Interleukin-13 drives cholestasis and compositional changes in the gut microbiome in Abcb4-deficient mice by compromising bile duct barrier integrity

The Th2 cytokine IL-13 has been described to be involved in biliary epithelial injury and liver fibrosis in patients as well as in animal models. IL-13 was found to reduce tight junction-associated barrier function of bile ducts, to promote cholangiocyte hyperplasia, and thus causing biliary epithelial injury. We generated Abcb4-/-- and IL-13-/- double-knockout mice on fibrosis susceptible genetic background BALB/c. Molecular and cellular mechanisms of hepatic and ileal pathology were investigated by mRNA microarray. Depletion of IL-13 in Abcb4-/--mice resulted in a tenfold decrease of total serum bile acid concentrations at the age of 8 weeks and lead to a recovery of intrahepatic bile duct integrity. The decrease of serum bile acid in 8 week old mice went along with relative enhancement of bile acid excretion and normalization of the composition of fecal bile excretion, correction of fecal microbiome, and improved ileal integrity. Liver integrity, measured by serum ALT, was ameliorated in younger mice and strongly correlated with the concentration of serum bile acids. 52 weeks old Abcb4-/-IL-13-/--mice exhibited significantly reduced hepatic fibrosis. Microarray experiments were performed as dual-color hybridizations on Agilent mouse whole genome catalog 8x60K arrays. To compensate for dye-specific effects, a dye-reversal color-swap was applied.