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Rodrigues de Souza I, Savio de Araujo-Souza P, Morais Leme D. Genetic variants affecting chemical mediated skin immunotoxicity. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2022; 25:43-95. [PMID: 34979876 DOI: 10.1080/10937404.2021.2013372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The skin is an immune-competent organ and this function may be impaired by exposure to chemicals, which may ultimately result in immune-mediated dermal disorders. Interindividual variability to chemical-induced skin immune reactions is associated with intrinsic individual characteristics and their genomes. In the last 30-40 years, several genes influencing susceptibility to skin immune reactions were identified. The aim of this review is to provide information regarding common genetic variations affecting skin immunotoxicity. The polymorphisms selected for this review are related to xenobiotic-metabolizing enzymes (CYPA1 and CYPB1 genes), antioxidant defense (GSTM1, GSTT1, and GSTP1 genes), aryl hydrocarbon receptor signaling pathway (AHR and ARNT genes), skin barrier function transepidermal water loss (FLG, CASP14, and SPINK5 genes), inflammation (TNF, IL10, IL6, IL18, IL31, and TSLP genes), major histocompatibility complex (MHC) and neuroendocrine system peptides (CALCA, TRPV1, ACE genes). These genes present variants associated with skin immune responses and diseases, as well as variants associated with protecting skin immune homeostasis following chemical exposure. The molecular and association studies focusing on these genetic variants may elucidate their functional consequences and contribution in the susceptibility to skin immunotoxicity. Providing information on how genetic variations affect the skin immune system may reduce uncertainties in estimating chemical hazards/risks for human health in the future.
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Affiliation(s)
| | | | - Daniela Morais Leme
- Graduate Program in Genetics, Department of Genetics, Federal University of Paraná (UFPR), Curitiba, Brazil
- National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM), Institute of Chemistry, Araraquara, Brazil
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2
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Lei Z, Yu S, Ding Y, Liang J, Halifu Y, Xiang F, Zhang D, Wang H, Hu W, Li T, Wang Y, Zou X, Zhang K, Kang X. Identification of key genes and pathways involved in vitiligo development based on integrated analysis. Medicine (Baltimore) 2020; 99:e21297. [PMID: 32756109 PMCID: PMC7402735 DOI: 10.1097/md.0000000000021297] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Vitiligo is a chronic skin condition lack of melanocytes. However, researches on the aetiology and pathogenesis of vitiligo are still under debate. This study aimed to explore the key genes and pathways associated with occurrence and development of vitiligo.Weighted gene coexpression network analysis (WGCNA) was applied to reanalyze the gene expression dataset GSE65127 systematically. Functional enrichments of these modules were carried out at gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), gene set variation analysis (GSVA), and gene set enrichment analysis (GSEA). Then, a map of regulatory network was delineated according to pivot analysis and drug prediction. In addition, hub genes and crucial pathways were validated by an independent dataset GSE75819. The expressions of hub genes in modules were also tested by quantitative real-time polymerase chain reaction (qRT-PCR).Eight coexpressed modules were identified by WGCNA based on 5794 differentially expressed genes of vitiligo. Three modules were found to be significantly correlated with Lesional, Peri-Lesional, and Non-Lesional, respectively. The persistent maladjusted genes included 269 upregulated genes and 82 downregulated genes. The enrichments showed module genes were implicated in immune response, p53 signaling pathway, etc. According to GSEA and GSVA, dysregulated pathways were activated incessantly from Non-Lesional to Peri-Lesional and then to Lesional, 4 of which were verified by an independent dataset GSE75819. Finally, 42 transcription factors and 228 drugs were spotted. Focusing on the persistent maladjusted genes, a map of regulatory network was delineated. Hub genes (CACTIN, DCTN1, GPR143, HADH, MRPL47, NKTR, NUF2) and transcription factors (ITGAV, SYK, PDPK1) were validated by an independent dataset GSE75819. In addition, hub genes (CACTIN, DCTN1, GPR143, MRPL47, NKTR) were also confirmed by qRT-PCR.The present study, at least, might provide an integrated and in-depth insight for exploring the underlying mechanism of vitiligo and predicting potential diagnostic biomarkers and therapeutic targets.
