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Speck D, Kleinau G, Szczepek M, Kwiatkowski D, Catar R, Philippe A, Scheerer P. Angiotensin and Endothelin Receptor Structures With Implications for Signaling Regulation and Pharmacological Targeting. Front Endocrinol (Lausanne) 2022; 13:880002. [PMID: 35518926 PMCID: PMC9063481 DOI: 10.3389/fendo.2022.880002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 03/18/2022] [Indexed: 12/28/2022] Open
Abstract
In conjunction with the endothelin (ET) type A (ETAR) and type B (ETBR) receptors, angiotensin (AT) type 1 (AT1R) and type 2 (AT2R) receptors, are peptide-binding class A G-protein-coupled receptors (GPCRs) acting in a physiologically overlapping context. Angiotensin receptors (ATRs) are involved in regulating cell proliferation, as well as cardiovascular, renal, neurological, and endothelial functions. They are important therapeutic targets for several diseases or pathological conditions, such as hypertrophy, vascular inflammation, atherosclerosis, angiogenesis, and cancer. Endothelin receptors (ETRs) are expressed primarily in blood vessels, but also in the central nervous system or epithelial cells. They regulate blood pressure and cardiovascular homeostasis. Pathogenic conditions associated with ETR dysfunctions include cancer and pulmonary hypertension. While both receptor groups are activated by their respective peptide agonists, pathogenic autoantibodies (auto-Abs) can also activate the AT1R and ETAR accompanied by respective clinical conditions. To date, the exact mechanisms and differences in binding and receptor-activation mediated by auto-Abs as opposed to endogenous ligands are not well understood. Further, several questions regarding signaling regulation in these receptors remain open. In the last decade, several receptor structures in the apo- and ligand-bound states were determined with protein X-ray crystallography using conventional synchrotrons or X-ray Free-Electron Lasers (XFEL). These inactive and active complexes provide detailed information on ligand binding, signal induction or inhibition, as well as signal transduction, which is fundamental for understanding properties of different activity states. They are also supportive in the development of pharmacological strategies against dysfunctions at the receptors or in the associated signaling axis. Here, we summarize current structural information for the AT1R, AT2R, and ETBR to provide an improved molecular understanding.
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Affiliation(s)
- David Speck
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany
| | - Gunnar Kleinau
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany
| | - Michal Szczepek
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany
| | - Dennis Kwiatkowski
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany
| | - Rusan Catar
- Department of Nephrology and Critical Care Medicine, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Aurélie Philippe
- Department of Nephrology and Medical Intensive Care, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Center for Cardiovascular Research, Berlin, Germany
| | - Patrick Scheerer
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
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Vu O, Bender BJ, Pankewitz L, Huster D, Beck-Sickinger AG, Meiler J. The Structural Basis of Peptide Binding at Class A G Protein-Coupled Receptors. Molecules 2021; 27:molecules27010210. [PMID: 35011444 PMCID: PMC8746363 DOI: 10.3390/molecules27010210] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 12/15/2021] [Accepted: 12/18/2021] [Indexed: 11/16/2022] Open
Abstract
G protein-coupled receptors (GPCRs) represent the largest membrane protein family and a significant target class for therapeutics. Receptors from GPCRs’ largest class, class A, influence virtually every aspect of human physiology. About 45% of the members of this family endogenously bind flexible peptides or peptides segments within larger protein ligands. While many of these peptides have been structurally characterized in their solution state, the few studies of peptides in their receptor-bound state suggest that these peptides interact with a shared set of residues and undergo significant conformational changes. For the purpose of understanding binding dynamics and the development of peptidomimetic drug compounds, further studies should investigate the peptide ligands that are complexed to their cognate receptor.
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Affiliation(s)
- Oanh Vu
- Deparment of Chemistry, Vanderbilt University, Nashville, TN 37235, USA;
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; (B.J.B.); (L.P.)
| | - Brian Joseph Bender
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; (B.J.B.); (L.P.)
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - Lisa Pankewitz
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; (B.J.B.); (L.P.)
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, Medical Department, Leipzig University, Härtelstr. 16–18, D-04107 Leipzig, Germany;
| | - Annette G. Beck-Sickinger
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstr. 34, D-04103 Leipzig, Germany;
| | - Jens Meiler
- Deparment of Chemistry, Vanderbilt University, Nashville, TN 37235, USA;
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; (B.J.B.); (L.P.)
