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Bullert A, Wang H, Valenzuela AE, Neier K, Wilson RJ, Badley JR, LaSalle JM, Hu X, Lein PJ, Lehmler HJ. Interactions of Polychlorinated Biphenyls and Their Metabolites with the Brain and Liver Transcriptome of Female Mice. ACS Chem Neurosci 2024; 15:3991-4009. [PMID: 39392776 PMCID: PMC11587508 DOI: 10.1021/acschemneuro.4c00367] [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: 06/13/2024] [Revised: 09/20/2024] [Accepted: 10/03/2024] [Indexed: 10/13/2024] Open
Abstract
Exposure to polychlorinated biphenyls (PCBs) is linked to neurotoxic effects. This study aims to close knowledge gaps regarding the specific modes of action of PCBs in female C57BL/6J mice (>6 weeks) orally exposed for 7 weeks to a human-relevant PCB mixture (MARBLES mix) at 0, 0.1, 1, and 6 mg/kg body weight/day. PCB and hydroxylated PCB (OH-PCBs) levels were quantified in the brain, liver, and serum; RNA sequencing was performed in the striatum, prefrontal cortex, and liver, and metabolomic analyses were performed in the striatum. Profiles of PCBs but not their hydroxylated metabolites were similar in all tissues. In the prefrontal cortex, PCB exposure activated the oxidative phosphorylation respiration pathways, while suppressing the axon guidance pathway. PCB exposure significantly changed the expression of genes associated with neurodevelopmental and neurodegenerative diseases in the striatum, impacting pathways like growth hormone synthesis and dendrite development. PCBs did not affect the striatal metabolome. In contrast to the liver, which showed activation of metabolic processes following PCB exposure and the induction of cytochrome P450 enzymes, the expression of xenobiotic processing genes was not altered by PCB exposure in either brain region. Network analysis revealed complex interactions between individual PCBs (e.g., PCB28 [2,4,4'-trichlorobiphenyl]) and their hydroxylated metabolites and specific differentially expressed genes (DEGs), underscoring the need to characterize the association between specific PCBs and DEGs. These findings enhance the understanding of PCB neurotoxic mechanisms and their potential implications for human health.
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Affiliation(s)
- Amanda
J. Bullert
- Department
of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa 52242, United States
- Interdisciplinary
Graduate Program in Neuroscience, University
of Iowa, Iowa City, Iowa 52242, United States
| | - Hui Wang
- Department
of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa 52242, United States
| | - Anthony E. Valenzuela
- Department
of Molecular Biosciences, University of
California, Davis, California 95616, United States
| | - Kari Neier
- Department
of Medical Microbiology and Immunology, University of California, Davis, California 95616, United States
| | - Rebecca J. Wilson
- Department
of Molecular Biosciences, University of
California, Davis, California 95616, United States
| | - Jessie R. Badley
- Department
of Molecular Biosciences, University of
California, Davis, California 95616, United States
| | - Janine M. LaSalle
- Department
of Medical Microbiology and Immunology, University of California, Davis, California 95616, United States
| | - Xin Hu
- Gangarosa
Department of Environmental Health, Emory
University, Atlanta, Georgia 30329, United States
| | - Pamela J. Lein
- Department
of Molecular Biosciences, University of
California, Davis, California 95616, United States
| | - Hans-Joachim Lehmler
- Department
of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa 52242, United States
- Interdisciplinary
Graduate Program in Human Toxicology, University
of Iowa, Iowa City, Iowa 52242, United States
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2
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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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Sun X, Zhan F, Yu RQ, Chen L, Wu Y. Bio-accumulation of organic contaminants in Indo-Pacific humpback dolphins: Preliminary unique features of the brain and testes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 267:115511. [PMID: 32892017 DOI: 10.1016/j.envpol.2020.115511] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
There is little information about the residue levels and congener composition of organic contaminants (OCs) in cetaceans. In the present study, we investigated the polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in the blubber, blood, brain and testes of Indo-Pacific humpback dolphins (Sousa chinensis) stranded in the Pearl River Estuary (PRE), China. The lowest blubber/tissue partition coefficients were found for sum hexachlorocyclohexanes (ΣHCHs) and ΣPAHs, while the highest were in ΣPCBs and sum dichlorodiphenyltrichloroethanes (ΣDDTs), likely attributing to the octanol-water partition features. The low levels of OCs in brain and testes theoretically resulted from the blood-brain barrier, blood-testes barrier, contaminant molecule dimensions and unique lipid compositions in the brain and testes. Compared with other contaminants, the higher mean brain/blood and testes/blood partition coefficients found for mirex, heptachlor, dieldrin and endrin would increase the risks associated with exposure-related toxicity and the bioavailability of contaminants within these tissues. Observations also suggest that as lipid mobilizes from blubber, contaminants may redistribute, leading to elevated tissue (such as brain) concentrations. Therefore, dolphins with less blubber may be more susceptible to health risks. The Indo-Pacific humpback dolphins living in PRE are at great risk due to variety of OCs in indirect contact with non-target organisms, affecting the health of animals (toxic effects and accumulation). Our findings contribute to the knowledge of the potential effects of OCs exposure on developmental neurotoxicity and reproductive damage in marine mammals.
