1
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Paranjape N, Dean LE, Martinez A, Tjalkens RB, Lehmler HJ, Doorn JA. Structure-Activity Relationship of Lower Chlorinated Biphenyls and Their Human-Relevant Metabolites for Astrocyte Toxicity. Chem Res Toxicol 2023; 36:971-981. [PMID: 37279407 PMCID: PMC10283044 DOI: 10.1021/acs.chemrestox.3c00095] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Indexed: 06/08/2023]
Abstract
Exposure to polychlorinated biphenyls (PCBs) is associated with developmental neurotoxicity and neurodegenerative disorders; however, the underlying mechanisms of pathogenesis are unknown. Existing literature has focused mainly on using neurons as a model system to study mechanisms of PCB-mediated neurotoxicity, overlooking the role of glial cells, such as astrocytes. As normal brain function is largely astrocyte-dependent, we hypothesize that astrocytes play an important role in PCB-mediated injury to neurons. We assessed the toxicity of two commercial PCB mixtures, Aroclor 1016 and Aroclor 1254, and a non-Aroclor PCB mixture found in residential air called the Cabinet mixture, all of which contain lower chlorinated PCBs (LC-PCBs) found in indoor and outdoor air. We further assessed the toxicity of five abundant airborne LC-PCBs and their corresponding human-relevant metabolites in vitro models of astrocytes, namely, the C6 cell line and primary astrocytes isolated from Sprague-Dawley rats and C57BL/6 mice. PCB52 and its human-relevant hydroxylated and sulfated metabolites were found to be the most toxic compounds. No significant sex-dependent cell viability differences were observed in rat primary astrocytes. Based on the equilibrium partitioning model, it was predicted that the partitioning of LC-PCBs and their corresponding metabolites in biotic and abiotic compartments of the cell culture system is structure-dependent and that the observed toxicity is consistent with this prediction. This study, for the first time, shows that astrocytes are sensitive targets of LC-PCBs and their human-relevant metabolites and that further research to identify mechanistic targets of PCB exposure in glial cells is necessary.
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Affiliation(s)
- Neha Paranjape
- Department
of Pharmaceutical Sciences & Experimental Therapeutics, College
of Pharmacy, University of Iowa, Iowa City, Iowa 52242, United States
- Department
of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa 52242, United States
| | - Laura E. Dean
- Department
of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa 52242, United States
| | - Andres Martinez
- Department
of Civil and Environmental Engineering, IIHR-Hydroscience & Engineering, University of Iowa, Iowa City, Iowa 52242, United States
| | - Ronald B. Tjalkens
- Department
of Environmental and Radiological Health Sciences, College of Veterinary
Medicine and Biomedical Sciences, Colorado
State University, Fort Collins, Colorado 80521, United States
| | - Hans-Joachim Lehmler
- Department
of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa 52242, United States
| | - Jonathan A. Doorn
- Department
of Pharmaceutical Sciences & Experimental Therapeutics, College
of Pharmacy, University of Iowa, Iowa City, Iowa 52242, United States
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2
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De Oro-Carretero P, Sanz-Landaluze J. Miniaturized method for the quantification of persistent organic pollutants and their metabolites in HepG2 cells: assessment of their biotransformation. Anal Bioanal Chem 2023:10.1007/s00216-023-04781-w. [PMID: 37289209 DOI: 10.1007/s00216-023-04781-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/22/2023] [Accepted: 05/30/2023] [Indexed: 06/09/2023]
Abstract
Biotransformation can greatly influence the accumulation and, subsequently, toxicity of substances in living beings. Although traditionally these studies to quantify metabolization of a compound have been carried out with in vivo species, currently, in vitro test methods with very different cell lines are being developed for their evaluation. However, this is still a very limited field due to multiple variables of a very diverse nature. So, an increasing number of analytical chemists are working with cells or other similar biological samples of very small size. This makes it necessary to address the development of analytical methods that allow determining their concentration both inside the cells and in their exposure medium. The aim of this study is to develop a set of analytical methodologies for the quantification of polycyclic aromatic hydrocarbons, PAHs (phenanthrene, PHE), and polybrominated diphenyl ethers, PBDEs (2,2',4,4'-tetrabromodiphenyl ether, BDE-47), and their major metabolites in cells and their exposure medium. Analytical methodologies, based on miniaturized ultrasound probe-assisted extraction, gas chromatography-mass spectrometry-microelectron capture detector (GC-MS-µECD), and liquid chromatography-fluorescence detector (LC-FL) determination techniques, have been optimized and then applied to a biotransformation study in HepG2 at 48 h of exposure. Significant concentrations of the major metabolites of PHE (1-OH, 2-OH, 3-OH, 4-OH-, and 9-OH-PHE) and BDE-47 (5-MeO-, 5-OH-, and 3-OH-BDE-47) were detected and quantified inside the cells and in the exposure medium. These results provide a new method for determination and improve information on the metabolization ratios for a better knowledge of the metabolic pathways and their toxicity.
