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Gong X, He W, Jin W, Ma H, Wang G, Li J, Xiao Y, Zhao Y, Chen Q, Guo H, Yang J, Qi Y, Dong W, Fu M, Li X, Liu J, Liu X, Yin A, Zhang Y, Wei Y. Disruption of maternal vascular remodeling by a fetal endoretrovirus-derived gene in preeclampsia. Genome Biol 2024; 25:117. [PMID: 38715110 PMCID: PMC11075363 DOI: 10.1186/s13059-024-03265-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 04/30/2024] [Indexed: 05/12/2024] Open
Abstract
BACKGROUND Preeclampsia, one of the most lethal pregnancy-related diseases, is associated with the disruption of uterine spiral artery remodeling during placentation. However, the early molecular events leading to preeclampsia remain unknown. RESULTS By analyzing placentas from preeclampsia, non-preeclampsia, and twin pregnancies with selective intrauterine growth restriction, we show that the pathogenesis of preeclampsia is attributed to immature trophoblast and maldeveloped endothelial cells. Delayed epigenetic reprogramming during early extraembryonic tissue development leads to generation of excessive immature trophoblast cells. We find reduction of de novo DNA methylation in these trophoblast cells results in selective overexpression of maternally imprinted genes, including the endoretrovirus-derived gene PEG10 (paternally expressed gene 10). PEG10 forms virus-like particles, which are transferred from the trophoblast to the closely proximate endothelial cells. In normal pregnancy, only a low amount of PEG10 is transferred to maternal cells; however, in preeclampsia, excessive PEG10 disrupts maternal vascular development by inhibiting TGF-beta signaling. CONCLUSIONS Our study reveals the intricate epigenetic mechanisms that regulate trans-generational genetic conflict and ultimately ensure proper maternal-fetal interface formation.
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Affiliation(s)
- Xiaoli Gong
- Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
| | - Wei He
- Medical Genetic Center, Guangdong Women and Children Hospital, Guangzhou, China
| | - Wan Jin
- Euler Technology, Beijing, China
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Hongwei Ma
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, China
- Department Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, China
| | - Gang Wang
- Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, China
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, China
- Human Genetic Resources Preservation Center of Hubei Province, Wuhan, China
- Laboratory of Precision Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Jiaxin Li
- Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
| | - Yu Xiao
- Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, China
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, China
- Human Genetic Resources Preservation Center of Hubei Province, Wuhan, China
- Laboratory of Precision Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yangyu Zhao
- Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
| | | | | | - Jiexia Yang
- Medical Genetic Center, Guangdong Women and Children Hospital, Guangzhou, China
| | - Yiming Qi
- Medical Genetic Center, Guangdong Women and Children Hospital, Guangzhou, China
| | - Wei Dong
- Maternity Ward, Haidian Maternal and Child Health Hospital, Beijing, China
| | - Meng Fu
- Department of Obstetrics and Gynecology, Haidian Maternal and Child Health Hospital, Beijing, China
| | - Xiaojuan Li
- Euler Technology, Beijing, China
- Present Address: International Max Planck Research School for Genome Science, and University of Göttingen, Göttingen Center for Molecular Biosciences, Göttingen, Germany
| | | | - Xinghui Liu
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, China.
- Department Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, China.
| | - Aihua Yin
- Medical Genetic Center, Guangdong Women and Children Hospital, Guangzhou, China.
| | - Yi Zhang
- Euler Technology, Beijing, China.
| | - Yuan Wei
- Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China.
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2
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Sakurai T, Kusama K, Imakawa K. Progressive Exaptation of Endogenous Retroviruses in Placental Evolution in Cattle. Biomolecules 2023; 13:1680. [PMID: 38136553 PMCID: PMC10741562 DOI: 10.3390/biom13121680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/17/2023] [Accepted: 11/19/2023] [Indexed: 12/24/2023] Open
Abstract
Viviparity is made possible by the placenta, a structure acquired relatively recently in the evolutionary history of eutherian mammals. Compared to oviparity, it increases the survival rate of the fetus, owing to the eutherian placenta. Questions such as "How was the placenta acquired?" and "Why is there diversity in placental morphology among mammalian species?" remain largely unsolved. Our present understanding of the molecules regulating placental development remains unclear, owing in no small part to the persistent obscurity surrounding the molecular mechanisms underlying placental acquisition. Numerous genes associated with the development of eutherian placental morphology likely evolved to function at the fetal-maternal interface in conjunction with those participating in embryogenesis. Therefore, identifying these genes, how they were acquired, and how they came to be expressed specifically at the fetal-maternal interface will shed light on some crucial molecular mechanisms underlying placental evolution. Exhaustive studies support the hypothesis that endogenous retroviruses (ERVs) could be evolutional driving forces for trophoblast cell fusion and placental structure in mammalian placentas including those of the bovine species. This review focuses on bovine ERVs (BERVs) and their expression and function in the placenta.
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Affiliation(s)
- Toshihiro Sakurai
- School of Pharmaceutical Science, Ohu University, 31-1 Misumido, Koriyama 963-8611, Fukushima, Japan
| | - Kazuya Kusama
- Department of Endocrine Pharmacology, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji 192-0392, Tokyo, Japan;
| | - Kazuhiko Imakawa
- Research Institute of Agriculture, Tokai University, 9-1-1 Toroku, Higashi-Ku, Kumamoto 862-8652, Japan;
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Sugimoto J, Schust DJ, Sugimoto M, Jinno Y, Kudo Y. Controlling Trophoblast Cell Fusion in the Human Placenta-Transcriptional Regulation of Suppressyn, an Endogenous Inhibitor of Syncytin-1. Biomolecules 2023; 13:1627. [PMID: 38002309 PMCID: PMC10668956 DOI: 10.3390/biom13111627] [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: 08/14/2023] [Revised: 10/24/2023] [Accepted: 11/03/2023] [Indexed: 11/26/2023] Open
Abstract
Cell fusion in the placenta is tightly regulated. Suppressyn is a human placental endogenous retroviral protein that inhibits the profusogenic activities of another well-described endogenous retroviral protein, syncytin-1. In this study, we aimed to elucidate the mechanisms underlying suppressyn's placenta-specific expression. We identified the promoter region and a novel enhancer region for the gene encoding suppressyn, ERVH48-1, and examined their regulation via DNA methylation and their responses to changes in the oxygen concentration. Like other endogenous retroviral genes, the ERVH48-1 promoter sequence is found within a characteristic retroviral 5' LTR sequence. The novel enhancer sequence we describe here is downstream of this LTR sequence (designated EIEs: ERV internal enhancer sequence) and governs placental expression. The placenta-specific expression of ERVH48-1 is tightly controlled by DNA methylation and further regulated by oxygen concentration-dependent, hypoxia-induced transcription factors (HIF1α and HIF2α). Our findings highlight the involvement of (1) tissue specificity through DNA methylation, (2) expression specificity through placenta-specific enhancer regions, and (3) the regulation of suppressyn expression in differing oxygen conditions by HIF1α and HIF2α. We suggest that these regulatory mechanisms are central to normal and abnormal placental development, including the development of disorders of pregnancy involving altered oxygenation, such as preeclampsia, pregnancy-induced hypertension, and fetal growth restriction.
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Affiliation(s)
- Jun Sugimoto
- Department of Obstetrics and Gynecology, Graduate School of Medical Sciences, Hiroshima University, Hiroshima 734-8551, Japan (Y.K.)
| | - Danny J. Schust
- Department of Obstetrics and Gynecology, Duke University, Durham, NC 27710, USA
| | - Makiko Sugimoto
- Department of Obstetrics and Gynecology, Graduate School of Medical Sciences, Hiroshima University, Hiroshima 734-8551, Japan (Y.K.)
| | - Yoshihiro Jinno
- Department of Molecular Biology, University of the Ryukyus, Okinawa 903-0215, Japan
| | - Yoshiki Kudo
- Department of Obstetrics and Gynecology, Graduate School of Medical Sciences, Hiroshima University, Hiroshima 734-8551, Japan (Y.K.)
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4
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Gholami Barzoki M, Shatizadeh Malekshahi S, Heydarifard Z, Mahmodi MJ, Soltanghoraee H. The important biological roles of Syncytin-1 of human endogenous retrovirus W (HERV-W) and Syncytin-2 of HERV-FRD in the human placenta development. Mol Biol Rep 2023; 50:7901-7907. [PMID: 37421503 DOI: 10.1007/s11033-023-08658-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 06/30/2023] [Indexed: 07/10/2023]
Abstract
BACKGROUND Human endogenous retroviruses (HERVs) entered the germ line by retroviral infection from a distant ancestor over 30 million years ago and constitute 8% of the human genome. The majorities of HERVs are non-protein coding and lack function because of the accumulation of mutations, insertions, deletions, and/or truncations. However, a small number of HERV genes carried ORFs with beneficial functions for the host. METHODS & RESULTS In this review, we summarize the structural and important biological roles of two HERV gene products termed Syncytin-1 and Syncytin-2 in human placenta development. Indeed, two retroviral gene products that have important roles in mammalian development, Syncytin-1 (HERV-W) and Syncytin-2 (HERV-FRD), are prime examples encoded by env genes and expressed in the placental trophoblasts. Several pivotal studies revealed that Syncytins are fundamental genes implicated in regulating trophoblast fusion and placenta morphogenesis. CONCLUSION Interestingly, it has been suggested that syncytins may also be implicated in non-fusogenic activities leading to apoptosis, proliferation, and immunosuppressive activities.
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Affiliation(s)
- Mehdi Gholami Barzoki
- Department of Virology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | | | - Zahra Heydarifard
- Hepatitis Research Center, School of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran
| | - Mohamad Javad Mahmodi
- Department of Virology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Haleh Soltanghoraee
- Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
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Skandorff I, Gille J, Ragonnaud E, Andersson AM, Schrödel S, Thirion C, Wagner R, Holst PJ. The Insertion of an Evolutionary Lost Four-Amino-Acid Cytoplasmic Tail Peptide into a Syncytin-1 Vaccine Increases T- and B-Cell Responses in Mice. Viruses 2023; 15:1686. [PMID: 37632028 PMCID: PMC10458386 DOI: 10.3390/v15081686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/30/2023] [Accepted: 07/31/2023] [Indexed: 08/27/2023] Open
Abstract
Human endogenous retrovirus type W (HERV-W) is expressed in various cancers. We previously developed an adenovirus-vectored cancer vaccine targeting HERV-W by encoding an assembled HERV-W group-specific antigen sequence and the HERV-W envelope sequence Syncytin-1. Syncytin-1 is constitutively fusogenic and forms large multinucleated cell fusions when overexpressed. Consequently, immunising humans with a vaccine encoding Syncytin-1 can lead to the formation of extensive syncytia, which is undesirable and poses a potential safety issue. Here, we show experiments in cell lines that restoring an evolutionary lost cleavage site of the fusion inhibitory R-peptide of Syncytin-1 inhibit cell fusion. Interestingly, this modification of the HERV-W vaccine's fusogenicity increased the expression of the vaccine antigens in vitro. It also enhanced Syncytin-1-specific antibody responses and CD8+-mediated T-cell responses compared to the wildtype vaccine in vaccinated mice, with a notable enhancement in responses to subdominant T-cell epitopes but equal responses to dominant epitopes and similar rates of survival following a tumour challenge. The impairment of cell-cell fusion and the enhanced immunogenicity profile of this HERV-W vaccine strengthens the prospects of obtaining a meaningful immune response against HERV-W in patients with HERV-W-overexpressing cancers.
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Affiliation(s)
- Isabella Skandorff
- Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark;
- InProTher, COBIS, Ole Maaloesvej 3, 2200 Copenhagen, Denmark; (E.R.); (A.-M.A.)
| | - Jasmin Gille
- Institute of Medical Microbiology and Hygiene, Molecular Microbiology, University of Regensburg Germany, 93053 Regensburg, Germany; (J.G.); (R.W.)
| | - Emeline Ragonnaud
- InProTher, COBIS, Ole Maaloesvej 3, 2200 Copenhagen, Denmark; (E.R.); (A.-M.A.)
