1
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Bentsen MA, Rausch DM, Mirzadeh Z, Muta K, Scarlett JM, Brown JM, Herranz-Pérez V, Baquero AF, Thompson J, Alonge KM, Faber CL, Kaiyala KJ, Bennett C, Pyke C, Ratner C, Egerod KL, Holst B, Meek TH, Kutlu B, Zhang Y, Sparso T, Grove KL, Morton GJ, Kornum BR, García-Verdugo JM, Secher A, Jorgensen R, Schwartz MW, Pers TH. Transcriptomic analysis links diverse hypothalamic cell types to fibroblast growth factor 1-induced sustained diabetes remission. Nat Commun 2020; 11:4458. [PMID: 32895383 PMCID: PMC7477234 DOI: 10.1038/s41467-020-17720-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/15/2020] [Indexed: 12/26/2022] Open
Abstract
In rodent models of type 2 diabetes (T2D), sustained remission of hyperglycemia can be induced by a single intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1), and the mediobasal hypothalamus (MBH) was recently implicated as the brain area responsible for this effect. To better understand the cellular response to FGF1 in the MBH, we sequenced >79,000 single-cell transcriptomes from the hypothalamus of diabetic Lepob/ob mice obtained on Days 1 and 5 after icv injection of either FGF1 or vehicle. A wide range of transcriptional responses to FGF1 was observed across diverse hypothalamic cell types, with glial cell types responding much more robustly than neurons at both time points. Tanycytes and ependymal cells were the most FGF1-responsive cell type at Day 1, but astrocytes and oligodendrocyte lineage cells subsequently became more responsive. Based on histochemical and ultrastructural evidence of enhanced cell-cell interactions between astrocytes and Agrp neurons (key components of the melanocortin system), we performed a series of studies showing that intact melanocortin signaling is required for the sustained antidiabetic action of FGF1. These data collectively suggest that hypothalamic glial cells are leading targets for the effects of FGF1 and that sustained diabetes remission is dependent on intact melanocortin signaling.
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MESH Headings
- Agouti-Related Protein/metabolism
- Animals
- Astrocytes/drug effects
- Astrocytes/metabolism
- Blood Glucose/analysis
- Cell Communication
- Cell Nucleus/drug effects
- Cell Nucleus/metabolism
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/diet therapy
- Diabetes Mellitus, Experimental/etiology
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/etiology
- Diabetes Mellitus, Type 2/pathology
- Diet, High-Fat/adverse effects
- Dietary Sucrose/administration & dosage
- Dietary Sucrose/adverse effects
- Fibroblast Growth Factor 1/administration & dosage
- Humans
- Hypoglycemic Agents/administration & dosage
- Hypothalamus/cytology
- Hypothalamus/drug effects
- Hypothalamus/pathology
- Injections, Intraventricular
- Leptin/genetics
- Male
- Melanocortins/metabolism
- Melanocyte-Stimulating Hormones/administration & dosage
- Mice
- Mice, Knockout
- Neurons/drug effects
- Neurons/metabolism
- Oligodendroglia/drug effects
- Oligodendroglia/metabolism
- RNA-Seq
- Receptor, Melanocortin, Type 4/genetics
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Melanocortin/metabolism
- Recombinant Proteins/administration & dosage
- Remission Induction/methods
- Signal Transduction/drug effects
- Single-Cell Analysis
- Stereotaxic Techniques
- Transcriptome/drug effects
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Affiliation(s)
- Marie A Bentsen
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Dylan M Rausch
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Kenjiro Muta
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
- Chakri Naruebodindra Medical Institute, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Jarrad M Scarlett
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
- Department of Pediatric Gastroenterology and Hepatology, Seattle Children's Hospital, Seattle, WA, USA
| | - Jenny M Brown
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
| | - Vicente Herranz-Pérez
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, Valencia, Spain
- Predepartamental Unit of Medicine, Jaume I University, Castelló de la Plana, Spain
| | - Arian F Baquero
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Jonatan Thompson
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kimberly M Alonge
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
| | - Chelsea L Faber
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
| | - Karl J Kaiyala
- Department of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, WA, USA
| | - Camdin Bennett
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Charles Pyke
- Pathology & Imaging, Global Discovery and Development Sciences, Novo Nordisk A/S, Maaloev, Denmark
| | - Cecilia Ratner
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kristoffer L Egerod
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Birgitte Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas H Meek
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Burak Kutlu
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Yu Zhang
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Thomas Sparso
- Bioinformatics and Data Mining, Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark
| | - Kevin L Grove
- Obesity Research Unit, Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA
| | - Gregory J Morton
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA
| | - Birgitte R Kornum
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | | | - Anna Secher
- Diabetes Research, Global Drug Discovery, Novo Nordisk A/S, Maaloev, Denmark
| | - Rasmus Jorgensen
- Diabetes Research, Global Drug Discovery, Novo Nordisk A/S, Maaloev, Denmark
- Cytoki Pharma, Copenhagen, Denmark
| | - Michael W Schwartz
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA, USA.
| | - Tune H Pers
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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2
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Dore R, Levata L, Gachkar S, Jöhren O, Mittag J, Lehnert H, Schulz C. The thermogenic effect of nesfatin-1 requires recruitment of the melanocortin system. J Endocrinol 2017; 235:111-122. [PMID: 28851749 DOI: 10.1530/joe-17-0151] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 08/15/2017] [Indexed: 12/13/2022]
Abstract
Nesfatin-1 is a bioactive polypeptide expressed both in the brain and peripheral tissues and involved in the control of energy balance by reducing food intake. Central administration of nesfatin-1 significantly increases energy expenditure, as demonstrated by a higher dry heat loss; yet, the mechanisms underlying the thermogenic effect of central nesfatin-1 remain unknown. Therefore, in this study, we sought to investigate whether the increase in energy expenditure induced by nesfatin-1 is mediated by the central melanocortin pathway, which was previously reported to mediate central nesfatin-1´s effects on feeding and numerous other physiological functions. With the application of direct calorimetry, we found that intracerebroventricular nesfatin-1 (25 pmol) treatment increased dry heat loss and that this effect was fully blocked by simultaneous administration of an equimolar dose of the melanocortin 3/4 receptor antagonist, SHU9119. Interestingly, the nesfatin-1-induced increase in dry heat loss was positively correlated with body weight loss. In addition, as assessed with thermal imaging, intracerebroventricular nesfatin-1 (100 pmol) increased interscapular brown adipose tissue (iBAT) as well as tail temperature, suggesting increased heat production in the iBAT and heat dissipation over the tail surface. Finally, nesfatin-1 upregulated pro-opiomelanocortin and melanocortin 3 receptor mRNA expression in the hypothalamus, accompanied by a significant increase in iodothyronine deiodinase 2 and by a nonsignificant increase in uncoupling protein 1 and peroxisome proliferator-activated receptor gamma coactivator-1 alpha mRNA in the iBAT. Overall, we clearly demonstrate that nesfatin-1 requires the activation of the central melanocortin system to increase iBAT thermogenesis and, in turn, overall energy expenditure.
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Affiliation(s)
- Riccardo Dore
- Department of Internal Medicine ICenter of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Luka Levata
- Department of Internal Medicine ICenter of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Sogol Gachkar
- Department of Internal Medicine ICenter of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Olaf Jöhren
- Center of BrainBehavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Jens Mittag
- Department of Internal Medicine ICenter of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Hendrik Lehnert
- Department of Internal Medicine ICenter of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Carla Schulz
- Department of Internal Medicine ICenter of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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4
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Iemolo A, Seiglie M, Blasio A, Cottone P, Sabino V. Pituitary adenylate cyclase-activating polypeptide (PACAP) in the central nucleus of the amygdala induces anxiety via melanocortin receptors. Psychopharmacology (Berl) 2016; 233:3269-77. [PMID: 27376948 PMCID: PMC4982769 DOI: 10.1007/s00213-016-4366-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 06/18/2016] [Indexed: 11/29/2022]
Abstract
RATIONALE Anxiety disorders are the most common mental disorders in the USA. Characterized by feelings of uncontrollable apprehension, they are accompanied by physical, affective, and behavioral symptoms. The neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptor PAC1 (PAC1R) are highly expressed in the central nucleus of the amygdala (CeA), and they have gained growing attention for their proposed role in mediating the body's response to stress. OBJECTIVES The aim of this study was to evaluate the anxiogenic effects of PACAP in the CeA and its effects on the hypothalamic-pituitary-adrenal (HPA) axis. Furthermore, the mechanism of action of PACAP in the CeA was investigated. METHODS PACAP was microinfused into the CeA of rats, and its effects in the elevated plus maze (EPM), the defensive withdrawal tests, and plasma corticosterone levels were evaluated. The ability of the melanocortin receptor antagonist SHU9119 to block PACAP effect in the EPM was assessed. RESULTS Intra-CeA PACAP exerted a dose-dependent anxiogenic effect and activated the HPA axis. In contrast, PACAP microinfused into the basolateral nucleus of the amygdala (BlA) had no effect. Finally, the anxiogenic effect of intra-CeA PACAP was prevented by SHU9119. CONCLUSIONS These data prove an anxiogenic role for the PACAP system of the CeA and reveal that the melanocortin receptor 4 (MC4R) system of CeA mediates these effects. Our data provide insights into this neuropeptide system as a mechanism for modulating the behavioral and endocrine response to stress and suggest that dysregulations of this system may contribute to the pathophysiology of anxiety-related disorders.
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Affiliation(s)
- Attilio Iemolo
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, 72 E Concord St, R-612, Boston, MA, 02118, USA
| | - Mariel Seiglie
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, 72 E Concord St, R-612, Boston, MA, 02118, USA
- Graduate Program in Neuroscience, Boston University, Boston, MA, USA
| | - Angelo Blasio
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, 72 E Concord St, R-612, Boston, MA, 02118, USA
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, 72 E Concord St, R-612, Boston, MA, 02118, USA
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, 72 E Concord St, R-612, Boston, MA, 02118, USA.
