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Liu J, Liu X, Luo Y, Huang F, Xie Y, Zheng S, Jia B, Xiao Z. Sphingolipids: drivers of cardiac fibrosis and atrial fibrillation. J Mol Med (Berl) 2024; 102:149-165. [PMID: 38015241 PMCID: PMC10858135 DOI: 10.1007/s00109-023-02391-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 10/13/2023] [Accepted: 10/23/2023] [Indexed: 11/29/2023]
Abstract
Sphingolipids (SLs) are vital constituents of the plasma membrane of animal cells and concurrently regulate numerous cellular processes. An escalating number of research have evinced that SLs assume a crucial part in the progression of tissue fibrosis, a condition for which no efficacious cure exists as of now. Cardiac fibrosis, and in particular, atrial fibrosis, is a key factor in the emergence of atrial fibrillation (AF). AF has become one of the most widespread cardiac arrhythmias globally, with its incidence continuing to mount, thereby propelling it to the status of a major public health concern. This review expounds on the structure and biosynthesis pathways of several pivotal SLs, the pathophysiological mechanisms of AF, and the function of SLs in cardiac fibrosis. Delving into the influence of sphingolipid levels in the alleviation of cardiac fibrosis offers innovative therapeutic strategies to address cardiac fibrosis and AF.
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Affiliation(s)
- Junjie Liu
- Department of Cardiovascular Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Ximao Liu
- Department of Cardiovascular Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yucheng Luo
- Department of Cardiovascular Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Fangze Huang
- Department of Cardiovascular Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yu Xie
- Department of Cardiovascular Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Shaoyi Zheng
- Department of Cardiovascular Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
| | - Bo Jia
- Department of Oral and Maxillofacial Surgery, Stomatological Hospital, School of Stomatology, Southern Medical University, Guangzhou, China.
| | - Zezhou Xiao
- Department of Cardiovascular Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
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2
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Lv C, Zheng H, Jiang B, Ren Q, Zhang J, Zhang X, Li J, Wang Y. Characterization of relaxin 3 and its receptors in chicken: Evidence for relaxin 3 acting as a novel pituitary hormone. Front Physiol 2022; 13:1010851. [DOI: 10.3389/fphys.2022.1010851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 10/12/2022] [Indexed: 11/09/2022] Open
Abstract
Mammalian relaxin (RLN) family peptides binding their receptors (RXFPs) play a variety of roles in many physiological processes, such as reproduction, stress, appetite regulation, and energy balance. In birds, although two relaxin family peptides (RLN3 and INSL5) and four receptors (RXFP1, RXFP2, RXFP2-like, and RXFP3) were predicated, their sequence features, signal properties, tissue distribution, and physiological functions remain largely unknown. In this study, using chickens as the experimental model, we cloned the cDNA of the cRLN3 gene and two receptor (cRXFP1 and cRXFP3) genes. Using cell-based luciferase reporter assays, we demonstrate that cRLN3 is able to activate both cRXFP1 and cRXFP3 for downstream signaling. cRXFP1, rather than cRXFP3, is a cognate receptor for cRLN3, which is different from the mammals. Tissue distribution analyses reveal that cRLN3 is highly expressed in the pituitary with lower abundance in the hypothalamus and ovary of female chicken, together with the detection that cRLN3 co-localizes with pituitary hormone genes LHB/FSHB/GRP/CART and its expression is tightly regulated by hypothalamic factors (GnRH and CRH) and sex steroid hormone (E2). The present study supports that cRLN3 may function as a novel pituitary hormone involving female reproduction.
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3
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Martins RC, Pintalhão M, Leite-Moreira A, Castro-Chaves P. Relaxin and the Cardiovascular System: from Basic Science to Clinical Practice. Curr Mol Med 2021; 20:167-184. [PMID: 31642776 DOI: 10.2174/1566524019666191023121607] [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: 02/08/2018] [Revised: 08/07/2019] [Accepted: 10/07/2019] [Indexed: 12/16/2022]
Abstract
The peptide hormone relaxin was originally linked to reproductive physiology, where it is believed to mediate systemic and renal hemodynamic adjustments to pregnancy. Recently, its broad range of effects in the cardiovascular system has been the focus of intensive research regarding its implications under pathological conditions and potential therapeutic potential. An understanding of the multitude of cardioprotective actions prompted the study of serelaxin, recombinant human relaxin-2, for the treatment of acute heart failure. Despite early promising results from phase II studies, recently revealed RELAX-AHF-2 outcomes were rather disappointing and the treatment for acute heart failure remains an unmet medical need. This article reviews the physiologic actions of relaxin on the cardiovascular system and its relevance in the pathophysiology of cardiovascular disease. We summarize the most updated clinical data and discuss future directions of serelaxin for the treatment of acute heart failure. This should encourage additional work to determine how can relaxin's beneficial effects be exploited for the treatment of cardiovascular disease.
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Affiliation(s)
- Rafael Clara Martins
- Department of Surgery and Physiology, Faculty of Medicine, University of Porto, Porto, Portugal.,Cardiovascular Research Centre, Porto, Portugal.,Internal Medicine Department, São João Hospital Centre, Porto, Portugal
| | - Mariana Pintalhão
- Department of Surgery and Physiology, Faculty of Medicine, University of Porto, Porto, Portugal.,Cardiovascular Research Centre, Porto, Portugal.,Internal Medicine Department, São João Hospital Centre, Porto, Portugal
| | - Adelino Leite-Moreira
- Department of Surgery and Physiology, Faculty of Medicine, University of Porto, Porto, Portugal.,Cardiovascular Research Centre, Porto, Portugal.,Cardiothoracic Surgery Department, São João Hospital Centre, Porto, Portugal
| | - Paulo Castro-Chaves
- Department of Surgery and Physiology, Faculty of Medicine, University of Porto, Porto, Portugal.,Cardiovascular Research Centre, Porto, Portugal.,Internal Medicine Department, São João Hospital Centre, Porto, Portugal
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4
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Chen TY, Li X, Hung CH, Bahudhanapati H, Tan J, Kass DJ, Zhang Y. The relaxin family peptide receptor 1 (RXFP1): An emerging player in human health and disease. Mol Genet Genomic Med 2020; 8:e1194. [PMID: 32100955 PMCID: PMC7196478 DOI: 10.1002/mgg3.1194] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/11/2020] [Indexed: 12/14/2022] Open
Abstract
Background Relaxin/relaxin family peptide receptor 1 (RXFP1) signaling is important for both normal physiology and disease. Strong preclinical evidence supports relaxin as a potent antifibrotic molecule. However, relaxin‐based therapy failed in clinical trial in patients with systemic sclerosis. We and others have discovered that aberrant expression of RXFP1 may contribute to the abnormal relaxin/RXFP1 signaling in different diseases. Reduced RXFP1 expression and alternative splicing transcripts with potential functional consequences have been observed in fibrotic tissues. A relative decrease in RXFP1 expression in fibrotic tissues—specifically lung and skin—may explain a potential insensitivity to relaxin. In addition, receptor dimerization also plays important roles in relaxin/RXFP1 signaling. Methods This review describes the tissue specific expression, characteristics of the splicing variants, and homo/heterodimerization of RXFP1 in both normal physiological function and human diseases. We discuss the potential implications of these molecular features for developing therapeutics to restore relaxin/RXFP1 signaling and to harness relaxin's potential antifibrotic effects. Results Relaxin/RXFP1 signaling is important in both normal physiology and in human diseases. Reduced expression of RXFP1 in fibrotic lung and skin tissues surrenders both relaxin/RXFP1 signaling and their responsiveness to exogenous relaxin treatments. Alternative splicing and receptor dimerization are also important in regulating relaxin/RXFP1 signaling. Conclusions Understanding the molecular mechanisms that drive aberrant expression of RXFP1 in disease and the functional roles of alternative splicing and receptor dimerization will provide insight into therapeutic targets that may restore the relaxin responsiveness of fibrotic tissues.
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Affiliation(s)
- Ting-Yun Chen
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA.,Institute of Allied Health Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Xiaoyun Li
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ching-Hsia Hung
- Institute of Allied Health Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Harinath Bahudhanapati
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jiangning Tan
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Daniel J Kass
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yingze Zhang
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA, USA
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5
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Kwok WH, Choi TLS, Leung GNW, Wong ASY, Yue SK, Wan TSM, Ho ENM. Administration study of recombinant human relaxin-2 in horse for doping control purpose. Drug Test Anal 2019; 12:361-370. [PMID: 31726484 DOI: 10.1002/dta.2732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 10/03/2019] [Accepted: 11/03/2019] [Indexed: 11/06/2022]
Abstract
The insulin-like peptide relaxin (RLX), an endogenous peptide hormone produced in human for pregnancy and reproduction, is also known to exert a range of physiological and pathological effects. Its use is banned in human sports, horseracing, and equestrian competitions due to its potential performance enhancing effect through vasodilation resulting in the increase of blood and oxygen supplies to muscles. Little is known about the biotransformation and elimination of RLX in horses. This paper describes an administration study of rhRLX-2 and its elimination in horses, and the development of sensitive methods for the detection and confirmation of rhRLX-2 in both horse plasma and urine by nano-liquid chromatography/high resolution mass spectrometry (nano-LC/HRMS) after immunoaffinity extraction with the objective of controlling the abuse of rhRLX-2 in horses. The limits of detection in plasma and urine are 2 pg/mL and 5 pg/mL, respectively. Two thoroughbred geldings were each administered one dose of 10 mg rhRLX-2 subcutaneously daily for 3 consecutive days. The rhRLX-2 could be detected and confirmed in the plasma and urine samples collected 105 h and 80 h, respectively, after the last dose of administration. For doping control purposes, rhRLX-2 ELISA could be used as a screening test to identify potential positive samples for further investigation using the nano-LC/HRMS methods.