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Affiliation(s)
| | - Shirong Yu
- Department of Dermatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
| | - Yuan Ding
- Department of Dermatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
| | - Junqin Liang
- Department of Dermatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
| | - Yilinuer Halifu
- Department of Dermatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
| | - Fang Xiang
- Department of Dermatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
| | - Dezhi Zhang
- Department of Dermatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
| | - Hongjuan Wang
- Department of Dermatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
| | - Wen Hu
- Department of Dermatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
| | - Tingting Li
- Department of Dermatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
| | - Yunying Wang
- Department of Dermatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
| | - Xuelian Zou
- Department of Dermatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
| | - Kunjie Zhang
- Department of Dermatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
| | - Xiaojing Kang
- Department of Dermatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
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Yamashita N, Saito N, Zhao S, Terai K, Hiruta N, Park Y, Bujo H, Nemoto K, Kanno Y. Heregulin-induced cell migration is promoted by aryl hydrocarbon receptor in HER2-overexpressing breast cancer cells. Exp Cell Res 2018; 366:34-40. [PMID: 29501698 DOI: 10.1016/j.yexcr.2018.02.033] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 02/16/2018] [Accepted: 02/26/2018] [Indexed: 12/19/2022]
Abstract
HER2 overexpression accounts for approximately 15-20% of all breast cancers. We have shown that HER2 overexpression leads to elevated expression of the aryl hydrocarbon receptor (AhR) in breast cancer cells. In this study, firstly, we showed that AhR expression was up-regulated by treatment with the HER3 ligand heregulin (HRG) in HER2-overexpressing breast cancer cell lines. Induction of AhR was mediated by transcriptional activation of the region of AhR promoter corresponding to - 190 to - 100 bp. In addition, HRG treatment elicited nuclear translocation of AhR. To investigate the role of AhR in HRG-HER2/HER3 signaling in HER2-overexpressing cells, we established AhR knockout (KO) HER2-overexpressing cells to perform wound-healing assays. HRG-induced cell migration was markedly attenuated by AhR KO. HRG-induced cell migration was associated with increased expression of the inflammatory cytokines interleukin (IL)-6 and IL-8 in wild type cells, but not in AhR KO cells. These results elucidate that AhR is an important factor for the malignancy in HER2 overexpressing breast cancers.
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Affiliation(s)
- Naoya Yamashita
- Department of Molecular Toxicology, Faculty of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan
| | - Nao Saito
- Department of Molecular Toxicology, Faculty of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan
| | - Shuai Zhao
- Department of Molecular Toxicology, Faculty of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan
| | - Kensuke Terai
- Department of Clinical-Laboratory and Experimental-Research Medicine, Toho University Sakura Medical Center, Shimoshizu 564-1, Sakura, Chiba 285-8741, Japan; Department of Surgical Pathology, Toho University Sakura Medical Center, Shimoshizu 564-1, Sakura, Chiba 285-8741, Japan
| | - Nobuyuki Hiruta
- Department of Clinical-Laboratory and Experimental-Research Medicine, Toho University Sakura Medical Center, Shimoshizu 564-1, Sakura, Chiba 285-8741, Japan; Department of Surgical Pathology, Toho University Sakura Medical Center, Shimoshizu 564-1, Sakura, Chiba 285-8741, Japan
| | - Youngjin Park
- Department of Surgery, Toho University Sakura Medical Center, Shimoshizu 564-1, Sakura, Chiba 285-8741, Japan; Department of Breast and Endocrine Surgery, Tohoku Medical and Pharmaceutical University, Fukumuro 1-15-1, Miyagino-ku, Sendai, Miyagi prefecture, 983-8536, Japan
| | - Hideaki Bujo
- Department of Clinical-Laboratory and Experimental-Research Medicine, Toho University Sakura Medical Center, Shimoshizu 564-1, Sakura, Chiba 285-8741, Japan
| | - Kiyomitsu Nemoto
- Department of Molecular Toxicology, Faculty of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan
| | - Yuichiro Kanno
- Department of Breast and Endocrine Surgery, Tohoku Medical and Pharmaceutical University, Fukumuro 1-15-1, Miyagino-ku, Sendai, Miyagi prefecture, 983-8536, Japan.
