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Schrenk D, Bignami M, Bodin L, Chipman JK, del Mazo J, Grasl‐Kraupp B, Hogstrand C, (Ron) Hoogenboom L, Leblanc J, Nebbia CS, Nielsen E, Ntzani E, Petersen A, Sand S, Schwerdtle T, Wallace H, Benford D, Fürst P, Hart A, Rose M, Schroeder H, Vrijheid M, Ioannidou S, Nikolič M, Bordajandi LR, Vleminckx C. Update of the risk assessment of polybrominated diphenyl ethers (PBDEs) in food. EFSA J 2024; 22:e8497. [PMID: 38269035 PMCID: PMC10807361 DOI: 10.2903/j.efsa.2024.8497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024] Open
Abstract
The European Commission asked EFSA to update its 2011 risk assessment on polybrominated diphenyl ethers (PBDEs) in food, focusing on 10 congeners: BDE-28, -47, -49, -99, -100, -138, -153, -154, -183 and ‑209. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour and reproductive/developmental effects are the critical effects in rodent studies. For four congeners (BDE-47, -99, -153, -209) the Panel derived Reference Points, i.e. benchmark doses and corresponding lower 95% confidence limits (BMDLs), for endpoint-specific benchmark responses. Since repeated exposure to PBDEs results in accumulation of these chemicals in the body, the Panel estimated the body burden at the BMDL in rodents, and the chronic intake that would lead to the same body burden in humans. For the remaining six congeners no studies were available to identify Reference Points. The Panel concluded that there is scientific basis for inclusion of all 10 congeners in a common assessment group and performed a combined risk assessment. The Panel concluded that the combined margin of exposure (MOET) approach was the most appropriate risk metric and applied a tiered approach to the risk characterisation. Over 84,000 analytical results for the 10 congeners in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary Lower Bound exposure to PBDEs were meat and meat products and fish and seafood. Taking into account the uncertainties affecting the assessment, the Panel concluded that it is likely that current dietary exposure to PBDEs in the European population raises a health concern.
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Wang D, Yuan Q, Liu S, Zhao P, Liang C, Ma Y, Li S, Zhu X, Hao X, Shi J, Fan H. BDE-47 flame retardant exposure induces microglial pyroptosis and cognitive deficits by activating the mtROS-NLRP3 axis via Sirt3 downregulation and is salvaged by honokiol. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 334:122158. [PMID: 37429494 DOI: 10.1016/j.envpol.2023.122158] [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: 05/06/2023] [Revised: 06/23/2023] [Accepted: 07/06/2023] [Indexed: 07/12/2023]
Abstract
The brominated flame retardant 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) is widely distributed in the environment and poses a certain risk to human health. Studies have reported that oxidative stress is a key mechanism underlying BDE-47-induced neurotoxicity. Mitochondrial reactive oxygen species (mtROS) is a crucial mediator of NLRP3 inflammasome activation, which is involved in cognitive dysfunction induced by environmental toxins. However, the function of the mtROS-NLRP3 inflammasome pathway in BDE-47-elicited cognitive deficits and the underlying mechanisms remain elusive. Our data illustrated that eight weeks of BDE-47 (20 mg/kg) gavage led to cognitive deficits and hippocampal neuronal injury in mice. BDE-47 exposure downregulated Sirt3 expression and decreased the activity and expression level of SOD2, thereby inhibiting mtROS scavenging and activating NLRP3 inflammasome-mediated pyroptosis in the mouse hippocampus and BV-2 cells. In vitro, BDE-47-evoked microglial pyroptosis relied on NLRP3 inflammasome activation. Moreover, a mtROS scavenger (TEMPO) attenuated NLRP3 inflammasome activation and subsequent microglial pyroptosis under BDE-47 stress. Furthermore, Sirt3 overexpression restored the activity and expression of SOD2 and enhanced mtROS scavenging, thereby suppressing NLRP3 inflammasome activation and ameliorating microglial pyroptosis. Notably, honokiol (HKL), a pharmacological agonist of Sirt3, mitigated BDE-47-evoked hippocampal neuronal injury and cognitive impairment by inhibiting mtROS-NLRP3 axis-mediated pyroptosis via Sirt3 upregulation.
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Affiliation(s)
- Dongmei Wang
- College of Basic Medicine and Forensic Medicine, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, China
| | - Quan Yuan
- College of Basic Medicine and Forensic Medicine, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, China; Henan Province Rongkang Hospital, Luoyang, China
| | - Shuwen Liu
- College of Basic Medicine and Forensic Medicine, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, China
| | - Pu Zhao
- College of Basic Medicine and Forensic Medicine, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, China
| | - Chen Liang
- College of Basic Medicine and Forensic Medicine, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, China
| | - Yilu Ma
- College of Basic Medicine and Forensic Medicine, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, China
| | - Sanqiang Li
- College of Basic Medicine and Forensic Medicine, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, China
| | - Xiaoying Zhu
- College of Basic Medicine and Forensic Medicine, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, China
| | - Xueqin Hao
- College of Basic Medicine and Forensic Medicine, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, China
| | - Jian Shi
- College of Basic Medicine and Forensic Medicine, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, China
| | - Hua Fan
- College of Basic Medicine and Forensic Medicine, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, China.
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The association between prenatal concentrations of polybrominated diphenyl ether and child cognitive and psychomotor function. Environ Epidemiol 2021; 5:e156. [PMID: 34131617 PMCID: PMC8196085 DOI: 10.1097/ee9.0000000000000156] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 04/09/2021] [Indexed: 11/25/2022] Open
Abstract
Previous studies suggest a negative association between prenatal polybrominated diphenyl ethers (PBDEs) exposure and child cognitive and psychomotor development. However, the timing of the relationship between PBDE exposure and neurodevelopment is still unclear. We examined the association between PBDE concentration at two different prenatal times (early and late pregnancy) and cognitive function in children 6-8 years of age. Methods Eight hundred pregnant women were recruited between 2007 and 2009 from Sherbrooke, Canada. Four PBDE congeners (BDE-47, -99, -100, and -153) were measured in maternal plasma samples collected during early pregnancy (12 weeks of gestation) and at delivery. At 6-8 years of age, 355 children completed a series of subtests spanning multiple neuropsychologic domains: verbal and memory skills were measured using the Wechsler Intelligence Scale for Children, Fourth Edition; visuospatial processing using both Wechsler Intelligence Scale for Children, Fourth Edition and Neuropsychological Assessment second edition; and attention was assessed through the Test of Everyday Attention for Children. Additionally, parents completed subtests from the Developmental Coordination Disorder Questionnaire to measure child motor control. We used linear regression and quantile g-computation models to estimate associations of PBDE congener concentrations and psychologic test scores. Results In our models, no significant associations were detected between PBDE mixture and any of the child psychologic scores. BDE-99 concentration at delivery was nominally associated with higher scores on short-term and working memory while a decrease in spatial perception and reasoning was nominally associated with higher BDE-100 concentration at delivery. Conclusion Overall, our results did not show a significant association between PBDEs and child cognitive and motor development.
