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Langlois VS, Plante I, Vaudin P, Martyniuk CJ. Twenty-five years beyond "Our Stolen Future": How did we progress as an international society on screening and regulating Endocrine Disrupting Chemicals (EDCs)? Environ Res 2022; 210:112849. [PMID: 35120892 DOI: 10.1016/j.envres.2022.112849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Affiliation(s)
- V S Langlois
- Institut National de la recherche scientifique (INRS), Centre Eau Terre Environnement, Quebec City, QC, Canada.
| | - I Plante
- Institut National de la recherche scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Laval, QC, Canada
| | - P Vaudin
- Physiologie de la Reproduction et des Comportements, CNRS, IFCE, INRAE, Université de Tours, PRC, F-37380, Nouzilly, France
| | - C J Martyniuk
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences in Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
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Marlatt VL, Bayen S, Castaneda-Cortès D, Delbès G, Grigorova P, Langlois VS, Martyniuk CJ, Metcalfe CD, Parent L, Rwigemera A, Thomson P, Van Der Kraak G. Impacts of endocrine disrupting chemicals on reproduction in wildlife and humans. Environ Res 2022; 208:112584. [PMID: 34951986 DOI: 10.1016/j.envres.2021.112584] [Citation(s) in RCA: 54] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 06/14/2023]
Abstract
Endocrine disrupting chemicals (EDCs) are ubiquitous in aquatic and terrestrial environments. The main objective of this review was to summarize the current knowledge of the impacts of EDCs on reproductive success in wildlife and humans. The examples selected often include a retrospective assessment of the knowledge of reproductive impacts over time to discern how the effects of EDCs have changed over the last several decades. Collectively, the evidence summarized here within reinforce the concept that reproduction in wildlife and humans is negatively impacted by anthropogenic chemicals, with several altering endocrine system function. These observations of chemicals interfering with different aspects of the reproductive endocrine axis are particularly pronounced for aquatic species and are often corroborated by laboratory-based experiments (i.e. fish, amphibians, birds). Noteworthy, many of these same indicators are also observed in epidemiological studies in mammalian wildlife and humans. Given the vast array of reproductive strategies used by animals, it is perhaps not surprising that no single disrupted target is predictive of reproductive effects. Nevertheless, there are some general features of the endocrine control of reproduction, and in particular, the critical role that steroid hormones play in these processes that confer a high degree of susceptibility to environmental chemicals. New research is needed on the implications of chemical exposures during development and the potential for long-term reproductive effects. Future emphasis on field-based observations that can form the basis of more deliberate, extensive, and long-term population level studies to monitor contaminant effects, including adverse effects on the endocrine system, are key to addressing these knowledge gaps.
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Affiliation(s)
- V L Marlatt
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
| | - S Bayen
- Department of Food Science and Agricultural Chemistry, McGill University, Montreal, QC, Canada
| | - D Castaneda-Cortès
- Centre Eau Terre Environnement, Institut National de la Recherche Scientifique (INRS), Laval, QC, Canada
| | - G Delbès
- Centre Armand Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, QC, Canada
| | - P Grigorova
- Département Science et Technologie, Université TELUQ, Montréal, QC, Canada
| | - V S Langlois
- Centre Eau Terre Environnement, Institut National de la Recherche Scientifique (INRS), Laval, QC, Canada
| | - C J Martyniuk
- Center for Environmental and Human Toxicology, Department of Physiological Sciences, University of Florida, Gainesville, FL, United States
| | - C D Metcalfe
- School of Environment, Trent University, Trent, Canada
| | - L Parent
- Département Science et Technologie, Université TELUQ, Montréal, QC, Canada
| | - A Rwigemera
- Centre Armand Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, QC, Canada
| | - P Thomson
- Centre Eau Terre Environnement, Institut National de la Recherche Scientifique (INRS), Laval, QC, Canada
| | - G Van Der Kraak
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
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Shen L, Estrada AH, Meurs KM, Sleeper M, Vulpe C, Martyniuk CJ, Pacak CA. A review of the underlying genetics and emerging therapies for canine cardiomyopathies. J Vet Cardiol 2021; 40:2-14. [PMID: 34147413 DOI: 10.1016/j.jvc.2021.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 10/21/2022]
Abstract
Cardiomyopathies such as dilated cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy are common in large breed dogs and carry an overall poor prognosis. Research shows that these diseases have strong breed predilections, and selective breeding has historically been recommended to reduce the disease prevalence in affected breeds. Treatment of these diseases is typically palliative and aimed at slowing disease progression and managing clinical signs of heart failure as they develop. The discovery of specific genetic mutations underlying cardiomyopathies, such as the striatin mutation in Boxer arrhythmogenic right ventricular cardiomyopathy and the pyruvate dehydrogenase kinase 4 and titin mutations in Doberman Pinschers, has strengthened our ability to screen and selectively breed individuals in an attempt to produce unaffected offspring. The discovery of these disease-linked mutations has also opened avenues for the development of gene therapies, including gene transfer and genome-editing approaches. This review article discusses the known genetics of cardiomyopathies in dogs, reviews existing gene therapy strategies and the status of their development in canines, and discusses ongoing challenges in the clinical translation of these technologies for treating heart disease. While challenges remain in using these emerging technologies, the exponential growth of the gene therapy field holds great promise for future clinical applications.
