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Dow CT, Pierce ES, Sechi LA. Mycobacterium paratuberculosis: A HERV Turn-On for Autoimmunity, Neurodegeneration, and Cancer? Microorganisms 2024; 12:1890. [PMID: 39338563 PMCID: PMC11434025 DOI: 10.3390/microorganisms12091890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Revised: 08/27/2024] [Accepted: 08/30/2024] [Indexed: 09/30/2024] Open
Abstract
Human endogenous retroviruses (HERVs) are remnants of ancient retroviral infections that, over millions of years, became integrated into the human genome. While normally inactive, environmental stimuli such as infections have contributed to the transcriptional reactivation of HERV-promoting pathological conditions, including the development of autoimmunity, neurodegenerative disease and cancer. What infections trigger HERV activation? Mycobacterium avium subspecies paratuberculosis (MAP) is a pluripotent driver of human disease. Aside from granulomatous diseases, Crohn's disease, sarcoidosis and Blau syndrome, MAP is associated with autoimmune disease: type one diabetes (T1D), multiple sclerosis (MS), rheumatoid arthritis (RA) and autoimmune thyroiditis. MAP is also associated with Alzheimer's disease (AD) and Parkinson's disease (PD). Autoimmune diabetes, MS and RA are the diseases with the strongest MAP/HERV association. There are several other diseases associated with HERV activation, including diseases whose epidemiology and/or pathology would prompt speculation for a causal role of MAP. These include non-solar uveal melanoma, colon cancer, glioblastoma and amyotrophic lateral sclerosis (ALS). This article further points to MAP infection as a contributor to autoimmunity, neurodegenerative disease and cancer via the un-silencing of HERV. We examine the link between the ever-increasing number of MAP-associated diseases and the MAP/HERV intersection with these diverse medical conditions, and propose treatment opportunities based upon this association.
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Affiliation(s)
- Coad Thomas Dow
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA
| | | | - Leonardo A. Sechi
- Department of Biomedical Science, University of Sassari, 07100 Sassari, Italy;
- Azienda Ospedaliera Universitaria di Sassari, Viale San Pietro, 07100 Sassari, Italy
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Skandorff I, Gille J, Ragonnaud E, Andersson AM, Schrödel S, Thirion C, Wagner R, Holst PJ. The Insertion of an Evolutionary Lost Four-Amino-Acid Cytoplasmic Tail Peptide into a Syncytin-1 Vaccine Increases T- and B-Cell Responses in Mice. Viruses 2023; 15:1686. [PMID: 37632028 PMCID: PMC10458386 DOI: 10.3390/v15081686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/30/2023] [Accepted: 07/31/2023] [Indexed: 08/27/2023] Open
Abstract
Human endogenous retrovirus type W (HERV-W) is expressed in various cancers. We previously developed an adenovirus-vectored cancer vaccine targeting HERV-W by encoding an assembled HERV-W group-specific antigen sequence and the HERV-W envelope sequence Syncytin-1. Syncytin-1 is constitutively fusogenic and forms large multinucleated cell fusions when overexpressed. Consequently, immunising humans with a vaccine encoding Syncytin-1 can lead to the formation of extensive syncytia, which is undesirable and poses a potential safety issue. Here, we show experiments in cell lines that restoring an evolutionary lost cleavage site of the fusion inhibitory R-peptide of Syncytin-1 inhibit cell fusion. Interestingly, this modification of the HERV-W vaccine's fusogenicity increased the expression of the vaccine antigens in vitro. It also enhanced Syncytin-1-specific antibody responses and CD8+-mediated T-cell responses compared to the wildtype vaccine in vaccinated mice, with a notable enhancement in responses to subdominant T-cell epitopes but equal responses to dominant epitopes and similar rates of survival following a tumour challenge. The impairment of cell-cell fusion and the enhanced immunogenicity profile of this HERV-W vaccine strengthens the prospects of obtaining a meaningful immune response against HERV-W in patients with HERV-W-overexpressing cancers.
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Affiliation(s)
- Isabella Skandorff
- Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark;
- InProTher, COBIS, Ole Maaloesvej 3, 2200 Copenhagen, Denmark; (E.R.); (A.-M.A.)
| | - Jasmin Gille
- Institute of Medical Microbiology and Hygiene, Molecular Microbiology, University of Regensburg Germany, 93053 Regensburg, Germany; (J.G.); (R.W.)
| | - Emeline Ragonnaud
- InProTher, COBIS, Ole Maaloesvej 3, 2200 Copenhagen, Denmark; (E.R.); (A.-M.A.)
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | | | - Silke Schrödel
- Sirion Biotech GmbH, Am Haag 6, 82166 Graefelfing, Germany; (S.S.); (C.T.)
| | - Christian Thirion
- Sirion Biotech GmbH, Am Haag 6, 82166 Graefelfing, Germany; (S.S.); (C.T.)
| | - Ralf Wagner
- Institute of Medical Microbiology and Hygiene, Molecular Microbiology, University of Regensburg Germany, 93053 Regensburg, Germany; (J.G.); (R.W.)
| | - Peter Johannes Holst
- InProTher, COBIS, Ole Maaloesvej 3, 2200 Copenhagen, Denmark; (E.R.); (A.-M.A.)
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
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3
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Skandorff I, Ragonnaud E, Gille J, Andersson AM, Schrödel S, Duvnjak L, Turner L, Thirion C, Wagner R, Holst PJ. Human Ad19a/64 HERV-W Vaccines Uncover Immunosuppression Domain-Dependent T-Cell Response Differences in Inbred Mice. Int J Mol Sci 2023; 24:9972. [PMID: 37373123 DOI: 10.3390/ijms24129972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/06/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
Expression of human endogenous retrovirus type W (HERV-W) has been linked to cancer, making HERV-W antigens potential targets for therapeutic cancer vaccines. In a previous study, we effectively treated established tumours in mice by using adenoviral-vectored vaccines targeting the murine endogenous retrovirus envelope and group-specific antigen (Gag) of melanoma-associated retrovirus (MelARV) in combination with anti-PD-1. To break the immunological tolerance to MelARV, we mutated the immunosuppressive domain (ISD) of the MelARV envelope. However, reports on the immunogenicity of the HERV-W envelope, Syncytin-1, and its ISD are conflicting. To identify the most effective HERV-W cancer vaccine candidate, we evaluated the immunogenicity of vaccines encoding either the wild-type or mutated HERV-W envelope ISD in vitro and in vivo. Here, we show that the wild-type HERV-W vaccine generated higher activation of murine antigen-presenting cells and higher specific T-cell responses than the ISD-mutated counterpart. We also found that the wild-type HERV-W vaccine was sufficient to increase the probability of survival in mice subjected to HERV-W envelope-expressing tumours compared to a control vaccine. These findings provide the foundation for developing a therapeutic cancer vaccine targeting HERV-W-positive cancers in humans.
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Affiliation(s)
- Isabella Skandorff
- Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
- InProTher, COBIS, Ole Maaloesvej 3, 2200 Copenhagen, Denmark
| | - Emeline Ragonnaud
- InProTher, COBIS, Ole Maaloesvej 3, 2200 Copenhagen, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Jasmin Gille
- Institute of Medical Microbiology and Hygiene, Molecular Microbiology, University of Regensburg, 93053 Regensburg, Germany
| | | | - Silke Schrödel
- Sirion Biotech GmbH, Am Haag 6, 82166 Graefelfing, Germany
| | - Lara Duvnjak
- Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
- InProTher, COBIS, Ole Maaloesvej 3, 2200 Copenhagen, Denmark
| | - Louise Turner
- Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | | | - Ralf Wagner
- Institute of Medical Microbiology and Hygiene, Molecular Microbiology, University of Regensburg, 93053 Regensburg, Germany
| | - Peter Johannes Holst
- InProTher, COBIS, Ole Maaloesvej 3, 2200 Copenhagen, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
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4
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Bello-Morales R, Andreu S, Ripa I, López-Guerrero JA. HSV-1 and Endogenous Retroviruses as Risk Factors in Demyelination. Int J Mol Sci 2021; 22:ijms22115738. [PMID: 34072259 PMCID: PMC8199333 DOI: 10.3390/ijms22115738] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 12/19/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1) is a neurotropic alphaherpesvirus that can infect the peripheral and central nervous systems, and it has been implicated in demyelinating and neurodegenerative processes. Transposable elements (TEs) are DNA sequences that can move from one genomic location to another. TEs have been linked to several diseases affecting the central nervous system (CNS), including multiple sclerosis (MS), a demyelinating disease of unknown etiology influenced by genetic and environmental factors. Exogenous viral transactivators may activate certain retrotransposons or class I TEs. In this context, several herpesviruses have been linked to MS, and one of them, HSV-1, might act as a risk factor by mediating processes such as molecular mimicry, remyelination, and activity of endogenous retroviruses (ERVs). Several herpesviruses have been involved in the regulation of human ERVs (HERVs), and HSV-1 in particular can modulate HERVs in cells involved in MS pathogenesis. This review exposes current knowledge about the relationship between HSV-1 and human ERVs, focusing on their contribution as a risk factor for MS.
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Affiliation(s)
- Raquel Bello-Morales
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (I.R.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
- Correspondence:
| | - Sabina Andreu
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (I.R.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
| | - Inés Ripa
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (I.R.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
| | - José Antonio López-Guerrero
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (I.R.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
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Human Endogenous Retrovirus as Therapeutic Targets in Neurologic Disease. Pharmaceuticals (Basel) 2021; 14:ph14060495. [PMID: 34073730 PMCID: PMC8225122 DOI: 10.3390/ph14060495] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/15/2021] [Accepted: 05/17/2021] [Indexed: 01/16/2023] Open
Abstract
Human endogenous retroviruses (HERVs) are ancient retroviral DNA sequences established into germline. They contain regulatory elements and encoded proteins few of which may provide benefits to hosts when co-opted as cellular genes. Their tight regulation is mainly achieved by epigenetic mechanisms, which can be altered by environmental factors, e.g., viral infections, leading to HERV activation. The aberrant expression of HERVs associates with neurological diseases, such as multiple sclerosis (MS) or amyotrophic lateral sclerosis (ALS), inflammatory processes and neurodegeneration. This review summarizes the recent advances on the epigenetic mechanisms controlling HERV expression and the pathogenic effects triggered by HERV de-repression. This article ends by describing new, promising therapies, targeting HERV elements, one of which, temelimab, has completed phase II trials with encouraging results in treating MS. The information gathered here may turn helpful in the design of new strategies to unveil epigenetic failures behind HERV-triggered diseases, opening new possibilities for druggable targets and/or for extending the use of temelimab to treat other associated diseases.
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Garcia-Montojo M, Nath A. HERV-W envelope expression in blood leukocytes as a marker of disease severity of COVID-19. EBioMedicine 2021; 67:103363. [PMID: 33993053 PMCID: PMC8116818 DOI: 10.1016/j.ebiom.2021.103363] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 04/13/2021] [Indexed: 11/23/2022] Open
Affiliation(s)
- Marta Garcia-Montojo
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Avindra Nath
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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7
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Fu Y, Zhuang X, Xia X, Li X, Xiao K, Liu X. Correlation Between Promoter Hypomethylation and Increased Expression of Syncytin-1 in Non-Small Cell Lung Cancer. Int J Gen Med 2021; 14:957-965. [PMID: 33776474 PMCID: PMC7989540 DOI: 10.2147/ijgm.s294392] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 02/19/2021] [Indexed: 12/15/2022] Open
Abstract
Introduction Syncytin-1 is a human endogenous retroviral (HERVW) envelope protein, which has been implicated in trophoblast and cancer cell fusions as well as in immunomodulatory functions. We investigated syncytin-1 expression and promoter methylation in non-small cell lung cancer (NSCLC) and the adjacent, para-carcinoma tissues. In addition, the correlation to patient survival differentiation of between 5-year survival and death group was analyzed. Methods Survival ratio was calculated by Kaplan-Meier survival curve. Death risk assessment was executed by Cox risk regression model. The 5ʹ-LTR methylation level of HERVW promoter was detected by EpiTYPER method. Results Syncytin-1 expression in NSCLC tissue was found to be significantly higher than in para-carcinoma tissues. Moreover, the 5-year survival group has a lower syncytin-1 expression than the death group. Clinical stage and the percentage of syncytin-1 positive cells were top risk factors according to Cox ratio risk regression model analysis. While the methylation level of the 5ʹ-LTR in HERVW gene promoter was relatively lower in NSCLC than para-carcinoma tissues, the methylation status of a CpG-2 site overlapping the Oct-1 binding site was found to be an important element potentially involved in the epigenetic regulation of HERVW gene expression. Conclusion These findings suggest that syncytin-1 could be a biomarker for the diagnosis/prognosis of NSCLC, and further studies are required to elucidate the exact role of syncytin-1 in the development of NSCLC as well as the underlying molecular mechanism for syncytin-1 function and regulation.
