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Saeliw T, Kanlayaprasit S, Thongkorn S, Songsritaya K, Sanannam B, Sae-Lee C, Jindatip D, Hu VW, Sarachana T. Epigenetic Gene-Regulatory Loci in Alu Elements Associated with Autism Susceptibility in the Prefrontal Cortex of ASD. Int J Mol Sci 2023; 24:ijms24087518. [PMID: 37108679 PMCID: PMC10139202 DOI: 10.3390/ijms24087518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/07/2023] [Accepted: 04/17/2023] [Indexed: 04/29/2023] Open
Abstract
Alu elements are transposable elements that can influence gene regulation through several mechanisms; nevertheless, it remains unclear whether dysregulation of Alu elements contributes to the neuropathology of autism spectrum disorder (ASD). In this study, we characterized transposable element expression profiles and their sequence characteristics in the prefrontal cortex tissues of ASD and unaffected individuals using RNA-sequencing data. Our results showed that most of the differentially expressed transposable elements belong to the Alu family, with 659 loci of Alu elements corresponding to 456 differentially expressed genes in the prefrontal cortex of ASD individuals. We predicted cis- and trans-regulation of Alu elements to host/distant genes by conducting correlation analyses. The expression level of Alu elements correlated significantly with 133 host genes (cis-regulation, adjusted p < 0.05) associated with ASD as well as the cell survival and cell death of neuronal cells. Transcription factor binding sites in the promoter regions of differentially expressed Alu elements are conserved and associated with autism candidate genes, including RORA. COBRA analyses of postmortem brain tissues showed significant hypomethylation in global methylation analyses of Alu elements in ASD subphenotypes as well as DNA methylation of Alu elements located near the RNF-135 gene (p < 0.05). In addition, we found that neuronal cell density, which was significantly increased (p = 0.042), correlated with the expression of genes associated with Alu elements in the prefrontal cortex of ASD. Finally, we determined a relationship between these findings and the ASD severity (i.e., ADI-R scores) of individuals with ASD. Our findings provide a better understanding of the impact of Alu elements on gene regulation and molecular neuropathology in the brain tissues of ASD individuals, which deserves further investigation.
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Affiliation(s)
- Thanit Saeliw
- The Ph.D. Program in Clinical Biochemistry and Molecular Medicine, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand
| | - Songphon Kanlayaprasit
- Systems Neuroscience of Autism and Psychiatric Disorders (SYNAPS) Research Unit, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand
| | - Surangrat Thongkorn
- The Ph.D. Program in Clinical Biochemistry and Molecular Medicine, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand
- Department of Biotechnology and Biomedicine (DTU Bioengineering), Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Kwanjira Songsritaya
- The M.Sc. Program in Clinical Biochemistry and Molecular Medicine, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand
| | - Bumpenporn Sanannam
- Division of Anatomy, Department of Preclinical Science, Faculty of Medicine, Thammasat University, Pathumthani 12120, Thailand
| | - Chanachai Sae-Lee
- Research Division, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Department of Clinical Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Depicha Jindatip
- Systems Neuroscience of Autism and Psychiatric Disorders (SYNAPS) Research Unit, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand
- Department of Anatomy, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
| | - Valerie W Hu
- Department of Biochemistry and Molecular Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC 20052, USA
| | - Tewarit Sarachana
- Systems Neuroscience of Autism and Psychiatric Disorders (SYNAPS) Research Unit, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand
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Liu S, Morihiro K, Takeuchi F, Li Y, Okamoto A. Interstrand crosslinking oligonucleotides elucidate the effect of metal ions on the methylation status of repetitive DNA elements. Front Chem 2023; 11:1122474. [PMID: 36711237 PMCID: PMC9881727 DOI: 10.3389/fchem.2023.1122474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 01/02/2023] [Indexed: 01/15/2023] Open
Abstract
DNA methylation plays an important physiological function in cells, and environmental changes result in fluctuations in DNA methylation levels. Metal ions have become both environmental and health concerns, as they have the potential to disrupt the genomic DNA methylation status, even on specific sequences. In the current research, the methylation status of two typical repetitive DNA elements, i.e., long-interspersed nuclear element-1 (LINE-1) and alpha satellite (α-sat), was imaged and assessed using methylation-specific fluorescence in situ hybridization (MeFISH). This technique elucidated the effect of several metal ions on the methylation levels of repetitive DNA sequences. The upregulation and downregulation of the methylation levels of repetitive DNA elements by various metal ions were confirmed and depended on their concentration. This is the first example to investigate the effects of metal ions on DNA methylation in a sequence-specific manner.
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Affiliation(s)
- Shan Liu
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Kunihiko Morihiro
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Fumika Takeuchi
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Yufeng Li
- The Key Laboratory of Molecular Oncology of Hebei Province, Tangshan People’s Hospital, Tangshan, Hebei, China
| | - Akimitsu Okamoto
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan,*Correspondence: Akimitsu Okamoto,
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Jiménez-Garza O, Ghosh M, Barrow TM, Godderis L. Toxicomethylomics revisited: A state-of-the-science review about DNA methylation modifications in blood cells from workers exposed to toxic agents. Front Public Health 2023; 11:1073658. [PMID: 36891347 PMCID: PMC9986591 DOI: 10.3389/fpubh.2023.1073658] [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: 10/18/2022] [Accepted: 01/25/2023] [Indexed: 02/22/2023] Open
Abstract
Introduction Epigenetic marks have been proposed as early changes, at the subcellular level, in disease development. To find more specific biomarkers of effect in occupational exposures to toxicants, DNA methylation studies in peripheral blood cells have been performed. The goal of this review is to summarize and contrast findings about DNA methylation in blood cells from workers exposed to toxicants. Methods A literature search was performed using PubMed and Web of Science. After first screening, we discarded all studies performed in vitro and in experimental animals, as well as those performed in other cell types other than peripheral blood cells. Results: 116 original research papers met the established criteria, published from 2007 to 2022. The most frequent investigated exposures/labor group were for benzene (18.9%) polycyclic aromatic hydrocarbons (15.5%), particulate matter (10.3%), lead (8.6%), pesticides (7.7%), radiation (4.3%), volatile organic compound mixtures (4.3%), welding fumes (3.4%) chromium (2.5%), toluene (2.5%), firefighters (2.5%), coal (1.7%), hairdressers (1.7%), nanoparticles (1.7%), vinyl chloride (1.7%), and others. Few longitudinal studies have been performed, as well as few of them have explored mitochondrial DNA methylation. Methylation platforms have evolved from analysis in repetitive elements (global methylation), gene-specific promoter methylation, to epigenome-wide studies. The most reported observations were global hypomethylation as well as promoter hypermethylation in exposed groups compared to controls, while methylation at DNA repair/oncogenes genes were the most studied; studies from genome-wide studies detect differentially methylated regions, which could be either hypo or hypermethylated. Discussion Some evidence from longitudinal studies suggest that modifications observed in cross-sectional designs may be transitory; then, we cannot say that DNA methylation changes are predictive of disease development due to those exposures. Conclusion Due to the heterogeneity in the genes studied, and scarcity of longitudinal studies, we are far away from considering DNA methylation changes as biomarkers of effect in occupational exposures, and nor can we establish a clear functional or pathological correlate for those epigenetic modifications associated with the studied exposures.
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Affiliation(s)
- Octavio Jiménez-Garza
- Health Sciences Institute, Autonomous University of Hidalgo State, Pachuca Hidalgo, Mexico
| | - Manosij Ghosh
- Environment and Health Department, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Timothy M Barrow
- Faculty of Health Sciences and Wellbeing, University of Sunderland, Sunderland, United Kingdom
| | - Lode Godderis
- Environment and Health Department, Katholieke Universiteit Leuven, Leuven, Belgium
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Sae-Lee C, Barrow TM, Colicino E, Choi SH, Rabanal-Ruiz Y, Green D, Korolchuk VI, Mathers JC, Byun HM. Genomic targets and selective inhibition of DNA methyltransferase isoforms. Clin Epigenetics 2022; 14:103. [PMID: 35987848 PMCID: PMC9392947 DOI: 10.1186/s13148-022-01325-4] [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: 03/03/2022] [Accepted: 08/11/2022] [Indexed: 11/10/2022] Open
Abstract
Background DNA methylation in the human genome is established and maintained by DNA methyltransferases (DNMTs). DNMT isoforms show differential expression by cell lineage and during development, but much remains to be elucidated about their shared and unique genomic targets. Results We examined changes in the epigenome following overexpression of 13 DNMT isoforms in HEK293T cells. We observed increased methylation (Δβ > 0.2) at 43,405 CpG sites, with expression of DNMT3A2, DNMTΔ3B4 and DNMTΔ3B2 associated with the greatest impact. De novo methylation occurred primarily within open sea regions and at loci with intermediate methylation levels (β: 0.2–0.6). 53% of differentially methylated loci showed specificity towards a single DNMT subfamily, primarily DNMTΔ3B and DNMT3A and 39% towards a single isoform. These loci were significantly enriched for pathways related to neuronal development (DNMTΔ3B4), calcium homeostasis (DNMTΔ3B3) and ion transport (DNMT3L). Repetitive elements did not display differential sensitivity to overexpressed DNMTs, but hypermethylation of Alu elements was associated with their evolutionary age following overexpression of DNMT3A2, DNMT3B1, DNMT3B2 and DNMT3L. Differential methylation (Δβ > 0.1) was observed at 121 of the 353 loci associated with the Horvath ‘epigenetic clock’ model of ageing, with 51 showing isoform specificity, and was associated with reduction of epigenetic age by 5–15 years following overexpression of seven isoforms. Finally, we demonstrate the potential for dietary constituents to modify epigenetic marks through isoform-specific inhibition of methylation activity. Conclusions Our results provide insight into regions of the genome methylated uniquely by specific DNMT isoforms and demonstrate the potential for dietary intervention to modify the epigenome. Supplementary Information The online version contains supplementary material available at 10.1186/s13148-022-01325-4.
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Feng Y, Liu T, Xu S, Ren Y, Ge Y, Yin L, Pu Y, Liang G. The role of N6-methyladenosine methylation in environmental exposure-induced health damage. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:69153-69175. [PMID: 35951238 DOI: 10.1007/s11356-022-22093-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
The health risks caused by environmental pollution have long been of substantial concern. With the development of epigenetics, a large number of studies have demonstrated that N6-methyladenosine (m6A) modification is involved in the regulation of various important life activities associated with various diseases. Recent studies have revealed that m6A plays a key role in health damage caused by environmental exposure by regulating post-transcriptional gene expression. Therefore, our study outlined the effects of environmental pollutant exposure on m6A methylation and its regulator levels. Moreover, we found that m6A methylation modifications were involved in the development of various health damages by regulating important life activities in vivo, such as reactive oxygen species imbalance, apoptosis, epithelial-mesenchymal transition (EMT), and inflammatory processes. More importantly, we delved into the regulatory mechanisms of m6A methylation dysregulation in environmental pollution-induced diseases. Finally, by examining the published literature, we found that methyltransferase-like protein 3 (METTL3) and fat mass- and obesity-associated protein (FTO) were potentially used as biomarkers of health damage induced by particulate matter exposure and heavy metal exposure, respectively. The current studies on regulators of METTL3 and FTO were more promising to bring new perspectives for the treatment of environmental health-related diseases.
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Affiliation(s)
- Yanlu Feng
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, 210009, Jiangsu, People's Republic of China
| | - Tong Liu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, 210009, Jiangsu, People's Republic of China
| | - Siyi Xu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, 210009, Jiangsu, People's Republic of China
| | - Yiyi Ren
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, 210009, Jiangsu, People's Republic of China
| | - Yiling Ge
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, 210009, Jiangsu, People's Republic of China
| | - Lihong Yin
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, 210009, Jiangsu, People's Republic of China
| | - Yuepu Pu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, 210009, Jiangsu, People's Republic of China
| | - Geyu Liang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, 210009, Jiangsu, People's Republic of China.
