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Yang Y, Harmon CM. Molecular determinants of ACTH receptor for ligand selectivity. Mol Cell Endocrinol 2020; 503:110688. [PMID: 31866318 DOI: 10.1016/j.mce.2019.110688] [Citation(s) in RCA: 4] [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: 07/30/2019] [Revised: 12/03/2019] [Accepted: 12/16/2019] [Indexed: 01/04/2023]
Abstract
The adrenocorticotropic hormone (ACTH) receptor, known as the melanocortin-2 receptor (MC2R), plays a key role in regulating adrenocortical function. ACTH receptor is a subtype of the melanocortin receptor family which is a member of the G-protein coupled receptor (GPCR) superfamily. ACTH receptor has unique characteristics among MCRs. α-MSH, β-MSH, γ-MSH and ACTH are agonists for MCRs but only ACTH is the agonist for ACTH receptor. In addition, the melanocortin receptor accessory protein (MRAP) is required for ACTH receptor expression at cell surface and function. In this review, we summarized the information available on the relationship between ACTH and ACTH receptor and provide the latest understanding of the molecular basis of the ACTH receptor responsible for ligand selectivity and function.
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Affiliation(s)
- Yingkui Yang
- Department of Surgery, State University of New York at Buffalo, USA.
| | - Carroll M Harmon
- Department of Surgery, State University of New York at Buffalo, USA
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Harno E, Gali Ramamoorthy T, Coll AP, White A. POMC: The Physiological Power of Hormone Processing. Physiol Rev 2019; 98:2381-2430. [PMID: 30156493 DOI: 10.1152/physrev.00024.2017] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pro-opiomelanocortin (POMC) is the archetypal polypeptide precursor of hormones and neuropeptides. In this review, we examine the variability in the individual peptides produced in different tissues and the impact of the simultaneous presence of their precursors or fragments. We also discuss the problems inherent in accurately measuring which of the precursors and their derived peptides are present in biological samples. We address how not being able to measure all the combinations of precursors and fragments quantitatively has affected our understanding of the pathophysiology associated with POMC processing. To understand how different ratios of peptides arise, we describe the role of the pro-hormone convertases (PCs) and their tissue specificities and consider the cellular processing pathways which enable regulated secretion of different peptides that play crucial roles in integrating a range of vital physiological functions. In the pituitary, correct processing of POMC peptides is essential to maintain the hypothalamic-pituitary-adrenal axis, and this processing can be disrupted in POMC-expressing tumors. In hypothalamic neurons expressing POMC, abnormalities in processing critically impact on the regulation of appetite, energy homeostasis, and body composition. More work is needed to understand whether expression of the POMC gene in a tissue equates to release of bioactive peptides. We suggest that this comprehensive view of POMC processing, with a focus on gaining a better understanding of the combination of peptides produced and their relative bioactivity, is a necessity for all involved in studying this fascinating physiological regulatory phenomenon.
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Affiliation(s)
- Erika Harno
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| | - Thanuja Gali Ramamoorthy
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| | - Anthony P Coll
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
| | - Anne White
- Division of Diabetes, Endocrinology and Gastrointestinal Sciences, Faculty of Biology, Medicine and Health, University of Manchester , Manchester , United Kingdom ; and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science , Cambridge , United Kingdom
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Yang Y, Mishra V, Crasto CJ, Chen M, Dimmitt R, Harmon CM. Third transmembrane domain of the adrenocorticotropic receptor is critical for ligand selectivity and potency. J Biol Chem 2015; 290:7685-92. [PMID: 25605722 DOI: 10.1074/jbc.m114.596122] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ACTH receptor, known as the melanocortin-2 receptor (MC2R), plays an important role in regulating and maintaining adrenocortical function. MC2R is a subtype of the melanocortin receptor (MCR) family and has unique characteristics among MCRs. Endogenous ACTH is the only endogenous agonist for MC2R, whereas the melanocortin peptides α-, β-, and γ-melanocyte-stimulating hormone and ACTH are full agonists for all other MCRs. In this study, we examined the molecular basis of MC2R responsible for ligand selectivity using ACTH analogs and MC2R mutagenesis. Our results indicate that substitution of Phe(7) with D-Phe or D-naphthylalanine (D-Nal(2')) in ACTH(1-24) caused a significant decrease in ligand binding affinity and potency. Substitution of Phe(7) with D-Nal(2') in ACTH(1-24) did not switch the ligand from agonist to antagonist at MC2R, which was observed in MC3R and MC4R. Substitution of Phe(7) with D-Phe(7) in ACTH(1-17) resulted in the loss of ligand binding and activity. Molecular analysis of MC2R indicated that only mutation of the third transmembrane domain of MC2R resulted in a decrease in D-Phe ACTH binding affinity and potency. Our results suggest that Phe(7) in ACTH plays an important role in ligand selectivity and that the third transmembrane domain of MC2R is crucial for ACTH selectivity and potency.
