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Latif R, Davies TF, Mezei M. Functional Water Channels Within the TSH Receptor: A New Paradigm for TSH Action With Disease Implications. Endocrinology 2023; 164:bqad146. [PMID: 37767722 DOI: 10.1210/endocr/bqad146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/20/2023] [Accepted: 09/25/2023] [Indexed: 09/29/2023]
Abstract
The thyroid-stimulating hormone receptor (TSHR) transmembrane domain (TMD) is found in the plasma membrane and consists of lipids and water molecules. To understand the role of TSHR-associated water molecules, we used molecular dynamic simulations of the TMD and identified a network of putative receptor-associated transmembrane water channels. This result was confirmed with extended simulations of the full-length TSHR with and without TSH ligand binding. While the transport time observed in the simulations via the TSHR protein was slower than via the lipid bilayer itself, we found that significantly more water traversed via the TSHR than via the lipid bilayer, which more than doubled with the binding of TSH. Using rat thyroid cells (FRTL-5) and a calcein fluorescence technique, we measured cell volumes after blockade of aquaporins 1 and 4, the major thyroid cell water transporters. TSH showed a dose-dependent ability to influence water transport, and similar effects were observed with stimulating TSHR autoantibodies. Small molecule TSHR agonists, which are allosteric activators of the TMD, also enhanced water transport, illustrating the role of the TMD in this phenomenon. Furthermore, the water channel pathway was also mapped across 2 activation motifs within the TSHR TMD, suggesting how water movement may influence activation of the receptor. In pathophysiological conditions such as hypothyroidism and hyperthyroidism where TSH concentrations are highly variable, this action of TSH may greatly influence water movement in thyroid cells and many other extrathyroidal sites where the TSHR is expressed, thus affecting normal cellular function.
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Affiliation(s)
- Rauf Latif
- Thyroid Research Unit, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- James J. Peters VA Medical Center, Thyroid Research Unit, New York, NY 10468, USA
| | - Terry F Davies
- Thyroid Research Unit, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- James J. Peters VA Medical Center, Thyroid Research Unit, New York, NY 10468, USA
| | - Mihaly Mezei
- Thyroid Research Unit, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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2
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Mezei M, Latif R, Davies TF. Modeling TSH Receptor Dimerization at the Transmembrane Domain. Endocrinology 2022; 163:6759649. [PMID: 36223484 PMCID: PMC9761578 DOI: 10.1210/endocr/bqac168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Indexed: 01/26/2023]
Abstract
Biophysical studies have established that the thyrotropin (TSH) receptor (TSHR) undergoes posttranslational modifications including dimerization. Following our earlier simulation of a TSHR-transmembrane domain (TMD) monomer (called TSHR-TMD-TRIO) we have now proceeded with a molecular dynamics simulation (MD) of TSHR-TMD dimerization using this improved membrane-embedded model. The starting structure was the TMD protein with all extracellular and intracellular loops and internal waters, which was placed in the relative orientation of the model originally generated with Brownian dynamics. Furthermore, this model was embedded in a DPPC lipid bilayer further solvated with water and added salt. Data from the MD simulation studies showed that the dimeric subunits stayed in the same relative orientation and distance during the 1000 ns of study. Comparison of representative conformations of the individual monomers when dimerized with the conformations from the monomer simulation showed subtle differences as represented by the backbone root mean square deviations. Differences in the conformations of the ligand-binding sites, suggesting variable affinities for these "hot spots," were also revealed by comparing the docking scores of 46 small-molecule ligands that included known TSHR agonists and antagonists as well as their derivatives. These data add further insight into the tendency of the TSHR-TMD to form dimeric and oligomeric structures and show that the differing conformations influence small-molecule binding sites within the TMD.
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Affiliation(s)
- Mihaly Mezei
- Correspondence: Mihaly Mezei, PhD, Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Pl, New York, NY 10029, USA.