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Chesnokova E, Beletskiy A, Kolosov P. The Role of Transposable Elements of the Human Genome in Neuronal Function and Pathology. Int J Mol Sci 2022; 23:5847. [PMID: 35628657 PMCID: PMC9148063 DOI: 10.3390/ijms23105847] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 12/13/2022] Open
Abstract
Transposable elements (TEs) have been extensively studied for decades. In recent years, the introduction of whole-genome and whole-transcriptome approaches, as well as single-cell resolution techniques, provided a breakthrough that uncovered TE involvement in host gene expression regulation underlying multiple normal and pathological processes. Of particular interest is increased TE activity in neuronal tissue, and specifically in the hippocampus, that was repeatedly demonstrated in multiple experiments. On the other hand, numerous neuropathologies are associated with TE dysregulation. Here, we provide a comprehensive review of literature about the role of TEs in neurons published over the last three decades. The first chapter of the present review describes known mechanisms of TE interaction with host genomes in general, with the focus on mammalian and human TEs; the second chapter provides examples of TE exaptation in normal neuronal tissue, including TE involvement in neuronal differentiation and plasticity; and the last chapter lists TE-related neuropathologies. We sought to provide specific molecular mechanisms of TE involvement in neuron-specific processes whenever possible; however, in many cases, only phenomenological reports were available. This underscores the importance of further studies in this area.
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Affiliation(s)
- Ekaterina Chesnokova
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences, 117485 Moscow, Russia; (A.B.); (P.K.)
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Vandewege MW, Patt RN, Merriman DK, Ray DA, Hoffmann FG. The PIWI/piRNA response is relaxed in a rodent that lacks mobilizing transposable elements. RNA (NEW YORK, N.Y.) 2022; 28:609-621. [PMID: 35064043 PMCID: PMC8925971 DOI: 10.1261/rna.078862.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Transposable elements (TEs) are genomic parasites that can propagate throughout host genomes. Mammalian genomes are typically dominated by LINE retrotransposons and their associated SINEs, and germline mobilization is a challenge to genome integrity. There are defenses against TE proliferation and the PIWI/piRNA defense is among the most well understood. However, the PIWI/piRNA system has been investigated largely in animals with actively mobilizing TEs and it is unclear how the PIWI/piRNA system functions in the absence of mobilizing TEs. The 13-lined ground squirrel provides the opportunity to examine PIWI/piRNA and TE dynamics within the context of minimal, and possibly nonexistent, TE accumulation. To do so, we compared the PIWI/piRNA dynamics in squirrels to observations from the rabbit and mouse. Despite a lack of young insertions in squirrels, TEs were still actively transcribed at higher levels compared to mouse and rabbit. All three Piwi genes were not expressed, prior to P8 in squirrel testis, and there was little TE expression change with the onset of Piwi expression. We also demonstrated there was not a major expression change in the young squirrel LINE families in the transition from juvenile to adult testis in contrast to young mouse and rabbit LINE families. These observations lead us to conclude that PIWI suppression, was weaker for squirrel LINEs and SINEs and did not strongly reduce their transcription. We speculate that, although the PIWI/piRNA system is adaptable to novel TE threats, transcripts from TEs that are no longer threatening receive less attention from PIWI proteins.
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Affiliation(s)
- Michael W Vandewege
- Department of Biology, Eastern New Mexico University, Portales, New Mexico 88130, USA
| | - Roy N Patt
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, Texas 78245-0549, USA
| | - Dana K Merriman
- Department of Biology, University of Wisconsin Oshkosh, Oshkosh, Wisconsin 54901, USA
| | - David A Ray
- Department of Biological Sciences, Texas Tech University, Lubbock, Texas 79409, USA
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, Mississippi 39762, USA
- Institute of Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, Mississippi 39762, USA
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Lee JY, Lee WK, Kim DS. Particulate matter-induced hypomethylation of Alu and LINE1 in normal human bronchial epithelial cells and epidermal keratinocytes. Genes Environ 2022; 44:8. [PMID: 35172897 PMCID: PMC8848652 DOI: 10.1186/s41021-022-00235-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 01/20/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Airborne particulate matter (PM), a complex mixture of organic and inorganic compounds, is a major public health concern due to its adverse health effects. Understanding the biological action of PM is of particular importance in the improvement of public health. Differential methylation of repetitive elements (RE) by PM might have severe consequences for the structural integrity of the genome and on transcriptional activity, thereby affecting human health. This study aimed to evaluate the effect of inhaled and non-inhaled PM (PM2.5, PM10, and PM10-PAH) exposure on DNA methylation. We quantitatively measured the methylation content of Alu and LINE1 in PM-treated normal human bronchial epithelial cells (NHBE) and normal human epidermal keratinocytes (NHEK) by using whole-genome bisulfite sequencing and pyrosequencing. RESULTS All PMs exposure significantly lowered Alu and LINE1 methylation in both cells than in mock-treated controls. Hypomethylation was more prominent in PM10-PAH exposed-NHBE and PM10 exposed-NHEK. Alu and LINE1 methylation change exhibited different sensitivity according to the subfamily evolutionary ages, with stronger effects on the oldest L1-M and Alu J in NHBE, and oldest L1-M and youngest Alu S in NHEK. CONCLUSIONS These results demonstrate that the differential susceptibility of PM-induced hypomethylation of Alu and LINE1 depends upon RE evolutionary age and PM type.
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Affiliation(s)
- Ji Yun Lee
- Department of Anatomy and BK21 Plus KNU Biomedical Convergence Program, Daegu, Republic of Korea
| | - Won Kee Lee
- Preventive Medicine, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Dong Sun Kim
- Department of Anatomy and BK21 Plus KNU Biomedical Convergence Program, Daegu, Republic of Korea.
- Department of Anatomy, School of Medicine, Kyungpook National University, 2-101 Dongin-dong, Jung-gu, 702-422, Daegu, Republic of Korea.
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Mendes CC, Zampieri BL, Arantes LMRB, Melendez ME, Biselli JM, Carvalho AL, Eberlin MN, Riccio MF, Vannucchi H, Carvalho VM, Goloni-Bertollo EM, Pavarino ÉC. One-carbon metabolism and global DNA methylation in mothers of individuals with Down syndrome. Hum Cell 2021; 34:1671-1681. [PMID: 34410622 DOI: 10.1007/s13577-021-00586-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/26/2021] [Indexed: 10/20/2022]
Abstract
Down syndrome (DS) is the most common chromosomal disorder, resulting from the failure of normal chromosome 21 segregation. Studies have suggested that impairments within the one-carbon metabolic pathway can be of relevance for the global genome instability observed in mothers of individuals with DS. Based on the association between global DNA hypomethylation, genome instability, and impairments within the one-carbon metabolic pathway, the present study aimed to identify possible predictors, within the one-carbon metabolism, of global DNA methylation, measured by methylation patterns of LINE-1 and Alu repetitive sequences, in mothers of individuals with DS and mothers of individuals without the syndrome. In addition, we investigated one-carbon genetic polymorphisms and metabolites as maternal predisposing factors for the occurrence of trisomy 21 in children. Eighty-three samples of mothers of children with DS with karyotypically confirmed free trisomy 21 (case group) and 84 of mothers who had at least one child without DS or any other aneuploidy were included in the study. Pyrosequencing assays were performed to access global methylation. The results showed that group affiliation (case or control), betaine-homocysteine methyltransferase (BHMT) G742A and transcobalamin 2 (TCN2) C776G polymorphisms, and folate concentration were identified as predictors of global Alu DNA methylation values. In addition, thymidylate synthase (TYMS) 28-bp repeats 2R/3R or 3R/3R genotypes are independent maternal predisposing factors for having a child with DS. This study adds evidence that supports the association of impairments in the one-carbon metabolism, global DNA methylation, and the possibility of having a child with DS.
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Affiliation(s)
- Cristiani Cortez Mendes
- Unidade de Pesquisa em Genética e Biologia Molecular-UPGEM, Departamento de Biologia Molecular, Faculdade de Medicina de São José do Rio Preto-FAMERP, São José do Rio Preto, São Paulo, Brazil
| | | | | | - Matias Eliseo Melendez
- Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, São Paulo, Brazil
| | - Joice Matos Biselli
- Universidade Estadual Paulista Júlio de Mesquita Filho, Instituto de Biociências, Letras e Ciências Exatas de São José do Rio Preto, Departamento de Ciências Biológicas, São José do Rio Preto, São Paulo, Brazil
| | - André Lopes Carvalho
- Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, São Paulo, Brazil
| | - Marcos Nogueira Eberlin
- Universidade Presbiteriana Mackenzie, Discovery-Mackenzie-Núcleo Mackenzie de Pesquisa, Núcleo Mackenzie de Pesquisas em Ciência, Fé e Sociedade, São Paulo, São Paulo, Brazil
| | | | - Hélio Vannucchi
- Laboratório de Nutrição, Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto-USP, Ribeirão Preto, São Paulo, Brazil
| | | | - Eny Maria Goloni-Bertollo
- Unidade de Pesquisa em Genética e Biologia Molecular-UPGEM, Departamento de Biologia Molecular, Faculdade de Medicina de São José do Rio Preto-FAMERP, São José do Rio Preto, São Paulo, Brazil
| | - Érika Cristina Pavarino
- Unidade de Pesquisa em Genética e Biologia Molecular-UPGEM, Departamento de Biologia Molecular, Faculdade de Medicina de São José do Rio Preto-FAMERP, São José do Rio Preto, São Paulo, Brazil.
- , Av. Brigadeiro Faria Lima, 5416, Vila São Pedro, São José do Rio Preto, São Paulo, 15090-000, Brazil.
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Barrow TM, Wong Doo N, Milne RL, Giles GG, Willmore E, Strathdee G, Byun HM. Analysis of retrotransposon subfamily DNA methylation reveals novel early epigenetic changes in chronic lymphocytic leukemia. Haematologica 2021; 106:98-110. [PMID: 31919093 PMCID: PMC7776340 DOI: 10.3324/haematol.2019.228478] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 01/07/2020] [Indexed: 11/30/2022] Open
Abstract
Retrotransposons such as LINE-1 and Alu comprise >25% of the human genome. While global hypomethylation of these elements has been widely reported in solid tumours, their epigenetic dysregulation is yet to be characterised in chronic lymphocytic leukemia (CLL), and there has been scant consideration of their evolutionary history that mediates sensitivity to hypomethylation. Here, we developed an approach for locus- and evolutionary subfamily-specific analysis of retrotransposons using the Illumina Infinium Human Methylation 450K microarray platform, which we applied to publicly-available datasets from CLL and other haematological malignancies. We identified 9,797 microarray probes mapping to 117 LINE-1 subfamilies and 13,130 mapping to 37 Alu subfamilies. Of these, 10,782 were differentially methylated (PFDR<0.05) in CLL patients (n=139) compared with healthy individuals (n=14), with enrichment at enhancers (P=0.002). Differential methylation was associated with evolutionary age of LINE-1 (r2=0.31, P=0.003) and Alu (r2=0.74, P=0.002) elements, with greater hypomethylation of older subfamilies (L1M, AluJ). Locus-specific hypomethylation was associated with differential expression of proximal genes, including DCLK2, HK1, ILRUN, TANK, TBCD, TNFRSF1B and TXNRD2, with higher expression of DCLK2 and TNFRSF1B associated with reduced patient survival. Hypomethylation at nine loci was highly frequent in CLL (>90% patients) but not observed in healthy individuals or other leukaemias, and was detectable in blood samples taken prior to CLL diagnosis in 9 of 82 individuals from the Melbourne Collaborative Cohort Study. Our results demonstrate differential methylation of retrotransposons in CLL by their evolutionary heritage that modulates expression of proximal genes.
