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Ma G, Ma K, Zhang J, Zhao X, Wang Q, Chen Y, Lu J, Wei X, Wang X, Yu H. Mechanistic insight into biotransformation of novel triazine-based flame retardant 1,3,5-tris(2,3-dibromopropyl)-1,3,5-triazinane-2,4,6-trione by human cytochrome P450s. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 348:123883. [PMID: 38548154 DOI: 10.1016/j.envpol.2024.123883] [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: 02/01/2024] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/21/2024]
Abstract
The escalating focus on the environmental occurrence and toxicology of emerging pollutants underscores the imperative need for a profound exploration of their metabolic transformations mediated by human CYP450 enzymes. Such investigations have the potential to unravel the intricate metabolite profiles, substantially altering the toxicological outcomes. In this study, we integrated the computational simulations with in vitro metabolism experiments to investigate the metabolic activity and mechanism of an emerging pollutant, 1,3,5-tris(2,3-dibromopropyl)-1,3,5-triazinane-2,4,6-trione (TDBP-TAZTO), catalyzed by human CYP450s. The results highlight the important contributions of CYP2E1, 3A4 and 2C9 to the biotransformation of TDBP-TAZTO, leading to the identification of four distinct metabolites. The effective binding conformations governing biotransformation reactions of TDBP-TAZTO within active CYP450s are unveiled. Structural instability of primary hydroxyTDBP-TAZTO products suggests three potential outcomes: (1) generation of an alcohol metabolite through successive debromination and reduction reactions, (2) formation of a dihydroxylated metabolite through secondary hydroxylation by CYP450, and (3) production of an N-dealkylated metabolite via decomposition and isomerization reactions in the aqueous environment. The formation of a desaturated debrominated metabolite may arise from H-abstraction and barrier-free Br release during the primary oxidation, potentially competing with the generation of hydroxyTDBP-TAZTO. These findings provide detailed mechanistic insight into TDBP-TAZTO biotransformation by CYP450s, which can enrich our understanding of the metabolic fate and associated health risk of this chemical.
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Affiliation(s)
- Guangcai Ma
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004, Jinhua, China
| | - Kan Ma
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004, Jinhua, China
| | - Jing Zhang
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004, Jinhua, China
| | - Xianglong Zhao
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004, Jinhua, China
| | - Qiuyi Wang
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004, Jinhua, China
| | - Yewen Chen
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004, Jinhua, China
| | - Jiayu Lu
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004, Jinhua, China
| | - Xiaoxuan Wei
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004, Jinhua, China
| | - Xueyu Wang
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004, Jinhua, China
| | - Haiying Yu
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004, Jinhua, China; Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Shuren Street 8, 310015, Hangzhou, China.
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Lan Y, Gao X, Xu H, Li M. 20 years of polybrominated diphenyl ethers on toxicity assessments. WATER RESEARCH 2024; 249:121007. [PMID: 38096726 DOI: 10.1016/j.watres.2023.121007] [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: 09/17/2023] [Revised: 11/17/2023] [Accepted: 12/09/2023] [Indexed: 01/03/2024]
Abstract
Polybrominated diphenyl ethers (PBDEs) serve as brominated flame retardants which continue to receive considerable attention because of their persistence, bioaccumulation, and potential toxicity. Although PBDEs have been restricted and phased out, large amounts of commercial products containing PBDEs are still in use and discarded annually. Consequently, PBDEs added to products can be released into our surrounding environments, particularly in aquatic systems, thus posing great risks to human health. Many studies and reviews have described the possible toxic effects of PBDEs, while few studies have comprehensively summarized and analyzed the global trends of their toxicity assessment. Therefore, this study utilizes bibliometrics to evaluate the worldwide scientific output of PBDE toxicity and analyze the hotspots and future trends of this field. Firstly, the basic information including the most contributing countries/institutions, journals, co-citations, influential authors, and keywords involved in PBDE toxicity assessment will be visualized. Subsequently, the potential toxicity of PBDE exposure to diverse systems, such as endocrine, reproductive, neural, and gastrointestinal tract systems, and related toxic mechanisms will be discussed. Finally, we conclude this review by outlining the current challenges and future perspectives in environmentally relevant PBDE exposure, potential carriers for PBDE transport, the fate of PBDEs in the environment and human bodies, advanced stem cell-derived organoid models for toxicity assessment, and promising omics technologies for obtaining toxic mechanisms. This review is expected to offer systematical insights into PBDE toxicity assessments and facilitate the development of PBDE-based research.
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Affiliation(s)
- Yingying Lan
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China; State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Xue Gao
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400030, China
| | - Haiwei Xu
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China.
| | - Minghui Li
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China; Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400030, China.
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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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Wu M, Yan F, Liu Q, Liao G, Shen Y, Bai Z, Liu X. Effects of Xenobiotic Compounds on Preeclampsia and Potential Mechanisms. TOXICS 2023; 11:492. [PMID: 37368592 DOI: 10.3390/toxics11060492] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/09/2023] [Accepted: 05/10/2023] [Indexed: 06/29/2023]
Abstract
Preeclampsia (PE) refers to a disease with new hypertension and albuminuria or other end-organ damage after 20 weeks of pregnancy. As a major complication of pregnancy, PE can increase the morbidity and mortality of pregnant women and fetuses and cause serious social burden. Recently, it has been found that exposure to xenobiotic compounds, especially endocrine disruptors in the environment, may contribute to the development of PE. However, the underlying mechanism is still unclear. It is generally believed that PE is related to placental dysplasia, spiral artery remodelling failure, oxidative stress, etc. Therefore, in order to better prevent the occurrence of PE and reduce the damage and impact on mother and fetus, this paper reviews the role and potential mechanism of PE induced by exogenous chemicals and provides an outlook on the environmental etiology of PE.
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Affiliation(s)
- Miaoliang Wu
- The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
- School of Public Health, Dongguan Key Laboratory of Environmental Medicine, Guangdong Medical University, Dongguan 523808, China
| | - Fuhui Yan
- The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
- School of Public Health, Dongguan Key Laboratory of Environmental Medicine, Guangdong Medical University, Dongguan 523808, China
| | - Qian Liu
- School of Public Health, Dongguan Key Laboratory of Environmental Medicine, Guangdong Medical University, Dongguan 523808, China
| | - Ganzhong Liao
- School of Public Health, Dongguan Key Laboratory of Environmental Medicine, Guangdong Medical University, Dongguan 523808, China
| | - Yilin Shen
- School of Public Health, Dongguan Key Laboratory of Environmental Medicine, Guangdong Medical University, Dongguan 523808, China
| | - Zhi Bai
- The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
| | - Xiaoshan Liu
- The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
- School of Public Health, Dongguan Key Laboratory of Environmental Medicine, Guangdong Medical University, Dongguan 523808, China
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Charles D, Berg V, Nøst TH, Wilsgaard T, Bergdahl IA, Huber S, Ayotte P, Averina M, Sandanger T, Rylander C. Polybrominated diphenyl ethers in type 2 diabetes mellitus cases and controls: Repeated measurements prior to and after diagnosis. Int J Hyg Environ Health 2023; 249:114148. [PMID: 36881976 DOI: 10.1016/j.ijheh.2023.114148] [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: 11/11/2022] [Revised: 02/24/2023] [Accepted: 02/27/2023] [Indexed: 03/07/2023]
Abstract
BACKGROUND Previous studies have reported associations between certain persistent organic pollutants (POPs) and type 2 diabetes mellitus (T2DM). Polybrominated diphenyl ethers (PBDEs) are a class of POPs that are found in increasing concentrations in humans. Although obesity is a known risk factor for T2DM and PBDEs are fat-soluble, very few studies have investigated associations between PBDEs and T2DM. No longitudinal studies have assessed associations between repeated measurements of PBDE and T2DM in the same individuals and compared time trends of PBDEs in T2DM cases and controls. OBJECTIVES To investigate associations between pre- and post-diagnostic measurements of PBDEs and T2DM and to compare time trends of PBDEs in T2DM cases and controls. METHODS Questionnaire data and serum samples from participants in the Tromsø Study were used to conduct a longitudinal nested case-control study among 116 T2DM cases and 139 controls. All included study participants had three pre-diagnostic blood samples (collected before T2DM diagnosis in cases), and up to two post-diagnostic samples after T2DM diagnosis. We used logistic regression models to investigate pre- and post-diagnostic associations between PBDEs and T2DM, and linear mixed-effect models to assess time trends of PBDEs in T2DM cases and controls. RESULTS We observed no substantial pre- or post-diagnostic associations between any of the PBDEs and T2DM, except for BDE-154 at one of the post-diagnostic time-points (OR = 1.65, 95% CI: 1.00, 2.71). The overall time trends of PBDE concentrations were similar for cases and controls. DISCUSSION The study did not support PBDEs increasing the odds of T2DM, prior to or after T2DM diagnosis. T2DM status did not influence the time trends of PBDE concentrations.
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Affiliation(s)
- Dolley Charles
- Department of Community Medicine, Faculty of Health Sciences, UiT, The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Vivian Berg
- Department of Medical Biology, Faculty of Health Sciences, UiT, The Arctic University of Norway, NO-9037, Tromsø, Norway; Department of Laboratory Medicine, Division of Diagnostic Services, University Hospital of North Norway, NO-9038, Tromsø, Norway
| | - Therese Haugdahl Nøst
- Department of Community Medicine, Faculty of Health Sciences, UiT, The Arctic University of Norway, NO-9037, Tromsø, Norway; Department of Community Medicine and Nursing, Norwegian University of Science and Technology, NO-7491, Trondheim, Norway
| | - Tom Wilsgaard
- Department of Community Medicine, Faculty of Health Sciences, UiT, The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Ingvar A Bergdahl
- Department of Public Health and Clinical Medicine, Section of Sustainable Health, Umeå University, Umeå, Sweden
| | - Sandra Huber
- Department of Laboratory Medicine, Division of Diagnostic Services, University Hospital of North Norway, NO-9038, Tromsø, Norway
| | - Pierre Ayotte
- Department of Social and Preventive Medicine, Laval University, Québec, QC, Canada; Centre de Toxicologie du Québec, INSPQ, Québec, QC, Canada
| | - Maria Averina
- Department of Laboratory Medicine, Division of Diagnostic Services, University Hospital of North Norway, NO-9038, Tromsø, Norway; Department of Clinical Medicine, Faculty of Health Sciences, UiT, The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Torkjel Sandanger
- Department of Community Medicine, Faculty of Health Sciences, UiT, The Arctic University of Norway, NO-9037, Tromsø, Norway; NILU-Norwegian Institute for Air Research, NO-9007, Tromsø, Norway
| | - Charlotta Rylander
- Department of Community Medicine, Faculty of Health Sciences, UiT, The Arctic University of Norway, NO-9037, Tromsø, Norway.
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Liu L, Cui H, Huang Y, Yan H, Zhou Y, Wan Y. Molecular docking and in vitro evaluations reveal the role of human cytochrome P450 3A4 in the cross-coupling metabolism of phenolic xenobiotics. ENVIRONMENTAL RESEARCH 2023; 220:115256. [PMID: 36634892 DOI: 10.1016/j.envres.2023.115256] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/11/2022] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Abstract
Metabolism generally transforms xenobiotics into more polar and hydrophilic products, facilitating their elimination from the body. Recently, a new metabolic pathway that transforms phenolic xenobiotics into more lipophilic and bioactive dimer products was discovered. To elucidate the role of cytochrome P450 (CYP) enzymes in mediating this cross-coupling metabolism, we used high-throughput screening to identify the metabolites generated from the coupling of 20 xenobiotics with four endogenous metabolites in liver microsomes. Endogenous vitamin E (VE) was the most reactive metabolite, as VE reacted with seven phenolic xenobiotics containing various structures (e.g., an imidazoline ring or a diphenol group) to generate novel lipophilic ethers such as bakuchiol-O-VE, phentolamine-O-VE, phenylethyl resorcinol-O-VE, 2-propanol-O-VE, and resveratrol-O-VE. Seven recombinant CYP enzymes were successfully expressed and purified in Escherichia coli. Integration of the results of recombinant human CYP incubation and molecular docking identified the central role of CYP3A4 in the cross-coupling metabolic pathway. Structural analysis revealed the π-π interactions, hydrogen bonds, and hydrophobic interactions between reactive xenobiotics and VE in the malleable active sites of CYP3A4. The consistency between the molecular docking results and the in vitro human cytochrome P450 evaluation shows that docking calculations can be used to screen molecules participating in cross-coupling metabolism. The results of this study provide supporting evidence for the overlooked toxicological effects induced by direct reactions between xenobiotics and endogenous metabolites during metabolic processes.
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Affiliation(s)
- Liu Liu
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Hongyang Cui
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yixuan Huang
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Hao Yan
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yulan Zhou
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yi Wan
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
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Khan AUH, Naidu R, Dharmarajan R, Fang C, Shon H, Dong Z, Liu Y. The interaction mechanisms of co-existing polybrominated diphenyl ethers and engineered nanoparticles in environmental waters: A critical review. J Environ Sci (China) 2023; 124:227-252. [PMID: 36182134 DOI: 10.1016/j.jes.2021.10.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/13/2021] [Accepted: 10/13/2021] [Indexed: 06/16/2023]
Abstract
This review focuses on the occurrence and interactions of engineered nanoparticles (ENPs) and brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) in water systems and the generation of highly complex compounds in the environment. The release of ENPs and BFRs (e.g. PBDEs) to aquatic environments during their usage and disposal are summarised together with their key interaction mechanisms. The major interaction mechanisms including electrostatic, van der Waals, hydrophobic, molecular bridging and steric, hydrogen and π-bonding, cation bridging and ligand exchange were identified. The presence of ENPs could influence the fate and behaviour of PBDEs through the interactions as well as induced reactions under certain conditions which increases the formation of complex compounds. The interaction leads to alteration of behaviour for PBDEs and their toxic effects to ecological receptors. The intermingled compound (ENPs-BFRs) would show different behaviour from the parental ENPs or BFRs, which are currently lack of investigation. This review provided insights on the interactions of ENPs and BFRs in artificial, environmental water systems and wastewater treatment plants (WWTPs), which are important for a comprehensive risk assessment.