| | - Rauf Latif
- Thyroid Research Unit, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
- Department of Medicine, James J. Peters VA Medical Center, New York, New York 10468, USA
| | - Terry F Davies
- Thyroid Research Unit, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
- Department of Medicine, James J. Peters VA Medical Center, New York, New York 10468, USA
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3
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Lorigo M, Cairrao E. Fetoplacental vasculature as a model to study human cardiovascular endocrine disruption. Mol Aspects Med 2021; 87:101054. [PMID: 34839931 DOI: 10.1016/j.mam.2021.101054] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 10/15/2021] [Accepted: 11/18/2021] [Indexed: 12/11/2022]
Abstract
Increasing evidence has associated the exposure of endocrine-disrupting chemicals (EDCs) with the cardiovascular (CV) system. This exposure is particularly problematic in a sensitive window of development, pregnancy. Pregnancy exposome can affect the overall health of the pregnancy by dramatic changes in vascular physiology and endocrine activity, increasing maternal susceptibility. Moreover, fetoplacental vascular function is generally altered, increasing the risk of developing pregnancy complications (including cardiovascular diseases, CVD) and predisposing the foetus to adverse health risks later in life. Thus, our review summarizes the existing literature on exposures to EDCs during pregnancy and adverse maternal health outcomes, focusing on the human placenta, vein, and umbilical artery associated with pregnancy complications. The purpose of this review is to highlight the role of fetoplacental vasculature as a model for the study of human cardiovascular endocrine disruption. Therefore, we emphasize that the placenta, together with the umbilical arteries and veins, allows a better characterization of the pregnant woman's exposome. Consequently, it contributes to the protection of the mother and foetus against CV disorders in life.
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Affiliation(s)
- Margarida Lorigo
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506, Covilhã, Portugal; FCS - UBI, Faculty of Health Sciences, University of Beira Interior, Covilhã, Portugal
| | - Elisa Cairrao
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506, Covilhã, Portugal; FCS - UBI, Faculty of Health Sciences, University of Beira Interior, Covilhã, Portugal.
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4
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Kim SM, Ryu V, Miyashita S, Korkmaz F, Lizneva D, Gera S, Latif R, Davies TF, Iqbal J, Yuen T, Zaidi M. Thyrotropin, Hyperthyroidism, and Bone Mass. J Clin Endocrinol Metab 2021; 106:e4809-e4821. [PMID: 34318885 PMCID: PMC8864741 DOI: 10.1210/clinem/dgab548] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Thyrotropin (TSH), traditionally seen as a pituitary hormone that regulates thyroid glands, has additional roles in physiology including skeletal remodeling. Population-based observations in people with euthyroidism or subclinical hyperthyroidism indicated a negative association between bone mass and low-normal TSH. The findings of correlative studies were supported by small intervention trials using recombinant human TSH (rhTSH) injection, and genetic and case-based evidence. Genetically modified mouse models, which disrupt the reciprocal relationship between TSH and thyroid hormone, have allowed us to examine an independent role of TSH. Since the first description of osteoporotic phenotype in haploinsufficient Tshr +/- mice with normal thyroid hormone levels, the antiosteoclastic effect of TSH has been documented in both in vitro and in vivo studies. Further studies showed that increased osteoclastogenesis in Tshr-deficient mice was mediated by tumor necrosis factor α. Low TSH not only increased osteoclastogenesis, but also decreased osteoblastogenesis in bone marrow-derived primary osteoblast cultures. However, later in vivo studies using small and intermittent doses of rhTSH showed a proanabolic effect, which suggests that its action might be dose and frequency dependent. TSHR was shown to interact with insulin-like growth factor 1 receptor, and vascular endothelial growth factor and Wnt pathway might play a role in TSH's effect on osteoblasts. The expression and direct skeletal effect of a biologically active splice variant of the TSHβ subunit (TSHβv) in bone marrow-derived macrophage and other immune cells suggest a local skeletal effect of TSHR. Further studies of how locally secreted TSHβv and systemic TSHβ interact in skeletal remodeling through the endocrine, immune, and skeletal systems will help us better understand the hyperthyroidism-induced bone disease.
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Affiliation(s)
- Se-Min Kim
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and of Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Vitaly Ryu
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and of Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sari Miyashita
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and of Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Funda Korkmaz
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and of Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Daria Lizneva
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and of Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sakshi Gera
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and of Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Rauf Latif
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and of Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Terry F Davies
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and of Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jameel Iqbal
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and of Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Tony Yuen
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and of Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Mone Zaidi
- The Mount Sinai Bone Program, Departments of Pharmacological Sciences and of Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Correspondence: The Mount Sinai Bone Program, Departments of Pharmacological Sciences and Medicine, and Center of Translational Medicine and Pharmacology, Icahn School of Medicine at Mount Sinai, 1428 Madison Avenue, 4th Floor, Box 1055, New York, NY 10029, USA.
