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Lawrence R, Munn K, Naser H, Thomas L, Haboubi H, Williams L, Doak S, Jenkins G. The PIG-A gene mutation assay in human biomonitoring and disease. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2023; 64:480-493. [PMID: 37926486 DOI: 10.1002/em.22577] [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: 08/25/2023] [Revised: 10/11/2023] [Accepted: 11/01/2023] [Indexed: 11/07/2023]
Abstract
The blood cell phosphatidylinositol glycan class A (PIG-A) gene mutation assay has been extensively researched in rodents for in vivo mutagenicity testing and is now being investigated in humans. The PIG-A gene is involved in glycosyl phosphatidylinositol (GPI)-anchor biosynthesis. A single mutation in this X-linked gene can lead to loss of membrane-bound GPI anchors, which can be enumerated via corresponding GPI-anchored proteins (e.g., CD55) using flow cytometry. The studies published to date by different research groups demonstrate a remarkable consistency in PIG-A mutant frequencies. Moreover, with the low background level of mutant erythrocytes in healthy subjects (2.9-5.56 × 10-6 mutants), induction of mutation post genotoxic exposure can be detected. Cigarette smoking, radiotherapy, and occupational exposures, including lead, have been shown to increase mutant levels. Future applications of this test include identifying new harmful agents and establishing new exposure limits. This mutational monitoring approach may also identify individuals at higher risk of cancer development. In addition, identifying protective agents that could mitigate these effects may reduce baseline somatic mutation levels and such behaviors can be encouraged. Further technological progress is required including establishing underlying mechanisms of GPI anchor loss, protocol standardization, and the development of cryopreservation methods to improve GPI-anchor stability over time. If successful, this assay has the potential be widely employed, for example, in rural and low-income countries. Here, we review the current literature on PIG-A mutation in humans and discuss the potential role of this assay in human biomonitoring and disease detection.
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Affiliation(s)
- Rachel Lawrence
- Centre for Biomarkers and Biotherapeutics, Barts Cancer Institute, Queen Mary University of London, London, UK
| | - Kathryn Munn
- Swansea University Medical School, Swansea University, Swansea, UK
| | - Hamsa Naser
- Swansea University Medical School, Swansea University, Swansea, UK
| | - Laura Thomas
- Swansea University Medical School, Swansea University, Swansea, UK
| | - Hasan Haboubi
- Department of Gastroenterology, University Hospital Llandough, Cardiff and Vale University Health Board, Cardiff, UK
| | - Lisa Williams
- Department of Gastroenterology, Singleton Hospital, Swansea Bay University Health Board, Swansea, UK
| | - Shareen Doak
- Swansea University Medical School, Swansea University, Swansea, UK
| | - Gareth Jenkins
- Swansea University Medical School, Swansea University, Swansea, UK
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Seo JE, Davis K, Malhi P, He X, Bryant M, Talpos J, Burks S, Mei N, Guo X. Genotoxicity evaluation using primary hepatocytes isolated from rhesus macaque (Macaca mulatta). Toxicology 2021; 462:152936. [PMID: 34509578 DOI: 10.1016/j.tox.2021.152936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/04/2021] [Accepted: 09/07/2021] [Indexed: 10/20/2022]
Abstract
Non-human primates (NHPs) have played a vital role in fundamental, pre-clinical, and translational studies because of their high physiological and genetic similarity to humans. Here, we report a method to isolate primary hepatocytes from the livers of rhesus macaques (Macaca mulatta) after in situ whole liver perfusion. Isolated primary macaque hepatocytes (PMHs) were treated with various compounds known to have different pathways of genotoxicity/carcinogenicity and the resulting DNA damage was evaluated using the high-throughput CometChip assay. The comet data were quantified using benchmark dose (BMD) modeling and the BMD50 values for treatments of PMHs were compared with those generated from primary human hepatocytes (PHHs) in our previous study (Seo et al. Arch Toxicol 2020, 2207-2224). The results showed that despite varying CYP450 enzyme activities, PMHs had the same sensitivity and specificity as PHHs in detecting four indirect-acting (i.e., requiring metabolic activation) and seven direct-acting genotoxicants/carcinogens, as well as five non-carcinogens that are negative or equivocal for genotoxicity in vivo. The BMD50 estimates and their confidence intervals revealed species differences for DNA damage potency, especially for direct-acting compounds. The present study provides a practical method for maximizing the use of animal tissues by isolating primary hepatocytes from NHPs. Our data support the use of PMHs as a reliable surrogate of PHHs for evaluating the genotoxic hazards of chemical substances for humans.
