1
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Okudaira N, Ishizaka Y, Tamamori-Adachi M. Resveratrol blocks retrotransposition of LINE-1 through PPAR α and sirtuin-6. Sci Rep 2022; 12:7772. [PMID: 35546166 PMCID: PMC9095727 DOI: 10.1038/s41598-022-11761-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 04/26/2022] [Indexed: 11/09/2022] Open
Abstract
The retroelement long interspersed element-1 (LINE-1 or L1) comprises about 17% of the human genome. L1 retrotransposition is known to cause genomic instability and related disorders, and resveratrol suppresses this retrotransposition; however, the underlying mechanism is still not elucidated. Recent observations showed that low-molecular-weight compounds might induce L1 retrotransposition through unknown mechanisms. This study aimed to determine polyphenol resveratrol (RV)'s effect on L1-RTP (retrotransposition) in somatic cells. Surprisingly, RV completely blocked L1-RTP. Experiments using the PPARα inhibitor GW6471 or siRNA-mediated PPARα depletion showed that RV-mediated L1-RTP's inhibition depended on peroxisome proliferator-activated receptor α (PPARα). We demonstrated that RV inhibits p38 and cAMP response element binding protein phosphorylation, which are involved in MAPK signaling, and the L1-ORF1 protein's chromatin recruitment. Furthermore, RV increased the expression of sirtuin-6 (SIRT6), which inhibited the activation of L1. The sirtuins family, SIRT1, SIRT6, and SIRT7, but not SIRT3, are involved in RV-mediated inhibition of L1-RTP. Overall, our findings suggest that RV directly modulates PPARα-mediated L1-RTP in somatic cells and that MAPK signaling interacts with SIRT6 closely and may play a role in preventing human diseases such as cancer.
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Affiliation(s)
- Noriyuki Okudaira
- Department of Biochemistry, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo, 173-8605, Japan.
| | - Yukihito Ishizaka
- Department of Intractable Diseases, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan
| | - Mimi Tamamori-Adachi
- Department of Biochemistry, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo, 173-8605, Japan
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2
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Takahashi F, Zhang C, Hohjoh H, Raveney B, Yamamura T, Hayashi N, Oki S. Immune-mediated neurodegenerative trait provoked by multimodal derepression of long-interspersed nuclear element-1. iScience 2022; 25:104278. [PMID: 35573205 PMCID: PMC9097630 DOI: 10.1016/j.isci.2022.104278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 03/25/2022] [Accepted: 04/18/2022] [Indexed: 11/25/2022] Open
Abstract
Neurodegeneration is a process involving both cell autonomous and non-cell autonomous neuron loss, followed by a collapse of neural networks, but its pathogenesis is poorly understood. We have previously demonstrated that Eomes-positive helper T (Eomes + Th) cells recognizing LINE-1(L1)-derived prototypic antigen ORF1 mediate neurotoxicity associated with the neurodegenerative pathology of experimental autoimmune encephalomyelitis (EAE). Here, we show that Eomes + Th cells accumulate in the CNS of mouse models of authentic neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and Alzheimer’s disease (AD), and secrete the neurotoxic granzyme B after encounter with ORF1 antigen. Multimodal derepression of neuronal L1 transcription is observed in EAE and ALS/AD models during neurodegeneration in active and cell cycle-mediated manner, respectively. These data suggest that the adventitious concurrence of immune-mediated neurodegenerative traits by Eomes + Th cells and ectopic expression of L1-derived antigen(s) in the inflamed CNS may materialize a communal and previously unappreciated pathogenesis of neurodegeneration. Eomes + Th cells accumulate in the CNS with undergoing neurodegeneration in common Multimodal L1 derepression is emerged in neuron cells under neurodegeneration Eomes + Th cells recognize L1-ORF1 antigen to exert neurotoxicity via granzyme B Immune-mediated neurotoxicity may embody a novel pathogenesis of neurodegeneration
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Affiliation(s)
- Fumio Takahashi
- Department of Immunology, National Institute of Neuroscience, NCNP, Tokyo, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Chenyang Zhang
- Department of Immunology, National Institute of Neuroscience, NCNP, Tokyo, Japan
| | - Hirohiko Hohjoh
- Department of Molecular Pharmacology, National Institute of Neuroscience, NCNP, Tokyo, Japan
| | - Ben Raveney
