1
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Wang R, Yue X, Zhu J, Hu R, Li Y, Yang Y, Liu M. Mutation of two residues converts the ligand-binding domain of RXRα into a uniform monomer without impairing the binding of retinoic acid and cofactors. Biochem Biophys Res Commun 2023; 642:50-56. [PMID: 36563628 DOI: 10.1016/j.bbrc.2022.12.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Retinoid X receptor (RXRα) is a nuclear receptor (NR) for retinoic acid (RA) and regulates various NR signaling pathways. Ligand-binding domain (LBD) of RXRα can bind with its ligand 9-cis-RA and cofactors, and mediate the forming of homodimer and homotetramer of RXRα and its heterodimer with other NRs, conferring RXRα the ability to play complicated roles in development and diseases. Due to the coexistence of monomer, dimer and tetramer, there are difficulties to study the structure and interaction of RXRα-LBD with its ligands and cofactors in solution and to distinguish the roles of different forms of RXRα in cell. Here, through analyzing available structures of RXRα-LBD, we selected two residues, D379 and L420, in the homodimer interface to design three mutants of RXRα-LBD. Recombinant proteins of the three mutants showed decreased proportions of dimer and tetramer but unchanged overall structure and binding affinities to 9-cis-RA, corepressor SMRT, and coactivator SRC2. Especially, the double-site mutant RXRα-LBDD379A-L420G existed as a uniform monomer. Furthermore, L420 was found to play a similar role in forming RXRα-LBD homodimer and its heterodimer with various NRs, while the role of D379 varies a lot, as it shows almost no interaction with RARα/β, LXRα/β, and THRα/β. This study provides a new insight into the mechanism for forming RXRα-LBD homodimer and its heterodimer with other NRs, and will facilitate the studies on the structure and interaction of RXRα-LBD with ligands, cofactors and drugs in solution, and the broad physiological functions of RXRα cooperating with various NRs in cell.
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Affiliation(s)
- Ru Wang
- Department of Chemistry, College of Science, Huazhong Agricultural University, Wuhan, 430070, China; State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences - Wuhan National Laboratory for Optoelectronics, Wuhan, 430071, China
| | - Xiali Yue
- Department of Chemistry, College of Science, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Jiang Zhu
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences - Wuhan National Laboratory for Optoelectronics, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Rui Hu
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences - Wuhan National Laboratory for Optoelectronics, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ying Li
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences - Wuhan National Laboratory for Optoelectronics, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yunhuang Yang
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences - Wuhan National Laboratory for Optoelectronics, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Maili Liu
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences - Wuhan National Laboratory for Optoelectronics, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
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2
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Willems S, Zaienne D, Merk D. Targeting Nuclear Receptors in Neurodegeneration and Neuroinflammation. J Med Chem 2021; 64:9592-9638. [PMID: 34251209 DOI: 10.1021/acs.jmedchem.1c00186] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nuclear receptors, also known as ligand-activated transcription factors, regulate gene expression upon ligand signals and present as attractive therapeutic targets especially in chronic diseases. Despite the therapeutic relevance of some nuclear receptors in various pathologies, their potential in neurodegeneration and neuroinflammation is insufficiently established. This perspective gathers preclinical and clinical data for a potential role of individual nuclear receptors as future targets in Alzheimer's disease, Parkinson's disease, and multiple sclerosis, and concomitantly evaluates the level of medicinal chemistry targeting these proteins. Considerable evidence suggests the high promise of ligand-activated transcription factors to counteract neurodegenerative diseases with a particularly high potential of several orphan nuclear receptors. However, potent tools are lacking for orphan receptors, and limited central nervous system exposure or insufficient selectivity also compromises the suitability of well-studied nuclear receptor ligands for functional studies. Medicinal chemistry efforts are needed to develop dedicated high-quality tool compounds for the therapeutic validation of nuclear receptors in neurodegenerative pathologies.
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Affiliation(s)
- Sabine Willems
- Institute of Pharmaceutical Chemistry, Goethe University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany
| | - Daniel Zaienne
- Institute of Pharmaceutical Chemistry, Goethe University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany
| | - Daniel Merk
- Institute of Pharmaceutical Chemistry, Goethe University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany
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3
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Shao M, Lu L, Wang Q, Ma L, Tian X, Li C, Li C, Guo D, Wang Q, Wang W, Wang Y. The multi-faceted role of retinoid X receptor in cardiovascular diseases. Biomed Pharmacother 2021; 137:111264. [PMID: 33761589 DOI: 10.1016/j.biopha.2021.111264] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/04/2021] [Accepted: 01/07/2021] [Indexed: 01/14/2023] Open
Abstract
Retinoid X receptors (RXRs) are members of ligand-dependent transcription factors whose effects on a diversity of cellular processes, including cellular proliferation, the immune response, and lipid and glucose metabolism. Knock out of RXRα causes a hypoplasia of the myocardium which is lethal during fetal life. In addition, the heart maintains a well-orchestrated balances in utilizing fatty acids (FAs) and other substrates to meet the high energy requirements. As the master transcriptional regulators of lipid metabolism, RXRs become particularly important for the energy needs of the heart. Accumulating evidence suggested that RXRs may exert direct beneficial effects in the heart both through heterodimerization with other nuclear receptors (NRs) and homodimerization, thus standing as suitable targets for treating in cardiovascular diseases. Although compounds that target RXRs are promising drugs, their use is limited by toxicity. A better understanding of the structural biology of RXRs in cardiovascular disease should enable the rational design of more selective nuclear receptor modulators to overcome these problems. Here, this review summarizes a brief overview of RXRs structure and versatility of RXR action in the control of cardiovascular diseases. And we also discussed the therapeutic potential of RXR ligand.