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | | | - Silke Schrödel
- Sirion Biotech GmbH, Am Haag 6, 82166 Graefelfing, Germany; (S.S.); (C.T.)
| | - Christian Thirion
- Sirion Biotech GmbH, Am Haag 6, 82166 Graefelfing, Germany; (S.S.); (C.T.)
| | - Ralf Wagner
- Institute of Medical Microbiology and Hygiene, Molecular Microbiology, University of Regensburg Germany, 93053 Regensburg, Germany; (J.G.); (R.W.)
| | - Peter Johannes Holst
- InProTher, COBIS, Ole Maaloesvej 3, 2200 Copenhagen, Denmark; (E.R.); (A.-M.A.)
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
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6
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Sainty R, Silver MJ, Prentice AM, Monk D. The influence of early environment and micronutrient availability on developmental epigenetic programming: lessons from the placenta. Front Cell Dev Biol 2023; 11:1212199. [PMID: 37484911 PMCID: PMC10358779 DOI: 10.3389/fcell.2023.1212199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 06/27/2023] [Indexed: 07/25/2023] Open
Abstract
DNA methylation is the most commonly studied epigenetic mark in humans, as it is well recognised as a stable, heritable mark that can affect genome function and influence gene expression. Somatic DNA methylation patterns that can persist throughout life are established shortly after fertilisation when the majority of epigenetic marks, including DNA methylation, are erased from the pre-implantation embryo. Therefore, the period around conception is potentially critical for influencing DNA methylation, including methylation at imprinted alleles and metastable epialleles (MEs), loci where methylation varies between individuals but is correlated across tissues. Exposures before and during conception can affect pregnancy outcomes and health throughout life. Retrospective studies of the survivors of famines, such as those exposed to the Dutch Hunger Winter of 1944-45, have linked exposures around conception to later disease outcomes, some of which correlate with DNA methylation changes at certain genes. Animal models have shown more directly that DNA methylation can be affected by dietary supplements that act as cofactors in one-carbon metabolism, and in humans, methylation at birth has been associated with peri-conceptional micronutrient supplementation. However, directly showing a role of micronutrients in shaping the epigenome has proven difficult. Recently, the placenta, a tissue with a unique hypomethylated methylome, has been shown to possess great inter-individual variability, which we highlight as a promising target tissue for studying MEs and mixed environmental exposures. The placenta has a critical role shaping the health of the fetus. Placenta-associated pregnancy complications, such as preeclampsia and intrauterine growth restriction, are all associated with aberrant patterns of DNA methylation and expression which are only now being linked to disease risk later in life.
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Affiliation(s)
- Rebecca Sainty
- Biomedical Research Centre, School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Matt J. Silver
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Andrew M. Prentice
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - David Monk
- Biomedical Research Centre, School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
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7
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Wang Q, Shi Y, Bian Q, Zhang N, Wang M, Wang J, Li X, Lai L, Zhao Z, Yu H. Molecular mechanisms of syncytin-1 in tumors and placental development related diseases. Discov Oncol 2023; 14:104. [PMID: 37326913 DOI: 10.1007/s12672-023-00702-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 05/25/2023] [Indexed: 06/17/2023] Open
Abstract
Human endogenous retroviruses (HERVs) have evolved from exogenous retroviruses and account for approximately 8% of the human genome. A growing number of findings suggest that the abnormal expression of HERV genes is associated with schizophrenia, multiple sclerosis, endometriosis, breast cancer, bladder cancer and other diseases. HERV-W env (syncytin-1) is a membrane glycoprotein which plays an important role in placental development. It includes embryo implantation, fusion of syncytiotrophoblasts and of fertilized eggs, and immune response. The abnormal expression of syncytin-1 is related to placental development-related diseases such as preeclampsia, infertility, and intrauterine growth restriction, as well as tumors such as neuroblastoma, endometrial cancer, and endometriosis. This review mainly focused on the molecular interactions of syncytin-1 in placental development-related diseases and tumors, to explore whether syncytin-1 can be an emerging biological marker and potential therapeutic target.
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Affiliation(s)
- Qianqian Wang
- Department of Biochemistry, Jining Medical University, 133 Hehua Road, Jining, 272067, Shandong, People's Republic of China
| | - Ying Shi
- Department of Biochemistry, Jining Medical University, 133 Hehua Road, Jining, 272067, Shandong, People's Republic of China
| | - Qiang Bian
- Collaborative Innovation Center, Jining Medical University, Jining, 272067, Shandong, People's Republic of China
- Department of Pathophysiology, Weifang Medical University, Weifang, 261053, Shandong, People's Republic of China
| | - Naibin Zhang
- Department of Biochemistry, Jining Medical University, 133 Hehua Road, Jining, 272067, Shandong, People's Republic of China
| | - Meng Wang
- Department of Biochemistry, Jining Medical University, 133 Hehua Road, Jining, 272067, Shandong, People's Republic of China
| | - Jianing Wang
- Department of Biochemistry, Jining Medical University, 133 Hehua Road, Jining, 272067, Shandong, People's Republic of China
| | - Xuan Li
- Department of Biochemistry, Jining Medical University, 133 Hehua Road, Jining, 272067, Shandong, People's Republic of China
| | - Luhao Lai
- Collaborative Innovation Center, Jining Medical University, Jining, 272067, Shandong, People's Republic of China
| | - Zhankui Zhao
- The Affiliated Hospital of Jining Medical University, Jining Medical University, 89 Guhuai Road, Jining, 272029, Shandong, People's Republic of China.
| | - Honglian Yu
- Department of Biochemistry, Jining Medical University, 133 Hehua Road, Jining, 272067, Shandong, People's Republic of China.
- Collaborative Innovation Center, Jining Medical University, Jining, 272067, Shandong, People's Republic of China.
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8
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Fu Y, Song Y, Zhang J, Wei LP, Sun XR. Decreased expression and DNA hypermethylation of syncytin-1 in human villus tissues with unexplained recurrent spontaneous abortion. J Reprod Immunol 2023; 155:103784. [PMID: 36508844 DOI: 10.1016/j.jri.2022.103784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 10/27/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022]
Abstract
Recurrent spontaneous abortion (RSA) affects approximately 5 % of women of reproductive age worldwide. The etiology and pathogenesis of approximately 50 % of RSA cases currently remain unclear, which known as unexplained RSA (URSA). Syncytin-1, an envelope protein encoded by HERV-W gene, is essential for human embryonic development. The purpose of this study was to explore the correlation between syncytin-1 expression and URSA occurrence. The villi tissues of URSA patients and patients with voluntary termination of pregnancy for non-medical reasons in early pregnancy (Control group) were collected. Compared with the Control group, syncytin-1 was abnormally low expressed in URSA villus tissues, and the HERV-W gene promoter was hypermethylated. Compared with the control group, the global DNA methylation level and the expression level of DNA methylases in the villus tissues of the URSA group had no significant difference. In addition, compared with the Control group, URSA villus tissue showed obviously abnormal apoptosis. Overexpression of syncytin-1 promoted the proliferation of HTR-8 cells and inhibited their apoptosis; while knockdown of syncytin-1 inhibited cell proliferation and promoted cell apoptosis. URSA villus tissue exhibited hypermethylation of the HERV-W gene and down-regulation of syncytin-1 expression. Syncytin-1 has the potential to be a predictive and diagnostic biomarker for URSA.
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Affiliation(s)
- Yang Fu
- Department of Reproductive Medicine Center, Jinan Maternity and Child Care Hospital, Jinan 250001, Shandong, China.
| | - Yan Song
- Department of Obstetrics and Gynecology, Jinan Maternity and Child Care Hospital, Jinan 250001, Shandong, China
| | - Juan Zhang
- Department of Obstetrics and Gynecology, Jinan Maternity and Child Care Hospital, Jinan 250001, Shandong, China
| | - Lin-Ping Wei
- Department of Obstetrics and Gynecology, Jinan Maternity and Child Care Hospital, Jinan 250001, Shandong, China
| | - Xiao-Rong Sun
- Department of Pathology, Jinan Maternity and Child Care Hospital, Jinan 250001, Shandong, China
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9
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Zhou H, Zhao C, Wang P, Yang W, Zhu H, Zhang S. Regulators involved in trophoblast syncytialization in the placenta of intrauterine growth restriction. Front Endocrinol (Lausanne) 2023; 14:1107182. [PMID: 36798658 PMCID: PMC9927020 DOI: 10.3389/fendo.2023.1107182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/20/2023] [Indexed: 02/04/2023] Open
Abstract
Placental dysfunction refers to the insufficiency of placental perfusion and chronic hypoxia during early pregnancy, which impairs placental function and causes inadequate supply of oxygen and nutrients to the fetus, affecting fetal development and health. Fetal intrauterine growth restriction, one of the most common outcomes of pregnancy-induced hypertensions, can be caused by placental dysfunction, resulting from deficient trophoblast syncytialization, inadequate trophoblast invasion and impaired vascular remodeling. During placental development, cytotrophoblasts fuse to form a multinucleated syncytia barrier, which supplies oxygen and nutrients to meet the metabolic demands for fetal growth. A reduction in the cell fusion index and the number of nuclei in the syncytiotrophoblast are found in the placentas of pregnancies complicated by IUGR, suggesting that the occurrence of IUGR may be related to inadequate trophoblast syncytialization. During the multiple processes of trophoblasts syncytialization, specific proteins and several signaling pathways are involved in coordinating these events and regulating placental function. In addition, epigenetic modifications, cell metabolism, senescence, and autophagy are also involved. Study findings have indicated several abnormally expressed syncytialization-related proteins and signaling pathways in the placentas of pregnancies complicated by IUGR, suggesting that these elements may play a crucial role in the occurrence of IUGR. In this review, we discuss the regulators of trophoblast syncytialization and their abnormal expression in the placentas of pregnancies complicated by IUGR.
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Affiliation(s)
- Hanjing Zhou
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Hangzhou, China
| | - Chenqiong Zhao
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Hangzhou, China
| | - Peixin Wang
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Hangzhou, China
| | - Weijie Yang
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Hangzhou, China
| | - Haiyan Zhu
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Hangzhou, China
- *Correspondence: Songying Zhang, ; Haiyan Zhu,
| | - Songying Zhang
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Hangzhou, China
- *Correspondence: Songying Zhang, ; Haiyan Zhu,
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Samara A, Khalil A, Brien PO, Herlenius E. The effect of the Delta SARS-CoV-2 variant in maternal infection and pregnancy. iScience 2022; 25:104295. [PMID: 35492217 PMCID: PMC9040522 DOI: 10.1016/j.isci.2022.104295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A greater proportion of pregnant women with COVID-19 have mild disease compared with their non-pregnant counterparts. Paradoxically, however, they are at higher risk of developing severe disease, requiring respiratory support and admission to intensive care. The delta SARS-Cov-2 variant is associated with increased risk of hospitalization and morbidity in unvaccinated pregnant populations. However, it is not known whether the worse pregnancy outcomes associated with the delta variant are due to a direct effect of the virus on the pregnancy, or whether this effect is mediated through more severe maternal infection. Here, we synthesize studies of COVID-19 pregnancies, focusing on the different routes of SARS-CoV-2 infection of lung and placenta, and the mechanisms of syncytial formation for each SARS-CoV-2 variant. To delineate COVID-19 complications in pregnant women, future studies should explore whether the delta variant causes greater placental infection compared to other variants and contributes to increased syncytial formation.
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Affiliation(s)
- Athina Samara
- Division of Clinical Paediatrics, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.,Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Asma Khalil
- The Royal College of Obstetricians and Gynaecologists, London, UK.,University College London Hospitals NHS Foundation Trust, London, UK.,Fetal Medicine Unit, St George's Hospital, St George's University of London, London, UK
| | - Patrick O' Brien
- Vascular Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK.,Fetal Medicine Unit, Liverpool Women's Hospital, University of Liverpool, Liverpool, UK
| | - Eric Herlenius
- Division of Clinical Paediatrics, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.,Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
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11
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Exosomal mediated signal transduction through artificial microRNA (amiRNA): A potential target for inhibition of SARS-CoV-2. Cell Signal 2022; 95:110334. [PMID: 35461900 PMCID: PMC9022400 DOI: 10.1016/j.cellsig.2022.110334] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/13/2022] [Accepted: 04/14/2022] [Indexed: 12/27/2022]
Abstract
Exosome trans-membrane signals provide cellular communication between the cells through transport and/or receiving the signal by molecule, change the functional metabolism, and stimulate and/or inhibit receptor signal complexes. COVID19 genetic transformations are varied in different geographic positions, and single nucleotide polymorphic lineages were reported in the second waves due to the fast mutational rate and adaptation. Several vaccines were developed and in treatment practice, but effective control has yet to reach in cent presence. It was initially a narrow immune-modulating protein target. Controlling these diverse viral strains may inhibit their transuding mechanisms primarily to target RNA genes responsible for COVID19 transcription. Exosomal miRNAs are the main sources of transmembrane signals, and trans-located miRNAs can directly target COVID19 mRNA transcription. This review discussed targeted viral transcription by delivering the artificial miRNA (amiRNA) mediated exosomes in the infected cells and significant resources of exosome and their efficacy.
