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Sethi A, Bruell S, Patil N, Hossain MA, Scott DJ, Petrie EJ, Bathgate RAD, Gooley PR. The complex binding mode of the peptide hormone H2 relaxin to its receptor RXFP1. Nat Commun 2016; 7:11344. [PMID: 27088579 PMCID: PMC4837482 DOI: 10.1038/ncomms11344] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/16/2016] [Indexed: 11/20/2022] Open
Abstract
H2 relaxin activates the relaxin family peptide receptor-1 (RXFP1), a class A G-protein coupled receptor, by a poorly understood mechanism. The ectodomain of RXFP1 comprises an N-terminal LDLa module, essential for activation, tethered to a leucine-rich repeat (LRR) domain by a 32-residue linker. H2 relaxin is hypothesized to bind with high affinity to the LRR domain enabling the LDLa module to bind and activate the transmembrane domain of RXFP1. Here we define a relaxin-binding site on the LDLa-LRR linker, essential for the high affinity of H2 relaxin for the ectodomain of RXFP1, and show that residues within the LDLa-LRR linker are critical for receptor activation. We propose H2 relaxin binds and stabilizes a helical conformation of the LDLa-LRR linker that positions residues of both the linker and the LDLa module to bind the transmembrane domain and activate RXFP1. The mechanism by which relaxin activates the relaxin family peptide receptor-1 is poorly understood. Here, Sethi et al. identify a relaxin binding site in an extracellular linker between the LDLa and LRR domains and propose that relaxin binding stabilizes a helical conformation that leads to receptor activation.
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Affiliation(s)
- Ashish Sethi
- Department of Biochemistry &Molecular Biology, The University of Melbourne, Victoria 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Shoni Bruell
- Department of Biochemistry &Molecular Biology, The University of Melbourne, Victoria 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia.,Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Nitin 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
| | - Mohammed Akhter Hossain
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia.,Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Daniel J Scott
- Department of Biochemistry &Molecular Biology, The University of Melbourne, Victoria 3010, Australia.,Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Emma J Petrie
- Department of Biochemistry &Molecular Biology, The University of Melbourne, Victoria 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Ross A D Bathgate
- Department of Biochemistry &Molecular Biology, The University of Melbourne, Victoria 3010, Australia.,Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Paul R Gooley
- Department of Biochemistry &Molecular Biology, The University of Melbourne, Victoria 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
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Hu X, Myhr C, Huang Z, Xiao J, Barnaeva E, Ho BA, Agoulnik IU, Ferrer M, Marugan JJ, Southall N, Agoulnik AI. Structural Insights into the Activation of Human Relaxin Family Peptide Receptor 1 by Small-Molecule Agonists. Biochemistry 2016; 55:1772-83. [PMID: 26866459 DOI: 10.1021/acs.biochem.5b01195] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The GPCR relaxin family peptide receptor 1 (RXFP1) mediates the action of relaxin peptide hormone, including its tissue remodeling and antifibrotic effects. The peptide has a short half-life in plasma, limiting its therapeutic utility. However, small-molecule agonists of human RXFP1 can overcome this limitation and may provide a useful therapeutic approach, especially for chronic diseases such as heart failure and fibrosis. The first small-molecule agonists of RXFP1 were recently identified from a high-throughput screening, using a homogeneous cell-based cAMP assay. Optimization of the hit compounds resulted in a series of highly potent and RXFP1 selective agonists with low cytotoxicity, and excellent in vitro ADME and pharmacokinetic properties. Here, we undertook extensive site-directed mutagenesis studies in combination with computational modeling analysis to probe the molecular basis of the small-molecule binding to RXFP1. The results showed that the agonists bind to an allosteric site of RXFP1 in a manner that closely interacts with the seventh transmembrane domain (TM7) and the third extracellular loop (ECL3). Several residues were determined to play an important role in the agonist binding and receptor activation, including a hydrophobic region at TM7 consisting of W664, F668, and L670. The G659/T660 motif within ECL3 is crucial to the observed species selectivity of the agonists for RXFP1. The receptor binding and activation effects by the small molecule ML290 were compared with the cognate ligand, relaxin, providing valuable insights on the structural basis and molecular mechanism of receptor activation and selectivity for RXFP1.
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Affiliation(s)
- Xin Hu
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health , 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | | | | | - Jingbo Xiao
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health , 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Elena Barnaeva
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health , 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | | | | | - Marc Ferrer
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health , 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Juan J Marugan
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health , 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Noel Southall
- NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health , 9800 Medical Center Drive, Rockville, Maryland 20850, United States
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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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54
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Wu QP, Zhang L, Shao XX, Wang JH, Gao Y, Xu ZG, Liu YL, Guo ZY. Application of the novel bioluminescent ligand-receptor binding assay to relaxin-RXFP1 system for interaction studies. Amino Acids 2016; 48:1099-1107. [PMID: 26767372 DOI: 10.1007/s00726-015-2146-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 11/27/2015] [Indexed: 10/22/2022]
Abstract
Relaxin is a prototype of the relaxin family peptide hormones and plays important biological functions by binding and activating the G protein-coupled receptor RXFP1. To study their interactions, in the present work, we applied the newly developed bioluminescent ligand-receptor binding assay to the relaxin-RXFP1 system. First, a fully active easily labeled relaxin, in which three Lys residues of human relaxin-2 were replaced by Arg, was prepared through overexpression of a single-chain precursor in Pichia pastoris and in vitro enzymatic maturation. Thereafter, the B-chain N-terminus of the easily labeled relaxin was chemically cross-linked with a C-terminal cysteine residue of an engineered NanoLuc through a disulfide linkage. Receptor-binding assays demonstrated that the NanoLuc-conjugated relaxin retained high binding affinity with the receptor RXFP1 (K d = 1.11 ± 0.08 nM, n = 3) and was able to sensitively monitor binding of a variety of ligands with RXFP1. Using the novel bioluminescent binding assay, we demonstrated that three highly conserved B-chain Arg residues of relaxin-3 had distinct contributions to binding of the receptor RXFP1. In summary, our present work provides a novel bioluminescent ligand-receptor binding assay for the relaxin-RXFP1 system to facilitate their interaction studies, such as characterization of relaxin analogues or screening novel agonists or antagonists of RXFP1.
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Affiliation(s)
- Qing-Ping Wu
- Research Center for Translational Medicine at East Hospital, College of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Lei Zhang
- Research Center for Translational Medicine at East Hospital, College of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xiao-Xia Shao
- Research Center for Translational Medicine at East Hospital, College of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jia-Hui Wang
- Research Center for Translational Medicine at East Hospital, College of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Yu Gao
- Research Center for Translational Medicine at East Hospital, College of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Zeng-Guang Xu
- Research Center for Translational Medicine at East Hospital, College of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Ya-Li Liu
- Research Center for Translational Medicine at East Hospital, College of Life Sciences and Technology, Tongji University, Shanghai, China.
| | - Zhan-Yun Guo
- Research Center for Translational Medicine at East Hospital, College of Life Sciences and Technology, Tongji University, Shanghai, China.
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55
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Halls ML, Bathgate RAD, Sutton SW, Dschietzig TB, Summers RJ. International Union of Basic and Clinical Pharmacology. XCV. Recent advances in the understanding of the pharmacology and biological roles of relaxin family peptide receptors 1-4, the receptors for relaxin family peptides. Pharmacol Rev 2015; 67:389-440. [PMID: 25761609 DOI: 10.1124/pr.114.009472] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Relaxin, insulin-like peptide 3 (INSL3), relaxin-3, and INSL5 are the cognate ligands for the relaxin family peptide (RXFP) receptors 1-4, respectively. RXFP1 activates pleiotropic signaling pathways including the signalosome protein complex that facilitates high-sensitivity signaling; coupling to Gα(s), Gα(i), and Gα(o) proteins; interaction with glucocorticoid receptors; and the formation of hetero-oligomers with distinctive pharmacological properties. In addition to relaxin-related ligands, RXFP1 is activated by Clq-tumor necrosis factor-related protein 8 and by small-molecular-weight agonists, such as ML290 [2-isopropoxy-N-(2-(3-(trifluoromethylsulfonyl)phenylcarbamoyl)phenyl)benzamide], that act allosterically. RXFP2 activates only the Gα(s)- and Gα(o)-coupled pathways. Relaxin-3 is primarily a neuropeptide, and its cognate receptor RXFP3 is a target for the treatment of depression, anxiety, and autism. A variety of peptide agonists, antagonists, biased agonists, and an allosteric modulator target RXFP3. Both RXFP3 and the related RXFP4 couple to Gα(i)/Gα(o) proteins. INSL5 has the properties of an incretin; it is secreted from the gut and is orexigenic. The expression of RXFP4 in gut, adipose tissue, and β-islets together with compromised glucose tolerance in INSL5 or RXFP4 knockout mice suggests a metabolic role. This review focuses on the many advances in our understanding of RXFP receptors in the last 5 years, their signal transduction mechanisms, the development of novel compounds that target RXFP1-4, the challenges facing the field, and current prospects for new therapeutics.
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Affiliation(s)
- Michelle L Halls
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Ross A D Bathgate
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Steve W Sutton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Thomas B Dschietzig
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
| | - Roger J Summers
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (M.L.H., R.J.S.); Neuropeptides Division, Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia (R.A.D.B.); Neuroscience Drug Discovery, Janssen Research & Development, LLC, San Diego, California (S.W.S.); Immundiagnostik AG, Bensheim, Germany (T.B.D.); and Charité-University Medicine Berlin, Campus Mitte, Medical Clinic for Cardiology and Angiology, Berlin, Germany (T.B.D.)
