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Holuka C, Morel C, Roth S, Lamartinière Y, Mériaux SB, Paoli J, Guébels P, Duca RC, Godderis L, van Nieuwenhuyse A, Kremarik-Bouillaud P, Cariou R, Emond C, Schroeder H, Turner JD, Grova N. The epigenetic hallmark of early-life α-hexabromocyclododecane exposure: From cerebellar 6-mA levels to locomotor performance in adulthood. ENVIRONMENT INTERNATIONAL 2023; 178:108103. [PMID: 37494814 DOI: 10.1016/j.envint.2023.108103] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 07/18/2023] [Accepted: 07/18/2023] [Indexed: 07/28/2023]
Abstract
There is a growing evidence that methylation at the N6 position of adenine (6-mA), whose modulation occurs primarily during development, would be a reliable epigenetic marker in eukaryotic organisms. The present study raises the question as to whether early-life exposure to α-hexabromocyclododecane (α-HBCDD), a brominated flame retardant, may trigger modifications in 6-mA epigenetic hallmarks in the brain during the development which, in turn could affect the offspring behaviour in adulthood. Pregnant Wistar rats were split into two groups: control and α-HBCDD (66 ng/kg/per os, G0-PND14). At PND1, α-HBCDD levels were assessed in brain and liver by LC-MS/MS. At PND14, DNA was isolated from the offspring's cerebellum. DNA methylation was measured by 6-mA-specific immunoprecipitation and Illumina® sequencing (MEDIP-Seq). Locomotor activity was finally evaluated at PND120. In our early-life exposure model, we confirmed that α-HBCDD can cross the placental barrier and be detected in pups at birth. An obvious post-exposure phenotype with locomotor deficits was observed when the rats reached adulthood. This was accompanied by sex-specific over-methylation of genes involved in the insulin signaling pathway, MAPK signaling pathway as well as serotonergic and GABAergic synapses, potentially altering the normal process of neurodevelopment with consequent motor impairments crystalized at adulthood.
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Affiliation(s)
- Cyrielle Holuka
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity-Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-Sur-Alzette, Luxembourg; Faculty of Science, University of Luxembourg, L-4365 Belval, Luxembourg.
| | - Chloé Morel
- Calbinotox, Faculty of Science and Technology, University of Lorraine, Campus Aiguillettes, B.P. 70239, 54506 Vandoeuvre-lès-Nancy, France.
| | - Sarah Roth
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity-Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-Sur-Alzette, Luxembourg.
| | - Yordenca Lamartinière
- Calbinotox, Faculty of Science and Technology, University of Lorraine, Campus Aiguillettes, B.P. 70239, 54506 Vandoeuvre-lès-Nancy, France.
| | - Sophie B Mériaux
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity-Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-Sur-Alzette, Luxembourg.
| | - Justine Paoli
- Calbinotox, Faculty of Science and Technology, University of Lorraine, Campus Aiguillettes, B.P. 70239, 54506 Vandoeuvre-lès-Nancy, France.
| | - Pauline Guébels
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity-Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-Sur-Alzette, Luxembourg.
| | - Radu C Duca
- Department of Health Protection, National Health Laboratory (LNS), Dudelange, Luxembourg; Centre for Environment and Health, University of Leuven (KU Leuven), Leuven, Belgium.
| | - Lode Godderis
- Centre for Environment and Health, University of Leuven (KU Leuven), Leuven, Belgium; IDEWE, External Service for Prevention and Protection at Work, Heverlee 3001, Belgium.
| | - An van Nieuwenhuyse
- Department of Health Protection, National Health Laboratory (LNS), Dudelange, Luxembourg; Centre for Environment and Health, University of Leuven (KU Leuven), Leuven, Belgium.
| | - Pascaline Kremarik-Bouillaud
- UMR Inserm 1256 nGERE, Nutrition-Génétique et exposition aux risques environnementaux, Institute of Medical Research (Pôle BMS), University of Lorraine, B.P. 184, 54511 Nancy, France.
| | | | - Claude Emond
- PKSH Inc., Crabtree, Quebec, Canada; School of Public Health, DSEST, University of Montreal, Montreal, Quebec, Canada.
| | - Henri Schroeder
- Calbinotox, Faculty of Science and Technology, University of Lorraine, Campus Aiguillettes, B.P. 70239, 54506 Vandoeuvre-lès-Nancy, France; UMR Inserm 1256 nGERE, Nutrition-Génétique et exposition aux risques environnementaux, Institute of Medical Research (Pôle BMS), University of Lorraine, B.P. 184, 54511 Nancy, France.
| | - Jonathan D Turner
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity-Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-Sur-Alzette, Luxembourg.
| | - Nathalie Grova
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity-Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-Sur-Alzette, Luxembourg; Calbinotox, Faculty of Science and Technology, University of Lorraine, Campus Aiguillettes, B.P. 70239, 54506 Vandoeuvre-lès-Nancy, France; UMR Inserm 1256 nGERE, Nutrition-Génétique et exposition aux risques environnementaux, Institute of Medical Research (Pôle BMS), University of Lorraine, B.P. 184, 54511 Nancy, France.