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12
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Shimode S, Yamamoto T. Characterization of DNA methylation and promoter activity of long terminal repeat elements of feline endogenous retrovirus RDRS C2a. Virus Genes 2021; 58:70-74. [PMID: 34787790 DOI: 10.1007/s11262-021-01878-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/29/2021] [Indexed: 11/25/2022]
Abstract
Endogenous retroviruses (ERVs) are genomic elements derived from retroviral infections in ancestral germ lines. Most ERVs are inactivated by genetic or epigenetic mechanisms, such as DNA methylation. RD-114-virus-related sequence (RDRS) C2a is a feline endogenous retrovirus present in all domestic cats; however, its expression and function are not clearly known. DNA methylation at CpG dinucleotides is a hallmark of silenced ERVs. This study aimed to investigate whether long terminal repeats (LTRs) of RDRS C2a function as a gene regulatory region. The DNA methylation status of RDRS C2a was examined by bisulfite sequencing, and CpG sites in 5' LTR of RDRS C2a were found hypomethylated, whereas those in 3' LTR were hypermethylated in feline cells. Several transcription factor-binding sites were identified in LTRs of RDRS C2a. Luciferase assay suggested that 5' LTR of RDRS C2a exhibited strong transcriptional activity, which was suppressed by in vitro DNA methylation. The study indicates that 5' LTR of RDRS C2a possibly functions as a promoter for itself or neighboring genes.
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Affiliation(s)
- Sayumi Shimode
- Genome Editing Innovation Center, Hiroshima University, 3-10-23 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-0046, Japan.
| | - Takashi Yamamoto
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8528, Japan
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13
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Štafl K, Trávníček M, Kučerová D, Pecnová Ľ, Krchlíková V, Gáliková E, Stepanets V, Hejnar J, Trejbalová K. Heterologous avian system for quantitative analysis of Syncytin-1 interaction with ASCT2 receptor. Retrovirology 2021; 18:15. [PMID: 34158079 PMCID: PMC8220723 DOI: 10.1186/s12977-021-00558-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/05/2021] [Indexed: 12/29/2022] Open
Abstract
Background Human Syncytin-1 is a placentally-expressed cell surface glycoprotein of retroviral origin. After interaction with ASCT2, its cellular receptor, Syncytin-1 triggers cell–cell fusion and formation of a multinuclear syncytiotrophoblast layer of the placenta. The ASCT2 receptor is a multi-spanning membrane protein containing a protruding extracellular part called region C, which has been suggested to be a retrovirus docking site. Precise identification of the interaction site between ASCT2 and Syncytin-1 is challenging due to the complex structure of ASCT2 protein and the background of endogenous ASCT2 gene in the mammalian genome. Chicken cells lack the endogenous background and, therefore, can be used to set up a system with surrogate expression of the ASCT2 receptor. Results We have established a retroviral heterologous chicken system for rapid and reliable assessment of ectopic human ASCT2 protein expression. Our dual-fluorescence system proved successful for large-scale screening of mutant ASCT2 proteins. Using this system, we demonstrated that progressive deletion of region C substantially decreased the amount of ASCT2 protein. In addition, we implemented quantitative assays to determine the interaction of ASCT2 with Syncytin-1 at multiple levels, which included binding of the soluble form of Syncytin-1 to ASCT2 on the cell surface and a luciferase-based assay to evaluate cell–cell fusions that were triggered by Syncytin-1. Finally, we restored the envelope function of Syncytin-1 in a replication-competent retrovirus and assessed the infection of chicken cells expressing human ASCT2 by chimeric Syncytin-1-enveloped virus. The results of the quantitative assays showed that deletion of the protruding region C did not abolish the interaction of ASCT2 with Syncytin-1. Conclusions We present here a heterologous chicken system for effective assessment of the expression of transmembrane ASCT2 protein and its interaction with Syncytin-1. The system profits from the absence of endogenous ASCT2 background and implements the quantitative assays to determine the ASCT2-Syncytin-1 interaction at several levels. Using this system, we demonstrated that the protruding region C was essential for ASCT2 protein expression, but surprisingly, not for the interaction with Syncytin-1 glycoprotein. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s12977-021-00558-0.
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Affiliation(s)
- Kryštof Štafl
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic.,Faculty of Science, Charles University, Albertov 6, 12800, Prague 2, Czech Republic
| | - Martin Trávníček
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic
| | - Dana Kučerová
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic
| | - Ľubomíra Pecnová
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic
| | - Veronika Krchlíková
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic
| | - Eliška Gáliková
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic
| | - Volodymyr Stepanets
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic
| | - Jiří Hejnar
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic.
| | - Kateřina Trejbalová
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic.
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14
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Kristensen MK, Christensen T. Regulation of the expression of human endogenous retroviruses: elements in fetal development and a possible role in the development of cancer and neurological diseases. APMIS 2021; 129:241-253. [PMID: 33683784 DOI: 10.1111/apm.13130] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 03/03/2021] [Indexed: 12/14/2022]
Abstract
Human endogenous retroviruses (HERVs) are remnants of ancient retroviral germline infections. Most HERV sequences are silenced in somatic cells, but interest is emerging on the involvement of HERV derived transcripts and proteins in human physiology and disease. A HERV-W encoded protein, syncytin-1, has been co-opted into fetal physiology, where it plays a role in trophoblast formation. Altered HERV transcription and expression of HERV derived proteins are associated with various cancer types and neurological diseases such as multiple sclerosis (MS). The implication of HERVs as potential mediators of both health and disease suggests important roles of regulatory mechanisms and alterations of these in physiological and pathological processes. The regulation of HERV sequences is mediated by a wide variety of mechanisms, and the focus of this review is on selected aspects of these, including epigenetic mechanisms such as CpG methylation and histone modifications of the HP1-H3K9me axis, viral transactivation events, and regulatory perspectives of transient stimuli in the microenvironment. Increasing knowledge of the regulation of HERV sequences will not only contribute to the understanding of complex pathogeneses, but also may pinpoint potential targets for better diagnosis and treatment in complex diseases as MS.
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15
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Saksena N, Bonam SR, Miranda-Saksena M. Epigenetic Lens to Visualize the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) Infection in COVID-19 Pandemic. Front Genet 2021; 12:581726. [PMID: 33828579 PMCID: PMC8019793 DOI: 10.3389/fgene.2021.581726] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 02/15/2021] [Indexed: 12/14/2022] Open
Abstract
In <20 years, we have witnessed three different epidemics with coronaviruses, SARS-CoV, MERS-CoV, and SARS-CoV-2 in human populations, causing widespread mortality. SARS-CoV-2, through its rapid global spread, has led to the pandemic that we call COVID-19. As of February 1, 2021, the global infections linked to SARS-CoV-2 stand at 103,503,340, with 2,236,960 deaths, and 75,108,099 recoveries. This review attempts to highlight host-pathogen interaction with particular emphasis on the role of epigenetic machinery in regulating the disease. Although researchers, since the start of the pandemic, have been intensely engaged in diverse areas to understand the mechanisms involved in SARS-CoV-2 infection to find answers that can bring about innovative ways to swiftly treat and prevent disease progression, this review provides an overview on how the host epigenetics is modulated and subverted by SARS-CoV-2 to enter the host cells and drive immunopathogenesis. Epigenetics is the study that combines genetic and non-genetic factors controlling phenotypic variation, which are primarily a consequence of external and environmental stimuli. These stimuli alter the activity of a gene without impinging on the DNA code. In viral-host interactions, DNA/RNA methylation, non-coding RNAs, chromatin remodeling, and histone modifications are known to regulate and modulate host gene expression patterns. Viruses such as Coronaviruses (an RNA virus) show intrinsic association with these processes. They have evolved the ability to tamper with host epigenetic machinery to interfere with immune sensing pathways to evade host immune response, thereby enhancing its replication and pathogenesis post-entry. These epigenetic alterations allow the virus to weaken the host's immune response to successfully spread infection. How this occurs, and what epigenetic mechanisms are altered is poorly understood both for coronaviruses and other respiratory RNA viruses. The review highlights several cutting-edge aspects of epigenetic work primarily pertinent to SARS-CoV-2, which has been published between 2019 and 2020 to showcase the current knowledge both in terms of success and failures and take lessons that will assist us in understanding the disease to develop better treatments suited to kill SARS-CoV-2.
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Affiliation(s)
- Nitin Saksena
- EPIGENES Australia Pty Ltd, Melbourne, VIC, Australia
- Institute of Health and Sport, Victoria University, Footscray, VIC, Australia
| | - Srinivasa Reddy Bonam
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, Equipe- Immuno-pathologie et Immuno-intervention Thérapeutique, Sorbonne Université, Université de Paris, Paris, France
| | - Monica Miranda-Saksena
- Herpes Neuropathogenesis Research Group, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia
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16
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Fu Y, Zhuang X, Xia X, Li X, Xiao K, Liu X. Correlation Between Promoter Hypomethylation and Increased Expression of Syncytin-1 in Non-Small Cell Lung Cancer. Int J Gen Med 2021; 14:957-965. [PMID: 33776474 PMCID: PMC7989540 DOI: 10.2147/ijgm.s294392] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 02/19/2021] [Indexed: 12/15/2022] Open
Abstract
Introduction Syncytin-1 is a human endogenous retroviral (HERVW) envelope protein, which has been implicated in trophoblast and cancer cell fusions as well as in immunomodulatory functions. We investigated syncytin-1 expression and promoter methylation in non-small cell lung cancer (NSCLC) and the adjacent, para-carcinoma tissues. In addition, the correlation to patient survival differentiation of between 5-year survival and death group was analyzed. Methods Survival ratio was calculated by Kaplan-Meier survival curve. Death risk assessment was executed by Cox risk regression model. The 5ʹ-LTR methylation level of HERVW promoter was detected by EpiTYPER method. Results Syncytin-1 expression in NSCLC tissue was found to be significantly higher than in para-carcinoma tissues. Moreover, the 5-year survival group has a lower syncytin-1 expression than the death group. Clinical stage and the percentage of syncytin-1 positive cells were top risk factors according to Cox ratio risk regression model analysis. While the methylation level of the 5ʹ-LTR in HERVW gene promoter was relatively lower in NSCLC than para-carcinoma tissues, the methylation status of a CpG-2 site overlapping the Oct-1 binding site was found to be an important element potentially involved in the epigenetic regulation of HERVW gene expression. Conclusion These findings suggest that syncytin-1 could be a biomarker for the diagnosis/prognosis of NSCLC, and further studies are required to elucidate the exact role of syncytin-1 in the development of NSCLC as well as the underlying molecular mechanism for syncytin-1 function and regulation.
