51
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An endogenous retroviral element exerts an antiviral innate immune function via the derived lncRNA lnc-ALVE1-AS1. Antiviral Res 2019; 170:104571. [PMID: 31374219 DOI: 10.1016/j.antiviral.2019.104571] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 07/27/2019] [Accepted: 07/29/2019] [Indexed: 11/24/2022]
Abstract
Endogenous retroviruses (ERVs) constitute an important component of animal and human genomes and are usually silenced by epigenetic mechanisms in adult cells. Although ERVs were recently reported to be linked to early development, tumorigenesis and autoimmune disease, their impacts on antiviral innate immunity and the underlying mechanisms have not been elucidated. Here, we provide the first direct evidence of an endogenous retroviral element affecting antiviral innate immunity via its derived antisense long non-coding RNA (lncRNA). We found that an antisense lncRNA, which is called lnc-ALVE1-AS1 and is transcribed from the endogenous avian leukosis virus in chromosome 1 (ALVE1), distinctly inhibited the entry and replication of exogenous retroviruses in chicken embryonic fibroblasts (CEFs). This behaviour is at least in part attributed to the induction of an antiviral innate immune pathway by ALVE1 activation, suggesting that an activated endogenous retroviral element may induce antiviral defence responses via its derived antisense lncRNA. We also found that lnc-ALVE1-AS1 mediated these effects by activating the TLR3 signalling in the cytoplasm. Our results provide novel insights into the antiviral innate immune function of ERVs, suggesting that ERVs may play an important role in antiviral defences and provide new strategies for the development of new vaccines.
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52
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Laffont S, Guéry JC. Deconstructing the sex bias in allergy and autoimmunity: From sex hormones and beyond. Adv Immunol 2019; 142:35-64. [PMID: 31296302 DOI: 10.1016/bs.ai.2019.04.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Men and women differ in their susceptibility to develop autoimmunity and allergy but also in their capacity to cope with infections. Mechanisms responsible for this sexual dimorphism are still poorly documented and probably multifactorial. This review discusses the recent development in our understanding of the cell-intrinsic actions of biological factors linked to sex, sex hormones and sex chromosome complement, on immune cells, which may account for the sex differences in the enhanced susceptibility of women to develop immunological disorders, such as allergic asthma or systemic lupus erythematosus (SLE). We choose to more specifically discuss the impact of sex hormones on the development and function of immune cell populations directly involved in type-2 immunity, and the role of the X-linked Toll like receptor 7 (TLR7) in anti-viral immunity and in SLE. We will also elaborate on the recent evidence demonstrating that TLR7 escapes from X chromosome inactivation in the immune cells of women, and how this may contribute to endow woman immune system with enhanced responsiveness to RNA-virus and susceptibility to SLE.
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Affiliation(s)
- Sophie Laffont
- Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, INSERM, CNRS, UPS, Toulouse, France
| | - Jean-Charles Guéry
- Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, INSERM, CNRS, UPS, Toulouse, France.
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53
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Greenig M. HERVs, immunity, and autoimmunity: understanding the connection. PeerJ 2019; 7:e6711. [PMID: 30984482 PMCID: PMC6452852 DOI: 10.7717/peerj.6711] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 02/28/2019] [Indexed: 12/30/2022] Open
Abstract
Since their discovery in the 1960s, further investigation into endogenous retroviruses (ERVs) has challenged the conventional view of viral sequences as exclusively parasitic elements. Once presumed to be a group of passive genetic relics, it is becoming increasingly clear that this view of ERVs, while generally accurate, is incorrect in many specific cases. Research has identified ERV genes that appear to be co-opted by their mammalian hosts, but the biological function of ERV elements in humans remains a controversial subject. One area that has attracted some attention in this domain is the role of co-opted ERV elements in mammalian immune systems. The relationship between ERVs and human autoimmune diseases has also been investigated, but has historically been treated as a separate topic. This review will summarize the current evidence concerning the phenotypic significance of ERVs, both in the healthy immune system and in manifestations of autoimmunity. Furthermore, it will evaluate the relationship between these fields of study, and propose previously-unexplored molecular mechanisms through which human endogenous retroviruses might contribute to certain autoimmune pathologies. Investigation into these novel mechanisms could further our understanding of the molecular basis of autoimmune disease, and may one day provide new targets for treatment.
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Affiliation(s)
- Matthew Greenig
- Department of Life Sciences, Imperial College London, London, United Kingdom
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54
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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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55
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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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56
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Ottina E, Levy P, Eksmond U, Merkenschlager J, Young GR, Roels J, Stoye JP, Tüting T, Calado DP, Kassiotis G. Restoration of Endogenous Retrovirus Infectivity Impacts Mouse Cancer Models. Cancer Immunol Res 2018; 6:1292-1300. [PMID: 30143537 PMCID: PMC6485373 DOI: 10.1158/2326-6066.cir-18-0038] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 06/19/2018] [Accepted: 08/21/2018] [Indexed: 12/31/2022]
Abstract
Mouse models have been instrumental in establishing fundamental principles of cancer initiation and progression and continue to be invaluable in the discovery and further development of cancer therapies. Nevertheless, important aspects of human disease are imperfectly approximated in mouse models, notably the involvement of endogenous retroviruses (ERVs). Replication-defective ERVs, present in both humans and mice, may affect tumor development and antitumor immunity through mechanisms not involving infection. Here, we revealed an adverse effect of murine ERVs with restored infectivity on the behavior of mouse cancer models. In contrast to human cancer, where infectious ERVs have never been detected, we found that ERV infectivity was frequently restored in transplantable, as well as genetic, mouse cancer models. Such replication-competent, ERV-derived retroviruses were responsible for unusually high expression of retroviral nucleic acids and proteins in mouse cancers. Infectious ERV-derived retroviruses produced by mouse cancer cells could directly infect tumor-infiltrating host immune cells and fundamentally modified the host's immune defenses to cancer, as well as the outcome of immunotherapy. Therefore, infectious retroviruses, variably arising in mouse cancer models, but not in human cancer, have the potential to confound many immunologic studies and should be considered as a variable, if not altogether avoided. Cancer Immunol Res; 6(11); 1292-300. ©2018 AACR.
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MESH Headings
- Animals
- Cell Line, Tumor
- Endogenous Retroviruses/pathogenicity
- Female
- Leukemia Virus, Murine/genetics
- Leukemia Virus, Murine/pathogenicity
- Lymphocytes, Tumor-Infiltrating/pathology
- Male
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Mice, Transgenic
- Neoplasms, Experimental/immunology
- Neoplasms, Experimental/pathology
- Neoplasms, Experimental/virology
- Positive Regulatory Domain I-Binding Factor 1/genetics
- Proto-Oncogene Proteins B-raf/genetics
- Retroviridae Infections/virology
- Viral Tropism/physiology
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Affiliation(s)
- Eleonora Ottina
- Retroviral Immunology, The Francis Crick Institute, London, UK
| | - Prisca Levy
- Retroviral Immunology, The Francis Crick Institute, London, UK
| | - Urszula Eksmond
- Retroviral Immunology, The Francis Crick Institute, London, UK
| | | | - George R Young
- Retrovirus-Host Interactions, The Francis Crick Institute, London, UK
| | - Juliette Roels
- Retroviral Immunology, The Francis Crick Institute, London, UK
| | - Jonathan P Stoye
- Retrovirus-Host Interactions, The Francis Crick Institute, London, UK
- Department of Medicine, Faculty of Medicine, Imperial College London, London, UK
| | - Thomas Tüting
- Laboratory of Experimental Dermatology, Department of Dermatology, University of Magdeburg, Magdeburg, Germany
| | - Dinis P Calado
- Immunity and Cancer Laboratory, The Francis Crick Institute, London, UK
| | - George Kassiotis
- Retroviral Immunology, The Francis Crick Institute, London, UK.
- Department of Medicine, Faculty of Medicine, Imperial College London, London, UK
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57
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Grandi N, Tramontano E. Human Endogenous Retroviruses Are Ancient Acquired Elements Still Shaping Innate Immune Responses. Front Immunol 2018; 9:2039. [PMID: 30250470 PMCID: PMC6139349 DOI: 10.3389/fimmu.2018.02039] [Citation(s) in RCA: 180] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/20/2018] [Indexed: 12/25/2022] Open
Abstract
About 8% of our genome is composed of sequences with viral origin, namely human Endogenous Retroviruses (HERVs). HERVs are relics of ancient infections that affected the primates' germ line along the last 100 million of years, and became stable elements at the interface between self and foreign DNA. Intriguingly, HERV co-evolution with the host led to the domestication of activities previously devoted to the retrovirus life cycle, providing novel cellular functions. For example, selected HERV envelope proteins have been coopted for pregnancy-related purposes, and proviral Long Terminal Repeats participate in the transcriptional regulation of various cellular genes. Given the HERV persistence in the host genome and its basal expression in most healthy tissues, it is reasonable that human defenses should prevent HERV-mediated immune activation. Despite this, HERVs and their products (including RNA, cytosolic DNA, and proteins) are still able to modulate and be influenced by the host immune system, fascinatingly suggesting a central role in the evolution and functioning of the human innate immunity. Indeed, HERV sequences had been major contributors in shaping and expanding the interferon network, dispersing inducible genes that have been occasionally domesticated in various mammalian lineages. Also the HERV integration within or near to genes encoding for critical immune factors has been shown to influence their activity, or to be responsible for their polymorphic variation in the human population, such as in the case of an HERV-K(HML10) provirus in the major histocompatibility complex region. In addition, HERV expressed products have been shown to modulate innate immunity effectors, being therefore often related on the one side to inflammatory and autoimmune disorders, while on the other side to the control of excessive immune activation through their immunosuppressive properties. Finally, HERVs have been proposed to establish a protective effect against exogenous infections. The present review summarizes the involvement of HERVs and their products in innate immune responses, describing how their intricate interplay with the first line of human defenses can actively contribute either to the host protection or to his damage, implying a subtle balance between the persistence of HERV expression and the maintenance of a basal immune alert.
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Affiliation(s)
- Nicole Grandi
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
| | - Enzo Tramontano
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy.,Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Cagliari, Italy
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58
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Ishak CA, Classon M, De Carvalho DD. Deregulation of Retroelements as an Emerging Therapeutic Opportunity in Cancer. Trends Cancer 2018; 4:583-597. [DOI: 10.1016/j.trecan.2018.05.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 05/22/2018] [Accepted: 05/24/2018] [Indexed: 12/26/2022]
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59
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Le Gallou S, Zhou Z, Thai LH, Fritzen R, de Los Aires AV, Mégret J, Yu P, Kitamura D, Bille E, Tros F, Nassif X, Charbit A, Weller S, Weill JC, Reynaud CA. A splenic IgM memory subset with antibacterial specificities is sustained from persistent mucosal responses. J Exp Med 2018; 215:2035-2053. [PMID: 29959173 PMCID: PMC6080908 DOI: 10.1084/jem.20180977] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/08/2018] [Accepted: 06/18/2018] [Indexed: 12/12/2022] Open
Abstract
Le Gallou et al. use an AID fate-mapping model to identify an IgM memory population in the spleen of unimmunized mice, originating from persistent gut immune responses and endowed with cross-reactivity against bacteria. To what extent immune responses against the gut flora are compartmentalized within mucosal tissues in homeostatic conditions remains a much-debated issue. We describe here, based on an inducible AID fate-mapping mouse model, that systemic memory B cell subsets, including mainly IgM+ B cells in spleen, together with IgA+ plasma cells in spleen and bone marrow, are generated in mice in the absence of deliberate immunization. While the IgA component appears dependent on the gut flora, IgM memory B cells are still generated in germ-free mice, albeit to a reduced extent. Clonal relationships and renewal kinetics after anti-CD20 treatment reveal that this long-lasting splenic population is mainly sustained by output of B cell clones persisting in mucosal germinal centers. IgM-secreting hybridomas established from splenic IgM memory B cells showed reactivity against various bacterial isolates and endogenous retroviruses. Ongoing activation of B cells in gut-associated lymphoid tissues thus generates a diversified systemic compartment showing long-lasting clonal persistence and protective capacity against systemic bacterial infections.