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Affiliation(s)
- Ji-Eun Seo
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - Kelly Davis
- Toxicologic Pathology Associates, Jefferson, AR 72079, USA
| | - Pritpal Malhi
- Toxicologic Pathology Associates, Jefferson, AR 72079, USA
| | - Xiaobo He
- Office of Scientific Coordination, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - Matthew Bryant
- Office of Scientific Coordination, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - John Talpos
- Division of Neurotoxicology, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - Susan Burks
- Division of Neurotoxicology, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - Nan Mei
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - Xiaoqing Guo
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, USA.
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3
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Zhou CH, Yu CR, Huang PC, Li RW, Wang JT, Zhao TT, Zhao ZH, Ma J, Chang Y. In Vitro PIG-A Gene Mutation Assay in Human B-Lymphoblastoid TK6 Cells. PHARMACEUTICAL FRONTS 2021. [DOI: 10.1055/s-0041-1735146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
AbstractThe X-linked PIG-A gene is involved in the biosynthesis of glycosylphosphatidylinositol (GPI) anchors. PIG-A mutant cells fail to synthesize GPI and to express GPI-anchored protein markers (e.g., CD59 and CD55). In recent years, in vitro PIG-A assay has been established based on the high conservation of PIG-A/Pig-a loci among different species and the large data from the in vivo system. The purpose of this study was to extend the approach for PIG-A mutation assessment to in vitro human B-lymphoblastoid TK6 cells by detecting the loss of GPI-linked CD55 and CD59 proteins. TK6 cells were treated with three mutagens 7,12-dimethylbenz[a]anthracene (DMBA), N-ethyl-N-nitrosourea (ENU), etoposide (ETO), and two nonmutagens: cadmium chloride (CdCl2) and sodium chloride (NaCl). The mutation rate of PIG-A gene within TK6 cells was determined on the 11th day with flow cytometry analysis for the negative frequencies of CD55 and CD59. The antibodies used in this production were APC mouse-anti-human CD19 antibody, PE mouse anti-human CD55 antibody, PE mouse anti-human CD59 antibody, and nucleic acid dye 7-AAD. An immunolabeling method was used to reduce the high spontaneous level of preexisting PIG-A mutant cells. Our data suggested that DMBA-, ENU-, and ETO-induced mutation frequency of PIG-A gene was increased by twofold compared with the negative control, and the effects were dose-dependent. However, CdCl2 and NaCl did not significantly increase the mutation frequency of PIG-A gene, with a high cytotoxicity at a dose of 10 mmol/L. Our study suggested that the novel in vitro PIG-A gene mutation assay within TK6 cells may represent a complement of the present in vivo Pig-a assay, and may provide guidance for their potential use in genotoxicity even in cells with a significant deficiency of GPI anchor.