- Department of Immunology, National Institute of Neuroscience, NCNP, Tokyo, Japan
| | - Takashi Yamamura
- Department of Immunology, National Institute of Neuroscience, NCNP, Tokyo, Japan
| | - Nobuhiro Hayashi
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Shinji Oki
- Department of Immunology, National Institute of Neuroscience, NCNP, Tokyo, Japan
- Corresponding author
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3
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Lou C, Goodier JL, Qiang R. A potential new mechanism for pregnancy loss: considering the role of LINE-1 retrotransposons in early spontaneous miscarriage. Reprod Biol Endocrinol 2020; 18:6. [PMID: 31964400 PMCID: PMC6971995 DOI: 10.1186/s12958-020-0564-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 01/07/2020] [Indexed: 12/14/2022] Open
Abstract
LINE1 retrotransposons are mobile DNA elements that copy and paste themselves into new sites in the genome. To ensure their evolutionary success, heritable new LINE-1 insertions accumulate in cells that can transmit genetic information to the next generation (i.e., germ cells and embryonic stem cells). It is our hypothesis that LINE1 retrotransposons, insertional mutagens that affect expression of genes, may be causal agents of early miscarriage in humans. The cell has evolved various defenses restricting retrotransposition-caused mutation, but these are occasionally relaxed in certain somatic cell types, including those of the early embryo. We predict that reduced suppression of L1s in germ cells or early-stage embryos may lead to excessive genome mutation by retrotransposon insertion, or to the induction of an inflammatory response or apoptosis due to increased expression of L1-derived nucleic acids and proteins, and so disrupt gene function important for embryogenesis. If correct, a novel threat to normal human development is revealed, and reverse transcriptase therapy could be one future strategy for controlling this cause of embryonic damage in patients with recurrent miscarriages.
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Affiliation(s)
- Chao Lou
- Department of Genetics, Northwest Women’s and Children’s Hospital, 1616 Yanxiang Road, Xi’an, Shaanxi Province People’s Republic of China
| | - John L. Goodier
- 0000 0001 2171 9311grid.21107.35McKusick-Nathans Deartment of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Rong Qiang
- Department of Genetics, Northwest Women’s and Children’s Hospital, 1616 Yanxiang Road, Xi’an, Shaanxi Province People’s Republic of China
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4
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Barbieri D, Elvira-Matelot E, Pelinski Y, Genève L, de Laval B, Yogarajah G, Pecquet C, Constantinescu SN, Porteu F. Thrombopoietin protects hematopoietic stem cells from retrotransposon-mediated damage by promoting an antiviral response. J Exp Med 2018; 215:1463-1480. [PMID: 29615469 PMCID: PMC5940259 DOI: 10.1084/jem.20170997] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 12/28/2017] [Accepted: 03/02/2018] [Indexed: 12/13/2022] Open
Abstract
Propagation of retrotransposons induces genomic instability. Their roles in HSCs remain poorly studied. Barbieri et al. show that retrotransposon expression and mobilization are involved in long-lasting HSC impairment upon irradiation. These effects are counteracted by the self-renewal cytokine THPO through induction of interferon-like response. Maintenance of genomic integrity is crucial for the preservation of hematopoietic stem cell (HSC) potential. Retrotransposons, spreading in the genome through an RNA intermediate, have been associated with loss of self-renewal, aging, and DNA damage. However, their role in HSCs has not been addressed. Here, we show that mouse HSCs express various retroelements (REs), including long interspersed element-1 (L1) recent family members that further increase upon irradiation. Using mice expressing an engineered human L1 retrotransposition reporter cassette and reverse transcription inhibitors, we demonstrate that L1 retransposition occurs in vivo and is involved in irradiation-induced persistent γH2AX foci and HSC loss of function. Thus, RE represents an important intrinsic HSC threat. Furthermore, we show that RE activity is restrained by thrombopoietin, a critical HSC maintenance factor, through its ability to promote a potent interferon-like, antiviral gene response in HSCs. This uncovers a novel mechanism allowing HSCs to minimize irradiation-induced injury and reinforces the links between DNA damage, REs, and antiviral immunity.
