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Eaton DL, Simon TW, Kaminski NE, Perdew GH, Nebert DW. The 2022 revised WHO TEFs for dioxins and dioxin-like chemicals: The importance of considering the use of species-specific information to determine relative effective potency for human-based risk assessment. Regul Toxicol Pharmacol 2024; 149:105599. [PMID: 38490576 DOI: 10.1016/j.yrtph.2024.105599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 02/25/2024] [Accepted: 03/05/2024] [Indexed: 03/17/2024]
Affiliation(s)
- David L Eaton
- Dept. Environmental Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA.
| | | | - Norbert E Kaminski
- Food and Consumer Product Ingredient Safety Endowed Chair, Department of Pharmacology and Toxicology, Institute for Integrative Toxicology, Director, Center for Reseaerch on Ingredient Safety, Michigan State University, East Lansing, MI, USA
| | - Gary H Perdew
- H. Thomas and Dorothy Willits Hallowell Chair in Agricultural Sciences, The Pennsylvania State University, State College, PA, USA
| | - Daniel W Nebert
- Department of Environmental and Public Health Sciences, Center for Environmental Genetics, University of Cincinnati College of Medicine, Department of Pediatrics & Molecular Developmental Biology, Division of Human Genetics, Cincinnati Children's Research Foundation, Cincinnati, OH, USA
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2
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Li K, Li K, He Y, Liang S, Shui X, Lei W. Aryl hydrocarbon receptor: A bridge linking immuno-inflammation and metabolism in atherosclerosis. Biochem Pharmacol 2023; 216:115744. [PMID: 37579858 DOI: 10.1016/j.bcp.2023.115744] [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: 05/26/2023] [Revised: 08/08/2023] [Accepted: 08/09/2023] [Indexed: 08/16/2023]
Abstract
Cardiovascular disease is the leading cause of death worldwide, and atherosclerosis is a major contributor to this etiology. The ligand-activated transcription factor, known as the aryl hydrocarbon receptor (AhR), plays an essential role in the interactions between genes and the environment. In a number of human diseases, including atherosclerosis, the AhR signaling pathway has recently been shown to be aberrantly expressed and activated. It's reported that AhR can regulate the immuno-inflammatory response and metabolism pathways in atherosclerosis, potentially serving as a bridge that links these processes. In this review, we highlight the involvement of AhR in atherosclerosis. From the literature, we conclude that AhR is a potential target for controlling atherosclerosis through precise interventions.
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Affiliation(s)
- Kongwei Li
- Guangdong Provincial Engineering Technology Research Center for Molecular Diagnosis and Innovative Drugs Translation of Cardiopulmonary Vascular Diseases, University Joint Laboratory of Guangdong Province and Macao Region on Molecular Targets and Intervention of Cardiovascular Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China; Cardiovascular Medicine Center, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China; Department of Precision Laboratory, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China
| | - Kaiyue Li
- Guangdong Provincial Engineering Technology Research Center for Molecular Diagnosis and Innovative Drugs Translation of Cardiopulmonary Vascular Diseases, University Joint Laboratory of Guangdong Province and Macao Region on Molecular Targets and Intervention of Cardiovascular Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China; Department of Precision Laboratory, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China
| | - Yuan He
- Guangdong Provincial Engineering Technology Research Center for Molecular Diagnosis and Innovative Drugs Translation of Cardiopulmonary Vascular Diseases, University Joint Laboratory of Guangdong Province and Macao Region on Molecular Targets and Intervention of Cardiovascular Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China; Laboratory of Cardiovascular Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China
| | - Shan Liang
- Guangdong Provincial Engineering Technology Research Center for Molecular Diagnosis and Innovative Drugs Translation of Cardiopulmonary Vascular Diseases, University Joint Laboratory of Guangdong Province and Macao Region on Molecular Targets and Intervention of Cardiovascular Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China; Cardiovascular Medicine Center, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China; Department of Precision Laboratory, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China
| | - Xiaorong Shui
- Guangdong Provincial Engineering Technology Research Center for Molecular Diagnosis and Innovative Drugs Translation of Cardiopulmonary Vascular Diseases, University Joint Laboratory of Guangdong Province and Macao Region on Molecular Targets and Intervention of Cardiovascular Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China; Laboratory of Vascular Surgery, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China.
| | - Wei Lei
- Guangdong Provincial Engineering Technology Research Center for Molecular Diagnosis and Innovative Drugs Translation of Cardiopulmonary Vascular Diseases, University Joint Laboratory of Guangdong Province and Macao Region on Molecular Targets and Intervention of Cardiovascular Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China; Department of Precision Laboratory, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China.
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Grishanova AY, Perepechaeva ML. Aryl Hydrocarbon Receptor in Oxidative Stress as a Double Agent and Its Biological and Therapeutic Significance. Int J Mol Sci 2022; 23:ijms23126719. [PMID: 35743162 PMCID: PMC9224361 DOI: 10.3390/ijms23126719] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/14/2022] [Accepted: 06/14/2022] [Indexed: 12/02/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR) has long been implicated in the induction of a battery of genes involved in the metabolism of xenobiotics and endogenous compounds. AhR is a ligand-activated transcription factor necessary for the launch of transcriptional responses important in health and disease. In past decades, evidence has accumulated that AhR is associated with the cellular response to oxidative stress, and this property of AhR must be taken into account during investigations into a mechanism of action of xenobiotics that is able to activate AhR or that is susceptible to metabolic activation by enzymes encoded by the genes that are under the control of AhR. In this review, we examine various mechanisms by which AhR takes part in the oxidative-stress response, including antioxidant and prooxidant enzymes and cytochrome P450. We also show that AhR, as a participant in the redox balance and as a modulator of redox signals, is being increasingly studied as a target for a new class of therapeutic compounds and as an explanation for the pathogenesis of some disorders.
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Han DT, Zhao W, Powell WH. Dioxin Disrupts Thyroid Hormone and Glucocorticoid Induction of klf9, a Master Regulator of Frog Metamorphosis. Toxicol Sci 2022; 187:150-161. [PMID: 35172007 PMCID: PMC9041550 DOI: 10.1093/toxsci/kfac017] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Frog metamorphosis, the development of an air-breathing froglet from an aquatic tadpole, is controlled by thyroid hormone (TH) and glucocorticoids (GC). Metamorphosis is susceptible to disruption by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an aryl hydrocarbon receptor (AHR) agonist. Krüppel-like factor 9 (klf9), an immediate early gene in the endocrine-controlled cascade of expression changes governing metamorphosis, can be synergistically induced by both hormones. This process is mediated by an upstream enhancer cluster, the klf9 synergy module (KSM). klf9 is also an AHR target. We measured klf9 mRNA following exposures to triiodothyronine (T3), corticosterone (CORT), and TCDD in the Xenopus laevis cell line XLK-WG. klf9 was induced 6-fold by 50 nM T3, 4-fold by 100 nM CORT, and 3-fold by 175 nM TCDD. Cotreatments of CORT and TCDD or T3 and TCDD induced klf9 7- and 11-fold, respectively, whereas treatment with all 3 agents induced a 15-fold increase. Transactivation assays examined enhancers from the Xenopus tropicalis klf9 upstream region. KSM-containing segments mediated a strong T3 response and a larger T3/CORT response, whereas induction by TCDD was mediated by a region ∼1 kb farther upstream containing 5 AHR response elements (AHREs). This region also supported a CORT response in the absence of readily identifiable GC responsive elements, suggesting mediation by protein-protein interactions. A functional AHRE cluster is positionally conserved in the human genome, and klf9 was induced by TCDD and TH in HepG2 cells. These results indicate that AHR binding to upstream AHREs represents an early key event in TCDD's disruption of endocrine-regulated klf9 expression and metamorphosis.
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Affiliation(s)
| | | | - Wade H Powell
- To whom correspondence should be addressed at Biology Department, Kenyon College, 202 N College Rd, Gambier, OH 43022. E-mail:
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Xu X, Zhang X, Yuan Y, Zhao Y, Fares HM, Yang M, Wen Q, Taha R, Sun L. Species-Specific Differences in Aryl Hydrocarbon Receptor Responses: How and Why? Int J Mol Sci 2021; 22:ijms222413293. [PMID: 34948089 PMCID: PMC8708342 DOI: 10.3390/ijms222413293] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/19/2021] [Accepted: 12/03/2021] [Indexed: 12/16/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR) is a transcription factor that regulates a wide range of biological and toxicological effects by binding to specific ligands. AhR ligands exist in various internal and external ecological systems, such as in a wide variety of hydrophobic environmental contaminants and naturally occurring chemicals. Most of these ligands have shown differential responses among different species. Understanding the differences and their mechanisms helps in designing better experimental animal models, improves our understanding of the environmental toxicants related to AhR, and helps to screen and develop new drugs. This review systematically discusses the species differences in AhR activation effects and their modes of action. We focus on the species differences following AhR activation from two aspects: (1) the molecular configuration and activation of AhR and (2) the contrast of cis-acting elements corresponding to AhR. The variations in the responses seen in humans and other species following the activation of the AhR signaling pathway can be attributed to both factors.
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Affiliation(s)
- Xiaoting Xu
- Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing 210009, China; (X.X.); (X.Z.); (Y.Y.); (Y.Z.); (H.M.F.); (M.Y.); (Q.W.); (R.T.)
| | - Xi Zhang
- Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing 210009, China; (X.X.); (X.Z.); (Y.Y.); (Y.Z.); (H.M.F.); (M.Y.); (Q.W.); (R.T.)
| | - Yuzhu Yuan
- Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing 210009, China; (X.X.); (X.Z.); (Y.Y.); (Y.Z.); (H.M.F.); (M.Y.); (Q.W.); (R.T.)
| | - Yongrui Zhao
- Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing 210009, China; (X.X.); (X.Z.); (Y.Y.); (Y.Z.); (H.M.F.); (M.Y.); (Q.W.); (R.T.)
| | - Hamza M. Fares
- Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing 210009, China; (X.X.); (X.Z.); (Y.Y.); (Y.Z.); (H.M.F.); (M.Y.); (Q.W.); (R.T.)
| | - Mengjiao Yang
- Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing 210009, China; (X.X.); (X.Z.); (Y.Y.); (Y.Z.); (H.M.F.); (M.Y.); (Q.W.); (R.T.)
| | - Qing Wen
- Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing 210009, China; (X.X.); (X.Z.); (Y.Y.); (Y.Z.); (H.M.F.); (M.Y.); (Q.W.); (R.T.)
| | - Reham Taha
- Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing 210009, China; (X.X.); (X.Z.); (Y.Y.); (Y.Z.); (H.M.F.); (M.Y.); (Q.W.); (R.T.)
| | - Lixin Sun
- Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing 210009, China; (X.X.); (X.Z.); (Y.Y.); (Y.Z.); (H.M.F.); (M.Y.); (Q.W.); (R.T.)
