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Murray KO, Brant JO, Spradlin RA, Thome T, Laitano O, Ryan TE, Riva A, Kladde MP, Clanton TL. Exertional heat stroke causes long-term skeletal muscle epigenetic reprogramming, altered gene expression, and impaired satellite cell function in mice. Am J Physiol Regul Integr Comp Physiol 2024; 326:R160-R175. [PMID: 38047316 PMCID: PMC11283893 DOI: 10.1152/ajpregu.00226.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/26/2023] [Accepted: 11/26/2023] [Indexed: 12/05/2023]
Abstract
The effect of exertional heat stroke (EHS) exposure on skeletal muscles is incompletely understood. Muscle weakness is an early symptom of EHS but is not considered a major target of multiorgan injury. Previously, in a preclinical mouse model of EHS, we observed the vulnerability of limb muscles to a second EHS exposure, suggesting hidden processes contributing to declines in muscle resilience. Here, we evaluated the possible molecular origins of EHS-induced declines in muscle resilience. Female C57BL/6 mice [total n = 56; 28/condition, i.e., EHS and exercise control (EXC)] underwent forced wheel running at 37.5°C/40% relative humidity until symptom limitation (unconsciousness). EXC mice exercised identically at room temperature (22-23°C). After 1 mo of recovery, the following were assessed: 1) specific force and caffeine-induced contracture in soleus (SOL) and extensor digitorum longus (EDL) muscles; 2) transcriptome and DNA methylome responses in gastrocnemius (GAST); and 3) primary satellite cell function (proliferation and differentiation). There were no differences in specific force in either SOL or EDL from EXC. Only EHS solei exhibited lower caffeine sensitivity. EHS GAST exhibited higher RNA expression of genes encoding structural proteins of slow fibers, heat shock proteins, and myogenesis. A total of ∼2,500 differentially methylated regions of DNA that could potentially affect many cell functions were identified. Primary satellite cells exhibited suppressed proliferation rates but normal differentiation responses. Results demonstrate long-term changes in skeletal muscles 1 mo after EHS that could contribute to declines in muscle resilience. Skeletal muscle may join other, more recognized tissues considered vulnerable to long-term effects of EHS.NEW & NOTEWORTHY Exertional heat stroke (EHS) in mice induces long-term molecular and functional changes in limb muscle that could reflect a loss of "resilience" to further stress. The phenotype was characterized by altered caffeine sensitivity and suppressed satellite cell proliferative potential. This was accompanied by changes in gene expression and DNA methylation consistent with ongoing muscle remodeling and stress adaptation. We propose that EHS may induce a prolonged vulnerability of skeletal muscle to further stress or injury.
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Affiliation(s)
- Kevin O Murray
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, United States
| | - Jason O Brant
- Department of Biostatistics, University of Florida, Gainesville, Florida, United States
- University of Florida Health Cancer Center, University of Florida, Gainesville, Florida, United States
| | - Ray A Spradlin
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, United States
| | - Trace Thome
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, United States
| | - Orlando Laitano
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, United States
| | - Terence E Ryan
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, United States
| | - Alberto Riva
- University of Florida Health Cancer Center, University of Florida, Gainesville, Florida, United States
- Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, Florida, United States
| | - Michael P Kladde
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, Florida, United States
- University of Florida Health Cancer Center, University of Florida, Gainesville, Florida, United States
| | - Thomas L Clanton
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, United States
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2
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Epigenetic regulation of fetal brain development in pig. Gene 2022; 844:146823. [PMID: 35988784 DOI: 10.1016/j.gene.2022.146823] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 07/27/2022] [Accepted: 08/15/2022] [Indexed: 02/01/2023]
Abstract
How fetal brain development is regulated at the molecular level is not well understood. Due to ethical challenges associated with research on the human fetus, large animals particularly pigs are increasingly used to study development and disorders of fetal brain. The pig fetal brain grows rapidly during the last ∼ 50 days before birth which is around day 60 (d60) of pig gestation. But what regulates the onset of accelerated growth of the brain is unknown. The current study tests the hypothesis that epigenetic alteration around d60 is involved in the onset of rapid growth of fetal brain of pig. To test this hypothesis, DNA methylation changes of fetal brain was assessed in a genome-wide manner by Enzymatic Methyl-seq (EM-seq) during two gestational periods (GP): d45 vs. d60 (GP1) and d60 vs. d90 (GP2). The cytosine-guanine (CpG) methylation data was analyzed in an integrative manner with the RNA-seq data generated from the same brain samples from our earlier study. A neural network based modeling approach was implemented to learn changes in methylation patterns of the differentially expressed genes, and then predict methylations of the brain in a genome-wide manner during rapid growth. This approach identified specific methylations that changed in a mutually informative manner during rapid growth of the fetal brain. These methylations were significantly overrepresented in specific genic as well as intergenic features including CpG islands, introns, and untranslated regions. In addition, sex-bias methylations of known single nucleotide polymorphic sites were also identified in the fetal brain ide during rapid growth.
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Islam M, Strawn M, Behura SK. Fetal origin of sex‐bias brain aging. FASEB J 2022; 36:e22463. [DOI: 10.1096/fj.202200255rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 06/30/2022] [Accepted: 07/11/2022] [Indexed: 02/01/2023]
Affiliation(s)
- Maliha Islam
- Division of Animal Sciences University of Missouri Columbia Missouri USA
| | - Monica Strawn
- Division of Animal Sciences University of Missouri Columbia Missouri USA
| | - Susanta K. Behura
- Division of Animal Sciences University of Missouri Columbia Missouri USA
- MU Institute for Data Science and Informatics University of Missouri Columbia Missouri USA
- Interdisciplinary Neuroscience Program University of Missouri Columbia Missouri USA
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4
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Zhang Z, Xu J, Lyu S, Xin X, Shi Q, Huang Y, Yu X, Zhu X, Li Z, Wang X, Lang L, Xu Z, Wang E. Whole-Genome DNA Methylation Dynamics of Sheep Preimplantation Embryo Investigated by Single-Cell DNA Methylome Sequencing. Front Genet 2021; 12:753144. [PMID: 35003207 PMCID: PMC8733409 DOI: 10.3389/fgene.2021.753144] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 11/01/2021] [Indexed: 11/13/2022] Open
Abstract
The early stages of mammalian embryonic development involve the participation and cooperation of numerous complex processes, including nutritional, genetic, and epigenetic mechanisms. However, in embryos cultured in vitro, a developmental block occurs that affects embryo development and the efficiency of culture. Although the block period is reported to involve the transcriptional repression of maternal genes and transcriptional activation of zygotic genes, how epigenetic factors regulate developmental block is still unclear. In this study, we systematically analyzed whole-genome methylation levels during five stages of sheep oocyte and preimplantation embryo development using single-cell level whole genome bisulphite sequencing (SC-WGBS) technology. Then, we examined several million CpG sites in individual cells at each evaluated developmental stage to identify the methylation changes that take place during the development of sheep preimplantation embryos. Our results showed that two strong waves of methylation changes occurred, namely, demethylation at the 8-cell to 16-cell stage and methylation at the 16-cell to 32-cell stage. Analysis of DNA methylation patterns in different functional regions revealed a stable hypermethylation status in 3'UTRs and gene bodies; however, significant differences were observed in intergenic and promoter regions at different developmental stages. Changes in methylation at different stages of preimplantation embryo development were also compared to investigate the molecular mechanisms involved in sheep embryo development at the methylation level. In conclusion, we report a detailed analysis of the DNA methylation dynamics during the development of sheep preimplantation embryos. Our results provide an explanation for the complex regulatory mechanisms underlying the embryo developmental block based on changes in DNA methylation levels.
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Affiliation(s)
- Zijing Zhang
- Institute of Animal Husbandry and Veterinary Science, Henan Academy of Agricultural Sciences, Zhengzhou, China
| | - Jiawei Xu
- College of Animal Science and Technology, Northwest A & F University, Yangling, China
| | - Shijie Lyu
- Institute of Animal Husbandry and Veterinary Science, Henan Academy of Agricultural Sciences, Zhengzhou, China
| | - Xiaoling Xin
- Institute of Animal Husbandry and Veterinary Science, Henan Academy of Agricultural Sciences, Zhengzhou, China
| | - Qiaoting Shi
- Institute of Animal Husbandry and Veterinary Science, Henan Academy of Agricultural Sciences, Zhengzhou, China
| | - Yongzhen Huang
- College of Animal Science and Technology, Northwest A & F University, Yangling, China
| | - Xiang Yu
- Animal Health Supervision Institute of Henan Province, Zhengzhou, China
| | - Xiaoting Zhu
- Institute of Animal Husbandry and Veterinary Science, Henan Academy of Agricultural Sciences, Zhengzhou, China
| | - Zhiming Li
- Henan Provincial Animal Husbandry General Station, Zhengzhou, China
| | - Xianwei Wang
- Henan Provincial Animal Husbandry General Station, Zhengzhou, China
| | - Limin Lang
- Institute of Animal Husbandry and Veterinary Science, Henan Academy of Agricultural Sciences, Zhengzhou, China
| | - Zhaoxue Xu
- Institute of Animal Husbandry and Veterinary Science, Henan Academy of Agricultural Sciences, Zhengzhou, China
| | - Eryao Wang
- Institute of Animal Husbandry and Veterinary Science, Henan Academy of Agricultural Sciences, Zhengzhou, China
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Sepers B, Erven JAM, Gawehns F, Laine VN, van Oers K. Epigenetics and Early Life Stress: Experimental Brood Size Affects DNA Methylation in Great Tits (Parus major). Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.609061] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Early developmental conditions are known to have life-long effects on an individual’s behavior, physiology and fitness. In altricial birds, a majority of these conditions, such as the number of siblings and the amount of food provisioned, are controlled by the parents. This opens up the potential for parents to adjust the behavior and physiology of their offspring according to local post-natal circumstances. However, the mechanisms underlying such intergenerational regulation remain largely unknown. A mechanism often proposed to possibly explain how parental effects mediate consistent phenotypic change is DNA methylation. To investigate whether early life effects on offspring phenotypes are mediated by DNA methylation, we cross-fostered great tit (Parus major) nestlings and manipulated their brood size in a natural study population. We assessed genome-wide DNA methylation levels of CpG sites in erythrocyte DNA, using Reduced Representation Bisulfite Sequencing (RRBS). By comparing DNA methylation levels between biological siblings raised in enlarged and reduced broods and between biological siblings of control broods, we assessed which CpG sites were differentially methylated due to brood size. We found 32 differentially methylated sites (DMS) between siblings from enlarged and reduced broods, a larger number than in the comparison between siblings from control broods. A considerable number of these DMS were located in or near genes involved in development, growth, metabolism, behavior and cognition. Since the biological functions of these genes line up with previously found effects of brood size and food availability, it is likely that the nestlings in the enlarged broods suffered from nutritional stress. We therefore conclude that early life stress might directly affect epigenetic regulation of genes related to early life conditions. Future studies should link such experimentally induced DNA methylation changes to expression of phenotypic traits and assess whether these effects affect parental fitness to determine if such changes are also adaptive.
