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Sondermann NC, Faßbender S, Hartung F, Hätälä AM, Rolfes KM, Vogel CFA, Haarmann-Stemmann T. Functions of the aryl hydrocarbon receptor (AHR) beyond the canonical AHR/ARNT signaling pathway. Biochem Pharmacol 2023; 208:115371. [PMID: 36528068 PMCID: PMC9884176 DOI: 10.1016/j.bcp.2022.115371] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022]
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor regulating adaptive and maladaptive responses toward exogenous and endogenous signals. Research from various biomedical disciplines has provided compelling evidence that the AHR is critically involved in the pathogenesis of a variety of diseases and disorders, including autoimmunity, inflammatory diseases, endocrine disruption, premature aging and cancer. Accordingly, AHR is considered an attractive target for the development of novel preventive and therapeutic measures. However, the ligand-based targeting of AHR is considerably complicated by the fact that the receptor does not always follow the beaten track, i.e. the canonical AHR/ARNT signaling pathway. Instead, AHR might team up with other transcription factors and signaling molecules to shape gene expression patterns and associated physiological or pathophysiological functions in a ligand-, cell- and micromilieu-dependent manner. Herein, we provide an overview about some of the most important non-canonical functions of AHR, including crosstalk with major signaling pathways involved in controlling cell fate and function, immune responses, adaptation to low oxygen levels and oxidative stress, ubiquitination and proteasomal degradation. Further research on these diverse and exciting yet often ambivalent facets of AHR biology is urgently needed in order to exploit the full potential of AHR modulation for disease prevention and treatment.
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Affiliation(s)
- Natalie C Sondermann
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Sonja Faßbender
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Frederick Hartung
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Anna M Hätälä
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Katharina M Rolfes
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Christoph F A Vogel
- Department of Environmental Toxicology and Center for Health and the Environment, University of California, Davis, CA 95616, USA
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The Aryl Hydrocarbon Receptor (AHR): A Novel Therapeutic Target for Pulmonary Diseases? Int J Mol Sci 2022; 23:ijms23031516. [PMID: 35163440 PMCID: PMC8836075 DOI: 10.3390/ijms23031516] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 12/30/2021] [Accepted: 01/13/2022] [Indexed: 01/08/2023] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a cytoplasmic transcription factor that is well-known for regulating xenobiotic metabolism. Studies in knockout and transgenic mice indicate that the AHR plays a vital role in the development of liver and regulation of reproductive, cardiovascular, hematopoietic, and immune homeostasis. In this focused review on lung diseases associated with acute injury and alveolar development, we reviewed and summarized the current literature on the mechanistic role(s) and therapeutic potential of the AHR in acute lung injury, chronic obstructive pulmonary disease, and bronchopulmonary dysplasia (BPD). Pre-clinical studies indicate that endogenous AHR activation is necessary to protect neonatal and adult lungs against hyperoxia- and cigarette smoke-induced injury. Our goal is to provide insight into the high translational potential of the AHR in the meaningful management of infants and adults with these lung disorders that lack curative therapies.
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Park JF, Clark VR, Banerjee S, Hong J, Razee A, Williams T, Fishbein G, Saddic L, Umar S. Transcriptomic Analysis of Right Ventricular Remodeling in Two Rat Models of Pulmonary Hypertension: Identification and Validation of Epithelial-to-Mesenchymal Transition in Human Right Ventricular Failure. Circ Heart Fail 2021; 14:e007058. [PMID: 33541093 DOI: 10.1161/circheartfailure.120.007058] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Right ventricular (RV) dysfunction is a significant prognostic determinant of morbidity and mortality in pulmonary arterial hypertension (PAH). Despite the importance of RV function in PAH, the underlying molecular mechanisms of RV dysfunction secondary to PAH remain unclear. We aim to identify and compare molecular determinants of RV failure using RNA sequencing of RV tissue from 2 clinically relevant animal models of PAH. METHODS We performed RNA sequencing on RV from rats treated with monocrotaline or Sugen with hypoxia/normoxia. PAH and RV failure were confirmed by catheterization and echocardiography. We validated the RV transcriptome results using quantitative real-time polymerase chain reaction, immunofluorescence, and Western blot. Immunohistochemistry and immunofluorescence were performed on human RV tissue from control (n=3) and PAH-induced RV failure patients (n=5). RESULTS We identified similar transcriptomic profiles of RV from monocrotaline- and Sugen with hypoxia-induced RV failure. Pathway analysis showed genes enriched in epithelial-to-mesenchymal transition, inflammation, and metabolism. Histological staining of human RV tissue from patients with RV failure secondary to PAH revealed significant RV fibrosis and endothelial-to-mesenchymal transition, as well as elevated cellular communication network factor 2 (top gene implicated in epithelial-to-mesenchymal transition/endothelial-to-mesenchymal transition) expression in perivascular areas compared with normal RV. CONCLUSIONS Transcriptomic signature of RV failure in monocrotaline and Sugen with hypoxia models showed similar gene expressions and biological pathways. We provide translational relevance of this transcriptomic signature using RV from patients with PAH to demonstrate evidence of epithelial-to-mesenchymal transition/endothelial-to-mesenchymal transition and protein expression of cellular communication network factor 2 (CTGF [connective tissue growth factor]). Targeting specific molecular mechanisms responsible for RV failure in monocrotaline and Sugen with hypoxia models may identify novel therapeutic strategies for PAH-associated RV failure.
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Affiliation(s)
- John F Park
- Division of Molecular Medicine, Department of Anesthesiology and Perioperative Medicine (J.F.P., V.R.C., S.B., J.H., A.R., T.W., L.S., S.U.), David Geffen School of Medicine, UCLA, Los Angeles, CA
| | - Varina R Clark
- Division of Molecular Medicine, Department of Anesthesiology and Perioperative Medicine (J.F.P., V.R.C., S.B., J.H., A.R., T.W., L.S., S.U.), David Geffen School of Medicine, UCLA, Los Angeles, CA
| | - Somanshu Banerjee
- Division of Molecular Medicine, Department of Anesthesiology and Perioperative Medicine (J.F.P., V.R.C., S.B., J.H., A.R., T.W., L.S., S.U.), David Geffen School of Medicine, UCLA, Los Angeles, CA
| | - Jason Hong
- Division of Molecular Medicine, Department of Anesthesiology and Perioperative Medicine (J.F.P., V.R.C., S.B., J.H., A.R., T.W., L.S., S.U.), David Geffen School of Medicine, UCLA, Los Angeles, CA
- Division of Pulmonary Critical Care Medicine, Department of Medicine, UCLA, Los Angeles, CA (J.H.)
| | - Asif Razee
- Division of Molecular Medicine, Department of Anesthesiology and Perioperative Medicine (J.F.P., V.R.C., S.B., J.H., A.R., T.W., L.S., S.U.), David Geffen School of Medicine, UCLA, Los Angeles, CA
| | - Tiffany Williams
- Division of Molecular Medicine, Department of Anesthesiology and Perioperative Medicine (J.F.P., V.R.C., S.B., J.H., A.R., T.W., L.S., S.U.), David Geffen School of Medicine, UCLA, Los Angeles, CA
| | - Gregory Fishbein
- Department of Pathology (G.F.), David Geffen School of Medicine, UCLA, Los Angeles, CA
| | - Lou Saddic
- Division of Molecular Medicine, Department of Anesthesiology and Perioperative Medicine (J.F.P., V.R.C., S.B., J.H., A.R., T.W., L.S., S.U.), David Geffen School of Medicine, UCLA, Los Angeles, CA
| | - Soban Umar
- Division of Molecular Medicine, Department of Anesthesiology and Perioperative Medicine (J.F.P., V.R.C., S.B., J.H., A.R., T.W., L.S., S.U.), David Geffen School of Medicine, UCLA, Los Angeles, CA
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Zhu X, Sun Q, Tan WS, Cai H. Reducing TGF-β1 cooperated with StemRegenin 1 promoted the expansion ex vivo of cord blood CD34 + cells by inhibiting AhR signalling. Cell Prolif 2021; 54:e12999. [PMID: 33522060 PMCID: PMC7941221 DOI: 10.1111/cpr.12999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 12/13/2020] [Accepted: 01/12/2021] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE As an inhibitor of the AhR signalling pathway, StemRegenin 1 (SR1) not only promotes the expansion of CD34+ cells but also increases CD34- cell numbers. These CD34- cells influenced the ex vivo expansion of CD34+ cells. In this work, the effects of periodically removing CD34- cells combined with SR1 addition on the ex vivo expansion and biological functions of HSCs were investigated. MATERIALS AND METHODS CD34- cells were removed periodically with SR1 addition to investigate cell subpopulations, cell expansion, biological functions, expanded cell division mode and supernatant TGF-β1 contents. RESULTS After 10-day culture, the expansion of CD34+ cells in the CD34- cell removal plus SR1 group was significantly higher than that in the control group and the SR1 group. Moreover, periodically removing CD34- cells with SR1 addition improved the biological function of expanded CD34+ cells and significantly increased the percentage of self-renewal symmetric division of CD34+ cells. In addition, the concentration of total TGF-β1 and activated TGF-β1 in the supernatant was significantly lower than those in the control group and the SR1 group. RT-qPCR results showed that the periodic removal of CD34- cells with cooperation from SR1 further reduced the expression of AhR-related genes. CONCLUSIONS Periodic removal of CD34- cells plus cooperation with SR1 improved the expansion of CD34+ cells, maintained better biological function of expanded CD34+ cells and reduced the TGF-β1 contents by downregulating AhR signalling.
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Affiliation(s)
- Xuejun Zhu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Qihao Sun
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Wen-Song Tan
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Haibo Cai
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
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Serna E, Cespedes C, Vina J. Anti-Aging Physiological Roles of Aryl Hydrocarbon Receptor and Its Dietary Regulators. Int J Mol Sci 2020; 22:ijms22010374. [PMID: 33396477 PMCID: PMC7795126 DOI: 10.3390/ijms22010374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/18/2020] [Accepted: 12/26/2020] [Indexed: 01/13/2023] Open
Abstract
The vast majority of the literature on the aryl hydrocarbon receptor is concerned with its functions in xenobiotic detoxification. However, in the course of evolution, this receptor had to have physiological (rather than toxicological) functions. Our aim was to review the aryl hydrocarbon receptor’s role in the physiological functions involved in aging. This study was performed by searching the MEDLINE and Google Academic databases. A total of 34 articles were selected that focused specifically on the aryl hydrocarbon receptor and aging, the aryl hydrocarbon receptor and physiological functions, and the combination of both. This receptor’s main physiological functions (mediated by the modulation of gene expression) were cell regeneration, the immune reaction, intestinal homeostasis, and cell proliferation. Furthermore, it was shown that the loss of this receptor led to premature aging. This process may be caused by the dysregulation of hematopoietic stem cells, loss of glucose and lipid homeostasis, increase in inflammation, and deterioration of the brain. We conclude that the aryl hydrocarbon receptor, apart from its well-established role in xenobiotic detoxication, plays an important role in physiological functions and in the aging process. Modulation of the signaling pathway of this receptor could be a therapeutic target of interest in aging.
