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Lukowicz C, Ellero-Simatos S, Régnier M, Polizzi A, Lasserre F, Montagner A, Lippi Y, Jamin EL, Martin JF, Naylies C, Canlet C, Debrauwer L, Bertrand-Michel J, Al Saati T, Théodorou V, Loiseau N, Mselli-Lakhal L, Guillou H, Gamet-Payrastre L. Metabolic Effects of a Chronic Dietary Exposure to a Low-Dose Pesticide Cocktail in Mice: Sexual Dimorphism and Role of the Constitutive Androstane Receptor. ENVIRONMENTAL HEALTH PERSPECTIVES 2018; 126:067007. [PMID: 29950287 PMCID: PMC6084886 DOI: 10.1289/ehp2877] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 04/27/2018] [Accepted: 04/28/2018] [Indexed: 05/03/2023]
Abstract
BACKGROUND Epidemiological evidence suggests a link between pesticide exposure and the development of metabolic diseases. However, most experimental studies have evaluated the metabolic effects of pesticides using individual molecules, often at nonrelevant doses or in combination with other risk factors such as high-fat diets. OBJECTIVES We aimed to evaluate, in mice, the metabolic consequences of chronic dietary exposure to a pesticide mixture at nontoxic doses, relevant to consumers' risk assessment. METHODS A mixture of six pesticides commonly used in France, i.e., boscalid, captan, chlorpyrifos, thiofanate, thiacloprid, and ziram, was incorporated in a standard chow at doses exposing mice to the tolerable daily intake (TDI) of each pesticide. Wild-type (WT) and constitutive androstane receptor-deficient (CAR-/-) male and female mice were exposed for 52 wk. We assessed metabolic parameters [body weight (BW), food and water consumption, glucose tolerance, urinary metabolome] throughout the experiment. At the end of the experiment, we evaluated liver metabolism (histology, transcriptomics, metabolomics, lipidomics) and pesticide detoxification using liquid chromatography-mass spectrometry (LC-MS). RESULTS Compared to those fed control chow, WT male mice fed pesticide chow had greater BW gain and more adiposity. Moreover, these WT males fed pesticide chow exhibited characteristics of hepatic steatosis and glucose intolerance, which were not observed in those fed control chow. WT exposed female mice exhibited fasting hyperglycemia, higher reduced glutathione (GSH):oxidized glutathione (GSSG) liver ratio and perturbations of gut microbiota-related urinary metabolites compared to WT mice fed control chow. When we performed these experiments on CAR-/- mice, pesticide-exposed CAR-/- males did not exhibit BW gain or changes in glucose metabolism compared to the CAR-/- males fed control chow. Moreover, CAR-/- females fed pesticide chow exhibited pesticide toxicity with higher BWs and mortality rate compared to the CAR-/- females fed control chow. CONCLUSIONS To our knowledge, we are the first to demonstrate a sexually dimorphic obesogenic and diabetogenic effect of chronic dietary exposure to a common mixture of pesticides at TDI levels, and to provide evidence for a partial role for CAR in an in vivo mouse model. This raises questions about the relevance of TDI for individual pesticides when present in a mixture. https://doi.org/10.1289/EHP2877.
