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Ma Z, Li Z, Mao Y, Ye J, Liu Z, Wang Y, Wei C, Cui J, Liu Z, Liang X. AhR diminishes the efficacy of chemotherapy via suppressing STING dependent type-I interferon in bladder cancer. Nat Commun 2023; 14:5415. [PMID: 37670034 PMCID: PMC10480448 DOI: 10.1038/s41467-023-41218-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 08/28/2023] [Indexed: 09/07/2023] Open
Abstract
The induction of type-I interferons (IFN-Is) is important for the efficacy of chemotherapy. By investigating the role of amino acids in regulation of IFN-I production under chemo-drug treatment in bladder cancer (BC) cells, we find an inherent AhR-dependent negative feedback to restrain STING signaling and IFN-I production. Mechanistically, in a ligand dependent manner, AhR bridges STING and CUL4B/RBX1 E3 ligase complex, facilitating STING degradation through ubiquitin-proteasome pathway. Inhibition of AhR increases STING levels and reduces tumor growth under cisplatin or STING agonist treatment. Endogenous AhR ligands are mainly consisted of tryptophan (Trp) metabolites; dietary Trp restriction, blocking the key Trp metabolism rate-limiting enzyme IDO1 or inhibition of cellular Trp importation also show similar effect as AhR inhibition. Clinically, BC patients with higher intratumoral expression of AhR or stronger intratumoral Trp metabolism (higher IDO1 or Kyn levels) that lead to higher AhR activation show worse response rate to neoadjuvant chemotherapy (NAC).
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Affiliation(s)
- Zikun Ma
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China
| | - Zhiyong Li
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China
| | - Yize Mao
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China
- Department of Pancreatobiliary Surgery, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China
| | - Jingwei Ye
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China
| | - Zefu Liu
- Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, P. R. China
| | - Yuzhao Wang
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China
| | - Chen Wei
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Jun Cui
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, P. R. China.
| | - Zhuowei Liu
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China.
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China.
- Sun Yat-sen University Cancer Center Gansu Hospital, Lanzhou, 730050, P. R. China.
| | - Xiaoyu Liang
- State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China.
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, P. R. China.
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2
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Zhang W, Xie HQ, Li Y, Zhou M, Zhou Z, Wang R, Hahn ME, Zhao B. The aryl hydrocarbon receptor: A predominant mediator for the toxicity of emerging dioxin-like compounds. JOURNAL OF HAZARDOUS MATERIALS 2022; 426:128084. [PMID: 34952507 PMCID: PMC9039345 DOI: 10.1016/j.jhazmat.2021.128084] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/29/2021] [Accepted: 12/12/2021] [Indexed: 06/01/2023]
Abstract
The aryl hydrocarbon receptor (AHR) is a member of the basic helix-loop-helix/Per-ARNT-Sim (bHLH-PAS) family of transcription factors and has broad biological functions. Early after the identification of the AHR, most studies focused on its roles in regulating the expression of drug-metabolizing enzymes and mediating the toxicity of dioxins and dioxin-like compounds (DLCs). Currently, more diverse functions of AHR have been identified, indicating that AHR is not just a dioxin receptor. Dioxins and DLCs occur ubiquitously and have diverse health/ecological risks. Additional research is required to identify both shared and compound-specific mechanisms, especially for emerging DLCs such as polyhalogenated carbazoles (PHCZs), polychlorinated diphenyl sulfides (PCDPSs), and others, of which only a few investigations have been performed at present. Many of the toxic effects of emerging DLCs were observed to be predominantly mediated by the AHR because of their structural similarity as dioxins, and the in vitro TCDD-relative potencies of certain emerging DLC congeners are comparable to or even greater than the WHO-TEFs of OctaCDD, OctaCDF, and most coplanar PCBs. Due to the close relationship between AHR biology and environmental science, this review begins by providing novel insights into AHR signaling (canonical and non-canonical), AHR's biochemical properties (AHR structure, AHR-ligand interaction, AHR-DNA binding), and the variations during AHR transactivation. Then, AHR ligand classification and the corresponding mechanisms are discussed, especially the shared and compound-specific, AHR-mediated effects and mechanisms of emerging DLCs. Accordingly, a series of in vivo and in vitro toxicity evaluation methods based on the AHR signaling pathway are reviewed. In light of current advances, future research on traditional and emerging DLCs will enhance our understanding of their mechanisms, toxicity, potency, and ecological impacts.
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Affiliation(s)
- Wanglong Zhang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong 273165, China
| | - Heidi Qunhui Xie
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunping Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mingxi Zhou
- Biology Centre of the Czech Academy of Sciences v.v.i, Institute of Plant Molecular Biology, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Zhiguang Zhou
- State Environmental Protection Key Laboratory of Dioxin Pollution Control, National Research Center for Environmental Analysis and Measurement, Beijing 100029, China
| | - Renjun Wang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong 273165, China
| | - Mark E Hahn
- Biology Department, Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA 02543, USA; Boston University Superfund Research Program, Boston University, Boston, MA 02118, USA
| | - Bin Zhao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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3
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O'Donnell EF, Jang HS, Liefwalker DF, Kerkvliet NI, Kolluri SK. Discovery and Mechanistic Characterization of a Select Modulator of AhR-regulated Transcription (SMAhRT) with Anti-cancer Effects. Apoptosis 2021; 26:307-322. [PMID: 33893898 DOI: 10.1007/s10495-021-01666-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2021] [Indexed: 02/07/2023]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor and a member of the bHLH/PAS (basic Helix-Loop-Helix/Per-Arnt-Sim) family of proteins. The AhR was cloned and characterized for its role in mediating the toxicity of dioxins. Subsequent research has identified the role of AhR in suppression of cancer cell growth. We hypothesized that the AhR is a molecular target for therapeutic intervention in cancer, and that activation of the AhR by unique AhR ligands in cancer cells could have anti-cancer effects including induction of cell death. This study describes the discovery and characterization of a new class of anti-cancer agents targeting the AhR, that we designate as Select Modulators of AhR-regulated Transcription (SMAhRTs). We employed two independent small molecule screening approaches to identify potential SMAhRTs. We report the identification of CGS-15943 that activates AhR signaling and induces apoptosis in an AhR-dependent manner in liver and breast cancer cells. Investigation of the downstream signaling pathway of this newly identified SMAhRT revealed upregulation of Fas-ligand (FasL), which is required for AhR-mediated apoptosis. Our results provide a basis for further development of a new class of anti-cancer therapeutics targeting an underappreciated molecular target, the AhR.
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Affiliation(s)
- Edmond Francis O'Donnell
- Cancer Research Laboratory, Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR, 97331, USA
- Department of Orthopaedic Surgery, University of California Davis Medical Center, Davis, CA, USA
| | - Hyo Sang Jang
- Cancer Research Laboratory, Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR, 97331, USA
| | - Daniel F Liefwalker
- Cancer Research Laboratory, Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR, 97331, USA
- Department of Molecular and Medical Genetics, School of Medicine, Oregon Health and Science University, Portland, OR, USA
| | - Nancy I Kerkvliet
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR, 97331, USA
- The Pacific Northwest Center for Translational Environmental Health Research, Oregon State University, Corvallis, OR, 97331, USA
| | - Siva Kumar Kolluri
- Cancer Research Laboratory, Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR, 97331, USA.
- Linus Pauling Institute, Oregon State University, Corvallis, OR, 97331, USA.
