51
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Gierach I, Li J, Wu WY, Grover GJ, Wood DW. Bacterial biosensors for screening isoform-selective ligands for human thyroid receptors α-1 and β-1. FEBS Open Bio 2012; 2:247-53. [PMID: 23667826 PMCID: PMC3642162 DOI: 10.1016/j.fob.2012.08.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 07/11/2012] [Accepted: 08/08/2012] [Indexed: 12/17/2022] Open
Abstract
Subtype-selective thyromimetics have potential as new pharmaceuticals for the prevention or treatment of heart disease, high LDL cholesterol and obesity, but there are only a few methods that can detect agonistic behavior of TR-active compounds. Among these are the rat pituitary GH3 cell assay and transcriptional activation assays in engineered yeast and mammalian cells. We report the construction and validation of a newly designed TRα-1 bacterial biosensor, which indicates the presence of thyroid active compounds through their impacts on the growth of an engineered Escherichia coli strain in a simple defined medium. This biosensor couples the configuration of a hormone receptor ligand-binding domain to the activity of a thymidylate synthase reporter enzyme through an engineered allosteric fusion protein. The result is a hormone-dependent growth phenotype in the expressing E. coli cells. This sensor can be combined with our previously published TRβ-1 biosensor to detect potentially therapeutic subtype-selective compounds such as GC-1 and KB-141. To demonstrate this capability, we determined the half-maximal effective concentration (EC50) for the compounds T3, Triac, GC-1 and KB-141 using our biosensors, and determined their relative potency in each biosensor strain. Our results are similar to those reported by mammalian cell reporter gene assays, confirming the utility of our assay in identifying TR subtype-selective therapeutics. This biosensor thus provides a high-throughput, receptor-specific, and economical method (less than US$ 0.10 per well at laboratory scale) for identifying important therapeutics against these targets.
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Affiliation(s)
- Izabela Gierach
- Department of Chemical Engineering, Princeton University, Princeton, NJ 08544,USA
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52
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Joharapurkar AA, Dhote VV, Jain MR. Selective Thyromimetics Using Receptor and Tissue Selectivity Approaches: Prospects for Dyslipidemia. J Med Chem 2012; 55:5649-75. [DOI: 10.1021/jm2004706] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Amit A. Joharapurkar
- Department of Pharmacology and Toxicology, Zydus Research Centre, Sarkhej Bavla NH 8A, Moraiya,
Ahmedabad 382210, India
| | - Vipin V. Dhote
- Department of Pharmacology and Toxicology, Zydus Research Centre, Sarkhej Bavla NH 8A, Moraiya,
Ahmedabad 382210, India
| | - Mukul R. Jain
- Department of Pharmacology and Toxicology, Zydus Research Centre, Sarkhej Bavla NH 8A, Moraiya,
Ahmedabad 382210, India
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53
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Hanson RN, McCaskill E, Tongcharoensirikul P, Dilis R, Labaree D, Hochberg RB. Synthesis and evaluation of 17α-(dimethylphenyl)vinyl estradiols as probes of the estrogen receptor-α ligand binding domain. Steroids 2012; 77:471-6. [PMID: 22273809 PMCID: PMC3307546 DOI: 10.1016/j.steroids.2012.01.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 12/22/2011] [Accepted: 01/06/2012] [Indexed: 11/26/2022]
Abstract
As part of our program to explore the influence of small structural modifications on the biological response of the estrogen receptor-α (ERα), we prepared and evaluated a series of mono-and di-substituted phenyl vinyl estradiols. The target compounds were prepared in 45-80% yields using the Stille coupling reaction and evaluated using competitive binding analysis with the ERα-ligand binding domain (hERα-LBD) and estrogenic activity (induction of alkaline phosphatase in Ishikawa cells). Results indicated that the 2,4- and 2,5-dimethyl derivatives, 5b and 5c, had the highest relative binding affinity (RBA=20.5 and 37.3%) and relative stimulatory activity (RSA=101.0% and 12.3%) of the di-methyl series.
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Affiliation(s)
- Robert N Hanson
- Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, United States.
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54
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Brélivet Y, Rochel N, Moras D. Structural analysis of nuclear receptors: from isolated domains to integral proteins. Mol Cell Endocrinol 2012; 348:466-73. [PMID: 21888944 DOI: 10.1016/j.mce.2011.08.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 07/28/2011] [Accepted: 08/12/2011] [Indexed: 11/26/2022]
Abstract
Nuclear receptors (NRs) are ligand dependent transcription factors that regulate gene expression. A number of in depth structure-function relationship studies have been performed, in particular with drug design perspectives. Recent structural results concerning integral receptors in diverse functional states, obtained using a combination of different methods, now allow a better understanding of the mechanisms involved in molecular regulation. The structural data highlight the importance of DNA sequences for binding selectivity and the role of promoter response elements in the spatial organization of the protein domains into functional complexes. The solution structures of several heterodimer complexes reveal how the DNA directs the positioning of coactivators. In the case of PPARγ-RXRα the comparison with the crystal structure reveals two different conformational states that illustrate the flexibility of the receptors. The results shed light on the dynamics of the molecular recognition process.
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Affiliation(s)
- Yann Brélivet
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Institut National de la Santé et de la Recherche Médicale U964/Centre National de Recherche Scientifique UMR7104/Université de Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch, France
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55
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Souza PCT, Barra GB, Velasco LFR, Ribeiro ICJ, Simeoni LA, Togashi M, Webb P, Neves FAR, Skaf MS, Martínez L, Polikarpov I. Helix 12 dynamics and thyroid hormone receptor activity: experimental and molecular dynamics studies of Ile280 mutants. J Mol Biol 2011; 412:882-93. [PMID: 21530542 DOI: 10.1016/j.jmb.2011.04.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 04/06/2011] [Accepted: 04/06/2011] [Indexed: 01/28/2023]
Abstract
Nuclear hormone receptors (NRs) form a family of transcription factors that mediate cellular responses initiated by hormone binding. It is generally recognized that the structure and dynamics of the C-terminal helix 12 (H12) of NRs' ligand binding domain (LBD) are fundamental to the recognition of coactivators and corepressors that modulate receptor function. Here we study the role of three mutations in the I280 residue of H12 of thyroid hormone receptors using site-directed mutagenesis, functional assays, and molecular dynamics simulations. Although residues at position 280 do not interact with coactivators or with the ligand, we show that its mutations can selectively block coactivator and corepressor binding, and affect hormone binding affinity differently. Molecular dynamics simulations suggest that ligand affinity is reduced by indirectly displacing the ligand in the binding pocket, facilitating water penetration and ligand destabilization. Mutations I280R and I280K link H12 to the LBD by forming salt bridges with E457 in H12, stabilizing H12 in a conformation that blocks both corepressor and coactivator recruitment. The I280M mutation, in turn, blocks corepressor binding, but appears to enhance coactivator affinity, suggesting stabilization of H12 in agonist conformation.
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Affiliation(s)
- Paulo C T Souza
- Institute of Chemistry, State University of Campinas, Campinas, SP, Brazil
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56
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Abstract
Selective thyromimetics are synthetic analogs of thyroid hormones with tissue-specific thyroid hormone actions. Tissue selectivity is partly mediated by selectivity for the thyroid hormone receptor-β isoform, but is also enhanced by tissue-selective uptake. Several preclinical animal models and recent human clinical trials have provided sound evidence that thyromimetics can serve as pharmacological tools to improve serum lipids without affecting heart rate. Thyromimetics consistently and efficiently lowered low-density lipoprotein cholesterol and lipoprotein (a) plasma levels without positive chronotropic effects. Most importantly, thyromimetics had a synergistic action when used in addition to 3-hydroxy-3-methylglutaryl CoA reductase inhibitors. Animal data have further suggested that thyromimetics might be useful in the treatment of obesity, hepatic steatosis and atherosclerosis. However, only long-term phase III clinical trials will tell if the observed lipid lowering effects of thyromimetics will improve cardiovascular outcome in humans, too. At the moment, the treatment of dyslipidemia seems to be the major indication for the therapeutic use of thyromimetics, which are now rapidly moving from bench to bed-side.
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Affiliation(s)
- Ivan Tancevski
- Department of Internal Medicine I, Innsbruck Medical University, Innsbruck, Austria.
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57
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Grijota-Martínez C, Samarut E, Scanlan TS, Morte B, Bernal J. In vivo activity of the thyroid hormone receptor beta- and α-selective agonists GC-24 and CO23 on rat liver, heart, and brain. Endocrinology 2011; 152:1136-42. [PMID: 21239431 PMCID: PMC3040061 DOI: 10.1210/en.2010-0813] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Thyroid hormone analogs with selective actions through specific thyroid hormone receptor (TR) subtypes are of great interest. They might offer the possibility of mimicking physiological actions of thyroid hormone with receptor subtype or tissue specificity with therapeutic aims. They are also pharmacological tools to dissect biochemical pathways mediated by specific receptor subtypes, in a complementary way to mouse genetic modifications. In this work, we studied the in vivo activity in developing rats of two thyroid hormone agonists, the TRβ-selective GC-24 and the TRα-selective CO23. Our principal goal was to check whether these compounds were active in the rat brain. Analog activity was assessed by measuring the expression of thyroid hormone target genes in liver, heart, and brain, after administration to hypothyroid rats. GC-24 was very selective for TRβ and lacked activity on the brain. On the other hand, CO23 was active in liver, heart, and brain on genes regulated by either TRα or TRβ. This compound, previously shown to be TRα-selective in tadpoles, displayed no selectivity in the rat in vivo.