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
- Leipzig University Medical Center, Institute for Drug Discovery, Departments of Chemistry and Computer Science, Leipzig University, Brüderstr. 34, D-04103 Leipzig, Germany
- Correspondence:
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Dai Y, Chen X, Song X, Chen X, Ma W, Lin J, Wu H, Hu X, Zhou Y, Zhang H, Liao Y, Qiu Z, Zhou Z. Immunotherapy of Endothelin-1 Receptor Type A for Pulmonary Arterial Hypertension. J Am Coll Cardiol 2020; 73:2567-2580. [PMID: 31118151 DOI: 10.1016/j.jacc.2019.02.067] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 01/29/2019] [Accepted: 02/18/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND Pulmonary arterial hypertension (PAH) is a chronic fatal disease. The treatment of PAH is less than ideal and the control is far from satisfactory worldwide. Vaccination provides a promising approach for treatment of PAH. OBJECTIVES This study sought to find a vaccine against endothelin-1 (ET-1) receptor type A (ETAR) for treating PAH. METHODS The ETRQβ-002 vaccine was screened and the specific antibodies against epitope ETR-002 belonging to the second extracellular loop of ETAR (including the polyclonal and monoclonal antibody) were produced. The effect of the antibodies on Ca2+-dependent signal transduction events was investigated. In vivo, ETRQβ-002 vaccine was used to vaccinate monocrotaline (MCT)- and Sugen/hypoxia-induced pulmonary hypertension animals. The monoclonal antibody (mAb) against ETR-002 was also injected into the PAH animals. The effect of ETRQβ-002 vaccine on pulmonary hypertension and remodeling of pulmonary arterioles and right ventricle (RV) was carefully evaluated. Further, the possible immune-mediated damage was detected in normal vaccinated animals. RESULTS ETR-002 peptide has perfect immunogenicity and ETRQβ-002 vaccine could induce strong antibody production. In vitro, the anti-ETR-002 antibody bound to ETAR and inhibited Ca2+-dependent signal transduction events, including extracellular signal-regulated kinase phosphorylation and elevation of intracellular Ca2+ concentration induced by ET-1. In vivo, both ETRQβ-002 vaccine and the mAb significantly decreased the RV systolic pressure up to 20 mm Hg and 10 mm Hg in MCT-exposed rats and Sugen/hypoxia-exposed mice, respectively. Also, ETRQβ-002 vaccine/mAb obviously ameliorated pathological remodeling of pulmonary arterioles and hypertrophy of the RV in PAH animals. Additionally, no significant immune-mediated damage was detected in vaccinated animals. CONCLUSIONS ETRQβ-002 vaccine/mAb attenuated remodeling of pulmonary arterioles and RV in MCT- and Sugen/hypoxia-induced PAH animals and decreased RV systolic pressure effectively through diminishing the pressure response and inhibiting signal transduction initiated by ET-1. ETRQβ-002 vaccine/mAb may provide a novel and promising method for PAH treatment.
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Affiliation(s)
- Yong Dai
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiao Chen
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoxiao Song
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xijun Chen
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wenrui Ma
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jibin Lin
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hailang Wu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiajun Hu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yanzhao Zhou
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hongrong Zhang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuhua Liao
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhihua Qiu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Zihua Zhou
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Key Lab of Molecular Biological Targeted Therapies of the Ministry of Education, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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Shihoya W, Izume T, Inoue A, Yamashita K, Kadji FMN, Hirata K, Aoki J, Nishizawa T, Nureki O. Crystal structures of human ET B receptor provide mechanistic insight into receptor activation and partial activation. Nat Commun 2018; 9:4711. [PMID: 30413709 PMCID: PMC6226434 DOI: 10.1038/s41467-018-07094-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 10/14/2018] [Indexed: 12/16/2022] Open
Abstract
Endothelin receptors (ETA and ETB) are class A GPCRs activated by vasoactive peptide endothelins, and are involved in blood pressure regulation. ETB-selective signalling induces vasorelaxation, and thus selective ETB agonists are expected to be utilized for improved anti-tumour drug delivery and neuroprotection. Here, we report the crystal structures of human ETB receptor in complex with ETB-selective agonist, endothelin-3 and an ETB-selective endothelin analogue IRL1620. The structure of the endothelin-3-bound receptor reveals that the disruption of water-mediated interactions between W6.48 and D2.50 is critical for receptor activation, while these hydrogen-bonding interactions are partially preserved in the IRL1620-bound structure. Consistently, functional analysis reveals the partial agonistic effect of IRL1620. The current findings clarify the detailed molecular mechanism for the coupling between the orthosteric pocket and the G-protein binding, and the partial agonistic effect of IRL1620, thus paving the way for the design of improved agonistic drugs targeting ETB.
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Affiliation(s)
- Wataru Shihoya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, 113-0033, Japan
| | - Tamaki Izume
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, 113-0033, Japan
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Keitaro Yamashita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, 113-0033, Japan.,RIKEN SPring-8 Center, Hyogo, 679-5148, Japan
| | - Francois Marie Ngako Kadji
- Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | | | - Junken Aoki
- Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan.,Japan Agency for Medical Research and Development, Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, 100-0004, Japan
| | - Tomohiro Nishizawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, 113-0033, Japan.
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, 113-0033, Japan.