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, 97331, USA.
- The Pacific Northwest Center for Translational Environmental Health Research, Oregon State University, Corvallis, OR, 97331, USA.
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Kuzmina NS, Luong TM, Rubanovich AV. Changes in DNA Methylation Induced by Dioxins and Dioxin-Like Compounds as Potential Predictor of Disease Risk. RUSS J GENET+ 2020. [DOI: 10.1134/s1022795420100063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Rhon Calderón EA, Galarza RA, Faletti AG. 3-Methylcholanthrene impacts on the female germ cells of rats without causing systemic toxicity. Toxicology 2020; 429:152328. [DOI: 10.1016/j.tox.2019.152328] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/16/2019] [Accepted: 10/31/2019] [Indexed: 12/31/2022]
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6
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Dolciami D, Ballarotto M, Gargaro M, López-Cara LC, Fallarino F, Macchiarulo A. Targeting Aryl hydrocarbon receptor for next-generation immunotherapies: Selective modulators (SAhRMs) versus rapidly metabolized ligands (RMAhRLs). Eur J Med Chem 2019; 185:111842. [PMID: 31727470 DOI: 10.1016/j.ejmech.2019.111842] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/30/2019] [Accepted: 10/30/2019] [Indexed: 12/12/2022]
Abstract
Aryl Hydrocarbon Receptor (AhR) constitutes a major network hub of genomic and non-genomic signaling pathways, connecting host's immune cells to environmental factors. It shapes innate and adaptive immune processes to environmental stimuli with species-, cell- and tissue-type dependent specificity. Although an ever increasing number of studies has thrust AhR into the limelight as attractive target for the development of next-generation immunotherapies, concerns exist on potential safety issues associated with small molecule modulation of the receptor. Selective AhR modulators (SAhRMs) and rapidly metabolized AhR ligands (RMAhRLs) are two classes of receptor agonists that are emerging as interesting lead compounds to bypass AhR-related toxicity in favor of therapeutic effects. In this article, we discuss SAhRMs and RMAhRLs reported in literature, covering concepts underlying their definitions, specific binding modes, structure-activity relationships and AhR-mediated functions.
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Affiliation(s)
- Daniela Dolciami
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo, 1, 06123, Perugia, Italy
| | - Marco Ballarotto
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo, 1, 06123, Perugia, Italy
| | - Marco Gargaro
- Department of Experimental Medicine, University of Perugia, Piazz.le Gambuli, 1, 06132, Perugia, Italy
| | - Luisa Carlota López-Cara
- Department of Pharmaceutical & Organic Chemistry, Faculty of Pharmacy, University of Granada, 18010, Granada, Spain
| | - Francesca Fallarino
- Department of Experimental Medicine, University of Perugia, Piazz.le Gambuli, 1, 06132, Perugia, Italy
| | - Antonio Macchiarulo
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo, 1, 06123, Perugia, Italy.
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Viluksela M, Pohjanvirta R. Multigenerational and Transgenerational Effects of Dioxins. Int J Mol Sci 2019; 20:E2947. [PMID: 31212893 PMCID: PMC6627869 DOI: 10.3390/ijms20122947] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 12/12/2022] Open
Abstract
Dioxins are ubiquitous and persistent environmental contaminants whose background levels are still reason for concern. There is mounting evidence from both epidemiological and experimental studies that paternal exposure to the most potent congener of dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), can lower the male/female ratio of offspring. Moreover, in laboratory rodents and zebrafish, TCDD exposure of parent animals has been reported to result in reduced reproductive performance along with other adverse effects in subsequent generations, foremost through the paternal but also via the maternal germline. These impacts have been accompanied by epigenetic alterations in placenta and/or sperm cells, including changes in methylation patterns of imprinted genes. Here, we review recent key studies in this field with an attempt to provide an up-to-date picture of the present state of knowledge to the reader. These studies provide biological plausibility for the potential of dioxin exposure at a critical time-window to induce epigenetic alterations across multiple generations and the significance of aryl hydrocarbon receptor (AHR) in mediating these effects. Currently available data do not allow to accurately estimate the human health implications of these findings, although epidemiological evidence on lowered male/female ratio suggests that this effect may take place at realistic human exposure levels.
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Affiliation(s)
- Matti Viluksela
- School of Pharmacy and Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
- Environmental Health Unit, National Institute for Health and Welfare, P.O. Box 95, FI-70701 Kuopio, Finland.
| | - Raimo Pohjanvirta
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 66, FI-00014 Helsinki, Finland.
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Identification of the novel role of butyrate as AhR ligand in human intestinal epithelial cells. Sci Rep 2019; 9:643. [PMID: 30679727 PMCID: PMC6345974 DOI: 10.1038/s41598-018-37019-2] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/28/2018] [Indexed: 12/18/2022] Open
Abstract
The ligand activated transcription factor, aryl hydrocarbon receptor (AhR) emerged as a critical regulator of immune and metabolic processes in the gastrointestinal tract. In the gut, a main source of AhR ligands derives from commensal bacteria. However, many of the reported microbiota-derived ligands have been restricted to indolyl metabolites. Here, by screening commensal bacteria supernatants on an AhR reporter system expressed in human intestinal epithelial cell line (IEC), we found that the short chain fatty acid (SCFA) butyrate induced AhR activity and the transcription of AhR-dependent genes in IECs. We showed that AhR ligand antagonists reduced the effects of butyrate on IEC suggesting that butyrate could act as a ligand of AhR, which was supported by the nuclear translocation of AhR induced by butyrate and in silico structural modelling. In conclusion, our findings suggest that (i) butyrate activates AhR pathway and AhR-dependent genes in human intestinal epithelial cell-lines (ii) butyrate is a potential ligand for AhR which is an original mechanism of gene regulation by SCFA.
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Chitrala KN, Yang X, Nagarkatti P, Nagarkatti M. Comparative analysis of interactions between aryl hydrocarbon receptor ligand binding domain with its ligands: a computational study. BMC STRUCTURAL BIOLOGY 2018; 18:15. [PMID: 30522477 PMCID: PMC6282305 DOI: 10.1186/s12900-018-0095-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 11/07/2018] [Indexed: 12/22/2022]
Abstract
BACKGROUND Aryl hydrocarbon receptor (AhR) ligands may act as potential carcinogens or anti-tumor agents. Understanding how some of the residues in AhR ligand binding domain (AhRLBD) modulate their interactions with ligands would be useful in assessing their divergent roles including toxic and beneficial effects. To this end, we have analysed the nature of AhRLBD interactions with 2,3,7,8-tetrachlorodibenzo-ρ-dioxin (TCDD), 6-formylindolo[3,2-b]carbazole (FICZ), indole-3-carbinol (I3C) and its degradation product, 3,3'-diindolylmethane (DIM), Resveratrol (RES) and its analogue, Piceatannol (PTL) using molecular modeling approach followed by molecular dynamic simulations. RESULTS Results showed that each of the AhR ligands, TCDD, FICZ, I3C, DIM, RES and PTL affect the local and global conformations of AhRLBD. CONCLUSION The data presented in this study provide a structural understanding of AhR with its ligands and set the basis for its functions in several pathways and their related diseases.