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Affiliation(s)
- Yang Fu
- Department of Reproductive Medicine Center, Jinan Maternity and Child Care Hospital, Jinan, 250001, People's Republic of China
| | - Xuewei Zhuang
- Department of Clinical Laboratory Medicine, Shandong Provincial Third Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250031, People's Republic of China.,Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, People's Republic of China
| | - Xiyan Xia
- Department of Microbial Immune, Jinan Vocational College of Nursing, Jinan, 250012, People's Republic of China
| | - Xiaohui Li
- Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, People's Republic of China
| | - Ke Xiao
- Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, People's Republic of China
| | - Xiaojing Liu
- Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, People's Republic of China
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17
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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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18
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Lee AC, Chakladar J, Li WT, Chen C, Chang EY, Wang-Rodriguez J, Ongkeko WM. Tobacco, but Not Nicotine and Flavor-Less Electronic Cigarettes, Induces ACE2 and Immune Dysregulation. Int J Mol Sci 2020; 21:ijms21155513. [PMID: 32752138 PMCID: PMC7432384 DOI: 10.3390/ijms21155513] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 02/07/2023] Open
Abstract
The COVID-19 pandemic caused by the SARS-CoV-2 virus, overlaps with the ongoing epidemics of cigarette smoking and electronic cigarette (e-cig) vaping. However, there is scarce data relating COVID-19 risks and outcome with cigarette or e-cig use. In this study, we mined three independent RNA expression datasets from smokers and vapers to understand the potential relationship between vaping/smoking and the dysregulation of key genes and pathways related to COVID-19. We found that smoking, but not vaping, upregulates ACE2, the cellular receptor that SARS-CoV-2 requires for infection. Both smoking and use of nicotine and flavor-containing e-cigs led to upregulation of pro-inflammatory cytokines and inflammasome-related genes. Specifically, chemokines including CCL20 and CXCL8 are upregulated in smokers, and CCL5 and CCR1 are upregulated in flavor/nicotine-containing e-cig users. We also found genes implicated in inflammasomes, such as CXCL1, CXCL2, NOD2, and ASC, to be upregulated in smokers and these e-cig users. Vaping flavor and nicotine-less e-cigs, however, did not lead to significant cytokine dysregulation and inflammasome activation. Release of inflammasome products, such as IL-1B, and cytokine storms are hallmarks of COVID-19 infection, especially in severe cases. Therefore, our findings demonstrated that smoking or vaping may critically exacerbate COVID-19-related inflammation or increase susceptibility to COVID-19.
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Affiliation(s)
- Abby C. Lee
- Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of California San Diego, La Jolla, CA 92093, USA; (A.C.L.); (J.C.); (W.T.L.); (C.C.)
- Research Service, VA San Diego Healthcare System San Diego, La Jolla, CA 92161, USA
| | - Jaideep Chakladar
- Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of California San Diego, La Jolla, CA 92093, USA; (A.C.L.); (J.C.); (W.T.L.); (C.C.)
- Research Service, VA San Diego Healthcare System San Diego, La Jolla, CA 92161, USA
| | - Wei Tse Li
- Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of California San Diego, La Jolla, CA 92093, USA; (A.C.L.); (J.C.); (W.T.L.); (C.C.)
- Research Service, VA San Diego Healthcare System San Diego, La Jolla, CA 92161, USA
| | - Chengyu Chen
- Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of California San Diego, La Jolla, CA 92093, USA; (A.C.L.); (J.C.); (W.T.L.); (C.C.)
- Research Service, VA San Diego Healthcare System San Diego, La Jolla, CA 92161, USA
| | - Eric Y. Chang
- Department of Radiology, Radiology Service, VA San Diego Healthcare System San Diego, University of California San Diego, La Jolla, CA 92093, USA;
| | - Jessica Wang-Rodriguez
- Department of Pathology, Pathology Service, VA San Diego Healthcare System San Diego, University of California San Diego, La Jolla, CA 92093, USA;
| | - Weg M. Ongkeko
- Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of California San Diego, La Jolla, CA 92093, USA; (A.C.L.); (J.C.); (W.T.L.); (C.C.)
- Research Service, VA San Diego Healthcare System San Diego, La Jolla, CA 92161, USA
- Correspondence: ; Tel.: +1-858-552-8585 (ext. 7165)
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19
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Pruimboom L. Methylation Pathways and SARS-CoV-2 Lung Infiltration and Cell Membrane-Virus Fusion Are Both Subject to Epigenetics. Front Cell Infect Microbiol 2020; 10:290. [PMID: 32574283 PMCID: PMC7265211 DOI: 10.3389/fcimb.2020.00290] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 05/18/2020] [Indexed: 12/15/2022] Open
Abstract
The recent pandemic SARS-CoV-2 outbreak affects all kinds of individuals worldwide. The health, social, and economic impacts of the pandemic are dramatic, and vaccines or specific treatment options are not yet available. The only approaches that we currently have available to stop the epidemic are those of classical epidemic control, such as case isolation, contact tracing and quarantine, physical distancing, and hygiene measures. It is therefore essential to find further preventive measures and possible interventions that can slow down the number of infected individuals and decrease the severity of disease when affected by SARS-CoV-2. It seems that epigenetic mechanisms are an important part of the pathophysiology and illness severity of COVID-19. These mechanisms have been identified in SARS-CoV-2 but also in other viral infections. If and when these mechanisms are confirmed, then epigenetic interventions influencing DNA methylation could be indicated as primary and/or secondary preventive options.
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Affiliation(s)
- Leo Pruimboom
- Facultad de Enfermería y Fisioterapia Salus Infirmorum, Pontifice University of Salamanca, Madrid, Spain.,PNI Europe, The Hague, Netherlands
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Hejnar J, Ruml T. The Current View of Retroviruses as Seen from the Shoulders of a Giant. Viruses 2019; 11:v11090828. [PMID: 31491994 PMCID: PMC6784152 DOI: 10.3390/v11090828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 09/03/2019] [Indexed: 11/16/2022] Open
Abstract
It has now been more than two years since we said our last goodbye to Jan Svoboda (14 [...].
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Affiliation(s)
- Jiří Hejnar
- Department of Viral and Cellular Genetics, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, CZ-14220 Prague, Czech Republic.
| | - Tomáš Ruml
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, CZ-166 28 Prague, Czech Republic.
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21
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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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22
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The Genes of Life and Death: A Potential Role for Placental-Specific Genes in Cancer. Bioessays 2017; 39. [DOI: 10.1002/bies.201700091] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/20/2017] [Indexed: 12/17/2022]
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23
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Hurst TP, Magiorkinis G. Epigenetic Control of Human Endogenous Retrovirus Expression: Focus on Regulation of Long-Terminal Repeats (LTRs). Viruses 2017; 9:v9060130. [PMID: 28561791 PMCID: PMC5490807 DOI: 10.3390/v9060130] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/22/2017] [Accepted: 05/22/2017] [Indexed: 12/25/2022] Open
Abstract
Transposable elements, including endogenous retroviruses (ERVs), comprise almost 45% of the human genome. This could represent a significant pathogenic burden but it is becoming more evident that many of these elements have a positive contribution to make to normal human physiology. In particular, the contributions of human ERVs (HERVs) to gene regulation and the expression of noncoding RNAs has been revealed with the help of new and emerging genomic technologies. HERVs have the common provirus structure of coding open reading frames (ORFs) flanked by two long-terminal repeats (LTRs). However, over the course of evolution and as a consequence of host defence mechanisms, most of the sequences contain INDELs, mutations or have been reduced to single LTRs by recombination. These INDELs and mutations reduce HERV activity. However, there is a trade-off for the host cells in that HERVs can provide beneficial sources of genetic variation but with this benefit comes the risk of pathogenic activity and spread within the genome. For example, the LTRs are of critical importance as they contain promoter sequences and can regulate not only HERV expression but that of human genes. This is true even when the LTRs are located in intergenic regions or are in antisense orientation to the rest of the gene. Uncontrolled, this promoter activity could disrupt normal gene expression or transcript processing (e.g., splicing). Thus, control of HERVs and particularly their LTRs is essential for the cell to manage these elements and this control is achieved at multiple levels, including epigenetic regulations that permit HERV expression in the germline but silence it in most somatic tissues. We will discuss some of the common epigenetic mechanisms and how they affect HERV expression, providing detailed discussions of HERVs in stem cell, placenta and cancer biology.
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Affiliation(s)
- Tara P Hurst
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
| | - Gkikas Magiorkinis
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
- Department of Hygiene, Epidemiology and Medical Statistics, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece.
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Benešová M, Trejbalová K, Kučerová D, Vernerová Z, Hron T, Szabó A, Amouroux R, Klézl P, Hajkova P, Hejnar J. Overexpression of TET dioxygenases in seminomas associates with low levels of DNA methylation and hydroxymethylation. Mol Carcinog 2017; 56:1837-1850. [PMID: 28218476 DOI: 10.1002/mc.22638] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 01/29/2017] [Accepted: 02/16/2017] [Indexed: 12/13/2022]
Abstract
Germ cell tumors and particularly seminomas reflect the epigenomic features of their parental primordial germ cells (PGCs), including genomic DNA hypomethylation and expression of pluripotent cell markers. Because the DNA hypomethylation might be a result of TET dioxygenase activity, we examined expression of TET1-3 enzymes and the level of their product, 5-hydroxymethylcytosine (5hmC), in a panel of histologically characterized seminomas and non-seminomatous germ cell tumors. Expression of TET dioxygenase mRNAs was quantified by real-time PCR. TET1 expression and the level of 5hmC were examined immunohistochemically. Quantitative assessment of 5-methylcytosine (5mC) and 5hmC levels was done by the liquid chromatography-mass spectroscopy technique. We found highly increased expression of TET1 dioxygenase in most seminomas and strong TET1 staining in seminoma cells. Isocitrate dehydrogenase 1 and 2 mutations were not detected, suggesting the enzymatic activity of TET1. The levels of 5mC and 5hmC in seminomas were found decreased in comparison to non-seminomatous germ cell tumors and healthy testicular tissue. We propose that TET1 expression should be studied as a potential marker of seminomas and mixed germ cell tumors and we suggest that elevated expression of TET dioxygenase enzymes is associated with the maintenance of low DNA methylation levels in seminomas. This "anti-methylator" phenotype of seminomas is in contrast to the CpG island methylator phenotype (CIMP) observed in a fraction of tumors of various types.
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Affiliation(s)
- Martina Benešová
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, CZ-14220 Prague 4, Czech Republic
| | - Kateřina Trejbalová
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, CZ-14220 Prague 4, Czech Republic
| | - Dana Kučerová
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, CZ-14220 Prague 4, Czech Republic
| | - Zdenka Vernerová
- Department of Pathology, Third Faculty of Medicine, Charles University in Prague, Ruska 87, CZ-10000, Prague 10, Czech Republic
| | - Tomáš Hron
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, CZ-14220 Prague 4, Czech Republic
| | - Arpád Szabó
- Department of Pathology, Third Faculty of Medicine, Charles University in Prague, Ruska 87, CZ-10000, Prague 10, Czech Republic
| | - Rachel Amouroux
- MRC London Institute of Medical Sciences, London, UK and Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, UK
| | - Petr Klézl
- Department of Urology, Third Faculty of Medicine, Charles University in Prague, Ruska 87, CZ-10000, Prague 10, Czech Republic
| | - Petra Hajkova
- MRC London Institute of Medical Sciences, London, UK and Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, UK
| | - Jiří Hejnar
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, CZ-14220 Prague 4, Czech Republic
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Meyer TJ, Rosenkrantz JL, Carbone L, Chavez SL. Endogenous Retroviruses: With Us and against Us. Front Chem 2017; 5:23. [PMID: 28439515 PMCID: PMC5384584 DOI: 10.3389/fchem.2017.00023] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/20/2017] [Indexed: 12/13/2022] Open
Abstract
Mammalian genomes are scattered with thousands of copies of endogenous retroviruses (ERVs), mobile genetic elements that are relics of ancient retroviral infections. After inserting copies into the germ line of a host, most ERVs accumulate mutations that prevent the normal assembly of infectious viral particles, becoming trapped in host genomes and unable to leave to infect other cells. While most copies of ERVs are inactive, some are transcribed and encode the proteins needed to generate new insertions at novel loci. In some cases, old copies are removed via recombination and other mechanisms. This creates a shifting landscape of ERV copies within host genomes. New insertions can disrupt normal expression of nearby genes via directly inserting into key regulatory elements or by containing regulatory motifs within their sequences. Further, the transcriptional silencing of ERVs via epigenetic modification may result in changes to the epigenetic regulation of adjacent genes. In these ways, ERVs can be potent sources of regulatory disruption as well as genetic innovation. Here, we provide a brief review of the association between ERVs and gene expression, especially as observed in pre-implantation development and placentation. Moreover, we will describe how disruption of the regulated mechanisms of ERVs may impact somatic tissues, mostly in the context of human disease, including cancer, neurodegenerative disorders, and schizophrenia. Lastly, we discuss the recent discovery that some ERVs may have been pressed into the service of their host genomes to aid in the innate immune response to exogenous viral infections.