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Mezei M, Latif R, Das B, Davies TF. Implications of an Improved Model of the TSH Receptor Transmembrane Domain (TSHR-TMD-TRIO). Endocrinology 2021; 162:6161546. [PMID: 33693584 PMCID: PMC8183494 DOI: 10.1210/endocr/bqab051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Indexed: 11/19/2022]
Abstract
The thyroid-stimulating hormone receptor (TSHR) is a G-protein-coupled receptor group A family member with 7 transmembrane helices. We generated 3 new models of its entire transmembrane region using a 600 ns molecular simulation. The simulation started from our previously published model, which we have now revised by also modeling the intracellular loops and the C-terminal tail, adding internal waters and embedding it into a lipid bilayer with a water layer and with ions added to complete the system. We have named this model TSHR-TMD-TRIO since 3 representative dominant structures were then extracted from the simulation trajectory and compared with the original model. These structures each showed small but significant changes in the relative positions of the helices. The 3 models were also used as targets to dock a set of small molecules that are known active compounds including a new TSHR antagonist (BT362), which confirmed the appropriateness of the model with some small molecules showing significant preference for one or other of the structures.
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Affiliation(s)
- Mihaly Mezei
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Correspondence: Mihaly Mezei, PhD, Icahn School of Medicine at Mount Sinai, New York, NY, USA. E-mail:
| | - Rauf Latif
- Thyroid Research Unit, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- James J. Peters VA Medical Center, New York, NY, USA
| | - Bhaskar Das
- Arnold & Marie Schwartz College of Pharmacy & Health Sciences, Long Island University, New York, NY, USA
| | - Terry F Davies
- Thyroid Research Unit, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- James J. Peters VA Medical Center, New York, NY, USA
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UV-B Filter Octylmethoxycinnamate Alters the Vascular Contractility Patterns in Pregnant Women with Hypothyroidism. Biomedicines 2021; 9:biomedicines9020115. [PMID: 33530401 PMCID: PMC7912698 DOI: 10.3390/biomedicines9020115] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 02/06/2023] Open
Abstract
Increasing evidence relating the exposure and/or bioaccumulation of endocrine-disrupting compounds (EDCs) with cardiovascular system are arising. Octylmethoxycinnamate (OMC) is the most widely used UV-B filter and as EDC interacts with TH receptors. However, their effects on thyroid diseases during pregnancy remain unknown. The purpose of this work was to assess the short- and long-term effects of OMC on arterial tonus of pregnant women with hypothyroidism. To elucidate this, human umbilical artery (HUA) rings without endothelium were used to explore the vascular effects of OMC by arterial and cellular experiments. The binding energy and the modes of interaction of the OMC into the active center of the TSHR and THRα were analyzed by molecular docking studies. Our results indicated that OMC altered the contractility patterns of HUA contracted with serotonin, histamine and KCl, possibly due to an interference with serotonin and histamine receptors or an involvement of the Ca2+ channels. The molecular docking analysis show that OMC compete with T3 for the binding center of THRα. Taken together, these findings pointed out to alterations in HUA reactivity as result of OMC-exposure, which may be involved in the development and increased risk of cardiovascular diseases.
