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Venkatesh K, Mishra C, Pradhan SK. Integrative molecular characterization and in silico analyses of caprine MC3R, MC4R, and MC5R genes. Small Rumin Res 2022. [DOI: 10.1016/j.smallrumres.2022.106812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Yeo GSH, Chao DHM, Siegert AM, Koerperich ZM, Ericson MD, Simonds SE, Larson CM, Luquet S, Clarke I, Sharma S, Clément K, Cowley MA, Haskell-Luevano C, Van Der Ploeg L, Adan RAH. The melanocortin pathway and energy homeostasis: From discovery to obesity therapy. Mol Metab 2021; 48:101206. [PMID: 33684608 PMCID: PMC8050006 DOI: 10.1016/j.molmet.2021.101206] [Citation(s) in RCA: 98] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 02/28/2021] [Accepted: 03/03/2021] [Indexed: 02/08/2023] Open
Abstract
Background Over the past 20 years, insights from human and mouse genetics have illuminated the central role of the brain leptin-melanocortin pathway in controlling mammalian food intake, with genetic disruption resulting in extreme obesity, and more subtle polymorphic variations influencing the population distribution of body weight. At the end of 2020, the U.S. Food and Drug Administration (FDA) approved setmelanotide, a melanocortin 4 receptor agonist, for use in individuals with severe obesity due to either pro-opiomelanocortin (POMC), proprotein convertase subtilisin/kexin type 1 (PCSK1), or leptin receptor (LEPR) deficiency. Scope of review Herein, we chart the melanocortin pathway's history, explore its pharmacology, genetics, and physiology, and describe how a neuropeptidergic circuit became an important druggable obesity target. Major conclusions Unravelling the genetics of the subset of severe obesity has revealed the importance of the melanocortin pathway in appetitive control; coupling this with studying the molecular pharmacology of compounds that bind melanocortin receptors has brought a new obesity drug to the market. This process provides a drug discovery template for complex disorders, which for setmelanotide took 25 years to transform from a single gene into an approved drug.
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Affiliation(s)
- Giles S H Yeo
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
| | | | - Anna-Maria Siegert
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
| | - Zoe M Koerperich
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA 55455.
| | - Mark D Ericson
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA 55455.
| | - Stephanie E Simonds
- Metabolism, Diabetes, and Obesity Programme, Monash Biomedicine Discovery Institute, and Department of Physiology, Monash University, Clayton, Victoria, Australia.
| | - Courtney M Larson
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA 55455.
| | - Serge Luquet
- Université de Paris, BFA, UMR 8251, CNRS, Paris, France.
| | - Iain Clarke
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC 3010, Australia.
| | | | - Karine Clément
- Assistance Publique Hôpitaux de Paris, Nutrition Department, Pitié-Salpêtrière Hospital, Paris, France, Sorbonne Université, INSERM, Nutrition and Obesity: Systemic Approaches (NutriOmics) Research Unit, Paris, France.
| | - Michael A Cowley
- Metabolism, Diabetes, and Obesity Programme, Monash Biomedicine Discovery Institute, and Department of Physiology, Monash University, Clayton, Victoria, Australia.
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA 55455.
| | | | - Roger A H Adan
- Department of Translational Neuroscience, UMCU Brain Centre, University Medical Centre Utrecht, Utrecht University, the Netherlands; Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Sweden.
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Li L, Xu Y, Zheng J, Kuang Z, Zhang C, Li N, Lin G, Zhang C. Pharmacological modulation of dual melanocortin-4 receptor signaling by melanocortin receptor accessory proteins in the Xenopus laevis. J Cell Physiol 2021; 236:5980-5993. [PMID: 33501674 DOI: 10.1002/jcp.30280] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/29/2020] [Accepted: 01/04/2021] [Indexed: 01/09/2023]
Abstract
Physiological modulation of melanocortin-4 receptor (MC4R) signaling by MRAP2 proteins plays an indispensable role in appetite control and energy homeostasis in the central nervous system. Great interspecies differences of the interaction and regulation of melanocortin receptors by MRAP protein family have been reported in several diploid vertebrates but never been investigated in the tetrapod amphibian Xenopus laevis. Here, we performed phylogenetic and synteny-based analyses to explore the evolutionary aspects of dual copies of X. laevis MC4R (xlMC4R) and MRAP2 (xlMRAP2) proteins. Our data showed that xlMRAPs directly interacted with xlMC4Rs on the cell surface as a functional antiparallel dimeric topology and pharmacological studies suggested a homology specific regulatory pattern of the melanocortin system in X. laevis.