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Affiliation(s)
- Daniela Barbieri
- INSERM UMR1170, Villejuif, France.,Université Paris-Saclay, Paris, France.,Gustave Roussy Cancer Campus, Paris, France
| | - Emilie Elvira-Matelot
- INSERM UMR1170, Villejuif, France.,Université Paris-Saclay, Paris, France.,Gustave Roussy Cancer Campus, Paris, France
| | - Yanis Pelinski
- INSERM UMR1170, Villejuif, France.,Université Paris-Saclay, Paris, France.,Gustave Roussy Cancer Campus, Paris, France
| | - Laetitia Genève
- INSERM UMR1170, Villejuif, France.,Université Paris-Saclay, Paris, France.,Gustave Roussy Cancer Campus, Paris, France
| | - Bérengère de Laval
- Centre d'Immunologie Marseille-Luminy, Université Aix-Marseille, Institut National de la Santé et de la Recherche Médicale, U1104, Centre National de la Recherche Scientifique, UMR 7280
| | - Gayathri Yogarajah
- INSERM UMR1170, Villejuif, France.,Université Paris-Saclay, Paris, France.,Gustave Roussy Cancer Campus, Paris, France
| | - Christian Pecquet
- Ludwig Institute for Cancer Research, Brussels, Belgium.,SIGN Pole, de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Stefan N Constantinescu
- Ludwig Institute for Cancer Research, Brussels, Belgium.,SIGN Pole, de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Françoise Porteu
- INSERM UMR1170, Villejuif, France .,Université Paris-Saclay, Paris, France.,Gustave Roussy Cancer Campus, Paris, France
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5
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Habibi L, Pedram M, AmirPhirozy A, Bonyadi K. Mobile DNA Elements: The Seeds of Organic Complexity on Earth. DNA Cell Biol 2015. [DOI: 10.1089/dna.2015.2938] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Laleh Habibi
- Department of Pharmaceutics, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
- Cellular and Molecular Nutrition Department, School of Nutritional Science and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehrdad Pedram
- Department of Genetics and Molecular Medicine, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Akbar AmirPhirozy
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Khadijeh Bonyadi
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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6
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Otsubo T, Okamura T, Hagiwara T, Ishizaka Y, Dohi T, Kawamura YI. Retrotransposition of long interspersed nucleotide element-1 is associated with colitis but not tumors in a murine colitic cancer model. PLoS One 2015; 10:e0116072. [PMID: 25710700 PMCID: PMC4339839 DOI: 10.1371/journal.pone.0116072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/05/2014] [Indexed: 12/22/2022] Open
Abstract
Long interspersed element-1 (L1) is a transposable element that can move within the genome, potentially leading to genome diversity and modified gene function. Although L1 activity in somatic cells is normally suppressed through DNA methylation, some L1s are activated in tumors including colorectal carcinoma. However, how L1-retrotransposition (L1-RTP) is involved in gastrointestinal disorders remains to be elucidated. We hypothesized that L1-RTP in somatic cells might contribute to colitis-associated cancer (CAC). To address this, we employed an experimental model of CAC using transgenic L1-reporter mice carrying a human L1-EGFP reporter gene. Mice were subjected to repeated cycles of colitis induced by administration of dextran sodium sulfate (DSS) in drinking water with injection of carcinogen azoxymethane (AOM). L1-RTP levels were measured by a quantitative polymerase chain reaction targeting the newly inserted reporter EGFP in various tissues and cell types, including samples obtained by laser microdissection and cell sorting with flow cytometry. DNA methylation levels of the human L1 promoter were analyzed by bisulfite pyrosequencing. AOM+DSS-treated mice exhibited significantly higher levels of L1-RTP in whole colon tissue during the acute phase of colitis when compared with control naïve mice. L1-RTP levels in whole colon tissue were positively correlated with the histological severity of colitis and degree of neutrophil infiltration into the lamina propria (LP), but not with tumor development in the colon. L1-RTP was enriched in LP mesenchymal cells rather than epithelial cells (ECs), myeloid, or lymphoid cells. DNA methylation levels of the human L1 promoter region showed a negative correlation with L1-RTP levels. L1-RTP was absent from most tumors found in 22-week-old mice. In conclusion, we demonstrated that L1-RTP was induced in the mouse CAC mucosa in accordance with the acute inflammatory response; however, retrotransposition appears not to have direct relevance to colitis-induced cancer initiation.
