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Opitz CA, Holfelder P, Prentzell MT, Trump S. The complex biology of aryl hydrocarbon receptor activation in cancer and beyond. Biochem Pharmacol 2023; 216:115798. [PMID: 37696456 PMCID: PMC10570930 DOI: 10.1016/j.bcp.2023.115798] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/08/2023] [Accepted: 09/08/2023] [Indexed: 09/13/2023]
Abstract
The aryl hydrocarbon receptor (AHR) signaling pathway is a complex regulatory network that plays a critical role in various biological processes, including cellular metabolism, development, and immune responses. The complexity of AHR signaling arises from multiple factors, including the diverse ligands that activate the receptor, the expression level of AHR itself, and its interaction with the AHR nuclear translocator (ARNT). Additionally, the AHR crosstalks with the AHR repressor (AHRR) or other transcription factors and signaling pathways and it can also mediate non-genomic effects. Finally, posttranslational modifications of the AHR and its interaction partners, epigenetic regulation of AHR and its target genes, as well as AHR-mediated induction of enzymes that degrade AHR-activating ligands may contribute to the context-specificity of AHR activation. Understanding the complexity of AHR signaling is crucial for deciphering its physiological and pathological roles and developing therapeutic strategies targeting this pathway. Ongoing research continues to unravel the intricacies of AHR signaling, shedding light on the regulatory mechanisms controlling its diverse functions.
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Affiliation(s)
- Christiane A Opitz
- German Cancer Research Center (DKFZ), Heidelberg, Division of Metabolic Crosstalk in Cancer and the German Cancer Consortium (DKTK), DKFZ Core Center Heidelberg, 69120 Heidelberg, Germany; Neurology Clinic and National Center for Tumor Diseases, 69120 Heidelberg, Germany.
| | - Pauline Holfelder
- German Cancer Research Center (DKFZ), Heidelberg, Division of Metabolic Crosstalk in Cancer and the German Cancer Consortium (DKTK), DKFZ Core Center Heidelberg, 69120 Heidelberg, Germany; Faculty of Bioscience, Heidelberg University, 69120 Heidelberg, Germany
| | - Mirja Tamara Prentzell
- German Cancer Research Center (DKFZ), Heidelberg, Division of Metabolic Crosstalk in Cancer and the German Cancer Consortium (DKTK), DKFZ Core Center Heidelberg, 69120 Heidelberg, Germany; Faculty of Bioscience, Heidelberg University, 69120 Heidelberg, Germany
| | - Saskia Trump
- Molecular Epidemiology Unit, Berlin Institute of Health at Charité and the German Cancer Consortium (DKTK), Partner Site Berlin, a partnership between DKFZ and Charité -Universitätsmedizin Berlin, 10117 Berlin, Germany
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2
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Chen Z, Li Y, Xie Y, Nie S, Chen B, Wu Z. Roflumilast enhances the melanogenesis and attenuates oxidative stress-triggered damage in melanocytes. J Dermatol Sci 2023:S0923-1811(23)00080-4. [PMID: 37069030 DOI: 10.1016/j.jdermsci.2023.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/28/2023] [Accepted: 04/02/2023] [Indexed: 04/05/2023]
Abstract
BACKGROUND The management of vitiligo is challenging due to limited treatment options, and therapeutic strategy varies according to the active or stable stage of vitiligo. PDE4 inhibitor has been used to treat various skin diseases, but the efficacy in vitiligo treatment is mixed. OBJECTIVE In this study, we aimed to investigate whether roflumilast, a PDE4 inhibitor, induces melanogenesis and attenuates oxidative stress-triggered damage in melanocytes, and if so, what is the mechanism. METHODS Melanin content assay, qRT-PCR, western blotting, ELISA, immunofluorescence assays, immunohistochemistry, small interfering RNA, flow cytometry, and transmission electron microscopy were employed. RESULTS Our results demonstrated that roflumilast alone only slightly increased melanogenesis, however, the combination of roflumilast and forskolin could boost cAMP levels, hence promoting melanogenesis more significantly. Moreover, roflumilast attenuated H2O2-induced apoptosis and mitochondrial morphological changes in melanocytes by reducing ROS levels. Furthermore, roflumilast activated AhR/Nrf2 pathway via cAMP whereas AhR silencing blocked roflumilast-induced Nrf2 nuclear translocation and reversed the inhibitory effect of roflumilast on H2O2-induced ROS production. Finally, we observed that the lesional skin of active vitiligo patients exhibited higher PDE4 expression levels. CONCLUSION roflumilast enhances the melanogenesis effect of forskolin and protects melanocytes from H2O2-induced apoptosis by cAMP/AhR/Nrf2-activated ROS inhibition, highlighting its therapeutic potential in vitiligo treatment.
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3
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Singleman C, Holtzman NG. PCB and TCDD derived embryonic cardiac defects result from a novel AhR pathway. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2021; 233:105794. [PMID: 33662880 DOI: 10.1016/j.aquatox.2021.105794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 01/30/2021] [Accepted: 02/20/2021] [Indexed: 06/12/2023]
Abstract
Polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are environmental contaminants known to impact cardiac development, a key step in the embryonic development of most animals. To date, little is understood of the molecular mechanism driving the observed cardiac defects in exposed fishes. The literature shows PCB & TCDD derived cardiac defects are concurrent with, but not caused by, expression of cyp1A, due to activation of the aryl hydrocarbon receptor (AhR) gene activation pathway. However, in this study, detailed visualization of fish hearts exposed to PCBs and TCDD show that, in addition to a failure of cardiac looping in early heart development, the inner endocardial lining of the heart fails to maintain proper cell adhesion and tissue integrity. The resulting gap between the endocardium and myocardium in both zebrafish and Atlantic sturgeon suggested functional faults in endothelial adherens junction formation. Thus, we explored the molecular mechanism triggering cardiac defects using immunohistochemistry to identify the location and phosphorylation state of key regulatory and adhesion molecules. We hypothesized that PCB and TCDD activates AhR, phosphorylating Src, which then phosphorylates the endothelial adherens junction protein, VEcadherin. When phosphorylated, VEcadherin dimers, found in the endocardium and vasculature, separate, reducing tissue integrity. In zebrafish, treatment with PCB and TCDD contaminants leads to higher phosphorylation of VEcadherin in cardiac tissue suggesting that these cells have reduced connectivity. Small molecule inhibition of Src phosphorylation prevents contaminant stimulated phosphorylation of VEcadherin and rescues both cardiac function and gross morphology. Atlantic sturgeon hearts show parallels to contaminant exposed zebrafish cardiac phenotype at the tissue level. These data suggest that the mechanism for PCB and TCDD action in the heart is, in part, distinct from the canonical mechanism described in the literature and that cardiac defects are impacted by this nongenomic mechanism.
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Affiliation(s)
- Corinna Singleman
- Department of Biology, Queens College, City University of New York, 65-30 Kissena Blvd, Queens NY 11367-1597, USA; The Graduate Center, City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
| | - Nathalia G Holtzman
- Department of Biology, Queens College, City University of New York, 65-30 Kissena Blvd, Queens NY 11367-1597, USA; The Graduate Center, City University of New York, 365 Fifth Avenue, New York, NY 10016, USA.