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5
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Chhabra KH, Adams JM, Fagel B, Lam DD, Qi N, Rubinstein M, Low MJ. Hypothalamic POMC Deficiency Improves Glucose Tolerance Despite Insulin Resistance by Increasing Glycosuria. Diabetes 2016; 65:660-72. [PMID: 26467632 PMCID: PMC4764146 DOI: 10.2337/db15-0804] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 10/07/2015] [Indexed: 12/18/2022]
Abstract
Hypothalamic proopiomelanocortin (POMC) is essential for the physiological regulation of energy balance; however, its role in glucose homeostasis remains less clear. We show that hypothalamic arcuate nucleus (Arc)POMC-deficient mice, which develop severe obesity and insulin resistance, unexpectedly exhibit improved glucose tolerance and remain protected from hyperglycemia. To explain these paradoxical phenotypes, we hypothesized that an insulin-independent pathway is responsible for the enhanced glucose tolerance. Indeed, the mutant mice demonstrated increased glucose effectiveness and exaggerated glycosuria relative to wild-type littermate controls at comparable blood glucose concentrations. Central administration of the melanocortin receptor agonist melanotan II in mutant mice reversed alterations in glucose tolerance and glycosuria, whereas, conversely, administration of the antagonist Agouti-related peptide (Agrp) to wild-type mice enhanced glucose tolerance. The glycosuria of ArcPOMC-deficient mice was due to decreased levels of renal GLUT 2 (rGLUT2) but not sodium-glucose cotransporter 2 and was associated with reduced renal catecholamine content. Epinephrine treatment abolished the genotype differences in glucose tolerance and rGLUT2 levels, suggesting that reduced renal sympathetic nervous system (SNS) activity is the underlying mechanism for the observed glycosuria and improved glucose tolerance in ArcPOMC-deficient mice. Therefore, the ArcPOMC-SNS-rGLUT2 axis is potentially an insulin-independent therapeutic target to control diabetes.
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Affiliation(s)
- Kavaljit H Chhabra
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Jessica M Adams
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI
| | - Brian Fagel
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Daniel D Lam
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Nathan Qi
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Marcelo Rubinstein
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, and Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Malcolm J Low
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
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6
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Shukla C, Koch LG, Britton SL, Cai M, Hruby VJ, Bednarek M, Novak CM. Contribution of regional brain melanocortin receptor subtypes to elevated activity energy expenditure in lean, active rats. Neuroscience 2015; 310:252-67. [PMID: 26404873 DOI: 10.1016/j.neuroscience.2015.09.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 09/10/2015] [Accepted: 09/11/2015] [Indexed: 12/13/2022]
Abstract
Physical activity and non-exercise activity thermogenesis (NEAT) are crucial factors accounting for individual differences in body weight, interacting with genetic predisposition. In the brain, a number of neuroendocrine intermediates regulate food intake and energy expenditure (EE); this includes the brain melanocortin (MC) system, consisting of MC peptides as well as their receptors (MCR). MC3R and MC4R have emerged as critical modulators of EE and food intake. To determine how variance in MC signaling may underlie individual differences in physical activity levels, we examined behavioral response to MC receptor agonists and antagonists in rats that show high and low levels of physical activity and NEAT, that is, high- and low-capacity runners (HCR, LCR), developed by artificial selection for differential intrinsic aerobic running capacity. Focusing on the hypothalamus, we identified brain region-specific elevations in expression of MCR 3, 4, and also MC5R, in the highly active, lean HCR relative to the less active and obesity-prone LCR. Further, the differences in activity and associated EE as a result of MCR activation or suppression using specific agonists and antagonists were similarly region-specific and directly corresponded to the differential MCR expression patterns. The agonists and antagonists investigated here did not significantly impact food intake at the doses used, suggesting that the differential pattern of receptor expression may by more meaningful to physical activity than to other aspects of energy balance regulation. Thus, MCR-mediated physical activity may be a key neural mechanism in distinguishing the lean phenotype and a target for enhancing physical activity and NEAT.
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Affiliation(s)
- C Shukla
- Department of Biological Sciences, Kent State University, Kent, OH, United States; Harvard Medical School - VA Boston Healthcare System, Boston, MA, United States.
| | - L G Koch
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States; Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - S L Britton
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States; Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - M Cai
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States
| | - V J Hruby
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States
| | - M Bednarek
- MedImmune Limited, Cambridge, United Kingdom
| | - C M Novak
- Department of Biological Sciences, Kent State University, Kent, OH, United States
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7
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Simamura E, Arikawa T, Ikeda T, Shimada H, Shoji H, Masuta H, Nakajima Y, Otani H, Yonekura H, Hatta T. Melanocortins contribute to sequential differentiation and enucleation of human erythroblasts via melanocortin receptors 1, 2 and 5. PLoS One 2015; 10:e0123232. [PMID: 25860801 PMCID: PMC4393082 DOI: 10.1371/journal.pone.0123232] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 02/17/2015] [Indexed: 11/30/2022] Open
Abstract
In this study, we showed that adrenocorticotropic hormone (ACTH) promoted erythroblast differentiation and increased the enucleation ratio of erythroblasts. Because ACTH was contained in hematopoietic medium as contamination, the ratio decreased by the addition of anti-ACTH antibody (Ab). Addition of neutralizing Abs (nAbs) for melanocortin receptors (MCRs) caused erythroblast accumulation at specific stages, i.e., the addition of anti-MC2R nAb led to erythroblast accumulation at the basophilic stage (baso-E), the addition of anti-MC1R nAb caused accumulation at the polychromatic stage (poly-E), and the addition of anti-MC5R nAb caused accumulation at the orthochromatic stage (ortho-E). During erythroblast differentiation, ERK, STAT5, and AKT were consecutively phosphorylated by erythropoietin (EPO). ERK, STAT5, and AKT phosphorylation was inhibited by blocking MC2R, MC1R, and MC5R, respectively. Finally, the phosphorylation of myosin light chain 2, which is essential for the formation of contractile actomyosin rings, was inhibited by anti-MC5R nAb. Taken together, our study suggests that MC2R and MC1R signals are consecutively required for the regulation of EPO signal transduction in erythroblast differentiation, and that MC5R signal transduction is required to induce enucleation. Thus, melanocortin induces proliferation and differentiation at baso-E, and polarization and formation of an actomyosin contractile ring at ortho-E are required for enucleation.
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MESH Headings
- Adrenocorticotropic Hormone/antagonists & inhibitors
- Adrenocorticotropic Hormone/metabolism
- Antibodies, Neutralizing
- Cell Differentiation/physiology
- Cells, Cultured
- Erythroblasts/cytology
- Erythroblasts/metabolism
- Erythropoiesis/physiology
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Humans
- Melanocortins/metabolism
- Models, Biological
- Proto-Oncogene Proteins c-akt/metabolism
- Receptor, Melanocortin, Type 1/antagonists & inhibitors
- Receptor, Melanocortin, Type 1/genetics
- Receptor, Melanocortin, Type 1/metabolism
- Receptor, Melanocortin, Type 2/antagonists & inhibitors
- Receptor, Melanocortin, Type 2/genetics
- Receptor, Melanocortin, Type 2/metabolism
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Melanocortin/genetics
- Receptors, Melanocortin/metabolism
- STAT5 Transcription Factor/metabolism
- Signal Transduction
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Affiliation(s)
- Eriko Simamura
- Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Tomohiro Arikawa
- Department of Biology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Takayuki Ikeda
- Department of Biochemistry, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Hiroki Shimada
- Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Hiroki Shoji
- Department of Biology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Hiroko Masuta
- Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Yuriko Nakajima
- Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Hiroki Otani
- Department of Developmental Biology, Faculty of Medicine, Shimane University, Izumo 693–8601, Japan
| | - Hideto Yonekura
- Department of Biochemistry, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
| | - Toshihisa Hatta
- Department of Anatomy, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920–0293, Japan
- * E-mail:
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8
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Derkach KV, Kuznetsova LA, Sharova TS, Ignatieva PA, Bondareva VM, Shpakov AO. [THE EFFECTS OF LONG-TERM METFORMIN TREATMENT ON THE ACTIVITY OF ADENYLYL CYCLASE SYSTEM AND NO-SYNTHASES IN THE BRAIN AND THE MYOCARDIUM OF RATS WITH OBESITY]. Tsitologiia 2015; 57:360-369. [PMID: 26281213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Biguanide metformin, which is widely used for the treatment of type 2 diabetes mellitus, improves carbohydrate and lipid metabolism and shows a pronounced cardio- and neuroprotective effects. It is assumed that an important role in these effects of metformin plays its ability to positively influence the activity of NO-synthase catalyzing the synthesis of NO, the most important vasodilator, and the activity of hormone-sensitive adenylyl cyclase signaling system (ACSS. To prove this, we have carried out a study whose purpose was to study the effect of long-term metformin treatment on the metabolic rates in obese rats, as well as on the activity of ACSS and NO-synthase in the myocardium and the brain of these animals. The metformin treatment of Wistar rats with obesity induced by high-fat diet was carried out for 2 months (daily dose of 200 mg/kg). The treatment with metformin led to a decrease in body weight and body fat, reduced glucose and insulin levels as well as reduced insulin resistance index HOMA-IR, improved glucose tolerance, and decreased the level of atherogenic forms of cholesterol. In the myocardium of obese rats, the attenuation of ACSS stimulation induced by the agonists of β1/β2-adrenergic receptors (AR) and the strengthening of β3-AR signaling has been found. At the same time, in the myocardium of animals treated with metformin, the regulation of ACSS by adrenergic agonists was restored, and the ratio of β-AR-signaling pathways returned to normal. In the brain of rats treated with metformin, adenylyl cyclase stimulating effects of serotonin and agonists of type 4 melanocortin receptors, which had been weakenend for obesity, were restored. Metformin treatment completely restored activity of total and endothelial NO-synthase in the myocardium decreased in obesity. It as also shown that metformin treatment induced hyperactivation of NO-synthase in the myocardium and brain of healthy animals. Thus, we conclude that the effects of metformin identified by us in rats with long-term treatment of obesity may explain cardio- and neuroprotective influence of this drug.