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Affiliation(s)
- Carmen Grijota-Martínez
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, 28029 Madrid, Spain
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58
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Affiliation(s)
- Miriam O Ribeiro
- Department of Biological Science, Biological and Health Science Center, MacKenzie Presbiterian University, Sao Paulo SP 01302, Brazil
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59
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Trivella DBB, Sairre MI, Foguel D, Lima LMTR, Polikarpov I. The binding of synthetic triiodo l-thyronine analogs to human transthyretin: molecular basis of cooperative and non-cooperative ligand recognition. J Struct Biol 2010; 173:323-32. [PMID: 20937391 DOI: 10.1016/j.jsb.2010.10.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2010] [Revised: 10/03/2010] [Accepted: 10/05/2010] [Indexed: 11/25/2022]
Abstract
Transthyretin (TTR) is a tetrameric β-sheet-rich transporter protein directly involved in human amyloid diseases. Several classes of small molecules can bind to TTR delaying its amyloid fibril formation, thus being promising drug candidates to treat TTR amyloidoses. In the present study, we characterized the interactions of the synthetic triiodo L-thyronine analogs and thyroid hormone nuclear receptor TRβ-selective agonists GC-1 and GC-24 with the wild type and V30M variant of human transthyretin (TTR). To achieve this aim, we conducted in vitro TTR acid-mediated aggregation and isothermal titration calorimetry experiments and determined the TTR:GC-1 and TTR:GC-24 crystal structures. Our data indicate that both GC-1 and GC-24 bind to TTR in a non-cooperative manner and are good inhibitors of TTR aggregation, with dissociation constants for both hormone binding sites (HBS) in the low micromolar range. Analysis of the crystal structures of TTRwt:GC-1(24) complexes and their comparison with the TTRwt X-ray structure bound to its natural ligand thyroxine (T4) suggests, at the molecular level, the basis for the cooperative process displayed by T4 and the non-cooperative process provoked by both GC-1 and GC-24 during binding to TTR.
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Affiliation(s)
- Daniela B B Trivella
- Instituto de Física de São Carlos-Universidade de São Paulo, São Carlos, SP, Brazil
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60
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de Araujo AS, Martínez L, de Paula Nicoluci R, Skaf MS, Polikarpov I. Structural modeling of high-affinity thyroid receptor-ligand complexes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2010; 39:1523-36. [PMID: 20512645 DOI: 10.1007/s00249-010-0610-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 04/27/2010] [Accepted: 05/04/2010] [Indexed: 11/24/2022]
Abstract
Understanding the molecular basis of the binding modes of natural and synthetic ligands to nuclear receptors is fundamental to our comprehension of the activation mechanism of this important class of hormone regulated transcription factors and to the development of new ligands. Thyroid hormone receptors (TR) are particularly important targets for pharmaceuticals development because TRs are associated with the regulation of metabolic rates, body weight, and circulating levels of cholesterol and triglycerides in humans. While several high-affinity ligands are known, structural information is only partially available. In this work we obtain structural models of several TR-ligand complexes with unknown structure by docking high affinity ligands to the receptors' ligand binding domain with subsequent relaxation by molecular dynamics simulations. The binding modes of these ligands are discussed providing novel insights into the development of TR ligands. The experimental binding free energies are reasonably well-reproduced from the proposed models using a simple linear interaction energy free-energy calculation scheme.
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Affiliation(s)
- Alexandre Suman de Araujo
- Instituto de Física de São Carlos, Universidade de São Paulo, Av Trabalhador SaoCarlense 400, IFSC, Grupo de Cristalografia, PO Box 369, Sao Carlos, SP 13560-970, Brazil
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61
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Huang P, Chandra V, Rastinejad F. Structural overview of the nuclear receptor superfamily: insights into physiology and therapeutics. Annu Rev Physiol 2010; 72:247-72. [PMID: 20148675 DOI: 10.1146/annurev-physiol-021909-135917] [Citation(s) in RCA: 354] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
As ligand-regulated transcription factors, the nuclear hormone receptors are nearly ideal drug targets, with internal pockets that bind to hydrophobic, drug-like molecules and well-characterized ligand-induced conformational changes that recruit transcriptional coregulators to promoter elements. Yet, due to the multitude of genes under the control of a single receptor, the major challenge has been the identification of ligands with gene-selective actions, impacting disease outcomes through a narrow subset of target genes and not across their entire gene-regulatory repertoire. Here, we summarize the concepts and work to date underlying the development of steroidal and nonsteroidal receptor ligands, including the use of crystal structures, high-throughput screens, and rational design approaches for finding useful therapeutic molecules. Difficulties in finding selective receptor modulators require a more complete understanding of receptor interdomain communications, posttranslational modifications, and receptor-protein interactions that could be exploited for target gene selectivity.
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Affiliation(s)
- Pengxiang Huang
- Department of Pharmacology, and Center for Molecular Design, University of Virginia Health System, Charlottesville, VA 22908, USA.
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62
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Hirano T, Kagechika H. Thyromimetics: a review of recent reports and patents (2004 – 2009). Expert Opin Ther Pat 2010; 20:213-28. [DOI: 10.1517/13543770903567069] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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63
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Martínez L, Souza PCT, Garcia W, Batista FAH, Portugal RV, Nascimento AS, Nakahira M, Lima LMTR, Polikarpov I, Skaf MS. On the Denaturation Mechanisms of the Ligand Binding Domain of Thyroid Hormone Receptors. J Phys Chem B 2009; 114:1529-40. [DOI: 10.1021/jp911554p] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Leandro Martínez
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Paulo C. T. Souza
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Wanius Garcia
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Fernanda A. H. Batista
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Rodrigo V. Portugal
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Alessandro S. Nascimento
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Marcel Nakahira
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Luis M. T. R. Lima
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Igor Polikarpov
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Munir S. Skaf
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador SaoCarlense 400-IFSC-Grupo de Crystalografia, P.O. Box 369, Sao Carlos, SP, 13560-970, Brazil, and Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, bloco B, subsolo, sala 34. Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil
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64
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Gaining ligand selectivity in thyroid hormone receptors via entropy. Proc Natl Acad Sci U S A 2009; 106:20717-22. [PMID: 19926848 DOI: 10.1073/pnas.0911024106] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nuclear receptors are important targets for pharmaceuticals, but similarities between family members cause difficulties in obtaining highly selective compounds. Synthetic ligands that are selective for thyroid hormone (TH) receptor beta (TRbeta) vs. TRalpha reduce cholesterol and fat without effects on heart rate; thus, it is important to understand TRbeta-selective binding. Binding of 3 selective ligands (GC-1, KB141, and GC-24) is characterized at the atomic level; preferential binding depends on a nonconserved residue (Asn-331beta) in the TRbeta ligand-binding cavity (LBC), and GC-24 gains extra selectivity from insertion of a bulky side group into an extension of the LBC that only opens up with this ligand. Here we report that the natural TH 3,5,3'-triodothyroacetic acid (Triac) exhibits a previously unrecognized mechanism of TRbeta selectivity. TR x-ray structures reveal better fit of ligand with the TRalpha LBC. The TRbeta LBC, however, expands relative to TRalpha in the presence of Triac (549 A(3) vs. 461 A(3)), and molecular dynamics simulations reveal that water occupies the extra space. Increased solvation compensates for weaker interactions of ligand with TRbeta and permits greater flexibility of the Triac carboxylate group in TRbeta than in TRalpha. We propose that this effect results in lower entropic restraint and decreases free energy of interactions between Triac and TRbeta, explaining subtype-selective binding. Similar effects could potentially be exploited in nuclear receptor drug design.
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65
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Amorim BS, Ueta CB, Freitas BCG, Nassif RJ, Gouveia CHDA, Christoffolete MA, Moriscot AS, Lancelloti CL, Llimona F, Barbeiro HV, de Souza HP, Catanozi S, Passarelli M, Aoki MS, Bianco AC, Ribeiro MO. A TRbeta-selective agonist confers resistance to diet-induced obesity. J Endocrinol 2009; 203:291-9. [PMID: 19713219 PMCID: PMC3133532 DOI: 10.1677/joe-08-0539] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Thyroid hormone receptor beta (TRbeta also listed as THRB on the MGI Database)-selective agonists activate brown adipose tissue (BAT) thermogenesis, while only minimally affecting cardiac activity or lean body mass. Here, we tested the hypothesis that daily administration of the TRbeta agonist GC-24 prevents the metabolic alterations associated with a hypercaloric diet. Rats were placed on a high-fat diet and after a month exhibited increased body weight (BW) and adiposity, fasting hyperglycemia and glucose intolerance, increased plasma levels of triglycerides, cholesterol, nonesterified fatty acids and interleukin-6. While GC-24 administration to these animals did not affect food ingestion or modified the progression of BW gain, it did increase energy expenditure, eliminating the increase in adiposity without causing cardiac hypertrophy. Fasting hyperglycemia remained unchanged, but treatment with GC-24 improved glucose tolerance by increasing insulin sensitivity, and also normalized plasma triglyceride levels. Plasma cholesterol levels were only partially normalized and liver cholesterol content remained high in the GC-24-treated animals. Gene expression in liver, skeletal muscle, and white adipose tissue was only minimally affected by treatment with GC-24, with the main target being BAT. In conclusion, during high-fat feeding treatment with the TRbeta-selective agonist, GC-24 only partially improves metabolic control probably as a result of accelerating the resting metabolic rate.
