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Kalaba P, Sanchez de la Rosa C, Möller A, Alewood PF, Muttenthaler M. Targeting the Oxytocin Receptor for Breast Cancer Management: A Niche for Peptide Tracers. J Med Chem 2024; 67:1625-1640. [PMID: 38235665 PMCID: PMC10859963 DOI: 10.1021/acs.jmedchem.3c01089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 12/07/2023] [Accepted: 12/20/2023] [Indexed: 01/19/2024]
Abstract
Breast cancer is a leading cause of death in women, and its management highly depends on early disease diagnosis and monitoring. This remains challenging due to breast cancer's heterogeneity and a scarcity of specific biomarkers that could predict responses to therapy and enable personalized treatment. This Perspective describes the diagnostic landscape for breast cancer management, molecular strategies targeting receptors overexpressed in tumors, the theranostic potential of the oxytocin receptor (OTR) as an emerging breast cancer target, and the development of OTR-specific optical and nuclear tracers to study, visualize, and treat tumors. A special focus is on the chemistry and pharmacology underpinning OTR tracer development, preclinical in vitro and in vivo studies, challenges, and future directions. The use of peptide-based tracers targeting upregulated receptors in cancer is a highly promising strategy complementing current diagnostics and therapies and providing new opportunities to improve cancer management and patient survival.
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Affiliation(s)
- Predrag Kalaba
- Institute
of Biological Chemistry, Faculty of Chemistry, University of Vienna, 1090 Vienna, Austria
| | | | - Andreas Möller
- QIMR
Berghofer Medical Research Institute, Brisbane, Queensland 4006, Australia
- The
Chinese University of Hong Kong, Hong Kong SAR 999077, China
| | - Paul F. Alewood
- Institute
for Molecular Bioscience, The University
of Queensland, Brisbane, Queensland 4072, Australia
| | - Markus Muttenthaler
- Institute
of Biological Chemistry, Faculty of Chemistry, University of Vienna, 1090 Vienna, Austria
- Institute
for Molecular Bioscience, The University
of Queensland, Brisbane, Queensland 4072, Australia
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2
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Lymperi S, Neofytou E, Vaitsopoulou C, Bazioti MG, Kalyvianaki K, Chatzimeletiou K, Lambropoulos A, Tarlatzi TB, Kampa M, Kolibianakis EM, Tarlatzis BC. Oxytocin preprotein and oxytocin receptor mRNA expression is altered in semen samples with abnormal semen parameters. Reprod Biomed Online 2023; 46:363-370. [PMID: 36604213 DOI: 10.1016/j.rbmo.2022.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 10/02/2022] [Accepted: 10/24/2022] [Indexed: 11/07/2022]
Abstract
RESEARCH QUESTION Are oxytocin preprotein and the oxytocin receptor expressed in human spermatozoa and is their mRNA expression different between normal semen samples and samples with at least one abnormal parameter? DESIGN An in-vitro prospective study of 175 semen samples from Greek men, according to World Health Organization criteria, 2010. mRNA expression levels were compared between different categories of semen samples, classified according to their concentration, total number, motility and morphology. Immunohistochemistry was used to detect oxytocin preprotein and its receptor on spermatozoa smears. RESULTS Compared with normal samples (normal motility and normal concentration), samples with at least one abnormal sperm parameter had statistically significantly lower oxytocin preprotein mRNA expression (P = 0.019) and higher oxytocin receptor mRNA expression levels (P < 0.001). Oligozoospermic samples had statistically significantly higher oxytocin preprotein mRNA expression levels (P = 0.002) and lower oxytocin receptor mRNA expression levels (P = 0.047). Asthenozoospermic samples had statistically significantly lower oxytocin preprotein mRNA expression levels (P < 0.001). Teratozoospermic samples had statistically significantly lower oxytocin preprotein mRNA expression levels (P = 0.049) and higher oxytocin receptor mRNA expression levels (P < 0.001). Oxytocin preprotein mRNA expression was positively associated with total progressive motility (P < 0.001) and negatively associated with the percentage of immotile spermatozoa (P = 0.001). Oxytocin receptor mRNA expression was negatively associated with the percentage of normal forms (P < 0.001). CONCLUSION Oxytocin preprotein and oxytocin receptor mRNA expression in spermatozoa could be used as a novel and unbiased diagnostic tool for male infertility.
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Affiliation(s)
- Stefania Lymperi
- Unit for Human Reproduction, 1st Department of Obstetrics and Gynecology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece; Private Diagnostic Laboratory Agias Sofias, Andrology Laboratory, Thessaloniki, Greece.
| | - Eirini Neofytou
- Unit for Human Reproduction, 1st Department of Obstetrics and Gynecology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Christine Vaitsopoulou
- Unit for Human Reproduction, 1st Department of Obstetrics and Gynecology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Maria-Georgia Bazioti
- Private Diagnostic Laboratory Agias Sofias, Andrology Laboratory, Thessaloniki, Greece
| | - Konstantina Kalyvianaki
- Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, Heraklion, GR-71003, Greece
| | - Katerina Chatzimeletiou
- Unit for Human Reproduction, 1st Department of Obstetrics and Gynecology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Alexandros Lambropoulos
- Laboratory of Molecular Biology, "Papageorgiou" General Hospital of Thessaloniki, Thessaloniki, Greece
| | - Theoni B Tarlatzi
- Unit for Human Reproduction, 1st Department of Obstetrics and Gynecology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Marilena Kampa
- Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, Heraklion, GR-71003, Greece
| | - Efstratios M Kolibianakis
- Unit for Human Reproduction, 1st Department of Obstetrics and Gynecology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Basil C Tarlatzis
- Unit for Human Reproduction, 1st Department of Obstetrics and Gynecology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
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3
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Carter CS, Kingsbury MA. Oxytocin and oxygen: the evolution of a solution to the ‘stress of life’. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210054. [PMID: 35856299 PMCID: PMC9272143 DOI: 10.1098/rstb.2021.0054] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Oxytocin (OT) and the OT receptor occupy essential roles in our current understanding of mammalian evolution, survival, sociality and reproduction. This narrative review examines the hypothesis that many functions attributed to OT can be traced back to conditions on early Earth, including challenges associated with managing life in the presence of oxygen and other basic elements, including sulfur. OT regulates oxidative stress and inflammation especially through effects on the mitochondria. A related nonapeptide, vasopressin, as well as molecules in the hypothalamic–pituitary–adrenal axis, including the corticotropin-releasing hormone family of molecules, have a broad set of functions that interact with OT. Interactions among these molecules have roles in the causes and consequence of social behaviour and the management of threat, fear and stress. Here, we discuss emerging evidence suggesting that unique properties of the OT system allowed vertebrates, and especially mammals, to manage over-reactivity to the ‘side effects’ of oxygen, including inflammation, oxidation and free radicals, while also supporting high levels of sociality and a perception of safety. This article is part of the theme issue ‘Interplays between oxytocin and other neuromodulators in shaping complex social behaviours’.
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Affiliation(s)
- C. Sue Carter
- Kinsey Institute, Indiana University, Bloomington, IN 47405, USA
- Department of Psychology, University of Virginia, Charlottesville, VA 22904, USA
| | - Marcy A. Kingsbury
- Lurie Center for Autism, Mass General Hospital for Children, Harvard University Medical School, Charlestown, Boston, MA 02129, USA
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4
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Bous J, Orcel H, Floquet N, Leyrat C, Lai-Kee-Him J, Gaibelet G, Ancelin A, Saint-Paul J, Trapani S, Louet M, Sounier R, Déméné H, Granier S, Bron P, Mouillac B. Cryo-electron microscopy structure of the antidiuretic hormone arginine-vasopressin V2 receptor signaling complex. SCIENCE ADVANCES 2021; 7:7/21/eabg5628. [PMID: 34020960 PMCID: PMC8139594 DOI: 10.1126/sciadv.abg5628] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 04/01/2021] [Indexed: 05/08/2023]
Abstract
The antidiuretic hormone arginine-vasopressin (AVP) forms a signaling complex with the V2 receptor (V2R) and the Gs protein, promoting kidney water reabsorption. Molecular mechanisms underlying activation of this critical G protein-coupled receptor (GPCR) signaling system are still unknown. To fill this gap of knowledge, we report here the cryo-electron microscopy structure of the AVP-V2R-Gs complex. Single-particle analysis revealed the presence of three different states. The two best maps were combined with computational and nuclear magnetic resonance spectroscopy constraints to reconstruct two structures of the ternary complex. These structures differ in AVP and Gs binding modes. They reveal an original receptor-Gs interface in which the Gαs subunit penetrates deep into the active V2R. The structures help to explain how V2R R137H or R137L/C variants can lead to two severe genetic diseases. Our study provides important structural insights into the function of this clinically relevant GPCR signaling complex.
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Affiliation(s)
- Julien Bous
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier cedex 5, France
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France
| | - Hélène Orcel
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier cedex 5, France
| | - Nicolas Floquet
- Institut des Biomolécules Max Mousseron, Université de Montpellier, CNRS, ENSCM, 34093 Montpellier cedex 5, France
| | - Cédric Leyrat
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier cedex 5, France
| | - Joséphine Lai-Kee-Him
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France
| | - Gérald Gaibelet
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier cedex 5, France
| | - Aurélie Ancelin
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France
| | - Julie Saint-Paul
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier cedex 5, France
| | - Stefano Trapani
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France
| | - Maxime Louet
- Institut des Biomolécules Max Mousseron, Université de Montpellier, CNRS, ENSCM, 34093 Montpellier cedex 5, France
| | - Rémy Sounier
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier cedex 5, France
| | - Hélène Déméné
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France
| | - Sébastien Granier
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier cedex 5, France.
| | - Patrick Bron
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, INSERM, 34090 Montpellier, France.
| | - Bernard Mouillac
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier cedex 5, France.
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5
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Molecular basis of ligand recognition and activation of human V2 vasopressin receptor. Cell Res 2021; 31:929-931. [PMID: 33742150 DOI: 10.1038/s41422-021-00480-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/25/2021] [Indexed: 11/08/2022] Open
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6
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McKay EC, Counts SE. Oxytocin Receptor Signaling in Vascular Function and Stroke. Front Neurosci 2020; 14:574499. [PMID: 33071746 PMCID: PMC7544744 DOI: 10.3389/fnins.2020.574499] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/31/2020] [Indexed: 12/13/2022] Open
Abstract
The oxytocin receptor (OXTR) is a G protein-coupled receptor with a diverse repertoire of intracellular signaling pathways, which are activated in response to binding oxytocin (OXT) and a similar nonapeptide, vasopressin. This review summarizes the cell and molecular biology of the OXTR and its downstream signaling cascades, particularly focusing on the vasoactive functions of OXTR signaling in humans and animal models, as well as the clinical applications of OXTR targeting cerebrovascular accidents.