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Affiliation(s)
- Xian Sun
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai Key Laboratory of Marine Bioresources and Environment, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Fengping Zhan
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai Key Laboratory of Marine Bioresources and Environment, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Ri-Qing Yu
- Department of Biology, University of Texas at Tyler, Tyler, TX, 75799, USA
| | - Laiguo Chen
- Urban Environment and Ecology Research Center, South China Institute of Environmental Sciences (SCIES), Ministry of Environmental Protection, Guangzhou, 510655, China
| | - Yuping Wu
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai Key Laboratory of Marine Bioresources and Environment, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
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4
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Murati T, Miletić M, Pleadin J, Šimić B, Kmetič I. Cell membrane-related toxic responses and disruption of intercellular communication in PCB mechanisms of toxicity: A review. J Appl Toxicol 2020; 40:1592-1601. [PMID: 32648282 DOI: 10.1002/jat.4019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/13/2020] [Accepted: 05/15/2020] [Indexed: 02/06/2023]
Abstract
An understanding of polychlorinated biphenyl (PCB) congener-specific effects on cell membrane and intercellular communication is important within the studies of PCB absorption, organ-related PCB accumulation and exertion of toxic responses. Toxic potential of PCBs is linked to various deleterious effects on human health, including neurotoxicity, immunotoxicity, reproductive toxicity and genotoxicity and, recently in 2016 International Agency for Research on Cancer (IARC) has upgraded the classification of PCBs to Group 1 "Carcinogenic to humans." Proposed mechanisms of aforementioned PCBs adverse effects at cellular membrane level are: (i) downregulation of gap junction intercellular communication and/or connexins; (ii) compromised membrane integrity; and (iii) altered tight junction barrier function. This study, based on an extensive literature survey, shows the progress in scientific research of each of these three levels with the aim of pointing out the earliest toxic events of PCBs, which can result in serious cell/tissue/organ damage.
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Affiliation(s)
- Teuta Murati
- Laboratory for Toxicology, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia
| | - Marina Miletić
- Laboratory for Toxicology, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia
| | - Jelka Pleadin
- Laboratory for Analytical Chemistry, Department of Veterinary Public Health, Croatian Veterinary Institute, Zagreb, Croatia
| | - Branimir Šimić
- Laboratory for Toxicology, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia
| | - Ivana Kmetič
- Laboratory for Toxicology, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia
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5
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Lammel T, Wassmur B, Mackevica A, Chen CEL, Sturve J. Mixture toxicity effects and uptake of titanium dioxide (TiO 2) nanoparticles and 3,3',4,4'-tetrachlorobiphenyl (PCB77) in juvenile brown trout following co-exposure via the diet. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 213:105195. [PMID: 31203167 DOI: 10.1016/j.aquatox.2019.04.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 04/10/2019] [Accepted: 04/29/2019] [Indexed: 06/09/2023]
Abstract
Titanium dioxide nanoparticles (n-TiO2) are among the man-made nanomaterials that are predicted to be found at high concentrations in the aquatic environment. There, they likely co-exist with other chemical pollutants. Thus, n-TiO2 and other chemical pollutants can be taken up together or accumulate independently from each other in prey organisms of fish. This can lead to dietary exposure of fish to n-TiO2-chemical pollutant mixtures. In this study, we examine if simultaneous dietary exposure to n-TiO2 and 3,3',4,4'-Tetrachlorobiphenyl (PCB77) -used as a model compound for persistent organic pollutants with dioxin-like properties- can influence the uptake and toxicological response elicited by the respective other substance. Juvenile brown trout (Salmo trutta) were fed custom-made food pellets containing n-TiO2, PCB77 or n-TiO2+PCB77 mixtures for 15 days. Ti and PCB77 concentrations in the liver were measured by ICP-MS and GC-MS, respectively. Besides, n-TiO2 uptake was assessed using TEM. Combination effects on endpoints specific for PCB77 (i.e., cytochrome P450 1A (CYP1A) induction) and endpoints shared by both PCB77 and n-TiO2 (i.e., oxidative stress-related parameters) were measured in intestine and liver using RT-qPCR and enzyme activity assays. The results show that genes encoding for proteins/enzymes essential for tight junction function (zo-1) and ROS elimination (sod-1) were significantly upregulated in the intestine of fish exposed to n-TiO2 and PCB77 mixtures, but not in the single-substance treatments. Besides, n-TiO2 had a potentiating effect on PCB77-induced CYP1A and glutathione reductase (GR) expression/enzyme activity in the liver. This study shows that simultaneous dietary exposure to nanomaterials and traditional environmental pollutants might result in effects that are larger than observed for the substances alone, but that understanding the mechanistic basis of such effects remains challenging.
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Affiliation(s)
- Tobias Lammel
- Department of Biological and Environmental Sciences, Gothenburg University, Sweden.
| | - Britt Wassmur
- Department of Biological and Environmental Sciences, Gothenburg University, Sweden
| | - Aiga Mackevica
- TU Environment, Technical University of Denmark, Denmark
| | - Chang-Er L Chen
- Department of Environmental Sciences and Analytical Chemistry, Stockholm University, Sweden; Environmental Research Institute, South China Normal University, Guangzhou 510006, China
| | - Joachim Sturve
- Department of Biological and Environmental Sciences, Gothenburg University, Sweden
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Wang X, Xu Y, Song X, Jia Q, Zhang X, Qian Y, Qiu J. Analysis of glycerophospholipid metabolism after exposure to PCB153 in PC12 cells through targeted lipidomics by UHPLC-MS/MS. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 169:120-127. [PMID: 30445242 DOI: 10.1016/j.ecoenv.2018.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/01/2018] [Accepted: 11/01/2018] [Indexed: 06/09/2023]
Abstract
Polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) that have neurotoxicity, reproductive toxicity, hepatotoxicity and immunotoxicity in both animals and humans. Few studies have focused on the changes to endogenous glycerophospholipid metabolism caused by PCB153. To evaluate the relationships between exposure to PCB153 and specific endogenous glycerophospholipid metabolism, an ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was implemented in this study. Twenty-two endogenous glycerophospholipids in PC12 cells were analyzed after exposure to PCB153 at dosages of 0.05 μg mL-1, 0.5 μg mL-1 or 20 μg mL-1 for 120 h. PC(14:0/14:0), PE(16:0/18:1), PE(16:0/18:2), PS(18:0/18:1) and PI(16:0/18:1) were identified as potential biomarkers under the rules of t-test (P) value < 0.05 and variable importance at projection (VIP) value > 1. It was also found that the alterations at 0.05 μg mL-1 and 20 μg mL-1 PCB153 were similar at 120 h, while 0.5 μg mL-1 PCB153 presented an opposite trend. Additionally, significant upregulation of PC, PE and PS with the same fatty acid chains of 18:0/18:2 was found after exposure to 0.05 μg mL-1 and 20 μg mL-1 PCB153 at 120 h. This study revealed that PCB153 exposure modulated 22 endogenous glycerophospholipids in PC12 cells and provided the basis for the further study of PCB153 on the effects of glycerophospholipids on PC12 cells.