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Affiliation(s)
- Thomas J Meyer
- Division of Bioinformatics and Computational Biology, Department of Medical Informatics and Clinical Epidemiology, Oregon Health & Science UniversityPortland, OR, USA
| | - Jimi L Rosenkrantz
- Department of Molecular and Medical Genetics, Oregon Health & Science UniversityPortland, OR, USA.,Division of Reproductive & Developmental Sciences, Oregon National Primate Research CenterPortland, OR, USA
| | - Lucia Carbone
- Division of Bioinformatics and Computational Biology, Department of Medical Informatics and Clinical Epidemiology, Oregon Health & Science UniversityPortland, OR, USA.,Department of Molecular and Medical Genetics, Oregon Health & Science UniversityPortland, OR, USA.,Department of Medicine, Knight Cardiovascular Institute, Oregon Health & Science UniversityPortland, OR, USA
| | - Shawn L Chavez
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research CenterPortland, OR, USA.,Departments of Obstetrics and Gynecology and Physiology and Pharmacology, Oregon Health & Science University School of MedicinePortland, OR, USA
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Benešová M, Trejbalová K, Kovářová D, Vernerová Z, Hron T, Kučerová D, Hejnar J. DNA hypomethylation and aberrant expression of the human endogenous retrovirus ERVWE1/syncytin-1 in seminomas. Retrovirology 2017; 14:20. [PMID: 28302141 PMCID: PMC5356313 DOI: 10.1186/s12977-017-0342-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 03/03/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Syncytin-1 and 2, human fusogenic glycoproteins encoded by the env genes of the endogenous retroviral loci ERVWE1 and ERVFRDE1, respectively, contribute to the differentiation of multinucleated syncytiotrophoblast in chorionic villi. In non-trophoblastic cells, however, the expression of syncytins has to be suppressed to avoid potential pathogenic effects. Previously, we have shown that the transcriptional suppression of ERVWE1 promoter is controlled epigenetically by DNA methylation and chromatin modifications. In this study, we describe the aberrant expression of syncytin-1 in biopsies of testicular germ cell tumors. RESULTS We found efficient expression and splicing of syncytin-1 in seminomas and mixed germ cell tumors with seminoma component. Although another fusogenic gene, syncytin-2 was also derepressed in seminomas, its expression was significantly lower than that of syncytin-1. Neither the transcription factor GCM1 nor the increased copy number of ERVWE1 were sufficient for this aberrant expression of syncytin-1 in seminomas. In accordance with our recent finding of the highly increased expression of TET1 dioxygenase in most seminomas, the ERVWE1 promoter was significantly hypomethylated in comparison with the matched controls. In contrast, 5-hydroxymethylcytosine levels were not detectable at the ERVWE1 promoter. We further describe that another endogenous retroviral element adjacent to ERVWE1 remains transcriptionally suppressed and two additional HERV-W family members are only slightly upregulated in seminomas. CONCLUSIONS We conclude that DNA demethylation of the ERVWE1 promoter in seminomas is a prerequisite for syncytin-1 derepression. We propose the spliced syncytin-1 expression as a marker of seminoma and suggest that aberrant expression of endogenous retroviruses might be a correlate of the hypomethylated genome of seminomas.
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Affiliation(s)
- Martina Benešová
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 14220, Prague 4, Czech Republic
| | - Kateřina Trejbalová
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 14220, Prague 4, Czech Republic.
| | - Denisa Kovářová
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 14220, Prague 4, Czech Republic
| | - Zdenka Vernerová
- Department of Pathology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Tomáš Hron
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 14220, Prague 4, Czech Republic
| | - Dana Kučerová
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 14220, Prague 4, Czech Republic
| | - Jiří Hejnar
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 14220, Prague 4, Czech Republic.
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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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Malhotra SS, Banerjee P, Gupta SK. Regulation of trophoblast differentiation during embryo implantation and placentation: Implications in pregnancy complications. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.jrhm.2016.10.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Placental Hypomethylation Is More Pronounced in Genomic Loci Devoid of Retroelements. G3-GENES GENOMES GENETICS 2016; 6:1911-21. [PMID: 27172225 PMCID: PMC4938645 DOI: 10.1534/g3.116.030379] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The human placenta is hypomethylated compared to somatic tissues. However, the degree and specificity of placental hypomethylation across the genome is unclear. We assessed genome-wide methylation of the human placenta and compared it to that of the neutrophil, a representative homogeneous somatic cell. We observed global hypomethylation in placenta (relative reduction of 22%) compared to neutrophils. Placental hypomethylation was pronounced in intergenic regions and gene bodies, while the unmethylated state of the promoter remained conserved in both tissues. For every class of repeat elements, the placenta showed lower methylation but the degree of hypomethylation differed substantially between these classes. However, some retroelements, especially the evolutionarily younger Alu elements, retained high levels of placental methylation. Surprisingly, nonretrotransposon-containing sequences showed a greater degree of placental hypomethylation than retrotransposons in every genomic element (intergenic, introns, and exons) except promoters. The differentially methylated fragments (DMFs) in placenta and neutrophils were enriched in gene-poor and CpG-poor regions. The placentally hypomethylated DMFs were enriched in genomic regions that are usually inactive, whereas hypermethylated DMFs were enriched in active regions. Hypomethylation of the human placenta is not specific to retroelements, indicating that the evolutionary advantages of placental hypomethylation go beyond those provided by expression of retrotransposons and retrogenes.
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30
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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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Stefanetti V, Marenzoni ML, Passamonti F, Cappelli K, Garcia-Etxebarria K, Coletti M, Capomaccio S. High Expression of Endogenous Retroviral Envelope Gene in the Equine Fetal Part of the Placenta. PLoS One 2016; 11:e0155603. [PMID: 27176223 PMCID: PMC4866760 DOI: 10.1371/journal.pone.0155603] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 05/02/2016] [Indexed: 11/19/2022] Open
Abstract
Endogenous retroviruses (ERVs) are proviral phases of exogenous retroviruses that have co-evolved with vertebrate genomes for millions of years. Previous studies have identified the envelope (env) protein genes of retroviral origin preferentially expressed in the placenta which suggests a role in placentation based on their membrane fusogenic capacity and therefore they have been named syncytins. Until now, all the characterized syncytins have been associated with three invasive placentation types: the endotheliochorial (Carnivora), the synepitheliochorial (Ruminantia), and the hemochorial placentation (human, mouse) where they play a role in the syncytiotrophoblast formation. The purpose of the present study was to evaluate whether EqERV env RNA is expressed in horse tissues as well and investigate if the horse, possessing an epitheliochorial placenta, has "captured" a common retroviral env gene with syncytin-like properties in placental tissues. Interestingly, although in the equine placenta there is no syncytiotrophoblast layer at the maternal-fetal interface, our results showed that EqERV env RNA is highly expressed at that level, as expected for a candidate syncytin-like gene but with reduced abundance in the other somatic tissues (nearly 30-fold lower) thus suggesting a possible role in the placental tissue. Although the horse is one of the few domestic animals with a sequenced genome, few studies have been conducted about the EqERV and their expression in placental tissue has never been investigated.
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Affiliation(s)
- Valentina Stefanetti
- Department of Veterinary Medicine, University of Perugia, Perugia, Italy
- * E-mail:
| | | | | | - Katia Cappelli
- Department of Veterinary Medicine, University of Perugia, Perugia, Italy
| | - Koldo Garcia-Etxebarria
- Department of Genetics, Physical Anthropology and Animal Physiology, University of Basque Country-UPV/EHU, BioCruces Health Research Institute, Leioa, Spain
| | - Mauro Coletti
- Department of Veterinary Medicine, University of Perugia, Perugia, Italy
| | - Stefano Capomaccio
- Department of Veterinary Medicine, University of Perugia, Perugia, Italy
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Bolze PA, Patrier S, Cheynet V, Oriol G, Massardier J, Hajri T, Guillotte M, Bossus M, Sanlaville D, Golfier F, Mallet F. Expression patterns of ERVWE1/Syncytin-1 and other placentally expressed human endogenous retroviruses along the malignant transformation process of hydatidiform moles. Placenta 2016; 39:116-24. [DOI: 10.1016/j.placenta.2016.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 01/10/2016] [Accepted: 01/12/2016] [Indexed: 12/19/2022]
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33
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Roland CS, Hu J, Ren CE, Chen H, Li J, Varvoutis MS, Leaphart LW, Byck DB, Zhu X, Jiang SW. Morphological changes of placental syncytium and their implications for the pathogenesis of preeclampsia. Cell Mol Life Sci 2016; 73:365-76. [PMID: 26496726 PMCID: PMC4846582 DOI: 10.1007/s00018-015-2069-x] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 09/29/2015] [Accepted: 10/12/2015] [Indexed: 02/05/2023]
Abstract
Preeclampsia is a hypertensive disease that complicates many pregnancies, typically presenting with new-onset or worsening hypertension and proteinuria. It is well recognized that the placental syncytium plays a key role in the pathogenesis of preeclampsia. This review summarizes the findings pertaining to the structural alterations in the syncytium of preeclamptic placentas and analyzes their pathological implications for the development of preeclampsia. Changes in the trophoblastic lineage, including those in the proliferation of cytotrophoblasts, the formation of syncytiotrophoblast through cell fusion, cell apoptosis and syncytial deportation, are discussed in the context of preeclampsia. Extensive correlations are made between functional deficiencies and the alterations on the levels of gross anatomy, tissue histology, cellular events, ultrastructure, molecular pathways, and gene expression. Attention is given to the significance of dynamic changes in the syncytial turnover in preeclamptic placentas. Specifically, experimental evidences for the complex and obligatory role of syncytin-1 in cell fusion, cell-cycle regulation at the G1/S transition, and apoptosis through AIF-mediated pathway, are discussed in detail in the context of syncytium homeostasis. Finally, the recent observations on the aberrant fibrin deposition in the trophoblastic layer and the trophoblast immature phenotype in preeclamptic placentas and their potential pathogenic impact are also reviewed.
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Affiliation(s)
- Cynthia S Roland
- Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA, 31404, USA
| | - Jian Hu
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, 210009, China
| | - Chun-E Ren
- Department of Obstetrics and Gynecology, Center of Reproductive Medicine, Affiliated Hospital of Weifang Medical University, Weifang, Shandong, China
| | - Haibin Chen
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, China
| | - Jinping Li
- Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA, 31404, USA
- Department of Biomedical Science, Mercer University School of Medicine, Savannah, GA, 31404, USA
| | - Megan S Varvoutis
- Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA, 31404, USA
| | - Lynn W Leaphart
- Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA, 31404, USA
| | - David B Byck
- Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA, 31404, USA
| | - Xueqiong Zhu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China.
| | - Shi-Wen Jiang
- Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA, 31404, USA.
- Department of Biomedical Science, Mercer University School of Medicine, Savannah, GA, 31404, USA.
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34
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Chiappinelli KB, Strissel PL, Desrichard A, Li H, Henke C, Akman B, Hein A, Rote NS, Cope LM, Snyder A, Makarov V, Budhu S, Buhu S, Slamon DJ, Wolchok JD, Pardoll DM, Beckmann MW, Zahnow CA, Merghoub T, Mergoub T, Chan TA, Baylin SB, Strick R. Inhibiting DNA Methylation Causes an Interferon Response in Cancer via dsRNA Including Endogenous Retroviruses. Cell 2015; 162:974-86. [PMID: 26317466 PMCID: PMC4556003 DOI: 10.1016/j.cell.2015.07.011] [Citation(s) in RCA: 1140] [Impact Index Per Article: 126.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 05/04/2015] [Accepted: 06/26/2015] [Indexed: 12/18/2022]
Abstract
We show that DNA methyltransferase inhibitors (DNMTis) upregulate immune signaling in cancer through the viral defense pathway. In ovarian cancer (OC), DNMTis trigger cytosolic sensing of double-stranded RNA (dsRNA) causing a type I interferon response and apoptosis. Knocking down dsRNA sensors TLR3 and MAVS reduces this response 2-fold and blocking interferon beta or its receptor abrogates it. Upregulation of hypermethylated endogenous retrovirus (ERV) genes accompanies the response and ERV overexpression activates the response. Basal levels of ERV and viral defense gene expression significantly correlate in primary OC and the latter signature separates primary samples for multiple tumor types from The Cancer Genome Atlas into low versus high expression groups. In melanoma patients treated with an immune checkpoint therapy, high viral defense signature expression in tumors significantly associates with durable clinical response and DNMTi treatment sensitizes to anti-CTLA4 therapy in a pre-clinical melanoma model.
