Silibinin Targeting Heat Shock Protein 90 Represents a Novel Approach to Alleviate Nonalcoholic Fatty Liver Disease by Simultaneously Lowering Hepatic Lipotoxicity and Enhancing Gut Barrier Function

Abstract

Nonalcoholic fatty liver disease (NAFLD) is a clinicopathological condition characterized by intrahepatic ectopic steatosis. Due to the increase in high-calorie diets and sedentary lifestyles, NAFLD has surpassed viral hepatitis and become the most prevalent chronic liver disease globally. Silibinin, a natural compound, has shown promising therapeutic potential for the treatment of liver diseases. Nevertheless, the ameliorative effects of silibinin on NAFLD have not been completely understood, and the underlying mechanism is elusive. Therefore, in this study, we used high-fat diet (HFD)-induced mice and free fatty acid (FFA)-stimulated HepG2 cells to investigate the efficacy of silibinin for the treatment of NAFLD and elucidate the underlying mechanisms. In vivo, silibinin showed significant efficacy in inhibiting adiposity, improving lipid profile levels, ameliorating hepatic histological aberrations, healing the intestinal epithelium, and restoring gut microbiota compositions. Furthermore, in vitro, silibinin effectively inhibited FFA-induced lipid accumulation in HepG2 cells. Mechanistically, we reveal that silibinin possesses the ability to ameliorate hepatic lipotoxicity by suppressing the heat shock protein 90 (Hsp90)/peroxisome proliferator-activated receptor-γ (PPARγ) pathway and alleviating gut dysfunction by inhibiting the Hsp90/NOD-like receptor pyrin domain-containing 3 (NLRP3) pathway. Altogether, our findings provide evidence that silibinin is a promising candidate for alleviating the "multiple-hit" in the progression of NAFLD.