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Schkoda S, Horman B, Witchey S, St Armour G, Nelson M, Gaeta E, Scott M, Patisaul HB. Sex-specific effects on elements of the social brain neural network in Wistar rats from perinatal exposure to FireMaster 550 or its components. Neurotoxicology 2024; 105:111-120. [PMID: 39241866 DOI: 10.1016/j.neuro.2024.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2024] [Accepted: 09/03/2024] [Indexed: 09/09/2024]
Abstract
Developmental exposure to chemical flame retardants (FRs) has been linked to a variety of neurodevelopmental disorders and abnormal socioemotional behaviors in human and laboratory animal studies. We have previously shown in Wistar rats that gestational and lactational exposure to the FR mixture Firemaster 550 (FM 550) or its brominated or organophosphate ester (OPFR) components (at 2000 µg, 1000 µg, and 1000 µg oral to the dam respectively (absolute and not by bodyweight)) results in increased anxiety-like behaviors in females and decreased sociality in both sexes. Using their siblings, this study characterized sex and chemical specific targets of disruption in brain regions underlying each behavioral phenotype. Offspring were exposed across gestation and lactation then prepared for either immunohistochemistry or autoradiography at postnatal day 90 to quantify expression of serotonin, estrogen receptor α (ERα), and oxytocin receptor (OTR) in multiple brain regions. No effect of exposure was found in males for any biological target. In females, serotonin innervation was increased in the medial amygdala of FM 550 exposed animals while ERα expression in the bed nucleus of the stria terminalis (BNST) was reduced by FM 550 and OPFR. Evidence of disrupted OTR was observed in males, particularly the BNST but considered an exploratory finding given the small sample size. These results begin to shed light on the mechanisms by which developmental FR exposure alters socioemotional behaviors of relevance to neurodevelopmental disorders.
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Affiliation(s)
- Stacy Schkoda
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States
| | - Brian Horman
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States
| | - Shannah Witchey
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States
| | - Genevieve St Armour
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC 27695, United States
| | - Mason Nelson
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States
| | - Emily Gaeta
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States
| | - Madeline Scott
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States
| | - Heather B Patisaul
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC 27695, United States.
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Wang X, Rowan-Carroll A, Meier MJ, Yauk CL, Wade MG, Robaire B, Hales BF. House dust-derived mixtures of organophosphate esters alter the phenotype, function, transcriptome, and lipidome of KGN human ovarian granulosa cells. Toxicol Sci 2024; 200:95-113. [PMID: 38603619 PMCID: PMC11199920 DOI: 10.1093/toxsci/kfae052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024] Open
Abstract
Organophosphate esters (OPEs), used as flame retardants and plasticizers, are present ubiquitously in the environment. Previous studies suggest that exposure to OPEs is detrimental to female fertility in humans. However, no experimental information is available on the effects of OPE mixtures on ovarian granulosa cells, which play essential roles in female reproduction. We used high-content imaging to investigate the effects of environmentally relevant OPE mixtures on KGN human granulosa cell phenotypes. Perturbations to steroidogenesis were assessed using ELISA and qRT-PCR. A high-throughput transcriptomic approach, TempO-Seq, was used to identify transcriptional changes in a targeted panel of genes. Effects on lipid homeostasis were explored using a cholesterol assay and global lipidomic profiling. OPE mixtures altered multiple phenotypic features of KGN cells, with triaryl OPEs in the mixture showing higher potencies than other mixture components. The mixtures increased basal production of steroid hormones; this was mediated by significant changes in the expression of critical transcripts involved in steroidogenesis. Further, the total-OPE mixture disrupted cholesterol homeostasis and the composition of intracellular lipid droplets. Exposure to complex mixtures of OPEs, similar to those found in house dust, may adversely affect female reproductive health by altering a multitude of phenotypic and functional endpoints in granulosa cells. This study provides novel insights into the mechanisms of actions underlying the toxicity induced by OPEs and highlights the need to examine the effects of human relevant chemical mixtures.
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Affiliation(s)
- Xiaotong Wang
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec, H3G 1Y6, Canada
| | - Andrea Rowan-Carroll
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, K1A 0K9, Canada
| | - Matthew J Meier
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, K1A 0K9, Canada
| | - Carole L Yauk
- Department of Biology, University of Ottawa, Ottawa, Ontario, K1N 9A7, Canada
| | - Michael G Wade
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, K1A 0K9, Canada
| | - Bernard Robaire
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec, H3G 1Y6, Canada
- Department of Obstetrics and Gynecology, McGill University, Montréal, Quebec, H3G 1Y6, Canada
| | - Barbara F Hales
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec, H3G 1Y6, Canada
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Zhou Y, Lei L, Zhu B, Li R, Zuo Y, Guo Y, Han J, Yang L, Zhou B. Aggravated visual toxicity in zebrafish larvae upon co-exposure to titanium dioxide nanoparticles and bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171133. [PMID: 38395162 DOI: 10.1016/j.scitotenv.2024.171133] [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: 12/07/2023] [Revised: 02/18/2024] [Accepted: 02/19/2024] [Indexed: 02/25/2024]
Abstract
The bioavailability and toxicity of organic pollutants in aquatic organisms can be largely affected by the co-existed nanoparticles. However, the impacts of such combined exposure on the visual system remain largely unknown. Here, we systematically investigated the visual toxicity in zebrafish larvae after single or joint exposure to titanium dioxide nanoparticles (n-TiO2) and bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH) at environmentally relevant levels. Molecular dynamics simulations revealed the enhanced transmembrane capability of the complex than the individual, which accounted for the increased bioavailability of both TBPH and n-TiO2 when combined exposure to zebrafish. Transcriptome analysis showed that co-exposure to n-TiO2 and TBPH interfered with molecular pathways related to eye lens structure and sensory perception of zebrafish. Particularly, n-TiO2 or TBPH significantly suppressed the expression of βB1-crystallin and rhodopsin in zebrafish retina and lens, which was further enhanced after co-exposure. Moreover, we detected disorganized retinal histology, stunted lens development and significant visual behavioral changes of zebrafish under co-exposure condition. The overall results suggest that combined exposure to water borne n-TiO2 and TBPH increased their bioavailability, resulted in severer damage to optic nerve development and ultimately abnormal visual behavior patterns, highlighting the higher potential health risks of co-exposure to aquatic vertebrates.
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Affiliation(s)
- Yuxi Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
| | - Lei Lei
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
| | - Biran Zhu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
| | - Ruiwen Li
- Ecological Environment Monitoring and Scientific Research Center, Changjiang River Basin Ecological Environment Administration, Ministry of Ecology and Environment, Wuhan 430014, PR China
| | - Yanxia Zuo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
| | - Yongyong Guo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
| | - Jian Han
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
| | - Lihua Yang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China.
| | - Bingsheng Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
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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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Marinello WP, Gillera SEA, Huang L, Rollman J, Reif DM, Patisaul HB. Uncovering the common factors of chemical exposure and behavior: Evaluating behavioral effects across a testing battery using factor analysis. Neurotoxicology 2023; 99:264-273. [PMID: 37914043 PMCID: PMC11154886 DOI: 10.1016/j.neuro.2023.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 10/09/2023] [Accepted: 10/26/2023] [Indexed: 11/03/2023]
Abstract
Although specific environmental chemical exposures, including flame retardants, are known risk factors for neurodevelopmental disorders (NDDs), direct experimental evidence linking specific chemicals to NDDs is limited. Studies focusing on the mechanisms by which the social processing systems are vulnerable to chemical exposure are underrepresented in the literature, even though social impairments are defining characteristics of many NDDs. We have repeatedly demonstrated that exposure to Firemaster 550 (FM 550), a prevalent flame retardant mixture used in foam-based furniture and infant products, can adversely impact a variety of behavioral endpoints. Our recent work in prairie voles (Microtus ochrogaster), a prosocial animal model, demonstrated that perinatal exposure to FM 550 sex specifically impacts socioemotional behavior. Here, we utilized a factor analysis approach on a battery of behavioral data from our prior study to extract underlying factors that potentially explain patterns within the FM 550 behavior data. This approach identified which aspects of the behavioral battery are most robust and informative, an outcome critical for future study designs. Pearson's correlation identified behavioral endpoints associated with distance and stranger interactions that were highly correlated across 5 behavioral tests. Using these behavioral endpoints, exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) extracted 2 factors that could explain the data: Activity (distance traveled endpoints) and Sociability (time spent with a novel conspecific). Exposure to FM 550 significantly decreased Activity and decreased Sociability. This factor analysis approach to behavioral data offers the advantages of modeling numerous measured variables and simplifying the data set by presenting the data in terms of common, overarching factors in terms of behavioral function.
