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Sunitha Kumary VUN, Venters BJ, Raman K, Sen S, Estève PO, Cowles MW, Keogh MC, Pradhan S. Emerging Approaches to Profile Accessible Chromatin from Formalin-Fixed Paraffin-Embedded Sections. EPIGENOMES 2024; 8:20. [PMID: 38804369 PMCID: PMC11130958 DOI: 10.3390/epigenomes8020020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 05/06/2024] [Indexed: 05/29/2024] Open
Abstract
Nucleosomes are non-uniformly distributed across eukaryotic genomes, with stretches of 'open' chromatin strongly associated with transcriptionally active promoters and enhancers. Understanding chromatin accessibility patterns in normal tissue and how they are altered in pathologies can provide critical insights to development and disease. With the advent of high-throughput sequencing, a variety of strategies have been devised to identify open regions across the genome, including DNase-seq, MNase-seq, FAIRE-seq, ATAC-seq, and NicE-seq. However, the broad application of such methods to FFPE (formalin-fixed paraffin-embedded) tissues has been curtailed by the major technical challenges imposed by highly fixed and often damaged genomic material. Here, we review the most common approaches for mapping open chromatin regions, recent optimizations to overcome the challenges of working with FFPE tissue, and a brief overview of a typical data pipeline with analysis considerations.
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Affiliation(s)
| | - Bryan J. Venters
- EpiCypher Inc., Durham, NC 27709, USA; (V.U.N.S.K.); (B.J.V.); (M.W.C.)
| | - Karthikeyan Raman
- Genome Biology Division, New England Biolabs, Ipswich, MA 01983, USA; (K.R.); (S.S.); (P.-O.E.)
| | - Sagnik Sen
- Genome Biology Division, New England Biolabs, Ipswich, MA 01983, USA; (K.R.); (S.S.); (P.-O.E.)
| | - Pierre-Olivier Estève
- Genome Biology Division, New England Biolabs, Ipswich, MA 01983, USA; (K.R.); (S.S.); (P.-O.E.)
| | - Martis W. Cowles
- EpiCypher Inc., Durham, NC 27709, USA; (V.U.N.S.K.); (B.J.V.); (M.W.C.)
| | | | - Sriharsa Pradhan
- Genome Biology Division, New England Biolabs, Ipswich, MA 01983, USA; (K.R.); (S.S.); (P.-O.E.)
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2
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Chin HG, Vishnu US, Sun Z, Ponnaluri VKC, Zhang G, Xu SY, Benoukraf T, Cejas P, Spracklin G, Estève PO, Long HW, Pradhan S. Universal NicE-Seq: A Simple and Quick Method for Accessible Chromatin Detection in Fixed Cells. Methods Mol Biol 2023; 2611:39-52. [PMID: 36807062 DOI: 10.1007/978-1-0716-2899-7_3] [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: 02/23/2023]
Abstract
Genome-wide accessible chromatin sequencing and identification has enabled deciphering the epigenetic information encoded in chromatin, revealing accessible promoters, enhancers, nucleosome positioning, transcription factor occupancy, and other chromosomal protein binding. The starting biological materials are often fixed using formaldehyde crosslinking. Here, we describe accessible chromatin library preparation from low numbers of formaldehyde-crosslinked cells using a modified nick translation method, where a nicking enzyme nicks one strand of DNA and DNA polymerase incorporates biotin-conjugated dATP, dCTP, and methyl-dCTP. Once the DNA is labeled, it can be isolated for NGS library preparation. We termed this method as universal NicE-seq (nicking enzyme-assisted sequencing). We also demonstrate a single tube method that enables direct NGS library preparation from low cell numbers without DNA purification. Furthermore, we demonstrated universal NicE-seq on FFPE tissue section sample.