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Dong W, Yang J, Zhang Y, Liu S, Ning C, Ding X, Wang W, Zhang Y, Zhang Q, Jiang L. Integrative analysis of genome-wide DNA methylation and gene expression profiles reveals important epigenetic genes related to milk production traits in dairy cattle. J Anim Breed Genet 2021; 138:562-573. [PMID: 33620112 DOI: 10.1111/jbg.12530] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 11/17/2020] [Accepted: 12/04/2020] [Indexed: 02/03/2023]
Abstract
Epigenetic modification plays a critical role in establishing and maintaining cell differentiation, embryo development, tumorigenesis and many complex diseases. However, little is known about the epigenetic regulatory mechanisms for milk production in dairy cattle. Here, we conducted an epigenome-wide study, together with gene expression profiles to identify important epigenetic candidate genes related to the milk production traits in dairy cattle. Whole-genome bisulphite sequencing and RNA sequencing were employed to detect differentially methylated genes (DMG) and differentially expressed genes (DEG) in blood samples in dry period and lactation period between two groups of cows with extremely high and low milk production performance. A total of 10,877 and 6,617 differentially methylated regions were identified between the two groups in the two periods, which corresponded to 3,601 and 2,802 DMGs, respectively. Furthermore, 156 DEGs overlap with DMGs in comparison of the two groups, and 131 DEGs overlap with DMGs in comparison of the two periods. By integrating methylome, transcriptome and GWAS data, some potential candidate genes for milk production traits in dairy cattle were suggested, such as DOCK1, PTK2 and PIK3R1. Our studies may contribute to a better understanding of epigenetic modification on milk production traits of dairy cattle.
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Affiliation(s)
- Wanting Dong
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture & National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Jie Yang
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture & National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Yu Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture & National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Shuli Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture & National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Chao Ning
- College of Animal Science and Technology, Shandong Agricultural University, Tai'an, China
| | - Xiangdong Ding
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture & National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Wenwen Wang
- College of Animal Science and Technology, Shandong Agricultural University, Tai'an, China
| | - Yi Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture & National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Qin Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture & National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China.,College of Animal Science and Technology, Shandong Agricultural University, Tai'an, China
| | - Li Jiang
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture & National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
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Murray KO, Brant JO, Iwaniec JD, Sheikh LH, de Carvalho L, Garcia CK, Robinson GP, Alzahrani JM, Riva A, Laitano O, Kladde MP, Clanton TL. Exertional heat stroke leads to concurrent long-term epigenetic memory, immunosuppression and altered heat shock response in female mice. J Physiol 2020; 599:119-141. [PMID: 33037634 DOI: 10.1113/jp280518] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/07/2020] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Exposure to exertional heat stroke (EHS) has been linked to increased long-term decrements of health. Epigenetic reprogramming is involved in the response to heat acclimation; however, whether the long-term effects of EHS are mediated by epigenetic reprogramming is unknown. In female mice, we observed DNA methylation reprogramming in bone marrow-derived (BMD) monocytes as early as 4 days of recovery from EHS and as late as 30 days compared with sham exercise controls. Whole blood, collected after 30 days of recovery from EHS, exhibited an immunosuppressive phenotype when challenged in vitro by lipopolysaccharide. After 30 days of recovery from EHS, BMD monocytes exhibited an altered in vitro heat shock response. The location of differentially methylated CpGs are predictive of both the immunosuppressive phenotype and altered heat shock responses. ABSTRACT Exposure to exertional heat stroke (EHS) has been linked to increased susceptibility to a second heat stroke, infection and cardiovascular disease. Whether these clinical outcomes are mediated by an epigenetic memory is unknown. Using a preclinical mouse model of EHS, we investigated whether EHS exposure produces a lasting epigenetic memory in monocytes and whether there are phenotypic alterations that may be consistent with these epigenetic changes. Female mice underwent forced wheel running at 37.5°C/40% relative humidity until symptom limitation, characterized by CNS dysfunction. Results were compared with matched exercise controls at 22.5°C. Monocytes were isolated from bone marrow after 4 or 30 days of recovery to extract DNA and analyse methylation. Broad-ranging alterations to the DNA methylome were observed at both time points. At 30 days, very specific alterations were observed to the promoter regions of genes involved with immune responsiveness. To test whether these changes might be related to phenotype, whole blood at 30 days was challenged with lipopolysaccharide (LPS) to measure cytokine secretion; monocytes were also challenged with heat shock to quantify mRNA expression. Whole blood collected from EHS mice showed markedly attenuated inflammatory responses to LPS challenge. Furthermore, monocyte mRNA from EHS mice showed significantly altered responses to heat shock challenge. These results demonstrate that EHS leads to a unique DNA methylation pattern in monocytes and altered immune and heat shock responsiveness after 30 days. These data support the hypothesis that EHS exposure can induce long-term physiological changes that may be linked to altered epigenetic profiles.
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Affiliation(s)
- Kevin O Murray
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | - Jason O Brant
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL, USA
| | - John D Iwaniec
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | - Laila H Sheikh
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | - Lucas de Carvalho
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | - Christian K Garcia
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | - Gerard P Robinson
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | - Jamal M Alzahrani
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | - Alberto Riva
- Bioinformatics Core, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL, USA
| | - Orlando Laitano
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | - Michael P Kladde
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Thomas L Clanton
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
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8
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Guo G, Wang H, Shi X, Ye L, Yan K, Chen Z, Zhang H, Jin Z, Xue X. Disease Activity-Associated Alteration of mRNA m 5 C Methylation in CD4 + T Cells of Systemic Lupus Erythematosus. Front Cell Dev Biol 2020; 8:430. [PMID: 32582707 PMCID: PMC7291606 DOI: 10.3389/fcell.2020.00430] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 05/08/2020] [Indexed: 01/17/2023] Open
Abstract
Epigenetic processes including RNA methylation, post-translational modifications, and non-coding RNA expression have been associated with the heritable risks of systemic lupus erythematosus (SLE). In this study, we aimed to explore the dysregulated expression of 5-methylcytosine (m5C) in CD4+ T cells from patients with SLE and the potential function of affected mRNAs in SLE pathogenesis. mRNA methylation profiles were ascertained through chromatography-coupled triple quadrupole mass spectrometry in CD4+ T cells from two pools of patients with SLE exhibiting stable activity, two pools with moderate-to-major activity, and two pools of healthy controls (HCs). Simultaneously, mRNA methylation profiles and expression profiling were performed using RNA-Bis-Seq and RNA-Seq, respectively. Integrated mRNA methylation and mRNA expression bioinformatics analysis was comprehensively performed. mRNA methyltransferase NSUN2 expression was validated in CD4+ T cells from 27 patients with SLE and 28 HCs using real-time polymerase chain reaction and western blot analyses. Hypomethylated-mRNA profiles of NSUN2-knockdown HeLa cells and of CD4+ T cells of patients with SLE were jointly analyzed using bioinformatics. Eleven methylation modifications (including elevated Am, 3′OMeA, m1A, and m6A and decreased Ψ, m3C, m1G, m5U, and t6A levels) were detected in CD4+ T cells of patients with SLE. Additionally, decreased m5C levels, albeit increased number of m5C-containing mRNAs, were observed in CD4+ T cells of patients with SLE compared with that in CD4+ T cells of HCs. m5C site distribution in mRNA transcripts was highly conserved and enriched in mRNA translation initiation sites. In particular, hypermethylated m5C or/and significantly up-regulated genes in SLE were significantly involved in immune-related and inflammatory pathways, including immune system, cytokine signaling pathway, and interferon signaling. Compared to that in HCs, NSUN2 expression was significantly lower in SLE CD4+ T cells. Notably, hypomethylated m5C genes in SLE and in NSUN2-knockdown HeLa cells revealed linkage between eukaryotic translation elongation and termination, and mRNA metabolism. Our study identified novel aberrant m5C mRNAs relevant to critical immune pathways in CD4+ T cells from patients with SLE. These data provide valuable perspectives for future studies of the multifunctionality and post-transcriptional significance of mRNA m5C modification in SLE.
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Affiliation(s)
- Gangqiang Guo
- School of Life Sciences and Technology, Tongji University, Shanghai, China.,Department of Microbiology and Immunology, Institute of Molecular Virology and Immunology, Institute of Tropical Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Huijing Wang
- Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Xinyu Shi
- Department of Microbiology and Immunology, Institute of Molecular Virology and Immunology, Institute of Tropical Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Lele Ye
- Department of Microbiology and Immunology, Institute of Molecular Virology and Immunology, Institute of Tropical Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China.,Department of Gynecologic Oncology, Wenzhou Central Hospital, Wenzhou, China
| | - Kejing Yan
- Department of Microbiology and Immunology, Institute of Molecular Virology and Immunology, Institute of Tropical Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Zhiyuan Chen
- Department of Microbiology and Immunology, Institute of Molecular Virology and Immunology, Institute of Tropical Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Huidi Zhang
- Department of Nephrology, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, China
| | - Zibing Jin
- Laboratory for Stem Cell and Retinal Regeneration, Institute of Stem Cell Research, Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Xiangyang Xue
- Department of Microbiology and Immunology, Institute of Molecular Virology and Immunology, Institute of Tropical Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
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9
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Huang H, Zhu Y, Eliot MN, Knopik VS, McGeary JE, Carskadon MA, Hart AC. Combining Human Epigenetics and Sleep Studies in Caenorhabditis elegans: A Cross-Species Approach for Finding Conserved Genes Regulating Sleep. Sleep 2018; 40:3738764. [PMID: 28431118 DOI: 10.1093/sleep/zsx063] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Study Objectives We aimed to test a combined approach to identify conserved genes regulating sleep and to explore the association between DNA methylation and sleep length. Methods We identified candidate genes associated with shorter versus longer sleep duration in college students based on DNA methylation using Illumina Infinium HumanMethylation450 BeadChip arrays. Orthologous genes in Caenorhabditis elegans were identified, and we examined whether their loss of function affected C. elegans sleep. For genes whose perturbation affected C. elegans sleep, we subsequently undertook a small pilot study to re-examine DNA methylation in an independent set of human participants with shorter versus longer sleep durations. Results Eighty-seven out of 485,577 CpG sites had significant differential methylation in young adults with shorter versus longer sleep duration, corresponding to 52 candidate genes. We identified 34 C. elegans orthologs, including NPY/flp-18 and flp-21, which are known to affect sleep. Loss of five additional genes alters developmentally timed C. elegans sleep (B4GALT6/bre-4, DOCK180/ced-5, GNB2L1/rack-1, PTPRN2/ida-1, ZFYVE28/lst-2). For one of these genes, ZFYVE28 (also known as hLst2), the pilot replication study again found decreased DNA methylation associated with shorter sleep duration at the same two CpG sites in the first intron of ZFYVE28. Conclusions Using an approach that combines human epigenetics and C. elegans sleep studies, we identified five genes that play previously unidentified roles in C. elegans sleep. We suggest sleep duration in humans may be associated with differential DNA methylation at specific sites and that the conserved genes identified here likely play roles in C. elegans sleep and in other species.