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Affiliation(s)
- William P Marinello
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, USA
| | - Sagi Enicole A Gillera
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, USA; ICF International Inc, Durham, NC 27713, USA
| | - Lynn Huang
- Department of Statistics, NC State University, Raleigh, NC 27695, USA
| | - John Rollman
- Department of Statistics, NC State University, Raleigh, NC 27695, USA
| | - David M Reif
- Bioinformatics Research Center, 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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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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Berger ML, Shaw SD, Rolsky C, Harris JH, Guo Y, Kannan K. Occurrence and tissue-specific partitioning of alternative brominated flame retardants in northwest Atlantic harbor seal pups (Phoca vitulina vitulina). CHEMOSPHERE 2023; 318:137968. [PMID: 36708778 DOI: 10.1016/j.chemosphere.2023.137968] [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: 10/24/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Brominated flame retardants such as polybrominated diphenyl ethers (PBDEs) have been used for decades until evidence of negative health effects led to bans in many countries. PBDEs have since been replaced by alternative legacy compounds or newly developed chemicals. In this study, eight alternative brominated flame retardants were analyzed in blubber and liver of harbor seal pups (≤6 months) from the Northwest Atlantic collected during 2001-2010 to elucidate concentrations, patterns, contamination trends, potential maternal transfer, and tissue partitioning. All compounds were detected in liver and blubber tissues with hexabromocyclododecane (HBCD) isomers and 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB) predominating. Overall, α-HBCD was the dominant HBCD isomer in both tissues although the concentrations of γ-HBCD exceeded those of α-HBCD in seven pups, indicating their mothers may have had alternative dietary patterns or recent exposure to the commercial mixture. Although it was detected in less than half of the samples, to our knowledge, this is the first study to report tetrabromobisphenol A (TBBPA) concentrations in multiple tissues of a top marine predator. For the brominated components of Firemaster® flame retardants, TBB concentrations exceeded bis-(2-ethylhexyl)-tetrabromophthalate (TBPH). This pattern may result from recent exposure to commercial mixtures in which TBB exceeds TBPH 4:1 or from differences in perinatal or lactational transfer efficiency of the two compounds. Between the two tissues, lipid-normalized β-HBCD, γ-HBCD, TBB and decabromodiphenyl ethane (DBDPE) concentrations were significantly higher in liver than blubber. This indicates that the bioaccumulation of these chemicals is not simply related to lipid dynamics but may be linked to blood proteins. This study demonstrates that harbor seal pups from this region are contaminated with alternative flame retardants passed to them via placental or lactational transfer. Given the evidence for negative health effects of these chemicals, this contamination adds additional pressure on the first year survival of these young, developing animals.
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Affiliation(s)
- Michelle L Berger
- Shaw Institute, Blue Hill Research Center, 55 Main Street, Blue Hill, ME, 04614, USA.
| | - Susan D Shaw
- Shaw Institute, Blue Hill Research Center, 55 Main Street, Blue Hill, ME, 04614, USA
| | - Charles Rolsky
- Shaw Institute, Blue Hill Research Center, 55 Main Street, Blue Hill, ME, 04614, USA
| | - Jennifer H Harris
- Shaw Institute, Blue Hill Research Center, 55 Main Street, Blue Hill, ME, 04614, USA
| | - Ying Guo
- School of Environment, Jinan University, Guangzhou, 510632, China
| | - Kurunthachalam Kannan
- Department of Pediatrics and Department of Environmental Medicine, New York University School of Medicine, 550 First Avenue, 698 MSB 6th Floor, New York, NY, 10016, USA
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Kou J, Li X, Zhang M, Wang L, Hu L, Liu X, Mei S, Xu G. Accumulative levels, temporal and spatial distribution of common chemical pollutants in the blood of Chinese adults. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 311:119980. [PMID: 35985432 DOI: 10.1016/j.envpol.2022.119980] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 06/15/2023]
Abstract
China has been in a rapid development period in recent decades, the mass production and use of chemical industrial products and pesticides have resulted in a large amount of pollutants in the environment. These pollutants enter the human body through environmental exposure and dietary intake, causing adverse health effects. Although many of them have been banned and restricted in the production and use in China, these pollutants still remain in the human body due to their high persistence and strong bioaccumulation. In this review, we aim to reveal the accumulation levels and profiles, as well as the temporal and spatial distribution of common chemical pollutants including chlorinated paraffins (CPs), polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers, organophosphorus flame retardants (OPFRs), new halogenated flame retardants (NHFRs), polychlorinated biphenyls, phthalic acid esters, perfluorinated compounds, bisphenols, organophosphorus pesticides and pyrethroid insecticides in the blood (including whole blood, serum and plasma) of Chinese adults by extracting 93 related studies published from 1990 to 2021. Results have shown that CPs, OCPs and PAHs were the main pollutants in China, the levels of short-chain chlorinated paraffin, p,p'-DDE and phenanthrene in blood even reached 11,060.58, 740.41 and 498.28 ng/g lipid respectively. Under the strict control of pollutants in China, the levels of most pollutants have been on a downward trend except for perfluoro octanoate and perfluoro nonanoate. Besides, OPFRs, NHFRs and PAHs may have a potential upward trend, requiring further research and observation. As for spatial distribution, East China (Bohai Bay and Yangtze River Delta) and South China (Pearl River Delta) were the major polluted regions due to their fast development of industry and agriculture.
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Affiliation(s)
- Jing Kou
- State Key Laboratory of Environment Health (Incubation), Key Laboratory of Environment and Health, Ministry of Education, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, #13 Hangkong Road, Wuhan, Hubei, 430030, China
| | - Xiang Li
- State Key Laboratory of Environment Health (Incubation), Key Laboratory of Environment and Health, Ministry of Education, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, #13 Hangkong Road, Wuhan, Hubei, 430030, China
| | - Mingye Zhang
- State Key Laboratory of Environment Health (Incubation), Key Laboratory of Environment and Health, Ministry of Education, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, #13 Hangkong Road, Wuhan, Hubei, 430030, China
| | - Limei Wang
- State Key Laboratory of Environment Health (Incubation), Key Laboratory of Environment and Health, Ministry of Education, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, #13 Hangkong Road, Wuhan, Hubei, 430030, China
| | - Liqin Hu
- State Key Laboratory of Environment Health (Incubation), Key Laboratory of Environment and Health, Ministry of Education, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, #13 Hangkong Road, Wuhan, Hubei, 430030, China
| | - Xinyu Liu
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China; Liaoning Province Key Laboratory of Metabolomics, Dalian, China
| | - Surong Mei
- State Key Laboratory of Environment Health (Incubation), Key Laboratory of Environment and Health, Ministry of Education, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, #13 Hangkong Road, Wuhan, Hubei, 430030, China.
