651
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Innate immune recognition of DNA: A recent history. Virology 2015; 479-480:146-52. [PMID: 25816762 DOI: 10.1016/j.virol.2015.03.013] [Citation(s) in RCA: 174] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/14/2015] [Accepted: 03/03/2015] [Indexed: 12/15/2022]
Abstract
Innate immune DNA sensing underpins many physiological and pathological responses to DNA, including anti-viral immunity to DNA viruses. Although it has been appreciated for many years that cytosolic DNA can evoke a type I interferon response, it is only within the past decade that the cellular mechanisms responsible for such a response have been defined. Here we review the discoveries that led to an appreciation of the existence of cytosolic DNA sensor proteins, and discuss two key such sensors, cGAS and IFI16, in detail. DNA sensors operate via STING, a protein shown to have a central role in controlling altered gene induction in response to DNA in vivo, and as such to be central to a rapidly expanding list of both protective and harmful responses to DNA. We also discuss recent insights into how and when DNA stimulates innate immunity, and highlight current outstanding questions in the DNA sensing field.
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652
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cGAS-mediated stabilization of IFI16 promotes innate signaling during herpes simplex virus infection. Proc Natl Acad Sci U S A 2015; 112:E1773-81. [PMID: 25831530 DOI: 10.1073/pnas.1424637112] [Citation(s) in RCA: 194] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Interferon γ-inducible protein 16 (IFI16) and cGMP-AMP synthase (cGAS) have both been proposed to detect herpesviral DNA directly in herpes simplex virus (HSV)-infected cells and initiate interferon regulatory factor-3 signaling, but it has been unclear how two DNA sensors could both be required for this response. We therefore investigated their relative roles in human foreskin fibroblasts (HFFs) infected with HSV or transfected with plasmid DNA. siRNA depletion studies showed that both are required for the production of IFN in infected HFFs. We found that cGAS shows low production of cGMP-AMP in infected cells, but instead cGAS is partially nuclear in normal human fibroblasts and keratinocytes, interacts with IFI16 in fibroblasts, and promotes the stability of IFI16. IFI16 is associated with viral DNA and targets to viral genome complexes, consistent with it interacting directly with viral DNA. Our results demonstrate that IFI16 and cGAS cooperate in a novel way to sense nuclear herpesviral DNA and initiate innate signaling.
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653
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Single amino acid change in STING leads to constitutive active signaling. PLoS One 2015; 10:e0120090. [PMID: 25790474 PMCID: PMC4366210 DOI: 10.1371/journal.pone.0120090] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 01/20/2015] [Indexed: 12/04/2022] Open
Abstract
The production of cytokines by the immune system in response to cytosolic DNA plays an important role in host defense, autoimmune disease, and cancer immunogenicity. Recently a cytosolic DNA signaling pathway that is dependent on the endoplasmic reticulum adaptor and cyclic dinucleotide sensor protein STING has been identified. Association of cytosolic DNA with cyclic-GMP-AMP synthase (cGAS) activates its enzymatic activity to synthesize the cyclic dinucleotide second messenger cGAMP from GTP and ATP. Direct detection of cGAMP by STING triggers the activation of IRF3 and NF-kB, and the production of type I interferons and proinflammatory cytokines. The mechanism of how STING is able to mediate downstream signaling remains incompletely understood although it has been shown that dimerization is a prerequisite. Here, we identify a single amino acid change in STING that confers constitutive active signaling. This mutation appears to both enhance ability of STING to both dimerize and associate with its downstream target TBK1.
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654
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Brinkmann MM, Dağ F, Hengel H, Messerle M, Kalinke U, Čičin-Šain L. Cytomegalovirus immune evasion of myeloid lineage cells. Med Microbiol Immunol 2015; 204:367-82. [PMID: 25776081 DOI: 10.1007/s00430-015-0403-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 02/28/2015] [Indexed: 12/23/2022]
Abstract
Cytomegalovirus (CMV) evades the immune system in many different ways, allowing the virus to grow and its progeny to spread in the face of an adverse environment. Mounting evidence about the antiviral role of myeloid immune cells has prompted the research of CMV immune evasion mechanisms targeting these cells. Several cells of the myeloid lineage, such as monocytes, dendritic cells and macrophages, play a role in viral control, but are also permissive for CMV and are naturally infected by it. Therefore, CMV evasion of myeloid cells involves mechanisms that qualitatively differ from the evasion of non-CMV-permissive immune cells of the lymphoid lineage. The evasion of myeloid cells includes effects in cis, where the virus modulates the immune signaling pathways within the infected myeloid cell, and those in trans, where the virus affects somatic cells targeted by cytokines released from myeloid cells. This review presents an overview of CMV strategies to modulate and evade the antiviral activity of myeloid cells in cis and in trans.
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Affiliation(s)
- Melanie M Brinkmann
- Viral Immune Modulation Research Group, Helmholtz Centre for Infection Research, Inhoffenstraße 7, 38124, Brunswick, Germany
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655
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IFI44 suppresses HIV-1 LTR promoter activity and facilitates its latency. Virology 2015; 481:142-50. [PMID: 25776761 DOI: 10.1016/j.virol.2015.02.046] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 12/08/2014] [Accepted: 02/07/2015] [Indexed: 01/23/2023]
Abstract
IFI44 is an interferon-alfa inducible protein, and is associated with infection of several viruses. However, IFI44 elicits minimal antiviral effects on these viruses, and its exact role is still unknown. Here we show that IFI44 inhibits HIV-1 replication in vitro. Through depletion of endogenous IFI44 or overexpression of IFI44 we confirm that IFI44 suppresses HIV-1 LTR promoter activity and affects viral transcription. Furthermore, we find that IFI44 localizes to nuclei and binds to the HIV-1 LTR promoter in HIV-1 infected cells. Removing suppression of HIV-1 transcription benefits reactivation of HIV-1 proviruses for purging latent reservoirs. We demonstrate that depletion of endogenous IFI44 in J-LAT cells induces reactivation of latent HIV-1. Based on these results, we propose a model in which IFI44 is recruited to the HIV-1 LTR, which may suppress viral transcription and prevent reactivation of latent HIV-1. Our study suggests a previously unrecognized anti-HIV phenomenon for interferon-stimulated proteins.
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656
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Wang J, Chu B, Du L, Han Y, Zhang X, Fan S, Wang Y, Yang G. Molecular cloning and functional characterization of porcine cyclic GMP-AMP synthase. Mol Immunol 2015; 65:436-45. [PMID: 25765883 DOI: 10.1016/j.molimm.2015.02.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 02/01/2015] [Accepted: 02/05/2015] [Indexed: 12/31/2022]
Abstract
Cyclic GMP-AMP synthase (cGAS), which belongs to the nucleotidyltransferase family, recognizes cytosolic DNA and induces the type I interferon (IFN) pathway through the synthesis of the second messenger cGAMP. In this study, porcine cGAS (p-cGAS) was identified and its tissue distribution, subcellular localization, and functions in innate immunity were characterized. The coding sequence of p-cGAS is 1494 bp long, encodes 497 amino acids, and is most similar (74%) to Bos taurus cGAS. p-cGAS mRNA is abundant in the spleen, duodenum, jejunum, and ileum. The subcellular distribution of p-cGAS is not only in the cytosol, but also on the endoplasmic reticulum (ER) membrane. The overexpression of wild-type p-cGAS in porcine kidney epithelial cells, but not its catalytically inactive mutants, induced IFN-β expression, which was dependent on STING and IRF3. However, the downregulation of p-cGAS by RNA interference markedly reduced IFN-β expression after pseudorabies virus (PRV) infection or poly(dA:dT) transfection. These results demonstrate that p-cGAS is an important DNA sensor, required for IFN-β activation.
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Affiliation(s)
- Jiang Wang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China; Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Beibei Chu
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China; Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China.
| | - Lili Du
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China; Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Yingqian Han
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China; Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Xuemei Zhang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China; Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Shuangshuang Fan
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China; Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Yueying Wang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China; Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Guoyu Yang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China; Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China.
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657
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Kell AM, Gale M. RIG-I in RNA virus recognition. Virology 2015; 479-480:110-21. [PMID: 25749629 PMCID: PMC4424084 DOI: 10.1016/j.virol.2015.02.017] [Citation(s) in RCA: 299] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 01/16/2015] [Accepted: 02/10/2015] [Indexed: 02/07/2023]
Abstract
Antiviral immunity is initiated upon host recognition of viral products via non-self molecular patterns known as pathogen-associated molecular patterns (PAMPs). Such recognition initiates signaling cascades that induce intracellular innate immune defenses and an inflammatory response that facilitates development of the acquired immune response. The retinoic acid-inducible gene I (RIG-I) and the RIG-I-like receptor (RLR) protein family are key cytoplasmic pathogen recognition receptors that are implicated in the recognition of viruses across genera and virus families, including functioning as major sensors of RNA viruses, and promoting recognition of some DNA viruses. RIG-I, the charter member of the RLR family, is activated upon binding to PAMP RNA. Activated RIG-I signals by interacting with the adapter protein MAVS leading to a signaling cascade that activates the transcription factors IRF3 and NF-κB. These actions induce the expression of antiviral gene products and the production of type I and III interferons that lead to an antiviral state in the infected cell and surrounding tissue. RIG-I signaling is essential for the control of infection by many RNA viruses. Recently, RIG-I crosstalk with other pathogen recognition receptors and components of the inflammasome has been described. In this review, we discuss the current knowledge regarding the role of RIG-I in recognition of a variety of virus families and its role in programming the adaptive immune response through cross-talk with parallel arms of the innate immune system, including how RIG-I can be leveraged for antiviral therapy. RIG-I is a cytosolic pathogen recognition receptor. RIG-I binds to PAMP RNA. RIG-I initiates the immune response to RNA virus infection.
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Affiliation(s)
- Alison M Kell
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington School of Medicine, Seattle, WA, USA
| | - Michael Gale
- Center for Innate Immunity and Immune Disease, Department of Immunology, University of Washington School of Medicine, Seattle, WA, USA.
