scholarly journals Rubicon Modulates Antiviral Type I Interferon (IFN) Signaling by Targeting IFN Regulatory Factor 3 Dimerization

2017 ◽  
Vol 91 (14) ◽  
Author(s):  
Jae-Hoon Kim ◽  
Tae-Hwan Kim ◽  
Hyun-Cheol Lee ◽  
Chamilani Nikapitiya ◽  
Md Bashir Uddin ◽  
...  
Keyword(s):  
Type I Interferon ◽  
Cellular Mechanism ◽  
Negative Regulator ◽  
Type I ◽  
Type I Ifn ◽  
Regulatory Factor ◽  
Antiviral Responses ◽  
Proinflammatory Responses ◽  
Feedback Inhibitor

ABSTRACT Rubicon is part of a Beclin-1-Vps34-containing autophagy complex. Rubicon induces antimicrobial responses upon Toll-like receptor (TLR) stimulation and functions as a feedback inhibitor to prevent unbalanced proinflammatory responses depending on dectin-1 signaling. However, the role played by Rubicon during antiviral immune responses, particularly the type I interferon (IFN) responses, remains largely unknown. Here, we report that Rubicon acts as a negative regulator for virus-triggered IFN signaling. Knockdown of Rubicon promoted type I interferon signaling and inhibited virus replication, while overexpression of Rubicon had the opposite effect. Rubicon specifically interacts with the interferon regulatory factor (IRF) association domain (IAD) of IRF3, and this interaction leads to inhibition of the dimerization of IRF3, which negatively regulates IFN-mediated antiviral response. Thus, our findings suggest the novel additional role of Rubicon as a negative regulator that inhibits the IFN signaling and cellular antiviral responses, providing a novel cellular mechanism of IRF3 inhibition. IMPORTANCE The type I IFN system is a critical innate immune response that protects organisms against virus infection. However, type I IFN signaling must be tightly regulated to avoid excessive production of IFNs. Hence, negative regulatory mechanisms for type I IFN signaling are important, and to date, several related molecules have been identified. Here, we show that Rubicon is a major negative regulator of type I IFN signaling, and unlike previous reports of cellular molecules that inhibit IRF3 activation via proteasomal degradation or dephosphorylation of IRF3, we show that Rubicon interacts with IRF3 and that ultimately this interaction leads to inhibition of the dimerization of IRF3. Thus, we identified a novel negative regulator of type I IFN signaling pathways and a novel cellular mechanism of IRF3 inhibition. The results of this study will increase our understanding of the role of negative-feedback mechanisms that regulate type I IFN signaling and maintain immune homeostasis.

scholarly journals Peste des Petits Ruminants Virus Nucleocapsid Protein Inhibits Beta Interferon Production by Interacting with IRF3 To Block Its Activation

2019 ◽  
Vol 93 (16) ◽  
Author(s):  
Zixiang Zhu ◽  
Pengfei Li ◽  
Fan Yang ◽  
Weijun Cao ◽  
Xiangle Zhang ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Type I Interferon ◽  
Interferon Regulatory Factor ◽  
Type I ◽  
Peste Des Petits Ruminants ◽  
Type I Ifn ◽  
Regulatory Factor ◽  
N Protein ◽  
Beta Interferon ◽  
Natural Hosts