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Marques ML, Cairrao E. Occurrence and Health Effects of Hexabromocyclododecane: An Updated Review. TOXICS 2023; 11:toxics11050409. [PMID: 37235223 DOI: 10.3390/toxics11050409] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/17/2023] [Accepted: 04/24/2023] [Indexed: 05/28/2023]
Abstract
Hexabromocyclododecane (HBCD) is a non-aromatic compound belonging to the bromine flame retardant family and is a known persistent organic pollutant (POP). This compound accumulates easily in the environment and has a high half-life in water. With a variety of uses, the HBCD is found in house dust, electronics, insulation, and construction. There are several isomers and the most studied are α-, β-, and γ-HBCD. Initially used as a substitute for other flame retardants, the polybrominated diphenyl ethers (PBDEs), the discovery of its role as a POP made HBCD use and manufacturing restricted in Europe and other countries. The adverse effects on the environment and human health have been piling, either as a result from its accumulation or considering its power as an endocrine disruptor (ED). Furthermore, it has also been proven that it has detrimental effects on the neuronal system, endocrine system, cardiovascular system, liver, and the reproductive system. HBCD has also been linked to cytokine production, DNA damage, increased cell apoptosis, increased oxidative stress, and reactive oxygen species (ROS) production. Therefore, this review aims to compile the most recent studies regarding the negative effects of this compound on the environment and human health, describing the possible mechanisms by which this compound acts and its possible toxic effects.
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Affiliation(s)
- Maria Lopes Marques
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal
| | - Elisa Cairrao
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal
- FCS-UBI, Faculty of Health Sciences, University of Beira Interior, 6200-506 Covilhã, Portugal
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3
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Emond C, DeVito MJ, Birnbaum LS. A PBPK model describing the pharmacokinetics of γ-HBCD exposure in mice. Toxicol Appl Pharmacol 2021; 428:115678. [PMID: 34390738 PMCID: PMC8674938 DOI: 10.1016/j.taap.2021.115678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/10/2021] [Accepted: 08/09/2021] [Indexed: 11/22/2022]
Abstract
The brominated flame retardant, hexabromocyclododecane (HBCD), is added-but not bound-to consumer products and is eventually found in the environment and human tissues. Commercial-grade HBCD mixtures contain three major stereoisomers, alpha (α), beta (β), and gamma (γ), that are typically at a ratio of 12%:6%:82%, respectively. Although HBCD is widely used, the toxicological effects from its exposure in humans are not clearly understood. Using a physiologically based pharmacokinetic (PBPK) model could help improve our understanding of the toxicity of HBCD. The aim of this work was to develop a PBPK model, consisting of five permeability limited compartments (i.e., brain, liver, adipose tissue, blood, and rest of the body), to evaluate the pharmacokinetics of γ-HBCD in C57BL/6 mice. Physiological parameters related to body size, organ weights, and blood flow were taken from the literature. All partition coefficients were calculated based on the log Kow. The elimination in urine and feces was optimized to reflect the percent dose eliminated, as published in the literature. Compared with data from the literature for brain, liver, blood, and adipose tissue, the model simulations accurately described the mouse data set within 1.5-fold of the data points. Also, two examples showing the utility of the PBPK model supplement the information regarding the internal dose that caused the health effects observed during these studies. Although this version of the PBPK model expressly describes γ-HBCD, more efforts are needed to clarify and improve the model to discriminate between the α, β, and γ stereoisomers.
