Chronic hepatitis B virus infection imbalances short-chain fatty acids and amino acids in the liver and gut via microbiota modulation.

The commensal microbiota is closely related to HBV infection and HBV-related liver diseases; however, how HBV and viral components dynamically affect the targeted organ liver microbiota is not well-known. In this study, an HBV-carrier mouse model established by HBsAg⁺ hepatocyte replacement in Fah^-/- recipient mice, named HBs-HepR mice, was used to analyze the microbiota and metabolomics at the time of triggering the specific anti-HBV CD8⁺ T cell response in the liver. The composition and relative abundance of microbiota were both altered in the gut and liver of HBs-HepR mice. Particularly, increased Muribaculaceae and Alloprevotella, and decreased Lachnospiraceae-NK4A136 and Rikenella were observed in the gut; while increased Ralstonia and Geobacillus were observed in the liver of HBs-HepR mice. Furthermore, changes in microbial functions were revealed. There were no significant differences in the levels of SCFAs in fecal and serum; however, decreased propionic acid and acetic acid were detected in the livers of HBs-HepR mice, which was negatively related to the abundance of Geobacillus in the liver. Significantly decreased levels of 9 kinds of amino acids were detected in the feces of HBs-HepR mice, which was positively related to decreased Rikenella in the gut. A significant increase in L-glycine was observed in the liver and serum, positively related to the abundance of Geobaillus in the livers of HBs-HepR mice. In conclusion, chronic HBV infection imbalanced SCFA and amino acid metabolism by modulating microbiota in the liver, unlike in the gut, which was involved in the immune activation phase.