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Affiliation(s)
- Simon Le Gallou
- Team "Development of the Immune System," Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151-Centre National de la Recherche Scientifique UMR 8253, Faculté de Médecine Paris Descartes, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Zhicheng Zhou
- Team "Development of the Immune System," Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151-Centre National de la Recherche Scientifique UMR 8253, Faculté de Médecine Paris Descartes, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Lan-Huong Thai
- Team "Development of the Immune System," Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151-Centre National de la Recherche Scientifique UMR 8253, Faculté de Médecine Paris Descartes, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Remi Fritzen
- Team "Development of the Immune System," Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151-Centre National de la Recherche Scientifique UMR 8253, Faculté de Médecine Paris Descartes, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Alba Verge de Los Aires
- Team "Development of the Immune System," Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151-Centre National de la Recherche Scientifique UMR 8253, Faculté de Médecine Paris Descartes, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Jérôme Mégret
- Flow Cytometry Core Facility, Structure Fédérative de Recherche Necker, Institut National de la Santé et de la Recherche Médicale US24-Centre National de la Recherche Scientifique UMS 3633, Faculté de Médecine Paris Descartes, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Philipp Yu
- Institute of Immunology, Philipps-Universität Marburg, Marburg, Germany
| | - Daisuke Kitamura
- Division of Molecular Biology, Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Chiba, Japan
| | - Emmanuelle Bille
- Team "Pathogeny of Systemic Infections", Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151-Centre National de la Recherche Scientifique UMR 8253, Faculté de Médecine Paris Descartes, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Service de Microbiologie, Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Fabiola Tros
- Team "Pathogeny of Systemic Infections", Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151-Centre National de la Recherche Scientifique UMR 8253, Faculté de Médecine Paris Descartes, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Xavier Nassif
- Team "Pathogeny of Systemic Infections", Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151-Centre National de la Recherche Scientifique UMR 8253, Faculté de Médecine Paris Descartes, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Service de Microbiologie, Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Alain Charbit
- Team "Pathogeny of Systemic Infections", Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151-Centre National de la Recherche Scientifique UMR 8253, Faculté de Médecine Paris Descartes, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Sandra Weller
- Team "Development of the Immune System," Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151-Centre National de la Recherche Scientifique UMR 8253, Faculté de Médecine Paris Descartes, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Jean-Claude Weill
- Team "Development of the Immune System," Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151-Centre National de la Recherche Scientifique UMR 8253, Faculté de Médecine Paris Descartes, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Claude-Agnès Reynaud
- Team "Development of the Immune System," Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151-Centre National de la Recherche Scientifique UMR 8253, Faculté de Médecine Paris Descartes, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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60
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Kassiotis G, Stoye JP. Making a virtue of necessity: the pleiotropic role of human endogenous retroviruses in cancer. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0277. [PMID: 28893944 PMCID: PMC5597744 DOI: 10.1098/rstb.2016.0277] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2017] [Indexed: 12/18/2022] Open
Abstract
Like all other mammals, humans harbour an astonishing number of endogenous retroviruses (ERVs), as well as other retroelements, embedded in their genome. These remnants of ancestral germline infection with distinct exogenous retroviruses display various degrees of open reading frame integrity and replication capability. Modern day exogenous retroviruses, as well as the infectious predecessors of ERVs, are demonstrably oncogenic. Further, replication-competent ERVs continue to cause cancers in many other species of mammal. Moreover, human cancers are characterized by transcriptional activation of human endogenous retroviruses (HERVs). These observations conspire to incriminate HERVs as causative agents of human cancer. However, exhaustive investigation of cancer genomes suggests that HERVs have entirely lost the ability for re-infection and thus the potential for insertional mutagenic activity. Although there may be non-insertional mechanisms by which HERVs contribute to cancer development, recent evidence also uncovers potent anti-tumour activities exerted by HERV replication intermediates or protein products. On balance, it appears that HERVs, despite their oncogenic past, now represent potential targets for immune-mediated anti-tumour mechanisms. This article is part of the themed issue ‘Human oncogenic viruses’.
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Affiliation(s)
- George Kassiotis
- Retroviral Immunology, The Francis Crick Institute, London, UK .,Department of Medicine, Faculty of Medicine, Imperial College London, London, UK
| | - Jonathan P Stoye
- Retrovirus-Host Interactions, The Francis Crick Institute, London, UK .,Department of Medicine, Faculty of Medicine, Imperial College London, London, UK
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61
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Miyake K, Shibata T, Ohto U, Shimizu T, Saitoh SI, Fukui R, Murakami Y. Mechanisms controlling nucleic acid-sensing Toll-like receptors. Int Immunol 2018; 30:43-51. [DOI: 10.1093/intimm/dxy016] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 02/13/2018] [Indexed: 12/23/2022] Open
Affiliation(s)
- Kensuke Miyake
- Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo, Japan
| | - Takuma Shibata
- Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo, Japan
| | - Umeharu Ohto
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Toshiyuki Shimizu
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Shin-Ichiroh Saitoh
- Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo, Japan
| | - Ryutaro Fukui
- Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo, Japan
| | - Yusuke Murakami
- Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Shirokanedai, Minato-ku, Tokyo, Japan
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62
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Bannert N, Hofmann H, Block A, Hohn O. HERVs New Role in Cancer: From Accused Perpetrators to Cheerful Protectors. Front Microbiol 2018; 9:178. [PMID: 29487579 PMCID: PMC5816757 DOI: 10.3389/fmicb.2018.00178] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 01/25/2018] [Indexed: 02/02/2023] Open
Abstract
Initial indications that retroviruses are connected to neoplastic transformation were seen more than a century ago. This concept has also been tested for endogenized retroviruses (ERVs) that are abundantly expressed in many transformed cells. In healthy cells, ERV expression is commonly prevented by DNA methylation and other epigenetic control mechanisms. ERVs are remnants of former exogenous forms that invaded the germ line of the host and have since been vertically transmitted. Several examples of ERV-induced genomic recombination events and dysregulation of cellular genes that contribute to tumor formation have been well documented. Moreover, evidence is accumulating that certain ERV proteins have oncogenic properties. In contrast to these implications for supporting cancer induction, a recent string of papers has described favorable outcomes of increasing human ERV (HERV) RNA and DNA abundance by treatment of cancer cells with methyltransferase inhibitors. Analogous to an infecting agent, the ERV-derived nucleic acids are sensed in the cytoplasm and activate innate immune responses that drive the tumor cell into apoptosis. This "viral mimicry" induced by epigenetic drugs might offer novel therapeutic approaches to help target cancer cells that are normally difficult to treat using standard chemotherapy. In this review, we discuss both the detrimental and the new beneficial role of HERV reactivation in terms of its implications for cancer.
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Affiliation(s)
- Norbert Bannert
- HIV and Other Retroviruses, Robert Koch Institute, Berlin, Germany
| | - Henning Hofmann
- HIV and Other Retroviruses, Robert Koch Institute, Berlin, Germany
| | - Adriana Block
- HIV and Other Retroviruses, Robert Koch Institute, Berlin, Germany
| | - Oliver Hohn
- HIV and Other Retroviruses, Robert Koch Institute, Berlin, Germany
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IRF9 Prevents CD8 + T Cell Exhaustion in an Extrinsic Manner during Acute Lymphocytic Choriomeningitis Virus Infection. J Virol 2017; 91:JVI.01219-17. [PMID: 28878077 DOI: 10.1128/jvi.01219-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 08/27/2017] [Indexed: 12/13/2022] Open
Abstract
Effective CD8+ T cell responses play an important role in determining the course of a viral infection. Overwhelming antigen exposure can result in suboptimal CD8+ T cell responses, leading to chronic infection. This altered CD8+ T cell differentiation state, termed exhaustion, is characterized by reduced effector function, upregulation of inhibitory receptors, and altered expression of transcription factors. Prevention of overwhelming antigen exposure to limit CD8+ T cell exhaustion is of significant interest for the control of chronic infection. The transcription factor interferon regulatory factor 9 (IRF9) is a component of type I interferon (IFN-I) signaling downstream of the IFN-I receptor (IFNAR). Using acute infection of mice with lymphocytic choriomeningitis virus (LCMV) strain Armstrong, we show here that IRF9 limited early LCMV replication by regulating expression of interferon-stimulated genes and IFN-I and by controlling levels of IRF7, a transcription factor essential for IFN-I production. Infection of IRF9- or IFNAR-deficient mice led to a loss of early restriction of viral replication and impaired antiviral responses in dendritic cells, resulting in CD8+ T cell exhaustion and chronic infection. Differences in the antiviral activities of IRF9- and IFNAR-deficient mice and dendritic cells provided further evidence of IRF9-independent IFN-I signaling. Thus, our findings illustrate a CD8+ T cell-extrinsic function for IRF9, as a signaling factor downstream of IFNAR, in preventing overwhelming antigen exposure resulting in CD8+ T cell exhaustion and, ultimately, chronic infection.IMPORTANCE During early viral infection, overwhelming antigen exposure can cause functional exhaustion of CD8+ T cells and lead to chronic infection. Here we show that the transcription factor interferon regulatory factor 9 (IRF9) plays a decisive role in preventing CD8+ T cell exhaustion. Using acute infection of mice with LCMV strain Armstrong, we found that IRF9 limited early LCMV replication by regulating expression of interferon-stimulated genes and Irf7, encoding a transcription factor crucial for type I interferon (IFN-I) production, as well as by controlling the levels of IFN-I. Infection of IRF9-deficient mice led to a chronic infection that was accompanied by CD8+ T cell exhaustion due to defects extrinsic to T cells. Our findings illustrate an essential role for IRF9, as a mediator downstream of IFNAR, in preventing overwhelming antigen exposure causing CD8+ T cell exhaustion and leading to chronic viral infection.
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64
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Douville RN, Nath A. Human Endogenous Retrovirus-K and TDP-43 Expression Bridges ALS and HIV Neuropathology. Front Microbiol 2017; 8:1986. [PMID: 29075249 PMCID: PMC5641584 DOI: 10.3389/fmicb.2017.01986] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 09/27/2017] [Indexed: 12/12/2022] Open
Abstract
Despite the repetitive association of endogenous retroviruses in human disease, the mechanisms behind their pathological contributions remain to be resolved. Here we discuss how neuronal human endogenous retrovirus-K (HERV-K) expression in human immunodeficiency virus (HIV)-infected individuals is a distinct pathological aspect of HIV-associated neurological conditions, such as HIV encephalitis and HIV-associated neurocognitive disorders. Enhanced neuronal HERV-K levels were observed in the majority of HIV-infected individuals, and to a higher degree in brain tissue marked by HIV replication. Moreover, we highlight an important neuropathological overlap between amyotrophic lateral sclerosis and HIV encephalitis, that being the formation of neurotoxic TDP-43 deposits in neurons. Herein, we argue for enhanced transdisciplinary research in the field of ERV biology, using an example of how HERV-K expression has novel mechanistic and therapeutic implications for HIV neuropathology.
