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Keshawarz A, Joehanes R, Guan W, Huan T, DeMeo DL, Grove ML, Fornage M, Levy D, O’Connor G. Longitudinal change in blood DNA epigenetic signature after smoking cessation. Epigenetics 2022; 17:1098-1109. [PMID: 34570667 PMCID: PMC9542417 DOI: 10.1080/15592294.2021.1985301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/20/2021] [Accepted: 09/21/2021] [Indexed: 12/14/2022] Open
Abstract
Cigarette smoking is associated with epigenetic changes that may be reversible following smoking cessation. Whole blood DNA methylation was evaluated in Framingham Heart Study Offspring (n = 169) and Third Generation (n = 30) cohort participants at two study visits 6 years apart and in Atherosclerosis Risk in Communities (ARIC) study (n = 222) participants at two study visits 20 years apart. Changes in DNA methylation (delta β values) at 483,565 cytosine-phosphate-guanine (CpG) sites and differentially methylated regions (DMRs) were compared between participants who were current, former, or never smokers at both visits (current-current, former-former, never-never, respectively), versus those who quit in the interim (current-former). Interim quitters had more hypermethylation at four CpGs annotated to AHRR, one CpG annotated to F2RL3, and one intergenic CpG (cg21566642) compared with current-current smokers (FDR < 0.02 for all), and two significant DMRs were identified. While there were no significant differentially methylated CpGs in the comparison of interim quitters and former-former smokers, 106 DMRs overlapping with small nucleolar RNA were identified. As compared with all non-smokers, current-current smokers additionally had more hypermethylation at two CpG sites annotated to HIVEP3 and TMEM126A, respectively, and another intergenic CpG (cg14339116). Gene transcripts associated with smoking cessation were implicated in immune responses, cell homoeostasis, and apoptosis. Smoking cessation is associated with early reversion of blood DNA methylation changes at CpG sites annotated to AHRR and F2RL3 towards those of never smokers. Associated gene expression suggests a role of longitudinal smoking-related DNA methylation changes in immune response processes.
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Affiliation(s)
- Amena Keshawarz
- Population Sciences Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
- Framingham Heart Study, Framingham, MA, USA
| | - Roby Joehanes
- Population Sciences Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
- Framingham Heart Study, Framingham, MA, USA
| | - Weihua Guan
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, MN, USA
| | - Tianxiao Huan
- Framingham Heart Study, Framingham, MA, USA
- Department of Ophthalmology and Visual Sciences, University of Massachusetts Medical School, Worcester, MA, USA
| | - Dawn L. DeMeo
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Boston, MA, USA
- Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital, Boston, MA, USA
| | - Megan L. Grove
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Myriam Fornage
- McGovern Medical School and Human Genetics Center, School of Public Health, The University of Texas Health Science Center at Houston, Brown Foundation Institute of Molecular Medicine, Houston, TX, USA
| | - Daniel Levy
- Population Sciences Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - George O’Connor
- Pulmonary Center, Boston University School of Medicine, Boston, MA, USA
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2
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Nishizaki SS, Boyle AP. SEMplMe: a tool for integrating DNA methylation effects in transcription factor binding affinity predictions. BMC Bioinformatics 2022; 23:317. [PMID: 35927613 PMCID: PMC9351228 DOI: 10.1186/s12859-022-04865-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 07/28/2022] [Indexed: 12/02/2022] Open
Abstract
MOTIVATION Aberrant DNA methylation in transcription factor binding sites has been shown to lead to anomalous gene regulation that is strongly associated with human disease. However, the majority of methylation-sensitive positions within transcription factor binding sites remain unknown. Here we introduce SEMplMe, a computational tool to generate predictions of the effect of methylation on transcription factor binding strength in every position within a transcription factor's motif. RESULTS SEMplMe uses ChIP-seq and whole genome bisulfite sequencing to predict effects of methylation within binding sites. SEMplMe validates known methylation sensitive and insensitive positions within a binding motif, identifies cell type specific transcription factor binding driven by methylation, and outperforms SELEX-based predictions for CTCF. These predictions can be used to identify aberrant sites of DNA methylation contributing to human disease. AVAILABILITY AND IMPLEMENTATION SEMplMe is available from https://github.com/Boyle-Lab/SEMplMe .
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Affiliation(s)
- Sierra S Nishizaki
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Alan P Boyle
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, 48109, USA.
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109, USA.
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3
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Chmielowiec J, Chmielowiec K, Strońska-Pluta A, Suchanecka A, Humińska-Lisowska K, Lachowicz M, Niewczas M, Białecka M, Śmiarowska M, Grzywacz A. Methylation in the Promoter Region of the Dopamine Transporter DAT1 Gene in People Addicted to Nicotine. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19148602. [PMID: 35886451 PMCID: PMC9321476 DOI: 10.3390/ijerph19148602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/30/2022] [Accepted: 07/12/2022] [Indexed: 01/27/2023]
Abstract
The dopaminergic system is a crucial element of the addiction processes. The dopamine transporter modulates the dynamics and levels of released dopamine in the synaptic cleft. Therefore, regulation of dopamine transporter (DAT1) gene expression is critical for maintaining homeostasis in the dopaminergic system. The aim of our study is evaluation of the methylation status of 33 CpG islands located in the DAT1 gene promoter region related to nicotine dependency. We investigated 142 nicotine-dependent subjects and 238 controls. Our results show that as many as 14 of the 33 CpG islands tested had statistically significantly higher methylation in the nicotine-dependent group compared to the control group. After applying Bonferroni correction, the total number of methylation sites was also significantly higher in the dependent subjects group. The analysis of the methylation status of particular CpG sites revealed a new direction of research regarding the biological aspects of nicotine addiction.
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Affiliation(s)
- Jolanta Chmielowiec
- Department of Hygiene and Epidemiology, Collegium Medicum, University of Zielona Góra, 65-046 Zielona Gora, Poland; (J.C.); (K.C.)
| | - Krzysztof Chmielowiec
- Department of Hygiene and Epidemiology, Collegium Medicum, University of Zielona Góra, 65-046 Zielona Gora, Poland; (J.C.); (K.C.)
| | - Aleksandra Strońska-Pluta
- Independent Laboratory of Health Promotion, Pomeranian Medical University in Szczecin, 70-204 Szczecin, Poland; (A.S.-P.); (A.S.)
| | - Aleksandra Suchanecka
- Independent Laboratory of Health Promotion, Pomeranian Medical University in Szczecin, 70-204 Szczecin, Poland; (A.S.-P.); (A.S.)
| | - Kinga Humińska-Lisowska
- Faculty of Physical Education, Gdansk University of Physical Education and Sport, 80-336 Gdansk, Poland;
| | - Milena Lachowicz
- Department of Psychology, Gdansk University of Physical Education and Sport, 80-336 Gdansk, Poland;
| | - Marta Niewczas
- Faculty of Physical Education, University of Rzeszow, 35-959 Rzeszow, Poland;
| | - Monika Białecka
- Department of Pharmacokinetics and Therapeutic Drug Monitoring, Pomeranian Medical University, 70-111 Szczecin, Poland; (M.B.); (M.Ś.)
| | - Małgorzata Śmiarowska
- Department of Pharmacokinetics and Therapeutic Drug Monitoring, Pomeranian Medical University, 70-111 Szczecin, Poland; (M.B.); (M.Ś.)
| | - Anna Grzywacz
- Independent Laboratory of Health Promotion, Pomeranian Medical University in Szczecin, 70-204 Szczecin, Poland; (A.S.-P.); (A.S.)
- Correspondence: ; Tel.: +48-91441-47-46
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4
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Lemma RB, Fleischer T, Martinsen E, Ledsaak M, Kristensen V, Eskeland R, Gabrielsen OS, Mathelier A. Pioneer transcription factors are associated with the modulation of DNA methylation patterns across cancers. Epigenetics Chromatin 2022; 15:13. [PMID: 35440061 PMCID: PMC9016969 DOI: 10.1186/s13072-022-00444-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/14/2022] [Indexed: 12/15/2022] Open
Abstract
Methylation of cytosines on DNA is a prominent modification associated with gene expression regulation. Aberrant DNA methylation patterns have recurrently been linked to dysregulation of the regulatory program in cancer cells. To shed light on the underlying molecular mechanism driving this process, we hypothesised that aberrant methylation patterns could be controlled by the binding of specific transcription factors (TFs) across cancer types. By combining DNA methylation arrays and gene expression data with TF binding sites (TFBSs), we explored the interplay between TF binding and DNA methylation in 19 cancer types. We performed emQTL (expression–methylation quantitative trait loci) analyses independently in each cancer type and identified 13 TFs whose expression levels are correlated with local DNA methylation patterns around their binding sites in at least 2 cancer types. The 13 TFs are mainly associated with local demethylation and are enriched for pioneer function, suggesting a specific role for these TFs in modulating chromatin structure and transcription in cancer patients. Furthermore, we confirmed that de novo methylation is precluded across cancers at CpGs lying in genomic regions enriched for TF binding signatures associated with SP1, CTCF, NRF1, GABPA, KLF9, and/or YY1. The modulation of DNA methylation associated with TF binding was observed at cis-regulatory regions controlling immune- and cancer-associated pathways, corroborating that the emQTL signals were derived from both cancer and tumor-infiltrating cells. As a case example, we experimentally confirmed that FOXA1 knock-down is associated with higher methylation in regions bound by FOXA1 in breast cancer MCF-7 cells. Finally, we reported physical interactions between FOXA1 with TET1 and TET2 both in an in vitro setup and in vivo at physiological levels in MCF-7 cells, adding further support for FOXA1 attracting TET1 and TET2 to induce local demethylation in cancer cells.
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Affiliation(s)
- Roza Berhanu Lemma
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership, University of Oslo, Oslo, Norway
| | - Thomas Fleischer
- Department of Cancer Genetics, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Emily Martinsen
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership, University of Oslo, Oslo, Norway.,Institute of Basic Medical Sciences, Department of Molecular Medicine, and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Marit Ledsaak
- Institute of Basic Medical Sciences, Department of Molecular Medicine, and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Vessela Kristensen
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Ragnhild Eskeland
- Institute of Basic Medical Sciences, Department of Molecular Medicine, and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | | | - Anthony Mathelier
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership, University of Oslo, Oslo, Norway. .,Department of Medical Genetics, Oslo University Hospital, Oslo, Norway.