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Affiliation(s)
- Lei Li
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Ying Xu
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jihong Zheng
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Zhe Kuang
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Cong Zhang
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Na Li
- Yantai Derui Bio-Tech Co., Ltd., Yantai, Shandong, China
| | - Gufa Lin
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Chao Zhang
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
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Yang Y, Chen M, Ventro G, Harmon CM. Key amino acid residue in Melanocortin-1 receptor (melanocyte α-MSH receptor) for ligand selectivity. Mol Cell Endocrinol 2017; 454:69-76. [PMID: 28579117 DOI: 10.1016/j.mce.2017.05.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 05/30/2017] [Accepted: 05/30/2017] [Indexed: 11/21/2022]
Abstract
The melanocortin-1 receptor (MC1R) is a subtype of the melanocortin receptor family and NDP-α-MSH is a non-selective agonist for MC1R. The core sequence of NDP-α-MSH, His-Phe-Arg-Trp, is important for ligand binding and biological activities at the melanocortin receptor subtypes (MCRs). A recent study indicates that Trp9 in NDP-α-MSH plays an important role in ligand selectivity. Deletion of Trp9 in NDP-α-MSH (des-Trp9-NDP-α-MSH) resulted in loss of agonist activity at MC4R, although remains agonist activity at MC1R. The molecular basis for this receptor ligand selectivity is unknown. In this study we examined what region of the MC1R is responsible for des-NDP-α-MSH selectivity. Our results indicate that (1) substitution of TM3 of MC4R with the corresponding region of MC1R switches des-Trp9-NDP-α-MSH from no activity to agonist; (2) des-Trp9-NDP-α-MSH exhibits agonistic activity at the L133M mutation of the MC4R; and (3) substitution of non-conserved amino acid residue M128 in TM3 of MC1R significantly reduced des-Trp9-NDP-α-MSH agonist activity. Our results demonstrate that amino acid residue 128 in TM3 of MC1R, or amino acid residue L133 in TM3 of the MC4R, play crucial roles in ligand des-Trp9-NDP-α-MSH selectivity at MC1R or MC4R.
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Affiliation(s)
- Yingkui Yang
- Department of Surgery, State University of New York at Buffalo, Buffalo, NY 14203, United States.
| | - Min Chen
- Department of Surgery, State University of New York at Buffalo, Buffalo, NY 14203, United States
| | - George Ventro
- Department of Surgery, State University of New York at Buffalo, Buffalo, NY 14203, United States
| | - Carroll M Harmon
- Department of Surgery, State University of New York at Buffalo, Buffalo, NY 14203, United States
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Ericson MD, Lensing CJ, Fleming KA, Schlasner KN, Doering SR, Haskell-Luevano C. Bench-top to clinical therapies: A review of melanocortin ligands from 1954 to 2016. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2414-2435. [PMID: 28363699 PMCID: PMC5600687 DOI: 10.1016/j.bbadis.2017.03.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/21/2017] [Accepted: 03/27/2017] [Indexed: 10/19/2022]
Abstract
The discovery of the endogenous melanocortin agonists in the 1950s have resulted in sixty years of melanocortin ligand research. Early efforts involved truncations or select modifications of the naturally occurring agonists leading to the development of many potent and selective ligands. With the identification and cloning of the five known melanocortin receptors, many ligands were improved upon through bench-top in vitro assays. Optimization of select properties resulted in ligands adopted as clinical candidates. A summary of every melanocortin ligand is outside the scope of this review. Instead, this review will focus on the following topics: classic melanocortin ligands, selective ligands, small molecule (non-peptide) ligands, ligands with sex-specific effects, bivalent and multivalent ligands, and ligands advanced to clinical trials. Each topic area will be summarized with current references to update the melanocortin field on recent progress. This article is part of a Special Issue entitled: Melanocortin Receptors - edited by Ya-Xiong Tao.