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Affiliation(s)
- Yang Fu
- Department of Reproductive Medicine Center, Jinan Maternity and Child Care Hospital, Jinan, 250001, People's Republic of China
| | - Xuewei Zhuang
- Department of Clinical Laboratory Medicine, Shandong Provincial Third Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250031, People's Republic of China.,Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, People's Republic of China
| | - Xiyan Xia
- Department of Microbial Immune, Jinan Vocational College of Nursing, Jinan, 250012, People's Republic of China
| | - Xiaohui Li
- Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, People's Republic of China
| | - Ke Xiao
- Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, People's Republic of China
| | - Xiaojing Liu
- Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, People's Republic of China
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The Relationship of the Mechanisms of the Pathogenesis of Multiple Sclerosis and the Expression of Endogenous Retroviruses. BIOLOGY 2020; 9:biology9120464. [PMID: 33322628 PMCID: PMC7764762 DOI: 10.3390/biology9120464] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/07/2020] [Accepted: 12/10/2020] [Indexed: 12/16/2022]
Abstract
Simple Summary Multiple sclerosis is a neurodegenerative disease of the central nervous system, develops at an early age and often leads to a disability. The etiological cause of the disease has not been fully elucidated, and as a result, no effective treatment is available. This review summarizes the current knowledge about the relationship between the expression of human endogenous retroviruses and the pathogenesis of multiple sclerosis. The epigenetic mechanisms of transcriptional regulation, the role of transcription factors, cytokines, and exogenous viruses are also addressed in this review. The elucidation of the mechanisms of an increase in endogenous retrovirus expression in multiple sclerosis could help to develop therapeutic strategies and novel methods for early diagnosis and treatment of the disease. Abstract Two human endogenous retroviruses of the HERV-W family can act as cofactors triggering multiple sclerosis (MS): MS-associated retrovirus (MSRV) and ERVWE1. Endogenous retroviral elements are believed to have integrated in our ancestors’ DNA millions of years ago. Their involvement in the pathogenesis of various diseases, including neurodegenerative pathologies, has been demonstrated. Numerous studies have shown a correlation between the deterioration of patients’ health and increased expression of endogenous retroviruses. The exact causes and mechanisms of endogenous retroviruses activation remains unknown, which hampers development of therapeutics. In this review, we will summarize the main characteristics of human endogenous W retroviruses and describe the putative mechanisms of activation, including epigenetic mechanisms, humoral factors as well as the role of the exogenous viral infections.
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Guo L, Gu F, Xu Y, Zhou C. Increased copy number of syncytin-1 in the trophectoderm is associated with implantation of the blastocyst. PeerJ 2020; 8:e10368. [PMID: 33240670 PMCID: PMC7678462 DOI: 10.7717/peerj.10368] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 10/25/2020] [Indexed: 12/19/2022] Open
Abstract
Background A key step in embryo implantation is the adhesion to and invasion of the endometrium by the blastocyst trophectoderm. The envelope proteins of HERV-W and -FRD (human endogenous retrovirus-W and -FRD), syncytin-1 and syncytin-2, are mainly distributed in the placenta, and play important roles in the development of the placenta. The placenta originates from the trophectoderm of the blastocyst. It is unclear whether the envelope proteins of HERV-W and -FRD have an effect on the development of the trophectoderm and whether they have any association with the implantation of the blastocyst. Methods The whole-genome amplification products of the human blastocyst trophectoderm were used to measure the copy number of syncytin-1 and syncytin-2 using real time qPCR. In addition, clinical data associated with the outcome of pregnancies was collected, and included age, body mass index (BMI), basic follicle stimulating hormone(bFSH), rate of primary infertility and oligo-astheno-teratospermia, the thickness of the endometrium on the day of endometrial transformation, the levels of estrogen and progestin on the transfer day, the days and the morphological scores of the blastocysts. The expression of mRNA and the copy numbers of syncytin-1 and syncytin-2 in H1 stem cells, and in differentiated H1 cells, induced by BMP4, were measured using real time qPCR. Results The relative copy number of syncytin-1 in the pregnant group (median: 424%, quartile: 232%-463%, p < 0.05) was significantly higher than in the non-pregnant group (median: 100%, quartile: 81%-163%). There was a correlation (r s = 0.681, p < 0.001) between the copy number of syncytin-1 and blastocyst implantation after embryo transfer. As the stem cells differentiated, the expression of NANOG mRNA decreased, and the expression of caudal type homeobox 2(CDX2) and β-human chorionic gonadotropin (β-hCG) mRNAs increased. Compared to the undifferentiated cells, the relative expression of the syncytin-1 mRNA was 1.63 (quartile: 0.59-6.37, p > 0.05), 3.36 (quartile: 0.85-14.80, p > 0.05), 10.85 (quartile: 3.39-24.46, p < 0.05) and 67.81 (quartile: 54.07-85.48, p < 0.05) on day 1, 3, 5 and 7, respectively, after the differentiation. The relative expression of syncytin-2 was 5.34 (quartile: 4.50-10.30), 7.90 (quartile: 2.46-14.01), 57.44 (quartile: 38.35-103.87) and 344.76 (quartile: 267.72-440.10) on day 1, 3, 5 and 7, respectively, after the differentiation (p < 0.05). The copy number of syncytin-1 increased significantly during differentiation. Conclusion Preceding the transfer of frozen embryos, the increased copy number of syncytin-1 in the blastocyst trophectoderm was associated with good outcomes of pregnancies.
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Affiliation(s)
- Luyan Guo
- Department of Obstetrics and Gynecology, Sun Yat-Sen University First Affiliated Hospital, Guangzhou, Guangdong, China
| | - Fang Gu
- Reproductive Medical Center, Department of Obstetrics and Gynecology, Sun Yat-Sen University First Affiliated Hospital, Guangzhou, Guangdong, China
| | - Yan Xu
- Reproductive Medical Center, Department of Obstetrics and Gynecology, Sun Yat-Sen University First Affiliated Hospital, Guangzhou, Guangdong, China
| | - Canquan Zhou
- Reproductive Medical Center, Department of Obstetrics and Gynecology, Sun Yat-Sen University First Affiliated Hospital, Guangzhou, Guangdong, China.,Key Laboratory of Reproductive Medicine of Guangdong Province, Guangzhou, Guangdong, China
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10
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Garcia-Montojo M, Rodriguez-Martin E, Ramos-Mozo P, Ortega-Madueño I, Dominguez-Mozo MI, Arias-Leal A, García-Martínez MÁ, Casanova I, Galan V, Arroyo R, Álvarez-Lafuente R, Villar LM. Syncytin-1/HERV-W envelope is an early activation marker of leukocytes and is upregulated in multiple sclerosis patients. Eur J Immunol 2020; 50:685-694. [PMID: 32012247 DOI: 10.1002/eji.201948423] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/20/2019] [Accepted: 01/30/2020] [Indexed: 12/22/2022]
Abstract
Syncytin-1 is the envelope protein of the human endogenous retrovirus W (HERV-W). It has been related to multiple sclerosis (MS) but its role in cellular immunity and its pathogenic mechanism in the autoimmune context are not fully understood. We analyzed syncytin-1 levels in peripheral blood mononuclear cells (PBMC) subsets from healthy donors, MS patients in relapse or remission, and patients with acute infections by flow cytometry. PBMC cultures were also prepared to analyze protein expression kinetics. MS patients had higher levels of syncytin-1 levels than controls. We found that syncytin-1 is elevated in monocytes during MS relapses and infections. Cells expressing syncytin-1, including monocytes, T and B lymphocytes, and NKs presented mainly an activated phenotype and, upon stimulation with LPS, its levels increased rapidly on antigen-presenting cells. Syncytin-1 ligation promoted the activation of monocytes, as demonstrated by the upregulation of CD80 and the nonclassical subset CD14low CD16+ . Our results suggest an important role for syncytin-1 in the activation of leukocytes. Given that the expression of syncytin-1 is upregulated in MS patients, this protein might be contributing to the autoimmune cascade in the disease.
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Affiliation(s)
- Marta Garcia-Montojo
- Department of Immunology, Ramón y Cajal University Hospital, Institute Ramon y Cajal for Biomedical Research, Madrid, Spain.,Multiple Sclerosis Unit, Hospital Clinico San Carlos, Institute Clinico San Carlos for Biomedical Research, Madrid, Spain
| | - Eulalia Rodriguez-Martin
- Department of Immunology, Ramón y Cajal University Hospital, Institute Ramon y Cajal for Biomedical Research, Madrid, Spain
| | - Priscila Ramos-Mozo
- Department of Immunology, Hospital Clinico San Carlos, Institute Clinico San Carlos for Biomedical Research, Madrid, Spain
| | - Isabel Ortega-Madueño
- Multiple Sclerosis Unit, Hospital Clinico San Carlos, Institute Clinico San Carlos for Biomedical Research, Madrid, Spain
| | | | - Ana Arias-Leal
- Multiple Sclerosis Unit, Hospital Clinico San Carlos, Institute Clinico San Carlos for Biomedical Research, Madrid, Spain
| | - Maria Ángel García-Martínez
- Department of Immunology, Hospital Clinico San Carlos, Institute Clinico San Carlos for Biomedical Research, Madrid, Spain
| | - Ignacio Casanova
- Multiple Sclerosis Unit, Hospital Clinico San Carlos, Institute Clinico San Carlos for Biomedical Research, Madrid, Spain
| | - Victoria Galan
- Multiple Sclerosis Unit, Hospital Clinico San Carlos, Institute Clinico San Carlos for Biomedical Research, Madrid, Spain
| | - Rafael Arroyo
- Multiple Sclerosis Unit, Hospital Clinico San Carlos, Institute Clinico San Carlos for Biomedical Research, Madrid, Spain
| | - Roberto Álvarez-Lafuente
- Multiple Sclerosis Unit, Hospital Clinico San Carlos, Institute Clinico San Carlos for Biomedical Research, Madrid, Spain
| | - Luisa María Villar
- Department of Immunology, Ramón y Cajal University Hospital, Institute Ramon y Cajal for Biomedical Research, Madrid, Spain
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Li F, Sabunciyan S, Yolken RH, Lee D, Kim S, Karlsson H. Transcription of human endogenous retroviruses in human brain by RNA-seq analysis. PLoS One 2019; 14:e0207353. [PMID: 30605476 PMCID: PMC6317784 DOI: 10.1371/journal.pone.0207353] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 10/30/2018] [Indexed: 01/01/2023] Open
Abstract
Background Human endogenous retroviruses (HERV) comprise 8% of the human genome and can be classified into at least 31 families. Increased levels of transcripts from the W and H families of HERV have been observed in association with human diseases, such as multiple sclerosis and schizophrenia. Although HERV transcripts have been detected in many tissues and cell-types based on microarray and PCR studies, the extent of HERV expression in different cell-types and diseases state has been less comprehensively studied. Results We examined overall transcription of HERV, and particularly of HERV-W and HERV-H elements in human postmortem brain samples obtained from individuals with psychiatric diagnoses (n = 111) and healthy controls (n = 51) by analyzing publicly available RNA sequencing datasets. Sequence reads were aligned to prototypical sequences representing HERV, downloaded from Repbase. We reported a consistent expression (0.1~0.2% of mappable reads) of different HERV families across three regions of human brains. Spearman correlations revealed highly correlated expression levels between three brain regionsacross 475 consensus sequences. By mapping sequences that aligned to the consensus sequences of HERV-W and HERV-H families to individual loci on chromosome 7, more than 60 loci from each family were identified, part of which are being transcribed. The ERVWE1, locus located at chr7q21.2, exhibited high levels of transcription across the three datasets. Notably, we demonstrated a trend of increased expression of overall HERV, as well as HERV-W family in samples from both schizophrenia and bipolar disorder patients. Conclusions The current analyses indicate that RNA sequencing is a useful approach for investigating global expression of repetitive elements, such as HERV, in the human genome. HERV-W/H with the tendency of transcription up-regulation in patients suggests potential implication of HERV-W/H in psychiatric diseases.