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Affiliation(s)
- Mingyan Shao
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Linghui Lu
- College of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Qian Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Lin Ma
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Xue Tian
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Changxiang Li
- College of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Chun Li
- Modern Research Center of Traditional Chinese Medicine, School of Traditional Chinese Material Medica, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Dongqing Guo
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Qiyan Wang
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Wei Wang
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China.
| | - Yong Wang
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China; College of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China.
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4
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Chitranshi N, Dheer Y, Kumar S, Graham SL, Gupta V. Molecular docking, dynamics, and pharmacology studies on bexarotene as an agonist of ligand-activated transcription factors, retinoid X receptors. J Cell Biochem 2019; 120:11745-11760. [PMID: 30746761 DOI: 10.1002/jcb.28455] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/05/2018] [Accepted: 12/06/2018] [Indexed: 01/24/2023]
Abstract
Retinoid X receptors (RXRs) belong to the nuclear receptor superfamily, and upon ligand activation, these receptors control gene transcription via either homodimerization with themselves or heterodimerization with the partner-nuclear receptor. The protective effects of RXRs and RXR agonists have been reported in several neurodegenerative diseases, including in the retina. This study was aimed to prioritize compounds from natural and synthetic origin retinoids as potential RXR agonists by molecular docking and molecular dynamic simulation strategies. The docking studies indicated bexarotene as a lead compound that can activate various RXR receptor isoforms (α, β, and γ) and has a strong binding affinity to the receptor protein than retinoic acid, which is known as a natural endogenous RXR agonist. Dynamic simulation studies confirmed that the hydrogen bonding and hydrophobic interactions were highly stable in all the three isoforms of the RXR-bexarotene complex. To further validate the significance of the RXR receptor in neurons, in vitro pharmacological treatment of neuronal SH-SY5Y cells with bexarotene was performed. In vitro data from SH-SY5Y cells confirmed that bexarotene activated RXR-simulated neurite outgrowth significantly. We conclude that bexarotene could be potentially used as an exogenous activator of RXRs and emerge as a good drug target for several neurodegenerative disorders.
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Affiliation(s)
- Nitin Chitranshi
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales
| | - Yogita Dheer
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales
| | - Sanjay Kumar
- Bioinformatics Centre, Biotech Park, Jankipuram, Lucknow, Uttar Pradesh, India
| | - Stuart L Graham
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales
- Save Sight Institute, Sydney University, Sydney, New South Wales, Australia
| | - Vivek Gupta
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales
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5
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Esteban J, Serrano-Maciá M, Sánchez-Pérez I, Alonso-Magdalena P, Pellín MDLC, García-Arévalo M, Nadal Á, Barril J. In utero exposure to bisphenol-A disrupts key elements of retinoid system in male mice offspring. Food Chem Toxicol 2019; 126:142-151. [PMID: 30790712 DOI: 10.1016/j.fct.2019.02.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/08/2019] [Accepted: 02/09/2019] [Indexed: 12/19/2022]
Abstract
The retinoid system controls essential cellular processes including mitosis, differentiation and metabolism among others. Although the retinoid-signalling pathway is a potential target for the action of several endocrine disrupting chemicals (EDCs), the information about the developmental effects of bisphenol-A (BPA) on the hepatic retinoid system is scarce. Herein, male mice were in utero exposed to BPA following maternal subcutaneous doses of 0, 10 and 100 μg/kg bw/day from gestational day 9-16 and they were sacrificed at post-natal day 30. Retinoid concentrations and gene expression of key elements involved in the retinoid system were determined in liver. BPA increased all-trans-retinoic acid concentration and expression of Adh1, Aox1 and Cyp1a2 (biosynthesis of retinoic acid), while reduced Mrp3 (efflux from hepatocyte to blood), increased Bcrp expression (biliary excretion) and changed the retinoid-dependent signalling system after reducing expression of Rxrβ and increasing that of Fgf21. Furthermore, we found bivariate associations of Rarγ and Rxrγ expressions with all-trans-retinoic acid concentrations and of Fgf21 expression with that of Rarγ. Those findings occurred in animals which showed altered pancreatic function and impaired glucose metabolism during adulthood. The present information should be useful for enhancing testing methods for the identification of EDCs.
