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Abstract
Biomarker discovery and validation are necessary for improving the prediction of clinical outcomes and patient monitoring. Despite considerable interest in biomarker discovery and development, improvements in the range and quality of biomarkers are still needed. The main challenge is how to integrate preclinical data to obtain a reliable biomarker that can be measured with acceptable costs in routine clinical practice. Epigenetic alterations are already being incorporated as valuable candidates in the biomarker field. Furthermore, their reversible nature offers a promising opportunity to ameliorate disease symptoms by using epigenetic-based therapy. Thus, beyond helping to understand disease biology, clinical epigenetics is being incorporated into patient management in oncology, as well as being explored for clinical applicability for other human pathologies such as neurological and infectious diseases and immune system disorders.
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Gunasekara CJ, Scott CA, Laritsky E, Baker MS, MacKay H, Duryea JD, Kessler NJ, Hellenthal G, Wood AC, Hodges KR, Gandhi M, Hair AB, Silver MJ, Moore SE, Prentice AM, Li Y, Chen R, Coarfa C, Waterland RA. A genomic atlas of systemic interindividual epigenetic variation in humans. Genome Biol 2019; 20:105. [PMID: 31155008 PMCID: PMC6545702 DOI: 10.1186/s13059-019-1708-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 05/06/2019] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND DNA methylation is thought to be an important determinant of human phenotypic variation, but its inherent cell type specificity has impeded progress on this question. At exceptional genomic regions, interindividual variation in DNA methylation occurs systemically. Like genetic variants, systemic interindividual epigenetic variants are stable, can influence phenotype, and can be assessed in any easily biopsiable DNA sample. We describe an unbiased screen for human genomic regions at which interindividual variation in DNA methylation is not tissue-specific. RESULTS For each of 10 donors from the NIH Genotype-Tissue Expression (GTEx) program, CpG methylation is measured by deep whole-genome bisulfite sequencing of genomic DNA from tissues representing the three germ layer lineages: thyroid (endoderm), heart (mesoderm), and brain (ectoderm). We develop a computational algorithm to identify genomic regions at which interindividual variation in DNA methylation is consistent across all three lineages. This approach identifies 9926 correlated regions of systemic interindividual variation (CoRSIVs). These regions, comprising just 0.1% of the human genome, are inter-correlated over long genomic distances, associated with transposable elements and subtelomeric regions, conserved across diverse human ethnic groups, sensitive to periconceptional environment, and associated with genes implicated in a broad range of human disorders and phenotypes. CoRSIV methylation in one tissue can predict expression of associated genes in other tissues. CONCLUSIONS In addition to charting a previously unexplored molecular level of human individuality, this atlas of human CoRSIVs provides a resource for future population-based investigations into how interindividual epigenetic variation modulates risk of disease.
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Affiliation(s)
- Chathura J Gunasekara
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - C Anthony Scott
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Eleonora Laritsky
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Maria S Baker
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Harry MacKay
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Jack D Duryea
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Noah J Kessler
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Keneba, The Gambia
- Department of Women and Children's Health, King's College London, London, UK
| | - Garrett Hellenthal
- Department of Genetics, Evolution and Environment, UCL Genetics Institute, University College London, London, WC1E 6BT, UK
| | - Alexis C Wood
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Kelly R Hodges
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX, USA
| | - Manisha Gandhi
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX, USA
| | - Amy B Hair
- Department of Pediatrics - Neonatology, Baylor College of Medicine, Houston, TX, USA
| | - Matt J Silver
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Keneba, The Gambia
| | - Sophie E Moore
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Keneba, The Gambia
- Department of Women and Children's Health, King's College London, London, UK
| | - Andrew M Prentice
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Keneba, The Gambia
| | - Yumei Li
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Rui Chen
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Cristian Coarfa
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
| | - Robert A Waterland
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
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53
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Mohandas N, Loke YJ, Hopkins S, Mackenzie L, Bennett C, Berkovic SF, Vadlamudi L, Craig JM. Evidence for type-specific DNA methylation patterns in epilepsy: a discordant monozygotic twin approach. Epigenomics 2019; 11:951-968. [DOI: 10.2217/epi-2018-0136] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Aim: Epilepsy is a common neurological disorder characterized by recurrent seizures. We performed epigenetic analyses between and within 15 monozygotic (MZ) twin pairs discordant for focal or generalized epilepsy. Methods: DNA methylation analysis was performed using Illumina Infinium MethylationEPIC arrays, in blood and buccal samples. Results: Differentially methylated regions between epilepsy types associated with PM20D1 and GFPT2 genes in both tissues. Within MZ discordant twin pairs, differentially methylated regions associated with OTX1 and ARID5B genes for generalized epilepsy and TTC39C and DLX5 genes for focal epilepsy. Conclusion: This is the first epigenome-wide association study, utilizing the discordant MZ co-twin model, to deepen our understanding of the neurobiology of epilepsy.
