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Melo-Silva CR, Sigal LJ. Innate and adaptive immune responses that control lymph-borne viruses in the draining lymph node. Cell Mol Immunol 2024; 21:999-1007. [PMID: 38918577 PMCID: PMC11364670 DOI: 10.1038/s41423-024-01188-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Accepted: 05/23/2024] [Indexed: 06/27/2024] Open
Abstract
The interstitial fluids in tissues are constantly drained into the lymph nodes (LNs) as lymph through afferent lymphatic vessels and from LNs into the blood through efferent lymphatics. LNs are strategically positioned and have the appropriate cellular composition to serve as sites of adaptive immune initiation against invading pathogens. However, for lymph-borne viruses, which disseminate from the entry site to other tissues through the lymphatic system, immune cells in the draining LN (dLN) also play critical roles in curbing systemic viral dissemination during primary and secondary infections. Lymph-borne viruses in tissues can be transported to dLNs as free virions in the lymph or within infected cells. Regardless of the entry mechanism, infected myeloid antigen-presenting cells, including various subtypes of dendritic cells, inflammatory monocytes, and macrophages, play a critical role in initiating the innate immune response within the dLN. This innate immune response involves cellular crosstalk between infected and bystander innate immune cells that ultimately produce type I interferons (IFN-Is) and other cytokines and recruit inflammatory monocytes and natural killer (NK) cells. IFN-I and NK cell cytotoxicity can restrict systemic viral spread during primary infections and prevent serious disease. Additionally, the memory CD8+ T-cells that reside or rapidly migrate to the dLN can contribute to disease prevention during secondary viral infections. This review explores the intricate innate immune responses orchestrated within dLNs that contain primary viral infections and the role of memory CD8+ T-cells following secondary infection or CD8+ T-cell vaccination.
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Affiliation(s)
- Carolina R Melo-Silva
- Department of Microbiology and Immunology, Thomas Jefferson University, Bluemle Life Sciences Building Room 709, 233 South 10th Street, Philadelphia, PA, 19107, USA.
| | - Luis J Sigal
- Department of Microbiology and Immunology, Thomas Jefferson University, Bluemle Life Sciences Building Room 709, 233 South 10th Street, Philadelphia, PA, 19107, USA.
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2
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Suptela AJ, Radwan Y, Richardson C, Yan S, Afonin KA, Marriott I. cGAS Mediates the Inflammatory Responses of Human Microglial Cells to Genotoxic DNA Damage. Inflammation 2024; 47:822-836. [PMID: 38148453 PMCID: PMC11073916 DOI: 10.1007/s10753-023-01946-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/01/2023] [Accepted: 12/07/2023] [Indexed: 12/28/2023]
Abstract
Genomic instability is a key driving force for the development and progression of many age-related neurodegenerative diseases and central nervous system (CNS) cancers. Recently, the cytosolic DNA sensor, cyclic GMP-AMP synthase (cGAS), has been shown to detect and respond to self-DNA accumulation resulting from DNA damaging insults in peripheral cell types. cGAS has been shown to be important in the responses of microglia to DNA viruses and amyloid beta, and we have reported that it underlies the responses of human microglia to exogenous DNA. However, the role of this cytosolic sensor in the detection of self-DNA by glia is poorly understood and its ability to mediate the cellular responses of human microglia to genotoxic DNA damage has not been established. Here, we describe the ability of ionizing radiation and oxidative stress to elicit genomic DNA damage in human microglial cells and to stimulate the production of key inflammatory mediators by these cells in an NF-kB dependent manner. Importantly, we have utilized CRISPR/Cas9 and siRNA-mediated knockdown approaches and a pharmacological inhibitor of the cGAS adaptor protein stimulator of interferon genes (STING) to demonstrate that the cGAS-STING pathway plays a critical role in the generation of these microglial immune responses to such genotoxic insults. Together, these studies support the notion that cGAS mediates the detection of cytosolic self-DNA by microglia, providing a potential mechanism linking genomic instability to the development of CNS cancers and neurodegenerative disorders.