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56
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Calvez J, Lenglos C, de Ávila C, Guèvremont G, Timofeeva E. Differential effects of central administration of relaxin-3 on food intake and hypothalamic neuropeptides in male and female rats. GENES BRAIN AND BEHAVIOR 2015; 14:550-63. [DOI: 10.1111/gbb.12236] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 07/25/2015] [Accepted: 07/26/2015] [Indexed: 12/22/2022]
Affiliation(s)
- J. Calvez
- Faculté de Médecine, Département de Psychiatrie et de Neurosciences, Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec; Université Laval; Québec (QC) Canada
| | - C. Lenglos
- Faculté de Médecine, Département de Psychiatrie et de Neurosciences, Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec; Université Laval; Québec (QC) Canada
| | - C. de Ávila
- Faculté de Médecine, Département de Psychiatrie et de Neurosciences, Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec; Université Laval; Québec (QC) Canada
| | - G. Guèvremont
- Faculté de Médecine, Département de Psychiatrie et de Neurosciences, Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec; Université Laval; Québec (QC) Canada
| | - E. Timofeeva
- Faculté de Médecine, Département de Psychiatrie et de Neurosciences, Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec; Université Laval; Québec (QC) Canada
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57
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Van Hiel MB, Vandersmissen HP, Proost P, Vanden Broeck J. Cloning, constitutive activity and expression profiling of two receptors related to relaxin receptors in Drosophila melanogaster. Peptides 2015; 68:83-90. [PMID: 25064813 DOI: 10.1016/j.peptides.2014.07.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 07/04/2014] [Accepted: 07/07/2014] [Indexed: 10/25/2022]
Abstract
Leucine-rich repeat containing G protein-coupled receptors (LGRs) comprise a cluster of transmembrane proteins, characterized by the presence of a large N-terminal extracellular domain. This receptor group can be classified into three subtypes. Belonging to the subtype C LGRs are the mammalian relaxin receptors LGR7 (RXFP1) and LGR8 (RXFP2), which mediate important reproductive and other processes. We identified two related receptors in the genome of the fruit fly and cloned their open reading frames into an expression vector. Interestingly, dLGR3 demonstrated constitutive activity at very low doses of transfected plasmid, whereas dLGR4 did not show any basal activity. Both receptors exhibited a similar expression pattern during development, with relatively high transcript levels during the first larval stage. In addition, both receptors displayed higher expression in male adult flies as compared to female flies. Analysis of the tissue distribution of both receptor transcripts revealed a high expression of dLGR3 in the female fat body, while the expression of dLGR4 peaked in the midgut of both the wandering and adult stage.
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Affiliation(s)
- Matthias B Van Hiel
- Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, P.O. Box 2465, B-3000 Leuven, Belgium
| | - Hans Peter Vandersmissen
- Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, P.O. Box 2465, B-3000 Leuven, Belgium
| | - Paul Proost
- Molecular Immunology, Department of Microbiology and Immunology, KU Leuven, Minderbroedersstraat 10, P.O. Box 1030, B-3000 Leuven, Belgium
| | - Jozef Vanden Broeck
- Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, P.O. Box 2465, B-3000 Leuven, Belgium.
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58
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Haugaard-Kedström LM, Wong LLL, Bathgate RAD, Rosengren KJ. Synthesis and pharmacological characterization of a europium-labelled single-chain antagonist for binding studies of the relaxin-3 receptor RXFP3. Amino Acids 2015; 47:1267-71. [DOI: 10.1007/s00726-015-1961-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/07/2015] [Indexed: 10/23/2022]
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59
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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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60
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Kristensson L, Mayer G, Ploj K, Wetterlund M, Arlbrandt S, Björquist A, Wissing BM, Castaldo M, Larsson N. Partial agonist activity of R3(BΔ23-27)R/I5 at RXFP3--investigation of in vivo and in vitro pharmacology. Eur J Pharmacol 2015; 747:123-31. [PMID: 25496752 DOI: 10.1016/j.ejphar.2014.11.041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 11/05/2014] [Accepted: 11/27/2014] [Indexed: 11/30/2022]
Abstract
Relaxin family peptide receptor 3 (RXFP3) is a G-protein coupled receptor mainly expressed in the brain and involved in appetite regulation. Previous studies in lean Wistar rats during the light phase have shown that the chimeric peptide R3(BΔ23-27)R/I5 suppresses food intake stimulated by an RXFP3 agonist, but has no effect on food intake when administered alone. We wanted to further investigate if R3(BΔ23-27)R/I5 on its own is able to antagonize the basal tone of the relaxin-3/RXFP3 system and therefore characterized the pharmacology of R3(BΔ23-27)R/I5 in vivo and in vitro. R3(BΔ23-27)R/I5 was intracerebroventricularly (ICV) injected in diet induced obese (DIO) Wistar rats and food intake was automatically measured during the dark phase when feeding drive is high. In our hands, R3(BΔ23-27)R/I5 alone did not have a significant effect on food intake during 24h following administration. Consistent with previous results, relaxin-3 stimulated food intake in satiated lean rats. R3(BΔ23-27)R/I5 was characterized in vitro using [(35)S]-GTPγS binding and cAMP assays, both assessing Gαi-protein mediated signalling, and dynamic mass redistribution (DMR) assays capturing the integrated cell response. R3(BΔ23-27)R/I5 showed partial agonist activity in all three functional assays. Thus, since R3(BΔ23-27)R/I5 displays partial RXFP3 agonist properties in vitro, further in vivo studies including additional tool compounds are needed to address if antagonizing relaxin-3/RXFP3 basal tone is a therapeutically relevant mechanism to regulate food intake and body weight.
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Affiliation(s)
- Lisbeth Kristensson
- Discovery Sciences, AstraZeneca R&D Mölndal, Pepparedsleden 3, S-431 83 Mölndal, Sweden
| | - Gaëll Mayer
- Respiratory, Inflammatory and Autoimmune iMED, AstraZeneca R&D Mölndal, Pepparedsleden 3, S-431 83 Mölndal, Sweden; Cardiovascular and Metabolic Diseases iMED, AstraZeneca R&D Mölndal, Pepparedsleden 3, S-431 83 Mölndal, Sweden
| | - Karolina Ploj
- Cardiovascular and Metabolic Diseases iMED, AstraZeneca R&D Mölndal, Pepparedsleden 3, S-431 83 Mölndal, Sweden; DSM Laboratory Animal Science, AstraZeneca R&D Mölndal, Pepparedsleden 3, S-431 83 Mölndal, Sweden
| | - Martina Wetterlund
- Cardiovascular and Metabolic Diseases iMED, AstraZeneca R&D Mölndal, Pepparedsleden 3, S-431 83 Mölndal, Sweden
| | - Susanne Arlbrandt
- Respiratory, Inflammatory and Autoimmune iMED, AstraZeneca R&D Mölndal, Pepparedsleden 3, S-431 83 Mölndal, Sweden
| | - Anna Björquist
- Cardiovascular and Metabolic Diseases iMED, AstraZeneca R&D Mölndal, Pepparedsleden 3, S-431 83 Mölndal, Sweden
| | - Britt-Marie Wissing
- Respiratory, Inflammatory and Autoimmune iMED, AstraZeneca R&D Mölndal, Pepparedsleden 3, S-431 83 Mölndal, Sweden
| | - Marie Castaldo
- Discovery Sciences, AstraZeneca R&D Mölndal, Pepparedsleden 3, S-431 83 Mölndal, Sweden
| | - Niklas Larsson
- Discovery Sciences, AstraZeneca R&D Mölndal, Pepparedsleden 3, S-431 83 Mölndal, Sweden.
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61
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Petrie EJ, Lagaida S, Sethi A, Bathgate RAD, Gooley PR. In a Class of Their Own - RXFP1 and RXFP2 are Unique Members of the LGR Family. Front Endocrinol (Lausanne) 2015; 6:137. [PMID: 26441827 PMCID: PMC4561518 DOI: 10.3389/fendo.2015.00137] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/20/2015] [Indexed: 01/12/2023] Open
Abstract
The leucine-rich repeat-containing G protein-coupled receptors (LGRs) family consists of three groups: types A, B, and C and all contain a large extracellular domain (ECD) made up of the structural motif - the leucine-rich repeat (LRR). In the LGRs, the ECD binds the hormone or ligand, usually through the LRRs, that ultimately results in activation and signaling. Structures are available for the ECD of type A and B LGRs, but not the type C LGRs. This review discusses the structural features of LRR proteins, and describes the known structures of the type A and B LGRs and predictions that can be made for the type C LGRs. The mechanism of activation of the LGRs is discussed with a focus on the role of the low-density lipoprotein class A (LDLa) module, a unique feature of the type C LGRs. While the LDLa module is essential for activation of the type C LGRs, the molecular mechanism for this process is unknown. Experimental data for the potential interactions of the type C LGR ligands with the LRR domain, the transmembrane domain, and the LDLa module are summarized.
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Affiliation(s)
- Emma J. Petrie
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, Australia
| | - Samantha Lagaida
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, Australia
| | - Ashish Sethi
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, Australia
| | - Ross A. D. Bathgate
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, Australia
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Paul R. Gooley
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, Australia
- *Correspondence: Paul R. Gooley, Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, VIC 3010, Australia,
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Xu JG, Huang C, Yang Z, Jin M, Fu P, Zhang N, Luo J, Li D, Liu M, Zhou Y, Zhu Y. Crystal structure of LGR4-Rspo1 complex: insights into the divergent mechanisms of ligand recognition by leucine-rich repeat G-protein-coupled receptors (LGRs). J Biol Chem 2014; 290:2455-65. [PMID: 25480784 DOI: 10.1074/jbc.m114.599134] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Leucine-rich repeat G-protein-coupled receptors (LGRs) are a unique class of G-protein-coupled receptors characterized by a large extracellular domain to recognize ligands and regulate many important developmental processes. Among the three groups of LGRs, group B members (LGR4-6) recognize R-spondin family proteins (Rspo1-4) to stimulate Wnt signaling. In this study, we successfully utilized the "hybrid leucine-rich repeat technique," which fused LGR4 with the hagfish VLR protein, to obtain two recombinant human LGR4 proteins, LGR415 and LGR49. We determined the crystal structures of ligand-free LGR415 and the LGR49-Rspo1 complex. LGR4 exhibits a twisted horseshoe-like structure. Rspo1 adopts a flat and β-fold architecture and is bound in the concave surface of LGR4 in the complex through electrostatic and hydrophobic interactions. All the Rspo1-binding residues are conserved in LGR4-6, suggesting that LGR4-6 bind R-spondins through an identical surface. Structural analysis of our LGR4-Rspo1 complex with the previously determined LGR4 and LGR5 structures revealed that the concave surface of LGR4 is the sole binding site for R-spondins, suggesting a one-site binding model of LGR4-6 in ligand recognition. The molecular mechanism of LGR4-6 is distinct from the two-step mechanism of group A receptors LGR1-3 and the multiple-interface binding model of group C receptors LGR7-8, suggesting LGRs utilize the divergent mechanisms for ligand recognition. Our structures, together with previous reports, provide a comprehensive understanding of the ligand recognition by LGRs.