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5
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Head and Neck Cancers Are Not Alike When Tarred with the Same Brush: An Epigenetic Perspective from the Cancerization Field to Prognosis. Cancers (Basel) 2021; 13:cancers13225630. [PMID: 34830785 PMCID: PMC8616074 DOI: 10.3390/cancers13225630] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/30/2021] [Accepted: 11/02/2021] [Indexed: 12/26/2022] Open
Abstract
Simple Summary Squamous cell carcinomas affect different head and neck subsites and, although these tumors arise from the same epithelial lining and share risk factors, they differ in terms of clinical behavior and molecular carcinogenesis mechanisms. Differences between HPV-negative and HPV-positive tumors are those most frequently explored, but further data suggest that the molecular heterogeneity observed among head and neck subsites may go beyond HPV infection. In this review, we explore how alterations of DNA methylation and microRNA expression contribute to head and neck squamous cell carcinoma (HNSCC) development and progression. The association of these epigenetic alterations with risk factor exposure, early carcinogenesis steps, transformation risk, and prognosis are described. Finally, we discuss the potential application of the use of epigenetic biomarkers in HNSCC. Abstract Head and neck squamous cell carcinomas (HNSCC) are among the ten most frequent types of cancer worldwide and, despite all efforts, are still diagnosed at late stages and show poor overall survival. Furthermore, HNSCC patients often experience relapses and the development of second primary tumors, as a consequence of the field cancerization process. Therefore, a better comprehension of the molecular mechanisms involved in HNSCC development and progression may enable diagnosis anticipation and provide valuable tools for prediction of prognosis and response to therapy. However, the different biological behavior of these tumors depending on the affected anatomical site and risk factor exposure, as well as the high genetic heterogeneity observed in HNSCC are major obstacles in this pursue. In this context, epigenetic alterations have been shown to be common in HNSCC, to discriminate the tumor anatomical subsites, to be responsive to risk factor exposure, and show promising results in biomarker development. Based on this, this review brings together the current knowledge on alterations of DNA methylation and microRNA expression in HNSCC natural history, focusing on how they contribute to each step of the process and on their applicability as biomarkers of exposure, HNSCC development, progression, and response to therapy.
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6
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Alcaraz J, Ikemori R, Llorente A, Díaz-Valdivia N, Reguart N, Vizoso M. Epigenetic Reprogramming of Tumor-Associated Fibroblasts in Lung Cancer: Therapeutic Opportunities. Cancers (Basel) 2021; 13:cancers13153782. [PMID: 34359678 PMCID: PMC8345093 DOI: 10.3390/cancers13153782] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/23/2021] [Accepted: 07/24/2021] [Indexed: 12/21/2022] Open
Abstract
Simple Summary Lung cancer is the leading cause of cancer death among both men and women, partly due to limited therapy responses. New avenues of knowledge are indicating that lung cancer cells do not form a tumor in isolation but rather obtain essential support from their surrounding host tissue rich in altered fibroblasts. Notably, there is growing evidence that tumor progression and even the current limited responses to therapies could be prevented by rescuing the normal behavior of fibroblasts, which are critical housekeepers of normal tissue function. For this purpose, it is key to improve our understanding of the molecular mechanisms driving the pathologic alterations of fibroblasts in cancer. This work provides a comprehensive review of the main molecular mechanisms involved in fibroblast transformation based on epigenetic reprogramming, and summarizes emerging therapeutic approaches to prevent or overcome the pathologic effects of tumor-associated fibroblasts. Abstract Lung cancer is the leading cause of cancer-related death worldwide. The desmoplastic stroma of lung cancer and other solid tumors is rich in tumor-associated fibroblasts (TAFs) exhibiting an activated/myofibroblast-like phenotype. There is growing awareness that TAFs support key steps of tumor progression and are epigenetically reprogrammed compared to healthy fibroblasts. Although the mechanisms underlying such epigenetic reprogramming are incompletely understood, there is increasing evidence that they involve interactions with either cancer cells, pro-fibrotic cytokines such as TGF-β, the stiffening of the surrounding extracellular matrix, smoking cigarette particles and other environmental cues. These aberrant interactions elicit a global DNA hypomethylation and a selective transcriptional repression through hypermethylation of the TGF-β transcription factor SMAD3 in lung TAFs. Likewise, similar DNA methylation changes have been reported in TAFs from other cancer types, as well as histone core modifications and altered microRNA expression. In this review we summarize the evidence of the epigenetic reprogramming of TAFs, how this reprogramming contributes to the acquisition and maintenance of a tumor-promoting phenotype, and how it provides novel venues for therapeutic intervention, with a special focus on lung TAFs.
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Affiliation(s)
- Jordi Alcaraz
- Unit of Biophysics and Bioengineering, Department of Biomedicine, School of Medicine and Health Sciences, Universitat de Barcelona, 08036 Barcelona, Spain; (R.I.); (A.L.); (N.D.-V.)
- Thoracic Oncology Unit, Hospital Clinic Barcelona, 08036 Barcelona, Spain;
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), 08028 Barcelona, Spain
- Correspondence: (J.A.); (M.V.)
| | - Rafael Ikemori
- Unit of Biophysics and Bioengineering, Department of Biomedicine, School of Medicine and Health Sciences, Universitat de Barcelona, 08036 Barcelona, Spain; (R.I.); (A.L.); (N.D.-V.)
| | - Alejandro Llorente
- Unit of Biophysics and Bioengineering, Department of Biomedicine, School of Medicine and Health Sciences, Universitat de Barcelona, 08036 Barcelona, Spain; (R.I.); (A.L.); (N.D.-V.)
| | - Natalia Díaz-Valdivia
- Unit of Biophysics and Bioengineering, Department of Biomedicine, School of Medicine and Health Sciences, Universitat de Barcelona, 08036 Barcelona, Spain; (R.I.); (A.L.); (N.D.-V.)
| | - Noemí Reguart
- Thoracic Oncology Unit, Hospital Clinic Barcelona, 08036 Barcelona, Spain;
- Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Miguel Vizoso
- Division of Molecular Pathology, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
- Correspondence: (J.A.); (M.V.)
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7
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Lee BH, Rhie SK. Molecular and computational approaches to map regulatory elements in 3D chromatin structure. Epigenetics Chromatin 2021; 14:14. [PMID: 33741028 PMCID: PMC7980343 DOI: 10.1186/s13072-021-00390-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 03/08/2021] [Indexed: 12/19/2022] Open
Abstract
Epigenetic marks do not change the sequence of DNA but affect gene expression in a cell-type specific manner by altering the activities of regulatory elements. Development of new molecular biology assays, sequencing technologies, and computational approaches enables us to profile the human epigenome in three-dimensional structure genome-wide. Here we describe various molecular biology techniques and bioinformatic tools that have been developed to measure the activities of regulatory elements and their chromatin interactions. Moreover, we list currently available three-dimensional epigenomic data sets that are generated in various human cell types and tissues to assist in the design and analysis of research projects.
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Affiliation(s)
- Beoung Hun Lee
- Department of Biochemistry and Molecular Medicine and the Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA
| | - Suhn K Rhie
- Department of Biochemistry and Molecular Medicine and the Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA.
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8
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Abstract
Messenger RNAs (mRNAs) consist of a coding region (open reading frame (ORF)) and two untranslated regions (UTRs), 5'UTR and 3'UTR. Ribosomes travel along the coding region, translating nucleotide triplets (called codons) to a chain of amino acids. The coding region was long believed to mainly encode the amino acid content of proteins, whereas regulatory signals reside in the UTRs and in other genomic regions. However, in recent years we have learned that the ORF is expansively populated with various regulatory signals, or codes, which are related to all gene expression steps and additional intracellular aspects. In this paper, we review the current knowledge related to overlapping codes inside the coding regions, such as the influence of synonymous codon usage on translation speed (and, in turn, the effect of translation speed on protein folding), ribosomal frameshifting, mRNA stability, methylation, splicing, transcription and more. All these codes come together and overlap in the ORF sequence, ensuring production of the right protein at the right time.
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Affiliation(s)
- Shaked Bergman
- Department of Biomedical Engineering, Tel-Aviv University, Tel Aviv, Israel
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9
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Maas SCE, Vidaki A, Wilson R, Teumer A, Liu F, van Meurs JBJ, Uitterlinden AG, Boomsma DI, de Geus EJC, Willemsen G, van Dongen J, van der Kallen CJH, Slagboom PE, Beekman M, van Heemst D, van den Berg LH, Duijts L, Jaddoe VWV, Ladwig KH, Kunze S, Peters A, Ikram MA, Grabe HJ, Felix JF, Waldenberger M, Franco OH, Ghanbari M, Kayser M. Validated inference of smoking habits from blood with a finite DNA methylation marker set. Eur J Epidemiol 2019; 34:1055-1074. [PMID: 31494793 PMCID: PMC6861351 DOI: 10.1007/s10654-019-00555-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Accepted: 08/22/2019] [Indexed: 12/18/2022]
Abstract
Inferring a person’s smoking habit and history from blood is relevant for complementing or replacing self-reports in epidemiological and public health research, and for forensic applications. However, a finite DNA methylation marker set and a validated statistical model based on a large dataset are not yet available. Employing 14 epigenome-wide association studies for marker discovery, and using data from six population-based cohorts (N = 3764) for model building, we identified 13 CpGs most suitable for inferring smoking versus non-smoking status from blood with a cumulative Area Under the Curve (AUC) of 0.901. Internal fivefold cross-validation yielded an average AUC of 0.897 ± 0.137, while external model validation in an independent population-based cohort (N = 1608) achieved an AUC of 0.911. These 13 CpGs also provided accurate inference of current (average AUCcrossvalidation 0.925 ± 0.021, AUCexternalvalidation0.914), former (0.766 ± 0.023, 0.699) and never smoking (0.830 ± 0.019, 0.781) status, allowed inferring pack-years in current smokers (10 pack-years 0.800 ± 0.068, 0.796; 15 pack-years 0.767 ± 0.102, 0.752) and inferring smoking cessation time in former smokers (5 years 0.774 ± 0.024, 0.760; 10 years 0.766 ± 0.033, 0.764; 15 years 0.767 ± 0.020, 0.754). Model application to children revealed highly accurate inference of the true non-smoking status (6 years of age: accuracy 0.994, N = 355; 10 years: 0.994, N = 309), suggesting prenatal and passive smoking exposure having no impact on model applications in adults. The finite set of DNA methylation markers allow accurate inference of smoking habit, with comparable accuracy as plasma cotinine use, and smoking history from blood, which we envision becoming useful in epidemiology and public health research, and in medical and forensic applications.