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Affiliation(s)
- Alexander J Suptela
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC, 28223, USA
| | - Yasmine Radwan
- Department of Chemistry, University of North Carolina at Charlotte, Charlotte, NC, USA
| | - Christine Richardson
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC, 28223, USA
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC, 28223, USA
| | - Kirill A Afonin
- Department of Chemistry, University of North Carolina at Charlotte, Charlotte, NC, USA
| | - Ian Marriott
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC, 28223, USA.
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3
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Yang N, Wang Y, Dai P, Li T, Zierhut C, Tan A, Zhang T, Xiang JZ, Ordureau A, Funabiki H, Chen Z, Deng L. Vaccinia E5 is a major inhibitor of the DNA sensor cGAS. Nat Commun 2023; 14:2898. [PMID: 37217469 PMCID: PMC10201048 DOI: 10.1038/s41467-023-38514-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 05/05/2023] [Indexed: 05/24/2023] Open
Abstract
The DNA sensor cyclic GMP-AMP synthase (cGAS) is critical in host antiviral immunity. Vaccinia virus (VACV) is a large cytoplasmic DNA virus that belongs to the poxvirus family. How vaccinia virus antagonizes the cGAS-mediated cytosolic DNA-sensing pathway is not well understood. In this study, we screened 80 vaccinia genes to identify potential viral inhibitors of the cGAS/Stimulator of interferon gene (STING) pathway. We discovered that vaccinia E5 is a virulence factor and a major inhibitor of cGAS. E5 is responsible for abolishing cGAMP production during vaccinia virus (Western Reserve strain) infection of dendritic cells. E5 localizes to the cytoplasm and nucleus of infected cells. Cytosolic E5 triggers ubiquitination of cGAS and proteasome-dependent degradation via interacting with cGAS. Deleting the E5R gene from the Modified vaccinia virus Ankara (MVA) genome strongly induces type I IFN production by dendritic cells (DCs) and promotes DC maturation, and thereby improves antigen-specific T cell responses.
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Affiliation(s)
- Ning Yang
- Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA.
| | - Yi Wang
- Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Peihong Dai
- Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Tuo Li
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Christian Zierhut
- Laboratory of Chromosome and Cell Biology, The Rockefeller University, New York, NY, 10065, USA
- The Institute of Cancer Research, London, SW3 6JB, UK
| | - Adrian Tan
- Genomic Resources Core Facility, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Tuo Zhang
- Genomic Resources Core Facility, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Jenny Zhaoying Xiang
- Genomic Resources Core Facility, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Alban Ordureau
- Cell Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Hironori Funabiki
- Laboratory of Chromosome and Cell Biology, The Rockefeller University, New York, NY, 10065, USA
| | - Zhijian Chen
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Liang Deng
- Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA.
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA.
- Weill Cornell Medical College, New York, NY, 10065, USA.
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Resistance To Poxvirus Lethality Does Not Require the Necroptosis Proteins RIPK3 or MLKL. J Virol 2023; 97:e0194522. [PMID: 36651749 PMCID: PMC9973014 DOI: 10.1128/jvi.01945-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Receptor-interacting protein kinase 3 (RIPK3) and mixed lineage kinase domain-like pseudokinase (MLKL) are proteins that are critical for necroptosis, a mechanism of programmed cell death that is both activated when apoptosis is inhibited and thought to be antiviral. Here, we investigated the role of RIPK3 and MLKL in controlling the Orthopoxvirus ectromelia virus (ECTV), a natural pathogen of the mouse. We found that C57BL/6 (B6) mice deficient in RIPK3 (Ripk3-/-) or MLKL (Mlkl-/-) were as susceptible as wild-type (WT) B6 mice to ECTV lethality after low-dose intraperitoneal infection and were as resistant as WT B6 mice after ECTV infection through the natural footpad route. Additionally, after footpad infection, Mlkl-/- mice, but not Ripk3-/- mice, endured lower viral titers than WT mice in the draining lymph node (dLN) at three days postinfection and in the spleen or in the liver at seven days postinfection. Despite the