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Affiliation(s)
- Kumaraswamy Naidu Chitrala
- Department of Pathology, Microbiology and Immunology, University of South Carolina, School of Medicine, Columbia, SC 29208 USA
| | - Xiaoming Yang
- Department of Pathology, Microbiology and Immunology, University of South Carolina, School of Medicine, Columbia, SC 29208 USA
| | - Prakash Nagarkatti
- Department of Pathology, Microbiology and Immunology, University of South Carolina, School of Medicine, Columbia, SC 29208 USA
| | - Mitzi Nagarkatti
- Department of Pathology, Microbiology and Immunology, University of South Carolina, School of Medicine, Columbia, SC 29208 USA
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Knutsen HK, Alexander J, Barregård L, Bignami M, Brüschweiler B, Ceccatelli S, Cottrill B, Dinovi M, Edler L, Grasl-Kraupp B, Hogstrand C, Nebbia CS, Oswald IP, Petersen A, Rose M, Roudot AC, Schwerdtle T, Vleminckx C, Vollmer G, Wallace H, Fürst P, Håkansson H, Halldorsson T, Lundebye AK, Pohjanvirta R, Rylander L, Smith A, van Loveren H, Waalkens-Berendsen I, Zeilmaker M, Binaglia M, Gómez Ruiz JÁ, Horváth Z, Christoph E, Ciccolallo L, Ramos Bordajandi L, Steinkellner H, Hoogenboom LR. Risk for animal and human health related to the presence of dioxins and dioxin-like PCBs in feed and food. EFSA J 2018; 16:e05333. [PMID: 32625737 PMCID: PMC7009407 DOI: 10.2903/j.efsa.2018.5333] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of dioxins (PCDD/Fs) and DL-PCBs in feed and food. The data from experimental animal and epidemiological studies were reviewed and it was decided to base the human risk assessment on effects observed in humans and to use animal data as supportive evidence. The critical effect was on semen quality, following pre- and postnatal exposure. The critical study showed a NOAEL of 7.0 pg WHO2005-TEQ/g fat in blood sampled at age 9 years based on PCDD/F-TEQs. No association was observed when including DL-PCB-TEQs. Using toxicokinetic modelling and taking into account the exposure from breastfeeding and a twofold higher intake during childhood, it was estimated that daily exposure in adolescents and adults should be below 0.25 pg TEQ/kg bw/day. The CONTAM Panel established a TWI of 2 pg TEQ/kg bw/week. With occurrence and consumption data from European countries, the mean and P95 intake of total TEQ by Adolescents, Adults, Elderly and Very Elderly varied between, respectively, 2.1 to 10.5, and 5.3 to 30.4 pg TEQ/kg bw/week, implying a considerable exceedance of the TWI. Toddlers and Other Children showed a higher exposure than older age groups, but this was accounted for when deriving the TWI. Exposure to PCDD/F-TEQ only was on average 2.4- and 2.7-fold lower for mean and P95 exposure than for total TEQ. PCDD/Fs and DL-PCBs are transferred to milk and eggs, and accumulate in fatty tissues and liver. Transfer rates and bioconcentration factors were identified for various species. The CONTAM Panel was not able to identify reference values in most farm and companion animals with the exception of NOAELs for mink, chicken and some fish species. The estimated exposure from feed for these species does not imply a risk.
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O'Donnell EF, Jang HS, Pearce M, Kerkvliet NI, Kolluri SK. The aryl hydrocarbon receptor is required for induction of p21cip1/waf1 expression and growth inhibition by SU5416 in hepatoma cells. Oncotarget 2018; 8:25211-25225. [PMID: 28424418 PMCID: PMC5421923 DOI: 10.18632/oncotarget.16056] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 02/06/2017] [Indexed: 11/25/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR) is a potential clinical target for cancer and autoimmune dysfunction. Identifying selective AhR modulators that produce desirable clinical outcomes represents an opportunity for developing new anti-cancer agents. Repurposing clinically-used drugs with established safety profiles that activate the AhR represents a good starting place to pursue this goal. In this study, we characterized the AhR-dependent effects of SU5416 (Semaxanib) following its identification in a small-molecule library screen. SU5416 potently activated AhR-dependent reporter genes, induced AhR nuclear localization, facilitated AhR-DNA binding, and increased, expression of its endogenous target genes. SU5416 significantly inhibited proliferation of Hepa1 hepatoma cells in an AhR-dependent manner, but did not induce apoptosis. SU5416 also inhibited the growth of human HepG2 liver cancer cells. The effects of SU5416 correlated with an increased G1 population and increased expression of cell cycle inhibitor p21cip1/waf1 at both the mRNA and protein level. Increased expression of p21cip1/waf1 by SU5416 required expression of both AhR and Arnt. In addition, evidence for long-term activation of the AhR in vivo by a single dose of SU5416 was identified by analyzing published microarray data. Our results provide support for continued investigation of the AhR as therapeutic for cancers such as hepatocellular carcinoma. In addition, our findings raise the possibility that some of the previously observed anti-proliferative effects of SU5416 may be due to activation of the AhR.
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Affiliation(s)
- Edmond F O'Donnell
- Cancer Research Laboratory, Oregon State University, Corvallis, Oregon, USA.,Department of Environmental and Molecular Toxicology, and Environmental Health Sciences Center, Oregon State University, Corvallis, Oregon, USA
| | - Hyo Sang Jang
- Cancer Research Laboratory, Oregon State University, Corvallis, Oregon, USA.,Department of Environmental and Molecular Toxicology, and Environmental Health Sciences Center, Oregon State University, Corvallis, Oregon, USA
| | - Martin Pearce
- Cancer Research Laboratory, Oregon State University, Corvallis, Oregon, USA.,Department of Environmental and Molecular Toxicology, and Environmental Health Sciences Center, Oregon State University, Corvallis, Oregon, USA
| | - Nancy I Kerkvliet
- Department of Environmental and Molecular Toxicology, and Environmental Health Sciences Center, Oregon State University, Corvallis, Oregon, USA
| | - Siva Kumar Kolluri
- Cancer Research Laboratory, Oregon State University, Corvallis, Oregon, USA.,Department of Environmental and Molecular Toxicology, and Environmental Health Sciences Center, Oregon State University, Corvallis, Oregon, USA
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12
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Abiko Y, Lin FY, Lee H, Puga A, Kumagai Y. Quinone-mediated induction of cytochrome P450 1A1 in HepG2 cells through increased interaction of aryl hydrocarbon receptor with aryl hydrocarbon receptor nuclear translocator. J Toxicol Sci 2017; 41:775-781. [PMID: 27853106 DOI: 10.2131/jts.41.775] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
While it has long been believed that benzenes and naphthalenes are unable to activate the aryl hydrocarbon receptor (AhR) because they are poor ligands, we recently reported that these quinoid metabolites upregulated cytochrome P450 1A1 (CYP1A1) in Hepa1c1c7 cells (Abiko et al., 2015). In the current study, AhR activation, measured with a bioluminescence-based cell free assay, was induced by 1,2-naphthoquinone (1,2-NQ), a metabolite of naphthalene. Consistent with this, 1,4-benzoquinone (1,4-BQ), tert-butyl-1,4-BQ, and 1,4-NQ, as well as 1,2-NQ, all electrophilic mono- and bi-cyclic quinones, upregulated CYP1A1 mRNA and protein in HepG2 cells, whereas their parent aromatic hydrocarbons had little effect. Furthermore, immunofluorescence analysis confirmed that these quinones enhanced translocation of AhR to the nucleus.