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Affiliation(s)
- Silvana C E Maas
- Department of Epidemiology, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands.,Department of Genetic Identification, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
| | - Athina Vidaki
- Department of Genetic Identification, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
| | - Rory Wilson
- Research Unit of Molecular Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.,Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Alexander Teumer
- Institute for Community Medicine, University Medicine Greifswald, Walther-Rathenau-Str. 48, 17475, Greifswald, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Greifswald, 17475 Greifswald, Germany
| | - Fan Liu
- Department of Genetic Identification, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands.,Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, NO.1 Beichen West Road, Chaoyang District, 100101 Beijing, People's Republic of China.,University of Chinese Academy of Sciences, No.19A Yuquan Road, Shijingshan District, 100049 Beijing, People's Republic of China
| | - Joyce B J van Meurs
- Department of Epidemiology, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands.,Department of Internal Medicine, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
| | - André G Uitterlinden
- Department of Epidemiology, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands.,Department of Internal Medicine, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
| | - Dorret I Boomsma
- Department of Biological Psychology, Vrije Universiteit, Van der Boechorststraat 7-9, 1081 BT, Amsterdam, The Netherlands
| | - Eco J C de Geus
- Department of Biological Psychology, Vrije Universiteit, Van der Boechorststraat 7-9, 1081 BT, Amsterdam, The Netherlands
| | - Gonneke Willemsen
- Department of Biological Psychology, Vrije Universiteit, Van der Boechorststraat 7-9, 1081 BT, Amsterdam, The Netherlands
| | - Jenny van Dongen
- Department of Biological Psychology, Vrije Universiteit, Van der Boechorststraat 7-9, 1081 BT, Amsterdam, The Netherlands
| | - Carla J H van der Kallen
- Department of Internal Medicine, Maastricht University Medical Center, Randwycksingel 35, 6229 EG, Maastricht, The Netherlands.,Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
| | - P Eline Slagboom
- Molecular Epidemiology, Department of Biomedical Data Sciences, Leiden University Medical Center, P.O. box 9600, 2300 RC, Leiden, The Netherlands
| | - Marian Beekman
- Molecular Epidemiology, Department of Biomedical Data Sciences, Leiden University Medical Center, P.O. box 9600, 2300 RC, Leiden, The Netherlands
| | - Diana van Heemst
- Gerontology and Geriatrics, Department of Internal Medicine, Leiden University Medical Center, P.O. box 9600, 2300 RC, Leiden, The Netherlands
| | - Leonard H van den Berg
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Postbus 85500, 3508 GA, Utrecht, The Netherlands
| | | | - Liesbeth Duijts
- Division of Respiratory Medicine and Allergology and Division of Neonatology, Department of Pediatrics, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
| | - Vincent W V Jaddoe
- Department of Epidemiology, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands.,The Generation R Study Group, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands.,Department of Pediatrics, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
| | - Karl-Heinz Ladwig
- Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Sonja Kunze
- Research Unit of Molecular Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.,Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Annette Peters
- Research Unit of Molecular Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.,Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, 80802 Munich, Germany.,Institute for Medical Informatics, Biometrics and Epidemiology, Ludwig-Maximilians-Universität (LMU) Munich, Marchioninistr. 15, 81377 Munich, Germany
| | - M Arfan Ikram
- Department of Epidemiology, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
| | - Hans J Grabe
- Department of Psychiatry and Psychotherapy, University Medicine Greifswald, Ellernholzstraße 1-2, 17475, Greifswald, Germany
| | - Janine F Felix
- Department of Epidemiology, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands.,The Generation R Study Group, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands.,Department of Pediatrics, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
| | - Melanie Waldenberger
- Research Unit of Molecular Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.,Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, 80802 Munich, Germany
| | - Oscar H Franco
- Department of Epidemiology, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
| | - Mohsen Ghanbari
- Department of Epidemiology, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands. .,Department of Genetics, School of Medicine, Mashhad University of Medical Science, PO Box 91735-951, 9133913716 Mashhad, Iran.
| | - Manfred Kayser
- Department of Genetic Identification, Erasmus MC University Medical Center Rotterdam, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands.
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10
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Kuehner JN, Bruggeman EC, Wen Z, Yao B. Epigenetic Regulations in Neuropsychiatric Disorders. Front Genet 2019; 10:268. [PMID: 31019524 PMCID: PMC6458251 DOI: 10.3389/fgene.2019.00268] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/11/2019] [Indexed: 12/14/2022] Open
Abstract
Precise genetic and epigenetic spatiotemporal regulation of gene expression is critical for proper brain development, function and circuitry formation in the mammalian central nervous system. Neuronal differentiation processes are tightly regulated by epigenetic mechanisms including DNA methylation, histone modifications, chromatin remodelers and non-coding RNAs. Dysregulation of any of these pathways is detrimental to normal neuronal development and functions, which can result in devastating neuropsychiatric disorders, such as depression, schizophrenia and autism spectrum disorders. In this review, we focus on the current understanding of epigenetic regulations in brain development and functions, as well as their implications in neuropsychiatric disorders.
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Affiliation(s)
- Janise N Kuehner
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States
| | - Emily C Bruggeman
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States
| | - Zhexing Wen
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States.,Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, United States
| | - Bing Yao
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States
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11
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Peng H, Guo T, Chen Z, Zhang H, Cai S, Yang M, Chen P, Guan C, Fang X. Hypermethylation of mitochondrial transcription factor A induced by cigarette smoke is associated with chronic obstructive pulmonary disease. Exp Lung Res 2019; 45:101-111. [PMID: 31198067 DOI: 10.1080/01902148.2018.1556748] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/21/2018] [Accepted: 12/04/2018] [Indexed: 02/08/2023]
Abstract
Purpose of the study: Cigarette smoking is a leading environmental contributor to chronic obstructive pulmonary disease (COPD), but its epigenetic regulation of mtTFA gene remains elusive. This study aims to explore the relationship of DNA methylation of mtTFA and cigarette smoking in COPD. Materials and Methods: We analyzed DNA methylation on mtTFA promoters in clinical samples from COPD patients and subjects with normal pulmonary function. Expression of mtTFA mRNA in the clinical samples and mtTFA mRNA and protein in human umbilical vein endothelial cells(HUVECs) treated with cigarette smoke extract (CSE) was evaluated. mtTFA mRNA and protein levels were measured to determine effects of demethylation agents on CSE-treated HUVECs. Results: The DNA methylation level of the mtTFA promoter was significantly increased in COPD group. Expression of mtTFA mRNA was downregulated in the lungs as a consequence of hypermethylation of mtTFA promoter. Expression of mtTFA mRNA and protein was downregulated in CSE-treated HUVECs as a consequence of hypermethylation of the mtTFA promoter. mtTFA expression in CSE-treated HUVECs was restored by the methylation inhibitor, 5-aza-2'-deoxycytidine(AZA). Conclusions: Cigarette smoke-induced hypermethylation of the mtTFA promoter is related to the initiation and progression of COPD. Our finding may provide a new strategy for the intervention of COPD by developing demethylation agents targeting mtTFA hypermethylation.
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Affiliation(s)
- Hong Peng
- a Department of Respiratory and Critical Care Medicine , The Second Xiangya Hospital of Central-South University , Changsha , PR China
- b b The Respiratory Disease Research Institute of Central South University , Changsha , PR China
- c c The Respiratory Disease Diagnosis and Treatment Center of Hunan Province , Changsha , PR China
| | - Ting Guo
- a Department of Respiratory and Critical Care Medicine , The Second Xiangya Hospital of Central-South University , Changsha , PR China
- b b The Respiratory Disease Research Institute of Central South University , Changsha , PR China
- c c The Respiratory Disease Diagnosis and Treatment Center of Hunan Province , Changsha , PR China
| | - Zhiyong Chen
- d d Department of Urology , Xiangya Hospital of Central-South University , Changsha , PR China
| | - Hongliang Zhang
- a Department of Respiratory and Critical Care Medicine , The Second Xiangya Hospital of Central-South University , Changsha , PR China
- b b The Respiratory Disease Research Institute of Central South University , Changsha , PR China
- c c The Respiratory Disease Diagnosis and Treatment Center of Hunan Province , Changsha , PR China
| | - Shan Cai
- a Department of Respiratory and Critical Care Medicine , The Second Xiangya Hospital of Central-South University , Changsha , PR China
- b b The Respiratory Disease Research Institute of Central South University , Changsha , PR China
- c c The Respiratory Disease Diagnosis and Treatment Center of Hunan Province , Changsha , PR China
| | - Min Yang
- a Department of Respiratory and Critical Care Medicine , The Second Xiangya Hospital of Central-South University , Changsha , PR China
- b b The Respiratory Disease Research Institute of Central South University , Changsha , PR China
- c c The Respiratory Disease Diagnosis and Treatment Center of Hunan Province , Changsha , PR China
| | - Ping Chen
- a Department of Respiratory and Critical Care Medicine , The Second Xiangya Hospital of Central-South University , Changsha , PR China
- b b The Respiratory Disease Research Institute of Central South University , Changsha , PR China
- c c The Respiratory Disease Diagnosis and Treatment Center of Hunan Province , Changsha , PR China
| | - Chaxiang Guan
- e Physiological Research Center , Xiangya Medical School of Central-South University , Changsha , PR China
| | - Xiang Fang
- f Department of Neurology , University of Texas Medical Branch , Galveston , Texas, USA
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12
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Gene activation precedes DNA demethylation in response to infection in human dendritic cells. Proc Natl Acad Sci U S A 2019; 116:6938-6943. [PMID: 30886108 PMCID: PMC6452747 DOI: 10.1073/pnas.1814700116] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Immune response to infection is accompanied by active demethylation of thousands of CpG sites. Yet, the causal relationship between changes in DNA methylation and gene expression during infection remains to be elucidated. Here, we investigated the role of DNA methylation in the regulation of innate immune responses to bacterial infections. We found that virtually all changes in gene expression in response to infection occur prior to detectable alterations in the methylome. We also found that the binding of most infection-induced transcription factors precedes loss of methylation. Collectively, our results show that changes in methylation are a downstream consequence of transcription factor binding, and not essential for the establishment of the core regulatory program engaged upon infection. DNA methylation is considered to be a relatively stable epigenetic mark. However, a growing body of evidence indicates that DNA methylation levels can change rapidly; for example, in innate immune cells facing an infectious agent. Nevertheless, the causal relationship between changes in DNA methylation and gene expression during infection remains to be elucidated. Here, we generated time-course data on DNA methylation, gene expression, and chromatin accessibility patterns during infection of human dendritic cells with Mycobacterium tuberculosis. We found that the immune response to infection is accompanied by active demethylation of thousands of CpG sites overlapping distal enhancer elements. However, virtually all changes in gene expression in response to infection occur before detectable changes in DNA methylation, indicating that the observed losses in methylation are a downstream consequence of transcriptional activation. Footprinting analysis revealed that immune-related transcription factors (TFs), such as NF-κB/Rel, are recruited to enhancer elements before the observed losses in methylation, suggesting that DNA demethylation is mediated by TF binding to cis-acting elements. Collectively, our results show that DNA demethylation plays a limited role to the establishment of the core regulatory program engaged upon infection.