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Affiliation(s)
| | | | - Zhiyi Sun
- New England Biolabs Inc., Ipswich, MA, USA
| | | | | | | | - Touati Benoukraf
- Faculty of Medicine, Craig L. Dobbin Genetics Research Centre, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Paloma Cejas
- Center for Functional Cancer Epigenetics, Dana-Farber Cancer Institute, Boston, MA, USA
| | - George Spracklin
- Program in Systems Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | | | - Henry W Long
- Center for Functional Cancer Epigenetics, Dana-Farber Cancer Institute, Boston, MA, USA
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3
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Estève PO, Vishnu US, Chin HG, Pradhan S. NicE-viewSeq: An Integrative Visualization and Genomics Method to Detect Accessible Chromatin in Fixed Cells. Methods Mol Biol 2023; 2611:293-302. [PMID: 36807075 DOI: 10.1007/978-1-0716-2899-7_16] [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] [Indexed: 02/23/2023]
Abstract
A novel genome-wide accessible chromatin visualization, quantitation, and sequencing method is described, which allows in situ fluorescence visualization and sequencing of the accessible chromatin in the mammalian cell. The cells are fixed by formaldehyde crosslinking, and processed using a modified nick translation method, where a nicking enzyme nicks one strand of DNA, and DNA polymerase incorporates biotin-conjugated dCTP, 5-methyl-dCTP, Fluorescein-12-dATP or Texas Red-5-dATP, dGTP, and dTTP. This allows accessible chromatin DNA to be labeled for visualization and on bead NGS library preparation. This technology allows cellular level chromatin accessibility quantification and genomic analysis of the epigenetic information in the chromatin, particularly accessible promoter, enhancers, nucleosome positioning, transcription factor occupancy, and other chromosomal protein binding.
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Affiliation(s)
| | | | - Hang Gyeong Chin
- Genome Biology Division, New England Biolabs, Inc., Ipswich, MA, USA
| | - Sriharsa Pradhan
- Genome Biology Division, New England Biolabs, Inc., Ipswich, MA, USA.
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4
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Grandi FC, Modi H, Kampman L, Corces MR. Chromatin accessibility profiling by ATAC-seq. Nat Protoc 2022; 17:1518-1552. [PMID: 35478247 DOI: 10.1038/s41596-022-00692-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 02/22/2022] [Indexed: 12/13/2022]
Abstract
The assay for transposase-accessible chromatin using sequencing (ATAC-seq) provides a simple and scalable way to detect the unique chromatin landscape associated with a cell type and how it may be altered by perturbation or disease. ATAC-seq requires a relatively small number of input cells and does not require a priori knowledge of the epigenetic marks or transcription factors governing the dynamics of the system. Here we describe an updated and optimized protocol for ATAC-seq, called Omni-ATAC, that is applicable across a broad range of cell and tissue types. The ATAC-seq workflow has five main steps: sample preparation, transposition, library preparation, sequencing and data analysis. This protocol details the steps to generate and sequence ATAC-seq libraries, with recommendations for sample preparation and downstream bioinformatic analysis. ATAC-seq libraries for roughly 12 samples can be generated in 10 h by someone familiar with basic molecular biology, and downstream sequencing analysis can be implemented using benchmarked pipelines by someone with basic bioinformatics skills and with access to a high-performance computing environment.
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Affiliation(s)
- Fiorella C Grandi
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA.,Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA.,Department of Neurology, University of California San Francisco, San Francisco, CA, USA
| | - Hailey Modi
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA.,Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA.,Department of Neurology, University of California San Francisco, San Francisco, CA, USA
| | - Lucas Kampman
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA.,Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA.,Department of Neurology, University of California San Francisco, San Francisco, CA, USA
| | - M Ryan Corces
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA. .,Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA. .,Department of Neurology, University of California San Francisco, San Francisco, CA, USA.
