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Liu S, Heumüller SE, Hossinger A, Müller SA, Buravlova O, Lichtenthaler SF, Denner P, Vorberg IM. Reactivated endogenous retroviruses promote protein aggregate spreading. Nat Commun 2023; 14:5034. [PMID: 37596282 PMCID: PMC10439213 DOI: 10.1038/s41467-023-40632-z] [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: 06/21/2022] [Accepted: 08/02/2023] [Indexed: 08/20/2023] Open
Abstract
Prion-like spreading of protein misfolding is a characteristic of neurodegenerative diseases, but the exact mechanisms of intercellular protein aggregate dissemination remain unresolved. Evidence accumulates that endogenous retroviruses, remnants of viral germline infections that are normally epigenetically silenced, become upregulated in neurodegenerative diseases such as amyotrophic lateral sclerosis and tauopathies. Here we uncover that activation of endogenous retroviruses affects prion-like spreading of proteopathic seeds. We show that upregulation of endogenous retroviruses drastically increases the dissemination of protein aggregates between cells in culture, a process that can be inhibited by targeting the viral envelope protein or viral protein processing. Human endogenous retrovirus envelopes of four different clades also elevate intercellular spreading of proteopathic seeds, including pathological Tau. Our data support a role of endogenous retroviruses in protein misfolding diseases and suggest that antiviral drugs could represent promising candidates for inhibiting protein aggregate spreading.
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Affiliation(s)
- Shu Liu
- German Center for Neurodegenerative Diseases Bonn (DZNE), Venusberg Campus 1/ 99, 53127, Bonn, Germany
- German Federal Institute for Risk Assessment (BfR), German Centre for the Protection of Laboratory Animals (Bf3R), Max-Dohrn-Straße 8-10, 10589, Berlin, Germany
| | | | - André Hossinger
- German Center for Neurodegenerative Diseases Bonn (DZNE), Venusberg Campus 1/ 99, 53127, Bonn, Germany
| | - Stephan A Müller
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Oleksandra Buravlova
- German Center for Neurodegenerative Diseases Bonn (DZNE), Venusberg Campus 1/ 99, 53127, Bonn, Germany
| | - Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Philip Denner
- German Center for Neurodegenerative Diseases Bonn (DZNE), Venusberg Campus 1/ 99, 53127, Bonn, Germany
| | - Ina M Vorberg
- German Center for Neurodegenerative Diseases Bonn (DZNE), Venusberg Campus 1/ 99, 53127, Bonn, Germany.
- Department of Neurology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany, Venusberg-Campus 1, 53127, Bonn, Germany.
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2
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Rangel SC, da Silva MD, da Silva AL, dos Santos JDMB, Neves LM, Pedrosa A, Rodrigues FM, Trettel CDS, Furtado GE, de Barros MP, Bachi ALL, Romano CM, Nali LHDS. Human endogenous retroviruses and the inflammatory response: A vicious circle associated with health and illness. Front Immunol 2022; 13:1057791. [PMID: 36518758 PMCID: PMC9744114 DOI: 10.3389/fimmu.2022.1057791] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/31/2022] [Indexed: 11/24/2022] Open
Abstract
Human Endogenous Retroviruses (HERVs) are derived from ancient exogenous retroviral infections that have infected our ancestors' germline cells, underwent endogenization process, and were passed throughout the generations by retrotransposition and hereditary transmission. HERVs comprise 8% of the human genome and are critical for several physiological activities. Yet, HERVs reactivation is involved in pathological process as cancer and autoimmune diseases. In this review, we summarize the multiple aspects of HERVs' role within the human genome, as well as virological and molecular aspects, and their fusogenic property. We also discuss possibilities of how the HERVs are possibly transactivated and participate in modulating the inflammatory response in health conditions. An update on their role in several autoimmune, inflammatory, and aging-related diseases is also presented.
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Affiliation(s)
- Sara Coelho Rangel
- UNISA Research Center, Universidade Santo Amaro, Post-Graduation in Health Sciences, São Paulo, Brazil
| | | | - Amanda Lopes da Silva
- Laboratório de Virologia, Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, São Paulo, Brazil
| | | | - Lucas Melo Neves
- UNISA Research Center, Universidade Santo Amaro, Post-Graduation in Health Sciences, São Paulo, Brazil
| | - Ana Pedrosa
- CNC-Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, (3004-504), Coimbra, Portugal
| | | | - Caio dos Santos Trettel
- Interdisciplinary Program in Health Sciences, Institute of Physical Activity Sciences and Sports (ICAFE), Cruzeiro do Sul University, São Paulo, Brazil
| | - Guilherme Eustáquio Furtado
- Polytechnic Institute of Coimbra, Applied Research Institute, Rua da Misericórdia, Lagar dos Cortiços – S. Martinho do Bispo, Coimbra, Portugal
| | - Marcelo Paes de Barros
- Interdisciplinary Program in Health Sciences, Institute of Physical Activity Sciences and Sports (ICAFE), Cruzeiro do Sul University, São Paulo, Brazil
| | - André Luis Lacerda Bachi
- UNISA Research Center, Universidade Santo Amaro, Post-Graduation in Health Sciences, São Paulo, Brazil
| | - Camila Malta Romano
- Laboratório de Virologia, Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, São Paulo, Brazil,Hospital das Clínicas HCFMUSP (LIM52), Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Luiz Henrique Da Silva Nali
- UNISA Research Center, Universidade Santo Amaro, Post-Graduation in Health Sciences, São Paulo, Brazil,*Correspondence: Luiz Henrique Da Silva Nali, ;
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3
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Budd RC, Scharer CD, Barrantes-Reynolds R, Legunn S, Fortner KA. T Cell Homeostatic Proliferation Promotes a Redox State That Drives Metabolic and Epigenetic Upregulation of Inflammatory Pathways in Lupus. Antioxid Redox Signal 2022; 36:410-422. [PMID: 34328790 PMCID: PMC8982120 DOI: 10.1089/ars.2021.0078] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Significance: Numerous abnormalities in T cells have been described in patients with systemic lupus erythematosus (SLE), including lymphopenia, DNA demethylation, expression of endogenous retroviruses (ERVs), increased cell death, enlarged mitochondria, production of reactive oxygen species (ROS), and the appearance of unusual CD4-CD8- T cells. Our studies propose a model in which accelerated homeostatic proliferation of T cells promotes an epigenetic and metabolic program, leading to this cluster of abnormalities. Recent Advances: Growing knowledge of the innate immune disorders in SLE has included increased mitochondrial size and ROS production that induces oligomerization of the mitochondrial antiviral signaling (MAVS) protein and type I interferon production, as well as DNA demethylation, upregulation of inflammatory genes, and expression of certain ERVs in SLE peripheral blood mononuclear cells. All these events are part of the cellular program that occurs during homeostatic proliferation of T cells. Evidence from a murine model of SLE as well as in human SLE reveals that increased T cell homeostatic proliferation may be a driving factor in these processes. Critical Issues: Despite extensive knowledge of the myriad autoantibodies in SLE and other immune abnormalities, a cogent model has been lacking to link the numerous and seemingly disparate immune aberrations. This may partly explain the general lack of new drugs specifically for SLE in over 50 years. A more coherent model of SLE would not only unify the variety of immune abnormalities is SLE but would also suggest new therapies. Future Directions: The model of augmented homeostatic proliferation leading to increased mitochondrial mass, ROS, DNA demethylation, and upregulation of inflammatory genes suggests strategic new targets for SLE, including antioxidants and certain inhibitors of metabolism. Antioxid. Redox Signal. 36, 410-422.