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13
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The DNA Methylation Machinery. Clin Epigenetics 2019. [DOI: 10.1007/978-981-13-8958-0_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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14
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Hamad MF, Dayyih WAA, Laqqan M, AlKhaled Y, Montenarh M, Hammadeh ME. The status of global DNA methylation in the spermatozoa of smokers and non-smokers. Reprod Biomed Online 2018; 37:581-589. [PMID: 30366840 DOI: 10.1016/j.rbmo.2018.08.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 08/28/2018] [Accepted: 08/29/2018] [Indexed: 01/06/2023]
Abstract
RESEARCH QUESTION Does regular smoking affect semen quality and the levels of DNA methylation in mature human spermatozoa? DESIGN Spermatozoa from 109 men were evaluated (55 smokers and 54 non-smokers). DNA was extracted from purified spermatozoa, and DNA methylation was quantified by enzyme-linked immunosorbent assay (ELISA). RESULTS Global DNA methylation of non-smokers is significantly lower (P < 0.001) than that of smokers (4.85 ± 2.72 and 7.08 ± 1.77 ng/μl, respectively). Moreover, the mean global DNA methylation levels were significantly correlated (r = 0.22;P = 0.02) with non-condensed chromatin in the spermatozoa. Levels of non-condensed chromatin were significantly higher (P < 0.001) in smokers (29.75 ± 9.38%) compared with non-smokers (20.96 ± 11.31%). Furthermore, global sperm DNA methylation was negatively correlated with high significance (P < 0.010) with sperm: count (r = -0.27), motility (r = -0.30) and vitality (r = -0.26). CONCLUSION Smoking interferes with DNA methylation. Also, DNA methylation is significantly correlated with sperm parameters and sperm non-condensed chromatin. These data emphasize another detrimental effect of smoking on male fertility. DNA methylation may, therefore, be considered as a fertility marker in men.
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Affiliation(s)
- Mohammed F Hamad
- Department of Basic Sciences, College of Science and Health Professions, King Saud Bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia; IVF and Andrology Laboratory, Department of Obstetrics and Gynaecology, Saarland University Hospital, Building 9, Homburg/Saar 66424, Germany; Department of Medical Biochemistry and Molecular Biology, Saarland University, Building 44, 66424, Homburg/Saar, Germany.
| | - Wael A Abu Dayyih
- Department of Pharmaceutical Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy and Medical Sciences, University of Petra, Amman, Jordan
| | - Mohammad Laqqan
- IVF and Andrology Laboratory, Department of Obstetrics and Gynaecology, Saarland University Hospital, Building 9, Homburg/Saar 66424, Germany
| | - Yasir AlKhaled
- IVF and Andrology Laboratory, Department of Obstetrics and Gynaecology, Saarland University Hospital, Building 9, Homburg/Saar 66424, Germany
| | - Mathias Montenarh
- Department of Medical Biochemistry and Molecular Biology, Saarland University, Building 44, 66424, Homburg/Saar, Germany
| | - Mohammed E Hammadeh
- IVF and Andrology Laboratory, Department of Obstetrics and Gynaecology, Saarland University Hospital, Building 9, Homburg/Saar 66424, Germany
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15
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Alghanim H, Wu W, McCord B. DNA methylation assay based on pyrosequencing for determination of smoking status. Electrophoresis 2018; 39:2806-2814. [PMID: 29956353 DOI: 10.1002/elps.201800098] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/30/2018] [Accepted: 06/01/2018] [Indexed: 11/06/2022]
Abstract
The goal of this study was to utilize pyrosequencing to identify CpG sites indicative of tobacco smoking using DNA sequences surrounding ten frequently reported smoking-related CpGs. Initially, six genetic loci were investigated including AHRR, 2q37, 6p21.33, GFI1, F2RL3, and MYO1G in order to detect novel CpG sites associated with tobacco smoking. The methylation data revealed a set of 23 consecutive CpG sites in blood (Chr5:373,115-Chr5:373,653) that were significantly hypomethylated in current smokers. In addition, 10 of these 23 CpGs were also significantly hypomethylated in the saliva of current smokers. The most significant CpG sites were located at Chr5:373,490 in blood and Chr5:373,476 in saliva with a decrease in methylation in current smokers of 42.3% and 21.3% respectively. In the model-building steps of this study, a quick 4-CpG assay was developed. The assay consisted of the top ranked CpG sites in blood and saliva. The assay was applied in a leave-one-out approach to test its ability to infer an individual's self-identified history of smoking habits. A multinomial logistic regression model (MLR) containing all 4 CpG sites gave the most accurate results in blood and saliva. In blood, the model correctly predicted 90.0% of current smokers, 66.7% of former smokers, and 84.9% of never smokers. In addition, the MLR model correctly predicted 86.9% of current smokers, 54.5% of former smokers, and 77.8% of never smokers in saliva. These results demonstrate that this pyrosequencing-based assay can provide an effective tool for identifying individuals who smoke tobacco, particularly when using epigenetic markers in blood.
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Affiliation(s)
- Hussain Alghanim
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA.,General Department of Forensic Science and Criminology, Dubai Police, Dubai, UAE
| | - Wensong Wu
- Department of Mathematics and Statistics, Florida International University, Miami, FL, USA
| | - Bruce McCord
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA
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16
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Chakraborty A, Viswanathan P. Methylation-Demethylation Dynamics: Implications of Changes in Acute Kidney Injury. Anal Cell Pathol (Amst) 2018. [DOI: https://doi.org/10.1155/2018/8764384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Over the years, the epigenetic landscape has grown increasingly complex. Until recently, methylation of DNA and histones was considered one of the most important epigenetic modifications. However, with the discovery of enzymes involved in the demethylation process, several exciting prospects have emerged that focus on the dynamic regulation of methylation and its crucial role in development and disease. An interplay of the methylation-demethylation machinery controls the process of gene expression. Since acute kidney injury (AKI), a major risk factor for chronic kidney disease and death, is characterised by aberrant expression of genes, understanding the dynamics of methylation and demethylation will provide new insights into the intricacies of the disease. Research on epigenetics in AKI has only made its mark in the recent years but has provided compelling evidence that implicates the involvement of methylation and demethylation changes in its pathophysiology. In this review, we explore the role of methylation and demethylation machinery in cellular epigenetic control and further discuss the contribution of methylomic changes and histone modifications to the pathophysiology of AKI.
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Affiliation(s)
- Anubhav Chakraborty
- Renal Research Lab, Centre for Bio-Medical Research, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore 632014, India
| | - Pragasam Viswanathan
- Renal Research Lab, Centre for Bio-Medical Research, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore 632014, India
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17
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Chakraborty A, Viswanathan P. Methylation-Demethylation Dynamics: Implications of Changes in Acute Kidney Injury. Anal Cell Pathol (Amst) 2018; 2018:8764384. [PMID: 30073137 PMCID: PMC6057397 DOI: 10.1155/2018/8764384] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/05/2018] [Accepted: 06/14/2018] [Indexed: 02/05/2023] Open
Abstract
Over the years, the epigenetic landscape has grown increasingly complex. Until recently, methylation of DNA and histones was considered one of the most important epigenetic modifications. However, with the discovery of enzymes involved in the demethylation process, several exciting prospects have emerged that focus on the dynamic regulation of methylation and its crucial role in development and disease. An interplay of the methylation-demethylation machinery controls the process of gene expression. Since acute kidney injury (AKI), a major risk factor for chronic kidney disease and death, is characterised by aberrant expression of genes, understanding the dynamics of methylation and demethylation will provide new insights into the intricacies of the disease. Research on epigenetics in AKI has only made its mark in the recent years but has provided compelling evidence that implicates the involvement of methylation and demethylation changes in its pathophysiology. In this review, we explore the role of methylation and demethylation machinery in cellular epigenetic control and further discuss the contribution of methylomic changes and histone modifications to the pathophysiology of AKI.
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Affiliation(s)
- Anubhav Chakraborty
- Renal Research Lab, Centre for Bio-Medical Research, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore 632014, India
| | - Pragasam Viswanathan
- Renal Research Lab, Centre for Bio-Medical Research, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore 632014, India
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18
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Abstract
The discovery of CpG islands (CGIs) and the study of their structure and properties run parallel to the development of molecular biology in the last two decades of the twentieth century and to the development of high-throughput genomic technologies at the turn of the millennium. First identified as discrete G + C-rich regions of unmethylated DNA in several vertebrates, CGIs were soon found to display additional distinctive chromatin features from the rest of the genome in terms of accessibility and of the epigenetic modifications of their histones. These features, together with their colocalization with promoters and with origins of DNA replication in mammals, highlighted their relevance in the regulation of genomic processes. Recent approaches have shown with unprecedented detail the dynamics and diversity of the epigenetic landscape of CGIs during normal development and under pathological conditions. Also, comparative analyses across species have started revealing how CGIs evolve and contribute to the evolution of the vertebrate genome.
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Affiliation(s)
- Francisco Antequera
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca, Salamanca, Spain.
| | - Adrian Bird
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Edinburgh, EH9 3BF, UK
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19
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Abstract
Recent technological advances have made it possible to decode DNA methylomes at single-base-pair resolution under various physiological conditions. Many aberrant or differentially methylated sites have been discovered, but the mechanisms by which changes in DNA methylation lead to observed phenotypes, such as cancer, remain elusive. The classical view of methylation-mediated protein-DNA interactions is that only proteins with a methyl-CpG binding domain (MBD) can interact with methylated DNA. However, evidence is emerging to suggest that transcription factors lacking a MBD can also interact with methylated DNA. The identification of these proteins and the elucidation of their characteristics and the biological consequences of methylation-dependent transcription factor-DNA interactions are important stepping stones towards a mechanistic understanding of methylation-mediated biological processes, which have crucial implications for human development and disease.
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20
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Edwards JR, Yarychkivska O, Boulard M, Bestor TH. DNA methylation and DNA methyltransferases. Epigenetics Chromatin 2017; 10:23. [PMID: 28503201 PMCID: PMC5422929 DOI: 10.1186/s13072-017-0130-8] [Citation(s) in RCA: 288] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 04/26/2017] [Indexed: 12/18/2022] Open
Abstract
The prevailing views as to the form, function, and regulation of genomic methylation patterns have their origin many years in the past, at a time when the structure of the mammalian genome was only dimly perceived, when the number of protein-encoding mammalian genes was believed to be at least five times greater than the actual number, and when it was not understood that only ~10% of the genome is under selective pressure and likely to have biological function. We use more recent findings from genome biology and whole-genome methylation profiling to provide a reappraisal of the shape of genomic methylation patterns and the nature of the changes that they undergo during gametogenesis and early development. We observe that the sequences that undergo deep changes in methylation status during early development are largely sequences without regulatory function. We also discuss recent findings that begin to explain the remarkable fidelity of maintenance methylation. Rather than a general overview of DNA methylation in mammals (which has been the subject of many reviews), we present a new analysis of the distribution of methylated CpG dinucleotides across the multiple sequence compartments that make up the mammalian genome, and we offer an updated interpretation of the nature of the changes in methylation patterns that occur in germ cells and early embryos. We discuss the cues that might designate specific sequences for demethylation or de novo methylation during development, and we summarize recent findings on mechanisms that maintain methylation patterns in mammalian genomes. We also describe the several human disorders, each very different from the other, that are caused by mutations in DNA methyltransferase genes.