- Key Laboratory of Drug Quality Control and Pharmacovigilance, China Pharmaceutical University, Ministry of Education, Nanjing 210009, China
- Correspondence: ; Tel.: +86-151-9599-9925
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Yan L, Messner CJ, Zhang X, Suter-Dick L. Assessment of fibrotic pathways induced by environmental chemicals using 3D-human liver microtissue model. ENVIRONMENTAL RESEARCH 2021; 194:110679. [PMID: 33387535 DOI: 10.1016/j.envres.2020.110679] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 06/12/2023]
Abstract
Exposure to environmental chemicals, particularly those with persistent and bioaccumulative properties have been linked to liver diseases. Induction of fibrotic pathways is considered as a pre-requirement of chemical induced liver fibrosis. Here, we applied 3D in vitro human liver microtissues (MTs) composed of HepaRG, THP-1 and hTERT-HSC that express relevant hepatic pathways (bile acid, sterol, and xenobiotic metabolism) and can recapitulate key events of liver fibrosis (e.g. extracellular matrix-deposition). The liver MTs were exposed to a known profibrotic chemical, thioacetamide (TAA) and three representative environmental chemicals (TCDD, benzo [a] pyrene (BaP) and PCB126). Both TAA and BaP triggered fibrotic pathway related events such as hepatocellular damage (cytotoxicity and decreased albumin release), hepatic stellate cell activation (transcriptional upregulation of α-SMA and Col1α1) and extracellular matrix remodelling. TCDD or PCB126 at measured concentrations did not elicit these responses in the 3D liver MTs system, though they caused cytotoxicity in HepaRG monoculture at high concentrations. Reduced human transcriptome (RHT) analysis captured molecular responses involved in liver fibrosis when MTs were treated with TAA and BaP. The results suggest that 3D, multicellular, human liver microtissues represent an alternative, human-relevant, in vitro liver model for assessing fibrotic pathways induced by environmental chemicals.
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Affiliation(s)
- Lu Yan
- State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Catherine Jane Messner
- School of Life Sciences, University of Applied Sciences Northwestern Switzerland, Muttenz, 4132, Switzerland; Department of Pharmaceutical Sciences, University of Basel, Basel, 4003, Switzerland; Swiss Centre for Applied Human Toxicology (SCAHT), 4056, Switzerland
| | - Xiaowei Zhang
- State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China.
| | - Laura Suter-Dick
- School of Life Sciences, University of Applied Sciences Northwestern Switzerland, Muttenz, 4132, Switzerland; Swiss Centre for Applied Human Toxicology (SCAHT), 4056, Switzerland
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Sharma D, Rani P, Onteru SK, Roy P, Tyagi RK, Singh SP, Singh D. Reverse transcription-loop mediated isothermal amplification (RT-LAMP) assay for detection of AhR receptor responsive xenobiotics. Toxicol Mech Methods 2021; 31:359-366. [PMID: 33563076 DOI: 10.1080/15376516.2021.1884923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Dioxins are a group of highly toxic environmental persistent organic pollutants, which are lipophilic in nature. 2, 3, 7, 8- tetrachlorodibenzo-p-dioxin (TCDD) is the most toxic representative of this class. TCDD causes several human health effects like endocrine disruption, carcinogenesis and reproductive toxicity mediated by aryl-hydrocarbon receptor. Current detection methods of dioxins like gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry etc. are costly and time consuming. Therefore, the present study aims to develop a relatively faster and cheaper technique called reverse transcription-loop mediated isothermal amplification (RT-LAMP) assay to detect dioxins. Cultured granulosa cells used as a model system were treated with different doses (5, 10 and 15 pg/mL) of aryl hydrocarbon receptor (AhR)responsive xenobiotic, TCDD, in accordance with maximum residue limit values. Cells were treated for 6, 12 and 24 h, respectively to study the gene expression of TCDD receptor called AhR and AhR responsive genes, CYP1A1 and CYP1B1, in a dose and time dependent manner. All targeted genes expression significantly increased after 6 and 12 h by 1.3-8 folds. For the development of RT-LAMP assay, CYP1A1 gene was used with 6 h TCDD treatment. RT-LAMP assay was standardized with optimal color change at 30 min using 50 ng of cellular RNA. In all the cases, we could distinguish RT-LAMP-positive condition from one sample to another sample due to intensity of color. The method was also validated by spectrometric method. In conclusion, the developed method will be used to screen AhR receptor responsive xenobiotics by observing the color change in RT-LAMP assay like dioxin used in the present study.
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Affiliation(s)
- Deeksha Sharma
- Molecular Endocrinology, Functional Genomics and Systems Biology Laboratory, Animal Biochemistry Division, National Dairy Research Institute, Karnal, India
| | - Payal Rani
- Molecular Endocrinology, Functional Genomics and Systems Biology Laboratory, Animal Biochemistry Division, National Dairy Research Institute, Karnal, India
| | - Suneel Kumar Onteru
- Molecular Endocrinology, Functional Genomics and Systems Biology Laboratory, Animal Biochemistry Division, National Dairy Research Institute, Karnal, India
| | - Partha Roy
- Molecular Endocrinology, Functional Genomics and Systems Biology Laboratory, Animal Biochemistry Division, National Dairy Research Institute, Karnal, India
| | - Rakesh Kumar Tyagi
- Molecular Endocrinology, Functional Genomics and Systems Biology Laboratory, Animal Biochemistry Division, National Dairy Research Institute, Karnal, India
| | - Surya Pratap Singh
- Molecular Endocrinology, Functional Genomics and Systems Biology Laboratory, Animal Biochemistry Division, National Dairy Research Institute, Karnal, India
| | - Dheer Singh
- Molecular Endocrinology, Functional Genomics and Systems Biology Laboratory, Animal Biochemistry Division, National Dairy Research Institute, Karnal, India
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Doan TQ, Connolly L, Igout A, Muller M, Scippo ML. In vitro differential responses of rat and human aryl hydrocarbon receptor to two distinct ligands and to different polyphenols. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 265:114966. [PMID: 32563119 DOI: 10.1016/j.envpol.2020.114966] [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: 04/05/2020] [Revised: 05/27/2020] [Accepted: 06/03/2020] [Indexed: 06/11/2023]
Abstract
TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and several other environment/food-borne toxic compounds induce their toxicity via the aryl hydrocarbon receptor (AhR). AhR is also modulated by various endogenous ligands e.g. highly potent tryptophan (Trp)-derivative FICZ (6-formylindolo[3,2-b]carbazole) and natural ligands abundant in the human diet e.g. polyphenols. Therefore, evaluating AhR species-specific responses is crucial for understanding AhR physiological functions, establishing risk assessments, and exploring the applicability of AhR mediators in drug and food industry towards human-based usages. We studied AhR transactivation of FICZ/TCDD in vitro in a time-dependent and species-specific manner using dioxin responsive luciferase reporter gene assays derived from rat (DR-H4IIE) and human (DR-HepG2) hepatoma cells. We observed for the first time that FICZ potency was similar in both cell lines and was 40 times higher than TCDD in DR-HepG2 cells. Depleting Trp-derivative endogenously produced ligands by using culture medium without Trp, resulted in 3-fold higher AhR activation upon adding FICZ in DR-H4IIE cells, in contrast to DR-HepG2 cells which revealed a fast degradation of FICZ induction from 10 h post-exposure to complete disappearance after 24 h. Seven polyphenols and a mixture thereof, chosen based on commercially recommended doses and adjusted to human realistic exposure, caused rat and human species-specific AhR responses. Two isoflavones (daidzein and genistein) induced rat AhR synergistic effects with FICZ and/or TCDD, while quercetin, chrysin, curcumin, resveratrol, and the mixture exerted a strong inhibitory effect on the human AhR. Strikingly, resveratrol and quercetin at their realistic nanomolar concentrations acted additively in the mixture to abolish human AhR activation induced by various TCDD concentrations. Taken together, these results illustrate the species-specific complexity of AhR transcriptional activities modulated by various ligands and highlight the need for studies of human-based approaches.
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Affiliation(s)
- T Q Doan
- Laboratory of Food Analysis, FARAH-Veterinary Public Health, University of Liège, Liège, 4000, Belgium
| | - L Connolly
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Northern Ireland, BT9 5DL, UK
| | - A Igout
- Department of Biomedical and Preclinical Sciences, University of Liège, Liège, 4000, Belgium
| | - M Muller
- GIGA-R, Laboratory for Organogenesis and Regeneration, University of Liège, Liège, 4000, Belgium
| | - M L Scippo
- Laboratory of Food Analysis, FARAH-Veterinary Public Health, University of Liège, Liège, 4000, Belgium.
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Vogel CFA, Van Winkle LS, Esser C, Haarmann-Stemmann T. The aryl hydrocarbon receptor as a target of environmental stressors - Implications for pollution mediated stress and inflammatory responses. Redox Biol 2020; 34:101530. [PMID: 32354640 PMCID: PMC7327980 DOI: 10.1016/j.redox.2020.101530] [Citation(s) in RCA: 206] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/20/2020] [Accepted: 03/31/2020] [Indexed: 02/08/2023] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor regulating the expression of genes, for instance encoding the monooxygenases cytochrome P450 (CYP) 1A1 and CYP1A2, which are important enzymes in metabolism of xenobiotics. The AHR is activated upon binding of polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants (POPs), and related ubiquitous environmental chemicals, to mediate their biological and toxic effects. In addition, several endogenous and natural compounds can bind to AHR, thereby modulating a variety of physiological processes. In recent years, ambient particulate matter (PM) associated with traffic related air pollution (TRAP) has been found to contain significant amounts of PAHs. PM containing PAHs are of increasing concern as a class of agonists, which can activate the AHR. Several reports show that PM and AHR-mediated induction of CYP1A1 results in excessive generation of reactive oxygen species (ROS), causing oxidative stress. Furthermore, exposure to PM and PAHs induce inflammatory responses and may lead to chronic inflammatory diseases, including asthma, cardiovascular diseases, and increased cancer risk. In this review, we summarize findings showing the critical role that the AHR plays in mediating effects of environmental pollutants and stressors, which pose a risk of impacting the environment and human health. PAHs present on ambient air pollution particles are ligands of the cellular AHR. AHR-dependent induction of CYP1, AKR, NOX and COX-2 genes can be a source of ROS generation. AHR signaling and NRF2 signaling interact to regulate the expression of antioxidant genes. Air pollution and ROS can affect inflammation, which is partially triggered by AHR and associated immune responses. Skin, lung, and the cardiovascular system are major target sites for air pollution-induced inflammation.
