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Bullert A, Li X, Gautam B, Wang H, Adamcakova-Dodd A, Wang K, Thorne PS, Lehmler HJ. Distribution of 2,2',5,5'-Tetrachlorobiphenyl (PCB52) Metabolites in Adolescent Rats after Acute Nose-Only Inhalation Exposure. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:6105-6116. [PMID: 38547313 PMCID: PMC11008251 DOI: 10.1021/acs.est.3c09527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 02/02/2024] [Accepted: 03/09/2024] [Indexed: 04/10/2024]
Abstract
Inhalation of PCB-contaminated air is increasingly recognized as a route for PCB exposure. Because limited information about the disposition of PCBs following inhalation exposure is available, this study investigated the disposition of 2,2',5,5'-tetrachlorobiphenyl (PCB52) and its metabolites in rats following acute, nose-only inhalation of PCB52. Male and female Sprague-Dawley rats (50-58 days of age, 210 ± 27 g; n = 6) were exposed for 4 h by inhalation to approximately 14 or 23 μg/kg body weight of PCB52 using a nose-only exposure system. Sham animals (n = 6) were exposed to filtered lab air. Based on gas chromatography-tandem mass spectrometry (GC-MS/MS), PCB52 was present in adipose, brain, intestinal content, lung, liver, and serum. 2,2',5,5'-Tetrachlorobiphenyl-4-ol (4-OH-PCB52) and one unknown monohydroxylated metabolite were detected in these compartments except for the brain. Liquid chromatography-high resolution mass spectrometry (LC-HRMS) analysis identified several metabolites, including sulfated, methoxylated, and dechlorinated PCB52 metabolites. These metabolites were primarily found in the liver (7 metabolites), lung (9 metabolites), and serum (9 metabolites) due to the short exposure time. These results demonstrate for the first time that complex mixtures of sulfated, methoxylated, and dechlorinated PCB52 metabolites are formed in adolescent rats following PCB52 inhalation, laying the groundwork for future animal studies of the adverse effects of inhaled PCB52.
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Affiliation(s)
- Amanda
J. Bullert
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
- Interdisciplinary
Graduate Program in Neuroscience, The University
of Iowa, Iowa City, Iowa 52242, United States
| | - Xueshu Li
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Binita Gautam
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Hui Wang
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Andrea Adamcakova-Dodd
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Kai Wang
- Department
of Biostatistics, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Peter S. Thorne
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
- Interdisciplinary
Graduate Program in Neuroscience, 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
- Interdisciplinary
Graduate Program in Neuroscience, The University
of Iowa, Iowa City, Iowa 52242, United States
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2
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Duffel MW, Lehmler HJ. Complex roles for sulfation in the toxicities of polychlorinated biphenyls. Crit Rev Toxicol 2024; 54:92-122. [PMID: 38363552 PMCID: PMC11067068 DOI: 10.1080/10408444.2024.2311270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 01/23/2024] [Indexed: 02/17/2024]
Abstract
Polychlorinated biphenyls (PCBs) are persistent organic toxicants derived from legacy pollution sources and their formation as inadvertent byproducts of some current manufacturing processes. Metabolism of PCBs is often a critical component in their toxicity, and relevant metabolic pathways usually include their initial oxidation to form hydroxylated polychlorinated biphenyls (OH-PCBs). Subsequent sulfation of OH-PCBs was originally thought to be primarily a means of detoxication; however, there is strong evidence that it may also contribute to toxicities associated with PCBs and OH-PCBs. These contributions include either the direct interaction of PCB sulfates with receptors or their serving as a localized precursor for OH-PCBs. The formation of PCB sulfates is catalyzed by cytosolic sulfotransferases, and, when transported into the serum, these metabolites may be retained, taken up by other tissues, and subjected to hydrolysis catalyzed by intracellular sulfatase(s) to regenerate OH-PCBs. Dynamic cycling between PCB sulfates and OH-PCBs may lead to further metabolic activation of the resulting OH-PCBs. Ultimate toxic endpoints of such processes may include endocrine disruption, neurotoxicities, and many others that are associated with exposures to PCBs and OH-PCBs. This review highlights the current understanding of the complex roles that PCB sulfates can have in the toxicities of PCBs and OH-PCBs and research on the varied mechanisms that control these roles.
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Affiliation(s)
- Michael W. Duffel
- Department of Pharmaceutical Sciences & Experimental Therapeutics, College of Pharmacy, The University of Iowa, Iowa City, Iowa, 52242, 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
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3
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Bullert A, Li X, Chunyun Z, Lee K, Pulliam CF, Cagle BS, Doorn JA, Klingelhutz AJ, Robertson LW, Lehmler HJ. Disposition and metabolomic effects of 2,2',5,5'-tetrachlorobiphenyl in female rats following intraperitoneal exposure. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2023; 102:104245. [PMID: 37572994 PMCID: PMC10562985 DOI: 10.1016/j.etap.2023.104245] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 08/07/2023] [Accepted: 08/09/2023] [Indexed: 08/14/2023]
Abstract
The disposition and toxicity of lower chlorinated PCBs (LC-PCBs) with less than five chlorine substituents have received little attention. This study characterizes the distribution and metabolomic effects of PCB 52, an LC-PCB found in indoor and outdoor air, three weeks after intraperitoneal exposure of female Sprague Dawley rats to 0, 1, 10, or 100 mg/kg BW. PCB 52 exposure did not affect overall body weight. Gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis identified PCB 52 in all tissues investigated. Hydroxylated, sulfated, and methylated PCB metabolites, identified using GC-MS/MS and nontarget liquid chromatography-high resolution mass spectrometry (Nt-LCMS), were primarily found in the serum and liver of rats exposed to 100 mg/kg BW. Metabolomic analysis revealed minor effects on L-cysteine, glycine, cytosine, sphingosine, thymine, linoleic acid, orotic acid, L-histidine, and erythrose serum levels. Thus, the metabolism of PCB 52 and its effects on the metabolome must be considered in toxicity studies.
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Affiliation(s)
- Amanda Bullert
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, USA; Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, USA
| | - Xueshu Li
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | - Zhang Chunyun
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | - Kendra Lee
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | - Casey F Pulliam
- Interdisciplinary Graduate Program in Human Toxicology, University of Iowa, Iowa City, IA 52242, USA
| | - Brianna S Cagle
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, IA 52242, USA
| | - Jonathan A Doorn
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, USA; Interdisciplinary Graduate Program in Human Toxicology, University of Iowa, Iowa City, IA 52242, USA; Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, IA 52242, USA
| | - Aloysius J Klingelhutz
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Larry W Robertson
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, USA; Interdisciplinary Graduate Program in Human Toxicology, University of Iowa, Iowa City, IA 52242, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, USA; Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, USA; Interdisciplinary Graduate Program in Human Toxicology, University of Iowa, Iowa City, IA 52242, USA.
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4
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Bullert A, Li X, Zhang C, Lee K, Pulliam CF, Cagle BS, Doorn JA, Klingelhutz AJ, Robertson LW, Lehmler HJ. Disposition and Metabolomic Effects of 2,2',5,5'-Tetrachlorobiphenyl in Female Rats Following Intraperitoneal Exposure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.19.544952. [PMID: 37609242 PMCID: PMC10441371 DOI: 10.1101/2023.06.19.544952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The disposition and toxicity of lower chlorinated PCBs (LC-PCBs) with less than five chlorine substituents have received little attention. This study characterizes the distribution and metabolomic effects of PCB 52, an LC-PCB found in indoor and outdoor air, three weeks after intraperitoneal exposure of female Sprague Dawley rats to 0, 1, 10, or 100 mg/kg BW. PCB 52 exposure did not affect overall body weight. Gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis identified PCB 52 in all tissues investigated. Hydroxylated, sulfated, and methylated PCB metabolites, identified using GC-MS/MS and nontarget liquid chromatography-high resolution mass spectrometry (Nt-LCMS), were primarily found in the serum and liver of rats exposed to 100 mg/kg BW. Metabolomic analysis revealed minor effects on L-cysteine, glycine, cytosine, sphingosine, thymine, linoleic acid, orotic acid, L-histidine, and erythrose serum levels. Thus, the metabolism of PCB 52 and its effects on the metabolome must be considered in toxicity studies. Highlights PCB 52 was present in adipose, brain, liver, and serum 3 weeks after PCB exposureLiver and serum contained hydroxylated, sulfated, and methylated PCB 52 metabolitesMetabolomics analysis revealed minor changes in endogenous serum metabolitesLevels of dopamine and its metabolites in the brain were not affected by PCB 52.
