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Pecori Giraldi F, Ferraù F, Ragonese M, Cannavò S. Endocrine disruptors, aryl hydrocarbon receptor and cortisol secretion. J Endocrinol Invest 2024:10.1007/s40618-024-02371-w. [PMID: 38637430 DOI: 10.1007/s40618-024-02371-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 03/29/2024] [Indexed: 04/20/2024]
Abstract
PURPOSE Endocrine disruptors exert a plethora of effects in endocrine tissues, from altered function to carcinogenesis. Given its lipophilic nature, the adrenal cortex represents an ideal target for endocrine disruptors and thus, possibly, xenobiotic-induced adrenocortical dysfunction. However, there is no clear understanding of the effect of endocrine disruptors on adrenal steroidogenesis, in particular as regards the aryl hydrocarbon receptor (AHR) pathway, one of the key mediators. METHODS The present review recapitulates available evidence on the effects of AHR ligands on adrenal steroidogenesis, with focus on cortisol secretion. RESULTS Short-term exposure to AHR ligands most often induced a stress-like corticosteroid response followed by decreased responsiveness to stressors with long-term exposure. This was observed in several experimental models across species as well as in animals and humans in real-life settings. Prenatal exposure led to different effects according to sex of the offspring, as observed in murine models and in children from mothers in several countries. In vitro findings proved highly dependent on the experimental setting, with reduced cortisol response and steroidogenic enzyme synthesis mostly observed in fish and increased cortisol synthesis and secretion observed in murine and human adrenal cell lines. Of note, no AHR-binding element was detected in steroidogenic enzyme promoters, suggesting the involvement of additional factors. CONCLUSION Our review provides evidence for the impact of AHR ligands on adrenocortical function and indicates further avenues of research to better clarify its effects.
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Affiliation(s)
- F Pecori Giraldi
- Department of Clinical Sciences and Community Health, University of Milan, Via Commenda 19, Milan, Italy.
| | - F Ferraù
- Department of Human Pathology of Adulthood and Childhood "Gaetano Barresi,", University of Messina, Messina, Italy
| | - M Ragonese
- Department of Human Pathology of Adulthood and Childhood "Gaetano Barresi,", University of Messina, Messina, Italy
| | - S Cannavò
- Department of Human Pathology of Adulthood and Childhood "Gaetano Barresi,", University of Messina, Messina, Italy
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2
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Ke T, Tinkov AA, Skalny AV, Santamaria A, Rocha JBT, Bowman AB, Chen W, Aschner M. Epigenetics and Methylmercury-Induced Neurotoxicity, Evidence from Experimental Studies. TOXICS 2023; 11:toxics11010072. [PMID: 36668798 PMCID: PMC9860901 DOI: 10.3390/toxics11010072] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/08/2023] [Accepted: 01/10/2023] [Indexed: 05/14/2023]
Abstract
MeHg is an environmental neurotoxin that can adversely affect the development of the nervous system. The molecular integrity of chromatin in the nucleus is an important target of MeHg. Low levels of MeHg trigger epigenetic mechanisms that may be involved in long-lasting and transgenerational neurotoxicity after exposure. Emerging evidence has shown that these mechanisms include histone modification, siRNA, and DNA methylation. The MeHg-induced inhibition of neurodifferentiation and neurogenesis are mechanistically associated with epigenetic alterations in critical genes, such as neurotrophin brain-derived neurotrophic factor (BDNF). Further, MeHg exposure has been shown to alter the activity and/or expression of the upstream regulators of chromatin structure, including histone deacetylases (HDACs) and DNA methyltransferase (DNMTs), which may trigger permanent alterations in histone modifications and DNA methylation. MeHg-exposure also alters several species of miRNA that are associated with neurodevelopment. Genetic studies in the C. elegans model of MeHg-induced toxicity proposes a potential interplay between exogenous RNAi and antioxidant defense. In this review, we discuss the molecular basis for MeHg exposure-induced alterations in chromatin structure and the roles of histone modifications, siRNA, and DNA methylation in MeHg-induced neurotoxic effects.
