1
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Baker EC, San AE, Cilkiz KZ, Littlejohn BP, Cardoso RC, Ghaffari N, Long CR, Riggs PK, Randel RD, Welsh TH, Riley DG. Inter-Individual Variation in DNA Methylation Patterns across Two Tissues and Leukocytes in Mature Brahman Cattle. BIOLOGY 2023; 12:biology12020252. [PMID: 36829529 PMCID: PMC9953534 DOI: 10.3390/biology12020252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023]
Abstract
Quantifying the natural inter-individual variation in DNA methylation patterns is important for identifying its contribution to phenotypic variation, but also for understanding how the environment affects variability, and for incorporation into statistical analyses. The inter-individual variation in DNA methylation patterns in female cattle and the effect that a prenatal stressor has on such variability have yet to be quantified. Thus, the objective of this study was to utilize methylation data from mature Brahman females to quantify the inter-individual variation in DNA methylation. Pregnant Brahman cows were transported for 2 h durations at days 60 ± 5; 80 ± 5; 100 ± 5; 120 ± 5; and 140 ± 5 of gestation. A non-transport group was maintained as a control. Leukocytes, amygdala, and anterior pituitary glands were harvested from eight cows born from the non-transport group (Control) and six from the transport group (PNS) at 5 years of age. The DNA harvested from the anterior pituitary contained the greatest variability in DNA methylation of cytosine-phosphate-guanine (mCpG) sites from both the PNS and Control groups, and the amygdala had the least. Numerous variable mCpG sites were associated with retrotransposable elements and highly repetitive regions of the genome. Some of the genomic features that had high variation in DNA methylation are involved in immune responses, signaling, responses to stimuli, and metabolic processes. The small overlap of highly variable CpG sites and features between tissues and leukocytes supports the role of variable DNA methylation in regulating tissue-specific gene expression. Many of the CpG sites that exhibited high variability in DNA methylation were common between the PNS and Control groups within a tissue, but there was little overlap in genomic features with high variability. The interaction between the prenatal environment and the genome could be responsible for the differences in location of the variable DNA methylation.
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Affiliation(s)
- Emilie C. Baker
- Department of Animal Science, Texas A&M University, College Station, TX 77845, USA
| | - Audrey E. San
- Department of Animal Science, Texas A&M University, College Station, TX 77845, USA
- Texas A&M AgriLife Research, College Station, TX 77845, USA
- Texas A&M AgriLife Research & Extension Center at Overton, Overton, TX 75684, USA
| | - Kubra Z. Cilkiz
- Department of Animal Science, Texas A&M University, College Station, TX 77845, USA
| | - Brittni P. Littlejohn
- Department of Animal Science, Texas A&M University, College Station, TX 77845, USA
- Texas A&M AgriLife Research & Extension Center at Overton, Overton, TX 75684, USA
| | - Rodolfo C. Cardoso
- Department of Animal Science, Texas A&M University, College Station, TX 77845, USA
| | - Noushin Ghaffari
- Department of Computer Science, Prairie View A&M University, Prairie View, TX 77446, USA
| | - Charles R. Long
- Department of Animal Science, Texas A&M University, College Station, TX 77845, USA
- Texas A&M AgriLife Research & Extension Center at Overton, Overton, TX 75684, USA
| | - Penny K. Riggs
- Department of Animal Science, Texas A&M University, College Station, TX 77845, USA
| | - Ronald D. Randel
- Department of Animal Science, Texas A&M University, College Station, TX 77845, USA
- Texas A&M AgriLife Research & Extension Center at Overton, Overton, TX 75684, USA
| | - Thomas H. Welsh
- Department of Animal Science, Texas A&M University, College Station, TX 77845, USA
- Texas A&M AgriLife Research, College Station, TX 77845, USA
| | - David G. Riley
- Department of Animal Science, Texas A&M University, College Station, TX 77845, USA
- Correspondence:
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2
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Lang AL, Eulalio T, Fox E, Yakabi K, Bukhari SA, Kawas CH, Corrada MM, Montgomery SB, Heppner FL, Capper D, Nachun D, Montine TJ. Methylation differences in Alzheimer's disease neuropathologic change in the aged human brain. Acta Neuropathol Commun 2022; 10:174. [PMID: 36447297 PMCID: PMC9710143 DOI: 10.1186/s40478-022-01470-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 10/24/2022] [Indexed: 12/05/2022] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia with advancing age as its strongest risk factor. AD neuropathologic change (ADNC) is known to be associated with numerous DNA methylation changes in the human brain, but the oldest old (> 90 years) have so far been underrepresented in epigenetic studies of ADNC. Our study participants were individuals aged over 90 years (n = 47) from The 90+ Study. We analyzed DNA methylation from bulk samples in eight precisely dissected regions of the human brain: middle frontal gyrus, cingulate gyrus, entorhinal cortex, dentate gyrus, CA1, substantia nigra, locus coeruleus and cerebellar cortex. We deconvolved our bulk data into cell-type-specific (CTS) signals using computational methods. CTS methylation differences were analyzed across different levels of ADNC. The highest amount of ADNC related methylation differences was found in the dentate gyrus, a region that has so far been underrepresented in large scale multi-omic studies. In neurons of the dentate gyrus, DNA methylation significantly differed with increased burden of amyloid beta (Aβ) plaques at 5897 promoter regions of protein-coding genes. Amongst these, higher Aβ plaque burden was associated with promoter hypomethylation of the Presenilin enhancer 2 (PEN-2) gene, one of the rate limiting genes in the formation of gamma-secretase, a multicomponent complex that is responsible in part for the endoproteolytic cleavage of amyloid precursor protein into Aβ peptides. In addition to novel ADNC related DNA methylation changes, we present the most detailed array-based methylation survey of the old aged human brain to date. Our open-sourced dataset can serve as a brain region reference panel for future studies and help advance research in aging and neurodegenerative diseases.
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Affiliation(s)
- Anna-Lena Lang
- Department of Neuropathology, Charité–Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Tiffany Eulalio
- Department of Biomedical Data Science, Stanford University, Stanford, CA 94305 USA
| | - Eddie Fox
- Department of Pathology, Stanford University, 300 Pasteur Drive, Stanford, CA 94305 USA
| | - Koya Yakabi
- Department of Pathology, Stanford University, 300 Pasteur Drive, Stanford, CA 94305 USA
| | - Syed A. Bukhari
- Department of Pathology, Stanford University, 300 Pasteur Drive, Stanford, CA 94305 USA
| | - Claudia H. Kawas
- Department of Neurology, University of California Irvine, Orange, CA 92868-4280 USA
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697 USA
| | - Maria M. Corrada
- Department of Neurology, University of California Irvine, Orange, CA 92868-4280 USA
- Department of Epidemiology, University of California, Irvine, CA 92617 USA
| | - Stephen B. Montgomery
- Department of Pathology, Stanford University, 300 Pasteur Drive, Stanford, CA 94305 USA
- Department of Genetics, Stanford University, Stanford, CA 94305 USA
- Department of Biomedical Data Science, Stanford University, Stanford, CA 94305 USA
| | - Frank L. Heppner
- Department of Neuropathology, Charité–Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Charitéplatz 1, 10117 Berlin, Germany
- German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
- Cluster of Excellence, NeuroCure, 10117 Berlin, Germany
| | - David Capper
- Department of Neuropathology, Charité–Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Daniel Nachun
- Department of Genetics, Stanford University, Stanford, CA 94305 USA
| | - Thomas J. Montine
- Department of Pathology, Stanford University, 300 Pasteur Drive, Stanford, CA 94305 USA
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3
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Panov J, Kaphzan H. An Association Study of DNA Methylation and Gene Expression in Angelman Syndrome: A Bioinformatics Approach. Int J Mol Sci 2022; 23:ijms23169139. [PMID: 36012404 PMCID: PMC9409443 DOI: 10.3390/ijms23169139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 07/27/2022] [Accepted: 08/05/2022] [Indexed: 12/01/2022] Open
Abstract
Angelman syndrome (AS) is a neurodevelopmental disorder caused by the loss of function of the E3-ligase UBE3A. Despite multiple studies, AS pathophysiology is still obscure and has mostly been explored in rodent models of the disease. In recent years, a growing body of studies has utilized omics datasets in the attempt to focus research regarding the pathophysiology of AS. Here, for the first time, we utilized a multi-omics approach at the epigenomic level and the transcriptome level, for human-derived neurons. Using publicly available datasets for DNA methylation and gene expression, we found genome regions in proximity to gene promoters and intersecting with gene-body regions that were differentially methylated and differentially expressed in AS. We found that overall, the genome in AS postmortem brain tissue was hypo-methylated compared to healthy controls. We also found more upregulated genes than downregulated genes in AS. Many of these dysregulated genes in neurons obtained from AS patients are known to be critical for neuronal development and synaptic functioning. Taken together, our results suggest a list of dysregulated genes that may be involved in AS development and its pathological features. Moreover, these genes might also have a role in neurodevelopmental disorders similar to AS.
