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Judice SA, Sussman HE, Walker DM, O'Neill JP, Albertini RJ, Walker VE. Clonality, trafficking, and molecular alterations among Hprt mutant T lymphocytes isolated from control mice versus mice treated with N-ethyl-N-nitrosourea. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2023; 64:432-457. [PMID: 37957787 PMCID: PMC10842105 DOI: 10.1002/em.22579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/03/2023] [Accepted: 11/10/2023] [Indexed: 11/15/2023]
Abstract
Mutations in T lymphocytes (T-cells) are informative quantitative markers for environmental mutagen exposures, but risk extrapolations from rodent models to humans also require an understanding of how T-cell development and proliferation kinetics impact mutagenic outcomes. Rodent studies have shown that patterns in chemical-induced mutations in the hypoxanthine-guanine phosphoribosyltransferase (Hprt) gene of T-cells differ between lymphoid organs. The current work was performed to obtain knowledge of the relationships between maturation events during T-cell development and changes in chemical-induced mutant frequencies over time in differing immune compartments of a mouse model. A novel reverse transcriptase-polymerase chain reaction based method was developed to determine the specific T-cell receptor beta (Tcrb) gene mRNA expressed in mouse T-cell isolates, enabling sequence analysis of the PCR product that then identifies the specific hypervariable CDR3 junctional region of the expressed Tcrb gene for individual isolates. Characterization of spontaneous Hprt mutant isolates from the thymus, spleen, and lymph nodes of control mice for their Tcrb gene expression found evidence of in vivo clonal amplifications of Hprt mutants and their trafficking between tissues in the same animal. Concurrent analyses of Hprt mutations and Tcrb gene rearrangements in different lymphoid tissues of control versus N-ethyl-N-nitrosourea-exposed mice permitted elucidation of the localization and timing of mutational events in T-cells, establishing that mutagenesis occurs primarily in the pre-rearrangement replicative period in pre-thymic/thymic populations. These findings demonstrate that chemical-induced mutagenic burden is determined by the combination of mutagenesis and T-cell clonal expansion, processes with roles in immune function and in the pathogenesis of autoimmune disease and cancer.
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Affiliation(s)
- Stephen A Judice
- Genetic Toxicology Laboratory, University of Vermont, Burlington, Vermont, USA
- EnviroLogix, Portland, Maine, USA
| | - Hillary E Sussman
- School of Public Health, University at Albany - SUNY, Albany, New York, USA
- New York State Department of Health, Wadsworth Center, Albany, New York, USA
- Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, USA
| | - Dale M Walker
- Experimental Pathology Laboratories, Sterling, Virginia, USA
- The Burlington HC Research group, Inc., Jericho, Vermont, USA
| | - J Patrick O'Neill
- Genetic Toxicology Laboratory, University of Vermont, Burlington, Vermont, USA
| | - Richard J Albertini
- Genetic Toxicology Laboratory, University of Vermont, Burlington, Vermont, USA
- Department of Pathology and Laboratory Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
| | - Vernon E Walker
- New York State Department of Health, Wadsworth Center, Albany, New York, USA
- Department of Pathology and Laboratory Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
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2
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Dodge AE, LeBlanc DPM, Zhou G, Williams A, Meier MJ, Van P, Lo FY, Valentine Iii CC, Salk JJ, Yauk CL, Marchetti F. Duplex sequencing provides detailed characterization of mutation frequencies and spectra in the bone marrow of MutaMouse males exposed to procarbazine hydrochloride. Arch Toxicol 2023; 97:2245-2259. [PMID: 37341741 PMCID: PMC10322784 DOI: 10.1007/s00204-023-03527-y] [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: 02/23/2023] [Accepted: 05/17/2023] [Indexed: 06/22/2023]
Abstract
Mutagenicity testing is an essential component of health safety assessment. Duplex Sequencing (DS), an emerging high-accuracy DNA sequencing technology, may provide substantial advantages over conventional mutagenicity assays. DS could be used to eliminate reliance on standalone reporter assays and provide mechanistic information alongside mutation frequency (MF) data. However, the performance of DS must be thoroughly assessed before it can be routinely implemented for standard testing. We used DS to study spontaneous and procarbazine (PRC)-induced mutations in the bone marrow (BM) of MutaMouse males across a panel of 20 diverse genomic targets. Mice were exposed to 0, 6.25, 12.5, or 25 mg/kg-bw/day for 28 days by oral gavage and BM sampled 42 days post-exposure. Results were compared with those obtained using the conventional lacZ viral plaque assay on the same samples. DS detected significant increases in mutation frequencies and changes to mutation spectra at all PRC doses. Low intra-group variability within DS samples allowed for detection of increases at lower doses than the lacZ assay. While the lacZ assay initially yielded a higher fold-change in mutant frequency than DS, inclusion of clonal mutations in DS mutation frequencies reduced this discrepancy. Power analyses suggested that three animals per dose group and 500 million duplex base pairs per sample is sufficient to detect a 1.5-fold increase in mutations with > 80% power. Overall, we demonstrate several advantages of DS over classical mutagenicity assays and provide data to support efforts to identify optimal study designs for the application of DS as a regulatory test.
