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Abu-Bakar A, Ismail M, Zulkifli MZI, Zaini NAS, Shukor NIA, Harun S, Inayat-Hussain SH. Mapping the influence of hydrocarbons mixture on molecular mechanisms, involved in breast and lung neoplasms: in silico toxicogenomic data-mining. Genes Environ 2024; 46:15. [PMID: 38982523 PMCID: PMC11232146 DOI: 10.1186/s41021-024-00310-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 06/07/2024] [Indexed: 07/11/2024] Open
Abstract
BACKGROUND Exposure to chemical mixtures inherent in air pollution, has been shown to be associated with the risk of breast and lung cancers. However, studies on the molecular mechanisms of exposure to a mixture of these pollutants, such as hydrocarbons, in the development of breast and lung cancers are scarce. We utilized in silico toxicogenomic analysis to elucidate the molecular pathways linked to both cancers that are influenced by exposure to a mixture of selected hydrocarbons. The Comparative Toxicogenomics Database and Cytoscape software were used for data mining and visualization. RESULTS Twenty-five hydrocarbons, common in air pollution with carcinogenicity classification of 1 A/B or 2 (known/presumed or suspected human carcinogen), were divided into three groups: alkanes and alkenes, halogenated hydrocarbons, and polyaromatic hydrocarbons. The in silico data-mining revealed 87 and 44 genes commonly interacted with most of the investigated hydrocarbons are linked to breast and lung cancer, respectively. The dominant interactions among the common genes are co-expression, physical interaction, genetic interaction, co-localization, and interaction in shared protein domains. Among these genes, only 16 are common in the development of both cancers. Benzo(a)pyrene and tetrachlorodibenzodioxin interacted with all 16 genes. The molecular pathways potentially affected by the investigated hydrocarbons include aryl hydrocarbon receptor, chemical carcinogenesis, ferroptosis, fluid shear stress and atherosclerosis, interleukin 17 signaling pathway, lipid and atherosclerosis, NRF2 pathway, and oxidative stress response. CONCLUSIONS Within the inherent limitations of in silico toxicogenomics tools, we elucidated the molecular pathways associated with breast and lung cancer development potentially affected by hydrocarbons mixture. Our findings indicate adaptive responses to oxidative stress and inflammatory damages are instrumental in the development of both cancers. Additionally, ferroptosis-a non-apoptotic programmed cell death driven by lipid peroxidation and iron homeostasis-was identified as a new player in these responses. Finally, AHR potential involvement in modulating IL-8, a critical gene that mediates breast cancer invasion and metastasis to the lungs, was also highlighted. A deeper understanding of the interplay between genes associated with these pathways, and other survival signaling pathways identified in this study, will provide invaluable knowledge in assessing the risk of inhalation exposure to hydrocarbons mixture. The findings offer insights into future in vivo and in vitro laboratory investigations that focus on inhalation exposure to the hydrocarbons mixture.
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Affiliation(s)
- A'edah Abu-Bakar
- Product Stewardship and Toxicology, Environment, Social Performance & Product Stewardship (ESPPS), Group Health, Safety and Environment (GHSE), Petroliam Nasional Berhad (PETRONAS), Kuala Lumpur, 50088, Malaysia.
| | - Maihani Ismail
- Product Stewardship and Toxicology, Environment, Social Performance & Product Stewardship (ESPPS), Group Health, Safety and Environment (GHSE), Petroliam Nasional Berhad (PETRONAS), Kuala Lumpur, 50088, Malaysia.
| | - M Zaqrul Ieman Zulkifli
- Product Stewardship and Toxicology, Environment, Social Performance & Product Stewardship (ESPPS), Group Health, Safety and Environment (GHSE), Petroliam Nasional Berhad (PETRONAS), Kuala Lumpur, 50088, Malaysia
| | - Nur Aini Sofiyya Zaini
- Product Stewardship and Toxicology, Environment, Social Performance & Product Stewardship (ESPPS), Group Health, Safety and Environment (GHSE), Petroliam Nasional Berhad (PETRONAS), Kuala Lumpur, 50088, Malaysia
| | - Nur Izzah Abd Shukor
- Health, Safety and Environment (HSE), KLCC Urusharta, Kuala Lumpur, 50088, Malaysia
| | - Sarahani Harun
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, Bangi, Selangor, 43600 UKM, Malaysia
| | - Salmaan Hussain Inayat-Hussain
- ESPPS, GHSE, PETRONAS, Kuala Lumpur, 50088, Malaysia
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College St, New Haven, CT, 06250, USA
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Choudhury SR, Byrum SD, Blossom SJ. Trichloroethylene metabolite modulates DNA methylation-dependent gene expression in Th1-polarized CD4+ T cells from autoimmune-prone mice. Toxicol Sci 2024; 199:289-300. [PMID: 38518092 PMCID: PMC11131021 DOI: 10.1093/toxsci/kfae032] [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] [Indexed: 03/24/2024] Open
Abstract
Trichloroethylene (TCE) is an industrial solvent and widespread environmental contaminant associated with CD4+ T-cell activation and autoimmune disease. Prior studies showed that exposure to TCE in the drinking water of autoimmune-prone mice expanded effector/memory CD4+ T cells with an interferon-γ (IFN-γ)-secreting Th1-like phenotype. However, very little is known how TCE exposure skews CD4+ T cells towards this pro-inflammatory Th1 subset. As observed previously, TCE exposure was associated with hypermethylation of regions of the genome related to transcriptional repression in purified effector/memory CD4 T cells. We hypothesized that TCE modulates transcriptional and/or epigenetic programming of CD4+ T cells as they differentiate from a naive to effector phenotype. In the current study, purified naive CD4 T cells from both male and female autoimmune-prone MRL/MpJ mice were activated ex vivo and polarized towards a Th1 subset for 4 days in the presence or absence of the oxidative metabolite of TCE, trichloroacetaldehyde hydrate (TCAH) in vitro. An RNA-seq assessment and reduced representation bisulfite sequencing for DNA methylation were conducted on Th1 cells or activated, non-polarized cells. The results demonstrated TCAH's ability to regulate key genes involved in the immune response and autoimmunity, including Ifng, by altering the level of DNA methylation at the gene promoter. Intriguing sex differences were observed and for the most part, the effects were more robust in females compared to males. In conclusion, TCE via TCAH epigenetically regulates gene expression in CD4+ T cells. These results may have implications for mechanistic understanding or future therapeutics for autoimmunity.