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Affiliation(s)
- Amanda Bullert
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, USA
| | - Xueshu Li
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | - Chunyun Zhang
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | - Kendra Lee
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | - Casey F. Pulliam
- Interdisciplinary Program in Human Toxicology, University of Iowa, Iowa City, IA 52242, USA
| | - Brianna S. Cagle
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, IA 52242, USA
| | - Jonathan A. Doorn
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Program in Human Toxicology, University of Iowa, Iowa City, IA 52242, USA
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, IA 52242, USA
| | - Aloysius J. Klingelhutz
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Larry W. Robertson
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Program in Human Toxicology, University of Iowa, Iowa City, IA 52242, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Program in Human Toxicology, University of Iowa, Iowa City, IA 52242, USA
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Saktrakulkla P, Li X, Martinez A, Lehmler HJ, Hornbuckle KC. Hydroxylated Polychlorinated Biphenyls Are Emerging Legacy Pollutants in Contaminated Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:2269-2278. [PMID: 35107261 PMCID: PMC8851693 DOI: 10.1021/acs.est.1c04780] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 01/22/2022] [Accepted: 01/24/2022] [Indexed: 05/04/2023]
Abstract
We measured the concentrations of 837 hydroxylated polychlorinated biphenyls (OH-PCBs, in 275 chromatographic peaks) and 209 polychlorinated biphenyls (PCBs, in 174 chromatographic peaks) in sediments from New Bedford Harbor in Massachusetts, Altavista wastewater lagoon in Virginia, and the Indiana Harbor and Ship Canal in Indiana, USA and in the original commercial PCB mixtures Aroclors 1016, 1242, 1248, and 1254. We used the correlation between homologues and the peak responses to quantify the full suite of OH-PCBs including those without authentic standards available. We found that OH-PCB levels are approximately 0.4% of the PCB levels in sediments and less than 0.0025% in Aroclors. The OH-PCB congener distributions of sediments are different from those of Aroclors and are different according to sites. We also identified a previously unknown compound, 4-OH-PCB52, which together with 4'-OH-PCB18 made up almost 30% of the OH-PCBs in New Bedford Harbor sediments but less than 1.2% in the Aroclors and 3.3% in any other sediments. This indicates site-specific environmental transformations of PCBs to OH-PCBs. We conclude that the majority of OH-PCBs in these sediments are generated in the environment. Our findings suggest that these toxic breakdown products of PCBs are prevalent in PCB-contaminated sediments and present an emerging concern for humans and ecosystems.
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Affiliation(s)
- Panithi Saktrakulkla
- Interdisciplinary
Graduate Program in Human Toxicology, The
University of Iowa, Iowa City, Iowa 52242, United States
- Department
of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Xueshu Li
- Department
of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Andres Martinez
- Department
of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Hans-Joachim Lehmler
- Interdisciplinary
Graduate Program in Human Toxicology, The
University of Iowa, Iowa City, Iowa 52242, United States
- Department
of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Keri C. Hornbuckle
- Interdisciplinary
Graduate Program in Human Toxicology, The
University of Iowa, Iowa City, Iowa 52242, United States
- Department
of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, Iowa 52242, United States
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6
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Zhang D, Saktrakulkla P, Tuttle K, Marek RF, Lehmler HJ, Wang K, Hornbuckle KC, Duffel MW. Detection and Quantification of Polychlorinated Biphenyl Sulfates in Human Serum. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:2473-2481. [PMID: 33502843 PMCID: PMC7924310 DOI: 10.1021/acs.est.0c06983] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Polychlorinated biphenyls (PCBs) are persistent toxic chemicals with both legacy sources (e.g., Aroclors) and new sources (e.g., unintentional contaminants in some pigments and varnishes). PCB sulfates are derived from further metabolism of hydroxylated PCBs (OH-PCBs), which are oxidative metabolites of PCBs. While OH-PCBs and PCB sulfates are implicated in multiple toxicological effects, studies of PCB sulfates in human serum have been limited by available analytical procedures. We have now developed a method for extraction of PCB sulfates from serum followed by differential analysis with, and without, sulfatase-catalyzed hydrolysis to OH-PCBs. A sulfatase from Helix pomatia was purified by affinity chromatography, and it displayed broad specificity for PCB sulfates without contaminant glucuronidase activity. Following sulfatase-catalyzed hydrolysis of the PCB sulfates extracted from serum, the corresponding OH-PCBs were derivatized to methoxy-PCBs and quantitated by GC-MS/MS. In a pooled sample of human serum, we identified 10 PCB sulfates, with three PCB sulfate congeners exhibiting the highest concentrations from 1200 to 3970 pg/g of serum. In conclusion, we have developed a sensitive and specific method for the determination of PCB sulfates in human serum.
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Affiliation(s)
- Duo Zhang
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA 52242
- Department of Pharmaceutical Sciences & Experimental Therapeutics, The University of Iowa, Iowa City, IA 52242
| | - Panithi Saktrakulkla
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA 52242
- Department of Civil and Environmental Engineering, The University of Iowa, Iowa City, IA 52242
| | - Kristopher Tuttle
- Department of Pharmaceutical Sciences & Experimental Therapeutics, The University of Iowa, Iowa City, IA 52242
| | - Rachel F. Marek
- Department of Civil and Environmental Engineering, The University of Iowa, Iowa City, IA 52242
- IIHR-Hydroscience & Engineering, The University of Iowa, Iowa City, IA 52242
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA 52242
| | - Kai Wang
- Department of Biostatistics, The University of Iowa, Iowa City, IA 52242
| | - Keri C. Hornbuckle
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA 52242
- Department of Civil and Environmental Engineering, The University of Iowa, Iowa City, IA 52242
- IIHR-Hydroscience & Engineering, The University of Iowa, Iowa City, IA 52242
| | - Michael W. Duffel
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA 52242
- Department of Pharmaceutical Sciences & Experimental Therapeutics, The University of Iowa, Iowa City, IA 52242
- Corresponding Author:
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7
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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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Grimm FA, Klaren WD, Li X, Lehmler HJ, Karmakar M, Robertson LW, Chiu WA, Rusyn I. Cardiovascular Effects of Polychlorinated Biphenyls and Their Major Metabolites. ENVIRONMENTAL HEALTH PERSPECTIVES 2020; 128:77008. [PMID: 32701041 PMCID: PMC7377239 DOI: 10.1289/ehp7030] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
BACKGROUND Xenobiotic metabolism is complex, and accounting for bioactivation and detoxification processes of chemicals remains among the most challenging aspects for decision making with in vitro new approach methods data. OBJECTIVES Considering the physiological relevance of human organotypic culture models and their utility for high-throughput screening, we hypothesized that multidimensional chemical-biological profiling of chemicals and their major metabolites is a sensible alternative for the toxicological characterization of parent molecules vs. metabolites in vitro. METHODS In this study, we tested 25 polychlorinated biphenyls (PCBs) [PCB 3, 11, 52, 126, 136, and 153 and their relevant metabolites (hydroxylated, methoxylated, sulfated, and quinone)] in concentration-response (10 nM-100μM) for effects in human induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CMs) and endothelial cells (ECs) (iPSC-derived and HUVECs). Functional phenotypic end points included effects on beating parameters and intracellular Ca2+ flux in CMs and inhibition of tubulogenesis in ECs. High-content imaging was used to evaluate cytotoxicity, mitochondrial integrity, and oxidative stress. RESULTS Data integration of a total of 19 physicochemical descriptors and 36 in vitro phenotypes revealed that chlorination status and metabolite class are strong predictors of the in vitro cardiovascular effects of PCBs. Oxidation of PCBs, especially to di-hydroxylated and quinone metabolites, was associated with the most pronounced effects, whereas sulfation and methoxylation of PCBs resulted in diminished bioactivity. DISCUSSION Risk characterization analysis showed that although in vitro derived effective concentrations exceeded the levels measured in the general population, risks cannot be ruled out due to the potential for population variability in susceptibility and the need to fill data gaps using read-across approaches. This study demonstrated a strategy for how in vitro data can be used to characterize human health risks from PCBs and their metabolites. https://doi.org/10.1289/EHP7030.
