Betulinic acid improves nonalcoholic fatty liver disease through YY1/FAS signaling pathway

The increasing prevalence of nonalcoholic fatty liver disease (NAFLD) worldwide indicates the urgent need to develop novel and effective treatment strategies. Betulinic acid (BA), a naturally occurring plant-derived pentacyclic triterpenoid, has an outstanding effect in improving metabolism. However, the pharmacological action and mechanism of BA in NAFLD remain unclear. Here, we show that BA-treated high-fat diet mice and methionine-choline deficient diet-fed mice are resistant to hepatic steatosis when compared with vehicle-treated mice. BA alleviates fatty acid synthesis, fibrosis, and inflammation and promotes fatty acid oxidation. Meanwhile, fatty acid synthase (FAS) expression and activity are markedly inhibited with BA treatment both in vitro and in vivo. Moreover, BA inhibits FAS expression through transcriptional suppression of Yin Yang 1 (YY1), leading to retard hepatocytes triglyceride accumulation. Collectively, BA protects hepatocytes from abnormal lipid deposition in NAFLD through YY1/FAS pathway. Our findings establish a novel role of BA in representing a possible therapeutic strategy to reverse NAFLD.