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Affiliation(s)
- Samrat Roy Choudhury
- Division of Hematology/Oncology, Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72202, USA
- Arkansas Children’s Research Institute, Department of Pediatrics, Little Rock, Arkansas 72202, USA
| | - Stephanie D Byrum
- Arkansas Children’s Research Institute, Department of Pediatrics, Little Rock, Arkansas 72202, USA
- Department of Biochemistry & Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
| | - Sarah J Blossom
- Department of Pharmaceutical Sciences, University of New Mexico, Albuquerque, New Mexico 87131, USA
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3
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Blossom SJ, Melnyk SB, Simmen FA. Complex epigenetic patterns in cerebellum generated after developmental exposure to trichloroethylene and/or high fat diet in autoimmune-prone mice. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:583-594. [PMID: 31894794 PMCID: PMC7350281 DOI: 10.1039/c9em00514e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Trichloroethylene (TCE) is an environmental contaminant associated with immune-mediated inflammatory disorders and neurotoxicity. Based on known negative effects of developmental overnutrition on neurodevelopment, we hypothesized that developmental exposure to high fat diet (HFD) consisting of 40% kcal fat would enhance neurotoxicity of low-level (6 μg per kg per day) TCE exposure in offspring over either stressor alone. Male offspring were evaluated at ∼6 weeks of age after exposure beginning 4 weeks preconception in the dams until weaning. TCE, whether used as a single exposure or together with HFD, appeared to be more robust than HFD alone in altering one-carbon metabolites involved in glutathione redox homeostasis and methylation capacity. In contrast, opposing effects of expression of key enzymes related to DNA methylation related to HFD and TCE exposure were observed. The mice generated unique patterns of anti-brain antibodies detected by western blotting attributable to both TCE and HFD. Taken together, developmental exposure to TCE and/or HFD appear to act in complex ways to alter brain biomarkers in offspring.
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Affiliation(s)
- Sarah J Blossom
- Department of Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children's Research Institute, Little Rock, AR 72202, USA.
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Perera BP, Faulk C, Svoboda LK, Goodrich JM, Dolinoy DC. The role of environmental exposures and the epigenome in health and disease. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2020; 61:176-192. [PMID: 31177562 PMCID: PMC7252203 DOI: 10.1002/em.22311] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/29/2019] [Accepted: 06/03/2019] [Indexed: 05/02/2023]
Abstract
The genetic material of every organism exists within the context of regulatory networks that govern gene expression, collectively called the epigenome. Epigenetics has taken center stage in the study of diseases such as cancer and diabetes, but its integration into the field of environmental health is still emerging. As the Environmental Mutagenesis and Genomics Society (EMGS) celebrates its 50th Anniversary this year, we have come together to review and summarize the seminal advances in the field of environmental epigenomics. Specifically, we focus on the role epigenetics may play in multigenerational and transgenerational transmission of environmentally induced health effects. We also summarize state of the art techniques for evaluating the epigenome, environmental epigenetic analysis, and the emerging field of epigenome editing. Finally, we evaluate transposon epigenetics as they relate to environmental exposures and explore the role of noncoding RNA as biomarkers of environmental exposures. Although the field has advanced over the past several decades, including being recognized by EMGS with its own Special Interest Group, recently renamed Epigenomics, we are excited about the opportunities for environmental epigenetic science in the next 50 years. Environ. Mol. Mutagen. 61:176-192, 2020. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Bambarendage P.U. Perera
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan
| | - Christopher Faulk
- Department of Animal Sciences, University of Minnesota, St. Paul, Minnesota
| | - Laurie K. Svoboda
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan
| | - Jaclyn M. Goodrich
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan
| | - Dana C. Dolinoy
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan
- Correspondence to: Dana C. Dolinoy, Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan.