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Affiliation(s)
- Chang-Hui Zhou
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Chun-Rong Yu
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Peng-Cheng Huang
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Ruo-Wan Li
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Jing-Ting Wang
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Tian-Tian Zhao
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Ze-Hao Zhao
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Jing Ma
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Yan Chang
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
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Lawrence R, Haboubi H, Williams L, Doak S, Jenkins G. Dietary and lifestyle factors effect erythrocyte PIG-A mutant frequency in humans. Mutagenesis 2020; 35:geaa025. [PMID: 33043963 DOI: 10.1093/mutage/geaa025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 09/07/2020] [Indexed: 01/22/2023] Open
Abstract
It is well understood that poor diet and lifestyle choices can increase the risk of cancer. It is also well documented that cancer is a disease of DNA mutations, with mutations in key genes driving carcinogenesis. Measuring these mutations in a minimally invasive way may be informative as to which exposures are harmful and thus allow us to introduce primary preventative measures, in a bid to reduce cancer incidences. Here, we have measured mutations in the phosphatidylinositol glycan class A (PIG-A) gene in erythrocytes from healthy volunteers (n = 156) and from non-cancer patients attending the local endoscopy department (n = 144). The X-linked PIG-A gene encodes an enzyme involved in glycosylphosphatidylinositol (GPI) anchor synthesis. A silencing mutation in which leads to the absence of GPI anchors on the extracellular surface which can be rapidly assessed using flow cytometry. The background level of PIG-A mutant erythrocytes was 2.95 (95% CI: 2.59-3.67) mutant cells (10-6). Older age increased mutant cell frequency (P < 0.001). There was no difference in mutant cell levels between males and females (P = 0.463) or smokers and non-smokers (P = 0.186). In the endoscopy group, aspirin users had lower mutant frequencies (P = 0.001). Further information on diet and exercise was available for the endoscopy patient group alone, where those with a higher health promotion index score had lower mutant frequencies (P = 0.011). Higher dietary intake of vegetables reduced mutant cell levels (P = 0.022). Participants who exercised for at least 1 h a week appeared to have reduced mutant frequencies than those who did not exercise, although this was not statistically significant (P = 0.099). This low background level of mutant erythrocytes in a population makes this assay an attractive tool to monitor exposures such as those associated with lifestyles and diet, as demonstrated here.
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Affiliation(s)
| | | | - Lisa Williams
- Department of Endoscopy, Swansea Bay University Health Board, Swansea, UK
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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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6
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Developing a blood-based gene mutation assay as a novel biomarker for oesophageal adenocarcinoma. Sci Rep 2019; 9:5168. [PMID: 30914682 PMCID: PMC6435702 DOI: 10.1038/s41598-019-41490-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 03/06/2019] [Indexed: 12/20/2022] Open
Abstract
The Phosphatidylinositol glycan class A (PIG-A) gene mutation assay phenotypically measures erythrocyte mutations, assessed here for their correlation to neoplastic progression in the gastro-oesophageal reflux disease (GORD)-Barrett’s metaplasia (BM)-oesophageal adenocarcinoma (OAC) model. Endoscopy patients underwent venipuncture and erythrocytes fluorescently stained for glycosyl phosphatidylinositol (GPI)–anchored proteins; CD55 and CD59. Using flow cytometry, GPI–anchor negative erythrocytes (mutants) were scored and compared amongst groups. The study enlisted 200 patients and 137 healthy volunteers. OAC patients had a three–fold increase in erythrocyte mutant frequency (EMF) compared to GORD patients (p < 0.001) and healthy volunteers (p < 0.001). In OAC patients, higher EMF was associated with worsening tumour staging (p = 0.014), nodal involvement (p = 0.019) and metastatic disease (p = 0.008). Chemotherapy patients demonstrated EMF’s over 19–times higher than GORD patients. Patients were further classified into groups containing those with non-neoplastic disease and those with high-grade dysplasia/cancer with 72.1% of cases correctly classified by high EMF. Within the non-neoplastic group, aspirin users had lower EMF (p = 0.001) and there was a positive correlation between body mass index (p = 0.03) and age (p < 0.001) and EMF. Smokers had EMF’s over double that of non-smokers (p = 0.011). Results suggest this test could help detect OAC and may be a useful predictor of disease progression.
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Bemis JC, Heflich RH. In vitro mammalian cell mutation assays based on the Pig-a gene: A report of the 7th International Workshop on Genotoxicity Testing (IWGT) Workgroup. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 847:403028. [PMID: 31699348 DOI: 10.1016/j.mrgentox.2019.03.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 01/29/2019] [Accepted: 03/04/2019] [Indexed: 02/06/2023]
Abstract
Pig-a gene mutation assays enumerate cells with the glycosylphosphatidylinositol (GPI) anchor-deficient phenotype as a reporter of mutation in the endogenous Pig-a gene. Methods for measuring mutation in this gene are quite well established for in vivo systems. This approach to mutagenicity assessment has now been extended to in vitro mammalian cell-based systems. An expert workgroup from the 7th International Workshop on Genotoxicity Testing tasked with assessing the status of in vitro mammalian cell mutation assays has investigated the merits and limitations of in vitro Pig-a gene mutation assays. A review of the current status of these developing methodologies and the formation of consensus statements on the utility and application of these assays were performed to provide guidance for their potential use in genotoxicity hazard identification and risk assessment.
