201
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Enesa K, Ordureau A, Smith H, Barford D, Cheung PCF, Patterson-Kane J, Arthur JSC, Cohen P. Pellino1 is required for interferon production by viral double-stranded RNA. J Biol Chem 2012; 287:34825-35. [PMID: 22902624 PMCID: PMC3464584 DOI: 10.1074/jbc.m112.367557] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 08/13/2012] [Indexed: 12/24/2022] Open
Abstract
Viral double-stranded RNA, a ligand for Toll-like Receptor 3 (TLR3) and the cytoplasmic RNA receptors RIG1 and MDA5, activate a signaling network in which the IKK-related protein kinase TBK1 phosphorylates the transcription factor Interferon Regulatory Factor 3 (IRF3) and the E3 ubiquitin ligase Pellino1. IRF3 then translocates to the nucleus where it stimulates transcription of the interferonβ (IFNβ) gene, but the function of Pellino1 in this pathway is unknown. Here, we report that myeloid cells and embryonic fibroblasts from knock-in mice expressing an E3 ligase-deficient mutant of Pellino1 produce reduced levels of IFNβ mRNA and secrete much less IFNβ in response to viral double-stranded RNA because the interaction of IRF3 with the IFNβ promoter is impaired. These results identify Pellino1 as a novel component of the signal transduction network by which viral double-stranded RNA stimulates IFNβ gene transcription.
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MESH Headings
- Active Transport, Cell Nucleus
- Animals
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- DEAD Box Protein 58
- DEAD-box RNA Helicases/genetics
- DEAD-box RNA Helicases/metabolism
- Embryo, Mammalian/cytology
- Embryo, Mammalian/metabolism
- Fibroblasts/cytology
- Fibroblasts/metabolism
- Gene Knock-In Techniques
- Interferon Regulatory Factor-3/genetics
- Interferon Regulatory Factor-3/metabolism
- Interferon-Induced Helicase, IFIH1
- Interferon-beta/biosynthesis
- Interferon-beta/genetics
- Mice
- Mice, Transgenic
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Promoter Regions, Genetic/physiology
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- RNA, Double-Stranded/genetics
- RNA, Double-Stranded/metabolism
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Signal Transduction/physiology
- Toll-Like Receptor 3/genetics
- Toll-Like Receptor 3/metabolism
- Transcription, Genetic/physiology
- Ubiquitin-Protein Ligases
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Affiliation(s)
| | | | | | - David Barford
- the Institute of Cancer Research, London SW36JB, United Kingdom
| | | | - Janet Patterson-Kane
- the Institute of Infection, Immunity, and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, G611QH, United Kingdom
| | | | - Philip Cohen
- From the MRC Protein Phosphorylation Unit and
- Scottish Institute for Cell Signaling, Sir James Black Centre, University of Dundee, DD15EH, United Kingdom
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202
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Critical role for interferon regulatory factor 3 (IRF-3) and IRF-7 in type I interferon-mediated control of murine norovirus replication. J Virol 2012; 86:13515-23. [PMID: 23035219 DOI: 10.1128/jvi.01824-12] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Human noroviruses (HuNoV) are the major cause of epidemic, nonbacterial gastroenteritis in the world. The short course of HuNoV-induced symptoms has implicated innate immunity in control of norovirus (NoV) infection. Studies using murine norovirus (MNV) confirm the importance of innate immune responses during NoV infection. Type I alpha and beta interferons (IFN-α/β) limit HuNoV replicon function, restrict MNV replication in cultured cells, and control MNV replication in vivo. Therefore, the cell types and transcription factors involved in antiviral immune responses and IFN-α/β-mediated control of NoV infection are important to define. We used mice with floxed alleles of the IFNAR1 chain of the IFN-α/β receptor to identify cells expressing lysozyme M or CD11c as cells that respond to IFN-α/β to restrict MNV replication in vivo. Furthermore, we show that the transcription factors IRF-3 and IRF-7 work in concert to initiate unique and overlapping antiviral responses to restrict MNV replication in vivo. IRF-3 and IRF-7 restrict MNV replication in both cultured macrophages and dendritic cells, are required for induction of IFN-α/β in macrophages but not dendritic cells, and are dispensable for the antiviral effects of IFN-α/β that block MNV replication. These studies suggest that expression of the IFN-α/β receptor on macrophages/neutrophils and dendritic cells, as well as of IRF-3 and IRF-7, is critical for innate immune responses to NoV infection.
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203
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Yin Z, Dai J, Deng J, Sheikh F, Natalia M, Shih T, Lewis-Antes A, Amrute SB, Garrigues U, Doyle S, Donnelly RP, Kotenko SV, Fitzgerald-Bocarsly P. Type III IFNs are produced by and stimulate human plasmacytoid dendritic cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 189:2735-45. [PMID: 22891284 PMCID: PMC3579503 DOI: 10.4049/jimmunol.1102038] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Plasmacytoid dendritic cells (pDC) are rare cells found in peripheral blood and lymphoid tissues. pDC are considered to be "professional" type I IFN-producing cells and produce 10- to 100-fold more IFN-α than other cell types in response to enveloped viruses or synthetic TLR7 and TLR9 agonists. In this study, purified pDC were found to express high levels of IFN-λ receptor mRNA, as well as cell-surface IFN-λ receptor. We have developed intracellular flow cytometry assays using Abs to IFN-λ1/3 or -λ2 to assess the expression of IFN-λ proteins by pDC. We observed that a subset of human pDC expresses only intracellular IFN-α, whereas another subset produces both IFN-α and IFN-λ after stimulation with virus or the TLR9 agonist, CpG A; the cells that coexpressed IFN-α and IFN-λ were the cells with the highest levels of IFN-α expression. Ab cross-linking of CD4 or CD303 molecules on pDC inhibited both HSV-induced IFN-λ and IFN-α production. Like the production of IFN-α, the HSV-induced IFN-λ production in pDC was mediated through TLR9 and independent of virus replication. Exogenous IFN-λ treatment of pDC resulted in increased virus-induced expression of both IFN-α and IFN-λ. In addition, both exogenous IFN-λ and -α inhibited dexamethasone-induced apoptosis of pDC. We conclude that pDC are major producers of IFN-λ1 and -λ2 in response to viral stimulation and also express functional receptors for this cytokine. Thus, IFN-λ can serve as an autocrine signal to strengthen the antiviral response of pDC by increasing IFN-α and IFN-λ production, resulting in prolonged pDC survival.
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Affiliation(s)
- Zhiwei Yin
- Department of Pathology and Laboratory Medicine, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, NJ 07103, USA
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204
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van de Sandt CE, Kreijtz JHCM, Rimmelzwaan GF. Evasion of influenza A viruses from innate and adaptive immune responses. Viruses 2012; 4:1438-76. [PMID: 23170167 PMCID: PMC3499814 DOI: 10.3390/v4091438] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/10/2012] [Accepted: 08/22/2012] [Indexed: 12/16/2022] Open
Abstract
The influenza A virus is one of the leading causes of respiratory tract infections in humans. Upon infection with an influenza A virus, both innate and adaptive immune responses are induced. Here we discuss various strategies used by influenza A viruses to evade innate immune responses and recognition by components of the humoral and cellular immune response, which consequently may result in reduced clearing of the virus and virus-infected cells. Finally, we discuss how the current knowledge about immune evasion can be used to improve influenza A vaccination strategies.
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Affiliation(s)
- Carolien E van de Sandt
- Department of Virology, ErasmusMC, Dr. Molewaterplein 50, 3015 GE, Rotterdam, The Netherlands.
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205
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Günel A. Modelling the interactions between TLR4 and IFNβ pathways. J Theor Biol 2012; 307:137-48. [PMID: 22575970 DOI: 10.1016/j.jtbi.2012.04.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 04/17/2012] [Accepted: 04/18/2012] [Indexed: 02/06/2023]
Abstract
Bacterial lipopolysaccharide (LPS) association with their connate receptor TLR4 triggers Type I interferon signaling cascade through its MyD88 independent downstream. Compared to plethora of reported empirical data on both TLR4 and Type I interferon pathways, there is no known model to decipher crosstalk mechanisms between these two crucial innate immune pathogen activated pathways regulating vital transcriptional factors such as nuclear factor-κB (NFκB), IFNβ, the interferon-stimulated gene factor-3 (ISGF3) and an important cancer drug target protein kinase-R (PKR). Innate immune system is based on a sensitive balance of intricate interactions. In elucidating these interactions, in silico integration of pathways has great potential. Attempts confined to single pathway may not be effective in truly addressing source of real systems behavior. This is the first report combining toll-like receptor-4 (TLR4) and interferon beta (IFNβ) pathways in a single in silico model, analyzing their interactions, pinpointing the source of delay in PKR late phase activity and limiting the transcription of IFN and PKR by using a method including an statistical physics technique in reaction equations. The model quite successfully recapitulates published interferon regulatory factor-3 (IRF3) and IFNβ data from mouse macrophages and PKR data from mouse embryonic fibroblast cell lines. The simulations end up with an estimate of IRF3, IFNβ, ISGF3 dose dependent profiles mimicking nonlinear dose response characteristic of the system. Involvement of concomitant PKR downstream can unravel elusive mechanisms in specific profiles like NFκB regulation.
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Affiliation(s)
- Aylin Günel
- Istanbul Technical University Informatics Institute, Maslak, 34469, Istanbul, Turkiye.
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206
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Patel AA, Lee-Lewis H, Hughes-Hanks J, Lewis CA, Anderson DM. Opposing roles for interferon regulatory factor-3 (IRF-3) and type I interferon signaling during plague. PLoS Pathog 2012; 8:e1002817. [PMID: 22911267 PMCID: PMC3406097 DOI: 10.1371/journal.ppat.1002817] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Accepted: 06/10/2012] [Indexed: 11/25/2022] Open
Abstract
Type I interferons (IFN-I) broadly control innate immunity and are typically transcriptionally induced by Interferon Regulatory Factors (IRFs) following stimulation of pattern recognition receptors within the cytosol of host cells. For bacterial infection, IFN-I signaling can result in widely variant responses, in some cases contributing to the pathogenesis of disease while in others contributing to host defense. In this work, we addressed the role of type I IFN during Yersinia pestis infection in a murine model of septicemic plague. Transcription of IFN-β was induced in vitro and in vivo and contributed to pathogenesis. Mice lacking the IFN-I receptor, Ifnar, were less sensitive to disease and harbored more neutrophils in the later stage of infection which correlated with protection from lethality. In contrast, IRF-3, a transcription factor commonly involved in inducing IFN-β following bacterial infection, was not necessary for IFN production but instead contributed to host defense. In vitro, phagocytosis of Y. pestis by macrophages and neutrophils was more effective in the presence of IRF-3 and was not affected by IFN-β signaling. This activity correlated with limited bacterial growth in vivo in the presence of IRF-3. Together the data demonstrate that IRF-3 is able to activate pathways of innate immunity against bacterial infection that extend beyond regulation of IFN-β production. Type I interferons (IFN-I) broadly stimulate innate immunity against viral, bacterial and parasitic pathogens. Many bacterial pathogens induce IFN-I through phosphorylation of Interferon Regulatory Factor 3 (IRF-3) allowing it to bind promoters containing Interferon Stimulated Response Elements (ISRE) which include IFN-β and pro-inflammatory cytokines and chemokines. Secreted IFN-β is taken up by the IFN-αβ receptor (IFNAR), triggering activation of the JAK-STAT pathway which also activates ISRE-containing genes. In this work, we have discovered a novel anti-bacterial function of IRF-3. We show that the respiratory pathogen, Yersinia pestis, the causative agent of plague, activates IRF-3 and the IFN-I response and that these two events cause opposite outcomes in the host. While IRF-3 is necessary for an early stage of phagocytosis, IFNAR signaling promotes the infection and may directly contribute to neutrophil depletion during infection. These results demonstrate that an IFN-independent function of IRF-3 is important to host defense against bacterial infection.