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Affiliation(s)
- Yingkui Yang
- From the Department of Surgery, State University of New York at Buffalo, Buffalo, New York 14203 and
| | | | | | - Min Chen
- From the Department of Surgery, State University of New York at Buffalo, Buffalo, New York 14203 and
| | - Reed Dimmitt
- Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama 35233
| | - Carroll M Harmon
- From the Department of Surgery, State University of New York at Buffalo, Buffalo, New York 14203 and
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Bijl WAAJ, van Nispen JW, Greven HM. Synthesis and melanotropic activity of γ-melanotropin. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19811000311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Interactions of the melanocortin-4 receptor with the peptide agonist NDP-MSH. J Mol Biol 2010; 401:433-50. [PMID: 20600126 PMCID: PMC3101337 DOI: 10.1016/j.jmb.2010.06.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 06/14/2010] [Accepted: 06/15/2010] [Indexed: 02/05/2023]
Abstract
Melanocortin-4 receptor (MC4R) has an important regulatory role in energy homeostasis and food intake. Peptide agonists of the MC4R are characterized by the conserved sequence His6-Phe7-Arg8-Trp9, which is crucial for their interaction with the receptor. This investigation utilized the covalent attachment approach to identify receptor residues in close proximity to the bound ligand [Nle4,d-Phe7]melanocyte-stimulating hormone (NDP-MSH), thereby differentiating between residues directly involved in ligand binding and those mutations that compromise ligand binding by inducing conformational changes in the receptor. Also, recent X-ray structures of G-protein-coupled receptors were utilized to refine a model of human MC4R in the active state (R⁎), which was used to generate a better understanding of the binding mode of the ligand NDP-MSH at the atomic level. The mutation of residues in the human MC4R—such as Leu106 of extracellular loop 1, and Asp122, Ile125, and Asp126 of transmembrane (TM) helix 3, His264 (TM6), and Met292 (TM7)—to Cys residues produced definitive indications of proximity to the side chains of residues in the core region of the peptide ligand. Of particular interest was the contact between d-Phe7 on the ligand and Ile125 of TM3 on the MC4R. Additionally, Met292 (TM7) equivalent to Lys(7.45) (Ballesteros numbering scheme) involved in covalently attaching retinal in rhodopsin is shown to be in close proximity to Trp9. For the first time, the interactions between the terminal regions of NDP-MSH and the receptor are described. The amino-terminus appears to be adjacent to a series of hydrophilic residues with novel interactions at Cys196 (TM5) and Asp189 (extracellular loop 2). These interactions are reminiscent of sequential ligand binding exhibited by the β2-adrenergic receptor, with the former interaction being equivalent to the known interaction involving Ser204 of the β2-adrenergic receptor.
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BRINKMAN R, VENINGA TS. Contributions to the Study of Immediate and Early X-ray Reactions with Regard to Chemoprotection. ACTA ACUST UNITED AC 2009; 4:249-54. [PMID: 13873128 DOI: 10.1080/09553006214550041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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YANG YOUNGC, HRUBY VICTORJ, HEWARD CHRISTOPHERB, HADLEY MACE. SYNTHESIS OF α- AND β-MELANOCYTE STIMULATING HORMONES*. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1399-3011.1980.tb02559.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Blake J, Li CH. Adrenocorticotropin. 48. Synthesis and biological activity of (15, 16-D-lysine, 17, 18-D-arginine)-adrenocorticotropin-(1-19) and an all-D-retropeptide related to the amino terminal octadecapeptide of adrenocorticotropin. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 2009; 8:589-95. [PMID: 186422 DOI: 10.1111/j.1399-3011.1976.tb02539.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The peptide [15, 16-D-lysine, 17, 18-D-arginine]-adrenocorticotropin-(1-19) and an all-D-retropeptide related to the amino terminal octadecapeptide of adrenocorticotropin have been synthesized by the solid-phase method. The nonadecapeptide was shown to possess 10-15% of the steroidogenic activity and 3% of the lipolytic activity of adrenocorticotropin-(1-19). The all-D-retropeptide showed no activity and exhibited no inhibitory activity in steroidogenesis and lipolysis.
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Wang KT, Blake J, Li CH. The solid-phase synthesis of human and monkey beta-melanotropins. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 2009; 5:33-6. [PMID: 4357823 DOI: 10.1111/j.1399-3011.1973.tb02316.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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WILKES BRIANC, CODY WAYNEL, HRUBY VICTORJ, CASTRUCCI ANAMARIEDEL, HADLEY MACE. Comparative biological activities of potent analogues of α-melanotropin. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1399-3011.1986.tb01066.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Hadley ME, Heward CB, Hruby VJ, Sawyer TK, Yang YC. Biological actions of melanocyte-stimulating hormone. CIBA FOUNDATION SYMPOSIUM 2008; 81:244-62. [PMID: 6268380 DOI: 10.1002/9780470720646.ch14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Melanocyte-stimulating hormone (alpha-melanotropin, MSH) may function in a number of diverse physiological roles. MSH stimulates (1) rapid translocation of melanosomes (melanin granules) in dermal melanophores to effect rapid colour change and (2) melanogenesis in normal and abnormal (melanoma) epidermal melanocytes. Both actions involve (1) initial binding of the peptide on the melanocyte membrane, (2) transduction of signal to adenylate cyclase, and (3) increased cytosolic levels of cyclic AMP. Efforts to prepare radioiodinated MSH and analogues for radioreceptor studies using melanoma membranes and intact cells reveal that conventional iodination procedures inactivate the hormone because of oxidative and iodination effects on specific structural components of the peptide. These effects can be circumvented by the use of synthetically tailored MSH analogues. Transduction of signal from receptor to adenylate cyclase requires calcium, but prostaglandin or beta-adrenoceptor stimulation of melanophores does not. The nucleotide and metal ion requirements for mouse melanoma adenylate cyclase activity have been characterized. There is both a transcriptional and translational requirement for MSH stimulation of tyrosinase activity and melanin production in melanoma cells. Melanosome translocation within melanophores is enhanced in the absence of extracellular calcium. A model for the MSH control of melanosome movements suggests a bifunctional, but compartmentalized, role for calcium in the action of MSH.
