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Huang X, Xu K, Lyu L, Ding C, Zhao Y, Wang X. Identification and yield of metabolites of chlorinated paraffins incubated with chicken liver microsomes: Assessment of their potential to convert into metabolites. JOURNAL OF HAZARDOUS MATERIALS 2023; 455:131640. [PMID: 37201278 DOI: 10.1016/j.jhazmat.2023.131640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/11/2023] [Accepted: 05/12/2023] [Indexed: 05/20/2023]
Abstract
Chlorinated paraffins (CPs) are emerging environmental pollutants. Although metabolism has been shown to affect the differential accumulation of short-chain (SCCPs), medium-chain (MCCPs) and long-chain (LCCPs) CPs in birds, CP metabolites have rarely been reported and the extent to which they are formed is still unclear. In this study, single and mixed CP standards were incubated with chicken liver microsomes in vitro to study the generation of CP metabolites. Putative aldehyde/ketone and carboxylic acid metabolites identified by mass spectroscopy data were shown to be false positive results. Phase I metabolism of CPs first formed monohydroxylated ([M-Cl+OH]) and then dihydroxylated ([M-2Cl+2OH]) products. The yields of monohydroxylated metabolites of CPs decreased with increasing carbon chain length and chlorine content at the initial stage of reaction. Notably, the yield of monohydroxylated metabolites of SCCPs with 51.5% Cl content reached 21%, and that of 1,2,5,6,9,10-hexachlorodecane (C10H16Cl6) was as high as 71%. Thus, monohydroxy metabolites of CPs in birds should not be ignored, especially those of SCCPs. This study provides important data that could support improvements to the ecological/health risk assessment of CPs.
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Affiliation(s)
- Xiaomei Huang
- Institute of Quality Standard and Monitoring Technology for Agro-Products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of Quality & Safety Risk Assessment for Agro-Products, Guangzhou 510640, China; Laboratory of Quality & Safety Risk Assessment for Agro-Products (Guangzhou), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
| | - Kaihang Xu
- Institute of Quality Standard and Monitoring Technology for Agro-Products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of Quality & Safety Risk Assessment for Agro-Products, Guangzhou 510640, China; Laboratory of Quality & Safety Risk Assessment for Agro-Products (Guangzhou), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
| | - Lina Lyu
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Chenhong Ding
- Institute of Quality Standard and Monitoring Technology for Agro-Products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Yarong Zhao
- Institute of Quality Standard and Monitoring Technology for Agro-Products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of Quality & Safety Risk Assessment for Agro-Products, Guangzhou 510640, China; Laboratory of Quality & Safety Risk Assessment for Agro-Products (Guangzhou), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
| | - Xu Wang
- Institute of Quality Standard and Monitoring Technology for Agro-Products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of Quality & Safety Risk Assessment for Agro-Products, Guangzhou 510640, China; Laboratory of Quality & Safety Risk Assessment for Agro-Products (Guangzhou), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China.
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2
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Chenchen H, Keqi H, Yanhong Z, Yiye J, Yankuan T, Xiaojun L, Bixian M. In vitro hepatic metabolism of polychlorinated biphenyls with different chlorine-substituted structures in rats and humans: Kinetics, metabolism, and potential nuclear receptor affinities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 864:161043. [PMID: 36549545 DOI: 10.1016/j.scitotenv.2022.161043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 06/17/2023]
Abstract
In this study, the biotransformation behavior and potential nuclear receptor affinities of polychlorinated biphenyls (PCBs) with different chlorine-substituted structures (PCB 77/110/136/174) were explored using human and rat liver microsomes (HLM and RLM). The rate constants (kobs) of PCBs showed the variations in the order patterns for the HLM (PCB 136 > PCB 110 > PCB 174 > PCB 77) and RLM (PCB 110 > PCB 136 > PCB 174 > PCB 77). However, studied PCBs showed similar metabolite profiles and enantioselective of PCBs between HLM and RLM. The Mono-OH-PCBs were the major metabolites of PCB 77/174, whereas mono-OH- and di-OH-PCBs were the major metabolites of PCB 110/136 for the HLM and RLM, indicating that OH-PCBs could be further oxidized. Enantiomeric enrichment of (-)-PCB 136 and (+)-PCB 174 was observed in microsomal metabolism. Moreover, the inflection point of the enantiomer fraction for PCB 136 metabolized by the HLM suggests a competitive metabolism between individual atropisomers. Furthermore, molecular docking results demonstrated the relatively high affinity between PCBs (or OH-PCBs) and certain nuclear receptors, indicating that abnormal metabolic enzyme expression and endocrine disruption occur in PCB-exposed humans.
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Affiliation(s)
- Huang Chenchen
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; China University of Mining & Technology, School of Environmental Science & Spatial Informatics, Xuzhou 221116, Jiangsu, China
| | - Hu Keqi
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-MaCao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Zeng Yanhong
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-MaCao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
| | - Jiang Yiye
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tian Yankuan
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-MaCao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Luo Xiaojun
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-MaCao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Mai Bixian
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
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3
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Teng C, Li Y, Cang T, Xu H, Liu Z, Qi P, Wang Z, Zhao H, Di S, Wang X. Study on the enantioselective bioaccumulation and dissipation of uniconazole enantiomers in earthworm-soil microcosm through supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:29432-29441. [PMID: 36417071 DOI: 10.1007/s11356-022-24023-3] [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: 07/22/2022] [Accepted: 11/01/2022] [Indexed: 06/16/2023]
Abstract
In this work, the enantioselective bioaccumulation and dissipation of uniconazole enantiomers in earthworm-soil microcosm were studied. A fast enantioseparation method of uniconazole through supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) was established. The CHIRALCEL OZ-3 column and a mixture of CO2 and methanol (80:20, v/v) were used within 1.0 min to separate uniconazole enantiomers. The recoveries of uniconazole enantiomers in earthworm and soil samples ranged from 83.3 to 113%, and the intra-day and inter-day relative standard deviation values were lower than 11%. In earthworms, the bioaccumulation concentrations of uniconazole enantiomers increased with time and reached the maximum on the 7th day and then decreased. The elimination of uniconazole enantiomers in earthworms followed the first-order kinetics equation, and the elimination half-lives were approximately 7 days. In artificial soil, the dissipation of uniconazole enantiomers was slow, and the dissipation half-lives were both 25.7 days. No enantioselectivity occurred in the earthworm-soil microcosm. These results may reduce the uncertainty of environmental risk assessment for uniconazole.
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Affiliation(s)
- Chunhong Teng
- College of Agriculture, Northeast Agricultural University, No. 600 Changjiang Road, Harbin, 150030, People's Republic of China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products/Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang, Institute of Quality and Standard of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, People's Republic of China
| | - Ying Li
- College of Agriculture, Northeast Agricultural University, No. 600 Changjiang Road, Harbin, 150030, People's Republic of China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products/Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang, Institute of Quality and Standard of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, People's Republic of China
| | - Tao Cang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products/Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang, Institute of Quality and Standard of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, People's Republic of China
- Agricultural Ministry Key Laboratory for Pesticide Residue Detection, Hangzhou, 310021, People's Republic of China
| | - Hao Xu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products/Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang, Institute of Quality and Standard of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, People's Republic of China
- Agricultural Ministry Key Laboratory for Pesticide Residue Detection, Hangzhou, 310021, People's Republic of China
| | - Zhenzhen Liu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products/Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang, Institute of Quality and Standard of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, People's Republic of China
- Agricultural Ministry Key Laboratory for Pesticide Residue Detection, Hangzhou, 310021, People's Republic of China
| | - Peipei Qi
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products/Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang, Institute of Quality and Standard of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, People's Republic of China
- Agricultural Ministry Key Laboratory for Pesticide Residue Detection, Hangzhou, 310021, People's Republic of China
| | - Zhiwei Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products/Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang, Institute of Quality and Standard of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, People's Republic of China
- Agricultural Ministry Key Laboratory for Pesticide Residue Detection, Hangzhou, 310021, People's Republic of China
| | - Huiyu Zhao
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products/Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang, Institute of Quality and Standard of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, People's Republic of China
- Agricultural Ministry Key Laboratory for Pesticide Residue Detection, Hangzhou, 310021, People's Republic of China
| | - Shanshan Di
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products/Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang, Institute of Quality and Standard of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, People's Republic of China
- Agricultural Ministry Key Laboratory for Pesticide Residue Detection, Hangzhou, 310021, People's Republic of China
| | - Xinquan Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products/Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang, Institute of Quality and Standard of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, People's Republic of China.
- Agricultural Ministry Key Laboratory for Pesticide Residue Detection, Hangzhou, 310021, People's Republic of China.
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Lehmler HJ, Uwimana E, Dean LE, Kovalchuk N, Zhang QY, Ding X. Probing the Role of CYP2 Enzymes in the Atropselective Metabolism of Polychlorinated Biphenyls Using Liver Microsomes from Transgenic Mouse Models. Chem Res Toxicol 2022; 35:2310-2323. [PMID: 36473170 PMCID: PMC9957597 DOI: 10.1021/acs.chemrestox.2c00276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Chiral polychlorinated biphenyls (PCB) are environmentally relevant developmental neurotoxicants. Because their hydroxylated metabolites (OH-PCBs) are also neurotoxic, it is necessary to determine how PCB metabolism affects the developing brain, for example, in mouse models. Because the cytochrome P450 isoforms involved in the metabolism of chiral PCBs remain unexplored, we investigated the metabolism of PCB 91 (2,2',3,4',6-pentachlorobiphenyl), PCB 95 (2,2',3,5',6-pentachlorobiphenyl), PCB 132 (2,2',3,3',4,6'-hexachlorobiphenyl), and PCB 136 (2,2',3,3',6,6'-hexachlorobiphenyl) using liver microsomes from male and female Cyp2a(4/5)bgs-null, Cyp2f2-null, and wild-type mice. Microsomes, pooled by sex, were incubated with 50 μM PCB for 30 min, and the levels and enantiomeric fractions of the OH-PCBs were determined gas chromatographically. All four PCB congeners appear to be atropselectively metabolized by CYP2A(4/5)BGS and CYP2F2 enzymes in a congener- and sex-dependent manner. The OH-PCB metabolite profiles of PCB 91 and PCB 132, PCB congeners with one para-chlorine substituent, differed between null and wild-type mice. No differences in the metabolite profiles were observed for PCB 95 and PCB 136, PCB congeners without a para-chlorine group. These findings suggest that Cyp2a(4/5)bgs-null and Cyp2f2-null mice can be used to study how a loss of a specific metabolic function (e.g., deletion of Cyp2a(4/5)bgs or Cyp2f2) affects the toxicity of chiral PCB congeners.
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Affiliation(s)
- Hans-Joachim Lehmler
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242, United States
| | - Eric Uwimana
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242, United States
| | - Laura E. Dean
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242, United States
| | - Nataliia Kovalchuk
- Department of Pharmacology & Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, United States
| | - Qing-Yu Zhang
- Department of Pharmacology & Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, United States
| | - Xinxin Ding
- Department of Pharmacology & Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, United States
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Ito T, Miwa C, Haga Y, Kubo M, Itoh T, Yamamoto K, Mise S, Goto E, Tsuzuki H, Matsumura C, Nakano T, Inui H. Enantioselective metabolism of chiral polychlorinated biphenyl 2,2',3,4,4',5',6-Heptachlorobiphenyl (CB183) by human and rat CYP2B subfamilies. CHEMOSPHERE 2022; 308:136349. [PMID: 36084836 DOI: 10.1016/j.chemosphere.2022.136349] [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: 02/27/2022] [Revised: 08/10/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
Chiral polychlorinated biphenyls (PCBs) have atropisomers that have different axial chiralities and exist as racemic mixtures. However, biochemical processes often result in the unequal accumulation of these atropisomers in organisms. This phenomenon leads to enantiospecific toxicity enhancement or reduction because either of the atropisomers mainly affects toxicity expression. Enantioselective accumulation is caused by cytochrome P450 (CYP, P450) monooxygenases, especially the CYP2B subfamilies. Therefore, this study investigates the metabolism of a chiral PCB in vitro. Both atropisomers isolated from racemic 2,2',3,4,4',5',6-heptachlorobiphenyl (CB183) were metabolized by human CYP2B6, but not rat CYP2B1. This may be due to the difference in the size of the substrate-binding cavities of CYP2B6 and CYP2B1. The stable accommodation of (-)-CB183 in the cavity without any steric hindrance explained the preferential metabolism of (-)-CB183 compared to (+)-CB183. Two hydroxylated metabolites, 3'-OH-CB183 and 5-OH-CB183, were identified. The docking study showed that the 3'-position of the trichlorophenyl ring closely approaches the heme of CYP2B6. To our knowledge, this is the first study to elucidate the structural basis of chiral PCB metabolism by P450 isozymes. These results will help promote the precise toxicity evaluation of chiral PCBs and provide an explanation of the structural basis of chiral PCB metabolism.
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Affiliation(s)
- Terushi Ito
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Chiharu Miwa
- Faculty of Agriculture, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Yuki Haga
- Hyogo Prefectural Institute of Environmental Sciences, 3-1-18 Yukihiracho, Suma-ku, Kobe, Hyogo, 654-0037, Japan
| | - Makoto Kubo
- Laboratory of Drug Design and Medicinal Chemistry, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo, 194-8543, Japan
| | - Toshimasa Itoh
- Laboratory of Drug Design and Medicinal Chemistry, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo, 194-8543, Japan
| | - Keiko Yamamoto
- Laboratory of Drug Design and Medicinal Chemistry, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo, 194-8543, Japan
| | - Shintaro Mise
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Erika Goto
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Harunobu Tsuzuki
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Chisato Matsumura
- Hyogo Prefectural Institute of Environmental Sciences, 3-1-18 Yukihiracho, Suma-ku, Kobe, Hyogo, 654-0037, Japan
| | - Takeshi Nakano
- Research Center for Environmental Preservation, Osaka University, 2-4 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hideyuki Inui
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan; Biosignal Research Center, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan.