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Affiliation(s)
- Ami A. Patel
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, United States of America
- Laboratory for Infectious Disease Research, University of Missouri, Columbia, Missouri, United States of America
| | - Hanni Lee-Lewis
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, United States of America
- Laboratory for Infectious Disease Research, University of Missouri, Columbia, Missouri, United States of America
| | - Jennifer Hughes-Hanks
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, United States of America
| | - Craig A. Lewis
- Starling Enterprise, LLC, Columbia, Missouri, United States of America
| | - Deborah M. Anderson
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, United States of America
- Laboratory for Infectious Disease Research, University of Missouri, Columbia, Missouri, United States of America
- * E-mail:
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207
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Interferon response factors 3 and 7 protect against Chikungunya virus hemorrhagic fever and shock. J Virol 2012; 86:9888-98. [PMID: 22761364 DOI: 10.1128/jvi.00956-12] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chikungunya virus (CHIKV) infections can produce severe disease and mortality. Here we show that CHIKV infection of adult mice deficient in interferon response factors 3 and 7 (IRF3/7(-/-)) is lethal. Mortality was associated with undetectable levels of alpha/beta interferon (IFN-α/β) in serum, ∼50- and ∼10-fold increases in levels of IFN-γ and tumor necrosis factor (TNF), respectively, increased virus replication, edema, vasculitis, hemorrhage, fever followed by hypothermia, oliguria, thrombocytopenia, and raised hematocrits. These features are consistent with hemorrhagic shock and were also evident in infected IFN-α/β receptor-deficient mice. In situ hybridization suggested CHIKV infection of endothelium, fibroblasts, skeletal muscle, mononuclear cells, chondrocytes, and keratinocytes in IRF3/7(-/-) mice; all but the latter two stained positive in wild-type mice. Vaccination protected IRF3/7(-/-) mice, suggesting that defective antibody responses were not responsible for mortality. IPS-1- and TRIF-dependent pathways were primarily responsible for IFN-α/β induction, with IRF7 being upregulated >100-fold in infected wild-type mice. These studies suggest that inadequate IFN-α/β responses following virus infection can be sufficient to induce hemorrhagic fever and shock, a finding with implications for understanding severe CHIKV disease and dengue hemorrhagic fever/dengue shock syndrome.
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208
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Hundeshagen A, Hecker M, Paap BK, Angerstein C, Kandulski O, Fatum C, Hartmann C, Koczan D, Thiesen HJ, Zettl UK. Elevated type I interferon-like activity in a subset of multiple sclerosis patients: molecular basis and clinical relevance. J Neuroinflammation 2012; 9:140. [PMID: 22727118 PMCID: PMC3464734 DOI: 10.1186/1742-2094-9-140] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 06/22/2012] [Indexed: 12/26/2022] Open
Abstract
Background A subset of patients with multiple sclerosis (MS) shows an increased endogenous IFN-like activity before initiation of IFN-beta treatment. The molecular basis of this phenomenon and its relevance to predict individual therapy outcomes are not yet fully understood. We studied the expression patterns of these patients, the prognostic value of an elevated IFN-like activity, and the gene regulatory effects of exogenously administered IFN-beta. Methods Microarray gene expression profiling was performed for 61 MS patients using peripheral blood mononuclear cells obtained before and after 1 month of IFN-beta therapy. Expression levels of genes involved in pathways either inducing or being activated by IFN-beta were compared between patients with high (MX1high cohort) and low (MX1low cohort) endogenous IFN-like activity. Patients were followed for 5 years and relapses as well as progression on the expanded disability status scale (EDSS) were documented. Results Before the start of therapy, 11 patients presented elevated mRNA levels of IFN-stimulated genes indicative of a relatively high endogenous IFN-like activity (MX1high). In these patients, pathogen receptors (for example, TLR7, RIG-I and IFIH1) and transcription factors were also expressed more strongly, which could be attributed to an overactivity of IFN-stimulated gene factor 3 (ISGF3, a complex formed by STAT1, STAT2 and IFN regulatory factor 9). After 1 month of IFN-beta therapy, the expression of many pathway genes was significantly induced in MX1low patients, but remained unaltered in MX1high patients. During follow-up, relapse rate and changes in EDSS were comparable between both patient groups, with differences seen between different types of IFN-beta drug application. Conclusions Therapeutic IFN-beta induces the transcription of several genes involved in IFN-related pathways. In a subgroup of MS patients, the expression of these genes is already increased before therapy initiation, possibly driven by an overexpression of ISGF3. Patients with high and low endogenous IFN-like activity showed similar clinical long-term courses of disease. Different results were obtained for different IFN-beta drug preparations, and this merits further investigation.
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Affiliation(s)
- Alexander Hundeshagen
- Department of Neurology, Division of Neuroimmunology, University of Rostock, Germany
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209
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Recent progress in studies of arterivirus- and coronavirus-host interactions. Viruses 2012; 4:980-1010. [PMID: 22816036 PMCID: PMC3397358 DOI: 10.3390/v4060980] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 05/30/2012] [Accepted: 06/14/2012] [Indexed: 12/15/2022] Open
Abstract
Animal coronaviruses, such as infectious bronchitis virus (IBV), and arteriviruses, such as porcine reproductive and respiratory syndrome virus (PRRSV), are able to manifest highly contagious infections in their specific native hosts, thereby arising in critical economic damage to animal industries. This review discusses recent progress in studies of virus-host interactions during animal and human coronavirus and arterivirus infections, with emphasis on IBV-host cell interactions. These interactions may be directly involved in viral replication or lead to the alteration of certain signaling pathways, such as cell stress response and innate immunity, to facilitate viral replication and pathogenesis.
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210
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Yang Y, Shaffer AL, Emre NT, Ceribelli M, Zhang M, Wright G, Xiao W, Powell J, Platig J, Kohlhammer H, Young RM, Zhao H, Yang Y, Xu W, Buggy JJ, Balasubramanian S, Mathews LA, Shinn P, Guha R, Ferrer M, Thomas C, Waldmann TA, Staudt LM. Exploiting synthetic lethality for the therapy of ABC diffuse large B cell lymphoma. Cancer Cell 2012; 21:723-37. [PMID: 22698399 PMCID: PMC4059833 DOI: 10.1016/j.ccr.2012.05.024] [Citation(s) in RCA: 402] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 03/13/2012] [Accepted: 05/22/2012] [Indexed: 12/30/2022]
Abstract
Knowledge of oncogenic mutations can inspire therapeutic strategies that are synthetically lethal, affecting cancer cells while sparing normal cells. Lenalidomide is an active agent in the activated B cell-like (ABC) subtype of diffuse large B cell lymphoma (DLBCL), but its mechanism of action is unknown. Lenalidomide kills ABC DLBCL cells by augmenting interferon β (IFNβ) production, owing to the oncogenic MYD88 mutations in these lymphomas. In a cereblon-dependent fashion, lenalidomide downregulates IRF4 and SPIB, transcription factors that together prevent IFNβ production by repressing IRF7 and amplify prosurvival NF-κB signaling by transactivating CARD11. Blockade of B cell receptor signaling using the BTK inhibitor ibrutinib also downregulates IRF4 and consequently synergizes with lenalidomide in killing ABC DLBCLs, suggesting attractive therapeutic strategies.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Adenine/analogs & derivatives
- Animals
- Antineoplastic Combined Chemotherapy Protocols/therapeutic use
- Blotting, Western
- Cell Line, Tumor
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Female
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic/drug effects
- Gene Regulatory Networks/drug effects
- Humans
- Interferon Regulatory Factors/genetics
- Interferon Regulatory Factors/metabolism
- Interferon-beta/genetics
- Interferon-beta/metabolism
- Interferon-beta/pharmacology
- Lenalidomide
- Lymphoma, Large B-Cell, Diffuse/drug therapy
- Lymphoma, Large B-Cell, Diffuse/genetics
- Lymphoma, Large B-Cell, Diffuse/pathology
- Mice
- Mice, Inbred NOD
- Mice, SCID
- NF-kappa B/genetics
- NF-kappa B/metabolism
- Peptide Hydrolases/genetics
- Peptide Hydrolases/metabolism
- Piperidines
- Pyrazoles/administration & dosage
- Pyrimidines/administration & dosage
- RNA Interference
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction/drug effects
- Thalidomide/administration & dosage
- Thalidomide/analogs & derivatives
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Tumor Burden/drug effects
- Tumor Burden/genetics
- Ubiquitin-Protein Ligases
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Yibin Yang
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Arthur L. Shaffer
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - N.C. Tolga Emre
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Michele Ceribelli
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Meili Zhang
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - George Wright
- Biometric Research Branch, National Cancer Institute, Rockville, MD, USA
| | - Wenming Xiao
- Bioinformatics and Molecular Analysis Section, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, MD, USA
| | - John Powell
- Bioinformatics and Molecular Analysis Section, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, MD, USA
| | - John Platig
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- University of Maryland, Institute for Research in Electronics and Applied Physics. College Park, MD, USA
| | - Holger Kohlhammer
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ryan M. Young
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Hong Zhao
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yandan Yang
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Weihong Xu
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | | | | | - Lesley A. Mathews
- National Center for Advancing Translational Sciences, Bethesda, MD, USA
| | - Paul Shinn
- National Center for Advancing Translational Sciences, Bethesda, MD, USA
| | - Rajarshi Guha
- National Center for Advancing Translational Sciences, Bethesda, MD, USA
| | - Marc Ferrer
- National Center for Advancing Translational Sciences, Bethesda, MD, USA
| | - Craig Thomas
- National Center for Advancing Translational Sciences, Bethesda, MD, USA
| | - Thomas A. Waldmann
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Louis M. Staudt
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- Corresponding author: Louis M. Staudt, MD, PhD, 9000 Rockville Pike, Building 10, Room 4N114, Bethesda, MD 20892, 301-402-1892, Fax: 301-496-9956,
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211
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Yue X, Wang H, Zhao F, Liu S, Wu J, Ren W, Zhu Y. Hepatitis B Virus-Induced Calreticulin Protein Is Involved in IFN Resistance. THE JOURNAL OF IMMUNOLOGY 2012; 189:279-86. [DOI: 10.4049/jimmunol.1103405] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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212
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Lo CC, Schwartz JA, Johnson DJ, Yu M, Aidarus N, Mujib S, Benko E, Hyrcza M, Kovacs C, Ostrowski MA. HIV delays IFN-α production from human plasmacytoid dendritic cells and is associated with SYK phosphorylation. PLoS One 2012; 7:e37052. [PMID: 22693567 PMCID: PMC3365039 DOI: 10.1371/journal.pone.0037052] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 04/16/2012] [Indexed: 12/12/2022] Open
Abstract
Plasmacytoid dendritic cells (pDC) are the major producers of type I interferons (IFNs) in humans and rapidly produce IFN-α in response to virus exposure. Although HIV infection is associated with pDC activation, it is unclear why the innate immune response is unable to effectively control viral replication. We systematically compared the effect of HIV, Influenza, Sendai, and HSV-2 at similar target cell multiplicity of infection (M.O.I.) on human pDC function. We found that Influenza, Sendai, HSV-2 and imiquimod are able to rapidly induce IFN-α production within 4 hours to maximal levels, whereas HIV had a delayed induction that was maximal only after 24 hours. In addition, maximal IFN-α induction by HIV was at least 10 fold less than that of the other viruses in the panel. HIV also induced less TNF-α and MIP-1β but similar levels of IP-10 compared to other viruses, which was also mirrored by delayed upregulation of pDC activation markers CD83 and CD86. BDCA-2 has been identified as an inhibitory receptor on pDC, signaling through a pathway that involves SYK phosphorylation. We find that compared to Influenza, HIV induces the activation of the SYK pathway. Thus, HIV delays pDC IFN-α production and pDC activation via SYK phosphorylation, allowing establishment of viral populations.