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Affiliation(s)
- L Shen
- Program for Applied Research and Development in Genomic Medicine, College of Pharmacy, University of Florida, 1225 Center Drive, Gainesville, FL, 32610, USA.
| | - A H Estrada
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, PO Box 100136, Gainesville, FL, 32610, USA
| | - K M Meurs
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, 27607, USA
| | - M Sleeper
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, PO Box 100136, Gainesville, FL, 32610, USA
| | - C Vulpe
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, 1333 Center Dr, Gainesville, FL, 32603, USA
| | - C J Martyniuk
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, 1333 Center Dr, Gainesville, FL, 32603, USA
| | - C A Pacak
- Department of Neurology, College of Medicine, University of Minnesota, 516 Delaware Street SE, Minneapolis, MN, 55455, USA
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Marjan P, Bragg LM, MacLatchy DL, Servos MR, Martyniuk CJ. How Does Reference Site Selection Influence Interpretation of Omics Data?: Evaluating Liver Transcriptome Responses in Male Rainbow Darter (Etheostoma caeruleum) across an Urban Environment. Environ Sci Technol 2017; 51:6470-6479. [PMID: 28489360 DOI: 10.1021/acs.est.7b00894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Studies quantifying the influence of reference site selection on transcriptomic profiles in aquatic organisms exposed to complex mixtures are lacking in the literature, despite the significant implications of such research for the interpretation of omics data sets. We measured hepatic transcriptomic responses in fish across an urban environment in the central Grand River watershed (Ontario, Canada). Adult male rainbow darter (RBD) (Etheostoma caeruleum) were collected from nine sites at varying distances from two major municipal wastewater treatment plants (MWWTPs) (Waterloo, Kitchener), including three upstream reference sites. The transcriptomic response in RBD was independently compared with that of fish from each of the three reference sites. Data collected in fish downstream of the Waterloo MWWTP (poorest effluent quality) suggested that ∼15.5% of the transcriptome response was influenced by reference site selection. In contrast, at sites where the impact of MWWTPs was less-pronounced and fish showed less of a transcriptome response, reference site selection had a greater influence (i.e., ∼56.9% of transcripts were different depending on the site used). This study highlights the importance of conducting transcriptomics studies that leverage more than one reference site, and it broadens our understanding of the molecular responses in fish in dynamic natural environments.