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Affiliation(s)
- Jin-Gen Xu
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
| | - Chunfeng Huang
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
| | - Zhengfeng Yang
- the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Mengmeng Jin
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
| | - Panhan Fu
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
| | - Ni Zhang
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
| | - Jian Luo
- the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Dali Li
- the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Mingyao Liu
- the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Yan Zhou
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
| | - Yongqun Zhu
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
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Liu Y, Song G, Shao XX, Liu YL, Guo ZY. Quantitative measurement of cell membrane receptor internalization by the nanoluciferase reporter: Using the G protein-coupled receptor RXFP3 as a model. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:688-94. [PMID: 25434927 DOI: 10.1016/j.bbamem.2014.11.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 11/14/2014] [Accepted: 11/17/2014] [Indexed: 11/25/2022]
Abstract
Nanoluciferase (NanoLuc) is a newly developed small luciferase reporter with the brightest bioluminescence to date. In the present work, we developed NanoLuc as a sensitive bioluminescent reporter to measure quantitatively the internalization of cell membrane receptors, based on the pH dependence of the reporter activity. The G protein-coupled receptor RXFP3, the cognate receptor of relaxin-3/INSL7, was used as a model receptor. We first generated stable HEK293T cells that inducibly coexpressed a C-terminally NanoLuc-tagged human RXFP3 and a C-terminally enhanced green fluorescent protein (EGFP)-tagged human RXFP3. The C-terminal EGFP-tag and NanoLuc-tag had no detrimental effects on the ligand-binding potency and intracellular trafficking of RXFP3. Based on the fluorescence of the tagged EGFP reporter, the ligand-induced RXFP3 internalization was visualized directly under a fluorescence microscope. Based on the bioluminescence of the tagged NanoLuc reporter, the ligand-induced RXFP3 internalization was measured quantitatively by a convenient bioluminescent assay. Coexpression of an EGFP-tagged inactive [E141R]RXFP3 had no detrimental effect on the ligand-binding potency and ligand-induced internalization of the NanoLuc-tagged wild-type RXFP3, suggesting that the mutant RXFP3 and wild-type RXFP3 worked independently. The present bioluminescent internalization assay could be extended to other G protein-coupled receptors and other cell membrane receptors to study ligand-receptor and receptor-receptor interactions.
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Affiliation(s)
- Yu Liu
- Institute of Protein Research, College of Life Sciences and Technology, Tongji University, Shanghai 200092, China; Central Laboratory, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Ge Song
- Institute of Protein Research, College of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Xiao-Xia Shao
- Institute of Protein Research, College of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Ya-Li Liu
- Central Laboratory, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Zhan-Yun Guo
- Institute of Protein Research, College of Life Sciences and Technology, Tongji University, Shanghai 200092, China; Central Laboratory, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China.
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Diepenhorst NA, Petrie EJ, Chen CZ, Wang A, Hossain MA, Bathgate RAD, Gooley PR. Investigation of interactions at the extracellular loops of the relaxin family peptide receptor 1 (RXFP1). J Biol Chem 2014; 289:34938-52. [PMID: 25352603 DOI: 10.1074/jbc.m114.600882] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Relaxin, an emerging pharmaceutical treatment for acute heart failure, activates the relaxin family peptide receptor (RXFP1), which is a class A G-protein-coupled receptor. In addition to the classic transmembrane (TM) domain, RXFP1 possesses a large extracellular domain consisting of 10 leucine-rich repeats and an N-terminal low density lipoprotein class A (LDLa) module. Relaxin-mediated activation of RXFP1 requires multiple coordinated interactions between the ligand and various receptor domains including a high affinity interaction involving the leucine-rich repeats and a predicted lower affinity interaction involving the extracellular loops (ELs). The LDLa is essential for signal activation; therefore the ELs/TM may additionally present an interaction site to facilitate this LDLa-mediated signaling. To overcome the many challenges of investigating relaxin and the LDLa module interactions with the ELs, we engineered the EL1 and EL2 loops onto a soluble protein scaffold, mapping specific ligand and loop interactions using nuclear magnetic resonance spectroscopy. Key EL residues were subsequently mutated in RXFP1, and changes in function and relaxin binding were assessed alongside the RXFP1 agonist ML290 to monitor the functional integrity of the TM domain of these mutant receptors. The outcomes of this work make an important contribution to understanding the mechanism of RXFP1 activation and will aid future development of small molecule RXFP1 agonists/antagonists.
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Affiliation(s)
- Natalie A Diepenhorst
- From the Florey Institute of Neuroscience and Mental Health, the Department of Biochemistry and Molecular Biology, and
| | - Emma J Petrie
- the Department of Biochemistry and Molecular Biology, and
| | - Catherine Z Chen
- the National Center for Advancing Translational Sciences, Division of Preclinical Innovation, National Institutes of Health, Rockville, Maryland 20850
| | - Amy Wang
- the National Center for Advancing Translational Sciences, Division of Preclinical Innovation, National Institutes of Health, Rockville, Maryland 20850
| | - Mohammed Akhter Hossain
- From the Florey Institute of Neuroscience and Mental Health, the School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia and
| | - Ross A D Bathgate
- From the Florey Institute of Neuroscience and Mental Health, the Department of Biochemistry and Molecular Biology, and
| | - Paul R Gooley
- the Department of Biochemistry and Molecular Biology, and
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Kusakabe M, Ishikawa A, Kitano J. Relaxin-related gene expression differs between anadromous and stream-resident stickleback (Gasterosteus aculeatus) following seawater transfer. Gen Comp Endocrinol 2014; 205:197-206. [PMID: 24973563 DOI: 10.1016/j.ygcen.2014.06.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 06/09/2014] [Accepted: 06/15/2014] [Indexed: 10/25/2022]
Abstract
Relaxin (RLN) is a hormone that was originally identified as a regulator of pregnancy and reproduction. However, recent mammalian studies have demonstrated that relaxins also have potent osmoregulatory actions. In mammals, six relaxin family peptides have been identified: RLN1/2, RLN3, insulin-like peptide (INSL) 3, INSL4, INSL5, and INSL6. Previous genome database searches have revealed that teleosts also possess multiple relaxin family genes. However, the functions of these relaxin family peptides in teleosts remain unclear. In order to gain insight into the osmoregulatory functions of teleost relaxins, we studied the relaxin family peptides in euryhaline three-spined sticklebacks (Gasterosteus aculeatus), which have diversified into a variety of ecotypes. Rln3a, rln3b, and rln transcripts were abundant in the stickleback brain, whereas insl5b transcript levels were highest in the intestine among tissues. Seawater challenge experiments showed that transcript levels of rln3a, rln3b, and rln in the brain changed significantly after seawater transfer. Particularly, rln3b showed different patterns of temporal changes between anadromous and stream-resident morphs. The transcript levels of relaxin family peptide receptors, rxfp1, rxfp2b, rxfp3-2a, and rxfp3-2b, did not exhibit substantial changes in the brain, although these were constantly higher in the anadromous morph than the stream-resident morph. These results suggest that stickleback relaxin systems are differentially regulated by salinity signals, at least at the transcriptional level, and anadromous and stream-resident morphs differ in relaxin signaling pathways. The differences in the expression of relaxin-related genes between these two morphs provide a foundation for further exploration of the osmoregulatory function of relaxins in teleosts.
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Affiliation(s)
- Makoto Kusakabe
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba 277-8564, Japan.