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Affiliation(s)
- Ralph C Budd
- Department of Medicine, Vermont Center for Immunology and Infectious Diseases, Larner College of Medicine, The University of Vermont, Burlington, Vermont, USA
| | - Christopher D Scharer
- Department of Microbiology and Immunology, School of Medicine, Emory University, Atlanta, Georgia, USA
| | - Ramiro Barrantes-Reynolds
- Department of Microbiology and Molecular Genetics, Larner College of Medicine, The University of Vermont, Burlington, Vermont, USA
| | - Scott Legunn
- Department of Medicine, Vermont Center for Immunology and Infectious Diseases, Larner College of Medicine, The University of Vermont, Burlington, Vermont, USA
| | - Karen A Fortner
- Department of Medicine, Vermont Center for Immunology and Infectious Diseases, Larner College of Medicine, The University of Vermont, Burlington, Vermont, USA
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4
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Guo P, Liu Y, Geng F, Daman AW, Liu X, Zhong L, Ravishankar A, Lis R, Durán JGB, Itkin T, Tang F, Zhang T, Xiang J, Shido K, Ding BS, Wen D, Josefowicz SZ, Rafii S. Histone variant H3.3 maintains adult haematopoietic stem cell homeostasis by enforcing chromatin adaptability. Nat Cell Biol 2022; 24:99-111. [PMID: 34961794 PMCID: PMC9166935 DOI: 10.1038/s41556-021-00795-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 10/14/2021] [Indexed: 01/25/2023]
Abstract
Histone variants and the associated post-translational modifications that govern the stemness of haematopoietic stem cells (HSCs) and differentiation thereof into progenitors (HSPCs) have not been well defined. H3.3 is a replication-independent H3 histone variant in mammalian systems that is enriched at both H3K4me3- and H3K27me3-marked bivalent genes as well as H3K9me3-marked endogenous retroviral repeats. Here we show that H3.3, but not its chaperone Hira, prevents premature HSC exhaustion and differentiation into granulocyte-macrophage progenitors. H3.3-null HSPCs display reduced expression of stemness and lineage-specific genes with a predominant gain of H3K27me3 marks at their promoter regions. Concomitantly, loss of H3.3 leads to a reduction of H3K9me3 marks at endogenous retroviral repeats, opening up binding sites for the interferon regulatory factor family of transcription factors, allowing the survival of rare, persisting H3.3-null HSCs. We propose a model whereby H3.3 maintains adult HSC stemness by safeguarding the delicate interplay between H3K27me3 and H3K9me3 marks, enforcing chromatin adaptability.
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Affiliation(s)
- Peipei Guo
- Department of Medicine, Division of Regenerative Medicine, Ansary Stem Cell Institute, Weill Cornell Medicine, New York, NY, USA. .,Fibrosis Research Center, Mount Sinai-National Jewish Respiratory Institute, Division of Pulmonary, Critical Care and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Ying Liu
- Department of Medicine, Division of Regenerative Medicine, Ansary Stem Cell Institute, Weill Cornell Medicine, New York, NY, USA.,These authors contributed equally: Peipei Guo, Ying Liu
| | - Fuqiang Geng
- Department of Medicine, Division of Regenerative Medicine, Ansary Stem Cell Institute, Weill Cornell Medicine, New York, NY, USA
| | - Andrew W. Daman
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Xiaoyu Liu
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY, USA.,Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Liangwen Zhong
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Arjun Ravishankar
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Raphael Lis
- Department of Medicine, Division of Regenerative Medicine, Ansary Stem Cell Institute, Weill Cornell Medicine, New York, NY, USA.,Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY, USA
| | - José Gabriel Barcia Durán
- Department of Medicine, Division of Regenerative Medicine, Ansary Stem Cell Institute, Weill Cornell Medicine, New York, NY, USA
| | - Tomer Itkin
- Department of Medicine, Division of Regenerative Medicine, Ansary Stem Cell Institute, Weill Cornell Medicine, New York, NY, USA
| | - Fanying Tang
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA.,Weill Cornell Graduate School of Medical Sciences, Weill Cornell Medicine, New York, NY, USA.,Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY, USA
| | - Tuo Zhang
- Weill Cornell Genomics Core Facility, New York, NY, USA
| | - Jenny Xiang
- Weill Cornell Genomics Core Facility, New York, NY, USA
| | - Koji Shido
- Department of Medicine, Division of Regenerative Medicine, Ansary Stem Cell Institute, Weill Cornell Medicine, New York, NY, USA
| | - Bi-sen Ding
- Department of Medicine, Division of Regenerative Medicine, Ansary Stem Cell Institute, Weill Cornell Medicine, New York, NY, USA.,Fibrosis Research Center, Mount Sinai–National Jewish Respiratory Institute, Division of Pulmonary, Critical Care and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Duancheng Wen
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY, USA.
| | - Steven Z. Josefowicz
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Shahin Rafii
- Department of Medicine, Division of Regenerative Medicine, Ansary Stem Cell Institute, Weill Cornell Medicine, New York, NY, USA.
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5
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Young GR, Ferron AKW, Panova V, Eksmond U, Oliver PL, Kassiotis G, Stoye JP. Gv1, a Zinc Finger Gene Controlling Endogenous MLV Expression. Mol Biol Evol 2021; 38:2468-2474. [PMID: 33560369 PMCID: PMC8136514 DOI: 10.1093/molbev/msab039] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The genomes of inbred mice harbor around 50 endogenous murine leukemia virus (MLV) loci, although the specific complement varies greatly between strains. The Gv1 locus is known to control the transcription of endogenous MLVs and to be the dominant determinant of cell-surface presentation of MLV envelope, the GIX antigen. Here, we identify a single Krüppel-associated box zinc finger protein (ZFP) gene, Zfp998, as Gv1 and show it to be necessary and sufficient to determine the GIX+ phenotype. By long-read sequencing of bacterial artificial chromosome clones from 129 mice, the prototypic GIX+ strain, we reveal the source of sufficiency and deficiency as splice-acceptor variations and highlight the varying origins of the chromosomal region encompassing Gv1. Zfp998 becomes the second identified ZFP gene responsible for epigenetic suppression of endogenous MLVs in mice and further highlights the prominent role of this gene family in control of endogenous retroviruses.
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Affiliation(s)
- George R Young
- Retrovirus-host Interactions Laboratory, The Francis Crick Institute, London, UK
| | - Aaron K W Ferron
- Retrovirus-host Interactions Laboratory, The Francis Crick Institute, London, UK
| | - Veera Panova
- Retroviral Immunology, The Francis Crick Institute, London, UK
| | - Urszula Eksmond
- Retroviral Immunology, The Francis Crick Institute, London, UK
| | | | - George Kassiotis
- Retroviral Immunology, The Francis Crick Institute, London, UK.,Department of Infectious Disease, Imperial College London, London, UK
| | - Jonathan P Stoye
- Retrovirus-host Interactions Laboratory, The Francis Crick Institute, London, UK.,Department of Infectious Disease, Imperial College London, London, UK
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6
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Lima-Junior DS, Krishnamurthy SR, Bouladoux N, Collins N, Han SJ, Chen EY, Constantinides MG, Link VM, Lim AI, Enamorado M, Cataisson C, Gil L, Rao I, Farley TK, Koroleva G, Attig J, Yuspa SH, Fischbach MA, Kassiotis G, Belkaid Y. Endogenous retroviruses promote homeostatic and inflammatory responses to the microbiota. Cell 2021; 184:3794-3811.e19. [PMID: 34166614 PMCID: PMC8381240 DOI: 10.1016/j.cell.2021.05.020] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 04/10/2021] [Accepted: 05/14/2021] [Indexed: 02/06/2023]
Abstract
The microbiota plays a fundamental role in regulating host immunity. However, the processes involved in the initiation and regulation of immunity to the microbiota remain largely unknown. Here, we show that the skin microbiota promotes the discrete expression of defined endogenous retroviruses (ERVs). Keratinocyte-intrinsic responses to ERVs depended on cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes protein (STING) signaling and promoted the induction of commensal-specific T cells. Inhibition of ERV reverse transcription significantly impacted these responses, resulting in impaired immunity to the microbiota and its associated tissue repair function. Conversely, a lipid-enriched diet primed the skin for heightened ERV- expression in response to commensal colonization, leading to increased immune responses and tissue inflammation. Together, our results support the idea that the host may have co-opted its endogenous virome as a means to communicate with the exogenous microbiota, resulting in a multi-kingdom dialog that controls both tissue homeostasis and inflammation.