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9
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Cortés R, Navarro S, Agulleiro MJ, Guillot R, García-Herranz V, Sánchez E, Cerdá-Reverter JM. Evolution of the melanocortin system. Gen Comp Endocrinol 2014; 209:3-10. [PMID: 24768673 DOI: 10.1016/j.ygcen.2014.04.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 04/01/2014] [Accepted: 04/03/2014] [Indexed: 11/17/2022]
Abstract
The melanocortin system is one of the most complex of the hormonal systems. It involves different agonists encoded in the multiplex precursor proopiomelanocortin (POMC) or in different genes as β-defensins, endogenous antagonist, like agouti-signalling protein (ASIP) or agouti-related protein (AGRP), and five different melanocortin receptors (MCRs). Rounds of whole genome duplication events have preceded the functional and molecular diversification of the family in addition some co-evolutionary and tandem duplication processes have been proposed. The evolutionary patterns of the different partners are controversial and different hypotheses have emerged from a study of the sequenced genomes. In this review, we summarize the different evolutionary hypotheses proposed for the different melanocortin partners.
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Affiliation(s)
- Raúl Cortés
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain
| | - Sandra Navarro
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain
| | - Maria Josep Agulleiro
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain
| | - Raúl Guillot
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain
| | - Víctor García-Herranz
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain
| | - Elisa Sánchez
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain
| | - José Miguel Cerdá-Reverter
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain.
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10
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Meek TH, Matsen ME, Damian V, Cubelo A, Chua SC, Morton GJ. Role of melanocortin signaling in neuroendocrine and metabolic actions of leptin in male rats with uncontrolled diabetes. Endocrinology 2014; 155:4157-67. [PMID: 25137027 PMCID: PMC4197991 DOI: 10.1210/en.2014-1169] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although the antidiabetic effects of leptin require intact neuronal melanocortin signaling in rodents with uncontrolled diabetes (uDM), increased melanocortin signaling is not sufficient to mimic leptin's glucose-lowering effects. The current studies were undertaken to clarify the role of melanocortin signaling in leptin's ability to correct metabolic and neuroendocrine disturbances associated with uDM. To accomplish this, bilateral cannulae were implanted in the lateral ventricle of rats with streptozotocin-induced diabetes, and leptin was coinfused with varying doses of the melanocortin 3/4 receptor (MC3/4R) antagonist, SHU9119. An additional cohort of streptozotocin-induced diabetes rats received intracerebroventricular administration of either the MC3/4R agonist, melanotan-II, or its vehicle. Consistent with previous findings, leptin's glucose-lowering effects were blocked by intracerebroventricular SHU9119. In contrast, leptin-mediated suppression of hyperglucagonemia involves both melanocortin dependent and independent mechanisms, and the degree of glucagon inhibition was associated with reduced plasma ketone body levels. Increased central nervous system melanocortin signaling alone fails to mimic leptin's ability to correct any of the metabolic or neuroendocrine disturbances associated with uDM. Moreover, the inability of increased melanocortin signaling to lower diabetic hyperglycemia does not appear to be secondary to release of the endogenous MC3/4R inverse agonist, Agouti-related peptide (AgRP), because AgRP knockout mice did not show increased susceptibility to the antidiabetic effects of increased MC3/4R signaling. Overall, these data suggest that 1) AgRP is not a major driver of diabetic hyperglycemia, 2) mechanisms independent of melanocortin signaling contribute to leptin's antidiabetic effects, and 3) melanocortin receptor blockade dissociates leptin's glucose-lowering effect from its action on other features of uDM, including reversal of hyperglucagonemia and ketosis, suggesting that brain control of ketosis, but not blood glucose levels, is glucagon dependent.
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Affiliation(s)
- Thomas H Meek
- Diabetes and Obesity Center of Excellence (T.H.M., M.E.M.,. V.D., A.C., G.J.M.), Department of Medicine, University of Washington, Seattle, Washington 98109; and Division of Endocrinology (S.C.C.), Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461
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11
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Abstract
Aminoprocalcitonin (N-PCT), a neuroendocrine peptide encoded by the calcitonin-I (CALC-I) gene, suppresses food intake when administered centrally in rats. However, the neural pathways underlying this effect remain unclear. N-PCT and calcitonin receptors (CT-R) have been identified in hypothalamic regions involved in energy homeostasis, including the arcuate nucleus (ARC). Here, we hypothesized an involvement of the hypothalamic ARC in mediating the anorexic effects of central N-PCT based on its content of peptidergic neurons involved in feeding and its expression of N-PCT and CT-R. Fasting strongly reduced expression of the N-PCT precursor gene CALC-I in the ARC, and central immunoneutralization of endogenous N-PCT increased food intake. Intracerebroventricular administration of N-PCT reduced food intake in fed and fasted rats, and its effect was attenuated by a neutralizing anti-N-PCT antibody. Immunohistochemistry for N-PCT showed that it is expressed in astrocytes and neurons in the ARC and is colocalized with anorexigenic proopiomelanocortin (POMC) neurons. Fasting reduced coexpression of N-PCT and POMC, and N-PCT administration activated hypothalamic neurons, including rostral POMC neurons. We also found that N-PCT stimulates POMC mRNA expression in fed and fasted rats, whereas it reduced the expression of orexigenic peptides neuropeptide Y (NPY) and agouti-related peptide (AgRP) only in fasted rats in which those mRNAs are normally elevated. Finally, we showed that the melanocortin-3/4 receptor antagonist SHU 9119 attenuates the intake-suppressive effect of N-PCT. These data demonstrate that hypothalamic N-PCT is involved in control of energy balance and that its anorexigenic effects are mediated through the melanocortin system.
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MESH Headings
- Agouti-Related Protein/genetics
- Agouti-Related Protein/metabolism
- Animals
- Anorexia/metabolism
- Anorexia/physiopathology
- Antibodies, Neutralizing/pharmacology
- Arcuate Nucleus of Hypothalamus/physiology
- Calcitonin/genetics
- Calcitonin/immunology
- Calcitonin/metabolism
- Calcitonin Gene-Related Peptide
- Eating/physiology
- Energy Metabolism/physiology
- Feeding Behavior/physiology
- Male
- Melanocyte-Stimulating Hormones/pharmacology
- Neuropeptide Y/genetics
- Neuropeptide Y/metabolism
- Protein Precursors/genetics
- Protein Precursors/immunology
- Protein Precursors/metabolism
- Rats
- Rats, Wistar
- Receptor, Melanocortin, Type 3
- Receptor, Melanocortin, Type 4/antagonists & inhibitors
- Receptor, Melanocortin, Type 4/metabolism
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Melanocortin/metabolism
- Signal Transduction/physiology
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Affiliation(s)
- Eva Tavares
- Unidad de Farmacología Experimental y Clínica, Hospital Universitario de Valme, Seville, Spain; and
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12
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Yamada-Goto N, Katsuura G, Ebihara K, Inuzuka M, Ochi Y, Yamashita Y, Kusakabe T, Yasoda A, Satoh-Asahara N, Ariyasu H, Hosoda K, Nakao K. Intracerebroventricular administration of C-type natriuretic peptide suppresses food intake via activation of the melanocortin system in mice. Diabetes 2013; 62:1500-4. [PMID: 23274904 PMCID: PMC3636603 DOI: 10.2337/db12-0718] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
C-type natriuretic peptide (CNP) and its receptor are abundantly distributed in the brain, especially in the arcuate nucleus (ARC) of the hypothalamus associated with regulating energy homeostasis. To elucidate the possible involvement of CNP in energy regulation, we examined the effects of intracerebroventricular administration of CNP on food intake in mice. The intracerebroventricular administration of CNP-22 and CNP-53 significantly suppressed food intake on 4-h refeeding after 48-h fasting. Next, intracerebroventricular administration of CNP-22 and CNP-53 significantly decreased nocturnal food intake. The increment of food intake induced by neuropeptide Y and ghrelin was markedly suppressed by intracerebroventricular administration of CNP-22 and CNP-53. When SHU9119, an antagonist for melanocortin-3 and melanocortin-4 receptors, was coadministered with CNP-53, the suppressive effect of CNP-53 on refeeding after 48-h fasting was significantly attenuated by SHU9119. Immunohistochemical analysis revealed that intracerebroventricular administration of CNP-53 markedly increased the number of c-Fos-positive cells in the ARC, paraventricular nucleus, dorsomedial hypothalamus, ventromedial hypothalamic nucleus, and lateral hypothalamus. In particular, c-Fos-positive cells in the ARC after intracerebroventricular administration of CNP-53 were coexpressed with α-melanocyte-stimulating hormone immunoreactivity. These results indicated that intracerebroventricular administration of CNP induces an anorexigenic action, in part, via activation of the melanocortin system.
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Affiliation(s)
- Nobuko Yamada-Goto
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan.