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Affiliation(s)
- J C Bemis
- Litron Laboratories, Rochester, NY, USA.
| | - R H Heflich
- US Food and Drug Administration, National Center for Toxicological Research, Jefferson, AR, USA
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Mittelstaedt RA, Dobrovolsky VN, Revollo JR, Pearce MG, Wang Y, Dad A, McKinzie PB, Rosenfeldt H, Yucesoy B, Yeager R, Hu SC, Tang Y, Min S, Kang HK, Yang DJ, Basavarajappa M, Heflich RH. Evaluation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) mutagenicity using in vitro and in vivo Pig-a assays. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 837:65-72. [PMID: 30595212 DOI: 10.1016/j.mrgentox.2018.10.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/26/2018] [Accepted: 10/26/2018] [Indexed: 02/06/2023]
Abstract
4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a genotoxic carcinogen found in tobacco and tobacco smoke. Several in vitro and in vivo assays have been used for evaluating the genotoxicity of tobacco smoke and tobacco smoke constituents like NNK, yet it is not clear which in vitro assays are most appropriate for extrapolating the in vitro responses of these test agents to animal models and humans. The Pig-a gene mutation assay can be performed in vitro, in laboratory animals, and in humans, a potential benefit in estimating in vivo responses from in vitro data. In the current study we used Pig-a as a reporter of gene mutation both in vitro, in L5178Y/Tk+/- cells, and in vivo, in Sprague-Dawley rats. NNK significantly increased Pig-a mutant frequency in L5178Y/Tk+/- cells, but only at concentrations of 100 μg/ml and greater, and only in the presence of S9 activation. Pig-a mutations in L5178Y/Tk+/- cells were detected in 80% of the NNK-induced mutants, with the predominate mutation being G→A transition; vehicle control mutants contained deletions. In the in vivo study, rats were exposed to NNK daily for 90 days by inhalation, a common route of exposure to NNK for humans. Although elevated mutant frequencies were detected, these responses were not clearly associated with NNK exposure, so that overall, the in vivo Pig-a assays were negative. Thus, while NNK induces mutations in the in vitro Pig-a assay, the in vivo Pig-a assay has limited ability to detect NNK mutagenicity under conditions relevant to NNK exposure in smokers.
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Affiliation(s)
- Roberta A Mittelstaedt
- U.S. Food and Drug Administration, Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, USA
| | - Vasily N Dobrovolsky
- U.S. Food and Drug Administration, Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, USA
| | - Javier R Revollo
- U.S. Food and Drug Administration, Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, USA
| | - Mason G Pearce
- U.S. Food and Drug Administration, Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, USA
| | - Yiying Wang
- U.S. Food and Drug Administration, Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, USA
| | - Azra Dad
- U.S. Food and Drug Administration, Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, USA
| | - Page B McKinzie
- U.S. Food and Drug Administration, Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, USA
| | - Hans Rosenfeldt
- U.S. Food and Drug Administration, Division of Nonclinical Science, Office of Science, Center for Tobacco Products, USA
| | - Berran Yucesoy
- U.S. Food and Drug Administration, Division of Nonclinical Science, Office of Science, Center for Tobacco Products, USA
| | - Raymond Yeager
- U.S. Food and Drug Administration, Division of Nonclinical Science, Office of Science, Center for Tobacco Products, USA
| | - Shu-Chieh Hu
- U.S. Food and Drug Administration, Inhalcore, Office of Scientific Coordination, National Center for Toxicological Research, USA
| | - Yunan Tang
- U.S. Food and Drug Administration, Inhalcore, Office of Scientific Coordination, National Center for Toxicological Research, USA
| | - Seonggi Min
- U.S. Food and Drug Administration, Inhalcore, Office of Scientific Coordination, National Center for Toxicological Research, USA
| | - Hyun-Ki Kang
- U.S. Food and Drug Administration, Inhalcore, Office of Scientific Coordination, National Center for Toxicological Research, USA
| | - Dong-Jin Yang
- U.S. Food and Drug Administration, Inhalcore, Office of Scientific Coordination, National Center for Toxicological Research, USA
| | - Mallikarjuna Basavarajappa
- U.S. Food and Drug Administration, Inhalcore, Office of Scientific Coordination, National Center for Toxicological Research, USA
| | - Robert H Heflich
- U.S. Food and Drug Administration, Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, USA.
