Autophagy mediates perfluorooctanoic acid-induced lipid metabolism disorder and NLRP3 inflammasome activation in hepatocytes

Abstract

Perfluorooctanoic acid (PFOA) has applications in numerous industrial products and is an industrial waste that is persistently present in the environment. Exposure to PFOA results in nonalcoholic fatty liver disease (NAFLD). However, the underlying mechanisms remain unclear. In this study, male C57BL/6 mice were exposed to PFOA (1 mg/kg/day) for 4 weeks to evaluate the effect of PFOA, and the human liver cell line (L-02) was used to observe the direct effect of PFOA in vitro. After PFOA exposure, the expression of genes related to hepatic lipogenesis, the NLRP3 inflammasome, and autophagy were measured. We found that exposure to PFOA induced lipid accumulation and stimulated lipogenesis in both mouse livers and L-02 cells. In addition, increased NLRP3 aggregation and enhanced production of IL-1β occurred after PFOA treatment. We also found that PFOA exposure induced autophagosome formation and p62 accumulation, indicating blockage of autophagic flux. Rapamycin alleviated PFOA-induced lipid accumulation and NLRP3 inflammasome activation by activating autophagic flux. Conversely, chloroquine, an autophagic flux inhibitor, exacerbated PFOA-induced lipid accumulation and NLRP3 inflammasome activation. Collectively, these results provide evidence to show that PFOA-induced blockade of autophagic flux causes an increase in lipid synthesis and inflammation in vivo and in vitro.