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Stevenson LM, Muller EB, Nacci D, Clark BW, Whitehead A, Nisbet RM. Connecting Suborganismal Data to Bioenergetic Processes: Killifish Embryos Exposed to a Dioxin-Like Compound. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2023; 42:2040-2053. [PMID: 37232404 DOI: 10.1002/etc.5680] [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: 11/29/2022] [Revised: 01/23/2023] [Accepted: 05/24/2023] [Indexed: 05/27/2023]
Abstract
A core challenge for ecological risk assessment is to integrate molecular responses into a chain of causality to organismal or population-level outcomes. Bioenergetic theory may be a useful approach for integrating suborganismal responses to predict organismal responses that influence population dynamics. We describe a novel application of dynamic energy budget (DEB) theory in the context of a toxicity framework (adverse outcome pathways [AOPs]) to make quantitative predictions of chemical exposures to individuals, starting from suborganismal data. We use early-life stage exposure of Fundulus heteroclitus to dioxin-like chemicals (DLCs) and connect AOP key events to DEB processes through "damage" that is produced at a rate proportional to the internal toxicant concentration. We use transcriptomic data of fish embryos exposed to DLCs to translate molecular indicators of damage into changes in DEB parameters (damage increases somatic maintenance costs) and DEB models to predict sublethal and lethal effects on young fish. By changing a small subset of model parameters, we predict the evolved tolerance to DLCs in some wild F. heteroclitus populations, a data set not used in model parameterization. The differences in model parameters point to reduced sensitivity and altered damage repair dynamics as contributing to this evolved resistance. Our methodology has potential extrapolation to untested chemicals of ecological concern. Environ Toxicol Chem 2023;42:2040-2053. © 2023 Oak Ridge National Laboratory and The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Louise M Stevenson
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California, USA
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio, USA
| | - Erik B Muller
- Marine Science Institute, University of California, Santa Barbara, California, USA
- Institut für Biologische Analytik und Consulting IBACON, Rossdorf, Germany
| | - Diane Nacci
- Atlantic Coastal Environmental Sciences Division, Office of Research and Development, Center for Environmental Measurement and Modeling, US Environmental Protection Agency, Narragansett, Rhode Island
| | - Bryan W Clark
- Atlantic Coastal Environmental Sciences Division, Office of Research and Development, Center for Environmental Measurement and Modeling, US Environmental Protection Agency, Narragansett, Rhode Island
| | - Andrew Whitehead
- Department of Environmental Toxicology, University of California Davis, Davis, California, USA
| | - Roger M Nisbet
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California, USA
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2
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Woo SJ. Molecular characterization of the aryl hydrocarbon receptor 2 gene in black rockfish, Sebastes schlegelii, and its expression patterns upon exposure to benzo[a]pyrene, 2,3,7,8-tetrachlorodibenzo-p-dioxin, and β-naphthoflavone. J Appl Toxicol 2021; 42:638-650. [PMID: 34651326 DOI: 10.1002/jat.4245] [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: 05/29/2021] [Revised: 09/05/2021] [Accepted: 09/13/2021] [Indexed: 11/09/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates the toxicity of halogenated and polycyclic aromatic hydrocarbons in vertebrates. Thus, increased knowledge of AhR-mediated responses to xenobiotics is imperative. Sebastes schlegelii is increasingly being used as a model for studying environmental toxicology; hence, in this study, the presence of AhR2 was evaluated in S. schlegelii. The results showed that the predicted AhR2 amino acid sequence contained regions characteristic of other vertebrate AhRs, including the basic helix-loop-helix and PER-ARNT-SIM domains in the N-terminal half, but it had minor similarity with other vertebrate AhRs across the C-terminal half; it did not contain the distinct glutamine-rich domains found in mammalian AhR2. Phylogenetic analysis demonstrated that S. schlegelii AhR2 was clustered within the teleost AhR2 branch. Additionally, AhR2 mRNA was detectable in all 11 tissues tested, with the highest mRNA levels in the heart, pyloric ceca, and liver. Furthermore, exposure to the AhR agonists showed that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, 1 μg/g body weight) induced a significantly higher increases in AhR2 expression in the gills, liver, kidneys, and spleen in 48 h than benzo[a]pyrene (2 μg/g body weight), and β-naphthoflavone (50-μg/g body weight); AhR2 mRNA levels upon TCDD exposure were up-regulated by 16- and 10-fold in the gills and liver, respectively. These findings indicated that AhR was a highly sensitive receptor against TCDD. Thus, investigating AhR2 expression in the presence of other xenobiotics might offer further information for the elucidation of its crucial role in mediating toxicant metabolism in S. schlegelii.
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Affiliation(s)
- Soo Ji Woo
- Department of Aquatic Life Medicine, Pukyong National University, Busan, South Korea.,Pathology Research Division, National Institute of Fisheries Science, Busan, South Korea
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3
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Segner H, Bailey C, Tafalla C, Bo J. Immunotoxicity of Xenobiotics in Fish: A Role for the Aryl Hydrocarbon Receptor (AhR)? Int J Mol Sci 2021; 22:ijms22179460. [PMID: 34502366 PMCID: PMC8430475 DOI: 10.3390/ijms22179460] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 02/07/2023] Open
Abstract
The impact of anthropogenic contaminants on the immune system of fishes is an issue of growing concern. An important xenobiotic receptor that mediates effects of chemicals, such as halogenated aromatic hydrocarbons (HAHs) and polyaromatic hydrocarbons (PAHs), is the aryl hydrocarbon receptor (AhR). Fish toxicological research has focused on the role of this receptor in xenobiotic biotransformation as well as in causing developmental, cardiac, and reproductive toxicity. However, biomedical research has unraveled an important physiological role of the AhR in the immune system, what suggests that this receptor could be involved in immunotoxic effects of environmental contaminants. The aims of the present review are to critically discuss the available knowledge on (i) the expression and possible function of the AhR in the immune systems of teleost fishes; and (ii) the impact of AhR-activating xenobiotics on the immune systems of fish at the levels of immune gene expression, immune cell proliferation and immune cell function, immune pathology, and resistance to infectious disease. The existing information indicates that the AhR is expressed in the fish immune system, but currently, we have little understanding of its physiological role. Exposure to AhR-activating contaminants results in the modulation of numerous immune structural and functional parameters of fish. Despite the diversity of fish species studied and the experimental conditions investigated, the published findings rather uniformly point to immunosuppressive actions of xenobiotic AhR ligands in fish. These effects are often associated with increased disease susceptibility. The fact that fish populations from HAH- and PAH-contaminated environments suffer immune disturbances and elevated disease susceptibility highlights that the immunotoxic effects of AhR-activating xenobiotics bear environmental relevance.
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Affiliation(s)
- Helmut Segner
- Centre for Fish and Wildlife Health, Department of Pathobiology and Infectious Diseases, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland
| | | | | | - Jun Bo
- Laboratory of Marine Biology and Ecology, Third Institute of Oceanography, Xiamen 361005, China
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4
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Doering JA, Dubiel J, Wiseman S. Predicting Early Life Stage Mortality in Birds and Fishes from Exposure to Low-Potency Agonists of the Aryl Hydrocarbon Receptor: A Cross-Species Quantitative Adverse Outcome Pathway Approach. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2020; 39:2055-2064. [PMID: 32648946 DOI: 10.1002/etc.4816] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/15/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
Dioxin-like compounds (DLCs) cause early life stage mortality of vertebrates through activation of the aryl hydrocarbon receptor (AhR). A prior study developed a cross-species quantitative adverse outcome pathway (qAOP) which can predict full dose-response curves of early life stage mortality for any species of bird or fish exposed to DLCs using the species- and chemical-specific 50% effect concentration (EC50) from an in vitro AhR transactivation assay with COS-7 cells. However, calculating a reliable EC50 for input into this qAOP requires the maximal response of the concentration-response curve to be known, which is not always possible for low-potency agonists, such as some polychlorinated biphenyls (PCBs). To enable predictions for these low-potency agonists, the present study revised this qAOP to use the effect concentration threshold (ECThreshold ) from the in vitro AhR transactivation assay as input. Significant linear relationships were demonstrated between ECThreshold and the dose to cause 0, 10, 50, or 100% mortality among early life stages of 3 species of birds and 7 species of fish for 4 DLCs: 2,3,7,8-tetrachlorodibenzo-p-dioxin, PCB 126, PCB 77, and PCB 105. These 4 linear relationships were combined to form the revised qAOP. This qAOP using the ECThreshold enables prediction of experimental dose-response curves for lower-potency agonists to within an order of magnitude on average, but the prior qAOP using EC50 predicts experimental dose-response curves for higher-potency agonists with greater accuracy. Environ Toxicol Chem 2020;39:2055-2064. © 2020 SETAC.