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Affiliation(s)
- Annette E Dodge
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Danielle P M LeBlanc
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Gu Zhou
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Andrew Williams
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Matthew J Meier
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Phu Van
- TwinStrand Biosciences Inc., Seattle, Washington, USA
| | - Fang Yin Lo
- TwinStrand Biosciences Inc., Seattle, Washington, USA
| | | | - Jesse J Salk
- TwinStrand Biosciences Inc., Seattle, Washington, USA
| | - Carole L Yauk
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
- Department of Biology, Carleton University, Ottawa, Ontario, Canada.
| | - Francesco Marchetti
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada.
- Department of Biology, Carleton University, Ottawa, Ontario, Canada.
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3
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Revollo JR, McKinzie PB, Robison TW, Dobrovolsky VN. Mutational signatures in T-lymphocytes of rats treated with N-propyl-N-nitrosourea and procarbazine. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2021; 62:350-363. [PMID: 34117657 DOI: 10.1002/em.22448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/12/2021] [Accepted: 06/09/2021] [Indexed: 06/12/2023]
Abstract
We have used whole genome sequencing (WGS) to determine mutational signatures induced in the T-cells of rats treated in vivo with N-propyl-N-nitrosourea (PNU) or procarbazine (PCZ). The signatures from the treated rats were different from the signature of background mutations. The main component of the spontaneous T-cell mutational signature was C➔T transition with all other single base substitutions evenly distributed. The PNU-induced mutational signature showed relatively equal contributions from C➔T and T➔C transitions, and T➔A transversions. The PCZ-induced signature was characterized by T➔C transitions, T➔A and, to a smaller extent, T➔G transversions. C➔G transversions were infrequent in either the PNU or PCZ signatures. WGS not only allowed mutational signature detection, but also measured quantitative responses to mutagen treatment: 10-40× increases in the number of mutations per clone were detected in T-cell clones from treated rats. The overall strand specificity of induced mutations for annotated rat genes was comparable to the strand specificity of mutations determined previously for the endogenous X-linked Pig-a gene. Our results provide valuable reference data for future applications of WGS in safety research and risk assessment.