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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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Kim JW, Im I, Kim H, Jeon JS, Kang EH, Jo S, Chun HS, Yoon S, Kim JH, Kim SK, Park HJ. Live-cell screening platform using human-induced pluripotent stem cells expressing fluorescence-tagged cytochrome P450 1A1. FASEB J 2020; 34:9141-9155. [PMID: 32421247 DOI: 10.1096/fj.201903110r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/04/2020] [Accepted: 04/21/2020] [Indexed: 12/12/2022]
Abstract
Human-induced pluripotent stem cells (hiPSCs) are invaluable sources for drug screening and toxicity tests because of their differentiation potential and proliferative capacity. Recently, the CRISPR-Cas9-mediated homologous recombination system has enabled reporter knock-ins at desired loci in hiPSCs, and here, we generated a hiPSC reporter line expressing mCherry-tagged cytochrome P450 1A1 (CYP1A1), which can be utilized to screen for the modulators of aryl hydrocarbon receptor (AHR) in live cells. CYP1A1-mCherry hiPSCs exhibited typical characteristics of pluripotent stem cells such as marker expression, differentiation potential, and normal karyotype. After differentiation into hepatocyte-like cells (HLCs), CYP1A1-mCherry fusion protein was expressed and localized at the endoplasmic reticulum, and induced by AHR agonists. We obtained 23 hits modulating CYP1A1 expression from high-content screening with 241 hepatotoxicity chemicals and nuclear receptor ligands, and identified three upregulating chemicals and two downregulating compounds. Responses of hiPSC-HLCs against an AHR agonist were more similar to human primary hepatocytes than of HepG2 hepatocellular carcinoma cells. This platform has the advantages of live-cell screening without sacrificing cells (unlike previously available CYP1A1 reporter cell lines), as well as an indefinite supply of cells, and can be utilized in a wide range of screening related to AHR- and CYP1A1-associated diseases in desired cell types.
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Affiliation(s)
- Ji-Woo Kim
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon, Republic of Korea
| | - Ilkyun Im
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon, Republic of Korea
| | - Hyemin Kim
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon, Republic of Korea
| | - Jang Su Jeon
- College of Pharmacy, Chungnam National University, Daejeon, Republic of Korea
| | - Eun-Hye Kang
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon, Republic of Korea.,Human and Environmental Toxicology, School of Engineering, University of Science and Technology, Daejeon, Republic of Korea
| | - Seongyea Jo
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon, Republic of Korea.,Department of Biotechnology, College of Life Science and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Hang-Suk Chun
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon, Republic of Korea
| | - Seokjoo Yoon
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon, Republic of Korea.,Human and Environmental Toxicology, School of Engineering, University of Science and Technology, Daejeon, Republic of Korea
| | - Jong-Hoon Kim
- Department of Biotechnology, College of Life Science and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Sang Kyum Kim
- College of Pharmacy, Chungnam National University, Daejeon, Republic of Korea
| | - Han-Jin Park
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon, Republic of Korea
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Nieto C, Rayo I, de Las Casas-Engel M, Izquierdo E, Alonso B, Béchade C, Maroteaux L, Vega MA, Corbí ÁL. Serotonin (5-HT) Shapes the Macrophage Gene Profile through the 5-HT 2B-Dependent Activation of the Aryl Hydrocarbon Receptor. THE JOURNAL OF IMMUNOLOGY 2020; 204:2808-2817. [PMID: 32253244 DOI: 10.4049/jimmunol.1901531] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 03/16/2020] [Indexed: 12/13/2022]
Abstract
Macrophages can either promote or resolve inflammatory responses, and their polarization state is modulated by peripheral serotonin (5-hydroxytryptamine [5-HT]). In fact, pro- and anti-inflammatory macrophages differ in the expression of serotonin receptors, with 5-HT2B and 5-HT7 expression restricted to M-CSF-primed monocyte-derived macrophages (M-MØ). 5-HT7 drives the acquisition of profibrotic and anti-inflammatory functions in M-MØ, whereas 5-HT2B prevents the degeneration of spinal cord mononuclear phagocytes and modulates motility of murine microglial processes. Because 5-HT2B mediates clinically relevant 5-HT-related pathologies (valvular heart disease, pulmonary arterial hypertension) and is an off target of anesthetics, antiparkinsonian drugs, and selective serotonin reuptake inhibitors, we sought to determine the transcriptional consequences of 5-HT2B engagement in human macrophages, for which 5-HT2B signaling remains unknown. Assessment of the effects of specific agonists and antagonist revealed that 5-HT2B engagement modifies the cytokine and gene signature of anti-inflammatory M-MØ, upregulates the expression of aryl hydrocarbon receptor (AhR) target genes, and stimulates the transcriptional activation of AhR. Moreover, we found that 5-HT dose dependently upregulates the expression of AhR target genes in M-MØ and that the 5-HT-mediated activation of AhR is 5-HT2B dependent because it is abrogated by the 5-HT2B-specific antagonist SB204741. Altogether, our results demonstrate the existence of a functional 5-HT/5-HT2B/AhR axis in human macrophages and indicate that 5-HT potentiates the activity of a transcription factor (AhR) that regulates immune responses and the biological responses to xenobiotics.
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Affiliation(s)
- Concha Nieto
- Laboratorio de Células Mieloides, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain;
| | - Ignacio Rayo
- Laboratorio de Células Mieloides, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain
| | - Mateo de Las Casas-Engel
- Laboratorio de Células Mieloides, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain
| | - Elena Izquierdo
- Laboratorio de Células Mieloides, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain
| | - Bárbara Alonso
- Laboratorio de Células Mieloides, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain
| | - Catherine Béchade
- INSERM UMR-S839, 75005 Paris, France.,Sorbonne University and UPMC University Paris, 75005 Paris, France; and.,Institut du Fer à Moulin, 75005 Paris, France
| | - Luc Maroteaux
- INSERM UMR-S839, 75005 Paris, France.,Sorbonne University and UPMC University Paris, 75005 Paris, France; and.,Institut du Fer à Moulin, 75005 Paris, France
| | - Miguel A Vega
- Laboratorio de Células Mieloides, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain
| | - Ángel L Corbí
- Laboratorio de Células Mieloides, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain;
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Schernthaner-Reiter MH, Trivellin G, Stratakis CA. Chaperones, somatotroph tumors and the cyclic AMP (cAMP)-dependent protein kinase (PKA) pathway. Mol Cell Endocrinol 2020; 499:110607. [PMID: 31586652 DOI: 10.1016/j.mce.2019.110607] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/28/2019] [Accepted: 09/30/2019] [Indexed: 02/08/2023]
Abstract
The cAMP-PKA pathway plays an essential role in the pituitary gland, governing cell differentiation and survival, and maintenance of endocrine function. Somatotroph growth hormone transcription and release as well as cell proliferation are regulated by the cAMP-PKA pathway; cAMP-PKA pathway abnormalities are frequently detected in sporadic as well as in hereditary somatotroph tumors and more rarely in other pituitary tumors. Inactivating variants of the aryl hydrocarbon receptor-interacting protein (AIP)-coding gene are the genetic cause of a subset of familial isolated pituitary adenomas (FIPA). Multiple functional links between the co-chaperone AIP and the cAMP-PKA pathway have been described. This review explores the role of chaperones including AIP in normal pituitary function as well as in somatotroph tumors, and their interaction with the cAMP-PKA pathway.
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Affiliation(s)
| | - Giampaolo Trivellin
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, USA
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, USA
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8
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Schernthaner-Reiter MH, Trivellin G, Stratakis CA. Interaction of AIP with protein kinase A (cAMP-dependent protein kinase). Hum Mol Genet 2019; 27:2604-2613. [PMID: 29726992 DOI: 10.1093/hmg/ddy166] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/29/2018] [Accepted: 05/01/2018] [Indexed: 01/07/2023] Open
Abstract
Germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene cause mostly somatotropinomas and/or prolactinomas in a subset of familial isolated pituitary adenomas (FIPA). AIP has been shown to interact with phosphodiesterases (PDEs) and G proteins, suggesting a link to the cyclic AMP (cAMP)-dependent protein kinase (PKA) pathway. Upregulation of PKA is seen in sporadic somatotropinomas that carry GNAS mutations, and those in Carney complex that are due to PRKAR1A mutations. To elucidate the mechanism of AIP-dependent pituitary tumorigenesis, we studied potential functional and physical interactions of AIP with PKA's main subunits PRKAR1A (R1α) and PRKACA (Cα). We found that AIP physically interacts with both R1α and Cα; this interaction is enhanced when all three components are present, but maintained during Cα-R1α dissociation by PKA activation, indicating that AIP binds Cα/R1α both in complex and separately. The interaction between AIP and R1α/Cα is reduced when the frequent AIP pathogenic mutation p.R304* is present. AIP protein levels are regulated both by translation and the ubiquitin/proteasome pathway and Cα stabilizes both AIP and R1α protein levels. AIP reduction by siRNA leads to an increase of PKA activity, which is disproportionately enhanced during PDE4-inhibition. We show that AIP interacts with the PKA pathway on multiple levels, including a physical interaction with both the main regulatory (R1α) and catalytic (Cα) PKA subunits and a functional interaction with PDE4-dependent PKA activation. These findings provide novel insights on the mechanisms of AIP-dependent pituitary tumorigenesis.