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Affiliation(s)
- Claude Emond
- BioSimulation Consulting Inc., Newark, DE, USA; School of Public Health, Department of Environmental and Occupational Health, University of Montreal, Quebec, Canada.
| | - Michael J DeVito
- National Institute of Environmental Health Sciences, National Toxicology Program, Research Triangle Park, NC, USA
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Gillera SEA, Marinello WP, Cao KT, Horman BM, Stapleton HM, Patisaul HB. Sex-specific Disruption of the Prairie Vole Hypothalamus by Developmental Exposure to a Flame Retardant Mixture. Endocrinology 2021; 162:6285199. [PMID: 34038511 PMCID: PMC8571712 DOI: 10.1210/endocr/bqab100] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Indexed: 02/07/2023]
Abstract
Prevalence of neurodevelopmental disorders (NDDs) with social deficits is conspicuously rising, particularly in boys. Flame retardants (FRs) have long been associated with increased risk, and prior work by us and others in multiple species has shown that developmental exposure to the common FR mixture Firemaster 550 (FM 550) sex-specifically alters socioemotional behaviors including anxiety and pair bond formation. In rats, FRs have also been shown to impair aspects of osmoregulation. Because vasopressin (AVP) plays a role in both socioemotional behavior and osmotic balance we hypothesized that AVP and its related nonapeptide oxytocin (OT) would be vulnerable to developmental FM 550 exposure. We used the prairie vole (Microtus ochrogaste) to test this because it is spontaneously prosocial. Using siblings of prairie voles used in a prior study that assessed behavioral deficits resulting from developmental FM 550 exposure across 3 doses, here we tested the hypothesis that FM 550 sex-specifically alters AVP and OT neuronal populations in critical nuclei, such as the paraventricular nucleus (PVN), that coordinate those behaviors, as well as related dopaminergic (determined by tyrosine hydroxylase (TH) immunolabeling) populations. Exposed females had fewer AVP neurons in the anterior PVN and more A13 TH neurons in the zona incerta than controls. By contrast, in FM 550 males, A13 TH neuron numbers in the zona incerta were decreased but only in 1 dose group. These results expand on previous work showing evidence of endocrine disruption of OT/AVP pathways, including to subpopulations of PVN AVP neurons that coordinate osmoregulatory functions in the periphery.
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Affiliation(s)
| | - William P Marinello
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, USA
| | - Kevin T Cao
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, USA
| | - Brian M Horman
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, USA
| | - Heather M Stapleton
- Nicholas School of the Environment, Levine Science Research Center, Duke University, Durham, NC 27710, USA
| | - Heather B Patisaul
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, USA
- Center for Human Health and the Environment, NC State University, Raleigh NC 27695, USA
- Correspondence: Heather B Patisaul, Professor of Biological Sciences, NC State University, 127 David Clark Labs, Raleigh, NC 27695, USA. E-mail:
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Renner H, Becker KJ, Kagermeier TE, Grabos M, Eliat F, Günther P, Schöler HR, Bruder JM. Cell-Type-Specific High Throughput Toxicity Testing in Human Midbrain Organoids. Front Mol Neurosci 2021; 14:715054. [PMID: 34335182 PMCID: PMC8321240 DOI: 10.3389/fnmol.2021.715054] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 06/23/2021] [Indexed: 12/12/2022] Open
Abstract
Toxicity testing is a crucial step in the development and approval of chemical compounds for human contact and consumption. However, existing model systems often fall short in their prediction of human toxicity in vivo because they may not sufficiently recapitulate human physiology. The complexity of three-dimensional (3D) human organ-like cell culture systems ("organoids") can generate potentially more relevant models of human physiology and disease, including toxicity predictions. However, so far, the inherent biological heterogeneity and cumbersome generation and analysis of organoids has rendered efficient, unbiased, high throughput evaluation of toxic effects in these systems challenging. Recent advances in both standardization and quantitative fluorescent imaging enabled us to dissect the toxicities of compound exposure to separate cellular subpopulations within human organoids at the single-cell level in a framework that is compatible with high throughput approaches. Screening a library of 84 compounds in standardized human automated midbrain organoids (AMOs) generated from two independent cell lines correctly recognized known nigrostriatal toxicants. This approach further identified the flame retardant 3,3',5,5'-tetrabromobisphenol A (TBBPA) as a selective toxicant for dopaminergic neurons in the context of human midbrain-like tissues for the first time. Results were verified with high reproducibility in more detailed dose-response experiments. Further, we demonstrate higher sensitivity in 3D AMOs than in 2D cultures to the known neurotoxic effects of the pesticide lindane. Overall, the automated nature of our workflow is freely scalable and demonstrates the feasibility of quantitatively assessing cell-type-specific toxicity in human organoids in vitro.