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Affiliation(s)
- Erin C McKay
- Department of Translational Neuroscience, Michigan State University, Grand Rapids, MI, United States.,Neuroscience Program, Michigan State University, East Lansing, MI, United States
| | - Scott E Counts
- Department of Translational Neuroscience, Michigan State University, Grand Rapids, MI, United States.,Neuroscience Program, Michigan State University, East Lansing, MI, United States.,Department of Family Medicine, Michigan State University, Grand Rapids, MI, United States.,Hauenstein Neurosciences Center, Mercy Health Saint Mary's Hospital, Grand Rapids, MI, United States.,Michigan Alzheimer's Disease Research Center, Ann Arbor, MI, United States
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7
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Liu H, Gruber CW, Alewood PF, Möller A, Muttenthaler M. The oxytocin receptor signalling system and breast cancer: a critical review. Oncogene 2020; 39:5917-5932. [PMID: 32782397 PMCID: PMC7483001 DOI: 10.1038/s41388-020-01415-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/21/2020] [Accepted: 07/29/2020] [Indexed: 12/24/2022]
Abstract
Breast cancer is making up one-quarter of all new female cancer cases diagnosed worldwide. Breast cancer surgeries, radiation therapies, cytotoxic chemotherapies and targeted therapies have made significant progress and play a dominant role in breast cancer patient management. However, many challenges remain, including resistance to systemic therapies, tumour recurrence and metastasis. The cyclic neuropeptide oxytocin (OT) elicits a plethora of biological responses via the oxytocin receptor (OTR) in both the central and peripheral nervous system, including social bonding, stress, maternal behaviour, sexual activity, uterus contraction, milk ejection and cancer. As a typical member of the G protein-coupled receptor family, OTR represents also an intriguing target for cancer therapy. There is emerging evidence that OTR plays a role in breast cancer development and progression, and several breast cancer cell lines express OTR. However, despite supporting evidence that OT lowers breast cancer risks, its mechanistic role in breast cancer development and the related signalling pathways are not fully understood. Here, we review the current knowledge of the OT/OTR signalling system in healthy breast tissue as well as in breast cancer, and discuss OTR as a potential therapeutic target for breast cancer management.
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Affiliation(s)
- Huiping Liu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Christian W Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090, Vienna, Austria
| | - Paul F Alewood
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Andreas Möller
- Tumour Microenvironment Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia
| | - Markus Muttenthaler
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia. .,Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, 1090, Vienna, Austria.
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8
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Hilfiger L, Zhao Q, Kerspern D, Inquimbert P, Andry V, Goumon Y, Darbon P, Hibert M, Charlet A. A Nonpeptide Oxytocin Receptor Agonist for a Durable Relief of Inflammatory Pain. Sci Rep 2020; 10:3017. [PMID: 32080303 PMCID: PMC7033278 DOI: 10.1038/s41598-020-59929-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 02/02/2020] [Indexed: 02/01/2023] Open
Abstract
Oxytocin possesses several physiological and social functions, among which an important analgesic effect. For this purpose, oxytocin binds mainly to its unique receptor, both in the central nervous system and in the peripheral nociceptive terminal axon in the skin. However, despite its interesting analgesic properties and its current use in clinics to facilitate labor, oxytocin is not used in pain treatment. Indeed, it is rapidly metabolized, with a half-life in the blood circulation estimated at five minutes and in cerebrospinal fluid around twenty minutes in humans and rats. Moreover, oxytocin itself suffers from several additional drawbacks: a lack of specificity, an extremely poor oral absorption and distribution, and finally, a lack of patentability. Recently, a first non-peptide full agonist of oxytocin receptor (LIT-001) of low molecular weight has been synthesized with reported beneficial effect for social interactions after peripheral administration. In the present study, we report that a single intraperitoneal administration of LIT-001 in a rat model induces a long-lasting reduction in inflammatory pain-induced hyperalgesia symptoms, paving the way to an original drug development strategy for pain treatment.
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Affiliation(s)
- Louis Hilfiger
- Centre National de la Recherche Scientifique and University of Strasbourg, UPR3212 Institute of Cellular and Integrative Neurosciences, Strasbourg, France
| | - Qian Zhao
- Laboratoire d'Innovation Thérapeutique, Faculté de Pharmacie, UMR7200 CNRS/Université de Strasbourg, Illkirch, France
| | - Damien Kerspern
- Centre National de la Recherche Scientifique and University of Strasbourg, UPR3212 Institute of Cellular and Integrative Neurosciences, Strasbourg, France
| | - Perrine Inquimbert
- Centre National de la Recherche Scientifique and University of Strasbourg, UPR3212 Institute of Cellular and Integrative Neurosciences, Strasbourg, France
| | - Virginie Andry
- Centre National de la Recherche Scientifique and University of Strasbourg, UPR3212 Institute of Cellular and Integrative Neurosciences, Strasbourg, France
| | - Yannick Goumon
- Centre National de la Recherche Scientifique and University of Strasbourg, UPR3212 Institute of Cellular and Integrative Neurosciences, Strasbourg, France
| | - Pascal Darbon
- Centre National de la Recherche Scientifique and University of Strasbourg, UPR3212 Institute of Cellular and Integrative Neurosciences, Strasbourg, France
| | - Marcel Hibert
- Laboratoire d'Innovation Thérapeutique, Faculté de Pharmacie, UMR7200 CNRS/Université de Strasbourg, Illkirch, France
| | - Alexandre Charlet
- Centre National de la Recherche Scientifique and University of Strasbourg, UPR3212 Institute of Cellular and Integrative Neurosciences, Strasbourg, France.
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9
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10
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Scholz N, Langenhan T, Schöneberg T. Revisiting the classification of adhesion GPCRs. Ann N Y Acad Sci 2019; 1456:80-95. [PMID: 31365134 PMCID: PMC6900090 DOI: 10.1111/nyas.14192] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 05/19/2019] [Accepted: 06/20/2019] [Indexed: 12/13/2022]
Abstract
G protein–coupled receptors (GPCRs) are encoded by over 800 genes in the human genome. Motivated by different scientific rationales, the two classification systems that are mainly in use, the ABC and GRAFS systems, organize GPCRs according to their pharmacological features and phylogenetic relations, respectively. Within those systems, adhesion GPCRs (aGPCRs) constitute a group of over 30 mammalian homologs, most of which are still orphans with undefined activating signals and signal transduction properties. Previous efforts have further subdivided mammalian aGPCRs into nine subfamilies to indicate phylogenetic relationships. However, this subclassification scheme has shortcomings and inconsistencies that require attention. Here, we have reassessed the phylogenetic relationships of aGPCRs from vertebrate and invertebrate species. Our findings confirm that secretin receptor–like GPCRs most probably emerged from ancestral aGPCRs. We show that reassignment of several aGPCRs to families essentially requires input from functional data. Our analyses establish the need for introducing novel aGPCR subfamilies due to aGPCR sequences from invertebrate species that are not readily assignable to any existing subfamily. We conclude that the current classification systems ought to be updated to consider an unambiguous taxonomy of a hierarchically organized classification and pharmacological properties, and to accommodate phylogenetic affiliations between aGPCR genes within mammals and across the animal kingdom.
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Affiliation(s)
- Nicole Scholz
- Division of General Biochemistry, Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Tobias Langenhan
- Division of General Biochemistry, Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Torsten Schöneberg
- Division of Molecular Biochemistry, Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
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11
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Dayi A, Kiray M, Sisman A, Ozbal S, Baykara B, Aksu I, Uysal N. Dose dependent effects of oxytocin on cognitive defects and anxiety disorders in adult rats following acute infantile maternal deprivation stress. Biotech Histochem 2019; 94:469-480. [PMID: 31104534 DOI: 10.1080/10520295.2018.1528384] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Maternal deprivation at an early age is a powerful stressor that causes permanent alterations in cognitive and behavioral functions during the later stages of life. We investigated the effects of oxytocin on cognitive defects and anxiety disorders caused by acute infantile maternal deprivation in adult rats. We used 18-day-old Wistar albino rats of both sexes. The experimental groups included control (C), maternally deprived (MD), maternally deprived and treated with 0.02 μg/kg oxytocin (MD-0.02 µg/kg oxy), maternally deprived and treated with 2 μg/kg oxytocin (MD-2 µg/kg oxy). When the rats were 60 days old, the open field (OF) and elevated plus maze (EPM) behavioral tests, and the Morris water maze (MWM) test for spatial learning and memory were performed. In addition, the number of neurons in the hippocampus, prefrontal cortex (PFC) and amygdala were determined using quantitative histology. We also measured vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF) levels in the PFC. In both sexes, the MD group failed the learning test and the MD-2 μg/kg oxy group failed in the memory test. The MD-0.02 μg/kg oxy group spent more time in the open arm of the EPM device and their locomotor activities were greater in the OF test. The VEGF and BDNF levels in the PFC were higher in the MD-0.02 μg/kg oxy groups than the other maternally deprived groups (oxytocin ±). The number of PFC neurons was low in all male maternally deprived (oxytocin ±) groups, while the number of amygdala neurons was low in both female and male maternally deprived (oxytocin ±) groups. Male rats were more affected by maternal deprivation; administration of oxytocin had dose-dependent biphasic effects on learning, memory and anxiety.
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Affiliation(s)
- A Dayi
- Departments of Physiology, Dokuz Eylul University Medical School , Izmir , Turkey
| | - M Kiray
- Departments of Physiology, Dokuz Eylul University Medical School , Izmir , Turkey
| | - Ali Sisman
- Departments of Biochemistry, Dokuz Eylul University Medical School , Balcova , Turkey
| | - S Ozbal
- Departments of Histology and Embryology, Dokuz Eylul University Medical School , Izmir , Turkey
| | - B Baykara
- Departments of Histology and Embryology, Dokuz Eylul University Medical School , Izmir , Turkey
| | - I Aksu
- Departments of Physiology, Dokuz Eylul University Medical School , Izmir , Turkey
| | - N Uysal
- Departments of Physiology, Dokuz Eylul University Medical School , Izmir , Turkey
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12
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Pierce ML, Mehrotra S, Mustoe AC, French JA, Murray TF. A Comparison of the Ability of Leu 8- and Pro 8-Oxytocin to Regulate Intracellular Ca 2+ and Ca 2+-Activated K + Channels at Human and Marmoset Oxytocin Receptors. Mol Pharmacol 2019; 95:376-385. [PMID: 30739093 DOI: 10.1124/mol.118.114744] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/30/2019] [Indexed: 02/02/2023] Open
Abstract
The neurohypophyseal hormone oxytocin (OT) regulates biologic functions in both peripheral tissues and the central nervous system. In the central nervous system, OT influences social processes, including peer relationships, maternal-infant bonding, and affiliative social relationships. In mammals, the nonapeptide OT structure is highly conserved with leucine in the eighth position (Leu8-OT). In marmosets (Callithrix), a nonsynonymous nucleotide substitution in the OXT gene codes for proline in the eighth residue position (Pro8-OT). OT binds to its cognate G protein-coupled receptor (OTR) and exerts diverse effects, including stimulation (Gs) or inhibition (Gi/o) of adenylyl cyclase, stimulation of potassium channel currents (Gi), and activation of phospholipase C (Gq). Chinese hamster ovary cells expressing marmoset or human oxytocin receptors (mOTRs or hOTRs, respectively) were used to characterize OT signaling. At the mOTR, Pro8-OT was more efficacious than Leu8-OT in measures of Gq activation, with both peptides displaying subnanomolar potencies. At the hOTR, neither the potency nor efficacy of Pro8-OT and Leu8-OT differed with respect to Gq signaling. In both mOTR- and hOTR-expressing cells, Leu8-OT was more potent and modestly more efficacious than Pro8-OT in inducing hyperpolarization. In mOTR cells, Leu8-OT-induced hyperpolarization was modestly inhibited by pretreatment with pertussis toxin (PTX), consistent with a minor role for Gi/o activation; however, the Pro8-OT response in mOTR and hOTR cells was PTX insensitive. These findings are consistent with membrane hyperpolarization being largely mediated by a Gq signaling mechanism leading to Ca2+-dependent activation of K+ channels. Evaluation of the influence of apamin, charybdotoxin, paxilline, and TRAM-34 demonstrated involvement of both intermediate and large conductance Ca2+-activated K+ channels.