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Shi P, Wan Y, Grandjean A, Lee JM, Tay CY. Clarifying the in-situ cytotoxic potential of electronic waste plastics. CHEMOSPHERE 2021; 269:128719. [PMID: 33127117 DOI: 10.1016/j.chemosphere.2020.128719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/13/2020] [Accepted: 10/20/2020] [Indexed: 06/11/2023]
Abstract
Plastics in waste electronics (E-plastics) account for approximately 20% of the entire global electronic waste (E-waste) stream. Most of the E-plastics are not recycled as the presence of toxic additives (e.g. heavy metals, brominated flame retardants (BFRs), antimony, etc.) have associated environmental and health concerns. However, the majority of the studies are focused on quantitative assessment of the toxic constituents in E-plastics, while empirical information regarding the potential toxic effects in humans is largely lacking. To gain a deeper appreciation into the toxicological profile of E-plastics, in situ time-dependent exposures of 6 different human cell lines to a panel of 8 representative E-plastics recovered from liquid crystal displays (LCD), keyboards, screen frames, and wire insulators were conducted. Although several hazardous elements (e.g. Pb, As, Sb, Zn, Cu, etc) were detected at concentrations that far exceed the limit values permitted by the Restriction of Hazardous Substances Directive and EU Directives in the panel E-plastics, in-depth analysis of the 144 unique cell viability data points and live-dead staining experiments suggest that the acute and sub-chronic toxic effects of E-plastics in direct contact with human cells are negligible. These observations agreed with the inductively coupled plasma-optical emission spectrometry data, which revealed that leaching of these toxic additives into the biological milieu is not sufficiently high to trigger a cytotoxic response up to a continuous culture period of 2 weeks. The novel insights gained from this study are posited to further clarify the uncertainty associated with the safety and circular economy implementation of E-plastics.
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Affiliation(s)
- Pujiang Shi
- Energy Research Institute, Nanyang Technological University, 1 Cleantech Loop, 637141, Singapore
| | - Yan Wan
- Energy Research Institute, Nanyang Technological University, 1 Cleantech Loop, 637141, Singapore
| | | | - Jong-Min Lee
- Energy Research Institute, Nanyang Technological University, 1 Cleantech Loop, 637141, Singapore; School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Dr, 637459, Singapore
| | - Chor Yong Tay
- Energy Research Institute, Nanyang Technological University, 1 Cleantech Loop, 637141, Singapore; School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Dr, 637551, Singapore.
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Giulivo M, Suciu NA, Eljarrat E, Gatti M, Capri E, Barcelo D. Ecological and human exposure assessment to PBDEs in Adige River. ENVIRONMENTAL RESEARCH 2018; 164:229-240. [PMID: 29501833 DOI: 10.1016/j.envres.2018.02.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 01/12/2018] [Accepted: 02/15/2018] [Indexed: 06/08/2023]
Abstract
The interest for environmental issues and the concern resulting from the potential exposure to contaminants were the starting point to develop methodologies in order to evaluate the consequences that those might have over both the environment and human health. Considering the feature of POPs, including PBDEs, such as bioaccumulation, biomagnification, long-range transport and adverse effects even long time after exposure, risk assessment of POPs requires specific approaches and tools. In this particular context, the MERLIN-Expo tool was used to assess the aquatic environmental exposure of Adige River to PBDEs and the accumulation of PBDEs in humans through the consumption of possible contaminated local aquatic food. The aquatic food web models provided as output of the deterministic simulation the time trend of concentrations for twenty years of BDE-47 and total PBDEs, expressed using the physico-chemical properties of BDE-47, in aquatic organisms of the food web of Adige River. For BDE-47, the highest accumulated concentrations were detected for two benthic species: Thymallus thymallus and Squalius cephalus whereas the lowest concentrations were obtained for the pelagic specie Salmo trutta marmoratus. The trend obtained for the total PBDEs, calculated using the physico-chemical properties of BDE-47, follows the one of BDE-47. For human exposure, different BDE-47 and total PBDEs concentration trends between children, adolescent, adults and elderly were observed, probably correlated with the human intake of fish products in the daily diet and the ability to metabolize these contaminants. In detail, for the adolescents, adults and elderly a continuous accumulation of the target contaminants during the simulation's years was observed, whereas for children a plateau at the end of the simulation period was perceived.
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Affiliation(s)
- Monica Giulivo
- Dipartment for Sustainable Food Process, Università Cattolica del Sacro Cuore di Piacenza, Via Emilia Parmense 84, 29100 Piacenza, Italy
| | - Nicoleta Alina Suciu
- Dipartment for Sustainable Food Process, Università Cattolica del Sacro Cuore di Piacenza, Via Emilia Parmense 84, 29100 Piacenza, Italy
| | - Ethel Eljarrat
- Water and Soil Quality Research Group, Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Marina Gatti
- Dipartment for Sustainable Food Process, Università Cattolica del Sacro Cuore di Piacenza, Via Emilia Parmense 84, 29100 Piacenza, Italy
| | - Ettore Capri
- Dipartment for Sustainable Food Process, Università Cattolica del Sacro Cuore di Piacenza, Via Emilia Parmense 84, 29100 Piacenza, Italy
| | - Damia Barcelo
- Water and Soil Quality Research Group, Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain; Catalan Institute for Water Research (ICRA), H(2)O Building, Scientific and Technological Park of the University of Girona, Emili Grahit 101, 17003 Girona, Spain
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Zhuang J, Wang S, Shan Q, Zhang ZF, Li MQ, Zheng GH, Fan SH, Wu DM, Hu B, Lu J, Zheng YL. Adeno-associated virus vector-mediated expression of DJ-1 attenuates learning and memory deficits in 2, 2´, 4, 4´-tetrabromodiphenyl ether (BDE-47)-treated mice. JOURNAL OF HAZARDOUS MATERIALS 2018; 347:390-402. [PMID: 29335220 DOI: 10.1016/j.jhazmat.2018.01.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 12/18/2017] [Accepted: 01/03/2018] [Indexed: 06/07/2023]
Abstract
Evidence indicates that oxidative stress is the central pathological feature of 2, 2´, 4, 4´-tetrabromodiphenyl ether (BDE-47)-induced neurotoxicity. Protein kinase C delta (PKCδ), an oxidative stress-sensitive kinase, can be proteolytically cleaved to yield a catalytically active fragment (PKCδ-CF) that is involved in various neurodegenerative disorders. Here, we showed that BDE-47 treatment increased ROS, malondialdehyde, and protein carbonyl levels in the mouse hippocampus. In turn, excessive ROS induced caspase-3-dependent PKCδ activation and stimulated NF-κB p65 nuclear translocation, resulting in inflammation in the mouse hippocampus. These changes caused learning and memory deficits in BDE-47-treated mice. Treatment with Z-DEVD-fmk, a caspase-3 inhibitor, or N-acetyl-L-cysteine, an antioxidant, blocked PKCδ activation and subsequently inhibited inflammation, thereby improving learning and memory deficits in BDE-47-treated mice. Our data further showed that activation of ROS-PKCδ signaling was associated with DJ-1 downregulation, which exerted neuroprotective effects against oxidative stress induced by different neurotoxic agents. Adeno-associated viral vector-mediated DJ-1 overexpression in the hippocampus effectively inhibited excessive ROS production, suppressed caspase-3-dependent PKCδ cleavage, blunted inflammation and ultimately reversed learning and memory deficits in BDE-47-treated mice. Taken together, our results demonstrate that DJ-1 plays a pivotal role in BDE-47-induced neurotoxic effects and learning and memory deficits.
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Affiliation(s)
- Juan Zhuang
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, Jiangsu Province, China; Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huaiyin Normal University, Huaian 223300, China; Jiangsu Key Laboratory for Eco-Agricultural Biotechnology around Hongze Lake, Huaiyin Normal University, Huaian 223300, China; School of Life Sciences, Huaiyin Normal University, Huaian 223300, China
| | - Shan Wang
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Qun Shan
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, Jiangsu Province, China; Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Zi-Feng Zhang
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Meng-Qiu Li
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Gui-Hong Zheng
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Shao-Hua Fan
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Dong-Mei Wu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China.
| | - Bin Hu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Jun Lu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China.
| | - Yuan-Lin Zheng
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China.