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Xue P, Liu X, Jia H, Yuan H, Liu B, Zhang J, He Z. Environmental behavior of the chiral fungicide epoxiconazole in earthworm-soil system: Enantioselective enrichment, degradation kinetics, chiral metabolite identification, and biotransformation mechanism. ENVIRONMENT INTERNATIONAL 2022; 167:107442. [PMID: 35921772 DOI: 10.1016/j.envint.2022.107442] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 07/21/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
The environmental impact of the chiral fungicide epoxiconazole and its chiral transformation products (TPs) on non-target organisms and the environment has become a significant concern due to its widespread use in agricultural practice. Enantioselectivity studies of parent contaminants cannot adequately assess the complexity of its chiral TPs in the environment. This study aimed to investigate the environmental behavior of epoxiconazole in an earthworm-soil system. 2S,3R-(-)-epoxiconazole was preferentially enriched in earthworms during the accumulation phase (p < 0.05), but no enantioselectivity was observed during the elimination phase. One methoxylated and four hydroxylated chiral TPs were identified in soil, earthworm, and excrement. The epoxy ring hydroxylated TP and methoxylated TP of epoxiconazole were discovered for the first time in the environment. The chemically specific enantioselectivity with enantiomer fraction (EF) > 0.8 was observed for the TPs in different matrices. The CYP450 monooxygenase of earthworm was significant activated. In vitro enzyme metabolism experiments (earthworm microsomes and recombinant CYP450 enzymes CYP2A6, CYP 2C9, and CYP 3A4) were carried out to further explain the biotransformation mechanism of epoxiconazole in earthworm. This study provides new evidence of enantiomeric biotransformation of chiral fungicide epoxiconazole in the earthworm-soil system and could provide valuable insights into their environmental risk assessment.
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Affiliation(s)
- Pengfei Xue
- Key Laboratory for Environmental Factors Control of Agro-product Quality Safety, Ministry of Agriculture and Rural Affairs, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, PR China
| | - Xiaowei Liu
- Key Laboratory for Environmental Factors Control of Agro-product Quality Safety, Ministry of Agriculture and Rural Affairs, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, PR China
| | - Hao Jia
- Key Laboratory for Environmental Factors Control of Agro-product Quality Safety, Ministry of Agriculture and Rural Affairs, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, PR China
| | - Haiyue Yuan
- Key Laboratory for Environmental Factors Control of Agro-product Quality Safety, Ministry of Agriculture and Rural Affairs, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, PR China
| | - Bingjie Liu
- SCIEX, Analytical Instrument Trading Co. Ltd., Beijing 100015, PR China
| | - Jingran Zhang
- SCIEX, Analytical Instrument Trading Co. Ltd., Beijing 100015, PR China
| | - Zeying He
- Key Laboratory for Environmental Factors Control of Agro-product Quality Safety, Ministry of Agriculture and Rural Affairs, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, PR China.
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Inui H, Ito T, Miwa C, Haga Y, Kubo M, Itoh T, Yamamoto K, Miyaoka M, Mori T, Tsuzuki H, Mise S, Goto E, Matsumura C, Nakano T. Differences in Enantioselective Hydroxylation of 2,2',3,6-Tetrachlorobiphenyl (CB45) and 2,2',3,4',6-Pentachlorobiphenyl (CB91) by Human and Rat CYP2B Subfamilies. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:10204-10215. [PMID: 35801261 DOI: 10.1021/acs.est.2c01155] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Although polychlorinated biphenyls (PCBs) were commercially banned half a century ago, contamination of the environment and organisms by PCBs is still observed. PCBs show high persistence and bioaccumulation, resulting in toxicity. Among PCBs, chiral PCBs with more than three chlorine atoms at the ortho-position exhibit developmental and neurodevelopmental toxicity. Because toxicity is dependent on the atropisomer, atropisomer-specific metabolism is vital in determining toxicity. However, structural information on enantioselective metabolism remains elusive. Cytochrome P450 (CYP, P450) monooxygenases, particularly human CYP2B6 and rat CYP2B1, metabolize separated atropisomers of 2,2',3,6-tetrachlorobiphenyl (CB45) and 2,2',3,4',6-pentachlorobiphenyl (CB91) to dechlorinated and hydroxylated metabolites. Docking studies using human CYP2B6 predict 4'-hydroxy (OH)-CB45 from (aR)-CB45 as a major metabolite of CB45. Di-OH- and dechlorinated OH-metabolites from human CYP2B6 and rat CYP2B1 are also detected. Several hydroxylated metabolites are derived from CB91 by both P450s; 5-OH-CB91 is predicted as a major metabolite. CB91 dechlorination is also detected by identifying 3-OH-CB51. A stable conformation of PCBs in the substrate-binding cavity and close distance to P450 heme are responsible for high metabolizing activities. As hydroxylation and dechlorination change PCB toxicity, this approach helps understand the possible toxicity of chiral PCBs in mammals.
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Affiliation(s)
- Hideyuki Inui
- Biosignal Research Center, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo 657-8501, Japan
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo 657-8501, Japan
| | - Terushi Ito
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo 657-8501, Japan
| | - Chiharu Miwa
- Faculty of Agriculture, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo 657-8501, Japan
| | - Yuki Haga
- Hyogo Prefectural Institute of Environmental Sciences, 3-1-18 Yukihiracho, Suma-ku, Kobe, Hyogo 654-0037, Japan
| | - Makoto Kubo
- Laboratory of Drug Design and Medicinal Chemistry, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
| | - Toshimasa Itoh
- Laboratory of Drug Design and Medicinal Chemistry, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
| | - Keiko Yamamoto
- Laboratory of Drug Design and Medicinal Chemistry, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
| | - Masayuki Miyaoka
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tadashi Mori
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Harunobu Tsuzuki
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo 657-8501, Japan
| | - Shintaro Mise
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo 657-8501, Japan
| | - Erika Goto
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo 657-8501, Japan
| | - Chisato Matsumura
- Hyogo Prefectural Institute of Environmental Sciences, 3-1-18 Yukihiracho, Suma-ku, Kobe, Hyogo 654-0037, Japan
| | - Takeshi Nakano
- Research Center for Environmental Preservation, Osaka University, 2-4 Yamadaoka, Suita, Osaka 565-0871, Japan
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8
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Huang X, Cui Z, Ding C, Su Q, Lin X, Wang W, Yin Q, Wang X. Differential Accumulation of Short-, Medium-, and Long-Chain Chlorinated Paraffin in Free-Range Laying Hens from an E-Waste Recycling Area. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:10329-10337. [PMID: 34449201 DOI: 10.1021/acs.jafc.1c04546] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Chlorinated paraffins (CPs) are environmental pollutants of emerging concern. Long-chain CPs (LCCPs) are considered of lesser concern than other CPs in food due to their lower accumulation in most organisms. However, LCCPs have been shown to accumulate preferentially in birds. We used ultrahigh-performance liquid chromatography combined with electrospray ionization Orbitrap mass spectrometry (UPLC-ESI-Orbitrap MS) to analyze CPs (C10-26Cl4-12) in tissues of free-range hens, their feed, and local soils. Feed was found to be the main source of CP intake. The CP carbon chain length had little impact on their absorption. C18-CPs were excreted in preference to C13-CPs by laying. The metabolic elimination rates of CPs (0.2 μg/mL) estimated using chicken liver microsomes were in the order C12Cl6 (91%) > C12Cl8 (57%) > C18Cl6 (12%) > C18Cl8 (6%). CPs with longer carbon chains accumulated preferentially in muscle and adipose tissues, and the accumulation of specific carbon chain lengths was related to the content and composition of different CPs in the intake source.
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Affiliation(s)
- Xiaomei Huang
- Institute of Quality Standard and Monitoring Technology for Agro-products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
- Guangdong Provincial Key Laboratory of Quality & Safety Risk Assessment for Agro-products, Guangzhou 510640, China
| | - Zefeng Cui
- Institute of Quality Standard and Monitoring Technology for Agro-products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Chenhong Ding
- Institute of Quality Standard and Monitoring Technology for Agro-products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Qiuquan Su
- Institute of Quality Standard and Monitoring Technology for Agro-products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Xuexian Lin
- Guangdong Agricultural Science and Technology Monitoring Technology Co., Ltd, Guangzhou 510640, China
| | - Weili Wang
- Institute of Quality Standard and Monitoring Technology for Agro-products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Qiumiao Yin
- Institute of Quality Standard and Monitoring Technology for Agro-products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
- Guangdong Provincial Key Laboratory of Quality & Safety Risk Assessment for Agro-products, Guangzhou 510640, China
| | - Xu Wang
- Institute of Quality Standard and Monitoring Technology for Agro-products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
- Guangdong Provincial Key Laboratory of Quality & Safety Risk Assessment for Agro-products, Guangzhou 510640, China
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9
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Zhang CY, Flor S, Ruiz P, Ludewig G, Lehmler HJ. Characterization of the Metabolic Pathways of 4-Chlorobiphenyl (PCB3) in HepG2 Cells Using the Metabolite Profiles of Its Hydroxylated Metabolites. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:9052-9062. [PMID: 34125531 PMCID: PMC8264946 DOI: 10.1021/acs.est.1c01076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The characterization of the metabolism of lower chlorinated PCB, such as 4-chlorobiphenyl (PCB3), is challenging because of the complex metabolite mixtures formed in vitro and in vivo. We performed parallel metabolism studies with PCB3 and its hydroxylated metabolites to characterize the metabolism of PCB3 in HepG2 cells using nontarget high-resolution mass spectrometry (Nt-HRMS). Briefly, HepG2 cells were exposed for 24 h to 10 μM PCB3 or its seven hydroxylated metabolites in DMSO or DMSO alone. Six classes of metabolites were identified with Nt-HRMS in the culture medium exposed to PCB3, including monosubstituted metabolites at the 3'-, 4'-, 3-, and 4- (1,2-shift product) positions and disubstituted metabolites at the 3',4'-position. 3',4'-Di-OH-3 (4'-chloro-3,4-dihydroxybiphenyl), which can be oxidized to a reactive and toxic PCB3 quinone, was a central metabolite that was rapidly methylated. The resulting hydroxylated-methoxylated metabolites underwent further sulfation and, to a lesser extent, glucuronidation. Metabolomic analyses revealed an altered tryptophan metabolism in HepG2 cells following PCB3 exposure. Some PCB3 metabolites were associated with alterations of endogenous metabolic pathways, including amino acid metabolism, vitamin A (retinol) metabolism, and bile acid biosynthesis. In-depth studies are needed to investigate the toxicities of PCB3 metabolites, especially the 3',4'-di-OH-3 derivatives identified in this study.
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Affiliation(s)
- Chun-Yun Zhang
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Susanne Flor
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Patricia Ruiz
- Office
of Innovation and Analytics, Simulation Science Section, Agency for Toxic Substances and Disease Registry, Atlanta, Georgia 30333, United States
| | - Gabriele Ludewig
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Hans-Joachim Lehmler
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
- . Tel.: (319) 335-4981. Fax: (319) 335-4290
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10
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Zhan T, Zhang L, Cui S, Liu W, Zhou R, Zhuang S. Dioxybenzone triggers enhanced estrogenic effect via metabolic activation: in silico, in vitro and in vivo investigation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115766. [PMID: 33039677 DOI: 10.1016/j.envpol.2020.115766] [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: 07/01/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 06/11/2023]
Abstract
Dioxybenzone is widely used in cosmetics and personal care products and frequently detected in multiple environmental media and human samples. However, the current understanding of the metabolic susceptibility of dioxybenzone and the potential endocrine disruption through its metabolites in mimicking human estrogens remains largely unclear. Here we investigated the in vitro metabolism of dioxybenzone, detected the residue of metabolites in rats, and determined the estrogenic disrupting effects of these metabolites toward estrogen receptor α (ERα). In vitro metabolism revealed two major metabolites from dioxybenzone, i.e., M1 through the demethylation of methoxy moiety and M2 through hydroxylation of aromatic carbon. M1 and M2 were both rapidly detected in rat plasma upon exposure to dioxybenzone, which were then distributed into organs of rats in the order of livers > kidneys > uteri > ovaries. The 100 ns molecular dynamics simulation revealed that M1 and M2 formed hydrogen bond to residue Leu387 and Glu353, respectively, on ERα ligand binding domain, leading to a reduced binding free energy. M1 and M2 also significantly induced estrogenic effect in comparison to dioxybenzone as validated by the recombinant ERα yeast two-hybrid assay and uterotrophic assay. Overall, our study revealed the potential of metabolic activation of dioxybenzone to induce estrogenic disrupting effects, suggesting the need for incorporating metabolic evaluation into the health risk assessment of benzophenones and their structurally similar analogs.
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Affiliation(s)
- Tingjie Zhan
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 310058, Hangzhou, China
| | - Leili Zhang
- Computational Biological Center, IBM Thomas J. Watson Research Center, Yorktown Heights, NY, United States
| | - Shixuan Cui
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 310058, Hangzhou, China
| | - Weiping Liu
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 310058, Hangzhou, China
| | - Ruhong Zhou
- Institute of Quantitative Biology and College of Life Sciences, Zhejiang University, 310058, Hangzhou, China; Department of Chemistry, Columbia University, New York, NY, United States
| | - Shulin Zhuang
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 310058, Hangzhou, China.