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Affiliation(s)
- Yumi Abiko
- Faculty of Medicine, University of Tsukuba
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13
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Xue Z, Li D, Yu W, Zhang Q, Hou X, He Y, Kou X. Mechanisms and therapeutic prospects of polyphenols as modulators of the aryl hydrocarbon receptor. Food Funct 2017; 8:1414-1437. [DOI: 10.1039/c6fo01810f] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Polyphenolic AhR modulators displayed concentration-, XRE-, gene-, species- and cell-specific agonistic/antagonistic activity.
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Affiliation(s)
- Zhaohui Xue
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Dan Li
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Wancong Yu
- Medical Plant Laboratory
- Tianjin Research Center of Agricultural Biotechnology
- Tianjin 3000381
- China
| | - Qian Zhang
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Xiaonan Hou
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Yulong He
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Xiaohong Kou
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
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Abiko Y, Puga A, Kumagai Y. Covalent binding of quinones activates the Ah receptor in Hepa1c1c7 cells. J Toxicol Sci 2016; 40:873-86. [PMID: 26558468 DOI: 10.2131/jts.40.873] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Highly reactive quinone species produced by photooxidation and/or metabolic activation of mono- or bi-aromatic hydrocarbons modulate cellular homeostasis and electrophilic signal transduction pathways through the covalent modification of proteins. Polycyclic aromatic hydrocarbons, but not mono- or bi-aromatic hydrocarbons, are well recognized as ligands for the aryl hydrocarbon receptor (AhR). However, quinone species produced from mono- and bi-aromatic hydrocarbons could potentially cause AhR activation. To clarify the AhR response to mono- and bi-aromatic hydrocarbon quinones, we studied Cyp1a1 (cytochrome P450 1A1) induction and AhR activation by these quinones. We detected Cyp1a1 induction during treatment with quinones in Hepa1c1c7 cells, but not their parent compounds. Nine of the twelve quinones with covalent binding capability for proteins induced Cyp1a1. Cyp1a1 induction mediated by 1,2-naphthoquinone (1,2-NQ), 1,4-NQ, 1,4-benzoquinone (1,4-BQ) and tert-butyl-1,4-BQ was suppressed by a specific AhR inhibitor and was not observed in c35 cells, which do not have a functional AhR. These quinones stimulated AhR nuclear translocation and interaction with the AhR nuclear translocator. Interestingly, 1,2-NQ covalently modified AhR, which was detected by an immunoprecipitation assay using a specific antibody against 1,2-NQ, resulting in enhancement of xenobiotic responsive element (XRE)-derived luciferase activity and binding of AhR to the Cyp1a1 promoter region. While mono- and bi-aromatic hydrocarbons are generally believed to be poor ligands for AhR and hence unable to induce Cyp1a1, our study suggests that the quinones of these molecules are able to modify AhR and activate the AhR/XRE pathway, thereby inducing Cyp1a1. Since we previously reported that 1,2-NQ and tert-butyl-1,4-BQ also activate NF-E2-related factor 2, it seems likely that some of quinones are bi-functional inducers for phase-I and phase-II reaction of xenobiotics.
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Affiliation(s)
- Yumi Abiko
- Faculty of Medicine, University of Tsukuba
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15
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Jackson DP, Joshi AD, Elferink CJ. Ah Receptor Pathway Intricacies; Signaling Through Diverse Protein Partners and DNA-Motifs. Toxicol Res (Camb) 2015; 4:1143-1158. [PMID: 26783425 PMCID: PMC4714567 DOI: 10.1039/c4tx00236a] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The Ah receptor is a transcription factor that modulates gene expression via interactions with multiple protein partners; these are reviewed, including the novel NC-XRE pathway involving KLF6.
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16
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Nuti R, Gargaro M, Matino D, Dolciami D, Grohmann U, Puccetti P, Fallarino F, Macchiarulo A. Ligand Binding and Functional Selectivity of l-Tryptophan Metabolites at the Mouse Aryl Hydrocarbon Receptor (mAhR). J Chem Inf Model 2014; 54:3373-83. [DOI: 10.1021/ci5005459] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Affiliation(s)
- Roberto Nuti
- Department of Pharmaceutical Sciences and ‡Department of Experimental
Medicine, Università di Perugia, via del Liceo 1, 06123 Perugia, Italy
| | - Marco Gargaro
- Department of Pharmaceutical Sciences and ‡Department of Experimental
Medicine, Università di Perugia, via del Liceo 1, 06123 Perugia, Italy
| | - Davide Matino
- Department of Pharmaceutical Sciences and ‡Department of Experimental
Medicine, Università di Perugia, via del Liceo 1, 06123 Perugia, Italy
| | - Daniela Dolciami
- Department of Pharmaceutical Sciences and ‡Department of Experimental
Medicine, Università di Perugia, via del Liceo 1, 06123 Perugia, Italy
| | - Ursula Grohmann
- Department of Pharmaceutical Sciences and ‡Department of Experimental
Medicine, Università di Perugia, via del Liceo 1, 06123 Perugia, Italy
| | - Paolo Puccetti
- Department of Pharmaceutical Sciences and ‡Department of Experimental
Medicine, Università di Perugia, via del Liceo 1, 06123 Perugia, Italy
| | - Francesca Fallarino
- Department of Pharmaceutical Sciences and ‡Department of Experimental
Medicine, Università di Perugia, via del Liceo 1, 06123 Perugia, Italy
| | - Antonio Macchiarulo
- Department of Pharmaceutical Sciences and ‡Department of Experimental
Medicine, Università di Perugia, via del Liceo 1, 06123 Perugia, Italy
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Hu Q, He G, Zhao J, Soshilov A, Denison MS, Zhang A, Yin H, Fraccalvieri D, Bonati L, Xie Q, Zhao B. Ginsenosides are novel naturally-occurring aryl hydrocarbon receptor ligands. PLoS One 2013; 8:e66258. [PMID: 23776647 PMCID: PMC3679084 DOI: 10.1371/journal.pone.0066258] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 05/03/2013] [Indexed: 11/19/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor that mediates many of the biological and toxicological actions of structurally diverse chemicals. In this study, we examined the ability of a series of ginsenosides extracted from ginseng, a traditional Chinese medicine, to bind to and activate/inhibit the AHR and AHR signal transduction. Utilizing a combination of ligand and DNA binding assays, molecular docking and reporter gene analysis, we demonstrated the ability of selected ginsenosides to directly bind to and activate the guinea pig cytosolic AHR, and to stimulate/inhibit AHR-dependent luciferase gene expression in a recombinant guinea pig cell line. Comparative studies revealed significant species differences in the ability of ginsenosides to stimulate AHR-dependent gene expression in guinea pig, rat, mouse and human cell lines. Not only did selected ginsenosides preferentially activate the AHR from one species and not others, mouse cell line was also significantly less responsive to these chemicals than rat and guinea pig cell lines, but the endogenous gene CYP1A1 could still be inducted in mouse cell line. Overall, the ability of these compounds to stimulate AHR signal transduction demonstrated that these ginsenosides are a new class of naturally occurring AHR agonists.