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Affiliation(s)
- Huiyan Huang
- Department of Neuroscience, Brown University, Providence, RI
| | - Yong Zhu
- Department of Environmental Health Sciences, Yale University School of Public Health, New Haven, CT
| | - Melissa N Eliot
- Department of Epidemiology, Brown University, Providence, RI
| | - Valerie S Knopik
- Division of Behavioral Genetics, Department of Psychiatry, Rhode Island Hospital, Providence, RI.,Department of Psychiatry and Human Behavior, Brown University, Providence, RI
| | - John E McGeary
- Division of Behavioral Genetics, Department of Psychiatry, Rhode Island Hospital, Providence, RI.,Department of Psychiatry and Human Behavior, Brown University, Providence, RI.,Providence Veterans Affairs Medical Center, Providence, RI
| | - Mary A Carskadon
- Department of Psychiatry and Human Behavior, Brown University, Providence, RI.,E.P. Bradley Hospital Sleep Research Laboratory, Providence, RI.,Center for Sleep Research, University of South Australia, Adelaide, Australia
| | - Anne C Hart
- Department of Neuroscience, Brown University, Providence, RI
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10
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Varghese VK, Shukla V, Kabekkodu SP, Pandey D, Satyamoorthy K. DNA methylation regulated microRNAs in human cervical cancer. Mol Carcinog 2017; 57:370-382. [PMID: 29077234 DOI: 10.1002/mc.22761] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 10/17/2017] [Accepted: 10/23/2017] [Indexed: 01/19/2023]
Abstract
Regulation of miRNA gene expression by DNA promoter methylation may represent a key mechanism to drive cervical cancer progression. In order to understand the impact of DNA promoter methylation on miRNAs at various stages of cervical carcinogenesis, we performed DNA methylation microarray on Normal Cervical Epithelium (NCE), Cervical Intraepithelial Neoplasia (CIN I-III) and Squamous Cell Carcinoma (SCC) tissues to identify differentially methylated miRNAs followed by validation by bisulfite sequencing. Further, expression of miRNAs was analyzed by qRT-PCR in clinical tissues and cervical cancer cell lines. Transcriptional activity was determined by luciferase assay. We identified a total of 69 hypermethylated and hypomethylated miRNA promoters encompassing 78 CpG islands in all except Y chromosome, among the three groups. The candidate DNA promoters of miR-424 were significantly hypermethylated and miR-200b and miR-34c were significantly hypomethylated in SCC compared to NCE (P < 0.05). Expression of miR-424, miR-200b, and miR-34c were inversely correlated with promoter DNA methylation in tissue samples. Treatment of cell lines with 5-aza-2'-deoxycytidine showed differential expression in all three miRNAs. We observed a decrease in miRNA promoter activity following in vitro SssI methylase treatment of miR-424, miR-200b, and miR-34c. Luciferase assay demonstrated that miR-200b and miR-424 functionally interacts with 3'-UTR of HIPK3 and RBBP6 respectively and decreased their activity in presence of miR-200b and miR-424 mimics transfected in SiHa cells. Taken together, we have identified deregulation of miRNAs by aberrant DNA promoter methylation, leading to its transcriptional silencing during cervical carcinogenesis, which can be potential targets for diagnosis and therapy.
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Affiliation(s)
- Vinay K Varghese
- Department of Cell and Molecular Biology, School of Life Sciences, Manipal University, Manipal, Karnataka, India
| | - Vaibhav Shukla
- Department of Cell and Molecular Biology, School of Life Sciences, Manipal University, Manipal, Karnataka, India
| | - Shama P Kabekkodu
- Department of Cell and Molecular Biology, School of Life Sciences, Manipal University, Manipal, Karnataka, India
| | - Deeksha Pandey
- Department of Obstetrics and Gynecology, Kasturba Medical College, Manipal University, Manipal, Karnataka, India
| | - Kapaettu Satyamoorthy
- Department of Cell and Molecular Biology, School of Life Sciences, Manipal University, Manipal, Karnataka, India
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11
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Genome-wide alteration in DNA hydroxymethylation in the sperm from bisphenol A-exposed men. PLoS One 2017; 12:e0178535. [PMID: 28582417 PMCID: PMC5459435 DOI: 10.1371/journal.pone.0178535] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 05/15/2017] [Indexed: 12/16/2022] Open
Abstract
Environmental BPA exposure has been shown to impact human sperm concentration and motility, as well as rodent spermatogenesis. However, it is unclear whether BPA exposure is associated with alteration in DNA hydroxymethylation, a marker for epigenetic modification, in human sperm. A genome-wide DNA hydroxymethylation study was performed using sperm samples of men who were occupationally exposed to BPA. Compared with controls who had no occupational BPA exposure, the total levels of 5-hydroxymethylcytosine (5hmc) increased significantly (19.37% increase) in BPA-exposed men, with 72.69% of genome regions harboring 5hmc. A total of 9,610 differential 5hmc regions (DhMRs) were revealed in BPA-exposed men relative to controls, which were mainly located in intergenic and intron regions. These DhMRs were composed of 8,670 hyper-hMRs and 940 hypo-hMRs, affecting 2,008 genes and the repetitive elements. The hyper-hMRs affected genes were enriched in pathways associated with nervous system, development, cardiovascular diseases and signal transduction. Additionally, enrichment of 5hmc was observed in the promoters of eight maternally expressed imprinted genes in BPA-exposed sperm. Some of the BPA-affected genes, for example, MLH1, CHD2, SPATA12 and SPATA20 might participate in the response to DNA damage in germ cells caused by BPA. Our analysis showed that enrichment of 5hmc both in promoters and gene bodies is higher in the genes whose expression has been detected in human sperm than those whose expression is absent. Importantly, we observed that BPA exposure affected the 5hmc level in 11.4% of these genes expressed in sperm, and in 6.85% of the sperm genome. Finally, we also observed that BPA exposure tends to change the 5hmc enrichment in the genes which was previously reported to be distributed with the trimethylated Histone 3 (H3K27me3, H3K4me2 or H3K4me3) in sperm. Thus, these results suggest that BPA exposure likely interferes with gene expression via affecting DNA hydroxymethylation in a way partially dependent on trimethylation of H3 in human spermatogenesis. Our current study reveals a new mechanism by which BPA exposure reduces human sperm quality.
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12
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Begue G, Raue U, Jemiolo B, Trappe S. DNA methylation assessment from human slow- and fast-twitch skeletal muscle fibers. J Appl Physiol (1985) 2017; 122:952-967. [PMID: 28057818 DOI: 10.1152/japplphysiol.00867.2016] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/07/2016] [Accepted: 12/30/2016] [Indexed: 11/22/2022] Open
Abstract
A new application of the reduced representation bisulfite sequencing method was developed using low-DNA input to investigate the epigenetic profile of human slow- and fast-twitch skeletal muscle fibers. Successful library construction was completed with as little as 15 ng of DNA, and high-quality sequencing data were obtained with 32 ng of DNA. Analysis identified 143,160 differentially methylated CpG sites across 14,046 genes. In both fiber types, selected genes predominantly expressed in slow or fast fibers were hypomethylated, which was supported by the RNA-sequencing analysis. These are the first fiber type-specific methylation data from human skeletal muscle and provide a unique platform for future research.NEW & NOTEWORTHY This study validates a low-DNA input reduced representation bisulfite sequencing method for human muscle biopsy samples to investigate the methylation patterns at a fiber type-specific level. These are the first fiber type-specific methylation data reported from human skeletal muscle and thus provide initial insight into basal state differences in myosin heavy chain I and IIa muscle fibers among young, healthy men.
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Affiliation(s)
- Gwénaëlle Begue
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Ulrika Raue
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Bozena Jemiolo
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Scott Trappe
- Human Performance Laboratory, Ball State University, Muncie, Indiana
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13
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Legendre C, Gooden GC, Johnson K, Martinez RA, Liang WS, Salhia B. Whole-genome bisulfite sequencing of cell-free DNA identifies signature associated with metastatic breast cancer. Clin Epigenetics 2015; 7:100. [PMID: 26380585 PMCID: PMC4573288 DOI: 10.1186/s13148-015-0135-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 09/08/2015] [Indexed: 01/28/2023] Open
Abstract
Background A number of clinico-pathological criteria and molecular profiles have been used to stratify patients into high- and low-risk groups. Currently, there are still no effective methods to determine which patients harbor micrometastatic disease after standard breast cancer therapy and who will eventually develop local or distant recurrence. The purpose of our study was to identify circulating DNA methylation changes that can be used for prediction of metastatic breast cancer (MBC). Results Differential methylation analysis revealed ~5.0 × 106 differentially methylated CpG loci in MBC compared with healthy individuals (H) or disease-free survivors (DFS). In contrast, there was a strong degree of similarity between H and DFS. Overall, MBC demonstrated global hypomethylation and focal CpG island (CPGI) hypermethylation. Data analysis identified 21 novel hotspots, within CpG islands, that differed most dramatically in MBC compared with H or DFS. Conclusions This unbiased analysis of cell-free (cf) DNA identified 21 DNA hypermethylation hotspots associated with MBC and demonstrated the ability to distinguish tumor-specific changes from normal-derived signals at the whole-genome level. This signature is a potential blood-based biomarker that could be advantageous at the time of surgery and/or after the completion of chemotherapy to indicate patients with micrometastatic disease who are at a high risk of recurrence and who could benefit from additional therapy. Electronic supplementary material The online version of this article (doi:10.1186/s13148-015-0135-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christophe Legendre
- Integrated Cancer Genomics Division, Translational Genomics Research Institute, 445 N Fifth Street, Phoenix, AZ USA
| | - Gerald C Gooden
- Integrated Cancer Genomics Division, Translational Genomics Research Institute, 445 N Fifth Street, Phoenix, AZ USA
| | - Kyle Johnson
- Integrated Cancer Genomics Division, Translational Genomics Research Institute, 445 N Fifth Street, Phoenix, AZ USA
| | - Rae Anne Martinez
- Integrated Cancer Genomics Division, Translational Genomics Research Institute, 445 N Fifth Street, Phoenix, AZ USA
| | - Winnie S Liang
- Integrated Cancer Genomics Division, Translational Genomics Research Institute, 445 N Fifth Street, Phoenix, AZ USA
| | - Bodour Salhia
- Integrated Cancer Genomics Division, Translational Genomics Research Institute, 445 N Fifth Street, Phoenix, AZ USA
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14
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DNA methylation levels are highly correlated between pooled samples and averaged values when analysed using the Infinium HumanMethylation450 BeadChip array. Clin Epigenetics 2015; 7:78. [PMID: 26236407 PMCID: PMC4521379 DOI: 10.1186/s13148-015-0097-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 06/22/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND DNA methylation is a heritable and stable epigenetic mark implicated in complex human traits. Epigenome-wide association studies (EWAS) using array-based technology are becoming widely used to identify differentially methylated sites associated with complex diseases. EWAS studies require large sample sizes to detect small effects, which increases project costs. In the present study we propose to pool DNA samples in methylation array studies as an affordable and accurate alternative to individual samples studies, in order to reduce economic costs or when low amounts of DNA are available. For this study, 20 individual DNA samples and 4 pooled DNA samples were analysed using the Illumina Infinium HumanMethylation450 BeadChip array to evaluate the efficiency of the pooling approach in EWAS studies. Statistical power calculations were also performed to discover the minimum sample size needed for the pooling strategy in EWAS. RESULTS A total of 485,577 CpG sites across the whole genome were assessed. Comparison of methylation levels of all CpG sites between individual samples and their related pooled samples revealed highly significant correlations (rho > 0.99, p-val < 10(-16)). These results remained similar when assessing the 101 most differentially methylated CpG sites (rho > 0.98, p-val < 10(-16)). Also, it was calculated that n = 43 is the minimum sample size required to achieve a 95 % statistical power and a 10(-06) significance level in EWAS, when using a DNA pool strategy. CONCLUSIONS DNA pooling strategies seems to accurately provide estimations of averaged DNA methylation state using array based EWAS studies. This type of approach can be applied to the assessment of disease phenotypes, reducing the amount of DNA required and the cost of large-scale epigenetic analyses.