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Affiliation(s)
- Patricija Marjan
- Department of Biology, University of Waterloo , 200 University Avenue West, N2L 3G1 Waterloo, Ontario, Canada
| | - Leslie M Bragg
- Department of Biology, University of Waterloo , 200 University Avenue West, N2L 3G1 Waterloo, Ontario, Canada
| | - Deborah L MacLatchy
- Department of Biology, Wilfrid Laurier University , 75 University Avenue West, N2L 3C5 Waterloo, Ontario, Canada
| | - Mark R Servos
- Department of Biology, University of Waterloo , 200 University Avenue West, N2L 3G1 Waterloo, Ontario, Canada
| | - Cristopher J Martyniuk
- Center for Environmental and Human Toxicology & Department of Physiological Sciences, University of Florida , 2187 Mowry Road, Building 471, PO Box 110885, Gainesville, Florida 32611, United States
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Bahamonde PA, Fuzzen ML, Bennett CJ, Tetreault GR, McMaster ME, Servos MR, Martyniuk CJ, Munkittrick KR. Whole organism responses and intersex severity in rainbow darter (Etheostoma caeruleum) following exposures to municipal wastewater in the Grand River basin, ON, Canada. Part A. Aquat Toxicol 2015; 159:290-301. [PMID: 25543172 DOI: 10.1016/j.aquatox.2014.11.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 11/24/2014] [Accepted: 11/25/2014] [Indexed: 06/04/2023]
Abstract
Municipal wastewater effluents (MWWEs) contain anthropogenic substances that can exhibit endocrine-disrupting activity. These complex mixtures have been observed to exert adverse effects on fish. Rainbow darter (Etheostoma caeruleum, RBD) is a small benthic fish that is widespread throughout the Grand River, Ontario, Canada, and has been previously shown to be adversely affected by MWWE exposure in this watershed. The objectives of this study were to quantify biological responses in this sentinel species and intersex severity in male fish, in relation to the area of urbanization. It focused on RBD populations adjacent to wastewater outfalls in the Grand River watershed. In May 2011, nine sites across the urban gradient were selected to evaluate the impact of MWWEs. Endpoints for energy storage (i.e. condition factor, k; liversomatic index, LSI) as well as reproductive endpoints (i.e. gonadosomatic index, GSI; gonad development, hormone production), and intersex were assessed in the fish. Rainbow darter showed a high incidence of intersex downstream of the wastewater outfalls, especially below the largest treatment plant outfall at Kitchener (∼85%). We applied an intersex index (score from 0 to 7) that considers the number of eggs within the testis and the stage of maturation of the egg. RBD exposed downstream of the largest wastewater outfall at Kitchener had a score of 3.81±0.37 compared to upstream to the urban areas where there were no intersex males found other than a single individual with a score 1 (average intersex score of site 0.06±0.06). In addition, several fish associated with the Kitchener outfall had macroscopic vitellogenic eggs in the testes (intersex scores 5 and 6). The sub-population of fish located at the wastewater outfall also showed a tendency towards skewed sex ratios (greater proportion of females to male fish) compared to the population at the reference sites. Male fish inhabiting the urbanized area of the Grand River also showed reduced levels of testosterone (T) and 11-ketotestosterone (11KT). Intersex males had the lower levels of 11KT relative to the upstream reference fish but could not be distinguished from normal males collected at the exposed sites. Despite the high levels of intersex at these sites, no relationships were evident among intersex severity and other measured endpoints such as GSI, LSI or in vitro steroid production. The effects observed appear to be associated with urbanization and exposure to treated MWWEs in the watershed. Although intersex incidence and severity was a very good indicator of wastewater exposure, intersex could not be directly linked to other effects in this wild population. The effects of MWWEs on transcriptional changes in adult RBD exposed to the effluents are reported in the corresponding report (Part B).
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Affiliation(s)
- P A Bahamonde
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, NB E2L 4L5, Canada.