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Affiliation(s)
- Marsha L Pierce
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska (M.L.P., S.M., T.F.M.); and Department of Psychology, University of Nebraska, Omaha, Nebraska (A.C.M., J.A.F.)
| | - Suneet Mehrotra
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska (M.L.P., S.M., T.F.M.); and Department of Psychology, University of Nebraska, Omaha, Nebraska (A.C.M., J.A.F.)
| | - Aaryn C Mustoe
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska (M.L.P., S.M., T.F.M.); and Department of Psychology, University of Nebraska, Omaha, Nebraska (A.C.M., J.A.F.)
| | - Jeffrey A French
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska (M.L.P., S.M., T.F.M.); and Department of Psychology, University of Nebraska, Omaha, Nebraska (A.C.M., J.A.F.)
| | - Thomas F Murray
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska (M.L.P., S.M., T.F.M.); and Department of Psychology, University of Nebraska, Omaha, Nebraska (A.C.M., J.A.F.)
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Mustoe A, Taylor JH, French JA. Oxytocin structure and function in New World monkeys: from pharmacology to behavior. Integr Zool 2018; 13:634-654. [PMID: 29436774 PMCID: PMC6089668 DOI: 10.1111/1749-4877.12318] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Oxytocin (OT) is a hypothalamic nonapeptide that mediates a host of physiological and behavioral processes including reproductive physiology and social attachments. While the OT sequence structure is highly conserved among mammals, New World monkeys (NWMs) represent an unusual "hot spot" in OT structure variability among mammals. At least 6 distinct OT ligand variants among NWMs exist, yet it is currently unclear whether these evolved structural changes result in meaningful functional consequences. NWMs offer a new area to explore how these modifications to OT and its canonical G-protein coupled OT receptor (OTR) may mediate specific cellular, physiological and behavioral outcomes. In this review, we highlight relationships between OT ligand and OTR structural variability, specifically examining coevolution between OT ligands, OTRs, and physiological and behavioral phenotypes across NWMs. We consider whether these evolved modifications to the OT structure alter pharmacological profiles at human and marmoset OTRs, including changes to receptor binding, intracellular signaling and receptor internalization. Finally, we evaluate whether exogenous manipulation using OT variants in marmoset monkeys differentially enhance or impair behavioral processes involved in social relationships between pairmates, opposite-sex strangers, and parents and their offspring. Overall, it appears that changes to OT ligands in NWMs result in important changes ranging from cellular signaling to broad measures of social behavior.
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Affiliation(s)
- Aaryn Mustoe
- Program in Neuroscience and Behavior, University of Nebraska at Omaha, Omaha, Nebraska, USA
| | - Jack H Taylor
- Program in Neuroscience and Behavior, University of Nebraska at Omaha, Omaha, Nebraska, USA
| | - Jeffrey A French
- Program in Neuroscience and Behavior, University of Nebraska at Omaha, Omaha, Nebraska, USA
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14
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Ondrasek NR, Freeman SM, Bales KL, Calisi RM. Nonapeptide Receptor Distributions in Promising Avian Models for the Neuroecology of Flocking. Front Neurosci 2018; 12:713. [PMID: 30386202 PMCID: PMC6198083 DOI: 10.3389/fnins.2018.00713] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 09/19/2018] [Indexed: 12/16/2022] Open
Abstract
Collective behaviors, including flocking and group vocalizing, are readily observable across a diversity of free-living avian populations, yet we know little about how neural and ecological factors interactively regulate these behaviors. Because of their involvement in mediating a variety of social behaviors, including avian flocking, nonapeptides are likely mediators of collective behaviors. To advance the neuroecological study of collective behaviors in birds, we sought to map the neuroanatomical distributions of nonapeptide receptors in three promising avian models that are found across a diversity of environments and widely ranging ecological conditions: European starlings, house sparrows, and rock doves. We performed receptor autoradiography using the commercially available nonapeptide receptor radioligands, 125I-ornithine vasotocin analog and 125I-linear vasopressin antagonist, on brain tissue sections from wild-caught individuals from each species. Because there is known pharmacological cross-reactivity between nonapeptide receptor subtypes, we also performed a novel, competitive-binding experiment to examine the composition of receptor populations. We detected binding in numerous regions throughout the brains of each species, with several similarities and differences worth noting. Specifically, we report that all three species exhibit binding in the lateral septum, a key brain area known to regulate avian flocking. In addition, sparrows and starlings show dense binding in the dorsal arcopallium, an area that has received scant attention in the study of social grouping. Furthermore, our competitive binding results suggest that receptor populations in sparrows and starlings differ in the lateral septum versus the dorsal arcopallium. By providing the first comprehensive maps of nonapeptide receptors in European starlings, house sparrows, and rock doves, our work supports the future use of these species as avian models for neuroecological studies of collective behaviors in wild birds.
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Affiliation(s)
- Naomi R Ondrasek
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, United States
| | - Sara M Freeman
- Department of Psychology, University of California, Davis, Davis, CA, United States.,California National Primate Research Center, University of California, Davis, Davis, CA, United States
| | - Karen L Bales
- Department of Psychology, University of California, Davis, Davis, CA, United States.,California National Primate Research Center, University of California, Davis, Davis, CA, United States
| | - Rebecca M Calisi
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, United States
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15
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Muttenthaler M, Andersson Å, Vetter I, Menon R, Busnelli M, Ragnarsson L, Bergmayr C, Arrowsmith S, Deuis JR, Chiu HS, Palpant NJ, O'Brien M, Smith TJ, Wray S, Neumann ID, Gruber CW, Lewis RJ, Alewood PF. Subtle modifications to oxytocin produce ligands that retain potency and improved selectivity across species. Sci Signal 2017; 10:10/508/eaan3398. [PMID: 29208680 DOI: 10.1126/scisignal.aan3398] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Oxytocin and vasopressin mediate various physiological functions that are important for osmoregulation, reproduction, cardiovascular function, social behavior, memory, and learning through four G protein-coupled receptors that are also implicated in high-profile disorders. Targeting these receptors is challenging because of the difficulty in obtaining ligands that retain selectivity across rodents and humans for translational studies. We identified a selective and more stable oxytocin receptor (OTR) agonist by subtly modifying the pharmacophore framework of human oxytocin and vasopressin. [Se-Se]-oxytocin-OH displayed similar potency to oxytocin but improved selectivity for OTR, an effect that was retained in mice. Centrally infused [Se-Se]-oxytocin-OH potently reversed social fear in mice, confirming that this action was mediated by OTR and not by V1a or V1b vasopressin receptors. In addition, [Se-Se]-oxytocin-OH produced a more regular contraction pattern than did oxytocin in a preclinical labor induction and augmentation model using myometrial strips from cesarean sections. [Se-Se]-oxytocin-OH had no activity in human cardiomyocytes, indicating a potentially improved safety profile and therapeutic window compared to those of clinically used oxytocin. In conclusion, [Se-Se]-oxytocin-OH is a novel probe for validating OTR as a therapeutic target in various biological systems and is a promising new lead for therapeutic development. Our medicinal chemistry approach may also be applicable to other peptidergic signaling systems with similar selectivity issues.
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Affiliation(s)
- Markus Muttenthaler
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia. .,Faculty of Chemistry, Institute of Biological Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Åsa Andersson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.,School of Pharmacy, The University of Queensland, Brisbane, Queensland 4104, Australia
| | - Rohit Menon
- Department of Behavioral and Molecular Neurobiology, Regensburg Center of Neuroscience, University of Regensburg, 93053 Regensburg, Germany
| | - Marta Busnelli
- CNR-Institute of Neuroscience, 20129 Milan, Italy.,Department of Biotechnology and Translational Medicine, University of Milan, 20129 Milan, Italy
| | - Lotten Ragnarsson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Christian Bergmayr
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Sarah Arrowsmith
- Department of Cellular and Molecular Physiology, Harris-Wellbeing Preterm Birth Centre, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK
| | - Jennifer R Deuis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Han Sheng Chiu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Nathan J Palpant
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Margaret O'Brien
- National Centre for Biomedical Engineering Science, National University of Ireland, Galway H91 CF50, Ireland
| | - Terry J Smith
- National Centre for Biomedical Engineering Science, National University of Ireland, Galway H91 CF50, Ireland
| | - Susan Wray
- Department of Cellular and Molecular Physiology, Harris-Wellbeing Preterm Birth Centre, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK
| | - Inga D Neumann
- Department of Behavioral and Molecular Neurobiology, Regensburg Center of Neuroscience, University of Regensburg, 93053 Regensburg, Germany
| | - Christian W Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria.,School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Paul F Alewood
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.
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16
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Sabihi S, Dong SM, Maurer SD, Post C, Leuner B. Oxytocin in the medial prefrontal cortex attenuates anxiety: Anatomical and receptor specificity and mechanism of action. Neuropharmacology 2017; 125:1-12. [PMID: 28655609 DOI: 10.1016/j.neuropharm.2017.06.024] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 06/21/2017] [Accepted: 06/23/2017] [Indexed: 01/12/2023]
Abstract
Numerous studies in animals and humans have established that oxytocin (OT) reduces anxiety. In rats, the prelimbic (PL) subregion of the medial prefrontal cortex (mPFC) is among the brain areas implicated in the anxiolytic actions of OT. However, questions remain about the anatomical and receptor specificity of OT and its mechanism of action. Here we assessed whether the regulation of anxiety by mPFC OT is restricted to the PL subregion and evaluated whether oxytocin receptor (OTR) activation is required for OT to have an anxiolytic effect. We also examined whether OT interacts with GABA in the mPFC to reduce anxiety and investigated the extent to which OT in the mPFC affects activation of mPFC GABA neurons as well as neuronal activation in the amygdala, a primary target of the mPFC which is part of the neural network regulating anxiety. We found that OT reduced anxiety-like behavior when delivered to the PL, but not infralimbic or anterior cingulate subregions of the mPFC. The anxiolytic effect of OT in the PL mPFC was blocked by pretreatment with an OTR, but not a vasopressin receptor, antagonist as well as with a GABAA receptor antagonist. Lastly, administration of OT to the PL mPFC was accompanied by increased activation of GABA neurons in the PL mPFC and altered neuronal activation of the amygdala following anxiety testing. These results demonstrate that OT in the PL mPFC attenuates anxiety-related behavior and may do so by engaging GABAergic neurons which ultimately modulate downstream brain regions implicated in anxiety.