ABSTRACTPeste des petits ruminants virus (PPRV) is the etiological agent of peste des petits ruminants, causing acute immunosuppression in its natural hosts. However, the molecular mechanisms by which PPRV antagonizes the host immune responses have not been fully characterized. In particular, how PPRV suppresses the activation of the host RIG-I-like receptor (RLR) pathway has yet to be clarified. In this study, we demonstrated that PPRV infection significantly suppresses RLR pathway activation and type I interferon (IFN) production and identified PPRV N protein as an extremely important antagonistic viral factor that suppresses beta interferon (IFN-β) and IFN-stimulated gene (ISG) expression. A detailed analysis showed that PPRV N protein inhibited type I IFN production by targeting interferon regulatory factor 3 (IRF3), a key molecule in the RLR pathway required for type I IFN induction. PPRV N protein interacted with IRF3 (but not with other components of the RLR pathway, including MDA5, RIG-I, VISA, TBK1, and MITA) and abrogated the phosphorylation of IRF3. As expected, PPRV N protein also considerably impaired the nuclear translocation of IRF3. The TBK1-IRF3 interaction was involved significantly in IRF3 phosphorylation, and we showed that PPRV N protein inhibits the association between TBK1 and IRF3, which in turn inhibits IRF3 phosphorylation. The amino acid region 106 to 210 of PPRV N protein was determined to be essential for suppressing the nuclear translocation of IRF3 and IFN-β production, and the 140 to 400 region of IRF3 was identified as the crucial region for the N-IRF3 interaction. Together, our findings demonstrate a new mechanism evolved by PPRV to inhibit type I IFN production and provide structural insights into the immunosuppression caused by PPRV.IMPORTANCEPeste des petits ruminants is a highly contagious animal disease affecting small ruminants, which threatens both small livestock and endangered susceptible wildlife populations in many countries. The causative agent, peste des petits ruminants virus (PPRV), often causes acute immunosuppression in its natural hosts during infection. Here, for the first time, we demonstrate that N protein, the most abundant protein of PPRV, plays an extremely important role in suppression of interferon regulatory factor 3 (IRF3) function and type I interferon (IFN) production by interfering with the formation of the TBK1-IRF3 complex. This study explored a novel antagonistic mechanism of PPRV.

130 STAT3 is a negative regulator of type I IFN-induced antiviral responses

Cytokine ◽  
2008 ◽  
Vol 43 (3) ◽  
pp. 266-267 ◽  
Author(s):  
Wei-Bei Wang ◽  
Chien-Kuo Lee
Keyword(s):  
Negative Regulator ◽  
Type I ◽  
Type I Ifn ◽  
Antiviral Responses

scholarly journals Interferon regulatory factor 7 (IRF7) represents a link between inflammation and fibrosis in the pathogenesis of systemic sclerosis

2019 ◽  
Vol 78 (11) ◽  
pp. 1583-1591 ◽  
Author(s):  
Minghua Wu ◽  
Brian Skaug ◽  
Xiongjie Bi ◽  
Tingting Mills ◽  
Gloria Salazar ◽  
...  
Keyword(s):  
Systemic Sclerosis ◽  
Interferon Regulatory Factor ◽  
Dermal Fibroblasts ◽  
Type I ◽  
Type I Ifn ◽  
Hydroxyproline Content ◽  
Regulatory Factor ◽  
Dermal Fibrosis ◽  
Interferon Regulatory Factor 7

ObjectivesThere is considerable evidence that implicates dysregulation of type I interferon signalling (or type I IFN signature) in the pathogenesis of systemic sclerosis (SSc). Interferon regulatory factor 7 (IRF7) has been recognised as a master regulator of type I IFN signalling. The objective of this study was to elucidate the role of IRF7 in dermal fibrosis and SSc pathogenesis.MethodsSSc and healthy control skin biopsies were investigated to determine IRF7 expression and activation. The role of IRF7 in fibrosis was investigated using IRF7 knockout (KO) mice in the bleomycin-induced and TSK/+mouse models. In vitro experiments with dermal fibroblasts from patients with SSc and healthy controls were performed.ResultsIRF7 expression was significantly upregulated and activated in SSc skin tissue and explanted SSc dermal fibroblasts compared with unaffected, matched controls. Moreover, IRF7 expression was stimulated by IFN-α in dermal fibroblasts. Importantly, IRF7 co-immunoprecipitated with Smad3, a key mediator of transforming growth factor (TGF)-β signalling, and IRF7 knockdown reduced profibrotic factors in SSc fibroblasts. IRF7 KO mice demonstrated attenuated dermal fibrosis and inflammation compared with wild-type mice in response to bleomycin. Specifically, hydroxyproline content, dermal thickness as well as Col1a2, ACTA2 and interleukin-6 mRNA levels were significantly attenuated in IRF7 KO mice skin tissue. Furthermore, IRF7 KO in TSK/+mice attenuated hydroxyproline content, subcutaneous hypodermal thickness, Col1a2 mRNA as well as α-smooth muscle actin and fibronectin expression.ConclusionsIRF7 is upregulated in SSc skin, interacts with Smad3 and potentiates TGF-β-mediated fibrosis, and therefore may represent a promising therapeutic target in SSc.