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4
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Pfeiffer JR, van Rooij SJH, Mekawi Y, Fani N, Jovanovic T, Michopoulos V, Smith AK, Stevens JS, Uddin M. Blood-derived deoxyribonucleic acid methylation clusters associate with adverse social exposures and endophenotypes of stress-related psychiatric illness in a trauma-exposed cohort of women. Front Psychiatry 2022; 13:892302. [PMID: 36405926 PMCID: PMC9668877 DOI: 10.3389/fpsyt.2022.892302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 09/21/2022] [Indexed: 11/06/2022] Open
Abstract
Adverse social exposures (ASEs) such as low income, low educational attainment, and childhood/adult trauma exposure are associated with variability in brain region measurements of gray matter volume (GMV), surface area (SA), and cortical thickness (CT). These CNS morphometries are associated with stress-related psychiatric illnesses and represent endophenotypes of stress-related psychiatric illness development. Epigenetic mechanisms, such as 5-methyl-cytosine (5mC), may contribute to the biological embedding of the environment but are understudied and not well understood. How 5mC relates to CNS endophenotypes of psychiatric illness is also unclear. In 97 female, African American, trauma-exposed participants from the Grady Trauma Project, we examined the associations of childhood trauma burden (CTQ), adult trauma burden, low income, and low education with blood-derived 5mC clusters and variability in brain region measurements in the amygdala, hippocampus, and frontal cortex subregions. To elucidate whether peripheral 5mC indexes central nervous system (CNS) endophenotypes of psychiatric illness, we tested whether 73 brain/blood correlated 5mC clusters, defined by networks of correlated 5mC probes measured on Illumina's HumanMethylation Epic Beadchip, mediated the relationship between ASEs and brain measurements. CTQ was negatively associated with rostral middle frontal gyrus (RMFG) SA (β =-0.231, p = 0.041). Low income and low education were also associated with SA or CT in a number of brain regions. Seven 5mC clusters were associated with CTQ (pmin = 0.002), two with low education (pmin = 0.010), and three with low income (pmin = 0.007). Two clusters fully mediated the relation between CTQ and RMFG SA, accounting for 47 and 35% of variability, respectively. These clusters were enriched for probes falling in DNA regulatory regions, as well as signal transduction and immune signaling gene ontology functions. Methylome-network analyses showed enrichment of macrophage migration (p = 9 × 10-8), T cell receptor complex (p = 6 × 10-6), and chemokine-mediated signaling (p = 7 × 10-4) pathway enrichment in association with CTQ. Our results support prior work highlighting brain region variability associated with ASEs, while informing a peripheral inflammation-based epigenetic mechanism of biological embedding of such exposures. These findings could also serve to potentiate increased investigation of understudied populations at elevated risk for stress-related psychiatric illness development.
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Affiliation(s)
- John R Pfeiffer
- Department of Psychology, University of Illinois at Urbana-Champaign, Urbana, IL, United States.,Carl R. Woese Institute for Genomic Biology, Urbana, IL, United States
| | - Sanne J H van Rooij
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States
| | - Yara Mekawi
- Department of Psychological and Brain Sciences, University of Louisville, Louisville, KY, United States
| | - Negar Fani
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States
| | - Tanja Jovanovic
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University, Detroit, MI, United States
| | - Vasiliki Michopoulos
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States
| | - Alicia K Smith
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States.,Department of Gynecology and Obstetrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Jennifer S Stevens
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States
| | - Monica Uddin
- Genomics Program, College of Public Health, University of South Florida, Tampa, FL, United States
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5
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Ehrlich KC, Baribault C, Ehrlich M. Epigenetics of Muscle- and Brain-Specific Expression of KLHL Family Genes. Int J Mol Sci 2020; 21:E8394. [PMID: 33182325 PMCID: PMC7672584 DOI: 10.3390/ijms21218394] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/02/2020] [Accepted: 11/06/2020] [Indexed: 02/07/2023] Open
Abstract
KLHL and the related KBTBD genes encode components of the Cullin-E3 ubiquitin ligase complex and typically target tissue-specific proteins for degradation, thereby affecting differentiation, homeostasis, metabolism, cell signaling, and the oxidative stress response. Despite their importance in cell function and disease (especially, KLHL40, KLHL41, KBTBD13, KEAP1, and ENC1), previous studies of epigenetic factors that affect transcription were predominantly limited to promoter DNA methylation. Using diverse tissue and cell culture whole-genome profiles, we examined 17 KLHL or KBTBD genes preferentially expressed in skeletal muscle or brain to identify tissue-specific enhancer and promoter chromatin, open chromatin (DNaseI hypersensitivity), and DNA hypomethylation. Sixteen of the 17 genes displayed muscle- or brain-specific enhancer chromatin in their gene bodies, and most exhibited specific intergenic enhancer chromatin as well. Seven genes were embedded in super-enhancers (particularly strong, tissue-specific clusters of enhancers). The enhancer chromatin regions typically displayed foci of DNA hypomethylation at peaks of open chromatin. In addition, we found evidence for an intragenic enhancer in one gene upregulating expression of its neighboring gene, specifically for KLHL40/HHATL and KLHL38/FBXO32 gene pairs. Many KLHL/KBTBD genes had tissue-specific promoter chromatin at their 5' ends, but surprisingly, two (KBTBD11 and KLHL31) had constitutively unmethylated promoter chromatin in their 3' exons that overlaps a retrotransposed KLHL gene. Our findings demonstrate the importance of expanding epigenetic analyses beyond the 5' ends of genes in studies of normal and abnormal gene regulation.
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Affiliation(s)
- Kenneth C. Ehrlich
- Center for Biomedical Informatics and Genomics, Tulane University Health Sciences Center, New Orleans, LA 70112, USA;
| | - Carl Baribault
- Center for Research and Scientific Computing (CRSC), Tulane University Information Technology, Tulane University, New Orleans, LA 70112, USA;
| | - Melanie Ehrlich
- Center for Biomedical Informatics and Genomics, Tulane Cancer Center, Hayward Genetics Program, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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6
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Reynolds RH, Hardy J, Ryten M, Gagliano Taliun SA. Informing disease modelling with brain-relevant functional genomic annotations. Brain 2019; 142:3694-3712. [PMID: 31603214 PMCID: PMC6885670 DOI: 10.1093/brain/awz295] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 07/05/2019] [Accepted: 07/29/2019] [Indexed: 12/13/2022] Open
Abstract
The past decade has seen a surge in the number of disease/trait-associated variants, largely because of the union of studies to share genetic data and the availability of electronic health records from large cohorts for research use. Variant discovery for neurological and neuropsychiatric genome-wide association studies, including schizophrenia, Parkinson's disease and Alzheimer's disease, has greatly benefitted; however, the translation of these genetic association results to interpretable biological mechanisms and models is lagging. Interpreting disease-associated variants requires knowledge of gene regulatory mechanisms and computational tools that permit integration of this knowledge with genome-wide association study results. Here, we summarize key conceptual advances in the generation of brain-relevant functional genomic annotations and amongst tools that allow integration of these annotations with association summary statistics, which together provide a new and exciting opportunity to identify disease-relevant genes, pathways and cell types in silico. We discuss the opportunities and challenges associated with these developments and conclude with our perspective on future advances in annotation generation, tool development and the union of the two.
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Affiliation(s)
- Regina H Reynolds
- Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London, UK
| | - John Hardy
- Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London, UK
- UK Dementia Research Institute at University College London (UCL), London, UK
| | - Mina Ryten
- Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London, UK
| | - Sarah A Gagliano Taliun
- Center for Statistical Genetics and Department of Biostatistics, University of Michigan, Ann Arbor, Michigan, USA
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7
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Fila M, Chojnacki C, Chojnacki J, Blasiak J. Is an "Epigenetic Diet" for Migraines Justified? The Case of Folate and DNA Methylation. Nutrients 2019; 11:nu11112763. [PMID: 31739474 PMCID: PMC6893742 DOI: 10.3390/nu11112763] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/05/2019] [Accepted: 11/12/2019] [Indexed: 12/15/2022] Open
Abstract
Migraines are a common disease with limited treatment options and some dietary factors are recognized to trigger headaches. Although migraine pathogenesis is not completely known, aberrant DNA methylation has been reported to be associated with its occurrence. Folate, an essential micronutrient involved in one-carbon metabolism and DNA methylation, was shown to have beneficial effects on migraines. Moreover, the variability of the methylenetetrahydrofolate reductase gene, important in both folate metabolism and migraine pathogenesis, modulates the beneficial effects of folate for migraines. Therefore, migraine could be targeted by a folate-rich, DNA methylation-directed diet, but there are no data showing that beneficial effects of folate consumption result from its epigenetic action. Furthermore, contrary to epigenetic drugs, epigenetic diets contain many compounds, some yet unidentified, with poorly known or completely unknown potential to interfere with the epigenetic action of the main dietary components. The application of epigenetic diets for migraines and other diseases requires its personalization to the epigenetic profile of a patient, which is largely unknown. Results obtained so far do not warrant the recommendation of any epigenetic diet as effective in migraine prevention and therapy. Further studies including a folate-rich diet fortified with valproic acid, another modifier of epigenetic profile effective in migraine prophylaxis, may help to clarify this issue.
