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Signal B, Phipps AJ, Giles KA, Huskins SN, Mercer TR, Robinson MD, Woodhouse A, Taberlay PC. Ageing-Related Changes to H3K4me3, H3K27ac, and H3K27me3 in Purified Mouse Neurons. Cells 2024; 13:1393. [PMID: 39195281 DOI: 10.3390/cells13161393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2024] [Revised: 08/19/2024] [Accepted: 08/19/2024] [Indexed: 08/29/2024] Open
Abstract
Neurons are central to lifelong learning and memory, but ageing disrupts their morphology and function, leading to cognitive decline. Although epigenetic mechanisms are known to play crucial roles in learning and memory, neuron-specific genome-wide epigenetic maps into old age remain scarce, often being limited to whole-brain homogenates and confounded by glial cells. Here, we mapped H3K4me3, H3K27ac, and H3K27me3 in mouse neurons across their lifespan. This revealed stable H3K4me3 and global losses of H3K27ac and H3K27me3 into old age. We observed patterns of synaptic function gene deactivation, regulated through the loss of the active mark H3K27ac, but not H3K4me3. Alongside this, embryonic development loci lost repressive H3K27me3 in old age. This suggests a loss of a highly refined neuronal cellular identity linked to global chromatin reconfiguration. Collectively, these findings indicate a key role for epigenetic regulation in neurons that is inextricably linked with ageing.
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Affiliation(s)
- Brandon Signal
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7000, Australia
| | - Andrew J Phipps
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7000, Australia
| | - Katherine A Giles
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7000, Australia
- Children's Medical Research Institute, University of Sydney, 214 Hawkesbury Road, Westmead, NSW 2145, Australia
| | - Shannon N Huskins
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7000, Australia
| | - Timothy R Mercer
- Australian Institute for Bioengineering and Nanotechnology, Corner College and Cooper Roads, Brisbane, QLD 4072, Australia
| | - Mark D Robinson
- SIB Swiss Institute of Bioinformatics, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Adele Woodhouse
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7000, Australia
| | - Phillippa C Taberlay
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7000, Australia
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2
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Zhang H, Liu Y, Xie Y, Zhu Y, Liu J, Lu F. H3K27me3 shapes DNA methylome by inhibiting UHRF1-mediated H3 ubiquitination. SCIENCE CHINA. LIFE SCIENCES 2022; 65:1685-1700. [PMID: 35831553 DOI: 10.1007/s11427-022-2155-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
DNA methylation and histone lysine tri-methylation at H3K27 (H3K27me3) are two chromatin modifications for transcriptional gene silencing, which play important roles in diverse biological processes, including cell fate determination and cell lineage commitment. These two marks are largely mutually exclusive and target distinct sets of genes in the mammalian genome. However, how H3K27me3 shapes the DNA methylome remains elusive. Here, we report that the loss of H3K27me3 modification leads to increased DNA methylation at previously marked H3K27me3 sites, indicating that H3K27me3 negatively regulates DNA methylation. Genome-wide analysis of H3 ubiquitination, essential for recruitment and activation of DNA methyltransferase DNMT1, reveals the absence of H3 ubiquitination at H3K27me3 marked nucleosomes. Moreover, loss of H3K27me3 modification induces an increase in H3K18 ubiquitination at the corresponding hyper-methylated loci. Importantly, we show that H3K27me3 directly inhibits UHRF1-mediated H3 ubiquitination toward nucleosomes in a defined biochemical assay. Taken together, our findings reveal a general mechanism for H3K27me3-mediated shaping of the mammalian DNA methylome via modulation of H3 ubiquitination.
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Affiliation(s)
- Honglian Zhang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ying Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yali Xie
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yunji Zhu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jingwen Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Falong Lu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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3
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Karlow JA, Devarakonda S, Xing X, Jang HS, Govindan R, Watson M, Wang T. Developmental Pathways Are Epigenetically Reprogrammed during Lung Cancer Brain Metastasis. Cancer Res 2022; 82:2692-2703. [PMID: 35706127 PMCID: PMC9357144 DOI: 10.1158/0008-5472.can-21-4160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 04/13/2022] [Accepted: 06/14/2022] [Indexed: 02/05/2023]
Abstract
Non-small cell lung cancer (NSCLC) is one of the most commonly diagnosed and deadliest cancers worldwide, with roughly half of all patients initially presenting with both primary and metastatic disease. While the major events in the metastatic cascade have been identified, a mechanistic understanding of how NSCLC routinely and successfully colonizes the brain is largely unknown. Recent studies have begun demonstrating the role of epigenetic misregulation during tumorigenesis and metastasis, including widespread changes in DNA methylation and histone modifications. To better understand the role of altered DNA methylation in NSCLC metastasis to the brain, we measured DNA methylation during disease progression for 12 patients, globally profiling the methylation status of normal lung, primary lung tumor, and brain metastasis samples. The variation in methylation was similar during metastatic spread and primary tumorigenesis but less coordinated across genomic features during metastasis. The greatest recurrent changes during metastatic progression were methylation gains in DNA methylation valleys (DMV) harboring the constitutive heterochromatin mark H3K9me3 as well as bivalent marks H3K27me3 and H3K4me1. In a lymph node-derived cancer cell line, EZH2 binding within DMVs was lost, accompanied by an increase in DNA methylation, exemplifying epigenetic switching. The vast majority of the differentially methylated region-associated DMVs harbored developmental genes, suggesting that altered epigenetic regulation of developmentally important genes may confer a selective advantage during metastatic progression. The characterization of epigenetic changes during NSCLC brain metastasis identified recurrent methylation patterns that may be prognostic biomarkers and contributors to disease progression. SIGNIFICANCE Altered DNA methylation in lung cancer brain metastases corresponds with loss of EZH2 occupancy at developmental genes, which could promote stem-like phenotypes permissive of dissemination and survival in different microenvironments.
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Affiliation(s)
- Jennifer A. Karlow
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Current address: Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Current address: Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
| | - Siddhartha Devarakonda
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Xiaoyun Xing
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hyo Sik Jang
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Current address: Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Ramaswamy Govindan
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Mark Watson
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Ting Wang
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO 63108, USA
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4
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Lowe MG, Yen MR, Hsu FM, Hosohama L, Hu Z, Chitiashvili T, Hunt TJ, Gorgy I, Bernard M, Wamaitha SE, Chen PY, Clark AT. EED is required for mouse primordial germ cell differentiation in the embryonic gonad. Dev Cell 2022; 57:1482-1495.e5. [PMID: 35679863 DOI: 10.1016/j.devcel.2022.05.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 12/14/2021] [Accepted: 05/16/2022] [Indexed: 11/18/2022]
Abstract
Development of primordial germ cells (PGCs) is required for reproduction. During PGC development in mammals, major epigenetic remodeling occurs, which is hypothesized to establish an epigenetic landscape for sex-specific germ cell differentiation and gametogenesis. In order to address the role of embryonic ectoderm development (EED) and histone 3 lysine 27 trimethylation (H3K27me3) in this process, we created an EED conditional knockout mouse and show that EED is essential for regulating the timing of sex-specific PGC differentiation in both ovaries and testes, as well as X chromosome dosage decompensation in testes. Integrating chromatin and whole genome bisulfite sequencing of epiblast and PGCs, we identified a poised repressive signature of H3K27me3/DNA methylation that we propose is established in the epiblast where EED and DNMT1 interact. Thus, EED joins DNMT1 in regulating the timing of sex-specific PGC differentiation during the critical window when the gonadal niche cells specialize into an ovary or testis.
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Affiliation(s)
- Matthew G Lowe
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA 90095, USA
| | - Ming-Ren Yen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Fei-Man Hsu
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA 90095, USA
| | - Linzi Hosohama
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | - Zhongxun Hu
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | - Tsotne Chitiashvili
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA; Department of Biological Chemistry, University of California, Los Angeles, CA 90095, USA
| | - Timothy J Hunt
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | - Isaac Gorgy
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | - Matthew Bernard
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Sissy E Wamaitha
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | - Pao-Yang Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Amander T Clark
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA 90095, USA; Jonsson Comprehensive Cancer Center, University of California, Los Angeles, CA 90095, USA.
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5
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Janssen SM, Lorincz MC. Interplay between chromatin marks in development and disease. Nat Rev Genet 2022; 23:137-153. [PMID: 34608297 DOI: 10.1038/s41576-021-00416-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2021] [Indexed: 02/07/2023]
Abstract
DNA methylation (DNAme) and histone post-translational modifications (PTMs) have important roles in transcriptional regulation. Although many reports have characterized the functions of such chromatin marks in isolation, recent genome-wide studies reveal surprisingly complex interactions between them. Here, we focus on the interplay between DNAme and methylation of specific lysine residues on the histone H3 tail. We describe the impact of genetic perturbation of the relevant methyltransferases in the mouse on the landscape of chromatin marks as well as the transcriptome. In addition, we discuss the specific neurodevelopmental growth syndromes and cancers resulting from pathogenic mutations in the human orthologues of these genes. Integrating these observations underscores the fundamental importance of crosstalk between DNA and histone H3 methylation in development and disease.
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Affiliation(s)
- Sanne M Janssen
- Department of Medical Genetics, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Matthew C Lorincz
- Department of Medical Genetics, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.