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Affiliation(s)
- Javier Esteban
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche, Spain.
| | | | | | - Paloma Alonso-Magdalena
- Instituto de Biología Molecular y Celular (IBMC), Universidad Miguel Hernández de Elche, Elche, Spain; Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche, Elche, Spain; Centro de Investigación Biomédica En Red de Diabetes y Enfermedades Metabólicas Asociadas, CIBERDEM, Universidad Miguel Hernández de Elche, Elche, Spain
| | | | - Marta García-Arévalo
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche, Spain; Centro de Investigación Biomédica En Red de Diabetes y Enfermedades Metabólicas Asociadas, CIBERDEM, Universidad Miguel Hernández de Elche, Elche, Spain
| | - Ángel Nadal
- Instituto de Biología Molecular y Celular (IBMC), Universidad Miguel Hernández de Elche, Elche, Spain; Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche, Elche, Spain; Centro de Investigación Biomédica En Red de Diabetes y Enfermedades Metabólicas Asociadas, CIBERDEM, Universidad Miguel Hernández de Elche, Elche, Spain
| | - Jose Barril
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche, Spain
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6
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Pollinger J, Gellrich L, Schierle S, Kilu W, Schmidt J, Kalinowsky L, Ohrndorf J, Kaiser A, Heering J, Proschak E, Merk D. Tuning Nuclear Receptor Selectivity of Wy14,643 towards Selective Retinoid X Receptor Modulation. J Med Chem 2019; 62:2112-2126. [PMID: 30702885 DOI: 10.1021/acs.jmedchem.8b01848] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The fatty acid sensing nuclear receptor families retinoid X receptors (RXRs) and peroxisome proliferator-activated receptors (PPARs) hold therapeutic potential in neurodegeneration. Valuable pleiotropic activities of Wy14,643 in models of such conditions exceed its known PPAR agonistic profile. Here, we characterize the compound as an RXR agonist explaining the pleiotropic effects and report its systematic structure-activity relationship analysis with the discovery of specific molecular determinants driving activity on PPARs and RXRs. We have designed close analogues of the drug comprising selective and dual agonism on RXRs and PPARs that may serve as superior pharmacological tools to study the role and interplay of the nuclear receptors in various pathologies. A systematically optimized high potency RXR agonist revealed activity in vivo and active concentrations in brain. With its lack of RXR/liver X receptor-mediated side effects and superior profile compared to classical rexinoids, it establishes a new class of innovative RXR modulators to overcome key challenges in RXR targeting drug discovery.
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Affiliation(s)
- Julius Pollinger
- Institute of Pharmaceutical Chemistry , Goethe University Frankfurt , Max-von-Laue-Str. 9 , D-60438 Frankfurt , Germany
| | - Leonie Gellrich
- Institute of Pharmaceutical Chemistry , Goethe University Frankfurt , Max-von-Laue-Str. 9 , D-60438 Frankfurt , Germany
| | - Simone Schierle
- Institute of Pharmaceutical Chemistry , Goethe University Frankfurt , Max-von-Laue-Str. 9 , D-60438 Frankfurt , Germany
| | - Whitney Kilu
- Institute of Pharmaceutical Chemistry , Goethe University Frankfurt , Max-von-Laue-Str. 9 , D-60438 Frankfurt , Germany
| | - Jurema Schmidt
- Institute of Pharmaceutical Chemistry , Goethe University Frankfurt , Max-von-Laue-Str. 9 , D-60438 Frankfurt , Germany
| | - Lena Kalinowsky
- Institute of Pharmaceutical Chemistry , Goethe University Frankfurt , Max-von-Laue-Str. 9 , D-60438 Frankfurt , Germany
| | - Julia Ohrndorf
- Institute of Pharmaceutical Chemistry , Goethe University Frankfurt , Max-von-Laue-Str. 9 , D-60438 Frankfurt , Germany
| | - Astrid Kaiser
- Institute of Pharmaceutical Chemistry , Goethe University Frankfurt , Max-von-Laue-Str. 9 , D-60438 Frankfurt , Germany
| | - Jan Heering
- Project Group Translational Medicine and Pharmacology TMP , Fraunhofer IME , Theodor-Stern-Kai 7 , D-60596 Frankfurt , Germany
| | - Ewgenij Proschak
- Institute of Pharmaceutical Chemistry , Goethe University Frankfurt , Max-von-Laue-Str. 9 , D-60438 Frankfurt , Germany
| | - Daniel Merk
- Institute of Pharmaceutical Chemistry , Goethe University Frankfurt , Max-von-Laue-Str. 9 , D-60438 Frankfurt , Germany
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7
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Heitel P, Gellrich L, Kalinowsky L, Heering J, Kaiser A, Ohrndorf J, Proschak E, Merk D. Computer-Assisted Discovery and Structural Optimization of a Novel Retinoid X Receptor Agonist Chemotype. ACS Med Chem Lett 2019; 10:203-208. [PMID: 30783504 PMCID: PMC6378677 DOI: 10.1021/acsmedchemlett.8b00551] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 12/27/2018] [Indexed: 12/21/2022] Open
Abstract
As universal heterodimer partners of many nuclear receptors, the retinoid X receptors (RXRs) constitute key transcription factors. They regulate cell proliferation, differentiation, inflammation, and metabolic homeostasis and have recently been proposed as potential drug targets for neurodegenerative and inflammatory diseases. Owing to the hydrophobic nature of RXR ligand binding sites, available synthetic RXR ligands are lipophilic, and their structural diversity is limited. Here, we disclose the computer-assisted discovery of a novel RXR agonist chemotype and its systematic optimization toward potent RXR modulators. We have developed a nanomolar RXR agonist with high selectivity among nuclear receptors and superior physicochemical properties compared to classical rexinoids that appears suitable for in vivo applications and as lead for future RXR-targeting medicinal chemistry.
