Exosomes From Hepatitis B Virus-Infected Hepatocytes Induce Liver Fibrosis Through METTL3-Mediated m6A Modification...

Exosomes derived from hepatitis B virus (HBV)-infected hepatocytes (HBV-Exo) promote liver fibrosis. Emerging evidence implicates METTL3 and P2RX7 as critical drivers of liver fibrosis. However, the molecular mechanisms by which HBV-Exo drive hepatic fibrosis remain poorly understood. This study investigated the mechanistic involvement of METTL3 and P2RX7 in this fibrotic process. Exosomes from pHBV1.3-transfected, HBV-replicating THLE-2 hepatocytes (HBV-THLE-2-Exo) were isolated and used to incubate LX-2 hepatic stellate cells (HSCs). Impacts on LX-2 cells were evaluated by detecting cell viability, proliferation, invasion, migration, and fibrosis marker expression. MeRIP, RIP, RNA pull-down, and mRNA stability assays were used to assess the METTL3/P2RX7 mRNA interaction. A CCl₄-induced mouse model of liver fibrosis was generated to elucidate the role in vivo. HBV-THLE-2-Exo elevated METTL3 levels in recipient LX-2 HSCs. HBV-THLE-2-Exo enhanced the proliferation, invasion, migration, and fibrosis marker expression in LX-2 HSCs in vitro. Moreover, METTL3-depleted exosomes (si-METTL3-HBV-THLE-2-Exo) attenuated LX-2 cell proliferation, invasion, migration, and expression of fibrotic markers compared to HBV-THLE-2-Exo. Mechanistically, METTL3 stabilized P2RX7 in an IGF2BP1-m6A-dependent manner. P2RX7 overexpression reversed si-METTL3-HBV-THLE-2-Exo-mediated alterations in LX-2 cell proliferation, invasion, migration, and fibrosis marker expression in vitro. Additionally, HBV-THLE-2-Exo exacerbated liver fibrosis in CCl₄-induced mice. Our findings unveil a novel METTL3/P2RX7 axis by which HBV-Exo drive HSC activation and liver fibrosis. These findings elucidate a novel exosome-mediated regulatory axis in liver fibrosis, suggesting the therapeutic potential of targeting METTL3/P2RX7 axis.