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Affiliation(s)
- Henrik Renner
- Department for Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Katharina J Becker
- Department for Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany.,Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Theresa E Kagermeier
- Department for Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany.,Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Martha Grabos
- Department for Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Farsam Eliat
- Department for Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany.,Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Patrick Günther
- Department for Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany.,Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Hans R Schöler
- Department for Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Jan M Bruder
- Department for Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
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Harris B, Abou-Elwafa Abdallah M. Exploring variations of hexabromocyclododecane concentrations in riverine sediments along the River Medway, UK. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:776-785. [PMID: 33982722 DOI: 10.1039/d1em00102g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Surface riverine sediment samples were collected along the course of the River Medway, UK, between Yalding and the mouth of the estuary at 40 different sites. The samples were then analysed for hexabromocyclododecane (HBCDD) concentrations using a liquid chromatography system coupled to a high-resolution, accurate mass Orbitrap™ mass spectrometer. After normalisation to the sediment organic carbon (OC) content, average ΣHBCDD was 270 ng g-1 OC with a maximum concentration of 1006 ng g-1 OC. Spatial trend analysis revealed that industrial and residential land uses have significantly influenced HBCDD concentrations and profiles in riverine sediments. Higher concentrations of ΣHBCDD were found in sites near construction and maritime port locations, and these included freight ports, new builds and demolition sites. The HBCDD isomer profile reflected that of the commercial mixture with a comparatively high γ-HBCDD to α-HBCDD and β-HBCDD. The isomer profiles of sites located near construction activities indicate recent pollution events, with increased γ-HBCDD and decreased α-HBCDD compared to the study area's average profile. HBCDD isomer concentrations also indicated that the non-tidal portions of the river caused by locks showed a profile that was typical of older HBCDD contamination, indicating a possible sediment and HBCDD trap.
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Affiliation(s)
- Benjamin Harris
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
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Schrenk D, Bignami M, Bodin L, Chipman JK, del Mazo J, Grasl‐Kraupp B, Hogstrand C, Hoogenboom L(R, Leblanc J, Nebbia CS, Nielsen E, Ntzani E, Petersen A, Sand S, Schwerdtle T, Wallace H, Benford D, Fürst P, Rose M, Ioannidou S, Nikolič M, Bordajandi LR, Vleminckx C. Update of the risk assessment of hexabromocyclododecanes (HBCDDs) in food. EFSA J 2021; 19:e06421. [PMID: 33732387 PMCID: PMC7938899 DOI: 10.2903/j.efsa.2021.6421] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The European Commission asked EFSA to update its 2011 risk assessment on hexabromocyclododecanes (HBCDDs) in food. HBCDDs, predominantly mixtures of the stereoisomers α-, β- and γ-HBCDD, were widely used additive flame retardants. Concern has been raised because of the occurrence of HBCDDs in the environment, food and in humans. Main targets for toxicity are neurodevelopment, the liver, thyroid hormone homeostasis and the reproductive and immune systems. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour in mice can be considered the critical effects. Based on effects on spontaneous behaviour in mice, the Panel identified a lowest observed adverse effect level (LOAEL) of 0.9 mg/kg body weight (bw) as the Reference Point, corresponding to a body burden of 0.75 mg/kg bw. The chronic intake that would lead to the same body burden in humans was calculated to be 2.35 μg/kg bw per day. The derivation of a health-based guidance value (HBGV) was not considered appropriate. Instead, the margin of exposure (MOE) approach was applied to assess possible health concerns. Over 6,000 analytical results for HBCDDs in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary LB exposure to HBCDDs were fish meat, eggs, livestock meat and poultry. The CONTAM Panel concluded that the resulting MOE values support the conclusion that current dietary exposure to HBCDDs across European countries does not raise a health concern. An exception is breastfed infants with high milk consumption, for which the lowest MOE values may raise a health concern.