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6
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Tost J. Current and Emerging Technologies for the Analysis of the Genome-Wide and Locus-Specific DNA Methylation Patterns. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1389:395-469. [DOI: 10.1007/978-3-031-11454-0_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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7
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Kanapeckaitė A, Burokienė N, Mažeikienė A, Cottrell GS, Widera D. Biophysics is reshaping our perception of the epigenome: from DNA-level to high-throughput studies. BIOPHYSICAL REPORTS 2021; 1:100028. [PMID: 36425454 PMCID: PMC9680810 DOI: 10.1016/j.bpr.2021.100028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 09/24/2021] [Indexed: 06/16/2023]
Abstract
Epigenetic research holds great promise to advance our understanding of biomarkers and regulatory processes in health and disease. An increasing number of new approaches, ranging from molecular to biophysical analyses, enable identifying epigenetic changes on the level of a single gene or the whole epigenome. The aim of this review is to highlight how the field is shifting from completely molecular-biology-driven solutions to multidisciplinary strategies including more reliance on biophysical analysis tools. Biophysics not only offers technical advancements in imaging or structure analysis but also helps to explore regulatory interactions. New computational methods are also being developed to meet the demand of growing data volumes and their processing. Therefore, it is important to capture these new directions in epigenetics from a biophysical perspective and discuss current challenges as well as multiple applications of biophysical methods and tools. Specifically, we gradually introduce different biophysical research methods by first considering the DNA-level information and eventually higher-order chromatin structures. Moreover, we aim to highlight that the incorporation of bioinformatics, machine learning, and artificial intelligence into biophysical analysis allows gaining new insights into complex epigenetic processes. The gained understanding has already proven useful in translational and clinical research providing better patient stratification options or new therapeutic insights. Together, this offers a better readiness to transform bench-top experiments into industrial high-throughput applications with a possibility to employ developed methods in clinical practice and diagnostics.
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Affiliation(s)
- Austė Kanapeckaitė
- Algorithm379, Laisvės g. 7, LT 12007, Vilnius, Lithuania
- Reading School of Pharmacy, Whiteknights, Reading, UK, RG6 6UB
| | - Neringa Burokienė
- Clinics of Internal Diseases, Family Medicine and Oncology, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, M. K. Čiurlionio str. 21/27, LT-03101 Vilnius, Lithuania
| | - Asta Mažeikienė
- Department of Physiology, Biochemistry, Microbiology and Laboratory Medicine, Institute of Biomedical Sciences, Faculty of Medicine, M. K. Čiurlionio str. 21/27, LT-03101 Vilnius, Lithuania
| | | | - Darius Widera
- Reading School of Pharmacy, Whiteknights, Reading, UK, RG6 6UB
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8
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Shi J, Xu J, Chen YE, Li JS, Cui Y, Shen L, Li JJ, Li W. The concurrence of DNA methylation and demethylation is associated with transcription regulation. Nat Commun 2021; 12:5285. [PMID: 34489442 PMCID: PMC8421433 DOI: 10.1038/s41467-021-25521-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 08/12/2021] [Indexed: 12/22/2022] Open
Abstract
The mammalian DNA methylome is formed by two antagonizing processes, methylation by DNA methyltransferases (DNMT) and demethylation by ten-eleven translocation (TET) dioxygenases. Although the dynamics of either methylation or demethylation have been intensively studied in the past decade, the direct effects of their interaction on gene expression remain elusive. Here, we quantify the concurrence of DNA methylation and demethylation by the percentage of unmethylated CpGs within a partially methylated read from bisulfite sequencing. After verifying ‘methylation concurrence’ by its strong association with the co-localization of DNMT and TET enzymes, we observe that methylation concurrence is strongly correlated with gene expression. Notably, elevated methylation concurrence in tumors is associated with the repression of 40~60% of tumor suppressor genes, which cannot be explained by promoter hypermethylation alone. Furthermore, methylation concurrence can be used to stratify large undermethylated regions with negligible differences in average methylation into two subgroups with distinct chromatin accessibility and gene regulation patterns. Together, methylation concurrence represents a unique methylation metric important for transcription regulation and is distinct from conventional metrics, such as average methylation and methylation variation. The global pattern of the mammalian methylome is formed by changes in methylation and demethylation. Here the authors describe a metric methylation concurrence that measures the ratio of unmethylated CpGs inside the partially methylated reads and show that methylation concurrence is associated with epigenetically regulated tumour suppressor genes.
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Affiliation(s)
- Jiejun Shi
- Division of Computational Biomedicine, Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Jianfeng Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Yiling Elaine Chen
- Department of Statistics, University of California, Los Angeles, CA, USA
| | - Jason Sheng Li
- Division of Computational Biomedicine, Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Ya Cui
- Division of Computational Biomedicine, Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Lanlan Shen
- Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children's Nutrition Research Center, Houston, TX, USA
| | - Jingyi Jessica Li
- Department of Statistics, University of California, Los Angeles, CA, USA
| | - Wei Li
- Division of Computational Biomedicine, Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA.
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9
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Brasil S, Neves CJ, Rijoff T, Falcão M, Valadão G, Videira PA, Dos Reis Ferreira V. Artificial Intelligence in Epigenetic Studies: Shedding Light on Rare Diseases. Front Mol Biosci 2021; 8:648012. [PMID: 34026829 PMCID: PMC8131862 DOI: 10.3389/fmolb.2021.648012] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 04/09/2021] [Indexed: 12/29/2022] Open
Abstract
More than 7,000 rare diseases (RDs) exist worldwide, affecting approximately 350 million people, out of which only 5% have treatment. The development of novel genome sequencing techniques has accelerated the discovery and diagnosis in RDs. However, most patients remain undiagnosed. Epigenetics has emerged as a promise for diagnosis and therapies in common disorders (e.g., cancer) with several epimarkers and epidrugs already approved and used in clinical practice. Hence, it may also become an opportunity to uncover new disease mechanisms and therapeutic targets in RDs. In this “big data” age, the amount of information generated, collected, and managed in (bio)medicine is increasing, leading to the need for its rapid and efficient collection, analysis, and characterization. Artificial intelligence (AI), particularly deep learning, is already being successfully applied to analyze genomic information in basic research, diagnosis, and drug discovery and is gaining momentum in the epigenetic field. The application of deep learning to epigenomic studies in RDs could significantly boost discovery and therapy development. This review aims to collect and summarize the application of AI tools in the epigenomic field of RDs. The lower number of studies found, specific for RDs, indicate that this is a field open to expansion, following the results obtained for other more common disorders.
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Affiliation(s)
- Sandra Brasil
- Portuguese Association for CDG, Lisbon, Portugal.,CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
| | - Cátia José Neves
- Portuguese Association for CDG, Lisbon, Portugal.,CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
| | - Tatiana Rijoff
- Portuguese Association for CDG, Lisbon, Portugal.,CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
| | - Marta Falcão
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Gonçalo Valadão
- Instituto de Telecomunicações, Lisbon, Portugal.,Departamento de Ciências e Tecnologias, Autónoma Techlab - Universidade Autónoma de Lisboa, Lisbon, Portugal.,Electronics, Telecommunications and Computers Engineering Department, Instituto Superior de Engenharia de Lisboa, Lisbon, Portugal
| | - Paula A Videira
- Portuguese Association for CDG, Lisbon, Portugal.,CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal.,UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Vanessa Dos Reis Ferreira
- Portuguese Association for CDG, Lisbon, Portugal.,CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
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10
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Yang Y, Li G. Post-translational modifications of PRC2: signals directing its activity. Epigenetics Chromatin 2020; 13:47. [PMID: 33129354 PMCID: PMC7603765 DOI: 10.1186/s13072-020-00369-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 10/23/2020] [Indexed: 12/23/2022] Open
Abstract
Polycomb repressive complex 2 (PRC2) is a chromatin-modifying enzyme that catalyses the methylation of histone H3 at lysine 27 (H3K27me1/2/3). This complex maintains gene transcriptional repression and plays an essential role in the maintenance of cellular identity as well as normal organismal development. The activity of PRC2, including its genomic targeting and catalytic activity, is controlled by various signals. Recent studies have revealed that these signals involve cis chromatin features, PRC2 facultative subunits and post-translational modifications (PTMs) of PRC2 subunits. Overall, these findings have provided insight into the biochemical signals directing PRC2 function, although many mysteries remain.
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Affiliation(s)
- Yiqi Yang
- Faculty of Health Sciences, University of Macau, Macau, China.,Cancer Centre, Faculty of Health Sciences, University of Macau, Macau, China.,Centre of Reproduction, Development and Aging, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, China
| | - Gang Li
- Faculty of Health Sciences, University of Macau, Macau, China. .,Cancer Centre, Faculty of Health Sciences, University of Macau, Macau, China. .,Centre of Reproduction, Development and Aging, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, China.
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11
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Li Y. Modern epigenetics methods in biological research. Methods 2020; 187:104-113. [PMID: 32645449 DOI: 10.1016/j.ymeth.2020.06.022] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/23/2020] [Accepted: 06/29/2020] [Indexed: 01/09/2023] Open
Abstract
The definition of epigenetics refers that molecular modifications on DNA that can regulate gene activity are independent of DNA sequence and mitotically stable. Notably, epigenetics studies have grown exponentially in the past few years. Recent progresses that lead to exciting discoveries and groundbreaking nature of this area demand thorough methodologies and advanced technologies to move epigenetics to the forefront of molecular biology. The most recognized epigenetic regulations are DNA methylation, histone modifications, and non-coding RNAs (ncRNAs). This review will discuss the modern techniques that are available to detect locus-specific and genome-wide changes for all epigenetic codes. Furthermore, updated analysis of technologies, newly developed methods, recent breakthroughs and bioinformatics pipelines in epigenetic analysis will be presented. These methods, as well as many others presented in this specific issue, provide comprehensive guidelines in the area of epigenetics that facilitate further developments in this promising and rapidly developing field.
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Affiliation(s)
- Yuanyuan Li
- Department of Obstetrics, Gynecology & Women's Heath, University of Missouri, Columbia, MO 65212, USA; Department of Surgery, University of Missouri, Columbia, MO 65212, USA.
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12
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Deng C, Naler LB, Lu C. Microfluidic epigenomic mapping technologies for precision medicine. LAB ON A CHIP 2019; 19:2630-2650. [PMID: 31338502 PMCID: PMC6697104 DOI: 10.1039/c9lc00407f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Epigenomic mapping of tissue samples generates critical insights into genome-wide regulations of gene activities and expressions during normal development and disease processes. Epigenomic profiling using a low number of cells produced by patient and mouse samples presents new challenges to biotechnologists. In this review, we first discuss the rationale and premise behind profiling epigenomes for precision medicine. We then examine the existing literature on applying microfluidics to facilitate low-input and high-throughput epigenomic profiling, with emphasis on technologies enabling interfacing with next-generation sequencing. We detail assays on studies of histone modifications, DNA methylation, 3D chromatin structures and non-coding RNAs. Finally, we discuss what the future may hold in terms of method development and translational potential.