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Affiliation(s)
- Christoph F A Vogel
- Center for Health and the Environment, University of California, One Shields Avenue, Davis, CA, 95616, USA; Department of Environmental Toxicology, University of California, One Shields Avenue, Davis, CA, 95616, USA
| | - Laura S Van Winkle
- Center for Health and the Environment, University of California, One Shields Avenue, Davis, CA, 95616, USA; School of Veterinary Medicine Department of Anatomy, University of California, One Shields Avenue, Davis, CA, 5616, USA
| | - Charlotte Esser
- IUF - Leibniz-Research Institute for Environmental Medicine, 40225, Düsseldorf, Germany
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Rawls KD, Blais EM, Dougherty BV, Vinnakota KC, Pannala VR, Wallqvist A, Kolling GL, Papin JA. Genome-Scale Characterization of Toxicity-Induced Metabolic Alterations in Primary Hepatocytes. Toxicol Sci 2019; 172:279-291. [PMID: 31501904 PMCID: PMC6876259 DOI: 10.1093/toxsci/kfz197] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Context-specific GEnome-scale metabolic Network REconstructions (GENREs) provide a means to understand cellular metabolism at a deeper level of physiological detail. Here, we use transcriptomics data from chemically-exposed rat hepatocytes to constrain a GENRE of rat hepatocyte metabolism and predict biomarkers of liver toxicity using the Transcriptionally Inferred Metabolic Biomarker Response algorithm. We profiled alterations in cellular hepatocyte metabolism following in vitro exposure to four toxicants (acetaminophen, carbon tetrachloride, 2,3,7,8-tetrachlorodibenzodioxin, and trichloroethylene) for six hour. TIMBR predictions were compared with paired fresh and spent media metabolomics data from the same exposure conditions. Agreement between computational model predictions and experimental data led to the identification of specific metabolites and thus metabolic pathways associated with toxicant exposure. Here, we identified changes in the TCA metabolites citrate and alpha-ketoglutarate along with changes in carbohydrate metabolism and interruptions in ATP production and the TCA Cycle. Where predictions and experimental data disagreed, we identified testable hypotheses to reconcile differences between the model predictions and experimental data. The presented pipeline for using paired transcriptomics and metabolomics data provides a framework for interrogating multiple omics datasets to generate mechanistic insight of metabolic changes associated with toxicological responses.
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Affiliation(s)
- Kristopher D Rawls
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908
| | - Edik M Blais
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908
| | - Bonnie V Dougherty
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908
| | - Kalyan C Vinnakota
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc. (HJF), Bethesda, Maryland 20817
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Fort Detrick, Maryland 21702
| | - Venkat R Pannala
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc. (HJF), Bethesda, Maryland 20817
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Fort Detrick, Maryland 21702
| | - Anders Wallqvist
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Fort Detrick, Maryland 21702
| | - Glynis L Kolling
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908
- Department of Medicine, Division of Infectious Diseases and International Health
| | - Jason A Papin
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908
- Department of Medicine, Division of Infectious Diseases and International Health
- Department of Biochemistry & Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908
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11
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Zhang Z, Liu W, Hu J, Qu Y, Zhao J, Pan Y, Zhang X, Quan X. Surface water extracts impair gene profiles and differentiation in human mesenchymal stem cells. ENVIRONMENT INTERNATIONAL 2019; 132:104823. [PMID: 31445443 DOI: 10.1016/j.envint.2019.05.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/18/2019] [Accepted: 05/08/2019] [Indexed: 06/10/2023]
Abstract
Low concentrations of pollutants in surface water challenge the assessment of chronic effects on human health. Human bone mesenchymal stem cells (hBMSCs) were employed as a sensitive and relevant in vitro model to evaluate the potential biological effects caused by mixtures of pollutants in surface water. Organic extracts of surface water collected from Hun River inhibited cell viability in a dose-dependent manner. Surface water extracts at noncytotoxic concentrations induced 533 to 1055 differentially expressed genes (DEGs) in hBMSCs after 48 h of exposure. Total of 370 genes were commonly affected by surface water from different sites and accounted for 35-69% of DEGs impaired by individual sample. Pathways related to human diseases, genetic information processing and organismal systems were enriched based on DEGs. Interleukins (IL1B, IL6 and IL8) were affected and involved in most human diseases related pathways. The significantly downregulation of COL1A1 and the variation of rheumatoid arthritis pathway suggested that surface water potentially inhibited osteogenic differentiation of hBMSCs. Clustering analysis and principle component analysis with DEGs distinguish the surface water from tributary and mainstream. The crossing-species comparison of transcriptomic changes identified 923 and 2715 differentially expressed orthologs in hBMSCs and zebrafish, respectively. After the exposure ceased, the followed osteogenic and adipogenic differentiation in hBMSCs for 14 days were inhibited by the treatment of surface water during undifferentiated period, whereas the non-polar fraction exhibited stronger potency in affecting differentiation than the mid to polar fractions. hBMSCs, combining unsupervised transcriptomic technique and specific endpoints test, are promising in screening the health effects of environmental mixtures in surface water.
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Affiliation(s)
- Zhou Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Wei Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
| | - Junxiang Hu
- Liaoning Environmental Monitoring Experiment Center, Shenyang 110031, China
| | - Yuanyuan Qu
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Jing Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Yifan Pan
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Xin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Xie Quan
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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12
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Tischkau SA. Mechanisms of circadian clock interactions with aryl hydrocarbon receptor signalling. Eur J Neurosci 2019; 51:379-395. [DOI: 10.1111/ejn.14361] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 01/17/2019] [Accepted: 01/23/2019] [Indexed: 12/29/2022]
Affiliation(s)
- Shelley A. Tischkau
- Department of PharmacologySouthern Illinois University School of Medicine Springfield Illinois
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13
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Fu H, Wang L, Wang J, Bennett BD, Li JL, Zhao B, Hu G. Dioxin and AHR impairs mesoderm gene expression and cardiac differentiation in human embryonic stem cells. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 651:1038-1046. [PMID: 30266049 PMCID: PMC6547817 DOI: 10.1016/j.scitotenv.2018.09.247] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 09/18/2018] [Accepted: 09/19/2018] [Indexed: 05/21/2023]
Abstract
Dioxin and dioxin-related polychlorinated biphenyls are potent toxicants with association with developmental heart defects and congenital heart diseases. However, the underlying mechanism of their developmental toxicity is not fully understood. Further, different animals show distinct susceptibility and phenotypes after exposure, suggesting possible species-specific effects. Using a human embryonic stem cell (ESC) cardiomyocyte differentiation model, we examined the impact, susceptible window, and dosage of 2,3,7,8‑tetrachlorodibenzo‑p‑dioxin (TCDD) on human cardiac development. We showed that treatment of human ESCs with TCDD at the ESC stage inhibits cardiomyocyte differentiation, and the effect is largely mediated by the aryl hydrocarbon receptor (AHR). We further identified genes that are differentially expressed after TCDD treatment by RNA-sequencing, and genomic regions that are occupied by AHR by chromatin immunoprecipitation and high-throughput sequencing. Our results support the model that TCDD impairs human ESC cardiac differentiation by promoting AHR binding and repression of key mesoderm genes. More importantly, our study demonstrates the toxicity of dioxin in human embryonic development and uncovered a novel mechanism by which dioxin and AHR regulates lineage commitment. It also illustrates the power of ESC-based models in the systematic study of developmental toxicology.
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Affiliation(s)
- Hualing Fu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
| | - Li Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jiajia Wang
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Brian D Bennett
- Integrative Bioinformatics, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Jian-Liang Li
- Integrative Bioinformatics, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Bin Zhao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China.
| | - Guang Hu
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
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14
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Strapáčová S, Brenerová P, Krčmář P, Andersson P, van Ede KI, van Duursen MB, van den Berg M, Vondráček J, Machala M. Relative effective potencies of dioxin-like compounds in rodent and human lung cell models. Toxicology 2018; 404-405:33-41. [DOI: 10.1016/j.tox.2018.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/11/2018] [Accepted: 05/02/2018] [Indexed: 12/23/2022]
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15
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Suh KS, Choi EM, Jung WW, Park SY, Chin SO, Rhee SY, Pak YK, Chon S. 27-Deoxyactein prevents 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced cellular damage in MC3T3-E1 osteoblastic cells. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2018; 53:561-570. [PMID: 29364047 DOI: 10.1080/10934529.2018.1428275] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a well-known environmental contaminant that exerts its toxicity through a variety of signaling mechanisms. The present study evaluated the effects of 27-deoxyactein, one of the major constituents isolated from Cimicifuga racemosa, on TCDD-induced toxicity in osteoblastic MC3T3-E1 cells. TCDD reduced cell survival, markedly increased apoptosis, and enhanced autophagy activity. However, pre-treatment with 27-deoxyactein attenuated all TCDD-induced effects and significantly decreased intracellular calcium (Ca2+) concentrations, the collapse of the mitochondrial membrane potential (MMP), the level of reactive oxygen species (ROS), and cardiolipin peroxidation compared to the TCDD-treated controls. Additionally, TCDD-induced increases in the levels of aryl hydrocarbon receptor (AhR), cytochrome P450 1A1 (CYP1A1), and extracellular signal-regulated kinase (ERK) were significantly inhibited by 27-deoxyactein. The mRNA levels of superoxide dismutase (SOD), ERK1, and nuclear factor kappa B (NF-κB) were also effectively restored by pre-treatment with 27-deoxyactein. Furthermore, 27-deoxyactein significantly increased the expressions of genes associated with osteoblast differentiation, including alkaline phosphatase (ALP), osteocalcin, bone sialoprotein (BSP), and osterix. Taken together, the present findings demonstrate the preventive effects of 27-deoxyactein on TCDD-induced damage in osteoblasts.
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Affiliation(s)
- Kwang Sik Suh
- a Department of Endocrinology & Metabolism , School of Medicine, Kyung Hee University , Seoul , Republic of Korea
| | - Eun Mi Choi
- a Department of Endocrinology & Metabolism , School of Medicine, Kyung Hee University , Seoul , Republic of Korea
| | - Woon-Won Jung
- b Department of Biomedical Laboratory Science , College of Health Sciences, Cheongju University , Cheongju , Chungbuk , Republic of Korea
| | - So Young Park
- c Department of Medicine , Graduate School, Kyung Hee University , Seoul , Republic of Korea
| | - Sang Ouk Chin
- a Department of Endocrinology & Metabolism , School of Medicine, Kyung Hee University , Seoul , Republic of Korea
| | - Sang Youl Rhee
- a Department of Endocrinology & Metabolism , School of Medicine, Kyung Hee University , Seoul , Republic of Korea
| | - Youngmi Kim Pak
- d Department of Physiology , School of Medicine, Kyung Hee University , Seoul , Republic of Korea
| | - Suk Chon
- a Department of Endocrinology & Metabolism , School of Medicine, Kyung Hee University , Seoul , Republic of Korea
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16
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Fader KA, Zacharewski TR. Beyond the Aryl Hydrocarbon Receptor: Pathway Interactions in the Hepatotoxicity of 2,3,7,8-Tetrachlorodibenzo- p-dioxin and Related Compounds. CURRENT OPINION IN TOXICOLOGY 2017; 2:36-41. [PMID: 28948239 PMCID: PMC5609723 DOI: 10.1016/j.cotox.2017.01.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is the prototypical ligand for a group of environmental halogenated aromatic hydrocarbon contaminants which elicit hepatotoxicity and other toxic responses through activation of the aryl hydrocarbon receptor (AhR). Despite the conservation of the AhR and its signaling pathway, TCDD-elicited differential gene expression networks are species-specific, consistent with differences in sensitivity and toxic responses between species. This review integrates gene expression studies with complementary phenotypic analyses (e.g., metabolomics, clinical biochemistry, and histopathology) to elucidate the pathways through which TCDD and related compounds cause hepatotoxicity beyond AhR activation. We propose that AhR-mediated toxicity is a collective response to the cumulative burden of metabolic reprogramming across multiple pathways. Consequently, nutrition, health status, and genetic background establish the basis for differences in sensitivity and predisposition to adverse outcomes between species, sub-populations, tissues, and cells.