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13
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Singh A, Dirain M, Witek R, Rocca JR, Edison AS, Haskell-Luevano C. Structure-activity relationships of peptides incorporating a bioactive reverse-turn heterocycle at the melanocortin receptors: identification of a 5800-fold mouse melanocortin-3 receptor (mMC3R) selective antagonist/partial agonist versus the mouse melanocortin-4 receptor (mMC4R). J Med Chem 2013; 56:2747-63. [PMID: 23432160 PMCID: PMC3652311 DOI: 10.1021/jm301253y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The melanocortin-3 (MC3) and melanocortin-4 (MC4) receptors regulate energy homeostasis, food intake, and associated physiological conditions. The melanocortin-4 receptor (MC4R) has been studied extensively. Less is known about specific physiological roles of the melanocortin-3 receptor (MC3R). A major obstacle to this lack of knowledge is attributed to a limited number of identified MC3R selective ligands. We previously reported a spatial scanning approach of a 10-membered thioether-heterocycle ring incorporated into a chimeric peptide template that identified a lead nM MC4R ligand. Upon the basis of those results, 17 compounds were designed and synthesized that focused upon modification in the pharmacophore domain. Notable results include the identification of a 0.13 nM potent 5800-fold mMC3R selective antagonist/slight partial agonist versus a 760 nM mMC4R full agonist (ligand 11). Biophysical experiments (two-dimensional (1)H NMR and computer-assisted molecular modeling) of this ligand resulted in the identification of an inverse γ-turn secondary structure in the ligand pharmacophore domain.
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Affiliation(s)
- Anamika Singh
- Departments of Medicinal Chemistry and Pharmacodynamics University of Florida, Gainesville, FL 32610, USA
- Department of Medicinal Chemistry University of Minnesota, Minneapolis, MN 55455, USA
| | - Marvin Dirain
- Departments of Medicinal Chemistry and Pharmacodynamics University of Florida, Gainesville, FL 32610, USA
| | - Rachel Witek
- Departments of Medicinal Chemistry and Pharmacodynamics University of Florida, Gainesville, FL 32610, USA
| | - James R. Rocca
- McKnight Brain Institute, University of Florida, Gainesville, FL 32611
| | - Arthur S Edison
- Department of Biochemistry & Molecular Biology and National High Magnetic Field Laboratory, University of Florida, Gainesville, FL 32610, USA
| | - Carrie Haskell-Luevano
- Departments of Medicinal Chemistry and Pharmacodynamics University of Florida, Gainesville, FL 32610, USA
- Department of Medicinal Chemistry University of Minnesota, Minneapolis, MN 55455, USA
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14
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Lanfray D, Arthaud S, Ouellet J, Compère V, Do Rego JL, Leprince J, Lefranc B, Castel H, Bouchard C, Monge-Roffarello B, Richard D, Pelletier G, Vaudry H, Tonon MC, Morin F. Gliotransmission and brain glucose sensing: critical role of endozepines. Diabetes 2013; 62:801-10. [PMID: 23160530 PMCID: PMC3581199 DOI: 10.2337/db11-0785] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hypothalamic glucose sensing is involved in the control of feeding behavior and peripheral glucose homeostasis, and glial cells are suggested to play an important role in this process. Diazepam-binding inhibitor (DBI) and its processing product the octadecaneuropeptide (ODN), collectively named endozepines, are secreted by astroglia, and ODN is a potent anorexigenic factor. Therefore, we investigated the involvement of endozepines in brain glucose sensing. First, we showed that intracerebroventricular administration of glucose in rats increases DBI expression in hypothalamic glial-like tanycytes. We then demonstrated that glucose stimulates endozepine secretion from hypothalamic explants. Feeding experiments indicate that the anorexigenic effect of central administration of glucose was blunted by coinjection of an ODN antagonist. Conversely, the hyperphagic response elicited by central glucoprivation was suppressed by an ODN agonist. The anorexigenic effects of centrally injected glucose or ODN agonist were suppressed by blockade of the melanocortin-3/4 receptors, suggesting that glucose sensing involves endozepinergic control of the melanocortin pathway. Finally, we found that brain endozepines modulate blood glucose levels, suggesting their involvement in a feedback loop controlling whole-body glucose homeostasis. Collectively, these data indicate that endozepines are a critical relay in brain glucose sensing and potentially new targets in treatment of metabolic disorders.
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Affiliation(s)
- Damien Lanfray
- INSERM U982, DC2N Laboratory of Neuronal and Neuroendocrine Cell Differentiation and Communication, Mont-Saint-Aignan, France
- Institute for Biomedical Research and Innovation, Regional Platform for Cell Imaging (PRIMACEN), Rouen, France
- University of Rouen, Mont-Saint-Aignan, France
| | - Sébastien Arthaud
- Institute for Biomedical Research and Innovation, Regional Platform for Cell Imaging (PRIMACEN), Rouen, France
- University of Rouen, Mont-Saint-Aignan, France
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 5167, University Claude Bernard Lyon 1, Lyon, France
| | - Johanne Ouellet
- Research Center in Molecular Endocrinology, Oncology and Human Genomics, Laval University, Quebec, Quebec, Canada
| | - Vincent Compère
- INSERM U982, DC2N Laboratory of Neuronal and Neuroendocrine Cell Differentiation and Communication, Mont-Saint-Aignan, France
- Institute for Biomedical Research and Innovation, Regional Platform for Cell Imaging (PRIMACEN), Rouen, France
- University of Rouen, Mont-Saint-Aignan, France
- Department of Anaesthesiology and Critical Care, Rouen University Hospital, Rouen, France
| | - Jean-Luc Do Rego
- INSERM U982, DC2N Laboratory of Neuronal and Neuroendocrine Cell Differentiation and Communication, Mont-Saint-Aignan, France
- Institute for Biomedical Research and Innovation, Regional Platform for Cell Imaging (PRIMACEN), Rouen, France
- University of Rouen, Mont-Saint-Aignan, France
| | - Jérôme Leprince
- INSERM U982, DC2N Laboratory of Neuronal and Neuroendocrine Cell Differentiation and Communication, Mont-Saint-Aignan, France
- Institute for Biomedical Research and Innovation, Regional Platform for Cell Imaging (PRIMACEN), Rouen, France
- University of Rouen, Mont-Saint-Aignan, France
| | - Benjamin Lefranc
- Institute for Biomedical Research and Innovation, Regional Platform for Cell Imaging (PRIMACEN), Rouen, France
- University of Rouen, Mont-Saint-Aignan, France
| | - Hélène Castel
- INSERM U982, DC2N Laboratory of Neuronal and Neuroendocrine Cell Differentiation and Communication, Mont-Saint-Aignan, France
- Institute for Biomedical Research and Innovation, Regional Platform for Cell Imaging (PRIMACEN), Rouen, France
- University of Rouen, Mont-Saint-Aignan, France
| | - Cynthia Bouchard
- Centre de Recherche de l’Institut Universitaire de Cardiologie et Pneumologie de Québec, Laval University, Quebec, Quebec, Canada
| | - Boris Monge-Roffarello
- Centre de Recherche de l’Institut Universitaire de Cardiologie et Pneumologie de Québec, Laval University, Quebec, Quebec, Canada
| | - Denis Richard
- Centre de Recherche de l’Institut Universitaire de Cardiologie et Pneumologie de Québec, Laval University, Quebec, Quebec, Canada
| | - Georges Pelletier
- Research Center in Molecular Endocrinology, Oncology and Human Genomics, Laval University, Quebec, Quebec, Canada
| | - Hubert Vaudry
- INSERM U982, DC2N Laboratory of Neuronal and Neuroendocrine Cell Differentiation and Communication, Mont-Saint-Aignan, France
- Institute for Biomedical Research and Innovation, Regional Platform for Cell Imaging (PRIMACEN), Rouen, France
- University of Rouen, Mont-Saint-Aignan, France
- Research Center in Molecular Endocrinology, Oncology and Human Genomics, Laval University, Quebec, Quebec, Canada
| | - Marie-Christine Tonon
- INSERM U982, DC2N Laboratory of Neuronal and Neuroendocrine Cell Differentiation and Communication, Mont-Saint-Aignan, France
- Institute for Biomedical Research and Innovation, Regional Platform for Cell Imaging (PRIMACEN), Rouen, France
- University of Rouen, Mont-Saint-Aignan, France
- Corresponding author: Marie-Christine Tonon, , or Fabrice Morin,
| | - Fabrice Morin
- INSERM U982, DC2N Laboratory of Neuronal and Neuroendocrine Cell Differentiation and Communication, Mont-Saint-Aignan, France
- Institute for Biomedical Research and Innovation, Regional Platform for Cell Imaging (PRIMACEN), Rouen, France
- University of Rouen, Mont-Saint-Aignan, France
- Corresponding author: Marie-Christine Tonon, , or Fabrice Morin,
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15
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Vaughan CH, Shrestha YB, Bartness TJ. Characterization of a novel melanocortin receptor-containing node in the SNS outflow circuitry to brown adipose tissue involved in thermogenesis. Brain Res 2011; 1411:17-27. [PMID: 21802070 DOI: 10.1016/j.brainres.2011.07.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 07/01/2011] [Indexed: 11/19/2022]
Abstract
The melanocortins (MC) can affect interscapular brown adipose tissue (IBAT) thermogenesis via its sympathetic nervous system (SNS) innervation. We chose a site of high MC4-receptor (MC4-R) mRNA co-localization with SNS outflow neurons to IBAT, the subzona incerta (subZI) to test whether IBAT thermogenesis could be increased or decreased. We first performed immunohistochemical characterization of the subZI and found neurons and/or fibers in this area positive for melanin concentrating hormone, oxytocin, arginine vasopressin, agouti-related protein and alpha-melanocyte stimulating hormone. Functional characterization of the subZI was tested via site-specific microinjections. The MC3/4-R agonist, melanotan II [MTII (0.025, 0.05 and 0.075nmol)], and specific MC4-R agonist (cyclo [ß-Ala-His-D-Phe-Arg-Trp-Glu]-NH2; 0.024nmol) both significantly increased IBAT temperature (T(IBAT)) and pretreatment with the MC4R antagonist, HS024 (0.072nmol) blocked the MC4-R agonist-induced increased T(IBAT) in conscious, freely-moving Siberian hamsters. Injection of the MC4-R antagonist alone significantly decreased T(IBAT) up to 3h post injection. Collectively, these results highlight the identification of a brain area that possesses high concentrations of MC4-R mRNA and SNS outflow neurons to IBAT that has not been previously reported to be involved in the control of T(IBAT). These results add to previously identified neural nodes that are components of the central circuits controlling thermogenesis.