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Affiliation(s)
- Tao Ke
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Correspondence: (T.K.); (M.A.)
| | - Alexey A. Tinkov
- World-Class Research Center “Digital Biodesign and Personalized Healthcare”, IM Sechenov First Moscow State Medical University (Sechenov University), 119435 Moscow, Russia
- Laboratory of Ecobiomonitoring and Quality Control, Yaroslavl State University, 150003 Yaroslavl, Russia
- Department of Medical Elementology, RUDN University, 117198 Moscow, Russia
| | - Anatoly V. Skalny
- World-Class Research Center “Digital Biodesign and Personalized Healthcare”, IM Sechenov First Moscow State Medical University (Sechenov University), 119435 Moscow, Russia
- Department of Medical Elementology, RUDN University, 117198 Moscow, Russia
| | - Abel Santamaria
- Laboratorio de Aminoácidos Excitadores/Laboratorio de Neurofarmacología Molecular y Nanotecnología, Instituto Nacional de Neurología y Neurocirugía, Mexico City 14269, Mexico
| | - Joao B. T. Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria 97105-900, RS, Brazil
| | - Aaron B. Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Wen Chen
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Correspondence: (T.K.); (M.A.)
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Kimura E, Suzuki G, Uramaru N, Endo T, Maekawa F. Behavioral impairments in infant and adult mouse offspring exposed to 2,3,7,8-tetrabromodibenzofuran in utero and via lactation. ENVIRONMENT INTERNATIONAL 2020; 142:105833. [PMID: 32559560 DOI: 10.1016/j.envint.2020.105833] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 04/19/2020] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
Polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/DFs) have been unintentionally produced and emitted from the lifecycle of products containing brominated flame retardants, such as polybrominated diphenyl ether, which is suspected to cause developmental neurotoxicity (DNT). Although it is plausible that PBDD/DFs can also induce DNT, information regarding their neurotoxic potential is currently limited. Hence, in the present study, we examined the effects of in utero and lactational exposure to brominated dibenzofurans on infant and adult offspring behavior to understand the mechanism of PBDD/DFs toxicity and detect effective behavioral endpoints in DNT assessment. We analyzed the behavior of mouse offspring born to dams administered 2,3,7,8-tetrabromodibenzofuran (2,3,7,8-TeBDF; dose of 0, 9, or 45 μg/kg) or 2,3,8-tribromodibenzofuran (2,3,8-TrBDF; dose of 0, 75.6, or 378 μg/kg) on gestational day 12.5. In mouse offspring born to dams exposed to 2,3,7,8-TeBDF, the exploratory behavior in a novel environment in adulthood and ultrasonic vocalization (USV) during infancy were significantly reduced. Additionally, AhR-target genes, such as Cyp1a1, were induced in the liver of 2,3,7,8-TeBDF-exposed offspring in a dose-dependent manner. Conversely, no significant changes in the infant and adult behaviors and expression level of AhR-target genes were observed in the 2,3,8-TrBDF-exposed offspring. These results suggest that 2,3,7,8-TeBDF can induce DNT and that the analysis of exploratory behavior in a novel environment and USV may be useful endpoints to assess DNT of dioxin-related substances.
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Affiliation(s)
- Eiki Kimura
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan; Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083, Japan
| | - Go Suzuki
- Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan
| | - Naoto Uramaru
- Nihon Pharmaceutical University, 10281 Komuro Ina-machi, Kitaadachi-gun, Saitama 362-0806, Japan
| | - Toshihiro Endo
- Phenovance Research & Technology, 5-4-19-302A, Kashiwanoha, Kashiwa, Chiba 277-0882, Japan
| | - Fumihiko Maekawa
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan.