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Affiliation(s)
- Sara Sabihi
- The Ohio State University, Department of Psychology, Columbus, OH 43210, United States
| | - Shirley M Dong
- The Ohio State University, Department of Psychology, Columbus, OH 43210, United States
| | - Skyler D Maurer
- The Ohio State University, Department of Psychology, Columbus, OH 43210, United States
| | - Caitlin Post
- The Ohio State University, Department of Psychology, Columbus, OH 43210, United States
| | - Benedetta Leuner
- The Ohio State University, Department of Psychology, Columbus, OH 43210, United States; The Ohio State University, Department of Neuroscience, Columbus, OH 43210, United States; The Ohio State University, Behavioral Neuroendocrinology Group, Columbus, OH 43210, United States.
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17
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Francis SM, Kim SJ, Kistner-Griffin E, Guter S, Cook EH, Jacob S. ASD and Genetic Associations with Receptors for Oxytocin and Vasopressin- AVPR1A, AVPR1B, and OXTR. Front Neurosci 2016; 10:516. [PMID: 27920663 PMCID: PMC5118619 DOI: 10.3389/fnins.2016.00516] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 10/26/2016] [Indexed: 01/09/2023] Open
Abstract
Background: There are limited treatments available for autism spectrum disorder (ASD). Studies have reported significant associations between the receptor genes of oxytocin (OT) and vasopressin (AVP) and ASD diagnosis, as well as ASD-related phenotypes. Researchers have also found the manipulation of these systems affects social and repetitive behaviors, core characteristics of ASD. Consequently, research involving the oxytocin/vasopressin pathways as intervention targets has increased. Therefore, further examination into the relationship between these neuropeptides and ASD was undertaken. In this study, we examined associations between variants in the receptor genes of vasopressin (AVPR1A, AVPR1B), oxytocin (OXTR), and ASD diagnosis along with related subphenotypes. Methods: Probands were assessed using Autism Diagnostic Interview-Revised, Autism Diagnostic Observation Schedule, and clinical DSM-IV-TR criteria. Single nucleotide polymorphisms (SNPs) in AVPR1B and OXTR, and microsatellites in AVPR1A were genotyped in ~200 families with a proband with ASD. Family-based association testing (FBAT) was utilized to determine associations between variants and ASD. Haplotypes composed of OXTR SNPs (i.e., rs53576-rs2254298-rs2268493) were also analyzed due to previously published associations. Results: Using the additive inheritance model in FBAT we found associations between AVPR1B SNPs (rs28632197, p = 0.005, rs35369693, p = 0.025) and diagnosis. As in other studies, OXTR rs2268493 (p = 0.050) was associated with diagnosis. rs2268493 was also associated with ASD subphenotypes of social withdrawal (p = 0.013) and Insistence on Sameness (p = 0.039). Further analyses demonstrated that the haplotype, rs2254298–rs2268493 was found to be significantly associated with diagnosis (A-T; p = 0.026). FBAT was also used to analyze AVPR1A microsatellites (RS1 and RS3). Both length variants were found to be associated with restrictive, repetitive behaviors, but not overall diagnosis. Correction for multiple comparisons was performed for SNPs tested in each gene region, only AVPR1B SNPs remained significantly associated with ASD diagnosis. Conclusions: Autism is a heterogeneous disorder with many genes and pathways that contribute to its development. SNPs and microsatellites in the receptor genes of OT and AVP are associated with ASD diagnosis and measures of social behavior as well as restricted repetitive behaviors. We reported a novel association with ASD and AVPR1B SNPs. Understanding of genotype-phenotype relationships may be helpful in the development of pharmacological interventions for the OT/AVP system.
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Affiliation(s)
- Sunday M Francis
- Department of Psychiatry, University of Minnesota Minneapolis, MN, USA
| | - Soo-Jeong Kim
- Department of Psychiatry and Behavioral Sciences, University of Washington WA, USA
| | - Emily Kistner-Griffin
- Biostatistics Shared Resource, Hollings Cancer Center, Medical University of South Carolina Charleston, SC, USA
| | - Stephen Guter
- Department of Psychiatry, Institute of Juvenile Research, University of Illinois at Chicago Chicago, IL, USA
| | - Edwin H Cook
- Department of Psychiatry, Institute of Juvenile Research, University of Illinois at Chicago Chicago, IL, USA
| | - Suma Jacob
- Department of Psychiatry, University of Minnesota Minneapolis, MN, USA
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18
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French JA, Taylor JH, Mustoe AC, Cavanaugh J. Neuropeptide diversity and the regulation of social behavior in New World primates. Front Neuroendocrinol 2016; 42:18-39. [PMID: 27020799 PMCID: PMC5030117 DOI: 10.1016/j.yfrne.2016.03.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 02/27/2016] [Accepted: 03/24/2016] [Indexed: 01/09/2023]
Abstract
Oxytocin (OT) and vasopressin (AVP) are important hypothalamic neuropeptides that regulate peripheral physiology, and have emerged as important modulators of brain function, particularly in the social realm. OT structure and the genes that ultimately determine structure are highly conserved among diverse eutherian mammals, but recent discoveries have identified surprising variability in OT and peptide structure in New World monkeys (NWM), with five new OT variants identified to date. This review explores these new findings in light of comparative OT/AVP ligand evolution, documents coevolutionary changes in the oxytocin and vasopressin receptors (OTR and V1aR), and highlights the distribution of neuropeptidergic neurons and receptors in the primate brain. Finally, the behavioral consequences of OT and AVP in regulating NWM sociality are summarized, demonstrating important neuromodulatory effects of these compounds and OT ligand-specific influences in certain social domains.
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Affiliation(s)
- Jeffrey A French
- Program in Neuroscience and Behavior, University of Nebraska at Omaha, Omaha, NE 68182, USA.
| | - Jack H Taylor
- Program in Neuroscience and Behavior, University of Nebraska at Omaha, Omaha, NE 68182, USA
| | - Aaryn C Mustoe
- Program in Neuroscience and Behavior, University of Nebraska at Omaha, Omaha, NE 68182, USA
| | - Jon Cavanaugh
- Program in Neuroscience and Behavior, University of Nebraska at Omaha, Omaha, NE 68182, USA
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19
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Passoni I, Leonzino M, Gigliucci V, Chini B, Busnelli M. Carbetocin is a Functional Selective Gq Agonist That Does Not Promote Oxytocin Receptor Recycling After Inducing β-Arrestin-Independent Internalisation. J Neuroendocrinol 2016; 28. [PMID: 26751410 PMCID: PMC5021139 DOI: 10.1111/jne.12363] [Citation(s) in RCA: 22] [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: 11/06/2015] [Revised: 12/30/2015] [Accepted: 01/07/2016] [Indexed: 01/08/2023]
Abstract
Carbetocin, a long-acting oxytocin analogue, has been reported to elicit interesting and peculiar behavioural effects. The present study investigated the molecular pharmacology of carbetocin, aiming to better understand the molecular basis of its action in the brain. Using bioluminescence resonance energy transfer biosensors, we characterised the effects of carbetocin on the three human oxytocin/vasopressin receptors expressed in the nervous system: the oxytocin receptor (OXTR) and the vasopressin V1a (V1aR) and V1b (V1bR) receptors. Our results indicate that (i) carbetocin activates the OXTR but not the V1aR and V1bR at which it may act as an antagonist; (ii) carbetocin selectively activates only the OXTR/Gq pathway displaying a strong functional selectivity; (iii) carbetocin is a partial agonist at the OXTR/Gq coupling; (iv) carbetocin promotes OXTR internalisation via a previously unreported β-arrestin-independent pathway; and (v) carbetocin does not induce OXTR recycling to the plasma membrane. Altogether, these molecular pharmacology features identify carbetocin as a substantially different analogue compared to the endogenous oxytocin and, consequently, carbetocin is not expected to mimic oxytocin in the brain. Whether these unique features of carbetocin could be exploited therapeutically remains to be established.
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Affiliation(s)
- I Passoni
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - M Leonzino
- CNR, Institute of Neuroscience, Milan, Italy
| | - V Gigliucci
- CNR, Institute of Neuroscience, Milan, Italy
| | - B Chini
- CNR, Institute of Neuroscience, Milan, Italy
- Humanitas Clinical and Research Institute, Rozzano, Italy
| | - M Busnelli
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
- CNR, Institute of Neuroscience, Milan, Italy
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20
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Oxytocin and Social Adaptation: Insights from Neuroimaging Studies of Healthy and Clinical Populations. Trends Cogn Sci 2016; 20:133-145. [DOI: 10.1016/j.tics.2015.10.009] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/28/2015] [Accepted: 10/29/2015] [Indexed: 11/18/2022]
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21
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Iwakura H, Kangawa K, Nakao K. The regulation of circulating ghrelin - with recent updates from cell-based assays. Endocr J 2015; 62:107-22. [PMID: 25273611 DOI: 10.1507/endocrj.ej14-0419] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Ghrelin is a stomach-derived orexigenic hormone with a wide range of physiological functions. Elucidation of the regulation of the circulating ghrelin level would lead to a better understanding of appetite control in body energy homeostasis. Earlier studies revealed that circulating ghrelin levels are under the control of both acute and chronic energy status: at the acute scale, ghrelin levels are increased by fasting and decreased by feeding, whereas at the chronic scale, they are high in obese subjects and low in lean subjects. Subsequent studies revealed that nutrients, hormones, or neural activities can influence circulating ghrelin levels in vivo. Recently developed in vitro assay systems for ghrelin secretion can assess whether and how individual factors affect ghrelin secretion from cells. In this review, on the basis of numerous human, animal, and cell-based studies, we summarize current knowledge on the regulation of circulating ghrelin levels and enumerate the factors that influence ghrelin levels.
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Affiliation(s)
- Hiroshi Iwakura
- Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
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22
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Evolutionary pattern in the OXT-OXTR system in primates: coevolution and positive selection footprints. Proc Natl Acad Sci U S A 2014; 112:88-93. [PMID: 25535371 DOI: 10.1073/pnas.1419399112] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Oxytocin is a nonapeptide involved in a wide range of physiologic and behavioral functions. Until recently, it was believed that an unmodified oxytocin sequence was present in all placental mammals. This study analyzed oxytocin (OXT) in 29 primate species and the oxytocin receptor (OXTR) in 21 of these species. We report here three novel OXT forms in the New World monkeys, as well as a more extensive distribution of a previously described variant (Leu8Pro). In structural terms, these OXTs share the same three low-energy conformations in solution during molecular dynamic simulations, with subtle differences in their side chains. A consistent signal of positive selection was detected in the Cebidae family, and OXT position 8 showed a statistically significant (P = 0.013) correlation with litter size. Several OXTR changes were identified, some of them promoting gain or loss of putative phosphorylation sites, with possible consequences for receptor internalization and desensitization. OXTR amino acid sites are under positive selection, and intramolecular and intermolecular coevolutionary processes with OXT were also detected. We suggest that some New World monkey OXT-OXTR forms can be correlated to male parental care through the increase of cross-reactivity with its correlated vasopressin system.