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Affiliation(s)
- Renée N Douville
- Department of Biology, University of Winnipeg, Winnipeg, MB, Canada.,Department of Immunology, University of Manitoba, Winnipeg, MB, Canada
| | - Avindra Nath
- Section of Infections of the Nervous System, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
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65
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Presence of a Shared 5'-Leader Sequence in Ancestral Human and Mammalian Retroviruses and Its Transduction into Feline Leukemia Virus. J Virol 2017; 91:JVI.00829-17. [PMID: 28768854 DOI: 10.1128/jvi.00829-17] [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: 06/02/2017] [Accepted: 07/24/2017] [Indexed: 12/13/2022] Open
Abstract
Recombination events induce significant genetic changes, and this process can result in virus genetic diversity or in the generation of novel pathogenicity. We discovered a new recombinant feline leukemia virus (FeLV) gag gene harboring an unrelated insertion, termed the X region, which was derived from Felis catus endogenous gammaretrovirus 4 (FcERV-gamma4). The identified FcERV-gamma4 proviruses have lost their coding capabilities, but some can express their viral RNA in feline tissues. Although the X-region-carrying recombinant FeLVs appeared to be replication-defective viruses, they were detected in 6.4% of tested FeLV-infected cats. All isolated recombinant FeLV clones commonly incorporated a middle part of the FcERV-gamma4 5'-leader region as an X region. Surprisingly, a sequence corresponding to the portion contained in all X regions is also present in at least 13 endogenous retroviruses (ERVs) observed in the cat, human, primate, and pig genomes. We termed this shared genetic feature the commonly shared (CS) sequence. Despite our phylogenetic analysis indicating that all CS-sequence-carrying ERVs are classified as gammaretroviruses, no obvious closeness was revealed among these ERVs. However, the Shannon entropy in the CS sequence was lower than that in other parts of the provirus genome. Notably, the CS sequence of human endogenous retrovirus T had 73.8% similarity with that of FcERV-gamma4, and specific signals were detected in the human genome by Southern blot analysis using a probe for the FcERV-gamma4 CS sequence. Our results provide an interesting evolutionary history for CS-sequence circulation among several distinct ancestral viruses and a novel recombined virus over a prolonged period.IMPORTANCE Recombination among ERVs or modern viral genomes causes a rapid evolution of retroviruses, and this phenomenon can result in the serious situation of viral disease reemergence. We identified a novel recombinant FeLV gag gene that contains an unrelated sequence, termed the X region. This region originated from the 5' leader of FcERV-gamma4, a replication-incompetent feline ERV. Surprisingly, a sequence corresponding to the X region is also present in the 5' portion of other ERVs, including human endogenous retroviruses. Scattered copies of the ERVs carrying the unique genetic feature, here named the commonly shared (CS) sequence, were found in each host genome, suggesting that ancestral viruses may have captured and maintained the CS sequence. More recently, a novel recombinant FeLV hijacked the CS sequence from inactivated FcERV-gamma4 as the X region. Therefore, tracing the CS sequences can provide unique models for not only the modern reservoir of new recombinant viruses but also the genetic features shared among ancient retroviruses.
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66
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Achleitner M, Kleefisch M, Hennig A, Peschke K, Polikarpova A, Oertel R, Gabriel B, Schulze L, Lindeman D, Gerbaulet A, Fiebig U, Lee-Kirsch MA, Roers A, Behrendt R. Lack of Trex1 Causes Systemic Autoimmunity despite the Presence of Antiretroviral Drugs. THE JOURNAL OF IMMUNOLOGY 2017; 199:2261-2269. [PMID: 28835460 DOI: 10.4049/jimmunol.1700714] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/26/2017] [Indexed: 01/25/2023]
Abstract
Biallelic mutations of three prime repair exonuclease 1 (TREX1) cause the lupus-like disease Aicardi-Goutières syndrome in which accumulation of a yet unknown endogenous DNA substrate of TREX1 triggers a cyclic GMP-AMP synthase-dependent type I IFN response and systemic autoimmunity. Products of reverse transcription originating from endogenous retroelements have been suggested to be a major substrate for TREX1, and reverse transcriptase inhibitors (RTIs) were proposed as a therapeutic option in autoimmunity ensuing from defects of TREX1. In this study, we treated Trex1-/- mice with RTIs. The serum RTI levels reached were sufficient to block retrotransposition of endogenous retroelements. However, the treatment did not reduce the spontaneous type I IFN response and did not ameliorate lethal inflammation. Furthermore, long interspersed nuclear elements 1 retrotransposition was not enhanced in the absence of Trex1. Our data do not support the concept of retroelement-derived cDNA as key triggers of systemic autoimmunity in Trex1-deficient humans and mice and motivate the continuing search for the pathogenic IFN-inducing Trex1 substrate.
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Affiliation(s)
- Martin Achleitner
- Institute for Immunology, Medical Faculty Carl Gustav Carus, Technical University of Dresden, 01307 Dresden, Germany
| | - Martin Kleefisch
- Institute for Immunology, Medical Faculty Carl Gustav Carus, Technical University of Dresden, 01307 Dresden, Germany
| | - Alexander Hennig
- Institute for Immunology, Medical Faculty Carl Gustav Carus, Technical University of Dresden, 01307 Dresden, Germany
| | - Katrin Peschke
- Institute for Immunology, Medical Faculty Carl Gustav Carus, Technical University of Dresden, 01307 Dresden, Germany
| | - Anastasia Polikarpova
- Institute for Immunology, Medical Faculty Carl Gustav Carus, Technical University of Dresden, 01307 Dresden, Germany
| | - Reinhard Oertel
- Institute of Clinical Pharmacology, Medical Faculty Carl Gustav Carus, Technical University of Dresden, 01307 Dresden, Germany
| | - Benjamin Gabriel
- Division for HIV and Other Retroviruses, Department of Infectious Diseases, Robert Koch Institute, 13353 Berlin, Germany
| | - Livia Schulze
- Institute for Immunology, Medical Faculty Carl Gustav Carus, Technical University of Dresden, 01307 Dresden, Germany
| | - Dirk Lindeman
- Institute of Virology, Medical Faculty Carl Gustav Carus, Technical University of Dresden, 01307 Dresden, Germany; and
| | - Alexander Gerbaulet
- Institute for Immunology, Medical Faculty Carl Gustav Carus, Technical University of Dresden, 01307 Dresden, Germany
| | - Uwe Fiebig
- Division for HIV and Other Retroviruses, Department of Infectious Diseases, Robert Koch Institute, 13353 Berlin, Germany
| | - Min Ae Lee-Kirsch
- Molecular Pediatrics, Department of Pediatrics, Medical Faculty Carl Gustav Carus, Technical University of Dresden, 01307 Dresden, Germany
| | - Axel Roers
- Institute for Immunology, Medical Faculty Carl Gustav Carus, Technical University of Dresden, 01307 Dresden, Germany
| | - Rayk Behrendt
- Institute for Immunology, Medical Faculty Carl Gustav Carus, Technical University of Dresden, 01307 Dresden, Germany;
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67
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Tie CHC, Rowe HM. Epigenetic control of retrotransposons in adult tissues: implications for immune regulation. Curr Opin Virol 2017; 25:28-33. [DOI: 10.1016/j.coviro.2017.06.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/26/2017] [Accepted: 06/19/2017] [Indexed: 12/29/2022]
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68
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Yasuda M, Ogura T, Goto T, Yagoto M, Kamai Y, Shimomura C, Hayashimoto N, Kiyokawa Y, Shinohara H, Takahashi R, Kawai K. Incidence of spontaneous lymphomas in non-experimental NOD/Shi-scid, IL-2Rγ null (NOG) mice. Exp Anim 2017; 66:425-435. [PMID: 28679969 PMCID: PMC5682355 DOI: 10.1538/expanim.17-0034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Severely immunodeficient NOD/Shi-scid, IL-2Rγnull (NOG) mice provide an in vivo model for human cell/tissue transplantation studies. NOG mice were established by combining interleukin-2 receptor-γ chain knockout mice and NOD/Shi-scid mice. They exhibit a high incidence of thymic lymphomas and immunoglobulin (Ig) leakiness. In this study, we assessed the incidence of malignant lymphomas and the occurrence of leakiness in 2,184 non-experimental NOG retired breeder mice aged 16-40 weeks. We established that the total incidence of lymphomas was only 0.60% (13/2,184). Most lymphomas (10/13) occurred in female mice by the age of around 25 weeks. No mice developed Ig leakiness. All lymphomas were derived from the thymus, and consisted mainly of CD3-positive and CD45R-negative lymphoblastic-like cells. Therefore, based on the absence of Ig leakiness and a very low incidence of lymphomas, including thymic lymphomas, NOG mice may be useful in regeneration medicine for xenotransplantation of human embryonic stem (ES) cells or induced pluripotent stem (iPS) cells, and in transplantation experiments involving tumor cells.
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Affiliation(s)
- Masahiko Yasuda
- Pathology Analysis Center, Central Institute for Experimental Animals (CIEA), 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
| | - Tomoyuki Ogura
- Animal Resources Center, Central Institute for Experimental Animals (CIEA), 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
| | - Takayuki Goto
- Technical Service Department, CLEA Japan, Inc., 4839-23 Kitayama, Fujinomiya, Shizuoka 418-0112, Japan
| | - Mika Yagoto
- Pathology Analysis Center, Central Institute for Experimental Animals (CIEA), 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
| | - Yoko Kamai
- Pathology Analysis Center, Central Institute for Experimental Animals (CIEA), 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
| | - Chie Shimomura
- Technical Service Department, CLEA Japan, Inc., 4839-23 Kitayama, Fujinomiya, Shizuoka 418-0112, Japan
| | - Nobuhito Hayashimoto
- ICLAS Monitoring Center, Central Institute for Experimental Animals (CIEA), 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
| | - Yukito Kiyokawa
- Technical Service Department, CLEA Japan, Inc., 4839-23 Kitayama, Fujinomiya, Shizuoka 418-0112, Japan
| | - Hideki Shinohara
- Technical Service Department, CLEA Japan, Inc., 4839-23 Kitayama, Fujinomiya, Shizuoka 418-0112, Japan
| | - Riichi Takahashi
- Animal Resources Center, Central Institute for Experimental Animals (CIEA), 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
| | - Kenji Kawai
- Pathology Analysis Center, Central Institute for Experimental Animals (CIEA), 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
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69
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Coskran TM, Jiang Z, Klaunig JE, Mager DL, Obert L, Robertson A, Tsinoremas N, Wang Z, Gosink M. Induction of endogenous retroelements as a potential mechanism for mouse-specific drug-induced carcinogenicity. PLoS One 2017; 12:e0176768. [PMID: 28472135 PMCID: PMC5417610 DOI: 10.1371/journal.pone.0176768] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 04/17/2017] [Indexed: 11/23/2022] Open
Abstract
A number of chemical compounds have been shown to induce liver tumors in mice but not in other species. While several mechanisms for this species-specific tumorigenicity have been proposed, no definitive mechanism has been established. We examined the effects of the nongenotoxic rodent hepatic carcinogen, WY-14,643, in male mice from a high liver tumor susceptible strain (C3H/HeJ), and from a low tumor susceptible strain (C57BL/6). WY-14,643, a PPARα activator induced widespread increases in the expression of some endogenous retroelements, namely members of LTR and LINE elements in both strains. The expression of a number of known retroviral defense genes was also elevated. We also demonstrated that basal immune-mediated viral defense was elevated in C57BL/6 mice (the resistant strain) and that WY-14,643 further activated those immuno-defense processes. We propose that the previously reported >100X activity of retroelements in mice drives mouse-specific tumorigenicity. We also propose that C57BL/6's competent immune to retroviral activation allows it to remove cells before the activation of these elements can result in significant chromosomal insertions and mutation. Finally, we showed that WY-14,643 treatment induced gene signatures of DNA recombination in the sensitive C3H/HeJ strain.