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Fracchiolla NS, Annaloro C, Guidotti F, Fattizzo B, Cortelezzi A. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) role in hematopoiesis and in hematologic diseases: A critical review. Toxicology 2016; 374:60-68. [PMID: 27765685 DOI: 10.1016/j.tox.2016.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/03/2016] [Accepted: 10/13/2016] [Indexed: 12/12/2022]
Abstract
Dioxin exposure and its effect on hematopoiesis and cancer have been largely investigated in both human and non-human settings. Here we systematically reviewed literature to address the question of what we know about TCDD biology and exposure. Most effects are due to TCDD interaction with a receptor of xenobiotics called AHR, which is ubiquitously represented and also works on hematopoietic myeloid and lymphoid stem cells, inducing proliferation and stem cell release from bone marrow to peripheral circulation. Epidemiologic studies on TCDD exposure demonstrated an association with onco-hematologic diseases, particularly with non Hodgkin lymphomas and multiple myeloma, and non hematologic cancers, such as sarcomas, although these relationships are affected by multiple confounding factors.
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Affiliation(s)
- Nicola Stefano Fracchiolla
- UO Onco-Hematology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via F. Sforza 35, 20100, Milano, Italy.
| | - Claudio Annaloro
- UO Onco-Hematology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via F. Sforza 35, 20100, Milano, Italy
| | - Francesca Guidotti
- UO Onco-Hematology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via F. Sforza 35, 20100, Milano, Italy
| | - Bruno Fattizzo
- UO Onco-Hematology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via F. Sforza 35, 20100, Milano, Italy
| | - Agostino Cortelezzi
- UO Onco-Hematology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via F. Sforza 35, 20100, Milano, Italy; UO Onco-Hematology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via F Sforza 35, 20100, Milano, Italy
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5
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Wang X, Li K, Liu L, Shi Q, Song P, Jian Z, Guo S, Wang G, Li C, Gao T. AHR promoter variant modulates its transcription and downstream effectors by allele-specific AHR-SP1 interaction functioning as a genetic marker for vitiligo. Sci Rep 2015; 5:13542. [PMID: 26370050 PMCID: PMC4570213 DOI: 10.1038/srep13542] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/30/2015] [Indexed: 12/28/2022] Open
Abstract
Vitiligo is an acquired depigmentation disorder largely caused by defective melanocyte- or autoimmunity-induced melanocyte destruction. The aryl hydrocarbon receptor (AHR) is essential for melanocyte homeostasis and immune process, and abnormal AHR was observed in vitiligo. We previously identified the T allele of AHR -129C > T variant as a protective factor against vitiligo. However, biological characterization underlying such effects is not fully certain, further validation by mechanistic research is warranted and was conducted in the present study. We showed that -129T allele promoted AHR transcriptional activity through facilitating its interaction with SP1 transcription factor (SP1) compared with -129C allele. We subsequently found reduced peripheral AHR and SP1 transcript expressions in vitiligo and a negative correlation of AHR level with disease duration. We also investigated AHR-related cytokines and observed increased serum TNF-α concentration and diminished serum levels of IL-10 and TGF-β1 in vitiligo. Further genetic analysis showed that -129T carriers possessed higher levels of AHR and IL-10 than -129C carriers. Therefore, our study indicates that the modulation of AHR transcription by a promoter variant has a profound influence on vitiligo, not only advancing our understanding on AHR function but also providing novel insight into the pathogenesis of degenerative or autoimmune diseases including vitiligo.
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Affiliation(s)
- Xiaowen Wang
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Kai Li
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Ling Liu
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Qiong Shi
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Pu Song
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Zhe Jian
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Sen Guo
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Gang Wang
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Chunying Li
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Tianwen Gao
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, China
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6
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Liu C, Xing X, Chen L, Li D, Bai Q, Wang Q, Yu H, Zeng X, Wei Q, Gao C, Zhang Z, Zhang J, He Z, Ma L, Li J, Duan H, Zheng Y, Xiao Y, Chen W. Specific histone modifications regulate the expression of AhR in 16HBE cells exposed to benzo(a)pyrene. Toxicol Res (Camb) 2015. [DOI: 10.1039/c4tx00088a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Our study identified specific histone modifications that were involved in down regulation of the transcription of AhR, conferring cells resistance to cellular damage.
