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Evans TA, Feltrin AS, Benjamin KJ, Katipalli T, Hyde T, Kleinman JE, Weinberger DR, Paquola AC, Erwin JA. Lifespan analysis of repeat expression reveals age-dependent upregulation of HERV-K in the neurotypical human brain. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.17.24307184. [PMID: 38798538 PMCID: PMC11118647 DOI: 10.1101/2024.05.17.24307184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
DNA repetitive sequences (or repeats) comprise over 50% of the human genome and have a crucial regulatory role, specifically regulating transcription machinery. The human brain is the tissue with the highest detectable repeat expression and dysregulations on the repeat activity are related to several neurological and neurodegenerative disorders, as repeat-derived products can stimulate a pro-inflammatory response. Even so, it is unclear how repeat expression acts on the aging neurotypical brain. Here, we leverage a large postmortem transcriptome cohort spanning the human lifespan to assess global repeat expression in the neurotypical brain. We identified 21,696 differentially expressed repeats (DERs) that varied across seven age bins (Prenatal; 0-15; 16-29; 30-39; 40-49; 50-59; 60+) across the caudate nucleus (n=271), dorsolateral prefrontal cortex (n=304), and hippocampus (n=310). Interestingly, we found that long interspersed nuclear elements and long terminal repeats (LTRs) DERs were the most abundant repeat families when comparing infants to early adolescence (0-15) with older adults (60+). Of these differentially regulated LTRs, we identified 17 shared across all brain regions, including increased expression of HERV-K-int in older adult brains (60+). Co-expression analysis from each of the three brain regions also showed repeats from the HERV subfamily were intramodular hubs in its subnetworks. While we do not observe a strong global relationship between repeat expression and age, we identified HERV-K as a repeat signature associated with the aging neurotypical brain. Our study is the first global assessment of repeat expression in the neurotypical brain.
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Luqman-Fatah A, Miyoshi T. Human LINE-1 retrotransposons: impacts on the genome and regulation by host factors. Genes Genet Syst 2023; 98:121-154. [PMID: 36436935 DOI: 10.1266/ggs.22-00038] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Genome sequencing revealed that nearly half of the human genome is comprised of transposable elements. Although most of these elements have been rendered inactive due to mutations, full-length intact long interspersed element-1 (LINE-1 or L1) copies retain the ability to mobilize through RNA intermediates by a so-called "copy-and-paste" mechanism, termed retrotransposition. L1 is the only known autonomous mobile genetic element in the genome, and its retrotransposition contributes to inter- or intra-individual genetic variation within the human population. However, L1 retrotransposition also poses a threat to genome integrity due to gene disruption and chromosomal instability. Moreover, recent studies suggest that aberrant L1 expression can impact human health by causing diseases such as cancer and chronic inflammation that might lead to autoimmune disorders. To counteract these adverse effects, the host cells have evolved multiple layers of defense mechanisms at the epigenetic, RNA and protein levels. Intriguingly, several host factors have also been reported to facilitate L1 retrotransposition, suggesting that there is competition between negative and positive regulation of L1 by host factors. Here, we summarize the known host proteins that regulate L1 activity at different stages of the replication cycle and discuss how these factors modulate disease-associated phenotypes caused by L1.
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Affiliation(s)
- Ahmad Luqman-Fatah
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University
- Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University
| | - Tomoichiro Miyoshi
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University
- Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University
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3
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Copley KE, Shorter J. Repetitive elements in aging and neurodegeneration. Trends Genet 2023; 39:381-400. [PMID: 36935218 PMCID: PMC10121923 DOI: 10.1016/j.tig.2023.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/12/2023] [Accepted: 02/14/2023] [Indexed: 03/19/2023]
Abstract
Repetitive elements (REs), such as transposable elements (TEs) and satellites, comprise much of the genome. Here, we review how TEs and (peri)centromeric satellite DNA may contribute to aging and neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS). Alterations in RE expression, retrotransposition, and chromatin microenvironment may shorten lifespan, elicit neurodegeneration, and impair memory and movement. REs may cause these phenotypes via DNA damage, protein sequestration, insertional mutagenesis, and inflammation. We discuss several TE families, including gypsy, HERV-K, and HERV-W, and how TEs interact with various factors, including transactive response (TAR) DNA-binding protein 43 kDa (TDP-43) and the siRNA and piwi-interacting (pi)RNA systems. Studies of TEs in neurodegeneration have focused on Drosophila and, thus, further examination in mammals is needed. We suggest that therapeutic silencing of REs could help mitigate neurodegenerative disorders.
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Affiliation(s)
- Katie E Copley
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Neuroscience Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Neuroscience Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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4
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Rangel SC, da Silva MD, da Silva AL, dos Santos JDMB, Neves LM, Pedrosa A, Rodrigues FM, Trettel CDS, Furtado GE, de Barros MP, Bachi ALL, Romano CM, Nali LHDS. Human endogenous retroviruses and the inflammatory response: A vicious circle associated with health and illness. Front Immunol 2022; 13:1057791. [PMID: 36518758 PMCID: PMC9744114 DOI: 10.3389/fimmu.2022.1057791] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/31/2022] [Indexed: 11/24/2022] Open
Abstract
Human Endogenous Retroviruses (HERVs) are derived from ancient exogenous retroviral infections that have infected our ancestors' germline cells, underwent endogenization process, and were passed throughout the generations by retrotransposition and hereditary transmission. HERVs comprise 8% of the human genome and are critical for several physiological activities. Yet, HERVs reactivation is involved in pathological process as cancer and autoimmune diseases. In this review, we summarize the multiple aspects of HERVs' role within the human genome, as well as virological and molecular aspects, and their fusogenic property. We also discuss possibilities of how the HERVs are possibly transactivated and participate in modulating the inflammatory response in health conditions. An update on their role in several autoimmune, inflammatory, and aging-related diseases is also presented.
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Affiliation(s)
- Sara Coelho Rangel
- UNISA Research Center, Universidade Santo Amaro, Post-Graduation in Health Sciences, São Paulo, Brazil
| | | | - Amanda Lopes da Silva
- Laboratório de Virologia, Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, São Paulo, Brazil
| | | | - Lucas Melo Neves
- UNISA Research Center, Universidade Santo Amaro, Post-Graduation in Health Sciences, São Paulo, Brazil
| | - Ana Pedrosa
- CNC-Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, (3004-504), Coimbra, Portugal
| | | | - Caio dos Santos Trettel
- Interdisciplinary Program in Health Sciences, Institute of Physical Activity Sciences and Sports (ICAFE), Cruzeiro do Sul University, São Paulo, Brazil
| | - Guilherme Eustáquio Furtado
- Polytechnic Institute of Coimbra, Applied Research Institute, Rua da Misericórdia, Lagar dos Cortiços – S. Martinho do Bispo, Coimbra, Portugal
| | - Marcelo Paes de Barros
- Interdisciplinary Program in Health Sciences, Institute of Physical Activity Sciences and Sports (ICAFE), Cruzeiro do Sul University, São Paulo, Brazil
| | - André Luis Lacerda Bachi
- UNISA Research Center, Universidade Santo Amaro, Post-Graduation in Health Sciences, São Paulo, Brazil
| | - Camila Malta Romano
- Laboratório de Virologia, Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, São Paulo, Brazil,Hospital das Clínicas HCFMUSP (LIM52), Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Luiz Henrique Da Silva Nali
- UNISA Research Center, Universidade Santo Amaro, Post-Graduation in Health Sciences, São Paulo, Brazil,*Correspondence: Luiz Henrique Da Silva Nali, ;
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5
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She J, Du M, Xu Z, Jin Y, Li Y, Zhang D, Tao C, Chen J, Wang J, Yang E. The landscape of hervRNAs transcribed from human endogenous retroviruses across human body sites. Genome Biol 2022; 23:231. [PMID: 36329469 PMCID: PMC9632151 DOI: 10.1186/s13059-022-02804-w] [Citation(s) in RCA: 8] [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: 01/20/2022] [Accepted: 10/25/2022] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Human endogenous retroviruses (HERVs), the remnants of ancient retroviruses, account for 8% of the human genome, but most have lost their transcriptional abilities under physiological conditions. However, mounting evidence shows that several expressed HERVs do exert biological functions. Here, we systematically characterize physiologically expressed HERVs and examine whether they may give insight into the molecular fundamentals of human development and disease. RESULTS We systematically identify 13,889 expressed HERVs across normal body sites and demonstrate that they are expressed in body site-specific patterns and also by sex, ethnicity, and age. Analyzing cis-ERV-related quantitative trait loci, we find that 5435 hervRNAs are regulated by genetic variants. Combining this with a genome-wide association study, we elucidate that the dysregulation of expressed HERVs might be associated with various complex diseases, particularly neurodegenerative and psychiatric diseases. We further find that physiologically activated hervRNAs are associated with histone modifications rather than DNA demethylation. CONCLUSIONS Our results present a locus-specific landscape of physiologically expressed hervRNAs, which represent a hidden layer of genetic architecture in development and disease.
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Affiliation(s)
- Jianqi She
- Department of Microbiology & Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission of China, NHC Key Laboratory of Medical Immunology (Peking University), Beijing, 100191, China
- Department of Medical Bioinformatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Minghao Du
- Department of Microbiology & Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission of China, NHC Key Laboratory of Medical Immunology (Peking University), Beijing, 100191, China
- Department of Medical Bioinformatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Zhanzhan Xu
- Department of Medical Bioinformatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
- Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Yueqi Jin
- Department of Microbiology & Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission of China, NHC Key Laboratory of Medical Immunology (Peking University), Beijing, 100191, China
- Department of Medical Bioinformatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Yu Li
- Chinese Institute for Brain Research, Beijing, 102206, China
| | - Daoning Zhang
- Peking University First Hospital, Beijing, 100034, China
| | - Changyu Tao
- Department of Human Anatomy, Histology & Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Jian Chen
- Chinese Institute for Brain Research, Beijing, 102206, China
| | - Jiadong Wang
- Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Ence Yang
- Department of Microbiology & Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission of China, NHC Key Laboratory of Medical Immunology (Peking University), Beijing, 100191, China.
- Department of Medical Bioinformatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
- Chinese Institute for Brain Research, Beijing, 102206, China.
- Taizhou Medical New & Hi-tech Industrial Development Zone, Jiangsu, 225326, China.