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Affiliation(s)
- Eva Serna
- Correspondence: ; Tel.: +34-96-386-41-00 (ext. 83171)
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An introduction to EpiPol (Epigenetic affecting Polymorphism) concept with an in silico identification of CpG-affecting SNPs in the upstream regulatory sequences of human AHR gene. Meta Gene 2020. [DOI: 10.1016/j.mgene.2020.100805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Garland MA, Reynolds K, Zhou CJ. Environmental mechanisms of orofacial clefts. Birth Defects Res 2020; 112:1660-1698. [PMID: 33125192 PMCID: PMC7902093 DOI: 10.1002/bdr2.1830] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 10/07/2020] [Accepted: 10/13/2020] [Indexed: 12/11/2022]
Abstract
Orofacial clefts (OFCs) are among the most common birth defects and impart a significant burden on afflicted individuals and their families. It is increasingly understood that many nonsyndromic OFCs are a consequence of extrinsic factors, genetic susceptibilities, and interactions of the two. Therefore, understanding the environmental mechanisms of OFCs is important in the prevention of future cases. This review examines the molecular mechanisms associated with environmental factors that either protect against or increase the risk of OFCs. We focus on essential metabolic pathways, environmental signaling mechanisms, detoxification pathways, behavioral risk factors, and biological hazards that may disrupt orofacial development.
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Affiliation(s)
- Michael A. Garland
- Department of Biochemistry and Molecular Medicine, University of California at Davis, School of Medicine, Sacramento, CA 95817
- Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis, School of Medicine, Sacramento, CA 95817
| | - Kurt Reynolds
- Department of Biochemistry and Molecular Medicine, University of California at Davis, School of Medicine, Sacramento, CA 95817
- Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis, School of Medicine, Sacramento, CA 95817
- Biochemistry, Molecular, Cellular, and Developmental Biology (BMCDB) graduate group, University of California, Davis, CA 95616
| | - Chengji J. Zhou
- Department of Biochemistry and Molecular Medicine, University of California at Davis, School of Medicine, Sacramento, CA 95817
- Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis, School of Medicine, Sacramento, CA 95817
- Biochemistry, Molecular, Cellular, and Developmental Biology (BMCDB) graduate group, University of California, Davis, CA 95616
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Sarin H. Pressure regulated basis for gene transcription by delta-cell micro-compliance modeled in silico: Biphenyl, bisphenol and small molecule ligand models of cell contraction-expansion. PLoS One 2020; 15:e0236446. [PMID: 33021979 PMCID: PMC7537880 DOI: 10.1371/journal.pone.0236446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/06/2020] [Indexed: 12/19/2022] Open
Abstract
Molecular diameter, lipophilicity and hydrophilicity exclusion affinity limits exist for small molecule carrier-mediated diffusion or transport through channel pores or interaction with the cell surface glycocalyx. The molecular structure lipophilicity limit for non-specific carrier-mediated transmembrane diffusion through polarity-selective transport channels of the cell membrane is Lexternal structure ∙ Hpolar group-1 of ≥ 1.07. The cell membrane channel pore size is > 0.752 and < 0.758 nm based on a 3-D ellipsoid model (biphenyl), and within the molecular diameter size range 0.744 and 0.762 nm based on a 2-D elliptical model (alkanol). The adjusted van der Waals diameter (vdWD, adj; nm) for the subset of halogenated vapors is predictive of the required MAC for anesthetic potency at an initial (-) Δ Cmicro effect. The molecular structure L ∙ Hpolar group-1 for Neu5Ac is 0.080, and the L ∙ Hpolar group-1 interval range for the cell surface glycocalyx hydrophilicity barrier interaction is 0.101 (Saxitoxin, Stx; Linternal structure ∙ Hpolar group-1) - 0.092 (m-xylenediamine, Lexternal structure · Hpolar group). Differential predictive effective pressure mapping of gene activation or repression reveals that p-dioxin exposure results in activation of AhR-Erβ (Arnt)/Nrf-2, Pparδ, Errγ (LxRα), Dio3 (Dio2) and Trα limbs, and due to high affinity Dio2 and Dio3 (OH-TriCDD, Lext · H-1: 1.91–4.31) exothermy-antagonism (Δ contraction) with high affinity T4/rT3-TRα-mediated agonism (Δ expansion). co-planar PCB metabolite exposure (Lext · H-1: 1.95–3.91) results in activation of AhR (Erα/β)/Nrf2, Rev-Erbβ, Errα, Dio3 (Dio2) and Trα limbs with a Δ Cmicro contraction of 0.89 and Δ Cmicro expansion of 1.05 as compared to p-dioxin. co-, ortho-planar PCB metabolite exposure results in activation of Car/PxR, Pparα (Srebf1,—Lxrβ), Arnt (AhR-Erβ), AR, Dio1 (Dio2) and Trβ limbs with a Δ Cmicro contraction of 0.73 and Δ Cmicro expansion of 1.18 (as compared to p-dioxin). Bisphenol A exposure (Lext struct ∙ H-1: 1.08–1.12, BPA–BPE, Errγ; BPAF, Lext struct ∙ H-1: 1.23, CM Erα, β) results in increased duration at Peff for Timm8b (Peff 0.247) transcription and in indirect activation of the AhR/Nrf-2 hybrid pathway with decreased duration at Peff 0.200 (Nrf1) and increased duration at Peff 0.257 (Dffa). The Bpa/Bpaf convergent pathway Cmicro contraction-expansion response increase in the lower Peff interval is 0.040; in comparison, small molecule hormone Δ Cmicro contraction-expansion response increases in the lower Peff intervals for gene expression ≤ 0.168 (Dex· GR) ≥ 0.156 (Dht · AR), with grade of duration at Peff (min·count) of 1.33x105 (Dex/Cort) and 1.8–2.53x105 (Dht/R1881) as compared to the (-) coupled (+) Δ CmicroPeff to 0.136 (Wnt5a, Esr2) with applied DES (1.86x106). The subtype of trans-differentiated cell as a result of an applied toxin or toxicant is predictable by delta-Cmicro determined by Peff mapping. Study findings offer additional perspective on the basis for pressure regulated gene transcription by alterations in cell micro-compliance (Δ contraction-expansion, Cmicro), and are applicable for the further predictive modeling of gene to gene transcription interactions, and small molecule modulation of cell effective pressure (Peff) and its potential.
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Affiliation(s)
- Hemant Sarin
- Freelance Investigator in Translational Science and Medicine, Charleston, West Virginia, United States of America
- * E-mail:
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Shi Y, Zeng Z, Yu J, Tang B, Tang R, Xiao R. The aryl hydrocarbon receptor: An environmental effector in the pathogenesis of fibrosis. Pharmacol Res 2020; 160:105180. [PMID: 32877693 DOI: 10.1016/j.phrs.2020.105180] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 12/16/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a highly conserved transcription factor that can be activated by small molecules provided by dietary, plant, or microbial metabolites, and environmental pollutants. AhR is expressed in many cell types and engages in crosstalk with other signaling pathways, and therefore provides a molecular pathway that integrates environmental cues and metabolic processes. Fibrosis, which is defined as an aberrant extracellular matrix formation, is a reparative process in the terminal stage of chronic diseases. Both environmental and internal factors have been shown to participate in the pathogenesis of fibrosis; however, the underlying mechanisms still remain elusive. In this review, the potential role of AhR in the process of fibrosis, as well as potential opportunities and challenges in the development of AhR targeting therapeutics, are summarized.
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Affiliation(s)
- Yaqian Shi
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China; Hunan Key Laboratory of Medical Epigenetics, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Zhuotong Zeng
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China; Hunan Key Laboratory of Medical Epigenetics, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Jiangfan Yu
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China; Hunan Key Laboratory of Medical Epigenetics, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Bingsi Tang
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China; Hunan Key Laboratory of Medical Epigenetics, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Rui Tang
- Department of Rheumatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Rong Xiao
- Department of Dermatology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China; Hunan Key Laboratory of Medical Epigenetics, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China.
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Nakano N, Sakata N, Katsu Y, Nochise D, Sato E, Takahashi Y, Yamaguchi S, Haga Y, Ikeno S, Motizuki M, Sano K, Yamasaki K, Miyazawa K, Itoh S. Dissociation of the AhR/ARNT complex by TGF-β/Smad signaling represses CYP1A1 gene expression and inhibits benze[a]pyrene-mediated cytotoxicity. J Biol Chem 2020; 295:9033-9051. [PMID: 32409577 PMCID: PMC7335805 DOI: 10.1074/jbc.ra120.013596] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/11/2020] [Indexed: 12/22/2022] Open
Abstract
Cytochrome P450 1A1 (CYP1A1) catalyzes the metabolic activation of polycyclic aromatic hydrocarbons (PAHs) such as benzo[a]pyrene (B[a]P) and is transcriptionally regulated by the aryl hydrocarbon receptor (AhR)/AhR nuclear translocator (ARNT) complex upon exposure to PAHs. Accordingly, inhibition of CYP1A1 expression reduces production of carcinogens from PAHs. Although transcription of the CYP1A1 gene is known to be repressed by transforming growth factor-β (TGF-β), how TGF-β signaling is involved in the suppression of CYP1A1 gene expression has yet to be clarified. In this study, using mammalian cell lines, along with shRNA-mediated gene silencing, CRISPR/Cas9-based genome editing, and reporter gene and quantitative RT-PCR assays, we found that TGF-β signaling dissociates the B[a]P-mediated AhR/ARNT heteromeric complex. Among the examined Smads, Smad family member 3 (Smad3) strongly interacted with both AhR and ARNT via its MH2 domain. Moreover, hypoxia-inducible factor 1α (HIF-1α), which is stabilized upon TGF-β stimulation, also inhibited AhR/ARNT complex formation in the presence of B[a]P. Thus, TGF-β signaling negatively regulated the transcription of the CYP1A1 gene in at least two different ways. Of note, TGF-β abrogated DNA damage in B[a]P-exposed cells. We therefore conclude that TGF-β may protect cells against carcinogenesis because it inhibits CYP1A1-mediated metabolic activation of PAHs as part of its anti-tumorigenic activities.
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Affiliation(s)
- Naoko Nakano
- Laboratory of Biochemistry, Showa Pharmaceutical University, Tokyo, Japan
| | - Nobuo Sakata
- Laboratory of Biochemistry, Showa Pharmaceutical University, Tokyo, Japan
| | - Yuki Katsu
- Laboratory of Biochemistry, Showa Pharmaceutical University, Tokyo, Japan
| | - Daiki Nochise
- Laboratory of Biochemistry, Showa Pharmaceutical University, Tokyo, Japan
| | - Erika Sato
- Laboratory of Biochemistry, Showa Pharmaceutical University, Tokyo, Japan
| | - Yuta Takahashi
- Laboratory of Biochemistry, Showa Pharmaceutical University, Tokyo, Japan
| | - Saori Yamaguchi
- Laboratory of Biochemistry, Showa Pharmaceutical University, Tokyo, Japan
| | - Yoko Haga
- Laboratory of Biochemistry, Showa Pharmaceutical University, Tokyo, Japan
| | - Souichi Ikeno
- Laboratory of Biochemistry, Showa Pharmaceutical University, Tokyo, Japan
| | - Mitsuyoshi Motizuki
- Department of Biochemistry, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Keigo Sano
- Laboratory of Biochemistry, Showa Pharmaceutical University, Tokyo, Japan
| | - Kohei Yamasaki
- Laboratory of Biochemistry, Showa Pharmaceutical University, Tokyo, Japan
| | - Keiji Miyazawa
- Department of Biochemistry, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Susumu Itoh
- Laboratory of Biochemistry, Showa Pharmaceutical University, Tokyo, Japan.
