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Beausoleil C, Thébault A, Andersson P, Cabaton NJ, Ermler S, Fromenty B, Garoche C, Griffin JL, Hoffmann S, Kamstra JH, Kubickova B, Lenters V, Kos VM, Poupin N, Remy S, Sapounidou M, Zalko D, Legler J, Jacobs MN, Rousselle C. Weight of evidence evaluation of the metabolism disrupting effects of triphenyl phosphate using an expert knowledge elicitation approach. Toxicol Appl Pharmacol 2024; 489:116995. [PMID: 38862081 DOI: 10.1016/j.taap.2024.116995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 06/05/2024] [Accepted: 06/07/2024] [Indexed: 06/13/2024]
Abstract
Identification of Endocrine-Disrupting Chemicals (EDCs) in a regulatory context requires a high level of evidence. However, lines of evidence (e.g. human, in vivo, in vitro or in silico) are heterogeneous and incomplete for quantifying evidence of the adverse effects and mechanisms involved. To date, for the regulatory appraisal of metabolism-disrupting chemicals (MDCs), no harmonised guidance to assess the weight of evidence has been developed at the EU or international level. To explore how to develop this, we applied a formal Expert Knowledge Elicitation (EKE) approach within the European GOLIATH project. EKE captures expert judgment in a quantitative manner and provides an estimate of uncertainty of the final opinion. As a proof of principle, we selected one suspected MDC -triphenyl phosphate (TPP) - based on its related adverse endpoints (obesity/adipogenicity) relevant to metabolic disruption and a putative Molecular Initiating Event (MIE): activation of peroxisome proliferator activated receptor gamma (PPARγ). We conducted a systematic literature review and assessed the quality of the lines of evidence with two independent groups of experts within GOLIATH, with the objective of categorising the metabolic disruption properties of TPP, by applying an EKE approach. Having followed the entire process separately, both groups arrived at the same conclusion, designating TPP as a "suspected MDC" with an overall quantitative agreement exceeding 85%, indicating robust reproducibility. The EKE method provides to be an important way to bring together scientists with diverse expertise and is recommended for future work in this area.
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Affiliation(s)
- Claire Beausoleil
- French Agency for Food, Environmental and Occupational Health and Safety (Anses), 94701 Maisons-Alfort, France.
| | - Anne Thébault
- French Agency for Food, Environmental and Occupational Health and Safety (Anses), 94701 Maisons-Alfort, France
| | | | - Nicolas J Cabaton
- INRAE. UMR1331 Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UT3, 31027 Toulouse, France
| | - Sibylle Ermler
- Department of Life Sciences, Centre of Genome Engineering and Maintenance, College of Health, Medicine and Life Sciences, Brunel University London, UB8 3PH Uxbridge, United Kingdom
| | - Bernard Fromenty
- INSERM, Univ Rennes, INRAE, Institut NUMECAN (Nutrition Metabolisms and Cancer) UMR_A 1341, UMR_S 1317, F-35000 Rennes, France
| | - Clémentine Garoche
- Institut de Recherche en Cancérologie de Montpellier (IRCM), Inserm U1194, Université Montpellier, Institut Régional du Cancer de Montpellier (ICM), Montpellier, France
| | - Julian L Griffin
- The Rowett Institute, Foresterhill Health Campus, University of Aberdeen, Aberdeen, UK
| | | | - Jorke H Kamstra
- Institute for Risk Assessment Sciences, Department of Population Health Sciences, Utrecht University, Utrecht, the Netherlands
| | - Barbara Kubickova
- Radiation, Chemical and Environmental Hazards (RCE), Department of Toxicology, UK Health Security Agency (UKHSA), Harwell Science and Innovation Campus, Chilton OX11 0RQ, Oxon, United Kingdom
| | - Virissa Lenters
- Institute for Risk Assessment Sciences, Department of Population Health Sciences, Utrecht University, Utrecht, the Netherlands
| | - Vesna Munic Kos
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Nathalie Poupin
- INRAE. UMR1331 Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UT3, 31027 Toulouse, France
| | - Sylvie Remy
- Flemish Institute for Technological Research (VITO), 2400 Mol, Belgium
| | | | - Daniel Zalko
- INRAE. UMR1331 Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UT3, 31027 Toulouse, France
| | - Juliette Legler
- Institute for Risk Assessment Sciences, Department of Population Health Sciences, Utrecht University, Utrecht, the Netherlands
| | - Miriam N Jacobs
- Radiation, Chemical and Environmental Hazards (RCE), Department of Toxicology, UK Health Security Agency (UKHSA), Harwell Science and Innovation Campus, Chilton OX11 0RQ, Oxon, United Kingdom
| | - Christophe Rousselle
- French Agency for Food, Environmental and Occupational Health and Safety (Anses), 94701 Maisons-Alfort, France
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2
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Bui TT, Aasa J, Abass K, Ågerstrand M, Beronius A, Castro M, Escrivá L, Galizia A, Gliga A, Karlsson O, Whaley P, Yost E, Rudén C. Applying a modified systematic review and integrated assessment framework (SYRINA) - a case study on triphenyl phosphate. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2024; 26:380-399. [PMID: 38205707 PMCID: PMC10879963 DOI: 10.1039/d3em00353a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024]
Abstract
This work presents a case study in applying a systematic review framework (SYRINA) to the identification of chemicals as endocrine disruptors. The suitability and performance of the framework is tested with regard to the widely accepted World Health Organization definition of an endocrine disruptor (ED). The endocrine disrupting potential of triphenyl phosphate (TPP), a well-studied flame retardant reported to exhibit various endocrine related effects was assessed. We followed the 7 steps of the SYRINA framework, articulating the research objective via Populations, Exposures, Comparators, Outcomes (PECO) statements, performed literature search and screening, conducted study evaluation, performed data extraction and summarized and integrated the evidence. Overall, 66 studies, consisting of in vivo, in vitro and epidemiological data, were included. We concluded that triphenyl phosphate could be identified as an ED based on metabolic disruption and reproductive function. We found that the tools used in this case study and the optimizations performed on the framework were suitable to assess properties of EDs. A number of challenges and areas for methodological development in systematic appraisal of evidence relating to endocrine disrupting potential were identified; significant time and effort were needed for the analysis of in vitro mechanistic data in this case study, thus increasing the workload and time needed to perform the systematic review process. Further research and development of this framework with regards to grey literature (non-peer-reviewed literature) search, harmonization of study evaluation methods, more consistent evidence integration approaches and a pre-defined method to assess links between adverse effect and endocrine activity are recommended. It would also be advantageous to conduct more case studies for a chemical with less data than TPP.
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Affiliation(s)
- Thuy T Bui
- Department of Environmental Science, Stockholm University, Sweden.
| | | | - Khaled Abass
- Department of Environmental Health Sciences, College of Health Sciences, University of Sharjah, United Arab Emirates
- Sharjah Institute for Medical Research (SIMR), University of Sharjah, United Arab Emirates
- Research Unit of Biomedicine and Internal Medicine, Faculty of Medicine, University of Oulu, Finland
| | | | | | - Mafalda Castro
- Section for Environmental Chemistry and Physics, University of Copenhagen, Denmark
| | - Laura Escrivá
- Laboratory of Food Chemistry and Toxicology, Faculty of Pharmacy, University of Valencia, Spain
| | - Audrey Galizia
- United States Environmental Protection Agency, Center for Public Health and Environmental Assessment, USA
| | - Anda Gliga
- Institute of Environmental Medicine, Karolinska Institutet, Sweden
| | - Oskar Karlsson
- Science for Life Laboratory, Department of Environmental Science, Stockholm University, Sweden
| | - Paul Whaley
- Lancaster Environment Centre, Lancaster University, UK
| | - Erin Yost
- United States Environmental Protection Agency, Center for Public Health and Environmental Assessment, USA
| | - Christina Rudén
- Department of Environmental Science, Stockholm University, Sweden.
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3
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Li Z, Hales BF, Robaire B. Impact of Exposure to a Mixture of Organophosphate Esters on Adrenal Cell Phenotype, Lipidome, and Function. Endocrinology 2024; 165:bqae024. [PMID: 38376928 PMCID: PMC10914377 DOI: 10.1210/endocr/bqae024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 02/13/2024] [Accepted: 02/16/2024] [Indexed: 02/21/2024]
Abstract
Organophosphate esters (OPEs) are used primarily as flame retardants and plasticizers. Previously, we reported that adrenal cells are important targets of individual OPEs. However, real-life exposures are to complex mixtures of these chemicals. To address this, we exposed H295R human adrenal cells to varying dilutions (1/1000K to 1/3K) of a Canadian household dust-based OPE mixture for 48 hours and evaluated effects on phenotypic, lipidomic, and functional parameters. Using a high-content screening approach, we assessed phenotypic markers at mixture concentrations at which there was greater than 70% cell survival; the most striking effect of the OPE mixture was a 2.5-fold increase in the total area of lipid droplets. We then determined the response of specific lipid species to OPE exposures with novel, nontargeted lipidomic analysis of isolated lipid droplets. These data revealed that house dust OPEs induced concentration-dependent alterations in the composition of lipid droplets, particularly affecting the triglyceride, diglyceride, phosphatidylcholine, and cholesterol ester subclasses. The steroid-producing function of adrenal cells in the presence or absence of a steroidogenic stimulus, forskolin, was determined. While the production of 17β-estradiol remained unaffected, a slight decrease in testosterone production was observed after stimulation. Conversely, a 2-fold increase in both basal and stimulated cortisol and aldosterone production was observed. Thus, exposure to a house dust-based mixture of OPEs exerts endocrine-disrupting effects on adrenal cells, highlighting the importance of assessing the effects of environmentally relevant mixtures.
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Affiliation(s)
- Zixuan Li
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Barbara F Hales
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Bernard Robaire
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada
- Department of Obstetrics & Gynecology, McGill University, Montreal, QC, H3G 1Y6, Canada
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Burkhardt P, Palma-Duran SA, Tuck ARR, Norgren K, Li X, Nikiforova V, Griffin JL, Munic Kos V. Environmental chemicals change extracellular lipidome of mature human white adipocytes. CHEMOSPHERE 2024; 349:140852. [PMID: 38048832 DOI: 10.1016/j.chemosphere.2023.140852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 10/25/2023] [Accepted: 11/28/2023] [Indexed: 12/06/2023]
Abstract
Certain environmental chemicals affect the body's energy balance and are known as metabolism disrupting chemicals (MDCs). MDCs have been implicated in the development of metabolic diseases, such as obesity and type 2 diabetes. In contrast to their well-known impact on developing adipocytes, MDC effects leading to altered energy balance and development of insulin resistance in mature white adipocytes, constituents of adult adipose tissue, are largely unclear. Here, we investigated the effects of six well-established environmental MDCs (bisphenol A (BPA), perfluorooctanoic acid (PFOA), triclosan (TCS), p,p-dichlorodiphenyl-dichloroethylene (ppDDE), tributyltin chloride (TBT) and triphenyl phosphate (TPP)) on mature human white adipocytes derived from mesenchymal stem cells in vitro. We aimed to identify biomarkers and sensitive endpoints of their metabolism disrupting effects. While most of the tested exposures had no effect on adipocyte glucose consumption, lipid storage and assessed gene expression endpoints, the highest concentration of triclosan affected the total lipid storage and adipocyte size, as well as glucose consumption and mRNA expression of the glucose transporter GLUT1, leptin and adiponectin. Additionally, an increased expression of adiponectin was observed with TPP and the positive control PPARγ agonist rosiglitazone. In contrast, the lipidomic analysis of the cell culture medium after a 3-day exposure was extremely sensitive and revealed concentration-dependent changes in the extracellular lipidome of adipocytes exposed to nearly all studied chemicals. While some of the extracellular lipidome changes were specific for the MDC used, some effects were found common to several tested chemicals and included increases in lysophosphatidylcholines, glycerophospholipids and ceramides and a decrease in fatty acids, with possible implications in inflammation, lipid and glucose uptake. This study points to early signs of metabolic disruption and likely systemic effects of mature adipocyte exposure to environmental chemicals, as well as to the need to include lipidomic endpoints in the assessment of adverse effects of MDCs.
