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Kazzaz SA, Tawil J, Harhaj EW. The aryl hydrocarbon receptor-interacting protein in cancer and immunity: Beyond a chaperone protein for the dioxin receptor. J Biol Chem 2024; 300:107157. [PMID: 38479600 PMCID: PMC11002312 DOI: 10.1016/j.jbc.2024.107157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 03/04/2024] [Accepted: 03/06/2024] [Indexed: 04/04/2024] Open
Abstract
The aryl hydrocarbon receptor (AhR)-interacting protein (AIP) is a ubiquitously expressed, immunophilin-like protein best known for its role as a co-chaperone in the AhR-AIP-Hsp90 cytoplasmic complex. In addition to regulating AhR and the xenobiotic response, AIP has been linked to various aspects of cancer and immunity that will be the focus of this review article. Loss-of-function AIP mutations are associated with pituitary adenomas, suggesting that AIP acts as a tumor suppressor in the pituitary gland. However, the tumor suppressor mechanisms of AIP remain unclear, and AIP can exert oncogenic functions in other tissues. While global deletion of AIP in mice yields embryonically lethal cardiac malformations, heterozygote, and tissue-specific conditional AIP knockout mice have revealed various physiological roles of AIP. Emerging studies have established the regulatory roles of AIP in both innate and adaptive immunity. AIP interacts with and inhibits the nuclear translocation of the transcription factor IRF7 to inhibit type I interferon production. AIP also interacts with the CARMA1-BCL10-MALT1 complex in T cells to enhance IKK/NF-κB signaling and T cell activation. Taken together, AIP has diverse functions that vary considerably depending on the client protein, the tissue, and the species.
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Affiliation(s)
- Sarah A Kazzaz
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, USA; Medical Scientist Training Program, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - John Tawil
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Edward W Harhaj
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, USA.
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2
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Rojas BL, Vazquez-Rivera E, Partch CL, Bradfield CA. Dimerization Rules of Mammalian PAS Proteins. J Mol Biol 2024; 436:168406. [PMID: 38109992 PMCID: PMC10922841 DOI: 10.1016/j.jmb.2023.168406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 12/11/2023] [Accepted: 12/13/2023] [Indexed: 12/20/2023]
Abstract
The PAS (PER, ARNT, SIM) protein family plays a vital role in mammalian biology and human disease. This analysis arose from an interest in the signaling mechanics by the Ah receptor (AHR) and the Ah receptor nuclear translocator (ARNT). After more than fifty years by studying this and related mammalian sensor systems, describing the role of PAS domains in signal transduction is still challenging. In this perspective, we attempt to interpret recent studies of mammalian PAS protein structure and consider how this new insight might explain how these domains are employed in human signal transduction with an eye towards developing strategies to target and engineer these molecules for a new generation of therapeutics. Our approach is to integrate our understanding of PAS protein history, cell biology, and molecular biology with recent structural discoveries to help explain the mechanics of mammalian PAS protein signaling. As a learning set, we focus on sequences and crystal structures of mammalian PAS protein dimers that can be visualized using readily available software.
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Affiliation(s)
- Brenda L Rojas
- Molecular and Environmental Toxicology Center, University of Wisconsin at Madison, USA
| | | | - Carrie L Partch
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, USA
| | - Christopher A Bradfield
- Molecular and Environmental Toxicology Center, University of Wisconsin at Madison, USA; McArdle Laboratory for Cancer Research. University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA.
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3
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Kazzaz SA, Shaikh KA, White J, Zhou Q, Powell WH, Harhaj EW. Phosphorylation of aryl hydrocarbon receptor interacting protein by TBK1 negatively regulates IRF7 and the type I interferon response. J Biol Chem 2024; 300:105525. [PMID: 38043800 PMCID: PMC10792245 DOI: 10.1016/j.jbc.2023.105525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 11/09/2023] [Accepted: 11/22/2023] [Indexed: 12/05/2023] Open
Abstract
The innate antiviral response to RNA viruses is initiated by sensing of viral RNAs by RIG-I-like receptors and elicits type I interferon (IFN) production, which stimulates the expression of IFN-stimulated genes that orchestrate the antiviral response to prevent systemic infection. Negative regulation of type I IFN and its master regulator, transcription factor IRF7, is essential to maintain immune homeostasis. We previously demonstrated that AIP (aryl hydrocarbon receptor interacting protein) functions as a negative regulator of the innate antiviral immune response by binding to and sequestering IRF7 in the cytoplasm, thereby preventing IRF7 transcriptional activation and type I IFN production. However, it remains unknown how AIP inhibition of IRF7 is regulated. We show here that the kinase TBK1 phosphorylates AIP and Thr40 serves as the primary target for TBK1 phosphorylation. AIP Thr40 plays critical roles in regulating AIP stability and mediating its interaction with IRF7. The AIP phosphomimetic T40E exhibited increased proteasomal degradation and enhanced interaction with IRF7 compared with wildtype AIP. AIP T40E also blocked IRF7 nuclear translocation, which resulted in reduced type I IFN production and increased viral replication. In sharp contrast, AIP phosphonull mutant T40A had impaired IRF7 binding, and stable expression of AIP T40A in AIP-deficient mouse embryonic fibroblasts elicited a heightened type I IFN response and diminished RNA virus replication. Taken together, these results demonstrate that TBK1-mediated phosphorylation of AIP at Thr40 functions as a molecular switch that enables AIP to interact with and inhibit IRF7, thus preventing overactivation of type I IFN genes by IRF7.
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Affiliation(s)
- Sarah A Kazzaz
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, USA; Medical Scientist Training Program, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Kashif A Shaikh
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Jesse White
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Qinjie Zhou
- Department of Microbiology and Immunology, Miller School of Medicine, The University of Miami, Miami, Florida, USA
| | - Wade H Powell
- Biology Department, Kenyon College, Gambier, Ohio, USA
| | - Edward W Harhaj
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, USA.
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4
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Steidemann MM, Liu J, Bayes K, Castro LP, Ferguson-Miller S, LaPres JJ. Evidence for crosstalk between the aryl hydrocarbon receptor and the translocator protein in mouse lung epithelial cells. Exp Cell Res 2023; 429:113617. [PMID: 37172753 PMCID: PMC10330775 DOI: 10.1016/j.yexcr.2023.113617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 04/07/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023]
Abstract
Cellular homeostasis requires the use of multiple environmental sensors that can respond to a variety of endogenous and exogenous compounds. The aryl hydrocarbon receptor (AHR) is classically known as a transcription factor that induces genes that encode drug metabolizing enzymes when bound to toxicants such as 2,3,7,8-tetrachlorodibenzo-ρ-dioxin (TCDD). The receptor has a growing number of putative endogenous ligands, such as tryptophan, cholesterol, and heme metabolites. Many of these compounds are also linked to the translocator protein (TSPO), an outer mitochondrial membrane protein. Given a portion of the cellular pool of the AHR has also been localized to mitochondria and the overlap in putative ligands, we tested the hypothesis that crosstalk exists between the two proteins. CRISPR/Cas9 was used to create knockouts for AHR and TSPO in a mouse lung epithelial cell line (MLE-12). WT, AHR-/-, and TSPO-/- cells were then exposed to AHR ligand (TCDD), TSPO ligand (PK11195), or both and RNA-seq was performed. More mitochondrial-related genes were altered by loss of both AHR and TSPO than would have been expected just by chance. Some of the genes altered included those that encode for components of the electron transport system and the mitochondrial calcium uniporter. Both proteins altered the activity of the other as AHR loss caused the increase of TSPO at both the mRNA and protein level and loss of TSPO significantly increased the expression of classic AHR battery genes after TCDD treatment. This research provides evidence that AHR and TSPO participate in similar pathways that contribute to mitochondrial homeostasis.
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Affiliation(s)
- Michelle M Steidemann
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Jian Liu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, United States
| | - Kalin Bayes
- Department of Integrative Biology, Michigan State University, East Lansing, MI, 48824, United States
| | - Lizbeth P Castro
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, United States; Department of Cell and Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, United States
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, United States
| | - John J LaPres
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, United States.
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5
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Men S, Wang H. Phenobarbital in Nuclear Receptor Activation: An Update. Drug Metab Dispos 2023; 51:210-218. [PMID: 36351837 PMCID: PMC9900862 DOI: 10.1124/dmd.122.000859] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 11/11/2022] Open
Abstract
Phenobarbital (PB) is a commonly prescribed anti-epileptic drug that can also benefit newborns from hyperbilirubinemia. Being the first drug demonstrating hepatic induction of cytochrome P450 (CYP), PB has since been broadly used as a model compound to study xenobiotic-induced drug metabolism and clearance. Mechanistically, PB-mediated CYP induction is linked to a number of nuclear receptors, such as the constitutive androstane receptor (CAR), pregnane X receptor (PXR), and estrogen receptor α, with CAR being the predominant regulator. Unlike prototypical agonistic ligands, PB-mediated activation of CAR does not involve direct binding with the receptor. Instead, dephosphorylation of threonine 38 in the DNA-binding domain of CAR was delineated as a key signaling event underlying PB-mediated indirect activation of CAR. Further studies revealed that such phosphorylation sites appear to be highly conserved among most human nuclear receptors. Interestingly, while PB is a pan-CAR activator in both animals and humans, PB activates human but not mouse PXR. The species-specific role of PB in gene regulation is a key determinant of its implication in xenobiotic metabolism, drug-drug interactions, energy homeostasis, and cell proliferation. In this review, we summarize the recent progress in our understanding of PB-provoked transactivation of nuclear receptors with a focus on CAR and PXR. SIGNIFICANCE STATEMENT: Extensive studies using PB as a research tool have significantly advanced our understanding of the molecular basis underlying nuclear receptor-mediated drug metabolism, drug-drug interactions, energy homeostasis, and cell proliferation. In particular, CAR has been established as a cell signaling-regulated nuclear receptor in addition to ligand-dependent functionality. This mini-review highlights the mechanisms by which PB transactivates CAR and PXR.
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Affiliation(s)
- Shuaiqian Men
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (S.M., H.W.)
| | - Hongbing Wang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (S.M., H.W.)
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Ortiz NR, Guy N, Garcia YA, Sivils JC, Galigniana MD, Cox MB. Functions of the Hsp90-Binding FKBP Immunophilins. Subcell Biochem 2023; 101:41-80. [PMID: 36520303 DOI: 10.1007/978-3-031-14740-1_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The Hsp90 chaperone is known to interact with a diverse array of client proteins. However, in every case examined, Hsp90 is also accompanied by a single or several co-chaperone proteins. One class of co-chaperone contains a tetratricopeptide repeat (TPR) domain that targets the co-chaperone to the C-terminal region of Hsp90. Within this class are Hsp90-binding peptidylprolyl isomerases, most of which belong to the FK506-binding protein (FKBP) family. Despite the common association of FKBP co-chaperones with Hsp90, it is abundantly clear that the client protein influences, and is often influenced by, the particular FKBP bound to Hsp90. Examples include Xap2 in aryl hydrocarbon receptor complexes and FKBP52 in steroid receptor complexes. In this chapter, we discuss the known functional roles played by FKBP co-chaperones and, where possible, relate distinctive functions to structural differences between FKBP members.
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Affiliation(s)
- Nina R Ortiz
- Border Biomedical Research Center and Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA
| | - Naihsuan Guy
- Border Biomedical Research Center and Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA
| | - Yenni A Garcia
- Border Biomedical Research Center and Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA
| | - Jeffrey C Sivils
- Border Biomedical Research Center and Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA
| | - Mario D Galigniana
- Departamento de Química Biológica/IQUIBICEN, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Biología y Medicina Experimental/CONICET, Buenos Aires, Argentina
| | - Marc B Cox
- Border Biomedical Research Center and Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA.
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Texas at El Paso, El Paso, TX, USA.