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Latif R, Morshed SA, Ma R, Tokat B, Mezei M, Davies TF. A Gq Biased Small Molecule Active at the TSH Receptor. Front Endocrinol (Lausanne) 2020; 11:372. [PMID: 32676053 PMCID: PMC7333667 DOI: 10.3389/fendo.2020.00372] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/11/2020] [Indexed: 11/13/2022] Open
Abstract
G protein coupled receptors (GPCRs) can lead to G protein and non-G protein initiated signals. By virtue of its structural property, the TSH receptor (TSHR) has a unique ability to engage different G proteins making it highly amenable to selective signaling. In this study, we describe the identification and characterization of a novel small molecule agonist to the TSHR which induces primary engagement with Gαq/11. To identify allosteric modulators inducing selective signaling of the TSHR we used a transcriptional-based luciferase assay system with CHO-TSHR cells stably expressing response elements (CRE, NFAT, SRF, or SRE) that were capable of measuring signals emanating from the coupling of Gαs , Gαq/11, Gβγ, and Gα12/13, respectively. Using this system, TSH activated Gαs , Gαq/11, and Gα12/13 but not Gβγ. On screening a library of 50K molecules at 0.1,1.0 and 10 μM, we identified a novel Gq/11 agonist (named MSq1) which activated Gq/11 mediated NFAT-luciferase >4 fold above baseline and had an EC50= 8.3 × 10-9 M with only minor induction of Gαs and cAMP. Furthermore, MSq1 is chemically and structurally distinct from any of the previously reported TSHR agonist molecules. Docking studies using a TSHR transmembrane domain (TMD) model indicated that MSq1 had contact points on helices H1, H2, H3, and H7 in the hydrophobic pocket of the TMD and also with the extracellular loops. On co-treatment with TSH, MSq1 suppressed TSH-induced proliferation of thyrocytes in a dose-dependent manner but lacked the intrinsic ability to influence basal thyrocyte proliferation. This unexpected inhibitory property of MSq1 could be blocked in the presence of a PKC inhibitor resulting in derepressing TSH induced protein kinase A (PKA) signals and resulting in the induction of proliferation. Thus, the inhibitory effect of MSq1 on proliferation resided in its capacity to overtly activate protein kinase C (PKC) which in turn suppressed the proliferative signal induced by activation of the predomiant cAMP-PKA pathway of the TSHR. Treatment of rat thyroid cells (FRTL5) with MSq1 did not show any upregulation of gene expression of the key thyroid specific markers such as thyroglobulin(Tg), thyroid peroxidase (Tpo), sodium iodide symporter (Nis), and the TSH receptor (Tshr) further suggesting lack of involvement of MSq1 and Gαq/11 activation with cellular differentation. In summary, we identified and characterized a novel Gαq/11 agonist molecule acting at the TSHR and which showed a marked anti-proliferative ability. Hence, Gq biased activation of the TSHR is capable of ameliorating the proliferative signals from its orthosteric ligand and may offer a therapeutic option for thyroid growth modulation.
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Affiliation(s)
- Rauf Latif
- Thyroid Research Unit, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- James J. Peters VA Medical Center, New York, NY, United States
- *Correspondence: Rauf Latif
| | - Syed A. Morshed
- Thyroid Research Unit, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- James J. Peters VA Medical Center, New York, NY, United States
| | - Risheng Ma
- Thyroid Research Unit, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- James J. Peters VA Medical Center, New York, NY, United States
| | - Bengu Tokat
- Thyroid Research Unit, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Mihaly Mezei
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Terry F. Davies
- Thyroid Research Unit, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- James J. Peters VA Medical Center, New York, NY, United States
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Basavanhally T, Fonseca R, Uversky VN. Born This Way: Using Intrinsic Disorder to Map the Connections between SLITRKs, TSHR, and Male Sexual Orientation. Proteomics 2018; 18:e1800307. [PMID: 30156382 DOI: 10.1002/pmic.201800307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/03/2018] [Indexed: 12/15/2022]
Abstract
Recently, genome-wide association study reveals a significant association between specific single nucleotide polymorphisms (SNPs) in men and their sexual orientation. These SNPs (rs9547443 and rs1035144) reside in the intergenic region between the SLITRK5 and SLITRK6 genes and in the intronic region of the TSHR gene and might affect functionality of SLITRK5, SLITRK6, and TSHR proteins that are engaged in tight control of key developmental processes, such as neurite outgrowth and modulation, cellular differentiation, and hormonal regulation. SLITRK5 and SLITRK6 are single-pass transmembrane proteins, whereas TSHR is a heptahelical G protein-coupled receptor (GPCR). Mutations in these proteins are associated with various diseases and are linked to phenotypes found at a higher rate in homosexual men. A bioinformatics analysis of SLITRK5, SLITRK6, and TSHR proteins is conducted to look at their structure, protein interaction networks, and propensity for intrinsic disorder. It is assumed that this information might improve understanding of the roles that SLITRK5, SLITRK6, and TSHR play within neuronal and thyroidal tissues and give insight into the phenotypes associated with male homosexuality.
