1
|
Rowan-Carroll A, Beal MA, Williams A, Marchetti F, Yauk CL. Dose-response mutation and spectrum analyses reveal similar responses at two microsatellite loci in benzo(a)pyrene-exposed mouse spermatogonia. Mutagenesis 2018; 32:463-470. [PMID: 28575466 DOI: 10.1093/mutage/gex008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/23/2017] [Indexed: 11/14/2022] Open
Abstract
Identifying chemical exposures that can cause germline mutations is important as these mutations can be inherited, impacting both individual and population health. However, germline mutations are extremely rare and difficult to detect. Chemically induced germline mutations can be detected through analysis of highly unstable tandem repeat DNA. We recently developed a single-molecule PCR (SM-PCR) approach to quantify mutations at a mouse microsatellite locus (Mm2.2.1) in sperm for such purposes. In this study, we refine this approach through the combined analysis of mouse microsatellites Mm2.2.1 and Mm19.2.3. Mice were exposed to 0, 25, 50 or 100 mg/kg/day benzo(a)pyrene (BaP) by oral gavage for 28 days and sperm sampled 42 days after the end of exposure to measure effects on dividing spermatogonia. DNA was diluted to a single genome per PCR well for amplification of microsatellites in singleplex and multiplex reactions, and alleles were sized to identify mutations using capillary electrophoresis. Analysis of ~300-500 molecules per animal at both microsatellite loci, when tested individually, showed a ~2-fold increase in mutations relative to the controls at both the 50 and 100 mg/kg/day BaP doses. Multiplex SM-PCR revealed similar increases in mutation frequencies in both microsatellites. Comparison with results from a previous lacZ mutation assay conducted on the same mice revealed that although microsatellite mutations are a sensitive endpoint for detecting changes in mutation frequencies at lower doses, they appear to be saturable and thus have a reduced dynamic range. These results confirm that BaP is a male germ cell mutagen that broadly impacts tandem repeat DNA. Likewise, addition of a second hypervariable microsatellite increases the sensitivity of this assay.
Collapse
Affiliation(s)
- Andrea Rowan-Carroll
- Mechanistic Studies Division, Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario K1A 0K9, Canada
| | - Marc A Beal
- Mechanistic Studies Division, Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario K1A 0K9, Canada
| | - Andrew Williams
- Biostatistics and Epidemiology Division, Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Francesco Marchetti
- Mechanistic Studies Division, Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario K1A 0K9, Canada
| | - Carole L Yauk
- Mechanistic Studies Division, Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario K1A 0K9, Canada
| |
Collapse
|
2
|
Aoki Y. Evaluation of in vivo mutagenesis for assessing the health risk of air pollutants. Genes Environ 2017; 39:16. [PMID: 28373898 PMCID: PMC5376282 DOI: 10.1186/s41021-016-0064-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 12/06/2016] [Indexed: 11/16/2022] Open
Abstract
Various kind of chemical substances, including man-made chemical products and unintended products, are emitted to ambient air. Some of these substances have been shown to be mutagenic and therefore to act as a carcinogen in humans. National pollutant inventories (e.g., Pollutant Release and Transfer Registration in Japan) have estimated release amounts of man-made chemical products, but a major concern is the release of suspended particulate matter containing potent mutagens, for example, polycyclic aromatic hydrocarbons and related compounds generated by the combustion of fossil fuel, which are not estimated by PRTR system. In situ exposure studies have revealed that DNA adducts in the lung, and possibly mutations in germline cells are induced in rodents by inhalation of ambient air, indicating that evaluating in vivo mutations is important for assessing environmental health risks. Transgenic rodent systems (Muta, Big Blue, and gpt delta) are good tools for analyzing in vivo mutations induced by a mixture of chemical substances present in the environment. Following inhalation of diesel exhaust (used as a model mixture), mutation frequency was increased in the lung of gpt delta mice and base substitutions were induced at specific guanine residues (mutation hotspots) on the target transgenes. Mutation hotspots induced by diesel exhaust were different from those induced by benzo[a]pyrene, a typical mutagen in ambient air, but nearly identical to those induced by 1,6-dinitropyrene contained in diesel exhaust. Comparison between mutation hotspots in the TP53 (p53) gene in human lung cancer (data extracted from the IARC TP53 database) and mutations we identified in gpt delta mice showed that G to A transitions centered in CGT and CGG trinucleotides were mutation hotspots on both TP53 genes in human lung cancers and gpt genes in transgenic mice that inhaled diesel exhaust. The carcinogenic potency (TD50 value) of genotoxic carcinogen was shown to be correlated with the in vivo mutagenicity (total dose per increased mutant frequency). These results suggest that the mutations identified in transgenic rodents can help identify environmental mutagens that cause cancer.