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Affiliation(s)
- Qin Hu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Guochun He
- Department of Environmental Toxicology, University of California, Davis, California, United States of America
| | - Jing Zhao
- Department of Environmental Toxicology, University of California, Davis, California, United States of America
| | - Anatoly Soshilov
- Department of Environmental Toxicology, University of California, Davis, California, United States of America
| | - Michael S. Denison
- Department of Environmental Toxicology, University of California, Davis, California, United States of America
| | - Aiqian Zhang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Huijun Yin
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Domenico Fraccalvieri
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Milan, Italy
| | - Laura Bonati
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Milan, Italy
| | - Qunhui Xie
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Bin Zhao
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
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18
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Wang BJ, Wu PY, Lu YC, Chang CH, Lin YC, Tsai TC, Hsu MC, Lee H. Establishment of a cell-free bioassay for detecting dioxin-like compounds. Toxicol Mech Methods 2013; 23:464-70. [DOI: 10.3109/15376516.2013.781254] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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19
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Nanez A, Ramos IN, Ramos KS. A mutant Ahr allele protects the embryonic kidney from hydrocarbon-induced deficits in fetal programming. ENVIRONMENTAL HEALTH PERSPECTIVES 2011; 119:1745-1753. [PMID: 21803694 PMCID: PMC3261986 DOI: 10.1289/ehp.1103692] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 07/29/2011] [Indexed: 05/27/2023]
Abstract
BACKGROUND The use of experimental model systems has expedited the elucidation of pathogenetic mechanisms of renal developmental disease in humans and the identification of genes that orchestrate developmental programming during nephrogenesis. OBJECTIVES We conducted studies to evaluate the role of AHR polymorphisms in the disruption of renal developmental programming by benzo(a)pyrene (BaP). METHODS We used metanephric cultures of C57BL/6J (C57) mice expressing the Ahr(b-1) allele and B6.D2N-Ahr(d)/J (D2N) mice expressing a mutant allele deficient in ligand binding (Ahr(d)) to investigate molecular mechanisms of renal development. Deficits in fetal programming were evaluated in the offspring of pregnant mice treated with BaP during nephrogenesis. RESULTS Hydrocarbon challenge of metanephri from C57 mice altered Wilms' tumor suppressor gene (Wt1) mRNA splice variant ratios and reduced mRNAs of the Wt1 transcriptional targets syndecan-1 (Sdc1) paired box gene 2 (Pax2), epidermal growth factor receptor (Egfr), and retinoic acid receptor, alpha (Rarα). These changes correlated with down-regulation of effectors of differentiation [secreted frizzled-related sequence protein 1 (Sfrp1), insulin-like growth factor 1 receptor (Igf1r), wingless-related MMTV-integration site 4 (Wnt4), Lim homeobox protein 1 (Lhx1), E-cadherin]. In contrast, metanephri from D2N mice were spared hydrocarbon-induced changes in Wt1 splice variant ratios and deficits of differentiation. We observed similar patterns of dysmorphogenesis and progressive loss of renal function at postnatal weeks 7 and 52 in the offspring of pregnant C57 but not D2N mice gavaged with 0.1 or 0.5 mg/kg BaP on gestation days 10-13. CONCLUSIONS These findings support a functional link between AHR and WT1 in the regulation of renal morphogenesis and raise important questions about the contribution of human AHR polymorphisms to the fetal origins of adult-onset kidney disease.
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Affiliation(s)
- Adrian Nanez
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky 40292, USA
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20
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Denison MS, Soshilov AA, He G, DeGroot DE, Zhao B. Exactly the same but different: promiscuity and diversity in the molecular mechanisms of action of the aryl hydrocarbon (dioxin) receptor. Toxicol Sci 2011; 124:1-22. [PMID: 21908767 DOI: 10.1093/toxsci/kfr218] [Citation(s) in RCA: 563] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Ah receptor (AhR) is a ligand-dependent transcription factor that mediates a wide range of biological and toxicological effects that result from exposure to a structurally diverse variety of synthetic and naturally occurring chemicals. Although the overall mechanism of action of the AhR has been extensively studied and involves a classical nuclear receptor mechanism of action (i.e., ligand-dependent nuclear localization, protein heterodimerization, binding of liganded receptor as a protein complex to its specific DNA recognition sequence and activation of gene expression), details of the exact molecular events that result in most AhR-dependent biochemical, physiological, and toxicological effects are generally lacking. Ongoing research efforts continue to describe an ever-expanding list of ligand-, species-, and tissue-specific spectrum of AhR-dependent biological and toxicological effects that seemingly add even more complexity to the mechanism. However, at the same time, these studies are also identifying and characterizing new pathways and molecular mechanisms by which the AhR exerts its actions and plays key modulatory roles in both endogenous developmental and physiological pathways and response to exogenous chemicals. Here we provide an overview of the classical and nonclassical mechanisms that can contribute to the differential sensitivity and diversity in responses observed in humans and other species following ligand-dependent activation of the AhR signal transduction pathway.
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Affiliation(s)
- Michael S Denison
- Department of Environmental Toxicology, University of California, Davis, California 95616, USA.
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21
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Barreiro KA, Di Yorio MP, Artillo-Guida RD, Paz DA, Faletti AG. Daily treatment with α-naphthoflavone enhances follicular growth and ovulation rate in the rat. Toxicol Appl Pharmacol 2011; 252:11-7. [DOI: 10.1016/j.taap.2011.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2010] [Revised: 01/12/2011] [Accepted: 01/13/2011] [Indexed: 10/18/2022]
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22
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Procházková J, Kozubík A, Machala M, Vondráček J. Differential effects of indirubin and 2,3,7,8-tetrachlorodibenzo-p-dioxin on the aryl hydrocarbon receptor (AhR) signalling in liver progenitor cells. Toxicology 2010; 279:146-54. [PMID: 20951181 DOI: 10.1016/j.tox.2010.10.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 09/21/2010] [Accepted: 10/07/2010] [Indexed: 11/29/2022]
Abstract
In the present study, we investigated the effects of potential endogenous ligand indirubin on the aryl hydrocarbon receptor (AhR) signalling, with a focus on the AhR-dependent gene expression and cell cycle progression in rat liver progenitor cells, and compared them with the effects of a model toxic AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The low (picomolar and nanomolar) doses of indirubin, corresponding to expected endogenous levels, induced a transient translocation of AhR to the nucleus, while high (micromolar) doses induced a long-term AhR nuclear translocation, followed by its degradation, similar to the effects of TCDD. Whereas high doses of indirubin recruited AhR/ARNT1 dimer to rat Cyp1a1 promoter, the low doses did not induce its DNA binding, as revealed by the chromatin immunoprecipitation assay. This corresponded with the fact that the micromolar doses of indirubin significantly increased Cyp1a1/1b1 mRNA in a way similar to TCDD, while the low doses of indirubin were only poor inducers of Cyp1a1/1b1 expression. Comparable patterns of expression were observed also for other AhR gene targets, such as Nqo1 and Nrf2. Also, only micromolar doses of indirubin were able to mimic the effects of TCDD on cell cycle and proliferation of liver progenitor cells or hepatoma cells. Nevertheless, indirubin at low concentrations may have unique effects on gene expression in non-tumorigenic cells. Although both TCDD and the high doses of indirubin repressed plakoglobin (Jup) expression, the picomolar doses of indirubin, unlike the equimolar doses of TCDD, increased mRNA levels of this important desmosomal and adherens junctions constituent. These present data suggest that the outcome of AhR activation induced by indirubin at concentrations expected in vivo may differ from the AhR signalling triggered by exogenous toxic ligands, such as TCDD.