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Chen M, Aprahamian CJ, Kesterson RA, Harmon CM, Yang Y. Molecular identification of the human melanocortin-2 receptor responsible for ligand binding and signaling. Biochemistry 2007; 46:11389-97. [PMID: 17877367 PMCID: PMC3216636 DOI: 10.1021/bi700125e] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The melanocortin-2 receptor (MC2R), also known as the adrenocorticotropic hormone (ACTH) receptor, plays an important role in regulating and maintaining adrenocortical function, specifically steroidogenesis. Mutations of the human MC2R (hMC2R) gene have also been identified in humans with familial glucocorticoid deficiency; however, the molecular basis responsible for hMC2R ligand binding and signaling remains unclear. In this study, both truncated ACTH peptides and site-directed mutagenesis studies were used to determine molecular mechanisms of hMC2R binding ACTH and signaling. Our results indicate that ACTH1-16 is the minimal peptide required for hMC2R binding and signaling. Mutations of common melanocortin receptor family amino acid residues E80 in transmembrane domain 2 (TM2), D107 in TM3, F178 in TM4, F235 and H238 in TM6, and F258 in TM7 significantly reduced ACTH-binding affinity and signaling. Furthermore, mutations of unique amino acids D104 and F108 in TM3 and F168 and F178 in TM4 significantly decreased ACTH binding and signaling. In conclusion, our results suggest that the residues in TM2, TM3, and TM6 of hMC2R share similar binding sites with other MCRs but the residues identified in TM4 and TM7 of hMC2R are unique and required for ACTH selectivity. Our study suggests that hMC2R may have a broad binding pocket in which both conserved and unique amino acid residues are required, which may be the reason why alpha-MSH was not able to bind hMC2R.
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Affiliation(s)
- Min Chen
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, 35233
| | | | | | - Carroll M. Harmon
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, 35233
| | - Yingkui Yang
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, 35233
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Ross GT, Odell WD. THE EFFECTS OF TEMPERATURE ON THE RESPONSE TO MELANOCYTE-STIMULATING HORMONE. Ann N Y Acad Sci 2006. [DOI: 10.1111/j.1749-6632.1963.tb42884.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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McGuire JS, Lerner AB. EFFECTS OF TRICOSAPEPTIDE “ACTH” AND ALPHA- MELANOCYTE-STIMULATING HORMONE ON THE SKIN COLOR OF MAN*. Ann N Y Acad Sci 2006. [DOI: 10.1111/j.1749-6632.1963.tb42919.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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19
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Ross GT, Odell WD. THE EFFECTS OF TEMPERATURE ON THE RESPONSE TO MELANOCYTE-STIMULATING HORMONE. Ann N Y Acad Sci 2006. [DOI: 10.1111/j.1749-6632.1963.tb42926.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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TEAGUE RS, PATTON JR. REFLECTANCE RESPONSES OF FROGS TO MELANOPHORE HORMONE*. Ann N Y Acad Sci 2006; 100:686-95. [PMID: 13980415 DOI: 10.1111/j.1749-6632.1963.tb42925.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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McGuire JS, Lerner AB. EFFECTS OF TRICOSAPEPTIDE “ACTH” AND ALPHA-MELANOCYTE-STIMULATING HORMONE ON THE SKIN COLOR OF MAN*. Ann N Y Acad Sci 2006. [DOI: 10.1111/j.1749-6632.1963.tb42877.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Novales RR. RESPONSES OF CULTURED MELANOPHORES TO THE SYNTHETIC HORMONES α-MSH, MELATONIN, AND EPINEPHRINE*. Ann N Y Acad Sci 2006. [DOI: 10.1111/j.1749-6632.1963.tb42907.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Novales RR. RESPONSES OF CULTURED MELANOPHORES TO THE SYNTHETIC HORMONES α-MSH, MELATONIN, AND EPINEPHRINE*. Ann N Y Acad Sci 2006. [DOI: 10.1111/j.1749-6632.1963.tb42949.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ramachandran J, Choh Hao LI. Structure-activity relationships of the adrenocorticotropins and melanotropins: the synthetic approach. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 29:391-477. [PMID: 4302240 DOI: 10.1002/9780470122747.ch8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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LERNER AB, WRIGHT MR. In Vitro
Frog Skin Assay for Agents that Darken and Lighten Melanocytes. ACTA ACUST UNITED AC 2006; 8:295-307. [PMID: 14415936 DOI: 10.1002/9780470110249.ch7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Nikolics K, Teplán I, Medzihradszky K. Labelled polypeptides. v. synthesis of α-melanotropin labelled with tritium on the tyrosine residue, via the dibromo intermediate. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580120202] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Fittkau S, Medzihradszky K, Seprödi J. Markierte Polypeptide. IV. Synthese von [1-14C]Glycin10-α-Melanotropin. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/prac.19743160420] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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31
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Eberle AN, De Graan PNE, Hübscher W. Synthesis and biological properties ofp-azidophenylalanine13-β-melanotropin, a potent photoaffinity label for MSH receptors. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19810640823] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Eberle A, Hübscher W. α-Melanotropin Labelled at its Tyrosine2Residue: Synthesis and Biological Activities of 3′-Iodotyrosine2-,3′-125Iodotyrosine2-,3′,5′-Diiodotyrosine2-, and (3′,5′-3H2)tyrosine2-α-Melanotropin, and of Related Peptides. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19790620741] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Eberle A, Hübscher W, Schwyzer R. Synthese von radioaktiv markierten Bromacetyl- und Diazoacetyl-α-melanotropin-Derivaten zum Studium von kovalenten Hormon-Makromolekül-Komplexen. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19770600843] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Holder JR, Haskell-Luevano C. Melanocortin ligands: 30 years of structure-activity relationship (SAR) studies. Med Res Rev 2004; 24:325-56. [PMID: 14994367 DOI: 10.1002/med.10064] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The challenge of peptide and peptidomimetic research is the development of methods and techniques to improve the biological properties of native peptides and to convert peptide ligands into non-peptide compounds. Improved biological properties of peptides includes enhancement of stability, potency, and receptor selectivity, for both in vivo and in vitro applications. The design of a ligand with specific activity and desired biological properties is a complex task, and, to accomplish this objective, knowledge about putative interactions between a ligand and the corresponding receptor will be valuable. This includes interactions for both the binding and signal transduction processes. Structure-activity relationship (SAR) studies involve systematic modification of a lead peptide and are designed to provide insight into potential interactions involved in the formation of the ligand-receptor complex. It is desirable to have knowledge about both favorable and unfavorable processes that may occur in putative ligand-receptor interactions that result in either receptor stimulation or inhibition. Herein, we discuss various SAR studies that have involved melanocortin peptides over three decades and the information these studies have provided to the melanocortin field.