improved viral control, Mlkl-/- mice did not differ from WT mice in the expression of interferons or interferon-stimulated genes or in the recruitment of natural killer (NK) cells and inflammatory monocytes (iMOs) to the dLN. Additionally, the CD8 T-cell responses in Mlkl-/- and WT mice were similar, even though in the dLNs of Mlkl-/- mice, professional antigen-presenting cells were more heavily infected. Finally, the histopathology in the livers of Mlkl-/- and WT mice at 7 dpi did not differ. Thus, the mechanism of the increased virus control by Mlkl-/- mice remains to be defined. IMPORTANCE The molecules RIPK3 and MLKL are required for necroptotic cell death, which is widely thought of as an antiviral mechanism. Here we show that C57BL/6 (B6) mice deficient in RIPK3 or MLKL are as susceptible as WT B6 mice to ECTV lethality after a low-dose intraperitoneal infection and are as resistant as WT B6 mice after ECTV infection through the natural footpad route. Mice deficient in MLKL are more efficient than WT mice at controlling virus loads in various organs. This improved viral control is not due to enhanced interferon, natural killer cell, or CD8 T-cell responses. Overall, the data indicate that deficiencies in the molecules that are critical to necroptosis do not necessarily result in worse outcomes following viral infection and may improve virus control.
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Saghazadeh A, Rezaei N. Poxviruses and the immune system: Implications for monkeypox virus. Int Immunopharmacol 2022; 113:109364. [PMID: 36283221 PMCID: PMC9598838 DOI: 10.1016/j.intimp.2022.109364] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 10/09/2022] [Accepted: 10/14/2022] [Indexed: 11/05/2022]
Abstract
Poxviruses (PXVs) are mostly known for the variola virus, being the cause of smallpox; however, re-emerging PXVs have also shown a great capacity to develop outbreaks of pox-like infections in humans. The situation is alarming; PXV outbreaks have been involving both endemic and non-endemic areas in recent decades. Stopped smallpox vaccination is a reason offered mainly for this changing epidemiology that implies the protective role of immunity in the pathology of PXV infections. The immune system recognizes PXVs and elicits responses, but PXVs can antagonize these responses. Here, we briefly review the immunology of PXV infections, with emphasis on the role of pattern-recognition receptors, macrophages, and natural killer cells in the early response to PXV infections and PXVs’ strategies influencing these responses, as well as taking a glance at other immune cells, which discussion over them mainly occurs in association with PXV immunization rather than PXV infection. Throughout the review, numerous evasion mechanisms are highlighted, which might have implications for designing specific immunotherapies for PXV in the future.
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Affiliation(s)
- Amene Saghazadeh
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Systematic Review and Meta-analysis Expert Group (SRMEG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Nima Rezaei
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Tehran, Iran.
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6
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Rahman MM, McFadden G. Role of cytokines in poxvirus host tropism and adaptation. Curr Opin Virol 2022; 57:101286. [PMID: 36427482 PMCID: PMC9704024 DOI: 10.1016/j.coviro.2022.101286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/19/2022] [Accepted: 10/26/2022] [Indexed: 11/23/2022]
Abstract
Poxviruses are a diverse family of double-stranded DNA viruses that cause mild-to-severe disease in selective hosts, including humans. Although most poxviruses are restricted to their hosts, some members can leap host species and cause zoonotic diseases and, therefore, are genuine threats to human and animal health. The recent global spread of monkeypox in humans suggests that zoonotic poxviruses can adapt to a new host, spread rapidly in the new host, and evolve to better evade host innate barriers. Unlike many other viruses, poxviruses express an extensive repertoire of self-defense proteins that play a vital role in the evasion of host innate and adaptive immune responses in their newest host species. The function of these viral immune modulators and host-specific cytokine responses can result in different host tropism and poxvirus disease progression. Here, we review the role of different cytokines that control poxvirus host tropism and adaptation.