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15
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Xu Y, Chen XT, Luo M, Tang Y, Zhang G, Wu D, Yang B, Ruan DY, Wang HL. Multiple epigenetic factors predict the attention deficit/hyperactivity disorder among the Chinese Han children. J Psychiatr Res 2015; 64:40-50. [PMID: 25840828 DOI: 10.1016/j.jpsychires.2015.03.006] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 03/06/2015] [Accepted: 03/11/2015] [Indexed: 11/30/2022]
Abstract
Attention deficit/hyperactivity disorder (ADHD) is one of the most common psychiatric disorders of childhood. Despite its prevalence, the critical factors involved in its development remain to be identified. It was recently suggested that epigenetic mechanisms probably contribute to the etiology of ADHD. The present study was designed to examine the associations of epigenetic markers with ADHD among Chinese Han children, aiming to establish the prediction model for this syndrome from the epigenetic perspective. We conducted a pair-matching case-control study, and the ADHD children were systematically evaluated via structured diagnostic interviews, including caregiver interviews, based on the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, revised criteria (DSM-IV-R). The expression levels of risk genes DAT1, DRD4, DRD5, as well as their promoter methylation, were determined respectively, followed by the expression profiles of histone-modifying genes p300, MYST4, HDAC1, MeCP2. The multivariate logistic regressions were performed to establish ADHD prediction models. All of the seven genes tested were identified as risk factors for ADHD. The methylation of one critical CpG site located upstream of DRD4 was shown to affect its transcription, suggesting a role in ADHD's development. Aberrant DNA methylation and histone acetylation were indicated in ADHD patients. In addition, a prediction model was established using the combination of p300, MYST4 and HDAC1, with the accuracy of 0.9338. This is, to our knowledge, the first study to clearly demonstrate the associations between epigenetic markers and ADHD, shedding light on the preliminary diagnosis and etiological studies of this widespread disorder.
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Affiliation(s)
- Yi Xu
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui Province, 230009, PR China.
| | - Xiang-Tao Chen
- School of Pharmacy, Anhui Medical University, Hefei, Anhui Province, 230031, PR China.
| | - Man Luo
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui Province, 230009, PR China.
| | - Yuqing Tang
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui Province, 230009, PR China.
| | - Guangxiang Zhang
- Biostatistics and Data Management Core, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA.
| | - De Wu
- Department of Pediatrics, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, 230022, PR China.
| | - Bin Yang
- Department of Child Neurology, Anhui Provincial Children's Hospital, Hefei, Anhui Province, 230031, PR China.
| | - Di-Yun Ruan
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui Province, 230009, PR China; School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, PR China.
| | - Hui-Li Wang
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui Province, 230009, PR China.
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16
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Huang RC, Garratt ES, Pan H, Wu Y, Davis EA, Barton SJ, Burdge GC, Godfrey KM, Holbrook JD, Lillycrop KA. Genome-wide methylation analysis identifies differentially methylated CpG loci associated with severe obesity in childhood. Epigenetics 2015; 10:995-1005. [PMID: 26646899 PMCID: PMC4844195 DOI: 10.1080/15592294.2015.1080411] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 07/27/2015] [Accepted: 08/01/2015] [Indexed: 12/24/2022] Open
Abstract
Childhood obesity is a major public health issue. Here we investigated whether differential DNA methylation was associated with childhood obesity. We studied DNA methylation profiles in whole blood from 78 obese children (mean BMI Z-score: 2.6) and 71 age- and sex-matched controls (mean BMI Z-score: 0.1). DNA samples from obese and control groups were pooled and analyzed using the Infinium HumanMethylation450 BeadChip array. Comparison of the methylation profiles between obese and control subjects revealed 129 differentially methylated CpG (DMCpG) loci associated with 80 unique genes that had a greater than 10% difference in methylation (P-value < 0.05). The top pathways enriched among the DMCpGs included developmental processes, immune system regulation, regulation of cell signaling, and small GTPase-mediated signal transduction. The associations between the methylation of selected DMCpGs with childhood obesity were validated using sodium bisulfite pyrosequencing across loci within the FYN, PIWIL4, and TAOK3 genes in individual subjects. Three CpG loci within FYN were hypermethylated in obese individuals (all P < 0.01), while obesity was associated with lower methylation of CpG loci within PIWIL4 (P = 0.003) and TAOK3 (P = 0.001). After building logistic regression models, we determined that a 1% increase in methylation in TAOK3, multiplicatively decreased the odds of being obese by 0.91 (95% CI: 0.86 - 0.97), and an increase of 1% methylation in FYN CpG3, multiplicatively increased the odds of being obese by 1.03 (95% CI: 0.99 - 1.07). In conclusion, these findings provide evidence that childhood obesity is associated with specific DNA methylation changes in whole blood, which may have utility as biomarkers of obesity risk.
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Affiliation(s)
- R C Huang
- Telethon Institute for Child Health Research; University of Western Australia; Perth, Australia
| | - E S Garratt
- Academic Unit of Human Development and Health; Faculty of Medicine; University of Southampton; Southampton, UK
| | - H Pan
- Singapore Institute for Clinical Sciences (SICS); A*STAR; Brenner Center for Molecular Medicine; Singapore
- School of Computer Engineering; Nanyang Technological University (NTU); Singapore
| | - Y Wu
- Singapore Institute for Clinical Sciences (SICS); A*STAR; Brenner Center for Molecular Medicine; Singapore
| | - E A Davis
- Telethon Institute for Child Health Research; University of Western Australia; Perth, Australia
| | - S J Barton
- MRC Lifecourse Epidemiology Unit; University of Southampton; Southampton, UK
| | - G C Burdge
- Academic Unit of Human Development and Health; Faculty of Medicine; University of Southampton; Southampton, UK
| | - K M Godfrey
- MRC Lifecourse Epidemiology Unit; University of Southampton; Southampton, UK
- NIHR Southampton Biomedical Research Center; University of Southampton and University Hospital Southampton NHS Foundation Trust; Southampton, UK
| | - J D Holbrook
- Singapore Institute for Clinical Sciences (SICS); A*STAR; Brenner Center for Molecular Medicine; Singapore
- Yong Loo Lin School of Medicine; National University of Singapore (NUS); Singapore
| | - K A Lillycrop
- Academic Unit of Human Development and Health; Faculty of Medicine; University of Southampton; Southampton, UK
- Faculty of Natural and Environmental Sciences; University of Southampton; Southampton, UK
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17
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Zhai R, Wei Y, Su L, Liu G, Kulke MH, Wain JC, Christiani DC. Whole-miRNome profiling identifies prognostic serum miRNAs in esophageal adenocarcinoma: the influence of Helicobacter pylori infection status. Carcinogenesis 2014; 36:87-93. [PMID: 25381453 DOI: 10.1093/carcin/bgu228] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cell free circulating microRNAs (cfmiRNAs) have been recognized as robust and stable biomarkers of cancers. However, little is known about the prognostic significance of cfmiRNAs in esophageal adenocarcinoma (EA). In this study, we explored whether specific cfmiRNA profiles could predict EA prognosis and whether Helicobacter pylori (HP) infection status could influence the association between cfmiRNAs and EA survival outcome. We profiled 1075 miRNAs in pooled serum samples from 30 EA patients and 30 healthy controls. The most relevant cfmiRNAs were then assessed for their associations with EA survival in an independent cohort of 82 patients, using Log-rank test and multivariate Cox regression models. Quantitative real-time PCR (qRT-PCR) was used for cfmiRNA profiling. HP infection status was determined by immunoblotting assay. We identified a panel of 18 cfmiRNAs that could distinguish EA patients from healthy subjects (P = 3.0E-12). In overall analysis and in HP-positive subtype patients, no cfmiRNA was significantly associated with EA prognosis. In HP-negative patients, however, 15 cfmiRNAs were significantly associated with overall survival (OS) (all P < 0.05). A combined 2-cfmiRNA (low miR-3935 and high miR-4286) risk score was constructed; that showed greater risk for worse OS (HR = 2.22, P = 0.0019) than individual cfmiRNA alone. Patients with high-risk score had >10-fold increased risk of death than patients with low risk score (P = 0.0302; HR = 10.91; P = 0.0094). Our findings suggest that dysregulated cfmiRNAs may contribute to EA survival outcome and HP infection status may modify the association between cfmiRNAs and EA survival.