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Affiliation(s)
- Wai Him Kwok
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, N.T., Hong Kong, China
| | - Timmy L S Choi
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, N.T., Hong Kong, China
| | - Gary N W Leung
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, N.T., Hong Kong, China
| | - April S Y Wong
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, N.T., Hong Kong, China
| | | | - Terence S M Wan
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, N.T., Hong Kong, China
| | - Emmie N M Ho
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, N.T., Hong Kong, China
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6
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Carillon J, Saby M, Barial S, Sansone A, Scanferlato R, Gayrard N, Lajoix AD, Jover B, Chatgilialoglu C, Ferreri C. Melon juice concentrate supplementation in an animal model of obesity: Involvement of relaxin and fatty acid pathways. J Funct Foods 2019. [DOI: 10.1016/j.jff.2019.05.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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7
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Wang E, He X, Zeng M. The Role of S1P and the Related Signaling Pathway in the Development of Tissue Fibrosis. Front Pharmacol 2019; 9:1504. [PMID: 30687087 PMCID: PMC6338044 DOI: 10.3389/fphar.2018.01504] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 12/10/2018] [Indexed: 12/12/2022] Open
Abstract
Tissue fibrosis, including pulmonary fibrosis, hepatic fibrosis, and cardiac fibrosis, is an important stage in the development of many diseases. It can lead to structural damage and dysfunction and even severe carcinogenesis or death. There is currently no effective method for the treatment of fibrosis. At present, the molecular mechanism of tissue fibrosis has not yet been fully elucidated, but many studies have demonstrated that it is involved in conveying the complex messages between fibroblasts and various cytokines. Sphingosine 1-phosphate (S1P) is a naturally bioactive sphingolipid. S1P and the related signaling pathways are important intracellular metabolic pathways involved in many life activities, including cell proliferation, differentiation, apoptosis, and cellular signal transduction. Increasing evidence suggests that S1P and its signaling pathways play an important role in the development of tissue fibrosis; however, the mechanisms of these effects have not yet been fully elucidated, and even the role of S1P and its signaling pathways are still controversial. This article focuses on the role of S1P and the related signaling pathways in the development of fibrosis of lung, liver, heart, and other tissues, with emphasis on the application of inhibitors of some of molecules in the pathway in clinical treatment of fibrosis diseases.
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Affiliation(s)
- Erjin Wang
- Department of Health Toxicology, Xiangya School of Public Health, Central South University, Changsha, China
| | - Xingxuan He
- Department of Human Genetics and Genomic Sciences, Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Ming Zeng
- Department of Health Toxicology, Xiangya School of Public Health, Central South University, Changsha, China
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8
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Wrobel MH. Do chlorinated insecticides (aldrin and DDT) or products of their transformations (dieldrin and DDE) impair signal transfer from regulators (oxytocin and relaxin) of bovine myometrium motility in vitro? ENVIRONMENTAL RESEARCH 2018; 167:234-239. [PMID: 30059857 DOI: 10.1016/j.envres.2018.07.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/10/2018] [Accepted: 07/17/2018] [Indexed: 06/08/2023]
Abstract
Aldrin, dieldrin, and DDT are chlorinated insecticides that are unintentionally widespread in the environment. It was previously shown that all of the aforementioned compounds increased secretion of ovarian oxytocin (OT), which is a potent uterotonic agent. However, only DDT and its metabolite (DDE) promoted, while aldrin and dieldrin inhibited basal and OT-stimulated myometrial contractions in cows. Therefore, the aim of this study was to determine the effect of these treatments on the reception and further transmission of the OT-signal for myometrial contractions and on the levels of contractile-associated integral proteins (caveolin; CAV) and gap junction proteins (GAPs). Moreover, their effect on reception of signal for the relaxation of myometrium was also studied. Myometrial strips or cells from non-pregnant (8-12 days of oestrous cycle) or late pregnant (5-8 months) cows were incubated with the studied compounds at environmentally relevant dose (10 ng/ml), which was chosen according to the previous studies. DDT and DDE increased the CAV protein level, while dieldrin decreased the GAPs level. None of the studied compounds affected mRNA expression of the OT receptor and expression of the second messengers (DAG, IP3, PKC, MLCK). Oppositely, DDE and dieldrin decreased mRNA expression of the relaxin (RLX) receptor. Changes in the amount of contractile-associated integral proteins may be involved in the molecular mechanism underlying the adverse effects of the studied insecticides on myometrial motility. Admittedly, none of the studied compounds impaired the reception or further intracellular transmission of the OT signal to promote contractions during the oestrous cycle, while they showed potential to impair the transmission the signal between cells as well as to diminish the effects of one of the primary inhibitor (RLX) of myometrial contractions during gestation.
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Affiliation(s)
- Michal Hubert Wrobel
- Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Tuwima Street 10, 10-748 Olsztyn, Poland.
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9
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Lian X, Beer-Hammer S, König GM, Kostenis E, Nürnberg B, Gollasch M. RXFP1 Receptor Activation by Relaxin-2 Induces Vascular Relaxation in Mice via a Gα i2-Protein/PI3Kß/γ/Nitric Oxide-Coupled Pathway. Front Physiol 2018; 9:1234. [PMID: 30233409 PMCID: PMC6131674 DOI: 10.3389/fphys.2018.01234] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Accepted: 08/15/2018] [Indexed: 01/10/2023] Open
Abstract
Background: Relaxins are small peptide hormones, which are novel candidate molecules that play important roles in cardiometablic syndrome. Relaxins are structurally related to the insulin hormone superfamily, which provide vasodilatory effects by activation of G-protein-coupled relaxin receptors (RXFPs) and stimulation of endogenous nitric oxide (NO) generation. Recently, relaxin could be demonstrated to activate Gi proteins and phosphoinositide 3-kinase (PI3K) pathways in cultured endothelial cells in vitro. However, the contribution of the Gi-PI3K pathway and their individual components in relaxin-dependent relaxation of intact arteries remains elusive. Methods: We used Gαi2- (Gnai2-/-) and Gαi3-deficient (Gnai3-/-) mice, pharmacological tools and wire myography to study G-protein-coupled signaling pathways involved in relaxation of mouse isolated mesenteric arteries by relaxins. Human relaxin-1, relaxin-2, and relaxin-3 were tested. Results: Relaxin-2 (∼50% relaxation at 10-11 M) was the most potent vasodilatory relaxin in mouse mesenteric arteries, compared to relaxin-1 and relaxin-3. The vasodilatory effects of relaxin-2 were inhibited by removal of the endothelium or treatment of the vessels with N (G)-nitro-L-arginine methyl ester (L-NAME, endothelial nitric oxide synthase (eNOS) inhibitor) or simazine (RXFP1 inhibitor). The vasodilatory effects of relaxin-2 were absent in arteries of mice treated with pertussis toxin (PTX). They were also absent in arteries isolated from Gnai2-/- mice, but not from Gnai3-/- mice. The effects were not affected by FR900359 (Gαq protein inhibitor) or PI-103 (PI3Kα inhibitor), but inhibited by TGX-221 (PI3Kβ inhibitor) or AS-252424 (PI3Kγ inhibitor). Simazine did not influence the anti-contractile effect of perivascular adipose tissue. Conclusion: Our data indicate that relaxin-2 produces endothelium- and NO-dependent relaxation of mouse mesenteric arteries by activation of RXFP1 coupled to Gi2-PI3K-eNOS pathway. Targeting vasodilatory Gi-protein-coupled RXFP1 pathways may provide promising opportunities for drug discovery in endothelial dysfunction and cardiometabolic disease.
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Affiliation(s)
- Xiaoming Lian
- Experimental and Clinical Research Center (ECRC), Charité - University Medicine Berlin and Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Sandra Beer-Hammer
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research (ICePhA), Tübingen, Germany
| | - Gabriele M König
- Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Evi Kostenis
- Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Bernd Nürnberg
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research (ICePhA), Tübingen, Germany
| | - Maik Gollasch
- Experimental and Clinical Research Center (ECRC), Charité - University Medicine Berlin and Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Medical Clinic for Nephrology and Internal Intensive Care, Charité Campus Virchow Klinikum, Berlin, Germany
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10
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You X, Guo ZF, Cheng F, Yi B, Yang F, Liu X, Zhu N, Zhao X, Yan G, Ma XL, Sun J. Transcriptional up-regulation of relaxin-3 by Nur77 attenuates β-adrenergic agonist-induced apoptosis in cardiomyocytes. J Biol Chem 2018; 293:14001-14011. [PMID: 30006349 DOI: 10.1074/jbc.ra118.003099] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 07/12/2018] [Indexed: 12/28/2022] Open
Abstract
The relaxin family peptides have been shown to exert several beneficial effects on the heart, including anti-apoptosis, anti-fibrosis, and anti-hypertrophy activity. Understanding their regulation might provide new opportunities for therapeutic interventions, but the molecular mechanism(s) coordinating relaxin expression in the heart remain largely obscured. Previous work demonstrated a role for the orphan nuclear receptor Nur77 in regulating cardiomyocyte apoptosis. We therefore investigated Nur77 in the hopes of identifying novel relaxin regulators. Quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) data indicated that ectopic expression of orphan nuclear receptor Nur77 markedly increased the expression of latexin-3 (RLN3), but not relaxin-1 (RLN1), in neonatal rat ventricular cardiomyocytes (NRVMs). Furthermore, we found that the β-adrenergic agonist isoproterenol (ISO) markedly stimulated RLN3 expression, and this stimulation was significantly attenuated in Nur77 knockdown cardiomyocytes and Nur77 knockout hearts. We showed that Nur77 significantly increased RLN3 promoter activity via specific binding to the RLN3 promoter, as demonstrated by electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assays. Furthermore, we found that Nur77 overexpression potently inhibited ISO-induced cardiomyocyte apoptosis, whereas this protective effect was significantly attenuated in RLN3 knockdown cardiomyocytes, suggesting that Nur77-induced RLN3 expression is an important mediator for the suppression of cardiomyocyte apoptosis. These findings show that Nur77 regulates RLN3 expression, therefore suppressing apoptosis in the heart, and suggest that activation of Nur77 may represent a useful therapeutic strategy for inhibition of cardiac fibrosis and heart failure.