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Affiliation(s)
- Fabian A. Grimm
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - William D. Klaren
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Xueshu Li
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa, USA
| | - Moumita Karmakar
- Department of Statistics, College of Science, Texas A&M University, College Station, Texas, USA
| | - Larry W. Robertson
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa, USA
| | - Weihsueh A. Chiu
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Ivan Rusyn
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
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Egusquiza RJ, Ambrosio ME, Wang SG, Kay KM, Zhang C, Lehmler HJ, Blumberg B. Evaluating the Role of the Steroid and Xenobiotic Receptor (SXR/PXR) in PCB-153 Metabolism and Protection against Associated Adverse Effects during Perinatal and Chronic Exposure in Mice. ENVIRONMENTAL HEALTH PERSPECTIVES 2020; 128:47011. [PMID: 32352317 PMCID: PMC7228131 DOI: 10.1289/ehp6262] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 03/20/2020] [Accepted: 03/24/2020] [Indexed: 06/02/2023]
Abstract
BACKGROUND Polychlorinated biphenyls (PCBs) are environmental toxicants; PCB exposure has been associated with adverse effects on wildlife and humans. However, the mechanisms underlying these adverse effects are not fully understood. The steroid and xenobiotic receptor [SXR; also known as the pregnane X receptor (PXR) and formally known as NR1I2] is a nuclear hormone receptor that regulates inducible metabolism of drugs and xenobiotics and is activated or inhibited by various PCB congeners. OBJECTIVES The aim of this study was to investigate the effects of exposure to PCB-153, the most prevalent PCB congener in human tissues, on SXR knockout mice (SXRKO) and to elucidate the role of SXR in PCB-153 metabolism and promotion of its harmful effects. METHODS Wild-type (WT) and SXRKO mice were chronically or perinatally exposed to a low dose (54μg/kg/d) of PCB-153. Blood, livers, and spleens were analyzed using transcriptome sequencing (RNA-seq) and molecular techniques to investigate the impacts of exposure on metabolism, oxidative stress, and hematological parameters. RESULTS SXRKO mice perinatally exposed to PCB-153 displayed elevated oxidative stress, symptoms of hemolytic anemia, and premature death. Transcriptomal analysis revealed that expression of genes involved in metabolic processes was altered in SXRKO mice. Elevated levels of the PCB-153 metabolite, 3-OH-PCB-153, were found in exposed SXRKO mice compared to exposed WT mice. Blood hemoglobin (HGB) levels were lower throughout the lifespan, and the occurrence of intestinal tumors was larger in SXRKO mice chronically exposed to PCB-153 compared to vehicle and WT controls. DISCUSSION Our results suggest that altered metabolism induced by SXR loss of function resulted in the accumulation of hydroxylated metabolites upon exposure to PCB-153, leading to oxidative stress, hemolytic anemia, and tumor development in a mouse model. These results support a major role for SXR/PXR in protection against xenobiotic-induced oxidative stress by maintaining proper metabolism in response to PCB-153 exposure. This role of SXR could be generally applicable to other environmental toxicants as well as pharmaceutical drugs. https://doi.org/10.1289/EHP6262.
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Affiliation(s)
- Riann Jenay Egusquiza
- Department of Pharmaceutical Sciences, University of California, Irvine, California, USA
| | - Maria Elena Ambrosio
- Department of Developmental and Cell Biology, University of California, Irvine, California, USA
| | - Shuyi Gin Wang
- Department of Developmental and Cell Biology, University of California, Irvine, California, USA
| | - Kaelen Marie Kay
- Department of Developmental and Cell Biology, University of California, Irvine, California, USA
| | - Chunyun Zhang
- Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa, USA
| | - Bruce Blumberg
- Department of Pharmaceutical Sciences, University of California, Irvine, California, USA
- Department of Developmental and Cell Biology, University of California, Irvine, California, USA
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10
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Li SN, Cao YF, Sun XY, Yang K, Liang YJ, Gao SS, Fu ZW, Liu YZ, Yang K, Fang ZZ. Hydroxy metabolites of polychlorinated biphenyls (OH-PCBs) exhibit inhibitory effects on UDP-glucuronosyltransferases (UGTs). CHEMOSPHERE 2018; 212:513-522. [PMID: 30165278 DOI: 10.1016/j.chemosphere.2018.08.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 08/06/2018] [Accepted: 08/08/2018] [Indexed: 06/08/2023]
Abstract
Hydroxy metabolites of polychlorinated biphenyls (OH-PCBs) are important substance basis for the toxicity of PCBs. This study aims to investigate the inhibition of OH-PCBs on the activity of UDP-glucuronosyltransferases (UGTs), trying to elucidate the toxicity mechanism of PCBs from a new perspective. In vitrohuman recombinant UGTs-catalyzed glucuronidation of 4-methylumbelliferone (4-MU) was used as the probe reaction. The number of chlorine atom can affect the inhibition potential of OH-PCBs towards different isoforms of UGTs, and complex structure-activity relationship was found for the inhibition of OH-PCBs on the activities of UGT isoforms. For the inhibition kinetic determination, 2'OHPCB106 and 4'OHPCB106 were selected as the representative OH-PCBs, and UGT1A1, 1A7, and 2B7 were chosen as the representative UGT isoforms. Competitive inhibition of 2'OHPCB106 and 4'OHPCB106 on the activities of UGT1A1, UGT1A7, and UGT2B7 was found. For 2'OHPCB106, the inhibition kinetic parameters (Ki) were calculated to be 0.4 μM for UGT1A1, 1.3 μM for UGT1A7, and 2.7 μM for UGT2B7, respectively. For 4'OHPCB106, Ki values were calculated to be 0.7 μM for UGT1A1, 6.8 μM for UGT1A7, and 4.8 μM for UGT2B7, respectively. In silico docking method was utilized to elucidate the inhibition difference of UGT1A1 by four OH-PCBs with similar structures (4'OHPCB9, 4'OHPCB26, 4'OHPCB112 and 4'OHPCB165). In conclusion, these data will be helpful for understanding the toxicity mechanisms of PCBs from a view of metabolic interference.
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Affiliation(s)
- Sai-Nan Li
- Department of Toxicology, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China
| | - Yun-Feng Cao
- Key Laboratory of Contraceptives and Devices Research (NPFPC), Shanghai Engineer and Technology Research Center of Reproductive Health Drug and Devices, Shanghai Institute of Planned Parenthood Research, Shanghai, China; Key Laboratory of Liaoning Tumor Clinical Metabolomics (KLLTCM), Jinzhou, Liaoning, China
| | | | - Kai Yang
- Department of Toxicology, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China
| | - Ying-Jie Liang
- General Hospital of Liaohe Oil Field for China Petroleum, China
| | - Shi-Shuang Gao
- General Hospital of Liaohe Oil Field for China Petroleum, China
| | - Zhi-Wei Fu
- Department of Toxicology, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China
| | - Yong-Zhe Liu
- Department of Toxicology, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China
| | - Kun Yang
- Department of Toxicology, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China.
| | - Zhong-Ze Fang
- Department of Toxicology, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China.
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11
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Ma S, Ren G, Zeng X, Yu Z, Sheng G, Fu J. Polychlorinated biphenyls and their hydroxylated metabolites in the serum of e-waste dismantling workers from eastern China. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2018; 40:1931-1940. [PMID: 28477162 DOI: 10.1007/s10653-017-9958-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 04/18/2017] [Indexed: 05/16/2023]
Abstract
A number of studies have reported on the exposure of e-waste dismantling workers to significantly high concentrations of halogenated organic pollutants such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers. Such exposure can have adverse health effects. However, little information on the metabolites of these contaminants exists. In this study, we investigated PCBs levels and their hydroxylated metabolites (OH-PCB) in the serum of e-waste workers in Taizhou in eastern China. Our results indicate elevated PCB and OH-PCB levels in the serum of the workers, with medians of 443.7 and 133.9 ng/g lw, respectively. Tri- to hexachlorinated PCB congeners were the dominant homologue groups in all of the samples. 4-OH-CB107 was the predominant homologue among the hydroxylated metabolites, accounting for 88.9% of the total OH-PCB concentrations. While dietary sources (e.g., fish) appear to be an important route for PCB accumulation in non-occupational exposure groups, exposure via ingestion of house dust and inhalation of pollutants derived from the recycling of PCB-containing e-wastes may primarily contribute to the high body burden observed in the occupational groups. Since we found concentrations of metabolites higher than those of their parent compounds, further studies need to pay more attention to their bioaccumulation and toxicity.
