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Ericson MD, Doering SR, Larson CM, Freeman KT, LaVoi TM, Donow HM, Santos RG, Cho RH, Koerperich ZM, Giulianotti MA, Pinilla C, Houghten RA, Haskell-Luevano C. Functional Mixture-Based Positional Scan Identifies a Library of Antagonist Tetrapeptide Sequences (LAtTeS) with Nanomolar Potency for the Melanocortin-4 Receptor and Equipotent with the Endogenous AGRP(86-132) Antagonist. J Med Chem 2021; 64:14860-14875. [PMID: 34592820 DOI: 10.1021/acs.jmedchem.1c01417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The melanocortin-4 receptor (MC4R) plays an important role in appetite. Agonist ligands that stimulate the MC4R decrease appetite, while antagonist compounds increase food consumption. Herein, a functional mixture-based positional scan identified novel MC4R antagonist sequences. Mixtures comprising a library of 12,960,000 tetrapeptides were screened in the presence and absence of the NDP-MSH agonist. These results led to the synthesis of 48 individual tetrapeptides, of which 40 were screened for functional activity at the melanocortin receptors. Thirteen compounds were found to possess nanomolar antagonist potency at the MC4R, with the general tetrapeptide sequence Ac-Aromatic-Basic-Aromatic-Basic-NH2. The most notable results include the identification of tetrapeptide 48 [COR1-25, Ac-DPhe(pI)-Arg-Nal(2')-Arg-NH2], an equipotent MC4R antagonist to agouti-related protein [AGRP(86-132)], more potent than miniAGRP(87-120), and possessing 15-fold selectivity for the MC4R versus the MC3R. These tetrapeptides may serve as leads for novel appetite-inducing therapies to treat states of negative energy balance, such as cachexia and anorexia.
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Affiliation(s)
- Mark D Ericson
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Skye R Doering
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Courtney M Larson
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Katie T Freeman
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Travis M LaVoi
- Florida International University, Port St. Lucie, Florida 34987, United States
| | - Haley M Donow
- Florida International University, Port St. Lucie, Florida 34987, United States
| | - Radleigh G Santos
- Nova Southeastern University, 3301 College Avenue, Fort Lauderdale, Florida 33314, United States
| | - Rachel H Cho
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Zoe M Koerperich
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Marc A Giulianotti
- Florida International University, Port St. Lucie, Florida 34987, United States
| | - Clemencia Pinilla
- Florida International University, Port St. Lucie, Florida 34987, United States
| | - Richard A Houghten
- Florida International University, Port St. Lucie, Florida 34987, United States
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry and Institute for Translation Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
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2
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Fleming KA, Freeman KT, Powers MD, Santos RG, Debevec G, Giulianotti MA, Houghten RA, Doering SR, Pinilla C, Haskell-Luevano C. Discovery of Polypharmacological Melanocortin-3 and -4 Receptor Probes and Identification of a 100-Fold Selective nM MC3R Agonist versus a μM MC4R Partial Agonist. J Med Chem 2019; 62:2738-2749. [PMID: 30741545 PMCID: PMC6463894 DOI: 10.1021/acs.jmedchem.9b00053] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The centrally expressed melanocortin-3 and melanocortin-4 receptors (MC3R and MC4R, respectively) are established targets to treat diseases of positive- and negative-energy homeostasis. We previously reported [ Doering , S. R. ; J. Med. Chem. 2017 , 60 , 4342 - 4357 ] mixture-based positional scanning approaches to identify dual MC3R agonist and MC4R antagonist tetrapeptides. Herein, 46 tetrapeptides were chosen for MC3R agonist screening selectivity profiles, synthesized, and pharmacologically characterized at the mouse melanocortin-1, -3, -4, and -5 receptors. Substitutions to the tetrapeptide template were selected solely based on MC3R agonist potency from the mixture-based screen. This study resulted in the discovery of compound 42 (Ac-Val-Gln-(pI)DPhe-DTic-NH2), a full MC3R agonist that is 100-fold selective for the MC3R over the μM MC4R partial agonist pharmacology. This compound represents a first-in-class MC3R selective agonist. This ligand will serve as a useful in vivo molecular probe for the investigation of the roles of the MC3R and MC4R in diseases of dysregulated energy homeostasis.