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Dingemans MML, Kock M, van den Berg M. Mechanisms of Action Point Towards Combined PBDE/NDL-PCB Risk Assessment. Toxicol Sci 2018; 153:215-24. [PMID: 27672163 DOI: 10.1093/toxsci/kfw129] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
At present, human risk assessment of the structurally similar non-dioxin-like (NDL) PCBs and polybrominated diphenylethers (PBDEs) is done independently for both groups of compounds. There are however obvious similarities between NDL-PCBs and PBDEs with regard to modulation of the intracellular calcium homeostasis (basal calcium levels, voltage-gated calcium channels, calcium uptake, ryanodine receptor) and thyroid hormone (TH) homeostasis (TH levels and transport). which are mechanisms of action related to neurobehavioral effects (spontaneous activity, habituation and learning ability). There also similarities in agonistic interactions with the hepatic nuclear receptors PXR and CAR. Several effects on developmental (reproductive) processes have also been observed, but results were more dispersed and insufficient to compare both groups of compounds. The available mechanistic information is sufficient to warrant a dose addition model for NDL-PCBs and PBDEs, including their hydroxylated metabolites.Although many of the observed effects are similar from a qualitative point of view for both groups, congener or tissue specific differences have also been found. As this is a source of uncertainty in the combined hazard and risk assessment of these compounds, molecular entities involved in the observed mechanisms and adverse outcomes associated with these compounds need to be identified. The systematical generation of (quantitative) structure-activity information for NDL-PCBs and PBDEs on these targets (including potential non-additive effects) will allow a more realistic risk estimation associated with combined exposure to both groups of compounds during early life. Additional validation studies are needed to quantify these uncertainties for risk assessment of NDL-PCBs and PBDEs.
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Affiliation(s)
- Milou M L Dingemans
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Marjolijn Kock
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Martin van den Berg
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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Chen J, Li X, Li X, Chen D. The environmental pollutant BDE-209 regulates NO/cGMP signaling through activation of NMDA receptors in neurons. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:3397-3407. [PMID: 29151189 DOI: 10.1007/s11356-017-0651-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 10/31/2017] [Indexed: 06/07/2023]
Abstract
The common flame retardant decabrominated diphenyl ether (BDE-209) is a persistent organic pollutant. Epidemiological studies have revealed that prenatal or postnatal exposure to BDE-209 can result in delayed cognitive development, and BDE-209 has been shown to be toxic to cultured neurons with maturation interference effects. However, its neurotoxic mechanism remains unclear. Nitric oxide/cyclic guanosine monophosphate (NO/cGMP) signaling plays an important role in regulating neuronal maturation. We examined the influence of BDE-209 (100, 200, and 400 nM) on NO production and cGMP levels signaling in rodent neurons in vitro, with or without pretreatment N-methyl-D-aspartate (NMDA) receptor antagonism. We found that nanomolar concentrations of BDE-209 affected levels of the second messengers NO and cGMP, and that these effects could be blocked by NMDA receptor antagonism. Moreover, BDE-209 activation of NMDA receptors inhibited the expression of phosphodiesterases (PDEs), which modulate intracellular cGMP levels, and increased the Bcl-2/Bax ratio, favoring apoptosis induction. Our studies implicate the NMDA-NO/cGMP pathway in the pathogenic mechanism through which BDE-209 induces neurotoxicity.
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Affiliation(s)
- Jingsi Chen
- Department of Fetal Medicine and Prenatal Diagnosis, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China
- Obstetrics & Gynecology Institute of Guangzhou, Guangzhou, 510150, China
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Guangzhou, People's Republic of China, Guangzhou, 510150, China
- Key Laboratories for Major Obstetric Diseases of Guangdong Province, Guangzhou, 510150, China
| | - Xiuying Li
- Obstetrics & Gynecology Institute of Guangzhou, Guangzhou, 510150, China
| | - Xiaomei Li
- Obstetrics & Gynecology Institute of Guangzhou, Guangzhou, 510150, China
| | - Dunjin Chen
- Obstetrics & Gynecology Institute of Guangzhou, Guangzhou, 510150, China.
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Guangzhou, People's Republic of China, Guangzhou, 510150, China.
- Key Laboratories for Major Obstetric Diseases of Guangdong Province, Guangzhou, 510150, China.
- , No.63, Duobao Road, Guangzhou, 510150, China.
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Xiong L, Liyue H, Fancai Z, Maoting L, Ya L, Ting H, Zhen Y, Shanshan Z, Wenwen G, Yan T. Effect of decabrominated diphenyl ether exposure on spatial learning and memory, the expression and phosphorylation of hippocampal glutamate receptor subunits in adult Sprague-Dawley rats. J Toxicol Sci 2018; 43:645-657. [DOI: 10.2131/jts.43.645] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Li Xiong
- School of Public Health, Southwest Medical University, China
| | - Hao Liyue
- School of Public Health, Southwest Medical University, China
| | - Zeng Fancai
- Department of Biochemistry and Molecular Biology, Southwest Medical University, China
| | - Li Maoting
- School of Public Health, Southwest Medical University, China
| | - Li Ya
- School of Public Health, Southwest Medical University, China
| | - He Ting
- School of Public Health, Southwest Medical University, China
| | - Yang Zhen
- School of Public Health, Southwest Medical University, China
| | - Zhu Shanshan
- School of Public Health, Southwest Medical University, China
| | - Gu Wenwen
- School of Public Health, Southwest Medical University, China
| | - Tang Yan
- School of Public Health, Southwest Medical University, China
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Zhuang J, Wen X, Zhang YQ, Shan Q, Zhang ZF, Zheng GH, Fan SH, Li MQ, Wu DM, Hu B, Lu J, Zheng YL. TDP-43 upregulation mediated by the NLRP3 inflammasome induces cognitive impairment in 2 2',4,4'-tetrabromodiphenyl ether (BDE-47)-treated mice. Brain Behav Immun 2017; 65:99-110. [PMID: 28532818 DOI: 10.1016/j.bbi.2017.05.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/10/2017] [Accepted: 05/19/2017] [Indexed: 10/19/2022] Open
Abstract
It is now commonly known that exposure to polybrominated diphenyl ethers (PBDEs) may cause neurotoxicity and cognitive deficits in children as well as adults, but the underlying mechanisms are still not clear. In the present study, we aimed to elucidate the potential underlying mechanism of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47)-induced neurotoxicity and cognitive impairment. Our results showed that BDE-47-treated mice exhibited impaired cognition and robust upregulation of nuclear TDP-43 in the hippocampus. Hippocampus-specific TDP-43 knockdown attenuated hippocampal apoptosis, restored synaptic protein levels and thus improved cognitive dysfunction in BDE-47-treated mice. Furthermore, our data demonstrated that NLRP3 inflammasome activation played a distinct role in the upregulation of nuclear TDP-43 by downregulating Parkin in the hippocampus of BDE-47-treated mice. Knocking down NLRP3 in the hippocampus or inhibiting caspase 1 activity in BDE-47-treated mice effectively increased Parkin expression in the hippocampus, which decreased the levels of nuclear TDP-43 and ultimately abrogated TDP-43-induced neurotoxic effects. Taken together, our data indicate that TDP-43 upregulation mediated by NLRP3 inflammasome activation via Parkin downregulation in the hippocampus induces cognitive decline in BDE-47-treated mice, and suggest that inhibition of NLRP3 or TDP-43 may be a potential strategy for the prevention or treatment of cognitive impairment in BDE-47-induced neurotoxicity and brain diseases.
