scholarly journals JMJD6 negatively regulates cytosolic RNA induced antiviral signaling by recruiting RNF5 to promote activated IRF3 K48 ubiquitination

2021 ◽  
Vol 17 (3) ◽  
pp. e1009366
Author(s):  
Wei Zhang ◽  
Qi Wang ◽  
Fan Yang ◽  
Zixiang Zhu ◽  
Yueyue Duan ◽  
...  
Keyword(s):  
Immune Responses ◽  
Type I Interferon ◽  
Sendai Virus ◽  
Rna Virus ◽  
Negative Regulator ◽  
Viral Rna ◽  
Poly I:C ◽  
Type I ◽  
Dependent Manner ◽  
Antiviral Signaling

The negative regulation of antiviral immune responses is essential for the host to maintain homeostasis. Jumonji domain-containing protein 6 (JMJD6) was previously identified with a number of functions during RNA virus infection. Upon viral RNA recognition, retinoic acid-inducible gene-I-like receptors (RLRs) physically interact with the mitochondrial antiviral signaling protein (MAVS) and activate TANK-binding kinase 1 (TBK1) to induce type-I interferon (IFN-I) production. Here, JMJD6 was demonstrated to reduce type-I interferon (IFN-I) production in response to cytosolic poly (I:C) and RNA virus infections, including Sendai virus (SeV) and Vesicular stomatitis virus (VSV). Genetic inactivation of JMJD6 enhanced IFN-I production and impaired viral replication. Our unbiased proteomic screen demonstrated JMJD6 contributes to IRF3 K48 ubiquitination degradation in an RNF5-dependent manner. Mice with gene deletion of JMJD6 through piggyBac transposon-mediated gene transfer showed increased VSV-triggered IFN-I production and reduced susceptibility to the virus. These findings classify JMJD6 as a negative regulator of the host’s innate immune responses to cytosolic viral RNA.

scholarly journals SARS-CoV-2 nsp12 attenuates type I interferon production by inhibiting IRF3 nuclear translocation

2021 ◽  
Author(s):  
Wenjing Wang ◽  
Zhuo Zhou ◽  
Xia Xiao ◽  
Zhongqin Tian ◽  
Xiaojing Dong ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Type I Interferon ◽  
Sendai Virus ◽  
Polymerase Activity ◽  
Poly I:C ◽  
Type I ◽  
Dependent Manner ◽  
Promoter Activation ◽  
Global Pandemic ◽  
Antiviral Innate Immunity

AbstractSARS-CoV-2 is the pathogenic agent of COVID-19, which has evolved into a global pandemic. Compared with some other respiratory RNA viruses, SARS-CoV-2 is a poor inducer of type I interferon (IFN). Here, we report that SARS-CoV-2 nsp12, the viral RNA-dependent RNA polymerase (RdRp), suppresses host antiviral responses. SARS-CoV-2 nsp12 attenuated Sendai virus (SeV)- or poly(I:C)-induced IFN-β promoter activation in a dose-dependent manner. It also inhibited IFN promoter activation triggered by RIG-I, MDA5, MAVS, and IRF3 overexpression. Nsp12 did not impair IRF3 phosphorylation but suppressed the nuclear translocation of IRF3. Mutational analyses suggested that this suppression was not dependent on the polymerase activity of nsp12. Given these findings, our study reveals that SARS-CoV-2 RdRp can antagonize host antiviral innate immunity and thus provides insights into viral pathogenesis.

scholarly journals Feline Infectious Peritonitis Virus Nsp5 Inhibits Type I Interferon Production by Cleaving NEMO at Multiple Sites

Viruses ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 43 ◽  
Author(s):  
Si Chen ◽  
Jin Tian ◽  
Zhijie Li ◽  
Hongtao Kang ◽  
Jikai Zhang ◽  
...  
Keyword(s):  
Type I Interferon ◽  
Sendai Virus ◽  
Nuclear Factor Κb ◽  
Poly I:C ◽  
Type I ◽  
Dependent Manner ◽  
Type I Ifn ◽  
Feline Infectious Peritonitis Virus ◽  
Feline Infectious Peritonitis ◽  
Polycytidylic Acid

