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Ramos-Alvarez I, Lee L, Mantey SA, Jensen RT. Development and Characterization of a Novel, High-Affinity, Specific, Radiolabeled Ligand for BRS-3 Receptors. J Pharmacol Exp Ther 2019; 369:454-465. [PMID: 30971479 DOI: 10.1124/jpet.118.255141] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 04/05/2019] [Indexed: 02/06/2023] Open
Abstract
Bombesin (Bn) receptor subtype 3(BRS-3) is an orphan G-protein-coupled receptor of the Bn family, which does not bind any natural Bn peptide with high affinity. Receptor knockout studies show that the animals develop diabetes, obesity, altered temperature control, and other central nervous system (CNS)/endocrine/gastrointestinal changes. It is present in CNS, peripheral tissues, and tumors; however, its role in normal physiology/pathophysiology, as well as its receptor localization/pharmacology is largely unknown, in part due to the lack of a convenient, specific, direct radiolabeled ligand. This study was designed to address this problem and to develop and characterize a specific radiolabeled ligand for BRS-3. The peptide antagonist Bantag-1 had >10,000-fold selectivity for human BRS-3 (hBRS-3) over other mammalian Bn receptors (BnRs) [i.e., gastrin-releasing peptide receptor (GRPR) and neuromedin B receptor (NMBR)]. Using iodogen and basic conditions, it was radiolabeled to high specific activity (2200 Ci/mmol) and found to bind with high affinity/specificity to hBRS-3. Binding was saturable, rapid, and reversible. The ligand only interacted with known BRS-3 ligands, and not with other specific GRPR/NMBR ligands or ligands for unrelated receptors. The magnitude of 125I-Bantag-1 binding correlated with BRS-3 mRNA expression and the magnitude of activation of phospholipase C in lung cancer cells, as well as readily identifying BRS-3 in lung cancer cells and normal tissues, allowing the direct assessment of BRS-3 receptor pharmacology/numbers on cells containing BRS-3 with other BnRs, which is usually the case. This circumvents the need for subtraction assays, which are now frequently used to assess BRS-3 indirectly using radiolabeled pan-ligands, which interact with all BnRs.
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Affiliation(s)
- Irene Ramos-Alvarez
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Lingaku Lee
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Samuel A Mantey
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Robert T Jensen
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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Tang H, Shu C, Chen H, Zhang X, Zang Z, Deng C. Constitutively active BRS3 is a genuinely orphan GPCR in placental mammals. PLoS Biol 2019; 17:e3000175. [PMID: 30840614 PMCID: PMC6422423 DOI: 10.1371/journal.pbio.3000175] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 03/18/2019] [Accepted: 02/19/2019] [Indexed: 11/19/2022] Open
Abstract
G protein-coupled receptors (GPCRs) play an important role in physiology and disease and represent the most productive drug targets. Orphan GPCRs, with their endogenous ligands unknown, were considered a source of drug targets and consequently attract great interest to identify their endogenous cognate ligands for deorphanization. However, a contrary view to the ubiquitous existence of endogenous ligands for every GPCR is that there might be a significant overlooked fraction of orphan GPCRs that function constitutively in a ligand-independent manner only. Here, we investigated the evolution of the bombesin receptor-ligand family in vertebrates in which one member-bombesin receptor subtype-3 (BRS3)-is a potential orphan GPCR. With analysis of 17 vertebrate BRS3 structures and 10 vertebrate BRS3 functional data, our results demonstrated that nonplacental vertebrate BRS3 still connects to the original ligands-neuromedin B (NMB) and gastrin-releasing peptide (GRP)-because of adaptive evolution, with significantly changed protein structure, especially in three altered key residues (Q127R, P205S, and R294H) originally involved in ligand binding/activation, whereas the placental mammalian BRS3 lost the binding affinity to NMB/GRP and constitutively activates Gs/Gq/G12 signaling in a ligand-independent manner. Moreover, the N terminus of placental mammalian BRS3 underwent positive selection, exhibiting significant structural differences compared to nonplacental vertebrate BRS3, and this domain plays an important role in constitutive activity of placental mammalian BRS3. In conclusion, constitutively active BRS3 is a genuinely orphan GPCR in placental mammals, including human. To our knowledge, this study identified the first example that might represent a new group of genuinely orphan GPCRs that will never be deorphanized by the discovery of a natural ligand and provided new perspectives in addition to the current ligand-driven GPCR deorphanization.