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Black CA, Bucher ML, Bradner JM, Jonas L, Igarza K, Miller GW. Assessing Vesicular Monoamine Transport and Toxicity Using Fluorescent False Neurotransmitters. Chem Res Toxicol 2020; 34:1256-1264. [PMID: 33378168 DOI: 10.1021/acs.chemrestox.0c00380] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Impairments in the vesicular packaging of dopamine result in an accumulation of dopamine in the cytosol. Cytosolic dopamine is vulnerable to two metabolic processes-enzymatic catabolism and enzymatic- or auto-oxidation-that form toxic metabolites and generate reactive oxygen species. Alterations in the expression or activity of the vesicular monoamine transporter 2 (VMAT2), which transports monoamines such as dopamine from the cytosol into the synaptic vesicle, result in dysregulated dopamine packaging. Here, we developed a series of assays using the fluorescent false neurotransmitter 206 (FFN206) to visualize VMAT2-mediated vesicular packaging at baseline and following pharmacological and toxicological manipulations. As a proof of principle, we observed a significant reduction in vesicular FFN206 packaging after treatment with the VMAT2 inhibitors reserpine (IC50: 73.1 nM), tetrabenazine (IC50: 30.4 nM), methamphetamine (IC50: 2.4 μM), and methylphenidate (IC50: 94.3 μM). We then applied the assay to investigate the consequences on vesicular packaging by environmental toxicants including the pesticides paraquat, rotenone, and chlorpyrifos, as well as the halogenated compounds unichlor, perfluorooctanesulfonic acid, Paroil, Aroclor 1260, and hexabromocyclododecane. Several of the environmental toxicants showed minor impairment of the vesicular FFN206 loading, suggesting that the toxicants are weak VMAT2 inhibitors at the concentrations tested. The assay presented here can be applied to investigate the effect of additional pharmacological compounds and environmental toxicants on vesicular function, which will provide insight into how exposures to such factors are involved in the pathogenesis of monoaminergic diseases such as Parkinson's disease, and the assay can be used to identify pharmacological agents that influence VMAT2 activity.
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Affiliation(s)
- Carlie A Black
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia 30322, United States
| | - Meghan L Bucher
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, United States
| | - Joshua M Bradner
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, United States
| | - Lauren Jonas
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia 30322, United States
| | - Kenny Igarza
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia 30322, United States
| | - Gary W Miller
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, United States
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Agarwal P, Brockman JD, Wang Y, Schneider JA, Morris MC. Brain Bromine Levels Associated with Alzheimer's Disease Neuropathology. J Alzheimers Dis 2020; 73:327-332. [PMID: 31771054 PMCID: PMC10964729 DOI: 10.3233/jad-190646] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Bromine is a naturally occurring element that is widely present in the human environment in various chemical forms primarily as flame retardants, pesticides, and water treatments. OBJECTIVE In this exploratory study, we investigated the association of brain bromine concentrations on Alzheimer's disease (AD) neuropathology, cerebral infarcts, and Lewy bodies. METHODS The study was conducted in 215 deceased participants of the Memory and Aging Project, a clinical-pathologic cohort study. Brain bromine levels were measured using instrumental neutron activation analysis. Multiple brain regions were assessed for diffuse and neuritic plaques, neurofibrillary tangles, cerebral macro-and microinfarcts, and Lewy bodies. Standardized measures of AD pathology (Braak, CERAD, NIA-Reagan, global AD pathology) were computed. RESULTS In linear regression models, the higher brain bromine levels were associated with more AD neuropathology (Braak (p trend = 0.01); CERAD (p trend = 0.02); NIA-Reagan (p trend = 0.02). CONCLUSION Bromine accumulation in the brain is associated with higher level of AD neuropathology. The potential deleterious effects of this element on AD need further exploration.
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Affiliation(s)
- Puja Agarwal
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL, USA
| | | | - Yamin Wang
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Julie A. Schneider
- Rush Alzheimer’s Disease Center and Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Martha C. Morris
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL, USA
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Shi X, Zha J, Wen B, Zhang S. Diastereoisomer-specific neurotoxicity of hexabromocyclododecane in human SH-SY5Y neuroblastoma cells. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 686:893-902. [PMID: 31200309 DOI: 10.1016/j.scitotenv.2019.06.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/29/2019] [Accepted: 06/01/2019] [Indexed: 06/09/2023]
Abstract
Hexabromocyclododecane (HBCD) is a widely applied brominated flame retardant (BFR) and is regarded as a persistent organic pollutant. It has been found in human tissues and has the potential to cause neurological disorders. However, our understanding of HBCD neurotoxicity at the diastereoisomer level remains lacking. Here, we investigated the neurotoxicity of three HBCD diastereoisomers, i.e., α-, β-, and γ-HBCD, in SH-SY5Y human neuroblastoma cells. Results showed that the HBCD diastereoisomers decreased cell viability, increased lactate dehydrogenase (LDH) release, and impaired cytoskeleton development. Typical morphological features and apoptosis rates showed that the HBCD diastereoisomers induced SH-SY5Y cell apoptosis. The expression levels of several cell apoptosis-related genes and proteins, including Bax, caspase-3, caspase-9, cytochrome c, Bcl-2, and X-linked inhibitor of apoptosis (XIAP), as well as the cell cycle arrest, DNA damage, adenosine triphosphate (ATP) consumption, reactive oxygen species (ROS) levels, and intracellular calcium ion (Ca2+) levels, were examined. Results showed that the HBCD diastereoisomer neurotoxicity was ranked β-HBCD > γ-HBCD > α-HBCD. The cell apoptosis and caspase expression levels of the three HBCD diastereoisomers followed the same order, suggesting that caspase-dependent apoptosis may be one mechanism responsible for the structure-selective HBCD diastereoisomer neurotoxicity. The levels of intracellular Ca2+ and ROS increased significantly. The ROS levels were ordered β-HBCD > γ-HBCD > α-HBCD, whereas those of intracellular Ca2+ were γ-HBCD > β-HBCD > α-HBCD. Thus, ROS may be a key factor regulating the neurotoxicity of HBCD diastereoisomers. To the best of our knowledge, this is the first study to report on the diastereoisomer-specific toxicity of HBCD in human neural cells and on the possible mechanisms responsible for the selective neurotoxicity of HBCD diastereoisomers.