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Affiliation(s)
- Katlyn A. Fleming
- University of Minnesota, Department of Medicinal Chemistry, Minneapolis, Minnesota 55455, United States
| | - Katie T. Freeman
- University of Minnesota, Department of Medicinal Chemistry, Minneapolis, Minnesota 55455, United States
| | - Mike D. Powers
- University of Minnesota, Department of Medicinal Chemistry, Minneapolis, Minnesota 55455, United States
| | - Radleigh G. Santos
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida 34987, United States
| | - Ginamarie Debevec
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida 34987, United States
| | - Marc A. Giulianotti
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida 34987, United States
| | - Richard A. Houghten
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida 34987, United States
| | - Skye R. Doering
- University of Minnesota, Department of Medicinal Chemistry, Minneapolis, Minnesota 55455, United States
| | - Clemencia Pinilla
- To whom correspondence about the use of positional scanning libraries should be addressed at at Torrey Pines Institute for Molecular Studies
| | - Carrie Haskell-Luevano
- University of Minnesota, Department of Medicinal Chemistry, Minneapolis, Minnesota 55455, United States
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3
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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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Abstract
Melanocortins, adrenocorticotropic hormone (ACTH) and α-, β-, and γ-melanocyte-stimulating hormone (MSH) are produced in the placenta and secreted into embryos/fetuses. ACTH concentrations are higher in fetal plasma than in maternal plasma and peak at mid-gestation in rats, whereas ACTH production starts in the anterior lobe of the fetal pituitary at later stages. Melanocortin receptors (MC1-5R), receptors for ACTH and α-, β- and γ-MSH, are expressed in various adult organs. The specific function of these receptors has been well examined in the hypothalamic-pituitary-adrenocortical (HPA) axis and the HPA axis-like network in the skin, and anti-inflammatory effects for white blood cells have also been investigated. MC2R and/or MC5R are also expressed in the testis, lung, kidney, adrenal, liver, pancreas, brain and blood cells at different stages in mouse and rat embryos/fetuses. Melanocortins in embryos and fetuses promote maturation of the HPA axis and also contribute to the development of lung, testis, brain and blood cells. Recently, a unique ACTH function was revealed in fetuses: placental ACTH, which is secreted by the maternal leukemia inhibitory factor (LIF), and induces LIF secretion from fetal nucleated red blood cells. Finally, the maternal LIF-placental ACTH-fetal LIF signal relay regulates the LIF level and promotes neurogenesis in fetuses, which suggests that ACTH acts as a signal transducer or effector for fetal development in the maternal-fetal signal pathway.
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Affiliation(s)
- Eriko Simamura
- Department of Anatomy I, Kanazawa Medical University, Uchinada, Ishikawa, Japan
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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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6
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Miller CL, Murakami P, Ruczinski I, Ross RG, Sinkus M, Sullivan B, Leonard S. Two complex genotypes relevant to the kynurenine pathway and melanotropin function show association with schizophrenia and bipolar disorder. Schizophr Res 2009; 113:259-67. [PMID: 19502010 PMCID: PMC2855687 DOI: 10.1016/j.schres.2009.05.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 05/11/2009] [Accepted: 05/12/2009] [Indexed: 10/20/2022]
Abstract
Prior studies of mRNA expression, protein expression, and pathway metabolite levels have implicated dysregulation of the kynurenine pathway in the etiology of schizophrenia and bipolar disorder. Here we investigate whether genes involved in kynurenine pathway regulation might interact with genes that respond to kynurenine metabolites, to enhance risk for these psychiatric phenotypes. Candidate genes were selected from prior studies of genetic association, gene expression profiling and animal models. A single nucleotide polymorphism (SNP) in each of six genes, TDO2, HM74, HM74A, MCHR1, MCHR2 and MC5R, was tested for association with phenotype (475 Caucasians, 88 African Americans with schizophrenia; 97 Caucasians, 3 African Americans with bipolar disorder; 191 Caucasian, 49 African American controls). An A allele in HM74 was significantly associated with schizophrenia and with schizophrenia plus bipolar disorder combined, odds ratios (OR) of 1.48, p=0.011 and 1.50, p=0.007, respectively. Augmentation of disease risk was found for the complex genotype HM74[A,any]+MCHR1[T,any]+MCHR2[C,any] which conferred an OR maximal for the combined diagnostic category of schizophrenia plus bipolar disorder (1.70, p=0.003), carried by 30% of the cases. TDO2[CC]+MC5R[G, any]+MCHR2[GC] conferred an OR maximal for schizophrenia alone (4.84, p=0.005), carried by 8% of schizophrenia cases. The combined risk posed by these related, complex genotypes is greater than any identified single locus and may derive from co-regulation of the kynurenine pathway by interacting genes, a lack of adequate melanotropin-controlled sequestration of the kynurenine-derived pigments, or the production of melanotropin receptor ligands through kynurenine metabolism.