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Affiliation(s)
- Chengyu Deng
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA.
| | - Lynette B Naler
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA.
| | - Chang Lu
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA.
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13
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Liu B, Pilarsky C. Analysis of DNA Hypermethylation in Pancreatic Cancer Using Methylation-Specific PCR and Bisulfite Sequencing. Methods Mol Biol 2019; 1856:269-282. [PMID: 30178258 DOI: 10.1007/978-1-4939-8751-1_16] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive tumor and the fourth common cause of cancer death in the Western world. The lack of effective therapeutic strategies is attributed to the late diagnosis of this disease. Methylation markers could improve early detection and help in the surveillance of PDAC after treatment. Analysis of hypermethylation in the tumor tissue and tumor-derived exosomes might help to identify new therapeutic strategies and aid in the understanding of the pathophysiological changes occurring in pancreatic cancer. There are several methods for the detection of methylation events. Whereas methylation-specific PCR (MSP-PCR) is the method of choice, the cost reductions in DNA sequencing enables researchers to add bisulfite sequencing (BSS) to their repertoire if a small number of genes will be tested in a larger set of patients' samples. During the last years, several techniques to isolate and analyze DNA methylation have been proposed, but DNA modification using sodium bisulfite is still the gold standard.
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Affiliation(s)
- Bin Liu
- Department of Surgery, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen, Erlangen, Germany
| | - Christian Pilarsky
- Department of Surgery, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen, Erlangen, Germany.
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Sendžikaitė G, Hanna CW, Stewart-Morgan KR, Ivanova E, Kelsey G. A DNMT3A PWWP mutation leads to methylation of bivalent chromatin and growth retardation in mice. Nat Commun 2019; 10:1884. [PMID: 31015495 PMCID: PMC6478690 DOI: 10.1038/s41467-019-09713-w] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/26/2019] [Indexed: 11/08/2022] Open
Abstract
DNA methyltransferases (DNMTs) deposit DNA methylation, which regulates gene expression and is essential for mammalian development. Histone post-translational modifications modulate the recruitment and activity of DNMTs. The PWWP domains of DNMT3A and DNMT3B are posited to interact with histone 3 lysine 36 trimethylation (H3K36me3); however, the functionality of this interaction for DNMT3A remains untested in vivo. Here we present a mouse model carrying a D329A point mutation in the DNMT3A PWWP domain. The mutation causes dominant postnatal growth retardation. At the molecular level, it results in progressive DNA hypermethylation across domains marked by H3K27me3 and bivalent chromatin, and de-repression of developmental regulatory genes in adult hypothalamus. Evaluation of non-CpG methylation, a marker of de novo methylation, further demonstrates the altered recruitment and activity of DNMT3AD329A at bivalent domains. This work provides key molecular insights into the function of the DNMT3A-PWWP domain and role of DNMT3A in regulating postnatal growth.
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Affiliation(s)
| | - Courtney W Hanna
- Epigenetics Programme, Babraham Institute, Cambridge, CB22 3AT, UK
- Centre for Trophoblast Research, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Kathleen R Stewart-Morgan
- Epigenetics Programme, Babraham Institute, Cambridge, CB22 3AT, UK
- Biotech Research & Innovation Centre, 2200, Copenhagen, Denmark
| | - Elena Ivanova
- Epigenetics Programme, Babraham Institute, Cambridge, CB22 3AT, UK
| | - Gavin Kelsey
- Epigenetics Programme, Babraham Institute, Cambridge, CB22 3AT, UK.
- Centre for Trophoblast Research, University of Cambridge, Cambridge, CB2 3EG, UK.
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15
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Möller M, Schotanus K, Soyer JL, Haueisen J, Happ K, Stralucke M, Happel P, Smith KM, Connolly LR, Freitag M, Stukenbrock EH. Destabilization of chromosome structure by histone H3 lysine 27 methylation. PLoS Genet 2019; 15:e1008093. [PMID: 31009462 PMCID: PMC6510446 DOI: 10.1371/journal.pgen.1008093] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 05/10/2019] [Accepted: 03/15/2019] [Indexed: 01/23/2023] Open
Abstract
Chromosome and genome stability are important for normal cell function as instability often correlates with disease and dysfunction of DNA repair mechanisms. Many organisms maintain supernumerary or accessory chromosomes that deviate from standard chromosomes. The pathogenic fungus Zymoseptoria tritici has as many as eight accessory chromosomes, which are highly unstable during meiosis and mitosis, transcriptionally repressed, show enrichment of repetitive elements, and enrichment with heterochromatic histone methylation marks, e.g., trimethylation of H3 lysine 9 or lysine 27 (H3K9me3, H3K27me3). To elucidate the role of heterochromatin on genome stability in Z. tritici, we deleted the genes encoding the methyltransferases responsible for H3K9me3 and H3K27me3, kmt1 and kmt6, respectively, and generated a double mutant. We combined experimental evolution and genomic analyses to determine the impact of these deletions on chromosome and genome stability, both in vitro and in planta. We used whole genome sequencing, ChIP-seq, and RNA-seq to compare changes in genome and chromatin structure, and differences in gene expression between mutant and wildtype strains. Analyses of genome and ChIP-seq data in H3K9me3-deficient strains revealed dramatic chromatin reorganization, where H3K27me3 is mostly relocalized into regions that are enriched with H3K9me3 in wild type. Many genome rearrangements and formation of new chromosomes were found in the absence of H3K9me3, accompanied by activation of transposable elements. In stark contrast, loss of H3K27me3 actually increased the stability of accessory chromosomes under normal growth conditions in vitro, even without large scale changes in gene activity. We conclude that H3K9me3 is important for the maintenance of genome stability because it disallows H3K27me3 in regions considered constitutive heterochromatin. In this system, H3K27me3 reduces the overall stability of accessory chromosomes, generating a "metastable" state for these quasi-essential regions of the genome.
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Affiliation(s)
- Mareike Möller
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Fellow Group Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Klaas Schotanus
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States of America
| | - Jessica L. Soyer
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | - Janine Haueisen
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Fellow Group Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Kathrin Happ
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
| | - Maja Stralucke
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
| | - Petra Happel
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Kristina M. Smith
- Department of Biology, Oregon State University—Cascades, Bend, OR, United States of America
| | - Lanelle R. Connolly
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, United States of America
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, United States of America
| | - Eva H. Stukenbrock
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Fellow Group Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
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16
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Lee JR, Ooi CC, Wang SX. In Vitro Cancer Diagnostics. Bioanalysis 2019. [DOI: 10.1007/978-3-030-01775-0_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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17
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Heck C, Michaeli Y, Bald I, Ebenstein Y. Analytical epigenetics: single-molecule optical detection of DNA and histone modifications. Curr Opin Biotechnol 2018; 55:151-158. [PMID: 30326408 DOI: 10.1016/j.copbio.2018.09.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/12/2018] [Accepted: 09/16/2018] [Indexed: 12/13/2022]
Abstract
The field of epigenetics describes the relationship between genotype and phenotype, by regulating gene expression without changing the canonical base sequence of DNA. It deals with molecular genomic information that is encoded by a rich repertoire of chemical modifications and molecular interactions. This regulation involves DNA, RNA and proteins that are enzymatically tagged with small molecular groups that alter their physical and chemical properties. It is now clear that epigenetic alterations are involved in development and disease, and thus, are the focus of intensive research. The ability to record epigenetic changes and quantify them in rare medical samples is critical for next generation diagnostics. Optical detection offers the ultimate single-molecule sensitivity and the potential for spectral multiplexing. Here we review recent progress in ultrasensitive optical detection of DNA and histone modifications.
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Affiliation(s)
- Christian Heck
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel; Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Yael Michaeli
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ilko Bald
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany; BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Str. 11, 12489 Berlin, Germany.
| | - Yuval Ebenstein
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel.
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18
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Insight into origins, mechanisms, and utility of DNA methylation in B-cell malignancies. Blood 2018; 132:999-1006. [PMID: 30037886 DOI: 10.1182/blood-2018-02-692970] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 07/15/2018] [Indexed: 12/12/2022] Open
Abstract
Understanding how tumor cells fundamentally alter their identity is critical to identify specific vulnerabilities for use in precision medicine. In B-cell malignancy, knowledge of genetic changes has resulted in great gains in our understanding of the biology of tumor cells, impacting diagnosis, prognosis, and treatment. Despite this knowledge, much remains to be explained as genetic events do not completely explain clinical behavior and outcomes. Many patients lack recurrent driver mutations, and said drivers can persist in nonmalignant cells of healthy individuals remaining cancer-free for decades. Epigenetics has emerged as a valuable avenue to further explain tumor phenotypes. The epigenetic landscape is the software that powers and stabilizes cellular identity by abridging a broad genome into the essential information required per cell. A genome-level view of B-cell malignancies reveals complex but recurrent epigenetic patterns that define tumor types and subtypes, permitting high-resolution classification and novel insight into tumor-specific mechanisms. Epigenetic alterations are guided by distinct cellular processes, such as polycomb-based silencing, transcription, signaling pathways, and transcription factor activity, and involve B-cell-specific aspects, such as activation-induced cytidine deaminase activity and germinal center-specific events. Armed with a detailed knowledge of the epigenetic events that occur across the spectrum of B-cell differentiation, B-cell tumor-specific aberrations can be detected with improved accuracy and serve as a model for identification of tumor-specific events in cancer. Insight gained through recent efforts may prove valuable in guiding the use of both epigenetic- and nonepigenetic-based therapies.