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MESH Headings
- Bipolar Disorder/genetics
- Bipolar Disorder/virology
- Brain/metabolism
- Brain/virology
- Chromosomes, Human, Pair 7/genetics
- Depression/genetics
- Depression/virology
- Endogenous Retroviruses/genetics
- Gene Expression Regulation, Viral
- Genetic Loci
- Genome, Human
- Humans
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Repetitive Sequences, Nucleic Acid/genetics
- Schizophrenia/genetics
- Schizophrenia/virology
- Sequence Analysis, RNA
- Statistics, Nonparametric
- Transcription, Genetic
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Affiliation(s)
- Fang Li
- The Center for Heart Development, Key Lab of MOE for Development Biology and Protein Chemistry, College of Life Sciences, Hunan Normal University, Changsha, Hunan, China
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- * E-mail: (FL); (HK)
| | - Sarven Sabunciyan
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Robert H. Yolken
- Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Doheon Lee
- Department of Bio and Brain Engineering, KAIST, Daejeon, Korea
| | - Sanghyeon Kim
- Stanley Medical Research Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Håkan Karlsson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- * E-mail: (FL); (HK)
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12
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Grandi N, Cadeddu M, Blomberg J, Mayer J, Tramontano E. HERV-W group evolutionary history in non-human primates: characterization of ERV-W orthologs in Catarrhini and related ERV groups in Platyrrhini. BMC Evol Biol 2018; 18:6. [PMID: 29351742 PMCID: PMC5775608 DOI: 10.1186/s12862-018-1125-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 01/14/2018] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND The genomes of all vertebrates harbor remnants of ancient retroviral infections, having affected the germ line cells during the last 100 million years. These sequences, named Endogenous Retroviruses (ERVs), have been transmitted to the offspring in a Mendelian way, being relatively stable components of the host genome even long after their exogenous counterparts went extinct. Among human ERVs (HERVs), the HERV-W group is of particular interest for our physiology and pathology. A HERV-W provirus in locus 7q21.2 has been coopted during evolution to exert an essential role in placenta, and the group expression has been tentatively linked to Multiple Sclerosis and other diseases. Following up on a detailed analysis of 213 HERV-W insertions in the human genome, we now investigated the ERV-W group genomic spread within primate lineages. RESULTS We analyzed HERV-W orthologous loci in the genome sequences of 12 non-human primate species belonging to Simiiformes (parvorders Catarrhini and Platyrrhini), Tarsiiformes and to the most primitive Prosimians. Analysis of HERV-W orthologous loci in non-human Catarrhini primates revealed species-specific insertions in the genomes of Chimpanzee (3), Gorilla (4), Orangutan (6), Gibbon (2) and especially Rhesus Macaque (66). Such sequences were acquired in a retroviral fashion and, in the majority of cases, by L1-mediated formation of processed pseudogenes. There were also a number of LTR-LTR homologous recombination events that occurred subsequent to separation of Catarrhini sub-lineages. Moreover, we retrieved 130 sequences in Marmoset and Squirrel Monkeys (family Cebidae, Platyrrhini parvorder), identified as ERV1-1_CJa based on RepBase annotations, which appear closely related to the ERV-W group. Such sequences were also identified in Atelidae and Pitheciidae, representative of the other Platyrrhini families. In contrast, no ERV-W-related sequences were found in genome sequence assemblies of Tarsiiformes and Prosimians. CONCLUSIONS Overall, our analysis now provides a detailed picture of the ERV-W sequences colonization of the primate lineages genomes, revealing the exact dynamics of ERV-W locus formations as well as novel insights into the evolution and origin of the group.
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Affiliation(s)
- Nicole Grandi
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
| | - Marta Cadeddu
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
| | - Jonas Blomberg
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Jens Mayer
- Institute of Human Genetics, University of Saarland, Homburg, Germany
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
- Istituto di Ricerca Genetica e Biomedica (IRGB), CNR, Monserrato, Italy
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13
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Wang X, Huang J, Zhu F. Human Endogenous Retroviral Envelope Protein Syncytin-1 and Inflammatory Abnormalities in Neuropsychological Diseases. Front Psychiatry 2018; 9:422. [PMID: 30245643 PMCID: PMC6137383 DOI: 10.3389/fpsyt.2018.00422] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/17/2018] [Indexed: 12/16/2022] Open
Abstract
Human endogenous retroviruses (HERVs) comprise approximately 8% of the human genome. Recent studies have considered HERVs as potential pathogenic factors. The majority of HERV genes are mutated and not capable of encoding functional proteins; regardless, some HERV genes, such as HERV-W envelope (env) glycoprotein, are known to have intact open reading frames. The HERV-W element on 7q21.2, which encodes a protein referred to as Syncytin-1, participates in human placental morphogenesis and can activate a pro-inflammatory and autoimmune cascade. Neuropsychological disorders are typically linked to inflammatory abnormalities. In this study, we review that Syncytin-1 has been increasingly involved in the development of neuropsychological disorders, such as schizophrenia and multiple sclerosis (MS). This study also presents inflammation imbalances in schizophrenia and MS. More importantly, we discuss the potential role and molecular mechanisms by which Syncytin-1 regulates inflammatory abnormalities in neuropsychological diseases. In summary, Syncytin-1 activity may represent a novel molecular pathogenic mechanism in neuropyschological diseases, such as schizophrenia and MS.
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Affiliation(s)
- Xiuling Wang
- Department of Medical Microbiology, School of Medicine Wuhan University, Wuhan, China.,Department of Medical Laboratory, The Central Hospital of Wuhan Huazhong University of Science and Technology, Wuhan, China
| | - Jin Huang
- Key Laboratory for Molecular Diagnosis of Hubei Province, The Central Hospital of Wuhan Huazhong University of Science and Technology, Wuhan, China
| | - Fan Zhu
- Department of Medical Microbiology, School of Medicine Wuhan University, Wuhan, China.,Hubei Province Key Laboratory of Allergy and Immunology Wuhan University, Wuhan, China
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14
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Grandi N, Tramontano E. Type W Human Endogenous Retrovirus (HERV-W) Integrations and Their Mobilization by L1 Machinery: Contribution to the Human Transcriptome and Impact on the Host Physiopathology. Viruses 2017; 9:v9070162. [PMID: 28653997 PMCID: PMC5537654 DOI: 10.3390/v9070162] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 06/08/2017] [Accepted: 06/20/2017] [Indexed: 01/07/2023] Open
Abstract
Human Endogenous Retroviruses (HERVs) are ancient infection relics constituting ~8% of our DNA. While HERVs’ genomic characterization is still ongoing, impressive amounts of data have been obtained regarding their general expression across tissues. Among HERVs, one of the most studied is the W group, which is the sole HERV group specifically mobilized by the long interspersed element-1 (LINE-1) machinery, providing a source of novel insertions by retrotransposition of HERV-W processed pseudogenes, and comprising a member encoding a functional envelope protein coopted for human placentation. The HERV-W group has been intensively investigated for its putative role in several diseases, such as cancer, inflammation, and autoimmunity. Despite major interest in the link between HERV-W expression and human pathogenesis, no conclusive correlation has been demonstrated so far. In general, (i) the absence of a proper identification of the specific HERV-W sequences expressed in a given condition; and (ii) the lack of studies attempting to connect the various observations in the same experimental conditions are the major problems preventing the definitive assessment of the HERV-W impact on human physiopathology. In this review, we summarize the current knowledge on the HERV-W group presence within the human genome and its expression in physiological tissues as well as in the main pathological contexts.
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Affiliation(s)
- Nicole Grandi
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato SS554, 09042 Monserrato, Cagliari, Italy.
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato SS554, 09042 Monserrato, Cagliari, Italy.
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche (CNR), 09042 Monserrato, Cagliari, Italy.
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15
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Ellul P, Groc L, Leboyer M. [Implication of human endogenous retroviruses in schizophrenia and bipolar disorder]. Med Sci (Paris) 2017; 33:404-409. [PMID: 28497736 DOI: 10.1051/medsci/20173304010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Schizophrenia and bipolar disorder are neuropsychiatric disorders of unknown origin. It seems that these two disorders share some common etiopathogenic mechanisms including genetic, environmental and inflammatory ones. Reactivation of the human endogenous retrovirus type W (HERV-W) can be a shared element in the pathophysiology of schizophrenia and bipolar disorder, linked to immuno-genetic and environment risk factors. We will present studies that have highlighted the presence of HERV-W in schizophrenic and bipolar disorder patients. We will then describe a two-hit model which could explain the common pathophysiological mechanism of affective and non-affective psychosis. Identification of immuno-inflammatory mediated subgroup of schizophrenia and bipolar disorder associated to HERV-W reactivation might open the way for the development of diagnostic biomarker and more targeted treatments. These new tools pave the way towards personalized psychiatry for a better care of patients.
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Affiliation(s)
- Pierre Ellul
- Pôle psychiatrie des hôpitaux universitaires Henri Mondor, AP-HP, université Paris-Est, DHU PePSY, hôpital Albert Chenevier, 40, rue de Mesly, 94000 Créteil, France - Inserm U955, équipe 15, psychiatrie translationnelle, 94000 Créteil, France - Fondation FondaMental, 94000 Créteil, France
| | - Laurent Groc
- Institut interdisciplinaire de neuroscience, CNRS UMR 5297, Université de Bordeaux, 33076 Bordeaux, France - Fondation FondaMental, 94000 Créteil, France
| | - Marion Leboyer
- Pôle psychiatrie des hôpitaux universitaires Henri Mondor, AP-HP, université Paris-Est, DHU PePSY, hôpital Albert Chenevier, 40, rue de Mesly, 94000 Créteil, France - Inserm U955, équipe 15, psychiatrie translationnelle, 94000 Créteil, France - Fondation FondaMental, 94000 Créteil, France
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16
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Ma Y, Liu R, Lv H, Han J, Zhong D, Zhang X. A computational method for prediction of matrix proteins in endogenous retroviruses. PLoS One 2017; 12:e0176909. [PMID: 28472185 PMCID: PMC5417524 DOI: 10.1371/journal.pone.0176909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 04/19/2017] [Indexed: 11/18/2022] Open
Abstract
Human endogenous retroviruses (HERVs) encode active retroviral proteins, which may be involved in the progression of cancer and other diseases. Matrix protein (MA), in group-specific antigen genes (gag) of retroviruses, is associated with the virus envelope glycoproteins in most mammalian retroviruses and may be involved in virus particle assembly, transport and budding. However, the amount of annotated MAs in ERVs is still at a low level so far. No computational method to predict the exact start and end coordinates of MAs in gags has been proposed yet. In this paper, a computational method to identify MAs in ERVs is proposed. A divide and conquer technique was designed and applied to the conventional prediction model to acquire better results when dealing with gene sequences with various lengths. Initiation sites and termination sites were predicted separately and then combined according to their intervals. Three different algorithms were applied and compared: weighted support vector machine (WSVM), weighted extreme learning machine (WELM) and random forest (RF). G − mean (geometric mean of sensitivity and specificity) values of initiation sites and termination sites under 5-fold cross validation generated by random forest models are 0.9869 and 0.9755 respectively, highest among the algorithms applied. Our prediction models combine RF & WSVM algorithms to achieve the best prediction results. 98.4% of all the collected ERV sequences with complete MAs (125 in total) could be predicted exactly correct by the models. 94,671 HERV sequences from 118 families were scanned by the model, 104 new putative MAs were predicted in human chromosomes. Distributions of the putative MAs and optimizations of model parameters were also analyzed. The usage of our predicting method was also expanded to other retroviruses and satisfying results were acquired.