| | - M L Fuzzen
- Canadian Rivers Institute and Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - C J Bennett
- Emerging Methods Branch, Aquatic Contaminant Research Division, Water Science and Technology Directorate, Environment Canada, Burlington, ON L7R 4A6, Canada
| | - G R Tetreault
- Emerging Methods Branch, Aquatic Contaminant Research Division, Water Science and Technology Directorate, Environment Canada, Burlington, ON L7R 4A6, Canada
| | - M E McMaster
- Emerging Methods Branch, Aquatic Contaminant Research Division, Water Science and Technology Directorate, Environment Canada, Burlington, ON L7R 4A6, Canada
| | - M R Servos
- Canadian Rivers Institute and Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - C J Martyniuk
- Current address: Center for Environmental and Human Toxicology and the Department of Physiological Sciences, University of Florida Genetics Institute, Gainesville, FL 32611, USA
| | - K R Munkittrick
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, NB E2L 4L5, Canada
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Bahamonde PA, McMaster ME, Servos MR, Martyniuk CJ, Munkittrick KR. Molecular pathways associated with the intersex condition in rainbow darter (Etheostoma caeruleum) following exposures to municipal wastewater in the Grand River basin, ON, Canada. Part B. Aquat Toxicol 2015; 159:302-316. [PMID: 25542366 DOI: 10.1016/j.aquatox.2014.11.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 11/24/2014] [Accepted: 11/25/2014] [Indexed: 06/04/2023]
Abstract
Rainbow darter (Etheostoma caeruleum; RBD) is a small benthic fish found in North America. This species is sensitive to sewage effluent, and intersex is found in up to 80% of males in near-field areas in the Grand River, Ontario, Canada. To learn more about the molecular signaling cascades associated with intersex, a developed customized oligonucleotide microarray (4×180 K) using next generation sequencing was developed to characterize the transcriptome in the gonad of male and female RBD. Gene expression profiling was performed in males and females from both a reference site and a polluted site. Males with and without intersex condition from the areas closest to effluent outfalls were compared to males and females from a reference site. Microarray analysis revealed that there was increased mRNA abundance for genes associated with oogenesis in intersex males (i.e. the presence of eggs within the testis), and a decrease in mRNA abundance for genes associated with spermatid development. In females exposed to effluent, cell processes related with hatching and ovulation were down-regulated, and genes involved in immune responses were increased in abundance. In the non-intersex males exposed to effluent, cell processes such as sperm cell adhesion were decreased at the transcript level relative to males from the reference site. Microarray analysis revealed that heat shock proteins (HSP) were significantly increased in non-intersex males exposed to effluent; however, HSPs were not differentially expressed in intersex males exposed to the effluent. Genes involved in sex differentiation (sox9, foxl2 and dmrt1) and reproduction (esr1, esrb, ar, vtg, cyp19a1 and cyp11a) were measured in males, females, and intersex individuals. Consistent with the intersex condition, many transcripts showed an intermediate expression level in intersex males when compared to phenotypic males and females. This study improves our knowledge regarding the molecular pathways that underlie the intersex condition and develops a suite of qPCR bioassays in RBD that are able to discriminate pollutant-exposed males without intersex from those males with intersex. Part A of this study reports on the effects of municipal wastewater effluents (MWWEs) on RBD in the Grand River and demonstrates that there are disruptions in higher level endpoints that include altered steroid levels. Here we develop a new tool for assessing and monitoring the intersex condition in RBD in polluted natural environments and begin to characterize gene networks that are associated with the condition.
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Affiliation(s)
- P A Bahamonde
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, NB, Canada E2L 4L5.
| | - M E McMaster
- Emerging Methods Branch, Aquatic Contaminant Research Division, Water Science and Technology Directorate, Environment Canada, Burlington, ON, Canada L7R 4A6
| | - M R Servos
- Canadian Rivers Institute and University of Waterloo, Department of Biology, Waterloo, ON, Canada N2L 3G1
| | - C J Martyniuk
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, NB, Canada E2L 4L5
| | - K R Munkittrick
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, NB, Canada E2L 4L5
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Feswick A, Ings JS, Doyle MA, Bosker T, Munkittrick KR, Martyniuk CJ. Transcriptomics profiling and steroid production in mummichog (Fundulus heteroclitus) testes after treatment with 5α-dihydrotestosterone. Gen Comp Endocrinol 2014; 203:106-19. [PMID: 24447443 DOI: 10.1016/j.ygcen.2014.01.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 12/20/2013] [Accepted: 01/08/2014] [Indexed: 01/08/2023]
Abstract