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Affiliation(s)
- Paloma De Oro-Carretero
- Department of Analytical Chemistry, Faculty of Chemical Science, Complutense University of Madrid, Avenida Complutense S/N, 28040, Madrid, Spain.
| | - Jon Sanz-Landaluze
- Department of Analytical Chemistry, Faculty of Chemical Science, Complutense University of Madrid, Avenida Complutense S/N, 28040, Madrid, Spain
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3
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Gourronc FA, Chimenti MS, Lehmler HJ, Ankrum JA, Klingelhutz AJ. Hydroxylation markedly alters how the polychlorinated biphenyl (PCB) congener, PCB52, affects gene expression in human preadipocytes. Toxicol In Vitro 2023; 89:105568. [PMID: 36804509 PMCID: PMC10081964 DOI: 10.1016/j.tiv.2023.105568] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 12/23/2022] [Accepted: 02/07/2023] [Indexed: 02/17/2023]
Abstract
Polychlorinated biphenyls (PCBs) accumulate in adipose tissue and are linked to obesity and diabetes. The congener, PCB52 (2,2',5,5'-tetrachorobiphenyl), is found at high levels in school air. Hydroxylation of PCB52 to 4-OH-PCB52 (4-hydroxy-2,2',5,5'-tetrachorobiphenyl) may increase its toxicity. To understand PCB52's role in causing adipose dysfunction, we exposed human preadipocytes to PCB52 or 4-OH-PCB52 across a time course and assessed transcript changes using RNAseq. 4-OH-PCB52 caused considerably more changes in the number of differentially expressed genes as compared to PCB52. Both PCB52 and 4-OH-PCB52 upregulated transcript levels of the sulfotransferase SULT1E1 at early time points, but cytochrome P450 genes were generally not affected. A set of genes known to be transcriptionally regulated by PPARα were consistently downregulated by PCB52 at all time points. In contrast, 4-OH-PCB52 affected a variety of pathways, including those involving cytokine responses, hormone responses, focal adhesion, Hippo, and Wnt signaling. Sets of genes known to be transcriptionally regulated by IL17A or parathyroid hormone (PTH) were found to be consistently downregulated by 4-OH-PCB52. Most of the genes affected by PCB52 and 4-OH-PCB52 were different and, of those that were the same, many were changed in an opposite direction. These studies provide insight into how PCB52 or its metabolites may cause adipose dysfunction to cause disease.
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Affiliation(s)
| | - Michael S Chimenti
- Iowa Institute of Human Genetics, Bioinformatics Division, University of Iowa, United States
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, University of Iowa, United States
| | - James A Ankrum
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, United States; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, United States
| | - Aloysius J Klingelhutz
- Department of Microbiology and Immunology, University of Iowa, United States; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, United States.
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4
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Martin N, Wassmur B, Baun A, Lammel T. Availability and effects of n-TiO 2 and PCB77 in fish in vitro models of the intestinal barrier and liver under single- and/or co-exposure scenarios. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 253:106343. [PMID: 36327689 DOI: 10.1016/j.aquatox.2022.106343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Titanium dioxide nanoparticles (n-TiO2) and polychlorinated biphenyls (PCBs) can be present in the food of fish, leading to intestinal exposure uptake, and accumulation in inner organs. This study examined combination effects of n-TiO2 and PCB77 in vitro models of the fish intestinal epithelium and liver, i.e., RTgut-GC cell cultures grown in ThinCerts™ and RTL-W1 cell cultures grown in standard tissue culture plates. Mass spectrometry and microscopy techniques were used to obtain information on nanoparticle translocation across the intestinal barrier model. In addition, the substances' effect on intestinal barrier permeability, cell viability, expression of dioxin - and antioxidant response element -controlled genes, and induction of cytochrome P450 1a (Cyp1a)-dependent ethoxyresorufin-O-deethylase (EROD) activity were assessed. TiO2 nanoparticles were taken up by RTgut-GC cells and detected in the bottom compartment of the intestinal epithelial barrier model. It was not possible to conclude definitively if n-TiO2 translocation occurred via transcytosis or paracellular migration but observations of nanoparticles in the lateral space between adjacent epithelial cells were rare. PCB77 (1 and 10 µM, 24 h) did not affect barrier permeability, i.e., n-TiO2 translocation is probably not facilitated in case of co-exposure. Furthermore, previous and simultaneous exposure to n-TiO2 (1 and 10 mg/L, 24 h) did not have any influence on PCB77-induced Cyp1a mRNA and enzyme activity levels in RTL-W1 cells. Furthermore, there were no significant differences in expression of antioxidant response element-controlled genes comparing control, single substance, and mixture treatments, not even following long-term exposure (0.01-1 mg/L n-TiO2 + 1 nM PCB77, 4 weeks). While an underestimation of the effects of n-TiO2 and PCB77 cannot be fully excluded as concentration losses due to sorption to cell culture plastics were not measured, the results suggest that the test substances probably have a low potential to exhibit combination effects on the assessed endpoints when co-existing in fish tissues.