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6
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Huitian G, Xiuai D, Chenglin Z, Xinfeng W, Yuanyuan L, Yanan S, Qihang C, Huiwen X. Transcriptional Analysis of Listeria monocytogenes Invasion of Macrophages. APPL BIOCHEM MICRO+ 2022. [DOI: 10.1134/s000368382203005x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Bu C, Wang Z, Ren Y, Chen D, Jiang SW. Syncytin-1 nonfusogenic activities modulate inflammation and contribute to preeclampsia pathogenesis. Cell Mol Life Sci 2022; 79:290. [PMID: 35536515 PMCID: PMC11073204 DOI: 10.1007/s00018-022-04294-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 03/23/2022] [Accepted: 04/06/2022] [Indexed: 11/03/2022]
Abstract
Maternal cellular and humoral immune responses to the allogeneic fetoplacental unit are a normal part of pregnancy adaptation. Overactive or dysregulated immune responses that often manifest as inflammation are considered a key element for the development of preeclampsia. Infiltration and activation of macrophages, nature killer cells, and T lymphocytes are frequently observed in the decidua and placenta associated with preeclampsia. In addition to local inflammation, systemic inflammatory changes including increased levels of TNF-α and interleukins (ILs) are detected in the maternal circulation. Syncytin-1 is an endogenous retroviral envelope protein that mediates the fusion of trophoblasts to form syncytiotrophoblasts, a cellular component carrying out most of placental barrier, exchange, and endocrine functions. In addition to these well-defined fusogenic functions that are known for their close association with preeclampsia, multiple studies indicated that syncytin-1 possesses nonfusogenic activities such as those for cell cycle and apoptosis regulation. Moreover, syncytin-1 expressed by trophoblasts and various types of immune cells may participate in regulation of inflammation in preeclamptic placenta and decidua. This review concentrates on the triangular relationship among inflammation, syncytin-1 nonfusogenic functions, and preeclampsia pathogenesis. Data regarding the reciprocal modulations of inflammation and poor vascularization/hypoxia are summarized. The impacts of syncytin-A (the mouse counterpart of human syncytin-1) gene knockout on placental vascularization and their implications for preeclampsia are discussed. Syncytin-1 expression in immune cells and its significance for inflammation are analyzed in the context of preeclampsia development. Finally, the involvements of syncytin-1 nonfusogenic activities in neuroinflammation and multiple sclerosis are compared to findings from preeclampsia.
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Affiliation(s)
- Chaozhi Bu
- Center of Reproductive Medicine, State Key Laboratory of Reproductive Medicine, Research Institute for Reproductive Health and Genetic Diseases, The Affiliated Wuxi Maternity and Child Health Care Hospital of Nanjing Medical University, Wuxi, 214002, China
| | - Zhiwei Wang
- Center of Reproductive Medicine, State Key Laboratory of Reproductive Medicine, Research Institute for Reproductive Health and Genetic Diseases, The Affiliated Wuxi Maternity and Child Health Care Hospital of Nanjing Medical University, Wuxi, 214002, China
- Center of Prenatal Diagnosis, Lianyungang Maternal and Child Health Hospital, Lianyungang, 222000, Jiangsu, China
| | - Yongwei Ren
- Center of Reproductive Medicine, State Key Laboratory of Reproductive Medicine, Research Institute for Reproductive Health and Genetic Diseases, The Affiliated Wuxi Maternity and Child Health Care Hospital of Nanjing Medical University, Wuxi, 214002, China
| | - Daozhen Chen
- Research Institute for Reproductive Health and Genetic Diseases, The Affiliated Wuxi Maternity and Child Health Care Hospital of Nanjing Medical University, Wuxi, 214002, China.
| | - Shi-Wen Jiang
- Center of Reproductive Medicine, State Key Laboratory of Reproductive Medicine, Research Institute for Reproductive Health and Genetic Diseases, The Affiliated Wuxi Maternity and Child Health Care Hospital of Nanjing Medical University, Wuxi, 214002, China.
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8
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Elkjaer ML, Röttger R, Baumbach J, Illes Z. A Systematic Review of Tissue and Single Cell Transcriptome/Proteome Studies of the Brain in Multiple Sclerosis. Front Immunol 2022; 13:761225. [PMID: 35309325 PMCID: PMC8924618 DOI: 10.3389/fimmu.2022.761225] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 01/28/2022] [Indexed: 11/27/2022] Open
Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating and degenerative disease of the central nervous system (CNS). Although inflammatory responses are efficiently treated, therapies for progression are scarce and suboptimal, and biomarkers to predict the disease course are insufficient. Cure or preventive measures for MS require knowledge of core pathological events at the site of the tissue damage. Novelties in systems biology have emerged and paved the way for a more fine-grained understanding of key pathological pathways within the CNS, but they have also raised questions still without answers. Here, we systemically review the power of tissue and single-cell/nucleus CNS omics and discuss major gaps of integration into the clinical practice. Systemic search identified 49 transcriptome and 11 proteome studies of the CNS from 1997 till October 2021. Pioneering molecular discoveries indicate that MS affects the whole brain and all resident cell types. Despite inconsistency of results, studies imply increase in transcripts/proteins of semaphorins, heat shock proteins, myelin proteins, apolipoproteins and HLAs. Different lesions are characterized by distinct astrocytic and microglial polarization, altered oligodendrogenesis, and changes in specific neuronal subtypes. In all white matter lesion types, CXCL12, SCD, CD163 are highly expressed, and STAT6- and TGFβ-signaling are increased. In the grey matter lesions, TNF-signaling seems to drive cell death, and especially CUX2-expressing neurons may be susceptible to neurodegeneration. The vast heterogeneity at both cellular and lesional levels may underlie the clinical heterogeneity of MS, and it may be more complex than the current disease phenotyping in the clinical practice. Systems biology has not solved the mystery of MS, but it has discovered multiple molecules and networks potentially contributing to the pathogenesis. However, these results are mostly descriptive; focused functional studies of the molecular changes may open up for a better interpretation. Guidelines for acceptable quality or awareness of results from low quality data, and standardized computational and biological pipelines may help to overcome limited tissue availability and the “snap shot” problem of omics. These may help in identifying core pathological events and point in directions for focus in clinical prevention.
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Affiliation(s)
- Maria L Elkjaer
- Department of Neurology, Odense University Hospital, Odense, Denmark.,Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.,Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Richard Röttger
- Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark
| | - Jan Baumbach
- Chair of Computational Systems Biology, University of Hamburg, Hamburg, Germany
| | - Zsolt Illes
- Department of Neurology, Odense University Hospital, Odense, Denmark.,Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.,Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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9
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Pérez-Pérez S, Domínguez-Mozo MI, García-Martínez MÁ, Ballester-González R, Nieto-Gañán I, Arroyo R, Alvarez-Lafuente R. Epstein-Barr Virus Load Correlates with Multiple Sclerosis-Associated Retrovirus Envelope Expression. Biomedicines 2022; 10:biomedicines10020387. [PMID: 35203596 PMCID: PMC8962350 DOI: 10.3390/biomedicines10020387] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/28/2022] [Accepted: 02/01/2022] [Indexed: 02/01/2023] Open
Abstract
pHERV-W ENV and syncytin-1, the envelope proteins of the human endogenous retrovirus W family (HERV-W), have been proposed as etiological factors for MS development. In addition, herpesviruses, such as the Epstein-Barr virus (EBV) and the human herpesvirus 6A/B (HHV-6A/B), have been also strongly associated with the disease. This work aims to study the possible link between viral loads and antibody titers against EBV and HHV-6A/B and the pHERV-W ENV/syncytin-1 protein/gene expression. For this purpose, we conducted a 12-month longitudinal study involving 98 RRMS patients. Peripheral blood samples were obtained from each patient. Serum antibody titers against EBV and HHV-6A/B were determined by ELISA, while viral loads were analyzed using qPCR. HLA MS-related alleles were also genotyped. pHERV-W ENV/syncytin-1 protein and gene expression levels in immune cells were assessed by flow cytometry and qPCR, respectively. We found that the 12-month variation of the pHERV-W ENV gene expression levels positively correlated with the variation of the EBV viral load, especially in those patients with high baseline EBV loads. Therefore, these results could support previous studies pointing to the transactivation of pHERV-W ENV by EBV. However, further studies are needed to better understand this possible relationship.
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Affiliation(s)
- Silvia Pérez-Pérez
- Environmental Factors in Degenerative Diseases Research Group, Hospital Clínico San Carlos, IdISSC, 28040 Madrid, Spain; (S.P.-P.); (M.I.D.-M.); (M.Á.G.-M.)
| | - María Inmaculada Domínguez-Mozo
- Environmental Factors in Degenerative Diseases Research Group, Hospital Clínico San Carlos, IdISSC, 28040 Madrid, Spain; (S.P.-P.); (M.I.D.-M.); (M.Á.G.-M.)
| | - María Ángel García-Martínez
- Environmental Factors in Degenerative Diseases Research Group, Hospital Clínico San Carlos, IdISSC, 28040 Madrid, Spain; (S.P.-P.); (M.I.D.-M.); (M.Á.G.-M.)
| | - Rubén Ballester-González
- Immunology Department, Hospital Universitario Ramón y Cajal, 28034 Madrid, Spain; (R.B.-G.); (I.N.-G.)
| | - Israel Nieto-Gañán
- Immunology Department, Hospital Universitario Ramón y Cajal, 28034 Madrid, Spain; (R.B.-G.); (I.N.-G.)
| | - Rafael Arroyo
- Neurology Department, Hospital Universitario Quironsalud Madrid, 28223 Madrid, Spain;
| | - Roberto Alvarez-Lafuente
- Environmental Factors in Degenerative Diseases Research Group, Hospital Clínico San Carlos, IdISSC, 28040 Madrid, Spain; (S.P.-P.); (M.I.D.-M.); (M.Á.G.-M.)
- Correspondence:
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10
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Ramirez P, Zuniga G, Sun W, Beckmann A, Ochoa E, DeVos SL, Hyman B, Chiu G, Roy ER, Cao W, Orr M, Buggia-Prevot V, Ray WJ, Frost B. Pathogenic tau accelerates aging-associated activation of transposable elements in the mouse central nervous system. Prog Neurobiol 2022; 208:102181. [PMID: 34670118 PMCID: PMC8712387 DOI: 10.1016/j.pneurobio.2021.102181] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/05/2021] [Accepted: 10/12/2021] [Indexed: 01/03/2023]
Abstract
Transposable elements comprise almost half of the mammalian genome. A growing body of evidence suggests that transposable element dysregulation accompanies brain aging and neurodegenerative disorders, and that transposable element activation is neurotoxic. Recent studies have identified links between pathogenic forms of tau, a protein that accumulates in Alzheimer's disease and related "tauopathies," and transposable element-induced neurotoxicity. Starting with transcriptomic analyses, we find that age- and tau-induced transposable element activation occurs in the mouse brain. Among transposable elements that are activated at the RNA level in the context of brain aging and tauopathy, we find that the endogenous retrovirus (ERV) class of retrotransposons is particularly enriched. We show that protein encoded by Intracisternal A-particle, a highly active mouse ERV, is elevated in brains of tau transgenic mice. Using two complementary approaches, we find that brains of tau transgenic mice contain increased DNA copy number of transposable elements, raising the possibility that these elements actively retrotranspose in the context of tauopathy. Taken together, our study lays the groundwork for future mechanistic studies focused on transposable element regulation in the aging mouse brain and in mouse models of tauopathy and provides support for ongoing therapeutic efforts targeting transposable element activation in patients with Alzheimer's disease.
