TMAO regulates OTUB1-mediated SLC7A11 stability to promote NAFLD progression.

Trimethylamine N-oxide (TMAO) is a metabolite of the intestinal microbiota and is closely associated with the occurrence and development of Non-alcoholic fatty liver disease (NAFLD). Ferroptosis is a novel form of cell death and an important pathological mechanism exacerbating NAFLD. However, whether TMAO can promote ferroptosis and worsen NAFLD, as well as its related mechanisms, has not been studied. We used palmitic acid (PA) to induce HepG2 cell models and a high-fat diet to construct NAFLD animal models in mice. Western blotting, co-immunoprecipitation (CO-IP), and immunofluorescence were used to validate molecular pathways. ELISA was used to assess TMAO, oxidative markers, and biochemical parameters in serum and cell supernatant; HE staining and oil red O staining were used for histopathological examination. Higher levels of TMAO, MDA, and lower levels of SOD and GSH were found in the serum of NAFLD patients. TMAO promotes ferroptosis to accelerate the progression of NAFLD both in vivo and in vitro. At the cellular level, TMAO inhibits OTUB1, possibly weakening its interaction with SLC7A11, thereby promoting ferroptosis. TMAO induces ferroptosis, which accelerates the progression of NAFLD via the OTUB1/SLC7A11 axis. This provides new insights on the role of intestinal microbiota metabolites in the mechanisms of NAFLD.