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Affiliation(s)
- Huihao Tang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Chuanjun Shu
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
- Department of Bioinformatics, College of Biomedical Engineering and Information, Nanjing Medical University, Nanjing, China
| | - Haidi Chen
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xiaojing Zhang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Zhuqing Zang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Cheng Deng
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
- * E-mail:
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González N, Moreno P, Jensen RT. Bombesin receptor subtype 3 as a potential target for obesity and diabetes. Expert Opin Ther Targets 2015; 19:1153-70. [PMID: 26066663 DOI: 10.1517/14728222.2015.1056154] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Diabetes mellitus and obesity are important health issues; increasing in prevalence, both in the USA and globally. There are only limited pharmacological treatments, and although bariatric surgery is effective, new effective pharmacologic treatments would be of great value. This review covers one area of increasing interest that could yield new novel treatments of obesity/diabetes mellitus. It involves recognition of the central role the G-protein-coupled receptor, bombesin receptor subtype 3 (BRS-3) plays in energy/glucose metabolism. AREAS COVERED Since the initial observation that BRS-3 knockout mice develop obesity, hypertension, impaired glucose metabolism and hyperphagia, there have been numerous studies of the mechanisms involved and the development of selective BRS-3 agonists/antagonists, which have marked effects on body weight, feeding and glucose/insulin homeostasis. In this review, each of these areas is briefly reviewed. EXPERT OPINION BRS-3 plays an important role in glucose/energy homeostasis. The development of potent, selective BRS-3 agonists demonstrates promise as a novel approach to treat obesity/diabetic states. One important question that needs to be addressed is whether BRS-3 agonists need to be centrally acting. This is particularly important in light of recent animal and human studies that report transient cardiovascular side effects with centrally acting oral BRS agonists.
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Affiliation(s)
- Nieves González
- The Autonomous University of Madrid, IIS-Jiménez Díaz Foundation, Renal, Vascular and Diabetes Research Laboratory, Spanish Biomedical Research Network in Diabetes and, Associated Metabolic Disorders (CIBERDEM) , Madrid , Spain
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Abstract
PURPOSE OF REVIEW This review summarizes the results of recent studies regarding the biology and pharmacology of novel synthetic agonists and antagonists of the bombesin receptor subtype-3 (BRS-3). RECENT FINDINGS All three mammalian bombesin receptors including gastrin-releasing peptide receptor, the neuromedin B receptor, and the BRS-3 have been shown to regulate energy balance and appetite and satiety. Studies indicate that the orphan BRS-3 is an important regulator of body weight, energy expenditure, and glucose homeostasis. Endogenous bombesin-like peptides bombesin, gastrin-releasing peptide, and neuromedin B receptor do not bind to BRS-3 and the endogenous BRS-3 ligand remains unknown. The novel synthesis of selective, high-affinity BRS-3 agonists and antagonists has recently been accomplished and showed that BRS-3 regulates energy balance independent of other established pathways and glucose-stimulated insulin secretion in the pancreatic islet cells. The availability of new BRS-3 selective agonists and antagonists will facilitate further elucidation of its role in energy homeostasis, and provides a potential approach for the pharmacological treatment of obesity and type 2 diabetes. SUMMARY The native ligand of the G protein-coupled BRS-3 has not been identified as of now. However, novel synthesis of small-molecule, high-affinity agonists and antagonists on the BRS-3 was used in the recent studies and demonstrated an important role of BRS-3 in the regulation of energy homeostasis and glucose metabolism.