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Khazaal AQ, Haque N, Krager CR, Krager SL, Chambers C, Wilber A, Tischkau SA. Aryl hydrocarbon receptor affects circadian-regulated lipolysis through an E-Box-dependent mechanism. Mol Cell Endocrinol 2023; 559:111809. [PMID: 36283500 PMCID: PMC10509633 DOI: 10.1016/j.mce.2022.111809] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 10/17/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022]
Abstract
An internal circadian clock regulates timing of systemic energy homeostasis. The central clock in the hypothalamic suprachiasmatic nucleus (SCN) directs local clocks in peripheral tissues such as liver, muscle, and adipose tissue to synchronize metabolism with food intake and rest/activity cycles. Aryl hydrocarbon receptor (AhR) interacts with the molecular circadian clockworks. Activation of AhR dampens rhythmic expression of core clock genes, which may lead to metabolic dysfunction. Given the importance of appropriately-timed adipose tissue function to regulation of energy homeostasis, this study focused on mechanisms by which AhR may influence clock-controlled adipose tissue activity. We hypothesized that AhR activation in adipose tissue would impair lipolysis by dampening adipose rhythms, leading to a decreased lipolysis rate during fasting, and subsequently, altered serum glucose concentrations. Levels of clock gene and lipolysis gene transcripts in mouse mesenchymal stem cells (BMSCs) differentiated into mature adipocytes were suppressed by the AhR agonist β-napthoflavone (BNF), in an AhR dependent manner. BNF altered rhythms of core clock gene and lipolysis gene transcripts in C57bl6/J mice. BNF reduced serum free fatty acids, glycerol and liver glycogen. Chromatin immunoprecipitation indicated that BNF increased binding of AhR to E-Box elements in clock gene and lipolysis gene promoters. These data establish a link between AhR activation and impaired lipolysis, specifically by altering adipose tissue rhythmicity. In response to the decreased available energy from impaired lipolysis, the body increases glycogenolysis, thereby degrading more glycogen to provide necessary energy.
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Affiliation(s)
- Ali Qasim Khazaal
- Biotechnology Department, College of Science, University of Baghdad, Baghdad, Iraq; Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Nazmul Haque
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Callie R Krager
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Stacey L Krager
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Christopher Chambers
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Andrew Wilber
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Shelley A Tischkau
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA; Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA.
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8
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Riaz F, Pan F, Wei P. Aryl hydrocarbon receptor: The master regulator of immune responses in allergic diseases. Front Immunol 2022; 13:1057555. [PMID: 36601108 PMCID: PMC9806217 DOI: 10.3389/fimmu.2022.1057555] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 12/02/2022] [Indexed: 12/23/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR) is a widely studied ligand-activated cytosolic transcriptional factor that has been associated with the initiation and progression of various diseases, including autoimmune diseases, cancers, metabolic syndromes, and allergies. Generally, AhR responds and binds to environmental toxins/ligands, dietary ligands, and allergens to regulate toxicological, biological, cellular responses. In a canonical signaling manner, activation of AhR is responsible for the increase in cytochrome P450 enzymes which help individuals to degrade and metabolize these environmental toxins and ligands. However, canonical signaling cannot be applied to all the effects mediated by AhR. Recent findings indicate that activation of AhR signaling also interacts with some non-canonical factors like Kruppel-like-factor-6 (KLF6) or estrogen-receptor-alpha (Erα) to affect the expression of downstream genes. Meanwhile, enormous research has been conducted to evaluate the effect of AhR signaling on innate and adaptive immunity. It has been shown that AhR exerts numerous effects on mast cells, B cells, macrophages, antigen-presenting cells (APCs), Th1/Th2 cell balance, Th17, and regulatory T cells, thus, playing a significant role in allergens-induced diseases. This review discussed how AhR mediates immune responses in allergic diseases. Meanwhile, we believe that understanding the role of AhR in immune responses will enhance our knowledge of AhR-mediated immune regulation in allergic diseases. Also, it will help researchers to understand the role of AhR in regulating immune responses in autoimmune diseases, cancers, metabolic syndromes, and infectious diseases.
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Affiliation(s)
- Farooq Riaz
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences (CAS), Shenzhen, China
| | - Fan Pan
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences (CAS), Shenzhen, China,*Correspondence: Ping Wei, ; Fan Pan,
| | - Ping Wei
- Department of Otolaryngology, Children’s Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Chongqing, China,*Correspondence: Ping Wei, ; Fan Pan,
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9
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An overview of aryl hydrocarbon receptor ligands in the Last two decades (2002–2022): A medicinal chemistry perspective. Eur J Med Chem 2022; 244:114845. [DOI: 10.1016/j.ejmech.2022.114845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/28/2022] [Accepted: 10/08/2022] [Indexed: 11/21/2022]
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10
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Plant Occurring Flavonoids as Modulators of the Aryl Hydrocarbon Receptor. Molecules 2021; 26:molecules26082315. [PMID: 33923487 PMCID: PMC8073824 DOI: 10.3390/molecules26082315] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 12/26/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR) is a transcription factor deeply implicated in health and diseases. Historically identified as a sensor of xenobiotics and mainly toxic substances, AhR has recently become an emerging pharmacological target in cancer, immunology, inflammatory conditions, and aging. Multiple AhR ligands are recognized, with plant occurring flavonoids being the largest group of natural ligands of AhR in the human diet. The biological implications of the modulatory effects of flavonoids on AhR could be highlighted from a toxicological and environmental concern and for the possible pharmacological applicability. Overall, the possible AhR-mediated harmful and/or beneficial effects of flavonoids need to be further investigated, since in many cases they are contradictory. Similar to other AhR modulators, flavonoids commonly exhibit tissue, organ, and species-specific activities on AhR. Such cellular-context dependency could be probably beneficial in their pharmacotherapeutic use. Flavones, flavonols, flavanones, and isoflavones are the main subclasses of flavonoids reported as AhR modulators. Some of the structural features of these groups of flavonoids that could be influencing their AhR effects are herein summarized. However, limited generalizations, as well as few outright structure-activity relationships can be suggested on the AhR agonism and/or antagonism caused by flavonoids.
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Zaragoza-Ojeda M, Apatiga-Vega E, Arenas-Huertero F. Role of aryl hydrocarbon receptor in central nervous system tumors: Biological and therapeutic implications. Oncol Lett 2021; 21:460. [PMID: 33907570 PMCID: PMC8063300 DOI: 10.3892/ol.2021.12721] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 01/25/2021] [Indexed: 12/12/2022] Open
Abstract
Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor, whose canonical pathway mainly regulates the genes involved in xenobiotic metabolism. However, it can also regulate several responses in a non-canonical manner, such as proliferation, differentiation, cell death and cell adhesion. AhR plays an important role in central nervous system tumors, as it can regulate several cellular responses via different pathways. The polymorphisms of the AHR gene have been associated with the development of gliomas. In addition, the metabolism of tumor cells promotes tumor growth, particularly in tryptophan synthesis, where some metabolites, such as kynurenine, can activate the AhR pathway, triggering cell proliferation in astrocytomas, medulloblastomas and glioblastomas. Furthermore, as part of the changes in neuroblastomas, AHR is able to downregulate the expression of proto-oncogene c-Myc, induce differentiation in tumor cells, and cause cell cycle arrest and apoptosis. Collectively, these data suggested that the modulation of the AhR pathway may downregulate tumor growth, providing a novel strategy for applications for the treatment of certain tumors through the control of the AhR pathway.
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Affiliation(s)
- Montserrat Zaragoza-Ojeda
- Laboratorio de Investigación en Patología Experimental, Hospital Infantil de México Federico Gómez, Mexico City 06720, México.,Posgrado en Ciencias Biológicas, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, México
| | - Elisa Apatiga-Vega
- Laboratorio de Investigación en Patología Experimental, Hospital Infantil de México Federico Gómez, Mexico City 06720, México
| | - Francisco Arenas-Huertero
- Laboratorio de Investigación en Patología Experimental, Hospital Infantil de México Federico Gómez, Mexico City 06720, México
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12
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Jurgelewicz A, Dornbos P, Warren M, Nault R, Arkatkar A, Lin H, Threadgill DW, Zacharewski T, LaPres JJ. Genetics-Based Approach to Identify Novel Genes Regulated by the Aryl Hydrocarbon Receptor in Mouse Liver. Toxicol Sci 2021; 181:285-294. [PMID: 33720361 PMCID: PMC8599770 DOI: 10.1093/toxsci/kfab032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor in the Per-Arnt-Sim superfamily of environmental sensors that is linked to several metabolic diseases, including nonalcoholic fatty liver disease. Much remains unknown regarding the impact of genetic variation in AHR-driven disease, as past studies have focused on a small number of inbred strains. Recently, the presence of a wide range of interindividual variability amongst humans was reported in response to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the prototypical ligand of the AHR. In this study, a panel of 14 diverse mouse strains was exposed to TCDD for 10 days to characterize the AHR-mediated response across genetic backgrounds. Responses to TCDD are heavily dependent on genetic background. Although mice carry 1 of 4 Ahr alleles known to impact the affinity to AHR-ligands, we observed significant intra-allelic variability suggesting the presence of novel genetic modifiers of AHR signaling. A regression-based approach was used to scan for genes regulated by the AHR and/or associated with TCDD-induced phenotypes. The approach identified 7 genes, 2 of which are novel, that are likely regulated by the AHR based on association with hepatic TCDD burden (p ≤ .05). Finally, we identified 1 gene, Dio1, which was associated with change in percent body fat across the diverse set of strains (p ≤ .05). Overall, the results in this study exemplify the power of genetics-based approaches in identifying novel genes that are putatively regulated by the AHR.
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Affiliation(s)
- Amanda Jurgelewicz
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan 48824, USA,Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824, USA
| | - Peter Dornbos
- Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824, USA,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
| | - Melanie Warren
- Interdisciplinary Program in Toxicology, Texas A&M University, College Station, Texas 77843, USA
| | - Rance Nault
- Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824, USA,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
| | - Anooj Arkatkar
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
| | - Hui Lin
- The Dow Chemical Company, Environmental Technology Center, Midland, Michigan 48674, USA
| | - David W Threadgill
- Interdisciplinary Program in Toxicology, Texas A&M University, College Station, Texas 77843, USA
| | - Tim Zacharewski
- Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824, USA,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
| | - John J LaPres
- Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824, USA,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA,To whom correspondence should be addressed at Department of Biochemistry and Molecular Biology, Michigan State University, 603 Wilson Road, Room 224, East Lansing, MI 48824-1319. E-mail:
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13
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Torti MF, Giovannoni F, Quintana FJ, García CC. The Aryl Hydrocarbon Receptor as a Modulator of Anti-viral Immunity. Front Immunol 2021; 12:624293. [PMID: 33746961 PMCID: PMC7973006 DOI: 10.3389/fimmu.2021.624293] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 02/03/2021] [Indexed: 12/30/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor, which interacts with a wide range of organic molecules of endogenous and exogenous origin, including environmental pollutants, tryptophan metabolites, and microbial metabolites. The activation of AHR by these agonists drives its translocation into the nucleus where it controls the expression of a large number of target genes that include the AHR repressor (AHRR), detoxifying monooxygenases (CYP1A1 and CYP1B1), and cytokines. Recent advances reveal that AHR signaling modulates aspects of the intrinsic, innate and adaptive immune response to diverse microorganisms. This review will focus on the increasing evidence supporting a role for AHR as a modulator of the host response to viral infection.