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Affiliation(s)
- Xinlu Wang
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Yanyang Xu
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Xiao Song
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Qi Jia
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Xining Zhang
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Yongzhong Qian
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China.
| | - Jing Qiu
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China.
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7
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Manthari RK, Tikka C, Ommati MM, Niu R, Sun Z, Wang J, Zhang J, Wang J. Arsenic induces autophagy in developmental mouse cerebral cortex and hippocampus by inhibiting PI3K/Akt/mTOR signaling pathway: involvement of blood-brain barrier's tight junction proteins. Arch Toxicol 2018; 92:3255-3275. [PMID: 30225639 DOI: 10.1007/s00204-018-2304-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 09/13/2018] [Indexed: 12/19/2022]
Abstract
For the past decade, there has been an increased concern about the health risks from arsenic (As) exposure, because of its neurotoxic effects on the developing brain. The exact mechanism underlying As-induced neurotoxicity during sensitive periods of brain development remains unclear, especially the role of blood-brain barrier's (BBB) tight junction (TJ) proteins during As-induced neurotoxicity. Here, we highlight the involvement of TJ proteins in As-induced autophagy in cerebral cortex and hippocampus during developmental periods [postnatal day (PND) 21, 28, 35 and 42]. Here, the administration of arsenic trioxide (As2O3) at doses of 0.15 mg or 1.5 mg or 15 mg As2O3/L in drinking water from gestational to lactational and continued to the pups till PND42 resulted in a significant decrease in the mRNA expression levels of TJ proteins (Occludin, Claudin, ZO-1 and ZO-2) and Occludin protein expression level. In addition, As exposure significantly decreased PI3K, Akt, mTOR, and p62 with a concomitant increase in Beclin1, LC3I, LC3II, Atg5 and Atg12. Moreover, As exposure also significantly downregulated the protein expression levels of mTOR with a concomitant upregulation of Beclin 1, LC3 and Atg12 in all the developmental age points. However, no significant alterations were observed in low and medium dose-exposed groups of PND42. Histopathological analysis in As-exposed mice revealed decreased number of pyramidal neurons in hippocampus; and neurons with degenerating axons, shrinkage of cells, remarkable vacuolar degeneration in cytoplasm, karyolysis and pyknosis in cerebral cortex. Ultrastructural analysis by transmission electron microscopy revealed the occurrence of autophagosomes and vacuolated axons in the cerebral cortex and hippocampus of the mice exposed to high dose As at PND21 and 42. The severities of changes were found to more persist in the cerebral cortex than in the hippocampus of As-exposed mice. Finally, we conclude that the leaky BBB in cerebral cortex and hippocampus may facilitate the transfer of As and induces autophagy by inhibiting PI3K/Akt/mTOR signaling pathway in an age-dependent manner, i.e., among the four different developmental age points, PND21 animals were found to be more vulnerable to the As-induced neurotoxicity than the other three age points.
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Affiliation(s)
- Ram Kumar Manthari
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Chiranjeevi Tikka
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Mohammad Mehdi Ommati
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China.,Department of Animal Science, College of Agriculture, Shiraz University, Shiraz, 71441-65186, Iran
| | - Ruiyan Niu
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Zilong Sun
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Jinming Wang
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Jianhai Zhang
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Jundong Wang
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China.
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Tang L, Cheng JN, Long Y, He XM, Liang GN, Tang XP, Jiang CX, Chen F. PCB 118-induced endothelial cell apoptosis is partially mediated by excessive ROS production. Toxicol Mech Methods 2017; 27:394-399. [PMID: 28399781 DOI: 10.1080/15376516.2017.1296050] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Endothelial cell apoptosis, which may alter the integrity of the endothelium and lead to plaque instability, plays a critical role in the development and pathogenesis of atherosclerosis. Exposure of polychlorinated biphenyls (PCBs) is associated with increased risk of atherosclerosis and cardiovascular disease. In our present study, we explored whether exposure to PCB 118 influences endothelial cell apoptosis in vitro and the underlying mechanisms involved. As expected, exposure to PCB 118 increased the intracellular reactive oxygen species (ROS) levels in HUVECs. Increases in apoptosis and Bax/Bcl-2 ratios were observed in PCB 118-treated HUVECs. N-acetyl-l-cysteine (NAC), a ROS scavenger, partially reduced PCB 118-induced apoptosis and Bax/Bcl-2 ratios in HUVECs. Taken together, PCB 118-induced endothelial cell apoptosis was partially initiated by excessive ROS production.
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Affiliation(s)
- Li Tang
- a Experimental Medicine Center, The Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
| | - Jin-Nan Cheng
- b Department of Dermatology , The Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
| | - Yang Long
- a Experimental Medicine Center, The Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China.,c Department of Endocrinology , The Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
| | - Xue-Mei He
- a Experimental Medicine Center, The Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
| | - Guan-Nan Liang
- a Experimental Medicine Center, The Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
| | - Xiao-Ping Tang
- a Experimental Medicine Center, The Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
| | - Chun-Xia Jiang
- a Experimental Medicine Center, The Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China.,c Department of Endocrinology , The Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
| | - Feng Chen
- a Experimental Medicine Center, The Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
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9
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Long Y, Huang C, Wu J, Cheng JN, Liang GN, Jiang CX, Wan Q. 2,3',4,4',5-Pentachlorobiphenyl impairs insulin-induced NO production partly through excessive ROS production in endothelial cells. Toxicol Mech Methods 2017; 27:592-597. [PMID: 28592194 DOI: 10.1080/15376516.2017.1337259] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Polychlorinated biphenyls (PCBs) have been reported to be associated with increased risk to hypertension, atherosclerosis, cardiovascular disease, etc. 2,3',4,4',5-Pentachlorobiphenyl, known as PCB-118, is a member of coplanar PCBs which renders their structure similar to polychlorinated dibenzo-p-dioxins (PCDDs) and has dioxin-like activity. In our current study, we investigated the effect of PCB-118 exposure on nitric oxide (NO) production and the underlying mechanisms in vitro. Exposure of PCB-118 impaired insulin-induced NO production and endothelial nitric oxide synthase (eNOS) activity in human umbilical vein endothelial cells (HUVECs) with no significant effect on cell viability. Furthermore, PCB-118 treatment induced oxidative stress. In addition, scavenging of reactive oxygen species (ROS) by 10 μM N-acetyl-l-cysteine (NAC) partly rescued impaired insulin-induced eNOS activities and NO productions induced by PCB-118 in HUVECs. Taken together, these results indicate that PCB-118 mediates lower eNOS activity and impairs insulin-induced NO production partly through excessive ROS production in endothelial cells.
