Effect of high exposure of chlorogenic acid on lipid accumulation and oxidative stress in oleic acid-treated HepG2 cells

Abstract

ObjectiveTo evaluate the effect of high concentration of chlorogenic acid (CGA) on non-alcoholic fatty liver disease (NAFLD) in normal and oleic acid (OA) treated HepG2 cells, as well as the underlying mechanism involved in the fat accumulation, oxidative stress and insulin resistance (IR) induced by CGA treatment. MethodsOA (0.5 mmol/L) induced hepatic steatosis was established in HepG2 cells as an in vitro model of NAFLD. The normal and OA-treated HepG2 cells were treated by CGA (0, 0.5, 1, and 2 mmol/L) for 24 h, then cellular lipid droplets, reactive oxygen species (ROS), and glucose uptake were evaluated by Oil Red O staining and cellular biochemical assays, respectively. Signaling pathways involved in adipogenesis including SREBP-1c and PNPLA3, oxidative stress, and IR including CYP2E1 and CYP4A, were investigated by Western blot and RT-qPCR. ResultsCGA (0.5, 1, and 2 mmol/L) treatment increased the cellular lipid droplets and the expression of SREBP-1c and PNPLA3 in the tested cells. Additionally, 2-NBDG uptake was significantly increased, whereas the cellular ROS and protein levels of CYP2E1 and CYP4A were significantly decreased in OA-treated cells. ConclusionOur results suggest that high concentrations of CGA ameliorated OA-induced oxidative damage and IR likely by inhibiting the expression of CYP2E1 and CYP4A, and promoted lipid accumulation by inducing the expression of SREBP-1c and PNPLA3 in the tested cells.