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Affiliation(s)
- Marie Helene Schernthaner-Reiter
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Giampaolo Trivellin
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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Ishihara Y, Kado SY, Hoeper C, Harel S, Vogel CFA. Role of NF-kB RelB in Aryl Hydrocarbon Receptor-Mediated Ligand Specific Effects. Int J Mol Sci 2019; 20:E2652. [PMID: 31151139 PMCID: PMC6600526 DOI: 10.3390/ijms20112652] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 05/24/2019] [Accepted: 05/26/2019] [Indexed: 01/21/2023] Open
Abstract
Here, we investigate the role of RelB in the regulation of genes which were identified to be induced in an aryl hydrocarbon receptor (AhR)-dependent manner and critically involved in regulation of immune responses. We analyzed the expression of genes of the AhR gene battery, cytokines, and immune regulatory enzymes in bone marrow-derived macrophages (BMM) and thymus of B6 wildtype (wt) mice and RelB knockout (RelB-/-) mice after treatment with various AhR ligands. The 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced expression of indoleamine 2,3-dioxygenase 1 (IDO1) and IDO2 was significantly repressed in thymus of RelB-/- mice but not in BMM derived from RelB-/- mice. Interestingly, the induced and basal expression of the cytokines interleukin (IL)-17A, IL-22, and CCL20 required the functional expression of RelB. The RelB-dependent expression of CCL20 was induced by the AhR ligands TCDD and 6-formylindolo[3,2-b]carbazole (FICZ), whereas indole-3-carbinol (I3C) suppressed CCL20 in lipopolysaccharide (LPS)-activated wt BMM. The LPS-induced expression of IL-6 and IL-10 was enhanced by TCDD and FICZ, whereas I3C significantly suppressed these cytokines in BMM. The exposure to FICZ led to higher increases of IL-17A and IL-22 mRNA compared to the effect of TCDD or I3C in thymus of wt mice. On the other hand, TCDD was the strongest inducer of CYP1A1, AhR Repressor (AhRR), and IDO2. In summary, these findings provide evidence for the important role of RelB in the transcriptional regulation of cytokines and enzymes induced by AhR ligands.
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Affiliation(s)
- Yasuhiro Ishihara
- Center for Health and the Environment, University of California, One Shields Avenue, Davis, CA 95616, USA.
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima 739-8521, Japan.
| | - Sarah Y Kado
- Center for Health and the Environment, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | - Christiane Hoeper
- Center for Health and the Environment, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | - Shelly Harel
- Center for Health and the Environment, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | - Christoph F A Vogel
- Center for Health and the Environment, University of California, One Shields Avenue, Davis, CA 95616, USA.
- Department of Environmental Toxicology, University of California, One Shields Avenue, Davis, CA 95616, USA.
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10
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Scott CH, Cha KM, Ngai J, Jiang C, Cheng K, Stokes RA, Ho KWK, George J, Gonzalez FJ, Gunton JE. Hepatic Aryl hydrocarbon Receptor Nuclear Translocator (ARNT) regulates metabolism in mice. PLoS One 2017; 12:e0186543. [PMID: 29190746 PMCID: PMC5708799 DOI: 10.1371/journal.pone.0186543] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 09/11/2017] [Indexed: 01/09/2023] Open
Abstract
Background & aims Aryl hydrocarbon Receptor Nuclear Translocator (ARNT) and its partners hypoxia-inducible factors (HIF)-1α and HIF-2α are candidate factors for the well-known link between the liver, metabolic dysfunction and elevation in circulating lipids and glucose. Methods: Hepatocyte-specific ARNT-null (LARNT), HIF-1α-null (LHIF1α) and HIF-2α-null (LHIF2α) mice were created. Results LARNT mice had increased fasting glucose, impaired glucose tolerance, increased glucose production, raised post-prandial serum triglycerides (TG) and markedly lower hepatic ATP versus littermate controls. There was increased expression of G6Pase, Chrebp, Fas and Scd-1 mRNAs in LARNT animals. Surprisingly, LHIF1α and LHIF2α mice exhibited no alterations in any metabolic parameter assessed. Conclusions These results provide convincing evidence that reduced hepatic ARNT can contribute to inappropriate hepatic glucose production and post-prandial dyslipidaemia. Hepatic ARNT may be a novel therapeutic target for improving post-prandial hypertriglyceridemia and glucose homeostasis.
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Affiliation(s)
- Christopher H. Scott
- The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW. Australia
- Diabetes and Transcription Factors Group, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Kuan-Minn Cha
- The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW. Australia
- Diabetes and Transcription Factors Group, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Jason Ngai
- Diabetes and Transcription Factors Group, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Changtao Jiang
- Laboratory of Metabolism, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Kim Cheng
- The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW. Australia
- Diabetes and Transcription Factors Group, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Rebecca A. Stokes
- The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW. Australia
- Diabetes and Transcription Factors Group, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Kenneth W. K. Ho
- Diabetes and Transcription Factors Group, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Jacob George
- The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW. Australia
- Storr Liver Unit, Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW. Australia
| | - Frank J. Gonzalez
- Laboratory of Metabolism, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Jenny E. Gunton
- The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW. Australia
- Diabetes and Transcription Factors Group, Garvan Institute of Medical Research, Sydney, NSW, Australia
- St. Vincent’s Clinical School, University of NSW, Sydney, NSW, Australia
- Department of Diabetes and Endocrinology, Westmead Hospital, Sydney, NSW Australia
- * E-mail:
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Benzo(a)pyrene triggers desensitization of β2-adrenergic pathway. Sci Rep 2017; 7:3262. [PMID: 28607424 PMCID: PMC5468268 DOI: 10.1038/s41598-017-03646-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 05/02/2017] [Indexed: 12/14/2022] Open
Abstract
Exposure to environmental polycyclic aromatic hydrocarbons (PAHs), such as benzo(a)pyrene (B(a)P), has been linked to several health-threatening risks. PAHs were also shown to hinder adrenergic receptor (ADR) responses. As we previously demonstrated that B(a)P can directly interact with the β2ADR, we investigated here whether B(a)P could decrease β2ADR responsiveness by triggering receptor desensitization phenomena. We firstly showed that exposure to B(a)P reduced β2ADR-mediated epinephrine-induced induction of NR4A gene mRNAs and of intracellular cAMP. Analysis of β2ADR protein expression demonstrated that B(a)P rapidly decreased membrane expression of β2ADR with a subsequent degradation of receptor protein. B(a)P exposure concomitantly rapidly increased the β2ADR mRNA levels. The use of the β-blockers, propranolol and ICI 118.551, demonstrated the involvement of β2ADR itself in this increase. However, sustained exposure to B(a)P induced a diminution of β2ADR mRNA steady-state as a result of the acceleration of its degradation. Together, these results show that, beside the well-known activation of the aryl hydrocarbon receptor, PAH deleterious effects may involve the dysfunction of adrenergic responses through, in part, the desensitization of β2ADR. This may be taken in consideration when β2-agonists/antagonists are administered in patients exposed to important concentrations of PAHs, e.g. in cigarette smokers.
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12
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Xue Z, Li D, Yu W, Zhang Q, Hou X, He Y, Kou X. Mechanisms and therapeutic prospects of polyphenols as modulators of the aryl hydrocarbon receptor. Food Funct 2017; 8:1414-1437. [DOI: 10.1039/c6fo01810f] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Polyphenolic AhR modulators displayed concentration-, XRE-, gene-, species- and cell-specific agonistic/antagonistic activity.