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7
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Spink BC, Bloom MS, Wu S, Sell S, Schneider E, Ding X, Spink DC. Analysis of the AHR gene proximal promoter GGGGC-repeat polymorphism in lung, breast, and colon cancer. Toxicol Appl Pharmacol 2014; 282:30-41. [PMID: 25447411 DOI: 10.1016/j.taap.2014.10.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 09/26/2014] [Accepted: 10/27/2014] [Indexed: 02/05/2023]
Abstract
The aryl hydrocarbon receptor (AhR) regulates expression of numerous genes, including those of the CYP1 gene family. With the goal of determining factors that control AHR gene expression, our studies are focused on the role of the short tandem repeat polymorphism, (GGGGC)n, located in the proximal promoter of the human AHR gene. When luciferase constructs containing varying GGGGC repeats were transfected into cancer cell lines derived from the lung, colon, and breast, the number of GGGGC repeats affected AHR promoter activity. The number of GGGGC repeats was determined in DNA from 327 humans and from 38 samples representing 5 species of non-human primates. In chimpanzees and 3 species of macaques, only (GGGGC)2 alleles were observed; however, in western gorilla, (GGGGC)n alleles with n=2, 4, 5, 6, 7, and 8 were identified. In all human populations examined, the frequency of (GGGGC)n was n=4>5≫2, 6. When frequencies of the (GGGGC)n alleles in DNA from patients with lung, colon, or breast cancer were evaluated, the occurrence of (GGGGC)2 was found to be 8-fold more frequent among lung cancer patients in comparison with its incidence in the general population, as represented by New York State neonates. Analysis of matched tumor and non-tumor DNA samples from the same individuals provided no evidence of microsatellite instability. These studies indicate that the (GGGGC)n short tandem repeats are inherited, and that the (GGGGC)2 allele in the AHR proximal promoter region should be further investigated with regard to its potential association with lung cancer susceptibility.
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Affiliation(s)
- Barbara C Spink
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, United States
| | - Michael S Bloom
- Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY 12201, United States
| | - Susan Wu
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, United States
| | - Stewart Sell
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, United States; Department of Biomedical Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY 12201, United States
| | - Erasmus Schneider
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, United States; Department of Biomedical Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY 12201, United States
| | - Xinxin Ding
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, United States; Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY 12201, United States; Department of Biomedical Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY 12201, United States
| | - David C Spink
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, United States; Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY 12201, United States.
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8
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Estrogen receptor α and aryl hydrocarbon receptor cross-talk in a transfected hepatoma cell line (HepG2) exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin. Toxicol Rep 2014; 1:1029-1036. [PMID: 28962316 PMCID: PMC5598243 DOI: 10.1016/j.toxrep.2014.09.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/11/2014] [Accepted: 09/30/2014] [Indexed: 01/07/2023] Open
Abstract
The prototype dioxin congener 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is known to exert anti-estrogenic effects via activation of the aryl hydrocarbon receptor (AhR) by interfering with the regulation of oestrogen homeostasis and the estrogen receptor α (ERα) signalling pathway. The AhR/ER cross-talk is considered to play a crucial role in TCDD- and E2-dependent mechanisms of carcinogenesis, though the concerted mechanism of action in the liver is not yet elucidated. The present study investigated TCDD's impact on the transcriptional cross-talk between AhR and ERα and its modulation by 17β-estradiol (E2) in the human hepatoma cell line HepG2, which is AhR-responsive but ERα-negative. Transient transfection assays with co-transfection of hERα and supplementation of receptor antagonists showed anti-estrogenic action of TCDD via down-regulation of E2-induced ERα signaling. In contrast, enhancement of AhR signaling dependent on ERα was observed providing evidence for increased cytochrome P450 (CYP) induction to promote E2 metabolism. However, relative mRNA levels of major E2-metabolizing CYP1A1 and 1B1 and the main E2-detoxifying catechol-O-methyltransferase were not affected by the co-treatments. This study provides new evidence of a TCDD-activated AhR-mediated molecular AhR/ERα cross-talk mechanism at transcriptional level via indirect inhibition of ERα and enhanced transcriptional activity of AhR in HepG2 cells.
