Capsaicin regulated lipid metabolism in HepG2 via mitochondrial autophagy PINK1/Parkin pathway

Capsaicin (CAP), a major natural functional component in chili peppers, has garnered considerable attention for its health benefits, including lipid-lowering effects, and its precise mechanisms remain unclear. This study aims to investigate the lipid-reducing effects of CAP on oleic acid (OA)-induced lipid accumulation in HepG2 cells and explore the underlying mechanisms. The results showed that CAP exerted lipid-lowering effects by reducing triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and increasing high-density lipoprotein cholesterol (HDL-C) in OA-induced HepG2 cells. CAP modulated the relative expression levels of lipid metabolism-related genes, including ACC, PPAR-α, PPAR-γ, Fasn, CPT-1, SREBP-1C, and SCD-1 in HepG2 cells. Notably, CAP activated the PINK1/Parkin-mediated mitophagy pathway to alleviatie lipid accumulation. Treatment with the mitophagy inhibitor Mdivi-1 reversed the lipid-lowering effect of CAP, and silencing PINK1 gene using siRNA abolished lipid-lowering effect of CAP in HepG2 cells, confirming the critical involvement of the pathway. In conclusion, CAP targeted the PINK1 gene and activated the PINK1/Parkin signaling pathway to promote mitophagy, restoring cellular energy homeostasis and regulating lipid synthesis and degradation, ultimately reducing lipid accumulation. These findings provided a mechanistic basis for the potential use of CAP in developing novel natural therapies for lipid metabolic disorders and obesity management.