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MESH Headings
- Adipose Tissue, Brown/innervation
- Adipose Tissue, Brown/physiology
- Animals
- Arginine Vasopressin/pharmacology
- Cricetinae
- Dose-Response Relationship, Drug
- Immunohistochemistry
- Male
- Microinjections
- Phenotype
- Phodopus
- Receptor, Melanocortin, Type 4/agonists
- Receptor, Melanocortin, Type 4/antagonists & inhibitors
- Receptors, Melanocortin/agonists
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Melanocortin/physiology
- Stereotaxic Techniques
- Sympathetic Nervous System/metabolism
- Telemetry
- Thermogenesis/physiology
- Vasoconstrictor Agents/pharmacology
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Affiliation(s)
- C H Vaughan
- Department of Biology, Center for Obesity Reversal, Georgia State University,Atlanta, GA, 30302-4010, USA
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16
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Hruby VJ, Cai M, Cain J, Nyberg J, Trivedi D. Design of novel melanocortin receptor ligands: multiple receptors, complex pharmacology, the challenge. Eur J Pharmacol 2011; 660:88-93. [PMID: 21208601 PMCID: PMC3138524 DOI: 10.1016/j.ejphar.2010.10.109] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 10/05/2010] [Accepted: 10/16/2010] [Indexed: 11/22/2022]
Abstract
The major pharmacophore for the melanocortin 1, 3, 4 and 5 receptors is the sequence -His-Phe-Arg-Trp-. There is a need for potent, biologically stable, receptor selective ligands, both agonists and antagonists, for these receptors. In this report we briefly examine the structural and biophysical approaches we have taken to develop selective agonist and antagonist ligands that can cross (or not) the blood brain barrier. Remaining questions and unmet needs are also discussed.
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Affiliation(s)
- Victor J Hruby
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA.
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17
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Lee CJ, Yun JH, Lim SK, Lee W. Solution structures and molecular interactions of selective melanocortin receptor antagonists. Mol Cells 2010; 30:551-6. [PMID: 21110130 DOI: 10.1007/s10059-010-0152-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 09/11/2010] [Accepted: 09/13/2010] [Indexed: 10/18/2022] Open
Abstract
The solution structures and inter-molecular interaction of the cyclic melanocortin antagonists SHU9119, JKC363, HS014, and HS024 with receptor molecules have been determined by NMR spectroscopy and molecular modeling. While SHU9119 is known as a nonselective antagonist, JKC363, HS014, and HS024 are selective for the melanocortin subtype-4 receptor (MC4R) involved in modulation of food intake. Data from NMR and molecular dynamics suggest that the conformation of the Trp9 sidechain in the three MC4R-selective antagonists is quite different from that of SHU9119. This result strongly supports the concept that the spatial orientation of the hydrophobic aromatic residue is more important for determining selectivity than the presence of a basic, "arginine-like" moiety responsible for biological activity. We propose that the conformation of hydrophobic residues of MCR antagonists is critical for receptor-specific selectivity.
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MESH Headings
- Amino Acid Sequence
- Binding Sites
- Drug Interactions
- Hydrophobic and Hydrophilic Interactions
- Magnetic Resonance Spectroscopy
- Melanocyte-Stimulating Hormones/chemical synthesis
- Melanocyte-Stimulating Hormones/chemistry
- Melanocyte-Stimulating Hormones/pharmacology
- Models, Molecular
- Molecular Sequence Data
- Peptides, Cyclic/chemical synthesis
- Peptides, Cyclic/chemistry
- Peptides, Cyclic/pharmacology
- Receptor, Melanocortin, Type 4/antagonists & inhibitors
- Receptor, Melanocortin, Type 4/drug effects
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Melanocortin/drug effects
- Sensitivity and Specificity
- Solutions/chemistry
- Structure-Activity Relationship
- beta-MSH/chemical synthesis
- beta-MSH/chemistry
- beta-MSH/pharmacology
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Affiliation(s)
- Chul-Jin Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
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18
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Tanaka M, Suganami T, Sugita S, Shimoda Y, Kasahara M, Aoe S, Takeya M, Takeda S, Kamei Y, Ogawa Y. Role of central leptin signaling in renal macrophage infiltration. Endocr J 2010; 57:61-72. [PMID: 19851035 DOI: 10.1507/endocrj.k09e-296] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Monocytes/macrophages are key mediators of wound repair, tissue remodeling, and inflammation. However, the molecular mechanisms underlying macrophage recruitment to the site of inflammation is not fully understood. Leptin acts directly on the hypothalamus, thereby regulating food intake and energy expenditure. The leptin receptor, a single transmembrane protein that belongs to the gp130 family of cytokine receptor superfamily, is expressed not only in the hypothalamus but in a variety of peripheral tissues, suggesting the role of leptin as a pro-inflammatory adipocytokine in peripheral tissues. Here, we show that deficiency of leptin signaling reduces renal macrophage infiltration after unilateral ureteral obstruction (UUO). Bone marrow transplantation studies using leptin signaling-deficient db/db mice revealed that leptin signaling in bone marrow cells may not play a major role in the UUO-induced renal macrophage infiltration. Interestingly, central leptin administration reverses the otherwise reduced UUO-induced renal macrophage infiltration in leptin-deficient ob/ob mice. This is effectively abolished by central co-administration of SHU9119, a melanocortin-3 receptor/melanocortin-4 receptor antagonist. This study demonstrates that central leptin administration in ob/ ob mice accelerates renal macrophage infiltration through the melanocortin system, thereby suggesting that the central nervous system, which is inherent to integrate information from throughout the organism, is able to control peripheral inflammation.
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Affiliation(s)
- Miyako Tanaka
- Department of Molecular Medicine and Metabolism, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
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19
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Toda C, Shiuchi T, Lee S, Yamato-Esaki M, Fujino Y, Suzuki A, Okamoto S, Minokoshi Y. Distinct effects of leptin and a melanocortin receptor agonist injected into medial hypothalamic nuclei on glucose uptake in peripheral tissues. Diabetes 2009; 58:2757-65. [PMID: 19752162 PMCID: PMC2780865 DOI: 10.2337/db09-0638] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVE The medial hypothalamus mediates leptin-induced glucose uptake in peripheral tissues, and brain melanocortin receptors (MCRs) mediate certain central effects of leptin. However, the contributions of the leptin receptor and MCRs in individual medial hypothalamic nuclei to regulation of peripheral glucose uptake have remained unclear. We examined the effects of an injection of leptin and the MCR agonist MT-II into medial hypothalamic nuclei on glucose uptake in peripheral tissues. RESEARCH DESIGN AND METHODS Leptin or MT-II was injected into the ventromedial (VMH), dorsomedial (DMH), arcuate nucleus (ARC), or paraventricular (PVH) hypothalamus or the lateral ventricle (intracerebroventricularly) in freely moving mice. The MCR antagonist SHU9119 was injected intracerebroventricularly. Glucose uptake was measured by the 2-[(3)H]deoxy-d-glucose method. RESULTS Leptin injection into the VMH increased glucose uptake in skeletal muscle, brown adipose tissue (BAT), and heart, whereas that into the ARC increased glucose uptake in BAT, and that into the DMH or PVH had no effect. SHU9119 abolished these effects of leptin injected into the VMH. Injection of MT-II either into the VMH or intracerebroventricularly increased glucose uptake in skeletal muscle, BAT, and heart, whereas that into the PVH increased glucose uptake in BAT, and that into the DMH or ARC had no effect. CONCLUSIONS The VMH mediates leptin- and MT-II-induced glucose uptake in skeletal muscle, BAT, and heart. These effects of leptin are dependent on MCR activation. The leptin receptor in the ARC and MCR in the PVH regulate glucose uptake in BAT. Medial hypothalamic nuclei thus play distinct roles in leptin- and MT-II-induced glucose uptake in peripheral tissues.