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Mokhtar MM, Khidr EG, Shaban HM, Allam S, Elsadek BEM, Salama SA, Ali SS. The effect of aryl hydrocarbon receptor ligands on gentamicin-induced nephrotoxicity in rats. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:16189-16202. [PMID: 32112355 DOI: 10.1007/s11356-020-08073-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 02/11/2020] [Indexed: 06/10/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs)/aryl hydrocarbon receptor (AhR) regulate the expression of target genes, including drug transporter genes which harbor xenobiotic response element (XRE) in their promoter regions. Thus, PAHs/AhR could alter the toxicokinetic profile of many nephrotoxic drugs, including aminoglycosides. In the current study, we investigated the expression and localization of AhR and megalin in rat kidney. Furthermore, we investigated whether AhR and its ligands could modulate the expression of megalin and consequently the gentamicin-induced nephrotoxicity (GN) in rats. Both megalin and AhR receptors are expressed in the proximal tubules of the rat kidney. Treatment with AhR agonist benzo(a)pyrene aggravated GN as indicated by a significant increase in serum creatinine, BUN, KIM1, NAGL, CD-86, and urinary albumin/creatinine ratio. On the other hand, treatment with AhR antagonist resveratrol ameliorated GN as manifested by a pronounced decrease in the aforementioned parameters. The effects of AhR ligands on GN were associated with altered expression of megalin receptor.
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Affiliation(s)
- Mahmoud Mohamed Mokhtar
- Biochemistry Department-Faculty of Pharmacy (Boys), Al-Azhar University, Almokhayam Aldaem Street, 6th Province, Nasr City, Cairo, 13465, Egypt.
| | - Emad Gamil Khidr
- Biochemistry Department-Faculty of Pharmacy (Boys), Al-Azhar University, Almokhayam Aldaem Street, 6th Province, Nasr City, Cairo, 13465, Egypt
| | - Hesham Mohamed Shaban
- Biochemistry Department-Faculty of Pharmacy (Boys), Al-Azhar University, Almokhayam Aldaem Street, 6th Province, Nasr City, Cairo, 13465, Egypt
| | - Shady Allam
- Pharmacology and Toxicology Department-Faculty of Pharmacy, Kafrelsheikh University, Kafr El Sheikh, Egypt
| | - Bakheet E M Elsadek
- Biochemistry Department-Faculty of Pharmacy (Boys), Assuit Branch, Al-Azhar University, Assuit, Egypt
| | - Salama Abdou Salama
- Pharmacology and Toxicology Department-Faculty of Pharmacy (Boys), Al-Azhar University, Almokhayam Aldaem Street, 6th Province, Nasr City, Cairo, 13465, Egypt
| | - Shawkey Saddik Ali
- Biochemistry Department-Faculty of Pharmacy (Boys), Al-Azhar University, Almokhayam Aldaem Street, 6th Province, Nasr City, Cairo, 13465, Egypt
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Hammond CL, Roztocil E, Phipps RP, Feldon SE, Woeller CF. Proton pump inhibitors attenuate myofibroblast formation associated with thyroid eye disease through the aryl hydrocarbon receptor. PLoS One 2019; 14:e0222779. [PMID: 31536596 PMCID: PMC6752849 DOI: 10.1371/journal.pone.0222779] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 09/06/2019] [Indexed: 12/15/2022] Open
Abstract
Thyroid eye disease (TED) can lead to scar formation and tissue remodeling in the orbital space. In severe cases, the scarring process leads to sight-threatening pathophysiology. There is no known effective way to prevent scar formation in TED patients, or to reverse scarring once it occurs. In this study, we show that the proton pump inhibitors (PPIs), esomeprazole and lansoprazole, can prevent transforming growth factor beta (TGFβ)-mediated differentiation of TED orbital fibroblasts to myofibroblasts, a critical step in scar formation. Both PPIs prevent TGFβ-induced increases in alpha-smooth muscle actin (αSMA), calponin, and collagen production and reduce TED orbital fibroblast cell proliferation and migration. Esomeprazole and lansoprazole exert these effects through an aryl hydrocarbon receptor (AHR)-dependent pathway that includes reducing β-catenin/Wnt signaling. We conclude that PPIs are potentially useful therapies for preventing or treating TED by reducing the myofibroblast accumulation that occurs in the disease.
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Affiliation(s)
- Christine L. Hammond
- Flaum Eye Institute, School of Medicine and Dentistry, University of Rochester, Rochester, New York, United States of America
| | - Elisa Roztocil
- Flaum Eye Institute, School of Medicine and Dentistry, University of Rochester, Rochester, New York, United States of America
| | - Richard P. Phipps
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York, United States of America
| | - Steven E. Feldon
- Flaum Eye Institute, School of Medicine and Dentistry, University of Rochester, Rochester, New York, United States of America
| | - Collynn F. Woeller
- Flaum Eye Institute, School of Medicine and Dentistry, University of Rochester, Rochester, New York, United States of America
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York, United States of America
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13
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Miret NV, Pontillo CA, Zárate LV, Kleiman de Pisarev D, Cocca C, Randi AS. Impact of endocrine disruptor hexachlorobenzene on the mammary gland and breast cancer: The story thus far. ENVIRONMENTAL RESEARCH 2019; 173:330-341. [PMID: 30951959 DOI: 10.1016/j.envres.2019.03.054] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 02/19/2019] [Accepted: 03/21/2019] [Indexed: 06/09/2023]
Abstract
Breast cancer incidence is increasing globally and exposure to endocrine disruptors has gained importance as a potential risk factor. Hexachlorobenzene (HCB) was once used as a fungicide and, despite being banned, considerable amounts are still released into the environment. HCB acts as an endocrine disruptor in thyroid, uterus and mammary gland and was classified as possibly carcinogenic to human. This review provides a thorough analysis of results obtained in the last 15 years of research and evaluates data from assays in mammary gland and breast cancer in diverse animal models. We discuss the effects of environmentally relevant HCB concentrations on the normal mammary gland and different stages of carcinogenesis, and attempt to elucidate its mechanisms of action at molecular level. HCB weakly binds to the aryl hydrocarbon receptor (AhR), activating both membrane (c-Src) and nuclear pathways. Through c-Src stimulation, AhR signaling interacts with other membrane receptors including estrogen receptor-α, insulin-like growth factor-1 receptor, epidermal growth factor receptor and transforming growth factor beta 1 receptors. In this way, several pathways involved in mammary morphogenesis and breast cancer development are modified, inducing tumor progression. HCB thus stimulates epithelial cell proliferation, preneoplastic lesions and alterations in mammary gland development as well as neoplastic cell migration and invasion, metastasis and angiogenesis in breast cancer. In conclusion, our findings support the hypothesis that the presence and bioaccumulation of HCB in high-fat tissues and during highly sensitive time windows such as pregnancy, childhood and adolescence make exposure a risk factor for breast tumor development.
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Affiliation(s)
- Noelia V Miret
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Laboratorio de Efectos Biológicos de Contaminantes Ambientales, Paraguay 2155, 5to piso, CP1121, Buenos Aires, Argentina.
| | - Carolina A Pontillo
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Laboratorio de Efectos Biológicos de Contaminantes Ambientales, Paraguay 2155, 5to piso, CP1121, Buenos Aires, Argentina.
| | - Lorena V Zárate
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Laboratorio de Efectos Biológicos de Contaminantes Ambientales, Paraguay 2155, 5to piso, CP1121, Buenos Aires, Argentina.
| | - Diana Kleiman de Pisarev
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Laboratorio de Efectos Biológicos de Contaminantes Ambientales, Paraguay 2155, 5to piso, CP1121, Buenos Aires, Argentina.
| | - Claudia Cocca
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Laboratorio de Radioisótopos, Junín 954, subsuelo, CP1113, Buenos Aires, Argentina.
| | - Andrea S Randi
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Laboratorio de Efectos Biológicos de Contaminantes Ambientales, Paraguay 2155, 5to piso, CP1121, Buenos Aires, Argentina.
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14
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Zhang S. The role of transforming growth factor β in T helper 17 differentiation. Immunology 2018; 155:24-35. [PMID: 29682722 PMCID: PMC6099164 DOI: 10.1111/imm.12938] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 04/11/2018] [Accepted: 04/11/2018] [Indexed: 12/12/2022] Open
Abstract
T helper 17 (Th17) cells play critical roles in inflammatory and autoimmune diseases. The lineage-specific transcription factor RORγt is the key regulator for Th17 cell fate commitment. A substantial number of studies have established the importance of transforming growth factor β (TGF-β) -dependent pathways in inducing RORγt expression and Th17 differentiation. TGF-β superfamily members TGF-β1 , TGF-β3 or activin A, in concert with interleukin-6 or interleukin-21, differentiate naive T cells into Th17 cells. Alternatively, Th17 differentiation can occur through TGF-β-independent pathways. However, the mechanism of how TGF-β-dependent and TGF-β-independent pathways control Th17 differentiation remains controversial. This review focuses on the perplexing role of TGF-β in Th17 differentiation, depicts the requirement of TGF-β for Th17 development, and underscores the multiple mechanisms underlying TGF-β-promoted Th17 generation, pathogenicity and plasticity. With new insights and comprehension from recent findings, this review specifically tackles the involvement of the canonical TGF-β signalling components, SMAD2, SMAD3 and SMAD4, summarizes diverse SMAD-independent mechanisms, and highlights the importance of TGF-β signalling in balancing the reciprocal conversion of Th17 and regulatory T cells. Finally, this review includes discussions and perspectives and raises important mechanistic questions about the role of TGF-β in Th17 generation and function.
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Affiliation(s)
- Song Zhang
- State Key Laboratory of Medicinal Chemical BiologyCollege of Life SciencesNankai UniversityTianjinChina
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15
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McAleer JP, Fan J, Roar B, Primerano DA, Denvir J. Cytokine Regulation in Human CD4 T Cells by the Aryl Hydrocarbon Receptor and Gq-Coupled Receptors. Sci Rep 2018; 8:10954. [PMID: 30026493 PMCID: PMC6053392 DOI: 10.1038/s41598-018-29262-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 07/09/2018] [Indexed: 12/11/2022] Open
Abstract
Th17 cells contribute to host defense on mucosal surfaces but also provoke autoimmune diseases when directed against self-antigens. Identifying therapeutic targets that regulate Th17 cell differentiation and/or cytokine production has considerable value. Here, we study the aryl hydrocarbon receptor (AhR)-dependent transcriptome in human CD4 T cells treated with Th17-inducing cytokines. We show that the AhR reciprocally regulates IL-17 and IL-22 production in human CD4 T cells. Global gene expression analysis revealed that AhR ligation decreased IL21 expression, correlating with delayed upregulation of RORC during culture with Th17-inducing cytokines. Several of the AhR-dependent genes have known roles in cellular assembly, organization, development, growth and proliferation. We further show that expression of GPR15, GPR55 and GPR68 positively correlates with IL-22 production in the presence of the AhR agonist FICZ. Activation of GPR68 with the lorazepam derivative ogerin resulted in suppression of IL-22 and IL-10 secretion by T cells, with no effect on IL-17. Under neutral Th0 conditions, ogerin and the Gq/11 receptor inhibitor YM254890 blunted IL-22 induction by FICZ. These data reveal the AhR-dependent transcriptome in human CD4 T cells and suggest the mechanism through which the AhR regulates T cell function may be partially dependent on Gq-coupled receptors including GPR68.