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Affiliation(s)
- Maria Florencia Torti
- Laboratory of Antiviral Strategies, Biochemistry Department, School of Sciences, University of Buenos Aires, IQUIBICEN-Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Federico Giovannoni
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Francisco Javier Quintana
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Cybele Carina García
- Laboratory of Antiviral Strategies, Biochemistry Department, School of Sciences, University of Buenos Aires, IQUIBICEN-Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
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14
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Avilla MN, Malecki KMC, Hahn ME, Wilson RH, Bradfield CA. The Ah Receptor: Adaptive Metabolism, Ligand Diversity, and the Xenokine Model. Chem Res Toxicol 2020; 33:860-879. [PMID: 32259433 PMCID: PMC7175458 DOI: 10.1021/acs.chemrestox.9b00476] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Indexed: 12/12/2022]
Abstract
The Ah receptor (AHR) has been studied for almost five decades. Yet, we still have many important questions about its role in normal physiology and development. Moreover, we still do not fully understand how this protein mediates the adverse effects of a variety of environmental pollutants, such as the polycyclic aromatic hydrocarbons (PAHs), the chlorinated dibenzo-p-dioxins ("dioxins"), and many polyhalogenated biphenyls. To provide a platform for future research, we provide the historical underpinnings of our current state of knowledge about AHR signal transduction, identify a few areas of needed research, and then develop concepts such as adaptive metabolism, ligand structural diversity, and the importance of proligands in receptor activation. We finish with a discussion of the cognate physiological role of the AHR, our perspective on why this receptor is so highly conserved, and how we might think about its cognate ligands in the future.
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Affiliation(s)
- Mele N. Avilla
- Molecular and Environmental Toxicology
Center, Department of Population Health
Sciences, University of Wisconsin School
of Medicine and Public Health, Madison, Wisconsin 53726-2379, United States
| | - Kristen M. C. Malecki
- Molecular and Environmental Toxicology
Center, Department of Population Health
Sciences, University of Wisconsin School
of Medicine and Public Health, Madison, Wisconsin 53726-2379, United States
| | - Mark E. Hahn
- Biology
Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543-1050, United States
| | - Rachel H. Wilson
- Molecular and Environmental Toxicology
Center, Department of Population Health
Sciences, University of Wisconsin School
of Medicine and Public Health, Madison, Wisconsin 53726-2379, United States
| | - Christopher A. Bradfield
- Molecular and Environmental Toxicology
Center, Department of Population Health
Sciences, University of Wisconsin School
of Medicine and Public Health, Madison, Wisconsin 53726-2379, United States
- McArdle
Laboratory for Cancer Research, University of Wisconsin School of Medicine
and Public Health, Madison, Wisconsin 53705-227, United States
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15
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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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16
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Dolciami D, Ballarotto M, Gargaro M, López-Cara LC, Fallarino F, Macchiarulo A. Targeting Aryl hydrocarbon receptor for next-generation immunotherapies: Selective modulators (SAhRMs) versus rapidly metabolized ligands (RMAhRLs). Eur J Med Chem 2019; 185:111842. [PMID: 31727470 DOI: 10.1016/j.ejmech.2019.111842] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/30/2019] [Accepted: 10/30/2019] [Indexed: 12/12/2022]
Abstract
Aryl Hydrocarbon Receptor (AhR) constitutes a major network hub of genomic and non-genomic signaling pathways, connecting host's immune cells to environmental factors. It shapes innate and adaptive immune processes to environmental stimuli with species-, cell- and tissue-type dependent specificity. Although an ever increasing number of studies has thrust AhR into the limelight as attractive target for the development of next-generation immunotherapies, concerns exist on potential safety issues associated with small molecule modulation of the receptor. Selective AhR modulators (SAhRMs) and rapidly metabolized AhR ligands (RMAhRLs) are two classes of receptor agonists that are emerging as interesting lead compounds to bypass AhR-related toxicity in favor of therapeutic effects. In this article, we discuss SAhRMs and RMAhRLs reported in literature, covering concepts underlying their definitions, specific binding modes, structure-activity relationships and AhR-mediated functions.
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Affiliation(s)
- Daniela Dolciami
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo, 1, 06123, Perugia, Italy
| | - Marco Ballarotto
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo, 1, 06123, Perugia, Italy
| | - Marco Gargaro
- Department of Experimental Medicine, University of Perugia, Piazz.le Gambuli, 1, 06132, Perugia, Italy
| | - Luisa Carlota López-Cara
- Department of Pharmaceutical & Organic Chemistry, Faculty of Pharmacy, University of Granada, 18010, Granada, Spain
| | - Francesca Fallarino
- Department of Experimental Medicine, University of Perugia, Piazz.le Gambuli, 1, 06132, Perugia, Italy
| | - Antonio Macchiarulo
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo, 1, 06123, Perugia, Italy.
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17
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Arenas-Huertero F, Zaragoza-Ojeda M, Sánchez-Alarcón J, Milić M, Šegvić Klarić M, Montiel-González JM, Valencia-Quintana R. Involvement of Ahr Pathway in Toxicity of Aflatoxins and Other Mycotoxins. Front Microbiol 2019; 10:2347. [PMID: 31681212 PMCID: PMC6798329 DOI: 10.3389/fmicb.2019.02347] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 09/26/2019] [Indexed: 12/18/2022] Open
Abstract
The purpose of this review is to present information about the role of activation of aflatoxins and other mycotoxins, of the aryl hydrocarbon receptor (AhR) pathway. Aflatoxins and other mycotoxins are a diverse group of secondary metabolites that can be contaminants in a broad range of agricultural products and feeds. Some species of Aspergillus, Alternaria, Penicilium, and Fusarium are major producers of mycotoxins, some of which are toxic and carcinogenic. Several aflatoxins are planar molecules that can activate the AhR. AhR participates in the detoxification of several xenobiotic substances and activates phase I and phase II detoxification pathways. But it is important to recognize that AhR activation also affects differentiation, cell adhesion, proliferation, and immune response among others. Any examination of the effects of aflatoxins and other toxins that act as activators to AhR must consider the potential of the disruption of several cellular functions in order to extend the perception thus far about the toxic and carcinogenic effects of these toxins. There have been no Reviews of existing data between the relation of AhR and aflatoxins and this one attempts to give information precisely about this dichotomy.
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Affiliation(s)
- Francisco Arenas-Huertero
- Experimental Pathology Research Laboratory, Children’s Hospital of Mexico Federico Gómez, Mexico, Mexico
| | - Montserrat Zaragoza-Ojeda
- Experimental Pathology Research Laboratory, Children’s Hospital of Mexico Federico Gómez, Mexico, Mexico
| | - Juana Sánchez-Alarcón
- Rafael Villalobos-Pietrini Laboratory of Genomic Toxicology and Environmental Chemistry, Faculty of Agrobiology, Autonomous University of Tlaxcala, Tlaxcala, Mexico
| | - Mirta Milić
- Mutagenesis Unit, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Maja Šegvić Klarić
- Department of Microbiology, Faculty of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia
| | - José M. Montiel-González
- Rafael Villalobos-Pietrini Laboratory of Genomic Toxicology and Environmental Chemistry, Faculty of Agrobiology, Autonomous University of Tlaxcala, Tlaxcala, Mexico
| | - Rafael Valencia-Quintana
- Rafael Villalobos-Pietrini Laboratory of Genomic Toxicology and Environmental Chemistry, Faculty of Agrobiology, Autonomous University of Tlaxcala, Tlaxcala, Mexico
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18
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Pecorelli A, Woodby B, Prieux R, Valacchi G. Involvement of 4-hydroxy-2-nonenal in pollution-induced skin damage. Biofactors 2019; 45:536-547. [PMID: 31087730 DOI: 10.1002/biof.1513] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 03/19/2019] [Accepted: 04/02/2019] [Indexed: 12/17/2022]
Abstract
The effects of environmental insults on human health are a major global concern. Some of the most noxious pollutants that humans are exposed to include ozone (O3 ), particulate matter (PM), and cigarette smoke (CS). Since the skin is the first line of defense against environmental insults, it is considered one of the main target organs for the harmful insults of air pollution. Thus, there is solid evidence that skin pathologies such as premature aging, atopic dermatitis (AD), and psoriasis are associated with pollutant exposure; all of these skin conditions are also associated with an altered redox status. Therefore, although the mechanisms of action and concentrations of O3 , PM, and CS that we are exposed to differ, exposure to all of these pollutants is associated with the development of similar skin conditions due to the fact that all of these pollutants alter redox homeostasis, increasing reactive oxygen species production and oxidative stress. A main product of oxidative stress, induced by exposure to the aforementioned pollutants, is 4-hydroxy-2-nonenal (HNE), which derives from the oxidation of ω-6 polyunsaturated fatty acids. HNE is a highly reactive compound that can form adducts with cellular proteins and even DNA; it is also an efficient cell signaling molecule able to regulate mitogen-activated protein kinase pathways and the activity of redox-sensitive transcription factors such as Nrf2, AP1, and NFκB. Therefore, increased levels of HNE in the skin, in response to pollutants, likely accelerates skin aging and exacerbates existing skin inflammatory conditions; thus, targeting HNE formation could be an innovative cosmeceutical approach for topical applications.
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Affiliation(s)
- Alessandra Pecorelli
- Plants for Human Health Institute, Department of Animal Sciences, North Carolina State University, Kannapolis, North Carolina
| | - Brittany Woodby
- Plants for Human Health Institute, Department of Animal Sciences, North Carolina State University, Kannapolis, North Carolina
| | - Roxane Prieux
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Giuseppe Valacchi
- Plants for Human Health Institute, Department of Animal Sciences, North Carolina State University, Kannapolis, North Carolina
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
- Department of Food and Nutrition, Kyung Hee University, Seoul 02447, Korea
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19
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Dornbos P, Warren M, Crawford RB, Kaminski NE, Threadgill DW, LaPres JJ. Characterizing Serpinb2 as a Modulator of TCDD-Induced Suppression of the B Cell. Chem Res Toxicol 2018; 31:1248-1259. [PMID: 30339366 DOI: 10.1021/acs.chemrestox.8b00225] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
2,3,7,8-Tetrachlordibenzo- p-dioxin (TCDD) is an environmental pollutant that can cause various toxic effects, including chloracne, metabolic syndrome, and immune suppression. Most of the toxicity associated with TCDD is mediated through activation of the aryl hydrocarbon receptor (AHR). Recent research has suggested the presence of a wide-range of interindividual variability in TCDD-mediated suppression of the Immunoglobulin-M (IgM) response across the human population. In an attempt to identify putative modifiers of AHR-mediated immunosuppression beyond the AHR, B cells were isolated from a panel of genetically diverse mouse strain to scan for modulators that drive interstrain differences in TCDD-mediated suppression of the IgM response. Results implicated a region of mouse Chromosome 1 near a gene encoding serine peptidase inhibitor, clade B, member 2 ( Serpinb2) whose human ortholog is plasminogen activator inhibitor 2 (PAI2). Further downstream analyses indicated that Serpinb2 is dysregulated by TCDD and, furthermore, that B cells from Serpinb2 -/- mice are significantly more sensitive to TCDD-mediated suppression as compared to littermate controls. This study suggests a protective role of Serpinb2 within TCDD-mediated immunosuppression and, furthermore, a novel function of Serpinb2-related activity in the IgM response.