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5
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Luo Z, Zhang R, Hu T, Zhu Y, Wu Y, Li W, Zhang Z, Yao X, Liang H, Song X. NicE-C efficiently reveals open chromatin-associated chromosome interactions at high resolution. Genome Res 2022; 32:534-544. [PMID: 35105668 PMCID: PMC8896462 DOI: 10.1101/gr.275986.121] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 01/25/2022] [Indexed: 11/24/2022]
Abstract
Enhancer–promoter communication is known to regulate spatiotemporal dynamics of gene expression. Several methods are available to capture enhancer–promoter interactions, but they either require large amounts of starting materials and are costly, or provide a relative low resolution in chromatin contact maps. Here, we present nicking enzyme-assisted open chromatin interaction capture (NicE-C), a method that leverages nicking enzyme–mediated open chromatin profiling and chromosome conformation capture to enable robust and cost-effective detection of open chromatin interactions at high resolution, especially enhancer–promoter interactions. Using TNF stimulation and mouse kidney aging as models, we applied NicE-C to reveal characteristics of dynamic enhancer–promoter interactions.
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Affiliation(s)
- Zhengyu Luo
- MOE Key Laboratory for Cellular Dynamics, CAS Key Laboratory of Brain Function and Disease, University of Science and Technology of China
| | - Ran Zhang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China
| | - Tengfei Hu
- MOE Key Laboratory for Cellular Dynamics, CAS Key Laboratory of Brain Function and Disease, University of Science and Technology of China
| | - Yuting Zhu
- MOE Key Laboratory for Cellular Dynamics, CAS Key Laboratory of Brain Function and Disease, University of Science and Technology of China
| | - Yueming Wu
- MOE Key Laboratory for Cellular Dynamics, CAS Key Laboratory of Brain Function and Disease, University of Science and Technology of China
| | - Wenfei Li
- Affiliated Psychological Hospital of Anhui Medical University, Hefei Fourth People's Hospital, Anhui Mental Health Center
| | - Zhi Zhang
- CAS Key Laboratory of Brain Function and Disease, University of Science and Technology of China
| | - Xuebiao Yao
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Anhui Key Laboratory for Cellular Dynamics and Chemical Biology
| | - Haiyi Liang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China
| | - Xiaoyuan Song
- MOE Key Laboratory for Cellular Dynamics, CAS Key Laboratory of Brain Function and Disease, University of Science and Technology of China;
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6
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Vishnu US, Estève PO, Chin HG, Pradhan S. One-pot universal NicE-seq: all enzymatic downstream processing of 4% formaldehyde crosslinked cells for chromatin accessibility genomics. Epigenetics Chromatin 2021; 14:53. [PMID: 34895293 PMCID: PMC8665596 DOI: 10.1186/s13072-021-00427-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 11/16/2021] [Indexed: 11/20/2022] Open
Abstract
Background Accessible chromatin landscape allows binding of transcription factors, and remodeling of promoter and enhancer elements during development. Chromatin accessibility along with integrated multiomics approaches have been used for determining molecular subtypes of cancer in patient samples. Results One-pot Universal NicE-seq (One-pot UniNicE-seq) is an improved accessible chromatin profiling method that negate DNA purification and incorporate sonication free enzymatic fragmentation before library preparation and is suited to a variety of mammalian cells. One-pot UniNicE-seq is versatile, capable of profiling 4% formaldehyde fixed chromatin in as low as 25 fixed cells. Accessible chromatin profile is more efficient on formaldehyde-fixed cells using one-pot UniNicE-seq compared to Tn5 transposon mediated methods, demonstrating its versatility. Conclusion One-pot UniNicE-seq allows the entire process of accessible chromatin labeling and enrichment in one pot at 4% formaldehyde cross-linking conditions. It doesn’t require enzyme titration, compared to other technologies, since accessible chromatin is labelled with 5mC incorporation and deter degradation by nicking enzyme, thus opening the possibility for automation. Supplementary Information The online version contains supplementary material available at 10.1186/s13072-021-00427-2.
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Affiliation(s)
| | | | - Hang Gyeong Chin
- Genome Biology Division, New England Biolabs, Inc., Ipswich, MA, 01983, USA
| | - Sriharsa Pradhan
- Genome Biology Division, New England Biolabs, Inc., Ipswich, MA, 01983, USA.