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Sex-specific effects of developmental exposure to polychlorinated biphenyls on neuroimmune and dopaminergic endpoints in adolescent rats. Neurotoxicol Teratol 2020; 79:106880. [PMID: 32259577 DOI: 10.1016/j.ntt.2020.106880] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/17/2020] [Accepted: 03/24/2020] [Indexed: 12/22/2022]
Abstract
Exposure to environmental contaminants early in life can have long lasting consequences for physiological function. Polychlorinated biphenyls (PCBs) are a group of ubiquitous contaminants that perturb endocrine signaling and have been associated with altered immune function in children. In this study, we examined the effects of developmental exposure to PCBs on neuroimmune responses to an inflammatory challenge during adolescence. Sprague Dawley rat dams were exposed to a PCB mixture (Aroclor 1242, 1248, 1254, 1:1:1, 20 μg/kg/day) or oil control throughout pregnancy, and adolescent male and female offspring were injected with lipopolysaccharide (LPS, 50 μg/kg, ip) or saline control prior to euthanasia. Gene expression profiling was conducted in the hypothalamus, prefrontal cortex, striatum, and midbrain. In the hypothalamus, PCBs increased expression of genes involved in neuroimmune function, including those within the nuclear factor kappa b (NF-κB) complex, independent of LPS challenge. PCB exposure also increased expression of receptors for dopamine, serotonin, and estrogen in this region. In contrast, in the prefrontal cortex, PCB exposure blunted or induced irregular neuroimmune gene expression responses to LPS challenge. Moreover, neither PCB nor LPS exposure altered expression of neurotransmitter receptors throughout the mesocorticolimbic circuit. Almost all effects were present in males but not females, in agreement with the idea that male neuroimmune cells are more sensitive to perturbation and emphasizing the importance of studying both male and female subjects. Given that altered neuroimmune signaling has been implicated in mental health and substance abuse disorders that often begin during adolescence, these results highlight neuroimmune processes as another mechanism by which early life PCBs can alter brain function later in life.
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5
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Desaulniers D, Khan N, Cummings-Lorbetskie C, Leingartner K, Xiao GH, Williams A, Yauk CL. Effects of cross-fostering and developmental exposure to mixtures of environmental contaminants on hepatic gene expression in prepubertal 21 days old and adult male Sprague-Dawley rats. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2019; 82:1-27. [PMID: 30744511 DOI: 10.1080/15287394.2018.1542360] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 10/24/2018] [Accepted: 10/26/2018] [Indexed: 06/09/2023]
Abstract
The notion that adverse health effects produced by exposure to environmental contaminants (EC) may be modulated by the presence of non-chemical stressors is gaining attention. Previously, our lab demonstrated that cross-fostering (adoption of a litter at birth) acted as a non-chemical stressor that amplified the influence of developmental exposure to EC on the glucocorticoid stress-response in adult rats. Using liver from the same rats, the aim of the current study was to investigate whether cross-fostering might also modulate EC-induced alterations in hepatic gene expression profiles. During pregnancy and nursing, Sprague-Dawley dams were fed cookies laced with corn oil (control, C) or a chemical mixture (M) composed of polychlorinated biphenyls (PCB), organochlorine pesticides (OCP), and methylmercury (MeHg), at 1 mg/kg/day. This mixture simulated the contaminant profile reported in maternal human blood. At birth, some control and M treated litters were cross-fostered to form two additional groups with different biological/nursing mothers (CC and MM). The hepatic transcriptome was analyzed by DNA microarray in male offspring at postnatal days 21 and 78-86. Mixture exposure altered the expression of detoxification and energy metabolism genes in both age groups, but with different sets of genes affected at day 21 and 78-86. Cross-fostering modulated the effects of M on gene expression pattern (MM vs M), as well as expression of energy metabolism genes between control groups (CC vs C). In conclusion, while describing short and long-term effects of developmental exposure to EC on hepatic transcriptomes, these cross-fostering results further support the consideration of non-chemical stressors in EC risk assessments.