Collapse
Affiliation(s)
- Yasunobu Aoki
- National Institute for Environmental Studies, Center for Health and Environmental Risk Research, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 Japan
| |
Collapse
|
3
|
O'Brien JM, Beal MA, Yauk CL, Marchetti F. Benzo(a)pyrene Is Mutagenic in Mouse Spermatogonial Stem Cells and Dividing Spermatogonia. Toxicol Sci 2016; 152:363-71. [PMID: 27208087 PMCID: PMC4960908 DOI: 10.1093/toxsci/kfw088] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Although many environmental agents are established male germ cell mutagens, few are known to induce mutations in spermatogonial stem cells. Stem cell mutations are of great concern because they result in a permanent increase in the number of mutations carried in sperm. We investigated mutation induction during mouse spermatogenesis following exposure to benzo(a)pyrene (BaP). MutaMouse males were given 0, 12.5, 25, 50, or 100 mg/kg bw/day BaP for 28 days by oral gavage. Germ cells were collected from the cauda epididymis and seminiferous tubules 3 days after exposure and from cauda epididymis 42 and 70 days after exposure. This design enabled targeted investigation of effects on post-spermatogonia, dividing spermatogonia, and spermatogonial stem cells, respectively. BaP increased lacZ mutant frequency (MF) in cauda sperm after exposure of dividing spermatogonia (4.2-fold at highest dose, P < .01) and spermatogonial stem cells (2.1-fold at highest dose, P < .01). No significant increases in MF were detected in cauda sperm or seminiferous tubule cells collected 3 days post-exposure. Dose-response modelling suggested that the mutational response in male germ cells to BaP is sub-linear at low doses. Our results demonstrate that oral exposure to BaP causes spermatogonial stem cell mutations, that different phases of spermatogenesis exhibit varying sensitivities to BaP, with dividing spermatogonia representing a window of peak sensitivity, and that sampling spermatogenic cells from the seminiferous tubules at earlier time-points may underestimate germ cell mutagenicity. This information is critical to optimize the use of the international test guideline for transgenic rodent mutation assays for detecting germ cell mutagens.
Collapse
Affiliation(s)
- Jason M O'Brien
- *Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON K1A 0K9, Canada
| | - Marc A Beal
- *Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON K1A 0K9, Canada
| | - Carole L Yauk
- *Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON K1A 0K9, Canada
| | - Francesco Marchetti
- *Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON K1A 0K9, Canada
| |
Collapse
|
4
|
Beal MA, Rowan-Carroll A, Campbell C, Williams A, Somers CM, Marchetti F, Yauk CL. Single-molecule PCR analysis of an unstable microsatellite for detecting mutations in sperm of mice exposed to chemical mutagens. Mutat Res 2015; 775:26-32. [PMID: 25863182 DOI: 10.1016/j.mrfmmm.2015.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/16/2015] [Accepted: 03/22/2015] [Indexed: 12/15/2022]
Abstract
Single-molecule PCR (SM-PCR) analysis of long and repetitive DNA sequences, known as expanded simple tandem repeats (ESTRs), has been the most efficient method for studying germline mutation induction in endogenous sequences to date. However, the long length of these sequences makes mutation detection imprecise and laborious, and they have been characterized only in mice. Here, we explore the use of unstable microsatellite sequences that can be typed with high precision by capillary electrophoresis as alternative loci for detecting germline mutations. We screened 24 microsatellite loci across inbred mouse strains and identified Mm2.2.1 as the most polymorphic microsatellite locus. We then optimized SM-PCR of Mm2.2.1 to detect mutations in sperm. SM-PCR analysis of sperm from untreated B6C3F1 and Muta(™)Mouse samples revealed mutation frequencies that are consistent with rates derived from family pedigree analysis (∼ 5 × 10(-3)). To determine whether this locus can be used to detect chemically induced germline mutations, Muta(™)Mouse males were exposed by oral gavage to a single dose of 100mg/kg of N-ethyl-N-nitrosourea (ENU) or to 100mg/kg of benzo(a)pyrene (BaP) for 28 days alongside vehicle treated controls. Sperm were collected 10 weeks post-ENU exposure to sample sperm exposed as spermatogonial stem cells and 6 weeks post-BaP exposure to sample sperm that were dividing spermatogonia when the exposure was terminated. Both treatments resulted in a significant (approximately 2-fold) increase in mutation frequency in sperm compared to the control animals. The work establishes the utility of this microsatellite for studying mutation induction in the germ cells of mice. Because microsatellites are found in virtually every species, this approach holds promise for other organisms, including humans.