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Affiliation(s)
- Jerry Ryan Holder
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, USA
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Han G, Haskell-Luevano C, Kendall L, Bonner G, Hadley ME, Cone RD, Hruby VJ. De novo design, synthesis, and pharmacology of alpha-melanocyte stimulating hormone analogues derived from somatostatin by a hybrid approach. J Med Chem 2004; 47:1514-26. [PMID: 14998337 DOI: 10.1021/jm030452x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A number of alpha-melanotropin (alpha-MSH) analogues have been designed de novo, synthesized, and bioassayed at different melanocortin receptors from frog skin (fMC1R) and mouse/rat (mMC1R, rMC3R, mMC4R, and mMC5R). These ligands were designed from somatostatin by a hybrid approach, which utilizes a modified cyclic structure (H-d-Phe-c[Cys---Cys]-Thr-NH(2)) related to somatostatin analogues (e.g. sandostatin) acting at somatostatin receptors, CTAP which binds specifically to micro opioid receptors, and the core pharmacophore of alpha-MSH (His-Phe-Arg-Trp). Ligands designed were H-d-Phe-c[XXX-YYY-ZZZ-Arg-Trp-AAA]-Thr-NH(2) [XXX and AAA = Cys, d-Cys, Hcy, Pen, d-Pen; YYY = His, His(1'-Me), His(3'-Me); ZZZ = Phe and side chain halogen substituted Phe, d-Phe, d-Nal(1'), and d-Nal(2')]. The compounds showed a wide range of bioactivities at the frog skin MC1R; e.g. H-d-Phe-c[Hcy-His-d-Phe-Arg-Trp-Cys]-Thr-NH(2) (6, EC(50) = 0.30 nM) and H-d-Phe-c[Cys-His-d-Phe-Arg-Trp-d-Cys]-Thr-NH(2) (8, EC(50) = 0.10 nM). In addition, when a lactam bridge was used as in H-d-Phe-c[Asp-His-d-Phe-Arg-Trp-Lys]-Thr-NH(2) (7, EC(50) = 0.10 nM), the analogue obtained is as potent as alpha-MSH in the frog skin MC1R assay. Interestingly, switching the bridge of 6 to give H-d-Phe-c[Cys-His-d-Phe-Arg-Trp-Hcy]-Thr-NH(2) (5, EC(50) = 1000 nM) led to a 3000-fold decrease in agonist activity. An increase in steric size in the side chain of d-Phe(7) reduced the bioactivity significantly. For example, H-d-Phe-c[Cys-His-d-Nal(1')-Arg-Trp-d-Cys]-Thr-NH(2) (24) is 2000-fold less active than 9. On the other hand, H-d-Phe-c[Cys-His-d-Phe(p-I)-Arg-Trp-d-Cys]-Thr-NH(2) (23) lost all agonist activity and became a weak antagonist (IC(50) = 1 x 10(-5) M). Furthermore, the modified CTAP analogues with a d-Trp at position 7 all showed weak antagonist activities (EC(50) = 10(-6) to 10(-7) M). Compounds bioassayed at mouse/rat MCRs displayed intriguing results. Most of them are potent at all four receptors tested (mMC1R, rMC3R, mMC4R, and mMC5R) with poor selectivities. However, two of the ligands, H-d-Phe-c[Cys-His-d-Phe-Arg-Trp-Pen]-Thr-NH(2) (9, EC(50) = 6.9 x 10(-9) M, 6.4 x 10(-8) M, 2.0 x 10(-8) M, and 1.4 x 10(-10) M at mMC1R, rMC3R, mMC4R, and mMC5R, respectively) and H-d-Phe-c[Cys-His(3'-Me)-d-Phe-Arg-Trp-Cys]-Thr-NH(2) (16, EC(50) = 3.5 x 10(-8) M, 3.1 x 10(-8) M, 8.8 x 10(-9) M, and 5.5 x 10(-10) M at mMC1R, rMC3R, mMC4R, and mMC5R, respectively) showed significant selectivities for the mMC5R. Worthy of mention is that neither of these two ligands is potent in the frog skin MC1R assay (EC(50) = 10(-7) M for 9 and EC(50) = 10(-5) M for 16). These results clearly demonstrated that binding behaviors in rodent MCRs are quite different from those in the classical frog skin (R pipiens) assay.