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Affiliation(s)
- Beatriz S Amorim
- Biological Science Course, CCBS, Presbyterian University Mackenzie, Rua da Consolação, 930 Prédio 38, Curso de Biologia, São Paulo, SP 01302-907, Brazil
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66
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Lima STC, Nguyen NH, Togashi M, Apriletti JW, Nguyen P, Polikarpov I, Scanlan TS, Baxter JD, Webb P. Differential effects of TR ligands on hormone dissociation rates: evidence for multiple ligand entry/exit pathways. J Steroid Biochem Mol Biol 2009; 117:125-31. [PMID: 19729063 PMCID: PMC2784034 DOI: 10.1016/j.jsbmb.2009.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 08/16/2009] [Accepted: 08/21/2009] [Indexed: 11/26/2022]
Abstract
Some nuclear receptor (NR) ligands promote dissociation of radiolabeled bound hormone from the buried ligand binding cavity (LBC) more rapidly than excess unlabeled hormone itself. This result was interpreted to mean that challenger ligands bind allosteric sites on the LBD to induce hormone dissociation, and recent findings indicate that ligands bind weakly to multiple sites on the LBD surface. Here, we show that a large fraction of thyroid hormone receptor (TR) ligands promote rapid dissociation (T(1/2)<2h) of radiolabeled T(3) vs. T(3) (T(1/2) approximately 5-7h). We cannot discern relationships between this effect and ligand size, activity or affinity for TRbeta. One ligand, GC-24, binds the TR LBC and (weakly) to the TRbeta-LBD surface that mediates dimer/heterodimer interaction, but we cannot link this interaction to rapid T(3) dissociation. Instead, several lines of evidence suggest that the challenger ligand must interact with the buried LBC to promote rapid T(3) release. Since previous molecular dynamics simulations suggest that TR ligands leave the LBC by several routes, we propose that a subset of challenger ligands binds and stabilizes a partially unfolded intermediate state of TR that arises during T(3) release and that this effect enhances hormone dissociation.
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Affiliation(s)
- Suzana T. Cunha Lima
- Department of General Biology, Biology Institute. Federal University of Bahia. 147, Barão de Geremoabo Street, - Campus of Ondina, Salvador, BA, 40170–290 Brazil
| | - Ngoc-Ha Nguyen
- Department of Biochemistry and Biophysics, University of California School of Medicine, San Francisco, CA 94143, USA
| | - Marie Togashi
- Health Science Institute. Brasilia University, Asa Norte, Brasilia, DF 70919–970, Brazil
| | - James W. Apriletti
- Diabetes Center, University of California School of Medicine, San Francisco, CA 94143, USA
| | - Phuong Nguyen
- Diabetes Center, University of California School of Medicine, San Francisco, CA 94143, USA
| | - Igor Polikarpov
- Physics Institute of São Carlos, University of São Paulo. 400, Trabalhador São Carlense Av., São Carlos, SP 13560–970, Brazil
| | - Thomas S. Scanlan
- Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR97239
| | - John D. Baxter
- The Methodist Hospital Research Institute. 6565 Fannin St. Houston, TX 77030, USA
| | - Paul Webb
- The Methodist Hospital Research Institute. 6565 Fannin St. Houston, TX 77030, USA
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Valadares NF, Salum LB, Polikarpov I, Andricopulo AD, Garratt RC. Role of Halogen Bonds in Thyroid Hormone Receptor Selectivity: Pharmacophore-Based 3D-QSSR Studies. J Chem Inf Model 2009; 49:2606-16. [DOI: 10.1021/ci900316e] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Napoleão F. Valadares
- Centro de Biotecnologia Molecular Estrutural, Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-Carlense 400, 13560-970 São Carlos-SP, Brazil
| | - Lívia B. Salum
- Centro de Biotecnologia Molecular Estrutural, Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-Carlense 400, 13560-970 São Carlos-SP, Brazil
| | - Igor Polikarpov
- Centro de Biotecnologia Molecular Estrutural, Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-Carlense 400, 13560-970 São Carlos-SP, Brazil
| | - Adriano D. Andricopulo
- Centro de Biotecnologia Molecular Estrutural, Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-Carlense 400, 13560-970 São Carlos-SP, Brazil
| | - Richard C. Garratt
- Centro de Biotecnologia Molecular Estrutural, Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-Carlense 400, 13560-970 São Carlos-SP, Brazil
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68
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Thyroid hormone mimetics: potential applications in atherosclerosis, obesity and type 2 diabetes. Nat Rev Drug Discov 2009; 8:308-20. [PMID: 19337272 DOI: 10.1038/nrd2830] [Citation(s) in RCA: 174] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Thyroid hormones influence heart rate, serum lipids, metabolic rate, body weight and multiple aspects of lipid, carbohydrate, protein and mineral metabolism. Although increased thyroid hormone levels can improve serum lipid profiles and reduce fat, these positive effects are counterbalanced by harmful effects on the heart, muscle and bone. Thus, attempts to use thyroid hormones for cholesterol-lowering and weight loss purposes have so far been limited. However, over the past decade, thyroid hormone analogues that are capable of uncoupling beneficial effects from deleterious effects have been developed. Such drugs could serve as powerful new tools to address two of the largest medical problems in developed countries--atherosclerosis and obesity.
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69
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Jouravel N, Sablin E, Togashi M, Baxter JD, Webb P, Fletterick RJ. Molecular basis for dimer formation of TRbeta variant D355R. Proteins 2009; 75:111-7. [PMID: 18798561 PMCID: PMC2649980 DOI: 10.1002/prot.22225] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Protein quality and stability are critical during protein purification for X-ray crystallography. A target protein that is easy to manipulate and crystallize becomes a valuable product useful for high-throughput crystallography for drug design and discovery. In this work, a single surface mutation, D355R, was shown to be crucial for converting the modestly stable monomeric ligand binding domain of the human thyroid hormone receptor (TR LBD) into a stable dimer. The structure of D335R TR LBD mutant was solved using X-ray crystallography and refined to 2.2 A resolution with R(free)/R values of 24.5/21.7. The crystal asymmetric unit reveals the TR dimer with two molecules of the hormone-bound LBD related by twofold symmetry. The ionic interface between the two LBDs comprises residues within loop H10-H11 and loop H6-H7 as well as the C-terminal halves of helices 8 of both protomers. Direct intermolecular contacts formed between the introduced residue Arg 355 of one TR molecule and Glu 324 of the second molecule become a part of the extended dimerization interface of 1330 A(2) characteristic for a strong complex assembly that is additionally strengthened by buffer solutes.
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Affiliation(s)
- Natalia Jouravel
- Department Biochemistry and Biophysics, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94158, USA. Tel: 415-476-5051; Fax: 415-476-1902; / /
| | - Elena Sablin
- Department Biochemistry and Biophysics, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94158, USA. Tel: 415-476-5051; Fax: 415-476-1902; / /
| | - Marie Togashi
- Diabetes Center & Dept. of Medicine, University California San Francisco (UCSF), 513 Parnassus Avenue, S-1222, Box 0540, Medical Sciences Building, San Francisco, CA 94143, USA. Tel: 415-476-6789; Fax: 415-564-5813; / /
| | - John D. Baxter
- Diabetes Center & Dept. of Medicine, University California San Francisco (UCSF), 513 Parnassus Avenue, S-1222, Box 0540, Medical Sciences Building, San Francisco, CA 94143, USA. Tel: 415-476-6789; Fax: 415-564-5813; / /
| | - Paul Webb
- Diabetes Center & Dept. of Medicine, University California San Francisco (UCSF), 513 Parnassus Avenue, S-1222, Box 0540, Medical Sciences Building, San Francisco, CA 94143, USA. Tel: 415-476-6789; Fax: 415-564-5813; / /
| | - Robert J. Fletterick
- Department Biochemistry and Biophysics, University of California, San Francisco, 600 16th Street, Genentech Hall, San Francisco, CA 94158, USA. Tel: 415-476-5051; Fax: 415-476-1902; / /
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70
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Valadares NF, Polikarpov I, Garratt RC. Ligand induced interaction of thyroid hormone receptor beta with its coregulators. J Steroid Biochem Mol Biol 2008; 112:205-12. [PMID: 19000767 DOI: 10.1016/j.jsbmb.2008.10.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 10/08/2008] [Accepted: 10/09/2008] [Indexed: 12/12/2022]
Abstract
Thyroid hormones exert most of their physiological effects through two thyroid hormone receptor (TR) subtypes, TRalpha and TRbeta, which associate with many transcriptional coregulators to mediate activation or repression of target genes. The search for selective TRbeta ligands has been stimulated by the finding that several pharmacological actions mediated by TRbeta might be beneficial in medical conditions such as obesity, hypercholesterolemia and diabetes. Here, we present a new methodology which employs surface plasmon resonance to investigate the interactions between TRbeta ligand binding domain (LBD) complexes and peptides derived from the nuclear receptor interaction motifs of two of its coregulators, SRC2 and DAX1. The effect of several TRbeta ligands, including the TRbeta selective agonist GC-1 and the TRbeta selective antagonist NH-3, were investigated. We also determined the kinetic rate constants for the interaction of TRbeta-T3 with both coregulators, and accessed the thermodynamic parameters for the interaction with DAX1. Our findings suggest that flexibility plays an important role in the interaction between the receptor and its coregulators, and point out important aspects of experimental design that should be addressed when using TRbeta LBD and its agonists. Furthermore, the methodology described here may be useful for the identification of new TRbeta ligands.