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658
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Knipe DM. Nuclear sensing of viral DNA, epigenetic regulation of herpes simplex virus infection, and innate immunity. Virology 2015; 479-480:153-9. [PMID: 25742715 DOI: 10.1016/j.virol.2015.02.009] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/04/2015] [Accepted: 02/05/2015] [Indexed: 12/31/2022]
Abstract
Herpes simplex virus (HSV) undergoes a lytic infection in epithelial cells and a latent infection in neuronal cells, and epigenetic mechanisms play a major role in the differential gene expression under the two conditions. HSV viron DNA is not associated with histones but is rapidly loaded with heterochromatin upon entry into the cell. Viral proteins promote reversal of the epigenetic silencing in epithelial cells while the viral latency-associated transcript promotes additional heterochromatin in neuronal cells. The cellular sensors that initiate the chromatinization of foreign DNA have not been fully defined. IFI16 and cGAS are both essential for innate sensing of HSV DNA, and new evidence shows how they work together to initiate innate signaling. IFI16 also plays a role in the heterochromatinization of HSV DNA, and this review will examine how IFI16 integrates epigenetic regulation and innate sensing of foreign viral DNA to show how these two responses are related.
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Affiliation(s)
- David M Knipe
- Harvard Medical School, Department of Microbiology and Immunobiology, 77 Avenue Louis Pasteur, Boston, MA 02115, United States.
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659
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A bacterial cyclic dinucleotide activates the cytosolic surveillance pathway and mediates innate resistance to tuberculosis. Nat Med 2015; 21:401-6. [PMID: 25730264 PMCID: PMC4390473 DOI: 10.1038/nm.3813] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Accepted: 02/03/2015] [Indexed: 12/14/2022]
Abstract
Detection of cyclic-di-adenosine monophosphate (c-di-AMP), a bacterial second messenger, by the host cytoplasmic surveillance pathway (CSP) is known to elicit Type I interferon responses critical for antimicrobial defense1–3. However, the mechanisms and role of c-di-AMP signaling in Mycobacterium tuberculosis virulence remain unclear. Here we show that resistance to tuberculosis (TB) requires CSP-mediated detection of c-di-AMP produced by M. tuberculosis and that levels of c-di-AMP modulate the fate of infection. We found that a di-adenylate cyclase (disA or dacA)4 over-expressing M. tuberculosis strain that secretes excess c-di-AMP activates the interferon regulatory factor (IRF) pathway with enhanced levels of IFN-β, elicits increased macrophage autophagy, and exhibits significant attenuation in mice. We show that c-di-AMP-mediated IFN-β induction during M. tuberculosis infection requires stimulator of interferon genes (STING)5-signaling. We observed that c-di-AMP induction of IFN-β is independent of the cytosolic nucleic acid receptor cyclic-GMP-AMP (cGAMP) synthase (cGAS)6–7, but cGAS nevertheless contributes substantially to the overall IFN-β response to M. tuberculosis infection. In sum, our results reveal c-di-AMP to be a key mycobacterial pathogen associated molecular pattern (PAMP) driving host Type I IFN responses and autophagy. These findings suggest that modulating the levels of this small molecule may lead to novel immunotherapeutic strategies against TB.
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660
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Crow MS, Javitt A, Cristea IM. A proteomics perspective on viral DNA sensors in host defense and viral immune evasion mechanisms. J Mol Biol 2015; 427:1995-2012. [PMID: 25728651 DOI: 10.1016/j.jmb.2015.02.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/11/2015] [Accepted: 02/17/2015] [Indexed: 12/22/2022]
Abstract
The sensing of viral DNA is an essential step of cellular immune response to infections with DNA viruses. These human pathogens are spread worldwide, triggering a wide range of virus-induced diseases, and are associated with high levels of morbidity and mortality. Despite similarities between DNA molecules, mammalian cells have the remarkable ability to distinguish viral DNA from their own DNA. This detection is carried out by specialized antiviral proteins, called DNA sensors. These sensors bind to foreign DNA to activate downstream immune signaling pathways and alert neighboring cells by eliciting the expression of antiviral cytokines. The sensing of viral DNA was shown to occur both in the cytoplasm and in the nucleus of infected cells, disproving the notion that sensing occurred by simple spatial separation of viral and host DNA. A number of omic approaches, in particular, mass-spectrometry-based proteomic methods, have significantly contributed to the constantly evolving field of viral DNA sensing. Here, we review the impact of omic methods on the identification of viral DNA sensors, as well as on the characterization of mechanisms involved in host defense or viral immune evasion.
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Affiliation(s)
- Marni S Crow
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544, USA
| | - Aaron Javitt
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544, USA
| | - Ileana M Cristea
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544, USA.
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661
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Hoffmann HH, Schneider WM, Rice CM. Interferons and viruses: an evolutionary arms race of molecular interactions. Trends Immunol 2015; 36:124-38. [PMID: 25704559 DOI: 10.1016/j.it.2015.01.004] [Citation(s) in RCA: 287] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 01/16/2015] [Accepted: 01/16/2015] [Indexed: 12/24/2022]
Abstract
Over half a century has passed since interferons (IFNs) were discovered and shown to inhibit virus infection in cultured cells. Since then, researchers have steadily brought to light the molecular details of IFN signaling, catalogued their pleiotropic effects on cells, and harnessed their therapeutic potential for a variety of maladies. While advances have been plentiful, several fundamental questions have yet to be answered and much complexity remains to be unraveled. We explore the current knowledge surrounding four main questions: are type I IFN subtypes differentially produced in response to distinct pathogens? How are IFN subtypes distinguished by cells? What are the mechanisms and consequences of viral antagonism? Lastly, how can the IFN response be harnessed to improve vaccine efficacy?
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Affiliation(s)
- Hans-Heinrich Hoffmann
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - William M Schneider
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA.
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662
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Storek KM, Gertsvolf NA, Ohlson MB, Monack DM. cGAS and Ifi204 cooperate to produce type I IFNs in response to Francisella infection. THE JOURNAL OF IMMUNOLOGY 2015; 194:3236-45. [PMID: 25710914 DOI: 10.4049/jimmunol.1402764] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Type I IFN production is an important host immune response against viral and bacterial infections. However, little is known about the ligands and corresponding host receptors that trigger type I IFN production during bacterial infections. We used a model intracellular pathogen, Francisella novicida, to begin characterizing the type I IFN response to bacterial pathogens. F. novicida replicates in the cytosol of host cells and elicits a robust type I IFN response that is largely TLR independent, but is dependent on the adapter molecule STING, suggesting that the type I IFN stimulus during F. novicida infection is cytosolic. In this study, we report that the cytosolic DNA sensors, cyclic GMP-AMP synthase (cGAS) and Ifi204, are both required for the STING-dependent type I IFN response to F. novicida infection in both primary and immortalized murine macrophages. We created cGAS, Ifi204, and Sting functional knockouts in RAW264.7 macrophages and demonstrated that cGAS and Ifi204 cooperate to sense dsDNA and activate the STING-dependent type I IFN pathway. In addition, we show that dsDNA from F. novicida is an important type I IFN stimulating ligand. One outcome of cGAS-STING signaling is the activation of the absent in melanoma 2 inflammasome in response to F. novicida infection. Whereas the absent in melanoma 2 inflammasome is beneficial to the host during F. novicida infection, type I IFN signaling by STING and IFN regulatory factor 3 is detrimental to the host during F. novicida infection. Collectively, our studies indicate that cGAS and Ifi204 cooperate to sense cytosolic dsDNA and F. novicida infection to produce a strong type I IFN response.
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Affiliation(s)
- Kelly M Storek
- Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305; and
| | - Nina A Gertsvolf
- Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305; and
| | | | - Denise M Monack
- Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305; and
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663
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Zhu J, Ghosh A, Sarkar SN. OASL-a new player in controlling antiviral innate immunity. Curr Opin Virol 2015; 12:15-9. [PMID: 25676874 DOI: 10.1016/j.coviro.2015.01.010] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/17/2015] [Accepted: 01/22/2015] [Indexed: 01/17/2023]
Abstract
The cellular innate immune system plays a crucial role in mounting the initial resistance to virus infection. It is comprised of various pattern-recognition receptors that induce type I interferon production, which further shapes the adaptive immunity. However, to overcome this resistance and promote replication, viruses have evolved mechanisms to evade this host innate immune response. Here we discuss a recently described mechanism of boosting the innate immunity by oligoadenylate synthetase-like (OASL) protein, which can potentially be used to overcome viral evasion and enhance innate immunity.
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Affiliation(s)
- Jianzhong Zhu
- Cancer Virology Program, University of Pittsburgh Cancer Institute, United States; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Arundhati Ghosh
- Cancer Virology Program, University of Pittsburgh Cancer Institute, United States; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Saumendra N Sarkar
- Cancer Virology Program, University of Pittsburgh Cancer Institute, United States; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
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664
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Quinn KM, Zak DE, Costa A, Yamamoto A, Kastenmuller K, Hill BJ, Lynn GM, Darrah PA, Lindsay RWB, Wang L, Cheng C, Nicosia A, Folgori A, Colloca S, Cortese R, Gostick E, Price DA, Gall JGD, Roederer M, Aderem A, Seder RA. Antigen expression determines adenoviral vaccine potency independent of IFN and STING signaling. J Clin Invest 2015; 125:1129-46. [PMID: 25642773 DOI: 10.1172/jci78280] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 12/23/2014] [Indexed: 12/13/2022] Open
Abstract
Recombinant adenoviral vectors (rAds) are lead vaccine candidates for protection against a variety of pathogens, including Ebola, HIV, tuberculosis, and malaria, due to their ability to potently induce T cell immunity in humans. However, the ability to induce protective cellular immunity varies among rAds. Here, we assessed the mechanisms that control the potency of CD8 T cell responses in murine models following vaccination with human-, chimpanzee-, and simian-derived rAds encoding SIV-Gag antigen (Ag). After rAd vaccination, we quantified Ag expression and performed expression profiling of innate immune response genes in the draining lymph node. Human-derived rAd5 and chimpanzee-derived chAd3 were the most potent rAds and induced high and persistent Ag expression with low innate gene activation, while less potent rAds induced less Ag expression and robustly induced innate immunity genes that were primarily associated with IFN signaling. Abrogation of type I IFN or stimulator of IFN genes (STING) signaling increased Ag expression and accelerated CD8 T cell response kinetics but did not alter memory responses or protection. These findings reveal that the magnitude of rAd-induced memory CD8 T cell immune responses correlates with Ag expression but is independent of IFN and STING and provide criteria for optimizing protective CD8 T cell immunity with rAd vaccines.