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Affiliation(s)
- Paulino Ramirez
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, Texas,Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, Texas,Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
| | - Gabrielle Zuniga
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, Texas,Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, Texas,Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
| | - Wenyan Sun
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, Texas,Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, Texas,Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
| | - Adrian Beckmann
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, Texas,Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, Texas,Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
| | - Elizabeth Ochoa
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, Texas,Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, Texas,Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
| | - Sarah L. DeVos
- Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Bradley Hyman
- Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Gabriel Chiu
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX
| | - Ethan R. Roy
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX
| | - Wei Cao
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX
| | - Miranda Orr
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC,WG Hefner VA Medical Center, Salisbury, NC
| | - Virginie Buggia-Prevot
- The Neurodegeneration Consortium, Therapeutics Discovery Division, University of Texas MD Anderson Cancer Center, Houston, TX
| | - William J. Ray
- The Neurodegeneration Consortium, Therapeutics Discovery Division, University of Texas MD Anderson Cancer Center, Houston, TX
| | - Bess Frost
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, Texas,Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, Texas,Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas,Corresponding Author and Lead Contact: Bess Frost, Ph.D., Associate Professor, 4939 Charles Katz, Barshop Institute, rm 1041, University of Texas Health San Antonio, San Antonio, TX 78229, Phone: 210-562-5037,
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11
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Pérez-Pérez S, Domínguez-Mozo MI, García-Martínez MÁ, García-Frontini MC, Villarrubia N, Costa-Frossard L, Villar LM, Arroyo R, Álvarez-Lafuente R. Anti-Human Herpesvirus 6 A/B Antibodies Titers Correlate With Multiple Sclerosis-Associated Retrovirus Envelope Expression. Front Immunol 2021; 12:798003. [PMID: 34912348 PMCID: PMC8666430 DOI: 10.3389/fimmu.2021.798003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 11/11/2021] [Indexed: 12/23/2022] Open
Abstract
Human endogenous retrovirus W family envelope proteins (pHERV-W ENV/syncytin-1) have been repeatedly associated with multiple sclerosis (MS). Here, we have focused on the study of pHERV-W ENV/syncytin-1 expression levels in MS patients (relapsing and progressive forms) and in healthy donors (HD) and on exploring their possible relationship with Epstein-Barr virus (EBV) and human herpesvirus-6A/B (HHV-6A/B). We included blood samples from 101 MS patients and 37 HD to analyze antiviral antibody titers by ELISA and pHERV-W ENV/syncytin-1 expression levels by flow cytometry as well as by qPCR. Patients with relapsing MS forms showed significantly higher pHERV-W ENV/syncytin-1 protein and gene expression levels than HD. Progressive MS patients also showed significantly higher protein and gene expression levels than both HD and relapsing MS patients. Regarding antiviral antibodies titers, anti-HHV-6A/B IgM levels were positively correlated with pHERV-W ENV/syncytin-1 protein expression levels in patients with relapsing MS, while in the progressive forms patients this correlation was found with anti-HHVA/B IgG levels. Therefore, pHERV-W ENV could be involved in MS pathogenesis, playing a role in relapsing and progressive forms. Besides, anti-HHV-6A/B antibodies positively correlated with pHERV-W ENV expression. Further studies are needed to better understand this possible relationship.
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Affiliation(s)
- Silvia Pérez-Pérez
- Environmental Factors in Degenerative Diseases Research Group, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - María I. Domínguez-Mozo
- Environmental Factors in Degenerative Diseases Research Group, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - M. Ángel García-Martínez
- Environmental Factors in Degenerative Diseases Research Group, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - M. Celeste García-Frontini
- Environmental Factors in Degenerative Diseases Research Group, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Noelia Villarrubia
- Immunology Department, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | | | - Luisa M. Villar
- Immunology Department, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Rafael Arroyo
- Neurology Department, Hospital Universitario Quironsalud Madrid, Madrid, Spain
| | - Roberto Álvarez-Lafuente
- Environmental Factors in Degenerative Diseases Research Group, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
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12
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Nali LH, Olival GS, Montenegro H, da Silva IT, Dias-Neto E, Naya H, Spangenberg L, Penalva-de-Oliveira AC, Romano CM. Human endogenous retrovirus and multiple sclerosis: A review and transcriptome findings. Mult Scler Relat Disord 2021; 57:103383. [PMID: 34922254 DOI: 10.1016/j.msard.2021.103383] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 10/15/2021] [Accepted: 11/05/2021] [Indexed: 12/14/2022]
Abstract
Multiple Sclerosis is an autoimmune disease with an unknown etiology. Both genetic and environmental factors are believed to trigger MS autoimmunity. Among the environmental factors, infectious agents have been extensively investigated, and the Human Endogenous Retroviruses (HERVs), especially HERV-W, are believed to be associated with MS pathogenesis. HERVs are derived from ancestral infections and comprise around 8% of the human genome. Although most HERVs are silenced, retroviral genes may be expressed with virion formation. There is extensive evidence of the relationship between HERV-W and MS, including higher levels of HERV-W expression in MS patients, HERV-W protein detection in MS plaques, and the HERV-W env protein inducing an inflammatory response in in vitro and in vivo models. Here we discuss possible links of HERVs and the pathogenesis of MS and present new data regarding the diversity of HERVs expression in samples derived from MS patients.
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Affiliation(s)
- Luiz H Nali
- Laboratório de Virologia, Instituto de Medicina Tropical de São Paulo, LIM-52 (LIMHC) Universidade de São Paulo, Rua Dr. Enéas de Carvalho Aguiar, 470, São Paulo 05403-000, Brazil; Post-graduation Program in Health Sciences, Santo Amaro University, Rua Prof. Enéas de Siqueira Neto, 340, São Paulo 04829-300, Brazil
| | - Guilherme S Olival
- Departamento de Neurologia Santa Casa de Misericórdia de São Paulo, R. Dr. Cesário Mota Júnior, 112, São Paulo 01221-020 Brazil
| | | | - Israel T da Silva
- Laboratory of Medical Genomics, A.C. Camargo Cancer Center, São Paulo 01525-001, Brazil
| | - Emmanuel Dias-Neto
- Laboratory of Medical Genomics, A.C. Camargo Cancer Center, São Paulo 01525-001, Brazil; Laboratory of Neurosciences (LIM-27), Institute of Psychiatry, São Paulo Medical School, University of São Paulo, São Paulo, Brazil
| | - Hugo Naya
- Unidad de Bioinformática Institut Pasteur de Montevideo, Mataojo 2020, CP11400 Montevideo, Uruguay; Departamento de Producción Animal y Pasturas, Facultad de Agronomía, Universidad de la República, Av. Gral. Eugenio Garzón 780, CP12900 Montevideo, Uruguay
| | - Lucia Spangenberg
- Unidad de Bioinformática Institut Pasteur de Montevideo, Mataojo 2020, CP11400 Montevideo, Uruguay
| | - Augusto C Penalva-de-Oliveira
- Departamento de Neurologia Santa Casa de Misericórdia de São Paulo, R. Dr. Cesário Mota Júnior, 112, São Paulo 01221-020 Brazil; Departamento de Neurologia, Instituto de Infectologia Emilio Ribas, Avenida Doutor Arnaldo, 165, São Paulo 01246-900, Brazil
| | - Camila M Romano
- Laboratório de Virologia, Instituto de Medicina Tropical de São Paulo, LIM-52 (LIMHC) Universidade de São Paulo, Rua Dr. Enéas de Carvalho Aguiar, 470, São Paulo 05403-000, Brazil; Hospital das Clinicas HCFMUSP (LIM52), Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil.
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13
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Tokuyama M, Gunn BM, Venkataraman A, Kong Y, Kang I, Rakib T, Townsend MJ, Costenbader KH, Alter G, Iwasaki A. Antibodies against human endogenous retrovirus K102 envelope activate neutrophils in systemic lupus erythematosus. J Exp Med 2021; 218:212176. [PMID: 34019642 PMCID: PMC8144942 DOI: 10.1084/jem.20191766] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 03/08/2021] [Accepted: 04/23/2021] [Indexed: 01/03/2023] Open
Abstract
Neutrophil activation and the formation of neutrophil extracellular traps (NETs) are hallmarks of innate immune activation in systemic lupus erythematosus (SLE). Here we report that the expression of an endogenous retrovirus (ERV) locus ERV-K102, encoding an envelope protein, was significantly elevated in SLE patient blood and correlated with autoantibody levels and higher interferon status. Induction of ERV-K102 in SLE negatively correlated with the expression of epigenetic silencing factors. Anti-ERV-K102 IgG levels in SLE plasma correlated with higher interferon stimulated gene expression, and further promoted enhanced neutrophil phagocytosis of ERV-K102 envelope protein through immune complex formation. Finally, phagocytosis of ERV-K102 immune complexes resulted in the formation of NETs consisting of DNA, neutrophil elastase, and citrullinated histone H3. Together, we identified an immunostimulatory ERV-K envelope protein that in an immune complex with SLE IgG is capable of activating neutrophils.
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Affiliation(s)
- Maria Tokuyama
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT
| | - Bronwyn M Gunn
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University, Cambridge, MA
| | - Arvind Venkataraman
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT
| | - Yong Kong
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT
| | - Insoo Kang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT
| | - Tasfia Rakib
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT
| | | | | | - Galit Alter
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University, Cambridge, MA
| | - Akiko Iwasaki
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT.,Howard Hughes Medical Institute, Chevy Chase, MD
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14
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Macías-Redondo S, Strunk M, Cebollada-Solanas A, Ara JR, Martín J, Schoorlemmer J. Upregulation of selected HERVW loci in multiple sclerosis. Mob DNA 2021; 12:18. [PMID: 34187540 PMCID: PMC8243764 DOI: 10.1186/s13100-021-00243-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 06/01/2021] [Indexed: 01/08/2023] Open
Affiliation(s)
- Sofía Macías-Redondo
- Instituto Aragonés de Ciencias de la Salud (IACS), c/Juan Bosco 13, 50009, Zaragoza, Spain
| | - Mark Strunk
- Sequencing and Functional Genomics, Aragon Biomedical Research Center (CIBA), Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, Spain
| | - Alberto Cebollada-Solanas
- Aragon Biomedical Research Center (CIBA), Instituto Aragonés de Ciencias de la Salud (IACS), Unidad de Biocomputación, Zaragoza, Spain
| | - José-Ramón Ara
- Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain.,Department of Neurology, University Hospital Miguel Servet, Zaragoza, Spain
| | - Jesús Martín
- Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain.,Department of Neurology, University Hospital Miguel Servet, Zaragoza, Spain
| | - Jon Schoorlemmer
- Instituto Aragonés de Ciencias de la Salud (IACS), c/Juan Bosco 13, 50009, Zaragoza, Spain. .,ARAID Foundation, Avda. de Ranillas 1-D, 50018, Zaragoza, Spain. .,Placental pathophysiology and fetal programming research group del IISA, c/Juan Bosco 13, 50009, Zaragoza, Spain.