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Byrum SD, Washam CL, Patterson JD, Vyas KK, Gilbert KM, Blossom SJ. Continuous Developmental and Early Life Trichloroethylene Exposure Promoted DNA Methylation Alterations in Polycomb Protein Binding Sites in Effector/Memory CD4 + T Cells. Front Immunol 2019; 10:2016. [PMID: 31555266 PMCID: PMC6724578 DOI: 10.3389/fimmu.2019.02016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 08/08/2019] [Indexed: 12/17/2022] Open
Abstract
Trichloroethylene (TCE) is an industrial solvent and drinking water pollutant associated with CD4+ T cell-mediated autoimmunity. In our mouse model, discontinuation of TCE exposure during adulthood after developmental exposure did not prevent immunotoxicity. To determine whether persistent effects were linked to epigenetic changes we conducted whole genome reduced representation bisulfite sequencing (RRBS) to evaluate methylation of CpG sites in autosomal chromosomes in activated effector/memory CD4+ T cells. Female MRL+/+ mice were exposed to vehicle control or TCE in the drinking water from gestation until ~37 weeks of age [postnatal day (PND) 259]. In a subset of mice, TCE exposure was discontinued at ~22 weeks of age (PND 154). At PND 259, RRBS assessment revealed more global methylation changes in the continuous exposure group vs. the discontinuous exposure group. A majority of the differentially methylated CpG regions (DMRs) across promoters, islands, and regulatory elements were hypermethylated (~90%). However, continuous developmental TCE exposure altered the methylation of 274 CpG sites in promoters and CpG islands. In contrast, only 4 CpG island regions were differentially methylated (hypermethylated) in the discontinuous group. Interestingly, 2 of these 4 sites were also hypermethylated in the continuous exposure group, and both of these island regions are associated with lysine 27 on histone H3 (H3K27) involved in polycomb complex-dependent transcriptional repression via H3K27 tri-methylation. CpG sites were overlapped with the Open Regulatory Annotation database. Unlike the discontinuous group, continuous TCE treatment resulted in 129 DMRs including 12 unique transcription factors and regulatory elements; 80% of which were enriched for one or more polycomb group (PcG) protein binding regions (i.e., SUZ12, EZH2, JARID2, and MTF2). Pathway analysis of the DMRs indicated that TCE primarily altered the methylation of genes associated with regulation of cellular metabolism and cell signaling. The results demonstrated that continuous developmental exposure to TCE differentially methylated binding sites of PcG proteins in effector/memory CD4+ cells. There were minimal yet potentially biologically significant effects that occurred when exposure was discontinued. These results point toward a novel mechanism by which chronic developmental TCE exposure may alter terminally differentiated CD4+ T cell function in adulthood.
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Affiliation(s)
- Stephanie D Byrum
- Department of Biochemistry and Molecular Biology, Arkansas Children's Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Charity L Washam
- Department of Biochemistry and Molecular Biology, Arkansas Children's Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - John D Patterson
- College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Kanan K Vyas
- Department of Pediatrics, Arkansas Children's Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Kathleen M Gilbert
- Department of Microbiology and Immunology, Arkansas Children's Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Sarah J Blossom
- Department of Pediatrics, Arkansas Children's Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR, United States
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Pan Y, Hou X, Meng Q, Yang X, Shang L, Wei X, Hao W. The critical role for TAK1 in trichloroethylene-induced contact hypersensitivity in vivo and in CD4 + T cell function alteration by trichloroethylene and its metabolites in vitro. Toxicol Appl Pharmacol 2019; 380:114705. [PMID: 31400415 DOI: 10.1016/j.taap.2019.114705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 07/22/2019] [Accepted: 08/06/2019] [Indexed: 12/20/2022]
Abstract
Occupational exposure to trichloroethylene (TCE) has been associated with severe, generalized contact hypersensitivity (CHS) skin disorder, which is considered a delayed-type hypersensitivity reaction mediated by antigen-specific T cells. Transforming growth factor-β activated kinase-1 (TAK1) is essential for regulating the development and effector function of T cells. We hypothesized that disrupting TAK1 activity might inhibit TCE-induced CHS response. In this study, a local lymph node assay was employed to build a CHS model induced by TCE combined with the inducible-TAK1 deletion system to study the effect of TAK1 on it. It was observed that TAK1 deficiency ameliorated the TCE-induced CHS response and was associated with defective T cell expansion and activation and IFN-γ production in vivo. Furthermore, we investigated the effects of TCE and its metabolites trichloroacetic acid (TCA) and dichloroacetic acid (DCA) on CD4+ T cell function and the effect of TAK1 on it in vitro. The results showed that TCE, TCA and DCA augmented the proliferation, activation and differentiation of CD4+ T cells through Jnk MAPK and NF-κB pathways. TAK1 deletion significantly attenuated these effects induced by TCE, TCA or DCA on CD4+ T cells. In conclusion, it is suggested that TAK1 plays a critical role both in TCE-induced CHS response in vivo and in TCE and its metabolite-induced CD4+ T cell activation in vitro. Local inhibition of TAK1 might offer a promising alternative feasible strategy for TCE-induced CHS.
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Affiliation(s)
- Yao Pan
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Beijing 100191, China; Department of Cosmetics, School of Science, Beijing Technology and Business University, Beijing 100048, China
| | - Xiaohong Hou
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Beijing 100191, China
| | - Qinghe Meng
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Beijing 100191, China
| | - Xiaohua Yang
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Beijing 100191, China
| | - Lanqin Shang
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Beijing 100191, China
| | - Xuetao Wei
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Beijing 100191, China
| | - Weidong Hao
- Department of Toxicology, School of Public Health, Peking University, Beijing 100191, China; Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, Beijing 100191, China.
