scholarly journals SARS-CoV-2 Spike Antagonizes Innate Antiviral Immunity by Targeting Interferon Regulatory Factor 3

2022 ◽  
Vol 11 ◽  
Author(s):  
Raul S. Freitas ◽  
Tyler F. Crum ◽  
Kislay Parvatiyar
Keyword(s):  
Immune Response ◽  
Transcription Factor ◽  
Virus Disease ◽  
Ectopic Expression ◽  
Interferon Regulatory Factor ◽  
Type I ◽  
Regulatory Factor ◽  
Interferon Regulatory Factor 3 ◽  
Antiviral Immune Response ◽  
Corona Virus

Corona virus disease 2019 (COVID-19) pathogenesis is intimately linked to the severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) and disease severity has been associated with compromised induction of type I interferon (IFN-I) cytokines which coordinate the innate immune response to virus infections. Here we identified the SARS-CoV-2 encoded protein, Spike, as an inhibitor of IFN-I that antagonizes viral RNA pattern recognition receptor RIG-I signaling. Ectopic expression of SARS-CoV-2 Spike blocked RIG-I mediated activation of IFNβ and downstream induction of interferon stimulated genes. Consequently, SARS-CoV-2 Spike expressing cells harbored increased RNA viral burden compared to control cells. Co-immunoprecipitation experiments revealed SARS-CoV-2 Spike associated with interferon regulatory factor 3 (IRF3), a key transcription factor that governs IFN-I activation. Co-expression analysis via immunoassays further indicated Spike specifically suppressed IRF3 expression as NF-κB and STAT1 transcription factor levels remained intact. Further biochemical experiments uncovered SARS-CoV-2 Spike potentiated proteasomal degradation of IRF3, implicating a novel mechanism by which SARS-CoV-2 evades the host innate antiviral immune response to facilitate COVID-19 pathogenesis.

scholarly journals Vpu Mediates Depletion of Interferon Regulatory Factor 3 during HIV Infection by a Lysosome-Dependent Mechanism

2012 ◽  
Vol 86 (16) ◽  
pp. 8367-8374 ◽  
Author(s):  
Brian P. Doehle ◽  
Kristina Chang ◽  
Arjun Rustagi ◽  
John McNevin ◽  
M. Juliana McElrath ◽  
...  
Keyword(s):  
Immune Response ◽  
Hiv Infection ◽  
Interferon Regulatory Factor ◽  
Innate Immune ◽  
Productive Infection ◽  
Type I ◽  
Regulatory Factor ◽  
Interferon Regulatory Factor 3 ◽  
Antiviral Immune Response ◽  
Immune Defenses

HIV has evolved sophisticated mechanisms to avoid restriction by intracellular innate immune defenses that otherwise serve to control acute viral infection and virus dissemination. Innate defenses are triggered when pattern recognition receptor (PRR) proteins of the host cell engage pathogen-associated molecule patterns (PAMPs) present in viral products. Interferon regulatory factor 3 (IRF3) plays a central role in PRR signaling of innate immunity to drive the expression of type I interferon (IFN) and interferon-stimulated genes (ISGs), including a variety of HIV restriction factors, that serve to limit viral replication directly and/or program adaptive immunity. Productive infection of T cells by HIV is dependent upon the targeted proteolysis of IRF3 that occurs through a virus-directed mechanism that results in suppression of innate immune defenses. However, the mechanisms by which HIV controls innate immune signaling and IRF3 function are not defined. Here, we examined the innate immune response induced by HIV strains identified through their differential control of PRR signaling. We identified viruses that, unlike typical circulating HIV strains, lack the ability to degrade IRF3. Our studies show that IRF3 regulation maps specifically to the HIV accessory protein Vpu. We define a molecular interaction between Vpu and IRF3 that redirects IRF3 to the endolysosome for proteolytic degradation, thus allowing HIV to avoid the innate antiviral immune response. Our studies reveal that Vpu is an important IRF3 regulator that supports acute HIV infection through innate immune suppression. These observations define the Vpu-IRF3 interface as a novel target for therapeutic strategies aimed at enhancing the immune response to HIV.

scholarly journals Positive Regulation of Interferon Regulatory Factor 3 Activation by Herc5 via ISG15 Modification