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Affiliation(s)
- Peter Dornbos
- Department of Biochemistry and Molecular Biology , Michigan State University , East Lansing , Michigan 48824 , United States.,Institute for Integrative Toxicology , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Melanie Warren
- Interdisciplinary Program in Toxicology , Texas A&M University , College Station , Texas 77843 , United States
| | - Robert B Crawford
- Department of Pharmacology and Toxicology , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Norbert E Kaminski
- Institute for Integrative Toxicology , Michigan State University , East Lansing , Michigan 48824 , United States.,Department of Pharmacology and Toxicology , Michigan State University , East Lansing , Michigan 48824 , United States
| | - David W Threadgill
- Interdisciplinary Program in Toxicology , Texas A&M University , College Station , Texas 77843 , United States
| | - John J LaPres
- Department of Biochemistry and Molecular Biology , Michigan State University , East Lansing , Michigan 48824 , United States.,Institute for Integrative Toxicology , Michigan State University , East Lansing , Michigan 48824 , United States
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20
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Hernández-Ramírez LC, Morgan RM, Barry S, D’Acquisto F, Prodromou C, Korbonits M. Multi-chaperone function modulation and association with cytoskeletal proteins are key features of the function of AIP in the pituitary gland. Oncotarget 2018; 9:9177-9198. [PMID: 29507682 PMCID: PMC5823669 DOI: 10.18632/oncotarget.24183] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 01/01/2018] [Indexed: 11/25/2022] Open
Abstract
Despite the well-recognized role of loss-of-function mutations of the aryl hydrocarbon receptor interacting protein gene (AIP) predisposing to pituitary adenomas, the pituitary-specific function of this tumor suppressor remains an enigma. To determine the repertoire of interacting partners for the AIP protein in somatotroph cells, wild-type and variant AIP proteins were used for pull-down/quantitative mass spectrometry experiments against lysates of rat somatotropinoma-derived cells; relevant findings were validated by co-immunoprecipitation and co-localization. Global gene expression was studied in AIP mutation positive and negative pituitary adenomas via RNA microarrays. Direct interaction with AIP was confirmed for three known and six novel partner proteins. Novel interactions with HSPA5 and HSPA9, together with known interactions with HSP90AA1, HSP90AB1 and HSPA8, indicate that the function/stability of multiple chaperone client proteins could be perturbed by a deficient AIP co-chaperone function. Interactions with TUBB, TUBB2A, NME1 and SOD1 were also identified. The AIP variants p.R304* and p.R304Q showed impaired interactions with HSPA8, HSP90AB1, NME1 and SOD1; p.R304* also displayed reduced binding to TUBB and TUBB2A, and AIP-mutated tumors showed reduced TUBB2A expression. Our findings suggest that cytoskeletal organization, cell motility/adhesion, as well as oxidative stress responses, are functions that are likely to be involved in the tumor suppressor activity of AIP.
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Affiliation(s)
- Laura C. Hernández-Ramírez
- Centre for Endocrinology, Barts and The London School of Medicine, Queen Mary University of London, London, EC1M 6BQ, UK
- Present address: Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892-1862, USA
| | - Rhodri M.L. Morgan
- Genome Damage and Stability Centre, University of Sussex, Brighton, Falmer, BN1 9RQ, UK
- Present address: Protein Crystallography Facility, Centre for Structural Biology, Flowers Building, Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Sayka Barry
- Centre for Endocrinology, Barts and The London School of Medicine, Queen Mary University of London, London, EC1M 6BQ, UK
| | - Fulvio D’Acquisto
- Centre for Microvascular Research, Barts and The London School of Medicine, Queen Mary University of London, London, EC1M 6BQ, UK
| | | | - Márta Korbonits
- Centre for Endocrinology, Barts and The London School of Medicine, Queen Mary University of London, London, EC1M 6BQ, UK
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21
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Ibáñez-Costa A, Korbonits M. AIP and the somatostatin system in pituitary tumours. J Endocrinol 2017; 235:R101-R116. [PMID: 28835453 DOI: 10.1530/joe-17-0254] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 08/22/2017] [Indexed: 12/22/2022]
Abstract
Classic somatostatin analogues aimed at somatostatin receptor type 2, such as octreotide and lanreotide, represent the mainstay of medical treatment for acromegaly. These agents have the potential to decrease hormone secretion and reduce tumour size. Patients with a germline mutation in the aryl hydrocarbon receptor-interacting protein gene, AIP, develop young-onset acromegaly, poorly responsive to pharmacological therapy. In this review, we summarise the most recent studies on AIP-related pituitary adenomas, paying special attention to the causes of somatostatin resistance; the somatostatin receptor profile including type 2, type 5 and truncated variants; the role of G proteins in this pathology; the use of first and second generation somatostatin analogues; and the role of ZAC1, a zinc-finger protein with expression linked to AIP in somatotrophinoma models and acting as a key mediator of octreotide response.
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Affiliation(s)
- Alejandro Ibáñez-Costa
- Centre for EndocrinologyWilliam Harvey Research Institute, Barts and The London School of Medicine, Queen Mary University of London, London, UK
| | - Márta Korbonits
- Centre for EndocrinologyWilliam Harvey Research Institute, Barts and The London School of Medicine, Queen Mary University of London, London, UK
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22
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Sakurai S, Shimizu T, Ohto U. The crystal structure of the AhRR-ARNT heterodimer reveals the structural basis of the repression of AhR-mediated transcription. J Biol Chem 2017; 292:17609-17616. [PMID: 28904176 DOI: 10.1074/jbc.m117.812974] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 09/12/2017] [Indexed: 12/19/2022] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin and related compounds are extraordinarily potent environmental toxic pollutants. Most of the 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicities are mediated by aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor belonging to the basic helix-loop-helix (bHLH) Per-ARNT-Sim (PAS) family. Upon ligand binding, AhR forms a heterodimer with AhR nuclear translocator (ARNT) and induces the expression of genes involved in various biological responses. One of the genes induced by AhR encodes AhR repressor (AhRR), which also forms a heterodimer with ARNT and represses the activation of AhR-dependent transcription. The control of AhR activation is critical for managing AhR-mediated diseases, but the mechanisms by which AhRR represses AhR activation remain poorly understood, because of the lack of structural information. Here, we determined the structure of the AhRR-ARNT heterodimer by X-ray crystallography, which revealed an asymmetric intertwined domain organization presenting structural features that are both conserved and distinct among bHLH-PAS family members. The structures of AhRR-ARNT and AhR-ARNT were similar in the bHLH-PAS-A region, whereas the PAS-B of ARNT in the AhRR-ARNT complex exhibited a different domain arrangement in this family reported so far. The structure clearly disclosed that AhRR competitively represses AhR binding to ARNT and target DNA and further suggested the existence of an AhRR-ARNT-specific repression mechanism. This study provides a structural basis for understanding the mechanism by which AhRR represses AhR-mediated gene transcription.
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Affiliation(s)
- Shunya Sakurai
- From the Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan and
| | - Toshiyuki Shimizu
- From the Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan and .,the Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Saitama 332-0012, Japan
| | - Umeharu Ohto
- From the Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan and
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23
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Structural hierarchy controlling dimerization and target DNA recognition in the AHR transcriptional complex. Proc Natl Acad Sci U S A 2017; 114:5431-5436. [PMID: 28396409 DOI: 10.1073/pnas.1617035114] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) belongs to the PAS (PER-ARNT-SIM) family transcription factors and mediates broad responses to numerous environmental pollutants and cellular metabolites, modulating diverse biological processes from adaptive metabolism, acute toxicity, to normal physiology of vascular and immune systems. The AHR forms a transcriptionally active heterodimer with ARNT (AHR nuclear translocator), which recognizes the dioxin response element (DRE) in the promoter of downstream genes. We determined the crystal structure of the mammalian AHR-ARNT heterodimer in complex with the DRE, in which ARNT curls around AHR into a highly intertwined asymmetric architecture, with extensive heterodimerization interfaces and AHR interdomain interactions. Specific recognition of the DRE is determined locally by the DNA-binding residues, which discriminates it from the closely related hypoxia response element (HRE), and is globally affected by the dimerization interfaces and interdomain interactions. Changes at the interdomain interactions caused either AHR constitutive nuclear localization or failure to translocate to nucleus, underlying an allosteric structural pathway for mediating ligand-induced exposure of nuclear localization signal. These observations, together with the global higher flexibility of the AHR PAS-A and its loosely packed structural elements, suggest a dynamic structural hierarchy for complex scenarios of AHR activation induced by its diverse ligands.
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24
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Hernández-Ramírez LC, Trivellin G, Stratakis CA. Role of Phosphodiesterases on the Function of Aryl Hydrocarbon Receptor-Interacting Protein (AIP) in the Pituitary Gland and on the Evaluation of AIP Gene Variants. Horm Metab Res 2017; 49:286-295. [PMID: 28427099 DOI: 10.1055/s-0043-104700] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Familial isolated pituitary adenoma (FIPA) is caused in about 20% of cases by loss-of-function germline mutations in the AIP gene. Patients harboring AIP mutations usually present with somatotropinomas resulting either in gigantism or young-onset acromegaly. AIP encodes for a co-chaperone protein endowed with tumor suppressor properties in somatotroph cells. Among other mechanisms proposed to explain this function, a regulatory effect over the 3',5'-cyclic adenosine monophosphate (cAMP) signaling pathway seems to play a prominent role. In this setting, the well-known interaction between AIP and 2 different isoforms of phosphodiesterases (PDEs), PDE2A3 and PDE4A5, is of particular interest. While the interaction with over-expressed AIP does not seem to affect PDE2A3 function, the reported effect on PDE4A5 is, in contrast, reduced enzymatic activity. In this review, we explore the possible implications of these molecular interactions for the function of somatotroph cells. In particular, we discuss how both PDEs and AIP could act as negative regulators of the cAMP pathway in the pituitary, probably both by shared and independent mechanisms. Moreover, we describe how the evaluation of the AIP-PDE4A5 interaction has proven to be a useful tool for testing AIP mutations, complementing other in silico, in vitro, and in vivo analyses. Improved assessment of the pathogenicity of AIP mutations is indeed paramount to provide adequate guidance for genetic counseling and clinical screening in AIP mutation carriers, which can lead to prospective diagnosis of pituitary adenomas.
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Affiliation(s)
- Laura C Hernández-Ramírez
- Section on Endocrinology and Genetics (SEGEN), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Giampaolo Trivellin
- Section on Endocrinology and Genetics (SEGEN), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics (SEGEN), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
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25
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Wright EJ, De Castro KP, Joshi AD, Elferink CJ. Canonical and non-canonical aryl hydrocarbon receptor signaling pathways. CURRENT OPINION IN TOXICOLOGY 2017; 2:87-92. [PMID: 32296737 DOI: 10.1016/j.cotox.2017.01.001] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Decades of research on the Aryl hydrocarbon Receptor (AhR) has unveiled its involvement in the toxicity of halogenated and polycyclic aromatic hydrocarbons, and a myriad of normal physiological processes. The molecular dissection of AhR biology has centered on a canonical signaling pathway in an effort to mechanistically reconcile the diverse pathophysiological effects of exposure to environmental pollutants. As a consequence, we now know that canonical signaling can explain many but not all of the AhR-mediated effects. Here we describe recent findings that point to non-canonical signaling pathways, and focus on a novel AhR interaction with the Krüppel-like Factor 6 protein responsible for previously un-recognized epigenetic changes in the chromatin affecting gene expression.
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Affiliation(s)
- Eric J Wright
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0654, USA
| | - Karen Pereira De Castro
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0654, USA
| | - Aditya D Joshi
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0654, USA
| | - Cornelis J Elferink
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0654, USA
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SHP-1 is directly activated by the aryl hydrocarbon receptor and regulates BCL-6 in the presence of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Toxicol Appl Pharmacol 2016; 310:41-50. [PMID: 27546522 DOI: 10.1016/j.taap.2016.08.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 08/12/2016] [Accepted: 08/16/2016] [Indexed: 01/17/2023]
Abstract
The environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which is a strong AHR agonist, causes significant suppression of human B cell activation and differentiation. The current studies describe the identification of Src homology phosphatase 1 (SHP-1) encoded by the gene PTPN6 as a putative regulator of TCDD-mediated suppression of B cell activation. Shp-1 was initially identified through a genome-wide analysis of AHR binding in mouse B cells in the presence of TCDD. The binding of AHR to the PTPN6 promoter was further confirmed using electrophoretic mobility shift assays in which, specific binding of AHR was detected at four putative DRE sites within PTPN6 promoter. Time-course measurements performed in human B cells highlighted a significant increase in SHP-1 mRNA and protein levels in the presence of TCDD. The changes in the protein levels of SHP-1 were also observed in a TCDD concentration-dependent manner. The increase in SHP-1 levels was also seen to occur due to a change in early signaling events in the presence of TCDD. We have shown that BCL-6 regulates B cell activation by repressing activation marker CD80 in the presence of TCDD. TCDD-treatment led to a significant increase in the double positive (SHP-1hi BCL-6hi) population. Interestingly, treatment of naïve human B cells with SHP-1 inhibitor decreased BCL-6 protein levels suggesting possible regulation of BCL-6 by SHP-1 for the first time. Collectively, these results suggest that SHP-1 is regulated by AHR in the presence of TCDD and may, in part through BCL-6, regulate TCDD-mediated suppression of human B cell activation.