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Affiliation(s)
- Michal Fila
- Department of Neurology, Polish Mother Memorial Hospital, Research Institute, 93-338 Lodz, Poland;
| | - Cezary Chojnacki
- Department of Clinical Nutrition and Gastroenterological Diagnostics, Medical University of Lodz, 90-647 Lodz, Poland; (C.C.); (J.C.)
| | - Jan Chojnacki
- Department of Clinical Nutrition and Gastroenterological Diagnostics, Medical University of Lodz, 90-647 Lodz, Poland; (C.C.); (J.C.)
| | - Janusz Blasiak
- Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland
- Correspondence: ; Tel.: +48-426-354-334
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8
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Li J, Wang GZ. Application of Computational Biology to Decode Brain Transcriptomes. GENOMICS PROTEOMICS & BIOINFORMATICS 2019; 17:367-380. [PMID: 31655213 PMCID: PMC6943780 DOI: 10.1016/j.gpb.2019.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 02/21/2019] [Accepted: 03/15/2019] [Indexed: 01/03/2023]
Abstract
The rapid development of high-throughput sequencing technologies has generated massive valuable brain transcriptome atlases, providing great opportunities for systematically investigating gene expression characteristics across various brain regions throughout a series of developmental stages. Recent studies have revealed that the transcriptional architecture is the key to interpreting the molecular mechanisms of brain complexity. However, our knowledge of brain transcriptional characteristics remains very limited. With the immense efforts to generate high-quality brain transcriptome atlases, new computational approaches to analyze these high-dimensional multivariate data are greatly needed. In this review, we summarize some public resources for brain transcriptome atlases and discuss the general computational pipelines that are commonly used in this field, which would aid in making new discoveries in brain development and disorders.
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Affiliation(s)
- Jie Li
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guang-Zhong Wang
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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9
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Lim WJ, Kim KH, Kim JY, Kim HJ, Kim M, Park JL, Yoon S, Oh JH, Cho JW, Kim YS, Kim N. Investigation of Gene Expression and DNA Methylation From Seven Different Brain Regions of a Crab-Eating Monkey as Determined by RNA-Seq and Whole-Genome Bisulfite Sequencing. Front Genet 2019; 10:694. [PMID: 31428131 PMCID: PMC6690020 DOI: 10.3389/fgene.2019.00694] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/02/2019] [Indexed: 01/04/2023] Open
Abstract
The crab-eating monkey is widely used in biomedical research for pharmacological experiments. Epigenetic regulation in the brain regions of primates involves complex patterns of DNA methylation. Previous studies of methylated CpG-binding domains using microarray technology or peak identification of sequence reads mostly focused on developmental stages or disease, rather than normal brains. To identify correlations between gene expression and DNA methylation levels that may be related to transcriptional regulation, we generated RNA-seq and whole-genome bisulfite sequencing data from seven different brain regions from a single crab-eating monkey. We identified 92 genes whose expression levels were significantly correlated, positively or negatively, with DNA methylation levels. Among them, 11 genes exhibited brain region-specific characteristics, and their expression patterns were strongly correlated with DNA methylation level. Nine genes (SLC2A5, MCM5, DRAM1, TTC12, DHX40, COR01A, LRAT, FLVCR2, and PTER) had effects on brain and eye function and development, and two (LHX6 and MEST) were previously identified as genes in which DNA methylation levels change significantly in the promoter region and are therefore considered brain epigenetic markers. Furthermore, we characterized DNA methylation of repetitive elements at the whole genome through repeat annotation at single-base resolution. Our results reveal the diverse roles of DNA methylation at single-base resolution throughout the genome and reflect the epigenetic variations in adult brain tissues.
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Affiliation(s)
- Won-Jun Lim
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea.,Department of Bioinformatics, KRIBB School of Bioscience, University of Science and Technology (UST), Daejeon, South Korea
| | - Kyoung Hyoun Kim
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea.,Department of Bioinformatics, KRIBB School of Bioscience, University of Science and Technology (UST), Daejeon, South Korea
| | - Jae-Yoon Kim
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea.,Department of Bioinformatics, KRIBB School of Bioscience, University of Science and Technology (UST), Daejeon, South Korea
| | - Hee-Jin Kim
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
| | - Mirang Kim
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
| | - Jong-Lyul Park
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
| | - Seokjoo Yoon
- Predictive Toxicity Department, Korea Institute of Toxicology (KIT), Daejeon, South Korea
| | - Jung-Hwa Oh
- Predictive Toxicity Department, Korea Institute of Toxicology (KIT), Daejeon, South Korea
| | - Jae-Woo Cho
- Predictive Toxicity Department, Korea Institute of Toxicology (KIT), Daejeon, South Korea
| | - Yong Sung Kim
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
| | - Namshin Kim
- Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea.,Department of Bioinformatics, KRIBB School of Bioscience, University of Science and Technology (UST), Daejeon, South Korea
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10
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Rizzardi LF, Hickey PF, Rodriguez DiBlasi V, Tryggvadóttir R, Callahan CM, Idrizi A, Hansen KD, Feinberg AP. Neuronal brain-region-specific DNA methylation and chromatin accessibility are associated with neuropsychiatric trait heritability. Nat Neurosci 2019; 22:307-316. [PMID: 30643296 PMCID: PMC6348048 DOI: 10.1038/s41593-018-0297-8] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 11/13/2018] [Indexed: 12/21/2022]
Abstract
Epigenetic modifications confer stable transcriptional patterns in the brain and both normal and abnormal brain function involve specialized brain regions. We examined DNA methylation by whole genome bisulfite sequencing in neuronal and non-neuronal populations from four brain regions (anterior cingulate gyrus, hippocampus, prefrontal cortex, and nucleus accumbens) as well as chromatin accessibility in the latter two. We find pronounced differences in CpG and non-CpG differentially methylated regions (CG- and CH-DMRs) only in neuronal cells across regions. While neuronal CH-DMRs were highly associated with differential gene expression, CG-DMRs were consistent with chromatin accessibility and enriched for regulatory regions. These CG-DMRs comprise ~12 Mb of the genome that is highly enriched for genomic regions associated with heritability of neuropsychiatric traits including addictive behavior, schizophrenia, and neuroticism, suggesting a mechanistic link between pathology and differential neuron-specific epigenetic regulation in distinct brain regions.
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Affiliation(s)
- Lindsay F Rizzardi
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter F Hickey
- Department of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Varenka Rodriguez DiBlasi
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rakel Tryggvadóttir
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Colin M Callahan
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Adrian Idrizi
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kasper D Hansen
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,Department of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA. .,McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Andrew P Feinberg
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,Department of Biomedical Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA. .,Department of Mental Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
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11
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McCormick H, Young PE, Hur SSJ, Booher K, Chung H, Cropley JE, Giannoulatou E, Suter CM. Isogenic mice exhibit sexually-dimorphic DNA methylation patterns across multiple tissues. BMC Genomics 2017; 18:966. [PMID: 29237414 PMCID: PMC5729250 DOI: 10.1186/s12864-017-4350-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 11/27/2017] [Indexed: 12/20/2022] Open
Abstract
Background Cytosine methylation is a stable epigenetic modification of DNA that plays an important role in both normal physiology and disease. Most diseases exhibit some degree of sexual dimorphism, but the extent to which epigenetic states are influenced by sex is understudied and poorly understood. To address this deficit we studied DNA methylation patterns across multiple reduced representation bisulphite sequencing datasets (from liver, heart, brain, muscle and spleen) derived from isogenic male and female mice. Results DNA methylation patterns varied significantly from tissue to tissue, as expected, but they also varied between the sexes, with thousands of sexually dimorphic loci identified. The loci affected were largely autonomous to each tissue, even within tissues derived from the same germ layer. At most loci, differences between genders were driven by females exhibiting hypermethylation relative to males; a proportion of these differences were independent of the presence of testosterone in males. Loci harbouring gender differences were clustered in ontologies related to tissue function. Conclusions Our findings suggest that gender is underwritten in the epigenome in a tissue-specific and potentially sex hormone-independent manner. Gender-specific epigenetic states are likely to have important implications for understanding sexually dimorphic phenotypes in health and disease. Electronic supplementary material The online version of this article (doi: 10.1186/s12864-017-4350-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Helen McCormick
- Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia.,St Vincents Clinical School, Faculty of Medicine, University of New South Wales, Kensington, NSW, 2052, Australia
| | - Paul E Young
- Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia
| | - Suzy S J Hur
- Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia
| | - Keith Booher
- Zymo Research, Murphy Ave, Irvine, CA, 92614, USA
| | - Hunter Chung
- Zymo Research, Murphy Ave, Irvine, CA, 92614, USA
| | - Jennifer E Cropley
- Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia.,St Vincents Clinical School, Faculty of Medicine, University of New South Wales, Kensington, NSW, 2052, Australia
| | - Eleni Giannoulatou
- Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia. .,St Vincents Clinical School, Faculty of Medicine, University of New South Wales, Kensington, NSW, 2052, Australia.
| | - Catherine M Suter
- Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia. .,St Vincents Clinical School, Faculty of Medicine, University of New South Wales, Kensington, NSW, 2052, Australia.