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Affiliation(s)
- Ishita D Majumdar
- Section of Gastroenterology, Boston University School of Medicine, Boston, Massachusetts, USA
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Abstract
Studies on bombesin-like peptides (BLP) and their respective mammalian receptors (Bn-r) have demonstrated a significant biological impact on a broad array of physiological and pathophysiological conditions. Pharmacological experiments in vitro and in vivo as well as utilization of genetic rodent models of the gastrin-releasing peptide receptor (GRP-R/BB2-receptor), neuromedin B receptor (NMB-R/BB1-receptor), and the bombesin receptor subtype-3 (BRS-3/BB3-receptor) further delineated their role in health and disease. All three mammalian bombesin receptors have been shown to possess some role in the regulation of energy balance and appetite and satiety. Compelling experimental evidence has accumulated indicating that the orphan BRS-3 is an important regulator of body weight, energy expenditure, and glucose homeostasis. BRS-3 possesses no high affinity to the endogenous bombesin-like peptides (BLP) bombesin, GRP, and NMB, and its endogenous ligand remains unknown. Recently, the synthesis of novel, selective high-affinity BRS-3 agonists and antagonists has been accomplished and has demonstrated that BRS-3 regulates energy balance independent of other established pathways. Accordingly, the availability of new BRS-3 selective agonists and antagonists will facilitate further elucidation of its role in energy homeostasis and provides a potential approach for the pharmacological treatment of obesity.
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Moody TW, Sancho V, di Florio A, Nuche-Berenguer B, Mantey S, Jensen RT. Bombesin receptor subtype-3 agonists stimulate the growth of lung cancer cells and increase EGF receptor tyrosine phosphorylation. Peptides 2011; 32:1677-84. [PMID: 21712056 PMCID: PMC3152616 DOI: 10.1016/j.peptides.2011.06.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 06/13/2011] [Accepted: 06/13/2011] [Indexed: 10/18/2022]
Abstract
The effects of bombesin receptor subtype-3 (BRS-3) agonists were investigated on lung cancer cells. The BRS-3 agonist (DTyr(6), (Ala(11), Phe(13), Nle(14)) bombesin(6-14) (BA1), but not gastrin releasing peptide (GRP) or neuromedin B (NMB) increased significantly the clonal growth of NCI-H1299 cells stably transfected with BRS-3 (NCI-H1299-BRS-3). Also, BA1 addition to NCI-H727 or NCI-H1299-BRS-3 cells caused Tyr(1068) phosphorylation of the epidermal growth factor receptor (EGFR). Similarly, (DTyr(6), R-Apa(11), Phe(13), Nle(14)) bombesin(6-14) (BA2) and (DTyr(6), R-Apa(11), 4-Cl,Phe(13), Nle(14)) bombesin(6-14) (BA3) but not gastrin releasing peptide (GRP) or neuromedin B (NMB) caused EGFR transactivation in NCI-H1299-BRS-3 cells. BA1-induced EGFR or ERK tyrosine phosphorylation was not inhibited by addition of BW2258U89 (BB(2)R antagonist) or PD168368 (BB(1)R antagonist) but was blocked by (DNal-Cys-Tyr-DTrp-Lys-Val-Cys-Nal)NH(2) (BRS-3 ant.). The BRS-3 ant. reduced clonal growth of NCI-H1299-BRS-3 cells. BA1, BA2, BA3 and BRS-3 ant. inhibit specific (125)I-BA1 binding to NCI-H1299-BRS-3 cells with an IC(50) values of 1.1, 21, 15 and 750nM, respectively. The ability of BRS-3 to regulate EGFR transactivation in NCI-H1299-BRS-3 cells was reduced by AG1478 or gefitinib (EGFR tyrosine kinase inhibitors), GM6001 (matrix metalloprotease inhibitor), PP2 (Src inhibitor), N-acetylcysteine (anti-oxidant), Tiron (superoxide scavenger) and DPI (NADPH oxidase inhibitor). These results demonstrate that BRS-3 agonists may stimulate lung cancer growth as a result of EGFR transactivation and that the transactivation is regulated by BRS-3 in a Src-, reactive oxygen and matrix metalloprotease-dependent manner.
