ABCB4 and biliary liver cirrhosis: As observed in JNK-deficient mice, our analysis of liver tissue from human cholestatic patients, namely, primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC), revealed a similar dysregulation of BA synthesis and transport, confirming previous studies.9, 10, 11,35 CYP7A1 expression was upregulated, whereas BA transporters BSEP, MRP2, and MDR3 were markedly downregulated compared with healthy controls at the protein level.