Inhibition of heme-thiolate monooxygenase CYP1B1 prevents hepatic stellate cell activation and liver fibrosis by accumulating trehalose.

Activation of extracellular matrix–producing hepatic stellate cells (HSCs) is a key event in liver fibrogenesis. We showed that the expression of the heme-thiolate monooxygenase cytochrome P450 1B1 (CYP1B1) was elevated in human and mouse fibrotic livers and activated HSCs. Systemic or HSC-specific ablation and pharmacological inhibition of CYP1B1 attenuated HSC activation and protected male but not female mice from thioacetamide (TAA)–, carbon tetrachloride (CCl₄)–, or bile duct ligation (BDL)–induced liver fibrosis. Metabolomic analysis revealed an increase in the disaccharide trehalose in CYP1B1-deficient HSCs resulting from intestinal suppression of the trehalose-metabolizing enzyme trehalase, whose gene we found to be a target of RARα. Trehalose or its hydrolysis-resistant derivative lactotrehalose exhibited potent antifibrotic activity in vitro and in vivo by functioning as an HSC-specific autophagy inhibitor, which may account for the antifibrotic effect of CYP1B1 inhibition. Our study thus reveals an endobiotic function of CYP1B1 in liver fibrosis in males, mediated by liver-intestine cross-talk and trehalose. At the translational level, pharmacological inhibition of CYP1B1 or the use of trehalose/lactotrehalose may represent therapeutic strategies for liver fibrosis. Editor's summary: Hepatic stellate cells (HSCs) are well-known actors in liver fibrosis, and a better understanding of the factors governing their activity could open up therapeutic opportunities. Tung et al. examined the role of the cytochrome P450 analog CYP1B1 in liver fibrosis, finding that its inhibition or depletion reduced liver pathology in multiple mouse models in a sex-dependent manner. The authors tied the observed antifibrotic effect in males to HSC accumulation of trehalose as a result of inhibition of trehalase in the intestine. As a test of therapeutic potential, male mice fed trehalose or nonhydrolyzable lactotrehalose in drinking water showed reduced liver fibrogenesis, with follow-up analysis of similarly treated HSCs demonstrating reduced autophagic degradation. This study suggests that the metabolite trehalose may play a sex-specific role in liver fibrosis. —Catherine Charneski [ABSTRACT FROM AUTHOR]