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Rais Y, Drabovich AP. Identification and Quantification of Human Relaxin Proteins by Immunoaffinity-Mass Spectrometry. J Proteome Res 2024. [PMID: 38739617 DOI: 10.1021/acs.jproteome.4c00027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The human relaxins belong to the Insulin/IGF/Relaxin superfamily of peptide hormones, and their physiological function is primarily associated with reproduction. In this study, we focused on a prostate tissue-specific relaxin RLN1 (REL1_HUMAN protein) and a broader tissue specificity RLN2 (REL2_HUMAN protein). Due to their structural similarity, REL1 and REL2 proteins were collectively named a 'human relaxin protein' in previous studies and were exclusively measured by immunoassays. We hypothesized that the highly selective and sensitive immunoaffinity-selected reaction monitoring (IA-SRM) assays would reveal the identity and abundance of the endogenous REL1 and REL2 in biological samples and facilitate the evaluation of these proteins for diagnostic applications. High levels of RLN1 and RLN2 transcripts were found in prostate and breast cancer cell lines by RT-PCR. However, no endogenous prorelaxin-1 or mature REL1 were detected by IA-SRM in cell lines, seminal plasma, or blood serum. The IA-SRM assay of REL2 demonstrated its undetectable levels (<9.4 pg/mL) in healthy control female and male sera and relatively high levels of REL2 in maternal sera across different gestational weeks (median 331 pg/mL; N = 120). IA-SRM assays uncovered potential cross-reactivity and nonspecific binding for relaxin immunoassays. The developed IA-SRM assays will facilitate the investigation of the physiological and pathological roles of REL1 and REL2 proteins.
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Affiliation(s)
- Yasmine Rais
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - Andrei P Drabovich
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
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2
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Chen D, Rehfeld JF, Watts AG, Rorsman P, Gundlach AL. History of key regulatory peptide systems and perspectives for future research. J Neuroendocrinol 2023; 35:e13251. [PMID: 37053148 DOI: 10.1111/jne.13251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/10/2023] [Accepted: 02/26/2023] [Indexed: 03/06/2023]
Abstract
Throughout the 20th Century, regulatory peptide discovery advanced from the identification of gut hormones to the extraction and characterization of hypothalamic hypophysiotropic factors, and to the isolation and cloning of multiple brain neuropeptides. These discoveries were followed by the discovery of G-protein-coupled and other membrane receptors for these peptides. Subsequently, the systems physiology associated with some of these multiple regulatory peptides and receptors has been comprehensively elucidated and has led to improved therapeutics and diagnostics and their approval by the US Food and Drug Administration. In light of this wealth of information and further potential, it is truly a time of renaissance for regulatory peptides. In this perspective, we review what we have learned from the pioneers in exemplified fields of gut peptides, such as cholecystokinin, enterochromaffin-like-cell peptides, and glucagon, from the trailblazing studies on the key stress hormone, corticotropin-releasing factor, as well as from more recently characterized relaxin-family peptides and receptors. The historical viewpoints are based on our understanding of these topics in light of the earliest phases of research and on subsequent studies and the evolution of knowledge, aiming to sharpen our vision of the current state-of-the-art and those studies that should be prioritized in the future.
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Affiliation(s)
- Duan Chen
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Jens F Rehfeld
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Alan G Watts
- Department of Biological Sciences, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California, USA
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
- Florey Department of Neuroscience and Mental Health and Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC, Australia
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3
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Gay EA, Guan D, Van Voorhies K, Vasukuttan V, Mathews KM, Besheer J, Jin C. Discovery and Characterization of the First Nonpeptide Antagonists for the Relaxin-3/RXFP3 System. J Med Chem 2022; 65:7959-7974. [PMID: 35594150 DOI: 10.1021/acs.jmedchem.2c00508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The neuropeptide relaxin-3/RXFP3 system is involved in many important physiological processes such as stress responses, appetite control, and motivation for reward. To date, pharmacological studies of RXFP3 have been limited to peptide ligands. In this study, we report the discovery of the first small-molecule antagonists of RXFP3 through a high-throughput screening campaign. Focused structure-activity relationship studies of the hit compound resulted in RLX-33 (33) that was able to inhibit relaxin-3 activity in a battery of functional assays. RLX-33 is selective for RXFP3 over RXFP1 and RXFP4, two related members in the relaxin/insulin superfamily, and has favorable pharmacokinetic properties for behavioral assessment. When administered to rats intraperitoneally, RLX-33 blocked food intake induced by the RXFP3-selective agonist R3/I5. Collectively, our findings demonstrated that RLX-33 represents a promising antagonist scaffold for the development of drugs targeting the relaxin-3/RXFP3 system.