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Affiliation(s)
- Napoleão F Valadares
- Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense 400, 13560-970 São Carlos, SP, Brazil.
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71
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Denver RJ, Hu F, Scanlan TS, Furlow JD. Thyroid hormone receptor subtype specificity for hormone-dependent neurogenesis in Xenopus laevis. Dev Biol 2008; 326:155-68. [PMID: 19056375 DOI: 10.1016/j.ydbio.2008.11.005] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 10/31/2008] [Accepted: 11/04/2008] [Indexed: 11/30/2022]
Abstract
Thyroid hormone (T(3)) influences cell proliferation, death and differentiation during development of the central nervous system (CNS). Hormone action is mediated by T(3) receptors (TR) of which there are two subtypes, TRalpha and TRbeta. Specific roles for TR subtypes in CNS development are poorly understood. We analyzed involvement of TRalpha and TRbeta in neural cell proliferation during metamorphosis of Xenopus laevis. Cell proliferation in the ventricular/subventricular neurogenic zones of the tadpole brain increased dramatically during metamorphosis. This increase was dependent on T(3) until mid-prometamorphosis, after which cell proliferation decreased and became refractory to T(3). Using double labeling fluorescent histochemistry with confocal microscopy we found TRalpha expressed throughout the tadpole brain, with strongest expression in proliferating cells. By contrast, TRbeta was expressed predominantly outside of neurogenic zones. To corroborate the histochemical results we transfected living tadpole brain with a Xenopus TRbeta promoter-EGFP plasmid and found that most EGFP expressing cells were not dividing. Lastly, treatment with the TRalpha selective agonist CO23 increased brain cell proliferation; whereas, treatment with the TRbeta-selective agonists GC1 or GC24 did not. Our findings support the view that T(3) acts to induce cell proliferation in the tadpole brain predominantly, if not exclusively, via TRalpha.
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Affiliation(s)
- Robert J Denver
- Department of Molecular, Cellular and Developmental Biology, The University of Michigan, Ann Arbor, USA
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72
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Scanlan TS. Sobetirome: a case history of bench-to-clinic drug discovery and development. Heart Fail Rev 2008; 15:177-82. [DOI: 10.1007/s10741-008-9122-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 10/21/2008] [Indexed: 10/21/2022]
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73
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Kruse SW, Suino-Powell K, Zhou XE, Kretschman JE, Reynolds R, Vonrhein C, Xu Y, Wang L, Tsai SY, Tsai MJ, Xu HE. Identification of COUP-TFII orphan nuclear receptor as a retinoic acid-activated receptor. PLoS Biol 2008; 6:e227. [PMID: 18798693 PMCID: PMC2535662 DOI: 10.1371/journal.pbio.0060227] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Accepted: 08/04/2008] [Indexed: 12/22/2022] Open
Abstract
The chicken ovalbumin upstream promoter-transcription factors (COUP-TFI and II) make up the most conserved subfamily of nuclear receptors that play key roles in angiogenesis, neuronal development, organogenesis, cell fate determination, and metabolic homeostasis. Although the biological functions of COUP-TFs have been studied extensively, little is known of their structural features or aspects of ligand regulation. Here we report the ligand-free 1.48 Å crystal structure of the human COUP-TFII ligand-binding domain. The structure reveals an autorepressed conformation of the receptor, where helix α10 is bent into the ligand-binding pocket and the activation function-2 helix is folded into the cofactor binding site, thus preventing the recruitment of coactivators. In contrast, in multiple cell lines, COUP-TFII exhibits constitutive transcriptional activity, which can be further potentiated by nuclear receptor coactivators. Mutations designed to disrupt cofactor binding, dimerization, and ligand binding, substantially reduce the COUP-TFII transcriptional activity. Importantly, retinoid acids are able to promote COUP-TFII to recruit coactivators and activate a COUP-TF reporter construct. Although the concentration needed is higher than the physiological levels of retinoic acids, these findings demonstrate that COUP-TFII is a ligand-regulated nuclear receptor, in which ligands activate the receptor by releasing it from the autorepressed conformation. Unlike other classes of receptors, nuclear receptors can bind directly to DNA and act as transcription factors, playing key roles in embryonic development and cellular metabolism. Most nuclear receptors are activated by signal-triggering molecules (ligands) and can regulate their activity by recruiting coactivator proteins. However, the ligands are unknown for a subset of “orphan” nuclear receptors, including the chicken ovalbumin promoter-transcription factors (COUP-TFI and II, and EAR2). COUP-TFs are the most conserved nuclear receptors, with roles in angiogenesis, neuronal development, organogenesis, and metabolic homeostasis. Here we demonstrate that COUP-TFII is a ligand-regulated nuclear receptor that can be activated by unphysiological micromolar concentrations of retinoic acids. We determined the structure of the ligand-free ligand-binding domain of the human COUP-TFII, revealing the autorepressed conformation of the receptor, where helix α10 is bent into the ligand-binding pocket and the activation function-2 helix is folded into the cofactor binding site, thus preventing the recruitment of coactivators. These results suggest a mechanism where ligands activate COUP-TFII by releasing the receptor from the autorepressed conformation. The identification of COUP-TFII as a low-affinity retinoic acid receptor suggests ways of searching for the endogenous ligands that may ultimately link retinoic acid and COUP-TF signaling pathways. Structural and functional studies reveal that the orphan nuclear receptor COUP-TFII is a low-affinity receptor for retinoic acids. paving the way to finding the endogenous ligands that may ultimately link retinoic acid and COUP-TF signaling pathways.
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Affiliation(s)
- Schoen W Kruse
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | - Kelly Suino-Powell
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | - X. Edward Zhou
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | - Jennifer E Kretschman
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | - Ross Reynolds
- Department of Physics, Grand Valley State University, Allendale, Michigan, United States of America
| | - Clemens Vonrhein
- Global Phasing Ltd., Sheraton House, Castle Park, Cambridge, United Kingdom
| | - Yong Xu
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | - Liliang Wang
- Department of Molecular and Cellular Biology and Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Sophia Y Tsai
- Department of Molecular and Cellular Biology and Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ming-Jer Tsai
- Department of Molecular and Cellular Biology and Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - H. Eric Xu
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
- * To whom correspondence should be addressed. E-mail:
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74
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Martínez L, Polikarpov I, Skaf MS. Only subtle protein conformational adaptations are required for ligand binding to thyroid hormone receptors: simulations using a novel multipoint steered molecular dynamics approach. J Phys Chem B 2008; 112:10741-51. [PMID: 18681473 DOI: 10.1021/jp803403c] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Thyroid hormone receptors (TR) are hormone-dependent transcription regulators that play a major role in human health, development, and metabolic functions. The thyroid hormone resistance syndrome, diabetes, obesity, and some types of cancer are just a few examples of important diseases that are related to TR malfunctioning, particularly impaired hormone binding. Ligand binding to and dissociation from the receptor ultimately control gene transcription and, thus, detailed knowledge of binding and release mechanisms are fundamental for the comprehension of the receptor's biological function and development of pharmaceuticals. In this work, we present the first computational study of ligand entry into the ligand binding domain (LBD) of a nuclear receptor. We report molecular dynamics simulations of ligand binding to TRs using a generalization of the steered molecular dynamics technique designed to perform single-molecule pulling simulations along arbitrarily nonlinear driving pathways. We show that only gentle protein movements and conformational adaptations are required for ligand entry into the LBDs and that the magnitude of the forces applied to assist ligand binding are of the order of the forces involved in ligand dissociation. Our simulations suggest an alternative view for the mechanisms ligand binding and dissociation of ligands from nuclear receptors in which ligands can simply diffuse through the protein surface to reach proper positioning within the binding pocket. The proposed picture indicates that the large-amplitude protein motions suggested by the apo- and holo-RXRalpha crystallographic structures are not required, reconciling conformational changes of LBDs required for ligand entry with other nuclear receptors apo-structures that resemble the ligand-bound LBDs.