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665
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Cox DJ, Field RH, Williams DG, Baran M, Bowie AG, Cunningham C, Dunne A. DNA sensors are expressed in astrocytes and microglia in vitro and are upregulated during gliosis in neurodegenerative disease. Glia 2015; 63:812-25. [PMID: 25627810 PMCID: PMC4657478 DOI: 10.1002/glia.22786] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 12/18/2014] [Accepted: 12/19/2014] [Indexed: 12/27/2022]
Abstract
The detection of nucleic acids by the innate immune system is an essential host response during viral infection. In recent years, a number of immune sensors capable of recognizing cytosolic DNA have been identified and include the PYHIN family members AIM2, IFI16, and p204 as well as the enzyme, cGAS. Activation of these receptors leads to the induction of antiviral genes including Type‐1 interferons and chemokines such as CCL5. We have carried out extensive expression profiling of these DNA sensors and other members of the PYHIN family in highly purified primary astrocytes and microglia and have demonstrated that both cell types express the majority of these proteins at the mRNA level. In microglia, several family members are highly upregulated in response to IFN‐β treatment while both cell types induce robust proinflammatory and antiviral cytokine production (e.g., IL‐6, CCL5, IFN‐β) in the presence of immune stimulatory DNA and RNA. The production of IL‐6 is partially dependent on the interferon receptor as is IFN‐β itself. Furthermore, we have found that p204 and AIM2 are upregulated in a Type I IFN dependent fashion in vivo, in a murine model of chronic neurodegeneration. Given the propensity of inflammatory responses to cause neuronal damage, increased expression and activation of these receptors, not only during viral infection but also during sterile inflammatory responses, has the potential to exacerbate existing neuroinflammation leading to further damage and impaired neurogenesis. GLIA 2015;63:812–825
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Affiliation(s)
- Donal J Cox
- Molecular Immunology Group, School, of Biochemistry and Immunology and Immunology Research Centre, Trinity College Dublin, Ireland
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666
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Sarkar SN. Could boosting the oligoadenylate synthetase-like pathway bring a new era of antiviral therapy? Future Virol 2015; 9:1011-1014. [PMID: 25620998 DOI: 10.2217/fvl.14.81] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Saumendra N Sarkar
- Cancer Virology Program, University of Pittsburgh Cancer Institute & Department of Microbiology & Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Tel.: +1 412 623 7720
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667
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Ma F, Li B, Liu SY, Iyer SS, Yu Y, Wu A, Cheng G. Positive feedback regulation of type I IFN production by the IFN-inducible DNA sensor cGAS. THE JOURNAL OF IMMUNOLOGY 2015; 194:1545-54. [PMID: 25609843 DOI: 10.4049/jimmunol.1402066] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Rapid and robust induction of type I IFN (IFN-I) is a critical event in host antiviral innate immune response. It has been well demonstrated that cyclic GMP-AMP (cGAMP) synthase (cGAS) plays an important role in sensing cytosolic DNA and triggering STING dependent signaling to induce IFN-I. However, it is largely unknown how cGAS itself is regulated during pathogen infection and IFN-I production. In this study, we show that pattern recognition receptor (PRR) ligands, including lipid A, LPS, poly(I:C), poly(dA:dT), and cGAMP, induce cGAS expression in an IFN-I-dependent manner in both mouse and human macrophages. Further experiments indicated that cGAS is an IFN-stimulated gene (ISG), and two adjacent IFN-sensitive response elements (ISREs) in the promoter region of cGAS mediate the induction of cGAS by IFN-I. Additionally, we show that optimal production of IFN-β triggered by poly (dA:dT) or HSV-1 requires IFNAR signaling. Knockdown of the constitutively expressed DNA sensor DDX41 attenuates poly(dA:dT)-triggered IFN-β production and cGAS induction. By analyzing the dynamic expression of poly(dA:dT)-induced IFN-β and cGAS transcripts, we have found that induction of IFN-β is earlier than cGAS. Furthermore, we have provided evidence that induction of cGAS by IFN-I meditates the subsequent positive feedback regulation of DNA-triggered IFN-I production. Thus, our study not only provides a novel mechanism of modulating cGAS expression, but also adds another layer of regulation in DNA-triggered IFN-I production by induction of cGAS.
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Affiliation(s)
- Feng Ma
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Bing Li
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095; and
| | - Su-yang Liu
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Shankar S Iyer
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Yongxin Yu
- Division of Oral Biology and Medicine, School of Dentistry and Broad Stem Cell Research Center, University of California, Los Angeles, Los Angeles, CA 90095
| | - Aiping Wu
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Genhong Cheng
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095;
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668
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Sun C, Schattgen SA, Pisitkun P, Jorgensen JP, Hilterbrand AT, Wang LJ, West JA, Hansen K, Horan KA, Jakobsen MR, O'Hare P, Adler H, Sun R, Ploegh HL, Damania B, Upton JW, Fitzgerald KA, Paludan SR. Evasion of innate cytosolic DNA sensing by a gammaherpesvirus facilitates establishment of latent infection. THE JOURNAL OF IMMUNOLOGY 2015; 194:1819-31. [PMID: 25595793 DOI: 10.4049/jimmunol.1402495] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Herpesviruses are DNA viruses harboring the capacity to establish lifelong latent-recurrent infections. There is limited knowledge about viruses targeting the innate DNA-sensing pathway, as well as how the innate system impacts on the latent reservoir of herpesvirus infections. In this article, we report that murine gammaherpesvirus 68 (MHV68), in contrast to α- and β-herpesviruses, induces very limited innate immune responses through DNA-stimulated pathways, which correspondingly played only a minor role in the control of MHV68 infections in vivo. Similarly, Kaposi's sarcoma-associated herpesvirus also did not stimulate immune signaling through the DNA-sensing pathways. Interestingly, an MHV68 mutant lacking deubiquitinase (DUB) activity, embedded within the large tegument protein open reading frame (ORF)64, gained the capacity to stimulate the DNA-activated stimulator of IFN genes (STING) pathway. We found that ORF64 targeted a step in the DNA-activated pathways upstream of the bifurcation into the STING and absent in melanoma 2 pathways, and lack of the ORF64 DUB was associated with impaired delivery of viral DNA to the nucleus, which, instead, localized to the cytoplasm. Correspondingly, the ORF64 DUB active site mutant virus exhibited impaired ability to establish latent infection in wild-type, but not STING-deficient, mice. Thus, gammaherpesviruses evade immune activation by the cytosolic DNA-sensing pathway, which, in the MHV68 model, facilitates establishment of infections.
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Affiliation(s)
- Chenglong Sun
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark; Aarhus Research Center for Innate Immunology, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Stefan A Schattgen
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655
| | - Prapaporn Pisitkun
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark; Aarhus Research Center for Innate Immunology, Aarhus University, DK-8000 Aarhus C, Denmark; Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand 10400
| | - Joan P Jorgensen
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark; Aarhus Research Center for Innate Immunology, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Adam T Hilterbrand
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712
| | - Lucas J Wang
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712
| | - John A West
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599
| | - Kathrine Hansen
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark; Aarhus Research Center for Innate Immunology, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Kristy A Horan
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Martin R Jakobsen
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark; Aarhus Research Center for Innate Immunology, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Peter O'Hare
- Section of Virology, Faculty of Medicine, Imperial College, St. Mary's Campus, London W2 1PG, United Kingdom
| | - Heiko Adler
- Helmholtz Zentrum Munich, German Research Center for Environmental Health, D-81377 Munich, Germany
| | - Ren Sun
- Department of Molecular Biology and Medical Pharmacology, Faculty of Medicine, University of California, Los Angeles, Los Angeles, CA 90095; and
| | - Hidde L Ploegh
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
| | - Blossom Damania
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599
| | - Jason W Upton
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712
| | - Katherine A Fitzgerald
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655
| | - Søren R Paludan
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark; Aarhus Research Center for Innate Immunology, Aarhus University, DK-8000 Aarhus C, Denmark;
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669
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Mesenchymal stem cells detect and defend against gammaherpesvirus infection via the cGAS-STING pathway. Sci Rep 2015; 5:7820. [PMID: 25592282 PMCID: PMC4296288 DOI: 10.1038/srep07820] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 11/27/2014] [Indexed: 12/13/2022] Open
Abstract
Mesenchymal stem cells (MSCs) are widely used in clinical settings to treat tissue injuries and autoimmune disorders due to their multipotentiality and immunomodulation. Long-term observations reveal several complications after MSCs infusion, especially herpesviral infection. However, the mechanism of host defense against herpesviruses in MSCs remains largely unknown. Here we showed that murine gammaherpesvirus-68 (MHV-68), which is genetically and biologically related to human gammaherpesviruses, efficiently infected MSCs both in vitro and in vivo. Cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS) was identified as the sensor of MHV-68 in MSCs for the first time. Moreover, the cytosolic DNA sensing pathway mediated a potent anti-herpesviral effect through the adaptor STING and downstream kinase TBK1. Furthermore, blockade of IFN signaling suggested that cytosolic DNA sensing triggered both IFN-dependent and -independent anti-herpesviral responses. Our findings demonstrate that cGAS-STING mediates innate immunity to gammaherpesvirus infection in MSCs, which may provide a clue to develop therapeutic strategy.