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Affiliation(s)
- Pascal Heitel
- Institute
of Pharmaceutical Chemistry, Goethe University
Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Leonie Gellrich
- Institute
of Pharmaceutical Chemistry, Goethe University
Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Lena Kalinowsky
- Institute
of Pharmaceutical Chemistry, Goethe University
Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Jan Heering
- Project
Group Translational Medicine and Pharmacology TMP, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Theodor-Stern-Kai 7, D-60596 Frankfurt, Germany
| | - Astrid Kaiser
- Institute
of Pharmaceutical Chemistry, Goethe University
Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Julia Ohrndorf
- Institute
of Pharmaceutical Chemistry, Goethe University
Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Ewgenij Proschak
- Institute
of Pharmaceutical Chemistry, Goethe University
Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Daniel Merk
- Institute
of Pharmaceutical Chemistry, Goethe University
Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
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8
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Osz J, McEwen AG, Wolf J, Poussin-Courmontagne P, Peluso-Iltis C, Chebaro Y, Kieffer B, Rochel N. Modulation of RXR-DNA complex assembly by DNA context. Mol Cell Endocrinol 2019; 481:44-52. [PMID: 30476562 DOI: 10.1016/j.mce.2018.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 11/15/2018] [Accepted: 11/22/2018] [Indexed: 01/16/2023]
Abstract
Retinoid X Receptors (RXRs) act as dimer partners for several nuclear receptors including itself, binding to genomic DNA response elements and regulating gene transcription with cell and gene specificity. As homodimers, RXRs bind direct repeats of the half-site (A/G)G(G/T)TCA separated by 1 nucleotide (DR1) and little variability of this consensus site is observed for natural DR1s. However, these variations are responsible of the modulation of RXR receptors function through differential binding affinity and conformational changes. To further our understanding of the molecular mechanisms underlying RXR-DNA interactions, we examined how RXR DBDs bind to different DR1s using thermodynamics, X-ray crystallography and nuclear magnetic resonance (NMR) spectroscopy. We show that the half-site sequences modulate the binding cooperativity that results from the protein-protein contacts between the two DBDs. Chemical shifts perturbation NMR experiments revealed that sequence variations in half-sites induce changes that propagate from the protein-DNA interface to the dimerization interface throughout the DBD fold.
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Affiliation(s)
- Judit Osz
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Institut National de la Santé et de la Recherche Médicale (INSERM), U1258/Centre National de la Recherche Scientifique (CNRS), UMR7104/Université de Strasbourg, 67404, Illkirch, France
| | - Alastair G McEwen
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Institut National de la Santé et de la Recherche Médicale (INSERM), U1258/Centre National de la Recherche Scientifique (CNRS), UMR7104/Université de Strasbourg, 67404, Illkirch, France
| | - Justine Wolf
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Institut National de la Santé et de la Recherche Médicale (INSERM), U1258/Centre National de la Recherche Scientifique (CNRS), UMR7104/Université de Strasbourg, 67404, Illkirch, France
| | - Pierre Poussin-Courmontagne
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Institut National de la Santé et de la Recherche Médicale (INSERM), U1258/Centre National de la Recherche Scientifique (CNRS), UMR7104/Université de Strasbourg, 67404, Illkirch, France
| | - Carole Peluso-Iltis
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Institut National de la Santé et de la Recherche Médicale (INSERM), U1258/Centre National de la Recherche Scientifique (CNRS), UMR7104/Université de Strasbourg, 67404, Illkirch, France
| | - Yassmine Chebaro
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Institut National de la Santé et de la Recherche Médicale (INSERM), U1258/Centre National de la Recherche Scientifique (CNRS), UMR7104/Université de Strasbourg, 67404, Illkirch, France
| | - Bruno Kieffer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Institut National de la Santé et de la Recherche Médicale (INSERM), U1258/Centre National de la Recherche Scientifique (CNRS), UMR7104/Université de Strasbourg, 67404, Illkirch, France.
| | - Natacha Rochel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Institut National de la Santé et de la Recherche Médicale (INSERM), U1258/Centre National de la Recherche Scientifique (CNRS), UMR7104/Université de Strasbourg, 67404, Illkirch, France.