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Affiliation(s)
- Timothy M Barrow
- Faculty of Health Sciences and Wellbeing, University of Sunderland, Sunderland, United Kingdom
| | - Nicole Wong Doo
- Cancer Epidemiology Division, Cancer Council Victoria, Melbourne, Australia
| | - Roger L Milne
- Cancer Epidemiology Division, Cancer Council Victoria, Melbourne, Australia
| | - Graham G Giles
- Cancer Epidemiology Division, Cancer Council Victoria, Melbourne, Australia
| | - Elaine Willmore
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gordon Strathdee
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Hyang-Min Byun
- Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
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Akemann C, Meyer DN, Gurdziel K, Baker TR. TCDD-induced multi- and transgenerational changes in the methylome of male zebrafish gonads. ENVIRONMENTAL EPIGENETICS 2020; 6:dvaa010. [PMID: 33214906 PMCID: PMC7660120 DOI: 10.1093/eep/dvaa010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 06/01/2020] [Accepted: 06/09/2020] [Indexed: 05/23/2023]
Abstract
The legacy endocrine disrupting chemical and aryl hydrocarbon receptor agonist, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is produced as a byproduct of industrial processes and causes adverse health effects ranging from skin irritation to cancer. TCDD endpoints are also observed in subsequent, unexposed generations; however, the mechanisms of these multi- and transgenerational effects are unknown. We hypothesized an epigenetic mechanism, specifically DNA methylation for the transgenerational, male-mediated reproductive effects of developmental TCDD exposure. Using whole genome bisulfite sequencing, we evaluated DNA methylation changes in three generations of zebrafish, the first of which was exposed to TCDD during sexual development at 50 ppt for 1 h at both 3- and 7-week post-fertilization. We discovered that TCDD induces multi- and transgenerational methylomic changes in testicular tissue from zebrafish with decreased reproductive capacity, but most significantly in the indirectly exposed F1 generation. In comparing differentially methylated genes to concurrent transcriptomic changes, we identified several genes and pathways through which transgenerational effects of low level TCDD exposure are likely inherited. These include significant differential methylation of genes involved in reproduction, endocrine function, xenobiotic metabolism, and epigenetic processing. Notably, a number of histone modification genes were both differentially methylated and expressed in all generations, and many differentially methylated genes overlapped between multiple generations. Collectively, our results suggest that DNA methylation is a promising mechanism to explain male-mediated transgenerational reproductive effects of TCDD exposure in zebrafish, and these effects are likely inherited through integration of multiple epigenetic pathways.
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Affiliation(s)
- Camille Akemann
- Department of Pharmacology, Wayne State University, Detroit, 540 E. Canfield, Detroit, MI, 48201, USA
- Institute of Environmental Health Sciences, Wayne State University, Detroit, 5135 Woodward Ave. Detroit, MI, 48202, USA
| | - Danielle N Meyer
- Department of Pharmacology, Wayne State University, Detroit, 540 E. Canfield, Detroit, MI, 48201, USA
- Institute of Environmental Health Sciences, Wayne State University, Detroit, 5135 Woodward Ave. Detroit, MI, 48202, USA
| | - Katherine Gurdziel
- School of Medicine, Applied Genome Technology Center, Wayne State University, Detroit, 261 E Hancock St, Detroit, MI, 4820, USA
| | - Tracie R Baker
- Department of Pharmacology, Wayne State University, Detroit, 540 E. Canfield, Detroit, MI, 48201, USA
- Institute of Environmental Health Sciences, Wayne State University, Detroit, 5135 Woodward Ave. Detroit, MI, 48202, USA
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12
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DNA methylation patterns of LINE-1 and Alu for pre-symptomatic dementia in type 2 diabetes. PLoS One 2020; 15:e0234578. [PMID: 32525932 PMCID: PMC7289438 DOI: 10.1371/journal.pone.0234578] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 05/28/2020] [Indexed: 12/13/2022] Open
Abstract
The identification of early markers of dementia is important for higher-risk populations such as those with type 2 diabetes (T2D). Retrotransposons, including long interspersed nuclear element 1 (LINE-1) and Alu, comprise ~40% of the human genome. Although dysregulation of these retrotransposons can induce aberrant gene regulation and genomic instability, their role in the development of pre-symptomatic dementia (PSD) among T2D patients is unknown. Here, we examined locus-specific changes in LINE-1 and Alu methylation in PSD and the potential to offset these changes via supplementation with folate and vitamin B12. We interrogated DNA methylation patterns corresponding to 22,352 probes for LINE-1 and Alu elements using publicly-available Illumina Infinium 450K methylation datasets from i) an 18-month prospective study in 28 T2D patients (GSE62003) and ii) an intervention study in which 44 individuals were supplemented with folic acid (400 μg/day) and vitamin B12 (500 μg/day) over two years (GSE74548). We identified 714 differentially methylated positions (DMP) mapping to retrotransposons in T2D patients who developed PSD in comparison to those who did not (PFDR < 0.05), comprised of 2.4% (228 probes) of all LINE-1 probes and 3.8% (486 probes) of all Alu probes. These loci were enriched in genes with functions related to Alzheimer's disease and cognitive decline, including GNB5, GNG7 and PKN3 (p < 0.05). In older individuals supplemented with folate/vitamin B12, 85 (11.9%) PSD retrotransposon loci showed significant changes in methylation (p < 0.05): participants with the MTHFR CC genotype predominantly showed hypermethylation at these loci, while hypomethylation was observed more frequently in those with the TT genotype. In T2D patients, LINE-1 and Alu elements are differentially methylated in PSD in a locus-specific manner and may offer clinical utility in monitoring risk of dementia. Further work is required to examine the potential for dietary supplementation in lowering the risk of PSD.
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13
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Cayir A, Barrow TM, Guo L, Byun HM. Exposure to environmental toxicants reduces global N6-methyladenosine RNA methylation and alters expression of RNA methylation modulator genes. ENVIRONMENTAL RESEARCH 2019; 175:228-234. [PMID: 31146095 DOI: 10.1016/j.envres.2019.05.011] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 04/20/2019] [Accepted: 05/10/2019] [Indexed: 06/09/2023]
Abstract
The epitranscriptome comprises more than 100 forms of RNA modifications. Of these, N6-methyladenosine (m6A) is the most abundantform of RNA methylation, with roles in modulating mRNA transcript processing and regulation. The aims of the study weretoexamine changes inm6A RNA methylation in A549 lung epithelial cells in response to environmental toxicants, anddifferential gene expression of m6A modulator genes ('readers', 'writers' and 'erasers') in human subjects exposed toparticulate matter (PM) and in lung cancer tissueusing publicly-available microarray datasets. Global m6A methylation levelsweremeasured in total RNA after exposuretotwo carcinogens (PM and sodium arsenite) for 24- and 48-h, and totwo endocrine disruptors (bisphenol A and vinclozolin)for 24-h.Global m6A methylation level significantly decreased with exposure to >62 μg/mlPM, >1 μM sodium arsenite, >1 μM bisphenol A (BPA), and0.1 μM vinclozolin. In an analysis of a published dataset derived from a population study, we observed that m6A writers (METTL3 and WTAP), erasers (FTO and ALKBH5) and readers (HNRPC) showed significantly higher expression among participants in the high-PM2.5exposure group compared to those in the low-exposure control group (all p < 0.05). Further, the m6A writer METTL3shows reduced expression in lung tumors in comparison to normal lung epithelia (p < 0.0001). Our findings reveal that m6A RNA methylation can be modified by exposure to environmental toxicants, and exposure to particulate matter is associated with differential expression level of m6A RNA methylation modification machinery.
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Affiliation(s)
- Akin Cayir
- Vocational Health College, Canakkale Onsekiz Mart University, Canakkale, Turkey; Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom.
| | - Timothy M Barrow
- Faculty of Health Sciences and Wellbeing, University of Sunderland, Sunderland, United Kingdom
| | - Liqiong Guo
- Tianjin Key Laboratory of Environment, Nutrition and Public Health; Center for International Collaborative Research on Environment, Nutrition and Public Health; Department of Occupational & Environmental Health, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Hyang-Min Byun
- Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
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14
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Leso V, Vetrani I, Della Volpe I, Nocera C, Iavicoli I. Welding Fume Exposure and Epigenetic Alterations: A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16101745. [PMID: 31108839 PMCID: PMC6571852 DOI: 10.3390/ijerph16101745] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/11/2019] [Accepted: 05/13/2019] [Indexed: 11/16/2022]
Abstract
Epigenetics are heritable changes in gene expression not coded in the DNA sequence, which stand at the interface between the genome, environmental exposure and development. From an occupational health perspective, epigenetic variants may link workplace exposures and health effects. Therefore, this review aimed to overview possible epigenetic effects induced by welding fumes on exposed workers and health implications. A systematic search was performed on Pubmed, Scopus, and ISI Web of Knowledge databases. DNA methylation changes have been reported in genes responsible for the cardiac autonomic function and coagulation, i.e., LINE-1, GPR133 and F2RL3, in mitochondrial-DNA-sequences involved in the regulation of energy-generation/redox-signaling, as well as in inflammatory activated genes, i.e., iNOS. However, the limited number of retrieved articles, their cross-sectional nature, the lack of a suitable qualitative-quantitative exposure assessment, and the heterogeneity of biological-outcomes investigated, prevent the extrapolation of a definite causal relationship between welding fumes and epigenetic phenomena. Future studies should clarify the function of such epigenetic alterations as possible markers of occupational exposure and early effect, dose-response relationships, and underlying molecular mechanisms. Overall, this may be helpful to guide suitable risk assessment and management strategies to protect the health of workers exposed to welding fumes.
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Affiliation(s)
- Veruscka Leso
- Section of Occupational Medicine, Department of Public Health, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy.
| | - Ilaria Vetrani
- Section of Occupational Medicine, Department of Public Health, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy.
| | - Ilaria Della Volpe
- Section of Occupational Medicine, Department of Public Health, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy.
| | - Caterina Nocera
- Section of Occupational Medicine, Department of Public Health, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy.
| | - Ivo Iavicoli
- Section of Occupational Medicine, Department of Public Health, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy.
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15
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Akemann C, Meyer DN, Gurdziel K, Baker TR. Developmental Dioxin Exposure Alters the Methylome of Adult Male Zebrafish Gonads. Front Genet 2019; 9:719. [PMID: 30687390 PMCID: PMC6336703 DOI: 10.3389/fgene.2018.00719] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 12/21/2018] [Indexed: 01/20/2023] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental toxicant and endocrine disrupting compound with reproductive and developmental effects in humans and model organisms, including zebrafish. Our previous microarray and histological studies found defects in spermatogenesis and fertility of zebrafish in response to acute developmental TCDD exposure. These effects are apparent following exposure during reproductive development, modeling fetal basis of adult-onset disease. Some outcomes of these previous studies (reduced fertility, changes in sex ratio, transcriptomic alterations) are also transgenerational – persisting to unexposed generations – through the male germline. We hypothesized that DNA methylation could be a possible mechanism for these reproductive effects and performed whole genome bisulfite sequencing (WGBS), which identifies whole genome DNA methylation status at the base pair level, on testes of adult zebrafish exposed to TCDD (two separate hour-long exposures to 50 pg/mL TCDD at 3 and 7 weeks post fertilization). In response to TCDD exposure, multiple genes were differentially methylated; many of which are involved in reproductive processes or epigenetic modifications, suggesting a role of DNA methylation in later-life health outcomes. Additionally, several differentially methylated genes corresponded with gene expression changes identified in TCDD-exposed zebrafish testes, indicating a potential link between DNA methylation and gene expression. Ingenuity pathway analysis of WGBS and microarray data revealed genes involved in reproductive processes and development, RNA regulation, the cell cycle, and cellular morphology and development. We conclude that site-specific changes in DNA methylation of adult zebrafish testes occur in response to acute developmental TCDD exposure.
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Affiliation(s)
- Camille Akemann
- Department of Pharmacology, Wayne State University, Detroit, MI, United States
| | - Danielle N Meyer
- Department of Pharmacology, Wayne State University, Detroit, MI, United States.,Institute of Environmental Health Sciences, Wayne State University, Detroit, MI, United States
| | - Katherine Gurdziel
- Applied Genome Technology Center, School of Medicine, Wayne State University, Detroit, MI, United States
| | - Tracie R Baker
- Department of Pharmacology, Wayne State University, Detroit, MI, United States.,Institute of Environmental Health Sciences, Wayne State University, Detroit, MI, United States
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16
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Dang S, Ding D, Lu Y, Su Q, Lin T, Zhang X, Zhang H, Wang X, Tan H, Zhu Z, Li H. PM 2.5 exposure during pregnancy induces hypermethylation of estrogen receptor promoter region in rat uterus and declines offspring birth weights. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 243:851-861. [PMID: 30245447 DOI: 10.1016/j.envpol.2018.09.065] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/28/2018] [Accepted: 09/12/2018] [Indexed: 06/08/2023]
Abstract
Particulate matter 2.5 (PM2.5) exposures during pregnancy could lead to declined birth weight, intrauterine developmental restriction, and premature delivery, however, the underlying mechanisms are still not elucidated. There are few studies concerning the effects of PM2.5 exposure on maternal and child health in Xi'an (one of the cities with severe air pollution of PM2.5 in North China). Then, this study aimed to investigate the effect of PM2.5 exposure in Xi'an on the offspring birth weights and the possibly associated epigenetic mechanisms. We found the Low and High groups: the offspring with declined birth weights; the decreased mRNA and protein expression of the estrogen receptor (ERs) and eNOs in the uterus; the decreased endometria vascular diameter maximum (EVDM); the increased mRNA and protein expressions of the DNMT1 and 3b in the uterus; the elevated methylation levels of the CpG sites in the CpG island of ERα promoter region in the uterus. However, no differences were observed in the mRNA or protein expressions of ERβ and DNMT3a between the Clean and PM2.5 exposure groups, as well as endometriavascular density (EVD). Additionally, PM2.5 level was negatively correlated with the ERα protein expression, EVDM and offspring birth weight, as well as the methylation level of the CpG sites in the CpG island of ERα promoter region and the ERα protein expression in the uterus; whereas the ERα protein expression was positively correlated with the offspring birth weight, as well as PM2.5 level and the methylation level of the CpG sites in the CpG island of ERα promoter region in the uterus. Taken together, elevated methylation level of the CpG sites in the CpG island of ERα promoter region reduces ERα expression in the uterus, which could be one of the epigenetic mechanisms that pregnant PM2.5 exposure reduces the offspring birth weights.