| | - Guowang Xu
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China; Liaoning Province Key Laboratory of Metabolomics, Dalian, China
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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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10
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Marinello WP, Gillera SEA, Fanning MJ, Malinsky LB, Rhodes CL, Horman BM, Patisaul HB. Effects of developmental exposure to FireMaster® 550 (FM 550) on microglia density, reactivity and morphology in a prosocial animal model. Neurotoxicology 2022; 91:140-154. [PMID: 35526706 DOI: 10.1016/j.neuro.2022.04.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 11/20/2022]
Abstract
Microglia are known to shape brain sex differences critical for social and reproductive behaviors. Chemical exposures can disrupt brain sexual differentiation but there is limited data regarding how they may impact microglia distribution and function. We focused on the prevalent flame retardant mixture Firemaster 550 (FM 550) which is used in foam-based furniture and infant products including strollers and nursing pillows because it disrupts sexually dimorphic behaviors. We hypothesized early life FM 550 exposure would disrupt microglial distribution and reactivity in brain regions known to be highly sexually dimorphic or associated with social disorders in humans. We used prairie voles (Microtus ochrogaster) because they display spontaneous prosocial behaviors not seen in rats or mice and are thus a powerful model for studying chemical exposure-related impacts on social behaviors and their underlying neural systems. We have previously demonstrated that perinatal FM 550 exposure sex-specifically impacts socioemotional behaviors in prairie voles. We first established that, unlike in rats, the postnatal colonization of the prairie vole brain is not sexually dimorphic. Vole dams were then exposed to FM 550 (0, 500, 1000, 2000 µg/day) via subcutaneous injections through gestation, and pups were directly exposed beginning the day after birth until weaning. Adult offspring's brains were assessed for number and type (ramified, intermediate, ameboid) of microglia in the medial prefrontal cortex (mPFC), cerebellum (lobules VI-VII) and amygdala. Effects were sex- and dose-specific in the regions of interests. Overall, FM 550 exposure resulted in reduced numbers of microglia in most regions examined, with the 1000 µg FM 550 exposed males particularly affected. To further quantify differences in microglia morphology in the 1000 µg FM 550 group, Sholl and skeleton analysis were carried out on individual microglia. Microglia from control females had a more ramified phenotype compared to control males while 1000 µg FM 550-exposed males had decreased branching and ramification compared to same-sex controls. Future studies will examine the impact on the exposure to FM 550 on microglia during development given the critical role of these cells in shaping neural circuits.
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Affiliation(s)
- William P Marinello
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, USA
| | | | - Marley J Fanning
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, USA
| | - Lacey B Malinsky
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, USA
| | - Cassie L Rhodes
- 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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11
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Cunha SC, Menezes-Sousa D, Mello FV, Miranda JAT, Fogaca FHS, Alonso MB, Torres JPM, Fernandes JO. Survey on endocrine-disrupting chemicals in seafood: Occurrence and distribution. ENVIRONMENTAL RESEARCH 2022; 210:112886. [PMID: 35150711 DOI: 10.1016/j.envres.2022.112886] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/31/2022] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
Currently, the presence of endocrine disrupting chemicals (EDCs) in the marine environment pose а potential risk to both wildlife and human health. The occurrence of EDCs in seafood depends of several factors such as source and amounts of EDCs that reach the aquatic environment, physicochemical features of EDCs, and its accumulation in trophic chain. This review highlights the occurrence and distribution of EDCs along the seafood in the last 6 years. The following EDCs were included in this review: brominated flame retardants (PBDEs, PBBs, HBCDDs, TBBPA, and novel flame retardants); pharmaceuticals (paracetamol, ibuprofen, diclofenac, carbamazepine), bisphenols, hormones, personal care products (Musk and UV Filters), and pesticides (organochlorides, organophosphates, and pyrethroids). Some of them were found above the threshold that may cause negative effects on human, animal, and environmental health. More control in some countries, as well as new legislation and inspection over the purchase, sale, use, and production of these compounds, are urgently needed. This review provides data to support risk assessment and raises critical gaps to stimulate and improve future research.
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Affiliation(s)
- Sara C Cunha
- LAQV-REQUIMTE, Laboratory of Bromatology and Hydrology, Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313, Porto, Portugal.
| | - Dhoone Menezes-Sousa
- LAQV-REQUIMTE, Laboratory of Bromatology and Hydrology, Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313, Porto, Portugal; Micropollutants Laboratory Jan Japenga, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro. Av. Carlos Chagas Filho, 373 - CCS - Bl. G, 21941-902, Rio de Janeiro, RJ, Brazil
| | - Flávia V Mello
- LAQV-REQUIMTE, Laboratory of Bromatology and Hydrology, Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313, Porto, Portugal; Micropollutants Laboratory Jan Japenga, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro. Av. Carlos Chagas Filho, 373 - CCS - Bl. G, 21941-902, Rio de Janeiro, RJ, Brazil
| | - Joyce A T Miranda
- LAQV-REQUIMTE, Laboratory of Bromatology and Hydrology, Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313, Porto, Portugal; Micropollutants Laboratory Jan Japenga, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro. Av. Carlos Chagas Filho, 373 - CCS - Bl. G, 21941-902, Rio de Janeiro, RJ, Brazil
| | - Fabiola H S Fogaca
- Bioacessiblity Laboratory, Embrapa Agroindustria de Alimentos, Av. Das Americas, 29501, 23020-470, Guaratiba, Rio de Janeiro, RJ, Brazil
| | - Mariana B Alonso
- Micropollutants Laboratory Jan Japenga, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro. Av. Carlos Chagas Filho, 373 - CCS - Bl. G, 21941-902, Rio de Janeiro, RJ, Brazil
| | - João Paulo M Torres
- Micropollutants Laboratory Jan Japenga, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal Do Rio de Janeiro. Av. Carlos Chagas Filho, 373 - CCS - Bl. G, 21941-902, Rio de Janeiro, RJ, Brazil
| | - José O Fernandes
- LAQV-REQUIMTE, Laboratory of Bromatology and Hydrology, Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313, Porto, Portugal
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12
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Liu S, Song G, Li F, Li R, Chen X, Guo Y, Zhou F, Wang Q, Yang L, Zhou B. Bis (2-ethylhexyl)-2,3,4,5-tetrabromophthalate showed poor penetrability but increased the permeability of blood brain barrier: Evidences from in vitro and in vivo studies. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127386. [PMID: 34879576 DOI: 10.1016/j.jhazmat.2021.127386] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/27/2021] [Accepted: 09/27/2021] [Indexed: 06/13/2023]
Abstract
Bis(2ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH), a replacement for restricted flame retardants, has become ubiquitous in the environment. To reveal the neurotoxicity and underlying mechanism of TBPH, we first evaluated its penetrability through the blood-brain barrier (BBB) using hCMEC/D3 cells as in vitro model, and found TBPH had poor penetrability through BBB with a maximum Papp of 14.8 × 10-6 cms-1. Further study using transgenetic zebrafish (Tg flk1: EGFP) as in vivo model confirmed that TBPH could affect the BBB permeability, probably via affecting the transcription of genes encoding tight junction proteins. Finally, wild type zebrafish embryos/larvae were exposed to TBPH to evaluate the neurotoxicity. The neurodevelopment, neurotransmitters and locomotor activity of zebrafish larvae did not changed, which may be because TBPH can hardly cross the BBB to pose direct exposure to the central nervous system. However, the transcription of opsins genes and visual response to light stimulation in zebrafish larvae were inhibited, pointing to additional mechanism that may cause visual impairment indirectly. Above all, these results can help further understand the neurotoxicity and underlying mechanism by TBPH, and also pointed out potential risk of this chemical to aquatic organisms.