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Affiliation(s)
- Anwar Ul Haq Khan
- Global Centre for Environmental Remediation (GCER), College of Engineering Science and Environment, The University of Newcastle, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ATC Building, The University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Ravi Naidu
- Global Centre for Environmental Remediation (GCER), College of Engineering Science and Environment, The University of Newcastle, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ATC Building, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Raja Dharmarajan
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ATC Building, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Cheng Fang
- Global Centre for Environmental Remediation (GCER), College of Engineering Science and Environment, The University of Newcastle, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ATC Building, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Hokyong Shon
- School of Civil and Environmental Engineering, University of Technology Sydney (UTS), City Campus, Broadway, NSW 2007, Australia
| | - Zhaomin Dong
- School of Space and Environment, Beihang University, Beijging 100191, China
| | - Yanju Liu
- Global Centre for Environmental Remediation (GCER), College of Engineering Science and Environment, The University of Newcastle, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ATC Building, The University of Newcastle, Callaghan, NSW 2308, Australia.
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Metcalfe CD, Bayen S, Desrosiers M, Muñoz G, Sauvé S, Yargeau V. An introduction to the sources, fate, occurrence and effects of endocrine disrupting chemicals released into the environment. ENVIRONMENTAL RESEARCH 2022; 207:112658. [PMID: 34990614 DOI: 10.1016/j.envres.2021.112658] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 12/29/2021] [Accepted: 12/30/2021] [Indexed: 06/14/2023]
Abstract
Many classes of compounds are known or suspected to disrupt the endocrine system of vertebrate and invertebrate organisms. This review of the sources and fate of selected endocrine disrupting chemicals (EDCs) in the environment includes classes of compounds that are "legacy" contaminants, as well as contaminants of emerging concern. EDCs included for discussion are organochlorine compounds, halogenated aromatic hydrocarbons, brominated flame retardants, per- and polyfluoroalkyl substances, alkylphenols, phthalates, bisphenol A and analogues, pharmaceuticals, drugs of abuse and steroid hormones, personal care products, and organotins. An exhaustive survey of the fate of these contaminants in all environmental media (e.g., air, water, soil, biota, foods and beverages) is beyond the scope of this review, so the priority is to highlight the fate of EDCs in environmental media for which there is a clear link between exposure and endocrine effects in humans or in biota from other taxa. Where appropriate, linkages are also made between the fate of EDCs and regulatory limits such as environmental quality guidelines for water and sediments and total daily intake values for humans.
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Affiliation(s)
| | - S Bayen
- McGill University, Montréal, QC, Canada
| | - M Desrosiers
- Ministère du Développement durable, de l'Environnement et de la Lutte contre les changements climatiques du Québec. Québec City, QC, Canada
| | - G Muñoz
- Université de Montréal, Montréal, QC, Canada
| | - S Sauvé
- Université de Montréal, Montréal, QC, Canada
| | - V Yargeau
- McGill University, Montréal, QC, Canada
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Liu L, Cui H, Huang Y, Zhou Y, Hu J, Wan Y. Enzyme-Mediated Reactions of Phenolic Pollutants and Endogenous Metabolites as an Overlooked Metabolic Disruption Pathway. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:3634-3644. [PMID: 35238542 DOI: 10.1021/acs.est.1c08141] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
It is generally recognized that phenol-containing molecules mainly undergo phase II metabolic reactions, whereas glucuronide and sulfate are conjugated to form water-soluble products. Here, we report direct reactions of phenolic pollutants (triclosan, alkylphenol, bisphenol A [BPA], and its analogues) and some endogenous metabolites (vitamin E [VE] and estradiol) to generate new lipophilic ether products (e.g., BPA-O-VEs and alkylphenol-O-estradiol). A nontargeted screening strategy was used to identify the products in human liver microsome incubations, and the most abundant products (BPA-O-VEs) were confirmed via in vivo exposure in mice. BPA-O-VEs were frequently detected in sera from the general population at levels comparable to those of glucuronide/sulfate-conjugated BPA. Recombinant human cytochrome P450s were applied to find that CYP3A4 catalyzed the formation of these newly discovered ether metabolites by linking the VE hydroxyl group to the BPA phenolic ring, leading to the significantly reduced antioxidative activities of BPA-O-VEs compared to VEs. The effects of the reaction on the homeostasis of reacted biomolecules were finally assessed by in vitro assay and in vivo mice exposures. The generation of BPA-O-VEs decreased the VE concentrations and increased the reactive oxygen species generation after exposure to BPA at environmentally relevant concentrations. The identified reactions provided an overlooked metabolic disruption pathway for phenolic pollutants.
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Affiliation(s)
- Liu Liu
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Hongyang Cui
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yixuan Huang
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yulan Zhou
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Jianying Hu
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yi Wan
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
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10
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Song M, Wang Y, Chen Z, Gao H, Yang Z, Yu H, Liu Y. Human CYP enzyme-activated genotoxicity of 2,2',4,4'-tetrabromobiphenyl ether in mammalian cells. CHEMOSPHERE 2022; 291:132784. [PMID: 34742755 DOI: 10.1016/j.chemosphere.2021.132784] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 06/13/2023]
Abstract
Polybrominated biphenyl ethers (PBDEs) are a group of persistent organic pollutants with endocrine-disrupting, neurotoxic, tumorigenic and DNA-damaging activities. They are hydroxylated by human liver microsomal CYP enzymes, however, their mutagenicity remains unknown. In this study, 2,2',4,4'-tetrabromobiphenyl ether (BDE-47, relatively abundant in human tissues) was investigated for micronuclei induction and DNA damage in mammalian cells. The results indicated that BDE-47 up to 80 μM under a 6 h/18 h (exposure/recovery, covering 2 cell cycles) regime did not induce micronuclei in V79-Mz and V79-derived cell lines expressing human CYP1A1 or 1A2, while it was moderately positive in human CYP2B6-, 2E1-and 3A4-expressing cell lines (V79-hCYP2B6, V79-hCYP2E1-hSULT1A1 and V79-hCYP3A4-hOR, respectively). Following 24 h exposure, BDE-47 induced micronuclei in V79-hCYP2E1-hSULT1A1 and V79-hCYP3A4 cells at increased potencies. In the human hepatoma (HepG2) cells BDE-47 (48 h exposure) was inactive up to 40 μM, however, pretreatment of the cells with ethanol (0.2%, v:v, inducer of CYP2E1) or rifampicin (10 μM, inducer of CYP3A4) led to significant micronuclei formation by BDE-47; pretreatment with bisphenol AF (100 nM) also potentiated BDE-47-induced micronuclei formation (which was blocked by a CYP2E1 inhibitor trans-1,2-dichloroethylene or a CYP3A inhibitor (ketoconazole). Immunofluorescent staining of centromere protein B with the micronuclei formed by BDE-47 in HepG2 cells pretreated with ethanol or rifampicin demonstrated selective formation of centromere-containing micronuclei. The increased phosphorylation of both histones H2AX and H3 in HepG2 by BDE-47 also indicated an aneugenic potential. Therefore, this study suggests that BDE-47 is an aneugen activated by several human CYP enzymes.
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Affiliation(s)
- Meiqi Song
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Yujian Wang
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Zhihong Chen
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Hongbin Gao
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China; Guangdong Laboratory Animals Monitoring Institute, Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, 510663, China
| | - Zongying Yang
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Hang Yu
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Yungang Liu
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China.
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Li T, Sun Y, Zeng Y, Sanganyado E, Liang B, Liu W. 6-OH-BDE-47 inhibited proliferation of skin fibroblasts from pygmy killer whale by inducing cell cycle arrest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 807:150561. [PMID: 34624692 DOI: 10.1016/j.scitotenv.2021.150561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 08/16/2021] [Accepted: 09/20/2021] [Indexed: 06/13/2023]
Abstract
Hydroxylated polybrominated diphenyl ethers (OH-BDEs) are major transformation products of PBDEs that readily bioaccumulate in the marine food web. Although 6-OH-BDE-47 is frequently and abundantly detected in cetaceans, its potential toxic effects are largely unknown. We explored the toxicological pathways and mechanisms of OH-BDEs by exposing pygmy killer whale skin fibroblast cell lines (PKW-LWHT) to 6-OH-BDE-47 at concentrations ranging from 0.02, 0.2, 2 to 4 μM. The result showed that 6-OH-BDE-47 inhibited cell proliferation in a concentration- and time-dependent manner. The cell cycle data revealed that the cell cycle was arrest at the G0/G1 phase by 6-OH-BDE-47. Using qPCR and Western blot assay, we found that 6-OH-BDE-47 up-regulated the transcription and expression level of p21 and RB1 and down-regulated the expression level of Proliferating Cell Nuclear Antigen (PCNA), CDK2, CDK4, cyclin D1, cyclin E2, E2F1, and E2F3 and the cellular phosphorylated RB1. The results showed that 6-OH-BDE-47 was able to arrest the cell cycle of PKW-LWHT cells at G1 phase by changing the expression level of related regulatory genes in G1 stage, and finally inhibit cell proliferation.
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Affiliation(s)
- Tong Li
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Science, Shantou University, Shantou, Guangdong 515063, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China
| | - Yajing Sun
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Science, Shantou University, Shantou, Guangdong 515063, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China
| | - Ying Zeng
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Science, Shantou University, Shantou, Guangdong 515063, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China
| | - Edmond Sanganyado
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Science, Shantou University, Shantou, Guangdong 515063, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China
| | - Bo Liang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Science, Shantou University, Shantou, Guangdong 515063, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China.
| | - Wenhua Liu
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Science, Shantou University, Shantou, Guangdong 515063, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China.
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12
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Tang J, Hu B, Zheng H, Qian X, Zhang Y, Zhu J, Xu G, Chen D, Jin X, Li W, Xu L. 2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) activates Aryl hydrocarbon receptor (AhR) mediated ROS and NLRP3 inflammasome/p38 MAPK pathway inducing necrosis in cochlear hair cells. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 221:112423. [PMID: 34146985 DOI: 10.1016/j.ecoenv.2021.112423] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/08/2021] [Accepted: 06/11/2021] [Indexed: 05/27/2023]
Abstract
Tetrabromodiphenyl ether (BDE-47) is widely used as commercial flame retardants that can be released into the environment and finally enter human body through the food chain. It has been identified to generate neurotoxicity, but little is known about auditory damage and the underlying mechanism following BDE-47 exposure. This study aimed to assess the cell viability with BDE-47 concentration ranging from 0 to 150 μM in mouse organ of Corti-derived cell lines (HEI-OC1). Aryl hydrocarbon receptor (AhR) as an environmental sensor, reactive oxygen species (ROS), NLRP3 inflammasome and p38 MAPK pathways were detected. Results: (1) BDE-47 inhibited the viability in a time- and dose-dependent way in HEI-OC1 cells. Cell cycle was arrested in G1 phase by BDE-47; (2) Elevated intracellular ROS, LDH levels and necrosis were found, which was alleviated by pretreatment with ROS scavenger N-acetylcysteine (NAC); (3) AhR plays an essential role in ligand-regulated transcription factor activation by exogenous environmental compounds. We found increased expression of AhR and decreased downstream targets of CYP 1A1 and CYP 1B1 in BDE-47-treated HEI-OC1 cells, which was reversed by the AhR antagonist CH-223191 for 2 h before BDE-47 exposure. No significant change was detected in CYP 2B; (4) Enhanced expressions of NLRP3 and caspase-1 were induced by BDE-47, with up-regulations of both pro-inflammatory factors for IL-1β, IL-6 and TNF-α, and anti-inflammatory factors for IL-4, IL-10 and IL-13, but down-regulation for IL-1α; (5) Additionally, the p38 MAPK signaling pathway was activated with increased phosphorylation levels of MKK/3/6, p38 MAPK and NF-kB. Overall, our findings illustrate a role of AhR in ROS-induced necrosis of cochlear hair cells by BDE-47 exposure, in which NLRP3 inflammasome and p38 MAPK signaling pathways are activated. The current study first elucidates the sense of hearing damage induced by BDE-47, and cell-specific or mixture exposures in vivo or human studies are needed to confirm this association.
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Affiliation(s)
- Jie Tang
- Department of Pathology, The Key-Innovative Discipline of Molecular Diagnostics, Jiaxing Hospital of Traditional Chinese Medicine, Jiaxing University, Jiaxing 314001, ZJ, China
| | - Bo Hu
- Department of Pathology, The Key-Innovative Discipline of Molecular Diagnostics, Jiaxing Hospital of Traditional Chinese Medicine, Jiaxing University, Jiaxing 314001, ZJ, China
| | - Huaping Zheng
- Department of Otolaryngology, Jiaxing Hospital of Traditional Chinese Medicine, Jiaxing University, Jiaxing 314001, ZJ, China
| | - Xiaolan Qian
- Department of Pathology, The Key-Innovative Discipline of Molecular Diagnostics, Jiaxing Hospital of Traditional Chinese Medicine, Jiaxing University, Jiaxing 314001, ZJ, China
| | - Yi Zhang
- Department of Pathology, The Key-Innovative Discipline of Molecular Diagnostics, Jiaxing Hospital of Traditional Chinese Medicine, Jiaxing University, Jiaxing 314001, ZJ, China
| | - Jia Zhu
- Department of Immunopathology, Jiaxing University Medical College, Jiaxing 314001, ZJ, China
| | - Guangtao Xu
- Forensic and Pathology Laboratory, Jiaxing University Medical College, Jiaxing 314001, ZJ, China
| | - Deqing Chen
- Forensic and Pathology Laboratory, Jiaxing University Medical College, Jiaxing 314001, ZJ, China
| | - Xin Jin
- Forensic and Pathology Laboratory, Jiaxing University Medical College, Jiaxing 314001, ZJ, China
| | - Wanlu Li
- Forensic and Pathology Laboratory, Jiaxing University Medical College, Jiaxing 314001, ZJ, China
| | - Long Xu
- Forensic and Pathology Laboratory, Jiaxing University Medical College, Jiaxing 314001, ZJ, China; Department of Public Health, Jiaxing University Medical College, Jiaxing 314001, ZJ, China.