5α-Dihydrotestosterone (DHT) is a potent androgen in mammals with multiple roles; however the physiological actions of DHT in male fishes are not well known. To address this knowledge gap, male mummichog (Fundulus heteroclitus) were continuously exposed to 0, 5, and 50 μg/L DHT for 21 days. Following exposure, testes were separated for histology, ex vivo incubation to measure steroidogenic capacity, and gene expression analyses (real-time PCR and microarray). DHT significantly decreased ex vivo 11-ketotestosterone (11KT) production in males exposed to 50 μg/L DHT but not 5 μg/L DHT, and DHT exposure did not affect ex vivo testosterone production. Histological examination revealed that the amount of interlobular and connective tissue present in the testes was increased in the 50 μg/L DHT treatment. Despite reductions in the production of 11KT, DHT did not affect the expression of targeted genes in the steroidogenic pathway such as steroidogenic acute regulatory protein (star), P450 side chain cleavage (cyp11a1) and 11β-hydroxysteroid dehydrogenase (hsd11b3). Microarray analysis in the testes of individuals from control and 50 μg/L DHT revealed that males exposed to 50 μg/L DHT showed regulated transcriptional sub-networks that were related to immunity, regulation of blood flow, lipids and xenobiotic clearance, suggesting that DHT may be involved in the physiological regulation of these processes in the fish testes. A second objective of this study was to determine the feasibility of measuring mRNA levels in tissues used for ex vivo steroid production by comparing RNA integrity and transcript levels in testes of both immediately flash frozen tissue and incubated tissue. There was no significant difference in RNA quality between the two time points, indicating RNA integrity can remain intact for at least 18 h in ex vivo assays, thereby providing a viable option for researchers assessing multi-level biological reproductive endpoints when limited tissue is available. While the gene expression levels of actb, efla, rps12, rps18, star, and hsd11b3 remained unchanged, esr2a (esrba), esr2b (esrbb) and cyp11a1 were significantly lower in incubated tissue compared to flash frozen tissue. Therefore caution must be used as the steady-state levels of select genes may change over time. This study improves our understanding of DHT action in the teleostean testis and generates new hypotheses regarding cell processes that are regulated by this underexplored and potent androgen.
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Affiliation(s)
- A Feswick
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, New Brunswick E2L 4L5, Canada
| | - J S Ings
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, New Brunswick E2L 4L5, Canada
| | - M A Doyle
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, New Brunswick E2L 4L5, Canada
| | - T Bosker
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, New Brunswick E2L 4L5, Canada
| | - K R Munkittrick
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, New Brunswick E2L 4L5, Canada
| | - C J Martyniuk
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, New Brunswick E2L 4L5, Canada.
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Bahamonde PA, Tetreault GR, McMaster ME, Servos MR, Martyniuk CJ, Munkittrick KR. Molecular signatures in rainbow darter (Etheostoma caeruleum) inhabiting an urbanized river reach receiving wastewater effluents. Aquat Toxicol 2014; 148:211-220. [PMID: 24513783 DOI: 10.1016/j.aquatox.2014.01.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 01/07/2014] [Accepted: 01/10/2014] [Indexed: 06/03/2023]
Abstract
Rainbow darter (Etheostoma caeruleum) is a small benthic fish species found in North America that are abundant and distributed throughout the Grand River watershed, ON, Canada. Rainbow darter exhibit intersex in males at sites adjacent to municipal wastewater effluents (MWWE). In October 2010, female and male rainbow darter were collected at 3 sites (1 upstream reference and 2 downstream exposed sites) in the Grand River near the cities of Kitchener and Waterloo. The primary objectives of this research were (1) to characterize the responses of whole organism endpoints (i.e. condition factor (K), liversomatic (LSI) and gonadosomatic index (GSI), histopathology) to MWWEs and (2) to identify transcripts showing altered steady state abundance with exposure to MWWE in fish inhabiting municipal wastewater effluent-exposed areas. Genes measured in this study included vitellogenin, Sry-box containing protein 9 (sox9), forkhead box L2 (foxl2), doublesex and mab-3 related transcription factor 1 (dmrt1), cytochrome P450, family 11, subfamily A, polypeptide 1 (cyp11a) as well as estrogen (esr1, esrb) and androgen (ar) receptors. There were no changes in condition factor; however, there was a significant increase in LSI and a decrease in GSI in fish inhabiting downstream environments when compared with fish collected from the reference site. Males had a high incidence (∼ 70%) of intersex in downstream sites; characterized by the presence of oocytes within the testis. In the gonad, there were sex specific differences for genes related to sexual differentiation; dmrt1 was only expressed in males whereas foxl2 and sox9 were highly expressed in females compared to males. Expression levels of ar and esr1 were higher in females than males. Conversely, esrb was not differentially expressed between sexes or among sites. There were no differences detected for the genes investigated within sex among sites. This study is the first to report on gene expression changes in the rainbow darter, with emphasis on the differences in transcript abundance between sexes and how these changes relate to exposures to MWWEs. Molecular approaches are being investigated for their potential application to field ecotoxicology, and molecular bioassays for relevant, sentinel species in environmental monitoring programs are required to better understand the impact of anthropogenic impacts on species at risk in river systems.