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Affiliation(s)
- Calvin C. Lo
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Jordan A. Schwartz
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Dylan J. Johnson
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Monica Yu
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Nasra Aidarus
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Shariq Mujib
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Erika Benko
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Maple Leaf Medical Clinic, Toronto, Ontario, Canada
| | - Martin Hyrcza
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Colin Kovacs
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Maple Leaf Medical Clinic, Toronto, Ontario, Canada
| | - Mario A. Ostrowski
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Li Ka Shing Institute, St. Michael’s Hospital, Toronto, Ontario, Canada
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213
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Gough DJ, Messina NL, Clarke CJP, Johnstone RW, Levy DE. Constitutive type I interferon modulates homeostatic balance through tonic signaling. Immunity 2012; 36:166-74. [PMID: 22365663 DOI: 10.1016/j.immuni.2012.01.011] [Citation(s) in RCA: 335] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 01/16/2012] [Accepted: 01/31/2012] [Indexed: 02/07/2023]
Abstract
Interferons (IFNs) were discovered as cytokines induced during and protecting from viral infection. They have been documented to play essential roles in numerous physiological processes beyond antiviral and antimicrobial defense, including immunomodulation, cell cycle regulation, cell survival, and cell differentiation. Recent data have also uncovered a potentially darker side to IFN, including roles in inflammatory diseases, such as autoimmunity and diabetes. IFN can have effects in the absence of acute infection, highlighting a physiologic role for constitutive IFN. Type I IFNs are constitutively produced at vanishingly low quantities and yet exert profound effects, mediated in part through modulation of signaling intermediates required for responses to diverse cytokines. We review evidence for a yin-yang of IFN function through its role in modulating crosstalk between multiple cytokines by both feedforward and feedback regulation of common signaling intermediates and postulate a homeostatic role for IFN through tonic signaling in the absence of acute infection.
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Affiliation(s)
- Daniel J Gough
- New York University Medical Center, New York, NY 10016, USA
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214
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Differential impact of interferon regulatory factor 7 in initiation of the type I interferon response in the lymphocytic choriomeningitis virus-infected central nervous system versus the periphery. J Virol 2012; 86:7384-92. [PMID: 22514347 DOI: 10.1128/jvi.07090-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Interferon (IFN) regulatory factors (IRFs) are a family of transcription factors involved in regulating type I IFN genes and other genes participating in the early antiviral host response. To better understand the mechanisms involved in virus-induced central nervous system (CNS) inflammation, we studied the influence of IRF1, -3, -7, and -9 on the transcriptional activity of key genes encoding antiviral host factors in the CNS of mice infected with lymphocytic choriomeningitis virus (LCMV). A key finding is that neither IRF3 nor IRF7 is absolutely required for induction of a type I IFN response in the LCMV-infected CNS, whereas concurrent elimination of both factors markedly reduces the virus-induced host response. This is unlike the situation in the periphery, where deficiency of IRF7 almost eliminates the LCMV-induced production of the type I IFNs. This difference is seemingly related to the local environment, as peripheral production of type I IFNs is severely reduced in intracerebrally (i.c.) infected IRF7-deficient mice, which undergo a combined infection of the CNS and peripheral organs, such as spleen and lymph nodes. Interestingly, despite the redundancy of IRF7 in initiating the type I IFN response in the CNS, the response is not abolished in IFN-β-deficient mice, as might have been expected. Collectively, these data demonstrate that the early type I IFN response to LCMV infection in the CNS is controlled by a concerted action of IRF3 and -7. Consequently this work provides strong evidence for differential regulation of the type I IFN response in the CNS versus the periphery during viral infection.
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215
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Virus-activated interferon regulatory factor 7 upregulates expression of the interferon-regulated BST2 gene independently of interferon signaling. J Virol 2012; 86:3513-27. [PMID: 22301143 DOI: 10.1128/jvi.06971-11] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BST-2/tetherin is an interferon (IFN)-inducible host restriction factor that inhibits the release of many enveloped viruses and functions as a negative-feedback regulator of IFN production by plasmacytoid dendritic cells. Currently, mechanisms underlying BST2 transcriptional regulation by type I IFN remain largely unknown. Here, we demonstrate that the BST2 promoter is a secondary target of the IFN cascade and show that a single IRF binding site is sufficient to render this promoter responsive to IFN-α. Interestingly, expression of IRF-1 or virus-activated forms of IRF-3 and IRF-7 stimulated the BST2 promoter even under conditions where type I IFN signaling was inhibited. Indeed, vesicular stomatitis virus could directly upregulate BST-2 during infection of mouse embryonic fibroblasts through a process that required IRF-7 but was independent from the type I IFN cascade; however, in order to achieve optimal BST-2 induction, the type I IFN cascade needed to be engaged through activation of IRF-3. Furthermore, using human peripheral blood mononuclear cells, we show that BST-2 upregulation is part of an early intrinsic immune response since TLR8 and TLR3 agonists, known to trigger pathways that mediate activation of IRF proteins, could upregulate BST-2 prior to engagement of the type I IFN pathway. Collectively, our findings reveal that BST2 is activated by the same signals that trigger type I IFN production, outlining a regulatory mechanism ensuring that production of type I IFN and expression of a host restriction factor involved in the IFN negative-feedback loop are closely coordinated.
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216
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Robinson BA, Estep RD, Messaoudi I, Rogers KS, Wong SW. Viral interferon regulatory factors decrease the induction of type I and type II interferon during rhesus macaque rhadinovirus infection. J Virol 2012; 86:2197-211. [PMID: 22156526 PMCID: PMC3302421 DOI: 10.1128/jvi.05047-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 11/17/2011] [Indexed: 01/20/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus and rhesus macaque rhadinovirus (RRV), two closely related gammaherpesviruses, are unique in their expression of viral homologs of cellular interferon regulatory factors (IRFs), termed viral IRFs (vIRFs). To assess the role of vIRFs during de novo infection, we have utilized the bacterial artificial chromosome clone of wild-type RRV(17577) (WT(BAC) RRV) to generate a recombinant virus with all 8 of the vIRFs deleted (vIRF-ko RRV). The infection of primary rhesus fibroblasts and peripheral blood mononuclear cells (PBMCs) with vIRF-ko RRV resulted in earlier and increased induction of type I interferon (IFN) (IFN-α/β) and type II IFN (IFN-γ). Additionally, plasmacytoid dendritic cells maintained higher levels of IFN-α production in PBMC cultures infected with vIRF-ko RRV than in cultures infected with WT(BAC) RRV. Moreover, the nuclear accumulation of phosphorylated IRF-3, which is necessary for the induction of type I IFN, was also inhibited following WT(BAC) RRV infection. These findings demonstrate that during de novo RRV infection, vIRFs are inhibiting the induction of IFN at the transcriptional level, and one potential mechanism for this is the disruption of the activation and localization of IRF-3.
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Affiliation(s)
- Bridget A. Robinson
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, USA
| | - Ryan D. Estep
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, USA
| | - Ilhem Messaoudi
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, USA
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Beaverton, Oregon, USA
| | - Kelsey S. Rogers
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, USA
| | - Scott W. Wong
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, USA
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Beaverton, Oregon, USA
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217
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A single-amino-acid polymorphism in reovirus protein μ2 determines repression of interferon signaling and modulates myocarditis. J Virol 2011; 86:2302-11. [PMID: 22156521 DOI: 10.1128/jvi.06236-11] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Myocarditis is indicated as the second leading cause of sudden death in young adults. Reovirus induces myocarditis in neonatal mice, providing a tractable model system for investigation of this important disease. Alpha/beta-interferon (IFN-α/β) treatment improves cardiac function and inhibits viral replication in patients with chronic myocarditis, and the host IFN-α/β response is a determinant of reovirus strain-specific differences in induction of myocarditis. Virus-induced IFN-β stimulates a signaling cascade that establishes an antiviral state and further induces IFN-α/β through an amplification loop. Reovirus strain-specific differences in induction of and sensitivity to IFN-α/β are associated with the viral M1, L2, and S2 genes. The reovirus M1 gene-encoded μ2 protein is a strain-specific repressor of IFN-β signaling, providing one possible mechanism for the variation in resistance to IFN and induction of myocarditis between different reovirus strains. We report here that μ2 amino acid 208 determines repression of IFN-β signaling and modulates reovirus induction of IFN-β in cardiac myocytes. Moreover, μ2 amino acid 208 determines reovirus replication, both in initially infected cardiac myocytes and after viral spread, by regulating the IFN-β response. Amino acid 208 of μ2 also influences the cytopathic effect in cardiac myocytes after spread. Finally, μ2 amino acid 208 modulates myocarditis in neonatal mice. Thus, repression of IFN-β signaling mediated by reovirus μ2 amino acid 208 is a determinant of the IFN-β response, viral replication and damage in cardiac myocytes, and myocarditis. These results demonstrate that a single amino acid difference between viruses can dictate virus strain-specific differences in suppression of the host IFN-β response and, consequently, damage to the heart.