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Affiliation(s)
- Sitian Liu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Guili Song
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
| | - Fan Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Ruiwen Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China; Ecological Environment Monitoring and Scientific Research Center, Changjiang River Basin Ecological Environment Administration, Ministry of Ecology and Environment, Wuhan 430014, PR China
| | - Xiangping Chen
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
| | - Yongyong Guo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
| | - Fang Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
| | - Qiangwei Wang
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310058, PR China
| | - Lihua Yang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China.
| | - Bingsheng Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China
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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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14
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Gillera SEA, Marinello WP, Cao KT, Horman BM, Stapleton HM, Patisaul HB. Sex-specific Disruption of the Prairie Vole Hypothalamus by Developmental Exposure to a Flame Retardant Mixture. Endocrinology 2021; 162:6285199. [PMID: 34038511 PMCID: PMC8571712 DOI: 10.1210/endocr/bqab100] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Indexed: 02/07/2023]
Abstract
Prevalence of neurodevelopmental disorders (NDDs) with social deficits is conspicuously rising, particularly in boys. Flame retardants (FRs) have long been associated with increased risk, and prior work by us and others in multiple species has shown that developmental exposure to the common FR mixture Firemaster 550 (FM 550) sex-specifically alters socioemotional behaviors including anxiety and pair bond formation. In rats, FRs have also been shown to impair aspects of osmoregulation. Because vasopressin (AVP) plays a role in both socioemotional behavior and osmotic balance we hypothesized that AVP and its related nonapeptide oxytocin (OT) would be vulnerable to developmental FM 550 exposure. We used the prairie vole (Microtus ochrogaste) to test this because it is spontaneously prosocial. Using siblings of prairie voles used in a prior study that assessed behavioral deficits resulting from developmental FM 550 exposure across 3 doses, here we tested the hypothesis that FM 550 sex-specifically alters AVP and OT neuronal populations in critical nuclei, such as the paraventricular nucleus (PVN), that coordinate those behaviors, as well as related dopaminergic (determined by tyrosine hydroxylase (TH) immunolabeling) populations. Exposed females had fewer AVP neurons in the anterior PVN and more A13 TH neurons in the zona incerta than controls. By contrast, in FM 550 males, A13 TH neuron numbers in the zona incerta were decreased but only in 1 dose group. These results expand on previous work showing evidence of endocrine disruption of OT/AVP pathways, including to subpopulations of PVN AVP neurons that coordinate osmoregulatory functions in the periphery.
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Affiliation(s)
| | - William P Marinello
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, USA
| | - Kevin T Cao
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, USA
| | - Brian M Horman
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, USA
| | - Heather M Stapleton
- Nicholas School of the Environment, Levine Science Research Center, Duke University, Durham, NC 27710, USA
| | - Heather B Patisaul
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, USA
- Center for Human Health and the Environment, NC State University, Raleigh NC 27695, USA
- Correspondence: Heather B Patisaul, Professor of Biological Sciences, NC State University, 127 David Clark Labs, Raleigh, NC 27695, USA. E-mail:
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15
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Yan H, Hales BF. Effects of an Environmentally Relevant Mixture of Organophosphate Esters Derived From House Dust on Endochondral Ossification in Murine Limb Bud Cultures. Toxicol Sci 2021; 180:62-75. [PMID: 33367866 PMCID: PMC7916738 DOI: 10.1093/toxsci/kfaa180] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Organophosphate esters (OPEs) are used widely as flame retardants and plasticizers but much remains unknown about their potential toxicity. Previously, we reported that 4 individual OPEs suppress endochondral ossification in murine limb bud cultures. However, real-life exposure is to complex OPE mixtures. In the present study, we tested the hypothesis that a Canadian household dust-based OPE mixture will affect endochondral ossification in gestation day 13 CD1 mouse embryo limb buds expressing fluorescent markers for the major cell populations involved in the process: collagen type II alpha 1-enhanced cyan fluorescent protein (proliferative chondrocytes), collagen type X alpha 1-mCherry (hypertrophic chondrocytes), and collagen type I alpha 1-yellow fluorescent protein (osteoblasts). Limbs were cultured for 6 days in the presence of vehicle or dilutions of the OPE mixture (1/1 000 000, 1/600 000, and 1/300 000). All 3 OPE mixture dilutions affected cartilage template development and the progression of endochondral ossification, as indicated by the fluorescent markers. The expression of Sox9, the master regulator of chondrogenesis, was unchanged, but the expression of Runx2 and Sp7, which drive chondrocyte hypertrophy and osteoblastogenesis, was dilution-dependently suppressed. RNA-seq revealed that exposure to the 1/300 000 dilution of the OPE mixture for 24 h downregulated 153 transcripts and upregulated 48 others by at least 1.5-fold. Downregulated transcripts were enriched for those related to the immune system and bone formation. In contrast, upregulated transcripts were enriched for those with stress response functions known to be regulated by ATF4 activation. Thus, exposure to the mixture of OPEs commonly found in house dust may have adverse effects on bone formation.
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Affiliation(s)
- Han Yan
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Barbara F Hales
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
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16
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Dong L, Wang S, Qu J, You H, Liu D. New understanding of novel brominated flame retardants (NBFRs): Neuro(endocrine) toxicity. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 208:111570. [PMID: 33396099 DOI: 10.1016/j.ecoenv.2020.111570] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/22/2020] [Accepted: 10/25/2020] [Indexed: 06/12/2023]
Abstract
Traditional brominated flame retardants (BFRs) negatively affect the environment and human health, especially in the sensitive (developing) nervous system. Considering the physicochemical similarities between novel brominated flame retardants (NBFRs) and BFRs, more and more evidence reveals the neurotoxic effects of NBFRs. We reviewed the neuro(endocrine) toxic effects of NBFRs in vivo and in vitro and discussed their action mechanisms based on the available information. The neurotoxic potential of NBFRs has been demonstrated through direct neurotoxicity and disruption of the neuroendocrine system, with adverse effects on neurobehavioral and reproductive development. Mechanistic studies have shown that the impact of NBFRs is related to the complex interaction of neural and endocrine signals. From disrupting the gender differentiation of the brain, altering serum thyroid/sex hormone levels, gene/protein expression, and so on, to interfere with the feedback effect between different levels of the HPG/HPT axis. In this paper, the mechanism of neurotoxic effects of NBFRs is explored from a new perspective-neuro and endocrine interactions. Gaps in the toxicity data of NBFRs in the neuroendocrine system are supplemented and provide a broader dataset for a complete risk assessment.
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Affiliation(s)
- Liying Dong
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Shutao Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Jinze Qu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Hong You
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai 264209, China.
| | - Dongmei Liu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
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17
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Hogberg HT, de Cássia da Silveira E Sá R, Kleensang A, Bouhifd M, Cemiloglu Ulker O, Smirnova L, Behl M, Maertens A, Zhao L, Hartung T. Organophosphorus flame retardants are developmental neurotoxicants in a rat primary brainsphere in vitro model. Arch Toxicol 2021; 95:207-228. [PMID: 33078273 PMCID: PMC7811506 DOI: 10.1007/s00204-020-02903-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/02/2020] [Indexed: 12/26/2022]
Abstract
Due to regulatory bans and voluntary substitutions, halogenated polybrominated diphenyl ether (PBDE) flame retardants (FR) are increasingly substituted by mainly organophosphorus FR (OPFR). Leveraging a 3D rat primary neural organotypic in vitro model (rat brainsphere), we compare developmental neurotoxic effects of BDE-47-the most abundant PBDE congener-with four OPFR (isopropylated phenyl phosphate-IPP, triphenyl phosphate-TPHP, isodecyl diphenyl phosphate-IDDP, and tricresyl phosphate (also known as trimethyl phenyl phosphate)-TMPP). Employing mass spectroscopy-based metabolomics and transcriptomics, we observe at similar human-relevant non-cytotoxic concentrations (0.1-5 µM) stronger developmental neurotoxic effects by OPFR. This includes toxicity to neurons in the low µM range; all FR decrease the neurotransmitters glutamate and GABA (except BDE-47 and TPHP). Furthermore, n-acetyl aspartate (NAA), considered a neurologic diagnostic molecule, was decreased by all OPFR. At similar concentrations, the FR currently in use decreased plasma membrane dopamine active transporter expression, while BDE-47 did not. Several findings suggest astrogliosis induced by the OPFR, but not BDE-47. At the 5 µM concentrations, the OPFR more than BDE-47 interfered with myelination. An increase of cytokine gene and receptor expressions suggests that exposure to OPFR may induce an inflammatory response. Pathway/category overrepresentation shows disruption in 1) transmission of action potentials, cell-cell signaling, synaptic transmission, receptor signaling, (2) immune response, inflammation, defense response, (3) cell cycle and (4) lipids metabolism and transportation. Taken together, this appears to be a case of regretful substitution with substances not less developmentally neurotoxic in a primary rat 3D model.