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Affiliation(s)
- P A Bahamonde
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, NB, Canada E2L 4L5.
| | - G R Tetreault
- Emerging Methods Branch, Aquatic Contaminant Research Division, Water Science and Technology Directorate, Environment Canada, Burlington, ON, Canada L7R 4A6; University of Waterloo, Department of Biology, Waterloo, ON, Canada N2L 3G1
| | - M E McMaster
- Emerging Methods Branch, Aquatic Contaminant Research Division, Water Science and Technology Directorate, Environment Canada, Burlington, ON, Canada L7R 4A6
| | - M R Servos
- University of Waterloo, Department of Biology, Waterloo, ON, Canada N2L 3G1
| | - C J Martyniuk
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, NB, Canada E2L 4L5
| | - K R Munkittrick
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, NB, Canada E2L 4L5
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Doyle MA, Bosker T, Martyniuk CJ, Maclatchy DL, Munkittrick KR. The effects of 17-α-ethinylestradiol (EE2) on molecular signaling cascades in mummichog (Fundulus heteroclitus). Aquat Toxicol 2013; 134-135:34-46. [PMID: 23542652 DOI: 10.1016/j.aquatox.2013.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 02/25/2013] [Accepted: 03/01/2013] [Indexed: 06/02/2023]
Abstract
Exposures to ≤10 ng/L of 17-α-ethinylestradiol (EE2) will reduce or shut down egg production in freshwater fish models, while mummichog (Fundulus heteroclitus), an estuarine species, are able to produce eggs at EE2 concentrations >3000 ng/L. The objective of this study was to gain mechanistic insight into how mummichog are able to produce eggs during exposures to high EE2. Mummichog were exposed to 0, 50 or 250 ng/L of EE2 for 14 d. There were no changes in gonadosomatic index, liversomatic index, gonad development, or plasma estradiol levels after exposure to EE2. However, testosterone significantly decreased with EE2 exposures (50, 250 ng/L). Microarray analysis in the liver revealed that cell processes associated with lipids were affected by EE2 at the transcriptome level. Based on the transcriptomics data, we hypothesize that mummichog are able to maintain lipid transport and uptake into the ovary and this may be associated with apolipoproteins, facilitating normal oocyte development. Novel gene regulatory networks for protein modification targets were also constructed to learn more about the potential roles of estrogens in the teleost liver. Although post-translational modifications (PTMs) are important regulatory mechanisms, the roles of PTMs in protein regulation in fish and the susceptibility of PTMs to aquatic pollutants are largely unexplored and may offer novel insight into mechanisms of endocrine disruption.
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Affiliation(s)
- M A Doyle
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, New Brunswick E2L 4L5, Canada
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Marlatt VL, Martyniuk CJ, Zhang D, Xiong H, Watt J, Xia X, Moon T, Trudeau VL. Auto-regulation of estrogen receptor subtypes and gene expression profiling of 17beta-estradiol action in the neuroendocrine axis of male goldfish. Mol Cell Endocrinol 2008; 283:38-48. [PMID: 18083300 DOI: 10.1016/j.mce.2007.10.013] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Revised: 10/28/2007] [Accepted: 10/31/2007] [Indexed: 11/30/2022]
Abstract
Auto-regulation of the three goldfish estrogen receptor (ER) subtypes was examined simultaneously in multiple tissues, in relation to mRNA levels of liver vitellogenin (VTG) and brain transcripts. Male goldfish were implanted with a silastic implant containing either no steroid or 17beta-estradiol (E2) (100 microg/g body mass) for one and seven days. Liver transcript levels of ERalpha were the most highly up-regulated of the ERs, and a parallel induction of liver VTG was observed. In the testes (7d) and telencephalon (7d), E2 induced ERalpha. In the liver (1d) and hypothalamus (7d) ERbeta1 was down-regulated, while ERbeta2 remained unchanged under all conditions. Although aromatase B levels increased in the brain, the majority of candidate genes identified by microarray in the hypothalamus (1d) decreased. These results demonstrate that ER subtypes are differentially regulated by E2, and several brain transcripts decrease upon short-term elevation of circulating E2 levels.