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Affiliation(s)
- Jeremy P McAleer
- Department of Pharmaceutical Science and Research, Marshall University School of Pharmacy, Huntington, WV, 25755, USA.
| | - Jun Fan
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, 25755, USA
| | - Bryanna Roar
- Department of Pharmaceutical Science and Research, Marshall University School of Pharmacy, Huntington, WV, 25755, USA
| | - Donald A Primerano
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, 25755, USA
| | - James Denvir
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, 25755, USA
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16
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Benzo[a]pyrene activates an AhR/Src/ERK axis that contributes to CYP1A1 induction and stable DNA adducts formation in lung cells. Toxicol Lett 2018; 289:54-62. [DOI: 10.1016/j.toxlet.2018.03.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 02/24/2018] [Accepted: 03/10/2018] [Indexed: 11/20/2022]
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17
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Miret N, Rico-Leo E, Pontillo C, Zotta E, Fernández-Salguero P, Randi A. A dioxin-like compound induces hyperplasia and branching morphogenesis in mouse mammary gland, through alterations in TGF-β1 and aryl hydrocarbon receptor signaling. Toxicol Appl Pharmacol 2017; 334:192-206. [DOI: 10.1016/j.taap.2017.09.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 09/12/2017] [Accepted: 09/14/2017] [Indexed: 12/18/2022]
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18
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Miret N, Pontillo C, Ventura C, Carozzo A, Chiappini F, Kleiman de Pisarev D, Fernández N, Cocca C, Randi A. Hexachlorobenzene modulates the crosstalk between the aryl hydrocarbon receptor and transforming growth factor-β1 signaling, enhancing human breast cancer cell migration and invasion. Toxicology 2016; 366-367:20-31. [PMID: 27519288 DOI: 10.1016/j.tox.2016.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 08/03/2016] [Accepted: 08/08/2016] [Indexed: 12/26/2022]
Abstract
Given the number of women affected by breast cancer, considerable interest has been raised in understanding the relationships between environmental chemicals and disease onset. Hexachlorobenzene (HCB) is a dioxin-like compound that is widely distributed in the environment and is a weak ligand of the aryl hydrocarbon receptor (AhR). We previously demonstrated that HCB acts as an endocrine disruptor capable of stimulating cell proliferation, migration, invasion, and metastasis in different breast cancer models. In addition, increasing evidence indicates that transforming growth factor-β1 (TGF-β1) can contribute to tumor maintenance and progression. In this context, this work investigated the effect of HCB (0.005, 0.05, 0.5, and 5μM) on TGF-β1 signaling and AhR/TGF-β1 crosstalk in the human breast cancer cell line MDA-MB-231 and analyzed whether TGF-β1 pathways are involved in HCB-induced cell migration and invasion. RT-qPCR results indicated that HCB reduces AhR mRNA expression through TGF-β1 signaling but enhances TGF-β1 mRNA levels involving AhR signaling. Western blot analysis demonstrated that HCB could increase TGF-β1 protein levels and activation, as well as Smad3, JNK, and p38 phosphorylation. In addition, low and high doses of HCB were determined to exert differential effects on AhR protein levels, localization, and activation, with a high dose (5μM) inducing AhR nuclear translocation and AhR-dependent CYP1A1 expression. These findings also revealed that c-Src and AhR are involved in HCB-mediated activation of Smad3. HCB enhances cell migration (scratch motility assay) and invasion (Transwell assay) through the Smad, JNK, and p38 pathways, while ERK1/2 is only involved in HCB-induced cell migration. These results demonstrate that HCB modulates the crosstalk between AhR and TGF-β1 and consequently exacerbates a pro-migratory phenotype in MDA-MB-231 cells, which contributes to a high degree of malignancy. Taken together, our findings help to characterize the molecular mechanism underlying the effects of HCB on breast cancer progression.
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Affiliation(s)
- Noelia Miret
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Laboratorio de Efectos Biológicos de Contaminantes Ambientales, Paraguay 2155, 5° piso, (CP1121), Buenos Aires, Argentina.
| | - Carolina Pontillo
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Laboratorio de Efectos Biológicos de Contaminantes Ambientales, Paraguay 2155, 5° piso, (CP1121), Buenos Aires, Argentina.
| | - Clara Ventura
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Físico-Matemática, Laboratorio de Radioisótopos, Junín 954, subsuelo (CP1113), Buenos Aires, Argentina.
| | - Alejandro Carozzo
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, ININFA-CONICET, Laboratorio de Farmacología Molecular, Junín 954, PB, (CP1113), Buenos Aires, Argentina.
| | - Florencia Chiappini
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Laboratorio de Efectos Biológicos de Contaminantes Ambientales, Paraguay 2155, 5° piso, (CP1121), Buenos Aires, Argentina.
| | - Diana Kleiman de Pisarev
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Laboratorio de Efectos Biológicos de Contaminantes Ambientales, Paraguay 2155, 5° piso, (CP1121), Buenos Aires, Argentina.
| | - Natalia Fernández
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, ININFA-CONICET, Laboratorio de Farmacología Molecular, Junín 954, PB, (CP1113), Buenos Aires, Argentina.
| | - Claudia Cocca
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Físico-Matemática, Laboratorio de Radioisótopos, Junín 954, subsuelo (CP1113), Buenos Aires, Argentina.
| | - Andrea Randi
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Laboratorio de Efectos Biológicos de Contaminantes Ambientales, Paraguay 2155, 5° piso, (CP1121), Buenos Aires, Argentina.
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19
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Inhibition of the aryl hydrocarbon receptor prevents Western diet-induced obesity. Model for AHR activation by kynurenine via oxidized-LDL, TLR2/4, TGFβ, and IDO1. Toxicol Appl Pharmacol 2016; 300:13-24. [PMID: 27020609 DOI: 10.1016/j.taap.2016.03.011] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 03/11/2016] [Accepted: 03/21/2016] [Indexed: 12/25/2022]
Abstract
Obesity is an increasingly urgent global problem, yet, little is known about its causes and less is known how obesity can be effectively treated. We showed previously that the aryl hydrocarbon receptor (AHR) plays a role in the regulation of body mass in mice fed Western diet. The AHR is a ligand-activated nuclear receptor that regulates genes involved in a number of biological pathways, including xenobiotic metabolism and T cell polarization. This study was an investigation into whether inhibition of the AHR prevents Western diet-based obesity. Male C57Bl/6J mice were fed control and Western diets with and without the AHR antagonist α-naphthoflavone or CH-223191, and a mouse hepatocyte cell line was used to delineate relevant cellular pathways. Studies are presented showing that the AHR antagonists α-naphthoflavone and CH-223191 significantly reduce obesity and adiposity and ameliorates liver steatosis in male C57Bl/6J mice fed a Western diet. Mice deficient in the tryptophan metabolizing enzyme indoleamine 2,3-dioxygenase 1 (IDO1) were also resistant to obesity. Using an AHR-directed, luciferase-expressing mouse hepatocyte cell line, we show that the transforming growth factor β1 (TGFβ1) signaling pathway via PI3K and NF-κB and the toll-like receptor 2/4 (TLR2/4) signaling pathway stimulated by oxidized low-density lipoproteins via NF-κB, each induce luciferase expression; however, TLR2/4 signaling was significantly reduced by inhibition of IDO1. At physiological levels, kynurenine but not kynurenic acid (both tryptophan metabolites and known AHR agonists) activated AHR-directed luciferase expression. We propose a hepatocyte-based model, in which kynurenine production is increased by enhanced IDO1 activity stimulated by TGFβ1 and TLR2/4 signaling, via PI3K and NF-κB, to perpetuate a cycle of AHR activation to cause obesity; and inhibition of the AHR, in turn, blocks the cycle's output to prevent obesity. The AHR with its broad ligand binding specificity is a promising candidate for a potentially simple therapeutic approach for the prevention and treatment of obesity and associated complications.
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20
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Gao Z, Bu Y, Liu X, Wang X, Zhang G, Wang E, Ding S, Liu Y, Shi R, Li Q, Fu J, Yu Z. TCDD promoted EMT of hFPECs via AhR, which involved the activation of EGFR/ERK signaling. Toxicol Appl Pharmacol 2016; 298:48-55. [PMID: 26971374 DOI: 10.1016/j.taap.2016.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 02/15/2016] [Accepted: 03/08/2016] [Indexed: 02/01/2023]
Abstract
One critical step of second palatal fusion is the newly formed medial epithelia seam (MES) disintegration, which involves apoptosis, epithelial to mesenchymal transition (EMT), and cell migration. Although the environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces cleft palate at high rates, little is known about the effects of TCDD exposure on the fate of palatal epithelial cells. By using primary epithelial cells isolated from human fetal palatal shelves (hFPECs), we show that TCDD increased cell proliferation and EMT, as demonstrated by increased the epithelial markers (E-cadherin and cytokeratin14) and enhanced the mesenchymal markers (vimentin and fibronectin), but had no effect on cell migration and apoptosis. TCDD exposure led to a dose-dependent increase in Slug protein expression. Coimmunoprecipitation revealed that TCDD promoted AhR to form a protein complex with Slug. ChIP assay confirmed that TCDD exposure recruited AhR to the xenobiotic responsive element of Slug promoter. Knockdown of AhR by siRNA remarkably weakened TCDD-induced binding of AhR to the XRE promoter of slug, thereby suppressed TCDD-induced vimentin. Further experiment showed that TCDD stimulated EGFR phosphorylation did not influence the TGFβ3/Smad signaling; whereas TCDD increased phosphorylation of ERK1/2 and p38 with no effect on activation of JNK. By using varieties of inhibitors, we confirmed that TCDD promoted proliferation and EMT of hFPECs via activation of EGFR/ERK pathway. These data make a novel contribution to the molecular mechanism of cleft palate by TCDD.
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Affiliation(s)
- Zhan Gao
- School of Public Health, Xinxiang Medical University, 453003, China; The Fifth Affiliated Hospital, Zhengzhou University, 450052, China
| | - Yongjun Bu
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Xiaozhuan Liu
- Medical College, Henan University of Science & Technology, 471023, China
| | - Xugang Wang
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Guofu Zhang
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Erhui Wang
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Shibin Ding
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Yongfeng Liu
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Ruling Shi
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Qiaoyun Li
- The Fifth Affiliated Hospital, Zhengzhou University, 450052, China
| | - Jianhong Fu
- The Fifth Affiliated Hospital, Zhengzhou University, 450052, China
| | - Zengli Yu
- School of Public Health, Xinxiang Medical University, 453003, China; School of Public Health, Zhengzhou University, 450001, China.
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21
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The aryl hydrocarbon receptor links integrin signaling to the TGF-β pathway. Oncogene 2015; 35:3260-71. [PMID: 26500056 DOI: 10.1038/onc.2015.387] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 08/31/2015] [Accepted: 09/08/2015] [Indexed: 01/02/2023]
Abstract
Glioblastoma is the most common and aggressive form of intrinsic brain tumor. Transforming growth factor (TGF)-β represents a central mediator of the malignant phenotype of these tumors by promoting invasiveness and angiogenesis, maintaining tumor cell stemness and inducing profound immunosuppression. Integrins, which are highly expressed in glioma cells, interact with the TGF-β pathway. Furthermore, a link has been described between activity of the transcription factor aryl hydrocarbon receptor (AhR) and TGF-β expression. Here we demonstrate that integrin inhibition, using αv, β3 or β5 neutralizing antibodies, RNA interference-mediated integrin gene silencing or pharmacological inhibition by the cyclic RGD peptide EMD 121974 (cilengitide) or the non-peptidic molecule GLPG0187, inhibits AhR activity. These effects are independent of cell detachment or cell density. While AhR mRNA expression was not affected by integrin inhibition, AhR total and nuclear protein levels were reduced, suggesting that integrin inhibition-mediated regulation of AhR may occur at a post-transcriptional level. AhR-null astrocytes, AhR-null hepatocytes or glioblastoma cells with a transiently silenced AhR gene showed reduced sensitivity to integrin inhibition-mediated alterations in TGF-β signaling, indicating that AhR mediates integrin control of the TGF-β pathway. Accordingly, there was a significant correlation of αv integrin levels with nuclear AhR and pSmad2 levels as determined by immunohistochemistry in human glioblastoma in vivo. In summary, this study identifies a signaling network comprising integrins, AhR and TGF-β and validates integrin inhibition as a promising strategy not only to inhibit angiogenesis, but also to block AhR- and TGF-β-controlled features of malignancy in human glioblastoma.