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Affiliation(s)
- Zhaohui Xue
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Dan Li
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Wancong Yu
- Medical Plant Laboratory
- Tianjin Research Center of Agricultural Biotechnology
- Tianjin 3000381
- China
| | - Qian Zhang
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Xiaonan Hou
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Yulong He
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Xiaohong Kou
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
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13
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Tomblin JK, Arthur S, Primerano DA, Chaudhry AR, Fan J, Denvir J, Salisbury TB. Aryl hydrocarbon receptor (AHR) regulation of L-Type Amino Acid Transporter 1 (LAT-1) expression in MCF-7 and MDA-MB-231 breast cancer cells. Biochem Pharmacol 2016; 106:94-103. [PMID: 26944194 DOI: 10.1016/j.bcp.2016.02.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 02/29/2016] [Indexed: 02/06/2023]
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that is regulated by environmental toxicants that function as AHR agonists such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). L-Type Amino Acid Transporter 1 (LAT1) is a leucine transporter that is overexpressed in cancer. The regulation of LAT1 by AHR in MCF-7 and MDA-MB-231 breast cancer cells (BCCs) was investigated in this report. Ingenuity pathway analysis (IPA) revealed a significant association between TCDD-regulated genes (TRGs) and molecular transport. Overlapping the TCDD-RNA-Seq dataset obtained in this study with a published TCDD-ChIP-seq dataset identified LAT1 as a primary target of AHR-dependent TCDD induction. Short interfering RNA (siRNA)-directed knockdown of AHR confirmed that TCDD-stimulated increases in LAT1 mRNA and protein required AHR expression. TCDD-stimulated increases in LAT1 mRNA were also inhibited by the AHR antagonist CH-223191. Upregulation of LAT1 by TCDD coincided with increases in leucine uptake by MCF-7 cells in response to TCDD. Chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR) assays revealed increases in AHR, AHR nuclear translocator (ARNT) and p300 binding and histone H3 acetylation at an AHR binding site in the LAT1 gene in response to TCDD. In MCF-7 and MDA-MB-231 cells, endogenous levels of LAT1 mRNA and protein were reduced in response to knockdown of AHR expression. Knockdown experiments demonstrated that proliferation of MCF-7 and MDA-MB-231 cells is dependent on both LAT1 and AHR. Collectively, these findings confirm the dependence of cancer cells on leucine uptake and establish a mechanism for extrinsic and intrinsic regulation of LAT1 by AHR.
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Affiliation(s)
- Justin K Tomblin
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA.
| | - Subha Arthur
- Department of Clinical & Translational Science, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA.
| | - Donald A Primerano
- Department of Biochemistry and Microbiology, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA.
| | - Ateeq R Chaudhry
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA.
| | - Jun Fan
- Department of Biochemistry and Microbiology, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA.
| | - James Denvir
- Department of Biochemistry and Microbiology, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA.
| | - Travis B Salisbury
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA.
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14
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Feng Y, Tian J, Krylova I, Xu T, Xie HQ, Guo TL, Zhao B. Chronic TCDD exposure results in the dysregulation of gene expression in splenic B-lymphocytes and in the impairments in T-cell and B-cell differentiation in mouse model. J Environ Sci (China) 2016; 39:218-227. [PMID: 26899660 DOI: 10.1016/j.jes.2015.11.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 11/01/2015] [Accepted: 11/02/2015] [Indexed: 06/05/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exposure in humans is associated with marked immune suppressions and increased incidence of lymphoblastic diseases. To elucidate mechanisms of impairments in humoral immune responses, we used a murine model. Following a 20-week administration of low doses of TCDD, we observed severely reduced antibody titers, dramatically decreased number of splenic Th1 and Th2 cells and an increase in CD19(+) B cells. Transcriptional profiling of CD19(+) B cells showed that markers of pre-B cells were significantly elevated, indicating delayed B cell maturation. These changes in B cells were accompanied by decreases of T helper cell numbers and reduced IgM and IgG titers. A transcriptome analysis of splenic B cells followed by Ingenuity Pathway Analysis (IPA) revealed a set of differentially expressed genes known to play roles in tumorigenesis, cell-proliferation and cell-migration. The most up-regulated transcript gene was Eph receptor A2 (EphA2), a known oncogene, and the most down-regulated transcript was ZBTB16 that codes for a negative transcriptional regulator important in epigenetic chromatin remodeling. IPA identified cAMP-responsive element modulator (CREM) and cAMP-responsive element binding protein 1 (CREB1) as top upstream regulators. Consistently, a MAPPER promoter database analysis showed that all top dysregulated genes had CREM and/or CREB1 binding sites in their promoter regions. In summary, our data showed that chronic TCDD exposure in mice caused suppressed humoral immunity accompanied with profound dysregulation of gene expression in splenic B-lymphocytes, likely through cAMP-dependent pathways. This dysregulation resulted in impairments in T-cell and B-cell differentiation and activation of the tumorigenic transcription program.
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Affiliation(s)
- Yu Feng
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Jijing Tian
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | | | - Tuan Xu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Heidi Qunhui Xie
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Tai L Guo
- Department of Veterinary Biosciences and Diagnostic Imaging, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-7382, USA
| | - Bin Zhao
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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15
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Screening a mouse liver gene expression compendium identifies modulators of the aryl hydrocarbon receptor (AhR). Toxicology 2015. [PMID: 26215100 DOI: 10.1016/j.tox.2015.07.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates the biological and toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), dioxin-like compounds (DLC) as well as some drugs and endogenous tryptophan metabolites. Short-term activation of AhR can lead to hepatocellular steatosis, and chronic activation can lead to liver cancer in mice and rats. Analytical approaches were developed to identify biosets in a genomic database in which AhR activity was altered. A set of 63 genes was identified (the AhR gene expression biomarker) that was dependent on AhR for regulation after exposure to TCDD or benzo[a]pyrene and includes the known AhR targets Cyp1a1 and Cyp1b1. A fold-change rank-based test (Running Fisher's test; p-value ≤ 10(-4)) was used to evaluate the similarity between the AhR biomarker and a test set of 37 and 41 biosets positive or negative, respectively for AhR activation. The test resulted in a balanced accuracy of 95%. The rank-based test was used to identify factors that activate or suppress AhR in an annotated mouse liver/mouse primary hepatocyte gene expression database of ∼ 1850 comparisons. In addition to the expected activation of AhR by TCDD and DLC, AhR was activated by AP20189 and phenformin. AhR was suppressed by phenobarbital and 1,4-Bis[2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP) in a constitutive activated receptor (CAR)-dependent manner and pregnenolone-16α-carbonitrile in a pregnane X receptor (PXR)-dependent manner. Inactivation of individual genes in nullizygous models led to AhR activation (Pxr, Ghrhr, Taf10) or suppression (Ahr, Ilst6st, Hnf1a). This study describes a novel screening strategy for identifying factors in mouse liver that perturb AhR in a gene expression compendium.
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16
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Cannavo S, Ferrau F, Ragonese M, Romeo PD, Torre ML, Puglisi S, De Menis E, Arnaldi G, Salpietro C, Cotta OR, Albani A, Ruggeri RM, Trimarchi F. Increased frequency of the rs2066853 variant of aryl hydrocarbon receptor gene in patients with acromegaly. Clin Endocrinol (Oxf) 2014; 81:249-53. [PMID: 24521362 DOI: 10.1111/cen.12424] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 12/03/2013] [Accepted: 02/03/2014] [Indexed: 12/13/2022]
Abstract
CONTEXT Aryl hydrocarbon receptor (AHR) pathway has a key role in cellular detoxification mechanisms and seems implicated in tumorigenesis. Moreover, polymorphisms and mutations of AHR gene have been associated with several human and animal tumours. Although AHR has been found differently expressed in pituitary adenomas, AHR gene mutation status has never been investigated in acromegalic patients. DESIGN In this study, we evaluated patients with apparently sporadic GH-secreting pituitary adenoma for AHR gene variants. PATIENTS AND METHODS Seventy patients with sporadic GH-secreting pituitary adenoma (M = 27, age 59.1 ± 1.6 years) and 157 sex- and age-matched controls were enrolled in the study. In all patients and controls, the exons 1, 2, 3, 5 and 10 of AHR gene were evaluated for nucleotide variants by sequencing analysis. RESULTS The rs2066853 polymorphism was identified in the exon 10 of 18/70 acromegalic patients and 9/157 healthy subjects (25.7 vs. 5.7%, χ(2) = 18.98 P < 0.0001), in homozygosis in one patient and in heterozygosis in the other 17 and in the 9 healthy subjects. Moreover, a heterozygous rs4986826 variant in exon 10 was identified in a patient with heterozygous rs2066853 polymorphism, and in the patient with homozygous rs2066853 variant. This second polymorphism was not detected in the control group. Patients with rs2066853 polymorphism showed increased IGF-1 ULN (P < 0.05) and prevalence of cavernous sinus invasion (P = 0.05), thyroid (P = 0.02), bladder (P = 0.0001) or lymphohematopoietic (P < 0.05) tumours. CONCLUSIONS AHR gene rs2066853 polymorphism is significantly more frequent in acromegalic patients than in healthy subjects and is associated with increased disease aggressivity. Moreover, the rs4986826 variant was detected in few patients with rs2066853 polymorphism, but its role is to be cleared.