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Affiliation(s)
- Elaine A Gay
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, Research Triangle Park, North Carolina 27709, United States
| | - Dongliang Guan
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, Research Triangle Park, North Carolina 27709, United States
| | - Kalynn Van Voorhies
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Vineetha Vasukuttan
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, Research Triangle Park, North Carolina 27709, United States
| | - Kelly M Mathews
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, Research Triangle Park, North Carolina 27709, United States
| | - Joyce Besheer
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Chunyang Jin
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, Research Triangle Park, North Carolina 27709, United States
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4
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Gołyszny M, Obuchowicz E, Zieliński M. Neuropeptides as regulators of the hypothalamus-pituitary-gonadal (HPG) axis activity and their putative roles in stress-induced fertility disorders. Neuropeptides 2022; 91:102216. [PMID: 34974357 DOI: 10.1016/j.npep.2021.102216] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/21/2021] [Accepted: 10/05/2021] [Indexed: 11/24/2022]
Abstract
Neuropeptides being regulators of the hypothalamus-pituitary-adrenal (HPA) axis activity, also affect the function of the hypothalamus-pituitary-gonadal (HPG) axis by regulating gonadotrophin-releasing hormone (GnRH) secretion from hypothalamic neurons. Here, we review the available data on how neuropeptides affect HPG axis activity directly or indirectly via their influence on the HPA axis. The putative role of neuropeptides in stress-induced infertility, such as polycystic ovary syndrome, is also described. This review discusses both well-known neuropeptides (i.e., kisspeptin, Kp; oxytocin, OT; arginine-vasopressin, AVP) and more recently discovered peptides (i.e., relaxin-3, RLN-3; nesfatin-1, NEFA; phoenixin, PNX; spexin, SPX). For the first time, we present an up-to-date review of all published data regarding interactions between the aforementioned neuropeptide systems. The reviewed literature suggest new pathophysiological mechanisms leading to fertility disturbances that are induced by stress.
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Affiliation(s)
- Miłosz Gołyszny
- Department of Pharmacology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 Street, 40-752 Katowice, Poland.
| | - Ewa Obuchowicz
- Department of Pharmacology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 Street, 40-752 Katowice, Poland.
| | - Michał Zieliński
- Department of Pharmacology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 Street, 40-752 Katowice, Poland.
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5
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Wong WLE, Dawe GS, Young AH. The putative role of the relaxin-3/RXFP3 system in clinical depression and anxiety: A systematic literature review. Neurosci Biobehav Rev 2021; 131:429-450. [PMID: 34537263 DOI: 10.1016/j.neubiorev.2021.09.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 09/13/2021] [Accepted: 09/13/2021] [Indexed: 12/14/2022]
Abstract
The relaxin-3/RXFP3 system is one of several neuropeptidergic systems putatively implicated in regulating the behavioural alterations that characterise clinical depression and anxiety, making it a potential target for clinical translation. Accordingly, this systematic review identified published reports on the role of relaxin-3/RXFP3 signalling in these neuropsychiatric disorders and their behavioural endophenotypes, evaluating evidence from animal and human studies to ascertain any relationship. We searched PubMed, EMBASE, PsycINFO and Google Scholar databases up to February 2021, finding 609 relevant records. After stringent screening, 51 of these studies were included in the final synthesis. There was considerable heterogeneity in study designs and some inconsistency across study outcomes. However, experimental evidence is consistent with an ability of relaxin-3/RXFP3 signalling to promote arousal and suppress depressive- and anxiety-like behaviour. Moreover, meta-analyses of six to eight articles investigating food intake revealed that acute RXFP3 activation had strong orexigenic effects in rats. This appraisal also identified the lack of high-quality clinical studies pertinent to the relaxin-3/RXFP3 system, a gap that future research should attempt to bridge.