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22
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Tarnow P, Tralau T, Luch A. G protein-coupled receptor 30 ligand G-1 increases aryl hydrocarbon receptor signalling by inhibition of tubulin assembly and cell cycle arrest in human MCF-7 cells. Arch Toxicol 2015; 90:1939-48. [DOI: 10.1007/s00204-015-1615-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/01/2015] [Indexed: 11/30/2022]
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23
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Panchanathan R, Liu H, Choubey D. Activation of p53 in Human and Murine Cells by DNA-Damaging Agents Differentially Regulates Aryl Hydrocarbon Receptor Levels. Int J Toxicol 2015; 34:242-9. [PMID: 25878193 DOI: 10.1177/1091581815578013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that regulates multiple cellular processes. The anticancer drug doxorubicin (DOX) can activate AhR-mediated transcription of target genes. Because DOX in cells activates a DNA damage response involving ataxia telangiectasia-mutated (ATM)-mediated activation of p53, we investigated whether the activation of the p53 in cells by DNA-damaging agents such as DOX or bleomycin could regulate the AhR levels. Here we report that activation of p53 by DNA-damaging agents in human cells increased levels of AhR through a posttranscriptional mechanism. Accordingly, fibroblasts from ATM patients, which are defective in p53 activation, expressed reduced constitutive levels of AhR and treatment of cells with bleomycin did not appreciably increase the AhR levels. Further, activation of p53 in cells stimulated the expression of AhR target genes. In murine cells, activation of p53 reduced the levels of AhR messenger RNA and protein and reduced the expression of AhR target genes. Our observations revealed that activation of p53 in human and murine cells differentially regulates AhR levels.
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Affiliation(s)
- Ravichandran Panchanathan
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH, USA Department of Research Cincinnati VA Medical Center, Cincinnati, OH, USA
| | - Hongzhu Liu
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH, USA Department of Research Cincinnati VA Medical Center, Cincinnati, OH, USA
| | - Divaker Choubey
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH, USA Department of Research Cincinnati VA Medical Center, Cincinnati, OH, USA
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24
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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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25
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Aryl hydrocarbon receptor in breast cancer—a newly defined prognostic marker. Discov Oncol 2014; 5:11-21. [PMID: 24078229 DOI: 10.1007/s12672-013-0160-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Accepted: 09/16/2013] [Indexed: 10/26/2022] Open
Abstract
Aryl hydrocarbon receptor (AhR) has been reported to exert various anticancer effects upon breast carcinoma cells in vitro but its details have remained largely unknown. Therefore, we first examined the AhR status in 90 invasive ductal carcinoma patients using immunohistochemistry. We then performed in vitro studies including wound healing assay, invasion assay, and matrix metalloproteinase (MMP) protein array in order to further elucidate the roles of AhR signaling in breast carcinoma. The status of AhR immunoreactivity was inversely correlated with histological grade (P = 0.0135) and Ki-67 labeling index (LI; P = 0.0087) of the patients. In addition, results of both uni- and multivariate analyses revealed that AhR in carcinoma cells turned out an independent prognostic factor with a protective relative risk (P = 0.0179). An administration of 10 nM 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a ligand of AhR, significantly decreased Ki-67 LI in an AhR-dependent fashion in MCF-7, T47D, ZR75-1, and MDA-MB-231. Wound healing and invasion assays performed in T47D and ZR75-1 further demonstrated that 10 nM TCDD inhibited estrogen-induced migration and invasion of cells. MMP proteins associated with AhR in breast carcinoma cells were also firstly identified. These results demonstrated that AhR in breast carcinoma cells is considered a newly defined histological prognostic parameter of the breast cancer patients and effects of AhR activation on proliferation and MMPs expression may be related to the relatively good clinical outcome of AhR-positive breast cancer patients.
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Microarray analysis of gene expression in 3-methylcholanthrene-treated human endothelial cells. Mol Cell Toxicol 2014. [DOI: 10.1007/s13273-014-0003-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Genome-wide data reveal novel genes for methotrexate response in a large cohort of juvenile idiopathic arthritis cases. THE PHARMACOGENOMICS JOURNAL 2014; 14:356-64. [PMID: 24709693 PMCID: PMC4091986 DOI: 10.1038/tpj.2014.3] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 12/16/2013] [Accepted: 12/19/2013] [Indexed: 01/22/2023]
Abstract
Clinical response to methotrexate (MTX) treatment for children with juvenile idiopathic arthritis (JIA) displays considerable heterogeneity. Currently, there are no reliable predictors to identify non-responders: earlier identification could lead to targeted treatment. We genotyped 759 JIA cases from the UK, Netherlands and Czech Republic. Clinical variables were measured at baseline and 6 months after start of treatment. In Phase I analysis samples were analysed for association with MTX response using ordinal regression of ACR-pedi categories and linear regression of change in clinical variables, and identified 31 genetic regions (P<0.001). Phase II analysis increased SNP density in the most strongly associated regions, identifying 14 regions (P<1×10−5): three contain genes of particular biological interest (ZMIZ1, TGIF1 and CFTR). These data suggest a role for novel pathways in MTX response and further investigations within associated regions will help reach our goal of predicting response to MTX in JIA.
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Vogel CFA, Khan EM, Leung PSC, Gershwin ME, Chang WLW, Wu D, Haarmann-Stemmann T, Hoffmann A, Denison MS. Cross-talk between aryl hydrocarbon receptor and the inflammatory response: a role for nuclear factor-κB. J Biol Chem 2014; 289:1866-75. [PMID: 24302727 PMCID: PMC3894361 DOI: 10.1074/jbc.m113.505578] [Citation(s) in RCA: 196] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 11/26/2013] [Indexed: 01/13/2023] Open
Abstract
The aryl hydrocarbon receptor (AhR) is involved in the regulation of immune responses, T-cell differentiation, and immunity. Here, we show that inflammatory stimuli such as LPS induce the expression of AhR in human dendritic cells (DC) associated with an AhR-dependent increase of CYP1A1 (cytochrome P4501A1). In vivo data confirmed the elevated expression of AhR by LPS and the LPS-enhanced 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-mediated induction of CYP1A1 in thymus of B6 mice. Inhibition of nuclear factor-κB (NF-κB) repressed both normal and LPS-enhanced, TCDD-inducible, AhR-dependent gene expression and canonical pathway control of RelA-regulated AhR-responsive gene expression. LPS-mediated induction of AhR was NF-κB-dependent, as shown in mouse embryonic fibroblasts (MEFs) derived from Rel null mice. AhR expression and TCDD-mediated induction of CYP1A1 was significantly reduced in RelA-deficient MEF compared with wild type MEF cells and ectopic expression of RelA restored the expression of AhR and induction of CYP1A1 in MEF RelA null cells. Promoter analysis of the human AhR gene identified three putative NF-κB-binding elements upstream of the transcription start site. Mutation analysis of the AhR promoter identified one NF-κB site as responsible for mediating the induction of AhR expression by LPS and electrophoretic shift assays demonstrated that this NF-κB motif is recognized by the RelA/p50 heterodimer. Our results show for the first time that NF-κB RelA is a critical component regulating the expression of AhR and the induction of AhR-dependent gene expression in immune cells illustrating the interaction of AhR and NF-κB signaling.
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Affiliation(s)
- Christoph F. A. Vogel
- From the Department of Environmental Toxicology
- Center for Health and the Environment
| | | | | | | | - W. L. William Chang
- Center for Comparative Medicine, University of California, Davis, California 95616
| | - Dalei Wu
- the Sanford-Burnham Medical Research Institute, Orlando, Florida 32827
| | | | - Alexander Hoffmann
- the Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90025
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Stobbe-Maicherski N, Wolff S, Wolff C, Abel J, Sydlik U, Frauenstein K, Haarmann-Stemmann T. The interleukin-6-type cytokine oncostatin M induces aryl hydrocarbon receptor expression in a STAT3-dependent manner in human HepG2 hepatoma cells. FEBS J 2013; 280:6681-90. [DOI: 10.1111/febs.12571] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 09/19/2013] [Accepted: 10/10/2013] [Indexed: 12/28/2022]
Affiliation(s)
| | - Sandra Wolff
- IUF - Leibniz Research Institute for Environmental Medicine; Duesseldorf Germany
| | - Christian Wolff
- IUF - Leibniz Research Institute for Environmental Medicine; Duesseldorf Germany
| | - Josef Abel
- IUF - Leibniz Research Institute for Environmental Medicine; Duesseldorf Germany
| | - Ulrich Sydlik
- IUF - Leibniz Research Institute for Environmental Medicine; Duesseldorf Germany
| | - Katrin Frauenstein
- IUF - Leibniz Research Institute for Environmental Medicine; Duesseldorf Germany
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Feng S, Cao Z, Wang X. Role of aryl hydrocarbon receptor in cancer. Biochim Biophys Acta Rev Cancer 2013; 1836:197-210. [PMID: 23711559 DOI: 10.1016/j.bbcan.2013.05.001] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/14/2013] [Accepted: 05/17/2013] [Indexed: 01/01/2023]
Abstract
Aryl hydrocarbon receptor (AHR), a cytosolic ligand-activated transcription factor, belongs to the member of bHLH/PAS family of heterodimeric transcriptional regulators and is widely expressed in a variety of animal species and humans. Recent animal and human data suggested that AHR is involved in various signaling pathways critical to cell normal homeostasis, which covers multiple aspects of physiology, such as cell proliferation and differentiation, gene regulation, cell motility and migration, inflammation and others. Dysregulation of these physiological processes is known to contribute to events such as tumor initiation, promotion, and progression. Increasing epidemiological and experimental animal data provided substantial support for an association between abnormal AHR function and cancer, implicating AHR may be a novel drug-interfering target for cancers. The proposed underlying mechanisms of its actions in cancer involved multiple aspects, (a) inhibiting the functional expression of the key anti-oncogenes (such as p53 and BRCA1), (b) promoting stem cells transforming and angiogenesis, (c) altering cell survival, proliferation and differentiation by influencing the physiologic processes of cell-cycle, apoptosis, cell contact-inhibition, metabolism and remodel of extracellular matrix, and cell-matrix interaction, (d) cross-talking with the signaling pathways of estrogen receptor and inflammation. This review aims to provide a brief overview of recent investigations into the role of AHR and the underlying mechanisms of its actions in cancer, which were explored by the new technologies emerging in recent years.
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Affiliation(s)
- Shaolong Feng
- The School of Public Health, University of South China, Hengyang 421001, China.