Collapse
Affiliation(s)
- Marc A Beal
- Carleton University, Ottawa, Ontario K1S 5B6, Canada; Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario K1A 0K9, Canada.
| | - Andrea Rowan-Carroll
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario K1A 0K9, Canada.
| | - Caleigh Campbell
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario K1A 0K9, Canada.
| | - Andrew Williams
- 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.
| | - Carole L Yauk
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario K1A 0K9, Canada.
| |
Collapse
|
5
|
Beal MA, Glenn TC, Lance SL, Somers CM. Characterization of unstable microsatellites in mice: no evidence for germline mutation induction following gamma-radiation exposure. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2012; 53:599-607. [PMID: 22930577 DOI: 10.1002/em.21726] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 07/19/2012] [Indexed: 06/01/2023]
Abstract
Large tandem repeat DNA loci such as expanded simple tandem repeats and minisatellites are efficient markers for detecting germline mutations; however, mutation detection using these loci can be imprecise and difficult to standardize across labs. Short-tandem repeats, such as microsatellites, offer more precise and high-throughput mutation detection, but germline mutation induction at these loci has not yet been studied in model organisms such as mice. In this study, we used microsatellite enrichment and large-scale DNA sequencing of several closely related inbred mouse lines to identify a panel of 19 polymorphic microsatellites with potentially high spontaneous mutation frequencies. We used this panel and four additional loci from other sources to quantify spontaneous mutation frequency in pedigrees of outbred Swiss-Webster mice. In addition, we also examined mutation induction in families in which sires were treated with acute doses of either 0.5 Gy or 1.0 Gy gamma-irradiation to spermatogonial stem cells. Per locus mutation frequencies ranged from 0 to 5.03 × 10(-3). Considering only the 11 loci with mutations, the mutation frequencies were: control 2.78 × 10(-3), 0.5 Gy 4.09 × 10(-3), and 1.0 Gy 1.82 × 10(-3). There were no statistically significant changes in mutation frequencies among treatment groups. Our study provides the first direct quantification of microsatellite mutation frequency in the mouse germline, but shows no evidence for mutation induction at pre-meiotic male germ cells following acute gamma-irradiation. Further work using the panel is needed to examine mutation induction at different doses of radiation, exposure durations, and stages during spermatogenesis.