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Affiliation(s)
- Kelly A. Fader
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, 48824
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824
| | - Timothy R. Zacharewski
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, 48824
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824
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17
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Kovalova N, Nault R, Crawford R, Zacharewski TR, Kaminski NE. Comparative analysis of TCDD-induced AhR-mediated gene expression in human, mouse and rat primary B cells. Toxicol Appl Pharmacol 2016; 316:95-106. [PMID: 27913140 DOI: 10.1016/j.taap.2016.11.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 11/16/2016] [Accepted: 11/18/2016] [Indexed: 12/21/2022]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental pollutant that activates the aryl hydrocarbon receptor (AhR) resulting in altered gene expression. In vivo, in vitro, and ex vivo studies have demonstrated that B cells are directly impaired by TCDD, and are a sensitive target as evidenced by suppression of antibody responses. The window of sensitivity to TCDD-induced suppression of IgM secretion among mouse, rat and human B cells is similar. Specifically, TCDD must be present within the initial 12h post B cell stimulation, indicating that TCDD disrupts early signaling network(s) necessary for B lymphocyte activation and differentiation. Therefore, we hypothesized that TCDD treatment across three different species (mouse, rat and human) triggers a conserved, B cell-specific mechanism that is involved in TCDD-induced immunosuppression. RNA sequencing (RNA-Seq) was used to identify B cell-specific orthologous genes that are differentially expressed in response to TCDD in primary mouse, rat and human B cells. Time course studies identified TCDD-elicited differential expression of 515 human, 2371 mouse and 712 rat orthologous genes over the 24-h period. 28 orthologs were differentially expressed in response to TCDD in all three species. Overrepresented pathways enriched in all three species included cytokine-cytokine receptor interaction, ECM-receptor interaction, focal adhesion, regulation of actin cytoskeleton and pathways in cancer. Differentially expressed genes functionally associated with cell-cell signaling in humans, immune response in mice, and oxidation reduction in rats. Overall, these results suggest that despite the conservation of the AhR and its signaling mechanism, TCDD elicits species-specific gene expression changes.
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Affiliation(s)
- Natalia Kovalova
- Department of Pharmacology and Toxicology, Michigan State University, Lansing, MI 48824, USA; Institute for Integrative Toxicology, Michigan State University, Lansing, MI 48824, USA.
| | - Rance Nault
- Institute for Integrative Toxicology, Michigan State University, Lansing, MI 48824, USA; Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.
| | - Robert Crawford
- Institute for Integrative Toxicology, Michigan State University, Lansing, MI 48824, USA.
| | - Timothy R Zacharewski
- Institute for Integrative Toxicology, Michigan State University, Lansing, MI 48824, USA; Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.
| | - Norbert E Kaminski
- Department of Pharmacology and Toxicology, Michigan State University, Lansing, MI 48824, USA; Institute for Integrative Toxicology, Michigan State University, Lansing, MI 48824, USA.
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18
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Evaluation of toxicological biomarkers in secreted proteins of HepG2 cells exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin and their expressions in the plasma of rats and incineration workers. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:584-93. [DOI: 10.1016/j.bbapap.2016.02.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 02/16/2016] [Accepted: 02/22/2016] [Indexed: 11/21/2022]
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19
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Hwang HJ, Dornbos P, Steidemann M, Dunivin TK, Rizzo M, LaPres JJ. Mitochondrial-targeted aryl hydrocarbon receptor and the impact of 2,3,7,8-tetrachlorodibenzo-p-dioxin on cellular respiration and the mitochondrial proteome. Toxicol Appl Pharmacol 2016; 304:121-32. [PMID: 27105554 DOI: 10.1016/j.taap.2016.04.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 04/02/2016] [Accepted: 04/08/2016] [Indexed: 11/18/2022]
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor within the Per-Arnt-Sim (PAS) domain superfamily. Exposure to the most potent AHR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is associated with various pathological effects including metabolic syndrome. While research over the last several years has demonstrated a role for oxidative stress and metabolic dysfunction in AHR-dependent TCDD-induced toxicity, the role of the mitochondria in this process has not been fully explored. Our previous research suggested that a portion of the cellular pool of AHR could be found in the mitochondria (mitoAHR). Using a protease protection assay with digitonin extraction, we have now shown that this mitoAHR is localized to the inter-membrane space (IMS) of the organelle. TCDD exposure induced a degradation of mitoAHR similar to that of cytosolic AHR. Furthermore, siRNA-mediated knockdown revealed that translocase of outer-mitochondrial membrane 20 (TOMM20) was involved in the import of AHR into the mitochondria. In addition, TCDD altered cellular respiration in an AHR-dependent manner to maintain respiratory efficiency as measured by oxygen consumption rate (OCR). Stable isotope labeling by amino acids in cell culture (SILAC) identified a battery of proteins within the mitochondrial proteome influenced by TCDD in an AHR-dependent manner. Among these, 17 proteins with fold changes≥2 are associated with various metabolic pathways, suggesting a role of mitochondrial retrograde signaling in TCDD-mediated pathologies. Collectively, these studies suggest that mitoAHR is localized to the IMS and AHR-dependent TCDD-induced toxicity, including metabolic dysfunction, wasting syndrome, and hepatic steatosis, involves mitochondrial dysfunction.
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Affiliation(s)
- Hye Jin Hwang
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States; Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI 48824, United States
| | - Peter Dornbos
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States; Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824-1319, United States
| | - Michelle Steidemann
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824-1319, United States; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, United States
| | - Taylor K Dunivin
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, United States
| | - Mike Rizzo
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824-1319, United States; Cell and Molecular Biology Graduate Program, Michigan State University, East Lansing, MI 48824, United States
| | - John J LaPres
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States; Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI 48824, United States.
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20
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Harvey WA, Jurgensen K, Pu X, Lamb CL, Cornell KA, Clark RJ, Klocke C, Mitchell KA. Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) increases human hepatic stellate cell activation. Toxicology 2016; 344-346:26-33. [PMID: 26860701 DOI: 10.1016/j.tox.2016.02.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 12/02/2015] [Accepted: 02/04/2016] [Indexed: 01/18/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a halogenated aromatic hydrocarbon that elicits toxicity through the aryl hydrocarbon receptor (AhR). In the liver, gross markers of TCDD toxicity are attributed to AhR activation in parenchymal hepatocytes. However, less is known regarding the consequences of TCDD treatment on non-parenchymal cells in the liver. Hepatic stellate cells (HSCs) are non-parenchymal cells that store vitamin A when quiescent. Upon liver injury, activated HSCs lose this storage ability and instead function in the development and maintenance of inflammation and fibrosis through the production of pro-inflammatory mediators and collagen type I. Reports that TCDD exposure disrupts hepatic retinoid homeostasis and dysregulates extracellular matrix remodeling in the liver led us to speculate that TCDD treatment may disrupt HSC activity. The human HSC line LX-2 was used to test the hypothesis that TCDD treatment directly activates HSCs. Results indicate that exposure to 10nM TCDD almost completely inhibited lipid droplet storage in LX-2 cells cultured with retinol and palmitic acid. TCDD treatment also increased LX-2 cell proliferation, expression of α-smooth muscle actin, and production of monocyte chemoattractant protein-1 (MCP-1), all of which are characteristics of activated HSCs. However, TCDD treatment had no effect on Col1a1 mRNA levels in LX-2 cells stimulated with the potent profibrogenic mediator, transforming growth factor-β. The TCDD-mediated increase in LX-2 cell proliferation, but not MCP-1 production, was abolished when phosphoinositide 3-kinase was inhibited. These results indicate that HSCs are susceptible to direct modulation by TCDD and that TCDD likely increases HSC activation through a multi-faceted mechanism.
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Affiliation(s)
- Wendy A Harvey
- Department of Biological Sciences, Boise State University, Boise, ID 83725, United States
| | - Kimberly Jurgensen
- Department of Biological Sciences, Boise State University, Boise, ID 83725, United States
| | - Xinzhu Pu
- Biomolecular Research Center, Boise State University, Boise, ID 83725, United States
| | - Cheri L Lamb
- Biomolecular Sciences Ph.D. Program, Boise State University, Boise, ID 83725, United States
| | - Kenneth A Cornell
- Biomolecular Research Center, Boise State University, Boise, ID 83725, United States; Biomolecular Sciences Ph.D. Program, Boise State University, Boise, ID 83725, United States; Department of Chemistry and Biochemistry, Boise State University, Boise, ID 83725, United States
| | - Reilly J Clark
- Department of Biological Sciences, Boise State University, Boise, ID 83725, United States
| | - Carolyn Klocke
- Department of Biological Sciences, Boise State University, Boise, ID 83725, United States
| | - Kristen A Mitchell
- Department of Biological Sciences, Boise State University, Boise, ID 83725, United States; Biomolecular Sciences Ph.D. Program, Boise State University, Boise, ID 83725, United States.
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Becker RA, Patlewicz G, Simon TW, Rowlands JC, Budinsky RA. The adverse outcome pathway for rodent liver tumor promotion by sustained activation of the aryl hydrocarbon receptor. Regul Toxicol Pharmacol 2015; 73:172-90. [PMID: 26145830 DOI: 10.1016/j.yrtph.2015.06.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 06/19/2015] [Accepted: 06/22/2015] [Indexed: 12/29/2022]
Abstract
An Adverse Outcome Pathway (AOP) represents the existing knowledge of a biological pathway leading from initial molecular interactions of a toxicant and progressing through a series of key events (KEs), culminating with an apical adverse outcome (AO) that has to be of regulatory relevance. An AOP based on the mode of action (MOA) of rodent liver tumor promotion by dioxin-like compounds (DLCs) has been developed and the weight of evidence (WoE) of key event relationships (KERs) evaluated using evolved Bradford Hill considerations. Dioxins and DLCs are potent aryl hydrocarbon receptor (AHR) ligands that cause a range of species-specific adverse outcomes. The occurrence of KEs is necessary for inducing downstream biological responses and KEs may occur at the molecular, cellular, tissue and organ levels. The common convention is that an AOP begins with the toxicant interaction with a biological response element; for this AOP, this initial event is binding of a DLC ligand to the AHR. Data from mechanistic studies, lifetime bioassays and approximately thirty initiation-promotion studies have established dioxin and DLCs as rat liver tumor promoters. Such studies clearly show that sustained AHR activation, weeks or months in duration, is necessary to induce rodent liver tumor promotion--hence, sustained AHR activation is deemed the molecular initiating event (MIE). After this MIE, subsequent KEs are 1) changes in cellular growth homeostasis likely associated with expression changes in a number of genes and observed as development of hepatic foci and decreases in apoptosis within foci; 2) extensive liver toxicity observed as the constellation of effects called toxic hepatopathy; 3) cellular proliferation and hyperplasia in several hepatic cell types. This progression of KEs culminates in the AO, the development of hepatocellular adenomas and carcinomas and cholangiolar carcinomas. A rich data set provides both qualitative and quantitative knowledge of the progression of this AOP through KEs and the KERs. Thus, the WoE for this AOP is judged to be strong. Species-specific effects of dioxins and DLCs are well known--humans are less responsive than rodents and rodent species differ in sensitivity between strains. Consequently, application of this AOP to evaluate potential human health risks must take these differences into account.