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Affiliation(s)
- Tara Basavanhally
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Renée Fonseca
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA.,USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA.,Protein Research Group, Institute for Biological Instrumentation of the Russian Academy of Sciences, 142290, Pushchino, Moscow, Russia
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Allen B, Mehta S, Ember SWJ, Zhu JY, Schönbrunn E, Ayad NG, Schürer SC. Identification of a Novel Class of BRD4 Inhibitors by Computational Screening and Binding Simulations. ACS OMEGA 2017; 2:4760-4771. [PMID: 28884163 PMCID: PMC5579542 DOI: 10.1021/acsomega.7b00553] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/27/2017] [Indexed: 06/07/2023]
Abstract
Computational screening is a method to prioritize small-molecule compounds based on the structural and biochemical attributes built from ligand and target information. Previously, we have developed a scalable virtual screening workflow to identify novel multitarget kinase/bromodomain inhibitors. In the current study, we identified several novel N-[3-(2-oxo-pyrrolidinyl)phenyl]-benzenesulfonamide derivatives that scored highly in our ensemble docking protocol. We quantified the binding affinity of these compounds for BRD4(BD1) biochemically and generated cocrystal structures, which were deposited in the Protein Data Bank. As the docking poses obtained in the virtual screening pipeline did not align with the experimental cocrystal structures, we evaluated the predictions of their precise binding modes by performing molecular dynamics (MD) simulations. The MD simulations closely reproduced the experimentally observed protein-ligand cocrystal binding conformations and interactions for all compounds. These results suggest a computational workflow to generate experimental-quality protein-ligand binding models, overcoming limitations of docking results due to receptor flexibility and incomplete sampling, as a useful starting point for the structure-based lead optimization of novel BRD4(BD1) inhibitors.
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Affiliation(s)
- Bryce
K. Allen
- Department
of Molecular and Cellular Pharmacology, Miller School
of Medicine, Center for Computational Science, Center for Therapeutic Innovation Miller School
of Medicine, Miami Project to Cure Paralysis, Department of Psychiatry and Behavioral
Sciences, Miller School of Medicine, and Sylvester Comprehensive Cancer Center,
Miller School of Medicine, University of
Miami, Miami, Florida 33136, United States
| | - Saurabh Mehta
- Department
of Molecular and Cellular Pharmacology, Miller School
of Medicine, Center for Computational Science, Center for Therapeutic Innovation Miller School
of Medicine, Miami Project to Cure Paralysis, Department of Psychiatry and Behavioral
Sciences, Miller School of Medicine, and Sylvester Comprehensive Cancer Center,
Miller School of Medicine, University of
Miami, Miami, Florida 33136, United States
- Department
of Applied Chemistry, Delhi
Technological University, Delhi 110042, India
| | - Stuart W. J. Ember
- Drug
Discovery Department, H. Lee Moffitt Cancer
Center and Research Institute, Tampa, Florida 33612-9416, United States
| | - Jin-Yi Zhu
- Drug
Discovery Department, H. Lee Moffitt Cancer
Center and Research Institute, Tampa, Florida 33612-9416, United States
| | - Ernst Schönbrunn
- Drug
Discovery Department, H. Lee Moffitt Cancer
Center and Research Institute, Tampa, Florida 33612-9416, United States
| | - Nagi G. Ayad
- Department
of Molecular and Cellular Pharmacology, Miller School
of Medicine, Center for Computational Science, Center for Therapeutic Innovation Miller School
of Medicine, Miami Project to Cure Paralysis, Department of Psychiatry and Behavioral
Sciences, Miller School of Medicine, and Sylvester Comprehensive Cancer Center,
Miller School of Medicine, University of
Miami, Miami, Florida 33136, United States
| | - Stephan C. Schürer
- Department
of Molecular and Cellular Pharmacology, Miller School
of Medicine, Center for Computational Science, Center for Therapeutic Innovation Miller School
of Medicine, Miami Project to Cure Paralysis, Department of Psychiatry and Behavioral
Sciences, Miller School of Medicine, and Sylvester Comprehensive Cancer Center,
Miller School of Medicine, University of
Miami, Miami, Florida 33136, United States
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10
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Kleinau G, Worth CL, Kreuchwig A, Biebermann H, Marcinkowski P, Scheerer P, Krause G. Structural-Functional Features of the Thyrotropin Receptor: A Class A G-Protein-Coupled Receptor at Work. Front Endocrinol (Lausanne) 2017; 8:86. [PMID: 28484426 PMCID: PMC5401882 DOI: 10.3389/fendo.2017.00086] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 04/03/2017] [Indexed: 12/21/2022] Open
Abstract