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Affiliation(s)
- Shengtao Ma
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environment Protection and Resource Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Guofa Ren
- Institute of Environmental Pollution and Health, School of Environment and Chemical Engineering, Shanghai University, Shanghai, 200072, China
| | - Xiangying Zeng
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environment Protection and Resource Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Zhiqiang Yu
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environment Protection and Resource Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China.
| | - Guoying Sheng
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environment Protection and Resource Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Jiamo Fu
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environment Protection and Resource Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
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12
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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: 48] [Impact Index Per Article: 8.0] [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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13
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Liu Y, Hu K, Jia H, Jin G, Glatt H, Jiang H. Potent mutagenicity of some non-planar tri- and tetrachlorinated biphenyls in mammalian cells, human CYP2E1 being a major activating enzyme. Arch Toxicol 2016; 91:2663-2676. [DOI: 10.1007/s00204-016-1904-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 11/24/2016] [Indexed: 12/18/2022]
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14
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Flor S, He X, Lehmler HJ, Ludewig G. Estrogenicity and androgenicity screening of PCB sulfate monoesters in human breast cancer MCF-7 cells. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:2186-200. [PMID: 26300354 PMCID: PMC4718780 DOI: 10.1007/s11356-015-5142-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 08/03/2015] [Indexed: 04/15/2023]
Abstract
Recent studies identified polychlorinated biphenyl (PCB) sulfate esters as a major product of PCB metabolism. Since hydroxy-PCBs (HO-PCBs), the immediate precursors of PCB sulfates and important contributors to PCB toxicity, were shown to have estrogenic activity, we investigated the estrogenicity/androgenicty of a series of PCB sulfate metabolites. We synthesized the five possible structural sulfate monoester metabolites of PCB 3, a congener shown to be biotransformed to sulfates, a sulfate ester of the paint-specific congener PCB 11, and sulfate monoesters of two HO-PCBs reported to interact with sulfotransferases (PCB 39, no ortho chlorines, and PCB 53, 3 ortho chlorines). We tested these PCB sulfates and 4'-HO-PCB 3 as positive control for estrogenic, androgenic, anti-estrogenic, and anti-androgenic activity in the E- and A-screen with human breast cancer MCF7-derived cells at 100 μM-1 pM concentrations. Only 4'-HO-PCB 3 was highly cytotoxic at 100 μM. We observed structure-activity relationships: compounds with a sulfate group in the chlorine-containing ring of PCB 3 (2PCB 3 and 3PCB 3 sulfate) showed no interaction with the estrogen (ER) and androgen (AR) receptor. The 4'-HO-PCB 3 and its sulfate ester had the highest estrogenic effect, but at 100-fold different concentrations, i.e., 1 and 100 μM, respectively. Four of the PCB sulfates were estrogenic (2'PCB 3, 4'PCB 3, 4'PCB 39, and 4'PCB 53 sulfates; at 100 μM). These sulfates and 3'PCB 3 sulfate also exhibited anti-estrogenic activity, but at nM and pM concentrations. The 4'PCB 3 sulfate (para-para' substituted) had the strongest androgenic activity, followed by 3'PCB 3, 4'PCB 53, 4PCB11, and 4PCB 39 sulfates and the 4'HO-PCB 3. In contrast, anti-androgenicity was only observed with the two compounds that have the sulfate group in ortho- or meta- position in the second ring (2'PCB 3 and 3'PCB 3 sulfate). No dose-response was observed in any screen, but, with exception of estrogenic activity (only seen at 100 μM), endocrine activity was often displayed at several concentrations and even at 1 pM concentration. These data suggest that sulfation of HO-PCBs is indeed reducing their cytotoxicity and estrogenicity, but may produce other endocrine disruptive activities at very low concentrations.
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Affiliation(s)
- Susanne Flor
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus, 214 IREH, Iowa City, IA, 52242-5000, USA
| | - Xianran He
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus, 214 IREH, Iowa City, IA, 52242-5000, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus, 214 IREH, Iowa City, IA, 52242-5000, USA
| | - Gabriele Ludewig
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus, 214 IREH, Iowa City, IA, 52242-5000, USA.
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15
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Zhang C, Lai Y, Jin G, Glatt H, Wei Q, Liu Y. Human CYP2E1-dependent mutagenicity of mono- and dichlorobiphenyls in Chinese hamster (V79)-derived cells. CHEMOSPHERE 2016; 144:1908-1915. [PMID: 26547025 DOI: 10.1016/j.chemosphere.2015.10.083] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 10/19/2015] [Accepted: 10/20/2015] [Indexed: 06/05/2023]
Abstract
Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants with confirmed carcinogenicity to humans. Metabolic activation of lower chlorinated PCBs to genotoxic metabolites may involve hydroxylation and further oxidation, and some hydroxylated metabolites may be sulfo-conjugated. However, the genotoxicity of individual PCB compounds is largely unknown. In this study, 15 mono- and dichlorobiphenyls were investigated for genotoxicity using the micronucleus and Hprt mutagenicity assays in a Chinese hamster V79-derived cell line expressing both human cytochrome P450 (CYP) 2E1 and human sulfotransferase (SULT) 1A1 (V79-hCYP2E1-hSULT1A1). All tested compounds were inactive in both assays in V79 control cells. However, eight dichlorobiphenyls strongly induced micronuclei and other congeners were weakly positive for this endpoint in V79-hCYP2E1-hSULT1A1 cells. The effects of each PCB in V79-hCYP2E1-hSULT1A1 cells were abolished or reduced in the presence of a CYP2E1 inhibitor (1-aminobenzotriazole), or enhanced by pretreatment of the cells with (CYP2E1-inducing) ethanol, while the genotoxicity was not significantly affected by a SULT1 inhibitor (pentachlorophenol). As representative dichlorobiphenyls, PCB 5, 10, 8 and 11 (2,3-, 2,5-, 2,4'- and 3,3'-dichlorobiphenyl, respectively) strongly induced Hprt gene mutations in V79-hCYP2E1-hSULT1A1 cells in a concentration-dependent manner. This is the first indication that human CYP2E1 is capable of converting a series of dichlorobiphenyls to strong mutagens.
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Affiliation(s)
- Chiteng Zhang
- Department of Toxicology, School of Public Health and Tropical Medicine, Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Yanmei Lai
- Department of Toxicology, School of Public Health and Tropical Medicine, Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Guifang Jin
- Department of Toxicology, School of Public Health and Tropical Medicine, Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Hansruedi Glatt
- Department of Nutritional Toxicology, German Institute of Human Nutrition (DIfE), Arthur-Scheunert- Allee 114-116, D-14558 Nuthetal, Germany; Department of Food Safety, Federal Institute for Risk Assessment (BfR), Max-Hohrn-Straße 8-10, D-10589 Berlin, Germany
| | - Qinzhi Wei
- Department of Toxicology, School of Public Health and Tropical Medicine, Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Yungang Liu
- Department of Toxicology, School of Public Health and Tropical Medicine, Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China.
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16
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Ekuase EJ, van 't Erve TJ, Rahaman A, Robertson LW, Duffel MW, Luthe G. Mechanistic insights into the specificity of human cytosolic sulfotransferase 2A1 (hSULT2A1) for hydroxylated polychlorinated biphenyls through the use of fluoro-tagged probes. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:2119-2127. [PMID: 26165989 PMCID: PMC4713379 DOI: 10.1007/s11356-015-4886-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 06/15/2015] [Indexed: 06/04/2023]
Abstract
Determining the relationships between the structures of substrates and inhibitors and their interactions with drug-metabolizing enzymes is of prime importance in predicting the toxic potential of new and legacy xenobiotics. Traditionally, quantitative structure activity relationship (QSAR) studies are performed with many distinct compounds. Based on the chemical properties of the tested compounds, complex relationships can be established so that models can be developed to predict toxicity of novel compounds. In this study, the use of fluorinated analogues as supplemental QSAR compounds was investigated. Substituting fluorine induces changes in electronic and steric properties of the substrate without substantially changing the chemical backbone of the substrate. In vitro assays were performed using purified human cytosolic sulfotransferase hSULT2A1 as a model enzyme. A mono-hydroxylated polychlorinated biphenyl (4-OH PCB 14) and its four possible mono-fluoro analogues were used as test compounds. Remarkable similarities were found between this approach and previously published QSAR studies for hSULT2A1. Both studies implicate the importance of dipole moment and dihedral angle as being important to PCB structure in respect to being substrates for hSULT2A1. We conclude that mono-fluorinated analogues of a target substrate can be a useful tool to study the structure activity relationships for enzyme specificity.
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Affiliation(s)
- E J Ekuase
- Department of Pharmaceutical Sciences and Experimental Therapeutics, The University of Iowa, Iowa City, IA, USA
| | - T J van 't Erve
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA, USA.
- Institute of Life Sciences, Saxion University of Applied Sciences, Enschede, The Netherlands.
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA, USA.