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Affiliation(s)
- Xiaohua You
- From the Department of Cardiology, Changhai Hospital, Second Military Medical University, Shanghai 200433, China.,the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Zhi-Fu Guo
- From the Department of Cardiology, Changhai Hospital, Second Military Medical University, Shanghai 200433, China.,the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Fang Cheng
- the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Bing Yi
- the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Fan Yang
- the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Xinzhu Liu
- the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Ni Zhu
- From the Department of Cardiology, Changhai Hospital, Second Military Medical University, Shanghai 200433, China
| | - Xianxian Zhao
- From the Department of Cardiology, Changhai Hospital, Second Military Medical University, Shanghai 200433, China
| | - Guijun Yan
- the Reproductive Medicine Center, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 211166, China
| | - Xin-Liang Ma
- the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Jianxin Sun
- From the Department of Cardiology, Changhai Hospital, Second Military Medical University, Shanghai 200433, China, .,the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
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11
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Vestri A, Pierucci F, Frati A, Monaco L, Meacci E. Sphingosine 1-Phosphate Receptors: Do They Have a Therapeutic Potential in Cardiac Fibrosis? Front Pharmacol 2017. [PMID: 28626422 PMCID: PMC5454082 DOI: 10.3389/fphar.2017.00296] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Sphingosine 1-phosphate (S1P) is a bioactive lipid that is characterized by a peculiar mechanism of action. In fact, S1P, which is produced inside the cell, can act as an intracellular mediator, whereas after its export outside the cell, it can act as ligand of specific G-protein coupled receptors, which were initially named endothelial differentiation gene (Edg) and eventually renamed sphingosine 1-phosphate receptors (S1PRs). Among the five S1PR subtypes, S1PR1, S1PR2 and S1PR3 isoforms show broad tissue gene expression, while S1PR4 is primarily expressed in immune system cells, and S1PR5 is expressed in the central nervous system. There is accumulating evidence for the important role of S1P as a mediator of many processes, such as angiogenesis, carcinogenesis and immunity, and, ultimately, fibrosis. After a tissue injury, the imbalance between the production of extracellular matrix (ECM) and its degradation, which occurs due to chronic inflammatory conditions, leads to an accumulation of ECM and, consequential, organ dysfunction. In these pathological conditions, many factors have been described to act as pro- and anti-fibrotic agents, including S1P. This bioactive lipid exhibits both pro- and anti-fibrotic effects, depending on its site of action. In this review, after a brief description of sphingolipid metabolism and signaling, we emphasize the involvement of the S1P/S1PR axis and the downstream signaling pathways in the development of fibrosis. The current knowledge of the therapeutic potential of S1PR subtype modulators in the treatment of the cardiac functions and fibrinogenesis are also examined.
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Affiliation(s)
- Ambra Vestri
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Molecular and Applied Biology Research Unit, University of FlorenceFlorence, Italy
| | - Federica Pierucci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Molecular and Applied Biology Research Unit, University of FlorenceFlorence, Italy.,Interuniversity Institutes of MyologyFirenze, Italy
| | - Alessia Frati
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Molecular and Applied Biology Research Unit, University of FlorenceFlorence, Italy
| | - Lucia Monaco
- Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of RomeRome, Italy
| | - Elisabetta Meacci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Molecular and Applied Biology Research Unit, University of FlorenceFlorence, Italy.,Interuniversity Institutes of MyologyFirenze, Italy
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12
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Zhang C, Baimoukhametova DV, Smith CM, Bains JS, Gundlach AL. Relaxin-3/RXFP3 signalling in mouse hypothalamus: no effect of RXFP3 activation on corticosterone, despite reduced presynaptic excitatory input onto paraventricular CRH neurons in vitro. Psychopharmacology (Berl) 2017; 234:1725-1739. [PMID: 28314951 DOI: 10.1007/s00213-017-4575-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 02/16/2017] [Indexed: 02/06/2023]
Abstract
Relaxin-3/RXFP3 signalling is proposed to be involved in the neuromodulatory control of arousal- and stress-related neural circuits. Furthermore, previous studies in rats have led to the proposal that relaxin-3/RXFP3 signalling is associated with activation of the hypothalamic-pituitary-adrenal axis, but direct evidence for RXFP3-related actions on the activity of hypothalamic corticotropin-releasing hormone (CRH) neurons is lacking. In this study, we investigated characteristics of the relaxin-3/RXFP3 system in mouse hypothalamus. Administration of an RXFP3 agonist (RXFP3-A2) intra-cerebroventricularly or directly into the paraventricular nucleus of hypothalamus (PVN) of C57BL/6J mice did not alter corticosterone levels. Similarly, there were no differences between serum corticosterone levels in Rxfp3 knockout (C57BL/6JRXFP3TM1) and wild-type mice at baseline and after stress, despite detection of the predicted stress-induced increases in serum corticosterone. We examined the nature of the relaxin-3 innervation of PVN in wild-type mice and in Crh-IRES-Cre;Ai14 mice that co-express the tdTomato fluorophore in CRH neurons, identifying abundant relaxin-3 fibres in the peri-PVN region, but only sparse fibres associated with densely packed CRH neurons. In whole-cell voltage-clamp recordings of tdTomato-positive CRH neurons in these mice, we observed a reduction in sEPSC frequency following local application of RXFP3-A2, consistent with an activation of RXFP3 on presynaptic glutamatergic afferents in the PVN region. These studies clarify the relationship between relaxin-3/RXFP3 inputs and CRH neurons in mouse PVN, with implications for the interpretation of current and previous in vivo studies and future investigations of this stress-related signalling network in normal and transgenic mice, under normal and pathological conditions.
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Affiliation(s)
- C Zhang
- The Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, VIC, 3052, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - D V Baimoukhametova
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - C M Smith
- The Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, VIC, 3052, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - J S Bains
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Andrew L Gundlach
- The Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, VIC, 3052, Australia. .,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, 3010, Australia.
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13
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Relaxin Attenuates Contrast-Induced Human Proximal Tubular Epithelial Cell Apoptosis by Activation of the PI3K/Akt Signaling Pathway In Vitro. BIOMED RESEARCH INTERNATIONAL 2017; 2017:2869405. [PMID: 28540295 PMCID: PMC5429925 DOI: 10.1155/2017/2869405] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 03/22/2017] [Accepted: 03/26/2017] [Indexed: 12/29/2022]
Abstract
Background. Contrast-induced acute kidney injury (CI-AKI) is one of the main causes of iatrogenic acute kidney injury (AKI); however, therapeutic strategies for AKI remain limited. This study aims to explore the effect of relaxin (RLX) on contrast-induced HK-2 apoptosis and its underlying mechanisms. Methods. Renal tubular epithelial cells (HK-2) were incubated either with or without ioversol, human H2 relaxin, and LY294002 (the inhibitor of the PI3K/Akt signal pathway). Cell viability was evaluated with a CCK-8 assay. Apoptotic morphologic alterations were observed using the Hoechst 33342 staining method. Apoptosis was detected with Annexin V staining. Western blot analysis was employed to measure the expression of pAkt (S473), Akt, cleaved caspase-3, Bcl-2, Bax, and actin proteins. Results. Ioversol reduced the viability of HK-2 cells. Western blotting results revealed decreased expression of phosphorylated Akt in cells treated with ioversol. The activities of caspase-3 and Bax protein increased, while the expression of Bcl-2 protein decreased. As a result, the Bax/Bcl-2 ratio increased after treatment with ioversol. These effects were reversed when HK-2 cells were cotreated with RLX. However, with preadministration of PI3K/Akt pathway inhibitor LY294002, the effect of RLX was blocked. Conclusion. Our study demonstrates that relaxin attenuates ioversol induced cell apoptosis via activation of the PI3K/Akt signaling pathway, suggesting that RLX might play a protective role in the treatment of CI-AKI.
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14
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Kang YM, Lee HM, Moon SH, Kang H, Choi YR. Relaxin Modulates the Expression of MMPs and TIMPs in Fibroblasts of Patients with Carpal Tunnel Syndrome. Yonsei Med J 2017; 58:415-422. [PMID: 28120574 PMCID: PMC5290023 DOI: 10.3349/ymj.2017.58.2.415] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/02/2016] [Accepted: 11/10/2016] [Indexed: 11/27/2022] Open
Abstract
PURPOSE The aim of this study was to investigate the anti-fibrotic effect of relaxin in subsynovial fibroblasts activated by transforming growth factor beta (TGF-β). MATERIALS AND METHODS To test the anti-fibrotic effect of an adenovirus-relaxin construct (Ad-RLN) on subsynovial fibroblasts in vitro, cells from subsynovial connective tissue of patients with carpal tunnel syndrome were activated with TGF-β1 and exposed to Ad-RLN (as a therapeutic gene) or adenovirus-lacZ construct (as a marker gene) for four hours. Subsynovial fibroblast cultures without adenoviral exposure served as controls. RESULTS We observed induction of gene expressions of collagen I, III and IV, as well as the abatement of alpha-smooth muscle actin (a-SMA) synthesis, Smad2 phosphorylation, and fibronectin at the protein level, in comparison to controls. In addition, protein expressions of matrix metalloproteinase (MMP) I was significantly induced, whereas the protein expressions of tissue inhibitor of metalloproteinases (TIMP) I and IV were reduced due to relaxin expression. CONCLUSION RLN prevents excessive synthesis of extracellular matrix by reducing the expressions of its components, such as fibronectin, a-SMA, and phosphorylated Smad2, by increasing the expression of MMPs; and by decreasing the expression of TIMPs.
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Affiliation(s)
- Young Mi Kang
- BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Hwan Mo Lee
- Department of Orthopedic Surgery, Yonsei University College of Medicine, Seoul, Korea
| | - Seong Hwan Moon
- BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
- Department of Orthopedic Surgery, Yonsei University College of Medicine, Seoul, Korea
| | - Ho Kang
- Department of Orthopedic Surgery, Yonsei University College of Medicine, Seoul, Korea
| | - Yun Rak Choi
- Department of Orthopedic Surgery, Yonsei University College of Medicine, Seoul, Korea.
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15
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Tyler JM, Pang PS, Teerlink JR. Serelaxin in the Treatment of Acute Heart Failure. CURRENT EMERGENCY AND HOSPITAL MEDICINE REPORTS 2016. [DOI: 10.1007/s40138-016-0114-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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16
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Jelinic M, Kahlberg N, Parry LJ, Tare M. Does serelaxin treatment alter passive mechanical wall properties in small resistance arteries? Microcirculation 2016; 23:631-636. [DOI: 10.1111/micc.12321] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 09/15/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Maria Jelinic
- School of BioSciences; The University of Melbourne; Parkville Victoria Australia
| | - Nicola Kahlberg
- School of BioSciences; The University of Melbourne; Parkville Victoria Australia
| | - Laura J. Parry
- School of BioSciences; The University of Melbourne; Parkville Victoria Australia
| | - Marianne Tare
- Department of Physiology; Monash University; Parkville Victoria Australia
- School of Rural Health; Monash University; Parkville Victoria Australia
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17
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Frati A, Ricci B, Pierucci F, Nistri S, Bani D, Meacci E. Role of sphingosine kinase/S1P axis in ECM remodeling of cardiac cells elicited by relaxin. Mol Endocrinol 2016; 29:53-67. [PMID: 25415609 DOI: 10.1210/me.2014-1201] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The initiation and progression of heart failure is linked to adverse cardiac remodeling of the extracellular matrix (ECM) during disease mainly through the deregulation of myocardial metalloproteinases (MMPs). Relaxin (RLX), a peptide hormone acting as a physiological cardiac effector, is a key regulator of ECM remodeling in reproductive and nonreproductive tissues. Studying primary cultures of mouse cardiac muscle cells and rat H9c2 cardiomyoblasts, we have obtained evidence for a new signaling pathway activated by RLX to induce ECM remodeling that involves the bioactive sphingolipids sphingosine-1-phosphate (S1P) and ceramide. In both cell populations, recombinant human RLX increased sphingosine kinase activity and S1P formation, whereas sphingomyelin and ceramide content were decreased in [(3)H]serine-labeled cells. According to the literature, RLX promoted MMP-2 and MMP-9 expression/release. Pharmacological inhibition of sphingolipid metabolism and silencing of sphingosine kinase 1, the enzyme responsible for S1P formation, were able to prevent MMP expression/release elicited by the hormone and induce the expression of tissue inhibitor of MMPs. In addition, we found that sphingolipid signaling is required for the regulation of connective tissue growth factor, a member of the CCN 1-3 family of genes that are involved in cell proliferation and differentiation. Finally, the induction of cardiomyoblast maturation induced by RLX was also found to be counteracted by inhibition of S1P formation. In conclusion, these findings provide a novel mechanism by which RLX acts on cardiac ECM remodeling and cardiac cell differentiation and offer interesting therapeutic options to prevent heart fibrosis and to favor myocardial regeneration.