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Affiliation(s)
- Win Lee Edwin Wong
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom.
| | - Gavin Stewart Dawe
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore
| | - Allan H Young
- Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom; South London & Maudsley NHS Foundation Trust, Bethlem Royal Hospital, Monks Orchard Road, London, United Kingdom
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6
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Serelaxin (recombinant human relaxin-2) treatment affects the endogenous synthesis of long chain poly-unsaturated fatty acids and induces substantial alterations of lipidome and metabolome profiles in rat cardiac tissue. Pharmacol Res 2019; 144:51-65. [DOI: 10.1016/j.phrs.2019.04.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/25/2019] [Accepted: 04/03/2019] [Indexed: 02/07/2023]
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Aragón-Herrera A, Feijóo-Bandín S, Rodríguez-Penas D, Roselló-Lletí E, Portolés M, Rivera M, Bigazzi M, Bani D, Gualillo O, González-Juanatey JR, Lago F. Relaxin activates AMPK-AKT signaling and increases glucose uptake by cultured cardiomyocytes. Endocrine 2018; 60:103-111. [PMID: 29411306 DOI: 10.1007/s12020-018-1534-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 01/15/2018] [Indexed: 12/22/2022]
Abstract
PURPOSE Many evidences show that the hormone relaxin plays a pivotal role in the physiology and pathology of the cardiovascular system. This pleiotropic hormone exerts regulatory functions through specific receptors in cardiovascular tissues: in experimental animal models it was shown to induce coronary vasodilation, prevent cardiac damage induced by ischemia/reperfusion and revert cardiac hypertrophy and fibrosis. A tight relationship between this hormone and important metabolic pathways has been suggested, but it is at present unknown if relaxin could regulate cardiac metabolism. Our aim was to study the possible effects of relaxin on cardiomyocyte metabolism. METHODS Neonatal rat cardiomyocytes were treated with relaxin and (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assays (MTT) were performed to assess metabolic activity; while 2-deoxy-D-[3H] glucose and BODIPY-labelled fatty acid incorporations were analyzed to measure glucose and fatty acid uptakes, and western blot was utilized to study the intracellular signaling pathways activated by the hormone. RESULTS We observed that relaxin at 10 ng/ml was able to increase the level of metabolic activity of cultured neonatal rat cardiomyocytes; the rate of 2-deoxy-D-[3H]glucose incorporation demonstrated that relaxin also induced an increase in glucose uptake. First evidence is also offered that relaxin can activate the master energy sensor and regulator AMPK in cardiomyocytes. Moreover, the treatment of cardiomyocytes with relaxin also induced dose-dependent increases in ERK1/2, AKT, and AS160 phosphorylation. That raise in AS160 phosphorylation induced by relaxin was prevented by the pretreatment with AMPK and AKT pathways inhibitors, indicating that both molecules play important roles in the relaxin effects reported. CONCLUSION Relaxin can regulate cardiomyocyte metabolism and activate AMPK, the central sensor of energy status that maintains cellular energy homeostasis, and also ERK and AKT, two molecular sensing nodes that coordinate dynamic responses of the cell's metabolic responses.
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Affiliation(s)
- A Aragón-Herrera
- Cellular and Molecular Cardiology Unit and Department of Cardiology, Institute of Biomedical Research (IDIS-SERGAS), Santiago de Compostela, Spain
| | - S Feijóo-Bandín
- Cellular and Molecular Cardiology Unit and Department of Cardiology, Institute of Biomedical Research (IDIS-SERGAS), Santiago de Compostela, Spain.
- CIBERCV, Institute of Health Carlos III, Madrid, Spain.