scholarly journals The Lyme Disease Spirochete Borrelia burgdorferi Utilizes Multiple Ligands, Including RNA, for Interferon Regulatory Factor 3-Dependent Induction of Type I Interferon-Responsive Genes

2010 ◽  
Vol 78 (7) ◽  
pp. 3144-3153 ◽  
Author(s):  
Jennifer C. Miller ◽  
Heather Maylor-Hagen ◽  
Ying Ma ◽  
John H. Weis ◽  
Janis J. Weis
Keyword(s):  
Borrelia Burgdorferi ◽  
Gene Transcription ◽  
Type I Interferon ◽  
Interferon Regulatory Factor ◽  
Lyme Arthritis ◽  
Type I ◽  
Type I Ifn ◽  
Regulatory Factor ◽  
Interferon Regulatory Factor 3 ◽  
Responsive Gene

ABSTRACT We recently discovered a critical role for type I interferon (IFN) in the development of murine Lyme arthritis. Borrelia burgdorferi-mediated induction of IFN-responsive genes by bone marrow-derived macrophages (BMDMs) was dependent upon a functional type I IFN receptor but independent of Toll-like receptor 2 (TLR2), TLR4, TLR9, and the adapter molecule MyD88. We now demonstrate that induction of the IFN transcriptional profile in B. burgdorferi-stimulated BMDMs occurs independently of the adapter TRIF and of the cytoplasmic sensor NOD2. In contrast, B. burgdorferi-induced transcription of these genes was dependent upon a rapid STAT1 feedback amplification pathway. IFN profile gene transcription was IRF3 dependent but did not utilize B. burgdorferi-derived DNA or DNase-sensitive ligands. Instead, IFN-responsive gene expression could be induced by B. burgdorferi-derived RNA. Interferon regulatory factor 3 (IRF3)-dependent IFN profile gene transcription was also induced by sonicated bacteria, by the lipoprotein OspA, and by factors released into the BSKII medium during culture of B. burgdorferi. The IFN-stimulatory activity of B. burgdorferi culture supernatants was not destroyed by nuclease treatment. Nuclease digestion also had no effect on IFN profile induction mediated by sonicated B. burgdorferi. Thus, B. burgdorferi-derived RNA, OspA, and non-nucleic acid ligands present in both sonicated bacteria and B. burgdorferi culture medium contribute to type I IFN-responsive gene induction. These findings suggest that B. burgdorferi invasion of joint tissue and the resultant type I IFN induction associated with Lyme arthritis development may involve multiple triggering ligands.

scholarly journals The X proteins of bornaviruses interfere with type I interferon signalling

2013 ◽  
Vol 94 (2) ◽  
pp. 263-269 ◽  
Author(s):  
Jonas Johansson Wensman ◽  
Muhammad Munir ◽  
Srinivas Thaduri ◽  
Katarina Hörnaeus ◽  
Muhammad Rizwan ◽  
...  
Keyword(s):  
Type I Interferon ◽  
Rna Virus ◽  
Luciferase Reporter ◽  
Type I ◽  
Type I Ifn ◽  
X Protein ◽  
Wide Range ◽  
Reporter Assays ◽  
Interferon Signalling