- Immunity, Inflammation and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, 27709, NC, USA.
| | - A Rahaman
- Department of Chemistry, The University of Iowa, Iowa City, IA, USA
| | - L W Robertson
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA, USA
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA, USA
| | - M W Duffel
- Department of Pharmaceutical Sciences and Experimental Therapeutics, The University of Iowa, Iowa City, IA, USA
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA, USA
| | - G Luthe
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA, USA
- Institute of Life Sciences, Saxion University of Applied Sciences, Enschede, The Netherlands
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA, USA
- LuthePharma, Fabrikstrasse 2, 48599, Gronau, Germany
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17
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Grimm FA, He X, Teesch LM, Lehmler HJ, Robertson LW, Duffel MW. Tissue Distribution, Metabolism, and Excretion of 3,3'-Dichloro-4'-sulfooxy-biphenyl in the Rat. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:8087-95. [PMID: 26046945 PMCID: PMC4496304 DOI: 10.1021/acs.est.5b01499] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Polychlorinated biphenyls (PCBs) with less chlorine atoms exhibit a greater susceptibility to metabolism than their more-chlorinated counterparts. Following initial hydroxylation of these less-chlorinated PCBs, metabolic sulfation to form PCB sulfates is increasingly recognized as an important component of their toxicology. Because procedures for the quantitative analysis of PCB sulfates in tissue samples have not been previously available, we have now developed an efficient, LC-ESI-MS/MS-based protocol for the quantitative analysis of 4-PCB 11 sulfate in biological samples. This procedure was used to determine the distribution of 4-PCB 11 sulfate in liver, kidney, lung, and brain as well as its excretion profile following its intravenous administration to male Sprague-Dawley rats. Following initial uptake of 4-PCB 11 sulfate, its concentration in these tissues and serum declined within the first hour following injection. Although biliary secretion was detected, analysis of 24 h collections of urine and feces revealed recovery of less than 4% of the administered 4-PCB 11 sulfate. High-resolution LC-MS analysis of bile, urine, and feces showed metabolic products derived from 4-PCB 11 sulfate. Thus, 4-PCB 11 sulfate at this dose was not directly excreted in the urine but was instead redistributed to tissues and/or subjected to further metabolism.
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Affiliation(s)
- Fabian A. Grimm
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, Iowa, USA
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, The University of Iowa, Iowa City, Iowa, USA
| | - Xianran He
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, The University of Iowa, Iowa City, Iowa, USA
| | - Lynn M. Teesch
- High Resolution Mass Spectrometry Facility, The University of Iowa, Iowa City, USA
| | - Hans-Joachim Lehmler
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, Iowa, USA
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, The University of Iowa, Iowa City, Iowa, USA
| | - Larry W. Robertson
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, Iowa, USA
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, The University of Iowa, Iowa City, Iowa, USA
| | - Michael W. Duffel
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, Iowa, USA
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, The University of Iowa, Iowa City, Iowa, USA
- Address correspondence to Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, The University of Iowa, 115 South Grand Ave, S325, Iowa City, IA, 52246. Telephone: 319-335-8840. Fax: 319-335-8766.
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18
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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: 284] [Impact Index Per Article: 31.6] [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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19
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Zhai G, Gutowski SM, Lehmler HJ, Schnoor J. Enantioselective transport and biotransformation of chiral hydroxylated metabolites of polychlorinated biphenyls in whole poplar plants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:12213-20. [PMID: 25238141 PMCID: PMC4207536 DOI: 10.1021/es503443e] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs) have been found to be ubiquitous in the environment due to the oxidative metabolism of their parent PCBs. With more polarity, OH-PCBs may be more toxic and mobile than their parent compounds. However, the behavior and fate of OH-PCBs have been neglected in the environment because they are not the original contaminants. Some of these hydroxylated metabolites are chiral, and chiral compounds can be used to probe biological metabolic processes. Therefore, chiral OH-PCBs were selected to study their uptake, translocation, transformation, and enantioselectivity in plants in this work. Poplars (Populus deltoides × nigra, DN34), a model plant with complete genomic sequence, were hydroponically exposed to 5-hydroxy-2,2',3,4',6-pentachlorobiphenyl (5-OH-PCB91) and 5-hydroxy-2,2',3,5',6-pentachlorobiphenyl (5-OH-PCB95) for 10 days. Chiral 5-OH-PCB91 and 5-OH-PCB95 were clearly shown to be sorbed, taken up, and translocated in whole poplars, and they were detected in various tissues of whole poplars. However, the enantioselectivity of poplar for 5-OH-PCB91 and 5-OH-PCB95 proved to be quite different. The second-eluting enantiomer of OH-PCB95, separated on a chiral column (Phenomenex Lux Cellulose-1), was enantioselectively removed in whole poplar. Enantiomeric fractions in the middle xylem, top bark, top xylem, and stem, reached 0.803 ± 0.022, 0.643 ± 0.110, 0.835 ± 0.087, and 0.830 ± 0.029, respectively. Therefore, 5-OH-PCB95 was significantly enantioselectively biotransformed inside poplar tissues, in contrast to nearly racemic mixtures of 5-OH-PCB95 remaining in hydroponic solutions. Unlike 5-OH-PCB95, 5-OH-PCB91 remained nearly racemic in most tissues of whole poplars during 10 day exposure, suggesting the enantiomers of 5-OH-PCB91 were equally transported and metabolized in whole poplars. This is the first evidence of enantioselectivity of chiral OH-PCBs and suggests that poplars can enantioselectively biotransform at least one chiral OH-PCB: namely, 5-OH-PCB95.
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Affiliation(s)
- Guangshu Zhai
- Department
of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, The University of Iowa, Iowa City, Iowa 52242, United States
- Phone: +1 319 335 5647; fax: 319 335 5660; e-mail:
| | - Sarah M. Gutowski
- Department
of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, 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
| | - Jerald
L. Schnoor
- Department
of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, The University of Iowa, Iowa City, Iowa 52242, United States
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
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20
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Dhakal K, Uwimana E, Adamcakova-Dodd A, Thorne PS, Lehmler HJ, Robertson LW. Disposition of phenolic and sulfated metabolites after inhalation exposure to 4-chlorobiphenyl (PCB3) in female rats. Chem Res Toxicol 2014; 27:1411-20. [PMID: 24988477 PMCID: PMC4137987 DOI: 10.1021/tx500150h] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PCBs, such as PCB3, are air contaminants in buildings and outdoors. Metabolites of PCB3 are potential endocrine disrupting chemicals and genotoxic agents. We studied the disposition of phenolic and sulfated metabolites after acute nose-only inhalation exposure to airborne PCB3 for 2 h in female rats. Inhalation exposure was carried out in three groups. In the first group, rats exposed to an estimated dose of 26 μg/rat were euthanized at 0, 1, 2, and 4 h after exposure. Highest concentrations of phenols and sulfates were observed at 0 h, and the values were 7 ± 1 and 560 ± 60 ng/mL in serum, 213 ± 120 and 842 ± 80 ng/g in liver, 31 ± 27 and 22 ± 7 ng/g in lung, and 27 ± 6 and 3 ± 0 ng/g in brain, respectively. First-order serum clearance half-lives of 0.5 h for phenols and 1 h for sulfates were estimated. In the second group, rats exposed to an estimated dose of 35 μg/rat were transferred to metabolism cages immediately after exposure for the collection of urine and feces over 24 h. Approximately 45 ± 5% of the dose was recovered from urine and consisted mostly of sulfates; the 18 ± 5% of the dose recovered from feces was exclusively phenols. Unchanged PCB3 was detected in both urine and feces but accounted for only 5 ± 3% of the dose. Peak excretion of metabolites in both urine and feces occurred within 18 h postexposure. In the third group, three bile-cannulated rats exposed to an estimated dose of 277 μg/rat were used for bile collection. Bile was collected for 4 h immediately after 2 h exposure. Biliary metabolites consisted mostly of sulfates, some glucuronides, and lower amounts of the free phenols. Control rats in each group were exposed to clean air. Clinical serum chemistry values, serum T4 level, and urinary 8-hydroxy-2'-deoxyguanosine were similar in treated and control rats. These data show that PCB3 is rapidly metabolized to phenols and conjugated to sulfates after inhalation and that both of these metabolites are distributed to liver, lungs, and brain. The sulfates elaborated into bile are either reabsorbed or hydrolyzed in the intestine and excreted in the feces as phenols.