| | - Asano Ishikawa
- Ecological Genetics Laboratory, National Institute of Genetics, Shizuoka 411-8540, Japan
| | - Jun Kitano
- Ecological Genetics Laboratory, National Institute of Genetics, Shizuoka 411-8540, Japan
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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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Kong RCK, Bathgate RAD, Bruell S, Wade JD, Gooley PR, Petrie EJ. Mapping Key Regions of the RXFP2 Low-Density Lipoprotein Class-A Module That Are Involved in Signal Activation. Biochemistry 2014; 53:4537-48. [DOI: 10.1021/bi500797d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Roy C. K. Kong
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular
Science and Biotechnology Institute, ‡Florey Institute of Neuroscience
and Mental Health, and §School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ross A. D. Bathgate
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular
Science and Biotechnology Institute, ‡Florey Institute of Neuroscience
and Mental Health, and §School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Shoni Bruell
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular
Science and Biotechnology Institute, ‡Florey Institute of Neuroscience
and Mental Health, and §School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - John D. Wade
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular
Science and Biotechnology Institute, ‡Florey Institute of Neuroscience
and Mental Health, and §School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Paul R. Gooley
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular
Science and Biotechnology Institute, ‡Florey Institute of Neuroscience
and Mental Health, and §School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Emma J. Petrie
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular
Science and Biotechnology Institute, ‡Florey Institute of Neuroscience
and Mental Health, and §School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
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68
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Wang XY, Guo YQ, Zhang WJ, Shao XX, Liu YL, Xu ZG, Guo ZY. The electrostatic interactions of relaxin-3 with receptor RXFP4 and the influence of its B-chain C-terminal conformation. FEBS J 2014; 281:2927-36. [PMID: 24802387 DOI: 10.1111/febs.12830] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 04/24/2014] [Accepted: 05/01/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Xin-Yi Wang
- Institute of Protein Research; College of Life Sciences and Technology; Tongji University; Shanghai China
- Central Laboratory; Shanghai East Hospital; Tongji University School of Medicine; China
| | - Yu-Qi Guo
- Institute of Protein Research; College of Life Sciences and Technology; Tongji University; Shanghai China
| | - Wei-Jie Zhang
- 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
| | - Ya-Li Liu
- Central Laboratory; Shanghai East Hospital; Tongji University School of Medicine; China
| | - Zeng-Guang Xu
- Central Laboratory; Shanghai East Hospital; Tongji University School of Medicine; China
| | - Zhan-Yun Guo
- Institute of Protein Research; College of Life Sciences and Technology; Tongji University; Shanghai China
- Central Laboratory; Shanghai East Hospital; Tongji University School of Medicine; China
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McGowan BM, Minnion JS, Murphy KG, Roy D, Stanley SA, Dhillo WS, Gardiner JV, Ghatei MA, Bloom SR. Relaxin-3 stimulates the neuro-endocrine stress axis via corticotrophin-releasing hormone. J Endocrinol 2014; 221:337-46. [PMID: 24578294 DOI: 10.1530/joe-13-0603] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Relaxin-3 is a member of the insulin superfamily. It is expressed in the nucleus incertus of the brainstem, which has projections to the hypothalamus. Relaxin-3 binds with high affinity to RXFP1 and RXFP3. RXFP3 is expressed within the hypothalamic paraventricular nucleus (PVN), an area central to the stress response. The physiological function of relaxin-3 is unknown but previous work suggests a role in appetite control, stimulation of the hypothalamic-pituitary-gonadal axis and stress. Central administration of relaxin-3 induces c-fos expression in the PVN and increases plasma ACTH levels in rats. The aim of this study was to investigate the effect of central administration of human relaxin-3 (H3) on the hypothalamic-pituitary-adrenal (HPA) axis in male rodents in vivo and in vitro. Intracerebroventricular (i.c.v) administration of H3 (5 nmol) significantly increased plasma corticosterone at 30 min following injection compared with vehicle. Intra-PVN administration of H3 (1.8-1620 pmol) significantly increased plasma ACTH at 1620 pmol H3 and corticosterone at 180-1620 pmol H3 at 30 min following injection compared with vehicle. The stress hormone prolactin was also significantly raised at 15 min post-injection compared with vehicle. Treatment of hypothalamic explants with H3 (10-1000 nM) stimulated the release of corticotrophin-releasing hormone (CRH) and arginine vasopressin (AVP), but H3 had no effect on the release of ACTH from in vitro pituitary fragments. These results suggest that relaxin-3 may regulate the HPA axis, via hypothalamic CRH and AVP neurons. Relaxin-3 may act as a central signal linking nutritional status, reproductive function and stress.
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Affiliation(s)
- B M McGowan
- Department of Diabetes and Endocrinology, Guy's and St Thomas' NHS Foundation Trust, Westminster Bridge Road, London SE1 7EH, London Section of Investigative Medicine, Department of Medicine, Imperial College London, 6th Floor Commonwealth Building, Hammersmith Campus, Du Cane Road, London W12 ONN, UK Molecular Genetics, Rockefeller University, New York, NY 10065, USA
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Zhang WJ, Wang XY, Guo YQ, Luo X, Gao XJ, Shao XX, Liu YL, Xu ZG, Guo ZY. The highly conserved negatively charged Glu141 and Asp145 of the G-protein-coupled receptor RXFP3 interact with the highly conserved positively charged arginine residues of relaxin-3. Amino Acids 2014; 46:1393-402. [DOI: 10.1007/s00726-014-1705-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 02/20/2014] [Indexed: 10/25/2022]
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Lodhi RSZ, Nakabayashi K, Suzuki K, Yamada AY, Hazama R, Ebina Y, Yamada H. Relaxin has anti-apoptotic effects on human trophoblast-derived HTR-8/SV neo cells. Gynecol Endocrinol 2013; 29:1051-4. [PMID: 24070111 DOI: 10.3109/09513590.2013.829444] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The study was conducted to evaluate the effects of human relaxin on apoptosis in the human trophoblast derived HTR-8/SV neo cell line, which is a possible model of human extravillous trophoblasts (EVTs). HTR-8/SV neo cells, cultured in phenol red free RPMI1640 medium, were treated with different doses of human recombinant (rH2) relaxin in serum-deprived conditions. RT-PCR was used for evaluating relaxin receptor: RXFP1 and RXFP2 expression in HTR-8/SV neo cells. The cell death was examined by TUNEL assay. Furthermore, we investigated caspase-3, cleaved PARP and Bcl-2 expressions by Western blot analysis to recognize the translational effects of anti-apoptotic and pro-apoptotic proteins. RXFP1 and RXFP2 mRNA expression was observed in HTR-8/SV neo cells. Compared with untreated control cultures, treatment with rH2 relaxin, decreased TUNEL-positive rate in HTR-8/SV neo cells was observed. Western blot analysis revealed that treatment with rH2 relaxin decreased the expression of caspase-3 and cleaved PARP, but in contrast increased Bcl-2 expression in those cells. These results suggest that rH2 relaxin has anti-apoptotic effects on HTR8/SV neo cells by decreasing pro-apoptotic caspase-3 and cleaved PARP expression and up-regulating anti-apoptotic Bcl-2 expression.
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Affiliation(s)
- Romana S Z Lodhi
- Department of Obstetrics and Gynecology, Kobe University Graduate School of Medicine , Kobe , Japan
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Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Spedding M, Peters JA, Harmar AJ. The Concise Guide to PHARMACOLOGY 2013/14: G protein-coupled receptors. Br J Pharmacol 2013; 170:1459-581. [PMID: 24517644 PMCID: PMC3892287 DOI: 10.1111/bph.12445] [Citation(s) in RCA: 505] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. G protein-coupled receptors are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates.
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Affiliation(s)
- Stephen PH Alexander
- School of Life Sciences, University of Nottingham Medical SchoolNottingham, NG7 2UH, UK
| | - Helen E Benson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Elena Faccenda
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Adam J Pawson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Joanna L Sharman
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | | | - John A Peters
- Neuroscience Division, Medical Education Institute, Ninewells Hospital and Medical School, University of DundeeDundee, DD1 9SY, UK
| | - Anthony J Harmar
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
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Ganella DE, Ma S, Gundlach AL. Relaxin-3/RXFP3 Signaling and Neuroendocrine Function - A Perspective on Extrinsic Hypothalamic Control. Front Endocrinol (Lausanne) 2013; 4:128. [PMID: 24065955 PMCID: PMC3776160 DOI: 10.3389/fendo.2013.00128] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 09/02/2013] [Indexed: 01/08/2023] Open
Abstract
Complex neural circuits within the hypothalamus that govern essential autonomic processes and associated behaviors signal using amino acid and monoamine transmitters and a variety of neuropeptide (hormone) modulators, often via G-protein coupled receptors (GPCRs) and associated cellular pathways. Relaxin-3 is a recently identified neuropeptide that is highly conserved throughout evolution. Neurons expressing relaxin-3 are located in the brainstem, but broadly innervate the entire limbic system including the hypothalamus. Extensive anatomical data in rodents and non-human primate, and recent regulatory and functional data, suggest relaxin-3 signaling via its cognate GPCR, RXFP3, has a broad range of effects on neuroendocrine function associated with stress responses, feeding and metabolism, motivation and reward, and possibly sexual behavior and reproduction. Therefore, this article aims to highlight the growing appreciation of the relaxin-3/RXFP3 system as an important "extrinsic" regulator of the neuroendocrine axis by reviewing its neuroanatomy and its putative roles in arousal-, stress-, and feeding-related behaviors and links to associated neural substrates and signaling networks. Current evidence identifies RXFP3 as a potential therapeutic target for treatment of neuroendocrine disorders and related behavioral dysfunction.
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Affiliation(s)
- Despina E. Ganella
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Andrew L. Gundlach
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC, Australia
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74
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Translational profiling of cardiomyocytes identifies an early Jak1/Stat3 injury response required for zebrafish heart regeneration. Proc Natl Acad Sci U S A 2013; 110:13416-21. [PMID: 23901114 DOI: 10.1073/pnas.1309810110] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Certain lower vertebrates like zebrafish activate proliferation of spared cardiomyocytes after cardiac injury to regenerate lost heart muscle. Here, we used translating ribosome affinity purification to profile translating RNAs in zebrafish cardiomyocytes during heart regeneration. We identified dynamic induction of several Jak1/Stat3 pathway members following trauma, events accompanied by cytokine production. Transgenic Stat3 inhibition in cardiomyocytes restricted injury-induced proliferation and regeneration, but did not reduce cardiogenesis during animal growth. The secreted protein Rln3a was induced in a Stat3-dependent manner by injury, and exogenous Rln3 delivery during Stat3 inhibition stimulated cardiomyocyte proliferation. Our results identify an injury-specific cardiomyocyte program essential for heart regeneration.