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Affiliation(s)
- Javier R Revollo
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
| | - Page B McKinzie
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
| | - Timothy W Robison
- Division of Pulmonary, Allergy and Critical Care Products, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Vasily N Dobrovolsky
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
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4
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Dad A, Revollo JR, Pearce MG, McKinzie PB, Heflich RH, Dobrovolsky VN. Pig-a gene mutations in bone marrow granulocytes of procarbazine-treated F344 rats. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2021; 62:265-272. [PMID: 33666279 DOI: 10.1002/em.22430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 06/12/2023]
Abstract
It was previously demonstrated that procarbazine (PCZ) is positive in the rat erythrocyte Pig-a gene mutation assay. However, since mammalian erythrocytes lack genomic DNA, it was necessary to analyze nucleated bone-marrow erythroid precursor cells to confirm that PCZ induces mutations in the Pig-a gene (Revollo et al., Environ Mol Mutagen, 2020). In this study, the association between Pig-a mutation and loss of GPI anchors was further strengthened and the genesis of Pig-a mutation in PCZ-dosed rats was evaluated by analyzing bone-marrow granulocytes. Erythrocytes and granulocytes both originate from myeloid progenitor cells, but granulocytes contain DNA throughout their developmental stages. F344 rats were treated with three doses of 150 mg/kg PCZ; 2 weeks later, CD48-deficient mutant phenotype bone-marrow granulocytes (BMGs [CD11b+ ]) were isolated by flow-cytometric sorting. Sequencing data showed that the CD48-deficient mutant phenotype BMGs contained mutations in the Pig-a gene while wild-type BMGs did not. PCZ-induced mutations included missense, nonsense and splice site variants; the majority of mutations were A > T, A > C, and A > G, with the mutated A on the nontranscribed DNA strand. The PCZ-induced mutational analysis in BMGs supports the association between the phenotype measured in the Pig-a assay and mutation in the Pig-a gene. Also, PCZ mutation spectra were similar in bone-marrow erythroids and BMGs, but none of the mutations detected in BMGs were the same as the erythroid precursor cell mutations from the same rats. Thus, mutations induced in the Pig-a assay appear to be induced after commitment of myeloid progenitor cells to either the granulocyte or erythroid pathway.
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Affiliation(s)
- Azra Dad
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
| | - Javier R Revollo
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
| | - Mason G Pearce
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
| | - Page B McKinzie
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
| | - Robert H Heflich
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
| | - Vasily N Dobrovolsky
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
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Revollo JR, Dad A, Pearce MG, Mittelstaedt RA, Casildo A, Lapidus RG, Robison TW, Dobrovolsky VN. CD59-deficient bone marrow erythroid cells from rats treated with procarbazine and propyl-nitrosourea have mutations in the Pig-a gene. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2020; 61:797-806. [PMID: 32729949 DOI: 10.1002/em.22402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/09/2020] [Accepted: 07/24/2020] [Indexed: 06/11/2023]
Abstract
Procarbazine (PCZ) and N-propyl-N-nitrosourea (PNU) are rodent mutagens and carcinogens. Both induce GPI-anchored marker-deficient mutant-phenotype red blood cells (RBCs) in the flow cytometry-based rat RBC Pig-a assay. In the present study, we traced the origin of the RBC mutant phenotype by analyzing Pig-a mutations in the precursors of RBCs, bone marrow erythroid cells (BMEs). Rats were exposed to a total of 450 mg/kg PCZ hydrochloride or 300 mg/kg PNU, and bone marrow was collected 2, 7, and 10 weeks later. Using a flow cell sorter, we isolated CD59-deficient mutant-phenotype BMEs from PCZ- and PNU-treated rats and examined their endogenous X-linked Pig-a gene by next generation sequencing. Pig-a mutations consistent with the properties of PCZ and PNU were found in sorted mutant-phenotype BMEs. PCZ induced mainly A > T transversions with the mutated A on the nontranscribed strand of the Pig-a gene, while PNU induced mainly T > A transversions with the mutated T on the nontranscribed strand. The treatment-induced mutations were distributed across the protein coding sequence of the Pig-a gene. The causal relationship between BMEs and RBCs and the agent-specific mutational spectra in CD59-deicient BMEs indicate that the rat RBC Pig-a assay, scoring CD59-deficient mutant-phenotype RBCs in peripheral blood, detects Pig-a gene mutation.