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Affiliation(s)
- Katherine B Chiappinelli
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD 21287, USA
| | - Pamela L Strissel
- Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, University-Clinic Erlangen, 91054 Erlangen, Germany
| | - Alexis Desrichard
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Huili Li
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD 21287, USA
| | - Christine Henke
- Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, University-Clinic Erlangen, 91054 Erlangen, Germany
| | - Benjamin Akman
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD 21287, USA
| | - Alexander Hein
- Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, University-Clinic Erlangen, 91054 Erlangen, Germany
| | - Neal S Rote
- Department of Reproductive Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Leslie M Cope
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD 21287, USA
| | - Alexandra Snyder
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Vladimir Makarov
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | | | - Sadna Buhu
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Dennis J Slamon
- The Jonsson Comprehensive Cancer Center, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - Jedd D Wolchok
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Drew M Pardoll
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD 21287, USA
| | - Matthias W Beckmann
- Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, University-Clinic Erlangen, 91054 Erlangen, Germany
| | - Cynthia A Zahnow
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD 21287, USA
| | | | - Taha Mergoub
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Timothy A Chan
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Stephen B Baylin
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD 21287, USA.
| | - Reiner Strick
- Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, University-Clinic Erlangen, 91054 Erlangen, Germany.
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Toufaily C, Lokossou AG, Vargas A, Rassart É, Barbeau B. A CRE/AP-1-like motif is essential for induced syncytin-2 expression and fusion in human trophoblast-like model. PLoS One 2015; 10:e0121468. [PMID: 25781974 PMCID: PMC4364025 DOI: 10.1371/journal.pone.0121468] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 02/14/2015] [Indexed: 11/18/2022] Open
Abstract
Syncytin-2 is encoded by the envelope gene of Endogenous Retrovirus-FRD (ERVFRD-1) and plays a critical role in fusion of placental trophoblasts leading to the formation of the multinucleated syncytiotrophoblast. Its expression is consequently regulated in a strict manner. In the present study, we have identified a forskolin-responsive region located between positions -300 to -150 in the Syncytin-2 promoter region. This 150 bp region in the context of a minimal promoter mediated an 80-fold induction of promoter activity following forskolin stimulation. EMSA analyses with competition experiments with nuclear extracts from forskolin-stimulated BeWo cells demonstrated that the -211 to -177 region specifically bound two forskolin-induced complexes, one of them containing a CRE/AP-1-like motif. Site-directed mutagenesis of the CRE/AP-1 binding site in the context of the Syncytin-2 promoter or a heterologous promoter showed that this motif was mostly essential for forskolin-induced promoter activity. Transfection experiments with dominant negative mutants and constitutively activated CREB expression vectors in addition to Chromatin Immunoprecipitation suggested that a CREB family member, CREB2 was binding and acting through the CRE/AP-1 motif. We further demonstrated the binding of JunD to this same motif. Similar to forskolin and soluble cAMP, CREB2 and JunD overexpression induced Syncytin-2 promoter activity in a CRE/AP-1-dependent manner and Syncytin-2 expression. In addition, BeWo cell fusion was induced by both CREB2 and JunD overexpression, while being repressed following silencing of either gene. These results thereby demonstrate that induced expression of Syncytin-2 is highly dependent on the interaction of bZIP-containing transcription factors to a CRE/AP-1 motif and that this element is important for the regulation of Syncytin-2 expression, which results in the formation of the peripheral syncytiotrophoblast layer.
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Affiliation(s)
- Chirine Toufaily
- Département des Sciences Biologiques and Centre de recherche BioMed, Université du Québec à Montréal, Montréal, Canada
| | - Adjimon Gatien Lokossou
- Département des Sciences Biologiques and Centre de recherche BioMed, Université du Québec à Montréal, Montréal, Canada
| | - Amandine Vargas
- Département des Sciences Biologiques and Centre de recherche BioMed, Université du Québec à Montréal, Montréal, Canada
| | - Éric Rassart
- Département des Sciences Biologiques and Centre de recherche BioMed, Université du Québec à Montréal, Montréal, Canada
| | - Benoit Barbeau
- Département des Sciences Biologiques and Centre de recherche BioMed, Université du Québec à Montréal, Montréal, Canada
- * E-mail:
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Lu Q, Li J, Senkowski C, Tang Z, Wang J, Huang T, Wang X, Terry K, Brower S, Glasgow W, Chen H, Jiang SW. Promoter Hypermethylation and Decreased Expression of Syncytin-1 in Pancreatic Adenocarcinomas. PLoS One 2015; 10:e0134412. [PMID: 26230721 PMCID: PMC4521816 DOI: 10.1371/journal.pone.0134412] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 07/08/2015] [Indexed: 02/05/2023] Open
Abstract
Syncytin-1 is a member of human endogenous retroviral W gene family (HERVW1). Known to be expressed in human placental trophoblast, syncytin-1 protein mediates the fusion of cytotrophoblasts for the formation of syncytiotrophoblasts, the terminally differentiated form of trophoblast lineage. In addition, in vitro studies indicate that syncytin-1 possessed nonfusogenic functions such as those for immune suppression, cell cycle regulation and anti-apoptotic activities. Overexpression of syncytin-1 has been observed in various malignant tissues including breast, endometrial and ovarian cancers. It was reported that syncytin-1 gene expression is associated with dynamic changes of DNA hypomethylation in the 5' LTR. In this study, applying the real-time PCR, Western blot analysis and immunohistochemistry methods, we demonstrate a constitutive expression of syncytin-1 in normal pancreas tissues as well as normal tissues adjacent to cancer lesions. Moreover, a reduced expression is found in the pancreatic adenocarcinoma tissues. The expression levels of syncytin-1 are not correlated with the stage, historical grade and gender, but inversely correlated with patients' age. Furthermore, COBRA and bisulfite sequencing results indicated that the lower expression of syncytin-1 is correlated with the hypermethylation of two CpG dinucleotides in the 5' LTR of syncytin-1 gene. The nonfusogenic function of syncytin-1 in normal pancreas as well as its role(s) in the pathogenesis and progression of pancreatic cancers remains to be investigated. Identification of the two CpG dinucleotides around transcription start site as key epigenetic elements has provided valuable information for further studies on the epigenetic regulation of syncytin-1 in pancreatic cancer cells.
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Affiliation(s)
- Qinsheng Lu
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, China
- Department of Biomedical Science, Mercer University School of Medicine, Savannah, GA, United States of America
| | - Jinping Li
- Department of Biomedical Science, Mercer University School of Medicine, Savannah, GA, United States of America
- Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA, United States of America
| | - Christopher Senkowski
- Department of Surgery, Curtis and Elizabeth Anderson Cancer Institute, Memorial Health University Medical Center, Savannah, GA, United States of America
| | - Zuoqing Tang
- Department of Medical Genetics, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Jianhao Wang
- School of Pharmaceutical Engineering and Life Science, Changzhou University, Changzhou, Jiangsu Province, China
| | - Tianhe Huang
- Department of Biomedical Science, Mercer University School of Medicine, Savannah, GA, United States of America
| | - Xue Wang
- Department of Biomedical Science, Mercer University School of Medicine, Savannah, GA, United States of America
| | - Karen Terry
- Department of Surgery, Curtis and Elizabeth Anderson Cancer Institute, Memorial Health University Medical Center, Savannah, GA, United States of America
| | - Steven Brower
- Department of Surgery & Surgical Oncology, Beth Israel Medical Center, New York, NY, United States of America
| | - Wayne Glasgow
- Department of Biomedical Science, Mercer University School of Medicine, Savannah, GA, United States of America
| | - Haibin Chen
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, China
- * E-mail: (SWJ); (HC)
| | - Shi-Wen Jiang
- Department of Biomedical Science, Mercer University School of Medicine, Savannah, GA, United States of America
- Department of Obstetrics and Gynecology, the Second Affiliated Hospital of Wenzhou Medical University, Wenzhou 325027, China
- Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA, United States of America
- * E-mail: (SWJ); (HC)
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Lokossou AG, Toudic C, Barbeau B. Implication of human endogenous retrovirus envelope proteins in placental functions. Viruses 2014; 6:4609-27. [PMID: 25421890 PMCID: PMC4246240 DOI: 10.3390/v6114609] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 11/02/2014] [Accepted: 11/07/2014] [Indexed: 12/21/2022] Open
Abstract
Human endogenous retroviruses (ERVs) represent 8% of the total human genome. Although the majority of these ancient proviral sequences have only retained non-coding long terminal repeats (LTRs), a number of “endogenized” retroviral genes encode functional proteins. Previous studies have underlined the implication of these ERV-derived proteins in the development and the function of the placenta. In this review, we summarize recent findings showing that two ERV genes, termed Syncytin-1 and Syncytin-2, which encode former envelope (Env) proteins, trigger fusion events between villous cytotrophoblasts and the peripheral multinucleated syncytiotrophoblast layer. Such fusion events maintain the stability of this latter cell structure, which plays an important role in fetal development by the active secretion of various soluble factors, gas exchange and regulation of fetomaternal immunotolerance. We also highlight new studies showing that these ERV proteins, in addition to their localization at the cell surface of cytotrophoblasts, are also incorporated on the surface of various extracellular microvesicles, including exosomes. Such exosome-associated proteins could be involved in the various functions attributed to these vesicles and could provide a form of tropism. Additionally, through their immunosuppressive domains, these ERV proteins could also contribute to fetomaternal immunotolerance in a local and more distal manner. These various aspects of the implication of Syncytin-1 and -2 in placental function are also addressed in the context of the placenta-related disorder, preeclampsia.
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Affiliation(s)
- Adjimon Gatien Lokossou
- Département des Sciences Biologiques and Centre de recherche BioMed, Université du Québec à Montréal, 2080 Saint-Urbain, Montréal, PQ H2X 3X8, Canada.
| | - Caroline Toudic
- Département des Sciences Biologiques and Centre de recherche BioMed, Université du Québec à Montréal, 2080 Saint-Urbain, Montréal, PQ H2X 3X8, Canada.
| | - Benoit Barbeau
- Département des Sciences Biologiques and Centre de recherche BioMed, Université du Québec à Montréal, 2080 Saint-Urbain, Montréal, PQ H2X 3X8, Canada.
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Ma X, Li J, Brost B, Cheng W, Jiang SW. Decreased expression and DNA methylation levels of GATAD1 in preeclamptic placentas. Cell Signal 2014; 26:959-67. [PMID: 24462704 PMCID: PMC4644424 DOI: 10.1016/j.cellsig.2014.01.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 01/13/2014] [Indexed: 12/13/2022]
Abstract
Expression of syncytin-1, or the human endogenous retroviral family W member 1 (HERVWE1) in human placental trophoblasts is regulated by DNA methylation. Increased DNA methylation and decreased expression of syncytin-1 have been observed in preeclamptic placentas. The syncytin-1-mediated fusogenic as well as non-fusogenic activities, e.g., cell cycle promotion, anti-apoptosis, and immune suppression, are implicated in the pathogenic changes in preeclamptic placentas. It is noteworthy that in a close vicinity to syncytin-1 there are two genes, peroxisome biogenesis factor 1 (PEX1) and GATA zinc finger domain containing 1 (GATAD1), as well as multiple CpG islands around these genes. In this study we determined if these adjacent genes might, like syncytin-1, subject to epigenetic regulation in preeclamptic placentas. Data from quantitative real-time PCR and Western blotting indicated that while PEX1 expression remained stable, GATAD1 expression was significantly decreased in the third-trimester placentas associated with preeclampsia than those associated with normal pregnancy. Immunohistochemistry detected high GATAD1 expression in trophoblast linage, and confirmed its reduced levels in preeclamptic placentas. However, COBRA and bisulfate sequencing detected decreased DNA methylation in levels in the 3 [prime] region of GATAD1 gene in preeclamptic placentas. The positive correlation between 3 [prime] methylation and GATAD1 expression was confirmed by treatment of choriocarcinoma JAR cells with DNMT inhibitor. These data pointed to a potential role of GATAD1 for the syncytium deficiency often associated with preeclamptic placentas. The sharp contrast of the methylation alterations for the closely positioned GATAD1 and HERVWE1 may provide a useful model for studying the accurate control of DNA methylation as well as their positive and negative impact on gene expression in placental trophoblasts.