Collapse
Affiliation(s)
- Marc A Beal
- Department of Biology, University of Regina, Regina, Saskatchewan, Canada S4S 0A2
| | | | | | | |
Collapse
|
6
|
Beal MA, Glenn TC, Somers CM. Whole genome sequencing for quantifying germline mutation frequency in humans and model species: cautious optimism. Mutat Res 2012; 750:96-106. [PMID: 22178956 DOI: 10.1016/j.mrrev.2011.11.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 11/29/2011] [Accepted: 11/30/2011] [Indexed: 05/31/2023]
Abstract
Factors affecting the type and frequency of germline mutations in animals are of significant interest from health and toxicology perspectives. However, studies in this field have been limited by the use of markers with low detection power or uncertain relevance to phenotype. Whole genome sequencing (WGS) is now a potential option to directly determine germline mutation type and frequency in family groups at all loci simultaneously. Medical studies have already capitalized on WGS to identify novel mutations in human families for clinical purposes, such as identifying candidate genes contributing to inherited conditions. However, WGS has not yet been used in any studies of vertebrates that aim to quantify changes in germline mutation frequency as a result of environmental factors. WGS is a promising tool for detecting mutation induction, but it is currently limited by several technical challenges. Perhaps the most pressing issue is sequencing error rates that are currently high in comparison to the intergenerational mutation frequency. Different platforms and depths of coverage currently result in a range of 10-10(3) false positives for every true mutation. In addition, the cost of WGS is still relatively high, particularly when comparing mutation frequencies among treatment groups with even moderate sample sizes. Despite these challenges, WGS offers the potential for unprecedented insight into germline mutation processes. Refinement of available tools and emergence of new technologies may be able to provide the improved accuracy and reduced costs necessary to make WGS viable in germline mutation studies in the very near future. To streamline studies, researchers may use multiple family triads per treatment group and sequence a targeted (reduced) portion of each genome with high (20-40 ×) depth of coverage. We are optimistic about the application of WGS for quantifying germline mutations, but caution researchers regarding the resource-intensive nature of the work using existing technology.
Collapse
Affiliation(s)
- Marc A Beal
- University of Regina, Department of Biology, 3737 Wascana Parkway, Regina, Saskatchewan, Canada S4S 0A2
| | - Travis C Glenn
- University of Georgia, Environmental Health Science, College of Public Health, Athens, GA 30602, USA
| | - Christopher M Somers
- University of Regina, Department of Biology, 3737 Wascana Parkway, Regina, Saskatchewan, Canada S4S 0A2.
| |
Collapse
|
7
|
Ben-Shlomo R, Shanas U. Genetic ecotoxicology of asbestos pollution in the house mouse Mus musculus domesticus. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2011; 18:1264-1269. [PMID: 21384142 DOI: 10.1007/s11356-011-0481-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Accepted: 02/11/2011] [Indexed: 05/30/2023]
Abstract
PURPOSE We tested the genetic diversity in wild mice (Mus musculus domesticus) inhabiting the asbestos-polluted area as a model for the long-term mutagenic effect of asbestos. Hazardous effects of deposited asbestos persist in the environment because of low rate of fiber disintegration. The upper layers of the soil in the vicinity of a former asbestos factory are nearly "saturated" with asbestos fibers and dust. Natural populations of mice dwell in this area and are constantly exposed to asbestos fibers. METHODS We measured the microsatellites genetic diversity of wild mice (Mus musculus domesticus) inhabiting the asbestos-polluted area as a model for the long-term mutagenic effect of this environmental toxin. RESULTS The six tested microsatellites were highly polymorphic, revealing 111 different alleles for the two sampled populations. Effective number of alleles was slightly higher in the polluted population relative to the control population, while observed heterozygosity was lower. The chromatographic profile of the polluted population exhibited a significantly higher number of bands, probably resulting from somatic mutations, in addition to the ordinary microsatellite band profiles. CONCLUSIONS Long-term exposure to asbestos fibers significantly elevates the level of somatic mutations. It also leads to a relatively high level of observed homozygosity, a phenomenon that may be associated with loss of heterozygosity. Based on the mice population, our data suggest elevated health risks for humans living in an asbestos-polluted area.
Collapse
Affiliation(s)
- Rachel Ben-Shlomo
- Department of Biology, Faculty of Natural Sciences, University of Haifa-Oranim, Tivon 36006, Israel.