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Affiliation(s)
- Javier R Revollo
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
| | - Azra Dad
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
| | - Mason G Pearce
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
| | - Roberta A Mittelstaedt
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
| | - Andrea Casildo
- Greenbaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Rena G Lapidus
- Greenbaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Timothy W Robison
- Division of Pulmonary, Allergy and Critical Care Products, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Vasily N Dobrovolsky
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
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6
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Beal MA, Meier MJ, LeBlanc DP, Maurice C, O'Brien JM, Yauk CL, Marchetti F. Chemically induced mutations in a MutaMouse reporter gene inform mechanisms underlying human cancer mutational signatures. Commun Biol 2020; 3:438. [PMID: 32796912 PMCID: PMC7429849 DOI: 10.1038/s42003-020-01174-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 07/24/2020] [Indexed: 02/07/2023] Open
Abstract
Transgenic rodent (TGR) models use bacterial reporter genes to quantify in vivo mutagenesis. Pairing TGR assays with next-generation sequencing (NGS) enables comprehensive mutation pattern analysis to inform mutational mechanisms. We used this approach to identify 2751 independent lacZ mutations in the bone marrow of MutaMouse animals exposed to four chemical mutagens: benzo[a]pyrene, N-ethyl-N-nitrosourea, procarbazine, and triethylenemelamine. We also collected published data for 706 lacZ mutations from eight additional environmental mutagens. We report that lacZ gene sequencing generates chemical-specific mutation signatures observed in human cancers with established environmental causes. For example, the mutation signature of benzo[a]pyrene, a carcinogen present in tobacco smoke, matched the signature associated with tobacco-induced lung cancers. Our results suggest that the analysis of chemically induced mutations in the lacZ gene shortly after exposure provides an effective approach to characterize human-relevant mechanisms of carcinogenesis and propose novel environmental causes of mutation signatures observed in human cancers. Marc A. Beal, Matt J. Meier et al. use a transgenic rodent model with NGS to inform mutational signature analyses. They analyze lacZ mutations from the bone marrow of MutaMouse animals exposed to chemical mutagens. They report that lacZ sequencing generates chemical-specific mutation signatures observed in human cancers with established environmental causes.
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Affiliation(s)
- Marc A Beal
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, K1A 0K9, Canada.,Existing Substances Risk Assessment Bureau, Health Canada, Ottawa, ON, Canada
| | - Matthew J Meier
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, K1A 0K9, Canada
| | - Danielle P LeBlanc
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, K1A 0K9, Canada
| | - Clotilde Maurice
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, K1A 0K9, Canada.,Existing Substances Risk Assessment Bureau, Health Canada, Ottawa, ON, Canada
| | - Jason M O'Brien
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, ON, K1A 0H3, Canada
| | - Carole L Yauk
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, K1A 0K9, Canada
| | - Francesco Marchetti
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, K1A 0K9, Canada.
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7
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Abstract
In addition to chromosomal damage, assessment of gene mutation is an important part of genotoxicity testing employed during preclinical safety testing. The Pig-a gene mutation assay is based on the loss of function of the Pig-a gene, which results in a lack of cell surface expression of specific proteins that are targeted to the surface by GPI anchors. This cell surface phenotype is readily assessed by flow cytometric analysis of red blood cells. This chapter describes a procedure for the collection, processing, and analysis of peripheral blood samples using materials supplied in MutaFlow® kits and a common benchtop flow cytometer.
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8
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Revollo JR, Dad A, Pearce MG, Mittelstaedt RA, Robison TW, Dobrovolsky VN. Pig-a mutations in bone marrow erythroblasts of rats treated with 7,12-dimethyl-benz[a]anthracene. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 848:503106. [DOI: 10.1016/j.mrgentox.2019.503106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 10/04/2019] [Accepted: 10/11/2019] [Indexed: 11/30/2022]
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9
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Kirkland D, Uno Y, Luijten M, Beevers C, van Benthem J, Burlinson B, Dertinger S, Douglas GR, Hamada S, Horibata K, Lovell DP, Manjanatha M, Martus HJ, Mei N, Morita T, Ohyama W, Williams A. In vivo genotoxicity testing strategies: Report from the 7th International workshop on genotoxicity testing (IWGT). MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 847:403035. [PMID: 31699340 DOI: 10.1016/j.mrgentox.2019.03.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/13/2019] [Accepted: 03/23/2019] [Indexed: 12/14/2022]
Abstract
The working group reached complete or majority agreement on many issues. Results from TGR and in vivo comet assays for 91 chemicals showed they have similar ability to detect in vivo genotoxicity per se with bacterial mutagens and Ames-positive carcinogens. TGR and comet assay results were not significantly different when compared with IARC Group 1, 2 A, and unclassified carcinogens. There were significantly more comet assay positive responses for Group 2B chemicals, and for IARC classified and unclassified carcinogens combined, which may be expected since mutation is a sub-set of genotoxicity. A liver comet assay combined with the bone marrow/blood micronucleus (MNviv) test would detect in vivo genotoxins that do not exhibit tissue-specific or site-of-contact effects, and is appropriate for routine in vivo genotoxicity testing. Generally for orally administered substances, a comet assay at only one site-of-contact GI tract tissue (stomach or duodenum/jejunum) is required. In MNviv tests, evidence of target tissue exposure can be obtained in a number of different ways, as recommended by ICH S2(R1) and EFSA (Hardy et al., 2017). Except for special cases the i.p. route is inappropriate for in vivo testing; for risk evaluations more weight should be given to data from a physiologically relevant administration route. The liver MN test is sufficiently validated for the development of an OECD guideline. However, the impact of dosing animals >6 weeks of age needs to be evaluated. The GI tract MN test shows promise but needs more validation for an OECD guideline. The Pig-a assay detects systemically available mutagens and is a valuable follow-up to in vitro positive results. A new freeze-thaw protocol provides more flexibility. Mutant reticulocyte and erythrocyte frequencies should both be determined. Preliminary data are available for the Pig-a assay in male rat germ cells which require validation including germ cell DNA mutation origin.