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13
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Pietron WJ, Warenik-Bany M, Wozniak B. Polybrominated diphenyl ethers (PBDEs) in raw milk from different animal species and in infant formula. Occurrence and risk assessment. CHEMOSPHERE 2021; 278:130479. [PMID: 34126691 DOI: 10.1016/j.chemosphere.2021.130479] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 03/29/2021] [Accepted: 04/01/2021] [Indexed: 05/06/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) are widespread, persistent in the environment, and classified as global pollutants. Their presence has been confirmed in various types of food which adversely affect human health when consumed in sufficient amounts. Although milk has advantageous nutritional qualities and there are health benefits associated with its consumption, it could also contain toxic PBDEs. The aim of the study was the determination of the concentrations of ten congeners (BDE -28, -47, -49, -99, -100, -138, -153, -154, -183, and 209) in cow's, sheep's, and goat's milk obtained from Polish farms and their determination in infant formula. A total of 103 samples of raw milk and infant formula were tested using an accredited high-resolution gas chromatography-high-resolution mass spectrometry method. PBDEs were detected in all analyzed samples, the highest concentration being found in sheep's milk (11.9 ng g-1 fat), and cow's milk containing the least contamination. BDE-209 makes the predominant contribution to the sum of the ten congeners, constituting at least 38%. The profiles of PBDEs were dependent on the milk type and the differences between its varieties are discussed. The highest median concentration of the sum of ten PBDEs (0.473 ng g-1 fat) was determined in infant formula, which was identified as an important source of infants' exposure (5.48 ng kg-1 b.w. day-1 calculated based on P95 concentration). Milk is a source of PBDE in the diet; however, considered in isolation its consumption does not pose a risk to either adults' or children's health.
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Affiliation(s)
- Wojciech Jerzy Pietron
- Radiobiology Department, National Veterinary Research Institute (NVRI), 57 Partyzantow Avenue, 24-100, Pulawy, Poland.
| | - Malgorzata Warenik-Bany
- Radiobiology Department, National Veterinary Research Institute (NVRI), 57 Partyzantow Avenue, 24-100, Pulawy, Poland
| | - Barbara Wozniak
- Pharmacology and Toxicology Department, National Veterinary Research Institute (NVRI), 57 Partyzantow Avenue, 24-100, Pulawy, Poland
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14
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Li X, Zhao X, Yao Y, Guo M, Li S. New insights into crosstalk between apoptosis and necroptosis co-induced by chlorothalonil and imidacloprid in Ctenopharyngodon idellus kidney cells. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 780:146591. [PMID: 33770597 DOI: 10.1016/j.scitotenv.2021.146591] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 03/13/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
Overuse and co-exposure of pesticides have become a public health problem and threat seriously water health and environmental organisms and even humans. Chlorothalonil (CT) and imidacloprid (IMI) are high-selling pesticides worldwide, which can persist in the environment, and present a series of severely toxic effects on non-target animals. However, the effect of co-application on aquatic organisms is unknown. Based on the concept of the toxic unit (TU), toxic interaction of CT and IMI was evaluated and showed the additive and synergistic toxicity on Ctenopharyngodon idellus (grass carp) kidney cell line (CIK cells). Cell death analysis found an obvious increase of the apoptosis and necrosis rates exposed to CT and IMI, and aggravation when applied together. Moreover, CT and IMI co-exposure accelerated the inhibition of CYP450s/ROS/HIF-1α signal, the decline of energy metabolism, mitochondrial dynamics disorder, activation of Bcl2/Bax/Cyt C/Casp3/Casp9 pathway and RIP1/RIP3/MLKL pathway. Bioinformatics analysis showed autophagy, cell response, NOD-like receptor signaling pathway might be affected by co-exposure. In summary, the above results indicate that co-exposure to CT and IMI has synergistic toxicity and aggravates cell death via inhibition of the CYP450s/ROS/HIF-1α signal. These data provide new insights for evaluating the stacking interaction and revealing the toxicological effects of pesticide mixture.
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Affiliation(s)
- Xiaojing Li
- College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, PR China
| | - Xia Zhao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China
| | - Yujie Yao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China
| | - Mengyao Guo
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China.
| | - Shu Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China.
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15
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Wei J, Xiao X, Li K, Song Y, Huang SK, Cai Z, Liu Z. Derivatization strategy for semi-quantitative analysis of medium- and long-chain fatty acids using multiple reaction monitoring. Talanta 2021; 233:122464. [PMID: 34215101 DOI: 10.1016/j.talanta.2021.122464] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 04/14/2021] [Accepted: 04/23/2021] [Indexed: 11/24/2022]
Abstract
Medium- and long-chain fatty acids (MLFAs) are essential energy sources in cells and possess vital biological functions. Characteristics of MLFAs in biosamples contributes to the understanding of biological process and finding potential biomarkers for relevant diseases. However, there are obstacles of the MLFAs determination due to their poor ionization efficiency in mass spectrometry and structural similarity of the MLFAs. Herein, a derivatization strategy was applied by labeling with d0-N, N-dimethyl-6,7-dihydro-5H-pyrrolo [3,4-d] pyrimidine-2-amine (d0-DHPP) and detecting with ultra-high performance liquid chromatography combined with tandem mass spectrometry (UHPLC-MS/MS) in multiple reaction monitoring (MRM) mode. The parallel isotope labeled internal standards were generated by tagging d6-DHPP to MLFAs. The simple and rapid derivatization procedure and mild reaction conditions greatly reduced the potential of MLFA degradation during the processing procedure. With the methodology, the chromatographic performance was greatly improved, and the mass spectrum response was enhanced up to 1, 600 folds. Finally, the developed derivatization method was applied to serum samples to analyze the alteration of MLFAs induced by 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) exposure in breast cancer nude mice. The semi-quantitative results demonstrated that the BDE-47 exposure significantly influenced the MLFA metabolism in mice.
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Affiliation(s)
- Juntong Wei
- Department of Respirology & Allergy, Third Affiliated Hospital of Shenzhen University, Shenzhen, 518020, China; State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China; State Key Laboratory of Respiratory Disease for Allergy at Shenzhen University, Shenzhen Key Laboratory of Allergy & Immunology, Shenzhen University School of Medicine, Shenzhen, China
| | - Xiaojun Xiao
- State Key Laboratory of Respiratory Disease for Allergy at Shenzhen University, Shenzhen Key Laboratory of Allergy & Immunology, Shenzhen University School of Medicine, Shenzhen, China
| | - Kun Li
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China; State Key Laboratory of Cotton Biology, Key Laboratory of Plant Stress Biology, School of Life Science, Henan University, Henan Province, China
| | - Yuanyuan Song
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China
| | - Shau-Ku Huang
- State Key Laboratory of Respiratory Disease for Allergy at Shenzhen University, Shenzhen Key Laboratory of Allergy & Immunology, Shenzhen University School of Medicine, Shenzhen, China
| | - Zongwei Cai
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China.
| | - Zhigang Liu
- Department of Respirology & Allergy, Third Affiliated Hospital of Shenzhen University, Shenzhen, 518020, China; State Key Laboratory of Respiratory Disease for Allergy at Shenzhen University, Shenzhen Key Laboratory of Allergy & Immunology, Shenzhen University School of Medicine, Shenzhen, China.
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16
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Ingle ME, Mínguez-Alarcón L, Carignan CC, Stapleton HM, Williams PL, Ford JB, Moravek MB, Hauser R, Meeker JD. Exploring reproductive associations of serum polybrominated diphenyl ether and hydroxylated brominated diphenyl ether concentrations among women undergoing in vitro fertilization. Hum Reprod 2021; 35:1199-1210. [PMID: 32424407 DOI: 10.1093/humrep/deaa063] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/21/2020] [Indexed: 12/15/2022] Open
Abstract
STUDY QUESTION Are serum concentrations of polybrominated diphenyl ethers (PBDEs) and hydroxylated brominated diphenyl ethers (OH-BDEs) associated with IVF endpoints? SUMMARY ANSWER Positive associations were observed for BDE153 and several OH-BDEs with IVF endpoints. WHAT IS KNOWN ALREADY PBDEs have been voluntarily phased out of production in the USA and EU due to their persistence and toxicity to humans and ecosystems. PBDEs have been associated with implantation failure among women undergoing IVF, yet some animal studies suggest greater toxicity from their metabolites, OH-BDEs. STUDY DESIGN, SIZE, DURATION We evaluated a subset of 215 women (contributing 330 IVF cycles) enrolled between 2005 and 2016 in a longitudinal cohort based at Massachusetts General Hospital Fertility Center. PARTICIPANTS/MATERIALS, SETTING, METHODS The following PBDEs were quantified: 47, 99, 100, 153 and 154 and the following OH-BDEs: 3-OH-BDE47, 5-OH-BDE47, 6-OH-BDE47 and 4-OH-BDE49. Clinical endpoints of IVF treatments were abstracted from electronic medical records. Associations of log-transformed PBDEs and OH-BDEs with IVF outcomes were assessed using multivariable generalized mixed models and cluster weighted generalized estimating equation models adjusted for lipids, age, BMI, race, year of sample collection, IVF protocol and FSH levels. Outcomes were adjusted to represent a percent change in outcome with an increase equal to the magnitude of the difference between the 75th and 25th percentiles for each specific compound (interquartile range (IQR) increase). MAIN RESULTS AND THE ROLE OF CHANCE Detection frequencies were highest for congeners 47 and 153 (82% ≥ method detection limit (MDL)) and metabolites 3 and 5-OH-BDE47 and 4-OH-BDE49 (92% > MDL). PBDE and OH-BDE geometric mean concentrations declined by up to 80% between participants recruited in 2005 and those recruited in 2016. An IQR increase of BDE153 was associated with an increase in the probability of implantation (relative risk (RR) = 1.26, 95% CI: 1.16, 1.36), clinical pregnancy (RR = 1.32, 95% CI: 1.19, 1.46) and live birth (RR = 1.34; 95% CI: 1.15, 1.54). An IQR increase in 3 and 5-OH-BDE47 was associated with increased probabilities of implantation (RR = 1.52; 95% CI: 1.11, 2.09), clinical pregnancy (RR = 1.66; 95% CI: 1.17, 2.36), and live birth (RR = 1.61; 95% CI: 1.07, 2.40). When models were stratified by race (White (86%)/Other race (14%)), associations remained positive for White women, yet inverse associations were observed for Other race women. An IQR increase in BDE47 was associated with a 46% decreased probability of clinical pregnancy (95% CI: 0.31, 0.95) for Other race women. LIMITATIONS, REASONS FOR CAUTION Despite the long half-lives of PBDEs and OH-BDEs, exposure misclassification is possible for women who underwent multiple treatment cycles over several months or years. It is also possible another medium, such as follicular fluid would be optimal to characterize exposure. We also tested associations for multiple congeners and metabolites with multiple outcomes. WIDER IMPLICATIONS OF THE FINDINGS Detections of serum concentrations of PBDEs and OH-BDEs were highest in the early years of the study and suggests that the phase-out of these compounds has contributed to a decrease in exposure. The negative associations found for PBDEs and IVF outcomes among other race women suggests the potential for racial disparity. Potential racial disparities in PBDE exposure and exploration of alternative flame retardants with reproductive health outcomes should be the focus of future investigations. STUDY FUNDING/COMPETING INTEREST(S) Funding for this research was supported by the National Institutes of Environmental Health Sciences (NIEHS) [R01 ES009718, ES022955, ES000002 and 009718T32ES007069]. The authors have no conflicts of interest.
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Affiliation(s)
- Mary E Ingle
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Lidia Mínguez-Alarcón
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Courtney C Carignan
- Department of Food Science and Nutrition, Michigan State University, East Lansing, MI, USA.,Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
| | | | - Paige L Williams
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA.,Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Jennifer B Ford
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Molly B Moravek
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Russ Hauser
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.,Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, University of Michigan, Ann Arbor, MI, USA.,Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA.,Obstetrics and Gynecology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - John D Meeker
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
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17
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Zhang H, Sanidad KZ, Zhu L, Parsonnet J, Haggerty TD, Zhang G, Cai Z. Frequent occurrence of triclosan hydroxylation in mammals: A combined theoretical and experimental investigation. JOURNAL OF HAZARDOUS MATERIALS 2021; 407:124803. [PMID: 33338815 DOI: 10.1016/j.jhazmat.2020.124803] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 11/07/2020] [Accepted: 12/06/2020] [Indexed: 06/12/2023]
Abstract
Triclosan (TCS) is a widespread antimicrobial agent with many adverse health risks. Its hepatoxicity invariably points to the activation of constitutive androstane receptor (CAR), which regulates cytochrome P450 (CYP) genes that are critical for oxidative metabolism. Here, we provide the theoretical and experimental evidences showing that metabolic activation of TCS frequently occurs through aromatic hydroxylation in mammals. CYP-mediated oxidation was predicted to take place at each aromatic C‒H bond. Molecular docking and in vitro approaches reveal oxidative reaction could be efficiently catalyzed by CAR-regulated CYP2B6 enzyme. Parallel reaction monitoring (PRM) high-resolution mass spectrometry was utilized to identify and profile TCS oxidative metabolites in paired mouse liver, bile, feces, plasma and urine. We found multiple hydroxylated isomers including the products generated via the NIH shift of chlorine, as well as their subsequent conjugates. These metabolites showed isomer-specific retention in mice. Glucuronide conjugates are more readily excreted than the sulfates. Moreover, for the first time, isomeric hydroxylated metabolites were detected in the urine and stool of human subjects used TCS-contained household and personal care products. Collectively, these findings suggest that hydroxylation is an important, yet often underestimated element that worth considering to fully evaluate the biological fates and health risks of TCS.
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Affiliation(s)
- Hongna Zhang
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 999077 Hong Kong, China
| | - Katherine Z Sanidad
- Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA; Molecular and Cellular Biology Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Lin Zhu
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 999077 Hong Kong, China
| | - Julie Parsonnet
- Department of Medicine and Department of Health Research and Policy, Stanford University, Stanford, CA 94305, USA
| | - Thomas D Haggerty
- Department of Medicine and Department of Health Research and Policy, Stanford University, Stanford, CA 94305, USA
| | - Guodong Zhang
- Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA; Molecular and Cellular Biology Program, University of Massachusetts, Amherst, MA 01003, USA.
| | - Zongwei Cai
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, 999077 Hong Kong, China.