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Affiliation(s)
- Helena T Hogberg
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - Rita de Cássia da Silveira E Sá
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Department of Physiology and Pathology, Federal University of Paraíba, João Pessoa, Brazil
| | - Andre Kleensang
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Mounir Bouhifd
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Ozge Cemiloglu Ulker
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Department of Toxicology, Faculty of Pharmacy, Ankara University, Ankara, Turkey
| | - Lena Smirnova
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Mamta Behl
- National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, USA
| | - Alexandra Maertens
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Liang Zhao
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Bloomberg~Kimmel Institute for Cancer Immunotherapy, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Thomas Hartung
- Center for Alternatives To Animal Testing (CAAT), Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- CAAT-Europe, University of Konstanz, Konstanz, Germany
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18
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Witchey SK, Al Samara L, Horman BM, Stapleton HM, Patisaul HB. Perinatal exposure to FireMaster® 550 (FM550), brominated or organophosphate flame retardants produces sex and compound specific effects on adult Wistar rat socioemotional behavior. Horm Behav 2020; 126:104853. [PMID: 32949556 PMCID: PMC7726037 DOI: 10.1016/j.yhbeh.2020.104853] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/31/2020] [Accepted: 09/10/2020] [Indexed: 12/11/2022]
Abstract
Firemaster 550 (FM550) is a flame retardant (FR) mixture that has become one of the most commonly used FRs in household items such as foam-based furniture and baby products. Because this mixture readily leaches from products, contamination of the environment and human tissues is widespread. Prior work by us and others has reported sex-specific behavioral deficits in rodents and zebrafish following early life exposure. In an effort to understand the mechanisms by which these behavioral effects occur, here we explored the effects of its constituents on behavioral outcomes previously shown to be altered by developmental FM550 exposure. The FM550 commercial mixture is composed of two brominated compounds (BFR) and two organophosphate compounds (OPFRs) at almost equivalent proportions. Both the BFR and the OPFR components are differentially metabolized and structurally distinct, but similar to known neurotoxicants. Here we examined adult Wistar rat offspring socioemotional behaviors following perinatal exposure (oral, to the dam) to vehicle, 2000 μg/day FM550, 1000 μg/day BFR or 1000 μg/day OPFR from gestation day 0 to weaning. Beginning on postnatal day 65 offspring from all groups were subjected to a series of behavioral tasks including open field, elevated plus maze, marble burying, social interaction tests, and running wheel. Effects were exposure-, sex- and task-specific, with BFR exposure resulting in the most consistent behavioral deficits. Overall, exposed females showed more deficits compared to males across all dose groups and tasks. These findings help elucidate how different classes of flame retardants, independently and as a mixture, contribute to sex-specific behavioral effects of exposure.
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Affiliation(s)
- Shannah K Witchey
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, United States of America; Center for Human Health and the Environment, NC State University, Raleigh, NC 27695, United States of America
| | - Loujain Al Samara
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, United States of America
| | - Brian M Horman
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, United States of America
| | - Heather M Stapleton
- Nicholas School of the Environment, Levine Science Research Center, Duke University, Durham, NC 27710, United States of America
| | - Heather B Patisaul
- Department of Biological Sciences, NC State University, Raleigh, NC 27695, United States of America; Center for Human Health and the Environment, NC State University, Raleigh, NC 27695, United States of America.
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19
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Oliveri AN, Knuth M, Glazer L, Bailey J, Kullman SW, Levin ED. Zebrafish show long-term behavioral impairments resulting from developmental vitamin D deficiency. Physiol Behav 2020; 224:113016. [PMID: 32561170 PMCID: PMC7737556 DOI: 10.1016/j.physbeh.2020.113016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/09/2020] [Accepted: 06/15/2020] [Indexed: 11/16/2022]
Abstract
Vitamin D has been shown in a wide variety of species to play critical roles in neurodevelopment. Vitamin D deficiency disrupts development of the brain and can cause lasting behavioral dysfunction. Zebrafish have become an important model for the study of development in general and neurodevelopment in particular. Zebrafish were used in the current study to characterize the effects of developmental vitamin D deficiency on behavioral function. Adult zebrafish that had been chronically fed a vitamin D deficient or replete diets were bred and the offspring were continued on those diets. The offspring were behaviorally tested as adults. In the novel tank diving test the vitamin D deficient diet significantly lowered the vertical position of fish indicative of more anxiety-like behavior. In the novel tank diving test swimming activity was also significantly decreased by vitamin D deficiency. Startle response was increased by developmental vitamin D deficiency during the early part of the test. No significant effects of vitamin D deficiency were seen with social affiliation and predatory stimulus avoidance tests. These results indicate a phenotype of vitamin D deficiency characterized by more anxiety-like behavior. This result was relatively specific inasmuch as few or no behavioral effects were seen in other behavioral tests.
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Affiliation(s)
| | - Megan Knuth
- Toxicology Program, North Carolina State University, Raleigh, NC, USA
| | - Lilah Glazer
- Duke University Medical Center, Box 104790, Durham 27710, NC, USA
| | - Jordan Bailey
- Duke University Medical Center, Box 104790, Durham 27710, NC, USA
| | - Seth W Kullman
- Toxicology Program, North Carolina State University, Raleigh, NC, USA; Center for Human Heath and the Environment, North Carolina State University, Raleigh, NC, USA
| | - Edward D Levin
- Duke University Medical Center, Box 104790, Durham 27710, NC, USA.
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20
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Rock KD, St Armour G, Horman B, Phillips A, Ruis M, Stewart AK, Jima D, Muddiman DC, Stapleton HM, Patisaul HB. Effects of Prenatal Exposure to a Mixture of Organophosphate Flame Retardants on Placental Gene Expression and Serotonergic Innervation in the Fetal Rat Brain. Toxicol Sci 2020; 176:203-223. [PMID: 32243540 PMCID: PMC7357193 DOI: 10.1093/toxsci/kfaa046] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
There is a growing need to understand the potential neurotoxicity of organophosphate flame retardants (OPFRs) and plasticizers because use and, consequently, human exposure, is rapidly expanding. We have previously shown in rats that developmental exposure to the commercial flame retardant mixture Firemaster 550 (FM 550), which contains OPFRs, results in sex-specific behavioral effects, and identified the placenta as a potential target of toxicity. The placenta is a critical coordinator of fetal growth and neurodevelopment, and a source of neurotransmitters for the developing brain. We have shown in rats and humans that flame retardants accumulate in placental tissue, and induce functional changes, including altered neurotransmitter production. Here, we sought to establish if OPFRs (triphenyl phosphate and a mixture of isopropylated triarylphosphate isomers) alter placental function and fetal forebrain development, with disruption of tryptophan metabolism as a primary pathway of interest. Wistar rat dams were orally exposed to OPFRs (0, 500, 1000, or 2000 μg/day) or a serotonin (5-HT) agonist 5-methoxytryptamine for 14 days during gestation and placenta and fetal forebrain tissues collected for analysis by transcriptomics and metabolomics. Relative abundance of genes responsible for the transport and synthesis of placental 5-HT were disrupted, and multiple neuroactive metabolites in the 5-HT and kynurenine metabolic pathways were upregulated. In addition, 5-HTergic projections were significantly longer in the fetal forebrains of exposed males. These findings suggest that OPFRs have the potential to impact the 5-HTergic system in the fetal forebrain by disrupting placental tryptophan metabolism.