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Affiliation(s)
- Nicolas Martin
- Department of Biological and Environmental Sciences, University of Gothenburg, Medicinaregatan 18 A, Box 463, Göteborg 413 90, Sweden
| | - Britt Wassmur
- Department of Biological and Environmental Sciences, University of Gothenburg, Medicinaregatan 18 A, Box 463, Göteborg 413 90, Sweden
| | - Anders Baun
- Department of Environmental and Resource Engineering, Technical University of Denmark, Building 115, 2800 Kgs., Lyngby, Denmark
| | - Tobias Lammel
- Department of Biological and Environmental Sciences, University of Gothenburg, Medicinaregatan 18 A, Box 463, Göteborg 413 90, Sweden.
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5
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Zhang CY, Li X, Keil Stietz KP, Sethi S, Yang W, Marek RF, Ding X, Lein PJ, Hornbuckle KC, Lehmler HJ. Machine Learning-Assisted Identification and Quantification of Hydroxylated Metabolites of Polychlorinated Biphenyls in Animal Samples. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:13169-13178. [PMID: 36047920 PMCID: PMC9573770 DOI: 10.1021/acs.est.2c02027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 08/15/2022] [Accepted: 08/22/2022] [Indexed: 06/02/2023]
Abstract
Laboratory studies of the disposition and toxicity of hydroxylated polychlorinated biphenyl (OH-PCB) metabolites are challenging because authentic analytical standards for most unknown OH-PCBs are not available. To assist with the characterization of these OH-PCBs (as methylated derivatives), we developed machine learning-based models with multiple linear regression (MLR) or random forest regression (RFR) to predict the relative retention times (RRT) and MS/MS responses of methoxylated (MeO-)PCBs on a gas chromatograph-tandem mass spectrometry system. The final MLR model estimated the retention times of MeO-PCBs with a mean absolute error of 0.55 min (n = 121). The similarity coefficients cos θ between the predicted (by RFR model) and experimental MS/MS data of MeO-PCBs were >0.95 for 92% of observations (n = 96). The levels of MeO-PCBs quantified with the predicted MS/MS response factors approximated the experimental values within a 2-fold difference for 85% of observations and 3-fold differences for all observations (n = 89). Subsequently, these model predictions were used to assist with the identification of OH-PCB 95 or OH-PCB 28 metabolites in mouse feces or liver by suggesting candidate ranking information for identifying the metabolite isomers. Thus, predicted retention and MS/MS response data can assist in identifying unknown OH-PCBs.
