International Session(Workshop)1(JSGE・JSH・JSGCS)
Thu. November 2nd   14:30 - 17:00   Room 11: Portopia Hotel South Wing Topaz
Identification of Novel Antiviral Host Factors using in vitro HBV Infection Assay Systems
Takuto Nosaka1, Masahiro Ohtani1, Yasunari Nakamoto1
1Second Department of Internal Medicine, University of Fukui
Aim: Curing HBV infection requires elimination of cccDNA. We established a human hepatocyte HBV infection system and reported that IFN-g regulates cccDNA via STAT1-related pathway (Hepatol Res. 2020, 2022). In this study, using in vitro HBV infection systems, novel antiviral host factors that regulate cccDNA and their molecular mechanisms were investigated by functional gene expression analysis.
Methods: The 1.3-mer HBV genome plasmid with core promoter A1762T/G1764A and precore G1896A mutation was transfected into HepG2 cells and "HepG2.D11 clone" was established. The supernatant containing HBV was added to primary human hepatocytes (PXB cells). siRNA knockdown and RNA microarray were performed.
Results: In STAT1 knockdown experiment, HBsAg, intracellular HBV DNA, and cccDNA were decreased in PXB cells, whereas HBV DNA was increased in HepG2.D11 cells (PXB/HepG2.D11: 0.51/1.91 folds). In 66 genes changed with PXB si-STAT1 in RNA microarray, siRNA screening showed that knockdown of two anti-HBV candidate genes, fumarylacetoacetate hydrolase (FAH) and Nicotinamide N- methyltransferase (NNMT), elevated HBsAg and cccDNA. In these genes, FAH catalyzes fumaric acid in hepatocytes. Addition of dimethyl fumarate to HepG2.D11 cells decreased HBsAg and HBV DNA (p<0.05).
Conclusion: We identified novel antiviral host factors, FAH and NNMT, that reduce HBV cccDNA levels using in vitro HBV infection systems. A couple of host factors were found to contribute to the control of viral infection independently of STAT1 by comprehensive functional screening.
Index Term 1: HBV
Index Term 2: FAH
Page Top