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Affiliation(s)
- Yang Long
- a Department of Endocrinology , t he Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China.,b Laboratory of Endocrinology , Experimental Medicine Center, the Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
| | - Can Huang
- b Laboratory of Endocrinology , Experimental Medicine Center, the Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
| | - Jian Wu
- b Laboratory of Endocrinology , Experimental Medicine Center, the Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
| | - Jin-Nan Cheng
- c Department of Dermatology , t he Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
| | - Guan-Nan Liang
- b Laboratory of Endocrinology , Experimental Medicine Center, the Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
| | - Chun-Xia Jiang
- a Department of Endocrinology , t he Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China.,b Laboratory of Endocrinology , Experimental Medicine Center, the Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
| | - Qin Wan
- a Department of Endocrinology , t he Affiliated Hospital of Southwest Medical University , Luzhou , Sichuan , PR China
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10
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Immortalized endothelial cell lines for in vitro blood–brain barrier models: A systematic review. Brain Res 2016; 1642:532-545. [DOI: 10.1016/j.brainres.2016.04.024] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 04/05/2016] [Accepted: 04/12/2016] [Indexed: 12/18/2022]
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11
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The effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the development and function of the blood–brain barrier. Neurotoxicology 2016; 52:64-71. [DOI: 10.1016/j.neuro.2015.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 11/05/2015] [Accepted: 11/09/2015] [Indexed: 01/03/2023]
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12
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Eum SY, Jaraki D, András IE, Toborek M. Lipid rafts regulate PCB153-induced disruption of occludin and brain endothelial barrier function through protein phosphatase 2A and matrix metalloproteinase-2. Toxicol Appl Pharmacol 2015; 287:258-66. [PMID: 26080028 DOI: 10.1016/j.taap.2015.06.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 05/20/2015] [Accepted: 06/11/2015] [Indexed: 01/30/2023]
Abstract
Occludin is an essential integral transmembrane protein regulating tight junction (TJ) integrity in brain endothelial cells. Phosphorylation of occludin is associated with its localization to TJ sites and incorporation into intact TJ assembly. The present study is focused on the role of lipid rafts in polychlorinated biphenyl (PCB)-induced disruption of occludin and endothelial barrier function. Exposure of human brain endothelial cells to 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153) induced dephosphorylation of threonine residues of occludin and displacement of occludin from detergent-resistant membrane (DRM)/lipid raft fractions within 1h. Moreover, lipid rafts modulated the reduction of occludin level through activation of matrix metalloproteinase 2 (MMP-2) after 24h PCB153 treatment. Inhibition of protein phosphatase 2A (PP2A) activity by okadaic acid or fostriecin markedly protected against PCB153-induced displacement of occludin and increased permeability of endothelial cells. The implication of lipid rafts and PP2A signaling in these processes was further defined by co-immunoprecipitation of occludin with PP2A and caveolin-1, a marker protein of lipid rafts. Indeed, a significant MMP-2 activity was observed in lipid rafts and was increased by exposure to PCB153. The pretreatment of MMP-2 inhibitors protected against PCB153-induced loss of occludin and disruption of lipid raft structure prevented the increase of endothelial permeability. Overall, these results indicate that lipid raft-associated processes, such as PP2A and MMP-2 activation, participate in PCB153-induced disruption of occludin function in brain endothelial barrier. This study contributes to a better understanding of the mechanisms leading to brain endothelial barrier dysfunction in response to exposure to environmental pollutants, such as ortho-substituted PCBs.
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Affiliation(s)
- Sung Yong Eum
- Department of Biochemistry & Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | - Dima Jaraki
- Department of Biochemistry & Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Ibolya E András
- Department of Biochemistry & Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Michal Toborek
- Department of Biochemistry & Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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Szczepkowska A, Lagaraine C, Robert V, Dufourny L, Thiéry JC, Skipor J. Effect of a two-week treatment with a low dose of 2,2′4,4′,5,5′-hexachlorobiphenyl (PCB153) on tight junction protein expression in ovine choroid plexus during long and short photoperiods. Neurotoxicol Teratol 2013; 37:63-7. [DOI: 10.1016/j.ntt.2013.03.061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 03/27/2013] [Accepted: 03/28/2013] [Indexed: 01/30/2023]
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Effect of a two-week treatment with low dose of ortho-substituted polychlorinated biphenyls (PCB104 and PCB153) on VEGF-receptor system expression in the choroid plexus in adult ewes. Pol J Vet Sci 2012; 15:621-8. [DOI: 10.2478/v10181-012-0098-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Abstract
Ortho-substituted polychlorinated biphenyl (PCB) congeners, which constitute a large part of PCB residues found in the environment and in animal tissues, are known to exert potent vascular effects and can activate endothelial cells in the periphery and in the brain. The choroid plexus (CP) is responsible for cerebrospinal fluid (CSF) production and its epithelial cell layer is responsible for structure and functions of the blood-CSF barrier. The aims of this study were: 1) to investigate if environmentally relevant doses of PCB153 and similar doses of PCB104 caused changes in the expression of vascular endothelial growth factor (VEGF) - receptor system, which maintains CP function, and 2) to determine the level of both congeners in blood plasma after their oral administration. Studies of both congeners were performed on ovariectomized ewes treated per os with low doses (0.1 mg/kg, three times a week for two weeks) of PCB153 (n=4) or PCB104 (n=4) and vehicle (control, n=4). The effects of PCB153 and PCB104 treatment on mRNA expression of two isoforms of VEGF (VEGF120 and VEGF164) and their receptors Flt-1 and KDR were determined using real-time PCR. Plasma concentration of PCBs was measured using high resolution chromatography/tandem mass spectrometry (HRGC/MS-MS). We observed that neither PCB153 nor PCB104 significantly altered the mRNA of the VEGF-receptor system in the CP. In PCB treated animals plasma concentration of PCB153 (1.425 ± 0.16 ng/g of dry mass, DM) was about 150 times higher than PCB104 (0.009 ± 0.007ng/g DM). In control animals the PCB153 level was 0.14 ± 0.031 ng/g DM, while the PCB104 level was below detection level. This indicates that increase in plasma PCB153 concentration to levels similar to those reported in humans and of PCB104 concentration to levels 100 times higher than those found in human plasma did not affect the VEGF-receptor system in the CP in adult ewes. The significantly lower increase of PCB104 than PCB153 concentration in blood after oral administration suggests different absorption of both congeners from the digestive tract.