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Affiliation(s)
- Chun-Yun Zhang
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Xueshu Li
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Kimberly P. Keil Stietz
- Department
of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, California 95616, United States
| | - Sunjay Sethi
- Department
of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, California 95616, United States
| | - Weizhu Yang
- Department
of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, United States
| | - Rachel F. Marek
- Department
of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Xinxin Ding
- Department
of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, United States
| | - Pamela J. Lein
- Department
of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, California 95616, United States
| | - Keri C. Hornbuckle
- 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
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6
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Zhang CY, Li X, Flor S, Ruiz P, Kruve A, Ludewig G, Lehmler HJ. Metabolism of 3-Chlorobiphenyl (PCB 2) in a Human-Relevant Cell Line: Evidence of Dechlorinated Metabolites. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:12460-12472. [PMID: 35994059 PMCID: PMC9573771 DOI: 10.1021/acs.est.2c03687] [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] [Indexed: 05/09/2023]
Abstract
Lower chlorinated polychlorinated biphenyls (LC-PCBs) and their metabolites make up a class of environmental pollutants implicated in a range of adverse outcomes in humans; however, the metabolism of LC-PCBs in human models has received little attention. Here we characterize the metabolism of PCB 2 (3-chlorobiphenyl), an environmentally relevant LC-PCB congener, in HepG2 cells with in silico prediction and nontarget high-resolution mass spectrometry. Twenty PCB 2 metabolites belonging to 13 metabolite classes, including five dechlorinated metabolite classes, were identified in the cell culture media from HepG2 cells exposed for 24 h to 10 μM or 3.6 nM PCB 2. The PCB 2 metabolite profiles differed from the monochlorinated metabolite profiles identified in samples from an earlier study with PCB 11 (3,3'-dichlorobiphenyl) under identical experimental conditions. A dechlorinated dihydroxylated metabolite was also detected in human liver microsomal incubations with monohydroxylated PCB 2 metabolites but not PCB 2. These findings demonstrate that the metabolism of LC-PCBs in human-relevant models involves the formation of dechlorination products. In addition, untargeted metabolomic analyses revealed an altered bile acid biosynthesis in HepG2 cells. Our results indicate the need to study the disposition and toxicity of complex PCB 2 metabolites, including novel dechlorinated metabolites, in human-relevant models.
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Affiliation(s)
- Chun-Yun Zhang
- Hubei
Key Laboratory of Regional Development and Environmental Response,
Faculty of Resources and Environmental Science, Hubei University, Wuhan 430062, China
- Department
of Occupational and Environmental Health, 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
| | - Susanne Flor
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Patricia Ruiz
- Office
of Innovation and Analytics, Simulation Science Section, Agency for Toxic Substances and Disease Registry, Atlanta, Georgia 30333, United States
| | - Anneli Kruve
- Department
of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius Väg 16, 10691 Stockholm, Sweden
| | - Gabriele Ludewig
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Hans-Joachim Lehmler
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
- Phone: (319) 335-4981. Fax: (319) 335-4290.
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7
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Bloch S, Arnot JA, Kramer NI, Armitage JM, Verner MA. Dynamic Mass Balance Modeling for Chemical Distribution Over Time in In Vitro Systems With Repeated Dosing. FRONTIERS IN TOXICOLOGY 2022; 4:911128. [PMID: 36071822 PMCID: PMC9441784 DOI: 10.3389/ftox.2022.911128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 06/21/2022] [Indexed: 11/13/2022] Open
Abstract
As toxicologists and risk assessors move away from animal testing and more toward using in vitro models and biological modeling, it is necessary to produce tools to quantify the chemical distribution within the in vitro environment prior to extrapolating in vitro concentrations to human equivalent doses. Although models predicting chemical distribution in vitro have been developed, very little has been done for repeated dosing scenarios, which are common in prolonged experiments where the medium needs to be refreshed. Failure to account for repeated dosing may lead to inaccurate estimations of exposure and introduce bias into subsequent in vitro to in vivo extrapolations. Our objectives were to develop a dynamic mass balance model for repeated dosing in in vitro systems; to evaluate model accuracy against experimental data; and to perform illustrative simulations to assess the impact of repeated doses on predicted cellular concentrations. A novel dynamic in vitro partitioning mass balance model (IV-MBM DP v1.0) was created based on the well-established fugacity approach. We parameterized and applied the dynamic mass balance model to single dose and repeat dosing scenarios, and evaluated the predicted medium and cellular concentrations against available empirical data. We also simulated repeated dosing scenarios for organic chemicals with a range of partitioning properties and compared the in vitro distributions over time. In single dose scenarios, for which only medium concentrations were available, simulated concentrations predicted measured concentrations with coefficients of determination (R2) of 0.85–0.89, mean absolute error within a factor of two and model bias of nearly one. Repeat dose scenario simulations displayed model bias <2 within the cell lysate, and ∼1.5-3 in the medium. The concordance between simulated and available experimental data supports the predictive capacity of the IV-MBM DP v1.0 tool, but further evaluation as empirical data becomes available is warranted, especially for cellular concentrations.