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Affiliation(s)
- Alessia Frati
- Department of Biomedical, Experimental, and Clinical Sciences (A.F., B.R., F.P., E.M.), Research Unit of Biochemistry, and Department of Experimental and Clinical Medicine (S.N., D.B.), Research Unit of Histology and Embryology, University of Florence, 50134 Florence, Italy
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18
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Hossain MA, Kocan M, Yao ST, Royce SG, Nair VB, Siwek C, Patil NA, Harrison IP, Rosengren KJ, Selemidis S, Summers RJ, Wade JD, Bathgate RAD, Samuel CS. A single-chain derivative of the relaxin hormone is a functionally selective agonist of the G protein-coupled receptor, RXFP1. Chem Sci 2016; 7:3805-3819. [PMID: 30155023 PMCID: PMC6013806 DOI: 10.1039/c5sc04754d] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/24/2016] [Indexed: 11/24/2022] Open
Abstract
A single-chain derivative of the relaxin hormone ameliorates fibrosis without side-effects.
Human gene-2 relaxin (H2 relaxin) is a pleiotropic hormone with powerful vasodilatory and anti-fibrotic properties which has led to its clinical evaluation and provisional FDA approval as a treatment for acute heart failure. The diverse effects of H2 relaxin are mediated via its cognate G protein coupled-receptor (GPCR), Relaxin Family Peptide Receptor (RXFP1), leading to stimulation of a combination of cell signalling pathways that includes cyclic adenosine monophosphate (cAMP) and extracellular-signal-regulated kinases (ERK)1/2. However, its complex two-chain (A and B), disulfide-rich insulin-like structure is a limitation to its facile preparation, availability and affordability. Furthermore, its strong activation of cAMP signaling is likely responsible for reported detrimental tumor-promoting actions that may preclude long-term use of this drug for treating human disease. Here we report the design and synthesis of a H2 relaxin B-chain-only analogue, B7-33, which was shown to bind to RXFP1 and preferentially activate the pERK pathway over cAMP in cells that endogenously expressed RXFP1. Thus, B7-33 represents the first functionally selective agonist of the complex GPCR, RXFP1. Importantly, this small peptide agonist prevented or reversed organ fibrosis and dysfunction in three pre-clinical rodent models of heart or lung disease with similar potency to H2 relaxin. The molecular mechanism behind the strong anti-fibrotic actions of B7-33 involved its activation of RXFP1-angiotensin II type 2 receptor heterodimers that induced selective downstream signaling of pERK1/2 and the collagen-degrading enzyme, matrix metalloproteinase (MMP)-2. Furthermore, in contrast to H2 relaxin, B7-33 did not promote prostate tumor growth in vivo. Our results represent the first known example of the minimisation of a two-chain cyclic insulin-like peptide to a single-chain linear peptide that retains potent beneficial agonistic effects.
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Affiliation(s)
- Mohammed Akhter Hossain
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Victoria 3010 , Australia . ; ; .,School of Chemistry , The University of Melbourne , Victoria 3010 , Australia
| | - Martina Kocan
- Monash Institute of Pharmaceutical Sciences , Monash University , Victoria , Australia
| | - Song T Yao
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Victoria 3010 , Australia . ; ;
| | - Simon G Royce
- Cardiovascular Disease Program , Biomedicine Discovery Institute and Department of Pharmacology , Monash University , Victoria , Australia .
| | - Vinojini B Nair
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Victoria 3010 , Australia . ; ; .,School of Chemistry , The University of Melbourne , Victoria 3010 , Australia
| | - Christopher Siwek
- Monash Institute of Pharmaceutical Sciences , Monash University , Victoria , Australia
| | - Nitin A Patil
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Victoria 3010 , Australia . ; ; .,School of Chemistry , The University of Melbourne , Victoria 3010 , Australia
| | - Ian P Harrison
- Cardiovascular Disease Program , Biomedicine Discovery Institute and Department of Pharmacology , Monash University , Victoria , Australia .
| | - K Johan Rosengren
- The University of Queensland , School of Biomedical Sciences , Brisbane , QLD 4072 , Australia
| | - Stavros Selemidis
- Cardiovascular Disease Program , Biomedicine Discovery Institute and Department of Pharmacology , Monash University , Victoria , Australia .
| | - Roger J Summers
- Monash Institute of Pharmaceutical Sciences , Monash University , Victoria , Australia
| | - John D Wade
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Victoria 3010 , Australia . ; ; .,School of Chemistry , The University of Melbourne , Victoria 3010 , Australia
| | - Ross A D Bathgate
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Victoria 3010 , Australia . ; ; .,Department of Biochemistry , The University of Melbourne , Victoria 3010 , Australia
| | - Chrishan S Samuel
- Cardiovascular Disease Program , Biomedicine Discovery Institute and Department of Pharmacology , Monash University , Victoria , Australia .
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19
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Kumar JR, Rajkumar R, Farooq U, Lee LC, Tan FCK, Dawe GS. Evidence of D2 receptor expression in the nucleus incertus of the rat. Physiol Behav 2015; 151:525-34. [PMID: 26300469 DOI: 10.1016/j.physbeh.2015.08.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 07/27/2015] [Accepted: 08/17/2015] [Indexed: 01/11/2023]
Abstract
The nucleus incertus (NI), located in the caudal brainstem, mainly consists of GABAergic neurons with widespread projections across the brain. It is the chief source of relaxin-3 in the mammalian brain and densely expresses corticotropin-releasing factor type 1 (CRF1) receptors. Several other neurotransmitters, peptides and receptors are reportedly expressed in the NI. In the present investigation, we show the expression of dopamine type-2 (D2) receptors in the NI by reverse transcriptase-polymerase chain reaction (RT-PCR), western blotting (WB) and immunofluorescence (IF). RT-PCR did not show expression of D3 receptors. D2 receptor short isoform (D2S)-like, relaxin-3, CRF1/2 receptor and NeuN immunoreactivity were co-expressed in the cells of the NI. Behavioural effects of D2 receptor activation by intra-NI infusion of quinpirole (a D2/D3 agonist) were evaluated. Hypolocomotion was observed in home cage monitoring system (LABORAS) and novel environment-induced suppression of feeding behavioural paradigms. Thus the D2 receptors expressed in the NI are likely to play a role in locomotion. Based on its strong bidirectional connections to the median raphe and interpeduncular nuclei, the NI was predicted to play a role in modulating behavioural activity and the present results lend support to this hypothesis. This is the first evidence of expression of a catecholamine receptor, D2-like immunoreactivity, in the NI.
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Affiliation(s)
- Jigna Rajesh Kumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456, Singapore
| | - Ramamoorthy Rajkumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore
| | - Usman Farooq
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore
| | - Liying Corinne Lee
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore
| | - Francis Chee Kuan Tan
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore
| | - Gavin S Dawe
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456, Singapore.
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20
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Haugaard-Kedström LM, Hossain MA, Daly NL, Bathgate RAD, Rinderknecht E, Wade JD, Craik DJ, Rosengren KJ. Solution structure, aggregation behavior, and flexibility of human relaxin-2. ACS Chem Biol 2015; 10:891-900. [PMID: 25547165 DOI: 10.1021/cb500918v] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Relaxin is a member of the relaxin/insulin peptide hormone superfamily and is characterized by a two-chain structure constrained by three disulfide bonds. Relaxin is a pleiotropic hormone and involved in a number of physiological and pathogenic processes, including collagen and cardiovascular regulation and tissue remodelling during pregnancy and cancer. Crystallographic and ultracentrifugation experiments have revealed that the human form of relaxin, H2 relaxin, self-associates into dimers, but the significance of this is poorly understood. Here, we present the NMR structure of a monomeric, amidated form of H2 relaxin and compare its features and behavior in solution to those of native H2 relaxin. The overall structure of H2 relaxin is retained in the monomeric form. H2 relaxin amide is fully active at the relaxin receptor RXFP1 and thus dimerization is not required for biological activity. Analysis of NMR chemical shifts and relaxation parameters identified internal motion in H2 relaxin at the pico-nanosecond and milli-microsecond time scales, which is commonly seen in other relaxin and insulin peptides and might be related to function.
