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Iqbal K, Pierce SH, Kozai K, Dhakal P, Scott RL, Roby KF, Vyhlidal CA, Soares MJ. Evaluation of Placentation and the Role of the Aryl Hydrocarbon Receptor Pathway in a Rat Model of Dioxin Exposure. ENVIRONMENTAL HEALTH PERSPECTIVES 2021; 129:117001. [PMID: 34747641 PMCID: PMC8574979 DOI: 10.1289/ehp9256] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
BACKGROUND Our environment is replete with chemicals that can affect embryonic and extraembryonic development. Dioxins, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), are compounds affecting development through the aryl hydrocarbon receptor (AHR). OBJECTIVES The purpose of this investigation was to examine the effects of TCDD exposure on pregnancy and placentation and to evaluate roles for AHR and cytochrome P450 1A1 (CYP1A1) in TCDD action. METHODS Actions of TCDD were examined in wild-type and genome-edited rat models. Placenta phenotyping was assessed using morphological, biochemical, and molecular analyses. RESULTS TCDD exposures were shown to result in placental adaptations and at higher doses, pregnancy termination. Deep intrauterine endovascular trophoblast cell invasion was a prominent placentation site adaptation to TCDD. TCDD-mediated placental adaptations were dependent upon maternal AHR signaling but not upon placental or fetal AHR signaling nor the presence of a prominent AHR target, CYP1A1. At the placentation site, TCDD activated AHR signaling within endothelial cells but not trophoblast cells. Immune and trophoblast cell behaviors at the uterine-placental interface were guided by the actions of TCDD on endothelial cells. DISCUSSION We identified an AHR regulatory pathway in rats activated by dioxin affecting uterine and trophoblast cell dynamics and the formation of the hemochorial placenta. https://doi.org/10.1289/EHP9256.
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Affiliation(s)
- Khursheed Iqbal
- Institute for Reproduction and Perinatal Research, University of Kansas Medical Center (KUMC), Kansas City, Kansas, USA
- Department of Pathology and Laboratory Medicine, KUMC, Kansas City, Kansas, USA
| | - Stephen H. Pierce
- Institute for Reproduction and Perinatal Research, University of Kansas Medical Center (KUMC), Kansas City, Kansas, USA
- Department of Pathology and Laboratory Medicine, KUMC, Kansas City, Kansas, USA
| | - Keisuke Kozai
- Institute for Reproduction and Perinatal Research, University of Kansas Medical Center (KUMC), Kansas City, Kansas, USA
- Department of Pathology and Laboratory Medicine, KUMC, Kansas City, Kansas, USA
| | - Pramod Dhakal
- Institute for Reproduction and Perinatal Research, University of Kansas Medical Center (KUMC), Kansas City, Kansas, USA
- Department of Pathology and Laboratory Medicine, KUMC, Kansas City, Kansas, USA
| | - Regan L. Scott
- Institute for Reproduction and Perinatal Research, University of Kansas Medical Center (KUMC), Kansas City, Kansas, USA
- Department of Pathology and Laboratory Medicine, KUMC, Kansas City, Kansas, USA
| | - Katherine F. Roby
- Institute for Reproduction and Perinatal Research, University of Kansas Medical Center (KUMC), Kansas City, Kansas, USA
- Department of Anatomy and Cell Biology, KUMC, Kansas City, Kansas, USA
| | - Carrie A. Vyhlidal
- Institute for Reproduction and Perinatal Research, University of Kansas Medical Center (KUMC), Kansas City, Kansas, USA
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Children’s Mercy Kansas City, Kansas City, Missouri
- Center for Perinatal Research, Children’s Mercy Research Institute, Children’s Mercy Kansas City, Kansas City, Missouri
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri
| | - Michael J. Soares
- Institute for Reproduction and Perinatal Research, University of Kansas Medical Center (KUMC), Kansas City, Kansas, USA
- Department of Pathology and Laboratory Medicine, KUMC, Kansas City, Kansas, USA
- Center for Perinatal Research, Children’s Mercy Research Institute, Children’s Mercy Kansas City, Kansas City, Missouri
- Department of Obstetrics and Gynecology, KUMC, Kansas City, Kansas, USA
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Pellizzari ED, Woodruff TJ, Boyles RR, Kannan K, Beamer PI, Buckley JP, Wang A, Zhu Y, Bennett DH. Identifying and Prioritizing Chemicals with Uncertain Burden of Exposure: Opportunities for Biomonitoring and Health-Related Research. ENVIRONMENTAL HEALTH PERSPECTIVES 2019; 127:126001. [PMID: 31850800 PMCID: PMC6957289 DOI: 10.1289/ehp5133] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 11/13/2019] [Accepted: 11/19/2019] [Indexed: 05/18/2023]
Abstract
BACKGROUND The National Institutes of Health's Environmental influences on Child Health Outcomes (ECHO) initiative aims to understand the impact of environmental factors on childhood disease. Over 40,000 chemicals are approved for commercial use. The challenge is to prioritize chemicals for biomonitoring that may present health risk concerns. OBJECTIVES Our aim was to prioritize chemicals that may elicit child health effects of interest to ECHO but that have not been biomonitored nationwide and to identify gaps needing additional research. METHODS We searched databases and the literature for chemicals in environmental media and in consumer products that were potentially toxic. We selected chemicals that were not measured in the National Health and Nutrition Examination Survey. From over 700 chemicals, we chose 155 chemicals and created eight chemical panels. For each chemical, we compiled biomonitoring and toxicity data, U.S. Environmental Protection Agency exposure predictions, and annual production usage. We also applied predictive modeling to estimate toxicity. Using these data, we recommended chemicals either for biomonitoring, to be deferred pending additional data, or as low priority for biomonitoring. RESULTS For the 155 chemicals, 97 were measured in food or water, 67 in air or house dust, and 52 in biospecimens. We found in vivo endocrine, developmental, reproductive, and neurotoxic effects for 61, 74, 47, and 32 chemicals, respectively. Eighty-six had data from high-throughput in vitro assays. Positive results for endocrine, developmental, neurotoxicity, and obesity were observed for 32, 11, 35, and 60 chemicals, respectively. Predictive modeling results suggested 90% are toxicants. Biomarkers were reported for 76 chemicals. Thirty-six were recommended for biomonitoring, 108 deferred pending additional research, and 11 as low priority for biomonitoring. DISCUSSION The 108 deferred chemicals included those lacking biomonitoring methods or toxicity data, representing an opportunity for future research. Our evaluation was, in general, limited by the large number of unmeasured or untested chemicals. https://doi.org/10.1289/EHP5133.