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Affiliation(s)
- Takeshi Otsubo
- Department of Gastroenterology, Research Center for Hepatitis and Immunology, Research Institute, National Center for Global Health and Medicine, Ichikawa 272-8516, Japan
| | - Tadashi Okamura
- Section of Animal Models, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, 1-21-1, Toyama, Shinjuku-ku, 162-8655, Tokyo, Japan
| | - Teruki Hagiwara
- Department of Gastroenterology, Research Center for Hepatitis and Immunology, Research Institute, National Center for Global Health and Medicine, Ichikawa 272-8516, Japan
| | - Yukihito Ishizaka
- Department of Intractable Diseases, Research Institute, National Center for Global Health and Medicine, 1-21-1, Toyama, Shinjuku-ku, 162-8655, Tokyo, Japan
| | - Taeko Dohi
- Department of Gastroenterology, Research Center for Hepatitis and Immunology, Research Institute, National Center for Global Health and Medicine, Ichikawa 272-8516, Japan
- * E-mail: (TD); (YIK)
| | - Yuki I. Kawamura
- Department of Gastroenterology, Research Center for Hepatitis and Immunology, Research Institute, National Center for Global Health and Medicine, Ichikawa 272-8516, Japan
- * E-mail: (TD); (YIK)
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7
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Okudaira N, Ishizaka Y, Nishio H. Retrotransposition of long interspersed element 1 induced by methamphetamine or cocaine. J Biol Chem 2014; 289:25476-85. [PMID: 25053411 PMCID: PMC4162154 DOI: 10.1074/jbc.m114.559419] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Long interspersed element 1 (L1) is a retroelement constituting ∼17% of the human genome. A single human cell has 80–100 copies of L1 capable of retrotransposition (L1-RTP), ∼10% of which are “hot L1” copies, meaning they are primed for “jumping” within the genome. Recent studies demonstrated induction of L1 activity by drugs of abuse or low molecular weight compounds, but little is known about the underlying mechanism. The aim of this study was to identify the mechanism and effects of methamphetamine (METH) and cocaine on L1-RTP. Our results revealed that METH and cocaine induced L1-RTP in neuronal cell lines. This effect was found to be reverse transcriptase-dependent. However, METH and cocaine did not induce double-strand breaks. RNA interference experiments combined with add-back of siRNA-resistant cDNAs revealed that the induction of L1-RTP by METH or cocaine depends on the activation of cAMP response element-binding protein (CREB). METH or cocaine recruited the L1-encoded open reading frame 1 (ORF1) to chromatin in a CREB-dependent manner. These data suggest that the cellular cascades underlying METH- and cocaine-induced L1-RTP are different from those behind L1-RTP triggered by DNA damage; CREB is involved in drug-induced L1-RTP. L1-RTP caused by drugs of abuse is a novel type of genomic instability, and analysis of this phenomenon might be a novel approach to studying substance-use disorders.