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Affiliation(s)
- Leandro Martínez
- Institute of Chemistry, State University of Campinas-UNICAMP, P.O. Box 6154, Campinas, SP, 13084-862, Brazil
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75
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Raval S, Raval P, Bandyopadhyay D, Soni K, Yevale D, Jogiya D, Modi H, Joharapurkar A, Gandhi N, Jain MR, Patel PR. Design and synthesis of novel 3-hydroxy-cyclobut-3-ene-1,2-dione derivatives as thyroid hormone receptor β (TR-β) selective ligands. Bioorg Med Chem Lett 2008; 18:3919-24. [DOI: 10.1016/j.bmcl.2008.06.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2007] [Revised: 05/19/2008] [Accepted: 06/11/2008] [Indexed: 12/17/2022]
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76
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Zheng J, Hashimoto A, Putnam M, Miller K, Koh JT. Development of a thyroid hormone receptor targeting conjugate. Bioconjug Chem 2008; 19:1227-34. [PMID: 18507428 DOI: 10.1021/bc8000326] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Molecular conjugates of hormone receptor-ligands with molecular probes or functional domains are finding diverse applications in chemical biology. Whereas many examples of hormone conjugates that target steroid hormone receptors have been reported, practical ligand conjugates that target the nuclear thyroid hormone receptor (TRbeta) are lacking. TR-targeting conjugate scaffolds based on the ligands GC-1 and NH-2 and the natural ligand triiodothyronine (T3) were synthesized and evaluated in vitro and in cellular assays. Whereas the T3 or GC-1 based conjugates did not bind TRbeta with high affinity, the NH-2 inspired fluorescein-conjugate JZ01 showed low nanomolar affinity for TRbeta and could be used as a nonradiometric probe for ligand binding. A related analogue JZ07 was a potent TR antagonist that is 13-fold selective for TRbeta over TRalpha. JZ01 localizes in the nuclei of TRbeta expressing cells and may serve as a prototype for other TR-targeting conjugates.
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Affiliation(s)
- Jianfei Zheng
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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77
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Du J, Qin J, Liu H, Yao X. 3D-QSAR and molecular docking studies of selective agonists for the thyroid hormone receptor beta. J Mol Graph Model 2008; 27:95-104. [PMID: 18436460 DOI: 10.1016/j.jmgm.2008.03.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2007] [Revised: 03/10/2008] [Accepted: 03/10/2008] [Indexed: 11/15/2022]
Abstract
Three-dimensional quantitative structure-activity relationship (3D-QSAR) models were developed using comparative molecular field analysis (CoMFA) and comparative molecular similarity analysis (CoMSIA) on a series of agonists of thyroid hormone receptor beta (TRbeta), which may lead to safe therapies for non-thyroid disorders while avoiding the cardiac side effects. The reasonable q(2) (cross-validated) values 0.600 and 0.616 and non-cross-validated r(2) values of 0.974 and 0.974 were obtained for CoMFA and CoMSIA models for the training set compounds, respectively. The predictive ability of two models was validated using a test set of 12 molecules which gave predictive correlation coefficients (r(pred)(2)) of 0.688 and 0.674, respectively. The Lamarckian Genetic Algorithm (LGA) of AutoDock 4.0 was employed to explore the binding mode of the compound at the active site of TRbeta. The results not only lead to a better understanding of interactions between these agonists and the thyroid hormone receptor beta but also can provide us some useful information about the influence of structures on the activity which will be very useful for designing some new agonist with desired activity.
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Affiliation(s)
- Juan Du
- Department of Chemistry, Lanzhou University, Lanzhou 730000, China
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78
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Suino-Powell K, Xu Y, Zhang C, Tao YG, Tolbert WD, Simons SS, Xu HE. Doubling the size of the glucocorticoid receptor ligand binding pocket by deacylcortivazol. Mol Cell Biol 2008; 28:1915-23. [PMID: 18160712 PMCID: PMC2268401 DOI: 10.1128/mcb.01541-07] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 10/10/2007] [Accepted: 12/17/2007] [Indexed: 01/14/2023] Open
Abstract
A common feature of nuclear receptor ligand binding domains (LBD) is a helical sandwich fold that nests a ligand binding pocket within the bottom half of the domain. Here we report that the ligand pocket of glucocorticoid receptor (GR) can be continuously extended into the top half of the LBD by binding to deacylcortivazol (DAC), an extremely potent glucocorticoid. It has been puzzling for decades why DAC, which contains a phenylpyrazole replacement at the conserved 3-ketone of steroid hormones that are normally required for activation of their cognate receptors, is a potent GR activator. The crystal structure of the GR LBD bound to DAC and the fourth LXXLL motif of steroid receptor coactivator 1 reveals that the GR ligand binding pocket is expanded to a size of 1,070 A(3), effectively doubling the size of the GR dexamethasone-binding pocket of 540 A(3) and yet leaving the structure of the coactivator binding site intact. DAC occupies only approximately 50% of the space of the pocket but makes intricate interactions with the receptor around the phenylpyrazole group that accounts for the high-affinity binding of DAC. The dramatic expansion of the DAC-binding pocket thus highlights the conformational adaptability of GR to ligand binding. The new structure also allows docking of various nonsteroidal ligands that cannot be fitted into the previous structures, thus providing a new rational template for drug discovery of steroidal and nonsteroidal glucocorticoids that can be specifically designed to reach the unoccupied space of the expanded pocket.
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Affiliation(s)
- Kelly Suino-Powell
- Laboratory of Structural Sciences, Van Andel Research Institute, 333 Bostwick Avenue, Grand Rapids, MI 49503, USA
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79
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Abstract
Thyroid hormone affects in a myriad of biological processes such as development, growth, and metabolic control. Triiodothyronine (T3) is the biologically active form of thyroid hormone that acts through nuclear receptors, TRalpha and TRbeta, regulating gene expression. Given that the distribution of these receptors is heterogeneous amongst the different tissues, it is not surprising that some physiological effects of T3 are isoform specific. For example, while TRalpha is the dominant receptor in the brain and skeletal system and mediates most of the synergism between T3 and the sympathetic signaling pathway in the heart, TRbeta is abundant in liver and is probably the isoform that mediates most of the T3 effects on lipid metabolism. Thus, it makes sense to develop compounds that selectively act on either one of the TRs, allowing for the activation of specific T3-dependent pathways. This article reviews the recent progress made in this area, focusing on the physiological effects of compounds that lower serum cholesterol and decrease fat mass, as they spare skeletal muscle and bone masses, as well as the heart. The available studies indicate that achieving selective activation of different TR-mediated pathways is a promising strategy for treating lipid disorders and obesity.
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Affiliation(s)
- Miriam O Ribeiro
- Ciências Biológicas (CCBS), Universidade Presbiteriana Mackenzie, São Paulo, Brazil.
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80
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Bleicher L, Aparicio R, Nunes FM, Martinez L, Gomes Dias SM, Figueira ACM, Santos MAM, Venturelli WH, da Silva R, Donate PM, Neves FA, Simeoni LA, Baxter JD, Webb P, Skaf MS, Polikarpov I. Structural basis of GC-1 selectivity for thyroid hormone receptor isoforms. BMC STRUCTURAL BIOLOGY 2008; 8:8. [PMID: 18237438 PMCID: PMC2275733 DOI: 10.1186/1472-6807-8-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2007] [Accepted: 01/31/2008] [Indexed: 12/14/2022]
Abstract
Background Thyroid receptors, TRα and TRβ, are involved in important physiological functions such as metabolism, cholesterol level and heart activities. Whereas metabolism increase and cholesterol level lowering could be achieved by TRβ isoform activation, TRα activation affects heart rates. Therefore, β-selective thyromimetics have been developed as promising drug-candidates for treatment of obesity and elevated cholesterol level. GC-1 [3,5-dimethyl-4-(4'-hydroxy-3'-isopropylbenzyl)-phenoxy acetic acid] has ability to lower LDL cholesterol with 600- to 1400-fold more potency and approximately two- to threefold more efficacy than atorvastatin (Lipitor©) in studies in rats, mice and monkeys. Results To investigate GC-1 specificity, we solved crystal structures and performed molecular dynamics simulations of both isoforms complexed with GC-1. Crystal structures reveal that, in TRα Arg228 is observed in multiple conformations, an effect triggered by the differences in the interactions between GC-1 and Ser277 or the corresponding asparagine (Asn331) of TRβ. The corresponding Arg282 of TRβ is observed in only one single stable conformation, interacting effectively with the ligand. Molecular dynamics support this model: our simulations show that the multiple conformations can be observed for the Arg228 in TRα, in which the ligand interacts either strongly with the ligand or with the Ser277 residue. In contrast, a single stable Arg282 conformation is observed for TRβ, in which it strongly interacts with both GC-1 and the Asn331. Conclusion Our analysis suggests that the key factors for GC-1 selectivity are the presence of an oxyacetic acid ester oxygen and the absence of the amino group relative to T3. These results shed light into the β-selectivity of GC-1 and may assist the development of new compounds with potential as drug candidates to the treatment of hypercholesterolemia and obesity.