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MESH Headings
- Animals
- Cysteine/chemistry
- Drug Design
- In Vitro Techniques
- Mice
- Molecular Conformation
- Peptides, Cyclic/chemical synthesis
- Peptides, Cyclic/pharmacology
- Rana pipiens
- Rats
- Receptor, Melanocortin, Type 1/metabolism
- Receptor, Melanocortin, Type 3/metabolism
- Receptor, Melanocortin, Type 4/metabolism
- Receptors, Corticotropin/metabolism
- Receptors, Melanocortin
- Skin/metabolism
- Somatostatin/analogs & derivatives
- Somatostatin/chemical synthesis
- Somatostatin/pharmacology
- Structure-Activity Relationship
- alpha-MSH/analogs & derivatives
- alpha-MSH/chemical synthesis
- alpha-MSH/pharmacology
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Affiliation(s)
- Guoxia Han
- Departments of Chemistry and Anatomy, University of Arizona, Tucson, Arizona 85721, USA.
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36
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Frangioni G, Borgioli G, Bianchi S. Melatonin, melanogenesis, and hypoxic stress in the newt, Triturus carnifex. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, COMPARATIVE EXPERIMENTAL BIOLOGY 2003; 296:125-36. [PMID: 12658718 DOI: 10.1002/jez.a.10261] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Groups of 6 specimens each of the newt Triturus carnifex were treated with melatonin to see if the hormone inhibited melanogenesis in the Kupffer cells of the liver (melanomacrophages), a process markedly stimulated by hypoxia. A dose of 500 microg/g in 27% ethanol, injected intraperitoneally, induced loss of consciousness and tetany of all the skeletal muscles, which on the contrary appeared relaxed in animals pre-anesthetised by immersion in chlorbutol at 0.2%. Anesthetised specimens injected with melatonin showed a significantly lower increase in hepatic pigmentation after acute hypoxia, a condition attained by sealing each specimen in a 620 mL respiratory chamber with water containing 1.1 ppm of oxygen for the time needed to consume it all (about two hours). If hypoxia is reached gradually, beginning with 8 ppm of oxygen (normoxic condition), the increase in hepatic pigmentation after melatonin injection does not differ significantly from that of non-hormone treated specimens: thus melatonin does not seem to play a direct part in controlling hepatic melanogenesis. Instead, the hormone induces significant increase in oxygen consumption, marked general steatosis of the liver and the almost total disappearance of glycogen. Intraperitoneal injection of 500 microg/g of melatonin in anesthetised animals exposed to the air (normoxic) also causes severe steatosis and an unexpected increase in the hepatic deposits of melanin, as after hypoxic treatment. A dose of 100 ng/g in 1% ethanol, ineffective when injected intraperitoneally, also induces these effects if injected directly into the arterial blood-stream through the conus arteriosus, thus avoiding the hepatic filter. The phenomena observed appear to be induced by a powerful endocrine mechanism that provokes metabolic hypoxia by consuming all the available ATP for synthesizing fat. A less intense form of steatosis can also be observed in animals subjected to hypoxia but without prior hormone treatment, indicating that a natural process triggered by hypoxic stress is pushed to the extreme by exogenous melatonin: the hormone changes the entire energy metabolism of the organism so that it can survive for a long time under adverse environmental conditions.
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Affiliation(s)
- Giuliano Frangioni
- Department of Animal Biology and Genetics, University of Florence, Florence, Italy.
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Cowell SM, Balse-Srinivasan PM, Ahn JM, Hruby VJ. Design and synthesis of peptide antagonists and inverse agonists for G protein-coupled receptors. Methods Enzymol 2002; 343:49-72. [PMID: 11665587 DOI: 10.1016/s0076-6879(02)43127-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Affiliation(s)
- Scott M Cowell
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA
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38
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Slominski A, Wortsman J, Luger T, Paus R, Solomon S. Corticotropin releasing hormone and proopiomelanocortin involvement in the cutaneous response to stress. Physiol Rev 2000; 80:979-1020. [PMID: 10893429 DOI: 10.1152/physrev.2000.80.3.979] [Citation(s) in RCA: 559] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The skin is a known target organ for the proopiomelanocortin (POMC)-derived neuropeptides alpha-melanocyte stimulating hormone (alpha-MSH), beta-endorphin, and ACTH and also a source of these peptides. Skin expression levels of the POMC gene and POMC/corticotropin releasing hormone (CRH) peptides are not static but are determined by such factors as the physiological changes associated with hair cycle (highest in anagen phase), ultraviolet radiation (UVR) exposure, immune cytokine release, or the presence of cutaneous pathology. Among the cytokines, the proinflammatory interleukin-1 produces important upregulation of cutaneous levels of POMC mRNA, POMC peptides, and MSH receptors; UVR also stimulates expression of all the components of the CRH/POMC system including expression of the corresponding receptors. Molecular characterization of the cutaneous POMC gene shows mRNA forms similar to those found in the pituitary, which are expressed together with shorter variants. The receptors for POMC peptides expressed in the skin are functional and include MC1, MC5 and mu-opiate, although most predominant are those of the MC1 class recognizing MSH and ACTH. Receptors for CRH are also present in the skin. Because expression of, for example, the MC1 receptor is stimulated in a similar dose-dependent manner by UVR, cytokines, MSH peptides or melanin precursors, actions of the ligand peptides represent a stochastic (predictable) nonspecific response to environmental/endogenous stresses. The powerful effects of POMC peptides and probably CRH on the skin pigmentary, immune, and adnexal systems are consistent with stress-neutralizing activity addressed at maintaining skin integrity to restrict disruptions of internal homeostasis. Hence, cutaneous expression of the CRH/POMC system is highly organized, encoding mediators and receptors similar to the hypothalamic-pituitary-adrenal (HPA) axis. This CRH/POMC skin system appears to generate a function analogous to the HPA axis, that in the skin is expressed as a highly localized response which neutralizes noxious stimuli and attendant immune reactions.