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7
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Zhao L, Xing P, Polavarapu VK, Zhao M, Valero-Martínez B, Dang Y, Maturi N, Mathot L, Neves I, Yildirim I, Swartling FJ, Sjöblom T, Uhrbom L, Chen X. FACT-seq: profiling histone modifications in formalin-fixed paraffin-embedded samples with low cell numbers. Nucleic Acids Res 2021; 49:e125. [PMID: 34534335 PMCID: PMC8643707 DOI: 10.1093/nar/gkab813] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 08/16/2021] [Accepted: 09/06/2021] [Indexed: 01/05/2023] Open
Abstract
The majority of biopsies in both basic research and translational cancer studies are preserved in the format of archived formalin-fixed paraffin-embedded (FFPE) samples. Profiling histone modifications in archived FFPE tissues is critically important to understand gene regulation in human disease. The required input for current genome-wide histone modification profiling studies from FFPE samples is either 10-20 tissue sections or whole tissue blocks, which prevents better resolved analyses. But it is desirable to consume a minimal amount of FFPE tissue sections in the analysis as clinical tissues of interest are limited. Here, we present FFPE tissue with antibody-guided chromatin tagmentation with sequencing (FACT-seq), the first highly sensitive method to efficiently profile histone modifications in FFPE tissues by combining a novel fusion protein of hyperactive Tn5 transposase and protein A (T7-pA-Tn5) transposition and T7 in vitro transcription. FACT-seq generates high-quality chromatin profiles from different histone modifications with low number of FFPE nuclei. We proved a very small piece of FFPE tissue section containing ∼4000 nuclei is sufficient to decode H3K27ac modifications with FACT-seq. H3K27ac FACT-seq revealed disease-specific super enhancers in the archived FFPE human colorectal and human glioblastoma cancer tissue. In summary, FACT-seq allows decoding the histone modifications in archival FFPE tissues with high sensitivity and help researchers to better understand epigenetic regulation in cancer and human disease.
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Affiliation(s)
- Linxuan Zhao
- Department of Immunology, Genetics and Pathology, Uppsala University, 75108 Uppsala, Sweden
| | - Pengwei Xing
- Department of Immunology, Genetics and Pathology, Uppsala University, 75108 Uppsala, Sweden
| | | | - Miao Zhao
- Department of Immunology, Genetics and Pathology, Uppsala University, 75108 Uppsala, Sweden
| | - Blanca Valero-Martínez
- Department of Immunology, Genetics and Pathology, Uppsala University, 75108 Uppsala, Sweden
| | - Yonglong Dang
- Department of Immunology, Genetics and Pathology, Uppsala University, 75108 Uppsala, Sweden
| | - Nagaprathyusha Maturi
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Rudbeck Laboratory, SE-75185 Uppsala, Sweden
| | - Lucy Mathot
- Department of Immunology, Genetics and Pathology, Uppsala University, 75108 Uppsala, Sweden
| | - Inês Neves
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Rudbeck Laboratory, SE-75185 Uppsala, Sweden
| | - Irem Yildirim
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Rudbeck Laboratory, SE-75185 Uppsala, Sweden
| | | | - Tobias Sjöblom
- Department of Immunology, Genetics and Pathology, Uppsala University, 75108 Uppsala, Sweden
| | - Lene Uhrbom
- Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Rudbeck Laboratory, SE-75185 Uppsala, Sweden
| | - Xingqi Chen
- Department of Immunology, Genetics and Pathology, Uppsala University, 75108 Uppsala, Sweden
- Beijer Laboratories, Uppsala University, Uppsala, Sweden
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8
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Marcel SS, Quimby AL, Noel MP, Jaimes OC, Mehrab-Mohseni M, Ashur SA, Velasco B, Tsuruta JK, Kasoji SK, Santos CM, Dayton PA, Parker JS, Davis IJ, Pattenden SG. Genome-wide cancer-specific chromatin accessibility patterns derived from archival processed xenograft tumors. Genome Res 2021; 31:2327-2339. [PMID: 34815311 PMCID: PMC8647830 DOI: 10.1101/gr.275219.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 10/22/2021] [Indexed: 01/01/2023]
Abstract
Chromatin accessibility states that influence gene expression and other nuclear processes can be altered in disease. The constellation of transcription factors and chromatin regulatory complexes in cells results in characteristic patterns of chromatin accessibility. The study of these patterns in tissues has been limited because existing chromatin accessibility assays are ineffective for archival formalin-fixed, paraffin-embedded (FFPE) tissues. We have developed a method to efficiently extract intact chromatin from archival tissue via enhanced cavitation with a nanodroplet reagent consisting of a lipid shell with a liquid perfluorocarbon core. Inclusion of nanodroplets during the extraction of chromatin from FFPE tissues enhances the recovery of intact accessible and nucleosome-bound chromatin. We show that the addition of nanodroplets to the chromatin accessibility assay formaldehyde-assisted isolation of regulatory elements (FAIRE), does not affect the accessible chromatin signal. Applying the technique to FFPE human tumor xenografts, we identified tumor-relevant regions of accessible chromatin shared with those identified in primary tumors. Further, we deconvoluted non-tumor signal to identify cellular components of the tumor microenvironment. Incorporation of this method of enhanced cavitation into FAIRE offers the potential for extending chromatin accessibility to clinical diagnosis and personalized medicine, while also enabling the exploration of gene regulatory mechanisms in archival samples.