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Affiliation(s)
- Kylie D Rock
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina 27619
| | - Genevieve St Armour
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina 27619
| | - Brian Horman
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina 27619
| | - Allison Phillips
- Nicholas School of the Environment, Duke University, Durham, North Carolina 27708
| | - Matthew Ruis
- Nicholas School of the Environment, Duke University, Durham, North Carolina 27708
| | - Allison K Stewart
- Molecular Education, Technology, and Research Innovation Center, North Carolina State University, Raleigh, North Carolina 27695
| | - Dereje Jima
- Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina 27695
- Bioinformatics Research Center, North Carolina State University, Raleigh, North Carolina 27695
| | - David C Muddiman
- Molecular Education, Technology, and Research Innovation Center, North Carolina State University, Raleigh, North Carolina 27695
| | - Heather M Stapleton
- Nicholas School of the Environment, Duke University, Durham, North Carolina 27708
| | - Heather B Patisaul
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina 27619
- Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina 27695
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21
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Blum A, Behl M, Birnbaum L, Diamond ML, Phillips A, Singla V, Sipes NS, Stapleton HM, Venier M. Organophosphate Ester Flame Retardants: Are They a Regrettable Substitution for Polybrominated Diphenyl Ethers? ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS 2019; 6:638-649. [PMID: 32494578 PMCID: PMC7269169 DOI: 10.1021/acs.estlett.9b00582] [Citation(s) in RCA: 311] [Impact Index Per Article: 62.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
As the use of polybrominated diphenyl ethers (PBDEs), and the entire class of organohalogen flame retardants, is declining, the use of organophosphate esters flame retardants (OPFRs) is increasing. In this paper, we ask whether OPFRs are a better choice than PBDEs. To address this question, we compared OPFRs with PBDEs for a wide range of properties. OPFRs exposure is ubiquitous in people and in outdoor and indoor environments, and are now often found at higher levels compared to PBDE peak exposure levels. Furthermore, data from toxicity testing, epidemiological studies, and risk assessments all suggest that there are health concerns at current exposure levels for both halogenated and non-halogenated OPFRs. Obtaining the scientific evidence needed for regulation of OPFRs can take many years. Given the large number of OPFRs in use, manufacturers can move towards healthier and safer products by developing innovative ways to reduce fire hazard for electronics enclosures, upholstered furniture, building materials and other consumer products without adding flame retardant chemicals.
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Affiliation(s)
- Arlene Blum
- Green Science Policy Institute, Berkeley, CA, 94709, and Department of Chemistry, UC Berkeley, Berkeley CA 94705
| | - Mamta Behl
- National Toxicology Program, NIEHS, Research Triangle Park, NC 27709
| | - Linda Birnbaum
- National Cancer Institute at NIEHS, Research Triangle Park, NC 27709
| | - Miriam L. Diamond
- Department of Earth Sciences, University of Toronto, Ontario, Toronto, Canada M5S 3B1
| | - Allison Phillips
- Risk Assessment and Natural Resource Sciences Inc., Arcadis, Raleigh, NC 27607
| | - Veena Singla
- Program on Reproductive Health and the Environment, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, CA 94143
| | - Nisha S Sipes
- National Toxicology Program, NIEHS, Research Triangle Park, NC 27709
| | | | - Marta Venier
- O’ Neill School of Public and Environmental Affairs, Indiana University, Bloomington, IN 47401
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22
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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: 29] [Impact Index Per Article: 5.8] [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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23
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Geng Y, Peterson RT. The zebrafish subcortical social brain as a model for studying social behavior disorders. Dis Model Mech 2019; 12:dmm039446. [PMID: 31413047 PMCID: PMC6737945 DOI: 10.1242/dmm.039446] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Social behaviors are essential for the survival and reproduction of social species. Many, if not most, neuropsychiatric disorders in humans are either associated with underlying social deficits or are accompanied by social dysfunctions. Traditionally, rodent models have been used to model these behavioral impairments. However, rodent assays are often difficult to scale up and adapt to high-throughput formats, which severely limits their use for systems-level science. In recent years, an increasing number of studies have used zebrafish (Danio rerio) as a model system to study social behavior. These studies have demonstrated clear potential in overcoming some of the limitations of rodent models. In this Review, we explore the evolutionary conservation of a subcortical social brain between teleosts and mammals as the biological basis for using zebrafish to model human social behavior disorders, while summarizing relevant experimental tools and assays. We then discuss the recent advances gleaned from zebrafish social behavior assays, the applications of these assays to studying related disorders, and the opportunities and challenges that lie ahead.
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Affiliation(s)
- Yijie Geng
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, 30 S. 2000 East, Salt Lake City, UT 84112, USA
| | - Randall T Peterson
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, 30 S. 2000 East, Salt Lake City, UT 84112, USA
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24
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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 PMCID: PMC9524722 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] [MESH Headings] [Grants] [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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25
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Doherty BT, Hoffman K, Keil AP, Engel SM, Stapleton HM, Goldman BD, Olshan AF, Daniels JL. Prenatal exposure to organophosphate esters and cognitive development in young children in the Pregnancy, Infection, and Nutrition Study. ENVIRONMENTAL RESEARCH 2019; 169:33-40. [PMID: 30408751 PMCID: PMC6347494 DOI: 10.1016/j.envres.2018.10.033] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 10/26/2018] [Accepted: 10/27/2018] [Indexed: 05/20/2023]
Abstract
Organophosphate esters (OPEs) are a class of chemicals commonly used as flame retardants and plasticizers. OPEs are applied to a wide variety of consumer products and have a propensity to leach from these products. Consequently, OPEs are ubiquitous contaminants in many human environments and human exposure is pervasive. Accumulating evidence suggests that OPEs are capable of interfering with childhood cognitive development through both neurologic- and endocrine-mediated mechanisms. However, observational evidence of cognitive effects is limited. We used data collected in the third phase of the Pregnancy, Infection, and Nutrition Study to investigate cognitive effects of prenatal exposure to OPEs. In a spot prenatal maternal urine sample, we measured the following OPE metabolites: diphenyl phosphate (DPHP), bis(1,3-dichloro-2-propyl phosphate) (BDCIPP), isopropyl-phenyl phenyl phosphate (ip-PPP), and 1-hydroxyl-2-propyl bis(1-chloro-2-propyl) phosphate (BCIPHIPP). We assessed children's language and multi-faceted and overall cognitive development between two and three years of age using the MacArthur-Bates Communicative Development Inventories (MB-CDI) and the Mullen Scales of Early Learning (MSEL). We used linear regression to estimate the change in children's scores on these developmental assessments per interquartile range (IQR) increase in log-transformed, specific-gravity-corrected prenatal OPE metabolite concentrations, adjusted for maternal age, education, income, race/ethnicity, BMI, and child's sex. A total of 149 children had both OPE metabolite measurements and MB-CDI scores, and 227 children had both OPE metabolite measurements and MSEL scores. We observed that higher concentrations of ip-PPP (ng/ml) were associated with lower scores on the MSEL Cognitive Composite Score (β = -2.61; 95% CI: -5.69, 0.46), and separately on two of the four MSEL Scales that comprise the Cognitive Composite, specifically the Fine Motor Scale (β = -3.08; 95% CI: -5.26, -0.91) and the Expressive Language Scale (β = -1.21; 95% CI: -2.91, 0.49). We similarly observed that prenatal ip-PPP concentrations were inversely associated with age-standardized scores on the MB-CDI Vocabulary assessment (β = -1.19; 95% CI: -2.53, 0.16). Other OPE metabolites were not strongly associated with performance on either assessment. Our results suggest that isopropylated triarylphosphate isomers, the presumed parent compounds of ip-PPP, may adversely impact cognitive development, including fine motor skills and early language abilities. Our study contributes to the growing body of observational evidence that suggests prenatal exposure to OPEs may adversely affect cognitive development.