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Key Words
- 17β-estradiol
- AhR
- AhR, aryl hydrocarbon receptor
- COMT, catechol-O-methyltransferase
- CPRG, chlorophenol red β-d-galactopyranoside
- CYP, cytochrome P450
- Ct, cycle threshold
- DMSO, dimethyl sulfoxide
- Dioxin
- E, strogen receptor
- E2, 17β-estradiol
- ERE, estrogen response element
- Estrogen receptor
- Gene reporter assay
- Human hepatoma cell line HepG2
- TCDD
- TCDD, 2,3,7,8-tetrachlorodibenzo-p-dioxin
- XRE, xenobiotic response element
- α-NF, α-naphthoflavone
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Do MT, Kim HG, Tran TTP, Khanal T, Choi JH, Chung YC, Jeong TC, Jeong HG. Metformin suppresses CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating aryl hydrocarbon receptor expression. Toxicol Appl Pharmacol 2014; 280:138-48. [DOI: 10.1016/j.taap.2014.07.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 06/26/2014] [Accepted: 07/29/2014] [Indexed: 11/28/2022]
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10
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Hecht E, Zago M, Sarill M, Rico de Souza A, Gomez A, Matthews J, Hamid Q, Eidelman DH, Baglole CJ. Aryl hydrocarbon receptor-dependent regulation of miR-196a expression controls lung fibroblast apoptosis but not proliferation. Toxicol Appl Pharmacol 2014; 280:511-25. [PMID: 25178717 DOI: 10.1016/j.taap.2014.08.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 08/20/2014] [Accepted: 08/22/2014] [Indexed: 12/29/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor implicated in the regulation of apoptosis and proliferation. Although activation of the AhR by xenobiotics such as dioxin inhibits the cell cycle and control apoptosis, paradoxically, AhR expression also promotes cell proliferation and survival independent of exogenous ligands. The microRNA (miRNA) miR-196a has also emerged as a regulator of proliferation and apoptosis but a relationship between the AhR and miR-196a is not known. Therefore, we hypothesized that AhR-dependent regulation of endogenous miR-196a expression would promote cell survival and proliferation. Utilizing lung fibroblasts from AhR deficient (AhR(-/-)) and wild-type (AhR(+/+)) mice, we show that there is ligand-independent regulation of miRNA, including low miR-196a in AhR(-/-) cells. Validation by qRT-PCR revealed a significant decrease in basal expression of miR-196a in AhR(-/-) compared to AhR(+/+) cells. Exposure to AhR agonists benzo[a]pyrene (B[a]P) and FICZ as well as AhR antagonist CH-223191 decreased miR-196a expression in AhR(+/+) fibroblasts concomitant with decreased AhR protein levels. There was increased proliferation only in AhR(+/+) lung fibroblasts in response to serum, corresponding to a decrease in p27(KIP1) protein, a cyclin-dependent kinase inhibitor. Increasing the cellular levels of miR-196a had no effect on proliferation or expression of p27(KIP1) in AhR(-/-) fibroblasts but attenuated cigarette smoke-induced apoptosis. This study provides the first evidence that AhR expression is essential for the physiological regulation of cellular miRNA levels- including miR-196a. Future experiments designed to elucidate the functional relationship between the AhR and miR-196a may delineate additional novel ligand-independent roles for the AhR.
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Affiliation(s)
- Emelia Hecht
- Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Michela Zago
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | - Miles Sarill
- Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Angela Rico de Souza
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | - Alvin Gomez
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Jason Matthews
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Qutayba Hamid
- Department of Medicine, McGill University, Montreal, Quebec, Canada; Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | - David H Eidelman
- Department of Medicine, McGill University, Montreal, Quebec, Canada; Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | - Carolyn J Baglole
- Department of Medicine, McGill University, Montreal, Quebec, Canada; Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada.