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23
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Francis SM, Sagar A, Levin-Decanini T, Liu W, Carter CS, Jacob S. Oxytocin and vasopressin systems in genetic syndromes and neurodevelopmental disorders. Brain Res 2014; 1580:199-218. [PMID: 24462936 PMCID: PMC4305432 DOI: 10.1016/j.brainres.2014.01.021] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 11/08/2013] [Accepted: 01/15/2014] [Indexed: 10/25/2022]
Abstract
Oxytocin (OT) and arginine vasopressin (AVP) are two small, related neuropeptide hormones found in many mammalian species, including humans. Dysregulation of these neuropeptides have been associated with changes in behavior, especially social interactions. We review how the OT and AVP systems have been investigated in Autism Spectrum Disorder (ASD), Prader-Willi Syndrome (PWS), Williams Syndrome (WS) and Fragile X syndrome (FXS). All of these neurodevelopmental disorders (NDD) are marked by social deficits. While PWS, WS and FXS have identified genetic mutations, ASD stems from multiple genes with complex interactions. Animal models of NDD are invaluable for studying the role and relatedness of OT and AVP in the developing brain. We present data from a FXS mouse model affecting the fragile X mental retardation 1 (Fmr1) gene, resulting in decreased OT and AVP staining cells in some brain regions. Reviewing the research about OT and AVP in these NDD suggests that altered OT pathways may be downstream from different etiological factors and perturbations in development. This has implications for ongoing studies of the therapeutic application of OT in NDD. This article is part of a Special Issue entitled Oxytocin and Social Behav.
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Affiliation(s)
- S M Francis
- University of Minnesota, Department of Psychiatry, Minneapolis, MN, USA
| | - A Sagar
- University of California at Irvine, Department of Psychiatry and Human Behavior, USA
| | - T Levin-Decanini
- University of Minnesota, Department of Psychiatry, Minneapolis, MN, USA
| | - W Liu
- Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - C S Carter
- University of North Carolina, Department of Psychiatry, Chapel Hill, NC, USA
| | - S Jacob
- University of Minnesota, Department of Psychiatry, Minneapolis, MN, USA.
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24
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Oxytocin in the prelimbic medial prefrontal cortex reduces anxiety-like behavior in female and male rats. Psychoneuroendocrinology 2014; 45:31-42. [PMID: 24845174 PMCID: PMC4067951 DOI: 10.1016/j.psyneuen.2014.03.009] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 03/18/2014] [Accepted: 03/20/2014] [Indexed: 01/31/2023]
Abstract
The neuropeptide oxytocin (OT) is anxiolytic in rodents and humans. However, the specific brain regions where OT acts to regulate anxiety requires further investigation. The medial prefrontal cortex (mPFC) has been shown to play a role in the modulation of anxiety-related behavior. In addition, the mPFC contains OT-sensitive neurons, expresses OT receptors, and receives long range axonal projections from OT-producing neurons in the hypothalamus, suggesting that the mPFC may be a target where OT acts to diminish anxiety. To investigate this possibility, female rats were administered OT bilaterally into the prelimbic (PL) region of the mPFC and anxiety-like behavior assessed. In addition, to determine if the effects of OT on anxiety-like behavior are sex dependent and to evaluate the specificity of OT, male and female anxiety-like behavior was tested following delivery of either OT or the closely related neuropeptide arginine vasopressin (AVP) into the PL mPFC. Finally, the importance of endogenous OT in the regulation of anxiety-like behavior was examined in male and female rats that received PL infusions of an OT receptor antagonist (OTR-A). Overall, even though males and females showed some differences in their baseline levels of anxiety-like behavior, OT in the PL region of the mPFC decreased anxiety regardless of sex. In contrast, neither AVP nor an OTR-A affected anxiety-like behavior in males or females. Together, these findings suggest that although endogenous OT in the PL region of the mPFC does not influence anxiety, the PL mPFC is a site where exogenous OT may act to attenuate anxiety-related behavior independent of sex.
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25
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Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Spedding M, Peters JA, Harmar AJ. The Concise Guide to PHARMACOLOGY 2013/14: G protein-coupled receptors. Br J Pharmacol 2013; 170:1459-581. [PMID: 24517644 PMCID: PMC3892287 DOI: 10.1111/bph.12445] [Citation(s) in RCA: 505] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. G protein-coupled receptors are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates.
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Affiliation(s)
- Stephen PH Alexander
- School of Life Sciences, University of Nottingham Medical SchoolNottingham, NG7 2UH, UK
| | - Helen E Benson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Elena Faccenda
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Adam J Pawson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Joanna L Sharman
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | | | - John A Peters
- Neuroscience Division, Medical Education Institute, Ninewells Hospital and Medical School, University of DundeeDundee, DD1 9SY, UK
| | - Anthony J Harmar
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
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Oxytocic plant cyclotides as templates for peptide G protein-coupled receptor ligand design. Proc Natl Acad Sci U S A 2013; 110:21183-8. [PMID: 24248349 DOI: 10.1073/pnas.1311183110] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cyclotides are plant peptides comprising a circular backbone and three conserved disulfide bonds that confer them with exceptional stability. They were originally discovered in Oldenlandia affinis based on their use in traditional African medicine to accelerate labor. Recently, cyclotides have been identified in numerous plant species of the coffee, violet, cucurbit, pea, potato, and grass families. Their unique structural topology, high stability, and tolerance to sequence variation make them promising templates for the development of peptide-based pharmaceuticals. However, the mechanisms underlying their biological activities remain largely unknown; specifically, a receptor for a native cyclotide has not been reported hitherto. Using bioactivity-guided fractionation of an herbal peptide extract known to indigenous healers as "kalata-kalata," the cyclotide kalata B7 was found to induce strong contractility on human uterine smooth muscle cells. Radioligand displacement and second messenger-based reporter assays confirmed the oxytocin and vasopressin V1a receptors, members of the G protein-coupled receptor family, as molecular targets for this cyclotide. Furthermore, we show that cyclotides can serve as templates for the design of selective G protein-coupled receptor ligands by generating an oxytocin-like peptide with nanomolar affinity. This nonapeptide elicited dose-dependent contractions on human myometrium. These observations provide a proof of concept for the development of cyclotide-based peptide ligands.
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Yang Y, Li H, Ward R, Gao L, Wei JF, Xu TR. Novel oxytocin receptor agonists and antagonists: a patent review (2002 - 2013). Expert Opin Ther Pat 2013; 24:29-46. [PMID: 24094047 DOI: 10.1517/13543776.2014.845168] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Oxytocin is a nine amino acid cyclic peptide hormone with a high degree of uterotonic activity. The oxytocin receptor (Oxtr) is most strongly expressed in the uterus and mammary gland, but can also be found in regions of the brain, showing a neurotransmitter-like activity. The Oxtr knockout mice have no obvious defects in fertility or sexual behavior, but display aberrant social behavior. All of these suggest that Oxtr may become an important therapeutic target for the treatment of a wide range of conditions. AREAS COVERED This article will highlight the significant progress that has been made in the discovery and development of Oxtr agonists and antagonists in the patent literature between January 2002 and May 2013. EXPERT OPINION In the past decade, cumulative evidence supports the idea that activation of the Oxtr can have a positive effect upon human cognition and social behavior. The authors suggest that new agonists and antagonists may play an important role in the treatment of disorders such as anxiety, autism or schizophrenia. It may even be that older Oxtr agonists and antagonists, which were used to overcome labor-related dysfunction, may also have a significant impact on human social behavior.
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Affiliation(s)
- Yang Yang
- Kunming University of Science and Technology, Faculty of Life Science and Technology , Kunming, Yunnan 650500 , China +86 871 65911300 ; +86 871 65911300 ;
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Abstract
The design and development of selective ligands for the human OT (oxytocin) and AVP (arginine vasopressin) receptors is a big challenge since the different receptor subtypes and their native peptide ligands display great similarity. Detailed understanding of the mechanism of OT's interaction with its receptor is important and may assist in the ligand- or structure-based design of selective and potent ligands. In the present article, we compared 69 OT- and OT-like receptor sequences with regards to their molecular evolution and diversity, utilized an in silico approach to map the common ligand interaction sites of recently published G-protein-coupled receptor structures to a model of the human OTR (OT receptor) and compared these interacting residues within a selection of different OTR sequences. Our analysis suggests the existence of a binding site for OT peptides within the common transmembrane core region of the receptor, but it appears extremely difficult to identify receptor or ligand residues that could explain the selectivity of OT to its receptors. We remain confident that the presented evolutionary overview and modelling approach will aid interpretation of forthcoming OTR crystal structures.
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Kim J, Stirling KJ, Cooper ME, Ascoli M, Momany AM, McDonald EL, Ryckman KK, Rhea L, Schaa KL, Cosentino V, Gadow E, Saleme C, Shi M, Hallman M, Plunkett J, Teramo KA, Muglia LJ, Feenstra B, Geller F, Boyd HA, Melbye M, Marazita ML, Dagle JM, Murray JC. Sequence variants in oxytocin pathway genes and preterm birth: a candidate gene association study. BMC MEDICAL GENETICS 2013; 14:77. [PMID: 23889750 PMCID: PMC3737028 DOI: 10.1186/1471-2350-14-77] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 07/18/2013] [Indexed: 11/10/2022]
Abstract
Background Preterm birth (PTB) is a complex disorder associated with significant neonatal mortality and morbidity and long-term adverse health consequences. Multiple lines of evidence suggest that genetic factors play an important role in its etiology. This study was designed to identify genetic variation associated with PTB in oxytocin pathway genes whose role in parturition is well known. Methods To identify common genetic variants predisposing to PTB, we genotyped 16 single nucleotide polymorphisms (SNPs) in the oxytocin (OXT), oxytocin receptor (OXTR), and leucyl/cystinyl aminopeptidase (LNPEP) genes in 651 case infants from the U.S. and one or both of their parents. In addition, we examined the role of rare genetic variation in susceptibility to PTB by conducting direct sequence analysis of OXTR in 1394 cases and 1112 controls from the U.S., Argentina, Denmark, and Finland. This study was further extended to maternal triads (maternal grandparents-mother of a case infant, N=309). We also performed in vitro analysis of selected rare OXTR missense variants to evaluate their functional importance. Results Maternal genetic effect analysis of the SNP genotype data revealed four SNPs in LNPEP that show significant association with prematurity. In our case–control sequence analysis, we detected fourteen coding variants in exon 3 of OXTR, all but four of which were found in cases only. Of the fourteen variants, three were previously unreported novel rare variants. When the sequence data from the maternal triads were analyzed using the transmission disequilibrium test, two common missense SNPs (rs4686302 and rs237902) in OXTR showed suggestive association for three gestational age subgroups. In vitro functional assays showed a significant difference in ligand binding between wild-type and two mutant receptors. Conclusions Our study suggests an association between maternal common polymorphisms in LNPEP and susceptibility to PTB. Maternal OXTR missense SNPs rs4686302 and rs237902 may have gestational age-dependent effects on prematurity. Most of the OXTR rare variants identified do not appear to significantly contribute to the risk of PTB, but those shown to affect receptor function in our in vitro study warrant further investigation. Future studies with larger sample sizes are needed to confirm the findings of this study.