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Affiliation(s)
- Juan Zhuang
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, Jiangsu Province, PR China; Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China; Jiangsu Key Laboratory for Eco-Agricultural Biotechnology around Hongze Lake, School of Life Science, Huaiyin Normal University, 111 Changjiang Road, Huaian 223300, Jiangsu Province, PR China
| | - Xin Wen
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Yan-Qiu Zhang
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, Jiangsu Province, PR China
| | - Qun Shan
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, Jiangsu Province, PR China; Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Zi-Feng Zhang
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Gui-Hong Zheng
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Shao-Hua Fan
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Meng-Qiu Li
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Dong-Mei Wu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Bin Hu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Jun Lu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China.
| | - Yuan-Lin Zheng
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China.
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Fournier K, Baumont E, Glorennec P, Bonvallot N. Relative toxicity for indoor semi volatile organic compounds based on neuronal death. Toxicol Lett 2017; 279:33-42. [PMID: 28709981 DOI: 10.1016/j.toxlet.2017.07.875] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 07/03/2017] [Accepted: 07/09/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND Semi Volatile Organic Compounds (SVOCs) are contaminants commonly found in dwellings as a result of their use as plasticizers, flame retardants, or pesticides in building materials and consumer products. Many SVOCs are suspected of being neurotoxic, based on mammal experimentation (impairment of locomotor activity, spatial learning/memory or behavioral changes), raising the question of cumulative risk assessment. The aim of this work is to estimate the relative toxicity of such SVOCs, based on neuronal death. METHOD SVOCs fulfilling the following conditions were included: detection frequency >10% in dwellings, availability of data on effects or mechanism of action for neurotoxicity, and availability of dose-response relationships based on cell viability assays as a proxy of neuronal death. Benchmark concentration values (BMC) were estimated using a Hill model, and compared to assess relative toxicity. RESULTS Of the 58 SVOCs selected, 28 were suspected of being neurotoxic in mammals, and 21 have been documented as inducing a decrease in cell viability in vitro. 13 have at least one dose-response relationship that can be used to derive a BMC based on a 10% fall in neuronal viability. Based on this in vitro endpoint, PCB-153 appeared to be the most toxic compound, having the lowest BMC10 (0.072μM) and diazinon the least toxic compound, having the highest BMC10 (94.35μM). We showed that experimental designs (in particular choice of cell lines) had a significant influence on BMC calculation. CONCLUSION For the first time, the relative in vitro toxicity of 13 indoor contaminants belonging to different chemical families has been assessed on the basis of neuronal cell viability. Lack of comparable toxicity datasets limits the number of SVOCs that can be included. More standardized protocols in terms of cell lines, species and exposure duration should be developed with a view to cumulative risk assessment.
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Affiliation(s)
- Kevin Fournier
- EHESP School of Public Health, Sorbonne Paris Cité, Avenue du Professeur Léon Bernard, 35043 Rennes Cedex, France; INSERM UMR1085 IRSET (Research Institute in Environmental and Occupational Health), Rennes, France.
| | - Emmanuel Baumont
- EHESP School of Public Health, Sorbonne Paris Cité, Avenue du Professeur Léon Bernard, 35043 Rennes Cedex, France; INSERM UMR1085 IRSET (Research Institute in Environmental and Occupational Health), Rennes, France.
| | - Philippe Glorennec
- EHESP School of Public Health, Sorbonne Paris Cité, Avenue du Professeur Léon Bernard, 35043 Rennes Cedex, France; INSERM UMR1085 IRSET (Research Institute in Environmental and Occupational Health), Rennes, France.
| | - Nathalie Bonvallot
- EHESP School of Public Health, Sorbonne Paris Cité, Avenue du Professeur Léon Bernard, 35043 Rennes Cedex, France; INSERM UMR1085 IRSET (Research Institute in Environmental and Occupational Health), Rennes, France.
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12
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Pham-Lake C, Aronoff EB, Camp CR, Vester A, Peters SJ, Caudle WM. Impairment in the mesohippocampal dopamine circuit following exposure to the brominated flame retardant, HBCDD. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2017; 50:167-174. [PMID: 28214749 PMCID: PMC5382642 DOI: 10.1016/j.etap.2017.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 02/03/2017] [Indexed: 06/06/2023]
Abstract
Many chemicals have been used to increase the safety of consumer products by reducing their flammability and risk for ignition. Recent focus on brominated flame retardants, such as polybrominated diphenyl ethers (PBDEs) has shown them to contribute to neurobehavioral deficits in children, including learning and memory. As the manufacture and use of PBDEs have been reduced, replacement chemicals, such as hexabromocyclododecane (HBCDD) have been substituted. Our current study evaluated the neurotoxicity of HBCDD, concentrating on dopaminergic innervation to the hippocampus. Using an in vivo model, we exposed male mice to HBCDD and then assessed alterations to the dopamine synapse 6 weeks later. These exposures elicited significant reductions in presynaptic dopaminergic proteins, including TH, COMT, MAO-B, DAT, VMAT2, and alpha-synuclein. In contrast, postsynaptic dopamine receptors were not impaired. These findings suggest that the mesohippocampal dopamine circuit is vulnerable to HBCDD and the dopamine terminal may be a selective target for alteration.
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Affiliation(s)
- Camille Pham-Lake
- Department of Environmental Health, Rollins School of Public Health Emory University, Atlanta, GA 30322-3090, USA
| | - Elizabeth B Aronoff
- Department of Environmental Health, Rollins School of Public Health Emory University, Atlanta, GA 30322-3090, USA
| | - Chad R Camp
- Department of Environmental Health, Rollins School of Public Health Emory University, Atlanta, GA 30322-3090, USA
| | - Aimee Vester
- Department of Environmental Health, Rollins School of Public Health Emory University, Atlanta, GA 30322-3090, USA
| | - Sam J Peters
- Department of Environmental Health, Rollins School of Public Health Emory University, Atlanta, GA 30322-3090, USA
| | - W Michael Caudle
- Department of Environmental Health, Rollins School of Public Health Emory University, Atlanta, GA 30322-3090, USA; Center for Neurodegenerative Disease, School of Medicine, Emory University Atlanta, GA 30322-3090, USA.
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13
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Vuong AM, Braun JM, Yolton K, Xie C, Webster GM, Sjödin A, Dietrich KN, Lanphear BP, Chen A. Prenatal and postnatal polybrominated diphenyl ether exposure and visual spatial abilities in children. ENVIRONMENTAL RESEARCH 2017; 153:83-92. [PMID: 27915227 PMCID: PMC5222735 DOI: 10.1016/j.envres.2016.11.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/23/2016] [Accepted: 11/24/2016] [Indexed: 05/22/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) are associated with impaired visual spatial abilities in toxicological studies, but no epidemiologic study has investigated PBDEs and visual spatial abilities in children. The Health Outcomes and Measures of the Environment Study, a prospective birth cohort (2003-2006, Cincinnati, OH), was used to examine prenatal and childhood PBDEs and visual spatial abilities in 199 children. PBDEs were measured at 16±3 weeks gestation and at 1, 2, 3, 5, and 8 years using gas chromatography/isotope dilution high-resolution mass spectrometry. We used the Virtual Morris Water Maze to measure visual spatial abilities at 8 years. In covariate-adjusted models, 10-fold increases in BDE-47, -99, and -100 at 5 years were associated with shorter completion times by 5.2s (95% Confidence Interval [CI] -9.3, -1.1), 4.5s (95% CI -8.1, -0.9), and 4.7s (95% CI -9.0, -0.3), respectively. However, children with higher BDE-153 at 3 years had longer completion times (β=5.4s, 95% CI -0.3, 11.1). Prenatal PBDEs were associated with improved visual spatial memory retention, with children spending a higher percentage of their search path in the correct quadrant. Child sex modified some associations between PBDEs and visual spatial learning. Longer path lengths were observed among males with increased BDE-47 at 2 and 3 years, while females had shorter paths. In conclusion, prenatal and postnatal BDE-28, -47, -99, and -100 at 5 and 8 years were associated with improved visual spatial abilities, whereas a pattern of impairments in visual spatial learning was noted with early childhood BDE-153 concentrations.
