STING signaling activation inhibits HBV replication and attenuates the severity of liver injury and HBV-induced fibrosis.

The covalently closed circular DNA (cccDNA) of HBV plays a crucial role in viral persistence and is also a risk factor for developing HBV-induced diseases, including liver fibrosis. Stimulator of interferon genes (STING), a master regulator of DNA-mediated innate immune activation, is a potential therapeutic target for viral infection and virus-related diseases. In this study, agonist-induced STING signaling activation in macrophages was revealed to inhibit cccDNA-mediated transcription and HBV replication via epigenetic modification in hepatocytes. Notably, STING activation could efficiently attenuate the severity of liver injury and fibrosis in a chronic recombinant cccDNA (rcccDNA) mouse model, which is a proven suitable research platform for HBV-induced fibrosis. Mechanistically, STING-activated autophagic flux could suppress macrophage inflammasome activation, leading to the amelioration of liver injury and HBV-induced fibrosis. Overall, the activation of STING signaling could inhibit HBV replication through epigenetic suppression of cccDNA and alleviate HBV-induced liver fibrosis through the suppression of macrophage inflammasome activation by activating autophagic flux in a chronic HBV mouse model. This study suggests that targeting the STING signaling pathway may be an important therapeutic strategy to protect against persistent HBV replication and HBV-induced fibrosis.