GP73 facilitates hepatitis B virus replication by repressing the NF-κB signaling pathway

Hepatitis B virus (HBV) chronically infects approximately 350 million people worldwide, and 600 000 deaths are caused by HBV-related hepatic failure. Golgi protein 73 (GP73) is a serum biomarker for liver diseases, including chronic hepatitis B. Here, we determine the effect of HBV infection on GP73 production and characterized the role of GP73 in HBV replication. Initially, we show that GP73 is highly produced in the sera of HBV-positive patients with chronic liver diseases and in HBV-stimulated leukocytes. In addition, HBV stimulation promotes GP73 production in peripheral blood mononuclear cells isolated from healthy donors and in macrophages derived from human acute monocytic leukemia cells (THP-1). Notably, the hepatitis B surface antigen (HBsAg), but not HBV replication, is required for the activation of GP73 expression. Moreover, in HepG2 cells and Huh7 cells, GP73 facilitates HBV replication and represses nuclear factor kappa B p50 expression, which in turn represses HBV replication and GP73 expression. Finally, we demonstrate that GP73 facilitates HBV replication by repressing the innate immune response and the nuclear factor kappa B signaling pathway. Taken together, we revealed a distinct positive feedback mechanism between HBV replication and GP73 production and suggest that GP73 acts as a potential antiviral target for HBV infection.