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Affiliation(s)
- Rihong Zhai
- Shenzhen Key Laboratory of Translational Medicine of Tumor, Shenzhen University School of Medicine, Shenzhen 518060, China, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA, Medical Oncology and Haematology, Department of Medicine, Princess Margaret Hospital, Toronto, Ontario M5G 2C4, Canada, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA and Department of Surgery and Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Yongyue Wei
- Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA
| | - Li Su
- Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA
| | - Geoffrey Liu
- Medical Oncology and Haematology, Department of Medicine, Princess Margaret Hospital, Toronto, Ontario M5G 2C4, Canada
| | - Mathew H Kulke
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA and
| | | | - David C Christiani
- Medical Oncology and Haematology, Department of Medicine, Princess Margaret Hospital, Toronto, Ontario M5G 2C4, Canada, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
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18
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Zhao M, Liu S, Luo S, Wu H, Tang M, Cheng W, Zhang Q, Zhang P, Yu X, Xia Y, Yi N, Gao F, Wang L, Yung S, Chan TM, Sawalha AH, Richardson B, Gershwin ME, Li N, Lu Q. DNA methylation and mRNA and microRNA expression of SLE CD4+ T cells correlate with disease phenotype. J Autoimmun 2014; 54:127-36. [PMID: 25091625 DOI: 10.1016/j.jaut.2014.07.002] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 07/02/2014] [Accepted: 07/08/2014] [Indexed: 11/26/2022]
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease well known for its clinical heterogeneity, and its etiology secondary to a cross-talk involving genetic predisposition and environmental stimuli. Although genome-wide analysis has contributed greatly to our understanding of the genetic basis of SLE, there is increasing evidence for a role of epigenetics. Indeed, recent data have demonstrated that in patients with SLE, there are striking alterations of DNA methylation, histone modifications, and deregulated microRNA expression, the sum of which contribute to over-expression of select autoimmune-related genes and loss of tolerance. To address this issue at the level of clinical phenotype, we performed DNA methylation, mRNA and microRNA expression screening using high-throughput sequencing of purified CD4+ T cells from patients with SLE, compared to age and sex matched controls. In particular, we studied 42 patients with SLE and divided this group into three clinical phenotypes: a) the presence of skin lesions without signs of systemic pathology; b) skin lesions but also chronic renal pathology; and c) skin lesions, chronic renal pathology and polyarticular disease. Interestingly, and as expected, sequencing data revealed changes in DNA methylation in SLE compared to controls. However, and more importantly, although there were common methylation changes found in all groups of SLE compared to controls, there was specific DNA methylation changes that correlated with clinical phenotype. These included changes in the novel key target genes NLRP2, CD300LB and S1PR3, as well as changes in the critical pathways, including the adherens junction and leukocyte transendothelial migration. We also noted that a significant proportion of genes undergoing DNA methylation changes were inversely correlated with gene expression and that miRNA screening revealed the existence of subsets with changes in expression. Integrated analysis of this data highlights specific sets of miRNAs controlled by DNA methylation, and genes that are altered by methylation and targeted by miRNAs. In conclusion, our findings suggest select epigenetic mechanisms that contribute to clinical phenotypes and further shed light on a new venue for basic SLE research.
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Affiliation(s)
- Ming Zhao
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Hunan Key Laboratory of Medical Epigenomics, Changsha, Hunan, China
| | - Siyang Liu
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Shuangyan Luo
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Hunan Key Laboratory of Medical Epigenomics, Changsha, Hunan, China
| | - Honglong Wu
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Meini Tang
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Hunan Key Laboratory of Medical Epigenomics, Changsha, Hunan, China
| | - Wenjing Cheng
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Hunan Key Laboratory of Medical Epigenomics, Changsha, Hunan, China
| | - Qing Zhang
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Hunan Key Laboratory of Medical Epigenomics, Changsha, Hunan, China
| | - Peng Zhang
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Hunan Key Laboratory of Medical Epigenomics, Changsha, Hunan, China
| | - Xinhai Yu
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Hunan Key Laboratory of Medical Epigenomics, Changsha, Hunan, China
| | - Yudong Xia
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Na Yi
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Fei Gao
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Li Wang
- Beijing Genomics Institute at Shenzhen, Shenzhen, China
| | - Susan Yung
- Division of Nephrology, Department of Medicine, University of Hong Kong, Queen Mary Hospital, Hong Kong, China
| | - Tak Mao Chan
- Division of Nephrology, Department of Medicine, University of Hong Kong, Queen Mary Hospital, Hong Kong, China
| | - Amr H Sawalha
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Bruce Richardson
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - M Eric Gershwin
- Division of Rheumatology, Allergy and Clinical Immunology, University of California, Davis, CA, USA
| | - Ning Li
- Beijing Genomics Institute at Shenzhen, Shenzhen, China.
| | - Qianjin Lu
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Hunan Key Laboratory of Medical Epigenomics, Changsha, Hunan, China.
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19
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Song Y, Miyaki K, Suzuki T, Sasaki Y, Tsutsumi A, Kawakami N, Shimazu A, Takahashi M, Inoue A, Kan C, Kurioka S, Shimbo T. Altered DNA methylation status of human brain derived neurotrophis factor gene could be useful as biomarker of depression. Am J Med Genet B Neuropsychiatr Genet 2014; 165B:357-64. [PMID: 24801253 PMCID: PMC4321058 DOI: 10.1002/ajmg.b.32238] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 04/14/2014] [Indexed: 12/15/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is involved in the survival, development, and synaptic plasticity of neurons. BDNF is believed to be associated with the pathophysiology of psychiatric disorders. Several studies have suggested the relevance of DNA methylation in its promoter region with depression. Here, we report different methylation statuses in groups with different depressive scores or undergoing different levels of job-stress. DNA samples were extracted from the saliva of 774 Japanese workers, and the methylation status was determined using the Illumina HumanMethylation 450 K Microarray. Depressive symptoms were measured using the Kessler's K6 questionnaire. Job-stress scales were assessed via a self-administered questionnaire. Independent DNA pools were formed based on K6 and job-strain scores, and the methylation levels were compared among these pools. The average DNA methylation rate was significantly decreased in the highest K6 score group compared to the lowest group (methylated signals, 14.2% vs. 16.5%, P = 2 · 16 × 10(-198)). This difference remained for the CpG island in the promoter region (10.4% vs. 5.8%, P = 3 · 67 × 10(-133)). Regarding the job-strain score, there was a slight increase in the methylation level of the whole gene in the group with the highest score compared to that with the lowest score; however, these groups showed no difference in the promoter region. Our results revealed significant changes in the DNA methylation status of the complete human BDNF gene in persons with depression compared to normal individuals, especially in the promoter region of exon 1. This indicates that DNA methylation in this gene is a promising biomarker for diagnosing depression.
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Affiliation(s)
- Yixuan Song
- Department of Clinical Research and Informatics, National Center for Global Health and MedicineTokyo, Japan
| | - Koichi Miyaki
- Department of Clinical Research and Informatics, National Center for Global Health and MedicineTokyo, Japan,*Correspondence to:, Koichi Miyaki, M.D., Ph.D., Department of Clinical Research and Informatics, National Center for Global Health and Medicine, Toyama 1-21-1, Shinjuku-ku, Tokyo, 162-8655, Japan., E-mail:
| | - Tomoko Suzuki
- Department of Clinical Research and Informatics, National Center for Global Health and MedicineTokyo, Japan
| | - Yasuharu Sasaki
- Department of Clinical Research and Informatics, National Center for Global Health and MedicineTokyo, Japan
| | - Akizumi Tsutsumi
- Department of Public Health, Kitasato University School of MedicineSagamihara, Kanagawa, Japan
| | - Norito Kawakami
- Department of Mental Health, Tokyo University Graduate School of MedicineTokyo, Japan
| | - Akihito Shimazu
- Department of Mental Health, Tokyo University Graduate School of MedicineTokyo, Japan
| | - Masaya Takahashi
- Health Administration and Psychosocial Factor Research Group, National Institute of Occupational Safety and HealthKawasaki, Kanagawa, Japan
| | - Akiomi Inoue
- Department of Mental HealthInstitute of Industrial Ecological Sciences, University of Occupational and Environmental HealthKitakyushu, Fukuoka, Japan
| | - Chiemi Kan
- Department of Mental Health, Tokyo University Graduate School of MedicineTokyo, Japan
| | - Sumiko Kurioka
- Department of Health Policy and Management, University of Occupational and Environmental HealthKitakyushu, Fukuoka, Japan
| | - Takuro Shimbo
- Department of Clinical Research and Informatics, National Center for Global Health and MedicineTokyo, Japan
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20
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Martino D, Joo JE, Sexton-Oates A, Dang T, Allen K, Saffery R, Prescott S. Epigenome-wide association study reveals longitudinally stable DNA methylation differences in CD4+ T cells from children with IgE-mediated food allergy. Epigenetics 2014; 9:998-1006. [PMID: 24762976 DOI: 10.4161/epi.28945] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED Food allergy is mediated by a combination of genetic and environmental risk factors, potentially mediated by epigenetic mechanisms. CD4+ T-cells are key drivers of the allergic response, and may therefore harbor epigenetic variation in association with the disease phenotype. Here we retrospectively examined genome-wide DNA methylation profiles (~450,000 CpGs) from CD4+ T-cells on a birth cohort of 12 children with IgE-mediated food allergy diagnosed at 12-months, and 12 non-allergic controls. DNA samples were available at two time points, birth and 12-months. CASE control comparisons of CD4+ methylation profiles identified 179 differentially methylated probes (DMP) at 12-months and 136 DMP at birth (FDR-adjusted P value<0.05, delta β>0.1). Approximately 30% of DMPs were coincident with previously annotated SNPs. A total of 92 [corrected] allergy-associated non-SNP DMPs were present at birth when individuals were initially disease-free, potentially implicating these loci in the causal pathway. Pathway analysis of differentially methylated genes identified several MAP kinase signaling molecules. Mass spectrometry was used to validate 15 CpG sites at 3 candidate genes. Combined analysis of differential methylation with gene expression profiles revealed gene expression differences at some but not all allergy associated differentially methylated genes. Thus, dysregulation of DNA methylation at MAPK signaling-associated genes during early CD4+ T-cell development may contribute to suboptimal T-lymphocyte responses in early childhood associated with the development of food allergy.