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Affiliation(s)
- Shaokang Dang
- Division of Neonatology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China
| | - Ding Ding
- Division of Neonatology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China
| | - Yong Lu
- Department of Genetics, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, 710061, China
| | - Qian Su
- Division of Neonatology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China
| | - Tianwei Lin
- Key Laboratory of Shaanxi Province Biomedicine, College of Life Sciences, Northwest University, Xi'an, Shaanxi, 710061, China
| | - Xiaoxiao Zhang
- Key Laboratory of Shaanxi Province Biomedicine, College of Life Sciences, Northwest University, Xi'an, Shaanxi, 710061, China
| | - Huiping Zhang
- Division of Neonatology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China
| | - Xuebin Wang
- Department of Thermal Engineering, Energy and Power Engineering College of Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China
| | - Houzhang Tan
- Department of Thermal Engineering, Energy and Power Engineering College of Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China
| | - Zhongliang Zhu
- Key Laboratory of Shaanxi Province Biomedicine, College of Life Sciences, Northwest University, Xi'an, Shaanxi, 710061, China
| | - Hui Li
- Division of Neonatology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China.
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17
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Yang D, Yang X, Deng F, Guo X. Ambient Air Pollution and Biomarkers of Health Effect. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1017:59-102. [PMID: 29177959 DOI: 10.1007/978-981-10-5657-4_4] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Recently, the air pollution situation of our country is very serious along with the development of urbanization and industrialization. Studies indicate that the exposure of air pollution can cause a rise of incidence and mortality of many diseases, such as chronic obstructive pulmonary disease (COPD), asthma, myocardial infarction, and so on. However, there is now growing evidence showing that significant air pollution exposures are associated with early biomarkers in various systems of the body. In order to better prevent and control the damage effect of air pollution, this article summarizes comprehensively epidemiological studies about the bad effects on the biomarkers of respiratory system, cardiovascular system, and genetic and epigenetic system exposure to ambient air pollution.
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Affiliation(s)
- Di Yang
- Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, No. 38 Xueyuan Road, Beijing, China
| | - Xuan Yang
- Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, No. 38 Xueyuan Road, Beijing, China
| | - Furong Deng
- Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, No. 38 Xueyuan Road, Beijing, China.
| | - Xinbiao Guo
- Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, No. 38 Xueyuan Road, Beijing, China
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18
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Rota F, Conti A, Campo L, Favero C, Cantone L, Motta V, Polledri E, Mercadante R, Dieci G, Bollati V, Fustinoni S. Epigenetic and Transcriptional Modifications in Repetitive Elements in Petrol Station Workers Exposed to Benzene and MTBE. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:E735. [PMID: 29649143 PMCID: PMC5923777 DOI: 10.3390/ijerph15040735] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/30/2018] [Accepted: 04/08/2018] [Indexed: 12/19/2022]
Abstract
Benzene, a known human carcinogen, and methyl tert-butyl ether (MTBE), not classifiable as to its carcinogenicity, are fuel-related pollutants. This study investigated the effect of these chemicals on epigenetic and transcriptional alterations in DNA repetitive elements. In 89 petrol station workers and 90 non-occupationally exposed subjects the transcriptional activity of retrotransposons (LINE-1, Alu), the methylation on repeated-element DNA, and of H3K9 histone, were investigated in peripheral blood lymphocytes. Median work shift exposure to benzene and MTBE was 59 and 408 µg/m³ in petrol station workers, and 4 and 3.5 µg/m³, in controls. Urinary benzene (BEN-U), S-phenylmercapturic acid, and MTBE were significantly higher in workers than in controls, while trans,trans-muconic acid (tt-MA) was comparable between the two groups. Increased BEN-U was associated with increased Alu-Y and Alu-J expression; moreover, increased tt-MA was associated with increased Alu-Y and Alu-J and LINE-1 (L1)-5'UTR expression. Among repetitive element methylation, only L1-Pa5 was hypomethylated in petrol station workers compared to controls. While L1-Ta and Alu-YD6 methylation was not associated with benzene exposure, a negative association with urinary MTBE was observed. The methylation status of histone H3K9 was not associated with either benzene or MTBE exposure. Overall, these findings only partially support previous observations linking benzene exposure with global DNA hypomethylation.
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Affiliation(s)
- Federica Rota
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
| | - Anastasia Conti
- Department of Life Sciences, University of Parma, 43124 Parma, Italy.
- Present address: San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), 20132 Milan, Italy.
| | - Laura Campo
- Occupational Medicine Unit, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, 20122 Milan, Italy.
| | - Chiara Favero
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
| | - Laura Cantone
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
| | - Valeria Motta
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
| | - Elisa Polledri
- Occupational Medicine Unit, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, 20122 Milan, Italy.
| | - Rosa Mercadante
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
| | - Giorgio Dieci
- Department of Life Sciences, University of Parma, 43124 Parma, Italy.
| | - Valentina Bollati
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
- Occupational Medicine Unit, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, 20122 Milan, Italy.
| | - Silvia Fustinoni
- EPIGET, Epidemiology, Epigenetics and Toxicology Lab, Department of Clinical Sciences and Community Health, Università Degli Studi di Milano, via San Barnaba 8, 20122 Milan, Italy.
- Occupational Medicine Unit, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, 20122 Milan, Italy.
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19
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Martin EM, Fry RC. Environmental Influences on the Epigenome: Exposure- Associated DNA Methylation in Human Populations. Annu Rev Public Health 2018; 39:309-333. [PMID: 29328878 DOI: 10.1146/annurev-publhealth-040617-014629] [Citation(s) in RCA: 371] [Impact Index Per Article: 61.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
DNA methylation is the most well studied of the epigenetic regulators in relation to environmental exposures. To date, numerous studies have detailed the manner by which DNA methylation is influenced by the environment, resulting in altered global and gene-specific DNA methylation. These studies have focused on prenatal, early-life, and adult exposure scenarios. The present review summarizes currently available literature that demonstrates a relationship between DNA methylation and environmental exposures. It includes studies on aflatoxin B1, air pollution, arsenic, bisphenol A, cadmium, chromium, lead, mercury, polycyclic aromatic hydrocarbons, persistent organic pollutants, tobacco smoke, and nutritional factors. It also addresses gaps in the literature and future directions for research. These gaps include studies of mixtures, sexual dimorphisms with respect to environmentally associated methylation changes, tissue specificity, and temporal stability of the methylation marks.
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Affiliation(s)
- Elizabeth M Martin
- Department of Environmental Sciences and Engineering, and Curriculum in Toxicology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina 27599, USA; ,
| | - Rebecca C Fry
- Department of Environmental Sciences and Engineering, and Curriculum in Toxicology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina 27599, USA; ,
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20
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Zheng Y, Joyce BT, Liu L, Zhang Z, Kibbe WA, Zhang W, Hou L. Prediction of genome-wide DNA methylation in repetitive elements. Nucleic Acids Res 2017; 45:8697-8711. [PMID: 28911103 PMCID: PMC5587781 DOI: 10.1093/nar/gkx587] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 06/28/2017] [Indexed: 12/16/2022] Open
Abstract
DNA methylation in repetitive elements (RE) suppresses their mobility and maintains genomic stability, and decreases in it are frequently observed in tumor and/or surrogate tissues. Averaging methylation across RE in genome is widely used to quantify global methylation. However, methylation may vary in specific RE and play diverse roles in disease development, thus averaging methylation across RE may lose significant biological information. The ambiguous mapping of short reads by and high cost of current bisulfite sequencing platforms make them impractical for quantifying locus-specific RE methylation. Although microarray-based approaches (particularly Illumina's Infinium methylation arrays) provide cost-effective and robust genome-wide methylation quantification, the number of interrogated CpGs in RE remains limited. We report a random forest-based algorithm (and corresponding R package, REMP) that can accurately predict genome-wide locus-specific RE methylation based on Infinium array profiling data. We validated its prediction performance using alternative sequencing and microarray data. Testing its clinical utility with The Cancer Genome Atlas data demonstrated that our algorithm offers more comprehensively extended locus-specific RE methylation information that can be readily applied to large human studies in a cost-effective manner. Our work has the potential to improve our understanding of the role of global methylation in human diseases, especially cancer.
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Affiliation(s)
- Yinan Zheng
- Center for Population Epigenetics, Robert H. Lurie Comprehensive Cancer Center and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.,Division of Health and Biomedical Informatics, Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Brian T Joyce
- Center for Population Epigenetics, Robert H. Lurie Comprehensive Cancer Center and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Lei Liu
- Center for Population Epigenetics, Robert H. Lurie Comprehensive Cancer Center and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Zhou Zhang
- Center for Population Epigenetics, Robert H. Lurie Comprehensive Cancer Center and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.,Division of Health and Biomedical Informatics, Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Warren A Kibbe
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Rockville, MD 20850, USA
| | - Wei Zhang
- Center for Population Epigenetics, Robert H. Lurie Comprehensive Cancer Center and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Lifang Hou
- Center for Population Epigenetics, Robert H. Lurie Comprehensive Cancer Center and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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21
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Dose- and time- effect responses of DNA methylation and histone H3K9 acetylation changes induced by traffic-related air pollution. Sci Rep 2017; 7:43737. [PMID: 28256616 PMCID: PMC5335614 DOI: 10.1038/srep43737] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 01/30/2017] [Indexed: 11/08/2022] Open
Abstract
As an important risk factor of respiratory disorders, traffic-related air pollution (TRAP) has caused extensive concerns. Epigenetic change has been considered a link between TRAP and respiratory diseases. However, the exact effects of TRAP on epigenetic changes are still unclear. Here we investigated the dose- and time- effect responses of TRAP on DNA methylations and H3K9 acetylation (H3K9ac) in both blood and lung tissues of rats. The findings showed that every 1 μg/m3 increase of TRAP components were associated with changes in %5 mC (95% CI) in LINE-1, iNOS, p16CDKN2A, and APC ranging from −0.088% (−0.150, −0.026) to 0.102 (0.049, 0.154), as well as 0.276 (0.053, 0.498) to 0.475 (0.103, 0.848) ng/mg increase of H3K9ac. In addition, every 1 more day exposure at high level of TRAP (in tunnel) also significantly changed the levels of DNA methylation (ranging from −0.842% to 0.248%) and H3K9ac (16.033 and 15.718 ng/mg pro in PBMC and lung tissue, respectively) changes. Season and/or sex could interact with air pollutants in affecting DNA methylation and H3K9ac. The findings showed that TRAP exposure is dose- and time- dependently associated with the changes of DNA methylation and H3K9ac.