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9
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Merk D, Grisoni F, Friedrich L, Schneider G. Tuning artificial intelligence on the de novo design of natural-product-inspired retinoid X receptor modulators. Commun Chem 2018. [DOI: 10.1038/s42004-018-0068-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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10
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Merk D, Grisoni F, Friedrich L, Gelzinyte E, Schneider G. Computer-Assisted Discovery of Retinoid X Receptor Modulating Natural Products and Isofunctional Mimetics. J Med Chem 2018; 61:5442-5447. [DOI: 10.1021/acs.jmedchem.8b00494] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Daniel Merk
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH), Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Francesca Grisoni
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH), Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza, 1, IT-20126 Milan, Italy
| | - Lukas Friedrich
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH), Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Elena Gelzinyte
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH), Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Gisbert Schneider
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH), Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
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11
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Scheepstra M, Andrei SA, de Vries RMJM, Meijer FA, Ma JN, Burstein ES, Olsson R, Ottmann C, Milroy LG, Brunsveld L. Ligand Dependent Switch from RXR Homo- to RXR-NURR1 Heterodimerization. ACS Chem Neurosci 2017; 8:2065-2077. [PMID: 28691794 PMCID: PMC5609127 DOI: 10.1021/acschemneuro.7b00216] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
![]()
Retinoid
X receptors (RXRs) play key roles in many physiological
processes in both the periphery and central nervous system. In addition,
RXRs form heterodimers with other nuclear receptors to exert their
physiological effects. The nuclear receptor related 1 protein (NURR1)
is particularly interesting because of its role in promoting differentiation
and survival of dopamine neurons. However, only a small number of
RXR-heterodimer selective modulators are available, with limited chemical
diversity. This work describes the synthesis, biochemical evaluation,
and structural elucidation of a novel series of RXR ligands with strongly
biased interactions with RXRα–NURR1 heterodimers. Targeted
modifications to the small molecule biaryl scaffold caused local RXRα
side-chain disturbances and displacement of secondary structural elements
upon ligand binding. This resulted in the repositioning of protein
helices in the heterodimer interface of RXRα, alterations in
homo- versus heterodimer formation, and modulation of activation function
2 (AF2). The data provide a rationale for the design of RXR ligands
consisting of a highly conserved hydrophilic region, strongly contributing
to the ligand affinity, and a variable hydrophobic region, which efficiently
probes the effects of structural changes at the level of the ligand
on co-regulator recruitment or the RXRα–NURR1 dimerization
interface.
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Affiliation(s)
- Marcel Scheepstra
- Department
of Biomedical Engineering and Institute for Complex Molecular Systems,
Laboratory of Chemical Biology, Technische Universiteit Eindhoven, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Sebastian A. Andrei
- Department
of Biomedical Engineering and Institute for Complex Molecular Systems,
Laboratory of Chemical Biology, Technische Universiteit Eindhoven, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Rens M. J. M. de Vries
- Department
of Biomedical Engineering and Institute for Complex Molecular Systems,
Laboratory of Chemical Biology, Technische Universiteit Eindhoven, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Femke A. Meijer
- Department
of Biomedical Engineering and Institute for Complex Molecular Systems,
Laboratory of Chemical Biology, Technische Universiteit Eindhoven, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Jian-Nong Ma
- ACADIA Pharmaceuticals
Inc., San Diego, California 92130, United States
| | - Ethan S. Burstein
- ACADIA Pharmaceuticals
Inc., San Diego, California 92130, United States
| | - Roger Olsson
- Chemical Biology & Therapeutics, Department of Experimental Medical Science, Lund University, SE-221 00 Lund, Sweden
| | - Christian Ottmann
- Department
of Biomedical Engineering and Institute for Complex Molecular Systems,
Laboratory of Chemical Biology, Technische Universiteit Eindhoven, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Lech-Gustav Milroy
- Department
of Biomedical Engineering and Institute for Complex Molecular Systems,
Laboratory of Chemical Biology, Technische Universiteit Eindhoven, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Luc Brunsveld
- Department
of Biomedical Engineering and Institute for Complex Molecular Systems,
Laboratory of Chemical Biology, Technische Universiteit Eindhoven, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
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12
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Menéndez-Gutiérrez MP, Ricote M. The multi-faceted role of retinoid X receptor in bone remodeling. Cell Mol Life Sci 2017; 74:2135-2149. [PMID: 28105491 PMCID: PMC11107715 DOI: 10.1007/s00018-017-2458-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 12/20/2016] [Accepted: 01/04/2017] [Indexed: 02/07/2023]
Abstract
Retinoid X receptors (RXRs) form a unique subclass within the nuclear receptor (NR) superfamily of ligand-dependent transcription factors. RXRs are obligatory partners for a number of other NRs, placing RXRs in a coordinating role at the crossroads of multiple signaling pathways. In addition, RXRs can function as self-sufficient homodimers. Recent advances have revealed RXRs as novel regulators of osteoclastogenesis and bone remodeling. This review outlines the versatility of RXR action in the control of transcription of bone-forming osteoblasts and bone-resorbing osteoclasts, both through heterodimerization with other NRs and through RXR homodimerization. RXR signaling is currently a major therapeutic target and, therefore, knowledge of how RXR signaling affects bone remodeling creates enormous potential for the translation of basic research findings into successful clinical therapies to increase bone mass and improve bone quality.