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Affiliation(s)
- S Cannavo
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
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17
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Formosa R, Vassallo J. cAMP signalling in the normal and tumorigenic pituitary gland. Mol Cell Endocrinol 2014; 392:37-50. [PMID: 24845420 DOI: 10.1016/j.mce.2014.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/04/2014] [Accepted: 05/05/2014] [Indexed: 01/06/2023]
Abstract
cAMP signalling plays a key role in the normal physiology of the pituitary gland, regulating cellular growth and proliferation, hormone production and release. Deregulation of the cAMP signalling pathway has been reported to be a common occurrence in pituitary tumorigenesis. Several mechanisms have been implicated including somatic mutations, gene-gene interactions and gene-environmental interactions. Somatic mutations in G-proteins and protein kinases directly alter cAMP signalling, while malfunctioning of other signalling pathways such as the Raf/MAPK/ERK, PI3K/Akt/mTOR and Wnt pathways which normally interact with the cAMP pathway may mediate indirect effects on cAMP and varying downstream effectors. The aryl hydrocarbon receptor signalling pathway has been implicated in pituitary tumorigenesis and we review its role in general and specifically in relation to cAMP de-regulation.
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Affiliation(s)
- R Formosa
- Department of Medicine, Faculty of Medicine and Surgery, University of Malta, Level 0, Block A, Mater Dei Hospital, Msida MSD2080, Malta.
| | - J Vassallo
- Department of Medicine, Faculty of Medicine and Surgery, University of Malta, Level 0, Block A, Mater Dei Hospital, Msida MSD2080, Malta.
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18
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Scott C, Bonner J, Min D, Boughton P, Stokes R, Cha KM, Walters SN, Maslowski K, Sierro F, Grey ST, Twigg S, McLennan S, Gunton JE. Reduction of ARNT in myeloid cells causes immune suppression and delayed wound healing. Am J Physiol Cell Physiol 2014; 307:C349-57. [PMID: 24990649 DOI: 10.1152/ajpcell.00306.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Aryl hydrocarbon receptor nuclear translocator (ARNT) is a transcription factor that binds to partners to mediate responses to environmental signals. To investigate its role in the innate immune system, floxed ARNT mice were bred with lysozyme M-Cre recombinase animals to generate lysozyme M-ARNT (LAR) mice with reduced ARNT expression. Myeloid cells of LAR mice had altered mRNA expression and delayed wound healing. Interestingly, when the animals were rendered diabetic, the difference in wound healing between the LAR mice and their littermate controls was no longer present, suggesting that decreased myeloid cell ARNT function may be an important factor in impaired wound healing in diabetes. Deferoxamine (DFO) improves wound healing by increasing hypoxia-inducible factors, which require ARNT for function. DFO was not effective in wounds of LAR mice, again suggesting that myeloid cells are important for normal wound healing and for the full benefit of DFO. These findings suggest that myeloid ARNT is important for immune function and wound healing. Increasing ARNT and, more specifically, myeloid ARNT may be a therapeutic strategy to improve wound healing.
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Affiliation(s)
- Christopher Scott
- Diabetes and Transcription Factors Group, Department of Immunology and Inflammation, Garvan Institute of Medical Research, Sydney, New South Wales, Australia; Faculty of Medicine, University of Sydney, Sydney, New South Wales, Australia
| | - James Bonner
- Department of Endocrinology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - Danqing Min
- Department of Endocrinology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - Philip Boughton
- St. George Clinical School, St. George Hospital, Kogarah, New South Wales, Australia; Department of Biomedical Engineering, University of Sydney, Sydney, New South Wales, Australia
| | - Rebecca Stokes
- Diabetes and Transcription Factors Group, Department of Immunology and Inflammation, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Kuan Minn Cha
- Diabetes and Transcription Factors Group, Department of Immunology and Inflammation, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Stacey N Walters
- Department of Immunology and Inflammation, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Kendle Maslowski
- Department of Biochemistry, University of Lausanne, Lausanne, Switzerland
| | - Frederic Sierro
- Liver Immunology, Centenary Institute, Sydney, New South Wales, Australia
| | - Shane T Grey
- Department of Immunology and Inflammation, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Stephen Twigg
- Faculty of Medicine, University of Sydney, Sydney, New South Wales, Australia; Department of Endocrinology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - Susan McLennan
- Faculty of Medicine, University of Sydney, Sydney, New South Wales, Australia; Department of Endocrinology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - Jenny E Gunton
- Diabetes and Transcription Factors Group, Department of Immunology and Inflammation, Garvan Institute of Medical Research, Sydney, New South Wales, Australia; Faculty of Medicine, University of Sydney, Sydney, New South Wales, Australia; St. Vincent's Clinical School, University of New South Wales, Sydney, New South Wales, Australia; and Department of Diabetes and Endocrinology, Westmead Hospital, Sydney, New South Wales, Australia
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Budinsky RA, Schrenk D, Simon T, Van den Berg M, Reichard JF, Silkworth JB, Aylward LL, Brix A, Gasiewicz T, Kaminski N, Perdew G, Starr TB, Walker NJ, Rowlands JC. Mode of action and dose–response framework analysis for receptor-mediated toxicity: The aryl hydrocarbon receptor as a case study. Crit Rev Toxicol 2013; 44:83-119. [DOI: 10.3109/10408444.2013.835787] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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20
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Anderson G, Maes M. Neurodegeneration in Parkinson's disease: interactions of oxidative stress, tryptophan catabolites and depression with mitochondria and sirtuins. Mol Neurobiol 2013; 49:771-83. [PMID: 24085563 DOI: 10.1007/s12035-013-8554-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 09/19/2013] [Indexed: 11/29/2022]
Abstract
The biological underpinnings to the etiology and course of neurodegeneration in Parkinson's disease are an area of extensive research that has yet to produce an early biological marker or disease-slowing or preventative treatment. Recent conceptualizations of Parkinson's disease have integrated immuno-inflammation and oxidative and nitrosative stress occurring in depression, somatization and peripheral inflammation into the course of Parkinson's disease. We review the data showing the importance of immuno-inflammatory processes and oxidative and nitrosative stress in such classically conceived 'comorbidities', suggesting that lifetime, prodromal and concurrent depression and somatization may be intricately involved in the etiology and course of Parkinson's disease, rather than psychiatric comorbidities. This produces a longer term developmental perspective of Parkinson's disease, which incorporates tryptophan catabolites (TRYCATs), lipid peroxidation, sirtuins, cyclic adenosine monophosphate, aryl hydrocarbon receptor, and circadian genes. This integrates wider bodies of data pertaining to neuronal loss in Parkinson's disease, emphasizing how these interact with susceptibility genes to drive changes in mitochondria, blood-brain barrier permeability and intercellular signalling. We review this data here in the context of neurodegeneration in Parkinson's disease and to the future directions indicated for slowing disease progression.
