Intestinal TM6SF2 protects against metabolic dysfunction-associated steatohepatitis through the gut–liver axis

Transmembrane-6 superfamily member 2 (TM6SF2) regulates hepatic fat metabolism and is associated with metabolic dysfunction-associated steatohepatitis (MASH). TM6SF2 genetic variants are associated with steatotic liver disease. The pathogenesis of MASH involves genetic factors and gut microbiota alteration, yet the role of host-microbe interactions in MASH development remains unclear. Here, we discover that mice with intestinal epithelial cell-specific knockout of Tm6sf2 (Tm6sf2^ΔIEC) develop MASH, accompanied by impaired intestinal barrier and microbial dysbiosis. Transplanting stools from Tm6sf2^ΔIEC mice induces steatohepatitis in germ-free recipient mice, whereas MASH is alleviated in Tm6sf2^ΔIEC mice co-housed with wild-type mice. Mechanistically, Tm6sf2-deficient intestinal cells secrete more free fatty acids by interacting with fatty acid-binding protein 5 to induce intestinal barrier dysfunction, enrichment of pathobionts, and elevation of lysophosphatidic acid (LPA) levels. LPA is translocated from the gut to the liver, contributing to lipid accumulation and inflammation. Pharmacological inhibition of the LPA receptor suppresses MASH in both Tm6sf2^ΔIEC and wild-type mice. Hence, modulating microbiota or blocking the LPA receptor is a potential therapeutic strategy in TM6SF2 deficiency-induced MASH.