR5 and TRPA1 in cutaneous afferent neurons isolated from mice was analyzed by immunofluorescence, in situ hybridization, and single-cell polymerase chain reaction. TGR5-induced activation of TRPA1 was studied in in HEK293 cells, Xenopus laevis oocytes, and primary sensory neurons by measuring Ca(2+) signals. The contribution of TRPA1 to TGR5-induced release of pruritogenic neuropeptides, activation of spinal neurons, and scratching behavior were studied using TRPA1 antagonists or Trpa1(-/-) mice.TGR5 and TRPA1 protein and messenger RNA were expressed by cutaneous afferent neurons. In HEK cells, oocytes, and neurons co-expressing TGR5 and TRPA1, BAs caused TGR5-dependent activation and sensitization of TRPA1 by mechanisms that required G??, protein kinase C, and Ca(2+). Antagonists or deletion of TRPA1 prevented BA-stimulated release of the pruritogenic neuropeptides gastrin-releasing peptide and atrial natriuretic peptide B in the spinal cord. Disruption of Trpa1 in mice blocked BA-induced expression of Fos in spinal neurons and prevented BA-stimulated scratching. Spontaneous scratching was exacerbated in transgenic mice that overexpressed TRG5. Administration of a TRPA1 antagonist or the BA sequestrant colestipol, which lowered circulating levels of BAs, prevented exacerbated spontaneous scratching in TGR5 overexpressing mice.BAs induce pruritus in mice by co-activation of TGR5 and TRPA1. Antagonists of TGR5 and TRPA1, or inhibitors of the signaling mechanism by which TGR5 activates TRPA1, might be developed for treatment of cholestatic pruritus.

Authors with CRIS profile

Matteus Krappitz Lehrstuhl für Physiologie (Vegetative Physiologie) Silke Härteis Lehrstuhl für Physiologie (Vegetative Physiologie) Christoph Korbmacher Lehrstuhl für Physiologie (Vegetative Physiologie)

Involved external institutions

Monash University AU Australia (AU) Royal Melbourne Institute of Technology (RMIT) AU Australia (AU) The University of Melbourne AU Australia (AU) University of California San Francisco (UCSF) US United States (USA) (US) University College Dublin (UCD) IE Ireland (IE) Università degli Studi di Firenze / University of Florence IT Italy (IT)

How to cite

APA:

Lieu, T., Jayaweera, G., Zhao, P., Poole, D.P., Jensen, D., Grace, M.,... Bunnett, N.W. (2014). The bile acid receptor TGR5 activates the TRPA1 channel to induce itch in mice. Gastroenterology, 147(6), 1417-28. https://dx.doi.org/10.1053/j.gastro.2014.08.042

MLA:

Lieu, Tinamarie, et al. "The bile acid receptor TGR5 activates the TRPA1 channel to induce itch in mice." Gastroenterology 147.6 (2014): 1417-28.

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