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Affiliation(s)
- David Kirkland
- Kirkland Consulting, PO Box 79, Tadcaster, LS24 0AS, United Kingdom.
| | - Yoshifumi Uno
- Mitsubishi Tanabe Pharma Corporation, 2-2-50, Kawagishi, Toda, Saitama, 335-8505, Japan
| | - Mirjam Luijten
- National Institute for Public Health and the Environment (RIVM), Centre for Health Protection, Bilthoven, the Netherlands
| | - Carol Beevers
- Exponent International Ltd., The Lenz, Hornbeam Park, Harrogate, HG2 8RE, United Kingdom
| | - Jan van Benthem
- National Institute for Public Health and the Environment (RIVM), Centre for Health Protection, Bilthoven, the Netherlands
| | - Brian Burlinson
- Envigo, Huntingdon, Cambridgeshire, PE28 4HS, United Kingdom
| | | | - George R Douglas
- Environmental Health Science Research Bureau, Health Canada, Ottawa, K1A 0K9, Canada
| | - Shuichi Hamada
- LSI Medience Corporation, 14-1 Sunayama, Kamisu-shi, Ibaraki, 314-0255, Japan
| | - Katsuyoshi Horibata
- National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki, Kanagawa, 210-9501, Japan
| | - David P Lovell
- St George's Medical School, University of London, London, SW17 0RE, United Kingdom
| | | | | | - Nan Mei
- US FDA, National Center for Toxicological Research, Jefferson, AR, USA
| | - Takeshi Morita
- National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki, Kanagawa, 210-9501, Japan
| | - Wakako Ohyama
- Yakult Honsha Co., Ltd., 5-11, Izumi, Kunitachi-shi, Tokyo, 186-8650, Japan
| | - Andrew Williams
- Environmental Health Science Research Bureau, Health Canada, Ottawa, K1A 0K9, Canada
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10
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Chen G, Wen H, Mao Z, Song J, Jiang H, Wang W, Yang Y, Miao Y, Wang C, Huang Z, Wang X. Assessment of the Pig-a, micronucleus, and comet assay endpoints in rats treated by acute or repeated dosing protocols with procarbazine hydrochloride and ethyl carbamate. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:56-71. [PMID: 30240497 DOI: 10.1002/em.22227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 06/12/2018] [Accepted: 06/24/2018] [Indexed: 06/08/2023]
Abstract
The utility and sensitivity of the newly developed flow cytometric Pig-a gene mutation assay have become a great concern recently. In this study, we have examined the feasibility of integrating the Pig-a assay as well as micronucleus and Comet endpoints into acute and subchronic general toxicology studies. Male Sprague-Dawley rats were treated for 3 or 28 consecutive days by oral gavage with procarbazine hydrochloride (PCZ) or ethyl carbamate (EC) up to the maximum tolerated dose. The induction of CD59-negative reticulocytes and erythrocytes, micronucleated reticulocytes in peripheral blood, micronucleated polychromatic erythrocytes in bone marrow, and Comet responses in peripheral blood, liver, kidney, and lung were evaluated at one, two, or more timepoints. Both PCZ and EC produced positive responses at most analyzed timepoints in all tissue types, both with the 3-day and 28-day treatment regimens. Furthermore, comparison of the magnitude of the genotoxicity responses indicated that the micronucleus and Comet endpoints generally produced greater responses with the higher dose, short-term treatments in the 3-day study, while the Pig-a assay responded better to the cumulative effects of the lower dose, but repeated subchronic dosing in the 28-day study. Collectively, these results indicate that integration of several in vivo genotoxicity endpoints into a single routine toxicology study is feasible and that the Pig-a assay may be particularly suitable for integration into subchronic dose studies based on its ability to accumulate the mutations that result from repeated treatments. This characteristic may be especially important for assaying lower doses of relatively weak genotoxicants. Environ. Mol. Mutagen. 60:56-71, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Gaofeng Chen
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
- Center of Safety Evaluation on New Drug, School of Pharmaceutical Science, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Hairuo Wen
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Zhihui Mao
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
- Center of Safety Evaluation on New Drug, School of Pharmaceutical Science, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Jie Song