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Affiliation(s)
- Shelsa S Marcel
- Curriculum in Bioinformatics and Computational Biology, Curriculum in Genetics and Molecular Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514, USA
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Austin L Quimby
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Melodie P Noel
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Oscar C Jaimes
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Marjan Mehrab-Mohseni
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, North Carolina 27599, USA
| | - Suud A Ashur
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Brian Velasco
- Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, North Carolina 27599, USA
| | - James K Tsuruta
- Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, North Carolina 27599, USA
| | - Sandeep K Kasoji
- Triangle Biotechnology, Incorporated, Chapel Hill, North Carolina 27517, USA
| | - Charlene M Santos
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Paul A Dayton
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, North Carolina 27599, USA
| | - Joel S Parker
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Genetics, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Ian J Davis
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Genetics, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Division of Pediatric Hematology-Oncology, Department of Pediatrics, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Samantha G Pattenden
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Genetics, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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9
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Slot E, Boers R, Boers J, van IJcken WFJ, Tibboel D, Gribnau J, Rottier R, de Klein A. Genome wide DNA methylation analysis of alveolar capillary dysplasia lung tissue reveals aberrant methylation of genes involved in development including the FOXF1 locus. Clin Epigenetics 2021; 13:148. [PMID: 34325731 PMCID: PMC8323302 DOI: 10.1186/s13148-021-01134-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 07/14/2021] [Indexed: 12/11/2022] Open
Abstract
Background Alveolar capillary dysplasia with or without misalignment of the pulmonary veins (ACD/MPV) is a lethal congenital lung disorder associated with a variety of heterozygous genomic alterations in the FOXF1 gene or its 60 kb enhancer. Cases without a genomic alteration in the FOXF1 locus have been described as well. The mechanisms responsible for FOXF1 haploinsufficiency and the cause of ACD/MPV in patients without a genomic FOXF1 variant are poorly understood, complicating the search for potential therapeutic targets for ACD/MPV. To investigate the contribution of aberrant DNA methylation, genome wide methylation patterns of ACD/MPV lung tissues were compared with methylation patterns of control lung tissues using the recently developed technique Methylated DNA sequencing (MeD-seq).
Results Eight ACD/MPV lung tissue samples and three control samples were sequenced and their mutual comparison resulted in identification of 319 differentially methylated regions (DMRs) genome wide, involving 115 protein coding genes. The potentially upregulated genes were significantly enriched in developmental signalling pathways, whereas potentially downregulated genes were mainly enriched in O-linked glycosylation. In patients with a large maternal deletion encompassing the 60 kb FOXF1 enhancer, DNA methylation patterns in this FOXF1 enhancer were not significantly different compared to controls. However, two hypermethylated regions were detected in the 60 kb FOXF1 enhancer of patients harbouring a FOXF1 point mutation. Lastly, a large hypermethylated region overlapping the first FOXF1 exon was found in one of the ACD/MPV patients without a known pathogenic FOXF1 variation.