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Affiliation(s)
- Timothy M. Coskran
- Drug Safety Research & Development, Pfizer Inc., Groton, Connecticut, United States of America
| | - Zhijie Jiang
- Department of Computer Science, University of Miami, Miami, Florida, United States of America
| | - James E. Klaunig
- Environmental Health, Indiana University, Bloomington, Indiana, United States of America
| | - Dixie L. Mager
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Leslie Obert
- GlaxoSmithKline plc, King of Prussia, Pennsylvania, United States of America
| | - Andrew Robertson
- Drug Safety Research & Development, Pfizer Inc., Groton, Connecticut, United States of America
| | - Nicholas Tsinoremas
- Department of Computer Science, University of Miami, Miami, Florida, United States of America
| | - Zemin Wang
- Environmental Health, Indiana University, Bloomington, Indiana, United States of America
| | - Mark Gosink
- Drug Safety Research & Development, Pfizer Inc., Groton, Connecticut, United States of America
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70
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Kinowaki K, Soejima Y, Kumagai A, Kondo F, Sano K, Fujii T, Kitagawa M, Fukusato T. Clinical and pathological significance of myeloid differentiation factor 88 expression in human hepatocellular carcinoma tissues. Pathol Int 2017; 67:256-263. [PMID: 28370778 DOI: 10.1111/pin.12529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 03/09/2017] [Indexed: 12/23/2022]
Abstract
The innate immune system, which includes toll-like receptor (TLR) signaling, plays an important role in inflammation and oncogenesis. Although TLR common adaptor myeloid differentiation factor 88 (MyD88) is known to have multiple effects on carcinogenesis, the role of MyD88 in hepatocarcinogenesis remains unknown. In this study, MyD88 expression was examined in 105 samples of human hepatocellular carcinoma (HCC) tissue by immunohistochemistry, Western blot, and quantitative reverse-transcriptase polymerase chain reaction methods. The relationships between MyD88 expression and clinical and pathological parameters were analyzed. The results showed that attenuated expression of MyD88 in HCC tissue tumor cells was significantly related to hepatitis B virus infection, large tumor size, positive vascular invasion, and intrahepatic metastasis (P < 0.05). Western blot analysis of MyD88 protein in nine normal livers and 28 HCCs showed gender disparity (P < 0.01, P < 0.05), and attenuated expression in cirrhotic livers (P < 0.05). Low expression of MyD88 mRNA was evident in HCCs with vascular invasion (P < 0.01). In contrast to previous reports, these results suggest that attenuated expression of MyD88 in HCC is associated with tumor progression.
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Affiliation(s)
- Keiichi Kinowaki
- General Medical Education and Research Center, Teikyo University, Tokyo, Japan.,Department of Comprehensive Pathology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.,Department of Pathology, Toranomon Hospital, Tokyo, Japan
| | - Yurie Soejima
- General Medical Education and Research Center, Teikyo University, Tokyo, Japan.,Department of Molecular Pathology, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Arisa Kumagai
- Department of Pathology, Teikyo University School of Medicine, Tokyo, Japan
| | - Fukuo Kondo
- Department of Pathology, Toranomon Hospital, Tokyo, Japan.,Department of Pathology, Teikyo University Hospital, Tokyo, Japan
| | - Keiji Sano
- Department of Surgery, Teikyo University School of Medicine, Tokyo, Japan
| | - Takeshi Fujii
- Department of Pathology, Toranomon Hospital, Tokyo, Japan
| | - Masanobu Kitagawa
- Department of Comprehensive Pathology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
| | - Toshio Fukusato
- General Medical Education and Research Center, Teikyo University, Tokyo, Japan.,Department of Pathology, Toranomon Hospital, Tokyo, Japan.,Department of Pathology, Teikyo University School of Medicine, Tokyo, Japan
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71
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Abstract
Organisms throughout biology need to maintain the integrity of their genome. From bacteria to vertebrates, life has established sophisticated mechanisms to detect and eliminate foreign genetic material or to restrict its function and replication. Tremendous progress has been made in the understanding of these mechanisms which keep foreign or unwanted nucleic acids from viruses or phages in check. Mechanisms reach from restriction-modification systems and CRISPR/Cas in bacteria and archaea to RNA interference and immune sensing of nucleic acids, altogether integral parts of a system which is now appreciated as nucleic acid immunity. With inherited receptors and acquired sequence information, nucleic acid immunity comprises innate and adaptive components. Effector functions include diverse nuclease systems, intrinsic activities to directly restrict the function of foreign nucleic acids (e.g., PKR, ADAR1, IFIT1), and extrinsic pathways to alert the immune system and to elicit cytotoxic immune responses. These effects act in concert to restrict viral replication and to eliminate virus-infected cells. The principles of nucleic acid immunity are highly relevant for human disease. Besides its essential contribution to antiviral defense and restriction of endogenous retroelements, dysregulation of nucleic acid immunity can also lead to erroneous detection and response to self nucleic acids then causing sterile inflammation and autoimmunity. Even mechanisms of nucleic acid immunity which are not established in vertebrates are relevant for human disease when they are present in pathogens such as bacteria, parasites, or helminths or in pathogen-transmitting organisms such as insects. This review aims to provide an overview of the diverse mechanisms of nucleic acid immunity which mostly have been looked at separately in the past and to integrate them under the framework nucleic acid immunity as a basic principle of life, the understanding of which has great potential to advance medicine.
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Affiliation(s)
- G Hartmann
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital, University of Bonn, Bonn, Germany.
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72
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Ishak CA, Marshall AE, Passos DT, White CR, Kim SJ, Cecchini MJ, Ferwati S, MacDonald WA, Howlett CJ, Welch ID, Rubin SM, Mann MRW, Dick FA. An RB-EZH2 Complex Mediates Silencing of Repetitive DNA Sequences. Mol Cell 2016; 64:1074-1087. [PMID: 27889452 DOI: 10.1016/j.molcel.2016.10.021] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 08/17/2016] [Accepted: 10/17/2016] [Indexed: 12/21/2022]
Abstract
Repetitive genomic regions include tandem sequence repeats and interspersed repeats, such as endogenous retroviruses and LINE-1 elements. Repressive heterochromatin domains silence expression of these sequences through mechanisms that remain poorly understood. Here, we present evidence that the retinoblastoma protein (pRB) utilizes a cell-cycle-independent interaction with E2F1 to recruit enhancer of zeste homolog 2 (EZH2) to diverse repeat sequences. These include simple repeats, satellites, LINEs, and endogenous retroviruses as well as transposon fragments. We generated a mutant mouse strain carrying an F832A mutation in Rb1 that is defective for recruitment to repetitive sequences. Loss of pRB-EZH2 complexes from repeats disperses H3K27me3 from these genomic locations and permits repeat expression. Consistent with maintenance of H3K27me3 at the Hox clusters, these mice are developmentally normal. However, susceptibility to lymphoma suggests that pRB-EZH2 recruitment to repetitive elements may be cancer relevant.
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Affiliation(s)
- Charles A Ishak
- London Regional Cancer Program, London, ON N6A 4L6, Canada; Department of Biochemistry, Western University, London, ON N6A 3K7, Canada
| | - Aren E Marshall
- London Regional Cancer Program, London, ON N6A 4L6, Canada; Department of Biochemistry, Western University, London, ON N6A 3K7, Canada
| | - Daniel T Passos
- London Regional Cancer Program, London, ON N6A 4L6, Canada; Department of Biochemistry, Western University, London, ON N6A 3K7, Canada
| | - Carlee R White
- Children's Health Research Institute, London, ON N6A 4L6, Canada; Department of Biochemistry, Western University, London, ON N6A 3K7, Canada
| | - Seung J Kim
- London Regional Cancer Program, London, ON N6A 4L6, Canada; Department of Biochemistry, Western University, London, ON N6A 3K7, Canada
| | - Matthew J Cecchini
- London Regional Cancer Program, London, ON N6A 4L6, Canada; Department of Pathology and Laboratory Medicine, Western University, London, ON N6A 3K7, Canada
| | - Sara Ferwati
- London Regional Cancer Program, London, ON N6A 4L6, Canada; Department of Biochemistry, Western University, London, ON N6A 3K7, Canada
| | - William A MacDonald
- Magee-Womens Research Institute, Pittsburgh, PA 15213, USA; Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Christopher J Howlett
- Department of Pathology and Laboratory Medicine, Western University, London, ON N6A 3K7, Canada
| | - Ian D Welch
- Animal Care Services, University of British Columbia, Vancouver, BC V6T1Z4, Canada
| | - Seth M Rubin
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Mellissa R W Mann
- Magee-Womens Research Institute, Pittsburgh, PA 15213, USA; Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Frederick A Dick
- London Regional Cancer Program, London, ON N6A 4L6, Canada; Children's Health Research Institute, London, ON N6A 4L6, Canada; Department of Biochemistry, Western University, London, ON N6A 3K7, Canada.
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73
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Expression patterns of endogenous avian retrovirus ALVE1 and its response to infection with exogenous avian tumour viruses. Arch Virol 2016; 162:89-101. [PMID: 27686071 DOI: 10.1007/s00705-016-3086-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 09/21/2016] [Indexed: 02/01/2023]
Abstract
Endogenous retroviruses (ERVs) are genomic elements that are present in a wide range of vertebrates and have been implicated in a variety of human diseases, including cancer. However, the characteristic expression patterns of ERVs, particularly in virus-induced tumours, is not fully clear. DNA methylation was analysed by bisulfite pyrosequencing, and gene expression was analysed by RT-qPCR. In this study, we first found that the endogenous avian retrovirus ALVE1 was highly expressed in some chicken tissues (including the heart, bursa, thymus, and spleen) at 2 days of age, but its expression was markedly decreased at 35 days of age. In contrast, the CpG methylation level of ALVE1 was significantly lower in heart and bursa at 2 days than at 35 days of age. Moreover, we found that the expression of ALVE1 was significantly inhibited in chicken embryo fibroblast cells (CEFs) and MSB1 cells infected with avian leukosis virus subgroup J (ALVJ) and reticuloendotheliosis virus (REV) at the early stages of infection. In contrast, the expression of the ALVE1 env gene was significantly induced in CEFs and MSB1 cells infected with Marek's disease virus (MDV). However, the methylation and expression levels of the ALVE1 long terminal repeat (LTR) did not show obvious alterations in response to viral infection. The present study revealed the expression patterns of ALVE1 in a variety of chicken organs and tissues and in chicken cells in response to avian tumour virus infection. These findings may be of significance for understanding the role and function of ERVs that are present in the host genome.