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Affiliation(s)
- Jiřina Procházková
- Department of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 61265 Brno, Czech Republic
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23
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Funatake CJ, Ao K, Suzuki T, Murai H, Yamamoto M, Fujii-Kuriyama Y, Kerkvliet NI, Nohara K. Expression of constitutively-active aryl hydrocarbon receptor in T-cells enhances the down-regulation of CD62L, but does not alter expression of CD25 or suppress the allogeneic CTL response. J Immunotoxicol 2010; 6:194-203. [PMID: 19635034 DOI: 10.1080/15476910903124454] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Activation of aryl hydrocarbon receptor (AhR) by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in T-cells is required for TCDD-induced suppression of the allogeneic CTL response and for induction of CD25(hi)CD62L(low) adaptive regulatory T-cells. Here, the ability of a constitutively-active AhR (CA-AhR) expressed in T-cells alone to replicate the effects of TCDD was examined. The response of CA-AhR-expressing B6 donor T-cells in B6xD2F1 mice was compared to the response of wild-type B6 donor T-cells in B6xD2F1 mice given a single dose of TCDD. Expression of CA-AhR in donor T-cells enhanced the down-regulation of CD62L on Day 2 after injection, similar to a single oral dose of TCDD, but did not induce up-regulation of CD25 on Day 2 or affect CTL activity on Day 10. This suggests that activation of AhR in T-cells alone may not be sufficient to alter T-cell responses in this acute graft-versus-host (GvH) model. Since host APC are responsible for activating the donor T-cells, we examined the influence of the F1 host's AhR on donor T-cell responses by creating an AhR(-/-) B6xD2F1 host that had a greatly diminished AhR response to TCDD compared to wild-type F1 mice. As in AhR(+/+) B6xD2F1 mice, the CTL response in AhR(-/-) B6xD2F1 mice was completely suppressed by TCDD. This suggests that either CA-AhR dose not fully replicate the function of TCDD-activated AhR in suppression of the CTL response, or that minimal activation of AhR in host cells is required to combine with activation of AhR in T-cells to elicit the immunosuppressive effects of TCDD.
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Affiliation(s)
- Castle J Funatake
- Environmental Health Sciences Division, National Institute for Environmental Studies, Tsukuba 305-8506, Japan
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24
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Gasiewicz TA, Singh KP, Casado FL. The aryl hydrocarbon receptor has an important role in the regulation of hematopoiesis: implications for benzene-induced hematopoietic toxicity. Chem Biol Interact 2009; 184:246-51. [PMID: 19896476 DOI: 10.1016/j.cbi.2009.10.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 10/22/2009] [Accepted: 10/24/2009] [Indexed: 10/20/2022]
Abstract
The aryl hydrocarbon receptor (AhR) belongs to the basic helix-loop-helix (bHLH) Per-Arnt-Sim (PAS) family of transcription factors. Many of these proteins are involved in regulating responses to signals in the tissue environment such as hypoxia, oxidation-reduction status, and circadian rhythms. Although the AhR is well studied as a mediator of the toxicity of certain xenobiotics, the normal physiological function remains unknown. However, accumulating data support a hypothesis that the AhR has an important function in the regulation of hematopoietic stem cells (HSCs). Persistent AhR activation by dioxin, a potent xenobiotic AhR agonist, results in altered numbers and function of HSCs in mouse bone marrow. Analysis of HSCs from AhR null-allele mice also indicates that lack of AhR expression results in altered characteristics and function of these cells. HSCs from these animals are hyperproliferative and have altered cell cycle. In addition, aging AhR-KO mice show characteristics consistent with premature bone marrow senescence and are prone to hematopoietic disease. Finally, some data suggest that the expression of the Ahr gene is regulated under conditions that control HSC proliferation. The presence of a normal functioning AhR may provide an important advantage to organisms by regulating the balance between quiescence and proliferation and preventing the premature exhaustion of HSCs and sensitivity to genetic alterations. This function assists in the preservation of HSC function and long-term multi-lineage generation over the lifespan of the organism. This also implicates a role for the AhR in the aging process. Furthermore, these functions may affect the sensitivity of HSCs to certain xenobiotics, including benzene. Defining the molecular mechanisms by which these events occur may lead to the identification of previously undefined roles of this transcription factor in human diseases, particularly those caused or affected by xenobiotics.
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Affiliation(s)
- Thomas A Gasiewicz
- Department of Environmental Medicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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25
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Soshilov A, Denison MS. Role of the Per/Arnt/Sim domains in ligand-dependent transformation of the aryl hydrocarbon receptor. J Biol Chem 2008; 283:32995-3005. [PMID: 18806268 PMCID: PMC2583286 DOI: 10.1074/jbc.m802414200] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 08/21/2008] [Indexed: 11/06/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR) mediates the toxic and biological effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and related compounds. In a process termed transformation, ligand binding converts the AhR into its high affinity DNA binding form that represents a dimer of the AhR and Arnt, a closely related nuclear protein. During transformation, protein chaperone Hsp90 is thought to be replaced by Arnt in overlapping binding sites in the basic helix loop helix and PASB domains of the AhR. Here, analysis of AhR variants containing a modified PASB domain and AhR PASA-PASB fragments of various lengths revealed (i) an inhibitory effect on transformation concomitant with Hsp90 binding in the PASB domain, (ii) an ability of the PASA-PASB fragment of the AhR to reproduce key steps in the transformation process, and (iii) a ligand-dependent conformational change in the PASA domain consistent with increased PASA exposure during AhR transformation. Based on these results, we propose a new mechanism of AhR transformation through initiation of Arnt dimerization and Hsp90 displacement in AhR PASA/B domains. This study provides insights into mechanisms of AhR transformation, dimerization of PAS domain proteins, and Hsp90 dissociation in activation of its client proteins.
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Affiliation(s)
- Anatoly Soshilov
- Department of Environmental Toxicology, University of California, Davis, California 95616, USA
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26
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Henry EC, Gasiewicz TA. Molecular determinants of species-specific agonist and antagonist activity of a substituted flavone towards the aryl hydrocarbon receptor. Arch Biochem Biophys 2008; 472:77-88. [PMID: 18294953 DOI: 10.1016/j.abb.2008.02.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Revised: 02/05/2008] [Accepted: 02/06/2008] [Indexed: 11/30/2022]
Abstract
The aryl hydrocarbon receptor (AhR) mediates the toxicity of dioxins and related xenobiotics. Other chemicals also bind the AhR to elicit either agonist or antagonist responses. Here we used site-directed mutagenesis within the ligand binding domain of murine AhR to probe for specific residues that might interact differentially with the antagonist 3'-methoxy-4'-nitroflavone (MNF) compared with the prototypical agonist TCDD. Reduced (3)H-TCDD binding, dioxin-response element (DRE) binding, and transcriptional activity were observed for several point mutants. One mutation, R355I, changed the response to MNF from antagonist to agonist. Notably, Ile is the residue found in the guinea pig AhR, towards which MNF has partial agonist activity in contrast to its strong antagonist activity in mouse. A similar reversal of response to MNF was observed in chimeric AhRs in which the C-terminal region of mAhR was replaced with the guinea pig C-terminal region. These data demonstrate that different amino acids can be important in binding of different AhR ligands and can mediate distinct responses. The ultimate response of the AhR also depends on how other portions of the receptor protein are functionally coupled to the initial ligand binding event.