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Affiliation(s)
| | | | - Norelle L. Daly
- Centre for
Biodiscovery and Molecular Development of Therapeutics, AITHM, James Cook University, Cairns, Queensland 4878, Australia
| | | | - Ernst Rinderknecht
- Corthera, c/o
Novartis Corporation, San Carlos, California 94070, United States
| | | | | | - K. Johan Rosengren
- School
of Natural Sciences, Linnaeus University, SE-391 82 Kalmar, Sweden
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21
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Wilson SS, Ayaz SI, Levy PD. Relaxin: A Novel Agent for the Treatment of Acute Heart Failure. Pharmacotherapy 2015; 35:315-27. [DOI: 10.1002/phar.1548] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Suprat S. Wilson
- Department of Pharmacy; Detroit Receiving Hospital; Detroit Michigan
| | - Syed I. Ayaz
- Department of Emergency Medicine; Wayne State University School of Medicine; Detroit Michigan
| | - Phillip D. Levy
- Department of Emergency Medicine; Cardiovascular Research Institute; Wayne State University School of Medicine; Detroit Michigan
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22
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Guo YQ, Wu QP, Shao XX, Shen T, Liu YL, Xu ZG, Guo ZY. Secretory overexpression and isotopic labeling of the chimeric relaxin family peptide R3/I5 in Pichia pastoris. Amino Acids 2015; 47:1117-25. [DOI: 10.1007/s00726-015-1939-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 02/09/2015] [Indexed: 11/25/2022]
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23
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Yegorov S, Bogerd J, Good SV. The relaxin family peptide receptors and their ligands: new developments and paradigms in the evolution from jawless fish to mammals. Gen Comp Endocrinol 2014; 209:93-105. [PMID: 25079565 DOI: 10.1016/j.ygcen.2014.07.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Revised: 07/01/2014] [Accepted: 07/16/2014] [Indexed: 12/13/2022]
Abstract
Relaxin family peptide receptors (Rxfps) and their ligands, relaxin (Rln) and insulin-like (Insl) peptides, are broadly implicated in the regulation of reproductive and neuroendocrine processes in mammals. Most placental mammals harbour genes for four receptors, namely rxfp1, rxfp2, rxfp3 and rxfp4. The number and identity of rxfps in other vertebrates are immensely variable, which is probably attributable to intraspecific variation in reproductive and neuroendocrine regulation. Here, we highlight several interesting, but greatly overlooked, aspects of the rln/insl-rxfp evolutionary history: the ancient origin, recruitment of novel receptors, diverse roles of selection, differential retention and lineage-specific loss of genes over evolutionary time. The tremendous diversity of rln/insl and rxfp genes appears to have arisen from two divergent receptors and one ligand that were duplicated by whole genome duplications (WGD) in early vertebrate evolution, although several genes, notably relaxin in mammals, were also duplicated via small scale duplications. Duplication and loss of genes have varied across lineages: teleosts retained more WGD-derived genes, dominated by those thought to be involved in neuroendocrine regulation (rln3, insl5 and rxfp 3/4 genes), while eutherian mammals witnessed the diversification and rapid evolution of genes involved in reproduction (rln/insl3). Several genes that arose early in evolutionary history were lost in most mammals, but retained in teleosts and, to a lesser extent, in early diverging tetrapods. To elaborate on their evolutionary history, we provide updated phylogenies of the Rxfp1/2 and Rxfp3/4 receptors and their ligands, including new sequences from early diverging vertebrate taxa such as coelacanth, skate, spotted gar, and lamprey. We also summarize the recent progress made towards understanding the functional biology of Rxfps in non-mammalian taxa, providing a new conceptual framework for research on Rxfp signaling across vertebrates.
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Affiliation(s)
- Sergey Yegorov
- Department of Biology, University of Winnipeg, 599 Portage Ave., Winnipeg, MB, Canada
| | - Jan Bogerd
- Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Sara V Good
- Department of Biology, University of Winnipeg, 599 Portage Ave., Winnipeg, MB, Canada.
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24
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Ma X, Han S, Zhang W, Fan YJ, Liu MN, Liu AY, Liu BR. Protection of cultured human hepatocytes from hydrogen peroxide‑induced apoptosis by relaxin‑3. Mol Med Rep 2014; 11:1228-34. [PMID: 25370004 DOI: 10.3892/mmr.2014.2842] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 10/01/2014] [Indexed: 11/06/2022] Open
Abstract
Previous studies have suggested that hepatocyte apoptosis may be a fundamental underlying mechanism of liver injury and diseases, such as liver fibrosis. Relaxin‑3 has been reported to have anti‑fibrotic actions in the heart and to attenuate isoproterenol‑induced myocardial injury; however, the beneficial role of relaxin‑3 on hepatocyte apoptosis remains to be elucidated. The aim of the present study was to explore the role and possible mechanisms of relaxin‑3 through hydrogen peroxide (H2O2)‑induced apoptosis in primary human hepatocytes. Cells were treated with relaxin‑3 and then cell viability, morphological features, the presence of cleaved caspases as well as the levels of endoplasmic reticulum stress (ERS) protein markers and autophagy markers were evaluated. The H2O2 group showed significantly decreased cell viability, increased apoptosis as well as upregulation of caspases (cleaved caspase‑3, ‑8 and ‑9) and ERS protein markers compared with those of the control group. However, cells treated with relaxin‑3 (10 ng/ml) demonstrated improved cell viability, reduced apoptosis and decreased expression of cleaved caspases and ERS markers. However, the expression of autophagy markers remained unchanged following H2O2‑induced apoptosis and relaxin‑3 treatment. In conclusion, relaxin‑3 was shown to protect hepatocytes from H2O2‑induced apoptosis via downregulation of cleaved caspase‑8 and ‑9, as well as inhibition of the ERS pathway.
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Affiliation(s)
- Xiao Ma
- Department of Gastroenterology and Hepatology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China
| | - Su Han
- Department of Microbiology and Parasitology, The Heilongjiang Key Laboratory of Immunity and Infection, Pathogenic Biology, Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China
| | - Wei Zhang
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
| | - Yu-Jing Fan
- Department of Gastroenterology and Hepatology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China
| | - Ming-Na Liu
- Department of Gastroenterology and Hepatology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China
| | - Ai-Yun Liu
- Department of Gastroenterology and Hepatology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China
| | - Bing-Rong Liu
- Department of Gastroenterology and Hepatology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China
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25
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Boughton CK, Murphy KG. Can neuropeptides treat obesity? A review of neuropeptides and their potential role in the treatment of obesity. Br J Pharmacol 2014; 170:1333-48. [PMID: 23121386 DOI: 10.1111/bph.12037] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 10/17/2012] [Accepted: 10/17/2012] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED Obesity is a major worldwide public health issue. The physiological systems that regulate body weight are thus of great interest as targets for anti-obesity agents. Peptidergic systems are critical to the regulation of energy homeostasis by key regions in the hypothalamus and brainstem. A number of neuropeptide systems have therefore been investigated as potential treatments for obesity. Blocking orexigenic peptide signals such as neuropeptide Y, melanin-concentrating hormone, orexins, relaxin-3 and galanin-like peptide or stimulating anorectic signalling pathways used by peptides such as the melanocortins, ciliary neurotrophic factor and brain-derived neurotrophic factor, are approaches that have shown some promise, but which have also highlighted possible concerns. Manipulation of central peptidergic systems poses a number of therapeutic problems, including brain access and side effects. Given that the homeostatic defence of body weight may limit the effectiveness of any single-target therapy developed, a combination therapy approach may offer the best hope for the effective prevention and treatment of obesity. LINKED ARTICLES This article is part of a themed section on Neuropeptides. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.170.issue-7.
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Affiliation(s)
- C K Boughton
- Section of Investigative Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
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Clifton KB, Rodner C, Wolf JM. Detection of relaxin receptor in the dorsoradial ligament, synovium, and articular cartilage of the trapeziometacarpal joint. J Orthop Res 2014; 32:1061-7. [PMID: 24797570 DOI: 10.1002/jor.22640] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/09/2014] [Indexed: 02/04/2023]
Abstract
Basilar thumb osteoarthritis (OA) is postulated to occur due to ligament attenuation of the trapeziometacarpal (TM) joint. Relaxin is a peptide hormone, which loosens ligaments before childbirth, through remodeling of the extracellular matrix via upregulation of matrix metalloproteases (MMPs). We postulated that relaxin family peptide receptor 1 (RXFP-1), the receptor for circulating relaxin, was present in tissues of the TM joint. Ligaments and synovium were sampled from 15 patients during surgery for TM arthritis. We obtained trapezial cartilage from two autopsy donors and four patients. Tissues were fixed, paraffin embedded, and sectioned at 5 µm, then were immunostained for RXFP-1, as well as MMP-1, and MMP-13, using rabbit anti-human polyclonal antibodies. Eight DRL samples showed positive immunostaining for relaxin receptor, with 14/15 positively stained in synovium. Greater staining was seen in specimens obtained from women with more severe TM arthritis. Trapezial cartilage demonstrated receptor staining within chondrocytes in the middle and deep zones. Immunostaining for MMPs co-localized with relaxin receptor staining. Relaxin receptors are present at the ligament, cartilage, and synovium of the TM joint, indicating that it is a potential target for relaxin. This suggests that circulating relaxin may impact joint stability. The role of relaxin in cartilage and synovium may be related to its role in collagen regulation as a possible tissue response to OA.
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Affiliation(s)
- Kari B Clifton
- Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, Connecticut
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Neschadim A, Summerlee AJS, Silvertown JD. Targeting the relaxin hormonal pathway in prostate cancer. Int J Cancer 2014; 137:2287-95. [PMID: 25043063 DOI: 10.1002/ijc.29079] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Accepted: 07/07/2014] [Indexed: 11/11/2022]
Abstract
Targeting the androgen signalling pathway has long been the hallmark of anti-hormonal therapy for prostate cancer. However, development of androgen-independent prostate cancer is an inevitable outcome to therapies targeting this pathway, in part, owing to the shift from cancer dependence on androgen signalling for growth in favor of augmentation of other cellular pathways that provide proliferation-, survival- and angiogenesis-promoting signals. This review focuses on the role of the hormone relaxin in the development and progression of prostate cancer, prior to and after the onset of androgen independence, as well as its role in cancers of other reproductive tissues. As the body of literature expands, examining relaxin expression in cancerous tissues and its role in a growing number of in vitro and in vivo cancer models, our understanding of the important involvement of this hormone in cancer biology is becoming clearer. Specifically, the pleiotropic functions of relaxin affecting cell growth, angiogenesis, blood flow, cell migration and extracellular matrix remodeling are examined in the context of cancer progression. The interactions and intercepts of the intracellular signalling pathways of relaxin with the androgen pathway are explored in the context of progression of castration-resistant and androgen-independent prostate cancers. We provide an overview of current anti-hormonal therapeutic treatment options for prostate cancer and delve into therapeutic approaches and development of agents aimed at specifically antagonizing relaxin signalling to curb tumor growth. We also discuss the rationale and challenges utilizing such agents as novel anti-hormonals in the clinic, and their potential to supplement current therapeutic modalities.