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Affiliation(s)
- Lucas Bleicher
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São Carlense, 400 CEP 13560-970 São Carlos, SP, Brazil.
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81
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Grover GJ, Kelly J, Malm J. Thyroid hormone receptor subtype-β-selective agonists as potential treatments for metabolic syndrome. ACTA ACUST UNITED AC 2007. [DOI: 10.2217/17460875.2.6.641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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82
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Estébanez-Perpiñá E, Arnold AA, Nguyen P, Rodrigues ED, Mar E, Bateman R, Pallai P, Shokat KM, Baxter JD, Guy RK, Webb P, Fletterick RJ. A surface on the androgen receptor that allosterically regulates coactivator binding. Proc Natl Acad Sci U S A 2007; 104:16074-9. [PMID: 17911242 PMCID: PMC1999396 DOI: 10.1073/pnas.0708036104] [Citation(s) in RCA: 230] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Current approaches to inhibit nuclear receptor (NR) activity target the hormone binding pocket but face limitations. We have proposed that inhibitors, which bind to nuclear receptor surfaces that mediate assembly of the receptor's binding partners, might overcome some of these limitations. The androgen receptor (AR) plays a central role in prostate cancer, but conventional inhibitors lose effectiveness as cancer treatments because anti-androgen resistance usually develops. We conducted functional and x-ray screens to identify compounds that bind the AR surface and block binding of coactivators for AR activation function 2 (AF-2). Four compounds that block coactivator binding in solution with IC(50) approximately 50 microM and inhibit AF-2 activity in cells were detected: three nonsteroidal antiinflammatory drugs and the thyroid hormone 3,3',5-triiodothyroacetic acid. Although visualization of compounds at the AR surface reveals weak binding at AF-2, the most potent inhibitors bind preferentially to a previously unknown regulatory surface cleft termed binding function (BF)-3, which is a known target for mutations in prostate cancer and androgen insensitivity syndrome. X-ray structural analysis reveals that 3,3',5-triiodothyroacetic acid binding to BF-3 remodels the adjacent interaction site AF-2 to weaken coactivator binding. Mutation of residues that form BF-3 inhibits AR function and AR AF-2 activity. We propose that BF-3 is a previously unrecognized allosteric regulatory site needed for AR activity in vivo and a possible pharmaceutical target.
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Affiliation(s)
| | - Alexander A. Arnold
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105; and
| | - Phuong Nguyen
- Diabetes Center and Department of Medicine, University of California, San Francisco, CA 94143
| | - Edson Delgado Rodrigues
- Diabetes Center and Department of Medicine, University of California, San Francisco, CA 94143
| | - Ellena Mar
- *Department of Biochemistry and Biophysics
| | | | | | | | - John D. Baxter
- Diabetes Center and Department of Medicine, University of California, San Francisco, CA 94143
- To whom correspondence may be addressed. E-mail: or
| | - R. Kiplin Guy
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105; and
| | - Paul Webb
- Diabetes Center and Department of Medicine, University of California, San Francisco, CA 94143
| | - Robert J. Fletterick
- *Department of Biochemistry and Biophysics
- To whom correspondence may be addressed. E-mail: or
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83
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EstÉbanez-PerpiñÁ E, Jouravel N, Fletterick RJ. Perspectives on designs of antiandrogens for prostate cancer. Expert Opin Drug Discov 2007; 2:1341-55. [DOI: 10.1517/17460441.2.10.1341] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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84
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Valadares NF, Castilho MS, Polikarpov I, Garratt RC. 2D QSAR studies on thyroid hormone receptor ligands. Bioorg Med Chem 2007; 15:4609-17. [PMID: 17467994 DOI: 10.1016/j.bmc.2007.04.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2007] [Revised: 03/27/2007] [Accepted: 04/04/2007] [Indexed: 12/25/2022]
Abstract
2D QSAR studies were carried out for a series of 55 ligands for the Thyroid receptors, TRalpha and TRbeta. Significant cross-validated correlation coefficients (q(2)=0.781 (TRalpha) and 0.693 (TRbeta)) were obtained. The models' predictive abilities were proved more valuable than the classical 2D-QSAR, and were further investigated by means of an external test set of 13 compounds. The predicted values are in good agreement with experimental values, suggesting that the models could be useful in the design of novel, more potent TR ligands. Contribution map analysis identified a number of positions that are promising for the development of receptor isoform specific ligands.
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Affiliation(s)
- Napoleão F Valadares
- Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-carlense 400, 13560-970 São Carlos-SP, Brazil.
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85
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Ciesielski F, Rochel N, Moras D. Adaptability of the Vitamin D nuclear receptor to the synthetic ligand Gemini: remodelling the LBP with one side chain rotation. J Steroid Biochem Mol Biol 2007; 103:235-42. [PMID: 17218092 DOI: 10.1016/j.jsbmb.2006.12.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The crystal structure of the ligand binding domain (LBD) of the wild-type Vitamin D receptor (VDR) of zebrafish bound to Gemini, a synthetic agonist ligand with two identical side chains branching at carbon 20 reveals a ligand-dependent structural rearrangement of the ligand binding pocket (LBP). The rotation of a Leu side chain opens the access to a channel that can accommodate the second side chain of the ligand. The 25% increase of the LBP's volume does not alter the essential agonist features of VDR. The possibility to adapt the LBP to novel ligands with different chemistry and/or structure opens new perspectives in the design of more specifically targeted ligands.
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Affiliation(s)
- Fabrice Ciesielski
- Département de Biologie et de Génomique Structurales, IGBMC, CNRS/INSERM Université Louis Pasteur, Parc d'innovation BP10142, 67404 Illkirch Cedex, France
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86
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Flamant F, Baxter JD, Forrest D, Refetoff S, Samuels H, Scanlan TS, Vennström B, Samarut J. International Union of Pharmacology. LIX. The pharmacology and classification of the nuclear receptor superfamily: thyroid hormone receptors. Pharmacol Rev 2007; 58:705-11. [PMID: 17132849 DOI: 10.1124/pr.58.4.3] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Frédéric Flamant
- Unité Mixte de Recherche, Centre National de la Recherche Scientifique 5665, Laboratoire Associé Institut National de la Recherche Agronomique 913, l'Institut Fédératif de Recherches 128, Lyon, France.
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87
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Bohl CE, Wu Z, Miller DD, Bell CE, Dalton JT. Crystal structure of the T877A human androgen receptor ligand-binding domain complexed to cyproterone acetate provides insight for ligand-induced conformational changes and structure-based drug design. J Biol Chem 2007; 282:13648-55. [PMID: 17311914 PMCID: PMC2080778 DOI: 10.1074/jbc.m611711200] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyproterone acetate (CPA) is a steroidal antiandrogen used clinically in the treatment of prostate cancer. Compared with steroidal agonists for the androgen receptor (AR) (e.g. dihydrotestosterone, R1881), CPA is bulkier in structure and therefore seemingly incompatible with the binding pockets observed in currently available x-ray crystal structures of the AR ligand-binding domain (LBD). We solved the x-ray crystal structure of the human AR LBD bound to CPA at 1.8A in the T877A variant, a mutation known to increase the agonist activity of CPA and therefore facilitate purification and crystal formation of the receptor.drug complex. The structure demonstrates that bulk from the 17alpha-acetate group of CPA induces movement of the Leu-701 side chain, which results in partial unfolding of the C-terminal end of helix 11 and displacement of the loop between helices 11 and 12 in comparison to all other AR LBD crystal structures published to date. This structural alteration leads to an expansion of the AR binding cavity to include an additional pocket bordered by Leu-701, Leu-704, Ser-778, Met-780, Phe-876, and Leu-880. Further, we found that CPA invokes transcriptional activation in the L701A AR at low nanomolar concentrations similar to the T877A mutant. Analogous mutations in the glucocorticoid receptor (GR) and progesterone receptor were constructed, and we found that CPA was also converted into a potent agonist in the M560A GR. Altogether, these data offer information for structure-based drug design, elucidate flexible regions of the AR LBD, and provide insight as to how CPA antagonizes the AR and GR.