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21
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Anderson G, Beischlag TV, Vinciguerra M, Mazzoccoli G. The circadian clock circuitry and the AHR signaling pathway in physiology and pathology. Biochem Pharmacol 2013; 85:1405-16. [PMID: 23438471 DOI: 10.1016/j.bcp.2013.02.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 02/14/2013] [Accepted: 02/14/2013] [Indexed: 12/14/2022]
Abstract
Life forms populating the Earth must face environmental challenges to assure individual and species survival. The strategies predisposed to maintain organismal homeostasis and grant selective advantage rely on anticipatory phenomena facing periodic modifications, and compensatory phenomena facing unpredictable changes. Biological processes bringing about these responses are respectively driven by the circadian timing system, a complex of biological oscillators entrained to the environmental light/dark cycle, and by regulatory and metabolic networks that precisely direct the body's adjustments to variations of external conditions and internal milieu. A critical role in organismal homeostatic functions is played by the aryl hydrocarbon receptor (AHR) complex, which senses environmental and endogenous compounds, influences metabolic responses controlling phase I/II gene expression, and modulates vital phenomena such as development, inflammation and adaptive immunity. A physiological cross-talk between circadian and AHR signaling pathways has been evidenced. The alteration of AHR signaling pathway deriving from genetic damage with polymorphisms or mutations, or produced by exogenous or endogenous AHR activation, and chronodisruption caused by mismatch between the body's internal clock and geophysical time/social schedules, are capable of triggering pathological mechanisms involved in metabolic, immune-related and neoplastic diseases. On the other hand, the molecular components of the circadian clock circuitry and AHR signaling pathway may represent useful tools for preventive interventions and valuable targets of therapeutic approaches.
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Affiliation(s)
- George Anderson
- Clinical Research Centre/Communications, Glasgow, United Kingdom
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22
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Kostyuk V, Potapovich A, Stancato A, De Luca C, Lulli D, Pastore S, Korkina L. Photo-oxidation products of skin surface squalene mediate metabolic and inflammatory responses to solar UV in human keratinocytes. PLoS One 2012; 7:e44472. [PMID: 22952984 PMCID: PMC3431355 DOI: 10.1371/journal.pone.0044472] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 08/08/2012] [Indexed: 12/31/2022] Open
Abstract
The study aimed to identify endogenous lipid mediators of metabolic and inflammatory responses of human keratinocytes to solar UV irradiation. Physiologically relevant doses of solar simulated UVA+UVB were applied to human skin surface lipids (SSL) or to primary cultures of normal human epidermal keratinocytes (NHEK). The decay of photo-sensitive lipid-soluble components, alpha-tocopherol, squalene (Sq), and cholesterol in SSL was analysed and products of squalene photo-oxidation (SqPx) were quantitatively isolated from irradiated SSL. When administered directly to NHEK, low-dose solar UVA+UVB induced time-dependent inflammatory and metabolic responses. To mimic UVA+UVB action, NHEK were exposed to intact or photo-oxidised SSL, Sq or SqPx, 4-hydroxy-2-nonenal (4-HNE), and the product of tryptophan photo-oxidation 6-formylindolo[3,2-b]carbazole (FICZ). FICZ activated exclusively metabolic responses characteristic for UV, i.e. the aryl hydrocarbon receptor (AhR) machinery and downstream CYP1A1/CYP1B1 gene expression, while 4-HNE slightly stimulated inflammatory UV markers IL-6, COX-2, and iNOS genes. On contrast, SqPx induced the majority of metabolic and inflammatory responses characteristic for UVA+UVB, acting via AhR, EGFR, and G-protein-coupled arachidonic acid receptor (G2A).
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Affiliation(s)
- Vladimir Kostyuk
- Laboratory of Tissue Engineering & Skin Pathophysiology, Istituto Dermopatico dell'Immacolata (IDI IRCCS), Rome, Italy
- Biology Department, Belarus State University, Minsk, Belarus
| | - Alla Potapovich
- Laboratory of Tissue Engineering & Skin Pathophysiology, Istituto Dermopatico dell'Immacolata (IDI IRCCS), Rome, Italy
- Biology Department, Belarus State University, Minsk, Belarus
| | - Andrea Stancato
- Laboratory of Tissue Engineering & Skin Pathophysiology, Istituto Dermopatico dell'Immacolata (IDI IRCCS), Rome, Italy
| | - Chiara De Luca
- Laboratory of Tissue Engineering & Skin Pathophysiology, Istituto Dermopatico dell'Immacolata (IDI IRCCS), Rome, Italy
| | - Daniela Lulli
- Laboratory of Tissue Engineering & Skin Pathophysiology, Istituto Dermopatico dell'Immacolata (IDI IRCCS), Rome, Italy
| | - Saveria Pastore
- Laboratory of Tissue Engineering & Skin Pathophysiology, Istituto Dermopatico dell'Immacolata (IDI IRCCS), Rome, Italy
| | - Liudmila Korkina
- Laboratory of Tissue Engineering & Skin Pathophysiology, Istituto Dermopatico dell'Immacolata (IDI IRCCS), Rome, Italy
- * E-mail:
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23
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Wang D, Wang H. Oxazaphosphorine bioactivation and detoxification The role of xenobiotic receptors. Acta Pharm Sin B 2012; 2. [PMID: 24349963 DOI: 10.1016/j.apsb.2012.02.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Oxazaphosphorines, with the most representative members including cyclophosphamide, ifosfamide, and trofosfamide, constitute a class of alkylating agents that have a broad spectrum of anticancer activity against many malignant ailments including both solid tumors such as breast cancer and hematological malignancies such as leukemia and lymphoma. Most oxazaphosphorines are prodrugs that require hepatic cytochrome P450 enzymes to generate active alkylating moieties before manifesting their chemotherapeutic effects. Meanwhile, oxazaphosphorines can also be transformed into non-therapeutic byproducts by various drug-metabolizing enzymes. Clinically, oxazaphosphorines are often administered in combination with other chemotherapeutics in adjuvant treatments. As such, the therapeutic efficacy, off-target toxicity, and unintentional drug-drug interactions of oxazaphosphorines have been long-lasting clinical concerns and heightened focuses of scientific literatures. Recent evidence suggests that xenobiotic receptors may play important roles in regulating the metabolism and clearance of oxazaphosphorines. Drugs as modulators of xenobiotic receptors can affect the therapeutic efficacy, cytotoxicity, and pharmacokinetics of coadministered oxazaphosphorines, providing a new molecular mechanism of drug-drug interactions. Here, we review current advances regarding the influence of xenobiotic receptors, particularly, the constitutive androstane receptor, the pregnane X receptor and the aryl hydrocarbon receptor, on the bioactivation and detoxification of oxazaphosphorines, with a focus on cyclophosphamide and ifosfamide.
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24
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Mayati A, Levoin N, Paris H, N'Diaye M, Courtois A, Uriac P, Lagadic-Gossmann D, Fardel O, Le Ferrec E. Induction of intracellular calcium concentration by environmental benzo(a)pyrene involves a β2-adrenergic receptor/adenylyl cyclase/Epac-1/inositol 1,4,5-trisphosphate pathway in endothelial cells. J Biol Chem 2011; 287:4041-52. [PMID: 22167199 DOI: 10.1074/jbc.m111.319970] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene (B(a)P) are widely distributed environmental contaminants, known as potent ligands of the aryl hydrocarbon receptor (AhR). These chemicals trigger an early and transient increase of intracellular calcium concentration ([Ca(2+)](i)), required for AhR-related effects of PAHs. The mechanisms involved in this calcium mobilization were investigated in the present study. We demonstrated that B(a)P-mediated [Ca(2+)](i) induction was prevented in endothelial HMEC-1 cells by counteracting β2-adrenoreceptor (β2ADR) activity using pharmacological antagonists, anti-β2ADR antibodies, or siRNA-mediated knockdown of β2ADR expression; by contrast, it was strongly potentiated by β2ADR overexpression in human kidney HEK293 cells. B(a)P was shown, moreover, to directly bind to β2ADR, as assessed by in vitro binding assays and molecular modeling. Pharmacological inhibition and/or siRNA-mediated silencing of various signaling actors acting downstream of β2ADR in a sequential manner, such as G protein, adenylyl cyclase, Epac-1 protein, and inositol 1,4,5-trisphosphate (IP(3))/IP(3) receptor, were next demonstrated to prevent B(a)P-induced calcium signal. Inhibition or knockdown of these signaling elements, as well as the use of chemical β-blockers, were finally shown to counteract B(a)P-mediated induction of cytochrome P-450 1B1, a prototypical AhR target gene. Taken together, our results show that B(a)P binds directly to β2ADR and consequently utilizes β2ADR machinery to mobilize [Ca(2+)](i), through activation of a G protein/adenylyl cyclase/cAMP/Epac-1/IP(3) pathway. This β2ADR-dependent signaling pathway activated by PAHs may likely be crucial for PAH-mediated up-regulation of AhR target genes, thus suggesting a contribution of β2ADR to the health-threatening effects of these environmental pollutants.