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Affiliation(s)
- Paula Burkhardt
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Susana Alejandra Palma-Duran
- Metabolomics STP, The Francis Crick Institute, London, UK; Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK; Department of Food Science, Research Center in Food and Development A.C., Hermosillo, Mexico
| | - Astrud R R Tuck
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Kalle Norgren
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Xinyi Li
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Violetta Nikiforova
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Julian L Griffin
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK; The Rowett Institute, University of Aberdeen, Aberdeen, UK
| | - Vesna Munic Kos
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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Tachachartvanich P, Rusit X, Tong J, Mann C, La Merrill MA. Perinatal triphenyl phosphate exposure induces metabolic dysfunctions through the EGFR/ERK/AKT signaling pathway: Mechanistic in vitro and in vivo studies. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 269:115756. [PMID: 38056125 DOI: 10.1016/j.ecoenv.2023.115756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/15/2023] [Accepted: 11/26/2023] [Indexed: 12/08/2023]
Abstract
Triphenyl phosphate (TPhP), a widely used organophosphate-flame retardant, is ubiquitously found in household environments and may adversely affect human health. Evidence indicates that TPhP exposure causes metabolic dysfunctions in vivo; however, the underlying mechanism of such adverse effects has not been comprehensively investigated. Herein, we utilized two in vitro models including mouse and human preadipocytes to delineate adipogenic mechanisms of TPhP. The results revealed that both mouse and human preadipocytes exposed to TPhP concentration-dependently accumulated more fat through a significant upregulation of epidermal growth factor receptor (EGFR). We demonstrated that TPhP significantly promoted adipogenesis through the activation of EGFR/ERK/AKT signaling pathway as evident by a drastic reduction in adipogenesis of preadipocytes cotreated with inhibitors of EGFR and its major effectors. Furthermore, we confirmed the mechanism of TPhP-induced metabolic dysfunctions in vivo. We observed that male mice perinatally exposed to TPhP had a significant increase in adiposity, hepatic triglycerides, insulin resistance, plasma insulin levels, hypotension, and phosphorylated EGFR in gonadal fat. Interestingly, an administration of a potent and selective EGFR inhibitor significantly ameliorated the adverse metabolic effects caused by TPhP. Our findings uncovered a potential mechanism of TPhP-induced metabolic dysfunctions and provided implications on toxic metabolic effects posed by environmental chemicals.
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Affiliation(s)
- Phum Tachachartvanich
- Department of Environmental Toxicology, University of California, Davis 95616, CA, USA; Laboratory of Environmental Toxicology, Chulabhorn Research Institute, Bangkok 10210, Thailand
| | - Xylina Rusit
- Department of Environmental Toxicology, University of California, Davis 95616, CA, USA
| | - Jason Tong
- Department of Environmental Toxicology, University of California, Davis 95616, CA, USA
| | - Chanapa Mann
- Department of Environmental Toxicology, University of California, Davis 95616, CA, USA
| | - Michele A La Merrill
- Department of Environmental Toxicology, University of California, Davis 95616, CA, USA.
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Marinello WP, Gillera SEA, Han Y, Richardson JR, St Armour G, Horman BM, Patisaul HB. Gestational exposure to FireMaster® 550 (FM 550) disrupts the placenta-brain axis in a socially monogamous rodent species, the prairie vole (Microtus ochrogaster). Mol Cell Endocrinol 2023; 576:112041. [PMID: 37562579 PMCID: PMC10795011 DOI: 10.1016/j.mce.2023.112041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/26/2023] [Accepted: 08/06/2023] [Indexed: 08/12/2023]
Abstract
Gestational flame retardant (FR) exposure has been linked to heightened risk of neurodevelopmental disorders, but the mechanisms remain largely unknown. Historically, toxicologists have relied on traditional, inbred rodent models, yet those do not always best model human vulnerability or biological systems, especially social systems. Here we used prairie voles (Microtus ochrogaster), a monogamous and bi-parental rodent, leveraged for decades to decipher the underpinnings of social behaviors, to examine the impact of fetal FR exposure on gene targets in the mid-gestational placenta and fetal brain. We previously established gestational exposure to the commercial mixture Firemaster 550 (FM 550) impairs sociality, particularly in males. FM 550 exposure disrupted placental monoamine production, particularly serotonin, and genes required for axon guidance and cellular respiration in the fetal brains. Effects were dose and sex specific. These data provide insights on the mechanisms by which FRs impair neurodevelopment and later in life social behaviors.
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Affiliation(s)
- William P Marinello
- Department of Biological Sciences, NC State University, Raleigh, NC, 27695, USA
| | | | - Yoonhee Han
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL, 33199, USA
| | - Jason R Richardson
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL, 33199, USA
| | - Genevieve St Armour
- 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 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.
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Schkoda S, Horman B, Witchey SK, Jansson A, Macari S, Patisaul HB. Skeletal effects following developmental flame-retardant exposure are specific to sex and chemical class in the adult Wistar rat. FRONTIERS IN TOXICOLOGY 2023; 5:1216388. [PMID: 37577032 PMCID: PMC10414991 DOI: 10.3389/ftox.2023.1216388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 06/22/2023] [Indexed: 08/15/2023] Open
Abstract
Introduction: Accumulating evidence reveals that endocrine disrupting chemicals (EDCs) can disrupt aspects of metabolic programming, suggesting that skeletal development may be at risk, a possibility that is rarely examined. The commercial flame retardant (FR) mixture, Firemaster 550 (FM 550), has repeatedly been shown to negatively influence metabolic programming, raising concerns that skeletal integrity may consequently be impaired. We have previously shown that gestational and lactational exposure to 1,000 µg FM 550 negatively affected sex-specific skeletal traits in male, but not female, rats assessed at 6 months of age. Whether this outcome is primarily driven by the brominated (BFR) or organophosphate ester (OPFR) portions of the mixture or the effects persist to older ages is unknown. Materials and methods: To address this, in the present study, dams were orally exposed throughout gestation and lactation to either 1,000 μg BFR, 1,000 µg OPFR, or 2,000 µg FM 550. Offspring (n = 8/sex/exposure) were weaned at PND 21 and assessed for femoral cortical and trabecular bone parameters at 8 months of age by high-resolution X-ray micro-computed tomography (micro-CT). Serum levels of serotonin, osteocalcin, alkaline phosphatase, and calcium were quantified. Results: FM 550 affected both sexes, but the females were more appreciably impacted by the OPFRs, while the males were more vulnerable to the BFRs. Conclusion: Although sex specificity was expected due to the sexual dimorphic nature of skeletal physiology, the mechanisms accounting for the male- and female-specific phenotypes remain to be determined. Future work aims to clarify these unresolved issues.
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Affiliation(s)
- Stacy Schkoda
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States
| | - Brian Horman
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States
| | - Shannah K. Witchey
- National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, United States
| | - Anton Jansson
- Analytical Instrumentation Facility, North Carolina State University, Raleigh, NC, United States
| | - Soraia Macari
- Department of Restorative Dentistry, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Heather B. Patisaul
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, United States
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8
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An J, Jiang J, Tang W, Zhong Y, Ren G, Shang Y, Yu Z. Lipid metabolic disturbance induced by triphenyl phosphate and hydroxy metabolite in HepG2 cells. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 262:115160. [PMID: 37356402 DOI: 10.1016/j.ecoenv.2023.115160] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 06/12/2023] [Accepted: 06/17/2023] [Indexed: 06/27/2023]
Abstract
Triphenyl phosphate (TPHP) has been widely used as flame retardants and been detected with increasing frequency in environment. TPHP can transform into mono-hydroxylated phosphate (OH-TPHP) and diester diphenyl phosphate (DPHP) through biotransformation. So far, information on the cytotoxicity and molecular regulatory mechanisms of TPHP metabolites are still limit. This study investigated the adverse effects of TPHP, OH-TPHP, and DPHP in HepG2 cells in terms of cell proliferation, lactate dehydrogenase release, reactive oxygen species generation, and mitochondrial membrane potential. The transcriptomic changes were measured using RNA sequencing, and bioinformatics characteristics including biological functions, signal pathways and protein-protein interaction were analyzed to explore the potential molecular mechanisms. Results displayed that the order of cytotoxicity was OH-TPHP> TPHP> DPHP. The prioritized biological functions changes induced by TPHP and OH-TPHP were correlated with lipid metabolism. Significant lipid accumulation was observed as confirmed by increased total cholesterol and triglycerides contents, and enhanced oil red O staining. Enrichment of PPARα/γ and down-stream genes suggested the participation of PPARs signal pathway in lipid metabolism disorder. In addition, TPHP and OH-TPHP induced endoplasmic reticulum stress (ERS), which was further confirmed by the ERS inhibitor experiment. In general, TPHP and OH-TPHP had obvious cytotoxic effects in HepG2 cells. PPARs signal pathway and endoplasmic reticulum stress may be involved in the lipid metabolism disorder induced by TPHP and OH-TPHP.
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Affiliation(s)
- Jing An
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Jingjing Jiang
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Waner Tang
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Yufang Zhong
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Guofa Ren
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Yu Shang
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Zhiqiang Yu
- State Key Laboratory of Organic Geochemistry, Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China.
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Kuiper JR, Vuong AM, Lanphear BP, Calafat AM, Ospina M, Cecil KM, Xu Y, Yolton K, Kalkwarf HJ, Braun JM, Chen A, Buckley JP. Early life organophosphate ester exposures and bone health at age 12 years: The Health Outcomes and Measures of the Environment (HOME) Study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:158246. [PMID: 36030851 PMCID: PMC9606835 DOI: 10.1016/j.scitotenv.2022.158246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/19/2022] [Accepted: 08/19/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND No human studies have evaluated early life organophosphate ester (OPE) exposures with bone health outcomes, despite evidence of osteotoxicity. OBJECTIVES We assessed associations of urinary OPE metabolites measured across early life with areal bone mineral density (aBMD) and bone mineral content (BMC) at age 12 years. METHODS Among 223 mother-child dyads enrolled in the Health Outcomes and Measures of the Environment (HOME) Study, we quantified concentrations of bis-2-chloroethyl phosphate (BCEP), bis-(1,3-dichloro-2-propyl) (BDCIPP), di-n-butyl phosphate (DnBP), and diphenyl phosphate (DPHP) in urine collected from mothers during pregnancy and children at ages 1, 2, 3, 5, and 8 years. At age 12 years, we performed dual energy x-ray absorptiometry and calculated aBMD and BMC z-scores at six skeletal sites. We estimated overall and sex-stratified BMD/BMC z-score differences per interquartile range (IQR) increase in OPE concentrations at multiple exposure timepoints: gestation (average) and 1-3 (average), 5, and 8 years. RESULTS In adjusted models, overall associations of BCEP and BDCIPP with total hip and 1/3rd distal radius aBMD and BMC varied significantly by exposure timepoint, as did BDCIPP with whole body aBMD. For example, differences (95 % CI) in total hip aBMD z-score per IQR increase in BDCIPP were 0.33 (0.01, 0.64), -0.10 (-0.34, 0.14), -0.18 (-0.40, 0.05), and 0.14 (-0.09, 0.38) for concentrations during gestation and at 1-3, 5, and 8 years, respectively. Overall DnBP and DPHP associations were generally null at all timepoints. We observed sex-specific associations for some timepoints and skeletal sites. For example, an IQR increase in 8-year DPHP was associated with a 0.21 (0.05, 0.38) greater total hip aBMD z-score among females but -0.19 (-0.43, 0.05) lower z-score among males. DISCUSSION Early life OPE exposures may be associated with sex- and exposure period-dependent alterations in early adolescent bone mineral accrual and strength.
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Affiliation(s)
- Jordan R Kuiper
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Ann M Vuong
- Department of Epidemiology and Biostatistics, School of Public Health, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Bruce P Lanphear
- Faculty of Health Sciences, Simon Fraser University, Vancouver, BC, Canada
| | - Antonia M Calafat
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Maria Ospina
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Kim M Cecil
- Department of Radiology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Yingying Xu
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kimberly Yolton
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Heidi J Kalkwarf
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Joseph M Braun
- Department of Epidemiology, Brown University, Providence, RI, USA
| | - Aimin Chen
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Jessie P Buckley
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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Witchey SK, Doyle MG, Fredenburg JD, St Armour G, Horman B, Odenkirk MT, Aylor DL, Baker ES, Patisaul HB. Impacts of Gestational FireMaster 550 Exposure on the Neonatal Cortex Are Sex Specific and Largely Attributable to the Organophosphate Esters. Neuroendocrinology 2022; 113:1262-1282. [PMID: 36075192 PMCID: PMC9992460 DOI: 10.1159/000526959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 08/24/2022] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Flame retardants (FRs) are common bodily and environmental pollutants, creating concern about their potential toxicity. We and others have found that the commercial mixture FireMaster® 550 (FM 550) or its individual brominated (BFR) and organophosphate ester (OPFR) components are potential developmental neurotoxicants. Using Wistar rats, we previously reported that developmental exposure to FM 550 or its component classes produced sex- and compound-specific effects on adult socioemotional behaviors. The underlying mechanisms driving the behavioral phenotypes are unknown. METHODS To further mechanistic understanding, here we conducted transcriptomics in parallel with a novel lipidomics approach using cortical tissues from newborn siblings of the rats in the published behavioral study. Inclusion of lipid composition is significant because it is rarely examined in developmental neurotoxicity studies. Pups were gestationally exposed via oral dosing to the dam to FM 550 or the BFR or OPFR components at environmentally relevant doses. RESULTS The neonatal cortex was highly sexually dimorphic in lipid and transcriptome composition, and males were more significantly impacted by FR exposure. Multiple adverse modes of action for the BFRs and OPFRs on neurodevelopment were identified, with the OPFRs being more disruptive than the BFRs via multiple mechanisms including dysregulation of mitochondrial function and disruption of cholinergic and glutamatergic systems. Disrupted mitochondrial function by environmental factors has been linked to a higher risk of autism spectrum disorders and neurodegenerative disorders. Impacted lipid classes included ceramides, sphingomyelins, and triacylglycerides. Robust ceramide upregulation in the OPFR females could suggest a heightened risk of brain metabolic disease. CONCLUSIONS This study reveals multiple mechanisms by which the components of a common FR mixture are developmentally neurotoxic and that the OPFRs may be the compounds of greatest concern.
