Byakangelicin alleviates metabolic dysfunction-associated steatohepatitis by selective inhibition of non-canonical MTORC1 signaling pathway

blocked the alleviation effects of Bya on hepatic steatosis, inflammation, insulin resistance, and fibrosis in mice, while reintroduction of TFEB restored these effects. We identified Bya directly bound to MET370 and PHE552 of FLCN (folliculin), suppressing the function of the FLCN-FNIP1 (folliculin interacting protein 1)/FNIP2 complex, which in turn inhibited MTORC1-mediated cytoplasmic sequestration of TFEB. Mutation of FLCN (M370A and F552A) in the liver abolished Bya-induced protection against MASH. Thus, Bya is a promising therapeutic natural compound for MASH, and selective inhibition of MTORC1 is a potential approach to treat this disease.