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11
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Zago M, Sheridan JA, Nair P, Rico de Souza A, Gallouzi IE, Rousseau S, Di Marco S, Hamid Q, Eidelman DH, Baglole CJ. Aryl hydrocarbon receptor-dependent retention of nuclear HuR suppresses cigarette smoke-induced cyclooxygenase-2 expression independent of DNA-binding. PLoS One 2013; 8:e74953. [PMID: 24086407 PMCID: PMC3785509 DOI: 10.1371/journal.pone.0074953] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 08/07/2013] [Indexed: 12/02/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that responds to man-made environmental toxicants, has emerged as an endogenous regulator of cyclooxygenase-2 (Cox-2) by a mechanism that is poorly understood. In this study, we first used AhR-deficient (AhR−/−) primary pulmonary cells, together with pharmacological tools to inhibit new RNA synthesis, to show that the AhR is a prominent factor in the destabilization of Cox-2 mRNA. The destabilization of Cox-2 mRNA and subsequent suppression of cigarette smoke-induced COX-2 protein expression by the AhR was independent of its ability to bind the dioxin response element (DRE), thereby differentiating the DRE-driven toxicological AhR pathway from its anti-inflammatory abilities. We further describe that the AhR destabilizes Cox-2 mRNA by sequestering HuR within the nucleus. The role of HuR in AhR stabilization of Cox-2 mRNA was confirmed by knockdown of HuR, which resulted in rapid Cox-2 mRNA degradation. Finally, in the lungs of AhR−/− mice exposed to cigarette smoke, there was little Cox-2 mRNA despite robust COX-2 protein expression, a finding that correlates with almost exclusive cytoplasmic HuR within the lungs of AhR−/− mice. Therefore, we propose that the AhR plays an important role in suppressing the expression of inflammatory proteins, a function that extends beyond the ability of the AhR to respond to man-made toxicants. These findings open the possibility that a DRE-independent AhR pathway may be exploited therapeutically as an anti-inflammatory target.
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MESH Headings
- Animals
- Azo Compounds/pharmacology
- Cell Nucleus/drug effects
- Cell Nucleus/metabolism
- Cells, Cultured
- Cyclooxygenase 2/genetics
- Cyclooxygenase 2/metabolism
- DNA/metabolism
- ELAV Proteins/metabolism
- Fibroblasts/drug effects
- Fibroblasts/enzymology
- Fibroblasts/pathology
- Humans
- Lung/pathology
- Mice
- Models, Biological
- Prostaglandins/biosynthesis
- Protein Binding/drug effects
- Protein Structure, Tertiary
- Protein Transport/drug effects
- Pyrazoles/pharmacology
- RNA Stability/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Small Interfering/metabolism
- Receptors, Aryl Hydrocarbon/antagonists & inhibitors
- Receptors, Aryl Hydrocarbon/chemistry
- Receptors, Aryl Hydrocarbon/deficiency
- Receptors, Aryl Hydrocarbon/metabolism
- Smoking/adverse effects
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Affiliation(s)
- Michela Zago
- Department of Medicine, McGill University, Montreal, Quebec, Canada
| | | | - Parameswaran Nair
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Angela Rico de Souza
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Imed-Eddine Gallouzi
- Department of Biochemistry and the Goodman Cancer Centre, McGill University, Montreal, Quebec, Canada
| | - Simon Rousseau
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Sergio Di Marco
- Department of Biochemistry and the Goodman Cancer Centre, McGill University, Montreal, Quebec, Canada
| | - Qutayba Hamid
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - David H. Eidelman
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Carolyn J. Baglole
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- * E-mail:
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12
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Wang XW, Li K, Guo S, Qiang HN, Liu L, Song P, Wei C, Yi XL, Jian Z, Li Q, Li CY, Gao TW. The association of functional polymorphisms in the aryl hydrocarbon receptor (AHR) gene with the risk of vitiligo in Han Chinese populations. Br J Dermatol 2012; 166:1081-7. [PMID: 22211302 DOI: 10.1111/j.1365-2133.2011.10798.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Vitiligo is an acquired depigmentation disorder resulting from selective destruction of melanocytes. The aryl hydrocarbon receptor (AHR) is vital to the regulation of melanogenesis and melanocyte proliferation and differentiation through modulating the expressions of melanogenesis-related genes. AHR mutations may negatively affect AHR proteins and its target genes. Therefore, we hypothesized that AHR polymorphisms might be involved in vitiligo by impacting the transcriptional activities of related genes as mentioned above. OBJECTIVES To evaluate the potential association between AHR polymorphisms and vitiligo susceptibility. METHODS We performed a hospital-based, case-control study of 1000 patients with vitiligo and 1000 vitiligo-free but age- and gender-matched controls. Two single nucleotide polymorphisms of the AHR gene (rs10249788 and rs2066853) were selected and genotyped using a polymerase chain reaction-restriction fragment length polymorphism method. RESULTS A statistically significantly decreased risk of vitiligo was found to be associated with the TT and CT genotypes of rs10249788 [odds ratio (OR) 0·59, 95% confidence interval (CI) 0·38-0·93; P = 0·028 and OR 0·82, 95% CI 0·68-0·98; P = 0·032, respectively] as well as among subgroups: male, active, nonsegmental vitiligo, and onset age ≤ 20 years. Moreover, subjects with the combined (CT + TT)/GG genotype or T/G haplotype (rs10249788/rs2066853) showed a decreased risk for vitiligo (OR 0·57, 95% CI 0·37-0·87, P = 0·009 and OR 0·78, 95% CI 0·64-0·96, P = 0·033, respectively). CONCLUSIONS These results suggest that the T allele of rs10249788 located in the promoter of the AHR gene is associated with a protective effect on vitiligo in Han Chinese populations.