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12
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Zhubi A, Chen Y, Guidotti A, Grayson DR. Epigenetic regulation of RELN and GAD1 in the frontal cortex (FC) of autism spectrum disorder (ASD) subjects. Int J Dev Neurosci 2017; 62:63-72. [PMID: 28229923 PMCID: PMC5575980 DOI: 10.1016/j.ijdevneu.2017.02.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 02/08/2017] [Accepted: 02/09/2017] [Indexed: 01/01/2023] Open
Abstract
Both Reelin (RELN) and glutamate decarboxylase 67 (GAD1) have been implicated in the pathophysiology of Autism Spectrum Disorders (ASD). We have previously shown that both mRNAs are reduced in the cerebella (CB) of ASD subjects through a mechanism that involves increases in the amounts of MECP2 binding to the corresponding promoters. In the current study, we examined the expression of RELN, GAD1, GAD2, and several other mRNAs implicated in this disorder in the frontal cortices (FC) of ASD and CON subjects. We also focused on the role that epigenetic processes play in the regulation of these genes in ASD brain. Our goal is to better understand the molecular basis for the down-regulation of genes expressed in GABAergic neurons in ASD brains. We measured mRNA levels corresponding to selected GABAergic genes using qRT-PCR in RNA isolated from both ASD and CON groups. We determined the extent of binding of MECP2 and DNMT1 repressor proteins by chromatin immunoprecipitation (ChIP) assays. The amount of 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) present in the promoters of the target genes was quantified by methyl DNA immunoprecipitation (MeDIP) and hydroxyl MeDIP (hMeDIP). We detected significant reductions in the mRNAs associated with RELN and GAD1 and significant increases in mRNAs encoding the Ten-eleven Translocation (TET) enzymes 1, 2, and 3. We also detected increased MECP2 and DNMT1 binding to the corresponding promoter regions of GAD1, RELN, and GAD2. Interestingly, there were decreased amounts of 5mC at both promoters and little change in 5hmC content in these same DNA fragments. Our data demonstrate that RELN, GAD1, and several other genes selectively expressed in GABAergic neurons, are down-regulated in post-mortem ASD FC. In addition, we observed increased DNMT1 and MECP2 binding at the corresponding promoters of these genes. The finding of increased MECP2 binding to the RELN, GAD1 and GAD2 promoters, with reduced amounts of 5mC and unchanged amounts of 5hmC present in these regions, suggests the possibility that DNMT1 interacts with and alters MECP2 binding properties to selected promoters. Comparisons between data obtained from the FC with CB studies showed some common themes between brain regions which are discussed.
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Affiliation(s)
- Adrian Zhubi
- The Psychiatric Institute, Center for Alcohol Research in Epigenetics, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, United States.
| | - Ying Chen
- The Psychiatric Institute, Center for Alcohol Research in Epigenetics, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, United States.
| | - Alessandro Guidotti
- The Psychiatric Institute, Center for Alcohol Research in Epigenetics, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, United States.
| | - Dennis R Grayson
- The Psychiatric Institute, Center for Alcohol Research in Epigenetics, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, United States.
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13
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Schröder C, Leitão E, Wallner S, Schmitz G, Klein-Hitpass L, Sinha A, Jöckel KH, Heilmann-Heimbach S, Hoffmann P, Nöthen MM, Steffens M, Ebert P, Rahmann S, Horsthemke B. Regions of common inter-individual DNA methylation differences in human monocytes: genetic basis and potential function. Epigenetics Chromatin 2017; 10:37. [PMID: 28747224 PMCID: PMC5530492 DOI: 10.1186/s13072-017-0144-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 07/20/2017] [Indexed: 01/23/2023] Open
Abstract
Background There is increasing evidence for inter-individual methylation differences at CpG dinucleotides in the human genome, but the regional extent and function of these differences have not yet been studied in detail. For identifying regions of common methylation differences, we used whole genome bisulfite sequencing data of monocytes from five donors and a novel bioinformatic strategy. Results We identified 157 differentially methylated regions (DMRs) with four or more CpGs, almost none of which has been described before. The DMRs fall into different chromatin states, where methylation is inversely correlated with active, but not repressive histone marks. However, methylation is not correlated with the expression of associated genes. High-resolution single nucleotide polymorphism (SNP) genotyping of the five donors revealed evidence for a role of cis-acting genetic variation in establishing methylation patterns. To validate this finding in a larger cohort, we performed genome-wide association studies (GWAS) using SNP genotypes and 450k array methylation data from blood samples of 1128 individuals. Only 30/157 (19%) DMRs include at least one 450k CpG, which shows that these arrays miss a large proportion of DNA methylation variation. In most cases, the GWAS peak overlapped the CpG position, and these regions are enriched for CREB group, NF-1, Sp100 and CTCF binding motifs. In two cases, there was tentative evidence for a trans-effect by KRAB zinc finger proteins. Conclusions Allele-specific DNA methylation occurs in discrete chromosomal regions and is driven by genetic variation in cis and trans, but in general has little effect on gene expression. Electronic supplementary material The online version of this article (doi:10.1186/s13072-017-0144-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christopher Schröder
- Genome Informatics, Institute of Human Genetics, University of Duisburg-Essen, University Hospital Essen, Essen, Germany
| | - Elsa Leitão
- Institute of Human Genetics, University of Duisburg-Essen, University Hospital Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Stefan Wallner
- Institute for Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, Regensburg, Germany
| | - Gerd Schmitz
- Institute for Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, Regensburg, Germany
| | | | - Anupam Sinha
- Institute of Clinical Molecular Biology, Kiel University, University Hospital, Kiel, Germany
| | - Karl-Heinz Jöckel
- Institute of Medical Informatics, Biometry and Epidemiology, University Hospital Essen, Essen, Germany
| | - Stefanie Heilmann-Heimbach
- Institute of Human Genetics, School of Medicine, University Hospital of Bonn, University of Bonn, Bonn, Germany.,Department of Genomics, Life and Brain Center, University of Bonn, Bonn, Germany
| | - Per Hoffmann
- Institute of Human Genetics, School of Medicine, University Hospital of Bonn, University of Bonn, Bonn, Germany.,Department of Genomics, Life and Brain Center, University of Bonn, Bonn, Germany.,Institute of Medical Genetics and Pathology, University Hospital Basel, Basel, Switzerland.,Human Genomics Research Group, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Markus M Nöthen
- Institute of Human Genetics, School of Medicine, University Hospital of Bonn, University of Bonn, Bonn, Germany.,Department of Genomics, Life and Brain Center, University of Bonn, Bonn, Germany
| | - Michael Steffens
- Research Division, Federal Institute for Drugs and Medical Devices (BfArM), Bonn, Germany
| | - Peter Ebert
- Max Planck Institute for Informatics, Saarland Informatics Campus, Saarbrücken, Germany.,Saarbrücken Graduate School of Computer Science, Saarland Informatics Campus, Saarbrücken, Germany
| | - Sven Rahmann
- Genome Informatics, Institute of Human Genetics, University of Duisburg-Essen, University Hospital Essen, Essen, Germany
| | - Bernhard Horsthemke
- Institute of Human Genetics, University of Duisburg-Essen, University Hospital Essen, Hufelandstraße 55, 45147, Essen, Germany.
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14
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Variability of DNA Methylation within Schizophrenia Risk Loci across Subregions of Human Hippocampus. Genes (Basel) 2017; 8:genes8050143. [PMID: 28505127 PMCID: PMC5448017 DOI: 10.3390/genes8050143] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 05/09/2017] [Accepted: 05/11/2017] [Indexed: 12/22/2022] Open
Abstract
Identification of 108 genomic regions significantly associated with schizophrenia risk by the Psychiatric Genomics Consortium was a milestone for the field, and much work is now focused on determining the mechanism of risk associated with each locus. Within these regions, we investigated variability of DNA methylation, a low-level cellular phenotype closely linked to genotype, in two highly similar cellular populations sampled from the human hippocampus, to draw inferences about the elaboration of genotype to phenotype within these loci enriched for schizophrenia risk. DNA methylation was assessed with the Illumina HumanMethylation450 BeadArray in tissue laser-microdissected from the stratum oriens of subfield CA1 or CA2/3, regions having unique connectivity with intrinsic and extrinsic fiber systems within the hippocampus. Samples consisted of postmortem human hippocampus tissue from eight schizophrenia patients, eight bipolar disorder patients, and eight healthy control subjects. Within these genomic regions, we observed far greater difference in methylation patterns between circuit locations within subjects than in a single subregion between subjects across diagnostic groups, demonstrating the complexity of genotype to phenotype elaboration across the diverse circuitry of the human brain.