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Affiliation(s)
- Céline Lukowicz
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
| | - Sandrine Ellero-Simatos
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
| | - Marion Régnier
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
| | - Arnaud Polizzi
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
| | - Frédéric Lasserre
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
| | - Alexandra Montagner
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
| | - Yannick Lippi
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
| | - Emilien L Jamin
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
- Axiom Platform, MetaToul-MetaboHUB, National Infrastructure for Metabolomics and Fluxomics, Toulouse, France
| | - Jean-François Martin
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
| | - Claire Naylies
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
| | - Cécile Canlet
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
- Axiom Platform, MetaToul-MetaboHUB, National Infrastructure for Metabolomics and Fluxomics, Toulouse, France
| | - Laurent Debrauwer
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
- Axiom Platform, MetaToul-MetaboHUB, National Infrastructure for Metabolomics and Fluxomics, Toulouse, France
| | - Justine Bertrand-Michel
- Plateforme Lipidomique Inserm/UPS UMR 1048 - I2MC Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Talal Al Saati
- Service d’histopathologie Expérimentale Unité Inserm/UPS/ENVT -US006/CREFRE Inserm, Bât. F, CHU Purpan, Toulouse, France
| | - Vassilia Théodorou
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
| | - Nicolas Loiseau
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
| | - Laïla Mselli-Lakhal
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
| | - Hervé Guillou
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
| | - Laurence Gamet-Payrastre
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, Université Paul Sabatier, Toulouse, France
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Oliveri AN, Ortiz E, Levin ED. Developmental exposure to an organophosphate flame retardant alters later behavioral responses to dopamine antagonism in zebrafish larvae. Neurotoxicol Teratol 2018; 67:25-30. [PMID: 29559250 DOI: 10.1016/j.ntt.2018.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/16/2018] [Accepted: 03/16/2018] [Indexed: 02/07/2023]
Abstract
Human exposure to organophosphate flame retardants (OPFRs) is widespread, including pregnant women and young children with whom developmental neurotoxic risk is a concern. Given similarities of OPFRs to organophosphate (OP) pesticides, research into the possible neurotoxic impacts of developmental OPFR exposure has been growing. Building upon research implicating exposure to OP pesticides in dopaminergic (DA) dysfunction, we exposed developing zebrafish to the OPFR tris(1,3-dichloroisopropyl) phosphate (TDCIPP), during the first 5 days following fertilization. On day 6, larvae were challenged with acute administration of dopamine D1 and D2 receptor antagonists and then tested in a light-dark locomotor assay. We found that both developmental TDCIPP exposure and acute dopamine D1 and D2 antagonism decreased locomotor activity separately. The OPFR and DA effects were not additive; rather, TDCIPP blunted further D1 and D2 antagonist-induced decreases in activity. Our results suggest that TDCIPP exposure may be disrupting dopamine signaling. These findings support further research on the effects of OPFR exposure on the normal neurodevelopment of DA systems, whether these results might persist into adulthood, and whether they interact with OPFR effects on other neurotransmitter systems in producing the developmental neurobehavioral toxicity.
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Affiliation(s)
- Anthony N Oliveri
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Erica Ortiz
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
| | - Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA.
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Guo-Ross SX, Meek EC, Chambers JE, Carr RL. Effects of Chlorpyrifos or Methyl Parathion on Regional Cholinesterase Activity and Muscarinic Receptor Subtype Binding in Juvenile Rat Brain. JOURNAL OF TOXICOLOGY AND PHARMACOLOGY 2017; 1:018. [PMID: 30035273 PMCID: PMC6052801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The effects of developmental exposure to two organophosphorus (OP) insecticides, chlorpyrifos (CPF) and methyl parathion (MPS), on cholinesterase (ChE) activity and muscarinic acetylcholine receptor (mAChR) binding were investigated in preweanling rat brain. Animals were orally gavaged daily with low, medium, and high dosages of the insecticides using an incremental dosing regimen from postnatal day 1 (PND1) to PND20. On PND12, PND17 and PND20, the cerebral cortex, corpus striatum, hippocampus, and medulla-pons were collected for determination of ChE activity, total mAChR density, and the density of the individual mAChR subtypes. ChE activity was inhibited by the medium and high dosages of CPF and MPS at equal levels in all four brain regions at all three ages examined. Exposure to both compounds decreased the levels of the M1, M2/M4, and M3 subtypes and the total mAChR level in all brain regions, but the effects varied by dosage group and brain region. On PND12, only the high dosages induced receptor changes while on PND17 and PND20, greater effects became evident. In general, the effects on the M1 subtype and total receptor levels appeared to be greater in the cerebral cortex and hippocampus than in the corpus striatum and medulla-pons. This did not appear to be the case for the M2/M4 and M3 subtypes effects. The differences between CPF and MPS were minimal even though in some cases, CPF exerted statistically greater effects than MPS did. In general, repeated exposure to organophosphorus insecticides can alter the levels of the various mAChR subtypes in various brain regions which could induce perturbation in cholinergic neurochemistry during the maturation of the brain regions.