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Affiliation(s)
- Jinsil Kim
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
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Molecular evolution of the oxytocin–oxytocin receptor system in eutherians. Mol Phylogenet Evol 2013; 67:520-8. [DOI: 10.1016/j.ympev.2013.02.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Revised: 01/24/2013] [Accepted: 02/15/2013] [Indexed: 11/23/2022]
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31
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Exploring bioactive peptides from natural sources for oxytocin and vasopressin drug discovery. Future Med Chem 2013; 4:1791-8. [PMID: 23043476 DOI: 10.4155/fmc.12.108] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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Slusarz MJ, Sikorska E, Slusarz R. Interactions of vasopressin and oxytocin receptors with vasopressin analogues substituted in position 2 with 3,3'-diphenylalanine--a molecular docking study. J Pept Sci 2013; 19:118-26. [PMID: 23303737 DOI: 10.1002/psc.2485] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 12/12/2012] [Accepted: 12/20/2012] [Indexed: 11/11/2022]
Abstract
Vasopressin and oxytocin receptors belong to the superfamily of G protein-coupled receptors and play an important role in many physiological functions. They are also involved in a number of pathological conditions being important drug targets. In this work, four vasopressin analogues substituted at position 2 with 3,3'-diphenylalanine have been docked into partially flexible vasopressin and oxytocin receptors. The bulky residue at position 2 acts as a structural restraint much stronger in the oxytocin receptor (OTR) than in the vasopressin V2 receptor (V2R), resulting in a different location of the analogues in these receptors. This explains the different, either agonistic or antagonistic, activities of the analogues in V2R and OTR, respectively. In all complexes, the conserved polar residues serve as anchor points for the ligand both in OTR and V2R. Strong interactions of the C-terminus of analogue II ([Mpa(1) ,d-Dpa(2) ,Val(4) ,d-Arg(8) ]VP) with extracellular loop 3 may be responsible for its highest activity at V2R. It also appears that V2R adapts more readily to the docking analogues by conformational changes in the aromatic side chains triggering receptor activation. A weak activity at V1a vasopressin receptor appears to be caused by weak receptor-ligand interactions. Results of this study may facilitate a rational design of new analogues with the highest activity/selectivity at vasopressin and OTRs.
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Affiliation(s)
- Magdalena J Slusarz
- Faculty of Chemistry, University of Gdańsk, Sobieskiego 18, 80-952, Gdańsk, Poland.
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Manning M, Misicka A, Olma A, Bankowski K, Stoev S, Chini B, Durroux T, Mouillac B, Corbani M, Guillon G. Oxytocin and vasopressin agonists and antagonists as research tools and potential therapeutics. J Neuroendocrinol 2012; 24:609-28. [PMID: 22375852 PMCID: PMC3490377 DOI: 10.1111/j.1365-2826.2012.02303.x] [Citation(s) in RCA: 308] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 02/17/2012] [Accepted: 02/17/2012] [Indexed: 01/08/2023]
Abstract
We recently reviewed the status of peptide and nonpeptide agonists and antagonists for the V(1a), V(1b) and V(2) receptors for arginine vasopressin (AVP) and the oxytocin receptor for oxytocin (OT). In the present review, we update the status of peptides and nonpeptides as: (i) research tools and (ii) therapeutic agents. We also present our recent findings on the design of fluorescent ligands for V(1b) receptor localisation and for OT receptor dimerisation. We note the exciting discoveries regarding two novel naturally occurring analogues of OT. Recent reports of a selective VP V(1a) agonist and a selective OT agonist point to the continued therapeutic potential of peptides in this field. To date, only two nonpeptides, the V(2) /V(1a) antagonist, conivaptan and the V(2) antagonist tolvaptan have received Food and Drug Administration approval for clinical use. The development of nonpeptide AVP V(1a), V(1b) and V(2) antagonists and OT agonists and antagonists has recently been abandoned by Merck, Sanofi and Pfizer. A promising OT antagonist, Retosiban, developed at Glaxo SmithKline is currently in a Phase II clinical trial for the prevention of premature labour. A number of the nonpeptide ligands that were not successful in clinical trials are proving to be valuable as research tools. Peptide agonists and antagonists continue to be very widely used as research tools in this field. In this regard, we present receptor data on some of the most widely used peptide and nonpeptide ligands, as a guide for their use, especially with regard to receptor selectivity and species differences.
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Affiliation(s)
- M Manning
- Biochemistry and Cancer Biology, University of Toledo College of Medicine, Toledo, OH 43614-2598, USA.
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Gruber CW, Muttenthaler M. Discovery of defense- and neuropeptides in social ants by genome-mining. PLoS One 2012; 7:e32559. [PMID: 22448224 PMCID: PMC3308954 DOI: 10.1371/journal.pone.0032559] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 01/29/2012] [Indexed: 11/18/2022] Open
Abstract
Natural peptides of great number and diversity occur in all organisms, but analyzing their peptidome is often difficult. With natural product drug discovery in mind, we devised a genome-mining approach to identify defense- and neuropeptides in the genomes of social ants from Atta cephalotes (leaf-cutter ant), Camponotus floridanus (carpenter ant) and Harpegnathos saltator (basal genus). Numerous peptide-encoding genes of defense peptides, in particular defensins, and neuropeptides or regulatory peptide hormones, such as allatostatins and tachykinins, were identified and analyzed. Most interestingly we annotated genes that encode oxytocin/vasopressin-related peptides (inotocins) and their putative receptors. This is the first piece of evidence for the existence of this nonapeptide hormone system in ants (Formicidae) and supports recent findings in Tribolium castaneum (red flour beetle) and Nasonia vitripennis (parasitoid wasp), and therefore its confinement to some basal holometabolous insects. By contrast, the absence of the inotocin hormone system in Apis mellifera (honeybee), another closely-related member of the eusocial Hymenoptera clade, establishes the basis for future studies on the molecular evolution and physiological function of oxytocin/vasopressin-related peptides (vasotocin nonapeptide family) and their receptors in social insects. Particularly the identification of ant inotocin and defensin peptide sequences will provide a basis for future pharmacological characterization in the quest for potent and selective lead compounds of therapeutic value.
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Affiliation(s)
- Christian W Gruber
- Medical University of Vienna, Center for Physiology and Pharmacology, Vienna, Austria.
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35
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Leung CH, Abebe DF, Earp SE, Goode CT, Grozhik AV, Mididoddi P, Maney DL. Neural distribution of vasotocin receptor mRNA in two species of songbird. Endocrinology 2011; 152:4865-81. [PMID: 22067316 PMCID: PMC6590851 DOI: 10.1210/en.2011-1394] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The neurohypophyseal hormones vasopressin and oxytocin are produced and released within the mammalian brain, where they act via multiple receptor subtypes. The neural distributions of these receptors, for example, V1a and oxytocin receptors, have been well described in many mammals. In birds, the distribution of binding sites for the homologous neuropeptides, vasotocin (VT) and mesotocin, has been studied in several species by using synthetic radioligands designed to bind to mammalian receptors. Such binding studies, however, may not reveal the specific distributions of each receptor subtype. To identify and map the receptors likely to bind VT and mesotocin, we generated partial cDNA sequences for four VT receptor subtypes, VT1, VT2 (V1b), VT3 (oxytocin-like), and VT4 (V1a), in white-throated sparrow (Zonotrichia albicollis) and zebra finch (Taeniopygia guttata). These genes shared high sequence identity with the homologous avian and mammalian neurohypophyseal peptide receptors, and we found evidence for VT1, VT3, and VT4 receptor mRNA expression throughout the brains of both species. As has been described in rodents, there was striking interspecific and intraspecific variation in the densities and distribution of these receptors. For example, whereas the VT1 receptor mRNA was more widespread in zebra finch brain, the VT3 (oxytocin-like) receptor mRNA was more prevalent in the sparrow brain. Although VT2 (V1b) receptor mRNA was abundant in the pituitary, it was not found in the brain. Because of their association with brain regions implicated in social behavior, the VT1, VT3, and VT4 receptors are all likely candidates for mediating the behavioral effects of VT.
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Affiliation(s)
- Cary H Leung
- Department of Psychology, Emory University, Atlanta, Georgia 30322, USA
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Busnelli M, Saulière A, Manning M, Bouvier M, Galés C, Chini B. Functional selective oxytocin-derived agonists discriminate between individual G protein family subtypes. J Biol Chem 2011; 287:3617-29. [PMID: 22069312 DOI: 10.1074/jbc.m111.277178] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We used a bioluminescence resonance energy transfer biosensor to screen for functional selective ligands of the human oxytocin (OT) receptor. We demonstrated that OT promoted the direct engagement and activation of G(q) and all the G(i/o) subtypes at the OT receptor. Other peptidic analogues, chosen because of specific substitutions in key OT structural/functional residues, all showed biased activation of G protein subtypes. No ligand, except OT, activated G(oA) or G(oB), and, with only one exception, all of the peptides that activated G(q) also activated G(i2) and G(i3) but not G(i1), G(oA), or G(oB), indicating a strong bias toward these subunits. Two peptides (DNalOVT and atosiban) activated only G(i1) or G(i3), failed to recruit β-arrestins, and did not induce receptor internalization, providing the first clear examples of ligands differentiating individual G(i/o) family members. Both analogs inhibited cell proliferation, showing that a single G(i) subtype-mediated pathway is sufficient to prompt this physiological response. These analogs represent unique tools for examining the contribution of G(i/o) members in complex biological responses and open the way to the development of drugs with peculiar selectivity profiles. This is of particular relevance because OT has been shown to improve symptoms in neurodevelopmental and psychiatric disorders characterized by abnormal social behaviors, such as autism. Functional selective ligands, activating a specific G protein signaling pathway, may possess a higher efficacy and specificity on OT-based therapeutics.
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Affiliation(s)
- Marta Busnelli
- Consiglio Nazionale delle Ricerche Institute of Neuroscience, Via Vanvitelli 32, Milan 20143, Italy
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Gordon I, Martin C, Feldman R, Leckman JF. Oxytocin and social motivation. Dev Cogn Neurosci 2011; 1:471-93. [PMID: 21984889 PMCID: PMC3185363 DOI: 10.1016/j.dcn.2011.07.007] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 07/07/2011] [Accepted: 07/13/2011] [Indexed: 12/22/2022] Open
Abstract
Humans are fundamentally social creatures who are ‘motivated’ to be with others. In this review we examine the role of oxytocin (OT) as it relates to social motivation. OT is synthesized in the brain and throughout the body, including in the heart, thymus, gastrointestinal tract, as well as reproductive organs. The distribution of the OT receptor (OTR) system in both the brain and periphery is even more far-reaching and its expression is subject to changes over the course of development. OTR expression is also sensitive to changes in the external environment and the internal somatic world. The OT system functions as an important element within a complex, developmentally sensitive biobehavioral system. Other elements include sensory inputs, the salience, reward, and threat detection pathways, the hypothalamic-pituitary-gonadal axis, and the hypothalamic-pituitary-adrenal stress response axis. Despite an ever expanding scientific literature, key unresolved questions remain concerning the interplay of the central and peripheral components of this complex biobehavioral system that dynamically engages the brain and the body as humans interact with social partners over the course of development.