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218
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Sirois M, Robitaille L, Allary R, Shah M, Woelk CH, Estaquier J, Corbeil J. TRAF6 and IRF7 control HIV replication in macrophages. PLoS One 2011; 6:e28125. [PMID: 22140520 PMCID: PMC3225375 DOI: 10.1371/journal.pone.0028125] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 11/01/2011] [Indexed: 01/08/2023] Open
Abstract
The innate immune system recognizes virus infection and evokes antiviral responses which include producing type I interferons (IFNs). The induction of IFN provides a crucial mechanism of antiviral defense by upregulating interferon-stimulated genes (ISGs) that restrict viral replication. ISGs inhibit the replication of many viruses by acting at different steps of their viral cycle. Specifically, IFN treatment prior to in vitro human immunodeficiency virus (HIV) infection stops or significantly delays HIV-1 production indicating that potent inhibitory factors are generated. We report that HIV-1 infection of primary human macrophages decreases tumor necrosis factor receptor-associated factor 6 (TRAF6) and virus-induced signaling adaptor (VISA) expression, which are both components of the IFN signaling pathway controlling viral replication. Knocking down the expression of TRAF6 in macrophages increased HIV-1 replication and augmented the expression of IRF7 but not IRF3. Suppressing VISA had no impact on viral replication. Overexpression of IRF7 resulted in enhanced viral replication while knocking down IRF7 expression in macrophages significantly reduced viral output. These findings are the first demonstration that TRAF6 can regulate HIV-1 production and furthermore that expression of IRF7 promotes HIV-1 replication.
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Affiliation(s)
- Mélissa Sirois
- Department of Molecular Medicine, Infectious Disease Research Center, CHUL Research Center and Laval University, Québec, Québec, Canada
| | - Lynda Robitaille
- Department of Molecular Medicine, Infectious Disease Research Center, CHUL Research Center and Laval University, Québec, Québec, Canada
| | - Robin Allary
- Department of Molecular Medicine, Infectious Disease Research Center, CHUL Research Center and Laval University, Québec, Québec, Canada
| | - Mohak Shah
- Department of Electrical and Computer Engineering, Centre for Intelligent Machines, McGill University, Montreal, Québec, Canada
| | - Christopher H. Woelk
- Department of Medicine, University of California San Diego, San Diego, California, United States of America
| | - Jérôme Estaquier
- Department of Molecular Medicine, Infectious Disease Research Center, CHUL Research Center and Laval University, Québec, Québec, Canada
- CNRS FRE3235, Université René Descartes Paris, Paris, France
| | - Jacques Corbeil
- Department of Molecular Medicine, Infectious Disease Research Center, CHUL Research Center and Laval University, Québec, Québec, Canada
- * E-mail:
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219
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Abstract
For decades, type I IFNs have been considered indispensable and unique antiviral mediators for the activation of rapid innate antiviral protection. However, the recent discovery of type III IFNs is challenging this paradigm. Since their identification in 2002/2003 by two independent groups, type III IFNs or IFN-λs, also known as IL-28/29, have been the subject of increased study with consequent recognition of their importance in virology and immunology. Initial reports suggested that IFN-λs functionally resemble type I IFNs. Although IFN-λs and classical type I IFNs (IFN-α/β) utilize distinct receptor complexes for signaling, both types of IFNs activate similar intracellular signaling pathways and biological activities, including the ability to induce antiviral state in cells, and both type I and type III IFNs are induced by viral infection. However, different antiviral potency, pattern of their induction and differential tissue expression of their corresponding receptor subunits suggest that the type I and type III IFN antiviral systems do not merely duplicate each other. Recent studies have started to reveal unique biological activities of IFN-λs in and beyond innate antiviral immunity.
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Affiliation(s)
- Sergei V Kotenko
- Department of Biochemistry and Molecular Biology, University Hospital Cancer Center, New Jersey Medical School, University of Medicine and Dentistry, USA.
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220
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Kreijtz JHCM, Fouchier RAM, Rimmelzwaan GF. Immune responses to influenza virus infection. Virus Res 2011; 162:19-30. [PMID: 21963677 DOI: 10.1016/j.virusres.2011.09.022] [Citation(s) in RCA: 223] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 09/15/2011] [Accepted: 09/15/2011] [Indexed: 10/17/2022]
Abstract
Influenza viruses cause annual outbreaks of respiratory tract infection with attack rates of 5-10%. This means that humans are infected repeatedly with intervals of, on average, 10-20 years. Upon each infection subjects develop innate and adaptive immune responses which aim at clearing the infection. Strain-specific antibody responses are induced, which exert selective pressure on circulating influenza viruses and which drive antigenic drift of seasonal influenza viruses, especially in the hemagglutinin molecule. This antigenic drift necessitates updating of seasonal influenza vaccines regularly in order to match the circulating strains. Upon infection also virus-specific T cell responses are induced, including CD4+ T helper cells and CD8+ cytotoxic T cells. These cells are mainly directed to conserved proteins and therefore display cross-reactivity with a variety of influenza A viruses of different subtypes. T cell mediated immunity therefore may contribute to so-called heterosubtypic immunity and may afford protection against antigenically distinct, potentially pandemic influenza viruses. At present, novel viral targets are identified that may help to develop broad-protective vaccines. Here we review the various arms of the immune response to influenza virus infections and their viral targets and discuss the possibility of developing universal vaccines. The development of such novel vaccines would imply that also new immune correlates of protection need to be established in order to facilitate assessment of vaccine efficacy.
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Affiliation(s)
- J H C M Kreijtz
- Department of Virology, Erasmus MC, Rotterdam, The Netherlands
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221
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Myxoma virus induces type I interferon production in murine plasmacytoid dendritic cells via a TLR9/MyD88-, IRF5/IRF7-, and IFNAR-dependent pathway. J Virol 2011; 85:10814-25. [PMID: 21835795 DOI: 10.1128/jvi.00104-11] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Poxviruses are large DNA viruses that replicate in the cytoplasm of infected cells. Myxoma virus is a rabbit poxvirus that belongs to the Leporipoxvirus genus. It causes a lethal disease called myxomatosis in European rabbits but cannot sustain any detectable infection in nonlagomorphs. Vaccinia virus is a prototypal orthopoxvirus that was used as a vaccine to eradicate smallpox. Myxoma virus is nonpathogenic in mice, whereas systemic infection with vaccinia virus can be lethal even in immunocompetent mice. Plasmacytoid dendritic cells (pDCs) are potent type I interferon (IFN)-producing cells that play important roles in antiviral innate immunity. How poxviruses are sensed by pDCs to induce type I IFN production is not well understood. Here we report that infection of primary murine pDCs with myxoma virus, but not with vaccinia virus, induces IFN-α, IFN-β, tumor necrosis factor (TNF), and interleukin-12p70 (IL-12p70) production. Using pDCs derived from genetic knockout mice, we show that the myxoma virus-induced innate immune response requires the endosomal DNA sensor TLR9 and its adaptor MyD88, transcription factors IRF5 and IRF7, and the type I IFN positive-feedback loop mediated by IFNAR1. It is independent of the cytoplasmic RNA sensing pathway mediated by the mitochondrial adaptor molecule MAVS, the TLR3 adaptor TRIF, or the transcription factor IRF3. Using pharmacological inhibitors, we demonstrate that myxoma virus-induced type I IFN and IL-12p70 production in murine pDCs is also dependent on phosphatidylinositol 3-kinase (PI3K) and Akt. Furthermore, our results reveal that the N-terminal Z-DNA/RNA binding domain of vaccinia virulence factor E3, which is missing in the orthologous M029 protein expressed by myxoma virus, plays an inhibitory role in poxvirus sensing and innate cytokine production by murine pDCs.
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222
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Absent in Melanoma 2 (AIM2) is an important mediator of interferon-dependent and -independent HLA-DRA and HLA-DRB gene expression in colorectal cancers. Oncogene 2011; 31:1242-53. [PMID: 21804607 PMCID: PMC3307062 DOI: 10.1038/onc.2011.320] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Absent in Melanoma 2 (AIM2) is a member of the HIN-200 family of hematopoietic, IFN-inducible, nuclear proteins, associated with both, infection defense and tumor pathology. Recently, AIM2 was found to act as a DNA sensor in innate immunity. In addition, we and others have previously demonstrated a high frequency of AIM2-alterations in microsatellite unstable (MSI-H) tumors. To further elucidate AIM2 function in colorectal tumors, we here addressed AIM2-responsive target genes by microarray based gene expression profiling of 22 244 human genes. A total of 111 transcripts were significantly upregulated, whereas 80 transcripts turned out to be significantly downregulated in HCT116 cells, constitutively expressing AIM2, compared with AIM2-negative cells. Among the upregulated genes that were validated by quantitative PCR and western blotting we recognized several interferon-stimulated genes (ISGs: IFIT1, IFIT2, IFIT3, IFI6, IRF7, ISG15, HLA-DRA, HLA-DRB, TLR3 and CIITA), as well as genes involved in intercellular adhesion and matrix remodeling. Expression of ISGs correlated with expression of AIM2 in 10 different IFN-γ treated colorectal cancer cell lines. Moreover, small interfering RNA-mediated knock-down of AIM2 resulted in reduced expression of HLA-DRA, HLA-DRB and CIITA in IFN-γ-treated cells. IFN-γ independent induction of HLA-DR genes and their encoded proteins was also demonstrated upon doxycyclin-regulated transient induction of AIM2. Luciferase reporter assays revealed induction of the HLA-DR promoter upon AIM2 transfection in different cell lines. STAT-signaling was not involved in IFN-γ independent induction of ISGs, arguing against participation of cytokines released in an autostimulating manner. Our data indicate that AIM2 mediates both IFN-γ dependent and independent induction of several ISGs, including genes encoding the major histocompatibility complex (MHC) class II antigens HLA-DR-α and -β. This suggests a novel role of the IFN/AIM2/ISG cascade likewise in cancer cells.
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223
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Abstract
The RIG-I-like receptors (RLRs) RIG-I, MDA5, and LGP2 play a major role in pathogen sensing of RNA virus infection to initiate and modulate antiviral immunity. The RLRs detect viral RNA ligands or processed self RNA in the cytoplasm to trigger innate immunity and inflammation and to impart gene expression that serves to control infection. Importantly, RLRs cooperate in signaling crosstalk networks with Toll-like receptors and other factors to impart innate immunity and to modulate the adaptive immune response. RLR regulation occurs at a variety of levels ranging from autoregulation to ligand and cofactor interactions and posttranslational modifications. Abberant RLR signaling or dysregulation of RLR expression is now implicated in the development of autoimmune diseases. Understanding the processes of RLR signaling and response will provide insights to guide RLR-targeted therapeutics for antiviral and immune-modifying applications.
