Helicobacter hepaticus promotes liver fibrosis through oxidative stress induced by hydrogenase in BALB/c mice

Background: It has been documented that Helicobacter hepaticus produces a nickel-containing hydrogen-oxidizing hydrogenase enzyme, which is necessary for hydrogen-supported amino acid uptake. Although H. hepaticus infection has been shown to promote liver inflammation and fibrosis in BALB/c mice, the impact of hydrogenase on the progression of liver fibrosis induced by H. hepaticus has not been explored.Materials and Methods: BALB/c mice were inoculated with hydrogenase mutant (?HyaB) or wild type (WT) H. hepaticus 3B1 for 12 and 24 weeks. H. hepaticus colonization, hepatic histopathology, serum biochemistry, expression of inflammatory cytokines, and oxidative stress signaling pathways were detected.Results: We found that ?HyaB had no influence on the colonization of H. hepaticus in the liver of mice at 12 and 24 weeks post infection (WPI). However, mice infected by ?HyaB strains developed significantly alleviated liver inflammation and fibro-sis compared with WT infection. Moreover, ?HyaB infection remarkably increased the expression of hepatic GSH, SOD, and GSH- Px, and decreased the liver levels of MDA, ALT, and AST compared to WT H. hepaticus infected group from 12 to 24 WPI. Furthermore, mRNA levels of Il-6, Tnf-a, iNos, Hmox-1, and a-SMA were significantly decreased with an increase of Nfe2l2 in the liver of mice infected by ?HyaB strains. In addition, ?HyaB H. hepaticus restored the activation of the Nrf2/HO- 1 signaling pathway, which is inhibited by H. hepaticus infection.Conclusions: These data demonstrated that H. hepaticus hydrogenase promoted liver inflammation and fibrosis development mediated by oxidative stress in male BALB/c mice.

Automated summary

This study found that Helicobacter hepaticus produces a nickel-containing hydrogenase enzyme that promotes liver inflammation and fibrosis. However, the impact of a mutated form of this enzyme on liver fibrosis has not been explored.