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670
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Schliehe C, Flynn EK, Vilagos B, Richson U, Swaminanthan S, Bosnjak B, Bauer L, Kandasamy RK, Griesshammer IM, Kosack L, Schmitz F, Litvak V, Sissons J, Lercher A, Bhattacharya A, Khamina K, Trivett AL, Tessarollo L, Mesteri I, Hladik A, Merkler D, Kubicek S, Knapp S, Epstein MM, Symer DE, Aderem A, Bergthaler A. The methyltransferase Setdb2 mediates virus-induced susceptibility to bacterial superinfection. Nat Immunol 2015; 16:67-74. [PMID: 25419628 PMCID: PMC4320687 DOI: 10.1038/ni.3046] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 11/03/2014] [Indexed: 12/12/2022]
Abstract
Immune responses are tightly regulated to ensure efficient pathogen clearance while avoiding tissue damage. Here we report that Setdb2 was the only protein lysine methyltransferase induced during infection with influenza virus. Setdb2 expression depended on signaling via type I interferons, and Setdb2 repressed expression of the gene encoding the neutrophil attractant CXCL1 and other genes that are targets of the transcription factor NF-κB. This coincided with occupancy by Setdb2 at the Cxcl1 promoter, which in the absence of Setdb2 displayed diminished trimethylation of histone H3 Lys9 (H3K9me3). Mice with a hypomorphic gene-trap construct of Setdb2 exhibited increased infiltration of neutrophils during sterile lung inflammation and were less sensitive to bacterial superinfection after infection with influenza virus. This suggested that a Setdb2-mediated regulatory crosstalk between the type I interferons and NF-κB pathways represents an important mechanism for virus-induced susceptibility to bacterial superinfection.
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Affiliation(s)
- Christopher Schliehe
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Elizabeth K. Flynn
- Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Bojan Vilagos
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Udochuku Richson
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | | | - Berislav Bosnjak
- Department of Dermatology, DIAID, Experimental Allergy, Medical University of Vienna, Vienna, Austria
| | - Lisa Bauer
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Richard K. Kandasamy
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Isabel M. Griesshammer
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Lindsay Kosack
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Frank Schmitz
- Seattle Biomedical Research Institute, Seattle, WA, USA
| | | | - James Sissons
- Seattle Biomedical Research Institute, Seattle, WA, USA
| | - Alexander Lercher
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Anannya Bhattacharya
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Kseniya Khamina
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Anna L. Trivett
- Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Lino Tessarollo
- Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Ildiko Mesteri
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | - Anastasiya Hladik
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Medicine 1, Medical University of Vienna, Vienna, Austria
| | - Doron Merkler
- Department of Pathology and Immunology, Division of Clinical Pathology, University & University Hospital of Geneva, Geneva, Switzerland
- Department of Neuropathology, Georg-August-University Goettingen, Germany
| | - Stefan Kubicek
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Sylvia Knapp
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Medicine 1, Medical University of Vienna, Vienna, Austria
| | - Michelle M. Epstein
- Department of Dermatology, DIAID, Experimental Allergy, Medical University of Vienna, Vienna, Austria
| | - David E. Symer
- Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
- Ohio State University Comprehensive Cancer Center, Columbus, OH, USA
| | - Alan Aderem
- Seattle Biomedical Research Institute, Seattle, WA, USA
| | - Andreas Bergthaler
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
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671
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New insights into innate immune restriction of West Nile virus infection. Curr Opin Virol 2014; 11:1-6. [PMID: 25554924 DOI: 10.1016/j.coviro.2014.12.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 12/04/2014] [Indexed: 12/11/2022]
Abstract
West Nile virus (WNV) is an encephalitic flavivirus that has provided a valuable experimental system for studying viral pathogenesis and immunity. Although in vitro approaches and mouse models of infection have identified pattern recognition receptor and interferon pathways that control WNV infection, our appreciation of specific antiviral effectors has been more limited. In this review, we highlight recent advances in our understanding of the host factors that restrict WNV infection in mammals and insects, especially those resulting from large-scale screening approaches.
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672
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Alcorn JF, Sarkar SN. What is the oligoadenylate synthetases-like protein and does it have therapeutic potential for influenza? Expert Rev Respir Med 2014; 9:1-3. [PMID: 25544107 DOI: 10.1586/17476348.2015.994608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Besides its pandemic potential, seasonal influenza infection is associated with an estimated 250,000 to 500,000 deaths worldwide every year. Part of this virulence of influenza virus can be attributed to its ability to evade the host innate immune response. Here, we discuss the possibility of using a recently described mechanism of boosting the innate immunity by oligoadenylate synthetase-like protein, to combat influenza infections.
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Affiliation(s)
- John F Alcorn
- Department of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA
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673
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Feng H, Zhang YB, Zhang QM, Li Z, Zhang QY, Gui JF. Zebrafish IRF1 Regulates IFN Antiviral Response through Binding to IFNϕ1 and IFNϕ3 Promoters Downstream of MyD88 Signaling. THE JOURNAL OF IMMUNOLOGY 2014; 194:1225-38. [DOI: 10.4049/jimmunol.1402415] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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674
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Lemos H, Huang L, McGaha T, Mellor AL. STING, nanoparticles, autoimmune disease and cancer: a novel paradigm for immunotherapy? Expert Rev Clin Immunol 2014; 11:155-65. [PMID: 25521938 DOI: 10.1586/1744666x.2015.995097] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
DNA has potent immunogenic properties that are useful to enhance vaccine efficacy. DNA also incites hyperinflammation and autoimmunity if DNA sensing is not regulated. Paradoxically, DNA regulates immunity and autoimmunity when administered systemically as DNA nanoparticles. DNA nanoparticles regulated immunity via cytosolic DNA sensors that activate the signaling adaptor stimulator of interferon genes. In this review, we describe how DNA sensing to activate stimulator of interferon genes promotes regulatory responses and discuss the biological and clinical implications of these responses for understanding disease progression and designing better therapies for patients with chronic inflammatory diseases, such as autoimmune syndromes or cancer.
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Affiliation(s)
- Henrique Lemos
- Cancer immunology, Inflammation and Tolerance Program, Cancer Center, Georgia Regents University, 1120 15th St, Augusta GA 30912, USA
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675
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STING agonists induce an innate antiviral immune response against hepatitis B virus. Antimicrob Agents Chemother 2014; 59:1273-81. [PMID: 25512416 DOI: 10.1128/aac.04321-14] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Chronicity of hepatitis B virus (HBV) infection is due to the failure of a host to mount a sufficient immune response to clear the virus. The aim of this study was to identify small-molecular agonists of the pattern recognition receptor (PRR)-mediated innate immune response to control HBV infection. To achieve this goal, a coupled mouse macrophage and hepatocyte culture system mimicking the intrahepatic environment was established and used to screen small-molecular compounds that activate macrophages to produce cytokines, which in turn suppress HBV replication in a hepatocyte-derived stable cell line supporting HBV replication in a tetracycline-inducible manner. An agonist of the mouse stimulator of interferon (IFN) genes (STING), 5,6-dimethylxanthenone-4-acetic acid (DMXAA), was found to induce a robust cytokine response in macrophages that efficiently suppressed HBV replication in mouse hepatocytes by reducing the amount of cytoplasmic viral nucleocapsids. Profiling of cytokines induced by DMXAA and agonists of representative Toll-like receptors (TLRs) in mouse macrophages revealed that, unlike TLR agonists that induced a predominant inflammatory cytokine/chemokine response, the STING agonist induced a cytokine response dominated by type I IFNs. Moreover, as demonstrated in an HBV hydrodynamic mouse model, intraperitoneal administration of DMXAA significantly induced the expression of IFN-stimulated genes and reduced HBV DNA replication intermediates in the livers of mice. This study thus proves the concept that activation of the STING pathway induces an antiviral cytokine response against HBV and that the development of small-molecular human STING agonists as immunotherapeutic agents for treatment of chronic hepatitis B is warranted.
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676
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The nucleoprotein of newly emerged H7N9 influenza A virus harbors a unique motif conferring resistance to antiviral human MxA. J Virol 2014; 89:2241-52. [PMID: 25505067 DOI: 10.1128/jvi.02406-14] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Interferon-induced Mx proteins show strong antiviral activity against influenza A viruses (IAVs). We recently demonstrated that the viral nucleoprotein (NP) determines resistance of seasonal and pandemic human influenza viruses to Mx, while avian isolates retain Mx sensitivity. We identified a surface-exposed cluster of amino acids in NP of pandemic A/BM/1/1918 (H1N1), comprising isoleucine-100, proline-283, and tyrosine-313, that is essential for reduced Mx sensitivity in cell culture and in vivo. This cluster has been maintained in all descendant seasonal strains, including A/PR/8/34 (PR/8). Accordingly, two substitutions in the NP of PR/8 [PR/8(mut)] to the Mx-sensitive amino acids (P283L and Y313F) led to attenuation in Mx1-positive mice. Serial lung passages of PR/8(mut) in Mx1 mice resulted in a single exchange of tyrosine to asparagine at position 52 in NP (in close proximity to the amino acid cluster at positions 100, 283, and 313), which partially compensates loss of Mx resistance in PR/8(mut). Intriguingly, the NP of the newly emerged avian-origin H7N9 virus also contains an asparagine at position 52 and shows reduced Mx sensitivity. N52Y substitution in NP results in increased sensitivity of the H7N9 virus to human Mx, indicating that this residue is a determinant of Mx resistance in mammals. Our data strengthen the hypothesis that the human Mx protein represents a potent barrier against zoonotic transmission of avian influenza viruses. However, the H7N9 viruses overcome this restriction by harboring an NP that is less sensitive to Mx-mediated host defense. This might contribute to zoonotic transmission of H7N9 and to the severe to fatal outcome of H7N9 infections in humans. IMPORTANCE The natural host of influenza A viruses (IAVs) are aquatic birds. Occasionally, these viruses cross the species barrier, as in early 2013 when an avian H7N9 virus infected humans in China. Since then, multiple transmissions of H7N9 viruses to humans have occurred, leaving experts puzzled about molecular causes for such efficient crossing of the species barrier compared to other avian influenza viruses. Mx proteins are known restriction factors preventing influenza virus replication. Unfortunately, some viruses (e.g., human IAV) have developed some resistance, which is associated with specific amino acids in their nucleoproteins, the target of Mx function. Here, we demonstrate that the novel H7N9 bird IAV already carries a nucleoprotein that overcomes the inhibition of viral replication by human MxA. This is the first example of an avian IAV that is naturally less sensitive to Mx-mediated inhibition and might explain why H7N9 viruses transmitted efficiently to humans.