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75
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Nakazawa CM, Shikata K, Uesugi M, Katayama H, Aoshima K, Tahara K, Takahashi E, Hida T, Shibata H, Ogura H, Seiki T, Oda Y, Kuromitsu J, Miyamoto N. Prediction of relaxin-3-induced downstream pathway resulting in anxiolytic-like behaviors in rats based on a microarray and peptidome analysis. J Recept Signal Transduct Res 2013; 33:224-33. [PMID: 23697547 DOI: 10.3109/10799893.2012.756895] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The effect of the intracerebroventricular (i.c.v.) injection of relaxin-3 (RLX3) was evaluated using anxiety-related behavioral tests in rats. RLX3-injected animals showed normal locomotion activity in a habituated environment and declined anxiety cognition in the elevated plus maze test and the shock probe-burying test. The measurement of spontaneous locomotor activity in a novel environment also suggested that RLX3 reduced the stress response. To elucidate the regulatory mechanisms of the downstream signaling pathways underlying RLX3 activity and its relation to anxiolytic and hyperphagic behavior phenotypes, RLX3-i.c.v.-injected rat hypothalamic responses were examined using a microarray analysis. Ingenuity Pathway Analysis software listed the phenotype-relating genes and they showed characteristic expression patterns in the rat hypothalamus. When peptidome data sets for the same listed genes was analyzed using a semi-quantitative approach, the expressions of two neuropeptides were found to have increased. One of these neuropeptides, oxytocin (Oxt), exhibited increased expression in both the microarray and the peptidomic analysis, and a Western blot analysis validated the mass spectrometry results. A cross-omics data analysis is useful for predicting downstream signaling pathways, and the anxiolytic-like behavior of RLX3 may be mediated by an oxytocin signaling pathway in rats. These results suggest that RLX3 acts as an anxiolytic peptide and that the downstream pathways mediated by its receptors may be potential candidates for the treatment of anxieties in the future.
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Affiliation(s)
- Chihiro Miyamoto Nakazawa
- KAN Product Creation Unit, Eisai Product Creation Systems, Eisai Co., Ltd., Tsukuba, Ibaraki, Japan.
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76
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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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77
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Chemical synthesis and orexigenic activity of rat/mouse relaxin-3. Amino Acids 2013; 44:1529-36. [PMID: 23456488 DOI: 10.1007/s00726-013-1478-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 02/18/2013] [Indexed: 10/27/2022]
Abstract
The insulin-like peptide, relaxin-3 was first identified just a decade ago via a genomic database search and is now recognized to be a key neuropeptide with several roles including the regulation of arousal, stress responses and neuroendocrine homeostasis. It also has significant potential as a drug to treat stress and obesity. Its actions are mediated via its cognate G protein-coupled receptor, RXFP3, which is found in abundant numbers in the brain. However, much remains to be determined with respect to the mechanism of neurological action of this peptide. Consequently, the chemical synthesis of the rat and mouse (which share identical primary structures) two-chain, three disulfide peptide was undertaken and the resulting peptide subjected to detailed in vitro and in vivo assay. Use of efficient solid-phase synthesis methods provided the two regioselectively S-protected A- and B-chains which were readily combined via sequential disulfide bond formation. The synthetic rat/mouse relaxin-3 was obtained in high purity and good overall yield. It demonstrated potent orexigenic activity in rats in that central intracerebroventricular infusion led to significantly increased food intake and water drinking.
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78
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Bathgate RAD, Halls ML, van der Westhuizen ET, Callander GE, Kocan M, Summers RJ. Relaxin family peptides and their receptors. Physiol Rev 2013; 93:405-80. [PMID: 23303914 DOI: 10.1152/physrev.00001.2012] [Citation(s) in RCA: 376] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
There are seven relaxin family peptides that are all structurally related to insulin. Relaxin has many roles in female and male reproduction, as a neuropeptide in the central nervous system, as a vasodilator and cardiac stimulant in the cardiovascular system, and as an antifibrotic agent. Insulin-like peptide-3 (INSL3) has clearly defined specialist roles in male and female reproduction, relaxin-3 is primarily a neuropeptide involved in stress and metabolic control, and INSL5 is widely distributed particularly in the gastrointestinal tract. Although they are structurally related to insulin, the relaxin family peptides produce their physiological effects by activating a group of four G protein-coupled receptors (GPCRs), relaxin family peptide receptors 1-4 (RXFP1-4). Relaxin and INSL3 are the cognate ligands for RXFP1 and RXFP2, respectively, that are leucine-rich repeat containing GPCRs. RXFP1 activates a wide spectrum of signaling pathways to generate second messengers that include cAMP and nitric oxide, whereas RXFP2 activates a subset of these pathways. Relaxin-3 and INSL5 are the cognate ligands for RXFP3 and RXFP4 that are closely related to small peptide receptors that when activated inhibit cAMP production and activate MAP kinases. Although there are still many unanswered questions regarding the mode of action of relaxin family peptides, it is clear that they have important physiological roles that could be exploited for therapeutic benefit.
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Affiliation(s)
- R A D Bathgate
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences & Department of Pharmacology, Monash University, Victoria, Australia
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79
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Bathgate RAD, Oh MHY, Ling WJJ, Kaas Q, Hossain MA, Gooley PR, Rosengren KJ. Elucidation of relaxin-3 binding interactions in the extracellular loops of RXFP3. Front Endocrinol (Lausanne) 2013; 4:13. [PMID: 23440673 PMCID: PMC3579193 DOI: 10.3389/fendo.2013.00013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 01/31/2013] [Indexed: 12/28/2022] Open
Abstract
Relaxin-3 is a highly conserved neuropeptide in vertebrate species and binds to the Class A G protein-coupled receptor (GPCR) RXFP3. Relaxin-3 is involved in a wide range of behaviors, including feeding, stress responses, arousal, and cognitive processes and therefore targeting of RXFP3 may be relevant for a range of neurological diseases. Structural knowledge of RXFP3 and its interaction with relaxin-3 would both increase our understanding of ligand recognition in GPCRs that respond to protein ligands and enable acceleration of the design of drug leads. In this study we have used comparative sequence analysis, molecular modeling and receptor mutagenesis to investigate the binding site of the native ligand human relaxin-3 (H3 relaxin) on the human RXFP3 receptor. Previous structure function studies have demonstrated that arginine residues in the H3 relaxin B-chain are critical for binding interactions with the receptor extracellular loops and/or N-terminal domain. Hence we have concentrated on determining the ligand interacting sites in these domains and have focused on glutamic (E) and aspartic acid (D) residues in these regions that may form electrostatic interactions with these critical arginine residues. Conserved D/E residues identified from vertebrate species multiple sequence alignments were mutated to Ala in human RXFP3 to test the effect of loss of amino acid side chain on receptor binding using a Eu-labeled relaxin-3 agonist. Finally data from mutagenesis experiments have been used in ligand docking simulations to a homology model of human RXFP3 based on the peptide-bound chemokine receptor 4 (CXCR4) structure. These studies have resulted in a model of the relaxin-3 interaction with RXFP3 which will inform further interrogation of the agonist binding site.
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Affiliation(s)
- Ross A. D. Bathgate
- Florey Institute of Neuroscience and Mental Health, University of MelbourneParkville, VIC, Australia
- Department of Biochemistry and Molecular Biology, University of MelbourneParkville, VIC, Australia
- *Correspondence: Ross A. D. Bathgate, Florey Institute of Neuroscience and Mental Health, University of Melbourne, 3010 Victoria, Australia. e-mail:
| | - Maria H. Y. Oh
- Florey Institute of Neuroscience and Mental Health, University of MelbourneParkville, VIC, Australia
- Department of Biochemistry and Molecular Biology, University of MelbourneParkville, VIC, Australia
| | - W. J. Jason Ling
- Florey Institute of Neuroscience and Mental Health, University of MelbourneParkville, VIC, Australia
- Department of Biochemistry and Molecular Biology, University of MelbourneParkville, VIC, Australia
| | - Quentin Kaas
- Institute for Molecular Bioscience, The University of QueenslandBrisbane, QLD, Australia
| | - M. Akhter Hossain
- Florey Institute of Neuroscience and Mental Health, University of MelbourneParkville, VIC, Australia
- School of Chemistry, University of MelbourneParkville, VIC, Australia
| | - Paul R. Gooley
- Department of Biochemistry and Molecular Biology, University of MelbourneParkville, VIC, Australia
| | - K. Johan Rosengren
- School of Biomedical Sciences, The University of QueenslandBrisbane, QLD, Australia
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80
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Xiao J, Huang Z, Chen CZ, Agoulnik IU, Southall N, Hu X, Jones RE, Ferrer M, Zheng W, Agoulnik AI, Marugan JJ. Identification and optimization of small-molecule agonists of the human relaxin hormone receptor RXFP1. Nat Commun 2013; 4:1953. [PMID: 23764525 PMCID: PMC4915074 DOI: 10.1038/ncomms2953] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 04/29/2013] [Indexed: 11/09/2022] Open
Abstract
The anti-fibrotic, vasodilatory and pro-angiogenic therapeutic properties of recombinant relaxin peptide hormone have been investigated in several diseases, and recent clinical trial data has shown benefit in treating acute heart failure. However, the remodelling capacity of these peptide hormones is difficult to study in chronic settings because of their short half-life and the need for intravenous administration. Here we present the first small-molecule series of human relaxin/insulin-like family peptide receptor 1 agonists. These molecules display similar efficacy as the natural hormone in several functional assays. Mutagenesis studies indicate that the small molecules activate relaxin receptor through an allosteric site. These compounds have excellent physical and in vivo pharmacokinetic properties to support further investigation of relaxin biology and animal efficacy studies of the therapeutic benefits of relaxin/insulin-like family peptide receptor 1 activation.