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Affiliation(s)
- Yucheng Ma
- School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an, China
| | - Ruiling Liu
- School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an, China
- * E-mail: (RLL); (HQL)
| | - Hongqiang Lv
- School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an, China
- * E-mail: (RLL); (HQL)
| | - Jiuqiang Han
- School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an, China
| | - Dexing Zhong
- School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an, China
| | - Xinman Zhang
- School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an, China
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17
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Contribution of Syncytins and Other Endogenous Retroviral Envelopes to Human Placenta Pathologies. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 145:111-162. [DOI: 10.1016/bs.pmbts.2016.12.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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18
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Grandi N, Cadeddu M, Blomberg J, Tramontano E. Contribution of type W human endogenous retroviruses to the human genome: characterization of HERV-W proviral insertions and processed pseudogenes. Retrovirology 2016; 13:67. [PMID: 27613107 PMCID: PMC5016936 DOI: 10.1186/s12977-016-0301-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 08/23/2016] [Indexed: 12/21/2022] Open
Abstract
Background Human endogenous retroviruses (HERVs) are ancient sequences integrated in the germ line cells and vertically transmitted through the offspring constituting about 8 % of our genome. In time, HERVs accumulated mutations that compromised their coding capacity. A prominent exception is HERV-W locus 7q21.2, producing a functional Env protein (Syncytin-1) coopted for placental syncytiotrophoblast formation. While expression of HERV-W sequences has been investigated for their correlation to disease, an exhaustive description of the group composition and characteristics is still not available and current HERV-W group information derive from studies published a few years ago that, of course, used the rough assemblies of the human genome available at that time. This hampers the comparison and correlation with current human genome assemblies. Results In the present work we identified and described in detail the distribution and genetic composition of 213 HERV-W elements. The bioinformatics analysis led to the characterization of several previously unreported features and provided a phylogenetic classification of two main subgroups with different age and structural characteristics. New facts on HERV-W genomic context of insertion and co-localization with sequences putatively involved in disease development are also reported. Conclusions The present work is a detailed overview of the HERV-W contribution to the human genome and provides a robust genetic background useful to clarify HERV-W role in pathologies with poorly understood etiology, representing, to our knowledge, the most complete and exhaustive HERV-W dataset up to date. Electronic supplementary material The online version of this article (doi:10.1186/s12977-016-0301-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nicole Grandi
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato SS554, 09042, Monserrato, Cagliari, Italy
| | - Marta Cadeddu
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato SS554, 09042, Monserrato, Cagliari, Italy
| | - Jonas Blomberg
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato SS554, 09042, Monserrato, Cagliari, Italy. .,Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche (CNR), Monserrato, Cagliari, Italy.
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19
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Li F, Karlsson H. Expression and regulation of human endogenous retrovirus W elements. APMIS 2016; 124:52-66. [PMID: 26818262 DOI: 10.1111/apm.12478] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 10/12/2015] [Indexed: 01/06/2023]
Abstract
Human endogenous retroviruses (HERV) comprise 8% of the human genome and can be classified into at least 31 families. A typical HERV provirus consists of internal gag, pol and env genes, flanked by two long terminal repeats (LTRs). No single provirus is capable of engendering infectious particles. HERV are by nature repetitive and have with few notable exceptions lost their protein-coding capacity. Therefore, HERV have consistently been excluded from array-based expression studies and hence little is known of their expression, regulation, and potential functional significance. An increasing number of studies have, however, observed expression of the W family of HERV in various human tissues and cells, predominantly in placenta. HERV-W LTRs act as promoters in directing transcription of HERV-W members, contribute to their tissue-specific and highly diversified expression pattern. Furthermore, leaky transcription originating from adjacent genes plays a role in the transcription initiation of HERV-W psudoelements. It has been reported that HERV-W elements, including ERVWE1 (the so far only known HERV-W locus harboring a gene (env) functionally adopted by the human host to critically participate in placenta biogenesis), can become transactivated in a range of human non-placental cell-lines during exogenous virus infections. Aberrant expression of HERV-W has been associated with human diseases, such as cancer, multiple sclerosis, and schizophrenia. Based on published reports, transcriptional activities of HERV-W appear to be influenced by several mechanisms; binding of transcription factors to LTR promoters and enhancers outside of LTRs, genetic variation and alteration in DNA methylation and histone modification. Emerging mechanistic studies support the notion that HERV-W represents a potential marker or mediator of environmental exposures (e.g., virus infection) in the development of chronic complex diseases.
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Affiliation(s)
- Fang Li
- Department of Basic Medical Science, Changsha Medical University, Changsha, China.,Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Håkan Karlsson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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20
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Activation of endogenous human stem cell-associated retroviruses (SCARs) and therapy-resistant phenotypes of malignant tumors. Cancer Lett 2016; 376:347-59. [PMID: 27084523 DOI: 10.1016/j.canlet.2016.04.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/08/2016] [Accepted: 04/10/2016] [Indexed: 02/04/2023]
Abstract
Recent reports revealed consistent activation of specific endogenous retroviral elements in human preimplantation embryos and embryonic stem cells. Activity of stem cell associated retroviruses (SCARs) has been implicated in seeding thousands of human-specific regulatory sequences in the hESC genome. Activation of specific SCARs has been demonstrated in patients diagnosed with multiple types of cancer, autoimmune diseases, and neurodegenerative disorders, and appears associated with clinically lethal therapy resistant death-from-cancer phenotypes in a sub-set of cancer patients diagnosed with different types of malignant tumors. A hallmark feature of human-specific SCAR integration sites is deletions of ancestral DNA. Analysis of human-specific genetic loci of SCARs' stemness networks in tumor samples of TCGA cohorts representing 29 cancer types suggests that this approach may facilitate identification of pan-cancer genomic signatures of clinically-lethal disease defined by the presence of somatic non-silent mutations, gene-level copy number changes, and transcripts and proteins' expression of SCAR-regulated host genes. Present analyses indicate that multiple lines of strong circumstantial evidence support the hypothesis that activation of SCARs' networks may play an important role in cancer progression and metastasis, perhaps contributing to the emergence of clinically-lethal therapy-resistant death-from-cancer phenotypes.
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21
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MSRV envelope protein is a potent, endogenous and pathogenic agonist of human toll-like receptor 4: Relevance of GNbAC1 in multiple sclerosis treatment. J Neuroimmunol 2015; 291:29-38. [PMID: 26857492 DOI: 10.1016/j.jneuroim.2015.12.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 12/03/2015] [Accepted: 12/10/2015] [Indexed: 02/07/2023]
Abstract
Multiple sclerosis associated retrovirus envelope protein (MSRV-Env) was repeatedly detected in brain lesions and blood of multiple sclerosis (MS) patients. We performed the first pharmacological characterisation of MSRV-Env on recombinant and native human TLR4. MSRV-Env is a full and highly potent TLR4 agonist of endogenous origin. MSRV-Env induces TLR4-dependent pro-inflammatory stimulation of immune cells in vitro and in vivo, and impairs oligodendrocytes precursor cells differentiation to myelinating oligodendrocytes. MSRV-Env may play a role in chronic inflammation and impaired remyelination in MS. GNbAC1, a selective monoclonal antibody, antagonizes MSRV-Env pathogenic effects and represents an innovative therapeutic approach of MS.
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Curtin F, Perron H, Kromminga A, Porchet H, Lang AB. Preclinical and early clinical development of GNbAC1, a humanized IgG4 monoclonal antibody targeting endogenous retroviral MSRV-Env protein. MAbs 2015; 7:265-75. [PMID: 25427053 PMCID: PMC4623301 DOI: 10.4161/19420862.2014.985021] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/15/2014] [Accepted: 10/31/2014] [Indexed: 11/19/2022] Open
Abstract
Monoclonal antibodies (mAbs) play an increasing important role in the therapeutic armamentarium against multiple sclerosis (MS), an inflammatory and degenerative disorder of the central nervous system. Most of the mAbs currently developed for MS are immunomodulators blocking the inflammatory immune process. In contrast with mAbs targeting immune function, GNbAC1, a humanized IgG4 mAb, targets the multiple sclerosis associated retrovirus envelope (MSRV-Env) protein, an upstream factor in the pathophysiology of MS. MSRV-Env protein is of endogenous retroviral origin, expressed in MS brain lesions, and it is pro-inflammatory and toxic to the remyelination process, by preventing the differentiation of oligodendrocyte precursor cells. We present the preclinical and early clinical development results of GNbAC1. The specificity of GNbAC1 for its endogenous retroviral target is described. Efficacy of different mAb versions of GNbAC1 were assessed in MSRV-Env induced experimental allergic encephalitis (EAE), an animal model of MS. Because the target MSRV-Env is not expressed in animals, no relevant animal model exists for a proper in vivo toxicological program. An off-target 2-week toxicity study in mice was thus performed, and it showed an absence of safety risk. Additional in vitro analyses showed an absence of complement or antibody-dependent cytotoxicity as well as a low level of cross-reactivity to human tissues. The first-in-man clinical study in 33 healthy subjects and a long-term clinical study in 10 MS patients showed that GNbAC1 is well tolerated in humans without induction of immunogenicity and that it induces a pharmacodynamic response on MSRV biomarkers. These initial results suggest that the mAb GNbAC1 could be a safe long-term treatment for patients with MS with a unique therapeutic mechanism of action.