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677
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Shu C, Li X, Li P. The mechanism of double-stranded DNA sensing through the cGAS-STING pathway. Cytokine Growth Factor Rev 2014; 25:641-8. [PMID: 25007740 PMCID: PMC4254336 DOI: 10.1016/j.cytogfr.2014.06.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 06/16/2014] [Indexed: 12/25/2022]
Abstract
Microbial nucleic acids induce potent innate immune responses by stimulating the expression of type I interferons. Cyclic GMP-AMP synthase (cGAS) is a cytosolic dsDNA sensor mediating the innate immunity to microbial DNA. cGAS is activated by dsDNA and catalyze the synthesis of a cyclic dinucleotide cGAMP with 2',5' and 3',5'phosphodiester linkages. cGAMP binds to the adaptor STING located on the endoplasmic reticulum membrane and mediates the recruitment and activation of the protein kinase TBK1 and transcription factor IRF3. Phosphorylated IRF3 translocates to the nucleus and initiates the transcription of the IFN-β gene. The crystal structures of cGAS and its complex with dsDNA, STING and its complex with various cyclic dinucleotides have been determined recently. Here we summarize the results from these structural studies and provide an overview about the mechanism of cGAS activation by dsDNA, the catalytic mechanism of cGAS, and the structural basis of STING activation by cGAMP.
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Affiliation(s)
- Chang Shu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA
| | - Xin Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA
| | - Pingwei Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA.
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678
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Abrogation of the interferon response promotes more efficient human cytomegalovirus replication. J Virol 2014; 89:1479-83. [PMID: 25392213 DOI: 10.1128/jvi.02988-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The effect of abrogating the interferon (IFN) response on human cytomegalovirus (HCMV) replication was investigated using primary human cells engineered to block either the production of or the response to type I IFNs. In IFN-deficient cells, HCMV produced larger plaques and spread and replicated more rapidly than in parental cells. These cells demonstrate the vital role of IFNs in controlling HCMV replication and provide useful tools to investigate the IFN response to HCMV.
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679
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Acchioni C, Marsili G, Perrotti E, Remoli AL, Sgarbanti M, Battistini A. Type I IFN--a blunt spear in fighting HIV-1 infection. Cytokine Growth Factor Rev 2014; 26:143-58. [PMID: 25466629 DOI: 10.1016/j.cytogfr.2014.10.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 10/22/2014] [Indexed: 02/07/2023]
Abstract
For more than 50 years, Type I Interferon (IFN) has been recognized as critical in controlling viral infections. IFN is produced downstream germ-line encoded pattern recognition receptors (PRRs) upon engagement by pathogen-associated molecular patterns (PAMPs). As a result, hundreds of different interferon-stimulated genes (ISGs) are rapidly induced, acting in both autocrine and paracrine manner to build a barrier against viral replication and spread. ISGs encode proteins with direct antiviral and immunomodulatory activities affecting both innate and adaptive immune responses. During infection with viruses, as HIV-1, that can establish a persistent infection, IFN although produced, is not able to block the initial infection and a chronic IFN-mediated immune activation/inflammation becomes a pathogenic mechanism of disease progression. This review will briefly summarize when and how IFN is produced during HIV-1 infection and the way this innate immune response is manipulated by the virus to its own advantage to drive chronic immune activation and progression to AIDS.
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Affiliation(s)
- Chiara Acchioni
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, Rome 00161, Italy
| | - Giulia Marsili
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, Rome 00161, Italy
| | - Edvige Perrotti
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, Rome 00161, Italy
| | - Anna Lisa Remoli
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, Rome 00161, Italy
| | - Marco Sgarbanti
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, Rome 00161, Italy
| | - Angela Battistini
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, 299, Rome 00161, Italy.
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680
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Tomasello E, Pollet E, Vu Manh TP, Uzé G, Dalod M. Harnessing Mechanistic Knowledge on Beneficial Versus Deleterious IFN-I Effects to Design Innovative Immunotherapies Targeting Cytokine Activity to Specific Cell Types. Front Immunol 2014; 5:526. [PMID: 25400632 PMCID: PMC4214202 DOI: 10.3389/fimmu.2014.00526] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 10/07/2014] [Indexed: 12/15/2022] Open
Abstract
Type I interferons (IFN-I) were identified over 50 years ago as cytokines critical for host defense against viral infections. IFN-I promote anti-viral defense through two main mechanisms. First, IFN-I directly reinforce or induce de novo in potentially all cells the expression of effector molecules of intrinsic anti-viral immunity. Second, IFN-I orchestrate innate and adaptive anti-viral immunity. However, IFN-I responses can be deleterious for the host in a number of circumstances, including secondary bacterial or fungal infections, several autoimmune diseases, and, paradoxically, certain chronic viral infections. We will review the proposed nature of protective versus deleterious IFN-I responses in selected diseases. Emphasis will be put on the potentially deleterious functions of IFN-I in human immunodeficiency virus type 1 (HIV-1) infection, and on the respective roles of IFN-I and IFN-III in promoting resolution of hepatitis C virus (HCV) infection. We will then discuss how the balance between beneficial versus deleterious IFN-I responses is modulated by several key parameters including (i) the subtypes and dose of IFN-I produced, (ii) the cell types affected by IFN-I, and (iii) the source and timing of IFN-I production. Finally, we will speculate how integration of this knowledge combined with advanced biochemical manipulation of the activity of the cytokines should allow designing innovative immunotherapeutic treatments in patients. Specifically, we will discuss how induction or blockade of specific IFN-I responses in targeted cell types could promote the beneficial functions of IFN-I and/or dampen their deleterious effects, in a manner adapted to each disease.
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Affiliation(s)
- Elena Tomasello
- UM2, Centre d'Immunologie de Marseille-Luminy (CIML), Aix-Marseille University , Marseille , France ; U1104, Institut National de la Santé et de la Recherche Médicale (INSERM) , Marseille , France ; UMR7280, Centre National de la Recherche Scientifique (CNRS) , Marseille , France
| | - Emeline Pollet
- UM2, Centre d'Immunologie de Marseille-Luminy (CIML), Aix-Marseille University , Marseille , France ; U1104, Institut National de la Santé et de la Recherche Médicale (INSERM) , Marseille , France ; UMR7280, Centre National de la Recherche Scientifique (CNRS) , Marseille , France
| | - Thien-Phong Vu Manh
- UM2, Centre d'Immunologie de Marseille-Luminy (CIML), Aix-Marseille University , Marseille , France ; U1104, Institut National de la Santé et de la Recherche Médicale (INSERM) , Marseille , France ; UMR7280, Centre National de la Recherche Scientifique (CNRS) , Marseille , France
| | - Gilles Uzé
- UMR 5235, Centre National de la Recherche Scientifique (CNRS), University Montpellier II , Montpellier , France
| | - Marc Dalod
- UM2, Centre d'Immunologie de Marseille-Luminy (CIML), Aix-Marseille University , Marseille , France ; U1104, Institut National de la Santé et de la Recherche Médicale (INSERM) , Marseille , France ; UMR7280, Centre National de la Recherche Scientifique (CNRS) , Marseille , France
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681
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Intracellular sensing of viral DNA by the innate immune system. Microbes Infect 2014; 16:1002-12. [PMID: 25316508 DOI: 10.1016/j.micinf.2014.09.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 09/25/2014] [Accepted: 09/26/2014] [Indexed: 12/19/2022]
Abstract
Recent years have seen a great advance in knowledge of how a host senses infection. Nucleic acids, as a common denominator to all pathogens, are at the centre of several of the sensing pathways, especially those involved with the recognition of viruses. In this review we discuss the current knowledge on how intracellular DNA is sensed by the mammalian host.
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682
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Ohkuri T, Ghosh A, Kosaka A, Zhu J, Ikeura M, David M, Watkins SC, Sarkar SN, Okada H. STING contributes to antiglioma immunity via triggering type I IFN signals in the tumor microenvironment. Cancer Immunol Res 2014; 2:1199-208. [PMID: 25300859 DOI: 10.1158/2326-6066.cir-14-0099] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Although type I IFNs play critical roles in antiviral and antitumor activity, it remains to be elucidated how type I IFNs are produced in sterile conditions of the tumor microenvironment and directly affect tumor-infiltrating immune cells. Mouse de novo gliomas show increased expression of type I IFN messages, and in mice, CD11b(+) brain-infiltrating leukocytes (BIL) are the main source of type I IFNs that are induced partially in a STING (stimulator of IFN genes)-dependent manner. Consequently, glioma-bearing Sting(Gt) (/Gt) mice showed shorter survival and lower expression levels of Ifns compared with wild-type mice. Furthermore, BILs of Sting(Gt) (/Gt) mice showed increased CD11b(+) Gr-1(+) immature myeloid suppressor and CD25(+) Foxp3(+) regulatory T cells (Treg) and decreased IFNγ-producing CD8(+) T cells. CD4(+) and CD8(+) T cells that received direct type I IFN signals showed lesser degrees of regulatory activity and increased levels of antitumor activity, respectively. Finally, intratumoral administration of a STING agonist (cyclic diguanylate monophosphate; c-di-GMP) improved the survival of glioma-bearing mice associated with enhanced type I IFN signaling, Cxcl10 and Ccl5, and T-cell migration into the brain. In combination with subcutaneous OVA peptide vaccination, c-di-GMP increased OVA-specific cytotoxicity of BILs and prolonged their survival. These data demonstrate significant contributions of STING to antitumor immunity via enhancement of type I IFN signaling in the tumor microenvironment and suggest a potential use of STING agonists for the development of effective immunotherapy, such as the combination with antigen-specific vaccinations.