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Affiliation(s)
- Noriyuki Okudaira
- From the Department of Legal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan and
| | - Yukihito Ishizaka
- Department of Intractable Diseases, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Hajime Nishio
- From the Department of Legal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan and
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8
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Mercury specifically induces LINE-1 activity in a human neuroblastoma cell line. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2013; 759:9-20. [PMID: 24240092 DOI: 10.1016/j.mrgentox.2013.07.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 06/25/2013] [Accepted: 07/05/2013] [Indexed: 11/21/2022]
Abstract
L1 retro-elements comprise 17% of the human genome. Approximately 100 copies of these autonomous mobile elements are active in our DNA and can cause mutations, gene disruptions, and genomic instability. Therefore, human cells control the activities of L1 elements, in order to prevent their deleterious effects through different mechanisms. However, some toxic agents increase the retrotransposition activity of L1 elements in somatic cells. In order to identify specific effects of neurotoxic metals on L1 activity in neuronal cells, we studied the effects of mercury and cobalt on L1-retroelement activity by measuring levels of cellular transcription, protein expression, and genomic retrotransposition in a neuroblastoma cell line compared with the effects in three non-neuronal cell lines. Our results show that mercury increased the expression of L1 RNA, the activity of the L1 5'UTR, and L1 retrotransposition exclusively in the neuroblastoma cell line but not in non-neuronal cell lines. However, cobalt increased the expression of L1 RNA in neuroblastoma cells, HeLa cells, and wild-type human fibroblasts, and also increased the activity of the L1 5'UTR as well as the SV40 promoter in HeLa cells but not in neuroblastoma cells. Exposure to cobalt did not result in increased retrotransposition activity in HeLa cells or neuroblastoma cells. We conclude that non-toxic levels of the neurotoxic agent mercury could influence DNA by increasing L1 activities, specifically in neuronal cells, and may make these cells susceptible to neurodegeneration over time.
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9
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Belan E. LINEs of evidence: noncanonical DNA replication as an epigenetic determinant. Biol Direct 2013; 8:22. [PMID: 24034780 PMCID: PMC3868326 DOI: 10.1186/1745-6150-8-22] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 09/06/2013] [Indexed: 12/17/2022] Open
Abstract
LINE-1 (L1) retrotransposons are repetitive elements in mammalian genomes. They are
capable of synthesizing DNA on their own RNA templates by harnessing reverse
transcriptase (RT) that they encode. Abundantly expressed full-length L1s and their
RT are found to globally influence gene expression profiles, differentiation state,
and proliferation capacity of early embryos and many types of cancer, albeit by yet
unknown mechanisms. They are essential for the progression of early development and
the establishment of a cancer-related undifferentiated state. This raises important
questions regarding the functional significance of L1 RT in these cell systems.
Massive nuclear L1-linked reverse transcription has been shown to occur in mouse
zygotes and two-cell embryos, and this phenomenon is purported to be DNA replication
independent. This review argues against this claim with the goal of understanding the
nature of this phenomenon and the role of L1 RT in early embryos and cancers.
Available L1 data are revisited and integrated with relevant findings accumulated in
the fields of replication timing, chromatin organization, and epigenetics, bringing
together evidence that strongly supports two new concepts. First, noncanonical
replication of a portion of genomic full-length L1s by means of L1 RNP-driven reverse
transcription is proposed to co-exist with DNA polymerase-dependent replication of
the rest of the genome during the same round of DNA replication in embryonic and
cancer cell systems. Second, the role of this mechanism is thought to be epigenetic;
it might promote transcriptional competence of neighboring genes linked to
undifferentiated states through the prevention of tethering of involved L1s to the
nuclear periphery. From the standpoint of these concepts, several hitherto
inexplicable phenomena can be explained. Testing methods for the model are
proposed.
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Affiliation(s)
- Ekaterina Belan
- Genetics Laboratory, Royal University Hospital, Saskatoon, SK S7N 0W8, Canada.