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Affiliation(s)
- Chitoku Toda
- Department of Physiological Sciences, Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa, Japan
- Division of Endocrinology and Metabolism, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Tetsuya Shiuchi
- Department of Physiological Sciences, Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa, Japan
- Division of Endocrinology and Metabolism, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Suni Lee
- Division of Endocrinology and Metabolism, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Maya Yamato-Esaki
- Department of Physiological Sciences, Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa, Japan
- Division of Endocrinology and Metabolism, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Yusuke Fujino
- Division of Endocrinology and Metabolism, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
- Department of Internal Medicine 1, Faculty of Medicine, Oita University, Hasama, Oita, Japan
| | - Atsushi Suzuki
- Division of Endocrinology and Metabolism, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Shiki Okamoto
- Department of Physiological Sciences, Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa, Japan
- Division of Endocrinology and Metabolism, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Yasuhiko Minokoshi
- Department of Physiological Sciences, Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa, Japan
- Division of Endocrinology and Metabolism, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
- Corresponding author: Yasuhiko Minokoshi,
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20
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Abstract
Of the central nervous system receptors that could mediate the energy balance effects of leptin, those of the hypothalamic arcuate nucleus receive the greatest attention. Melanocortin receptors (MC-Rs) contribute to the feeding and energetic effects of hypothalamically delivered leptin. Energy balance effects of leptin are also mediated by extrahypothalamic neurons including the hindbrain nucleus tractus solitarius. Hindbrain leptin receptors play a role in leptin's anorectic effects, but their contribution to its energetic effects and their functional interaction with melanocortin systems within the hindbrain remains unexplored. Here rats implanted with telemetric devices for recording energetic/cardiovascular responses were examined to determine whether: 1) hindbrain (fourth ventricular) leptin receptor stimulation triggers energetic and cardiovascular effects, 2) these effects are altered by a 6-wk high-fat diet maintenance, and 3) hindbrain MC-Rs mediate the thermogenic, cardiovascular, and anorexic effects of hindbrain leptin delivery. Results show that hindbrain leptin receptor stimulation produced long-lasting (>6 h) increases in core temperature and heart rate and also decreased food intake and body weight. These responses were not altered by high-fat maintenance, in contrast to what has been reported for forebrain leptin delivery. Fourth ventricular pretreatment with MC-R antagonist SHU 9119 completely abolished the hyperthermia, anorexia, and body weight loss seen with hindbrain-directed leptin but had no effects of its own. These data highlight a role for hindbrain leptin receptors in the initiation of energetic and anorexic responses and show that MCRs are part of the downstream mediation of hindbrain leptin-induced energy balance effects, paralleling effects observed for hypothalamic leptin receptors.
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Affiliation(s)
- Karolina P Skibicka
- Graduate Group of Psychology and Graduate Group of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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21
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Schjolden J, Schiöth HB, Larhammar D, Winberg S, Larson ET. Melanocortin peptides affect the motivation to feed in rainbow trout (Oncorhynchus mykiss). Gen Comp Endocrinol 2009; 160:134-8. [PMID: 19027741 DOI: 10.1016/j.ygcen.2008.11.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Revised: 10/16/2008] [Accepted: 11/01/2008] [Indexed: 11/29/2022]
Abstract
In this study, we investigated the effects of one melanocortin receptor (MCR) agonist and two antagonists on food intake in juvenile rainbow trout. Baseline food intake was established prior to 1 microl intracerebroventricular injection (ICV) of the non-specific agonist MTII, the MC4R antagonist HS024 and the MC3/4R antagonist SHU9119 at concentrations of 0.3, 1 or 3 nM. Saline-injected fish and untreated fish served as controls. Changes in food intake were observed 1h after the ICV injections. Our results showed that treatment with MTII significantly decreased food intake at 3 nM compared to control, HS024 significantly increased food intake at 3 nM compared to control and saline-treated fish, and SHU9119 significantly increased food intake at 3 nM compared to saline-treated fish. In conclusion, our study provides further evidence, and hence strengthens the hypothesis, that MC4R participates in the control of energy balance in fish in the same manner as in mammals. Our findings that HS024 is more potent than SHU9119 in increasing food intake suggest that the effects of melanocortin on energy balance in rainbow trout are mainly regulated by activation of MC4R. Hence, HS024 seems an excellent tool as a MC4R antagonist in rainbow trout.
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Affiliation(s)
- Joachim Schjolden
- Department of Basic Sciences and Aquatic Medicine, Norwegian School of Veterinary Science, P.O. Box 8146 Dep, Ullevålsveien 72, N-0033 Oslo, Norway.
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22
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Abstract
OBJECTIVE Xenin, a 25-amino acid peptide, was initially isolated from human gastric mucosa. Plasma levels of xenin rise after a meal in humans, and administration of xenin inhibits feeding in rats and chicks. However, little is known about the mechanism by which xenin regulates food intake. Signaling pathways including leptin and melanocortins play a pivotal role in the regulation of energy balance. Therefore, we addressed the hypothesis that xenin functions as a satiety factor by acting through the melanocortin system or by interacting with leptin. RESEARCH DESIGN AND METHODS The effect of intracerebroventricular and intraperitoneal administration of xenin on food intake was examined in wild-type, agouti, and ob/ob mice. The effect of intracerebroventricular injection of SHU9119, a melanocortin receptor antagonist, on xenin-induced anorexia was also examined in wild-type mice. To determine whether the hypothalamus mediates the anorectic effect of xenin, we examined the effect of intraperitoneal xenin on hypothalamic Fos expression. RESULTS Both intracerebroventricular and intraperitoneal administration of xenin inhibited fasting-induced hyperphagia in wild-type mice in a dose-dependent manner. The intraperitoneal injection of xenin also reduced nocturnal intake in ad libitum-fed wild-type mice. The intraperitoneal injection of xenin increased Fos immunoreactivity in hypothalamic nuclei, including the paraventricular nucleus and the arcuate nucleus. Xenin reduced food intake in agouti and ob/ob mice. SHU9119 did not block xenin-induced anorexia. CONCLUSIONS Our data suggest that xenin reduces food intake partly by acting through the hypothalamus but via signaling pathways that are independent of those used by leptin or melanocortins.
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Affiliation(s)
- Arnold Leckstrom
- Department of Physiology, University of Manitoba, Winnipeg, Manitoba, Canada
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23
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Abstract
PURPOSE OF REVIEW Cachexia is a condition of anorexia and wasting that accompanies many diseases including cancer, heart failure, and renal failure. One key center that is probably involved in the propagation of symptoms of cachexia is the melanocortin system in the hypothalamus and brainstem. This review focuses on cachexia treatment interventions that act via melanocortin antagonism, by direct or indirect means. RECENT FINDINGS Recent reports include a description of the physiology of the melanocortin system and its responsiveness to inflammatory cytokines. Regarding treatment potential, multiple reports describe the effectiveness of small molecule antagonists of the melanocortin-4 receptor in animal models of cachexia. These melanocortin antagonists, given by peripheral injection, improve food intake and lean body mass retention in the setting of cancer and renal failure. Additional reports provide evidence of melanocortin antagonism following treatment of cachexia using ghrelin and eicosonoic acid. SUMMARY Cachexia is a serious condition that accompanies various disease states and currently does not have effective treatments. The melanocortin system may play a direct role in producing symptoms of cachexia, making antagonism of this system a logical objective for ameliorating these symptoms. Thus far, however, no data on human application have been published.
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Affiliation(s)
- Mark D DeBoer
- Division of Endocrinology, University of Virginia, Charlottesville, Virginia 22908, USA.
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24
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Grieco P, Cai M, Han G, Trivedi D, Campiglia P, Novellino E, Hruby VJ. Further structure-activity studies of lactam derivatives of MT-II and SHU-9119: their activity and selectivity at human melanocortin receptors 3, 4, and 5. Peptides 2007; 28:1191-6. [PMID: 17482720 PMCID: PMC1955225 DOI: 10.1016/j.peptides.2007.02.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 02/23/2007] [Indexed: 10/23/2022]
Abstract
Recently we have demonstrated that replacing His(6) by constrained amino acids(2) in the well-known antagonist SHU-9119 resulted in potent and selective antagonist ligands especially at the hMC3R and hMC5 receptors. With the aim to further explore position 6 in the sequence of SHU-9119 and MT-II, we have designed, synthesized, and pharmacologically characterized a series of peptide analogues of MT-II and SHU-9119 at the human melanocortin receptors subtypes MC3R, MC4R and MC5R. All these peptides were modified at position 6 with constrained amino acids which are commercially available. In this study, we have identified new selective ligands for the hMC4R, and an antagonist for the hMC3/hMC4 receptors. Additionally, we have discovered an interesting new selective antagonist at the hMC3R, Ac-Nle-c[Asp-betaAla-DNal(2')-Arg-Trp-Lys]-NH(2) (2, PG-106) which represents an important tool in further biological investigations of the hMC3R. PG-106 will be useful in further efforts to differentiate the substructural features responsible for selectivity at the hMC3R, hMC4R, and hMC5R.
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MESH Headings
- Humans
- Lactams/chemistry
- Lactams/pharmacology
- Melanocyte-Stimulating Hormones/chemical synthesis
- Melanocyte-Stimulating Hormones/chemistry
- Melanocyte-Stimulating Hormones/pharmacology
- Molecular Structure
- Peptides, Cyclic/chemical synthesis
- Peptides, Cyclic/chemistry
- Peptides, Cyclic/pharmacology
- Receptor, Melanocortin, Type 3/antagonists & inhibitors
- Receptor, Melanocortin, Type 3/drug effects
- Receptor, Melanocortin, Type 4/antagonists & inhibitors
- Receptor, Melanocortin, Type 4/drug effects
- Receptors, Corticotropin/antagonists & inhibitors
- Receptors, Corticotropin/drug effects
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Melanocortin/drug effects
- Structure-Activity Relationship
- alpha-MSH/analogs & derivatives
- alpha-MSH/chemical synthesis
- alpha-MSH/chemistry
- alpha-MSH/pharmacology
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Affiliation(s)
- Paolo Grieco
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, USA
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25
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Joppa MA, Gogas KR, Foster AC, Markison S. Central infusion of the melanocortin receptor antagonist agouti-related peptide (AgRP(83-132)) prevents cachexia-related symptoms induced by radiation and colon-26 tumors in mice. Peptides 2007; 28:636-42. [PMID: 17204351 DOI: 10.1016/j.peptides.2006.11.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Revised: 11/28/2006] [Accepted: 11/29/2006] [Indexed: 01/08/2023]
Abstract
Cachexia is a clinical wasting syndrome that occurs in multiple disease states, and is associated with anorexia and a progressive loss of body fat and lean mass. The development of new therapeutics for this disorder is needed due to poor efficacy and multiple side effects of current therapies. The pivotal role played by the central melanocortin system in regulating body weight has made this an attractive target for novel cachexia therapies. The mixed melanocortin receptor antagonist AgRP is an endogenous peptide that induces hyperphagia. Here, we used AgRP(83-132) to investigate the ability of melanocortin antagonism to protect against clinical features of cachexia in two distinct animal models. In an acute model, food intake and body weight gain were reduced in mice exposed to radiation (300 RAD), and delivery of AgRP(83-132) into the lateral cerebral ventricle prevented these effects. In a chronic tumor cachexia model, adult mice were injected subcutaneously with a cell line derived from murine colon-26 adenocarcinoma. Typical of cachexia, tumor-bearing mice progressively reduced body weight and food intake, and gained significantly less muscle mass than controls. Administration of AgRP(83-132) into the lateral ventricles significantly increased body weight and food intake, and changes in muscle mass were similar to the tumor-free control mice. These findings support the idea that antagonism of the central melanocortin system can reduce the negative impact of cachexia and radiation therapy.