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Ginsberg G, Vulimiri SV, Lin YS, Kancherla J, Foos B, Sonawane B. A framework and case studies for evaluation of enzyme ontogeny in children's health risk evaluation. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2017; 80:569-593. [PMID: 28891786 PMCID: PMC8018602 DOI: 10.1080/15287394.2017.1369915] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Knowledge of the ontogeny of Phase I and Phase II metabolizing enzymes may be used to inform children's vulnerability based upon likely differences in internal dose from xenobiotic exposure. This might provide a qualitative assessment of toxicokinetic (TK) variability and uncertainty pertinent to early lifestages and help scope a more quantitative physiologically based toxicokinetic (PBTK) assessment. Although much is known regarding the ontogeny of metabolizing systems, this is not commonly utilized in scoping and problem formulation stage of human health risk evaluation. A framework is proposed for introducing this information into problem formulation which combines data on enzyme ontogeny and chemical-specific TK to explore potential child/adult differences in internal dose and whether such metabolic differences may be important factors in risk evaluation. The framework is illustrated with five case study chemicals, including some which are data rich and provide proof of concept, while others are data poor. Case studies for toluene and chlorpyrifos indicate potentially important child/adult TK differences while scoping for acetaminophen suggests enzyme ontogeny is unlikely to increase early-life risks. Scoping for trichloroethylene and aromatic amines indicates numerous ways that enzyme ontogeny may affect internal dose which necessitates further evaluation. PBTK modeling is a critical and feasible next step to further evaluate child-adult differences in internal dose for a number of these chemicals.
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Affiliation(s)
- Gary Ginsberg
- Partnership in Pediatric and Environmental Health, Hartford, CT 06134, USA
| | - Suryanarayana V. Vulimiri
- National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC 20460, USA
| | - Yu-Sheng Lin
- National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC 20460, USA
| | - Jayaram Kancherla
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD, 20740, USA
| | - Brenda Foos
- Office of Children’s Health Protection, U.S. Environmental Protection Agency, Washington, DC, USA
| | - Babasaheb Sonawane
- National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC 20460, USA
- Current Address: 13204 Moran Drive, North Potomac, MD 20878
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Abreu-Villaça Y, Levin ED. Developmental neurotoxicity of succeeding generations of insecticides. ENVIRONMENT INTERNATIONAL 2017; 99:55-77. [PMID: 27908457 PMCID: PMC5285268 DOI: 10.1016/j.envint.2016.11.019] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 11/17/2016] [Accepted: 11/17/2016] [Indexed: 05/19/2023]
Abstract
Insecticides are by design toxic. They must be toxic to effectively kill target species of insects. Unfortunately, they also have off-target toxic effects that can harm other species, including humans. Developmental neurotoxicity is one of the most prominent off-target toxic risks of insecticides. Over the past seven decades several classes of insecticides have been developed, each with their own mechanisms of effect and toxic side effects. This review covers the developmental neurotoxicity of the succeeding generations of insecticides including organochlorines, organophosphates, pyrethroids, carbamates and neonicotinoids. The goal of new insecticide development is to more effectively kill target species with fewer toxic side effects on non-target species. From the experience with the developmental neurotoxicity caused by the generations of insecticides developed in the past advice is offered how to proceed with future insecticide development to decrease neurotoxic risk.
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Affiliation(s)
- Yael Abreu-Villaça
- Departamento de Ciências Fisiologicas, Universidade do Estado do Rio de Janeiro (UERJ), RJ, Brazil
| | - Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA.
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Pei Y, Peng J, Behl M, Sipes NS, Shockley KR, Rao MS, Tice RR, Zeng X. Comparative neurotoxicity screening in human iPSC-derived neural stem cells, neurons and astrocytes. Brain Res 2016; 1638:57-73. [PMID: 26254731 PMCID: PMC5032144 DOI: 10.1016/j.brainres.2015.07.048] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 07/24/2015] [Accepted: 07/28/2015] [Indexed: 12/14/2022]
Abstract
Induced pluripotent stem cells (iPSC) and their differentiated derivatives offer a unique source of human primary cells for toxicity screens. Here, we report on the comparative cytotoxicity of 80 compounds (neurotoxicants, developmental neurotoxicants, and environmental compounds) in iPSC as well as isogenic iPSC-derived neural stem cells (NSC), neurons, and astrocytes. All compounds were tested over a 24-h period at 10 and 100 μM, in duplicate, with cytotoxicity measured using the MTT assay. Of the 80 compounds tested, 50 induced significant cytotoxicity in at least one cell type; per cell type, 32, 38, 46, and 41 induced significant cytotoxicity in iPSC, NSC, neurons, and astrocytes, respectively. Four compounds (valinomycin, 3,3',5,5'-tetrabromobisphenol, deltamethrin, and triphenyl phosphate) were cytotoxic in all four cell types. Retesting these compounds at 1, 10, and 100 μM using the same exposure protocol yielded consistent results as compared with the primary screen. Using rotenone, we extended the testing to seven additional iPSC lines of both genders; no substantial difference in the extent of cytotoxicity was detected among the cell lines. Finally, the cytotoxicity assay was simplified by measuring luciferase activity using lineage-specific luciferase reporter iPSC lines which were generated from the parental iPSC line. This article is part of a Special Issue entitled SI: PSC and the brain.