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Selvakumar K, Prabha RL, Saranya K, Bavithra S, Krishnamoorthy G, Arunakaran J. Polychlorinated biphenyls impair blood–brain barrier integrity via disruption of tight junction proteins in cerebrum, cerebellum and hippocampus of female Wistar rats. Hum Exp Toxicol 2012; 32:706-20. [DOI: 10.1177/0960327112464798] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Polychlorinated biphenyls (PCBs) comprise a ubiquitous class of toxic substances associated with carcinogenic and tumor-promoting effects as well as neurotoxic properties. Reactive oxygen species, which is produced from PCBs, alters blood–brain barrier (BBB) integrity, which is paralleled by cytoskeletal rearrangements and redistribution and disappearance of tight junction proteins (TJPs) like claudin-5 and occludin. Quercetin, a potent antioxidant present in onion and other vegetables, appears to protect brain cells against oxidative stress, a tissue-damaging process associated with Alzheimer’s and other neurodegenerative disorders. The aim of this study is to analyze the role of quercetin on oxidative stress markers and transcription of transmembrane and cytoplasmic accessory TJPs on cerebrum, cerebellum and hippocampus of female rats exposed to PCBs. Rats were divided into the following four groups. Group I: received only vehicle (corn oil) intraperitoneally (i.p.); group II: received Aroclor 1254 at a dose of 2 mg/kg body weight (bwt)/day (i.p); group III: received Aroclor 1254 (i.p.) and simultaneously quercetin 50 mg/kg bwt/day through gavage and group IV: received quercetin alone gavage. From the experiment, the levels of hydrogen peroxide, lipid peroxidation and thiobarbituric acid reactive substances were observed to increase significantly in cerebrum, cerebellum and hippocampus as 50%, 25% and 20%, respectively, after exposure to PCB, and the messenger RNA expression of TJP in rats exposed to PCBs is decreased and is retrieved to the normal level simultaneously in quercetin-treated rats. Hence, quercetin can be used as a preventive medicine to PCBs exposure and prevents neurodegenerative disorders.
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Affiliation(s)
- K. Selvakumar
- Department of Endocrinology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai, India
| | - R. Lakshmi Prabha
- Department of Endocrinology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai, India
| | - K. Saranya
- Department of Endocrinology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai, India
| | - S. Bavithra
- Department of Endocrinology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai, India
| | - G. Krishnamoorthy
- Department of Biochemistry, Asan Memorial Dental College and Hospital, Asan Nagar, Chengalpattu, India
| | - J. Arunakaran
- Department of Endocrinology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai, India
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Choi JJ, Choi YJ, Chen L, Zhang B, Eum SY, Abreu MT, Toborek M. Lipopolysaccharide potentiates polychlorinated biphenyl-induced disruption of the blood-brain barrier via TLR4/IRF-3 signaling. Toxicology 2012; 302:212-20. [PMID: 22906770 DOI: 10.1016/j.tox.2012.08.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 07/27/2012] [Accepted: 08/01/2012] [Indexed: 01/22/2023]
Abstract
Exposure to polychlorinated biphenyls (PCBs) is associated with numerous adverse health effects. Although the main route of exposure to PCBs is through the gastrointestinal tract, little is known about the contribution of the gut to the health effects of PCBs. We hypothesize that PCBs can disrupt intestinal integrity, causing lipopolysaccharide (LPS) translocation into the bloodstream and potentiation of the systemic toxicity of PCBs. C57BL/6 mice were exposed to individual PCB congeners by oral gavage, followed by the assessment of small intestine morphology and plasma levels of proinflammatory mediators. In addition, mice and human brain endothelial cells were exposed to PCB118 in the presence or absence of LPS to evaluate the contribution of LPS to PCB-induced toxicity at the blood-brain barrier (BBB) level. Oral administration of PCB153, PCB118, or PCB126 disrupted intestinal morphology and increased plasma levels of LPS and proinflammatory cytokines. Direct injection of LPS and PCB118 into the cerebral microvasculature resulted in synergistic disruption of BBB integrity and decreased expression of tight junction proteins in brain microvessels. In vitro experiments confirmed these effects and indicated that stimulation of the toll-like receptor 4 (TLR4) pathway can be responsible for these effects via activation of interferon regulatory factor-3 (IRF-3). These results indicate that LPS may be a contributing factor in PCB-induced dysfunction of the brain endothelium via stimulation of the TLR4/IRF-3 pathway.