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Affiliation(s)
- Richard A Becker
- Regulatory and Technical Affairs Department, American Chemistry Council (ACC), Washington, DC 20002, USA.
| | - Grace Patlewicz
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19711, USA
| | - Ted W Simon
- Ted Simon LLC, 4184 Johnston Road, Winston, GA 30187, USA
| | - J Craig Rowlands
- The Dow Chemical Company, Toxicology & Environmental Research & Consulting, 1803 Building Washington Street, Midland, MI 48674, USA
| | - Robert A Budinsky
- The Dow Chemical Company, Toxicology & Environmental Research & Consulting, 1803 Building Washington Street, Midland, MI 48674, USA
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Jacob A, Potin S, Chapy H, Crete D, Glacial F, Ganeshamoorthy K, Couraud PO, Scherrmann JM, Declèves X. Aryl hydrocarbon receptor regulates CYP1B1 but not ABCB1 and ABCG2 in hCMEC/D3 human cerebral microvascular endothelial cells after TCDD exposure. Brain Res 2015; 1613:27-36. [DOI: 10.1016/j.brainres.2015.03.049] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 02/16/2015] [Accepted: 03/24/2015] [Indexed: 01/28/2023]
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23
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DeGroot DE, Franks DG, Higa T, Tanaka J, Hahn ME, Denison MS. Naturally occurring marine brominated indoles are aryl hydrocarbon receptor ligands/agonists. Chem Res Toxicol 2015; 28:1176-85. [PMID: 26001051 PMCID: PMC4469569 DOI: 10.1021/acs.chemrestox.5b00003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that mediates the toxic and biological effects of structurally diverse chemicals, including the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). As part of a larger effort to identify the full spectrum of chemicals that can bind to and activate the AhR, we have examined the ability of several naturally occurring marine-derived brominated indoles and brominated (methylthio)indoles (collectively referred to as brominated indoles) to bind to the AhR and stimulate AhR-dependent gene expression. Incubation of mouse, rat, and guinea pig recombinant cell lines containing a stably transfected AhR-responsive luciferase reporter gene with eight brominated indoles revealed that all compounds stimulated luciferase reporter gene activity, although some species-specific differences were observed. All compounds induced significantly more luciferase activity when incubated with cells for 4 h as compared to 24 h, demonstrating that these compounds are transient activators of the AhR signaling pathway. Three of the brominated indoles induced CYP1A1 mRNA in human HepG2 cells in vitro and Cyp1a mRNA in zebrafish embryos in vivo. The identification of the brominated indoles as direct ligands and activators/agonists of the AhR was confirmed by their ability to compete with [(3)H]TCDD for binding to the AhR and to stimulate AhR transformation and DNA binding in vitro. Taken together, these results indicate that marine-derived brominated indoles are members of a new class of naturally occurring AhR agonists.
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Affiliation(s)
- Danica E. DeGroot
- Department of Environmental Toxicology, University of California, Davis, CA USA
| | - Diana G. Franks
- Department of Biology and the Woods Hole Center for Oceans and Human Health, Woods Hole Oceanographic Institution, Woods Hole, MA USA
| | - Tatsuo Higa
- Department of Chemistry, Biology and Marine Sciences, University of the Ryukyus, Nishihara, Okinawa, JAPAN
| | - Junichi Tanaka
- Department of Chemistry, Biology and Marine Sciences, University of the Ryukyus, Nishihara, Okinawa, JAPAN
| | - Mark E. Hahn
- Department of Biology and the Woods Hole Center for Oceans and Human Health, Woods Hole Oceanographic Institution, Woods Hole, MA USA
| | - Michael S. Denison
- Department of Environmental Toxicology, University of California, Davis, CA USA
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Simon TW, Budinsky RA, Rowlands JC. A model for aryl hydrocarbon receptor-activated gene expression shows potency and efficacy changes and predicts squelching due to competition for transcription co-activators. PLoS One 2015; 10:e0127952. [PMID: 26039703 PMCID: PMC4454675 DOI: 10.1371/journal.pone.0127952] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 04/22/2015] [Indexed: 12/17/2022] Open
Abstract
A stochastic model of nuclear receptor-mediated transcription was developed based on activation of the aryl hydrocarbon receptor (AHR) by 2,3,7,8-tetrachlorodibenzodioxin (TCDD) and subsequent binding the activated AHR to xenobiotic response elements (XREs) on DNA. The model was based on effects observed in cells lines commonly used as in vitro experimental systems. Following ligand binding, the AHR moves into the cell nucleus and forms a heterodimer with the aryl hydrocarbon nuclear translocator (ARNT). In the model, a requirement for binding to DNA is that a generic coregulatory protein is subsequently bound to the AHR-ARNT dimer. Varying the amount of coregulator available within the nucleus altered both the potency and efficacy of TCDD for inducing for transcription of CYP1A1 mRNA, a commonly used marker for activation of the AHR. Lowering the amount of available cofactor slightly increased the EC50 for the transcriptional response without changing the efficacy or maximal response. Further reduction in the amount of cofactor reduced the efficacy and produced non-monotonic dose-response curves (NMDRCs) at higher ligand concentrations. The shapes of these NMDRCs were reminiscent of the phenomenon of squelching. Resource limitations for transcriptional machinery are becoming apparent in eukaryotic cells. Within single cells, nuclear receptor-mediated gene expression appears to be a stochastic process; however, intercellular communication and other aspects of tissue coordination may represent a compensatory process to maintain an organism’s ability to respond on a phenotypic level to various stimuli within an inconstant environment.
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Affiliation(s)
- Ted W. Simon
- Ted Simon LLC, Winston, GA, United States of America
- * E-mail:
| | - Robert A. Budinsky
- The Dow Chemical Company, Toxicology and Environmental Research & Consulting. Midland, MI, United States of America
| | - J. Craig Rowlands
- The Dow Chemical Company, Toxicology and Environmental Research & Consulting. Midland, MI, United States of America
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25
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Bourdon-Lacombe JA, Moffat ID, Deveau M, Husain M, Auerbach S, Krewski D, Thomas RS, Bushel PR, Williams A, Yauk CL. Technical guide for applications of gene expression profiling in human health risk assessment of environmental chemicals. Regul Toxicol Pharmacol 2015; 72:292-309. [PMID: 25944780 DOI: 10.1016/j.yrtph.2015.04.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 04/10/2015] [Accepted: 04/13/2015] [Indexed: 01/14/2023]
Abstract
Toxicogenomics promises to be an important part of future human health risk assessment of environmental chemicals. The application of gene expression profiles (e.g., for hazard identification, chemical prioritization, chemical grouping, mode of action discovery, and quantitative analysis of response) is growing in the literature, but their use in formal risk assessment by regulatory agencies is relatively infrequent. Although additional validations for specific applications are required, gene expression data can be of immediate use for increasing confidence in chemical evaluations. We believe that a primary reason for the current lack of integration is the limited practical guidance available for risk assessment specialists with limited experience in genomics. The present manuscript provides basic information on gene expression profiling, along with guidance on evaluating the quality of genomic experiments and data, and interpretation of results presented in the form of heat maps, pathway analyses and other common approaches. Moreover, potential ways to integrate information from gene expression experiments into current risk assessment are presented using published studies as examples. The primary objective of this work is to facilitate integration of gene expression data into human health risk assessments of environmental chemicals.
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Affiliation(s)
| | - Ivy D Moffat
- Water and Air Quality Bureau, Health Canada, Ottawa, ON, Canada.
| | - Michelle Deveau
- Water and Air Quality Bureau, Health Canada, Ottawa, ON, Canada
| | - Mainul Husain
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Scott Auerbach
- Biomolecular Screening Branch, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, United States
| | - Daniel Krewski
- McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, ON, Canada
| | - Russell S Thomas
- National Centre for Computational Toxicology, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States
| | - Pierre R Bushel
- Biostatistics and Computational Biology Branch, Division of Intramural Research, National Institute of Environmental Health Sciences, Research Triangle Park, NC, United States
| | - Andrew Williams
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Carole L Yauk
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
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Prokopec SD, Watson JD, Lee J, Pohjanvirta R, Boutros PC. Sex-related differences in murine hepatic transcriptional and proteomic responses to TCDD. Toxicol Appl Pharmacol 2015; 284:188-96. [PMID: 25703434 DOI: 10.1016/j.taap.2015.02.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 02/06/2015] [Accepted: 02/10/2015] [Indexed: 12/14/2022]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental contaminant that produces myriad toxicities in most mammals. In rodents alone, there is a huge divergence in the toxicological response across species, as well as among different strains within a species. But there are also significant differences between males and females animals of a single strain. These differences are inconsistent across model systems: the severity of toxicity is greater in female rats than males, while male mice and guinea pigs are more sensitive than females. Because the specific events that underlie this difference remain unclear, we characterized the hepatic transcriptional response of adult male and female C57BL/6 mice to 500μg/kg TCDD at multiple time-points. The transcriptional profile diverged significantly between the sexes. Female mice demonstrated a large number of altered transcripts as early as 6h following treatment, suggesting a large primary response. Conversely, male animals showed the greatest TCDD-mediated response 144h following exposure, potentially implicating significant secondary responses. Nr1i3 was statistically significantly induced at all time-points in the sensitive male animals. This mRNA encodes the constitutive androstane receptor (CAR), a transcription factor involved in the regulation of xenobiotic metabolism, lipid metabolism, cell cycle and apoptosis. Surprisingly though, changes at the protein level (aside from the positive control, CYP1A1) were modest, with only FMO3 showing clear induction, and no genes with sex-differences. Thus, while male and female mice show transcriptional differences in their response to TCDD, their association with TCDD-induced toxicities remains unclear.
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Affiliation(s)
- Stephenie D Prokopec
- Informatics and Bio-computing Program, Ontario Institute for Cancer Research, Toronto, Canada
| | - John D Watson
- Informatics and Bio-computing Program, Ontario Institute for Cancer Research, Toronto, Canada
| | - Jamie Lee
- Informatics and Bio-computing Program, Ontario Institute for Cancer Research, Toronto, Canada; Department of Pharmacology & Toxicology, University of Toronto, Toronto, Canada
| | - Raimo Pohjanvirta
- Laboratory of Toxicology, National Institute for Health and Welfare, Kuopio Finland; Department of Food Hygiene and Environmental Health, University of Helsinki, Helsinki, Finland
| | - Paul C Boutros
- Informatics and Bio-computing Program, Ontario Institute for Cancer Research, Toronto, Canada; Department of Pharmacology & Toxicology, University of Toronto, Toronto, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Canada.