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Affiliation(s)
- Djalma S Lima-Junior
- Metaorganism Immunity Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Siddharth R Krishnamurthy
- Metaorganism Immunity Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; NIAID Microbiome Program, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nicolas Bouladoux
- Metaorganism Immunity Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; NIAID Microbiome Program, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nicholas Collins
- Metaorganism Immunity Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Seong-Ji Han
- Metaorganism Immunity Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Erin Y Chen
- Department of Bioengineering and ChEM-H, Stanford University, Stanford, CA 94305, USA
| | - Michael G Constantinides
- Metaorganism Immunity Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Verena M Link
- Metaorganism Immunity Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; NIH Center for Human Immunology, Bethesda, MD 20896, USA
| | - Ai Ing Lim
- Metaorganism Immunity Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Michel Enamorado
- Metaorganism Immunity Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Christophe Cataisson
- In Vitro Pathogenesis Section, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Louis Gil
- NIAID Microbiome Program, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Indira Rao
- Metaorganism Immunity Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Immunology Graduate Group, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Taylor K Farley
- Metaorganism Immunity Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Roosevelt Drive, Oxford OX3 7FY, UK
| | | | - Jan Attig
- Retroviral Immunology, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Medicine, Faculty of Medicine, Imperial College London, London W2 1PG, UK
| | - Stuart H Yuspa
- In Vitro Pathogenesis Section, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Michael A Fischbach
- Department of Bioengineering and ChEM-H, Stanford University, Stanford, CA 94305, USA
| | - George Kassiotis
- Retroviral Immunology, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Medicine, Faculty of Medicine, Imperial College London, London W2 1PG, UK
| | - Yasmine Belkaid
- Metaorganism Immunity Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; NIAID Microbiome Program, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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7
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Human APOBEC3G Prevents Emergence of Infectious Endogenous Retrovirus in Mice. J Virol 2019; 93:JVI.00728-19. [PMID: 31341050 DOI: 10.1128/jvi.00728-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 07/17/2019] [Indexed: 12/21/2022] Open
Abstract
Endogenous retroviruses (ERV) are found throughout vertebrate genomes, and failure to silence their activation can have deleterious consequences on the host. Mutation and subsequent disruption of ERV loci is therefore an indispensable component of the cell-intrinsic defenses that maintain the integrity of the host genome. Abundant in vitro and in silico evidence have revealed that APOBEC3 cytidine-deaminases, including human APOBEC3G (hA3G), can potently restrict retrotransposition; yet, in vivo data demonstrating such activity is lacking, since no replication-competent human ERV have been identified. In mice deficient for Toll-like receptor 7 (TLR7), transcribed ERV loci can recombine and generate infectious ERV. In this study, we show that ectopic expression of hA3G can prevent the emergence of replication-competent, infectious ERV in Tlr7 -/- mice. Mice encode one copy of Apobec3 in their genome. ERV reactivation in Tlr7 -/- mice was comparable in the presence or absence of Apobec3 In contrast, expression of a human APOBEC3G transgene abrogated emergence of infectious ERV in the Tlr7 -/- background. No ERV RNA was detected in the plasma of hA3G+ Apobec3 -/- Tlr7 -/- mice, and infectious ERV virions could not be amplified through coculture with permissive cells. These data reveal that hA3G can potently restrict active ERV in vivo and suggest that expansion of the APOBEC3 locus in primates may have helped to provide for the continued restraint of ERV in the human genome.IMPORTANCE Although APOBEC3 proteins are known to be important antiviral restriction factors in both mice and humans, their roles in the restriction of endogenous retroviruses (ERV) have been limited to in vitro studies. Here, we report that human APOBEC3G expressed as a transgene in mice prevents the emergence of infectious ERV from endogenous loci. This study reveals that APOBEC3G can powerfully restrict active retrotransposons in vivo and demonstrates how transgenic mice can be used to investigate host mechanisms that inhibit retrotransposons and reinforce genomic integrity.
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8
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Treger RS, Pope SD, Kong Y, Tokuyama M, Taura M, Iwasaki A. The Lupus Susceptibility Locus Sgp3 Encodes the Suppressor of Endogenous Retrovirus Expression SNERV. Immunity 2019; 50:334-347.e9. [PMID: 30709743 DOI: 10.1016/j.immuni.2018.12.022] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/18/2018] [Accepted: 12/17/2018] [Indexed: 12/24/2022]
Abstract
Elevated endogenous retrovirus (ERV) transcription and anti-ERV antibody reactivity are implicated in lupus pathogenesis. Overproduction of non-ecotropic ERV (NEERV) envelope glycoprotein gp70 and resultant nephritis occur in lupus-prone mice, but whether NEERV mis-expression contributes to lupus etiology is unclear. Here we identified suppressor of NEERV (Snerv) 1 and 2, Krüppel-associated box zinc-finger proteins (KRAB-ZFPs) that repressed NEERV by binding the NEERV long terminal repeat to recruit the transcriptional regulator KAP1. Germline Snerv1/Snerv2 deletion increased activating chromatin modifications, transcription, and gp70 expression from NEERV loci. F1 crosses of lupus-prone New Zealand Black (NZB) and 129 mice to Snerv1/Snerv2-/- mice failed to restore NEERV repression, demonstrating that loss of SNERV underlies the lupus autoantigen gp70 overproduction that promotes nephritis in susceptible mice and that SNERV encodes for Sgp3 (in NZB mice) and Gv-1 loci (in 129 mice). Increased ERV expression in lupus patients inversely correlated with three putative ERV-suppressing KRAB-ZFPs, suggesting that loss of KRAB-ZFP-mediated ERV control may contribute to human lupus pathogenesis.
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Affiliation(s)
- Rebecca S Treger
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Scott D Pope
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Yong Kong
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Molecular Biophysics and Biochemistry, W.M. Keck Foundation Biotechnology Resource Laboratory, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Maria Tokuyama
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Manabu Taura
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Akiko Iwasaki
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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9
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Stoltz KP, Jondle CN, Pulakanti K, Sylvester PA, Urrutia R, Rao S, Tarakanova VL. Tumor suppressor Interferon Regulatory Factor 1 selectively blocks expression of endogenous retrovirus. Virology 2019; 526:52-60. [PMID: 30342302 PMCID: PMC6875439 DOI: 10.1016/j.virol.2018.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/01/2018] [Accepted: 10/01/2018] [Indexed: 01/23/2023]
Abstract
Endogenous retroviruses (ERVs) comprise 10% of the genome, with many of these transcriptionally silenced post early embryogenesis. Several stimuli, including exogenous virus infection and cellular transformation can reactivate ERV expression via a poorly understood mechanism. We identified Interferon Regulatory Factor 1 (IRF-1), a tumor suppressor and an antiviral host factor, as a suppressor of ERV expression. IRF-1 decreased expression of a specific mouse ERV in vitro and in vivo. IRF-3, but not IRF-7, also decreased expression of distinct ERV families, suggesting that suppression of ERVs is a relevant biological function of the IRF family. Given the emerging appreciation of the physiological relevance of ERV expression in cancer, IRF-1-mediated suppression of specific ERVs may contribute to the overall tumor suppressor activity of this host factor.