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15
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Pisano MP, Grandi N, Tramontano E. Human Endogenous Retroviruses (HERVs) and Mammalian Apparent LTRs Retrotransposons (MaLRs) Are Dynamically Modulated in Different Stages of Immunity. BIOLOGY 2021; 10:biology10050405. [PMID: 34062989 PMCID: PMC8147956 DOI: 10.3390/biology10050405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/26/2021] [Accepted: 04/30/2021] [Indexed: 12/25/2022]
Abstract
Human Endogenous retroviruses (HERVs) and Mammalian Apparent LTRs Retrotransposons (MaLRs) are remnants of ancient retroviral infections that represent a large fraction of our genome. The HERV and MaLR transcriptional activity is regulated in developmental stages, adult tissues, and pathological conditions. In this work, we used a bioinformatics approach based on RNA-sequencing (RNA-seq) to study the expression and modulation of HERVs and MaLR in a scenario of activation of the immune response. We analyzed transcriptome data from subjects before and after the administration of an inactivated vaccine against the Hantaan orthohantavirus, the causative agent of Korean hemorrhagic fever, to investigate the HERV and MaLR expression and differential expression in response to the administration of the vaccine. Specifically, we described the HERV transcriptome in PBMCs and identified HERV and MaLR loci differentially expressed after the 2nd, 3rd, and 4th inactivated vaccine administrations. We found that the expression of 545 HERV and MaLR elements increased in response to the vaccine and that the activation of several individual HERV and MaLR loci is specific for each vaccine administration and correlated to different genes and immune-related pathways.
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16
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Padmanabhan Nair V, Liu H, Ciceri G, Jungverdorben J, Frishman G, Tchieu J, Cederquist GY, Rothenaigner I, Schorpp K, Klepper L, Walsh RM, Kim TW, Cornacchia D, Ruepp A, Mayer J, Hadian K, Frishman D, Studer L, Vincendeau M. Activation of HERV-K(HML-2) disrupts cortical patterning and neuronal differentiation by increasing NTRK3. Cell Stem Cell 2021; 28:1566-1581.e8. [PMID: 33951478 DOI: 10.1016/j.stem.2021.04.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 03/05/2021] [Accepted: 04/12/2021] [Indexed: 12/20/2022]
Abstract
The biological function and disease association of human endogenous retroviruses (HERVs) are largely elusive. HERV-K(HML-2) has been associated with neurotoxicity, but there is no clear understanding of its role or mechanistic basis. We addressed the physiological functions of HERV-K(HML-2) in neuronal differentiation using CRISPR engineering to activate or repress its expression levels in a human-pluripotent-stem-cell-based system. We found that elevated HERV-K(HML-2) transcription is detrimental for the development and function of cortical neurons. These effects are cell-type-specific, as dopaminergic neurons are unaffected. Moreover, high HERV-K(HML-2) transcription alters cortical layer formation in forebrain organoids. HERV-K(HML-2) transcriptional activation leads to hyperactivation of NTRK3 expression and other neurodegeneration-related genes. Direct activation of NTRK3 phenotypically resembles HERV-K(HML-2) induction, and reducing NTRK3 levels in context of HERV-K(HML-2) induction restores cortical neuron differentiation. Hence, these findings unravel a cell-type-specific role for HERV-K(HML-2) in cortical neuron development.
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Affiliation(s)
| | - Hengyuan Liu
- Department of Genome-Oriented Bioinformatics, Technical University Munich, Munich, Germany
| | - Gabriele Ciceri
- Developmental Biology and Center for Stem Cell Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Johannes Jungverdorben
- Developmental Biology and Center for Stem Cell Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Goar Frishman
- Institute of Experimental Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Jason Tchieu
- Developmental Biology and Center for Stem Cell Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Gustav Y Cederquist
- Developmental Biology and Center for Stem Cell Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ina Rothenaigner
- Assay Development and Screening Platform, Helmholtz Zentrum München, Neuherberg, Germany
| | - Kenji Schorpp
- Assay Development and Screening Platform, Helmholtz Zentrum München, Neuherberg, Germany
| | - Lena Klepper
- Institute of Virology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Ryan M Walsh
- Developmental Biology and Center for Stem Cell Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Tae Wan Kim
- Developmental Biology and Center for Stem Cell Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Daniela Cornacchia
- Developmental Biology and Center for Stem Cell Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Andreas Ruepp
- Institute of Experimental Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Jens Mayer
- Institute of Human Genetics, University of Saarland, Homburg, Germany
| | - Kamyar Hadian
- Assay Development and Screening Platform, Helmholtz Zentrum München, Neuherberg, Germany
| | - Dmitrij Frishman
- Department of Genome-Oriented Bioinformatics, Technical University Munich, Munich, Germany
| | - Lorenz Studer
- Developmental Biology and Center for Stem Cell Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Michelle Vincendeau
- Institute of Virology, Helmholtz Zentrum München, Neuherberg, Germany; Developmental Biology and Center for Stem Cell Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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17
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Elkjaer ML, Frisch T, Tonazzolli A, Röttger R, Reynolds R, Baumbach J, Illes Z. Unbiased examination of genome-wide human endogenous retrovirus transcripts in MS brain lesions. Mult Scler 2021; 27:1829-1837. [PMID: 33464158 DOI: 10.1177/1352458520987269] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Human endogenous retrovirus (HERV) expression in multiple sclerosis (MS) brain lesions may contribute to chronic inflammation, but expression of genome-wide HERVs in different MS lesions is unknown. OBJECTIVE We examined the HERV expression landscape in different MS lesions compared to control brains. METHODS Transcripts from 71 MS brain samples and 25 control WM were obtained by next-generation RNA sequencing and mapped against HERV transcripts across the human genome. Differential expression of mapped HERV-W and HERV-H reads between MS lesion types and controls was analysed. RESULTS Out of 6.38 billion high-quality paired end reads, 174 million reads (2.73%) mapped to HERV transcripts. There was no difference in HERVs expression level between MS and control brains, but HERV-W transcripts were significantly reduced in chronic active lesions. Of the four HERV-W transcripts exclusively present in MS, ERV3633503 located on chromosome 7q21.13 close to the MS genetic risk locus had the highest number of reads. In the HERV-H family, 75% of transcripts located to nearby 7q21-22 were overrepresented in MS, and ERV3643914 was expressed more than 16 times in MS compared to control brains. CONCLUSION Novel HERV-W and HERV-H transcripts located at chromosome 7 regions were uniquely expressed in MS lesions, indicating their potential role in brain lesion evolution.
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Affiliation(s)
- Maria L Elkjaer
- Department of Neurology, Odense University Hospital, Odense, Denmark/Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark/Neurobiology Research Unit, Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Tobias Frisch
- Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark
| | - Arianna Tonazzolli
- Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark/Department of Cellular, Computational and Integrative Biology, University of Trento, Trento, Italy
| | - Richard Röttger
- Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark
| | - Richard Reynolds
- Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Jan Baumbach
- TUM School of Life Sciences, Technical University of Munich, Munich, Germany
| | - Zsolt Illes
- Department of Neurology, Odense University Hospital, Odense, Denmark/Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark/Neurobiology Research Unit, Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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18
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Gröger V, Emmer A, Staege MS, Cynis H. Endogenous Retroviruses in Nervous System Disorders. Pharmaceuticals (Basel) 2021; 14:ph14010070. [PMID: 33467098 PMCID: PMC7829834 DOI: 10.3390/ph14010070] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 02/06/2023] Open
Abstract
Human endogenous retroviruses (HERV) have been implicated in the pathogenesis of several nervous system disorders including multiple sclerosis and amyotrophic lateral sclerosis. The toxicity of HERV-derived RNAs and proteins for neuronal cells has been demonstrated. The involvement of HERV in the pathogenesis of currently incurable diseases might offer new treatment strategies based on the inhibition of HERV activities by small molecules or therapeutic antibodies.
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Affiliation(s)
- Victoria Gröger
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, 06120 Halle (Saale), Germany;
| | - Alexander Emmer
- Department of Neurology, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany;
| | - Martin S. Staege
- Department of Surgical and Conservative Pediatrics and Adolescent Medicine, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
- Correspondence: (M.S.S.); (H.C.); Tel.: +49-345-557-7280 (M.S.S.); +49-345-13142835 (H.C.)
| | - Holger Cynis
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, 06120 Halle (Saale), Germany;
- Correspondence: (M.S.S.); (H.C.); Tel.: +49-345-557-7280 (M.S.S.); +49-345-13142835 (H.C.)
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19
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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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20
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Evans TA, Erwin JA. Retroelement-derived RNA and its role in the brain. Semin Cell Dev Biol 2020; 114:68-80. [PMID: 33229216 DOI: 10.1016/j.semcdb.2020.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 10/20/2020] [Accepted: 11/04/2020] [Indexed: 12/17/2022]
Abstract
Comprising ~40% of the human genome, retroelements are mobile genetic elements which are transcribed into RNA, then reverse-transcribed into DNA and inserted into a new site in the genome. Retroelements are referred to as "genetic parasites", residing among host genes and relying on host machinery for transcription and evolutionary propagation. The healthy brain has the highest expression of retroelement-derived sequences compared to other somatic tissue, which leads to the question: how does retroelement-derived RNA influence human traits and cellular states? While the functional importance of upregulating retroelement expression in the brain is an active area of research, RNA species derived from retroelements influence both self- and host gene expression by contributing to chromatin remodeling, alternative splicing, somatic mosaicism and translational repression. Here, we review the emerging evidence that the functional importance of RNA derived from retroelements is multifaceted. Retroelements can influence organismal states through the seeding of epigenetic states in chromatin, the production of structured RNA and even catalytically active ribozymes, the generation of cytoplasmic ssDNA and RNA/DNA hybrids, the production of viral-like proteins, and the generation of somatic mutations. Comparative sequencing suggests that retroelements can contribute to intraspecies variation through these mechanisms to alter transcript identity and abundance. In humans, an increasing number of neurodevelopmental and neurodegenerative conditions are associated with dysregulated retroelements, including Aicardi-Goutieres syndrome (AGS), Rett syndrome (RTT), Amyotrophic Lateral Sclerosis (ALS), Alzheimer's disease (AD), multiple sclerosis (MS), schizophrenia (SZ), and aging. Taken together, these concepts suggest a larger functional role for RNA derived from retroelements. This review aims to define retroelement-derived RNA, discuss how it impacts the mammalian genome, as well as summarize data supporting phenotypic consequences of this unique RNA subset in the brain.
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Affiliation(s)
- Taylor A Evans
- Lieber Institute for Brain Development, Baltimore, MD, USA; Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Jennifer Ann Erwin
- Lieber Institute for Brain Development, Baltimore, MD, USA; Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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21
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Posttranscriptional regulation of human endogenous retroviruses by RNA-binding motif protein 4, RBM4. Proc Natl Acad Sci U S A 2020; 117:26520-26530. [PMID: 33020268 DOI: 10.1073/pnas.2005237117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The human genome encodes for over 1,500 RNA-binding proteins (RBPs), which coordinate regulatory events on RNA transcripts. Most studies of RBPs have concentrated on their action on host protein-encoding mRNAs, which constitute a minority of the transcriptome. A widely neglected subset of our transcriptome derives from integrated retroviral elements, termed endogenous retroviruses (ERVs), that comprise ∼8% of the human genome. Some ERVs have been shown to be transcribed under physiological and pathological conditions, suggesting that sophisticated regulatory mechanisms to coordinate and prevent their ectopic expression exist. However, it is unknown how broadly RBPs and ERV transcripts directly interact to provide a posttranscriptional layer of regulation. Here, we implemented a computational pipeline to determine the correlation of expression between individual RBPs and ERVs from single-cell or bulk RNA-sequencing data. One of our top candidates for an RBP negatively regulating ERV expression was RNA-binding motif protein 4 (RBM4). We used photoactivatable ribonucleoside-enhanced cross-linking and immunoprecipitation to demonstrate that RBM4 indeed bound ERV transcripts at CGG consensus elements. Loss of RBM4 resulted in an elevated transcript level of bound ERVs of the HERV-K and -H families, as well as increased expression of HERV-K envelope protein. We pinpointed RBM4 regulation of HERV-K to a CGG-containing element that is conserved in the LTRs of HERV-K-10, -K-11, and -K-20, and validated the functionality of this site using reporter assays. In summary, we systematically identified RBPs that may regulate ERV function and demonstrate a role for RBM4 in controlling ERV expression.