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Melo-Silva CR, Roman MI, Knudson CJ, Tang L, Xu RH, Tassetto M, Dolan P, Andino R, Sigal LJ. Interferon partly dictates a divergent transcriptional response in poxvirus-infected and bystander inflammatory monocytes. Cell Rep 2022; 41:111676. [PMID: 36417857 PMCID: PMC9798443 DOI: 10.1016/j.celrep.2022.111676] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 09/07/2022] [Accepted: 10/25/2022] [Indexed: 11/23/2022] Open
Abstract
Inflammatory monocytes (iMOs) and B cells are the main targets of the poxvirus ectromelia virus (ECTV) in the lymph nodes of mice and play distinct roles in surviving the infection. Infected and bystander iMOs control ECTV's systemic spread, preventing early death, while B cells make antibodies that eliminate ECTV. Our work demonstrates that within an infected animal that survives ECTV infection, intrinsic and bystander infection of iMOs and B cells differentially control the transcription of genes important for immune cell function and, perhaps, cell identity. Bystander cells upregulate metabolism, antigen presentation, and interferon-stimulated genes. Infected cells downregulate many cell-type-specific genes and upregulate transcripts typical of non-immune cells. Bystander (Bys) and infected (Inf) iMOs non-redundantly contribute to the cytokine milieu and the interferon response. Furthermore, we uncover how type I interferon (IFN-I) or IFN-γ signaling differentially regulates immune pathways in Inf and Bys iMOs and that, at steady state, IFN-I primes iMOs for rapid IFN-I production and antigen presentation.
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Affiliation(s)
- Carolina R. Melo-Silva
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Marisa I. Roman
- Department of Physics, St. Joseph University, Philadelphia PA 19131, USA
| | - Cory J. Knudson
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107, USA,GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, PA 19426, USA
| | - Lingjuan Tang
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Ren-Huan Xu
- Advanced RNA Vaccine Technologies, Inc., 12358 Parklawn Dr, North Bethesda, MD 20852, USA
| | - Michel Tassetto
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Patrick Dolan
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94158, USA,Laboratory of Viral Diseases, NIAID, NIH, Bethesda, MD 20892-3210, USA
| | - Raul Andino
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Luis J. Sigal
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107, USA,Lead contact,Correspondence:
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8
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Lung type II alveolar epithelial cells collaborate with CCR2+ inflammatory monocytes in host defense against poxvirus infection. Nat Commun 2022; 13:1671. [PMID: 35351885 PMCID: PMC8964745 DOI: 10.1038/s41467-022-29308-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 03/02/2022] [Indexed: 12/24/2022] Open
Abstract
The pulmonary immune system consists of a network of tissue-resident cells as well as immune cells that are recruited to the lungs during infection and/or inflammation. How these immune components function during an acute poxvirus infection is not well understood. Intranasal infection of mice with vaccinia virus causes lethal pneumonia and systemic dissemination. Here we report that vaccinia C7 is a crucial virulence factor that blocks activation of the transcription factor IRF3. We provide evidence that type II alveolar epithelial cells (AECIIs) respond to pulmonary infection of vaccinia virus by inducing IFN-β and IFN-stimulated genes via the activation of the MDA5 and STING-mediated nucleic acid-sensing pathways and the type I IFN positive feedback loop. This leads to the recruitment and activation of CCR2+ inflammatory monocytes in the infected lungs and subsequent differentiation into Lyve1− interstitial macrophages (Lyve1− IMs), which efficiently engulf viral particles and block viral replication. Our results provide insights into how innate immune sensing of viral infection by lung AECIIs influences the activation and differentiation of CCR2+ inflammatory monocytes to defend against pulmonary poxvirus infection. Smallpox is a highly contagious respiratory pathogen associated with a high mortality rate. Here the authors utilize a mouse model of intranasal vaccinia virus infection and show a C7 gene encoded virulence factor attenuates type I IFN release by lung type II alveolar epithelial cells and reduces lung inflammatory monocyte responses.