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Affiliation(s)
- Ann M Vuong
- Division of Epidemiology, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Joseph M Braun
- Department of Epidemiology, Brown University School of Public Health, Providence, RI, USA
| | - Kimberly Yolton
- Division of General and Community Pediatrics, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Changchun Xie
- Division of Biostatistics and Bioinformatics, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Glenys M Webster
- BC Children's Hospital Research Institute, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Andreas Sjödin
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Kim N Dietrich
- Division of Epidemiology, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Bruce P Lanphear
- BC Children's Hospital Research Institute, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Aimin Chen
- Division of Epidemiology, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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14
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Lei ENY, Yau MS, Yeung CC, Murphy MB, Wong KL, Lam MHW. Profiling of Selected Functional Metabolites in the Central Nervous System of Marine Medaka (Oryzias melastigma) for Environmental Neurotoxicological Assessments. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2017; 72:269-280. [PMID: 27990605 DOI: 10.1007/s00244-016-0342-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 12/02/2016] [Indexed: 06/06/2023]
Abstract
The simultaneous profiling of 43 functional metabolites in the brain of the small model vertebrate organism, marine medaka (Oryzais melastigma), has been accomplished via dansyl chloride derivatization and LC-MS/MS quantification. This technique was applied to examine effects of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), one of the most abundant polybrominated diphenyl ether flame retardants in the natural environment, on the central nervous system (CNS) of vertebrates. The model teleosts were fed with bioencapsulated Artemia nauplii for up to 21 days. Multivariate statistical analysis has demonstrated that levels of numerous classical neurotransmitters and their metabolites in the CNS of the fish were perturbed even at the early phase of dietary exposure. Subsequent metabolic pathway analysis further implied potential impairment of the arginine and proline metabolism; glycine, serine and threonine metabolism; D-glutamine and D-glutamate metabolism; alanine, aspartate, and glutamate metabolism; valine, leucine, and isoleucine biosynthesis, and the cysteine and methionine metabolism in the brain of the test organism. Our results demonstrate that targeted profiling of functional metabolites in the CNS may shed light on how the various neurological pathways of vertebrates, including humans, are affected by toxicant/stress exposure.
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Affiliation(s)
- Elva Ngai-Yu Lei
- State Key Laboratory for Marine Pollution, Department of Biology & Chemistry, City University of Hong Kong, Tat Chee Ave., Kowloon, Hong Kong SAR, China
- State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Hong Kong SAR, China
| | - Man-Shan Yau
- State Key Laboratory for Marine Pollution, Department of Biology & Chemistry, City University of Hong Kong, Tat Chee Ave., Kowloon, Hong Kong SAR, China
| | - Chi-Chung Yeung
- State Key Laboratory for Marine Pollution, Department of Biology & Chemistry, City University of Hong Kong, Tat Chee Ave., Kowloon, Hong Kong SAR, China
| | - Margaret B Murphy
- State Key Laboratory for Marine Pollution, Department of Biology & Chemistry, City University of Hong Kong, Tat Chee Ave., Kowloon, Hong Kong SAR, China
| | - Ka-Leung Wong
- State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Hong Kong SAR, China
| | - Michael Hon-Wah Lam
- State Key Laboratory for Marine Pollution, Department of Biology & Chemistry, City University of Hong Kong, Tat Chee Ave., Kowloon, Hong Kong SAR, China.
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15
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Li X, Wang C, Wang W, Yue C, Tang Y. Neonatal exposure to BDE 209 impaired learning and memory, decreased expression of hippocampal core SNAREs and synaptophysin in adult rats. Neurotoxicology 2017; 59:40-48. [PMID: 28104350 DOI: 10.1016/j.neuro.2017.01.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 01/10/2017] [Accepted: 01/10/2017] [Indexed: 12/17/2022]
Abstract
Polybrominated diphenyl ethers (PBDEs) are a class of flame retardants. While the mechanism remains unknown, the potential neurotoxic effects of PBDEs remain a relevant issue. In the present study, neonatal Sprague-Dawley rats of both sexes were administered BDE 209 (1, 10, or 20mg/kg body weight) or peanut oil once daily from postnatal day (PND) 5 to PND 10. We examined the spatial learning and memory by Morris water maze and the working and reference memory by eight-arm radial maze in the stage of adulthood. Compared with controls, significantly longer escape latencies and fewer platform-crossings in the Morris water maze were observed in rats exposed to 1, 10, and 20mg/kg BDE 209, and these effects were dose-dependent. Significantly higher working and reference memory error rates in the eight-arm radial maze were also observed in rats exposed to 10 and 20mg/kg BDE 209. Furthermore, we detected the mRNA and protein expressions of hippocampal synaptobrevin 2, syntaxin 1A, Synaptosome Associated Protein 25 (SNAP-25), and synaptophysin using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blot methods. Compared with controls, the mRNA expressions of synaptobrevin 2, syntaxin 1A, SNAP-25, and synaptophysin were significantly decreased in the hippocampi of rats exposed to 1, 10, and 20 mg/kg BDE 209, and the protein expressions of synaptobrevin 2 and SNAP-25 were significantly decreased in the hippocampi of rats exposed to 10 and 20 mg/kg BDE 209, while syntaxin 1A and synaptophysin were significantly decreased in rats exposed to 1, 10, and 20 mg/kg BDE 209. Alterations that may be involved in the learning and memory deficits induced by BDE 209 reveal the possibility of synapse loss.
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Affiliation(s)
- Xiong Li
- Department of Occupational Medicine, School of Public Health, Southwest Medical University, Luzhou City 646000, PR China
| | - Chunmei Wang
- Experimental Teaching Center, School of Public Health, Southwest Medical University, Luzhou City 646000, PR China
| | - Wen Wang
- Department of Public Health, School of Public Health, Southwest Medical University, Luzhou City 646000, PR China
| | - Chengwei Yue
- Department of Prevention Medicine, School of Public Health, Southwest Medical University, Luzhou City 646000, PR China
| | - Yan Tang
- Experimental Teaching Center, School of Public Health, Southwest Medical University, Luzhou City 646000, PR China.
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16
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Knecht AL, Truong L, Simonich MT, Tanguay RL. Developmental benzo[a]pyrene (B[a]P) exposure impacts larval behavior and impairs adult learning in zebrafish. Neurotoxicol Teratol 2017; 59:27-34. [PMID: 27989697 PMCID: PMC5235990 DOI: 10.1016/j.ntt.2016.10.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 10/18/2016] [Accepted: 10/21/2016] [Indexed: 12/23/2022]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are produced from incomplete combustion of organic materials or fossil fuels, and are present in crude oil and coal; therefore, they are ubiquitous environmental contaminants present in urban air, dust, soil, and water. It is widely recognized that PAHs pose risks to human health, especially for the developing fetus and infant where PAH exposures have been linked to in-utero mortality, cardiovascular effects, and lower intelligence. Using the zebrafish model, we evaluated the developmental toxicity of benzo[a]pyrene (B[a]P). Zebrafish embryos were exposed from 6 to 120h post fertilization (hpf) to 0.4 and 4μM B[a]P. The Viewpoint Zebrabox systems were used to evaluate larval photomotor response (LPR) activity and we identified that exposure to 4μM B[a]P resulted in a hyperactive LPR phenotype. To evaluate the role of aryl hydrocarbon receptor (AHR) in this larval phenotype, we exposed ahr2hu2334 null larvae to 4μM B[a]P. Though ahr2hu2334 larvae did not display hyperactive swimming, these larvae had a decrease in LPR activity, suggesting that AHR2 plays a role in B[a]P induced larval hyperactivity. To determine if developmental B[a]P exposures would produce adult behavioral deficits, a subset of exposed animals was raised to adulthood and tested in a conditioned stimulus test using shuttleboxes. Developmentally exposed B[a]P zebrafish exhibited decreased learning and memory. Together this data demonstrates that developmental B[a]P exposure adversely impacts larval behavior, and learning in adult zebrafish.