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5
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Dong F, Rues RB, Kazemi S, Dötsch V, Bernhard F. Molecular Determinants for Ligand Selectivity of the Cell-Free Synthesized Human Endothelin B Receptor. J Mol Biol 2018; 430:5105-5119. [PMID: 30342934 DOI: 10.1016/j.jmb.2018.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 10/02/2018] [Accepted: 10/12/2018] [Indexed: 01/14/2023]
Abstract
Extracellular domains of G-protein-coupled receptors act as initial molecular selectivity filters for subtype specific ligands and drugs. Chimeras of the human endothelin-B receptor containing structural units from the extracellular domains of the endothelin-A receptor were analyzed after their co-translational insertion into preformed nanodiscs. A short β-strand and a linker region in the second extracellular loop as well as parts of the extracellular N-terminal domain were identified as molecular discrimination sites for the endothelin-B receptor-selective agonists IRL1620, sarafotoxin 6c, 4Ala-ET-1 and ET-3, but not for the non-selective agonist ET-1 recognized by both endothelin receptors. A proposed second disulfide bridge in the endothelin-B receptor tethering the N-terminal domain with the third extracellular loop was not essential for ET-1 recognition and binding, but increased the receptor thermostability. We further demonstrate an experimental approach with cell-free synthesized engineered agonists to analyze the differential discrimination of peptide ligand topologies by the two endothelin receptors. The study is based on the engineering and cell-free insertion of G-protein-coupled receptors into defined membranes and may become interesting also for other targets as an alternative platform to reveal molecular details of ligand selectivity and ligand binding mechanisms.
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Affiliation(s)
- Fang Dong
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Ralf B Rues
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Sina Kazemi
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Frank Bernhard
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany.
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6
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Han SG, Ko S, Lee WK, Jung ST, Yu YG. Determination of the endothelin-1 recognition sites of endothelin receptor type A by the directed-degeneration method. Sci Rep 2017; 7:7577. [PMID: 28790412 PMCID: PMC5548930 DOI: 10.1038/s41598-017-08096-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 07/04/2017] [Indexed: 12/20/2022] Open
Abstract
G-protein coupled receptors (GPCRs) play indispensable physiological roles in cell proliferation, differentiation, and migration; therefore, identifying the mechanisms by which ligands bind to GPCRs is crucial for developing GPCR-targeting pharmaceutics and for understanding critical biological functions. Although some structural information is available regarding the interactions between GPCRs and their small molecule ligands, knowledge of how GPCRs interact with their corresponding macromolecule ligands, such as peptides and proteins, remains elusive. In this study, we have developed a novel strategy to investigate the precise ligand recognition mechanisms involved in the interaction of endothelin receptor type A (ETA) with its ligand, endothelin-1 (ET-1); we call this method “directed degeneration” method. Through flow cytometric screening of a randomized ETA library, statistical analysis of the identified sequences, and biochemical studies, the ligand interaction map was successfully obtained.
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Affiliation(s)
- Seong-Gu Han
- Department of Chemistry, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul, 136-702, Republic of Korea
| | - Sanghwan Ko
- Department of Chemistry, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul, 136-702, Republic of Korea
| | - Won-Kyu Lee
- Department of Chemistry, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul, 136-702, Republic of Korea.,New Drug Development Center, Osong Medical Innovation Foundation, Osong Sengmyung-Ro 123, Osong-eup, Heungdeok-gu, Cheongju-si, Chungbuk, Republic of Korea
| | - Sang Taek Jung
- Department of Chemistry, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul, 136-702, Republic of Korea.
| | - Yeon Gyu Yu
- Department of Chemistry, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul, 136-702, Republic of Korea.
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Shihoya W, Nishizawa T, Okuta A, Tani K, Dohmae N, Fujiyoshi Y, Nureki O, Doi T. Activation mechanism of endothelin ET B receptor by endothelin-1. Nature 2016; 537:363-368. [PMID: 27595334 DOI: 10.1038/nature19319] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 07/20/2016] [Indexed: 12/14/2022]
Abstract
Endothelin, a 21-amino-acid peptide, participates in various physiological processes, such as regulation of vascular tone, humoral homeostasis, neural crest cell development and neurotransmission. Endothelin and its G-protein-coupled receptor are involved in the development of various diseases, such as pulmonary arterial hypertension, and thus are important therapeutic targets. Here we report crystal structures of human endothelin type B receptor in the ligand-free form and in complex with the endogenous agonist endothelin-1. The structures and mutation analysis reveal the mechanism for the isopeptide selectivity between endothelin-1 and -3. Transmembrane helices 1, 2, 6 and 7 move and envelop the entire endothelin peptide, in a virtually irreversible manner. The agonist-induced conformational changes are propagated to the receptor core and the cytoplasmic G-protein coupling interface, and probably induce conformational flexibility in TM6. A comparison with the M2 muscarinic receptor suggests a shared mechanism for signal transduction in class A G-protein-coupled receptors.