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7
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Li W, Liu X, Yang X, Chen Y, Pang Y, Qi G, Chen L, Zhuang Z. Effect of trichloroacetaldehyde on the activation of CD4 +T cells in occupational medicamentosa-like dermatitis: An in vivo and in vitro study. Toxicology 2019; 423:95-104. [PMID: 31150805 DOI: 10.1016/j.tox.2019.05.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 05/16/2019] [Accepted: 05/27/2019] [Indexed: 01/21/2023]
Abstract
Occupational medicamentosa-like dermatitis induced by trichloroethylene (OMLDT) is a hypersensitivity disease with autoimmune liver injury, which has increasingly become a serious occupational health problem in China. However, the pathogenesis of OMLDT remained undefined. In this study, 30 TCE-induced OMLDT patients, 58 exposure controls, and 40 non-exposure controls were recruited. We showed that the ratio of activated CD4+ T cells (downregulation of CD62 L) was dramatically increased in OMLDT patients compared to exposure and non-exposure control, suggesting that CD4+ T cells activation was a key cellular event in the development of OMLDT. In parallel, the expression of cytokine including IL-2, IFN-γ, TNF-α and IL-17A were increased obviously and IL-4 decreased in CD4+ T cells from OMLDT patients. in vitro assay, we found that trichloroethylene metabolites trichloroacetaldehyde (TCAH), not trichloroacetic acid (TCA) or Trichloroethanol (TCOH) could activate the naïve CD4+ T cells characterized by a rise in intracellular calcium, down-regulated CD62 L and subsequently trigger the secretion of IL-2, IFN-γ and TNF-α. Notably, the phosphorylation status of NF-κB and p38MAPK were elevated in OMLDT patients. Moreover, TCAH also could activate the p38MAPK and NF-κB, suggesting the role of p38MAPK and NF-κB pathways in the activation of CD4+ T cells. In addition, we found that the inhibition of Schiff base formation decreased the ability of TCAH to induce the activation of naïve CD4+ T cells and p38MAPK and NF-κB pathway. In conclusion, we revealed that the CD4+ T activation and increased the cytokines including IL-2, IFN-γ and TNF-α but decreased IL-4 in CD4+ T cells were associated with OMLDT. TCAH could activate naïve CD4+ T cells through NF-κB and p38MAPK activation induced by Schiff base formation, which might contribute to the development of OMLDT. These findings provide a new insight into the pathogenesis of OMLDT.
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Affiliation(s)
- Wenxue Li
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China; Department of Toxicology, Guangzhou Center for Disease Control and Prevention, Guangzhou, 510440, China.
| | - Xiaoling Liu
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China
| | - Xueqin Yang
- Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, 518020, China
| | - Yaping Chen
- School of Pharmaceutical Sciences and Yunnan Provincial Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, 650500, China
| | - Yaqin Pang
- Faculty of Toxicology, School of Public Health, Youjiang Medical College for Nationalities, Guangxi, China
| | - Guangzi Qi
- Faculty of Toxicology, School of Public Health, Youjiang Medical College for Nationalities, Guangxi, China
| | - Liping Chen
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China.
| | - Zhixiong Zhuang
- Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, China.
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Blossom SJ, Fernandes L, Bai S, Khare S, Gokulan K, Yuan Y, Dewall M, Simmen FA, Gilbert KM. Opposing Actions of Developmental Trichloroethylene and High-Fat Diet Coexposure on Markers of Lipogenesis and Inflammation in Autoimmune-Prone Mice. Toxicol Sci 2018; 164:313-327. [PMID: 29669109 PMCID: PMC6016708 DOI: 10.1093/toxsci/kfy091] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Trichloroethylene (TCE) is a widespread environmental pollutant associated with immunotoxicity and autoimmune disease. Previous studies showed that mice exposed from gestation through early life demonstrated CD4+ T cell alterations and autoimmune hepatitis. Determining the role of one environmental risk factor for any disease is complicated by the presence of other stressors. Based on its known effects, we hypothesized that developmental overnutrition in the form of a moderately high-fat diet (HFD) consisting of 40% kcal fat would exacerbate the immunotoxicity and autoimmune-promoting effects of low-level (<10 μg/kg/day) TCE in autoimmune-prone MRL+/+ mice over either stressor alone. When female offspring were evaluated at 27 weeks of age we found that a continuous exposure beginning at 4 weeks preconception in the dams until 10 weeks of age in offspring that TCE and HFD promoted unique effects that were often antagonistic. For a number of adiposity endpoints, TCE significantly reversed the expected effects of HFD on expression of genes involved in fatty acid synthesis/insulin resistance, as well as mean pathology scores of steatosis. Although none of the animals developed pathological signs of autoimmune hepatitis, the mice generated unique patterns of antiliver antibodies detected by western blotting attributable to TCE exposure. A majority of cytokines in liver, gut, and splenic CD4+ T cells were significantly altered by TCE, but not HFD. Levels of bacterial populations in the intestinal ileum were also altered by TCE exposure rather than HFD. Thus, in contrast to our expectations this coexposure did not promote synergistic effects.
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Affiliation(s)
- Sarah J Blossom
- Department of Pediatrics, Arkansas Children’s Research Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72202
| | - Lorenzo Fernandes
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Shasha Bai
- Department of Pediatrics, Arkansas Children’s Research Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72202
| | - Sangeeta Khare
- Division of Microbiology, National Center for Toxicological Research, U.S. FDA, Jefferson, Arkansas 72079
| | - Kuppan Gokulan
- Division of Microbiology, National Center for Toxicological Research, U.S. FDA, Jefferson, Arkansas 72079
| | | | | | - Frank A Simmen
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Kathleen M Gilbert
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
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Xueqin Y, Wenxue L, Peimao L, Wen Z, Xianqing H, Zhixiong Z. Cytokine expression and cytokine-based T-cell profiling in occupational medicamentosa-like dermatitis due to trichloroethylene. Toxicol Lett 2018; 288:129-135. [DOI: 10.1016/j.toxlet.2018.02.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 01/31/2018] [Accepted: 02/08/2018] [Indexed: 12/27/2022]
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10
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Lu W, Chen Z, Ren X, Liu W, Deng R, Yuan J, Huang X, Zhu W, Liu J. SET promotes H2Ak9 acetylation by suppressing HDAC1 in trichloroethylene-induced hepatic cytotoxicity. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2018; 59:125-131. [PMID: 29579541 DOI: 10.1016/j.etap.2018.03.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/13/2018] [Accepted: 03/14/2018] [Indexed: 06/08/2023]
Abstract
Trichloroethylene (TCE) was widely used as an industrial solvent which could cause severe liver damage. The histone chaperone SET have been identified as an important mediator of TCE-induced hepatic cytotoxicity in our previous study; however, the underlying regulatory mechanisms remain poorly understood. In this study, we found a total of 136 histone acetylation sites involved in TCE-induced hepatic cytotoxicity with the technique of Triton-acid-urea polyacrylamide gel electrophoresis (TAU-PAGE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Importantly, 17 histone acetylation sites were revealed to be mediated by SET in TCE-induced cytotoxicity. The acetylation of histone H2AK9 (H2AK9ac) was further validated by Western-blot analysis. The data showed that TCE treatment increased the acetylation of H2AK9 in hepatic L-02 cell and decreased the one in SET-knockdown L-02 cells. Besides, levels of the histone deacetylases (HDACs, including HDAC1, HDAC2, and HDAC3) was also analyzed. Interestingly, the level of HDAC1 was aberrantly suppressed in TCE-treated L-02 cells while enhanced in SET-knockdown L-02 cells. To further explore the potential role of HDAC1 in SET-mediated hepatic cytotoxicity of TCE, we employed RNA interference (RNAi) to knockdown HDAC1 in both wide type L-02 and SET-knockdown cells. The results showed that the siRNA inhibition of HDAC1 increased the acetylation of H2AK9. Taken together, our data suggested that SET promoted the acetylation of H2AK9 via suppressing the level of HDAC1, which was involved in SET-mediated hepatic cytotoxicity of TCE.