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Affiliation(s)
- Andrea L Knecht
- Department of Environmental and Molecular Toxicology, Sinnhuber Aquatic Research Laboratory, Environmental Health Sciences Center, Oregon State University, Corvallis, OR, USA
| | - Lisa Truong
- Department of Environmental and Molecular Toxicology, Sinnhuber Aquatic Research Laboratory, Environmental Health Sciences Center, Oregon State University, Corvallis, OR, USA
| | - Michael T Simonich
- Department of Environmental and Molecular Toxicology, Sinnhuber Aquatic Research Laboratory, Environmental Health Sciences Center, Oregon State University, Corvallis, OR, USA
| | - Robert L Tanguay
- Department of Environmental and Molecular Toxicology, Sinnhuber Aquatic Research Laboratory, Environmental Health Sciences Center, Oregon State University, Corvallis, OR, USA.
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17
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Saquib Q, Siddiqui MA, Ahmed J, Al-Salim A, Ansari SM, Faisal M, Al-Khedhairy AA, Musarrat J, AlWathnani HA, Alatar AA, Al-Arifi SA. Hazards of low dose flame-retardants (BDE-47 and BDE-32): Influence on transcriptome regulation and cell death in human liver cells. JOURNAL OF HAZARDOUS MATERIALS 2016; 308:37-49. [PMID: 26808241 DOI: 10.1016/j.jhazmat.2016.01.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 12/21/2015] [Accepted: 01/10/2016] [Indexed: 06/05/2023]
Abstract
We have evaluated the in vitro low dose hepatotoxic effects of two flame-retardants (BDE-47 and BDE-32) in HepG2 cells. Both congeners declined the viability of cells in MTT and NRU cell viability assays. Higher level of intracellular reactive oxygen species (ROS) and dysfunction of mitochondrial membrane potential (ΔΨm) were observed in the treated cells. Comet assay data confirmed the DNA damaging potential of both congeners. BDE-47 exposure results in the appearance of subG1 apoptotic peak (30.1%) at 100 nM, while BDE-32 arrested the cells in G2/M phase. Among the set of 84 genes, BDE-47 induces downregulation of majority of mRNA transcripts, whilst BDE-32 showed differential expression of transcripts in HepG2. The ultrastructural analysis revealed mitochondrial swelling and degeneration of cristae in BDE-47 and BDE-32 treated cells. Overall our data demonstrated the hepatotoxic potential of both congeners via alteration of vital cellular pathways.
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Affiliation(s)
- Quaiser Saquib
- Zoology Department, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; A.R. Al-Jeraisy Chair for DNA Research, Zoology Department, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
| | - Maqsood A Siddiqui
- Zoology Department, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; A.R. Al-Jeraisy Chair for DNA Research, Zoology Department, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Javed Ahmed
- Zoology Department, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; A.R. Al-Jeraisy Chair for DNA Research, Zoology Department, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Abdullah Al-Salim
- Zoology Department, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; A.R. Al-Jeraisy Chair for DNA Research, Zoology Department, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Sabiha M Ansari
- Department of Botany & Microbiology, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Mohammad Faisal
- Department of Botany & Microbiology, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Abdulaziz A Al-Khedhairy
- Zoology Department, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Javed Musarrat
- Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh 202002, India; Baba Ghulam Shah Badshah University, Rajouri 185131, Jammu and Kashmir, India
| | - Hend A AlWathnani
- Department of Botany & Microbiology, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Abdulrahman A Alatar
- Department of Botany & Microbiology, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Saud A Al-Arifi
- Zoology Department, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
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18
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Role of glutamate receptors in tetrabrominated diphenyl ether (BDE-47) neurotoxicity in mouse cerebellar granule neurons. Toxicol Lett 2015; 241:159-66. [PMID: 26640238 DOI: 10.1016/j.toxlet.2015.11.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 11/25/2015] [Accepted: 11/25/2015] [Indexed: 01/22/2023]
Abstract
The polybrominated diphenyl ether (PBDE) flame retardants are developmental neurotoxicants, as evidenced by numerous in vitro, animal and human studies. PBDEs can alter the homeostasis of thyroid hormone and directly interact with brain cells. Induction of oxidative stress, leading to DNA damage and apoptotic cell death is a prominent mechanism of PBDE neurotoxicity, though other mechanisms have also been suggested. In the present study we investigated the potential role played by glutamate receptors in the in vitro neurotoxicity of the tetrabromodiphenyl ether BDE-47, one of the most abundant PBDE congeners. Toxicity of BDE-47 in mouse cerebellar neurons was diminished by antagonists of glutamate ionotropic receptors, but not by antagonists of glutamate metabotropic receptors. Antagonists of NMDA and AMPA/Kainate receptors also inhibited BDE-47-induced oxidative stress and increases in intracellular calcium. The calcium chelator BAPTA-AM also inhibited BDE-47 cytotoxicity and oxidative stress. BDE-47 caused a rapid increase of extracellular glutamate levels, which was not antagonized by any of the compounds tested. The results suggest that BDE-47, by still unknown mechanisms, increases extracellular glutamate which in turn activates ionotropic glutamate receptors leading to increased calcium levels, oxidative stress, and ultimately cell death.
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Behavioral and thyroid effects of in utero and lactational exposure of Sprague–Dawley rats to the polybrominated diphenyl ether mixture DE71. Neurotoxicol Teratol 2015; 52:127-42. [DOI: 10.1016/j.ntt.2015.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 08/07/2015] [Accepted: 08/08/2015] [Indexed: 12/30/2022]
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Michael Caudle W. This can't be stressed enough: The contribution of select environmental toxicants to disruption of the stress circuitry and response. Physiol Behav 2015; 166:65-75. [PMID: 26409212 DOI: 10.1016/j.physbeh.2015.09.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 09/21/2015] [Accepted: 09/22/2015] [Indexed: 02/06/2023]
Abstract
Integration of the hypothalamic-pituitary-adrenal (HPA) axis and the limbic system through glucocorticoid signaling is imperative in initiating and regulating a suitable stress response following real or perceived threats. Dysfunction of these circuits that results in a persistent or inhibited glucocorticoid secretion can severely affect processing of stressful experiences and lead to risk for developing further psychiatric pathology. Exposure to toxic chemicals found in our environment, including pesticides, metals, and industrial compounds, have been shown to have significant impact on neurological health and disease. Indeed, studies have begun to identify the HPA axis and limbic system as potential targets of many of these environmental chemicals, suggesting a possible environmental risk for damage to the stress circuit and response to stressful stimuli. This review will focus on our current understanding of the impact exposure to environmental toxicants, including bisphenol A and lead, has on the synaptic physiology of the HPA axis and limbic system and how this contributes to an alteration in behavior output. Further, this discussion will provide a starting point to continue to couple novel toxicological and neurological approaches to elaborate our understanding of the influence of environmental chemicals on the stress response and pathology.