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Affiliation(s)
- Shannah K Witchey
- Department of Biological Sciences, NC State University, Raleigh, North Carolina, USA
| | - Michael G Doyle
- Department of Chemistry, NC State University, Raleigh, North Carolina, USA
| | - Jacob D Fredenburg
- Department of Biological Sciences, NC State University, Raleigh, North Carolina, USA
| | - Genevieve St Armour
- Department of Biological Sciences, NC State University, Raleigh, North Carolina, USA
| | - Brian Horman
- Department of Biological Sciences, NC State University, Raleigh, North Carolina, USA
| | - Melanie T Odenkirk
- Department of Chemistry, NC State University, Raleigh, North Carolina, USA
| | - David L Aylor
- Department of Biological Sciences, NC State University, Raleigh, North Carolina, USA
- Center for Human Health and the Environment, NC State University, Raleigh, North Carolina, USA
| | - Erin S Baker
- Department of Chemistry, NC State University, Raleigh, North Carolina, USA
| | - Heather B Patisaul
- Center for Human Health and the Environment, NC State University, Raleigh, North Carolina, USA
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11
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Hong J, Jiang M, Guo L, Lin J, Wang Y, Tang H, Liu X. Prenatal exposure to triphenyl phosphate activated PPARγ in placental trophoblasts and impaired pregnancy outcomes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 301:119039. [PMID: 35192884 DOI: 10.1016/j.envpol.2022.119039] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 02/16/2022] [Accepted: 02/18/2022] [Indexed: 06/14/2023]
Abstract
The health risks of triphenyl phosphate (TPhP) have increased since its widespread application. Using placental trophoblast cell line JEG-3, we demonstrated that TPhP could induce endoplasmic reticulum stress (ERS) and cell apoptosis through PPARγ-mediated lipid metabolism. However, the developmental toxicity of TPhP through the placenta is not known. In this study, prenatal TPhP exposure to mice was investigated. Pregnant mice were orally exposed to TPhP (1 and 5 mg/kg) from embryonic day 0 (E0) until delivery. The results showed that TPhP could accumulate in placenta and impair pregnancy outcomes. After exposure, at E18, placental hormone chorionic gonadotrophin and testosterone levels were significantly decreased, but progesterone and estradiol levels were significantly increased, and placental angiogenesis was activated in the low-dose exposure group. While, in the high-dose exposure group, only estradiol levels were significantly increased. Different with the effect on hormone level or angiogenesis, TPhP significantly increased PPARγ and its regulated lipid transport proteins FABP, FATP, and CD36, and induced lipid accumulation in placental trophoblasts of both low- and high-exposure group. RNA-seq analysis of the placenta identified differentially expressed genes that were mainly involved in the ERS and MAPK signaling pathways. Western blot analysis verified that the protein levels related to ERS stress and apoptosis were significantly increased. To further confirm the role of PPARγ in TPhP mediated placental toxicity, pregnant mice were orally exposed to TPhP (1 mg/kg) or TPhP (1 mg/kg) + GW9662 (PPARγ inhibitor, 2 mg/kg) from E0 until delivery. The results showed that GW9662 could ameliorate the effect of TPhP on placental lipid accumulation, ERS and cell apoptosis, suggesting that PPARγ mediated the placental toxicity of TPhP. Overall, our results indicated that prenatal TPhP exposure impaired pregnancy outcomes, at least partly through PPARγ regulated function of trophoblast.
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Affiliation(s)
- Jiabin Hong
- School of Public Health, Dongguan Key Laboratory of Environmental Medicine, Guangdong Medical University, Guangdong, 523-808, China
| | - Mengzhu Jiang
- School of Public Health, Dongguan Key Laboratory of Environmental Medicine, Guangdong Medical University, Guangdong, 523-808, China
| | - Lihao Guo
- School of Public Health, Dongguan Key Laboratory of Environmental Medicine, Guangdong Medical University, Guangdong, 523-808, China
| | - Juntong Lin
- School of Public Health, Dongguan Key Laboratory of Environmental Medicine, Guangdong Medical University, Guangdong, 523-808, China
| | - Yao Wang
- School of Public Health, Dongguan Key Laboratory of Environmental Medicine, Guangdong Medical University, Guangdong, 523-808, China
| | - Huanwen Tang
- School of Public Health, Dongguan Key Laboratory of Environmental Medicine, Guangdong Medical University, Guangdong, 523-808, China
| | - Xiaoshan Liu
- School of Public Health, Dongguan Key Laboratory of Environmental Medicine, Guangdong Medical University, Guangdong, 523-808, China.
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12
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Vail GM, Walley SN, Yasrebi A, Maeng A, Degroat TJ, Conde KM, Roepke TA. Implications of peroxisome proliferator-activated receptor gamma (PPARY) with the intersection of organophosphate flame retardants and diet-induced obesity in adult mice. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2022; 85:381-396. [PMID: 35000574 PMCID: PMC8897244 DOI: 10.1080/15287394.2021.2023716] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Previously, organophosphate flame retardants (OPFRs) were demonstrated to dysregulate homeostatic parameters of energy regulation within an adult mouse model of diet-induced obesity. Using the same OPFR mixture consisting of 1 mg/kg/day of each triphenyl phosphate, tricresyl phosphate, and tris(1,3-dichloro-2-propyl)phosphate, the current study examined the role of peroxisome proliferator-activated receptor gamma (PPARγ) in OPFR-induced disruption by utilizing mice with brain-specific deletion of PPARγ (PPARγKO) fed either a low-fat diet (LFD) or high-fat diet (HFD). Body weight and composition, feeding behavior, glucose and insulin tolerance, circulating peptide hormones, and expression of hypothalamic genes associated with energy homeostasis were recorded. When fed HFD, the effects of OPFR on body weight and feeding behavior observed in the previous wild-type (WT) study were absent in mice lacking neuronal PPARγ. This posits PPARγ as an important target for eliciting OPFR disruption in a diet-induced obesity model. Interestingly, female PPARγKO mice, but not males, experienced many novel OPFR effects not noted in WT mice, including decreased fat mass, altered feeding behavior and efficiency, improved insulin sensitivity, elevated plasma ghrelin and hypothalamic expression of its receptor. Taken together, these data suggest both direct roles for PPARγ in OPFR disruption of obese mice and indirect sensitization of pathways alternative to PPARγ when neuronal expression is deleted.
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Affiliation(s)
- Gwyndolin M. Vail
- Joint Graduate Program in Toxicology, Rutgers, The State University of New Jersey, Piscataway, NJ. USA
| | - Sabrina N. Walley
- Joint Graduate Program in Toxicology, Rutgers, The State University of New Jersey, Piscataway, NJ. USA
| | - Ali Yasrebi
- Department of Animal Sciences, School of Environmental & Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ. USA
| | - Angela Maeng
- Department of Animal Sciences, School of Environmental & Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ. USA
| | - Thomas J. Degroat
- Graduate Program in Endocrinology and Animal Biosciences, School of Environmental & Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ. USA
| | - Kristie M. Conde
- Graduate Program in Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ. USA
| | - Troy A. Roepke
- Joint Graduate Program in Toxicology, Rutgers, The State University of New Jersey, Piscataway, NJ. USA
- Department of Animal Sciences, School of Environmental & Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ. USA
- Graduate Program in Endocrinology and Animal Biosciences, School of Environmental & Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ. USA
- Graduate Program in Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ. USA
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13
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Völker J, Ashcroft F, Vedøy Å, Zimmermann L, Wagner M. Adipogenic Activity of Chemicals Used in Plastic Consumer Products. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022. [PMID: 35080176 DOI: 10.1101/2021.07.29.454199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Bisphenols and phthalates, chemicals frequently used in plastic products, promote obesity in cell and animal models. However, these well-known metabolism-disrupting chemicals (MDCs) represent only a minute fraction of all compounds found in plastics. To gain a comprehensive understanding of plastics as a source of exposure to MDCs, we characterized the chemicals present in 34 everyday products using nontarget high-resolution mass spectrometry and analyzed their joint adipogenic activities by high-content imaging. We detected 55,300 chemical features and tentatively identified 629 unique compounds, including 11 known MDCs. Importantly, the chemicals extracted from one-third of the products caused murine 3T3-L1 preadipocytes to proliferate, and differentiate into adipocytes, which were larger and contained more triglycerides than those treated with the reference compound rosiglitazone. Because the majority of plastic extracts did not activate the peroxisome proliferator-activated receptor γ and the glucocorticoid receptor, the adipogenic effects are mediated via other mechanisms and, thus, likely to be caused by unknown MDCs. Our study demonstrates that daily-use plastics contain potent mixtures of MDCs and can, therefore, be a relevant yet underestimated environmental factor contributing to obesity.
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Affiliation(s)
- Johannes Völker
- Department of Biology, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Felicity Ashcroft
- Department of Biology, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Åsa Vedøy
- Department of Biology, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Lisa Zimmermann
- Department of Aquatic Ecotoxicology, Goethe University Frankfurt am Main, 60438 Frankfurt am Main, Germany
| | - Martin Wagner
- Department of Biology, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
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14
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Goodchild C, Karouna-Renier NK, Henry PFP, Letcher RJ, Schultz SL, Maddox CM, Bean TG, Peters LE, Palace V, Fernie KJ. Thyroid disruption and oxidative stress in American kestrels following embryonic exposure to the alternative flame retardants, EHTBB and TBPH. ENVIRONMENT INTERNATIONAL 2021; 157:106826. [PMID: 34438233 DOI: 10.1016/j.envint.2021.106826] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 07/18/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Brominated flame retardant chemicals, such as 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTBB) (CAS #: 183658-27-7) and bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH) (CAS #: 26040-51-7), have been detected in avian tissues and eggs from remote regions. Exposure to EHTBB and TBPH has been shown to cause oxidative stress and altered thyroid function in rodents and fish, yet no controlled studies have examined potential adverse effects of exposure in birds. Because flame retardants have been detected in wild raptors, we used American kestrels (Falco sparverius) as a model raptor to determine whether in ovo exposure to EHTBB or TBPH affected growth, hatching success, oxidative stress, or thyroid function. We exposed kestrel embryos to nominal concentrations (10, 50, or 100 ng g-1 egg weight) of EHTBB and TBPH via egg-injection on embryonic day 5. Embryonic exposure (~23 d) to EHTBB increased thyroid gland mass, reduced glandular colloid and total thyroxine (T4) in hatchling males and females, whereas deiodinase enzyme activity increased in males but decreased in females. Hatchlings exposed to TBPH in ovo exhibited reduced colloid and increased oxidative stress. Although exposure to EHTBB and TBPH caused several physiological effects (e.g., heart and brain mass), only exposure to 50 ng g-1 EHTBB appeared to reduce hatching success. Our results suggest these flame retardants may be hazardous for predatory birds. Future research should evaluate long-term survival and fitness consequences in birds exposed to these chemicals.
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Affiliation(s)
- Christopher Goodchild
- U.S. Geological Survey, Eastern Ecological Science Center, Patuxent Research Refuge, Beltsville, MD 20705, USA; Department of Biology, University of Central Oklahoma, Edmond, OK 73034, USA
| | - Natalie K Karouna-Renier
- U.S. Geological Survey, Eastern Ecological Science Center, Patuxent Research Refuge, Beltsville, MD 20705, USA.
| | - Paula F P Henry
- U.S. Geological Survey, Eastern Ecological Science Center, Patuxent Research Refuge, Laurel, MD 20708, USA
| | - Robert J Letcher
- Ecotoxicology & Wildlife Health Division, Science & Technology Branch, Environment & Climate Change Canada, Carleton University, Ottawa, Ontario K1A 0H3, Canada
| | - Sandra L Schultz
- U.S. Geological Survey, Eastern Ecological Science Center, Patuxent Research Refuge, Beltsville, MD 20705, USA
| | - Catherine M Maddox
- U.S. Geological Survey, Eastern Ecological Science Center, Patuxent Research Refuge, Beltsville, MD 20705, USA
| | - Thomas G Bean
- Department of Environmental Science and Technology, University of Maryland, College Park, MD 20740, USA
| | - Lisa E Peters
- Faculty of Science, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Vince Palace
- International Institute of Sustainable Development - Experimental Lakes Area, Winnipeg, Manitoba R3B 0T4, Canada
| | - Kim J Fernie
- Ecotoxicology & Wildlife Health Division, Science & Technology Branch, Environment and Climate Change Canada, Burlington, Ontario L7S 1A1, Canada.