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Affiliation(s)
- K P Stoltz
- Microbiology and Immunology Department, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - C N Jondle
- Microbiology and Immunology Department, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - K Pulakanti
- Blood Research Institute, BloodCenter of Wisconsin, a Part of Versiti, 8727 West Watertown Plank Road, Milwaukee, WI 53226, United States
| | - P A Sylvester
- Microbiology and Immunology Department, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - R Urrutia
- Cancer Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States; Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - S Rao
- Blood Research Institute, BloodCenter of Wisconsin, a Part of Versiti, 8727 West Watertown Plank Road, Milwaukee, WI 53226, United States.
| | - V L Tarakanova
- Microbiology and Immunology Department, Medical College of Wisconsin, Milwaukee, Wisconsin, United States; Cancer Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States.
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10
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Darrah EJ, Stoltz KP, Ledwith M, Tarakanova VL. ATM supports gammaherpesvirus replication by attenuating type I interferon pathway. Virology 2017; 510:137-146. [PMID: 28732227 DOI: 10.1016/j.virol.2017.07.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/21/2017] [Accepted: 07/10/2017] [Indexed: 12/17/2022]
Abstract
Ataxia-Telangiectasia mutated (ATM) kinase participates in multiple networks, including DNA damage response, oxidative stress, and mitophagy. ATM also supports replication of diverse DNA and RNA viruses. Gammaherpesviruses are prevalent cancer-associated viruses that benefit from ATM expression during replication. This proviral role of ATM had been ascribed to its signaling within the DNA damage response network; other functions of ATM have not been considered. In this study increased type I interferon (IFN) responses were observed in ATM deficient gammaherpesvirus-infected macrophages. Using a mouse model that combines ATM and type I IFN receptor deficiencies we show that increased type I IFN response in the absence of ATM fully accounts for the proviral role of ATM during gammaherpesvirus replication. Further, increased type I IFN response rendered ATM deficient macrophages more susceptible to antiviral effects of type II IFN. This study identifies attenuation of type I IFN responses as the primary mechanism underlying proviral function of ATM during gammaherpesvirus infection.
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Affiliation(s)
- Eric J Darrah
- Department of Microbiology and Immunology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, United States
| | - Kyle P Stoltz
- Department of Microbiology and Immunology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, United States
| | - Mitchell Ledwith
- Department of Microbiology and Immunology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, United States
| | - Vera L Tarakanova
- Department of Microbiology and Immunology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, United States; Cancer Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, United States.
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11
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Boi S, Rosenke K, Hansen E, Hendrick D, Malik F, Evans LH. Endogenous retroviruses mobilized during friend murine leukemia virus infection. Virology 2016; 499:136-143. [PMID: 27657834 DOI: 10.1016/j.virol.2016.07.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 07/05/2016] [Accepted: 07/06/2016] [Indexed: 10/21/2022]
Abstract
We have demonstrated in a mouse model that infection with a retrovirus can lead not only to the generation of recombinants between exogenous and endogenous gammaretrovirus, but also to the mobilization of endogenous proviruses by pseudotyping entire polytropic proviral transcripts and facilitating their infectious spread to new cells. However, the frequency of this occurrence, the kinetics, and the identity of mobilized endogenous proviruses was unclear. Here we find that these mobilized transcripts are detected after only one day of infection. They predominate over recombinant polytropic viruses early in infection, persist throughout the course of disease and are comprised of multiple different polytropic proviruses. Other endogenous retroviral elements such as intracisternal A particles (IAPs) were not detected. The integration of the endogenous transcripts into new cells could result in loss of transcriptional control and elevated expression which may facilitate pathogenesis, perhaps by contributing to the generation of polytropic recombinant viruses.
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Affiliation(s)
- Stefano Boi
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840
| | - Kyle Rosenke
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840
| | - Ethan Hansen
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840
| | - Duncan Hendrick
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840
| | - Frank Malik
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840
| | - Leonard H Evans
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840
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12
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McDonald G, Cabal N, Vannier A, Umiker B, Yin RH, Orjalo AV, Johansson HE, Han JH, Imanishi-Kari T. Female Bias in Systemic Lupus Erythematosus is Associated with the Differential Expression of X-Linked Toll-Like Receptor 8. Front Immunol 2015; 6:457. [PMID: 26441962 PMCID: PMC4561825 DOI: 10.3389/fimmu.2015.00457] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 08/24/2015] [Indexed: 11/28/2022] Open
Abstract
Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of anti-nuclear antibodies. SLE is one of many autoimmune disorders that have a strong gender bias, with 70–90% of SLE patients being female. Several explanations have been postulated to account for the severity of autoimmune diseases in females, including hormonal, microbiota, and gene dosage differences. X-linked toll-like receptors (TLRs) have recently been implicated in disease progression in females. Our previous studies using the 564Igi mouse model of SLE on a Tlr7 and Tlr9 double knockout background showed that the presence of Tlr8 on both X chromosomes was required for the production of IgG autoantibodies, Ifn-I expression and granulopoiesis in females. Here, we show the results of our investigation into the role of Tlr8 expression in SLE pathogenesis in 564Igi females. Female mice have an increase in serum pathogenic anti-RNA IgG2a and IgG2b autoantibodies. 564Igi mice have also been shown to have an increase in neutrophils in vivo, which are major contributors to Ifn-α expression. Here, we show that neutrophils from C57BL/6 mice express Ifn-α in response to 564 immune complexes and TLR8 activation. Bone marrow-derived macrophages from 564Igi females have a significant increase in Tlr8 expression compared to male-derived cells, and RNA fluorescence in situ hybridization data suggest that Tlr8 may escape X-inactivation in female-derived macrophages. These results propose a model by which females may be more susceptible to SLE pathogenesis due to inefficient inactivation of Tlr8.
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Affiliation(s)
- Gabrielle McDonald
- Department of Integrative Physiology and Pathobiology, Tufts University , Boston, MA , USA
| | - Nicholas Cabal
- Department of Integrative Physiology and Pathobiology, Tufts University , Boston, MA , USA
| | - Augustin Vannier
- Department of Integrative Physiology and Pathobiology, Tufts University , Boston, MA , USA
| | - Benjamin Umiker
- Department of Integrative Physiology and Pathobiology, Tufts University , Boston, MA , USA
| | | | | | | | - Jin-Hwan Han
- Merck Research Laboratories , Palo Alto, CA , USA
| | - Thereza Imanishi-Kari
- Department of Integrative Physiology and Pathobiology, Tufts University , Boston, MA , USA
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13
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Hurst TP, Magiorkinis G. Activation of the innate immune response by endogenous retroviruses. J Gen Virol 2015; 96:1207-1218. [PMID: 26068187 DOI: 10.1099/jgv.0.000017] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The human genome comprises 8 % endogenous retroviruses (ERVs), the majority of which are defective due to deleterious mutations. Nonetheless, transcripts of ERVs are found in most tissues, and these transcripts could either be reverse transcribed to generate ssDNA or expressed to generate proteins. Thus, the expression of ERVs could produce nucleic acids or proteins with viral signatures, much like the pathogen-associated molecular patterns of exogenous viruses, which would enable them to be detected by the innate immune system. The activation of some pattern recognition receptors (PRRs) in response to ERVs has been described in mice and in the context of human autoimmune diseases. Here, we review the evidence for detection of ERVs by PRRs and the resultant activation of innate immune signalling. This is an emerging area of research within the field of innate antiviral immunity, showing how ERVs could initiate immune signalling pathways and might have implications for numerous inflammatory diseases.