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Dechaumes A, Bertin A, Sane F, Levet S, Varghese J, Charvet B, Gmyr V, Kerr-Conte J, Pierquin J, Arunkumar G, Pattou F, Perron H, Hober D. Coxsackievirus-B4 Infection Can Induce the Expression of Human Endogenous Retrovirus W in Primary Cells. Microorganisms 2020; 8:E1335. [PMID: 32883004 PMCID: PMC7563422 DOI: 10.3390/microorganisms8091335] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 02/06/2023] Open
Abstract
Human Endogenous Retrovirus W Envelope (HERV-W ENV) mRNA or protein can be found in peripheral blood mononuclear cells (PBMCs) and exocrine pancreas of patients with type 1 diabetes (T1D). Further, previous observations have shown an association between enteroviral infection and development of T1D; specifically, coxsackievirus-B (CV-B) has been detected in the blood and pancreas of patients with T1D. Notably, viruses can activate HERV-W expression. Hence, we evaluated the effect of CV-B4 infection on HERV-W ENV mRNA expression. Primary human pancreatic ductal cells were obtained from five brain-dead donors. In the pancreatic cells of three donors, the HERV-W ENV mRNA level measured using RT-qPCR was upregulated upon CV-B4 infection. The HERV-W ENV protein was detected in the infected cells using the immunoblot assay. In human PBMCs inoculated with CV-B4 or when CV-B4 was incubated with an enhancing serum, the HERV-W ENV mRNA level was higher than the background RNA level. In monocyte-derived macrophages obtained from 5 of 13 donors, the HERV-W ENV mRNA level was higher in cultures inoculated with CV-B4 than in the control. Therefore, CV-B4 can upregulate or induce the transcription of a certain HERV-W ENV copy (or copies) in primary cell cultures, such as monocytes, macrophages, and pancreatic cells.
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Affiliation(s)
- Arthur Dechaumes
- Laboratoire de Virologie ULR3610 Univ Lille, CHU Lille, 59000 Lille, France; (A.D.); (A.B.); (F.S.); (J.V.)
| | - Antoine Bertin
- Laboratoire de Virologie ULR3610 Univ Lille, CHU Lille, 59000 Lille, France; (A.D.); (A.B.); (F.S.); (J.V.)
| | - Famara Sane
- Laboratoire de Virologie ULR3610 Univ Lille, CHU Lille, 59000 Lille, France; (A.D.); (A.B.); (F.S.); (J.V.)
| | - Sandrine Levet
- Geneuro Innovation, 69008 Lyon, France; (S.L.); (B.C.); (J.P.); (H.P.)
| | - Jennifer Varghese
- Laboratoire de Virologie ULR3610 Univ Lille, CHU Lille, 59000 Lille, France; (A.D.); (A.B.); (F.S.); (J.V.)
- Manipal Institute of Virology, Manipal Academy of Higher Education, Karnataka 576104, India;
| | - Benjamin Charvet
- Geneuro Innovation, 69008 Lyon, France; (S.L.); (B.C.); (J.P.); (H.P.)
| | - Valéry Gmyr
- U1190 Univ Lille, Inserm, CHU Lille, European Genomic Institute for Diabetes, 59000 Lille, France; (V.G.); (J.K.-C.); (F.P.)
| | - Julie Kerr-Conte
- U1190 Univ Lille, Inserm, CHU Lille, European Genomic Institute for Diabetes, 59000 Lille, France; (V.G.); (J.K.-C.); (F.P.)
| | - Justine Pierquin
- Geneuro Innovation, 69008 Lyon, France; (S.L.); (B.C.); (J.P.); (H.P.)
| | | | - François Pattou
- U1190 Univ Lille, Inserm, CHU Lille, European Genomic Institute for Diabetes, 59000 Lille, France; (V.G.); (J.K.-C.); (F.P.)
| | - Hervé Perron
- Geneuro Innovation, 69008 Lyon, France; (S.L.); (B.C.); (J.P.); (H.P.)
- Geneuro SA, 1228 Geneva, Switzerland
- Faculté de Médecine Laënnec, Université de Lyon, 69008 Lyon, France
| | - Didier Hober
- Laboratoire de Virologie ULR3610 Univ Lille, CHU Lille, 59000 Lille, France; (A.D.); (A.B.); (F.S.); (J.V.)
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Pisano MP, Grandi N, Tramontano E. High-Throughput Sequencing is a Crucial Tool to Investigate the Contribution of Human Endogenous Retroviruses (HERVs) to Human Biology and Development. Viruses 2020; 12:E633. [PMID: 32545287 PMCID: PMC7354619 DOI: 10.3390/v12060633] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/07/2020] [Accepted: 06/10/2020] [Indexed: 01/19/2023] Open
Abstract
Human Endogenous retroviruses (HERVs) are remnants of ancient retroviral infections that represent a large fraction of our genome. Their transcriptional activity is finely regulated in early developmental stages and their expression is modulated in different cell types and tissues. Such activity has an impact on human physiology and pathology that is only partially understood up to date. Novel high-throughput sequencing tools have recently allowed for a great advancement in elucidating the various HERV expression patterns in different tissues as well as the mechanisms controlling their transcription, and overall, have helped in gaining better insights in an all-inclusive understanding of the impact of HERVs in biology of the host.
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Affiliation(s)
- Maria Paola Pisano
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Cagliari, Italy; (M.P.P.); (N.G.)
| | - Nicole Grandi
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Cagliari, Italy; (M.P.P.); (N.G.)
| | - Enzo Tramontano
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, 09042 Cagliari, Italy; (M.P.P.); (N.G.)
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, 09042 Cagliari, Italy
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24
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Reply to Iñiguez et al.: ERVmap is a validated approach to mapping proviral endogenous retroviruses in the human genome. Proc Natl Acad Sci U S A 2019; 116:21352-21353. [PMID: 31594852 DOI: 10.1073/pnas.1908504116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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25
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Tam OH, Ostrow LW, Gale Hammell M. Diseases of the nERVous system: retrotransposon activity in neurodegenerative disease. Mob DNA 2019; 10:32. [PMID: 31372185 PMCID: PMC6659213 DOI: 10.1186/s13100-019-0176-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/18/2019] [Indexed: 12/13/2022] Open
Abstract
Transposable Elements (TEs) are mobile genetic elements whose sequences constitute nearly half of the human genome. Each TE copy can be present in hundreds to thousands of locations within the genome, complicating the genetic and genomic studies of these highly repetitive sequences. The recent development of better tools for evaluating TE derived sequences in genomic studies has enabled an increasing appreciation for the contribution of TEs to human development and disease. While some TEs have contributed novel and beneficial host functions, this review will summarize the evidence for detrimental TE activity in neurodegenerative disorders. Much of the evidence for pathogenicity implicates endogenous retroviruses (ERVs), a subset of TEs that entered the genome by retroviral infections of germline cells in our evolutionary ancestors and have since been passed down as a substantial fraction of the human genome. Human specific ERVs (HERVs) represent some of the youngest ERVs in the genome, and thus are presumed to retain greater function and resultant pathogenic potential.
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Affiliation(s)
- Oliver H Tam
- 1Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 USA
| | - Lyle W Ostrow
- 2Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Molly Gale Hammell
- 1Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 USA
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26
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Investigation of somatic single nucleotide variations in human endogenous retrovirus elements and their potential association with cancer. PLoS One 2019; 14:e0213770. [PMID: 30934003 PMCID: PMC6443178 DOI: 10.1371/journal.pone.0213770] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 02/28/2019] [Indexed: 11/19/2022] Open
Abstract
Human endogenous retroviruses (HERVs) have been investigated for potential links with human cancer. However, the distribution of somatic nucleotide variations in HERV elements has not been explored in detail. This study aims to identify HERV elements with an over-representation of somatic mutations (hot spots) in cancer patients. Four HERV elements with mutation hotspots were identified that overlap with exons of four human protein coding genes. These hotspots were identified based on the significant over-representation (p<8.62e-4) of non-synonymous single-nucleotide variations (nsSNVs). These genes are TNN (HERV-9/LTR12), OR4K15 (HERV-IP10F/LTR10F), ZNF99 (HERV-W/HERV17/LTR17), and KIR2DL1 (MST/MaLR). In an effort to identify mutations that effect survival, all nsSNVs were further evaluated and it was found that kidney cancer patients with mutation C2270G in ZNF99 have a significantly lower survival rate (hazard ratio = 2.6) compared to those without it. Among HERV elements in the human non-protein coding regions, we found 788 HERVs with significantly elevated numbers of somatic single-nucleotide variations (SNVs) (p<1.60e-5). From this category the top three HERV elements with significantly over-represented SNVs are HERV-H/LTR7, HERV-9/LTR12 and HERV-L/MLT2. Majority of the SNVs in these 788 HERV elements are located in three DNA functional groups: long non-coding RNAs (lncRNAs) (60%), introns (22.2%) and transcriptional factor binding sites (TFBS) (14.8%). This study provides a list of mutational hotspots in HERVs, which could potentially be used as biomarkers and therapeutic targets.
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Treger RS, Pope SD, Kong Y, Tokuyama M, Taura M, Iwasaki A. The Lupus Susceptibility Locus Sgp3 Encodes the Suppressor of Endogenous Retrovirus Expression SNERV. Immunity 2019; 50:334-347.e9. [PMID: 30709743 DOI: 10.1016/j.immuni.2018.12.022] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/18/2018] [Accepted: 12/17/2018] [Indexed: 12/24/2022]
Abstract
Elevated endogenous retrovirus (ERV) transcription and anti-ERV antibody reactivity are implicated in lupus pathogenesis. Overproduction of non-ecotropic ERV (NEERV) envelope glycoprotein gp70 and resultant nephritis occur in lupus-prone mice, but whether NEERV mis-expression contributes to lupus etiology is unclear. Here we identified suppressor of NEERV (Snerv) 1 and 2, Krüppel-associated box zinc-finger proteins (KRAB-ZFPs) that repressed NEERV by binding the NEERV long terminal repeat to recruit the transcriptional regulator KAP1. Germline Snerv1/Snerv2 deletion increased activating chromatin modifications, transcription, and gp70 expression from NEERV loci. F1 crosses of lupus-prone New Zealand Black (NZB) and 129 mice to Snerv1/Snerv2-/- mice failed to restore NEERV repression, demonstrating that loss of SNERV underlies the lupus autoantigen gp70 overproduction that promotes nephritis in susceptible mice and that SNERV encodes for Sgp3 (in NZB mice) and Gv-1 loci (in 129 mice). Increased ERV expression in lupus patients inversely correlated with three putative ERV-suppressing KRAB-ZFPs, suggesting that loss of KRAB-ZFP-mediated ERV control may contribute to human lupus pathogenesis.