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Affiliation(s)
| | - Peter Murakami
- Department of Biostatistics, Johns Hopkins University, Baltimore, MD, USA
| | - Ingo Ruczinski
- Department of Biostatistics, Johns Hopkins University, Baltimore, MD, USA
| | - Randal G. Ross
- Department of Psychiatry, University of Colorado Health Sciences Center, Aurora, CO, USA
| | - Melissa Sinkus
- Department of Psychiatry, University of Colorado Health Sciences Center, Aurora, CO, USA
| | - Bernadette Sullivan
- Department of Psychiatry, University of Colorado Health Sciences Center, Aurora, CO, USA
| | - Sherry Leonard
- Department of Psychiatry, University of Colorado Health Sciences Center, Aurora, CO, USA
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7
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Rodrigues AR, Pignatelli D, Almeida H, Gouveia AM. Melanocortin 5 receptor activates ERK1/2 through a PI3K-regulated signaling mechanism. Mol Cell Endocrinol 2009; 303:74-81. [PMID: 19428994 DOI: 10.1016/j.mce.2009.01.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 01/19/2009] [Accepted: 01/20/2009] [Indexed: 11/24/2022]
Abstract
Melanocortin 5 receptor (MC5R) is a G protein coupled receptor (GPCR) with high affinity for alpha-melanocyte-stimulating hormone (alpha-MSH). To unravel some of the downstream cell-signaling pathways activated by this receptor, HEK293 cells were transiently and stably transfected with a vector encoding green fluorescent protein (GFP)-tagged MC5R. In these cells the receptor was correctly addressed to the cell surface and was functional, as shown by the MC5R-induced formation of intracellular cAMP. In fact, the MC5R agonist alpha-MSH induced a 10- or 16-fold increase (transient or stable cells, respectively) above the cAMP levels found in unstimulated cells. Moreover, in cells stably expressing MC5R-GFP, alpha-MSH promoted ERK1/2 phosphorylation in a dose-dependent manner (EC50=7.3 nM) with the maximal effect occurring after 5 min of agonist incubation. The signaling pathway conveyed through ERK1/2 is not linked to cAMP, since the phosphorylation of these kinases is unchanged by the inhibition of adenylyl cyclase. Also, ERK1/2 activation is not significantly affected by protein kinase A (PKA), protein kinase C (PKC) and protein kinase B or Akt (Akt/PKB) specific inhibitors. However, alpha-MSH-induced ERK1/2 activation is abolished by the phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and LY294002. Altogether, these findings demonstrate that MC5R signals through a PI3K-regulated Akt-independent pathway leading to downstream activation of ERK1/2. The involvement of these MAPK suggests that MC5R could be implicated in cellular proliferation or differentiation mechanisms.