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Affiliation(s)
- D Desaulniers
- a Health Canada, Healthy Environments and Consumer Safety Branch , Environmental Health Science and Research Bureau , Ottawa , Ontario , Canada
| | - N Khan
- a Health Canada, Healthy Environments and Consumer Safety Branch , Environmental Health Science and Research Bureau , Ottawa , Ontario , Canada
| | - C Cummings-Lorbetskie
- a Health Canada, Healthy Environments and Consumer Safety Branch , Environmental Health Science and Research Bureau , Ottawa , Ontario , Canada
| | - K Leingartner
- a Health Canada, Healthy Environments and Consumer Safety Branch , Environmental Health Science and Research Bureau , Ottawa , Ontario , Canada
| | - G-H Xiao
- a Health Canada, Healthy Environments and Consumer Safety Branch , Environmental Health Science and Research Bureau , Ottawa , Ontario , Canada
| | - A Williams
- a Health Canada, Healthy Environments and Consumer Safety Branch , Environmental Health Science and Research Bureau , Ottawa , Ontario , Canada
| | - C L Yauk
- a Health Canada, Healthy Environments and Consumer Safety Branch , Environmental Health Science and Research Bureau , Ottawa , Ontario , Canada
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6
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Bell MR, Dryden A, Will R, Gore AC. Sex differences in effects of gestational polychlorinated biphenyl exposure on hypothalamic neuroimmune and neuromodulator systems in neonatal rats. Toxicol Appl Pharmacol 2018; 353:55-66. [PMID: 29879404 DOI: 10.1016/j.taap.2018.06.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 05/15/2018] [Accepted: 06/01/2018] [Indexed: 01/05/2023]
Abstract
Polychlorinated biphenyls (PCBs) are ubiquitous in the environment and exposure to them is associated with immune, endocrine and neural dysfunction. Effects of PCBs on inflammation and immunity are best described in spleen and blood, with fewer studies on neural tissues. This is an important gap in knowledge, as molecules typically associated with neuroinflammation also serve neuromodulatory roles and interact with hormones in normal brain development. The current study used Sprague-Dawley rats to assess whether gestational PCB exposure altered hypothalamic gene expression and serum cytokine concentration in neonatal animals given an immune challenge. Dams were fed wafers containing a mixture of PCBs at an environmentally relevant dose and composition (20 μg/kg, 1:1:1 Aroclor 1242:1248:1254) or oil vehicle control throughout their pregnancy. One day old male and female offspring were treated with an inflammatory challenge (lipopolysaccharide, LPS, 50 μg/kg, sc) or saline vehicle control approximately 3.5 h prior to tissue collection. Across both basal and activated inflammatory states, PCB exposure caused greater expression of a subset of inflammatory genes in the hypothalamus and lower expression of genes involved in dopamine, serotonin, and opioid systems compared to oil controls. PCB exposure also altered reactions to inflammatory challenge: it reversed the normal decrease in Esr2 hypothalamic expression and induced an abnormal increase in IL-1b and IL-6 serum concentration in response to LPS. Many of these effects were sex specific. Given the potential long-term consequences of neuroimmune disruption, our findings demonstrate the need for further research.
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Affiliation(s)
- Margaret R Bell
- Department of Biological Sciences and Department of Health Sciences, DePaul University, Chicago, IL 60614, United States.
| | - Ariel Dryden
- Franklin College, Franklin, IN 46131, United States.
| | - Ryan Will
- Department of Psychology, The University of Texas at Austin, Austin, TX 78712, United States
| | - Andrea C Gore
- Division of Pharmacology and Toxicology, College of Pharmacy, Institute for Cellular and Molecular Biology, and Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712, United States.
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Sobolewski M, Conrad K, Marvin E, Allen JL, Cory-Slechta DA. Endocrine active metals, prenatal stress and enhanced neurobehavioral disruption. Horm Behav 2018; 101:36-49. [PMID: 29355495 PMCID: PMC5970043 DOI: 10.1016/j.yhbeh.2018.01.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 01/05/2018] [Accepted: 01/14/2018] [Indexed: 11/24/2022]
Abstract
Metals, including lead (Pb), methylmercury (MeHg) and arsenic (As), are long-known developmental neurotoxicants. More recently, environmental context has been recognized to modulate metals toxicity, including nutritional state and stress exposure. Modulation of metal toxicity by stress exposure can occur through shared targeting of endocrine systems, such as the hypothalamic-pituitary-adrenal axis (HPA). Our previous rodent research has identified that prenatal stress (PS) modulates neurotoxicity of two endocrine active metals (EAMs), Pb and MeHg, by altering HPA and CNS systems disrupting behavior. Here, we review this research and further test the hypothesis that prenatal stress modulates metals neurotoxicity by expanding to test the effect of developmental As ± PS exposure. Serum corticosterone and behavior was assessed in offspring of dams exposed to As ± PS. PS increased female offspring serum corticosterone at birth, while developmental As exposure decreased adult serum corticosterone in both sexes. As + PS induced reductions in locomotor activity in females and reduced response rates on a Fixed Interval schedule of reinforcement in males, with the latter suggesting unique learning deficits only in the combined exposure. As-exposed males showed increased time in the open arms of an elevated plus maze and decreased novel object recognition whereas females did not. These data further confirm the hypothesis that combined exposure to chemical (EAMs) and non-chemical (PS) stressors results in enhanced neurobehavioral toxicity. Given that humans are exposed to multiple environmental risk factors that alter endocrine function in development, such models are critical for risk assessment and public health protection, particularly for children.