| | - D Rodríguez-Penas
- Cellular and Molecular Cardiology Unit and Department of Cardiology, Institute of Biomedical Research (IDIS-SERGAS), Santiago de Compostela, Spain
| | - E Roselló-Lletí
- CIBERCV, Institute of Health Carlos III, Madrid, Spain
- Cardiocirculatory Unit, Health Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - M Portolés
- CIBERCV, Institute of Health Carlos III, Madrid, Spain
- Cardiocirculatory Unit, Health Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - M Rivera
- CIBERCV, Institute of Health Carlos III, Madrid, Spain
- Cardiocirculatory Unit, Health Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - M Bigazzi
- Prosperius Institute, Florence, Italy
| | - D Bani
- Prosperius Institute, Florence, Italy
| | - O Gualillo
- Neuroendocrine Interaccions in Rheumatology and Inflammatory Diseases Unit, Institute of Biomedical Research (IDIS-SERGAS), Santiago de Compostela, Spain
| | - J R González-Juanatey
- Cellular and Molecular Cardiology Unit and Department of Cardiology, Institute of Biomedical Research (IDIS-SERGAS), Santiago de Compostela, Spain
- CIBERCV, Institute of Health Carlos III, Madrid, Spain
| | - F Lago
- Cellular and Molecular Cardiology Unit and Department of Cardiology, Institute of Biomedical Research (IDIS-SERGAS), Santiago de Compostela, Spain
- CIBERCV, Institute of Health Carlos III, Madrid, Spain
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8
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Feijóo-Bandín S, Aragón-Herrera A, Rodríguez-Penas D, Portolés M, Roselló-Lletí E, Rivera M, González-Juanatey JR, Lago F. Relaxin-2 in Cardiometabolic Diseases: Mechanisms of Action and Future Perspectives. Front Physiol 2017; 8:599. [PMID: 28868039 PMCID: PMC5563388 DOI: 10.3389/fphys.2017.00599] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 08/03/2017] [Indexed: 12/13/2022] Open
Abstract
Despite the great effort of the medical community during the last decades, cardiovascular diseases remain the leading cause of death worldwide, increasing their prevalence every year mainly due to our new way of life. In the last years, the study of new hormones implicated in the regulation of energy metabolism and inflammation has raised a great interest among the scientific community regarding their implications in the development of cardiometabolic diseases. In this review, we will summarize the main actions of relaxin, a pleiotropic hormone that was previously suggested to improve acute heart failure and that participates in both metabolism and inflammation regulation at cardiovascular level, and will discuss its potential as future therapeutic target to prevent/reduce cardiovascular diseases.
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Affiliation(s)
- Sandra Feijóo-Bandín
- Cellular and Molecular Cardiology Research Unit, Institute of Biomedical Research and University Clinical HospitalSantiago de Compostela, Spain
- Centro de Investigación Biomédica en Red de Enfermedades CardiovascularesMadrid, Spain
| | - Alana Aragón-Herrera
- Cellular and Molecular Cardiology Research Unit, Institute of Biomedical Research and University Clinical HospitalSantiago de Compostela, Spain
| | - Diego Rodríguez-Penas
- Cellular and Molecular Cardiology Research Unit, Institute of Biomedical Research and University Clinical HospitalSantiago de Compostela, Spain
| | - Manuel Portolés
- Centro de Investigación Biomédica en Red de Enfermedades CardiovascularesMadrid, Spain
- Cardiocirculatory Unit, Health Research Institute of La Fe University HospitalValencia, Spain
| | - Esther Roselló-Lletí
- Centro de Investigación Biomédica en Red de Enfermedades CardiovascularesMadrid, Spain
- Cardiocirculatory Unit, Health Research Institute of La Fe University HospitalValencia, Spain
| | - Miguel Rivera
- Centro de Investigación Biomédica en Red de Enfermedades CardiovascularesMadrid, Spain
- Cardiocirculatory Unit, Health Research Institute of La Fe University HospitalValencia, Spain
| | - José R. González-Juanatey
- Cellular and Molecular Cardiology Research Unit, Institute of Biomedical Research and University Clinical HospitalSantiago de Compostela, Spain
- Centro de Investigación Biomédica en Red de Enfermedades CardiovascularesMadrid, Spain
| | - Francisca Lago
- Cellular and Molecular Cardiology Research Unit, Institute of Biomedical Research and University Clinical HospitalSantiago de Compostela, Spain
- Centro de Investigación Biomédica en Red de Enfermedades CardiovascularesMadrid, Spain
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9