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Affiliation(s)
- Xiaoli Shi
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinmiao Zha
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bei Wen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Shuzhen Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Drage DS, Harden FA, Jeffery T, Mueller JF, Hobson P, Toms LML. Human biomonitoring in Australian children: Brominated flame retardants decrease from 2006 to 2015. ENVIRONMENT INTERNATIONAL 2019; 122:363-368. [PMID: 30497797 DOI: 10.1016/j.envint.2018.11.044] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 06/09/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD) were used intensively as flame retardants, worldwide. They have been detected in human serum samples and PBDEs have been found to be elevated in young children. Commercial Penta- and Octa-PBDE mixtures were banned in Australia in 2005, while HBCDD was banned worldwide in 2013. We investigated PBDE and HBCDD concentrations in serum collected from young children. We also investigated temporal trends in PBDE concentration 10 years after their Australian ban. Surplus human blood serum samples were collected through a pathology clinic (n = 800), in 2014/15, stratified by age (0-6, 6-12, 12-18, 18-24, 24-30, 30-36, 36-42, 42-48, 48-54 and 54-60 months) and sex and pooled for analysis of PBDEs (BDEs -28, -47, -99, -100, -153, -154, -183) and HBCDD. In 2014/15, the geometric mean concentration of the sum of all PBDEs measured (ΣPBDEs) was 4.5 ng/g lipid (median: 4.6 ng/g lipid, range: 0.88-26 ng/g lipid). A positive association between BDE-47 concentration and age was observed (R = 0.41, p = 0.008), however there were no trends between other PBDE congeners or HBCDD and age. There were no significant differences between genders for PBDEs (t-test, p = 0.802) or HBCDD (t-test, p = 0.740).The highest concentrations observed were in pools from the females 30-36 month (26 ng/g lipid) and Males 6-12 month (21 ng/g lipid) categories. BDEs -47 and -99 were the predominant congeners with a combined average contribution of 75% of ΣPBDEs. PBDEs showed a significant reduction in children aged 0-4 years over an eight year period. In 2014/15, the mean (range) concentration of BDE-47 is 2.8 (0.23 to 11) ng/g lipid compared to pools in 2006/07 at 19 (3-55) ng/g lipid (p < 0.0001) and for BDE-153 is 0.73 (<0.1 = -2.9) ng/g lipid compared to pools in 2006/07 at 4.7 (2-10) ng/g lipid (p < 0.0001). HBCDD concentrations were lower than PBDEs with a mean concentration of 0.45 ng/g lipid. There were no temporal trends observed for HBCDD when compared to samples collected in 2012. The dominant stereoisomer was α-HBCDD (mean = 0.38 ng/g lipid) with an average contribution of 65% towards ΣHBCDD. Levels of PBDEs in young Australian children have significantly decreased since the bans of commercial Penta- and Octa-BDE in 2005. There has been no observed decrease in HBCDD levels in Australian children since its ban in 2012.