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Affiliation(s)
- Tara P Hurst
- Department of Zoology, University of Oxford, Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
| | - Gkikas Magiorkinis
- Department of Zoology, University of Oxford, Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
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14
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Tran NL, Manzin-Lorenzi C, Santiago-Raber ML. Toll-like receptor 8 deletion accelerates autoimmunity in a mouse model of lupus through a Toll-like receptor 7-dependent mechanism. Immunology 2015; 145:60-70. [PMID: 25424423 DOI: 10.1111/imm.12426] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 11/13/2014] [Accepted: 11/21/2014] [Indexed: 12/22/2022] Open
Abstract
Systemic lupus erythematosus is an autoimmune disorder characterized by increased levels of lymphocyte activation, antigen presentation by dendritic cells, and the formation of autoantibodies. This leads to immune complex-mediated glomerulonephritis. Toll-like receptor 7 (T7) and TLR9 localize to the endosomal compartment and play important roles in the generation of autoantibodies against nuclear components, as they recognize RNA and DNA, respectively. In contrast, very little is known about endogenous TLR8 activation in mice. We therefore tested whether TLR8 could affect autoimmune responses in a murine model of lupus. We introduced a Tlr8 null mutation into C57BL/6 mice congenic for the Nba2 (NZB autoimmunity 2) locus and bearing the Yaa (Y-linked autoimmune acceleration) mutation containing a tlr8 duplicated gene, and monitored disease development, autoantibody production, and glomerulonephritis-associated mortality. Cellular responses were investigated in female Nba2.TLR8(-/-) mice bearing no copy of tlr8. The TLR8 deficiency accelerated disease progression and mortality, increased the number of circulating antibodies and activated monocytes, and heightened cellular responses to TLR7 ligation. TLR8-deficient antigen-presenting cells exhibited increased levels of MHC class II expression. The ability of dendritic cells to present antigens to allogeneic T cells after TLR7 ligation was also improved by TLR8 deficiency. TLR8 deletion accelerated autoimmunity in lupus-prone mice in response to TLR7 activation. Antigen-presenting cell function seemed to play a key role in mediating the effects of TLR8 deficiency.
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Affiliation(s)
- Ngoc Lan Tran
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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15
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16
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Thorborn G, Young GR, Kassiotis G. Effective T helper cell responses against retroviruses: are all clonotypes equal? J Leukoc Biol 2014; 96:27-37. [PMID: 24737804 DOI: 10.1189/jlb.2ri0613-347r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The critical importance of CD4(+) T cells in coordinating innate and adaptive immune responses is evidenced by the susceptibility to various pathogenic and opportunistic infections that arises from primary or acquired CD4(+) T cell immunodeficiency, such as following HIV-1 infection. However, despite the clearly defined roles of cytotoxic CD8(+) T cells and antibodies in host protection from retroviruses, the ability of CD4(+) T cells to exert a similar function remains unclear. Recent studies in various settings have drawn attention to the complexity of the T cell response within and between individuals. Distinct TCR clonotypes within an individual differ substantially in their response to the same epitope. Functionally similar, "public" TCR clonotypes can also dominate the response of different individuals. TCR affinity for antigen directly influences expansion and differentiation of responding T cells, also likely affecting their ultimate protective capacity. With this increasing understanding of the parameters that determine the magnitude and effector type of the T cell response, we are now better equipped to address the protective capacity against retroviruses of CD4(+) T cell clonotypes induced by natural infection or vaccination.
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Affiliation(s)
| | - George R Young
- Divisions of Immunoregulation and Virology, Medical Research Council National Institute for Medical Research, The Ridgeway, London, United Kingdom; and
| | - George Kassiotis
- Divisions of Immunoregulation and Department of Medicine, Faculty of Medicine, Imperial College London, United Kingdom
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17
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Kono DH, Baccala R, Theofilopoulos AN. TLRs and interferons: a central paradigm in autoimmunity. Curr Opin Immunol 2013; 25:720-7. [PMID: 24246388 DOI: 10.1016/j.coi.2013.10.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/06/2013] [Indexed: 01/08/2023]
Abstract
Investigations into the pathogenesis of lupus have largely focused on abnormalities in components of the adaptive immune system. Despite important advances, however, the question about the origin of the pathogenic process, the primary disease trigger, and the dominance of autoantibodies against nuclear components, remained unanswered. Discoveries in the last decade have provided some resolution to these questions by elucidating the central role of nucleic acid-sensing TLRs and the attendant inflammatory response, particularly the production of type I interferons. These priming events are responsible for initiating the adaptive responses that ultimately mediate the pathogenic process.
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Affiliation(s)
- Dwight H Kono
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, United States.
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18
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Koh YT, Scatizzi JC, Gahan JD, Lawson BR, Baccala R, Pollard KM, Beutler BA, Theofilopoulos AN, Kono DH. Role of nucleic acid-sensing TLRs in diverse autoantibody specificities and anti-nuclear antibody-producing B cells. THE JOURNAL OF IMMUNOLOGY 2013; 190:4982-90. [PMID: 23589617 DOI: 10.4049/jimmunol.1202986] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Nucleic acid (NA)-sensing TLRs (NA-TLRs) promote the induction of anti-nuclear Abs in systemic lupus erythematosus. However, the extent to which other nonnuclear pathogenic autoantibody specificities that occur in lupus and independently in other autoimmune diseases depend on NA-TLRs, and which immune cells require NA-TLRs in systemic autoimmunity, remains to be determined. Using Unc93b1(3d) lupus-prone mice that lack NA-TLR signaling, we found that all pathogenic nonnuclear autoantibody specificities examined, even anti-RBC, required NA-TLRs. Furthermore, we document that NA-TLRs in B cells were required for the development of antichromatin and rheumatoid factor. These findings support a unifying NA-TLR-mediated mechanism of autoantibody production that has both pathophysiological and therapeutic implications for systemic lupus erythematosus and several other humoral-mediated autoimmune diseases. In particular, our findings suggest that targeting of NA-TLR signaling in B cells alone would be sufficient to specifically block production of a broad diversity of autoantibodies.
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Affiliation(s)
- Yi Ting Koh
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA
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19
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Ito K, Baudino L, Kihara M, Leroy V, Vyse TJ, Evans LH, Izui S. Three Sgp loci act independently as well as synergistically to elevate the expression of specific endogenous retroviruses implicated in murine lupus. J Autoimmun 2013; 43:10-7. [PMID: 23465716 DOI: 10.1016/j.jaut.2013.01.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 01/28/2013] [Accepted: 01/31/2013] [Indexed: 01/06/2023]
Abstract
Endogenous retroviruses are implicated in murine lupus nephritis. They provide a source of nephritogenic retroviral gp70-anti-gp70 immune complexes through the production of serum gp70 protein and anti-gp70 autoantibodies as a result of the activation of TLR7. The Sgp (serum gp70 production) loci identified in lupus-prone mice play distinct roles for the expression of different classes of endogenous retroviruses, as Sgp3 regulates the transcription of xenotropic, polytropic and modified polytropic (mPT) viruses, and Sgp4 the transcription of only xenotropic viruses. In the present study, we extended these analyses to a third locus, Sgp5, using BALB/c mice congenic for the NZW-derived Sgp5 allele and also explored the possible interaction of Sgp3 and Sgp4 loci to promote the expression of endogenous retroviruses and serum gp70. The analysis of Sgp5 BALB/c congenic mice demonstrated that the Sgp5 locus enhanced the expression of xenotropic and mPT viruses, thereby upregulating the production of serum gp70. These data indicate a distinct action of the Sgp5 locus on the expression of endogenous retroviruses, as compared with two other Sgp loci. Moreover, comparative analysis of C57BL/6 double congenic mice for Sgp3 and Sgp4 loci with single congenic mice revealed that Sgp3 and Sgp4 acted synergistically to elevate the transcription of the potentially replication-competent Xmv18 provirus and the production of serum gp70. This indicates that the combined effect of three different Sgp loci markedly enhance the expression of endogenous retroviruses and their gene product, serum gp70, thereby contributing to the formation of nephritogenic gp70-anti-gp70 immune complexes in murine lupus.