2010 ◽  
Vol 30 (10) ◽  
pp. 2424-2436 ◽  
Author(s):  
He-Xin Shi ◽  
Kai Yang ◽  
Xing Liu ◽  
Xin-Yi Liu ◽  
Bo Wei ◽  
...  
Keyword(s):  
Sendai Virus ◽  
Specific Binding ◽  
Ectopic Expression ◽  
Interferon Regulatory Factor ◽  
Type I Interferons ◽  
Type I ◽  
Regulatory Factor ◽  
Interferon Regulatory Factor 3 ◽  
Antiviral Responses ◽  
Irf3 Activation

ABSTRACT Virus infection induces host antiviral responses, including induction of type I interferons. Transcription factor interferon regulatory factor 3 (IRF3) plays a pivotal role and is tightly regulated in this process. Here, we identify HERC5 (HECT domain and RLD 5) as a specific binding protein of IRF3 by immunoprecipitation. Ectopic expression or knockdown of HERC5 could, respectively, enhance or impair IRF3-mediated gene expression. Mechanistically, HERC5 catalyzes the conjugation of ubiquitin-like protein ISG15 onto IRF3 (Lys193, -360, and -366), thus attenuating the interaction between Pin1 and IRF3, resulting in sustained IRF3 activation. In contrast to results for wild-type IRF3, the mutant IRF3(K193,360,366R) interacts tightly with Pin1, is highly polyubiquitinated, and becomes less stable upon Sendai virus (SeV) infection. Consistently, host antiviral responses are obviously boosted or crippled in the presence or absence of HERC5, respectively. Collectively, this study characterizes HERC5 as a positive regulator of innate antiviral responses. It sustains IRF3 activation via a novel posttranslational modification, ISGylation.

scholarly journals Regulated Nuclear-Cytoplasmic Localization of Interferon Regulatory Factor 3, a Subunit of Double-Stranded RNA-Activated Factor 1

2000 ◽  
Vol 20 (11) ◽  
pp. 4159-4168 ◽  
Author(s):  
K. Prasanna Kumar ◽  
Kevin M. McBride ◽  
Brian K. Weaver ◽  
Colin Dingwall ◽  
Nancy C. Reich
Keyword(s):  
Transcription Factor ◽  
Nuclear Localization ◽  
Nuclear Export ◽  
Interferon Regulatory Factor ◽  
Nuclear Accumulation ◽  
Type I ◽  
Cytoplasmic Localization ◽  
Regulatory Factor ◽  
Interferon Regulatory Factor 3 ◽  
Double Stranded Rna

ABSTRACT Viral double-stranded RNA (dsRNA) generated during the course of infection leads to the activation of a latent transcription factor, dsRNA-activated factor 1 (DRAF1). DRAF1 binds to a DNA target containing the type I interferon-stimulated response element and induces transcription of responsive genes. DRAF1 is a multimeric transcription factor containing the interferon regulatory factor 3 (IRF-3) protein and one of the histone acetyl transferases, CREB binding protein (CBP) or p300 (CBP/p300). In uninfected cells, the IRF-3 component of DRAF1 resides in the cytoplasm. The cytoplasmic localization of IRF-3 is dependent on a nuclear export signal, and we demonstrate IRF-3 recognition by the chromosome region maintenance 1 (CRM1) (also known as exportin 1) shuttling receptor. Following infection and specific phosphorylation, IRF-3 accumulates in the nucleus where it associates with CBP and p300. We identify a nuclear localization signal (NLS) in IRF-3 that is critical for nuclear accumulation. Mutation of the NLS abrogates nuclear localization even following infection. The NLS appears to be active constitutively, but it is recognized by only a subset of importin-α shuttling receptors. Evidence is presented to support a model in which IRF-3 normally shuttles between the nucleus and the cytoplasm but cytoplasmic localization is dominant prior to infection. Following infection, phosphorylated IRF-3 can bind to the CBP/p300 proteins resident in the nucleus. We provide the evidence of a role for CBP/p300 binding in the nuclear sequestration of a transcription factor that normally resides in the cytoplasm.

scholarly journals DHAV-1 Blocks the Signaling Pathway Upstream of Type I Interferon by Inhibiting the Interferon Regulatory Factor 7 Protein

2021 ◽  
Vol 12 ◽  
Author(s):  
Yalan Lai ◽  
Xiaoyan Xia ◽  
Anchun Cheng ◽  
Mingshu Wang ◽  
Xumin Ou ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immunity ◽  
Viral Protein ◽  
Interferon Regulatory Factor ◽  
Host Cells ◽  
Luciferase Reporter ◽  
Type I ◽  
Dependent Manner ◽  
Regulatory Factor ◽  
Interferon Regulatory Factor 7