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Abstract
Epigenetic complexes regulate chromatin dynamics via binding to and assembling on chromatin. However, the mechanisms of chromatin binding and assembly of epigenetic complexes within cells remain incompletely understood, partly due to technical challenges. Here, we present a new approach termed single-molecule chromatin immunoprecipitation imaging (Sm-ChIPi) that enables to assess the cellular assembly stoichiometry of epigenetic complexes on chromatin. Sm-ChIPi was developed based on chromatin immunoprecipitation followed by single-molecule fluorescence microscopy imaging. In this method, an epigenetic complex subunit fused with a gene coding for a fluorescent protein is stably expressed in its corresponding knockout cells. Nucleosomes associated with epigenetic complexes are isolated from cells at native conditions and incubated with biotinylated antibodies. The resulting complexes are immobilized on a quartz slide that had been passivated and functionalized with NeutrAvidin. Image stacks are then acquired by using single-molecule TIRF microscopy. The individual spots imaged by TIRF microscopy represent single protein-nucleosome complexes. The number of copies of the protein complexes on a nucleosome is inferred from the fluorescence photobleaching measurements. Sm-ChIPi is a sensitive and direct method that can quantify the cellular assembly stoichiometry of epigenetic complexes on chromatin.
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Affiliation(s)
- Roubina Tatavosian
- Department of Chemistry, University of Colorado Denver, Denver, CO, 80217-3364, USA
| | - Xiaojun Ren
- Department of Chemistry, University of Colorado Denver, Renovated Science Building, Rm 3071, 1151 Arapahoe Street, Denver, CO, 80204, USA.
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20
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Li Y, Zheng H, Wang Q, Zhou C, Wei L, Liu X, Zhang W, Zhang Y, Du Z, Wang X, Xie W. Genome-wide analyses reveal a role of Polycomb in promoting hypomethylation of DNA methylation valleys. Genome Biol 2018; 19:18. [PMID: 29422066 PMCID: PMC5806489 DOI: 10.1186/s13059-018-1390-8] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 01/10/2018] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Previous studies showed that the majority of developmental genes are devoid of DNA methylation at promoters even when they are repressed. Such hypomethylated regions at developmental genes are unusually large and extend well beyond proximal promoters, forming DNA methylation valleys (DMVs) or DNA methylation canyons. However, it remains elusive how most developmental genes can evade DNA methylation regardless of their transcriptional states. RESULTS We show that DMVs are hypomethylated in development and are highly conserved across vertebrates. Importantly, DMVs are hotspots of regulatory regions for key developmental genes and show low levels of deamination mutation rates. By analyzing a panel of DNA methylomes from mouse tissues, we identify a subset of DMVs that are dynamically methylated. These DMVs are strongly enriched for Polycomb-deposited H3K27me3 when the associated genes are silenced, and surprisingly show elevated DNA methylation upon gene activation. 4C-seq analyses indicates that Polycomb-bound DMVs form insulated and self-interacting chromatin domains. Further investigations show that DNA hypomethylation is better correlated with the binding of Polycomb than with H3K27me3. In support of a role of Polycomb in DMV hypomethylation, we observe aberrant methylation in DMVs in mouse embryonic stem cells deficient in the EED protein. Finally, we show that Polycomb regulates hypomethylation of DMVs likely through ten-eleven translocation (TET) proteins. CONCLUSIONS We show that Polycomb promotes the hypomethylation of DMVs near key developmental genes. These data reveal a delicate interplay between histone modifiers and DNA methylation, which contributes to their division at distinct gene targets, allowing lineage-specifying genes to largely maintain DNA methylation-free at regulatory elements.
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Affiliation(s)
- Yuanyuan Li
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Hui Zheng
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Qiujun Wang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Chen Zhou
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Lei Wei
- Bioinformatics Division, TNLIST/MOE Key Laboratory of Bioinformatics, Center for Synthetic and System Biology, Department of Automation, Tsinghua University, Beijing, 100084, China
| | - Xuehui Liu
- Bioinformatics Division, TNLIST/MOE Key Laboratory of Bioinformatics, Center for Synthetic and System Biology, Department of Automation, Tsinghua University, Beijing, 100084, China
| | - Wenhao Zhang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yu Zhang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Zhenhai Du
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xiaowo Wang
- Bioinformatics Division, TNLIST/MOE Key Laboratory of Bioinformatics, Center for Synthetic and System Biology, Department of Automation, Tsinghua University, Beijing, 100084, China
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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21
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Xu Q, Xie W. Epigenome in Early Mammalian Development: Inheritance, Reprogramming and Establishment. Trends Cell Biol 2017; 28:237-253. [PMID: 29217127 DOI: 10.1016/j.tcb.2017.10.008] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/25/2017] [Accepted: 10/27/2017] [Indexed: 01/17/2023]
Abstract
Drastic epigenetic reprogramming takes place during preimplantation development, leading to the conversion of terminally differentiated gametes to a totipotent embryo. Deficiencies in remodeling of the epigenomes can cause severe developmental defects, including embryonic lethality. However, how chromatin modifications and chromatin organization are reprogrammed upon fertilization in mammals has long remained elusive. Here, we review recent progress in understanding how the epigenome is dynamically regulated during early mammalian development. The latest studies, including many from genome-wide perspectives, have revealed unusual principles of reprogramming for histone modifications, chromatin accessibility, and 3D chromatin architecture. These advances have shed light on the regulatory network controlling the earliest development and maternal-zygotic transition.
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Affiliation(s)
- Qianhua Xu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, THU-PKU Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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22
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Zeeshan R, Mutahir Z. Cancer metastasis - tricks of the trade. Bosn J Basic Med Sci 2017; 17:172-182. [PMID: 28278128 DOI: 10.17305/bjbms.2017.1908] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 01/21/2017] [Accepted: 01/22/2017] [Indexed: 12/18/2022] Open
Abstract
Decades of cancer research have unraveled genetic, epigenetic and molecular pathways leading to plausible therapeutic targets; many of which hold great promise in improving clinical outcomes. Metastatic tumors become evident early on and are one of the major causes of cancer-related fatalities worldwide. This review depicts the sequential events of cancer metastasis. Genetic and epigenetic heterogeneity influences local tumor cell invasion, intravasation, survival in circulation, extravasation and colonization to distant sites. Each sequential event is associated with heterogeneous tumor microenvironment, gain of competence, unique population of cancer stem cells (CSCs), circulatory pathway, compatible niche and immune system support. A tight regulation of metastasis-promoting mechanisms and, in parallel, evading inhibitory mechanisms contribute to the severity and site of metastasis. A comprehensive understanding of tumor cell fate as an individual entity, as well as in combination with different promoting factors and associated molecular mechanisms, is anticipated in the coming years. This will enable scientists to depict design strategies for targeted cancer therapies.
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Affiliation(s)
- Rabia Zeeshan
- Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, Lahore, Pakistan.
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23
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A Tox21 Approach to Altered Epigenetic Landscapes: Assessing Epigenetic Toxicity Pathways Leading to Altered Gene Expression and Oncogenic Transformation In Vitro. Int J Mol Sci 2017; 18:ijms18061179. [PMID: 28587163 PMCID: PMC5486002 DOI: 10.3390/ijms18061179] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 05/19/2017] [Accepted: 05/22/2017] [Indexed: 02/07/2023] Open
Abstract
An emerging vision for toxicity testing in the 21st century foresees in vitro assays assuming the leading role in testing for chemical hazards, including testing for carcinogenicity. Toxicity will be determined by monitoring key steps in functionally validated molecular pathways, using tests designed to reveal chemically-induced perturbations that lead to adverse phenotypic endpoints in cultured human cells. Risk assessments would subsequently be derived from the causal in vitro endpoints and concentration vs. effect data extrapolated to human in vivo concentrations. Much direct experimental evidence now shows that disruption of epigenetic processes by chemicals is a carcinogenic mode of action that leads to altered gene functions playing causal roles in cancer initiation and progression. In assessing chemical safety, it would therefore be advantageous to consider an emerging class of carcinogens, the epigenotoxicants, with the ability to change chromatin and/or DNA marks by direct or indirect effects on the activities of enzymes (writers, erasers/editors, remodelers and readers) that convey the epigenetic information. Evidence is reviewed supporting a strategy for in vitro hazard identification of carcinogens that induce toxicity through disturbance of functional epigenetic pathways in human somatic cells, leading to inactivated tumour suppressor genes and carcinogenesis. In the context of human cell transformation models, these in vitro pathway measurements ensure high biological relevance to the apical endpoint of cancer. Four causal mechanisms participating in pathways to persistent epigenetic gene silencing were considered: covalent histone modification, nucleosome remodeling, non-coding RNA interaction and DNA methylation. Within these four interacting mechanisms, 25 epigenetic toxicity pathway components (SET1, MLL1, KDM5, G9A, SUV39H1, SETDB1, EZH2, JMJD3, CBX7, CBX8, BMI, SUZ12, HP1, MPP8, DNMT1, DNMT3A, DNMT3B, TET1, MeCP2, SETDB2, BAZ2A, UHRF1, CTCF, HOTAIR and ANRIL) were found to have experimental evidence showing that functional perturbations played “driver” roles in human cellular transformation. Measurement of epigenotoxicants presents challenges for short-term carcinogenicity testing, especially in the high-throughput modes emphasized in the Tox21 chemicals testing approach. There is need to develop and validate in vitro tests to detect both, locus-specific, and genome-wide, epigenetic alterations with causal links to oncogenic cellular phenotypes. Some recent examples of cell-based high throughput chemical screening assays are presented that have been applied or have shown potential for application to epigenetic endpoints.
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Intragenic CpG islands play important roles in bivalent chromatin assembly of developmental genes. Proc Natl Acad Sci U S A 2017; 114:E1885-E1894. [PMID: 28223506 DOI: 10.1073/pnas.1613300114] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
CpG, 5'-C-phosphate-G-3', islands (CGIs) have long been known for their association with enhancers, silencers, and promoters, and for their epigenetic signatures. They are maintained in embryonic stem cells (ESCs) in a poised but inactive state via the formation of bivalent chromatin containing both active and repressive marks. CGIs also occur within coding sequences, where their functional role has remained obscure. Intragenic CGIs (iCGIs) are largely absent from housekeeping genes, but they are found in all genes associated with organ development and cell lineage control. In this paper, we investigated the epigenetic status of iCGIs and found that they too reside in bivalent chromatin in ESCs. Cell type-specific DNA methylation of iCGIs in differentiated cells was linked to the loss of both the H3K4me3 and H3K27me3 marks, and disruption of physical interaction with promoter regions, resulting in transcriptional activation of key regulators of differentiation such as PAXs, HOXs, and WNTs. The differential epigenetic modification of iCGIs appears to be mediated by cell type-specific transcription factors distinct from those bound by promoter, and these transcription factors may be involved in the hypermethylation of iCGIs upon cell differentiation. iCGIs thus play a key role in the cell type-specific regulation of transcription.