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10
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Terasaki N, Goodier JL, Cheung LE, Wang YJ, Kajikawa M, Kazazian HH, Okada N. In vitro screening for compounds that enhance human L1 mobilization. PLoS One 2013; 8:e74629. [PMID: 24040300 PMCID: PMC3770661 DOI: 10.1371/journal.pone.0074629] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 08/05/2013] [Indexed: 12/31/2022] Open
Abstract
The Long interspersed element 1 (LINE1 or L1) retrotransposon constitutes 17% of the human genome. There are currently 80-100 human L1 elements that are thought to be active in any diploid human genome. These elements can mobilize into new locations of the genome, resulting in changes in genomic information. Active L1s are thus considered to be a type of endogenous mutagen, and L1 insertions can cause disease. Certain stresses, such as gamma radiation, oxidative stress, and treatment with some agents, can induce transcription and/or mobilization of retrotransposons. In this study, we used a reporter gene assay in HepG2 cells to screen compounds for the potential to enhance the transcription of human L1. We assessed 95 compounds including genotoxic agents, substances that induce cellular stress, and commercially available drugs. Treatment with 15 compounds increased the L1 promoter activity by >1.5-fold (p<0.05) after 6 or 24 hours of treatment. In particular, genotoxic agents (benzo[a]pyrene, camptothecin, cytochalasin D, merbarone, and vinblastine), PPARα agonists (bezafibrate and fenofibrate), and non-steroidal anti-inflammatory drugs (diflunisal, flufenamic acid, salicylamide, and sulindac) induced L1 promoter activity. To examine their effects on L1 retrotransposition, we developed a high-throughput real-time retrotransposition assay using a novel secreted Gaussia luciferase reporter cassette. Three compounds (etomoxir, WY-14643, and salicylamide) produced a significant enhancement in L1 retrotransposition. This is the first study to report the effects of a wide variety of compounds on L1 transcription and retrotransposition. These results suggest that certain chemical- and drug-induced stresses might have the potential to cause genomic mutations by inducing L1 mobilization. Thus, the risk of induced L1 transcription and retrotransposition should be considered during drug safety evaluation and environmental risk assessments of chemicals.
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Affiliation(s)
- Natsuko Terasaki
- Department of Biological Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
| | - John L. Goodier
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Ling E. Cheung
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Yue J. Wang
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Masaki Kajikawa
- Department of Biological Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
| | - Haig H. Kazazian
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Norihiro Okada
- Department of Biological Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
- * E-mail:
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11
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Iijima K, Okudaira N, Tamura M, Doi A, Saito Y, Shimura M, Goto M, Matsunaga A, Kawamura YI, Otsubo T, Dohi T, Hoshino S, Kano S, Hagiwara S, Tanuma J, Gatanaga H, Baba M, Iguchi T, Yanagita M, Oka S, Okamura T, Ishizaka Y. Viral protein R of human immunodeficiency virus type-1 induces retrotransposition of long interspersed element-1. Retrovirology 2013; 10:83. [PMID: 23915234 PMCID: PMC3751050 DOI: 10.1186/1742-4690-10-83] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 07/18/2013] [Indexed: 01/04/2023] Open
Abstract
Background Viral protein R (Vpr), a protein of human immunodeficiency virus type-1 (HIV-1) with various biological functions, was shown to be present in the blood of HIV-1-positive patients. However, it remained unclear whether circulating Vpr in patients’ blood is biologically active. Here, we examined the activity of blood Vpr using an assay system by which retrotransposition of long interspersed element-1 (L1-RTP) was detected. We also investigated the in vivo effects of recombinant Vpr (rVpr) by administrating it to transgenic mice harboring human L1 as a transgene (hL1-Tg mice). Based on our data, we discuss the involvement of blood Vpr in the clinical symptoms of acquired immunodeficiency syndrome (AIDS). Results We first discovered that rVpr was active in induction of L1-RTP. Biochemical analyses revealed that rVpr-induced L1-RTP depended on the aryl hydrocarbon receptor, mitogen-activated protein kinases, and CCAAT/enhancer-binding protein β. By using a sensitive L1-RTP assay system, we showed that 6 of the 15 blood samples from HIV-1 patients examined were positive for induction of L1-RTP. Of note, the L1-RTP-inducing activity was blocked by a monoclonal antibody specific for Vpr. Moreover, L1-RTP was reproducibly induced in various organs, including the kidney, when rVpr was administered to hL1-Tg mice. Conclusions Blood Vpr is biologically active, suggesting that its monitoring is worthwhile for clarification of the roles of Vpr in the pathogenesis of AIDS. This is the first report to demonstrate a soluble factor in patients’ blood active for L1-RTP activity, and implies the involvement of L1-RTP in the development of human diseases.