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Dornbos P, Crawford RB, Kaminski NE, Hession SL, LaPres JJ. The Influence of Human Interindividual Variability on the Low-Dose Region of Dose-Response Curve Induced by 2,3,7,8-Tetrachlorodibenzo-p-Dioxin in Primary B Cells. Toxicol Sci 2016; 153:352-60. [PMID: 27473338 PMCID: PMC5036619 DOI: 10.1093/toxsci/kfw128] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The influence of interindividual variability is not typically assessed in traditional toxicological studies. Given that chemical exposures occur in heterogeneous populations, this knowledge gap has the potential to cause undue harm within the realms of public health and industrial and municipal finances. A recent report from the National Research Council (NRC) suggests that when accounting for interindividual variation in responses, traditionally assumed nonlinear dose-response relationships (DRRs) for noncancer-causing endpoints would better be explained with a linear relationship within the low-dose region. To address this knowledge gap and directly test the NRC's assumption, this study focused on assessing the DRR between 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD) exposure and immune suppression in a cohort of unique human donors. Human B cells were isolated from 51 individual donors and treated with logarithmically increasing concentrations of TCDD (0-30 nM TCDD). Two endpoints sensitive to TCDD were assessed: (1) number of IgM-secreting B cells and (2) quantity of IgM secreted. The results show that TCDD significantly suppressed both the number of IgM-secreting B cells and the quantity of IgM secreted (P < .05). Statistical model comparisons indicate that the low-dose region of the two DRRs is best explained with a nonlinear relationship. Rather than assuming low-dose linearity for all noncancer-causing DRRs, our study suggests the need to consider the specific mode of action of toxicants and pharmaceuticals during risk-management decision making.
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Affiliation(s)
- Peter Dornbos
- *Department of Biochemistry and Molecular Biology Institute for Integrative Toxicology
| | | | - Norbert E Kaminski
- Department of Pharmacology and Toxicology Institute for Integrative Toxicology
| | | | - John J LaPres
- *Department of Biochemistry and Molecular Biology Institute for Integrative Toxicology Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, Michigan
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Lecoq AL, Zizzari P, Hage M, Decourtye L, Adam C, Viengchareun S, Veldhuis JD, Geoffroy V, Lombès M, Tolle V, Guillou A, Karhu A, Kappeler L, Chanson P, Kamenický P. Mild pituitary phenotype in 3- and 12-month-old Aip-deficient male mice. J Endocrinol 2016; 231:59-69. [PMID: 27621108 DOI: 10.1530/joe-16-0190] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 08/08/2016] [Indexed: 12/30/2022]
Abstract
Germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene predispose humans to pituitary adenomas, particularly of the somatotroph lineage. Mice with global heterozygous inactivation of Aip (Aip(+/-)) also develop pituitary adenomas but differ from AIP-mutated patients by the high penetrance of pituitary disease. The endocrine phenotype of these mice is unknown. The aim of this study was to determine the endocrine phenotype of Aip(+/-) mice by assessing the somatic growth, ultradian pattern of GH secretion and IGF1 concentrations of longitudinally followed male mice at 3 and 12 months of age. As the early stages of pituitary tumorigenesis are controversial, we also studied the pituitary histology and somatotroph cell proliferation in these mice. Aip(+/-) mice did not develop gigantism but exhibited a leaner phenotype than wild-type mice. Analysis of GH pulsatility by deconvolution in 12-month-old Aip(+/-) mice showed a mild increase in total GH secretion, a conserved GH pulsatility pattern, but a normal IGF1 concentration. No pituitary adenomas were detected up to 12 months of age. An increased ex vivo response to GHRH of pituitary explants from 3-month-old Aip(+/-) mice, together with areas of enlarged acini identified on reticulin staining in the pituitary of some Aip(+/-) mice, was suggestive of somatotroph hyperplasia. Global heterozygous Aip deficiency in mice is accompanied by subtle increase in GH secretion, which does not result in gigantism. The absence of pituitary adenomas in 12-month-old Aip(+/-) mice in our experimental conditions demonstrates the important phenotypic variability of this congenic mouse model.
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Affiliation(s)
- Anne-Lise Lecoq
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, France
| | - Philippe Zizzari
- Inserm U894Centre de Psychiatrie et Neurosciences, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Mirella Hage
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, France
| | - Lyvianne Decourtye
- Sorbonne UniversitésUniv Paris 06 UMRS 938, Inserm U938, CDR Saint-Antoine, Paris, France
| | - Clovis Adam
- Assistance Publique-Hôpitaux de ParisService d'Anatomie et Cytologie Pathologiques, Hôpital Bicêtre, Le Kremlin Bicêtre, France
| | - Say Viengchareun
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, France
| | - Johannes D Veldhuis
- Department of MedicineEndocrine Research Unit, Mayo School of Graduate Medical Education, Clinical Translational Science Center, Mayo Clinic, Rochester, Minnesota, USA
| | - Valérie Geoffroy
- Inserm U1132Hôpital Lariboisière, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Marc Lombès
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, France
| | - Virginie Tolle
- Inserm U894Centre de Psychiatrie et Neurosciences, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Anne Guillou
- Unité Mixte de Recherche-5203Centre National de la Recherche Scientifique, Institut de Génomique Fonctionnelle, Montpellier, France
| | - Auli Karhu
- Department of Medical GeneticsGenome-Scale Biology Research Program Biomedicum, University of Helsinki, Helsinki, Finland
| | - Laurent Kappeler
- Sorbonne UniversitésUniv Paris 06 UMRS 938, Inserm U938, CDR Saint-Antoine, Paris, France
| | - Philippe Chanson
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, France Assistance Publique-Hôpitaux de ParisService d'Endocrinologie et des Maladies de la Reproduction, Hôpital Bicêtre, Le Kremlin Bicêtre, France
| | - Peter Kamenický
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, France Assistance Publique-Hôpitaux de ParisService d'Endocrinologie et des Maladies de la Reproduction, Hôpital Bicêtre, Le Kremlin Bicêtre, France
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Phadnis-Moghe AS, Chen W, Li J, Crawford RB, Bach A, D'Ingillo S, Kovalova N, Suarez-Martinez JE, Kaplan BLF, Harrill JA, Budinsky R, Rowlands JC, Thomas RS, Kaminski NE. Immunological characterization of the aryl hydrocarbon receptor (AHR) knockout rat in the presence and absence of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Toxicology 2016; 368-369:172-182. [PMID: 27590929 DOI: 10.1016/j.tox.2016.08.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 08/01/2016] [Accepted: 08/30/2016] [Indexed: 12/15/2022]
Abstract
The aryl hydrocarbon receptor (AHR) has been extensively characterized for the essential role it plays in mediating the toxic responses elicited by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Despite similarities across animal species, species-specific differences exist in the profile of toxicity and sensitivity to TCDD owing, in part, to differences in the AHR. Newer reports have implicated the importance of AHR in the development and regulation of the immune system. Our present studies seek to further explore the essential role of AHR in lymphoid tissue composition, B cell function and the immunological responses after TCDD administration using the recently established AHR KO rats. Comprehensive immune cell phenotyping showed a decrease in the CD8+ T cell, CD11c+ populations and an increase in NKT cells in 3-week-old AHR KO rats compared to the WT controls. The lipopolysaccharide-induced IgM response and proliferation was markedly suppressed in the WT but not in the AHR KO B cells in the presence of TCDD. However, the percentage of LPS-activated IgM+ B cells was significantly higher in the AHR KO B cells as compared to that of WT suggesting the role of AHR in regulating the IgM response. The use of an AHR antagonist further alluded to the endogenous role of AHR in regulating B cell responses in the rat. Overall, the studies report for the first time, comprehensive immune cell phenotyping of the AHR KO rat and the endogenous role of AHR in the regulation of B cell function in the rat.
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Affiliation(s)
- Ashwini S Phadnis-Moghe
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Weimin Chen
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Jinpeng Li
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Genetics Program, Michigan State University, East Lansing, MI, 48824, United States
| | - Robert B Crawford
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Anthony Bach
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Shawna D'Ingillo
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Natalia Kovalova
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Jose E Suarez-Martinez
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Barbara L F Kaplan
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Joshua A Harrill
- The Hamner Institutes for Health Sciences, 6 Davis Drive, P.O. Box 12137, Research Triangle Park, NC, 27709, United States
| | | | | | - Russell S Thomas
- The Hamner Institutes for Health Sciences, 6 Davis Drive, P.O. Box 12137, Research Triangle Park, NC, 27709, United States
| | - Norbert E Kaminski
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, United States.
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30
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Role of aryl hydrocarbon receptor polymorphisms on TCDD-mediated CYP1B1 induction and IgM suppression by human B cells. Toxicol Appl Pharmacol 2016; 309:15-23. [PMID: 27535091 DOI: 10.1016/j.taap.2016.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 12/14/2022]
Abstract
Previous studies have demonstrated that most of the intraspecies variation in sensitivity to the toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), including suppression of antibody responses, in murine models is due to single nucleotide polymorphisms (SNPs) within the aryl hydrocarbon receptor (AhR) gene. The underlying reason for variation in sensitivity to TCDD-induced suppression of IgM responses among humans is not well understood, but is thought, in part, to be a result of different polymorphic forms of the AhR expressed by different individuals. In this study, the functional properties of six (P517S, R554K, V570I, V570I+P517S, R554K+V570I and P517S+R554K+V570I) human AhR variants were examined in the human B cell line, SKW 6.4. TCDD-induced Cyp1B1 and Cyp1A2 mRNA expression levels and Cyp1B1-regulated reporter gene activity, used for comparative purposes, were markedly lower in SKW cells containing the R554K SNP than in SKW-AHR(+) (control AhR) cells. Furthermore, all AhR variants were able to mediate TCDD-induced suppression of the IgM response; however, a combined P517S+R554K+V570I variant partially reduced sensitivity to TCDD-mediated suppression of IgM secretion. Collectively, our findings show that the R554K human AhR SNP alone altered sensitivity of human B cells to TCDD-mediated induction of Cyp1B1 and Cyp1A2. By contrast, attenuation of TCDD-induced IgM suppression required a combination of all three SNPs P517S, R554K, and V570I.
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31
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Lecoq AL, Viengchareun S, Hage M, Bouligand J, Young J, Boutron A, Zizzari P, Lombès M, Chanson P, Kamenický P. AIP mutations impair AhR signaling in pituitary adenoma patients fibroblasts and in GH3 cells. Endocr Relat Cancer 2016; 23:433-43. [PMID: 27080473 DOI: 10.1530/erc-16-0041] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 04/14/2016] [Indexed: 12/30/2022]
Abstract
Germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene predispose humans to pituitary adenomas through unknown molecular mechanisms. The best-known interacting partner of AIP is the aryl hydrocarbon receptor (AhR), a transcription factor that mediates the effects of xenobiotics implicated in carcinogenesis. As 75% of AIP mutations disrupt the physical and/or functional interaction with AhR, we postulated that the tumorigenic potential of AIP mutations might result from altered AhR signaling. We evaluated the impact of AIP mutations on the AhR signaling pathway, first in fibroblasts from AIP-mutated patients with pituitary adenomas, by comparison with fibroblasts from healthy subjects, then in transfected pituitary GH3 cells. The AIP protein level in mutated fibroblasts was about half of that in cells from healthy subjects, but AhR expression was unaffected. Gene expression analyses showed significant modifications in the expression of the AhR target genes CYP1B1 and AHRR in AIP-mutated fibroblasts, both before and after stimulation with the endogenous AhR ligand kynurenine. Kynurenine increased Cyp1b1 expression to a greater extent in GH3 cells overexpressing wild type compared with cells expressing mutant AIP Knockdown of endogenous Aip in these cells attenuated Cyp1b1 induction by the AhR ligand. Both mutant AIP expression and knockdown of endogenous Aip affected the kynurenine-dependent GH secretion of GH3 cells. This study of human fibroblasts bearing endogenous heterozygous AIP mutations and transfected pituitary GH3 cells shows that AIP mutations affect the AIP protein level and alter AhR transcriptional activity in a gene- and tissue-dependent manner.