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Kaisarevic S, Dakic V, Hrubik J, Glisic B, Lübcke-von Varel U, Pogrmic-Majkic K, Fa S, Teodorovic I, Brack W, Kovacevic R. Differential expression of CYP1A1 and CYP1A2 genes in H4IIE rat hepatoma cells exposed to TCDD and PAHs. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 39:358-368. [PMID: 25555259 DOI: 10.1016/j.etap.2014.11.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 11/04/2014] [Accepted: 11/06/2014] [Indexed: 06/04/2023]
Abstract
Rat hepatoma cells H4IIE were treated by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and polycyclic aromatic hydrocarbons (PAHs) (dibenz(a,h)anthracene, benzo(a)pyrene, benz(a)anthracene, chrysene), low-concentration mixtures of PAHs and TCDD, and environmental mixtures contaminated by PAHs and their derivatives. Expression of the gene battery comprising cytochrome P450 Cyp1a1, Cyp1a2, Cyp1b1, and glutathione-s-transferase Gsta2 and Gstp was investigated using quantitative real time polymerase chain reaction (qRT-PCR) analysis. The results revealed that TCDD induce Cyp1a1>Cyp1a2>Cyp1b1, while PAHs and PAH-containing environmental mixtures induce Cyp1a2>Cyp1a1>Cyp1b1 gene expression pattern. While low-concentration mixtures elicited a more pronounced response in comparison to single treatments, the typical gene expression patterns were not observed. In all samples, Gsta2 was predominantly expressed relative to Gstp. These findings indicate that differential Cyp1a1 and Cyp1a2 expression in the H4IIE cells might be used for detection of PAHs in highly contaminated environmental mixtures, but not in low-concentration mixtures of these compounds.
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Affiliation(s)
- Sonja Kaisarevic
- University of Novi Sad Faculty of Sciences, Department of Biology and Ecology, Trg D. Obradovica 2, 21000 Novi Sad, Serbia.
| | - Vanja Dakic
- University of Novi Sad Faculty of Sciences, Department of Biology and Ecology, Trg D. Obradovica 2, 21000 Novi Sad, Serbia
| | - Jelena Hrubik
- University of Novi Sad Faculty of Sciences, Department of Biology and Ecology, Trg D. Obradovica 2, 21000 Novi Sad, Serbia
| | - Branka Glisic
- University of Novi Sad Faculty of Sciences, Department of Biology and Ecology, Trg D. Obradovica 2, 21000 Novi Sad, Serbia
| | - Urte Lübcke-von Varel
- Helmholtz Centre for Environmental Research - UFZ, Department of Effect-Directed Analysis, Permoserstr. 15, 04318 Leipzig, Germany
| | - Kristina Pogrmic-Majkic
- University of Novi Sad Faculty of Sciences, Department of Biology and Ecology, Trg D. Obradovica 2, 21000 Novi Sad, Serbia
| | - Svetlana Fa
- University of Novi Sad Faculty of Sciences, Department of Biology and Ecology, Trg D. Obradovica 2, 21000 Novi Sad, Serbia
| | - Ivana Teodorovic
- University of Novi Sad Faculty of Sciences, Department of Biology and Ecology, Trg D. Obradovica 2, 21000 Novi Sad, Serbia
| | - Werner Brack
- Helmholtz Centre for Environmental Research - UFZ, Department of Effect-Directed Analysis, Permoserstr. 15, 04318 Leipzig, Germany
| | - Radmila Kovacevic
- University of Novi Sad Faculty of Sciences, Department of Biology and Ecology, Trg D. Obradovica 2, 21000 Novi Sad, Serbia
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28
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Girolami F, Spalenza V, Manzini L, Carletti M, Nebbia C. Constitutive expression of the AHR signaling pathway in a bovine mammary epithelial cell line and modulation by dioxin-like PCB and other AHR ligands. Toxicol Lett 2015; 232:98-105. [DOI: 10.1016/j.toxlet.2014.09.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 09/15/2014] [Accepted: 09/16/2014] [Indexed: 12/20/2022]
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29
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Kabátková M, Svobodová J, Pěnčíková K, Mohatad DS, Šmerdová L, Kozubík A, Machala M, Vondráček J. Interactive effects of inflammatory cytokine and abundant low-molecular-weight PAHs on inhibition of gap junctional intercellular communication, disruption of cell proliferation control, and the AhR-dependent transcription. Toxicol Lett 2015; 232:113-21. [DOI: 10.1016/j.toxlet.2014.09.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 09/23/2014] [Accepted: 09/26/2014] [Indexed: 12/11/2022]
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30
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Turkez H, Geyikoglu F, Yousef MI. Ameliorative effects of docosahexaenoic acid on the toxicity induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin in cultured rat hepatocytes. Toxicol Ind Health 2014; 32:1074-85. [PMID: 25187318 DOI: 10.1177/0748233714547382] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is an environmental contaminant toxicant that mediates carcinogenic effects associated with oxidative DNA damage. Docosahexaenoic acid (DHA) with antioxidant functions has many biochemical, cellular, and physiological functions for cells. The present study assessed, for the first time, the ameliorative effect of DHA in alleviating the toxicity of TCDD on primary cultured rat hepatocytes (HEPs). In vitro, isolated HEPs were incubated with TCDD (5 and 10 μM) in the presence and absence of DHA (5, 10, and 20 μM) for 48 h. The cell viability was detected by 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) release. DNA damage was analyzed by liver micronucleus assay and 8-oxo-2-deoxyguanosine (8-OH-dG) level. In addition, total antioxidant capacity (TAC) and total oxidative stress (TOS) were assessed to determine the oxidative injury in HEPs. The results of MTT and LDH assays showed that TCDD decreased cell viability but not DHA. On the basis of increasing treatment concentrations, the dioxin caused significant increases of micronucleated HEPs and 8-OH-dG as compared to control culture. TCDD also led to significant increases in TOS content. On the contrary, in cultures treated with DHA, the level of TAC was significantly increased during treatment in a concentration-dependent fashion. DHA showed therapeutic potential against TCDD-mediated cell viability and DNA damages. As conclusion, this study provides the first evidence that DHA has protective effects against TCDD toxicity on primary cultured rat hepatocytes.
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Affiliation(s)
- Hasan Turkez
- Department of Molecular Biology and Genetics, Faculty of Science, Erzurum Technical University, Erzurum, Turkey
| | - Fatime Geyikoglu
- Department of Biology, Faculty of Science, Atatürk University, Erzurum, Turkey
| | - Mokhtar I Yousef
- Department of Environmental Studies, Institute of Graduate Studies and Research, Alexandria University, Alexandria, Egypt
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31
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Angiotensin II-regulated microRNA 483-3p directly targets multiple components of the renin-angiotensin system. J Mol Cell Cardiol 2014; 75:25-39. [PMID: 24976017 DOI: 10.1016/j.yjmcc.2014.06.008] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 06/16/2014] [Accepted: 06/18/2014] [Indexed: 11/21/2022]
Abstract
Improper regulation of signaling in vascular smooth muscle cells (VSMCs) by angiotensin II (AngII) can lead to hypertension, vascular hypertrophy and atherosclerosis. The extent to which the homeostatic levels of the components of signaling networks are regulated through microRNAs (miRNA) modulated by AngII type 1 receptor (AT1R) in VSMCs is not fully understood. Whether AT1R blockers used to treat vascular disorders modulate expression of miRNAs is also not known. To report differential miRNA expression following AT1R activation by AngII, we performed microarray analysis in 23 biological and technical replicates derived from humans, rats and mice. Profiling data revealed a robust regulation of miRNA expression by AngII through AT1R, but not the AngII type 2 receptor (AT2R). The AT1R-specific blockers, losartan and candesartan antagonized >90% of AT1R-regulated miRNAs and AngII-activated AT2R did not modulate their expression. We discovered VSMC-specific modulation of 22 miRNAs by AngII, and validated AT1R-mediated regulation of 17 of those miRNAs by real-time polymerase chain reaction analysis. We selected miR-483-3p as a novel representative candidate for further study because mRNAs of multiple components of the renin-angiotensin system (RAS) were predicted to contain the target sequence for this miRNA. MiR-483-3p inhibited the expression of luciferase reporters bearing 3'-UTRs of four different RAS genes and the inhibition was reversed by antagomir-483-3p. The AT1R-regulated expression levels of angiotensinogen and angiotensin converting enzyme 1 (ACE-1) proteins in VSMCs are modulated specifically by miR-483-3p. Our study demonstrates that the AT1R-regulated miRNA expression fingerprint is conserved in VSMCs of humans and rodents. Furthermore, we identify the AT1R-regulated miR-483-3p as a potential negative regulator of steady-state levels of RAS components in VSMCs. Thus, miRNA-regulation by AngII to affect cellular signaling is a novel aspect of RAS biology, which may lead to discovery of potential candidate prognostic markers and therapeutic targets.
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32
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Solaimani P, Damoiseaux R, Hankinson O. Genome-wide RNAi high-throughput screen identifies proteins necessary for the AHR-dependent induction of CYP1A1 by 2,3,7,8-tetrachlorodibenzo-p-dioxin. Toxicol Sci 2013; 136:107-19. [PMID: 23997114 DOI: 10.1093/toxsci/kft191] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) has a plethora of physiological roles, and upon dysregulation, carcinogenesis can occur. One target gene of AHR encodes the xenobiotic and drug-metabolizing enzyme CYP1A1, which is inducible by the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) via the AHR. An siRNA library targeted against over 5600 gene candidates in the druggable genome was used to transfect mouse Hepa-1 cells, which were then treated with TCDD, and subsequently assayed for CYP1A1-dependent ethoxyresorufin-o-deethylase (EROD) activity. Following redundant siRNA activity (RSA) statistical analysis, we identified 93 hits that reduced EROD activity with a p value ≤ .005 and substantiated 39 of these as positive hits in a secondary screening using endoribonuclease-prepared siRNAs (esiRNAs). Twelve of the corresponding gene products were subsequently confirmed to be necessary for the induction of CYP1A1 messenger RNA by TCDD. None of the candidates were deficient in aryl hydrocarbon nuclear translocator expression. However 6 gene products including UBE2i, RAB40C, CRYGD, DCTN4, RBM5, and RAD50 are required for the expression of AHR as well as for induction of CYP1A1. We also found 2 gene products, ARMC8 and TCF20, to be required for the induction of CYP1A1, but our data are ambiguous as to whether they are required for the expression of AHR. In contrast, SIN3A, PDC, TMEM5, and CD9 are not required for AHR expression but are required for the induction of CYP1A1, implicating a direct role in Cyp1a1 transcription. Our methods, although applied to Cyp1a1, could be modified for identifying proteins that regulate other inducible genes.