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Affiliation(s)
- Terry W Moody
- Department of Health and Human Services, National Cancer Institute, Center for Cancer Research, Office of Director, Bethesda, MD 20892, USA.
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Pyridinesulfonylureas and pyridinesulfonamides as selective bombesin receptor subtype-3 (BRS-3) agonists. Bioorg Med Chem Lett 2011; 21:2040-3. [PMID: 21354793 DOI: 10.1016/j.bmcl.2011.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 02/02/2011] [Accepted: 02/03/2011] [Indexed: 10/18/2022]
Abstract
Bombesin receptor subtype-3 (BRS-3) is an orphan G-protein coupled receptor belonging to the subfamily of bombesin-like receptors. BRS-3 is implicated in the development of obesity and diabetes. We report here small-molecule agonists that are based on a 4-(alkylamino)pyridine-3-sulfonamide core. We describe the discovery of 2a, which has mid-nanomolar potency, selectivity for human BRS-3 versus the other bombesin-like receptors, and good bioavailability.
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Sebhat IK, Franklin C, Lo MMC, Chen D, Jewell JP, Miller R, Pang J, Palyha O, Kan Y, Kelly TM, Guan XM, Marsh DJ, Kosinski JA, Metzger JM, Lyons K, Dragovic J, Guzzo PR, Henderson AJ, Reitman ML, Nargund RP, Wyvratt MJ, Lin LS. Discovery of MK-5046, a Potent, Selective Bombesin Receptor Subtype-3 Agonist for the Treatment of Obesity. ACS Med Chem Lett 2011; 2:43-7. [PMID: 24900253 DOI: 10.1021/ml100196d] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Accepted: 10/06/2010] [Indexed: 11/29/2022] Open
Abstract
We report the development and characterization of compound 22 (MK-5046), a potent, selective small molecule agonist of BRS-3 (bombesin receptor subtype-3). In pharmacological testing using diet-induced obese mice, compound 22 caused mechanism-based, dose-dependent reductions in food intake and body weight.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Peter R. Guzzo
- AMRI, 26 Corporate Circle, Albany, New York 12212, United States
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Sancho V, Moody TW, Mantey SA, Di Florio A, Uehara H, Coy DH, Jensen RT. Pharmacology of putative selective hBRS-3 receptor agonists for human bombesin receptors (BnR): affinities, potencies and selectivity in multiple native and BnR transfected cells. Peptides 2010; 31:1569-78. [PMID: 20438784 PMCID: PMC2905478 DOI: 10.1016/j.peptides.2010.04.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 04/23/2010] [Accepted: 04/23/2010] [Indexed: 11/28/2022]
Abstract
The orphan receptor, bombesin receptor subtype-3(BRS-3) is a G-protein-coupled receptor classified in the bombesin (Bn) receptor family because of its high homology (47-51%) with other members of this family [gastrin-releasing peptide receptor [GRPR] and neuromedin B receptor [NMBR]]. There is increasing interest in BRS-3, because primarily from receptor knockout studies, it seems important in energy metabolism, glucose control, insulin secretion, motility and tumor growth. Pharmacological tools to study the role of BRS-3 in physiology/pathophysiology are limited because the natural ligand is unknown and BRS-3 has low affinity for all naturally occurring Bn-related peptides. However, a few years ago a synthetic high-affinity agonist [dTyr(6),betaAla(11),Phe(13),Nle(14)]Bn-(6-14) was described but was nonselective for BRS-3 over other Bn receptors. Based on this peptide, in various studies a number of putative selective, high-potency hBRS-3 agonists were described, however the results on their selectivity are conflicting in a number of cases. The purpose of the present study was to thoroughly study the pharmacology of four of the most select/potent putative hBRS-3 agonists (#2-4, 16a). Each was studied in multiple well-characterized Bn receptor-transfected cells and native Bn receptor bearing cells, using binding studies, alterations in cellular signaling (PLC, PKD) and changes in cellular function(growth). Two peptides (#2, #3) had nM affinities/potencies for hBRS-3, peptide #4 had low affinity/potency, and peptide #16a very low (>3000 nM). Peptide#3 had the highest selectivity for hBRS-3 (100-fold), whereas #2, 4 had lower selectivity. Peptide #16a's selectivity could not be determined because of its low affinity/potencies for all hBn receptors. These results show that peptide #3 is the preferred hBRS-3 agonist for studies at present, although its selectivity of only 100-fold may limit its utility in some cases. This study underscores the importance of full pharmacological characterization of newly reported selective agonists.