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9
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Melo-Silva CR, Alves-Peixoto P, Heath N, Tang L, Montoya B, Knudson CJ, Stotesbury C, Ferez M, Wong E, Sigal LJ. Resistance to lethal ectromelia virus infection requires Type I interferon receptor in natural killer cells and monocytes but not in adaptive immune or parenchymal cells. PLoS Pathog 2021; 17:e1009593. [PMID: 34015056 PMCID: PMC8172060 DOI: 10.1371/journal.ppat.1009593] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 06/02/2021] [Accepted: 04/28/2021] [Indexed: 11/18/2022] Open
Abstract
Type I interferons (IFN-I) are antiviral cytokines that signal through the ubiquitous IFN-I receptor (IFNAR). Following footpad infection with ectromelia virus (ECTV), a mouse-specific pathogen, C57BL/6 (B6) mice survive without disease, while B6 mice broadly deficient in IFNAR succumb rapidly. We now show that for survival to ECTV, only hematopoietic cells require IFNAR expression. Survival to ECTV specifically requires IFNAR in both natural killer (NK) cells and monocytes. However, intrinsic IFNAR signaling is not essential for adaptive immune cell responses or to directly protect non-hematopoietic cells such as hepatocytes, which are principal ECTV targets. Mechanistically, IFNAR-deficient NK cells have reduced cytolytic function, while lack of IFNAR in monocytes dampens IFN-I production and hastens virus dissemination. Thus, during a pathogenic viral infection, IFN-I coordinates innate immunity by stimulating monocytes in a positive feedback loop and by inducing NK cell cytolytic function.
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Affiliation(s)
- Carolina R. Melo-Silva
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Pedro Alves-Peixoto
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Natasha Heath
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Lingjuan Tang
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Brian Montoya
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Cory J. Knudson
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Colby Stotesbury
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Maria Ferez
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Eric Wong
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Luis J. Sigal
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Cytosolic Sensors for Pathogenic Viral and Bacterial Nucleic Acids in Fish. Int J Mol Sci 2020; 21:ijms21197289. [PMID: 33023222 PMCID: PMC7582293 DOI: 10.3390/ijms21197289] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 09/29/2020] [Indexed: 12/11/2022] Open
Abstract
Recognition of the non-self signature of invading pathogens is a crucial step for the initiation of the innate immune mechanisms of the host. The host response to viral and bacterial infection involves sets of pattern recognition receptors (PRRs), which bind evolutionarily conserved pathogen structures, known as pathogen-associated molecular patterns (PAMPs). Recent advances in the identification of different types of PRRs in teleost fish revealed a number of cytosolic sensors for recognition of viral and bacterial nucleic acids. These are DExD/H-box RNA helicases including a group of well-characterized retinoic acid inducible gene I (RIG-I)-like receptors (RLRs) and non-RLR DExD/H-box RNA helicases (e.g., DDX1, DDX3, DHX9, DDX21, DHX36 and DDX41) both involved in recognition of viral RNAs. Another group of PRRs includes cytosolic DNA sensors (CDSs), such as cGAS and LSm14A involved in recognition of viral and intracellular bacterial dsDNAs. Moreover, dsRNA-sensing protein kinase R (PKR), which has a role in antiviral immune responses in higher vertebrates, has been identified in fish. Additionally, fish possess a novel PKR-like protein kinase containing Z-DNA binding domain, known as PKZ. Here, we review the current knowledge concerning cytosolic sensors for recognition of viral and bacterial nucleic acids in teleosts.
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El-Jesr M, Teir M, Maluquer de Motes C. Vaccinia Virus Activation and Antagonism of Cytosolic DNA Sensing. Front Immunol 2020; 11:568412. [PMID: 33117352 PMCID: PMC7559579 DOI: 10.3389/fimmu.2020.568412] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/24/2020] [Indexed: 12/16/2022] Open
Abstract
Cells express multiple molecules aimed at detecting incoming virus and infection. Recognition of virus infection leads to the production of cytokines, chemokines and restriction factors that limit virus replication and activate an adaptive immune response offering long-term protection. Recognition of cytosolic DNA has become a central immune sensing mechanism involved in infection, autoinflammation, and cancer immunotherapy. Vaccinia virus (VACV) is the prototypic member of the family Poxviridae and the vaccine used to eradicate smallpox. VACV harbors enormous potential as a vaccine vector and several attenuated strains are currently being developed against infectious diseases. In addition, VACV has emerged as a popular oncolytic agent due to its cytotoxic capacity even in hypoxic environments. As a poxvirus, VACV is an unusual virus that replicates its large DNA genome exclusively in the cytoplasm of infected cells. Despite producing large amounts of cytosolic DNA, VACV efficiently suppresses the subsequent innate immune response by deploying an arsenal of proteins with capacity to disable host antiviral signaling, some of which specifically target cytosolic DNA sensing pathways. Some of these strategies are conserved amongst orthopoxviruses, whereas others are seemingly unique to VACV. In this review we provide an overview of the VACV replicative cycle and discuss the recent advances on our understanding of how VACV induces and antagonizes innate immune activation via cytosolic DNA sensing pathways. The implications of these findings in the rational design of vaccines and oncolytics based on VACV are also discussed.