| | | |
Collapse
|
8
|
Somers CM. Ambient air pollution exposure and damage to male gametes: human studies andin situ‘sentinel’ animal experiments. Syst Biol Reprod Med 2011; 57:63-71. [DOI: 10.3109/19396368.2010.500440] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
9
|
Tsyusko O, Glenn T, Yi Y, Joice G, Jones K, Aizawa K, Coughlin D, Zimbrick J, Hinton T. Differential genetic responses to ionizing irradiation in individual families of Japanese medaka, Oryzias latipes. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2011; 718:18-23. [DOI: 10.1016/j.mrgentox.2010.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 10/15/2010] [Accepted: 11/07/2010] [Indexed: 10/18/2022]
|
10
|
Kodaira M, Ryo H, Kamada N, Furukawa K, Takahashi N, Nakajima H, Nomura T, Nakamura N. No Evidence of Increased Mutation Rates at Microsatellite Loci in Offspring of A-Bomb Survivors. Radiat Res 2010; 173:205-13. [DOI: 10.1667/rr1991.1] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- M. Kodaira
- Departments of Genetics and, Radiation Effects Research Foundation, Hiroshima, Japan
| | - H. Ryo
- Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - N. Kamada
- Departments of Statistics and, Radiation Effects Research Foundation, Hiroshima, Japan
| | - K. Furukawa
- Departments of Statistics and, Radiation Effects Research Foundation, Hiroshima, Japan
| | - N. Takahashi
- Departments of Genetics and, Radiation Effects Research Foundation, Hiroshima, Japan
| | - H. Nakajima
- Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - T. Nomura
- Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - N. Nakamura
- Departments of Chief Scientist, Radiation Effects Research Foundation, Hiroshima, Japan
| |
Collapse
|
11
|
Liu YR, Zhou Y, Qiu W, Zeng JY, Shen LL, Li AP, Zhou JW. Exposure to formaldehyde induces heritable DNA mutations in mice. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2009; 72:767-773. [PMID: 19492241 DOI: 10.1080/15287390902841615] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Our recent studies showed that exposure to mixed indoor air pollutants in a newly decorated residential apartment induced expanded simple tandem repeats (ESTR) mutations in mice, and the mutations were mainly inherited from the paternal germ line. Formaldehyde (FA) is a type of major volatile organic chemical (VOC) present in indoor air, and a constituent known to be associated with sick building syndrome. In the present study, mice were exposed to different concentrations of FA (0, 2, 20, or 200 mg/m(3)). The germline mutations were detected in their offspring using three ESTR probes, Ms6-hm, Hm-2, and MMS10. Data indicated that mice exposed to 200 mg/m(3) FA demonstrated a significant elevation in ESTR mutations, which is due primarily to an increase in mutations inherited through the paternal germ line. These results suggest that FA induced ESTR mutations in mice. It is postulated that single FA exposure might be a useful model to identify indoor air mixture exposure-induced heritable DNA damage.
Collapse
Affiliation(s)
- Yun-Ru Liu
- Department of Molecular Cell Biology and Toxicology, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing, People's Republic of China
| | | | | | | | | | | | | |
Collapse
|
12
|
Zhou Y, Liu Y, Qiu W, Zeng J, Chen X, Zhou H, Li A, Zhou J. Exposure to residential indoor air induces heritable DNA mutations in mice. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2009; 72:1561-1566. [PMID: 20077230 DOI: 10.1080/15287390903232442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Exposure to the mixed indoor air pollutants released from synthetic materials and chemical products poses a serious public health problem, but little evidence has been provided to clarify whether such pollutants at environmentally relevant concentrations produce inheritable germline mutations. In the present study, mice were exposed to samples of indoor air from a newly decorated apartment bedroom. Results showed expanded simple tandem repeat (ESTR) mutations occurring in the germline of control and exposed parents, which were also detected in their offspring using three probes, Ms6-hm, Hm-2, and MMS10. Data indicated that mice being exposed to indoor air triggered a significant increase in frequency of ESTR mutations, which may be due primarily to a rise in mutations inherited through the paternal germline. These results suggest that exposure to a mixture of pollutants in indoor air obtained from an apartment in China induced ESTR mutations. Thus, humans exposed to polluted indoor apartment air in China may be at risk for developing germline mutations.
