Discovery of Betulinic Acid Derivatives as Potent Intestinal Farnesoid X Receptor Antagonists to Ameliorate Nonalcoholic Steatohepatitis.

Farnesoid X receptor (FXR) has emerged as a promising therapeutic target for nonalcoholic steatohepatitis (NASH) because of its tightly interwoven relationship with bile acid homeostasis, inflammation, fibrosis, and glucose and lipid metabolism. Evidence showed that intestinal FXR antagonism exhibited remarkable metabolic improvements in mice. Herein, we developed a series of betulinic acid derivatives as potent intestinal FXR antagonists, and F6 was identified as the most potent one with an IC50 at 2.1 μM. F6 selectively inhibited intestinal FXR signaling and ameliorated the hepatic steatosis, inflammation, and fibrosis in Gubra-amylin NASH (GAN) and high-fat with methionine and choline deficiency (HFMCD) diet-induced NASH models. The beneficial effects were achieved by direct antagonism of intestinal FXR and feedback activation of hepatic FXR, thereby decreasing ceramides and repressing inflammasome activation in the liver. Collectively, our work substantially supports F6 as a promising drug candidate against NASH and demonstrates that antagonism of intestinal FXR signaling is a practical strategy for treating metabolic diseases.