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Affiliation(s)
- Rebecca S Treger
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Scott D Pope
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Yong Kong
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Molecular Biophysics and Biochemistry, W.M. Keck Foundation Biotechnology Resource Laboratory, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Maria Tokuyama
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Manabu Taura
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Akiko Iwasaki
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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Zhang M, Liang JQ, Zheng S. Expressional activation and functional roles of human endogenous retroviruses in cancers. Rev Med Virol 2019; 29:e2025. [PMID: 30614117 PMCID: PMC6590502 DOI: 10.1002/rmv.2025] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 10/26/2018] [Accepted: 11/05/2018] [Indexed: 12/26/2022]
Abstract
Human endogenous retroviruses (HERVs) are widely believed to be remnants of ancestral germ line infections by exogenous retroviruses. Although HERVs are deemed as “nonfunctional DNAs” due to loss of most of their viral protein coding capacity during evolution as part of the human genome, cumulative evidences are showing the expressional activation and potential roles of HERVs in diseases especially cancers. Work by other researchers and us has observed the dysregulation of HERVs in cancers, identified new HERV‐related genes, and revealed their potential importance in cancer development. Here, we summarized the current knowledge on the mechanisms of the expressional activation and functional roles of HERVs, with a focus on the H family HERV (HERV‐H), in carcinogenesis. HERV expression is regulated by external chemical or physical substances and exogenous virus infection, as well as host factors such as epigenetic DNA methylation, transcription factors, cytokines, and small RNAs. Diverse roles of HERVs have been proposed by acting in the forms of noncoding RNAs, proteins, and transcriptional regulators during carcinogenesis. However, much remains to be learnt about the contributions of HERVs to human cancers. More investigation is warranted to elucidate the functions of these “fossil remnants” yet important viral DNAs in the human genome.
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Affiliation(s)
- Mengwen Zhang
- The Department of Plastic and Reconstructive Surgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Cancer Institute, Second Affiliated Hospital, and Ministry of Education Key Laboratory of Cancer Prevention and Intervention, Zhejiang University School of Medicine, Hangzhou, China
| | - Jessie Qiaoyi Liang
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Shu Zheng
- Cancer Institute, Second Affiliated Hospital, and Ministry of Education Key Laboratory of Cancer Prevention and Intervention, Zhejiang University School of Medicine, Hangzhou, China.,The Department of surgical oncology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
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29
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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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Abstract
Endogenous retrovirus (ERV) sequences make up a large fraction of our genome, yet little is understood about their function and biological relevance. Deep-sequencing data contain valuable information on a genome-wide scale. Yet, due to their highly repetitive nature, analysis of ERVs has been computationally challenging. We describe a bioinformatics tool called ERVmap to analyze transcription of unique sets of human ERVs in a range of cell types in health and disease settings. Our open-source code and accompanied web tool should facilitate researchers in all fields to study the expression patterns of ERVs in sequencing data and should lead to significant advancement in understanding the biological relevance of ERVs in health and disease. Endogenous retroviruses (ERVs) are integrated retroviral elements that make up 8% of the human genome. However, the impact of ERVs on human health and disease is not well understood. While select ERVs have been implicated in diseases, including autoimmune disease and cancer, the lack of tools to analyze genome-wide, locus-specific expression of proviral autonomous ERVs has hampered the progress in the field. Here we describe a method called ERVmap, consisting of an annotated database of 3,220 human proviral ERVs and a pipeline that allows for locus-specific genome-wide identification of proviral ERVs that are transcribed based on RNA-sequencing data, and provide examples of the utility of this tool. Using ERVmap, we revealed cell-type–specific ERV expression patterns in commonly used cell lines as well as in primary cells. We identified 124 unique ERV loci that are significantly elevated in the peripheral blood mononuclear cells of patients with systemic lupus erythematosus that represent an IFN-independent signature. Finally, we identified additional tumor-associated ERVs that correlate with cytolytic activity represented by granzyme and perforin expression in breast cancer tissue samples. The open-source code of ERVmap and the accompanied web tool are made publicly available to quantify proviral ERVs in RNA-sequencing data with ease. Use of ERVmap across a range of diseases and experimental conditions has the potential to uncover novel disease-associated antigens and effectors involved in human health that is currently missed by focusing on protein-coding sequences.
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Wallace AD, Wendt GA, Barcellos LF, de Smith AJ, Walsh KM, Metayer C, Costello JF, Wiemels JL, Francis SS. To ERV Is Human: A Phenotype-Wide Scan Linking Polymorphic Human Endogenous Retrovirus-K Insertions to Complex Phenotypes. Front Genet 2018; 9:298. [PMID: 30154825 PMCID: PMC6102640 DOI: 10.3389/fgene.2018.00298] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/16/2018] [Indexed: 12/13/2022] Open
Abstract
Approximately 8% of the human genome is comprised of endogenous retroviral insertions (ERVs) originating from historic retroviral integration into germ cells. The function of ERVs as regulators of gene expression is well established. Less well studied are insertional polymorphisms of ERVs and their contribution to the heritability of complex phenotypes. The most recent integration of ERV, HERV-K, is expressed in a range of complex human conditions from cancer to neurologic diseases. Using an in-house computational pipeline and whole-genome sequencing data from the diverse 1,000 Genomes Phase 3 population (n = 2,504), we identified 46 polymorphic HERV-K insertions that are tagged by adjacent single nucleotide polymorphisms (SNPs). To test the potential role of polymorphic HERV-K in the heritability of complex diseases, existing databases were queried for enrichment of established relationships between the HERV-K insertion-associated SNPs (hiSNPs), and tissue specific gene expression and disease phenotypes. Overall, hiSNPs for the 46 polymorphic HERV-K sites were statistically enriched (p < 1.0E-16) for eQTLs across 44 human tissues. Fifteen of the 46 HERV-K insertions had hiSNPs annotated in the EMBL-EBI GWAS Catalog and cumulatively associated with >100 phenotypes. Experimental factor ontology enrichment analysis suggests that polymorphic HERV-K specifically contribute to neurologic and immunologic disease phenotypes, including traits related to intra cranial volume (FDR 2.00E-09), Parkinson's disease (FDR 1.80E-09), and autoimmune diseases (FDR 1.80E-09). These results provide strong candidates for context-specific study of polymorphic HERV-K insertions in disease-related traits, serving as a roadmap for future studies of the heritability of complex disease.
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Affiliation(s)
- Amelia D Wallace
- Division of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - George A Wendt
- Division of Epidemiology, School of Community Health Sciences, University of Nevada, Reno, NV, United States
| | - Lisa F Barcellos
- Division of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - Adam J de Smith
- Department of Epidemiology and Biostatistics, Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States
| | - Kyle M Walsh
- Department of Neurosurgery, Duke University, Durham, NC, United States
| | - Catherine Metayer
- Division of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - Joseph F Costello
- Department of Neurosurgery, Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States
| | - Joseph L Wiemels
- Department of Epidemiology and Biostatistics, Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States.,Department of Neurosurgery, Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States
| | - Stephen S Francis
- Division of Epidemiology, School of Community Health Sciences, University of Nevada, Reno, NV, United States.,Department of Epidemiology and Biostatistics, Helen Diller Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States
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Mayer J, Harz C, Sanchez L, Pereira GC, Maldener E, Heras SR, Ostrow LW, Ravits J, Batra R, Meese E, García-Pérez JL, Goodier JL. Transcriptional profiling of HERV-K(HML-2) in amyotrophic lateral sclerosis and potential implications for expression of HML-2 proteins. Mol Neurodegener 2018; 13:39. [PMID: 30068350 PMCID: PMC6091006 DOI: 10.1186/s13024-018-0275-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 07/23/2018] [Indexed: 12/12/2022] Open
Abstract
Background Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder. About 90% of ALS cases are without a known genetic cause. The human endogenous retrovirus multi-copy HERV-K(HML-2) group was recently reported to potentially contribute to neurodegeneration and disease pathogenesis in ALS because of transcriptional upregulation and toxic effects of HML-2 Envelope (Env) protein. Env and other proteins are encoded by some transcriptionally active HML-2 loci. However, more detailed information is required regarding which HML-2 loci are transcribed in ALS, which of their proteins are expressed, and differences between the disease and non-disease states. Methods For brain and spinal cord tissue samples from ALS patients and controls, we identified transcribed HML-2 loci by generating and mapping HML-2-specific cDNA sequences. We predicted expression of HML-2 env gene-derived proteins based on the observed cDNA sequences. Furthermore, we determined overall HML-2 transcript levels by RT-qPCR and investigated presence of HML-2 Env protein in ALS and control tissue samples by Western blotting. Results We identified 24 different transcribed HML-2 loci. Some of those loci are transcribed at relatively high levels. However, significant differences in HML-2 loci transcriptional activities were not seen when comparing ALS and controls. Likewise, overall HML-2 transcript levels, as determined by RT-qPCR, were not significantly different between ALS and controls. Indeed, we were unable to detect full-length HML-2 Env protein in ALS and control tissue samples despite reasonable sensitivity. Rather our analyses suggest that a number of HML-2 protein variants other than full-length Env may potentially be expressed in ALS patients. Conclusions Our results expand and refine recent publications on HERV-K(HML-2) and ALS. Some of our results are in conflict with recent findings and call for further specific analyses. Our profiling of HML-2 transcription in ALS opens up the possibility that HML-2 proteins other than canonical full-length Env may have to be considered when studying the role of HML-2 in ALS disease. Electronic supplementary material The online version of this article (10.1186/s13024-018-0275-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jens Mayer
- Department of Human Genetics, University of Saarland, Homburg, Germany.
| | - Christian Harz
- Department of Human Genetics, University of Saarland, Homburg, Germany
| | - Laura Sanchez
- GENYO. Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
| | - Gavin C Pereira
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Esther Maldener
- Department of Human Genetics, University of Saarland, Homburg, Germany
| | - Sara R Heras
- GENYO. Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain.,Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, 18071, Granada, Spain
| | - Lyle W Ostrow
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 28217, USA
| | - John Ravits
- Department of Neurosciences, School of Medicine, UCSD, San Diego, CA, USA
| | - Ranjan Batra
- Department of Neurosciences, School of Medicine, UCSD, San Diego, CA, USA
| | - Eckart Meese
- Department of Human Genetics, University of Saarland, Homburg, Germany
| | - Jose Luis García-Pérez
- GENYO. Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain.,MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine (IGMM), University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - John L Goodier
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Grandi N, Tramontano E. HERV Envelope Proteins: Physiological Role and Pathogenic Potential in Cancer and Autoimmunity. Front Microbiol 2018; 9:462. [PMID: 29593697 PMCID: PMC5861771 DOI: 10.3389/fmicb.2018.00462] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 02/27/2018] [Indexed: 12/29/2022] Open
Abstract
Human endogenous retroviruses (HERVs) are relics of ancient infections accounting for about the 8% of our genome. Despite their persistence in human DNA led to the accumulation of mutations, HERVs are still contributing to the human transcriptome, and a growing number of findings suggests that their expression products may have a role in various diseases. Among HERV products, the envelope proteins (Env) are currently highly investigated for their pathogenic properties, which could likely be participating to several disorders with complex etiology, particularly in the contexts of autoimmunity and cancer. In fact, HERV Env proteins have been shown, on the one side, to trigger both innate and adaptive immunity, prompting inflammatory, cytotoxic and apoptotic reactions; and, on the other side, to prevent the immune response activation, presenting immunosuppressive properties and acting as immune downregulators. In addition, HERV Env proteins have been shown to induce abnormal cell-cell fusion, possibly contributing to tumor development and metastasizing processes. Remarkably, even highly defective HERV env genes and alternative env splicing variants can provide further mechanisms of pathogenesis. A well-known example is the HERV-K(HML2) env gene that, depending on the presence or the absence of a 292-bp deletion, can originate two proteins of different length (Np9 and Rec) proposed to have oncogenic properties. The understanding of their involvement in complex pathological disorders made HERV Env proteins potential targets for therapeutic interventions. Of note, a monoclonal antibody directed against a HERV-W Env is currently under clinical trial as therapeutic approach for multiple sclerosis, representing the first HERV-based treatment. The present review will focus on the current knowledge of the HERV Env expression, summarizing its role in human physiology and its possible pathogenic effects in various cancer and autoimmune disorders. It moreover analyzes HERV Env possible exploitation for the development of innovative therapeutic strategies.