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15
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Jenkins JA, Baudoin BA, Johnson D, Fernie KJ, Stapleton HM, Karouna-Renier NK. Establishment of baseline cytology metrics in nestling American kestrels (Falco sparverius): Immunomodulatory effects of the flame retardant isopropylated triarylphosphate isomers. ENVIRONMENT INTERNATIONAL 2021; 157:106779. [PMID: 34555586 DOI: 10.1016/j.envint.2021.106779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 06/17/2021] [Accepted: 07/14/2021] [Indexed: 06/13/2023]
Abstract
Avian populations must mount effective immune responses upon exposure to environmental stressors such as avian influenza and xenobiotics. Although multiple immune assays have been tested and applied to various avian species, antibody-mediated immune responses in non-model avian species are not commonly reported due to the lack of commercially available species-specific antibodies. The objectives of the present study were to advance methods for studying wild bird immune responses and to apply these to the evaluation of cytological responses after exposure of American kestrels, Falco sparverius, to a commercial flame retardant mixture containing isopropylated triarylphosphate isomers (ITP). Hatchlings were gavaged daily with safflower oil or 1.5 ug/g bw/day of ITP suspended in safflower oil, then bled on days 9, 17, and 21. The ITP treatment group (n = 18) and a subset of controls (Poly I:C treatment group; n = 10) were injected on days 9 and 15 with a synthetic analog of viral double-stranded RNA, polyinosinic:polycytidylic acid (Poly I:C), a toll-like receptor ligand and synthetic viral mimic, and responses compared to a sham injected control group (n = 8). The hypotheses tested whether kestrels showed immunological differences among treatment groups, genetic sex, and/or white blood cell (WBC) subpopulation type over time. A flow cytometry (FCM) gating strategy categorized heterophils (H), lymphocytes (L), and monocytes (M) and their proportions, and measured relative fluorescence in response to anti-chicken CD4 binding. Fluorescent cell surfaces and some granular/vacuolar inclusions were visualized by epifluorescence microscopy. A fourth subpopulation with higher levels of granularity than M but less than H became increasingly apparent with time and was gated along with the H subpopulation; its frequency of occurrence was lowest in the ITP group (P = 0.0023). The percentages of cells differed among treatment groups, days, and sexes (P = 0.0001). For both sexes, percentages of H and L were higher than M in control and Poly I:C. In the ITP group, L percentages were higher than H and M (P = 0.0457), and H and L were higher than M on days 9 and 21 (P = 0.0001). The ratios of H:L and H:WBC, indicators of robust immunity, were also higher on days 9 and 21 than on 17 (P = 0.0079). For each sex, the highest levels of activity measured by FCM geometric means (GEO) of fluorescence (indicative of antibody binding) were observed on day 9 (P = 0.0001 female, and P = 0.0011 male) in H over both L and M (P < 0.0001 for each). In males, GEO of the Poly I:C group was higher than that of the ITP group (P = 0.0374), with no difference observed among females over all days. By using a FCM algorithm for population comparisons of fluorescence to investigate binding within H, the T(x) scores indicated higher fluorescence in control and Poly I:C groups over ITP (P = 0.0001). Unlike chickens, Gallus gallus, which express CD4 primarily on L, kestrels bound the commercial antibody primarily within the gated H subpopulation, suggesting an immunophenotypic difference between taxa, despite a ~60% identity of Falco CD4 amino acid sequences with chicken CD4. The emergent cell subset within the gated H presented dendritic-like cell (DLC) morphological and functional properties, apparently serving as an effector cell. This study adds interpretive context to ecological investigations of infection and of potential immunomodulation by emerging compounds, whereby the early innate responses are mediated by the various cell subsets serving as useful quantitative markers of immunological condition. Data showed that dietary exposure to ITP was immunosuppressive for male and female kestrels over the course of the experiment, reducing DLC frequency compared to the Poly I:C controls. Heterophils and DLC were important in facilitating innate immunological responses.
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Affiliation(s)
- Jill A Jenkins
- U.S. Geological Survey, Wetland and Aquatic Research Center, 700 Cajundome Boulevard, Lafayette, LA 70506, United States.
| | - Brooke A Baudoin
- U.S. Geological Survey, Wetland and Aquatic Research Center, 700 Cajundome Boulevard, Lafayette, LA 70506, United States
| | - Darren Johnson
- Cherokee Nations Technologies under contract to the U.S. Geological Survey, 700 Cajundome Boulevard, Lafayette, LA 70506, United States
| | - Kim J Fernie
- Ecotoxicology & Wildlife Health Division, Environment & Climate Change Canada, 867 Lakeshore Road, Burlington, Ontario L7S 1A1, Canada
| | - Heather M Stapleton
- Duke University, Nicholas School of the Environment, Box 90328, Durham, NC 27708, United States
| | - Natalie K Karouna-Renier
- U.S. Geological Survey, Eastern Ecological Science Center, Patuxent Research Refuge, 308 Center Road, Beltsville, MD 20705, United States
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16
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Negi CK, Bajard L, Kohoutek J, Blaha L. An adverse outcome pathway based in vitro characterization of novel flame retardants-induced hepatic steatosis. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 289:117855. [PMID: 34340181 DOI: 10.1016/j.envpol.2021.117855] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/16/2021] [Accepted: 07/25/2021] [Indexed: 05/22/2023]
Abstract
A wide range of novel replacement flame retardants (nFRs) is consistently detected in increasing concentrations in the environment and human matrices. Evidence suggests that nFRs exposure may be associated with disruption of the endocrine system, which has been linked with the etiology of various metabolic disorders, including nonalcoholic fatty liver disease (NAFLD). NAFLD is a multifactorial disease characterized by the uncontrolled accumulation of fats (lipids) in the hepatocytes and involves multiple-hit pathogenesis, including exposure to occupational and environmental chemicals such as organophosphate flame retardants (OPFRs). In the present study we aimed to investigate the potential mechanisms of the nFRs-induced hepatic steatosis in the human liver cells. In this study, we employed an in vitro bioassay toolbox to assess the key events (KEs) in the proposed adverse outcome pathways (AOP) (s) for hepatic steatosis. We examined nine nFRs using AOP- based in vitro assays measuring KEs such as lipid accumulation, mitochondrial dysfunction, gene expression, and in silico approach to identify the putative molecular initiating events (MIEs). Our findings suggest that several tested OPFRs induced lipid accumulation in human liver cell culture. Tricresyl phosphate (TMPP), triphenyl phosphate (TPHP), tris(1,3-dichloropropyl) phosphate (TDCIPP), and 2-ethylhexyl diphenyl phosphate (EHDPP) induced the highest lipid accumulation by altering the expression of genes encoding hepatic de novo lipogenesis and mitochondrial dysfunction depicted by decreased cellular ATP production. Available in vitro data from ToxCast and in silico molecular docking suggests that pregnane X receptor (PXR) and peroxisome proliferator-activated receptor gamma (PPARγ) could be the molecular targets for the tested nFRs. The study identifies several nFRs, such as TMPP and EHDPP, TPHP, and TDCIPP, as potential risk factor for NAFLD and advances our understanding of the mechanisms involved, demonstrating the utility of an AOP-based strategy for screening and prioritizing chemicals and elucidating the molecular mechanisms of toxicity.
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Affiliation(s)
- Chander K Negi
- Faculty of Science, RECETOX, Masaryk University, Kamenice 5, CZ62500, Brno, Czech Republic
| | - Lola Bajard
- Faculty of Science, RECETOX, Masaryk University, Kamenice 5, CZ62500, Brno, Czech Republic
| | - Jiri Kohoutek
- Faculty of Science, RECETOX, Masaryk University, Kamenice 5, CZ62500, Brno, Czech Republic
| | - Ludek Blaha
- Faculty of Science, RECETOX, Masaryk University, Kamenice 5, CZ62500, Brno, Czech Republic.
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Patisaul HB, Behl M, Birnbaum LS, Blum A, Diamond ML, Rojello Fernández S, Hogberg HT, Kwiatkowski CF, Page JD, Soehl A, Stapleton HM. Beyond Cholinesterase Inhibition: Developmental Neurotoxicity of Organophosphate Ester Flame Retardants and Plasticizers. ENVIRONMENTAL HEALTH PERSPECTIVES 2021; 129:105001. [PMID: 34612677 PMCID: PMC8493874 DOI: 10.1289/ehp9285] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 07/02/2021] [Accepted: 08/11/2021] [Indexed: 05/26/2023]
Abstract
BACKGROUND To date, the toxicity of organophosphate esters has primarily been studied regarding their use as pesticides and their effects on the neurotransmitter acetylcholinesterase (AChE). Currently, flame retardants and plasticizers are the two largest market segments for organophosphate esters and they are found in a wide variety of products, including electronics, building materials, vehicles, furniture, car seats, plastics, and textiles. As a result, organophosphate esters and their metabolites are routinely found in human urine, blood, placental tissue, and breast milk across the globe. It has been asserted that their neurological effects are minimal given that they do not act on AChE in precisely the same way as organophosphate ester pesticides. OBJECTIVES This commentary describes research on the non-AChE neurodevelopmental toxicity of organophosphate esters used as flame retardants and plasticizers (OPEs). Studies in humans, mammalian, nonmammalian, and in vitro models are presented, and relevant neurodevelopmental pathways, including adverse outcome pathways, are described. By highlighting this scientific evidence, we hope to elevate the level of concern for widespread human exposure to these OPEs and to provide recommendations for how to better protect public health. DISCUSSION Collectively, the findings presented demonstrate that OPEs can alter neurodevelopmental processes by interfering with noncholinergic pathways at environmentally relevant doses. Application of a pathways framework indicates several specific mechanisms of action, including perturbation of glutamate and gamma-aminobutyric acid and disruption of the endocrine system. The effects may have implications for the development of cognitive and social skills in children. Our conclusion is that concern is warranted for the developmental neurotoxicity of OPE exposure. We thus describe important considerations for reducing harm and to provide recommendations for government and industry decision makers. https://doi.org/10.1289/EHP9285.
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Affiliation(s)
- Heather B. Patisaul
- College of Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Mamta Behl
- National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
- National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - Linda S. Birnbaum
- National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
- National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
- Nicholas School of the Environment, Duke University, Durham, North Carolina, USA
| | - Arlene Blum
- Green Science Policy Institute, Berkeley, California, USA
- Department of Chemistry, University of California, Berkeley, Berkeley, California, USA
| | | | | | - Helena T. Hogberg
- Center for Alternatives to Animal Testing, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Carol F. Kwiatkowski
- Green Science Policy Institute, Berkeley, California, USA
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Jamie D. Page
- Cancer Prevention & Education Society, Meads House, Leighterton, Tetbury, Gloucestershire, UK
| | - Anna Soehl
- Green Science Policy Institute, Berkeley, California, USA
| | - Heather M. Stapleton
- Nicholas School of the Environment, Duke University, Durham, North Carolina, USA
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18
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Krentzel AA, Kimble LC, Dorris DM, Horman BM, Meitzen J, Patisaul HB. FireMaster® 550 (FM 550) exposure during the perinatal period impacts partner preference behavior and nucleus accumbens core medium spiny neuron electrophysiology in adult male and female prairie voles, Microtus ochrogaster. Horm Behav 2021; 134:105019. [PMID: 34182292 PMCID: PMC8403633 DOI: 10.1016/j.yhbeh.2021.105019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/27/2021] [Accepted: 06/11/2021] [Indexed: 11/23/2022]
Abstract
One of the most widely used flame retardant (FR) mixtures in household products is Firemaster 550 (FM 550). FM 550 leaches from items such as foam-based furniture and infant products, resulting in contamination of the household environment and biota. Previous studies indicate sex-specific behavioral deficits in rodents and zebrafish in response to developmental FM 550 exposure. These deficits include impacts on social and attachment behaviors in a prosocial rodent: the prairie vole (Microtus ochrogaster). The prairie vole is a laboratory-acclimated rodent that exhibits spontaneous attachment behaviors including pair bonding. Here we extend previous work by addressing how developmental exposure to FM 550 impacts pair bonding strength via an extended-time partner preference test, as well as neuron electrophysiological properties in a region implicated in pair bond behavior, the nucleus accumbens (NAcc) core. Dams were exposed to vehicle or 1000 μg of FM 550 via subcutaneous injections throughout gestation, and female and male pups were directly exposed beginning the day after birth until weaning. Pair bond behavior of adult female and male offspring was assessed using a three hour-long partner preference test. Afterwards, acute brain slices of the NAcc core were produced and medium spiny neuron electrophysiological attributes recorded via whole cell patch-clamp. Behavioral impacts were sex-specific. Partner preference behavior was increased in exposed females but decreased in exposed males. Electrophysiological impacts were similar between sexes and specific to attributes related to input resistance. Input resistance was decreased in neurons recorded from both sexes exposed to FM 550 compared to vehicle. This study supports the hypothesis that developmental exposure to FM 550 impacts attachment behaviors and demonstrates a novel FM 550 effect on neural electrophysiology.