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Affiliation(s)
- David Martino
- Murdoch Childrens Research Institute; Royal Children's Hospital; Melbourne, VIC Australia; NHMRC Centre for Food and Allergy Research; Murdoch Childrens Research Institute; Royal Children's Hospital; Melbourne, VIC Australia; Honorary Fellow University of Melbourne; Melbourne, VIC Australia
| | - Jihoon E Joo
- Murdoch Childrens Research Institute; Royal Children's Hospital; Melbourne, VIC Australia
| | - Alexandra Sexton-Oates
- Murdoch Childrens Research Institute; Royal Children's Hospital; Melbourne, VIC Australia
| | - Thanh Dang
- Murdoch Childrens Research Institute; Royal Children's Hospital; Melbourne, VIC Australia
| | - Katrina Allen
- Murdoch Childrens Research Institute; Royal Children's Hospital; Melbourne, VIC Australia; NHMRC Centre for Food and Allergy Research; Murdoch Childrens Research Institute; Royal Children's Hospital; Melbourne, VIC Australia
| | - Richard Saffery
- Murdoch Childrens Research Institute; Royal Children's Hospital; Melbourne, VIC Australia
| | - Susan Prescott
- Childhood Allergy and Immunology Research; School of Paediatrics and Child Health; University of Western Australia; Crawley, WA Australia
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Gender-specific DNA methylome analysis of a Han Chinese longevity population. BIOMED RESEARCH INTERNATIONAL 2014; 2014:396727. [PMID: 24822201 PMCID: PMC4009103 DOI: 10.1155/2014/396727] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 02/28/2014] [Indexed: 01/06/2023]
Abstract
Human longevity is always a biological hotspot and so much effort has been devoted to identifying genes and genetic variations associated with longer lives. Most of the demographic studies have highlighted that females have a longer life span than males. The reasons for this are not entirely clear. In this study, we carried out a pool-based, epigenome-wide investigation of DNA methylation profiles in male and female nonagenarians/centenarians using the Illumina 450 K Methylation Beadchip assays. Although no significant difference was detected for the average methylation levels of examined CpGs (or probes) between male and female samples, a significant number of differentially methylated probes (DMPs) were identified, which appeared to be enriched in certain chromosome regions and certain parts of genes. Further analysis of DMP-containing genes (named DMGs) revealed that almost all of them are solely hypermethylated or hypomethylated. Functional enrichment analysis of these DMGs indicated that DNA hypermethylation and hypomethylation may regulate genes involved in different biological processes, such as hormone regulation, neuron projection, and disease-related pathways. This is the first effort to explore the gender-based methylome difference in nonagenarians/centenarians, which may provide new insights into the complex mechanism of longevity gender gap of human beings.
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Epigenetic patterns of two gene promoters (TNF-α and PON) in stroke considering obesity condition and dietary intake. J Physiol Biochem 2014; 70:603-14. [PMID: 24500802 DOI: 10.1007/s13105-014-0316-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 01/20/2014] [Indexed: 12/25/2022]
Abstract
Some causal bases of stroke remain unclear, but the nutritional effects on the epigenetic regulation of different genes may be involved. The aim was to assess the impact of epigenetic processes of human tumor necrosis factor (TNF-α) and paraoxonase (PON) promoters in the susceptibility to stroke when considering body composition and dietary intake. Twenty-four patients (12 non-stroke/12 stroke) were matched by sex (12 male/12 female), age (mean 70 ± 12 years old), and BMI (12 normal-weight/12 obese; mean 28.1 ± 6.7 kg/m(2)). Blood cell DNA was isolated and DNA methylation levels of TNF-α (-186 to +349 bp) and PON (-231 to +250 bp) promoters were analyzed by the Sequenom EpiTYPER approach. Histone modifications (H3K9ac and H3K4me3) were analyzed also by chromatin immunoprecipitation in a region of TNF-α (-297 to -185). Total TNF-α promoter methylation was lower in stroke patients (p < 0.001) and showed no interaction with body composition (p = 0.807). TNF-α and PON total methylation levels correlated each other (r = 0.44; p = 0.031), especially in stroke patients (r = 0.72; p = 0.008). The +309 CpG methylation site from TNF-α promoter was related to body weight (p = 0.027) and the region containing three CpGs (from -170 to -162 bp) to the percentage of lipid intake and dietary indexes (p < 0.05) in non-stroke patients. The methylation of PON +15 and +241 CpGs was related to body weight (p = 0.021), waist circumference (p = 0.020), and energy intake (p = 0.018), whereas +214 was associated to the quality of the diet (p < 0.05) in non-stroke patients. When comparing stroke vs non-stroke patients regarding the histone modifications analyzed at TNF-α promoter, no changes were found, although a significant association was identified between circulating TNF-α level and H3K9ac with H3K4me3. TNF-α and PON promoter methylation levels could be involved in the susceptibility to stroke and obesity outcome, respectively. The dietary intake and body composition may influence this epigenetic regulation in non-stroke patients.
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Barua S, Kuizon S, Chadman KK, Flory MJ, Brown WT, Junaid MA. Single-base resolution of mouse offspring brain methylome reveals epigenome modifications caused by gestational folic acid. Epigenetics Chromatin 2014; 7:3. [PMID: 24484737 PMCID: PMC3928622 DOI: 10.1186/1756-8935-7-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 01/07/2014] [Indexed: 12/29/2022] Open
Abstract
Background Epigenetic modifications, such as cytosine methylation in CpG-rich regions, regulate multiple functions in mammalian development. Maternal nutrients affecting one-carbon metabolism during gestation can exert long-term effects on the health of the progeny. Using C57BL/6 J mice, we investigated whether the amount of ingested maternal folic acid (FA) during gestation impacted DNA methylation in the offspring’s cerebral hemispheres. Reduced representation bisulfite sequencing at single-base resolution was performed to analyze genome-wide DNA methylation profiles. Results We identified widespread differences in the methylation patterns of CpG and non-CpG sites of key developmental genes, including imprinted and candidate autism susceptibility genes (P <0.05). Such differential methylation of the CpG and non-CpG sites may use different mechanisms to alter gene expressions. Quantitative real time reverse transcription-polymerase chain reaction confirmed altered expression of several genes. Conclusions These finding demonstrate that high maternal FA during gestation induces substantial alteration in methylation pattern and gene expression of several genes in the cerebral hemispheres of the offspring, and such changes may influence the overall development. Our findings provide a foundation for future studies to explore the influence of gestational FA on genetic/epigenetic susceptibility to altered development and disease in offspring.
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Affiliation(s)
| | | | | | | | | | - Mohammed A Junaid
- Department of Developmental Biochemistry, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA.
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Bayles R, Baker EK, Jowett JBM, Barton D, Esler M, El-Osta A, Lambert G. Methylation of the SLC6a2 gene promoter in major depression and panic disorder. PLoS One 2013; 8:e83223. [PMID: 24312678 PMCID: PMC3847099 DOI: 10.1371/journal.pone.0083223] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 11/11/2013] [Indexed: 01/11/2023] Open
Abstract
Reduced function of the noradrenaline transporter (NET) has been demonstrated in patients with major depressive disorder (MDD) and panic disorder. Attempts to explain NET dysfunction in MDD and panic disorder by genetic variation in the NET gene SLC6a2 have been inconclusive. Transcriptional silencing of the SLC6a2 gene may be an alternative mechanism which can lead to NET dysfunction independent of DNA sequence. The objective of this study was to characterise the DNA methylation state of the SLC6a2 gene promoter in patients with MDD and panic disorder. SLC6a2 promoter methylation was also analysed before and after antidepressant treatment. This study was performed with DNA from blood, using bisulphite sequencing and EpiTYPER methylation analyses. Patients with MDD or panic disorder were not found to differ significantly from healthy controls in the pattern of methylation of the SLC6a2 gene promotor. While significant correlations between methylation levels at some CpG sites and physiological measures were identified, overall the variation in DNA methylation between patients was small, and the significance of this variation remains equivocal. No significant changes in SLC6a2 promoter methylation were observed in response to antidepressant treatment. Further in-depth analysis of alternative mechanisms of transcriptional regulation of the SLC6a2 gene in human health and disease would be of value.
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Affiliation(s)
- Richard Bayles
- Baker IDI Heart & Diabetes Institute, Melbourne, Australia
- * E-mail:
| | | | | | - David Barton
- Baker IDI Heart & Diabetes Institute, Melbourne, Australia
| | - Murray Esler
- Baker IDI Heart & Diabetes Institute, Melbourne, Australia
| | - Assam El-Osta
- Baker IDI Heart & Diabetes Institute, Melbourne, Australia
| | - Gavin Lambert
- Baker IDI Heart & Diabetes Institute, Melbourne, Australia
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Genome-wide analysis of DNA methylation in human amnion. ScientificWorldJournal 2013; 2013:678156. [PMID: 23533356 PMCID: PMC3590748 DOI: 10.1155/2013/678156] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 12/17/2012] [Indexed: 12/16/2022] Open
Abstract
The amnion is a specialized tissue in contact with the amniotic fluid, which is in a constantly changing state. To investigate the importance of epigenetic events in this tissue in the physiology and pathophysiology of pregnancy, we performed genome-wide DNA methylation profiling of human amnion from term (with and without labor) and preterm deliveries. Using the Illumina Infinium HumanMethylation27 BeadChip, we identified genes exhibiting differential methylation associated with normal labor and preterm birth. Functional analysis of the differentially methylated genes revealed biologically relevant enriched gene sets. Bisulfite sequencing analysis of the promoter region of the oxytocin receptor (OXTR) gene detected two CpG dinucleotides showing significant methylation differences among the three groups of samples. Hypermethylation of the CpG island of the solute carrier family 30 member 3 (SLC30A3) gene in preterm amnion was confirmed by methylation-specific PCR. This work provides preliminary evidence that DNA methylation changes in the amnion may be at least partially involved in the physiological process of labor and the etiology of preterm birth and suggests that DNA methylation profiles, in combination with other biological data, may provide valuable insight into the mechanisms underlying normal and pathological pregnancies.
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Karpinski P, Walter M, Szmida E, Ramsey D, Misiak B, Kozlowska J, Bebenek M, Grzebieniak Z, Blin N, Laczmanski L, Sasiadek MM. Intermediate- and low-methylation epigenotypes do not correspond to CpG island methylator phenotype (low and -zero) in colorectal cancer. Cancer Epidemiol Biomarkers Prev 2012; 22:201-8. [PMID: 23175427 DOI: 10.1158/1055-9965.epi-12-0157] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Most recent genome-wide studies on the CpG island methylation in colorectal cancer (CRC) have led to the discovery of at least 3 distinct methylation clusters. However, there remains an uncertainty whether the CRC clusters identified in these studies represent compatible phenotypes. METHODS We carried out comprehensive genome-scale DNA methylation profiling by Illumina Infinium HumanMethylation27 of 21 DNA pools that represent 84 CRC samples divided according to their high-, intermediate-, and low-methylation epigenotypes (HME, IME, and LME, respectively) and 70 normal-adjacent colonic tissues. We have also examined the relationship among 3 epigenotypes and chromosomal gains and deletions (assessed by Comparative Genomic Hybridization) in a group of 100 CRC samples. RESULTS The HME subgroup showed features associated with CpG island methylator phenotype - high (CIMP-high) including methylation of specific CpG sites (CpGs) as well as significantly lower mean number of chromosomal imbalances when compared with other epigenotypes. The IME subgroup displayed the lowest number of methylated CpGs (717 vs. 2,399 and 2,679 in HME and LME, respectively) and highest mean number of chromosomal imbalances when compared with HME (P, 0.001) and LME (P, 0.004). A comparison between the methylation profiles of 3 epigenotypes revealed more similarities between the HME and LME (1,669 methylated CpGs overlapped) than HME and IME (673 methylated CpGs overlapped). CONCLUSION Our results provide evidence that IME and LME CRCs show opposite features to those that have been previously attributed to CIMP-low and CIMP-0 CRCs. IMPACT These discrepancies should be considered when interpreting the data from a particular epigenotyping method.