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Affiliation(s)
- Veronica Sancho
- Digestive Diseases Branch, NIDDK, and Department of Health and Human Services, National Institutes of Health, Bethesda, Maryland 20892-1804
| | - Terry W. Moody
- NCI Office of the Director, CCR, NCI and Department of Health and Human Services, National Institutes of Health, Bethesda, Maryland 20892-1804
| | - Samuel A. Mantey
- Digestive Diseases Branch, NIDDK, and Department of Health and Human Services, National Institutes of Health, Bethesda, Maryland 20892-1804
| | - Alessia Di Florio
- Digestive Diseases Branch, NIDDK, and Department of Health and Human Services, National Institutes of Health, Bethesda, Maryland 20892-1804
| | - Hirotsugu Uehara
- Digestive Diseases Branch, NIDDK, and Department of Health and Human Services, National Institutes of Health, Bethesda, Maryland 20892-1804
| | - David H. Coy
- Peptide Research Laboratories, Department of Medicine, Tulane Health Sciences Center, New Orleans, Louisiana 70112-2699
| | - Robert T. Jensen
- Digestive Diseases Branch, NIDDK, and Department of Health and Human Services, National Institutes of Health, Bethesda, Maryland 20892-1804
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Furutani N, Hondo M, Tsujino N, Sakurai T. Activation of Bombesin Receptor Subtype-3 Influences Activity of Orexin Neurons by Both Direct and Indirect Pathways. J Mol Neurosci 2010; 42:106-11. [DOI: 10.1007/s12031-010-9382-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Accepted: 04/20/2010] [Indexed: 12/01/2022]
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Liu J, He S, Jian T, Dobbelaar PH, Sebhat IK, Lin LS, Goodman A, Guo C, Guzzo PR, Hadden M, Henderson AJ, Pattamana K, Ruenz M, Sargent BJ, Swenson B, Yet L, Tamvakopoulos C, Peng Q, Pan J, Kan Y, Palyha O, Kelly TM, Guan XM, Howard AD, Marsh DJ, Metzger JM, Reitman ML, Wyvratt MJ, Nargund RP. Synthesis and SAR of derivatives based on 2-biarylethylimidazole as bombesin receptor subtype-3 (BRS-3) agonists for the treatment of obesity. Bioorg Med Chem Lett 2010; 20:2074-7. [DOI: 10.1016/j.bmcl.2010.02.076] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 02/16/2010] [Accepted: 02/18/2010] [Indexed: 10/19/2022]
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Discovery of substituted biphenyl imidazoles as potent, bioavailable bombesin receptor subtype-3 agonists. Bioorg Med Chem Lett 2010; 20:1913-7. [DOI: 10.1016/j.bmcl.2010.01.154] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 01/21/2010] [Accepted: 01/27/2010] [Indexed: 11/22/2022]
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Regulation of energy homeostasis by bombesin receptor subtype-3: selective receptor agonists for the treatment of obesity. Cell Metab 2010; 11:101-12. [PMID: 20096642 DOI: 10.1016/j.cmet.2009.12.008] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 09/02/2009] [Accepted: 12/18/2009] [Indexed: 01/04/2023]
Abstract
Bombesin receptor subtype 3 (BRS-3) is a G protein coupled receptor whose natural ligand is unknown. We developed potent, selective agonist (Bag-1, Bag-2) and antagonist (Bantag-1) ligands to explore BRS-3 function. BRS-3-binding sites were identified in the hypothalamus, caudal brainstem, and several midbrain nuclei that harbor monoaminergic cell bodies. Antagonist administration increased food intake and body weight, whereas agonists increased metabolic rate and reduced food intake and body weight. Prolonged high levels of receptor occupancy increased weight loss, suggesting a lack of tachyphylaxis. BRS-3 agonist effectiveness was absent in Brs3(-/Y) (BRS-3 null) mice but was maintained in Npy(-/-)Agrp(-/-), Mc4r(-/-), Cnr1(-/-), and Lepr(db/db) mice. In addition, Brs3(-/Y) mice lost weight upon treatment with either a MC4R agonist or a CB1R inverse agonist. These results demonstrate that BRS-3 has a role in energy homeostasis that complements several well-known pathways and that BRS-3 agonists represent a potential approach to the treatment of obesity.