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15
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Mahfouz A, Huisman SMH, Lelieveldt BPF, Reinders MJT. Brain transcriptome atlases: a computational perspective. Brain Struct Funct 2017; 222:1557-1580. [PMID: 27909802 PMCID: PMC5406417 DOI: 10.1007/s00429-016-1338-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 11/15/2016] [Indexed: 01/31/2023]
Abstract
The immense complexity of the mammalian brain is largely reflected in the underlying molecular signatures of its billions of cells. Brain transcriptome atlases provide valuable insights into gene expression patterns across different brain areas throughout the course of development. Such atlases allow researchers to probe the molecular mechanisms which define neuronal identities, neuroanatomy, and patterns of connectivity. Despite the immense effort put into generating such atlases, to answer fundamental questions in neuroscience, an even greater effort is needed to develop methods to probe the resulting high-dimensional multivariate data. We provide a comprehensive overview of the various computational methods used to analyze brain transcriptome atlases.
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Affiliation(s)
- Ahmed Mahfouz
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
- Delft Bioinformatics Laboratory, Delft University of Technology, Delft, The Netherlands.
| | - Sjoerd M H Huisman
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
- Delft Bioinformatics Laboratory, Delft University of Technology, Delft, The Netherlands
| | - Boudewijn P F Lelieveldt
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
- Delft Bioinformatics Laboratory, Delft University of Technology, Delft, The Netherlands
| | - Marcel J T Reinders
- Delft Bioinformatics Laboratory, Delft University of Technology, Delft, The Netherlands
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16
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Jagannath V, Marinova Z, Monoranu CM, Walitza S, Grünblatt E. Expression of D-Amino Acid Oxidase ( DAO/ DAAO) and D-Amino Acid Oxidase Activator ( DAOA/G72) during Development and Aging in the Human Post-mortem Brain. Front Neuroanat 2017; 11:31. [PMID: 28428746 PMCID: PMC5382383 DOI: 10.3389/fnana.2017.00031] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 03/24/2017] [Indexed: 12/30/2022] Open
Abstract
In the brain, D-amino acid oxidase (DAO/DAAO) mainly oxidizes D-serine, a co-agonist of the N-methyl-D-aspartate (NMDA) receptors. Thus, DAO can regulate the function of NMDA receptors via D-serine breakdown. Furthermore, DAO activator (DAOA)/G72 has been reported as both DAOA and repressor. The co-expression of DAO and DAOA genes and proteins in the human brain is not yet elucidated. The aim of this study was to understand the regional and age span distribution of DAO and DAOA (mRNA and protein) in a concomitant manner. We determined DAO and DAOA mRNA and protein expression across six brain regions in normal human post-mortem brain samples (16 weeks of gestation to 91 years) using quantitative real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. We found higher expression of DAO mRNA in the cerebellum, whereas lower expression of DAO protein in the cerebellum compared to the other brain regions studied, which suggests post-transcriptional regulation. We detected DAOA protein but not DAOA mRNA in all brain regions studied, suggesting a tightly regulated expression. To understand this regulation at the transcriptional level, we analyzed DNA methylation levels at DAO and DAOA CpG sites in the cerebellum and frontal cortex of control human post-mortem brain obtained from Gene Expression Omnibus datasets. Indeed, DAO and DAOA CpG sites in the cerebellum were significantly more methylated than those in the frontal cortex. While investigating lifespan effects, we found that DAO mRNA levels were positively correlated with age <2 years in the cerebellum and amygdala. We also detected a significant positive correlation (controlled for age) between DAO and DAOA protein in all of the brain regions studied except for the frontal cortex. In summary, DAO and DAOA expression in the human brain are both age and brain region dependent.
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Affiliation(s)
- Vinita Jagannath
- Molecular and Neurobiochemistry Laboratory, Centre for Child and Adolescent Psychiatry Research, Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of ZurichZurich, Switzerland
| | - Zoya Marinova
- Molecular and Neurobiochemistry Laboratory, Centre for Child and Adolescent Psychiatry Research, Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of ZurichZurich, Switzerland
| | - Camelia-Maria Monoranu
- Department of Neuropathology, Institute of Pathology, University of WürzburgWürzburg, Germany
| | - Susanne Walitza
- Molecular and Neurobiochemistry Laboratory, Centre for Child and Adolescent Psychiatry Research, Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of ZurichZurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH ZurichZurich, Switzerland.,Zurich Center for Integrative Human Physiology, University of ZurichZurich, Switzerland
| | - Edna Grünblatt
- Molecular and Neurobiochemistry Laboratory, Centre for Child and Adolescent Psychiatry Research, Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of ZurichZurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH ZurichZurich, Switzerland.,Zurich Center for Integrative Human Physiology, University of ZurichZurich, Switzerland
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17
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Goodman JI. Incorporation of an Epigenetic Evaluation into Safety Assessment: What we First Need to Know. CURRENT OPINION IN TOXICOLOGY 2017; 3:20-24. [PMID: 30740577 DOI: 10.1016/j.cotox.2017.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The rapidly evolving field of epigenetic regulation of gene expression is having an impact across the spectrum of biomedical research. Toxicologists have embraced this area as evidenced by their increasing focus on discerning potential epigenetic mechanisms underlying mechanisms by which chemical and physical agents might cause toxicity. It is not surprising that an interest in epigenetic mechanisms of toxicity would lead to a desire to incorporate an epigenetic component into safety assessment. However, premature movement in this direction carries the risk of imposing more confusion than light. This commentary provides an overview of epigenetics, with an emphasis on how the various epigenetic parameters are integrated, as a basis for understanding the complexity behind the desire to include epigenetic evaluations in safety evaluations. Basically, we have much more to learn before turning the goal into a reality. However, considerable progress has been made with regard to using epigenetic profiles as signatures of xenobiotic exposure.
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Affiliation(s)
- Jay I Goodman
- Michigan State University Department of Pharmacology and Toxicology East Lansing, Michigan 48824 USA
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18
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Banlaki Z, Cimarelli G, Viranyi Z, Kubinyi E, Sasvari-Szekely M, Ronai Z. DNA methylation patterns of behavior-related gene promoter regions dissect the gray wolf from domestic dog breeds. Mol Genet Genomics 2017; 292:685-697. [DOI: 10.1007/s00438-017-1305-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 03/02/2017] [Indexed: 12/26/2022]
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19
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Gagliano SA. It's All in the Brain: A Review of Available Functional Genomic Annotations. Biol Psychiatry 2017; 81:478-483. [PMID: 27788914 DOI: 10.1016/j.biopsych.2016.08.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 08/02/2016] [Accepted: 08/04/2016] [Indexed: 10/21/2022]
Abstract
What makes the molecular study of psychiatric and other neurological conditions particularly challenging compared with other complex traits is the difficulty of accessing the relevant tissue. The Encyclopedia of DNA Elements (ENCODE) project was one of the earliest producers of brain-derived epigenetic functional genomic data, albeit initially from only two cancerous brain cell lines for a limited number of epigenetic marks. It has only been in very recent years that such data from human brain tissue have been made available from various sources. Yet, these data are scattered throughout the literature with no central organization. This review summarizes the availability and accessibility of brain epigenetic and functional genomic data as a single resource to allow investigators to easily access available brain annotations and thus incorporate this wealth of information into their research to make important advances in the field of neuroscience.
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Affiliation(s)
- Sarah A Gagliano
- Centre for Addiction and Mental Health, Campbell Family Mental Health Research Institute, Toronto, Canada; Department of Medical & Molecular Genetics, Guy's Hospital, King's College London, London, United Kingdom.