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Affiliation(s)
- Takayuki Ohkuri
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. Department of Brain Tumor, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania
| | - Arundhati Ghosh
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. Cancer Virology Programs, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania
| | - Akemi Kosaka
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. Department of Brain Tumor, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania
| | - Jianzhong Zhu
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. Cancer Virology Programs, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania
| | - Maki Ikeura
- Department of Brain Tumor, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania
| | - Michael David
- Division of Biology, University of California San Diego, La Jolla, California
| | - Simon C Watkins
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Saumendra N Sarkar
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. Cancer Virology Programs, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania. Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
| | - Hideho Okada
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. Department of Brain Tumor, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania. Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. Department of Cancer Immunology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania.
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683
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Abe H, Hayes CN, Chayama K. New insight into the enhanced effect of pegylated interferon-α. Hepatology 2014; 60:1435-7. [PMID: 24944103 DOI: 10.1002/hep.27269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/01/2014] [Accepted: 06/13/2014] [Indexed: 12/07/2022]
Affiliation(s)
- Hiromi Abe
- Department of Gastroenterology and Metabolism, Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; Laboratory for Digestive Diseases, Center for Genomic Medicine, RIKEN, Hiroshima, Japan; Liver Research Project Center, Hiroshima University, Hiroshima, Japan
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684
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Lemos H, Huang L, McGaha TL, Mellor AL. Cytosolic DNA sensing via the stimulator of interferon genes adaptor: Yin and Yang of immune responses to DNA. Eur J Immunol 2014; 44:2847-53. [PMID: 25143264 PMCID: PMC4197080 DOI: 10.1002/eji.201344407] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 07/21/2014] [Accepted: 07/29/2014] [Indexed: 12/15/2022]
Abstract
DNA is immunogenic and many cells express cytosolic DNA sensors that activate the stimulator of interferon genes (STING) adaptor to trigger interferon type I (IFN-β) release, a potent immune activator. DNA sensing to induce IFN-β triggers host immunity to pathogens but constitutive DNA sensing can induce sustained IFN-β release that incites autoimmunity. Here, we focus on cytosolic DNA sensing via the STING/IFN-β pathway that regulates immune responses. Recent studies reveal that cytosolic DNA sensing via the STING/IFN-β pathway induces indoleamine 2,3 dioxygenase (IDO), which catabolizes tryptophan to suppress effector and helper T-cell responses and activate Foxp3-lineage CD4(+) regulatory T (Treg) cells. During homeostasis, and in some inflammatory settings, specialized innate immune cells in the spleen and lymph nodes may ingest and sense cytosolic DNA to reinforce tolerance that prevents autoimmunity. However, malignancies and pathogens may exploit DNA-induced regulatory responses to suppress natural and vaccine-induced immunity to malignant and infected cells. In this review, we discuss the biologic significance of regulatory responses to DNA and novel approaches to exploit DNA-induced immune responses for therapeutic benefit. The ability of DNA to drive tolerogenic or immunogenic responses highlights the need to evaluate immune responses to DNA in physiologic settings relevant to disease progression or therapy.
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Affiliation(s)
- Henrique Lemos
- Cancer immunology, Inflammation and Tolerance Program, Cancer Center, Georgia Regents University, Augusta, GA, USA
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685
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Zhou Q, Lin H, Wang S, Wang S, Ran Y, Liu Y, Ye W, Xiong X, Zhong B, Shu HB, Wang YY. The ER-Associated Protein ZDHHC1 Is a Positive Regulator of DNA Virus-Triggered, MITA/STING-Dependent Innate Immune Signaling. Cell Host Microbe 2014; 16:450-61. [DOI: 10.1016/j.chom.2014.09.006] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 08/13/2014] [Accepted: 09/11/2014] [Indexed: 10/24/2022]
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686
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M27 expressed by cytomegalovirus counteracts effective type I interferon induction of myeloid cells but not of plasmacytoid dendritic cells. J Virol 2014; 88:13638-50. [PMID: 25231302 DOI: 10.1128/jvi.00216-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED In healthy individuals, the functional immune system effectively confines human cytomegalovirus (CMV) replication, while viral immune evasion and persistence preclude sterile immunity. Mouse CMV (MCMV) is a well-established model to study the delicate CMV-host balance. Effective control of MCMV infection depends on the induction of protective type I interferon (IFN-I) responses. Nevertheless, it is unclear whether in professional antigen-presenting cell subsets MCMV-encoded evasins inhibit the induction of IFN-I responses. Upon MCMV treatment, enhanced expression of MCMV immediate-early and early proteins was detected in bone marrow cultures of macrophages and myeloid dendritic cells compared with plasmacytoid dendritic cell cultures, whereas plasmacytoid dendritic cells mounted more vigorous IFN-I responses. Experiments with Toll-like receptor (TLR)- and/or RIG-I like helicase (RLH)-deficient cell subsets revealed that upon MCMV treatment of myeloid cells, IFN-I responses were triggered independently of TLR and RLH signaling, whereas in plasmacytoid dendritic cells, IFN-I induction was strictly TLR dependent. Macrophages and myeloid dendritic cells treated with either UV-inactivated MCMV or live MCMV that lacked the STAT2 antagonist M27 mounted significantly higher IFN-I responses than cells treated with live wild-type MCMV. In contrast, plasmacytoid dendritic cells responded similarly to UV-inactivated and live MCMV. These experiments illustrated that M27 not only inhibited IFN-I-mediated receptor signaling, but also evaded the induction of IFN responses in myeloid dendritic cells. Furthermore, we found that additional MCMV-encoded evasins were needed to efficiently shut off IFN-I responses of macrophages, but not of myeloid dendritic cells, thus further elucidating the subtle adjustment of the host-pathogen balance. IMPORTANCE MCMV may induce IFN-I responses in fibroblasts and epithelial cells, as well as in antigen-presenting cell subsets. We focused on the analysis of IFN-I responses of antigen-presenting cell subsets, including plasmacytoid dendritic cells, myeloid dendritic cells, and macrophages, which are all triggered by MCMV to mount IFN-I responses. Interestingly, myeloid dendritic cells and macrophages, but not plasmacytoid dendritic cells, are readily MCMV infected and support viral gene expression. As expected from previous studies, plasmacytoid dendritic cells sense MCMV Toll-like receptor 9 (TLR9) dependently, whereas in myeloid cells, IFN-I induction is entirely TLR and RLH independent. MCMV-encoded M27 does not impair the IFN-I induction of plasmacytoid dendritic cells, while in myeloid dendritic cells, it reduces IFN-I responses. In macrophages, M27 plus other, not yet identified evasins profoundly inhibit the induction of IFN-I responses. Collectively, these results illustrate that MCMV has evolved diverse mechanisms to differentially modulate IFN-I responses in single immune cell subsets.
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687
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Abstract
Orthobunyaviruses, which have small, tripartite, negative-sense RNA genomes and structurally simple virions composed of just four proteins, can have devastating effects on human health and well-being, either by causing disease in humans or by causing disease in livestock and crops. In this Review, I describe the recent genetic and structural advances that have revealed important insights into the composition of orthobunyavirus virions, viral transcription and replication and viral interactions with the host innate immune response. Lastly, I highlight outstanding questions and areas of future research.
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Affiliation(s)
- Richard M Elliott
- MRC-University of Glasgow Centre for Virus Research, 464 Bearsden Road, Glasgow G61 1QH, UK
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688
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Verrier ER, Gack MU, Baumert TF. Cyclic guanosine monophosphate/adenosine monophosphate synthase (cGAS), innate immune responses, and viral hepatitis. Hepatology 2014; 60:1098-100. [PMID: 24753097 DOI: 10.1002/hep.27187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/12/2014] [Accepted: 04/21/2014] [Indexed: 12/24/2022]
Affiliation(s)
- Eloi R Verrier
- Inserm U1110, Strasbourg, France; Université de Strasbourg Strasbourg, France
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689
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Maringer K, Fernandez-Sesma A. Message in a bottle: lessons learned from antagonism of STING signalling during RNA virus infection. Cytokine Growth Factor Rev 2014; 25:669-79. [PMID: 25212897 PMCID: PMC4330990 DOI: 10.1016/j.cytogfr.2014.08.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 08/05/2014] [Indexed: 02/08/2023]
Abstract
STING has emerged in recent years as an important signalling adaptor in the activation of type I interferon responses during infection with DNA viruses and bacteria. An increasing body of evidence suggests that STING also modulates responses to RNA viruses, though the mechanisms remain less clear. In this review, we give a brief overview of the ways in which STING facilitates sensing of RNA viruses. These include modulation of RIG-I-dependent responses through STING's interaction with MAVS, and more speculative mechanisms involving the DNA sensor cGAS and sensing of membrane remodelling events. We then provide an in-depth literature review to summarise the known mechanisms by which RNA viruses of the families Flaviviridae and Coronaviridae evade sensing through STING. Our own work has shown that the NS2B/3 protease complex of the flavivirus dengue virus binds and cleaves STING, and that an inability to degrade murine STING may contribute to host restriction in this virus. We contrast this to the mechanism employed by the distantly related hepacivirus hepatitis C virus, in which STING is bound and inactivated by the NS4B protein. Finally, we discuss STING antagonism in the coronaviruses SARS coronavirus and human coronavirus NL63, which disrupt K63-linked polyubiquitination and dimerisation of STING (both of which are required for STING-mediated activation of IRF-3) via their papain-like proteases. We draw parallels with less-well characterised mechanisms of STING antagonism in related viruses, and place our current knowledge in the context of species tropism restrictions that potentially affect the emergence of new human pathogens.