Collapse
Affiliation(s)
- Yin Zhou
- Department of Molecular Cell Biology and Toxicology, School of Public Health, Nanjing Medical University, Nanjing
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Somers CM, Cooper DN. Air pollution and mutations in the germline: are humans at risk? Hum Genet 2008; 125:119-30. [PMID: 19112582 DOI: 10.1007/s00439-008-0613-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Accepted: 12/16/2008] [Indexed: 01/27/2023]
Abstract
Genotoxic air pollution is ubiquitous in urban and industrial areas. A variety of studies has linked human exposure to air pollution with a number of different somatic cell endpoints including cancer. However, the potential for inducing mutations in the human germline remains unclear. Sentinel animal studies of germline mutations at tandem-repeat loci (specifically minisatellites and expanded simple tandem repeats) have recently provided proof of principle that germline mutations can be induced in vertebrates (birds and mice) by air pollution under ambient conditions. Although humans may also be susceptible to induced germline mutations in polluted areas, uncertainties regarding causative agents, doses, and mutational mechanisms at repetitive DNA loci currently preclude extrapolation from animal data to the evaluation of human risk. Nevertheless, several recent studies have linked air pollution exposure to DNA damage in human sperm, indicating that our germ cells are not impervious to the genotoxic effects of air pollution. Thus, both sentinel animal and human studies have raised the possibility that ambient air pollution may increase human germline mutation rates, especially at repetitive DNA loci. Given that some human genetic conditions appear to be modulated by length mutations at tandem-repeat loci (e.g. HRAS1 cancers, type 1 diabetes, etc.), there is an urgent need for extensive study in this area. Research should be primarily focused upon: (1) the direct measurement of mutation frequencies at repetitive DNA loci in human male germ cells as a function of air pollution exposure, (2) large-scale epidemiology studies of inherited disorders and tandem-repeat associated genetic conditions and air pollution, and (3) the characterization of mutational mechanisms at hypervariable tandem-repeat loci.
Collapse
|
14
|
Somers CM, Valdes EV, Kjoss VA, Vaillancourt AL, Quinn JS. Influence of a contaminated fish diet on germline expanded-simple-tandem-repeat mutation frequency in mice. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2008; 49:238-248. [PMID: 18288721 DOI: 10.1002/em.20380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Herring gulls (Larus argentatus) in polluted areas on the North American Great Lakes were previously shown to have elevated germline mutation frequencies at minisatellite DNA loci. Airborne or dietary contaminants likely caused induced mutations, but the importance of each exposure type was unknown. Follow-up experiments with lab mice determined that air pollution significantly induced germline mutations; however, an evaluation of mutations induced by the diet of herring gulls has not yet been conducted. To address this issue, we fed mice a high-fish diet (58% wet mass) of the most common prey species for herring gulls nesting in Hamilton Harbour, a polluted industrial area on Lake Ontario. We bred the mice and screened pedigrees for germline mutations at expanded-simple-tandem-repeat (ESTR) DNA loci. Mutation frequencies were compared to those in a reference group that was fed fish from Atlantic Canada, and a control group that was fed commercial chow. Germline mutation frequencies were highest in mice fed contaminated fish, but were only marginally or not significantly affected by diet treatment. Statistical power to detect differences among treatment groups was low, and the effect of diet may have more clearly emerged if larger sample sizes were available. Levels of organic pollutants in the fish from Hamilton Harbour were higher than those from Atlantic Canada, but their ability to induce ESTR mutations is unknown. Our findings suggest that a contaminated fish diet may contribute to the elevated germline mutation frequencies observed previously in gulls at this site, but air pollution is likely a more important route of exposure.
Collapse
|
15
|
Yauk C, Polyzos A, Rowan-Carroll A, Somers CM, Godschalk RW, Van Schooten FJ, Berndt ML, Pogribny IP, Koturbash I, Williams A, Douglas GR, Kovalchuk O. Germ-line mutations, DNA damage, and global hypermethylation in mice exposed to particulate air pollution in an urban/industrial location. Proc Natl Acad Sci U S A 2008; 105:605-10. [PMID: 18195365 PMCID: PMC2206583 DOI: 10.1073/pnas.0705896105] [Citation(s) in RCA: 205] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Indexed: 11/18/2022] Open
Abstract
Particulate air pollution is widespread, yet we have little understanding of the long-term health implications associated with exposure. We investigated DNA damage, mutation, and methylation in gametes of male mice exposed to particulate air pollution in an industrial/urban environment. C57BL/CBA mice were exposed in situ to ambient air near two integrated steel mills and a major highway, alongside control mice breathing high-efficiency air particulate (HEPA) filtered ambient air. PCR analysis of an expanded simple tandem repeat (ESTR) locus revealed a 1.6-fold increase in sperm mutation frequency in mice exposed to ambient air for 10 wks, followed by a 6-wk break, compared with HEPA-filtered air, indicating that mutations were induced in spermatogonial stem cells. DNA collected after 3 or 10 wks of exposure did not exhibit increased mutation frequency. Bulky DNA adducts were below the detection threshold in testes samples, suggesting that DNA reactive chemicals do not reach the germ line and cause ESTR mutation. In contrast, DNA strand breaks were elevated at 3 and 10 wks, possibly resulting from oxidative stress arising from exposure to particles and associated airborne pollutants. Sperm DNA was hypermethylated in mice breathing ambient relative to HEPA-filtered air and this change persisted following removal from the environmental exposure. Increased germ-line DNA mutation frequencies may cause population-level changes in genetic composition and disease. Changes in methylation can have widespread repercussions for chromatin structure, gene expression and genome stability. Potential health effects warrant extensive further investigation.