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Affiliation(s)
- Ilanit Gordon
- Child Study Center, Yale University, New Haven, CT, USA
| | - Carina Martin
- Child Study Center, Yale University, New Haven, CT, USA
| | - Ruth Feldman
- Child Study Center, Yale University, New Haven, CT, USA
- Psychology Department and Gonda Brain Research Center, Bar Ilan University, Israel
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Pharmacologic rescue of impaired cognitive flexibility, social deficits, increased aggression, and seizure susceptibility in oxytocin receptor null mice: a neurobehavioral model of autism. Biol Psychiatry 2011; 69:875-82. [PMID: 21306704 DOI: 10.1016/j.biopsych.2010.12.022] [Citation(s) in RCA: 263] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 12/15/2010] [Accepted: 12/15/2010] [Indexed: 01/29/2023]
Abstract
BACKGROUND Oxytocin (OT) has been suggested as a treatment to improve social behavior in autistic patients. Accordingly, the OT (Oxt(-/-)) and the OT receptor null mice (Oxtr(-/-)) display autistic-like deficits in social behavior, increased aggression, and reduced ultrasonic vocalization. METHODS Oxtr(-/-) mice were characterized for general health, sociability, social novelty, cognitive flexibility, aggression, and seizure susceptibility. Because vasopressin (AVP) and OT cooperate in controlling social behavior, learning, and aggression, they were tested for possible rescue of the impaired behaviors. Primary hyppocampal cultures from Oxtr(+/+) and Oxtr(-/-) mouse embryos were established to investigate the balance between gamma-aminobutyric acid (GABA) and glutamate synapses and the expression levels of OT and AVP (V1a) receptors were determined by autoradiography. RESULTS Oxtr(-/-) mice display two additional, highly relevant, phenotypic characteristics: 1) a resistance to change in a learned pattern of behavior, comparable to restricted interests and repetitive behavior in autism, and 2) an increased susceptibility to seizures, a frequent and clinically relevant symptom of autism. We also show that intracerebral administration of both OT and AVP lowers aggression and fully reverts social and learning defects by acting on V1a receptors and that seizure susceptibility is antagonized by peripherally administered OT. Finally, we detect a decreased ratio of GABA-ergic versus total presynapses in hippocampal neurons of Oxtr(-/-) mice. CONCLUSIONS Autistic-like symptoms are rescued on administration of AVP and OT to young Oxtr(-/-) adult animals. The Oxtr(-/-) mouse is thus instrumental to investigate the neurochemical and synaptic abnormalities underlying autistic-like disturbances and to test new strategies of pharmacologic intervention.
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Gruber CW, Muttenthaler M, Freissmuth M. Ligand-based peptide design and combinatorial peptide libraries to target G protein-coupled receptors. Curr Pharm Des 2011; 16:3071-88. [PMID: 20687879 DOI: 10.2174/138161210793292474] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 07/21/2010] [Indexed: 01/20/2023]
Abstract
G protein-coupled receptors (GPCRs) are considered to represent the most promising drug targets; it has been repeatedly said that a large fraction of the currently marketed drugs elicit their actions by binding to GPCRs (with cited numbers varying from 30-50%). Closer scrutiny, however, shows that only a modest fraction of (≈60) GPCRs are, in fact, exploited as drug targets, only ≈20 of which are peptide-binding receptors. The vast majority of receptors in the humane genome have not yet been explored as sites of action for drugs. Given the drugability of this receptor class, it appears that opportunities for drug discovery abound. In addition, GPCRs provide for binding sites other than the ligand binding sites (referred to as the "orthosteric site"). These additional sites include (i) binding sites for ligands (referred to as "allosteric ligands") that modulate the affinity and efficacy of orthosteric ligands, (ii) the interaction surface that recruits G proteins and arrestins, (iii) the interaction sites of additional proteins (GIPs, GPCR interacting proteins that regulate G protein signaling or give rise to G protein-independent signals). These sites can also be targeted by peptides. Combinatorial and natural peptide libraries are therefore likely to play a major role in identifying new GPCR ligands at each of these sites. In particular the diverse natural peptide libraries such as the venom peptides from marine cone-snails and plant cyclotides have been established as a rich source of drug leads. High-throughput screening and combinatorial chemistry approaches allow for progressing from these starting points to potential drug candidates. This will be illustrated by focusing on the ligand-based drug design of oxytocin (OT) and vasopressin (AVP) receptor ligands using natural peptide leads as starting points.
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Affiliation(s)
- Christian W Gruber
- Institute of Pharmacology, Center of Biomolecular Medicine & Pharmacology, Medical University of Vienna, Waehringer Str. 13a, A-1090 Vienna, Austria
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Searcy BT, Bradford CS, Thompson RR, Filtz TM, Moore FL. Identification and characterization of mesotocin and V1a-like vasotocin receptors in a urodele amphibian, Taricha granulosa. Gen Comp Endocrinol 2011; 170:131-43. [PMID: 20920503 DOI: 10.1016/j.ygcen.2010.09.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 09/13/2010] [Accepted: 09/24/2010] [Indexed: 11/24/2022]
Abstract
The cDNA sequences encoding the mesotocin receptor (MTR) and vasotocin 1a receptor (VTR-1a) were identified in a urodele amphibian, the rough-skinned newt, Taricha granulosa. Saturation binding of [(3)H]oxytocin (OT) to the Taricha MTR (tMTR) was best fit by a two-state model; a high affinity-low abundance site and a lower affinity-high abundance site. Competition-binding studies found the following rank-order affinities for the tMTR: mesotocin (MT)>OT≈vasotocin (VT)>vasopressin (VP)>isotocin (IT). Inositol phosphate (IP) accumulation studies demonstrated functional activity of both the tMTR and Taricha VTR-1a (tVTR-1a) in a heterologous cell culture system. The rank-order potencies for the tMTR were MT>OT>VT≈VP>IT. The combined binding and IP results indicate that VT may act as a partial agonist of the tMTR. Rank-order potencies for the tVTR-1a were VT>VP>MT≈OT>IT. For both receptors, stimulation of IP accumulation was blocked by d(CH(2))(5)[Tyr(Me)(2)]AVP (Manning compound) and d(CH(2))(5)[Tyr(Me)(2),Thr(4),Tyr-NH(2)]OVT (OTA). OTA was a more potent antagonist for the transiently expressed tMTR while Manning compound was relatively more potent at inhibiting IP accumulation in tVTR-1a expressing cells. In contradiction to earlier assumptions, the absolute IC(50) of Manning compound was lower for the tMTR (27nM±13) than the tVTR-1a (586nM±166) indicating its potential higher affinity for the tMTR, a finding with special relevance to interpretation of comparative studies investigating the behavioral and physiological actions of neurohypophysial peptides in non-mammalian species.
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Affiliation(s)
- Brian T Searcy
- Zoology Department, Oregon State University, Corvallis, OR, USA.
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Iturrioz X, Gerbier R, Leroux V, Alvear-Perez R, Maigret B, Llorens-Cortes C. By interacting with the C-terminal Phe of apelin, Phe255 and Trp259 in helix VI of the apelin receptor are critical for internalization. J Biol Chem 2010; 285:32627-37. [PMID: 20675385 DOI: 10.1074/jbc.m110.127167] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Apelin is the endogenous ligand of the orphan seven-transmembrane domain (TM) G protein-coupled receptor APJ. Apelin is involved in the regulation of body fluid homeostasis and cardiovascular functions. We previously showed the importance of the C-terminal Phe of apelin 17 (K17F) in the hypotensive activity of this peptide. Here, we show either by deleting the Phe residue (K16P) or by substituting it by an Ala (K17A), that it plays a crucial role in apelin receptor internalization but not in apelin binding or in Gα(i)-protein coupling. Then we built a homology three-dimensional model of the human apelin receptor using the cholecystokinin receptor-1 model as a template, and we subsequently docked K17F into the binding site. We visualized a hydrophobic cavity at the bottom of the binding pocket in which the C-terminal Phe of K17F was embedded by Trp(152) in TMIV and Trp(259) and Phe(255) in TMVI. Using molecular modeling and site-directed mutagenesis studies, we further showed that Phe(255) and Trp(259) are key residues in triggering receptor internalization without playing a role in apelin binding or in Gα(i)-protein coupling. These findings bring new insights into apelin receptor activation and show that Phe(255) and Trp(259), by interacting with the C-terminal Phe of the pyroglutamyl form of apelin 13 (pE13F) or K17F, are crucial for apelin receptor internalization.
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Affiliation(s)
- Xavier Iturrioz
- INSERM, U691, Collège de France, Université Pierre et Marie-Curie Paris 6, Paris FR-75005, France
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42
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Albizu L, Cottet M, Kralikova M, Stoev S, Seyer R, Brabet I, Roux T, Bazin H, Bourrier E, Lamarque L, Breton C, Rives ML, Newman A, Javitch J, Trinquet E, Manning M, Pin JP, Mouillac B, Durroux T. Time-resolved FRET between GPCR ligands reveals oligomers in native tissues. Nat Chem Biol 2010; 6:587-94. [PMID: 20622858 DOI: 10.1038/nchembio.396] [Citation(s) in RCA: 261] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 05/07/2010] [Indexed: 01/03/2023]
Abstract
G protein-coupled receptor (GPCR) oligomers have been proposed to play critical roles in cell signaling, but confirmation of their existence in a native context remains elusive, as no direct interactions between receptors have been reported. To demonstrate their presence in native tissues, we developed a time-resolved FRET strategy that is based on receptor labeling with selective fluorescent ligands. Specific FRET signals were observed with four different receptors expressed in cell lines, consistent with their dimeric or oligomeric nature in these transfected cells. More notably, the comparison between FRET signals measured with sets of fluorescent agonists and antagonists was consistent with an asymmetric relationship of the two protomers in an activated GPCR dimer. Finally, we applied the strategy to native tissues and succeeded in demonstrating the presence of oxytocin receptor dimers and/or oligomers in mammary gland.
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Affiliation(s)
- Laura Albizu
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique, Montpellier, France
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43
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Olszewski PK, Klockars A, Schiöth HB, Levine AS. Oxytocin as feeding inhibitor: maintaining homeostasis in consummatory behavior. Pharmacol Biochem Behav 2010; 97:47-54. [PMID: 20595062 DOI: 10.1016/j.pbb.2010.05.026] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 05/12/2010] [Accepted: 05/26/2010] [Indexed: 12/13/2022]
Abstract
Initial studies showed that the anorexigenic peptide oxytocin (OT) regulates gastric motility, responds to stomach distention and to elevated osmolality, and blocks consumption of toxic foods. Most recently, it has been proposed to act as a mediator of general and carbohydrate-specific satiety and regulator of body weight. In the current review, we discuss the function of OT as a homeostatic inhibitor of consumption, capable of mitigating multiple aspects of ingestive behavior and energy metabolism.