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Ivell R, Agoulnik AI, Anand‐Ivell R. Relaxin-like peptides in male reproduction - a human perspective. Br J Pharmacol 2017; 174:990-1001. [PMID: 27933606 PMCID: PMC5406299 DOI: 10.1111/bph.13689] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 11/10/2016] [Accepted: 12/05/2016] [Indexed: 12/26/2022] Open
Abstract
The relaxin family of peptide hormones and their cognate GPCRs are becoming physiologically well-characterized in the cardiovascular system and particularly in female reproductive processes. Much less is known about the physiology and pharmacology of these peptides in male reproduction, particularly as regards humans. H2-relaxin is involved in prostate function and growth, while insulin-like peptide 3 (INSL3) is a major product of the testicular Leydig cells and, in the adult, appears to modulate steroidogenesis and germ cell survival. In the fetus, INSL3 is a key hormone expressed shortly after sex determination and is responsible for the first transabdominal phase of testicular descent. Importantly, INSL3 is becoming a very useful constitutive biomarker reflecting both fetal and post-natal development. Nothing is known about roles for INSL4 in male reproduction and only very little about relaxin-3, which is mostly considered as a brain peptide, or INSL5. The former is expressed at very low levels in the testes, but has no known physiology there, whereas the INSL5 knockout mouse does exhibit a testicular phenotype with mild effects on spermatogenesis, probably due to a disruption of glucose homeostasis. INSL6 is a major product of male germ cells, although it is relatively unexplored with regard to its physiology or pharmacology, except that in mice disruption of the INSL6 gene leads to a disruption of spermatogenesis. Clinically, relaxin analogues may be useful in the control of prostate cancer, and both relaxin and INSL3 have been considered as sperm adjuvants for in vitro fertilization. LINKED ARTICLES This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc.
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Affiliation(s)
- Richard Ivell
- School of BiosciencesUniversity of NottinghamNottinghamLE12 5RDUK
- School of Veterinary and Medical SciencesUniversity of NottinghamNottinghamLE12 5RDUK
| | - Alexander I Agoulnik
- Department of Human and Molecular Genetics, Herbert Wertheim College of MedicineFlorida International UniversityMiamiFLUSA
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10
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Ma S, Smith CM, Blasiak A, Gundlach AL. Distribution, physiology and pharmacology of relaxin-3/RXFP3 systems in brain. Br J Pharmacol 2016; 174:1034-1048. [PMID: 27774604 DOI: 10.1111/bph.13659] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/12/2016] [Accepted: 10/17/2016] [Indexed: 01/29/2023] Open
Abstract
Relaxin-3 is a member of a superfamily of structurally-related peptides that includes relaxin and insulin-like peptide hormones. Soon after the discovery of the relaxin-3 gene, relaxin-3 was identified as an abundant neuropeptide in brain with a distinctive topographical distribution within a small number of GABAergic neuron populations that is well conserved across species. Relaxin-3 is thought to exert its biological actions through a single class-A GPCR - relaxin-family peptide receptor 3 (RXFP3). Class-A comprises GPCRs for relaxin-3 and insulin-like peptide-5 and other peptides such as orexin and the monoamine transmitters. The RXFP3 receptor is selectively activated by relaxin-3, whereas insulin-like peptide-5 is the cognate ligand for the related RXFP4 receptor. Anatomical and pharmacological evidence obtained over the last decade supports a function of relaxin-3/RXFP3 systems in modulating responses to stress, anxiety-related and motivated behaviours, circadian rhythms, and learning and memory. Electrophysiological studies have identified the ability of RXFP3 agonists to directly hyperpolarise thalamic neurons in vitro, but there are no reports of direct cell signalling effects in vivo. This article provides an overview of earlier studies and highlights more recent research that implicates relaxin-3/RXFP3 neural network signalling in the integration of arousal, motivation, emotion and related cognition, and that has begun to identify the associated neural substrates and mechanisms. Future research directions to better elucidate the connectivity and function of different relaxin-3 neuron populations and their RXFP3-positive target neurons in major experimental species and humans are also identified. LINKED ARTICLES This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc.