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Affiliation(s)
- Wataru Shihoya
- Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan.,Cellular and Structural Physiology Institute, Nagoya University, Chikusa, Nagoya 464-8601, Japan.,Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0032, Japan
| | - Tomohiro Nishizawa
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0032, Japan.,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Akiko Okuta
- Cellular and Structural Physiology Institute, Nagoya University, Chikusa, Nagoya 464-8601, Japan
| | - Kazutoshi Tani
- Cellular and Structural Physiology Institute, Nagoya University, Chikusa, Nagoya 464-8601, Japan
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan
| | - Yoshinori Fujiyoshi
- Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan.,Cellular and Structural Physiology Institute, Nagoya University, Chikusa, Nagoya 464-8601, Japan
| | - Osamu Nureki
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0032, Japan
| | - Tomoko Doi
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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8
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Borrull A, Allard B, Wijkhuisen A, Herbet A, Lamourette P, Birouk W, Leiber D, Tanfin Z, Ducancel F, Boquet D, Couraud JY, Robin P. Rendomab B4, a monoclonal antibody that discriminates the human endothelin B receptor of melanoma cells and inhibits their migration. MAbs 2016; 8:1371-1385. [PMID: 27390909 DOI: 10.1080/19420862.2016.1208865] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Metastatic melanoma is an aggressive cancer with a poor prognostic, and the design of new targeted drugs to treat melanoma is a therapeutic challenge. A promising approach is to produce monoclonal antibodies (mAbs) against the endothelin B receptor (ETB), which is known to be overexpressed in melanoma and to contribute to proliferation, migration and vasculogenic mimicry associated with invasiveness of this cancer. We previously described rendomab-B1, a mAb produced by DNA immunization. It is endowed with remarkable characteristics in term of affinity, specificity and antagonist properties against human ETB expressed by the endothelial cells, but, surprisingly, had poor affinity for ETB expressed by melanoma cells. This characteristic strongly suggested the existence of a tumor-specific ETB form. In the study reported here, we identified a new mAb, rendomab-B4, which, in contrast to rendomab-B1, binds ETB expressed on UACC-257, WM-266-4 and SLM8 melanoma cells. Moreover, after binding to UACC-257 cells, rendomab-B4 is internalized and colocalizes with the endosomal protein EEA-1. Interestingly, rendomab-B4, despite its inability to compete with endothelin binding, is able to inhibit phospholipase C pathway and migration induced by endothelin. By contrast, rendomab-B4 fails to decrease ERK1/2 phosphorylation induced by endothelin, suggesting a biased effect on ETB. These particular properties make rendomab-B4 an interesting tool to analyze ETB-structure/function and a promising starting point for the development of new immunological tools in the field of melanoma therapeutics.
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Affiliation(s)
- Aurélie Borrull
- a CEA, iBiTec-S, SPI, Laboratoire d'Ingénierie des Anticorps pour la Santé , Gif-sur-Yvette , France.,b Université Paris Sud-11 , CNRS, UMR 8619, IBBMC , Orsay , France
| | - Bertrand Allard
- a CEA, iBiTec-S, SPI, Laboratoire d'Ingénierie des Anticorps pour la Santé , Gif-sur-Yvette , France
| | - Anne Wijkhuisen
- a CEA, iBiTec-S, SPI, Laboratoire d'Ingénierie des Anticorps pour la Santé , Gif-sur-Yvette , France.,c Université Paris Diderot, Sorbonne Paris Cité , Gif-sur-Yvette , France
| | - Amaury Herbet
- a CEA, iBiTec-S, SPI, Laboratoire d'Ingénierie des Anticorps pour la Santé , Gif-sur-Yvette , France
| | - Patricia Lamourette
- d CEA, iBiTec-S, SPI, Laboratoire d'Etude et de Recherche en Immunoanalyse , Gif-sur-Yvette , France
| | - Wided Birouk
- b Université Paris Sud-11 , CNRS, UMR 8619, IBBMC , Orsay , France
| | - Denis Leiber
- b Université Paris Sud-11 , CNRS, UMR 8619, IBBMC , Orsay , France
| | - Zahra Tanfin
- b Université Paris Sud-11 , CNRS, UMR 8619, IBBMC , Orsay , France
| | - Frédéric Ducancel
- a CEA, iBiTec-S, SPI, Laboratoire d'Ingénierie des Anticorps pour la Santé , Gif-sur-Yvette , France
| | - Didier Boquet
- a CEA, iBiTec-S, SPI, Laboratoire d'Ingénierie des Anticorps pour la Santé , Gif-sur-Yvette , France
| | - Jean-Yves Couraud