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Affiliation(s)
- Kiyoaki Ito
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva 4, Switzerland
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20
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Pau E, Loh C, Minty GES, Chang NH, Wither JE. Identification of a lupus-susceptibility locus leading to impaired clearance of apoptotic debris on New Zealand Black chromosome 13. Genes Immun 2013; 14:154-61. [PMID: 23328841 PMCID: PMC4931923 DOI: 10.1038/gene.2012.64] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Systemic lupus erythematosus is a chronic multi-organ autoimmune disease marked mainly by the production of anti-nuclear antibodies. Nuclear antigens become accessible to the immune system following apoptosis and defective clearance of apoptotic debris has been shown in several knockout mouse models to promote lupus. However, genetic loci associated with defective clearance are not well defined in spontaneously arising lupus models. We previously showed that introgression of the chromosome 13 interval from lupus-prone New Zealand Black (NZB) mice onto a non-autoimmune B6 genetic background (B6.NZBc13) recapitulated many of the NZB autoimmune phenotypes. Here, we show that B6.NZBc13 mice have impaired clearance of apoptotic debris by peritoneal and tingible-body macrophages and have narrowed down the chromosomal interval of this defect using subcongenic mice with truncated NZB chromosome 13 intervals. This chromosomal region (81-94 Mb) is sufficient to produce polyclonal B- and T-cell activation, and expansion of dendritic cells. To fully recapitulate the autoimmune phenotypes seen in B6.NZBc13 mice, at least one additional locus located in the centromeric portion of the interval is required. Thus, we have identified a novel lupus susceptibility locus on NZB chromosome 13 that is associated with impaired clearance of apoptotic debris.
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Affiliation(s)
- E Pau
- Arthritis Centre of Excellence, Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
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21
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Young GR, Eksmond U, Salcedo R, Alexopoulou L, Stoye JP, Kassiotis G. Resurrection of endogenous retroviruses in antibody-deficient mice. Nature 2012; 491:774-8. [PMID: 23103862 PMCID: PMC3511586 DOI: 10.1038/nature11599] [Citation(s) in RCA: 169] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 09/18/2012] [Indexed: 01/12/2023]
Abstract
The mammalian host has developed a long-standing symbiotic relationship with a considerable number of microbial species. These include the microbiota on environmental surfaces, such as the respiratory and gastrointestinal tracks1, and also endogenous retroviruses (ERVs), comprising a substantial fraction of the mammalian genome2,3. The long-term consequences for the host of interaction with these microbial species can range from mutualism to parasitism and are not always completely understood. The potential impact of one microbial symbiont on another is even less clear. We have studied the control of ERVs in the commonly-used C57BL/6 (B6) mouse strain, which lacks endogenous murine leukaemia viruses (MLVs) able to replicate in murine cells. We demonstrate the spontaneous emergence of fully infectious ecotropic4 MLV (eMLV) in B6 mice with a range of distinct immune deficiencies affecting antibody production. These recombinant retroviruses establish infection of immunodeficient mouse colonies, and ultimately result in retrovirus-induced lymphomas. Notably, ERV activation in immune-deficient mice is prevented in husbandry conditions associated with reduced or absent intestinal microbiota. Our results shed light onto a previously unappreciated role for immunity in the control of ERVs and provide a potential mechanistic link between immune activation by microbial triggers and a range of pathologies associated with ERVs, including cancer.
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Affiliation(s)
- George R Young
- Division of Immunoregulation, MRC National Institute for Medical Research, The Ridgeway, London NW7 1AA, UK
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22
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Leroy V, Kihara M, Baudino L, Brighouse G, Evans LH, Izui S. Sgp3 and TLR7 stimulation differentially alter the expression profile of modified polytropic retroviruses implicated in murine systemic lupus. J Autoimmun 2012; 38:361-8. [PMID: 22503566 DOI: 10.1016/j.jaut.2012.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 02/27/2012] [Accepted: 03/07/2012] [Indexed: 12/24/2022]
Abstract
The envelope glycoprotein, gp70, of endogenous retroviruses represents one of the major nephritogenic autoantigens implicated in murine systemic lupus erythematosus. Among different endogenous retroviruses (ecotropic, xenotropic and polytropic), lupus-prone mice express remarkably high levels of modified polytropic (mPT) retroviruses, which are controlled by the Sgp3 (serum gp70 production) locus. To define the contribution of the Sgp3 locus derived from lupus-prone mice to the expression of the specific mPT proviruses, the genetic origin of different mPT viruses expressed in livers and thymi of wild-type and Sgp3 congenic C57BL/6 mice was determined through clonal analysis of their transcripts. Among 13 mPT proviruses present in the C57BL/6 genome, only 3 proviruses (Mpmv6, Mpmv10 and Mpmv13) were selectively but differentially expressed in livers and thymi. This was likely a result of co-regulated expression with host genes because of their integration in the same transcriptional direction. In contrast, Sgp3 induced the steady-state expression of an additional select group of mPT proviruses and, after stimulation of TLR7, the highly upregulated expression of a potentially replication-competent mPT virus Mpmv4. These results indicated that the expression of distinct subpopulations of mPT retroviruses was regulated by Sgp3- and TLR7-dependent mechanisms. The induction of potentially replication-competent mPT viruses and the upregulation of one such virus after stimulation with TLR7 in Sgp3 congenic mice further highlight the implication of Sgp3 in autoimmune responses against nephritogenic serum gp70 through the activation of TLR7.
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Affiliation(s)
- Valérie Leroy
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva 4, Switzerland
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23
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Kihara M, Leroy V, Baudino L, Evans LH, Izui S. Sgp3 and Sgp4 control expression of distinct and restricted sets of xenotropic retroviruses encoding serum gp70 implicated in murine lupus nephritis. J Autoimmun 2011; 37:311-8. [PMID: 21982749 DOI: 10.1016/j.jaut.2011.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 09/02/2011] [Accepted: 09/05/2011] [Indexed: 12/23/2022]
Abstract
The envelope glycoprotein gp70 of endogenous retroviruses implicated in murine lupus nephritis is secreted by hepatocytes and its expression is controlled by Sgp3 (serum gp70 production 3) and Sgp4 loci derived from lupus-prone mice. Among three different endogenous retroviruses (ecotropic, xenotropic and polytropic), xenotropic viruses are considered to be the major source of serum gp70. Although the abundance of xenotropic viral gp70 RNA in livers was up-regulated by the presence of these two Sgp loci, it has not yet been clear whether Sgp3 and Sgp4 regulate the expression of a fraction or multiple xenotropic viruses present in mouse genome. To address this question, we determined the genetic origin of xenotropic viral sequences expressed in wild-type and two different Sgp congenic C57BL/6 mice. Among 14 xenotropic proviruses present in the C57BL/6 genome, only two proviruses (Xmv10 and Xmv14) were actively transcribed in wild-type C57BL/6 mice. In contrast, Sgp3 enhanced the transcription of Xmv10 and induced the transcription of three additional xenotropic viruses (Xmv15, Xmv17 and Xmv18), while Sgp4 induced the expression of a different xenotropic virus (Xmv13). Notably, stimulation of TLR7 in Sgp3 congenic C57BL/6 mice led to a highly enhanced expression of potentially replication-competent Xmv18. These results indicated that Sgp3 and Sgp4 independently regulated the transcription of distinct and restricted sets of xenotropic viruses in trans, thereby promoting the production of nephritogenic gp70 autoantigens. Furthermore, the induced expression of potentially replication-competent xenotropic viruses by Sgp3 may contribute to the development of autoimmune responses against gp70 through the activation of TLR7.