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Affiliation(s)
- Marissa Sobolewski
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States. marissa:
| | - Katherine Conrad
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States
| | - Elena Marvin
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States
| | - Joshua L Allen
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States
| | - Deborah A Cory-Slechta
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States
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8
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Aluru N, Karchner SI, Krick KS, Zhu W, Liu J. Role of DNA methylation in altered gene expression patterns in adult zebrafish ( Danio rerio) exposed to 3, 3', 4, 4', 5-pentachlorobiphenyl (PCB 126). ENVIRONMENTAL EPIGENETICS 2018; 4:dvy005. [PMID: 29686887 PMCID: PMC5905506 DOI: 10.1093/eep/dvy005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 02/09/2018] [Accepted: 03/08/2018] [Indexed: 05/08/2023]
Abstract
There is growing evidence that environmental toxicants can affect various physiological processes by altering DNA methylation patterns. However, very little is known about the impact of toxicant-induced DNA methylation changes on gene expression patterns. The objective of this study was to determine the genome-wide changes in DNA methylation concomitant with altered gene expression patterns in response to 3, 3', 4, 4', 5-pentachlorobiphenyl (PCB126) exposure. We used PCB126 as a model environmental chemical because the mechanism of action is well-characterized, involving activation of aryl hydrocarbon receptor, a ligand-activated transcription factor. Adult zebrafish were exposed to 10 nM PCB126 for 24 h (water-borne exposure) and brain and liver tissues were sampled at 7 days post-exposure in order to capture both primary and secondary changes in DNA methylation and gene expression. We used enhanced Reduced Representation Bisulfite Sequencing and RNAseq to quantify DNA methylation and gene expression, respectively. Enhanced reduced representation bisulfite sequencing analysis revealed 573 and 481 differentially methylated regions in the liver and brain, respectively. Most of the differentially methylated regions are located more than 10 kilobases upstream of transcriptional start sites of the nearest neighboring genes. Gene Ontology analysis of these genes showed that they belong to diverse physiological pathways including development, metabolic processes and regeneration. RNAseq results revealed differential expression of genes related to xenobiotic metabolism, oxidative stress and energy metabolism in response to polychlorinated biphenyl exposure. There was very little correlation between differentially methylated regions and differentially expressed genes suggesting that the relationship between methylation and gene expression is dynamic and complex, involving multiple layers of regulation.