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Li J, Zhang X, He Z, Sun Q, Qin F, Huang Z, Zhang X, Sun X, Liu L, Chen L, Gao C, Wang S, Wang F, Li D, Zeng X, Deng Q, Wang Q, Zhang B, Tang H, Chen W, Xiao Y. MGMT hypomethylation is associated with DNA damage in workers exposed to low-dose benzene. Biomarkers 2017; 22:470-475. [DOI: 10.1080/1354750x.2016.1274335] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Jie Li
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Xinjie Zhang
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Zhini He
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Qing Sun
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Fei Qin
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Zhenlie Huang
- Guangdong Provincial Key Laboratory of Occupational Disease Prevention and Treatment, Guangdong Province Hospital for Occupational Disease Prevention and Treatment, Guangzhou, China
| | - Xiao Zhang
- Key Laboratory of Chemical Safety and Health, National Institute for Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xin Sun
- Key Laboratory of Chemical Safety and Health, National Institute for Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Linhua Liu
- Department of Toxicology, School of Public Health, Guangdong Medical University, Guangzhou, China
| | - Liping Chen
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Chen Gao
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Shan Wang
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Fangping Wang
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Daochuan Li
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Xiaowen Zeng
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Qifei Deng
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Qing Wang
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Bo Zhang
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Huanwen Tang
- Department of Toxicology, School of Public Health, Guangdong Medical University, Guangzhou, China
| | - Wen Chen
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Yongmei Xiao
- Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
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In vitro hydroquinone-induced instauration of histone bivalent mark on human retroelements (LINE-1) in HL60 cells. Toxicol In Vitro 2016; 40:1-10. [PMID: 27979589 DOI: 10.1016/j.tiv.2016.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 12/07/2016] [Accepted: 12/11/2016] [Indexed: 12/28/2022]
Abstract
Benzene is extensively used in industry despite its leukemogenic activity, representing a significant occupational hazard. We investigated if long-term treatment with low-doses hydroquinone (HQ), a benzene metabolite, might be sufficient to alter in vitro the epigenetic signature underlining LINE-1 sequences, a poorly explored step in health risks associated with benzene exposure. In HL-60 cell line, exploring the epigenetic events occurring in chromatin, we found the transient instauration of the distinctive signature combining the repressive H3Lys27 tri-methylation mark and the activating H3Lys4 tri-methylation mark (H3K27me3/H3K4me3), indicating a tendency toward a poised chromatin conformation. These alterations are lost in time after short-term treatments, while the long-term setting, performed using a concentration within the levels of total HQ in peripheral blood of benzene-exposed workers, showed a gradual increase in H3K4me3. We observed the absence of statistically significant variations in DNA methylation and expression levels of LINE-1, despite a decrease in protein levels of UHRF1, DNA methyl-transferases and histone methyl-transferases. In conclusion, in vitro treatment with low-dose HQ determined the instauration of a reversible poised state of chromatin in LINE-1 sequences, suggesting that prolonged exposure could cause persistent epigenetic alterations.
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24
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Desaulniers D, Cummings-Lorbetskie C, Li N, Xiao GH, Marro L, Khan N, Leingartner K. Sodium bisulfite pyrosequencing revealed that developmental exposure to environmental contaminant mixtures does not affect DNA methylation of DNA repeats in Sprague-Dawley rats. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2016; 80:32-52. [PMID: 27905861 DOI: 10.1080/15287394.2016.1231644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/29/2016] [Indexed: 06/06/2023]
Abstract
Hypomethylation of DNA repeats has been linked to diseases and cancer predisposition. Human studies suggest that higher blood concentrations of environmental contaminants (EC) correlate with levels of hypomethylation of DNA repeats in blood. The objective of this study was to examine the effect of in utero and/or lactational exposure to EC on the methylation of DNA repeats (LINE-1 and identifier element) in Sprague-Dawley rat pups at birth, at postnatal day (PND) 21, and in adulthood (PND78-86). From gestation day 0 to PND20, dams were exposed to a mixture "M" of polychlorinated biphenyls (PCB), pesticides, and methylmercury (MeHg), at 0.5 or 1 mg/kg/d (0.5M and M). At birth, some control (C) and M litters were cross-fostered to create the following in utero/postnatal exposure groups: C/C, M/C, C/M, M/M. Additional dams received 1.8 ng/kg/d of a mixture of aryl-hydrocarbon receptor (AhR) agonists (non-ortho-PCB, PC-dibenzodioxins, and PC-dibenzofurans) without or with 0.5M (0.5MAhR). Measurements of EC residue levels confirmed differences in their accumulation across treatments, age, and tissues. Although induction of hepatic detoxification enzyme activities (cytochrome P-450) demonstrated biological effects of treatments, the assessment of methylation in DNA repeats by sodium bisulfite pyrosequencing of liver, spleen, and thymus samples revealed no marked treatment-related effects but significant tissue- and age-related methylation differences. Further studies are required to determine whether absence of significant observable treatment effects on methylation of DNA repeats in the rat relate to tissue, strain, or species differences.
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Affiliation(s)
- Daniel Desaulniers
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Cathy Cummings-Lorbetskie
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Nanqin Li
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Gong-Hua Xiao
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Leonora Marro
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Nasrin Khan
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Karen Leingartner
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
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25
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Sierra MI, Valdés A, Fernández AF, Torrecillas R, Fraga MF. The effect of exposure to nanoparticles and nanomaterials on the mammalian epigenome. Int J Nanomedicine 2016; 11:6297-6306. [PMID: 27932878 PMCID: PMC5135284 DOI: 10.2147/ijn.s120104] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Human exposure to nanomaterials and nanoparticles is increasing rapidly, but their effects on human health are still largely unknown. Epigenetic modifications are attracting ever more interest as possible underlying molecular mechanisms of gene–environment interactions, highlighting them as potential molecular targets following exposure to nanomaterials and nanoparticles. Interestingly, recent research has identified changes in DNA methylation, histone post-translational modifications, and noncoding RNAs in mammalian cells exposed to nanomaterials and nanoparticles. However, the challenge for the future will be to determine the molecular pathways driving these epigenetic alterations, the possible functional consequences, and the potential effects on health.
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Affiliation(s)
- M I Sierra
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA), Hospital Universitario Central de Asturias (HUCA), Universidad de Oviedo, Oviedo
| | - A Valdés
- Nanomaterials and Nanotechnology Research Center (CINN-CSIC), Universidad de Oviedo-Principado de Asturias, El Entrego, Spain
| | - A F Fernández
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA), Hospital Universitario Central de Asturias (HUCA), Universidad de Oviedo, Oviedo
| | - R Torrecillas
- Nanomaterials and Nanotechnology Research Center (CINN-CSIC), Universidad de Oviedo-Principado de Asturias, El Entrego, Spain
| | - M F Fraga
- Nanomaterials and Nanotechnology Research Center (CINN-CSIC), Universidad de Oviedo-Principado de Asturias, El Entrego, Spain
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26
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Prior S, Miousse IR, Nzabarushimana E, Pathak R, Skinner C, Kutanzi KR, Allen AR, Raber J, Tackett AJ, Hauer-Jensen M, Nelson GA, Koturbash I. Densely ionizing radiation affects DNA methylation of selective LINE-1 elements. ENVIRONMENTAL RESEARCH 2016; 150:470-481. [PMID: 27419368 PMCID: PMC5003736 DOI: 10.1016/j.envres.2016.06.043] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 06/15/2016] [Accepted: 06/27/2016] [Indexed: 05/26/2023]
Abstract
Long Interspersed Nucleotide Element 1 (LINE-1) retrotransposons are heavily methylated and are the most abundant transposable elements in mammalian genomes. Here, we investigated the differential DNA methylation within the LINE-1 under normal conditions and in response to environmentally relevant doses of sparsely and densely ionizing radiation. We demonstrate that DNA methylation of LINE-1 elements in the lungs of C57BL6 mice is dependent on their evolutionary age, where the elder age of the element is associated with the lower extent of DNA methylation. Exposure to 5-aza-2'-deoxycytidine and methionine-deficient diet affected DNA methylation of selective LINE-1 elements in an age- and promoter type-dependent manner. Exposure to densely IR, but not sparsely IR, resulted in DNA hypermethylation of older LINE-1 elements, while the DNA methylation of evolutionary younger elements remained mostly unchanged. We also demonstrate that exposure to densely IR increased mRNA and protein levels of LINE-1 via the loss of the histone H3K9 dimethylation and an increase in the H3K4 trimethylation at the LINE-1 5'-untranslated region, independently of DNA methylation. Our findings suggest that DNA methylation is important for regulation of LINE-1 expression under normal conditions, but histone modifications may dictate the transcriptional activity of LINE-1 in response to exposure to densely IR.
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Affiliation(s)
- Sara Prior
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Isabelle R Miousse
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Etienne Nzabarushimana
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA; Department of Bioinformatics, School of Informatics and Computing, Indiana University, Bloomington, IN 47405, USA
| | - Rupak Pathak
- Division of Radiation Health, Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Charles Skinner
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Kristy R Kutanzi
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Antiño R Allen
- Division of Radiation Health, Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Jacob Raber
- Departments of Behavioral Neuroscience, Neurology, and Radiation Medicine, Division of Neuroscience, ONPRC, Oregon Health & Science University, Portland, OR 97239, USA
| | - Alan J Tackett
- Department of Biochemistry, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Martin Hauer-Jensen
- Division of Radiation Health, Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Gregory A Nelson
- Department of Basic Sciences, Division of Radiation Research, Loma Linda University, Loma Linda, CA 92350, USA
| | - Igor Koturbash
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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27
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Armstrong DA, Green BB, Blair BA, Guerin DJ, Litzky JF, Chavan NR, Pearson KJ, Marsit CJ. Maternal smoking during pregnancy is associated with mitochondrial DNA methylation. ENVIRONMENTAL EPIGENETICS 2016; 2:dvw020. [PMID: 28979800 PMCID: PMC5624552 DOI: 10.1093/eep/dvw020] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Maternal smoking during pregnancy (MSDP) has detrimental effects on fetal development and on the health of the offspring into adulthood. Energy homeostasis through ATP production via the mitochondria (mt) plays a key role during pregnancy. This study aimed to determine if MSDP resulted in differences in DNA methylation to the placental mitochondrial chromosome at the transcription and replication control region, the D-Loop, and if these differences were also present in an alternate neonatal tissue (foreskin) in an independent birth cohort. We investigated mtDNA methylation by bisulfite-pyrosequencing in two sections of the D-Loop control region and in long interspersed nuclear element-1 (LINE-1) genomic sequences in placenta from 96 mother-newborn pairs that were enrolled in a Rhode Island birth cohort along with foreskin samples from 62 infants from a Kentucky birth cohort. In both placenta and foreskin, mtDNA methylation in the light chain D-Loop region 1 was positively associated with MSDP in placenta (difference+2.73%) (P=0.001) and foreskin (difference+1.22%) (P=0.08). Additionally, in foreskin, a second segment of the D-Loop-heavy chain region 1 showed a small but significant change in methylation with MSDP (+0.4%, P=0.04). No methylation changes were noted in either tissue at the LINE-1 repetitive element. We identified a similar pattern of epigenetic effect to mitochondria arising in cells from different primordial lineages and in different populations, associated with MSDP. These robust and consistent results build evidence that MSDP may impact mt D-Loop methylation, as one mechanism through which this exposure affects newborn health.
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Affiliation(s)
- David A. Armstrong
- Department of Pharmacology and Toxicology
- Department of Pulmonary Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | | | | | | | | | - Niraj R. Chavan
- Department of Obstetrics and Gynecology, Maternal Fetal Medicine
| | - Kevin J. Pearson
- Department of Obstetrics and Gynecology, Maternal Fetal Medicine
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Carmen J. Marsit
- Department of Pharmacology and Toxicology
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA
- *Correspondence address. Department of Environmental Health, Rollins School of Public Health, Emory University, 1518 Clifton Road, Atlanta, GA 30322, USA; Tel: +404-712-8912; Fax: 404-727-8744; E-mail: Marsit:
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28
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Goodrich JM, Reddy P, Naidoo RN, Asharam K, Batterman S, Dolinoy DC. Prenatal exposures and DNA methylation in newborns: a pilot study in Durban, South Africa. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2016; 18:908-17. [PMID: 27359112 PMCID: PMC4945397 DOI: 10.1039/c6em00074f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The in utero environment has the potential to influence epigenetic programming and subsequently the health of offspring. Even though pregnant women living in urban Africa are exposed to multiple chemicals and infectious agents that may impact their developing children, the neonatal epigenome has not been studied in these regions. We assessed whether prenatal exposures to air pollution and maternal human immunodeficiency virus (HIV) are associated with changes to DNA methylation throughout the epigenome using a pilot sample from the Mother and Child Environmental (MACE) birth cohort, of which 36% of the mothers are HIV positive. Families living in a high air pollution region (south Durban, n = 11) and a low air pollution region (north Durban, n = 11) with comparable socioeconomic characteristics were selected for analysis. DNA methylation was quantified in cord blood plasma DNA at >430 000 CpG sites using the Infinium HumanMethylation450 BeadChip. Sites associated with living in south Durban or maternal HIV infection (p < 0.001) were more likely to be hypomethylated and located in CpG islands. Top differentially methylated sites by region of Durban were enriched in pathways related to xenobiotic metabolism, oxygen and gas transport, and sensory perception of chemical stimuli when performing gene set enrichment testing with LRpath. Differentially methylated sites by maternal HIV status were enriched in cytochrome P450s, pathways involved in detection of chemical stimuli, metabolic processes, and viral regulation and processing. Given the small sample size of the study, future work examining the impact of prenatal exposures to air pollution, maternal infection, and antiviral treatment on the epigenome and downstream health implications is merited in Sub-Saharan African populations.