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Affiliation(s)
- Mark D Ericson
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Cody J Lensing
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Katlyn A Fleming
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Katherine N Schlasner
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Skye R Doering
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
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Yang Y, Harmon CM. Molecular signatures of human melanocortin receptors for ligand binding and signaling. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2436-2447. [PMID: 28478228 DOI: 10.1016/j.bbadis.2017.04.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 04/10/2017] [Accepted: 04/29/2017] [Indexed: 12/29/2022]
Abstract
Human melanocortin receptors (hMCRs) belong to the seven-transmembrane (TM) domain proteins. There are five hMCR subtypes and each of these receptor subtypes has different patterns of tissue expression and physiological function. The endogenous agonists for hMCRs are α-, β-, and γ-MSH and ACTH and endogenous antagonists are Agouti and AGRP which are the only known naturally occurring antagonists for the receptors. These peptides have their own profiles regarding the relative potency for specific hMCR subtype. Extensive studies have been performed to examine the molecular basis of the hMCRs for different ligand binding affinity and potency. Studies indicate that natural ligand α-MSH utilizes conserved amino acid residues for MCR specific binding (orthosteric binding) while synthetic ligands utilize non-conserved amino acid residues for receptor subtype specific binding (allosteric binding). ACTH is the only endogenous agonist for hMC2R and more amino acid residues at hMC2R are required for ACTH binding and signaling. HMCR computer modeling provides the detailed information of ligand and MCR interaction. This review provides the latest understanding of the molecular basis of the hMCRs for ligand binding and signaling. This article is part of a Special Issue entitled: Melanocortin Receptors - edited by Ya-Xiong Tao.
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Affiliation(s)
- Yingkui Yang
- Department of Surgery, State University of New York at Buffalo, Buffalo, NY 14203, United States.
| | - Carroll M Harmon
- Department of Surgery, State University of New York at Buffalo, Buffalo, NY 14203, United States
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Todorovic A, Ericson MD, Palusak RD, Sorensen NB, Wood MS, Xiang Z, Haskell-Luevano C. Comparative Functional Alanine Positional Scanning of the α-Melanocyte Stimulating Hormone and NDP-Melanocyte Stimulating Hormone Demonstrates Differential Structure-Activity Relationships at the Mouse Melanocortin Receptors. ACS Chem Neurosci 2016; 7:984-94. [PMID: 27135265 PMCID: PMC5596636 DOI: 10.1021/acschemneuro.6b00098] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The melanocortin system has been implicated in the regulation of various physiological functions including melanogenesis, steroidogenesis, energy homeostasis, and feeding behavior. Five melanocortin receptors have been identified to date and belong to the family of G protein-coupled receptors (GPCR). Post-translational modification of the proopiomelanocortin (POMC) prohormone leads to the biosynthesis of the endogenous melanocortin agonists, including α-melanocyte stimulating hormone (α-MSH), β-MSH, γ-MSH, and adrenocorticotropic hormone (ACTH). All the melanocortin agonists derived from the POMC prohormone contain a His-Phe-Arg-Trp tetrapeptide sequence that has been implicated in eliciting the pharmacological responses at the melanocortin receptors. Herein, an alanine (Ala) positional scan is reported for the endogenous α-MSH ligand and the synthetic, more potent, NDP-MSH peptide (Ac-Ser(1)-Tyr(2)-Ser(3)-Nle(4)-Glu(5)-His(6)-DPhe(7)-Arg(8)-Trp(9)-Gly(10)-Lys(11)-Pro(12)-Val(13)-NH2) at the cloned mouse melanocortin receptors to test the assumption that the structure-activity relationships of one ligand would apply to the other. Several residues outside of the postulated pharmacophore altered potency at the melanocortin receptors, most notably the 1560-, 37-, and 15-fold potency loss when the Glu(5) position of α-MSH was substituted with Ala at the mMC1R, mMC3R, and mMC4R, respectively. Importantly, the altered potencies due to Ala substitutions in α-MSH did not necessarily correlate with equivalent Ala substitutions in NDP-MSH, indicating that structural modifications and corresponding biological activities in one of these melanocortin ligands may not be predictive for the other agonist.