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Affiliation(s)
- W Michael Caudle
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322-3090, USA; Center for Neurodegenerative Disease, School of Medicine, Emory University, Atlanta, GA 30322-3090, USA.
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21
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Liu X, Wang J, Lu C, Zhu C, Qian B, Li Z, Liu C, Shao J, Yan J. The role of lysosomes in BDE 47-mediated activation of mitochondrial apoptotic pathway in HepG2 cells. CHEMOSPHERE 2015; 124:10-21. [PMID: 25479806 DOI: 10.1016/j.chemosphere.2014.10.054] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 10/11/2014] [Accepted: 10/14/2014] [Indexed: 06/04/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) are a group of widely used flame retardants. The rising presence of PBDEs in human tissues has received considerable concerns with regard to potential health risks. While the mitochondrial-apoptotic pathway has been suggested in PBDEs-induced apoptosis, the role of lysosomes is yet to be understood. In the present study, HepG2 cells were exposed to BDE 47 at various concentrations and durations to establish the causal and temporal relationships among various cellular events, such as cell viability, reactive oxygen species (ROS), mitochondrial membrane potential (MMP), apoptosis, and expression of cytochrome C and caspase 3. The involvement of lysosomes was simultaneously studied by evaluating lysosomal membrane permeability (LMP) and changes in the expression of cathepsin B, a lysosome hydrolase. In addition, a cathepsin B inhibitor (10 μM CA-074) was used to determine the involvement of lysosomes and potential interactions between lysosomes and mitochondria. Our results showed that ROS production was an initial response of HepG2 to BDE 47 exposure, followed by a decreased MMP; a loss of MMP caused additional ROS generation which acted to induce LMP; an increased LMP resulted in a release of cathepsin B which aggravated the loss of MMP leading to release of cytochrome C and caspase 3 and subsequent apoptosis. Pretreatment with CA-074 did not abolish the initial ROS generation, however, all downstream events were dramatically alleviated. Taken together, our data indicate that lysosomes might be involved in BDE 47-mediated mitochondrial-apoptotic pathway in HepG2 cells, possibly through feedback interactions between mitochondria and lysosomes.
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Affiliation(s)
- Xiaohui Liu
- Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University, Dalian 116044, China
| | - Jian Wang
- Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University, Dalian 116044, China
| | - Chengquan Lu
- Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University, Dalian 116044, China
| | - Chunyan Zhu
- Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University, Dalian 116044, China
| | - Bo Qian
- Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University, Dalian 116044, China
| | - Zhenwei Li
- Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University, Dalian 116044, China
| | - Chang Liu
- Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University, Dalian 116044, China
| | - Jing Shao
- Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University, Dalian 116044, China; Dalian Key Laboratory of Hematology, Department of Hematology, The Second Affiliated Hospital of Dalian Medical University, Institute of Stem Cell Transplantation of Dalian Medical University, Dalian 116027, China.
| | - Jinsong Yan
- Dalian Key Laboratory of Hematology, Department of Hematology, The Second Affiliated Hospital of Dalian Medical University, Institute of Stem Cell Transplantation of Dalian Medical University, Dalian 116027, China.
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22
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Lyche JL, Rosseland C, Berge G, Polder A. Human health risk associated with brominated flame-retardants (BFRs). ENVIRONMENT INTERNATIONAL 2015; 74:170-80. [PMID: 25454234 DOI: 10.1016/j.envint.2014.09.006] [Citation(s) in RCA: 198] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 09/15/2014] [Accepted: 09/16/2014] [Indexed: 05/20/2023]
Abstract
The purposes of this review are to assess the human exposure and human and experimental evidence for adverse effects of brominated flame-retardants (BFRs) with specific focus on intake from seafood. The leakage of BFRs from consumer products leads to exposure of humans from fetal life to adulthood. Fish and fish products contain the highest levels of BFRs and dominate the dietary intake of frequent fish eaters in Europe, while meat, followed by seafood and dairy products accounted for the highest US dietary intake. House dust is also reported as an important source of exposure for children as well as adults. The levels of BFRs in the general North American populations are higher than those in Europe and Japan and the highest levels are detected in infants and toddlers. The daily intake via breast milk exceeds the RfD in 10% of US infants. BFRs including PBDEs, HBCDs and TBBP-A have induced endocrine-, reproductive- and behavior effects in laboratory animals. Furthermore, recent human epidemiological data demonstrated association between exposure to BFRs and similar adverse effects as observed in animal studies. Fish including farmed fish and crude fish oil for human consumption may contain substantial levels of BFRs and infants and toddlers consuming these products on a daily basis may exceed the tolerable daily intake suggesting that fish and fish oil alone represent a risk to human health. This intake comes in addition to exposure from other sources (breast milk, other food, house dust). Because potential harmful concentrations of BFRs and other toxicants occur in fish and fish products, research on a wider range of products is warranted, to assess health hazard related to the contamination of fish and fish products for human consumption.
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Affiliation(s)
- Jan L Lyche
- Norwegian School of Veterinary Science, Department of Food Safety and Infection Biology, P.O. Box 8146 Dep., N-0033 Oslo, Norway.
| | | | - Gunnar Berge
- Pronova BioPharma AS, P.O. Box 420, NO-1327 Lysaker, Norway
| | - Anuschka Polder
- Norwegian School of Veterinary Science, Department of Food Safety and Infection Biology, P.O. Box 8146 Dep., N-0033 Oslo, Norway
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23
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Reverte I, Domingo JL, Colomina MT. Neurodevelopmental effects of decabromodiphenyl ether (BDE-209) in APOE transgenic mice. Neurotoxicol Teratol 2014; 46:10-7. [DOI: 10.1016/j.ntt.2014.08.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 11/26/2022]
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24
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Costa LG, de Laat R, Tagliaferri S, Pellacani C. A mechanistic view of polybrominated diphenyl ether (PBDE) developmental neurotoxicity. Toxicol Lett 2014; 230:282-94. [PMID: 24270005 PMCID: PMC4028440 DOI: 10.1016/j.toxlet.2013.11.011] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/12/2013] [Indexed: 01/01/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs), extensively used in the past few decades as flame retardants in a variety of consumer products, have become world-wide persistent environmental pollutants. Levels in North America are usually higher than those in Europe and Asia, and body burden is 3-to-9-fold higher in infants and toddlers than in adults. The latter has raised concern for potential developmental toxicity and neurotoxicity of PBDEs. Experimental studies in animals and epidemiological observations in humans suggest that PBDEs may be developmental neurotoxicants. Pre- and/or post-natal exposure to PBDEs may cause long-lasting behavioral abnormalities, particularly in the domains of motor activity and cognition. The mechanisms underlying the developmental neurotoxic effects of PBDEs are not known, though several hypotheses have been put forward. One general mode of action relates to the ability of PBDEs to impair thyroid hormone homeostasis, thus indirectly affecting the developing brain. An alternative or additional mode of action involves a direct effect of PBDEs on nervous system cells; PBDEs can cause oxidative stress-related damage (DNA damage, mitochondrial dysfunction, apoptosis), and interfere with signal transduction (particularly calcium signaling), and with neurotransmitter systems. Important issues such as bioavailability and metabolism of PBDEs, extrapolation of results to low level of exposures, and the potential effects of interactions among PBDE congeners and between PBDEs and other contaminants also need to be taken into account.