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Affiliation(s)
- María P Menéndez-Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - Mercedes Ricote
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain.
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13
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Nurr1:RXRα heterodimer activation as monotherapy for Parkinson's disease. Proc Natl Acad Sci U S A 2017; 114:3999-4004. [PMID: 28348207 DOI: 10.1073/pnas.1616874114] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the loss of dopaminergic (DAergic) neurons in the substantia nigra and the gradual depletion of dopamine (DA). Current treatments replenish the DA deficit and improve symptoms but induce dyskinesias over time, and neuroprotective therapies are nonexistent. Here we report that Nuclear receptor-related 1 (Nurr1):Retinoid X receptor α (RXRα) activation has a double therapeutic potential for PD, offering both neuroprotective and symptomatic improvement. We designed BRF110, a unique in vivo active Nurr1:RXRα-selective lead molecule, which prevents DAergic neuron demise and striatal DAergic denervation in vivo against PD-causing toxins in a Nurr1-dependent manner. BRF110 also protects against PD-related genetic mutations in patient induced pluripotent stem cell (iPSC)-derived DAergic neurons and a genetic mouse PD model. Remarkably, besides neuroprotection, BRF110 up-regulates tyrosine hydroxylase (TH), aromatic l-amino acid decarboxylase (AADC), and GTP cyclohydrolase I (GCH1) transcription; increases striatal DA in vivo; and has symptomatic efficacy in two postneurodegeneration PD models, without inducing dyskinesias on chronic daily treatment. The combined neuroprotective and symptomatic effects of BRF110 identify Nurr1:RXRα activation as a potential monotherapeutic approach for PD.
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14
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Interaction between gut microbiota and toll-like receptor: from immunity to metabolism. J Mol Med (Berl) 2016; 95:13-20. [PMID: 27639584 PMCID: PMC5225216 DOI: 10.1007/s00109-016-1474-4] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 08/15/2016] [Accepted: 09/08/2016] [Indexed: 02/06/2023]
Abstract
The human gut contains trillions of commensal bacteria, and similar to pathogenic bacteria, the gut microbes and their products can be recognized by toll-like receptors (TLRs). It is well acknowledged that the interaction between gut microbiota and the local TLRs help to maintain the homeostasis of intestinal immunity. High-fat intake or obesity can weaken gut integrity leading to the penetration of gut microbiota or their bacterial products into the circulation, leading to the activation of TLRs on immune cells and subsequently low-grade systemic inflammation in host. Metabolic cells including hepatocytes and adipocytes also express TLRs. Although they are able to produce and secrete inflammatory molecules, the effectiveness remains low compared with the immune cells embedded in the liver and adipose tissue. The interaction of TLRs in these metabolic cells or organs with gut microbiota remains unclear, but a few studies have suggested that the functions of these TLRs are related to metabolism. Alteration of the gut microbiota is associated with body weight change and adiposity in human, and the interaction between the commensal gut microbiota and TLRs may possibly involve both metabolic and immunological regulation. In this review, we will summarize the current findings on the relationship between TLRs and gut microbiota with a focus on metabolic regulation and discuss how such interaction participates in host metabolism.