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Affiliation(s)
- Parrisa Solaimani
- * Molecular Toxicology Interdepartmental Program, Department of Pathology and Laboratory Medicine, and the Jonsson Comprehensive Cancer Center and
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Harrill JA, Hukkanen RR, Lawson M, Martin G, Gilger B, Soldatow V, Lecluyse EL, Budinsky RA, Rowlands JC, Thomas RS. Knockout of the aryl hydrocarbon receptor results in distinct hepatic and renal phenotypes in rats and mice. Toxicol Appl Pharmacol 2013; 272:503-18. [PMID: 23859880 DOI: 10.1016/j.taap.2013.06.024] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 05/29/2013] [Accepted: 06/24/2013] [Indexed: 12/31/2022]
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor which plays a role in the development of multiple tissues and is activated by a large number of ligands, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In order to examine the roles of the AHR in both normal biological development and response to environmental chemicals, an AHR knockout (AHR-KO) rat model was created and compared with an existing AHR-KO mouse. AHR-KO rats harboring either 2-bp or 29-bp deletion mutation in exon 2 of the AHR were created on the Sprague-Dawley genetic background using zinc-finger nuclease (ZFN) technology. Rats harboring either mutation type lacked expression of AHR protein in the liver. AHR-KO rats were also insensitive to thymic involution, increased hepatic weight and the induction of AHR-responsive genes (Cyp1a1, Cyp1a2, Cyp1b1, Ahrr) following acute exposure to 25 μg/kg TCDD. AHR-KO rats had lower basal expression of transcripts for these genes and also accumulated ~30-45-fold less TCDD in the liver at 7 days post-exposure. In untreated animals, AHR-KO mice, but not AHR-KO rats, had alterations in serum analytes indicative of compromised hepatic function, patent ductus venosus of the liver and persistent hyaloid arteries in the eye. AHR-KO rats, but not AHR-KO mice, displayed pathological alterations to the urinary tract: bilateral renal dilation (hydronephrosis), secondary medullary tubular and uroepithelial degenerative changes and bilateral ureter dilation (hydroureter). The present data indicate that the AHR may play significantly different roles in tissue development and homeostasis and toxicity across rodent species.
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Key Words
- 2,3,7,8-tetracholorodibenzo-p-dioxin
- 90-kDa heat shock protein
- AHR
- AHR-KO
- AIP
- ALB
- ALP
- ALT
- ARNT
- AST
- Ahrr
- Aryl hydrocarbon receptor knockout mouse
- Aryl hydrocarbon receptor knockout rat
- BAS
- BILI
- BLO
- BUN
- CA
- CAOX
- CBC
- CHOL
- CL
- CREA
- CYP1A1
- CYP1A2
- CYP1B1
- Comparison
- DRE
- EOS
- EPI
- GGT
- GLOB
- GLUC
- HB
- HBSS
- HCT
- HSP90
- Hank's Balanced Salt Solution
- K
- KET
- Kidney
- LD(50)
- LEUC
- LYM
- Liver
- MCH
- MCHC
- MCV
- MON
- NA
- NEU
- PHOS
- PLT
- RBC
- SG
- TBA
- TBIL
- TCDD
- TP
- TPHO
- TRIG
- Tissue phenotypes
- UBIL
- UGLU
- ULEUC
- UPRO
- URBC
- UWBC
- WT
- ZFN
- alanine aminotransferase
- alkaline phosphatase
- aryl hydrocarbon receptor
- aryl hydrocarbon receptor interacting protein
- aryl hydrocarbon receptor knockout
- aryl hydrocarbon receptor nuclear translocator
- aryl hydrocarbon receptor repressor
- aspartate aminotransferase
- basophils
- blood urea nitrogen
- calcium
- calcium oxalate crystals
- chloride
- cholesterol
- complete blood count
- creatinine
- cytochrome P450, family 1, subfamily A, polypeptide 1
- cytochrome P450, family 1, subfamily A, polypeptide 2
- cytochrome P450, family 1, subfamily B, polypeptide 1
- dioxin-response element
- eosinophils
- hematocrit
- hemoglobin
- leukocytes
- lymphocytes
- mean corpuscular hemoglobin
- mean corpuscular hemoglobin concentration
- mean corpuscular volume
- median lethal dose
- monocytes
- neutrophils
- phosphorus
- platelets
- potassium
- red blood cells
- serum albumin
- serum globulin
- serum glucose
- sodium
- total bile acid
- total bilirubin
- total serum protein
- total white blood cells
- triglycerides
- triple phosphate crystals
- urine bilinogen
- urine bilirubin
- urine epithelial cells
- urine glucose
- urine ketones
- urine leukocytes
- urine occult blood
- urine protein
- urine red blood cells
- urine specific gravity
- wild-type
- zinc finger nuclease
- γ-glutamyl transpeptidase
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Affiliation(s)
- Joshua A Harrill
- The Hamner Institute for Health Sciences, Institute for Chemical Safety Sciences, RTP, NC 27709, USA
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Aly HAA, El-Shitany NA, El-Beshbishy HA, Ashour OM. Ameliorative effect of lycopene against 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced rat liver microsomal toxicity. Toxicol Ind Health 2013; 31:938-50. [DOI: 10.1177/0748233713475504] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The objective of the current study was to investigate the potential oxidative damage of 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) in hepatic microsomal fractions in vitro and to further elucidate the potential modulatory effect of lycopene. Rat liver microsomes were divided into four groups. Group I served as a control and is incubated with vehicle (toluene). Groups II and IV were incubated with 20 µM lycopene for 1 h before further incubating; groups III and IV with 15 nM of TCDD for further 1 h. Hydrogen peroxide (H2O2) production, lipid peroxidation (LPO), protein carbonyl content and activities of uridine 5′-diphospho-glucuronyltransferase (UDPGT) and P450 were significantly increased. Moreover, the activity of antioxidant enzymes superoxide dismutase, glutathione peroxidase, catalse, glutathione- S-transferase and glutathione reductase as well as the microsomal thiol content were significantly decreased. Incubation with lycopene (group IV) maintained near normal activities of the enzymes, normalized thiol and carbonyl content and significantly reduced LPO and H2O2 production. In conclusion, the findings of the study indicate that TCDD induces a significant oxidative stress in liver microsomes as manifested by increased LPO, H2O2 production, protein carbonyl content and activities of UDPGT and P450 and decreased antioxidant enzymes activities and thiol content. By the reversal of biochemical and oxidative markers toward normalcy, the protective role of lycopene is illuminated in rat liver microsomal toxicity.
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Affiliation(s)
- Hamdy AA Aly
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Al-Azhar University, Nasr City, Cairo, Egypt
| | - Nagla A El-Shitany
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Pharmacology and Toxicology, College of Pharmacy, Tanta University, Tanta, Egypt
| | - Hesham A El-Beshbishy
- Department of Biochemistry, Faculty of Pharmacy, Al-Azhar University, Nasr City, Cairo, Egypt
- Department of Medical Laboratories Technology, Faculty of Applied Medical Sciences, Taibah University, Al-Madinah Al-Munawwarrah, Saudi Arabia
| | - Osama M Ashour
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia
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Desaulniers D, Xiao GH, Cummings-Lorbetskie C. Effects of lactational and/or in utero exposure to environmental contaminants on the glucocorticoid stress-response and DNA methylation of the glucocorticoid receptor promoter in male rats. Toxicology 2013; 308:20-33. [PMID: 23537661 DOI: 10.1016/j.tox.2013.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 03/06/2013] [Accepted: 03/15/2013] [Indexed: 10/27/2022]
Abstract
Perinatal events can reprogram the hypothalamo-pituitary-adrenal axis for the entire lifespan leading to abnormal glucocorticoid stress-response (GSR) in adulthood: a phenomenon reported to be mediated by changes in DNA methylation of the glucocorticoid receptor (GR) gene promoter. We examined whether in utero and/or lactational exposure to mixtures of environmental contaminants can also induce abnormal GSR during adulthood. The experiment included nine treatment groups. From gestation day (GD) 0 until postnatal day (PND) 20, dams were fed daily with a cookie laced with corn oil (control) or a chemical mixture (M) [polychlorinated biphenyls (PCBs), organochlorine pesticides, and methylmercury] at 0.5 or 1.0mg/kg/day (0.5M, and M). At birth, some control (C) and M litters were cross-fostered to create four groups with the following in utero/postnatal exposure: C/C, M/C, C/M, M/M. Other dams received 1.8ng/kg/day of a mixture of aryl hydrocarbon receptor (AhR) agonists (non-ortho PCBs, PC-dibenzodioxins and PC-dibenzofurans) without or with 0.5M (0.5MAhR). In adult male offspring the abundance of GR in treated groups was not different from the control, but the AhR and M groups were significantly different from each other with opposite effects in the hippocampus and liver. There was no change in DNA methylation of the GR promoter (exon-17 and -110). Abnormal GSRs were detected in the AhR, 0.5MAhR, CM, and MM groups. The literature associates abnormal GSR with metabolic and mental health impairments, thus these results support further investigation of the influence of developmental exposure to environmental contaminants and predisposition to stress-induced diseases.
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Affiliation(s)
- D Desaulniers
- Health Canada, Healthy Environments and Consumer Safety Branch, Hazard Identification Division, AL: 0803D Tunney's Pasture, Ottawa, Ontario K1A 0K9, Canada.
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Forgacs AL, Dere E, Angrish MM, Zacharewski TR. Comparative analysis of temporal and dose-dependent TCDD-elicited gene expression in human, mouse, and rat primary hepatocytes. Toxicol Sci 2013; 133:54-66. [PMID: 23418086 DOI: 10.1093/toxsci/kft028] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)-elicited time- and dose-dependent differential gene expression was compared in human, mouse, and rat primary hepatocytes. Comprehensive time course (10 nM TCDD or dimethyl sulfoxide vehicle control for 1, 2, 4, 8, 12, 24, and 48h) studies identified 495, 2305, and 711 differentially expressed orthologous genes in human, mouse, and rat hepatocytes, respectively. However, only 16 orthologs were differentially expressed across all three species, with the majority of orthologs exhibiting species-specific expression (399 human, 2097 mouse, and 533 rat), consistent with species-specific expression reported in other in vitro and in vivo comparative studies. TCDD also elicited the dose-dependent induction of 397 human, 100 mouse, and 443 rat genes at 12h and 615 human, 426 mouse, and 314 rat genes at 24h. Comparable EC50 values were obtained for AhR battery genes including Cyp1a1 (0.1 nM human, 0.05 nM mouse, 0.08 nM rat at 24h) and Tiparp (0.97 nM human, 0.63 nM mouse, 0.14 nM rat at 12h). Overrepresented functions and pathways included amino acid metabolism in humans, immune response in mice, and energy homeostasis in rats. Differentially expressed genes functionally associated with lipid transport, processing, and metabolism were overrepresented in all three species but exhibited species-specific expression consistent with the induction of hepatic steatosis in mice but not in rats following a single oral gavage of TCDD. Furthermore, human primary hepatocytes showed lipid accumulation following 48h of treatment with TCDD, suggesting that AhR-mediated steatosis in mice more closely resembles human hepatic fat accumulation compared with that in rats. Collectively, these results suggest that species-specific gene expression profiles mediate the species-specific effects of TCDD despite the conservation of the AhR and its signaling mechanism.