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Affiliation(s)
- Kiran Dhakal
- Interdisciplinary Graduate Program in Human Toxicology and ‡Department of Occupational and Environmental Health, The University of Iowa , Iowa City, Iowa 52242-5000, United States
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21
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James MO, Ambadapadi S. Interactions of cytosolic sulfotransferases with xenobiotics. Drug Metab Rev 2014; 45:401-14. [PMID: 24188364 DOI: 10.3109/03602532.2013.835613] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Cytosolic sulfotransferases are a superfamily of enzymes that catalyze the transfer of the sulfonic group from 3'-phosphoadenosine-5'-phosphosulfate to hydroxy or amine groups in substrate molecules. The human cytosolic sulfotransferases that have been most studied, namely SULT1A1, SULT1A3, SULT1B1, SULT1E1 and SULT2A1, are expressed in different tissues of the body, including liver, intestine, adrenal, brain and skin. These sulfotransferases play important roles in the sulfonation of endogenous molecules such as steroid hormones and neurotransmitters, and in the elimination of xenobiotic molecules such as drugs, environmental chemicals and natural products. There is often overlapping substrate selectivity among the sulfotransferases, although one isoform may exhibit greater enzyme efficiency than other isoforms. Similarly, inhibitors or enhancers of one isoform often affect other isoforms, but typically with different potency. This means that if the activity of one form of sulfotransferase is altered (either inhibited or enhanced) by the presence of a xenobiotic, the sulfonation of endogenous and xenobiotic substrates for other isoforms may well be affected. There are more examples of inhibitors than enhancers of sulfonation. Modulators of sulfotransferase enzymes include natural products ingested as part of the human diet as well as environmental chemicals and drugs. This review will discuss recent work on such interactions.
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Affiliation(s)
- Margaret O James
- Department of Medicinal Chemistry, University of Florida, Gainesville , FL , USA
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22
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Testai E, Galli CL, Dekant W, Marinovich M, Piersma AH, Sharpe RM. A plea for risk assessment of endocrine disrupting chemicals. Toxicology 2013; 314:51-9. [DOI: 10.1016/j.tox.2013.07.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 07/30/2013] [Indexed: 12/20/2022]
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23
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Qin X, Lehmler HJ, Teesch LM, Robertson LW, Duffel MW. Chlorinated biphenyl quinones and phenyl-2,5-benzoquinone differentially modify the catalytic activity of human hydroxysteroid sulfotransferase hSULT2A1. Chem Res Toxicol 2013; 26:1474-85. [PMID: 24059442 DOI: 10.1021/tx400207q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Human hydroxysteroid sulfotransferase (hSULT2A1) catalyzes the sulfation of a broad range of environmental chemicals, drugs, and other xenobiotics in addition to endogenous compounds that include hydroxysteroids and bile acids. Polychlorinated biphenyls (PCBs) are persistent environmental contaminants, and oxidized metabolites of PCBs may play significant roles in the etiology of their adverse health effects. Quinones derived from the oxidative metabolism of PCBs (PCB-quinones) react with nucleophilic sites in proteins and also undergo redox cycling to generate reactive oxygen species. This, along with the sensitivity of hSULT2A1 to oxidative modification at cysteine residues, led us to hypothesize that electrophilic PCB-quinones react with hSULT2A1 to alter its catalytic function. Thus, we examined the effects of four phenylbenzoquinones on the ability of hSULT2A1 to catalyze the sulfation of the endogenous substrate, dehydroepiandrosterone (DHEA). The quinones studied were 2'-chlorophenyl-2,5-benzoquinone (2'-Cl-BQ), 4'-chlorophenyl-2,5-benzoquinone (4'-Cl-BQ), 4'-chlorophenyl-3,6-dichloro-2,5-benzoquinone (3,6,4'-triCl-BQ), and phenyl-2,5-benzoquinone (PBQ). At all concentrations examined, pretreatment of hSULT2A1 with the PCB-quinones decreased the catalytic activity of hSULT2A1. Pretreatment with low concentrations of PBQ, however, increased the catalytic activity of the enzyme, while higher concentrations inhibited catalysis. A decrease in substrate inhibition with DHEA was seen following preincubation of hSULT2A1 with all of the quinones. Proteolytic digestion of the enzyme followed by LC/MS analysis indicated PCB-quinone- and PBQ-adducts at Cys55 and Cys199, as well as oxidation products at methionines in the protein. Equilibrium binding experiments and molecular modeling suggested that changes due to these modifications may affect the nucleotide binding site and the entrance to the sulfuryl acceptor binding site of hSULT2A1.
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Affiliation(s)
- Xiaoyan Qin
- Interdisciplinary Graduate Program in Human Toxicology, University of Iowa , Iowa City, Iowa 52242, United States
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24
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Ludewig G, Robertson LW. Polychlorinated biphenyls (PCBs) as initiating agents in hepatocellular carcinoma. Cancer Lett 2013; 334:46-55. [PMID: 23211541 PMCID: PMC3648605 DOI: 10.1016/j.canlet.2012.11.041] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 11/20/2012] [Accepted: 11/25/2012] [Indexed: 12/11/2022]
Abstract
PCBs are carcinogens, but for many decades it was assumed that PCBs may not possess initiating activity. Initiation is a process that involves changes in the DNA sequence, often, but not exclusively produced through DNA adduction by a reactive compound or reactive oxygen species (ROS). DNA adducts can be detected by (32)P-postlabeling, a method that Dr. Ramesh Gupta co-developed and refined. Today these types of assays together with other mechanistic studies provide convincing evidence that specific PCB congeners can be biotransformed to genotoxic and therefore potentially initiating metabolites. This review will provide an overview of our current knowledge of PCBs' genotoxic potential and mechanism of action, emphasizing the contributions of Dr. Ramesh Gupta during his tenures at the Universities of Kentucky and Louisville.
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Affiliation(s)
- Gabriele Ludewig
- The University of Iowa, 100 Oakdale Campus, IREH, Iowa City, IA 52242-5000, United States.
| | - Larry W Robertson
- The University of Iowa, 100 Oakdale Campus, IREH, Iowa City, IA 52242-5000, United States
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25
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Dhakal K, Adamcakova-Dodd A, Lehmler HJ, Thorne PS, Robertson LW. Sulfate conjugates are urinary markers of inhalation exposure to 4-chlorobiphenyl (PCB3). Chem Res Toxicol 2013; 26:853-5. [PMID: 23713983 PMCID: PMC3703249 DOI: 10.1021/tx4001539] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PCBs are contaminants in the air of older buildings and cities, which raises the concern of inhalation exposure. No reliable biomarker of such exposure is available. We exposed rats to air containing 2 mg/m(3) PCB3 via nose-only inhalation for 2 h, collected urine, and analyzed it by LC/MS. Each rat inhaled an estimated dose of 35 μg PCB3, and excreted 27 ± 2% of it as sulfates within 24 h. Peak excretion occurred within 6 h. PCB sulfates were stable in urine for at least three days at room temperature without chemical preservatives. These data support the use of PCB sulfate conjugates as suitable urinary biomarkers of PCB3 and other airborne PCBs.
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Affiliation(s)
- Kiran Dhakal
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa 52242, United States
| | - Andrea Adamcakova-Dodd
- 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
| | - Peter S. Thorne
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa 52242, United States
| | - Larry W. Robertson
- 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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26
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Grimm FA, Lehmler HJ, He X, Robertson LW, Duffel MW. Sulfated metabolites of polychlorinated biphenyls are high-affinity ligands for the thyroid hormone transport protein transthyretin. ENVIRONMENTAL HEALTH PERSPECTIVES 2013; 121:657-62. [PMID: 23584369 PMCID: PMC3672920 DOI: 10.1289/ehp.1206198] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 04/11/2013] [Indexed: 05/20/2023]
Abstract
BACKGROUND The displacement of l-thyroxine (T4) from binding sites on transthyretin (TTR) is considered a significant contributing mechanism in polychlorinated biphenyl (PCB)-induced thyroid disruption. Previous research has discovered hydroxylated PCB metabolites (OH-PCBs) as high-affinity ligands for TTR, but the binding potential of conjugated PCB metabolites such as PCB sulfates has not been explored. OBJECTIVES We evaluated the binding of five lower-chlorinated PCB sulfates to human TTR and compared their binding characteristics to those determined for their OH-PCB precursors and for T4. METHODS We used fluorescence probe displacement studies and molecular docking simulations to characterize the binding of PCB sulfates to TTR. The stability of PCB sulfates and the reversibility of these interactions were characterized by HPLC analysis of PCB sulfates after their binding to TTR. The ability of OH-PCBs to serve as substrates for human cytosolic sulfotransferase 1A1 (hSULT1A1) was assessed by OH-PCB-dependent formation of adenosine-3',5'-diphosphate, an end product of the sulfation reaction. RESULTS All five PCB sulfates were able to bind to the high-affinity binding site of TTR with equilibrium dissociation constants (Kd values) in the low nanomolar range (4.8-16.8 nM), similar to that observed for T4 (4.7 nM). Docking simulations provided corroborating evidence for these binding interactions and indicated multiple high-affinity modes of binding. All OH-PCB precursors for these sulfates were found to be substrates for hSULT1A1. CONCLUSIONS Our findings show that PCB sulfates are high-affinity ligands for human TTR and therefore indicate, for the first time, a potential relevance for these metabolites in PCB-induced thyroid disruption.