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11
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Idda T, Bonas C, Hoffmann J, Bertram J, Quinete N, Schettgen T, Fietkau K, Esser A, Stope MB, Leijs MM, Baron JM, Kraus T, Voigt A, Ziegler P. Metabolic activation and toxicological evaluation of polychlorinated biphenyls in Drosophila melanogaster. Sci Rep 2020; 10:21587. [PMID: 33299007 PMCID: PMC7726022 DOI: 10.1038/s41598-020-78405-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 11/20/2020] [Indexed: 01/26/2023] Open
Abstract
Degradation of polychlorinated biphenyls (PCBs) is initiated by cytochrome P450 (CYP) enzymes and includes PCB oxidation to OH-metabolites, which often display a higher toxicity than their parental compounds. In search of an animal model reflecting PCB metabolism and toxicity, we tested Drosophila melanogaster, a well-known model system for genetics and human disease. Feeding Drosophila with lower chlorinated (LC) PCB congeners 28, 52 or 101 resulted in the detection of a human-like pattern of respective OH-metabolites in fly lysates. Feeding flies high PCB 28 concentrations caused lethality. Thus we silenced selected CYPs via RNA interference and analyzed the effect on PCB 28-derived metabolite formation by assaying 3-OH-2',4,4'-trichlorobiphenyl (3-OHCB 28) and 3'-OH-4',4,6'-trichlorobiphenyl (3'-OHCB 28) in fly lysates. We identified several drosophila CYPs (dCYPs) whose knockdown reduced PCB 28-derived OH-metabolites and suppressed PCB 28 induced lethality including dCYP1A2. Following in vitro analysis using a liver-like CYP-cocktail, containing human orthologues of dCYP1A2, we confirm human CYP1A2 as a PCB 28 metabolizing enzyme. PCB 28-induced mortality in flies was accompanied by locomotor impairment, a common phenotype of neurodegenerative disorders. Along this line, we show PCB 28-initiated caspase activation in differentiated fly neurons. This suggested the loss of neurons through apoptosis. Our findings in flies are congruent with observation in human exposed to high PCB levels. In plasma samples of PCB exposed humans, levels of the neurofilament light chain increase after LC-PCB exposure, indicating neuronal damage. In summary our findings demonstrate parallels between Drosophila and the human systems with respect to CYP mediated metabolism and PCB mediated neurotoxicity.
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Affiliation(s)
- T Idda
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | - C Bonas
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | - J Hoffmann
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | - J Bertram
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | - N Quinete
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
- Department of Chemistry and Biochemistry, Florida International University Florida, Florida, USA
| | - T Schettgen
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | - K Fietkau
- Department of Dermatology and Allergology, RWTH Aachen University, 52074, Aachen, Germany
| | - A Esser
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | - M B Stope
- Department of Gynecology and Gynecological Oncology, University Hospital Bonn, Bonn, Germany
| | - M M Leijs
- Department of Dermatology and Allergology, RWTH Aachen University, 52074, Aachen, Germany
| | - J M Baron
- Department of Dermatology and Allergology, RWTH Aachen University, 52074, Aachen, Germany
| | - T Kraus
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | - A Voigt
- Department of Neurology, University Medical Center, RWTH Aachen University, 52074, Aachen, Germany
- JARA-BRAIN Institute Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich GmbH, RWTH Aachen University, 52074, Aachen, Germany
| | - P Ziegler
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany.
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12
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Zhang CY, Flor S, Ludewig G, Lehmler HJ. Atropselective Partitioning of Polychlorinated Biphenyls in a HepG2 Cell Culture System: Experimental and Modeling Results. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:13817-13827. [PMID: 33059451 PMCID: PMC7642102 DOI: 10.1021/acs.est.0c02508] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Cell culture models are used to study the toxicity of polychlorinated biphenyls (PCBs); however, it is typically unknown how much PCB enters the cells and, for chiral PCBs, if the partitioning is atropselective. We investigated the partitioning of racemic PCB 91, PCB 95, PCB 132, and PCB 136 in HepG2 cells following a 72 h incubation. PCBs were present in the cell culture medium (60.7-88.8%), cells (8.0-14.6%), and dishes (2.3-7.8%) and displayed atropisomeric enrichment in the cells (enantiomeric fraction [EF] = 0.55-0.77) and dishes (EF = 0.53-0.68). Polyparameter linear free energy relationships coupled with a composition-based model provided a good estimate of the PCB levels in the cells and cell culture medium. The free concentration was subsequently used to extrapolate from the nominal cell culture concentration to PCB tissue levels and vice versa. This approach can be used for in vitro-in vivo extrapolations for all 209 PCB congeners. However, this model (and modified models based on descriptors incorporating atropselective interactions, i.e., relative retention times on chiral columns) did not predict the atropselective partitioning in the cell culture system. Improved chemical descriptors that account for the atropselective binding of PCBs to biological macromolecules are, therefore, needed to predict the atropselective partitioning of PCBs in biological systems.
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Affiliation(s)
- Chun-Yun Zhang
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Susanne Flor
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Gabriele Ludewig
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
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13
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Polychlorinated Biphenyls (PCBs): Risk Factors for Autism Spectrum Disorder? TOXICS 2020; 8:toxics8030070. [PMID: 32957475 PMCID: PMC7560399 DOI: 10.3390/toxics8030070] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/14/2020] [Accepted: 09/16/2020] [Indexed: 02/06/2023]
Abstract
Autism spectrum disorder (ASD) includes a group of multifactorial neurodevelopmental disorders defined clinically by core deficits in social reciprocity and communication, restrictive interests and repetitive behaviors. ASD affects one in 54 children in the United States, one in 89 children in Europe, and one in 277 children in Asia, with an estimated worldwide prevalence of 1-2%. While there is increasing consensus that ASD results from complex gene x environment interactions, the identity of specific environmental risk factors and the mechanisms by which environmental and genetic factors interact to determine individual risk remain critical gaps in our understanding of ASD etiology. Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants that have been linked to altered neurodevelopment in humans. Preclinical studies demonstrate that PCBs modulate signaling pathways implicated in ASD and phenocopy the effects of ASD risk genes on critical morphometric determinants of neuronal connectivity, such as dendritic arborization. Here, we review human and experimental evidence identifying PCBs as potential risk factors for ASD and discuss the potential for PCBs to influence not only core symptoms of ASD, but also comorbidities commonly associated with ASD, via effects on the central and peripheral nervous systems, and/or peripheral target tissues, using bladder dysfunction as an example. We also discuss critical data gaps in the literature implicating PCBs as ASD risk factors. Unlike genetic factors, which are currently irreversible, environmental factors are modifiable risks. Therefore, data confirming PCBs as risk factors for ASD may suggest rational approaches for the primary prevention of ASD in genetically susceptible individuals.
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14
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Liu J, Tan Y, Song E, Song Y. A Critical Review of Polychlorinated Biphenyls Metabolism, Metabolites, and Their Correlation with Oxidative Stress. Chem Res Toxicol 2020; 33:2022-2042. [DOI: 10.1021/acs.chemrestox.0c00078] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Jing Liu
- College of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang 550025, People’s Republic of China
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People’s Republic of China
| | - Ya Tan
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People’s Republic of China
| | - Erqun Song
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People’s Republic of China
| | - Yang Song
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, People’s Republic of China
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15
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Hu K, Yu H, Li Z, Jin G, Jia H, Song M, Liu Y. Human CYP2E1-activated mutagenicity of dioxin-like PCBs 105 and 118-Experimental data consistent with molecular docking results. Toxicology 2020; 437:152438. [PMID: 32199159 DOI: 10.1016/j.tox.2020.152438] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/05/2020] [Accepted: 03/12/2020] [Indexed: 02/07/2023]
Abstract
Polychlorinated biphenyls (PCBs) are persistent organic pollutants with human carcinogenicity. Many lower chlorinated and non-dioxin-like PCBs have been observed to be mutagenic following activation by human CYP2E1, while activation of dioxin-like (DL-) PCBs by this enzyme has never been evidenced. In this study, each DL-PCB was analyzed by molecular docking to human CYP2E1 protein for predicting a substrate interaction. All compounds demonstrated high affinities with the active site of human CYP2E1, binding energy being -8.7 ∼ -9.7 kcal/mol. However, most compounds demonstrated ligand-heme distances as ≥ 6.8 Å, while the values for 2,3,3',4,4'- (PCB 105) and 2,3',4,4',5-pentachlorobiphenyl (PCB 118) were 5.3 and 5.4 Å, respectively (valid for electron transfer). Experimentally, both PCB 105 and 118 induced micronuclei in a V79-derived cell line engineered for expression of human CYP2E1 at low micromolar concentrations, while inactive or weakly positive in V79-Mz control cells; these effects were blocked or reduced by 1-aminobenzotriazole, a suicide CYP inhibitor. However, DL-PCBs 77, 81 and 126 were all negative in both cell lines. In a human hepatoma (C3A) cell line, PCB 105 and 118 induced micronuclei marginally, while with ethanol pretreatment (to stabilize CYP2E1) both compounds induced micronuclei efficiently, and co-exposure to trans-1,2-dichloroethylene (a selective CYP2E1 inhibitor) led to clearly negative results with both compounds. Finally, both PCB 105 and 118 induced PIG-A gene mutations in C3A cells, which was blocked by trans-1,2-dichloroethylene. In summary, in silico and experimental results consistently suggest that DL- PCBs 105 and 118 may be activated by human CYP2E1 for mutagenic activities.
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Affiliation(s)
- Keqi Hu
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, Guangzhou, 510515, China
| | - Hang Yu
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, Guangzhou, 510515, China
| | - Zihuan Li
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, Guangzhou, 510515, China
| | - Guifang Jin
- Department of Pharmacology, School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou, 510006, China
| | - Hansi Jia
- The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, Guangdong, 518033, China
| | - Meiqi Song
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, Guangzhou, 510515, China
| | - Yungang Liu
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, Guangzhou, 510515, China.
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16
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Chen Y, Wu Y, Xiao W, Jia H, Glatt H, Shi M, Liu Y. Human CYP1B1-dependent genotoxicity of dioxin-like polychlorinated biphenyls in mammalian cells. Toxicology 2020; 429:152329. [DOI: 10.1016/j.tox.2019.152329] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/12/2019] [Accepted: 11/12/2019] [Indexed: 01/18/2023]
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17
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Uwimana E, Cagle B, Yeung C, Li X, Patterson EV, Doorn JA, Lehmler HJ. Atropselective Oxidation of 2,2',3,3',4,6'-Hexachlorobiphenyl (PCB 132) to Hydroxylated Metabolites by Human Liver Microsomes and Its Implications for PCB 132 Neurotoxicity. Toxicol Sci 2019; 171:406-420. [PMID: 31268529 PMCID: PMC6760323 DOI: 10.1093/toxsci/kfz150] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 06/18/2019] [Accepted: 06/18/2019] [Indexed: 02/05/2023] Open
Abstract
Polychlorinated biphenyls (PCBs) have been associated with neurodevelopmental disorders. Several neurotoxic congeners display axial chirality and atropselectively affect cellular targets implicated in PCB neurotoxicity. Only limited information is available regarding the atropselective metabolism of these congeners in humans and their atropselective effects on neurotoxic outcomes. Here we investigate the hypothesis that the oxidation of 2,2',3,3',4,6'-hexachlorobiphenyl (PCB 132) by human liver microsomes (HLMs) and their effects on dopaminergic cells in culture are atropselective. Racemic PCB 132 was incubated with pooled or single donor HLMs, and levels and enantiomeric fractions of PCB 132 and its metabolites were determined gas chromatographically. The major metabolite was either 2,2',3,4,4',6'-hexachlorobiphenyl-3'-ol (3'-140), a 1,2-shift product, or 2,2',3,3',4,6'-hexachlorobiphenyl-5'-ol (5'-132). The PCB 132 metabolite profiles displayed inter-individual differences and depended on the PCB 132 atropisomer. Computational studies suggested that 3'-140 is formed via a 3,4-arene oxide intermediate. The second eluting atropisomer of PCB 132, first eluting atropisomer of 3'-140, and second eluting atropisomer of 5'-132 were enriched in all HLM incubations. Enantiomeric fractions of the PCB 132 metabolites differed only slightly between the single donor HLM preparations investigated. Reactive oxygen species and levels of dopamine and its metabolites were not significantly altered after a 24 h exposure of dopaminergic cells to pure PCB 132 atropisomers. These findings suggest that there are inter-individual differences in the atropselective biotransformation of PCB 132 to its metabolites in humans; however, the resulting atropisomeric enrichment of PCB 132 is unlikely to affect neurotoxic outcomes associated with the endpoints investigated in the study.
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Affiliation(s)
- Eric Uwimana
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa
| | - Brianna Cagle
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, IA, United States
| | - Coby Yeung
- Department of Chemistry, College of Arts and Sciences, Stony Brook University, Stony Brook, New York
| | - Xueshu Li
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa
| | - Eric V Patterson
- Department of Chemistry, College of Arts and Sciences, Stony Brook University, Stony Brook, New York
| | - Jonathan A Doorn
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, IA, United States
| | - Hans-Joachim Lehmler
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa
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18
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Uwimana E, Ruiz P, Li X, Lehmler HJ. Human CYP2A6, CYP2B6, AND CYP2E1 Atropselectively Metabolize Polychlorinated Biphenyls to Hydroxylated Metabolites. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:2114-2123. [PMID: 30576102 PMCID: PMC6380921 DOI: 10.1021/acs.est.8b05250] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Exposure to chiral polychlorinated biphenyls (PCBs) has been associated with neurodevelopmental disorders. Their hydroxylated metabolites (OH-PCBs) are also potentially toxic to the developing human brain; however, the formation of OH-PCBs by human cytochrome P450 (P450) isoforms is poorly investigated. To address this knowledge gap, we investigated the atropselective biotransformation of 2,2',3,4',6-pentachlorobiphenyl (PCB 91), 2,2',3,5',6-pentachlorobiphenyl (PCB 95), 2,2',3,3',4,6'-hexachlorobiphenyl (PCB 132), and 2,2',3,3',6,6'-hexachlorobiphenyl (PCB 136) by different human P450 isoforms. In silico predictions with ADMET Predictor and MetaDrug software suggested a role of CYP1A2, CYP2A6, CYP2B6, CYP2E1, and CYP3A4 in the metabolism of chiral PCBs. Metabolism studies with recombinant human enzymes demonstrated that CYP2A6 and CYP2B6 oxidized PCB 91 and PCB 132 in the meta position and that CYP2A6 oxidized PCB 95 and PCB 136 in the para position. CYP2B6 played only a minor role in the metabolism of PCB 95 and PCB 136 and formed meta-hydroxylated metabolites. Traces of para-hydroxylated PCB metabolites were detected in incubations with CYP2E1. No hydroxylated metabolites were present in incubations with CYP1A2 or CYP3A4. Atropselective analysis revealed P450 isoform-dependent and congener-specific atropselective enrichment of OH-PCB metabolites. These findings suggest that CYP2A6 and CYP2B6 play an important role in the oxidation of neurotoxic PCBs to chiral OH-PCBs in humans.
