Hexokinase-3 upregulation and histone H3K18 lactylation mediate murine liver fibrosis induced by Echinococcus multilocularis.

Alveolar echinococcosis (AE), caused by Echinococcus multilocularis infection, leads to destructive hepatic lesions and severe hepatic fibrosis. Lactylation, a post-translational modification, has been linked to fibrotic progression in hepatocytes. However, the role of E. multilocularis infection in hepatic lactylation remains unclear. This study aims to elucidate the relationship between hepatic fibrosis and lactylation induced by E. multilocularis infection and fill this knowledge gap. The results showed that lactate concentrations in the livers and sera of AE mice were significantly elevated compared with those in the control group. The relative mRNA expression of hexokinase isoforms in the liver tissue of AE mouse models revealed significant upregulation of hexokinase-3 (HK3), a key enzyme regulating lactate production. Immunofluorescence staining revealed substantial colocalization between HK3 and TGF-β1 in hepatic lesions of AE mice. Western blot analysis using a pan-lactylation antibody showed significantly elevated lactylation levels in the livers of AE mice compared with controls, with a significant increase in histone H3 lysine 18 lactylation (H3K18la). CUT&Tag analysis revealed differential enrichment of H3K18la at multiple fibrosis-associated genes in AE mouse liver. In vitro, AML-12 hepatocytes exposed to E. multilocularis culture supernatant showed significant upregulation of TGF-β1, HK3, and histone lactylation. HK3 knockdown significantly reduced the induction of H3K18la and fibrosis-related proteins, whereas exogenous lactate supplementation significantly increased these responses despite HK3 silencing, confirming that lactate acts downstream of HK3 to drive histone lactylation and fibrogenesis. Corosolic acid, a compound that limits HK3-mediated lactate production, attenuated histone lactylation and fibrosis-related protein expression. These findings indicate that HK3-driven histone lactylation at H3K18 contributes to hepatic fibrosis in AE, and suggest that HK3 may serve as promising therapeutic targets for AE.