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Key Words
- ADCC, antibody-dependent cell-mediated cytotoxicity
- AE, adverse events
- AUC, area under the curve
- BLAST, Basic Local Alignment Search Tool
- CDC, complement-dependent cytotoxicity
- CDR, complementarity-determining regions
- Cmax, maximal concentration
- Cmin, minimal concentration
- HERV-W
- HERV-W, human endogenous retrovirus type W
- HLA, human leukocyte antigen
- MOG, myelin oligodendrocyte glycoprotein
- MS, multiple sclerosis
- MSRV
- MSRV, multiple sclerosis associated retrovirus
- MSRV-Env, multiple sclerosis associated retrovirus envelope protein
- PBMC, peripheral blood mononuclear cell
- SAE, serious adverse event
- SU, surface domain
- Syncytin
- TLR4, Toll-like receptor 4
- ch-GNbAC1, chimeric version of mAb GNbAC1
- drug safety
- human endogenous retrovirus
- mAb, monoclonal antibody
- monoclonal antibody
- mu-GNbAC1, murine version of mAb GNbAC1
- multiple sclerosis
- neurotoxicity
- toxicology
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MESH Headings
- Animals
- Antibodies, Monoclonal, Humanized/administration & dosage
- Antibodies, Monoclonal, Humanized/adverse effects
- Antibodies, Monoclonal, Humanized/immunology
- Antibody Specificity
- Encephalomyelitis, Autoimmune, Experimental/drug therapy
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Endogenous Retroviruses/immunology
- Female
- Gene Products, env/immunology
- HEK293 Cells
- Humans
- Immunoglobulin G/administration & dosage
- Immunoglobulin G/adverse effects
- Immunoglobulin G/immunology
- Male
- Mice
- Multiple Sclerosis/drug therapy
- Multiple Sclerosis/immunology
- Multiple Sclerosis/pathology
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Affiliation(s)
- François Curtin
- GeNeuro SA; Plan-les-Ouates/Geneva, Switzerland
- Division of Clinical Pharmacology and Toxicology; University of Geneva; Geneva, Switzerland
| | | | - Arno Kromminga
- Institute of Immunology; University Kiel; Kiel, Germany
- IPM Biotech; Hamburg, Germany
| | - Hervé Porchet
- GeNeuro SA; Plan-les-Ouates/Geneva, Switzerland
- Department of Pharmacology; University of Pretoria; Pretoria, South Africa
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Human endogenous retrovirus W activity in cartilage of osteoarthritis patients. BIOMED RESEARCH INTERNATIONAL 2014; 2014:698609. [PMID: 25136615 PMCID: PMC4130134 DOI: 10.1155/2014/698609] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 06/25/2014] [Indexed: 11/18/2022]
Abstract
The etiology of viruses in osteoarthritis remains controversial because the prevalence of viral nucleic acid sequences in peripheral blood or synovial fluid from osteoarthritis patients and that in healthy control subjects are similar. Until now the presence of virus has not been analyzed in cartilage. We screened cartilage and chondrocytes from advanced and non-/early osteoarthritis patients for parvovirus B19, herpes simplex virus-1, Epstein Barr virus, cytomegalovirus, human herpes virus-6, hepatitis C virus, and human endogenous retroviruses transcripts. Endogenous retroviruses transcripts, but none of the other viruses, were detected in 15 out the 17 patients. Sequencing identified the virus as HERV-WE1 and E2. HERV-W activity was confirmed by high expression levels of syncytin, dsRNA, virus budding, and the presence of virus-like particles in all advanced osteoarthritis cartilages examined. Low levels of HERV-WE1, but not E2 envelope RNA, were observed in 3 out of 8 non-/early osteoarthritis patients, while only 3 out of 7 chondrocytes cultures displayed low levels of syncytin, and just one was positive for virus-like particles. This study demonstrates for the first time activation of HERV-W in cartilage of osteoarthritis patients; however, a causative role for HERV-W in development or deterioration of the disease remains to be proven.
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Transcriptional derepression of the ERVWE1 locus following influenza A virus infection. J Virol 2014; 88:4328-37. [PMID: 24478419 DOI: 10.1128/jvi.03628-13] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Syncytin-1, a fusogenic protein encoded by a human endogenous retrovirus of the W family (HERV-W) element (ERVWE1), is expressed in the syncytiotrophoblast layer of the placenta. This locus is transcriptionally repressed in adult tissues through promoter CpG methylation and suppressive histone modifications. Whereas syncytin-1 appears to be crucial for the development and functioning of the human placenta, its ectopic expression has been associated with pathological conditions, such as multiple sclerosis and schizophrenia. We previously reported on the transactivation of HERV-W elements, including ERVWE1, during influenza A/WSN/33 virus infection in a range of human cell lines. Here we report the results of quantitative PCR analyses of transcripts encoding syncytin-1 in both cell lines and primary fibroblast cells. We observed that spliced ERVWE1 transcripts and those encoding the transcription factor glial cells missing 1 (GCM1), acting as an enhancer element upstream of ERVWE1, are prominently upregulated in response to influenza A/WSN/33 virus infection in nonplacental cells. Knockdown of GCM1 by small interfering RNA followed by infection suppressed the transactivation of ERVWE1. While the infection had no influence on CpG methylation in the ERVWE1 promoter, chromatin immunoprecipitation assays detected decreased H3K9 trimethylation (H3K9me3) and histone methyltransferase SETDB1 levels along with influenza virus proteins associated with ERVWE1 and other HERV-W loci in infected CCF-STTG1 cells. The present findings suggest that an exogenous influenza virus infection can transactivate ERVWE1 by increasing transcription of GCM1 and reducing H3K9me3 in this region and in other regions harboring HERV-W elements. IMPORTANCE Syncytin-1, a protein encoded by the env gene in the HERV-W locus ERVWE1, appears to be crucial for the development and functioning of the human placenta and is transcriptionally repressed in nonplacental tissues. Nevertheless, its ectopic expression has been associated with pathological conditions, such as multiple sclerosis and schizophrenia. In the present paper, we report findings suggesting that an exogenous influenza A virus infection can transactivate ERVWE1 by increasing the transcription of GCM1 and reducing the repressive histone mark H3K9me3 in this region and in other regions harboring HERV-W elements. These observations have implications of potential relevance for viral pathogenesis and for conditions associated with the aberrant transcription of HERV-W loci.
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García-Montojo M, de la Hera B, Varadé J, de la Encarnación A, Camacho I, Domínguez-Mozo M, Árias-Leal A, García-Martínez A, Casanova I, Izquierdo G, Lucas M, Fedetz M, Alcina A, Arroyo R, Matesanz F, Urcelay E, Alvarez-Lafuente R. HERV-W polymorphism in chromosome X is associated with multiple sclerosis risk and with differential expression of MSRV. Retrovirology 2014; 11:2. [PMID: 24405691 PMCID: PMC3892049 DOI: 10.1186/1742-4690-11-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 12/16/2013] [Indexed: 02/03/2023] Open
Abstract
Background Multiple Sclerosis (MS) is an autoimmune demyelinating disease that occurs more frequently in women than in men. Multiple Sclerosis Associated Retrovirus (MSRV) is a member of HERV-W, a multicopy human endogenous retroviral family repeatedly implicated in MS pathogenesis. MSRV envelope protein is elevated in the serum of MS patients and induces inflammation and demyelination but, in spite of this pathogenic potential, its exact genomic origin and mechanism of generation are unknown. A possible link between the HERV-W copy on chromosome Xq22.3, that contains an almost complete open reading frame, and the gender differential prevalence in MS has been suggested. Results MSRV transcription levels were higher in MS patients than in controls (U-Mann–Whitney; p = 0.004). Also, they were associated with the clinical forms (Spearman; p = 0.0003) and with the Multiple Sclerosis Severity Score (MSSS) (Spearman; p = 0.016). By mapping a 3 kb region in Xq22.3, including the HERV-W locus, we identified three polymorphisms: rs6622139 (T/C), rs6622140 (G/A) and rs1290413 (G/A). After genotyping 3127 individuals (1669 patients and 1458 controls) from two different Spanish cohorts, we found that in women rs6622139 T/C was associated with MS susceptibility: [χ2; p = 0.004; OR (95% CI) = 0.50 (0.31-0.81)] and severity, since CC women presented lower MSSS scores than CT (U-Mann–Whitney; p = 0.039) or TT patients (U-Mann–Whitney; p = 0.031). Concordantly with the susceptibility conferred in women, rs6622139*T was associated with higher MSRV expression (U-Mann–Whitney; p = 0.003). Conclusions Our present work supports the hypothesis of a direct involvement of HERV-W/MSRV in MS pathogenesis, identifying a genetic marker on chromosome X that could be one of the causes underlying the gender differences in MS.
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Affiliation(s)
- Marta García-Montojo
- Multiple Sclerosis Unit, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Profesor Martin Lagos s/n,, 28240, Madrid, Spain.
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Kim HS. Genomic impact, chromosomal distribution and transcriptional regulation of HERV elements. Mol Cells 2012; 33:539-44. [PMID: 22562360 PMCID: PMC3887755 DOI: 10.1007/s10059-012-0037-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/10/2012] [Accepted: 04/12/2012] [Indexed: 10/28/2022] Open
Abstract
Human endogenous retroviruses (HERVs) mediate structural variation and genomic instability based on their multiple copy number, inherent ability to mobilize via reverse transcriptase, and high sequence similarity. Moreover, they undergo multiple amplification and retrotransposition events, resulting in the widespread distribution of complete or partial retroviral sequences throughout the primate genome. As such, HERV elements have played important biological roles in genome evolution, and their long terminal repeat (LTR) elements contain numerous regulatory sequences, including effective promoters, enhancers, polyadenylation signals, and transcription factorbinding sites. Lastly, HERV elements are capable of influencing the expression of neighboring genes, a process that also contributed to primate evolution.
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Affiliation(s)
- Heui-Soo Kim
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735, Korea.
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Koshi K, Ushizawa K, Kizaki K, Takahashi T, Hashizume K. Expression of endogenous retrovirus-like transcripts in bovine trophoblastic cells. Placenta 2011; 32:493-9. [PMID: 21571366 DOI: 10.1016/j.placenta.2011.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 03/08/2011] [Accepted: 04/04/2011] [Indexed: 11/28/2022]
Abstract
UNLABELLED Endogenous retrovirus envelope elements are considered to participate in trophoblastic cell fusion and multinucleate cell formation in humans, mice, and sheep. However, there is limited information about their roles in the ruminant placenta. OBJECTIVES We explore and identify the endogenous retrovirus envelope element genes expressed in bovine trophoblasts. METHODS The NCBI UniGene database (Build #97 Bos taurus) was screened by in silico analysis. After cloning endogenous retrovirus envelope element-like transcript (ERVE), expression profiles were analyzed with quantitative RT-PCR and in situ hybrizaidation. RESULTS Two UniGene clusters, UniGene ID: Bt.68042 and Bt.85243, were detected, and ERVE-A gene was cloned. Weak expression of this gene was first detected on Day 20 of gestation, and the intensity of its expression increased up to Day 70 of gestation. The intensity of its expression was maintained throughout gestation in the placenta, and its specific expression in trophoblastic binucleate cells was confirmed by in situ hybridization. CONCLUSIONS bERVE-A has a similar sequence to human syncytin-1, although it lacks an intact envelope sequence, and is specifically expressed in binucleate cells. This is the first evidence that endogenous retrovirus envelope element genes are expressed in bovine binucleate cells.
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Affiliation(s)
- K Koshi
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Iwate University, Ueda, Morioka, Japan
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Age- and disease-dependent HERV-W envelope allelic variation in brain: association with neuroimmune gene expression. PLoS One 2011; 6:e19176. [PMID: 21559469 PMCID: PMC3084769 DOI: 10.1371/journal.pone.0019176] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 03/22/2011] [Indexed: 12/27/2022] Open
Abstract
Background The glycoprotein, Syncytin-1, is encoded by a human endogenous retrovirus (HERV)-W env gene and is capable of inducing neuroinflammation. The specific allele(s) responsible for Syncytin-1 expression in the brain is uncertain. Herein, HERV-W env diversity together with Syncytin-1 abundance and host immune gene profiles were examined in the nervous system using a multiplatform approach. Results HERV-W env sequences were encoded by multiple chromosomal encoding loci in primary human neurons compared with less chromosomal diversity in astrocytes and microglia (p<0.05). HERV-W env RNA sequences cloned from brains of patients with systemic or neurologic diseases were principally derived from chromosomal locus 7q21.2. Within the same specimens, HERV-W env transcript levels were correlated with the expression of multiple proinflammatory genes (p<0.05). Deep sequencing of brain transcriptomes disclosed the env transcripts to be the most abundant HERV-W transcripts, showing greater expression in fetal compared with healthy adult brain specimens. Syncytin-1's expression in healthy brain specimens was derived from multiple encoding loci and linked to distinct immune and developmental gene profiles. Conclusions Syncytin-1 expression in the brain during disease was associated with neuroinflammation and was principally encoded by a full length provirus. The present studies also highlighted the diversity in HERV gene expression within the brain and reinforce the potential contributions of HERV expression to neuroinflammatory diseases.