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Hua Jiang
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Weifan Wang
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Ying Yang
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Yufa Miao
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Chao Wang
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
| | - Zhiying Huang
- Center of Safety Evaluation on New Drug, School of Pharmaceutical Science, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Xue Wang
- Key Laboratory of Beijing for Safety Evaluation of Drugs, National Center for Safety Evaluation of Drugs, National Institutes for Food and Drug Control, Beijing, People's Republic of China
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11
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Dad A, Revollo JR, Petibone DM, Pearce MG, Heflich RH, Dobrovolsky VN. Analysis of mutation in the rat Pig-a assay: II. Studies with bone marrow granulocytes. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2018; 59:733-741. [PMID: 30091248 DOI: 10.1002/em.22210] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/08/2018] [Accepted: 05/10/2018] [Indexed: 06/08/2023]
Abstract
The in vivo erythrocyte Pig-a gene mutation assay measures the phenotypic loss of GPI-anchored surface markers. Molecular analysis of the marker-deficient erythrocytes cannot provide direct proof that the mutant phenotype is due to mutation in the Pig-a gene because mammalian erythrocytes lack genomic DNA. Granulocytes are nucleated cells that originate from myeloid progenitor cells in bone marrow as is the case for erythrocytes, and thus analysis of Pig-a mutation in bone marrow granulocytes can provide information about the source of mutations detected in the erythrocyte Pig-a assay. We developed a flow cytometric Pig-a assay for bone marrow granulocytes and evaluated granulocyte Pig-a mutant frequencies in bone marrow from male rats treated acutely with N-ethyl-N-nitrosourea (ENU). Bone marrow cells from these rats were stained with anti-CD11b for identifying granulocytes and anti-CD48 for detecting the Pig-a mutant phenotype. The average Pig-a mutant frequency in granulocyte precursors of control rats was 8.42 × 10-6 , whereas in ENU-treated rats it was 567.13 × 10-6 . CD11b-positive/CD48-deficient mutant cells were enriched using magnetic separation and sorted into small pools for sequencing. While there were no Pig-a mutations found in sorted CD48-positive wild-type cells, Pig-a mutations were detected in mutant granulocyte precursors. The most frequent mutation observed was T→A transversion, followed by T→C transition and T→G transversion, with the mutated T on the nontranscribed DNA strand. While the spectrum of mutations in bone marrow granulocytes was similar to that of erythroid cells, different Pig-a mutations were found in mutant-phenotype granulocytes and erythroids from the same bone marrow samples, suggesting that most Pig-a mutations were induced in bone marrow cells after commitment to either the granulocyte or erythroid developmental pathway. Environ. Mol. Mutagen. 59:733-741, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Azra Dad
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
| | - Javier R Revollo
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
| | - Dayton M Petibone
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
| | - Mason G Pearce
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
| | - Robert H Heflich
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
| | - Vasily N Dobrovolsky
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
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Revollo JR, Pearce MG, Dad A, Petibone DM, Robison TW, Roberts D, Dobrovolsky VN. Analysis of mutation in the rat Pig-a assay: I) studies with bone marrow erythroid cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2018; 59:722-732. [PMID: 30091272 DOI: 10.1002/em.22211] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/08/2018] [Accepted: 05/10/2018] [Indexed: 06/08/2023]
Abstract