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Affiliation(s)
- Jon A Doering
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Justin Dubiel
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Steve Wiseman
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada
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5
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Nijoukubo D, Adachi H, Kitazawa T, Teraoka H. Blood vessels are primary targets for 2,3,7,8-tetrachlorodibenzo-p-dioxin in pre-cardiac edema formation in larval zebrafish. CHEMOSPHERE 2020; 254:126808. [PMID: 32339801 DOI: 10.1016/j.chemosphere.2020.126808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/13/2020] [Accepted: 04/13/2020] [Indexed: 05/07/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has adverse effects on the development and function of the heart in zebrafish eleutheroembryos (embryos and larvae). We previously reported that TCDD reduced blood flow in the mesencephalic vein of zebrafish eleutheroembryos long before inducing pericardial edema. In the present study, we compared early edema (pre-cardiac edema), reduction of deduced cardiac output and reduction of blood flow in the dorsal aorta and cardinal vein caused by TCDD. In the same group of eleutheroembryos, TCDD (1.0 ppb) caused pre-cardiac edema and circulation failure at the cardinal vein in the central trunk region with the similar time courses from 42 to 54 h post fertilization (hpf), while the same concentration of TCDD did not significantly affect aortic circulation in the central trunk region or cardiac output. The dependence of pre-cardiac edema on TCDD concentration (0-2.0 ppb) at 55 hpf correlated well with the dependence of blood flow through the cardinal vein on TCDD concentration. Several treatments that markedly inhibited TCDD-induced pre-cardiac edema such as knockdown of aryl hydrocarbon receptor nuclear translocator-1 (ARNT1) and treatment with ascorbic acid, an antioxidant, did not significantly prevent the reduction of cardiac output at 55 hpf caused by 2.0 ppb TCDD. TCDD caused hemorrhage and extravasation of Evans blue that was intravascularly injected with bovine serum albumin, suggesting an increase in endothelium permeability to serum protein induced by TCDD. The results suggest that the blood vessels are primary targets of TCDD in edema formation in larval zebrafish.
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Affiliation(s)
- Daisuke Nijoukubo
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Hikaru Adachi
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Takio Kitazawa
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Hiroki Teraoka
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan.
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6
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Doering JA, Wiseman S, Giesy JP, Hecker M. A Cross-species Quantitative Adverse Outcome Pathway for Activation of the Aryl Hydrocarbon Receptor Leading to Early Life Stage Mortality in Birds and Fishes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:7524-7533. [PMID: 29863850 DOI: 10.1021/acs.est.8b01438] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Dioxin-like compounds (DLCs) elicit adverse effects through activation of the aryl hydrocarbon receptor (AHR). Prior investigations demonstrated that sensitivity to activation of AHR1 in an in vitro AHR transactivation assay is predictive of early life stage mortality among birds. The present study investigated the link between sensitivity to activation of AHR1s and AHR2s and early life stage mortality among fishes. A significant, linear relationship was demonstrated between sensitivity to activation of AHR2 and early life stage mortality among nine fishes, while no relationship was found for AHR1. The slope and y-intercept for the linear relationship between sensitivity to activation of AHR1 and early life stage mortality in birds was not statistically different from the same relationship for AHR2 in fishes. Data for fishes and birds across DLCs were expanded into four significant, linear regression models describing the relationship between sensitivity to activation of AHR and the dose to cause early life stage mortality of 0%, 10%, 50%, or 100%. These four relationships were combined to form a quantitative adverse outcome pathway which can predict dose-response curves of early life stage mortality for DLCs to any bird or fish from species- and chemical-specific responses in an in vitro AHR transactivation assay.
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Affiliation(s)
- Jon A Doering
- Toxicology Centre , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5B3 , Canada
| | - Steve Wiseman
- Toxicology Centre , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5B3 , Canada
- Department of Biological Sciences , University of Lethbridge , Lethbridge , Alberta T1K 3M4 , Canada
| | - John P Giesy
- Toxicology Centre , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5B3 , Canada
- Department of Veterinary Biomedical Sciences , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5B4 , Canada
| | - Markus Hecker
- Toxicology Centre , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5B3 , Canada
- School of Environment and Sustainability , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5C8 , Canada
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7
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Luo JJ, Su DS, Xie SL, Liu Y, Liu P, Yang XJ, Pei DS. Hypersensitive assessment of aryl hydrocarbon receptor transcriptional activity using a novel truncated cyp1a promoter in zebrafish. FASEB J 2018; 32:2814-2826. [PMID: 29298861 DOI: 10.1096/fj.201701171r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent organic pollutant (POP), an unintentional byproduct of various industrial processes, and a human carcinogen. The expression of the cytochrome P450 1A (cyp1a) gene is upregulated in the presence of TCDD through activating the aryl hydrocarbon receptor pathway in a dose-dependent manner. Several essential response elements, including the 8 potential xenobiotic response elements in the cyp1a promoter region, have been identified to be the main functional parts for the response to TCDD. Thus, we aimed to develop a convenient and sensitive biomonitoring tool to examine the level of POPs in the environment and evaluate its potential human health risks by TCDD. Here, we established a transgenic zebrafish model with a red fluorescent reporter gene ( mCherry) using the truncated cyp1a promoter. Under exposure to TCDD, the expression pattern of mCherry in the reporter zebrafish mirrored that of endogenous cyp1a mRNA, and the primary target tissues for TCDD were the brain vessels, liver, gut, cloaca, and skin. Our results indicated that exposure of the embryos to TCDD at concentrations as low as 0.005 nM for 48 h, which did not elicit morphologic abnormalities in the embryos, markedly increased mCherry expression. In addition, the reporter embryos responded to other POPs, and primary liver cell culture of zebrafish revealed that Cyp1a protein was mainly expressed in the cytoplasm of liver cells. Furthermore, our transgenic fish embryos demonstrated that TCDD exposure can regulate the expression levels of several tumor-related factors, including epidermal growth factor, TNF-α, C-myc, proliferating cell nuclear antigen, TGF-β, serine/threonine kinase (Akt), and phosphorylated Akt, suggesting that our transgenic fish can be used as a sensitive model to evaluate the carcinogenicity induced by TCDD exposure.-Luo, J.-J., Su, D.-S., Xie, S.-L., Liu, Y., Liu, P., Yang, X.-J., Pei D.-S. Hypersensitive assessment of aryl hydrocarbon receptor transcriptional activity using a novel truncated cyp1a promoter in zebrafish.
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Affiliation(s)
- Juan-Juan Luo
- Center for Neuroscience, Shantou University Medical College, Shantou, China
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Dong-Sheng Su
- Center for Neuroscience, Shantou University Medical College, Shantou, China
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Shao-Lin Xie
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
- College of Marine Sciences, South China Agricultural University, Guangzhou, China
| | - Yi Liu
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Pei Liu
- Center for Neuroscience, Shantou University Medical College, Shantou, China
| | - Xiao-Jun Yang
- Center for Neuroscience, Shantou University Medical College, Shantou, China
| | - De-Sheng Pei
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
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8
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Mechanisms of 2,3,7,8-tetrachlorodibenzo-p-dioxin- induced cardiovascular toxicity: An overview. Chem Biol Interact 2018; 282:1-6. [PMID: 29317249 DOI: 10.1016/j.cbi.2018.01.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 12/05/2017] [Accepted: 01/05/2018] [Indexed: 11/21/2022]
Abstract
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is an environmental contaminant and its toxicity is mediated by the aryl hydrocarbon receptor (AHR). Mechanisms of TCDD cardiovascular toxicity consist of oxidative stress, growth factor modulation, and ionic current alteration. It is indicated that the rodent cardiovascular system is a target for TCDD cardiomyopathy. Here, our understanding of TCDD cardiovascular toxicity is reviewed.
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9
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Kais B, Schiwy S, Hollert H, Keiter SH, Braunbeck T. In vivo EROD assays with the zebrafish (Danio rerio) as rapid screening tools for the detection of dioxin-like activity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 590-591:269-280. [PMID: 28268020 DOI: 10.1016/j.scitotenv.2017.02.236] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 02/28/2017] [Accepted: 02/28/2017] [Indexed: 06/06/2023]
Abstract
The present study compares two alternative in vivo approaches for the measurement of ethoxyresorufin-O-deethylase (EROD) activity in zebrafish (Danio rerio) following exposure to acetonic model sediment extracts: (1) the live-imaging EROD assay for the direct detection of EROD induction in individual livers via epifluorescence, and (2) the fish embryo EROD assay in subcellular fractions derived from entire zebrafish embryos after in vivo exposure. For toxicity assessment, each sediment extract was tested with the standard fish embryo test (FET). Upon completion of a functioning liver after 72h, the embryos gave a distinct fluorescent signal in the liver, and a corresponding EROD activity could be detected in the fish embryo EROD assay. The exposure time in the live-imaging EROD assay was reduced to 3h, which resulted in a stronger, less variable and more sensitive EROD response. Overall, the live-imaging and the fish embryo EROD assays showed the same tendencies and gave comparable results, e.g. a concentration-dependent increase in EROD activity at concentrations one order of magnitude below concentrations producing macroscopically visible abnormalities. At higher concentrations, however, a decrease of EROD activity was observed in either test. Both tests ranked the three model sediment extracts in the same order. Results indicate that both test systems complement each other and together provide a rapid and reliable in vivo tool to investigate the presence of dioxin-like substances in environmental samples.
