BACKGROUND

Cholestatic liver diseases, including primary sclerosing cholangitis, are characterized by biliary fibroinflammation. TGFβ-activated cholangiocytes release signals that recruit immune cells and activate myofibroblasts, promoting inflammation and extracellular matrix (ECM) deposition. TGFβ also regulates stearoyl-CoA desaturase (SCD), an enzyme involved in lipid signaling. Yet, the role of SCD or its inhibitor, Aramchol, in biliary fibroinflammation had not been studied.

METHODS AND RESULTS

Mdr2-/- with established biliary fibrosis and 3,5-diethoxycarboncyl-1,4-dihydrocollidine (DDC) diet-fed mice were treated with Aramchol meglumine (12.5 mg/kg/day). Hepatic fibrosis was assessed by qPCR, Picrosirius red staining, immunofluorescence, and hydroxyproline content. Human H69 or murine large cholangiocyte cell lines stimulated with TGFβ, as well as PSC-derived cholangiocytes (PSC-C), were treated with Aramchol or SCD siRNA. RNA-seq, fibroinflammatory marker expression, peroxisome proliferator-activated receptor (PPAR) activity, and targeted fatty acid profiling were performed. Aramchol treatment significantly reduced hepatic ECM gene expression, inflammatory cytokines (Il6,Tnfa), collagen content, and myofibroblast activation (aSMA staining) in both mouse models. In TGFβ-stimulated H69 cells, Aramchol suppressed hepatic fibrosis pathways and enhanced PPAR signaling. Aramchol also reduced the expression of fibrotic markers, myofibroblast-activating mediators (VEGFA and PDGFB), and IL6, mirroring the effects of SCD knockdown. In PSC-C, Aramchol significantly downregulated SCD, VEGFA and IL6. Conversely, PPARα and -γ activity and fatty acid agonist, linoleic acid levels were increased in cholangiocyte cell lines.

CONCLUSIONS

Aramchol attenuates and prevents biliary fibrosis in mouse models of cholestatic liver disease by inhibiting TGFβ-induced fibroinflammatory mediators and activating PPARa/γ in cholangiocytes. These findings, combined with its favorable clinical safety profile, support the potential of Aramchol as a therapeutic candidate for PSC.