1
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Wang G, Zhou Y, Yi B, Long Y, Ma B, Zhang Y. Comprehensive analysis of the prognostic value and biological function of TDG in hepatocellular carcinoma. Cell Cycle 2023:1-18. [PMID: 37224078 DOI: 10.1080/15384101.2023.2216501] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/30/2023] [Accepted: 04/27/2023] [Indexed: 05/26/2023] Open
Abstract
Epigenetics plays an important role in the malignant progression of tumors, in which DNA methylation can alter genetic performance without altering the DNA sequence. As a key regulator demethylation, thymine-DNA glycosylase (TDG) has been reported to participate in malignant progression of multiple tumors. In this study, we demonstrate that TDG is highly expressed in hepatocellular carcinoma (HCC) and its high expression is closely related to the poor prognosis of patients. Decreasing TDG expression can significantly inhibit the malignant biological behavior of HCC cells. ABL proto-oncogene 1(ABL1) was identified as a downstream gene regulated by TDG demethylation. In addition, TDG can affect the Hippo signaling pathway through ABL1 to regulate HCC cell proliferation, apoptosis, invasion and migration. Overall, our study demonstrated that TDG reduces DNA methylation of ABL1, increases ABL1 protein expression, and affects the Hippo signaling pathway to regulate the malignant progression of HCC.
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Affiliation(s)
- Guoliang Wang
- Department of Hepatobiliary Surgery, Department of Organ Transplantation, Guizhou Provincial People's Hospital, Guiyang, Guizhou, China
| | - Yinwen Zhou
- Department of Surgery, Zunyi Medical University, Zunyi, Guizhou, China
| | - Bin Yi
- Department of Hepatobiliary Surgery, Department of Organ Transplantation, Guizhou Provincial People's Hospital, Guiyang, Guizhou, China
| | - Yanli Long
- Department of Pathology, Guizhou Provincial People's Hospital, Guiyang, Guizhou, China
| | - Bo Ma
- Department of Hepatobiliary Surgery, Department of Organ Transplantation, Guizhou Provincial People's Hospital, Guiyang, Guizhou, China
| | - Yi Zhang
- Department of Hepatobiliary Surgery, Department of Organ Transplantation, Guizhou Provincial People's Hospital, Guiyang, Guizhou, China
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2
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Yao W, Lu CJ, Zhan LW, Wu Y, Feng J, Liu RR. Enantioselective Synthesis of N-N Atropisomers by Palladium-Catalyzed C-H Functionalization of Pyrroles. Angew Chem Int Ed Engl 2023; 62:e202218871. [PMID: 36941209 DOI: 10.1002/anie.202218871] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 03/23/2023]
Abstract
The catalytic asymmetric construction of N-N atropisomeric biaryls remains a formidable challenge. Studies of them lag far behind studies of the more classical carbon-carbon biaryl atropisomers, hampering meaningful development. Herein, the first palladium-catalyzed enantioselective C-H activation of pyrroles for the synthesis of N-N atropisomers is presented. Structurally diverse indole-pyrrole atropisomers possessing a chiral N-N axis were produced with good yields and high enantioselectivities by alkenylation, alkynylation, allylation, or arylation reactions. Furthermore, the kinetic resolution of trisubstituted N-N heterobiaryls with more sterically demanding substituents was also achieved. Importantly, this versatile C-H functionalization strategy enables iterative functionalization of pyrroles with exquisite selectivity, expediting the formation of valuable, complex, N-N atropisomers.
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Affiliation(s)
- Wang Yao
- Qingdao University, College of Chemistry and Chemical Engineering, CHINA
| | - Chuan-Jun Lu
- Qingdao University, College of Chemistry and Chemical Engineering, CHINA
| | - Li-Wen Zhan
- Qingdao University, College of Chemistry and Chemical Engineering, CHINA
| | - Yi Wu
- Qingdao University, College of Chemistry and Chemical Engineering, CHINA
| | - Jia Feng
- Qingdao University, College of Chemistry and Chemical Engineering, CHINA
| | - Ren-Rong Liu
- Qingdao University, College of Chemistry and Chemical Engineering, Ningxia Road 308#, 266071, Qingdao, CHINA
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3
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Timári I, Balla S, Fehér K, Kövér KE, Szilágyi L. 77Se-Enriched Selenoglycoside Enables Significant Enhancement in NMR Spectroscopic Monitoring of Glycan-Protein Interactions. Pharmaceutics 2022; 14:201. [PMID: 35057096 PMCID: PMC8779653 DOI: 10.3390/pharmaceutics14010201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/07/2022] [Accepted: 01/10/2022] [Indexed: 12/17/2022] Open
Abstract
Detailed investigation of ligand-protein interactions is essential for better understanding of biological processes at the molecular level. Among these binding interactions, the recognition of glycans by lectins is of particular importance in several diseases, such as cancer; therefore, inhibition of glycan-lectin/galectin interactions represents a promising perspective towards developing therapeutics controlling cancer development. The recent introduction of 77Se NMR spectroscopy for monitoring the binding of a selenoglycoside to galectins prompted interest to optimize the sensitivity by increasing the 77Se content from the natural 7.63% abundance to 99%. Here, we report a convenient synthesis of 77Se-enriched selenodigalactoside (SeDG), which is a potent ligand of the medically relevant human galectin-3 protein, and proof of the expected sensitivity gain in 2D 1H, 77Se correlation NMR experiments. Our work opens perspectives for adding isotopically enriched selenoglycans for rapid monitoring of lectin-binding of selenated as well as non-selenated ligands and for ligand screening in competition experiments.
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Affiliation(s)
- István Timári
- Department of Organic Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (I.T.); (S.B.)
| | - Sára Balla
- Department of Organic Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (I.T.); (S.B.)
| | - Krisztina Fehér
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary;
- Molecular Recognition and Interaction Research Group, Hungarian Academy of Sciences, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary
| | - Katalin E. Kövér
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary;
- Molecular Recognition and Interaction Research Group, Hungarian Academy of Sciences, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary
| | - László Szilágyi
- Department of Organic Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (I.T.); (S.B.)
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4
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Liu X, Chen L, Wang T, Zhou J, Li Z, Bu G, Zhang J, Yin S, Wu D, Dou C, Xu T, He H, Zhu W, Yu L, Liu Z, Zhang X, Chen ZX, Miao YL. TDG is a pig-specific epigenetic regulator with insensitivity to H3K9 and H3K27 demethylation in nuclear transfer embryos. Stem Cell Reports 2021; 16:2674-2689. [PMID: 34678203 PMCID: PMC8581057 DOI: 10.1016/j.stemcr.2021.09.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 12/15/2022] Open
Abstract
Pig cloning by somatic cell nuclear transfer (SCNT) frequently undergoes incomplete epigenetic remodeling during the maternal-to-zygotic transition, which leads to a significant embryonic loss before implantation. Here, we generated the first genome-wide landscapes of histone methylation in pig SCNT embryos. Excessive H3K9me3 and H3K27me3, but not H3K4me3, were observed in the genomic regions with unfaithful embryonic genome activation and donor-cell-specific gene silencing. A combination of H3K9 demethylase KDM4A and GSK126, an inhibitor of H3K27me3 writer, were able to remove these epigenetic barriers and restore the global transcriptome in SCNT embryos. More importantly, thymine DNA glycosylase (TDG) was defined as a pig-specific epigenetic regulator for nuclear reprogramming, which was not reactivated by H3K9me3 and H3K27me3 removal. Both combined treatment and transient TDG overexpression promoted DNA demethylation and enhanced the blastocyst-forming rates of SCNT embryos, thus offering valuable methods to increase the cloning efficiency of genome-edited pigs for agricultural and biomedical purposes. Identification of reprogramming-resistant genes and regions in porcine SCNT embryos H3K9me3 and H3K27me3 are enriched in reprogramming-resistant genes and regions Removing H3K9me3 and H3K27me3 by KDM4A and GSK126 facilitates nuclear reprogramming Transient TDG overexpression promotes DNA demethylation and improves reprogramming
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Affiliation(s)
- Xin Liu
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Lu Chen
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Tao Wang
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Jilong Zhou
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Zhekun Li
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Guowei Bu
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Jingjing Zhang
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Shuyuan Yin
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Danya Wu
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Chengli Dou
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Tian Xu
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Hainan He
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Wei Zhu
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Longtao Yu
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Zhiting Liu
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China
| | - Xia Zhang
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Zhen-Xia Chen
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Yi-Liang Miao
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction (Huazhong Agricultural University), Ministry of Education, Wuhan 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan 430070, China.
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5
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Liu X, Xu B, Yang J, He L, Zhang Z, Cheng X, Yu H, Liu X, Jin T, Peng Y, Huang Y, Xia L, Wang Y, Wu J, Wu X, Liu S, Shan L, Yang X, Sun L, Liang J, Zhang Y, Shang Y. UHRF2 commissions the completion of DNA demethylation through allosteric activation by 5hmC and K33-linked ubiquitination of XRCC1. Mol Cell 2021; 81:2960-2974.e7. [PMID: 34111398 DOI: 10.1016/j.molcel.2021.05.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/12/2021] [Accepted: 05/15/2021] [Indexed: 12/12/2022]
Abstract
The transition of oxidized 5-methylcytosine (5mC) intermediates into the base excision repair (BER) pipeline to complete DNA demethylation remains enigmatic. We report here that UHRF2, the only paralog of UHRF1 in mammals that fails to rescue Uhrf1-/- phenotype, is physically and functionally associated with BER complex. We show that UHRF2 is allosterically activated by 5-hydroxymethylcytosine (5hmC) and acts as a ubiquitin E3 ligase to catalyze K33-linked polyubiquitination of XRCC1. This nonproteolytic action stimulates XRCC1's interaction with the ubiquitin binding domain-bearing RAD23B, leading to the incorporation of TDG into BER complex. Integrative epigenomic analysis in mouse embryonic stem cells reveals that Uhrf2-fostered TDG-RAD23B-BER complex is functionally linked to the completion of DNA demethylation at active promoters and that Uhrf2 ablation impedes DNA demethylation on latent enhancers that undergo poised-to-active transition during neuronal commitment. Together, these observations highlight an essentiality of 5hmC-switched UHRF2 E3 ligase activity in commissioning the accomplishment of active DNA demethylation.
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Affiliation(s)
- Xiaoping Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Bosen Xu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Jianguo Yang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Lin He
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Zihan Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Xiao Cheng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Huajing Yu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Xujun Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Tong Jin
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Yani Peng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Yunchao Huang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Lu Xia
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Yue Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China; Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou 311121, China; Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Jiajing Wu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Xiaodi Wu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Shumeng Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Lin Shan
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Xiaohan Yang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Luyang Sun
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Jing Liang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China
| | - Yu Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China.
| | - Yongfeng Shang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Health Science Center, Beijing 100191, China; Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou 311121, China; Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China.
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6
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Kansakar U, Jankauskas SS, Gambardella J, Santulli G. Targeting the phenotypic switch of vascular smooth muscle cells to tackle atherosclerosis. Atherosclerosis 2021; 324:117-120. [PMID: 33832772 DOI: 10.1016/j.atherosclerosis.2021.03.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 03/19/2021] [Accepted: 03/25/2021] [Indexed: 02/08/2023]
Affiliation(s)
- Urna Kansakar
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York City, 10461, NY, United States
| | - Stanislovas S Jankauskas
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York City, 10461, NY, United States; Department of Medicine (Division of Cardiology), Albert Einstein College of Medicine - Montefiore University Hospital, New York City, 10461, NY, United States
| | - Jessica Gambardella
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York City, 10461, NY, United States; Department of Medicine (Division of Cardiology), Albert Einstein College of Medicine - Montefiore University Hospital, New York City, 10461, NY, United States; Department of Advanced Biomedical Sciences, "Federico II" University, Naples, 80131, Italy
| | - Gaetano Santulli
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York City, 10461, NY, United States; Department of Medicine (Division of Cardiology), Albert Einstein College of Medicine - Montefiore University Hospital, New York City, 10461, NY, United States; Department of Advanced Biomedical Sciences, "Federico II" University, Naples, 80131, Italy; International Translational Research and Medical Education (ITME), Naples, 80100, Italy.
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7
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Abstract
5-Methylcytosine (5mC) is an epigenetic mark known to contribute to the regulation of gene expression in a wide range of biological systems. Ten Eleven Translocation (TET) dioxygenases oxidize 5mC to 5-hydroxymethylcytosine, 5-formylcytosine, and 5-carboxylcytosine in metazoans and fungi. Moreover, two recent reports imply the existence of other species of modified cytosine in unicellular alga Chlamydomonas reinhardtii and malaria parasite Plasmodium falciparum. Here we provide an overview of the spectrum of cytosine modifications and their roles in demethylation of DNA and regulation of gene expression in different eukaryotic organisms.
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Affiliation(s)
- Maria Eleftheriou
- Division of Cancer and Stem Cells, School of Medicine, Biodiscovery Institute, University of Nottingham, University Park, UK
| | - Alexey Ruzov
- Division of Cancer and Stem Cells, School of Medicine, Biodiscovery Institute, University of Nottingham, University Park, UK.
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8
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Prasad R, Yen TJ, Bellacosa A. Active DNA demethylation-The epigenetic gatekeeper of development, immunity, and cancer. Adv Genet (Hoboken) 2020; 2:e10033. [PMID: 36618446 PMCID: PMC9744510 DOI: 10.1002/ggn2.10033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/16/2020] [Accepted: 10/16/2020] [Indexed: 01/11/2023]
Abstract
DNA methylation is a critical process in the regulation of gene expression with dramatic effects in development and continually expanding roles in oncogenesis. 5-Methylcytosine was once considered to be an inherited and stably repressive epigenetic mark, which can be only removed by passive dilution during multiple rounds of DNA replication. However, in the past two decades, physiologically controlled DNA demethylation and deamination processes have been identified, thereby revealing the function of cytosine methylation as a highly regulated and complex state-not simply a static, inherited signature or binary on-off switch. Alongside these fundamental discoveries, clinical studies over the past decade have revealed the dramatic consequences of aberrant DNA demethylation. In this review we discuss DNA demethylation and deamination in the context of 5-methylcytosine as critical processes for physiological and physiopathological transitions within three states-development, immune maturation, and oncogenic transformation; and we describe the expanding role of DNA demethylating drugs as therapeutic agents in cancer.
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Affiliation(s)
- Rahul Prasad
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer CenterPhiladelphiaPennsylvaniaUSA
| | - Timothy J. Yen
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer CenterPhiladelphiaPennsylvaniaUSA
| | - Alfonso Bellacosa
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer CenterPhiladelphiaPennsylvaniaUSA
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9
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Sandoval JE, Reich NO. p53 and TDG are dominant in regulating the activity of the human de novo DNA methyltransferase DNMT3A on nucleosomes. J Biol Chem 2020; 296:100058. [PMID: 33172892 PMCID: PMC7948466 DOI: 10.1074/jbc.ra120.016125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 11/03/2020] [Accepted: 11/10/2020] [Indexed: 11/07/2022] Open
Abstract
DNA methylation and histone tail modifications are interrelated mechanisms involved in a wide range of biological processes, and disruption of this crosstalk is linked to diseases such as acute myeloid leukemia. In addition, DNA methyltransferase 3A (DNMT3A) activity is modulated by several regulatory proteins, including p53 and thymine DNA glycosylase (TDG). However, the relative role of histone tails and regulatory proteins in the simultaneous coordination of DNMT3A activity remains obscure. We observed that DNMT3A binds H3 tails and p53 or TDG at distinct allosteric sites to form DNMT3A–H3 tail-p53 or –TDG multiprotein complexes. Functional characterization of DNMT3A–H3 tail-p53 or –TDG complexes on human-derived synthetic histone H3 tails, mononucleosomes, or polynucleosomes shows p53 and TDG play dominant roles in the modulation of DNMT3A activity. Intriguingly, this dominance occurs even when DNMT3A is actively methylating nucleosome substrates. The activity of histone modifiers is influenced by their ability to sense modifications on histone tails within the same nucleosome or histone tails on neighboring nucleosomes. In contrast, we show here that DNMT3A acts on DNA within a single nucleosome, on nucleosomal DNA within adjacent nucleosomes, and DNA not associated with the DNMT3A–nucleosome complex. Our findings have direct bearing on how the histone code drives changes in DNA methylation and highlight the complex interplay between histone tails, epigenetic enzymes, and modulators of enzymatic activity.
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Affiliation(s)
- Jonathan E Sandoval
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California, USA
| | - Norbert O Reich
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California, USA.
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10
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Abstract
Mechanistic and functional studies by gene disruption or editing approaches often suffer from confounding effects like compensatory cellular adaptations generated by clonal selection. These issues become particularly relevant when studying factors directly involved in genetic or epigenetic maintenance. To provide a genetic tool for functional and mechanistic investigation of DNA-repair mediated active DNA demethylation, we generated experimental models in mice and murine embryonic stem cells (ESCs) based on a minigene of the thymine-DNA glycosylase (TDG). The loxP-flanked miniTdg is rapidly and reliably excised in mice and ESCs by tamoxifen-induced Cre activation, depleting TDG to undetectable levels within 24 hours. We describe the functionality of the engineered miniTdg in mouse and ESCs (TDGiKO ESCs) and validate the pluripotency and differentiation potential of TDGiKO ESCs as well as the phenotype of induced TDG depletion. The controlled and rapid depletion of TDG allows for a precise manipulation at any point in time of multistep experimental procedures as presented here for neuronal differentiation in vitro. Thus, we provide a tested and well-controlled genetic tool for the functional and mechanistic investigation of TDG in active DNA (de)methylation and/or DNA repair with minimal interference from adaptive effects and clonal selection.
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Affiliation(s)
- Simon D Schwarz
- Department of Biomedicine, University of Basel, Basel, 4058, Switzerland
| | - Eliane Grundbacher
- Department of Biomedicine, University of Basel, Basel, 4058, Switzerland
| | - Alexandra M Hrovat
- Department of Biomedicine, University of Basel, Basel, 4058, Switzerland
| | - Jianming Xu
- Department of Biomedicine, University of Basel, Basel, 4058, Switzerland
| | - Anna Kuśnierczyk
- Proteomics and Modomics Experimental Core Facility (PROMEC), Norwegian University of Science and Technology, Trondheim, 7491, Norway
| | - Cathrine B Vågbø
- Proteomics and Modomics Experimental Core Facility (PROMEC), Norwegian University of Science and Technology, Trondheim, 7491, Norway
| | - Primo Schär
- Department of Biomedicine, University of Basel, Basel, 4058, Switzerland
| | - David Schuermann
- Department of Biomedicine, University of Basel, Basel, 4058, Switzerland
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11
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Abstract
Mechanistic and functional studies by gene disruption or editing approaches often suffer from confounding effects like compensatory cellular adaptations generated by clonal selection. These issues become particularly relevant when studying factors directly involved in genetic or epigenetic maintenance. To provide a genetic tool for functional and mechanistic investigation of DNA-repair mediated active DNA demethylation, we generated experimental models in mice and murine embryonic stem cells (ESCs) based on a minigene of the thymine-DNA glycosylase (TDG). The loxP-flanked miniTdg is rapidly and reliably excised in mice and ESCs by tamoxifen-induced Cre activation, depleting TDG to undetectable levels within 24 hours. We describe the functionality of the engineered miniTdg in mouse and ESCs (TDGiKO ESCs) and validate the pluripotency and differentiation potential of TDGiKO ESCs as well as the phenotype of induced TDG depletion. The controlled and rapid depletion of TDG allows for a precise manipulation at any point in time of multistep experimental procedures as presented here for neuronal differentiation in vitro. Thus, we provide a tested and well-controlled genetic tool for the functional and mechanistic investigation of TDG in active DNA (de)methylation and/or DNA repair with minimal interference from adaptive effects and clonal selection.
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Affiliation(s)
- Simon D. Schwarz
- Department of Biomedicine, University of Basel, Basel, 4058, Switzerland
| | - Eliane Grundbacher
- Department of Biomedicine, University of Basel, Basel, 4058, Switzerland
| | | | - Jianming Xu
- Department of Biomedicine, University of Basel, Basel, 4058, Switzerland
| | - Anna Kuśnierczyk
- Proteomics and Modomics Experimental Core Facility (PROMEC), Norwegian University of Science and Technology, Trondheim, 7491, Norway
| | - Cathrine B. Vågbø
- Proteomics and Modomics Experimental Core Facility (PROMEC), Norwegian University of Science and Technology, Trondheim, 7491, Norway
| | - Primo Schär
- Department of Biomedicine, University of Basel, Basel, 4058, Switzerland
| | - David Schuermann
- Department of Biomedicine, University of Basel, Basel, 4058, Switzerland
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12
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Zhou W, Zhang L, Chen P, Li S, Cheng Y. Thymine DNA glycosylase-regulated TAZ promotes radioresistance by targeting nonhomologous end joining and tumor progression in esophageal cancer. Cancer Sci 2020; 111:3613-3625. [PMID: 32808385 PMCID: PMC7541017 DOI: 10.1111/cas.14622] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 08/12/2020] [Accepted: 08/14/2020] [Indexed: 12/16/2022] Open
Abstract
Radiation resistance is a major cause of esophageal cancer relapse or metastasis. Transcriptional coactivator with PDZ binding domain (TAZ) is a final effector of the Hippo signaling pathway and plays critical roles in several types of cancer, but how it participates in the progression and radiation resistance of esophageal cancer remains unclear. Here, we revealed that TAZ was the strongest prognostic factor among Hippo pathway members. Overexpression of TAZ predicted poor outcome and adverse pathological features. In cell and animal models, TAZ facilitated cell proliferation, motility, and radiation resistance. Additionally, TAZ promoted expression of nonhomologous end joining (NHEJ)‐related genes, which are the main contributors to repair irradiation‐induced DNA breaks and result in radiation resistance. Amplification of the TAZ gene occurred in 2.5%‐3.2% of esophageal cancers. In addition, the CpG islands of the TAZ gene were demethylated in esophageal cancer under thymine DNA glycosylase (TDG) regulation. Knockdown of TDG inhibited cell growth, motility, and radiation resistance, which were overridden by TAZ overexpression. Collectively, these findings suggest that the TDG/TAZ/NHEJ axis is a critical player in esophageal cancer progression and radiation resistance, as well as a potential target for radiotherapy.
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Affiliation(s)
- Wei Zhou
- Department of Radiation Oncology, Cheeloo College of Medicine, Qilu Hospital, Shandong University, Jinan, China
| | - Lin Zhang
- Department of Radiation Oncology, Cheeloo College of Medicine, Qilu Hospital, Shandong University, Jinan, China
| | - Pengxiang Chen
- Department of Radiation Oncology, Cheeloo College of Medicine, Qilu Hospital, Shandong University, Jinan, China
| | - Song Li
- Department of Medical Oncology, Cheeloo College of Medicine, Qilu Hospital, Shandong University, Jinan, China
| | - Yufeng Cheng
- Department of Radiation Oncology, Cheeloo College of Medicine, Qilu Hospital, Shandong University, Jinan, China
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13
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Yan JB, Lai CC, Jhu JW, Gongol B, Marin TL, Lin SC, Chiu HY, Yen CJ, Wang LY, Peng IC. Insulin and Metformin Control Cell Proliferation by Regulating TDG-Mediated DNA Demethylation in Liver and Breast Cancer Cells. Mol Ther Oncolytics 2020; 18:282-294. [PMID: 32728616 PMCID: PMC7378318 DOI: 10.1016/j.omto.2020.06.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 06/19/2020] [Indexed: 02/06/2023]
Abstract
Type 2 diabetes mellitus (T2DM) is a frequent comorbidity of cancer. Hyperinsulinemia secondary to T2DM promotes cancer progression, whereas antidiabetic agents, such as metformin, have anticancer effects. However, the detailed mechanism for insulin and metformin-regulated cancer cell proliferation remains unclear. This study identified a mechanism by which insulin upregulated the expression of c-Myc, sterol regulatory element-binding protein 1 (SREBP1), and acetyl-coenzyme A (CoA) carboxylase 1 (ACC1), which are important regulators of lipogenesis and cell proliferation. Thymine DNA glycosylase (TDG), a DNA demethylase, was transactivated by c-Myc upon insulin treatment, thereby decreasing 5-carboxylcytosine (5caC) abundance in the SREBP1 promoter. On the other hand, metformin-activated AMP-activated protein kinase (AMPK) increased DNA methyltransferase 3A (DNMT3A) activity to increase 5-methylcytosine (5mC) abundance in the TDG promoter. This resulted in decreased TDG expression and enhanced 5caC abundance in the SREBP1 promoter. These findings demonstrate that c-Myc activates, whereas AMPK inhibits, TDG-mediated DNA demethylation of the SREBP1 promoter in insulin-promoted and metformin-suppressed cancer progression, respectively. This study indicates that TDG is an epigenetic-based therapeutic target for cancers associated with T2DM.
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Affiliation(s)
- Jia-Bao Yan
- Department of Life Sciences, National Cheng Kung University, Tainan City 701, Taiwan
| | - Chien-Cheng Lai
- Department of Life Sciences, National Cheng Kung University, Tainan City 701, Taiwan
| | - Jin-Wei Jhu
- Department of Life Sciences, National Cheng Kung University, Tainan City 701, Taiwan
| | - Brendan Gongol
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Traci L Marin
- Department of Health Sciences, Victor Valley College, Victorville, CA 92395, USA
| | - Shih-Chieh Lin
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan City 701, Taiwan
| | - Hsiang-Yi Chiu
- Department of Life Sciences, National Cheng Kung University, Tainan City 701, Taiwan
| | - Chia-Jui Yen
- Division of Hematology and Oncology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan City 701, Taiwan
| | - Liang-Yi Wang
- Department of Public Health, National Cheng Kung University, Tainan City 701, Taiwan
| | - I-Chen Peng
- Department of Life Sciences, National Cheng Kung University, Tainan City 701, Taiwan
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14
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Feng C, Zhao J, Ji F, Su L, Chen Y, Jiao J. TCF20 dysfunction leads to cortical neurogenesis defects and autistic-like behaviors in mice. EMBO Rep 2020; 21:e49239. [PMID: 32510763 DOI: 10.15252/embr.201949239] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 12/12/2022] Open
Abstract
Recently, de novo mutations of transcription factor 20 (TCF20) were found in patients with autism by large-scale exome sequencing. However, how TCF20 modulates brain development and whether its dysfunction causes ASD remain unclear. Here, we show that TCF20 deficits impair neurogenesis in mouse. TCF20 deletion significantly reduces the number of neurons, which leads to abnormal brain functions. Furthermore, transcriptome analysis and ChIP-qPCR reveal that the DNA demethylation factor TDG is a downstream target gene of TCF20. As a nonspecific DNA demethylation factor, TDG potentially affects many genes. Combined TDG ChIP-seq and GO analysis of TCF20 RNA-Seq identifies T-cell factor 4 (TCF-4) as a common target. TDG controls the DNA methylation level in the promoter area of TCF-4, affecting TCF-4 expression and modulating neural differentiation. Overexpression of TDG or TCF-4 rescues the deficient neurogenesis of TCF20 knockdown brains. Together, our data reveal that TCF20 is essential for neurogenesis and we suggest that defects in neurogenesis caused by TCF20 loss are associated with ASD.
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Affiliation(s)
- Chao Feng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China.,Sino-Danish College at University of Chinese Academy of Sciences, Beijing, China
| | - Jinyue Zhao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Fen Ji
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Libo Su
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yihui Chen
- Department of Ophthalmology, Yangpu Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jianwei Jiao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China.,Innovation Academy for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
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15
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Han D, Schomacher L, Schüle KM, Mallick M, Musheev MU, Karaulanov E, Krebs L, von Seggern A, Niehrs C. NEIL1 and NEIL2 DNA glycosylases protect neural crest development against mitochondrial oxidative stress. eLife 2019; 8:49044. [PMID: 31566562 PMCID: PMC6768664 DOI: 10.7554/elife.49044] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 09/12/2019] [Indexed: 12/11/2022] Open
Abstract
Base excision repair (BER) functions not only in the maintenance of genomic integrity but also in active DNA demethylation and epigenetic gene regulation. This dual role raises the question if phenotypic abnormalities resulting from deficiency of BER factors are due to DNA damage or impaired DNA demethylation. Here we investigate the bifunctional DNA glycosylases/lyases NEIL1 and NEIL2, which act in repair of oxidative lesions and in epigenetic demethylation. Neil-deficiency in Xenopus embryos and differentiating mouse embryonic stem cells (mESCs) leads to a surprisingly restricted defect in cranial neural crest cell (cNCC) development. Neil-deficiency elicits an oxidative stress-induced TP53-dependent DNA damage response, which impairs early cNCC specification. Epistasis experiments with Tdg-deficient mESCs show no involvement of epigenetic DNA demethylation. Instead, Neil-deficiency results in oxidative damage specific to mitochondrial DNA, which triggers a TP53-mediated intrinsic apoptosis. Thus, NEIL1 and NEIL2 DNA glycosylases protect mitochondrial DNA against oxidative damage during neural crest differentiation. The face of animals with a backbone is formed in great part by a group of cells called cranial neural crest cells. When too few of these cells are made, the skull and the face can become deformed. For example, the jaw- or cheekbones can be underdeveloped or there may be defects in the eyes or ears. These types of abnormalities are among the most common birth defects known in humans. NEIL1 and NEIL2 are mouse proteins with two roles. On the one hand, they help protect DNA from damage by acting as so-called ‘base excision repair enzymes’, meaning they remove damaged building blocks of DNA. On the other hand, they help remove a chemical group known as a methyl from DNA building blocks in a process called demethylation, which is involved both in development and disease. Previous research by Schomacher et al. in 2016 showed that, in frogs, the absence of a similar protein called Neil2, leads to deformities of the face and skull. Han et al. – who include some of the researchers involved in the 2016 study – have now used frog embryos and mouse embryonic stem cells to examine the role of the NEIL proteins in cranial neural crest cells. Stem cells can become any type of cell in the body, but when NEIL1 and NEIL2 are missing, these cells lose the ability to become cranial neural crest cells. To determine whether the effects of removing NEIL1 and NEIL2 were due to their role in DNA damage repair or demethylation, Han et al. removed two proteins, each involved in one of the two processes. Removing APEX1, which is involved in DNA damage repair, had similar effects to the removal of NEIL1 and NEIL2, while removing TDG, which only works in demethylation, did not. This indicates that NEIL1 and NEIL2’s role in DNA damage repair is likely necessary for stem cells to become cranial neural crest cells. Although NEIL1 and NEIL2 are part of the DNA repair machinery, Han et al. showed that when stem cells turn into cranial neural crest cells, these proteins are not protecting the cell’s genomic DNA. Instead, they are active in the mitochondria, the compartments of the cell responsible for producing energy, which have their own DNA. Mitochondria use oxygen to produce energy, but by-products of these reactions damage mitochondrial DNA, explaining why mitochondria need NEIL1 and NEIL2. These results suggest that antioxidants, which are molecules that protect the cells from the damaging oxygen derivatives, may help prevent deformities in the face and skull. This theory could be tested using mice that do not produce proteins involved in base excision repair, which could be derived from the cells lacking NEIL1 and NEIL2.
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Affiliation(s)
- Dandan Han
- Institute of Molecular Biology (IMB), Mainz, Germany
| | | | | | | | | | | | - Laura Krebs
- Institute of Molecular Biology (IMB), Mainz, Germany
| | | | - Christof Niehrs
- Institute of Molecular Biology (IMB), Mainz, Germany.,Division of Molecular Embryology, DKFZ-ZMBH Alliance, Heidelberg, Germany
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16
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Cheng T, Xu M, Qin B, Wu J, Tu Y, Kang L, Wang Y, Guan H. lncRNA H19 contributes to oxidative damage repair in the early age-related cataract by regulating miR-29a/ TDG axis. J Cell Mol Med 2019; 23:6131-6139. [PMID: 31282110 PMCID: PMC6714223 DOI: 10.1111/jcmm.14489] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/19/2019] [Accepted: 05/23/2019] [Indexed: 11/30/2022] Open
Abstract
Age‐related cataract (ARC) is caused by the exposure of the lens to UVB which promotes oxidative damage and cell death. This study aimed to explore the role of lncRNA H19 in oxidative damage repair in early ARC. lncRNAs sequencing technique was used to identify different lncRNAs in the lens of early ARC patients. Human lens epithelial cells (HLECs) were exposed to ultraviolet irradiation; and 8‐OHdG ELISA, Cell counting kit 8 (CCK8), EDU, flow cytometry and TUNEL assays were used to detect DNA damage, cell viability, proliferation and apoptosis. Luciferase assay was used to examine the interaction among H19, miR‐29a and thymine DNA glycosylase (TDG) 3'UTR. We found that lncRNA H19 and TDG were highly expressed while miR‐29a was down‐regulated in the three types of early ARC and HLECs exposed to ultraviolet irradiation, compared to respective controls. lncRNA H19 knockdown aggravated oxidative damage, reduced cell viability and proliferation, and promoted apoptosis in HLECs, while lncRNA H19 overexpression led to opposite effects in HLECs. Mechanistically, miR‐29a bound TDG 3'UTR to repress TDG expression. lncRNA H19 up‐regulated the expression of TDG by repressing miR‐29a because it acted as ceRNA through sponging miR‐29a. In conclusion, the interaction among lncRNA H19, miR‐29a and TDG is involved in early ARC. lncRNA H19 could be a useful marker of early ARC and oxidative damage repair pathway of lncRNA H19/miR‐29a/TDG may be a promising target for the treatment of ARC.
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Affiliation(s)
- Tianyu Cheng
- The Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, China.,Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Mudong Xu
- The Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, China
| | - Bai Qin
- The Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, China
| | - Jian Wu
- The Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, China
| | - Yuanyuan Tu
- The Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, China
| | - Lihua Kang
- The Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, China
| | - Yong Wang
- The Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, China
| | - Huaijin Guan
- The Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, China
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17
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Abstract
Methylase-assisted bisulfite sequencing (MAB-seq) is a derivatization technique to evaluate the presence of 5-formylcytosine (5-fC) and 5-carboxylcytosine (5-caC) at base-pair resolution. Although MAB-seq was originally designed to study these metabolites under steady-state conditions, we have developed an alternative protocol to evaluate the dynamics of 5-fC/5-caC accumulation in response to agonists, such as all-trans retinoic acid (ATRA). In addition, this protocol utilizes a lower quantity of the M.SssI enzyme without compromising methylation efficiency and requires less bench time. Herein, we describe the use of MAB-seq assay to evaluate the generation of 5-fC/5-caC in response to ATRA in mouse embryonic fibroblasts, using the hypermethylated in cancer 1 (Hic1) locus as a model system.
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Affiliation(s)
- Haider M Hassan
- Department of Biochemistry, Western University, London, ON, Canada
- Department of Oncology, The London Regional Cancer Program and the Lawson Health Research Institute, London, ON, Canada
| | - T Michael Underhill
- Department of Cellular and Physiological Sciences and the Biomedical Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Joseph Torchia
- Department of Biochemistry, Western University, London, ON, Canada.
- Department of Oncology, The London Regional Cancer Program and the Lawson Health Research Institute, London, ON, Canada.
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18
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Valentini E, Zampieri M, Malavolta M, Bacalini MG, Calabrese R, Guastafierro T, Reale A, Franceschi C, Hervonen A, Koller B, Bernhardt J, Slagboom PE, Toussaint O, Sikora E, Gonos ES, Breusing N, Grune T, Jansen E, Dollé MET, Moreno-Villanueva M, Sindlinger T, Bürkle A, Ciccarone F, Caiafa P. Analysis of the machinery and intermediates of the 5hmC-mediated DNA demethylation pathway in aging on samples from the MARK-AGE Study. Aging (Albany NY) 2017; 8:1896-1922. [PMID: 27587280 PMCID: PMC5076444 DOI: 10.18632/aging.101022] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 08/15/2016] [Indexed: 12/22/2022]
Abstract
Gradual changes in the DNA methylation landscape occur throughout aging virtually in all human tissues. A widespread reduction of 5-methylcytosine (5mC), associated with highly reproducible site-specific hypermethylation, characterizes the genome in aging. Therefore, an equilibrium seems to exist between general and directional deregulating events concerning DNA methylation controllers, which may underpin the age-related epigenetic changes. In this context, 5mC-hydroxylases (TET enzymes) are new potential players. In fact, TETs catalyze the stepwise oxidation of 5mC to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC), driving the DNA demethylation process based on thymine DNA glycosylase (TDG)-mediated DNA repair pathway. The present paper reports the expression of DNA hydroxymethylation components, the levels of 5hmC and of its derivatives in peripheral blood mononuclear cells of age-stratified donors recruited in several European countries in the context of the EU Project 'MARK-AGE'. The results provide evidence for an age-related decline of TET1, TET3 and TDG gene expression along with a decrease of 5hmC and an accumulation of 5caC. These associations were independent of confounding variables, including recruitment center, gender and leukocyte composition. The observed impairment of 5hmC-mediated DNA demethylation pathway in blood cells may lead to aberrant transcriptional programs in the elderly.
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Affiliation(s)
- Elisabetta Valentini
- Department of Cellular Biotechnologies and Hematology, Faculty of Pharmacy and Medicine, Sapienza University of Rome, Rome 00161, Italy.,Pasteur Institute-Fondazione Cenci Bolognetti, Rome 00161, Italy
| | - Michele Zampieri
- Department of Cellular Biotechnologies and Hematology, Faculty of Pharmacy and Medicine, Sapienza University of Rome, Rome 00161, Italy.,Pasteur Institute-Fondazione Cenci Bolognetti, Rome 00161, Italy
| | - Marco Malavolta
- National Institute of Health and Science on Aging (INRCA), Nutrition and Ageing Centre, Scientific and Technological Research Area, 60100 Ancona, Italy
| | - Maria Giulia Bacalini
- Department of Experimental, Diagnostic and Specialty Medicine, Alma Mater Studiorum-University of Bologna, Bologna 40126, Italy.,CIG-Interdepartmental Center "L. Galvani", Alma Mater Studiorum, University of Bologna, 40126 Bologna, Italy
| | - Roberta Calabrese
- Department of Cellular Biotechnologies and Hematology, Faculty of Pharmacy and Medicine, Sapienza University of Rome, Rome 00161, Italy.,Pasteur Institute-Fondazione Cenci Bolognetti, Rome 00161, Italy
| | - Tiziana Guastafierro
- Department of Cellular Biotechnologies and Hematology, Faculty of Pharmacy and Medicine, Sapienza University of Rome, Rome 00161, Italy.,Pasteur Institute-Fondazione Cenci Bolognetti, Rome 00161, Italy
| | - Anna Reale
- Department of Cellular Biotechnologies and Hematology, Faculty of Pharmacy and Medicine, Sapienza University of Rome, Rome 00161, Italy
| | - Claudio Franceschi
- Department of Experimental, Diagnostic and Specialty Medicine, Alma Mater Studiorum-University of Bologna, Bologna 40126, Italy.,CIG-Interdepartmental Center "L. Galvani", Alma Mater Studiorum, University of Bologna, 40126 Bologna, Italy
| | - Antti Hervonen
- The School of Medicine, The University of Tampere, 33014 Tampere, Finland
| | - Bernhard Koller
- Department for Internal Medicine, University Teaching Hospital Hall in Tirol, Tirol, Austria
| | | | - P Eline Slagboom
- Department of Molecular Epidemiology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Olivier Toussaint
- University of Namur, Research Unit on Cellular Biology, Namur B-5000, Belgium
| | - Ewa Sikora
- Laboratory of the Molecular Bases of Ageing, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Efstathios S Gonos
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry and Biotechnology, Athens, Greece
| | - Nicolle Breusing
- Institute of Nutritional Medicine (180c), University of Hohenheim, 70599 Stuttgart, Gemany
| | - Tilman Grune
- German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany
| | - Eugène Jansen
- Centre for Health Protection, National Institute for Public Health and the Environment, 3720 BA Bilthoven, The Netherlands
| | - Martijn E T Dollé
- Centre for Health Protection, National Institute for Public Health and the Environment, 3720 BA Bilthoven, The Netherlands
| | - María Moreno-Villanueva
- Molecular Toxicology Group, Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Thilo Sindlinger
- Molecular Toxicology Group, Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Alexander Bürkle
- Molecular Toxicology Group, Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Fabio Ciccarone
- Department of Biology, University of Rome "Tor Vergata", 00133 Rome, Italy.,Shared senior authorship
| | - Paola Caiafa
- Department of Cellular Biotechnologies and Hematology, Faculty of Pharmacy and Medicine, Sapienza University of Rome, Rome 00161, Italy.,Pasteur Institute-Fondazione Cenci Bolognetti, Rome 00161, Italy.,Shared senior authorship
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19
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Xu J, Cortellino S, Tricarico R, Chang WC, Scher G, Devarajan K, Slifker M, Moore R, Bassi MR, Caretti E, Clapper M, Cooper H, Bellacosa A. Thymine DNA Glycosylase (TDG) is involved in the pathogenesis of intestinal tumors with reduced APC expression. Oncotarget 2017; 8:89988-89997. [PMID: 29163805 PMCID: PMC5685726 DOI: 10.18632/oncotarget.21219] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 08/21/2017] [Indexed: 12/22/2022] Open
Abstract
Thymine DNA Glycosylase (TDG) is a base excision repair enzyme that acts as a thymine and uracil DNA N-glycosylase on G:T and G:U mismatches, thus protecting CpG sites in the genome from mutagenesis by deamination. In addition, TDG has an epigenomic function by removing the novel cytosine derivatives 5-formylcytosine and 5-carboxylcytosine (5caC) generated by Ten-Eleven Translocation (TET) enzymes during active DNA demethylation. We and others previously reported that TDG is essential for mammalian development. However, its involvement in tumor formation is unknown. To study the role of TDG in tumorigenesis, we analyzed the effects of its inactivation in a well-characterized model of tumor predisposition, the ApcMin mouse strain. Mice bearing a conditional Tdgflox allele were crossed with Fabpl::Cre transgenic mice, in the context of the ApcMin mutation, in order to inactivate Tdg in the small intestinal and colonic epithelium. We observed an approximately 2-fold increase in the number of small intestinal adenomas in the test Tdg-mutant ApcMin mice in comparison to control genotypes (p=0.0001). This increase occurred in female mice, and is similar to the known increase in intestinal adenoma formation due to oophorectomy. In the human colorectal cancer (CRC) TCGA database, the subset of patients with TDG and APC expression in the lowest quartile exhibits an excess of female cases. We conclude that TDG inactivation plays a role in intestinal tumorigenesis initiated by mutation/underexpression of APC. Our results also indicate that TDG may be involved in sex-specific protection from CRC.
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Affiliation(s)
- Jinfei Xu
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Salvatore Cortellino
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Rossella Tricarico
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Wen-Chi Chang
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Gabrielle Scher
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Karthik Devarajan
- Department of Biostatistics, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Michael Slifker
- Department of Biostatistics, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Robert Moore
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Maria Rosaria Bassi
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Elena Caretti
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Margie Clapper
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Harry Cooper
- Department of Pathology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Alfonso Bellacosa
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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20
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Periyasamy P, Shinohara T. Age-related cataracts: Role of unfolded protein response, Ca 2+ mobilization, epigenetic DNA modifications, and loss of Nrf2/Keap1 dependent cytoprotection. Prog Retin Eye Res 2017; 60:1-19. [PMID: 28864287 DOI: 10.1016/j.preteyeres.2017.08.003] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 08/26/2017] [Accepted: 08/28/2017] [Indexed: 12/11/2022]
Abstract
Age-related cataracts are closely associated with lens chronological aging, oxidation, calcium imbalance, hydration and crystallin modifications. Accumulating evidence indicates that misfolded proteins are generated in the endoplasmic reticulum (ER) by most cataractogenic stresses. To eliminate misfolded proteins from cells before they can induce senescence, the cells activate a clean-up machinery called the ER stress/unfolded protein response (UPR). The UPR also activates the nuclear factor-erythroid-2-related factor 2 (Nrf2), a central transcriptional factor for cytoprotection against stress. Nrf2 activates nearly 600 cytoprotective target genes. However, if ER stress reaches critically high levels, the UPR activates destructive outputs to trigger programmed cell death. The UPR activates mobilization of ER-Ca2+ to the cytoplasm and results in activation of Ca2+-dependent proteases to cleave various enzymes and proteins which cause the loss of normal lens function. The UPR also enhances the overproduction of reactive oxygen species (ROS), which damage lens constituents and induce failure of the Nrf2 dependent cytoprotection. Kelch-like ECH-associated protein 1 (Keap1) is an oxygen sensor protein and regulates the levels of Nrf2 by the proteasomal degradation. A significant loss of DNA methylation in diabetic cataracts was found in the Keap1 promoter, which overexpresses the Keap1 protein. Overexpressed Keap1 significantly decreases the levels of Nrf2. Lower levels of Nrf2 induces loss of the redox balance toward to oxidative stress thereby leading to failure of lens cytoprotection. Here, this review summarizes the overall view of ER stress, increases in Ca2+ levels, protein cleavage, and loss of the well-established stress protection in somatic lens cells.
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21
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Weng YL, An R, Cassin J, Joseph J, Mi R, Wang C, Zhong C, Jin SG, Pfeifer GP, Bellacosa A, Dong X, Hoke A, He Z, Song H, Ming GL. An Intrinsic Epigenetic Barrier for Functional Axon Regeneration. Neuron 2017; 94:337-346.e6. [PMID: 28426967 PMCID: PMC6007997 DOI: 10.1016/j.neuron.2017.03.034] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 02/05/2017] [Accepted: 03/23/2017] [Indexed: 12/15/2022]
Abstract
Mature neurons in the adult peripheral nervous system can effectively switch from a dormant state with little axonal growth to robust axon regeneration upon injury. The mechanisms by which injury unlocks mature neurons' intrinsic axonal growth competence are not well understood. Here, we show that peripheral sciatic nerve lesion in adult mice leads to elevated levels of Tet3 and 5-hydroxylmethylcytosine in dorsal root ganglion (DRG) neurons. Functionally, Tet3 is required for robust axon regeneration of DRG neurons and behavioral recovery. Mechanistically, peripheral nerve injury induces DNA demethylation and upregulation of multiple regeneration-associated genes in a Tet3- and thymine DNA glycosylase-dependent fashion in DRG neurons. In addition, Pten deletion-induced axon regeneration of retinal ganglion neurons in the adult CNS is attenuated upon Tet1 knockdown. Together, our study suggests an epigenetic barrier that can be removed by active DNA demethylation to permit axon regeneration in the adult mammalian nervous system.
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Affiliation(s)
- Yi-Lan Weng
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ran An
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200040, China
| | - Jessica Cassin
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Pre-doctoral Human Genetics Training Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jessica Joseph
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ruifa Mi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Chen Wang
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Chun Zhong
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Seung-Gi Jin
- Center for Epigenetics, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Gerd P. Pfeifer
- Center for Epigenetics, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Alfonso Bellacosa
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ahmet Hoke
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Zhigang He
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Hongjun Song
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Pre-doctoral Human Genetics Training Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Guo-li Ming
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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22
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Abstract
DNA methylation plays important roles in development and disease. Yet, only recently has the dynamic nature of this epigenetic mark via oxidation and DNA repair-mediated demethylation been recognized. A major conceptual challenge to the model that DNA methylation is reversible is the risk of genomic instability, which may come with widespread DNA repair activity. Here, we focus on recent advances in mechanisms of TET-TDG mediated demethylation and cellular strategies that avoid genomic instability. We highlight the recently discovered involvement of NEIL DNA glycosylases, which cooperate with TDG in oxidative demethylation to accelerate substrate turnover and promote the organized handover of harmful repair intermediates to maintain genome stability.
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Affiliation(s)
| | - Christof Niehrs
- Institute of Molecular Biology (IMB), Mainz, Germany.,Division of Molecular Embryology, German Cancer Research Center-Zentrum für Molekulare Biologie der Universität Heidelberg (DKFZ-ZMBH) Alliance, Heidelberg, Germany
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23
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Abstract
DNA demethylation can occur passively by "dilution" of methylation marks by DNA replication, or actively and independently of DNA replication. Direct conversion of 5-methylcytosine (5mC) to cytosine (C), as originally proposed, does not occur. Instead, active DNA methylation involves oxidation of the methylated base by ten-eleven translocations (TETs), or deamination of the methylated or a nearby base by activation induced deaminase (AID). The modified nucleotide, possibly together with surrounding nucleotides, is then replaced by the BER pathway. Recent data clarify the roles and the regulation of well-known enzymes in this process. They identify base excision repair (BER) glycosylases that may cooperate with or replace thymine DNA glycosylase (TDG) in the base excision step, and suggest possible involvement of DNA damage repair pathways other than BER in active DNA demethylation. Here, we review these new developments.
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Affiliation(s)
- Matthias Bochtler
- International Institute of Molecular and Cell Biology, Warsaw, Poland.,Institute of Biochemistry and Biophysics Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Kolano
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Guo-Liang Xu
- Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
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24
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Sun J, Shen Q, Lu H, Jiang Z, Xu W, Feng L, Li L, Wang X, Cai X, Jin H. Oncogenic Ras suppresses ING4- TDG-Fas axis to promote apoptosis resistance. Oncotarget 2016; 6:41997-2007. [PMID: 26544625 PMCID: PMC4747204 DOI: 10.18632/oncotarget.6015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 10/12/2015] [Indexed: 02/07/2023] Open
Abstract
Ras is aberrantly activated in many cancers and active DNA demethylation plays a fundamental role to establish DNA methylation pattern which is of importance to cancer development. However, it was unknown whether and how Ras regulate DNA demethylation during carcinogenesis. Here we found that Ras downregulated thymine-DNA glycosylase (TDG), a DNA demethylation enzyme, by inhibiting the interaction of transcription activator ING4 with TDG promoter. TDG recruited histone lysine demethylase JMJD3 to the Fas promoter and activated its expression, thus restoring sensitivity to apoptosis. TDG suppressed in vivo tumorigenicity of xenograft pancreatic cancer. Thus, we speculate that reversing Ras-mediated ING4 inhibition to activate Fas expression is a potential therapeutic approach for Ras-driven cancers.
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Affiliation(s)
- Jie Sun
- Laboratory of Cancer Biology, Provincial Key Lab of Biotherapy in Zhejiang, Sir Runrun Shaw Hospital, Medical School of Zhejiang University, Hangzhou, China
| | - Qi Shen
- Department of Medical Oncology, Sir Runrun Shaw Hospital, Medical School of Zhejiang University, Hangzhou, China
| | - Haiqi Lu
- Department of Medical Oncology, Sir Runrun Shaw Hospital, Medical School of Zhejiang University, Hangzhou, China
| | - Zhinong Jiang
- Department of Pathology, Sir Runrun Shaw Hospital, Medical School of Zhejiang University, Hangzhou, China
| | - Wenxia Xu
- Laboratory of Cancer Biology, Provincial Key Lab of Biotherapy in Zhejiang, Sir Runrun Shaw Hospital, Medical School of Zhejiang University, Hangzhou, China
| | - Lifeng Feng
- Laboratory of Cancer Biology, Provincial Key Lab of Biotherapy in Zhejiang, Sir Runrun Shaw Hospital, Medical School of Zhejiang University, Hangzhou, China
| | - Ling Li
- Division of Hematopoietic Stem Cell and Leukemia Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Xian Wang
- Department of Medical Oncology, Sir Runrun Shaw Hospital, Medical School of Zhejiang University, Hangzhou, China
| | - Xiujun Cai
- Department of General Surgery, Sir Runrun Shaw Hospital, Medical School of Zhejiang University, Hangzhou, China
| | - Hongchuan Jin
- Laboratory of Cancer Biology, Provincial Key Lab of Biotherapy in Zhejiang, Sir Runrun Shaw Hospital, Medical School of Zhejiang University, Hangzhou, China
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25
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Abstract
Pathways that control and modulate DNA methylation patterning in mammalian cells were poorly understood for a long time, although their importance in establishing and maintaining cell type-specific gene expression was well recognized. The discovery of proteins capable of converting 5-methylcytosine (5mC) to putative substrates for DNA repair introduced a novel and exciting conceptual framework for the investigation and ultimate discovery of molecular mechanisms of DNA demethylation. Against the prevailing notion that DNA methylation is a static epigenetic mark, it turned out to be dynamic and distinct mechanisms appear to have evolved to effect global and locus-specific DNA demethylation. There is compelling evidence that DNA repair, in particular base excision repair, contributes significantly to the turnover of 5mC in cells. By actively demethylating DNA, DNA repair supports the developmental establishment as well as the maintenance of DNA methylation landscapes and gene expression patterns. Yet, while the biochemical pathways are relatively well-established and reviewed, the biological context, function and regulation of DNA repair-mediated active DNA demethylation remains uncertain. In this review, we will thus summarize and critically discuss the evidence that associates active DNA demethylation by DNA repair with specific functional contexts including the DNA methylation erasure in the early embryo, the control of pluripotency and cellular differentiation, the maintenance of cell identity, and the nuclear reprogramming.
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Affiliation(s)
- David Schuermann
- Department of Biomedicine, University of Basel, Mattenstrasse 28, CH-4058 Basel, Switzerland
| | - Alain R Weber
- Department of Biomedicine, University of Basel, Mattenstrasse 28, CH-4058 Basel, Switzerland
| | - Primo Schär
- Department of Biomedicine, University of Basel, Mattenstrasse 28, CH-4058 Basel, Switzerland.
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26
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Xu X, Watt DS, Liu C. Multifaceted roles for thymine DNA glycosylase in embryonic development and human carcinogenesis. Acta Biochim Biophys Sin (Shanghai) 2016; 48:82-9. [PMID: 26370152 DOI: 10.1093/abbs/gmv083] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 07/12/2015] [Indexed: 01/03/2023] Open
Abstract
Thymine DNA glycosylase (TDG) is a multifunctional protein that plays important roles in DNA repair, DNA demethylation, and transcriptional regulation. These diverse functions make TDG a unique enzyme in embryonic development and carcinogenesis. This review discusses the molecular function of TDG in human cancers and the previously unrecognized value of TDG as a potential target for drug therapy.
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Affiliation(s)
- Xuehe Xu
- Department of Molecular and Cellular Biochemistry, Markey Cancer Center, University of Kentucky, Lexington, KY 40536-0509, USA
| | - David S Watt
- Department of Molecular and Cellular Biochemistry, Markey Cancer Center, University of Kentucky, Lexington, KY 40536-0509, USA
| | - Chunming Liu
- Department of Molecular and Cellular Biochemistry, Markey Cancer Center, University of Kentucky, Lexington, KY 40536-0509, USA
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27
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Abstract
Methylation of cytosine at the C5 position (5mC) represents an epigenetic modification that plays a fundamental role in embryonic development, transcriptional regulation, and other processes. It can also be a mutational hotspot at CpG dinucleotides as a result of spontaneous hydrolytic deamination of 5mC to thymine. The resulting G · T mismatch pair is recognized by thymine DNA glycosylase (TDG) and revereted to a G · C pair. Recent studies have shown that 5mC is consecutively catalyzed into 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC) by a DNA dioxygenase from the ten-eleven translocation (TET) family. Two oxidative cytosine derivatives, 5fC and 5caC, are eliminated by TDG during active DNA demethylation. Therefore, TDG has versatile roles in epigenetic regulation to control the gene expression as well as the DNA repair pathway to prevent mutagenesis. 5fC and 5caC serve as intermediate products of active DNA demethylation and also behave as DNA damages that threaten genomic integrity. Here, we discuss the potential functions of 5mC oxidative derivatives in epigenetic modification and DNA damage.
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Affiliation(s)
- Shinsuke Ito
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan.
| | - Isao Kuraoka
- Graduate School of Engineering Science, Osaka University Graduate School of Engineering Science, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
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28
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Goto M, Shinmura K, Matsushima Y, Ishino K, Yamada H, Totsuka Y, Matsuda T, Nakagama H, Sugimura H. Human DNA glycosylase enzyme TDG repairs thymine mispaired with exocyclic etheno-DNA adducts. Free Radic Biol Med 2014; 76:136-46. [PMID: 25151120 DOI: 10.1016/j.freeradbiomed.2014.07.044] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 07/14/2014] [Accepted: 07/31/2014] [Indexed: 11/24/2022]
Abstract
Lipid peroxidation directly reacts with DNA and produces various exocyclic etheno-base DNA adducts, some of which are considered to contribute to carcinogenesis. However, the system for repairing them in humans is largely unknown. We hypothesized that etheno-DNA adducts are repaired by base excision repair initiated by DNA glycosylase. To test this hypothesis, we examined the activities of the DNA glycosylase proteins OGG1, SMUG1, TDG, NEIL1, MUTYH, NTH1, MPG, and UNG2 against double-stranded oligonucleotides containing 1,N(6)-ethenoadenine (εA), 3,N(4)-ethenocytosine (εC), butanone-ethenocytosine (BεC), butanone-ethenoguanine (BεG), heptanone-ethenocytosine (HεC), or heptanone-ethenoguanine (HεG) using a DNA cleavage assay. We found that TDG is capable of removing thymine that has mispaired with εC, BεC, BεG, HεC, or HεG in vitro. We next examined the effect of TDG against etheno-DNA adducts in human cells. TDG-knockdown cells exhibited the following characteristics: (a) higher resistance to cell death caused by the induction of etheno-DNA adducts; (b) lower repair activity for εC; and (c) a modest acceleration of mutations caused by εC, compared with the rate in control cells. All these characteristics suggest that TDG exerts a repair activity against etheno-DNA adducts in human cells. These results suggest that TDG has novel repair activities toward etheno-DNA adducts.
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Affiliation(s)
- Masanori Goto
- Division of Cancer Development System, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan; Department of Tumor Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi Ward, Hamamatsu, Shizuoka 431-3192, Japan
| | - Kazuya Shinmura
- Department of Tumor Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi Ward, Hamamatsu, Shizuoka 431-3192, Japan.
| | - Yoshitaka Matsushima
- Department of Chemistry, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi Ward, Hamamatsu, Shizuoka 431-3192, Japan
| | - Kousuke Ishino
- Division of Cancer Development System, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan; Department of Pathology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan
| | - Hidetaka Yamada
- Department of Tumor Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi Ward, Hamamatsu, Shizuoka 431-3192, Japan
| | - Yukari Totsuka
- Division of Cancer Development System, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
| | - Tomonari Matsuda
- Research Center for Environmental Quality Management, Kyoto University, Otsu, Shiga, 520-0811, Japan
| | - Hitoshi Nakagama
- Division of Cancer Development System, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
| | - Haruhiko Sugimura
- Department of Tumor Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi Ward, Hamamatsu, Shizuoka 431-3192, Japan.
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29
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Wang J, Tang J, Lai M, Zhang H. 5-Hydroxymethylcytosine and disease. Mutat Res Rev Mutat Res 2014; 762:167-75. [PMID: 25475423 DOI: 10.1016/j.mrrev.2014.09.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 08/27/2014] [Accepted: 09/29/2014] [Indexed: 11/27/2022]
Abstract
Epigenetics is the study of inherited changes in phenotype or gene expression that do not alter DNA sequence. Recently, scientists have focused their attention on 5-hydroxymethylcytosine (5hmC), a newly discovered epigenetic marker, also known as sixth DNA base of the genome. In mammals, this novel epigenetic marker is derived from 5-methylcytosine (5mC) in a process catalyzed by ten-eleven translocation (TET) enzymes. Although 5hmC has only been subjected to study for a short while, a great deal of data has been accumulated regarding its generation, distribution, demethylation, function, and disease implications. All this information suggested that 5hmC acts not only as an intermediate in the DNA demethylation process but also as an independent epigenetic marker, playing an important role in the regulation of gene expression. This review focuses on recent progress in the study of the relationship between 5hmC and human diseases, such as cancer and Rett syndrome (RTT).
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Affiliation(s)
- Jingyu Wang
- Department of Pathology, School of Medicine, Zhejiang University, Zhejiang, PR China; Department of Pathology, The First Hospital of Jiaxing, Zhejiang, PR China
| | - Jinlong Tang
- Department of Pathology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang, PR China
| | - Maode Lai
- Department of Pathology, School of Medicine, Zhejiang University, Zhejiang, PR China; Key Laboratory of Disease Proteomics of Zhejiang Province, PR China.
| | - Honghe Zhang
- Department of Pathology, School of Medicine, Zhejiang University, Zhejiang, PR China; Key Laboratory of Disease Proteomics of Zhejiang Province, PR China.
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30
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Jia Y, Nie F, Du A, Chen Z, Qin Y, Huang T, Song X, Li L. Thymine DNA glycosylase promotes transactivation of β-catenin/TCFs by cooperating with CBP. J Mol Cell Biol 2014; 6:231-9. [PMID: 24748645 DOI: 10.1093/jmcb/mju014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Thymine DNA glycosylase (TDG), an enzyme that initiates the repair of G/T and G/U mismatches, has been lately found crucial in embryonic development to maintain epigenetic stability and facilitate the active DNA demethylation. Here we report a novel role of TDG in Wnt signaling as a transcriptional coactivator of β-catenin/TCFs complex. Our data show that TDG binds to the transcriptional factor family LEF1/TCFs and potentiates β-catenin/TCFs transactivation, while TDG depletion suppresses Wnt3a-stimulated reporter activity or target gene transcription. Next, we show that CBP, a known coactivator, is also required for TDG function through forming a cooperative complex on target promoters. Moreover, there is an elevation of TDG levels in human colon cancer tissue, and knockdown of TDG inhibits proliferation of the colon cells. Overall, our results reveal that TDG, as a new coactivator, promotes β-catenin/TCFs transactivation and functionally cooperates with CBP in canonical Wnt signaling.
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Affiliation(s)
- Yingying Jia
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Fen Nie
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Aiying Du
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhangcheng Chen
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yuanbo Qin
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Tao Huang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiaomin Song
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lin Li
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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31
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Gregory DJ, Zhang Y, Kobzik L, Fedulov AV. Specific transcriptional enhancement of inducible nitric oxide synthase by targeted promoter demethylation. Epigenetics 2013; 8:1205-12. [PMID: 24008769 DOI: 10.4161/epi.26267] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The ability to specifically reactivate epigenetically silenced genes would have great utility in experimental studies and potential therapeutic value. Here, we describe the specific targeting of thymidine DNA glycosylase (TDG), an enzyme involved in the mechanism of methylcytosine demethylation, to the promoter of Nos2, a gene silenced by methylation in fibroblasts, using artificial zinc finger DNA binding domains. Individual targeted TDG constructs had a small effect on Nos2 expression and methylation, but simultaneous targeting of a quartet of TDG constructs significantly restored responsiveness to LPS and IFN stimuli in association with marked cytosine demethylation at the promoter and CpG island; catalytically inactive TDG complexes had no effect. Whole-genome expression microarray and pathway analysis found only 42 genes that were affected by targeted TDG constructs; the majority are likely downstream of the effect on Nos2. This study therefore shows highly specific, directed reactivation of a single, silenced gene by targeting of a demethylase to the promoter.
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Affiliation(s)
- David J Gregory
- Department of Environmental Health; MIPS Program; Harvard School of Public Health; Boston, MA USA
| | - Yiming Zhang
- Department of Medicine; Division of Pulmonary and Critical Care Medicine; Brigham and Women's Hospital; Harvard Medical School; Boston, MA USA
| | - Lester Kobzik
- Department of Environmental Health; MIPS Program; Harvard School of Public Health; Boston, MA USA
| | - Alexey V Fedulov
- Department of Medicine; Division of Pulmonary and Critical Care Medicine; Brigham and Women's Hospital; Harvard Medical School; Boston, MA USA
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32
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Gavin DP, Chase KA, Sharma RP. Active DNA demethylation in post-mitotic neurons: a reason for optimism. Neuropharmacology 2013; 75:233-45. [PMID: 23958448 DOI: 10.1016/j.neuropharm.2013.07.036] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 07/22/2013] [Accepted: 07/30/2013] [Indexed: 12/13/2022]
Abstract
Over the last several years proteins involved in base excision repair (BER) have been implicated in active DNA demethylation. We review the literature supporting BER as a means of active DNA demethylation, and explain how the various components function and cooperate to remove the potentially most enduring means of epigenetic gene regulation. Recent evidence indicates that the same pathways implicated during periods of widespread DNA demethylation, such as the erasure of methyl marks in the paternal pronucleus soon after fertilization, are operational in post-mitotic neurons. Neuronal functional identities, defined here as the result of a combination of neuronal subtype, location, and synaptic connections are largely maintained through DNA methylation. Chronic mental illnesses, such as schizophrenia, may be the result of both altered neurotransmitter levels and neurons that have assumed dysfunctional neuronal identities. A limitation of most current psychopharmacological agents is their focus on the former, while not addressing the more profound latter pathophysiological process. Previously, it was believed that active DNA demethylation in post-mitotic neurons was rare if not impossible. If this were the case, then reversing the factors that maintain neuronal identity, would be highly unlikely. The emergence of an active DNA demethylation pathway in the brain is a reason for great optimism in psychiatry as it provides a means by which previously pathological neurons may be reprogrammed to serve a more favorable role. Agents targeting epigenetic processes have shown much promise in this regard, and may lead to substantial gains over traditional pharmacological approaches.
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Affiliation(s)
- David P Gavin
- The Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, 1601 W. Taylor St., Chicago, IL 60612, USA; Jesse Brown Veterans Affairs Medical Center, 820 South Damen Avenue (M/C 151), Chicago, IL 60612, USA.
| | - Kayla A Chase
- The Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, 1601 W. Taylor St., Chicago, IL 60612, USA
| | - Rajiv P Sharma
- The Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, 1601 W. Taylor St., Chicago, IL 60612, USA; Jesse Brown Veterans Affairs Medical Center, 820 South Damen Avenue (M/C 151), Chicago, IL 60612, USA
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Zhang P, Huang B, Xu X, Sessa WC. Ten-eleven translocation (Tet) and thymine DNA glycosylase ( TDG), components of the demethylation pathway, are direct targets of miRNA-29a. Biochem Biophys Res Commun 2013; 437:368-73. [PMID: 23820384 DOI: 10.1016/j.bbrc.2013.06.082] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 06/21/2013] [Indexed: 11/21/2022]
Abstract
The ten-eleven translocation family of proteins (Tet1/2/3, Tets) converts 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), which can be further oxidized and repaired by thymine DNA glycosylase (TDG), to influence gene transcription in embryonic and adult tissues. However the mechanisms of how Tets and TDG levels are regulated are unknown. We show that miR-29 can directly regulate Tet1-3 and TDG mRNA levels through binding to their 3'UTRs. miR-29 mimic decreases global 5hmC levels, a hallmark of Tet activity. Moreover, the mRNA levels for Tet3 and TDG are inversely correlated with the levels of miR-29 in aged mouse aorta implying that aging may affect methylation patterns via miRNA. In summary, our data show that Tets and TDG are direct targets of miR-29 and unravel a novel regulatory role for this miRNA in epigenetic DNA demethylation pathways.
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Graham JS, Schoneboom BA. Historical perspective on effects and treatment of sulfur mustard injuries. Chem Biol Interact. 2013;206:512-522. [PMID: 23816402 DOI: 10.1016/j.cbi.2013.06.013] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 06/18/2013] [Accepted: 06/20/2013] [Indexed: 12/11/2022]
Abstract
Sulfur mustard (2,2'-dichlorodiethyl sulfide; SM) is a potent vesicating chemical warfare agent that poses a continuing threat to both military and civilian populations. Significant SM injuries can take several months to heal, necessitate lengthy hospitalizations, and result in long-term complications affecting the skin, eyes, and lungs. This report summarizes initial and ongoing (chronic) clinical findings from SM casualties from the Iran-Iraq War (1980-1988), with an emphasis on cutaneous injury. In addition, we describe the cutaneous manifestations and treatment of several men recently and accidentally exposed to SM in the United States. Common, chronic cutaneous problems being reported in the Iranian casualties include pruritis (the primary complaint), burning, pain, redness, desquamation, hyperpigmentation, hypopigmentation, erythematous papular rash, xerosis, multiple cherry angiomas, atrophy, dermal scarring, hypertrophy, and sensitivity to mechanical injury with recurrent blistering and ulceration. Chronic ocular problems include keratitis, photophobia, persistent tearing, sensation of foreign body, corneal thinning and ulceration, vasculitis of the cornea and conjunctiva, and limbal stem cell deficiency. Chronic pulmonary problems include decreases in lung function, bronchitis with hyper-reactive airways, bronchiolitis, bronchiectasis, stenosis of the trachea and other large airways, emphysema, pulmonary fibrosis, decreased total lung capacity, and increased incidences of lung cancer, pulmonary infections, and tuberculosis. There are currently no standardized or optimized methods of casualty management; current treatment strategy consists of symptomatic management and is designed to relieve symptoms, prevent infections, and promote healing. New strategies are needed to provide for optimal and rapid healing, with the goals of (a) returning damaged tissue to optimal appearance and normal function in the shortest period of time, and (b) ameliorating chronic effects. Further experimental research and clinical trials will be needed to prevent or mitigate the acute clinical effects of SM exposure and to reduce or eliminate the long-term manifestations.
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Abstract
Prior to activation of the embryonic genome, the initiating events of mammalian development are under maternal control and include fertilization, the block to polyspermy and processing sperm DNA. Following gamete union, the transcriptionally inert sperm DNA is repackaged into the male pronucleus which fuses with the female pronucleus to form a 1-cell zygote. Embryonic transcription begins during the maternal to zygotic transfer of control in directing development. This transition occurs at species-specific times after one or several rounds of blastomere cleavage and is essential for normal development. However, even after activation of the embryonic genome, successful development relies on stored maternal components without which embryos fail to progress beyond initial cell divisions. Better understanding of the molecular basis of maternal to zygotic transition including fertilization, the activation of the embryonic genome and cleavage-stage development will provide insight into early human development that should translate into clinical applications for regenerative medicine and assisted reproductive technologies.
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Affiliation(s)
- Lei Li
- Division of Molecular Embryonic Development, State Key Laboratory of Reproductive Biology, Institute of Zoology/Chinese Academy of Sciences, Beijing 100101, PR China.
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