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Affiliation(s)
- Britta Kais
- Aquatic Ecology and Toxicology Group, Center for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 120, D-69120 Heidelberg, Germany.
| | - Sabrina Schiwy
- Department of Ecosystem Analysis, Institute for Environmental Research, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Henner Hollert
- Department of Ecosystem Analysis, Institute for Environmental Research, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Steffen H Keiter
- Department of Ecosystem Analysis, Institute for Environmental Research, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Thomas Braunbeck
- Aquatic Ecology and Toxicology Group, Center for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 120, D-69120 Heidelberg, Germany
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10
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Abstract
As manufacturing processes and development of new synthetic compounds increase to keep pace with the expanding global demand, environmental health, and the effects of toxicant exposure are emerging as critical public health concerns. Additionally, chemicals that naturally occur in the environment, such as metals, have profound effects on human and animal health. Many of these compounds are in the news: lead, arsenic, and endocrine disruptors such as bisphenol A have all been widely publicized as causing disease or damage to humans and wildlife in recent years. Despite the widespread appreciation that environmental toxins can be harmful, there is limited understanding of how many toxins cause disease. Zebrafish are at the forefront of toxicology research; this system has been widely used as a tool to detect toxins in water samples and to investigate the mechanisms of action of environmental toxins and their related diseases. The benefits of zebrafish for studying vertebrate development are equally useful for studying teratogens. Here, we review how zebrafish are being used both to detect the presence of some toxins as well as to identify how environmental exposures affect human health and disease. We focus on areas where zebrafish have been most effectively used in ecotoxicology and in environmental health, including investigation of exposures to endocrine disruptors, industrial waste byproducts, and arsenic.
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Affiliation(s)
- Kathryn Bambino
- Icahn School of Medicine at Mount Sinai, New York, United States
| | - Jaime Chu
- Icahn School of Medicine at Mount Sinai, New York, United States.
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Gostomska-Pampuch K, Ostrowska A, Kuropka P, Dobrzyński M, Ziółkowski P, Kowalczyk A, Łukaszewicz E, Gamian A, Całkosiński I. Protective effects of levamisole, acetylsalicylic acid, and α-tocopherol against dioxin toxicity measured as the expression of AhR and COX-2 in a chicken embryo model. Histochem Cell Biol 2016; 147:523-536. [PMID: 27942866 PMCID: PMC5359382 DOI: 10.1007/s00418-016-1528-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/29/2016] [Indexed: 11/28/2022]
Abstract
Polychlorinated dibenzo-p-dioxins and dibenzofurans (dioxins) are classed as persistent organic pollutants and have adverse effects on multiple functions within the body. Dioxins are known carcinogens, immunotoxins, and teratogens. Dioxins are transformed in vivo, and interactions between the products and the aryl hydrocarbon receptor (AhR) lead to the formation of proinflammatory and toxic metabolites. The aim of this study was to determine whether α-tocopherol (vitamin E), acetylsalicylic acid (ASA), and levamisole can decrease the amount of damage caused by dioxins. Fertile Hubbard Flex commercial line chicken eggs were injected with solutions containing 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or containing TCDD and the test compounds. The chicken embryos and organs were analyzed after 7 and 13 days. The levels at which AhR and cyclooxygenase-2 (COX-2) proteins (which are induced during inflammation) were expressed were evaluated by performing immunohistochemical analyses on embryos treated with TCDD alone or with TCDD and the test compounds. TCDD caused developmental disorders and increased AhR and COX-2 expression in the chicken embryo tissues. Vitamin E, levamisole, ASA, and ASA plus vitamin E inhibited AhR and COX-2 expression in embryos after 7 days and decreased AhR and COX-2 expression in embryos after 13 days. ASA, levamisole, and ASA plus vitamin E weakened the immune response and prevented multiple organ changes. Vitamin E was not fully protective against developmental changes in the embryos.
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Affiliation(s)
- Kinga Gostomska-Pampuch
- Department of Immunology of Infectious Diseases, Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wrocław, Poland.
| | - Alicja Ostrowska
- Laboratory of Neurotoxicology and Environmental Diagnostics, Wroclaw Medical University, Bartla 5, 51-618, Wrocław, Poland
| | - Piotr Kuropka
- Department of Animal Physiology and Biostructure, Wroclaw University of Environmental and Life Sciences, Norwida 31, 50-375, Wrocław, Poland
| | - Maciej Dobrzyński
- Department of Conservative Dentistry and Pedodontics, Wroclaw Medical University, Krakowska 26, 50-425, Wrocław, Poland
| | - Piotr Ziółkowski
- Department of Pathomorphology, Wroclaw Medical University, Marcinkowskiego 1, 50-368, Wrocław, Poland
| | - Artur Kowalczyk
- Institute of Animal Breeding, Wroclaw University of Environmental and Life Sciences, Chełmońskiego 38c, 51-630, Wrocław, Poland
| | - Ewa Łukaszewicz
- Institute of Animal Breeding, Wroclaw University of Environmental and Life Sciences, Chełmońskiego 38c, 51-630, Wrocław, Poland
| | - Andrzej Gamian
- Department of Immunology of Infectious Diseases, Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wrocław, Poland.,Department of Medical Biochemistry, Wroclaw Medical University, Chałubińskiego 10, 50-368, Wrocław, Poland.,Wroclaw Research Centre EIT+, Wrocław, Poland
| | - Ireneusz Całkosiński
- Laboratory of Neurotoxicology and Environmental Diagnostics, Wroclaw Medical University, Bartla 5, 51-618, Wrocław, Poland
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12
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Nijoukubo D, Tanaka Y, Okuno Y, Yin G, Kitazawa T, Peterson RE, Kubota A, Teraoka H. Protective effect of prostacyclin against pre-cardiac edema caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin and a thromboxane receptor agonist in developing zebrafish. CHEMOSPHERE 2016; 156:111-117. [PMID: 27174823 DOI: 10.1016/j.chemosphere.2016.04.107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 04/22/2016] [Accepted: 04/25/2016] [Indexed: 06/05/2023]
Abstract
The role of prostaglandin pathways has been suggested in some toxicological responses to dioxins. Cyclooxygenase type 2b (COX2b), thromboxane synthase, and the thromboxane receptor (TP) pathway have been implicated in mediating 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced pre-cardiac edema in developing zebrafish at 55 h post fertilization (hpf). Pre-cardiac edema refers to edema located in a small cavity between the heart and body wall of zebrafish eleutheroembryos. In the present study, we assessed the role of prostacyclin, which counteracts some biological effects of thromboxane, in TCDD-induced pre-cardiac edema. Pre-cardiac edema induced by TCDD exposure (0.5 and 1 ppb) beginning at 24 hpf was markedly inhibited by exposure to beraprost (5 and 10 μM), a prostacyclin receptor (IP) agonist, beginning at 33 hpf. The preventive effect of beraprost was reduced by exposure to CAY10441 (10 μM), an IP antagonist starting at 33 hpf. Knockdowns of the IP receptor (IP-KD) with two different morpholinos caused edema by themselves and enhanced pre-cardiac edema caused by the low concentration of TCDD (0.5 ppb). On the other hand, short exposure beginning at 48 hpf to U46619 (7.5-30 μM), a thromboxane receptor agonist caused pre-cardiac edema, which was inhibited by exposure beginning at 48 hpf to both ICI-192,605 (24 μM), a TP antagonist, and beraprost. Expression of prostacyclin synthase was increased from fertilization, plateaued by 48 hpf, and was maintained until at least 96 hpf. Overall, the results demonstrate a preventive effect of prostacyclin on TCDD-induced pre-cardiac edema in developing zebrafish.
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Affiliation(s)
- Daisuke Nijoukubo
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Yasuaki Tanaka
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Yuki Okuno
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Guojun Yin
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan; Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China
| | - Takio Kitazawa
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | | | - Akira Kubota
- Diagnostic Center for Animal Health and Food Safety, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | - Hiroki Teraoka
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan.