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20
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Hartwig FP, Loret de Mola C, Davies NM, Victora CG, Relton CL. Breastfeeding effects on DNA methylation in the offspring: A systematic literature review. PLoS One 2017; 12:e0173070. [PMID: 28257446 PMCID: PMC5336253 DOI: 10.1371/journal.pone.0173070] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 02/14/2017] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Breastfeeding benefits both infants and mothers. Recent research shows long-term health and human capital benefits among individuals who were breastfed. Epigenetic mechanisms have been suggested as potential mediators of the effects of early-life exposures on later health outcomes. We reviewed the literature on the potential effects of breastfeeding on DNA methylation. METHODS Studies reporting original results and evaluating DNA methylation differences according to breastfeeding/breast milk groups (e.g., ever vs. never comparisons, different categories of breastfeeding duration, etc) were eligible. Six databases were searched simultaneously using Ovid, and the resulting studies were evaluated independently by two reviewers. RESULTS Seven eligible studies were identified. Five were conducted in humans. Studies were heterogeneous regarding sample selection, age, target methylation regions, methylation measurement and breastfeeding categorisation. Collectively, the studies suggest that breastfeeding might be negatively associated with promoter methylation of LEP (which encodes an anorexigenic hormone), CDKN2A (involved in tumour suppression) and Slc2a4 genes (which encodes an insulin-related glucose transporter) and positively with promoter methylation of the Nyp (which encodes an orexigenic neuropeptide) gene, as well as influence global methylation patterns and modulate epigenetic effects of some genetic variants. CONCLUSIONS The findings from our systematic review are far from conclusive due to the small number of studies and their inherent limitations. Further studies are required to understand the actual potential role of epigenetics in the associations of breastfeeding with later health outcomes. Suggestions for future investigations, focusing on epigenome-wide association studies, are provided.
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Affiliation(s)
- Fernando Pires Hartwig
- Postgraduate Programme in Epidemiology, Federal University of Pelotas, Pelotas, Brazil
- MRC Integrative Epidemiology Unit, School of Social & Community Medicine, University of Bristol, Bristol, United Kingdom
- * E-mail:
| | | | - Neil Martin Davies
- MRC Integrative Epidemiology Unit, School of Social & Community Medicine, University of Bristol, Bristol, United Kingdom
- School of Social and Community Medicine, University of Bristol, United Kingdom
| | - Cesar Gomes Victora
- Postgraduate Programme in Epidemiology, Federal University of Pelotas, Pelotas, Brazil
| | - Caroline L. Relton
- MRC Integrative Epidemiology Unit, School of Social & Community Medicine, University of Bristol, Bristol, United Kingdom
- School of Social and Community Medicine, University of Bristol, United Kingdom
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21
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Abstract
5-methylcytosine and the oxidation product 5-hydroxymethylcytosine are two prominent epigenetic variants of the cytosine base in nuclear DNA of mammalian brains. We measured levels of 5-methylcytosine and 5-hydroxymethylcytosine by enzyme-linked immunosorbent assay in DNA from post-mortem cerebella of individuals with Parkinson’s disease and age-matched controls. 5-methylcytosine levels showed no significant differences between Parkinson’s disease and control DNA sample sets. In contrast, median 5-hydroxymethylcytosine levels were almost twice as high (p < 0.001) in both male and female Parkinson’s disease individuals compared with controls. The distinct epigenetic profile identified in cerebellar DNA of Parkinson’s disease patients raises the question whether elevated 5-hydroxymethylcytosine levels are a driver or a consequence of Parkinson’s disease.
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22
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Ponnaluri VKC, Ehrlich KC, Zhang G, Lacey M, Johnston D, Pradhan S, Ehrlich M. Association of 5-hydroxymethylation and 5-methylation of DNA cytosine with tissue-specific gene expression. Epigenetics 2017; 12:123-138. [PMID: 27911668 PMCID: PMC5330441 DOI: 10.1080/15592294.2016.1265713] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 11/10/2016] [Accepted: 11/21/2016] [Indexed: 12/15/2022] Open
Abstract
Differentially methylated or hydroxymethylated regions (DMRs) in mammalian DNA are often associated with tissue-specific gene expression but the functional relationships are still being unraveled. To elucidate these relationships, we studied 16 human genes containing myogenic DMRs by analyzing profiles of their epigenetics and transcription and quantitatively assaying 5-hydroxymethylcytosine (5hmC) and 5-methylcytosine (5mC) at specific sites in these genes in skeletal muscle (SkM), myoblasts, heart, brain, and diverse other samples. Although most human promoters have little or no methylation regardless of expression, more than half of the genes that we chose to study-owing to their myogenic DMRs-overlapped tissue-specific alternative or cryptic promoters displaying corresponding tissue-specific differences in histone modifications. The 5mC levels in myoblast DMRs were significantly associated with 5hmC levels in SkM at the same site. Hypermethylated myogenic DMRs within CDH15, a muscle- and cerebellum-specific cell adhesion gene, and PITX3, a homeobox gene, were used for transfection in reporter gene constructs. These intragenic DMRs had bidirectional tissue-specific promoter activity that was silenced by in vivo-like methylation. The CDH15 DMR, which was previously associated with an imprinted maternal germline DMR in mice, had especially strong promoter activity in myogenic host cells. These findings are consistent with the controversial hypothesis that intragenic DNA methylation can facilitate transcription and is not just a passive consequence of it. Our results support varied roles for tissue-specific 5mC- or 5hmC-enrichment in suppressing inappropriate gene expression from cryptic or alternative promoters and in increasing the plasticity of gene expression required for development and rapid responses to tissue stress or damage.
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Affiliation(s)
| | - Kenneth C. Ehrlich
- Center for Bioinformatics and Genomics, Tulane University Health Sciences Center, New Orleans, LA, USA
| | | | - Michelle Lacey
- Department of Mathematics, Tulane Health Sciences Center and Tulane University, New Orleans, LA, USA
| | - Douglas Johnston
- Department of Microbiology, Immunology and Parasitology, LSU Health Sciences Center, New Orleans, LA, USA
| | | | - Melanie Ehrlich
- Center for Bioinformatics and Genomics, Tulane University Health Sciences Center, New Orleans, LA, USA
- Hayward Genetics Center and Tulane Cancer Center, Tulane University Health Sciences Center, New Orleans, LA, USA
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23
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Ellison EM, Abner EL, Lovell MA. Multiregional analysis of global 5-methylcytosine and 5-hydroxymethylcytosine throughout the progression of Alzheimer's disease. J Neurochem 2017; 140:383-394. [PMID: 27889911 PMCID: PMC5250541 DOI: 10.1111/jnc.13912] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 11/19/2016] [Accepted: 11/22/2016] [Indexed: 12/16/2022]
Abstract
Epigenetic modifications to cytosine are known to alter transcriptional states and deregulate gene expression in cancer, embryonic development, and most recently in neurodegeneration. To test the hypothesis that global levels of cytosine modification are altered throughout the progression of Alzheimer's disease, 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) were quantified using gas chromatography/mass spectrometry (GC/MS) and stable labeled internal standards of cytosine, 5-mC, and 5-hmC. Cytosine modifications were quantified in DNA extracted from tissue specimens of four brain regions (cerebellum, inferior parietal lobe, superior and middle temporal gyrus, and hippocampus/parahippocampal gyrus) of cognitively normal control (NC) subjects and subjects with mild cognitive impairment (MCI), preclinical Alzheimer's disease (PCAD), late onset Alzheimer's disease, frontotemporal lobar degeneration (FTLD) and dementia with Lewy bodies (DLB). Repeated measures analyses of the data show significant alterations in 5-mC and 5-hmC in early stages of Alzheimer's disease (PCAD and MCI), as well as FTLD and DLB subjects, across multiple regions of the brain. These data suggest alterations in epigenetic regulation of genes may play an early role in the progression of AD as well as other types of neurodegeneration.
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Affiliation(s)
| | - Erin L. Abner
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY
- Department of Epidemiology, University of Kentucky, Lexington, KY
| | - Mark A. Lovell
- Department of Chemistry, University of Kentucky, Lexington, KY
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY
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24
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Hannon E, Lunnon K, Schalkwyk L, Mill J. Interindividual methylomic variation across blood, cortex, and cerebellum: implications for epigenetic studies of neurological and neuropsychiatric phenotypes. Epigenetics 2016; 10:1024-32. [PMID: 26457534 PMCID: PMC4844197 DOI: 10.1080/15592294.2015.1100786] [Citation(s) in RCA: 310] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Given the tissue-specific nature of epigenetic processes, the assessment of disease-relevant tissue is an important consideration for epigenome-wide association studies (EWAS). Little is known about whether easily accessible tissues, such as whole blood, can be used to address questions about interindividual epigenomic variation in inaccessible tissues, such as the brain. We quantified DNA methylation in matched DNA samples isolated from whole blood and 4 brain regions (prefrontal cortex, entorhinal cortex, superior temporal gyrus, and cerebellum) from 122 individuals. We explored co-variation between tissues and the extent to which methylomic variation in blood is predictive of interindividual variation identified in the brain. For the majority of DNA methylation sites, interindividual variation in whole blood is not a strong predictor of interindividual variation in the brain, although the relationship with cortical regions is stronger than with the cerebellum. Variation at a subset of probes is strongly correlated across tissues, even in instances when the actual level of DNA methylation is significantly different between them. A substantial proportion of this co-variation, however, is likely to result from genetic influences. Our data suggest that for the majority of the genome, a blood-based EWAS for disorders where brain is presumed to be the primary tissue of interest will give limited information relating to underlying pathological processes. These results do not, however, discount the utility of using a blood-based EWAS to identify biomarkers of disease phenotypes manifest in the brain. We have generated a searchable database for the interpretation of data from blood-based EWAS analyses (http://epigenetics.essex.ac.uk/bloodbrain/).