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Affiliation(s)
- Pawel Karpinski
- Department of Genetics, Wroclaw Medical University, Poland, Poland.
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Abstract
Bisulfite conversion of genomic DNA differentiates cytosines from 5-methylcytosines and, thus, identifies DNA methylation patterns at the single-base level. Here, we review recent developments incorporating high-throughput sequencing of bisulfite-converted DNA for target-specific analyses and genome-wide mapping of plant and mammalian methylomes. These developments include the analysis of human embryonic stem cell and fetal fibroblast methylomes at single-base resolution, which supports the presence of non-CG DNA methylation in wild-type embryonic stem cells and induced pluripotent stem cells. New developments in nanopore sequencing technologies may lead to directly detecting 5-methylcytosine independently of bisulfite conversion, but the current accuracy of this approach remains a limitation. Furthermore, recent investigations detecting 5-hydroxymethylcytosine within mammalian DNA may add yet another level of complexity to the epigenetic code of the methylome.
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Affiliation(s)
- Jon Reinders
- Department of Plant Biology, University of Geneva, Sciences III, 30 Quai Ernest-Ansermet, Geneva 4, Switzerland
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Martino D, Maksimovic J, Joo JH, Prescott SL, Saffery R. Genome-scale profiling reveals a subset of genes regulated by DNA methylation that program somatic T-cell phenotypes in humans. Genes Immun 2012; 13:388-98. [PMID: 22495533 DOI: 10.1038/gene.2012.7] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The aim of this study was to investigate the dynamics and relationship between DNA methylation and gene expression during early T-cell development. Mononuclear cells were collected at birth and at 12 months from 60 infants and were either activated with anti-CD3 for 24 h or cultured in media alone, and the CD4+ T-cell subset purified. DNA and RNA were co-harvested and DNA methylation was measured in 450 000 CpG sites in parallel with expression measurements taken from 25 000 genes. In unstimulated cells, we found that a subset of 1188 differentially methylated loci were associated with a change in expression in 599 genes (adjusted P value<0.01, β-fold >0.1). These genes were enriched in reprogramming regions of the genome known to control pluripotency. In contrast, over 630 genes were induced following low-level T-cell activation, but this was not associated with any significant change in DNA methylation. We conclude that DNA methylation is dynamic during early T-cell development, and has a role in the consolidation of T-cell-specific gene expression. During the early phase of clonal expansion, DNA methylation is stable and therefore appears to be of limited importance in short-term T-cell responsiveness.
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Affiliation(s)
- D Martino
- Cancer, Disease and Developmental Epigenetics, Murdoch Children's Research Institute, Royal Melbourne Hospital, Parkville, Victoria, Australia
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Salpea P, Russanova VR, Hirai TH, Sourlingas TG, Sekeri-Pataryas KE, Romero R, Epstein J, Howard BH. Postnatal development- and age-related changes in DNA-methylation patterns in the human genome. Nucleic Acids Res 2012; 40:6477-94. [PMID: 22495928 PMCID: PMC3413121 DOI: 10.1093/nar/gks312] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Alterations in DNA methylation have been reported to occur during development and aging; however, much remains to be learned regarding post-natal and age-associated epigenome dynamics, and few if any investigations have compared human methylome patterns on a whole genome basis in cells from newborns and adults. The aim of this study was to reveal genomic regions with distinct structure and sequence characteristics that render them subject to dynamic post-natal developmental remodeling or age-related dysregulation of epigenome structure. DNA samples derived from peripheral blood monocytes and in vitro differentiated dendritic cells were analyzed by methylated DNA Immunoprecipitation (MeDIP) or, for selected loci, bisulfite modification, followed by next generation sequencing. Regions of interest that emerged from the analysis included tandem or interspersed-tandem gene sequence repeats (PCDHG, FAM90A, HRNR, ECEL1P2), and genes with strong homology to other family members elsewhere in the genome (FZD1, FZD7 and FGF17). Our results raise the possibility that selected gene sequences with highly homologous copies may serve to facilitate, perhaps even provide a clock-like function for, developmental and age-related epigenome remodeling. If so, this would represent a fundamental feature of genome architecture in higher eukaryotic organisms.
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Affiliation(s)
- Paraskevi Salpea
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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IDH1 mutation is sufficient to establish the glioma hypermethylator phenotype. Nature 2012; 483:479-83. [PMID: 22343889 DOI: 10.1038/nature10866] [Citation(s) in RCA: 1406] [Impact Index Per Article: 117.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 01/17/2012] [Indexed: 02/07/2023]
Abstract
Both genome-wide genetic and epigenetic alterations are fundamentally important for the development of cancers, but the interdependence of these aberrations is poorly understood. Glioblastomas and other cancers with the CpG island methylator phenotype (CIMP) constitute a subset of tumours with extensive epigenomic aberrations and a distinct biology. Glioma CIMP (G-CIMP) is a powerful determinant of tumour pathogenicity, but the molecular basis of G-CIMP remains unresolved. Here we show that mutation of a single gene, isocitrate dehydrogenase 1 (IDH1), establishes G-CIMP by remodelling the methylome. This remodelling results in reorganization of the methylome and transcriptome. Examination of the epigenome of a large set of intermediate-grade gliomas demonstrates a distinct G-CIMP phenotype that is highly dependent on the presence of IDH mutation. Introduction of mutant IDH1 into primary human astrocytes alters specific histone marks, induces extensive DNA hypermethylation, and reshapes the methylome in a fashion that mirrors the changes observed in G-CIMP-positive lower-grade gliomas. Furthermore, the epigenomic alterations resulting from mutant IDH1 activate key gene expression programs, characterize G-CIMP-positive proneural glioblastomas but not other glioblastomas, and are predictive of improved survival. Our findings demonstrate that IDH mutation is the molecular basis of CIMP in gliomas, provide a framework for understanding oncogenesis in these gliomas, and highlight the interplay between genomic and epigenomic changes in human cancers.
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Hackett CH, Greve L, Novakofski KD, Fortier LA. Comparison of gene-specific DNA methylation patterns in equine induced pluripotent stem cell lines with cells derived from equine adult and fetal tissues. Stem Cells Dev 2011; 21:1803-11. [PMID: 21988203 DOI: 10.1089/scd.2011.0055] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cellular pluripotency is associated with expression of the homeobox transcription factor genes NANOG, SOX2, and POU5F1 (OCT3/4 protein). Some reports suggest that mesenchymal progenitor cells (MPCs) may express increased quantities of these genes, creating the possibility that MPCs are more "pluripotent" than other adult cell types. The objective of this study was to determine whether equine bone marrow-derived MPCs had gene expression or DNA methylation patterns that differed from either early fetal-derived or terminally differentiated adult cells. Specifically, this study compared DNA methylation of the NANOG and SOX2 promoter regions and concurrent gene expression of NANOG, SOX2, and POU5F1 in equine induced pluripotent stem (iPS) cells, fetal fibroblasts, fetal brain cells, adult chondrocytes, and MPCs. Results indicate that NANOG and POU5F1 were not detectable in appreciable quantities in tissues other than the equine iPS cell lines. Equine iPS cells expressed large quantities of all three genes examined. Significantly increased quantities of SOX2 were noted in iPS cells and both fetal-derived cell types compared with adult cells. MPCs and adult chondrocytes expressed equivalent, low quantities of SOX2. Further, NANOG and SOX2 expression inversely correlated with the DNA methylation pattern in the promoter region, such that as gene expression increased, DNA methylation decreased. The equine iPS cell lines examined demonstrated DNA methylation and gene expression patterns that were consistent with pluripotency features described in other species. Results do not support previous reports that NANOG, SOX2, and POU5F1 are poised for increased activity in MPCs compared with other adult cells.
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Affiliation(s)
- Catherine H Hackett
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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Karpinski P, Szmida E, Misiak B, Ramsey D, Leszczynski P, Bebenek M, Sedziak T, Grzebieniak Z, Jonkisz A, Lebioda A, Sasiadek MM. Assessment of three epigenotypes in colorectal cancer by combined bisulfite restriction analysis. Mol Carcinog 2011; 51:1003-8. [PMID: 22006538 DOI: 10.1002/mc.20871] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 09/06/2011] [Accepted: 09/19/2011] [Indexed: 01/17/2023]
Abstract
Recent investigations have demonstrated the clear heterogeneity of sporadic colorectal cancer (CRC) with regard to CpG island methylation. Two unsupervised cluster analyses revealed that CRCs form three distinct DNA methylation subsets, which are referred to as the high-, intermediate-, and low-methylation epigenotypes (HME, IME, and LME, respectively). A recent study by Yagi et al. found a fairly sensitive and specific identification of HME, IME, and LME using two marker panels analyzed by MALDI-TOF mass spectrometry (MassARRAY). However, the expensive equipment required for this method substantially increases the cost and complexity of the assay. In this article, we demonstrate the assessment of HME, IME, and LME in a group of 233 sporadic CRCs using seven markers proposed by Yagi et al. The DNA methylation of each marker was quantified using combined bisulfite restriction analysis (COBRA) and analyzed along with various genetic factors associated with CRC [the BRAF and KRAS mutations, MLH1 methylation and microsatellite instability (MSI)]. The baseline methylation of each marker was generated from pooled DNA isolated from 50 normal colon tissues. We demonstrate that the correlation of HME, IME, and LME epigenotyped by COBRA using different molecular classifiers is similar to that achieved by MassARRAY. Therefore, epigenotyping CRCs using COBRA is a simple, specific, and cost-effective method that has the potential to be widely used in CRC research.