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The human microbiome in multiple sclerosis: pathogenic or protective constituents? Can J Neurol Sci 2011; 37 Suppl 2:S24-33. [PMID: 21246932 DOI: 10.1017/s031716710002240x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The human microbiome is comprised of commensal and pathogenic microorganisms, which exert diverse effects in close proximity to the site of intection as well as in remote tissues through immune-mediated mechanisms. Multiple infectious agents have been implicated in the pathogenesis of multiple sclerosis (MS) with variable findings depending on the agent, techniques, and disease phenotype. Herein, the contributions of individual infectious agents to MS and their effects on the immune and nervous systems are reviewed, focusing on herpes viruses, coronaviruses, retroviruses, and synchronic infections. While infectious agents are often assumed to be pathogenic, their effects might also be beneficial to the host in the long-term, depending on age and the type of immunogen/pathogen exposure, as proposed by the hygiene hypothesis. The human microbiome has potential impact on future diagnostic and therapeutic issues in MS.
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Black SG, Arnaud F, Palmarini M, Spencer TE. Endogenous retroviruses in trophoblast differentiation and placental development. Am J Reprod Immunol 2010; 64:255-64. [PMID: 20528833 PMCID: PMC4198168 DOI: 10.1111/j.1600-0897.2010.00860.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Endogenous retroviruses (ERVs) are present in the genome of all vertebrates and originated from infections of the germline of the host by exogenous retroviruses. ERVs have coevolved with their hosts for millions of years and are recognized to contribute to genome plasticity, protect the host against infection of related pathogenic and exogenous retroviruses, and play a vital role in development of the placenta. Consequently, some ERVs have been positively selected and maintained in the host genome throughout evolution. This review will focus on the critical role of ERVs in development of the mammalian placenta and specifically highlight the biological role of sheep JSRV-related endogenous betaretroviruses in conceptus (embryo and associated extraembryonic membranes) development.
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Affiliation(s)
- Sarah G. Black
- Center for Animal Biotechnology and Genomics, Department of Animal Science, Texas A&M University, College Station, TX, USA
| | - Fredrick Arnaud
- Institute of Comparative Medicine, University of Glasgow Veterinary School, Glasgow, Scotland, UK
| | - Massimo Palmarini
- Institute of Comparative Medicine, University of Glasgow Veterinary School, Glasgow, Scotland, UK
| | - Thomas E. Spencer
- Center for Animal Biotechnology and Genomics, Department of Animal Science, Texas A&M University, College Station, TX, USA
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Antony JM, Deslauriers AM, Bhat RK, Ellestad KK, Power C. Human endogenous retroviruses and multiple sclerosis: innocent bystanders or disease determinants? Biochim Biophys Acta Mol Basis Dis 2010; 1812:162-76. [PMID: 20696240 PMCID: PMC7172332 DOI: 10.1016/j.bbadis.2010.07.016] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 07/14/2010] [Accepted: 07/26/2010] [Indexed: 12/21/2022]
Abstract
Human endogenous retroviruses (HERVs) constitute 5–8% of human genomic DNA and are replication incompetent despite expression of individual HERV genes from different chromosomal loci depending on the specific tissue. Several HERV genes have been detected as transcripts and proteins in the central nervous system, frequently in the context of neuroinflammation. The HERV-W family has received substantial attention in large part because of associations with diverse syndromes including multiple sclerosis (MS) and several psychiatric disorders. A HERV-W-related retroelement, multiple sclerosis retrovirus (MSRV), has been reported in MS patients to be both a biomarker as well as an effector of aberrant immune responses. HERV-H and HERV-K have also been implicated in MS and other neurological diseases but await delineation of their contributions to disease. The HERV-W envelope-encoded glycosylated protein, syncytin-1, is encoded by chromosome 7q21 and exhibits increased glial expression within MS lesions. Overexpression of syncytin-1 in glia induces endoplasmic reticulum stress leading to neuroinflammation and the induction of free radicals, which damage proximate cells. Syncytin-1's receptor, ASCT1 is a neutral amino acid transporter expressed on glia and is suppressed in white matter of MS patients. Of interest, antioxidants ameliorate syncytin-1's neuropathogenic effects raising the possibility of using these agents as therapeutics for neuroinflammatory diseases. Given the multiple insertion sites of HERV genes as complete and incomplete open reading frames, together with their differing capacity to be expressed and the complexities of individual HERVs as both disease markers and bioactive effectors, HERV biology is a compelling area for understanding neuropathogenic mechanisms and developing new therapeutic strategies.
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Brudek T, Christensen T, Aagaard L, Petersen T, Hansen HJ, Møller-Larsen A. B cells and monocytes from patients with active multiple sclerosis exhibit increased surface expression of both HERV-H Env and HERV-W Env, accompanied by increased seroreactivity. Retrovirology 2009; 6:104. [PMID: 19917105 PMCID: PMC2780989 DOI: 10.1186/1742-4690-6-104] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Accepted: 11/16/2009] [Indexed: 02/04/2023] Open
Abstract
Background The etiology of the neurogenerative disease multiple sclerosis (MS) is unknown. The leading hypotheses suggest that MS is the result of exposure of genetically susceptible individuals to certain environmental factor(s). Herpesviruses and human endogenous retroviruses (HERVs) represent potentially important factors in MS development. Herpesviruses can activate HERVs, and HERVs are activated in MS patients. Results Using flow cytometry, we have analyzed HERV-H Env and HERV-W Env epitope expression on the surface of PBMCs from MS patients with active and stable disease, and from control individuals. We have also analyzed serum antibody levels to the expressed HERV-H and HERV-W Env epitopes. We found a significantly higher expression of HERV-H and HERV-W Env epitopes on B cells and monocytes from patients with active MS compared with patients with stable MS or control individuals. Furthermore, patients with active disease had relatively higher numbers of B cells in the PBMC population, and higher antibody reactivities towards HERV-H Env and HERV-W Env epitopes. The higher antibody reactivities in sera from patients with active MS correlate with the higher levels of HERV-H Env and HERV-W Env expression on B cells and monocytes. We did not find such correlations for stable MS patients or for controls. Conclusion These findings indicate that both HERV-H Env and HERV-W Env are expressed in higher quantities on the surface of B cells and monocytes in patients with active MS, and that the expression of these proteins may be associated with exacerbation of the disease.
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Affiliation(s)
- Tomasz Brudek
- Department of Medical Microbiology and Immunology, University of Aarhus, DK-8000 Aarhus C, Denmark.
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Oppelt P, Strick R, Strissel PL, Winzierl K, Beckmann MW, Renner SP. Expression of the human endogenous retroviruse-W envelope gene syncytin in endometriosis lesions. Gynecol Endocrinol 2009; 25:741-7. [PMID: 19903052 DOI: 10.3109/09513590903184142] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND None of the existing theories provides a satisfactory explanation of the development of endometriosis. One hypothesis that may lead to further clarification is that the expression of specific proteins of human endogenous retroviruses (HERVs) might influence the development of endometriosis lesions. Such endogenous retroviral proteins include syncytin, coded by HERV-W, which is associated with the physiological development of the placenta during pregnancy. This study investigated the influence of HERV-W gene expression in endometriosis foci (EM) quantitatively at the RNA level. MATERIALS AND METHODS Specific RNA expression of syncytin (HERV-W) was investigated in various endometrial tissues from 42 patients (with normal endometrium, postmenopausal endometrium, EM, and endometrial carcinoma). RNA was isolated from the tissue samples and transcribed into DNA using reverse transcriptase polymerase chain reaction. The resulting DNA fragments were analyzed using agarose gel electrophoresis and assessed quantitatively. RESULTS Normalized syncytin expression was low in EM. In Histologically normal endometrium from endometriosis patients, the expression of normalized syncytin was seven times higher in comparison with the histologically normal endometrium in the control group. CONCLUSIONS HERV-W syncytin expression apparently does not play a role in EM. However, it may possibly influence the development of endometriosis because of increased expression in normal endometrium in endometriosis patients.
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Affiliation(s)
- Peter Oppelt
- Department of Gynecology and Obstetrics, University of Erlangen, Erlangen, Germany.
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Varela M, Spencer TE, Palmarini M, Arnaud F. Friendly viruses: the special relationship between endogenous retroviruses and their host. Ann N Y Acad Sci 2009; 1178:157-72. [PMID: 19845636 PMCID: PMC4199234 DOI: 10.1111/j.1749-6632.2009.05002.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Endogenous retroviruses (ERVs) are present in the genome of all vertebrates and have coevolved with their hosts for millions of years. Some ERVs play a critical role in placental development, contribute to genome plasticity, and protect the host against infection of related pathogenic and exogenous retroviruses, thus some ERVs have been positively selected and maintained in the host genome. The sheep genome contains 27 endogenous retroviruses (enJSRVs) related to the pathogenic Jaagsiekte sheep retrovirus (JSRV), the causative agent of a transmissible lung cancer in sheep. enJSRVs are able to protect their host against JSRV infection by blocking different steps of the viral replication cycle. In addition, enJSRVs are absolutely required for sheep placental development. Thus, enJSRVs-JSRV provides a unique and interesting model to study the symbiotic relationship and interplay between host ERVs and evolution. This review will provide some examples of the biological functions of ERVs. In particular, the role of ERVs in reproductive biology and in protecting the host against pathogenic retrovirus infections will be emphasized using enJSRVs/JSRV and the sheep as a model.
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Affiliation(s)
- Mariana Varela
- Institute of Comparative Medicine, University of Glasgow Veterinary School, Glasgow, Scotland, UK
| | - Thomas E. Spencer
- Laboratory for Uterine Biology and Pregnancy, Department of Animal Science, Texas A&M University, College Station, Texas, USA
| | - Massimo Palmarini
- Institute of Comparative Medicine, University of Glasgow Veterinary School, Glasgow, Scotland, UK
| | - Frederick Arnaud
- Institute of Comparative Medicine, University of Glasgow Veterinary School, Glasgow, Scotland, UK
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Oluwole SOA, Yao Y, Conradi S, Kristensson K, Karlsson H. Elevated levels of transcripts encoding a human retroviral envelope protein (syncytin) in muscles from patients with motor neuron disease. ACTA ACUST UNITED AC 2009; 8:67-72. [PMID: 17453631 DOI: 10.1080/17482960600864207] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Retroviral components of both exogenous and endogenous origins have been associated with nervous system diseases in both animals and humans. In the present study, the levels of transcripts from elements in the human endogenous retrovirus (HERV) W family were determined in muscle biopsies from patients with motor neuron disease (MND) and control subjects. Transcripts from the HERV-W element on chromosome 7q21.2 encoding syncytin and from the SOD1 gene were detected at elevated levels in biopsies from the most affected muscles from MND patients compared to biopsies from control individuals. According to a recent study, syncytin is expressed in microglia in normal brain and can be up-regulated in macrophages/microglia during inflammation. Although syncytin may have cytotoxic effects, it is therefore more likely that the present findings reflect a macrophage response in the muscles undergoing neurogenic atrophy than a primary pathogenetic event in MND.
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Mameli G, Poddighe L, Astone V, Delogu G, Arru G, Sotgiu S, Serra C, Dolei A. Novel reliable real-time PCR for differential detection of MSRVenv and syncytin-1 in RNA and DNA from patients with multiple sclerosis. J Virol Methods 2009; 161:98-106. [PMID: 19505508 DOI: 10.1016/j.jviromet.2009.05.024] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 05/20/2009] [Accepted: 05/28/2009] [Indexed: 01/01/2023]
Abstract
Two components of the HERV-W family of human endogenous retroviruses are activated during multiple sclerosis (MS) and proposed immunopathogenic co-factors: MSRV (MS-associated retrovirus), and ERVWE1 (whose env protein, syncytin-1, reaches the plasma membrane). MSRVenv and syncytin-1 are closely related, and difficult to distinguish each other. The sequences of extracellular MSRVenv and of syncytin-1 available in GenBank were compared with those found in MS patients and controls of the cohort under study. With respect to syncytin-1, MSRVenv sequences have a 12-nucleotide insertion in the trans-membrane moiety. Based on this insertion, discriminatory real-time PCR assays were developed, that can amplify selectively either MSRVenv or syncytin-1. The data of MS patients and controls indicated that MSRV and ERVWE1 are both expressed in the brain of MS patients, while only MSRV is present in the blood; MSRV was released in culture by PBMCs of MSRV-producer individuals. These cells expressed the complete MSRVenv gene in the absence of syncytin-1 expression, up to the final, fully glycosylated envelope protein product, since western blot staining with anti-HERV-Wenv antibody detected two bands of the same molecular weight (73 and 61kDa) of the fully glycosylated and partially glycosylated HERV-Wenv uncleaved proteins. Beyond MSRVenv DNA copy numbers were more abundant in MS patients than in healthy humans, while syncytin-1 were unchanged. These findings reinforce the link between MSRV and MS.