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Affiliation(s)
- X-W Wang
- Department of Dermatology, Fourth Military Medical University, Xi'an, Shaanxi, China
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13
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Englert NA, Turesky RJ, Han W, Bessette EE, Spivack SD, Caggana M, Spink DC, Spink BC. Genetic and epigenetic regulation of AHR gene expression in MCF-7 breast cancer cells: role of the proximal promoter GC-rich region. Biochem Pharmacol 2012; 84:722-35. [PMID: 22728919 DOI: 10.1016/j.bcp.2012.06.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 06/14/2012] [Accepted: 06/14/2012] [Indexed: 10/28/2022]
Abstract
The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, contributes to carcinogenesis through its role in the regulation of cytochrome P450 1 (CYP1)-catalyzed metabolism of carcinogens. Here, we investigated genetic and epigenetic mechanisms that affect AhR expression. Analyses of the human AHR proximal promoter in MCF-7 human breast cancer cells using luciferase assays and electrophoretic mobility shift assays revealed multiple specificity protein (Sp) 1 binding sequences that are transcriptional activators in vitro. The regulation of AhR expression was evaluated in long-term estrogen exposed (LTEE) MCF-7 cells, which showed increased AhR expression, enhanced CYP1 inducibility, and increased capacity to form DNA adducts when exposed to the dietary carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine. The increased AhR expression in LTEE cells was found not to result from increased mRNA stability, differential RNA processing, or decreased DNA methylation. Analysis of the AHR proximal promoter region using chromatin immunoprecipitation confirmed that enhanced expression of AhR in LTEE cells involves changes in histone modifications, notably decreased trimethylation of histone 3, lysine 27. Upon further examination of the GC-rich Sp1-binding region, we confirmed that it contains a polymorphic (GGGGC)(n) repeat. In a population of newborns from New York State, the allele frequency of (GGGGC)(n) was n = 4 > 5 ≫ 6, 2. Circular dichroism spectroscopy revealed the ability of sequences of this GC-rich region to form guanine-quadruplex structures in vitro. These studies revealed multiple levels at which AhR expression may be controlled, and offer additional insights into mechanisms regulating AhR expression that can ultimately impact carcinogenesis.
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Affiliation(s)
- Neal A Englert
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
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14
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PPARalpha transcriptionally induces AhR expression in Caco-2, but represses AhR pro-inflammatory effects. Biochem Biophys Res Commun 2007; 364:896-901. [PMID: 17963696 DOI: 10.1016/j.bbrc.2007.10.084] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Accepted: 10/16/2007] [Indexed: 11/21/2022]
Abstract
In this work we demonstrate that Caco-2 cell treatment with WY-14643 (a potent PPARalpha agonist) causes an increase in AhR expression. Luciferase assays and directed mutagenesis experiments showed that induction mainly occurred at transcriptional level and involved a PPRE site located within the AhR promoter. These results were further confirmed by the use of PPARalpha knockout mice in which AhR induction by WY14643 was abrogated. In addition to CYP1 regulation, AhR has been described as being involved in inflammation, so we also studied the effect of AhR regulation by PPARalpha on the expression of some inflammation target genes. 3-Methylcholanthrene (a potent AhR agonist) increased the expression (mRNA) of the major inflammatory targets IL-1beta and MMP9. WY-14643 co-treatment abrogated the 3-methylcholanthrene pro-inflammatory effect. Hence the anti-inflammatory effect of PPARalpha overrides the pro-inflammatory effect of AhR.