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Affiliation(s)
- Eric Uwimana
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242, United States
| | - Patricia Ruiz
- Division of Toxicology and Human Health Sciences, Computational Toxicology and Methods Development Lab, Agency for Toxic Substances and Disease Registry, Atlanta, GA 30333, United States
| | - Xueshu Li
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242, United States
| | - Hans-Joachim Lehmler
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242, United States
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19
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Kaifie A, Schettgen T, Gube M, Ziegler P, Kraus T, Esser A. Functional and structural liver abnormalities in former PCB exposed workers - analyses from the HELPcB cohort. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2018; 82:52-61. [PMID: 30526399 DOI: 10.1080/15287394.2018.1555728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The effects of polychlorinated biphenyls (PCB) on liver function and structure are still under debate. Although higher transaminase activity and tumor promoting potential of PCB reported for animal and human studies was suggested, these studies were not able to provide definitive evidence on the ability of these chemicals to affect liver function and contribution to tumor development. The aim of this study was to determine the influence of PCB on liver function and morphology in a cohort of former PCB exposed workers. Over 5 years, a longitudinal analysis of the association between PCB concentration and hepatic transaminases such as alanine transaminase (ALT) aspartate amino transaminase (AST) and gamma glutamyltransferase (γGT), as well as liver size and structure was undertaken. Data demonstrated a significant inverse association between PCB concentration and γGT activity levels but there was no marked relationship with AST and ALT activities. Regarding sonographic examination, a significant association was found between liver size and PCB concentration. This association remained, even after adjusting for alcohol consumption, liver affecting drugs, timespan of internal exposure, or age. No marked correlation was noted between PCB concentration and liver structure changes. In summary, an association was observed between PCB concentration and γGT activity levels as well as liver size in humans. The long-term health consequences attributed to PCB on liver and in particular in tumorigenesis are not foreseeable in our cohort thus far, but remain a focus in further ongoing surveillance.
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Affiliation(s)
- Andrea Kaifie
- a Institute of Occupational, Social, and Environmental Medicine, Medical Faculty , RWTH Aachen University , Aachen , Germany
| | - Thomas Schettgen
- a Institute of Occupational, Social, and Environmental Medicine, Medical Faculty , RWTH Aachen University , Aachen , Germany
| | - Monika Gube
- a Institute of Occupational, Social, and Environmental Medicine, Medical Faculty , RWTH Aachen University , Aachen , Germany
- b Public Health Department Aachen , Aachen , Aachen , Germany
| | - Patrick Ziegler
- a Institute of Occupational, Social, and Environmental Medicine, Medical Faculty , RWTH Aachen University , Aachen , Germany
| | - Thomas Kraus
- a Institute of Occupational, Social, and Environmental Medicine, Medical Faculty , RWTH Aachen University , Aachen , Germany
| | - André Esser
- a Institute of Occupational, Social, and Environmental Medicine, Medical Faculty , RWTH Aachen University , Aachen , Germany
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20
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Vasko T, Hoffmann J, Gostek S, Schettgen T, Quinete N, Preisinger C, Kraus T, Ziegler P. Telomerase gene expression bioassays indicate metabolic activation of genotoxic lower chlorinated polychlorinated biphenyls. Sci Rep 2018; 8:16903. [PMID: 30443001 PMCID: PMC6237825 DOI: 10.1038/s41598-018-35043-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 10/29/2018] [Indexed: 12/18/2022] Open
Abstract
Polychlorinated biphenyls (PCBs) are ubiquitously occurring pollutants with different chemical and toxicological properties. In this study we evaluated blood plasma samples of two PCB-exposed cohorts for their ability to alter telomerase (hTERT) gene expression. Blood plasma from PCB-exposed individuals inhibited hTERT expression depending solely on the concentration of lower chlorinated PCBs, with the lowest observed adverse effect level (LOAEL) at a plasma concentration between 0.5 and 2 µg/L of LC PCBs. Individual OH-metabolites derived from the WHO indicator congeners PCB 28 and PCB 101 mimicked these effects on hTERT expression in vitro with high toxicity, including DNA damage. However, by the combination of different OH-metabolites, the bio effective PCB concentration was reduced and the respective effects on hTERT expression could be increased. At a concentration which showed no toxic activity in MTT assay, hTERT inhibition reflected the interference of OH-PCBs with the mitochondrial respiratory chain, which could lead to the production of reactive oxygen species (ROS). As individual OH-metabolites already showed a much stronger inhibition of hTERT gene expression at a lower concentration than their parental compounds, the hTERT gene expression bioassay described in this study seems to indicate metabolic activation of LC PCBs rather than the mere effect of LC PCBs on their own. In summary, this study provides dose-response linkages between effects of lower chlorinated PCBs and their concentrations in human plasma.
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Affiliation(s)
- Theresa Vasko
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | - Jenny Hoffmann
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | - Sonja Gostek
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | - Thomas Schettgen
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | - Natalia Quinete
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany.,Southeast Environmental Research Center, Florida International University Florida, Florida, USA
| | | | - Thomas Kraus
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | - Patrick Ziegler
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany.
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21
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Kania-Korwel I, Lukasiewicz T, Barnhart CD, Stamou M, Chung H, Kelly KM, Bandiera S, Lein PJ, Lehmler HJ. Editor's Highlight: Congener-Specific Disposition of Chiral Polychlorinated Biphenyls in Lactating Mice and Their Offspring: Implications for PCB Developmental Neurotoxicity. Toxicol Sci 2018; 158:101-115. [PMID: 28431184 DOI: 10.1093/toxsci/kfx071] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Chiral polychlorinated biphenyl (PCB) congeners have been implicated by laboratory and epidemiological studies in PCB developmental neurotoxicity. These congeners are metabolized by cytochrome P450 (P450) enzymes to potentially neurotoxic hydroxylated metabolites (OH-PCBs). The present study explores the enantioselective disposition and toxicity of 2 environmentally relevant, neurotoxic PCB congeners and their OH-PCB metabolites in lactating mice and their offspring following dietary exposure of the dam. Female C57BL/6N mice (8-weeks old) were fed daily, beginning 2 weeks prior to conception and continuing throughout gestation and lactation, with 3.1 µmol/kg bw/d of racemic 2,2',3,5',6-pentachlorobiphenyl (PCB 95) or 2,2',3,3',6,6'-hexachlorobiphenyl (PCB 136) in peanut butter; controls received vehicle (peanut oil) in peanut butter. PCB 95 levels were higher than PCB 136 levels in both dams and pups, consistent with the more rapid metabolism of PCB 136 compared with PCB 95. In pups and dams, both congeners were enriched for the enantiomer eluting second on enantioselective gas chromatography columns. OH-PCB profiles in lactating mice and their offspring were complex and varied according to congener, tissue and age. Developmental exposure to PCB 95 versus PCB 136 differentially affected the expression of P450 enzymes as well as neural plasticity (arc and ppp1r9b) and thyroid hormone-responsive genes (nrgn and mbp). The results suggest that the enantioselective metabolism of PCBs to OH-PCBs may influence neurotoxic outcomes following developmental exposures, a hypothesis that warrants further investigation.
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Affiliation(s)
- Izabela Kania-Korwel
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa
| | - Tracy Lukasiewicz
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa
| | - Christopher D Barnhart
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California
| | - Marianna Stamou
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California
| | - Haeun Chung
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Kevin M Kelly
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa
| | - Stelvio Bandiera
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa
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22
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Nagayoshi H, Kakimoto K, Konishi Y, Kajimura K, Nakano T. Determination of the human cytochrome P450 monooxygenase catalyzing the enantioselective oxidation of 2,2',3,5',6-pentachlorobiphenyl (PCB 95) and 2,2',3,4,4',5',6-heptachlorobiphenyl (PCB 183). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:16420-16426. [PMID: 29043584 DOI: 10.1007/s11356-017-0434-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 10/05/2017] [Indexed: 04/16/2023]
Abstract
2,2',3,5',6-Pentachlorobiphenyl (PCB 95) and 2,2',3,4,4',5',6-heptachlorobiphenyl (PCB 183) possess axial chirality and form the aS and aR enantiomers. The enantiomers of these congeners have been reported to accumulate in the human body enantioselectively via unknown mechanisms. In this study, we determined the cytochrome P450 (CYP) monooxygenase responsible for the enantioselective oxidization of PCB 95 and PCB 183, using a recombinant human CYP monooxygenase. We evaluated 13 CYP monooxygenases, namely CYP1A1, CYP1A2, CYP1B1, CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2E1, CYP2J2, CYP3A4, CYP3A5, CYP4F2, and aromatase (CYP19), and revealed that CYP2A6 preferably oxidizes aS-PCB 95 enantioselectively; however, it did not oxidize PCB 183. The enantiomer composition was elevated from 0.5 (racemate) to 0.54. In addition, following incubation with CYP2A6, the enantiomer fraction (EF) of PCB 95 demonstrated a time-dependent increase.
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Key Words
- 2,2′,3,4,4′,5′,6-heptachlorobiphenyl
- 2,2′,3,5′,6-pentachlorobiphenyl
- Cytochrome P450 2A6
- Enantiomer
- Enantioselective analysis
- Enantioselective oxidation
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Affiliation(s)
- Haruna Nagayoshi
- Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka, 537-0025, Japan.
| | - Kensaku Kakimoto
- Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka, 537-0025, Japan
| | - Yoshimasa Konishi
- Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka, 537-0025, Japan
| | - Keiji Kajimura
- Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka, 537-0025, Japan
| | - Takeshi Nakano
- Research Center for Environment Preservation, Osaka University, 2-4 Yamadaoka, Suita, Osaka, 565-0871, Japan
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23
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Li X, Parkin SR, Lehmler HJ. Absolute configuration of 2,2',3,3',6-pentachlorinatedbiphenyl (PCB 84) atropisomers. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:16402-16410. [PMID: 28537024 PMCID: PMC5823790 DOI: 10.1007/s11356-017-9259-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 05/10/2017] [Indexed: 05/05/2023]
Abstract
Nineteen polychlorinated biphenyl (PCB) congeners, such as 2,2',3,3',6-pentachlorobiphenyl (PCB 84), display axial chirality because they form stable rotational isomers, or atropisomers, that are non-superimposable mirror images of each other. Although chiral PCBs undergo atropselective biotransformation and atropselectively alter biological processes, the absolute structure of only a few PCB atropisomers has been determined experimentally. To help close this knowledge gap, pure PCB 84 atropisomers were obtained by semi-preparative liquid chromatography with two serially connected Nucleodex β-PM columns. The absolute configuration of both atropisomers was determined by X-ray single-crystal diffraction. The PCB 84 atropisomer eluting first and second on the Nucleodex β-PM column correspond to (aR)-(-)-PCB 84 and (aS)-(+)-PCB 84, respectively. Enantioselective gas chromatographic analysis with the β-cyclodextrin-based CP-Chirasil-Dex CB gas chromatography column showed the same elution order as the Nucleodex β-PM column. Based on earlier reports, the atropisomers eluting first and second on the BGB-172 gas chromatography column are (aR)-(-)-PCB 84 and (aS)-(+)-PCB 84, respectively. An inversion of the elution order is observed on the Cyclosil-B gas chromatography and Cellulose-3 liquid chromatography columns. These results advance the interpretation of environmental and human biomonitoring as well as toxicological studies.
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Affiliation(s)
- Xueshu Li
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, IA, 52242, USA
| | - Sean R Parkin
- Department of Chemistry, University of Kentucky, Lexington, KY, 40506, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, IA, 52242, USA.
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24
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Megson D, Brown TA, O'Sullivan G, Robson M, Ortiz X, Worsfold PJ, Comber S, Lohan MC, Reiner EJ. Changes to polychlorinated biphenyl (PCB) signatures and enantiomer fractions across different tissue types in Guillemots. MARINE POLLUTION BULLETIN 2018; 131:174-179. [PMID: 29886934 DOI: 10.1016/j.marpolbul.2018.04.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 04/06/2018] [Accepted: 04/08/2018] [Indexed: 06/08/2023]
Abstract
Two Guillemot carcases were dissected, each providing 12 discrete tissue samples and 3 samples of partially digested food. One hundred and five PCBs from the 209 PCBs determined by GCxGC-ToFMS were detected. The relative proportions of individual PCBs did not vary greatly within tissue types, although the PCB profile from undigested food could be distinguished. Enantiomer fractions (EFs) were determined for CB-95, CB-136 and CB-149 by GC-HRqToFMS. EFs in the partially digested food were near racemic, with high levels of enrichment for E1 CB-95 in the kidneys and liver (EF of 0.80 and 0.84 respectively). This provides some of the clearest evidence to date that fractionation takes place in the organs where metabolic biotransformation and elimination of PCBs occurs. Our findings also confirm the ability of non-lethal sampling techniques, such as collection of small (<1 g) blood samples, to provide PCB signatures that are representative of an individual organism.