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Affiliation(s)
- A Slominski
- Department of Pathology, Loyola University Medical Center, Maywood, Illinois, USA
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39
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HARRIS JI. Studies on pituitary polypeptide hormones. III. The structure of alpha-melanocyte-stimulating hormone from pig pituitary glands. Biochem J 2000; 71:451-9. [PMID: 13638250 PMCID: PMC1196817 DOI: 10.1042/bj0710451] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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40
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Bhardwaj R, Hadley ME, Dorr RT, Dvorakova K, Brooks C, Blanchard J. Pharmacologic response of a controlled-release PLGA formulation for the alpha-melanocyte stimulating hormone analog, Melanotan-I. Pharm Res 2000; 17:593-9. [PMID: 10888312 DOI: 10.1023/a:1007525117894] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE The objective of this study was to evaluate in vitro and in vivo the melanogenic activity of one-month duration Melanotan-I (MT-I) implants prepared using poly (D,L lactide-co-glycolide) polymer. METHODS The biological activity of the samples of MT-I released in vitro from the non-irradiated or gamma irradiated implants was measured using a frog skin bioassay. The effect of MT-I on skin pigmentation was measured using a Chroma meter (reflectometer) after subcutaneous administration of implants containing 4 mg MT-I to guinea pigs. Eumelanin, the black/brown melanin pigment, was quantified in skin biopsies as pyrrole-2, 3, 5-tricarboxylic acid using HPLC. RESULTS The MT-I released in vitro from implants after 24 hours exhibited 100% melanotropic activity in frog skins compared to an identical concentration of a freshly prepared MT-I standard. The reflectance readings demonstrated a prolonged skin darkening for up to three months as evidenced by the decrease in the luminance values from 0 to -4.82. A 2.5-fold increase in eumelanin levels was observed after one month and the increased pigmentation lasted for 3 months. CONCLUSIONS The melanogenic response to MT-I implants persisted for three months and the increase in pigmentation, especially the increased eumelanin levels, could provide protection from ultraviolet radiation.
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Affiliation(s)
- R Bhardwaj
- Genzyme Corporation, Framingham, Massachusetts 01701, USA
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Vaudry H, Chartrel N, Desrues L, Galas L, Kikuyama S, Mor A, Nicolas P, Tonon MC. The pituitary-skin connection in amphibians. Reciprocal regulation of melanotrope cells and dermal melanocytes. Ann N Y Acad Sci 1999; 885:41-56. [PMID: 10816640 DOI: 10.1111/j.1749-6632.1999.tb08664.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In amphibians, alpha-MSH secreted by the pars intermedia of the pituitary plays a pivotal role in the process of skin color adaptation. Reciprocally, the skin of amphibians contains a number of regulatory peptides, some of which have been found to regulate the activity of pituitary melanotrope cells. In particular, the skin of certain species of amphibians harbours considerable amounts of thyrotropin-releasing hormone, a highly potent stimulator of alpha-MSH release. Recently, we have isolated and sequenced from the skin of the frog Phyllomedusa bicolor--a novel peptide named skin peptide tyrosine tyrosine (SPYY), which exhibits 94% similarity with PYY from the frog Rana ridibunda. For concentrations ranging from 5 x 10(-10) to 10(-7) M, SPYY induces a dose-related inhibition of alpha-MSH secretion. At a dose of 10(-7) M, SPYY totally abolished alpha-MSH release. These data strongly suggest the existence of a regulatory loop between the pars intermedia of the pituitary and the skin in amphibians.
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Affiliation(s)
- H Vaudry
- European Institute for Peptide Research (IFRMP n(o) 23), Laboratory of Cellular and Molecular Neuroendocrinology, INSERM U 413, UA CNRS, University of Rouen, Mont-Saint-Aignan, France
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42
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Abstract
This is a semi-autobiographical coverage of my research career in pigment cell biology presented in the context of the emergence and growth of the discipline. This anecdotal presentation tells about some historical personages in the field. My undergraduate studies at the University of Rochester are related to my graduate work at the University of Iowa. I tell how my dissertation research was derived from a marriage between my interests in experimental embryology and the new field of comparative endocrinology. My early years of research at Iowa and as a young faculty member in Zoology at the University of Arizona were much concerned with the evolution of our knowledge of the chemistry and biology of melanocyte-stimulating hormone (MSH), especially concerning the pigment cells of lower vertebrates. Our developmental, structural, functional, and biochemical characterization of vertebrate chromatophores is described, as is our elucidation of the dermal chromatophore unit. The direct effects of light on changes in pigmentation are considered in descriptions of both the tail-darkening reaction and the role of the pineal gland in melanophore control. Emphasis is placed on the developmental biology of pigmentation, especially on the concept that all pigment cells are derived in common from a stem cell of neural-crest origin, whose expression is influenced by factors, such as melanization-inhibiting factor (MIF), localized in specific areas of the skin to thus produce specific pigmentation patterns. This research is considered in light of what is known about the agouti locus and MSH in the expression of mammalian pigmentation patterns. Part of my work has included ecological considerations, and some of this is touched upon. My role as founder of the journal 'Pigment Cell Research', is presented briefly, as is my involvement in the XIIIth International Pigment Cell Conference and in the establishment of both the International Pigment Cell Society and the International Federation of Pigment Cell Societies. Finally, I comment on the future of research in pigmentation.