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Affiliation(s)
- Amanda A Krentzel
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Laney C Kimble
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - David M Dorris
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Brian M Horman
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - John Meitzen
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC 27695, USA; Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27695, USA.
| | - Heather B Patisaul
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC 27695, USA
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Natural Extracts from White Common Bean (Phaseolus vulgaris L.) Inhibit 3T3-L1 Adipocytes Differentiation. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app11010167] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background: Recent studies have shown that the consumption of common bean (Phaseolus vulgaris L.) foods plays an essential role in the prevention and treatment of obesity. Methods: In this study, different natural extracts that include common bean polyphenol-rich extract (CBP), α-amylase inhibitor-rich extract (α-AIE), and non-starch polysaccharides-rich extract (NSP) were isolated. Their effects on 3T3-L1 adipocytes differentiation were evaluated, respectively. Results: The results showed that CPB reduced the lipid content in the mature adipocytes to 79.29% (150 μg/mL) and 35.13% (300 μg/mL), and α-AIE reduced it to 90.20% (2 mg/mL) and 68.28% (4 mg/mL), while NSP exhibited an auxo-action, suggesting that both CBP and a-AIE inhibited 3T3-L1 adipocytes differentiation. Additionally, CBP significantly suppressed (p < 0.05) the mRNA expression level and the protein expression level of peroxisome proliferator-activated receptor γ (PPARγ), CCAAT-enhancer-binding protein α (C/EBPα), sterol-regulatory element binding proteins 1 c (SREBP-1c), lipoprotein lipase (LPL), and fatty acid binding protein (ap2). Meanwhile, α-AIE only showed significant suppression effects on PPARγ, C/EBPα, and ap2 at the high dose of 4 mg/mL (p < 0.05). Conclusions: These findings indicate that CBP, from white common bean, might be the major component responsible for the inhibitory effects on adipocyte differentiation.
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Selmi-Ruby S, Marín-Sáez J, Fildier A, Buleté A, Abdallah M, Garcia J, Deverchère J, Spinner L, Giroud B, Ibanez S, Granjon T, Bardel C, Puisieux A, Fervers B, Vulliet E, Payen L, Vigneron AM. In Vivo Characterization of the Toxicological Properties of DPhP, One of the Main Degradation Products of Aryl Phosphate Esters. ENVIRONMENTAL HEALTH PERSPECTIVES 2020; 128:127006. [PMID: 33296241 PMCID: PMC7725437 DOI: 10.1289/ehp6826] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 05/31/2023]
Abstract
BACKGROUND Aryl phosphate esters (APEs) are widely used and commonly present in the environment. Health hazards associated with these compounds remain largely unknown and the effects of diphenyl phosphate (DPhP), one of their most frequent derivatives, are poorly characterized. OBJECTIVE Our aim was to investigate whether DPhP per se may represent a more relevant marker of exposure to APEs than direct assessment of their concentration and determine its potential deleterious biological effects in chronically exposed mice. METHODS Conventional animals (FVB mice) were acutely or chronically exposed to relevant doses of DPhP or to triphenyl phosphate (TPhP), one of its main precursors. Both molecules were measured in blood and other tissues by liquid chromatography-mass spectrometry (LC-MS). Effects of chronic DPhP exposure were addressed through liver multi-omics analysis to determine the corresponding metabolic profile. Deep statistical exploration was performed to extract correlated information, guiding further physiological analyses. RESULTS Multi-omics analysis confirmed the existence of biological effects of DPhP, even at a very low dose of 0.1mg/mL in drinking water. Chemical structural homology and pathway mapping demonstrated a clear reduction of the fatty acid catabolic processes centered on acylcarnitine and mitochondrial β-oxidation in mice exposed to DPhP in comparison with those treated with vehicle. An interesting finding was that in mice exposed to DPhP, mRNA, expression of genes involved in lipid catabolic processes and regulated by peroxisome proliferator-activated receptor alpha (PPARα) was lower than that in vehicle-treated mice. Immunohistochemistry analysis showed a specific down-regulation of HMGCS2, a kernel target gene of PPARα. Overall, DPhP absorption disrupted body weight-gain processes. CONCLUSIONS Our results suggest that in mice, the effects of chronic exposure to DPhP, even at a low dose, are not negligible. Fatty acid metabolism in the liver is essential for controlling fast and feast periods, with adverse consequences on the overall physiology. Therefore, the impact of DPhP on circulating fat, cardiovascular pathologies and metabolic disease incidence deserves, in light of our results, further investigations. https://doi.org/10.1289/EHP6826.
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Affiliation(s)
- Samia Selmi-Ruby
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Equipe Labellisée Ligue contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Jesús Marín-Sáez
- Department of Chemistry and Physics, Analytical Chemistry Area, University of Almería, Research Centre for Agricultural and Food Biotechnology (BITAL), Agrifood Campus of International Excellence, Almería, Spain
| | - Aurélie Fildier
- CNRS, Institut des Sciences Analytiques, UMR 5280, Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Audrey Buleté
- CNRS, Institut des Sciences Analytiques, UMR 5280, Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Myriam Abdallah
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Equipe Labellisée Ligue contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Jessica Garcia
- Hospices Civils de Lyon, Centre Hospitalier Lyon–Sud, Biochemistry, Pharmacotoxicology, and Molecular Biology Department, Université de Lyon, Université Claude Bernard Lyon 1, Pierre Bénite, France
| | - Julie Deverchère
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Equipe Labellisée Ligue contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Loïc Spinner
- CNRS, Institut des Sciences Analytiques, UMR 5280, Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Barbara Giroud
- CNRS, Institut des Sciences Analytiques, UMR 5280, Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Sébastien Ibanez
- CNRS, Molecular and Supramolecular Chemistry and Biochemistry Institute ICBMS UMR 5246, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Thierry Granjon
- CNRS, Molecular and Supramolecular Chemistry and Biochemistry Institute ICBMS UMR 5246, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Claire Bardel
- Department of Biostatistics, Hospices Civils de Lyon, Lyon, France
- CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, Université de Lyon, Université Lyon 1, Villeurbanne, France
| | - Alain Puisieux
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Equipe Labellisée Ligue contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Béatrice Fervers
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Equipe Labellisée Ligue contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Emmanuelle Vulliet
- CNRS, Institut des Sciences Analytiques, UMR 5280, Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Léa Payen
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Equipe Labellisée Ligue contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Hospices Civils de Lyon, Centre Hospitalier Lyon–Sud, Biochemistry, Pharmacotoxicology, and Molecular Biology Department, Université de Lyon, Université Claude Bernard Lyon 1, Pierre Bénite, France
| | - Arnaud M. Vigneron
- INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Equipe Labellisée Ligue contre le Cancer, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
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Vail GM, Roepke TA. Organophosphate Flame Retardants Excite Arcuate Melanocortin Circuitry and Increase Neuronal Sensitivity to Ghrelin in Adult Mice. Endocrinology 2020; 161:5910086. [PMID: 32961558 PMCID: PMC7575050 DOI: 10.1210/endocr/bqaa168] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 09/17/2020] [Indexed: 12/28/2022]
Abstract
Organophosphate flame retardants (OPFRs) are a class of chemicals that have become near ubiquitous in the modern environment. While OPFRs provide valuable protection against flammability of household items, they are increasingly implicated as an endocrine disrupting chemical (EDC). We previously reported that exposure to a mixture of OPFRs causes sex-dependent disruptions of energy homeostasis through alterations in ingestive behavior and activity in adult mice. Because feeding behavior and energy expenditure are largely coordinated by the hypothalamus, we hypothesized that OPFR disruption of energy homeostasis may occur through EDC action on melanocortin circuitry within the arcuate nucleus. To this end, we exposed male and female transgenic mice expressing green fluorescent protein in either neuropeptide Y (NPY) or proopiomelanocortin (POMC) neurons to a common mixture of OPFRs (triphenyl phosphate, tricresyl phosphate, and tris(1,3-dichloro-2-propyl)phosphate; each 1 mg/kg bodyweight/day) for 4 weeks. We then electrophysiologically examined neuronal properties using whole-cell patch clamp technique. OPFR exposure depolarized the resting membrane of NPY neurons and dampened a hyperpolarizing K+ current known as the M-current within the same neurons from female mice. These neurons were further demonstrated to have increased sensitivity to ghrelin excitation, which more potently reduced the M-current in OPFR-exposed females. POMC neurons from female mice exhibited elevated baseline excitability and are indicated in receiving greater excitatory synaptic input when exposed to OPFRs. Together, these data support a sex-selective effect of OPFRs to increase neuronal output from the melanocortin circuitry governing feeding behavior and energy expenditure, and give reason for further examination of OPFR impact on human health.
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Affiliation(s)
- Gwyndolin M Vail
- Joint Graduate Program in Toxicology, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Troy A Roepke
- Joint Graduate Program in Toxicology, Rutgers, The State University of New Jersey, Piscataway, New Jersey
- Department of Animal Sciences, School of Environmental & Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey
- Environmental and Occupational Health Science Institute, Rutgers, The State University of New Jersey, Piscataway, New Jersey
- Rutgers Center for Lipid Research, Center for Nutrition, Microbiome, and Health, and New Jersey Institute of Food, Nutrition, and Health, Rutgers, The State University of New Jersey, New Brunswick, New Jersey
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Triphenyl phosphate is a selective PPARγ modulator that does not induce brite adipogenesis in vitro and in vivo. Arch Toxicol 2020; 94:3087-3103. [PMID: 32683515 DOI: 10.1007/s00204-020-02815-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 06/18/2020] [Indexed: 01/08/2023]
Abstract
Triphenyl phosphate (TPhP) is an environmental PPARγ ligand, and growing evidence suggests that it is a metabolic disruptor. We have shown previously that the structurally similar ligand, tributyltin, does not induce brite adipocyte gene expression. Here, using in vivo and in vitro models, we tested the hypothesis that TPhP is a selective PPARγ ligand, which fails to induce brite adipogenesis. C57BL/6 J male mice were fed either a low or very high-fat diet for 13 weeks. From weeks 7-13, mice were injected intraperitoneally, daily, with vehicle, rosiglitazone (Rosi), or TPhP (10 mg/kg). Compared to Rosi, TPhP did not induce expression of browning-related genes (e.g. Elovl3, Cidea, Acaa2, CoxIV) in mature adipocytes isolated from inguinal adipose. To determine if this resulted from an effect directly on the adipocytes, 3T3-L1 cells and primary human preadipocytes were differentiated into adipocytes in the presence of Rosi or TPhP. Rosi, but not TPhP, induced expression of brite adipocyte genes, mitochondrial biogenesis and cellular respiration. Further, Rosi and TPhP-induced distinct proteomes and phosphoproteomes; Rosi enriched more regulatory pathways related to fatty acid oxidation and mitochondrial proteins. We assessed the role of phosphorylation of PPARγ in these differences in 3T3-L1 cells. Only Rosi protected PPARγ from phosphorylation at Ser273. TPhP gained the ability to stimulate brite adipocyte gene expression in the presence of the CDK5 inhibitor and in 3T3-L1 cells expressing alanine at position 273. We conclude that TPhP is a selective PPARγ modulator that fails to protect PPARγ from phosphorylation at ser273.