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Affiliation(s)
- Abdullah Mayati
- INSERM U1085/IRSET, IFR140, Université de Rennes 1, 2 Avenue du Pr. L. Bernard, Rennes 35043, France
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25
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Abstract
Germline mutations in the aryl hydrocarbon receptor-interacting protein gene (AIP) predispose to young-onset pituitary tumours, most often to GH- or prolactin-secreting adenomas, and most of these patients belong to familial isolated pituitary adenoma families. The molecular pathway initiated by the loss-of-function AIP mutations leading to pituitary tumour formation is unknown. AIP, a co-chaperone of heat-shock protein 90 and various nuclear receptors, belongs to the family of tetratricopeptide repeat (TPR)-containing proteins. It has three antiparallel α-helix motifs (TPR domains) that mediate the interaction of AIP with most of its partners. In this review, we summarise the known interactions of AIP described so far. The identification of AIP partners and the understanding of how AIP interacts with these proteins might help to explain the specific phenotype of the families with heterozygous AIP mutations, to gain deeper insight into the pathological process of pituitary tumour formation and to identify novel drug targets.
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Affiliation(s)
- Giampaolo Trivellin
- Department of Endocrinology, Bart's and the London School of Medicine, Queen Mary University of London, London EC1M 6BQ, UK
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Kurki MI, Paananen J, Storvik M, Ylä-Herttuala S, Jääskeläinen JE, von Und Zu Fraunberg M, Wong G, Pehkonen P. TAFFEL: Independent Enrichment Analysis of gene sets. BMC Bioinformatics 2011; 12:171. [PMID: 21592412 PMCID: PMC3120704 DOI: 10.1186/1471-2105-12-171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 05/19/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A major challenge in genomic research is identifying significant biological processes and generating new hypotheses from large gene sets. Gene sets often consist of multiple separate biological pathways, controlled by distinct regulatory mechanisms. Many of these pathways and the associated regulatory mechanisms might be obscured by a large number of other significant processes and thus not identified as significant by standard gene set enrichment analysis tools. RESULTS We present a novel method called Independent Enrichment Analysis (IEA) and software TAFFEL that eases the task by clustering genes to subgroups using Gene Ontology categories and transcription regulators. IEA indicates transcriptional regulators putatively controlling biological functions in studied condition. CONCLUSIONS We demonstrate that the developed method and TAFFEL tool give new insight to the analysis of differentially expressed genes and can generate novel hypotheses. Our comparison to other popular methods showed that the IEA method implemented in TAFFEL can find important biological phenomena, which are not reported by other methods.
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Affiliation(s)
- Mitja I Kurki
- Department of Biosciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
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27
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Curtis LR, Garzon CB, Arkoosh M, Collier T, Myers MS, Buzitis J, Hahn ME. Reduced cytochrome P4501A activity and recovery from oxidative stress during subchronic benzo[a]pyrene and benzo[e]pyrene treatment of rainbow trout. Toxicol Appl Pharmacol 2011; 254:1-7. [PMID: 21550360 DOI: 10.1016/j.taap.2011.04.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 04/08/2011] [Accepted: 04/20/2011] [Indexed: 02/02/2023]
Abstract
This study assessed the role of aryl hydrocarbon receptor (AHR) affinity, and cytochrome P4501A (CYP1A) protein and activity in polyaromatic hydrocarbon (PAH)-induced oxidative stress. In the 1-100nM concentration range benzo[a]pyrene (BaP) but not benzo[e]pyrene (BeP) competitively displaced 2nM [(3)H]2, 3, 7, 8-tetrachloro-dibenzo-p-dioxin from rainbow trout AHR2α. Based on appearance of fluorescent aromatic compounds in bile over 3, 7, 14, 28 or 50days of feeding 3μg of BaP or BeP/g fish/day, rainbow trout liver readily excreted these polyaromatic hydrocarbons (PAHs) and their metabolites at near steady state rates. CYP1A proteins catalyzed more than 98% of ethoxyresorufin-O-deethylase (EROD) activity in rainbow trout hepatic microsomes. EROD activity of hepatic microsomes initially increased and then decreased to control activities after 50days of feeding both PAHs. Immunohistochemistry of liver confirmed CYP1A protein increased in fish fed both PAHs after 3days and remained elevated for up to 28days. Neither BaP nor BeP increased hepatic DNA adduct concentrations at any time up to 50days of feeding these PAHs. Comet assays of blood cells demonstrated marked DNA damage after 14days of feeding both PAHs that was not significant after 50days. There was a strong positive correlation between hepatic EROD activity and DNA damage in blood cells over time for both PAHs. Neither CYP1A protein nor 3-nitrotyrosine (a biomarker for oxidative stress) immunostaining in trunk kidney were significantly altered by BaP or BeP after 3, 7, 14, or 28days. There was no clear association between AHR2α affinity and BaP and BeP-induced oxidative stress.
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Affiliation(s)
- Lawrence R Curtis
- Oregon State University, Department of Environmental and Molecular Toxicology, Corvallis, OR, USA.
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Gilot D, Le Meur N, Giudicelli F, Le Vée M, Lagadic-Gossmann D, Théret N, Fardel O. RNAi-based screening identifies kinases interfering with dioxin-mediated up-regulation of CYP1A1 activity. PLoS One 2011; 6:e18261. [PMID: 21479225 PMCID: PMC3066211 DOI: 10.1371/journal.pone.0018261] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 02/23/2011] [Indexed: 11/18/2022] Open
Abstract
Background The aryl hydrocarbon receptor (AhR) is a transcription factor activated by several environmental pollutants, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and involved in carcinogenesis and various physiological processes, including immune response and endocrine functions. Characterization of kinases-related AhR transduction pathway remains an important purpose. Results We performed a kinome-wide siRNA screen in human mammary MCF-7 cells to identify non redundant protein kinases implicated in the up-regulation of cytochrome P-450 (CYP) 1A1 activity, an AhR referent target, in response to TCDD exposure. To this aim, we monitored CYP1A1-related ethoxyresorufin-O-deethylase (EROD) activity and quantified cell density. This normalization was crucial since it allowed us to focus only on siRNA affecting EROD activity and discard siRNA affecting cell density. Analyses of the cell density data allowed us to identify several hits already well-characterized as effectors of the cell cycle and original hits. Collectively, these data fully validated the protocol and the siRNA library. Next, 22 novel candidates were identified as kinases potentially implicated in the up-regulation of CYP1A1 in response to TCDD, without alteration of cell survival or cell proliferation. The siRNA library screen gave a limited number of hits (approximately 3%). Interestingly, four of them are able to bind calmodulin among which the IP3 kinase A (ITPKA) and pregnancy up-regulated non-ubiquitously expressed CaM kinase (PNCK, also named CaMKIβ). Remarkably, for both proteins, their kinase activity depends on the calmodulin binding. Involvement of ITPKA and PNCK in TCDD-mediated CYP1A1 up-regulation was further validated by screening-independent expression knock-down. PNCK was finally shown to regulate activation of CaMKIα, a CaMKI isoform previously reported to interplay with the AhR pathway. Conclusions These data fully support a role for both IP3-related kinase and CaMK isoforms in the AhR signaling cascade. More generally, this study also highlights the interest of large scale loss-of-function screens for characterizing the molecular mechanism of action of environmental contaminants.
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Affiliation(s)
- David Gilot
- EA 4427 Signalisation et Réponse aux Agents Infectieux et Chimiques, Université de Rennes 1, Institut de Recherche Santé, Environnement et Travail, Institut Fédératif de Recherche 140, Rennes, France.