Collapse
Affiliation(s)
- Carole Yauk
- Environmental and Occupational Toxicology Division, HECSB, Ottawa, ON, Canada K1A 0K9.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Wyrobek AJ, Mulvihill JJ, Wassom JS, Malling HV, Shelby MD, Lewis SE, Witt KL, Preston RJ, Perreault SD, Allen JW, DeMarini DM, Woychik RP, Bishop JB. Assessing human germ-cell mutagenesis in the Postgenome Era: a celebration of the legacy of William Lawson (Bill) Russell. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2007; 48:71-95. [PMID: 17295306 PMCID: PMC2071946 DOI: 10.1002/em.20284] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Birth defects, de novo genetic diseases, and chromosomal abnormality syndromes occur in approximately 5% of all live births, and affected children suffer from a broad range of lifelong health consequences. Despite the social and medical impact of these defects, and the 8 decades of research in animal systems that have identified numerous germ-cell mutagens, no human germ-cell mutagen has been confirmed to date. There is now a growing consensus that the inability to detect human germ-cell mutagens is due to technological limitations in the detection of random mutations rather than biological differences between animal and human susceptibility. A multidisciplinary workshop responding to this challenge convened at The Jackson Laboratory in Bar Harbor, Maine. The purpose of the workshop was to assess the applicability of an emerging repertoire of genomic technologies to studies of human germ-cell mutagenesis. Workshop participants recommended large-scale human germ-cell mutation studies be conducted using samples from donors with high-dose exposures, such as cancer survivors. Within this high-risk cohort, parents and children could be evaluated for heritable changes in (a) DNA sequence and chromosomal structure, (b) repeat sequences and minisatellites, and (c) global gene expression profiles and pathways. Participants also advocated the establishment of a bio-bank of human tissue samples from donors with well-characterized exposure, including medical and reproductive histories. This mutational resource could support large-scale, multiple-endpoint studies. Additional studies could involve the examination of transgenerational effects associated with changes in imprinting and methylation patterns, nucleotide repeats, and mitochondrial DNA mutations. The further development of animal models and the integration of these with human studies are necessary to provide molecular insights into the mechanisms of germ-cell mutations and to identify prevention strategies. Furthermore, scientific specialty groups should be convened to review and prioritize the evidence for germ-cell mutagenicity from common environmental, occupational, medical, and lifestyle exposures. Workshop attendees agreed on the need for a full-scale assault to address key fundamental questions in human germ-cell environmental mutagenesis. These include, but are not limited to, the following: Do human germ-cell mutagens exist? What are the risks to future generations? Are some parents at higher risk than others for acquiring and transmitting germ-cell mutations? Obtaining answers to these, and other critical questions, will require strong support from relevant funding agencies, in addition to the engagement of scientists outside the fields of genomics and germ-cell mutagenesis.