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Sarihan ME, Parlakpinar H, Ciftci O, Yilmaz F, Sagir M, Yilmaz O, Ceker G. Protective effects of melatonin against 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced cardiac injury in rats. Eur J Pharmacol 2015; 762:214-20. [DOI: 10.1016/j.ejphar.2015.04.054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 04/28/2015] [Accepted: 04/30/2015] [Indexed: 11/30/2022]
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The transcriptional response to oxidative stress during vertebrate development: effects of tert-butylhydroquinone and 2,3,7,8-tetrachlorodibenzo-p-dioxin. PLoS One 2014; 9:e113158. [PMID: 25402455 PMCID: PMC4234671 DOI: 10.1371/journal.pone.0113158] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 10/20/2014] [Indexed: 01/12/2023] Open
Abstract
Oxidative stress is an important mechanism of chemical toxicity, contributing to teratogenesis and to cardiovascular and neurodegenerative diseases. Developing animals may be especially sensitive to chemicals causing oxidative stress. The developmental expression and inducibility of anti-oxidant defenses through activation of NF-E2-related factor 2 (NRF2) affect susceptibility to oxidants, but the embryonic response to oxidants is not well understood. To assess the response to chemically mediated oxidative stress and how it may vary during development, zebrafish embryos, eleutheroembryos, or larvae at 1, 2, 3, 4, 5, and 6 days post fertilization (dpf) were exposed to DMSO (0.1%), tert-butylhydroquinone (tBHQ; 10 µM) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 2 nM) for 6 hr. Transcript abundance was assessed by real-time qRT-PCR and microarray. qRT-PCR showed strong (4- to 5-fold) induction of gstp1 by tBHQ as early as 1 dpf. tBHQ also induced gclc (2 dpf), but not sod1, nqo1, or cyp1a. TCDD induced cyp1a but none of the other genes. Microarray analysis showed that 1477 probes were significantly different among the DMSO-, tBHQ-, and TCDD-treated eleutheroembryos at 4 dpf. There was substantial overlap between genes induced in developing zebrafish and a set of marker genes induced by oxidative stress in mammals. Genes induced by tBHQ in 4-dpf zebrafish included those involved in glutathione synthesis and utilization, signal transduction, and DNA damage/stress response. The strong induction of hsp70 determined by microarray was confirmed by qRT-PCR and by use of transgenic zebrafish expressing enhanced green fluorescent protein (EGFP) under control of the hsp70 promoter. Genes strongly down-regulated by tBHQ included mitfa, providing a molecular explanation for the loss of pigmentation in tBHQ-exposed embryos. These data show that zebrafish embryos are responsive to oxidative stress as early as 1 dpf, that responsiveness varies with development in a gene-specific manner, and that the oxidative stress response is substantially conserved in vertebrate animals.
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Teraoka H, Okuno Y, Nijoukubo D, Yamakoshi A, Peterson RE, Stegeman JJ, Kitazawa T, Hiraga T, Kubota A. Involvement of COX2-thromboxane pathway in TCDD-induced precardiac edema in developing zebrafish. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 154:19-26. [PMID: 24858302 PMCID: PMC4326229 DOI: 10.1016/j.aquatox.2014.04.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 04/19/2014] [Accepted: 04/21/2014] [Indexed: 05/06/2023]
Abstract
The cardiovascular system is one of the most characteristic and important targets for developmental toxicity by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in fish larvae. However, knowledge of the mechanism of TCDD-induced edema after heterodimerization of aryl hydrocarbon receptor type 2 (AHR2) and AHR nuclear translocator type 1 (ARNT1) is still limited. In the present study, microscopic analysis with a high-speed camera revealed that TCDD increased the size of a small cavity between the heart and body wall in early eleutheroembryos, a toxic effect that we designate as precardiac edema. A concentration-response curve for precardiac edema at 2 days post fertilization (dpf) showed close similarity to that for conventional pericardial edema at 3 dpf. Precardiac edema caused by TCDD was reduced by morpholino knockdown of AHR2 and ARNT1, as well as by an antioxidant (ascorbic acid). A selective inhibitor of cyclooxygenase type 2 (COX2), NS398, also markedly inhibited TCDD-induced precardiac edema. A thromboxane receptor (TP) antagonist, ICI-192,605 almost abolished TCDD-induced precardiac edema and this effect was canceled by U46619, a TP agonist, which was not influential in the action of TCDD by itself. Knockdown of COX2b and thromboxane A synthase 1 (TBXS), but not COX2a, strongly reduced TCDD-induced precardiac edema. Knockdown of COX2b was without effect on mesencephalic circulation failure caused by TCDD. The edema by TCDD was also inhibited by knockdown of c-mpl, a thrombopoietin receptor necessary for thromobocyte production. Finally, induction of COX2b, but not COX2a, by TCDD was seen in eleutheroembryos at 3 dpf. These results suggest a role of the COX2b-thromboxane pathway in precardiac edema formation following TCDD exposure in developing zebrafish.
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Affiliation(s)
- Hiroki Teraoka
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan.
| | - Yuki Okuno
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Daisuke Nijoukubo
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Ayumi Yamakoshi
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | | | - John J Stegeman
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Takio Kitazawa
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Takeo Hiraga
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Akira Kubota
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan; Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
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Reitzel AM, Karchner SI, Franks DG, Evans BR, Nacci D, Champlin D, Vieira VM, Hahn ME. Genetic variation at aryl hydrocarbon receptor (AHR) loci in populations of Atlantic killifish (Fundulus heteroclitus) inhabiting polluted and reference habitats. BMC Evol Biol 2014; 14:6. [PMID: 24422594 PMCID: PMC3899389 DOI: 10.1186/1471-2148-14-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 12/18/2013] [Indexed: 11/27/2022] Open
Abstract
Background The non-migratory killifish Fundulus heteroclitus inhabits clean and polluted environments interspersed throughout its range along the Atlantic coast of North America. Several populations of this species have successfully adapted to environments contaminated with toxic aromatic hydrocarbon pollutants such as polychlorinated biphenyls (PCBs). Previous studies suggest that the mechanism of resistance to these and other “dioxin-like compounds” (DLCs) may involve reduced signaling through the aryl hydrocarbon receptor (AHR) pathway. Here we investigated gene diversity and evidence for positive selection at three AHR-related loci (AHR1, AHR2, AHRR) in F. heteroclitus by comparing alleles from seven locations ranging over 600 km along the northeastern US, including extremely polluted and reference estuaries, with a focus on New Bedford Harbor (MA, USA), a PCB Superfund site, and nearby reference sites. Results We identified 98 single nucleotide polymorphisms within three AHR-related loci among all populations, including synonymous and nonsynonymous substitutions. Haplotype distributions were spatially segregated and F-statistics suggested strong population genetic structure at these loci, consistent with previous studies showing strong population genetic structure at other F. heteroclitus loci. Genetic diversity at these three loci was not significantly different in contaminated sites as compared to reference sites. However, for AHR2 the New Bedford Harbor population had significant FST values in comparison to the nearest reference populations. Tests for positive selection revealed ten nonsynonymous polymorphisms in AHR1 and four in AHR2. Four nonsynonymous SNPs in AHR1 and three in AHR2 showed large differences in base frequency between New Bedford Harbor and its reference site. Tests for isolation-by-distance revealed evidence for non-neutral change at the AHR2 locus. Conclusion Together, these data suggest that F. heteroclitus populations in reference and polluted sites have similar genetic diversity, providing no evidence for strong genetic bottlenecks for populations in polluted locations. However, the data provide evidence for genetic differentiation among sites, selection at specific nucleotides in AHR1 and AHR2, and specific AHR2 SNPs and haplotypes that are associated with the PCB-resistant phenotype in the New Bedford Harbor population. The results suggest that AHRs, and especially AHR2, may be important, recurring targets for selection in local adaptation to dioxin-like aromatic hydrocarbon contaminants.
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Affiliation(s)
| | | | | | | | | | | | | | - Mark E Hahn
- Biology Department, Woods Hole Oceanographic Institution, 45 Water Street, Woods Hole, MA 02568, USA.
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Kim KH, Park HJ, Kim JH, Kim S, Williams DR, Kim MK, Jung YD, Teraoka H, Park HC, Choy HE, Shin BA, Choi SY. Cyp1a reporter zebrafish reveals target tissues for dioxin. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2013; 134-135:57-65. [PMID: 23587668 DOI: 10.1016/j.aquatox.2013.03.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 02/25/2013] [Accepted: 03/04/2013] [Indexed: 06/02/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is the unintentional byproduct of various industrial processes, is classified as human carcinogen and could disrupt reproductive, developmental and endocrine systems. Induction of cyp1a1 is used as an indicator of TCDD exposure. We sought to determine tissues that are vulnerable to TCDD toxicity using a transgenic zebrafish (Danio rerio) model. We inserted a nuclear enhanced green fluorescent protein gene (EGFP) into the start codon of a zebrafish cyp1a gene in a fosmid clone using DNA recombineering. The resulting recombineered fosmid was then used to generate cyp1a reporter zebrafish, embryos of which were exposed to TCDD. Expression pattern of EGFP in the reporter zebrafish mirrored that of endogenous cyp1a mRNA. In addition, exposure of the embryos to TCDD at as low as 10 pM for 72 h, which does not elicit morphological abnormalities of embryos, markedly increased GFP expression. Furthermore, the reporter embryos responded to other AhR ligands as well. Exposure of the embryos to TCDD revealed previously reported (the cardiovascular system, liver, pancreas, kidney, swim bladder and skin) and unreported target tissues (retinal bipolar cells, otic vesicle, lateral line, cloaca and pectoral fin bud) for TCDD. Transgenic cyp1a reporter zebrafish we have developed can further understanding of ecotoxicological relevance and human health risks by TCDD. In addition, they could be used to identify agonists of AhR and antidotes to TCDD toxicity.