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Affiliation(s)
- John R Edwards
- Center for Pharmacogenomics, Department of Medicine, Washington University School of Medicine, St. Louis, MO USA
| | - Olya Yarychkivska
- Department of Genetics and Development, College of Physicians and Surgeons of Columbia University, New York, NY USA
| | - Mathieu Boulard
- Department of Genetics and Development, College of Physicians and Surgeons of Columbia University, New York, NY USA
| | - Timothy H Bestor
- Department of Genetics and Development, College of Physicians and Surgeons of Columbia University, New York, NY USA
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21
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Features of the interactions between the methyl-CpG motif and the arginine residues on the surface of MBD proteins. Struct Chem 2016. [DOI: 10.1007/s11224-016-0783-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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22
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Lu Z, Lieber MR, Tsai AG, Pardo CE, Müschen M, Kladde MP, Hsieh CL. Human lymphoid translocation fragile zones are hypomethylated and have accessible chromatin. Mol Cell Biol 2015; 35:1209-22. [PMID: 25624348 PMCID: PMC4355534 DOI: 10.1128/mcb.01085-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Revised: 11/26/2014] [Accepted: 01/16/2015] [Indexed: 12/19/2022] Open
Abstract
Chromosomal translocations are a hallmark of hematopoietic malignancies. CG motifs within translocation fragile zones (typically 20 to 600 bp in size) are prone to chromosomal translocation in lymphomas. Here we demonstrate that the CG motifs in human translocation fragile zones are hypomethylated relative to the adjacent DNA. Using a methyltransferase footprinting assay on isolated nuclei (in vitro), we find that the chromatin at these fragile zones is accessible. We also examined in vivo accessibility using cellular expression of a prokaryotic methylase. Based on this assay, which measures accessibility over a much longer time interval than is possible with in vitro methods, these fragile zones were found to be more accessible than the adjacent DNA. Because DNA within the fragile zones can be methylated by both cellular and exogenous methyltransferases, the fragile zones are predominantly in a duplex DNA conformation. These observations permit more-refined models for why these zones are 100- to 1,000-fold more prone to undergo chromosomal translocation than the adjacent regions.
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Affiliation(s)
- Zhengfei Lu
- USC Norris Comprehensive Cancer Ctr., Los Angeles, California, USA
| | - Michael R Lieber
- USC Norris Comprehensive Cancer Ctr., Los Angeles, California, USA
| | - Albert G Tsai
- USC Norris Comprehensive Cancer Ctr., Los Angeles, California, USA
| | - Carolina E Pardo
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Markus Müschen
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Michael P Kladde
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Chih-Lin Hsieh
- USC Norris Comprehensive Cancer Ctr., Los Angeles, California, USA
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23
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Lee KWK, Richmond R, Hu P, French L, Shin J, Bourdon C, Reischl E, Waldenberger M, Zeilinger S, Gaunt T, McArdle W, Ring S, Woodward G, Bouchard L, Gaudet D, Smith GD, Relton C, Paus T, Pausova Z. Prenatal exposure to maternal cigarette smoking and DNA methylation: epigenome-wide association in a discovery sample of adolescents and replication in an independent cohort at birth through 17 years of age. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:193-9. [PMID: 25325234 PMCID: PMC4314251 DOI: 10.1289/ehp.1408614] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Accepted: 10/16/2014] [Indexed: 05/17/2023]
Abstract
BACKGROUND Prenatal exposure to maternal cigarette smoking (prenatal smoke exposure) had been associated with altered DNA methylation (DNAm) at birth. OBJECTIVE We examined whether such alterations are present from birth through adolescence. METHODS We used the Infinium HumanMethylation450K BeadChip to search across 473,395 CpGs for differential DNAm associated with prenatal smoke exposure during adolescence in a discovery cohort (n = 132) and at birth, during childhood, and during adolescence in a replication cohort (n = 447). RESULTS In the discovery cohort, we found five CpGs in MYO1G (top-ranking CpG: cg12803068, p = 3.3 × 10-11) and CNTNAP2 (cg25949550, p = 4.0 × 10-9) to be differentially methylated between exposed and nonexposed individuals during adolescence. The CpGs in MYO1G and CNTNAP2 were associated, respectively, with higher and lower DNAm in exposed versus nonexposed adolescents. The same CpGs were differentially methylated at birth, during childhood, and during adolescence in the replication cohort. In both cohorts and at all developmental time points, the differential DNAm was in the same direction and of a similar magnitude, and was not altered appreciably by adjustment for current smoking by the participants or their parents. In addition, four of the five EWAS (epigenome-wide association study)-significant CpGs in the adolescent discovery cohort were also among the top sites of differential methylation in a previous birth cohort, and differential methylation of CpGs in CYP1A1, AHRR, and GFI1 observed in that study was also evident in our discovery cohort. CONCLUSIONS Our findings suggest that modifications of DNAm associated with prenatal maternal smoking may persist in exposed offspring for many years-at least until adolescence.
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Affiliation(s)
- Ken W K Lee
- The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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Function and information content of DNA methylation. Nature 2015; 517:321-6. [DOI: 10.1038/nature14192] [Citation(s) in RCA: 1327] [Impact Index Per Article: 147.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 11/19/2014] [Indexed: 12/14/2022]
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Abstract
It has been nearly 40 y since it was suggested that genomic methylation patterns could be transmitted via maintenance methylation during S phase and might play a role in the dynamic regulation of gene expression during development [Holliday R, Pugh JE (1975) Science 187(4173):226-232; Riggs AD (1975) Cytogenet Cell Genet 14(1):9-25]. This revolutionary proposal was justified by "... our almost complete ignorance of the mechanism for the unfolding of the genetic program during development" that prevailed at the time. Many correlations between transcriptional activation and demethylation have since been reported, but causation has not been demonstrated and to date there is no reasonable proof of the existence of a complex biochemical system that activates and represses genes via reversible DNA methylation. Such a system would supplement or replace the conserved web of transcription factors that regulate cellular differentiation in organisms that have unmethylated genomes (such as Caenorhaditis elegans and the Dipteran insects) and those that methylate their genomes. DNA methylation does have essential roles in irreversible promoter silencing, as in the monoallelic expression of imprinted genes, in the silencing of transposons, and in X chromosome inactivation in female mammals. Rather than reinforcing or replacing regulatory pathways that are conserved between organisms that have either methylated or unmethylated genomes, DNA methylation endows genomes with the ability to subject specific sequences to irreversible transcriptional silencing even in the presence of all of the factors required for their expression, an ability that is generally unavailable to organisms that have unmethylated genomes.
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Abstract
DNA methylation is the most studied epigenetic modification, capable of controlling gene expression in the contexts of normal traits or diseases. It is highly dynamic during early embryogenesis and remains relatively stable throughout life, and such patterns are intricately related to human development. DNA methylation is a quantitative trait determined by a complex interplay of genetic and environmental factors. Genetic variants at a specific locus can influence both regional and distant DNA methylation. The environment can have varying effects on DNA methylation depending on when the exposure occurs, such as during prenatal life or during adulthood. In particular, cigarette smoking in the context of both current smoking and prenatal exposure is a strong modifier of DNA methylation. Epigenome-wide association studies have uncovered candidate genes associated with cigarette smoking that have biologically relevant functions in the etiology of smoking-related diseases. As such, DNA methylation is a potential mechanistic link between current smoking and cancer, as well as prenatal cigarette-smoke exposure and the development of adult chronic diseases.
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Affiliation(s)
| | - Zdenka Pausova
- Physiology and Experimental Medicine, The Hospital for Sick Children, University of TorontoToronto, ON, Canada
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Okamura E, Matsuzaki H, Sakaguchi R, Takahashi T, Fukamizu A, Tanimoto K. The H19 imprinting control region mediates preimplantation imprinted methylation of nearby sequences in yeast artificial chromosome transgenic mice. Mol Cell Biol 2013; 33:858-71. [PMID: 23230275 PMCID: PMC3571351 DOI: 10.1128/mcb.01003-12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Accepted: 12/06/2012] [Indexed: 12/30/2022] Open
Abstract
In the mouse Igf2/H19 imprinted locus, differential methylation of the imprinting control region (H19 ICR) is established during spermatogenesis and is maintained in offspring throughout development. Previously, however, we observed that the paternal H19 ICR, when analyzed in yeast artificial chromosome transgenic mice (YAC-TgM), was preferentially methylated only after fertilization. To identify the DNA sequences that confer methylation imprinting, we divided the H19 ICR into two fragments (1.7 and 1.2 kb), ligated them to both ends of a λ DNA fragment into which CTCF binding sites had been inserted, and analyzed this in YAC-TgM. The maternally inherited λ sequence, normally methylated after implantation in the absence of H19 ICR sequences, became hypomethylated, demonstrating protective activity against methylation within the ICR. Meanwhile, the paternally inherited λ sequence was hypermethylated before implantation only when a 1.7-kb fragment was ligated. Consistently, when two subfragments of the H19 ICR were individually investigated for their activities in YAC-TgM, only the 1.7-kb fragment was capable of introducing paternal allele-specific DNA methylation. These results show that postfertilization methylation imprinting is conferred by a paternal allele-specific methylation activity present in a 1.7-kb DNA fragment of the H19 ICR, while maternal allele-specific activities protect the allele from de novo DNA methylation.
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Affiliation(s)
- Eiichi Okamura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Hitomi Matsuzaki
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Ryuuta Sakaguchi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takuya Takahashi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Akiyoshi Fukamizu
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Life Science Center of Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Keiji Tanimoto
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Life Science Center of Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan
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De-Castro Arce J, Göckel-Krzikalla E, Rösl F. Silencing of multi-copy HPV16 by viral self-methylation and chromatin occlusion: a model for epigenetic virus-host interaction. Hum Mol Genet 2011; 21:1693-705. [PMID: 22210627 DOI: 10.1093/hmg/ddr604] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In the present study, we used the human papillomavirus type 16 (HPV16)-positive cervical carcinoma cell line CaSki as a paradigmatic model to understand epigenetic silencing of viral multi-copy genomes. We show that most of the hypermethylated HPV16 copies are kept as 'occluded' chromatin that defines a condition where genes were refractory in their response to trans-acting transcription factors and to external reactivation efforts. This provides the first example that viral genomes are silenced by such a host cell mechanism, hitherto only known for endogenous genes to preserve a stable and robust phenotype. Moreover, considering an adaptive cross-talk between viral proteins and the epigenetic modification machinery, we demonstrate that particularly E2-but also ectopically delivered E6/E7-can induce significant de novo methylation within the enhancer and, to a less extent, within the promoter region. These data suggest that under certain physiological conditions, HPV can down-regulate its own gene expression, regardless of the presence of transcriptional activators. We propose that self-methylation of multi-copy HPV could be the first event prior to heterochromatin formation. These processes favour an 'occluded' chromatin conformation, finally being unresponsive to transcriptional activation. The shift from potentially competent heterochromatin towards an occluded state is basically irreversible, possibly using the same mechanism described for lineage differentiation. Along this line, it is tempting to speculate that virus-cell interaction is able to 'sense' viral copy number and down-regulates excess of gene activity in order to guarantee cell viability.
