Mst1 inhibition attenuates non-alcoholic fatty liver disease via reversing Parkin-related mitophagy

Obesity-related non-alcoholic fatty liver disease (NAFLD) is connected with mitochondrial stress and hepatocyte apoptosis. Parkin-related mitophagy sustains mitochondrial homeostasis and hepatocyte viability. However, the contribution and regulatory mechanisms of Parkin-related mitophagy in NAFLD are incompletely understood. Macrophage stimulating 1 (Mst1) is a novel mitophagy upstream regulator which excerbates heart and cancer apoptosisn via repressing mitophagy activity. The aim of our study is to explore whether Mst1 contributes to NAFLD via disrupting Parkin-related mitophagy. A NAFLD model was generated in wild-type (WT) mice and Mst1 knockout (Mst1-KO) mice using high-fat diet (HFD). Cell experiments were conducted via palmitic acid (PA) treatment in the primary hepatocytes. The results in our study demonstrated that Mst1 was significantly upregulated in HFD-treated livers. Genetic ablation of Mst1 attenuated HFD-mediated hepatic injury and sustained hepatocyte viability. Functional studies illustrated that Mst1 knockdown reversed Parkin-related mitophagy and the latter protected mitochondria and hepatocytes against HFD challenge. Besides, we further figured out that Mst1 modulated Parkin expression via the AMPK pathway; blockade of AMPK repressed Parkin-related mitophagy and recalled hepatocytes mitochondrial apoptosis. Altogether, our data identified that NAFLD was closely associated with the defective Parkin-related mitophagy due to Mst1 upregulation. This finding may pave the road to new therapeutic modalities for the treatment of fatty liver disease.