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Affiliation(s)
- Yueh-Ming Loo
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195-7650, USA
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224
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Interferon regulatory transcription factor 3 protects mice from uterine horn pathology during Chlamydia muridarum genital infection. Infect Immun 2011; 79:3922-33. [PMID: 21788382 DOI: 10.1128/iai.00140-11] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mice with the type I interferon (IFN) receptor gene knocked out (IFNAR KO mice) or deficient for alpha/beta IFN (IFN-α/β) signaling clear chlamydial infection earlier than control mice and develop less oviduct pathology. Initiation of host IFN-β transcription during an in vitro chlamydial infection requires interferon regulatory transcription factor 3 (IRF3). The goal of the present study was to characterize the influence of IRF3 on chlamydial genital infection and its relationship to IFN-β expression in the mouse model. IRF3 KO mice were able to resolve infection as well as control mice, overcoming increased chlamydial colonization and tissue burden early during infection. As previously observed for IFNAR KO mice, IRF3 KO mice generated a potent antigen-specific T cell response. However, in contrast to IFNAR KO mice, IRF3 KO mice exhibited unusually severe dilatation and pathology in the uterine horns but normal oviduct pathology after infection. Although IFN-β expression in vivo was dependent on the presence of IRF3 early in infection (before day 4), the IFN-independent function of IRF3 was likely driving this phenotype. Specifically, early during infection, the number of apoptotic cells and the number of inflammatory cells were significantly less in uterine horns from IRF3 KO mice than in those from control mice, despite an increased chlamydial burden. To delineate the effects of IFN-β versus IRF3, neutralizing IFN-β antibody was administered to wild-type (WT) mice during chlamydial infection. IFN-β depletion in WT mice mimicked that in IFNΑR KO mice but not that in IRF3 KO mice with respect to both chlamydial clearance and reduced oviduct pathology. These data suggest that IRF3 has a role in protection from uterine horn pathology that is independent of its function in IFN-β expression.
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225
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Evasion and subversion of interferon-mediated antiviral immunity by Kaposi's sarcoma-associated herpesvirus: an overview. J Virol 2011; 85:10934-44. [PMID: 21775463 DOI: 10.1128/jvi.00687-11] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Viral invasion of a host cell triggers immune responses with both innate and adaptive components. The innate immune response involving the induction of type I interferons (alpha and beta interferons [IFN-α and -β]) constitutes the first line of antiviral defenses. The type I IFNs signal the transcription of a group of antiviral effector proteins, the IFN-stimulated genes (ISGs), which target distinct viral components and distinct stages of the viral life cycle, aiming to eliminate invading viruses. In the case of Kaposi's sarcoma-associated herpesvirus (KSHV), the etiological agent of Kaposi's sarcoma (KS), a sudden upsurge of type I IFN-mediated innate antiviral signals is seen immediately following both primary de novo infection and viral lytic reactivation from latency. Potent subversion of these responses thus becomes mandatory for the successful establishment of a primary infection following viral entry as well as for efficient viral assembly and egress. This review gives a concise overview of the induction of the type I IFN signaling pathways in response to viral infection and provides a comprehensive understanding of the antagonizing effects exerted by KSHV on type I IFN pathways wielded at various stages of the viral life cycle. Information garnered from this review should result in a better understanding of KSHV biology essential for the development of immunotherapeutic strategies targeted toward KSHV-associated malignancies.
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226
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Lazear HM, Pinto AK, Vogt MR, Gale M, Diamond MS. Beta interferon controls West Nile virus infection and pathogenesis in mice. J Virol 2011; 85:7186-94. [PMID: 21543483 PMCID: PMC3126609 DOI: 10.1128/jvi.00396-11] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 04/27/2011] [Indexed: 12/21/2022] Open
Abstract
Studies with mice lacking the common plasma membrane receptor for type I interferon (IFN-αβR(-)(/)(-)) have revealed that IFN signaling restricts tropism, dissemination, and lethality after infection with West Nile virus (WNV) or several other pathogenic viruses. However, the specific functions of individual IFN subtypes remain uncertain. Here, using IFN-β(-)(/)(-) mice, we defined the antiviral and immunomodulatory function of this IFN subtype in restricting viral infection. IFN-β(-)(/)(-) mice were more vulnerable to WNV infection than wild-type mice, succumbing more quickly and with greater overall mortality, although the phenotype was less severe than that of IFN-αβR(-)(/)(-) mice. The increased susceptibility of IFN-β(-)(/)(-) mice was accompanied by enhanced viral replication in different tissues. Consistent with a direct role for IFN-β in control of WNV replication, viral titers in ex vivo cultures of macrophages, dendritic cells, fibroblasts, and cerebellar granule cell neurons, but not cortical neurons, from IFN-β(-)(/)(-) mice were greater than in wild-type cells. Although detailed immunological analysis revealed no major deficits in the quality or quantity of WNV-specific antibodies or CD8(+) T cells, we observed an altered CD4(+) CD25(+) FoxP3(+) regulatory T cell response, with greater numbers after infection. Collectively, these results suggest that IFN-β controls WNV pathogenesis by restricting infection in key cell types and by modulating T cell regulatory networks.
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Affiliation(s)
| | | | | | - Michael Gale
- Department of Immunology, University of Washington School of Medicine, Seattle, Washington 98195-7650
| | - Michael S. Diamond
- Departments of Medicine
- Pathology & Immunology
- Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110
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227
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Beta interferon-mediated activation of signal transducer and activator of transcription protein 1 interferes with Rickettsia conorii replication in human endothelial cells. Infect Immun 2011; 79:3733-43. [PMID: 21690236 DOI: 10.1128/iai.05008-11] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Infection of the endothelial cell lining of blood vessels with Rickettsia conorii, the causative agent of Mediterranean spotted fever, results in endothelial activation. We investigated the effects of R. conorii infection on the status of the Janus kinase (JAK)-signal transducer and activator of transcription protein (STAT) signaling pathway in human microvascular endothelial cells (HMECs), the most relevant host cell type, in light of rickettsial tropism for microvascular endothelium in vivo. R. conorii infection induced phosphorylation of STAT1 on tyrosine 701 and serine 727 at 24, 48, and 72 h postinfection in HMECs. Employing transcription profile analysis and neutralizing antibodies, we further determined that beta interferon (IFN-β) production and secretion are critical for STAT1 activation. Secreted IFN-β further amplified its own expression via a positive-feedback mechanism, while expression of transcription factors interferon regulatory factor 7 (IRF7) and IRF9, implicated in the IFN-β-STAT1 feedback loop, was also induced. Metabolic activity of rickettsiae was essential for the IFN-β-mediated response(s) because tetracycline treatment inhibited R. conorii replication, IFN-β expression, and STAT1 phosphorylation. Inclusion of IFN-β-neutralizing antibody during infection resulted in significantly enhanced R. conorii replication, whereas addition of exogenous IFN-β had the opposite inhibitory effect. Finally, small interfering RNA-mediated knockdown further confirmed a protective role for STAT1 against intracellular R. conorii replication. In concert, these findings implicate an important role for IFN-β-mediated STAT1 activation in innate immune responses of vascular endothelium to R. conorii infection.
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228
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Abstract
Interferon regulatory factor 7 (IRF7) was originally identified in the context of Epstein-Barr virus (EBV) infection, and has since emerged as the crucial regulator of type I interferons (IFNs) against pathogenic infections, which activate IRF7 by triggering signaling cascades from pathogen recognition receptors (PRRs) that recognize pathogenic nucleic acids. Moreover, IRF7 is a multifunctional transcription factor, underscored by the fact that it is associated with EBV latency, in which IRF7 is induced as well as activated by the EBV principal oncoprotein latent membrane protein-1 (LMP1). Aberrant production of type I IFNs is associated with many types of diseases such as cancers and autoimmune disorders. Thus, tight regulation of IRF7 expression and activity is imperative in dictating appropriate type I IFN production for normal IFN-mediated physiological functions. Posttranslational modifications have important roles in regulation of IRF7 activity, exemplified by phosphorylation, which is indicative of its activation. Furthermore, mounting evidence has shed light on the importance of regulatory ubiquitination in activation of IRF7. Albeit these exciting findings have been made in the past decade since its discovery, many questions related to IRF7 remain to be addressed.
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229
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Petrasek J, Dolganiuc A, Csak T, Kurt-Jones EA, Szabo G. Type I interferons protect from Toll-like receptor 9-associated liver injury and regulate IL-1 receptor antagonist in mice. Gastroenterology 2011; 140:697-708.e4. [PMID: 20727895 PMCID: PMC3031737 DOI: 10.1053/j.gastro.2010.08.020] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 07/27/2010] [Accepted: 08/12/2010] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS Liver inflammation and injury are mediated by the innate immune response, which is regulated by Toll-like receptors (TLR). Activation of TLR9 induces type I interferons (IFNs) via the interferon regulatory factor (IRF)-7. We investigated the roles of type I IFNs in TLR9-associated liver injury. METHODS Wild-type (WT), IRF7-deficient, and IFN-α/β receptor 1 (IFNAR1)-deficient mice were stimulated with TLR9 or TLR2 ligands. Findings from mice were verified in cultured hepatocytes and liver mononuclear cells (LMNCs) as well as in vivo experiments using recombinant type I IFN and interleukin-1 receptor antagonist (IL-1ra). RESULTS Type I IFNs were up-regulated during TLR9-associated liver injury in WT mice. IRF7- and IFNAR1-deficient mice, which have disruptions in type I IFN production or signaling, respectively, had increased liver damage and inflammation, decreased recruitment of dendritic cells, and increased production of tumor necrosis factor α by LMNCs. These findings indicate that type I IFNs have anti-inflammatory activities in liver. IL-1ra, which is produced by LMNCs and hepatocytes, is an IFN-regulated antagonist of the proinflammatory cytokine IL-1β; IRF7- and IFNAR1-deficient mice had decreased levels of IL-1ra compared with WT mice. IL-1ra protected cultured hepatocytes from IL-1β-mediated sensitization to cytotoxicity from tumor necrosis factor α. In vivo exposure to type I IFN, which induced IL-1ra, or administration of IL-1ra reduced TLR9-associated liver injury; the protective effect of type I IFNs therefore appears to be mediated by IFN-dependent induction of IL-1ra. CONCLUSIONS Type I IFNs have anti-inflammatory effects mediated by endogenous IL-1ra, which regulates the extent of TLR9-induced liver damage. Type I IFN signaling is therefore required for protection from immune-mediated liver injury.