We have established a flow cytometry-based Pig-a assay for rat bone marrow erythroid cells (BMEs). The BME Pig-a assay uses a DNA-specific stain and two antibodies: one against the transmembrane transferrin receptor (CD71 marker) and the other against the GPI-anchored complement inhibitory protein (CD59 marker). In F344 male rats treated acutely with a total of 120 mg/kg of N-ethyl-N-nitrosourea (ENU) the frequency of CD59-deficient phenotypically mutant BMEs increased approximately 24-fold compared to the rats concurrently treated with the vehicle. Such an increase of mutant BMEs coincides with increases of CD59-deficient reticulocytes measured in rats treated with similar doses of ENU. Sequence analysis of the endogenous X-linked Pig-a gene of CD59-deficient BMEs revealed that they are Pig-a mutants. The spectrum of ENU-induced Pig-a mutations in these BMEs was consistent with the in vivo mutagenic signature of ENU: 73% of mutations occurred at A:T basepairs, with the mutated T on the nontranscribed strand of the gene. T→A transversion was the most frequent mutation followed by T→C transition; no deletion or insertion mutations were present in the spectrum. Since BMEs are precursors of peripheral red blood cells, our findings suggest that CD59-deficient erythrocytes measured in the flow cytometric erythrocyte Pig-a assay develop from BMEs containing mutations in the Pig-a gene. Thus, the erythrocyte Pig-a assay detects mutation in the Pig-a gene. Environ. Mol. Mutagen. 59:722-732, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Javier R Revollo
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
| | - Mason G Pearce
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
| | - Azra Dad
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
| | - Dayton M Petibone
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
| | - Timothy W Robison
- Division of Pulmonary, Allergy, and Rheumatology Products, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland
| | - Daniel Roberts
- Charles River Laboratories, Skokie, Illinois; Joint Graduate Program of Toxicology, Rutgers University, Piscataway, New Jersey
| | - Vasily N Dobrovolsky
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
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Elhajouji A, Vaskova D, Downing R, Dertinger SD, Martus H. Induction ofin vivo Pig-agene mutation but not micronuclei by 5-(2-chloroethyl)-2ʹ-deoxyuridine, an antiviral pyrimidine nucleoside analogue. Mutagenesis 2018; 33:343-350. [DOI: 10.1093/mutage/gey029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 09/10/2018] [Indexed: 11/14/2022] Open
Affiliation(s)
- Azeddine Elhajouji
- Preclinical Safety, Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Dagmara Vaskova
- Preclinical Safety, Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Rebecca Downing
- Preclinical Safety, Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
| | | | - Hansjeorg Martus
- Preclinical Safety, Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
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Revollo JR, Dad A, McDaniel LP, Pearce MG, Dobrovolsky VN. Genome-wide mutation detection by interclonal genetic variation. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2018; 829-830:61-69. [PMID: 29704995 DOI: 10.1016/j.mrgentox.2018.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/10/2018] [Accepted: 03/10/2018] [Indexed: 12/20/2022]
Abstract
Genetic toxicology assays estimate mutation frequencies by phenotypically screening for the activation or inactivation of endogenous or exogenous reporter genes. These reporters can only detect mutations in narrow areas of the genome and their use is often restricted to certain in vitro and in vivo models. Here, we show that Interclonal Genetic Variation (ICGV) can directly identify mutations genome-wide by comparing sequencing data of single-cell clones derived from the same source or organism. Upon ethyl methanesulfonate (EMS) exposure, ICGV detected greater levels of mutation in a dose- and time-dependent manner in E. coli. In addition, ICGV was also able to identify a ∼20-fold increase in somatic mutations in T-cell clones derived from an N-ethyl-N-nitrosourea (ENU)-treated rat vs. a vehicle-treated rat. These results demonstrate that the genetic differences of single-cell clones can be used for genome-wide mutation detection.
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Affiliation(s)
- Javier R Revollo
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR, USA.
| | - Azra Dad
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR, USA
| | - Lea P McDaniel
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR, USA
| | - Mason G Pearce
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR, USA
| | - Vasily N Dobrovolsky
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR, USA
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