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Gan Y, Tao H, Guan J, Zhou S. iHMS: a database integrating human histone modification data across developmental stages and tissues. BMC Bioinformatics 2017; 18:103. [PMID: 28187703 PMCID: PMC5303264 DOI: 10.1186/s12859-017-1461-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 01/03/2017] [Indexed: 11/17/2022] Open
Abstract
Background Differences in chromatin states are critical to the multiplicity of cell states. Recently genome-wide histone modification maps of diverse human developmental stages and tissues have been charted. Description To facilitate the investigation of epigenetic dynamics and regulatory mechanisms in cellular differentiation processes, we developed iHMS, an integrated human histone modification database that incorporates massive histone modification maps spanning different developmental stages, lineages and tissues (http://www.tongjidmb.com/human/index.html). It also includes genome-wide expression data of different conditions, reference gene annotations, GC content and CpG island information. By providing an intuitive and user-friendly query interface, iHMS enables comprehensive query and comparative analysis based on gene names, genomic region locations, histone modification marks and cell types. Moreover, it offers an efficient browser that allows users to visualize and compare multiple genome-wide histone modification maps and related expression profiles across different developmental stages and tissues. Conclusion iHMS is of great helpfulness to understand how global histone modification state transitions impact cellular phenotypes across different developmental stages and tissues in the human genome. This extensive catalog of histone modification states thus presents an important resource for epigenetic and developmental studies.
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Affiliation(s)
- Yanglan Gan
- School of Computer Science and Technology, Donghua University, Shanghai, China
| | - Han Tao
- Department of Computer Science and Technology, Tongji University, Shanghai, China
| | - Jihong Guan
- Department of Computer Science and Technology, Tongji University, Shanghai, China.
| | - Shuigeng Zhou
- Shanghai Key Lab of Intelligent Information Processing and School of Computer Science, Fudan University, Shanghai, China
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26
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Qian M, Wang DC, Chen H, Cheng Y. Detection of single cell heterogeneity in cancer. Semin Cell Dev Biol 2016; 64:143-149. [PMID: 27619166 DOI: 10.1016/j.semcdb.2016.09.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 09/08/2016] [Indexed: 11/19/2022]
Abstract
Single cell heterogeneity has already been highlighted in cancer classification, diagnosis, and treatment. Recent advanced technologies have gained more ability to reveal the heterogeneity on single cell level. In this review, we listed various detection targets applied in single cell study, including tumor tissue cells, circulating tumor cells (CTCs), disseminated tumor cells (DTCs), circulating tumor DNA (ctDNA), cell-free DNA (cfDNA), and cancer stem cells (CSCs). We further discussed and compared detection methods using these detection targets in different fields to reveal single cell heterogeneity in cancer. We focused not only on the methods that have already been established and validated, but also on newly developed methods. In morphology and phenotype, the methods mainly included cell imaging and immune-staining. In genomics and proteomics, the main methods were single cell sequencing and single cell western blotting. Collectively, from using these methods, we can have a better understanding of the single cell variation, as well as what kind of variation it is and how the variation works. Our observations imply that study on single cell heterogeneity in cancer is an important step to precision medicine. The development of technologies in detection of single cell heterogeneity will be sure to improve the diagnosis and treatment in cancer.
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Affiliation(s)
- Mengjia Qian
- Zhongshan Hospital Institute of Clinical Science, Fudan University, Shanghai 200032, China
| | - Diane C Wang
- Zhongshan Hospital Institute of Clinical Science, Fudan University, Shanghai 200032, China.
| | - Hao Chen
- Department of Cardiothoracic Surgery, Tongji Hospital, Tongji University School of Medicine, Shanghai, 200065, China
| | - Yunfeng Cheng
- Department of Hematology, Zhongshan Hospital Fudan University, Shanghai 200032, China; Department of Hematology, Zhongshan Hospital Qingpu Branch, Fudan University, Shanghai, 201700, China.
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27
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Sun H. A multi-layer microchip for high-throughput single-cell gene expression profiling. Anal Biochem 2016; 508:1-8. [DOI: 10.1016/j.ab.2016.05.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 05/21/2016] [Accepted: 05/23/2016] [Indexed: 10/21/2022]
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Defining, distinguishing and detecting the contribution of heterogeneous methylation to cancer heterogeneity. Semin Cell Dev Biol 2016; 64:5-17. [PMID: 27582426 DOI: 10.1016/j.semcdb.2016.08.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 08/24/2016] [Indexed: 01/07/2023]
Abstract
DNA methylation is a fundamental means of epigenetic gene regulation that occurs in virtually all cell types. In many higher organisms, including humans, it plays vital roles in cell differentiation and homeostatic maintenance of cell phenotype. The control of DNA methylation has traditionally been attributed to a highly coordinated, linear process, whose dysregulation has been associated with numerous pathologies including cancer, where it occurs early in, and even prior to, the development of neoplastic tissues. Recent experimental evidence has demonstrated that, contrary to prevailing paradigms, methylation patterns are actually maintained through inexact, dynamic processes. These processes normally result in minor stochastic differences between cells that accumulate with age. However, various factors, including cancer itself, can lead to substantial differences in intercellular methylation patterns, viz. methylation heterogeneity. Advancements in molecular biology techniques are just now beginning to allow insight into how this heterogeneity contributes to clonal evolution and overall cancer heterogeneity. In the current review, we begin by presenting a didactic overview of how the basal bimodal methylome is established and maintained. We then provide a synopsis of some of the factors that lead to the accrual of heterogeneous methylation and how this heterogeneity may lead to gene silencing and impact the development of cancerous phenotypes. Lastly, we highlight currently available methylation assessment techniques and discuss their suitability to the study of heterogeneous methylation.
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Schwämmle V, Sidoli S, Ruminowicz C, Wu X, Lee CF, Helin K, Jensen ON. Systems Level Analysis of Histone H3 Post-translational Modifications (PTMs) Reveals Features of PTM Crosstalk in Chromatin Regulation. Mol Cell Proteomics 2016; 15:2715-29. [PMID: 27302890 DOI: 10.1074/mcp.m115.054460] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Indexed: 12/21/2022] Open
Abstract
Histones are abundant chromatin constituents carrying numerous post-translational modifications (PTMs). Such PTMs mediate a variety of biological functions, including recruitment of enzymatic readers, writers and erasers that modulate DNA replication, transcription and repair. Individual histone molecules contain multiple coexisting PTMs, some of which exhibit crosstalk, i.e. coordinated or mutually exclusive activities. Here, we present an integrated experimental and computational systems level molecular characterization of histone PTMs and PTM crosstalk. Using wild type and engineered mouse embryonic stem cells (mESCs) knocked out in components of the Polycomb Repressive Complex 2 (PRC2, Suz12(-/-)), PRC1 (Ring1A/B(-/-)) and (Dnmt1/3a/3b(-/-)) we performed comprehensive PTM analysis of histone H3 tails (50 aa) by utilizing quantitative middle-down proteome analysis by tandem mass spectrometry. We characterized combinatorial PTM features across the four mESC lines and then applied statistical data analysis to predict crosstalk between histone H3 PTMs. We detected an overrepresentation of positive crosstalk (codependent marks) between adjacent mono-methylated and acetylated marks, and negative crosstalk (mutually exclusive marks) among most of the seven characterized di- and tri-methylated lysine residues in the H3 tails. We report novel features of PTM interplay involving hitherto poorly characterized arginine methylation and lysine methylation sites, including H3R2me, H3R8me and H3K37me. Integration of the H3 data with RNAseq data by coabundance clustering analysis of histone PTMs and histone modifying enzymes revealed correlations between PTM and enzyme levels. We conclude that middle-down proteomics is a powerful tool to determine conserved or dynamic interdependencies between histone marks, which paves the way for detailed investigations of the histone code. Histone H3 PTM data is publicly available in the CrossTalkDB repository at http://crosstalkdb.bmb.sdu.dk.
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Affiliation(s)
- Veit Schwämmle
- From the ‡Centre for Epigenetics and VILLUM Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark;
| | - Simone Sidoli
- From the ‡Centre for Epigenetics and VILLUM Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Chrystian Ruminowicz
- From the ‡Centre for Epigenetics and VILLUM Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Xudong Wu
- §Biotech Research and Innovation Centre and Centre for Epigenetics, University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - Chung-Fan Lee
- §Biotech Research and Innovation Centre and Centre for Epigenetics, University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - Kristian Helin
- §Biotech Research and Innovation Centre and Centre for Epigenetics, University of Copenhagen, DK-2200, Copenhagen, Denmark; ¶The Danish Stem Cell Centre (Danstem), University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - Ole N Jensen
- From the ‡Centre for Epigenetics and VILLUM Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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30
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Shema E, Jones D, Shoresh N, Donohue L, Ram O, Bernstein BE. Single-molecule decoding of combinatorially modified nucleosomes. Science 2016; 352:717-21. [PMID: 27151869 DOI: 10.1126/science.aad7701] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 04/06/2016] [Indexed: 12/21/2022]
Abstract
Different combinations of histone modifications have been proposed to signal distinct gene regulatory functions, but this area is poorly addressed by existing technologies. We applied high-throughput single-molecule imaging to decode combinatorial modifications on millions of individual nucleosomes from pluripotent stem cells and lineage-committed cells. We identified definitively bivalent nucleosomes with concomitant repressive and activating marks, as well as other combinatorial modification states whose prevalence varies with developmental potency. We showed that genetic and chemical perturbations of chromatin enzymes preferentially affect nucleosomes harboring specific modification states. Last, we combined this proteomic platform with single-molecule DNA sequencing technology to simultaneously determine the modification states and genomic positions of individual nucleosomes. This single-molecule technology has the potential to address fundamental questions in chromatin biology and epigenetic regulation.