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Affiliation(s)
- Masao Kihara
- Department of Pathology and Immunology, University of Geneva, 1211 Geneve 4, Switzerland
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24
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Pásztói M, Misják P, György B, Aradi B, Szabó TG, Szántó B, Holub MC, Nagy G, Falus A, Buzás EI. Infection and autoimmunity: Lessons of animal models. Eur J Microbiol Immunol (Bp) 2011; 1:198-207. [PMID: 24516725 DOI: 10.1556/eujmi.1.2011.3.3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 07/11/2011] [Indexed: 12/25/2022] Open
Abstract
While the key initiating processes that trigger human autoimmune diseases remain enigmatic, increasing evidences support the concept that microbial stimuli are among major environmental factors eliciting autoimmune diseases in genetically susceptible individuals. Here, we present an overview of evidences obtained through various experimental models of autoimmunity for the role of microbial stimuli in disease development. Disease onset and severity have been compared in numerous models under conventional, specific-pathogen-free and germ-free conditions. The results of these experiments suggest that there is no uniform scheme that could describe the role played by infectious agents in the experimental models of autoimmunity. While some models are dependent, others prove to be completely independent of microbial stimuli. In line with the threshold hypothesis of autoimmune diseases, highly relevant genetic factors or microbial stimuli induce autoimmunity on their own, without requiring further factors. Importantly, recent evidences show that colonization of germ-free animals with certain members of the commensal flora [such as segmented filamentous bacteria (SFB)] may lead to autoimmunity. These data drive attention to the importance of the complex composition of gut flora in maintaining immune homeostasis. The intriguing observation obtained in autoimmune animal models that parasites often confer protection against autoimmune disease development may suggest new therapeutic perspectives of infectious agents in autoimmunity.
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25
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Loh C, Pau E, Chang NH, Wither JE. An intrinsic B-cell defect supports autoimmunity in New Zealand black chromosome 13 congenic mice. Eur J Immunol 2010; 41:527-36. [PMID: 21268021 DOI: 10.1002/eji.201040983] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 10/25/2010] [Accepted: 11/23/2010] [Indexed: 11/06/2022]
Abstract
Introgression of a New Zealand Black (NZB) chromosome 13 interval onto a C57BL/6 (B6) background (B6.NZBc13) is sufficient to produce many hallmarks of lupus, including high-titre anti-chromatin antibody production, abnormal B- and T-cell activation, and renal disease. In this study we sought to characterize the immune defects leading to these abnormalities. By generating hematopoietic chimeras and BCR transgenic mice, we show that the congenic autoimmune phenotype can be transferred by BM cells and requires the presence of autoreactive B cells. Using the hen egg white lysozyme immunoglobulin transgenic mouse model, we demonstrate that B-cell anergy, deletion, and receptor editing are intact. Nevertheless, congenic B cells exhibit altered peripheral B-cell selection, as demonstrated by enhanced survival and activation of endogenous B cells with autoreactivity to chromatin and Sm/ribonucleoprotein. Given the autoantibody specificities to nuclear antigens, TLR signalling was assessed. B6.NZBc13 B cells were hyper-responsive to poly(I:C), a TLR3 ligand, demonstrating enhanced proliferation and survival as compared to B6 B cells. Our findings indicate the presence of an intrinsic B-cell defect on NZB chromosome 13 that results in hyper-responsiveness to a dsRNA analogue and implicates its potential supporting role in the generation of autoimmunity in B6.NZBc13 mice.
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Affiliation(s)
- Christina Loh
- Arthritis Centre of Excellence, Toronto Western Research Institute, Toronto, ON, Canada
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Baudino L, Changolkar LN, Pehrson JR, Izui S. The Sgp3 locus derived from the 129 strain is responsible for enhanced endogenous retroviral expression in macroH2A1-deficient mice. J Autoimmun 2010; 35:398-403. [PMID: 20833509 DOI: 10.1016/j.jaut.2010.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 08/17/2010] [Accepted: 08/22/2010] [Indexed: 10/19/2022]
Abstract
The endogenous retroviral envelope glycoprotein, gp70, implicated in murine lupus nephritis is secreted by hepatocytes, and its expression is largely regulated by the Sgp3 (serum gp70 production 3) locus derived from lupus-prone mice. Because of the localization of the macroH2A1 gene encoding macroH2A histone variants within the Sgp3 interval and of an up-regulated transcription of endogenous retroviral sequences in macroH2A1-deficient C57BL/6 (B6) mice, we investigated whether macroH2A1 is a candidate gene for Sgp3. macroH2A1-deficient B6 mice carrying the 129-derived Sgp3 locus, which was co-transferred with the 129 macroH2A1 mutant gene, displayed increased levels of serum gp70 and hepatic retroviral gp70 RNAs comparable to those of B6.NZB-Sgp3 congenic mice bearing the Sgp3 locus of lupus-prone NZB mice. In contrast, the abundance of retroviral gp70 RNAs in macroH2A1-deficient 129 mice was not elevated at all as compared with wild-type 129 mice. Furthermore, Sgp3 subcongenic B6 mice devoid of the NZB-derived macroH2A1 gene displayed an Sgp3 phenotype identical to that of B6.NZB-Sgp3 congenic mice carrying the NZB-derived macroH2A1 gene, thus excluding macroH2A1 as a candidate Sgp3 gene. Collectively, our data indicate that enhanced transcription of endogenous retroviral sequences observed in macroH2A1-deficient B6 mice is not a result of the macroH2A1 mutation, but due to the presence of the 129-derived Sgp3 locus. In contrast, the effect of a macroH2A1 knockout mutation on the expression of several non-retroviral cellular genes was very similar on the B6 and 129 backgrounds, indicating that these effects were due to the macroH2A1 knockout.
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Affiliation(s)
- Lucie Baudino
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva 4, Switzerland
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Abstract
PURPOSE OF REVIEW Genetic and environmental factors influence the development of systemic lupus erythematosus (SLE). Endogenous retroviruses (ERVs) are proposed as a molecular link between the human genome and environmental factors, such as viruses, in lupus pathogenesis. RECENT FINDINGS The HRES-1 human ERV encodes a 28-kD nuclear autoantigen and a 24-kD small GTP-ase, termed HRES-1/Rab4. HRES-1/p28 is a target of cross-reactive antiviral antibodies, whereas HRES-1/Rab4 regulates the surface expression of CD4 via endosome recycling. The tat gene of HIV-1 induces the expression of HRES-1/Rab4, which in turn downregulates expression of CD4 and susceptibility to reinfection by HIV-1. HRES-1/Rab4 is overexpressed in lupus T cells where it correlates with increased recycling of CD4 and CD3 and contributes to downregulation of CD3/TCRzeta via lysosomal degradation. Chilblain lupus has been linked to the deficiency of 3'-5' repair exonuclease Trex1 that metabolizes DNA reverse-transcribed from ERV. Trex1 deficiency or blocked integration of ERV-encoded DNA also promotes lupus in murine models. SUMMARY ERV proteins may trigger lupus through structural and functional molecular mimicry, whereas the accumulation of ERV-derived nucleic acids stimulates interferon and anti-DNA antibody production in SLE.
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Affiliation(s)
- Andras Perl
- Division of Rheumatology, Department of Medicine and Microbiology and Immunology, State University of New York Upstate Medical University, Syracuse, New York, USA.
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Baudino L, Yoshinobu K, Morito N, Santiago-Raber ML, Izui S. Role of endogenous retroviruses in murine SLE. Autoimmun Rev 2010; 10:27-34. [PMID: 20659589 DOI: 10.1016/j.autrev.2010.07.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 07/21/2010] [Indexed: 11/17/2022]
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by B cell hyperactivity leading to the production of various autoantibodies and subsequent development of glomerulonephritis, i.e. lupus nephritis. Among the principal targets of the autoantibodies produced in murine SLE are nucleic acid-protein complexes and the envelope glycoprotein gp70 of endogenous retroviruses. Recent studies have revealed that the innate receptor TLR7 plays a pivotal role in the development of a wide variety of autoimmune responses against DNA- and RNA-containing nuclear antigens, while TLR9 rather plays a protective role. In addition, the regulation of autoimmune responses against endogenous retroviral gp70 by TLR7 suggests the implication of endogenous retroviruses in this autoimmune response. Moreover, the demonstration that TLR7 is involved in the acute phase expression of serum gp70 uncovers an additional pathogenic role of TLR7 in murine lupus nephritis by promoting the expression of nephritogenic gp70 autoantigen. Clearly, the eventual identification of endogenous retroviruses implicated in murine SLE and of mouse genes regulating their production could provide a clue for the potential role of endogenous retroviruses in human SLE.