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Affiliation(s)
- David Megson
- School of Science and the Environment, Manchester Metropolitan University, Manchester M1 5GD, UK; Biogeochemistry Research Centre, SoGEES, Plymouth University, Plymouth, Devon PL4 8AA, UK.
| | - Thomas A Brown
- Biogeochemistry Research Centre, SoGEES, Plymouth University, Plymouth, Devon PL4 8AA, UK; Marine Ecology and Chemistry, Scottish Association for Marine Science, Oban PA37 1QA, UK
| | - Gwen O'Sullivan
- Department of Earth & Environmental Science, Mount Royal University, 4825 Mount Royal Gate SW, Calgary, Alberta T3E 6K6, Canada
| | - Matthew Robson
- Ontario Ministry of the Environment and Climate Change, 125 Resources Road, Toronto, Ontario M9P 3V6, Canada
| | - Xavier Ortiz
- Ontario Ministry of the Environment and Climate Change, 125 Resources Road, Toronto, Ontario M9P 3V6, Canada
| | - Paul J Worsfold
- Biogeochemistry Research Centre, SoGEES, Plymouth University, Plymouth, Devon PL4 8AA, UK
| | - Sean Comber
- Biogeochemistry Research Centre, SoGEES, Plymouth University, Plymouth, Devon PL4 8AA, UK
| | - Maeve C Lohan
- Biogeochemistry Research Centre, SoGEES, Plymouth University, Plymouth, Devon PL4 8AA, UK
| | - Eric J Reiner
- Ontario Ministry of the Environment and Climate Change, 125 Resources Road, Toronto, Ontario M9P 3V6, Canada
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25
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Pěnčíková K, Brenerová P, Svržková L, Hrubá E, Pálková L, Vondráček J, Lehmler HJ, Machala M. Atropisomers of 2,2',3,3',6,6'-hexachlorobiphenyl (PCB 136) exhibit stereoselective effects on activation of nuclear receptors in vitro. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:16411-16419. [PMID: 29124635 PMCID: PMC5943194 DOI: 10.1007/s11356-017-0683-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 11/02/2017] [Indexed: 04/16/2023]
Abstract
PCB 136 is an environmentally relevant chiral PCB congener, which has been found in vivo to be present in form of rotational isomers (atropisomers). Its atropselective biotransformation or neurotoxic effects linked with sensitization of ryanodine receptor suggest that it might interact also with other intracellular receptors in a stereospecific manner. However, possible atropselective effects of PCB 136 on nuclear receptor transactivation remain unknown. Therefore, in this study, atropselective effects of PCB 136 on nuclear receptors controlling endocrine signaling and/or expression of xenobiotic and steroid hormone catabolism were investigated. PCB136 atropisomers were found to exert differential effects on estrogen receptor (ER) activation; (+)-PCB 136 was estrogenic, while (-)-PCB 136 was antiestrogenic. In contrast, inhibition of androgen receptor (AR) activity was not stereospecific. Both PCB136 stereoisomers induced the constitutive androgen receptor (CAR)-dependent gene expression; however, no significant stereospecificity of PCB 136 atropisomers was observed. PCB136 was a partial inducer of the pregnane X receptor (PXR)-dependent gene expression. Here, (-)-PCB 136 was a significantly more potent inducer of PXR activity than (+)-PCB 136. Taken together, the present results indicate that at least two nuclear receptors participating in endocrine regulation or metabolism, ER and PXR, could be regulated in an atropselective manner by chiral PCB 136. The enantioselective enrichment of PCB atropisomers in animal and human tissues may thus have significant consequences for endocrine-disrupting effects of chiral ortho-substituted PCB congeners.
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Affiliation(s)
- Kateřina Pěnčíková
- Department of Chemistry and Toxicology, Veterinary Research Institute, 62100, Brno, Czech Republic
| | - Petra Brenerová
- Department of Chemistry and Toxicology, Veterinary Research Institute, 62100, Brno, Czech Republic
| | - Lucie Svržková
- Department of Chemistry and Toxicology, Veterinary Research Institute, 62100, Brno, Czech Republic
| | - Eva Hrubá
- Department of Chemistry and Toxicology, Veterinary Research Institute, 62100, Brno, Czech Republic
| | - Lenka Pálková
- Department of Chemistry and Toxicology, Veterinary Research Institute, 62100, Brno, Czech Republic
| | - Jan Vondráček
- Department of Cytokinetics, Institute of Biophysics of the Czech Academy of Sciences, 62165, Brno, Czech Republic
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA, 52242, USA
| | - Miroslav Machala
- Department of Chemistry and Toxicology, Veterinary Research Institute, 62100, Brno, Czech Republic.
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26
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Dhakal K, Gadupudi GS, Lehmler HJ, Ludewig G, Duffel MW, Robertson LW. Sources and toxicities of phenolic polychlorinated biphenyls (OH-PCBs). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:16277-16290. [PMID: 28744683 PMCID: PMC5785587 DOI: 10.1007/s11356-017-9694-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 06/30/2017] [Indexed: 04/16/2023]
Abstract
Polychlorinated biphenyls (PCBs), a group of 209 congeners that differ in the number and position of chlorines on the biphenyl ring, are anthropogenic chemicals that belong to the persistent organic pollutants (POPs). For many years, PCBs have been a topic of interest because of their biomagnification in the food chain and their environmental persistence. PCBs with fewer chlorine atoms, however, are less persistent and more susceptible to metabolic attack, giving rise to chemicals characterized by the addition of one or more hydroxyl groups to the chlorinated biphenyl skeleton, collectively known as hydroxylated PCBs (OH-PCBs). In animals and plants, this biotransformation of PCBs to OH-PCBs is primarily carried out by cytochrome P-450-dependent monooxygenases. One of the reasons for infrequent detection of lower chlorinated PCBs in serum and other biological matrices is their shorter half-lives, and their metabolic transformation, resulting in OH-PCBs or their conjugates, such as sulfates and glucuronides, or macromolecule adducts. Recent biomonitoring studies have reported the presence of OH-PCBs in human serum. The occurrence of OH-PCBs, the size of this group (there are 837 mono-hydroxyl PCBs alone), and their wide spectra of physical characteristics (pKa's and log P's ranging over 5 to 6 orders of magnitude) give rise to a multiplicity of biological effects. Among those are bioactivation to electrophilic metabolites that can form covalent adducts with DNA and other macromolecules, interference with hormonal signaling, inhibition of enzymes that regulate cellular concentrations of active hormones, and interference with the transport of hormones. This new information creates an urgent need for a new perspective on these often overlooked metabolites.
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Affiliation(s)
- Kiran Dhakal
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus #219 IREH, Iowa City, IA, 52242-5000, USA
| | - Gopi S Gadupudi
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus #219 IREH, Iowa City, IA, 52242-5000, USA
| | - Hans-Joachim Lehmler
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus #219 IREH, Iowa City, IA, 52242-5000, USA
| | - Gabriele Ludewig
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus #219 IREH, Iowa City, IA, 52242-5000, USA
| | - Michael W Duffel
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, The University of Iowa, Iowa City, IA, USA
| | - Larry W Robertson
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA.
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus #219 IREH, Iowa City, IA, 52242-5000, USA.
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27
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Yao M, Hu T, Wang Y, Du Y, Hu C, Wu R. Polychlorinated biphenyls and its potential role in endometriosis. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 229:837-845. [PMID: 28774553 DOI: 10.1016/j.envpol.2017.06.088] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 06/19/2017] [Accepted: 06/26/2017] [Indexed: 06/07/2023]
Abstract
With the progress of global industrialization and environmental deterioration, the relationship between human health and the living environment has become an increasing focus of attention. Polychlorinated biphenyls (PCBs, including dioxin-like polychlorinated biphenyls and non-dioxin-like polychlorinated biphenyls), as part of the organic chlorine contaminants, have been suspected as playing a role in the etiopathogenesis of endometriosis. Several population-based studies have proposed that exposure to PCBs may increase the risk of developing endometriosis, while some epidemiological studies have failed to find any association between PCBs and endometriosis. The purpose of this review is to discuss the potential pathophysiological relationship between endometriosis and PCBs with a focus on both dioxin-like polychlorinated biphenyls and non-dioxin-like polychlorinated biphenyls.
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Affiliation(s)
- Mengyun Yao
- Department of Gynecology, Women's Hospital, School of Medicine, Zhejiang University, 1Xueshi Road, Hangzhou 310006, P.R. China
| | - Tingting Hu
- Department of Gynecology, Women's Hospital, School of Medicine, Zhejiang University, 1Xueshi Road, Hangzhou 310006, P.R. China
| | - Yinfeng Wang
- Department of Gynecology, Women's Hospital, School of Medicine, Zhejiang University, 1Xueshi Road, Hangzhou 310006, P.R. China
| | - Yongjiang Du
- Department of Gynecology, Women's Hospital, School of Medicine, Zhejiang University, 1Xueshi Road, Hangzhou 310006, P.R. China
| | - Changchang Hu
- Department of Gynecology, Women's Hospital, School of Medicine, Zhejiang University, 1Xueshi Road, Hangzhou 310006, P.R. China
| | - Ruijin Wu
- Department of Gynecology, Women's Hospital, School of Medicine, Zhejiang University, 1Xueshi Road, Hangzhou 310006, P.R. China.
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28
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Kumar R, Mota LC, Litoff EJ, Rooney JP, Boswell WT, Courter E, Henderson CM, Hernandez JP, Corton JC, Moore DD, Baldwin WS. Compensatory changes in CYP expression in three different toxicology mouse models: CAR-null, Cyp3a-null, and Cyp2b9/10/13-null mice. PLoS One 2017; 12:e0174355. [PMID: 28350814 PMCID: PMC5370058 DOI: 10.1371/journal.pone.0174355] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/07/2017] [Indexed: 12/12/2022] Open
Abstract
Targeted mutant models are common in mechanistic toxicology experiments investigating the absorption, metabolism, distribution, or elimination (ADME) of chemicals from individuals. Key models include those for xenosensing transcription factors and cytochrome P450s (CYP). Here we investigated changes in transcript levels, protein expression, and steroid hydroxylation of several xenobiotic detoxifying CYPs in constitutive androstane receptor (CAR)-null and two CYP-null mouse models that have subfamily members regulated by CAR; the Cyp3a-null and a newly described Cyp2b9/10/13-null mouse model. Compensatory changes in CYP expression that occur in these models may also occur in polymorphic humans, or may complicate interpretation of ADME studies performed using these models. The loss of CAR causes significant changes in several CYPs probably due to loss of CAR-mediated constitutive regulation of these CYPs. Expression and activity changes include significant repression of Cyp2a and Cyp2b members with corresponding drops in 6α- and 16β-testosterone hydroxylase activity. Further, the ratio of 6α-/15α-hydroxylase activity, a biomarker of sexual dimorphism in the liver, indicates masculinization of female CAR-null mice, suggesting a role for CAR in the regulation of sexually dimorphic liver CYP profiles. The loss of Cyp3a causes fewer changes than CAR. Nevertheless, there are compensatory changes including gender-specific increases in Cyp2a and Cyp2b. Cyp2a and Cyp2b were down-regulated in CAR-null mice, suggesting activation of CAR and potentially PXR following loss of the Cyp3a members. However, the loss of Cyp2b causes few changes in hepatic CYP transcript levels and almost no significant compensatory changes in protein expression or activity with the possible exception of 6α-hydroxylase activity. This lack of a compensatory response in the Cyp2b9/10/13-null mice is probably due to low CYP2B hepatic expression, especially in male mice. Overall, compensatory and regulatory CYP changes followed the order CAR-null > Cyp3a-null > Cyp2b-null mice.
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Affiliation(s)
- Ramiya Kumar
- Biological Sciences, Clemson University, Clemson, SC, United States of America
| | - Linda C. Mota
- Environmental Toxicology, Clemson University, Pendleton, SC, United States of America
| | - Elizabeth J. Litoff
- Biological Sciences, Clemson University, Clemson, SC, United States of America
| | - John P. Rooney
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - W. Tyler Boswell
- Biological Sciences, Clemson University, Clemson, SC, United States of America
| | - Elliott Courter
- Biological Sciences, Clemson University, Clemson, SC, United States of America
| | | | - Juan P. Hernandez
- Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States of America
| | | | - David D. Moore
- Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States of America
| | - William S. Baldwin
- Biological Sciences, Clemson University, Clemson, SC, United States of America
- Environmental Toxicology, Clemson University, Pendleton, SC, United States of America
- * E-mail:
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29
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Uwimana E, Maiers A, Li X, Lehmler HJ. Microsomal Metabolism of Prochiral Polychlorinated Biphenyls Results in the Enantioselective Formation of Chiral Metabolites. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:1820-1829. [PMID: 28038482 PMCID: PMC5300040 DOI: 10.1021/acs.est.6b05387] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/23/2016] [Accepted: 12/30/2016] [Indexed: 05/20/2023]
Abstract
Polychlorinated biphenyl (PCB) congeners with multiple ortho chlorine substituents and their metabolites exist as stable rotational isomers, or atropisomers, that are nonsuperimposable mirror images of each other. Additionally, the oxidation of certain axially prochiral PCBs, such as 2,2',4,6'-tetrachlorobiphenyl (PCB 51) and 2,2',4,5,6'-pentachlorobiphenyl (PCB 102), in the meta position of the symmetrically substituted phenyl ring is expected to form axially chiral hydroxylated metabolites (OH-PCBs); however, the formation of chiral OH-PCBs from prochiral PCBs has not been demonstrated experimentally. Here, we investigate if the oxidation of PCB 51 and PCB 102 by different microsomal preparations results in the formation of chiral OH-PCBs. Gas chromatographic analysis revealed that PCB 51 and PCB 102 were metabolized to 2,2',4,6'-tetrachlorobiphenyl-3'-ol (OH-PCB 51) and 2,2',4,5,6'-pentachlorobiphenyl-3'-ol (OH-PCB 102), respectively, by liver microsomes from male rats pretreated with different inducers; untreated male monkeys, guinea pigs, rabbits, and hamsters; and female dogs. The formation of both metabolites was inducer- and species-dependent. Both OH-PCB 51 and OH-PCB 102 were chiral and formed enantioselectively by all microsomal preparations investigated. These findings demonstrate that axially chiral PCB metabolites are formed from axially prochiral PCB congeners, a fact that should be considered when studying the environmental fate, transport, and toxicity of OH-PCBs.