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Affiliation(s)
- Anton Neschadim
- Armour Therapeutics Inc., Toronto, 124 Orchard View Blvd, Toronto, ON, Canada
| | | | - Joshua D Silvertown
- Armour Therapeutics Inc., Toronto, 124 Orchard View Blvd, Toronto, ON, Canada
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Kang YM, Choi YR, Yun CO, Park JO, Suk KS, Kim HS, Park MS, Lee BH, Lee HM, Moon SH. Down-regulation of collagen synthesis and matrix metalloproteinase expression in myofibroblasts from Dupuytren nodule using adenovirus-mediated relaxin gene therapy. J Orthop Res 2014; 32:515-23. [PMID: 24293067 DOI: 10.1002/jor.22535] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 11/09/2013] [Indexed: 02/04/2023]
Abstract
Dupuytren's disease is a fibroproliferative connective tissue disorder characterized by contracture of the palmer fascia of the hand. Relaxin (RLN) is a multifunctional factor which contributes to the remodeling of the pelvic ligament by inhibiting fibrosis and inflammatory activities. The aim of this study was to investigate the effect of the RLN gene on the inhibition of fibrosis in myofibroblastic cells. Myofibroblast cells with adenovirus LacZ (Ad-LacZ) as a marker gene or adenovirus relaxin (Ad-RLN) as therapeutic gene showed transgene expressions in beta-galactosidase assay and Western blot analysis. Myofibroblastic cells with Ad-RLN demonstrated a 22% and 48% reduction in collagen I and III mRNA expressions respectively, a 50% decrease in MMP-1, 70% decrease in MMP-2, 80% decrease in MMP-9, and a 15% reduction in MMP-13 protein expression compared with cultures with viral control and saline control. In addition, myofibroblastic cells with Ad-RLN showed a 40% decrease in TIMP 1 and a 15% increase in TIMP 3 protein expression at 48 h compared to cultures with viral control and saline control. Also, myofibroblastic cell with Ad-RLN demonstrated a 74% inhibition of fibronectin and a 52% decrease in total collagen synthesis at 48 h compared with cultures with viral control and saline control. In conclusion, the RLN gene render antifibrogenic effect on myofibroblastic cells from Dupuytren's nodule via direct inhibition of collagen synthesis not through collagenolytic pathway such as MMP-1, -13, TIMP 1, and 3. Therefore relaxin can be an alternative therapeutic strategy in initial stage of Dupuytren's disease by its antifibrogenic effect.
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Affiliation(s)
- Young-Mi Kang
- BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of, Korea
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Lee LC, Rajkumar R, Dawe GS. Selective lesioning of nucleus incertus with corticotropin releasing factor-saporin conjugate. Brain Res 2013; 1543:179-90. [PMID: 24287211 DOI: 10.1016/j.brainres.2013.11.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 11/06/2013] [Accepted: 11/19/2013] [Indexed: 11/19/2022]
Abstract
The nucleus incertus (NI), a brainstem nucleus found in the pontine periventricular grey, is the primary source of the neuropeptide relaxin-3 in the mammalian brain. The NI neurons have also been previously reported to express several receptors and neurotransmitters, including corticotropin releasing hormone receptor 1 (CRF₁) and gamma-aminobutyric acid (GABA). The NI projects widely to putative neural correlates of stress, anxiety, depression, feeding behaviour, arousal and cognition leading to speculation that it might be involved in several neuropsychiatric conditions. On the premise that relaxin-3 expressing neurons in the NI predominantly co-express CRF₁ receptors, a novel method for selective ablation of the rat brain NI neurons using corticotropin releasing factor (CRF)-saporin conjugate is described. In addition to a behavioural deficit in the fear conditioning paradigm, reverse transcriptase polymerase chain reaction (RT-PCR), western blotting (WB) and immunofluorescence labelling (IF) techniques were used to confirm the NI lesion. We observed a selective and significant loss of CRF₁ expressing cells, together with a consistent decrease in relaxin-3 and GAD65 expression. The significant ablation of relaxin-3 positive neurons of the NI achieved by this lesioning approach is a promising model to explore the neuropsychopharmacological implications of NI/relaxin-3 in behavioural neuroscience.
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Affiliation(s)
- Liying Corinne Lee
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, 117597, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore
| | - Ramamoorthy Rajkumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, 117597, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore
| | - Gavin Stewart Dawe
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, 117597, Singapore; Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, 117456, Singapore; Singapore Institute for Neurotechnology (SINAPSE), 117456, Singapore.
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Belgi A, Bathgate RAD, Kocan M, Patil N, Zhang S, Tregear GW, Wade JD, Hossain MA. Minimum active structure of insulin-like peptide 5. J Med Chem 2013; 56:9509-16. [PMID: 24188028 DOI: 10.1021/jm400924p] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Insulin-like peptide 5 (INSL5) is a complex two-chain peptide hormone constrained by three disulfide bonds in a pattern identical to insulin. High expression of INSL5 in the colon suggests roles in activation of colon motility and appetite control. A more recent study indicates it may have significant roles in the regulation of insulin secretion and β-cell homeostasis. This peptide thus has considerable potential for the treatment of eating disorders, obesity, and/or diabetes. However, the synthesis of INSL5 is extremely challenging either by chemical or recombinant means. The A-chain is very poorly soluble and the B-chain is highly aggregating in nature which, together, makes their postsynthesis handling and purification very difficult. Given these difficulties, we have developed a highly active INSL5 analogue that has a much simpler structure with two disulfide bonds and is thus easier to assemble compared to native INSL5. This minimized peptide represents an attractive new mimetic for investigating the functional role of INSL5.
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Affiliation(s)
- Alessia Belgi
- Florey Institute of Neuroscience and Mental Health, ‡Department of Biochemistry and Molecular Biology, §Florey Department of Neuroscience and Mental Health, and ∥School of Chemistry, The University of Melbourne , Victoria 3010, Australia
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Farooq U, Rajkumar R, Sukumaran S, Wu Y, Tan WH, Dawe GS. Corticotropin-releasing factor infusion into nucleus incertus suppresses medial prefrontal cortical activity and hippocampo-medial prefrontal cortical long-term potentiation. Eur J Neurosci 2013; 38:2516-25. [PMID: 23668693 DOI: 10.1111/ejn.12242] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Revised: 03/14/2013] [Accepted: 04/03/2013] [Indexed: 11/30/2022]
Abstract
The medial prefrontal cortex (mPFC) in the rat has been implicated in a variety of cognitive processes, including working memory and expression of fear memory. We investigated the inputs from a brain stem nucleus, the nucleus incertus (NI), to the prelimbic area of the mPFC. This nucleus strongly expresses corticotropin-releasing factor type 1 (CRF1 ) receptors and responds to stress. A retrograde tracer was used to verify connections from the NI to the mPFC. Retrogradely labelled cells in the NI expressed CRF receptors. Electrophysiological manipulation of the NI revealed that stimulation of the NI inhibited spontaneous neuronal firing in the mPFC. Similarly, CRF infusion into the NI, in order to mimic a stressful condition, inhibited neuronal firing and burst firing in the mPFC. The effect of concurrent high-frequency stimulation of the NI on plasticity in the hippocampo-prelimbic medial prefrontal cortical (HP-mPFC) pathway was studied. It was found that electrical stimulation of the NI impaired long-term potentiation in the HP-mPFC pathway. Furthermore, CRF infusion into the NI produced similar results. These findings might account for some of the extra-pituitary functions of CRF and indicate that the NI may play a role in stress-driven modulation of working memory and possibly other cognitive processes subserved by the mPFC.
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Affiliation(s)
- Usman Farooq
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Centre for Life Sciences (CeLS), Singapore
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Zhang WJ, Jiang Q, Wang XY, Song G, Shao XX, Guo ZY. A convenient method for europium-labeling of a recombinant chimeric relaxin family peptide R3/I5 for receptor-binding assays. J Pept Sci 2013; 19:350-4. [DOI: 10.1002/psc.2507] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 02/16/2013] [Accepted: 02/21/2013] [Indexed: 11/12/2022]
Affiliation(s)
- Wei-Jie Zhang
- Institute of Protein Research, College of Life Sciences and Technology; Tongji University; Shanghai China
| | - Qian Jiang
- Institute of Protein Research, College of Life Sciences and Technology; Tongji University; Shanghai China
| | - Xin-Yi Wang
- Institute of Protein Research, College of Life Sciences and Technology; Tongji University; Shanghai China
| | - Ge Song
- Institute of Protein Research, College of Life Sciences and Technology; Tongji University; Shanghai China
| | - Xiao-Xia Shao
- Institute of Protein Research, College of Life Sciences and Technology; Tongji University; Shanghai China
| | - Zhan-Yun Guo
- Institute of Protein Research, College of Life Sciences and Technology; Tongji University; Shanghai China
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New therapeutic approaches to treating hypertension in pregnancy. Drug Discov Today 2012; 17:1307-15. [DOI: 10.1016/j.drudis.2012.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Revised: 06/11/2012] [Accepted: 07/06/2012] [Indexed: 02/04/2023]
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Fiengo M, Donizetti A, del Gaudio R, Minucci S, Aniello F. Characterization, cDNA cloning and expression pattern of relaxin gene during embryogenesis of Danio rerio. Dev Growth Differ 2012; 54:579-87. [DOI: 10.1111/j.1440-169x.2012.01361.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 05/04/2012] [Accepted: 05/06/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Marcella Fiengo
- Department of Biological Sciences; University of Naples Federico II; Via Mezzocannone 8; 80134; Napoli; Italy
| | - Aldo Donizetti
- Department of Biological Sciences; University of Naples Federico II; Via Mezzocannone 8; 80134; Napoli; Italy
| | - Rosanna del Gaudio
- Department of Biological Sciences; University of Naples Federico II; Via Mezzocannone 8; 80134; Napoli; Italy
| | - Sergio Minucci
- Department of Experimental Medicine; Second University of Naples; Via Costantinopoli 16; 80138; Napoli; Italy
| | - Francesco Aniello
- Department of Biological Sciences; University of Naples Federico II; Via Mezzocannone 8; 80134; Napoli; Italy
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Alvarez-Jaimes L, Sutton SW, Nepomuceno D, Motley ST, Cik M, Stocking E, Shoblock J, Bonaventure P. In vitro pharmacological characterization of RXFP3 allosterism: an example of probe dependency. PLoS One 2012; 7:e30792. [PMID: 22347403 PMCID: PMC3274524 DOI: 10.1371/journal.pone.0030792] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 12/29/2011] [Indexed: 11/18/2022] Open
Abstract
Recent findings suggest that the relaxin-3 neural network may represent a new ascending arousal pathway able to modulate a range of neural circuits including those affecting circadian rhythm and sleep/wake states, spatial and emotional memory, motivation and reward, the response to stress, and feeding and metabolism. Therefore, the relaxin-3 receptor (RXFP3) is a potential therapeutic target for the treatment of various CNS diseases. Here we describe a novel selective RXFP3 receptor positive allosteric modulator (PAM), 3-[3,5-Bis(trifluoromethyl)phenyl]-1-(3,4-dichlorobenzyl)-1-[2-(5-methoxy-1H-indol-3-yl)ethyl]urea (135PAM1). Calcium mobilization and cAMP accumulation assays in cell lines expressing the cloned human RXFP3 receptor show the compound does not directly activate RXFP3 receptor but increases functional responses to amidated relaxin-3 or R3/I5, a chimera of the INSL5 A chain and the Relaxin-3 B chain. 135PAM1 increases calcium mobilization in the presence of relaxin-3(NH2) and R3/I5(NH2) with pEC50 values of 6.54 (6.46 to 6.64) and 6.07 (5.94 to 6.20), respectively. In the cAMP accumulation assay, 135PAM1 inhibits the CRE response to forskolin with a pIC50 of 6.12 (5.98 to 6.27) in the presence of a probe (10 nM) concentration of relaxin-3(NH2). 135PAM1 does not compete for binding with the orthosteric radioligand, [(125)I] R3I5 (amide), in membranes prepared from cells expressing the cloned human RXFP3 receptor. 135PAM1 is selective for RXFP3 over RXFP4, which also responds to relaxin-3. However, when using the free acid (native) form of relaxin-3 or R3/I5, 135PAM1 doesn't activate RXFP3 indicating that the compound's effect is probe dependent. Thus one can exchange the entire A-chain of the probe peptide while retaining PAM activity, but the state of the probe's c-terminus is crucial to allosteric activity of the PAM. These data demonstrate the existence of an allosteric site for modulation of this GPCR as well as the subtlety of changes in probe molecules that can affect allosteric modulation of RXFP3.