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Affiliation(s)
- Eilis Hannon
- a University of Exeter Medical School; University of Exeter ; Devon , UK
| | - Katie Lunnon
- a University of Exeter Medical School; University of Exeter ; Devon , UK
| | - Leonard Schalkwyk
- b School of Biological Sciences; University of Essex ; Wivenhoe Park, Colchester , UK
| | - Jonathan Mill
- a University of Exeter Medical School; University of Exeter ; Devon , UK.,c Institute of Psychiatry; Psychology & Neuroscience; King's College London ; De Crespigny Park, London , UK
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25
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Greenhouse I, Noah S, Maddock RJ, Ivry RB. Individual differences in GABA content are reliable but are not uniform across the human cortex. Neuroimage 2016; 139:1-7. [PMID: 27288552 DOI: 10.1016/j.neuroimage.2016.06.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 05/01/2016] [Accepted: 06/06/2016] [Indexed: 11/15/2022] Open
Abstract
1H magnetic resonance spectroscopy (MRS) provides a powerful tool to measure gamma-aminobutyric acid (GABA), the principle inhibitory neurotransmitter in the human brain. We asked whether individual differences in MRS estimates of GABA are uniform across the cortex or vary between regions. In two sessions, resting GABA concentrations in the lateral prefrontal, sensorimotor, dorsal premotor, and occipital cortices were measured in twenty-eight healthy individuals. GABA estimates within each region were stable across weeks, with low coefficients of variation. Despite this stability, the GABA estimates were not correlated between regions. In contrast, the percentage of brain tissue per volume, a control measure, was correlated between the three anterior regions. These results provide an interesting dissociation between an anatomical measure of individual differences and a neurochemical measure. The different patterns of anatomy and GABA concentrations have implications for understanding regional variation in the molecular topography of the brain in health and disease.
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Affiliation(s)
- Ian Greenhouse
- University of California, Berkeley, Berkeley, CA, United States.
| | - Sean Noah
- University of California, Berkeley, Berkeley, CA, United States
| | | | - Richard B Ivry
- University of California, Berkeley, Berkeley, CA, United States
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26
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Chatterjee A, Lagisz M, Rodger EJ, Zhen L, Stockwell PA, Duncan EJ, Horsfield JA, Jeyakani J, Mathavan S, Ozaki Y, Nakagawa S. Sex differences in DNA methylation and expression in zebrafish brain: a test of an extended 'male sex drive' hypothesis. Gene 2016; 590:307-16. [PMID: 27259666 DOI: 10.1016/j.gene.2016.05.042] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/20/2016] [Accepted: 05/29/2016] [Indexed: 12/17/2022]
Abstract
The sex drive hypothesis predicts that stronger selection on male traits has resulted in masculinization of the genome. Here we test whether such masculinizing effects can be detected at the level of the transcriptome and methylome in the adult zebrafish brain. Although methylation is globally similar, we identified 914 specific differentially methylated CpGs (DMCs) between males and females (435 were hypermethylated and 479 were hypomethylated in males compared to females). These DMCs were prevalent in gene body, intergenic regions and CpG island shores. We also discovered 15 distinct CpG clusters with striking sex-specific DNA methylation differences. In contrast, at transcriptome level, more female-biased genes than male-biased genes were expressed, giving little support for the male sex drive hypothesis. Our study provides genome-wide methylome and transcriptome assessment and sheds light on sex-specific epigenetic patterns and in zebrafish for the first time.
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Affiliation(s)
- Aniruddha Chatterjee
- Department of Pathology, Dunedin School of Medicine, University of Otago, 270 Great King Street, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Level 2, 3A Symonds Street, Auckland, New Zealand.
| | - Malgorzata Lagisz
- Department of Zoology, University of Otago, 340 Great King Street, Dunedin 9054, New Zealand; Evolution & Ecology Research Centre and School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, 2052 Sydney, NSW, Australia.
| | - Euan J Rodger
- Department of Pathology, Dunedin School of Medicine, University of Otago, 270 Great King Street, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Level 2, 3A Symonds Street, Auckland, New Zealand.
| | - Li Zhen
- LKC School of Medicine, Nanyang Technological University and Human Genetics Division, Genome Institute of Singapore, Singapore.
| | - Peter A Stockwell
- Department of Biochemistry, University of Otago, 710 Cumberland Street, Dunedin 9054, New Zealand.
| | - Elizabeth J Duncan
- Department of Biochemistry, University of Otago, 710 Cumberland Street, Dunedin 9054, New Zealand.
| | - Julia A Horsfield
- Department of Pathology, Dunedin School of Medicine, University of Otago, 270 Great King Street, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Level 2, 3A Symonds Street, Auckland, New Zealand.
| | - Justin Jeyakani
- LKC School of Medicine, Nanyang Technological University and Human Genetics Division, Genome Institute of Singapore, Singapore.
| | - Sinnakaruppan Mathavan
- LKC School of Medicine, Nanyang Technological University and Human Genetics Division, Genome Institute of Singapore, Singapore.
| | - Yuichi Ozaki
- Department of Biology, Keio University, 4-1-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8521, Japan.
| | - Shinichi Nakagawa
- Department of Zoology, University of Otago, 340 Great King Street, Dunedin 9054, New Zealand; Evolution & Ecology Research Centre and School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, 2052 Sydney, NSW, Australia; Diabetes and Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia.
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27
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Heylen L, Thienpont B, Naesens M, Lambrechts D, Sprangers B. The Emerging Role of DNA Methylation in Kidney Transplantation: A Perspective. Am J Transplant 2016; 16:1070-8. [PMID: 26780242 DOI: 10.1111/ajt.13585] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 09/28/2015] [Accepted: 10/14/2015] [Indexed: 01/25/2023]
Abstract
Allograft outcome depends on a range of factors, including donor age, the allo-immune response, ischemia-reperfusion injury, and interstitial fibrosis of the allograft. Changes in the epigenome, and in DNA methylation in particular, have been implicated in each of these processes, in either the kidney or other organ systems. This review provides a primer for DNA methylation analyses and a discussion of the strengths and weaknesses of current studies, but it is also a perspective for future DNA methylation research in kidney transplantation. We present exciting prospects for leveraging DNA methylation analyses as a tool in kidney biology research, and as a diagnostic or prognostic marker for predicting allograft quality and success. Topics discussed include DNA methylation changes in aging and in response to hypoxia and oxidative stress upon ischemia-reperfusion injury. Moreover, emerging evidence suggests that DNA methylation contributes to organ fibrosis and that systemic DNA methylation alterations correlate with the rate of kidney function decline in patients with chronic kidney disease and end-stage renal failure. Monitoring or targeting the epigenome could therefore reveal novel therapeutic approaches in transplantation and open up paths to biomarker discovery and targeted therapy.
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Affiliation(s)
- L Heylen
- Department of Nephrology and Renal Transplantation, University Hospitals Leuven, Leuven, Belgium.,Department of Immunology and Microbiology, KU Leuven, Leuven, Belgium.,Laboratory of Translational Genetics, Department of Oncology, KU Leuven, Leuven, Belgium.,Vesalius Research Center, VIB, Leuven, Belgium
| | - B Thienpont
- Laboratory of Translational Genetics, Department of Oncology, KU Leuven, Leuven, Belgium.,Vesalius Research Center, VIB, Leuven, Belgium
| | - M Naesens
- Department of Nephrology and Renal Transplantation, University Hospitals Leuven, Leuven, Belgium.,Department of Immunology and Microbiology, KU Leuven, Leuven, Belgium
| | - D Lambrechts
- Laboratory of Translational Genetics, Department of Oncology, KU Leuven, Leuven, Belgium.,Vesalius Research Center, VIB, Leuven, Belgium
| | - B Sprangers
- Department of Nephrology and Renal Transplantation, University Hospitals Leuven, Leuven, Belgium.,Department of Immunology and Microbiology, KU Leuven, Leuven, Belgium
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28
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Abstract
'Epigenome' refers to the panoply of chemical modifications borne by DNA and its associated proteins that locally affect genome function. Epigenomic patterns are thought to be determined by external constraints resulting from development, disease and the environment, but DNA sequence is also a potential influence. We propose that domains of relatively uniform DNA base composition may modulate the epigenome through cell type-specific proteins that recognize short, frequent sequence motifs. Differential recruitment of epigenomic modifiers may adjust gene expression in multigene blocks as an alternative to tuning the activity of each gene separately, thus simplifying gene expression programming.