The thyroid-stimulating hormone receptor (TSHR) is a member of the glycoprotein hormone receptors, a sub-group of class A G-protein-coupled receptors (GPCRs). TSHR and its endogenous ligand thyrotropin (TSH) are of essential importance for growth and function of the thyroid gland and proper function of the TSH/TSHR system is pivotal for production and release of thyroid hormones. This receptor is also important with respect to pathophysiology, such as autoimmune (including ophthalmopathy) or non-autoimmune thyroid dysfunctions and cancer development. Pharmacological interventions directly targeting the TSHR should provide benefits to disease treatment compared to currently available therapies of dysfunctions associated with the TSHR or the thyroid gland. Upon TSHR activation, the molecular events conveying conformational changes from the extra- to the intracellular side of the cell across the membrane comprise reception, conversion, and amplification of the signal. These steps are highly dependent on structural features of this receptor and its intermolecular interaction partners, e.g., TSH, antibodies, small molecules, G-proteins, or arrestin. For better understanding of signal transduction, pathogenic mechanisms such as autoantibody action and mutational modifications or for developing new pharmacological strategies, it is essential to combine available structural data with functional information to generate homology models of the entire receptor. Although so far these insights are fragmental, in the past few decades essential contributions have been made to investigate in-depth the involved determinants, such as by structure determination via X-ray crystallography. This review summarizes available knowledge (as of December 2016) concerning the TSHR protein structure, associated functional aspects, and based on these insights we suggest several receptor complex models. Moreover, distinct TSHR properties will be highlighted in comparison to other class A GPCRs to understand the molecular activation mechanisms of this receptor comprehensively. Finally, limitations of current knowledge and lack of information are discussed highlighting the need for intensified efforts toward TSHR structure elucidation.
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Affiliation(s)
- Gunnar Kleinau
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin, Berlin, Germany
- Group Protein X-Ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Charité-Universitätsmedizin, Berlin, Germany
| | | | - Annika Kreuchwig
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin, Berlin, Germany
| | | | - Patrick Scheerer
- Group Protein X-Ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Charité-Universitätsmedizin, Berlin, Germany
| | - Gerd Krause
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Berlin, Germany
- *Correspondence: Gerd Krause,
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Núñez Miguel R, Sanders J, Furmaniak J, Smith BR. Structure and activation of the TSH receptor transmembrane domain. AUTOIMMUNITY HIGHLIGHTS 2016; 8:2. [PMID: 27921237 PMCID: PMC5136658 DOI: 10.1007/s13317-016-0090-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 11/23/2016] [Indexed: 12/30/2022]
Abstract
PURPOSE The thyroid-stimulating hormone receptor (TSHR) is the target autoantigen for TSHR-stimulating autoantibodies in Graves' disease. The TSHR is composed of: a leucine-rich repeat domain (LRD), a hinge region or cleavage domain (CD) and a transmembrane domain (TMD). The binding arrangements between the TSHR LRD and the thyroid-stimulating autoantibody M22 or TSH have become available from the crystal structure of the TSHR LRD-M22 complex and a comparative model of the TSHR LRD in complex with TSH, respectively. However, the mechanism by which the TMD of the TSHR and the other glycoprotein hormone receptors (GPHRs) becomes activated is unknown. METHODS We have generated comparative models of the structures of the inactive (TMD_In) and active (TMD_Ac) conformations of the TSHR, follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) TMDs. The structures of TMD_Ac and TMD_In were obtained using class A GPCR crystal structures for which fully active and inactive conformations were available. RESULTS Most conserved motifs observed in GPCR TMDs are also observed in the amino acid sequences of GPHR TMDs. Furthermore, most GPCR TMD conserved helix distortions are observed in our models of the structures of GPHR TMDs. Analysis of these structures has allowed us to propose a mechanism for activation of GPHR TMDs. CONCLUSIONS Insight into the mechanism of activation of the TSHR by both TSH and TSHR autoantibodies is likely to be useful in the development of new treatments for Graves' disease.
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Affiliation(s)
| | - Jane Sanders
- FIRS Laboratories, RSR Ltd, Parc Ty Glas, Llanishen, Cardiff, CF14 5DU, UK
| | - Jadwiga Furmaniak
- FIRS Laboratories, RSR Ltd, Parc Ty Glas, Llanishen, Cardiff, CF14 5DU, UK
| | - Bernard Rees Smith
- FIRS Laboratories, RSR Ltd, Parc Ty Glas, Llanishen, Cardiff, CF14 5DU, UK.