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Affiliation(s)
- Fabian A Grimm
- Interdisciplinary Graduate Program in Human Toxicology, Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, College of Public Health, The University of Iowa, Iowa City, Iowa 52246, USA
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27
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Qin X, Teesch LM, Duffel MW. Modification of the catalytic function of human hydroxysteroid sulfotransferase hSULT2A1 by formation of disulfide bonds. Drug Metab Dispos 2013; 41:1094-103. [PMID: 23444386 PMCID: PMC3629806 DOI: 10.1124/dmd.112.050534] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 02/26/2013] [Indexed: 01/01/2023] Open
Abstract
The human cytosolic sulfotransferase hSULT2A1 catalyzes the sulfation of a broad range of xenobiotics, as well as endogenous hydroxysteroids and bile acids. Reversible modulation of the catalytic activity of this enzyme could play important roles in its physiologic functions. Whereas other mammalian sulfotransferases are known to be reversibly altered by changes in their redox environment, this has not been previously shown for hSULT2A1. We have examined the hypothesis that the formation of disulfide bonds in hSULT2A1 can reversibly regulate the catalytic function of the enzyme. Three thiol oxidants were used as model compounds to investigate their effects on homogeneous preparations of hSULT2A1: glutathione disulfide, 5,5'-dithiobis(2-nitrobenzoic acid), and 1,1'-azobis(N,N-dimethylformamide) (diamide). Examination of the effects of disulfide bond formation with these agents indicated that the activity of the enzyme is reversibly altered. Studies on the kinetics of the hSULT2A1-catalyzed sulfation of dehydroepiandrosterone (DHEA) showed the effects of disulfide bond formation on the substrate inhibition characteristics of the enzyme. The effects of these agents on the binding of substrates and products, liquid chromatography-mass spectrometry identification of the disulfides formed, and structural modeling of the modified enzyme were examined. Our results indicate that conformational changes at cysteines near the nucleotide binding site affect the binding of both the nucleotide and DHEA to the enzyme, with the specific effects dependent on the structure of the resulting disulfide. Thus, the formation of disulfide bonds in hSULT2A1 is a potentially important reversible mechanism for alterations in the rates of sulfation of both endogenous and xenobiotic substrates.
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Affiliation(s)
- Xiaoyan Qin
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, The University of Iowa, Iowa City, Iowa, USA
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28
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Lehmler HJ, He X, Duffel MW, Parkin S. 3,4',5-Trichloro-biphenyl-4-yl 2,2,2-trichloro-ethyl sulfate. Acta Crystallogr Sect E Struct Rep Online 2013; 69:o620. [PMID: 23634142 PMCID: PMC3629655 DOI: 10.1107/s1600536813007976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Accepted: 03/22/2013] [Indexed: 11/11/2022]
Abstract
Crystals of the title compound, C14H8Cl6O4S, are twinned by inversion, with unequal components [0.85 (3):0.15 (3)]. The asymmetric unit contains two independent mol-ecules that are related by a pseudo-inversion center. The Car-O [1.393 (9) and 1.397 (9) Å] and ester S-O bond lengths [1.600 (5) and 1.590 (5) Å] of both mol-ecules are comparable to the structurally related 2,3,5,5-trichloro-biphenyl-4-yl 2,2,2-trichloro-ethyl sulfate. The dihedral angles between the benzene rings in the two mol-ecules are 37.8 (2) and 35.0 (2)°.
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Affiliation(s)
- Hans-Joachim Lehmler
- The University of Iowa, Department of Occupational and Environmental Health, Iowa City, IA 52242, USA
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29
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Dhakal K, He X, Lehmler HJ, Teesch LM, Duffel MW, Robertson LW. Identification of sulfated metabolites of 4-chlorobiphenyl (PCB3) in the serum and urine of male rats. Chem Res Toxicol 2012; 25:2796-804. [PMID: 23137097 DOI: 10.1021/tx300416v] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polychlorinated biphenyls (PCBs) are legacy pollutants that exert toxicities through various mechanisms. In recent years exposure to PCBs via inhalation has been recognized as a hazard. Those PCBs with lower numbers of chlorine atoms (LC-PCBs) are semivolatile and have been reported in urban air, as well as in the indoor air of older buildings. LC-PCBs are bioactivated to phenols and further to quinone electrophiles with genotoxic/carcinogenic potential. We hypothesized that phenolic LC-PCBs are subject to conjugation and excretion in the urine. PCB3, often present in high concentrations in air, is a prototypical congener for the study of the metabolism and toxicity of LC-PCBs. Our objective was to identify metabolites of PCB3 in urine that could be potentially employed in the estimation of exposure to LC-PCBs. Male Sprague-Dawley rats (150-175 g) were housed in metabolism cages and received a single intraperitoneal injection of 600 μmol/kg body weight of PCB3. Urine was collected every 4 h; rats were euthanized at 36 h; and serum was collected. LC/MS analysis of urine before and after incubation with β-glucuronidase and sulfatase showed that sulfate conjugates were in higher concentrations than glucuronide conjugates and free phenolic forms. At least two major metabolites and two minor metabolites were identified in urine that could be attributed to mercapturic acid metabolites of PCB3. Quantitation by authentic standards confirmed that approximately 3% of the dose was excreted in the urine as sulfates over 36 h, with peak excretion occurring at 10-20 h after exposure. The major metabolites were 4'PCB3sulfate, 3'PCB3 sulfate, 2'PCB3 sulfate, and presumably a catechol sulfate. The serum concentration of 4'PCB3 sulfate was 6.18 ± 2.16 μg/mL. This is the first report that sulfated metabolites of PCBs are formed in vivo. These findings suggest a prospective approach for exposure assessment of LC-PCBs by analysis of phase II metabolites in urine.
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Affiliation(s)
- Kiran Dhakal
- Interdisciplinary Graduate Program in Human Toxicology, University of Iowa, Iowa City, Iowa 52242, United States
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30
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Dammanahalli JK, Duffel MW. Oxidative modification of rat sulfotransferase 1A1 activity in hepatic tissue slices correlates with effects on the purified enzyme. Drug Metab Dispos 2011; 40:298-303. [PMID: 22041107 DOI: 10.1124/dmd.111.042044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Mammalian cytosolic sulfotransferases (SULTs) catalyze the sulfation of xenobiotics as well as numerous endogenous molecules. The major aryl (phenol) SULT in rat liver, rSULT1A1, has been used extensively as a model enzyme for understanding the catalytic function of SULTs. Previous studies showed that purified rSULT1A1 displays significant catalytic changes in the presence of GSSG and other oxidants. In the present study, the effects of diamide [1,1'-azobis(N,N-dimethylformamide)] and tert-butyl hydroperoxide (TBHP) on the activity of rSULT1A1 in rat hepatic slices were compared with the effects of these oxidants on a homogeneous preparation of the enzyme. Precision-cut hepatic slices were incubated with 10 μM 7-hydroxycoumarin (7-HC) in the presence of varied concentrations of either diamide or TBHP. Analysis of the 7-hydroxycoumarin sulfate released into the incubation medium indicated that both oxidants significantly increased the sulfation of 7-HC, and this occurred at optimal concentrations of 5 and 10 μM, respectively. Cellular GSH and GSSG levels in the hepatic slices were not significantly altered from control values at these concentrations of diamide and TBHP. Exposure of homogeneous rSULT1A1 to diamide or TBHP also increased the rate of sulfation of 7-HC, although the optimal concentrations of diamide and TBHP were lower (50- and 100-fold, respectively) than those required for effects with the hepatic slices. These results indicate that both diamide and TBHP may modify the rSULT1A1 in intact cells in a manner similar to that observed with the homogeneous purified enzyme.