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Affiliation(s)
- Jaclyn M Goodrich
- Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109, USA.
| | - Poovendhree Reddy
- Department of Community Health Studies, Durban University of Technology, Durban, South Africa
| | - Rajen N Naidoo
- Discipline of Occupational and Environmental Health, School of Nursing and Public Health, University of KwaZulu-Natal, Durban, South Africa
| | - Kareshma Asharam
- Discipline of Occupational and Environmental Health, School of Nursing and Public Health, University of KwaZulu-Natal, Durban, South Africa
| | - Stuart Batterman
- Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109, USA.
| | - Dana C Dolinoy
- Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109, USA. and Department of Nutritional Sciences, University of Michigan, Ann Arbor, MI, USA
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29
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Huen K, Calafat AM, Bradman A, Yousefi P, Eskenazi B, Holland N. Maternal phthalate exposure during pregnancy is associated with DNA methylation of LINE-1 and Alu repetitive elements in Mexican-American children. ENVIRONMENTAL RESEARCH 2016; 148:55-62. [PMID: 27019040 PMCID: PMC4874877 DOI: 10.1016/j.envres.2016.03.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 02/24/2016] [Accepted: 03/18/2016] [Indexed: 05/21/2023]
Abstract
Phthalates are frequently used in personal care products and plasticizers and phthalate exposure is ubiquitous in the US population. Exposure to phthalates during critical periods in utero has been associated with a variety of adverse health outcomes but the biological mechanisms linking these exposures with disease are not well characterized. In this study, we examined the relationship of in utero phthalate exposure with repetitive element DNA methylation, an epigenetic marker of genome instability, in children from the longitudinal birth cohort CHAMACOS. Methylation of Alu and long interspersed nucleotide elements (LINE-1) was determined using pyrosequencing of bisulfite-treated DNA isolated from whole blood samples collected from newborns and 9 year old children (n=355). Concentrations of eleven phthalate metabolites were measured in urine collected from pregnant mothers at 13 and 26 weeks gestation. We found a consistent inverse association between prenatal concentrations of monoethyl phthalate, the most frequently detected urinary metabolite, with cord blood methylation of Alu repeats (β(95%CI): -0.14 (-0.28,0.00) and -0.16 (-0.31, -0.02)) for early and late pregnancy, respectively, and a similar but weaker association with LINE-1 methylation. Additionally, increases in urinary concentrations of di-(2-ethylhexyl) phthalate metabolites during late pregnancy were associated with lower levels of methylation of Alu repeats in 9 year old blood (significant p-values ranged from 0.003 to 0.03). Our findings suggest that prenatal exposure to some phthalates may influence differences in repetitive element methylation, highlighting epigenetics as a plausible biological mechanism through which phthalates may affect health.
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Affiliation(s)
- Karen Huen
- Center for Children's Environmental Health, School of Public Health, University of California, Berkeley, 1995 University Avenue Suite 265, Berkeley, CA 94720, USA.
| | - Antonia M Calafat
- Centers for Disease Control and Prevention, 4770 Buford Hwy, MS F17, Atlanta, GA 30341, USA.
| | - Asa Bradman
- Center for Children's Environmental Health, School of Public Health, University of California, Berkeley, 1995 University Avenue Suite 265, Berkeley, CA 94720, USA.
| | - Paul Yousefi
- Center for Children's Environmental Health, School of Public Health, University of California, Berkeley, 1995 University Avenue Suite 265, Berkeley, CA 94720, USA.
| | - Brenda Eskenazi
- Center for Children's Environmental Health, School of Public Health, University of California, Berkeley, 1995 University Avenue Suite 265, Berkeley, CA 94720, USA.
| | - Nina Holland
- Center for Children's Environmental Health, School of Public Health, University of California, Berkeley, 1995 University Avenue Suite 265, Berkeley, CA 94720, USA.
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30
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DNA methylation of LINE-1 and Alu repetitive elements in relation to sex hormones and pubertal timing in Mexican-American children. Pediatr Res 2016; 79:855-62. [PMID: 26882368 PMCID: PMC4899098 DOI: 10.1038/pr.2016.31] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/09/2015] [Indexed: 12/21/2022]
Abstract
BACKGROUND The molecular mechanisms linking environmental exposures to earlier pubertal development are not well characterized. Epigenetics may play an important role, but data on the relationship between epigenetic marks and puberty, particularly in humans, is limited. METHODS We used pyrosequencing to measure Alu and long interspersed nucleotide elements (LINE-1) methylation in DNA isolated from whole blood samples collected from newborns and 9-y-old children (n = 266). Tanner staging was completed six times between ages 9 and 12 y to determine pubertal status, and hormone levels were measured in 12-y-old boys. RESULTS Among girls, we observed a suggestive trend of increased odds of breast and pubic hair development with higher Alu and LINE-1 methylation in 9-y-old blood, respectively. The strongest association identified was an inverse association of LINE-1 methylation in 9-y-old girls with odds of experiencing menarche by age 12 (OR (95% CI): 0.63 (0.46, 0.87); P = 0.005). We observed a consistent inverse relationship for Alu and LINE-1 methylation at 9 y with luteinizing hormone (LH), testosterone and follicle-stimulating hormone levels in boys but it was only significant between LINE-1 and LH. CONCLUSION DNA methylation of Alu and LINE-1 may be involved in puberty initiation and development. This relationship should be confirmed in future studies.
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31
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Conti A, Rota F, Ragni E, Favero C, Motta V, Lazzari L, Bollati V, Fustinoni S, Dieci G. Hydroquinone induces DNA hypomethylation-independent overexpression of retroelements in human leukemia and hematopoietic stem cells. Biochem Biophys Res Commun 2016; 474:691-695. [DOI: 10.1016/j.bbrc.2016.05.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 05/02/2016] [Indexed: 10/21/2022]
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32
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Byun HM, Colicino E, Trevisi L, Fan T, Christiani DC, Baccarelli AA. Effects of Air Pollution and Blood Mitochondrial DNA Methylation on Markers of Heart Rate Variability. J Am Heart Assoc 2016; 5:JAHA.116.003218. [PMID: 27107129 PMCID: PMC4843532 DOI: 10.1161/jaha.116.003218] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Background The mitochondrion is the primary target of oxidative stress in response to exogenous environments. Mitochondrial DNA (mtDNA) is independent from nuclear DNA and uses separate epigenetic machinery to regulate mtDNA methylation. The mtDNA damage induced by oxidative stress can cause mitochondrial dysfunction and is implicated in human diseases; however, mtDNA methylation has been largely overlooked in environmental studies relating to human disease. The purpose of this study was to examine the association between exposure to fine metal‐rich particulates (particulate matter <2.5 µm in diameter [PM2.5]) from welding in a boilermaker union and blood mtDNA methylation in relation to heart rate variability. Methods and Results Forty‐eight healthy men were recruited on multiple sampling cycles at the Boilermaker Union Local 29, located in Quincy, Massachusetts. We measured personal PM2.5 in the background ambient environment. We measured blood mtDNA methylation in the mtDNA promoter (D‐loop) and genes essential for ATP synthesis (MT‐TF and MT‐RNR1) by bisulfite pyrosequencing. All analyses were adjusted for demographics, type of job, season, welding‐work day, and mtDNA methylation experimental batch effect. The participants’ PM2.5 exposure was significantly higher after a welding‐work day (mean 0.38 mg/m3) than the background personal level (mean 0.15 mg/m3, P<0.001). Blood mtDNA methylation in the D‐loop promoter was associated with PM2.5 levels (β=−0.99%, SE=0.41, P=0.02). MT‐TF and MT‐RNR1 methylation was not associated with PM2.5 exposure (β=0.10%, SE=0.45, P=0.82). Interaction of PM2.5 exposure levels and D‐loop promoter methylation was significantly associated with markers of heart rate variability. Conclusions Blood mtDNA methylation levels were negatively associated with PM2.5 exposure and modified the adverse relationships between PM2.5 exposure and heart rate variability outcomes.
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Affiliation(s)
- Hyang-Min Byun
- Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Elena Colicino
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA
| | - Letizia Trevisi
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA
| | - Tianteng Fan
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA
| | - David C Christiani
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA
| | - Andrea A Baccarelli
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA
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Tabish AM, Baccarelli AA, Godderis L, Barrow TM, Hoet P, Byun HM. Assessment of Changes in Global DNA Methylation Levels by Pyrosequencing® of Repetitive Elements. Methods Mol Biol 2016; 1315:201-7. [PMID: 26103901 DOI: 10.1007/978-1-4939-2715-9_15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Transposable elements (TE) comprise half of the human genome. LINE-1 and ALU are the most common TE, and they have been used to assess changes in the DNA methylation of repetitive elements in response to intrinsic and extrinsic cellular events. Pyrosequencing(®) is a real-time sequencing technology that enables quantitative assessment of TE methylation at single-base resolution. In Pyrosequencing, a region of interest is first amplified from bisulfite-converted DNA by polymerase chain reaction (PCR), before PCR amplicons are rendered single stranded and annealed with the Pyrosequencing primer prior to sequencing. In this chapter, we provide an overview of the analysis of repetitive element DNA methylation by bisulfite Pyrosequencing, and we describe a protocol that can be used for such purposes.
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Affiliation(s)
- Ali M Tabish
- Department of Public Health and Primary Care, Katholieke Universiteit Leuven, Kapucijnenvoer 35 Blok D, Leuven, B-3000, Belgium,
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Sanchez-Guerra M, Zheng Y, Osorio-Yanez C, Zhong J, Chervona Y, Wang S, Chang D, McCracken JP, Díaz A, Bertazzi PA, Koutrakis P, Kang CM, Zhang X, Zhang W, Byun HM, Schwartz J, Hou L, Baccarelli AA. Effects of particulate matter exposure on blood 5-hydroxymethylation: results from the Beijing truck driver air pollution study. Epigenetics 2016; 10:633-42. [PMID: 25970091 PMCID: PMC4623004 DOI: 10.1080/15592294.2015.1050174] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Previous studies have reported epigenetic changes induced by environmental exposures. However, previous investigations did not distinguish 5-methylcytosine (5mC) from a similar oxidative form with opposite functions, 5-hydroxymethylcytosine (5hmC). Here, we measured blood DNA global 5mC and 5hmC by ELISA and used adjusted mixed-effects regression models to evaluate the effects of ambient PM10 and personal PM2.5 and its elemental components—black carbon (BC), aluminum (Al), calcium (Ca), potassium (K), iron (Fe), sulfur (S), silicon (Si), titanium (Ti), and zinc (Zn)—on blood global 5mC and 5hmC levels. The study was conducted in 60 truck drivers and 60 office workers in Beijing, China from The Beijing Truck Driver Air Pollution Study at 2 exams separated by one to 2 weeks. Blood 5hmC level (0.08%) was ∼83-fold lower than 5mC (6.61%). An inter-quartile range (IQR) increase in same-day PM10 was associated with increases in 5hmC of 26.1% in office workers (P = 0.004), 20.2% in truck drivers (P = 0.014), and 21.9% in all participants combined (P < 0.001). PM10 effects on 5hmC were increasingly stronger when averaged over 4, 7, and 14 d preceding assessment (up to 132.6% for the 14-d average in all participants, P < 0.001). PM10 effects were also significant after controlling for multiple testing (family-wise error rate; FWER < 0.05). 5hmC was not correlated with personal measures of PM2.5 and elemental components (FWER > 0.05). 5mC showed no correlations with PM10, PM2.5, and elemental components measures (FWER > 0.05). Our study suggests that exposure to ambient PM10 affects 5hmC over time, but not 5mC. This finding demonstrates the need to differentiate 5hmC and 5mC in environmental studies of DNA methylation.
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Key Words
- 10 μm
- 2.5 μm
- 5-hydroxymethylcytosine
- 5-methylcytosine
- 5hmC, 5-hydroxymethylcytosine
- 5mC, 5-methylcytosine
- Al, aluminum
- BC, black carbon
- BMI, body mass index
- CI, confidence interval
- Ca, calcium
- DNA methylation
- ELISA, enzyme-linked immunosorbent assay
- Epigenetics
- FWER, family-wise error rate
- Fe, iron
- HPLC, high-performance liquid chromatography
- K, potassium
- PM, particulate matter
- PM10, particulate matter ≤
- PM2.5, particulate matter ≤
- Particulate Matter
- S, sulfur
- Si: silicon
- TET, ten-eleven translocation enzymes
- Ti, titanium and Zn: zinc.