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Affiliation(s)
- Daniel S Drage
- School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston B15 2TT, UK; Queensland Alliance of Environmental Sciences, University of Queensland, 39 Kessels Road, Coopers Plains, Australia.
| | | | - Tomas Jeffery
- School of Public Health and Social Work and Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, Brisbane, Australia
| | - Jochen F Mueller
- Queensland Alliance of Environmental Sciences, University of Queensland, 39 Kessels Road, Coopers Plains, Australia
| | - Peter Hobson
- Sullivan and Nicolaides Pathology, Taringa, Australia
| | - Leisa-Maree L Toms
- School of Public Health and Social Work and Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, Brisbane, Australia
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Parallel in vivo and in vitro transcriptomics analysis reveals calcium and zinc signalling in the brain as sensitive targets of HBCD neurotoxicity. Arch Toxicol 2017; 92:1189-1203. [PMID: 29177809 PMCID: PMC5866835 DOI: 10.1007/s00204-017-2119-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 09/18/2017] [Indexed: 11/04/2022]
Abstract
Hexabromocyclododecane (HBCD) is a brominated flame retardant (BFR) that accumulates in humans and affects the nervous system. To elucidate the mechanisms of HBCD neurotoxicity, we used transcriptomic profiling in brains of female mice exposed through their diet to HBCD (199 mg/kg body weight per day) for 28 days and compared with those of neuronal N2A and NSC-19 cell lines exposed to 1 or 2 µM HBCD. Similar pathways and functions were affected both in vivo and in vitro, including Ca2+ and Zn2+ signalling, glutamatergic neuron activity, apoptosis, and oxidative stress. Release of cytosolic free Zn2+ by HBCD was confirmed in N2A cells. This Zn2+ release was partially quenched by the antioxidant N-acetyl cysteine indicating that, in accordance with transcriptomic analysis, free radical formation is involved in HBCD toxicity. To investigate the effects of HBCD in excitable cells, we isolated mouse hippocampal neurons and monitored Ca2+ signalling triggered by extracellular glutamate or zinc, which are co-released pre-synaptically to trigger postsynaptic signalling. In control cells application of zinc or glutamate triggered a rapid rise of intracellular [Ca2+]. Treatment of the cultures with 1 µM of HBCD was sufficient to reduce the glutamate-dependent Ca2+ signal by 50%. The effect of HBCD on zinc-dependent Ca2+ signalling was even more pronounced, resulting in the reduction of the Ca2+ signal with 86% inhibition at 1 µM HBCD. Our results show that low concentrations of HBCD affect neural signalling in mouse brain acting through dysregulation of Ca2+ and Zn2+ homeostasis.
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Pham-Lake C, Aronoff EB, Camp CR, Vester A, Peters SJ, Caudle WM. Impairment in the mesohippocampal dopamine circuit following exposure to the brominated flame retardant, HBCDD. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2017; 50:167-174. [PMID: 28214749 PMCID: PMC5382642 DOI: 10.1016/j.etap.2017.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 02/03/2017] [Indexed: 06/06/2023]
Abstract
Many chemicals have been used to increase the safety of consumer products by reducing their flammability and risk for ignition. Recent focus on brominated flame retardants, such as polybrominated diphenyl ethers (PBDEs) has shown them to contribute to neurobehavioral deficits in children, including learning and memory. As the manufacture and use of PBDEs have been reduced, replacement chemicals, such as hexabromocyclododecane (HBCDD) have been substituted. Our current study evaluated the neurotoxicity of HBCDD, concentrating on dopaminergic innervation to the hippocampus. Using an in vivo model, we exposed male mice to HBCDD and then assessed alterations to the dopamine synapse 6 weeks later. These exposures elicited significant reductions in presynaptic dopaminergic proteins, including TH, COMT, MAO-B, DAT, VMAT2, and alpha-synuclein. In contrast, postsynaptic dopamine receptors were not impaired. These findings suggest that the mesohippocampal dopamine circuit is vulnerable to HBCDD and the dopamine terminal may be a selective target for alteration.
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Affiliation(s)
- Camille Pham-Lake
- Department of Environmental Health, Rollins School of Public Health Emory University, Atlanta, GA 30322-3090, USA
| | - Elizabeth B Aronoff
- Department of Environmental Health, Rollins School of Public Health Emory University, Atlanta, GA 30322-3090, USA
| | - Chad R Camp
- Department of Environmental Health, Rollins School of Public Health Emory University, Atlanta, GA 30322-3090, USA
| | - Aimee Vester
- Department of Environmental Health, Rollins School of Public Health Emory University, Atlanta, GA 30322-3090, USA
| | - Sam J Peters
- Department of Environmental Health, Rollins School of Public Health Emory University, Atlanta, GA 30322-3090, USA
| | - W Michael Caudle
- Department of Environmental Health, Rollins School of Public Health Emory University, Atlanta, GA 30322-3090, USA; Center for Neurodegenerative Disease, School of Medicine, Emory University Atlanta, GA 30322-3090, USA.