Feline infectious peritonitis (FIP), caused by virulent feline coronavirus, is the leading infectious cause of death in cats. The type I interferon (type I IFN)-mediated immune responses provide host protection from infectious diseases. Several coronaviruses have been reported to evolve diverse strategies to evade host IFN response. However, whether feline infectious peritonitis virus (FIPV) antagonizes the type I IFN signaling remains unclear. In this study, we demonstrated that FIPV strain DF2 infection not only failed to induce interferon-β (IFN-β) and interferon-stimulated gene (ISG) production, but also inhibited Sendai virus (SEV) or polyinosinic-polycytidylic acid (poly(I:C))-induced IFN-β production. Subsequently, we found that one of the non-structural proteins encoded by the FIPV genome, nsp5, interrupted type I IFN signaling in a protease-dependent manner by cleaving the nuclear factor κB (NF-κB) essential modulator (NEMO) at three sites—glutamine132 (Q132), Q205, and Q231. Further investigation revealed that the cleavage products of NEMO lost the ability to activate the IFN-β promoter. Mechanistically, the nsp5-mediated NEMO cleavage disrupted the recruitment of the TRAF family member-associated NF-κB activator (TANK) to NEMO, which reduced the phosphorylation of interferon regulatory factor 3 (IRF3), leading to the inhibition of type I IFN production. Our research provides new insights into the mechanism for FIPV to counteract host innate immune response.

scholarly journals ARF-like Protein 16 (ARL16) Inhibits RIG-I by Binding with Its C-terminal Domain in a GTP-dependent Manner

2011 ◽  
Vol 286 (12) ◽  
pp. 10568-10580 ◽  
Author(s):  
Yong-Kang Yang ◽  
Hong Qu ◽  
Dong Gao ◽  
Wei Di ◽  
Hai-Wei Chen ◽  
...  
Keyword(s):  
Family Member ◽  
Sendai Virus ◽  
Rna Virus ◽  
Cell Types ◽  
Type I ◽  
Dependent Manner ◽  
Homologous Proteins ◽  
Downstream Signaling ◽  
Terminal Domain ◽  
Inhibitory Function

Retinoic acid-inducible gene I (RIG-I) recognizes RNA virus-derived nucleic acids, which leads to the production of type I interferon (IFN) in most cell types. Tight regulation of RIG-I activity is important to prevent ultra-immune responses. In this study, we identified an ARF-like (ARL) family member, ARL16, as a protein that interacts with RIG-I. Overexpression of ARL16, but not its homologous proteins ARL1 and ARF1, inhibited RIG-I-mediated downstream signaling and antiviral activity. Knockdown of endogenous ARL16 by RNAi potentiated Sendai virus-induced IFN-β expression and vesicular stomatitis virus replication. ARL16 interacted with the C-terminal domain (CTD) of RIG-I to suppress the association between RIG-I and RNA. ARL16 (T37N) and ARL16Δ45–54, which were restricted to the GTP-disassociated form, did not interact with RIG-I and also lost the inhibitory function. Furthermore, we suggest that endogenous ARL16 changes to GTP binding status upon viral infection and binds with the RIG-I CTD to negatively control its signaling activity. These findings suggested a novel innate immune function for an ARL family member, and a GTP-dependent model in which RIG-I is regulated.

scholarly journals NSUN2-mediated m5C methylation of IRF3 mRNA negatively regulates type I interferon responses

2021 ◽  
Author(s):  
Hongyun Wang ◽  
Lu Zhang ◽  
Cong Zeng ◽  
Jiangpeng Feng ◽  
Yu Zhou ◽  
...  
Keyword(s):  
Viral Infection ◽  
Type I Interferon ◽  
Sendai Virus ◽  
Negative Regulator ◽  
Interferon Response ◽  
Rna Modification ◽  
Type I ◽  
Mrna Levels ◽  
Interferon Responses

5-Methylcytosine (m5C) is a widespread post-transcriptional RNA modification and is reported to be involved in manifold cellular responses and biological processes through regulating RNA metabolism. However, its regulatory role in antiviral innate immunity has not yet been elucidated. Here, we report that NSUN2, a typical m5C methyltransferase, can negatively regulate type I interferon responses during viral infection. NSUN2 specifically mediates m5C methylation of IRF3 mRNA and accelerates its degradation, resulting in low levels of IRF3 and downstream IFN-β production. Knockout or knockdown of NSUN2 could enhance type I interferon responses and downstream ISG expression after viral infection in vitro. And in vivo, the antiviral innate responses is more dramatically enhanced in Nsun2+/− mice than in Nsun2+/+ mice. Four highly m5C methylated cytosines in IRF3 mRNA were identified, and their mutation could enhance the cellular IRF3 mRNA levels. Moreover, infection with Sendai virus (SeV), vesicular stomatitis virus (VSV), herpes simplex virus 1 (HSV-1), Zika virus (ZIKV), or especially SARS-CoV-2 resulted in a reduction in endogenous levels of NSUN2. Together, our findings reveal that NSUN2 serves as a negative regulator of interferon response by accelerating the fast turnover of IRF3 mRNA, while endogenous NSUN2 levels decrease after viral infection to boost antiviral responses for the effective elimination of viruses. Our results suggest a paradigm of innate antiviral immune responses ingeniously involving NSUN2-mediated m5C modification.

scholarly journals PP2A Facilitates Porcine Reproductive and Respiratory Syndrome Virus Replication by Deactivating irf3 and Limiting Type I Interferon Production