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Affiliation(s)
- Anne-Lise Lecoq
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Université Paris Saclay, Le Kremlin-Bicêtre, France
| | - Say Viengchareun
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Université Paris Saclay, Le Kremlin-Bicêtre, France
| | - Mirella Hage
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Université Paris Saclay, Le Kremlin-Bicêtre, France
| | - Jérôme Bouligand
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Université Paris Saclay, Le Kremlin-Bicêtre, France Assistance Publique-Hôpitaux de ParisService de Génétique Moléculaire, Pharmacogénétique et Hormonologie, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Jacques Young
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Université Paris Saclay, Le Kremlin-Bicêtre, France Assistance Publique-Hôpitaux de ParisService d'Endocrinologie et des Maladies de la Reproduction, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Audrey Boutron
- Assistance Publique-Hôpitaux de ParisService de Biochimie, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Philippe Zizzari
- Inserm U894Centre de Psychiatrie et Neurosciences, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Marc Lombès
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Université Paris Saclay, Le Kremlin-Bicêtre, France Assistance Publique-Hôpitaux de ParisService d'Endocrinologie et des Maladies de la Reproduction, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Philippe Chanson
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Université Paris Saclay, Le Kremlin-Bicêtre, France Assistance Publique-Hôpitaux de ParisService d'Endocrinologie et des Maladies de la Reproduction, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Peter Kamenický
- Institut National de la Santé et de la Recherche Médicale (Inserm) U1185Le Kremlin-Bicêtre, France Université Paris-SudFaculté de Médecine Paris-Sud, Université Paris Saclay, Le Kremlin-Bicêtre, France Assistance Publique-Hôpitaux de ParisService d'Endocrinologie et des Maladies de la Reproduction, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
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Hwang HJ, Dornbos P, Steidemann M, Dunivin TK, Rizzo M, LaPres JJ. Mitochondrial-targeted aryl hydrocarbon receptor and the impact of 2,3,7,8-tetrachlorodibenzo-p-dioxin on cellular respiration and the mitochondrial proteome. Toxicol Appl Pharmacol 2016; 304:121-32. [PMID: 27105554 DOI: 10.1016/j.taap.2016.04.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 04/02/2016] [Accepted: 04/08/2016] [Indexed: 11/18/2022]
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor within the Per-Arnt-Sim (PAS) domain superfamily. Exposure to the most potent AHR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is associated with various pathological effects including metabolic syndrome. While research over the last several years has demonstrated a role for oxidative stress and metabolic dysfunction in AHR-dependent TCDD-induced toxicity, the role of the mitochondria in this process has not been fully explored. Our previous research suggested that a portion of the cellular pool of AHR could be found in the mitochondria (mitoAHR). Using a protease protection assay with digitonin extraction, we have now shown that this mitoAHR is localized to the inter-membrane space (IMS) of the organelle. TCDD exposure induced a degradation of mitoAHR similar to that of cytosolic AHR. Furthermore, siRNA-mediated knockdown revealed that translocase of outer-mitochondrial membrane 20 (TOMM20) was involved in the import of AHR into the mitochondria. In addition, TCDD altered cellular respiration in an AHR-dependent manner to maintain respiratory efficiency as measured by oxygen consumption rate (OCR). Stable isotope labeling by amino acids in cell culture (SILAC) identified a battery of proteins within the mitochondrial proteome influenced by TCDD in an AHR-dependent manner. Among these, 17 proteins with fold changes≥2 are associated with various metabolic pathways, suggesting a role of mitochondrial retrograde signaling in TCDD-mediated pathologies. Collectively, these studies suggest that mitoAHR is localized to the IMS and AHR-dependent TCDD-induced toxicity, including metabolic dysfunction, wasting syndrome, and hepatic steatosis, involves mitochondrial dysfunction.
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Affiliation(s)
- Hye Jin Hwang
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States; Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI 48824, United States
| | - Peter Dornbos
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States; Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824-1319, United States
| | - Michelle Steidemann
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824-1319, United States; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, United States
| | - Taylor K Dunivin
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, United States
| | - Mike Rizzo
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824-1319, United States; Cell and Molecular Biology Graduate Program, Michigan State University, East Lansing, MI 48824, United States
| | - John J LaPres
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States; Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI 48824, United States.
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Abstract
The final therapeutic effect of a drug candidate, which is directed to a specific molecular target strongly depends on its absorption, distribution, metabolism and excretion (ADME). The disruption of at least one element of ADME may result in serious drug resistance. In this work we described the role of one element of this resistance: phase II metabolism with UDP-glucuronosyltransferases (UGTs). UGT function is the transformation of their substrates into more polar metabolites, which are better substrates for the ABC transporters, MDR1, MRP and BCRP, than the native drug. UGT-mediated drug resistance can be associated with (i) inherent overexpression of the enzyme, named intrinsic drug resistance or (ii) induced expression of the enzyme, named acquired drug resistance observed when enzyme expression is induced by the drug or other factors, as food-derived compounds. Very often this induction occurs via ligand binding receptors including AhR (aryl hydrocarbon receptor) PXR (pregnane X receptor), or other transcription factors. The effect of UGT dependent resistance is strengthened by coordinate action and also a coordinate regulation of the expression of UGTs and ABC transporters. This coupling of UGT and multidrug resistance proteins has been intensively studied, particularly in the case of antitumor treatment, when this resistance is "improved" by differences in UGT expression between tumor and healthy tissue. Multidrug resistance coordinated with glucuronidation has also been described here for drugs used in the management of epilepsy, psychiatric diseases, HIV infections, hypertension and hypercholesterolemia. Proposals to reverse UGT-mediated drug resistance should consider the endogenous functions of UGT.
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Affiliation(s)
- Zofia Mazerska
- Gdańsk University of Technology, Chemical Faculty, Department of Pharmaceutical Technology and Biochemistry, 80-233 Gdańsk, Poland
| | - Anna Mróz
- Gdańsk University of Technology, Chemical Faculty, Department of Pharmaceutical Technology and Biochemistry, 80-233 Gdańsk, Poland
| | - Monika Pawłowska
- Gdańsk University of Technology, Chemical Faculty, Department of Pharmaceutical Technology and Biochemistry, 80-233 Gdańsk, Poland
| | - Ewa Augustin
- Gdańsk University of Technology, Chemical Faculty, Department of Pharmaceutical Technology and Biochemistry, 80-233 Gdańsk, Poland.
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Zhou Q, Lavorgna A, Bowman M, Hiscott J, Harhaj EW. Aryl Hydrocarbon Receptor Interacting Protein Targets IRF7 to Suppress Antiviral Signaling and the Induction of Type I Interferon. J Biol Chem 2015; 290:14729-39. [PMID: 25911105 DOI: 10.1074/jbc.m114.633065] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Indexed: 12/25/2022] Open
Abstract
The transcription factor IRF7 (interferon regulatory factor 7) is a key regulator of type I interferon and plays essential roles in restricting virus infection and spread. IRF7 activation is tightly regulated to prevent excessive inflammation and autoimmunity; however, how IRF7 is suppressed by negative regulators remains poorly understood. Here, we have identified AIP (aryl hydrocarbon receptor interacting protein) as a new binding partner of IRF7. The interaction between AIP and IRF7 is enhanced upon virus infection, and AIP potently inhibits IRF7-induced type I IFN (IFNα/β) production. Overexpression of AIP blocks virus-induced activation of IFN, whereas knockdown of AIP by siRNA potentiates virally activated IFN production. Consistently, AIP-deficient murine embryonic fibroblasts are highly resistant to virus infection because of increased production of IFNα/β. AIP inhibits IRF7 function by antagonizing the nuclear localization of IRF7. Together, our study identifies AIP as a novel inhibitor of IRF7 and a negative regulator of innate antiviral signaling.
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Affiliation(s)
- Qinjie Zhou
- From the Department of Microbiology and Immunology, The University of Miami, Miller School of Medicine, Miami, Florida 33136
| | - Alfonso Lavorgna
- the Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland 21287
| | - Melissa Bowman
- the Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland 21287, the Graduate Program in Cellular and Molecular Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, and
| | - John Hiscott
- the Division of Infectious Diseases, Vaccine & Gene Therapy Institute of Florida, Port Saint Lucie, Florida 34987
| | - Edward W Harhaj
- the Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland 21287,
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Guy NC, Garcia YA, Sivils JC, Galigniana MD, Cox MB. Functions of the Hsp90-binding FKBP immunophilins. Subcell Biochem 2015; 78:35-68. [PMID: 25487015 DOI: 10.1007/978-3-319-11731-7_2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Hsp90 functionally interacts with a broad array of client proteins, but in every case examined Hsp90 is accompanied by one or more co-chaperones. One class of co-chaperone contains a tetratricopeptide repeat domain that targets the co-chaperone to the C-terminal region of Hsp90. Within this class are Hsp90-binding peptidylprolyl isomerases, most of which belong to the FK506-binding protein (FKBP) family. Despite the common association of FKBP co-chaperones with Hsp90, it is now clear that the client protein influences, and is influenced by, the particular FKBP bound to Hsp90. Examples include Xap2 in aryl hydrocarbon receptor complexes and FKBP52 in steroid receptor complexes. In this chapter, we discuss the known functional roles played by FKBP co-chaperones and, where possible, relate distinctive functions to structural differences between FKBP members.
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Affiliation(s)
- Naihsuan C Guy
- Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, 79968, El Paso, TX, USA,
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Lecoq AL, Kamenický P, Guiochon-Mantel A, Chanson P. Genetic mutations in sporadic pituitary adenomas--what to screen for? Nat Rev Endocrinol 2015; 11:43-54. [PMID: 25350067 DOI: 10.1038/nrendo.2014.181] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Pituitary adenomas are benign intracranial neoplasms that can result in morbidity owing to local invasion and/or excessive or deficient hormone production. The prevalence of symptomatic pituitary adenomas is approximately 1:1,000 in the general population. The vast majority of these tumours occur sporadically and are not part of syndromic disorders. However, germline mutations in genes known to predispose individuals to familial pituitary adenomas are found in a few patients with sporadic pituitary adenomas. Mutations in AIP (encoding aryl-hydrocarbon receptor-interacting protein) are the most frequently observed germline mutations. The prevalence of these mutations in patients with sporadic pituitary adenomas is ∼4%, but can increase to 8-20% in young adults with macroadenomas or gigantism, and also in children. Germline mutations in MEN1 (encoding menin) result in multiple endocrine neoplasia type 1 and are found in very young patients with isolated sporadic pituitary adenomas, which highlights the importance of the chromosome 11q13 locus in pituitary tumorigenesis. In this Review, we describe the clinical features of patients with sporadic pituitary adenomas that are associated with AIP or MEN1 mutations, and discuss the molecular mechanisms that might be involved in pituitary adenoma tumorigenesis. We also discuss genetic screening of patients with sporadic pituitary adenomas and investigations of relatives of these patients who also have the same genetic mutations.