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Affiliation(s)
- Jeong June Choi
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, Miami, FL 33136, USA
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Skipor J, Młynarczuk J, Szczepkowska A, Lagaraine C, Grochowalski A, Guillaume D, Dufourny L, Thiéry JC. Photoperiod modulates access of 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153) to the brain and its effect on gonadotropin and thyroid hormones in adult ewes. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2012; 78:336-343. [PMID: 22197259 DOI: 10.1016/j.ecoenv.2011.11.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 11/28/2011] [Accepted: 11/29/2011] [Indexed: 05/31/2023]
Abstract
The effects of photoperiod on the cerebrospinal fluid (CSF) concentration of six ortho-substituted polychlorinated biphenyls (PCBs: PCB28, PCB52, PCB101, PCB138, PCB153, and PCB180), the effects of an orally administered low dose of PCB153 (0.3mg/kg, three times a week for three weeks) on PCBs and thyroid hormones (THs) concentrations in the CSF and plasma, and the release of luteinizing hormone (LH) were determined in ovariectomized, estradiol-implanted ewes (2.5 years old) maintained indoors under artificial long day (LD, 16L: 8D) and short day (SD, 8L: 16D) conditions. Concentrations of two PCBs (PCB28 and PCB153) in the plasma and four PCBs in the CSF (PCB101, PCB138, PCB153, and PCB180) were significantly higher during LD than SD. Following PCB153 treatment, its concentration in the plasma was higher in SD (1.2 ± 0.3 ng/ml) than LD (0.2 ± 0.05 ng/ml), but similar in the CSF (10.2 ± 3.7 pg/ml vs. 13 ± 0.7 pg/ml) under both photoperiods. During SD, the concentration of PCB153 in the CSF was higher in treated animals than controls, while no differences were noted under LD. These findings indicate that in ewes, exposure of the brain to more highly chlorinated, ortho-substituted PCBs may be modulated by photoperiod. PCB153 treatment had no effect on plasma THs, but reduced total triiodothyronine concentration during LD and free thyroxine during SD in the CSF. Under both photoperiods, PCB153 reduced basal plasma LH and reinforced the inhibition of pulsatile LH release during LD. As PCB153 reduced LH and THs (which are involved in the seasonal control of reproduction in ewes), it may have a braking effect on seasonal transitions between active and inactive phases of reproduction.
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Affiliation(s)
- Janina Skipor
- Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland.
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Zougbédé S, Miller F, Ravassard P, Rebollo A, Cicéron L, Couraud PO, Mazier D, Moreno A. Metabolic acidosis induced by Plasmodium falciparum intraerythrocytic stages alters blood-brain barrier integrity. J Cereb Blood Flow Metab 2011; 31:514-26. [PMID: 20683453 PMCID: PMC3049507 DOI: 10.1038/jcbfm.2010.121] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The pathogenesis of cerebral malaria (CM) remains largely unknown. There is growing evidence that combination of both parasite and host factors could be involved in blood-brain barrier (BBB) breakdown. However, lack of adequate in vitro model of human BBB so far hampered molecular studies. In this article, we propose the use of hCMEC/D3 cells, a well-established human cerebral microvascular endothelial cell (EC) line, to study BBB breakdown induced by Plasmodium falciparum-parasitized red blood cells and environmental conditions. We show that coculture of parasitized erythrocytes with hCMEC/D3 cells induces cell adhesion and paracellular permeability increase, which correlates with disorganization of zonula occludens protein 1 expression pattern. Permeability increase and modification of tight junction proteins distribution are cytoadhesion independent. Finally, we show that permeability of hCMEC/D3 cell monolayers is mediated through parasite induced metabolic acidosis, which in turns correlates with apoptosis of parasitized erythrocytes. This new coculture model represents a very useful tool, which will improve the knowledge of BBB breakdown and the development of adjuvant therapies, together with antiparasitic drugs.
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Choi YJ, Seelbach MJ, Pu H, Eum SY, Chen L, Zhang B, Hennig B, Toborek M. Polychlorinated biphenyls disrupt intestinal integrity via NADPH oxidase-induced alterations of tight junction protein expression. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:976-81. [PMID: 20299304 PMCID: PMC2920918 DOI: 10.1289/ehp.0901751] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 03/18/2010] [Indexed: 05/09/2023]
Abstract
BACKGROUND Polychlorinated biphenyls (PCBs) are widely distributed environmental toxicants that contribute to numerous disease states. The main route of exposure to PCBs is through the gastrointestinal tract; however, little is known about the effects of PCBs on intestinal epithelial barrier functions. OBJECTIVE The aim of the present study was to address the hypothesis that highly chlorinated PCBs can disrupt gut integrity at the level of tight junction (TJ) proteins. METHODS Caco-2 human colon adenocarcinoma cells were exposed to one of the following PCB congeners: PCB153, PCB118, PCB104, and PCB126. We then assessed NAD(P)H oxidase (NOX) activity and expression and the barrier function of Caco-2 cells. In addition, the integrity of intestinal barrier function and expression of TJ proteins were evaluated in C57BL/6 mice exposed to individual PCBs by oral gavage. RESULTS Exposure of Caco-2 cells to individual PCB congeners resulted in activation of NOX and increased permeability of fluorescein isothiocyanate (FITC)-labeled dextran (4 kDa). Treatment with PCB congeners also disrupted expression of TJ proteins zonula occludens-1 (ZO-1) and occludin in Caco-2 cells. Importantly, inhibition of NOX by apocynin significantly protected against PCB-mediated increase in epithelial permeability and alterations of ZO-1 protein expression. Exposure to PCBs also resulted in alterations of gut permeability via decreased expression of TJ proteins in an intact physiological animal model. CONCLUSIONS These results suggest that oral exposure to highly chlorinated PCBs disrupts intestinal epithelial integrity and may directly contribute to the systemic effects of these toxicants.