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Affiliation(s)
- Nicole Grandi
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
| | - Enzo Tramontano
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Cagliari, Italy
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Up-to-date knowledge about the association between multiple sclerosis and the reactivation of human endogenous retrovirus infections. J Neurol 2018; 265:1733-1739. [DOI: 10.1007/s00415-018-8783-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 01/30/2018] [Accepted: 02/01/2018] [Indexed: 12/12/2022]
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Mentis AFA, Dardiotis E, Grigoriadis N, Petinaki E, Hadjigeorgiou GM. Viruses and endogenous retroviruses in multiple sclerosis: From correlation to causation. Acta Neurol Scand 2017; 136:606-616. [PMID: 28542724 PMCID: PMC7159535 DOI: 10.1111/ane.12775] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2017] [Indexed: 12/28/2022]
Abstract
Multiple sclerosis is an immune-mediated disease with an environmental component. According to a long-standing but unproven hypothesis dating to initial descriptions of multiple sclerosis (MS) at the end of the 19th century, viruses are either directly or indirectly implicated in MS pathogenesis. Whether viruses in MS are principally causal or simply contributory remains to be proven, but many viruses or viral elements-predominantly Epstein-Barr virus, human endogenous retroviruses (HERVs) and human herpesvirus 6 (HHV-6) but also less common viruses such as Saffold and measles viruses-are associated with MS. Here, we present an up-to-date and comprehensive review of the main candidate viruses implicated in MS pathogenesis and summarize how these viruses might cause or lead to the hallmark demyelinating and inflammatory lesions of MS. We review data from epidemiological, animal and in vitro studies and in doing so offer a transdisciplinary approach to the topic. We argue that it is crucially important not to interpret "absence of evidence" as "evidence of absence" and that future studies need to focus on distinguishing correlative from causative associations. Progress in the MS-virus field is expected to arise from an increasing body of knowledge on the interplay between viruses and HERVs in MS. Such interactions suggest common HERV-mediated pathways downstream of viral infection that cause both neuroinflammation and neurodegeneration. We also comment on the limitations of existing studies and provide future research directions for the field.
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Affiliation(s)
- A.-F. A. Mentis
- Department of Microbiology; University Hospital of Larissa; University of Thessaly; Larissa Greece
- The Johns Hopkins University, AAP; Baltimore MD USA
| | - E. Dardiotis
- Department of Neurology; University Hospital of Larissa; University of Thessaly; Larissa Greece
| | - N. Grigoriadis
- Laboratory of Experimental Neurology and Neuroimmunology; B’ Department of Neurology; AHEPA University Hospital; Aristotle University of Thessaloniki; Thessaloniki Greece
| | - E. Petinaki
- Department of Microbiology; University Hospital of Larissa; University of Thessaly; Larissa Greece
| | - G. M. Hadjigeorgiou
- Department of Neurology; University Hospital of Larissa; University of Thessaly; Larissa Greece
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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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Morandi E, Tarlinton RE, Tanasescu R, Gran B. Human endogenous retroviruses and multiple sclerosis: Causation, association, or after-effect? Mult Scler 2017; 23:1050-1055. [DOI: 10.1177/1352458517704711] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
From the early days of MS discovery, infections have been proposed as a possible cause of the disease. In the last three decades, an association between human endogenous retrovirus expression and MS has been further investigated and confirmed. Nevertheless, the role of such retroviruses in the disease needs clarification. In this review, we introduce MSRV/HERV-W and describe its association with MS. We then summarize the evidence for the involvement of MSRV/HERV-W in the aetiology and progression of MS and its possible role as biomarker and drug target. Biological mechanisms for HERV effects in MS may involve the activation of innate immune pathways by the envelope protein of MSRV (MSRVEnv). In addition to in vitro and experimental studies, further insight on how HERVs may influence immune-mediated pathology in MS may also come from the use of antiretroviral treatments in patients.
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Affiliation(s)
- Elena Morandi
- Clinical Neurology, Division of Clinical Neuroscience, University of Nottingham School of Medicine, Nottingham, UK
| | - Rachael E. Tarlinton
- School of Veterinary Medicine and Science, University of Nottingham, Nottingham, UK
| | - Radu Tanasescu
- Clinical Neurology, Division of Clinical Neuroscience, University of Nottingham School of Medicine, Nottingham, UK/Division of Clinical Neurosciences, Department of Neurology, University of Medicine and Pharmacy Carol Davila, Colentina Hospital, Bucharest, Romania
| | - Bruno Gran
- Clinical Neurology, Division of Clinical Neuroscience, University of Nottingham School of Medicine, Nottingham, UK/Department of Neurology, Nottingham University Hospitals NHS Trust, Nottingham, UK
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Morandi E, Tanasescu R, Tarlinton RE, Constantinescu CS, Zhang W, Tench C, Gran B. The association between human endogenous retroviruses and multiple sclerosis: A systematic review and meta-analysis. PLoS One 2017; 12:e0172415. [PMID: 28207850 PMCID: PMC5313176 DOI: 10.1371/journal.pone.0172415] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 02/03/2017] [Indexed: 11/18/2022] Open
Abstract
Background The interaction between genetic and environmental factors is crucial to multiple sclerosis (MS) pathogenesis. Human Endogenous Retroviruses (HERVs) are endogenous viral elements of the human genome whose expression is associated with MS. Objective To perform a systematic review and meta-analysis and to assess qualitative and quantitative evidence on the expression of HERV families in MS patients. Methods Medline, Embase and the Cochrane Library were searched for published studies on the association of HERVs and MS. Meta-analysis was performed on the HERV-W family. Odds Ratio (OR) and 95% confidence interval (CI) were calculated for association. Results 43 reports were extracted (25 related to HERV-W, 13 to HERV-H, 9 to HERV-K, 5 to HRES-1 and 1 to HER-15 family). The analysis showed an association between expression of all HERV families and MS. For HERV-W, adequate data was available for meta-analysis. Results from meta-analyses of HERV-W were OR = 22.66 (95%CI 6.32 to 81.20) from 4 studies investigating MSRV/HERV-W (MS-associated retrovirus) envelope mRNA in peripheral blood mononuclear cells, OR = 44.11 (95%CI 12.95 to 150.30) from 6 studies of MSRV/HERV-W polymerase mRNA in serum/plasma and OR = 6.00 (95%CI 3.35 to 10.74) from 4 studies of MSRV/HERV-W polymerase mRNA in CSF. Conclusions This systematic review and meta-analysis shows an association between expression of HERVs, and in particular the HERV-W family, and MS.
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Affiliation(s)
- Elena Morandi
- Division of Clinical Neuroscience, University of Nottingham School of Medicine, Nottingham, Nottingham, United Kingdom
| | - Radu Tanasescu
- Division of Clinical Neuroscience, University of Nottingham School of Medicine, Nottingham, Nottingham, United Kingdom
- Division of Clinical Neurosciences, University of Medicine and Pharmacy Carol Davila, Department of Neurology, Colentina Hospital, Bucharest, Romania
| | - Rachael E. Tarlinton
- University of Nottingham School of Veterinary Medicine and Science, Nottingham, United Kingdom
| | - Cris S. Constantinescu
- Division of Clinical Neuroscience, University of Nottingham School of Medicine, Nottingham, Nottingham, United Kingdom
- Department of Neurology, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
| | - Weiya Zhang
- Division of Rheumatology, Orthopaedics and Dermatology, University of Nottingham School of Medicine, Nottingham, United Kingdom
| | - Christopher Tench
- Division of Clinical Neuroscience, University of Nottingham School of Medicine, Nottingham, Nottingham, United Kingdom
| | - Bruno Gran
- Division of Clinical Neuroscience, University of Nottingham School of Medicine, Nottingham, Nottingham, United Kingdom
- Department of Neurology, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
- * E-mail:
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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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Tao C, Simpson S, Taylor BV, van der Mei I. Association between human herpesvirus & human endogenous retrovirus and MS onset & progression. J Neurol Sci 2016; 372:239-249. [PMID: 28017222 DOI: 10.1016/j.jns.2016.11.060] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 11/02/2016] [Accepted: 11/23/2016] [Indexed: 10/20/2022]
Abstract
This review discusses the role of Epstein-Barr virus (EBV), human herpesvirus 6 (HHV6) and human endogenous retroviruses (HERVs) in the onset and progression of multiple sclerosis (MS). Although EBV has been established as one of the causal factors in MS onset, its role in MS progression is still uncertain. Moreover, interactions between EBV and other risk factor on MS development still need more investment. With less consistent evidence than EBV, HHV6 has also been implicated in the pathogenesis of MS; moreover, it showed a closer connection with the disease activity. Recent studies found that HERVs were associated with the development and progression of MS. Some antiviral treatments have shown promise for clinical interventions in the future. Future studies are yet needed to fully clarify the role of these agents in MS onset and disease course and the modes by which they realise these effects.
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Affiliation(s)
- Chunrong Tao
- Menzies Institute for Medical Research, University of Tasmania, Australia
| | - Steve Simpson
- Menzies Institute for Medical Research, University of Tasmania, Australia
| | - Bruce V Taylor
- Menzies Institute for Medical Research, University of Tasmania, Australia
| | - Ingrid van der Mei
- Menzies Institute for Medical Research, University of Tasmania, Australia.
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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: 57] [Impact Index Per Article: 7.1] [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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Abstract
Retrotransposons have generated about 40 % of the human genome. This review examines the strategies the cell has evolved to coexist with these genomic "parasites", focussing on the non-long terminal repeat retrotransposons of humans and mice. Some of the restriction factors for retrotransposition, including the APOBECs, MOV10, RNASEL, SAMHD1, TREX1, and ZAP, also limit replication of retroviruses, including HIV, and are part of the intrinsic immune system of the cell. Many of these proteins act in the cytoplasm to degrade retroelement RNA or inhibit its translation. Some factors act in the nucleus and involve DNA repair enzymes or epigenetic processes of DNA methylation and histone modification. RISC and piRNA pathway proteins protect the germline. Retrotransposon control is relaxed in some cell types, such as neurons in the brain, stem cells, and in certain types of disease and cancer, with implications for human health and disease. This review also considers potential pitfalls in interpreting retrotransposon-related data, as well as issues to consider for future research.