Borna disease virus (BDV) is a neurotropic, negative-stranded RNA virus causing persistent infection and progressive neurological disorders in a wide range of warm-blooded animals. The role of the small non-structural X protein in viral pathogenesis is not completely understood. Here we investigated whether the X protein of BDV and avian bornavirus (ABV) interferes with the type I interferon (IFN) system, similar to other non-structural proteins of negative-stranded RNA viruses. In luciferase reporter assays, we found that the X protein of various bornaviruses interfered with the type I IFN system at all checkpoints investigated, in contrast to previously reported findings, resulting in reduced type I IFN secretion.

scholarly journals Pepscan Mapping of Viral Hemorrhagic Septicemia Virus Glycoprotein G Major Lineal Determinants Implicated in Triggering Host Cell Antiviral Responses Mediated by Type I Interferon

2010 ◽  
Vol 84 (14) ◽  
pp. 7140-7150 ◽  
Author(s):  
V. Chico ◽  
A. Martinez-Lopez ◽  
M. Ortega-Villaizan ◽  
A. Falco ◽  
L. Perez ◽  
...  
Keyword(s):  
Immune Responses ◽  
Protective Antigen ◽  
Type I Interferon ◽  
Viral Hemorrhagic Septicemia Virus ◽  
Type I ◽  
Type I Ifn ◽  
Viral Glycoprotein ◽  
Antiviral Responses ◽  
Viral Hemorrhagic Septicemia ◽  
Glycoprotein G

ABSTRACT Surface glycoproteins of enveloped virus are potent elicitors of type I interferon (IFN)-mediated antiviral responses in a way that may be independent of the well-studied genome-mediated route. However, the viral glycoprotein determinants responsible for initiating the IFN response remain unidentified. In this study, we have used a collection of 60 synthetic 20-mer overlapping peptides (pepscan) spanning the full length of glycoprotein G (gpG) of viral hemorrhagic septicemia virus (VHSV) to investigate what regions of this protein are implicated in triggering the type I IFN-associated immune responses. Briefly, two regions with ability to increase severalfold the basal expression level of the IFN-stimulated mx gene and to restrict the spread of virus among responder cells were mapped to amino acid residues 280 to 310 and 340 to 370 of the gpG protein of VHSV. In addition, the results obtained suggest that an interaction between VHSV gpG and integrins might trigger the host IFN-mediated antiviral response after VHSV infection. Since it is known that type I IFN plays an important role in determining/modulating the protective-antigen-specific immune responses, the identification of viral glycoprotein determinants directly implicated in the type I IFN induction might be of special interest for designing new adjuvants and/or more-efficient and cost-effective viral vaccines as well as for improving our knowledge on how to stimulate the innate immune system.

scholarly journals Porcine Reproductive and Respiratory Syndrome Virus nsp11 Antagonizes Type I Interferon Signaling by Targeting IRF9

2019 ◽  
Vol 93 (15) ◽  
Author(s):  
Dang Wang ◽  
Jiyao Chen ◽  
Chaoliang Yu ◽  
Xinyu Zhu ◽  
Shangen Xu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Type I Interferon ◽  
Nonstructural Protein ◽  
Interferon Regulatory Factor ◽  
Respiratory Syndrome Virus ◽  
Type I ◽  
Cell Cytotoxicity ◽  
Type I Ifn ◽  
Regulatory Factor ◽  
Transcription Factor Complex

