title: Lymphocytes contribute to biliary injury and fibrosis in experimental xenobiotic-induced cholestasis.
abstract: The etiology of chronic bile duct injury and fibrosis in patients with autoimmune cholestatic liver diseases is complex, and likely involves immune cells such as lymphocytes. However, most models of biliary fibrosis are not autoimmune in nature. Biliary fibrosis can be induced experimentally by prolonged exposure of mice to the bile duct toxicant alpha-naphthylisothiocyanate (ANIT). We determined whether lymphocytes contributed to ANIT-mediated biliary hyperplasia and fibrosis in mice. Hepatic accumulation of T-lymphocytes and increased serum levels of anti-nuclear-autoantibodies were evident in wild-type mice exposed to ANIT (0.05% ANIT in chow). This occurred alongside bile duct hyperplasia and biliary fibrosis. To assess the role of lymphocytes in ANIT-induced biliary fibrosis, we utilized RAG1-/-mice, which lack T- and B-lymphocytes. ANIT-induced bile duct injury, indicated by increased serum alkaline phosphatase activity, was reduced in ANIT-exposed RAG1-/-mice compared to ANIT-exposed wild-type mice. Despite this reduction in biliary injury, ANIT-induced bile duct hyperplasia was similar in wild-type and RAG1-/-mice. However, hepatic induction of profibrogenic genes including COL1A1, ITGβ6 and TGFβ2 was markedly attenuated in ANIT-exposed RAG1-/-mice compared to ANIT-exposed wild-type mice. Peribiliary collagen deposition was also reduced in ANIT-exposed RAG1-/-mice. The results indicate that lymphocytes exacerbate bile duct injury and fibrosis in ANIT-exposed mice without impacting bile duct hyperplasia.
authors.affiliation: Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI 48824, USA; Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA; Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Nikita
authors.initials: N
authors.lastname: Joshi
authors.affiliation: Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA; Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Anna K
authors.initials: AK
authors.lastname: Kopec
authors.affiliation: Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Holly
authors.initials: H
authors.lastname: Cline-Fedewa
authors.affiliation: Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI 48824, USA; Department of Pathobiology & Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA; Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, USA. Electronic address: luyendyk@cvm.msu.edu.
authors.forename: James P
authors.initials: JP
authors.lastname: Luyendyk
mesh_terms: D000818:Animals; D001652:Bile Ducts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D002779:Cholestasis / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology; D008103:Liver Cirrhosis / Q000139:chemically induced* / Q000473:pathology; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D015262:Xenobiotics / Q000633:toxicity*
chemical_list: D015262:Xenobiotics
keywords: ANIT; Alpha-naphthylisothiocyanate; B cells; Bile duct; Biliary hyperplasia; Fibrosis; Hepatocellular necrosis; Liver; Lymphocytes; RAG1; T cells