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Affiliation(s)
- Neelakanteswar Aluru
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Correspondence address. Department of Biology, Woods Hole Oceanographic Institution, 45 Water Street, Woods Hole, MA 02543, USA. Tel: 508-289-3607; Fax: 508-457-2134; E-mail:
| | - Sibel I Karchner
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Keegan S Krick
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Wei Zhu
- CAS Key Laboratory of Genomic Sciences and Information, Collaborative Innovation Center of Genetics and Development, Beijing Institute of Genomics, CAS, Beijing 100101, China
| | - Jiang Liu
- CAS Key Laboratory of Genomic Sciences and Information, Collaborative Innovation Center of Genetics and Development, Beijing Institute of Genomics, CAS, Beijing 100101, China
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Desaulniers D, Cummings-Lorbetskie C, Li N, Xiao GH, Marro L, Khan N, Leingartner K. Sodium bisulfite pyrosequencing revealed that developmental exposure to environmental contaminant mixtures does not affect DNA methylation of DNA repeats in Sprague-Dawley rats. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2016; 80:32-52. [PMID: 27905861 DOI: 10.1080/15287394.2016.1231644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/29/2016] [Indexed: 06/06/2023]
Abstract
Hypomethylation of DNA repeats has been linked to diseases and cancer predisposition. Human studies suggest that higher blood concentrations of environmental contaminants (EC) correlate with levels of hypomethylation of DNA repeats in blood. The objective of this study was to examine the effect of in utero and/or lactational exposure to EC on the methylation of DNA repeats (LINE-1 and identifier element) in Sprague-Dawley rat pups at birth, at postnatal day (PND) 21, and in adulthood (PND78-86). From gestation day 0 to PND20, dams were exposed to a mixture "M" of polychlorinated biphenyls (PCB), pesticides, and methylmercury (MeHg), at 0.5 or 1 mg/kg/d (0.5M and M). At birth, some control (C) and M litters were cross-fostered to create the following in utero/postnatal exposure groups: C/C, M/C, C/M, M/M. Additional dams received 1.8 ng/kg/d of a mixture of aryl-hydrocarbon receptor (AhR) agonists (non-ortho-PCB, PC-dibenzodioxins, and PC-dibenzofurans) without or with 0.5M (0.5MAhR). Measurements of EC residue levels confirmed differences in their accumulation across treatments, age, and tissues. Although induction of hepatic detoxification enzyme activities (cytochrome P-450) demonstrated biological effects of treatments, the assessment of methylation in DNA repeats by sodium bisulfite pyrosequencing of liver, spleen, and thymus samples revealed no marked treatment-related effects but significant tissue- and age-related methylation differences. Further studies are required to determine whether absence of significant observable treatment effects on methylation of DNA repeats in the rat relate to tissue, strain, or species differences.
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Affiliation(s)
- Daniel Desaulniers
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Cathy Cummings-Lorbetskie
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Nanqin Li
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Gong-Hua Xiao
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Leonora Marro
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Nasrin Khan
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Karen Leingartner
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
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Xing H, Wang C, Wu H, Chen D, Li S, Xu S. Effects of atrazine and chlorpyrifos on DNA methylation in the brain and gonad of the common carp. Comp Biochem Physiol C Toxicol Pharmacol 2015; 168:11-9. [PMID: 25460047 DOI: 10.1016/j.cbpc.2014.11.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 11/06/2014] [Accepted: 11/12/2014] [Indexed: 12/28/2022]
Abstract
DNA methylation is known to play an important role in the regulation of gene expression in animal. The purpose of the present study was to examine the effect of atrazine (ATR), chlorpyrifos (CPF) and combined ATR/CPF exposure on DNA methylation in the brain and gonad of common carp (Cyprinus carpio L.). The carp were sampled after a 40-d exposure to CPF and ATR, individually or in combination, followed by a 40-d recovery to measure the levels of global DNA methylation and the expression of methylation enzymes (DNA methyltransferases (DNMTs) and methylcytosine binding domain 2 (MBD2)) in the brain and gonad tissues. The results revealed that a significant global DNA hypomethylation in the common carp exposed to ATR, CPF and their mixture was observed compared to the control fish. The MBD2 mRNA expression was up-regulated in the brain and gonad of the common carp exposed to ATR, CPF and their mixture, in contrast, the DNMTs mRNA expression was down-regulated. The information regarding the effects of ATR and CPF on DNA methylation status generated in this study is important for pesticides toxicology evaluation. However, the effect of ATR and CPF on the methylation status of specific genes, as well as its detailed mechanism requires further investigation.
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Affiliation(s)
- Houjuan Xing
- College of Animal Science and Technology, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, China; Animal Health Supervision Institute of Heilongjiang Province, 243 Haping Road, Xiangfang District, Harbin 150069, PR China
| | - Chao Wang
- College of Animal Science and Technology, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, China
| | - Hongda Wu
- Institute of Animal Science, Academy of Agricultural Sciences of Heilongjiang Province, 368 Xuefu Road, Xiangfang District, Harbin 150086, PR China
| | - Dechun Chen
- College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, China
| | - Shu Li
- College of Animal Science and Technology, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, China; College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, China.
| | - Shiwen Xu
- College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, China.
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