Fibrosis contributes to tissue repair, but excessive fibrosis disrupts organ function. Alagille syndrome (ALGS, caused by mutations in JAGGED1) results in liver disease and characteristic fibrosis. Here, we show that Jag1Ndr/Ndr mice, a model for ALGS, recapitulate ALGS-like fibrosis. Single-cell RNA-seq and multi-color flow cytometry of the liver revealed immature hepatocytes and paradoxically low intrahepatic T cell infiltration despite cholestasis in Jag1Ndr/Ndr mice. Thymic and splenic regulatory T cells (Tregs) were enriched and Jag1Ndr/Ndr lymphocyte immune and fibrotic capacity was tested with adoptive transfer into Rag1-/- mice, challenged with dextran sulfate sodium (DSS) or bile duct ligation (BDL). Transplanted Jag1Ndr/Ndr lymphocytes were less inflammatory with fewer activated T cells than Jag1+/+ lymphocytes in response to DSS. Cholestasis induced by BDL in Rag1-/- mice with Jag1Ndr/Ndr lymphocytes resulted in periportal Treg accumulation and three-fold less periportal fibrosis than in Rag1-/- mice with Jag1+/+ lymphocytes. Finally, the Jag1Ndr/Ndr hepatocyte expression profile and Treg overrepresentation were corroborated in patients' liver samples. Jag1-dependent hepatic and immune defects thus interact to determine the fibrotic process in ALGS.

• MeSH
• Alagille Syndrome pathology   genetics   MeSH
• Cell Differentiation * MeSH
• Hepatocytes * metabolism   pathology   MeSH
• Liver Cirrhosis * pathology   genetics   MeSH
• Humans MeSH
• Disease Models, Animal MeSH
• Mice, Inbred C57BL MeSH
• Mice, Knockout MeSH
• Mice MeSH
• Jagged-1 Protein * metabolism   genetics   MeSH
• T-Lymphocytes, Regulatory immunology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH