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Ma J, Qi R, Harcourt EM, Chen YT, Barbosa GM, Peng Z, Howarth S, Delaney S, Li D. 3,N4-Etheno-5-methylcytosine blocks TET1-3 oxidation but is repaired by ALKBH2, 3 and FTO. Nucleic Acids Res 2024:gkae818. [PMID: 39315710 DOI: 10.1093/nar/gkae818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 09/04/2024] [Accepted: 09/11/2024] [Indexed: 09/25/2024] Open
Abstract
5-Methyldeoxycytidine (5mC) is a major epigenetic marker that regulates cellular functions in mammals. Endogenous lipid peroxidation can convert 5mC into 3,N4-etheno-5-methylcytosine (ϵ5mC). ϵ5mC is structurally similar to the mutagenic analog 3,N4-ethenocytosine (ϵC), which is repaired by AlkB family enzymes in the direct reversal repair (DRR) pathway and excised by DNA glycosylases in the base excision repair (BER) pathway. However, the repair of ϵ5mC has not been reported. Here, we examined the activities against ϵ5mC by DRR and BER enzymes and TET1-3, enzymes that modify the 5-methyl group in 5mC. We found that the etheno modification of 5mC blocks oxidation by TET1-3. Conversely, three human homologs in the AlkB family, ALKBH2, 3 and FTO were able to repair ϵ5mC to 5mC, which was subsequently modified by TET1 to 5-hydroxymethylcytosine. We also demonstrated that ALKBH2 likely repairs ϵ5mC in MEF cells. Another homolog, ALKBH5, could not repair ϵ5mC. Also, ϵ5mC is not a substrate for BER glycosylases SMUG1, AAG, or TDG. These findings indicate DRR committed by ALKBH2, 3 and FTO could reduce the detrimental effects of ϵ5mC in genetics and epigenetics and may work together with TET enzymes to modulate epigenetic regulations.
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Affiliation(s)
- Jian Ma
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston RI 02881, USA
| | - Rui Qi
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston RI 02881, USA
| | - Emily M Harcourt
- Department of Chemistry, Le Moyne College, Syracuse, NY 13214, USA
| | - Yi-Tzai Chen
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston RI 02881, USA
| | | | - Zhiyuan Peng
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston RI 02881, USA
| | - Samuel Howarth
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston RI 02881, USA
| | - Sarah Delaney
- Department of Chemistry, Brown University, Providence, RI 02912, USA
| | - Deyu Li
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston RI 02881, USA
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2
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Pal S, Yuvaraj R, Krishnan H, Venkatraman B, Abraham J, Gopinathan A. Unraveling radiation resistance strategies in two bacterial strains from the high background radiation area of Chavara-Neendakara: A comprehensive whole genome analysis. PLoS One 2024; 19:e0304810. [PMID: 38857267 PMCID: PMC11164402 DOI: 10.1371/journal.pone.0304810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 05/18/2024] [Indexed: 06/12/2024] Open
Abstract
This paper reports the results of gamma irradiation experiments and whole genome sequencing (WGS) performed on vegetative cells of two radiation resistant bacterial strains, Metabacillus halosaccharovorans (VITHBRA001) and Bacillus paralicheniformis (VITHBRA024) (D10 values 2.32 kGy and 1.42 kGy, respectively), inhabiting the top-ranking high background radiation area (HBRA) of Chavara-Neendakara placer deposit (Kerala, India). The present investigation has been carried out in the context that information on strategies of bacteria having mid-range resistance for gamma radiation is inadequate. WGS, annotation, COG and KEGG analyses and manual curation of genes helped us address the possible pathways involved in the major domains of radiation resistance, involving recombination repair, base excision repair, nucleotide excision repair and mismatch repair, and the antioxidant genes, which the candidate could activate to survive under ionizing radiation. Additionally, with the help of these data, we could compare the candidate strains with that of the extremely radiation resistant model bacterium Deinococccus radiodurans, so as to find the commonalities existing in their strategies of resistance on the one hand, and also the rationale behind the difference in D10, on the other. Genomic analysis of VITHBRA001 and VITHBRA024 has further helped us ascertain the difference in capability of radiation resistance between the two strains. Significantly, the genes such as uvsE (NER), frnE (protein protection), ppk1 and ppx (non-enzymatic metabolite production) and those for carotenoid biosynthesis, are endogenous to VITHBRA001, but absent in VITHBRA024, which could explain the former's better radiation resistance. Further, this is the first-time study performed on any bacterial population inhabiting an HBRA. This study also brings forward the two species whose radiation resistance has not been reported thus far, and add to the knowledge on radiation resistant capabilities of the phylum Firmicutes which are abundantly observed in extreme environment.
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Affiliation(s)
- Sowptika Pal
- Molecular Endocrinology Laboratory, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India
| | - Ramani Yuvaraj
- Radiological and Environmental Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu, India
| | - Hari Krishnan
- Radiological and Environmental Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu, India
| | - Balasubramanian Venkatraman
- Radiological and Environmental Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu, India
| | - Jayanthi Abraham
- Microbial Biotechnology Laboratory, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India
| | - Anilkumar Gopinathan
- Molecular Endocrinology Laboratory, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India
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3
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Zhang Z, Wei W, Chen S, Yang J, Song D, Chen Y, Zhao Z, Chen J, Wang F, Wang J, Li Z, Liang Y, Yu H. Chemoenzymatic Installation of Site-Specific Chemical Groups on DNA Enhances the Catalytic Activity. J Am Chem Soc 2024; 146:7052-7062. [PMID: 38427585 DOI: 10.1021/jacs.4c00484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
Abstract
Functional DNAs are valuable molecular tools in chemical biology and analytical chemistry but suffer from low activities due to their limited chemical functionalities. Here, we present a chemoenzymatic method for site-specific installation of diverse functional groups on DNA, and showcase the application of this method to enhance the catalytic activity of a DNA catalyst. Through chemoenzymatic introduction of distinct chemical groups, such as hydroxyl, carboxyl, and benzyl, at specific positions, we achieve significant enhancements in the catalytic activity of the RNA-cleaving deoxyribozyme 10-23. A single carboxyl modification results in a 100-fold increase, while dual modifications (carboxyl and benzyl) yield an approximately 700-fold increase in activity when an RNA cleavage reaction is catalyzed on a DNA-RNA chimeric substrate. The resulting dually modified DNA catalyst, CaBn, exhibits a kobs of 3.76 min-1 in the presence of 1 mM Mg2+ and can be employed for fluorescent imaging of intracellular magnesium ions. Molecular dynamics simulations reveal the superior capability of CaBn to recruit magnesium ions to metal-ion-binding site 2 and adopt a catalytically competent conformation. Our work provides a broadly accessible strategy for DNA functionalization with diverse chemical modifications, and CaBn offers a highly active DNA catalyst with immense potential in chemistry and biotechnology.
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Affiliation(s)
- Ze Zhang
- State Key Laboratory of Coordination Chemistry, Department of Biomedical Engineering, College of Engineering and Applied Sciences, Chemistry and Biomedicine Innovation Center (ChemBIC), Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China
| | - Wanqing Wei
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China
| | - Siqi Chen
- State Key Laboratory of Coordination Chemistry, Department of Biomedical Engineering, College of Engineering and Applied Sciences, Chemistry and Biomedicine Innovation Center (ChemBIC), Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China
| | - Jintao Yang
- State Key Laboratory of Coordination Chemistry, Department of Biomedical Engineering, College of Engineering and Applied Sciences, Chemistry and Biomedicine Innovation Center (ChemBIC), Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China
| | - Dongfan Song
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yinghan Chen
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Zerun Zhao
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Jiawen Chen
- State Key Laboratory of Coordination Chemistry, Department of Biomedical Engineering, College of Engineering and Applied Sciences, Chemistry and Biomedicine Innovation Center (ChemBIC), Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China
| | - Fulong Wang
- State Key Laboratory of Coordination Chemistry, Department of Biomedical Engineering, College of Engineering and Applied Sciences, Chemistry and Biomedicine Innovation Center (ChemBIC), Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China
| | - Jiahuan Wang
- State Key Laboratory of Coordination Chemistry, Department of Biomedical Engineering, College of Engineering and Applied Sciences, Chemistry and Biomedicine Innovation Center (ChemBIC), Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China
| | - Zhe Li
- State Key Laboratory of Analytical Chemistry for Life Science, Department of Biomedical Engineering, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210023, China
| | - Yong Liang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Hanyang Yu
- State Key Laboratory of Coordination Chemistry, Department of Biomedical Engineering, College of Engineering and Applied Sciences, Chemistry and Biomedicine Innovation Center (ChemBIC), Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China
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4
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Pagano A, Kunz L, Dittmann A, Araújo SDS, Macovei A, Shridhar Gaonkar S, Sincinelli F, Wazeer H, Balestrazzi A. Changes in Medicago truncatula seed proteome along the rehydration-dehydration cycle highlight new players in the genotoxic stress response. FRONTIERS IN PLANT SCIENCE 2023; 14:1188546. [PMID: 37409306 PMCID: PMC10319343 DOI: 10.3389/fpls.2023.1188546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 05/24/2023] [Indexed: 07/07/2023]
Abstract
Introduction Several molecular aspects underlying the seed response to priming and the resulting vigor profile are still poorly understood. Mechanisms involved in genome maintenance deserve attention since the balance between stimulation of germination and DNA damage accumulation versus active repair is a key determinant for designing successful seed priming protocols. Methods Changes in the Medicago truncatula seed proteome were investigated in this study, using discovery mass spectrometry and label-free quantification, along the rehydration-dehydration cycle of a standard vigorization treatment (hydropriming plus dry-back), and during post-priming imbibition. Resuts and discussion From 2056 to 2190 proteins were detected in each pairwise comparison, among which six were differentially accumulated and 36 were detected only in one condition. The following proteins were selected for further investigation: MtDRP2B (DYNAMIN-RELATED PROTEIN), MtTRXm4 (THIOREDOXIN m4), and MtASPG1 (ASPARTIC PROTEASE IN GUARD CELL 1) showing changes in seeds under dehydration stress; MtITPA (INOSINE TRIPHOSPHATE PYROPHOSPHORYLASE), MtABA2 (ABSCISIC ACID DEFICIENT 2), MtRS2Z32 (SERINE/ARGININE-RICH SPLICING FACTOR RS2Z32), and MtAQR (RNA HELICASE AQUARIUS) that were differentially regulated during post-priming imbibition. Changes in the corresponding transcript levels were assessed by qRT-PCR. In animal cells, ITPA hydrolyses 2'-deoxyinosine triphosphate and other inosine nucleotides, preventing genotoxic damage. A proof of concept was performed by imbibing primed and control M. truncatula seeds in presence/absence of 20 mM 2'-deoxyinosine (dI). Results from comet assay highlighted the ability of primed seeds to cope with dI-induced genotoxic damage. The seed repair response was assessed by monitoring the expression profiles of MtAAG (ALKYL-ADENINE DNA GLYCOSILASE) and MtEndoV (ENDONUCLEASE V) genes that participate in the repair of the mismatched I:T pair in BER (base excision repair) and AER (alternative excision repair) pathways, respectively.
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Affiliation(s)
- Andrea Pagano
- Department of Biology and Biotechnology ‘L. Spallanzani’, University of Pavia, Pavia, Italy
| | - Laura Kunz
- Functional Genomics Center Zurich (FGCZ), University of Zurich/Eidgenossische Technische Hochschule (ETH) Zurich, Zurich, Switzerland
| | - Antje Dittmann
- Functional Genomics Center Zurich (FGCZ), University of Zurich/Eidgenossische Technische Hochschule (ETH) Zurich, Zurich, Switzerland
| | - Susana De Sousa Araújo
- Association BLC3 - Campus of Technology and Innovation, Centre BIO R&D Unit | North Delegation, Macedo de Cavaleiros, Portugal
| | - Anca Macovei
- Department of Biology and Biotechnology ‘L. Spallanzani’, University of Pavia, Pavia, Italy
- National Biodiversity Future Center (NBFC), Palermo, Italy
| | | | - Federico Sincinelli
- Department of Biology and Biotechnology ‘L. Spallanzani’, University of Pavia, Pavia, Italy
| | - Hisham Wazeer
- Department of Biology and Biotechnology ‘L. Spallanzani’, University of Pavia, Pavia, Italy
| | - Alma Balestrazzi
- Department of Biology and Biotechnology ‘L. Spallanzani’, University of Pavia, Pavia, Italy
- National Biodiversity Future Center (NBFC), Palermo, Italy
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5
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Schmaltz LF, Koag MC, Kou Y, Zhang L, Lee S. Genotoxic effects of the major alkylation damage N7-methylguanine and methyl formamidopyrimidine. Biochem J 2023; 480:573-585. [PMID: 37078496 PMCID: PMC11061863 DOI: 10.1042/bcj20220460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 03/29/2023] [Accepted: 04/19/2023] [Indexed: 04/21/2023]
Abstract
Various alkylating agents are known to preferentially modify guanine in DNA, resulting in the formation of N7-alkylguanine (N7-alkylG) and the imidazole ring opened alkyl-formamidopyrimidine (alkyl-FapyG) lesions. Evaluating the mutagenic effects of N7-alkylG has been challenging due to the instability of the positively charged N7-alkylG. To address this issue, we developed a 2'-fluorine-mediated transition-state destabilization approach, which stabilizes N7-alkylG and prevents spontaneous depurination. We also developed a postsynthetic conversion of 2'-F-N7-alkylG DNA into 2'-F-alkyl-FapyG DNA. Using these methods, we incorporated site-specific N7-methylG and methyl-FapyG into pSP189 plasmid and determined their mutagenic properties in bacterial cells using the supF-based colony screening assay. The mutation frequency of N7-methylG was found to be less than 0.5%. Our crystal structure analysis revealed that N7-methylation did not significantly alter base pairing properties, as evidenced by a correct base pairing between 2'-F-N7-methylG and dCTP in Dpo4 polymerase catalytic site. In contrast, the mutation frequency of methyl-FapyG was 6.3%, highlighting the mutagenic nature of this secondary lesion. Interestingly, all mutations arising from methyl-FapyG in the 5'-GGT(methyl-FapyG)G-3' context were single nucleotide deletions at the 5'-G of the lesion. Overall, our results demonstrate that 2'-fluorination technology is a useful tool for studying the chemically labile N7-alkylG and alkyl-FapyG lesions.
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Affiliation(s)
- Lillian F Schmaltz
- From the Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, U.S.A
| | - Myong-Chul Koag
- From the Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, U.S.A
| | - Yi Kou
- From the Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, U.S.A
| | - Louis Zhang
- From the Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, U.S.A
| | - Seongmin Lee
- From the Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, U.S.A
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6
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Collins A, Møller P, Gajski G, Vodenková S, Abdulwahed A, Anderson D, Bankoglu EE, Bonassi S, Boutet-Robinet E, Brunborg G, Chao C, Cooke MS, Costa C, Costa S, Dhawan A, de Lapuente J, Bo' CD, Dubus J, Dusinska M, Duthie SJ, Yamani NE, Engelward B, Gaivão I, Giovannelli L, Godschalk R, Guilherme S, Gutzkow KB, Habas K, Hernández A, Herrero O, Isidori M, Jha AN, Knasmüller S, Kooter IM, Koppen G, Kruszewski M, Ladeira C, Laffon B, Larramendy M, Hégarat LL, Lewies A, Lewinska A, Liwszyc GE, de Cerain AL, Manjanatha M, Marcos R, Milić M, de Andrade VM, Moretti M, Muruzabal D, Novak M, Oliveira R, Olsen AK, Owiti N, Pacheco M, Pandey AK, Pfuhler S, Pourrut B, Reisinger K, Rojas E, Rundén-Pran E, Sanz-Serrano J, Shaposhnikov S, Sipinen V, Smeets K, Stopper H, Teixeira JP, Valdiglesias V, Valverde M, van Acker F, van Schooten FJ, Vasquez M, Wentzel JF, Wnuk M, Wouters A, Žegura B, Zikmund T, Langie SAS, Azqueta A. Measuring DNA modifications with the comet assay: a compendium of protocols. Nat Protoc 2023; 18:929-989. [PMID: 36707722 PMCID: PMC10281087 DOI: 10.1038/s41596-022-00754-y] [Citation(s) in RCA: 106] [Impact Index Per Article: 106.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 07/05/2022] [Indexed: 01/28/2023]
Abstract
The comet assay is a versatile method to detect nuclear DNA damage in individual eukaryotic cells, from yeast to human. The types of damage detected encompass DNA strand breaks and alkali-labile sites (e.g., apurinic/apyrimidinic sites), alkylated and oxidized nucleobases, DNA-DNA crosslinks, UV-induced cyclobutane pyrimidine dimers and some chemically induced DNA adducts. Depending on the specimen type, there are important modifications to the comet assay protocol to avoid the formation of additional DNA damage during the processing of samples and to ensure sufficient sensitivity to detect differences in damage levels between sample groups. Various applications of the comet assay have been validated by research groups in academia, industry and regulatory agencies, and its strengths are highlighted by the adoption of the comet assay as an in vivo test for genotoxicity in animal organs by the Organisation for Economic Co-operation and Development. The present document includes a series of consensus protocols that describe the application of the comet assay to a wide variety of cell types, species and types of DNA damage, thereby demonstrating its versatility.
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Affiliation(s)
- Andrew Collins
- Department of Nutrition, University of Oslo, Oslo, Norway
| | - Peter Møller
- Department of Public Health, Section of Environmental Health, University of Copenhagen, Copenhagen, Denmark
| | - Goran Gajski
- Mutagenesis Unit, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Soňa Vodenková
- Department of Molecular Biology of Cancer, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czech Republic
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Abdulhadi Abdulwahed
- Oxidative Stress Group, Department of Environmental Health Sciences, Florida International University, Miami, FL, USA
| | - Diana Anderson
- Biomedical Sciences Department, University of Bradford, Bradford, UK
| | - Ezgi Eyluel Bankoglu
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Stefano Bonassi
- Department of Human Sciences and Quality of Life Promotion, San Raffaele University, Rome, Italy
- Unit of Clinical and Molecular Epidemiology, IRCCS San Raffaele Roma, Rome, Italy
| | - Elisa Boutet-Robinet
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Gunnar Brunborg
- Division of Climate and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
- Centre for Environmental Radioactivity (CoE CERAD 223268/50), Oslo, Norway
| | - Christy Chao
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Marcus S Cooke
- Oxidative Stress Group, Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Carla Costa
- Environmental Health Department, National Institute of Health, Porto, Portugal
- EPIUnit - Instituto de Saúde Pública, Universidade do Porto, Porto, Portugal
- Laboratory for Integrative and Translational Research in Population Health (ITR), Porto, Portugal
| | - Solange Costa
- Environmental Health Department, National Institute of Health, Porto, Portugal
- EPIUnit - Instituto de Saúde Pública, Universidade do Porto, Porto, Portugal
- Laboratory for Integrative and Translational Research in Population Health (ITR), Porto, Portugal
| | - Alok Dhawan
- Centre of BioMedical Research, SGPGIMS Campus, Lucknow, India
| | - Joaquin de Lapuente
- Toxicology Department, AC MARCA Group, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Cristian Del Bo'
- Department of Food, Environmental and Nutritional Sciences, Università degli Studi di Milano, Milan, Italy
| | - Julien Dubus
- Aix-Marseille University, CEA, CNRS, Institute of Biosciences and Biotechnologies of Aix-Marseille, Saint-Paul-Lez-Durance, France
| | - Maria Dusinska
- Health Effects Laboratory, Department of Environmental Chemistry, NILU-Norwegian Institute for Air Research, Kjeller, Norway
| | - Susan J Duthie
- School of Pharmacy and Life Sciences, The Robert Gordon University, Aberdeen, Scotland
| | - Naouale El Yamani
- Health Effects Laboratory, Department of Environmental Chemistry, NILU-Norwegian Institute for Air Research, Kjeller, Norway
| | - Bevin Engelward
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Isabel Gaivão
- Genetics and Biotechnology Department and Veterinary and Animal Research Centre (CECAV), Universidade de Trás-os-Montes e Alto Douro, Vila Real, Portugal
| | - Lisa Giovannelli
- Department NEUROFARBA, Section Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Roger Godschalk
- Department of Pharmacology & Toxicology, School for Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Sofia Guilherme
- Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Kristine B Gutzkow
- Division of Climate and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
- Centre for Environmental Radioactivity (CoE CERAD 223268/50), Oslo, Norway
| | - Khaled Habas
- School of Chemistry and Bioscience, Faculty of Life Sciences, Bradford University, Bradford, UK
| | - Alba Hernández
- Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Cerdanyola de Vallès, Spain
| | - Oscar Herrero
- Biology and Environmental Toxicology Group, Faculty of Science, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
| | - Marina Isidori
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Caserta, Italy
| | - Awadhesh N Jha
- School of Biological and Marine Sciences, University of Plymouth, Plymouth, UK
| | - Siegfried Knasmüller
- Institute of Cancer Research, Internal Medicine I, Medical University Vienna, Vienna, Austria
| | - Ingeborg M Kooter
- Department Circular Economy and Environment, the Netherlands Organisation for Applied Scientific Research-TNO, Utrecht, The Netherlands
| | | | - Marcin Kruszewski
- Centre for Radiobiology and Biological Dosimetry, Institute of Nuclear Chemistry and Technology, Warsaw, Poland
- Department of Molecular Biology and Translational Research, Institute of Rural Health, Lublin, Poland
| | - Carina Ladeira
- H&TRC-Health & Technology Research Center, ESTeSL-Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal
- NOVA National School of Public Health, Public Health Research Centre, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Blanca Laffon
- Universidade da Coruña, Grupo DICOMOSA, CICA - Centro Interdisciplinar de Química e Bioloxía, Departamento de Psicología, Facultad de Ciencias de la Educación, A Coruña, Spain
- Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain
| | - Marcelo Larramendy
- Laboratory of Ecotoxicology, Faculty of Natural Sciences and Museum, National University of La Plata, La Plata, Argentina
| | - Ludovic Le Hégarat
- Anses, French Agency for Food, Environmental and Occupational Health and Safety, Fougeres Laboratory, Toxicology of Contaminants Unit, Fougères, France
| | - Angélique Lewies
- Department of Cardiothoracic Surgery, University of the Free State, Bloemfontein, South Africa
| | - Anna Lewinska
- Department of Biotechnology, University of Rzeszow, Rzeszow, Poland
| | - Guillermo E Liwszyc
- Laboratory of Ecotoxicology, Faculty of Natural Sciences and Museum, National University of La Plata, La Plata, Argentina
| | - Adela López de Cerain
- Department of Pharmacology and Toxicology, University of Navarra, Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, Pamplona, Spain
| | - Mugimane Manjanatha
- Food and Drug Administration, National Center for Toxicological Research, Division of Genetic and Molecular Toxicology, Jefferson, AR, USA
| | - Ricard Marcos
- Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Cerdanyola de Vallès, Spain
| | - Mirta Milić
- Mutagenesis Unit, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Vanessa Moraes de Andrade
- Translational Biomedicine Laboratory, Graduate Program of Health Sciences, University of Southern Santa Catarina, Criciuma, Brazil
| | - Massimo Moretti
- Department of Pharmaceutical Sciences, Unit of Public Health, University of Perugia, Perugia, Italy
| | - Damian Muruzabal
- Department of Pharmacology and Toxicology, University of Navarra, Pamplona, Spain
| | - Matjaž Novak
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia
| | - Rui Oliveira
- Department of Biology, CBMA-Centre of Molecular and Environmental Biology, University of Minho, Braga, Portugal
| | - Ann-Karin Olsen
- Division of Climate and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
- Centre for Environmental Radioactivity (CoE CERAD 223268/50), Oslo, Norway
| | - Norah Owiti
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mário Pacheco
- Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Alok K Pandey
- Nanomaterial Toxicology Group, CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Stefan Pfuhler
- Global Product Stewardship - Human Safety, The Procter & Gamble Co, Cincinnati, OH, USA
| | - Bertrand Pourrut
- Laboratoire Ecologie fonctionnelle et Environnement, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | | | - Emilio Rojas
- Department of Genomic Medicine and Environmental Toxicology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, CU, Mexico City, Mexico
| | - Elise Rundén-Pran
- Health Effects Laboratory, Department of Environmental Chemistry, NILU-Norwegian Institute for Air Research, Kjeller, Norway
| | - Julen Sanz-Serrano
- Department of Pharmacology and Toxicology, University of Navarra, Pamplona, Spain
| | | | - Ville Sipinen
- Norwegian Scientific Committee for Food and Environment, Oslo, Norway
| | - Karen Smeets
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Helga Stopper
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - João Paulo Teixeira
- Environmental Health Department, National Institute of Health, Porto, Portugal
- EPIUnit - Instituto de Saúde Pública, Universidade do Porto, Porto, Portugal
- Laboratory for Integrative and Translational Research in Population Health (ITR), Porto, Portugal
| | - Vanessa Valdiglesias
- Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain
- Universidade da Coruña, Grupo NanoToxGen, CICA - Centro Interdisciplinar de Química e Bioloxía, Departamento de Biología, Facultad de Ciencias, A Coruña, Spain
| | - Mahara Valverde
- Department of Genomic Medicine and Environmental Toxicology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, CU, Mexico City, Mexico
| | | | - Frederik-Jan van Schooten
- Department of Pharmacology & Toxicology, School for Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | | | | | - Maciej Wnuk
- Department of Biology, University of Rzeszow, Rzeszow, Poland
| | - Annelies Wouters
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Bojana Žegura
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia
| | - Tomas Zikmund
- Biocev, 1st Medical Faculty, Charles University, Vestec, Czech Republic
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Sabine A S Langie
- Department of Pharmacology & Toxicology, School for Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Amaya Azqueta
- Department of Pharmacology and Toxicology, University of Navarra, Pamplona, Spain.
- IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.
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7
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Fahrer J, Christmann M. DNA Alkylation Damage by Nitrosamines and Relevant DNA Repair Pathways. Int J Mol Sci 2023; 24:ijms24054684. [PMID: 36902118 PMCID: PMC10003415 DOI: 10.3390/ijms24054684] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/17/2023] [Accepted: 02/24/2023] [Indexed: 03/04/2023] Open
Abstract
Nitrosamines occur widespread in food, drinking water, cosmetics, as well as tobacco smoke and can arise endogenously. More recently, nitrosamines have been detected as impurities in various drugs. This is of particular concern as nitrosamines are alkylating agents that are genotoxic and carcinogenic. We first summarize the current knowledge on the different sources and chemical nature of alkylating agents with a focus on relevant nitrosamines. Subsequently, we present the major DNA alkylation adducts induced by nitrosamines upon their metabolic activation by CYP450 monooxygenases. We then describe the DNA repair pathways engaged by the various DNA alkylation adducts, which include base excision repair, direct damage reversal by MGMT and ALKBH, as well as nucleotide excision repair. Their roles in the protection against the genotoxic and carcinogenic effects of nitrosamines are highlighted. Finally, we address DNA translesion synthesis as a DNA damage tolerance mechanism relevant to DNA alkylation adducts.
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Affiliation(s)
- Jörg Fahrer
- Division of Food Chemistry and Toxicology, Department of Chemistry, RPTU Kaiserslautern-Landau, Erwin-Schrödinger Strasse 52, D-67663 Kaiserslautern, Germany
- Correspondence: (J.F.); (M.C.); Tel.: +496312052974 (J.F.); Tel: +496131179066 (M.C.)
| | - Markus Christmann
- Department of Toxicology, University Medical Center Mainz, Obere Zahlbacher Strasse 67, D-55131 Mainz, Germany
- Correspondence: (J.F.); (M.C.); Tel.: +496312052974 (J.F.); Tel: +496131179066 (M.C.)
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8
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Jang S, Kumar N, Schaich MA, Zhong Z, van Loon B, Watkins S, Van Houten B. Cooperative interaction between AAG and UV-DDB in the removal of modified bases. Nucleic Acids Res 2022; 50:12856-12871. [PMID: 36511855 PMCID: PMC9825174 DOI: 10.1093/nar/gkac1145] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 11/05/2022] [Accepted: 11/16/2022] [Indexed: 12/15/2022] Open
Abstract
UV-DDB is a DNA damage recognition protein recently discovered to participate in the removal of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxoG) by stimulating multiple steps of base excision repair (BER). In this study, we examined whether UV-DDB has a wider role in BER besides oxidized bases and found it has specificity for two known DNA substrates of alkyladenine glycosylase (AAG)/N-methylpurine DNA glycosylase (MPG): 1, N6-ethenoadenine (ϵA) and hypoxanthine. Gel mobility shift assays show that UV-DDB recognizes these two lesions 4-5 times better than non-damaged DNA. Biochemical studies indicated that UV-DDB stimulated AAG activity on both substrates by 4- to 5-fold. Native gels indicated UV-DDB forms a transient complex with AAG to help facilitate release of AAG from the abasic site product. Single molecule experiments confirmed the interaction and showed that UV-DDB can act to displace AAG from abasic sites. Cells when treated with methyl methanesulfonate resulted in foci containing AAG and UV-DDB that developed over the course of several hours after treatment. While colocalization did not reach 100%, foci containing AAG and UV-DDB reached a maximum at three hours post treatment. Together these data indicate that UV-DDB plays an important role in facilitating the repair of AAG substrates.
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Affiliation(s)
- Sunbok Jang
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, PA 15261, USA
- UPMC Hillman Cancer Center, PA 15213, USA
- College of Pharmacy and Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 03760, South Korea
| | - Namrata Kumar
- UPMC Hillman Cancer Center, PA 15213, USA
- Molecular Genetics and Developmental Biology Graduate Program, University of Pittsburgh School of Medicine, PA 15261, USA
| | - Mathew A Schaich
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, PA 15261, USA
- UPMC Hillman Cancer Center, PA 15213, USA
| | - Zhou Zhong
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, PA 15261, USA
- UPMC Hillman Cancer Center, PA 15213, USA
| | - Barbara van Loon
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), 7491, Trondheim, Norway
| | - Simon C Watkins
- Center for Biologic Imaging, University of Pittsburgh, PA 15261, USA
| | - Bennett Van Houten
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, PA 15261, USA
- UPMC Hillman Cancer Center, PA 15213, USA
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9
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Biechele-Speziale DJ, Sutton TB, Delaney S. Obstacles and opportunities for base excision repair in chromatin. DNA Repair (Amst) 2022; 116:103345. [PMID: 35689883 PMCID: PMC9253077 DOI: 10.1016/j.dnarep.2022.103345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/20/2022] [Accepted: 05/24/2022] [Indexed: 01/01/2023]
Abstract
Most eukaryotic DNA is packaged into chromatin, which is made up of tandemly repeating nucleosomes. This packaging of DNA poses a significant barrier to the various enzymes that must act on DNA, including DNA damage response enzymes that interact intimately with DNA to prevent mutations and cell death. To regulate access to certain DNA regions, chromatin remodeling, variant histone exchange, and histone post-translational modifications have been shown to assist several DNA repair pathways including nucleotide excision repair, single strand break repair, and double strand break repair. While these chromatin-level responses have been directly linked to various DNA repair pathways, how they modulate the base excision repair (BER) pathway remains elusive. This review highlights recent findings that demonstrate how BER is regulated by the packaging of DNA into nucleosome core particles (NCPs) and higher orders of chromatin structures. We also summarize the available data that indicate BER may be enabled by chromatin modifications and remodeling.
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Affiliation(s)
| | | | - Sarah Delaney
- Department of Chemistry, Brown University, Providence, RI, USA.
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10
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Wang L, Xi K, Zhu L, Da LT. DNA Deformation Exerted by Regulatory DNA-Binding Motifs in Human Alkyladenine DNA Glycosylase Promotes Base Flipping. J Chem Inf Model 2022; 62:3213-3226. [PMID: 35708296 DOI: 10.1021/acs.jcim.2c00091] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human alkyladenine DNA glycosylase (AAG) is a key enzyme that corrects a broad range of alkylated and deaminated nucleobases to maintain genomic integrity. When encountering the lesions, AAG adopts a base-flipping strategy to extrude the target base from the DNA duplex to its active site, thereby cleaving the glycosidic bond. Despite its functional importance, the detailed mechanism of such base extrusion and how AAG distinguishes the lesions from an excess of normal bases both remain elusive. Here, through the Markov state model constructed on extensive all-atom molecular dynamics simulations, we find that the alkylated nucleobase (N3-methyladenine, 3MeA) everts through the DNA major groove. Two key AAG motifs, the intercalation and E131-N146 motifs, play active roles in bending/pressing the DNA backbone and widening the DNA minor groove during 3MeA eversion. In particular, the intercalated residue Y162 is involved in buckling the target site at the early stage of 3MeA eversion. Our traveling-salesman based automated path searching algorithm further revealed that a non-target normal adenine tends to be trapped in an exo site near the active site, which however barely exists for a target base 3MeA. Collectively, these results suggest that the Markov state model combined with traveling-salesman based automated path searching acts as a promising approach for studying complex conformational changes of biomolecules and dissecting the elaborate mechanism of target recognition by this unique enzyme.
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Affiliation(s)
- Lingyan Wang
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Kun Xi
- Warshel Institute for Computational Biology, School of Life and Health Sciences, The Chinese University of Hong Kong (Shenzhen), Shenzhen, Guangdong 518172, P. R. China
| | - Lizhe Zhu
- Warshel Institute for Computational Biology, School of Life and Health Sciences, The Chinese University of Hong Kong (Shenzhen), Shenzhen, Guangdong 518172, P. R. China
| | - Lin-Tai Da
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
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11
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Tang S, Stokasimov E, Cui Y, Pellman D. Breakage of cytoplasmic chromosomes by pathological DNA base excision repair. Nature 2022; 606:930-936. [PMID: 35477155 PMCID: PMC10680091 DOI: 10.1038/s41586-022-04767-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 04/15/2022] [Indexed: 12/31/2022]
Abstract
Chromothripsis is a catastrophic mutational process that promotes tumorigenesis and causes congenital disease1-4. Chromothripsis originates from aberrations of nuclei called micronuclei or chromosome bridges5-8. These structures are associated with fragile nuclear envelopes that spontaneously rupture9,10, leading to DNA damage when chromatin is exposed to the interphase cytoplasm. Here we identify a mechanism explaining a major fraction of this DNA damage. Micronuclei accumulate large amounts of RNA-DNA hybrids, which are edited by adenine deaminases acting on RNA (ADAR enzymes) to generate deoxyinosine. Deoxyinosine is then converted into abasic sites by a DNA base excision repair (BER) glycosylase, N-methyl-purine DNA glycosylase11,12 (MPG). These abasic sites are cleaved by the BER endonuclease, apurinic/apyrimidinic endonuclease12 (APE1), creating single-stranded DNA nicks that can be converted to DNA double strand breaks by DNA replication or when closely spaced nicks occur on opposite strands13,14. This model predicts that MPG should be able to remove the deoxyinosine base from the DNA strand of RNA-DNA hybrids, which we demonstrate using purified proteins and oligonucleotide substrates. These findings identify a mechanism for fragmentation of micronuclear chromosomes, an important step in generating chromothripsis. Rather than breaking any normal chromosome, we propose that the eukaryotic cytoplasm only damages chromosomes with pre-existing defects such as the DNA base abnormality described here.
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Affiliation(s)
- Shangming Tang
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Ema Stokasimov
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Yuxiang Cui
- Department of Chemistry, University of California, Riverside, Riverside, CA, USA
| | - David Pellman
- Howard Hughes Medical Institute, Chevy Chase, MD, USA.
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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12
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Muruzabal D, Sanz-Serrano J, Sauvaigo S, Treillard B, Olsen AK, López de Cerain A, Vettorazzi A, Azqueta A. Validation of the in vitro comet assay for DNA cross-links and altered bases detection. Arch Toxicol 2021; 95:2825-2838. [PMID: 34196753 PMCID: PMC8298235 DOI: 10.1007/s00204-021-03102-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/15/2021] [Indexed: 11/27/2022]
Abstract
Mechanistic toxicology is gaining weight for human health risk assessment. Different mechanistic assays are available, such as the comet assay, which detects DNA damage at the level of individual cells. However, the conventional alkaline version only detects strand breaks and alkali-labile sites. We have validated two modifications of the in vitro assay to generate mechanistic information: (1) use of DNA-repair enzymes (i.e., formamidopyrimidine DNA glycosylase, endonuclease III, human 8-oxoguanine DNA glycosylase I and human alkyladenine DNA glycosylase) for detection of oxidized and alkylated bases as well as (2) a modification for detecting cross-links. Seven genotoxicants with different mechanisms of action (potassium bromate, methyl methanesulfonate, ethyl methanesulfonate, hydrogen peroxide, cisplatin, mitomycin C, and benzo[a]pyrene diol epoxide), as well as a non-genotoxic compound (dimethyl sulfoxide) and a cytotoxic compound (Triton X-100) were tested on TK-6 cells. We were able to detect with high sensitivity and clearly differentiate oxidizing, alkylating and cross-linking agents. These modifications of the comet assay significantly increase its sensitivity and its specificity towards DNA lesions, providing mechanistic information regarding the type of damage.
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Affiliation(s)
- Damián Muruzabal
- Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31009, Pamplona, Spain
| | - Julen Sanz-Serrano
- Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31009, Pamplona, Spain
| | - Sylvie Sauvaigo
- LXRepair, Biopolis, 5 Avenue du Grand Sablon, 38700, La Tronche, France
| | | | - Ann-Karin Olsen
- Section of Molecular Toxicology, Department of Environmental Health, Norwegian Institute of Public Health, Skøyen, PO Box 222, 0213, Oslo, Norway
| | - Adela López de Cerain
- Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31009, Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, Pamplona, Spain
| | - Ariane Vettorazzi
- Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31009, Pamplona, Spain.
- IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.
| | - Amaya Azqueta
- Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31009, Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, Pamplona, Spain
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13
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Hans F, Senarisoy M, Bhaskar Naidu C, Timmins J. Focus on DNA Glycosylases-A Set of Tightly Regulated Enzymes with a High Potential as Anticancer Drug Targets. Int J Mol Sci 2020; 21:ijms21239226. [PMID: 33287345 PMCID: PMC7730500 DOI: 10.3390/ijms21239226] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 12/01/2020] [Indexed: 12/25/2022] Open
Abstract
Cancer is the second leading cause of death with tens of millions of people diagnosed with cancer every year around the world. Most radio- and chemotherapies aim to eliminate cancer cells, notably by causing severe damage to the DNA. However, efficient repair of such damage represents a common mechanism of resistance to initially effective cytotoxic agents. Thus, development of new generation anticancer drugs that target DNA repair pathways, and more particularly the base excision repair (BER) pathway that is responsible for removal of damaged bases, is of growing interest. The BER pathway is initiated by a set of enzymes known as DNA glycosylases. Unlike several downstream BER enzymes, DNA glycosylases have so far received little attention and the development of specific inhibitors of these enzymes has been lagging. Yet, dysregulation of DNA glycosylases is also known to play a central role in numerous cancers and at different stages of the disease, and thus inhibiting DNA glycosylases is now considered a valid strategy to eliminate cancer cells. This review provides a detailed overview of the activities of DNA glycosylases in normal and cancer cells, their modes of regulation, and their potential as anticancer drug targets.
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14
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Muruzabal D, Collins A, Azqueta A. The enzyme-modified comet assay: Past, present and future. Food Chem Toxicol 2020; 147:111865. [PMID: 33217526 DOI: 10.1016/j.fct.2020.111865] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 11/08/2020] [Accepted: 11/13/2020] [Indexed: 12/17/2022]
Abstract
The enzyme-modified comet assay was developed in order to detect DNA lesions other than those detected by the standard version (single and double strand breaks and alkali-labile sites). Various lesion-specific enzymes, from the DNA repair machinery of bacteria and humans, have been combined with the comet assay, allowing detection of different oxidized and alkylated bases as well as cyclobutane pyrimidine dimers, mis-incorporated uracil and apurinic/apyrimidinic sites. The enzyme-modified comet assay has been applied in different fields - human biomonitoring, environmental toxicology, and genotoxicity testing (both in vitro and in vivo) - as well as in basic research. Up to now, twelve enzymes have been employed; here we describe the enzymes and give examples of studies in which they have been applied. The bacterial formamidopyrimidine DNA glycosylase (Fpg) and endonuclease III (EndoIII) have been extensively used while others have been used only rarely. Adding further enzymes to the comet assay toolbox could potentially increase the variety of DNA lesions that can be detected. The enzyme-modified comet assay can play a crucial role in the elucidation of the mechanism of action of both direct and indirect genotoxins, thus increasing the value of the assay in the regulatory context.
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Affiliation(s)
- Damián Muruzabal
- Universidad de Navarra, Department of Pharmacology and Toxicology, Faculty of Pharmacy and Nutrition, Irunlarrea 1, 310008, Pamplona, Spain
| | - Andrew Collins
- Department of Nutrition, Institute for Basic Medical Sciences, University of Oslo, Sognsvannsveien 9, 0372, Oslo, Norway
| | - Amaya Azqueta
- Universidad de Navarra, Department of Pharmacology and Toxicology, Faculty of Pharmacy and Nutrition, Irunlarrea 1, 310008, Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.
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15
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Abstract
Genomic DNA is chemically reactive and therefore susceptible to damage by many exogenous and endogenous sources. Lesions produced from these damaging events can have various mutagenic and genotoxic consequences. This Perspective follows the journey of one particular lesion, 1,N6-ethenoadenine (εA), from its formation to replication and repair, and its role in cancerous tissues and inflammatory diseases. εA is generated by the reaction of adenine (A) with vinyl chloride or lipid peroxidation products. We present the miscoding properties of εA with an emphasis on how bacterial and mammalian cells can process lesions differently, leading to varied mutational spectra. But with information from these assays, we can better understand how the miscoding properties of εA lead to biological consequences and how genomic stability can be maintained via DNA repair mechanisms. We discuss how base excision repair (BER) and direct reversal repair (DRR) can minimize the biological consequences of εA lesions. Kinetic parameters of glycosylases and AlkB family enzymes are described, along with a discussion of the relative contributions of the BER and DRR pathways in the repair of εA. Because eukaryotic DNA is packaged in chromatin, we also discuss the impact of this packaging on BER and DRR, specifically in regards to repair of εA. Studying DNA lesions like εA in this context, from origin to biological implications, can provide crucial information to better understand prevention of mutagenesis and cancer.
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Affiliation(s)
- Katelyn L Rioux
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Sarah Delaney
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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16
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Lenz SAP, Li D, Wetmore SD. Insights into the Direct Oxidative Repair of Etheno Lesions: MD and QM/MM Study on the Substrate Scope of ALKBH2 and AlkB. DNA Repair (Amst) 2020; 96:102944. [PMID: 33161373 DOI: 10.1016/j.dnarep.2020.102944] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/27/2020] [Accepted: 07/30/2020] [Indexed: 01/09/2023]
Abstract
E. coli AlkB and human ALKBH2 belong to the AlkB family enzymes, which contain several α-ketoglutarate (α-KG)/Fe(II)-dependent dioxygenases that repair alkylated DNA. Specifically, the AlkB enzymes catalyze decarboxylation of α-KG to generate a high-valent Fe(IV)-oxo species that oxidizes alkyl groups on DNA adducts. AlkB and ALKBH2 have been reported to differentially repair select etheno adducts, with preferences for 1,N6-ethenoadenine (1,N6-εA) and 3,N4-ethenocytosine (3,N4-εC) over 1,N2-ethenoguanine (1,N2-εG). However, N2,3-ethenoguanine (N2,3-εG), the most common etheno adduct, is not repaired by the AlkB enzymes. Unfortunately, a structural understanding of the differential activity of E. coli AlkB and human ALKBH2 is lacking due to challenges acquiring atomistic details for a range of substrates using experiments. This study uses both molecular dynamics (MD) simulations and ONIOM(QM:MM) calculations to determine how the active site changes upon binding each etheno adduct and characterizes the corresponding catalytic impacts. Our data reveal that the preferred etheno substrates (1,N6-εA and 3,N4-εC) form favorable interactions with catalytic residues that situate the lesion near the Fe(IV)-oxo species and permit efficient oxidation. In contrast, although the damage remains correctly aligned with respect to the Fe(IV)-oxo moiety, repair of 1,N2-εG is mitigated by increased solvation of the active site and a larger distance between Fe(IV)-oxo and the aberrant carbons. Binding of non-substrate N2,3-εG in the active site disrupts key DNA-enzyme interactions, and positions the aberrant carbon atoms even further from the Fe(IV)-oxo species, leading to prohibitively high barriers for oxidative catalysis. Overall, our calculations provide the first structural insight required to rationalize the experimentally-reported substrate specificities of AlkB and ALKBH2 and thereby highlight the roles of several active site residues in the repair of etheno adducts that directly correlates with available experimental data. These proposed catalytic strategies can likely be generalized to other α-KG/Fe(II)-dependent dioxygenases that play similar critical biological roles, including epigenetic and post-translational regulation.
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Affiliation(s)
- Stefan A P Lenz
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada
| | - Deyu Li
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, 02881, USA
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada.
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17
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Pinthong N, Limudomporn P, Vasuvat J, Adisakwattana P, Rattaprasert P, Chavalitshewinkoon-Petmitr P. Molecular characterization of Plasmodium falciparum DNA-3-methyladenine glycosylase. Malar J 2020; 19:284. [PMID: 32762689 PMCID: PMC7409487 DOI: 10.1186/s12936-020-03355-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 07/28/2020] [Indexed: 11/10/2022] Open
Abstract
Background The emergence of artemisinin-resistant malaria parasites highlights the need for novel drugs and their targets. Alkylation of purine bases can hinder DNA replication and if unresolved would eventually result in cell death. DNA-3-methyladenine glycosylase (MAG) is responsible for the repair of those alkylated bases. Plasmodium falciparum (Pf) MAG was characterized for its potential for development as an anti-malarial candidate. Methods Native PfMAG from crude extract of chloroquine- and pyrimethamine-resistant P. falciparum K1 strain was partially purified using three chromatographic procedures. From bio-informatics analysis, primers were designed for amplification, insertion into pBAD202/D-TOPO and heterologous expression in Escherichia coli of recombinant PfMAG. Functional and biochemical properties of the recombinant enzyme were characterized. Results PfMAG activity was most prominent in parasite schizont stages, with a specific activity of 147 U/mg (partially purified) protein. K1 PfMAG contained an insertion of AAT (coding for asparagine) compared to 3D7 strain and 16% similarity to the human enzyme. Recombinant PfMAG (74 kDa) was twice as large as the human enzyme, preferred double-stranded DNA substrate, and demonstrated glycosylase activity over a pH range of 4–9, optimal salt concentration of 100–200 mM NaCl but reduced activity at 250 mM NaCl, no requirement for divalent cations, which were inhibitory in a dose-dependent manner. Conclusion PfMAG activity increased with parasite development being highest in the schizont stages. K1 PfMAG contained an indel AAT (asparagine) not present in 3D7 strain and the recombinant enzyme was twice as large as the human enzyme. Recombinant PfMAG had a wide range of optimal pH activity, and was inhibited at high (250 mM) NaCl concentration as well as by divalent cations. The properties of PfMAG provide basic data that should be of assistance in developing anti-malarials against this potential parasite target.
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Affiliation(s)
- Nattapon Pinthong
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Paviga Limudomporn
- Department of Zoology, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Jitlada Vasuvat
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Poom Adisakwattana
- Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Pongruj Rattaprasert
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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Muruzabal D, Sanz-Serrano J, Sauvaigo S, Gützkow KB, López de Cerain A, Vettorazzi A, Azqueta A. Novel approach for the detection of alkylated bases using the enzyme-modified comet assay. Toxicol Lett 2020; 330:108-117. [PMID: 32380118 DOI: 10.1016/j.toxlet.2020.04.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/06/2020] [Accepted: 04/24/2020] [Indexed: 12/26/2022]
Abstract
The enzyme-modified comet assay is widely used for the detection of oxidized DNA lesions. Here we describe for the first time the use of the human alkyladenine DNA glycosylase (hAAG) for the detection of alkylated bases. hAAG was titrated using untreated and methyl methanesulfonate (MMS)-treated TK-6 cells. The hAAG-modified comet assay was compared to the formamidopyrimidine DNA glycosylase (Fpg)-modified comet assay, widely used to detect oxidized lesions but that also detects ring-opened purines derived from some alkylated lesions, using cells treated with potassium bromate (oxidizing agent) or MMS. Moreover, neutral and alkaline lysis conditions were used to determine the nature of detected lesions. When alkaline lysis was employed (condition normally used), the level of hAAG-sensitive sites was higher than the Fpg-sensitive sites in MMS-treated cells and hAAG, unlike Fpg, did not detect oxidized bases. After neutral lysis, Fpg did not detect MMS-induced lesions; however, results obtained with hAAG remained unchanged. As expected, Fpg detected oxidized purines and imidazole ring-opened purines, derived from N7-methylguanines under alkaline conditions. It seems that hAAG detected N7-methylguanines, the ring-opened purines derived at high pH, and 3-methlyladenines. Specificity of hAAG towards different DNA lesions was evaluated using a multiplex oligonucleotide-cleavage assay, confirming the ability of hAAG to detect ethenoadenines and hypoxanthine. The hAAG-modified comet assay is a new tool for the detection of alkylated bases.
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Affiliation(s)
- Damián Muruzabal
- Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31009 Pamplona, Spain
| | - Julen Sanz-Serrano
- Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31009 Pamplona, Spain
| | - Sylvie Sauvaigo
- LXRepair, Biopolis, 5 avenue du Grand Sablon, 38700 La Tronche, France
| | - Kristine B Gützkow
- Section of Molecular Toxicology, Department of Environmental Health, Norwegian Institute of Public Health, P.O. Box 222, Skøyen, 0213 Oslo, Norway
| | - Adela López de Cerain
- Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31009 Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Spain
| | - Ariane Vettorazzi
- Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31009 Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Spain
| | - Amaya Azqueta
- Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31009 Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Spain.
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19
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Thelen AZ, O'Brien PJ. Recognition of 1, N2-ethenoguanine by alkyladenine DNA glycosylase is restricted by a conserved active-site residue. J Biol Chem 2020; 295:1685-1693. [PMID: 31882538 PMCID: PMC7008384 DOI: 10.1074/jbc.ra119.011459] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/19/2019] [Indexed: 12/30/2022] Open
Abstract
The adenine, cytosine, and guanine bases of DNA are susceptible to alkylation by the aldehyde products of lipid peroxidation and by the metabolic byproducts of vinyl chloride pollutants. The resulting adducts spontaneously cyclize to form harmful etheno lesions. Cells employ a variety of DNA repair pathways to protect themselves from these pro-mutagenic modifications. Human alkyladenine DNA glycosylase (AAG) is thought to initiate base excision repair of both 1,N6-ethenoadenine (ϵA) and 1,N2-ethenoguanine (ϵG). However, it is not clear how AAG might accommodate ϵG in an active site that is complementary to ϵA. This prompted a thorough investigation of AAG-catalyzed excision of ϵG from several relevant contexts. Using single-turnover and multiple-turnover kinetic analyses, we found that ϵG in its natural ϵG·C context is very poorly recognized relative to ϵA·T. Bulged and mispaired ϵG contexts, which can form during DNA replication, were similarly poor substrates for AAG. Furthermore, AAG could not recognize an ϵG site in competition with excess undamaged DNA sites. Guided by previous structural studies, we hypothesized that Asn-169, a conserved residue in the AAG active-site pocket, contributes to discrimination against ϵG. Consistent with this model, the N169S variant of AAG was 7-fold more active for excision of ϵG compared with the wildtype (WT) enzyme. Taken together, these findings suggest that ϵG is not a primary substrate of AAG, and that current models for etheno lesion repair in humans should be revised. We propose that other repair and tolerance mechanisms operate in the case of ϵG lesions.
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Affiliation(s)
- Adam Z Thelen
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0600
| | - Patrick J O'Brien
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0600.
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20
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Attia SM, Al-Hamamah MA, Ahmad SF, Nadeem A, Attia MSM, Ansari MA, Bakheet SA, Al-Ayadhi LY. Evaluation of DNA repair efficiency in autistic children by molecular cytogenetic analysis and transcriptome profiling. DNA Repair (Amst) 2019; 85:102750. [PMID: 31765876 DOI: 10.1016/j.dnarep.2019.102750] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 09/02/2019] [Accepted: 11/12/2019] [Indexed: 12/13/2022]
Abstract
Data regarding DNA repair perturbations in autism, which might increase the risk of malignancy, are scarce. To evaluate whether DNA repair may be disrupted in autistic children, we assessed the incidence of endogenous basal DNA strand breaks as well as the efficiency of repairing DNA damage caused by γ-ray in lymphocytes isolated from autistic and healthy children. The incidence of DNA damage and the kinetics of DNA repair were determined by comet assay, while the incidence of residual DNA damage was evaluated by structural chromosomal aberration analysis. Transcriptome profiling of 84 genes associated with DNA damage and repair-signaling pathways was performed by RT² Profiler PCR Array. The array data were confirmed by RT-PCR and western blot studies. Our data indicate that the incidence of basal oxidative DNA strand breaks in autistic children was greater than that in nonautistic controls. Lymphocytes from autistic children displayed higher susceptibility to damage by γ-irradiation and slower repair rate than those from nonautistic children. Although the total unstable chromosomal aberrations were unaffected, lymphocytes from autistic children were more susceptible to chromosomal damage caused by γ-ray than those from nonautistic children. Transcriptomic analysis revealed that several genes associated with repair were downregulated in lymphocytes from autistic individuals and in those exposed to γ-irradiation. This may explain the increased oxidative DNA damage and reduced repair rate in lymphocytes from autistic individuals. These features may be related to the possible correlation between autism and the elevated risk of cancer and may explain the role of the disruption of the DNA repair process in the pathogenesis of autism.
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Affiliation(s)
- Sabry M Attia
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia; Department of Pharmacology and Toxicology, College of Pharmacy, Al-Azhar University, Cairo, Egypt.
| | - Mohammed A Al-Hamamah
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Sheikh F Ahmad
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Ahmed Nadeem
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | | | - Mushtaq A Ansari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Saleh A Bakheet
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Laila Y Al-Ayadhi
- Autism Research and Treatment Center, AL-Amodi Autism Research Chair, Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
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21
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Petri net-based model of the human DNA base excision repair pathway. PLoS One 2019; 14:e0217913. [PMID: 31518347 PMCID: PMC6743755 DOI: 10.1371/journal.pone.0217913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 05/21/2019] [Indexed: 12/14/2022] Open
Abstract
Cellular DNA is daily exposed to several damaging agents causing a plethora of DNA lesions. As a first aid to restore DNA integrity, several enzymes got specialized in damage recognition and lesion removal during the process called base excision repair (BER). A large number of DNA damage types and several different readers of nucleic acids lesions during BER pathway as well as two sub-pathways were considered in the definition of a model using the Petri net framework. The intuitive graphical representation in combination with precise mathematical analysis methods are the strong advantages of the Petri net-based representation of biological processes and make Petri nets a promising approach for modeling and analysis of human BER. The reported results provide new information that will aid efforts to characterize in silico knockouts as well as help to predict the sensitivity of the cell with inactivated repair proteins to different types of DNA damage. The results can also help in identifying the by-passing pathways that may lead to lack of pronounced phenotypes associated with mutations in some of the proteins. This knowledge is very useful when DNA damage-inducing drugs are introduced for cancer therapy, and lack of DNA repair is desirable for tumor cell death.
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22
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Kennedy EE, Li C, Delaney S. Global Repair Profile of Human Alkyladenine DNA Glycosylase on Nucleosomes Reveals DNA Packaging Effects. ACS Chem Biol 2019; 14:1687-1692. [PMID: 31310499 DOI: 10.1021/acschembio.9b00263] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Alkyladenine DNA glycosylase (AAG) is the only known human glycosylase capable of excising alkylated purines from DNA, including the highly mutagenic 1,N6-ethenoadenine (εA) lesion. Here, we examine the ability of AAG to excise εA from a nucleosome core particle (NCP), which is the primary repeating unit of DNA packaging in eukaryotes. Using chemical synthesis techniques, we assembled a global population of NCPs in which A is replaced with εA. While each NCP contains no more than one εA lesion, the total population contains εA in 49 distinct geometric positions. Using this global εA-containing NCP system, we obtained kinetic parameters of AAG throughout the NCP architecture. We observed monophasic reaction kinetics across the NCP, but varying amounts of AAG excision. AAG activity is correlated with solution accessibility and local histone architecture. Notably, we identified some highly solution-accessible lesions that are not repaired well, and an increase in repair within the region of asymmetric unwrapping of the nucleosomal DNA end. These observations support in vivo work and provide molecular-level insight into the relationship between repair and NCP architecture.
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Affiliation(s)
- Erin E. Kennedy
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Chuxuan Li
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Sarah Delaney
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02912, United States
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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23
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Wang LJ, Luo ML, Yang XY, Li XF, Wu Y, Zhang CY. Controllable Autocatalytic Cleavage-Mediated Fluorescence Recovery for Homogeneous Sensing of Alkyladenine DNA Glycosylase from Human Cancer Cells. Am J Cancer Res 2019; 9:4450-4460. [PMID: 31285772 PMCID: PMC6599653 DOI: 10.7150/thno.35393] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 05/17/2019] [Indexed: 11/24/2022] Open
Abstract
DNA alkylation and oxidation are two most common forms of cytotoxic damage with the characteristics of mutagenic and carcinogenic. Human alkyladenine DNA glycosylase (hAAG) is the only glycosylase known to repair a wide variety of alkylative and oxidative DNA lesions. However, few approaches are capable of real-time monitoring hAAG activity. Methods: Herein, we develop a facile fluorescent strategy for homogeneous and sensitive sensing of hAAG activity based on the controllable autocatalytic cleavage-mediated fluorescence recovery. The presence of hAAG enables the cleavage of hairpin probe 1 (HP1) at the damaged 2′-deoxyinosine site by AP endonuclease 1 (APE1), forming a DNA duplex. The trigger 1 built in the resultant DNA duplex may hybridize with hairpin probe 2 (HP2) to induce the T7 exonuclease (T7 exo)-catalyzed recycling cleavage of HP2 (Cycle I) to release trigger 2. The trigger 2 can further hybridize with the signal probe (a fluorophore (FAM) and a quencher (BHQ1) modified at its 5′ and 3′ ends) to induce the subsequent recycling cleavage of signal probes (Cycle II) to liberate FAM molecules. Through two-recycling autocatalytic cleavage processes, large amounts of fluorophore molecules (i.e., FAM) are liberated from the FAM-BHQ1 fluorescence resonance energy transfer (FRET) pair, leading to the amplified fluorescence recovery. Results: Taking advantage of the high accuracy of in vivo DNA repair mechanism, the high specificity of T7 exo-catalyzed mononucleotides hydrolysis, and the high efficiency of autocatalytic recycling amplification, this strategy exhibits high sensitivity with a detection limit of 4.9 × 10-6 U/μL and a large dynamic range of 4 orders of magnitude from 1 × 10-5 to 0.1 U/μL, and it can further accurately evaluate the enzyme kinetic parameters, screen the potential inhibitors, and even quantify the hAAG activity from 1 cancer cell. Conclusion: The proposed strategy can provide a facile and universal platform for the monitoring of DNA damage-related repair enzymes, holding great potential for DNA repair-related biochemical research, clinical diagnosis, drug discovery, and cancer therapy.
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24
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Allocca M, Corrigan JJ, Mazumder A, Fake KR, Samson LD. Inflammation, necrosis, and the kinase RIP3 are key mediators of AAG-dependent alkylation-induced retinal degeneration. Sci Signal 2019; 12:12/568/eaau9216. [PMID: 30755477 DOI: 10.1126/scisignal.aau9216] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
DNA-alkylating agents are commonly used to kill cancer cells, but the base excision repair (BER) pathway they trigger can also produce toxic intermediates that cause tissue damage, such as retinal degeneration (RD). Apoptosis, a process of programmed cell death, is assumed to be the main mechanism of this alkylation-induced photoreceptor (PR) cell death in RD. Here, we studied the involvement of necroptosis (another programmed cell death process) and inflammation in alkylation-induced RD. Male mice exposed to a methylating agent exhibited a reduced number of PR cell rows, active gliosis, and cytokine induction and macrophage infiltration in the retina. Dying PRs exhibited a necrotic morphology, increased 8-hydroxyguanosine abundance (an oxidative damage marker), and overexpression of the necroptosis-associated genes Rip1 and Rip3 The activity of PARP1, which mediates BER, cell death, and inflammation, was increased in PR cells and associated with the release of proinflammatory chemokine HMGB1 from PR nuclei. Mice lacking the anti-inflammatory cytokine IL-10 exhibited more severe RD, whereas deficiency of RIP3 (also known as RIPK3) conferred partial protection. Female mice were partially protected from alkylation-induced RD, showing reduced necroptosis and inflammation compared to males. PRs in mice lacking the BER-initiating DNA glycosylase AAG did not exhibit alkylation-induced necroptosis or inflammation. Our findings show that AAG-initiated BER at alkylated DNA bases induces sex-dependent RD primarily by triggering necroptosis and activating an inflammatory response that amplifies the original damage and, furthermore, reveal new potential targets to prevent this side effect of chemotherapy.
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Affiliation(s)
- Mariacarmela Allocca
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Joshua J Corrigan
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Aprotim Mazumder
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Kimberly R Fake
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Leona D Samson
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA. .,Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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25
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Tang Y, Wang Z, Li M, Zhang R, Zhang J. Simultaneous quantitation of 14 DNA alkylation adducts in human liver and kidney cells by UHPLC-MS/MS: Application to profiling DNA adducts of genotoxic reagents. J Pharm Biomed Anal 2019; 166:387-397. [PMID: 30711808 DOI: 10.1016/j.jpba.2019.01.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 01/04/2023]
Abstract
A rapid, sensitive and wide coverage ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method has been developed and validated for the simultaneous quantitation of 14 alkylation DNA adducts in cell genomic DNA, RNA and cell contents isolated from the in vitro cultured human kidney cell line 293 T and the human liver cell line L02 exposed to 3 genotoxic reagents: N-methyl-N-nitrosourea (MNU), methyl methanesulfonate (MMS) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). After exposure, DNA was isolated and directly hydrolysed under acid conditions or digested by enzymes to obtain the hydrolysates containing DNA alkylation adducts followed by optimization of the pretreatment method and chromatographic separation conditions. Quantification was performed on a Waters ACQUITY UPLC BEH Amide column (1.7 μm, 2.1 × 150 mm) using an electrospray ionization (ESI) source in positive mode by selective reaction monitoring (SRM) at the precursor to product ion transitions of 14 analytes. The method showed selectivity, good linearity (r>0.9950), accuracy (82.1%-115%), and intra-day (RSD%<14%) and inter-day (RSD%<15%) precision for 14 analytes. The recoveries of two pretreatment methods were all more than 50.5%, and no relative matrix effects were observed. Additionally, the samples were stable after short-term storage at 20 ℃ for 2 h, at 4 ℃ for 48 h or one cycle of freeze-thaw at -80 ℃. The established UHPLC-MS/MS method was used to evaluate the changes in alkylation DNA adducts and epigenetic modification-related methylcytosine after exposure to genotoxic reagents. For the first time, the results demonstrated that 3 genotoxic reagents induced different total amounts of adducts in the following sequence: MMS > NNK > MNU, and showed significant differences in the ratios of 7MeG to 1MeA and 1MeG to 1MeA in the 293 T cell model. Meanwhile, 293 T and L02 cells revealed significantly different DNA adduct formation characteristics in the contents of 1MeG and 1MeA. The DNA adduct formation relationships between DNA, RNA, and cell contents were probed to predict cancer risk and potential genotoxic exposure. This approach could be used to investigate the DNA adducts, their formation and the relationship to the mutagenicity or carcinogenicity of genotoxic reagents in future studies.
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Affiliation(s)
- Yu Tang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Zhe Wang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Menglin Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Ruiping Zhang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Jinlan Zhang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China.
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26
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Li J, Svilar D, McClellan S, Kim JH, Ahn EYE, Vens C, Wilson DM, Sobol RW. DNA Repair Molecular Beacon assay: a platform for real-time functional analysis of cellular DNA repair capacity. Oncotarget 2018; 9:31719-31743. [PMID: 30167090 PMCID: PMC6114979 DOI: 10.18632/oncotarget.25859] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 07/12/2018] [Indexed: 12/15/2022] Open
Abstract
Numerous studies have shown that select DNA repair enzyme activities impact response and/or toxicity of genotoxins, suggesting a requirement for enzyme functional analyses to bolster precision medicine or prevention. To address this need, we developed a DNA Repair Molecular Beacon (DRMB) platform that rapidly measures DNA repair enzyme activity in real-time. The DRMB assay is applicable for discovery of DNA repair enzyme inhibitors, for the quantification of enzyme rates and is sufficiently sensitive to differentiate cellular enzymatic activity that stems from variation in expression or effects of amino acid substitutions. We show activity measures of several different base excision repair (BER) enzymes, including proteins with tumor-identified point mutations, revealing lesion-, lesion-context- and cell-type-specific repair dependence; suggesting application for DNA repair capacity analysis of tumors. DRMB measurements using lysates from isogenic control and APE1-deficient human cells suggests the major mechanism of base lesion removal by most DNA glycosylases may be mono-functional base hydrolysis. In addition, development of a microbead-conjugated DRMB assay amenable to flow cytometric analysis further advances its application. Our studies establish an analytical platform capable of evaluating the enzyme activity of select DNA repair proteins in an effort to design and guide inhibitor development and precision cancer therapy options.
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Affiliation(s)
- Jianfeng Li
- University of South Alabama Mitchell Cancer Institute, Mobile, AL, USA
| | - David Svilar
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, PA, USA
| | - Steven McClellan
- University of South Alabama Mitchell Cancer Institute, Mobile, AL, USA
| | - Jung-Hyun Kim
- University of South Alabama Mitchell Cancer Institute, Mobile, AL, USA
| | | | - Conchita Vens
- The Netherlands Cancer Institute, Division of Cell Biology, Amsterdam, The Netherlands
| | - David M Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging, IRP, NIH Baltimore, MD, USA
| | - Robert W Sobol
- University of South Alabama Mitchell Cancer Institute, Mobile, AL, USA.,Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, PA, USA
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27
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Kladova OA, Bazlekowa-Karaban M, Baconnais S, Piétrement O, Ishchenko AA, Matkarimov BT, Iakovlev DA, Vasenko A, Fedorova OS, Le Cam E, Tudek B, Kuznetsov NA, Saparbaev M. The role of the N-terminal domain of human apurinic/apyrimidinic endonuclease 1, APE1, in DNA glycosylase stimulation. DNA Repair (Amst) 2018; 64:10-25. [PMID: 29475157 DOI: 10.1016/j.dnarep.2018.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 01/09/2018] [Accepted: 02/06/2018] [Indexed: 12/25/2022]
Abstract
The base excision repair (BER) pathway consists of sequential action of DNA glycosylase and apurinic/apyrimidinic (AP) endonuclease necessary to remove a damaged base and generate a single-strand break in duplex DNA. Human multifunctional AP endonuclease 1 (APE1, a.k.a. APEX1, HAP-1, or Ref-1) plays essential roles in BER by acting downstream of DNA glycosylases to incise a DNA duplex at AP sites and remove 3'-blocking sugar moieties at DNA strand breaks. Human 8-oxoguanine-DNA glycosylase (OGG1), methyl-CpG-binding domain 4 (MBD4, a.k.a. MED1), and alkyl-N-purine-DNA glycosylase (ANPG, a.k.a. Aag or MPG) excise a variety of damaged bases from DNA. Here we demonstrated that the redox-deficient truncated APE1 protein lacking the first N-terminal 61 amino acid residues (APE1-NΔ61) cannot stimulate DNA glycosylase activities of OGG1, MBD4, and ANPG on duplex DNA substrates. Electron microscopy imaging of APE1-DNA complexes revealed oligomerization of APE1 along the DNA duplex and APE1-mediated DNA bridging followed by DNA aggregation. APE1 polymerizes on both undamaged and damaged DNA in cooperative mode. Association of APE1 with undamaged DNA may enable scanning for damage; however, this event reduces effective concentration of the enzyme and subsequently decreases APE1-catalyzed cleavage rates on long DNA substrates. We propose that APE1 oligomers on DNA induce helix distortions thereby enhancing molecular recognition of DNA lesions by DNA glycosylases via a conformational proofreading/selection mechanism. Thus, APE1-mediated structural deformations of the DNA helix stabilize the enzyme-substrate complex and promote dissociation of human DNA glycosylases from the AP site with a subsequent increase in their turnover rate. SIGNIFICANCE STATEMENT The major human apurinic/apyrimidinic (AP) endonuclease, APE1, stimulates DNA glycosylases by increasing their turnover rate on duplex DNA substrates. At present, the mechanism of the stimulation remains unclear. We report that the redox domain of APE1 is necessary for the active mode of stimulation of DNA glycosylases. Electron microscopy revealed that full-length APE1 oligomerizes on DNA possibly via cooperative binding to DNA. Consequently, APE1 shows DNA length dependence with preferential repair of short DNA duplexes. We propose that APE1-catalyzed oligomerization along DNA induces helix distortions, which in turn enable conformational selection and stimulation of DNA glycosylases. This new biochemical property of APE1 sheds light on the mechanism of redox function and its role in DNA repair.
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Affiliation(s)
- Olga A Kladova
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk 630090, Russia
| | - Milena Bazlekowa-Karaban
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland; Groupe «Réparation de l'ADN», Equipe Labellisée par la Ligue Nationale contre le Cancer, CNRS UMR8200, Université Paris-Sud, Gustave Roussy Cancer Campus, F-94805 Villejuif Cedex, France; Institute of Genetics and Biotechnology, University of Warsaw, Warsaw, Poland
| | - Sonia Baconnais
- CNRS UMR8126, Université Paris-Sud, Université Paris-Saclay, Gustave Roussy, F-94805 Villejuif Cedex, France
| | - Olivier Piétrement
- CNRS UMR8126, Université Paris-Sud, Université Paris-Saclay, Gustave Roussy, F-94805 Villejuif Cedex, France
| | - Alexander A Ishchenko
- Groupe «Réparation de l'ADN», Equipe Labellisée par la Ligue Nationale contre le Cancer, CNRS UMR8200, Université Paris-Sud, Gustave Roussy Cancer Campus, F-94805 Villejuif Cedex, France
| | - Bakhyt T Matkarimov
- National laboratory Astana, Nazarbayev University, Astana 010000, Kazakhstan
| | - Danila A Iakovlev
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk 630090, Russia
| | - Andrey Vasenko
- National Research University Higher School of Economics, 101000 Moscow, Russia
| | - Olga S Fedorova
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk 630090, Russia
| | - Eric Le Cam
- CNRS UMR8126, Université Paris-Sud, Université Paris-Saclay, Gustave Roussy, F-94805 Villejuif Cedex, France
| | - Barbara Tudek
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland; Institute of Genetics and Biotechnology, University of Warsaw, Warsaw, Poland
| | - Nikita A Kuznetsov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk 630090, Russia.
| | - Murat Saparbaev
- Groupe «Réparation de l'ADN», Equipe Labellisée par la Ligue Nationale contre le Cancer, CNRS UMR8200, Université Paris-Sud, Gustave Roussy Cancer Campus, F-94805 Villejuif Cedex, France.
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28
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Yu AM, Calvo JA, Muthupalani S, Samson LD. The Mbd4 DNA glycosylase protects mice from inflammation-driven colon cancer and tissue injury. Oncotarget 2017; 7:28624-36. [PMID: 27086921 PMCID: PMC5053750 DOI: 10.18632/oncotarget.8721] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 03/28/2016] [Indexed: 12/12/2022] Open
Abstract
Much of the global cancer burden is associated with longstanding inflammation accompanied by release of DNA-damaging reactive oxygen and nitrogen species. Here, we report that the Mbd4 DNA glycosylase is protective in the azoxymethane/dextran sodium sulfate (AOM/DSS) mouse model of inflammation-driven colon cancer. Mbd4 excises T and U from T:G and U:G mismatches caused by deamination of 5-methylcytosine and cytosine. Since the rate of deamination is higher in inflamed tissues, we investigated the role of Mbd4 in inflammation-driven tumorigenesis. In the AOM/DSS assay, Mbd4-/- mice displayed more severe clinical symptoms, decreased survival, and a greater tumor burden than wild-type (WT) controls. The increased tumor burden in Mbd4-/- mice did not arise from impairment of AOM-induced apoptosis in the intestinal crypt. Histopathological analysis indicated that the colonic epithelium of Mbd4-/- mice is more vulnerable than WT to DSS-induced tissue damage. We investigated the role of the Mbd4-/- immune system in AOM/DSS-mediated carcinogenesis by repeating the assay on WT and Mbd4-/- mice transplanted with WT bone marrow. Mbd4-/- mice with WT bone marrow behaved similarly to Mbd4-/- mice. Together, our results indicate that the colonic epithelium of Mbd4-/- mice is more vulnerable to DSS-induced injury, which exacerbates inflammation-driven tissue injury and cancer.
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Affiliation(s)
- Amy Marie Yu
- Biological Engineering Department, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA
| | - Jennifer A Calvo
- Biological Engineering Department, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA.,Biology Department, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA
| | - Suresh Muthupalani
- Department of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA
| | - Leona D Samson
- Biological Engineering Department, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA.,Biology Department, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA
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29
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In vivo measurements of interindividual differences in DNA glycosylases and APE1 activities. Proc Natl Acad Sci U S A 2017; 114:E10379-E10388. [PMID: 29122935 DOI: 10.1073/pnas.1712032114] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The integrity of our DNA is challenged with at least 100,000 lesions per cell on a daily basis. Failure to repair DNA damage efficiently can lead to cancer, immunodeficiency, and neurodegenerative disease. Base excision repair (BER) recognizes and repairs minimally helix-distorting DNA base lesions induced by both endogenous and exogenous DNA damaging agents. Levels of BER-initiating DNA glycosylases can vary between individuals, suggesting that quantitating and understanding interindividual differences in DNA repair capacity (DRC) may enable us to predict and prevent disease in a personalized manner. However, population studies of BER capacity have been limited because most methods used to measure BER activity are cumbersome, time consuming and, for the most part, only allow for the analysis of one DNA glycosylase at a time. We have developed a fluorescence-based multiplex flow-cytometric host cell reactivation assay wherein the activity of several enzymes [four BER-initiating DNA glycosylases and the downstream processing apurinic/apyrimidinic endonuclease 1 (APE1)] can be tested simultaneously, at single-cell resolution, in vivo. Taking advantage of the transcriptional properties of several DNA lesions, we have engineered specific fluorescent reporter plasmids for quantitative measurements of 8-oxoguanine DNA glycosylase, alkyl-adenine DNA glycosylase, MutY DNA glycosylase, uracil DNA glycosylase, and APE1 activity. We have used these reporters to measure differences in BER capacity across a panel of cell lines collected from healthy individuals, and to generate mathematical models that predict cellular sensitivity to methylmethane sulfonate, H2O2, and 5-FU from DRC. Moreover, we demonstrate the suitability of these reporters to measure differences in DRC in multiple pathways using primary lymphocytes from two individuals.
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30
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Chaim IA, Gardner A, Wu J, Iyama T, Wilson DM, Samson LD. A novel role for transcription-coupled nucleotide excision repair for the in vivo repair of 3,N4-ethenocytosine. Nucleic Acids Res 2017; 45:3242-3252. [PMID: 28115629 PMCID: PMC5389632 DOI: 10.1093/nar/gkx015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 01/20/2017] [Indexed: 12/13/2022] Open
Abstract
Etheno (ε) DNA base adducts are highly mutagenic lesions produced endogenously via reactions with lipid peroxidation (LPO) products. Cancer-promoting conditions, such as inflammation, can induce persistent oxidative stress and increased LPO, resulting in the accumulation of ε-adducts in different tissues. Using a recently described fluorescence multiplexed host cell reactivation assay, we show that a plasmid reporter bearing a site-specific 3,N4-ethenocytosine (εC) causes transcriptional blockage. Notably, this blockage is exacerbated in Cockayne Syndrome and xeroderma pigmentosum patient-derived lymphoblastoid and fibroblast cells. Parallel RNA-Seq expression analysis of the plasmid reporter identifies novel transcriptional mutagenesis properties of εC. Our studies reveal that beyond the known pathways, such as base excision repair, the process of transcription-coupled nucleotide excision repair plays a role in the removal of εC from the genome, and thus in the protection of cells and tissues from collateral damage induced by inflammatory responses.
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Affiliation(s)
- Isaac A Chaim
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Alycia Gardner
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jie Wu
- The Barbara K. Ostrom (1978) Bioinformatics and Computing Facility in the Swanson Biotechnology Center, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Teruaki Iyama
- Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224, USA
| | - David M Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224, USA
| | - Leona D Samson
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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31
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Yang Z, Nejad MI, Varela JG, Price NE, Wang Y, Gates KS. A role for the base excision repair enzyme NEIL3 in replication-dependent repair of interstrand DNA cross-links derived from psoralen and abasic sites. DNA Repair (Amst) 2017; 52:1-11. [PMID: 28262582 PMCID: PMC5424475 DOI: 10.1016/j.dnarep.2017.02.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 02/13/2017] [Indexed: 12/23/2022]
Abstract
Interstrand DNA-DNA cross-links are highly toxic lesions that are important in medicinal chemistry, toxicology, and endogenous biology. In current models of replication-dependent repair, stalling of a replication fork activates the Fanconi anemia pathway and cross-links are "unhooked" by the action of structure-specific endonucleases such as XPF-ERCC1 that make incisions flanking the cross-link. This process generates a double-strand break, which must be subsequently repaired by homologous recombination. Recent work provided evidence for a new, incision-independent unhooking mechanism involving intrusion of a base excision repair (BER) enzyme, NEIL3, into the world of cross-link repair. The evidence suggests that the glycosylase action of NEIL3 unhooks interstrand cross-links derived from an abasic site or the psoralen derivative trioxsalen. If the incision-independent NEIL3 pathway is blocked, repair reverts to the incision-dependent route. In light of the new model invoking participation of NEIL3 in cross-link repair, we consider the possibility that various BER glycosylases or other DNA-processing enzymes might participate in the unhooking of chemically diverse interstrand DNA cross-links.
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Affiliation(s)
- Zhiyu Yang
- University of Missouri Department of Chemistry, 125 Chemistry Building Columbia, MO 65211, United States
| | - Maryam Imani Nejad
- University of Missouri Department of Chemistry, 125 Chemistry Building Columbia, MO 65211, United States
| | - Jacqueline Gamboa Varela
- University of Missouri Department of Chemistry, 125 Chemistry Building Columbia, MO 65211, United States
| | - Nathan E Price
- University of California-Riverside, Department of Chemistry, 501 Big Springs Road Riverside, CA 92521-0403, United States
| | - Yinsheng Wang
- University of California-Riverside, Department of Chemistry, 501 Big Springs Road Riverside, CA 92521-0403, United States
| | - Kent S Gates
- University of Missouri Department of Chemistry, 125 Chemistry Building Columbia, MO 65211, United States; University of Missouri Department of Biochemistry, 125 Chemistry Building Columbia, MO 65211, United States.
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32
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Whitaker AM, Schaich MA, Smith MR, Flynn TS, Freudenthal BD. Base excision repair of oxidative DNA damage: from mechanism to disease. Front Biosci (Landmark Ed) 2017; 22:1493-1522. [PMID: 28199214 DOI: 10.2741/4555] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Reactive oxygen species continuously assault the structure of DNA resulting in oxidation and fragmentation of the nucleobases. Both oxidative DNA damage itself and its repair mediate the progression of many prevalent human maladies. The major pathway tasked with removal of oxidative DNA damage, and hence maintaining genomic integrity, is base excision repair (BER). The aphorism that structure often dictates function has proven true, as numerous recent structural biology studies have aided in clarifying the molecular mechanisms used by key BER enzymes during the repair of damaged DNA. This review focuses on the mechanistic details of the individual BER enzymes and the association of these enzymes during the development and progression of human diseases, including cancer and neurological diseases. Expanding on these structural and biochemical studies to further clarify still elusive BER mechanisms, and focusing our efforts toward gaining an improved appreciation of how these enzymes form co-complexes to facilitate DNA repair is a crucial next step toward understanding how BER contributes to human maladies and how it can be manipulated to alter patient outcomes.
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Affiliation(s)
- Amy M Whitaker
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, 66160
| | - Matthew A Schaich
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, 66160
| | - Mallory R Smith
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, 66160
| | - Tony S Flynn
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, 66160
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, 66160,
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33
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Repair of oxidatively induced DNA damage by DNA glycosylases: Mechanisms of action, substrate specificities and excision kinetics. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 771:99-127. [PMID: 28342455 DOI: 10.1016/j.mrrev.2017.02.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Indexed: 02/07/2023]
Abstract
Endogenous and exogenous reactive species cause oxidatively induced DNA damage in living organisms by a variety of mechanisms. As a result, a plethora of mutagenic and/or cytotoxic products are formed in cellular DNA. This type of DNA damage is repaired by base excision repair, although nucleotide excision repair also plays a limited role. DNA glycosylases remove modified DNA bases from DNA by hydrolyzing the glycosidic bond leaving behind an apurinic/apyrimidinic (AP) site. Some of them also possess an accompanying AP-lyase activity that cleaves the sugar-phosphate chain of DNA. Since the first discovery of a DNA glycosylase, many studies have elucidated the mechanisms of action, substrate specificities and excision kinetics of these enzymes present in all living organisms. For this purpose, most studies used single- or double-stranded oligodeoxynucleotides with a single DNA lesion embedded at a defined position. High-molecular weight DNA with multiple base lesions has been used in other studies with the advantage of the simultaneous investigation of many DNA base lesions as substrates. Differences between the substrate specificities and excision kinetics of DNA glycosylases have been found when these two different substrates were used. Some DNA glycosylases possess varying substrate specificities for either purine-derived lesions or pyrimidine-derived lesions, whereas others exhibit cross-activity for both types of lesions. Laboratory animals with knockouts of the genes of DNA glycosylases have also been used to provide unequivocal evidence for the substrates, which had previously been found in in vitro studies, to be the actual substrates in vivo as well. On the basis of the knowledge gained from the past studies, efforts are being made to discover small molecule inhibitors of DNA glycosylases that may be used as potential drugs in cancer therapy.
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34
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Wickramaratne S, Banda DM, Ji S, Manlove AH, Malayappan B, Nuñez NN, Samson L, Campbell C, David SS, Tretyakova N. Base Excision Repair of N 6-Deoxyadenosine Adducts of 1,3-Butadiene. Biochemistry 2016; 55:6070-6081. [PMID: 27552084 DOI: 10.1021/acs.biochem.6b00553] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The important industrial and environmental carcinogen 1,3-butadiene (BD) forms a range of adenine adducts in DNA, including N6-(2-hydroxy-3-buten-1-yl)-2'-deoxyadenosine (N6-HB-dA), 1,N6-(2-hydroxy-3-hydroxymethylpropan-1,3-diyl)-2'-deoxyadenosine (1,N6-HMHP-dA), and N6,N6-(2,3-dihydroxybutan-1,4-diyl)-2'-deoxyadenosine (N6,N6-DHB-dA). If not removed prior to DNA replication, these lesions can contribute to A → T and A → G mutations commonly observed following exposure to BD and its metabolites. In this study, base excision repair of BD-induced 2'-deoxyadenosine (BD-dA) lesions was investigated. Synthetic DNA duplexes containing site-specific and stereospecific (S)-N6-HB-dA, (R,S)-1,N6-HMHP-dA, and (R,R)-N6,N6-DHB-dA adducts were prepared by a postoligomerization strategy. Incision assays with nuclear extracts from human fibrosarcoma (HT1080) cells have revealed that BD-dA adducts were recognized and cleaved by a BER mechanism, with the relative excision efficiency decreasing in the following order: (S)-N6-HB-dA > (R,R)-N6,N6-DHB-dA > (R,S)-1,N6-HMHP-dA. The extent of strand cleavage at the adduct site was decreased in the presence of BER inhibitor methoxyamine and by competitor duplexes containing known BER substrates. Similar strand cleavage assays conducted using several eukaryotic DNA glycosylases/lyases (AAG, Mutyh, hNEIL1, and hOGG1) have failed to observe correct incision products at the BD-dA lesion sites, suggesting that a different BER enzyme may be involved in the removal of BD-dA adducts in human cells.
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Affiliation(s)
- Susith Wickramaratne
- Masonic Cancer Center and Departments of Chemistry and Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Douglas M Banda
- Department of Chemistry, University of California , Davis, California 95616, United States
| | - Shaofei Ji
- Masonic Cancer Center and Departments of Chemistry and Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Amelia H Manlove
- Department of Chemistry, University of California , Davis, California 95616, United States
| | - Bhaskar Malayappan
- Masonic Cancer Center and Departments of Chemistry and Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Nicole N Nuñez
- Department of Chemistry, University of California , Davis, California 95616, United States
| | - Leona Samson
- Division of Biological Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Colin Campbell
- Department of Pharmacology, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Sheila S David
- Department of Chemistry, University of California , Davis, California 95616, United States
| | - Natalia Tretyakova
- Masonic Cancer Center and Departments of Chemistry and Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
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35
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Tomar JS, Peddinti RK. Optimized method for TAG protein homology modeling: In silico and experimental structural characterization. Int J Biol Macromol 2016; 88:102-12. [DOI: 10.1016/j.ijbiomac.2016.03.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 03/21/2016] [Accepted: 03/22/2016] [Indexed: 01/03/2023]
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36
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Godin SK, Zhang Z, Herken BW, Westmoreland JW, Lee AG, Mihalevic MJ, Yu Z, Sobol RW, Resnick MA, Bernstein KA. The Shu complex promotes error-free tolerance of alkylation-induced base excision repair products. Nucleic Acids Res 2016; 44:8199-215. [PMID: 27298254 PMCID: PMC5041462 DOI: 10.1093/nar/gkw535] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 06/02/2016] [Indexed: 12/24/2022] Open
Abstract
Here, we investigate the role of the budding yeast Shu complex in promoting homologous recombination (HR) upon replication fork damage. We recently found that the Shu complex stimulates Rad51 filament formation during HR through its physical interactions with Rad55-Rad57. Unlike other HR factors, Shu complex mutants are primarily sensitive to replicative stress caused by MMS and not to more direct DNA breaks. Here, we uncover a novel role for the Shu complex in the repair of specific MMS-induced DNA lesions and elucidate the interplay between HR and translesion DNA synthesis. We find that the Shu complex promotes high-fidelity bypass of MMS-induced alkylation damage, such as N3-methyladenine, as well as bypassing the abasic sites generated after Mag1 removes N3-methyladenine lesions. Furthermore, we find that the Shu complex responds to ssDNA breaks generated in cells lacking the abasic site endonucleases. At each lesion, the Shu complex promotes Rad51-dependent HR as the primary repair/tolerance mechanism over error-prone translesion DNA polymerases. Together, our work demonstrates that the Shu complex's promotion of Rad51 pre-synaptic filaments is critical for high-fidelity bypass of multiple replication-blocking lesion.
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Affiliation(s)
- Stephen K Godin
- University of Pittsburgh School of Medicine, Department of Microbiology and Molecular Genetics, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
| | - Zhuying Zhang
- University of Pittsburgh School of Medicine, Department of Microbiology and Molecular Genetics, 5117 Centre Avenue, Pittsburgh, PA 15213, USA Tsinghua University School of Medicine, Tsinghua University, Haidian District, Beijing 100084, China
| | - Benjamin W Herken
- University of Pittsburgh School of Medicine, Department of Microbiology and Molecular Genetics, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
| | - James W Westmoreland
- Chromosome Stability Group, Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Alison G Lee
- University of Pittsburgh School of Medicine, Department of Microbiology and Molecular Genetics, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
| | - Michael J Mihalevic
- University of Pittsburgh School of Medicine, Department of Microbiology and Molecular Genetics, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
| | - Zhongxun Yu
- Tsinghua University School of Medicine, Tsinghua University, Haidian District, Beijing 100084, China Department of Pharmacology & Chemical Biology, Pittsburgh, PA 15217, USA
| | - Robert W Sobol
- Department of Pharmacology & Chemical Biology, Pittsburgh, PA 15217, USA University of South Alabama Mitchell Cancer Institute, 1660 Springhill Avenue, Mobile, AL 36604, USA
| | - Michael A Resnick
- Chromosome Stability Group, Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Kara A Bernstein
- University of Pittsburgh School of Medicine, Department of Microbiology and Molecular Genetics, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
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37
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You C, Wang P, Nay SL, Wang J, Dai X, O’Connor TR, Wang Y. Roles of Aag, Alkbh2, and Alkbh3 in the Repair of Carboxymethylated and Ethylated Thymidine Lesions. ACS Chem Biol 2016; 11:1332-8. [PMID: 26930515 DOI: 10.1021/acschembio.6b00085] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Environmental and endogenous genotoxic agents can result in a variety of alkylated and carboxymethylated DNA lesions, including N3-ethylthymidine (N3-EtdT), O(2)-EtdT, and O(4)-EtdT as well as N3-carboxymethylthymidine (N3-CMdT) and O(4)-CMdT. By using nonreplicative double-stranded vectors harboring a site-specifically incorporated DNA lesion, we assessed the potential roles of alkyladenine DNA glycosylase (Aag); alkylation repair protein B homologue 2 (Alkbh2); or Alkbh3 in modulating the effects of N3-EtdT, O(2)-EtdT, O(4)-EtdT, N3-CMdT, or O(4)-CMdT on DNA transcription in mammalian cells. We found that the depletion of Aag did not significantly change the transcriptional inhibitory or mutagenic properties of all five examined lesions, suggesting a negligible role of Aag in the repair of these DNA adducts in mammalian cells. In addition, our results revealed that N3-EtdT, but not other lesions, could be repaired by Alkbh2 and Alkbh3 in mammalian cells. Furthermore, we demonstrated the direct reversal of N3-EtdT by purified human Alkbh2 protein in vitro. These findings provided important new insights into the repair of the carboxymethylated and alkylated thymidine lesions in mammalian cells.
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Affiliation(s)
- Changjun You
- Department
of Chemistry, University of California, Riverside, California, United States
| | - Pengcheng Wang
- Environmental
Toxicology Graduate Program, University of California, Riverside, California, United States
| | - Stephanie L. Nay
- Department
of Cancer Biology, Beckman Research Institute, Duarte, California, United States
| | - Jianshuang Wang
- Department
of Chemistry, University of California, Riverside, California, United States
| | - Xiaoxia Dai
- Department
of Chemistry, University of California, Riverside, California, United States
| | - Timothy R. O’Connor
- Department
of Cancer Biology, Beckman Research Institute, Duarte, California, United States
| | - Yinsheng Wang
- Department
of Chemistry, University of California, Riverside, California, United States
- Environmental
Toxicology Graduate Program, University of California, Riverside, California, United States
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38
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Jiang SY, Ramachandran S. Expansion Mechanisms and Evolutionary History on Genes Encoding DNA Glycosylases and Their Involvement in Stress and Hormone Signaling. Genome Biol Evol 2016; 8:1165-84. [PMID: 27026054 PMCID: PMC4860697 DOI: 10.1093/gbe/evw067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
DNA glycosylases catalyze the release of methylated bases. They play vital roles in the base excision repair pathway and might also function in DNA demethylation. At least three families of DNA glycosylases have been identified, which included 3′-methyladenine DNA glycosylase (MDG) I, MDG II, and HhH-GPD (Helix–hairpin–Helix and Glycine/Proline/aspartate (D)). However, little is known on their genome-wide identification, expansion, and evolutionary history as well as their expression profiling and biological functions. In this study, we have genome-widely identified and evolutionarily characterized these family members. Generally, a genome encodes only one MDG II gene in most of organisms. No MDG I or MDG II gene was detected in green algae. However, HhH-GPD genes were detectable in all available organisms. The ancestor species contain small size of MDG I and HhH-GPD families. These two families were mainly expanded through the whole-genome duplication and segmental duplication. They were evolutionarily conserved and were generally under purifying selection. However, we have detected recent positive selection among the Oryza genus, which might play roles in species divergence. Further investigation showed that expression divergence played important roles in gene survival after expansion. All of these family genes were expressed in most of developmental stages and tissues in rice plants. High ratios of family genes were downregulated by drought and fungus pathogen as well as abscisic acid (ABA) and jasmonic acid (JA) treatments, suggesting a negative regulation in response to drought stress and pathogen infection through ABA- and/or JA-dependent hormone signaling pathway.
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Affiliation(s)
- Shu-Ye Jiang
- Genome Structural Biology Group, Temasek Life Science Laboratory, The National University of Singapore, Singapore
| | - Srinivasan Ramachandran
- Genome Structural Biology Group, Temasek Life Science Laboratory, The National University of Singapore, Singapore
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39
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Lenz SAP, Wetmore SD. Evaluating the Substrate Selectivity of Alkyladenine DNA Glycosylase: The Synergistic Interplay of Active Site Flexibility and Water Reorganization. Biochemistry 2016; 55:798-808. [PMID: 26765542 DOI: 10.1021/acs.biochem.5b01179] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Human alkyladenine DNA glycosylase (AAG) functions as part of the base excision repair (BER) pathway by cleaving the N-glycosidic bond that connects nucleobases to the sugar-phosphate backbone in DNA. AAG targets a range of structurally diverse purine lesions using nonspecific DNA-protein π-π interactions. Nevertheless, the enzyme discriminates against the natural purines and is inhibited by pyrimidine lesions. This study uses molecular dynamics simulations and seven different neutral or charged substrates, inhibitors, or canonical purines to probe how the bound nucleotide affects the conformation of the AAG active site, and the role of active site residues in dictating substrate selectivity. The neutral substrates form a common DNA-protein hydrogen bond, which results in a consistent active site conformation that maximizes π-π interactions between the aromatic residues and the nucleobase required for catalysis. Nevertheless, subtle differences in DNA-enzyme contacts for different neutral substrates explain observed differential catalytic efficiencies. In contrast, the exocyclic amino groups of the natural purines clash with active site residues, which leads to catalytically incompetent DNA-enzyme complexes due to significant reorganization of active site water. Specifically, water resides between the A nucleobase and the active site aromatic amino acids required for catalysis, while a shift in the position of the general base (E125) repositions (potentially nucleophilic) water away from G. Despite sharing common amino groups, the methyl substituents in cationic purine lesions (3MeA and 7MeG) exhibit repulsion with active site residues, which repositions the damaged bases in the active site in a manner that promotes their excision. Overall, we provide a structural explanation for the diverse yet discriminatory substrate selectivity of AAG and rationalize key kinetic data available for the enzyme. Specifically, our results highlight the complex interplay of many different DNA-protein interactions used by AAG to facilitate BER, as well as the crucial role of the general base and water (nucleophile) positioning. The insights gained from our work will aid the understanding of the function of other enzymes that use flexible active sites to exhibit diverse substrate specificity.
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Affiliation(s)
- Stefan A P Lenz
- Department of Chemistry and Biochemistry, University of Lethbridge , 4401 University Drive West, Lethbridge, Alberta, Canada T1K 3M4
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge , 4401 University Drive West, Lethbridge, Alberta, Canada T1K 3M4
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40
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Bauer NC, Corbett AH, Doetsch PW. The current state of eukaryotic DNA base damage and repair. Nucleic Acids Res 2015; 43:10083-101. [PMID: 26519467 PMCID: PMC4666366 DOI: 10.1093/nar/gkv1136] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/16/2015] [Indexed: 12/15/2022] Open
Abstract
DNA damage is a natural hazard of life. The most common DNA lesions are base, sugar, and single-strand break damage resulting from oxidation, alkylation, deamination, and spontaneous hydrolysis. If left unrepaired, such lesions can become fixed in the genome as permanent mutations. Thus, evolution has led to the creation of several highly conserved, partially redundant pathways to repair or mitigate the effects of DNA base damage. The biochemical mechanisms of these pathways have been well characterized and the impact of this work was recently highlighted by the selection of Tomas Lindahl, Aziz Sancar and Paul Modrich as the recipients of the 2015 Nobel Prize in Chemistry for their seminal work in defining DNA repair pathways. However, how these repair pathways are regulated and interconnected is still being elucidated. This review focuses on the classical base excision repair and strand incision pathways in eukaryotes, considering both Saccharomyces cerevisiae and humans, and extends to some important questions and challenges facing the field of DNA base damage repair.
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Affiliation(s)
- Nicholas C Bauer
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA Graduate Program in Biochemistry, Cell, and Developmental Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Anita H Corbett
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Paul W Doetsch
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA
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Kuraoka I. Diversity of Endonuclease V: From DNA Repair to RNA Editing. Biomolecules 2015; 5:2194-206. [PMID: 26404388 PMCID: PMC4693234 DOI: 10.3390/biom5042194] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 09/09/2015] [Accepted: 09/11/2015] [Indexed: 11/16/2022] Open
Abstract
Deamination of adenine occurs in DNA, RNA, and their precursors via a hydrolytic reaction and a nitrosative reaction. The generated deaminated products are potentially mutagenic because of their structural similarity to natural bases, which in turn leads to erroneous nucleotide pairing and subsequent disruption of cellular metabolism. Incorporation of deaminated precursors into the nucleic acid strand occurs during nucleotide synthesis by DNA and RNA polymerases or base modification by DNA- and/or RNA-editing enzymes during cellular functions. In such cases, removal of deaminated products from DNA and RNA by a nuclease might be required depending on the cellular function. One such enzyme, endonuclease V, recognizes deoxyinosine and cleaves 3' end of the damaged base in double-stranded DNA through an alternative excision repair mechanism in Escherichia coli, whereas in Homo sapiens, it recognizes and cleaves inosine in single-stranded RNA. However, to explore the role of endonuclease V in vivo, a detailed analysis of cell biology is required. Based on recent reports and developments on endonuclease V, we discuss the potential functions of endonuclease V in DNA repair and RNA metabolism.
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Affiliation(s)
- Isao Kuraoka
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
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Whetstone RD, Gold B. T-cells enhance stem cell mutagenesis in the mouse colon. Mutat Res 2015; 774:1-5. [PMID: 25770826 DOI: 10.1016/j.mrfmmm.2015.02.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 02/23/2015] [Accepted: 02/24/2015] [Indexed: 06/04/2023]
Abstract
A role of inflammation in the etiology of cancer is attributed to the production of reactive oxygen/nitrogen species that can damage DNA. To test this hypothesis, we determined the mutation frequency (MF) in colonic stem cells in C57Bl/6 mice exposed to azoxymethane (AOM), dextran sulfate sodium (DSS) and a combination of AOM and DSS (AOM+DSS). AOM+DSS efficiently and rapidly produces colon tumors in B6 mice. AOM produces promutagenic O(6)-methylguanine lesions in DNA but does not induce colon tumors in C57Bl/6 mice as a single agent. DSS produces inflammation in the colon but does not produce tumors except upon multiple cycles of treatment in some DNA repair deficient mouse models. In addition, using TCRβ null mice we tested whether α/β T cells have any effect on the colonic stem cell MF in mice treated with AOM, DSS and AOM+DSS. The TCRβ(-/-) mice are devoid of the critical receptor required for normal cytolytic and regulatory α/β T-cell functions. The MF in the untreated and DSS treated WT and TCRβ(-/-) mice was the same (<10(-5)) indicating that DSS and subsequent inflammation does not generate stem cell mutations in mice that are WT for DNA repair. AOM yielded mutant crypts in WT and TCRβ(-/-) mice with MF's of ∼4×10(-4) and 2×10(-4), respectively, which represents a statistically significant decrease in the MF in the immune compromised mice. The combined treatment of AOM+DSS afforded fully mutated crypts in both strains with a statistically significant lower MF in the TCRβ(-/-) mice. In addition, the MF in both strains of mice after the combination of AOM+DSS is lower than observed with AOM alone indicating that DSS inflammation destroyed pre-existing AOM mutated crypts. Using the MF in WT mice, the efficiency for the conversion of promutagenic O(6)-methylguanine lesions into a stem cell mutations was calculated to be ∼0.4%.
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Affiliation(s)
- Ryan D Whetstone
- Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, United States
| | - Barry Gold
- Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, United States.
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Leitner-Dagan Y, Sevilya Z, Pinchev M, Kremer R, Elinger D, Rennert HS, Schechtman E, Freedman L, Rennert G, Livneh Z, Paz-Elizur T. Enzymatic MPG DNA repair assays for two different oxidative DNA lesions reveal associations with increased lung cancer risk. Carcinogenesis 2014; 35:2763-70. [PMID: 25355292 DOI: 10.1093/carcin/bgu214] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
DNA repair is a major mechanism for minimizing mutations and reducing cancer risk. Here, we present the development of reproducible and specific enzymatic assays for methylpurine DNA glycosylase (MPG) repairing the oxidative lesions 1,N6-ethenoadenine (εA) and hypoxanthine (Hx) in peripheral blood mononuclear cells protein extracts. Association of these DNA repair activities with lung cancer was determined using conditional logistic regression with specimens from a population-based case-control study with 96 lung cancer cases and 96 matched control subjects. The mean MPG-εA in case patients was 15.8 units/μg protein (95% CI 15.3-16.3), significantly higher than in control subjects-15.1 (14.6-15.5), *P = 0.011. The adjusted odds ratio for lung cancer associated with a one SD increase in MPG-εA activity (2.48 units) was significantly bigger than 1 (OR = 1.6, 95% CI = 1.1-2.4; *P = 0.013). When activity of OGG1, a different DNA repair enzyme for oxidative damage, was included in the model, the estimated odds ratio/SD for a combined MPG-εA-OGG1 score was 2.6 (95% CI 1.6-4.2) *P = 0.0001, higher than the odds ratio for each single assay. The MPG enzyme activity assays described provide robust functional risk biomarkers, with increased MPG-εA activity being associated with increased lung cancer risk, similar to the behavior of MPG-Hx. This underscores the notion that imbalances in DNA repair, including high DNA repair, usually perceived as beneficial, can cause cancer risk. Such DNA repair risk biomarkers may be useful for risk assessment of lung cancer and perhaps other cancer types, and for early detection techniques such as low-dose CT.