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Affiliation(s)
- Yean Jung Choi
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery and
| | - Melissa J. Seelbach
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery and
| | - Hong Pu
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery and
| | - Sung Yong Eum
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery and
| | - Lei Chen
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery and
| | - Bei Zhang
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery and
| | - Bernhard Hennig
- College of Agriculture, University of Kentucky, Lexington, Kentucky, USA
| | - Michal Toborek
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery and
- Address correspondence to M. Toborek, Department of Neurosurgery, Molecular Neuroscience and Vascular Biology Laboratory, University of Kentucky Medical Center, 593 Wethington Bldg., 900 S. Limestone, Lexington, KY 40536 USA. Telephone: (859) 323-4094. Fax: (859) 323-2705. E-mail:
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Han SG, Eum SY, Toborek M, Smart E, Hennig B. Polychlorinated biphenyl-induced VCAM-1 expression is attenuated in aortic endothelial cells isolated from caveolin-1 deficient mice. Toxicol Appl Pharmacol 2010; 246:74-82. [PMID: 20406653 DOI: 10.1016/j.taap.2010.04.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 04/09/2010] [Accepted: 04/12/2010] [Indexed: 12/13/2022]
Abstract
Exposure to environmental contaminants, such as polychlorinated biphenyls (PCBs), is a risk factor for the development of cardiovascular diseases such as atherosclerosis. Vascular cell adhesion molecule-1 (VCAM-1) is a critical mediator for adhesion and uptake of monocytes across the endothelium in the early stages of atherosclerosis development. The upregulation of VCAM-1 by PCBs may be dependent on functional membrane domains called caveolae. Caveolae are particularly abundant in endothelial cell membranes and involved in trafficking and signal transduction. The objective of this study was to investigate the role of caveolae in PCB-induced endothelial cell dysfunction. Primary mouse aortic endothelial cells (MAECs) isolated from caveolin-1-deficient mice and background C57BL/6 mice were treated with coplanar PCBs, such as PCB77 and PCB126. In addition, siRNA gene silencing technique was used to knockdown caveolin-1 in porcine vascular endothelial cells. In MAECs with functional caveolae, VCAM-1 protein levels were increased after exposure to both coplanar PCBs, whereas expression levels of VCAM-1 were not significantly altered in cells deficient of caveolin-1. Furthermore, PCB-induced monocyte adhesion was attenuated in caveolin-1-deficient MAECs. Similarly, siRNA silencing of caveolin-1 in porcine endothelial cells confirmed the caveolin-1-dependent VCAM-1 expression. Treatment of cells with PCB77 and PCB126 resulted in phosphorylation of extracellular signal-regulated kinase-1/2 (ERK1/2), and pharmacological inhibition of ERK1/2 diminished the observed PCB-induced increase in monocyte adhesion. These findings suggest that coplanar PCBs induce adhesion molecule expression, such as VCAM-1, in endothelial cells, and that this response is regulated by caveolin-1 and functional caveolae. Our data demonstrate a critical role of functional caveolae in the activation and dysfunction of endothelial cells by coplanar PCBs.
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Affiliation(s)
- Sung Gu Han
- Molecular and Cell Nutrition Laboratory, College of Agriculture, University of Kentucky, Lexington, KY 40536, USA
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Seelbach M, Chen L, Powell A, Choi YJ, Zhang B, Hennig B, Toborek M. Polychlorinated biphenyls disrupt blood-brain barrier integrity and promote brain metastasis formation. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:479-84. [PMID: 20064788 PMCID: PMC2854723 DOI: 10.1289/ehp.0901334] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2009] [Accepted: 10/28/2009] [Indexed: 05/14/2023]
Abstract
BACKGROUND Polychlorinated biphenyls (PCBs) comprise a ubiquitous class of toxic substances associated with carcinogenic and tumor-promoting effects as well as neurotoxic properties in the brain. However, the effects of PCBs on the development of tumor metastases are not fully understood. OBJECTIVE We evaluated the hypothesis that exposure to individual PCB congeners can facilitate the development of brain metastases in immunocompetent mice via the disruption of the integrity of the blood-brain barrier (BBB). METHODS C57/Bl6 mice were exposed to individual PCBs by oral gavage, and 48 hr later they were injected with luciferase-labeled K1735 M2 melanoma cells into the internal carotid artery. The development of metastatic nodules was monitored by bioluminescent imaging. In addition, we evaluated the functional permeability of the BBB by measuring permeability of sodium fluorescein across the brain microvessels. Expression and colocalization of tight junction (TJ) proteins were studied by Western blotting and immunofluorescence microscopy. RESULTS Oral administration of coplanar PCB126, mono-ortho-substituted PCB118, and non-coplanar PCB153 (each at 150 micromol/kg body weight) differentially altered expression of the TJ proteins claudin-5, occludin, and zonula occludens-1 in brain capillaries. These alterations were associated with increased permeability of the BBB. Most importantly, exposure to individual PCB congeners enhanced the rate of formation and progression of brain metastases of luciferase-tagged melanoma cells. CONCLUSIONS Our results show for the first time that exposure to individual PCBs can facilitate the formation of bloodborne metastases via alterations of the integrity of the brain capillary endothelium.
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Affiliation(s)
- Melissa Seelbach
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky Medical Center, Lexington, Kentucky, USA
| | - Lei Chen
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky Medical Center, Lexington, Kentucky, USA
| | - Anita Powell
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky Medical Center, Lexington, Kentucky, USA
| | - Yean Jung Choi
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky Medical Center, Lexington, Kentucky, USA
| | - Bei Zhang
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky Medical Center, Lexington, Kentucky, USA
| | - Bernhard Hennig
- Molecular and Cell Nutrition Laboratory, College of Agriculture, University of Kentucky, Lexington, Kentucky, USA
| | - Michal Toborek
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky Medical Center, Lexington, Kentucky, USA
- Address correspondence to M. Toborek, Department of Neurosurgery, Molecular Neuroscience and Vascular Biology Laboratory, University of Kentucky Medical Center, 593 Wethington Building, 900 South Limestone, Lexington, KY 40536 USA. Telephone: (859) 323-4094. Fax: (859) 323-2705. E-mail:
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McCall IC, Betanzos A, Weber DA, Nava P, Miller GW, Parkos CA. Effects of phenol on barrier function of a human intestinal epithelial cell line correlate with altered tight junction protein localization. Toxicol Appl Pharmacol 2009; 241:61-70. [PMID: 19679145 DOI: 10.1016/j.taap.2009.08.002] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 07/14/2009] [Accepted: 08/03/2009] [Indexed: 01/11/2023]
Abstract
Phenol contamination of soil and water has raised concerns among people living near phenol-producing factories and hazardous waste sites containing the chemical. Phenol, particularly in high concentrations, is an irritating and corrosive substance, making mucosal membranes targets of toxicity in humans. However, few data on the effects of phenol after oral exposure exist. We used an in vitro model employing human intestinal epithelial cells (SK-CO15) cultured on permeable supports to examine effects of phenol on epithelial barrier function. We hypothesized that phenol disrupts epithelial barrier by altering tight junction (TJ) protein expression. The dose-response effect of phenol on epithelial barrier function was determined using transepithelial electrical resistance (TER) and FITC-dextran permeability measurements. We studied phenol-induced changes in cell morphology and expression of several tight junction proteins by immunofluorescence and Western blot analysis. Effects on cell viability were assessed by MTT, Trypan blue, propidium iodide and TUNEL staining. Exposure to phenol resulted in decreased TER and increased paracellular flux of FITC-dextran in a dose-dependent manner. Delocalization of claudin-1 and ZO-1 from TJs to cytosol correlated with the observed increase in permeability after phenol treatment. Additionally, the decrease in TER correlated with changes in the distribution of a membrane raft marker, suggesting phenol-mediated effects on membrane fluidity. Such observations were independent of effects of phenol on cell viability as enhanced permeability occurred at doses of phenol that did not cause cell death. Overall, these findings suggest that phenol may affect transiently the lipid bilayer of the cell membrane, thus destabilizing TJ-containing microdomains.