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Rico-Leo EM, Alvarez-Barrientos A, Fernandez-Salguero PM. Dioxin receptor expression inhibits basal and transforming growth factor β-induced epithelial-to-mesenchymal transition. J Biol Chem 2013; 288:7841-7856. [PMID: 23382382 DOI: 10.1074/jbc.m112.425009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Recent studies have emphasized the role of the dioxin receptor (AhR) in maintaining cell morphology, adhesion, and migration. These novel AhR functions depend on the cell phenotype, and although AhR expression maintains mesenchymal fibroblasts migration, it inhibits keratinocytes motility. These observations prompted us to investigate whether AhR modulates the epithelial-to-mesenchymal transition (EMT). For this, we have used primary AhR(+/+) and AhR(-/-) keratinocytes and NMuMG cells engineered to knock down AhR levels (sh-AhR) or to express a constitutively active receptor (CA-AhR). Both AhR(-/-) keratinocytes and sh-AhR NMuMG cells had increased migration, reduced levels of epithelial markers E-cadherin and β-catenin, and increased expression of mesenchymal markers Snail, Slug/Snai2, vimentin, fibronectin, and α-smooth muscle actin. Consistently, AhR(+/+) and CA-AhR NMuMG cells had reduced migration and enhanced expression of epithelial markers. AhR activation by the agonist FICZ (6-formylindolo[3,2-b]carbazole) inhibited NMuMG migration, whereas the antagonist α-naphthoflavone induced migration as did AhR knockdown. Exogenous TGFβ exacerbated the promigratory mesenchymal phenotype in both AhR-expressing and AhR-depleted cells, although the effects on the latter were more pronounced. Rescuing AhR expression in sh-AhR cells reduced Snail and Slug/Snai2 levels and cell migration and restored E-cadherin levels. Interference of AhR in human HaCaT cells further supported its role in EMT. Interestingly, co-immunoprecipitation and immunofluorescence assays showed that AhR associates in common protein complexes with E-cadherin and β-catenin, suggesting the implication of AhR in cell-cell adhesion. Thus, basal or TGFβ-induced AhR down-modulation could be relevant in the acquisition of a motile EMT phenotype in both normal and transformed epithelial cells.
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Affiliation(s)
- Eva M Rico-Leo
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain
| | | | - Pedro M Fernandez-Salguero
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain.
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Fardel O. Cytokines as molecular targets for aryl hydrocarbon receptor ligands: implications for toxicity and xenobiotic detoxification. Expert Opin Drug Metab Toxicol 2012; 9:141-52. [PMID: 23230817 DOI: 10.1517/17425255.2013.738194] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
INTRODUCTION The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor historically known for regulating expression of several important drug-detoxifying proteins. Besides drug metabolism pathways, cytokines have been recently recognized as targeted by the AhR signaling cascade, which may contribute to toxicity and changes in xenobiotic detoxification caused by AhR agonists. AREAS COVERED This article summarizes the nature of the main cytokines regulated by AhR ligands and reviews their involvement in toxic effects of AhR ligands, especially in relation with inflammation. The article also discusses the potential implications for drug detoxification pathways. EXPERT OPINION Even if various cytokines, including inflammatory ones, have already been demonstrated to constitute robust targets for AhR, the exact role played by AhR with respect to inflammation remains to be determined. Further studies are also required to better characterize the molecular mechanisms implicated in regulation of cytokines by AhR ligands and to determine the role that may play AhR-targeted cytokines in alteration of xenobiotic detoxification. Finally, changes in cytokine receptor expression triggered by AhR ligands have additionally to be taken into account to better and more extensively comprehend the role played by AhR in the cytokine/inflammation area.
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Affiliation(s)
- Olivier Fardel
- Institut de Recherche en Environnement, Santé et Travail (IRSET)/INSERM U 1085, Faculté de Pharmacie, 2 Avenue du Pr Léon Bernard, 35043 Rennes, France.
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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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Staršíchová A, Hrubá E, Slabáková E, Pernicová Z, Procházková J, Pěnčíková K, Seda V, Kabátková M, Vondráček J, Kozubík A, Machala M, Souček K. TGF-β1 signaling plays a dominant role in the crosstalk between TGF-β1 and the aryl hydrocarbon receptor ligand in prostate epithelial cells. Cell Signal 2012; 24:1665-76. [PMID: 22560882 DOI: 10.1016/j.cellsig.2012.04.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Revised: 04/15/2012] [Accepted: 04/17/2012] [Indexed: 02/06/2023]
Abstract
Crosstalk between the aryl hydrocarbon receptor (AhR) and transforming growth factor-β1 (TGF-β1) signaling has been observed in various experimental models. However, both molecular mechanism underlying this crosstalk and tissue-specific context of this interaction are still only partially understood. In a model of human non-tumorigenic prostate epithelial cells BPH-1, derived from the benign prostatic hyperplasia, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) persistently activates the AhR signaling pathway and induces expression of xenobiotic metabolizing enzymes, such as CYP1A1 or CYP1B1. Here we demonstrate that TGF-β1 suppresses the AhR-mediated gene expression through multiple mechanisms, involving inhibition of AhR expression and down-regulation of nuclear AhR, via a SMAD4-dependent pathway. In contrast, TCDD-induced AhR signaling does not affect either TGF-β1-regulated gene expression or epithelial-to-mesenchymal transition. These observations suggest that, in the context of prostate epithelium, TGF-β1 signaling plays a dominant role in the crosstalk with AhR signaling pathway. Given the importance of TGF-β1 signaling in regulation of prostate epithelial tissue homeostasis, as well as the recently revealed role of AhR in prostate development and tumorigenesis, the above findings contribute to our understanding of the mechanisms underlying the crosstalk between the two signaling pathways in the prostate-specific context.
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Affiliation(s)
- Andrea Staršíchová
- Department of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic
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Abel J, Haarmann-Stemmann T. An introduction to the molecular basics of aryl hydrocarbon receptor biology. Biol Chem 2011; 391:1235-48. [PMID: 20868221 DOI: 10.1515/bc.2010.128] [Citation(s) in RCA: 208] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Depending on their chemical structure and properties, environmental chemicals and other xenobiotics that enter the cell can affect cellular function by either nonselective binding to cellular macromolecules or by interference with cellular receptors, which would initiate a more defined cell biological response. One of these intracellular chemosensor molecules is the aryl hydrocarbon receptor (AhR), a transcription factor of the bHLH/PAS family that is known to mediate the biochemical and toxic effects of dioxins, polyaromatic hydrocarbons and related compounds. Numerous investigations have revealed that the AhR is not only a master regulator of drug metabolism activated by anthropogenic chemicals, but is also triggered by natural and endogenous ligands and can influence cell biological endpoints such as growth and differentiation. Cutting-edge research has identified new intriguing functions of the AhR, such as during proteasomal degradation of steroid hormone receptors, the cellular UVB stress response and the differentiation of certain T-cell subsets. In this review we provide both a survey of the fundamental basics of AhR biology and an insight into new functional aspects of AhR signaling to further stimulate research on this intriguing transcription factor at the interface between toxicology, cell biology and immunology.
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Affiliation(s)
- Josef Abel
- Institut für Umweltmedizinische Forschung (IUF) an der Heinrich-Heine-Universität Düsseldorf gGmbH, Auf'm Hennekamp 50, Düsseldorf, Germany
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Wells PG, Lee CJJ, McCallum GP, Perstin J, Harper PA. Receptor- and reactive intermediate-mediated mechanisms of teratogenesis. Handb Exp Pharmacol 2010:131-162. [PMID: 20020262 DOI: 10.1007/978-3-642-00663-0_6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Drugs and environmental chemicals can adversely alter the development of the fetus at critical periods during pregnancy, resulting in death, or in structural and functional birth defects in the surviving offspring. This process of teratogenesis may not be evident until a decade or more after birth. Postnatal functional abnormalities include deficits in brain function, a variety of metabolic diseases, and cancer. Due to the high degree of fetal cellular division and differentiation, and to differences from the adult in many biochemical pathways, the fetus is highly susceptible to teratogens, typically at low exposure levels that do not harm the mother. Insights into the mechanisms of teratogenesis come primarily from animal models and in vitro systems, and involve either receptor-mediated or reactive intermediate-mediated processes. Receptor-mediated mechanisms involving the reversible binding of xenobiotic substrates to a specific receptor are exemplified herein by the interaction of the environmental chemical 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD or "dioxin") with the cytosolic aryl hydrocarbon receptor (AHR), which translocates to the nucleus and, in association with other proteins, binds to AH-responsive elements (AHREs) in numerous genes, initiating changes in gene transcription that can perturb development. Alternatively, many xenobiotics are bioactivated by fetal enzymes like the cytochromes P450 (CYPs) and prostaglandin H synthases (PHSs) to highly unstable electrophilic or free radical reactive intermediates. Electrophilic reactive intermediates can covalently (irreversibly) bind to and alter the function of essential cellular macromolecules (proteins, DNA), causing developmental anomalies. Free radical reactive intermediates can enhance the formation of reactive oxygen species (ROS), resulting in oxidative damage to cellular macromolecules and/or altered signal transduction. The teratogenicity of reactive intermediates is determined to a large extent by the balance among embryonic and fetal pathways of xenobiotic bioactivation, detoxification of the xenobiotic reactive intermediate, detoxification of ROS, and repair of oxidative macromolecular damage.
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Affiliation(s)
- Peter G Wells
- Division of Biomolecular Sciences, University of Toronto, Toronto, Ontario, Canada.
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37
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Platzer B, Richter S, Kneidinger D, Waltenberger D, Woisetschläger M, Strobl H. Aryl hydrocarbon receptor activation inhibits in vitro differentiation of human monocytes and Langerhans dendritic cells. THE JOURNAL OF IMMUNOLOGY 2009; 183:66-74. [PMID: 19535631 DOI: 10.4049/jimmunol.0802997] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The transcription factor aryl hydrocarbon receptor (AhR) represents a promising therapeutic target in allergy and autoimmunity. AhR signaling induced by the newly described ligand VAF347 inhibits allergic lung inflammation as well as suppresses pancreatic islet allograft rejection. These effects are likely mediated via alterations in dendritic cell (DC) function. Moreover, VAF347 induces tolerogenic DCs. Langerhans cells (LCs) are immediate targets of exogenous AhR ligands at epithelial surfaces; how they respond to AhR ligands remained undefined. We studied AhR expression and function in human LCs and myelopoietic cell subsets using a lineage differentiation and gene transduction model of human CD34(+) hematopoietic progenitors. We found that AhR is highly regulated during myeloid subset differentiation. LCs expressed highest AhR levels followed by monocytes. Conversely, neutrophil granulocytes lacked AhR expression. AhR ligands including VAF347 arrested the differentiation of monocytes and LCs at an early precursor cell stage, whereas progenitor cell expansion or granulopoiesis remained unimpaired. AhR expression was coregulated with the transcription factor PU.1 during myeloid subset differentiation. VAF347 inhibited PU.1 induction during initial monocytic differentiation, and ectopic PU.1 restored monocyte and LC generation in the presence of this compound. AhR ligands failed to interfere with cytokine receptor signaling during LC differentiation and failed to impair LC activation/maturation. VAF347-mediated antiproliferative effect on precursors undergoing LC lineage differentiation occurred in a clinically applicable serum-free culture model and was not accompanied by apoptosis induction. In conclusion, AhR agonist signaling interferes with transcriptional processes leading to monocyte/DC lineage commitment of human myeloid progenitor cells.