Viruses ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 948 ◽  
Author(s):  
Jiayu Xu ◽  
Lu Zhang ◽  
Yunfei Xu ◽  
He Zhang ◽  
Junxin Gao ◽  
...  
Keyword(s):  
Virus Infection ◽  
Therapeutic Target ◽  
Type I Interferon ◽  
Negative Regulator ◽  
Host Cells ◽  
Respiratory Syndrome Virus ◽  
Target Cells ◽  
Type I ◽  
Dependent Manner ◽  
Pp2a Activity

Protein phosphatase 2A (PP2A), a major serine/threonine phosphatase in mammalian cells, is known to regulate the kinase-driven intracellular signaling pathways. Emerging evidences have shown that the PP2A phosphatase functions as a bona-fide therapeutic target for anticancer therapy, but it is unclear whether PP2A affects a porcine reproductive and respiratory syndrome virus infection. In the present study, we demonstrated for the first time that inhibition of PP2A activity by either inhibitor or small interfering RNA duplexes in target cells significantly reduced their susceptibility to porcine reproductive and respiratory syndrome virus (PRRSV) infection. Further analysis revealed that inhibition of PP2A function resulted in augmented production of type I interferon (IFN). The mechanism is that inhibition of PP2A activity enhances the levels of phosphorylated interferon regulatory factor 3, which activates the transcription of IFN-stimulated genes. Moreover, inhibition of PP2A activity mainly blocked PRRSV replication in the early stage of viral life cycle, after virus entry but before virus release. Using type I IFN receptor 2 specific siRNA in combination with PP2A inhibitor, we confirmed that the effect of PP2A on viral replication within target cells was an interferon-dependent manner. Taken together, these findings demonstrate that PP2A serves as a negative regulator of host cells antiviral responses and provides a novel therapeutic target for virus infection.

scholarly journals The Interferon-Induced Exonuclease ISG20 Exerts Antiviral Activity through Upregulation of Type I Interferon Response Proteins

mSphere ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Christopher M. Weiss ◽  
Derek W. Trobaugh ◽  
Chengqun Sun ◽  
Tiffany M. Lucas ◽  
Michael S. Diamond ◽  
...  
Keyword(s):  
Virus Replication ◽  
Type I Interferon ◽  
Rna Virus ◽  
Ectopic Expression ◽  
Viral Rna ◽  
Interferon Response ◽  
Type I ◽  
Venezuelan Equine Encephalitis ◽  
Wild Type ◽  
In Cells

ABSTRACTType I interferon (IFN)-stimulated genes (ISGs) have critical roles in inhibiting virus replication and dissemination. Despite advances in understanding the molecular basis of ISG restriction, the antiviral mechanisms of many remain unclear. The 20-kDa ISG ISG20 is a nuclear 3′–5′ exonuclease with preference for single-stranded RNA (ssRNA) and has been implicated in the IFN-mediated restriction of several RNA viruses. Although the exonuclease activity of ISG20 has been shown to degrade viral RNAin vitro, evidence has yet to be presented that virus inhibition in cells requires this activity. Here, we utilized a combination of an inducible, ectopic expression system and newly generatedIsg20−/−mice to investigate mechanisms and consequences of ISG20-mediated restriction. Ectopically expressed ISG20 localized primarily to Cajal bodies in the nucleus and restricted replication of chikungunya and Venezuelan equine encephalitis viruses. Although restriction by ISG20 was associated with inhibition of translation of infecting genomic RNA, degradation of viral RNAs was not observed. Instead, translation inhibition of viral RNA was associated with ISG20-induced upregulation of over 100 other genes, many of which encode known antiviral effectors. ISG20 modulated the production of IFIT1, an ISG that suppresses translation of alphavirus RNAs. Consistent with this observation, the pathogenicity of IFIT1-sensitive alphaviruses was increased inIsg20−/−mice compared to that of wild-type viruses but not in cells ectopically expressing ISG20. Our findings establish an indirect role for ISG20 in the early restriction of RNA virus replication by regulating expression of other ISGs that inhibit translation and possibly other activities in the replication cycle.IMPORTANCEThe host immune responses to infection lead to the production of type I interferon (IFN), and the upregulation of interferon-stimulated genes (ISGs) reduces virus replication and virus dissemination within a host. Ectopic expression of the interferon-induced 20-kDa exonuclease ISG20 suppressed replication of chikungunya virus and Venezuelan equine encephalitis virus, two mosquito-vectored RNA alphaviruses. Since the replication of alphavirus genomes occurs exclusively in the cytoplasm, the mechanism of nucleus-localized ISG20 inhibition of replication is unclear. In this study, we determined that ISG20 acts as a master regulator of over 100 genes, many of which are ISGs. Specifically, ISG20 upregulated IFIT1 genes and inhibited translation of the alphavirus genome. Furthermore, IFIT1-sensitive alphavirus replication was increased inIsg20−/−mice compared to the replication of wild-type viruses but not in cells ectopically expressing ISG20. We propose that ISG20 acts as an indirect regulator of RNA virus replication in the cytoplasm through the upregulation of many other ISGs.