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23
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Yan H, Hales BF. Effects of Organophosphate Ester Flame Retardants on Endochondral Ossification in Ex Vivo Murine Limb Bud Cultures. Toxicol Sci 2020; 168:420-429. [PMID: 30561715 DOI: 10.1093/toxsci/kfy301] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Phasing out the usage of polybrominated diphenyl ether (PBDE) flame retardants (FRs) in consumer products led to their widespread replacement with organophosphate ester (OPE) FRs, despite scarce safety data. PBDE exposures were associated with the suppression of endochondral ossification but little is known about the effects of OPEs on bones. Here, we used a novel ex vivo murine limb bud culture system to compare the effects of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) with those of several OPEs. Gestation day 13 embryos were collected from transgenic CD1 mice expressing fluorescent markers for the major stages of endochondral ossification: COL2A1-ECFP (chondrogenesis), COL10A1-mCherry (early osteogenesis), and COL1A1-YFP (late osteogenesis). Limbs were excised and cultured for 6 days in the presence of vehicle, BDE-47, or an OPE FR: triphenyl phosphate (TPHP), tert-butylphenyl diphenyl phosphate (BPDP), tris(methylphenyl) phosphate (TMPP), or isopropylated triphenyl phosphate (IPPP). BDE-47 (50 μM) decreased the extent of chondrogenesis in the digits and COL1A1-YFP expression in the radius and ulna relative to control. In comparison, concentrations of ≥1 μM of all 4 OPEs limited chondrogenesis; osteogenesis (both COL10A1-mCherry and COL1A1-YFP fluorescence) was markedly inhibited at concentrations ≥3 μM. The expression of Sox9, the master regulator of chondrogenesis, was altered by BDE-47, TPHP, and BPDP. BDE-47 exposure had minimal impact on the expression of Runx2 and Sp7, which drive osteogenesis, whereas TPHP and BPDP both suppressed the expression of these transcription factors. These data suggest that OPE FRs may be more detrimental to bone formation than their brominated predecessors.
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Affiliation(s)
- Han Yan
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Barbara F Hales
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
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Gillera SEA, Marinello WP, Horman BM, Phillips AL, Ruis MT, Stapleton HM, Reif DM, Patisaul HB. Sex-specific effects of perinatal FireMaster® 550 (FM 550) exposure on socioemotional behavior in prairie voles. Neurotoxicol Teratol 2019; 79:106840. [PMID: 31730801 DOI: 10.1016/j.ntt.2019.106840] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 10/27/2019] [Accepted: 10/28/2019] [Indexed: 01/15/2023]
Abstract
The rapidly rising incidence of neurodevelopmental disorders with social deficits is raising concern that developmental exposure to environmental contaminants may be contributory. Firemaster 550 (FM 550) is one of the most prevalent flame-retardant (FR) mixtures used in foam-based furniture and baby products and contains both brominated and organophosphate components. We and others have published evidence of developmental neurotoxicity and sex specific effects of FM 550 on anxiety-like and exploratory behaviors. Using a prosocial animal model, we investigated the impact of perinatal FM 550 exposure on a range of socioemotional behaviors including anxiety, attachment, and memory. Virtually unknown to toxicologists, but widely used in the behavioral neurosciences, the prairie vole (Microtus ochrogaster) is a uniquely valuable model organism for examining environmental factors on sociality because this species is spontaneously prosocial, biparental, and displays attachment behaviors including pair bonding. Dams were exposed to 0, 500, 1000, or 2000 μg of FM 550 via subcutaneous (sc) injections throughout gestation, and pups were directly exposed beginning the day after birth until weaning. Adult offspring of both sexes were then subjected to multiple tasks including open field, novel object recognition, and partner preference. Effects were dose responsive and sex-specific, with females more greatly affected. Exposure-related outcomes in females included elevated anxiety, decreased social interaction, decreased exploratory motivation, and aversion to novelty. Exposed males also had social deficits, with males in all three dose groups failing to show a partner preference. Our studies demonstrate the utility of the prairie vole for investigating the impact of chemical exposures on social behavior and support the hypothesis that developmental FR exposure impacts the social brain. Future studies will probe the possible mechanisms by which these effects arise.
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Affiliation(s)
| | - William P Marinello
- 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
| | - Allison L Phillips
- Nicholas School of the Environment, Levine Science Research Center, Duke University, Durham, NC 27710, USA
| | - Matthew T Ruis
- Nicholas School of the Environment, Levine Science Research Center, Duke University, Durham, NC 27710, USA
| | - Heather M Stapleton
- Nicholas School of the Environment, Levine Science Research Center, Duke University, Durham, NC 27710, USA
| | - David M Reif
- Center for Human Health and the Environment, NC State University, Raleigh, NC 27695, USA; Bioinformatics Research Center, North Carolina State University, Raleigh, NC 27695, 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.
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Lee MK, Blumberg B. Transgenerational effects of obesogens. Basic Clin Pharmacol Toxicol 2019; 125 Suppl 3:44-57. [PMID: 30801972 PMCID: PMC6708505 DOI: 10.1111/bcpt.13214] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 02/08/2019] [Indexed: 02/06/2023]
Abstract
Obesity and associated disorders are now a global pandemic. The prevailing clinical model for obesity is overconsumption of calorie-dense food and diminished physical activity (the calories in-calories out model). However, this explanation does not account for numerous recent research findings demonstrating that a variety of environmental factors can be superimposed on diet and exercise to influence the development of obesity. The environmental obesogen model proposes that exposure to chemical obesogens during in utero and/or early life can strongly influence later predisposition to obesity. Obesogens are chemicals that inappropriately stimulate adipogenesis and fat storage, in vivo either directly or indirectly. Numerous obesogens have been identified in recent years and some of these elicit transgenerational effects on obesity as well as a variety of health end-points after exposure of pregnant F0 females. Prenatal exposure to environmental obesogens can produce lasting effects on the exposed animals and their offspring to at least the F4 generation. Recent results show that some of these transgenerational effects of obesogen exposure can be carried across the generations via alterations in chromatin structure and accessibility. That some chemicals can have permanent effects on the offspring of exposed animals suggests increased caution in the debate about whether and to what extent exposure to endocrine-disrupting chemicals and obesogens should be regulated.
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Affiliation(s)
- Michelle Kira Lee
- Department of Developmental and Cell Biology, 2011 BioSci
3, University of California, Irvine, CA 926970-2300
| | - Bruce Blumberg
- Department of Developmental and Cell Biology, 2011 BioSci
3, University of California, Irvine, CA 926970-2300
- Department of Pharmaceutical Sciences, University of
California, Irvine
- Dept of Biomedical Engineering, University of California,
Irvine
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26
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Zhang K, Yuan Q, Xie J, Yuan L, Wang Y. PPAR-γ activation increases insulin secretion independent of CASK in INS-1 cells. Acta Biochim Biophys Sin (Shanghai) 2019; 51:715-722. [PMID: 31168600 DOI: 10.1093/abbs/gmz052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Indexed: 01/03/2023] Open
Abstract
Peroxisome proliferator-activated receptor-γ (PPAR-γ) is expressed in pancreatic β cells and is involved in insulin secretion. However, the precise mechanisms remain unclear. Calcium/calmodulin-dependent serine protein kinase (CASK), which plays a vital role in the anchoring of insulin granules on pancreatic β cell membrane, is probably a downstream of the transcription factor PPAR-γ. The aim of the present study was to investigate the correlation among PPAR-γ, CASK and insulin secretion. We found that rosiglitazone (RSG) had a positive effect on the expression of CASK and PPAR-γ in INS-1 cells as shown by real-time polymerase chain reaction (PCR) and western blot analysis, but did not change the cellular location of CASK as shown by immunofluorescence assay. Knockdown of PPAR-γ significantly attenuated the mRNA and protein expression levels of CASK. ChIP-qPCR and luciferase assays showed that PPAR-γ bound with the Cask promoter, and promoter activity of Cask was elevated by RSG. RSG significantly enhanced the insulin secretion with potassium stimulation, but did not alter the insulin content as shown by potassium-stimulated insulin secretion assay. In addition, with RSG pretreatment, knockdown of Cask did not significantly affect the PPAR-γ activation-mediated insulin secretion. Moreover, electron microscopy demonstrated that with RSG pretreatment, silence of Cask did not change the number of vesicles anchored on the cell membranes compared with those in siCask-treated cells. Overall, the present study identifies that CASK is one of the PPAR-γ downstream targets and PPAR-γ exerts a positive effect on the expression of CASK in INS-1 cells. PPAR-γ activation increases insulin secretion independent of the upregulation of CASK.
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Affiliation(s)
- Kai Zhang
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Medical School, Southeast University, Nanjing, China
| | - Qingzhao Yuan
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Medical School, Southeast University, Nanjing, China
| | - Jinyang Xie
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Medical School, Southeast University, Nanjing, China
| | - Li Yuan
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, China
| | - Yao Wang
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Medical School, Southeast University, Nanjing, China
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Luan P, Jian W, Xu X, Kou W, Yu Q, Hu H, Li D, Wang W, Feinberg MW, Zhuang J, Xu Y, Peng W. NLRC5 inhibits neointima formation following vascular injury and directly interacts with PPARγ. Nat Commun 2019; 10:2882. [PMID: 31253783 PMCID: PMC6599027 DOI: 10.1038/s41467-019-10784-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 05/29/2019] [Indexed: 12/16/2022] Open
Abstract
NLR Family CARD Domain Containing 5 (NLRC5), an important immune regulator in innate immunity, is involved in regulating inflammation and antigen presentation. However, the role of NLRC5 in vascular remodeling remains unknown. Here we report the role of NLRC5 on vascular remodeling and provide a better understanding of its underlying mechanism. Nlrc5 knockout (Nlrc5−/−) mice exhibit more severe intimal hyperplasia compared with wild-type mice after carotid ligation. Ex vivo data shows that NLRC5 deficiency leads to increased proliferation and migration of human aortic smooth muscle cells (HASMCs). NLRC5 binds to PPARγ and inhibits HASMC dedifferentiation. NACHT domain of NLRC5 is essential for the interaction with PPARγ and stimulation of PPARγ activity. Pioglitazone significantly rescues excessive intimal hyperplasia in Nlrc5−/− mice and attenuates the increased proliferation and dedifferentiation in NLRC5-deficient HASMCs. Our study demonstrates that NLRC5 regulates vascular remodeling by directly inhibiting SMC dysfunction via its interaction with PPARγ. NLRC5 is known for its role in inflammation and antigen presentation. Here Luan et al. find that NLRC5 protects mice from intimal hyperplasia following vascular injury, and regulates the response of vascular smooth muscle cells to injury through direct interaction with PPARγ.
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Affiliation(s)
- Peipei Luan
- Department of Cardiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China.,Department of Endocrinology, Xinhua Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai, 200092, China
| | - Weixia Jian
- Department of Endocrinology, Xinhua Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai, 200092, China
| | - Xu Xu
- Department of Cardiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Wenxin Kou
- Department of Cardiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Qing Yu
- Department of Cardiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Handan Hu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Dali Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Wei Wang
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, 10032, USA
| | - Mark W Feinberg
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Jianhui Zhuang
- Department of Cardiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China.
| | - Yawei Xu
- Department of Cardiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China.
| | - Wenhui Peng
- Department of Cardiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China.
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Huang W, Bencic DC, Flick RL, Nacci DE, Clark BW, Burkhard L, Lahren T, Biales AD. Characterization of the Fundulus heteroclitus embryo transcriptional response and development of a gene expression-based fingerprint of exposure for the alternative flame retardant, TBPH (bis (2-ethylhexyl)-tetrabromophthalate). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 247:696-705. [PMID: 30721860 PMCID: PMC7495336 DOI: 10.1016/j.envpol.2019.01.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 12/18/2018] [Accepted: 01/03/2019] [Indexed: 05/07/2023]
Abstract
Although alternative Flame Retardant (FR) chemicals are expected to be safer than the legacy FRs they replace, their risks to human health and the environment are often poorly characterized. This study used a small volume, fish embryo system to reveal potential mechanisms of action and diagnostic exposure patterns for TBPH (bis (2-ethylhexyl)-tetrabromophthalate), a component of several widely-used commercial products. Two different concentration of TBPH were applied to sensitive early life stages of an ecologically important test species, Fundulus heteroclitus (Atlantic killifish), with a well-annotated genome. Exposed fish embryos were sampled for transcriptomics or chemical analysis of parent compound and primary metabolite or observed for development and survival through larval stage. Global transcript profiling using RNA-seq was conducted (n = 16 per treatment) to provide a non-targeted and statistically robust approach to characterize TBPH gene expression patterns. Transcriptomic analysis revealed a dose-response in the expression of genes associated with a surprisingly limited number of biological pathways, but included the aryl hydrocarbon receptor signal transduction pathway, which is known to respond to several toxicologically-important chemical classes. A transcriptional fingerprint using Random Forests was developed that was able to perfectly discriminate exposed vs. non-exposed individuals in test sets. These results suggest that TBPH has a relatively low potential for developmental toxicity (at least in fishes), despite concerns related to its structural similarities to endocrine disrupting chemicals and that the early life stage Fundulus system may provide a convenient test system for exposure characterization. More broadly, this study advances the usefulness of a biological testing and analysis system utilizing non-targeted transcriptomics profiling and early developmental endpoints that complements current screening methods to characterize chemicals of ecological and human health concern.