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18
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40 Years of Research on Polybrominated Diphenyl Ethers (PBDEs)-A Historical Overview and Newest Data of a Promising Anticancer Drug. Molecules 2021; 26:molecules26040995. [PMID: 33668501 PMCID: PMC7918430 DOI: 10.3390/molecules26040995] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/29/2021] [Accepted: 02/10/2021] [Indexed: 12/11/2022] Open
Abstract
Polybrominated diphenyl ethers (PBDEs) are a group of molecules with an ambiguous background in literature. PBDEs were first isolated from marine sponges of Dysidea species in 1981 and have been under continuous research to the present day. This article summarizes the two research aspects, (i) the marine compound chemistry research dealing with naturally produced PBDEs and (ii) the environmental toxicology research dealing with synthetically-produced brominated flame-retardant PBDEs. The different bioactivity patterns are set in relation to the structural similarities and dissimilarities between both groups. In addition, this article gives a first structure-activity relationship analysis comparing both groups of PBDEs. Moreover, we provide novel data of a promising anticancer therapeutic PBDE (i.e., 4,5,6-tribromo-2-(2',4'-dibromophenoxy)phenol; termed P01F08). It has been known since 1995 that P01F08 exhibits anticancer activity, but the detailed mechanism remains poorly understood. Only recently, Mayer and colleagues identified a therapeutic window for P01F08, specifically targeting primary malignant cells in a low µM range. To elucidate the mechanistic pathway of cell death induction, we verified and compared its cytotoxicity and apoptosis induction capacity in Ramos and Jurkat lymphoma cells. Moreover, using Jurkat cells overexpressing antiapoptotic Bcl-2, we were able to show that P01F08 induces apoptosis mainly through the intrinsic mitochondrial pathway.
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19
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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: 27] [Impact Index Per Article: 9.0] [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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20
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Khidkhan K, Mizukawa H, Ikenaka Y, Nakayama SMM, Nomiyama K, Yokoyama N, Ichii O, Takiguchi M, Tanabe S, Ishizuka M. Altered hepatic cytochrome P450 expression in cats after chronic exposure to decabromodiphenyl ether (BDE-209). J Vet Med Sci 2020; 82:978-982. [PMID: 32435004 PMCID: PMC7399315 DOI: 10.1292/jvms.20-0140] [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: 11/22/2022] Open
Abstract
The knowledge of cytochrome P450 (CYP) expression involved in chemical exposure are necessary in clinical applications for the medication and prediction of adverse effects. The
aim of this study was to evaluate the mRNA expression of CYP1–CYP3 families in cats exposed to BDE-209 for one year. All selected CYP isoforms showed no significant difference in
mRNA expressions between control and exposure groups, however, CYP3A12 and CYP3A131 revealed tend to be two times higher in the exposure group compared to control group. The
present results indicate that the chronic exposure of BDE209 could not alter CYP expression in the liver of cats. This result considered caused by the deficiency of CYP2B subfamily
which is major metabolism enzyme of polybrominated diphenyl ethers (PBDEs) in cat.
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Affiliation(s)
- Kraisiri Khidkhan
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan
| | - Hazuki Mizukawa
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan.,Department of Science and Technology for Biological Resources and Environment, Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan
| | - Yoshinori Ikenaka
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan.,Water Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa
| | - Shouta M M Nakayama
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan
| | - Kei Nomiyama
- Center for Marine Environmental Studies (CMES), Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Nozomu Yokoyama
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan
| | - Osamu Ichii
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan.,Laboratory of Agrobiomedical Science, Faculty of Agriculture, Hokkaido University, Kita 9, Nishi 9, Sapporo, Hokkaido 060-8589, Japan
| | - Mitsuyoshi Takiguchi
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan
| | - Shinsuke Tanabe
- Center for Marine Environmental Studies (CMES), Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Mayumi Ishizuka
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan
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21
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Poston RG, Murphy L, Rejepova A, Ghaninejad-Esfahani M, Segales J, Mulligan K, Saha RN. Certain ortho-hydroxylated brominated ethers are promiscuous kinase inhibitors that impair neuronal signaling and neurodevelopmental processes. J Biol Chem 2020; 295:6120-6137. [PMID: 32229587 PMCID: PMC7196656 DOI: 10.1074/jbc.ra119.011138] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 03/23/2020] [Indexed: 12/20/2022] Open
Abstract
The developing nervous system is remarkably sensitive to environmental signals, including disruptive toxins, such as polybrominated diphenyl ethers (PBDEs). PBDEs are an environmentally pervasive class of brominated flame retardants whose neurodevelopmental toxicity mechanisms remain largely unclear. Using dissociated cortical neurons from embryonic Rattus norvegicus, we found here that chronic exposure to 6-OH-BDE-47, one of the most prevalent hydroxylated PBDE metabolites, suppresses both spontaneous and evoked neuronal electrical activity. On the basis of our previous work on mitogen-activated protein kinase (MAPK)/extracellular signal-related kinase (ERK) (MEK) biology and our observation that 6-OH-BDE-47 is structurally similar to kinase inhibitors, we hypothesized that certain hydroxylated PBDEs mediate neurotoxicity, at least in part, by impairing the MEK-ERK axis of MAPK signal transduction. We tested this hypothesis on three experimental platforms: 1) in silico, where modeling ligand-protein docking suggested that 6-OH-BDE-47 is a promiscuous ATP-competitive kinase inhibitor; 2) in vitro in dissociated neurons, where 6-OH-BDE-47 and another specific hydroxylated BDE metabolite similarly impaired phosphorylation of MEK/ERK1/2 and activity-induced transcription of a neuronal immediate early gene; and 3) in vivo in Drosophila melanogaster, where developmental exposures to 6-OH-BDE-47 and a MAPK inhibitor resulted in offspring displaying similarly increased frequency of mushroom-body β-lobe midline crossing, a metric of axonal guidance. Taken together, our results support that certain ortho-hydroxylated PBDE metabolites are promiscuous kinase inhibitors and can cause disruptions of critical neurodevelopmental processes, including neuronal electrical activity, pre-synaptic functions, MEK-ERK signaling, and axonal guidance.
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Affiliation(s)
- Robert G Poston
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, Merced, California 95343
| | - Lillian Murphy
- Department of Biological Sciences, Center for Interdisciplinary Molecular Biology: Education, Research and Advancement (CIMERA), California State University, Sacramento, California 95819
| | - Ayna Rejepova
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, Merced, California 95343
| | - Mina Ghaninejad-Esfahani
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, Merced, California 95343
| | - Joshua Segales
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, Merced, California 95343
| | - Kimberly Mulligan
- Department of Biological Sciences, Center for Interdisciplinary Molecular Biology: Education, Research and Advancement (CIMERA), California State University, Sacramento, California 95819
| | - Ramendra N Saha
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, Merced, California 95343.
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22
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Ma G, Yu H, Han C, Jia Y, Wei X, Wang Z. Binding and Metabolism of Brominated Flame Retardant β-1,2-Dibromo-4-(1,2-dibromoethyl)cyclohexane in Human Microsomal P450 Enzymes: Insights from Computational Studies. Chem Res Toxicol 2020; 33:1487-1496. [DOI: 10.1021/acs.chemrestox.0c00076] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Guangcai Ma
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Haiying Yu
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Cenyang Han
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Yue Jia
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Xiaoxuan Wei
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Zhiguo Wang
- Institute of Ageing Research, School of Medicine, Hangzhou Normal University, Hangzhou 311121, China
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23
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Butryn DM, Chi LH, Gross MS, McGarrigle B, Schecter A, Olson JR, Aga DS. Retention of polybrominated diphenyl ethers and hydroxylated metabolites in paired human serum and milk in relation to CYP2B6 genotype. JOURNAL OF HAZARDOUS MATERIALS 2020; 386:121904. [PMID: 31901712 DOI: 10.1016/j.jhazmat.2019.121904] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/30/2019] [Accepted: 12/14/2019] [Indexed: 05/06/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) and their hydroxylated metabolites (OH-BDEs) are endocrine disrupting compounds prevalent in human serum and breast milk. Retention of PBDEs and OH-BDEs in humans may be affected by differences in PBDE metabolism due to variants in cytochrome P450 2B6 (CYP2B6). The objectives of this study are to assess the partitioning profiles of PBDEs and OH-BDEs in forty-eight paired human serum and milk samples, and to evaluate the relationship between variants in CYP2B6 genotype and PBDE and OH-BDE accumulation in humans. Results show that the geometric mean (GM) concentrations of PBDEs are similar in serum (GM = 43.4 ng/g lipid) and milk samples (GM = 52.9 ng/g lipid), while OH-BDEs are retained primarily in serum (GM = 2.31 ng/g lipid), compared to milk (GM = 0.045 ng/g lipid). Participants with CYP2B6*6 genotype had a greater relative retention of PBDEs in serum and milk, and significant relationships (p < 0.05) were also observed for PBDE-47, 5-OH-BDE-47 and 6-OH-BDE-47 concentrations relative to CYP2B6*5 and CYP2B6*6 genotypes. These results are the first to show that CYP2B6 genotype is significantly related to the relative retention of PBDEs in humans, which may have direct implications for variability in the susceptibility of individuals to the potential adverse effects of these contaminants.
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Affiliation(s)
- Deena M Butryn
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, 611 Natural Sciences Complex, Buffalo, NY, 14260, USA
| | - Lai-Har Chi
- Department of Pharmacology and Toxicology, University at Buffalo, The State University of New York. 102 Farber Hall, 3435 Main St, Buffalo, NY, 14214, USA; Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York, 102 Farber Hall, 3435 Main St, Buffalo, NY, 14214, USA
| | - Michael S Gross
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, 611 Natural Sciences Complex, Buffalo, NY, 14260, USA
| | - Barbara McGarrigle
- Department of Pharmacology and Toxicology, University at Buffalo, The State University of New York. 102 Farber Hall, 3435 Main St, Buffalo, NY, 14214, USA; Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York, 102 Farber Hall, 3435 Main St, Buffalo, NY, 14214, USA
| | - Arnold Schecter
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, 323 East Chesnut Street, Louisville, KY, 40202, USA; University of Louisville School of Public Health and Information Sciences, 485 E Gray St. Louisville, KY, 40202, USA
| | - James R Olson
- Department of Pharmacology and Toxicology, University at Buffalo, The State University of New York. 102 Farber Hall, 3435 Main St, Buffalo, NY, 14214, USA; Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York, 102 Farber Hall, 3435 Main St, Buffalo, NY, 14214, USA
| | - Diana S Aga
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, 611 Natural Sciences Complex, Buffalo, NY, 14260, USA.
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24
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Liu Y, Feng Y, Li J, Zhou D, Guo R, Ji R, Chen J. The bioaccumulation, elimination, and trophic transfer of BDE-47 in the aquatic food chain of Chlorella pyrenoidosa-Daphnia magna. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 258:113720. [PMID: 31831226 DOI: 10.1016/j.envpol.2019.113720] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 11/25/2019] [Accepted: 12/01/2019] [Indexed: 06/10/2023]
Abstract
As a persistent organic pollutant, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) has been widely detected in aquatic environments. However, studies on the fate and transfer of BDE-47 in the aquatic food chain remain scarce. In this study, we investigated the bioaccumulation and elimination of BDE-47 in Chlorella pyrenoidosa, as well as the trophic transfer and biomagnification of BDE-47 in the "C. pyrenoidosa-Daphnia magna" food chain, using C-14 radioactive tracer technology. After 96 h of BDE-47 exposure, the algae accumulated 88.98% ± 0.59% of the initial radioactivity from the medium, and 36.09% ± 9.22% of the accumulated residues in the algae occurred in the form of bound residues. During 96 h of elimination, only 13% ± 0.50% of accumulated radioactivity in the algae was released into the medium. After 24 h of exposure, D. magna accumulated 35.99% ± 2.55% of the initial radioactivity via water filtration from the medium, and 31.35% ± 1.92% of the accumulated radioactivity in D. magna occurred as bound residues. However, D. magna accumulated 66.89% ± 2.37% of the accumulated radioactivity in the algae via food uptake from the contaminated algae, with a high portion of radioactivity observed as bound residues (83.40% ± 0.97% of accumulated radioactivity in D. magna). This indicated a reduction in the environmental risk of BDE-47. There was obvious biomagnification in the food chain between C. pyrenoidosa and D. magna (biomagnification factors, BMFs>1), resulting in environmental hazard transfer in the aquatic food chain. However, no metabolite was found during the exposure experiment, and further studies should be carried out to investigate the intrinsic mechanisms of the trophic transfer of BDE-47, especially in multilevel food chains. Therefore, this study elucidated the effect of dietary uptake on the bioaccumulation of BDE-47 in D. magna and provided new insight for future analysis regarding the bioaccumulation and biomagnification of organic pollutants in the food chain.
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Affiliation(s)
- Yanhua Liu
- School of Engineering, China Pharmaceutical University, Nanjing, 211198, China
| | - Yinmei Feng
- School of Engineering, China Pharmaceutical University, Nanjing, 211198, China
| | - Jinrong Li
- School of Engineering, China Pharmaceutical University, Nanjing, 211198, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Dashun Zhou
- School of Engineering, China Pharmaceutical University, Nanjing, 211198, China
| | - Ruixin Guo
- School of Engineering, China Pharmaceutical University, Nanjing, 211198, China
| | - Rong Ji
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Jianqiu Chen
- School of Engineering, China Pharmaceutical University, Nanjing, 211198, China.
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25
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Zhang M, Guo W, Wei J, Shi J, Zhang J, Ge H, Tao H, Liu X, Hu Q, Cai Z. Determination of newly synthesized dihydroxylated polybrominated diphenyl ethers in sea fish by gas chromatography-tandem mass spectrometry. CHEMOSPHERE 2020; 240:124878. [PMID: 31563719 DOI: 10.1016/j.chemosphere.2019.124878] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/14/2019] [Accepted: 09/14/2019] [Indexed: 06/10/2023]
Abstract
Dihydroxylated polybrominated diphenyl ethers (diOH-PBDEs) can be natural products of marine organisms or the metabolites of PBDEs. The optimal determination method and concentration of diOH-PBDEs in seafood are unknown due to a lack of commercially available standards. In the present study, diOH-PBDEs were synthesized, and an efficient measurement method for OH-PBDEs and diOH-PBDEs in sea fish muscle samples, including extraction, clean-up and gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis, was established. Pressurized liquid extraction (PLE) followed by partitioning with a KOH solution and florisil cartridge clean-up proved to be a reliable and robust method for detecting all OH-PBDEs/diOH-PBDEs. GC-MS/MS with an electron ionization (EI) source analysis was a sensitive analytical instrument for OH-PBDEs/diOH-PBDEs. The recovery using this method ranged from 19% to 101%, 28%-88% and 42%-90% for 10 ng, 20 ng and 40 ng spiking levels, respectively. The equipment detection limits (EDLs) were in the range of 0.31-2.78 pg/μL, and the limits of detection (LOD) for the method were in the range of 5.07-38.74 pg/g wet weight. Concentrations of diOH-PBDEs in the marine fish muscle samples were in the range of 32.43-1528.63 pg/g wet weight. Similar compositions of OH-PBDEs/diOH-PBDEs were found within the same family of marine fish.