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Affiliation(s)
- Agnes L Forgacs
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
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Nault R, Kim S, Zacharewski TR. Comparison of TCDD-elicited genome-wide hepatic gene expression in Sprague-Dawley rats and C57BL/6 mice. Toxicol Appl Pharmacol 2012; 267:184-91. [PMID: 23238561 DOI: 10.1016/j.taap.2012.11.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 11/16/2012] [Accepted: 11/19/2012] [Indexed: 12/16/2022]
Abstract
Although the structure and function of the AhR are conserved, emerging evidence suggests that downstream effects are species-specific. In this study, rat hepatic gene expression data from the DrugMatrix database (National Toxicology Program) were compared to mouse hepatic whole-genome gene expression data following treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). For the DrugMatrix study, male Sprague-Dawley rats were gavaged daily with 20μg/kg TCDD for 1, 3 and 5days, while female C57BL/6 ovariectomized mice were examined 1, 3 and 7days after a single oral gavage of 30μg/kg TCDD. A total of 649 rat and 1386 mouse genes (|fold change|≥1.5, P1(t)≥0.99) were differentially expressed following treatment. HomoloGene identified 11,708 orthologs represented across the rat Affymetrix 230 2.0 GeneChip (12,310 total orthologs), and the mouse 4×44K v.1 Agilent oligonucleotide array (17,578 total orthologs). Comparative analysis found 563 and 922 orthologs differentially expressed in response to TCDD in the rat and mouse, respectively, with 70 responses associated with immune function and lipid metabolism in common to both. Moreover, QRTPCR analysis of Ceacam1, showed divergent expression (induced in rat; repressed in mouse) functionally consistent with TCDD-elicited hepatic steatosis in the mouse but not the rat. Functional analysis identified orthologs involved in nucleotide binding and acetyltransferase activity in rat, while mouse-specific responses were associated with steroid, phospholipid, fatty acid, and carbohydrate metabolism. These results provide further evidence that TCDD elicits species-specific regulation of distinct gene networks, and outlines considerations for future comparisons of publicly available microarray datasets.
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Affiliation(s)
- Rance Nault
- Department of Biochemistry and Molecular Biology, Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, USA
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Faust D, Vondráček J, Krčmář P, Šmerdová L, Procházková J, Hrubá E, Hulinková P, Kaina B, Dietrich C, Machala M. AhR-mediated changes in global gene expression in rat liver progenitor cells. Arch Toxicol 2012. [DOI: 10.1007/s00204-012-0979-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Phark S, Park SY, Choi S, Zheng Z, Cho E, Lee M, Lim JY, Seo JB, Won NH, Jung WW, Sul D. Toxicological biomarkers of 2,3,4,7,8-pentachlorodibenzofuran in proteins secreted by HepG2 cells. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:656-66. [DOI: 10.1016/j.bbapap.2012.01.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 01/20/2012] [Accepted: 01/22/2012] [Indexed: 01/08/2023]
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Abstract
Personalized medicine is based on intraspecies differences. It is axiomatic that small differences in genetic make-up can result in dramatic differences in response to drugs or disease. To express this in more general terms: in any given complex system, small changes in initial conditions can result in dramatically different outcomes. Despite human variability and intraspecies variation in other species, nonhuman species are still the primary model for ascertaining data for humans. We call this practice into question and conclude that human-based research should be the primary means for obtaining data about human diseases and responses to drugs.
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Affiliation(s)
| | - Andre Menache
- Americans For Medical Advancement, 2251 Refugio Rd, Goleta, CA 93117, USA
| | - Mark J Rice
- Department of Anesthesiology, University of Florida College of Medicine, PO Box 100254, Gainesville, FL 32610-0254, USA
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Forgacs AL, Kent MN, Makley MK, Mets B, DelRaso N, Jahns GL, Burgoon LD, Zacharewski TR, Reo NV. Comparative metabolomic and genomic analyses of TCDD-elicited metabolic disruption in mouse and rat liver. Toxicol Sci 2011; 125:41-55. [PMID: 21964420 DOI: 10.1093/toxsci/kfr262] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) elicits a broad spectrum of species-specific effects that have not yet been fully characterized. This study compares the temporal effects of TCDD on hepatic aqueous and lipid metabolite extracts from immature ovariectomized C57BL/6 mice and Sprague-Dawley rats using gas chromatography-mass spectrometry and nuclear magnetic resonance-based metabolomic approaches and integrates published gene expression data to identify species-specific pathways affected by treatment. TCDD elicited metabolite and gene expression changes associated with lipid metabolism and transport, choline metabolism, bile acid metabolism, glycolysis, and glycerophospholipid metabolism. Lipid metabolism is altered in mice resulting in increased hepatic triacylglycerol as well as mono- and polyunsaturated fatty acid (FA) levels. Mouse-specific changes included the induction of CD36 and other cell surface receptors as well as lipases- and FA-binding proteins consistent with hepatic triglyceride and FA accumulation. In contrast, there was minimal hepatic fat accumulation in rats and decreased CD36 expression. However, choline metabolism was altered in rats, as indicated by decreases in betaine and increases in phosphocholine with the concomitant induction of betaine-homocysteine methyltransferase and choline kinase gene expression. Results from these studies show that aryl hydrocarbon receptor-mediated differential gene expression could be linked to metabolite changes and species-specific alterations of biochemical pathways.
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Affiliation(s)
- Agnes L Forgacs
- Department of Biochemistry and Molecular Biology, Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824, USA
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Turkez H, Geyikoglu F, Mokhtar YI, Togar B. Eicosapentaenoic acid protects against 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced hepatic toxicity in cultured rat hepatocytes. Cytotechnology 2011; 64:15-25. [PMID: 21938470 DOI: 10.1007/s10616-011-9386-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 07/23/2011] [Indexed: 12/20/2022] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent and ubiquitous environmental contaminant. The health impact of TCDD exposure is of great concern to the general public. Recent reports have implied that eicosapentaenoic acid (EPA) might be a potential chemopreventive agent and influence hepatotoxicity. The aim of the current study was to explore the effectiveness of EPA in alleviating the toxicity of TCDD on primary cultured rat hepatocytes. EPA (5, 10 and 20 μM) was added to cultures alone or simultaneously with TCDD (5 and 10 μM). Rat hepatocytes were treated with TCDD and EPA for 48 h, and then cytotoxicity was detected by [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] (MTT) assay and lactate dehydrogenase (LDH) release, while total antioxidant capacity (TAC) and total oxidative stress (TOS) levels were determined to evaluate the oxidative injury. The DNA damage was also analyzed by liver micronucleus assay (LMN) and 8-oxo-2-deoxyguanosine (8-OH-dG). The results of MTT and LDH assays showed that TCDD but not EPA decreased cell viability. TCDD also increased TOS level and significantly decreased TAC level in rat hepatocytes in a clear dose dependent manner. On the basis of increasing doses, the dioxin caused significant increases of micronucleated hepatocytes (MNHEPs) and 8-OH-dG as compared to control culture. Whereas, in cultures treated with EPA alone, TOS level did not change and the level of TAC significantly increased. The presence of EPA with TCDD minimized the toxic effects of the dioxin on primary hepatocytes cultures. Noteworthy, EPA has a protective effect against TCDD-mediated DNA damages.
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Affiliation(s)
- Hasan Turkez
- Department of Biology, Faculty of Sciences, Atatürk University, 25240, Erzurum, Turkey
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Denison MS, Soshilov AA, He G, DeGroot DE, Zhao B. Exactly the same but different: promiscuity and diversity in the molecular mechanisms of action of the aryl hydrocarbon (dioxin) receptor. Toxicol Sci 2011; 124:1-22. [PMID: 21908767 DOI: 10.1093/toxsci/kfr218] [Citation(s) in RCA: 562] [Impact Index Per Article: 43.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Ah receptor (AhR) is a ligand-dependent transcription factor that mediates a wide range of biological and toxicological effects that result from exposure to a structurally diverse variety of synthetic and naturally occurring chemicals. Although the overall mechanism of action of the AhR has been extensively studied and involves a classical nuclear receptor mechanism of action (i.e., ligand-dependent nuclear localization, protein heterodimerization, binding of liganded receptor as a protein complex to its specific DNA recognition sequence and activation of gene expression), details of the exact molecular events that result in most AhR-dependent biochemical, physiological, and toxicological effects are generally lacking. Ongoing research efforts continue to describe an ever-expanding list of ligand-, species-, and tissue-specific spectrum of AhR-dependent biological and toxicological effects that seemingly add even more complexity to the mechanism. However, at the same time, these studies are also identifying and characterizing new pathways and molecular mechanisms by which the AhR exerts its actions and plays key modulatory roles in both endogenous developmental and physiological pathways and response to exogenous chemicals. Here we provide an overview of the classical and nonclassical mechanisms that can contribute to the differential sensitivity and diversity in responses observed in humans and other species following ligand-dependent activation of the AhR signal transduction pathway.
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Affiliation(s)
- Michael S Denison
- Department of Environmental Toxicology, University of California, Davis, California 95616, USA.
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Kopec AK, D'Souza ML, Mets BD, Burgoon LD, Reese SE, Archer KJ, Potter D, Tashiro C, Sharratt B, Harkema JR, Zacharewski TR. Non-additive hepatic gene expression elicited by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153) co-treatment in C57BL/6 mice. Toxicol Appl Pharmacol 2011; 256:154-67. [PMID: 21851831 DOI: 10.1016/j.taap.2011.08.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 07/22/2011] [Accepted: 08/01/2011] [Indexed: 11/18/2022]
Abstract
Interactions between environmental contaminants can lead to non-additive effects that may affect the toxicity and risk assessment of a mixture. Comprehensive time course and dose-response studies with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), non-dioxin-like 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153) and their mixture were performed in immature, ovariectomized C57BL/6 mice. Mice were gavaged once with 30 μg/kg TCDD, 300 mg/kg PCB153, a mixture of 30 μg/kg TCDD with 300 mg/kg PCB153 (MIX) or sesame oil vehicle for 4,12, 24,72 or 168 h. In the 24h dose-response study, animals were gavaged with TCDD (0.3,1, 3, 6, 10, 15, 30, 45 μg/kg), PCB153 (3,10, 30, 60, 100, 150, 300, 450 mg/kg), MIX (0.3+3, 1+10, 3+30, 6+60, 10+100, 15+150, 30+300, 45 μg/kg TCDD+450 mg/kg PCB153, respectively) or vehicle. All three treatments significantly increased relative liver weights (RLW), with MIX eliciting significantly greater increases compared to TCDD and PCB153 alone. Histologically, MIX induced hepatocellular hypertrophy, vacuolization, inflammation, hyperplasia and necrosis, a combination of TCDD and PCB153 responses. Complementary lipid analyses identified significant increases in hepatic triglycerides in MIX and TCDD samples, while PCB153 had no effect on lipids. Hepatic PCB153 levels were also significantly increased with TCDD co-treatment. Microarray analysis identified 167 TCDD, 185 PCB153 and 388 MIX unique differentially expressed genes. Statistical modeling of quantitative real-time PCR analysis of Pla2g12a, Serpinb6a, Nqo1, Srxn1, and Dysf verified non-additive expression following MIX treatment compared to TCDD and PCB153 alone. In summary, TCDD and PCB153 co-treatment elicited specific non-additive gene expression effects that are consistent with RLW increases, histopathology, and hepatic lipid accumulation.
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Affiliation(s)
- Anna K Kopec
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824-1319, USA
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