ABSTRACT Porcine reproductive and respiratory syndrome virus (PRRSV) is an arterivirus from the Nidovirales order that causes reproductive failure and respiratory disease in pigs and poses a constant threat to the global pig industry. The PRRSV-encoded nonstructural protein 11 (nsp11) is a nidovirus-specific endoribonuclease (NendoU) that is conserved throughout the Arteriviridae and Coronaviridae families. Previously, our research and that of others demonstrated that PRRSV nsp11 inhibits type I interferon (IFN) production through NendoU activity-dependent mechanisms. Here, we found that PRRSV nsp11 also inhibited IFN-stimulated response element (ISRE) promoter activity and subsequent transcription of IFN-stimulated genes (ISGs). Detailed analysis showed that nsp11 targeted interferon regulatory factor 9 (IRF9), but not transducer and activator of transcription 1 (STAT1) or STAT2, key molecules in the type I IFN signaling pathway. Furthermore, the nsp11-IRF9 interaction impaired the formation and nuclear translocation of the transcription factor complex IFN-stimulated gene factor 3 (ISGF3) in both nsp11-overexpressed and PRRSV-infected cells. Importantly, nsp11 mutations (H129A, H144A, and K173A) that ablate NendoU activity or its cell cytotoxicity also interacted with IRF9 and retained the ability to block IFN signaling, indicating that the nsp11-IRF9 interaction is independent of NendoU activity or cell cytotoxicity of nsp11. Taking the results together, our study demonstrated that PRRSV nsp11 antagonizes type I IFN signaling by targeting IRF9 via a NendoU activity-independent mechanism, and this report describes a novel strategy evolved by PRRSV to counteract host innate antiviral responses, revealing a potential new function for PRRSV nsp11 in type I IFN signaling. IMPORTANCE The nidovirus-specific endoribonuclease (NendoU) encoded by PRRSV nonstructural protein 11 (nsp11) is a unique NendoU of nidoviruses that infect vertebrates; thus, it is an attractive target for the development of antinidovirus drugs. Previous studies have revealed that the NendoU of nidoviruses, including porcine reproductive and respiratory syndrome virus (PRRSV) and human coronavirus 229E (HCoV-229E), acts as a type I interferon (IFN) antagonist. Here, for the first time, we demonstrated that overexpression of PRRSV nsp11 also inhibits IFN signaling by targeting the C-terminal interferon regulatory factor (IRF) association domain of IRF9. This interaction impaired the ability of IRF9 to form the transcription factor complex IFN-stimulated gene factor 3 (ISGF3) and to act as a signaling protein of IFN signaling. Collectively, our data identify IRF9 as a natural target of PRRSV NendoU and reveal a novel mechanism evolved by an arterivirus to counteract innate immune signaling.

scholarly journals Antibodies against type-I Interferon: detection and association with severe clinical outcome in COVID-19 patients

2021 ◽  
Author(s):  
David Goncalves ◽  
Mehdi Mezidi ◽  
Paul Bastard ◽  
Magali Perret ◽  
Kahina Saker ◽  
...  
Keyword(s):  
Clinical Characteristics ◽  
Type I Interferon ◽  
Clinical Course ◽  
University Hospital ◽  
Type I ◽  
Type I Ifn ◽  
Type I Ifns ◽  
Recombinant Type ◽  
Circulating Autoantibodies

Objectives Impairment of type I interferon (IFN-I) immunity has been reported in critically ill COVID-19 patients. This defect can be explained by the presence of circulating autoantibodies against IFN-I. We set out to improve the detection and the quantification of such antibodies (Abs) in a cohort of severe Covid-19 patients, in an effort to better document the prevalence of these Abs as the pandemics evolves and how they correlate with the clinical course of the disease. Methods Anti-IFN-a Abs was investigated 84 critical COVID-19 patients who were admitted to ICU at the Lyon University Hospital, France with a commercially available kit (Thermo-Fisher). Results Twenty-one patients out of 84 (25%) had anti-IFNa2 Ab above cut-off (>34ng/mL) in sera. A neutralizing activity against IFN-a2 was evidenced in 15 of them, suggesting that 18% of patients were positive for neutralizing anti-IFN-a and -w auto-Abs. In addition, in most of patients with neutralizing IFN-I Abs, we noticed an impairment of the IFN-I response. However, we did not find any difference in terms of clinical characteristics or outcome between critical COVID-19 patients with or without neutralizing anti-IFN-a2 auto-Abs in these conditions. Finally, we detected anti-type I IFN auto-Abs in sera of COVID-19 patients were detected throughout the ICU stay. Conclusions We report that 18% of severe COVID-19 patients were positive for these Anti-Type-I IFN Abs, confirming the detrimental role of these Abs on the antiviral response. Our results further support the use of recombinant type I IFNs not targeted by the auto-Abs (e.g., IFN-b) in COVID-19 patients with an impaired IFN-I response.