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Affiliation(s)
- Sherri Bloch
- Department of Occupational and Environmental Health, School of Public Health, Université de Montréal, Montreal, QC, Canada
- Centre de Recherche en Santé Publique, Université de Montréal et CIUSSS du Centre-Sud-de-l'Île-de-Montréal, Montreal, QC, Canada
| | - Jon A. Arnot
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, Scarborough, ON, Canada
- ARC Arnot Consulting and Research, Inc., Toronto, ON, Canada
| | - Nynke I. Kramer
- Division of Toxicology, Wageningen University, Wageningen, Netherlands
| | | | - Marc-André Verner
- Department of Occupational and Environmental Health, School of Public Health, Université de Montréal, Montreal, QC, Canada
- Centre de Recherche en Santé Publique, Université de Montréal et CIUSSS du Centre-Sud-de-l'Île-de-Montréal, Montreal, QC, Canada
- *Correspondence: Marc-André Verner,
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8
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Li X, Hefti MM, Marek RF, Hornbuckle KC, Wang K, Lehmler HJ. Assessment of Polychlorinated Biphenyls and Their Hydroxylated Metabolites in Postmortem Human Brain Samples: Age and Brain Region Differences. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:9515-9526. [PMID: 35658127 PMCID: PMC9260965 DOI: 10.1021/acs.est.2c00581] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Exposure to polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) has been implicated in neurodevelopmental disorders. However, the distribution of PCBs and OH-PCBs in the human brain has not been characterized. This study investigated the age-, sex-, and brain region-specific distribution of all 209 PCBs using gaschromatography-tandem mass spectrometry (GC-MS/MS) in neonatal (N = 7) and adult (N = 7) postmortem brain samples. OH-PCB analyses were performed by GC-MS/MS (as methylated derivatives) and, in a subset of samples, by nontarget liquid chromatography high-resolution mass spectrometry (Nt-LCMS). Fourteen higher chlorinated PCB congeners were observed with a detection frequency >50%. Six lower chlorinated PCBs were detected with a detection frequency >10%. Higher chlorinated PCBs were observed with higher levels in samples from adult versus younger donors. PCB congener profiles from adult donors showed more similarities across brain regions and donors than younger donors. We also assess the potential neurotoxicity of the PCB residues in the human brain with neurotoxic equivalency (NEQ) approaches. The median ΣNEQs, calculated for the PCB homologues, were 40-fold higher in older versus younger donors. Importantly, lower chlorinated PCBs made considerable contributions to the neurotoxic potential of PCB residues in some donors. OH-PCBs were identified for the first time in a small number of human brain samples by GC-MS/MS and Nt-LCMS analyses, and all contained four or fewer chlorine.
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Affiliation(s)
- Xueshu Li
- Department
of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa 52242, United States
| | - Marco M. Hefti
- Department
of Pathology, University of Iowa Hospital
and Clinics, Iowa City, Iowa 52242, United
States
| | - Rachel F. Marek
- IIHR-Hydroscience
and Engineering, University of Iowa, Iowa City, Iowa 52242, United States
- Department
of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa 52242, United States
| | - Keri C. Hornbuckle
- IIHR-Hydroscience
and Engineering, University of Iowa, Iowa City, Iowa 52242, United States
- Department
of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa 52242, United States
| | - Kai Wang
- Department
of Biostatistics, University of Iowa, Iowa City, Iowa 52242, United States
| | - Hans-Joachim Lehmler
- Department
of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa 52242, United States
- IIHR-Hydroscience
and Engineering, University of Iowa, Iowa City, Iowa 52242, United States
- . Phone: (319) 335-4310. Fax: (319) 335-4290
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9
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Chen Y, Cai Y, Chen C, Li M, Lu L, Yu Z, Wang S, Fang L, Xu S. Aroclor 1254 induced inhibitory effects on osteoblast differentiation in murine MC3T3-E1 cells through oxidative stress. Front Endocrinol (Lausanne) 2022; 13:940624. [PMID: 36353240 PMCID: PMC9637744 DOI: 10.3389/fendo.2022.940624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 10/04/2022] [Indexed: 11/21/2022] Open
Abstract
This study aimed to evaluate the osteotoxicity of polychlorinated biphenyls in murine osteoblastic MC3T3-E1 cells, and to explore the underlying mechanism focused on oxidative stress. The cells were exposed to Aroclor 1254 at concentrations of 2.5-20 µmol/L, and then cell viability, oxidative stress, intracellular calcium concentration, osteocalcin content, and calcium nodules formation were measured. Aroclor 1254 reduced cell viability and induced overproduction of intracellular reactive oxygen species in a dose-dependent manner. Activity of superoxide dismutase was decreased, and malondialdehyde content was promoted after exposure. Moreover, inhibitory effects of Aroclor 1254 on calcium metabolism and mineralization of osteoblasts were observed, as indicated by reduction of the intracellular calcium concentration, osteocalcin content, and modules formation rate. The decreased expression of osteocalcin, alkaline phosphatase, bone sialoprotein, and transient receptor potential vanilloid 6 further confirmed the impairment of Aroclor 1254 on calcium homeostasis and osteoblast differentiation. Addition of the antioxidant N-acetyl-L-cysteine partially restored the inhibitory effects on calcium metabolism and mineralization. In general, Aroclor 1254 exposure reduces calcium homeostasis, osteoblast differentiation and bone formation, and oxidative stress plays a vital role in the underlying molecular mechanism of osteotoxicity.