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Affiliation(s)
- Johanna De-Castro Arce
- Division of Viral Transformation Mechanisms, Research Program: Infections and Cancer, Deutsches Krebsforschungszentrum, Heidelberg D-69120, Germany
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Genome-wide conserved consensus transcription factor binding motifs are hyper-methylated. BMC Genomics 2010; 11:519. [PMID: 20875111 PMCID: PMC2997012 DOI: 10.1186/1471-2164-11-519] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Accepted: 09/27/2010] [Indexed: 01/21/2023] Open
Abstract
Background DNA methylation can regulate gene expression by modulating the interaction between DNA and proteins or protein complexes. Conserved consensus motifs exist across the human genome ("predicted transcription factor binding sites": "predicted TFBS") but the large majority of these are proven by chromatin immunoprecipitation and high throughput sequencing (ChIP-seq) not to be biological transcription factor binding sites ("empirical TFBS"). We hypothesize that DNA methylation at conserved consensus motifs prevents promiscuous or disorderly transcription factor binding. Results Using genome-wide methylation maps of the human heart and sperm, we found that all conserved consensus motifs as well as the subset of those that reside outside CpG islands have an aggregate profile of hyper-methylation. In contrast, empirical TFBS with conserved consensus motifs have a profile of hypo-methylation. 40% of empirical TFBS with conserved consensus motifs resided in CpG islands whereas only 7% of all conserved consensus motifs were in CpG islands. Finally we further identified a minority subset of TF whose profiles are either hypo-methylated or neutral at their respective conserved consensus motifs implicating that these TF may be responsible for establishing or maintaining an un-methylated DNA state, or whose binding is not regulated by DNA methylation. Conclusions Our analysis supports the hypothesis that at least for a subset of TF, empirical binding to conserved consensus motifs genome-wide may be controlled by DNA methylation.
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Abstract
Allele-specific DNA methylation (ASM) and allele-specific gene expression (ASE) have long been studied in genomic imprinting and X chromosome inactivation. But these types of allelic asymmetries, along with allele-specific transcription factor binding (ASTF), have turned out to be far more pervasive-affecting many non-imprinted autosomal genes in normal human tissues. ASM, ASE and ASTF have now been mapped genome-wide by microarray-based methods and NextGen sequencing. Multiple studies agree that all three types of allelic asymmetries, as well as the related phenomena of expression and methylation quantitative trait loci, are mostly accounted for by cis-acting regulatory polymorphisms. The precise mechanisms by which this occurs are not yet understood, but there are some testable hypotheses and already a few direct clues. Future challenges include achieving higher resolution maps to locate the epicenters of cis-regulated ASM, using this information to test mechanistic models, and applying genome-wide maps of ASE/ASM/ASTF to pinpoint functional regulatory polymorphisms influencing disease susceptibility.
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Affiliation(s)
- Benjamin Tycko
- Institute for Cancer Genetics and Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University Medical Center, New York, NY 10032, USA.
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31
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Okitsu CY, Hsieh JCF, Hsieh CL. Transcriptional activity affects the H3K4me3 level and distribution in the coding region. Mol Cell Biol 2010; 30:2933-46. [PMID: 20404096 PMCID: PMC2876678 DOI: 10.1128/mcb.01478-09] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 12/29/2009] [Accepted: 04/05/2010] [Indexed: 12/16/2022] Open
Abstract
Histone lysine methylation and CpG DNA methylation contribute to transcriptional regulation. We have shown previously that dimethylated and trimethylated forms of histone H3 at lysine 4 (H3K4me2 and H3K4me3) are primarily depleted from CpG-methylated DNA regions by using patch-methylated stable episomes (minichromosomes) in human cells. This effect on H3K4me2 is clearly not linked to the transcriptional activity in the methylated DNA region; however, transcriptional activity may play a role in the presence of H3K4me3. Here, we present clear evidence of the impact of transcriptional activity on the overall level of H3K4me3 in the coding region and the lack of impact on H3K4me2. Our data also demonstrate the influence of transcriptional activity on the distribution of H3K4me3 and H3K4me2, but not that of total H3, in the 5' end of the coding region relative to the 3' end. The nature of the promoter (viral or endogenous) affects H3K4me3 much more than it affects H3K4me2, suggesting a potential fundamental difference in the recruitment of methyltransferase for H3K4 trimethylation.
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Affiliation(s)
- Cindy Yen Okitsu
- Department of Urology and Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, California
| | - John Cheng Feng Hsieh
- Department of Urology and Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, California
| | - Chih-Lin Hsieh
- Department of Urology and Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, California
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32
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Gebhard C, Benner C, Ehrich M, Schwarzfischer L, Schilling E, Klug M, Dietmaier W, Thiede C, Holler E, Andreesen R, Rehli M. General Transcription Factor Binding at CpG Islands in Normal Cells Correlates with Resistance to De novo DNA Methylation in Cancer Cells. Cancer Res 2010; 70:1398-407. [DOI: 10.1158/0008-5472.can-09-3406] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Ooi SKT, O'Donnell AH, Bestor TH. Mammalian cytosine methylation at a glance. J Cell Sci 2009; 122:2787-91. [PMID: 19657014 DOI: 10.1242/jcs.015123] [Citation(s) in RCA: 198] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Steen K T Ooi
- Department of Genetics and Development, College of Physicians and Surgeons of Columbia University, 701 West 168th Street, New York, NY 10032, USA
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MLL protects CpG clusters from methylation within the Hoxa9 gene, maintaining transcript expression. Proc Natl Acad Sci U S A 2008; 105:7517-22. [PMID: 18483194 DOI: 10.1073/pnas.0800090105] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Homeobox (HOX) genes play a definitive role in determination of cell fate during embryogenesis and hematopoiesis. MLL-related leukemia is coincident with increased expression of a subset of HOX genes, including HOXA9. MLL functions to maintain, rather than initiate, expression of its target genes. However, the mechanism of MLL maintenance of target gene expression is not understood. Here, we demonstrate that Mll binds to specific clusters of CpG residues within the Hoxa9 locus and regulates expression of multiple transcripts. The presence of Mll at these clusters provides protection from DNA methylation. shRNA knock-down of Mll reverses the methylation protection status at the previously protected CpG clusters; methylation at these CpG residues is similar to that observed in Mll null cells. Furthermore, reconstituting MLL expression in Mll null cells can reverse DNA methylation of the same CpG residues, demonstrating a dominant effect of MLL in protecting this specific region from DNA methylation. Intriguingly, an oncogenic MLL-AF4 fusion can also reverse DNA methylation, but only for a subset of these CpGs. This method of transcriptional regulation suggests a mechanism that explains the role of Mll in transcriptional maintenance, but it may extend to other CpG DNA binding proteins. Protection from methylation may be an important mechanism of epigenetic inheritance by regulating the function of both de novo and maintenance DNA methyltransferases.
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De-Castro Arce J, Göckel-Krzikalla E, Rösl F. Retinoic acid receptor beta silences human papillomavirus-18 oncogene expression by induction of de novo methylation and heterochromatinization of the viral control region. J Biol Chem 2007; 282:28520-28529. [PMID: 17686773 DOI: 10.1074/jbc.m702870200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Retinoic acid receptor beta2 (RAR beta2) is often down-regulated during the multistep process to cervical cancer. In that way, its inhibitory function on the transcription factor AP-1, indispensable to maintain human papillomavirus (HPV) gene expression is relieved. Using HPV-18 positive HeLa cells as a model system, we show that ectopic expression of RAR beta2 is able to down-regulate HPV-18 transcription by selectively abrogating the binding of AP-1 to the viral regulatory region in a ligand-independent manner. This resulted in down-regulation of the viral mRNAs at the level of initiation of transcription. Decreased oncogene expression was accompanied by a re-induction of cell cycle inhibitory proteins such as p53, p21(CIP1), and p27(KIP) as well as by a cessation of cellular growth. Reduced transcriptional activity as a consequence of AP-1 reduction by selective c-Jun degradation apparently targets the HPV-18 regulatory region for epigenetic modification such as de novo methylation and nucleosomal condensation. This mechanism is otherwise counterbalanced by active and abundant viral transcription in malignant cells, because RAR beta2 itself becomes inactivated during cervical carcinogenesis. Hence, our study shows that the temporal co-existence of a potential repressor and viral oncoproteins is mutually exclusive and provides evidence of a cross-talk between a nuclear receptor, AP-1, and the epigenetic machinery.
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Affiliation(s)
- Johanna De-Castro Arce
- Angewandte Tumorvirologie, Abteilung Virale Transformationsmechanismen, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany
| | - Elke Göckel-Krzikalla
- Angewandte Tumorvirologie, Abteilung Virale Transformationsmechanismen, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany
| | - Frank Rösl
- Angewandte Tumorvirologie, Abteilung Virale Transformationsmechanismen, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.
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Singh M, Lavelle D, Vaitkus K, Mahmud N, Hankewych M, DeSimone J. The gamma-globin gene promoter progressively demethylates as the hematopoietic stem progenitor cells differentiate along the erythroid lineage in baboon fetal liver and adult bone marrow. Exp Hematol 2007; 35:48-55. [PMID: 17198873 DOI: 10.1016/j.exphem.2006.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Revised: 09/01/2006] [Accepted: 09/05/2006] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To determine whether the difference in gamma-globin gene promoter methylation in terminal erythroblasts at the fetal and adult stages of development is a result of fetal stage-specific demethylation or adult stage-specific de novo methylation during erythropoiesis. MATERIALS AND METHODS Fetal liver- (FL, n = 2) and adult bone marrow- (ABM, n = 3) derived hematopoietic stem/progenitor cells and mature erythroblasts were purified by passage through a Miltenyi Magnetic Column followed by fluorescein-activated cell sorting (FACS) into subpopulations, defined by expression of CD34 and CD36 antigens. CD34(+)CD36(-), CD34(+)CD36(+), and CD34(-)CD36(+) subpopulations were purified by FACS and their degree of differentiation verified using the colony-forming cell assay. The methylation pattern of 5 CpG sites in the gamma-globin promoter region of these purified cell populations was determined using bisulfite sequencing. RESULTS The gamma-globin promoter was highly methylated in the earliest stage of hematopoietic stem progenitor cells (CD34(+)CD36(-)) and methylation progressively decreased as erythroid differentiation progressed in FL and appears so in ABM as well. CONCLUSIONS These data support a model in which differences in the methylation pattern of the gamma-globin gene in differentiating erythroblasts at different stages of development is the result of fetal stage-specific demethylation associated with transcriptional activation, rather than de novo methylation in the adults. The difference in the extent of gamma-globin gene demethylation in FL and ABM is correlated with the difference in gamma-globin expression at these developmental stages.