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Affiliation(s)
- Ying Pei
- XCell Science Inc., Novato, CA, USA
| | - Jun Peng
- Buck Institute for Research on Aging, Novato, CA, USA
| | - Mamta Behl
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27713, USA
| | - Nisha S Sipes
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27713, USA
| | - Keith R Shockley
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27713, USA
| | | | - Raymond R Tice
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27713, USA
| | - Xianmin Zeng
- XCell Science Inc., Novato, CA, USA; Buck Institute for Research on Aging, Novato, CA, USA.
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Abstract
Children are especially vulnerable to environmental pollution, a major cause of disease, death, and disability in countries at every level of development. This article reviews threats to children, including air and water pollution, toxic industrial chemicals, pesticides, heavy metals, and hazardous wastes. Global climate change is expected to exacerbate many of these issues. Examples of innovative nongovernmental organizations and governmental programs that address the impacts of environmental hazards on children are included. International travel, adoption, migration, and movement of goods and pollutants worldwide make these conditions concerns for all pediatricians.
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Affiliation(s)
- Mark D Miller
- Children's Environmental Health Program, Office of Environmental Health Hazard Assessment, California EPA, 1515 Clay Street, 16th Floor, Oakland, CA 94612, USA; Western States Pediatric Environmental Health Specialty Unit at UCSF, SFGH, Occupational Environmental Medicine, Box 0843, San Francisco, CA 94143-0843, USA.
| | - Melanie A Marty
- Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, 1001 I Street, Sacramento, CA 95814, USA
| | - Philip J Landrigan
- Arnhold Institute for Global Health, Icahn School of Medicine at Mount Sinai, 17 East 102nd Street, Room D3-145, New York, NY 10029-6574, USA
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Meijer M, Hamers T, Westerink RH. Acute disturbance of calcium homeostasis in PC12 cells as a novel mechanism of action for (sub)micromolar concentrations of organophosphate insecticides. Neurotoxicology 2014; 43:110-116. [DOI: 10.1016/j.neuro.2014.01.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 01/02/2014] [Accepted: 01/18/2014] [Indexed: 12/26/2022]
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ElMazoudy RH, Attia AA. Endocrine-disrupting and cytotoxic potential of anticholinesterase insecticide, diazinon in reproductive toxicity of male mice. JOURNAL OF HAZARDOUS MATERIALS 2012; 209-210:111-120. [PMID: 22284168 DOI: 10.1016/j.jhazmat.2011.12.073] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 12/04/2011] [Accepted: 12/28/2011] [Indexed: 05/31/2023]
Abstract
We evaluated the effects of diazinon (2, 4.1 and 8.2mg/kg bw/day for 4 weeks) in gonadotropins, testosterone and estrogen levels, whether the regulatory interactions in the hypothalamic-pituitary-testicular axis are modified by acetylcholinesterase inhibition and histopathological changes in adult mice testes. Diazinon at doses higher than 2mg/kg bw/day resulted in decreased testis weight, inhibition in acetylcholinesterase activities, decrease in levels of luteinizing hormone and follicle stimulating hormone, following reduction in mating and fertility indices. Diazinon increased testosterone content in 4.1mg/kg group, but decreased testosterone concentration in 8.2mg/kg group. Diazinon increased estrogen, prolactine and decreased levels of acetylcholinesterase activities in 4.1mg/kg group but levels of luteinizing hormone and follicle stimulating hormone remained unmodified. It may be simply postulated a scenario that acetylcholine in the cholinergic neurons has a potential threshold to perform a crucial part in the complex circuitry of neuroendocrine regulatory mechanisms. On overaccumulation, other neurotransmitters can be appropriately recruited to modulate the mechanisms of circuitry.