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Affiliation(s)
- Weichun Huang
- U.S. EPA Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268, USA
| | - David C Bencic
- U.S. EPA Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268, USA
| | - Robert L Flick
- U.S. EPA Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268, USA
| | - Diane E Nacci
- U.S. EPA National Health and Environmental Effects Research Laboratory, 27 Tarzwell Drive Narragansett, RI, 02882, USA
| | - Bryan W Clark
- U.S. EPA National Health and Environmental Effects Research Laboratory, 27 Tarzwell Drive Narragansett, RI, 02882, USA
| | - Lawrence Burkhard
- U.S. EPA National Health and Environmental Effects Research Laboratory, 6201 Congdon Boulevard, Duluth, MN, 55804, USA
| | - Tylor Lahren
- U.S. EPA National Health and Environmental Effects Research Laboratory, 6201 Congdon Boulevard, Duluth, MN, 55804, USA
| | - Adam D Biales
- U.S. EPA Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268, USA.
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Zhang S, Ireland D, Sipes NS, Behl M, Collins EMS. Screening for neurotoxic potential of 15 flame retardants using freshwater planarians. Neurotoxicol Teratol 2019; 73:54-66. [PMID: 30943442 DOI: 10.1016/j.ntt.2019.03.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/22/2019] [Accepted: 03/25/2019] [Indexed: 10/27/2022]
Abstract
Asexual freshwater planarians are an attractive invertebrate model for high-throughput neurotoxicity screening, because they possess multiple quantifiable behaviors to assess distinct neuronal functions. Planarians uniquely allow direct comparisons between developing and adult animals to distinguish developmentally selective effects from general neurotoxicity. In this study, we used our automated planarian screening platform to compare the neurotoxicity of 15 flame retardants (FRs), consisting of representative phased-out brominated (BFRs) and replacement organophosphorus FRs (OPFRs). OPFRs have emerged as a proposed safer alternative to BFRs; however, limited information is available on their health effects. We found 11 of the 15 FRs (3/6 BFRs, 7/8 OPFRs, and Firemaster 550) caused adverse effects in both adult and developing planarians with similar nominal lowest-effect-levels for BFRs and OPFRs. This suggests that replacement OPFRs are comparably neurotoxic to the phased-out compounds. BFRs were primarily systemically toxic, whereas OPFRs, except Tris(2-chloroethyl) phosphate, shared a behavioral phenotype in response to noxious heat at sublethal concentrations, indicating specific neurotoxic effects. We found this behavioral phenotype was correlated with cholinesterase inhibition, thus linking behavioral outcomes to molecular targets. By directly comparing effects on adult and developing planarians, we further found that one BFR (3,3',5,5'-Tetrabromobisphenol A) caused a developmental selective defect. Together, these results demonstrate that our planarian screening platform yields high content data from various behavioral and morphological endpoints, allowing us to distinguish selective neurotoxic effects and effects specific to the developing nervous system. Ten of these 11 bioactive FRs were previously found to be bioactive in other models, including cell culture and alternative animal models (nematodes and zebrafish). This level of concordance across different platforms emphasizes the urgent need for further evaluation of OPFRs in mammalian systems.
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Affiliation(s)
- Siqi Zhang
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Danielle Ireland
- Division of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA; Department of Biology, Swarthmore College Swarthmore, PA 19081, USA
| | - Nisha S Sipes
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA
| | - Mamta Behl
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA
| | - Eva-Maria S Collins
- Division of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA; Department of Physics, University of California San Diego, La Jolla, CA 92093, USA; Department of Biology, Swarthmore College Swarthmore, PA 19081, USA.
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30
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Wang D, Yan S, Yan J, Teng M, Meng Z, Li R, Zhou Z, Zhu W. Effects of triphenyl phosphate exposure during fetal development on obesity and metabolic dysfunctions in adult mice: Impaired lipid metabolism and intestinal dysbiosis. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 246:630-638. [PMID: 30605818 DOI: 10.1016/j.envpol.2018.12.053] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 12/14/2018] [Accepted: 12/17/2018] [Indexed: 06/09/2023]
Abstract
Previous in vitro studies have implied that triphenyl phosphate (TPHP) may act as an obesogen. However, its specific contributions to the progression of obesity and related metabolic diseases are still unclear in vivo in mice. In this study, we evaluated the effects of in utero and lactational exposure to three doses of TPHP (10, 100, and 1000 μg/kg BW) on obesity and metabolic dysfunctions in adult male mice fed a low-fat diet (LFD) or high-fat diet (HFD), by examining body weight, liver weight, histopathology, blood biochemistry, gene expression, and gut microbiota compositions and metabolic functions. Results showed that TPHP exposure led to increased body weight, liver weight, fat mass, hepatic steatosis, impaired glucose homeostasis, and insulin resistance, and mRNA levels of genes involved in lipid metabolism, especially lipogenesis and lipid accumulation, were significantly altered by TPHP treatment. Gas chromatography-mass spectrometry (GC-MS) analysis further supported the changes in fatty acid composition. Intestinal flora measurements by 16S rRNA gene sequencing and 1H NMR based fecal metabolomics indicated that TPHP treatment modulated gut microbiome composition and influenced host-gut co-metabolism, especially for bile acids and short chain fatty acids (SCFAs). These results suggest that fetal exposure to TPHP can promote the development of obesity and metabolic dysfunctions in adult mice.
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Affiliation(s)
- Dezhen Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, PR China
| | - Sen Yan
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, PR China
| | - Jin Yan
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, PR China
| | - Miaomiao Teng
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, PR China
| | - Zhiyuan Meng
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, PR China
| | - Ruisheng Li
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, PR China
| | - Zhiqiang Zhou
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, PR China
| | - Wentao Zhu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, PR China.
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Chokwe TB, Magubane MN, Abafe OA, Okonkwo JO, Sibiya IV. Levels, distributions, and ecological risk assessments of polybrominated diphenyl ethers and alternative flame retardants in river sediments from Vaal River, South Africa. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:7156-7163. [PMID: 30648238 DOI: 10.1007/s11356-018-04063-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 12/20/2018] [Indexed: 06/09/2023]
Abstract
Sediments are known to be the ultimate sink for most pollutants in the aquatic environment. In this study, the concentrations of both legacy polybrominated diphenyl ethers (PBDEs) and alternative halogenated flame retardants (AHFRs) were measured in sediments samples from the Vaal River catchment. The concentrations of Σ7BDE-congeners ranged from 20 to 78 ng g-1 dry weight (dw) with BDE-209, -99, and -153 as the dominant congeners. The concentrations observed ranged from 9.4-56, 4-32, and 1-10.6 ng g-1 for BDE-209, -99, and -153, respectively. The concentrations of AHFRs, mainly contributed by decabromodiphenyl ethane (DBDPE) at approximately 95% of total AHFRs, ranged from 64 to 359 ng g-1 dw while the concentration of polybrominated biphenyls (PBBs), mainly PBB-209, ranged from 3.3-7.1 ng g-1 dw. The ratios of AHFRs to PBDEs observed in this study were 0.76, 1.17, and 7.3 for 2-ethyl-1-hexyl-2,3,4,5-tetrabromobenzoate and bis-(2-ethylhexyl)-tetrabromophthalate (EH-TBB & BEH-TEBP)/penta-BDE; 1,2-bis-(2,4,6-tribromophenoxy) ethane (BTBPE)/octa-BDE; and DBDPE/BDE209, respectively. These results indicate dominance of some AHFRs compared to PBDEs. Our results indicates that BDE-99 poses high risk (RQ > 1) while BDE-209 posed medium risk (0.1 < RQ < 1). Though the concentration of DBDPE was several orders of magnitude higher than BDE209, its ecological risk was found to be negligible (RQ < 0.01). Thus, more attention is required to regulate the input (especially the e-waste recycling sites) of brominated flame retardants into the environment.
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Affiliation(s)
- Tlou B Chokwe
- Rand Water Scientific Services, 2 Barrage Road, Vereeniging, 1930, Republic of South Africa.
| | - Makhosazane N Magubane
- Rand Water Scientific Services, 2 Barrage Road, Vereeniging, 1930, Republic of South Africa
| | - Ovokeroye A Abafe
- Agricultural Research Council -OVR, 100 Old Soutpan Road, Onderstepoort, Pretoria, 0110, Republic of South Africa
| | - Jonathan O Okonkwo
- Department of Water, Environmental and Earth Sciences, Tshwane University of Technology, 175 Mandela Road, Pretoria, 0001, Republic of South Africa
| | - Innocentia V Sibiya
- Department of Water, Environmental and Earth Sciences, Tshwane University of Technology, 175 Mandela Road, Pretoria, 0001, Republic of South Africa
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32
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Hartman JK, Beames T, Parks B, Doheny D, Song G, Efremenko A, Yoon M, Foley B, Deisenroth C, McMullen PD, Clewell RA. An in vitro approach for prioritization and evaluation of chemical effects on glucocorticoid receptor mediated adipogenesis. Toxicol Appl Pharmacol 2018; 355:112-126. [DOI: 10.1016/j.taap.2018.05.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 05/14/2018] [Accepted: 05/15/2018] [Indexed: 11/25/2022]
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Nacci D, Clark B, La Guardia MJ, Miller K, Champlin D, Kirby I, Bertrand A, Jayaraman S. Bioaccumulation and effects of dietary exposure to the alternative flame retardant, bis(2-ethylhexyl) tetrabromophthalate (TBPH), in the Atlantic killifish, Fundulus heteroclitus. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2018; 37:2350-2360. [PMID: 29846010 PMCID: PMC6123825 DOI: 10.1002/etc.4180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 02/05/2018] [Accepted: 05/29/2018] [Indexed: 05/23/2023]
Abstract
Bis(2-ethylhexyl) tetrabromophthalate (TBPH), a high production volume flame retardant chemical used as a replacement for banned flame retardants, has been detected in media and human and wildlife tissues globally. We describe bioaccumulation and biological effects from dietary exposure of TBPH to an estuarine fish, Atlantic killifish, Fundulus heteroclitus. Briefly, adult fish were fed carrier control or chemically amended diets for 28 d, followed by 14 d of control diet feeding. Diets were amended with TBPH (TBPH_LO diet, 139 μg/g dry wt, or TBPH_HI diet, 4360 μg/g dry wt) or a polychlorinated biphenyl congener (PCB153 diet, 13 μg/g dry wt), which was included as a positive control for bioaccumulation. Although bioaccumulation of either chemical correlated with fish size, only a small proportion of the TBPH offered (<0.5% total TBPH) had bioaccumulated into TBPH-treated fish by 28 d. In contrast, 24.5% of the PCB153 offered was accounted for in 28-d PCB-treated fish. Although 28-d bioaccumulated concentrations of TBPH differed by sex and treatment, sexes did not differ in their rates of TBPH bioaccumulation, and the time to achieve 50% of 28 d concentration (T1/2 ) was estimated to be 13 d. Depuration rates of TBPH did not differ by sex or treatment, and the time after exposure to achieve T1/2 was estimated to be 22 d. Independent of treatment, male fish grew faster than female fish, but for both sexes reproductive condition (gonadal somatic index) declined unexpectedly over the experimental period. Across treatments, only the TBPH_LO treatment affected growth, reducing male but increasing female growth rates by small amounts relative to respective controls. In summary, our study used very high concentrations of dietary TBPH to contaminate fish tissues above the highest levels reported to date in wild biota, yet we observed few adverse biological effects. Environ Toxicol Chem 2018;37:2350-2360. © 2018 SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
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Affiliation(s)
- Diane Nacci
- Atlantic Ecology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Narragansett, Rhode Island, USA
| | - Bryan Clark
- Atlantic Ecology Division, Oak Ridge Institute for Science and Education, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Narragansett, Rhode Island, USA
| | - Mark J La Guardia
- Aquatic Health Sciences, Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, Virginia, USA
| | - Ken Miller
- CSC Government Solutions, A CSRA Company, Alexandria, Virginia, USA
| | - Denise Champlin
- Atlantic Ecology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Narragansett, Rhode Island, USA
| | - Ian Kirby
- Atlantic Ecology Division, Student Services Contractor, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Narragansett, Rhode Island, USA
| | - Ashley Bertrand
- Atlantic Ecology Division, Student Services Contractor, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Narragansett, Rhode Island, USA
| | - Saro Jayaraman
- Atlantic Ecology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Narragansett, Rhode Island, USA
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Wong F, de Wit CA, Newton SR. Concentrations and variability of organophosphate esters, halogenated flame retardants, and polybrominated diphenyl ethers in indoor and outdoor air in Stockholm, Sweden. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 240:514-522. [PMID: 29758525 DOI: 10.1016/j.envpol.2018.04.086] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/19/2018] [Accepted: 04/19/2018] [Indexed: 05/16/2023]
Abstract
We investigated the concentrations and temporal variability of organophospate esters (OPEs), halogenated flame retardants (HFRs) and polybrominated diphenyl ethers (PBDEs) in indoor and outdoor urban air in Stockholm, Sweden over one year (2014-2015) period. The median concentrations of the three target chemical groups (OPEs, HFRs, PBDEs) were 1-2 orders of magnitude higher in indoor air than outdoor urban air. OPEs were the most abundant target FRs with median concentrations in indoor (Σ10OPE = 340 000 pg/m3) and outdoor urban (Σ10OPEs = 3100 pg/m3) air, being 3 orders of magnitude greater than for HFRs in indoor (Σ15HFRs = 120 pg/m3) and outdoor urban (Σ15HFRs = 1.6 pg/m3) air. In indoor air, PBDE concentrations (Σ17PBDEs = 33 pg/m3) were lower than for the HFRs, but in outdoor urban air, concentrations (Σ17PBDEs = 1.1 pg/m3) were similar to HFRs. The most abundant OPEs in both the indoor and outdoor urban air were tris(2-butoxyethyl)phosphate (TBOEP), tris(chloroisopropyl)phosphate (TCIPP), tris(2-chloroethyl)phosphate (TCEP), tri-n-butyl-phosphate (TnBP), triphenyl phosphate (TPhP) and tris(1,3-dichloroisopropyl)phosphate (TDCIPP). TCIPP in indoor air was found in the highest concentrations and showed the greatest temporal variability, which ranged from 85 000 to 1 900 000 pg/m3 during the one-year sampling period. We speculate that activities in the building, e.g. floor cleaning, polishing, construction, introduction of new electronics and changes in ventilation rate could explain its variation. Some OPEs (TnBP, TCEP, TCIPP, TDCIPP and TPhP), HFRs/PBDEs (pentabromotoluene, 2, 3-dibromopropyl 2, 4, 6-tribromophenyl ether, hexabromobenzene, BDE-28, -47, and -99) in outdoor urban air showed seasonality, with increased concentrations during the warm period (p < 0.05, Pearson's r ranged from -0.45 to -0.91). The observed seasonality for OPEs was probably due to changes in primary emission, and those for the HFRs and PBDEs was likely due to re-volatilization from contaminated surfaces.
