Prevotella-Derived Butyrate Inhibits CD8T-Cell Glycolysis via AKT/mTOR Signalling to Alleviate MASH.

Abstract

BACKGROUND AND AIMS: Metabolic associated steatohepatitis (MASH) is a critical stage of MAFLD, lacking effective therapies. Gut microbiota and their metabolites, particularly short-chain fatty acids (SCFAs), are increasingly recognised as modulators of hepatic metabolism and immune responses. We investigated whether Prevotella could ameliorate MASH by regulating CD8T-cell metabolism. METHODS: Faecal samples from MASH patients and healthy controls were analysed by 16S rDNA sequencing and untargeted metabolomics. MASH mouse models, germ-free mice and ex vivo CD8T-cell cultures were used to assess the effects of Prevotella and butyrate on glycolysis, PI3K/AKT/mTOR signalling and liver pathology. Metabolic activity was measured using ECAR, 2-NBDG uptake and lactate production; molecular changes were evaluated by qPCR, western blotting and flow cytometry. RESULTS: 16S rDNA sequencing revealed a significant reduction of Prevotella abundance in MASH patients compared with healthy controls, which was inversely correlated with hepatic steatosis and CD8T-cell infiltration. In MCD diet-induced MASH mice, oral administration of Prevotella alleviated hepatic lipid accumulation and collagen deposition. In germ-free mice, colonisation with Prevotella similarly improved liver histology. Mechanistically, Prevotella suppressed glycolytic activity in CD8T cells, as shown by decreased 2-NBDG uptake, ECAR measurements and reduced expression of glycolytic enzymes (HK2, PKM2, LDHA). Additionally, Prevotella downregulated the PI3K/AKT/mTOR signalling pathway in CD8T cells, linking its metabolic effects to immune modulation. Notably, the combination of Prevotella with a glycolysis inhibitor did not further enhance its therapeutic efficacy compared with Prevotella alone, indicating that suppression of glycolysis is a major mechanism underlying Prevotella's protective effects. CONCLUSION: Prevotella mitigates MASH by downregulating the PI3K/AKT/mTOR-glycolysis axis in CD8T cells via butyrate-dependent mechanisms, highlighting its potential as a microbial therapeutic candidate for MASH.