Collapse
Affiliation(s)
| | - John J. Mulvihill
- University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - John S. Wassom
- YAHSGS, LLC, Richland, Washington
- Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Heinrich V. Malling
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Michael D. Shelby
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | | | - Kristine L. Witt
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - R. Julian Preston
- US Environmental Protection Agency, Research Triangle Park, North Carolina
| | - Sally D. Perreault
- US Environmental Protection Agency, Research Triangle Park, North Carolina
| | - James W. Allen
- US Environmental Protection Agency, Research Triangle Park, North Carolina
| | - David M. DeMarini
- US Environmental Protection Agency, Research Triangle Park, North Carolina
| | | | - Jack B. Bishop
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
- *Correspondence to: Dr. Jack B. Bishop, National Institute of Environmental Health Sciences, EC-01, PO Box 12233, Research Triangle Park, North Carolina, USA. E-mail:
| | | |
Collapse
|
17
|
Perrin J, Lussato D, De Méo M, Durand P, Grillo JM, Guichaoua MR, Botta A, Bergé-Lefranc JL. Evolution of DNA strand-breaks in cultured spermatocytes: The Comet Assay reveals differences in normal and γ-irradiated germ cells. Toxicol In Vitro 2007; 21:81-9. [PMID: 17055212 DOI: 10.1016/j.tiv.2006.08.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Revised: 08/09/2006] [Accepted: 08/30/2006] [Indexed: 11/29/2022]
Abstract
In reproductive toxicity assessment, in vitro systems can be used to determine mechanisms of action of toxicants. However, they generally investigate the immediate effects of toxicants, on isolated germ cells or spermatozoa. We report here the usefulness of in vitro cultures of rat spermatocytes and Sertoli cells, in conjunction with the Comet Assay to analyze the evolution of DNA strand-breaks and thus to determine DNA damage in germ cells. We compared cultures of normal and gamma-irradiated germ cells. In non-irradiated spermatocytes, the Comet Assay revealed the presence of DNA strand-breaks, which numbers decreased with the duration of the culture, suggesting the involvement of DNA repair mechanisms related to the meiotic recombination. In irradiated cells, the evolution of DNA strand-breaks was strongly modified. Thus our model is able to detect genotoxic lesions and/or DNA repair impairment in cultured spermatocytes. We propose this model as an in vitro tool for the study of genotoxic injuries on spermatocytes.
Collapse
Affiliation(s)
- J Perrin
- IFR PMSE 112 (Pôle Méditerranéen des Sciences de l'Environnement), Facultés de Médecine et de Pharmacie, Université de la Méditerranée, 27 Boulevard Jean Moulin, 13385 Marseille Cedex 05, France.
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Gomes-Pereira M, Monckton DG. Chemical modifiers of unstable expanded simple sequence repeats: what goes up, could come down. Mutat Res 2006; 598:15-34. [PMID: 16500684 DOI: 10.1016/j.mrfmmm.2006.01.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A mounting number of inherited human disorders, including Huntington disease, myotonic dystrophy, fragile X syndrome, Friedreich ataxia and several spinocerebellar ataxias, have been associated with the expansion of unstable simple sequence DNA repeats. Despite a similar genetic basis, pathogenesis in these disorders is mediated by a variety of both loss and gain of function pathways. Thus, therapies targeted at downstream pathology are likely to be disease specific. Characteristically, disease-associated expanded alleles in these disorders are highly unstable in the germline and somatic cells, with a tendency towards further expansion. Whereas germline expansion accounts for the phenomenon of anticipation, tissue-specific, age-dependent somatic expansion may contribute towards the tissue-specificity and progressive nature of the symptoms. Thus, somatic expansion presents as a novel therapeutic target in these disorders. Suppression of somatic expansion should be therapeutically beneficial, whilst reductions in repeat length could be curative. It is well established that both cis- and trans-acting genetic modifiers play key roles in the control of repeat dynamics. Importantly, recent data have revealed that expanded CAG.CTG repeats are also sensitive to a variety of trans-acting chemical modifiers. These data provide an exciting proof of principle that drug induced suppression of somatic expansion might indeed be feasible. Moreover, as our understanding of the mechanism of expansion is refined more rational approaches to chemical intervention in the expansion pathway can be envisioned. For instance, the demonstration that expansion of CAG.CTG repeats is dependent on the Msh2, Msh3 and Pms2 genes, highlights components of the DNA mismatch repair pathway as therapeutic targets. In addition to potential therapeutic applications, the response of expanded simple repeats to genotoxic assault suggests such sequences could also have utility as bio-monitors of environmentally induced genetic damage in the soma.
Collapse
Affiliation(s)
- Mário Gomes-Pereira
- Inserm U383, Clinique Maurice Lamy, Hôpital Necker Enfants Malades, 149 rue de Sèvres, 75015 Paris, France
| | | |
Collapse
|