ATOH8 promotes HBV immune tolerance by inhibiting the pyroptotic pathway in hepatocytes.

Abstract

The mechanism of hepatitis B virus (HBV) immune tolerance remains unclear. Our previous studies showed that ATOH8 plays an important role in the liver tumor immune microenvironment; however, the specific immune regulatory mechanism requires further studies. Studies have shown that the hepatitis C virus (HCV) can cause hepatocyte pyroptosis; however, the relationship between HBV and pyroptosis is contested. Therefore, this study aimed to determine whether ATOH8 interfered with HBV activity through pyroptosis to further study the mechanism of ATOH8 on immune regulation and enrich our understanding of HBV‑induced invasion. The expression levels of pyroptosis‑related molecules (GSDMD and Caspase‑1) in liver cancer tissues and peripheral blood mononuclear cells (PBMCs) of patients with HBV were assessed using qPCR and western blotting. HepG2.2.15 and Huh7 cells were used to overexpress ATOH8 using a recombinant lentiviral vector. The HBV DNA expression levels in HepG2.2.15 cells were detected using absolute quantitative (q)PCR, and the hepatitis B surface antigen expression levels in the HepG2.2.15 cell culture supernatant were measured using ELISA. The expression of pyroptosis‑related molecules in Huh7 and HepG2.2.15 cells was detected using western blotting and qPCR. Additionally, the expression levels of inflammatory factors including TNF‑α, INF‑α, IL‑18, and IL‑1β were detected using qPCR and ELISA. The liver cancer tissues and PBMCs of patients with HBV showed higher expressions of pyroptosis‑related molecules than those of normal samples. ATOH8‑overexpressed HepG2.2.15 cells had higher HBV expression levels but lower levels of pyroptosis‑related molecules, such as GSDMD and Caspase‑1, than those in the control group. Similarly, the expression levels of pyroptosis‑related molecules in Huh7 cells overexpressing ATOH8 were lower than that in Huh7‑GFP cells. Further detection of the expression of INF‑α and TNF‑α in HepG2.2.15 cells overexpressing ATOH8 showed that ATOH8 overexpression increased the expression of these inflammatory factors, including those associated with pyroptosis (IL‑18 and IL‑1β). In conclusion, ATOH8 promoted HBV immune escape by inhibiting hepatocyte pyroptosis.