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Gbahou F, Holst B, Schwartz TW. Molecular Basis for Agonism in the BB3 Receptor: An Epitope Located on the Interface of Transmembrane-III, -VI, and -VII. J Pharmacol Exp Ther 2010; 333:51-9. [DOI: 10.1124/jpet.109.162131] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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Discovery of small molecule agonists for the bombesin receptor subtype 3 (BRS-3) based on an omeprazole lead. Bioorg Med Chem Lett 2008; 18:5451-5. [DOI: 10.1016/j.bmcl.2008.09.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 09/05/2008] [Accepted: 09/08/2008] [Indexed: 11/23/2022]
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Jensen RT, Battey JF, Spindel ER, Benya RV. International Union of Pharmacology. LXVIII. Mammalian bombesin receptors: nomenclature, distribution, pharmacology, signaling, and functions in normal and disease states. Pharmacol Rev 2008; 60:1-42. [PMID: 18055507 PMCID: PMC2517428 DOI: 10.1124/pr.107.07108] [Citation(s) in RCA: 395] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The mammalian bombesin receptor family comprises three G protein-coupled heptahelical receptors: the neuromedin B (NMB) receptor (BB(1)), the gastrin-releasing peptide (GRP) receptor (BB(2)), and the orphan receptor bombesin receptor subtype 3 (BRS-3) (BB(3)). Each receptor is widely distributed, especially in the gastrointestinal (GI) tract and central nervous system (CNS), and the receptors have a large range of effects in both normal physiology and pathophysiological conditions. The mammalian bombesin peptides, GRP and NMB, demonstrate a broad spectrum of pharmacological/biological responses. GRP stimulates smooth muscle contraction and GI motility, release of numerous GI hormones/neurotransmitters, and secretion and/or hormone release from the pancreas, stomach, colon, and numerous endocrine organs and has potent effects on immune cells, potent growth effects on both normal tissues and tumors, potent CNS effects, including regulation of circadian rhythm, thermoregulation; anxiety/fear responses, food intake, and numerous CNS effects on the GI tract as well as the spinal transmission of chronic pruritus. NMB causes contraction of smooth muscle, has growth effects in various tissues, has CNS effects, including effects on feeding and thermoregulation, regulates thyroid-stimulating hormone release, stimulates various CNS neurons, has behavioral effects, and has effects on spinal sensory transmission. GRP, and to a lesser extent NMB, affects growth and/or differentiation of various human tumors, including colon, prostate, lung, and some gynecologic cancers. Knockout studies show that BB(3) has important effects in energy balance, glucose homeostasis, control of body weight, lung development and response to injury, tumor growth, and perhaps GI motility. This review summarizes advances in our understanding of the biology/pharmacology of these receptors, including their classification, structure, pharmacology, physiology, and role in pathophysiological conditions.