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Affiliation(s)
- Efrat Shema
- Department of Pathology and Center for Cancer Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA. Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Noam Shoresh
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Laura Donohue
- Department of Pathology and Center for Cancer Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA. Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Oren Ram
- Department of Pathology and Center for Cancer Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA. Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Bradley E Bernstein
- Department of Pathology and Center for Cancer Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA. Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
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31
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Abstract
Hundreds of distinct chemical modifications to DNA and histone amino acids have been described. Regulation exerted by these so-called epigenetic marks is vital to normal development, stability of cell identity through mitosis, and nongenetic transmission of traits between generations through meiosis. Loss of this regulation contributes to many diseases. Evidence indicates epigenetic marks function in combinations, whereby a given modification has distinct effects on local genome control, depending on which additional modifications are locally present. This review summarizes emerging methods for assessing combinatorial epigenomic states, as well as challenges and opportunities for their refinement.
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Affiliation(s)
- Paul D. Soloway
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853, United States
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32
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Friedrich SM, Zec HC, Wang TH. Analysis of single nucleic acid molecules in micro- and nano-fluidics. LAB ON A CHIP 2016; 16:790-811. [PMID: 26818700 PMCID: PMC4767527 DOI: 10.1039/c5lc01294e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Nucleic acid analysis has enhanced our understanding of biological processes and disease progression, elucidated the association of genetic variants and disease, and led to the design and implementation of new treatment strategies. These diverse applications require analysis of a variety of characteristics of nucleic acid molecules: size or length, detection or quantification of specific sequences, mapping of the general sequence structure, full sequence identification, analysis of epigenetic modifications, and observation of interactions between nucleic acids and other biomolecules. Strategies that can detect rare or transient species, characterize population distributions, and analyze small sample volumes enable the collection of richer data from biosamples. Platforms that integrate micro- and nano-fluidic operations with high sensitivity single molecule detection facilitate manipulation and detection of individual nucleic acid molecules. In this review, we will highlight important milestones and recent advances in single molecule nucleic acid analysis in micro- and nano-fluidic platforms. We focus on assessment modalities for single nucleic acid molecules and highlight the role of micro- and nano-structures and fluidic manipulation. We will also briefly discuss future directions and the current limitations and obstacles impeding even faster progress toward these goals.
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Affiliation(s)
- Sarah M Friedrich
- Biomedical Engineering Department, Johns Hopkins University, Baltimore, MD 21218, USA.
| | - Helena C Zec
- Mechanical Engineering Department, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Tza-Huei Wang
- Biomedical Engineering Department, Johns Hopkins University, Baltimore, MD 21218, USA. and Mechanical Engineering Department, Johns Hopkins University, Baltimore, MD 21218, USA
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33
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Current and Emerging Technologies for the Analysis of the Genome-Wide and Locus-Specific DNA Methylation Patterns. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 945:343-430. [DOI: 10.1007/978-3-319-43624-1_15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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34
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Pilarsky C, Nanduri LK, Roy J. Gene Expression Analysis in the Age of Mass Sequencing: An Introduction. Methods Mol Biol 2015; 1381:67-73. [PMID: 26667455 DOI: 10.1007/978-1-4939-3204-7_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
During the last years the technology used for gene expression analysis has changed dramatically. The old mainstay, DNA microarray, has served its due course and will soon be replaced by next-generation sequencing (NGS), the Swiss army knife of modern high-throughput nucleic acid-based analysis. Therefore preparation technologies have to adapt to suit the emerging NGS technology platform. Moreover, interpretation of the results is still time consuming and employs the use of high-end computers usually not found in molecular biology laboratories. Alternatively, cloud computing might solve this problem. Nevertheless, these new challenges have to be embraced for gene expression analysis in general.
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Affiliation(s)
- Christian Pilarsky
- Department of Surgery, TU Dresden, Fetscherstr. 74, Dresden, 01307, Germany.
| | | | - Janine Roy
- Biotechnology Center, Technische Universität Dresden, Tatzberg 47-49, Dresden, 01307, Germany
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35
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Genome-wide redistribution of H3K27me3 is linked to genotoxic stress and defective growth. Proc Natl Acad Sci U S A 2015; 112:E6339-48. [PMID: 26578794 DOI: 10.1073/pnas.1511377112] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
H3K9 methylation directs heterochromatin formation by recruiting multiple heterochromatin protein 1 (HP1)-containing complexes that deacetylate histones and methylate cytosine bases in DNA. In Neurospora crassa, a single H3K9 methyltransferase complex, called the DIM-5,-7,-9, CUL4, DDB1 Complex (DCDC), is required for normal growth and development. DCDC-deficient mutants are hypersensitive to the genotoxic agent methyl methanesulfonate (MMS), but the molecular basis of genotoxic stress is unclear. We found that both the MMS sensitivity and growth phenotypes of DCDC-deficient strains are suppressed by mutation of embryonic ectoderm development or Su-(var)3-9; E(z); Trithorax (set)-7, encoding components of the H3K27 methyltransferase Polycomb repressive complex-2 (PRC2). Trimethylated histone H3K27 (H3K27me3) undergoes genome-wide redistribution to constitutive heterochromatin in DCDC- or HP1-deficient mutants, and introduction of an H3K27 missense mutation is sufficient to rescue phenotypes of DCDC-deficient strains. Accumulation of H3K27me3 in heterochromatin does not compensate for silencing; rather, strains deficient for both DCDC and PRC2 exhibit synthetic sensitivity to the topoisomerase I inhibitor Camptothecin and accumulate γH2A at heterochromatin. Together, these data suggest that PRC2 modulates the response to genotoxic stress.
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36
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Gao F, Das SK. Epigenetic regulations through DNA methylation and hydroxymethylation: clues for early pregnancy in decidualization. Biomol Concepts 2015; 5:95-107. [PMID: 25372745 DOI: 10.1515/bmc-2013-0036] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/04/2014] [Indexed: 12/25/2022] Open
Abstract
DNA methylation at cytosines is an important epigenetic modification that participates in gene expression regulation without changing the original DNA sequence. With the rapid progress of high-throughput sequencing techniques, whole-genome distribution of methylated cytosines and their regulatory mechanism have been revealed gradually. This has allowed the uncovering of the critical roles played by DNA methylation in the maintenance of cell pluripotency, determination of cell fate during development, and in diverse diseases. Recently, rediscovery of 5-hydroxymethylcytosine, and other types of modification on DNA, have uncovered more dynamic aspects of cell methylome regulation. The interaction of DNA methylation and other epigenetic changes remodel the chromatin structure and determine the state of gene transcription, not only permanently, but also transiently under certain stimuli. The uterus is a reproductive organ that experiences dramatic hormone stimulated changes during the estrous cycle and pregnancy, and thus provides us with a unique model for studying the dynamic regulation of epigenetic modifications. In this article, we review the current findings on the roles of genomic DNA methylation and hydroxymethylation in the regulation of gene expression, and discuss the progress of studies for these epigenetic changes in the uterus during implantation and decidualization.
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37
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Rotem A, Ram O, Shoresh N, Sperling RA, Goren A, Weitz DA, Bernstein BE. Single-cell ChIP-seq reveals cell subpopulations defined by chromatin state. Nat Biotechnol 2015; 33:1165-72. [PMID: 26458175 PMCID: PMC4636926 DOI: 10.1038/nbt.3383] [Citation(s) in RCA: 597] [Impact Index Per Article: 66.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 09/21/2015] [Indexed: 12/27/2022]
Abstract
Chromatin profiling provides a versatile means to investigate functional genomic elements and their regulation. However, current methods yield ensemble profiles that are insensitive to cell-to-cell variation. Here we combine microfluidics, DNA barcoding and sequencing to collect chromatin data at single-cell resolution. We demonstrate the utility of the technology by assaying thousands of individual cells, and using the data to deconvolute a mixture of ES cells, fibroblasts and hematopoietic progenitors into high-quality chromatin state maps for each cell type. The data from each single cell is sparse, comprising on the order of 1000 unique reads. However, by assaying thousands of ES cells, we identify a spectrum of sub-populations defined by differences in chromatin signatures of pluripotency and differentiation priming. We corroborate these findings by comparison to orthogonal single-cell gene expression data. Our method for single-cell analysis reveals aspects of epigenetic heterogeneity not captured by transcriptional analysis alone.
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Affiliation(s)
- Assaf Rotem
- Department of Physics and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA.,Epigenomics Program, The Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Oren Ram
- Epigenomics Program, The Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.,Howard Hughes Medical Institute, Chevy Chase, Maryland, USA.,Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Noam Shoresh
- Epigenomics Program, The Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Ralph A Sperling
- Department of Physics and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
| | - Alon Goren
- Broad Technology Labs, The Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - David A Weitz
- Department of Physics and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
| | - Bradley E Bernstein
- Epigenomics Program, The Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.,Howard Hughes Medical Institute, Chevy Chase, Maryland, USA.,Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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38
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Switching between Epigenetic States at Pericentromeric Heterochromatin. Trends Genet 2015; 31:661-672. [PMID: 26431676 DOI: 10.1016/j.tig.2015.09.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/21/2015] [Accepted: 09/04/2015] [Indexed: 02/05/2023]
Abstract
Pericentromeric DNA represents a large fraction of the mammalian genome that is usually assembled into heterochromatin. Recent advances have revealed that the composition of pericentromeric heterochromatin is surprisingly dynamic. Indeed, high levels of histone H3 trimethylation on lysine 9 (H3K9me3) and DNA methylation normally characterize the repressive environment of this region. However, in specific tissues and in cancer cells, Polycomb proteins can occupy pericentromeric heterochromatin and act as a molecular sink for transcriptional regulators. Restoring heterochromatin methylation marks could, thus, be an important way to bring back normal gene expression programs in disease. Here, I discuss the potential mechanisms by which Polycomb complexes are recruited to pericentromeric DNA.