- a CEA, iBiTec-S, SPI, Laboratoire d'Ingénierie des Anticorps pour la Santé , Gif-sur-Yvette , France.,c Université Paris Diderot, Sorbonne Paris Cité , Gif-sur-Yvette , France
| | - Philippe Robin
- b Université Paris Sud-11 , CNRS, UMR 8619, IBBMC , Orsay , France
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Endothelin-1: Biosynthesis, Signaling and Vasoreactivity. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 77:143-75. [PMID: 27451097 DOI: 10.1016/bs.apha.2016.05.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Endothelin-1 (ET-1) is an extremely potent vasoconstrictor peptide originally isolated from endothelial cells. Its synthesis, mainly regulated at the gene transcription level, involves processing of a precursor by a furin-type proprotein convertase to an inactive intermediate, big ET-1. The latter peptide can then be cleaved directly by an endothelin-converting enzyme (ECE) into ET-1 or reach the active metabolite through a two-step process involving chymase hydrolyzing big ET-1 to ET-1 (1-31), itself needing conversion to ET-1 by neprilysin (NEP) to exert physiological activity. ET-1 signals through two G protein-coupled receptors, endothelin receptor A (ETA) and endothelin receptor B (ETB). Both receptors induce an increase in intracellular Ca(2+), mainly from the extracellular space through voltage-independent mechanisms, the receptor-operated channels and store-operated channels. ET-1 also induces signaling through epidermal growth factor receptor transactivation, oxidative stress induction, rho-kinase, and the activation (ETA) or inhibition (ETB) of the adenylate cyclase/cyclic adenosine monophosphate pathway. Arterial vasoconstriction is mediated mainly by the ETA receptor. ET-1, via endothelium-located ETB, relaxes arteries or constricts vessels following activation of the same receptor type on the smooth muscle, where it can interact with ETA. In addition, ETB-dependent vasoconstriction seems more prominent in the venous vasculature. A better understanding of how ET-1 is synthesized and how ETA and ETB receptors interact could help design better pharmacological agents in the treatment of cardiovascular diseases where targeting the ET-1 system is indicated.
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Gatfield J, Mueller Grandjean C, Bur D, Bolli MH, Nayler O. Distinct ETA receptor binding mode of macitentan as determined by site directed mutagenesis. PLoS One 2014; 9:e107809. [PMID: 25226600 PMCID: PMC4166607 DOI: 10.1371/journal.pone.0107809] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 08/23/2014] [Indexed: 11/29/2022] Open
Abstract
The competitive endothelin receptor antagonists (ERA) bosentan and ambrisentan, which have long been approved for the treatment of pulmonary arterial hypertension, are characterized by very short (1 min) occupancy half-lives at the ETA receptor. The novel ERA macitentan, displays a 20-fold increased receptor occupancy half-life, causing insurmountable antagonism of ET-1-induced signaling in pulmonary arterial smooth muscle cells. We show here that the slow ETA receptor dissociation rate of macitentan was shared with a set of structural analogs, whereas compounds structurally related to bosentan displayed fast dissociation kinetics. NMR analysis showed that macitentan adopts a compact structure in aqueous solution and molecular modeling suggests that this conformation tightly fits into a well-defined ETA receptor binding pocket. In contrast the structurally different and negatively charged bosentan-type molecules only partially filled this pocket and expanded into an extended endothelin binding site. To further investigate these different ETA receptor-antagonist interaction modes, we performed functional studies using ETA receptor variants harboring amino acid point mutations in the presumed ERA interaction site. Three ETA receptor residues significantly and differentially affected ERA activity: Mutation R326Q did not affect the antagonist activity of macitentan, however the potencies of bosentan and ambrisentan were significantly reduced; mutation L322A rendered macitentan less potent, whereas bosentan and ambrisentan were unaffected; mutation I355A significantly reduced bosentan potency, but not ambrisentan and macitentan potencies. This suggests that – in contrast to bosentan and ambrisentan - macitentan-ETA receptor binding is not dependent on strong charge-charge interactions, but depends predominantly on hydrophobic interactions. This different binding mode could be the reason for macitentan's sustained target occupancy and insurmountable antagonism.