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Affiliation(s)
- Kevin Maringer
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; School of Cellular and Molecular Medicine, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Ana Fernandez-Sesma
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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690
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Structure-guided reprogramming of human cGAS dinucleotide linkage specificity. Cell 2014; 158:1011-1021. [PMID: 25131990 PMCID: PMC4157622 DOI: 10.1016/j.cell.2014.07.028] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 07/03/2014] [Accepted: 07/21/2014] [Indexed: 11/21/2022]
Abstract
Cyclic dinucleotides (CDNs) play central roles in bacterial pathogenesis and innate immunity. The mammalian enzyme cGAS synthesizes a unique cyclic dinucleotide (cGAMP) containing a 2'-5' phosphodiester linkage essential for optimal immune stimulation, but the molecular basis for linkage specificity is unknown. Here, we show that the Vibrio cholerae pathogenicity factor DncV is a prokaryotic cGAS-like enzyme whose activity provides a mechanistic rationale for the unique ability of cGAS to produce 2'-5' cGAMP. Three high-resolution crystal structures show that DncV and human cGAS generate CDNs in sequential reactions that proceed in opposing directions. We explain 2' and 3' linkage specificity and test this model by reprogramming the human cGAS active site to produce 3'-5' cGAMP, leading to selective stimulation of alternative STING adaptor alleles in cells. These results demonstrate mechanistic homology between bacterial signaling and mammalian innate immunity and explain how active site configuration controls linkage chemistry for pathway-specific signaling.
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691
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Kambara H, Niazi F, Kostadinova L, Moonka DK, Siegel CT, Post AB, Carnero E, Barriocanal M, Fortes P, Anthony DD, Valadkhan S. Negative regulation of the interferon response by an interferon-induced long non-coding RNA. Nucleic Acids Res 2014; 42:10668-80. [PMID: 25122750 PMCID: PMC4176326 DOI: 10.1093/nar/gku713] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Long non-coding RNAs (lncRNAs) play critical roles in diverse cellular processes; however, their involvement in many critical aspects of the immune response including the interferon (IFN) response remains poorly understood. To address this gap, we compared the global gene expression pattern of primary human hepatocytes before and at three time points after treatment with IFN-α. Among ∼200 IFN-induced lncRNAs, one transcript showed ∼100-fold induction. This RNA, which we named lncRNA-CMPK2, was a spliced, polyadenylated nuclear transcript that was induced by IFN in diverse cell types from human and mouse. Similar to protein-coding IFN-stimulated genes (ISGs), its induction was dependent on JAK-STAT signaling. Intriguingly, knockdown of lncRNA-CMPK2 resulted in a marked reduction in HCV replication in IFN-stimulated hepatocytes, suggesting that it could affect the antiviral role of IFN. We could show that lncRNA-CMPK2 knockdown resulted in upregulation of several protein-coding antiviral ISGs. The observed upregulation was caused by an increase in both basal and IFN-stimulated transcription, consistent with loss of transcriptional inhibition in knockdown cells. These results indicate that the IFN response involves a lncRNA-mediated negative regulatory mechanism. lncRNA-CMPK2 was strongly upregulated in a subset of HCV-infected human livers, suggesting a role in modulation of the IFN response in vivo.
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Affiliation(s)
- Hiroto Kambara
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Farshad Niazi
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Lenche Kostadinova
- Divisions of Infectious and Rheumatic Diseases, Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Dilip K Moonka
- Division of Gastroenterology, Henry Ford Health System, Detroit, MI 48202, USA
| | - Christopher T Siegel
- Department of Surgery, University Hospitals Case Medical Center, Cleveland, OH 44106, USA
| | - Anthony B Post
- Department of Gastroenterology, University Hospitals Case Medical Center, Cleveland, OH 44106, USA
| | - Elena Carnero
- Department of Hepatology and Gene Therapy, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Marina Barriocanal
- Department of Hepatology and Gene Therapy, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Puri Fortes
- Department of Hepatology and Gene Therapy, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Donald D Anthony
- Divisions of Infectious and Rheumatic Diseases, Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Saba Valadkhan
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
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692
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Sandler NG, Bosinger SE, Estes JD, Zhu RTR, Tharp GK, Boritz E, Levin D, Wijeyesinghe S, Makamdop KN, del Prete GQ, Hill BJ, Timmer JK, Reiss E, Yarden G, Darko S, Contijoch E, Todd JP, Silvestri G, Nason M, Norgren RB, Keele BF, Rao S, Langer JA, Lifson JD, Schreiber G, Douek DC. Type I interferon responses in rhesus macaques prevent SIV infection and slow disease progression. Nature 2014; 511:601-5. [PMID: 25043006 PMCID: PMC4418221 DOI: 10.1038/nature13554] [Citation(s) in RCA: 358] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 06/04/2014] [Indexed: 12/26/2022]
Abstract
Inflammation in HIV infection is predictive of non-AIDS morbidity and death, higher set point plasma virus load and virus acquisition; thus, therapeutic agents are in development to reduce its causes and consequences. However, inflammation may simultaneously confer both detrimental and beneficial effects. This dichotomy is particularly applicable to type I interferons (IFN-I) which, while contributing to innate control of infection, also provide target cells for the virus during acute infection, impair CD4 T-cell recovery, and are associated with disease progression. Here we manipulated IFN-I signalling in rhesus macaques (Macaca mulatta) during simian immunodeficiency virus (SIV) transmission and acute infection with two complementary in vivo interventions. We show that blockade of the IFN-I receptor caused reduced antiviral gene expression, increased SIV reservoir size and accelerated CD4 T-cell depletion with progression to AIDS despite decreased T-cell activation. In contrast, IFN-α2a administration initially upregulated expression of antiviral genes and prevented systemic infection. However, continued IFN-α2a treatment induced IFN-I desensitization and decreased antiviral gene expression, enabling infection with increased SIV reservoir size and accelerated CD4 T-cell loss. Thus, the timing of IFN-induced innate responses in acute SIV infection profoundly affects overall disease course and outweighs the detrimental consequences of increased immune activation. Yet, the clinical consequences of manipulation of IFN signalling are difficult to predict in vivo and therapeutic interventions in human studies should be approached with caution.
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Affiliation(s)
- Netanya G Sandler
- 1] Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA [2] Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical Branch at Galveston, Galveston, Texas 77555, USA
| | - Steven E Bosinger
- 1] Division of Microbiology and Immunology, Emory Vaccine Center, Yerkes National Primate Research Center, Atlanta, Georgia 30322, USA [2] Non-Human Primate Genomics Core, Yerkes National Primate Research Center, Robert W. Woodruff Health Sciences Center, Emory University, Atlanta, Georgia 30322, USA
| | - Jacob D Estes
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, Maryland 21702, USA
| | - Richard T R Zhu
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Gregory K Tharp
- 1] Division of Microbiology and Immunology, Emory Vaccine Center, Yerkes National Primate Research Center, Atlanta, Georgia 30322, USA [2] Non-Human Primate Genomics Core, Yerkes National Primate Research Center, Robert W. Woodruff Health Sciences Center, Emory University, Atlanta, Georgia 30322, USA
| | - Eli Boritz
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Doron Levin
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sathi Wijeyesinghe
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Krystelle Nganou Makamdop
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Gregory Q del Prete
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, Maryland 21702, USA
| | - Brenna J Hill
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - J Katherina Timmer
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Emma Reiss
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Ganit Yarden
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Samuel Darko
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Eduardo Contijoch
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - John Paul Todd
- Laboratory of Animal Medicine, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Guido Silvestri
- Division of Microbiology and Immunology, Emory Vaccine Center, Yerkes National Primate Research Center, Atlanta, Georgia 30322, USA
| | - Martha Nason
- Biostatistics Research Branch, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Robert B Norgren
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA
| | - Brandon F Keele
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, Maryland 21702, USA
| | - Srinivas Rao
- Laboratory of Animal Medicine, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Jerome A Langer
- Department of Pharmacology, Rutgers - Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
| | - Jeffrey D Lifson
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, Maryland 21702, USA
| | - Gideon Schreiber
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Daniel C Douek
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
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693
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Analysis of stop-gain and frameshift variants in human innate immunity genes. PLoS Comput Biol 2014; 10:e1003757. [PMID: 25058640 PMCID: PMC4110073 DOI: 10.1371/journal.pcbi.1003757] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 06/16/2014] [Indexed: 12/03/2022] Open
Abstract
Loss-of-function variants in innate immunity genes are associated with Mendelian disorders in the form of primary immunodeficiencies. Recent resequencing projects report that stop-gains and frameshifts are collectively prevalent in humans and could be responsible for some of the inter-individual variability in innate immune response. Current computational approaches evaluating loss-of-function in genes carrying these variants rely on gene-level characteristics such as evolutionary conservation and functional redundancy across the genome. However, innate immunity genes represent a particular case because they are more likely to be under positive selection and duplicated. To create a ranking of severity that would be applicable to innate immunity genes we evaluated 17,764 stop-gain and 13,915 frameshift variants from the NHLBI Exome Sequencing Project and 1,000 Genomes Project. Sequence-based features such as loss of functional domains, isoform-specific truncation and nonsense-mediated decay were found to correlate with variant allele frequency and validated with gene expression data. We integrated these features in a Bayesian classification scheme and benchmarked its use in predicting pathogenic variants against Online Mendelian Inheritance in Man (OMIM) disease stop-gains and frameshifts. The classification scheme was applied in the assessment of 335 stop-gains and 236 frameshifts affecting 227 interferon-stimulated genes. The sequence-based score ranks variants in innate immunity genes according to their potential to cause disease, and complements existing gene-based pathogenicity scores. Specifically, the sequence-based score improves measurement of functional gene impairment, discriminates across different variants in a given gene and appears particularly useful for analysis of less conserved genes. There are well-characterized severe immunodeficiencies associated with loss-of-function variants in innate immunity genes. Genome sequencing projects identify rare stop-gain and frameshift variants in innate immunity genes whose phenotype is uncharacterized. Current methods to estimate the severity of rare stop-gains and frameshifts are based on evolutionary conservation of the gene, the likelihood for redundancy in its function or mutational burden. These parameters are not always applicable to innate immunity genes. We evaluated sequence-level characteristics of more than 30'000 stop-gains and frameshifts and prioritized variants according to their predicted functional consequences. Our scoring approach complements existing tools in the prediction of innate immunity OMIM disease variants and associates with functional readouts such as gene expression. In this framework, we show that many individuals do carry highly pathogenic variants in genes participating in antiviral defense. The clinical assessment of these variants is of significant interest.