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15
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Luo Q, Wang Z, Chen H, Fang MH, Xie S, Qian X, Lin X. Identification of Anticancer Drug Candidate Targeting Nuclear Receptor Retinoid X receptor-α from Natural Products using Receptor-Ligand Recognition. ChemistrySelect 2016. [DOI: 10.1002/slct.201600907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Qiang Luo
- Animal Husbandry and Fisheries Research Center; Guangdong Haid Group Co., Ltd.; Guangzhou China
- Institute of Hydrobiology; Chinese Academy of Science; Wuhan China
| | - Zhaokai Wang
- Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Third Institute of Oceanography; State Oceanic Administration; Xiamen China
| | - Huibin Chen
- Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Third Institute of Oceanography; State Oceanic Administration; Xiamen China
| | - Ms. Hui Fang
- Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Third Institute of Oceanography; State Oceanic Administration; Xiamen China
| | - Shouqi Xie
- Institute of Hydrobiology; Chinese Academy of Science; Wuhan China
| | - Xueqiao Qian
- Animal Husbandry and Fisheries Research Center; Guangdong Haid Group Co., Ltd.; Guangzhou China
| | - Xiangzhi Lin
- Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Third Institute of Oceanography; State Oceanic Administration; Xiamen China
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16
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Chances and challenges of retinoid X receptor gamma targeting for regenerative multiple sclerosis treatment. Future Med Chem 2015; 7:2411-3. [DOI: 10.4155/fmc.15.163] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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17
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Steinmetz FP, Mellor CL, Meinl T, Cronin MTD. Screening Chemicals for Receptor-Mediated Toxicological and Pharmacological Endpoints: Using Public Data to Build Screening Tools within a KNIME Workflow. Mol Inform 2015; 34:171-8. [PMID: 27490039 DOI: 10.1002/minf.201400188] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 01/26/2015] [Indexed: 12/13/2022]
Abstract
Assessing compounds for their pharmacological and toxicological properties is of great importance for industry and regulatory agencies. In this study an approach using open source software and open access databases to build screening tools for receptor-mediated effects is presented. The retinoic acid receptor (RAR), as a pharmacologically and toxicologically relevant target, was chosen for this study. RAR agonists are used in the treatment of a number of dermal conditions and specific types of cancer, such as acute promyelocytic leukemia. However, when administered chronically, there is strong evidence that RAR agonists cause hepatosteatosis and liver injury. After compiling information on ligand-protein-interactions, common substructures and physico-chemical properties of ligands were identified manually and coded into SMARTS strings. Based on these SMARTS strings and calculated physico-chemical features, a rule-based screening workflow was built within the KNIME platform. The workflow was evaluated on two datasets: one with RAR agonists exclusively and another large, chemically diverse dataset containing only a few RAR agonists. Possible modifications and applications of screening workflows, dependent on their purpose, are presented.
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Affiliation(s)
- F P Steinmetz
- School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, England phone: +44 151 231 2402
| | - C L Mellor
- School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, England phone: +44 151 231 2402
| | - T Meinl
- KNIME.com AG, Technoparkstr. 1, 8005 Zurich, Switzerland
| | - M T D Cronin
- School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, England phone: +44 151 231 2402.
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18
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Shan PR, Xu WW, Huang ZQ, Pu J, Huang WJ. Protective role of retinoid X receptor in H9c2 cardiomyocytes from hypoxia/reoxygenation injury in rats. World J Emerg Med 2014; 5:122-7. [PMID: 25215161 DOI: 10.5847/wjem.j.issn.1920-8642.2014.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 03/06/2014] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Retinoid X receptor (RXR) plays a central role in the regulation of intracellular receptor signaling pathways. The activation of RXR has protective effect on H2O2-induced apoptosis of H9c2 ventricular cells in rats. But the protective effect and mechanism of activating RXR in cardiomyocytes against hypoxia/reoxygenation (H/R)-induced oxidative iniury are still unclear. METHODS The model of H/R injury was established through hypoxia for 2 hours and reoxygenation for 4 hours in H9c2 cardiomyocytes of rats. 9-cis-retinoic acid (9-cis RA) was obtained as an RXR agonist, and HX531 as an RXR antagonist. Cultured cardiomyocytes were randomly divided into four groups: sham group, H/R group, H/R+9-cis RA -pretreated group (100 nmol/L 9-cis RA), and H/R+9-cis RA+HX531-pretreated group (2.5 μmol/L HX531). The cell viability was measured by MTT, apoptosis rate of cardiomyocytes by flow cytometry analysis, and mitochondrial membrane potential (ΔΨm) by JC-1 fluorescent probe, and protein expressions of Bcl-2, Bax and cleaved caspase-9 with Western blotting. All measurement data were expressed as mean±standard deviation, and analyzed using one-way ANOVA and the Dunnett test. Differences were considered significant when P was <0.05. RESULTS Pretreatment with RXR agonist enhanced cell viability, reduced apoptosis ratio, and stabled ΔΨm. Dot blotting experiments showed that under H/R stress conditions, Bcl-2 protein level decreased, while Bax and cleaved caspase-9 were increased. 9-cis RA administration before H/R stress prevented these effects, but the protective effects of activating RXR on cardiomyocytes against H/R induced oxidative injury were abolished when pretreated with RXR pan-antagonist HX531. CONCLUSION The activation of RXR has protective effects against H/R injury in H9c2 cardiomyocytes of rats through attenuating signaling pathway of mitochondria apoptosis.