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74
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Existence of Two Distinct Infectious Endogenous Retroviruses in Domestic Cats and Their Different Strategies for Adaptation to Transcriptional Regulation. J Virol 2016; 90:9029-45. [PMID: 27466428 DOI: 10.1128/jvi.00716-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Accepted: 07/22/2016] [Indexed: 01/17/2023] Open
Abstract
UNLABELLED Endogenous retroviruses (ERVs) are the remnants of ancient retroviral infections of germ cells. Previous work identified one of the youngest feline ERV groups, ERV-DC, and reported that two ERV-DC loci, ERV-DC10 and ERV-DC18 (ERV-DC10/DC18), can replicate in cultured cells. Here, we identified another replication-competent provirus, ERV-DC14, on chromosome C1q32. ERV-DC14 differs from ERV-DC10/DC18 in its phylogeny, receptor usage, and, most notably, transcriptional activities; although ERV-DC14 can replicate in cultured cells, it cannot establish a persistent infection owing to its low transcriptional activity. Furthermore, we examined ERV-DC transcription and its regulation in feline tissues. Quantitative reverse transcription-PCR (RT-PCR) detected extremely low ERV-DC10 expression levels in feline tissues, and bisulfite sequencing showed that 5' long terminal repeats (LTRs) of ERV-DC10/DC18 are significantly hypermethylated in feline blood cells. Reporter assays found that the 5'-LTR promoter activities of ERV-DC10/DC18 are high, whereas that of ERV-DC14 is low. This difference in promoter activity is due to a single substitution from A to T in the LTR, and reverse mutation at this nucleotide in ERV-DC14 enhanced its replication and enabled it to persistently infect cultured cells. Therefore, ERV-DC LTRs can be divided into two types based on this nucleotide, the A type or T type, which have strong or attenuated promoter activity, respectively. Notably, ERV-DCs with T-type LTRs, such as ERV-DC14, have expanded in the cat genome significantly more than A-type ERV-DCs, despite their low promoter activities. Our results provide insights into how the host controls potentially infectious ERVs and, conversely, how ERVs adapt to and invade the host genome. IMPORTANCE The domestic cat genome contains many endogenous retroviruses, including ERV-DCs. These ERV-DCs have been acquired through germ cell infections with exogenous retroviruses. Some of these ERV-DCs are still capable of producing infectious virions. Hosts must tightly control these ERVs because replication-competent viruses in the genome pose a risk to the host. Here, we investigated how ERV-DCs are adapted by their hosts. Replication-competent viruses with strong promoter activity, such as ERV-DC10 and ERV-DC18, were suppressed by promoter methylation in LTRs. On the other hand, replication-competent viruses with weak promoter activity, such as ERV-DC14, seemed to escape strict control via promoter methylation by the host. Interestingly, ERV-DCs with weak promoter activity, such as ERV-DC14, have expanded in the cat genome significantly more than ERV-DCs with strong promoter activity. Our results improve the understanding of the host-virus conflict and how ERVs adapt in their hosts over time.
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Abstract
In the last 20 years research in Immunology underwent fundamental changes. Most importantly, the identification of the key role of innate immune pattern recognition receptors (PRRs) that recognize evolutionarily conserved molecular patterns on infectious pathogens. This results in priming of innate immune cells, which in turn activate and direct the adaptive immune response. Progress in innate immune recognition instigated the current working hypothesis, that recognition of endogenous ligands by PRRs results in innate immune cell activation (autoinflammation) or activation of adaptive cells, with self-reactive antigen receptors (autoimmunity). In particular, nucleic acid-sensing innate immune receptors seem to be prime candidates for a mechanistic understanding of autoreactive activation of the immune system. However, it remains uncertain what the actual source of nucleic acid ligands is and what other signals are needed to drive activation of autoreactive innate immune cells and break self-tolerance of the adaptive immune system. Here, I will review our present understanding about whether the infection with exogenous retroviruses or the reactivation of endogenous retroviruses might play an etiological role in certain autoimmune conditions of humans and murine experimental models.
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Affiliation(s)
- Philipp Yu
- Institute of Immunology, Philipps-Universität Marburg, Marburg, Germany
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76
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Mavrommatis B, Baudino L, Levy P, Merkenschlager J, Eksmond U, Donnarumma T, Young G, Stoye J, Kassiotis G. Dichotomy between T Cell and B Cell Tolerance to Neonatal Retroviral Infection Permits T Cell Therapy. THE JOURNAL OF IMMUNOLOGY 2016; 197:3628-3638. [PMID: 27647833 PMCID: PMC5073355 DOI: 10.4049/jimmunol.1600734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/05/2016] [Indexed: 11/23/2022]
Abstract
Elucidation of the immune requirements for control or elimination of retroviral infection remains an important aim. We studied the induction of adaptive immunity to neonatal infection with a murine retrovirus, under conditions leading to immunological tolerance. We found that the absence of either maternal or offspring adaptive immunity permitted efficient vertical transmission of the retrovirus. Maternal immunodeficiency allowed the retrovirus to induce central Th cell tolerance in the infected offspring. In turn, this compromised the offspring’s ability to mount a protective Th cell–dependent B cell response. However, in contrast to T cells, offspring B cells were not centrally tolerized and retained their ability to respond to the infection when provided with T cell help. Thus, escape of retrovirus-specific B cells from deletional tolerance offers the opportunity to induce protective retroviral immunity by restoration of retrovirus-specific T cell help, suggesting similar T cell immunotherapies for persistent viral infections.
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Affiliation(s)
- Bettina Mavrommatis
- Retroviral Immunology, The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, United Kingdom
| | - Lucie Baudino
- Retroviral Immunology, The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, United Kingdom
| | - Prisca Levy
- Retroviral Immunology, The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, United Kingdom
| | - Julia Merkenschlager
- Retroviral Immunology, The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, United Kingdom
| | - Urszula Eksmond
- Retroviral Immunology, The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, United Kingdom
| | - Tiziano Donnarumma
- Retroviral Immunology, The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, United Kingdom
| | - George Young
- Retrovirus-Host Interactions, The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, United Kingdom; and
| | - Jonathan Stoye
- Retrovirus-Host Interactions, The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, United Kingdom; and.,Department of Medicine, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
| | - George Kassiotis
- Retroviral Immunology, The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, United Kingdom; .,Department of Medicine, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
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77
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DeFranco AL. Germinal centers and autoimmune disease in humans and mice. Immunol Cell Biol 2016; 94:918-924. [PMID: 27562062 DOI: 10.1038/icb.2016.78] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 08/02/2016] [Indexed: 12/11/2022]
Abstract
Antibodies are involved in the pathogenesis of many autoimmune diseases. Although the mechanisms underlying the antibody response to infection or vaccination are reasonably well understood, we still have a poor understanding of the nature of autoimmune antibody responses. The most well studied are the anti-nuclear antibody responses characteristic of systemic lupus erythematosus and studies over the past decade or so have demonstrated a critical role for signaling by TLR7 and/or TLR9 in B cells to promote these responses. These Toll-like receptors (TLRs) can promote T-cell-independent extrafollicular antibody responses with a heavy-chain class switch and a low degree of somatic mutation, but they can also strongly boost the germinal center response that gives rise to high-affinity antibodies and long-lived plasma cells. TLRs have been shown to enhance affinity maturation in germinal center responses to produce high-affinity neutralizing antibodies in several virus infection models of mice. Although more data are needed, it appears that anti-nuclear antibodies in mouse models of lupus and in lupus patients can be generated by either pathway, provided there are genetic susceptibility alleles that compromise B-cell tolerance at one or another stage. Limited data in other autoimmune diseases suggest that the germinal center response may be the predominant pathway leading to autoantibodies in those diseases. A better understanding of the mechanisms of autoantibody production may ultimately be helpful in the development of targeted therapeutics for lupus or other autoimmune diseases.
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Affiliation(s)
- Anthony L DeFranco
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
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78
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Abstract
The ability to distinguish between self and nonself is the fundamental basis of the immune system in all organisms. The conceptual distinction between self and nonself, however, breaks down when it comes to endogenous retroviruses and other retroelements. While some retroelements retain the virus-like features including the capacity to replicate and reinvade the host genome, most have become inactive through mutations or host epigenetic silencing. And yet, accumulating evidence suggests that endogenous retroelements, both active and inactive, play important roles not only in pathogenesis of immune disorders, but also in proper functioning of the immune system. This review discusses the recent development in our understanding of the interaction between retroelements and the host innate immune system. In particular, it focuses on the impact of retroelement transcripts on the viral RNA sensors such as Toll-like receptors, RIG-I-like receptors, protein kinase R, and the inflammasomes.
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Affiliation(s)
- X Mu
- Harvard Medical School, Boston, MA, United States; Boston Children's Hospital, Boston, MA, United States
| | - S Ahmad
- Harvard Medical School, Boston, MA, United States; Boston Children's Hospital, Boston, MA, United States
| | - S Hur
- Harvard Medical School, Boston, MA, United States; Boston Children's Hospital, Boston, MA, United States.
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79
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Kassiotis G, Stoye JP. Immune responses to endogenous retroelements: taking the bad with the good. Nat Rev Immunol 2016; 16:207-19. [PMID: 27026073 DOI: 10.1038/nri.2016.27] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ultimate form of parasitism and evasion of host immunity is for the parasite genome to enter the germ line of the host species. Retroviruses have invaded the host germ line on the grandest scale, and this is evident in the extraordinary abundance of endogenous retroelements in the genome of all vertebrate species that have been studied. Many of these endogenous retroelements have retained viral characteristics; some also the capacity to replicate and, consequently, the potential to trigger host innate and adaptive immune responses. However, although retroelements are mainly recognized for their pathogenic potential, recent evidence suggests that this 'enemy within' may also have beneficial roles in tuning host immune reactivity. In this Review, we discuss how the immune system recognizes and is shaped by endogenous retroelements.
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Affiliation(s)
- George Kassiotis
- Retroviral Immunology, the Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, UK.,Department of Medicine, Faculty of Medicine, Imperial College London, London W2 1PG, UK
| | - Jonathan P Stoye
- Department of Medicine, Faculty of Medicine, Imperial College London, London W2 1PG, UK.,Retrovirus-Host Interactions, the Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, UK
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Abstract
Immune sensing of foreign nucleic acids among abundant self nucleic acids is a hallmark of virus detection and antiviral defence. Efficient antiviral defence requires a balanced process of sensing foreign nucleic acids and ignoring self nucleic acids. This balance is accomplished by a multilevel, fail-safe system which combines immune sensing of pathogen-specific nucleic acid structures with specific labelling of self nucleic acids and nuclease-mediated degradation. Cellular localization of nucleic acids, nucleic acid secondary structure, nucleic acid sequence and chemical modification all contribute to selective recognition of foreign nucleic acids. Nucleic acid sensing occurs in immune cells and non-immune cells and results in antiviral responses that include the induction of antiviral effector proteins, the secretion of cytokines alarming neighbouring cells, the secretion of chemokines, which attract immune cells, and the induction of cell death. Vertebrate cells cannot completely avoid the occurrence of endogenous self nucleic acid structures with immunostimulatory properties. Therefore, additional mechanisms involving self-nucleic acid modification and nuclease-mediated degradation are necessary to diminish uncontrolled immune activation. Viruses have established sophisticated mechanisms to exploit and adopt endogenous tolerance mechanisms or to avoid the presentation of characteristic molecular features recognized by nucleic acid sensing receptors.