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Affiliation(s)
- M A Joppa
- Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, CA 92130, USA
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26
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King SH, Mayorov AV, Balse-Srinivasan P, Hruby VJ, Vanderah TW, Wessells H. Melanocortin receptors, melanotropic peptides and penile erection. Curr Top Med Chem 2007; 7:1098-1106. [PMID: 17584130 PMCID: PMC2694735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Penile erection is a complex physiologic event resulting from the interactions of the nervous system on a highly specialized vascular organ. Activation of central nervous system melanocortinergic (MC) receptors with either endogenous or synthetic melanotropic ligands may initiate and/or facilitate spontaneous penile erection. While the CNS contains principally the MC3 and MC4 receptor subtypes, there is conflicting data as to which receptor mediates erection. Although the MC4R is emerging as the principle effector of MC induced erection, the role of the MC3R is poorly understood. Manipulation of each receptor subtype with newly synthesized receptor specific agonists and antagonists, as well as knockout mice, has elucidated their individual contributions. Novel data from our laboratories suggests that antagonism of forebrain MC3R may enhance melanocortin-induced erections. Furthermore, melanocortin agents may interact with better-studied systems such as oxytocinergic pathways at the hypothalamic, brainstem or spinal level. Current therapies for erectile dysfunction target end organ vascular tissue. Manipulation of MC receptors may provide an alternative, centrally mediated therapeutic approach for erectile and other sexual dysfunctions. The non-specific "superpotent" MC agonist, PT-141, which is the carboxylate derivative of MT-II, has reached phase II human trials. Through their centrally mediated activity, melanocortin agonists have potential to treat erectile dysfunction as well as possible applications to the unmet medical needs of decreased sexual motivation and loss of libido.
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Affiliation(s)
| | | | | | | | | | - Hunter Wessells
- Address correspondence to this author at the Department of Urology, University of Washington, Harborview Medical Center, 325 Ninth Avenue, Seattle Washington 98104; Tel: 206-731-3205; Fax: 206-731-4709; E-mail:
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27
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Abstract
The melanocortin system is composed of the melanocortin peptides, adrenocorticotropic hormone and alpha-, beta-, and gamma-melanocyte-stimulating hormone, the melanocortin receptors (MCRs), and the endogenous antagonists agouti- and agouti-related protein. Melanocortin peptides exert multiple effects upon the host, including anti-inflammatory and immunomodulatory effects. Leukocytes are a source of melanocortins and a major target for these peptides. Because of reduced translocation of the nuclear factor NF-kappaB to the nucleus, MCR activation by their ligands causes a collective reduction of the most important molecules involved in the inflammatory process. This review examines how melanocortin peptides and their receptors participate in leukocyte biology.
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Affiliation(s)
- Anna Catania
- Center for Preclinical Investigation, Padiglione Granelli, Fondazione IRCCS Ospedale Maggiore Policlinico Mangiagalli e Regina Elena, Via F Sforza 35, Milano, Italy.
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28
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Cai M, Varga EV, Stankova M, Mayorov A, Perry JW, Yamamura HI, Trivedi D, Hruby VJ. Cell signaling and trafficking of human melanocortin receptors in real time using two-photon fluorescence and confocal laser microscopy: differentiation of agonists and antagonists. Chem Biol Drug Des 2006; 68:183-93. [PMID: 17105482 PMCID: PMC2547351 DOI: 10.1111/j.1747-0285.2006.00432.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Melanocortin hormones and neurotransmitters regulate a vast array of physiologic processes by interacting with five G-protein-coupled melanocortin receptor types. In the present study, we have systematically studied the regulation of individual human melanocortin receptor wild subtypes using a synthetic rhodamine-labeled human melanotropin agonist and antagonist, arrestins fused to green fluorescent protein in conjunction with two-photon fluorescence laser scanning microscopy and confocal microscopy. Stimulation of the melanocortin receptors by its cognate agonist triggered rapid arrestin recruitment and receptor internalization for all four human melanocortin receptors examined. Antagonists-bound melanocortin receptors, on the other hand, did not recruit beta-arrestins, and remained in the cell membrane even after long-term (30 min) treatment. Agonist-mediated internalization of all melanocortin receptor subtypes was sensitive to inhibitors of clathrin-dependent endocytosis, but not to caveolae inhibitors. In summary, agonist-mediated internalization of all subtypes of melanocortin receptors are dependent upon beta-arrestin-mediated clathrin-coated pits, whereas, beta-arrestin-2 conjugated green fluorescence protein (beta-arrestin-2-GFP) recruitment is not dependent on protein kinase A activation. Real time two-photon fluorescence laser scanning microscopy is a most powerful tool to study the dynamic processes in living cells and tissues, without inflicting significant and often lethal damage to the specimen.
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Affiliation(s)
- Minying Cai
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Eva V. Varga
- Department of Pharmacology, University of Arizona, Tucson, AZ 85721, USA
| | - Magda Stankova
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Alexander Mayorov
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Joseph W. Perry
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, USA
- Department of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Henry I. Yamamura
- Department of Pharmacology, University of Arizona, Tucson, AZ 85721, USA
| | - Dev Trivedi
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Victor J. Hruby
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, USA
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29
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Heisler LK, Jobst EE, Sutton GM, Zhou L, Borok E, Thornton-Jones Z, Liu HY, Zigman JM, Balthasar N, Kishi T, Lee CE, Aschkenasi CJ, Zhang CY, Yu J, Boss O, Mountjoy KG, Clifton PG, Lowell BB, Friedman JM, Horvath T, Butler AA, Elmquist JK, Cowley MA. Serotonin reciprocally regulates melanocortin neurons to modulate food intake. Neuron 2006; 51:239-49. [PMID: 16846858 DOI: 10.1016/j.neuron.2006.06.004] [Citation(s) in RCA: 287] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 02/03/2006] [Accepted: 06/06/2006] [Indexed: 12/18/2022]
Abstract
The neural pathways through which central serotonergic systems regulate food intake and body weight remain to be fully elucidated. We report that serotonin, via action at serotonin1B receptors (5-HT1BRs), modulates the endogenous release of both agonists and antagonists of the melanocortin receptors, which are a core component of the central circuitry controlling body weight homeostasis. We also show that serotonin-induced hypophagia requires downstream activation of melanocortin 4, but not melanocortin 3, receptors. These results identify a primary mechanism underlying the serotonergic regulation of energy balance and provide an example of a centrally derived signal that reciprocally regulates melanocortin receptor agonists and antagonists in a similar manner to peripheral adiposity signals.
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MESH Headings
- Animals
- Eating/drug effects
- Eating/physiology
- Electric Stimulation
- Male
- Mice
- Mice, Inbred A
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Obese
- Mice, Transgenic
- Nerve Net/drug effects
- Nerve Net/physiology
- Neurons/drug effects
- Neurons/physiology
- Pyridines/pharmacology
- Receptor, Melanocortin, Type 3/physiology
- Receptor, Melanocortin, Type 4/agonists
- Receptor, Melanocortin, Type 4/antagonists & inhibitors
- Receptor, Melanocortin, Type 4/physiology
- Receptor, Serotonin, 5-HT1B/physiology
- Receptors, Melanocortin/agonists
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Melanocortin/physiology
- Serotonin/pharmacology
- Serotonin/physiology
- Serotonin 5-HT1 Receptor Agonists
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Affiliation(s)
- Lora K Heisler
- Department of Clinical Biochemistry, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 2QQ, United Kingdom.
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30
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Hillebrand JJG, Kas MJH, Scheurink AJW, van Dijk G, Adan RAH. AgRP(83-132) and SHU9119 differently affect activity-based anorexia. Eur Neuropsychopharmacol 2006; 16:403-12. [PMID: 16360312 DOI: 10.1016/j.euroneuro.2005.11.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Revised: 10/26/2005] [Accepted: 11/04/2005] [Indexed: 12/22/2022]
Abstract
Activity-based anorexia (ABA) mimics starvation and hyperactivity of anorexia nervosa patients in rats. Activation of the melanocortin (MC) system leads to hypophagia and increased energy expenditure in ad libitum fed rats. Therefore, activation of the MC system might underlie the development and propagation of ABA. Pro-opiomelanocortin (POMC) gene expression is normally decreased during negative energy balance. Strikingly, we found a transient up-regulation of POMC mRNA levels in the arcuate nucleus during the development of ABA, indicating a hyperactive MC system. However, wheel running and food intake were not influenced by treating ABA rats with the competitive antagonist SHU9119. This suggests that agonism of MC receptors by endogenous alpha-melanocyte-stimulating hormone (alpha-MSH) levels does not underlie ABA. Instead, treatment with the inverse agonist AgRP(83-132) did ameliorate signs of ABA. This implies that modulation of constitutive MC receptor activity rather than antagonizing putative alpha-MSH release contributes to the development and propagation of ABA.