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Affiliation(s)
- Anne-Lise Lecoq
- Service d'Endocrinologie et des Maladies de la Reproduction, AP-HP, Hôpitaux Universitaires Paris-Sud (site Bicêtre), 78 Rue du Général Leclerc, 94270 Le Kremlin-Bicêtre, France
| | - Peter Kamenický
- Service d'Endocrinologie et des Maladies de la Reproduction, AP-HP, Hôpitaux Universitaires Paris-Sud (site Bicêtre), 78 Rue du Général Leclerc, 94270 Le Kremlin-Bicêtre, France
| | - Anne Guiochon-Mantel
- Laboratoire de Génétique Moléculaire, Pharmacogénétique et Hormonologie, AP-HP, Hôpitaux Universitaires Paris-Sud (site Bicêtre), 78 Rue du Général Leclerc, 94270 Le Kremlin-Bicêtre, France
| | - Philippe Chanson
- Service d'Endocrinologie et des Maladies de la Reproduction, AP-HP, Hôpitaux Universitaires Paris-Sud (site Bicêtre), 78 Rue du Général Leclerc, 94270 Le Kremlin-Bicêtre, France
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Schimmack G, Eitelhuber AC, Vincendeau M, Demski K, Shinohara H, Kurosaki T, Krappmann D. AIP augments CARMA1-BCL10-MALT1 complex formation to facilitate NF-κB signaling upon T cell activation. Cell Commun Signal 2014; 12:49. [PMID: 25245034 PMCID: PMC4222456 DOI: 10.1186/s12964-014-0049-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 07/15/2014] [Indexed: 11/11/2022] Open
Abstract
Background The CARMA1-BCL10-MALT1 (CBM) complex bridges T cell receptor (TCR) signaling to the canonical IκB kinase (IKK)/NF-κB pathway. The CBM complex constitutes a signaling cluster of more than 1 Mio Dalton. Little is known about factors that facilitate the rapid assembly and maintenance of this dynamic higher order complex. Findings Here, we report the novel interaction of the aryl hydrocarbon receptor (AHR) interacting protein (AIP) and the molecular scaffold protein CARMA1. In T cells, transient binding of CARMA1 and AIP enhanced formation of the CBM complex. Thereby, AIP promoted optimal IKK/NF-κB signaling and IL-2 production in response to TCR/CD28 co-stimulation. Conclusions Our data demonstrate that AIP acts as a positive regulator of NF-κB signaling upon T cell activation.
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Endler A, Chen L, Shibasaki F. Coactivator recruitment of AhR/ARNT1. Int J Mol Sci 2014; 15:11100-10. [PMID: 24950180 PMCID: PMC4100201 DOI: 10.3390/ijms150611100] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 05/27/2014] [Accepted: 06/07/2014] [Indexed: 01/03/2023] Open
Abstract
A common feature of nuclear receptors (NRs) is the transformation of external cell signals into specific transcriptions of the signal molecule. Signal molecules function as ligands for NRs and, after their uptake, activated NRs form homo- or heterodimers at promoter recognition sequences of the specific genes in the nucleus. Another common feature of NRs is their dependence on coactivators, which bridge the basic transcriptional machinery and other cofactors to the target genes, in order to initiate transcription and to unwind histone-bound DNA for exposing additional promoter recognition sites via their histone acetyltransferase (HAT) function. In this review, we focus on our recent findings related to the recruitment of steroid receptor coactivator 1 (SRC1/NCoA1) by the estrogen receptor-α (ERα) and by the arylhydrocarbon receptor/arylhydrocarbon receptor nuclear translocator 1 (AhR/ARNT1) complex. We also describe the extension of our previously published findings regarding the binding between ARNT1.1 exon16 and SRC1e exon 21, via in silico analyses of androgen receptor (AR) NH2-carboxyl-terminal interactions, the results of which were verified by in vitro experiments. Based on these data, we suggest a newly derived tentative binding site of nuclear coactivator 2/glucocorticoid receptor interacting protein-1/transcriptional intermediary factor 2 (NCOA-2/ GRIP-1/TIF-2) for ARNT1.1 exon 16. Furthermore, results obtained by immunoprecipitation have revealed a second leucine-rich binding site for hARNT1.1 exon 16 in SRC1e exon 21 (LSSTDLL). Finally, we discuss the role of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as an endocrine disruptor for estrogen related transcription.
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Affiliation(s)
- Alexander Endler
- Department of Molecular Medical Research, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Li Chen
- Department of Molecular Medical Research, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Futoshi Shibasaki
- Department of Molecular Medical Research, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
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Abstract
Pituitary adenomas are benign intracranial neoplasms that present a major clinical concern due to hormone overproduction and/or tumor mass effects. The majority of pituitary adenomas occur sporadically; however, familial cases are increasingly being recognized, such as multiple endocrine neoplasia type 1 (MEN1), Carney complex (CNC), and familial isolated pituitary adenoma (FIPA). Familial pituitary tumors appear to differ from their sporadic counterparts both in their genetic basis and in clinical characteristics. Evidence suggests that, especially in MEN1 and FIPA, tumors are more aggressive and affect patients at a younger age, therefore justifying the importance of early diagnosis, while in Carney complex pituitary hyperplasia is common. The genetic alterations responsible for the formation of familial pituitary syndromes include the MEN1 gene, responsible for about 80% of MEN1 cases, the regulatory subunit of the protein kinase A, PRKAR1A, responsible for about 70% of Carney complex cases, and AIP, the gene coding the aryl hydrocarbon receptor interacting protein, responsible for about 20% of FIPA cases. Rarely other genes have also been found responsible for familial pituitary adenoma cases. McCune-Albright syndrome (MAS) also has a genetic origin due to mosaic mutations in the G protein-coupled α subunit coded by the GNAS1 gene. In this chapter, we summarize the genetic and clinical characteristics of these familial pituitary syndromes and MAS.
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Affiliation(s)
- Neda Alband
- Department of Endocrinology, Barts and the London School of Medicine, Queen Mary University of London, London, UK
| | - Márta Korbonits
- Department of Endocrinology, Barts and the London School of Medicine, Queen Mary University of London, London, UK.
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Tappenden DM, Hwang HJ, Yang L, Thomas RS, LaPres JJ. The Aryl-Hydrocarbon Receptor Protein Interaction Network (AHR-PIN) as Identified by Tandem Affinity Purification (TAP) and Mass Spectrometry. J Toxicol 2013; 2013:279829. [PMID: 24454361 PMCID: PMC3870133 DOI: 10.1155/2013/279829] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/09/2013] [Accepted: 10/14/2013] [Indexed: 12/28/2022] Open
Abstract
The aryl-hydrocarbon receptor (AHR), a ligand activated PAS superfamily transcription factor, mediates most, if not all, of the toxicity induced upon exposure to various dioxins, dibenzofurans, and planar polyhalogenated biphenyls. While AHR-mediated gene regulation plays a central role in the toxic response to dioxin exposure, a comprehensive understanding of AHR biology remains elusive. AHR-mediated signaling starts in the cytoplasm, where the receptor can be found in a complex with the heat shock protein of 90 kDa (Hsp90) and the immunophilin-like protein, aryl-hydrocarbon receptor-interacting protein (AIP). The role these chaperones and other putative interactors of the AHR play in the toxic response is not known. To more comprehensively define the AHR-protein interaction network (AHR-PIN) and identify other potential pathways involved in the toxic response, a proteomic approach was undertaken. Using tandem affinity purification (TAP) and mass spectrometry we have identified several novel protein interactions with the AHR. These interactions physically link the AHR to proteins involved in the immune and cellular stress responses, gene regulation not mediated directly via the traditional AHR:ARNT heterodimer, and mitochondrial function. This new insight into the AHR signaling network identifies possible secondary signaling pathways involved in xenobiotic-induced toxicity.
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Affiliation(s)
- Dorothy M. Tappenden
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824-1319, USA
- Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824-1319, USA
| | - Hye Jin Hwang
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824-1319, USA
- Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI 48824-1319, USA
| | - Longlong Yang
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709, USA
| | - Russell S. Thomas
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709, USA
| | - John J. LaPres
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824-1319, USA
- Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824-1319, USA
- Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI 48824-1319, USA
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Galat A. Functional diversity and pharmacological profiles of the FKBPs and their complexes with small natural ligands. Cell Mol Life Sci 2013; 70:3243-75. [PMID: 23224428 PMCID: PMC11113493 DOI: 10.1007/s00018-012-1206-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 10/24/2012] [Accepted: 10/25/2012] [Indexed: 12/25/2022]
Abstract
From 5 to 12 FK506-binding proteins (FKBPs) are encoded in the genomes of disparate marine organisms, which appeared at the dawn of evolutionary events giving rise to primordial multicellular organisms with elaborated internal body plan. Fifteen FKBPs, several FKBP-like proteins and some splicing variants of them are expressed in humans. Human FKBP12 and some of its paralogues bind to different macrocyclic antibiotics such as FK506 or rapamycin and their derivatives. FKBP12/(macrocyclic antibiotic) complexes induce diverse pharmacological activities such as immunosuppression in humans, anticancerous actions and as sustainers of quiescence in certain organisms. Since the FKBPs bind to various assemblies of proteins and other intracellular components, their complexes with the immunosuppressive drugs may differentially perturb miscellaneous cellular functions. Sequence-structure relationships and pharmacological profiles of diverse FKBPs and their involvement in crucial intracellular signalization pathways and modulation of cryptic intercellular communication networks were discussed.
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Affiliation(s)
- Andrzej Galat
- Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, Institut de Biologie et de Technologies de Saclay, Service d'Ingénierie Moléculaire des Protéines, Bat. 152, 91191, Gif-sur-Yvette Cedex, France.
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Busbee PB, Rouse M, Nagarkatti M, Nagarkatti PS. Use of natural AhR ligands as potential therapeutic modalities against inflammatory disorders. Nutr Rev 2013; 71:353-69. [PMID: 23731446 DOI: 10.1111/nure.12024] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The aim of this review is to discuss research involving ligands for the aryl hydrocarbon receptor (AhR) and their role in immunomodulation. While activation of the AhR is well known for its ability to regulate the biochemical and toxic effects of environmental chemicals, more recently an exciting discovery has been made indicating that AhR ligation can also regulate T-cell differentiation, specifically through activation of Foxp3(+) regulatory T cells (Tregs) and downregulation of the proinflammatory Th17 cells. Such findings have opened new avenues of research on the possibility of targeting the AhR to treat inflammatory and autoimmune diseases. Specifically, this review will discuss the current research involving natural and dietary AhR ligands. In addition, evidence indicating the potential use of these ligands in regulating inflammation in various diseases will be highlighted. The importance of the AhR in immunological processes can be illustrated by expression of this receptor on a majority of immune cell types. In addition, AhR signaling pathways have been reported to influence a number of genes responsible for mediating inflammation and other immune responses. As interest in the AhR and its ligands increases, it seems prudent to consolidate current research on the contributions of these ligands to immune regulation during the course of inflammatory diseases.
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Affiliation(s)
- Philip B Busbee
- Department of Pathology, Microbiology, and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina 29208, USA
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43
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Beckers A, Aaltonen LA, Daly AF, Karhu A. Familial isolated pituitary adenomas (FIPA) and the pituitary adenoma predisposition due to mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene. Endocr Rev 2013; 34:239-77. [PMID: 23371967 PMCID: PMC3610678 DOI: 10.1210/er.2012-1013] [Citation(s) in RCA: 194] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Pituitary adenomas are one of the most frequent intracranial tumors and occur with a prevalence of approximately 1:1000 in the developed world. Pituitary adenomas have a serious disease burden, and their management involves neurosurgery, biological therapies, and radiotherapy. Early diagnosis of pituitary tumors while they are smaller may help increase cure rates. Few genetic predictors of pituitary adenoma development exist. Recent years have seen two separate, complimentary advances in inherited pituitary tumor research. The clinical condition of familial isolated pituitary adenomas (FIPA) has been described, which encompasses the familial occurrence of isolated pituitary adenomas outside of the setting of syndromic conditions like multiple endocrine neoplasia type 1 and Carney complex. FIPA families comprise approximately 2% of pituitary adenomas and represent a clinical entity with homogeneous or heterogeneous pituitary adenoma types occurring within the same kindred. The aryl hydrocarbon receptor interacting protein (AIP) gene has been identified as causing a pituitary adenoma predisposition of variable penetrance that accounts for 20% of FIPA families. Germline AIP mutations have been shown to associate with the occurrence of large pituitary adenomas that occur at a young age, predominantly in children/adolescents and young adults. AIP mutations are usually associated with somatotropinomas, but prolactinomas, nonfunctioning pituitary adenomas, Cushing disease, and other infrequent clinical adenoma types can also occur. Gigantism is a particular feature of AIP mutations and occurs in more than one third of affected somatotropinoma patients. Study of pituitary adenoma patients with AIP mutations has demonstrated that these cases raise clinical challenges to successful treatment. Extensive research on the biology of AIP and new advances in mouse Aip knockout models demonstrate multiple pathways by which AIP may contribute to tumorigenesis. This review assesses the current clinical and therapeutic characteristics of more than 200 FIPA families and addresses research findings among AIP mutation-bearing patients in different populations with pituitary adenomas.