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Affiliation(s)
- R T Jensen
- Digestive Diseases Branch, National Institute of Diabetes Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.
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Gonzalez N, Moody TW, Igarashi H, Ito T, Jensen RT. Bombesin-related peptides and their receptors: recent advances in their role in physiology and disease states. Curr Opin Endocrinol Diabetes Obes 2008; 15:58-64. [PMID: 18185064 PMCID: PMC2631407 DOI: 10.1097/med.0b013e3282f3709b] [Citation(s) in RCA: 152] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW Mammalian bombesin-related peptides, gastrin-releasing peptide and neuromedin B actions are mediated by two receptors (BB1-receptor, BB2-receptor), which are closely related to the orphan receptor BRS-3 (BB3-receptor). The purpose of this review is to highlight advances in the understanding of these peptides in physiology/disease states. RECENT FINDINGS Pharmacologic/receptor-knockout studies show involvement of these receptors in a number of new processes/diseases. Neuromedin B/BB1-receptor is an important physiological regulator of pituitary-thyroid function; in mediating behavior, especially feas/anxiety; in mediating satiety through different cascades than gastrin-releasing peptide/BB2 receptors and for its autocrine tumor-growth effects. Gastrin-releasing peptide/BB2-receptor plays important roles in mediating signals for pruritus, lung development/injury, small intestinal mucosal defense, and central nervous system processes such as learning/memory. The signaling mechanisms of its potent growth effects are being elucidated and their possible therapeutic targets identified. BB3-receptor knockout mice provided insights for their obesity/glucose intolerance and demonstrated that this receptor may be important in the lung response to injury, tumor growth and gastrointestinal motility. Each receptor is frequently overexpressed in human tumors and has potent growth effects. This effect is being explored to develop new antitumor treatments, such as bombesin-receptor ligands conjugated to cytotoxic agents. SUMMARY This receptor family is involved in an increasing number of central nervous system/peripheral processes physiologically and in disease states, and increased understanding of its role may lead to novel treatments.
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Affiliation(s)
- Nieves Gonzalez
- Digestive Diseases Branch, National Institutes of Health, Bethesda, Maryland 20892, USA
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Gonzalez N, Hocart SJ, Portal-Nuñez S, Mantey SA, Nakagawa T, Zudaire E, Coy DH, Jensen RT. Molecular basis for agonist selectivity and activation of the orphan bombesin receptor subtype 3 receptor. J Pharmacol Exp Ther 2007; 324:463-74. [PMID: 18006692 DOI: 10.1124/jpet.107.132332] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bombesin receptor subtype (BRS)-3, a G-protein-coupled orphan receptor, shares 51% identity with the mammalian bombesin (Bn) receptor for gastrin-releasing peptide. There is increasing interest in BRS-3 because it is important in energy metabolism, glucose control, motility, and tumor growth. BRS-3 has low affinity for all Bn-related peptides; however, recently synthetic high-affinity agonists, [d-Tyr(6)/d-Phe(6),betaAla(11),Phe(13),Nle(14)]Bn-(6-14), were described, but they are nonselective for BRS-3 over other Bn receptors. Based on these peptides, three BRS-3-selective ligands were developed: peptide 2, [d-Tyr(6)(R)-3-amino-propionic acid(11),Phe(13),Nle(14)]Bn(6-14); peptide 3, [d-Tyr(6),(R)-Apa(11),4Cl-Phe(13),Nle(14)]Bn(6-14); and peptide 4, acetyl-Phe-Trp-Ala-His-(tBzl)-piperidine-3 carboxylic acid-Gly-Arg-NH(2). Their molecular determinants of selectivity/high affinity for BRS-3 are unknown. To address this, we used a chimeric/site mutagenesis approach. Substitution of extracellular domain 2 (EC2) of BRS-3 by the comparable gastrin-releasing peptide receptor (GRPR) domain decreased 26-, 4-, and 0-fold