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Affiliation(s)
- Kenta Iijima
- Department of Intractable Diseases, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan
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12
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Long interspersed element-1 is differentially regulated by food-borne carcinogens via the aryl hydrocarbon receptor. Oncogene 2012. [PMID: 23208499 PMCID: PMC3795476 DOI: 10.1038/onc.2012.516] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A single human cell contains more than 5.0 × 10(5) copies of long interspersed element-1 (L1), 80-100 of which are competent for retrotransposition (L1-RTP). Recent observations have revealed the presence of de novo L1 insertions in various tumors, but little is known about its mechanism. Here, we found that 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline (MeIQx), food-borne carcinogens that are present in broiled meats, induced L1-RTP. This induction was dependent on a cellular cascade comprising the aryl hydrocarbon receptor (AhR), a mitogen-activated protein kinase, and CCAAT/enhancer-binding protein β. Notably, these compounds exhibited differential induction of L1-RTP. MeIQx-induced L1-RTP was dependent on AhR nuclear translocator 1 (ARNT1), a counterpart of AhR required for gene expression in response to environmental pollutants. By contrast, PhIP-induced L1-RTP did not require ARNT1 but was dependent on estrogen receptor α (ERα) and AhR repressor. In vivo studies using transgenic mice harboring the human L1 gene indicated that PhIP-induced L1-RTP was reproducibly detected in the mammary gland, which is a target organ of PhIP-induced carcinoma. Moreover, picomolar levels of each compound induced L1-RTP, which is comparable to the PhIP concentration detected in human breast milk. Data suggest that somatic cells possess machineries that induce L1-RTP in response to the carcinogenic compounds. Together with data showing that micromolar levels of heterocyclic amines (HCAs) were non-genotoxic, our observations indicate that L1-RTP by environmental compounds is a novel type of genomic instability, further suggesting that analysis of L1-RTP by HCAs is a novel approach to clarification of modes of carcinogenesis.
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Nohara K, Tateishi Y, Suzuki T, Okamura K, Murai H, Takumi S, Maekawa F, Nishimura N, Kobori M, Ito T. Late-onset Increases in Oxidative Stress and Other Tumorigenic Activities and Tumors With a Ha-ras Mutation in the Liver of Adult Male C3H Mice Gestationally Exposed to Arsenic. Toxicol Sci 2012; 129:293-304. [DOI: 10.1093/toxsci/kfs203] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Ishizaka Y, Okudaira N, Tamura M, Iijima K, Shimura M, Goto M, Okamura T. Modes of retrotransposition of long interspersed element-1 by environmental factors. Front Microbiol 2012; 3:191. [PMID: 22666219 PMCID: PMC3364524 DOI: 10.3389/fmicb.2012.00191] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 05/10/2012] [Indexed: 11/13/2022] Open
Abstract
Approximately 42% of the human genome is composed of endogenous retroelements, and the major retroelement component, long interspersed element-1 (L1), comprises ∼17% of the total genome. A single human cell has more than 5 × 10(5) copies of L1, 80∼100 copies of which are competent for retrotransposition (RTP). Notably, L1 can induce RTP of other retroelements, such as Alu and SVA, and is believed to function as a driving force of evolution. Although L1-RTP during early embryogenesis has been highlighted in the literature, recent observations revealed that L1-RTP also occurs in somatic cells. However, little is known about how environmental factors induce L1-RTP. Here, we summarize our current understanding of the mechanism of L1-RTP in somatic cells. We have focused on the mode of L1-RTP that is dependent on the basic helix-loop-helix/per-arnt-sim (bHLH/PAS) family of transcription factors. Along with the proposed function of bHLH/PAS proteins in environmental adaptation, we discuss the functional linking of L1-RTP and bHLH/PAS proteins for environmental adaptation and evolution.
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Affiliation(s)
- Yukihito Ishizaka
- Department of Intractable Diseases, National Center for Global Health and Medicine Tokyo, Japan
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