Duck hepatitis A virus (DHAV), which mainly infects 1- to 4-week-old ducklings, has a fatality rate of 95% and poses a huge economic threat to the duck industry. However, the mechanism by which DHAV-1 regulates the immune response of host cells is rarely reported. This study examined whether DHAV-1 contains a viral protein that can regulate the innate immunity of host cells and its specific regulatory mechanism, further exploring the mechanism by which DHAV-1 resists the host immune response. In the study, the dual-luciferase reporter gene system was used to screen the viral protein that regulates the host innate immunity and the target of this viral protein. The results indicate that the DHAV-1 3C protein inhibits the pathway upstream of interferon (IFN)-β by targeting the interferon regulatory factor 7 (IRF7) protein. In addition, we found that the 3C protein inhibits the nuclear translocation of the IRF7 protein. Further experiments showed that the 3C protein interacts with the IRF7 protein through its N-terminus and that the 3C protein degrades the IRF7 protein in a caspase 3-dependent manner, thereby inhibiting the IFN-β-mediated antiviral response to promote the replication of DHAV-1. The results of this study are expected to serve as a reference for elucidating the mechanisms of DHAV-1 infection and pathogenicity.

scholarly journals Regulation of Type I Interferon Gene Expression by Interferon Regulatory Factor-3

1998 ◽  
Vol 273 (5) ◽  
pp. 2714-2720 ◽  
Author(s):  
Susan L. Schafer ◽  
Rongtuan Lin ◽  
Paul A. Moore ◽  
John Hiscott ◽  
Paula M. Pitha
Keyword(s):  
Gene Expression ◽  
Type I Interferon ◽  
Interferon Regulatory Factor ◽  
Type I ◽  
Regulatory Factor ◽  
Interferon Regulatory Factor 3 ◽  
Interferon Gene

scholarly journals The 3C Protein of Enterovirus 71 Inhibits Retinoid Acid-Inducible Gene I-Mediated Interferon Regulatory Factor 3 Activation and Type I Interferon Responses

2010 ◽  
Vol 84 (16) ◽  
pp. 8051-8061 ◽  
Author(s):  
Xiaobo Lei ◽  
Xinlei Liu ◽  
Yijie Ma ◽  
Zhenmin Sun ◽  
Yaowu Yang ◽  
...  
Keyword(s):  
Rna Binding ◽  
Type I Interferon ◽  
Critical Role ◽  
Enterovirus 71 ◽  
Interferon Regulatory Factor ◽  
Type I ◽  
Regulatory Factor ◽  
Interferon Regulatory Factor 3 ◽  
Retinoid Acid ◽  
Inducible Gene

ABSTRACT Enterovirus 71 (EV71) is a human pathogen that induces hand, foot, and mouth disease and fatal neurological diseases. Immature or impaired immunity is thought to associate with increased morbidity and mortality. In a murine model, EV71 does not facilitate the production of type I interferon (IFN) that plays a critical role in the first-line defense against viral infection. Administration of a neutralizing antibody to IFN-α/β exacerbates the virus-induced disease. However, the molecular events governing this process remain elusive. Here, we report that EV71 suppresses the induction of antiviral immunity by targeting the cytosolic receptor retinoid acid-inducible gene I (RIG-I). In infected cells, EV71 inhibits the expression of IFN-β, IFN-stimulated gene 54 (ISG54), ISG56, and tumor necrosis factor alpha. Among structural and nonstructural proteins encoded by EV71, the 3C protein is capable of inhibiting IFN-β activation by virus and RIG-I. Nevertheless, EV71 3C exhibits no inhibitory activity on MDA5. Remarkably, when expressed in mammalian cells, EV71 3C associates with RIG-I via the caspase recruitment domain. This precludes the recruitment of an adaptor IPS-1 by RIG-I and subsequent nuclear translocation of interferon regulatory factor 3. An R84Q or V154S substitution in the RNA binding motifs has no effect. An H40D substitution is detrimental, but the protease activity associated with 3C is dispensable. Together, these results suggest that inhibition of RIG-I-mediated type I IFN responses by the 3C protein may contribute to the pathogenesis of EV71 infection.

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