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Affiliation(s)
- Mengtao Zhang
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China; China State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China
| | - Wei Guo
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Juntong Wei
- China State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China
| | - Jianghong Shi
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
| | - Jiawei Zhang
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Hui Ge
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Huanyu Tao
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xiaowei Liu
- Hefei University of Technology (Xuancheng Campus) Xuancheng, China
| | - Qing Hu
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Zongwei Cai
- China State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China.
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26
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Robinson JF, Kapidzic M, Hamilton EG, Chen H, Puckett KW, Zhou Y, Ona K, Parry E, Wang Y, Park JS, Costello JF, Fisher SJ. Genomic Profiling of BDE-47 Effects on Human Placental Cytotrophoblasts. Toxicol Sci 2019; 167:211-226. [PMID: 30202865 DOI: 10.1093/toxsci/kfy230] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Despite gradual legislative efforts to phase out flame retardants (FRs) from the marketplace, polybrominated diphenyl ethers (PBDEs) are still widely detected in human maternal and fetal tissues, eg, placenta, due to their continued global application in consumer goods and inherent biological persistence. Recent studies in rodents and human placental cell lines suggest that PBDEs directly cause placental toxicity. During pregnancy, trophoblasts play key roles in uterine invasion, vascular remodeling, and anchoring of the placenta-fetal unit to the mother. Thus, to study the potential consequences of PBDE exposures on human placental development, we used an in vitro model: primary villous cytotrophoblasts (CTBs). Following exposures, the endpoints that were evaluated included cytotoxicity, function (migration, invasion), the transcriptome, and the methylome. In a concentration-dependent manner, common PBDE congeners, BDE-47 and -99, significantly reduced cell viability and increased death. Upon exposures to sub-cytotoxic concentrations (≤ 5 µM), we observed BDE-47 accumulation in CTBs with limited evidence of metabolism. At a functional level, BDE-47 hindered the ability of CTBs to migrate and invade. Transcriptomic analyses of BDE-47 effects suggested concentration-dependent changes in gene expression, involving stress pathways, eg, inflammation and lipid/cholesterol metabolism as well as processes underlying trophoblast fate, eg, differentiation, migration, and vascular morphogenesis. In parallel assessments, BDE-47 induced low-level global increases in methylation of CpG islands, including a subset that were proximal to genes with roles in cell adhesion/migration. Thus, using a primary human CTB model, we showed that PBDEs induced alterations at cellular and molecular levels, which could adversely impact placental development.
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Affiliation(s)
- Joshua F Robinson
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143.,Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143
| | - Mirhan Kapidzic
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143.,Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143
| | - Emily G Hamilton
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143.,Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143
| | - Hao Chen
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143.,Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143
| | - Kenisha W Puckett
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143.,Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143
| | - Yan Zhou
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143.,Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143
| | - Katherine Ona
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143.,Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143
| | - Emily Parry
- Environmental Chemistry Laboratory, Department of Toxic Substances Control, California Environmental Protection Agency, Berkeley, California 94710
| | - Yunzhu Wang
- Environmental Chemistry Laboratory, Department of Toxic Substances Control, California Environmental Protection Agency, Berkeley, California 94710
| | - June-Soo Park
- Environmental Chemistry Laboratory, Department of Toxic Substances Control, California Environmental Protection Agency, Berkeley, California 94710
| | - Joseph F Costello
- Department of Neurological Surgery, University of California, San Francisco (UCSF), San Francisco, California 94158
| | - Susan J Fisher
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143.,Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, California 94143
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27
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Poston RG, Saha RN. Epigenetic Effects of Polybrominated Diphenyl Ethers on Human Health. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16152703. [PMID: 31362383 PMCID: PMC6695782 DOI: 10.3390/ijerph16152703] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/15/2019] [Accepted: 07/24/2019] [Indexed: 12/15/2022]
Abstract
Disruption of epigenetic regulation by environmental toxins is an emerging area of focus for understanding the latter's impact on human health. Polybrominated diphenyl ethers (PBDEs), one such group of toxins, are an environmentally pervasive class of brominated flame retardants that have been extensively used as coatings on a wide range of consumer products. Their environmental stability, propensity for bioaccumulation, and known links to adverse health effects have evoked extensive research to characterize underlying biological mechanisms of toxicity. Of particular concern is the growing body of evidence correlating human exposure levels to behavioral deficits related to neurodevelopmental disorders. The developing nervous system is particularly sensitive to influence by environmental signals, including dysregulation by toxins. Several major modes of actions have been identified, but a clear understanding of how observed effects relate to negative impacts on human health has not been established. Here, we review the current body of evidence for PBDE-induced epigenetic disruptions, including DNA methylation, chromatin dynamics, and non-coding RNA expression while discussing the potential relationship between PBDEs and neurodevelopmental disorders.
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Affiliation(s)
- Robert G Poston
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, CA 95343, USA
| | - Ramendra N Saha
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, CA 95343, USA.
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Cisneros KV, Agarwal V, James MO. Sulfonation and glucuronidation of hydroxylated bromodiphenyl ethers in human liver. CHEMOSPHERE 2019; 226:132-139. [PMID: 30925405 PMCID: PMC6516465 DOI: 10.1016/j.chemosphere.2019.03.103] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/12/2019] [Accepted: 03/14/2019] [Indexed: 06/09/2023]
Abstract
Hydroxylated bromodiphenyl ethers (OH-BDEs) can arise from monooxygenation of anthropogenic BDEs or through natural biosynthetic processes in marine organisms, and several OH-BDEs have been shown to be toxic. OH-BDEs are expected to form sulfate and glucuronide conjugates that are readily excreted, however there is little information on these pathways. We examined the human hepatic glucuronidation and sulfonation of 6-OH-BDE47, 2-OH-BDE68, 4-OH-BDE68 and 2-OH-6'methoxy-BDE68. Human liver microsomes and cytosol were from de-identified female and male donors aged 31 to 75 under an exempt protocol. Recombinant human SULT1A1, 1B1, 1E1 and 2A1 enzymes were prepared from bacterial expression systems. Sulfonation and glucuronidation of each OH-BDE were studied using radiolabeled co-substrates, 3'phosphoadenosine-5'phospho-35S-sulfate or uridine diphospho-β-D-14C-glucuronic acid in order to quantify the sulfated or glucuronidated products. The OH-BDEs studied were more efficiently glucuronidated than sulfonated. Of the compounds studied, 2-OH-BDE68 was the most readily conjugated, and exhibited an efficiency (Vmax/KM) of glucuronidation of 0.274 ± 0.125 mL/min/mg protein, mean ± S.D., n = 3, while that for sulfonation was 0.179 ± 0.030 mL/min/mg protein. For both pathways, all Km values were in the low μM range. Studies with human SULT enzymes showed that sulfonation of these four substrates was readily catalyzed by SULT1B1 and SULT1E1. Much lower activity was found with SULT1A1 and SULT2A1. Assuming that the glucuronide and sulfate conjugates are non-toxic and readily excreted, as is the case for most such conjugates, these studies suggest that OH-BDEs should not accumulate in people to the same extent as the parent BDEs.
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Affiliation(s)
- Katherine V Cisneros
- Department of Medicinal Chemistry, University of Florida, Gainesville, FL, 32610-0485, USA
| | - Vinayak Agarwal
- School of Chemistry and Biochemistry, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Margaret O James
- Department of Medicinal Chemistry, University of Florida, Gainesville, FL, 32610-0485, USA.
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Chen H, Seifikar H, Larocque N, Kim Y, Khatib I, Fernandez CJ, Abello N, Robinson JF. Using a Multi-Stage hESC Model to Characterize BDE-47 Toxicity during Neurogenesis. Toxicol Sci 2019; 171:221-234. [PMID: 31173147 PMCID: PMC6736394 DOI: 10.1093/toxsci/kfz136] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 04/20/2019] [Accepted: 05/22/2019] [Indexed: 12/20/2022] Open
Abstract
While the ramifications associated with polybrominated diphenyl ethers (PBDE) exposures during human pregnancy have yet to be determined, increasing evidence in humans and animal models suggests that these compounds cause neurodevelopmental toxicity. Human embryonic stem cell models (hESCs) can be used to study the effects of environmental chemicals throughout the successive stages of neuronal development. Here, using a hESC differentiation model, we investigated the effects of common PBDE congeners (BDE-47 or -99) on the successive stages of early neuronal development. First, we determined the points of vulnerability to PBDEs across four stages of in vitro neural development by using assays to assess for cytotoxicity. Differentiated neural progenitors were identified to be more sensitive to PBDEs than their less differentiated counterparts. In follow-up investigations, we observed BDE-47 to inhibit functional processes critical for neurogenesis (e.g., proliferation, expansion) in hESC-derived neural precursor cells (NPCs) at sub-lethal concentrations. Finally, to determine the mechanism(s) underlying PBDE-toxicity, we conducted global transcriptomic and methylomic analyses of BDE-47. We identified 589 genes to be differentially expressed (DE) due to BDE-47 exposure, including molecules involved in oxidative stress mediation, cell cycle, hormone signaling, steroid metabolism, and neurodevelopmental pathways. In parallel analyses, we identified a broad significant increase in CpG methylation. In summary our results suggest, on a cellular level, PBDEs induce human neurodevelopmental toxicity in a concentration-dependent manner and sensitivity to these compounds is dependent on the developmental stage of exposure. Proposed mRNA and methylomic perturbations may underlie toxicity in early embryonic neuronal populations.
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Affiliation(s)
- Hao Chen
- Center for Reproductive Sciences and Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Helia Seifikar
- Center for Reproductive Sciences and Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Nicholas Larocque
- Center for Reproductive Sciences and Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Yvonne Kim
- Center for Reproductive Sciences and Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Ibrahim Khatib
- Center for Reproductive Sciences and Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Charles J Fernandez
- Center for Reproductive Sciences and Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Nicomedes Abello
- Center for Reproductive Sciences and Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Joshua F Robinson
- Center for Reproductive Sciences and Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco (UCSF), San Francisco, CA, USA
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Zhang F, Peng L, Huang Y, Lin X, Zhou L, Chen J. Chronic BDE-47 Exposure Aggravates Malignant Phenotypes and Chemoresistance by Activating ERK Through ERα and GPR30 in Endometrial Carcinoma. Front Oncol 2019; 9:1079. [PMID: 31737560 PMCID: PMC6834531 DOI: 10.3389/fonc.2019.01079] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Accepted: 09/30/2019] [Indexed: 02/05/2023] Open
Abstract
Environmental exposure to certain compounds contribute to cell plasticity, tumor progression and even chemoresistance. 2,2',4,4'-tetrabromo diphenyl ether (BDE-47), one of the most frequently detected polybrominated diphenyl ethers (PBDEs) in environmental and biological samples, is a known estrogen disruptor closely associated with the development of hormone-dependent cancers. However, the effect of BDE-47 on endometrial carcinoma (EC), an estrogen-dependent cancer, remains to be elucidated. Mechanisms of estrogen receptor α (ERα) and G-protein-coupled receptor-30 (GPR30) involved in BDE-47 carcinogenesis are yet to be identified. This study aims to investigate the effect of BDE-47 on the invasive phenotype of estrogen-dependent EC cells. BDE-47-treated cells, such as Ishikawa-BDE-47 and HEC-1B-BDE-47 cells, exhibited increased cell viability and enhanced metastatic ability. In vivo studies showed larger tumor volumes and more metastasis in mice injected with Ishikawa-BDE-47 cells compared with parental Ishikawa cells. MTT assay showed that BDE-47 exposure could attenuate sensitivity of EC cells to cisplatin or paclitaxel treatment in vitro. Western blotting revealed overexpression of ERα, GPR30, pEGFR (phosphorylated epidermal growth factor receptor), and pERK (phosphorylated extracellular-regulated protein kinase) in Ishikawa-BDE-47 and HEC-1B-BDE-47 cells. Knockdown of ERα or GPR30 by small interfering RNA reversed the stimulating effect of BDE-47 on cell growth, migration and invasion of EC cells. Additionally, treatment with pEGFR or pERK inhibitor impaired cell viability, migration and invasion in Ishikawa-BDE-47 and HEC-1B-BDE-47 cells. Overall, our results indicate that chronic BDE-47 exposure triggers phenotypic plasticity, promotes progression and even chemoresistance in EC cells, at least in part, via ERα/GPR30 and EGFR/ERK signaling pathways.
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Affiliation(s)
- Fan Zhang
- Oncology Research Laboratory, Cancer Hospital of Shantou University Medical College, Shantou, China
- Guangdong Provincial Key Laboratory for Breast Cancer Diagnosis and Treatment, Cancer Hospital of Shantou University Medical College, Shantou, China
| | - Lin Peng
- Department of Laboratory Medicine, Cancer Hospital of Shantou University Medical College, Shantou, China
| | - Yiteng Huang
- Health Care Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Xueqiong Lin
- Department of Laboratory Medicine, Cancer Hospital of Shantou University Medical College, Shantou, China
| | - Li Zhou
- Department of Gynecologic Oncology, Cancer Hospital of Shantou University Medical College, Shantou, China
- *Correspondence: Li Zhou
| | - Jiongyu Chen
- Oncology Research Laboratory, Cancer Hospital of Shantou University Medical College, Shantou, China
- Guangdong Provincial Key Laboratory for Breast Cancer Diagnosis and Treatment, Cancer Hospital of Shantou University Medical College, Shantou, China
- Jiongyu Chen
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Fu Z, Chen J. Xenobiotic Metabolism by Cytochrome P450 Enzymes: Insights Gained from Molecular Simulations. CHALLENGES AND ADVANCES IN COMPUTATIONAL CHEMISTRY AND PHYSICS 2019. [DOI: 10.1007/978-3-030-16443-0_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Alves A, Erratico C, Lucattini L, Cuykx M, Ballesteros-Gómez A, Leonards PEG, Voorspoels S, Covaci A. Mass spectrometric identification of in vitro-generated metabolites of two emerging organophosphate flame retardants: V6 and BDP. CHEMOSPHERE 2018; 212:1047-1057. [PMID: 30286534 DOI: 10.1016/j.chemosphere.2018.08.142] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/19/2018] [Accepted: 08/28/2018] [Indexed: 06/08/2023]
Abstract
The aim of the present study was to investigate the in vitro metabolism of two emerging organophosphate flame retardants, namely tetrekis(2-chlorethyl)dichloroisopentyldiphosphate (V6) and bisphenol-A bis-diphenyl phosphate (BDP) in human liver microsomes (HLMs), HLM S9 fractions and in human serum. In particular, the role of cytochrome P450 (CYPs) enzymes and/or paraoxonases (PONs) in the formation of V6 and BDP phase I metabolites was studied. Mono-, di-hydroxylated and hydrolytic phase I metabolites of V6 were mainly formed by CYPs in HLMs, while hydrolytic and O-dealkylated phase I metabolites of BDP were generated by PONs mainly in serum experiments. Limited number of glucuronidated and sulfated phase II metabolites were also identified for the two chemicals. The activity of seven recombinant CYPs (rCYPs) including rCYP1A2, rCYP2B6, rCYP2C9, rCYP2C19, rCYP2D6, rCYP2E1 and rCYP3A4 in the in vitro phase I metabolism of V6 and BDP was investigated. The formation of V6 metabolites was catalyzed by several enzymes, especially rCYP1A2 that was responsible for the exclusive formation of two metabolites, one primary (M1) and its secondary metabolite (M9). For BDP, only one phase I metabolite (MM1) was catalyzed by the seven rCYPs. Collectively, these results indicate that CYPs have a predominant role in the metabolism of V6, while PONs have a predominant role in BDP in vitro metabolism. These results are a starting point for future studies involving the study of the toxicity, bioaccumulation and in vivo biomonitoring of V6 and BDP.