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Affiliation(s)
- Marco Sanchez-Guerra
- a Department of Environmental Health; Harvard T.H. Chan School of Public Health ; Boston , MA , USA
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Miousse IR, Chalbot MCG, Pathak R, Lu X, Nzabarushimana E, Krager K, Aykin-Burns N, Hauer-Jensen M, Demokritou P, Kavouras IG, Koturbash I. In Vitro Toxicity and Epigenotoxicity of Different Types of Ambient Particulate Matter. Toxicol Sci 2015; 148:473-87. [PMID: 26342214 PMCID: PMC5009441 DOI: 10.1093/toxsci/kfv200] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Exposure to ambient particulate matter (PM) has been associated with adverse health effects, including pulmonary and cardiovascular disease. Studies indicate that ambient PM originated from different sources may cause distinct biological effects. In this study, we sought to investigate the potential of various types of PM to cause epigenetic alterations in the in vitro system. RAW264.7 murine macrophages were exposed for 24 and 72 h to 5- and 50-μg/ml doses of the water soluble extract of 6 types of PM: soil dust, road dust, agricultural dust, traffic exhausts, biomass burning, and pollen, collected in January-April of 2014 in the area of Little Rock, Arkansas. Cytotoxicity, oxidative potential, epigenetic endpoints, and chromosomal aberrations were addressed. Exposure to 6 types of PM resulted in induction of cytotoxicity and oxidative stress in a type-, time-, and dose-dependent manner. Epigenetic alterations were characterized by type-, time-, and dose-dependent decreases of DNA methylation/demethylation machinery, increased DNA methyltransferases enzymatic activity and protein levels, and transcriptional activation and subsequent silencing of transposable elements LINE-1, SINE B1/B2. The most pronounced changes were observed after exposure to soil dust that were also characterized by hypomethylation and reactivation of satellite DNA and structural chromosomal aberrations in the exposed cells. The results of our study indicate that the water-soluble fractions of the various types of PM have differential potential to target the cellular epigenome.
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Affiliation(s)
- Isabelle R Miousse
- *Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health and
| | - Marie-Cecile G Chalbot
- *Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health and
| | - Rupak Pathak
- Division of Radiation Health, Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Xiaoyan Lu
- Center for Nanotechnology and Nanotoxicology, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts; and
| | - Etienne Nzabarushimana
- *Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health and Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Kimberly Krager
- Division of Radiation Health, Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Nukhet Aykin-Burns
- Division of Radiation Health, Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Martin Hauer-Jensen
- Division of Radiation Health, Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Philip Demokritou
- Center for Nanotechnology and Nanotoxicology, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts; and
| | - Ilias G Kavouras
- *Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health and
| | - Igor Koturbash
- *Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health and
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The Fine LINE: Methylation Drawing the Cancer Landscape. BIOMED RESEARCH INTERNATIONAL 2015; 2015:131547. [PMID: 26448926 PMCID: PMC4584040 DOI: 10.1155/2015/131547] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 11/17/2014] [Accepted: 11/25/2014] [Indexed: 01/08/2023]
Abstract
LINE-1 (L1) is the most abundant mammalian transposable element that comprises nearly 20% of the genome, and nearly half of the mammalian genome has stemmed from L1-mediated mobilization. Expression and retrotransposition of L1 are suppressed by complex mechanisms, where the key role belongs to DNA methylation. Alterations in L1 methylation may lead to aberrant expression of L1 and have been described in numerous diseases. Accumulating evidence clearly indicates that loss of global DNA methylation observed in cancer development and progression is tightly associated with hypomethylation of L1 elements. Significant progress achieved in the last several years suggests that such parameters as L1 methylation status can be potentially utilized as clinical biomarkers for determination of the disease stage and in predicting the disease-free survival in cancer patients. In this paper, we summarize the current knowledge on L1 methylation, with specific emphasis given to success and challenges on the way of introduction of L1 into clinical practice.
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Environmental Impact on DNA Methylation in the Germline: State of the Art and Gaps of Knowledge. BIOMED RESEARCH INTERNATIONAL 2015; 2015:123484. [PMID: 26339587 PMCID: PMC4538313 DOI: 10.1155/2015/123484] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 05/03/2015] [Indexed: 12/19/2022]
Abstract
The epigenome consists of chemical changes in DNA and chromatin that without modifying the DNA sequence modulate gene expression and cellular phenotype. The epigenome is highly plastic and reacts to changing external conditions with modifications that can be inherited to daughter cells and across generations. Whereas this innate plasticity allows for adaptation to a changing environment, it also implies the potential of epigenetic derailment leading to so-called epimutations. DNA methylation is the most studied epigenetic mark. DNA methylation changes have been associated with cancer, infertility, cardiovascular, respiratory, metabolic, immunologic, and neurodegenerative pathologies. Experiments in rodents demonstrate that exposure to a variety of chemical stressors, occurring during the prenatal or the adult life, may induce DNA methylation changes in germ cells, which may be transmitted across generations with phenotypic consequences. An increasing number of human biomonitoring studies show environmentally related DNA methylation changes mainly in blood leukocytes, whereas very few data have been so far collected on possible epigenetic changes induced in the germline, even by the analysis of easily accessible sperm. In this paper, we review the state of the art on factors impinging on DNA methylation in the germline, highlight gaps of knowledge, and propose priorities for future studies.
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CYP2E1 epigenetic regulation in chronic, low-level toluene exposure: Relationship with oxidative stress and smoking habit. Toxicol Appl Pharmacol 2015; 286:207-15. [DOI: 10.1016/j.taap.2015.04.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Revised: 04/08/2015] [Accepted: 04/29/2015] [Indexed: 12/31/2022]
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Miousse IR, Chalbot MCG, Lumen A, Ferguson A, Kavouras IG, Koturbash I. Response of transposable elements to environmental stressors. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2015; 765:19-39. [PMID: 26281766 PMCID: PMC4544780 DOI: 10.1016/j.mrrev.2015.05.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 05/27/2015] [Accepted: 05/28/2015] [Indexed: 12/21/2022]
Abstract
Transposable elements (TEs) comprise a group of repetitive sequences that bring positive, negative, as well as neutral effects to the host organism. Earlier considered as "junk DNA," TEs are now well-accepted driving forces of evolution and critical regulators of the expression of genetic information. Their activity is regulated by epigenetic mechanisms, including methylation of DNA and histone modifications. The loss of epigenetic control over TEs, exhibited as loss of DNA methylation and decondensation of the chromatin structure, may result in TEs reactivation, initiation of their insertional mutagenesis (retrotransposition) and has been reported in numerous human diseases, including cancer. Accumulating evidence suggests that these alterations are not the simple consequences of the disease, but often may drive the pathogenesis, as they can be detected early during disease development. Knowledge derived from the in vitro, in vivo, and epidemiological studies, clearly demonstrates that exposure to ubiquitous environmental stressors, many of which are carcinogens or suspected carcinogens, are capable of causing alterations in methylation and expression of TEs and initiate retrotransposition events. Evidence summarized in this review suggests that TEs are the sensitive endpoints for detection of effects caused by such environmental stressors, as ionizing radiation (terrestrial, space, and UV-radiation), air pollution (including particulate matter [PM]-derived and gaseous), persistent organic pollutants, and metals. Furthermore, the significance of these effects is characterized by their early appearance, persistence and presence in both, target organs and peripheral blood. Altogether, these findings suggest that TEs may potentially be introduced into safety and risk assessment and serve as biomarkers of exposure to environmental stressors. Furthermore, TEs also show significant potential to become invaluable surrogate biomarkers in clinic and possible targets for therapeutic modalities for disease treatment and prevention.
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Affiliation(s)
- Isabelle R Miousse
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
| | - Marie-Cecile G Chalbot
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
| | - Annie Lumen
- Division of Biochemical Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA.
| | - Alesia Ferguson
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
| | - Ilias G Kavouras
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
| | - Igor Koturbash
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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40
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Goodrich JM, Sánchez BN, Dolinoy DC, Zhang Z, Hernández-Ávila M, Hu H, Peterson KE, Téllez-Rojo MM. Quality control and statistical modeling for environmental epigenetics: a study on in utero lead exposure and DNA methylation at birth. Epigenetics 2015; 10:19-30. [PMID: 25580720 DOI: 10.4161/15592294.2014.989077] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
DNA methylation data assayed using pyrosequencing techniques are increasingly being used in human cohort studies to investigate associations between epigenetic modifications at candidate genes and exposures to environmental toxicants and to examine environmentally-induced epigenetic alterations as a mechanism underlying observed toxicant-health outcome associations. For instance, in utero lead (Pb) exposure is a neurodevelopmental toxicant of global concern that has also been linked to altered growth in human epidemiological cohorts; a potential mechanism of this association is through alteration of DNA methylation (e.g., at growth-related genes). However, because the associations between toxicants and DNA methylation might be weak, using appropriate quality control and statistical methods is important to increase reliability and power of such studies. Using a simulation study, we compared potential approaches to estimate toxicant-DNA methylation associations that varied by how methylation data were analyzed (repeated measures vs. averaging all CpG sites) and by method to adjust for batch effects (batch controls vs. random effects). We demonstrate that correcting for batch effects using plate controls yields unbiased associations, and that explicitly modeling the CpG site-specific variances and correlations among CpG sites increases statistical power. Using the recommended approaches, we examined the association between DNA methylation (in LINE-1 and growth related genes IGF2, H19 and HSD11B2) and 3 biomarkers of Pb exposure (Pb concentrations in umbilical cord blood, maternal tibia, and maternal patella), among mother-infant pairs of the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) cohort (n = 247). Those with 10 μg/g higher patella Pb had, on average, 0.61% higher IGF2 methylation (P = 0.05). Sex-specific trends between Pb and DNA methylation (P < 0.1) were observed among girls including a 0.23% increase in HSD11B2 methylation with 10 μg/g higher patella Pb.
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Key Words
- ANOVA, analysis of variance
- DMR, differentially methylated region
- DNA methylation
- ELEMENT, early life exposures in Mexico to environmental toxicants
- GEE, generalized estimating equation
- GLM, general linear model
- H19, H19, imprinted maternally expressed transcript (non-protein coding)
- HSD11B2, hydroxysteroid (11-β) dehydrogenase 2
- IGF2, insulin-like growth factor 2
- K-XRF, K X-ray fluorescence
- LINE-1, long interspersed element-1
- OLS, ordinary linear regression
- PCR, polymerase chain reaction
- Pb, lead
- environmental exposure
- lead
- pyrosequencing
- quality control
- statistical methods
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Affiliation(s)
- Jaclyn M Goodrich
- a Department of Environmental Health Sciences ; University of Michigan School of Public Health ; Ann Arbor , MI USA
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Byun HM, Barrow TM. Analysis of pollutant-induced changes in mitochondrial DNA methylation. Methods Mol Biol 2015; 1265:271-83. [PMID: 25634281 DOI: 10.1007/978-1-4939-2288-8_19] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
There is increasing evidence that exposure to air pollutants is associated with human disease and may act through epigenetic modification of the nuclear genome, but there have been few publications describing their impact upon the mitochondrial genome. Mitochondrial DNA may be more susceptible to pollutant-induced changes via increased oxidative stress in the cell, and therefore this field of research is of growing interest. Many techniques employed to study DNA methylation of the nuclear genome are also applicable to mitochondrial epigenetic studies. In this chapter, we describe a protocol for the isolation of mitochondrial DNA from peripheral blood samples and the analysis of 5-methylcytosine content by bisulfite pyrosequencing.