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Affiliation(s)
- Aleksandar Todorovic
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610
| | - Mark D. Ericson
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455
| | - Ryan D. Palusak
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610
| | - Nicholas B. Sorensen
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610
| | - Michael S. Wood
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610
| | - Zhimin Xiang
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455
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Structure-Activity Relationships (SAR) of Melanocortin and Agouti-Related (AGRP) Peptides. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 681:1-18. [DOI: 10.1007/978-1-4419-6354-3_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
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Yang Y, Hruby VJ, Chen M, Crasto C, Cai M, Harmon CM. Novel binding motif of ACTH analogues at the melanocortin receptors. Biochemistry 2009; 48:9775-84. [PMID: 19743876 DOI: 10.1021/bi900634e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The melanocortin receptor (MCR) subtype family is a member of the GPCR superfamily, and each of them has a different pharmacological profile with regard to the relative potency of the endogenous and synthetic melanocortin peptides. Alpha-MSH and ACTH are endogenous nonselective agonists for MC1R, MC3R, MC4R, and MC5R. In this study, we examined the role of Phe(7) in ACTH on human (h) MC1R, MC3R, and MC4R binding and signaling. Our results indicate that substitution of Phe(7) with d-Nal(2')(7) in ACTH1-24 yields a pharmacological profile different from that for substitution of Phe(7) with d-Nal(2')(7) in MSH in hMC1R, hMC3R, and hMC4R. N-d-Nal(2')(7)-ACTH1-24 is an agonist at hMC3R and hMC4R which did not change the peptide from an agonist to an antagonist at hMC3R and hMC4R. Further experiments indicate that N-d-Nal(2')(7)-ACTH1-17 is the minimal peptide required for hMC3R and hMC4R activation. Single-amino acid substitution studies of d-Nal(2')(7)-ACTH1-17 indicate that amino acid residues 15-17 in N-d-Nal(2')(7)-ACTH1-17 are crucial for hMC3R and hMC4R activation. Substitutions of these amino acid residues reduced or abolished agonist activity at hMC3R and hMC4R. Conformational studies revealed a new beta-turn (Arg(8)-Trp(9)-Gly(10)-Lys(11)) in N-d-Nal(2')(7)-ACTH1-17, compared to the beta-turn-like structure at NDP-alpha-MSH (His(6)-d-Phe(7)-Arg(8)-Trp(9)). Our results suggest that NDP-alpha-MSH and N-d-Nal(2')(7)-ACTH1-17 do not share the same binding site; the highly basic C-terminal fragment (Lys(15)-Lys(16)-Arg(17)) of N-d-Nal(2')(7)-ACTH1-17 induced a new beta-turn, and this shift contributed the selective agonist activity at hMC3R and hMC4R.
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Affiliation(s)
- Yingkui Yang
- Department of Surgery, University of Alabama, Birmingham, Alabama 35233, USA.
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Ruwe AR, Koikov L, Abdel-Malek Z, Haskell-Luevano C, Dirain ML, Portillo F, Xiang Z, Wortman M, Knittel JJ. Semi-rigid tripeptide agonists of melanocortin receptors. Bioorg Med Chem Lett 2009; 19:5176-81. [PMID: 19635667 PMCID: PMC2758050 DOI: 10.1016/j.bmcl.2009.07.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 06/23/2009] [Accepted: 07/02/2009] [Indexed: 11/29/2022]
Abstract
A series of 30 RCO-HfR-NH(2) derivatives show preference for the mouse MC1R vs MC3-5Rs. trans-4-HOC(6)H(4)CH=CHCO-HfR-NH(2) (13) [EC(50) (nM): MC1R 83, MC3R 20500, MC4R 18130 and MC5R 935; ratio 1:246:217:11] is 11 times more potent than the lead compound LK-394 Ph(CH(2))(3)CO-HfR-NH(2) (2) and only 11 times less potent than the native tridecapeptide alpha-MSH at mMC1R. Differences in conformations of 2 and 13 are discussed.