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Affiliation(s)
- Reda H ElMazoudy
- Zoology Department, Faculty of Science, Alexandria University, Alexandria, Egypt.
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Prueitt RL, Goodman JE, Bailey LA, Rhomberg LR. Hypothesis-based weight-of-evidence evaluation of the neurodevelopmental effects of chlorpyrifos. Crit Rev Toxicol 2011; 41:822-903. [PMID: 22085162 DOI: 10.3109/10408444.2011.616877] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Slotkin TA. Does early-life exposure to organophosphate insecticides lead to prediabetes and obesity? Reprod Toxicol 2010; 31:297-301. [PMID: 20850519 DOI: 10.1016/j.reprotox.2010.07.012] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Accepted: 07/30/2010] [Indexed: 12/18/2022]
Abstract
Human exposures to organophosphate insecticides are ubiquitous. Although regarded as neurotoxicants, increasing evidence points toward lasting metabolic disruption from early-life organophosphate exposures. We gave neonatal rats chlorpyrifos, diazinon or parathion in doses devoid of any acute signs of toxicity, straddling the threshold for barely-detectable cholinesterase inhibition. Organophosphate exposure during a critical developmental window altered the trajectory of hepatic adenylyl cyclase/cyclic AMP signaling, culminating in hyperresponsiveness to gluconeogenic stimuli. Consequently, the animals developed metabolic dysfunction resembling prediabetes. When the organophosphate-exposed animals consumed a high fat diet in adulthood, metabolic defects were exacerbated and animals gained excess weight compared to unexposed rats on the same diet. At the same time, the high fat diet ameliorated many of the central synaptic defects caused by organophosphate exposure, pointing to nonpharmacologic therapeutic interventions to offset neurodevelopmental abnormalities, as well as toward fostering dietary choices favoring high fat intake. These studies show how common insecticides may contribute to the increased worldwide incidence of obesity and diabetes.
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Affiliation(s)
- Theodore A Slotkin
- Department of Pharmacology and Cancer Biology, DUMC, Duke University Medical Center, Durham, NC 27710, USA.
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Slotkin TA, Seidler FJ. Diverse neurotoxicants converge on gene expression for neuropeptides and their receptors in an in vitro model of neurodifferentiation: effects of chlorpyrifos, diazinon, dieldrin and divalent nickel in PC12 cells. Brain Res 2010; 1353:36-52. [PMID: 20682304 DOI: 10.1016/j.brainres.2010.07.073] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 07/14/2010] [Accepted: 07/21/2010] [Indexed: 11/17/2022]
Abstract
Unrelated developmental neurotoxicants can produce similar neurobehavioral outcomes. We examined whether disparate agents affect neuromodulators that control numerous neurotransmitters and circuits, employing PC12 cells to explore the targeting of neuroactive peptides by organophosphates (chlorpyrifos, diazinon), an organochlorine (dieldrin) and a metal (Ni(2+)); we utilized microarrays to profile gene expression for the peptides and their receptors. Chlorpyrifos evoked robust upregulation of cholecystokinin, corticotropin releasing hormone, galanin, neuropeptide Y, neurotensin, preproenkephalin and tachykinin 1; this involved a critical period at the commencement of neurodifferentiation, since the effects were much less notable in undifferentiated PC12 cells. Diazinon targeted a similar but smaller repertoire of neuropeptide genes and the magnitude of the effects was also generally less. Surprisingly, dieldrin shared many of the same neuropeptide targets as the organophosphates and concordance analysis showed significant overlap among all three pesticides. However, dieldrin had more notable effects on neuropeptide receptors, and overlap between diazinon and dieldrin for the receptors led to a stronger resemblance of these two agents than of chlorpyrifos and dieldrin. Ni(2+) was unique, evoking upregulation of only one of the peptides affected by the other agents, while causing downregulation of several others. Nevertheless, there was still significant concordance between Ni(2+) and either diazinon or dieldrin, reflecting similarities toward the receptors. Our results show that neuropeptides are likely to be a prominent target for the developmental neurotoxicity of organophosphates and other neurotoxicants, and further, that the convergence of disparate agents on the same genes and pathways may contribute to similar neurobehavioral outcomes.
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Affiliation(s)
- Theodore A Slotkin
- Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
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