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Affiliation(s)
- Andreia Alves
- Flemish Institute for Technological Research (VITO NV), Boeretang 200, 2400 Mol, Belgium
| | - Claudio Erratico
- Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium
| | - Luisa Lucattini
- Department of Environment and Health, Vrije Universiteit Amsterdam, De Boelelaan 1087, 1081 HV, Amsterdam, The Netherlands
| | - Matthias Cuykx
- Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium
| | - Ana Ballesteros-Gómez
- Department of Environment and Health, Vrije Universiteit Amsterdam, De Boelelaan 1087, 1081 HV, Amsterdam, The Netherlands; Department of Analytical Chemistry, Institute of Fine Chemistry and Nanochemistry, University of Córdoba, Marie Curie Building (Annex), Campus of Rabanales, 14071, Córdoba, Spain
| | - Pim E G Leonards
- Department of Environment and Health, Vrije Universiteit Amsterdam, De Boelelaan 1087, 1081 HV, Amsterdam, The Netherlands
| | - Stefan Voorspoels
- Flemish Institute for Technological Research (VITO NV), Boeretang 200, 2400 Mol, Belgium
| | - Adrian Covaci
- Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium.
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Crystal Structure of CYP2B6 in Complex with an Efavirenz Analog. Int J Mol Sci 2018; 19:ijms19041025. [PMID: 29596329 PMCID: PMC5979536 DOI: 10.3390/ijms19041025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 03/23/2018] [Accepted: 03/26/2018] [Indexed: 01/08/2023] Open
Abstract
The over two dozen CYP2B structures of human, rabbit, and woodrat enzymes solved in the last decade have significantly enhanced our understanding of the structure-function relationships of drug metabolizing enzymes. More recently, an important role has emerged for halogen-π interactions in the CYP2B6 active site in substrate selectivity, explaining in part the preference for halogenated ligands as substrates. The mechanism by which such ligands interact with CYP2B enzymes involves conserved phenylalanine side chains, in particular F108, F115, or F297, in the active site, which form π bonds with halogens. To illustrate such halogen-π interactions using drugs that are major substrates of CYP2B6, we present here a crystal structure of CYP2B6 in complex with an analog of the widely used anti-HIV drug efavirenz, which contains a methyl group in place of the carbonyl oxygen. The chlorine of the efavirenz analog forms a π bond with the aromatic ring of F108, whereas the putative metabolism site on the distal end of the molecule is oriented towards the heme iron. The crystal structure showcases how CYP2B6 accommodates this important drug analog of considerable size in the active site by movement of various side chains without substantially increasing the active site volume. Furthermore, the CYP2B6-efavirenz analog complex provides a useful platform to investigate computationally as well as biophysically the effect of genetic polymorphisms on binding of the widely studied efavirenz.
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Hou R, Huang C, Rao K, Xu Y, Wang Z. Characterized in Vitro Metabolism Kinetics of Alkyl Organophosphate Esters in Fish Liver and Intestinal Microsomes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3202-3210. [PMID: 29439571 DOI: 10.1021/acs.est.7b05825] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Tris(2-butoxyethyl) phosphate (TBOEP) and tris( n-butyl) phosphate (TNBP) are the most commonly used alkyl organophosphate esters (alkyl-OPEs), and they increasingly accumulate in organisms and create potential health hazards. This study examined the metabolism of TNBP and TBOEP in Carassius carassius liver and intestinal microsomes and the production of their corresponding monohydroxylated and dealkylated metabolites. After 140 min of incubation with fish liver microsomes, the rapid depletion of TNBP and TBOEP were both best fitted to the Michaelis-Menten model (at administrated concentrations ranging from 0.5 to 200 μM), with a CLint (intrinsic clearance) of 3.1 and 3.9 μL·min-1·mg-1 protein, respectively. But no significant ( P > 0.05) biotransformation was observed for these compounds in intestinal microsomes at any administrated concentrations. In fish liver microsomes assay, bis(2-butoxyethyl) hydroxyethyl phosphate (BBOEHEP) and bis(2-butoxyethyl) 3-hydroxyl-2-butoxyethyl phosphate (3-OH-TBOEP) were the most abundant metabolites of TBOEP, and dibutyl-3-hydroxybutyl phosphate (3-OH-TNBP) was the predominant metabolite of TNBP. Similarly, the apparent Vmax values (maximum metabolic rate) of BBOEHEP and 3-OH-TNBP were also respectively highest among those of other metabolites. Further inhibition studies were conducted to identify the specific cytochrome P450 (CYP450) isozymes involved in the metabolism of TNBP and TBOEP in liver microsomes. It was confirmed that CYP3A4 and CYP1A were the significant CYP450 isoforms catalyzing the metabolism of TNBP and TBOEP in fish liver microsomes. Overall, this study emphasized the importance of hydroxylated metabolites as biomarkers for alkyl-OPEs exposure, and further research is needed to validate the in vivo formation and toxicological implications of these metabolites.
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Affiliation(s)
- Rui Hou
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Chao Huang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Kaifeng Rao
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
| | - Yiping Xu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
| | - Zijian Wang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
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Chen C, Liu J, Halpert JR, Wilderman PR. Use of Phenoxyaniline Analogues To Generate Biochemical Insights into the Interactio n of Polybrominated Diphenyl Ether with CYP2B Enzymes. Biochemistry 2018; 57:817-826. [PMID: 29215266 DOI: 10.1021/acs.biochem.7b01024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Human hepatic cytochromes P450 (CYP) are integral to xenobiotic metabolism. CYP2B6 is a major catalyst of biotransformation of environmental toxicants, including polybrominated diphenyl ethers (PBDEs). CYP2B substrates tend to contain halogen atoms, but the biochemical basis for this selectivity and for species specific determinants of metabolism has not been identified. Spectral binding titrations and inhibition studies were performed to investigate interactions of rat CYP2B1, rabbit CYP2B4, and CYP2B6 with a series of phenoxyaniline (POA) congeners that are analogues of PBDEs. For most congeners, there was a <3-fold difference between the spectral binding constants (KS) and IC50 values. In contrast, large discrepancies between these values were observed for POA and 3-chloro-4-phenoxyaniline. CYP2B1 was the enzyme most sensitive to POA congeners, so the Val-363 residue from that enzyme was introduced into CYP2B4 or CYP2B6. This substitution partially altered the protein-ligand interaction profiles to make them more similar to that of CYP2B1. Addition of cytochrome P450 oxidoreductase (POR) to titrations of CYP2B6 with POA or 2'4'5'TCPOA decreased the affinity of both ligands for the enzyme. Addition of cytochrome b5 to a recombinant enzyme system containing POR and CYP2B6 increased the POA IC50 value and decreased the 2'4'5'TCPOA IC50 value. Overall, the inconsistency between KS and IC50 values for POA versus 2'4'5'TCPOA is largely due to the effects of redox partner binding. These results provide insight into the biochemical basis of binding of diphenyl ethers to human CYP2B6 and changes in CYP2B6-mediated metabolism that are dependent on POA congener and redox partner identity.
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Affiliation(s)
- Chao Chen
- University of Connecticut School of Pharmacy , Storrs, Connecticut 06269, United States
| | - Jingbao Liu
- University of Connecticut School of Pharmacy , Storrs, Connecticut 06269, United States
| | - James R Halpert
- University of Connecticut School of Pharmacy , Storrs, Connecticut 06269, United States
| | - P Ross Wilderman
- University of Connecticut School of Pharmacy , Storrs, Connecticut 06269, United States
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Li CY, Lee S, Cade S, Kuo LJ, Schultz IR, Bhatt DK, Prasad B, Bammler TK, Cui JY. Novel Interactions between Gut Microbiome and Host Drug-Processing Genes Modify the Hepatic Metabolism of the Environmental Chemicals Polybrominated Diphenyl Ethers. Drug Metab Dispos 2017; 45:1197-1214. [PMID: 28864748 DOI: 10.1124/dmd.117.077024] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 08/30/2017] [Indexed: 12/12/2022] Open
Abstract
The gut microbiome is a novel frontier in xenobiotic metabolism. Polybrominated diphenyl ethers (PBDEs), especially BDE-47 (2, 2', 4, 4'-tetrabromodiphenyl ether) and BDE-99 (2, 2', 4, 4',5-pentabromodiphenyl ether), are among the most abundant and persistent environmental contaminants that produce a variety of toxicities. Little is known about how the gut microbiome affects the hepatic metabolism of PBDEs and the PBDE-mediated regulation of drug-processing genes (DPGs) in vivo. The goal of this study was to determine the role of gut microbiome in modulating the hepatic biotransformation of PBDEs. Nine-week-old male C57BL/6J conventional (CV) or germ-free (GF) mice were treated with vehicle, BDE-47 or BDE-99 (100 μmol/kg) for 4 days. Following BDE-47 treatment, GF mice had higher levels of 5-OH-BDE-47 but lower levels of four other metabolites in liver than CV mice; whereas following BDE-99 treatment GF mice had lower levels of four minor metabolites in liver than CV mice. RNA sequencing demonstrated that the hepatic expression of DPGs was regulated by both PBDEs and enterotypes. Under basal conditions, the lack of gut microbiome upregulated the Cyp2c subfamily but downregulated the Cyp3a subfamily. Following PBDE exposure, certain DPGs were differentially regulated by PBDEs in a gut microbiome-dependent manner. Interestingly, the lack of gut microbiome augmented PBDE-mediated upregulation of many DPGs, such as Cyp1a2 and Cyp3a11 in mouse liver, which was further confirmed by targeted metabolomics. The lack of gut microbiome also augmented the Cyp3a enzyme activity in liver. In conclusion, our study has unveiled a novel interaction between gut microbiome and the hepatic biotransformation of PBDEs.
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Affiliation(s)
- Cindy Yanfei Li
- Department of Environmental and Occupational Health Sciences (C.Y.L., S.L., T.K.B., J.Y.C.), and Department of Pharmaceutics (D.K.B., B.P.), University of Washington, Seattle, Washington; and Pacific Northwest National Laboratory, Sequim, Washington (S.C., L.-J.K., I.R.S.)
| | - Soowan Lee
- Department of Environmental and Occupational Health Sciences (C.Y.L., S.L., T.K.B., J.Y.C.), and Department of Pharmaceutics (D.K.B., B.P.), University of Washington, Seattle, Washington; and Pacific Northwest National Laboratory, Sequim, Washington (S.C., L.-J.K., I.R.S.)
| | - Sara Cade
- Department of Environmental and Occupational Health Sciences (C.Y.L., S.L., T.K.B., J.Y.C.), and Department of Pharmaceutics (D.K.B., B.P.), University of Washington, Seattle, Washington; and Pacific Northwest National Laboratory, Sequim, Washington (S.C., L.-J.K., I.R.S.)
| | - Li-Jung Kuo
- Department of Environmental and Occupational Health Sciences (C.Y.L., S.L., T.K.B., J.Y.C.), and Department of Pharmaceutics (D.K.B., B.P.), University of Washington, Seattle, Washington; and Pacific Northwest National Laboratory, Sequim, Washington (S.C., L.-J.K., I.R.S.)
| | - Irvin R Schultz
- Department of Environmental and Occupational Health Sciences (C.Y.L., S.L., T.K.B., J.Y.C.), and Department of Pharmaceutics (D.K.B., B.P.), University of Washington, Seattle, Washington; and Pacific Northwest National Laboratory, Sequim, Washington (S.C., L.-J.K., I.R.S.)
| | - Deepak K Bhatt
- Department of Environmental and Occupational Health Sciences (C.Y.L., S.L., T.K.B., J.Y.C.), and Department of Pharmaceutics (D.K.B., B.P.), University of Washington, Seattle, Washington; and Pacific Northwest National Laboratory, Sequim, Washington (S.C., L.-J.K., I.R.S.)
| | - Bhagwat Prasad
- Department of Environmental and Occupational Health Sciences (C.Y.L., S.L., T.K.B., J.Y.C.), and Department of Pharmaceutics (D.K.B., B.P.), University of Washington, Seattle, Washington; and Pacific Northwest National Laboratory, Sequim, Washington (S.C., L.-J.K., I.R.S.)
| | - Theo K Bammler
- Department of Environmental and Occupational Health Sciences (C.Y.L., S.L., T.K.B., J.Y.C.), and Department of Pharmaceutics (D.K.B., B.P.), University of Washington, Seattle, Washington; and Pacific Northwest National Laboratory, Sequim, Washington (S.C., L.-J.K., I.R.S.)
| | - Julia Yue Cui
- Department of Environmental and Occupational Health Sciences (C.Y.L., S.L., T.K.B., J.Y.C.), and Department of Pharmaceutics (D.K.B., B.P.), University of Washington, Seattle, Washington; and Pacific Northwest National Laboratory, Sequim, Washington (S.C., L.-J.K., I.R.S.)