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230
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Activation of IFN-β expression by a viral mRNA through RNase L and MDA5. Proc Natl Acad Sci U S A 2011; 108:2118-23. [PMID: 21245317 DOI: 10.1073/pnas.1012409108] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
IFNs play a critical role in innate immunity against viral infections. Melanoma differentiation-associated protein 5 (MDA5), an RNA helicase, is a key component in activating the expression of type I IFNs in response to certain types of viral infection. MDA5 senses noncellular RNA and triggers the signaling cascade that leads to IFN production. Synthetic double-stranded RNAs are known activators of MDA5. Natural single-stranded RNAs have not been reported to activate MDA5, however. We have serendipitously identified a viral mRNA from parainfluenza virus 5 (PIV5) that activates IFN expression through MDA5. We provide evidence that the signaling pathway includes the antiviral enzyme RNase L. The L mRNA of PIV5 activated expression of IFN-β. We have mapped the RNA to a region of 430 nucleotides within the L mRNA of PIV5. Our results indicate that a viral mRNA, with 5'-cap and 3'-poly (A), can activate IFN expression through an RNase L-MDA5 pathway.
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231
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Diversity of interferon antagonist activities mediated by NSP1 proteins of different rotavirus strains. J Virol 2010; 85:1970-9. [PMID: 21177809 DOI: 10.1128/jvi.01801-10] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Studies involving limited numbers of rotavirus (RV) strains have shown that the viral gene 5 product, NSP1, can antagonize beta interferon (IFN-β) expression by inducing the degradation of IFN-regulatory factors (IRFs) (IRF3, IRF5, and IRF7) or a component of the E3 ubiquitin ligase complex responsible for activating NF-κB (β-transducin repeat-containing protein [β-TrCP]). To gain a broader perspective of NSP1 activities, we examined various RV strains for the ability to inhibit IFN-β expression in human cells. We found that all strains encoding wild-type NSP1 impeded IFN-β expression but not always through IRF3 degradation. To identify other degradation targets involved in suppressing IFN-β expression, we used transient expression vectors to test the abilities of a diverse collection of NSP1 proteins to target IRF3, IRF5, IRF7, and β-TrCP for degradation. The results indicated that human RVs rely predominantly on the NSP1-induced degradation of IRF5 and IRF7 to suppress IFN signaling, whereas NSP1 proteins of animal RVs tended to target IRF3, IRF5, and IRF7, allowing the animal viruses a broader attack on the IFN-β signaling pathway. The results also suggested that the NSP1-induced degradation of β-TrCP is an uncommon mechanism of subverting IFN-β signaling but is one that can be shared with NSP1 proteins that induce IRF degradation. Our analysis reveals that the activities of NSP1 proteins are diverse, with no obvious correlations between degradations of pairs of target proteins. Thus, RVs have evolved functionally distinct approaches for subverting the host antiviral response, a property consistent with the immense sequence variation noted for NSP1 proteins.
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232
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Liang Q, Deng H, Sun CW, Townes TM, Zhu F. Negative regulation of IRF7 activation by activating transcription factor 4 suggests a cross-regulation between the IFN responses and the cellular integrated stress responses. THE JOURNAL OF IMMUNOLOGY 2010; 186:1001-10. [PMID: 21148039 DOI: 10.4049/jimmunol.1002240] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cells react to viral infection by exhibiting IFN-based innate immune responses and integrated stress responses, but little is known about the interrelationships between the two. In this study, we report a linkage between these two host-protective cellular mechanisms. We found that IFN regulatory factor (IRF)7, the master regulator of type I IFN gene expression, interacts with activating transcription factor (ATF)4, a key component of the integrated stress responses whose translation is induced by viral infection and various stresses. We have demonstrated that IRF7 upregulates ATF4 activity and expression, whereas ATF4 in return inhibits IRF7 activation, suggesting a cross-regulation between the IFN response and the cellular integrated stress response that controls host innate immune defense against viral infection.
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Affiliation(s)
- Qiming Liang
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
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233
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Xiang Z, Dong C, Qi L, Chen W, Huang L, Li Z, Xia Q, Liu D, Huang M, Weng S, He J. Characteristics of the interferon regulatory factor pairs zfIRF5/7 and their stimulation expression by ISKNV Infection in zebrafish (Danio rerio). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2010; 34:1263-1273. [PMID: 20637800 DOI: 10.1016/j.dci.2010.07.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 07/07/2010] [Accepted: 07/08/2010] [Indexed: 05/29/2023]
Abstract
The interferon regulatory factor (IRF) family plays critical roles in a host's virus infection responses. In this study, two IRF family members, zfIRF5 and zfIRF7, are identified in zebrafish. The zfIRF5 protein encodes 297 amino acids without the carboxyl IRF3 domain. We suggest that zfIRF5 is a new kind of splicing variant, following the nine other kinds of IRF5 splicing variants found in mammals. The zfIRF7 protein is identified as a member of the IRF7 family, compared to the human IRF7 protein, the amino acid sequence of zfIRF7 only with 29% identity and devoid a virus activated domain (VAD). There zfIRF5/7 proteins are expressed in all 11 selective zebrafish tissues within 6-120h of embryonic development. Laser confocal microscopy shows that the full length the proteins are separately located in the cytoplasm. Mutation experiments show that the nuclear localization signals (NLS) of zfIRF7 and zfIRF-5 are at the N-terminal and C-terminals, respectively. In the assays, zfIRF7 expression increases during infectious spleen and kidney necrosis virus (ISKNV) infection and by poly(I:C) and LPS injections, both of which activate the transcriptional activity of L8G5-luc plasmids. The over-expression of zfIRF5/7 activates the interferon-stimulated response elements (ISRE) signal pathway. In addition, zfIRF7 can activate IFN-β, zfIRF5/7. Co-immunoprecipitation assays and laser co-confocal microscopy show that the two proteins could interact, and zfIRF7 may stimulate zfIRF5 to move into the nucleus. The co-expression of zfIRF5/IRF7 suppresses the transcriptional activities of IFN-β in HEK293T cells.
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Affiliation(s)
- Zhiming Xiang
- State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China
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234
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Borrow P, Martínez-Sobrido L, de la Torre JC. Inhibition of the type I interferon antiviral response during arenavirus infection. Viruses 2010; 2:2443-80. [PMID: 21994626 PMCID: PMC3185579 DOI: 10.3390/v2112443] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 10/22/2010] [Accepted: 10/22/2010] [Indexed: 12/20/2022] Open
Abstract
Arenaviruses merit interest both as tractable experimental model systems to study acute and persistent viral infections, and as clinically-important human pathogens. Several arenaviruses cause hemorrhagic fever (HF) disease in humans. In addition, evidence indicates that the globally-distributed prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) is a human pathogen of clinical significance in congenital infections, and also poses a great danger to immunosuppressed individuals. Arenavirus persistence and pathogenesis are facilitated by their ability to overcome the host innate immune response. Mammalian hosts have developed both membrane toll-like receptors (TLR) and cytoplasmic pattern recognition receptors (PRRs) that recognize specific pathogen-associated molecular patterns (PAMPs), resulting in activation of the transcription factors IRF3 or IRF7, or both, which together with NF-κB and ATF-2/c-JUN induce production of type I interferon (IFN-I). IFN-I plays a key role in host anti-microbial defense by mediating direct antiviral effects via up-regulation of IFN-I stimulated genes (ISGs), activating dendritic cells (DCs) and natural killer (NK) cells, and promoting the induction of adaptive responses. Accordingly, viruses have developed a plethora of strategies to disrupt the IFN-I mediated antiviral defenses of the host, and the viral gene products responsible for these disruptions are often major virulence determinants. IRF3- and IRF7-dependent induction of host innate immune responses is frequently targeted by viruses. Thus, the arenavirus nucleoprotein (NP) was shown to inhibit the IFN-I response by interfering with the activation of IRF3. This NP anti-IFN activity, together with alterations in the number and function of DCs observed in mice chronically infected with LCMV, likely play an important role in LCMV persistence in its murine host. In this review we will discuss current knowledge about the cellular and molecular mechanisms by which arenaviruses can subvert the host innate immune response and their implications for understanding HF arenaviral disease as well as arenavirus persistence in their natural hosts.
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Affiliation(s)
- Persephone Borrow
- Nuffield Department of Clinical Medicine, The Jenner Institute, University of Oxford, Compton, Newbury, Berkshire RG20 7NN, UK; E-Mail:
| | - Luis Martínez-Sobrido
- Department of Microbiology and Immunology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Juan Carlos de la Torre
- Department of Immunology and Microbial Science, IMM-6, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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235
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Sathish N, Zhu FX, Golub EE, Liang Q, Yuan Y. Mechanisms of autoinhibition of IRF-7 and a probable model for inactivation of IRF-7 by Kaposi's sarcoma-associated herpesvirus protein ORF45. J Biol Chem 2010; 286:746-56. [PMID: 20980251 DOI: 10.1074/jbc.m110.150920] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
IRF-7 is the master regulator of type I interferon-dependent immune responses controlling both innate and adaptive immunity. Given the significance of IRF-7 in the induction of immune responses, many viruses have developed strategies to inhibit its activity to evade or antagonize host antiviral responses. We previously demonstrated that ORF45, a KSHV immediate-early protein as well as a tegument protein of virions, interacts with IRF-7 and inhibits virus-mediated type I interferon induction by blocking IRF-7 phosphorylation and nuclear translocation (Zhu, F. X., King, S. M., Smith, E. J., Levy, D. E., and Yuan, Y. (2002) Proc. Natl. Acad. Sci. U.S.A. 99, 5573-5578). In this report, we sought to reveal the mechanism underlying the ORF45-mediated inactivation of IRF-7. We found that ORF45 interacts with the inhibitory domain of IRF-7. The most striking feature in the IRF-7 inhibitory domain is two α-helices H3 and H4 that contain many hydrophobic residues and two β-sheets located between the helices that are also very hydrophobic. These hydrophobic subdomains mediate intramolecular interactions that keep the molecule in a closed (inactive) form. Mutagenesis studies confirm the contribution of the hydrophobic helices and sheets to the autoinhibition of IRF-7 in the absence of viral signal. The binding of ORF45 to the critical domain of IRF-7 leads to a hypothesis that ORF45 may maintain the IRF-7 molecule in the closed form and prevent it from being activated in response to viral infection.
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Affiliation(s)
- Narayanan Sathish
- Department of Microbiology, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania 19104, USA
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236
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Schmid S, Mordstein M, Kochs G, García-Sastre A, Tenoever BR. Transcription factor redundancy ensures induction of the antiviral state. J Biol Chem 2010; 285:42013-22. [PMID: 20943654 DOI: 10.1074/jbc.m110.165936] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The transcriptional response to virus infection is thought to be predominantly induced by interferon (IFN) signaling. Here we demonstrate that, in the absence of IFN signaling, an IFN-like transcriptome is still maintained. This transcriptional activity is mediated from IFN-stimulated response elements (ISREs) that bind to both the IFN-stimulated gene factor 3 (ISGF3) as well as to IFN response factor 7 (IRF7). Through a combination of both in vitro biochemistry and in vivo transcriptional profiling, we have dissected what constitutes IRF-specific, ISGF3-specific, or universal ISREs. Taken together, the data presented here suggest that IRF7 can induce an IFN-like transcriptome in the absence of type-I or -III signaling and therefore provides a level of redundancy to cells to ensure the induction of the antiviral state.