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Affiliation(s)
- Weixue Lu
- School of Chemistry, Xiangtan University, Yuhu District, Xiangtan, 411105, Hunan, China; Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, No 8 Longyuan Road, Nanshan District, Shenzhen, 518055, Guangdong, China
| | - Zhihong Chen
- Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, No 8 Longyuan Road, Nanshan District, Shenzhen, 518055, Guangdong, China; School of Public Health, Southern Medical University, Tonghe District, Guangzhou, 510515, China
| | - Xiaohu Ren
- Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, No 8 Longyuan Road, Nanshan District, Shenzhen, 518055, Guangdong, China
| | - Wei Liu
- Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, No 8 Longyuan Road, Nanshan District, Shenzhen, 518055, Guangdong, China
| | - Rongxia Deng
- Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, No 8 Longyuan Road, Nanshan District, Shenzhen, 518055, Guangdong, China
| | - Jianhui Yuan
- Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, No 8 Longyuan Road, Nanshan District, Shenzhen, 518055, Guangdong, China
| | - Xinfeng Huang
- Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, No 8 Longyuan Road, Nanshan District, Shenzhen, 518055, Guangdong, China
| | - Weiguo Zhu
- School of Chemistry, Xiangtan University, Yuhu District, Xiangtan, 411105, Hunan, China; School of Materials Science and Engineering, Jiangsu Collaboration Innovation Center of Photovoltaic Science and Engineering, Changzhou University, Wujin District, Changzhou 213164, China.
| | - Jianjun Liu
- Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, No 8 Longyuan Road, Nanshan District, Shenzhen, 518055, Guangdong, China.
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Ordaz JD, Damayanti NP, Irudayaraj JMK. Toxicological effects of trichloroethylene exposure on immune disorders. Immunopharmacol Immunotoxicol 2017; 39:305-317. [PMID: 28828896 DOI: 10.1080/08923973.2017.1364262] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Trichloroethylene (TCE) is one of the most common ground water contaminants in USA. Even though recent regulation mandates restricted utilization of TCE, its use is not completely prohibited, especially in industrial and manufacturing processes. The risk of TCE on human health is an ongoing field of study and its implications on certain diseases such as cancer has been recognized and well-documented. However, the link between TCE and immune disorders is still an under-studied area. Studies on the risk of TCE on the immune system is usually focused on certain immune class disorders, but consensus on the impact of TCE on the immune system has not been established. This review presents representative work that investigates the effect of TCE on immune disorders and highlights future opportunities. We attempt to provide a broader perspective of the risks of TCE on the immune system and human health.
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Affiliation(s)
- Josue D Ordaz
- a Department of Agricultural & Biological Engineering , Bindley Bioscience Center, Purdue University , West Lafayette , IN , USA.,b Indiana University School of Medicine , Indianapolis , IN , USA
| | - Nur P Damayanti
- a Department of Agricultural & Biological Engineering , Bindley Bioscience Center, Purdue University , West Lafayette , IN , USA.,b Indiana University School of Medicine , Indianapolis , IN , USA
| | - Joseph M K Irudayaraj
- a Department of Agricultural & Biological Engineering , Bindley Bioscience Center, Purdue University , West Lafayette , IN , USA
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Gilbert KM, Blossom SJ, Reisfeld B, Erickson SW, Vyas K, Maher M, Broadfoot B, West K, Bai S, Cooney CA, Bhattacharyya S. Trichloroethylene-induced alterations in DNA methylation were enriched in polycomb protein binding sites in effector/memory CD4 + T cells. ENVIRONMENTAL EPIGENETICS 2017; 3:dvx013. [PMID: 29129997 PMCID: PMC5676456 DOI: 10.1093/eep/dvx013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 06/30/2017] [Accepted: 07/03/2017] [Indexed: 06/07/2023]
Abstract
Exposure to industrial solvent and water pollutant trichloroethylene (TCE) can promote autoimmunity, and expand effector/memory (CD62L) CD4+ T cells. In order to better understand etiology reduced representation bisulfite sequencing was used to study how a 40-week exposure to TCE in drinking water altered methylation of ∼337 770 CpG sites across the entire genome of effector/memory CD4+ T cells from MRL+/+ mice. Regardless of TCE exposure, 62% of CpG sites in autosomal chromosomes were hypomethylated (0-15% methylation), and 25% were hypermethylated (85-100% methylation). In contrast, only 6% of the CpGs on the X chromosome were hypomethylated, and 51% had mid-range methylation levels. In terms of TCE impact, TCE altered (≥ 10%) the methylation of 233 CpG sites in effector/memory CD4+ T cells. Approximately 31.7% of these differentially methylated sites occurred in regions known to bind one or more Polycomb group (PcG) proteins, namely Ezh2, Suz12, Mtf2 or Jarid2. In comparison, only 23.3% of CpG sites not differentially methylated by TCE were found in PcG protein binding regions. Transcriptomics revealed that TCE altered the expression of ∼560 genes in the same effector/memory CD4+ T cells. At least 80% of the immune genes altered by TCE had binding sites for PcG proteins flanking their transcription start site, or were regulated by other transcription factors that were in turn ordered by PcG proteins at their own transcription start site. Thus, PcG proteins, and the differential methylation of their binding sites, may represent a new mechanism by which TCE could alter the function of effector/memory CD4+ T cells.
