BMSC-derived extracellular vesicles affect gluconeogenesis and lipogenesis by releasing 5'-tRF-GlyCCC to improve MAFLD insulin sensitivity

TsRNAs (tRNA-derived small RNAs) also known as tRNA-derived small RNAs, are a relatively new type of non-coding RNAs that have demonstrated promising effect in treating various liver diseases. However, the function of small extracellular vesicles (sEVs) secreted by human bone marrow mesenchymal stem cells (BMSCs) in safeguarding against metabolic-associated fatty liver disease (MAFLD) is still uncertain. In this research, we explored the effects of BMSCs sEVs on lipid metabolism using Palmitic Acid (PA)-induced HepG2 cells, both in the presence and absence of the sEVs inhibitor GW4869. Pandora sequencing and RNA sequencing were utilized to identify differentially expressed genes in sEVs and hepatocytes in vitro. Furthermore, we carried out in vivo studies involving male C57BL/6J mice that fed with high-fat diet (HFD) and either treated with an AAV 5'-tRF-GlyCCC mimic or not, through tail vein injection. Our findings revealed that BMSC-sEVs can relieve lipid accumulation in PA-caused HepG2 cells by inhibiting the formation of de novo fatty acid. We found that 5'-tRF-GlyCCC forms a direct connection with the 3' UTR of FoxO3, thereby decreasing the level of gluconeogenic genes PEPCK and G6Pase. Tail vein administration of the 5'-tRF-GlyCCC AAV alleviated liver gluconeogenesis and lipid metabolism issues in MAFLD mice by enhancing hepatic insulin sensitivity. The results imply that the 5'-tRF-GlyCCC/FoxO3 gluconeogenesis-signaling pathway could be crucial in the therapeutic benefits of BMSC sEVs on MAFLD.