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Affiliation(s)
- Kun-Hee Kim
- Department of Biomedical Sciences, Chonnam National University Medical School, Gwangju, Republic of Korea
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Iida M, Kim EY, Murakami Y, Shima Y, Iwata H. Toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the peripheral nervous system of developing red seabream (Pagrus major). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2013; 128-129:193-202. [PMID: 23314332 DOI: 10.1016/j.aquatox.2012.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 12/07/2012] [Accepted: 12/11/2012] [Indexed: 06/01/2023]
Abstract
We investigated 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced effects on the morphology of peripheral nervous system (PNS) in the developing red seabream (Pagrus major) embryos. The embryos at 10h post-fertilization (hpf) were treated with 0, 0.1, 0.4 or 1.7 μg/L of TCDD in seawater for 80 min. The morphology of PNS was microscopically observed with florescence staining using an anti-acetylated tubulin antibody at 48, 78, 120 and 136 hpf. Axon length of facial nerve (VII) was found to be shortened by TCDD exposure. Axon guidance in the glossopharyngeal nerve (IX) and vagus nerve (X) was altered at 120 and 136 hpf in a TCDD dose-dependent manner. Lowest observable effect level of TCDD (0.1 μg/L) that induced the morphological alteration of PNS was lower than those of other endpoints on morphological deformities so far reported. Given that the growth cone at the tip of growing nerve axons advances under the influence of its surrounding tissues, we hypothesized that TCDD exposure would affect (1) the nerve cell proliferation/differentiation, (2) the structure of muscle as an axon target and (3) the nerve guidance factor in the embryos. By the immunostaining of embryos with an antibody against the neuronal specific RNA-binding protein, HuD, and an antibody against the sarcomeric myosin, no morphological effects were observed on the neural proliferation/differentiation and the structure of facial muscles of TCDD-treated embryos. In contrast, whole mount in situ hybridization of semaphorin 3A (Sema3A), a secretory axon repulsion factor, revealed the altered expression pattern of its transcripts in TCDD-treated embryos. Our findings suggest that TCDD treatment affects the projection of PNS in the developing red seabream embryos through the effects on the axonal growth cone guidance molecule such as Sema3A, but not on the neuronal differentiation/proliferation and axon target. The PNS in developing embryos may be one of the most sensitive biomarkers to the exposure of dioxin-like compounds.
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Affiliation(s)
- Midori Iida
- Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama, Japan
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19
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Yuan X, Liu L, Pu Y, Zhang X, He X, Fu Y. 2,3,7,8-Tetrachlorodibenzo-p-dioxin induces a proteomic pattern that defines cleft palate formation in mice. Food Chem Toxicol 2012; 50:2270-4. [DOI: 10.1016/j.fct.2012.04.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 04/17/2012] [Accepted: 04/19/2012] [Indexed: 11/15/2022]
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Ko SK, Shin I. Cardiosulfa induces heart deformation in zebrafish through the AhR-mediated, CYP1A-independent pathway. Chembiochem 2012; 13:1483-9. [PMID: 22692990 DOI: 10.1002/cbic.201200177] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Indexed: 11/07/2022]
Abstract
Heart development is a complicated and elaborate biological process. To study this and similar complicated process and diseases, the discovery and use of small molecules for probing biological events is invaluable. As part of such an investigation, we have identified cardiosulfa, a small molecule that induces severely impaired heart morphology and function in zebrafish. The results of the present study show that cardiosulfa-promoted heart deformation is protected by negative regulators of the aryl hydrocarbon receptor (AhR) signaling pathway, such as the AhR antagonist CH-223191 and an AhR2-morpholino antisense oligonucleotide, zfahr2-MO. However, the toxic effect of cardiosulfa is not alleviated by zfcyp1a-MO, a morpholino antisense oligo for cytochrome P450 1A (CYP1A), which is the most well-characterized gene of the AhR pathway. Similar results were obtained for the known AhR agonist PCB126. These observations suggest that cardiosulfa causes heart deformation in zebrafish through the AhR-mediated, CYP1A-independent pathway. Our results indicate that cardiosulfa has potential as a novel type of a biological probe to investigate the AhR pathway.
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Affiliation(s)
- Sung-Kyun Ko
- Center for Biofunctional Molecules, Department of Chemistry, Yonsei University, 120-749 Seoul, Korea
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21
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Goldstone HMH, Tokunaga S, Schlezinger JJ, Goldstone JV, Stegeman JJ. EZR1: a novel family of highly expressed retroelements induced by TCDD and regulated by a NF-κB-like factor in embryos of zebrafish (Danio rerio). Zebrafish 2012; 9:15-25. [PMID: 22356696 DOI: 10.1089/zeb.2011.0722] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Transcript profiling using a zebrafish heart cDNA library previously revealed abundant expressed sequence tags (ESTs) upregulated in zebrafish embryos treated with the aryl hydrocarbon receptor (AHR) agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Here, we identify those ESTs as LTR-containing retroelements termed EZR1 (Expressed-Zebrafish-Retroelement group 1). EZR1 is highly redundant in the genome and includes canonical long terminal repeats (LTRs) flanking an integrase-like open reading frame and a region similar to retroviral envelope protein genes. EZR1 sequences lack reverse transcriptase, RNase H, or protease, indicating retrotransposition would be nonautonomous. No AHR binding motifs were found in the EZR1 promoter region. A putative NF-κB-binding site was found, and TCDD-treated zebrafish embryos had significantly increased levels of nuclear protein(s) binding to this sequence. Protein-EZR1 DNA complex formation was partially competed by a mammalian consensus κB sequence, consistent with NF-κB-like activation contributing to increased protein binding to this site. Mobility of the TCDD-induced protein-EZR1 complex differed from that of authentic NF-κB protein bound to the consensus κB site. The results suggest that EZR1 is regulated by interaction with NF-κB or NF-κB-like protein(s) different from the NF-κB protein binding to the consensus κB site. The nature of the NF-κB-like protein and the relationship between EZR1 induction and cardiovascular toxicity caused by TCDD warrant further investigation.
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Affiliation(s)
- Heather M H Goldstone
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
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22
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Marit JS, Weber LP. Persistent effects on adult swim performance and energetics in zebrafish developmentally exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 106-107:131-139. [PMID: 22155425 DOI: 10.1016/j.aquatox.2011.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 10/29/2011] [Accepted: 11/03/2011] [Indexed: 05/31/2023]
Abstract
TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) remains a potent and persistent toxicant in aquatic environments, causing lethal developmental deformities in fish. However, few studies have examined sublethal or persistent effects of developmental TCDD exposure and none have examined its effects on swimming capabilities in sub-adult fish. The objective of the current study was to examine whether effects of TCDD exposure during the critical period of cardiovascular development (2-4 days post fertilization) on swim performance, triglyceride stores and cardiovascular deformities would persist until adulthood in zebrafish. Zebrafish larvae were exposed between 48 and 96 h post fertilization to 1, 0.1, 0.01 ng/L TCDD or DMSO control (0.005%), then raised in clean water for 90 days. Despite having equal survivability, no significant increase in gross deformities and no change in cytochrome P450 1A (CYP1A) activity was observed, while critical swimming speed and dorsal aorta diameter were significantly decreased in TCDD-exposed fish at 90 days. Furthermore, whole body triglycerides were significantly elevated in TCDD-exposed fish both before and after swim testing. Therefore sublethal TCDD exposure during zebrafish development caused a persistent decrease in swim endurance. The cause of this persistent decrease in swim endurance is not known, but may be related to behavioral adaptations limiting swimming capabilities, failure to mobilize triglyceride stores, vascular deformities limiting blood flow to the periphery, or a combination of these factors.