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Uwimana E, Li X, Lehmler HJ. 2,2',3,5',6-Pentachlorobiphenyl (PCB 95) Is Atropselectively Metabolized to para-Hydroxylated Metabolites by Human Liver Microsomes. Chem Res Toxicol 2016; 29:2108-2110. [PMID: 27989147 PMCID: PMC5175585 DOI: 10.1021/acs.chemrestox.6b00371] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Exposure
to neurotoxic, chiral PCBs has been associated with neurodevelopmental
disorders, but their metabolism in humans remains unexplored. We investigated
the enantioselective metabolism of PCB 95 by human liver microsomes
(HLMs) to potentially neurotoxic, hydroxylated metabolites (OH-PCBs).
OH-PCB profiles formed in experiments with HLMs differed from metabolite
profiles reported for rodent species. The second eluting atropisomer
of 2,2′,3,5′,6-pentachlorobiphenyl-4′-ol, the
major metabolite, was preferentially formed by all HLM preparations
investigated. Differences in metabolite formation rates were observed
with single donor HLMs. The metabolism of PCBs and its role in PCB-mediated
neurodevelopmental disorders need to be further characterized.
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Affiliation(s)
- Eric Uwimana
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa , Iowa City, Iowa 52242, United States
| | - Xueshu Li
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa , Iowa City, Iowa 52242, United States
| | - Hans-Joachim Lehmler
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa , Iowa City, Iowa 52242, United States
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31
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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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32
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Chai T, Cui F, Mu X, Yang Y, Qi S, Zhu L, Wang C, Qiu J. Stereoselective induction by 2,2',3,4',6-pentachlorobiphenyl in adult zebrafish (Danio rerio): Implication of chirality in oxidative stress and bioaccumulation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 215:66-76. [PMID: 27179325 DOI: 10.1016/j.envpol.2016.04.075] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 04/18/2016] [Accepted: 04/21/2016] [Indexed: 06/05/2023]
Abstract
This study aimed to investigate the oxidative stress process and bioaccumulation the racemic/(-)-/(+)- 2,2',3,4',6-pentachlorobiphenyl were administered to adult zebrafish (Danio rerio) after prolonged exposure of 56-days uptake and 49-days depuration experiments. Stereoselective accumulation was observed in adult samples after racemic exposure as revealed by decreased enantiomer fractions. The two enantiomers of PCB91 accumulated at different rates with logBCFk values close to 3.7, suggesting that they were highly hazardous and persistent pollutants. Exposure to racemic/(-)-/(+)- PCB91 stereoselectively induced oxidative stress owing to changes in reactive oxygen species, malondialdehyde contents, antioxidant enzyme activities and gene expressions in brain and liver tissues. In addition, the stereoselective relationship between bioconcentration and oxidative stress were also presented in this study. Our findings might be helpful for elucidating the environmental risk of the two enantiomers of PCB91 that induce toxicity in aquatic organisms.
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Affiliation(s)
- Tingting Chai
- College of Science, China Agricultural University, Beijing 100193, China; Institute of Quality Standards & Testing Technology for Agro-Products, Key Laboratory of Agro-product Quality and Safety, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Feng Cui
- College of Science, China Agricultural University, Beijing 100193, China
| | - Xiyan Mu
- College of Science, China Agricultural University, Beijing 100193, China
| | - Yang Yang
- College of Science, China Agricultural University, Beijing 100193, China
| | - Suzhen Qi
- College of Science, China Agricultural University, Beijing 100193, China
| | - Lizhen Zhu
- College of Science, China Agricultural University, Beijing 100193, China
| | - Chengju Wang
- College of Science, China Agricultural University, Beijing 100193, China.
| | - Jing Qiu
- Institute of Quality Standards & Testing Technology for Agro-Products, Key Laboratory of Agro-product Quality and Safety, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China.
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33
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Zheng J, Yu LH, Chen SJ, Hu GC, Chen KH, Yan X, Luo XJ, Zhang S, Yu YJ, Yang ZY, Mai BX. Polychlorinated Biphenyls (PCBs) in Human Hair and Serum from E-Waste Recycling Workers in Southern China: Concentrations, Chiral Signatures, Correlations, and Source Identification. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:1579-86. [PMID: 26757157 DOI: 10.1021/acs.est.5b04955] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Hair is increasingly used as a biomarker for human exposure to persistent organic pollutants (POPs). However, the internal and external sources of hair POPs remain a controversial issue. This study analyzed polychlorinated biphenyls (PCBs) in human hair and serum from electronic waste recycling workers. The median concentrations were 894 ng/g and 2868 ng/g lipid in hair and serum, respectively. The PCB concentrations in male and female serum were similar, while concentrations in male hair were significantly lower than in female hair. Significant correlations between the hair and serum PCB levels and congener profiles suggest that air is the predominant PCB source in hair and that hair and blood PCB levels are largely dependent on recent accumulation. The PCB95, 132, and 183 chiral signatures in serum were significantly nonracemic, with mean enantiomer fractions (EFs) of 0.440-0.693. Nevertheless, the hair EFs were essentially racemic (mean EFs = 0.495-0.503). Source apportionment using the Chemical Mass Balance model also indicated primary external PCB sources in human hair from the study area. Air, blood, and indoor dust are responsible for, on average, 64.2%, 27.2%, and 8.79% of the hair PCBs, respectively. This study evidenced that hair is a reliable matrix for monitoring human POP exposure.
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Affiliation(s)
- Jing Zheng
- Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection , Guangzhou 510655, China
| | - Le-Huan Yu
- Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection , Guangzhou 510655, China
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, China
| | - She-Jun Chen
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, China
| | - Guo-Cheng Hu
- Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection , Guangzhou 510655, China
| | - Ke-Hui Chen
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Xiao Yan
- State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-Sen University , Guangzhou 510275, China
| | - Xiao-Jun Luo
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, China
| | - Sukun Zhang
- Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection , Guangzhou 510655, China
| | - Yun-Jiang Yu
- Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection , Guangzhou 510655, China
| | - Zhong-Yi Yang
- State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-Sen University , Guangzhou 510275, China
| | - Bi-Xian Mai
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, China
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34
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Wu X, Lehmler HJ. Effects of thiol antioxidants on the atropselective oxidation of 2,2',3,3',6,6'-hexachlorobiphenyl (PCB 136) by rat liver microsomes. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:2081-8. [PMID: 26155892 PMCID: PMC4706823 DOI: 10.1007/s11356-015-4987-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 06/30/2015] [Indexed: 05/20/2023]
Abstract
Chiral polychlorinated biphenyl (PCB) congeners, such as PCB 136, are atropselectively metabolized to various hydroxylated PCB metabolites (HO-PCBs). The present study investigates the effect of two thiol antioxidants, glutathione and N-acetyl-cysteine (NAC), on profiles and chiral signatures of PCB 136 and its HO-PCB metabolites in rat liver microsomal incubations. Liver microsomes prepared from rats pretreated with phenobarbital were incubated with PCB 136 (5 μM) in the presence of the respective antioxidant (0-10 mM), and levels and chiral signatures of PCB 136 and its HO-PCB metabolites were determined. Three metabolites, 5-136 (2,2',3,3',6,6'-hexachlorobiphenyl-5-ol), 4-136 (2,2',3,3',6,6'-hexachlorobiphenyl-4-ol), and 4,5-136 (2,2',3,3',6,6'-hexachlorobiphenyl-4,5-diol), were detected in all incubations, with 5-136 being the major metabolite. Compared to microsomal incubations without antioxidant, levels of 4,5-136 increased with increasing antioxidant concentration, whereas levels of PCB 136 and both mono-HO-PCBs were not affected by the presence of either antioxidant. PCB 136, 4-136, and 5-136 displayed significant atropisomeric enrichment; however, the direction and extent of the atropisomeric enrichment was not altered in the presence of an antioxidant. Because 4,5-136 can either be conjugated to a sulfate or glucuronide metabolite that is readily excreted or further oxidized a potentially toxic PCB 136 quinone, the effect of both thiol antioxidants on 4,5-136 formation suggests that disruptions of glutathione homeostasis may alter the balance between both metabolic pathways and, thus, PCB 136 toxicity in vivo.
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Affiliation(s)
- Xianai Wu
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, University of Iowa Research Park, #221 IREH, Iowa City, IA, 52242-5000, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, University of Iowa Research Park, #221 IREH, Iowa City, IA, 52242-5000, USA.
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35
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Ma C, Zhai G, Wu H, Kania-Korwel I, Lehmler HJ, Schnoor JL. Identification of a novel hydroxylated metabolite of 2,2',3,5',6-pentachlorobiphenyl formed in whole poplar plants. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:2089-98. [PMID: 26676542 PMCID: PMC4718877 DOI: 10.1007/s11356-015-5939-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 12/07/2015] [Indexed: 05/20/2023]
Abstract
Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants consisting of 209 congeners. Oxidation of several PCB congeners to hydroxylated PCBs (OH-PCBs) in whole poplar plants has been reported before. Moreover, 2,2',3,5',6-pentachlorobiphenyl (PCB95), as a chiral congener, has been previously shown to be atropselectively taken up and transformed in whole poplar plants. The objective of this study was to determine if PCB95 is atropselectively metabolized to OH-PCBs in whole poplar plants. Two hydroxylated PCB95s were detected by high-performance liquid chromatography-mass spectrometry in the roots of whole poplar plants exposed to racemic PCB95 for 30 days. The major metabolite was confirmed to be 4'-hydroxy-2,2',3,5',6-pentachlorobiphenyl (4'-OH-PCB95) by gas chromatography-mass spectrometry (GC-MS) using an authentic reference standard. Enantioselective analysis showed that 4'-OH-PCB95 was formed atropselectively, with the atropisomer eluting second on the Nucleodex β-PM column (E2-4'-OH-PCB95) being slightly more abundant in the roots of whole poplar plants. Therefore, PCB95 can at least be metabolized into 4'-OH-PCB95 and another unknown hydroxylated PCB95 (as a minor metabolite) in whole poplar plants. Both atropisomers of 4'-OH-PCB95 are formed, but E2-4'-OH-PCB95 has greater atropisomeric enrichment in the roots of whole poplar plants. A comparison with mammalian biotransformation studies indicates a distinctively different metabolite profile of OH-PCB95 metabolites in whole poplar plants. Our observations suggest that biotransformation of chiral PCBs to OH-PCBs by plants may represent an important source of enantiomerically enriched OH-PCBs in the environment.
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Affiliation(s)
- Cunxian Ma
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA, 52242, USA
| | - Guangshu Zhai
- Department of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, The University of Iowa, Iowa City, IA, 52242, USA
| | - Huimin Wu
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA, 52242, USA
| | - Izabela Kania-Korwel
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA, 52242, USA
| | - Hans-Joachim Lehmler
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA, 52242, USA
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA, 52242, USA
| | - Jerald L Schnoor
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA, 52242, USA.
- Department of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, The University of Iowa, Iowa City, IA, 52242, USA.
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA, 52242, USA.
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36
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Kania-Korwel I, Lehmler HJ. Chiral polychlorinated biphenyls: absorption, metabolism and excretion--a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:2042-57. [PMID: 25651810 PMCID: PMC4527964 DOI: 10.1007/s11356-015-4150-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 01/19/2015] [Indexed: 05/20/2023]
Abstract
Seventy eight out of the 209 possible polychlorinated biphenyl (PCB) congeners are chiral, 19 of which exist under ambient conditions as stable rotational isomers that are non-superimposable mirror images of each other. These congeners (C-PCBs) represent up to 6 % by weight of technical PCB mixtures and undergo considerable atropisomeric enrichment in wildlife, laboratory animals, and humans. The objective of this review is to summarize our current knowledge of the processes involved in the absorption, metabolism, and excretion of C-PCBs and their metabolites in laboratory animals and humans. C-PCBs are absorbed and excreted by passive diffusion, a process that, like other physicochemical processes, is inherently not atropselective. In mammals, metabolism by cytochrome P450 (P450) enzymes represents a major route of elimination for many C-PCBs. In vitro studies demonstrate that C-PCBs with a 2,3,6-trichlorosubstitution pattern in one phenyl ring are readily oxidized to hydroxylated PCB metabolites (HO-PCBs) by P450 enzymes, such as rat CYP2B1, human CYP2B6, and dog CYP2B11. The oxidation of C-PCBs is atropselective, thus resulting in a species- and congener-dependent atropisomeric enrichment of C-PCBs and their metabolites. This atropisomeric enrichment of C-PCBs and their metabolites likely plays a poorly understood role in the atropselective toxicity of C-PCBs and, therefore, warrants further investigation.
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Affiliation(s)
- Izabela Kania-Korwel
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, UI Research Park, Iowa City, IA, 52242, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, UI Research Park, Iowa City, IA, 52242, USA.
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37
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Kania-Korwel I, Lehmler HJ. Toxicokinetics of chiral polychlorinated biphenyls across different species--a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:2058-80. [PMID: 25824003 PMCID: PMC4591098 DOI: 10.1007/s11356-015-4383-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 03/16/2015] [Indexed: 05/22/2023]
Abstract
Nineteen polychlorinated biphenyls (chiral or C-PCBs) exist as two stable rotational isomers (atropisomers) that are non-superimposable mirror images of each other. C-PCBs are released into the environment as racemic (i.e., equal) mixtures of both atropisomers and undergo atropisomeric enrichment due to biological, but not abiotic, processes. In particular, toxicokinetic studies provide important initial insights into atropselective processes involved in the disposition (i.e., absorption, distribution, biotransformation, and excretion) of C-PCBs. The toxicokinetic of C-PCBs is highly congener and species dependent. In particular, at lower trophic levels, abiotic processes play a predominant role in C-PCB toxicokinetics. Biotransformation plays an important role in the elimination of C-PCBs in mammals. The elimination of C-PCB follows the approximate order mammals > birds > amphibians > fish, mostly due to a corresponding decrease in metabolic capacity. A few studies have shown differences in the toxicokinetics of C-PCB atropisomers; however, more work is needed to understand the toxicokinetics of C-PCBs and the underlying biological processes. Such studies will not only contribute to our understanding of the fate of C-PCBs in aquatic and terrestrial food webs but also facilitate our understanding of human exposures to C-PCBs.