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Affiliation(s)
- Mahipal Singh
- Jesse Brown VA Medical Center, Chicago, IL 60612, USA.
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Kameda T, Smuga-Otto K, Thomson JA. A severe de novo methylation of episomal vectors by human ES cells. Biochem Biophys Res Commun 2006; 349:1269-77. [PMID: 16973130 DOI: 10.1016/j.bbrc.2006.08.175] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Accepted: 08/29/2006] [Indexed: 11/29/2022]
Abstract
Episomal vectors can allow efficient genetic modification of cells and have the potential advantage of avoiding chromosomal position of integration effects. Here we explore the use of an Epstein-Barr virus-based episomal vector with human embryonic stem (ES) cells, and find high initial transfection rates, but a rapid loss of reporter gene expression. Similar to mouse ES cells, human ES cells express high levels of the de novo DNA methyltransferases, and we detected dramatic CpG methylation and minor non-CpG methylation on the episomes recovered from the human ES cells 7 days after the transfection, which was not present on the same episome recovered from 293 cells. Interestingly, the oriP region of the episomes was relatively excluded from this methylation. These findings define some of the limitations of using episomal vectors with human ES cells and offer a unique platform for analyzing epigenetic gene silencing in human ES cells.
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Affiliation(s)
- Takashi Kameda
- The Genome Center of Wisconsin, University of Wisconsin-Madison, 53706, USA
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38
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Chen ZX, Riggs AD. Maintenance and regulation of DNA methylation patterns in mammals. Biochem Cell Biol 2005; 83:438-48. [PMID: 16094447 DOI: 10.1139/o05-138] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Proper establishment and faithful maintenance of epigenetic information is crucial for the correct development of complex organisms. For mammals, it is now accepted that DNA methylation is an important mechanism for establishing stable heritable epigenetic marks. The distribution of methylation in the genome is not random, and patterns of methylated and unmethylated DNA are well regulated during normal development. The molecular mechanisms by which methylation patterns are established and maintained are complex and just beginning to be understood. In this review, we summarize recent progress in understanding the regulation of mammalian DNA methylation patterns, with an emphasis on the emerging roles of several protein and possible RNA factors. We also revisit the stochastic model of maintenance methylation and discuss its implications for epigenetic fidelity and gene regulation.
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Affiliation(s)
- Zhao-xia Chen
- Division of Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
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Abstract
Abstract
The unmethylated or methylated status of individual CpG sites is faithfully copied into daughter cells. Here, we analyzed the fidelity in replicating their methylation statuses in cancer cells. A single cell was clonally expanded, and methylation statuses of individual CpG sites were determined for an average of 12.5 DNA molecules obtained from the expanded population. By counting the deviation from the original methylation patterns inferred, the number of errors was measured. The analysis was done in four gastric cancer cell lines for five CpG islands (CGI), and repeated six times (total 1,495 clones sequenced). HSC39 and HSC57 showed error rates <1.0 × 10−3 errors per site per generation (99.90-100% fidelity) for all the five CGIs. In contrast, AGS showed significantly elevated error rates, mainly due to increased de novo methylation, in three CGIs (1.6- to 3.2-fold), and KATOIII showed a significantly elevated error rate in one CGI (2.2-fold). By selective amplification of fully methylated DNA molecules by methylation-specific PCR, those were stochastically detected in KATOIII and AGS but never in HSC39 and HSC57. When methylation of entire CGIs was examined for eight additional CGIs, KATOIII and AGS had frequent methylation, whereas HSC39 and HSC57 had few. KATOIII and AGS had four and eight times, respectively, as high expression levels of DNMT3B as HSC39. These data showed that some cancer cells have decreased fidelity in replicating methylation patterns in some CGIs, and that the decrease could lead to methylation of the entire CGIs.
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40
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Riggs AD. X chromosome inactivation, differentiation, and DNA methylation revisited, with a tribute to Susumu Ohno. Cytogenet Genome Res 2004; 99:17-24. [PMID: 12900540 DOI: 10.1159/000071569] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2002] [Accepted: 01/27/2003] [Indexed: 11/19/2022] Open
Abstract
X chromosome inactivation and DNA methylation are reviewed, with emphasis on the contributions of Susumu Ohno and the predictions made in my 1975 paper (Riggs, 1975), in which I proposed the "maintenance methylase" model for somatic inheritance of methylation patterns and suggested that DNA methylation would be involved in mammalian X chromosome inactivation and development. The maintenance methylase model is discussed and updated to consider methylation patterns in cell populations that have occasional, stochastic methylation changes by de novo methylation or demethylation, either active or passive. The "way station" model for the spread of X inactivation by LINE-1 elements is also considered, and some recent results from my laboratory are briefly reviewed.
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Affiliation(s)
- A D Riggs
- Department of Biology, Beckman Research Institute of The City of Hope National Medical Center, Duarte, CA 91010, USA.
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41
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Affiliation(s)
- Arthur D Riggs
- Division of Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
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42
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Levine JJ, Stimson-Crider KM, Vertino PM. Effects of methylation on expression of TMS1/ASC in human breast cancer cells. Oncogene 2003; 22:3475-88. [PMID: 12776200 DOI: 10.1038/sj.onc.1206430] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Gene silencing associated with aberrant methylation of promoter region CpG islands is one mechanism in which tumor suppressor genes are inactivated in human cancers. Recently, we identified a novel gene, Target of Methylation-associated Silencing-1 (TMS1) (also called ASC), which is aberrantly methylated and silenced in human breast cancers. To further investigate the mechanism of TMS1 silencing, we defined the transcription initiation site and detailed the DNA methylation pattern of the TMS1 CpG island in normal breast epithelial cells, breast cancer cell lines, and primary tumors. We find that in normal cells, the TMS1 CpG island lies within a 1.2 kb unmethylated domain, the 5' boundary of which is in close proximity to the transcription initiation site. In breast cancer cell lines, this boundary appeared to be unstable in that methylation tended to accumulate in the 5' end of the CpG island relative to normal epithelial cells. In contrast, the 3' methylation boundary remained intact. Gene silencing was not correlated with the methylation of specific CpG sites nor the inability to transactivate the TMS1 promoter, but was correlated with the percentage of alleles in the population exhibiting dense methylation across the entire CpG island. Using 5-aza-deoxycytidine to reactivate TMS1 in methylated and silent cell lines, and a cassette methylation strategy to determine the impact of methylation on different parts of the promoter, we find that demethylation of a small region immediately surrounding the transcription start site is critical to TMS1 expression. Our data support the idea that gene silencing and dense methylation are tightly coupled events that affect individual chromosomal copies of TMS1 in an all-or-none manner. The transition to this stably repressed state may be facilitated by spreading of methylation into the proximal promoter and direct effects of methylation on TMS1 transcription.
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Affiliation(s)
- Jeoffrey J Levine
- Program in Genetics and Molecular Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
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Ushijima T, Watanabe N, Okochi E, Kaneda A, Sugimura T, Miyamoto K. Fidelity of the methylation pattern and its variation in the genome. Genome Res 2003; 13:868-74. [PMID: 12727906 PMCID: PMC430912 DOI: 10.1101/gr.969603] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2002] [Accepted: 02/26/2003] [Indexed: 12/31/2022]
Abstract
The methylated or unmethylated status of a CpG site is copied faithfully from parental DNA to daughter DNA, and functions as a cellular memory. However, no information is available for the fidelity of methylation pattern in unmethylated CpG islands (CGIs) or its variation in the genome. Here, we determined the methylation status of each CpG site on each DNA molecule obtained from clonal populations of normal human mammary epithelial cells. Methylation pattern error rates (MPERs) were calculated based upon the deviation from the methylation patterns that should be obtained if the cells had 100% fidelity in replicating the methylation pattern. Unmethylated CGIs in the promoter regions of five genes showed MPERs of 0.018-0.032 errors/site/21.6 generations, and the fidelity of methylation pattern was calculated as 99.85%-99.92%/site/generation. In contrast, unmethylated CGIs outside the promoter regions showed MPERs more than twice as high (P < 0.01). Methylated regions, including a CGI in the MAGE-A3 promoter and DMR of the H19 gene, showed much lower MPERs than unmethylated CGIs. These showed that errors in methylation pattern were mainly due to de novo methylations in unmethylated regions. The differential MPERs even among unmethylated CGIs indicated that a promoter-specific protection mechanism(s) from de novo methylation was present.
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Affiliation(s)
- Toshikazu Ushijima
- Carcinogenesis Division, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan.
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Quong J, Eppenberger-Castori S, Moore D, Scott GK, Birrer MJ, Kueng W, Eppenberger U, Benz CC. Age-dependent changes in breast cancer hormone receptors and oxidant stress markers. Breast Cancer Res Treat 2002; 76:221-36. [PMID: 12462383 DOI: 10.1023/a:1020886801674] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Breast cancer incidence increases with age but this relationship has not been fully explored with regard to expression of estrogen receptor (ER) and ER-inducible genes (PR, pS2, Bcl2, cathepsin D), or the age-dependence of oxidant stress markers that also affect ER-inducible gene expression. In this three-part study, we first correlated age at diagnosis with expression of breast cancer markers ER, PR, pS2, Bcl2, and cathepsin D, quantitated by enzyme immunoassays from a European collective of approximately 3000 cryobanked primary breast cancers and approximately 300 adjacent non-malignant breast tissues. Results were then compared with ER and PR data reported to the SEER registry for 83,541 US cancers diagnosed during 1992-1997. Lastly, a homogeneous subset of 70 ER-positive tumors preselected from the European collective was blindly analyzed for age-specific changes in the DNA-binding content of redox-sensitive transcriprtion factors, AP1 and Sp1, and the oxidant stress-activated protein kinase, phosphorylated(P)-Erk5. Increases in breast tumor ER from patients aged <30 to >80 years mirrored 10-fold lower increases in non-malignant breast tissue ER content up to age 60, rising faster thereafter and reaching a near 25-fold differential between malignant and non-malignant breast tissue by age 80. ER-inducible markers PR, pS2, Bcl2, and cathepsin D were overexpressed in tumors relative to non-malignant breast tissue but, unlike ER, did not increase with patient age. While SEER data demonstrated that the increase in US breast cancer incidence rates after age 50 is confined to ER-positive tumors in patients of all ethnic subsets, these patients also showed a striking increase in the proportion of higher-risk ER-positive/PR-negative breast cancers arising after age 50. Mechanistically essential for ER-inducible PR expression, Sp1 DNA-binding function (but not Sp1 content) was lost with age in ER-positive tumors; and this functional defect correlated with increased tumor content of the oxidant stress marker, P-Erk5. Altogether these findings support two hypotheses: (i) dysregulated ER expression underlies the age-specific increase in breast cancer incidence after age 50; and (ii) oxidative stress and loss of Sp1 DNA-binding may contribute to an increasing incidence in higher-risk ER-positive/PR-negative breast cancers with aging.