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Affiliation(s)
- Jordan S Marit
- Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4
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Wang J, Liu X, Li T, Liu C, Zhao Y. Increased hepatic Igf2 gene expression involves C/EBPβ in TCDD-induced teratogenesis in rats. Reprod Toxicol 2011; 32:313-21. [DOI: 10.1016/j.reprotox.2011.06.117] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Revised: 05/24/2011] [Accepted: 06/14/2011] [Indexed: 10/18/2022]
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Neri T, Merico V, Fiordaliso F, Salio M, Rebuzzini P, Sacchi L, Bellazzi R, Redi CA, Zuccotti M, Garagna S. The differentiation of cardiomyocytes from mouse embryonic stem cells is altered by dioxin. Toxicol Lett 2011; 202:226-36. [PMID: 21354282 DOI: 10.1016/j.toxlet.2011.02.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 02/10/2011] [Accepted: 02/11/2011] [Indexed: 12/15/2022]
Abstract
2,3,7,8-Tetrachlorodibenzo-para-dioxin (TCDD) causes abnormalities during heart development. Cardiomyocytes derived from embryonic stem (ES) cells are a robust model for the study of early cardiomyogenesis. Here, we evaluated the effects of TCDD at key stages during the differentiation of mouse ES cells into cardiomyocytes analysing: (i) the transcription of lineage differentiation (Brachyury, Nkx-2.5, Actc-1), cardiac-specific (Alpk3, cTnT, cTnI, cTnC) and detoxification phase I (Cyp1A1, Cyp1A2 and Cyp1B1) and phase II (Nqo1, Gsta1 and Ugt1a6) genes; (ii) the global gene expression; (iii) the ultrastructure of ES-derived cardiomyocytes; (iv) level of ATP production and (v) the immunolocalisation of sarcomeric α-actinin, β-myosin heavy chain and cTnT proteins. We show that TCDD affects the differentiation of ES cells into cardiomyocytes at several levels: (1) induces the expression of phase I genes; (2) down-regulates a group of heart-specific genes, some involved in the oxidative phosphorylation pathway; (3) reduces the efficiency of differentiation; (4) alters the arrangement of mitochondria, that show twisted and disrupted cristae, and of some sarcomeres, with misalignement or disarrangement of the myofibrillar organisation and (5) reduces ATP production. This study provides novel evidences that TCDD impairs cardiomyocyte differentiation. Sarcomeres and mitochondria could be a target for dioxin toxicity, their disruption representing a possible mechanism developing cardiac injury.
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Affiliation(s)
- Tui Neri
- Laboratorio di Biologia dello Sviluppo, Dipartimento di Biologia Animale, Universita' degli Studi di Pavia, Via Ferrata 9, 27100 Pavia, Italy
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25
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Teraoka H, Ogawa A, Kubota A, Stegeman JJ, Peterson RE, Hiraga T. Malformation of certain brain blood vessels caused by TCDD activation of Ahr2/Arnt1 signaling in developing zebrafish. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 99:241-7. [PMID: 20554057 PMCID: PMC3040289 DOI: 10.1016/j.aquatox.2010.05.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 04/20/2010] [Accepted: 05/04/2010] [Indexed: 05/07/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) causes various signs of toxicity in early life stages of vertebrates through activation of the aryl hydrocarbon receptor (AHR). The AHR also plays important roles in normal development in mice, and AHR(-/-) mice show abnormal development of vascular structures in various blood vessels. Our previous studies revealed that Ahr type 2 (Ahr2) activation by TCDD and beta-naphthoflavone (BNF) caused a significant decrease in blood flow in the dorsal midbrain of zebrafish embryos. Here we report effects of TCDD exposure on the morphology of some blood vessels in the head of developing zebrafish. TCDD caused concentration-dependent anatomical rearrangements in the shape of the prosencephalic artery in zebrafish larvae. In contrast, no major vascular defects were recognized in the trunk and tail regions following exposure to TCDD at least at the concentrations used. Essentially, the same observations were also confirmed in BNF-exposed larvae. Knock-down of either Ahr2 or Ahr nuclear translocator type 1 (Arnt1) by morpholino oligonucleotides (MOs) protected larvae against abnormal shape of the prosencephalic artery caused by TCDD and BNF. On the other hand, knock-down of Ahr2 or Arnt1 in vehicle-exposed zebrafish larvae had no clear effect on morphology of the prosencephalic artery or trunk vessels. Ascorbic acid, an antioxidant, protected against the TCDD-induced decrease in blood flow through the prosencephalic artery, but not the abnormal morphological changes in the shape of this artery. These results indicate that activation of Ahr2/Arnt1 pathway by TCDD and BNF affects the shape of certain blood vessels in the brain of developing zebrafish.
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Affiliation(s)
- Hiroki Teraoka
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu 069-8501, Japan.
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Alexeyenko A, Wassenberg DM, Lobenhofer EK, Yen J, Linney E, Sonnhammer ELL, Meyer JN. Dynamic zebrafish interactome reveals transcriptional mechanisms of dioxin toxicity. PLoS One 2010; 5:e10465. [PMID: 20463971 PMCID: PMC2864754 DOI: 10.1371/journal.pone.0010465] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 03/17/2010] [Indexed: 01/09/2023] Open
Abstract
Background In order to generate hypotheses regarding the mechanisms by which 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin) causes toxicity, we analyzed global gene expression changes in developing zebrafish embryos exposed to this potent toxicant in the context of a dynamic gene network. For this purpose, we also computationally inferred a zebrafish (Danio rerio) interactome based on orthologs and interaction data from other eukaryotes. Methodology/Principal Findings Using novel computational tools to analyze this interactome, we distinguished between dioxin-dependent and dioxin-independent interactions between proteins, and tracked the temporal propagation of dioxin-dependent transcriptional changes from a few genes that were altered initially, to large groups of biologically coherent genes at later times. The most notable processes altered at later developmental stages were calcium and iron metabolism, embryonic morphogenesis including neuronal and retinal development, a variety of mitochondria-related functions, and generalized stress response (not including induction of antioxidant genes). Within the interactome, many of these responses were connected to cytochrome P4501A (cyp1a) as well as other genes that were dioxin-regulated one day after exposure. This suggests that cyp1a may play a key role initiating the toxic dysregulation of those processes, rather than serving simply as a passive marker of dioxin exposure, as suggested by earlier research. Conclusions/Significance Thus, a powerful microarray experiment coupled with a flexible interactome and multi-pronged interactome tools (which are now made publicly available for microarray analysis and related work) suggest the hypothesis that dioxin, best known in fish as a potent cardioteratogen, has many other targets. Many of these types of toxicity have been observed in mammalian species and are potentially caused by alterations to cyp1a.
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Affiliation(s)
- Andrey Alexeyenko
- Stockholm Bioinformatics Centre, Stockholm University, Stockholm, Sweden
| | - Deena M. Wassenberg
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | | | - Jerry Yen
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Elwood Linney
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | | | - Joel N. Meyer
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
- * E-mail:
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Arzuaga X, Elskus A. Polluted-site killifish (Fundulus heteroclitus) embryos are resistant to organic pollutant-mediated induction of CYP1A activity, reactive oxygen species, and heart deformities. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2010; 29:676-682. [PMID: 20821494 DOI: 10.1002/etc.68] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Exposure to coplanar polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) can adversely affect fish embryonic development, induce expression of cytochrome P4501A (CYP1A), and increase reactive oxygen species (ROS) production, effects believed to be mediated by the aryl hydrocarbon receptor (AHR). Killifish (Fundulus heteroclitus) populations in New Bedford Harbor, Massachusetts, USA (NBH) and Newark Bay, New Jersey, USA (NB) are generationally exposed to coplanar PCBs and PAHs and have developed resistance to PCB mediated induction of CYP1A. We hypothesized that fish resistant to CYP1A induction would also exhibit resistance to PCB and PAH induced ROS production and teratogenesis. Killifish embryos from two contaminated (NB, NBH) and two reference-site populations were exposed to vehicle or 3,3'4,4'5-pentachlorobiphenyl (PCB126) or 3-methylcholanthrene (3-MC) and evaluated for in ovo CYP1A activity, heart deformities, and ROS production. Both chemicals significantly increased in ovo ethoxyresorufin-O-deethylase (EROD) and ROS production in reference-site embryos. These chemicals provoked only moderate induction of in ovo EROD in NBH and NB embryos, and neither PCB126 nor 3-MC induced ROS production in these populations. Similarly, heart deformities were significantly induced by PCB126 in reference-site embryos, but had no significant effects on NB and NBH animals. These results indicate that fish resistant to CYP1A induction also exhibit decreased sensitivity to PCB126 and 3-MC-induced ROS production and teratogenesis. These findings further our understanding of toxicant resistance by demonstrating that reduced response to coplanar PCBs and PAHs extends beyond resistance to CYP1A induction to resistance to the physiological and teratogenic effects of these toxicants, responses that undoubtedly contribute to the increased survival of killifish inhabiting contaminated sites.
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Affiliation(s)
- Xabier Arzuaga
- Graduate Center for Toxicology, 306 Health Sciences Research Bulding, Lexington, Kentucky 40536-0305, USA.