The detection of viruses by the immune system is mediated predominantly by the sensing of nucleic acids. Here, the authors review our current understanding of how this complex immune sensory system discriminates self from non-self nucleic acids to reliably detect pathogenic viruses, and discuss the future perspectives and implications for human disease. Innate immunity against pathogens relies on an array of immune receptors to detect molecular patterns that are characteristic of the pathogens, including receptors that are specialized in the detection of foreign nucleic acids. In vertebrates, nucleic acid sensing is the dominant antiviral defence pathway. Stimulation of nucleic acid receptors results in antiviral immune responses with the production of type I interferon (IFN), as well as the expression of IFN-stimulated genes, which encode molecules such as cell-autonomous antiviral effector proteins. This Review summarizes the tremendous progress that has been made in understanding how this sophisticated immune sensory system discriminates self from non-self nucleic acids in order to reliably detect pathogenic viruses.
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Affiliation(s)
- Martin Schlee
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital, University of Bonn, Sigmund-Freud-Strasse 25, D-53127 Bonn, Germany
| | - Gunther Hartmann
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital, University of Bonn, Sigmund-Freud-Strasse 25, D-53127 Bonn, Germany
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81
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Hanke K, Hohn O, Bannert N. HERV-K(HML-2), a seemingly silent subtenant - but still waters run deep. APMIS 2016; 124:67-87. [PMID: 26818263 DOI: 10.1111/apm.12475] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 10/12/2015] [Indexed: 01/26/2023]
Abstract
A large proportion of the human genome consists of endogenous retroviruses, some of which are well preserved, showing transcriptional activity, and expressing retroviral proteins. The HERV-K(HML-2) family represents the most intact members of these elements, with some having open and intact reading frames for viral proteins and the ability to form virus-like particles. Although generally suppressed in most healthy tissues by a variety of epigenetic processes and antiviral mechanisms, there is evidence that some members of this family are (at least partly) still active - particularly in certain stem cells and various tumors. This raises the possibility of their involvement in tumor induction or in developmental processes. In recent years, many new insights into this fascinating field have been attained, and this review focuses on new discoveries about coevolutionary events and intracellular defense mechanisms against HERV-K(HML-2) activity. We also describe what might occur when these mechanisms fail or become modulated by viral proteins or other viruses and discuss the new vistas opened up by the reconstitution of ancestral viral proteins and even complete HML-2 viruses.
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Affiliation(s)
- Kirsten Hanke
- Department HIV and Other Retroviruses, Robert Koch Institute, Berlin, Germany
| | - Oliver Hohn
- Department HIV and Other Retroviruses, Robert Koch Institute, Berlin, Germany
| | - Norbert Bannert
- Department HIV and Other Retroviruses, Robert Koch Institute, Berlin, Germany
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82
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Abstract
The germinal center response is the delayed but sustained phase of the antibody response that is responsible for producing high-affinity antibodies of the IgG, IgA and/or IgE isotypes. B cells in the germinal center undergo re-iterative cycles of somatic hypermutation of immunoglobulin gene variable regions, clonal expansion, and Darwinian selection for cells expressing higher-affinity antibody variants. Alternatively, selected B cells can terminally differentiate into long-lived plasma cells or into a broad diversity of mutated memory B cells; the former secrete the improved antibodies to fight an infection and to provide continuing protection from re-infection, whereas the latter may jumpstart immune responses to subsequent infections with related but distinct infecting agents. Our understanding of the molecules involved in the germinal center reaction has been informed by studies of human immunodeficiency patients with selective defects in the production of antibodies. Recent studies have begun to reveal how innate immune recognition via Toll-like receptors can enhance the magnitude and selective properties of the germinal center, leading to more effective control of infection by a subset of viruses. Just as early insights into the nature of the germinal center found application in the development of the highly successful conjugate vaccines, more recent insights may find application in the current efforts to develop new generations of vaccines, including vaccines that can induce broadly protective neutralizing antibodies against influenza virus or HIV-1.
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83
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Expression of the env gene from the avian endogenous retrovirus ALVE and regulation by miR-155. Arch Virol 2016; 161:1623-32. [PMID: 27016933 DOI: 10.1007/s00705-016-2833-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/16/2016] [Indexed: 01/17/2023]
Abstract
Endogenous retroviruses (ERVs) are important retroelements that reside in host genomes. However, ERV expression patterns and regulatory mechanisms are poorly understood. In this study, chicken embryo fibroblasts (CEFs) and MSB1 cells infected with Marek's disease virus (MDV) exhibited significantly increased expression of env from the endogenous retrovirus ALVE. In contrast, env expression was significantly lower in CEF and MSB1 cells infected with exogenous avian leukosis virus J (ALVJ) at the early infection stage. Furthermore, env was found to be ubiquitously expressed in various chicken tissues, with high expression in certain tissues at 2 days of age and low levels in most tissues, including immune organs (thymus, spleen and bursa) as well as the brain and heart, at 35 days of age. Sequence analysis revealed miR-155 target sites in env transcripts, which was verified using a firefly luciferase reporter assay, and treatment with miR-155 agomir significantly decreased levels of env transcripts in MSB1 and CEF cells. Together, these findings suggest that the env gene from the endogenous retrovirus ALVE is regulated by miR-155.
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84
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Abstract
Over 40% of mammalian genomes comprise the products of reverse transcription. Among such retrotransposed sequences are those characterized by the presence of long terminal repeats (LTRs), including the endogenous retroviruses (ERVs), which are inherited genetic elements closely resembling the proviruses formed following exogenous retrovirus infection. Sequences derived from ERVs make up at least 8 to 10% of the human and mouse genomes and range from ancient sequences that predate mammalian divergence to elements that are currently still active. In this chapter we describe the discovery, classification and origins of ERVs in mammals and consider cellular mechanisms that have evolved to control their expression. We also discuss the negative effects of ERVs as agents of genetic disease and cancer and review examples of ERV protein domestication to serve host functions, as in placental development. Finally, we address growing evidence that the gene regulatory potential of ERV LTRs has been exploited multiple times during evolution to regulate genes and gene networks. Thus, although recently endogenized retroviral elements are often pathogenic, those that survive the forces of negative selection become neutral components of the host genome or can be harnessed to serve beneficial roles.
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85
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Grabert K, Michoel T, Karavolos MH, Clohisey S, Baillie JK, Stevens MP, Freeman TC, Summers KM, McColl BW. Microglial brain region-dependent diversity and selective regional sensitivities to aging. Nat Neurosci 2016; 19:504-16. [PMID: 26780511 PMCID: PMC4768346 DOI: 10.1038/nn.4222] [Citation(s) in RCA: 809] [Impact Index Per Article: 101.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 12/07/2015] [Indexed: 12/13/2022]
Abstract
Microglia have critical roles in neural development, homeostasis and neuroinflammation and are increasingly implicated in age-related neurological dysfunction. Neurodegeneration often occurs in disease-specific, spatially restricted patterns, the origins of which are unknown. We performed to our knowledge the first genome-wide analysis of microglia from discrete brain regions across the adult lifespan of the mouse, and found that microglia have distinct region-dependent transcriptional identities and age in a regionally variable manner. In the young adult brain, differences in bioenergetic and immunoregulatory pathways were the major sources of heterogeneity and suggested that cerebellar and hippocampal microglia exist in a more immune-vigilant state. Immune function correlated with regional transcriptional patterns. Augmentation of the distinct cerebellar immunophenotype and a contrasting loss in distinction of the hippocampal phenotype among forebrain regions were key features during aging. Microglial diversity may enable regionally localized homeostatic functions but could also underlie region-specific sensitivities to microglial dysregulation and involvement in age-related neurodegeneration.
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Affiliation(s)
- Kathleen Grabert
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Tom Michoel
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
| | | | - Sara Clohisey
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
| | - J Kenneth Baillie
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Mark P Stevens
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Tom C Freeman
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Kim M Summers
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Barry W McColl
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK
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86
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Lytvyak E, Montano-Loza AJ, Mason AL. Combination antiretroviral studies for patients with primary biliary cirrhosis. World J Gastroenterol 2016; 22:349-360. [PMID: 26755881 PMCID: PMC4698497 DOI: 10.3748/wjg.v22.i1.349] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 08/12/2015] [Accepted: 11/09/2015] [Indexed: 02/07/2023] Open
Abstract
Following the characterization of a human betaretrovirus in patients with primary biliary cirrhosis (PBC), pilot studies using antiretroviral therapy have been conducted as proof of principal to establish a link of virus with disease and with the eventual aim to find better adjunct therapies for patients unresponsive to ursodeoxycholic acid. In the first open label pilot study, the reverse transcriptase inhibitor lamivudine had little demonstrable biochemical or histological effect after 1 year. Whereas, lamivudine in combination with zidovudine was associated with a significant reduction in alkaline phosphatase as well as improvement in necroinflammatory score, cholangitis and ductopenia over a 12 mo period. A double blind, multi-center randomized controlled trial using lamivudine with zidovudine for 6 mo confirmed a significant reduction in alkaline phosphatase, ALT and AST in patients on antiviral therapy. However, none of the patients achieved the stringent endpoint criteria for normalization of alkaline phosphatase. Furthermore, some patients developed biochemical rebound consistent with drug resistance. A major fault of these studies has been the inability to measure the viral load in peripheral blood and therefore, provide a direct correlation between improvement of hepatic biochemistry and reduction in viral load. Nevertheless, viral mutants to lamivudine with zidovudine were later characterized in the NOD.c3c4 mouse model of PBC that has been used to test other antiretroviral regimens to betaretrovirus. The combination of tenofovir and emtricitabine reverse transcriptase inhibitors and the HIV protease inhibitor, lopinavir were found to abrogate cholangitis in the NOD.c3c4 mouse model and the same regimen normalized the liver tests in a PBC patient with HIV and human betaretrovirus infection. This combination antiretroviral therapy has now been used in a double blind randomized controlled crossover study for patients with PBC followed by an open label extension study. Only a third of the PBC patients were able to tolerate the lopinavir but those maintained on tenofovir, emtricitabine and lopinavir experienced sustained and clinically meaningful reduction in hepatic biochemistry. While we await the histological and virological evaluation, it is clear that better tolerated regimens of antiretroviral treatment will be required in future clinical trials.
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87
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Raffegerst S, Steer B, Hohloch M, Adler H. Prevention of Tumor Formation by Latent Gammaherpesvirus Infection. PLoS One 2015; 10:e0145678. [PMID: 26714031 PMCID: PMC4699904 DOI: 10.1371/journal.pone.0145678] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 12/07/2015] [Indexed: 11/18/2022] Open
Abstract
Recent reports suggested that chronic herpesvirus infection, as a constituent of the so-called virome, may not only exert harmful effects but may also be beneficial to the host, for example mediating increased resistance to secondary infections or to tumors. To further challenge this concept, specifically regarding increased resistance to tumors, we infected chimeric HLA-DR4-H2-E (DR4) mice, a mouse strain which spontaneously develops hematological tumors, with the rodent herpesvirus murine gammaherpesvirus 68 (MHV-68). Using this model, we observed that infection with wildtype MHV-68 completely prevented tumor formation. This happened, however, at the cost of hyposplenism. In contrast to wildtype infection, infection with a latency-deficient mutant of MHV-68 neither prevented tumor formation nor induced hyposplenism. The underlying mechanisms are not known but might be related to an infection-mediated priming of the immune response, resulting in the suppression of a tumor promoting endogenous retrovirus. Thus, under certain circumstances, chronic herpesvirus infection may prevent the development of tumors.