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Affiliation(s)
- John Gatfield
- Actelion Pharmaceuticals Ltd., Allschwil, Switzerland
- * E-mail:
| | | | - Daniel Bur
- Actelion Pharmaceuticals Ltd., Allschwil, Switzerland
| | | | - Oliver Nayler
- Actelion Pharmaceuticals Ltd., Allschwil, Switzerland
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11
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Allard B, Wijkhuisen A, Borrull A, Deshayes F, Priam F, Lamourette P, Ducancel F, Boquet D, Couraud JY. Generation and characterization of rendomab-B1, a monoclonal antibody displaying potent and specific antagonism of the human endothelin B receptor. MAbs 2012; 5:56-69. [PMID: 23221682 DOI: 10.4161/mabs.22696] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Endothelin B receptor (ETBR) is a G protein-coupled receptor able to bind equally to the three identified human endothelin peptides. It is expressed primarily on vascular endothelial cells and involved in various physiological processes including vascular tone homeostasis, enteric nervous system development, melanogenesis and angiogenesis. Furthermore, overactivation or overexpression of ETBR have been associated with the development of various diseases such as cardiovascular disorders and cancers. Therefore, ETBR appears to be relevant target for the therapy or diagnosis of highly prevalent human diseases. In this study, we report the in vitro characterization of rendomab-B1, a monoclonal antibody (mAb) obtained by genetic immunization, which selectively recognizes the native form of human ETBR (hETBR). Rendomab-B1 is the first-reported mAb that behaves as a potent antagonist of hETBR. It recognizes an original extracellular conformational epitope on the receptor, distinct from the endothelin-1 (ET-1) binding site. Rendomab-B1 not only blocks ET-1-induced calcium signaling pathway and triggers rapid receptor internalization on recombinant hETBR-expressing cells, but also exerts pharmacological activities on human vascular endothelial cells, reducing both cell viability and ET-1-induced hETBR synthesis. In addition, binding experiments using rendomab-B1 on different melanoma cell lines reveal the structural and functional heterogeneity of hETBR expressed at the surface of these cancer cells, strongly suggesting the existence of tumor-specific receptors. Collectively, our results underscore the value of rendomab-B1 for research, therapeutic and diagnostic applications dealing with hETBR.
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Affiliation(s)
- Bertrand Allard
- CEA, iBiTecS, SPI, Laboratoire d'Ingénierie des Anticorps pour Santé, Gif sur Yvette, France
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12
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Compeer MG, Meens MJPMT, Hackeng TM, Neugebauer WA, Höltke C, De Mey JGR. Agonist-dependent modulation of arterial endothelinA receptor function. Br J Pharmacol 2012; 166:1833-45. [PMID: 22324472 DOI: 10.1111/j.1476-5381.2012.01896.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Endothelin-1 (ET-1) causes long-lasting vasoconstrictions. These can be prevented by ET(A) receptor antagonists but are only poorly reversed by these drugs. We tested the hypothesis that endothelin ET(A) receptors are susceptible to allosteric modulation by endogenous agonists and exogenous ligands. EXPERIMENTAL APPROACH Rat isolated mesenteric resistance arteries were pretreated with capsaicin and studied in wire myographs, in the presence of L-NAME and indomethacin to concentrate on arterial smooth muscle responses. KEY RESULTS Endothelins caused contractions with equal maximum but differing potency (ET-1 = ET-2 > ET-3). ET-1(1-15) neither mimicked nor antagonized these effects in the absence and presence of ET(16-21). 4(Ala) ET-1 (ET(B) agonist) and BQ788 (ET(B) antagonist) were without effects. BQ123 (peptide ET(A) antagonist) reduced the sensitivity and relaxed the contractile responses to endothelins. Both effects depended on the agonist (pK(B): ET-3 = ET-1 > ET-2; % relaxation: ET-3 = ET-2 > ET-1). Also, with PD156707 (non-peptide ET(A) antagonist) agonist-dependence and a discrepancy between preventive and inhibitory effects were observed. The latter was even more marked with bulky analogues of BQ123 and PD156707. CONCLUSIONS AND IMPLICATIONS These findings indicate allosteric modulation of arterial smooth muscle ET(A) receptor function by endogenous agonists and by exogenous endothelin receptor antagonists. This may have consequences for the diagnosis and pharmacotherapy of diseases involving endothelins.
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Affiliation(s)
- M G Compeer
- Department of Pharmacology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands
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Compeer MG, Suylen DP, Hackeng TM, De Mey JG. Endothelin-1 and -2: Two amino acids matter. Life Sci 2012; 91:607-12. [DOI: 10.1016/j.lfs.2012.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 02/10/2012] [Accepted: 02/13/2012] [Indexed: 11/29/2022]
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Pharmacological and structural characterization of long-sarafotoxins, a new family of endothelin-like peptides: Role of the C-terminus extension. Biochimie 2011; 94:461-70. [PMID: 21889567 DOI: 10.1016/j.biochi.2011.08.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 08/23/2011] [Indexed: 11/20/2022]
Abstract
Long-sarafotoxins (l-SRTXs) have recently been identified in both the venom of Atractaspis microlepidota and that of Atractaspis irregularis. They are characterized by different C-terminus extensions that follow the invariant Trp21, which plays a crucial role in endothelin-receptor binding. We initially determined the toxicity and three-dimensional structures of two chemically synthesized l-SRTXs that have different C-terminus extensions, namely SRTX-m (24 aa, including extension "D-E-P") and SRTX-i3 (25 aa, including extension "V-N-R-N"). Both peptides were shown to be highly toxic in mice and displayed the cysteine-stabilized α-helical motif that characterizes endothelins and short-SRTXs, to which a longer C-terminus with variable flexibility is added. To discern the functional and pharmacological consequences of the supplementary amino acids, different chimerical as well as truncated forms of SRTX were designed and synthesized. Thus, we either removed the extra-C-terminal residues of SRTX-m or i3, or grafted the latter onto the C-terminal extremity of a short-SRTX (s-SRTX) (ie. SRTX-b). Our competitive binding assays where SRTXs competed for iodinated endothelin-1 binding to cloned ET(A) and ET(B) receptor subtypes over-expressed in CHO cells, revealed the essential role of the C-terminus extensions for ET-receptor recognition. Indeed, l-SRTXs displayed an affinity three to four orders of magnitude lower as compared to SRTX-b for the two receptor subtypes. Moreover, grafting the C-terminus extension to SRTX-b induced a drastic decrease in affinity, while its removal (truncated l-SRTXs) yielded an affinity for ET-receptors similar to that of s-SRTXs. Furthermore, we established by intracellular Ca(2+) measurements that l-SRTXs, as well as s-SRTXs, display agonistic activities. We thus confirmed in these functional assays the major difference in potency for these two SRTX families as well as the crucial role of the C-terminus extension in their various pharmacological profiles. Finally, one of the chimeric toxin synthesized in this study appears to be one of the most potent and selective ligand of the ET(B) receptor known to date.