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Affiliation(s)
- Giuseppe Mameli
- Section of Microbiology, Department of Biomedical Sciences, Centre of Excellence for Biotechnology Development and Biodiversity Research, University of Sassari, Viale San Pietro 43B, Sassari, Italy
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Laufer G, Mayer J, Mueller BF, Mueller-Lantzsch N, Ruprecht K. Analysis of transcribed human endogenous retrovirus W env loci clarifies the origin of multiple sclerosis-associated retrovirus env sequences. Retrovirology 2009; 6:37. [PMID: 19368703 PMCID: PMC2672075 DOI: 10.1186/1742-4690-6-37] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Accepted: 04/15/2009] [Indexed: 12/19/2022] Open
Abstract
Background Multiple sclerosis-associated retrovirus (MSRV) RNA sequences have been detected in patients with multiple sclerosis (MS) and are related to the multi-copy human endogenous retrovirus family type W (HERV-W). Only one HERV-W locus (ERVWE1) codes for a complete HERV-W Env protein (Syncytin-1). Syncytin-1 and the putative MSRV Env protein have been involved in the pathogenesis of MS. The origin of MSRV and its precise relation to HERV-W were hitherto unknown. Results By mapping HERV-W env cDNA sequences (n = 332) from peripheral blood mononuclear cells of patients with MS and healthy controls onto individual genomic HERV-W env elements, we identified seven transcribed HERV-W env loci in these cells, including ERVWE1. Transcriptional activity of individual HERV-W env elements did not significantly differ between patients with MS and controls. Remarkably, almost 30% of HERV-W env cDNAs were recombined sequences that most likely arose in vitro between transcripts from different HERV-W env elements. Re-analysis of published MSRV env sequences revealed that all of them can be explained as originating from genomic HERV-W env loci or recombinations among them. In particular, a MSRV env clone previously used for the generation of monoclonal antibody 6A2B2, detecting an antigen in MS brain lesions, appears to be derived from a HERV-W env locus on chromosome Xq22.3. This locus harbors a long open reading frame for an N-terminally truncated HERV-W Env protein. Conclusion Our data clarify the origin of MSRV env sequences, have important implications for the status of MSRV, and open the possibility that a protein encoded by a HERV-W env element on chromosome Xq22.3 may be expressed in MS brain lesions.
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Affiliation(s)
- Georg Laufer
- Institute of Virology, Saarland University Hospital, Homburg, Germany.
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Preferential epigenetic suppression of the autonomous MusD over the nonautonomous ETn mouse retrotransposons. Mol Cell Biol 2009; 29:2456-68. [PMID: 19273603 DOI: 10.1128/mcb.01383-08] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nonautonomous retrotransposon subfamilies are often amplified in preference to their coding-competent relatives. However, the mechanisms responsible for such replicative success are poorly understood. Here, we demonstrate that the autonomous MusD long terminal repeat (LTR) retrotransposons are subject to greater epigenetic silencing than their nonautonomous cousins, the early transposons (ETns), which are expressed at a 170-fold-higher level than MusD in mouse embryonic stem (ES) cells. We show that, in ES cells, 5' LTRs and the downstream region of MusD elements are more heavily methylated and are associated with less-activating and more-repressive histone modifications than the highly similar ETnII sequences. The internal region of MusD likely contributes to their silencing, as transgenes with MusD, compared to those with ETnII sequences, show reduced reporter gene expression and a higher level of repressive histone marks. Genomic distribution patterns of MusD and ETn elements are consistent with stronger selection against MusD elements within introns, suggesting that MusD-associated silencing marks can negatively impact genes. We propose a model in which nonautonomous retrotransposons may gain transcriptional and retrotranspositional advantages over their coding-competent counterparts by elimination of the CpG-rich retroviral sequence targeting the autonomous subfamilies for silencing.
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Ruprecht K, Gronen F, Sauter M, Best B, Rieckmann P, Mueller-Lantzsch N. Lack of immune responses against multiple sclerosis-associated retrovirus/human endogenous retrovirus W in patients with multiple sclerosis. J Neurovirol 2008; 14:143-51. [PMID: 18444086 DOI: 10.1080/13550280801958922] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The multiple sclerosis-associated retrovirus (MSRV), originally identified in cell cultures from patients with multiple sclerosis (MS), is closely related to the human endogenous retrovirus family type W (HERV-W). Different lines of evidence appear compatible with a potential role of MSRV/HERV-W in the pathogenesis of MS. The authors therefore analyzed humoral and cellular immune responses against MSRV/HERV-W antigens in patients with MS, patients with other inflammatory and noninflammatory neurological diseases, and healthy controls, using indirect immunofluorescence and enzyme-linked immunospot assays. Antibodies against the HERV-W envelope (Env) protein, Syncytin-1, were found in one of 50 patients with MS and none of 59 controls, whereas antibodies against MSRV matrix and capsid (Gag) or Env proteins were not detectable in any of the patients or controls. Similarly, in a screening of human leukocyte antigen (HLA)-B7+ patients with MS (n = 23) and controls (n = 29) for cytotoxic T-lymphocyte responses against 36 predicted HLA-B7-restricted MSRV/HERV-W Gag-, protease-, and reverse transcriptase-derived peptides, no such responses could be detected in any of the subjects studied. These data suggest that there are no appreciable humoral or cellular immune responses against MSRV/HERV-W in patients with MS. While this may be due to immunological tolerance of physiologically expressed HERV-W proteins, strategies other than measurement of immune responses will be required to further elucidate the relationship between MSRV/HERV-W and MS.
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Affiliation(s)
- Klemens Ruprecht
- Institute for Virology, Saarland University Hospital, Homburg/Saar, Germany.
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Abstract
The capacity to integrate into the chromosomal DNA of germ-line cells has endowed retroviruses with the potential to be vertically transmitted from generation to generation and eventually become fixed in the genomes of the entire population. This has been independently accomplished by several ancient retroviruses that invaded the genomes of our early and more recent primate and hominoid ancestors. Some of the inherited elements then proliferated in the genome, resulting in a number of lineages with complex phylogenetic patterns. Although the vast majority of chromosomally integrated retroelements have suffered inactivating mutations and deletions, a significant impact on various aspects of human biology has been recently revealed and evidence for the present activity of at least one human endogenous retrovirus family continues to accumulate.
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Voisset C, Weiss RA, Griffiths DJ. Human RNA "rumor" viruses: the search for novel human retroviruses in chronic disease. Microbiol Mol Biol Rev 2008; 72:157-96, table of contents. [PMID: 18322038 PMCID: PMC2268285 DOI: 10.1128/mmbr.00033-07] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Retroviruses are an important group of pathogens that cause a variety of diseases in humans and animals. Four human retroviruses are currently known, including human immunodeficiency virus type 1, which causes AIDS, and human T-lymphotropic virus type 1, which causes cancer and inflammatory disease. For many years, there have been sporadic reports of additional human retroviral infections, particularly in cancer and other chronic diseases. Unfortunately, many of these putative viruses remain unproven and controversial, and some retrovirologists have dismissed them as merely "human rumor viruses." Work in this field was last reviewed in depth in 1984, and since then, the molecular techniques available for identifying and characterizing retroviruses have improved enormously in sensitivity. The advent of PCR in particular has dramatically enhanced our ability to detect novel viral sequences in human tissues. However, DNA amplification techniques have also increased the potential for false-positive detection due to contamination. In addition, the presence of many families of human endogenous retroviruses (HERVs) within our DNA can obstruct attempts to identify and validate novel human retroviruses. Here, we aim to bring together the data on "novel" retroviral infections in humans by critically examining the evidence for those putative viruses that have been linked with disease and the likelihood that they represent genuine human infections. We provide a background to the field and a discussion of potential confounding factors along with some technical guidelines. In addition, some of the difficulties associated with obtaining formal proof of causation for common or ubiquitous agents such as HERVs are discussed.
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Affiliation(s)
- Cécile Voisset
- CNRS-UMR8161, Institut de Biologie de Lille et Institut Pasteur de Lille, Lille, France
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42
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Asp L, Nellåker C, Karlsson H. Influenza A virus transactivates the mouse envelope gene encoding syncytin B and its regulator, glial cells missing 1. J Neurovirol 2007; 13:29-37. [PMID: 17454446 DOI: 10.1080/13550280601103125] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Recently, two candidate analogs for human syncytin, denoted syncytins A and B, were identified in the murine genome. These were found to have expression patterns and functions similar to human syncytin. In addition, the identification of glial cells missing (GCM)-binding motifs in putative promoter regions of the mouse syncytins imply analogous regulation. Transcriptional modulation of syncytin by exogenous agents was recently suggested by studies reporting transactivation of syncytin in human cell lines following virus infections. The authors report that influenza A virus infection increased the levels of transcripts encoding Gcm1 and syncytin B, but not syncytin A, in NIH-3T3 cells as well as in mouse primary neurons or glia. Overexpression of human GCM1 in NIH-3T3 cells resulted in increased levels of transcripts encoding syncytin B but not syncytin A. Systemic administration of neurotropic influenza A virus resulted in a neuronal infection and increased levels of Gcm1-encoding transcripts in brains of young mice. The mouse may therefore be useful for studies on the expression and function of endogenous retroviral envelope genes and transcription factors regulating their expression in the placenta and brain during physiological or pathological conditions.
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Affiliation(s)
- Linnéa Asp
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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43
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Weis S, Llenos IC, Sabunciyan S, Dulay JR, Isler L, Yolken R, Perron H. Reduced expression of human endogenous retrovirus (HERV)-W GAG protein in the cingulate gyrus and hippocampus in schizophrenia, bipolar disorder, and depression. J Neural Transm (Vienna) 2007; 114:645-55. [PMID: 17219017 DOI: 10.1007/s00702-006-0599-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Accepted: 10/28/2006] [Indexed: 12/01/2022]
Abstract
The human endogenous retrovirus (HERV)-W multicopy family was identified in human DNA from the previously characterized multiple sclerosis associated retroviral element (MSRV). Upregulation of the HERV-W POL has been reported in cerebrospinal fluid of patients with schizophrenia. The expression of capsid (GAG) protein of HERV-W was studied by immunohistochemistry and western blotting in postmortem brain tissue of the anterior cingulate cortex and hippocampal formation of normal controls and of patients with schizophrenia, bipolar disorder and major depression. A physiological expression of GAG protein was detected in neurons as well as astroglial cells in normal brain both in the anterior cingulate cortex and in the hippocampal formation. There was a statistically significant reduction of this expression in neurons and astroglial cells in brains from individuals with schizophrenia, major depression, and bipolar disorder. The results from the present study confirm that GAG protein encoded by the HERV-W multicopy gene family is expressed in cells of the central nervous system under normal conditions. Our findings of a cell type-, brain region- and disease-specific reduced expression in schizophrenia, major depression, and bipolar disorder are compatible with a pathophysiological role of HERVs in human brain disorders. The causes and biological consequences of this differential regulation will be the subject of further investigations.