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Affiliation(s)
- Edo D. Pellizzari
- Fellow Program, RTI International, Research Triangle Park, North Carolina, USA
| | - Tracey J. Woodruff
- Program on Reproductive Health and the Environment, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Rebecca R. Boyles
- Bioinformatics and Data Science, RTI International, Research Triangle Park, North Carolina, USA
| | | | - Paloma I. Beamer
- Department of Community, Environment and Policy, Zuckerman College of Public Health, University of Arizona, Tucson, Arizona, USA
| | - Jessie P. Buckley
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Heath, Johns Hopkins University, Baltimore, Maryland, USA
| | - Aolin Wang
- Program on Reproductive Health and the Environment, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Yeyi Zhu
- Northern California Division of Research, Kaiser Permanente, Oakland, California, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California, USA
| | - Deborah H. Bennett
- Department of Public Health Sciences, University of California, Davis, Davis, California, USA
| | - (Environmental influences on Child Health Outcomes)
- Fellow Program, RTI International, Research Triangle Park, North Carolina, USA
- Program on Reproductive Health and the Environment, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA
- Bioinformatics and Data Science, RTI International, Research Triangle Park, North Carolina, USA
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Community, Environment and Policy, Zuckerman College of Public Health, University of Arizona, Tucson, Arizona, USA
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Heath, Johns Hopkins University, Baltimore, Maryland, USA
- Northern California Division of Research, Kaiser Permanente, Oakland, California, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California, USA
- Department of Public Health Sciences, University of California, Davis, Davis, California, USA
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Latchney SE, Lioy DT, Henry EC, Gasiewicz TA, Strathmann FG, Mayer-Pröschel M, Opanashuk LA. Neural precursor cell proliferation is disrupted through activation of the aryl hydrocarbon receptor by 2,3,7,8-tetrachlorodibenzo-p-dioxin. Stem Cells Dev 2010; 20:313-26. [PMID: 20486776 DOI: 10.1089/scd.2009.0529] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Neurogenesis involves the proliferation of multipotent neuroepithelial stem cells followed by differentiation into lineage-restricted neural precursor cells (NPCs) during the embryonic period. Interestingly, these progenitor cells express robust levels of the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that regulates expression of genes important for growth regulation, and xenobiotic metabolism. Upon binding 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a pervasive environmental contaminant and potent AhR ligand, AhR, is activated and disrupts gene expression patterns to produce cellular toxicity. Because of its widespread distribution in the brain during critical proliferative phases of neurogenesis, it is conceivable that AhR participates in NPC expansion. Therefore, this study tested the hypothesis that AhR activation by TCDD disrupts signaling events that regulate NPC proliferation. The C17.2 NPC line served as a model system to (1) assess whether NPCs are targets for TCDD-induced neurotoxicity and (2) characterize the effects of TCDD on NPC proliferation. We demonstrated that C17.2 NPCs express an intact AhR signaling pathway that becomes transcriptionally active after TCDD exposure. (3)H-thymidine and alamar blue reduction assays indicated that TCDD suppresses NPC proliferation in a concentration-dependent manner without the loss of cell viability. Cell cycle distribution analysis by flow cytometry revealed that TCDD-induced growth arrest results from an impaired G1 to S cell cycle transition. Moreover, TCDD exposure altered p27( kip1) and cyclin D1 cell cycle regulatory protein expression levels consistent with a G1 phase arrest. Initial studies in primary NPCs isolated from the ventral forebrain of embryonic mice demonstrated that TCDD reduced cell proliferation through a G1 phase arrest, corroborating our findings in the C17.2 cell line. Together, these observations suggest that the inappropriate or sustained activation of AhR by TCDD during neurogenesis can interfere with signaling pathways that regulate neuroepithelial stem cell/NPC proliferation, which could adversely impact final cell number in the brain and lead to functional impairments.
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Affiliation(s)
- Sarah E Latchney
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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