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Affiliation(s)
- S. Raffegerst
- Institute of Molecular Immunology, Helmholtz Zentrum München—German Research Center for Environmental Health (GmbH), Munich, Germany
- * E-mail: (SR); (HA)
| | - B. Steer
- Research Unit Gene Vectors, Helmholtz Zentrum München—German Research Center for Environmental Health (GmbH), Munich, Germany
| | - M. Hohloch
- Institute of Molecular Immunology, Helmholtz Zentrum München—German Research Center for Environmental Health (GmbH), Munich, Germany
| | - H. Adler
- Research Unit Gene Vectors, Helmholtz Zentrum München—German Research Center for Environmental Health (GmbH), Munich, Germany
- * E-mail: (SR); (HA)
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88
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Strick R, Strissel PL, Baylin SB, Chiappinelli KB. Unraveling the molecular pathways of DNA-methylation inhibitors: human endogenous retroviruses induce the innate immune response in tumors. Oncoimmunology 2015; 5:e1122160. [PMID: 27467919 DOI: 10.1080/2162402x.2015.1122160] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 11/17/2015] [Indexed: 10/22/2022] Open
Abstract
Loss of DNA methylation can activate endogenous retroviral expression and dsRNA in cancer cells. This leads to induction of toll-like receptor signaling stimulating an antiviral interferon response. Recent findings provide a therapeutic rationale for combining DNA methylation inhibitors with blockage of immune checkpoint proteins to fight cancer.
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Affiliation(s)
- Reiner Strick
- Department of Gynecology and Obstetrics, Laboratory for Molecular Medicine, Friedrich-Alexander University Erlangen-Nürnberg (FAU), University-Clinic Erlangen , Erlangen, Germany
| | - Pamela L Strissel
- Department of Gynecology and Obstetrics, Laboratory for Molecular Medicine, Friedrich-Alexander University Erlangen-Nürnberg (FAU), University-Clinic Erlangen , Erlangen, Germany
| | - Stephen B Baylin
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins , Baltimore, MD, USA
| | - Katherine B Chiappinelli
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins , Baltimore, MD, USA
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89
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Duran-Struuck R, Matar AJ, Huang CA. Myeloid Leukemias and Virally Induced Lymphomas in Miniature Inbred Swine: Development of a Large Animal Tumor Model. Front Genet 2015; 6:332. [PMID: 26635868 PMCID: PMC4653297 DOI: 10.3389/fgene.2015.00332] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/02/2015] [Indexed: 11/13/2022] Open
Abstract
The lack of a large animal transplantable tumor model has limited the study of novel therapeutic strategies for the treatment of liquid cancers. Swine as a species provide a natural option based on their similarities with humans and their already extensive use in biomedical research. Specifically, the Massachusetts General Hospital miniature swine herd retains unique genetic characteristics that facilitate the study of hematopoietic cell and solid organ transplantation. Spontaneously arising liquid cancers in these swine, specifically myeloid leukemias and B cell lymphomas, closely resemble human malignancies. The ability to establish aggressive tumor cell lines in vitro from these naturally occurring malignancies makes a transplantable tumor model a close reality. Here, we discuss our experience with myeloid and lymphoid tumors in major histocompatibility characterized miniature swine and future approaches regarding the development of a large animal transplantable tumor model.
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Affiliation(s)
- Raimon Duran-Struuck
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia PA, USA
| | - Abraham J Matar
- University of Central Florida College of Medicine, Orlando FL, USA
| | - Christene A Huang
- Center for Transplantation Sciences, Massachusetts General Hospital, Boston MA, USA
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90
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Seya T, Shime H, Takeda Y, Tatematsu M, Takashima K, Matsumoto M. Adjuvant for vaccine immunotherapy of cancer--focusing on Toll-like receptor 2 and 3 agonists for safely enhancing antitumor immunity. Cancer Sci 2015; 106:1659-68. [PMID: 26395101 PMCID: PMC4714660 DOI: 10.1111/cas.12824] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 09/15/2015] [Accepted: 09/17/2015] [Indexed: 12/16/2022] Open
Abstract
Immune‐enhancing adjuvants usually targets antigen (Ag)‐presenting cells to tune up cellular and humoral immunity. CD141+ dendritic cells (DC) represent the professional Ag‐presenting cells in humans. In response to microbial pattern molecules, these DCs upgrade the maturation stage sufficient to improve cross‐presentation of exogenous Ag, and upregulation of MHC and costimulators, allowing CD4/CD8 T cells to proliferate and liberating cytokines/chemokines that support lymphocyte attraction and survival. These DCs also facilitate natural killer‐mediated cell damage. Toll‐like receptors (TLRs) and their signaling pathways in DCs play a pivotal role in DC maturation. Therefore, providing adjuvants in addition to Ag is indispensable for successful vaccine immunotherapy for cancer, which has been approved in comparison with antimicrobial vaccines. Mouse CD8α+DCs express TLR7 and TLR9 in addition to the TLR2 family (TLR1, 2, and 6) and TLR3, whereas human CD141+DCs exclusively express the TLR2 family and TLR3. Although human and mouse plasmacytoid DCs commonly express TLR7/9 to respond to their agonists, the results on mouse adjuvant studies using TLR7/9 agonists cannot be simply extrapolated to human adjuvant immunotherapy. In contrast, TLR2 and TLR3 are similarly expressed in both human and mouse Ag‐presenting DCs. Bacillus Calmette–Guerin peptidoglycan and polyinosinic–polycytidylic acid are representative agonists for TLR2 and TLR3, respectively, although they additionally stimulate cytoplasmic sensors: their functional specificities may not be limited to the relevant TLRs. These adjuvants have been posted up to a certain achievement in immunotherapy in some cancers. We herein summarize the history and perspectives of TLR2 and TLR3 agonists in vaccine‐adjuvant immunotherapy for cancer.
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Affiliation(s)
- Tsukasa Seya
- Department of Microbiology and Immunology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroaki Shime
- Department of Microbiology and Immunology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Yohei Takeda
- Department of Microbiology and Immunology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Megumi Tatematsu
- Department of Microbiology and Immunology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Ken Takashima
- Department of Microbiology and Immunology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Misako Matsumoto
- Department of Microbiology and Immunology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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91
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Suntsova M, Garazha A, Ivanova A, Kaminsky D, Zhavoronkov A, Buzdin A. Molecular functions of human endogenous retroviruses in health and disease. Cell Mol Life Sci 2015; 72:3653-75. [PMID: 26082181 PMCID: PMC11113533 DOI: 10.1007/s00018-015-1947-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 05/29/2015] [Accepted: 06/03/2015] [Indexed: 12/13/2022]
Abstract
Human endogenous retroviruses (HERVs) and related genetic elements form 504 distinct families and occupy ~8% of human genome. Recent success of high-throughput experimental technologies facilitated understanding functional impact of HERVs for molecular machinery of human cells. HERVs encode active retroviral proteins, which may exert important physiological functions in the body, but also may be involved in the progression of cancer and numerous human autoimmune, neurological and infectious diseases. The spectrum of related malignancies includes, but not limits to, multiple sclerosis, psoriasis, lupus, schizophrenia, multiple cancer types and HIV. In addition, HERVs regulate expression of the neighboring host genes and modify genomic regulatory landscape, e.g., by providing regulatory modules like transcription factor binding sites (TFBS). Indeed, recent bioinformatic profiling identified ~110,000 regulatory active HERV elements, which formed at least ~320,000 human TFBS. These and other peculiarities of HERVs might have played an important role in human evolution and speciation. In this paper, we focus on the current progress in understanding of normal and pathological molecular niches of HERVs, on their implications in human evolution, normal physiology and disease. We also review the available databases dealing with various aspects of HERV genetics.
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Affiliation(s)
- Maria Suntsova
- Group for Genomic Regulation of Cell Signaling Systems, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, 117997, Russia.
- Laboratory of Bioinformatics, D. Rogachyov Federal Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, 117198, Russia.
| | - Andrew Garazha
- Group for Genomic Regulation of Cell Signaling Systems, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, 117997, Russia.
- Laboratory of Bioinformatics, D. Rogachyov Federal Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, 117198, Russia.
| | - Alena Ivanova
- Group for Genomic Regulation of Cell Signaling Systems, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, 117997, Russia.
- Pathway Pharmaceuticals, Wan Chai, Hong Kong, Hong Kong SAR.
| | - Dmitry Kaminsky
- Pathway Pharmaceuticals, Wan Chai, Hong Kong, Hong Kong SAR.
| | - Alex Zhavoronkov
- Pathway Pharmaceuticals, Wan Chai, Hong Kong, Hong Kong SAR.
- Department of Translational and Regenerative Medicine, Moscow Institute of Physics and Technology, 9 Institutskiy per., Dolgoprudny, Moscow, 141700, Russia.
| | - Anton Buzdin
- Group for Genomic Regulation of Cell Signaling Systems, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, 117997, Russia.
- Pathway Pharmaceuticals, Wan Chai, Hong Kong, Hong Kong SAR.
- National Research Centre "Kurchatov Institute", Centre for Convergence of Nano-, Bio-, Information and Cognitive Sciences and Technologies, 1, Akademika Kurchatova sq., Moscow, 123182, Russia.
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92
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Beck-Engeser GB, Ahrends T, Knittel G, Wabl R, Metzner M, Eilat D, Wabl M. Infectivity and insertional mutagenesis of endogenous retrovirus in autoimmune NZB and B/W mice. J Gen Virol 2015; 96:3396-3410. [PMID: 26315139 DOI: 10.1099/jgv.0.000271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Murine leukaemia virus has been suggested to contribute to both autoimmune disease and leukaemia in the NZB mouse and in the (NZB × NZW) F1 (abbreviated B/W) mouse. However, with apparently only xenotropic but no ecotropic virus constitutively expressed in these mice, few mechanisms could explain the aetiology of either disease in either mouse strain. Because pseudotyped and/or inducible ecotropic virus may play a role, we surveyed the ability of murine leukaemia virus in NZB, NZW and B/W mice to infect and form a provirus. From the spleen of NZB mice, we isolated circular cDNA of xenotropic and polytropic virus, which indicates ongoing infection by these viruses. From a B/W lymphoma, we isolated and determined the complete sequence of a putative ecotropic NZW virus. From B/W mice, we recovered de novo endogenous retroviral integration sites (tags) from the hyperproliferating cells of the spleen and the peritoneum. The tagged genes seemed to be selected to aid cellular proliferation, as several of them are known cancer genes. The insertions are consistent with the idea that endogenous retrovirus contributes to B-cell hyperproliferation and progression to lymphoma in B/W mice.
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Affiliation(s)
- Gabriele B Beck-Engeser
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143-0414, USA
| | - Tomasz Ahrends
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143-0414, USA
| | - Gero Knittel
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143-0414, USA
| | - Rafael Wabl
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143-0414, USA
| | - Mirjam Metzner
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143-0414, USA
| | - Dan Eilat
- Department of Medicine, Hadassah University Hospital and The Hebrew University Faculty of Medicine, Jerusalem 91120, Israel
| | - Matthias Wabl
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143-0414, USA
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93
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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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94
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Abstract
Nucleic acid sensing by innate receptors initiates immune defences against viruses and other pathogens. A hallmark of this response is the release of interferons (IFNs), which promote protective immunity by inducing IFN-stimulated genes (ISGs). A similar ISG signature is found in autoinflammatory and autoimmune conditions, indicating that chronic activation of nucleic acid-sensing pathways may contribute to these diseases. Here, we review how nucleic acid-sensing pathways are currently being targeted pharmacologically with both agonists and antagonists. We discuss how an improved understanding of the biology of these pathways is leading to novel therapies for infections, cancer, and autoimmune and autoinflammatory disorders, and how new therapeutics will, in turn, generate a deeper understanding of these complex diseases.