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Affiliation(s)
- Barbara Platzer
- Children's Hospital Boston, Harvard Medical School, MA 02115, USA
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38
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Gramatzki D, Pantazis G, Schittenhelm J, Tabatabai G, Köhle C, Wick W, Schwarz M, Weller M, Tritschler I. Aryl hydrocarbon receptor inhibition downregulates the TGF-β/Smad pathway in human glioblastoma cells. Oncogene 2009; 28:2593-605. [DOI: 10.1038/onc.2009.104] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ma C, Marlowe JL, Puga A. The aryl hydrocarbon receptor at the crossroads of multiple signaling pathways. EXS 2009; 99:231-57. [PMID: 19157064 DOI: 10.1007/978-3-7643-8336-7_9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The aryl hydrocarbon receptor (AHR) has long been recognized as a ligand-activated transcription factor responsible for the induction of drug-metabolizing enzymes. Its role in the combinatorial matrix of cell functions was established long before the first report of an AHR cDNA sequence was published. It is only recently that other functions of this protein have begun to be recognized, and it is now clear that the AHR also functions in pathways outside of its well-characterized role in xenobiotic enzyme induction. Perturbation of these pathways by xenobiotic ligands may ultimately explain much of the toxicity of these compounds. This chapter focuses on the interactions of the AHR in pathways critical to cell cycle regulation, mitogen-activated protein kinase cascades, differentiation and apoptosis. Ultimately, the effect of a particular AHR ligand on the biology of the organism will depend on the milieu of critical pathways and proteins expressed in specific cells and tissues with which the AHR itself interacts.
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Affiliation(s)
- Ci Ma
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45220, USA.
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40
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Goldstone HMH, Stegeman JJ. Molecular Mechanisms of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin Cardiovascular Embryotoxicity. Drug Metab Rev 2008; 38:261-89. [PMID: 16684661 DOI: 10.1080/03602530600570099] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
2,3,7,8 Tetrachlorodibenzo-p-dioxin (TCDD) and related planar halogenated aromatic hydrocarbons are widespread environmental contaminants and potent developmental toxicants. Hallmarks of embryonic exposure include edema, hemorrhage, and mortality. Recent studies in zebrafish and chicken have revealed direct impairment of cardiac muscle growth that may underlie these overt symptoms. TCDD toxicity is mediated by the aryl hydrocarbon receptor, but downstream targets remain unclear. Oxidative stress and growth factor modulation have been implicated in TCDD cardiovascular toxicity. Gene expression profiling is elucidating additional pathways by which TCDD might act. We review our understanding of the mechanism of TCDD embryotoxicity at morphological and molecular levels.
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Affiliation(s)
- Heather M H Goldstone
- The Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA 02543, USA.
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Haarmann-Stemmann T, Bothe H, Abel J. Growth factors, cytokines and their receptors as downstream targets of arylhydrocarbon receptor (AhR) signaling pathways. Biochem Pharmacol 2008; 77:508-20. [PMID: 18848820 DOI: 10.1016/j.bcp.2008.09.013] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 09/12/2008] [Accepted: 09/12/2008] [Indexed: 01/02/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a widespread environmental pollutant, which causes a variety of severe health effects, e.g. immunosuppression, hepatotoxicity, and carcinogenesis. The main mediator of TCDD toxicity is the arylhydrocarbon receptor (AhR), which, upon activation, translocates into the nucleus and enforces gene expression. Since most of the pleiotropic effects caused by TCDD are associated with alterations in cell growth and differentiation, the analysis of the interference of the AhR with factors controlling these cellular functions seems to be a promising target regarding the prevention and treatment of chemical-provoked diseases. Cell growth and differentiation are regulated by numerous growth factors and cytokines. These multifunctional peptides promote or inhibit cell growth and regulate differentiation and other cellular processes, depending on cell-type and developmental stage. They are involved in the regulation of a broad range of physiological processes, including immune response, hematopoiesis, neurogenesis, and tissue remodeling. The complex network of growth factors and cytokines is accurately regulated and disturbances of this system are associated with adverse health effects. The molecular mechanisms by which the AhR interferes with this signaling network are multifaceted and the physiological consequences of this cross-talk are quite enigmatic. The investigation of this complex interaction is an exciting task, especially with respect to the recently described non-genomic and/or ligand-independent activities of AhR. Therefore, we summarize the current knowledge about the interaction of the AhR with three cytokine-/growth factor-related signal transducers -- the epidermal growth factor (EGF) family, tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor-beta (TGF-beta) -- with regard to pathophysiological findings.
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Gomez-Duran A, Carvajal-Gonzalez JM, Mulero-Navarro S, Santiago-Josefat B, Puga A, Fernandez-Salguero PM. Fitting a xenobiotic receptor into cell homeostasis: how the dioxin receptor interacts with TGFbeta signaling. Biochem Pharmacol 2008; 77:700-12. [PMID: 18812170 DOI: 10.1016/j.bcp.2008.08.032] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 08/07/2008] [Accepted: 08/08/2008] [Indexed: 02/06/2023]
Abstract
As our knowledge on the mechanisms that control cell function increases, more complex signaling pathways and quite intricate cross-talks among regulatory proteins are discovered. Establishing accurate interactions between cellular networks is essential for a healthy cell and different alterations in signaling are known to underline human disease. Transforming growth factor beta (TGFbeta) is an extracellular cytokine that regulates such critical cellular responses as proliferation, apoptosis, differentiation, angiogenesis and migration, and it is assumed that the latency-associated protein LTBP-1 plays a relevant role in TGFbeta targeting and activation in the extracellular matrix (ECM). The dioxin receptor (AhR) is a unique intracellular protein long studied because of its critical role in xenobiotic-induced toxicity and carcinogenesis. Yet, a large set of studies performed in cellular systems and in vivo animal models have suggested important xenobiotic-independent functions for AhR in cell proliferation, differentiation and migration and in tissue homeostasis. Remarkably, AhR activity converges with TGFbeta-dependent signaling through LTBP-1 since cells lacking AhR expression have phenotypic alterations that can be explained, at least in part, by the coordinated regulation of both proteins. Here, we will discuss the existence of functional interactions between AhR and TGFbeta signaling. We will focus on regulatory and functional aspects by analyzing how AhR status determines TGFbeta activity and by proposing a mechanism through which LTBP-1, a novel AhR target gene, mediates such effects. We will integrate ECM proteases in the AhR-LTBP-1-TGFbeta axis and suggest a model that could help explain some in vivo phenotypes associated to AhR deficiency.
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Affiliation(s)
- Aurea Gomez-Duran
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
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Interaction between the aryl hydrocarbon receptor and transforming growth factor-beta signaling pathways: evidence of an asymmetrical relationship in rat granulosa cells. Biochem Pharmacol 2008; 76:1165-74. [PMID: 18786509 DOI: 10.1016/j.bcp.2008.08.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 08/09/2008] [Accepted: 08/14/2008] [Indexed: 12/30/2022]
Abstract
The aryl hydrocarbon receptor (AHR) mediates toxic responses to environmental contaminants and plays pivotal physiological roles in various biological processes as well, particularly in ovarian function. It is well documented that expression and function of the AHR is negatively regulated by transforming growth factor-beta (TGF-beta) in many cell types. In addition, several studies indicate that AHR activity inhibits TGF-beta expression and function in some systems. However, the interplay between these two signals is highly dependent upon the cell type being studied, precluding a generalization about the outcome of such interaction. Therefore, the goal of the present study was to determine the effect of TGF-beta on AHR expression and activation in granulosa cells, an ovarian cell type where the growth factor is mitogenic and AHR activation has been associated with promotion of proliferation as well. In addition, we conducted experiments aimed at evaluating the effect of AHR ligands on TGF-beta action in our system. Results presented herein demonstrate that AHR expression is not regulated by TGF-beta in rat granulosa cells, neither at the mRNA level nor at the protein level. Moreover, we find that the growth factor does not alter the transcriptional function of the AHR. Conversely, we show that activation of AHR by an agonist deregulates TGF-beta function in granulosa cells, inhibiting its transcriptional activity and its mitogenic action. The described one-sided interplay between TGF-beta and AHR signaling pathway may help provide a mechanistic explanation to some of the physiological outcomes of AHR or TGF-beta activation in granulosa cells.
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Quintana FJ, Basso AS, Iglesias AH, Korn T, Farez MF, Bettelli E, Caccamo M, Oukka M, Weiner HL. Control of T(reg) and T(H)17 cell differentiation by the aryl hydrocarbon receptor. Nature 2008; 453:65-71. [PMID: 18362915 DOI: 10.1038/nature06880] [Citation(s) in RCA: 1369] [Impact Index Per Article: 85.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Accepted: 02/04/2008] [Indexed: 12/14/2022]
Abstract
Regulatory T cells (T(reg)) expressing the transcription factor Foxp3 control the autoreactive components of the immune system. The development of T(reg) cells is reciprocally related to that of pro-inflammatory T cells producing interleukin-17 (T(H)17). Although T(reg) cell dysfunction and/or T(H)17 cell dysregulation are thought to contribute to the development of autoimmune disorders, little is known about the physiological pathways that control the generation of these cell lineages. Here we report the identification of the ligand-activated transcription factor aryl hydrocarbon receptor (AHR) as a regulator of T(reg) and T(H)17 cell differentiation in mice. AHR activation by its ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin induced functional T(reg) cells that suppressed experimental autoimmune encephalomyelitis. On the other hand, AHR activation by 6-formylindolo[3,2-b]carbazole interfered with T(reg) cell development, boosted T(H)17 cell differentiation and increased the severity of experimental autoimmune encephalomyelitis in mice. Thus, AHR regulates both T(reg) and T(H)17 cell differentiation in a ligand-specific fashion, constituting a unique target for therapeutic immunomodulation.
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Affiliation(s)
- Francisco J Quintana
- Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA
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Mortensen AS, Braathen M, Sandvik M, Arukwe A. Effects of hydroxy-polychlorinated biphenyl (OH-PCB) congeners on the xenobiotic biotransformation gene expression patterns in primary culture of Atlantic salmon (Salmo salar) hepatocytes. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2007; 68:351-60. [PMID: 17207528 DOI: 10.1016/j.ecoenv.2006.11.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2006] [Revised: 10/24/2006] [Accepted: 11/26/2006] [Indexed: 05/13/2023]
Abstract
Hydroxylated metabolites of PCBs [OH-PCBs] represent new health and environmental concern because they have been shown to have agonist or antagonist interactions with hormone receptors (HRs) or hormone-receptor mediated responses. The present study was designed to investigate the estrogenic potency based on anti-AhR signalling effect of three 4-OH substituted PCB congeners (#107, #146 and #187), one 3-OH substituted congener (#138), and the pharmaceutical synthetic estrogen, ethynylestradiol (EE2) in fish in vitro system using primary culture of Atlantic salmon hepatocytes. The effects were studied by quantifying changes in transcripts with gene-sequence primer pairs for a suite of gene responses (AhRalpha, ARNT, CYP1A1, CYP3A, UGT and GST) belonging to the xenobiotic biotransformation system. Our data show that OH-PCB congeners and EE2, decreased AhRalpha and ARNT transcript levels, and CYP1A1, UGT and GST gene expressions, together with CYP3A gene expression. The decreased expression of transcripts for xenobiotic biotransformation system is related to the concentration of individual OH-PCB congener and these responses are typical of reported estrogenic and estrogen-like effects on the CYP system. Modulation of biotransformation pathways by OH-PCBs may alter xenobiotic metabolism leading to the production of toxic reactive molecules, altering pharmacokinetics and diminishing the clearance rate of individual chemicals from the organism.