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Affiliation(s)
- Lily Alvarez-Jaimes
- Janssen Pharmaceutical Companies of Johnson & Johnson, San Diego, California, United States of America
| | - Steven W. Sutton
- Janssen Pharmaceutical Companies of Johnson & Johnson, San Diego, California, United States of America
| | - Diane Nepomuceno
- Janssen Pharmaceutical Companies of Johnson & Johnson, San Diego, California, United States of America
| | - S. Timothy Motley
- Janssen Pharmaceutical Companies of Johnson & Johnson, San Diego, California, United States of America
| | - Miroslav Cik
- Janssen Pharmaceutical Companies of Johnson & Johnson, San Diego, California, United States of America
| | - Emily Stocking
- Janssen Pharmaceutical Companies of Johnson & Johnson, San Diego, California, United States of America
| | - James Shoblock
- Janssen Pharmaceutical Companies of Johnson & Johnson, San Diego, California, United States of America
| | - Pascal Bonaventure
- Janssen Pharmaceutical Companies of Johnson & Johnson, San Diego, California, United States of America
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Lee WJ, Kim YO, Choi IK, Rah DK, Yun CO. Adenovirus-relaxin gene therapy for keloids: implication for reversing pathological fibrosis. Br J Dermatol 2012; 165:673-7. [PMID: 21623756 DOI: 10.1111/j.1365-2133.2011.10439.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Keloids or hypertrophic scars are pathological proliferations of the dermal skin layer resulting from excessive collagen deposition. Because the hormone relaxin (RLX) inhibits collagen synthesis and expression in stimulated fibroblasts, an adenovirus expressing RLX (dE1-RGD/lacZ/RLX) was generated. OBJECTIVES To investigate the effect of RLX-expressing adenovirus on expression of various extracellular matrix (ECM) components in primary keloid spheroids. METHODS The expression levels of type I and III collagen, fibronectin and elastin were investigated by immunohistochemistry in primary keloid spheroids transduced with the RLX-expressing adenovirus. RESULTS Immunohistochemical analysis showed that expression of major ECM components (e.g. type I and III collagen, elastin and fibronectin) was markedly reduced in primary keloid spheroids transduced with dE1-RGD/lacZ/RLX. CONCLUSIONS These results suggest that the antifibrotic effect of RLX-expressing adenovirus may have therapeutic effects on keloids by reversing pathological fibrosis and preventing keloid recurrence after surgical excision.
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Affiliation(s)
- W J Lee
- Institute for Human Tissue Restoration, Department of Plastic and Reconstructive Surgery, Yonsei University College of Medicine, Seoul, Korea
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Feugang JM, Greene JM, Willard ST, Ryan PL. In vitro effects of relaxin on gene expression in porcine cumulus-oocyte complexes and developing embryos. Reprod Biol Endocrinol 2011; 9:15. [PMID: 21272344 PMCID: PMC3045296 DOI: 10.1186/1477-7827-9-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 01/27/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Relaxin hormone peptide is found in porcine follicular and utero-tubal fluids, but its possible actions during early embryo development are still undetermined. Here, we investigated the effects of porcine relaxin during oocyte maturation and embryo development, and gene expression in the pig. METHODS Immature cumulus-oocyte complexes (COCs) were obtained from ovarian follicles of sows. In experiment 1, COCs were matured in the presence of 0, 20, or 40 ng relaxin/ml, or 10% (v/v) porcine follicular fluid. In experiment 2, COCs were in vitro matured, fertilized and resulting embryos were cultured in the presence of 0, 20, or 40 ng relaxin/ml. In experiment 3, COCs were matured in the presence of 40 ng relaxin/ml, fertilized and zygotes were cultured as indicated in experiment 2. We evaluated the proportions of matured oocytes in experiment 1, cleaved and blastocysts on Day 2 and Day 7 post insemination in all experiments. The total cell number of blastocysts was also evaluated. In parallel, transcription levels of both relaxin and its receptors (RXFP1 and RXFP2), as well as a pro- (Bax) and anti- (Bcl2-like 1) apoptotic-related genes were determined. All data were analyzed by ANOVA and significant differences were fixed for P < 0.05. RESULTS In experiment 1, relaxin significantly increased the proportions of matured oocytes and cleaved embryos, as well as the expression level of RXFP2 mRNA compared to RXFP1 (P < 0.05). There was no effect on endogenous expression of relaxin and Bcl2-like1/Bax ratios. In all experiments, relaxin did not affect the proportions of blastocysts, but did significantly increase their total cell numbers (P < 0.05). Furthermore, no effect of relaxin was observed on Bcl2-like1/Bax expression ratios, which were similar between groups. CONCLUSIONS Exogenous relaxin influences its own receptors expression, improves oocyte nuclear maturation. Its beneficial effect on total cell number of blastocysts appears to be through a Bcl2-like1/Bax-independent mechanism.
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Affiliation(s)
- Jean M Feugang
- Department of Animal & Dairy Sciences, Mississippi State University, 4025 Wise Center Dr, Mississippi State, MS 38762, USA
| | - Jonathan M Greene
- Department of Animal & Dairy Sciences, Mississippi State University, 4025 Wise Center Dr, Mississippi State, MS 38762, USA
| | - Scott T Willard
- Department of Biochemistry & Molecular Biology, Mississippi State University, 402 Dorman Hall, Mississippi, MS 38762, USA
| | - Peter L Ryan
- Department of Animal & Dairy Sciences, Mississippi State University, 4025 Wise Center Dr, Mississippi State, MS 38762, USA
- Department of Pathobiology & Population Medicine, Mississippi State University, 240 Wise Center Dr, Mississippi State, MS 38762, USA
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Dragoo JL, Castillo TN, Korotkova TA, Kennedy AC, Kim HJ, Stewart DR. Trends in serum relaxin concentration among elite collegiate female athletes. Int J Womens Health 2011; 3:19-24. [PMID: 21339934 PMCID: PMC3039005 DOI: 10.2147/ijwh.s14188] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Indexed: 11/23/2022] Open
Abstract
PURPOSE This study was designed to investigate the relationship between serum relaxin concentration (SRC) and menstrual history and hormonal contraceptive use among elite collegiate female athletes. Evaluation of SRC in athletes is necessary, because relaxin has been associated with increased knee joint laxity and decreased anterior cruciate ligament (ACL) strength in animal models. METHODS National Collegiate Athletic Association Division I female athletes participating in sports at high risk for ACL tears - basketball, field hockey, gymnastics, lacrosse, soccer, and volleyball - were invited to participate. All participants completed a questionnaire about their menstrual history and hormonal contraceptive use. Venipuncture was performed to obtain samples of serum progesterone and relaxin. Samples were obtained during the mid-luteal phase from ovulating participants, and between the actual or projected cycle days 21 to 24, from anovulatory participants. Serum concentration of relaxin and progesterone was determined by ELISA and the data were analyzed using SPSS statistical software with significance set at P = 0.05. RESULTS 169 female athletes participated. The mean SRC among all participants was 3.08 ± 6.66 pg/mL). The mean SRC differed significantly between those participants using hormonal contraceptives (1.41 pg/mL) and those not using hormonal contraceptives (3.08 pg/mL, P = 0.002). Mean SRC was lowest among amenorrheic participants (1.02 pg/mL) and highest among oligomenorrheic participants (3.71 pg/mL) and eumenorrheic participants (3.06 pg/mL); these differences were not significant (P = 0.53). Mean serum progesterone concentration (SPC) differed significantly between those participants using hormonal contraceptives (2.80 ng/mL), and those not using hormonal contraceptives (6.99 ng/mL, P < 0.0001). CONCLUSIONS There is a positive correlation between serum progesterone and SRC and an attenuation of SRC with hormonal contraceptive use. Our results underscore the significant role that hormonal contraceptives can play in decreasing relaxin levels, if future investigations establish a link between relaxin levels and ligamentous injury among female athletes.