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Affiliation(s)
- Lucie Baudino
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
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Baudino L, Yoshinobu K, Dunand-Sauthier I, Evans LH, Izui S. TLR-mediated up-regulation of serum retroviral gp70 is controlled by the Sgp loci of lupus-prone mice. J Autoimmun 2010; 35:153-9. [PMID: 20619604 DOI: 10.1016/j.jaut.2010.06.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 06/08/2010] [Accepted: 06/13/2010] [Indexed: 12/29/2022]
Abstract
The endogenous retroviral envelope glycoprotein, gp70, implicated in murine systemic lupus erythematosus (SLE), has been considered to be a product of xenotropic, polytropic (PT) and modified PT (mPT) endogenous retroviruses. It is secreted by hepatocytes like an acute phase protein, but its response is under a genetic control. Given critical roles of TLR7 and TLR9 in the pathogenesis of SLE, we assessed their contribution to the acute phase expression of serum gp70, and defined a pivotal role of the Sgp3 (serum gp70 production 3) and Sgp4 loci in this response. Our results demonstrated that serum levels of gp70 were up-regulated in lupus-prone NZB mice injected with TLR7 or TLR9 agonist at levels comparable to those induced by injection of IL-1, IL-6 or TNF. In addition, studies of C57BL/6 Sgp3 and/or Sgp4 congenic mice defined the major roles of these two loci in up-regulated production of serum gp70 during acute phase responses. Finally, the analysis of Sgp3 congenic mice strongly suggests the presence of at least two distinct genetic factors in the Sgp3 interval, one of which controlled the basal-level expression of xenotropic, PT and mPT gp70 and the other which controlled the up-regulated production of xenotropic and mPT gp70 during acute phase responses. Our results uncovered an additional pathogenic role of TLR7 and TLR9 in murine lupus nephritis by promoting the expression of nephritogenic gp70 autoantigen. Furthermore, they revealed the involvement of multiple regulatory genes for the expression of gp70 autoantigen under steady-state and inflammatory conditions in lupus-prone mice.
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Affiliation(s)
- Lucie Baudino
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
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Santiago-Raber ML, Dunand-Sauthier I, Wu T, Li QZ, Uematsu S, Akira S, Reith W, Mohan C, Kotzin BL, Izui S. Critical role of TLR7 in the acceleration of systemic lupus erythematosus in TLR9-deficient mice. J Autoimmun 2010; 34:339-48. [DOI: 10.1016/j.jaut.2009.11.001] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 11/03/2009] [Accepted: 11/04/2009] [Indexed: 10/20/2022]
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Abstract
Systemic lupus erythematosus (SLE) is a chronic inflammatory disease characterized by the dysfunction of T cells, B cells, and dendritic cells and by the production of antinuclear autoantibodies. This editorial provides a synopsis of newly discovered genetic factors and signaling pathways in lupus pathogenesis that are documented in 11 state-of-the-art reviews and original articles. Mitochondrial hyperpolarization underlies mitochondrial dysfunction, depletion of ATP, oxidative stress, abnormal activation, and death signal processing in lupus T cells. The mammalian target of rapamycin, which is a sensor of the mitochondrial transmembrane potential, has been successfully targeted for treatment of SLE with rapamycin or sirolimus in both patients and animal models. Inhibition of oxidative stress, nitric oxide production, expression of endogenous retroviral and repetitive elements such as HRES-1, the long interspersed nuclear elements 1, Trex1, interferon alpha (IFN-alpha), toll-like receptors 7 and 9 (TLR-7/9), high-mobility group B1 protein, extracellular signal-regulated kinase, DNA methyl transferase 1, histone deacetylase, spleen tyrosine kinase, proteasome function, lysosome function, endosome recycling, actin cytoskeleton formation, the nuclear factor kappa B pathway, and activation of cytotoxic T cells showed efficacy in animal models of lupus. Although B cell depletion and blockade of anti-DNA antibodies and T-B cell interaction have shown success in animal models, human studies are currently ongoing to establish the value of several target molecules for treatment of patients with lupus. Ongoing oxidative stress and inflammation lead to accelerated atherosclerosis that emerged as a significant cause of mortality in SLE.
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Cheung YH, Loh C, Pau E, Kim J, Wither J. Insights into the genetic basis and immunopathogenesis of systemic lupus erythematosus from the study of mouse models. Semin Immunol 2009; 21:372-82. [DOI: 10.1016/j.smim.2009.10.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Accepted: 10/23/2009] [Indexed: 01/15/2023]
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Early onset of autoimmune disease by the retroviral integrase inhibitor raltegravir. Proc Natl Acad Sci U S A 2009; 106:20865-70. [PMID: 19923437 DOI: 10.1073/pnas.0908074106] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Raltegravir is a recently, Food and Drug Administration-approved, small-molecule drug that inhibits retroviral integrase, thereby preventing HIV DNA from inserting itself into the human genome. We report here that the activity profile of raltegravir on the replication of murine leukemia virus is similar to that for HIV, and that the drug specifically affects autoimmune disease in mice, in which endogenous retroelements are suspected to play a role. While NZW and BALB/c mice, which do not succumb to autoimmune disease, are not affected by raltegravir, lupus-prone (NZBxNZW) F(1) mice die of glomerulonephritis more than a month earlier than untreated mice. Raltegravir-treated NZB mice, which share the H-2 haplotype with BALB/c mice, but which are predisposed to autoimmune hemolytic anemia, develop auto-antibodies to their red blood cells >3 months earlier than untreated mice of the same strain. Because nonautoimmune mice are not affected by raltegravir, we consider off-target effects unlikely and attribute the exacerbation of autoimmunity to the inhibition of retroviral integrase.
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Santiago-Raber ML, Baudino L, Izui S. Emerging roles of TLR7 and TLR9 in murine SLE. J Autoimmun 2009; 33:231-8. [PMID: 19846276 DOI: 10.1016/j.jaut.2009.10.001] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by B cell hyperactivity leading to the production of various autoantibodies and subsequent development of glomerulonephritis, i.e. lupus nephritis. Among the principal targets of autoantibodies produced in murine SLE are nucleic acid-protein complexes, such as chromatin and ribonucleoproteins, and the envelope glycoprotein gp70 of endogenous retroviruses. The preferential production of these autoantibodies is apparently promoted by the presence of genetic abnormalities leading to defects in the elimination of apoptotic cells and to an enhanced expression of endogenous retroviruses. Moreover, recent studies revealed that the innate receptors TLR7 and TLR9 are critically involved in the activation of dendritic cells and autoreactive B cells through the recognition of endogenous DNA- or RNA-containing antigens and subsequent development of autoimmune responses against nuclear autoantigens. Furthermore, the regulation of autoimmune responses against endogenous retroviral gp70 by TLR7 suggested the implication of endogenous retroviruses in this autoimmune response. Clearly, further elucidation of the precise molecular role of TLR7 and TLR9 in the development of autoimmune responses will help to develop novel therapeutic strategies and targets for SLE.
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Affiliation(s)
- Marie-Laure Santiago-Raber
- Department of Pathology and Immunology, Centre Medical Universitaire, University of Geneva, 1211 Geneva 4, Switzerland
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