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Affiliation(s)
- Kathleen M. Gilbert
- Arkansas Children’s Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA
| | - Sarah J. Blossom
- Arkansas Children’s Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA
| | - Brad Reisfeld
- Colorado State University, Fort Collins, CO 80523, USA
| | - Stephen W. Erickson
- Arkansas Children’s Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA
| | - Kanan Vyas
- Arkansas Children’s Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA
| | - Mary Maher
- Arkansas Children’s Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA
| | - Brannon Broadfoot
- Arkansas Children’s Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA
| | - Kirk West
- Arkansas Children’s Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA
| | - Shasha Bai
- Arkansas Children’s Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA
| | - Craig A. Cooney
- Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, USA
| | - Sudeepa Bhattacharyya
- Arkansas Children’s Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA
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Gilbert KM, Bai S, Barnette D, Blossom SJ. Exposure Cessation During Adulthood Did Not Prevent Immunotoxicity Caused by Developmental Exposure to Low-Level Trichloroethylene in Drinking Water. Toxicol Sci 2017; 157:429-437. [PMID: 28369519 PMCID: PMC6075179 DOI: 10.1093/toxsci/kfx061] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Exposure to the water pollutant trichloroethylene (TCE) can promote autoimmunity in both humans and rodents. Using a mouse model we have shown that chronic adult exposure to TCE at 500 μg/ml in drinking water generates autoimmune hepatitis in female MRL+/+ mice. There is increasing evidence that developmental exposure to certain chemicals can be more toxic than adult exposure. This study was designed to test whether exposure to a much lower level of TCE (0.05 μg/ml) during gestation, lactation, and early life generated autoimmunity similar to that found following adult exposure to higher concentrations of TCE. When female MRL+/+ mice were examined at postnatal day (PND) 259 we found that developmental/early life exposure [gestational day 0 to PND 154] to TCE at a concentration 10 000 fold lower than that shown to be effective for adult exposure triggered autoimmune hepatitis. This effect was observed despite exposure cessation at PND 154. In concordance with the liver pathology, female MRL+/+ exposed during development and early life to TCE (0.05 or 500 μg/ml) generated a range of antiliver antibodies detected by Western blotting. Expression of proinflammatory cytokines by CD4+ T cells was also similarly observed at PND 259 in the TCE-exposed mice regardless of concentration. Thus, exposure to TCE at approximately environmental levels from gestational day 0 to PND 154 generated tissue pathology and CD4+ T cell alterations that required higher concentrations if exposure was limited to adulthood. TCE exposure cessation at PND 154 did not prevent the immunotoxicity.
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Affiliation(s)
- Kathleen M. Gilbert
- *Department of Microbiology and Immunology; Department of Biochemistry and Molecular Biology; and Department of Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children’s Research Institute, Little Rock, Arkansas 72202
| | - Shasha Bai
- *Department of Microbiology and Immunology; Department of Biochemistry and Molecular Biology; and Department of Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children’s Research Institute, Little Rock, Arkansas 72202
| | - Dustyn Barnette
- *Department of Microbiology and Immunology; Department of Biochemistry and Molecular Biology; and Department of Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children’s Research Institute, Little Rock, Arkansas 72202
| | - Sarah J. Blossom
- *Department of Microbiology and Immunology; Department of Biochemistry and Molecular Biology; and Department of Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children’s Research Institute, Little Rock, Arkansas 72202
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Kochmanski J, Montrose L, Goodrich JM, Dolinoy DC. Environmental Deflection: The Impact of Toxicant Exposures on the Aging Epigenome. Toxicol Sci 2017; 156:325-335. [PMID: 28087834 PMCID: PMC6256948 DOI: 10.1093/toxsci/kfx005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Epigenetic drift and age-related methylation have both been used in the literature to describe changes in DNA methylation that occurs with aging. However, ambiguity remains regarding the exact definition of both of these terms, and neither of these fields of study explicitly considers the impact of environmental factors on the aging epigenome. Recent twin studies have demonstrated longitudinal, pair-specific discordance in DNA methylation patterns, suggesting an effect of the environment on age-related methylation and/or epigenetic drift. Supporting this idea, other new reports have shown clear environment- and toxicant-mediated shifts away from the baseline rates of age-related methylation and epigenetic drift within an organism, a process we now term "environmental deflection." By defining and delineating environmental deflection, this contemporary review aims to highlight the effects of specific toxicological factors on the rate of DNA methylation changes that occur over the life course. In an effort to inform future epigenetics-based toxicology studies, a field of research now classified as toxicoepigenetics, we provide clear definitions and examples of "epigenetic drift" and "age-related methylation," summarize the recent evidence for environmental deflection of the aging epigenome, and discuss the potential functional effects of environmental deflection.