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95
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Hematopoietic Stem and Immune Cells in Chronic HIV Infection. Stem Cells Int 2015; 2015:148064. [PMID: 26300920 PMCID: PMC4537765 DOI: 10.1155/2015/148064] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 07/15/2015] [Accepted: 07/21/2015] [Indexed: 02/07/2023] Open
Abstract
Hematopoietic stem cell (HSC) belongs to multipotent adult somatic stem cells. A single HSC can reconstitute the entire blood system via self-renewal, differentiation into all lineages of blood cells, and replenishment of cells lost due to attrition or disease in a person's lifetime. Although all blood and immune cells derive from HSC, immune cells, specifically immune memory cells, have the properties of HSC on self-renewal and differentiation into lineage effector cells responding to the invading pathogens. Moreover, the interplay between immune memory cell and viral pathogen determines the course of a viral infection. Here, we state our point of view on the role of blood stem and progenitor cell in chronic HIV infection, with a focus on memory CD4 T-cell in the context of HIV/AIDS eradication and cure.
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96
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97
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Rooney MS, Shukla SA, Wu CJ, Getz G, Hacohen N. Molecular and genetic properties of tumors associated with local immune cytolytic activity. Cell 2015; 160:48-61. [PMID: 25594174 DOI: 10.1016/j.cell.2014.12.033] [Citation(s) in RCA: 2544] [Impact Index Per Article: 282.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 12/09/2014] [Accepted: 12/24/2014] [Indexed: 02/07/2023]
Abstract
How the genomic landscape of a tumor shapes and is shaped by anti-tumor immunity has not been systematically explored. Using large-scale genomic data sets of solid tissue tumor biopsies, we quantified the cytolytic activity of the local immune infiltrate and identified associated properties across 18 tumor types. The number of predicted MHC Class I-associated neoantigens was correlated with cytolytic activity and was lower than expected in colorectal and other tumors, suggesting immune-mediated elimination. We identified recurrently mutated genes that showed positive association with cytolytic activity, including beta-2-microglobulin (B2M), HLA-A, -B and -C and Caspase 8 (CASP8), highlighting loss of antigen presentation and blockade of extrinsic apoptosis as key strategies of resistance to cytolytic activity. Genetic amplifications were also associated with high cytolytic activity, including immunosuppressive factors such as PDL1/2 and ALOX12B/15B. Our genetic findings thus provide evidence for immunoediting in tumors and uncover mechanisms of tumor-intrinsic resistance to cytolytic activity.
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Affiliation(s)
- Michael S Rooney
- The Broad Institute, Cambridge, MA 02142, USA; Harvard/MIT Division of Health Sciences and Technology, Cambridge, MA 02141, USA
| | - Sachet A Shukla
- The Broad Institute, Cambridge, MA 02142, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Catherine J Wu
- The Broad Institute, Cambridge, MA 02142, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Gad Getz
- The Broad Institute, Cambridge, MA 02142, USA; Massachusetts General Hospital Cancer Center and Department of Pathology, Charlestown, MA 02129, USA
| | - Nir Hacohen
- The Broad Institute, Cambridge, MA 02142, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; Center for Immunology and Inflammatory Diseases and Department of Medicine, Massachusetts General Hospital, Charlestown, MA 02129, USA.
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98
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Guillerey C, Chow MT, Miles K, Olver S, Sceneay J, Takeda K, Möller A, Smyth MJ. Toll-like receptor 3 regulates NK cell responses to cytokines and controls experimental metastasis. Oncoimmunology 2015; 4:e1027468. [PMID: 26405596 DOI: 10.1080/2162402x.2015.1027468] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/28/2015] [Accepted: 03/03/2015] [Indexed: 12/22/2022] Open
Abstract
The Toll-like receptor 3 (TLR3) agonist poly(I:C) is a promising adjuvant for cancer vaccines due to its induction of potent antitumor responses occurring primarily through the activation of dendritic cells (DCs) and natural killer (NK) cells. However, little is known about the role of TLR3 sensing of endogenous ligands in innate tumor immunosurveillance. Here, we investigated whether TLR3 could modulate immune responses and facilitate tumor control without administration of an agonist. We observed only limited impact of TLR3 deficiency on spontaneous carcinogenesis and primary growth of B16F10, E0771 or MC38 tumors when injected subcutaneously to mice. Nevertheless, TLR3 was observed to limit experimental B16F10 lung metastasis, an immunologic constraint dependent on both IFNγ secretion and NK cells. Interestingly, we observed that NK cells derived from Tlr3 null (Tlr3-/- ) mice were hyporesponsive to cytokine stimulation. Indeed, compared with NK cells with intact TLR3, Tlr3-/- NK cells produced significantly reduced pro-inflammatory cytokines, including IFNγ, when incubated in the presence of different combinations of IL-12, IL-18 and IL-15. Bone-marrow chimera experiments established that competent NK cell responses required TLR3 sensing on radio-sensitive immune cells. Intriguingly, although CD8α DCs robustly express high levels of TLR3, we found that those cells were not necessary for efficient IFNγ production by NK cells. Moreover, the defective NK cell phenotype of Tlr3-/- mice appeared to be independent of the gut microbiota. Altogether, our data demonstrate a pivotal role of endogenous TLR3 stimulation for the acquisition of full NK cell functions and immune protection against experimental metastasis.
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Affiliation(s)
- Camille Guillerey
- Immunology of Cancer and Infection Laboratory; QIMR Berghofer Medical Research Institute ; Herston, Queensland, Australia ; School of Medicine; University of Queensland ; Herston, Queensland, Australia
| | - Melvyn T Chow
- Immunology of Cancer and Infection Laboratory; QIMR Berghofer Medical Research Institute ; Herston, Queensland, Australia
| | - Kim Miles
- Immunology of Cancer and Infection Laboratory; QIMR Berghofer Medical Research Institute ; Herston, Queensland, Australia
| | - Stuart Olver
- Bone Marrow Transplantation; QIMR Berghofer Medical Research Institute ; Herston, Queensland, Australia
| | - Jaclyn Sceneay
- Tumour Microenvironment Laboratory; QIMR Berghofer Medical Research Institute ; Herston, Queensland, Australia
| | - Kazuyoshi Takeda
- Department of Immunology; Juntendo University School of Medicine ; Hongo, Tokyo, Japan
| | - Andreas Möller
- School of Medicine; University of Queensland ; Herston, Queensland, Australia ; Tumour Microenvironment Laboratory; QIMR Berghofer Medical Research Institute ; Herston, Queensland, Australia
| | - Mark J Smyth
- Immunology of Cancer and Infection Laboratory; QIMR Berghofer Medical Research Institute ; Herston, Queensland, Australia ; School of Medicine; University of Queensland ; Herston, Queensland, Australia
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99
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Beck-Engeser GB, Winkelmann R, Wheeler ML, Shansab M, Yu P, Wünsche S, Walchhütter A, Metzner M, Vettermann C, Eilat D, DeFranco A, Jäck HM, Wabl M. APOBEC3 enzymes restrict marginal zone B cells. Eur J Immunol 2015; 45:695-704. [PMID: 25501566 PMCID: PMC4972502 DOI: 10.1002/eji.201445218] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 10/31/2014] [Accepted: 12/09/2014] [Indexed: 12/16/2022]
Abstract
In general, a long-lasting immune response to viruses is achieved when they are infectious and replication competent. In the mouse, the neutralizing antibody response to Friend murine leukemia virus is contributed by an allelic form of the enzyme Apobec3 (abbreviated A3). This is counterintuitive because A3 directly controls viremia before the onset of adaptive antiviral immune responses. It suggests that A3 also affects the antibody response directly. Here, we studied the relative size of cell populations of the adaptive immune system as a function of A3 activity. We created a transgenic mouse that expresses all seven human A3 enzymes and compared it to WT and mouse A3-deficient mice. A3 enzymes decreased the number of marginal zone B cells, but not the number of follicular B or T cells. When mouse A3 was knocked out, the retroelement hitchhiker-1 and sialyl transferases encoded by genes close to it were overexpressed three and two orders of magnitude, respectively. We suggest that A3 shifts the balance, from the fast antibody response mediated by marginal zone B cells with little affinity maturation, to a more sustained germinal center B-cell response, which drives affinity maturation and, thereby, a better neutralizing response.
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Affiliation(s)
| | - Rebecca Winkelmann
- Division of Molecular Immunology, Department of Internal Medicine III, Nikolaus-Fiebiger-Center, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Matthew L. Wheeler
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
| | - Maryam Shansab
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
| | - Philipp Yu
- Institut für Immunologie, Philipps-Universität Marburg, Marburg, Germany
| | - Sarah Wünsche
- Institut für Immunologie, Philipps-Universität Marburg, Marburg, Germany
| | - Anja Walchhütter
- Institut für Immunologie, Philipps-Universität Marburg, Marburg, Germany
| | - Mirjam Metzner
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
- Division of Molecular Immunology, Department of Internal Medicine III, Nikolaus-Fiebiger-Center, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Christian Vettermann
- Division of Molecular Immunology, Department of Internal Medicine III, Nikolaus-Fiebiger-Center, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Dan Eilat
- Department of Medicine, Hadassah University Hospital and The Hebrew University Faculty of Medicine, Jerusalem, Israel
| | - Anthony DeFranco
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
| | - Hans-Martin Jäck
- Division of Molecular Immunology, Department of Internal Medicine III, Nikolaus-Fiebiger-Center, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Matthias Wabl
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
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100
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Shimode S, Nakagawa S, Miyazawa T. Multiple invasions of an infectious retrovirus in cat genomes. Sci Rep 2015; 5:8164. [PMID: 25641657 PMCID: PMC4313119 DOI: 10.1038/srep08164] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 01/07/2015] [Indexed: 01/08/2023] Open
Abstract
Endogenous retroviruses (ERVs) are remnants of ancient retroviral infections of host germ-line cells. While most ERVs are defective, some are active and express viral proteins. The RD-114 virus is a replication-competent feline ERV, and several feline cell lines produce infectious RD-114 viral particles. All domestic cats are considered to have an ERV locus encoding a replication-competent RD-114 virus in their genomes; however, the locus has not been identified. In this study, we investigated RD-114 virus-related proviral loci in genomes of domestic cats, and found that none were capable of producing infectious viruses. We also found that all domestic cats have an RD-114 virus-related sequence on chromosome C2, termed RDRS C2a, but populations of the other RDRSs are different depending on the regions where cats live or breed. Our results indicate that RDRS C2a, the oldest RD-114-related provirus, entered the host genome before an ancestor of domestic cats started diverging and the other new RDRSs might have integrated into migrating cats in Europe. We also show that infectious RD-114 virus can be resurrected by the recombination between two non-infectious RDRSs. From these data, we conclude that cats do not harbor infectious RD-114 viral loci in their genomes and RD-114-related viruses invaded cat genomes multiple times.
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Affiliation(s)
- Sayumi Shimode
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8501, Japan
| | - So Nakagawa
- Department of Molecular Life Science, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Takayuki Miyazawa
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8501, Japan
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