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Affiliation(s)
- Adriana R Rodrigues
- Laboratory of Cell and Molecular Biology, Faculty of Medicine of Porto, Portugal
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8
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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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9
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Mayorov AV, Cai M, Palmer ES, Dedek MM, Cain JP, Van Scoy AR, Tan B, Vagner J, Trivedi D, Hruby VJ. Structure-activity relationships of cyclic lactam analogues of alpha-melanocyte-stimulating hormone (alpha-MSH) targeting the human melanocortin-3 receptor. J Med Chem 2008; 51:187-95. [PMID: 18088090 PMCID: PMC2587288 DOI: 10.1021/jm070461w] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A variety of dicarboxylic acid linkers introduced between the alpha-amino group of Pro(6) and the -amino group of Lys(10) of the cyclic lactam alpha-melanocyte-stimulating hormone (alpha-MSH)-derived Pro(6)-D-Phe(7)/D-Nal(2')(7)-Arg(8)-Trp(9)-Lys(10)-NH2 pentapeptide template lead to nanomolar range and selective hMC3R agonists and antagonists. Replacement of the Pro(6) residue and the dicarboxylic acid linker with 2,3-pyrazine-dicarboxylic acid furnished a highly selective nanomolar range hMC3R partial agonist (analogue 12, c[CO-2,3-pyrazine-CO-D-Phe-Arg-Trp-Lys]-NH2, EC50 = 27 nM, 70% max cAMP) and an hMC3R antagonist (analogue 13, c[CO-2,3-pyrazine-CO-D-Nal(2')-Arg-Trp-Lys]-NH2, IC50 = 23 nM). Modeling experiments suggest that 2,3-pyrazinedicarboxylic acid stabilizes a beta-turn-like structure with the D-Phe/D-Nal(2') residues, which explains the high potency of the corresponding peptides. Placement of a Nle residue in position 6 produced a hMC3R/hMC5R antagonist (analogue 15, c[CO-(CH 2)2-CO-Nle-D-Nal(2')-Arg-Trp-Lys]-NH2, IC50 = 12 and 17 nM, respectively), similarly to the previously described cyclic gamma-melanocyte-stimulating hormone (gamma-MSH)-derived hMC3R/hMC5R antagonists. These newly developed melanotropins will serve as critical biochemical tools for elucidating the full spectrum of functions performed by the physiologically important melanocortin-3 receptor.
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MESH Headings
- Binding, Competitive
- Cell Line
- Cyclic AMP/biosynthesis
- Humans
- Lactams/chemical synthesis
- Lactams/pharmacology
- Models, Molecular
- Peptides, Cyclic/chemical synthesis
- Peptides, Cyclic/chemistry
- Peptides, Cyclic/pharmacology
- Radioligand Assay
- Receptor, Melanocortin, Type 3/agonists
- Receptor, Melanocortin, Type 3/antagonists & inhibitors
- Receptor, Melanocortin, Type 3/chemistry
- Structure-Activity Relationship
- alpha-MSH/analogs & derivatives
- alpha-MSH/chemical synthesis
- alpha-MSH/pharmacology
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Affiliation(s)
| | - Minying Cai
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
| | - Erin S. Palmer
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
| | - Matthew M. Dedek
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
| | - James P. Cain
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
| | - April R. Van Scoy
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
| | - Bahar Tan
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
| | - Josef Vagner
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
| | - Dev Trivedi
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
| | - Victor J. Hruby
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
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Bednarek MA, MacNeil T, Tang R, Fong TM, Angeles Cabello M, Maroto M, Teran A. Analogs of α-melanocyte stimulating hormone with high agonist potency and selectivity at human melanocortin receptor 1b: The role of Trp9 in molecular recognition. Biopolymers 2008; 89:401-8. [DOI: 10.1002/bip.20863] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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11
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Bednarek MA, MacNeil T, Tang R, Fong TM, Angeles Cabello M, Maroto M, Teran A. Potent and Selective Peptide Agonists of ?-Melanocyte Stimulating Hormone (?MSH) Action at Human Melanocortin Receptor 5; their Synthesis and Biological Evaluation in vitro. Chem Biol Drug Des 2007; 69:350-5. [PMID: 17539827 DOI: 10.1111/j.1747-0285.2007.00513.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Melanocortin receptors (MC1-5R) and their endogenous ligands (melanocyte-stimulating hormones and adrenocorticotropic hormone) are involved in many physiological processes in humans. Of those receptors, the actions of MC5R are the least understood despite its broad presence in the numerous peripheral tissues and brain. In this study, we describe synthesis and pharmacological properties in vitro (receptor-binding affinity and agonist activity) of several cyclic analogs of alphaMSH which are potent agonists at hMC5R (EC(50) below 1 nM) and of enhanced receptor subtype selectivity (more than 2000-fold versus hMC1b,3R and about 70- to 200-fold versus hMC4R). These compounds are analogs of Ac-Nle(4)-cyclo[Asp(5)-His(6)-D-Nal(2')(7)-Pip(8)-Trp(9)-Lys(10)]-NH(2) (Pip: pipecolic acid) in which His(6) has been replaced with sterically hindered amino acids. They may be useful tools in the elucidation of the MC5R role in skin disorders and in immunomodulatory and in anti-inflammatory actions of alphaMSH.
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Affiliation(s)
- Maria A Bednarek
- Department of Medicinal Chemistry, Merck Research Laboratories, Rahway, NJ, USA.
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