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MESH Headings
- Amino Acid Substitution
- Amino Acids
- Crystallography, X-Ray
- Cyproterone Acetate/chemistry
- Cyproterone Acetate/metabolism
- Drug Design
- Humans
- Ligands
- Mutation, Missense
- Protein Binding/genetics
- Protein Structure, Secondary
- Protein Structure, Tertiary/genetics
- Receptors, Androgen/chemistry
- Receptors, Androgen/genetics
- Receptors, Androgen/metabolism
- Receptors, Glucocorticoid
- Receptors, Progesterone
- Structural Homology, Protein
- Structure-Activity Relationship
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Affiliation(s)
- Casey E Bohl
- Division of Pharmaceutics, College of Pharmacy, Ohio State University, Columbus, Ohio 43210, USA
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88
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Velasco LFR, Togashi M, Walfish PG, Pessanha RP, Moura FN, Barra GB, Nguyen P, Rebong R, Yuan C, Simeoni LA, Ribeiro RCJ, Baxter JD, Webb P, Neves FAR. Thyroid hormone response element organization dictates the composition of active receptor. J Biol Chem 2007; 282:12458-66. [PMID: 17311926 DOI: 10.1074/jbc.m610700200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thyroid hormone (triiodothyronine, T(3)) is known to activate transcription by binding heterodimers of thyroid hormone receptors (TRs) and retinoid X receptors (RXRs). RXR-TRs bind to T(3) response elements (TREs) composed of direct repeats of the sequence AGGTCA spaced by four nucleotides (DR-4). In other TREs, however, the half-sites can be arranged as inverted palindromes and palindromes (Pal). Here we show that TR homodimers and monomers activate transcription from representative TREs with alternate half-site placements. TR beta activates transcription more efficiently than TR alpha at an inverted palindrome (F2), and this correlates with preferential TR beta homodimer formation at F2 in vitro. Furthermore, reconstruction of TR transcription complexes in yeast indicates that TR beta homodimers are active at F2, whereas RXR-TRs are active at DR-4 and Pal. Finally, analysis of TR beta mutations that block homodimer and/or heterodimer formation reveal TRE-selective requirements for these surfaces in mammalian cells, which suggest that TR beta homodimers are active at F2, RXR-TRs at DR-4, and TR monomers at Pal. TR beta requires higher levels of hormone for activation at F2 than other TREs, and this differential effect is abolished by a dimer surface mutation suggesting that it is related to composition of the TR.TRE complex. We propose that interactions of particular TR oligomers with different elements play unappreciated roles in TRE-selective actions of liganded TRs in vivo.
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Affiliation(s)
- Lara F R Velasco
- Molecular Pharmacology Laboratory, Department of Pharmaceutical Sciences, School of Health Sciences, University of Brasilia, Brasília, DF, Brazil
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89
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Chapo J, Peng Y, Pitts KR. A phosphorimager-based filter binding thyroid hormone receptor competition assay for chemical screening. J Pharmacol Toxicol Methods 2006; 56:28-33. [PMID: 17276701 DOI: 10.1016/j.vascn.2006.12.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2006] [Accepted: 12/11/2006] [Indexed: 10/23/2022]
Abstract
INTRODUCTION A phosphorimager-based filter binding thyroid hormone receptor (THR) competition assay has been developed for use in verifying hits from compound library screens. METHODS This method employs in vitro translated ligand binding domains (LBDs) of THRalpha and THRbeta, separation through nitrocellulose via a 96-well vacuum manifold, and analysis of receptor-bound radioactivity by phosphorimaging. RESULTS A standard curve of [I(125)]T3 showed a linear response over the dynamic range of a competition assay, and a comparison of Sephadex G-25 column separation and gamma counting with en masse filtration and phosphorimaging revealed similar IC(50) and K(i) values when using unlabeled T3 as competitor. In addition, this method produced IC(50) and K(i) values for the known T3 competitors [3,5-Dimethyl-4-(4'-hydoxy-3'-isopropylbenzyl) phenoxy] acetic acid (GC-1) and 3,5-diiodothyropropionic acid (DITPA) similar to those reported elsewhere. DISCUSSION These data suggest that filtration and phosphorimaging adequately and properly reproduces binding values associated with THR competition. Further, this method gave a 3-fold reduction in time and a 40-fold reduction in radioactive waste over the column-based method. These reductions allow for a substantial increase in assay throughput. Taken together, these data suggest that en masse filtration and phosphorimaging is an efficient and tractable method for verifying large groups of putative T3 competitors in vitro.
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Affiliation(s)
- Joseph Chapo
- Molecular Pharmacology, Myogen, Inc., Westminster, CO 80021, USA
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90
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Abstract
Small molecules that function as highly selective agonists and antagonists of cellular receptors comprise some of the most valuable therapeutic agents and molecular probes. A recent paper describes the design, synthesis, and evaluation of CO23, the first potent and specific agonist of thyroid hormone receptor-alpha (TRalpha), a member of the nuclear receptor (NR) superfamily of transcription factors. Together with previously reported TRbeta-selective agonists such as GC-1, these compounds represent powerful new tools for studying gene expression, signaling, differentiation, and development controlled by this important NR.
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Affiliation(s)
- Blake R Peterson
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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91
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Ocasio CA, Scanlan TS. Design and characterization of a thyroid hormone receptor alpha (TRalpha)-specific agonist. ACS Chem Biol 2006; 1:585-93. [PMID: 17168554 DOI: 10.1021/cb600311v] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Thyroid hormone is a classical endocrine signaling molecule that regulates a diverse array of physiological processes ranging from energy metabolism to cardiac performance. The active form of thyroid hormone, 3,5,3'-triiodo- l -thyronine or T 3 , exerts many of its actions through its receptor, the thyroid hormone receptor (TR), of which there are two subtypes for two isoforms: TRalpha 1 , TRalpha 2 , TRbeta 1 , and TRbeta 2 . Although TR isoforms, with the exception of TRbeta 2 , are expressed in all tissues, they display different patterns of expression in different tissues, giving rise to tissue-specific isoform actions. Currently, several TRbeta-selective agonists have been developed; however, TRalpha-selective agonists have remained elusive. Herein, we report the synthesis and biological evaluation of CO23, the first potent thyromimetic with TRalpha-specific effects in vitro and in vivo .
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Affiliation(s)
- Cory A Ocasio
- Chemistry and Chemical Biology Graduate Program and the Department of Pharmaceutical Chemistry, University of California-San Francisco, 600 16th Street, San Francisco, California 94143-2280, USA
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92
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Koehler K, Gordon S, Brandt P, Carlsson B, Bäcksbro-Saeidi A, Apelqvist T, Agback P, Grover GJ, Nelson W, Grynfarb M, Färnegårdh M, Rehnmark S, Malm J. Thyroid Receptor Ligands. 6. A High Affinity “Direct Antagonist” Selective for the Thyroid Hormone Receptor. J Med Chem 2006; 49:6635-7. [PMID: 17154490 DOI: 10.1021/jm060521i] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new high-affinity thyroid hormone antagonist 6 with druglike properties was designed and synthesized. The compound behaved as an antagonist in a cell transactivation assay, and in a first in vivo experiment in rats.
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93
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Nascimento AS, Dias SMG, Nunes FM, Aparício R, Ambrosio ALB, Bleicher L, Figueira ACM, Santos MAM, de Oliveira Neto M, Fischer H, Togashi M, Craievich AF, Garratt RC, Baxter JD, Webb P, Polikarpov I. Structural Rearrangements in the Thyroid Hormone Receptor Hinge Domain and Their Putative Role in the Receptor Function. J Mol Biol 2006; 360:586-98. [PMID: 16781732 DOI: 10.1016/j.jmb.2006.05.008] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 04/12/2006] [Accepted: 05/03/2006] [Indexed: 11/21/2022]
Abstract
The thyroid hormone receptor (TR) D-domain links the ligand-binding domain (LBD, EF-domain) to the DNA-binding domain (DBD, C-domain), but its structure, and even its existence as a functional unit, are controversial. The D domain is poorly conserved throughout the nuclear receptor family and was originally proposed to comprise an unfolded hinge that facilitates rotation between the LBD and the DBD. Previous TR LBD structures, however, have indicated that the true unstructured region is three to six amino acid residues long and that the D-domain N terminus folds into a short amphipathic alpha-helix (H0) contiguous with the DBD and that the C terminus of the D-domain comprises H1 and H2 of the LBD. Here, we solve structures of TR-LBDs in different crystal forms and show that the N terminus of the TRalpha D-domain can adopt two structures; it can either fold into an amphipathic helix that resembles TRbeta H0 or form an unstructured loop. H0 formation requires contacts with the AF-2 coactivator-binding groove of the neighboring TR LBD, which binds H0 sequences that resemble coactivator LXXLL motifs. Structural analysis of a liganded TR LBD with small angle X-ray scattering (SAXS) suggests that AF-2/H0 interactions mediate dimerization of this protein in solution. We propose that the TR D-domain has the potential to form functionally important extensions of the DBD and LBD or unfold to permit TRs to adapt to different DNA response elements. We also show that mutations of the D domain LXXLL-like motif indeed selectively inhibit TR interactions with an inverted palindromic response element (F2) in vitro and TR activity at this response element in cell-based transfection experiments.
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Affiliation(s)
- Alessandro S Nascimento
- Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São Carlense, 400 CEP 13560-970 São Carlos, SP, Brazil
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94
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Martínez L, Webb P, Polikarpov I, Skaf MS. Molecular Dynamics Simulations of Ligand Dissociation from Thyroid Hormone Receptors: Evidence of the Likeliest Escape Pathway and Its Implications for the Design of Novel Ligands. J Med Chem 2005; 49:23-6. [PMID: 16392786 DOI: 10.1021/jm050805n] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Steered molecular dynamics simulations of ligand dissociation from Thyroid hormone receptors indicate that dissociation is favored via rearrangements in a mobile part of the LBD comprising H3, the loop between H1 and H2, and nearby beta-sheets, contrary to current models in which the H12 is mostly involved. Dissociation is facilitated in this path by the interaction of the hydrophilic part of the ligand with external water molecules, suggesting strategies to enhance ligand binding affinity.