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Affiliation(s)
- Anne S Mortensen
- Department of Biology, Norwegian University of Science and Technology (NTNU), Høgskoleringen 5, 7491 Trondheim, Norway
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Chang X, Fan Y, Karyala S, Schwemberger S, Tomlinson CR, Sartor MA, Puga A. Ligand-independent regulation of transforming growth factor beta1 expression and cell cycle progression by the aryl hydrocarbon receptor. Mol Cell Biol 2007; 27:6127-39. [PMID: 17606626 PMCID: PMC1952156 DOI: 10.1128/mcb.00323-07] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that mediates the toxic effects of its xenobiotic ligands and acts as an environmental checkpoint during the cell cycle. We expressed stably integrated, Tet-Off-regulated AHR variants in fibroblasts from AHR-null mice to further investigate the AHR role in cell cycle regulation. Ahr+/+ fibroblasts proliferated significantly faster than Ahr-/- fibroblasts did, and exposure to a prototypical AHR ligand or deletion of the ligand-binding domain did not change their proliferation rates, indicating that the AHR function in cell cycle was ligand independent. Growth-promoting genes, such as cyclin and cyclin-dependent kinase genes, were significantly down-regulated in Ahr-/- cells, whereas growth-arresting genes, such as the transforming growth factor beta1 (TGF-beta1) gene, extracellular matrix (ECM)-related genes, and cyclin-dependent kinase inhibitor genes, were up-regulated. Ahr-/- fibroblasts secreted significantly more TGF-beta1 into the culture medium than Ahr+/+ fibroblasts did, and Ahr-/- showed increased levels of activated Smad4 and TGF-beta1 mRNA. Inhibition of TGF-beta1 signaling by overexpression of Smad7 reversed the proliferative and gene expression phenotype of Ahr-/- fibroblasts. Changes in TGF-beta1 mRNA accumulation were due to stabilization resulting from decreased activity of TTP, the tristetraprolin RNA-binding protein responsible for mRNA destabilization through AU-rich motifs. These results show that the Ah receptor possesses interconnected intrinsic cellular functions, such as ECM formation, cell cycle control, and TGF-beta1 regulation, that are independent of activation by either exogenous or endogenous ligands and that may play a crucial role during tumorigenesis.
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Affiliation(s)
- Xiaoqing Chang
- Department of Environmental Health, University of Cincinnati Medical Center, and Shriners Hospital for Children, Cincinnati, OH 45267-0056, USA
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Fritsche E, Schäfer C, Calles C, Bernsmann T, Bernshausen T, Wurm M, Hübenthal U, Cline JE, Hajimiragha H, Schroeder P, Klotz LO, Rannug A, Fürst P, Hanenberg H, Abel J, Krutmann J. Lightening up the UV response by identification of the arylhydrocarbon receptor as a cytoplasmatic target for ultraviolet B radiation. Proc Natl Acad Sci U S A 2007; 104:8851-6. [PMID: 17502624 PMCID: PMC1885591 DOI: 10.1073/pnas.0701764104] [Citation(s) in RCA: 328] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
UVB radiation-induced signaling in mammalian cells involves two major pathways: one that is initiated through the generation of DNA photoproducts in the nucleus and a second one that occurs independently of DNA damage and is characterized by cell surface receptor activation. The chromophore for the latter one has been unknown. Here, we report that the UVB response involves tryptophan as a chromophore. We show that through the intracellular generation of photoproducts, such as the arylhydrocarbon receptor (AhR) ligand 6-formylindolo[3,2-b]carbazole, signaling events are initiated, which are transferred to the nucleus and the cell membrane via activation of the cytoplasmatic AhR. Specifically, AhR activation by UVB leads to (i) transcriptional induction of cytochrome P450 1A1 and (ii) EGF receptor internalization with activation of the EGF receptor downstream target ERK1/2 and subsequent induction of cyclooxygenase-2. The role of the AhR in the UVB stress response was confirmed in vivo by studies employing AhR KO mice.
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Affiliation(s)
- Ellen Fritsche
- *Institut für Umweltmedizinische Forschung (IUF), Auf'm Hennekamp 50, 40225 Düsseldorf, Germany
| | - Claudia Schäfer
- *Institut für Umweltmedizinische Forschung (IUF), Auf'm Hennekamp 50, 40225 Düsseldorf, Germany
| | - Christian Calles
- *Institut für Umweltmedizinische Forschung (IUF), Auf'm Hennekamp 50, 40225 Düsseldorf, Germany
| | - Thorsten Bernsmann
- Chemical and Veterinary Control Laboratory, Josef-König-Strasse 40, 48147 Münster, Germany
| | - Thorsten Bernshausen
- *Institut für Umweltmedizinische Forschung (IUF), Auf'm Hennekamp 50, 40225 Düsseldorf, Germany
| | - Melanie Wurm
- Department of Pediatric Oncology, Hematology, and Immunology, Children's Hospital, Heinrich Heine University Medical Center, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Ulrike Hübenthal
- *Institut für Umweltmedizinische Forschung (IUF), Auf'm Hennekamp 50, 40225 Düsseldorf, Germany
| | - Jason E. Cline
- *Institut für Umweltmedizinische Forschung (IUF), Auf'm Hennekamp 50, 40225 Düsseldorf, Germany
| | - Hossein Hajimiragha
- *Institut für Umweltmedizinische Forschung (IUF), Auf'm Hennekamp 50, 40225 Düsseldorf, Germany
| | - Peter Schroeder
- *Institut für Umweltmedizinische Forschung (IUF), Auf'm Hennekamp 50, 40225 Düsseldorf, Germany
| | - Lars-Oliver Klotz
- Institute for Biochemistry und Molecular Biology I, Heinrich Heine University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Agneta Rannug
- Institute of Environmental Medicine, Karolinska Institutet, Box 210, S-171 77 Stockholm, Sweden; and
| | - Peter Fürst
- Chemical and Veterinary Control Laboratory, Josef-König-Strasse 40, 48147 Münster, Germany
| | - Helmut Hanenberg
- Department of Pediatric Oncology, Hematology, and Immunology, Children's Hospital, Heinrich Heine University Medical Center, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Josef Abel
- *Institut für Umweltmedizinische Forschung (IUF), Auf'm Hennekamp 50, 40225 Düsseldorf, Germany
| | - Jean Krutmann
- *Institut für Umweltmedizinische Forschung (IUF), Auf'm Hennekamp 50, 40225 Düsseldorf, Germany
- To whom correspondence should be addressed. E-mail:
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Ross KR, Corey DA, Dunn JM, Kelley TJ. SMAD3 expression is regulated by mitogen-activated protein kinase kinase-1 in epithelial and smooth muscle cells. Cell Signal 2007; 19:923-31. [PMID: 17197157 DOI: 10.1016/j.cellsig.2006.11.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2006] [Revised: 11/01/2006] [Accepted: 11/07/2006] [Indexed: 10/23/2022]
Abstract
SMAD3 is a transcription factor that mediates TGF-beta1 signaling and is known to be important in many of the cellular processes that regulate fibrosis and inflammation. Although several studies have examined SMAD3 activation, little is known about the control of SMAD3 expression. It is well established that the mitogen-activated protein kinase (MAPK) pathway is responsive to TGF-beta1 stimulation and coordinates with SMAD signaling in many cases; therefore, the hypothesis of this study is that the MAPK pathway will be involved in the regulation of SMAD3 expression. Using a SMAD3 promoter construct, we demonstrate that inhibition of either c-Jun-N-terminal kinase (JNK) or p38 activity has little effect on SMAD3 promoter function. Inhibition of mitogen-activated protein kinase kinase-1 (MEK1) with either PD98059 or UO126, however, results in a substantial dose-dependent inhibition of SMAD3 promoter activity. Further studies confirm that promoter activity correlates with protein expression by demonstrating reduced SMAD3 protein expression in A549 cells and airway smooth muscle cells after treatment with MEK1 inhibitors. Positive regulation of SMAD3 expression is also demonstrated by expression of a constitutively active (ca)-MEK1 construct, where the presence of ca-MEK1 resulted in increased SMAD3 protein expression. These data lead to the conclusion that MEK1 is an important regulator of SMAD3 expression.
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Affiliation(s)
- Kristie R Ross
- Department of Pediatrics, Case Western Reserve University, and Rainbow Babies and Children's Hospital, Cleveland, OH 44106-4948, USA
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Suh JH, Huang J, Park YY, Seong HA, Kim D, Shong M, Ha H, Lee IK, Lee K, Wang L, Choi HS. Orphan nuclear receptor small heterodimer partner inhibits transforming growth factor-beta signaling by repressing SMAD3 transactivation. J Biol Chem 2006; 281:39169-78. [PMID: 17074765 DOI: 10.1074/jbc.m605947200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Orphan nuclear receptor small heterodimer partner (SHP) is an atypical member of the nuclear receptor superfamily; SHP regulates the nuclear receptor-mediated transcription of target genes but lacks a conventional DNA binding domain. In this study, we demonstrate that SHP represses transforming growth factor-beta (TGF-beta)-induced gene expression through a direct interaction with Smad, a transducer of TGF-beta signaling. Transient transfection studies demonstrate that SHP represses Smad3-induced transcription. In vivo and in vitro protein interaction assays revealed that SHP directly interacts with Smad2 and Smad3 but not with Smad4. Mapping of domains mediating the interaction between SHP and Smad3 showed that the entire N-terminal domain (1-159 amino acids) of SHP and the linker domain of Smad3 are involved in this interaction. In vitro glutathione S-transferase pulldown competition experiments revealed the SHP-mediated repression of Smad3 transactivation through competition with its co-activator p300. SHP also inhibits the activation of endogenous TGF-beta-responsive gene promoters, the p21, Smad7, and plasminogen activator inhibitor-1 (PAI-1) promoters. Moreover, adenovirus-mediated overexpression of SHP decreases PAI-1 mRNA levels, and down-regulation of SHP by a small interfering RNA increases both the transactivation of Smad3 and the PAI-1 mRNA levels. Finally, the PAI-1 gene is expressed in SHP(-/-) mouse hepatocytes at a higher level than in normal hepatocytes. Taken together, these data indicate that SHP is a novel co-regulator of Smad3, and this study provides new insights into regulation of TGF-beta signaling.
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Affiliation(s)
- Ji Ho Suh
- Hormone Research Center, School of Biological Science and Technology, Chonnam National University, Kwangju 500-757, Republic of Korea
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Bussmann UA, Barañao JL. Regulation of Aryl Hydrocarbon Receptor Expression in Rat Granulosa Cells1. Biol Reprod 2006; 75:360-9. [PMID: 16738223 DOI: 10.1095/biolreprod.106.053017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that mediates most of the toxic and endocrine-disruptive actions of aromatic compounds in the ovary. Paradoxically, this receptor has been shown to play important roles in normal female reproductive function as well. Although knowledge of AHR expression regulation in the ovary is of crucial significance to understand the receptor biology and its function in reproductive physiology, there are only limited data in this area. The purpose of the present study was to establish the possible regulation that AHR might undergo in ovarian cells. Here we show that the hormones FSH and estradiol are able to reduce AHR protein and transcript levels in granulosa cells in a way that parallels the changes observed in ovarian tissue across the rat estrous cycle. These findings suggest that estradiol and FSH would be cycle-associated endogenous modulators of AHR expression. In addition, we show that in granulosa cells the receptor is rapidly downregulated via proteasomal degradation following treatment with AHR ligands. However, prolonged treatment with an agonist caused an increase in Ahr mRNA levels. These actions would constitute a regulatory mechanism that both attenuates AHR signal rapidly and replenishes the cellular receptor pool in the long term. In conclusion, our results indicate that AHR expression is regulated by classical hormones and by its own ligands in granulosa cells.
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