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Affiliation(s)
- Jingbo Xiao
- NIH Chemical Genomics Center, Discovery Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, USA
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81
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Bruell S, Kong RCK, Petrie EJ, Hoare B, Wade JD, Scott DJ, Gooley PR, Bathgate RAD. Chimeric RXFP1 and RXFP2 Receptors Highlight the Similar Mechanism of Activation Utilizing Their N-Terminal Low-Density Lipoprotein Class A Modules. Front Endocrinol (Lausanne) 2013; 4:171. [PMID: 24273532 PMCID: PMC3822782 DOI: 10.3389/fendo.2013.00171] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 10/25/2013] [Indexed: 11/13/2022] Open
Abstract
Relaxin family peptide (RXFP) receptors 1 and 2 are unique G-protein coupled receptors in that they contain an N-terminal low-density lipoprotein type A (LDLa) module which is necessary for receptor activation. The current hypothesis suggests that upon ligand binding the LDLa module interacts with the transmembrane (TM) domain of a homodimer partner receptor to induce the active receptor conformations. We recently demonstrated that three residues in the N-terminus of the RXFP1 LDLa module are potentially involved in hydrophobic interactions with the receptor to drive activation. RXFP2 shares two out of three of the residues implicated, suggesting that the two LDLa modules could be interchanged without adversely affecting activity. However, in 2007 it was shown that a chimera consisting of the RXFP1 receptor with its LDLa swapped for that of RXFP2 did not signal. We noticed this construct also contained the RXFP2 region linking the LDLa to the leucine-rich repeats. We therefore constructed chimeric RXFP1 and RXFP2 receptors with their LDLa modules swapped immediately C-terminally to the final cysteine residue of the module, retaining the native linker. In addition, we exchanged the TM domains of the chimeras to explore if matching the LDLa module with the TM domain of its native receptor altered activity. All of the chimeras were expressed at the surface of HEK293T cells with ligand binding profiles similar to the wild-type receptors. Importantly, as predicted, ligand binding was able to induce cAMP-based signaling. Chimeras of RXFP1 with the LDLa of RXFP2 demonstrated reduced H2 relaxin potency with the pairing of the RXFP2 TM with the RXFP2 LDLa necessary for full ligand efficacy. In contrast the ligand-mediated potencies and efficacies on the RXFP2 chimeras were similar suggesting the RXFP1 LDLa module has similar efficacy on the RXFP2 TM domain. Our studies demonstrate the LDLa modules of RXFP1 and RXFP2 modulate receptor activation via a similar mechanism.
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Affiliation(s)
- Shoni Bruell
- Florey Department of Neuroscience and Mental Health, Florey Institute of Neuroscience and Mental Health , Melbourne, VIC , Australia ; Department of Biochemistry and Molecular Biology , Melbourne, VIC , Australia
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82
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Chen CZ, Southall N, Xiao J, Marugan JJ, Ferrer M, Hu X, Jones RE, Feng S, Agoulnik IU, Zheng W, Agoulnik AI. Identification of small-molecule agonists of human relaxin family receptor 1 (RXFP1) by using a homogenous cell-based cAMP assay. ACTA ACUST UNITED AC 2012; 18:670-7. [PMID: 23212924 DOI: 10.1177/1087057112469406] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The relaxin hormone is involved in a variety of biological functions, including female reproduction and parturition, as well as regulation of cardiovascular, renal, pulmonary, and hepatic functions. It regulates extracellular matrix remodeling, cell invasiveness, proliferation, differentiation, and overall tissue homeostasis. The G protein-coupled receptor (GPCR) relaxin family receptor 1 (RXFP1) is a cognate relaxin receptor that mainly signals through cyclic AMP second messenger. Although agonists of the receptor could have a wide range of pharmacologic utility, until now there have been no reported small-molecule agonists for relaxin receptors. Here, we report the development of a quantitative high-throughput platform for an RXFP1 agonist screen based on homogenous cell-based HTRF cyclic AMP (cAMP) assay technology. Two small molecules of similar structure were independently identified from a screen of more than 365 677 compounds. Neither compound showed activity in a counterscreen with HEK293T cells transfected with an unrelated GPCR vasopressin 1b receptor. These small-molecule agonists also demonstrated selectivity against the RXFP2 receptor, providing a basis for future medicinal chemistry optimization of selective relaxin receptor agonists.
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Affiliation(s)
- Catherine Z Chen
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, USA
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83
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Ganella DE, Callander GE, Ma S, Bye CR, Gundlach AL, Bathgate RAD. Modulation of feeding by chronic rAAV expression of a relaxin-3 peptide agonist in rat hypothalamus. Gene Ther 2012; 20:703-16. [PMID: 23135160 DOI: 10.1038/gt.2012.83] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 08/30/2012] [Accepted: 09/20/2012] [Indexed: 11/09/2022]
Abstract
Relaxin-3 is a neuropeptide that is abundantly expressed by discrete brainstem neuron populations that broadly innervate forebrain areas rich in the relaxin-3 G-protein-coupled-receptor, RXFP3. Acute and subchronic central administration of synthetic relaxin-3 or an RXFP3-selective agonist peptide, R3/I5, increase feeding and body weight in rats. Intrahypothalamic injection of relaxin-3 also increases feeding. In this study, we developed a recombinant adeno-associated virus 1/2 (rAAV1/2) vector that drives expression and constitutive secretion of bioactive R3/I5 and assessed the effect of intrahypothalamic injections on daily food intake and body weight gain in adult male rats over 8 weeks. In vitro testing revealed that the vector rAAV1/2-fibronectin (FIB)-R3/I5 directs the constitutive secretion of bioactive R3/I5 peptide. Bilateral injection of rAAV1/2-FIB-R3/I5 vector into the paraventricular nucleus produced an increase in daily food intake and body weight gain (P<0.01, ~23%, respectively), relative to control treatment. In a separate cohort of rats, quantitative polymerase chain reaction analysis of hypothalamic mRNA revealed strong expression of R3/I5 transgene at 3 months post-rAAV1/2-FIB-R3/I5 infusion. Levels of mRNA transcripts for the relaxin-3 receptor RXFP3, the hypothalamic 'feeding' peptides neuropeptide Y, AgRP and POMC, and the reproductive hormone, GnRH, were all similar to control, whereas vasopressin and oxytocin (OT) mRNA levels were reduced by ~25% (P=0.051) and ~50% (P<0.005), respectively, in rAAV1/2-FIB-R3/I5-treated rats (at 12 weeks, n=9/8 rats per group). These data demonstrate for the first time that R3/I5 is effective in modulating feeding in the rat by chronic hypothalamic RXFP3 activation and suggest a potential underlying mechanism involving altered OT signalling. Importantly, there was no desensitization of the feeding response over the treatment period and no apparent deleterious health effects, indicating that targeting the relaxin-3-RXFP3 system may be an effective long-term therapy for eating disorders.
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Affiliation(s)
- D E Ganella
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia
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84
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Civelli O, Reinscheid RK, Zhang Y, Wang Z, Fredriksson R, Schiöth HB. G protein-coupled receptor deorphanizations. Annu Rev Pharmacol Toxicol 2012; 53:127-46. [PMID: 23020293 PMCID: PMC5828024 DOI: 10.1146/annurev-pharmtox-010611-134548] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
G protein-coupled receptors (GPCRs) are major regulators of intercellular interactions. They initiate these actions by being activated by a wide variety of natural ligands. Historically, ligands were discovered first, but the advent of molecular biology reversed this trend. Most GPCRs are identified on the basis of their DNA sequences and thus are initially unmatched to known natural ligands. They are termed orphan GPCRs. Discovering their ligands-i.e., "deorphanizing" the GPCRs-gave birth to the field of reverse pharmacology. This review discusses the present status of GPCR deorphanization, presents a few examples of successes and surprises, and highlights difficulties encountered in these efforts.
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Affiliation(s)
- Olivier Civelli
- Department of Pharmacology, University of California, Irvine, Irvine, California 92617, USA.
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85
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Chan LJ, Rosengren KJ, Layfield SL, Bathgate RAD, Separovic F, Samuel CS, Hossain MA, Wade JD. Identification of key residues essential for the structural fold and receptor selectivity within the A-chain of human gene-2 (H2) relaxin. J Biol Chem 2012; 287:41152-64. [PMID: 23024363 DOI: 10.1074/jbc.m112.409284] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human gene-2 (H2) relaxin is currently in Phase III clinical trials for the treatment of acute heart failure. It is a 53-amino acid insulin-like peptide comprising two chains and three disulfide bonds. It interacts with two of the relaxin family peptide (RXFP) receptors. Although its cognate receptor is RXFP1, it is also able to cross-react with RXFP2, the native receptor for a related peptide, insulin-like peptide 3. In order to understand the basis of this cross-reactivity, it is important to elucidate both binding and activation mechanisms of this peptide. The primary binding mechanism of this hormone has been extensively studied and well defined. H2 relaxin binds to the leucine-rich repeats of RXFP1 and RXFP2 using B-chain-specific residues. However, little is known about the secondary interaction that involves the A-chain of H2 relaxin and transmembrane exoloops of the receptors. We demonstrate here through extensive mutation of the A-chain that the secondary interaction between H2 relaxin and RXFP1 is not driven by any single amino acid, although residues Tyr-3, Leu-20, and Phe-23 appear to contribute. Interestingly, these same three residues are important drivers of the affinity and activity of H2 relaxin for RXFP2 with additional minor contributions from Lys-9, His-12, Lys-17, Arg-18, and Arg-22. Our results provide new insights into the mechanism of secondary activation interaction of RXFP1 and RXFP2 by H2 relaxin, leading to a potent and RXFP1-selective analog, H2:A(4-24)(F23A), which was tested in vitro and in vivo and found to significantly inhibit collagen deposition similar to native H2 relaxin.
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Affiliation(s)
- Linda J Chan
- Florey Neuroscience Institutes, University of Melbourne, Victoria 3010, Australia
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86
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Scott DJ, Rosengren KJ, Bathgate RAD. The different ligand-binding modes of relaxin family peptide receptors RXFP1 and RXFP2. Mol Endocrinol 2012; 26:1896-906. [PMID: 22973049 DOI: 10.1210/me.2012-1188] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Relaxin and insulin-like peptide 3 (INSL3) are peptide hormones with a number of important physiological roles in reproduction, regulation of extracellular matrix turnover, and cardiovascular function. Relaxin and INSL3 mediate their actions through the closely related G-protein coupled receptors, relaxin family peptide receptors 1 and 2 (RXFP1 and RXFP2), respectively. These receptors have large extracellular domains (ECD) that contain high-affinity ligand-binding sites within their 10 leucine-rich repeat (LRR)-containing modules. Although relaxin can bind and activate both RXFP1 and RXFP2, INSL3 can only bind and activate RXFP2. To investigate whether this difference is related to the nature of the high-affinity ECD binding site or to differences in secondary binding sites involving the receptor transmembrane (TM) domain, we created a suite of constructs with RXFP1/2 chimeric ECD attached to single TM helices. We show that by changing as little as one LRR, representing four amino acid substitutions, we were able to engineer a high-affinity INSL3-binding site into the ECD of RXFP1. Molecular modeling of the INSL3-RXFP2 interaction based on extensive experimental data highlights the differences in the binding mechanisms of relaxin and INSL3 to the ECD of their cognate receptors. Interestingly, when the engineered RXFP1/2 ECD were introduced into full-length RXFP1 constructs, INSL3 exhibited only low affinity and efficacy on these receptors. These results highlight critical differences both in the ECD binding and in the coordination of the ECD-binding site with the TM domain, and provide new mechanistic insights into the binding and activation events of RXFP1 and RXFP2 by their native hormone ligands.