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Affiliation(s)
- Lucio G Costa
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; Department of Neuroscience, University of Parma, Parma, Italy.
| | - Rian de Laat
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
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25
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Cary TL, Ortiz-Santaliestra ME, Karasov WH. Immunomodulation in post-metamorphic northern leopard frogs, Lithobates pipiens, following larval exposure to polybrominated diphenyl ether. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:5910-5919. [PMID: 24735054 DOI: 10.1021/es405776m] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Pollutants and disease are factors implicated in amphibian population declines, and it is hypothesized that these factors exert a synergistic adverse effect, which is mediated by pollutant-induced immunosuppression. Polybrominated diphenyl ethers (PBDEs) are ubiquitous pollutants that can exert immunotoxicity, making them of interest to test effects on amphibian immune function. We orally exposed Lithobates (Rana) pipiens tadpoles to environmentally realistic levels (0-634 ng/g wet diet) of a pentabromodiphenyl ether mixture (DE-71) from as soon as they became free-swimming through metamorphic climax. To assess adaptive immune response in juvenile frogs, we used an enzyme-linked immunosorbent assay to measure specific IgY production following immunization with keyhole limpet hemocyanin (KLH). Specific KLH antibody response was significantly decreased in juvenile frogs that had been exposed to PBDEs as tadpoles. When assessing innate immune responses, we found significantly different neutrophil counts among treatments; however, phagocytic activity of neutrophils was not significantly different. Secretion of antimicrobial skin peptides (AMPs) nonsignificantly decreased with increasing PBDE concentrations, and no significant effect of PBDE treatment was observed on efficacy of AMPs to inhibit chytrid fungus (Batrachochytrium dendrobatidis) growth. Our findings demonstrate that environmentally realistic concentrations of PBDEs are able to alter immune function in frogs; however, further research is needed to determine how these alterations impact disease susceptibility in L. pipiens.
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Affiliation(s)
- Tawnya L Cary
- Department of Zoology and ‡Department of Forest & Wildlife Ecology, University of Wisconsin , Madison, Wisconsin 53706, United States
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26
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A rapid throughput approach identifies cognitive deficits in adult zebrafish from developmental exposure to polybrominated flame retardants. Neurotoxicology 2014; 43:134-142. [PMID: 24674958 DOI: 10.1016/j.neuro.2014.03.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 03/13/2014] [Accepted: 03/13/2014] [Indexed: 12/18/2022]
Abstract
A substantial body of evidence has correlated the human body burdens of some polybrominated diphenyl ether (PBDE) flame retardants with cognitive and other behavioral deficits. Adult zebrafish exhibit testable learning and memory, making them an increasingly attractive model for neurotoxicology. Our goal was to develop a rapid throughput means of identifying the cognitive impact of developmental exposure to flame retardants in the zebrafish model. We exposed embryos from 6h post fertilization to 5 days post fertilization to either PBDE 47 (0.1μM), PBDE 99 (0.1μM) or PBDE 153 (0.1μM), vehicle (0.1% DMSO), or embryo medium (EM). The larvae were grown to adulthood and evaluated for the rate at which they learned an active-avoidance response in an automated shuttle box array. Zebrafish developmentally exposed to PBDE 47 learned the active avoidance paradigm significantly faster than the 0.1% DMSO control fish (P<0.0001), but exhibited significantly poorer performance when retested suggestive of impaired memory retention or altered neuromotor activity. Learning in the PBDE 153 group was not significantly different from the DMSO group. Developmental exposure to 0.1% DMSO impaired adult active avoidance learning relative to the sham group (n=39; P<0.0001). PBDE 99 prevented the DMSO effect, yielding a learning rate not significantly different from the sham group (n=36; P>0.9). Our results underscore the importance of vehicle choice in accurately assessing chemical effects on behavior. Active avoidance response in zebrafish is an effective model of learning that, combined with automated shuttle box testing, will provide a highly efficient platform for evaluating persistent neurotoxic hazard from many chemicals.
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27
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Alterations to the circuitry of the frontal cortex following exposure to the polybrominated diphenyl ether mixture, DE-71. Toxicology 2013; 312:48-55. [PMID: 23916505 DOI: 10.1016/j.tox.2013.07.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/19/2013] [Accepted: 07/23/2013] [Indexed: 11/21/2022]
Abstract
Recent studies have identified exposure to polybrominated diphenyl ethers (PBDEs) as a risk factor for deficits in cognitive functioning seen in children as well as adults. Additionally, similar alterations in learning and memory have also been observed in animal models of PBDE exposure. However, given these findings, the molecular alterations that may underlie these neurobehavioral endpoints have not been identified. As the frontal cortex is involved in modulating several cognitive functions, the purpose of our study was to investigate the possible changes to the GABAergic and glutamatergic neurotransmitter systems located in the frontal cortex following exposure to the PBDE mixture, DE-71. Primary cultured neurons isolated from the frontal cortex showed a dose-dependent reduction in neurons as well as neurite outgrowth. Furthermore, evaluation of DE-71 neurotoxicity in the frontal cortex using an in vivo model showed alterations to specific proteins involved in mediating GABA and glutamate neurotransmission, including GAD67, vGAT, vGlut, and GABA(A) 2α receptor subunit. Interestingly, these alterations appeared to be preferential for the GABA and glutamate systems located in the frontal cortex. These findings identify specific targets of PBDE neurotoxicity and provide a possible molecular mechanism for PBDE-mediated neurobehavioral deficits that arise from the frontal cortex.
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28
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Li T, Wang W, Pan YW, Xu L, Xia Z. A hydroxylated metabolite of flame-retardant PBDE-47 decreases the survival, proliferation, and neuronal differentiation of primary cultured adult neural stem cells and interferes with signaling of ERK5 MAP kinase and neurotrophin 3. Toxicol Sci 2013; 134:111-24. [PMID: 23564643 DOI: 10.1093/toxsci/kft083] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Polybrominated diphenyl ethers (PBDEs) are a group of organobromine compounds widely used as flame retardants. PBDE-47 is one of the most prominent PBDE congeners found in human tissues, and it can be transformed into several metabolites, including 6-OH-PBDE-47. Recent studies have shown that PBDE-47 is neurotoxic to animals and possibly humans. However, the basis for the neurotoxicity of PBDEs and their metabolites is unclear. For example, it is not known whether PBDEs affect adult neurogenesis, a process implicated in learning and memory and in olfactory behavior. In this study, we examined the toxicity of PBDEs for primary adult neural stem/progenitor cells (aNSCs) isolated from the subventricular zone (SVZ) of adult mice. We discovered that 6-OH-PBDE-47, but not its parent compound PBDE-47, is cytotoxic for aNCSs using MTS metabolism and cell number as a measure of cytotoxicity. Interestingly, 6-OH-PBDE-47 induced apoptosis at concentrations above 7.5μM inhibited proliferation at 2.5-5μM while suppressing neuronal and oligodendrocyte differentiation at submicromolar concentrations (≤ 1μM). The effect on proliferation was reversed upon removal of 6-OH-PBDE-47 and correlated with selective but reversible inhibition of ERK5 activation by mitogenic growth factors EGF and bFGF. 6-OH-PBDE-47 also inhibited the proneuronal differentiation effect of neurotrophin 3 (NT3) and NT3 activation of ERK5. Together, these data show that 6-OH-PBDE-47 is more toxic than its parent compound for SVZ-derived aNSCs and that it inhibits multiple aspects of adult neurogenesis. Furthermore, inhibition of ERK5 signaling may underlie the adverse effect of 6-OH-PBDE-47 on proliferation and neuronal differentiation. Our data suggest that exposure to PBDE-based flame retardants could cause neurotoxicity in the adult brain by interfering with adult neurogenesis.
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Affiliation(s)
- Tan Li
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
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