The role of interferon regulatory factor 7 in the pathogenicity and immunogenicity of rabies virus in a mouse model

2021 ◽  
Vol 102 (10) ◽  
Author(s):  
Caiqian Wang ◽  
Lei Lv ◽  
Qiong Wu ◽  
Zongmei Wang ◽  
Zhaochen Luo ◽  
...  
Keyword(s):  
Mouse Model ◽  
Rabies Virus ◽  
Plasma Cells ◽  
Early Stage ◽  
Interferon Regulatory Factor ◽  
Type I ◽  
Type I Ifn ◽  
Regulatory Factor ◽  
Interferon Regulatory Factor 7

Rabies is a zoonotic disease caused by the rabies virus (RABV). RABV can lead to fatal encephalitis and is still a serious threat in most parts of the world. Interferon regulatory factor 7 (IRF7) is the main transcriptional regulator of type I IFN, and it is crucial for the induction of IFNα/β and the type I IFN-dependent immune response. In this study, we focused on the role of IRF7 in the pathogenicity and immunogenicity of RABV using an IRF7-/- mouse model. The results showed that the absence of IRF7 made mice more susceptible to RABV, because IRF7 restricted the replication of RABV in the early stage of infection. IRF7 deficiency affected the recruitment of plasmacytoid dendritic cells to the draining lymph nodes (dLNs), reduced the production of type I IFN and expression of IFN-stimulated genes. Furthermore, we found that the ability to produce specific RABV-neutralizing antibody was impaired in IRF7-/- mice. Consistently, IRF7 deficiency affected the recruitment of germinal-centre B cells to dLNs, and the generation of plasma cells and RABV-specific antibody secreting cells. Moreover, the absence of IRF7 downregulated the induction of IFN-γ and reduced type 1 T helper cell (Th1)-dependent antibody production. Collectively, our findings demonstrate that IRF7 promotes humoral immune responses and compromises the pathogenicity of RABV in a mouse model.

scholarly journals STAT3 Regulates the Type I IFN-Mediated Antiviral Response by Interfering with the Nuclear Entry of STAT1

2019 ◽  
Vol 20 (19) ◽  
pp. 4870 ◽  
Author(s):  
Huanru Wang ◽  
Meng Yuan ◽  
Shuaibo Wang ◽  
Li Zhang ◽  
Rui Zhang ◽  
...  
Keyword(s):  
Enterovirus 71 ◽  
Antiviral Response ◽  
Type I ◽  
Type I Ifn ◽  
Nuclear Entry ◽  
Protein Levels ◽  
Antiviral Responses ◽  
Importin Α ◽  
The Central Nervous System

Signal transducer and activator of transcription 3 (STAT3) is a multifunctional factor that regulates inflammation and immunity. Knowledge of its regulatory mechanisms is very limited. Here, we showed that enterovirus 71 (EV71) infection induced the phosphorylation of STAT3 and the expression of its downstream inflammatory regulators. Knockdown of STAT3 with siRNAs significantly restricted viral RNA and protein levels, and also reduced viral titers. With further investigation, we found that importin α family member Karyopherin-α1 (KPNA1) was employed by both STAT1 and STAT3 for their nuclear import. The phosphorylated and un-phosphorylated STAT3 competed with STAT1 for binding to the decreased KPNA1 post infection and repressed downstream ISG expression. STAT3 knockdown alleviated the repressed type I IFN-mediated antiviral response upon infection and led to decreased viral replication. Taken together, our data suggested the role of STAT3 in maintaining the balance of inflammation and antiviral responses in the central nervous system (CNS) upon infection.

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