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Affiliation(s)
- Jason L Dragoo
- Department of Orthopaedic Surgery, Stanford University, Palo Alto, CA, USA
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Pini A, Shemesh R, Samuel CS, Bathgate RAD, Zauberman A, Hermesh C, Wool A, Bani D, Rotman G. Prevention of bleomycin-induced pulmonary fibrosis by a novel antifibrotic peptide with relaxin-like activity. J Pharmacol Exp Ther 2010; 335:589-99. [PMID: 20826567 DOI: 10.1124/jpet.110.170977] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Pulmonary fibrosis is a progressive and lethal lung disease characterized by accumulation of extracellular matrix and loss of pulmonary function. No cure exists for this pathologic condition, and current treatments often fail to slow its progression or relieve its symptoms. Relaxin was previously shown to induce a matrix-degrading phenotype in human lung fibroblasts in vitro and to inhibit pulmonary fibrosis in vivo. A novel peptide that targets the relaxin RXFP1/LGR7 receptor was recently identified using our computational platform designed to predict novel G protein-coupled receptor peptide agonists. In this study, we examined the antifibrotic properties of this novel peptide, designated CGEN25009, in human cell-based assays and in a murine model of bleomycin-induced pulmonary fibrosis. Similar to relaxin, CGEN25009 was found to have an inhibitory effect on transforming growth factor-β1-induced collagen deposition in human dermal fibroblasts and to enhance MMP-2 expression. The peptide's biological activity was also similar to relaxin in generating cellular stimulation of cAMP, cGMP, and NO in the THP-1 human cell line. In vivo, 2-week administration of CGEN25009 in a preventive or therapeutic mode (i.e., concurrently with or 7 days after bleomycin treatment, respectively) caused a significant reduction in lung inflammation and injury and ameliorated adverse airway remodeling and peribronchial fibrosis. The results of this study indicate that CGEN25009 displays antifibrotic and anti-inflammatory properties and may offer a new therapeutic option for the treatment of pulmonary fibrosis.
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Halls ML, Cooper DMF. Sub-picomolar relaxin signalling by a pre-assembled RXFP1, AKAP79, AC2, beta-arrestin 2, PDE4D3 complex. EMBO J 2010; 29:2772-87. [PMID: 20664520 PMCID: PMC2924647 DOI: 10.1038/emboj.2010.168] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Accepted: 07/01/2010] [Indexed: 12/17/2022] Open
Abstract
Biochemical studies suggest that G-protein-coupled receptors (GPCRs) achieve exquisite signalling specificity by forming selective complexes, termed signalosomes. Here, using cAMP biosensors in single cells, we uncover a pre-assembled, constitutively active GPCR signalosome, that couples the relaxin receptor, relaxin family peptide receptor 1 (RXFP1), to cAMP following receptor stimulation with sub-picomolar concentrations of peptide. The physiological effects of relaxin, a pleiotropic hormone with therapeutic potential in cancer metastasis and heart failure, are generally attributed to local production of the peptide, that occur in response to sub-micromolar concentrations. The highly sensitive signalosome identified here provides a regulatory mechanism for the extremely low levels of relaxin that circulate. The signalosome includes requisite Galpha(s), Gbetagamma and adenylyl cyclase 2 (AC2); AC2 is functionally coupled to RXFP1 through AKAP79 binding to helix 8 of the receptor; activation of AC2 is tonically opposed by protein kinase A (PKA)-activated PDE4D3, scaffolded through a beta-arrestin 2 interaction with Ser(704) of the receptor C-terminus. This elaborate, pre-assembled, ligand-independent GPCR signalosome represents a new paradigm in GPCR signalling and provides a mechanism for the distal actions of low circulating levels of relaxin.
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Affiliation(s)
- Michelle L Halls
- Department of Pharmacology, University of Cambridge, Cambridge, UK
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Hombach-Klonisch S, Bialek J, Radestock Y, Truong A, Agoulnik AI, Fiebig B, Willing C, Weber E, Hoang-Vu C, Klonisch T. INSL3 has tumor-promoting activity in thyroid cancer. Int J Cancer 2010; 127:521-31. [PMID: 19950223 DOI: 10.1002/ijc.25068] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The functional role of INSL3 and its receptor RXFP2 in carcinogenesis is largely unknown. We have previously demonstrated (pro-)cathepsin-L as a target of INSL3 in human thyroid cancer cells facilitating penetration of tumor cells through elastin matrices. We demonstrate the expression of RXFP2 in human thyroid tissues and in mouse follicular thyroid epithelial cells using Cre-recombinase transgene driven by Rxfp2 promoter. Recombinant and secreted INSL3 increased the motility of thyroid carcinoma (TC) cells in an autocrine/paracrine manner. This effect required the presence of RXFP2. We identified S100A4 as a novel INSL3 target molecule and showed that S100A4 facilitated INSL3-induced enhanced motility. Stable transfectants of the human follicular TC cell line FTC-133 expressing and secreting bioactive human INSL3 displayed enhanced anchorage-independent growth in soft agar assays. Xenotransplant experiments in nude mice showed that INSL3, but not EGFP-mock transfectants, developed fast-growing and highly vascularized xenografts. We used human umbilical vein endothelial cells in capillary tube formation assays to demonstrate increased 2-dimensional tube formations induced by recombinant human INSL3 and human S100A4 comparable to the effect of vascular endothelial growth factor used as positive control. We conclude that INSL3 is a powerful and multifunctional promoter of tumor growth and angiogenesis in human thyroid cancer cell xenografts. INSL3 actions involve RXFP2 activation and the secretion of S100A4 and (pro-)cathepsin-L.
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Abstract
Relaxin is a naturally occurring human peptide initially identified as a reproductive hormone. More recently, relaxin has been shown to play a key role in the maternal hemodynamic and renal adjustments that accommodate pregnancy. An understanding of these physiologic effects has led to the evaluation of relaxin as a pharmacologic agent for the treatment of patients with acute heart failure. Preliminary results have been encouraging. In addition, the other known biologic properties of relaxin, including anti-inflammatory effects, extracellular matrix remodeling effects, and angiogenic and anti-ischemic effects, all may play a role in potential benefits of relaxin therapy. Ongoing, large-scale clinical testing will provide additional insights into the potential role of relaxin in the treatment of heart failure.
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Affiliation(s)
- Sam L. Teichman
- Corthera, Inc, a subsidiary of Novartis Pharmaceuticals Corp., 1660 South Amphlett Boulevard, Suite 200, San Mateo, CA 94402 USA
| | - Elaine Unemori
- Corthera, Inc, a subsidiary of Novartis Pharmaceuticals Corp., 1660 South Amphlett Boulevard, Suite 200, San Mateo, CA 94402 USA
| | - John R. Teerlink
- Section of Cardiology, Veterans Affairs Medical Center, University of California, San Francisco VA Medical Center, Cardiology-111C, Building 203, Room 2A-49, 4150 Clement Street, San Francisco, CA 94121-1545 USA
| | - Gad Cotter
- Momentum Research, Inc, 3100 Tower Boulevard, Suite 802, Durham, NC 27707 USA
| | - Marco Metra
- Section of Cardiovascular Diseases, Department of Experimental and Applied Medicine, University of Brescia, Cardiology, University and Civil Hospital, Piazza Spedali Civili 1, 25123 Brescia, Italy
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Abstract
The milk of many mammalian species contains hormones and growth factors in addition to nutrients and immuocompetent substances. These factors can be absorbed into the circulation of suckling neonates to exert important effects on metabolism and promote tissue and organ growth. Frequently, there is uncertainty as to whether such substances are gene products of the mammary glands themselves or are produced elsewhere and concentrated from the systemic circulation. The 6 kD polypeptide, relaxin, appears in milk of several mammalian species, including that of the rat, but proof of its source of secretion (corpus luteum vs. mammary gland) is so far lacking. The specific monoclonal anti-rat relaxin antibody MCA1 has previously been utilized successfully to investigate many of relaxin’s actions in the rat, including those affecting the development of the mammary apparatus. In this report, MCA1 was utilized to aid in the identification of the source of relaxin in rat milk. Treatment of lactating rats with MCA1 completely neutralized the luteal relaxin circulating in serum but did not decrease the concentration of immunoactive relaxin secreted in milk. Moreover, the antibody did not appear to reach the mammary epithelium. The evidence thus supports the view that in the rat, the relaxin secreted in milk is primarily a product of the mammary glands and not concentrated from the systemic circulation.
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Tregear GW, Bathgate RAD, Hossain MA, Lin F, Zhang S, Shabanpoor F, Scott DJ, Ma S, Gundlach AL, Samuel CS, Wade JD. Structure and Activity in the Relaxin Family of Peptides. Ann N Y Acad Sci 2009; 1160:5-10. [DOI: 10.1111/j.1749-6632.2009.03955.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Nandi D, Bhosale M. Neuronal modulation of the immune response. J Biosci 2009; 33:635-7. [PMID: 19179750 DOI: 10.1007/s12038-008-0082-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Dipankae Nandi
- Department of Biochemistry,Indian Institute of Science, Bangalore 560 012, India.
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Halls ML, van der Westhuizen ET, Wade JD, Evans BA, Bathgate RAD, Summers RJ. Relaxin family peptide receptor (RXFP1) coupling to G(alpha)i3 involves the C-terminal Arg752 and localization within membrane Raft Microdomains. Mol Pharmacol 2008; 75:415-28. [PMID: 19029286 DOI: 10.1124/mol.108.051227] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The relaxin family peptide receptors (RXFP) 1 and 2 are targets for the relaxin family peptides relaxin and insulin-like peptide 3 (INSL3), respectively. Although both receptors and peptides share a high degree of sequence identity, the cAMP signaling pathways activated by the two systems are quite distinct. Relaxin activation of RXFP1 initially results in accumulation of cAMP via G(alpha)(s), but this is modulated by inhibition of cAMP through G(alpha)(oB). Over time, RXFP1 recruits coupling to G(alpha)(i3), causing additional cAMP accumulation via a G(alpha)(i3)-Gbetagamma-phosphoinositide 3-kinase (PI3K)-protein kinase C (PKC)zeta pathway. In contrast, INSL3 activation of RXFP2 results in accumulation of cAMP only via G(alpha)(s), modulated by cAMP inhibition through G(alpha)(oB). Thus, the aim of this study was to identify the cause of differential G-protein coupling between these highly similar receptors. Construction of chimeric receptors revealed that G(alpha)(i3) coupling is dependent upon the transmembrane region of RXFP1 and independent of the receptor ectodomain or ligand bound. Generation of C-terminal truncated receptors identified the terminal 10 amino acids of the RXFP1 C terminus as essential for G(alpha)(i3) signaling, and point mutations revealed an obligatory role for Arg(752). RXFP1-mediated G(alpha)(i3), but not G(alpha)(s) or G(alpha)(oB), signaling was also found to be dependent upon membrane rafts, and RXFP1 coupled to G(alpha)(i3) after only 3 min of receptor stimulation. Therefore, RXFP1 coupling to the G(alpha)(i3)-Gbetagamma-PI3K-PKCzeta pathway requires the terminal 10 amino acids of the RXFP1 C terminus and membrane raft localization, and the observed delay in this pathway occurs downstream of G(alpha)(i3).
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Affiliation(s)
- Michelle L Halls
- Monash Institute for Pharmaceutical Sciences, Parkville, Australia
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