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Affiliation(s)
- E C Henry
- Department of Environmental Medicine, University of Rochester Medical Center, 575 Elmwood Ave, Box EHSC, Rochester, NY 14642, USA.
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27
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McMillan BJ, Bradfield CA. The aryl hydrocarbon receptor sans xenobiotics: endogenous function in genetic model systems. Mol Pharmacol 2007; 72:487-98. [PMID: 17535977 DOI: 10.1124/mol.107.037259] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
For more than 30 years, the aryl hydrocarbon receptor [Ah receptor (AHR)] has been extensively scrutinized as the cellular receptor for numerous environmental contaminants, including polychlorinated dioxins, dibenzofurans, and biphenyls. Recent evidence argues that this description is incomplete and perhaps myopic. Ah receptor orthologs have been demonstrated to mediate diverse endogenous functions in our close vertebrate relatives as well as our distant invertebrate ancestors. Moreover, these endogenous functions suggest that xenobiotic toxicity may be best understood in the context of intrinsic AHR physiology. In this literature review, we survey the emerging picture of endogenous AHR biology from work in the vertebrate and invertebrate model systems Mus musculus, Caenorhabditis elegans, and Drosophila melanogaster.
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Affiliation(s)
- Brian J McMillan
- McArdle Laboratory for Cancer Research, University of Wisconsin Shool of Medicine and Public Health, Madison, Wisconsin, USA
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28
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Zatloukalová J, Svihálková-Sindlerová L, Kozubík A, Krcmár P, Machala M, Vondrácek J. β-Naphthoflavone and 3′-methoxy-4′-nitroflavone exert ambiguous effects on Ah receptor-dependent cell proliferation and gene expression in rat liver ‘stem-like’ cells. Biochem Pharmacol 2007; 73:1622-34. [PMID: 17324381 DOI: 10.1016/j.bcp.2007.01.032] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 01/24/2007] [Accepted: 01/24/2007] [Indexed: 10/23/2022]
Abstract
Both natural and synthetic flavonoids are known to interact with the aryl hydrocarbon receptor (AhR); however, their agonist/antagonist properties in vitro have been so far studied mostly in the context of cytochrome P450 1A1 gene (Cyp1a1) regulation. We investigated effects of two synthetic flavones known either as AhR agonist (beta-naphthoflavone; BNF) or antagonist (3'-methoxy-4'-nitroflavone; 3M4NF), using an in vitro model of liver 'stem-like' cells, on expression of various AhR target genes and AhR-dependent cell proliferation. We found that the presumed antagonist 3M4NF induces a partial nuclear translocation and activation of AhR. Although inhibiting the 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced Cyp1a1 expression, 3M4NF alone induced a minor increase of CYP1A1 mRNA and protein. However, 3M4NF did not induce AhR binding to synthetic dioxin response elements (DRE). In contrast to Cyp1a1, 3M4NF induced a marked expression of other AhR-regulated genes, such as Cyp1b1 and Nqo1, as well as transcriptional repression of Cdh13 gene, confirming that its effects may be promoter-context specific. Like BNF, 3M4NF induced AhR-dependent cell proliferation of contact-inhibited rat liver 'stem-like' WB-F344 cells, associated with a marked upregulation of Cyclin A, as well as the downregulation of proteins involved in formation of cell-cell contacts. Based on these experimental findings, we conclude that partial agonists/antagonists of AhR can increase cell proliferation rate and AhR-dependent genes expression in both cell type- and gene-specific manner. The specificity of effects of flavones on diverse AhR targets should be taken into account, when studying AhR signaling using presumed AhR antagonists.
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Affiliation(s)
- Jirina Zatloukalová
- Laboratory of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Czech Republic
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Pandini A, Denison MS, Song Y, Soshilov AA, Bonati L. Structural and functional characterization of the aryl hydrocarbon receptor ligand binding domain by homology modeling and mutational analysis. Biochemistry 2007; 46:696-708. [PMID: 17223691 PMCID: PMC2860805 DOI: 10.1021/bi061460t] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that is activated by a structurally diverse array of synthetic and natural chemicals, including toxic halogenated aromatic hydrocarbons such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Analysis of the molecular events occurring in the AhR ligand binding and activation processes requires structural information on the AhR Per-Arnt-Sim (PAS) B-containing ligand binding domain, for which no experimentally determined structure has been reported. With the availability of extensive structural information on homologous PAS-containing proteins, a reliable model of the mouse AhR PAS B domain was developed by comparative modeling techniques. The PAS domain structures of the functionally related hypoxia-inducible factor 2alpha (HIF-2alpha) and AhR nuclear translocator (ARNT) proteins, which exhibit the highest degree of sequence identity and similarity with AhR, were chosen to develop a two-template model. To confirm the features of the modeled domain, the effects of point mutations in selected residue positions on both TCDD binding to the AhR and TCDD-dependent transformation and DNA binding were analyzed. Mutagenesis and functional analysis results are consistent with the proposed model and confirm that the cavity modeled in the interior of the domain is indeed involved in ligand binding. Moreover, the physicochemical characteristics of some residues and of their mutants, along with the effects of mutagenesis on TCDD and DNA binding, also suggest some key features that are required for ligand binding and activation of mAhR at a molecular level, thus providing a framework for further studies.
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Affiliation(s)
- Alessandro Pandini
- Dipartimento di Scienze dell’Ambiente e del Territorio, Università degli Studi di Milano-Bicocca, Piazza della Scienza, 1, 20126 Milano, Italy
| | - Michael S. Denison
- Department of Environmental Toxicology, Meyer Hall, University of California, Davis, California 95616
| | - Yujuan Song
- Department of Environmental Toxicology, Meyer Hall, University of California, Davis, California 95616
| | - Anatoly A. Soshilov
- Department of Environmental Toxicology, Meyer Hall, University of California, Davis, California 95616
| | - Laura Bonati
- Dipartimento di Scienze dell’Ambiente e del Territorio, Università degli Studi di Milano-Bicocca, Piazza della Scienza, 1, 20126 Milano, Italy
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Frericks M, Temchura VV, Majora M, Stutte S, Esser C. Transcriptional signatures of immune cells in aryl hydrocarbon receptor (AHR)-proficient and AHR-deficient mice. Biol Chem 2006; 387:1219-26. [PMID: 16972790 DOI: 10.1515/bc.2006.151] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The ligand-activated aryl hydrocarbon receptor (AHR) is known to modulate many genes in a highly cell-specific manner, either directly or indirectly via secondary effects. In contrast, little is known about the effects of AHR deficiency on gene expression balance. We compared the transcriptome of CD4 T cells from AHR-/- mice and wild-type mice; 390 genes, many of them immunotypic, were deregulated in AHR-deficient CD4 cells. TCDD-induced transcriptome changes correlated with the AHR expression level in immune cells. However, there was little overlap in AHR-dependent transcripts found in T lineage cells or dendritic cells. Our results demonstrate flexible gene accessibility for the AHR in immune cells. The idea of a universal battery of AHR-responsive genes is not tenable.