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Affiliation(s)
- Namitha Mohandas
- Environmental & Genetic Epidemiology Research, Murdoch Children's Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Flemington Road, Parkville, Victoria, Australia
| | - Yuk Jing Loke
- Environmental & Genetic Epidemiology Research, Murdoch Children's Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Victoria, Australia
| | - Stephanie Hopkins
- Environmental & Genetic Epidemiology Research, Murdoch Children's Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Victoria, Australia
- School of Medicine & Public Health, University of Newcastle, Newcastle, New South Wales, Australia
| | - Lisa Mackenzie
- Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Queensland, Australia
| | - Carmen Bennett
- Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Queensland, Australia
| | - Samuel F Berkovic
- Epilepsy Research Centre, University of Melbourne, Austin Health, Victoria, Australia
| | - Lata Vadlamudi
- Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Queensland, Australia
- Royal Brisbane & Women's Hospital, Queensland, Australia
| | - Jeffrey M Craig
- Environmental & Genetic Epidemiology Research, Murdoch Children's Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Flemington Road, Parkville, Victoria, Australia
- Centre for Molecular & Medical Research, School of Medicine, Deakin University, Geelong, Victoria 3220, Australia
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Semick SA, Bharadwaj RA, Collado-Torres L, Tao R, Shin JH, Deep-Soboslay A, Weiss JR, Weinberger DR, Hyde TM, Kleinman JE, Jaffe AE, Mattay VS. Integrated DNA methylation and gene expression profiling across multiple brain regions implicate novel genes in Alzheimer's disease. Acta Neuropathol 2019; 137:557-569. [PMID: 30712078 DOI: 10.1007/s00401-019-01966-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/09/2019] [Accepted: 01/22/2019] [Indexed: 12/14/2022]
Abstract
Late-onset Alzheimer's disease (AD) is a complex age-related neurodegenerative disorder that likely involves epigenetic factors. To better understand the epigenetic state associated with AD, we surveyed 420,852 DNA methylation (DNAm) sites from neurotypical controls (N = 49) and late-onset AD patients (N = 24) across four brain regions (hippocampus, entorhinal cortex, dorsolateral prefrontal cortex and cerebellum). We identified 858 sites with robust differential methylation collectively annotated to 772 possible genes (FDR < 5%, within 10 kb). These sites were overrepresented in AD genetic risk loci (p = 0.00655) and were enriched for changes during normal aging (p < 2.2 × 10-16), and nearby genes were enriched for processes related to cell-adhesion, immunity, and calcium homeostasis (FDR < 5%). To functionally validate these associations, we generated and analyzed corresponding transcriptome data to prioritize 130 genes within 10 kb of the differentially methylated sites. These 130 genes were differentially expressed between AD cases and controls and their expression was associated with nearby DNAm (p < 0.05). This integrated analysis implicates novel genes in Alzheimer's disease, such as ANKRD30B. These results highlight DNAm differences in Alzheimer's disease that have gene expression correlates, further implicating DNAm as an epigenetic mechanism underlying pathological molecular changes associated with AD. Furthermore, our framework illustrates the value of integrating epigenetic and transcriptomic data for understanding complex disease.