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Affiliation(s)
- Yu Chen
- Department of Orthopaedic Surgery (I), Shuguang Hospital, Shanghai University of Chinese Traditional Medicine, Shanghai, China
| | - Yuwei Cai
- Department of Orthopaedic Surgery (I), Shuguang Hospital, Shanghai University of Chinese Traditional Medicine, Shanghai, China
| | - Chunxiang Chen
- Department of Neurology, Yueyang Hospital of Integrated Chinese and Western Medicine Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Mengting Li
- Department of Neurology, Yueyang Hospital of Integrated Chinese and Western Medicine Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Lingdan Lu
- Department of Neurology, Yueyang Hospital of Integrated Chinese and Western Medicine Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Zhongxiang Yu
- Department of Orthopaedic Surgery (I), Shuguang Hospital, Shanghai University of Chinese Traditional Medicine, Shanghai, China
| | - Shuqiang Wang
- Department of Orthopaedic Surgery, Yueyang Hospital of Integrated Chinese and Western Medicine Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Lei Fang
- Department of Orthopaedic Surgery (I), Shuguang Hospital, Shanghai University of Chinese Traditional Medicine, Shanghai, China
- *Correspondence: Lei Fang, ; Shengming Xu,
| | - Shengming Xu
- Department of Orthopaedic Surgery (I), Shuguang Hospital, Shanghai University of Chinese Traditional Medicine, Shanghai, China
- *Correspondence: Lei Fang, ; Shengming Xu,
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10
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Zhang CY, Flor S, Ruiz P, Ludewig G, Lehmler HJ. Characterization of the Metabolic Pathways of 4-Chlorobiphenyl (PCB3) in HepG2 Cells Using the Metabolite Profiles of Its Hydroxylated Metabolites. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:9052-9062. [PMID: 34125531 PMCID: PMC8264946 DOI: 10.1021/acs.est.1c01076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The characterization of the metabolism of lower chlorinated PCB, such as 4-chlorobiphenyl (PCB3), is challenging because of the complex metabolite mixtures formed in vitro and in vivo. We performed parallel metabolism studies with PCB3 and its hydroxylated metabolites to characterize the metabolism of PCB3 in HepG2 cells using nontarget high-resolution mass spectrometry (Nt-HRMS). Briefly, HepG2 cells were exposed for 24 h to 10 μM PCB3 or its seven hydroxylated metabolites in DMSO or DMSO alone. Six classes of metabolites were identified with Nt-HRMS in the culture medium exposed to PCB3, including monosubstituted metabolites at the 3'-, 4'-, 3-, and 4- (1,2-shift product) positions and disubstituted metabolites at the 3',4'-position. 3',4'-Di-OH-3 (4'-chloro-3,4-dihydroxybiphenyl), which can be oxidized to a reactive and toxic PCB3 quinone, was a central metabolite that was rapidly methylated. The resulting hydroxylated-methoxylated metabolites underwent further sulfation and, to a lesser extent, glucuronidation. Metabolomic analyses revealed an altered tryptophan metabolism in HepG2 cells following PCB3 exposure. Some PCB3 metabolites were associated with alterations of endogenous metabolic pathways, including amino acid metabolism, vitamin A (retinol) metabolism, and bile acid biosynthesis. In-depth studies are needed to investigate the toxicities of PCB3 metabolites, especially the 3',4'-di-OH-3 derivatives identified in this study.
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Affiliation(s)
- Chun-Yun Zhang
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Susanne Flor
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Patricia Ruiz
- Office
of Innovation and Analytics, Simulation Science Section, Agency for Toxic Substances and Disease Registry, Atlanta, Georgia 30333, United States
| | - Gabriele Ludewig
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Hans-Joachim Lehmler
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
- . Tel.: (319) 335-4981. Fax: (319) 335-4290
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