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Affiliation(s)
- J T Bagnara
- Department of Cell Biology and Anatomy, The University of Arizona College of Medicine, Tucson 85724-5044, USA.
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Nikiforovich GV, Sharma SD, Hadley ME, Hruby VJ. Studies of conformational isomerism in alpha-melanocyte stimulating hormone by design of cyclic analogues. Biopolymers 1998; 46:155-67. [PMID: 9699465 DOI: 10.1002/(sici)1097-0282(199809)46:3<155::aid-bip3>3.0.co;2-k] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Results of energy calculations for alpha-MSH (alpha-melanocyte stimulating hormone, Ac-Ser1-Tyr2-Ser3-Met4-Glu5-His6-Phe7-Arg8-Trp9- Gly10-Lys11-Pro12-Val13-NH2) and [D-Phe7] alpha-MSH were used for design of cyclic peptides with the general aim to stabilize different conformational isomers of the parent compound. The minimal structural modifications of the conformationally flexible Gly10 residue, as substitutions for L-Ala, D-Ala, or Aib (replacing of hydrogen atoms by methyl groups), were applied to obtain octa- and heptapeptide analogues of alpha-MSH(4-11) and alpha-MSH(5-11), which were cyclized by lactam bridges between the side chains in positions 5 and 11. Some of these analogues, namely those with substitutions of the Gly10 residue with L-Ala or Aib, showed biological activity potencies on frog skin comparable to the potency of the parent tridecapeptide hormone. Additional energy calculations for designed cyclic analogues were used for further refinement of the model for the biologically active conformations of the His-Phe-Arg-Trp "message" sequence within the sequences of alpha-MSH and [D-Phe7]alpha-MSH. In such conformations the aromatic moieties of the side chains of the His6, L/D-Phe7, and Trp9 residues form a continuous hydrophobic "surface," presumably interacting with a complementary receptor site. This feature is characteristic for low-energy conformers of active cyclic analogues, but it is absent in the case of inactive analogues. This particular spatial arrangement of functional groups involved in the message sequence is very close for alpha-MSH and [D-Phe7]alpha-MSH, as well as for biologically active cyclic analogues despite differences of dihedral angle values for corresponding low-energy conformations.
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Affiliation(s)
- G V Nikiforovich
- Department of Chemistry, University of Arizona, Tucson 85721, USA
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46
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Hruby VJ, Han G, Hadley ME. Design and bioactivities of melanotropic peptide agonists and antagonists: Design based on a conformationally constrained somatostatin template. ACTA ACUST UNITED AC 1998. [DOI: 10.1007/bf02443451] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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47
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Masthay MB. Color Changes Induced by Pigment Granule Aggregation in Chromatophores: A Quantitative Model Based on Beer's Law. Photochem Photobiol 1997. [DOI: 10.1111/j.1751-1097.1997.tb03202.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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48
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Haskell-Luevano C, Toth K, Boteju L, Job C, Castrucci AM, Hadley ME, Hruby VJ. beta-Methylation of the Phe7 and Trp9 melanotropin side chain pharmacophores affects ligand-receptor interactions and prolonged biological activity. J Med Chem 1997; 40:2740-9. [PMID: 9276019 DOI: 10.1021/jm970018t] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Topographically modified melanotropin side chain pharmacophore residues Phe7 and Trp9 in a cyclic peptide template (Ac-Nle4-c[Asp-His-Xaa7-Arg-Yaa9-Lys]-NH2) and Phe7 in a linear peptide template (Ac-Ser-Tyr-Ser-Nle4-Glu-His-Xaa7-Arg-Trp-Gly-Lys-Pro-Val-NH2) result in differences in potency and prolonged biological activity in the frog and lizard skin bioassays. These topographic modifications included the four isomers of beta-methylphenylalanine (beta-MePhe)7 and beta-methyltryptophan (beta-MeTrp)9 and the two isomers of 1,2,3,4-tetrahydro-beta-carboline (Tca)9 Modifications in the cyclic template resulted in up to a 1000-fold difference in potency for the beta-MePhe7 stereoisomeric peptides; up to a 476-fold difference in potency resulted for the beta-MeTrp9 peptides, and about a 50-fold difference between the Tca9-containing peptides. Up to a 40-fold difference in potency resulted for the beta-MePhe7 stereoisomeric peptides using the linear template in these assays. The relative potency ranking for modifications in the cyclic template of beta-MePhe7 were 2R,3S > 2S,3S = 2S,3R > 2R,3R in the frog assay and 2S,3R > 2R,3S > 2S,3S > 2R,3R in the lizard assay. The relative potencies for modifications in the cyclic template of beta-MeTrp9 were 2R,3S > 2R,3R > 2S,3S > > 2S,3R in the frog assay and 2S,3S = 2R,3R > 2R,3S > 2S,3R in the lizard assay. The relative potencies for modifications in the cyclic template of Tca9 were DTca > LTca in both assays. Significant differences in prolonged (residual) activities were also observed for these modified peptides and were dependent upon stereochemistry of the beta-methyl amino acid, peptide template, and bioassay system. Furthermore, comparisons of beta-MeTrp9 stereoisomeric peptides on the frog, lizard, and human MC1 receptors suggest that structure-activity relationships on both the classical frog and lizard skin bioassays do not necessarily predict corresponding SAR profiles for the human melanocortin receptors, indicating a remarkable species specificity of the MC1 receptor requirements.
