Pirfenidone Suppresses Liver Fibrosis Through Inhibition of TGF-β-Associated Lipid Metabolic Remodeling in Hepatic Stellate Cells

Chronic liver injury is characterized by sustained activation of transforming growth factor-β (TGF-β) signaling within the fibrotic microenvironment, yet the contribution of TGF-β-associated metabolic remodeling to hepatic stellate cell (HSC) activation remains incompletely understood. Here, we investigated whether TGF-β signaling is associated with lipid metabolic remodeling in HSCs and whether pirfenidone (PFD) interferes with this process. We found that TGF-β1 was spatially associated with lipid accumulation in fibrotic liver tissue and that TGF-β1/2 promoted HSC proliferation. In vitro, TGF-β1/2 coordinately upregulated sterol regulatory element-binding protein 1 (SREBP1) and fatty acid synthase (FASN), accompanied by increased intracellular lipid accumulation and enhanced oleic acid (OA)-associated lipid responses. Low-dose OA further activated AKT/ERK/p70 S6K signaling in HSCs, whereas PFD attenuated these signaling events. In parallel, PFD suppressed TGF-β-associated lipid accumulation in vitro, reduced SREBP1/FASN expression in activated HSC-rich regions in vivo, and alleviated CCl4-induced liver fibrosis. Together, these findings support a model in which TGF-β-associated lipogenic remodeling contributes to HSC activation and suggest that interference with this metabolic state may represent one component of the antifibrotic action of pirfenidone.