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39
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Tatavosian R, Zhen CY, Duc HN, Balas MM, Johnson AM, Ren X. Distinct Cellular Assembly Stoichiometry of Polycomb Complexes on Chromatin Revealed by Single-molecule Chromatin Immunoprecipitation Imaging. J Biol Chem 2015; 290:28038-28054. [PMID: 26381410 DOI: 10.1074/jbc.m115.671115] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Indexed: 12/11/2022] Open
Abstract
Epigenetic complexes play an essential role in regulating chromatin structure, but information about their assembly stoichiometry on chromatin within cells is poorly understood. The cellular assembly stoichiometry is critical for appreciating the initiation, propagation, and maintenance of epigenetic inheritance during normal development and in cancer. By combining genetic engineering, chromatin biochemistry, and single-molecule fluorescence imaging, we developed a novel and sensitive approach termed single-molecule chromatin immunoprecipitation imaging (Sm-ChIPi) to enable investigation of the cellular assembly stoichiometry of epigenetic complexes on chromatin. Sm-ChIPi was validated by using chromatin complexes with known stoichiometry. The stoichiometry of subunits within a polycomb complex and the assembly stoichiometry of polycomb complexes on chromatin have been extensively studied but reached divergent views. Moreover, the cellular assembly stoichiometry of polycomb complexes on chromatin remains unexplored. Using Sm-ChIPi, we demonstrated that within mouse embryonic stem cells, one polycomb repressive complex (PRC) 1 associates with multiple nucleosomes, whereas two PRC2s can bind to a single nucleosome. Furthermore, we obtained direct physical evidence that the nucleoplasmic PRC1 is monomeric, whereas PRC2 can dimerize in the nucleoplasm. We showed that ES cell differentiation induces selective alteration of the assembly stoichiometry of Cbx2 on chromatin but not other PRC1 components. We additionally showed that the PRC2-mediated trimethylation of H3K27 is not required for the assembly stoichiometry of PRC1 on chromatin. Thus, these findings uncover that PRC1 and PRC2 employ distinct mechanisms to assemble on chromatin, and the novel Sm-ChIPi technique could provide single-molecule insight into other epigenetic complexes.
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Affiliation(s)
- Roubina Tatavosian
- Department of Chemistry, University of Colorado Denver, Denver, Colorado 80217-3364
| | - Chao Yu Zhen
- Department of Chemistry, University of Colorado Denver, Denver, Colorado 80217-3364
| | - Huy Nguyen Duc
- Department of Chemistry, University of Colorado Denver, Denver, Colorado 80217-3364
| | - Maggie M Balas
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Aaron M Johnson
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Xiaojun Ren
- Department of Chemistry, University of Colorado Denver, Denver, Colorado 80217-3364.
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40
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Zillner K, Komatsu J, Filarsky K, Kalepu R, Bensimon A, Németh A. Active human nucleolar organizer regions are interspersed with inactive rDNA repeats in normal and tumor cells. Epigenomics 2015; 7:363-78. [PMID: 26077426 DOI: 10.2217/epi.14.93] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
AIM The synthesis of rRNA is a key determinant of normal and malignant cell growth and subject to epigenetic regulation. Yet, the epigenomic features of rDNA arrays clustered in nucleolar organizer regions are largely unknown. We set out to explore for the first time how DNA methylation is distributed on individual rDNA arrays. MATERIALS & METHODS Here we combined immunofluorescence detection of DNA modifications with fluorescence hybridization of single DNA fibers, metaphase immuno-FISH and methylation-sensitive restriction enzyme digestions followed by Southern blot. RESULTS We found clustering of both hypomethylated and hypermethylated repeat units and hypermethylation of noncanonical rDNA in IMR90 fibroblasts and HCT116 colorectal carcinoma cells. Surprisingly, we also found transitions between hypo- and hypermethylated rDNA repeat clusters on single DNA fibers. CONCLUSION Collectively, our analyses revealed co-existence of different epialleles on individual nucleolar organizer regions and showed that epi-combing is a valuable approach to analyze epigenomic patterns of repetitive DNA.
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Affiliation(s)
- Karina Zillner
- Department of Biochemistry III, Biochemistry Center Regensburg, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Jun Komatsu
- Genomic Vision, 80 Rue des Meuniers, 92220 Bagneux, France
| | - Katharina Filarsky
- Department of Biochemistry III, Biochemistry Center Regensburg, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.,German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Rajakiran Kalepu
- Department of Biochemistry III, Biochemistry Center Regensburg, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.,University Hospital Ulm, Ulm 89070, Germany
| | - Aaron Bensimon
- Genomic Vision, 80 Rue des Meuniers, 92220 Bagneux, France
| | - Attila Németh
- Department of Biochemistry III, Biochemistry Center Regensburg, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
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41
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Alizadeh AA, Aranda V, Bardelli A, Blanpain C, Bock C, Borowski C, Caldas C, Califano A, Doherty M, Elsner M, Esteller M, Fitzgerald R, Korbel JO, Lichter P, Mason CE, Navin N, Pe'er D, Polyak K, Roberts CWM, Siu L, Snyder A, Stower H, Swanton C, Verhaak RGW, Zenklusen JC, Zuber J, Zucman-Rossi J. Toward understanding and exploiting tumor heterogeneity. Nat Med 2015; 21:846-53. [PMID: 26248267 PMCID: PMC4785013 DOI: 10.1038/nm.3915] [Citation(s) in RCA: 502] [Impact Index Per Article: 55.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 07/01/2015] [Indexed: 11/09/2022]
Abstract
The extent of tumor heterogeneity is an emerging theme that researchers are only beginning to understand. How genetic and epigenetic heterogeneity affects tumor evolution and clinical progression is unknown. The precise nature of the environmental factors that influence this heterogeneity is also yet to be characterized. Nature Medicine, Nature Biotechnology and the Volkswagen Foundation organized a meeting focused on identifying the obstacles that need to be overcome to advance translational research in and tumor heterogeneity. Once these key questions were established, the attendees devised potential solutions. Their ideas are presented here.
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Affiliation(s)
- Ash A Alizadeh
- 1] Division of Oncology, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA. [2] Division of Hematology, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA. [3] Cancer Institute, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | | | - Alberto Bardelli
- 1] Department of Oncology, University of Torino, Candiolo, Torino, Italy. [2] Candiolo Cancer Institute-Fondazione del Piemonte per l'Oncologia (FPO), IRCCS, Candiolo, Torino, Italy
| | | | - Christoph Bock
- 1] CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria. [2] Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | | | - Carlos Caldas
- Department of Oncology, University of Cambridge, Cambridge, UK
| | - Andrea Califano
- 1] Department of Systems Biology, Columbia University, New York, New York, USA. [2] Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, USA. [3] Department of Biomedical Informatics, Columbia University, New York, New York, USA
| | | | | | - Manel Esteller
- Cancer Epigenetics and Biology Program, Bellvitge Biomedical Research Institute, Barcelona, Catalonia, Spain
| | - Rebecca Fitzgerald
- MRC Cancer Unit, Hutchison-MRC Research Centre, University of Cambridge, Cambridge, UK
| | - Jan O Korbel
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Peter Lichter
- German Cancer Research Center, DKFZ, Heidelberg, Germany
| | | | - Nicholas Navin
- 1] Department of Genetics, MD Anderson Cancer Center, Houston, Texas, USA. [2] Department of Bioinformatics and Computational Biology, MD Anderson Cancer Center, Houston, Texas, USA
| | - Dana Pe'er
- 1] Department of Systems Biology, Columbia University, New York, New York, USA. [2] Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Kornelia Polyak
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Charles W M Roberts
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Lillian Siu
- Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Alexandra Snyder
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | | | - Charles Swanton
- 1] University College London Cancer Institute, London, UK. [2] University College London Hospitals NHS Foundation Trust, London, UK. [3] The Francis Crick Institute, London, UK
| | - Roel G W Verhaak
- 1] Department of Bioinformatics and Computational Biology, MD Anderson Cancer Center, Houston, Texas, USA. [2] Department of Genomic Medicine, MD Anderson Cancer Center, Houston, Texas, USA
| | - Jean C Zenklusen
- The Cancer Genome Atlas, Center for Cancer Genomics, National Cancer Institute, Bethesda, Maryland, USA
| | - Johannes Zuber
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Jessica Zucman-Rossi
- Inserm, UMR-1162, Génomique fonctionnelle des tumeurs solides, Institut Universitaire d'Hématologie (IUH), Paris, France
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Schmid M, Smith J, Burt DW, Aken BL, Antin PB, Archibald AL, Ashwell C, Blackshear PJ, Boschiero C, Brown CT, Burgess SC, Cheng HH, Chow W, Coble DJ, Cooksey A, Crooijmans RPMA, Damas J, Davis RVN, de Koning DJ, Delany ME, Derrien T, Desta TT, Dunn IC, Dunn M, Ellegren H, Eöry L, Erb I, Farré M, Fasold M, Fleming D, Flicek P, Fowler KE, Frésard L, Froman DP, Garceau V, Gardner PP, Gheyas AA, Griffin DK, Groenen MAM, Haaf T, Hanotte O, Hart A, Häsler J, Hedges SB, Hertel J, Howe K, Hubbard A, Hume DA, Kaiser P, Kedra D, Kemp SJ, Klopp C, Kniel KE, Kuo R, Lagarrigue S, Lamont SJ, Larkin DM, Lawal RA, Markland SM, McCarthy F, McCormack HA, McPherson MC, Motegi A, Muljo SA, Münsterberg A, Nag R, Nanda I, Neuberger M, Nitsche A, Notredame C, Noyes H, O'Connor R, O'Hare EA, Oler AJ, Ommeh SC, Pais H, Persia M, Pitel F, Preeyanon L, Prieto Barja P, Pritchett EM, Rhoads DD, Robinson CM, Romanov MN, Rothschild M, Roux PF, Schmidt CJ, Schneider AS, Schwartz MG, Searle SM, Skinner MA, Smith CA, Stadler PF, Steeves TE, Steinlein C, Sun L, Takata M, Ulitsky I, Wang Q, Wang Y, Warren WC, Wood JMD, Wragg D, Zhou H. Third Report on Chicken Genes and Chromosomes 2015. Cytogenet Genome Res 2015; 145:78-179. [PMID: 26282327 PMCID: PMC5120589 DOI: 10.1159/000430927] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Michael Schmid
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
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Recent advances and current issues in single-cell sequencing of tumors. Cancer Lett 2015; 365:1-10. [PMID: 26003306 DOI: 10.1016/j.canlet.2015.04.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 04/19/2015] [Accepted: 04/20/2015] [Indexed: 12/28/2022]
Abstract
Intratumoral heterogeneity is a recently recognized but important feature of cancer that underlies the various biocharacteristics of cancer tissues. The advent of next-generation sequencing technologies has facilitated large scale capture of genomic data, while the recent development of single-cell sequencing has allowed for more in-depth studies into the complex molecular mechanisms of intratumoral heterogeneity. In this review, the recent advances and current challenges in single-cell sequencing methodologies are discussed, highlighting the potential power of these data to provide insights into oncological processes, from tumorigenesis through progression to metastasis and therapy resistance.