Conclusion This is the first study providing genome wide methylation data on lung tissue of ACD/MPV patients. DNA methylation analyses in the FOXF1 locus excludes maternal imprinting of the 60 kb FOXF1 enhancer. Hypermethylation at the 60 kb FOXF1 enhancer might contribute to FOXF1 haploinsufficiency caused by heterozygous mutations in the FOXF1 coding region. Interestingly, DNA methylation analyses of patients without a genomic FOXF1 variant suggest that abnormal hypermethylation of exon 1 might play a role in some ACD/MPV in patients. Supplementary Information The online version contains supplementary material available at 10.1186/s13148-021-01134-1.
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Affiliation(s)
- Evelien Slot
- Department of Paediatric Surgery, Erasmus MC - Sophia Children's Hospital Rotterdam, Rotterdam, Netherlands.,Department of Clinical Genetics, Rm Ee2089, Erasmus MC Rotterdam, Wytemaweg 80, 3015 CN, Rotterdam, Netherlands
| | - Ruben Boers
- Department of Developmental Biology, Oncode Institute, Erasmus MC Rotterdam, Rotterdam, Netherlands
| | - Joachim Boers
- Department of Developmental Biology, Oncode Institute, Erasmus MC Rotterdam, Rotterdam, Netherlands
| | - Wilfred F J van IJcken
- Center for Biomics, Erasmus University Medical Center, Erasmus MC, Rotterdam, Netherlands.,Department of Cell Biology, Erasmus University Medical Center, Erasmus MC, Rotterdam, Netherlands
| | - Dick Tibboel
- Department of Paediatric Surgery, Erasmus MC - Sophia Children's Hospital Rotterdam, Rotterdam, Netherlands
| | - Joost Gribnau
- Department of Developmental Biology, Oncode Institute, Erasmus MC Rotterdam, Rotterdam, Netherlands
| | - Robbert Rottier
- Department of Paediatric Surgery, Erasmus MC - Sophia Children's Hospital Rotterdam, Rotterdam, Netherlands.,Department of Cell Biology, Erasmus University Medical Center, Erasmus MC, Rotterdam, Netherlands
| | - Annelies de Klein
- Department of Clinical Genetics, Rm Ee2089, Erasmus MC Rotterdam, Wytemaweg 80, 3015 CN, Rotterdam, Netherlands.
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10
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Polavarapu VK, Xing P, Zhang H, Zhao M, Mathot L, Zhao L, Rosen G, Swartling FJ, Sjöblom T, Chen X. Profiling chromatin accessibility in formalin-fixed paraffin-embedded samples. Genome Res 2021; 32:150-161. [PMID: 34261731 PMCID: PMC8744681 DOI: 10.1101/gr.275269.121] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 07/08/2021] [Indexed: 11/25/2022]
Abstract
Archived formalin-fixed paraffin-embedded (FFPE) samples are the global standard format for preservation of the majority of biopsies in both basic research and translational cancer studies, and profiling chromatin accessibility in the archived FFPE tissues is fundamental to understanding gene regulation. Accurate mapping of chromatin accessibility from FFPE specimens is challenging because of the high degree of DNA damage. Here, we first showed that standard ATAC-seq can be applied to purified FFPE nuclei but yields lower library complexity and a smaller proportion of long DNA fragments. We then present FFPE-ATAC, the first highly sensitive method for decoding chromatin accessibility in FFPE tissues that combines Tn5-mediated transposition and T7 in vitro transcription. The FFPE-ATAC generates high-quality chromatin accessibility profiles with 500 nuclei from a single FFPE tissue section, enables the dissection of chromatin profiles from the regions of interest with the aid of hematoxylin and eosin (H&E) staining, and reveals disease-associated chromatin regulation from the human colorectal cancer FFPE tissue archived for more than 10 years. In summary, the approach allows decoding of the chromatin states that regulate gene expression in archival FFPE tissues, thereby permitting investigators, to better understand epigenetic regulation in cancer and precision medicine.
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