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Affiliation(s)
- Izabela Kania-Korwel
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, UI Research Park, #221 IREH, Iowa City, IA, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, UI Research Park, #221 IREH, Iowa City, IA, USA.
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38
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Liang Y, Wang P, Liu D, Zhan J, Luo M, Han J, Jing X, Yao G, Zhou Z. The enantioselective metabolic mechanism of quizalofop-ethyl and quizalofop-acid enantiomers in animal: protein binding, intestinal absorption, and in vitro metabolism in plasma and the microsome. RSC Adv 2016. [DOI: 10.1039/c6ra19391a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The effects of protein binding (pepsin, trypsin and serum albumin), intestinal absorption (everted gut sac), and degradation (plasma, liver microsome and cytosol) on the enantioselectivity of quizalofop-ethyl in animals were studiedin vitro.
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Affiliation(s)
- Yiran Liang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Science
- China Agricultural University
- Department of Applied Chemistry
- Beijing 100193
| | - Peng Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Science
- China Agricultural University
- Department of Applied Chemistry
- Beijing 100193
| | - Donghui Liu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Science
- China Agricultural University
- Department of Applied Chemistry
- Beijing 100193
| | - Jing Zhan
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Science
- China Agricultural University
- Department of Applied Chemistry
- Beijing 100193
| | - Mai Luo
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Science
- China Agricultural University
- Department of Applied Chemistry
- Beijing 100193
| | - Jiajun Han
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Science
- China Agricultural University
- Department of Applied Chemistry
- Beijing 100193
| | - Xu Jing
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Science
- China Agricultural University
- Department of Applied Chemistry
- Beijing 100193
| | - Guojun Yao
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Science
- China Agricultural University
- Department of Applied Chemistry
- Beijing 100193
| | - Zhiqiang Zhou
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Science
- China Agricultural University
- Department of Applied Chemistry
- Beijing 100193
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39
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Chen Z, Chen H, Zou Y, Qiu J, Wen Y, Xu D. Are Nutrient Stresses Associated with Enantioselectivity of the Chiral Herbicide Imazethapyr in Arabidopsis thaliana? JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:10209-10217. [PMID: 26566036 DOI: 10.1021/acs.jafc.5b04495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Plant growth can be inhibited by herbicides and is strongly limited by the availability of nutrients, which can influence human health through the food chain. Until now, however, cross talk between the enantioselectivity of herbicides and nutrient stresses has been poorly understood. We analyzed trace element and macroelement contents in shoots of Arabidopsis thaliana treated by the chiral herbicide imazethapyr (IM) and observed that multiple-nutrient stress (trace elements Mn, Cu, and Fe and macroelements P, K, Ca, and Mg) was enantioselective. The (R)-IM treatments resulted in Mn 23.37%, Cu 63.53%, P 30.61%, K 63.70%, Ca 34.32%, and Mg 36.14% decreases compared with the control. Interestingly, it was also found that herbicidally active (R)-IM induced notable aggregation of nutrient elements in leaves and roots compared with the control and (S)-IM. Through gene expression analyses, it was found that herbicidally active (R)-IM induced the up- or down-regulation of genes involved in the transport of nutrient elements. We propose that (R)-IM affected the uptake and translocation of nutrient elements in A. thaliana, which destroyed the balance of nutrient elements in the plant. This finding reminds us to reconsider the effect of nutrient stresses in risk assessment of herbicides.
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Affiliation(s)
- Zunwei Chen
- Institute of Environmental Science, Zhejiang University , Hangzhou 310058, China
| | - Hui Chen
- Institute of Environmental Science, Zhejiang University , Hangzhou 310058, China
| | - Yuqin Zou
- Institute of Environmental Science, Zhejiang University , Hangzhou 310058, China
| | - Jiguo Qiu
- Institute of Environmental Science, Zhejiang University , Hangzhou 310058, China
| | - Yuezhong Wen
- Institute of Environmental Science, Zhejiang University , Hangzhou 310058, China
| | - Dongmei Xu
- College of Biological and Environmental Engineering, Zhejiang Shuren University , Hangzhou 310015, China
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Liu H, Zhang X, Dong Y, Chen C, Zhu S, Ma X. Enantioselective toxicities of chiral ionic liquids 1-alkyl-3-methyl imidazolium tartrate on Scenedesmus obliquus. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2015; 169:179-187. [PMID: 26554523 DOI: 10.1016/j.aquatox.2015.10.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/29/2015] [Accepted: 10/31/2015] [Indexed: 06/05/2023]
Abstract
Ionic liquids (ILs) are being used in various industries during the last few decades, while the good solubility and high stability of ILs may pose a potential threat to the aquatic environment. Effect of chiral ionic liquids (CILs) 1-alkyl-3-methyl imidazolium tartrate (RMIM T) on Scenedesmus obliquus (S.obliquus) was studied. The growth rate inhibition and cell membrane permeability increased with increasing RMIM T concentration and increasing alkyl chain lengths. The IC50 values of D-(-)-tartrate 1-hexyl-3-methyl imidazolium (D-(-)-HMIM T) were 28.30, 12.23,10.15 and 14.41 mg/L, respectively, at 24, 48, 72 and 96h. While that of L-(+)-tartrate 1-hexyl-3-methyl imidazolium (L-(+)-HMIM T) were 15.97, 7.91, 9.43 and 12.04 mg/L respectively. The concentration of chl a, chl b and chl (a+b) decreased with increasing RMIM T concentration. The chlorophyll fluorescence parameters (F0, Fv/Fm, Fv/F0, Y(II), ETR and NPQ) were affected by RMIM T, indicating that the RMIM T will damage the PSII, inhibit the transmission of excitation energy, decrease the efficiency of photosynthesis. The results showed that there were enantioselective toxicity of RMIM T to algae, and the toxicity of L-(+)-RMIM T was greater than that of D-(-)-RMIM T, but the enantioselective difference becomes smaller with increasing exposure time, and with the increasing carbon chain length of cation, indicating that cation properties may have a larger effect on toxicity than anion properties.
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Affiliation(s)
- Huijun Liu
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, China.
| | - Xiaoqiang Zhang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, China
| | - Ying Dong
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, China
| | - Caidong Chen
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, China
| | - Shimin Zhu
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, China
| | - Xiangjuan Ma
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, China
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41
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Subacute nicotine co-exposure has no effect on 2,2',3,5',6- pentachlorobiphenyl disposition but alters hepatic cytochrome P450 expression in the male rat. Toxicology 2015; 338:59-68. [PMID: 26463278 DOI: 10.1016/j.tox.2015.10.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 09/30/2015] [Accepted: 10/06/2015] [Indexed: 01/09/2023]
Abstract
Polychlorinated biphenyls (PCBs) are metabolized by cytochrome P450 2B enzymes (CYP2B) and nicotine is reported to alter CYP2B activity in the brain and liver. To test the hypothesis that nicotine influences PCB disposition, 2,2',3,5',6-pentachlorobiphenyl (PCB 95) and its metabolites were quantified in tissues of adult male Wistar rats exposed to PCB 95 (6mg/kg/d, p.o.) in the absence or presence of nicotine (1.0mg/kg/d of the tartrate salt, s.c.) for 7 consecutive days. PCB 95 was enantioselectively metabolized to hydroxylated (OH-) PCB metabolites, resulting in a pronounced enrichment of E1-PCB 95 in all tissues investigated. OH-PCBs were detected in blood and liver tissue, but were below the detection limit in adipose, brain and muscle tissues. Co-exposure to nicotine did not change PCB 95 disposition. CYP2B1 mRNA and CYP2B protein were not detected in brain tissues but were detected in liver. Co-exposure to nicotine and PCB 95 increased hepatic CYP2B1 mRNA but did not change CYP2B protein levels relative to vehicle control animals. However, hepatic CYP2B protein in animals co-exposed to PCB 95 and nicotine were reduced compared to animals that received only nicotine. Quantification of CYP2B3, CYP3A2 and CYP1A2 mRNA identified significant effects of nicotine and PCB 95 co-exposure on hepatic CYP3A2 and hippocampal CYP1A2 transcripts. Our findings suggest that nicotine co-exposure does not significantly influence PCB 95 disposition in the rat. However, these studies suggest a novel influence of PCB 95 and nicotine co-exposure on hepatic cytochrome P450 (P450) expression that may warrant further attention due to the increasing use of e-cigarettes and related products.
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42
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Kania-Korwel I, Barnhart CD, Lein PJ, Lehmler HJ. Effect of pregnancy on the disposition of 2,2',3,5',6-pentachlorobiphenyl (PCB 95) atropisomers and their hydroxylated metabolites in female mice. Chem Res Toxicol 2015; 28:1774-83. [PMID: 26271003 DOI: 10.1021/acs.chemrestox.5b00241] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chiral PCBs, such as PCB 95, are developmental neurotoxicants that undergo atropisomeric enrichment in nonpregnant adult mice. Because pregnancy is associated with changes in hepatic cytochrome P450 enzyme activity as well as lipid disposition and metabolism, this study investigates the effect of pregnancy on the maternal disposition of chiral PCBs. Female C57BL/6 mice (8 weeks old) were dosed daily beginning 2 weeks prior to conception and continuing throughout gestation and lactation (56 days total) with racemic PCB 95 (0, 0.1, 1.0, or 6.0 mg/kg body wt/day) in peanut butter. Levels and chiral signatures of PCB 95 and its hydroxylated metabolites (OH-PCBs) were determined in adipose, blood, brain, and liver. Tissue levels of PCB 95 increased 4- to 12-fold with increasing dose, with considerable enrichment of the second eluting atropisomer in all tissues (EF range 0.11 to 0.26). OH-PCBs displayed atropisomeric enrichment in blood and liver but were not detected in adipose and brain. Levels of PCB 95 and its metabolites were 2- to 11-fold lower in pregnant dams relative to those previously reported in nonpregnant age-matched female mice; however, PCB 95 and OH-PCB profiles and chiral signatures were similar between both studies. In contrast, human brain samples contained racemic PCB 95 residues (EF = 0.50). These results demonstrate that changes in cytochrome P450 enzyme activity and lipid disposition during pregnancy reduce the PCB body burden in dams but do not affect metabolite profiles or chiral signatures. The differences in chiral signatures between mice and humans suggest species-specific differences in atropisomeric disposition, the toxicological significance of which remains to be determined.
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Affiliation(s)
- Izabela Kania-Korwel
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa , Iowa City, Iowa 52242-5000, United States
| | - Christopher D Barnhart
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California , Davis, California 95616, United States
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California , Davis, California 95616, United States
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa , Iowa City, Iowa 52242-5000, United States
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Wahlang B, Falkner KC, Cave MC, Prough RA. Role of Cytochrome P450 Monooxygenase in Carcinogen and Chemotherapeutic Drug Metabolism. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2015; 74:1-33. [PMID: 26233902 DOI: 10.1016/bs.apha.2015.04.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The purpose of this chapter is to provide insight into which human cytochromes P450 (CYPs) may be involved in metabolism of chemical carcinogens and anticancer drugs. A historical overview of this field and the development of literature using relevant animal models and expressed human CYPs have provided information about which specific CYPs may be involved in carcinogen metabolism. Definition of the biochemical properties of CYP activity came from several groups who studied the reaction stoichiometry of butter yellow and benzo[α]pyrene, including their role in induction of these enzyme systems. This chapter will list as much as is known about the human CYPs involved in carcinogen and anticancer drug metabolism, as well as summarize studies with rodent CYPs. A review of three major classes of anticancer drugs and their metabolism in humans is covered for cyclophosphamide, procarbazine, and anthracycline antibiotics, cancer chemotherapeutic compounds extensively metabolized by CYPs. The emerging information about human CYP gene polymorphisms as well as other enzymes involved in foreign compound metabolism provides considerable information about how these genetic variants affect carcinogen and anticancer drug metabolism. With information available from individual's genomic sequences, consideration of populations who may be at risk due to environmental exposure to carcinogens or how to optimize their cancer therapy regimens to enhance efficacy of the anticancer drugs appears to be an important field of study to benefit individuals in the future.
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Affiliation(s)
- B Wahlang
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, University of Louisville, Louisville, Kentucky, USA
| | - K Cameron Falkner
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, University of Louisville, Louisville, Kentucky, USA
| | - Matt C Cave
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, University of Louisville, Louisville, Kentucky, USA; Department of Biochemistry & Molecular Biology, University of Louisville, Louisville, Kentucky, USA
| | - Russell A Prough
- Department of Biochemistry & Molecular Biology, University of Louisville, Louisville, Kentucky, USA.
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44
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Grimm FA, Hu D, Kania-Korwel I, Lehmler HJ, Ludewig G, Hornbuckle KC, Duffel MW, Bergman A, Robertson LW. Metabolism and metabolites of polychlorinated biphenyls. Crit Rev Toxicol 2015; 45:245-72. [PMID: 25629923 PMCID: PMC4383295 DOI: 10.3109/10408444.2014.999365] [Citation(s) in RCA: 276] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 12/11/2014] [Indexed: 11/13/2022]
Abstract
Abstract The metabolism of polychlorinated biphenyls (PCBs) is complex and has an impact on toxicity, and thereby on the assessment of PCB risks. A large number of reactive and stable metabolites are formed in the processes of biotransformation in biota in general, and in humans in particular. The aim of this document is to provide an overview of PCB metabolism, and to identify the metabolites of concern and their occurrence. Emphasis is given to mammalian metabolism of PCBs and their hydroxyl, methylsulfonyl, and sulfated metabolites, especially those that persist in human blood. Potential intracellular targets and health risks are also discussed.