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Affiliation(s)
| | | | | | - Dana C. Dolinoy
- Environmental Health Sciences
- Nutritional Sciences, School of Public Health, University of Michigan, Washington Heights, Ann Arbor, Michigan 48109
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Gilbert KM, Blossom SJ, Erickson SW, Broadfoot B, West K, Bai S, Li J, Cooney CA. Chronic exposure to trichloroethylene increases DNA methylation of the Ifng promoter in CD4 + T cells. Toxicol Lett 2016; 260:1-7. [PMID: 27553676 PMCID: PMC5065104 DOI: 10.1016/j.toxlet.2016.08.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 07/12/2016] [Accepted: 08/19/2016] [Indexed: 01/04/2023]
Abstract
CD4+ T cells in female MRL+/+ mice exposed to solvent and water pollutant trichloroethylene (TCE) skew toward effector/memory CD4+ T cells, and demonstrate seemingly non-monotonic alterations in IFN-γ production. In the current study we examined the mechanism for this immunotoxicity using effector/memory and naïve CD4+ T cells isolated every 6 weeks during a 40 week exposure to TCE (0.5mg/ml in drinking water). A time-dependent effect of TCE exposure on both Ifng gene expression and IFN-γ protein production was observed in effector/memory CD4+ T cells, with an increase after 22 weeks of exposure and a decrease after 40 weeks of exposure. No such effect of TCE was observed in naïve CD4+ T cells. A cumulative increase in DNA methylation in the CpG sites of the promoter of the Ifng gene was observed in effector/memory, but not naïve, CD4+ T cells over time. Also unique to the Ifng promoter was an increase in methylation variance in effector/memory compared to naïve CD4+ T cells. Taken together, the CpG sites of the Ifng promoter in effector/memory CD4+ T cells were especially sensitive to the effects of TCE exposure, which may help explain the regulatory effect of the chemical on this gene.
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Affiliation(s)
- Kathleen M Gilbert
- University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, United States.
| | - Sarah J Blossom
- University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, United States.
| | - Stephen W Erickson
- University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, United States.
| | - Brannon Broadfoot
- University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, United States.
| | - Kirk West
- University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, United States.
| | - Shasha Bai
- University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, United States.
| | - Jingyun Li
- University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, United States.
| | - Craig A Cooney
- Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, United States.
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Gilbert KM, Blossom SJ, Erickson SW, Reisfeld B, Zurlinden TJ, Broadfoot B, West K, Bai S, Cooney CA. Chronic exposure to water pollutant trichloroethylene increased epigenetic drift in CD4(+) T cells. Epigenomics 2016; 8:633-49. [PMID: 27092578 DOI: 10.2217/epi-2015-0018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
AIM Autoimmune disease and CD4(+) T-cell alterations are induced in mice exposed to the water pollutant trichloroethylene (TCE). We examined here whether TCE altered gene-specific DNA methylation in CD4(+) T cells as a possible mechanism of immunotoxicity. MATERIALS & METHODS Naive and effector/memory CD4(+) T cells from mice exposed to TCE (0.5 mg/ml in drinking water) for 40 weeks were examined by bisulfite next-generation DNA sequencing. RESULTS A probabilistic model calculated from multiple genes showed that TCE decreased methylation control in CD4(+) T cells. Data from individual genes fitted to a quadratic regression model showed that TCE increased gene-specific methylation variance in both CD4 subsets. CONCLUSION TCE increased epigenetic drift of specific CpG sites in CD4(+) T cells.
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Affiliation(s)
- Kathleen M Gilbert
- Departments of Microbiology & Immunology, & Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, USA
| | - Sarah J Blossom
- Departments of Microbiology & Immunology, & Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, USA
| | - Stephen W Erickson
- Departments of Microbiology & Immunology, & Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, USA
| | - Brad Reisfeld
- College of Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - Todd J Zurlinden
- College of Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - Brannon Broadfoot
- Departments of Microbiology & Immunology, & Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, USA
| | - Kirk West
- Departments of Microbiology & Immunology, & Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, USA
| | - Shasha Bai
- Departments of Microbiology & Immunology, & Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR 72202, USA
| | - Craig A Cooney
- Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, USA
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Wang F, Zha WS, Zhang JX, Li SL, Wang H, Ye LP, Shen T, Wu CH, Zhu QX. Complement C3a binding to its receptor as a negative modulator of Th2 response in liver injury in trichloroethylene-sensitized mice. Toxicol Lett 2014; 229:229-39. [DOI: 10.1016/j.toxlet.2014.06.841] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 06/24/2014] [Accepted: 06/25/2014] [Indexed: 11/27/2022]
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Analysis of trichloroethylene-induced global DNA hypomethylation in hepatic L-02 cells by liquid chromatography-electrospray ionization tandem mass spectrometry. Biochem Biophys Res Commun 2014; 446:590-5. [PMID: 24632203 DOI: 10.1016/j.bbrc.2014.03.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 03/04/2014] [Indexed: 12/31/2022]
Abstract
Trichloroethylene (TCE), a major occupational and environmental pollutant, has been recently associated with aberrant epigenetic changes in experimental animals and cultured cells. TCE is known to cause severe hepatotoxicity; however, the association between epigenetic alterations and TCE-induced hepatotoxicity are not yet well explored. DNA methylation, catalyzed by enzymes known as DNA methyltransferases (DNMT), is a major epigenetic modification that plays a critical role in regulating many cellular processes. In this study, we analyzed the TCE-induced effect on global DNA methylation and DNMT enzymatic activity in human hepatic L-02 cells. A sensitive and quantitative method combined with liquid chromatography and electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was validated and utilized for assessing the altered DNA methylation in TCE-induced L-02 cells. Quantification was accomplished in multiple reaction monitoring (MRM) mode by monitoring a transition pair of m/z 242.1 (molecular ion)/126.3 (fragment ion) for 5-mdC and m/z 268.1/152.3 for dG. The correlation coefficient of calibration curves between 5-mdC and dG was higher than 0.9990. The intra-day and inter-day relative standard derivation values (RSD) were on the range of 0.53-7.09% and 0.40-2.83%, respectively. We found that TCE exposure was able to significantly decrease the DNA methylation and inhibit DNMT activity in L-02 cells. Our results not only reveal the association between TCE exposure and epigenetic alterations, but also provide an alternative mass spectrometry-based method for rapid and accurate assessment of chemical-induced altered DNA methylation in mammal cells.