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Affiliation(s)
- Xiaoling Ma
- Department of Gynecology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China; Department of Biomedical Science, Mercer University School of Medicine, Savannah Campus, GA, USA
| | - Jinping Li
- Department of Biomedical Science, Mercer University School of Medicine, Savannah Campus, GA, USA; Department of Obstetrics and Gynecology, Mayo Clinic and Mayo Medical College, Rochester, MN, USA
| | - Brian Brost
- Department of Obstetrics and Gynecology, Mayo Clinic and Mayo Medical College, Rochester, MN, USA
| | - Wenjun Cheng
- Department of Gynecology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
| | - Shi-Wen Jiang
- Department of Biomedical Science, Mercer University School of Medicine, Savannah Campus, GA, USA; Department of Obstetrics and Gynecology, Mayo Clinic and Mayo Medical College, Rochester, MN, USA; Department of Obstetrics and Gynecology, Memorial Health Hospital, Savannah, GA, USA.
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Huang Q, Chen H, Li J, Oliver M, Ma X, Byck D, Gao Y, Jiang SW. Epigenetic and non-epigenetic regulation of syncytin-1 expression in human placenta and cancer tissues. Cell Signal 2014; 26:648-56. [PMID: 24216608 DOI: 10.1016/j.cellsig.2013.11.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 11/01/2013] [Indexed: 02/05/2023]
Abstract
Syncytin-1 is a human endogenous retroviral envelope gene (HERVW1) product specifically expressed in placental trophoblasts. By mediating the formation of syncytiotrophoblasts through cell-cell fusion, syncytin-1 plays a critical role for the placental barrier, endocrine and exchange functions. During pregnancy, syncytin-1 expression is dynamically regulated by various pathophysiological factors and pathways. This review summarizes and examines published data on epigenetic and non-epigenetic regulation of syncytin-1 gene expression, with a focus on the changes of syncytin-1 DNA methylation and expression in placental trophoblasts under preeclamptic and hypoxic conditions. The functions of syncytiotrophoblasts, the fusogenic and non-fusogenic activities of syncytin-1, and aberrant activation of syncytin-1 expression in cancer cells are also discussed. New findings on the epigenetic regulation of syncytin-1 in placentas from monozygotic/dichorionic discordant twins are analyzed. The close correlation among changes of DNMTs expression, syncytin-1 gene methylation, and syncytin-1 mRNA levels, in placentas associated with discordant fetal growth indicated a dynamic nature of syncytin-1 regulation.
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Affiliation(s)
- Qiang Huang
- The Second Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi 710004, China; Department of Biological Science, Mercer University School of Medicine, Savannah, GA 31404, USA
| | - Haibin Chen
- Department of Department of Histology and Embryology, Shantou University Medical College, Guandong, China
| | - Jinping Li
- Department of Biological Science, Mercer University School of Medicine, Savannah, GA 31404, USA; Department of Obstetrics and Gynecology, Mayo Medical College, Mayo Clinic and Mayo Foundation, 55902, USA
| | - Matthew Oliver
- Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA 31404, USA
| | - Xiaoling Ma
- Department of Biological Science, Mercer University School of Medicine, Savannah, GA 31404, USA
| | - David Byck
- Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA 31404, USA
| | - Ya Gao
- The Second Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi 710004, China.
| | - Shi-Wen Jiang
- Department of Biological Science, Mercer University School of Medicine, Savannah, GA 31404, USA; Department of Obstetrics and Gynecology, Mayo Medical College, Mayo Clinic and Mayo Foundation, 55902, USA; Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA 31404, USA.
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Transcriptional derepression of the ERVWE1 locus following influenza A virus infection. J Virol 2014; 88:4328-37. [PMID: 24478419 DOI: 10.1128/jvi.03628-13] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Syncytin-1, a fusogenic protein encoded by a human endogenous retrovirus of the W family (HERV-W) element (ERVWE1), is expressed in the syncytiotrophoblast layer of the placenta. This locus is transcriptionally repressed in adult tissues through promoter CpG methylation and suppressive histone modifications. Whereas syncytin-1 appears to be crucial for the development and functioning of the human placenta, its ectopic expression has been associated with pathological conditions, such as multiple sclerosis and schizophrenia. We previously reported on the transactivation of HERV-W elements, including ERVWE1, during influenza A/WSN/33 virus infection in a range of human cell lines. Here we report the results of quantitative PCR analyses of transcripts encoding syncytin-1 in both cell lines and primary fibroblast cells. We observed that spliced ERVWE1 transcripts and those encoding the transcription factor glial cells missing 1 (GCM1), acting as an enhancer element upstream of ERVWE1, are prominently upregulated in response to influenza A/WSN/33 virus infection in nonplacental cells. Knockdown of GCM1 by small interfering RNA followed by infection suppressed the transactivation of ERVWE1. While the infection had no influence on CpG methylation in the ERVWE1 promoter, chromatin immunoprecipitation assays detected decreased H3K9 trimethylation (H3K9me3) and histone methyltransferase SETDB1 levels along with influenza virus proteins associated with ERVWE1 and other HERV-W loci in infected CCF-STTG1 cells. The present findings suggest that an exogenous influenza virus infection can transactivate ERVWE1 by increasing transcription of GCM1 and reducing H3K9me3 in this region and in other regions harboring HERV-W elements. IMPORTANCE Syncytin-1, a protein encoded by the env gene in the HERV-W locus ERVWE1, appears to be crucial for the development and functioning of the human placenta and is transcriptionally repressed in nonplacental tissues. Nevertheless, its ectopic expression has been associated with pathological conditions, such as multiple sclerosis and schizophrenia. In the present paper, we report findings suggesting that an exogenous influenza A virus infection can transactivate ERVWE1 by increasing the transcription of GCM1 and reducing the repressive histone mark H3K9me3 in this region and in other regions harboring HERV-W elements. These observations have implications of potential relevance for viral pathogenesis and for conditions associated with the aberrant transcription of HERV-W loci.
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Logan PC, Mitchell MD, Lobie PE. DNA methyltransferases and TETs in the regulation of differentiation and invasiveness of extra-villous trophoblasts. Front Genet 2013; 4:265. [PMID: 24363660 PMCID: PMC3849743 DOI: 10.3389/fgene.2013.00265] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 11/15/2013] [Indexed: 01/21/2023] Open
Abstract
Specialized cell types of trophoblast cells form the placenta in which each cell type has particular properties of proliferation and invasion. The placenta sustains the growth of the fetus throughout pregnancy and any aberrant trophoblast differentiation or invasion potentially affects the future health of the child and adult. Recently, the field of epigenetics has been applied to understand differentiation of trophoblast lineages and embryonic stem cells (ESC), from fertilization of the oocyte onward. Each trophoblast cell-type has a distinctive epigenetic profile and we will concentrate on the epigenetic mechanism of DNA methyltransferases and TETs that regulate DNA methylation. Environmental factors affecting the mother potentially regulate the DNA methyltransferases in trophoblasts, and so do steroid hormones, cell cycle regulators, such as p53, and cytokines, especially interlukin-1β. There are interesting questions of why trophoblast genomes are globally hypomethylated yet specific genes can be suppressed by hypermethylation (in general, tumor suppressor genes, such as E-cadherin) and how invasive cell-types are liable to have condensed chromatin, as in metastatic cancer cells. Future work will attempt to understand the interactive nature of all epigenetic mechanisms together and their effect on the complex biological system of trophoblast differentiation and invasion in normal as well as pathological conditions.
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Affiliation(s)
- Philip C Logan
- The Liggins Institute, The University of Auckland Auckland, New Zealand
| | - Murray D Mitchell
- University of Queensland Centre for Clinical Research, University of Queensland Brisbane, QLD, Australia
| | - Peter E Lobie
- Cancer Science Institute of Singapore, National University of Singapore Singapore, Singapore
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Comprehensive analysis of human endogenous retrovirus group HERV-W locus transcription in multiple sclerosis brain lesions by high-throughput amplicon sequencing. J Virol 2013; 87:13837-52. [PMID: 24109235 DOI: 10.1128/jvi.02388-13] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Human endogenous retroviruses (HERVs) of the HERV-W group comprise hundreds of loci in the human genome. Deregulated HERV-W expression and HERV-W locus ERVWE1-encoded Syncytin-1 protein have been implicated in the pathogenesis of multiple sclerosis (MS). However, the actual transcription of HERV-W loci in the MS context has not been comprehensively analyzed. We investigated transcription of HERV-W in MS brain lesions and white matter brain tissue from healthy controls by employing next-generation amplicon sequencing of HERV-W env-specific reverse transcriptase (RT) PCR products, thus revealing transcribed HERV-W loci and the relative transcript levels of those loci. We identified more than 100 HERV-W loci that were transcribed in the human brain, with a limited number of loci being predominantly transcribed. Importantly, relative transcript levels of HERV-W loci were very similar between MS and healthy brain tissue samples, refuting deregulated transcription of HERV-W env in MS brain lesions, including the high-level-transcribed ERVWE1 locus encoding Syncytin-1. Quantitative RT-PCR likewise did not reveal differences in MS regarding HERV-W env general transcript or ERVWE1- and ERVWE2-specific transcript levels. However, we obtained evidence for interindividual differences in HERV-W transcript levels. Reporter gene assays indicated promoter activity of many HERV-W long terminal repeats (LTRs), including structurally incomplete LTRs. Our comprehensive analysis of HERV-W transcription in the human brain thus provides important information on the biology of HERV-W in MS lesions and normal human brain, implications for study design, and mechanisms by which HERV-W may (or may not) be involved in MS.
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Role of DNA methylation in expression and transmission of porcine endogenous retroviruses. J Virol 2013; 87:12110-20. [PMID: 23986605 DOI: 10.1128/jvi.03262-12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Porcine endogenous retroviruses (PERV) represent a major safety concern in pig-to-human xenotransplantation. To date, no PERV infection of a xenograft recipient has been recorded; however, PERVs are transmissible to human cells in vitro. Some recombinants of the A and C PERV subgroups are particularly efficient in infection and replication in human cells. Transcription of PERVs has been described in most pig cells, but their sequence and insertion polymorphism in the pig genome impede identification of transcriptionally active or silenced proviral copies. Furthermore, little is known about the epigenetic regulation of PERV transcription. Here, we report on the transcriptional suppression of PERV by DNA methylation in vitro and describe heavy methylation in the majority of PERV 5' long terminal repeats (LTR) in porcine tissues. In contrast, we have detected sparsely methylated or nonmethylated proviruses in the porcine PK15 cells, which express human cell-tropic PERVs. We also demonstrate the resistance of PERV DNA methylation to inhibitors of methylation and deacetylation. Finally, we show that the high permissiveness of various human cell lines to PERV infection coincides with the inability to efficiently silence the PERV proviruses by 5'LTR methylation. In conclusion, we suggest that DNA methylation is involved in PERV regulation, and that only a minor fraction of proviruses are responsible for the PERV RNA expression and porcine cell infectivity.