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Affiliation(s)
- John L. Goodier
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA 212051
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43
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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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Machnik G, Skudrzyk E, Bułdak Ł, Łabuzek K, Ruczyński J, Alenowicz M, Rekowski P, Nowak PJ, Okopień B. A Novel, Highly Selective RT-QPCR Method for Quantification of MSRV Using PNA Clamping Syncytin-1 (ERVWE1). Mol Biotechnol 2016; 57:801-13. [PMID: 25976174 PMCID: PMC4540760 DOI: 10.1007/s12033-015-9873-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
HERV-W is a multi-locus family of human endogenous retroviruses (HERVs) that has been found to play an important role in human physiology and pathology. Two particular members of HERV-W family are of special interests: ERVWE1 (coding syncytin-1, which is a glycoprotein essential in the formation of the placenta) and MSRV (multiple sclerosis-associated retrovirus that is thought to play a significant role in human pathology as a result of its increased expression in the brain tissue and blood cells derived from patients with multiple sclerosis (MS)). Both ERVWE1 and MSRV mRNA share high level of similarity and hence a method that allows to exclusively quantify the MSRV expression in clinical samples would be desirable. We developed a quantitative polymerase chain reaction (QPCR) technique for the detection and quantification of the multiple sclerosis-associated retrovirus. The assay utilises fluorescently labelled oligonucleotide probe, which is complementary to the conservative fragment of MSRV env gene and a peptide nucleic acid (PNA) probe, fully complementary to the ERVWE1 sequence fragment that efficiently blocks the polymerase action on ERVWE1 templates. The PNA molecule, if used parallel with hydrolysis probe in QPCR analysis, greatly facilitates the detection efficiency of MSRV even if ERVWE1 is present abundantly in respect to MSRV in the analysed sample. We achieved a wide and measurable range from 1 × 10 e2 to 1 × 10 e8 copies/reaction; the linearity of the technique was maintained even at the low MSRV level of 1 % in respect to ERVWE1. Using our newly developed method we confirmed that the expression of MSRV takes place in normal human astrocytes and in human umbilical vein endothelial cells in vitro. We also found that the stimulation of human monocytes did not influence the specific expression of MSRV but it caused changes in mRNA level of distinct HERV-W templates.
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Affiliation(s)
- Grzegorz Machnik
- Department of Pharmacology, Medical University of Silesia, Medyków 18, 40-752, Katowice, Poland,
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Morandi E, Tarlinton RE, Gran B. Multiple Sclerosis between Genetics and Infections: Human Endogenous Retroviruses in Monocytes and Macrophages. Front Immunol 2015; 6:647. [PMID: 26734011 PMCID: PMC4689809 DOI: 10.3389/fimmu.2015.00647] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 12/11/2015] [Indexed: 01/02/2023] Open
Abstract
The etiology of multiple sclerosis (MS) is still unknown, but there is strong evidence that genetic predisposition associated with environmental factors can trigger the disease. An estimated 30 million years ago, exogenous retroviruses are thought to have integrated themselves into human germ line cells, becoming part of human DNA and being transmitted over generations. Usually such human endogenous retroviruses (HERVs) are silenced or expressed at low levels, but in some pathological conditions, such as MS, their expression is higher than that in the healthy population. Three HERV families have been associated with MS: HERV-H, HERV-K, and HERV-W. The envelope protein of MS-associated retrovirus (MSRV) from the HERV-W family currently has the strongest evidence as a potential trigger for MS. In addition to expression in peripheral immune cells, MSRV is expressed in monocytes and microglia in central nervous system lesions of people with MS and, through the activation of toll-like receptor 4, it has been shown to drive the production of proinflammatory cytokines, reduction of myelin protein expression, and death of oligodendrocyte precursors. In conclusion, the association between HERVs and MS is well documented and a pathological role for MSRV in MS is plausible. Further studies are required to determine whether the presence of these HERVs is a cause or an effect of immune dysregulation in MS.
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Affiliation(s)
- Elena Morandi
- Clinical Neurology Research Group, Division of Clinical Neuroscience, School of Medicine, University of Nottingham , Nottingham , UK
| | - Rachael E Tarlinton
- School of Veterinary Medicine and Science, University of Nottingham , Nottingham , UK
| | - Bruno Gran
- Clinical Neurology Research Group, Division of Clinical Neuroscience, School of Medicine, University of Nottingham , Nottingham , UK
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Application of “Omics” Technologies for Diagnosis and Pathogenesis of Neurological Infections. Curr Neurol Neurosci Rep 2015. [DOI: 10.1007/s11910-015-0580-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Schmitt K, Heyne K, Roemer K, Meese E, Mayer J. HERV-K(HML-2) rec and np9 transcripts not restricted to disease but present in many normal human tissues. Mob DNA 2015; 6:4. [PMID: 25750667 PMCID: PMC4351823 DOI: 10.1186/s13100-015-0035-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/12/2015] [Indexed: 01/03/2023] Open
Abstract
Background Human endogenous retroviruses of the HERV-K(HML-2) group have been associated with the development of tumor diseases. Various HERV-K(HML-2) loci encode retrovirus-like proteins, and expression of such proteins is upregulated in certain tumor types. HERV-K(HML-2)-encoded Rec and Np9 proteins interact with functionally important cellular proteins and may contribute to tumor development. Though, the biological role of HERV-K(HML-2) transcription and encoded proteins in health and disease is less understood. We therefore investigated transcription specifically of HERV-K(HML-2) rec and np9 mRNAs in a panel of normal human tissues. Results We obtained evidence for rec and np9 mRNA being present in all examined 16 normal tissue types. A total of 18 different HERV-K(HML-2) loci were identified as generating rec or np9 mRNA, among them loci not present in the human reference genome and several of the loci harboring open reading frames for Rec or Np9 proteins. Our analysis identified additional alternative splicing events of HERV-K(HML-2) transcripts, some of them encoding variant Rec/Np9 proteins. We also identified a second HERV-K(HML-2) locus formed by L1-mediated retrotransposition that is likewise transcribed in various human tissues. Conclusions HERV-K(HML-2) rec and np9 transcripts from different HERV-K(HML-2) loci appear to be present in various normal human tissues. It is conceivable that Rec and Np9 proteins and variants of those proteins are part of the proteome of normal human tissues and thus various cell types. Transcription of HERV-K(HML-2) may thus also have functional relevance in normal human cell physiology. Electronic supplementary material The online version of this article (doi:10.1186/s13100-015-0035-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Katja Schmitt
- Institute of Human Genetics, Center of Human and Molecular Biology, Medical Faculty, University of Saarland, 66424 Homburg/Saar, Germany ; Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, K703, Elisabeth Kuhn Street, Frankfurt/Main, 65926 Germany
| | - Kristina Heyne
- José Carreras Research Center, Medical Faculty, University of Saarland, 66424 Homburg/Saar, Germany
| | - Klaus Roemer
- José Carreras Research Center, Medical Faculty, University of Saarland, 66424 Homburg/Saar, Germany
| | - Eckart Meese
- Institute of Human Genetics, Center of Human and Molecular Biology, Medical Faculty, University of Saarland, 66424 Homburg/Saar, Germany
| | - Jens Mayer
- Institute of Human Genetics, Center of Human and Molecular Biology, Medical Faculty, University of Saarland, 66424 Homburg/Saar, Germany ; Center of Human and Molecular Biology, University of Saarland, 66424 Homburg/Saar, Germany
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Differential expression of HERV-K (HML-2) proviruses in cells and virions of the teratocarcinoma cell line Tera-1. Viruses 2015; 7:939-68. [PMID: 25746218 PMCID: PMC4379556 DOI: 10.3390/v7030939] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 02/09/2015] [Accepted: 02/19/2015] [Indexed: 01/12/2023] Open
Abstract
Human endogenous retrovirus (HERV-K (HML-2)) proviruses are among the few endogenous retroviral elements in the human genome that retain coding sequence. HML-2 expression has been widely associated with human disease states, including different types of cancers as well as with HIV-1 infection. Understanding of the potential impact of this expression requires that it be annotated at the proviral level. Here, we utilized the high throughput capabilities of next-generation sequencing to profile HML-2 expression at the level of individual proviruses and secreted virions in the teratocarcinoma cell line Tera-1. We identified well-defined expression patterns, with transcripts emanating primarily from two proviruses located on chromosome 22, only one of which was efficiently packaged. Interestingly, there was a preference for transcripts of recently integrated proviruses, over those from other highly expressed but older elements, to be packaged into virions. We also assessed the promoter competence of the 5’ long terminal repeats (LTRs) of expressed proviruses via a luciferase assay following transfection of Tera-1 cells. Consistent with the RNASeq results, we found that the activity of most LTRs corresponded to their transcript levels.
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Manghera M, Ferguson J, Douville R. Endogenous Retrovirus-K and Nervous System Diseases. Curr Neurol Neurosci Rep 2014; 14:488. [DOI: 10.1007/s11910-014-0488-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Downey RF, Sullivan FJ, Wang-Johanning F, Ambs S, Giles FJ, Glynn SA. Human endogenous retrovirus K and cancer: Innocent bystander or tumorigenic accomplice? Int J Cancer 2014; 137:1249-57. [PMID: 24890612 PMCID: PMC6264888 DOI: 10.1002/ijc.29003] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 05/02/2014] [Accepted: 05/09/2014] [Indexed: 12/20/2022]
Abstract
Harbored as relics of ancient germline infections, human endogenous retroviruses (HERVs) now constitute up to 8% of our genome. A proportion of this sequence has been co-opted for molecular and cellular processes, beneficial to human physiology, such as the fusogenic activity of the envelope protein, a vital component of placentogenesis. However, the discovery of high levels of HERV-K mRNA and protein and even virions in a wide array of cancers has revealed that HERV-K may be playing a more sinister role–a role as an etiological agent in cancer itself. Whether the presence of this retroviral material is simply an epiphenomenon, or an actual causative factor, is a hotly debated topic. This review will summarize the current state of knowledge regarding HERV-K and cancer and attempt to outline the potential mechanisms by which HERV-K could be involved in the onset and promotion of carcinogenesis.
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Affiliation(s)
- Ronan F Downey
- Prostate Cancer Institute, National University of Ireland Galway, Galway, Ireland
| | - Francis J Sullivan
- Prostate Cancer Institute, National University of Ireland Galway, Galway, Ireland.,Department of Radiation Oncology, Galway University Hospitals, Galway, Ireland
| | | | - Stefan Ambs
- Laboratory of Human Carcinogenesis, National Cancer Institute, Bethesda, MD
| | - Francis J Giles
- Prostate Cancer Institute, National University of Ireland Galway, Galway, Ireland.,HRB Clinical Research Facilities Galway & Dublin, National University of Ireland Galway and Trinity College Dublin, Galway, Ireland
| | - Sharon A Glynn
- Prostate Cancer Institute, National University of Ireland Galway, Galway, Ireland
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