标题：The Hepatitis B Virus Polymerase Inhibits Rig-I- And Toll-Like Receptor 3-Mediated Interferon-{beta} Induction In Human Hepatocytes Through Interference With Interferon Regulatory Factor 3 Activation And Dampening Of The Interaction Between Tbk1/Ikk{varepsilon} And Ddx3.
作者：Yu S, Chen J, Wu M, Chen H, Yuan Z.
摘要：Hepatitis B virus (HBV) infection is still one of the most serious health problems worldwide. While studies have shown that HBV impairs interferon (IFN) production from dendritic cells (DCs) in chronic hepatitis B patients, it remains unknown whether HBV inhibits interferon production in human hepatocytes. Using transient transfection assays in primary human hepatocyte PH5CH8 cell line, we demonstrate that HBV polymerase inhibits IFN-beta promoter activity induced by Newcastle Disease Virus (NDV), Sendai Virus (SeV) or poly(I:C) in a dose-dependent manner, while ectopic expression of HBV Core and X proteins has no effect on IFN-beta promoter activity. In addition, HBV polymerase blocks cellular IFN-beta expression and consequent antiviral immunity revealed by an infection protection assay. Furthermore, over-expression of key molecules on the IFN-beta induction axis, together with HBV polymerase, resulted in a block of IFN-beta promoter activity triggered by RIG-I, IPS-1, TRIF, TBK1 and IKKepsilon, but not by an IFN regulatory factor 3 dominant-positive mutant (IRF3-5D); suggesting that HBV polymerase prevents IFN-beta expression at the TBK1/IKKepsilon level. Further studies show that HBV polymerase inhibits phosphorylation, dimerization and nuclear translocation of IRF3, in response to SeV infection. Finally, we demonstrate that HBV polymerase-mediated dampening of the interaction between TBK1/IKKepsilon and DDX3 can be involved in the inhibitory effect on IFN-beta induction. Taken together, our findings reveal a novel role of HBV polymerase in HBV counteraction of IFN-beta production in human hepatocytes.
Hepatitis B virus suppresses toll-like receptor-mediated innate immune responses in murine parenchymal and nonparenchymal liver cells.
Wu J, Meng Z, Jiang M, Pei R, Trippler M, Broering R, Bucchi A, Sowa JP, Dittmer U, Yang D, Roggendorf M, Gerken G, Lu M, Schlaak JF.
Department of Gastroenterology and Hepatology, University Hospital of Essen, Essen, Germany.
Abstract
We have previously shown that Toll-like receptor (TLR)-activated murine nonparenchymal liver cells [(NPC); Kupffer cells (KC), liver sinusoidal endothelial cells (LSEC)] can suppress hepatitis B virus (HBV) replication. Therefore, the aim of this study was to investigate whether HBV has the ability to counteract the TLR-mediated control of its replication. Freshly purified murine hepatocytes and NPCs obtained from C57BL6 mice were stimulated by TLR 1-9 ligands in the presence or absence of hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), HBV virions, or supernatants from HBV-producing HBV-Met cells, and HBV replication was suppressed by anti- hepatitis B virus X protein (HBx) small interfering RNA (siRNA) in HBV-Met cells. Supernatants were collected and tested for antiviral cytokines by viral protection assay. HBV gene expression and replication was analyzed by southern blot. RNA and proteins were analyzed by quantitative reverse transcription polymerase chain reaction (RT-PCR) or western blot and enzyme-linked immunosorbent assay, respectively. Pretreatment of hepatocytes and NPCs with HBV-Met cells supernatants, HBsAg, HBeAg, or HBV virions almost completely abrogated TLR-induced antiviral activity, which correlated with suppression of interferon beta (IFN-beta) production and subsequent interferon-stimulated gene induction as well as suppressed activation of interferon regulatory factor 3 (IRF-3), nuclear factor kappa B (NF-kappaB), and extracellular signal-regulated kinase (ERK) 1/2. In HBV-infected HBV-Met cells, TLR stimulation did not induce antiviral cytokines in contrast to primary hepatocytes. TLR-stimulated expression of proinflammatory cytokines [tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6)], and activation of IRF-3 was suppressed after up-regulation of HBV replication in HBV-Met cells. Accordingly, suppression of HBV replication by siRNA led to activation or expression of proinflammatory transcription factors and cytokines. CONCLUSION: Our data indicate that HBV can suppress the TLR-induced antiviral activity of liver cells. This has major implications for the interaction between HBV and the immune system.