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Drage DS, Mueller JF, Hobson P, Harden FA, Toms LML. Demographic and temporal trends of hexabromocyclododecanes (HBCDD) in an Australian population. ENVIRONMENTAL RESEARCH 2017; 152:192-198. [PMID: 27792943 DOI: 10.1016/j.envres.2016.10.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 10/04/2016] [Accepted: 10/17/2016] [Indexed: 06/06/2023]
Abstract
Hexabromocyclododecanes (HBCDD) were measured in 67 pooled serum samples collected between 2002 and 2015 in South East Queensland, Australia. These data are the first report of HBCDD in Australian human serum. Temporal and demographic (age and gender) trends were investigated. HBCDD were detected in measurable concentrations in 69% of samples. The average ∑HBCDD concentration was 3.1ng/g lipid, whilst the range was <0.5 to 36ng/g lipid. α-HBCDD was the dominant stereoisomer making up an average of 60% of ∑HBCDD. The remainder was made up by γ-HBCDD. In contrast to another group of brominated flame retardants (BFRs, (polybrominated diphenyl ethers (PBDEs)), HBCDD were found in the lowest concentrations in pools from children aged 0-4 years. This could be attributed to differences in exposure, usage, and/ or the much lower half-life of HBCDD in the human body compared to PBDEs. HBCDD concentrations appear to be significantly higher in females than in males, however the reasons for this are unclear.
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Affiliation(s)
- Daniel S Drage
- National Research Centre for Environmental Toxicology, The University of Queensland, 39 Kessels Road, Coopers Plains, Queensland 4108, Australia.
| | - Jochen F Mueller
- National Research Centre for Environmental Toxicology, The University of Queensland, 39 Kessels Road, Coopers Plains, Queensland 4108, Australia
| | - Peter Hobson
- Sullivan and Nicolaides Pathology, Taringa, Australia
| | - Fiona A Harden
- School of Public Health and Social Work and Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, Brisbane, Australia
| | - Leisa-Maree L Toms
- School of Public Health and Social Work and Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, Brisbane, Australia
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Patel R, Bradner JM, Stout KA, Caudle WM. Alteration to Dopaminergic Synapses Following Exposure to Perfluorooctane Sulfonate (PFOS), in Vitro and in Vivo. Med Sci (Basel) 2016; 4:medsci4030013. [PMID: 29083377 PMCID: PMC5635798 DOI: 10.3390/medsci4030013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 08/04/2016] [Accepted: 08/09/2016] [Indexed: 12/30/2022] Open
Abstract
Our understanding of the contribution exposure to environmental toxicants has on neurological disease continues to evolve. Of these, Parkinson’s disease (PD) has been shown to have a strong environmental component to its etiopathogenesis. However, work is still needed to identify and characterize environmental chemicals that could alter the expression and function of the nigrostriatal dopamine system. Of particular interest is the neurotoxicological effect of perfluorinated compounds, such as perfluorooctane sulfonate (PFOS), which has been demonstrated to alter aspects of dopamine signaling. Using in vitro approaches, we have elaborated these initial findings to demonstrate the neurotoxicity of PFOS to the SH-SY5Y neuroblastoma cell line and dopaminergic primary cultured neurons. Using an in vivo model, we did not observe a deficit to dopaminergic terminals in the striatum of mice exposed to 10 mg/kg PFOS for 14 days. However, subsequent exposure to the selective dopaminergic neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) significantly reduced the expression of dopamine transporter (DAT) and tyrosine hydroxylase (TH), and resulted in an even greater reduction in DAT expression in animals previously exposed to PFOS. These findings suggest that PFOS is neurotoxic to the nigrostriatal dopamine circuit and this neurotoxicity could prime the dopamine terminal to more extensive damage following additional toxicological insults.
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Affiliation(s)
- Rahul Patel
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
| | - Joshua M Bradner
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
- Center for Neurodegenerative Disease, School of Medicine, Emory University, Atlanta, GA 30322, USA.
| | - Kristen A Stout
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
- Center for Neurodegenerative Disease, School of Medicine, Emory University, Atlanta, GA 30322, USA.
| | - William Michael Caudle
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
- Center for Neurodegenerative Disease, School of Medicine, Emory University, Atlanta, GA 30322, USA.
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Hendriks HS, Westerink RH. Neurotoxicity and risk assessment of brominated and alternative flame retardants. Neurotoxicol Teratol 2015; 52:248-69. [DOI: 10.1016/j.ntt.2015.09.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 09/01/2015] [Accepted: 09/01/2015] [Indexed: 11/29/2022]
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