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Krieger LK, Szeitz A, Bandiera SM. Hepatic microsomal metabolism of BDE-47 and BDE-99 by lesser snow geese and Japanese quail. CHEMOSPHERE 2017; 182:559-566. [PMID: 28525869 DOI: 10.1016/j.chemosphere.2017.05.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/02/2017] [Accepted: 05/03/2017] [Indexed: 06/07/2023]
Abstract
In the present study, we investigated the oxidative biotransformation of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and 2,2',4,4',5-pentabromodiphenyl ether (BDE-99) by liver microsomes from wild lesser snow geese (Chen caerulescens caerulescens) and domesticated Japanese quail (Coturnix japonica). Formation of hydroxy-metabolites was analyzed using an ultra-high performance liquid chromatography-tandem mass spectrometry-based method. Incubation of BDE-47 with avian liver microsomes produced sixteen hydroxy-metabolites, eight of which were identified using authentic standards. The major metabolites formed by liver microsomes from individual lesser snow geese were 4-hydroxy-2,2',3,4'-tetrabromodiphenyl ether (4-OH-BDE-42), 3-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (3-OH-BDE-47), and 4'-hydroxy-2,2',4,5'-tetrabromodiphenyl ether (4'-OH-BDE-49). By comparison, 4-OH-BDE-42 and 4'-OH-BDE-49, but not 3-OH-BDE-47, were major metabolites of Japanese quail liver microsomes. Unidentified metabolites included monohydroxy- and dihydroxy-tetrabromodiphenyl ethers. Incubation of BDE-99 with avian liver microsomes produced seventeen hydroxy-metabolites, twelve of which were identified using authentic standards. The major metabolites formed by lesser snow goose liver microsomes were 2,4,5-tribromophenol, 3-OH-BDE-47, 4'-OH-BDE-49, 4-hydroxy-2,2',3,4',5-pentabromodiphenyl ether (4-OH-BDE-90), and 5'-hydroxy-2,2',4,4',5-pentabromodiphenyl ether (5'-OH-BDE-99). By comparison, the major metabolites produced by liver microsomes from Japanese quail included 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE-47) and 2-hydroxy-2',3,4,4',5-pentabromodiphenyl ether (2-OH-BDE-123), but not 3-OH-BDE-47. Unidentified metabolites consisted of monohydroxy-pentabromodiphenyl ethers, monohydroxy-tetrabromodiphenyl ethers and dihydroxy-tetrabromodiphenyl ethers. Another difference between the two species was that formation rates of BDE-47 and BDE-99 metabolites were greater with liver microsomes from male than female Japanese quail, but a sex difference was not observed with lesser snow geese.
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Affiliation(s)
- Lisa K Krieger
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - András Szeitz
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Stelvio M Bandiera
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada.
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Xiang P, Liu RY, Sun HJ, Yang YW, Cui XY, Ma LQ. Effects of novel brominated flame retardant TBPH and its metabolite TBMEHP on human vascular endothelial cells: Implication for human health risks. ENVIRONMENTAL RESEARCH 2017; 156:834-842. [PMID: 28318508 DOI: 10.1016/j.envres.2017.02.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 02/23/2017] [Accepted: 02/24/2017] [Indexed: 06/06/2023]
Abstract
As a replacement for polybrominated diphenyl ethers, bis-(2-ethylhexyl) tetrabromophthalate (TBPH) is widely used as a novel flame retardant and has been detected in many environmental matrix including human blood. TBPH can be metabolized into mono-(2-ethyhexyl) tetrabromophthalate (TBMEHP) by carboxylesterase. However, their adverse effects on human vascular endothelium and their potential impacts on human cardiovascular disease are unknown. In this study, their adverse effects and associated molecular mechanisms on human vascular endothelial cells (HUVECs) were investigated. A concentration-dependent inhibition on HUVECs' viability and growth was observed for TBMEHP but not for TBPH. TBMEHP induced a marked G0/G1 cell cycle arrest and robust cell apoptosis at 1μg/mL by inducing expression of p53, GADD45α and cyclin dependent kinase (CDK) inhibitors (p21and p27) while suppressing the expression of cyclin D1, CDK2, CDK6, and Bcl-2. Unlike TBMEHP, TBPH caused early apoptosis after G2/M phase arrest only at 10μg/mL via up-regulation of p21 and down-regulation of CDK2 and CDK4. TBMEHP decreased mitochondrial membrane potential and increased caspase-3 activity at 1μg/mL, suggesting that activation of p53 and mitochondrial pathway were involved in the cell apoptosis. The data showed that TBPH and TBMEHP induced different cell cycle arrest and apoptosis through different molecular mechanisms with much higher toxicity for TBMEHP. Our study implies that the metabolites of TBPH, possibly other novel brominated flame retardants, may be of potential concern for human cardiovascular disease.
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Affiliation(s)
- Ping Xiang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, People's Republic of China
| | - Rong-Yan Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, People's Republic of China
| | - Hong-Jie Sun
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, People's Republic of China
| | - Yun-Wen Yang
- The State Key Laboratory of Pharmaceutical Biotechnology, College of Life Science, Nanjing University, Nanjing 210046, People's Republic of China
| | - Xin-Yi Cui
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, People's Republic of China.
| | - Lena Q Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, People's Republic of China; Soil and Water Science Department, University of Florida, Gainesville, FL 32611, United States.
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Shah MB, Liu J, Zhang Q, Stout CD, Halpert JR. Halogen-π Interactions in the Cytochrome P450 Active Site: Structural Insights into Human CYP2B6 Substrate Selectivity. ACS Chem Biol 2017; 12:1204-1210. [PMID: 28368100 DOI: 10.1021/acschembio.7b00056] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Numerous cytochrome P450 (CYP) 2B6 substrates including drugs and environmental chemicals are halogenated. To assess the role of halogen-π bonds in substrate selectivity and orientation in the active site, structures of four CYP2B6 monoterpenoid complexes were solved by X-ray crystallography. Bornyl bromide exhibited dual orientations in the active site with the predominant orientation revealing a bromine-π bond with the Phe108 side chain. Bornane demonstrated two orientations with equal occupancy; in both, the C2 atom that bears the bromine in bornyl bromide was displaced by more than 2.5 Å compared with the latter complex. The bromine in myrtenyl bromide π-bonded with Phe297 in CYP2B6, whereas the two major orientations in the active site mutant I114V exhibited bromine-π interactions with two additional residues, Phe108 and Phe115. Analysis of existing structures suggests that halogen-π interactions may be unique to the CYP2B enzymes within CYP family 2 but are also important for CYP3A enzymes.
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Affiliation(s)
- Manish B. Shah
- School
of Pharmacy, University of Connecticut, Storrs, Connecticut, United States
| | - Jingbao Liu
- School
of Pharmacy, University of Connecticut, Storrs, Connecticut, United States
| | - Qinghai Zhang
- The
Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, United States
| | - C. David Stout
- The
Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, United States
| | - James R. Halpert
- School
of Pharmacy, University of Connecticut, Storrs, Connecticut, United States
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Uptake and biotransformation of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) in four marine microalgae species. Sci Rep 2017; 7:44263. [PMID: 28287149 PMCID: PMC5347160 DOI: 10.1038/srep44263] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 02/07/2017] [Indexed: 11/30/2022] Open
Abstract
Hydroxylated- and methoxylated- polybrominated diphenyl ethers (OH-PBDEs and MeO-PBDEs) are more toxic than PBDEs and occur widely in the marine environment, and yet their origins remain controversial. In this study, four species of microalgae (Isochrysis galbana, Prorocentrum minimum, Skeletonema grethae and Thalassiosira pseudonana) were exposed to BDE-47, which is synthetic and is the predominant congener of PBDEs in the environment. By chemical analysis after incubation of 2 to 6 days, the efficiency of uptake of BDE-47 and, more importantly, the potential of undergoing biotransformation to form OH-PBDEs and MeO-PBDEs by the microalgae were investigated. Growth rates of these axenic microalgae were not affected upon exposure to environmentally relevant concentrations (0.2–20 μg BDE-47 L−1), and accumulation ranged from 0.772 ± 0.092 μg BDE-47 g−1 lipid to 215 ± 54 μg BDE-47 g−1 lipid within 2 days. Debromination of BDE-47 and formation of BDE-28 occurred in all microalgae species (0.01 to 0.87%), but biotransformation to OH-PBDEs was only found in I. galbana upon exposure to extremely high concentration. The results of this study showed that biotransformation of microalgae species is unlikely an explanation for the OH-PBDEs and MeO-PBDEs found in the marine environment.
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Chen X, Lin Y, Dang K, Puschner B. Quantification of Polychlorinated Biphenyls and Polybrominated Diphenyl Ethers in Commercial Cows' Milk from California by Gas Chromatography-Triple Quadruple Mass Spectrometry. PLoS One 2017; 12:e0170129. [PMID: 28085917 PMCID: PMC5234792 DOI: 10.1371/journal.pone.0170129] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 12/29/2016] [Indexed: 12/04/2022] Open
Abstract
We determined 12 polybrominated diphenyl ethers (PBDEs) and 19 polychlorinated biphenyls (PCBs) congeners in eight different brands of commercial whole milk (WM) and fat free milk (FFM) produced and distributed in California. Congeners were extracted using a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method, purified by gel permeation chromatography, and quantified using gas chromatography-triple quadruple mass spectrometry. PBDEs and PCBs were detected in all FFM and WM samples. The most prevalent PBDE congeners in WM were BDE-47 (geometric mean: 18.0 pg/mL, 0.51 ng/g lipid), BDE-99 (geometric mean: 9.9 pg/mL, 0.28 ng/g lipid), and BDE-49 (geometric mean: 6.0 pg/mL, 0.17 ng/g lipid). The dominant PCB congeners in WM were PCB-101(geometric mean: 23.6 pg/mL, 0.67 ng/g lipid), PCB-118 (geometric mean: 25.2 pg/mL, 0.72 ng/g lipid), and PCB-138 (geometric mean: 25.3 pg/mL, 0.72 ng/g lipid). The sum of all 19 PCB congeners in FFM and WM were several orders of magnitude below the U.S. FDA tolerance. The sum of PBDEs in milk samples suggest close proximity to industrial emissions, and confirm previous findings of elevated PBDE levels in California compared to other regions in the United States.
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Affiliation(s)
- Xiaopeng Chen
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Yanping Lin
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Katherine Dang
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Birgit Puschner
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California, United States of America
- * E-mail:
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42
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Analysis of hydroxylated polybrominated diphenyl ethers (OH-BDEs) by supercritical fluid chromatography/mass spectrometry. Talanta 2016; 161:122-129. [DOI: 10.1016/j.talanta.2016.08.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/30/2016] [Accepted: 08/02/2016] [Indexed: 12/31/2022]
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Haraguchi K, Ito Y, Takagi M, Fujii Y, Harada KH, Koizumi A. Levels, profiles and dietary sources of hydroxylated PCBs and hydroxylated and methoxylated PBDEs in Japanese women serum samples. ENVIRONMENT INTERNATIONAL 2016; 97:155-162. [PMID: 27615405 DOI: 10.1016/j.envint.2016.08.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 08/03/2016] [Accepted: 08/24/2016] [Indexed: 06/06/2023]
Abstract
Human exposure to polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) may result in retention of specific congeners of hydroxylated PCBs (OH-PCBs) and hydroxylated/methoxylated PBDEs (OH-/MeO-PBDEs) in serum. However, dietary sources and biotransformation of OH-/MeO-PBDEs in humans are poorly understood. Therefore, this study was conducted to investigate the levels, profiles, and exposure sources of OH-/MeO-PBDEs along with OH-PCBs present in human serum. Twenty serum samples pooled from women of four age groups (30s/40s/50s/60s) living in four districts of Japan were analyzed for OH-/MeO-PBDEs, and their profiles were then compared with those of seafood (seaweed and fish). The major component of OH-PCBs in the phenolic fraction of serum was 4-OH-CB187 (mean: 85pgg-1 wet weight (ww)). Total OH-PCBs accounted for about 1/20 of the total PCBs (mean; 1800pgg-1 ww). In contrast, the predominant component of OH-PBDEs in serum was 6-OH-BDE47 (mean: 183pgg-1 ww), which was about 20-fold higher than BDE-47 (mean; 8.7pgg-1 ww). In the neutral fraction, 2'-MeO-BDE68 was primarily found at a similar concentration (mean 5.6pgg-1 ww) to BDE-47. Both 4-OH-PCB187 and 2'-MeO-BDE68 were significantly correlated with woman's age (p<0.01), but not with 6-OH-BDE47 or BDE-47. The profiles of OH-PBDEs in serum were consistent with those in edible seaweeds (Sargassum fusiforme) sold for human consumption, whereas MeO-PBDEs had a similar profile as those in edible fish (Serranidae sp.) from Japanese coastal waters. These findings indicate that the profiles of OH-PBDEs and MeO-PBDEs in Japanese serum are different from those in other countries, and their sources may be specific edible seaweeds and fish, respectively. This is the first report of profiles and dietary sources of OH/MeO-PBDEs in human serum from Japan.
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Affiliation(s)
- Koichi Haraguchi
- Daiichi College of Pharmaceutical Sciences, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511, Japan.
| | - Yoshiko Ito
- Daiichi College of Pharmaceutical Sciences, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511, Japan
| | - Masae Takagi
- Daiichi College of Pharmaceutical Sciences, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511, Japan
| | - Yukiko Fujii
- Daiichi College of Pharmaceutical Sciences, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511, Japan; Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Yoshida, Kyoto 606-8501, Japan
| | - Kouji H Harada
- Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Yoshida, Kyoto 606-8501, Japan
| | - Akio Koizumi
- Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Yoshida, Kyoto 606-8501, Japan
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44
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Yost AT, Thornton LM, Venables BJ, Sellin Jeffries MK. Dietary exposure to polybrominated diphenyl ether 47 (BDE-47) inhibits development and alters thyroid hormone-related gene expression in the brain of Xenopus laevis tadpoles. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2016; 48:237-244. [PMID: 27838513 DOI: 10.1016/j.etap.2016.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 10/28/2016] [Accepted: 11/01/2016] [Indexed: 06/06/2023]
Abstract
Few studies have investigated the thyroid-disrupting effects of polybrominated diphenyl ethers (PBDEs) across multiple levels of biological organization in anurans, despite their suitability for the screening of thyroid disruptors. Therefore, the present study evaluated the effects of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on development, thyroid histology and thyroid hormone-related gene expression in Xenopus laevis exposed to 0 (control), 50 (low), 500 (medium) or 5000μg BDE-47/g food (high) for 21days. Only the high dose of BDE-47 hindered growth and development; however, thyroid hormone-associated gene expression was downregulated in the brains of tadpoles regardless of dose. These results show that BDE-47 disrupts thyroid hormone signaling at the molecular and whole-organism levels and suggest that gene expression in the brain is a more sensitive endpoint than metamorphosis. Furthermore, the altered gene expression patterns among BDE-47-exposed tadpoles provide insight into the mechanisms of PBDE-induced thyroid disruption and highlight the potential for PBDEs to act as neurodevelopmental toxicants.