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29
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Houtepen LC, van Bergen AH, Vinkers CH, Boks MPM. DNA methylation signatures of mood stabilizers and antipsychotics in bipolar disorder. Epigenomics 2016; 8:197-208. [DOI: 10.2217/epi.15.98] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Aim: In view of the potential effects of psychiatric drugs on DNA methylation, we investigated whether medication use in bipolar disorder is associated with DNA methylation signatures. Experimental procedures: Blood-based DNA methylation patterns of six frequently used psychotropic drugs (lithium, quetiapine, olanzapine, lamotrigine, carbamazepine, and valproic acid) were examined in 172 bipolar disorder patients. After adjustment for cell type composition, we investigated gene networks, principal components, hypothesis-driven genes and epigenome-wide individual loci. Results: Valproic acid and quetiapine were significantly associated with altered methylation signatures after adjustment for drug-related changes on celltype composition. Conclusion: Psychiatric drugs influence DNA methylation patterns over and above cell type composition in bipolar disorder. Drug-related changes in DNA methylation are therefore not only an important confounder in psychiatric epigenetics but may also inform on the biological mechanisms underlying drug efficacy.
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Affiliation(s)
- Lotte C Houtepen
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
| | - Annet H van Bergen
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
| | - Christiaan H Vinkers
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
| | - Marco PM Boks
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
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30
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Marzi SJ, Meaburn EL, Dempster EL, Lunnon K, Paya-Cano JL, Smith RG, Volta M, Troakes C, Schalkwyk LC, Mill J. Tissue-specific patterns of allelically-skewed DNA methylation. Epigenetics 2016; 11:24-35. [PMID: 26786711 PMCID: PMC4846124 DOI: 10.1080/15592294.2015.1127479] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
While DNA methylation is usually thought to be symmetrical across both alleles, there are some notable exceptions. Genomic imprinting and X chromosome inactivation are two well-studied sources of allele-specific methylation (ASM), but recent research has indicated a more complex pattern in which genotypic variation can be associated with allelically-skewed DNA methylation in cis. Given the known heterogeneity of DNA methylation across tissues and cell types we explored inter- and intra-individual variation in ASM across several regions of the human brain and whole blood from multiple individuals. Consistent with previous studies, we find widespread ASM with > 4% of the ∼220,000 loci interrogated showing evidence of allelically-skewed DNA methylation. We identify ASM flanking known imprinted regions, and show that ASM sites are enriched in DNase I hypersensitivity sites and often located in an extended genomic context of intermediate DNA methylation. We also detect examples of genotype-driven ASM, some of which are tissue-specific. These findings contribute to our understanding of the nature of differential DNA methylation across tissues and have important implications for genetic studies of complex disease. As a resource to the community, ASM patterns across each of the tissues studied are available in a searchable online database: http://epigenetics.essex.ac.uk/ASMBrainBlood.
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Affiliation(s)
- Sarah J Marzi
- a Institute of Psychiatry, Psychology and Neuroscience, King's College London , London , UK
| | - Emma L Meaburn
- b Department of Psychological Sciences , Birkbeck, University of London , London , UK
| | - Emma L Dempster
- c University of Exeter Medical School, University of Exeter , Exeter , UK
| | - Katie Lunnon
- c University of Exeter Medical School, University of Exeter , Exeter , UK
| | - Jose L Paya-Cano
- a Institute of Psychiatry, Psychology and Neuroscience, King's College London , London , UK
| | - Rebecca G Smith
- c University of Exeter Medical School, University of Exeter , Exeter , UK
| | - Manuela Volta
- a Institute of Psychiatry, Psychology and Neuroscience, King's College London , London , UK
| | - Claire Troakes
- a Institute of Psychiatry, Psychology and Neuroscience, King's College London , London , UK
| | | | - Jonathan Mill
- a Institute of Psychiatry, Psychology and Neuroscience, King's College London , London , UK.,c University of Exeter Medical School, University of Exeter , Exeter , UK
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31
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Genome-wide DNA methylation map of human neutrophils reveals widespread inter-individual epigenetic variation. Sci Rep 2015; 5:17328. [PMID: 26612583 PMCID: PMC4661471 DOI: 10.1038/srep17328] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 10/29/2015] [Indexed: 11/13/2022] Open
Abstract
The extent of variation in DNA methylation patterns in healthy individuals is not yet well documented. Identification of inter-individual epigenetic variation is important for understanding phenotypic variation and disease susceptibility. Using neutrophils from a cohort of healthy individuals, we generated base-resolution DNA methylation maps to document inter-individual epigenetic variation. We identified 12851 autosomal inter-individual variably methylated fragments (iVMFs). Gene promoters were the least variable, whereas gene body and upstream regions showed higher variation in DNA methylation. The iVMFs were relatively enriched in repetitive elements compared to non-iVMFs, and were associated with genome regulation and chromatin function elements. Further, variably methylated genes were disproportionately associated with regulation of transcription, responsive function and signal transduction pathways. Transcriptome analysis indicates that iVMF methylation at differentially expressed exons has a positive correlation and local effect on the inclusion of that exon in the mRNA transcript.
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32
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Grayson DR, Guidotti A. Merging data from genetic and epigenetic approaches to better understand autistic spectrum disorder. Epigenomics 2015; 8:85-104. [PMID: 26551091 PMCID: PMC4864049 DOI: 10.2217/epi.15.92] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that is characterized by a wide range of cognitive and behavioral abnormalities. Genetic research has identified large numbers of genes that contribute to ASD phenotypes. There is compelling evidence that environmental factors contribute to ASD through influences that differentially impact the brain through epigenetic mechanisms. Both genetic mutations and epigenetic influences alter gene expression in different cell types of the brain. Mutations impact the expression of large numbers of genes and also have downstream consequences depending on specific pathways associated with the mutation. Environmental factors impact the expression of sets of genes by altering methylation/hydroxymethylation patterns, local histone modification patterns and chromatin remodeling. Herein, we discuss recent developments in the research of ASD with a focus on epigenetic pathways as a complement to current genetic screening.
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Affiliation(s)
- Dennis R Grayson
- Department of Psychiatry, The Psychiatric Institute, University of Illinois at Chicago, 1601 W. Taylor St., Chicago, IL 60607, USA
| | - Alessandro Guidotti
- Department of Psychiatry, The Psychiatric Institute, University of Illinois at Chicago, 1601 W. Taylor St., Chicago, IL 60607, USA
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33
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Yang J, Yu L, Gaiteri C, Srivastava GP, Chibnik LB, Leurgans SE, Schneider JA, Meissner A, De Jager PL, Bennett DA. Association of DNA methylation in the brain with age in older persons is confounded by common neuropathologies. Int J Biochem Cell Biol 2015; 67:58-64. [PMID: 26003740 PMCID: PMC4564337 DOI: 10.1016/j.biocel.2015.05.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 05/10/2015] [Accepted: 05/11/2015] [Indexed: 11/18/2022]
Abstract
DNA methylation plays a crucial role in the regulation of gene expression, cell differentiation and development. Previous studies have reported age-related alterations of methylation levels in the human brain across the lifespan, but little is known about whether the observed association with age is confounded by common neuropathologies among older persons. Using genome-wide DNA methylation data from 740 postmortem brains, we interrogated 420,132 CpG sites across the genome in a cohort of individuals with ages from 66 to 108 years old, a range of ages at which many neuropathologic indices become quite common. We compared the association of DNA methylation prior to and following adjustment for common neuropathologies using a series of linear regression models. In the simplest model adjusting for technical factors including batch effect and bisulfite conversion rate, we found 8156 CpGs associated with age. The number of CpGs associated with age dropped by more than 10% following adjustment for sex. Notably, after adjusting for common neuropathologies, the total number of CpGs associated with age was reduced by approximately 40%, compared to the sex-adjusted model. These data illustrate that the association of methylation changes in the brain with age is inflated if one does not account for age-related brain pathologies. This article is part of a Directed Issue entitled: Epigenetics dynamics in development and disease.
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Affiliation(s)
- Jingyun Yang
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA.
| | - Lei Yu
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Christopher Gaiteri
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Gyan P Srivastava
- Program in Translational NeuroPsychiatric Genomics, Departments of Neurology & Psychiatry, Institute for the Neurosciences, Brigham and Women's Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
| | - Lori B Chibnik
- Program in Translational NeuroPsychiatric Genomics, Departments of Neurology & Psychiatry, Institute for the Neurosciences, Brigham and Women's Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
| | - Sue E Leurgans
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Julie A Schneider
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA; Department of Pathology, Rush University Medical Center, Chicago, IL, USA
| | - Alexander Meissner
- Broad Institute of MIT and Harvard, Cambridge, MA, USA; Harvard Stem Cell Institute, Cambridge, MA, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA
| | - Philip L De Jager
- Program in Translational NeuroPsychiatric Genomics, Departments of Neurology & Psychiatry, Institute for the Neurosciences, Brigham and Women's Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
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