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Affiliation(s)
- Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Craig M Smith
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,School of Medicine, Deakin University, Geelong, Victoria, Australia
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.,Department of Anatomy and Neuroscience, The University of Melbourne, Victoria, Australia
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11
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Kumar JR, Rajkumar R, Jayakody T, Marwari S, Hong JM, Ma S, Gundlach AL, Lai MKP, Dawe GS. Relaxin' the brain: a case for targeting the nucleus incertus network and relaxin-3/RXFP3 system in neuropsychiatric disorders. Br J Pharmacol 2016; 174:1061-1076. [PMID: 27597467 PMCID: PMC5406295 DOI: 10.1111/bph.13564] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 07/15/2016] [Indexed: 12/14/2022] Open
Abstract
Relaxin‐3 has been proposed to modulate emotional–behavioural functions such as arousal and behavioural activation, appetite regulation, stress responses, anxiety, memory, sleep and circadian rhythm. The nucleus incertus (NI), in the midline tegmentum close to the fourth ventricle, projects widely throughout the brain and is the primary site of relaxin‐3 neurons. Over recent years, a number of preclinical studies have explored the function of the NI and relaxin‐3 signalling, including reports of mRNA or peptide expression changes in the NI in response to behavioural or pharmacological manipulations, effects of lesions or electrical or pharmacological manipulations of the NI, effects of central microinfusions of relaxin‐3 or related agonist or antagonist ligands on physiology and behaviour, and the impact of relaxin‐3 gene deletion or knockdown. Although these individual studies reveal facets of the likely functional relevance of the NI and relaxin‐3 systems for human physiology and behaviour, the differences observed in responses between species (e.g. rat vs. mouse), the clearly identified heterogeneity of NI neurons and procedural differences between laboratories are some of the factors that have prevented a precise understanding of their function. This review aims to draw attention to the current preclinical evidence available that suggests the relevance of the NI/relaxin‐3 system to the pathology and/or symptoms of certain neuropsychiatric disorders and to provide cognizant directions for future research to effectively and efficiently uncover its therapeutic potential. Linked Articles This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc
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Affiliation(s)
- Jigna Rajesh Kumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore.,Singapore Institute for Neurotechnology (SINAPSE), Singapore.,NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, Singapore
| | - Ramamoorthy Rajkumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore.,Singapore Institute for Neurotechnology (SINAPSE), Singapore
| | - Tharindunee Jayakody
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore.,Singapore Institute for Neurotechnology (SINAPSE), Singapore
| | - Subhi Marwari
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore.,Singapore Institute for Neurotechnology (SINAPSE), Singapore
| | - Jia Mei Hong
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore.,Singapore Institute for Neurotechnology (SINAPSE), Singapore.,NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, Singapore
| | - Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia.,Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia
| | - Mitchell K P Lai
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Gavin S Dawe
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, Singapore.,Singapore Institute for Neurotechnology (SINAPSE), Singapore.,NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, Singapore
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Halls ML, Bathgate RAD, Sutton SW, Dschietzig TB, Summers RJ. International Union of Basic and Clinical Pharmacology. XCV. Recent advances in the understanding of the pharmacology and biological roles of relaxin family peptide receptors 1-4, the receptors for relaxin family peptides. Pharmacol Rev 2015; 67:389-440. [PMID: 25761609 DOI: 10.1124/pr.114.009472] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Relaxin, insulin-like peptide 3 (INSL3), relaxin-3, and INSL5 are the cognate ligands for the relaxin family peptide (RXFP) receptors 1-4, respectively. RXFP1 activates pleiotropic signaling pathways including the signalosome protein complex that facilitates high-sensitivity signaling; coupling to Gα(s), Gα(i), and Gα(o) proteins; interaction with glucocorticoid receptors; and the formation of hetero-oligomers with distinctive pharmacological properties. In addition to relaxin-related ligands, RXFP1 is activated by Clq-tumor necrosis factor-related protein 8 and by small-molecular-weight agonists, such as ML290 [2-isopropoxy-N-(2-(3-(trifluoromethylsulfonyl)phenylcarbamoyl)phenyl)benzamide], that act allosterically. RXFP2 activates only the Gα(s)- and Gα(o)-coupled pathways. Relaxin-3 is primarily a neuropeptide, and its cognate receptor RXFP3 is a target for the treatment of depression, anxiety, and autism. A variety of peptide agonists, antagonists, biased agonists, and an allosteric modulator target RXFP3. Both RXFP3 and the related RXFP4 couple to Gα(i)/Gα(o) proteins. INSL5 has the properties of an incretin; it is secreted from the gut and is orexigenic. The expression of RXFP4 in gut, adipose tissue, and β-islets together with compromised glucose tolerance in INSL5 or RXFP4 knockout mice suggests a metabolic role. This review focuses on the many advances in our understanding of RXFP receptors in the last 5 years, their signal transduction mechanisms, the development of novel compounds that target RXFP1-4, the challenges facing the field, and current prospects for new therapeutics.
