title: Expression and function of the bile acid receptor TGR5 in Kupffer cells.
abstract: Kupffer cells are resident macrophages in the liver and play a central role in the hepatic response to injury. Bile acids can impair macrophage function leading to decreased cytokine release. TGR5 is a novel, membrane-bound bile acid receptor, and it has been suggested that the immunosuppressive effect of bile acids can be mediated by TGR5. However, the function of TGR5 in Kupffer cells has not been studied and a direct link between TGR5 and cytokine production in macrophages has not been established. The present study demonstrates that TGR5 is localized in the plasma membrane of isolated Kupffer cells and is responsive to bile acids. Furthermore, bile acids inhibited LPS-induced cytokine expression in Kupffer cells via TGR5-cAMP dependent pathways. TGR5-immunoreactivity in Kupffer cells was increased in rat livers following bile-duct ligation, suggesting that TGR5 may play a protective role in obstructive cholestasis preventing excessive cytokine production thereby reducing liver injury.
authors.affiliation: Clinic for Gastroenterology, Hepatology and Infectiology, Heinrich-Heine-University, Moorenstrasse 5, D-40225 Düsseldorf, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Keitel
authors.forename: Markus
authors.initials: M
authors.lastname: Donner
authors.forename: Stefanie
authors.initials: S
authors.lastname: Winandy
authors.forename: Ralf
authors.initials: R
authors.lastname: Kubitz
authors.forename: Dieter
authors.initials: D
authors.lastname: Häussinger
mesh_terms: D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism* / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D006801:Humans; D007728:Kupffer Cells / Q000737:chemistry / Q000187:drug effects / Q000276:immunology*; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
chemical_list: D001647:Bile Acids and Salts; D016207:Cytokines; C518268:Gpbar1 protein, rat; D043562:Receptors, G-Protein-Coupled