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Affiliation(s)
- Misbah El-Jesr
- Department of Microbial Sciences, University of Surrey, Guildford, United Kingdom
| | - Muad Teir
- Department of Microbial Sciences, University of Surrey, Guildford, United Kingdom
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12
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Jeffries AM, Marriott I. Cytosolic DNA Sensors and CNS Responses to Viral Pathogens. Front Cell Infect Microbiol 2020; 10:576263. [PMID: 33042875 PMCID: PMC7525022 DOI: 10.3389/fcimb.2020.576263] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/12/2020] [Indexed: 12/17/2022] Open
Abstract
Viral central nervous system (CNS) infections can lead to life threatening encephalitis and long-term neurological deficits in survivors. Resident CNS cell types, such as astrocytes and microglia, are known to produce key inflammatory and antiviral mediators following infection with neurotropic DNA viruses. However, the mechanisms by which glia mediate such responses remain poorly understood. Recently, a class of intracellular pattern recognition receptors (PRRs), collectively known as DNA sensors, have been identified in both leukocytic and non-leukocytic cell types. The ability of such DNA sensors to initiate immune mediator production and contribute to infection resolution in the periphery is increasingly recognized, but our understanding of their role in the CNS remains limited at best. In this review, we describe the evidence for the expression and functionality of DNA sensors in resident brain cells, with a focus on their role in neurotropic virus infections. The available data indicate that glia and neurons can constitutively express, and/or can be induced to express, various disparate DNA sensing molecules previously described in peripheral cell types. Furthermore, multiple lines of investigation suggest that these sensors are functional in resident CNS cells and are required for innate immune responses to viral infections. However, it is less clear whether DNA sensormediated glial responses are beneficial or detrimental, and the answer to this question appears to dependent on the context of the infection with regard to the identity of the pathogen, host cell type, and host species. Defining such parameters will be essential if we are to successfully target these molecules to limit damaging inflammation while allowing beneficial host responses to improve patient outcomes.
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Affiliation(s)
- Austin M Jeffries
- Department of Biological Sciences, The University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Ian Marriott
- Department of Biological Sciences, The University of North Carolina at Charlotte, Charlotte, NC, United States
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13
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Hernáez B, Alonso G, Georgana I, El-Jesr M, Martín R, Shair KHY, Fischer C, Sauer S, Maluquer de Motes C, Alcamí A. Viral cGAMP nuclease reveals the essential role of DNA sensing in protection against acute lethal virus infection. SCIENCE ADVANCES 2020; 6:6/38/eabb4565. [PMID: 32948585 PMCID: PMC7500930 DOI: 10.1126/sciadv.abb4565] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
Cells contain numerous immune sensors to detect virus infection. The cyclic GMP-AMP (cGAMP) synthase (cGAS) recognizes cytosolic DNA and activates innate immune responses via stimulator of interferon genes (STING), but the impact of DNA sensing pathways on host protective responses has not been fully defined. We demonstrate that cGAS/STING activation is required to resist lethal poxvirus infection. We identified viral Schlafen (vSlfn) as the main STING inhibitor, and ectromelia virus was severely attenuated in the absence of vSlfn. Both vSlfn-mediated virulence and STING inhibitory activity were mapped to the recently discovered poxin cGAMP nuclease domain. Animals were protected from subcutaneous, respiratory, and intravenous infection in the absence of vSlfn, and interferon was the main antiviral protective mechanism controlled by the DNA sensing pathway. Our findings support the idea that manipulation of DNA sensing is an efficient therapeutic strategy in diseases triggered by viral infection or tissue damage-mediated release of self-DNA.