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Brannen KC, Panzica-Kelly JM, Danberry TL, Augustine-Rauch KA. Development of a zebrafish embryo teratogenicity assay and quantitative prediction model. ACTA ACUST UNITED AC 2010; 89:66-77. [DOI: 10.1002/bdrb.20223] [Citation(s) in RCA: 208] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Stegeman JJ, Goldstone JV, Hahn ME. Perspectives on zebrafish as a model in environmental toxicology. FISH PHYSIOLOGY 2010. [DOI: 10.1016/s1546-5098(10)02910-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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30
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Ko SK, Jin H, Jung DW, Tian X, Shin I. Cardiosulfa, a Small Molecule that Induces Abnormal Heart Development in Zebrafish, and Its Biological Implications. Angew Chem Int Ed Engl 2009; 48:7809-12. [DOI: 10.1002/anie.200902370] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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31
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Ko SK, Jin H, Jung DW, Tian X, Shin I. Cardiosulfa, a Small Molecule that Induces Abnormal Heart Development in Zebrafish, and Its Biological Implications. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200902370] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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32
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Jones SP, Kennedy SW. Chicken embryo cardiomyocyte cultures--a new approach for studying effects of halogenated aromatic hydrocarbons in the avian heart. Toxicol Sci 2009; 109:66-74. [PMID: 19223662 DOI: 10.1093/toxsci/kfp039] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), polychlorinated biphenyls (PCBs), and other halogenated aromatic hydrocarbons (HAHs) elicit a variety of adverse biological effects on the cardiovascular systems of mammalian, piscine and avian species. Many of the cardiotoxic effects of HAHs are mediated by the aryl hydrocarbon receptor (AHR). Induction of cytochrome P4501A (CYP1A) is a well-known AHR-dependent response to HAHs in the liver, but there are a limited number of studies on CYP1A induction by these compounds in the heart. We used an in vitro approach to examine effects of TCDD and 3,3',4,4'-tetrachlorobiphenyl (PCB 77) on CYP1A in the avian heart. The responses of primary cultures of chicken embryo cardiomyocytes (CEC) and chicken embryo hepatocytes (CEH) to TCDD and PCB 77 were compared using immunofluorescence staining for CYP1A, the ethoxyresorufin-O-deethylase (EROD) assay, and real-time RT-PCR analysis of CYP1A4 mRNA and CYP1A5 mRNA. Immunofluorescent detection of CYP1A indicated that induction of CYP1A by TCDD was localized within the cytoplasm of CEC cells. EROD activity and CYP1A4/5 mRNA levels were strongly induced in CEC and CEH cultures by TCDD and PCB 77, and the shapes of the concentration-response curves in CEC and CEH cultures were similar. The studies provide clear evidence that the AHR signaling pathway is induced by TCDD and PCB 77 in CEC, and establish a new in vitro approach for studying the effects of HAHs in the avian heart. Induction of CYP1A5 by TCDD in avian cardiomyocytes is a novel finding, and might help direct future studies on mechanisms of action of HAHs in the heart.
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Affiliation(s)
- Stephanie P Jones
- Environment Canada, National Wildlife Research Centre, 1125 Colonel By Drive, Ottawa, Ontario, Canada
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Matson CW, Timme-Laragy AR, Di Giulio RT. Fluoranthene, but not benzo[a]pyrene, interacts with hypoxia resulting in pericardial effusion and lordosis in developing zebrafish. CHEMOSPHERE 2008; 74:149-54. [PMID: 18840388 PMCID: PMC2644413 DOI: 10.1016/j.chemosphere.2008.08.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 08/04/2008] [Accepted: 08/13/2008] [Indexed: 05/02/2023]
Abstract
Previous research has documented several PAHs that interact synergistically, causing severe teratogenicity in developing fish embryos. The coexposure of CYP1A inhibitors (e.g. FL or ANF) with AHR agonists (e.g. BaP or BNF) results in a synergistic increase in toxicity. As with chemical CYP1A inhibitors, it has also been shown that CYP1A morpholinos exacerbate BNF-induced embryotoxicity. We hypothesized that a hypoxia-induced reduction in CYP1A activity in BNF or BaP-exposed zebrafish embryos would similarly enhance pericardial effusion and other developmental abnormalities. BaP, BNF, ANF, and FL exposures, both individually and as BaP+FL or BNF+ANF combinations, were performed under hypoxia and normoxia. CYP1A activity in the BaP+hypoxia and BNF+hypoxia embryos was reduced by approximately 60% relative to normoxia embryos. Although CYP1A activity was significantly reduced, we did not observe any increase in pericardial effusion in either group. An unexpected yet particularly interesting result of these experiments was the observed interaction of both FL and ANF with hypoxia. Relatively high, yet environmentally relevant concentrations of FL (100-500 microg L(-1)) interact with moderate hypoxia (7.3% DO) through an unknown mechanism, resulting in pericardial effusion and severe lordosis. Additionally, ANF exposures (100 microg L(-1)) which are not normally teratogenic caused dramatic pericardial effusion, but not lordosis, when embryos were coexposed to hypoxia. These results suggest that reduced CYP1A activity may not exclusively underlie observed developmental toxicity, and that hypoxia may exacerbate the developmental toxicity of some PAH mixtures.
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Affiliation(s)
| | | | - Richard T Di Giulio
- Corresponding Author: Richard T. Di Giulio, Nicholas School of the Environment, Duke University, Box 90328, Durham, NC 27708, Phone: (919) 613-8024, Fax: (919) 668-1799,
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34
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Scott JA, Hodson PV. Evidence for multiple mechanisms of toxicity in larval rainbow trout (Oncorhynchus mykiss) co-treated with retene and alpha-naphthoflavone. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2008; 88:200-206. [PMID: 18511136 DOI: 10.1016/j.aquatox.2008.04.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 04/09/2008] [Accepted: 04/11/2008] [Indexed: 05/26/2023]
Abstract
Alkylated polycyclic aromatic hydrocarbons, such as retene (7-isopropyl-1-methylphenanthrene), induce cytochrome P450 1A (CYP1A) enzymes and produce dioxin-like toxicity in the embryo-larval stages of fish characterized by the signs of blue sac disease (BSD). The signs of toxicity are well characterized; however, the mechanism is not well understood. To elucidate the role of CYP1A in retene toxicity, larval rainbow trout (Oncorhynchus mykiss) were co-treated with a range of concentrations of alpha-naphthoflavone (ANF), a known CYP1A inhibitor. The co-treatment produced synergistic toxicity at 3.2-100 microg/L ANF, after which toxicity at 180 microg/L ANF dropped to levels typical of retene-only. At 320 microg/L ANF, toxicity increased with or without retene, indicating that ANF alone was capable of inducing BSD. In addition, the additive toxicity of retene-only and 320 microg/L ANF-only approximately equalled that of the co-exposed larvae (100 microg/L retene+320 microg/L ANF), indicating response addition. Thus, two mechanisms of action occurred in co-exposed larvae at different concentrations of ANF. In trout larvae, there was a correlation between toxicity and CYP1A protein concentrations, and in juvenile trout, ANF produced a concentration-dependent inhibition of ethoxyresorufin-O-deethylase (EROD) activity without a measurable drop in CYP1A protein. Taken together, the mechanism underlying the synergistic toxicity is EROD-independent and may be AhR-dependent. This study demonstrated that multiple, exposure-dependent mechanisms can occur in mixture toxicity, suggesting that current risk assessment models may drastically underestimate toxicity, particularly of mixtures containing both CYP1A inducers and inhibitors.
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Affiliation(s)
- Jason A Scott
- Department of Biology, Queen's University, Kingston, ON, Canada
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35
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Hansen DA. Paternal environmental exposures and gene expression during spermatogenesis: Research review to research framework. ACTA ACUST UNITED AC 2008; 84:155-63. [DOI: 10.1002/bdrc.20121] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Billiard SM, Meyer JN, Wassenberg DM, Hodson PV, Di Giulio RT. Nonadditive effects of PAHs on Early Vertebrate Development: mechanisms and implications for risk assessment. Toxicol Sci 2007; 105:5-23. [PMID: 18156145 DOI: 10.1093/toxsci/kfm303] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants. Traditionally, much of the research has focused on the carcinogenic potential of specific PAHs, such as benzo(a)pyrene, but recent studies using sensitive fish models have shown that exposure to PAHs alters normal fish development. Some PAHs can induce a teratogenic phenotype similar to that caused by planar halogenated aromatic hydrocarbons, such as dioxin. Consequently, mechanism of action is often equated between the two classes of compounds. Unlike dioxins, however, the developmental toxicity of PAH mixtures is not necessarily additive. This is likely related to their multiple mechanisms of toxicity and their rapid biotransformation by CYP1 enzymes to metabolites with a wide array of structures and potential toxicities. This has important implications for risk assessment and management as the current approach for complex mixtures of PAHs usually assumes concentration addition. In this review we discuss our current knowledge of teratogenicity caused by single PAH compounds and by mixtures and the importance of these latest findings for adequately assessing risk of PAHs to humans and wildlife. Throughout, we place particular emphasis on research on the early life stages of fish, which has proven to be a sensitive and rapid developmental model to elucidate effects of hydrocarbon mixtures.