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Affiliation(s)
- Alexandra T Yost
- Department of Biology, Texas Christian University, Fort Worth, TX, 76129, USA
| | - Leah M Thornton
- Department of Biology, Texas Christian University, Fort Worth, TX, 76129, USA
| | - Barney J Venables
- Department of Biological Sciences, University of North Texas, Denton, TX, 76203, USA
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45
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Marchitti SA, Mazur CS, Dillingham CM, Rawat S, Sharma A, Zastre J, Kenneke JF. Inhibition of the Human ABC Efflux Transporters P-gp and BCRP by the BDE-47 Hydroxylated Metabolite 6-OH-BDE-47: Considerations for Human Exposure. Toxicol Sci 2016; 155:270-282. [PMID: 28031414 DOI: 10.1093/toxsci/kfw209] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
High body burdens of polybrominated diphenyl ethers (PBDEs) in infants and young children have led to increased concern over their potential impact on human development. PBDE exposure can alter the expression of genes involved in thyroid homeostasis, including those of ATP-binding cassette (ABC) transporters, which mediate cellular xenobiotic efflux. However, little information exists on how PBDEs interact with ABC transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP). The purpose of this study was to evaluate the interactions of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and its hydroxylated metabolite 6-OH-BDE-47 with P-gp and BCRP, using human MDR1- and BCRP-expressing membrane vesicles and stably transfected NIH-3T3-MDR1 and MDCK-BCRP cells. In P-gp membranes, BDE-47 did not affect P-gp activity; however, 6-OH-BDE-47 inhibited P-gp activity at low µM concentrations (IC50 = 11.7 µM). In BCRP membranes, BDE-47 inhibited BCRP activity; however, 6-OH-BDE-47 was a stronger inhibitor [IC50 = 45.9 µM (BDE-47) vs. IC50 = 9.4 µM (6-OH-BDE-47)]. Intracellular concentrations of known P-gp and BCRP substrates [(3H)-paclitaxel and (3H)-prazosin, respectively] were significantly higher (indicating less efflux) in NIH-3T3-MDR1 and MDCK-BCRP cells in the presence of 6-OH-BDE-47, but not BDE-47. Collectively, our results indicate that the BDE-47 metabolite 6-OH-BDE-47 is an inhibitor of both P-gp and BCRP efflux activity. These findings suggest that some effects previously attributed to BDE-47 in biological systems may actually be due to 6-OH-BDE-47. Considerations for human exposure are discussed.
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Affiliation(s)
- Satori A Marchitti
- U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, Georgia 30605
| | - Christopher S Mazur
- U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, Georgia 30605
| | - Caleb M Dillingham
- U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, Georgia 30605
| | - Swati Rawat
- U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, Georgia 30605
| | - Anshika Sharma
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602
| | - Jason Zastre
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602
| | - John F Kenneke
- U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, Georgia 30605;
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46
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Maldonado-Rojas W, Rivera-Julio K, Olivero-Verbel J, Aga DS. Mechanisms of interaction between persistent organic pollutants (POPs) and CYP2B6: An in silico approach. CHEMOSPHERE 2016; 159:113-125. [PMID: 27281544 DOI: 10.1016/j.chemosphere.2016.05.049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 04/14/2016] [Accepted: 05/17/2016] [Indexed: 06/06/2023]
Abstract
Human Cytochrome P450s (CYP450) are a group of heme-containing metalloenzymes responsible for recognition and metabolism of numerous xenobiotics, including drugs and environmental contaminants. CYP2B6, a member of CYP450, is well known for being a highly inducible and polymorphic enzyme and for its important role in the oxidative metabolism of environmental pollutants, such as the Polybrominated Diphenyl Ethers (PBDEs) and Polychlorinated Biphenyls (PCBs). However the mechanisms of interaction of PBDEs and PCBs with CYP2B6 is not entirely known. In this work, a computational approach was carried out to study the interactions of 41 POPs (17 PBDEs, 17 PCBs, and 7 Dioxins) with four CYP2B6 protein structures downloaded from PDB data base (PDB: 3UA5, 3QOA, 3QU8 and 4I91) using molecular docking protocols with AutoDock Vina. The best binding affinity values (kcal/mol) were obtained for PBDE-99 (-8.5), PCB-187 (-9.6), and octachloro-dibenzo-dioxin (-9.8) that can be attributed to the hydrophobic interactions with important residues, such as Phe-363, in the catalytic site of CYP2B6. Molecular docking validation revealed the best values for PDB: 3UA5 (R = 0.622, p = 0.001) demonstrating the reliability of molecular docking predictions. The information obtained in this work can be useful in evaluating the modes of interaction of xenobiotic compounds with the catalytic site of CYP2B6 and provide insights on the important role of these enzymes in the metabolism of potentially toxic compounds in humans.
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Affiliation(s)
- Wilson Maldonado-Rojas
- Environmental and Computational Chemistry Group, School of Pharmaceutical Sciences, Zaragocilla Campus, University of Cartagena, 130014 Cartagena, Colombia
| | - Karen Rivera-Julio
- Environmental and Computational Chemistry Group, School of Pharmaceutical Sciences, Zaragocilla Campus, University of Cartagena, 130014 Cartagena, Colombia
| | - Jesus Olivero-Verbel
- Environmental and Computational Chemistry Group, School of Pharmaceutical Sciences, Zaragocilla Campus, University of Cartagena, 130014 Cartagena, Colombia.
| | - Diana S Aga
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
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47
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Chen Y, Ma S, Li Y, Yan M, Zeng G, Zhang J, Zhang J, Tan X. Microbiological study on bioremediation of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) contaminated soil by agricultural waste composting. Appl Microbiol Biotechnol 2016; 100:9709-9718. [DOI: 10.1007/s00253-016-7798-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 06/06/2016] [Accepted: 08/08/2016] [Indexed: 11/30/2022]
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48
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Fu Z, Wang Y, Chen J, Wang Z, Wang X. How PBDEs Are Transformed into Dihydroxylated and Dioxin Metabolites Catalyzed by the Active Center of Cytochrome P450s: A DFT Study. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8155-8163. [PMID: 27363260 DOI: 10.1021/acs.est.6b00524] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Predicting metabolism of chemicals and potential toxicities of relevant metabolites remains a vital and difficult task in risk assessment. Recent findings suggested that polybrominated diphenyl ethers (PBDEs) can be transformed into dihydroxylated and dioxin metabolites catalyzed by cytochrome P450 enzymes (CYPs), whereas the mechanisms pertinent to these transformations remain largely unknown. Here, by means of density functional theory (DFT) calculations, we probed the metabolic pathways of 2,2',4,4'-tetraBDE (BDE-47) using the active center model of CYPs (Compound I). Results show that BDE-47 is first oxidized to monohydroxylated products (HO-BDEs), wherein a keto-enol tautomerism is identified for rearrangement of the cyclohexenone intermediate. Dihydroxylation with HO-BDEs as precursors, has a unique phenolic H-abstraction and hydroxyl rebound pathway that is distinct from that for monohydroxylation, which accounts for the absence of epoxides in in vitro studies. Furthermore, we found only dihydroxylated PBDEs with heterophenyl -OH substituents ortho- and meta- to the ether bond serve as precursors for dioxins, which are evolved from aryl biradical coupling of diketone intermediates that are produced from dehydrogenation of the dihydroxylated PBDEs by Compound I. This study may enlighten the development of computational models that afford mechanism-based prediction of the xenobiotic biotransformation catalyzed by CYPs.
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Affiliation(s)
- Zhiqiang Fu
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology , Dalian 116024, China
| | - Yong Wang
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences , Lanzhou 730000, China
| | - Jingwen Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology , Dalian 116024, China
| | - Zhongyu Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology , Dalian 116024, China
| | - Xingbao Wang
- State Key Laboratory of Fine Chemicals, School of Pharmaceutical Science and Technology, Dalian University of Technology , Dalian 116024, China
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49
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Erratico C, Zheng X, van den Eede N, Tomy G, Covaci A. Stereoselective Metabolism of α-, β-, and γ-Hexabromocyclododecanes (HBCDs) by Human Liver Microsomes and CYP3A4. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8263-8273. [PMID: 27401979 DOI: 10.1021/acs.est.6b01059] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This is the first study investigating the in vitro metabolism of α-, β-, and γ-hexabromocyclododecane (HBCD) stereoisomers in humans and providing semiquantitative metabolism data. Human liver microsomes were incubated with individual racemic mixtures and with individual stereoisomers of α-, β-, and γ-HBCDs, the hydroxylated metabolites formed were analyzed by liquid chromatography-tandem mass spectrometry, and the value of the intrinsic in vitro clearance (Clint,vitro) was calculated. Several mono- and dihydroxylated metabolites of α-, β-, and γ-HBCDs were formed, with mono-OH-HBCDs being the major metabolites. No stereoisomerization of any of the six α-, β-, and γ-HBCD isomers catalyzed by cytochrome P450 (CYP) enzymes occurred. The value of Clint,vitro of α-HBCDs was significantly lower than that of β-HBCDs, which, in turn, was significantly lower than that of γ-HBCDs (p < 0.05). Such differences were explained by the significantly lower values of Clint,vitro of each α-HBCD stereoisomer than those of the β- and γ-HBCD stereoisomers. In addition, significantly lower values of Clint,vitro of the (-) over the (+)α- and β-HBCD stereoisomers, but not γ-HBCDs, were obtained. Our data offer a possible explanation of the enrichment of α-HBCDs over β- and γ-HBCDs on the one hand and, on the other hand, of (-)α-HBCDs over (+)α-HBCDs previously reported in human samples. It also offers information about the mechanism resulting in such enrichments, the stereoisomer-selective metabolism of α-, β-, and γ-HBCDs catalyzed by CYPs with the lack of stereoisomerization.
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Affiliation(s)
- Claudio Erratico
- Toxicological Center, University of Antwerp , Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Xiaobo Zheng
- Toxicological Center, University of Antwerp , Universiteitsplein 1, 2610 Wilrijk, Belgium
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, China
| | - Nele van den Eede
- Toxicological Center, University of Antwerp , Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Gregg Tomy
- Department of Chemistry, University of Manitoba , Winnipeg R3T 2N2, Canada
| | - Adrian Covaci
- Toxicological Center, University of Antwerp , Universiteitsplein 1, 2610 Wilrijk, Belgium
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Díaz-Jaramillo M, Miglioranza KSB, Gonzalez M, Barón E, Monserrat JM, Eljarrat E, Barceló D. Uptake, metabolism and sub-lethal effects of BDE-47 in two estuarine invertebrates with different trophic positions. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 213:608-617. [PMID: 27017137 DOI: 10.1016/j.envpol.2016.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 03/02/2016] [Accepted: 03/02/2016] [Indexed: 06/05/2023]
Abstract
Two microcosm types -sediment-biota and biota-biota- were constructed to simulate different pathways of BDE-47 uptake, metabolism and oxidative stress effects in two key estuarine invertebrates (polychaete Laeonereis acuta and crab Cyrtograpsus angulatus). In the sediment-biota experiment, both species were exposed to spiked sediments; an environmentally reported and a high concentration of BDE-47 for 2 weeks. In the biota-biota experiment, crabs were fed with polychaetes pre-exposed to BDE-47 in the sediment-biota experiment. The sediment-biota experiment first revealed that polychaetes significantly accumulated BDE-47 (biota-sediment accumulation factor >2; p < 0.05) to a much greater extent than the crab organs (muscle, hepatopancreas, gills) at both sediment concentrations. For oxidative stress responses, polychaete and crab tissues exposed to spiked sediment showed a significant increase (p < 0.05) of only glutathione S-transferase (GST) activity with respect to controls in both BDE-47 concentrations. No lipid peroxidation (TBARS) or total antioxidant capacity (ACAP) changes were evident in the species or organs exposed to either BDE-47 sediment concentration. The biota-biota experiment showed that feeding crabs with pre-exposed polychaetes caused BDE-47 accumulation in organs as well as significant amounts of BDE-47 eliminated through feces (p < 0.05). Unlike the sediment-biota exposure, crabs fed with pre-exposed BDE-47 polychaetes showed the most conspicuous oxidative stress responses. Significant changes in GST and ACAP in both hepatopancreas and gills, in addition to enhanced TBARS levels in the hepatopancreas with respect to controls (p < 0.05), revealed that BDE-47 assimilated by invertebrates represents a potential source of toxicity to their predators. No methoxylated metabolites (MeO-PBDEs) were detected during BDE-47 metabolism in the invertebrates in either of the two different exposure types. In contrast, hydroxylated metabolites (OH-PBDEs) were detected in polychaetes and crab organs/feces in both experiments. Our results demonstrate that PBDE hydroxylation is one of the main biotransformation routes of BDE-47 in estuarine animals, which could be associated with the oxidative stress responses found.
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Affiliation(s)
- M Díaz-Jaramillo
- Laboratorio de Ecotoxicología y Contaminación Ambiental, Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad de Mar del Plata-CONICET, Argentina.
| | - K S B Miglioranza
- Laboratorio de Ecotoxicología y Contaminación Ambiental, Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad de Mar del Plata-CONICET, Argentina
| | - M Gonzalez
- Laboratorio de Ecotoxicología y Contaminación Ambiental, Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad de Mar del Plata-CONICET, Argentina
| | - E Barón
- Water and Soil Quality Research Group, Dep. of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain
| | - J M Monserrat
- Universidade Federal do Rio Grande - FURG, Instituto de Ciências Biológicas (ICB), Rio Grande, RS, Brazil
| | - E Eljarrat
- Water and Soil Quality Research Group, Dep. of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain
| | - D Barceló
- Water and Soil Quality Research Group, Dep. of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain
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