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Affiliation(s)
- Fiona Wong
- Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University, SE-106 91 Stockholm, Sweden.
| | - Cynthia A de Wit
- Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University, SE-106 91 Stockholm, Sweden
| | - Seth R Newton
- Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University, SE-106 91 Stockholm, Sweden
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Krumm EA, Patel VJ, Tillery TS, Yasrebi A, Shen J, Guo GL, Marco SM, Buckley BT, Roepke TA. Organophosphate Flame-Retardants Alter Adult Mouse Homeostasis and Gene Expression in a Sex-Dependent Manner Potentially Through Interactions With ERα. Toxicol Sci 2018; 162:212-224. [PMID: 29112739 PMCID: PMC6735580 DOI: 10.1093/toxsci/kfx238] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Flame retardants (FRs) such as polybrominated diphenyl ethers and organophosphate FR (OPFR) persist in the environment and interact with multiple nuclear receptors involved in homeostasis, including estrogen receptors (ERs). However, little is known about the effects of FR, especially OPFR, on mammalian neuroendocrine functions. Therefore, we investigated if exposure to FR alters hypothalamic gene expression and whole-animal physiology in adult wild-type (WT) and ERα KO mice. Intact WT and KO males and ovariectomized WT and KO females were orally dosed daily with vehicle (oil), 17α-ethynylestradiol (2.5 μg/kg), 2,2', 4,4-tetrabromodiphenyl ether (BDE-47, 1 or 10 mg/kg), or an OPFR mixture {1 or 10 mg/kg of tris(1, 3-dichloro-2-propyl)phosphate, triphenyl phosphate, and tricresyl phosphate each} for 28 days. Body weight, food intake, body composition, glucose and insulin tolerance, plasma hormone levels, and hypothalamic and liver gene expression were measured. Expression of neuropeptides, receptors, and cation channels was differentially altered between WT males and females. OPFR suppressed body weight and energy intake in males. FR increased fasting glucose levels in males, and BDE-47 augmented glucose clearance in females. Liver gene expression indicated FXR activation by BDE-47 and PXR and CAR activation by OPFR. In males, OPFR increased ghrelin but decreased leptin and insulin independent of body weight. The loss of ERα reduced the effects of both FR on hypothalamic and liver gene expression and plasma hormone levels. The physiological implications are that males are more sensitive than ovariectomized females to OPFR exposure and that these effects are mediated, in part, by ERα.
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Affiliation(s)
- Elizabeth A Krumm
- Department of Animal Sciences, School of Environmental & Biological Sciences
- Graduate Program in Endocrinology and Animal Biosciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey
| | - Vipa J Patel
- Department of Animal Sciences, School of Environmental & Biological Sciences
| | - Taylor S Tillery
- Department of Animal Sciences, School of Environmental & Biological Sciences
| | - Ali Yasrebi
- Department of Animal Sciences, School of Environmental & Biological Sciences
- Graduate Program in Endocrinology and Animal Biosciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey
| | - Jianliang Shen
- Department of Pharmacology and Toxicology, School of Pharmacy, Rutgers University, Piscataway, New Jersey 08854
| | - Grace L Guo
- Department of Pharmacology and Toxicology, School of Pharmacy, Rutgers University, Piscataway, New Jersey 08854
| | | | - Brian T Buckley
- Environmental and Occupational Health Science Institute, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Troy A Roepke
- Department of Animal Sciences, School of Environmental & Biological Sciences
- Graduate Program in Endocrinology and Animal Biosciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey
- Joint Graduate Program in Toxicology
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36
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Phillips AL, Hammel SC, Konstantinov A, Stapleton HM. Characterization of Individual Isopropylated and tert-Butylated Triarylphosphate (ITP and TBPP) Isomers in Several Commercial Flame Retardant Mixtures and House Dust Standard Reference Material SRM 2585. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:13443-13449. [PMID: 29076339 PMCID: PMC5966724 DOI: 10.1021/acs.est.7b04179] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Since the phase-out of pentaBDE in the early 2000s, replacement flame-retardant mixtures including Firemaster 550 (FM 550), Firemaster 600 (FM 600), and organophosphate aryl ester technical mixtures have been increasingly used to treat polyurethane foam in residential upholstered furniture. These mixtures contain isomers of isopropylated and tert-butylated triarylphosphate esters (ITPs and TBPPs), which have similar or greater neuro- and developmental toxicity compared to BDE 47 in high-throughput assays. Additionally, human exposure to ITPs and TBPPs has been demonstrated to be widespread in several recent studies; however, the relative composition of these mixtures has remained largely uncharacterized. Using available authentic standards, the present study quantified the contribution of individual ITP and TBPP isomers in four commercial flame retardant mixtures: FM 550, FM 600, an ITP mixture, and a TBPP mixture. Findings suggest similarities between FM 550 and the ITP mixture, with 2-isopropylphenyl diphenyl phosphate (2IPPDPP), 2,4-diisopropylphenyl diphenyl phosphate (24DIPPDPP), and bis(2-isopropylphenyl) phenyl phosphate (B2IPPPP) being the most prevalent ITP isomers in both mixtures. FM 600 differed from FM 550 in that it contained TBPP isomers instead of ITP isomers. These analytes were also detected and quantified in a house dust standard reference material, SRM 2585, demonstrating their environmental relevance.
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Affiliation(s)
- Allison L. Phillips
- Nicholas School of the Environment, Duke University, Durham, North Carolina, 27708 United States
| | - Stephanie C. Hammel
- Nicholas School of the Environment, Duke University, Durham, North Carolina, 27708 United States
| | | | - Heather M. Stapleton
- Nicholas School of the Environment, Duke University, Durham, North Carolina, 27708 United States
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37
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Tung EWY, Peshdary V, Gagné R, Rowan-Carroll A, Yauk CL, Boudreau A, Atlas E. Adipogenic Effects and Gene Expression Profiling of Firemaster® 550 Components in Human Primary Preadipocytes. ENVIRONMENTAL HEALTH PERSPECTIVES 2017; 125:097013. [PMID: 28934090 PMCID: PMC5915190 DOI: 10.1289/ehp1318] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 05/18/2017] [Accepted: 05/23/2017] [Indexed: 05/27/2023]
Abstract
BACKGROUND Exposure to flame retardants has been associated with negative health outcomes including metabolic effects. As polybrominated diphenyl ether flame retardants were pulled from commerce, human exposure to new flame retardants such as Firemaster® 550 (FM550) has increased. Although previous studies in murine systems have shown that FM550 and its main components increase adipogenesis, the effects of FM550 in human models have not been elucidated. OBJECTIVES The objectives of this study were to determine if FM550 and its components are active in human preadipocytes, and to further investigate their mode of action. METHODS Human primary preadipocytes were differentiated in the presence of FM550 and its components. Differentiation was assessed by lipid accumulation and expression of peroxisome proliferator-activated receptor γ (PPARG), fatty acid binding protein (FABP) 4 and lipoprotein lipase (LPL). mRNA was collected for Poly (A) RNA sequencing and was used to identify differentially expressed genes (DEGs). Functional analysis of DEGs was undertaken in Ingenuity Pathway Analysis. RESULTS FM550 triphenyl phosphate (TPP) and isopropylated triphenyl phosphates (IPTP), increased adipogenesis in human primary preadipocytes as assessed by lipid accumulation and mRNA expression of regulators of adipogenesis such as PPARγ, CCAAT enhancer binding protein (C/EBP) α and sterol regulatory element binding protein (SREBP) 1 as well as the adipogenic markers FABP4 LPL and perilipin. Poly (A) RNA sequencing analysis revealed potential modes of action including liver X receptor/retinoid X receptor (LXR/RXR) activation, thyroid receptor (TR)/RXR, protein kinase A, and nuclear receptor subfamily 1 group H members activation. CONCLUSIONS We found that FM550, and two of its components, induced adipogenesis in human primary preadipocytes. Further, using global gene expression analysis we showed that both TPP and IPTP likely exert their effects through PPARG to induce adipogenesis. In addition, IPTP perturbed signaling pathways that were not affected by TPP. https://doi.org/10.1289/EHP1318.
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Affiliation(s)
- Emily W Y Tung
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
| | - Vian Peshdary
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
| | - Remi Gagné
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
| | - Andrea Rowan-Carroll
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
| | - Carole L Yauk
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
| | - Adéle Boudreau
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
| | - Ella Atlas
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
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Baldwin KR, Phillips AL, Horman B, Arambula SE, Rebuli ME, Stapleton HM, Patisaul HB. Sex Specific Placental Accumulation and Behavioral Effects of Developmental Firemaster 550 Exposure in Wistar Rats. Sci Rep 2017; 7:7118. [PMID: 28769031 PMCID: PMC5540931 DOI: 10.1038/s41598-017-07216-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 06/23/2017] [Indexed: 12/20/2022] Open
Abstract
Firemaster® 550 (FM 550) is a commercial flame retardant mixture of brominated and organophosphate compounds applied to polyurethane foam used in furniture and baby products. Due to widespread human exposure, and structural similarities with known endocrine disruptors, concerns have been raised regarding possible toxicity. We previously reported evidence of sex specific behavioral effects in rats resulting from developmental exposure. The present study expands upon this prior finding by testing for a greater range of behavioral effects, and measuring the accumulation of FM 550 compounds in placental tissue. Wistar rat dams were orally exposed to FM 550 during gestation (0, 300 or 1000 µg/day; GD 9 – 18) for placental measurements or perinatally (0, 100, 300 or 1000 µg/day; GD 9 – PND 21) to assess activity and anxiety-like behaviors. Placental accumulation was dose dependent, and in some cases sex specific, with the brominated components reaching the highest levels. Behavioral changes were predominantly associated with a loss or reversal of sex differences in activity and anxiety-like behaviors. These findings demonstrate that environmental chemicals may sex-dependently accumulate in the placenta. That sex-biased exposure might translate to sex-specific adverse outcomes such as behavioral deficits is a possibility that merits further investigation.
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Affiliation(s)
- Kylie R Baldwin
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, 27695, USA
| | - Allison L Phillips
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - Brian Horman
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, 27695, USA
| | - Sheryl E Arambula
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, 27695, USA
| | - Meghan E Rebuli
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, 27695, USA
| | | | - Heather B Patisaul
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, 27695, USA. .,Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, 27695, USA.
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