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694
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OAS proteins and cGAS: unifying concepts in sensing and responding to cytosolic nucleic acids. Nat Rev Immunol 2014; 14:521-8. [PMID: 25033909 PMCID: PMC7097587 DOI: 10.1038/nri3719] [Citation(s) in RCA: 221] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The presence of nucleic acids in the cytosol alerts the cell to viral infection or damaged self. The oligoadenylate synthase (OAS) proteins and cyclic GMP–AMP synthase (cGAS) are enzymes that detect this danger and promote antiviral immunity. Recent structural studies reveal that these enzymes have a common mechanism of action and probably the same evolutionary origin. Recent discoveries in the field of innate immunity have highlighted the existence of a family of nucleic acid-sensing proteins that have similar structural and functional properties. These include the well-known oligoadenylate synthase (OAS) family proteins and the recently identified OAS homologue cyclic GMP–AMP (cGAMP) synthase (cGAS). The OAS proteins and cGAS are template-independent nucleotidyltransferases that, once activated by double-stranded nucleic acids in the cytosol, produce unique classes of 2′–5′-linked second messenger molecules, which — through distinct mechanisms — have crucial antiviral functions. 2′–5′-linked oligoadenylates limit viral propagation through the activation of the enzyme RNase L, which degrades host and viral RNA, and 2′–5′-linked cGAMP activates downstream signalling pathways to induce de novo antiviral gene expression. In this Progress article, we describe the striking functional and structural similarities between OAS proteins and cGAS, and highlight their roles in antiviral immunity.
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695
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Collins SE, Mossman KL. Danger, diversity and priming in innate antiviral immunity. Cytokine Growth Factor Rev 2014; 25:525-31. [PMID: 25081316 DOI: 10.1016/j.cytogfr.2014.07.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 07/03/2014] [Indexed: 12/24/2022]
Abstract
The prototypic response to viral infection involves the recognition of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs), leading to the activation of transcription factors such as IRF3 and NFkB and production of type 1 IFN. While this response can lead to the induction of hundreds of IFN-stimulated genes (ISGs) and recruitment and activation of immune cells, such a comprehensive response is likely inappropriate for routine low level virus exposure. Moreover, viruses have evolved a plethora of immune evasion strategies to subvert antiviral signalling. There is emerging evidence that cells have developed very sensitive methods of detecting not only specific viral PAMPS, but also more general danger or stress signals associated with viral entry and replication. Such stress-induced cellular responses likely serve to prime cells to respond to further PAMP stimulation or allow for a rapid and localized intracellular response independent of IFN production and its potential immune sequelae. This review discusses diversity in innate antiviral players and pathways, the role of "danger" sensing, and how alternative pathways, such as the IFN-independent pathway, may serve to prime cells for further pathogen attack.
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Affiliation(s)
- Susan E Collins
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Center, Institute for Infectious Disease Research, McMaster University, Hamilton, Canada L8S 4K1
| | - Karen L Mossman
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Center, Institute for Infectious Disease Research, McMaster University, Hamilton, Canada L8S 4K1.
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696
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Jakobsen MR, Paludan SR. IFI16: At the interphase between innate DNA sensing and genome regulation. Cytokine Growth Factor Rev 2014; 25:649-55. [PMID: 25027602 DOI: 10.1016/j.cytogfr.2014.06.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 06/16/2014] [Indexed: 12/18/2022]
Abstract
DNA carries the genetic code, and is also a potent stimulator of innate immune responses. IFI16 is a member of the family of PYHIN proteins and is composed of a PYRIN domain involved in homotypic protein-protein interactions and two HIN domains mediating DNA binding. PYHIN proteins have been described to possess functions as innate pattern recognition receptors or transcriptional regulators. Interestingly, it is now emerging that IFI16, which exhibits both nuclear and cytosolic location, possesses both of these functions. In this review we discuss the current literature on IFI16 and propose key questions now facing this field of research. We propose that IFI16 plays a central role in the close interaction between the innate immune system and cellular regulation of the genome.
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Affiliation(s)
- Martin R Jakobsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Aarhus Research Center for Innate Immunology, Aarhus University, Aarhus, Denmark
| | - Søren R Paludan
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Aarhus Research Center for Innate Immunology, Aarhus University, Aarhus, Denmark.
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697
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Cai X, Chiu YH, Chen ZJ. The cGAS-cGAMP-STING pathway of cytosolic DNA sensing and signaling. Mol Cell 2014; 54:289-96. [PMID: 24766893 DOI: 10.1016/j.molcel.2014.03.040] [Citation(s) in RCA: 672] [Impact Index Per Article: 67.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The innate immune system deploys a variety of sensors to detect signs of infection. Nucleic acids represent a major class of pathogen signatures that can trigger robust immune responses. The presence of DNA in the cytoplasm of mammalian cells is a danger signal that activates innate immune responses; however, how cytosolic DNA triggers these responses remained unclear until recently. In this review, we focus on the mechanism of DNA sensing by the newly discovered cGAS-cGAMP-STING pathway and highlight recent progress in dissecting the in vivo functions of this pathway in immune defense as well as autoimmunity.
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Affiliation(s)
- Xin Cai
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yu-Hsin Chiu
- Beth Israel Deaconess Medical Center, Boston, MA 02115, USA.
| | - Zhijian J Chen
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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698
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Zhu J, Zhang Y, Ghosh A, Cuevas RA, Forero A, Dhar J, Ibsen MS, Schmid-Burgk JL, Schmidt T, Ganapathiraju MK, Fujita T, Hartmann R, Barik S, Hornung V, Coyne CB, Sarkar SN. Antiviral activity of human OASL protein is mediated by enhancing signaling of the RIG-I RNA sensor. Immunity 2014; 40:936-48. [PMID: 24931123 PMCID: PMC4101812 DOI: 10.1016/j.immuni.2014.05.007] [Citation(s) in RCA: 171] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 04/28/2014] [Indexed: 02/07/2023]
Abstract
Virus infection is sensed in the cytoplasm by retinoic acid-inducible gene I (RIG-I, also known as DDX58), which requires RNA and polyubiquitin binding to induce type I interferon (IFN) and activate cellular innate immunity. We show that the human IFN-inducible oligoadenylate synthetases-like (OASL) protein has antiviral activity and mediates RIG-I activation by mimicking polyubiquitin. Loss of OASL expression reduced RIG-I signaling and enhanced virus replication in human cells. Conversely, OASL expression suppressed replication of a number of viruses in a RIG-I-dependent manner and enhanced RIG-I-mediated IFN induction. OASL interacted and colocalized with RIG-I, and through its C-terminal ubiquitin-like domain specifically enhanced RIG-I signaling. Bone-marrow-derived macrophages from mice deficient for Oasl2 showed that among the two mouse orthologs of human OASL, Oasl2 is functionally similar to human OASL. Our findings show a mechanism by which human OASL contributes to host antiviral responses by enhancing RIG-I activation.
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Affiliation(s)
- Jianzhong Zhu
- Cancer Virology Program, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Yugen Zhang
- Cancer Virology Program, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Arundhati Ghosh
- Cancer Virology Program, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Rolando A Cuevas
- Cancer Virology Program, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Adriana Forero
- Cancer Virology Program, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Jayeeta Dhar
- Center for Gene Regulation in Health and Disease, and Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA
| | - Mikkel Søes Ibsen
- Department of Molecular Biology, Aarhus University, Aarhus 8000, Denmark
| | | | - Tobias Schmidt
- Institute for Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn 53127, Germany
| | - Madhavi K Ganapathiraju
- Department of Biomedical Informatics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Takashi Fujita
- Laboratory of Molecular Genetics, Kyoto University, Kyoto 606-8507, Japan
| | - Rune Hartmann
- Department of Molecular Biology, Aarhus University, Aarhus 8000, Denmark
| | - Sailen Barik
- Center for Gene Regulation in Health and Disease, and Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA
| | - Veit Hornung
- Institute for Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn 53127, Germany
| | - Carolyn B Coyne
- Cancer Virology Program, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Saumendra N Sarkar
- Cancer Virology Program, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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699
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Abstract
Mammalian cells detect foreign DNA introduced as free DNA or as a result of microbial infection, leading to the induction of innate immune responses that block microbial replication and the activation of mechanisms that epigenetically silence the genes encoded by the foreign DNA. A number of DNA sensors localized to a variety of sites within the cell have been identified, and this review focuses on the mechanisms that detect viral DNA and how the resulting responses affect viral infections. Viruses have evolved mechanisms that inhibit these host sensors and signaling pathways, and the study of these antagonistic viral strategies has provided insight into the mechanisms of these host responses. The field of cellular sensing of foreign DNA is in its infancy, but our currently limited knowledge has raised a number of important questions for study.
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Affiliation(s)
- Megan H Orzalli
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115;
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700
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Iwasaki A, Pillai PS. Innate immunity to influenza virus infection. Nat Rev Immunol 2014; 14:315-28. [PMID: 24762827 DOI: 10.1038/nri3665] [Citation(s) in RCA: 767] [Impact Index Per Article: 76.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Influenza viruses are a major pathogen of both humans and animals. Recent studies using gene-knockout mice have led to an in-depth understanding of the innate sensors that detect influenza virus infection in a variety of cell types. Signalling downstream of these sensors induces distinct sets of effector mechanisms that block virus replication and promote viral clearance by inducing innate and adaptive immune responses. In this Review, we discuss the various ways in which the innate immune system uses pattern recognition receptors to detect and respond to influenza virus infection. We consider whether the outcome of innate sensor stimulation promotes antiviral resistance or disease tolerance, and propose rational treatment strategies for the acute respiratory disease that is caused by influenza virus infection.
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Affiliation(s)
- Akiko Iwasaki
- Department of Immunobiology, Yale University School of Medicine, 300 Cedar Street, New Haven, Connecticut 06520, USA
| | - Padmini S Pillai
- Department of Immunobiology, Yale University School of Medicine, 300 Cedar Street, New Haven, Connecticut 06520, USA
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