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Affiliation(s)
- Sonja Schmid
- Department of Microbiology, Mount Sinai School of Medicine, New York, New York 10029, USA
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237
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Schmeisser H, Mejido J, Balinsky CA, Morrow AN, Clark CR, Zhao T, Zoon KC. Identification of alpha interferon-induced genes associated with antiviral activity in Daudi cells and characterization of IFIT3 as a novel antiviral gene. J Virol 2010; 84:10671-80. [PMID: 20686046 PMCID: PMC2950578 DOI: 10.1128/jvi.00818-10] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 07/22/2010] [Indexed: 01/01/2023] Open
Abstract
A novel assay was developed for Daudi cells in which the antiviral (AV) and antiproliferative (AP) activities of interferon (IFN) can be measured simultaneously. Using this novel assay, conditions allowing IFN AV protection but no growth inhibition were identified and selected. Daudi cells were treated under these conditions, and gene expression microarray analyses were performed. The results of the analysis identified 25 genes associated with IFN-α AV activity. Upregulation of 23 IFN-induced genes was confirmed by using reverse transcription-PCR. Of 25 gene products, 17 were detected by Western blotting at 24 h. Of the 25 genes, 10 have not been previously linked to AV activity of IFN-α. The most upregulated gene was IFIT3 (for IFN-induced protein with tetratricopeptide repeats 3). The results from antibody neutralizing experiments suggested an association of the identified genes with IFN-α AV activity. This association was strengthened by results from IFIT3-small interfering RNA transfection experiments showing decreased expression of IFIT3 and a reduction in the AV activity induced by IFN-α. Overexpression of IFIT3 resulted in a decrease of virus titer. Transcription of AV genes after the treatment of cells with higher concentrations of IFN having an AP effect on Daudi cells suggested pleiotropic functions of identified gene products.
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Affiliation(s)
- H. Schmeisser
- National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892
| | - J. Mejido
- National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892
| | - C. A. Balinsky
- National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892
| | - A. N. Morrow
- National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892
| | - C. R. Clark
- National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892
| | - T. Zhao
- National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892
| | - K. C. Zoon
- National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892
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238
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Higgs R, Lazzari E, Wynne C, Ní Gabhann J, Espinosa A, Wahren-Herlenius M, Jefferies CA. Self protection from anti-viral responses--Ro52 promotes degradation of the transcription factor IRF7 downstream of the viral Toll-Like receptors. PLoS One 2010; 5:e11776. [PMID: 20668674 PMCID: PMC2909902 DOI: 10.1371/journal.pone.0011776] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 07/01/2010] [Indexed: 12/23/2022] Open
Abstract
Ro52 is a member of the TRIM family of single-protein E3 ligases and is also a target for autoantibody production in systemic lupus erythematosus and Sjögren's syndrome. We previously demonstrated a novel function of Ro52 in the ubiquitination and proteasomal degradation of IRF3 following TLR3/4 stimulation. We now present evidence that Ro52 has a similar role in regulating the stability and activity of IRF7. Endogenous immunoprecipitation of Ro52-bound proteins revealed that IRF7 associates with Ro52, an effect which increases following TLR7 and TLR9 stimulation, suggesting that Ro52 interacts with IRF7 post-pathogen recognition. Furthermore, we show that Ro52 ubiquitinates IRF7 in a dose-dependent manner, resulting in a decrease in total IRF7 expression and a subsequent decrease in IFN-α production. IRF7 stability was increased in bone marrow-derived macrophages from Ro52-deficient mice stimulated with imiquimod or CpG-B, consistent with a role for Ro52 in the negative regulation of IRF7 signalling. Taken together, these results suggest that Ro52-mediated ubiquitination promotes the degradation of IRF7 following TLR7 and TLR9 stimulation. As Ro52 is known to be IFN-inducible, this system constitutes a negative-feedback loop that acts to protect the host from the prolonged activation of the immune response.
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Affiliation(s)
- Rowan Higgs
- Molecular and Cellular Therapeutics and RSCI Research Institute, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Elisa Lazzari
- Molecular and Cellular Therapeutics and RSCI Research Institute, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Claire Wynne
- Molecular and Cellular Therapeutics and RSCI Research Institute, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Joan Ní Gabhann
- Molecular and Cellular Therapeutics and RSCI Research Institute, Royal College of Surgeons in Ireland, Dublin, Ireland
| | | | | | - Caroline A. Jefferies
- Molecular and Cellular Therapeutics and RSCI Research Institute, Royal College of Surgeons in Ireland, Dublin, Ireland
- * E-mail:
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239
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Marshall HD, Prince AL, Berg LJ, Welsh RM. IFN-alpha beta and self-MHC divert CD8 T cells into a distinct differentiation pathway characterized by rapid acquisition of effector functions. THE JOURNAL OF IMMUNOLOGY 2010; 185:1419-28. [PMID: 20592282 DOI: 10.4049/jimmunol.1001140] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Nonvirus-specific bystander CD8 T cells bathe in an inflammatory environment during viral infections. To determine whether bystander CD8 T cells are affected by these environments, we examined P14, HY, and OT-I TCR transgenic CD8 T cells sensitized in vivo by IFN-alphabeta-inducing viral infections or by polyinosinic:polycytidylic acid. These sensitized cells rapidly exerted effector functions, such as IFN-gamma production and degranulation, on contact with their high-affinity cognate Ag. Sensitization required self-MHC I and indirect effects of IFN-alphabeta, which together upregulated the T-box transcription factor Eomesodermin, potentially enabling the T cells to rapidly transcribe CTL effector genes and behave like memory cells rather than naive T cells. IL-12, IL-15, IL-18, and IFN-gamma were not individually required for sensitization to produce IFN-gamma, but IL-15 was required for upregulation of granzyme B. These experiments indicate that naive CD8 T cells receive signals from self-MHC and IFN-alphabeta and that, by this process, CD8 T cell responses to viral infection can undergo distinct differentiation pathways, depending on the timing of Ag encounter during the virus-induced IFN response.
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Affiliation(s)
- Heather D Marshall
- Department of Pathology, Program in Immunology and Virology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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240
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Hiscott J, Lin R. Inhibition of the interferon antiviral response by hepatitis C virus. Expert Rev Clin Immunol 2010; 2:49-58. [PMID: 20477087 DOI: 10.1586/1744666x.2.1.49] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hepatitis C virus (HCV) causes acute and chronic hepatitis by targeting the liver hepatocyte for infection and destruction. The standard treatment for chronic HCV infection is pegylated interferon plus ribavirin. Unfortunately, the sustained response rate and associated toxicity with this treatment are far from ideal; more effective and less toxic treatment regimens are needed. With more than 170 million people infected worldwide, there is an unmet medical need for new effective treatments. Recent advances in the understanding of the signaling pathways leading to the host antiviral response to HCV, the mechanisms used by HCV to evade the immune response, the development of cell culture models of HCV infection and the development of small molecule inhibitors of HCV have generated optimism that novel therapeutic approaches to control HCV will soon be available.
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Affiliation(s)
- John Hiscott
- McGill University, Lady Davis Institute for Medical Research - Jewish General Hospital, Department of Microbiology & Immunology, McGill University, Montreal, H3T 1E2, Canada.
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241
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Giordano G, van den Brûle S, Lo Re S, Triqueneaux P, Uwambayinema F, Yakoub Y, Couillin I, Ryffel B, Michiels T, Renauld JC, Lison D, Huaux F. Type I interferon signaling contributes to chronic inflammation in a murine model of silicosis. Toxicol Sci 2010; 116:682-92. [PMID: 20513754 DOI: 10.1093/toxsci/kfq158] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Lung disorders induced by inhaled inorganic particles such as crystalline silica are characterized by chronic inflammation and pulmonary fibrosis. Here, we demonstrate the importance of type I interferon (IFN) in the development of crystalline silica-induced lung inflammation in mice, revealing that viruses and inorganic particles share similar signaling pathways. We found that instillation of silica is followed by the upregulation of IFN-beta and IRF-7 and that granulocytes (GR1(+)) and macrophages/dendritic cells (CD11c(+)) are major producers of type I IFN in response to silica. Two months after silica administration, both IFNAR- and IRF-7-deficient mice produced significantly less pulmonary inflammation and chemokines (KC and CCL2) than competent mice but developed similar lung fibrosis. Our data indicate that type I IFN contributes to the chronic lung inflammation that accompanies silica exposure in mice. Type I IFN is, however, dispensable in the development of silica-induced acute lung inflammation and pulmonary fibrosis.
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Affiliation(s)
- Giulia Giordano
- Louvain Centre for Toxicology and Applied Pharmacology, Université catholique de Louvain, 1200 Brussels, Belgium
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242
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Zou X, Xiang X, Chen Y, Peng T, Luo X, Pan Z. Understanding inhibition of viral proteins on type I IFN signaling pathways with modeling and optimization. J Theor Biol 2010; 265:691-703. [PMID: 20553733 DOI: 10.1016/j.jtbi.2010.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 05/04/2010] [Accepted: 05/04/2010] [Indexed: 12/25/2022]
Abstract
The interferon system provides a powerful and universal intracellular defense mechanism against viruses. As one part of their survival strategies, many viruses have evolved mechanisms to counteract the host type I interferon (IFN-alpha/beta) responses. In this study, we attempt to investigate virus- and double-strand RNA (dsRNA)-triggered type I IFN signaling pathways and understand the inhibition of IFN-alpha/beta induction by viral proteins using mathematical modeling and quantitative analysis. Based on available literature and our experimental data, we develop a mathematical model of virus- and dsRNA-triggered signaling pathways leading to type I IFN gene expression during the primary response, and use the genetic algorithm to optimize all rate constants in the model. The consistency between numerical simulation results and biological experimental data demonstrates that our model is reasonable. Further, we use the model to predict the following phenomena: (1) the dose-dependent inhibition by classical swine fever virus (CSFV) N(pro) or E(rns) protein is observed at a low dose and can reach a saturation above a certain dose, not an increase; (2) E(rns) and N(pro) have no synergic inhibitory effects on IFN-beta induction; (3) the different characters in an important transcription factor, phosphorylated IRF3 (IRF3p), are exhibited because N(pro) or E(rns) counteracted dsRNA- and virus-triggered IFN-beta induction by targeting the different molecules in the signaling pathways and (4) N(pro) inhibits the IFN-beta expression not only by interacting with IFR3 but also by affecting its complex with MITA. Our approaches help to gain insight into system properties and rational therapy design, as well as to generate hypotheses for further research.