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Affiliation(s)
- Daniel J Scott
- Florey Neuroscience Institutes and the Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria 3010, Australia
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87
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Halls ML. Constitutive formation of an RXFP1-signalosome: a novel paradigm in GPCR function and regulation. Br J Pharmacol 2012; 165:1644-1658. [PMID: 21557732 DOI: 10.1111/j.1476-5381.2011.01470.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The classical second messenger cAMP is important in diverse physiological processes, where its spatial and temporal compartmentalization allows precise control over multiple cellular events. Within this context, G-protein-coupled receptors (GPCRs) govern specialized pools of cAMP, which are functionally specific for the unique cellular effects attributed to a particular system. The relaxin receptor, RXFP1, is a GPCR that exerts pleiotropic physiological effects including a potent anti-fibrotic response, increased cancer metastases, and has efficacy as a vasodilator in heart failure. On a cellular level, relaxin stimulation of RXFP1 results in the activation of multiple G-protein pathways affecting cAMP accumulation. Specificity and diversity in the cAMP signal generated by RXFP1 is controlled by differential G-protein coupling dependent upon the background of cellular expression, and cAMP compartmentalization. Further complexity in cAMP signalling results from the constitutive assembly of an RXFP1-signalosome, which specifically responds to low concentrations of relaxin, and activates a distinct cAMP pathway. The RXFP1-signalosome is a higher-order protein complex that facilitates receptor sensitivity to attomolar concentration of peptide, exhibits constitutive activity and dual coupling to G-proteins and β-arrestins and reveals a concentration-biased agonism mediated by relaxin. The specific and directed formation of GPCR-centered signalosomes allows an even greater spatial and temporal control of cAMP, thus rationalizing the considerable physiological scope of this ubiquitous second messenger.
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Affiliation(s)
- Michelle L Halls
- Department of Pharmacology, University of Cambridge, Cambridge, UK
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88
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Hossain MA, Wade JD, Bathgate RAD. Chimeric relaxin peptides highlight the role of the A-chain in the function of H2 relaxin. Peptides 2012; 35:102-6. [PMID: 22414484 DOI: 10.1016/j.peptides.2012.02.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 02/23/2012] [Accepted: 02/24/2012] [Indexed: 11/25/2022]
Abstract
Human gene-2 (H2) relaxin is a member of the insulin-relaxin peptide superfamily. Because of the potential clinical applications of H2 relaxin, there is a need for novel analogs that have improved biological activity and receptor specificity. In this respect, we have chemically assembled chimeric peptides consisting of the B-chain of H2 relaxin in combination with A-chains from other insulin/relaxin family members. The peptides were prepared using solid phase peptide synthesis together with regioselective disulfide bond formation and characterized by RP-HPLC, MALDI-TOF MS and amino acid analysis. Their in vitro activity was assessed in RXFP1 or RXFP2 expressing cells. Replacement of the H2 relaxin A-chain resulted in parallel losses of binding affinity and activity on RXFP1. Not surprisingly H1A-H2B demonstrated the highest activity as the H1 A-chain shares high homology with H2 relaxin whereas INSLA-H2B, which shows low homology, had very poor activity. Importantly A-chain replacements had a dramatic effect on RXFP2 activity similar to previous results demonstrating different modes of activation of A-chain variants on RXFP1 and RXFP2. H3A-H2B is particularly interesting as it displays moderate activity at RXFP1 but poor activity at RXFP2 indicating that it may be a template for specific RXFP1 agonist development. Our study confirms that the activity of H2 relaxin at both RXFP1 and RXFP2 relies on interactions with both the B- and A-chains, and also provide new biochemical insights into the mechanism of relaxin action that the A-chain needs to be in native or near-native form for strong RXFP1 or RXFP2 agonist activity.
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89
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Shabanpoor F, Bathgate RA, Belgi A, Chan LJ, Nair VB, Wade JD, Hossain MA. Site-specific conjugation of a lanthanide chelator and its effects on the chemical synthesis and receptor binding affinity of human relaxin-2 hormone. Biochem Biophys Res Commun 2012; 420:253-6. [DOI: 10.1016/j.bbrc.2012.02.141] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 02/24/2012] [Indexed: 12/24/2022]
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90
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Shabanpoor F, Akhter Hossain M, Ryan PJ, Belgi A, Layfield S, Kocan M, Zhang S, Samuel CS, Gundlach AL, Bathgate RAD, Separovic F, Wade JD. Minimization of human relaxin-3 leading to high-affinity analogues with increased selectivity for relaxin-family peptide 3 receptor (RXFP3) over RXFP1. J Med Chem 2012; 55:1671-81. [PMID: 22257012 DOI: 10.1021/jm201505p] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Relaxin-3 is a neuropeptide that is implicated in the regulation of stress responses and memory. The elucidation of its precise physiological role(s) has, however, been hampered by cross-activation of the relaxin-2 receptor, RXFP1, in the brain. The current study undertook to develop analogues of human relaxin-3 (H3 relaxin) that can selectively bind and activate its receptor, RXFP3. We developed a high-affinity selective agonist (analogue 2) by removal of the intra-A chain disulfide bond and deletion of 10 residues from the N terminus of the A chain. Further truncation of this analogue from the C terminus of the B chain to Cys(B22) and addition of an Arg(B23) led to a high-affinity, RXFP3-selective, competitive antagonist (analogue 3). Central administration of analogue 2 in rats increased food intake, which was blocked by prior coadministration of analogue 3. These novel RXFP3-selective peptides represent valuable pharmacological tools to study the physiological roles of H3 relaxin/RXFP3 systems in the brain and important leads for the development of novel compounds for the treatment of affective and cognitive disorders.
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Affiliation(s)
- Fazel Shabanpoor
- Florey Neuroscience Institutes, The University of Melbourne, Victoria 3010, Australia
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91
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Bathgate RAD, Zhang S, Hughes RA, Rosengren KJ, Wade JD. The structural determinants of insulin-like Peptide 3 activity. Front Endocrinol (Lausanne) 2012; 3:11. [PMID: 22654853 PMCID: PMC3356098 DOI: 10.3389/fendo.2012.00011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 01/12/2012] [Indexed: 11/24/2022] Open
Abstract
Insulin-like peptide 3 (INSL3) is a hormone and/or paracrine factor which is a member of the relaxin peptide family. It has key roles as a fertility regulator in both males and females. The receptor for INSL3 is the leucine rich repeat (LRR) containing G-protein coupled receptor 8 (LGR8) which is now known as relaxin family peptide receptor 2 (RXFP2). Receptor activation by INSL3 involves binding to the LRRs in the large ectodomain of RXFP2 by residues within the B-chain of INSL3 as well as an interaction with the transmembrane exoloops of the receptor. Although the binding to the LRRs is well characterized the features of the peptide and receptor involved in the exoloop interaction are currently unknown. This study was designed to determine the key INSL3 determinants for RXFP2 activation. A chimeric peptide approach was first utilized to demonstrate that the A-chain is critical for receptor activation. Replacement of the INSL3 A-chain with that from the related peptides INSL5 and INSL6 resulted in complete loss of activity despite only minor changes in binding affinity. Subsequent replacement of specific A-chain residues with those from the INSL5 peptide highlighted that the N-terminus of the A-chain of INSL3 is critical for its activity. Remarkably, replacement of the entire N-terminus with four or five alanine residues resulted in peptides with near native activity suggesting that specific residues are not necessary for activity. Additionally removal of two amino acids at the C-terminus of the A-chain and mutation of Lys-8 in the B-chain also resulted in minor decreases in peptide activity. Therefore we have demonstrated that the activity of the INSL3 peptide is driven predominantly by residues 5-9 in the A-chain, with minor additional contributions from the two C-terminal A-chain residues and Lys-8 in the B-chain. Using this new knowledge, we were able to produce a truncated INSL3 peptide structure which retained native activity, despite having 14 fewer residues than the parent peptide.