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Blossom SJ, Cooney CA, Melnyk SB, Rau JL, Swearingen CJ, Wessinger WD. Metabolic changes and DNA hypomethylation in cerebellum are associated with behavioral alterations in mice exposed to trichloroethylene postnatally. Toxicol Appl Pharmacol 2013; 269:263-9. [PMID: 23566951 DOI: 10.1016/j.taap.2013.03.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/16/2013] [Accepted: 03/18/2013] [Indexed: 02/07/2023]
Abstract
Previous studies demonstrated that low-level postnatal and early life exposure to the environmental contaminant, trichloroethylene (TCE), in the drinking water of MRL+/+ mice altered glutathione redox homeostasis and increased biomarkers of oxidative stress indicating a more oxidized state. Plasma metabolites along the interrelated transmethylation pathway were also altered indicating impaired methylation capacity. Here we extend these findings to further characterize the impact of TCE exposure in mice exposed to water only or two doses of TCE in the drinking water (0, 2, and 28mg/kg/day) postnatally from birth until 6weeks of age on redox homeostasis and biomarkers of oxidative stress in the cerebellum. In addition, pathway intermediates involved in methyl metabolism and global DNA methylation patterns were examined in cerebellar tissue. Because the cerebellum is functionally important for coordinating motor activity, including exploratory and social approach behaviors, these parameters were evaluated in the present study. Mice exposed to 28mg/kg/day TCE exhibited increased locomotor activity over time as compared with control mice. In the novel object exploration test, these mice were more likely to enter the zone with the novel object as compared to control mice. Similar results were obtained in a second test when an unfamiliar mouse was introduced into the testing arena. The results show for the first time that postnatal exposure to TCE causes key metabolic changes in the cerebellum that may contribute to global DNA methylation deficits and behavioral alterations in TCE-exposed mice.
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Affiliation(s)
- Sarah J Blossom
- Department of Pediatrics, University of Arkansas for Medical Sciences, College of Medicine, Arkansas Children's Hospital Research Institute, 13 Children's Way, Little Rock, AR 72202, USA.
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Blossom SJ, Melnyk S, Cooney CA, Gilbert KM, James SJ. Postnatal exposure to trichloroethylene alters glutathione redox homeostasis, methylation potential, and neurotrophin expression in the mouse hippocampus. Neurotoxicology 2012; 33:1518-1527. [PMID: 22421312 DOI: 10.1016/j.neuro.2012.02.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 02/27/2012] [Accepted: 02/27/2012] [Indexed: 12/23/2022]
Abstract
Previous studies have shown that continuous exposure throughout gestation until the juvenile period to environmentally relevant doses of trichloroethylene (TCE) in the drinking water of MRL+/+ mice promoted adverse behavior associated with glutathione depletion in the cerebellum indicating increased sensitivity to oxidative stress. The purpose of this study was to extend our findings and further characterize the impact of TCE exposure on redox homeostasis and biomarkers of oxidative stress in the hippocampus, a brain region prone to oxidative stress. Instead of a continuous exposure, the mice were exposed to water only or two environmentally relevant doses of TCE in the drinking water postnatally from birth until 6 weeks of age. Biomarkers of plasma metabolites in the transsulfuration pathway and the transmethylation pathway of the methionine cycle were also examined. Gene expression of neurotrophins was examined to investigate a possible relationship between oxidative stress, redox imbalance and neurotrophic factor expression with TCE exposure. Our results show that hippocampi isolated from male mice exposed to TCE showed altered glutathione redox homeostasis indicating a more oxidized state. Also observed was a significant, dose dependent increase in glutathione precursors. Plasma from the TCE treated mice showed alterations in metabolites in the transsulfuration and transmethylation pathways indicating redox imbalance and altered methylation capacity. 3-Nitrotyrosine, a biomarker of protein oxidative stress, was also significantly higher in plasma and hippocampus of TCE-exposed mice compared to controls. In contrast, expression of key neurotrophic factors in the hippocampus (BDNF, NGF, and NT-3) was significantly reduced compared to controls. Our results demonstrate that low-level postnatal and early life TCE exposure modulates neurotrophin gene expression in the mouse hippocampus and may provide a mechanism for TCE-mediated neurotoxicity.
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Affiliation(s)
- Sarah J Blossom
- Department of Pediatrics, University of Arkansas for Medical Sciences, College of Medicine, Arkansas Children's Hospital Research Institute, 13 Children's Way, Little Rock, AR 72202, United States.
| | - Stepan Melnyk
- Department of Pediatrics, University of Arkansas for Medical Sciences, College of Medicine, Arkansas Children's Hospital Research Institute, 13 Children's Way, Little Rock, AR 72202, United States
| | - Craig A Cooney
- Department of Research and Development, Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, United States
| | - Kathleen M Gilbert
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, College of Medicine, Arkansas Children's Hospital Research Institute, 13 Children's Way, Little Rock, AR 72202, United States
| | - S Jill James
- Department of Pediatrics, University of Arkansas for Medical Sciences, College of Medicine, Arkansas Children's Hospital Research Institute, 13 Children's Way, Little Rock, AR 72202, United States
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