scholarly journals Combating viral contaminants in CHO cells by engineering STAT1 mediated innate immunity

2018 ◽  
Author(s):  
Austin W.T. Chiang ◽  
Shangzhong Li ◽  
Benjamin P. Kellman ◽  
Gouri Chattopadhyay ◽  
Yaqin Zhang ◽  
...  
Keyword(s):  
Cho Cells ◽  
Rna Virus ◽  
Mammalian Cell Culture ◽  
Encephalomyocarditis Virus ◽  
Poly I:C ◽  
Type I ◽  
Dependent Manner ◽  
Viral Contaminants ◽  
Vesicular Stomatitis ◽  
Biopharmaceutical Manufacturing

AbstractViral contamination in biopharmaceutical manufacturing can lead to shortages in the supply of critical therapeutics. To facilitate the protection of bioprocesses, we explored the basis for the susceptibility of CHO cells, the most commonly used cell line in biomanufacturing, to RNA virus infection. Upon infection with certain ssRNA and dsRNA viruses, CHO cells fail to generate a significant interferon (IFN) response. Nonetheless, the downstream machinery for generating IFN responses and its antiviral activity is intact in these cells: treatment of cells with exogenously-added type I IFN or poly I:C prior to infection limited the cytopathic effect from Vesicular stomatitis virus (VSV), Encephalomyocarditis virus (EMCV), and Reovirus-3 virus (Reo-3) in a STAT1-dependent manner. To harness the intrinsic antiviral mechanism, we used RNA-Seq to identify two upstream repressors of STAT1: Gfi1 and Trim24. By knocking out these genes, the engineered CHO cells exhibited increased resistance to the prototype RNA viruses tested. Thus, omics-guided engineering of mammalian cell culture can be deployed to increase safety in biotherapeutic protein production among many other biomedical applications.

The Tissue Factor/Thrombin/Protease-Activated Receptor 1 Pathway Enhances Double-Strand RNA Induced Immune Responses in Macrophages

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4114-4114
Author(s):  
Silvio Antoniak ◽  
Kohei Tatsumi ◽  
Nigel Mackman
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Tissue Factor ◽  
Rna Virus ◽  
Innate Immune ◽  
Poly I:C ◽  
Type I ◽  
Innate Immune Responses ◽  
Protease Activated Receptor 1 ◽  
Viral Responses

Abstract Introduction: Co-regulation of the immune response and the coagulation cascade after infection is thought to be an ancient response to limit pathogen spread. Recently, we showed that activation of the thrombin receptor, protease-activated receptor 1 (PAR1), on fibroblasts enhanced the innate immune responses to RNA virus infection. Here, we investigated whether PAR1 activation by the extrinsic coagulation pathway contributes to dsRNA-induced innate immune responses in macrophages. Methods: Activation of the type-I interferon (IFN) pathway in the murine macrophage cell line RAW264.7 and bone-marrow derived macrophages (BMDM) from WT and PAR1-/- was analyzed after dsRNA (poly I:C) and/or PAR-1 stimulation. In addition, innate immune responses in the spleen were analyzed in vivo 4 hours after poly I:C (8mg/kg) injection in mice with reduced tissue factor expression (LowTF) or global PAR1 deletion (PAR1-/-) as well as in WT mice with a thrombin inhibitor (dabigatran etexilate, 10g/kg chow) or PAR-1 inhibitor (SCH79797, 25μg/kg). Lastly, we investigated the innate immune response in the spleen of WT and PAR1-/-mice after infection with the single-stranded RNA virus coxsackievirus B3. Results: RAW264.7 and BMDM exhibited a toll-like receptor 3 dependent induction of IFNβ and CXCL10 after poly I:C stimulation. Activation of PAR-1 with either thrombin or agonist peptide enhanced poly I:C induction of IFNβ and CXCL10. A deficiency of tissue factor levels, thrombin inhibition, PAR-1 inhibition or PAR1 deficiency resulted in reduced expression levels of type-I IFNs and IFN-response genes such as CXCL10 in the spleen and plasma in mice given poly I:C. Last, PAR1-/-mice exhibited impaired IFNβ immune response 4 days after coxsackievirus B3 infection compared to WT mice. Conclusion: Our study indicates that the coagulation dependent activation of PAR1 on macrophages is important for anti-viral responses to dsRNA. We speculate that PAR1 inhibition may interfere with anti-viral responses in humans. Disclosures No relevant conflicts of interest to declare.

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