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Affiliation(s)
- FA Grimm
- Interdisciplinary Graduate Program in Human Toxicology, Department of Pharmaceutical Sciences & Experimental Therapeutics, University of Iowa
| | - D Hu
- Department of Civil and Environmental Engineering, University of Iowa
| | - I Kania-Korwel
- Department of Occupational & Environmental Health, University of Iowa
| | - HJ Lehmler
- Interdisciplinary Graduate Program in Human Toxicology, Department of Occupational & Environmental Health, University of Iowa
| | - G Ludewig
- Interdisciplinary Graduate Program in Human Toxicology, Department of Occupational & Environmental Health, University of Iowa
| | - KC Hornbuckle
- Interdisciplinary Graduate Program in Human Toxicology, Department of Civil and Environmental Engineering, University of Iowa
| | - MW Duffel
- Interdisciplinary Graduate Program in Human Toxicology, Department of Pharmaceutical Sciences & Experimental Therapeutics, University of Iowa
| | - A Bergman
- Swedish Toxicology Sciences Research Center (SWETOX), Forskargatan 20, SE-151 36 Södertälje, SWEDEN
| | - LW Robertson
- Interdisciplinary Graduate Program in Human Toxicology, Department of Occupational & Environmental Health, University of Iowa
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45
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Zheng XB, Luo XJ, Zeng YH, Wu JP, Mai BX. Chiral polychlorinated biphenyls (PCBs) in bioaccumulation, maternal transfer, and embryo development of chicken. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:785-791. [PMID: 25525742 DOI: 10.1021/es503748w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Polychlorinated biphenyls (PCBs) and enantiomer fractions (EFs) of PCB enantiomers (PCBs 95, 132, 135, and 149) were investigated in soil and chicken feed, chicken (Gallus domesticus) tissues, eggs on 0, 7, and 14 days after the onset of incubation, and newborn chick tissues. The EF values of PCBs 95, 132, and 149 changed significantly from soil to chicken tissues, and the values in the liver exhibited the highest deviation from the racemic ratio, indicating enantiomer-selective metabolism in hens. Congeners, which are highly resistant to degradation, such as PCBs 138, 153, and 180, exhibited the highest maternal transfer potentials when muscle and liver were used to assess the maternal transfer. However, uniform transfer ratios were observed for most of the PCB congeners when visceral fat was used. The EFs of chiral PCBs in eggs either did not match with muscle or with liver or were similar to those in visceral fat. These results indicate that hens mainly mobilized visceral fat for egg formation and PCBs were deposited in eggs by associating with these lipid materials. Further enantiomeric enrichment of PCBs 95, 132, and 149 occurred in the newborn chick tissues. However, an opposite enantioselectivity for PCB 135 in newborn chicks was observed. These results indicate that the potential toxicity of PCB enantiomers to newborn chicks may be different from that of adults.
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46
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Wu X, Barnhart C, Lein P, Lehmler HJ. Hepatic metabolism affects the atropselective disposition of 2,2',3,3',6,6'-hexachlorobiphenyl (PCB 136) in mice. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:616-25. [PMID: 25420130 PMCID: PMC4291784 DOI: 10.1021/es504766p] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
To understand the role of hepatic vs extrahepatic metabolism in the disposition of chiral PCBs, we studied the disposition of 2,2',3,3',6,6'-hexachlorobiphenyl (PCB 136) and its hydroxylated metabolites (HO-PCBs) in mice with defective hepatic metabolism due to the liver-specific deletion of cytochrome P450 oxidoreductase (KO mice). Female KO and congenic wild type (WT) mice were treated with racemic PCB 136, and levels and chiral signatures of PCB 136 and HO-PCBs were determined in tissues and excreta 3 days after PCB administration. PCB 136 tissue levels were higher in KO compared to WT mice. Feces was a major route of PCB metabolite excretion, with 2,2',3,3',6,6'-hexachlorobiphenyl-5-ol being the major metabolite recovered from feces. (+)-PCB 136, the second eluting PCB 136 atropisomers, was enriched in all tissues and excreta. The second eluting atropisomers of the HO-PCBs metabolites were enriched in blood and liver; 2,2',3,3',6,6'-hexachlorobiphenyl-5-ol in blood was an exception and displayed an enrichment of the first eluting atropisomers. Fecal HO-PCB levels and chiral signatures changed with time and differed between KO and WT mice, with larger HO-PCB enantiomeric fractions in WT compared to KO mice. Our results demonstrate that hepatic and, possibly, extrahepatic cytochrome P450 (P450) enzymes play a role in the disposition of PCBs.
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Affiliation(s)
- Xianai Wu
- Department
of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Christopher Barnhart
- Department
of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616, United States
| | - Pamela
J. Lein
- Department
of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616, United States
| | - Hans-Joachim Lehmler
- Department
of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa 52242, United States
- Phone: 319 335-4310. Fax: 319 335-4290. E-mail: . Corresponding author address:
Department of Occupational and Environmental
Health, The University of Iowa, University of Iowa Research Park,
#221 IREH, Iowa City, IA 52242-5000
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47
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Chen H, Zou Y, Zhang L, Wen Y, Liu W. Enantioselective toxicities of chiral ionic liquids 1-alkyl-3-methylimidazolium lactate to aquatic algae. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 154:114-20. [PMID: 24880783 DOI: 10.1016/j.aquatox.2014.05.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 05/09/2014] [Accepted: 05/11/2014] [Indexed: 05/19/2023]
Abstract
With the wide application of chiral ionic liquids (CILs) as green solvents, their threats to the aquatic environment cannot be ignored. Thus, risk assessment and the prospective design of inherently safe CILs have become more urgent. However, whether enantioselectivity is a feature of the aquatic toxicity of CILs is poorly understood. Herein, we describe the first investigation into the ecotoxicities of CILs toward green algae Scenedesmus obliquus and Euglena gracilis. A series of methylimidazolium lactic ionic liquids, which cation parts with different alkyl chains and anion part is enantiomers of lactate, are used as representative CILs. The results of S. obliquus showed that the EC50 value of L-(+)-1-ethyl-3-methylimidazolium lactate (L-(+)-EMIM L) was more than 5000 μM, while the EC50 value of D-(-)-1-ethyl-3-methylimidazolium lactate (D-(-)-EMIM L) was 2255.21 μM. Such a distinct difference indicates the enantioselective toxicity of CILs to algae. This enantioselectivity initially persisted with increasing carbon chain length, but no longer exhibited when with greater carbon chain lengths, due to changes in the toxicity weightings of the cation parts. Further research showed that the enantioselective effects of CILs resulted from the differences in the production of reactive oxygen species, the damage to cell membrane integrity and cell wall after exposure to CILs. Results from this study showed that monitoring for the racemate CILs will give an inadequate or misleading environmental risk assessment. Thus, we should improve our ability to predict their effects in natural environments. In the meantime, non-selective use of CILs will do harm to aquatic organisms. Therefore, to minimize their potential for environmental impact, the enantioselective toxicities of CILs with short alkyl chains should be taken into consideration.
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Affiliation(s)
- Hui Chen
- Institute of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Yuqin Zou
- Institute of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Lijuan Zhang
- MOE Key Laboratory of Environmental Remediation & Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yuezhong Wen
- Institute of Environmental Science, Zhejiang University, Hangzhou 310058, China.
| | - Weiping Liu
- MOE Key Laboratory of Environmental Remediation & Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
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48
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Chen SJ, Tian M, Zheng J, Zhu ZC, Luo Y, Luo XJ, Mai BX. Elevated levels of polychlorinated biphenyls in plants, air, and soils at an E-waste site in Southern China and enantioselective biotransformation of chiral PCBs in plants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:3847-3855. [PMID: 24628413 DOI: 10.1021/es405632v] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
E-waste that contains polychlorinated biphenyls (PCBs) is moved across national boundaries, often from industrialized countries in the northern hemisphere, where the items were formerly used, to subtropical and tropical regions in southeastern Asia and Africa. As a result, there is a high likelihood that PCBs will be released into the environment from a primary source due to the elevated temperatures encountered in these low-latitude regions. In the present study, PCBs and enantiomer fractions (EFs) of chiral PCBs (PCB 84, 95, 132, 136, 149, and 183) were analyzed in air, eucalyptus leaves, pine needles, and soil at an e-waste site and a rural site in southern China. The concentrations of PCBs at the e-waste site ranged from 7825 to 76330 pg/m(3), 27.5 to 1993 ng/g, and 24.2 to 12045 ng/g in the air (gas plus particle), plant leaves, and soils, respectively. The atmospheric PCB composition profiles in the present study indicated relatively high abundances of penta- and hexa-PCBs, which were different from those previously observed in the air across China. The Clausius-Clapeyron regression analysis indicated that evaporation from local contaminated surfaces constitutes a primary emission source of PCBs in the air at the e-waste site. The chiral signatures of PCBs in the air at the e-waste site were essentially racemic (mean EFs = (0.484 ± 0.022)-(0.499 ± 0.004) in the gaseous phase) except for PCB 84 (0.420 ± 0.050), indicating that racemic sources dominate the PCB emission in the air. PCB chiral signatures in the soils ((0.422 ± 0.038)-(0.515 ± 0.016)) were similar to those in the air except for PCB 95. However, the chiral PCBs in the plants (especially the eucalyptus leaves) had significantly nonracemic residues ((0.368 ± 0.075)-(0.561 ± 0.045)) compared to those in the air and soil. This finding suggests that enantioselective biotransformation of these atropisomeric PCBs was very likely to occur in the plant leaves, possibly due to metabolism by cytochrome P-450 enzymes in leaves. To our knowledge, this is the first report on the enantioselective metabolism of chiral PCBs in plants under field conditions.
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Affiliation(s)
- She-Jun Chen
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, China
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49
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Lu Z, Fisk AT, Kovacs KM, Lydersen C, McKinney MA, Tomy GT, Rosenburg B, McMeans BC, Muir DCG, Wong CS. Temporal and spatial variation in polychlorinated biphenyl chiral signatures of the Greenland shark (Somniosus microcephalus) and its arctic marine food web. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2014; 186:216-225. [PMID: 24389599 DOI: 10.1016/j.envpol.2013.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 12/02/2013] [Accepted: 12/05/2013] [Indexed: 06/03/2023]
Abstract
Polychlorinated biphenyls (PCBs) chiral signatures were measured in Greenland sharks (Somniosus microcephalus) and their potential prey in arctic marine food webs from Canada (Cumberland Sound) and Europe (Svalbard) to assess temporal and spatial variation in PCB contamination at the stereoisomer level. Marine mammals had species-specific enantiomer fractions (EFs), likely due to a combination of in vivo biotransformation and direct trophic transfer. Greenland sharks from Cumberland Sound in 2007-2008 had similar EFs to those sharks collected a decade ago in the same location (PCBs 91, 136 and 149) and also similar to their conspecifics from Svalbard for some PCB congeners (PCBs 95, 136 and 149). However, other PCB EFs in the sharks varied temporally (PCB 91) or spatially (PCB 95), suggesting a possible spatiotemporal variation in their diets, since biotransformation capacity was unlikely to have varied within this species from region to region or over the time frame studied.
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Affiliation(s)
- Zhe Lu
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Aaron T Fisk
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Kit M Kovacs
- Norwegian Polar Institute, Fram Centre, N-9296 Tromsø, Norway
| | | | - Melissa A McKinney
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Gregg T Tomy
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Bruno Rosenburg
- Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, MB R3T 2N6, Canada
| | - Bailey C McMeans
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Derek C G Muir
- Aquatic Contaminants Research Division, Environment Canada, Burlington, ON L7R 4A6, Canada
| | - Charles S Wong
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; Richardson College for the Environment, University of Winnipeg, Winnipeg, MB R3B 2E9, Canada.
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50
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Wu X, Kammerer A, Lehmler HJ. Microsomal oxidation of 2,2',3,3',6,6'-hexachlorobiphenyl (PCB 136) results in species-dependent chiral signatures of the hydroxylated metabolites. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:2436-44. [PMID: 24467194 PMCID: PMC3983324 DOI: 10.1021/es405433t] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 01/16/2014] [Accepted: 01/27/2014] [Indexed: 05/18/2023]
Abstract
Chiral polychlorinated biphenyls (PCBs) display variable atropisomeric enrichment in wildlife and animal models, especially at higher trophic levels. These differences in PCBs' chiral signatures are, at least in part, due to species-dependent oxidation of PCBs to hydroxylated PCB metabolites (OH-PCBs). Here, we investigate the hypothesis that the cytochrome P450 (P450) enzyme-mediated oxidation of chiral PCBs results in species-dependent differences in the chiral signatures of OH-PCBs (i.e., the direction and extent of OH-PCBs' atropisomeric enrichment). To investigate this hypothesis, we incubated PCB 136, a representative chiral PCB, with pooled human liver microsomes (HLMs) or liver microsomes from male guinea pig, hamster, monkey, mouse, and rabbit or female dog and determined average profiles and chiral signatures of the OH-PCBs. 2,2',3,3',6,6'-Hexachlorobiphenyl-4-ol (4-136) was the major metabolite in incubations with HLMs and monkey and rabbit microsomes. 2,2',3,3',6,6'-Hexachlorobiphenyl-5-ol (5-136) was the major metabolite formed by microsomes from all other species. Both 4-136 and 5-136 were formed atropselectively in all microsomal incubations; however, the direction and extent of the atropisomeric enrichment of both OH-PCB metabolites showed considerable differences across microsomal preparations obtained from different species. These differences in OH-PCBs' atropisomeric enrichment may not only be toxicologically relevant but may also be useful to study sources and transport of OH-PCBs in the environment.
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