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Affiliation(s)
- Pawel K Olszewski
- Minnesota Obesity Center, Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108, USA
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44
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Frantz MC, Rodrigo J, Boudier L, Durroux T, Mouillac B, Hibert M. Subtlety of the Structure−Affinity and Structure−Efficacy Relationships around a Nonpeptide Oxytocin Receptor Agonist. J Med Chem 2010; 53:1546-62. [DOI: 10.1021/jm901084f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marie-Céline Frantz
- Laboratoire d’Innovation Thérapeutique, UMR 7200 CNRS/Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, BP60024, 67401 Illkirch, France
| | - Jordi Rodrigo
- Laboratoire d’Innovation Thérapeutique, UMR 7200 CNRS/Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, BP60024, 67401 Illkirch, France
| | - Laure Boudier
- Institut de Génomique Fonctionnelle UMR CNRS 5203/INSERM U661/Université Montpellier I & II, Dept Pharmacologie Moléculaire, 141 rue de la Cardonille, 34094 Montpellier, France
| | - Thierry Durroux
- Institut de Génomique Fonctionnelle UMR CNRS 5203/INSERM U661/Université Montpellier I & II, Dept Pharmacologie Moléculaire, 141 rue de la Cardonille, 34094 Montpellier, France
| | - Bernard Mouillac
- Institut de Génomique Fonctionnelle UMR CNRS 5203/INSERM U661/Université Montpellier I & II, Dept Pharmacologie Moléculaire, 141 rue de la Cardonille, 34094 Montpellier, France
| | - Marcel Hibert
- Laboratoire d’Innovation Thérapeutique, UMR 7200 CNRS/Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, BP60024, 67401 Illkirch, France
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45
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Leung CH, Goode CT, Young LJ, Maney DL. Neural distribution of nonapeptide binding sites in two species of songbird. J Comp Neurol 2009; 513:197-208. [PMID: 19132730 DOI: 10.1002/cne.21947] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Vasotocin (VT) and its mammalian homologue, vasopressin (VP), modulate many social behaviors in a variety of vertebrate species. In songbirds, the effects of centrally administered VT vary according to species, which may reflect species-specific distributions of VT binding sites. Different radioligands used to map receptors in previous autoradiographical studies have revealed nonoverlapping distributions of VT binding, suggesting a heterogeneous population of more than one type of VT receptor. For two model songbird species, the white-throated sparrow (Zonotrichia albicollis) and zebra finch (Taeniopygia guttata), we labeled putative VT receptors with two radioligands, [(125)I]ornithine vasotocin analog ([(125)I]OVTA) and [(125)I]linear VP antagonist ([(125)I]HO-LVA). Competitive binding assays in the lateral septum showed that both ligands were effectively displaced by both VT and a related nonapeptide, mesotocin (MT), showing that these radioligands, which were developed to label mammalian nonapeptide receptors, label at least one population of related receptors in songbirds. [(125)I]OVTA labeled receptors throughout the telencephalon, diencephalon, midbrain, and brainstem, with a similar distribution in both species. In contrast, the binding of [(125)I]HO-LVA was restricted to the septal area, dorsal arcopallium, and optic tectum in sparrow and was essentially undetectable in zebra finch. Because the avian brain is likely to express multiple types of VT receptors, we hypothesize that the binding patterns of these radioligands represent a heterogeneous receptor population.
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Affiliation(s)
- Cary H Leung
- Department of Psychology, Emory University, Atlanta, Georgia 30322, USA.
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46
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Blume A, Bosch OJ, Miklos S, Torner L, Wales L, Waldherr M, Neumann ID. Oxytocin reduces anxiety via ERK1/2 activation: local effect within the rat hypothalamic paraventricular nucleus. Eur J Neurosci 2008; 27:1947-56. [PMID: 18412615 DOI: 10.1111/j.1460-9568.2008.06184.x] [Citation(s) in RCA: 195] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The neuropeptide oxytocin (OT) modulates social behaviours and is an important anxiolytic substance of the brain. However, sites of action and the intracellular signalling pathways downstream of OT receptors (OTR) within the brain remain largely unknown. In the present studies, we localized the anxiolytic effect of OT by bilateral microinfusion of OT (0.01 nmol/0.5 microL) into the hypothalamic paraventricular nucleus (PVN) in male rats using both the elevated plus-maze and the light-dark box. Moreover, intracerebroventricular administration of OT, but not of the related neuropeptide vasopressin (VP), dose-dependently activated the extracellular signal-regulated kinase 1/2 (ERK1/2) cascade. Specifically, OT induced the phosphorylation of Raf-1, MEK1/2 and ERK1/2 in the hypothalamus in vivo and in hypothalamic H32 neurons via EGF receptors. OT-induced ERK1/2 phosphorylation was immunohistochemically localized within VP neurons of the PVN and the supraoptic nucleus. Importantly, the anxiolytic effect of OT within the PVN was prevented by local inhibition of the MAP kinase cascade with a MEK1/2 inhibitor (U0126, 0.5 nmol/0.5 microL) locally infused prior to OT, indicating the causal involvement of this intracellular signalling cascade in the behavioural effect of OT. OT effects within the hypothalamus may have far-reaching implications for the regulation of emotionality and social behaviours and, consequently, for the development of possible therapeutic strategies to treat affective disorders. Thus, OTR agonism or activation of the ERK1/2 cascade, specifically within the hypothalamus, may provide therapeutically relevant mechanisms.
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Affiliation(s)
- Annegret Blume
- Department of Behavioural and Molecular Neuroendocrinology, Institute of Zoology, University of Regensburg, Germany
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47
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Dutertre S, Croker D, Daly NL, Andersson A, Muttenthaler M, Lumsden NG, Craik DJ, Alewood PF, Guillon G, Lewis RJ. Conopressin-T from Conus tulipa reveals an antagonist switch in vasopressin-like peptides. J Biol Chem 2008; 283:7100-8. [PMID: 18174156 DOI: 10.1074/jbc.m706477200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We report the discovery of conopressin-T, a novel bioactive peptide isolated from Conus tulipa venom. Conopressin-T belongs to the vasopressin-like peptide family and displays high sequence homology to the mammalian hormone oxytocin (OT) and to vasotocin, the endogenous vasopressin analogue found in teleost fish, the cone snail's prey. Conopressin-T was found to act as a selective antagonist at the human V 1a receptor. All peptides in this family contain two conserved amino acids within the exocyclic tripeptide (Pro7 and Gly9), which are replaced with Leu7 and Val9 in conopressin-T. Whereas conopressin-T binds only to OT and V 1a receptors, an L7P analogue had increased affinity for the V 1a receptor and weak V2 receptor binding. Surprisingly, replacing Gly9 with Val9 in OT and vasopressin revealed that this position can function as an agonist/antagonist switch at the V 1a receptor. NMR structures of both conopressin-T and L7P analogue revealed a marked difference in the orientation of the exocyclic tripeptide that may serve as templates for the design of novel ligands with enhanced affinity for the V 1a receptor.
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Affiliation(s)
- Sébastien Dutertre
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
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48
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Jójárt B, Balogh B, Márki A. Modeling the human oxytocin receptor for drug discovery efforts. Expert Opin Drug Discov 2007; 2:1579-90. [PMID: 23488902 DOI: 10.1517/17460441.2.12.1579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The oxytocin receptor belongs to class A receptors within the great family of G protein-coupled receptors. The endogenous ligand oxytocin is a nonapeptide hormone that induces the uterine contractions at parturition and is used to induce the labor. The peptide oxytocin and, even more, its non-peptide antagonist, could be valuable tools in tocolysis. The knowledge of the three-dimensional structure of the oxytocin receptor and the determination of the main interaction points between the receptor and the ligands may help to develop selective oxytocin agonists and antagonist. This review summarizes the knowledge about the mapping of the binding domain of the oxytocin receptor and the efforts in the field of molecular modeling studies related to oxytocin receptor-ligand interactions.
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Affiliation(s)
- Balázs Jójárt
- University of Szeged, Department of Chemistry and Chemical Informatics, Faculty of Education, Boldogasszony sgt. 6. 6725 Szeged, Hungary +36 62 544 720 ; +36 62 420 953 ;
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49
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Chini B, Manning M. Agonist selectivity in the oxytocin/vasopressin receptor family: new insights and challenges. Biochem Soc Trans 2007; 35:737-41. [PMID: 17635137 DOI: 10.1042/bst0350737] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The design and development of selective agonists acting at the OT (oxytocin)/AVP (vasopressin) receptors has been and continues to be a difficult task because of the great similarity among the different receptor subtypes as well as the high degree of chemical similarity between the active ligands. In recent decades, at least a thousand synthetic peptides have been synthesized and examined for their ability to bind to and activate the different OT/AVP receptors; an effort that has led to the identification of several receptor subtype-selective agonists in the rat. However, owing to species differences between rat and human AVP/OT receptors, these peptides do not exhibit the same selectivities in human receptor assays. Furthermore, the discovery of receptor promiscuity, which is the ability of a single receptor subtype to couple to several different G-proteins, has led to the definition of a completely new class of compounds, referred to here as coupling-selective ligands, which may activate, within a single receptor subtype, only a specific signalling pathway. Finally, the accumulating evidence that GPCRs (G-protein-coupled receptors) do not function as monomers, but as dimers/oligomers, opens up the design of another class of specific ligands, bivalent ligands, in which two agonist and/or antagonist moieties are joined by a spacer of the appropriate length to allow the simultaneous binding at the two subunits within the dimer. The pharmacological properties and selectivity profiles of these bivalent ligands, which remain to be investigated, could lead to highly novel research tools and potential therapeutic agents.
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Affiliation(s)
- B Chini
- CNR Institute of Neuroscience, Department of Pharmacology, University of Milan, via Vanvitelli 32, 20129 Milan, Italy.
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50
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Gassanov N, Jankowski M, Danalache B, Wang D, Grygorczyk R, Hoppe UC, Gutkowska J. Arginine vasopressin-mediated cardiac differentiation: insights into the role of its receptors and nitric oxide signaling. J Biol Chem 2007; 282:11255-65. [PMID: 17298949 DOI: 10.1074/jbc.m610769200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Despite the existence of a functional arginine vasopressin (AVP) system in the adult heart and evidence that AVP induces myogenesis, its significance in cardiomyogenesis is currently unknown. In the present study, we hypothesized a role for AVP in cardiac differentiation of D3 and lineage-specific embryonic stem (ES) cells expressing green fluorescent protein under the control of atrial natriuretic peptide (Anp) or myosin light chain-2V (Mlc-2V) promoters. Furthermore, we investigated the nitric oxide (NO) involvement in AVP-mediated pathways. AVP exposure increased the number of beating embryoid bodies, fluorescent cells, and expression of Gata-4 and other cardiac genes. V1a and V2 receptors (V1aR and V2R) differentially mediated these effects in transgenic ES cells, and exhibited a distinct developmentally regulated mRNA expression pattern. A NO synthase inhibitor, L-NAME, powerfully antagonized the AVP-induced effects on cardiogenic differentiation, implicating NO signaling in AVP-mediated pathways. Indeed, AVP elevated the mRNA and protein levels of endothelial NO synthase (eNOS) through V2R stimulation. Remarkably, increased beating activity was found in AVP-treated ES cells with down-regulated eNOS expression, indicating the significant involvement of additional pathways in cardiomyogenic effects of AVP. Finally, patch clamp recordings revealed specific AVP-induced changes of action potentials and increased L-type Ca2+ (ICa,L) current densities in differentiated ventricular phenotypes. Thus, AVP promotes cardiomyocyte differentiation of ES cells and involves Gata-4 and NO signaling. AVP-induced action potential prolongation appears likely to be linked to the increased ICa,L current in ventricular cells. In conclusion, this report provides new evidence for the essential role of the AVP system in ES cell-derived cardiomyogenesis.
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Affiliation(s)
- Natig Gassanov
- Department of Internal Medicine III, University of Cologne, 50924 Cologne, Germany
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