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Affiliation(s)
- Andrew R. Ruwe
- University of Cincinnati: James L. Winkle College of Pharmacy
| | - Leonid Koikov
- College of Medicine, Department of Dermatology, Cincinnati, OH 45267, USA
| | - Zalfa Abdel-Malek
- College of Medicine, Department of Dermatology, Cincinnati, OH 45267, USA
| | | | - Marvin L. Dirain
- University of Florida, College of Pharmacy, Gainesville FL 32610, USA
| | - Federico Portillo
- University of Florida, College of Pharmacy, Gainesville FL 32610, USA
| | - Zhimin Xiang
- University of Florida, College of Pharmacy, Gainesville FL 32610, USA
| | - Matt Wortman
- Genome Research Institute, Cincinnati, OH 45267, USA
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Bednarek MA, MacNeil T, Tang R, Fong TM, Cabello MA, Maroto M, Teran A. Cyclic analogs of alpha-melanocyte-stimulating hormone (alphaMSH) with high agonist potency and selectivity at human melanocortin receptor 1b. Peptides 2008; 29:1010-7. [PMID: 18378043 DOI: 10.1016/j.peptides.2008.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Revised: 02/05/2008] [Accepted: 02/13/2008] [Indexed: 10/22/2022]
Abstract
Alpha-melanotropin (alphaMSH), Ac-Ser1-Tyr2-Ser3-Met4-Glu5-His6-Phe7-Arg8-Trp9-Gly10-Lys11-Pro12-Val13-NH2,(1) has been long recognized as an important physiological regulator of skin and hair pigmentation in mammals. Binding of this peptide to the melanocortin receptor 1 (MC1R) leads to activation of tyrosinase, the key enzyme of the melanin biosynthesis pathway. In this study, interactions of the human MC1bR (an isoform of the receptor 1a) with the synthetic cyclic analogs of alphaMSH were studied. These ligands were analogs of MTII, Ac-Nle4-cyclo-(Asp5-His6-D-Phe7-Arg8-Trp9-Lys10)-NH2, a potent pan-agonist at the human melanocortin receptors (hMC1,3-5R). In the structure of MTII, the His6-D-Phe7-Arg8-Trp9 segment has been recognized as "essential" for molecular recognition at the human melanocortin receptors (hMC1,3-5R). Herein, the role of the Trp9 in the ligand interactions with the hMC1b,3-5R has been reevaluated. Analogs with various amino acids in place of Trp9 were synthesized and tested in vitro in receptor affinity binding and cAMP functional assays at human melanocortin receptors 1b, 3, 4 and 5 (hMC1b,3-5R). Several of the new peptides were high potency agonists (partial) at hMC1bR (EC50 from 0.5 to 20 nM) and largely inactive at hMC3-5R. The bulky aromatic side chain in position 9, such as that in Trp, was found not to be essential to agonism (partial) of the studied peptides at hMC1bR.
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MESH Headings
- Binding, Competitive
- Cyclic AMP/analysis
- Cyclic AMP/biosynthesis
- Humans
- Inhibitory Concentration 50
- Molecular Structure
- Peptides, Cyclic/chemical synthesis
- Peptides, Cyclic/chemistry
- Peptides, Cyclic/isolation & purification
- Peptides, Cyclic/metabolism
- Peptides, Cyclic/pharmacology
- Receptor, Melanocortin, Type 1/agonists
- Receptor, Melanocortin, Type 1/chemistry
- Receptor, Melanocortin, Type 1/classification
- Sensitivity and Specificity
- Structure-Activity Relationship
- alpha-MSH/analogs & derivatives
- alpha-MSH/chemical synthesis
- alpha-MSH/chemistry
- alpha-MSH/isolation & purification
- alpha-MSH/metabolism
- alpha-MSH/pharmacology
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Affiliation(s)
- Maria A Bednarek
- Department of Medicinal Chemistry, Merck Research Laboratories, R50G-140, P.O. Box 2000, Rahway, NJ, USA.
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