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Affiliation(s)
- Hyang-Min Byun
- Laboratory of Environmental Epigenetics, Exposure Epidemiology and Risk Program, Harvard School of Public Health, Boston, MA, USA,
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Lee J, Kim YJ, Mun S, Kim HS, Han K. Identification of human-specific AluS elements through comparative genomics. Gene 2014; 555:208-16. [PMID: 25447892 DOI: 10.1016/j.gene.2014.11.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 11/03/2014] [Accepted: 11/05/2014] [Indexed: 01/08/2023]
Abstract
Mobile elements are responsible for ~45% of the human genome. Among them is the Alu element, accounting for 10% of the human genome (>1.1million copies). Several studies of Alu elements have reported that they are frequently involved in human genetic diseases and genomic rearrangements. In this study, we investigated the AluS subfamily, which is a relatively old Alu subfamily and has the highest copy number in primate genomes. Previously, a set of 263 human-specific AluS insertions was identified in the human genome. To validate these, we compared each of the human-specific AluS loci with its pre-insertion site in other primate genomes, including chimpanzee, gorilla, and orangutan. We obtained 24 putative human-specific AluS candidates via the in silico analysis and manual inspection, and then tried to verify them using PCR amplification and DNA sequencing. Through the PCR product sequencing, we were able to detect two instances of near-parallel Alu insertions in nearby sites that led to computational false negatives. Finally, we computationally and experimentally verified 23 human-specific AluS elements. We reported three alternative Alu insertion events, which are accompanied by filler DNA and/or Alu retrotransposition mediated-deletion. Bisulfite sequencing was carried out to examine DNA methylation levels of human-specific AluS elements. The results showed that fixed AluS elements are hypermethylated compared with polymorphic elements, indicating a possible relation between DNA methylation and Alu fixation in the human genome.
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Affiliation(s)
- Jae Lee
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 330-714, Republic of Korea
| | - Yun-Ji Kim
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 330-714, Republic of Korea; DKU-Theragen Institute for NGS Analysis (DTiNa), Cheonan 330-714, Republic of Korea
| | - Seyoung Mun
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 330-714, Republic of Korea; DKU-Theragen Institute for NGS Analysis (DTiNa), Cheonan 330-714, Republic of Korea
| | - Heui-Soo Kim
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735, Republic of Korea
| | - Kyudong Han
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 330-714, Republic of Korea; DKU-Theragen Institute for NGS Analysis (DTiNa), Cheonan 330-714, Republic of Korea.
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Vilahur N, Bustamante M, Byun HM, Fernandez MF, Santa Marina L, Basterrechea M, Ballester F, Murcia M, Tardón A, Fernández-Somoano A, Estivill X, Olea N, Sunyer J, Baccarelli AA. Prenatal exposure to mixtures of xenoestrogens and repetitive element DNA methylation changes in human placenta. ENVIRONMENT INTERNATIONAL 2014; 71:81-7. [PMID: 24980756 PMCID: PMC4122792 DOI: 10.1016/j.envint.2014.06.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 05/07/2014] [Accepted: 06/05/2014] [Indexed: 05/18/2023]
Abstract
BACKGROUND Prenatal exposure to endocrine disrupting compounds (EDCs) has previously shown to alter epigenetic marks. OBJECTIVES In this work we explore whether prenatal exposure to mixtures of xenoestrogens has the potential to alter the placenta epigenome, by studying DNA methylation in retrotransposons as a surrogate of global DNA methylation. METHODS The biomarker total effective xenoestrogen burden (TEXB) was measured in 192 placentas from participants in the longitudinal INMA Project. DNA methylation was quantitatively assessed by bisulfite pyrosequencing on 10 different retrotransposons including 3 different long interspersed nuclear elements (LINEs), 4 short interspersed nuclear elements (SINEs) and 3 human endogenous retroviruses (HERVs). Associations were tested using linear mixed-effects regression models and sex interaction was evaluated. RESULTS A significant sex interaction was observed for AluYb8 (p-value for interaction <0.001, significant at Bonferroni corrected p-value threshold of 0.0025). Boys with the highest TEXB-alpha levels of exposure (third tertile) presented on average a decrease of 0.84% in methylation compared to those in the first tertile (p-value<0.001), while no significant effects were found in girls (p-value=0.134). CONCLUSIONS Our findings suggest that boys may be more susceptible to the effect of exposure to xenoestrogens during prenatal development, producing shifts in DNA methylation of certain sensitive genomic repetitive sequences in a tissue important for fetal growth and development.
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Affiliation(s)
- Nadia Vilahur
- Center for Research in Environmental Epidemiology (CREAL), Barcelona, Catalonia, Spain; Hospital del Mar Medical Research Institute (IMIM), Barcelona, Catalonia, Spain; Genomics and Disease Group, Bioinformatics and Genomics Program, Center for Genomic Regulation (CRG), Barcelona, Catalonia, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain.
| | - Mariona Bustamante
- Center for Research in Environmental Epidemiology (CREAL), Barcelona, Catalonia, Spain; Hospital del Mar Medical Research Institute (IMIM), Barcelona, Catalonia, Spain; Genomics and Disease Group, Bioinformatics and Genomics Program, Center for Genomic Regulation (CRG), Barcelona, Catalonia, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain
| | - Hyang-Min Byun
- Laboratory of Environmental Epigenetics, Exposure Epidemiology and Risk Program, Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA
| | - Mariana F Fernandez
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain; Department of Radiology, Centro de Investigación Biomédica, University of Granada, Granada, Spain; Instituto de Investigación Biosanitaria de Granada, Hospital Universitario San Cecilio, Granada, Spain
| | - Loreto Santa Marina
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain; Subdirección de Salud Pública de Gipuzkoa, Department of Health of the Basque, Spain; Health Research Institute, BIODONOSTIA, Basque Country, Spain
| | - Mikel Basterrechea
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain; Subdirección de Salud Pública de Gipuzkoa, Department of Health of the Basque, Spain; Health Research Institute, BIODONOSTIA, Basque Country, Spain
| | - Ferran Ballester
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain; Centre for Public Health Research (CSISP-FISABIO), Valencia, Spain; University of Valencia, Valencia, Spain
| | - Mario Murcia
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain; Centre for Public Health Research (CSISP-FISABIO), Valencia, Spain; University of Valencia, Valencia, Spain
| | - Adonina Tardón
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain; University of Oviedo, Oviedo, Asturias, Spain
| | - Ana Fernández-Somoano
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain; University of Oviedo, Oviedo, Asturias, Spain
| | - Xavier Estivill
- Hospital del Mar Medical Research Institute (IMIM), Barcelona, Catalonia, Spain; Genomics and Disease Group, Bioinformatics and Genomics Program, Center for Genomic Regulation (CRG), Barcelona, Catalonia, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain; Department of Health and Life Sciences, University Pompeu Fabra (UPF), Barcelona, Catalonia, Spain
| | - Nicolas Olea
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain; Department of Radiology, Centro de Investigación Biomédica, University of Granada, Granada, Spain; Instituto de Investigación Biosanitaria de Granada, Hospital Universitario San Cecilio, Granada, Spain
| | - Jordi Sunyer
- Center for Research in Environmental Epidemiology (CREAL), Barcelona, Catalonia, Spain; Hospital del Mar Medical Research Institute (IMIM), Barcelona, Catalonia, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain; Department of Health and Life Sciences, University Pompeu Fabra (UPF), Barcelona, Catalonia, Spain
| | - Andrea A Baccarelli
- Laboratory of Environmental Epigenetics, Exposure Epidemiology and Risk Program, Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA
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Dynamic Alu methylation during normal development, aging, and tumorigenesis. BIOMED RESEARCH INTERNATIONAL 2014; 2014:784706. [PMID: 25243180 PMCID: PMC4163490 DOI: 10.1155/2014/784706] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 08/16/2014] [Indexed: 12/15/2022]
Abstract
DNA methylation primarily occurs on CpG dinucleotides and plays an important role in transcriptional regulations during tissue development and cell differentiation. Over 25% of CpG dinucleotides in the human genome reside within Alu elements, the most abundant human repeats. The methylation of Alu elements is an important mechanism to suppress Alu transcription and subsequent retrotransposition. Decades of studies revealed that Alu methylation is highly dynamic during early development and aging. Recently, many environmental factors were shown to have a great impact on Alu methylation. In addition, aberrant Alu methylation has been documented to be an early event in many tumors and Alu methylation levels have been associated with tumor aggressiveness. The assessment of the Alu methylation has become an important approach for early diagnosis and/or prognosis of cancer. This review focuses on the dynamic Alu methylation during development, aging, and tumor genesis. The cause and consequence of Alu methylation changes will be discussed.
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Barrow TM, Michels KB. Epigenetic epidemiology of cancer. Biochem Biophys Res Commun 2014; 455:70-83. [PMID: 25124661 DOI: 10.1016/j.bbrc.2014.08.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Revised: 07/15/2014] [Accepted: 08/01/2014] [Indexed: 02/06/2023]
Abstract
Epigenetic epidemiology includes the study of variation in epigenetic traits and the risk of disease in populations. Its application to the field of cancer has provided insight into how lifestyle and environmental factors influence the epigenome and how epigenetic events may be involved in carcinogenesis. Furthermore, it has the potential to bring benefit to patients through the identification of diagnostic markers that enable the early detection of disease and prognostic markers that can inform upon appropriate treatment strategies. However, there are a number of challenges associated with the conduct of such studies, and with the identification of biomarkers that can be applied to the clinical setting. In this review, we delineate the challenges faced in the design of epigenetic epidemiology studies in cancer, including the suitability of blood as a surrogate tissue and the capture of genome-wide DNA methylation. We describe how epigenetic epidemiology has brought insight into risk factors associated with lung, breast, colorectal and bladder cancer and review relevant research. We discuss recent findings on the identification of epigenetic diagnostic and prognostic biomarkers for these cancers.
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Affiliation(s)
- Timothy M Barrow
- Institute for Prevention and Tumor Epidemiology, Freiburg Medical Center, University of Freiburg, 79106, Germany; German Consortium for Translational Cancer Research (DKTK), Heidelberg, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Karin B Michels
- Institute for Prevention and Tumor Epidemiology, Freiburg Medical Center, University of Freiburg, 79106, Germany; Obstetrics and Gynecology Epidemiology Center, Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA.
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Huen K, Yousefi P, Bradman A, Yan L, Harley KG, Kogut K, Eskenazi B, Holland N. Effects of age, sex, and persistent organic pollutants on DNA methylation in children. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2014; 55:209-22. [PMID: 24375655 PMCID: PMC4410811 DOI: 10.1002/em.21845] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 12/06/2013] [Indexed: 05/21/2023]
Abstract
Epigenetic changes such as DNA methylation may be a molecular mechanism through which environmental exposures affect health. Methylation of Alu and long interspersed nucleotide elements (LINE-1) is a well-established measure of DNA methylation often used in epidemiologic studies. Yet, few studies have examined the effects of host factors on LINE-1 and Alu methylation in children. We characterized the relationship of age, sex, and prenatal exposure to persistent organic pollutants (POPs), dichlorodiphenyl trichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), and polybrominated diphenyl ethers (PBDEs), with DNA methylation in a birth cohort of Mexican-American children participating in the CHAMACOS study. We measured Alu and LINE-1 methylation by pyrosequencing bisulfite-treated DNA isolated from whole blood samples collected from newborns and nine-year old children (n = 358). POPs were measured in maternal serum during late pregnancy. Levels of DNA methylation were lower in nine-year olds compared to newborns and were higher in boys compared to girls. Higher prenatal DDT/E exposure was associated with lower Alu methylation at birth, particularly after adjusting for cell type composition (P = 0.02 for o,p' -DDT). Associations of POPs with LINE-1 methylation were only identified after examining the co-exposure of DDT/E with PBDEs simultaneously. Our data suggest that repeat element methylation can be an informative marker of epigenetic differences by age and sex and that prenatal exposure to POPs may be linked to hypomethylation in fetal blood. Accounting for co-exposure to different types of chemicals and adjusting for blood cell types may increase sensitivity of epigenetic analyses for epidemiological studies.
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Affiliation(s)
- Karen Huen
- Center for Children's Environmental Health, School of Public Health, University of California, Berkeley, CA, USA
| | - Paul Yousefi
- Center for Children's Environmental Health, School of Public Health, University of California, Berkeley, CA, USA
| | - Asa Bradman
- Center for Children's Environmental Health, School of Public Health, University of California, Berkeley, CA, USA
| | | | - Kim G. Harley
- Center for Children's Environmental Health, School of Public Health, University of California, Berkeley, CA, USA
| | - Katherine Kogut
- Center for Children's Environmental Health, School of Public Health, University of California, Berkeley, CA, USA
| | - Brenda Eskenazi
- Center for Children's Environmental Health, School of Public Health, University of California, Berkeley, CA, USA
| | - Nina Holland
- Center for Children's Environmental Health, School of Public Health, University of California, Berkeley, CA, USA
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