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Affiliation(s)
- Jagadeesha K Dammanahalli
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, 115 S. Grand Ave., Iowa City, IA 52242, USA
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Liu Y, Lehmler HJ, Robertson LW, Duffel MW. Physicochemical properties of hydroxylated polychlorinated biphenyls aid in predicting their interactions with rat sulfotransferase 1A1 (rSULT1A1). Chem Biol Interact 2011; 189:153-60. [PMID: 21130751 PMCID: PMC3032042 DOI: 10.1016/j.cbi.2010.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 11/24/2010] [Accepted: 11/25/2010] [Indexed: 10/18/2022]
Abstract
Hydroxylated metabolites of polychlorinated biphenyls (OHPCBs) interact with rat sulfotransferase 1A1 (rSULT1A1) as substrates and inhibitors. Previous studies have shown that there are complex and incompletely understood structure-activity relationships governing the interaction of rSULT1A1 with these molecules. Furthermore, modification of the enzyme with glutathione disulfide (GSSG) results in the conversion of some OHPCBs from inhibitors to substrates. We have now examined estimated values for the acid-dissociation constant (K(a)) and the octanol-water distribution coefficient (D), as well as experimentally determined dissociation constants for enzyme complexes, to assist in the prediction of interactions of OHPCBs with rSULT1A1. Under reducing conditions, initial velocities for rSULT1A1-catalyzed sulfation exhibited a positive correlation with pK(a) and a negative correlation with logD of the OHPCBs. IC(50) values of inhibitory OHPCBs decreased with decreasing pK(a) values for both the glutathione (GSH)-pretreated and GSSG-pretreated forms of rSULT1A1. Comparison of GSH- and GSSG-pretreated forms of rSULT1A1 with respect to binding of OHPCB in the presence and absence of adenosine 3',5'-diphosphate (PAP) revealed that the dissociation constants with the two redox states of the enzyme were similar for each OHPCB. Thus, pK(a) and logD values are useful in predicting the binding of OHPCBs to the two redox forms of rSULT1A1 as well as the rates of sulfation of those OHPCBs that are substrates. However, the differences in substrate specificity for OHPCBs that are seen with changes in redox status of the enzyme are not directly related to specific structural effects of individual OHPCBs within inhibitory enzyme-PAP-OHPCB complexes.
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Affiliation(s)
- Yungang Liu
- Division of Medicinal and Natural Products Chemistry, College of Pharmacy University of Iowa, Iowa City, IA 52242
- School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guandong, China 510515
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242
| | - Larry W. Robertson
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA 52242
| | - Michael W. Duffel
- Division of Medicinal and Natural Products Chemistry, College of Pharmacy University of Iowa, Iowa City, IA 52242
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32
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Li X, Parkin S, Duffel MW, Robertson LW, Lehmler HJ. 4'-Chloro-biphenyl-3-yl 2,2,2-trichloro-ethyl sulfate. Acta Crystallogr Sect E Struct Rep Online 2010; 66:o2306. [PMID: 21588655 PMCID: PMC3008081 DOI: 10.1107/s1600536810031338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 08/04/2010] [Indexed: 11/12/2022]
Abstract
The title compound, C14H10Cl4O4S, is a 2,2,2-trichloroethyl-protected precursor of 4′-chlorobiphenyl-3-yl sulfate, a sulfuric acid ester of 4′-chlorobiphenyl-3-ol. The Caromatic—O and O—S bond lengths of the Caromatic—O—S unit are comparable to those in structurally analogous biphenyl-4-yl 2,2,2-trichloroethyl sulfates with no electronegative chlorine substituent in the benzene ring with the sulfate ester group. The dihedral angle between the aromatic rings is 27.47 (6)°.
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Li X, Parkin S, Duffel MW, Robertson LW, Lehmler HJ. 3',4'-Dichloro-biphenyl-4-yl 2,2,2-trichloro-ethyl sulfate. Acta Crystallogr Sect E Struct Rep Online 2010; 66:o1615-6. [PMID: 21587847 PMCID: PMC3006693 DOI: 10.1107/s1600536810020362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 05/28/2010] [Indexed: 11/11/2022]
Abstract
The four independent molecules in the asymmetric unit of the title compound, C14H9Cl5O4S, are related by pseudo-inversion centres. The molecules have Caromatic—O bond lengths ranging from 1.426 (10) to 1.449 (9) Å and biphenyl-4-yl sulfate ester bond lengths ranging from 1.563 (6) to 1.586 (6) Å, which is comparable to structurally related sulfuric acid diesters. The dihedral angles between the benzene rings range from 22.5 (4) to 29.1 (4)° and are significantly smaller than the calculated dihedral angle of 41.2°.
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Li X, Parkin S, Duffel MW, Robertson LW, Lehmler HJ. Biphenyl-4-yl 2,2,2-trichloro-ethyl sulfate. Acta Crystallogr Sect E Struct Rep Online 2010; 66:o1073. [PMID: 21579128 PMCID: PMC2979148 DOI: 10.1107/s1600536810012845] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 04/06/2010] [Indexed: 11/15/2022]
Abstract
The mol-ecular structure of the title compound, C(14)H(11)Cl(3)O(4)S, displays a biphenyl dihedral angle of 4.9 (2)° between the benzene rings, which is significantly smaller than the calculated dihedral angle of 41.2° of biphenyl derivatives without ortho substituents. The C(Ar)-O bond length of 1.432 (4) Å is comparable with other sulfuric acid biphenyl-4-yl ester 2,2,2-trichloro-ether ester derivatives without electronegative substituents in the sulfated phenyl ring.
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Affiliation(s)
- Xueshu Li
- Department of Occupational and Environmental Health, University of Iowa, 100 Oakdale Campus, 124 IREH, Iowa City, IA 52242-5000, USA
| | - Sean Parkin
- Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055, USA
| | - Michael W. Duffel
- College of Pharmacy, Division of Medicinal and Natural Products Chemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Larry W. Robertson
- Department of Occupational and Environmental Health, University of Iowa, 100 Oakdale Campus, 124 IREH, Iowa City, IA 52242-5000, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, University of Iowa, 100 Oakdale Campus, 124 IREH, Iowa City, IA 52242-5000, USA
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Pessah IN, Cherednichenko G, Lein PJ. Minding the calcium store: Ryanodine receptor activation as a convergent mechanism of PCB toxicity. Pharmacol Ther 2010; 125:260-85. [PMID: 19931307 PMCID: PMC2823855 DOI: 10.1016/j.pharmthera.2009.10.009] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 10/30/2009] [Indexed: 11/24/2022]
Abstract
Chronic low-level polychlorinated biphenyl (PCB) exposures remain a significant public health concern since results from epidemiological studies indicate that PCB burden is associated with immune system dysfunction, cardiovascular disease, and impairment of the developing nervous system. Of these various adverse health effects, developmental neurotoxicity has emerged as a particularly vulnerable endpoint in PCB toxicity. Arguably the most pervasive biological effects of PCBs could be mediated by their ability to alter the spatial and temporal fidelity of Ca2+ signals through one or more receptor-mediated processes. This review will focus on our current knowledge of the structure and function of ryanodine receptors (RyRs) in muscle and nerve cells and how PCBs and related non-coplanar structures alter these functions. The molecular and cellular mechanisms by which non-coplanar PCBs and related structures alter local and global Ca2+ signaling properties and the possible short and long-term consequences of these perturbations on neurodevelopment and neurodegeneration are reviewed.
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Affiliation(s)
- Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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Dreiem A, Rykken S, Lehmler HJ, Robertson LW, Fonnum F. Hydroxylated polychlorinated biphenyls increase reactive oxygen species formation and induce cell death in cultured cerebellar granule cells. Toxicol Appl Pharmacol 2009; 240:306-13. [PMID: 19631230 PMCID: PMC2753730 DOI: 10.1016/j.taap.2009.07.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 07/15/2009] [Accepted: 07/15/2009] [Indexed: 11/20/2022]
Abstract
Polychlorinated biphenyls (PCBs) are persistent organic pollutants that bioaccumulate in the body, however, they can be metabolized to more water-soluble products. Although they are more readily excreted than the parent compounds, some of the metabolites are still hydrophobic and may be more available to target tissues, such as the brain. They can also cross the placenta and reach a developing foetus. Much less is known about the toxicity of PCB metabolites than about the parent compounds. In the present study, we have investigated the effects of eight hydroxylated (OH) PCB congeners (2'-OH PCB 3, 4-OH PCB 14, 4-OH PCB 34, 4'-OH PCB 35, 4-OH PCB 36, 4'-OH PCB 36, 4-OH PCB 39, and 4'-OH PCB 68) on reactive oxygen species (ROS) formation and cell viability in rat cerebellar granule cells. We found that, similar to their parent compounds, OH-PCBs are potent ROS inducers with potency 4-OH PCB 14<4-OH PCB 36<4-OH PCB 34<4'-OH PCB 36<4'-OH PCB 68<4-OH PCB 39<4'-OH PCB 35. 4-OH PCB 36 was the most potent cell death inducer, and caused apoptotic or necrotic morphology depending on concentration. Inhibition of ERK1/2 kinase with U0126 reduced both cell death and ROS formation, suggesting that ERK1/2 activation is involved in OH-PCB toxicity. The results indicate that the hydroxylation of PCBs may not constitute a detoxification reaction. Since OH-PCBs like their parent compounds are retained in the body and may be more widely distributed to sensitive tissues, it is important that not only the levels of the parent compounds but also the levels of their metabolites are taken into account during risk assessment of PCBs and related compounds.
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Affiliation(s)
- Anne Dreiem
- Department of Biochemistry, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
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