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Affiliation(s)
- Xiufen Zou
- School of Mathematics and Statistics, Wuhan University, Wuhan, China
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243
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Peltier DC, Simms A, Farmer JR, Miller DJ. Human neuronal cells possess functional cytoplasmic and TLR-mediated innate immune pathways influenced by phosphatidylinositol-3 kinase signaling. THE JOURNAL OF IMMUNOLOGY 2010; 184:7010-21. [PMID: 20483728 DOI: 10.4049/jimmunol.0904133] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Innate immune pathways are early defense responses important for the immediate control and eventual clearance of many pathogens, where signaling is initiated via pattern recognition receptor (PRR)-mediated events that occur in a ligand- and cell-type specific manner. Within CNS neurons, innate immune pathways are likely crucial to control pathogens that target these essential yet virtually irreplaceable cells. However, relatively little is known about the induction and regulation of neuronal PRR signaling. In this report, we used human neuronal cell lines and primary rat neuronal cultures to examine PRR expression and function. We found that several innate immune receptor ligands, including Sendai virus, the dsRNA mimetic polyinosinic-polycytidylic acid, and LPS all activated differentiation-dependent neuronal innate immune pathways. Functional genetic analyses revealed that IFN regulatory factor 3-mediated pathways that resulted in IFN-beta transcriptional upregulation were activated in cultured human neuronal cells by the PRRs TLR3, MDA5, or RIG-I in a ligand-specific manner. Furthermore, genome-wide transcriptional array and targeted genetic and pharmacologic analyses identified PI3K signaling as crucial for the induction of innate immune pathways in neurons. These results indicate that human neuronal cells possess specific and functional PRR pathways essential for the effective induction of innate immune responses, and suggest that neurons can play an active role in defense against neurotropic pathogens.
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Affiliation(s)
- Daniel C Peltier
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Zhu FX, Sathish N, Yuan Y. Antagonism of host antiviral responses by Kaposi's sarcoma-associated herpesvirus tegument protein ORF45. PLoS One 2010; 5:e10573. [PMID: 20485504 PMCID: PMC2868026 DOI: 10.1371/journal.pone.0010573] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 04/15/2010] [Indexed: 12/19/2022] Open
Abstract
Virus infection of a cell generally evokes an immune response by the host to defeat the intruder in its effort. Many viruses have developed an array of strategies to evade or antagonize host antiviral responses. Kaposi's sarcoma-associated herpesvirus (KSHV) is demonstrated in this report to be able to prevent activation of host antiviral defense mechanisms upon infection. Cells infected with wild-type KSHV were permissive for superinfection with vesicular stomatitis virus (VSV), suggesting that KSHV virions fail to induce host antiviral responses. We previously showed that ORF45, a KSHV immediate-early protein as well as a tegument protein of virions, interacts with IRF-7 and inhibits virus-mediated type I interferon induction by blocking IRF-7 phosphorylation and nuclear translocation (Zhu et al., Proc. Natl. Acad. Sci. USA. 99:5573-5578, 2002). Here, using an ORF45-null recombinant virus, we demonstrate a profound role of ORF45 in inhibiting host antiviral responses. Infection of cells with an ORF45-null mutant recombinant KSHV (BAC-stop45) triggered an immune response that resisted VSV super-infection, concomitantly associated with appreciable increases in transcription of type I IFN and downstream anti-viral effector genes. Gain-of-function analysis showed that ectopic expression of ORF45 in human fibroblast cells by a lentivirus vector decreased the antiviral responses of the cells. shRNA-mediated silencing of IRF-7, that predominantly regulates both the early and late phase induction of type I IFNs, clearly indicated its critical contribution to the innate antiviral responses generated against incoming KSHV particles. Thus ORF45 through its targeting of the crucial IRF-7 regulated type I IFN antiviral responses significantly contributes to the KSHV survival immediately following a primary infection allowing for progression onto subsequent stages in its life-cycle.
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Affiliation(s)
- Fan Xiu Zhu
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America
| | - Narayanan Sathish
- Department of Microbiology, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Yan Yuan
- Department of Microbiology, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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245
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Qiao L, Phipps-Yonas H, Hartmann B, Moran TM, Sealfon SC, Hayot F. Immune response modeling of interferon beta-pretreated influenza virus-infected human dendritic cells. Biophys J 2010; 98:505-14. [PMID: 20159146 DOI: 10.1016/j.bpj.2009.10.049] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2009] [Revised: 09/18/2009] [Accepted: 10/30/2009] [Indexed: 12/20/2022] Open
Abstract
The pretreatment of human dendritic cells with interferon-beta enhances their immune response to influenza virus infection. We measured the expression levels of several key players in that response over a period of 13 h both during pretreatment and after viral infection. Their activation profiles reflect the presence of both negative and positive feedback loops in interferon induction and interferon signaling pathway. Based on these measurements, we have developed a comprehensive computational model of cellular immune response that elucidates its mechanism and its dynamics in interferon-pretreated dendritic cells, and provides insights into the effects of duration and strength of pretreatment.
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Affiliation(s)
- Liang Qiao
- Department of Neurology, Mount Sinai School of Medicine, New York, New York, USA
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246
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Loewendorf A, Benedict CA. Modulation of host innate and adaptive immune defenses by cytomegalovirus: timing is everything. J Intern Med 2010; 267:483-501. [PMID: 20433576 PMCID: PMC2902254 DOI: 10.1111/j.1365-2796.2010.02220.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Human cytomegalovirus (HCMV) (HHV-5, a beta-herpesvirus) causes the vast majority of infection-related congenital birth defects, and can trigger severe disease in immune suppressed individuals. The high prevalence of societal infection, the establishment of lifelong persistence and the growing number of immune-related diseases where HCMV is touted as a potential promoter is slowly heightening public awareness to this virus. The millions of years of co-evolution between CMV and the immune system of its host provides for a unique opportunity to study immune defense strategies, and pathogen counterstrategies. Dissecting the timing of the cellular and molecular processes that regulate innate and adaptive immunity to this persistent virus has revealed a complex defense network that is shaped by CMV immune modulation, resulting in a finely tuned host-pathogen relationship.
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Affiliation(s)
- A Loewendorf
- Division of Molecular Immunology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
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247
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Divergent susceptibilities of human herpesvirus 6 variants to type I interferons. Proc Natl Acad Sci U S A 2010; 107:8369-74. [PMID: 20404187 DOI: 10.1073/pnas.0909951107] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Two distinct human herpesvirus 6 (HHV-6) variants infect humans. HHV-6B is the etiologic agent of roseola and is associated with life-threatening neurological diseases, such as encephalitis, as well as organ transplant failure. The epidemiology and disease association for HHV-6A remain ill-defined. Specific anti-HHV-6 drugs do not exist and classic antiherpes drugs have secondary effects that are often problematic for transplant patients. Clinical trials using IFN were also performed with inconclusive results. We investigated the efficacy of type I IFN (alpha/beta) in controlling HHV-6 infection. We report that cells infected with laboratory strains and primary isolates of HHV-6B are resistant to IFN-alpha/beta antiviral actions as a result of improper IFN-stimulated gene (ISGs) expression. In contrast, HHV-6A-infected cells were responsive to IFN-alpha/beta with pronounced antiviral effects observed. Type II IFN (gamma)-signaling was unaltered in cells infected by either variant. The HHV-6B immediate-early 1 (IE1) physically interacts with STAT2 and sequestrates it to the nucleus. As a consequence, IE1B prevents the binding of ISGF3 to IFN-responsive gene promoters, resulting in ISG silencing. In comparison, HHV-6A and its associated IE1 protein displayed marginal ISG inhibitory activity relative to HHV-6B. The ISG inhibitory domain of IE1B mapped to a 41 amino acid region absent from IE1A. Transfer of this IE1B region resulted in a gain of function that conferred ISG inhibitory activity to IE1A. Our work is unique in demonstrating type I IFN signaling defects in HHV-6B-infected cells and highlights a major biological difference between HHV-6 variants.
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248
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Abstract
Recent studies suggest a mechanistic role for molecules induced by type 1 interferons in the pathogenesis of some forms of myositis. For dermatomyositis, evidence that these molecules injure myofibers seems especially strong. In the group of disorders known as polymyositis, the study of blood samples suggests a potential role. It is unknown what drives the sustained presence of type 1 interferon-inducible molecules in these diseases, as the type 1 interferons themselves have not been specifically detected along with their downstream biomarkers. Therapeutic development for blockade of IFNα is in progress aided by the identification of blood genomic biomarkers.
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Affiliation(s)
- Steven A Greenberg
- Department of Neurology, Division of Neuromuscular Disease, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA.
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249
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Lee HR, Kim MH, Lee JS, Liang C, Jung JU. Viral interferon regulatory factors. J Interferon Cytokine Res 2010; 29:621-7. [PMID: 19715458 DOI: 10.1089/jir.2009.0067] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Upon viral infection, the major defensive strategy employed by the host immune system is the activation of the interferon (IFN)-mediated antiviral pathway, which is overseen by IFN regulatory factors (IRFs). In order to complete their life cycles, viruses must find a way to modulate the host IFN-mediated immune response. Kaposi's sarcoma-associated herpesvirus (KSHV), a human tumor-inducing herpesvirus, has developed a unique mechanism for antagonizing cellular IFN-mediated antiviral activity by incorporating viral homolog of the cellular IRFs, called vIRFs, into its genome. Here, we summarize the novel evasion mechanisms by which KSHV, through its vIRFs, circumvents IFN-mediated innate immune responses and deregulates the cell growth control mechanism.
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Affiliation(s)
- Hye-Ra Lee
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA.
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250
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Hall JC, Rosen A. Type I interferons: crucial participants in disease amplification in autoimmunity. Nat Rev Rheumatol 2010; 6:40-9. [PMID: 20046205 DOI: 10.1038/nrrheum.2009.237] [Citation(s) in RCA: 190] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A significant body of data implicates the type I interferon (IFN) pathway in the pathogenesis of autoimmune rheumatic diseases. In these disorders, a self-reinforcing cycle of IFN production can contribute to immunopathology through multiple mechanisms. Type I IFN cytokines are pleiotropic in their effects, mediating antiviral and antitumor activities, and possess numerous immunomodulatory functions for both the innate and adaptive immune responses. A key principle of the type I IFN system is rapid induction and amplification of the signaling pathway, which generates a feed-forward loop of IFN production, ensuring that a vigorous antiviral immune response is mounted. Although such feed-forward pathways are highly adaptive when it comes to rapid and effective virus eradication, this amplification can be maladaptive in immune responses directed against host tissues. Such feed-forward loops, however, create special opportunities for therapy.
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Affiliation(s)
- John C Hall
- Division of Rheumatology, Department of Medicine, Johns Hopkins University School of Medicine, 5200 Eastern Avenue, Mason F. Lord Building, Center Tower, Suite 4100, Room 412, Baltimore, MD 21224, USA
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