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Affiliation(s)
- Judy Quong
- Comprehensive Cancer Center, University of California, San Francisco, CA, USA
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Gidekel S, Bergman Y. A unique developmental pattern of Oct-3/4 DNA methylation is controlled by a cis-demodification element. J Biol Chem 2002; 277:34521-30. [PMID: 12110668 DOI: 10.1074/jbc.m203338200] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Oct-3/4 is the earliest expressed transcription factor that is known to be crucial in murine pre-implantation development. In this report we asked whether methylation participates in controlling changes in Oct-3/4 expression and thus may play an important role in controlling normal embryogenesis. We show that the Oct-3/4 gene is unmethylated from the blastula stage but undergoes de novo methylation at 6.5 days post-coitum and remains modified in all adult somatic tissues analyzed. Oct-3/4 remains unmethylated in 6.25 days post-coitum epiblast cells when other genes, such as apoAI, undergo de novo methylation. We show that methylation of the Oct-3/4 promoter sequence strongly compromises its ability to direct efficient transcription. Moreover, DNA methylation inhibits basal transcription of the endogenous Oct-3/4 gene in vivo. We found that the Oct-3/4 gene harbors a cis-specific demodification element that includes the proximal enhancer sequence. This element leads to demethylation in embryonal carcinoma cells when the sequence is initially methylated and protects the local region from de novo methylation in post-implantation embryos. These results indicate that in the embryo protection from de novo methylation is not a unique feature of imprinted or housekeeping genes that carry a CpG island, but is also applicable to tissue-specific genes expressed during early stages of embryogenesis. Methylation of Oct-3/4 may be analogous to methylation of CpG islands on the inactive X chromosome that also occurs at later stages of development.
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Affiliation(s)
- Sharon Gidekel
- Department of Experimental Medicine and Cancer Research, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
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Abstract
DNA methyltransferases catalyze the transfer of a methyl group from S-adenosyl-L-methionine to cytosine or adenine bases in DNA. These enzymes challenge the Watson/Crick dogma in two instances: 1) They attach inheritable information to the DNA that is not encoded in the nucleotide sequence. This so-called epigenetic information has many important biological functions. In prokaryotes, DNA methylation is used to coordinate DNA replication and the cell cycle, to direct postreplicative mismatch repair, and to distinguish self and nonself DNA. In eukaryotes, DNA methylation contributes to the control of gene expression, the protection of the genome against selfish DNA, maintenance of genome integrity, parental imprinting, X-chromosome inactivation in mammals, and regulation of development. 2) The enzymatic mechanism of DNA methyltransferases is unusual, because these enzymes flip their target base out of the DNA helix and, thereby, locally disrupt the B-DNA helix. This review describes the biological functions of DNA methylation in bacteria, fungi, plants, and mammals. In addition, the structures and mechanisms of the DNA methyltransferases, which enable them to specifically recognize their DNA targets and to induce such large conformational changes of the DNA, are discussed.
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Affiliation(s)
- Albert Jeltsch
- Institut für Biochemie, FB 8, Justus-Liebig-Universität, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
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Chen Y, Sharma RP, Costa RH, Costa E, Grayson DR. On the epigenetic regulation of the human reelin promoter. Nucleic Acids Res 2002; 30:2930-9. [PMID: 12087179 PMCID: PMC117056 DOI: 10.1093/nar/gkf401] [Citation(s) in RCA: 187] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Reln mRNA and protein levels are reduced by approximately 50% in various cortical structures of post-mortem brain from patients diagnosed with schizophrenia or bipolar illness with psychosis. To study mechanisms responsible for this down-regulation, we have analyzed the promoter of the human reelin gene. We show that the reelin promoter directs expression of a reporter construct in multiple human cell types: neuroblastoma cells (SHSY5Y), neuronal precursor cells (NT2), differentiated neurons (hNT) and hepatoma cells (HepG2). Deletion constructs confirmed the presence of multiple elements regulating Reln expression, although the promoter activity is promiscuous, i.e. activity did not correlate with expression of the endogenous gene as reflected in terms of reelin mRNA levels. Co-transfection of the -514 bp human reelin promoter with either Sp1 or Tbr1 demonstrated that these transcription factors activate reporter expression by 6- and 8.5-fold, respectively. Within 400 bp of the RNA start site there are 100 potential CpG targets for DNA methylation. Retinoic acid (RA)-induced differentiation of NT2 cells to hNT neurons was accompanied by increased reelin expression and by the appearance of three DNase I hypersensitive sites 5' to the RNA start site. RA-induced differentiation was also associated with demethylation of the reelin promoter. To test if methylation silenced reelin expression, we methylated the promoter in vitro prior to transfection. In addition, we treated NT2 cells with the methylation inhibitor aza-2'-deoxycytidine and observed a 60-fold increase in reelin mRNA levels. The histone deacetylase inhibitors trichostatin A (TSA) and valproic acid also induced expression of the endogenous reelin promoter, although TSA was considerably more potent. These findings indicate that one determinant responsible for regulating reelin expression is the methylation status of the promoter. Our data also raise the interesting possibility that the down-regulation of reelin expression documented in psychiatric patients might be the consequence of inappropriate promoter hypermethylation.
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Affiliation(s)
- Ying Chen
- Psychiatric Institute, Department of Psychiatry, 1601 West Taylor Street, M/C 912, College of Medicine, University of Illinois, Chicago, IL 60612, USA
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Mutskov VJ, Farrell CM, Wade PA, Wolffe AP, Felsenfeld G. The barrier function of an insulator couples high histone acetylation levels with specific protection of promoter DNA from methylation. Genes Dev 2002; 16:1540-54. [PMID: 12080092 PMCID: PMC186352 DOI: 10.1101/gad.988502] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2002] [Accepted: 05/01/2002] [Indexed: 11/25/2022]
Abstract
Stably integrated transgenes flanked by the chicken beta-globin HS4 insulator are protected against chromosomal position effects and gradual extinction of expression during long-term propagation in culture. To investigate the mechanism of action of this insulator, we used bisulfite genomic sequencing to examine the methylation of individual CpG sites within insulated transgenes, and compared this with patterns of histone acetylation. Surprisingly, although the histones of the entire insulated transgene are highly acetylated, only a specific region in the promoter, containing binding sites for erythroid-specific transcription factors, is highly protected from DNA methylation. This critical region is methylated in noninsulated and inactive lines. MBD3 and Mi-2, subunits of the Mi-2/NuRD repressor complex, are bound in vivo to these silenced noninsulated transgenes. In contrast, insulated cell lines do not show any enrichment of Mi-2/NuRD proteins very late in culture. In addition to the high levels of histone acetylation observed across the entire insulated transgene, significant peaks of H3 acetylation are present over the HS4 insulator elements. Targeted histone acetylation by the chicken beta-globin insulator occurs independently of gene transcription and does not require the presence of a functional enhancer. We suggest that this acetylation is in turn responsible for the maintenance of a region of unmethylated DNA over the promoter. Whereas DNA methylation often leads to histone deacetylation, here acetylation appears to prevent methylation.
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Affiliation(s)
- Vesco J Mutskov
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA
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Abstract
DNA methyltransferases catalyze the transfer of a methyl group from S-adenosyl-L-methionine to cytosine or adenine bases in DNA. These enzymes challenge the Watson/Crick dogma in two instances: 1) They attach inheritable information to the DNA that is not encoded in the nucleotide sequence. This so-called epigenetic information has many important biological functions. In prokaryotes, DNA methylation is used to coordinate DNA replication and the cell cycle, to direct postreplicative mismatch repair, and to distinguish self and nonself DNA. In eukaryotes, DNA methylation contributes to the control of gene expression, the protection of the genome against selfish DNA, maintenance of genome integrity, parental imprinting, X-chromosome inactivation in mammals, and regulation of development. 2) The enzymatic mechanism of DNA methyltransferases is unusual, because these enzymes flip their target base out of the DNA helix and, thereby, locally disrupt the B-DNA helix. This review describes the biological functions of DNA methylation in bacteria, fungi, plants, and mammals. In addition, the structures and mechanisms of the DNA methyltransferases, which enable them to specifically recognize their DNA targets and to induce such large conformational changes of the DNA, are discussed.
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Affiliation(s)
- Albert Jeltsch
- Institut für Biochemie, FB 8, Justus-Liebig-Universität, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
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Stimson KM, Vertino PM. Methylation-mediated silencing of TMS1/ASC is accompanied by histone hypoacetylation and CpG island-localized changes in chromatin architecture. J Biol Chem 2002; 277:4951-8. [PMID: 11733524 DOI: 10.1074/jbc.m109809200] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aberrant methylation of CpG-dense islands in the promoter regions of genes is an acquired epigenetic alteration associated with the silencing of tumor suppressor genes in human cancers. In a screen for endogenous targets of methylation-mediated gene silencing, we identified a novel CpG island-associated gene, TMS1, which is aberrantly methylated and silenced in response to the ectopic expression of DNA methyltransferase-1. TMS1 functions in the regulation of apoptosis and is frequently methylated and silenced in human breast cancers. In this study, we characterized the methylation pattern and chromatin architecture of the TMS1 locus in normal fibroblasts and determined the changes associated with its progressive methylation. In normal fibroblasts expressing TMS1, the CpG island is defined by an unmethylated domain that is separated from densely methylated flanking DNA by distinct 5' and 3' boundaries. Analysis of the nucleoprotein architecture of the locus in intact nuclei revealed three DNase I-hypersensitive sites that map within the CpG island. Strikingly, two of these sites coincided with the 5'- and 3'-methylation boundaries. Methylation of the TMS1 CpG island was accompanied by loss of hypersensitive site formation, hypoacetylation of histones H3 and H4, and gene silencing. This altered chromatin structure was confined to the CpG island and occurred without significant changes in methylation, histone acetylation, or hypersensitive site formation at a fourth DNase I-hypersensitive site 2 kb downstream of the TMS1 CpG island. The data indicate that there are sites of protein binding and/or structural transitions that define the boundaries of the unmethylated CpG island in normal cells and that aberrant methylation overcomes these boundaries to direct a local change in chromatin structure, resulting in gene silencing.
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Affiliation(s)
- Krista M Stimson
- Department of Radiation Oncology and the Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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