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15
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Baumgart A, Schmidt M, Schmitz HJ, Schrenk D. Natural furocoumarins as inducers and inhibitors of cytochrome P450 1A1 in rat hepatocytes. Biochem Pharmacol 2005; 69:657-67. [PMID: 15670584 DOI: 10.1016/j.bcp.2004.11.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2004] [Accepted: 11/22/2004] [Indexed: 11/18/2022]
Abstract
Furocoumarins are natural plant constituents present in medicinal plants and in a variety of foods such as grapefruit juice. They are phototoxic and act as potent inhibitors of drug metabolism. We have investigated the interaction of four furocoumarins angelicin, bergamottin, isopimpinellin, and 8-methoxypsoralen with the expression and activity of aryl hydrocarbon receptor (AhR)-regulated CYP1A1 in rat hepatocytes in primary culture, both in the presence and absence of light. In intact hepatocytes pretreated with 2,3,7,8-tetrachlorodibenzo-p-dioxin and in microsomes isolated thereof, all furocoumarins tested acted as potent inhibitors of CYP1A1 activity bergamottin being the most potent inhibitor in microsomes with an IC(50) of 10 nM in the presence and 60 nM in the absence of light. 8-Methoxypsoralen and angelicin led to a significant induction of CYP1A1 mRNA in hepatocytes, while all furocoumarins except bergamottin increased xenobiotic-responsive element-driven reporter gene expression in transfected H4IIE rat hepatoma cells when light was excluded. Furthermore, all furocoumarins tested induced the expression of endogenous, immunoreactive CYP1A1 protein, primarily in the dark. In conclusion, our results demonstrate that individual furocoumarins present in food and medicinal plants can interfere with AhR-regulated CYP1A1 expression and activity in at least three major ways, i.e., (i) act as highly potent inhibitors of the catalytic activity of CYP1A1 both in the presence and absence of light, (ii) induce CYP1A1 gene expression in the absence of light via activation of the AhR, and (iii) induce CYP1A1 gene expression without activation of the AhR.
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Affiliation(s)
- Annette Baumgart
- Food Chemistry and Environmental Toxicology, University of Kaiserslautern, Erwin-Schroedinger-Strasse 52, D-67663 Kaiserslautern, Germany
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16
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Fukushima-Uesaka H, Sai K, Maekawa K, Koyano S, Kaniwa N, Ozawa S, Kawamoto M, Kamatani N, Komamura K, Kamakura S, Kitakaze M, Tomoike H, Ueno K, Minami H, Ohtsu A, Shirao K, Yoshida T, Saijo N, Saito Y, Sawada JI. Genetic Variations of the AHR Gene Encoding Aryl Hydrocarbon Receptor in a Japanese Population. Drug Metab Pharmacokinet 2004; 19:320-6. [PMID: 15499202 DOI: 10.2133/dmpk.19.320] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aryl hydrocarbon receptor (AhR), encoded by the AHR gene, is a transcriptional factor that induces various drug metabolizing enzymes in response to diverse endogenous and exogenous ligands. In order to identify genetic variations of the AHR gene, genomic DNA from 242 Japanese individuals was sequenced. We identified 32 single nucleotide variations, including 25 novel ones [7 were in the coding exons, 7 in the introns, 1 in the 5'-untranslated region (UTR), 5 in the 3'-UTR, 2 in the 5'-flanking region, and 3 in the 3'-flanking region] and a GGGGC repeat polymorphism (a novel microsatellite marker) in the promoter region. The novel nonsynonymous variations were 50A>C (Lys17Thr), 1202A>G (Lys401Arg), 1459A>G (Asn487Asp), and 1541T>C (Ile514Thr). The allele frequencies were 0.010 for 1459A>G (Asn487Asp) and 0.002 for the other 3 variations. Also detected in this analysis was the known nonsynonymous single nucleotide polymorphism 1661G>A (Arg554Lys) at a 0.444 frequency.
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