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Affiliation(s)
- Pei-Ren Shan
- Department of Cardiology, First AffiliatedHospital of Wenzhou Medical University, Wenzhou 325100, China
| | - Wei-Wei Xu
- Department of Cardiology, First AffiliatedHospital of Wenzhou Medical University, Wenzhou 325100, China
| | - Zhou-Qing Huang
- Department of Cardiology, First AffiliatedHospital of Wenzhou Medical University, Wenzhou 325100, China
| | - Jun Pu
- Department of Cardiology, First AffiliatedHospital of Wenzhou Medical University, Wenzhou 325100, China
| | - Wei-Jian Huang
- Department of Cardiology, First AffiliatedHospital of Wenzhou Medical University, Wenzhou 325100, China
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19
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le Maire A, Bourguet W. Retinoic acid receptors: structural basis for coregulator interaction and exchange. Subcell Biochem 2014; 70:37-54. [PMID: 24962880 DOI: 10.1007/978-94-017-9050-5_3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In the form of heterodimers with retinoid X receptors (RXRs), retinoic acid receptors (RARs) are master regulators of gene expression in humans and important drug targets. They act as ligand-dependent transcription factors that regulate a large variety of gene networks controlling cell growth, differentiation, survival and death. The biological functions of RARs rely on a dynamic series of coregulator exchanges controlled by ligand binding. Unliganded RARs exert a repressor activity by interacting with transcriptional corepressors which themselves serve as docking platforms for the recruitment of histone deacetylases that impose a higher order structure on chromatin which is not permissive to gene transcription. Upon ligand binding, the receptor undergoes conformational changes inducing corepressor release and the recruitment of coactivators with histone acetylase activities allowing chromatin decompaction and gene transcription. In the following, we review the structural determinants of the interaction between RAR and either type of coregulators both at the level of the individual receptor and in the context of the RAR-RXR heterodimers. We also discuss the molecular details of the fine tuning of these associations by the various pharmacological classes of ligands.
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Affiliation(s)
- Albane le Maire
- Inserm U1054, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090, Montpellier, France,
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20
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Álvarez R, Vaz B, Gronemeyer H, de Lera ÁR. Functions, therapeutic applications, and synthesis of retinoids and carotenoids. Chem Rev 2013; 114:1-125. [PMID: 24266866 DOI: 10.1021/cr400126u] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Rosana Álvarez
- Departamento de Química Orgánica, Centro de Investigación Biomédica (CINBIO), and Instituto de Investigación Biomédica de Vigo (IBIV), Universidade de Vigo , 36310 Vigo, Spain
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21
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Sun AQ, Luo Y, Backos DS, Xu S, Balasubramaniyan N, Reigan P, Suchy FJ. Identification of functionally relevant lysine residues that modulate human farnesoid X receptor activation. Mol Pharmacol 2013; 83:1078-86. [PMID: 23462506 PMCID: PMC3920091 DOI: 10.1124/mol.113.084772] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 03/05/2013] [Indexed: 12/20/2022] Open
Abstract
Base amino acid lysine residues play an important role in regulation of nuclear receptors [e.g., farnesyl X receptor (FXR)], leading to enhanced or suppressed biologic activity. To understand the molecular mechanisms and the subsequent effects in modulating FXR functions in diverse biologic processes, we individually replaced eight highly conserved lysine residues of human FXR (hFXR) with arginine. The effects of each mutated FXR on target gene activation, subcellular localization, protein-protein association, and protein-DNA interaction were investigated. Results demonstrated that K122R, K210R, K339R, and K460R mutants of hFXR significantly impaired target gene [organic solute transporter α/β and bile salt export pump (BSEP)] promoter reporter activity in a ligand-dependent fashion. None of the four mutants affected the nuclear localization of FXR. Protein interaction studies show that K210R slightly but significantly decreased FXR/retinoid X receptor (RXR) binding affinity but enhanced the interaction of FXR with lysine methyltransferase Set7/9 by ∼21%. K460R decreased the FXR interaction with Set7/9 by ∼45% but had no significant effects on interaction with RXR. Electrophoretic mobility shift assays demonstrated that hFXR-K210R and -K339R reduced the protein-DNA (IR1 element at hBSEP promoter) binding affinity by ∼80 and ∼90%, respectively. Computational-based protein modeling studies were consistent with these results and provided further insights into the potential underlying mechanisms responsible for these results. In conclusion, four highly conserved lysine residues of hFXR, K122, K210, K339, and K460, have been identified that play a critical role in FXR target gene regulation and molecular interaction (protein-protein and protein-DNA).
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Affiliation(s)
- An-Qiang Sun
- Department of Pediatrics, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA.
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