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Affiliation(s)
- Michelle L Halls
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Ross A D Bathgate
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Steve W Sutton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Thomas B Dschietzig
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Roger J Summers
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
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Anand-Ivell R, Ivell R. Regulation of the reproductive cycle and early pregnancy by relaxin family peptides. Mol Cell Endocrinol 2014; 382:472-479. [PMID: 23994019 DOI: 10.1016/j.mce.2013.08.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 08/09/2013] [Accepted: 08/18/2013] [Indexed: 12/16/2022]
Abstract
The relaxin family of peptide hormones are structurally closely related to one another sharing a heterodimeric A-B structure, like that of insulin. They may also be active as unprocessed B-C-A pro-forms. Relaxin has been shown to pay a key role within the ovary, being involved in follicle growth, and ovulation. Relaxin is produced in large amounts also by the corpus luteum where it acts as an endocrine hormone positively affecting implantation, placentation and vascularization during the all-important first trimester phase of pregnancy establishment. Relaxin exerts its functions via the receptor RXFP1. Insulin-like peptide 3 (INSL3) in contrast acts through the related receptor RXFP2, and plays an essential role in the production of androgens within growing antral follicles. INSL3 is also produced in large amounts by the male fetus shortly after sex determination, where it controls the first transabdominal phase of testicular descent. However, this fetal INSL3 is also able to influence placental and maternal physiology, indicating associations with later preeclampsia and/or fetal growth restriction. Other members of this relaxin-like family of peptides, such as INSL4, INSL5 and INSL6 are less well studied, though all suggest modulatory roles in ovarian and/or placental function.
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Affiliation(s)
| | - Richard Ivell
- Leibniz Institute for Farm Animal Biology, 18196 Dummerstorf, Germany.
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Zhang X, Zhu M, Zhao M, Chen W, Fu Y, Liu Y, Liu W, Zhang B, Yin X, Bai B. The plasma levels of relaxin-2 and relaxin-3 in patients with diabetes. Clin Biochem 2013; 46:1713-6. [PMID: 23994775 DOI: 10.1016/j.clinbiochem.2013.08.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 08/17/2013] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Relaxin-2 has been found to alleviate fibrosis in experimental diabetic cardiomyopathy. In addition, the levels of serum relaxin-3 were increased and correlated with all the component traits of metabolic syndrome. We investigated the levels of plasma relaxin-2 or relaxin-3 and their relationship to component traits in patients with diabetes. DESIGN AND METHODS We studied 33 newly diagnosed type 2 diabetes patients and 38 age-matched healthy subjects. Blood samples were taken at study entry, and relaxin-3, relaxin-2, fasting blood glucose, total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides, serum insulin and hemoglobin A1c (HbA1c) levels were measured. RESULTS Relaxin-2 levels were significantly lower in patients with diabetes than in controls: the median plasma relaxin-2 concentration was 34.68 pg/mL (range, <29.00-50.81 pg/mL) in patients with diabetes and 45.80 pg/mL (range, <37.42-54.46 pg/mL) in controls (p=0.0150). However, no differences in relaxin-3 levels were observed between the diabetes group and controls (p=0.6550). The plasma levels of relaxin-2 or relaxin-3 were not correlated with systolic blood pressure (BP), diastolic BP, total cholesterol, LDL-C, HDL-C, triglyceride, fasting blood glucose, fasting insulin and HbA1c in patients with diabetes. Additionally, there was no correlation between the plasma concentrations of relaxin-2 and relaxin-3 in patients with diabetes (rs=0.225; p=0.208). CONCLUSIONS We conclude that the plasma levels of relaxin-2 in diabetes patients were lower than in controls, however, there are no difference in plasma relaxin-3 concentrations between controls and patients with diabetes. Relaxin-2 or relaxin-3 levels are not related to component traits in patients with diabetes.
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Affiliation(s)
- Xiaohui Zhang
- Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
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