Knockdown of regulator of Calcineurin 2 promotes transcription factor EB-mediated lipophagy to prevent non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease. The present work aimed to explore the function of regulator of Calcineurin 2 (RCAN2) in NAFLD and its related mechanisms. Mice were fed with high-fat diet (HFD) to construct NAFLD model. Adeno-associated virus injection was performed to interference with RCAN2 in mice. RCAN2 knockdown meliorated HFD-induced NAFLD and impaired glucose metabolism. Abnormal lipid metabolism and inflammation in HFD-fed mice were relieved when RCAN2 was downregulated. Besides, hepatocyte Huh-7 cells, treated with free fatty acids (oleic acid and palmitic acid), were used as NAFLD models in vitro. We found that knockdown of RCAN2 inhibited the accumulation of lipid droplets and inflammation induced by free fatty acids. RCAN2 interference increased the activity of calcineurin (CaN), which enhanced the nuclear translocation of Transcription factor EB (TFEB). Autophagosome and lysosome biogenesis was augmented, and autophagy-dependent lipid degradation (lipophagy) was promoted. Collectively, we demonstrate that RCAN2 insufficiency protects against NAFLD by promoting TFEB-mediated lipophagy.