Cultured bacteria isolated from primary sclerosing cholangitis patient bile induce inflammation and cell death.

Primary sclerosing cholangitis (PSC) is a chronic liver disease characterized by inflammation and progressive fibrosis of the biliary tree. PSC pathogenesis remains poorly understood, and there are no effective therapies. Previous studies have observed associations between colonic and biliary microbiome alterations and PSC. We aimed to determine whether bacterial isolates cultured from PSC patient bile induce disease-associated phenotypes in cells, specifically cell death, epithelial permeability, inflammation, and changes in host-protective pathways. Bile was collected from PSC patients by endoscopic retrograde cholangiography and from non-PSC controls undergoing cholecystectomies. Biliary bacteria were cultured anaerobically, and 50 colonies per sample were identified by 16S sequencing. No bacteria were isolated from non-PSC controls, while bacteria were cultured from most PSC patients. The PSC bile microbiomes exhibited reduced diversity compared to the gut or oral cavity, with one or two species predominating. The effects of supernatants from seven PSC-associated bacterial isolates on cellular phenotypes were characterized using human colonic (Caco-2), hepatic (HepG2), and biliary (EGI-1) cells. Overall, PSC-associated bacteria produced factors cytotoxic to hepatic and biliary cells. An