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Affiliation(s)
- Yael Leitner-Dagan
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel, Department of General Thoracic Surgery, Rambam Health Care Campus, Haifa, Israel, Department of Industrial Engineering and Management, Ben Gurion University of the Negev, Beer Sheva 84105, Israel and Biostatistics Unit, Gertner Institute for Epidemiology and Public Health Policy Sheba Medical Center Tel Hashomer 52621, Israel
| | - Ziv Sevilya
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel, Department of General Thoracic Surgery, Rambam Health Care Campus, Haifa, Israel, Department of Industrial Engineering and Management, Ben Gurion University of the Negev, Beer Sheva 84105, Israel and Biostatistics Unit, Gertner Institute for Epidemiology and Public Health Policy Sheba Medical Center Tel Hashomer 52621, Israel
| | - Mila Pinchev
- Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel
| | - Ran Kremer
- Department of General Thoracic Surgery, Rambam Health Care Campus, Haifa, Israel
| | - Dalia Elinger
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel, Department of General Thoracic Surgery, Rambam Health Care Campus, Haifa, Israel, Department of Industrial Engineering and Management, Ben Gurion University of the Negev, Beer Sheva 84105, Israel and Biostatistics Unit, Gertner Institute for Epidemiology and Public Health Policy Sheba Medical Center Tel Hashomer 52621, Israel
| | - Hedy S Rennert
- Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel
| | - Edna Schechtman
- Department of Industrial Engineering and Management, Ben Gurion University of the Negev, Beer Sheva 84105, Israel and
| | - Laurence Freedman
- Biostatistics Unit, Gertner Institute for Epidemiology and Public Health Policy Sheba Medical Center Tel Hashomer 52621, Israel
| | - Gad Rennert
- Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel
| | - Zvi Livneh
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel, Department of General Thoracic Surgery, Rambam Health Care Campus, Haifa, Israel, Department of Industrial Engineering and Management, Ben Gurion University of the Negev, Beer Sheva 84105, Israel and Biostatistics Unit, Gertner Institute for Epidemiology and Public Health Policy Sheba Medical Center Tel Hashomer 52621, Israel
| | - Tamar Paz-Elizur
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Community Medicine and Epidemiology, Carmel Medical Center, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and Clalit Health Services National Cancer Control Center, Haifa, Israel, Department of General Thoracic Surgery, Rambam Health Care Campus, Haifa, Israel, Department of Industrial Engineering and Management, Ben Gurion University of the Negev, Beer Sheva 84105, Israel and Biostatistics Unit, Gertner Institute for Epidemiology and Public Health Policy Sheba Medical Center Tel Hashomer 52621, Israel
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Aag-initiated base excision repair promotes ischemia reperfusion injury in liver, brain, and kidney. Proc Natl Acad Sci U S A 2014; 111:E4878-86. [PMID: 25349415 DOI: 10.1073/pnas.1413582111] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Inflammation is accompanied by the release of highly reactive oxygen and nitrogen species (RONS) that damage DNA, among other cellular molecules. Base excision repair (BER) is initiated by DNA glycosylases and is crucial in repairing RONS-induced DNA damage; the alkyladenine DNA glycosylase (Aag/Mpg) excises several DNA base lesions induced by the inflammation-associated RONS release that accompanies ischemia reperfusion (I/R). Using mouse I/R models we demonstrate that Aag(-/-) mice are significantly protected against, rather than sensitized to, I/R injury, and that such protection is observed across three different organs. Following I/R in liver, kidney, and brain, Aag(-/-) mice display decreased hepatocyte death, cerebral infarction, and renal injury relative to wild-type. We infer that in wild-type mice, Aag excises damaged DNA bases to generate potentially toxic abasic sites that in turn generate highly toxic DNA strand breaks that trigger poly(ADP-ribose) polymerase (Parp) hyperactivation, cellular bioenergetics failure, and necrosis; indeed, steady-state levels of abasic sites and nuclear PAR polymers were significantly more elevated in wild-type vs. Aag(-/-) liver after I/R. This increase in PAR polymers was accompanied by depletion of intracellular NAD and ATP levels plus the translocation and extracellular release of the high-mobility group box 1 (Hmgb1) nuclear protein, activating the sterile inflammatory response. We thus demonstrate the detrimental effects of Aag-initiated BER during I/R and sterile inflammation, and present a novel target for controlling I/R-induced injury.
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Meira LB, Calvo JA, Shah D, Klapacz J, Moroski-Erkul CA, Bronson RT, Samson LD. Repair of endogenous DNA base lesions modulate lifespan in mice. DNA Repair (Amst) 2014; 21:78-86. [PMID: 24994062 PMCID: PMC4125484 DOI: 10.1016/j.dnarep.2014.05.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 04/30/2014] [Accepted: 05/20/2014] [Indexed: 12/21/2022]
Abstract
The accumulation of DNA damage is thought to contribute to the physiological decay associated with the aging process. Here, we report the results of a large-scale study examining longevity in various mouse models defective in the repair of DNA alkylation damage, or defective in the DNA damage response. We find that the repair of spontaneous DNA damage by alkyladenine DNA glycosylase (Aag/Mpg)-initiated base excision repair and O(6)-methylguanine DNA methyltransferase (Mgmt)-mediated direct reversal contributes to maximum life span in the laboratory mouse. We also uncovered important genetic interactions between Aag, which excises a wide variety of damaged DNA bases, and the DNA damage sensor and signaling protein, Atm. We show that Atm plays a role in mediating survival in the face of both spontaneous and induced DNA damage, and that Aag deficiency not only promotes overall survival, but also alters the tumor spectrum in Atm(-/-) mice. Further, the reversal of spontaneous alkylation damage by Mgmt interacts with the DNA mismatch repair pathway to modulate survival and tumor spectrum. Since these aging studies were performed without treatment with DNA damaging agents, our results indicate that the DNA damage that is generated endogenously accumulates with age, and that DNA alkylation repair proteins play a role in influencing longevity.
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Affiliation(s)
- Lisiane B Meira
- Biological Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Jennifer A Calvo
- Biological Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Dharini Shah
- Biological Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Joanna Klapacz
- Biological Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Catherine A Moroski-Erkul
- Biological Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Roderick T Bronson
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Rodent Histopathology Core, Harvard Medical School, 126 Goldenson Building, Boston, MA 02115, United States
| | - Leona D Samson
- Biological Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Biology Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Rodent Histopathology Core, Harvard Medical School, 126 Goldenson Building, Boston, MA 02115, United States.
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Kisby GE, Moore H, Spencer PS. Animal models of brain maldevelopment induced by cycad plant genotoxins. BIRTH DEFECTS RESEARCH. PART C, EMBRYO TODAY : REVIEWS 2013; 99:247-55. [PMID: 24339036 PMCID: PMC4183057 DOI: 10.1002/bdrc.21052] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/24/2013] [Indexed: 01/12/2023]
Abstract
Cycads are long-lived tropical and subtropical plants that contain azoxyglycosides (e.g., cycasin, macrozamin) and neurotoxic amino acids (notably β-N-methylamino-l-alanine l-BMAA), toxins that have been implicated in the etiology of a disappearing neurodegenerative disease, amyotrophic lateral sclerosis and parkinsonism-dementia complex that has been present in high incidence among three genetically distinct populations in the western Pacific. The neuropathology of amyotrophic lateral sclerosis/parkinsonism-dementia complex includes features suggestive of brain maldevelopment, an experimentally proven property of cycasin attributable to the genotoxic action of its aglycone methylazoxymethanol (MAM). This property of MAM has been exploited by neurobiologists as a tool to study perturbations of brain development. Depending on the neurodevelopmental stage, MAM can induce features in laboratory animals that model certain characteristics of epilepsy, schizophrenia, or ataxia. Studies in DNA repair-deficient mice show that MAM perturbs brain development through a DNA damage-mediated mechanism. The brain DNA lesions produced by systemic MAM appear to modulate the expression of genes that regulate neurodevelopment and contribute to neurodegeneration. Epigenetic changes (histone lysine methylation) have also been detected in the underdeveloped brain after MAM administration. The DNA damage and epigenetic changes produced by MAM and, perhaps by chemically related substances (e.g., nitrosamines, nitrosoureas, hydrazines), might be an important mechanism by which early-life exposure to genotoxicants can induce long-term brain dysfunction.
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Affiliation(s)
- Glen E. Kisby
- Department of Basic Medical Sciences, Western University of Health Sciences, College of Osteopathic Medicine of the Pacific Northwest, Lebanon, Oregon, 97355
| | - Holly Moore
- Department of Psychiatry, Columbia University and Department of Integrative Neuroscience, New York State Psychiatric Institute, New York, NY
| | - Peter S. Spencer
- Department of Neurology, School of Medicine, Center for Research on Occupational and Environmental Toxciology; and Global Health Center, Oregon Health and Science University, Portland, Oregon, 97201
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The effect of Msh2 knockdown on toxicity induced by tert-butyl-hydroperoxide, potassium bromate, and hydrogen peroxide in base excision repair proficient and deficient cells. BIOMED RESEARCH INTERNATIONAL 2013; 2013:152909. [PMID: 23984319 PMCID: PMC3747367 DOI: 10.1155/2013/152909] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 07/03/2013] [Accepted: 07/10/2013] [Indexed: 01/02/2023]
Abstract
The DNA mismatch repair (MMR) and base excision repair (BER) systems are important determinants of cellular toxicity following exposure to agents that cause oxidative DNA damage. To examine the interactions between these different repair systems, we examined whether toxicity, induced by t-BOOH and KBrO3, differs in BER proficient (Mpg+/+, Nth1+/+) and deficient (Mpg−/−, Nth1−/−) mouse embryonic fibroblasts (MEFs) following Msh2 knockdown of between 79 and 88% using an shRNA expression vector. Msh2 knockdown in Nth1+/+ cells had no effect on t-BOOH and KBrO3 induced toxicity as assessed by an MTT assay; knockdown in Nth1−/− cells resulted in increased resistance to t-BOOH and KBrO3, a result consistent with Nth1 removing oxidised pyrimidines. Msh2 knockdown in Mpg+/+ cells had no effect on t-BOOH toxicity but increased resistance to KBrO3; in Mpg−/− cells, Msh2 knockdown increased cellular sensitivity to KBrO3 but increased resistance to t-BOOH, suggesting a role for Mpg in removing DNA damage induced by these agents. MSH2 dependent and independent pathways then determine cellular toxicity induced by oxidising agents. A complex interaction between MMR and BER repair systems, that is, exposure dependent, also exists to determine cellular toxicity.
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Calvo JA, Moroski-Erkul CA, Lake A, Eichinger LW, Shah D, Jhun I, Limsirichai P, Bronson RT, Christiani DC, Meira LB, Samson LD. Aag DNA glycosylase promotes alkylation-induced tissue damage mediated by Parp1. PLoS Genet 2013; 9:e1003413. [PMID: 23593019 PMCID: PMC3617098 DOI: 10.1371/journal.pgen.1003413] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 02/11/2013] [Indexed: 12/21/2022] Open
Abstract
Alkylating agents comprise a major class of front-line cancer chemotherapeutic compounds, and while these agents effectively kill tumor cells, they also damage healthy tissues. Although base excision repair (BER) is essential in repairing DNA alkylation damage, under certain conditions, initiation of BER can be detrimental. Here we illustrate that the alkyladenine DNA glycosylase (AAG) mediates alkylation-induced tissue damage and whole-animal lethality following exposure to alkylating agents. Aag-dependent tissue damage, as observed in cerebellar granule cells, splenocytes, thymocytes, bone marrow cells, pancreatic β-cells, and retinal photoreceptor cells, was detected in wild-type mice, exacerbated in Aag transgenic mice, and completely suppressed in Aag−/− mice. Additional genetic experiments dissected the effects of modulating both BER and Parp1 on alkylation sensitivity in mice and determined that Aag acts upstream of Parp1 in alkylation-induced tissue damage; in fact, cytotoxicity in WT and Aag transgenic mice was abrogated in the absence of Parp1. These results provide in vivo evidence that Aag-initiated BER may play a critical role in determining the side-effects of alkylating agent chemotherapies and that Parp1 plays a crucial role in Aag-mediated tissue damage. Alkylating agents are genotoxic chemicals that induce both toxic and mutagenic DNA damage through addition of an alkyl group to DNA. Alkylating agents are routinely and successfully used as chemotherapeutic therapies for cancer patients, with one major disadvantage being the significant toxicity induced in non-tumor tissues. Accordingly, identifying factors that modify susceptibility to alkylation-induced toxicity will provide valuable information in designing cancer therapeutic regimens. This study used mouse genetic experiments to investigate whether proteins important in the base excision repair pathway modulate susceptibility to alkylating agents. In addition to whole-animal toxicity at high doses, treatment of mice with alkylating agents resulted in severe damage to numerous tissues including the cerebellum, retina, bone marrow, spleen, thymus, and the pancreas. We illustrate that the DNA glycosylase Aag can actually confer, rather than prevent, alkylation sensitivity at both the whole-animal and tissue level; i.e., Aag transgenic animals are more susceptible than wild type, whereas Aag-deficient animals are less susceptible than wild type to alkylation-induced toxicity. Further genetic experiments show that the Aag-mediated alkylation sensitivity is dependent on Parp1. Given that we observe a wide range of human AAG expression among healthy individuals, this and other base excision repair proteins may be important factors modulating alkylation susceptibility.
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Affiliation(s)
- Jennifer A. Calvo
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Catherine A. Moroski-Erkul
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Annabelle Lake
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Lindsey W. Eichinger
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Dharini Shah
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Iny Jhun
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Prajit Limsirichai
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Roderick T. Bronson
- Department of Pathology, Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - David C. Christiani
- Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Lisiane B. Meira
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Leona D. Samson
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
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van Loon B, Samson LD. Alkyladenine DNA glycosylase (AAG) localizes to mitochondria and interacts with mitochondrial single-stranded binding protein (mtSSB). DNA Repair (Amst) 2013; 12:177-87. [PMID: 23290262 DOI: 10.1016/j.dnarep.2012.11.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 11/21/2012] [Accepted: 11/26/2012] [Indexed: 12/12/2022]
Abstract
Due to a harsh environment mitochondrial genomes accumulate high levels of DNA damage, in particular oxidation, hydrolytic deamination, and alkylation adducts. While repair of alkylated bases in nuclear DNA has been explored in detail, much less is known about the repair of DNA alkylation damage in mitochondria. Alkyladenine DNA glycosylase (AAG) recognizes and removes numerous alkylated bases, but to date AAG has only been detected in the nucleus, even though mammalian mitochondria are known to repair DNA lesions that are specific substrates of AAG. Here we use immunofluorescence to show that AAG localizes to mitochondria, and we find that native AAG is present in purified human mitochondrial extracts, as well as that exposure to alkylating agent promotes AAG accumulation in the mitochondria. We identify mitochondrial single-stranded binding protein (mtSSB) as a novel interacting partner of AAG; interaction between mtSSB and AAG is direct and increases upon methyl methanesulfonate (MMS) treatment. The consequence of this interaction is specific inhibition of AAG glycosylase activity in the context of a single-stranded DNA (ssDNA), but not a double-stranded DNA (dsDNA) substrate. By inhibiting AAG-initiated processing of damaged bases, mtSSB potentially prevents formation of DNA breaks in ssDNA, ensuring that base removal primarily occurs in dsDNA. In summary, our findings suggest the existence of AAG-initiated BER in mitochondria and further support a role for mtSSB in DNA repair.
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Affiliation(s)
- Barbara van Loon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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50
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Bosshard M, Markkanen E, van Loon B. Base excision repair in physiology and pathology of the central nervous system. Int J Mol Sci 2012. [PMID: 23203191 PMCID: PMC3546685 DOI: 10.3390/ijms131216172] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Relatively low levels of antioxidant enzymes and high oxygen metabolism result in formation of numerous oxidized DNA lesions in the tissues of the central nervous system. Accumulation of damage in the DNA, due to continuous genotoxic stress, has been linked to both aging and the development of various neurodegenerative disorders. Different DNA repair pathways have evolved to successfully act on damaged DNA and prevent genomic instability. The predominant and essential DNA repair pathway for the removal of small DNA base lesions is base excision repair (BER). In this review we will discuss the current knowledge on the involvement of BER proteins in the maintenance of genetic stability in different brain regions and how changes in the levels of these proteins contribute to aging and the onset of neurodegenerative disorders.
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Affiliation(s)
- Matthias Bosshard
- Institute for Veterinary Biochemistry and Molecular Biology, University of Zürich-Irchel, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
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