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Latif R, Realubit RB, Karan C, Mezei M, Davies TF. TSH Receptor Signaling Abrogation by a Novel Small Molecule. Front Endocrinol (Lausanne) 2016; 7:130. [PMID: 27729899 PMCID: PMC5037132 DOI: 10.3389/fendo.2016.00130] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/06/2016] [Indexed: 12/19/2022] Open
Abstract
Pathological activation of the thyroid-stimulating hormone receptor (TSHR) is caused by thyroid-stimulating antibodies in patients with Graves' disease (GD) or by somatic and rare genomic mutations that enhance constitutive activation of the receptor influencing both G protein and non-G protein signaling. Potential selective small molecule antagonists represent novel therapeutic compounds for abrogation of such abnormal TSHR signaling. In this study, we describe the identification and in vitro characterization of a novel small molecule antagonist by high-throughput screening (HTS). The identification of the TSHR antagonist was performed using a transcription-based TSH-inhibition bioassay. TSHR-expressing CHO cells, which also expressed a luciferase-tagged CRE response element, were optimized using bovine TSH as the activator, in a 384 well plate format, which had a Z score of 0.3-0.6. Using this HTS assay, we screened a diverse library of ~80,000 compounds at a final concentration of 16.7 μM. The selection criteria for a positive hit were based on a mean signal threshold of ≥50% inhibition of control TSH stimulation. The screening resulted in 450 positive hits giving a hit ratio of 0.56%. A secondary confirmation screen against TSH and forskolin - a post receptor activator of adenylyl cyclase - confirmed one TSHR-specific candidate antagonist molecule (named VA-K-14). This lead molecule had an IC50 of 12.3 μM and a unique chemical structure. A parallel analysis for cell viability indicated that the lead inhibitor was non-cytotoxic at its effective concentrations. In silico docking studies performed using a TSHR transmembrane model showed the hydrophobic contact locations and the possible mode of inhibition of TSHR signaling. Furthermore, this molecule was capable of inhibiting TSHR stimulation by GD patient sera and monoclonal-stimulating TSHR antibodies. In conclusion, we report the identification of a novel small molecule TSHR inhibitor, which has the potential to be developed as a therapeutic antagonist for abrogation of TSHR signaling by TSHR autoantibodies in GD.
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Affiliation(s)
- Rauf Latif
- Thyroid Research Unit, James J. Peters VA Medical Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- *Correspondence: Rauf Latif,
| | - Ronald B. Realubit
- Sulzberger Columbia Genome Center, Columbia University, New York, NY, USA
| | - Charles Karan
- Sulzberger Columbia Genome Center, Columbia University, New York, NY, USA
| | - Mihaly Mezei
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Terry F. Davies
- Thyroid Research Unit, James J. Peters VA Medical Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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13
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Abstract
The TSH receptor (TSHR) has the propensity to form dimers and oligomers. Our data using ectodomain-truncated TSHRs indicated that the predominant interfaces for oligomerization reside in the transmembrane (TM) domain. To map the potentially interacting residues, we first performed in silico studies of the TSHR transmembrane domain using a homology model and using Brownian dynamics (BD). The cluster of dimer conformations obtained from BD analysis indicated that TM1 made contact with TM4 and two residues in TM2 made contact with TM5. To confirm the proximity of these contact residues, we then generated cysteine mutants at all six contact residues predicted by the BD analysis and performed cysteine cross-linking studies. These results showed that the predicted helices in the protomer were indeed involved in proximity interactions. Furthermore, an alternative experimental approach, receptor truncation experiments and LH receptor sequence substitution experiments, identified TM1 harboring a major region involved in TSHR oligomerization, in agreement with the conclusion from the cross-linking studies. Point mutations of the predicted interacting residues did not yield a substantial decrease in oligomerization, unlike the truncation of the TM1, so we concluded that constitutive oligomerization must involve interfaces forming domains of attraction in a cooperative manner that is not dominated by interactions between specific residues.