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Affiliation(s)
- Brett T Doherty
- Department of Epidemiology, University of North Carolina at Chapel Hill, 135 Dauer Drive, 2101 McGavran-Greenberg Hall, Chapel Hill, NC 27599, USA.
| | - Kate Hoffman
- Nicholas School of the Environment, Duke University, 9 Circuit Drive, Box 27708, Durham, NC 27708, USA
| | - Alexander P Keil
- Department of Epidemiology, University of North Carolina at Chapel Hill, 135 Dauer Drive, 2101 McGavran-Greenberg Hall, Chapel Hill, NC 27599, USA
| | - Stephanie M Engel
- Department of Epidemiology, University of North Carolina at Chapel Hill, 135 Dauer Drive, 2101 McGavran-Greenberg Hall, Chapel Hill, NC 27599, USA
| | - Heather M Stapleton
- Nicholas School of the Environment, Duke University, 9 Circuit Drive, Box 27708, Durham, NC 27708, USA
| | - Barbara D Goldman
- Frank Porter Graham Child Development Institute & Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill, CB 8180, Chapel Hill, NC 27599, USA
| | - Andrew F Olshan
- Department of Epidemiology, University of North Carolina at Chapel Hill, 135 Dauer Drive, 2101 McGavran-Greenberg Hall, Chapel Hill, NC 27599, USA
| | - Julie L Daniels
- Department of Epidemiology, University of North Carolina at Chapel Hill, 135 Dauer Drive, 2101 McGavran-Greenberg Hall, Chapel Hill, NC 27599, USA
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26
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Alzualde A, Behl M, Sipes NS, Hsieh JH, Alday A, Tice RR, Paules RS, Muriana A, Quevedo C. Toxicity profiling of flame retardants in zebrafish embryos using a battery of assays for developmental toxicity, neurotoxicity, cardiotoxicity and hepatotoxicity toward human relevance. Neurotoxicol Teratol 2018; 70:40-50. [PMID: 30312655 DOI: 10.1016/j.ntt.2018.10.002] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/03/2018] [Accepted: 10/08/2018] [Indexed: 01/02/2023]
Abstract
Following the voluntary phase-out of brominated flame retardants (BFRs) due to their environmental persistence and toxicity, the organophosphorus flame retardants (OPFRs) are emerging replacements. However, there is limited information on the potential human health effects of the OPFRs. Zebrafish embryos are a viable vertebrate model organism with many advantages for high throughput testing toward human hazard assessment. We utilized zebrafish embryos to assess developmental toxicity, neurotoxicity, cardiotoxicity and hepatotoxicity, of eight replacement OPFRs: (triphenyl phosphate [TPHP], isopropylated phenyl phosphate [IPP], 2-ethylhexyl diphenyl phosphate [EHDP], tert-butylated phenyl diphenyl phosphate [BPDP], trimethyl phenyl phosphate [TMPP], isodecyl diphenyl phosphate [IDDP], tris(1,3-dichloroisopropyl) phosphate [TDCIPP], and tris(2-chloroethyl) phosphate [TCEP]) and two BFRs (3,3',5,5'- tetrabromobisphenol A [TBBPA] and 2,2'4,4'-brominated diphenyl ether [BDE-47]). To determine potential effects on teratogenicity, embryos were exposed to flame retardants (FRs) at 4 h post fertilization (hpf) to 4 days post fertilization (dpf) and morphological alterations and corresponding survival were evaluated at 2 and 4 dpf. Internal concentrations were measured in larvae used in this assay by liquid chromatography-mass spectrometry. Locomotor activity was assessed in larvae treated for 48 h (from 3 dpf to 5 dpf), followed by hepatotoxicity evaluation. Finally, alterations in heart rate and rhythmicity were assessed to determine cardiotoxicity in 48 hpf embryos exposed to compounds for 3 h. Results suggest that several OPFRs (BPDP, EHDP; IPP, TMPP; TPHP and TDCIPP) produced adverse effects in multiple target organs at concentrations comparable to the two BFRs. As these OPFRs have the capacity to disrupt an integrated vertebrate model, they potentially have the capacity to affect mammalian biology. Then, we compared the lowest effective levels (LEL) in zebrafish with estimated or measured human plasma concentrations using biomonitoring data (human plasma, breast milk, handwipe samples and house dust) and a high throughput toxicokinetic (HTTK) model. Results indicate that for some compounds, the nominal LELs were within the range of human exposures, while internal LELs in zebrafish are above internal exposures in humans. These findings demonstrate the value of the zebrafish model as a relevant screening tool and support the need for further hazard characterization of the OPFRs.
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Affiliation(s)
| | - Mamta Behl
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, United States of America
| | - Nisha S Sipes
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, United States of America
| | - Jui-Hua Hsieh
- Kelly Government Solutions, Research Triangle Park, NC, United States of America
| | | | - Raymond R Tice
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, United States of America
| | - Richard S Paules
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, United States of America
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27
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Glazer L, Hawkey AB, Wells CN, Drastal M, Odamah KA, Behl M, Levin ED. Developmental Exposure to Low Concentrations of Organophosphate Flame Retardants Causes Life-Long Behavioral Alterations in Zebrafish. Toxicol Sci 2018; 165:487-498. [PMID: 29982741 PMCID: PMC6154272 DOI: 10.1093/toxsci/kfy173] [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: 02/05/2023] Open
Abstract
As the older class of brominated flame retardants (BFRs) are phased out of commercial use because of findings of neurotoxicity with developmental exposure, a newer class of flame retardants have been introduced, the organophosphate flame retardants (OPFRs). Presently, little is known about the potential for developmental neurotoxicity or the behavioral consequences of OPFR exposure. Our aim was to characterize the life-long neurobehavioral effects of 4 widely used OPFRs using the zebrafish model. Zebrafish embryos were exposed to 0.1% DMSO (vehicle control); or one of the following treatments; isopropylated phenyl phosphate (IPP) (0.01, 0.03, 0.1, 0.3 µM); butylphenyl diphenyl phosphate (BPDP) (0.003, 0.03, 0.3, 3 µM); 2-ethylhexyl diphenyl phosphate (EHDP) (0.03, 0.3, 1 µM); isodecyl diphenyl phosphate (IDDP) (0.1, 0.3, 1, 10 µM) from 0- to 5-days postfertilization. On Day 6, the larvae were tested for motility under alternating dark and light conditions. Finally, at 5-7 months of age the exposed fish and controls were tested on a battery of behavioral tests to assess emotional function, sensorimotor response, social interaction and predator evasion. These tests showed chemical-specific short-term effects of altered motility in larvae in all of the tested compounds, and long-term impairment of anxiety-related behavior in adults following IPP, BPDP, or EHDP exposures. Our results show that OPFRs may not be a safe alternative to the phased-out BFRs and may cause behavioral impacts throughout the lifespan. Further research should evaluate the risk to mammalian experimental models and humans.
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Affiliation(s)
- Lilah Glazer
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina 27710
| | - Andrew B Hawkey
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina 27710
| | - Corinne N Wells
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina 27710
| | - Meghan Drastal
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina 27710
| | - Kathryn-Ann Odamah
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina 27710
| | - Mamta Behl
- Toxicology Branch, National Toxicology Program Division, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina, 27709
| | - Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina 27710
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28
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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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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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Gray WA, Billock VA. Developmental neurotoxicity and autism: A potential link between indoor neuroactive pollutants and the curious birth order risk factor. Int J Dev Neurosci 2017; 62:32-36. [DOI: 10.1016/j.ijdevneu.2017.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 07/24/2017] [Accepted: 07/24/2017] [Indexed: 11/16/2022] Open
Affiliation(s)
- Wesley A. Gray
- Department of PediatricsUniversity of Toledo Medical School, Health Science CampusPediatric Pharmacology Research CenterToledoOH43614United States
| | - Vincent A. Billock
- College of Optometry and Center for Cognitive & Brain Sciences, Ohio State University338 W. 10th Ave.ColumbusOH43210United States
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Haggard DE, Das SR, Tanguay RL. Comparative Toxicogenomic Responses to the Flame Retardant mITP in Developing Zebrafish. Chem Res Toxicol 2016; 30:508-515. [PMID: 27957850 DOI: 10.1021/acs.chemrestox.6b00423] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Monosubstituted isopropylated triaryl phosphate (mITP) is a major component of Firemaster 550, an additive flame retardant mixture commonly used in polyurethane foams. Developmental toxicity studies in zebrafish established mITP as the most toxic component of FM 550, which causes pericardial edema and heart looping failure. Mechanistic studies showed that mITP is an aryl hydrocarbon receptor (AhR) ligand; however, the cardiotoxic effects of mITP were independent of the AhR. We performed comparative whole genome transcriptomics in wild-type and ahr2hu3335 zebrafish, which lack functional ahr2, to identify transcriptional signatures causally involved in the mechanism of mITP-induced cardiotoxicity. Regardless of ahr2 status, mITP exposure resulted in decreased expression of transcripts related to the synthesis of all-trans-retinoic acid and a host of Hox genes. Clustered gene ontology enrichment analysis showed unique enrichment in biological processes related to xenobiotic metabolism and response to external stimuli in wild-type samples. Transcript enrichments overlapping both genotypes involved the retinoid metabolic process and sensory/visual perception biological processes. Examination of the gene-gene interaction network of the differentially expressed transcripts in both genetic backgrounds demonstrated a strong AhR interaction network specific to wild-type samples, with overlapping genes regulated by retinoic acid receptors (RARs). A transcriptome analysis of control ahr2-null zebrafish identified potential cross-talk among AhR, Nrf2, and Hif1α. Collectively, we confirmed that mITP is an AhR ligand and present evidence in support of our hypothesis that mITP's developmental cardiotoxic effects are mediated by inhibition at the RAR level.