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Affiliation(s)
- V L Marlatt
- Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5.
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Martyniuk CJ, Chang JP, Trudeau VL. The effects of GABA agonists on glutamic acid decarboxylase, GABA-transaminase, activin, salmon gonadotrophin-releasing hormone and tyrosine hydroxylase mRNA in the goldfish (Carassius auratus) neuroendocrine brain. J Neuroendocrinol 2007; 19:390-6. [PMID: 17425614 DOI: 10.1111/j.1365-2826.2007.01543.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
GABA plays a pivotal role in reproduction by regulating luteinising hormone (LH) release from the anterior pituitary. Current evidence indicates that there is a prominent stimulatory effect of GABA on LH release in teleost fish which results from enhanced gonadotrophin-releasing hormone (GnRH) release and decreased dopamine turnover in the brain and pituitary. We hypothesised that there may be additional mechanisms underlying LH release in goldfish and investigated the relative mRNA levels of GABA synthesising enzymes (GAD65 and GAD67), degrading enzyme (GABA-T), activin betaa and betab, salmon GnRH (sGnRH), and tyrosine hydroxylase (TH) with the real-time reverse transcriptase-polymerase chain reaction after GABA agonist treatment. Sexually regressed female goldfish were i.p. injected with either the GABA(A) agonist muscimol (1 microg/g body weight) or the GABA(B) agonist baclofen (10 microg/g body weight). Both agonists significantly increased serum LH after 6 h. Muscimol decreased GAD65 (approximately ten-fold), GABA-T (approximately 15-fold) and TH (approximately three-fold) mRNA in the telencephalon. Baclofen significantly reduced GAD67 (approximately two-fold) and GABA-T (approximately two-fold) mRNA levels in the hypothalamus. Activin betaa, but not activin betab, steady-state mRNA was increased approximately three- to four-fold in both the hypothalamus and telencephalon after baclofen treatment. There was no change in sGnRH mRNA levels in either tissue after GABA agonist treatment. We show that the GABA(A) and GABA(B) receptor agonists have differing and rapid effects on gene transcription in the goldfish neuroendocrine brain and, by affecting specific targets, we identify putative genomic mechanisms underlying GABA-stimulated LH release in fish.
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Affiliation(s)
- C J Martyniuk
- Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
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Martyniuk CJ, Crawford AB, Hogan NS, Trudeau VL. GABAergic modulation of the expression of genes involved in GABA synaptic transmission and stress in the hypothalamus and telencephalon of the female goldfish (Carassius auratus). J Neuroendocrinol 2005; 17:269-75. [PMID: 15869561 DOI: 10.1111/j.1365-2826.2005.01311.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
GABA is one of the most abundant neurotransmitters in the vertebrate central nervous system and is involved in neuroendocrine processes such as development, reproduction, feeding and stress. To examine the effect of GABA on gene expression in the brain, we used a cDNA macroarray containing 26 genes involved in GABA synaptic transmission (GABA receptor subunits, GABA transporters), reproduction (gonadotrophin-releasing hormone isoforms and oestrogen receptor alpha), feeding (neuropeptide Y and cholecystokinin), and stress [corticotrophin-releasing factor (CRF)]. To elevate GABA levels in the brain, we injected female goldfish with gamma-vinyl GABA (300 microg/g of body weight) (24 h), an irreversible inhibitor of the enzyme GABA transaminase (GABA-T). We found that increased levels of GABA in the hypothalamus resulted in a 2.2-fold down-regulation of GABA(A) receptor beta4 subunit mRNA. In the telencephalon, we found that increased GABA levels resulted in a 1.5-fold increase of CRF mRNA and a 1.8-fold decrease of GABA(A) receptor beta2 subunit mRNA. Increasing GABA in the hypothalamus and telencephalon of the goldfish did not significantly affect the mRNA abundance of genes involved in GABA synthesis (glutamic acid decarboxylase isoforms) and degradation (GABA-T), feeding, or reproduction. Our preliminary study suggests that the regulation of GABA receptor subunit mRNA expression by GABA may be a conserved evolutionary mechanism in vertebrates to modulate GABAergic synaptic transmission.
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Affiliation(s)
- C J Martyniuk
- Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, Canada
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