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Affiliation(s)
- Pawel Karpinski
- Department of Genetics; Wroclaw Medical University, Wroclaw, Poland
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Toperoff G, Aran D, Kark JD, Rosenberg M, Dubnikov T, Nissan B, Wainstein J, Friedlander Y, Levy-Lahad E, Glaser B, Hellman A. Genome-wide survey reveals predisposing diabetes type 2-related DNA methylation variations in human peripheral blood. Hum Mol Genet 2011; 21:371-83. [PMID: 21994764 DOI: 10.1093/hmg/ddr472] [Citation(s) in RCA: 271] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Inter-individual DNA methylation variations were frequently hypothesized to alter individual susceptibility to Type 2 Diabetes Mellitus (T2DM). Sequence-influenced methylations were described in T2DM-associated genomic regions, but evidence for direct, sequence-independent association with disease risk is missing. Here, we explore disease-contributing DNA methylation through a stepwise study design: first, a pool-based, genome-scale screen among 1169 case and control individuals revealed an excess of differentially methylated sites in genomic regions that were previously associated with T2DM through genetic studies. Next, in-depth analyses were performed at selected top-ranking regions. A CpG site in the first intron of the FTO gene showed small (3.35%) but significant (P = 0.000021) hypomethylation of cases relative to controls. The effect was independent of the sequence polymorphism in the region and persists among individuals carrying the sequence-risk alleles. The odds of belonging to the T2DM group increased by 6.1% for every 1% decrease in methylation (OR = 1.061, 95% CI: 1.032-1.090), the odds ratio for decrease of 1 standard deviation of methylation (adjusted to gender) was 1.5856 (95% CI: 1.2824-1.9606) and the sensitivity (area under the curve = 0.638, 95% CI: 0.586-0.690; males = 0.675, females = 0.609) was better than that of the strongest known sequence variant. Furthermore, a prospective study in an independent population cohort revealed significant hypomethylation of young individuals that later progressed to T2DM, relative to the individuals who stayed healthy. Further genomic analysis revealed co-localization with gene enhancers and with binding sites for methylation-sensitive transcriptional regulators. The data showed that low methylation level at the analyzed sites is an early marker of T2DM and suggests a novel mechanism by which early-onset, inter-individual methylation variation at isolated non-promoter genomic sites predisposes to T2DM.
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Affiliation(s)
- Gidon Toperoff
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
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Fang F, Turcan S, Rimner A, Kaufman A, Giri D, Morris LGT, Shen R, Seshan V, Mo Q, Heguy A, Baylin SB, Ahuja N, Viale A, Massague J, Norton L, Vahdat LT, Moynahan ME, Chan TA. Breast cancer methylomes establish an epigenomic foundation for metastasis. Sci Transl Med 2011; 3:75ra25. [PMID: 21430268 DOI: 10.1126/scitranslmed.3001875] [Citation(s) in RCA: 214] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cancer-specific alterations in DNA methylation are hallmarks of human malignancies; however, the nature of the breast cancer epigenome and its effects on metastatic behavior remain obscure. To address this issue, we used genome-wide analysis to characterize the methylomes of breast cancers with diverse metastatic behavior. Groups of breast tumors were characterized by the presence or absence of coordinate hypermethylation at a large number of genes, demonstrating a breast CpG island methylator phenotype (B-CIMP). The B-CIMP provided a distinct epigenomic profile and was a strong determinant of metastatic potential. Specifically, the presence of the B-CIMP in tumors was associated with low metastatic risk and survival, and the absence of the B-CIMP was associated with high metastatic risk and death. B-CIMP loci were highly enriched for genes that make up the metastasis transcriptome. Methylation at B-CIMP genes accounted for much of the transcriptomal diversity between breast cancers of varying prognosis, indicating a fundamental epigenomic contribution to metastasis. Comparison of the loci affected by the B-CIMP with those affected by the hypermethylator phenotype in glioma and colon cancer revealed that the CIMP signature was shared by multiple human malignancies. Our data provide a unifying epigenomic framework linking breast cancers with varying outcome and transcriptomic changes underlying metastasis. These findings significantly enhance our understanding of breast cancer oncogenesis and aid the development of new prognostic biomarkers for this common malignancy.
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Affiliation(s)
- Fang Fang
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
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Kober P, Bujko M, Olędzki J, Tysarowski A, Siedlecki JA. Methyl-CpG binding column-based identification of nine genes hypermethylated in colorectal cancer. Mol Carcinog 2011; 50:846-56. [PMID: 21438024 DOI: 10.1002/mc.20763] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 01/20/2011] [Accepted: 02/04/2011] [Indexed: 12/19/2022]
Abstract
DNA methylation is an epigenetic event that plays a role in gene expression regulation. Alterations in DNA methylation contribute to cancer development and progression. The aim of this study was to identify gene promoters aberrantly methylated in colorectal tumor tissue in comparison to normal colonic mucosa. Analyses were performed on two pooled DNA samples: from normal and cancerous tissue obtained from CRC patients. DNA was fractionated according to methylation degree with the use of affinity column containing methyl-CpG binding domain. To identify novel hypermethylated gene promoters, methylated DNA from normal and from cancerous tissues were analyzed with the use of promoter microarrays. We identified nine novel genes hypermethylated in colorectal cancer. The frequency of their promoter methylation was assessed in the larger group of patients (n = 77): KCNK12 (methylated in 41% of CRC patients), GPR101 (40%), CDH2 (45%), BARX1 (56%), CNTFR (22%), SYT6 (64%), SMO (21%), EPHA5 (43%), and GSPT2 (21%). The results of gene expression level analysis suggest the role of promoter methylation in downregulation of six out of nine genes examined. We did not find correlation between gene methylation and age, gender, tumor grade or stage. Importantly, in stage IV CRC methylation of GPR101 correlated with longer time to progression (P = 0.0042; HR = 2.5468; 95% CI 1.5391-10.0708).
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Affiliation(s)
- Paulina Kober
- Department of Molecular Biology, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
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Finer S, Holland ML, Nanty L, Rakyan VK. The hunt for the epiallele. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2011; 52:1-11. [PMID: 20839222 DOI: 10.1002/em.20590] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Understanding the origin of phenotypic variation remains one of the principle challenges of contemporary biology. Recent genome-wide association studies have identified association between common genetic variants and complex phenotype; however, the minimal effect sizes observed in such studies highlight the potential for other causal factors to be involved in phenotypic variation. The epigenetic state of an organism (or 'epigenome') incorporates a landscape of complex and plastic molecular events that may underlie the 'missing link' that integrates genotype with phenotype. The nature of these processes has been the subject of intense scientific study over the recent years, and characterisation of epigenetic variation, in the form of 'epialleles', is providing fascinating insight into how the genome functions within a range of developmental processes, environments, and in states of health and disease. This review will discuss how and when mammalian epialleles may be generated and their interaction with genetic and environmental factors. We will outline how an epiallele has a variable relationship with phenotype, and how new technologies may be used for their detection and to facilitate an understanding of their contribution to phenotype. Finally, we will consider epialleles in population variation and their teleological role in evolution. variation and their teleological role in evolution.
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Affiliation(s)
- Sarah Finer
- The Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, United Kingdom
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DNA methylation profiling using bisulfite-based epityping of pooled genomic DNA. Methods 2010; 52:255-8. [DOI: 10.1016/j.ymeth.2010.06.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 06/24/2010] [Accepted: 06/25/2010] [Indexed: 12/16/2022] Open
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Wong CCY, Caspi A, Williams B, Craig IW, Houts R, Ambler A, Moffitt TE, Mill J. A longitudinal study of epigenetic variation in twins. Epigenetics 2010; 5:516-26. [PMID: 20505345 DOI: 10.4161/epi.5.6.12226] [Citation(s) in RCA: 210] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
DNA methylation is a key epigenetic mechanism involved in the developmental regulation of gene expression. Alterations in DNA methylation are established contributors to inter-individual phenotypic variation and have been associated with disease susceptibility. The degree to which changes in loci-specific DNA methylation are under the influence of heritable and environmental factors is largely unknown. In this study, we quantitatively measured DNA methylation across the promoter regions of the dopamine receptor 4 gene (DRD4), the serotonin transporter gene (SLC6A4/SERT) and the X-linked monoamine oxidase A gene (MAOA) using DNA sampled at both ages 5 and 10 years in 46 MZ twin-pairs and 45 DZ twin-pairs (total n=182). Our data suggest that DNA methylation differences are apparent already in early childhood, even between genetically identical individuals, and that individual differences in methylation are not stable over time. Our longitudinal-developmental study suggests that environmental influences are important factors accounting for interindividual DNA methylation differences, and that these influences differ across the genome. The observation of dynamic changes in DNA methylation over time highlights the importance of longitudinal research designs for epigenetic research.
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Affiliation(s)
- Chloe Chung Yi Wong
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, UK.
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Laird PW. Principles and challenges of genome-wide DNA methylation analysis. Nat Rev Genet 2010; 11:191-203. [DOI: 10.1038/nrg2732] [Citation(s) in RCA: 1067] [Impact Index Per Article: 76.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Dehan P, Kustermans G, Guenin S, Horion J, Boniver J, Delvenne P. DNA methylation and cancer diagnosis: new methods and applications. Expert Rev Mol Diagn 2009; 9:651-7. [PMID: 19817550 DOI: 10.1586/erm.09.53] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Methylation of cytosines in cytosine-guanine (CpG) dinucleotides is one of the most important epigenetic alterations in animals. The presence of methylcytosine in the promoter of specific genes has profound consequences on local chromatin structure and on the regulation of gene expression. Changes in DNA methylation play a central role in carcinogenesis. Hypermethylation and consecutive transcriptional silencing of tumor-suppressor genes has been documented in numerous cancers. The identification of target genes silenced by this modification has a great impact on diagnosis, classification, definition of risk groups and prognosis of cancer patients. Here we outline genome-wide techniques aiming at the identification of relevant methylated promoters. Methods and applications allowing clinicians to monitor the methylation of target genes will be also reviewed.
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Affiliation(s)
- Pierre Dehan
- Experimental Pathology, University of Liege, CHU Sart-Tilman, Boulevard de l'Hopital, 4000 Liege, Belgium.
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Craig JE, Hewitt AW, McMellon AE, Henders AK, Ma L, Wallace L, Sharma S, Burdon KP, Visscher PM, Montgomery GW, MacGregor S. Rapid inexpensive genome-wide association using pooled whole blood. Genome Res 2009; 19:2075-80. [PMID: 19801603 DOI: 10.1101/gr.094680.109] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Genome-wide association studies (GWAS) have now successfully identified important genetic variants associated with many human traits and diseases. The high cost of genotyping arrays in large data sets remains the major barrier to wider utilization of GWAS. We have developed a novel method in which whole blood from cases and controls, respectively, is pooled prior to DNA extraction for genotyping. We demonstrate proof of principle by clearly identifying the associated variants for eye color, age-related macular degeneration, and pseudoexfoliation syndrome in cohorts not previously studied. Blood pooling has the potential to reduce GWAS cost by several orders of magnitude and dramatically shorten gene discovery time. This method has profound implications for translation of modern genetic approaches to a multitude of diseases and traits yet to be analyzed by GWAS, and will enable developing nations to participate in GWAS.
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Affiliation(s)
- Jamie E Craig
- Department of Ophthalmology, Flinders University, Adelaide SA 5042, Australia.
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