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Chopra M, Schrenk D. Dioxin toxicity, aryl hydrocarbon receptor signaling, and apoptosis-persistent pollutants affect programmed cell death. Crit Rev Toxicol 2011; 41:292-320. [PMID: 21323611 DOI: 10.3109/10408444.2010.524635] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Exogenous ligands of the aryl hydrocarbon receptor (AhR) such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related substances are highly toxic pollutants ubiquitously present in the environment. They cause a variety of toxic effects to different organs and tissues. Among other effects, TCDD exposure to laboratory animals leads to thymus atrophy and immunosuppression on the one hand, and to tumor formation on the other. Apoptosis appears to be involved in both these toxic effects: AhR activation by TCDD was discussed to induce apoptosis of immune cells, leading to the depletion of thymocytes and ultimately immunosuppression. This mechanism could help to explain the highly immunotoxic actions of TCDD but it is nevertheless under debate whether this is the mode of action for immunosuppression by this class of chemical substances. In other cell types, especially liver cells, TCDD inhibits apoptosis induced by genotoxic treatment. In initiation-promotion studies, TCDD was shown to be a potent liver tumor promoter. Among other theories it was hypothesized that TCDD acts as a tumor promoter by preventing initiated cells from undergoing apoptosis. The exact mechanisms of apoptosis inhibition by TCDD are not fully understood, but both in vivo and in vitro studies consistently showed an involvement of the tumor suppressor p53 in this effect. Various strings of evidence have been established linking apoptosis to the detrimental effects of exogenous activation of the AhR. Within this article, studies elucidating the effects of TCDD and related substances on apoptosis signaling, be it inducing or repressing, is to be reviewed.
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Affiliation(s)
- Martin Chopra
- Institute of Food Chemistry and Toxicology, University of Kaiserslautern, Kaiserslautern, Germany
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Vandeva S, Vasilev V, Vroonen L, Naves L, Jaffrain-Rea ML, Daly AF, Zacharieva S, Beckers A. Familial pituitary adenomas. ANNALES D'ENDOCRINOLOGIE 2010; 71:479-85. [PMID: 20961530 DOI: 10.1016/j.ando.2010.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Revised: 08/06/2010] [Accepted: 08/06/2010] [Indexed: 12/31/2022]
Abstract
Pituitary adenomas are benign intracranial neoplasms that present a major clinical concern because of hormonal overproduction or compression symptoms of adjacent structures. Most arise in a sporadic setting with a small percentage developing as a part of familial syndromes such as multiple endocrine neoplasia type 1 (MEN1), Carney complex (CNC), and the recently described familial isolated pituitary adenomas (FIPA) and MEN-4. While the genetic alterations responsible for the formation of sporadic adenomas remain largely unknown, considerable advances have been made in defining culprit genes in these familial syndromes. Mutations in MEN1 and PRKAR1A genes are found in the majority of MEN1 and CNC patients, respectively. About 15% of FIPA kindreds present with mutations of the aryl hydrocarbon receptor-interacting protein (AIP) gene. Mutations in the CDKN1B gene, encoding p27(Kip)¹ were identified in MEN4 cases. Familial tumours appear to differ from their sporadic counterparts not only in genetic basis but also in clinical characteristics. Evidence suggests that, especially in MEN1 and FIPA, they are more aggressive and affect patients at younger age, therefore justifying the importance of early diagnosis. In this review, we summarize the genetic and clinical characteristics of these familial pituitary adenomas.
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Affiliation(s)
- S Vandeva
- Department of Endocrinology, University of Liège, CHU de Liège, Belgium
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31
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Vandeva S, Jaffrain-Rea ML, Daly AF, Tichomirowa M, Zacharieva S, Beckers A. The genetics of pituitary adenomas. Best Pract Res Clin Endocrinol Metab 2010; 24:461-76. [PMID: 20833337 DOI: 10.1016/j.beem.2010.03.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Pituitary adenomas are one of the most frequent intracranial tumors with a prevalence of clinically-apparent tumors close to 1:1000 of the general population. They are clinically significant because of hormone overproduction and/or tumor mass effects in addition to the need for neurosurgery, medical therapies and radiotherapy. The majority of pituitary adenomas have a sporadic origin with recognized genetic mutations seldom being found; somatotropinomas are an exception, presenting frequent somatic GNAS mutations. In this and other phenotypes, tumorigenesis could possibly be explained by altered function of genes implicated in cell cycle regulation, growth factors or their receptors, cell-signaling pathways, specific hormonal factors or other molecules with still unclear mechanisms of action. Genetic changes, such as allelic loss or gene amplification, and epigenetic changes, usually by promoter methylation, have been implicated in abnormal gene expression, but alternative mechanisms may be present. Familial cases of pituitary adenomas represent 5% of all pituitary tumors. MEN1 mutations cause multiple endocrine neoplasia type 1 (MEN1), while the Carney complex (CNC) is characterized by mutations in the protein kinase A regulatory subunit-1alpha (PRKAR1A) gene or changes in a locus at 2p16. Recently, a MEN1-like condition, MEN4, was found to be related to mutations in the CDKN1B gene. The clinical entity of familial isolated pituitary adenomas (FIPA) is characterized by genetic defects in the aryl hydrocarbon receptor interacting protein (AIP) gene in about 15% of all kindreds and 50% of homogenous somatotropinoma families. Identification of familial cases of pituitary adenomas is important as these tumors may be more aggressive than their sporadic counterparts.
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Affiliation(s)
- Silvia Vandeva
- Department of Endocrinology, University of Liège, Domaine Universitaire du Sart-Tilman, 4000 Liège, Belgium
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Stegeman JJ, Goldstone JV, Hahn ME. Perspectives on zebrafish as a model in environmental toxicology. FISH PHYSIOLOGY 2010. [DOI: 10.1016/s1546-5098(10)02910-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Jiang W, Wang L, Zhang W, Coffee R, Fazili IS, Moorthy B. Persistent induction of cytochrome P450 (CYP)1A enzymes by 3-methylcholanthrene in vivo in mice is mediated by sustained transcriptional activation of the corresponding promoters. Biochem Biophys Res Commun 2009; 390:1419-24. [PMID: 19900403 PMCID: PMC2787915 DOI: 10.1016/j.bbrc.2009.11.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 11/04/2009] [Indexed: 11/21/2022]
Abstract
There is significant human exposure to polycyclic aromatic hydrocarbons (PAHs), many of which are potent carcinogens. Cytochrome P450 (CYP)1A enzymes play key roles in the metabolic activation of PAHs to carcinogenic metabolites. We previously showed persistent induction of CYP1A enzymes by 3-methylcholanthrene (MC) in vivo in rodents. In this study, we tested the hypothesis that MC elicits persistent induction of CYP1A1 and 1A2 in vivo by mechanisms entailing sustained transcriptional activation of the corresponding promoters. Adult male wild type (WT) (Cd-1) mice, transgenic mice expressing the human CYP1A1 promoter or the mouse CYP1A2 promoter were treated with the vehicle corn oil (CO) or the carcinogenic PAH, 3-methylcholanthrene (MC), once daily for 4days, and luciferase reporter gene expression was determined at 1, 8, 15, and 22days after MC withdrawal by bioluminescent imaging. Pulmonary and hepatic endogenous expression of CYP1A1 and 1A2 was also determined at the enzymatic, protein, and mRNA levels. The major findings were that MC elicited marked enhancement in the luciferase expression in the CYP1A1-luc as well CYP1A2-luc transgenic mice that was sustained for up to 22days, the magnitude of induction being more pronounced in the CYP1A1-luc mice. MC also caused persistent induction of endogenous CYP1A1 and 1A2 expression in the WT, CYP1A1-luc, and 1A2-luc mice for up to 22days. In conclusion, our results support the hypothesis that MC elicits sustained CYP1A1 and 1A2 expression by sustained transcriptional activation of the corresponding promoters. Thus, these novel transgenic models should be very useful for further understanding of the molecular mechanisms of persistent CYP1A induction, in relation to PAH-mediated carcinogenesis.
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Affiliation(s)
- Weiwu Jiang
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
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