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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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10
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Kopp B, Vignard J, Mirey G, Fessard V, Zalko D, Le Hgarat L, Audebert M. Genotoxicity and mutagenicity assessment of food contaminant mixtures present in the French diet. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2018; 59:742-754. [PMID: 30230031 DOI: 10.1002/em.22214] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/22/2018] [Accepted: 05/29/2018] [Indexed: 06/08/2023]
Abstract
Through diet, people are exposed simultaneously to a variety of contaminants (e.g. heavy metals, mycotoxins, pesticides) that could have combined adverse effects on human health. A previous study identified six main mixtures of food contaminants to which French adult consumers are exposed. These complex mixtures are comprised of 11 to 19 chemicals that have numerous toxic properties. In the present study, we investigated the genotoxic effects of these food contaminants, as single molecules and in mixtures that reflect their occurrence in the French diet, using the γH2AX assay in two human cell lines (HepG2, LS-174 T). Results of detailed analysis of the 49 individual contaminants (including 21 tested in this study) demonstrated a positive genotoxic response to 14 contaminants in HepG2 and 12 in LS-174 T cells. Next, our results indicated that two mixtures out of six triggered significant γH2AX induction after 24 hr of treatment, at concentrations for which individual compounds did not induce any DNA damage, suggesting more than additive interactions between chemicals. γH2AX positive mixtures were then tested for mutagenicity with the innovative in vitro PIG-A assay in HepG2 cells coupled with the soft agar colony formation assay. The two γH2AX positive mixtures led to a significant increase in the frequency of PIG-A GPI-deficient cells and in the number of colonies formed in soft agar. In conclusion, our study demonstrates that two mixtures of contaminants present in the French diet induce genotoxicity and mutagenicity, and that the combined effects of single molecules present in these mixtures are likely not additive, highlighting potential problems for hazard assessment of mixtures. Environ. Mol. Mutagen. 59:742-754, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- B Kopp
- Toxalim, Université de Toulouse, INRA, INP-ENVT, INP-EI-Purpan, Université de Toulouse 3 Paul Sabatier, Toulouse, France
- ANSES (French Agency for Food, Environmental and Occupational Health and Safety), Toxicology of Contaminants Unit, Fougères, France
| | - J Vignard
- Toxalim, Université de Toulouse, INRA, INP-ENVT, INP-EI-Purpan, Université de Toulouse 3 Paul Sabatier, Toulouse, France
| | - G Mirey
- Toxalim, Université de Toulouse, INRA, INP-ENVT, INP-EI-Purpan, Université de Toulouse 3 Paul Sabatier, Toulouse, France
| | - V Fessard
- ANSES (French Agency for Food, Environmental and Occupational Health and Safety), Toxicology of Contaminants Unit, Fougères, France
| | - D Zalko
- Toxalim, Université de Toulouse, INRA, INP-ENVT, INP-EI-Purpan, Université de Toulouse 3 Paul Sabatier, Toulouse, France
| | - L Le Hgarat
- ANSES (French Agency for Food, Environmental and Occupational Health and Safety), Toxicology of Contaminants Unit, Fougères, France
| | - M Audebert
- Toxalim, Université de Toulouse, INRA, INP-ENVT, INP-EI-Purpan, Université de Toulouse 3 Paul Sabatier, Toulouse, France
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11
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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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12
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Spectrum of benzo[ a ]pyrene-induced mutations in the Pig-a gene of L5178Y Tk +/− cells identified with next generation sequencing. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2017; 824:1-8. [DOI: 10.1016/j.mrgentox.2017.09.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/01/2017] [Accepted: 09/01/2017] [Indexed: 11/19/2022]
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