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Affiliation(s)
- Derik E Haggard
- Department of Environmental and Molecular Toxicology, Oregon State University , Corvallis, Oregon 97333, United States
| | - Siba R Das
- Pacific Northwest Diabetes Research Institute , Seattle, Washington 98122, United States
| | - Robert L Tanguay
- Department of Environmental and Molecular Toxicology, Oregon State University , Corvallis, Oregon 97333, United States
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Usenko CY, Abel EL, Hopkins A, Martinez G, Tijerina J, Kudela M, Norris N, Joudeh L, Bruce ED. Evaluation of Common Use Brominated Flame Retardant (BFR) Toxicity Using a Zebrafish Embryo Model. TOXICS 2016; 4:E21. [PMID: 29051424 PMCID: PMC5606660 DOI: 10.3390/toxics4030021] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/16/2016] [Accepted: 08/16/2016] [Indexed: 11/16/2022]
Abstract
Brominated flame retardants (BFRs) are used to reduce the flammability of plastics, textiles, and electronics. BFRs vary in their chemical properties and structures, and it is expected that these differences alter their biological interactions and toxicity. Zebrafish were used as the model organism for assessing the toxicity of nine structurally-diverse BFRs. In addition to monitoring for overt toxicity, the rate of spontaneous movement, and acetylcholinesterase and glutathione-S-transferase (GST) activities were assessed following exposure. The toxicities of BFRs tested can be ranked by LC50 as tetrabromobisphenol A (TBBPA) < 4,4'-isopropylidenebis[2-(2,6-dibromophenoxyl)ethanol] (TBBPA-OHEE) < Pentabromochlorocyclohexane (PBCH) < 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB) < hexabromocyclododecane (HBCD) < hexabromobenzene (HBB) < Tetrabromophthalic anhydride (PHT4). No adverse effect was observed in di(2-ethylhexyl) tetrabromophthalate (TBPH) or dibromoneopentyl glycol (DBNPG)-treated embryos. The rate of spontaneous movement was decreased in a concentration-dependent manner following exposure to four of the nine compounds. GST activity was elevated following treatment with PBCH, TBBPA, HBCD, and HBB. The results indicate that exposure to several BFRs may activate an antioxidant response and alter behavior during early development. Some of the BFRs, such as TBBPA and TBBPA-OHEE, induced adverse effects at concentrations lower than chemicals that are currently banned. These results suggest that zebrafish are sensitive to exposure to BFRs and can be used as a comparative screening model, as well as to determine alterations in behavior following exposure and probe mechanisms of action.
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Affiliation(s)
- Crystal Y. Usenko
- Department of Biology, Baylor University, Waco, TX 76798, USA; (E.L.A.); (A.H.); (G.M.); (M.K.); (N.N.); (L.J.)
| | - Erika L. Abel
- Department of Biology, Baylor University, Waco, TX 76798, USA; (E.L.A.); (A.H.); (G.M.); (M.K.); (N.N.); (L.J.)
| | - Aaron Hopkins
- Department of Biology, Baylor University, Waco, TX 76798, USA; (E.L.A.); (A.H.); (G.M.); (M.K.); (N.N.); (L.J.)
| | - Gerardo Martinez
- Department of Biology, Baylor University, Waco, TX 76798, USA; (E.L.A.); (A.H.); (G.M.); (M.K.); (N.N.); (L.J.)
| | - Jonathan Tijerina
- Department of Biology, Baylor University, Waco, TX 76798, USA; (E.L.A.); (A.H.); (G.M.); (M.K.); (N.N.); (L.J.)
- School of Medicine, Stanford University, Palo Alto, CA 94305, USA;
| | - Molly Kudela
- Department of Biology, Baylor University, Waco, TX 76798, USA; (E.L.A.); (A.H.); (G.M.); (M.K.); (N.N.); (L.J.)
| | - Nick Norris
- Department of Biology, Baylor University, Waco, TX 76798, USA; (E.L.A.); (A.H.); (G.M.); (M.K.); (N.N.); (L.J.)
| | - Lana Joudeh
- Department of Biology, Baylor University, Waco, TX 76798, USA; (E.L.A.); (A.H.); (G.M.); (M.K.); (N.N.); (L.J.)
| | - Erica D. Bruce
- Department of Environmental Science, Baylor University, Waco, TX 76798, USA;
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Sterling ME, Chang GQ, Karatayev O, Chang SY, Leibowitz SF. Effects of embryonic ethanol exposure at low doses on neuronal development, voluntary ethanol consumption and related behaviors in larval and adult zebrafish: Role of hypothalamic orexigenic peptides. Behav Brain Res 2016; 304:125-38. [PMID: 26778786 DOI: 10.1016/j.bbr.2016.01.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 12/03/2015] [Accepted: 01/05/2016] [Indexed: 12/28/2022]
Abstract
Embryonic exposure to ethanol is known to affect neurochemical systems in rodents and increase alcohol drinking and related behaviors in humans and rodents. With zebrafish emerging as a powerful tool for uncovering neural mechanisms of numerous diseases and exhibiting similarities to rodents, the present report building on our rat studies examined in zebrafish the effects of embryonic ethanol exposure on hypothalamic neurogenesis, expression of orexigenic neuropeptides, and voluntary ethanol consumption and locomotor behaviors in larval and adult zebrafish, and also effects of central neuropeptide injections on these behaviors affected by ethanol. At 24h post-fertilization, zebrafish embryos were exposed for 2h to ethanol, at low concentrations of 0.25% and 0.5%, in the tank water. Embryonic ethanol compared to control dose-dependently increased hypothalamic neurogenesis and the proliferation and expression of the orexigenic peptides, galanin (GAL) and orexin (OX), in the anterior hypothalamus. These changes in hypothalamic peptide neurons were accompanied by an increase in voluntary consumption of 10% ethanol-gelatin and in novelty-induced locomotor and exploratory behavior in adult zebrafish and locomotor activity in larvae. After intracerebroventricular injection, these peptides compared to vehicle had specific effects on these behaviors altered by ethanol, with GAL stimulating consumption of 10% ethanol-gelatin more than plain gelatin food and OX stimulating novelty-induced locomotor behavior while increasing intake of food and ethanol equally. These results, similar to those obtained in rats, suggest that the ethanol-induced increase in genesis and expression of these hypothalamic peptide neurons contribute to the behavioral changes induced by embryonic exposure to ethanol.
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Affiliation(s)
- M E Sterling
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY, United States
| | - G-Q Chang
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY, United States
| | - O Karatayev
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY, United States
| | - S Y Chang
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY, United States
| | - S F Leibowitz
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY, United States.
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