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Allard B, Priam F, Deshayes F, Ducancel F, Boquet D, Wijkhuisen A, Couraud JY. Electroporation-aided DNA immunization generates polyclonal antibodies against the native conformation of human endothelin B receptor. DNA Cell Biol 2011; 30:727-37. [PMID: 21688998 DOI: 10.1089/dna.2011.1239] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Endothelin B receptor (ET(B)R) is a G protein-coupled receptor (GPCR) specific for endothelin peptides (including endothelin-1, ET1), which mediates a variety of key physiological functions in normal tissues, such as modulation of vasomotor tone, tissue differentiation, or cell proliferation. Moreover, ET(B)R, overexpressed in various cancer cells including melanoma, has been implicated in the growth and progression of tumors, as well as in controlling T cell homing to tumors. To gather information on receptor structure and function, antibodies are generally considered choice molecular probes, but generation of such reagents against the native conformation of GPCRs is a real technical challenge. Here, we show that electroporation-aided genetic immunization, coupled to cardiotoxin pretreatment, is a simple and very efficient method to raise large amounts of polyclonal antibodies highly specific for native human ET(B)R (hET(B)R), as assessed by both flow cytometry analysis of different stably transfected cell lines and a new and rapid cell-based enzyme-linked immunosorbent assay that we also describe. The antibodies recognized two major epitopes on hET(B)R, mapped within the N-terminal extracellular domain. They were used to reveal hET(B)R on membranes of three different human melanoma cell lines, by flow cytometry and confocal microscopy, a method that we show is more relevant than mRNA polymerase chain reaction in assessing receptor expression. In addition, ET-1 partially competed with antibodies for receptor binding. The strategy described here, thus, efficiently generated new immunological tools to further analyze the role of ET(B)R under both normal and pathological conditions, including cancers. Above all, it can now be used to raise monoclonal antibodies against hET(B)R and, more generally, against GPCRs that constitute, by far, the largest reservoir of potential pharmacological targets.
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Affiliation(s)
- Bertrand Allard
- CEA, iBiTecS, SPI, Laboratoire d'Ingénierie des Anticorps pour la Santé (LIAS), Gif sur Yvette, France
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De Mey JG, Compeer MG, Lemkens P, Meens MJ. ETA-receptor antagonists or allosteric modulators? Trends Pharmacol Sci 2011; 32:345-51. [DOI: 10.1016/j.tips.2011.02.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 02/27/2011] [Accepted: 02/28/2011] [Indexed: 01/14/2023]
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Lättig J, Krause G. [Causes of selectivity, activation and inhibition. Molecular mechanisms of endothelin-receptor recognition]. PHARMAZIE IN UNSERER ZEIT 2010; 39:442-447. [PMID: 20967932 DOI: 10.1002/pauz.201000389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- Jens Lättig
- Leibniz-Institut für Molekulare Pharmakologie, Campus Berlin-Buch, Berlin
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Hiramatsu H, Aduma H, Tanaka Y, Miura T, Takeuchi H. Role of His16 in the structural flexibility of the C-terminal region of human endothelin-1. J Mol Struct 2010. [DOI: 10.1016/j.molstruc.2010.03.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Meens MJPMT, Compeer MG, Hackeng TM, van Zandvoort MA, Janssen BJA, De Mey JGR. Stimuli of sensory-motor nerves terminate arterial contractile effects of endothelin-1 by CGRP and dissociation of ET-1/ET(A)-receptor complexes. PLoS One 2010; 5:e10917. [PMID: 20532232 PMCID: PMC2879375 DOI: 10.1371/journal.pone.0010917] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 04/30/2010] [Indexed: 01/08/2023] Open
Abstract
Background Endothelin-1 (ET-1), a long-acting paracrine mediator, is implicated in cardiovascular diseases but clinical trials with ET-receptor antagonists were not successful in some areas. We tested whether the quasi-irreversible receptor-binding of ET-1 (i) limits reversing effects of the antagonists and (ii) can be selectively dissociated by an endogenous counterbalancing mechanism. Methodology/Principal findings In isolated rat mesenteric resistance arteries, ETA-antagonists, endothelium-derived relaxing factors and synthetic vasodilators transiently reduced contractile effects of ET-1 but did not prevent persistent effects of the peptide. Stimuli of peri-vascular vasodilator sensory-motor nerves such as capsaicin not only reduced but also terminated long-lasting effects of ET-1. This was prevented by CGRP-receptor antagonists and was mimicked by exogenous calcitonin gene-related peptide (CGRP). Using 2-photon laser scanning microscopy in vital intact arteries, capsaicin and CGRP, but not ETA-antagonism, were observed to promote dissociation of pre-existing ET-1/ETA-receptor complexes. Conclusions Irreversible binding and activation of ETA-receptors by ET-1 (i) occur at an antagonist-insensitive site of the receptor and (ii) are selectively terminated by endogenously released CGRP. Hence, natural stimuli of sensory-motor nerves that stimulate release of endogenous CGRP can be considered for therapy of diseases involving ET-1.