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Affiliation(s)
- Albert Beckers
- Department of Endocrinology, Centre Hospitalier Universitaire de Liège, University of Liège, Domaine Universitaire du Sart-Tilman, 4000 Liège, Belgium.
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Wilson SR, Joshi AD, Elferink CJ. The tumor suppressor Kruppel-like factor 6 is a novel aryl hydrocarbon receptor DNA binding partner. J Pharmacol Exp Ther 2013; 345:419-29. [PMID: 23512538 DOI: 10.1124/jpet.113.203786] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-mediated basic helix-loop-helix transcription factor of the Per/Arnt/Sim family that regulates adaptive and toxic responses to a variety of chemical pollutants, including polycyclic aromatic hydrocarbons and halogenated aromatic hydrocarbons, most notably 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Ligand activation leads to AhR nuclear translocation and binding to a xenobiotic response element (XRE) in association with the Arnt to regulate gene expression. Several recent genome-wide transcriptional studies identified numerous AhR target genes that lack the canonical XRE recognition site in the promoter regions. Characterization of one such target gene, the plasminogen activator inhibitor 1, identified a novel nonconsensus XRE (NC-XRE) that confers TCDD responsiveness independently of the Arnt protein. Studies reported here show that the NC-XRE is a recognition site for the AhR and a new binding partner, the Kruppel-like factor (KLF) family member KLF6. In vivo chromatin immunoprecipitations and in vitro DNA binding studies demonstrate that the AhR and KLF6 proteins form an obligatory heterodimer necessary for NC-XRE binding. Mutational analyses show that the protein-protein interactions involve the AhR C terminus and KLF6 N terminus, respectively. Moreover, NC-XRE binding depends on the 5' basic region in KLF6 rather than the previously characterized zinc finger DNA binding domain. Collectively, the results unmask a novel AhR signaling mechanism distinct from the canonical XRE-driven process that will enrich our future understanding of AhR biology.
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Affiliation(s)
- Shelly R Wilson
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX, USA
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Linnert M, Lin YJ, Manns A, Haupt K, Paschke AK, Fischer G, Weiwad M, Lücke C. The FKBP-type domain of the human aryl hydrocarbon receptor-interacting protein reveals an unusual Hsp90 interaction. Biochemistry 2013; 52:2097-107. [PMID: 23418784 DOI: 10.1021/bi301649m] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The aryl hydrocarbon receptor-interacting protein (AIP) has been predicted to consist of an N-terminal FKBP-type peptidyl-prolyl cis/trans isomerase (PPIase) domain and a C-terminal tetratricopeptide repeat (TPR) domain, as typically found in FK506-binding immunophilins. AIP, however, exhibited no inherent FK506 binding or PPIase activity. Alignment with the prototypic FKBP12 showed a high sequence homology but indicated inconsistencies with regard to the secondary structure prediction derived from chemical shift analysis of AIP(2-166). NMR-based structure determination of AIP(2-166) now revealed a typical FKBP fold with five antiparallel β-strands forming a half β-barrel wrapped around a central α-helix, thus permitting AIP to be also named FKBP37.7 according to FKBP nomenclature. This PPIase domain, however, features two structure elements that are unusual for FKBPs: (i) an N-terminal α-helix, which additionally stabilizes the domain, and (ii) a rather long insert, which connects the last two β-strands and covers the putative active site. Diminution of the latter insert did not generate PPIase activity or FK506 binding capability, indicating that the lack of catalytic activity in AIP is the result of structural differences within the PPIase domain. Compared to active FKBPs, a diverging conformation of the loop connecting β-strand C' and the central α-helix apparently is responsible for this inherent lack of catalytic activity in AIP. Moreover, Hsp90 was identified as potential physiological interaction partner of AIP, which revealed binding contacts not only at the TPR domain but uncommonly also at the PPIase domain.
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Affiliation(s)
- Miriam Linnert
- Max Planck Research Unit for Enzymology of Protein Folding , Weinbergweg 22, 06120 Halle (Saale), Germany
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Morgan RML, Hernández-Ramírez LC, Trivellin G, Zhou L, Roe SM, Korbonits M, Prodromou C. Structure of the TPR domain of AIP: lack of client protein interaction with the C-terminal α-7 helix of the TPR domain of AIP is sufficient for pituitary adenoma predisposition. PLoS One 2012; 7:e53339. [PMID: 23300914 PMCID: PMC3534021 DOI: 10.1371/journal.pone.0053339] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 11/27/2012] [Indexed: 12/22/2022] Open
Abstract
Mutations of the aryl hydrocarbon receptor interacting protein (AIP) have been associated with familial isolated pituitary adenomas predisposing to young-onset acromegaly and gigantism. The precise tumorigenic mechanism is not well understood as AIP interacts with a large number of independent proteins as well as three chaperone systems, HSP90, HSP70 and TOMM20. We have determined the structure of the TPR domain of AIP at high resolution, which has allowed a detailed analysis of how disease-associated mutations impact on the structural integrity of the TPR domain. A subset of C-terminal α-7 helix (Cα-7h) mutations, R304* (nonsense mutation), R304Q, Q307* and R325Q, a known site for AhR and PDE4A5 client-protein interaction, occur beyond those that interact with the conserved MEEVD and EDDVE sequences of HSP90 and TOMM20. These C-terminal AIP mutations appear to only disrupt client-protein binding to the Cα-7h, while chaperone binding remains unaffected, suggesting that failure of client-protein interaction with the Cα-7h is sufficient to predispose to pituitary adenoma. We have also identified a molecular switch in the AIP TPR-domain that allows recognition of both the conserved HSP90 motif, MEEVD, and the equivalent sequence (EDDVE) of TOMM20.
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Affiliation(s)
- Rhodri M. L. Morgan
- Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Laura C. Hernández-Ramírez
- Department of Endocrinology, Barts and the London School of Medicine, Queen Mary University of London, London, United Kingdom
| | - Giampaolo Trivellin
- Department of Endocrinology, Barts and the London School of Medicine, Queen Mary University of London, London, United Kingdom
| | - Lihong Zhou
- Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - S. Mark Roe
- Biochemistry and Molecular Biology, Chichester 2, University of Sussex, Brighton, United Kingdom
| | - Márta Korbonits
- Department of Endocrinology, Barts and the London School of Medicine, Queen Mary University of London, London, United Kingdom
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Linnert M, Haupt K, Lin YJ, Kissing S, Paschke AK, Fischer G, Weiwad M, Lücke C. NMR assignments of the FKBP-type PPIase domain of the human aryl-hydrocarbon receptor-interacting protein (AIP). BIOMOLECULAR NMR ASSIGNMENTS 2012; 6:209-212. [PMID: 22287093 DOI: 10.1007/s12104-012-9359-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 01/17/2012] [Indexed: 05/31/2023]
Abstract
The aryl-hydrocarbon receptor-interacting protein (AIP) interacts with several protein binding partners and has been associated with pituitary tumor development. Here, we report nearly complete (1)H, (13)C and (15)N chemical shift assignments for the N-terminal AIP(2-166) segment, which has been predicted to represent a FKBP-type PPIase domain. Sequence alignment with the prototypic FKBP12, however, reveals disagreements between the AIP chemical shift index consensus and the corresponding FKBP12 secondary structure elements.
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Affiliation(s)
- Miriam Linnert
- Max Planck Research Unit for Enzymology of Protein Folding, Weinbergweg 22, 06120 Halle (Saale), Germany
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Xing Y, Nukaya M, Satyshur KA, Jiang L, Stanevich V, Korkmaz EN, Burdette L, Kennedy GD, Cui Q, Bradfield CA. Identification of the Ah-receptor structural determinants for ligand preferences. Toxicol Sci 2012; 129:86-97. [PMID: 22659362 DOI: 10.1093/toxsci/kfs194] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a transcription factor that responds to diverse ligands and plays a critical role in toxicology, immune function, and cardiovascular physiology. The structural basis of the AHR for ligand promiscuity and preferences is critical for understanding AHR function. Based on the structure of a closely related protein HIF2α, we modeled the AHR ligand binding domain (LBD) bound to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and benzo(a)pyrene (BaP) and identified residues that control ligand preferences by shape and H-bond potential. Mutations to these residues, particularly Q377 and G298, resulted in robust and opposite changes in the potency of TCDD and BaP and up to a 20-fold change in the ratio of TCDD/BaP efficacy. The model also revealed a flexible "belt" structure; molecular dynamic (MD) simulation suggested that the "belt" and several other structural elements in the AHR-LBD are more flexible than HIF2α and likely contribute to ligand promiscuity. Molecular docking of TCDD congeners to a model of human AHR-LBD ranks their binding affinity similar to experimental ranking of their toxicity. Our study reveals key structural basis for prediction of toxicity and understanding the AHR signaling through diverse ligands.
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Affiliation(s)
- Yongna Xing
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin 53706, USA.
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Mehta V, Vezina CM. Potential protective mechanisms of aryl hydrocarbon receptor (AHR) signaling in benign prostatic hyperplasia. Differentiation 2012; 82:211-9. [PMID: 21684673 DOI: 10.1016/j.diff.2011.05.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 05/20/2011] [Accepted: 05/27/2011] [Indexed: 11/17/2022]
Abstract
The aryl hydrocarbon receptor (AHR) is an evolutionarily conserved ligand activated transcription factor best known for its role in mediating toxic responses to dioxin-like environmental contaminants. However, AHR signaling has also emerged as an active participant in processes of normal development and disease progression. Here, we review the role of AHR signaling in prostate development and disease processes, with a particular emphasis on benign prostatic hyperplasia (BPH). Inappropriate AHR activation has recently been associated with a decreased risk of symptomatic BPH in humans and has been shown to impair prostate development and disrupt endocrine signaling in rodents. We highlight known physiological responses to AHR activation in prostate and other tissues and discuss potential mechanisms by which it may act in adult human prostate to protect against symptomatic BPH.
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Affiliation(s)
- Vatsal Mehta
- Department of Comparative Biosciences, University of Wisconsin, 1656 Linden Drive, Madison, WI 53706, USA
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50
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Zhang N. The role of endogenous aryl hydrocarbon receptor signaling in cardiovascular physiology. J Cardiovasc Dis Res 2011; 2:91-5. [PMID: 21814412 PMCID: PMC3144625 DOI: 10.4103/0975-3583.83033] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is an orphan nuclear receptor with a primary function of mediating xenobiotic metabolism through transcriptional activation of Phase I and Phase II drug-metabolizing enzymes. Although no high-affinity physiological activators of AHR have been discovered, the endogenous signaling of the AHR pathway is believed to play an important role in the development and function of the cardiovascular system, based on the observations on ahr gene-deficient mice. The AHR knockout mice develop cardiac hypertrophy, abnormal vascular structure in multiple organs and altered blood pressure depending on their host environment. In this review, the endogenous role of AHR in cardiovascular physiology, including heart function, vascular development and blood pressure regulation has been summarized and discussed.
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Affiliation(s)
- Nan Zhang
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan Medical School, USA
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