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Affiliation(s)
- Markus Frericks
- Institut für Umweltmedizinische Forschung (IUF) at the Heinrich-Heine University of Düsseldorf, Auf'm Hennekamp 50, D-40225 Düsseldorf, Germany
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Zhao B, Baston DS, Hammock B, Denison MS. Interaction of diuron and related substituted phenylureas with the Ah receptor pathway. J Biochem Mol Toxicol 2006; 20:103-13. [PMID: 16788953 PMCID: PMC3032054 DOI: 10.1002/jbt.20126] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that mediates many of the biological and toxicological actions of structurally diverse chemicals, including the ubiquitous environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin. Here, we have examined the ability of diuron, a widely used herbicide, and several structurally related substituted phenylureas to bind to and activate/inhibit the AhR and AhR signal transduction. Diuron induced CYP1A1 mRNA levels in mouse hepatoma (Hepa1c1c7) cells and AhR-dependent luciferase reporter gene expression in stably transfected mouse, rat, guinea pig, and human cell lines. In addition, ligand binding and gel retardation analysis demonstrated the ability of diuron to competitively bind to and stimulate AhR transformation and DNA binding in vitro and in intact cells. Several structurally related substituted phenylureas competitively bound to the guinea pig hepatic cytosolic AhR, inhibited 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced AhR-dependent luciferase reporter gene expression in a species-specific manner and stimulated AhR transformation and DNA binding, consistent with their role as partial AhR agonists. These results demonstrate not only that diuron and related substituted phenylureas are AhR ligands but also that exposure to these chemicals could induce/inhibit AhR-dependent biological effects.
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Affiliation(s)
- Bin Zhao
- Department of Environmental Toxicology, University of California, Davis, CA 95616-8588, USA
| | - David S. Baston
- Department of Environmental Toxicology, University of California, Davis, CA 95616-8588, USA
| | - Bruce Hammock
- Department of Entomology, University of California, Davis, CA, USA
- University of California Davis Cancer Center, Sacramento, CA, USA
| | - Michael S. Denison
- Department of Environmental Toxicology, University of California, Davis, CA 95616-8588, USA
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Bussmann UA, Bussmann LE, Barañao JL. An aryl hydrocarbon receptor agonist amplifies the mitogenic actions of estradiol in granulosa cells: evidence of involvement of the cognate receptors. Biol Reprod 2005; 74:417-26. [PMID: 16237154 DOI: 10.1095/biolreprod.105.043901] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that, besides mediating toxic responses, may have a central role in ovarian physiology. Studying the actions of AHR ligands on granulosa cells function, we have found that beta-naphthoflavone amplifies the comitogenic actions of FSH and 17beta-estradiol in a dose-dependent manner. This amplification was even greater in cells that overexpress the AHR and was reversed by cotreatment with the AHR antagonist alpha-naphthoflavone, suggesting that this effect is mediated by the AHR. The estrogen receptor is likewise implicated in this phenomenon, because a pure antiestrogen abolished the described synergism. However, the more traditional inhibitory AHR-estrogen receptor interaction was observed on the estrogen response element-driven transcriptional activity. On the other hand, alpha-naphthoflavone inhibited dose-dependently the mitogenic actions of FSH and 17beta-estradiol. Beta-naphthoflavone induced the expression of Cyp1a1 and Cyp1b1 transcripts, two well-characterized AHR-inducible genes that code for hydroxylases that metabolize estradiol to catecholestrogens. Nevertheless, the positive effect of beta-naphthoflavone on proliferation was not caused by increased metabolism of estradiol to catecholestrogens, because these compounds inhibited the hormonally stimulated DNA synthesis. This latter inhibition exerted by catecholestrogens suggests that these hydroxylases would play a regulatory point in granulosa cell proliferation. Our study indicates that AHR ligands modulate the proliferation of rat granulosa cells, and demonstrates for the first time that an agonist of this receptor is able to amplify the comitogenic action of classical hormones through a mechanism that might implicate a positive cross-talk between the AHR and the estrogen receptor pathways.
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Affiliation(s)
- Ursula A Bussmann
- Instituto de Biologia y Medicina Experimental-CONICET, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina
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Wang WD, Wang Y, Wen HJ, Buhler DR, Hu CH. Phenylthiourea as a weak activator of aryl hydrocarbon receptor inhibiting 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced CYP1A1 transcription in zebrafish embryo. Biochem Pharmacol 2004; 68:63-71. [PMID: 15183118 DOI: 10.1016/j.bcp.2004.03.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2003] [Accepted: 03/19/2004] [Indexed: 11/21/2022]
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor that can be activated by a diverse synthetic and naturally-occurring chemicals, such as the halogenated aromatic hydrocarbons (HAHs) and the non-halogenated polycyclic aromatic hydrocarbons (PAHs). The liganded AHR modulates the genetic activity of a variety of xenobiotic-responsive genes, including cytochrome P4501A1 (CYP1A1). The tyrosinase inhibitor 1-phenyl-2-thiourea (PTU) is widely used in zebrafish research to suppress pigmentation in developing embryos/fry. Here we showed that 0.2 mM PTU induced a basal level of CYP1A1 transcription in zebrafish embryonic integument as early as 24 h postfertilization (hpf) stage. Subsequently, PTU induced CYP1A1 transcription in blood vessels at 36 hpf. During larval stage, the liver and all pharyngeal arch vessels of PTU-treated embryos exhibited CYP1A1 transcription as well. Comparing to TCDD, PTU induces CYP1A1 transcription with much lower efficacy in zebrafish embryos. Coincubating the embryos with PTU and TCDD led to repressing TCDD-induced CYP1A1 transcription. Mechanistic studies indicated that both of PTU- and TCDD-mediated CYP1A1 transcriptions are modulated by the same AHR-ARNT signaling pathway.
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Affiliation(s)
- Wen-Der Wang
- Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung 202-24, Taiwan, ROC
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Zhou J, Gasiewicz TA. 3'-methoxy-4'-nitroflavone, a reported aryl hydrocarbon receptor antagonist, enhances Cyp1a1 transcription by a dioxin responsive element-dependent mechanism. Arch Biochem Biophys 2003; 416:68-80. [PMID: 12859983 DOI: 10.1016/s0003-9861(03)00274-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor, regulating expression of a group of specific genes including cytochrome P450 1A1 (Cyp1a1). Stably transfected luciferase with dioxin responsive elements (DRE) in its promoter region has been commonly used as a reporter gene to study the mechanism of AhR signaling and compare potencies of TCDD and related compounds. However, how these two genes might respond to structurally diverse AhR ligands was unknown. This study investigates their expression in the same cells in response to TCDD, the most potent agonist, and 3'M4'NF, a reported potent antagonist. Our data suggest that these two compounds appear to play different roles in regulating these genes. While TCDD enhanced transcription of both genes, 3'M4'NF induced the endogenous Cyp1a1, but not the reporter gene. Mechanistic studies indicated that the increase in induction of CYP1A1 protein by 3'M4'NF was mediated by AhR-dependent transcriptional activation. Further analysis of the Cyp1a1 promoter sequence did not reveal any 3'M4'NF-specific responsive elements other than DREs. Rather, the interaction between the 3'M4'NF-bound receptor complex and DREs was confirmed by the observation that a single nucleotide mutation in DRE core sequences obliterated AhR enhancer activity in response to both TCDD and 3'M4'NF. Together these data suggest that 3'M4'NF, a weak AhR agonist, activates the AhR to recognize and interact with the same DREs as TCDD. However, depending on its concentration as well as the promoter context of a particular gene, the ability of 3'M4'NF to act as an AhR antagonist or agonist may appear different for various genes.
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Affiliation(s)
- Junguo Zhou
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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