Hepatic Clstn3 Ameliorates Lipid Metabolism Disorders in High Fat Diet-Induced NAFLD through Activation of FXR.

Non-alcoholic fatty liver disease (NAFLD) has become serious liver disease all over the world. At present, NAFLD caused by high calorie and fat diet is increasing. Calsyntenin-3 (Clstn3) is a transmembrane protein that has recently been found to participate in lipid energy metabolism. But whether Clstn3 affects NAFLD lipid metabolism has not been analyzed. We stimulate the mice primary hepatocytes (MPHs) with oleic acid and palmitic acid (OA&PA) to establish a cell model. Then, potential targets, including Clstn3 gene, were validated for improving lipid metabolism disorder in NAFLD model mice (HFD and db/db) by silencing and overexpressing hepatic Clstn3. Moreover, the effects of Clstn3 on lipid homeostasis were determined by functional determination, triglyceride (TG) levels, total cholesterol (TC) levels, ELISA, and qRT-PCR detection. Our results displayed that Clstn3 was decreased in the NAFLD mice model. Also, overexpression of Clstn3 improved lipid metabolism disorders, gluconeogenesis, and energy homeostasis and reduced liver injury, inflammation, and oxidative stress injury. However, opposite results were obtained in Clstn3-silencing mice, suggesting that the Clstn3 gene is closely related to lipid metabolism disorder in NAFLD. RNAseq expression demonstrated that Farnesoid X Receptor (FXR) expression was increased after overexpression of Clstn3. Clstn3 supplementation in FXRKO mice can improve the dysfunction caused by insufficient FXR, suggesting that Clstn3 can improve the NAFLD lipid metabolism disorder to some extent through FXR, which may provide a new method for the treatment of NAFLD.