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Kovářová D, Plachý J, Kosla J, Trejbalová K, Čermák V, Hejnar J. Downregulation of HOPX Controls Metastatic Behavior in Sarcoma Cells and Identifies Genes Associated with Metastasis. Mol Cancer Res 2013; 11:1235-47. [DOI: 10.1158/1541-7786.mcr-12-0687] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Strissel PL, Ruebner M, Thiel F, Wachter D, Ekici AB, Wolf F, Thieme F, Ruprecht K, Beckmann MW, Strick R. Reactivation of codogenic endogenous retroviral (ERV) envelope genes in human endometrial carcinoma and prestages: Emergence of new molecular targets. Oncotarget 2013; 3:1204-19. [PMID: 23085571 PMCID: PMC3717959 DOI: 10.18632/oncotarget.679] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Endometrial carcinoma (EnCa) is the most common invasive gynaecologic carcinoma. Over 85% of EnCa are classified as endometrioid, expressing steroid hormone receptors and mostly involving pathological prestages. Human endogenous retroviruses (ERV) are chromosomally integrated genes, account for about 8% of the human genome and are implicated in the etiology of carcinomas. The majority of ERV envelope (env) coding genes are either not present or not consistently represented between common gene expression microarrays. The aim of this study was to analyse the absolute gene expression of all known 21 ERV env genes including 19 codogenic and two env genes with premature stop codons in EnCa, endometrium as well as in hyperplasia and polyps. For EnCa seven env genes had high expression with >200 mol/ng cDNA (e.g. envH1-3, Syncytin-1, envT), two middle >50 mol/ng cDNA (envFc2, erv-3) and 12 low <50 mol/ng cDNA (e.g. Syncytin-2, envV2). Regarding tumor parameters, Syncytin-1 and Syncytin-2 were significantly over-expressed in advanced stage pT2 compared to pT1b. In less differentiated EnCa Syncytin-1, erv-3, envT and envFc2 were significantly over-expressed. Syncytin-1, Syncytin-2 and erv-3 were specific to glandular epithelial cells of polyps, hyperplasia and EnCa using immunohistochemistry. An analysis of 10 patient-matched EnCa with endometrium revealed that the ERV-W 5' long terminal repeat regulating Syncytin-1 was hypomethylated, including the ERE and CRE overlapping MeCP2 sites. Functional analyses showed that 10 env genes were regulated by methylation in EnCa using the RL95-2 cell line. In conclusion, over-expressed env genes could serve as indicators for pathological pre-stages and EnCa.
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Affiliation(s)
- Pamela L Strissel
- University-Clinic Erlangen, Department of Gynecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Germany
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Reduced syncytin-1 expression levels in placental syndromes correlates with epigenetic hypermethylation of the ERVW-1 promoter region. PLoS One 2013; 8:e56145. [PMID: 23457515 PMCID: PMC3573012 DOI: 10.1371/journal.pone.0056145] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 01/07/2013] [Indexed: 01/28/2023] Open
Abstract
Terminal differentiation of villous cytotrophoblasts (CT) ends in formation of the multinucleated syncytiotrophoblast representing the fetal-maternal interface. Aberrations during this cell-fusion process are associated with Intrauterine Growth Restriction (IUGR), Preeclampsia (PE) and High Elevated Liver and Low Platelets (HELLP) Syndrome. Syncytin-1, the envelope gene of the human Endogenous Retrovirus ERVW-1, is one of the most important genes involved in cell-fusion and showed decreased gene expression during these pathological pregnancies. The aim of this study was to determine the methylation pattern of the entire promoter of ERVW-1 and to correlate these findings with the expression profile of Syncytin-1 in the placental syndromes. 14 isolated villous cytotrophoblasts from control (n = 3), IUGR (n = 3), PE (n = 3), PE/IUGR (n = 3) and HELLP/IUGR (n = 2) placentae were used to determine the mean methylation level (ML) for the ERVW-1 promoter region. ML rose significantly from 29% in control CTs to 49% in IUGR, 53% in PE, 47% in PE/IUGR and 64% in HELLP/IUGR indicating an epigenetic down-regulation of Syncytin-1 by promoter hypermethylation. DNA demethylation of the trophoblast like cell lines BeWo, JEG-3 and JAR with 5-AZA-2′desoxycytidine (AZA) showed an increased Syncytin-1 expression and fusion ability in all cell lines. Promoter activity of the 5′LTR could be inhibited by hypermethylation 42-fold using a luciferase based reporter-gene assay. Finally overexpression of the methyltransferases DNMT3a and LSH could be responsible for a decreased Syncytin-1 expression by promoter hypermethylation of ERVW-1. Our study linked decreased Syncytin-1 expression to an epigenetic hypermethylation of the entire promoter of ERVW-1. Based on our findings we are predicting a broad aberrant epigenetic DNA-methylation pattern in pathological placentae affecting placentogenesis, but also the development of the fetus and the mother during pregnancy.
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47
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Laska MJ, Nissen KK, Nexø BA. (Some) cellular mechanisms influencing the transcription of human endogenous retrovirus, HERV-Fc1. PLoS One 2013; 8:e53895. [PMID: 23382858 PMCID: PMC3557288 DOI: 10.1371/journal.pone.0053895] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 12/06/2012] [Indexed: 11/18/2022] Open
Abstract
DNA methylation and histone acetylation are epigenetic modifications that act as regulators of gene expression. DNA methylation is considered an important mechanism for silencing of retroelements in the mammalian genome. However, the methylation of human endogenous retroviruses (HERVs) is not well investigated. The aim of this study was to investigate the transcriptional potential of HERV-Fc1 proviral 5'LTR in more detail, and examined the specific influence of CpG methylation on this LTR in number of cell lines. Specifically, the role of demethylating chemicals e.g. 5-aza-2' deoxycytidine and Trichostatin-A, in inducing or reactivating expression of HERV-Fc1 specific sequences and the mechanisms were investigated. In our present study, 5-aza-dC is shown to be a powerful inducer of HERV-Fc1, and at the same time it strongly inhibits methylation of DNA. Treatment with this demethylating agent 5-aza-dC, results in significantly increased levels of HERV-Fc1 expression in cells previously not expressing HERV-Fc1, or with a very low expression level. The extent of expression of HERV-Fc1 RNAs precisely correlates with the apparent extent of demethylation of the related DNA sequences. In conclusion, the results suggest that inhibition of DNA methylation/histone deacetylase can interfere with gene silencing mechanisms affecting HERV-Fc1 expression in human cells.
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48
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Szafranski P, Dharmadhikari AV, Brosens E, Gurha P, Kolodziejska KE, Zhishuo O, Dittwald P, Majewski T, Mohan KN, Chen B, Person RE, Tibboel D, de Klein A, Pinner J, Chopra M, Malcolm G, Peters G, Arbuckle S, Guiang SF, Hustead VA, Jessurun J, Hirsch R, Witte DP, Maystadt I, Sebire N, Fisher R, Langston C, Sen P, Stankiewicz P. Small noncoding differentially methylated copy-number variants, including lncRNA genes, cause a lethal lung developmental disorder. Genome Res 2012; 23:23-33. [PMID: 23034409 PMCID: PMC3530681 DOI: 10.1101/gr.141887.112] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
An unanticipated and tremendous amount of the noncoding sequence of the human genome is transcribed. Long noncoding RNAs (lncRNAs) constitute a significant fraction of non-protein-coding transcripts; however, their functions remain enigmatic. We demonstrate that deletions of a small noncoding differentially methylated region at 16q24.1, including lncRNA genes, cause a lethal lung developmental disorder, alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV), with parent-of-origin effects. We identify overlapping deletions 250 kb upstream of FOXF1 in nine patients with ACD/MPV that arose de novo specifically on the maternally inherited chromosome and delete lung-specific lncRNA genes. These deletions define a distant cis-regulatory region that harbors, besides lncRNA genes, also a differentially methylated CpG island, binds GLI2 depending on the methylation status of this CpG island, and physically interacts with and up-regulates the FOXF1 promoter. We suggest that lung-transcribed 16q24.1 lncRNAs may contribute to long-range regulation of FOXF1 by GLI2 and other transcription factors. Perturbation of lncRNA-mediated chromatin interactions may, in general, be responsible for position effect phenomena and potentially cause many disorders of human development.
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Affiliation(s)
- Przemyslaw Szafranski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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Šenigl F, Auxt M, Hejnar J. Transcriptional provirus silencing as a crosstalk of de novo DNA methylation and epigenomic features at the integration site. Nucleic Acids Res 2012; 40:5298-312. [PMID: 22379139 PMCID: PMC3384319 DOI: 10.1093/nar/gks197] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 02/12/2012] [Accepted: 02/13/2012] [Indexed: 12/03/2022] Open
Abstract
The autonomous transcription of integrated retroviruses strongly depends on genetic and epigenetic effects of the chromatin at the site of integration. These effects are mostly suppressive and proviral activity can be finally silenced by mechanisms, such as DNA methylation and histone modifications. To address the role of the integration site at the whole-genome-scale, we performed clonal analysis of provirus silencing with an avian leucosis/sarcoma virus-based reporter vector and correlated the transcriptional silencing with the epigenomic landscape of respective integrations. We demonstrate efficient provirus silencing in human HCT116 cell line, which is strongly but not absolutely dependent on the de novo DNA methyltransferase activity, particularly of Dnmt3b. Proviruses integrated close to the transcription start sites of active genes into the regions enriched in H3K4 trimethylation display long-term stability of expression and are resistant to the transcriptional silencing after over-expression of Dnmt3a or Dnmt3b. In contrast, proviruses in the intergenic regions tend to spontaneous transcriptional silencing even in Dnmt3a(-/-) Dnmt3b(-/-) cells. The silencing of proviruses within genes is accompanied with DNA methylation of long terminal repeats, whereas silencing in intergenic regions is DNA methylation-independent. These findings indicate that the epigenomic features of integration sites are crucial for their permissivity to the proviral expression.
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Affiliation(s)
- Filip Šenigl
- Department of Cellular and Viral Genetics, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídeňská 1083, 14220 Prague, Czech Republic
| | | | - Jiří Hejnar
- Department of Cellular and Viral Genetics, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídeňská 1083, 14220 Prague, Czech Republic
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Pérot P, Mugnier N, Montgiraud C, Gimenez J, Jaillard M, Bonnaud B, Mallet F. Microarray-based sketches of the HERV transcriptome landscape. PLoS One 2012; 7:e40194. [PMID: 22761958 PMCID: PMC3386233 DOI: 10.1371/journal.pone.0040194] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 06/02/2012] [Indexed: 12/15/2022] Open
Abstract
Human endogenous retroviruses (HERVs) are spread throughout the genome and their long terminal repeats (LTRs) constitute a wide collection of putative regulatory sequences. Phylogenetic similarities and the profusion of integration sites, two inherent characteristics of transposable elements, make it difficult to study individual locus expression in a large-scale approach, and historically apart from some placental and testis-regulated elements, it was generally accepted that HERVs are silent due to epigenetic control. Herein, we have introduced a generic method aiming to optimally characterize individual loci associated with 25-mer probes by minimizing cross-hybridization risks. We therefore set up a microarray dedicated to a collection of 5,573 HERVs that can reasonably be assigned to a unique genomic position. We obtained a first view of the HERV transcriptome by using a composite panel of 40 normal and 39 tumor samples. The experiment showed that almost one third of the HERV repertoire is indeed transcribed. The HERV transcriptome follows tropism rules, is sensitive to the state of differentiation and, unexpectedly, seems not to correlate with the age of the HERV families. The probeset definition within the U3 and U5 regions was used to assign a function to some LTRs (i.e. promoter or polyA) and revealed that (i) autonomous active LTRs are broadly subjected to operational determinism (ii) the cellular gene density is substantially higher in the surrounding environment of active LTRs compared to silent LTRs and (iii) the configuration of neighboring cellular genes differs between active and silent LTRs, showing an approximately 8 kb zone upstream of promoter LTRs characterized by a drastic reduction in sense cellular genes. These gathered observations are discussed in terms of virus/host adaptive strategies, and together with the methods and tools developed for this purpose, this work paves the way for further HERV transcriptome projects.
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Affiliation(s)
- Philippe Pérot
- Joint Unit Hospices Civils de Lyon, bioMérieux, Cancer Biomarkers Research Group, Centre Hospitalier Lyon Sud, Lyon, France
| | - Nathalie Mugnier
- BioMérieux, Data and Knowledge Laboratory, Marcy l’Etoile, France
| | - Cécile Montgiraud
- Joint Unit Hospices Civils de Lyon, bioMérieux, Cancer Biomarkers Research Group, Centre Hospitalier Lyon Sud, Lyon, France
| | - Juliette Gimenez
- Joint Unit Hospices Civils de Lyon, bioMérieux, Cancer Biomarkers Research Group, Centre Hospitalier Lyon Sud, Lyon, France
| | - Magali Jaillard
- BioMérieux, Data and Knowledge Laboratory, Marcy l’Etoile, France
| | - Bertrand Bonnaud
- BioMérieux, Data and Knowledge Laboratory, Marcy l’Etoile, France
| | - François Mallet
- Joint Unit Hospices Civils de Lyon, bioMérieux, Cancer Biomarkers Research Group, Centre Hospitalier Lyon Sud, Lyon, France
- * E-mail:
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