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Affiliation(s)
- Sonya M Billiard
- Health Canada, Health Products and Food Branch, Bureau of Chemical Safety, Ottawa, Ontario K1A0L2, Canada.
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Kulkarni AC, Kuppusamy P, Parinandi N. Oxygen, the lead actor in the pathophysiologic drama: enactment of the trinity of normoxia, hypoxia, and hyperoxia in disease and therapy. Antioxid Redox Signal 2007; 9:1717-30. [PMID: 17822371 DOI: 10.1089/ars.2007.1724] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Aerobic life has evolved a dependence on molecular oxygen for its mere survival. Mitochondrial oxidative phosphorylation absolutely requires oxygen to generate the currency of energy in aerobes. The physiologic homeostasis of these organisms is strictly maintained by optimal cellular and tissue-oxygenation status through complex oxygen-sensing mechanisms, signaling cascades, and transport processes. In the event of fluctuating oxygen levels leading to either an increase (hyperoxia) or decrease (hypoxia) in cellular oxygen, the organism faces a crisis involving depletion of energy reserves, altered cell-signaling cascades, oxidative reactions/events, and cell death or tissue damage. Molecular oxygen is activated by both nonenzymatic and enzymatic mechanisms into highly reactive oxygen species (ROS). Aerobes have evolved effective antioxidant defenses to counteract the reactivity of ROS. Although the ROS are also required for many normal physiologic functions of the aerobes, overwhelming production of ROS coupled with their insufficient scavenging by endogenous antioxidants will lead to detrimental oxidative stress. Needless to say, molecular oxygen is at the center of oxygenation, oxidative phosphorylation, and oxidative stress. This review focuses on the biology and pathophysiology of oxygen, with an emphasis on transport, sensing, and activation of oxygen, oxidative phosphorylation, oxygenation, oxidative stress, and oxygen therapy.
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Affiliation(s)
- Aditi C Kulkarni
- Center for Biomedical EPR Spectroscopy and Imaging, Comprehensive Cancer Center, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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Effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin administration and high-fat diet on the body weight and hepatic estrogen metabolism in female C3H/HeN mice. Toxicol Appl Pharmacol 2007; 226:107-18. [PMID: 17945325 DOI: 10.1016/j.taap.2007.08.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Revised: 08/23/2007] [Accepted: 08/23/2007] [Indexed: 12/23/2022]
Abstract
We studied the effect of administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) by i.p. injection once every 2 weeks in combination with a high-fat (HF) diet for 8 or 16 weeks on the body and organ weight changes as well as on the hepatic enzyme activity for estrogen metabolism in C3H/HeN female mice. Administration of TCDD at 100 microg/kg b.w. once every 2 weeks for 8 weeks increased the body weight by 46% in the HF diet-fed animals, but not in the regular diet-fed animals. This is the first observation suggesting that TCDD at a high dose (100 microg/kg b.w.), but not at lower doses (1 or 10 microg/kg b.w.), may have a strong obesity-inducing effect in C3H/HeN mice fed an HF diet. While TCDD increased liver weight and decreased thymus weight in animals, these effects were enhanced by feeding animals an HF diet. Metabolism studies showed that TCDD administration for 8 or 16 weeks increased the liver microsomal activity for the 2- and 4-hydroxylation of 17 beta-estradiol in animals fed a control diet, but surprisingly not in animals fed an HF diet. Treatment with TCDD dose-dependently increased the hepatic activity for the O-methylation of catechol estrogens in both control and HF diet-fed animals, and it also decreased the levels of liver microsomal sulfatase activity for hydrolysis of estrone-3-sulfate. TCDD did not significantly affect the hepatic enzyme activity for the glucuronidation or esterification of endogenous estrogens. It is suggested that enhanced metabolic inactivation of endogenous estrogens by hepatic estrogen-metabolizing enzymes in TCDD-treated, control diet-fed animals contributes importantly to the reduced incidence of estrogen-associated tumors in animals treated with TCDD.
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Jönsson ME, Jenny MJ, Woodin BR, Hahn ME, Stegeman JJ. Role of AHR2 in the expression of novel cytochrome P450 1 family genes, cell cycle genes, and morphological defects in developing zebra fish exposed to 3,3',4,4',5-pentachlorobiphenyl or 2,3,7,8-tetrachlorodibenzo-p-dioxin. Toxicol Sci 2007; 100:180-93. [PMID: 17686920 DOI: 10.1093/toxsci/kfm207] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Halogenated agonists for the aryl hydrocarbon receptor (AHR), such as 3,3',4,4',5-pentachlorobiphenyl (PCB126) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), cause developmental toxicity in fish. AHR dependence of these effects is known for TCDD but only presumed for PCB126, and the AHR-regulated genes involved are known only in part. We defined the role of AHR in regulation of four cytochrome P450 1 (CYP1) genes and the effect of PCB126 on cell cycle genes (i.e., PCNA and cyclin E) in zebra fish (Danio rerio) embryos. Basal and PCB126-induced expression of CYP1A, CYP1B1, CYP1C1, and CYP1C2 was examined over time as well as in relation to cell cycle gene expression and morphological effects of PCB126 in developing zebra fish. The four CYP1 genes differed in the time for maximal basal and induced expression, i.e., CYP1B1 peaked within 2 days postfertilization (dpf), the CYP1Cs around hatching (3 dpf), and CYP1A after hatching (14-21 dpf). These results indicate developmental periods when the CYP1s may play physiological roles. PCB126 (0.3-100nM) caused concentration-dependent CYP1 gene induction (EC50: 1.4-2.7nM, Lowest observed effect concentration [LOEC]: 0.3-1nM) and pericardial edema (EC50: 4.4nM, LOEC: 3nM) in 3-dpf embryos. Blockage of AHR2 translation significantly inhibited these effects of PCB126 and TCDD. PCNA gene expression was reduced by PCB126 in a concentration-dependent manner, suggesting that PCB126 could suppress cell proliferation. Our results indicate that the four CYP1 genes examined are regulated by AHR2 and that the effect of PCB126 on morphology in zebra fish embryos is AHR2 dependent. Moreover, the developmental patterns of expression and induction suggest that CYP1 enzymes could function in normal development and in developmental toxicity of PCB126 in fish embryos.
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MESH Headings
- Animals
- Aryl Hydrocarbon Hydroxylases/metabolism
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cell Proliferation/drug effects
- Craniofacial Abnormalities/chemically induced
- Craniofacial Abnormalities/metabolism
- Cyclin E/metabolism
- Cytochrome P-450 CYP1B1
- Cytochrome P-450 Enzyme System/genetics
- Cytochrome P-450 Enzyme System/metabolism
- Dose-Response Relationship, Drug
- Edema/chemically induced
- Edema/metabolism
- Embryo, Nonmammalian/abnormalities
- Embryo, Nonmammalian/drug effects
- Embryo, Nonmammalian/enzymology
- Embryo, Nonmammalian/metabolism
- Embryonic Development/drug effects
- Environmental Pollutants/toxicity
- Gene Expression Regulation, Developmental/drug effects
- Gene Expression Regulation, Enzymologic/drug effects
- Heart Defects, Congenital/chemically induced
- Heart Defects, Congenital/metabolism
- Isoenzymes/metabolism
- Oligonucleotides, Antisense/metabolism
- Polychlorinated Biphenyls/toxicity
- Polychlorinated Dibenzodioxins/toxicity
- Proliferating Cell Nuclear Antigen/metabolism
- Receptors, Aryl Hydrocarbon/agonists
- Receptors, Aryl Hydrocarbon/genetics
- Receptors, Aryl Hydrocarbon/metabolism
- Time Factors
- Transcriptional Activation
- Zebrafish/abnormalities
- Zebrafish/embryology
- Zebrafish/metabolism
- Zebrafish Proteins/agonists
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism
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Affiliation(s)
- Maria E Jönsson
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
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Clerk A, Giraldo A, Sugden PH. Chemotherapeutic agents and gene expression in cardiac myocytes. ACTA ACUST UNITED AC 2007; 47:140-53. [PMID: 17343902 DOI: 10.1016/j.advenzreg.2006.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Angela Clerk
- NHLI Division (Cardiac Medicine Section), Faculty of Medicine, Imperial College London, Flowers Building, Armstrong Road, London SW7 2AZ, UK.
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