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Affiliation(s)
- Leandro Martínez
- Instituto de Química, Universidade Estadual de Campinas - UNICAMP Cx. P. 6154, Campinas, SP 13084-862, Brazil
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95
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96
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Martínez L, Sonoda MT, Webb P, Baxter JD, Skaf MS, Polikarpov I. Molecular dynamics simulations reveal multiple pathways of ligand dissociation from thyroid hormone receptors. Biophys J 2005; 89:2011-23. [PMID: 15980170 PMCID: PMC1366704 DOI: 10.1529/biophysj.105.063818] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Accepted: 06/09/2005] [Indexed: 11/18/2022] Open
Abstract
Nuclear receptor (NR) ligands occupy a pocket that lies within the core of the NR ligand-binding domain (LBD), and most NR LBDs lack obvious entry/exit routes upon the protein surface. Thus, significant NR conformational rearrangements must accompany ligand binding and release. The precise nature of these processes, however, remains poorly understood. Here, we utilize locally enhanced sampling (LES) molecular dynamics computer simulations to predict molecular motions of x-ray structures of thyroid hormone receptor (TR) LBDs and determine events that permit ligand escape. We find that the natural ligand 3,5,3'-triiodo-L-thyronine (T(3)) dissociates from the TRalpha1 LBD along three competing pathways generated through i), opening of helix (H) 12; ii), separation of H8 and H11 and the Omega-loop between H2 and H3; and iii), opening of H2 and H3, and the intervening beta-strand. Similar pathways are involved in dissociation of T(3) and the TRbeta-selective ligand GC24 from TRbeta; the TR agonist IH5 from the alpha- and beta-TR forms; and Triac from two natural human TRbeta mutants, A317T and A234T, but are detected with different frequencies in simulations performed with the different structures. Path I was previously suggested to represent a major pathway for NR ligand dissociation. We propose here that Paths II and III are also likely ligand escape routes for TRs and other NRs. We also propose that different escape paths are preferred in different situations, implying that it will be possible to design NR ligands that only associate stably with their cognate receptors in specific cellular contexts.
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Affiliation(s)
- Leandro Martínez
- Instituto de Química, Universidade Estadual de Campinas, Campinas SP 13084-862, Brazil
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97
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Togashi M, Nguyen P, Fletterick R, Baxter JD, Webb P. Rearrangements in Thyroid Hormone Receptor Charge Clusters That StabilizeBound 3,5′,5-Triiodo-L-thyronine and Inhibit HomodimerFormation. J Biol Chem 2005; 280:25665-73. [PMID: 15886199 DOI: 10.1074/jbc.m501615200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this study, we investigated how thyroid hormone (3,5',5-triiodo-l-thyronine, T3) inhibits binding of thyroid hormone receptor (TR) homodimers, but not TR-retinoid X receptor heterodimers, to thyroid hormone response elements. Specifically we asked why a small subset of TRbeta mutations that arise in resistance to thyroid hormone syndrome inhibit both T3 binding and formation of TRbeta homodimers on thyroid hormone response elements. We reasoned that these mutations may affect structural elements involved in the coupling of T3 binding to inhibition of TR DNA binding activity. Analysis of TR x-ray structures revealed that each of these resistance to thyroid hormone syndrome mutations affects a cluster of charged amino acids with potential for ionic bond formation between oppositely charged partners. Two clusters (1 and 2) are adjacent to the dimer surface at the junction of helices 10 and 11. Targeted mutagenesis of residues in Cluster 1 (Arg338, Lys342, Asp351, and Asp355) and Cluster 2 (Arg429, Arg383, and Glu311) confirmed that the clusters are required for stable T3 binding and for optimal TR homodimer formation on DNA but also revealed that different arrangements of charged residues are needed for these effects. We propose that the charge clusters are homodimer-specific extensions of the dimer surface and further that T3 binding promotes specific rearrangements of these surfaces that simultaneously block homodimer formation on DNA and stabilize the bound hormone. Our data yield insight into the way that T3 regulates TR DNA binding activity and also highlight hitherto unsuspected T3-dependent conformational changes in the receptor ligand binding domain.
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Affiliation(s)
- Marie Togashi
- Diabetes Center and the Department of Biochemistry and Biophysics, University of California, San Francisco, California 94143-0540, USA
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98
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Miyabara EH, Aoki MS, Soares AG, Saltao RM, Vilicev CM, Passarelli M, Scanlan TS, Gouveia CH, Moriscot AS. Thyroid hormone receptor-β-selective agonist GC-24 spares skeletal muscle type I to II fiber shift. Cell Tissue Res 2005; 321:233-41. [PMID: 15947969 DOI: 10.1007/s00441-005-1119-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2004] [Accepted: 03/09/2005] [Indexed: 10/25/2022]
Abstract
Triiodothyronine (T3) is known to play a key role in the function of several tissues/organs via the thyroid hormone receptor isoforms alpha (TRalpha) and beta (TRbeta). We have investigated the effects of GC-24, a novel synthetic TRbeta-selective compound, on skeletal muscle fiber-type determination, cross-sectional area, and gene expression in rat skeletal muscles. For fiber typing, cross sections of soleus and extensor digitorum longus (EDL) muscles were stained for myosin ATPase activity at various pHs. Serum T3, T4, and cholesterol levels were also determined. Analysis of highly T3-responsive genes, viz., myosin heavy chain IIa (MHCIIa) and sarcoendoplasmic reticulum adenosine triphosphatase (SERCA1), was performed by quantitative real-time polymerase chain reaction. Equimolar doses of T3 and GC-24 had a similar cholesterol-lowering effect. T3, but not GC-24, decreased fiber type I and increased fiber type II abundance in soleus and EDL muscles. Conversely, in EDL, both T3 and GC-24 decreased the mean cross-sectional area of type I fibers. MHCIIa gene expression was reduced (approximately 50%) by T3 and unchanged by GC-24. SERCA1 gene expression was strongly induced by T3 (approximately 20-fold) and mildly induced by GC-24 (approximately two-fold). These results show that GC-24 does not significantly alter the composition of skeletal muscle fiber type and further strengthens the putative use of GC compounds as therapeutic agents.
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MESH Headings
- Acetates/pharmacology
- Acetates/therapeutic use
- Animals
- Benzhydryl Compounds/pharmacology
- Benzhydryl Compounds/therapeutic use
- Calcium-Transporting ATPases/genetics
- Cell Differentiation/drug effects
- Cell Differentiation/physiology
- Cell Size/drug effects
- Cholesterol/metabolism
- Gene Expression/drug effects
- Gene Expression/physiology
- Muscle Fibers, Fast-Twitch/drug effects
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Slow-Twitch/drug effects
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle, Skeletal/cytology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Myosin Heavy Chains/genetics
- Phenotype
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Sarcoplasmic Reticulum Calcium-Transporting ATPases
- Thyroid Hormone Receptors beta/agonists
- Thyroid Hormone Receptors beta/metabolism
- Triiodothyronine/adverse effects
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Affiliation(s)
- Elen H Miyabara
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of Sao Paulo, Brazil
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99
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Haning H, Woltering M, Mueller U, Schmidt G, Schmeck C, Voehringer V, Kretschmer A, Pernerstorfer J. Novel heterocyclic thyromimetics. Bioorg Med Chem Lett 2005; 15:1835-40. [PMID: 15780617 DOI: 10.1016/j.bmcl.2005.02.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Revised: 02/07/2005] [Accepted: 02/08/2005] [Indexed: 11/29/2022]
Abstract
Novel heterocycle-fused thyromimetics are presented carrying indoles or indazoles instead of the phenolic group in T3. Potent agonists were identified in both series. SAR trends are examined and found to be mostly consistent with previously published thyromimetics. Moderate THRbeta selectivity (approx. 10-fold) was observed in the indole series using isoform-selective transient THR transfection assays.
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Affiliation(s)
- Helmut Haning
- BAYER HealthCare AG, Business Group Pharma, D-42096 Wuppertal, Germany.
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Abstract
Nuclear receptors modulate transcription through ligand-mediated recruitment of transcriptional coregulator proteins. The structural connection between ligand and coregulator is mediated by a molecular switch, made up of the most carboxy-terminal helix in the ligand-binding domain, helix 12. The dynamics of this switch are thought to underlie ligand specificity of nuclear receptor signaling, but the details of this control mechanism have remained elusive. This review highlights recent structural work on how the ligand controls this molecular switch and the modulation of this signaling pathway by receptor subtype and dimer partner.
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Affiliation(s)
- Kendall W Nettles
- The University of Chicago, The Ben May Institute for Cancer Research, Chicago, Illinois 60637, USA.
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