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Affiliation(s)
- Ross A. D. Bathgate
- Florey Neuroscience Institutes, University of MelbourneMelbourne, VIC, Australia
- Department of Biochemistry and Molecular Biology, University of MelbourneMelbourne, VIC, Australia
- *Correspondence: Ross A. D. Bathgate and John D. Wade, Florey Neuroscience Institutes, University of Melbourne, Melbourne, VIC 3031, Australia. e-mail: ;
| | - Soude Zhang
- Florey Neuroscience Institutes, University of MelbourneMelbourne, VIC, Australia
| | - Richard A. Hughes
- Department of Pharmacology, University of MelbourneMelbourne, VIC, Australia
| | - K. Johan Rosengren
- School of Biomedical Sciences, The University of QueenslandBrisbane, QLD, Australia
| | - John D. Wade
- Florey Neuroscience Institutes, University of MelbourneMelbourne, VIC, Australia
- School of Chemistry, University of MelbourneMelbourne, VIC, Australia
- *Correspondence: Ross A. D. Bathgate and John D. Wade, Florey Neuroscience Institutes, University of Melbourne, Melbourne, VIC 3031, Australia. e-mail: ;
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92
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Site-specific DOTA/europium-labeling of recombinant human relaxin-3 for receptor-ligand interaction studies. Amino Acids 2011; 43:983-92. [DOI: 10.1007/s00726-011-1164-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 11/17/2011] [Indexed: 10/14/2022]
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93
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Smith CM, Ryan PJ, Hosken IT, Ma S, Gundlach AL. Relaxin-3 systems in the brain—The first 10 years. J Chem Neuroanat 2011; 42:262-75. [DOI: 10.1016/j.jchemneu.2011.05.013] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 05/24/2011] [Accepted: 05/29/2011] [Indexed: 12/25/2022]
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94
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Relaxin increases human endothelial progenitor cell NO and migration and vasculogenesis in mice. Blood 2011; 119:629-36. [PMID: 22028476 DOI: 10.1182/blood-2011-04-346007] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The ovarian peptide hormone, relaxin, circulates during pregnancy, contributing to profound maternal vasodilation through endothelial and nitric oxide (NO)-dependent mechanisms. Circulating numbers of bone marrow-derived endothelial cells (BMDECs), which facilitate angiogenesis and contribute to repair of vascular endothelium, increase during pregnancy. Thus, we hypothesized that relaxin enhances BMDEC NO production, circulating numbers, and function. Recombinant human relaxin-2 (rhRLX) stimulated PI3K/Akt B-dependent NO production in human BMDECs within minutes, and activated BMDEC migration that was inhibited by L-N(G)-nitroarginine methyl ester. In BMDECs isolated from relaxin/insulin-like family peptide receptor 2 gene (Rxfp2) knockout and wild-type mice, but not Rxfp1 knockout mice, rhRLX rapidly increased NO production. Similarly, rhRLX increased circulating BMDEC number in Rxfp2 knockout and wild-type mice, but not Rxfp1 knockout mice as assessed by colony formation and flow cytometry. Taken together, these results indicate that relaxin effects BMDEC function through the RXFP1 receptor. Finally, both vascularization and incorporation of GFP-labeled BMDECs were stimulated in rhRLX-impregnated Matrigel pellets implanted in mice. To conclude, relaxin is a novel regulator of BMDECs number and function, which has implications for angiogenesis and vascular remodeling in pregnancy, as well as therapeutic potential in vascular disease.
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95
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Hossain MA, Rosengren KJ, Samuel CS, Shabanpoor F, Chan LJ, Bathgate RAD, Wade JD. The minimal active structure of human relaxin-2. J Biol Chem 2011; 286:37555-65. [PMID: 21878627 DOI: 10.1074/jbc.m111.282194] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
H2 relaxin is a peptide hormone associated with a number of therapeutically relevant physiological effects, including regulation of collagen metabolism and multiple vascular control pathways. It is currently in phase III clinical trials for the treatment of acute heart failure due to its ability to induce vasodilation and influence renal function. It comprises 53 amino acids and is characterized by two separate polypeptide chains (A-B) that are cross-linked by three disulfide bonds. This size and complex structure represents a considerable challenge for the chemical synthesis of H2 relaxin, a major limiting factor for the exploration of modifications and derivatizations of this peptide, to optimize effect and drug-like characteristics. To address this issue, we describe the solid phase peptide synthesis and structural and functional evaluation of 24 analogues of H2 relaxin with truncations at the termini of its peptide chains. We show that it is possible to significantly truncate both the N and C termini of the B-chain while still retaining potent biological activity. This suggests that these regions are not critical for interactions with the H2 relaxin receptor, RXFP1. In contrast, truncations do reduce the activity of H2 relaxin for the related receptor RXFP2 by improving RXFP1 selectivity. In addition to new mechanistic insights into the function of H2 relaxin, this study identifies a critical active core with 38 amino acids. This minimized core shows similar antifibrotic activity as native H2 relaxin when tested in human BJ3 cells and thus represents an attractive receptor-selective lead for the development of novel relaxin therapeutics.
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96
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Donizetti A, Fiengo M, del Gaudio R, Di Giaimo R, Minucci S, Aniello F. Characterization and developmental expression pattern of the relaxin receptor rxfp1 gene in zebrafish. Dev Growth Differ 2011; 52:799-806. [PMID: 21158758 DOI: 10.1111/j.1440-169x.2010.01215.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We report the gene characterization, the cDNA cloning and the temporal and spatial expression pattern of the relaxin receptor rxfp1 gene in the zebrafish Danio rerio. The zebrafish rxfp1 gene has the same syntenic genomic organization, and a similar exon-intron structure to the homologue human gene. Furthermore, the deduced Rxfp1 protein sequence shows a high degree of amino acid similarity when compared with the human protein and the conservation of all amino acid identity necessary for the binding with relaxin. Our results show that rxfp1 gene is active either during embryogenesis or in the adult organism, showing a wide expression pattern. Moreover, we provide the first description of rxfp1 spatial expression pattern during embryo development, showing that the transcript is already present at the early developmental stage and is distributed in all of the embryonic cells until somitogenesis. Starting at the pharyngula stage the gene expression becomes mainly restricted in the brain territories. In fact, at the larval stage, the transcript is detectable in the epiphysis, postoptic region, posterior tuberculum, hypothalamus, optic tectum, tegmentum/pons, medulla and also in the structure of a peripheral nervous system, the terminal nerve. The rxfp1 expression pattern in Danio rerio embryos is very similar to that reported in the adult mammalian brain, suggesting a pivotal role of this receptor in the neurophysiology processes already at very early developmental stages.
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Affiliation(s)
- Aldo Donizetti
- Department of Biological Sciences, University of Naples Federico II, Via Mezzocannone 8, Napoli, Italy
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97
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Campitiello MR, De Franciscis P, Mele D, Izzo G, Sinisi A, Delrio G, Colacurci N. Endometrial LGR7 expression during menstrual cycle. Fertil Steril 2011; 95:2511-4. [DOI: 10.1016/j.fertnstert.2011.01.124] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Revised: 01/07/2011] [Accepted: 01/15/2011] [Indexed: 11/28/2022]
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98
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Haugaard-Kedström LM, Shabanpoor F, Hossain MA, Clark RJ, Ryan PJ, Craik DJ, Gundlach AL, Wade JD, Bathgate RAD, Rosengren KJ. Design, Synthesis, and Characterization of a Single-Chain Peptide Antagonist for the Relaxin-3 Receptor RXFP3. J Am Chem Soc 2011; 133:4965-74. [DOI: 10.1021/ja110567j] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Richard J. Clark
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | | | - David J. Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | | | | | | | - K. Johan Rosengren
- School of Natural Sciences, Linnaeus University, SE-391 82 Kalmar, Sweden
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
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99
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Luo X, Liu YL, Layfield S, Shao XX, Bathgate RAD, Wade JD, Guo ZY. A simple approach for the preparation of mature human relaxin-3. Peptides 2010; 31:2083-8. [PMID: 20688116 DOI: 10.1016/j.peptides.2010.07.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 07/14/2010] [Accepted: 07/14/2010] [Indexed: 11/21/2022]
Abstract
Relaxin-3 (also known as INSL7) is the most recently identified member of the insulin-like family. It is predominantly expressed in the nucleus incertus of the brain and involved in the control of stress response, food intake, and reproduction. In the present work, we have established a simple approach for the preparation of the mature human relaxin-3 peptide. We first designed and recombinantly expressed a single-chain relaxin-3 precursor in E. coli cells. After purification by immobilized metal ion affinity chromatography, refolding in vitro through disulfide reshuffling, and digestion by endoproteinase Asp-N, mature human relaxin-3 was obtained in high yield and at low cost. Peptide mapping and circular dichroism spectroscopy studies suggested that the recombinant relaxin-3 adopted an insulin-like fold with the expected disulfide linkages. The recombinant mature relaxin-3 was fully active in both RXFP3 binding and activation assays. The activity of the single-chain precursor was very low, suggesting that a free C-terminus of the B-chain is necessary for receptor-binding and activation of relaxin-3. Our present work provides a highly efficient approach for the preparation of relaxin-3 as well as its analogues for functional and structural analyses.
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Affiliation(s)
- Xiao Luo
- Institute of Protein Research, Tongji University, 1239 Siping Road, Shanghai 200092, China
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100
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Mu X, Urso ML, Murray K, Fu F, Li Y. Relaxin regulates MMP expression and promotes satellite cell mobilization during muscle healing in both young and aged mice. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 177:2399-410. [PMID: 20934971 DOI: 10.2353/ajpath.2010.091121] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The polypeptide hormone relaxin has been proven to be effective in promoting both the remodeling and regeneration of various tissues, including cardiac muscle. In addition, our previous study demonstrated that relaxin is beneficial to skeletal muscle healing by both promoting muscle regeneration and preventing fibrosis formation. However, the molecular and cellular mechanisms of relaxin in regulating both myogenic cell differentiation and muscle healing process are still unclear. In this study, C2C12 mouse myoblasts and primary human myoblasts were treated with relaxin to investigate its potential effect in vitro; relaxin was also injected intramuscularly into the injured site of the mouse on the second day after injury to observe its function in vivo, especially in the aged muscle. Results showed that relaxin promoted myogenic differentiation, migration, and activation of matrix metalloproteinases (MMPs) of cultured myoblasts in vitro. In the injured muscle, relaxin administration promoted the activation of Pax7-positive skeletal muscle satellite cells and increased its local population compared with nontreated control muscles. Meanwhile, both angiogenesis and revascularization were increased, while the extended inflammatory reaction was repressed in the relaxin-treated injured muscle. Moreover, relaxin similarly promoted muscle healing in mice with aged muscle. These results revealed the multiple effects of relaxin in systematically improving muscle healing as well as its potential for clinical applications in patients with skeletal muscle injuries and diseases.
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Affiliation(s)
- Xiaodong Mu
- Laboratory of Molecular Pathology Stem Cell Research Center (SCRC), Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Office 217, Bridgeside Point II, 450 Technology Drive Pittsburgh, PA 15219, USA
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