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Haskell-Luevano C, Hendrata S, North C, Sawyer TK, Hadley ME, Hruby VJ, Dickinson C, Gantz I. Discovery of prototype peptidomimetic agonists at the human melanocortin receptors MC1R and MC4R. J Med Chem 1997; 40:2133-9. [PMID: 9216831 DOI: 10.1021/jm960840h] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
[Nle4, DPhe7]-alpha-MSH (NDP-MSH), a highly potent analogue of alpha-melanocyte-stimulating hormone (alpha-MSH), possesses nanomolar efficacies at all the melanocortin receptor subtypes except the MC2R. Evaluation of the melanocortin "message" sequence of [Nle4, DPhe7]-alpha-MSH was performed on the human melanocortin receptor subtypes designated hMC1, hMC3R, hMC4R, and hMC5R. Tetrapeptides and tripeptides were stereochemically modified to explore topochemical preferences at these receptors and to identify lead peptides possessing agonist activity and subtype selectivity. Four peptides were discovered to only bind to the hMC1 and hMC4 receptor subtypes. The tetrapeptide Ac-His-DPhe-Arg-Trp-NH2 (1) possessed 0.6 microM binding affinity at the hMC1R, 1.2 microM binding affinity at the hMC4R, and agonist activity at both receptors. The tripeptides Ac-DPhe-Arg-Trp-NH2 (6) and Ac-DPhe-Arg-DTrp-NH2 (7) possessed 2.0 and 9.1 microM binding affinities, respectively, only at the hMC4R, and both compounds effected agonist activity. The tetrapeptide Ac-His-Phe-Arg-DTrp-NH2 (4) possessed 6.3 microM affinity and full agonist activity at the hMC1R, while only binding 7% at the hMC3R, 36% at the hMC4R, and 11% at the hMC5R at a maximal concentration of 10 microM. These data demonstrate that the His-Phe-Arg-Trp message sequence of the melanocortin peptides does not bind and stimulate each melanocortin receptor in a similar fashion, as previously hypothesized. Additionally, this study identified the simplest structural agonists for the hMC1R and hMC4R receptors reported to date.
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Affiliation(s)
- C Haskell-Luevano
- Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109, USA
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50
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Haskell-Luevano C, Hendrata S, North C, Sawyer TK, Hadley ME, Hruby VJ, Dickinson C, Gantz I. Discovery of Prototype Peptidomimetic Agonists at the Human Melanocortin Receptors MC1R and MC4R. J Med Chem 1997. [DOI: 10.1021/jm960840h order by 1-- -] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- Carrie Haskell-Luevano
- Departments of Internal Medicine, Pediatrics, and Surgery, University of Michigan Medical Center, Ann Arbor, Michigan 48109, Department of Chemistry, Parke-Davis Pharmaceutical Research, 2800 Plymouth Road, Ann Arbor, Michigan 48105, and Departments of Chemistry, and Cell Biology and Anatomy, University of Arizona, Tucson, Arizona 85721
| | - Siska Hendrata
- Departments of Internal Medicine, Pediatrics, and Surgery, University of Michigan Medical Center, Ann Arbor, Michigan 48109, Department of Chemistry, Parke-Davis Pharmaceutical Research, 2800 Plymouth Road, Ann Arbor, Michigan 48105, and Departments of Chemistry, and Cell Biology and Anatomy, University of Arizona, Tucson, Arizona 85721
| | - Cheryl North
- Departments of Internal Medicine, Pediatrics, and Surgery, University of Michigan Medical Center, Ann Arbor, Michigan 48109, Department of Chemistry, Parke-Davis Pharmaceutical Research, 2800 Plymouth Road, Ann Arbor, Michigan 48105, and Departments of Chemistry, and Cell Biology and Anatomy, University of Arizona, Tucson, Arizona 85721
| | - Tomi K. Sawyer
- Departments of Internal Medicine, Pediatrics, and Surgery, University of Michigan Medical Center, Ann Arbor, Michigan 48109, Department of Chemistry, Parke-Davis Pharmaceutical Research, 2800 Plymouth Road, Ann Arbor, Michigan 48105, and Departments of Chemistry, and Cell Biology and Anatomy, University of Arizona, Tucson, Arizona 85721
| | - Mac E. Hadley
- Departments of Internal Medicine, Pediatrics, and Surgery, University of Michigan Medical Center, Ann Arbor, Michigan 48109, Department of Chemistry, Parke-Davis Pharmaceutical Research, 2800 Plymouth Road, Ann Arbor, Michigan 48105, and Departments of Chemistry, and Cell Biology and Anatomy, University of Arizona, Tucson, Arizona 85721
| | - Victor J. Hruby
- Departments of Internal Medicine, Pediatrics, and Surgery, University of Michigan Medical Center, Ann Arbor, Michigan 48109, Department of Chemistry, Parke-Davis Pharmaceutical Research, 2800 Plymouth Road, Ann Arbor, Michigan 48105, and Departments of Chemistry, and Cell Biology and Anatomy, University of Arizona, Tucson, Arizona 85721
| | - Chris Dickinson
- Departments of Internal Medicine, Pediatrics, and Surgery, University of Michigan Medical Center, Ann Arbor, Michigan 48109, Department of Chemistry, Parke-Davis Pharmaceutical Research, 2800 Plymouth Road, Ann Arbor, Michigan 48105, and Departments of Chemistry, and Cell Biology and Anatomy, University of Arizona, Tucson, Arizona 85721
| | - Ira Gantz
- Departments of Internal Medicine, Pediatrics, and Surgery, University of Michigan Medical Center, Ann Arbor, Michigan 48109, Department of Chemistry, Parke-Davis Pharmaceutical Research, 2800 Plymouth Road, Ann Arbor, Michigan 48105, and Departments of Chemistry, and Cell Biology and Anatomy, University of Arizona, Tucson, Arizona 85721
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