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Affiliation(s)
- S Weis
- Laboratory of Brain Research and Neuropathology, Departments of Psychiatry and Pathology, Uniformed Services University of the Health Sciences, and Stanley Medical Research Institute, Bethesda, MD, USA.
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Antony JM, Izad M, Bar-Or A, Warren KG, Vodjgani M, Mallet F, Power C. Quantitative analysis of human endogenous retrovirus-W env in neuroinflammatory diseases. AIDS Res Hum Retroviruses 2006; 22:1253-9. [PMID: 17209768 DOI: 10.1089/aid.2006.22.1253] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Although human endogenous retroviruses (HERVs) constitute 8% of the human genome, their role(s) in health and disease remain uncertain. Nonetheless, increased HERV gene activity has been reported in neuroinflammatory diseases such as multiple sclerosis (MS). The human endogenous retrovirus (HERV)-W7q envelope gene encodes a glycosylated envelope protein, syncytin-1, which is expressed in many tissues. Analysis of HERV envelopes (env) revealed a selectively increased abundance of syncytin-1 encoding RNA in brains from patients with MS (p<0.01) relative to non-MS patients. However, HERV env expression from blood-derived leukocytes did not differ between groups. A quantitative PCR-based assay for syncytin-1 RNA showed that median viral RNA levels were higher in brains of MS patients (5.0 log10 copies/microg RNA) relative to non-MS patients (4.6 log10 copies/microg RNA) (p<0.05). Median syncytin-1 DNA levels in MS brains (9.8 log10/microg DNA) were higher than non-MS brain tissue (7.9 log10/microg DNA) (p<0.001) without evidence of new integration events. In contrast, there were no differences in syncytin-1 RNA copy numbers between groups in both CSF (non-MS: 5.0 log10/ml versus MS: 3.8 log10/ml) and plasma (non-MS: 5.033 log10/ml versus MS: 2.9 log10/ml). These observations emphasize the selective induction of syncytin-1 in brain tissue of MS patients but also illustrate the complex dynamics of this retroelement in neuroinflammatory processes.
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Affiliation(s)
- Joseph M Antony
- Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada
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45
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Muir A, Lever AML, Moffett A. Human endogenous retrovirus-W envelope (syncytin) is expressed in both villous and extravillous trophoblast populations. J Gen Virol 2006; 87:2067-2071. [PMID: 16760410 DOI: 10.1099/vir.0.81412-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The placenta is unique amongst normal tissues in transcribing numerous different human endogenous retroviruses at high levels. In this study, RT-PCR and immunohistochemistry were used to investigate the expression of syncytin in human trophoblast. Syncytin transcripts were found in first-trimester trophoblast cells with both villous and extravillous phenotypes and also in the JAR and JEG-3 choriocarcinoma cell lines. Syncytin protein was detected in villous trophoblast and in all extravillous trophoblast subpopulations of first- and second-trimester placental tissues. It was also present in ectopic trophoblast from tubal implantations. This study confirms that syncytin is expressed widely by a variety of normal human trophoblast populations, as well as choriocarcinoma cell lines.
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Affiliation(s)
- A Muir
- Research Group in Human Reproductive Immunobiology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - A M L Lever
- Department of Medicine, University of Cambridge, Level 5, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK
| | - A Moffett
- Research Group in Human Reproductive Immunobiology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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Nellåker C, Yao Y, Jones-Brando L, Mallet F, Yolken RH, Karlsson H. Transactivation of elements in the human endogenous retrovirus W family by viral infection. Retrovirology 2006; 3:44. [PMID: 16822326 PMCID: PMC1539011 DOI: 10.1186/1742-4690-3-44] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Accepted: 07/06/2006] [Indexed: 11/30/2022] Open
Abstract
Background Aberrant expression of human endogenous retrovirus (HERV) elements in the W family has previously been associated with schizophrenia, multiple sclerosis and preeclampsia. Little is know regarding the basal expression, transcriptional regulation and functional significance of individual HERV-elements. Since viral infections have previously been reported to transactivate retroviral long terminal repeat regions we examined the basal expression of HERV-W elements and following infections by influenza A/WSN/33 and Herpes simplex 1 viruses in human cell-lines. Methods Relative levels of transcripts encoding HERV-W elements and cellular genes were analyzed by qPCR methods. An analysis of amplicon melting temperatures was used to detect variations in the frequencies of amplicons in discrete ranges of such melting temperatures. These frequency-distributions were taken as proxy markers for the repertoires of transcribed HERV-W elements in the cells. Results We report cell-specific expression patterns of HERV-W elements during base-line conditions. Expressed elements include those with intact regulatory long terminal repeat regions (LTRs) as well as elements flanked by truncated LTRs. Subsets of HERV-W elements were transactivated by viral infection in the different cell-lines. Transcriptional activation of these elements, including that encoding syncytin, was dependent on viral replication and was not induced by antiviral responses. Serum deprivation of cells induced similar changes in the expression of HERV-W elements suggesting that the observed phenomena are, in part, an effect of cellular stress. Conclusion We found that HERV-W elements, including elements lacking regulatory LTRs, are expressed in cell-specific patterns which can be modulated by environmental influences. This brings into light that mechanisms behind the regulation of expression of HERV-W elements are more complex than previously assumed and suggests biological functions of these transcripts.
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Affiliation(s)
- Christoffer Nellåker
- The Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 171 77 Stockholm, Sweden
| | - Yuanrong Yao
- The Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 171 77 Stockholm, Sweden
| | - Lorraine Jones-Brando
- The Stanley Division of Developmental Neurovirology, The Johns Hopkins University School of Medicine, 600 N Wolfe Street, Blalock 1105, Baltimore, MD, 21287-4933, USA
| | - François Mallet
- UMR 2714 CNRS-bioMérieux, IFR128 BioSciences Lyon-Gerland Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon cedex 07, France
| | - Robert H Yolken
- The Stanley Division of Developmental Neurovirology, The Johns Hopkins University School of Medicine, 600 N Wolfe Street, Blalock 1105, Baltimore, MD, 21287-4933, USA
| | - Håkan Karlsson
- The Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 171 77 Stockholm, Sweden
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47
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Yao Y, Nellåker C, Karlsson H. Evaluation of minor groove binding probe and Taqman probe PCR assays: Influence of mismatches and template complexity on quantification. Mol Cell Probes 2006; 20:311-6. [PMID: 16704921 DOI: 10.1016/j.mcp.2006.03.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Revised: 03/03/2006] [Accepted: 03/24/2006] [Indexed: 11/25/2022]
Abstract
Real-time PCR assays using 3'-minor groove binder (MGB) or Taqman probes are widely used for clinical virological testing and mutation/polymorphism detection. We compared a 3'-MGB probe to a conventional Taqman probe for linearity, sensitivity, specificity and dynamic range. The performance of the two assays was compared using plasmids containing different mismatches or using human genomic DNA as a template. Comparable linearity and sensitivity were observed for the MGB and the Taqman probe assays. Using standard conditions, none of the assays were sequence-specific. Up to five mismatches generated a detectable signal in the Taqman probe assay. The performance of the Taqman as well as the MGB probe assay was influenced by the complexity of the template, the latter, however, to a lesser degree. Overall, these results highlight the advantages of the MGB probe over the Taqman probe regarding mismatch discrimination, but suggest that optimization of reaction conditions and verification of the specificity are necessary also for MGB probes.
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Affiliation(s)
- Yuanrong Yao
- Department of Neuroscience, Karolinska Institute, Retzius vag 8, S-171 77 Stockholm, Sweden.
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Matousková M, Blazková J, Pajer P, Pavlícek A, Hejnar J. CpG methylation suppresses transcriptional activity of human syncytin-1 in non-placental tissues. Exp Cell Res 2006; 312:1011-20. [PMID: 16427621 DOI: 10.1016/j.yexcr.2005.12.010] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Revised: 12/06/2005] [Accepted: 12/13/2005] [Indexed: 11/20/2022]
Abstract
Syncytin-1 is a captive envelope glycoprotein encoded by one of human endogenous retroviruses W. It is expressed exclusively in the placental trophoblast where it participates in cell-to-cell fusion during differentiation of syncytiotrophobast. In other tissues, however, syncytin-1 expression must be kept in check because inadvertent cell fusion might be dangerous for tissue organization and integrity. We describe here an inverse correlation between CpG methylation of syncytin-1 5' long terminal repeat and its expression. Hypomethylation of the syncytin-1 5' long terminal repeat in the placenta and in the choriocarcinoma-derived cell line BeWo was detected. However, other analyzed primary cells and cell lines non-expressing syncytin-1 contain proviruses heavily methylated in this sequence. CpG methylation of syncytin-1 is resistant to the effect of the demethylating agent 5-azacytidine. The inhibitory role of CpG methylation is further confirmed by transient transfection of in-vitro-methylated syncytin-1 promoter-driven reporter construct. Altogether, we conclude that CpG methylation plays a principal role in the transcriptional suppression of syncytin-1 in non-placental tissues, and, in contrast, demethylation of the syncytin-1 promoter in trophoblast is a prerequisite for its expression and differentiation of multinucleated syncytiotrophoblast.
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Affiliation(s)
- Magda Matousková
- Department of Cellular and Viral Genetics, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Flemingovo námìstí 2, 16637 Prague 6, Czech Republic
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Yi JM, Kim HS. Molecular evolution of the HERV-E family in primates. Arch Virol 2006; 151:1107-16. [PMID: 16385394 DOI: 10.1007/s00705-005-0701-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Accepted: 11/25/2005] [Indexed: 10/25/2022]
Abstract
More than 50 copies of HERV-E family elements have been estimated to exist in the human genome. Here we examined the recent evolutionary history of the HERV-E family by a PCR approach using genomic DNA from hominoid primates and a human monochromosomal panel. From the HERV-E family, 25 and 68 env fragments, were identified and analyzed from hominoid primates and human chromosomes 1, 2, 3, 4, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 19, X, and Y, respectively. They showed 76.7-99.6% sequence similarity to that of HERV-E (accession no. M10976). Phylogenetic analysis of HERV-E env family distinctively divided into two groups (groups I and II) that each contained three subgroups. Divergence times of the two groups were estimated as 10.7 MYr for group I and 41.3 MYr for group II using an average evolutionary rate of 0.3% per MYr. These data are consistent with that of PCR analysis, which showed a band of the HERV-E family in the genomes of the hominoids, Old World monkeys, and New World monkeys. Therefore, the HERV-E family may have integrated into the primate genome after prosimians and New World monkeys diverged. Then they proliferated extensively in the genome of humans and great apes during primate evolution.
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Affiliation(s)
- J-M Yi
- Division of Biological Sciences, College of Natural Sciences, Pusan National University, Pusan, Korea
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50
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Ruprecht K, Obojes K, Wengel V, Gronen F, Kim KS, Perron H, Schneider-Schaulies J, Rieckmann P. Regulation of human endogenous retrovirus W protein expression by herpes simplex virus type 1: Implications for multiple sclerosis. J Neurovirol 2006; 12:65-71. [PMID: 16595376 DOI: 10.1080/13550280600614973] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The multiple sclerosis-associated retrovirus (MSRV), originally identified in cell cultures from patients with multiple sclerosis (MS), is closely related to the human endogenous retrovirus family W (HERV-W). Recently, HERV-W gag and env protein expression was demonstrated in MS lesions in situ. Here, the authors show that HERV-W gag and env proteins are induced by herpes simplex virus type 1 (HSV-1) in neuronal and brain endothelial cells in vitro. The transactivation of HERV-W proteins by HSV-1 could enhance their potential oligodendrotoxic and immunopathogenic effects, representing a mechanism by which HSV-1, and possibly also other herpesviruses associated with MS, may be linked to the pathogenesis of this disease.
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Affiliation(s)
- Klemens Ruprecht
- Department of Neurology, Clinical Research Unit for Multiple Sclerosis and Neuroimmunology, Würzburg, Germany.
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