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Affiliation(s)
- Ingrid C McCall
- Department of Environmental and Occupational Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
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Eum SY, Andras I, Hennig B, Toborek M. NADPH oxidase and lipid raft-associated redox signaling are required for PCB153-induced upregulation of cell adhesion molecules in human brain endothelial cells. Toxicol Appl Pharmacol 2009; 240:299-305. [PMID: 19632255 DOI: 10.1016/j.taap.2009.07.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2009] [Revised: 07/17/2009] [Accepted: 07/20/2009] [Indexed: 01/24/2023]
Abstract
Exposure to persistent organic pollutants, such as polychlorinated biphenyls (PCBs), can lead to chronic inflammation and the development of vascular diseases. Because cell adhesion molecules (CAMs) of the cerebrovascular endothelium regulate infiltration of inflammatory cells into the brain, we have explored the molecular mechanisms by which ortho-substituted polychlorinated biphenyls (PCBs), such as PCB153, can upregulate CAMs in brain endothelial cells. Exposure to PCB153 increased expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), as well as elevated adhesion of leukocytes to brain endothelial cells. These effects were impeded by inhibitors of EGFR, JAKs, or Src activity. In addition, pharmacological inhibition of NADPH oxidase or disruption of lipid rafts by cholesterol depleting agents blocked PCB153-induced phosphorylation of JAK and Src kinases and upregulation of CAMs. In contrast, silencing of caveolin-1 by siRNA interference did not affect upregulation of ICAM-1 and VCAM-1 in brain endothelial cells stimulated by PCB153. Results of the present study indicate that lipid raft-dependent NADPH oxidase/JAK/EGFR signaling mechanisms regulate the expression of CAMs in brain endothelial cells and adhesion of leukocytes to endothelial monolayers. Due to its role in leukocyte infiltration, induction of CAMs may contribute to PCB-induced cerebrovascular disorders and neurotoxic effects in the CNS.
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Affiliation(s)
- Sung Yong Eum
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky, Lexington, KY 40536, USA.
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Helyar SG, Patel B, Headington K, El Assal M, Chatterjee PK, Pacher P, Mabley JG. PCB-induced endothelial cell dysfunction: role of poly(ADP-ribose) polymerase. Biochem Pharmacol 2009; 78:959-65. [PMID: 19549508 DOI: 10.1016/j.bcp.2009.06.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 06/11/2009] [Accepted: 06/15/2009] [Indexed: 12/14/2022]
Abstract
Polychlorinated biphenyls (PCBs) are persistent environmental pollutants implicated in the development of pro-inflammatory events critical in the pathology of atherosclerosis and cardiovascular disease. PCB exposure of endothelial cells results in increased cellular oxidative stress, activation of stress and inflammatory pathways leading to increased expression of cytokines and adhesion molecules and ultimately cell death, all of which can lead to development of atherosclerosis. To date no studies have been performed to examine the direct effects of PCB exposure on the vasculature relaxant response which if impaired may predispose individuals to hypertension, an additional risk factor for atherosclerosis. Overactivation of the DNA repair enzyme poly(ADP-ribose) polymerase (PARP) following oxidative/nitrosative stress in endothelial cells and subsequent depletion of NADPH has been identified as a central mediator of cellular dysfunction. The aim therefore was to investigate whether 2,2',4,6,6'-pentachlorobiphenyl (PCB 104) directly causes endothelial cell dysfunction via increased oxidative stress and subsequent overactivation of PARP. Exposure of ex vivo rat aortic rings to PCB 104 impaired the acetylcholine-mediated relaxant response, an effect that was dependent on both concentration and exposure time. In vitro exposure of mouse endothelial cells to PCB 104 resulted in increased cellular oxidative stress through activation of the cytochrome p450 enzyme CYP1A1 with subsequent overactivation of PARP and NADPH depletion. Pharmacological inhibition of CYP1A1 or PARP protected against the PCB 104-mediated endothelial cell dysfunction. In conclusion, the environmental contaminants, PCBs, can activate PARP directly impairing endothelial cell function that may predispose exposed individuals to development of hypertension and cardiovascular disease.
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Affiliation(s)
- Simon G Helyar
- Brighton and Sussex Medical School, Falmer, Brighton BN1 9PH, UK
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2,2′,4,4′,5,5′-Hexachlorobiphenyl (PCB 153) induces degradation of adherens junction proteins and inhibits β-catenin-dependent transcription in liver epithelial cells. Toxicology 2009; 260:104-11. [DOI: 10.1016/j.tox.2009.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 03/17/2009] [Accepted: 03/18/2009] [Indexed: 12/16/2022]
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