Curcumin regulates endogenous and exogenous metabolism via Nrf2-FXR-LXR pathway in NAFLD mice

Background: Curcumin is a natural polyphenol with beneficial effects on NAFLD patients and NAFLD is accompanied by metabolism decompensation. Methods: This study was focused on the effect of curcumin on the relationship between endogenous bile acids metabolism pathway and exogenous xenobiotics metabolism pathway in C57BL/6 mice of non-alcoholic fatty liver disease induced by high-fat and high-fructose diet (HFHFr) and in cultured mice hepatocytes. Results: Our results showed curcumin treatment apparently attenuated the hepatic steatosis and reversed the abnormalities of serum biochemical parameters in HFHFr-fed mice. Curcumin effectively reversed the expression of CYP3A and CYP7A in fatty liver status to restore metabolism capability. In the meantime, lipid synthesis has been controlled by curcumin, evidenced by the expression of CD36, SREBP-lc and FAS. Further, FXR, SHP and Nrf2 expressions were remarkably dropped in HFHFr-fed mice and LXR alpha expression was significantly enhanced, while curcumin treatment was quite effective to restore this pathway. In addition, LXR alpha antagonist GGPP pretreatment weakened the curcumin effects on CYP3A, CYP7A and SREBP-1c. Conclusions: These findings indicate that the Nrf2/FXR/LXR alpha pathway might synergistically regulate both endogenous and exogenous metabolism in NAFLD mice and LXR alpha may be a novel therapeutic target of curcumin for the prevention and treatment of NAFLD.