affinity for peptides 4, 3, and 2. Substitution of EC3 decreased affinity 4-, 11-, and 0-fold affinity for peptides 2 to 4. Ten-point mutations in the EC2 and adjacent transmembrane regions (TM2) 2 and 3 of BRS-3 were made. His107 (EC2-BRS-3) for lysine (H107K) (EC2-GRPR) decreased affinity (25- and 0-fold) for peptides 4 and 1; however, it could not be activated by either peptide. Its combination with Val101 (TM2), Gly112 (EC2), and Arg127 (TM3) resulted in complete loss-of-affinity of peptide 4. Receptor-modeling showed that each of these residues face inward and are within 4 A of the binding pocket. These results demonstrate that Val101, His107, Gly112, and Arg127 in the EC2/adjacent upper TMs of BRS-3 are critical for the high BRS3 selectivity of peptide 4. His107 in EC2 is essential for BRS-3 activation, suggesting amino-aromatic ligand/receptor interactions with peptide 4 are critical for both binding and activation. Furthermore, these result demonstrate that even though these three BRS-3-selective agonists were developed from the same template peptide, [d-Phe(6),betaAla(11),Phe(13),Nle(14)]Bn-(6-14), their molecular determinants of selectivity/high affinity varied considerably.
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Affiliation(s)
- Nieves Gonzalez
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Heath, Building 10, Room 9C-103, 10 Center Dr. MSC 1804, Bethesda, MD 20892-1804, USA
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Mantey SA, Gonzalez N, Schumann M, Pradhan TK, Shen L, Coy DH, Jensen RT. Identification of Bombesin Receptor Subtype-Specific Ligands: Effect ofN-Methyl Scanning, Truncation, Substitution, and Evaluation of Putative Reported Selective Ligands. J Pharmacol Exp Ther 2006; 319:980-9. [PMID: 16943256 DOI: 10.1124/jpet.106.107011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mammalian bombesin (Bn) receptors include the gastrin-releasing peptide receptor, neuromedin B receptor, and bombesin receptor subtype 3 (BRS-3). These receptors are involved in a variety of physiological/pathologic processes, including thermoregulation, secretion, motility, chemotaxis, and mitogenic effects on both normal and malignant cells. Tumors frequently overexpress these receptors, and their presence is now used for imaging and receptor-mediated cytotoxicity. For these reasons, there is an increased need to develop synthetic, selective receptor subtype-specific ligands, especially agonists for these receptors. In this study, we used a number of strategies to identify useful receptor subtype-selective ligands, including synthesizing new analogs (N-methyl-substituted constrained analogs, truncations, and substitutions) in [d-Tyr(6),betaAla(11),Phe(13),Nle(14)]Bn(6-14), which has high affinity for all Bn receptors and is metabolically stable, as well as completely pharmacologically characterized analogs recently reported to be selective for these receptors in [Ca(2+)](i) assays. Affinities and potencies of each analog were determined for each human Bn receptor subtype. N-Methyl substitutions in positions 14, 12, 11, 10, 9, and 8 did not result in selective analogs, with the exception of position 11, which markedly decreased affinity/potency. N-Terminal truncations or position 12 substitutions did not increase selectivity as previously reported by others. Of the four shortened analogs of [d-Phe(6),betaAla(11),Phe(13),Nle(14)]Bn(6-14) reported to be potent selective BRS-3 ligands on [Ca(2+)](i) assays, only AcPhe,Trp,Ala,His(tauBzl),Nip,Gly,Arg-NH(2) had moderate selectivity for hBRS-3; however, it was less selective than previously reported Apa(11) analogs, demonstrating these are still the most selective BRS-3 analogs available. However, both of these analogs should be useful templates to develop more selective BRS-3 ligands.
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Affiliation(s)
- Samuel A Mantey
- DHHS/NIH, NIDDK, DDB, Bldg. 10, Rm. 9C103, 31 Center Drive, Bethesda, MD 20892, USA
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