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Carullo NVN, Day JJ. Genomic Enhancers in Brain Health and Disease. Genes (Basel) 2019; 10:E43. [PMID: 30646598 PMCID: PMC6357130 DOI: 10.3390/genes10010043] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/08/2019] [Accepted: 01/08/2019] [Indexed: 01/18/2023] Open
Abstract
Enhancers are non-coding DNA elements that function in cis to regulate transcription from nearby genes. Through direct interactions with gene promoters, enhancers give rise to spatially and temporally precise gene expression profiles in distinct cell or tissue types. In the brain, the accurate regulation of these intricate expression programs across different neuronal classes gives rise to an incredible cellular and functional diversity. Newly developed technologies have recently allowed more accurate enhancer mapping and more sophisticated enhancer manipulation, producing rapid progress in our understanding of enhancer biology. Furthermore, identification of disease-linked genetic variation in enhancer regions has highlighted the potential influence of enhancers in brain health and disease. This review outlines the key role of enhancers as transcriptional regulators, reviews the current understanding of enhancer regulation in neuronal development, function and dysfunction and provides our thoughts on how enhancers can be targeted for technological and therapeutic goals.
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Affiliation(s)
- Nancy V N Carullo
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Jeremy J Day
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Abstract
Bioactive lipids control a wide variety of physiologic processes. We have recently identified a branch of bioactive lipid signaling mediated by N-acyl amino acids (NAAs) and the circulating enzyme peptidase M20 domain-containing 1 (PM20D1). Here we generate and characterize mice globally deficient in PM20D1. These PM20D1-KO mice have bidirectional changes in NAA levels in blood and tissues and exhibit a variety of metabolic and nociceptive phenotypes. Our findings elucidate the endogenous physiologic functions for NAA signaling in vivo and suggest PM20D1 inhibitors might be useful for the treatment of pain. N-acyl amino acids (NAAs) are a structurally diverse class of bioactive signaling lipids whose endogenous functions have largely remained uncharacterized. To clarify the physiologic roles of NAAs, we generated mice deficient in the circulating enzyme peptidase M20 domain-containing 1 (PM20D1). Global PM20D1-KO mice have dramatically reduced NAA hydrolase/synthase activities in tissues and blood with concomitant bidirectional dysregulation of endogenous NAAs. Compared with control animals, PM20D1-KO mice exhibit a variety of metabolic and pain phenotypes, including insulin resistance, altered body temperature in cold, and antinociceptive behaviors. Guided by these phenotypes, we identify N-oleoyl-glutamine (C18:1-Gln) as a key PM20D1-regulated NAA. In addition to its mitochondrial uncoupling bioactivity, C18:1-Gln also antagonizes certain members of the transient receptor potential (TRP) calcium channels including TRPV1. Direct administration of C18:1-Gln to mice is sufficient to recapitulate a subset of phenotypes observed in PM20D1-KO animals. These data demonstrate that PM20D1 is a dominant enzymatic regulator of NAA levels in vivo and elucidate physiologic functions for NAA signaling in metabolism and nociception.
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Volloch V, Rits S. Results of Beta Secretase-Inhibitor Clinical Trials Support Amyloid Precursor Protein-Independent Generation of Beta Amyloid in Sporadic Alzheimer's Disease. Med Sci (Basel) 2018; 6:medsci6020045. [PMID: 29865246 PMCID: PMC6024788 DOI: 10.3390/medsci6020045] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 05/20/2018] [Accepted: 05/29/2018] [Indexed: 12/31/2022] Open
Abstract
The present review analyzes the results of recent clinical trials of β secretase inhibition in sporadic Alzheimer’s disease (SAD), considers the striking dichotomy between successes in tests of β-site Amyloid Precursor Protein-Cleaving Enzyme (BACE) inhibitors in healthy subjects and familial Alzheimer’s disease (FAD) models versus persistent failures of clinical trials and interprets it as a confirmation of key predictions for a mechanism of amyloid precursor protein (APP)-independent, β secretase inhibition-resistant production of β amyloid in SAD, previously proposed by us. In light of this concept, FAD and SAD should be regarded as distinctly different diseases as far as β-amyloid generation mechanisms are concerned, and whereas β secretase inhibition would be neither applicable nor effective in the treatment of SAD, the β-site APP-Cleaving Enzyme (BACE) inhibitor(s) deemed failed in SAD trials could be perfectly suitable for the treatment of FAD. Moreover, targeting the aspects of Alzheimer’s disease (AD) other than cleavages of the APP by β and α secretases should have analogous impacts in both FAD and SAD.
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Affiliation(s)
- Vladimir Volloch
- Deptartment of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA.
| | - Sophia Rits
- Howard Hughes Medical Institute at Children's Hospital, Boston, MA 02115, USA.
- Deptartment of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
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