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Affiliation(s)
- Bruno Hernáez
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Madrid, Spain
| | - Graciela Alonso
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Madrid, Spain
| | - Iliana Georgana
- Department of Microbial Sciences, University of Surrey, Guildford, UK
| | - Misbah El-Jesr
- Department of Microbial Sciences, University of Surrey, Guildford, UK
| | - Rocío Martín
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Madrid, Spain
| | - Kathy H Y Shair
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Cornelius Fischer
- Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
- Max Delbrück Center for Molecular Medicine, Berlin Institute of Health, Berlin, Germany
| | - Sascha Sauer
- Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
- Max Delbrück Center for Molecular Medicine, Berlin Institute of Health, Berlin, Germany
| | | | - Antonio Alcamí
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Madrid, Spain.
- Department of Medicine, University of Cambridge, Cambridge, UK
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Stotesbury C, Wong EB, Tang L, Montoya B, Knudson CJ, Melo‐Silva CR, Sigal LJ. Defective early innate immune response to ectromelia virus in the draining lymph nodes of aged mice due to impaired dendritic cell accumulation. Aging Cell 2020; 19:e13170. [PMID: 32657004 PMCID: PMC7433008 DOI: 10.1111/acel.13170] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 04/11/2020] [Accepted: 05/13/2020] [Indexed: 12/14/2022] Open
Abstract
It is known that aging decreases natural resistance to viral diseases due to dysfunctional innate and adaptive immune responses, but the nature of these dysfunctions, particularly in regard to innate immunity, is not well understood. We have previously shown that C57BL/6J (B6) mice lose their natural resistance to footpad infection with ectromelia virus (ECTV) due to impaired maturation and recruitment of natural killer (NK) cells to the draining popliteal lymph node (dLN). More recently, we have also shown that in young B6 mice infected with ECTV, the recruitment of NK cells is dependent on a complex cascade whereby migratory dendritic cells (mDCs) traffic from the skin to the dLN, where they produce CCL2 and CCL7 to recruit inflammatory monocytes (iMOs). In the dLN, mDCs also upregulate NKG2D ligands to induce interferon gamma (IFN-γ) expression by group 1 innate lymphoid cells (G1-ILCs), mostly NK in cells but also some ILC1. In response to the IFN-γ, the incoming uninfected iMOs secret CXCL9 to recruit the critical NK cells. Here, we show that in aged B6 mice, the trafficking of mDCs to the dLN in response to ECTV is decreased, resulting in impaired IFN-γ expression by G1-ILCs, reduced accumulation of iMOs, and attenuated CXCL9 production by iMOs, which likely contributes to decrease in NK cell recruitment. Together, these data indicate that defects in the mDC response to viral infection during aging result in a reduced innate immune response in the dLN and contribute to increased susceptibility to viral disease in the aged.
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Affiliation(s)
- Colby Stotesbury
- Department of Microbiology and Immunology Thomas Jefferson University Philadelphia PA USA
| | - Eric B. Wong
- Department of Microbiology and Immunology Thomas Jefferson University Philadelphia PA USA
| | - Lingjuan Tang
- Department of Microbiology and Immunology Thomas Jefferson University Philadelphia PA USA
| | - Brian Montoya
- Department of Microbiology and Immunology Thomas Jefferson University Philadelphia PA USA
| | - Cory J. Knudson
- Department of Microbiology and Immunology Thomas Jefferson University Philadelphia PA USA
| | - Carolina R. Melo‐Silva
- Department of Microbiology and Immunology Thomas Jefferson University Philadelphia PA USA
| | - Luis J. Sigal
- Department of Microbiology and Immunology Thomas Jefferson University Philadelphia PA USA
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