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Affiliation(s)
- Rauf Latif
- Thyroid Research Unit (R.L., M.R.A., T.F.D.) and Departments of Medicine (R.L., M.R.A., T.F.D.) and Structural and Chemical Biology (M.M.), Icahn School of Medicine at Mt Sinai School of Medicine, New York, New York 10029; and James J. Peters Veterans Affairs Medical Center (R.L., M.R.A., T.F.D.), New York, New York 10468
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Latif R, Ali MR, Ma R, David M, Morshed SA, Ohlmeyer M, Felsenfeld DP, Lau Z, Mezei M, Davies TF. New small molecule agonists to the thyrotropin receptor. Thyroid 2015; 25:51-62. [PMID: 25333622 PMCID: PMC4291085 DOI: 10.1089/thy.2014.0119] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Novel small molecular ligands (SMLs) to the thyrotropin receptor (TSHR) have potential as improved molecular probes and as therapeutic agents for the treatment of thyroid dysfunction and thyroid cancer. METHODS To identify novel SMLs to the TSHR, we developed a transcription-based luciferase-cAMP high-throughput screening system and we screened 48,224 compounds from a 100K library in duplicate. RESULTS We obtained 62 hits using the cut-off criteria of the mean±three standard deviations above the baseline. Twenty molecules with the greatest activity were rescreened against the parent CHO-luciferase cell for nonspecific activation, and we selected two molecules (MS437 and MS438) with the highest potency for further study. These lead molecules demonstrated no detectible cross-reactivity with homologous receptors when tested against luteinizing hormone (LH)/human chorionic gonadotropin receptor and follicle stimulating hormone receptor-expressing cells. Molecule MS437 had a TSHR-stimulating potency with an EC50 of 13×10(-8) M, and molecule MS438 had an EC50 of 5.3×10(-8) M. The ability of these small molecule agonists to bind to the transmembrane domain of the receptor and initiate signal transduction was suggested by their activation of a chimeric receptor consisting of an LHR ectodomain and a TSHR transmembrane. Molecular modeling demonstrated that these molecules bound to residues S505 and E506 for MS438 and T501 for MS437 in the intrahelical region of transmembrane helix 3. We also examined the G protein activating ability of these molecules using CHO cells co-expressing TSHRs transfected with luciferase reporter vectors in order to measure Gsα, Gβγ, Gαq, and Gα12 activation quantitatively. The MS437 and MS438 molecules showed potent activation of Gsα, Gαq, and Gα12 similar to TSH, but neither the small molecule agonists nor TSH showed activation of the Gβγ pathway. The small molecules MS437 and MS438 also showed upregulation of thyroglobulin (Tg), sodium iodine symporter (NIS), and TSHR gene expression. CONCLUSIONS Pharmacokinetic analysis of MS437 and MS438 indicated their pharmacotherapeutic potential, and their intraperitoneal administration to normal female mice resulted in significantly increased serum thyroxine levels, which could be maintained by repeated treatments. These molecules can therefore serve as lead molecules for further development of powerful TSH agonists.
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Affiliation(s)
- Rauf Latif
- Thyroid Research Unit, Department of Medicine, Icahn School of Medicine at Mount Sinai and the James J. Peters VA Medical Center, New York, New York
| | - M. Rejwan Ali
- Thyroid Research Unit, Department of Medicine, Icahn School of Medicine at Mount Sinai and the James J. Peters VA Medical Center, New York, New York
| | - Risheng Ma
- Thyroid Research Unit, Department of Medicine, Icahn School of Medicine at Mount Sinai and the James J. Peters VA Medical Center, New York, New York
| | - Martine David
- Thyroid Research Unit, Department of Medicine, Icahn School of Medicine at Mount Sinai and the James J. Peters VA Medical Center, New York, New York
| | - Syed A. Morshed
- Thyroid Research Unit, Department of Medicine, Icahn School of Medicine at Mount Sinai and the James J. Peters VA Medical Center, New York, New York
| | - Michael Ohlmeyer
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Dan P. Felsenfeld
- Integrated Screening Core, Experimental Therapeutics Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Zerlina Lau
- Integrated Screening Core, Experimental Therapeutics Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Mihaly Mezei
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Terry F. Davies
- Thyroid Research Unit, Department of Medicine, Icahn School of Medicine at Mount Sinai and the James J. Peters VA Medical Center, New York, New York
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Cavasotto CN, Palomba D. Expanding the horizons of G protein-coupled receptor structure-based ligand discovery and optimization using homology models. Chem Commun (Camb) 2015; 51:13576-94. [DOI: 10.1039/c5cc05050b] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We show the key role of structural homology models in GPCR structure-based lead discovery and optimization, highlighting methodological aspects, recent progress and future directions.
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Affiliation(s)
- Claudio N. Cavasotto
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society
- Buenos Aires
- Argentina
| | - Damián Palomba
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society
- Buenos Aires
- Argentina
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