Over IFI16 expression increased inflammation in Hepatitis B Virus-Associated Glomerulonephritis by Regulating Caspase-1 and IL-1 ß
Abstract Aims & background: IFI16 plays an important role in innate immunity against invasive microbial infection by sensing double-stranded DNA viruses due to caspase-1-dependent inflammasome activation and subsequent maturation and secretion of IL-1β. However, the role of IFI16 in regulating the immune response to viruses in vivo and in vitro, especially in sensing hepatitis B virus (HBV), has not been examined. We hypothesized that the expression of IFI16 increases corresponding to HBV-mediated inflammation in patients with hepatitis B virus associated glomerulonephritis (HBV-GN), a condition which activates inflammatory mechanisms and causes renal damage. To test this hypothesis, we therefore analyzed the expression of IFI16 and inflammatory factors in HBV-GN tissues and cell lines relative to the inflammatory response to HBV infection. Methods: A total 75 patients with chronic nephritis(CN) including 50 with HBV-GN and 25 with chronic glomerulonephritis (CCN) involved in this study. Each CN patient received renal biopsy, and immunohistochemistry(IHC) was used to detect the expression of IFI16 and inflammatory factors Caspase-1 and IL-1β in the biopsy specimens. Following IFI16 was transfected in HBV-infected and HBV-uninfected human glomerular mesangial (HGM) cell line and HEK-293T cell line, expression of Caspase-1 and IL-1β were detected by Western blot and qRT- PCR. Results: IFI16 expression in HBV-GN biopsies (80.0%) was significantly higher than in CGN (24.0%) and positively correlated with caspase-1 and IL-1𝛽 expression in HBV-GN. In vitro, over expression IFI16 increased caspase-1 and IL-1𝛽 expression in HBV -infected HGM and HEK-293T. Conclusions: The elevation of IFI16 during HBV infection or replication may contribute to renal damage due to inflammation, thus providing a putative therapeutic target and a new avenue for researching the pathogenesis of HBV-GN.