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Affiliation(s)
- Merlijn J. P. M. T. Meens
- Department of Pharmacology and Toxicology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Matthijs G. Compeer
- Department of Pharmacology and Toxicology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Tilman M. Hackeng
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Marc A. van Zandvoort
- Department of Biomedical Technology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Ben J. A. Janssen
- Department of Pharmacology and Toxicology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Jo G. R. De Mey
- Department of Pharmacology and Toxicology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
- * E-mail:
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Watts SW. Endothelin receptors: what's new and what do we need to know? Am J Physiol Regul Integr Comp Physiol 2009; 298:R254-60. [PMID: 19907001 DOI: 10.1152/ajpregu.00584.2009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Receptors are at the heart of how a molecule transmits a signal to a cell. Two receptor classes for endothelin (ET) are recognized, the ET(A) and ET(B) receptors. Intriguing questions have arisen in the field of ET receptor pharmacology, physiology, and function. For example, a host of pharmacological studies support the interaction of the ET(A) and ET(B) receptor in tissues (veins, arteries, bronchus, arterioles, esophagus), but yet few have been able to demonstrate direct ET(A)/ET(B) receptor interaction. Have we modeled this interaction wrong? Do we have a truly selective ET(A) receptor agonist such that we could selectively stimulate this important receptor? What can we learn from the recent phylogenic studies of the ET receptor family? Have we adequately addressed the number of biological molecules with which ET can interact to exert a biological effect? Recent mass spectrometry studies in our laboratory suggest that ET-1 interacts with other hereto unrecognized proteins. Biased ligands (ligands at the same receptor that elicit distinct signaling responses) have been discovered for other receptors. Do these exist for ET receptors and can we take advantage of this possibility in drug design? These and other questions will be posed in this minireview on topics on ET receptors.
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Affiliation(s)
- Stephanie W Watts
- Dept. of Pharmacology and Toxicology, B445 Life Sciences Bldg., East Lansing, MI 48824-1317, USA.
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Comparative sequence and structural analyses of G-protein-coupled receptor crystal structures and implications for molecular models. PLoS One 2009; 4:e7011. [PMID: 19756152 PMCID: PMC2738427 DOI: 10.1371/journal.pone.0007011] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Accepted: 08/10/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Up until recently the only available experimental (high resolution) structure of a G-protein-coupled receptor (GPCR) was that of bovine rhodopsin. In the past few years the determination of GPCR structures has accelerated with three new receptors, as well as squid rhodopsin, being successfully crystallized. All share a common molecular architecture of seven transmembrane helices and can therefore serve as templates for building molecular models of homologous GPCRs. However, despite the common general architecture of these structures key differences do exist between them. The choice of which experimental GPCR structure(s) to use for building a comparative model of a particular GPCR is unclear and without detailed structural and sequence analyses, could be arbitrary. The aim of this study is therefore to perform a systematic and detailed analysis of sequence-structure relationships of known GPCR structures. METHODOLOGY We analyzed in detail conserved and unique sequence motifs and structural features in experimentally-determined GPCR structures. Deeper insight into specific and important structural features of GPCRs as well as valuable information for template selection has been gained. Using key features a workflow has been formulated for identifying the most appropriate template(s) for building homology models of GPCRs of unknown structure. This workflow was applied to a set of 14 human family A GPCRs suggesting for each the most appropriate template(s) for building a comparative molecular model. CONCLUSIONS The available crystal structures represent only a subset of all possible structural variation in family A GPCRs. Some GPCRs have structural features that are distributed over different crystal structures or which are not present in the templates suggesting that homology models should be built using multiple templates. This study provides a systematic analysis of GPCR crystal structures and a consistent method for identifying suitable templates for GPCR homology modelling that will help to produce more reliable three-dimensional models.
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