Activation Of Intracellular Innate Immunity Inhibits HBV And HIV Infection

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TLR3 Activation of Hepatic Stellate Cells Suppresses HBV ReplicationHepatitis B virus(HBV)is a hepatotropic DNA virus and its infection results in hepatitis B,liver cirrhosis and hepatocellular carcinoma,representing a major health problem worldwide.Interferon(IFN)and nucleos(t)ide analogues(NAs)are the predominant treatments for HBV infection.Because the current therapy fail to eliminate the viral covalently closed circular DNA(cccDNA),HBV could not be cured.Although most adults produce the protective antibodies after vaccination,approximately 5-10%of people have no response to the vaccine.So the development of therapy to cure HBV and more effective vaccine remain the important parts to eradicate HBV infection.The aim of this study is to investigate that whether hapetic stellae cells(HSC)involve in the innate immunity against HBV infection.HSC is a type of hepatic pericyte,locating between hepatocytes and liver sinusoidal endothelial cell.HSC participates in the process of liver fibrosis.Liver injury causes the activation of HSC,and activated HSC promote the migration and deposition of extracellular matrix,which leads to liver fibrosis.Recent studies have demonstrated that HSC has the role in the liver innate immunity.However,there is little information about the role of HSC in the liver innate immunity against HBV infectionAs an important pattern recognition receptor for virus recognition,Toll-like receptor 3(TLR3)could sense intracellular double-strained RNA(dsRNA)and initiate intracellular innate immune response.In this study,we used dsRNA mimic(PolyI:C)to activate the TLR3 signaling pathway in HSC and predominated the induction of IFNs and antiviral factors.The result showed PolyI:C could activate TLR3 signaling pathway in HSC,and facilitate the phosphorylation of interferon regulatory factor 3(IRF3)and IRF7,resulting in the selective upregulation of IFN-?and IFN-?.The induction of IFNs was independent of RIG-I signaling.The supernatant(SN)from TLR3-activated HSC significantly inhibited HBV replication in hepatocytes(HepG2).The pretreatment of neutralization antibodies to IFN-p and IFN-? receptors could largely block the HSC SN action,which demonstrated that IFN-? and IFN-? appeared to contribute to HSC SN-mediated HBV inhibition.Mechanistically,LX-2 SN treatment of the HepG2 cells activated JAK/STAT signaling pathway and induced a number of anti viral Interferon stimulated genes(ISG).These ISGs(ISG20,ISG54,ISG56,OAS-1,Trim22 and Trim25)could inhibit HBV replication at different steps of viral life cycle.Our findings above demonstrated that the activation of TLR3/IFN signaling pathway in non-target cell of HBV(bystander cell)resulted in the induction of multiple anti-HBV factors,leading to HBV inhibition in hepatovytes.This research work provides important experimental evidence for development of immune activation-based therapy for HBV infection.Future investigations with animal or human liver tissues are necessary in order to prove that HSC indeed participate in liver innate immunity against HBV infection.Part ? Activation of cytosolic DNA sensors inhibit HIV infection of macrophagesInnate immunity provides the first defense line to protect host from viral infections.DNA and activation of DNA sensors are the essential components of innate immunity system and activate the antiviral immunity response by sensing the viral DNA.Currently,several DNA sensors have been identified to recognize a number of DNA virus.The DNA sensors were activated by cytosolic DNA and induce interferon(IFN)expression,which has the antiviral effect.It was documented that the RNA:DNA intermediate,ssDNA and dsDNA produced during HIV life cycle could be sensed by DNA sensors.Macrophages are the major immune cells in the innate immune system and play an important role against HIV infection.Macrophages are the target cells of HIV.However,HIV has evolved multiple mechanisms to evade the antiviral immunity in macrophages and causes the persistent and latent infection.Therefore,the activation of innate immunity is crucial to suppress HIV infection in macrophages.The aim of this study is to investigate the effect of DNA sensors activation on HIV infection/replication of macrophages and the mechanisms.Poly(dA:dT)and poly(dG:dC),which are the ligands of DNA sensors,were used to activate the DNA sensors in macrophages and initiate innate immune response.In this study,we found that DNA sensors activation in macrophage could significantly suppress HIV infection of macrophages.Mechanmsmly,the activation of DNA sensors by the ligand facilitated the phosphorylation of IFN regulatory factor 3(IRF3)and IRF7,and upregulated the expression of type I and III IFN.The secreted IFNs combine with their receptors on the cell surface and activate the JAK/STAT signaling pathway that enhanced the expression of IFN stimulate genes(ISGs:ISG15,ISG56,Viperin,OAS2,GBP5,MxB and Tetherin)and HIV restriction microRNAs(miRNA-29c,miRNA-138,miRNA-146a,miRNA-155,miRNA-198 and miRNA-223).These antiviral factors have been shown to have the ability to interfere with HIV life cycle at different steps.These anti-HIV factors are relative with IFN expression,because the neutralization antibodies to IFN receptors compromised the antiviral effect mediated by DNA sensors activation.In addition,we demonstrated that DNA sensor activation induced the expression of CC chemokines in macrophages and significantly inhibited HIV Strong Stop DNA,which is the first reverse transcription product after HIV entry.These results suggested that CC chemokimes mediated by DNA sensors activation could inhibit HIV entry of macrophages by combining with HIV coreceptor competitively.