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Chromatin modifications and genomic contexts linked to dynamic DNA methylation patterns across human cell types. Sci Rep 2015; 5:8410. [PMID: 25673498 PMCID: PMC4325317 DOI: 10.1038/srep08410] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 01/19/2015] [Indexed: 12/29/2022] Open
Abstract
DNA methylation is related closely to sequence contexts and chromatin modifications; however, their potential differences in different genomic regions across cell types remain largely unexplored. We used publicly available genome-scale DNA methylation and histone modification profiles to study their relationships among different genomic regions in human embryonic stem cells (H1), H1-derived neuronal progenitor cultured cells (NPC), and foetal fibroblasts (IMR90) using the Random forests classifier. Histone modifications achieved high accuracy in modelling DNA methylation patterns on a genome scale in the three cell types. The inclusion of sequence features helped improve accuracy only in non-promoter regions of IMR90. Furthermore, the top six feature combinations obtained by mean decrease Gini were important indicators of different DNA methylation patterns, suggesting that H3K4me2 and H3K4me3 are important indicators that are independent of genomic regions and cell types. H3K9me3 was IMR90-specific and exhibited a genomic region-specific correlation with DNA methylation. Variations of essential chromatin modification signals may effectively discriminate changes of DNA methylation between H1 and IMR90. Genes with different co-variations of epigenetic marks exhibited genomic region-specific biological relevance. This study provides an integrated strategy to identify systematically essential epigenetic and genetic elements of genomic region-specific and cell type-specific DNA methylation patterns.
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Zhou LQ, Dean J. Reprogramming the genome to totipotency in mouse embryos. Trends Cell Biol 2015; 25:82-91. [PMID: 25448353 PMCID: PMC4312727 DOI: 10.1016/j.tcb.2014.09.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/17/2014] [Accepted: 09/23/2014] [Indexed: 02/03/2023]
Abstract
Despite investigative interest, the artificial derivation of pluripotent stem cells remains inefficient and incomplete reprogramming hinders its potential as a reliable tool in regenerative medicine. By contrast, fusion of terminally differentiated gametes at fertilization activates efficient epigenetic reprogramming to ensure totipotency of early embryos. Understanding the epigenetic mechanisms required for the transition from the fertilized egg to the embryo can improve efforts to reprogram differentiated cells to pluripotent/totipotent cells for therapeutic use. We review recent discoveries that are providing insight into the molecular mechanisms required for epigenetic reprogramming to totipotency in vivo.
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Affiliation(s)
- Li-quan Zhou
- Laboratory of Cellular and Developmental Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jurrien Dean
- Laboratory of Cellular and Developmental Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA.
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Abstract
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive tumor and the fourth common cause of cancer death in the Western world. The lack of effective therapeutic strategies is due to the late diagnosis of this disease. Methylation markers could improve early detection and help in the surveillance of PDAC after treatment. Analysis of hypermethylation in the tumor tissue might help to identify new therapeutic strategies and aid in the understanding of the pathophysiological changes occurring in pancreatic cancer. There are several methods for the detection of methylated events, but methylation-specific PCR (MSP-PCR) is the method of choice if a small number of genes will be tested in a larger set of patients samples. After isolation of the DNA by standard procedure, the DNA is then modified using sodium bisulfide.
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Affiliation(s)
- Christian Pilarsky
- Department of Surgery, Medizinische Fakultät Carl Gustav Carus, TU Dresden, Fetscherstr. 74, 01307, Dresden, Germany,
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Takeshima H, Wakabayashi M, Hattori N, Yamashita S, Ushijima T. Identification of coexistence of DNA methylation and H3K27me3 specifically in cancer cells as a promising target for epigenetic therapy. Carcinogenesis 2014; 36:192-201. [PMID: 25477340 DOI: 10.1093/carcin/bgu238] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Alterations of epigenetic modifications are promising targets for cancer therapy, and several epigenetic drugs are now being clinically utilized. At the same time, individual epigenetic modifications have physiological functions in normal cells, and cancer cell specificity is considered difficult to achieve using a drug against a single epigenetic modification. To overcome this limitation, a combination of epigenetic modifications specifically or preferentially present in cancer cells is a candidate target. In this study, we aimed to demonstrate (i) the presence of a cancer cell-specific combination of epigenetic modifications by focusing on DNA methylation and trimethylation of histone H3 lysine 27 (H3K27me3) and (ii) the therapeutic efficacy of a combination of DNA demethylation and EZH2 inhibition. Analyses of DNA methylation and H3K27me3 in human colon, breast and prostate cancer cell lines revealed that 24.7±4.1% of DNA methylated genes had both DNA methylation and H3K27me3 (dual modification) in cancer cells, while it was 11.8±7.1% in normal cells. Combined treatment with a DNA demethylating agent, 5-aza-2'-deoxycytidine (5-aza-dC) and an EZH2 inhibitor, GSK126, induced marked re-expression of genes with the dual modification, including known tumor-suppressor genes such as IGFBP7 and SFRP1, and showed an additive inhibitory effect on growth of cancer cells in vitro. Finally, an in vivo combined treatment with 5-aza-dC and GSK126 inhibited growth of xenograft tumors more efficiently than a single treatment with 5-aza-dC. These results showed that the dual modification exists specifically in cancer cells and is a promising target for cancer cell-specific epigenetic therapy.
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Affiliation(s)
- Hideyuki Takeshima
- Division of Epigenomics, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
| | - Mika Wakabayashi
- Division of Epigenomics, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
| | - Naoko Hattori
- Division of Epigenomics, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
| | - Satoshi Yamashita
- Division of Epigenomics, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
| | - Toshikazu Ushijima
- Division of Epigenomics, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
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van der Maarel JRC, Zhang C, van Kan JA. A Nanochannel Platform for Single DNA Studies: From Crowding, Protein DNA Interaction, to Sequencing of Genomic Information. Isr J Chem 2014. [DOI: 10.1002/ijch.201400091] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Hyun BR, McElwee JL, Soloway PD. Single molecule and single cell epigenomics. Methods 2014; 72:41-50. [PMID: 25204781 DOI: 10.1016/j.ymeth.2014.08.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Revised: 08/19/2014] [Accepted: 08/27/2014] [Indexed: 01/24/2023] Open
Abstract
Dynamically regulated changes in chromatin states are vital for normal development and can produce disease when they go awry. Accordingly, much effort has been devoted to characterizing these states under normal and pathological conditions. Chromatin immunoprecipitation followed by sequencing (ChIP-seq) is the most widely used method to characterize where in the genome transcription factors, modified histones, modified nucleotides and chromatin binding proteins are found; bisulfite sequencing (BS-seq) and its variants are commonly used to characterize the locations of DNA modifications. Though very powerful, these methods are not without limitations. Notably, they are best at characterizing one chromatin feature at a time, yet chromatin features arise and function in combination. Investigators commonly superimpose separate ChIP-seq or BS-seq datasets, and then infer where chromatin features are found together. While these inferences might be correct, they can be misleading when the chromatin source has distinct cell types, or when a given cell type exhibits any cell to cell variation in chromatin state. These ambiguities can be eliminated by robust methods that directly characterize the existence and genomic locations of combinations of chromatin features in very small inputs of cells or ideally, single cells. Here we review single molecule epigenomic methods under development to overcome these limitations, the technical challenges associated with single molecule methods and their potential application to single cells.
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Affiliation(s)
- Byung-Ryool Hyun
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - John L McElwee
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Paul D Soloway
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA.
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Gurard-Levin ZA, Almouzni G. Histone modifications and a choice of variant: a language that helps the genome express itself. F1000PRIME REPORTS 2014; 6:76. [PMID: 25343033 PMCID: PMC4166940 DOI: 10.12703/p6-76] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Covalent post-translational modifications on histones impact chromatin structure and function. Their misfunction, along with perturbations or mutations in genes that regulate their dynamic status, has been observed in several diseases. Thus, targeting histone modifications represents attractive opportunities for therapeutic intervention and biomarker discovery. The best approach to address this challenge is to paint a comprehensive picture integrating the growing number of modifications on individual residues and their combinatorial association, the corresponding modifying enzymes, and effector proteins that bind modifications. Furthermore, how they are imposed in a distinct manner during the cell cycle and on specific histone variants are important dimensions to consider. Firstly, this report highlights innovative technologies used to characterize histone modifications, and the corresponding enzymes and effector proteins. Secondly, we examine the recent progress made in understanding the dynamics and maintenance of histone modifications on distinct variants. We also discuss their roles as potential carriers of epigenetic information. Finally, we provide examples of initiatives to exploit histone modifications in cancer management, with the potential for new therapeutic opportunities.
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Affiliation(s)
- Zachary A. Gurard-Levin
- Institut Curie, Centre de RechercheParis, F-75248France
- CNRS, UMR3664Paris, F-75248France
- Équipe Labellisée Ligue contre le Cancer, UMR3664Paris, F-75248France
- UPMC, UMR3664Paris, F-75248France
- Sorbonne University, PSLParisFrance
| | - Geneviève Almouzni
- Institut Curie, Centre de RechercheParis, F-75248France
- CNRS, UMR3664Paris, F-75248France
- Équipe Labellisée Ligue contre le Cancer, UMR3664Paris, F-75248France
- UPMC, UMR3664Paris, F-75248France
- Sorbonne University, PSLParisFrance
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