Hepatocyte‐specific Selenoi deficiency predisposes mice to hepatic steatosis and obesity

Abstract Selenoprotein I ( Selenoi ) is highly expressed in liver and plays a key role in lipid metabolism as a phosphatidylethanolamine (PE) synthase. However, the precise function of Selenoi in the liver remains elusive. In the study, we generated hepatocyte‐specific Selenoi conditional knockout (cKO) mice on a high‐fat diet to identify the physiological function of Selenoi . The cKO group exhibited a significant increase in body weight, with a 15.6% and 13.7% increase in fat accumulation in white adipose tissue (WAT) and the liver, respectively. Downregulation of the lipolysis‐related protein (p‐Hsl) and upregulation of the adipogenesis‐related protein (Fasn) were observed in the liver of cKO mice. The cKO group also showed decreased oxygen consumption (VO 2 ), carbon dioxide production (VCO 2 ), and energy expenditure ( p < .05). Moreover, various metabolites of the steroid hormone synthesis pathway were affected in the liver of cKO mice. A potential cascade of Selenoi ‐phosphatidylethanolamine‐steroid hormone synthesis might serve as a core mechanism that links hepatocyte‐specific Selenoi cKO to biochemical and molecular reactions. In conclusion, we revealed that Selenoi inhibits body fat accumulation and hepatic steatosis and elevates energy consumption; this protein could also be considered a therapeutic target for such related diseases.