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Affiliation(s)
- Jacquelien J G Hillebrand
- Department of Pharmacology and Anatomy, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
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31
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Abstract
It is well established that disruptions in melanocortin signaling in the CNS result in morbid obesity, but only recently has evidence linked the activation of this system with the production of cachexia, also known as disease-associated wasting. Pro-opiomelanocortin-producing neurons, which express cytokine receptors, show increased activation in the presence of several cytokines that are increased in diseases that are associated with cachexia. Recent experiments show that blockade of melanocortin signaling using antagonists to the melanocortin MC(4) receptor attenuates disease-associated anorexia and wasting in rodent models of cancer and renal failure. This successful inhibition of cachexia is important because loss of appetite and lean body mass worsen the prognosis of many the diseases with which cachexia is associated.
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Affiliation(s)
- Mark D Deboer
- Department of Pediatrics, Oregon Health and Science University, 707 SW Gaines Rd., Portland, Oregon 97239, USA.
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32
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Abstract
Agouti signaling protein (ASIP) is an endogenous antagonist of melanocortin receptors that controls a wide range of physiological functions. Its central role in regulation of the melanocortin system implied that ASIP has been relevant to the evolution of various physiological traits in primates. In this study, we have tried to determine DNA sequences of the ASIP gene (ASIP) of various simian species to find molecular evolutionary aspects of ASIP. Unexpectedly, we found that the whole coding region of ASIP was missing only from the gibbon genome; gibbons constitute a large group of hominoid species in Southeast Asia. Our analyses revealed that unequal homologous recombination mediated by two AluSx elements erased a approximately 100-kb region including ASIP from the gibbon genome. The data provide new evidence for the significant roles of Alu elements in the dynamic evolution of the primate genome.
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Affiliation(s)
- Kazuhiro Nakayama
- Unit of Human Biology and Genetics, Department of Biological Sciences, Graduate School of Science and Center for Evolutionary Cognitive Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Takafumi Ishida
- Unit of Human Biology and Genetics, Department of Biological Sciences, Graduate School of Science and Center for Evolutionary Cognitive Sciences, The University of Tokyo, Tokyo 113-0033, Japan
- Corresponding author.E-mail ; fax +81 3-3818-7547
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33
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Wilson KR, Todorovic A, Proneth B, Haskell-Luevano C. Overview of endogenous and synthetic melanocortin peptides. Cell Mol Biol (Noisy-le-grand) 2006; 52:3-20. [PMID: 16914082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2000] [Accepted: 03/28/2000] [Indexed: 05/11/2023]
Abstract
The melanocortin system consists of five seven-transmembrane spanning G-protein coupled (GPCRs) receptors (MC1R-MC5R), the endogenous agonists a-, B- and melanocyte stimulating hormone (MSH), adrenocorticotropic hormone (ACTH), and the endogenous antagonists Agouti and Agouti-related protein (AGRP). Melanocortin agonists are involved in the regulation of feeding behavior and weight omeostasis in mammals. Structure-activity relationships (SAR) have been performed on the endogenous melanocortin receptor agonists and antagonists that have identified ligand amino acid residues implicated as important for receptor binding and stimulation. Knowledge of putative ligand-receptor interactions may help to design molecules as therapeutic agents for the treatment of physiological diseases.
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Affiliation(s)
- K R Wilson
- Department of Medicinal Chemistry, University of Florida, 1600 SW Archer Road PO Box 100485, Gainesville, FL 32610, USA
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34
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Abstract
Adrenocorticotrophic hormone (ACTH(1-39)) and the melanocortins (alpha, beta and gamma-melanocyte-stimulating hormone [MSH]) are derived from a larger precursor molecule known as the pro-opiomelanocortin (POMC) protein. They exert their numerous biological effects by activating 7 transmembrane G-protein coupled receptors (GPCR), leading to adenylyl cyclase activation and subsequent cAMP accumulation within the target cell. To date, 5 melanocortin receptors (MCR) have been identified and termed MC1R to MC5R, they have been shown to have a wide and varied distribution throughout the body, being found in the central nervous system (CNS), periphery and immune cells. Melanocortins have a multitude of actions including: (i) modulating disease pathologies including arthritis, asthma, obesity; (ii) affecting functions, for example erectile dysfunction, skin tanning; and (iii) organ systems, for example cardiovascular system. Recently a mechanistic approach has been identified with alpha-MSH preventing NF-kappaB activation via the preservation and expression of IkappaBalphaprotein. This leads to a reduction of pro-inflammatory mediators including cytokines and inhibition of adhesion molecule expression, with subsequent reduction in leukocyte emigration. Development of selective ligands with an appropriate pharmacokinetic profile will enable a pharmacological evaluation of the potential beneficial effects of the melanocortins. In this review I have discussed the potential mechanistic action for the melanocortins and some of the disease pathologies shown to be modulated. This review proposes targeting the MCR with the ultimate aim of controlling many of the diseases that we face today.
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Affiliation(s)
- Stephen J Getting
- The William Harvey Research Institute, Charterhouse Square, London, EC1M 6BQ, United Kingdom.
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35
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Cabeza de Vaca S, Hao J, Afroz T, Krahne LL, Carr KD. Feeding, body weight, and sensitivity to non-ingestive reward stimuli during and after 12-day continuous central infusions of melanocortin receptor ligands. Peptides 2005; 26:2314-21. [PMID: 15894406 DOI: 10.1016/j.peptides.2005.03.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Revised: 03/21/2005] [Accepted: 03/22/2005] [Indexed: 10/25/2022]
Abstract
The brain melanocortin system mediates downstream effects of hypothalamic leptin and insulin signaling. Yet, there have been few studies of chronic intracerebroventricular (i.c.v.) melanocortin receptor (MCR) agonist or antagonist infusion. Although there is evidence of interaction between melanocortin and dopamine (DA) systems, effects of chronic MCR ligand infusion on behavioral sensitivity to non-ingestive reward stimuli have not been investigated. The objective of this study was to investigate effects of chronic i.c.v. infusion of the MCR agonist, MTII, and the MCR antagonist, SHU9119, on food intake, body weight, and sensitivity to rewarding lateral hypothalamic electrical stimulation (LHSS) and the reward-potentiating (i.e., threshold-lowering) effect of D-amphetamine. The MCR antagonist, SHU9119 (0.02 microg/h) produced sustained hyperphagia and weight gain during the 12-day infusion period, followed by compensatory hypophagia and an arrest of body weight gain during the 24-day post-infusion period. At no point during the experiment was sensitivity to LHSS or D-amphetamine (0.25mg/kg, i.p.) altered. The MCR agonist, MTII (0.02 microg/h) produced a brief hypophagia (3 days) followed by a return to control levels of daily intake, but with body weight remaining at a reduced level throughout the 12-day infusion period. This was followed by compensatory hyperphagia and weight gain during the 24-day post-infusion period. There was no change in sensitivity to non-ingestive reward stimuli during the infusion of MTII. However, sensitivity to D-amphetamine was increased during the 24-day post-infusion period. It therefore seems that changes in ingestive behavior that occur during chronic MCR ligand infusion may not affect the response to non-ingestive reward stimuli. However, it is possible that the drive to re-feed and restore body weight following MCR agonist treatment includes neuroadaptations that enhance the incentive effects of drug stimuli.
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Affiliation(s)
- S Cabeza de Vaca
- Department of Psychiatry, New York University School of Medicine, Millhauser Laboratories, 550 First Avenue, New York, NY 10016, USA.
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36
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Fisher MJ, Backer RT, Collado I, de Frutos O, Husain S, Hsiung HM, Kuklish SL, Mateo AI, Mullaney JT, Ornstein PL, Paredes CG, O'Brian TP, Richardson TI, Shah J, Zgombick JM, Briner K. Privileged structure based ligands for melanocortin receptors—Substituted benzylic piperazine derivatives. Bioorg Med Chem Lett 2005; 15:4973-8. [PMID: 16169215 DOI: 10.1016/j.bmcl.2005.08.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Revised: 08/03/2005] [Accepted: 08/03/2005] [Indexed: 11/22/2022]
Abstract
Replacement of the aryl piperazine moiety in compound 1 with a variety of substituted benzylic piperazines (6) yields compounds that afford melanocortin receptor 4 (MCR4) activity. Analogs with ortho substitution on the aromatic ring afforded the highest affinity. Resolution of the stereocenter of the benzylic piperazine based privileged structure revealed that the R-enantiomer was more active.
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Affiliation(s)
- Matthew J Fisher
- Lilly Research Laboratories, A Division of Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46258, USA.
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37
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Starowicz K, Obara I, Przewłocki R, Przewlocka B. Inhibition of morphine tolerance by spinal melanocortin receptor blockade. Pain 2005; 117:401-411. [PMID: 16153779 DOI: 10.1016/j.pain.2005.07.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2004] [Revised: 06/14/2005] [Accepted: 07/12/2005] [Indexed: 11/26/2022]
Abstract
Chronic use of morphine is accompanied by the development of morphine tolerance, which is one of the major problems associated with opiate treatment. Possible modulation of opioid effects by melanocortin receptor ligands has been recently demonstrated. Therefore, we investigated the influence of repeated intrathecal injection of a melanocortin receptor antagonist (SHU9119, JKC-363) on the development of morphine tolerance as measured by tail-flick test. It was also examined whether a single i.t. SHU9119 and JKC-363 administration could counteract the loss of analgesic potency of morphine in morphine tolerant rats. We examined also the influence of chronic morphine administration on mu-opioid receptor (MOR) and melanocortin 4 receptor (MC4-R) mRNAs in the rat spinal cord and dorsal root ganglia (DRG) during morphine tolerance. Morphine treatment (10mg/kg, i.p. twice daily) over 8 days induced tolerance as reflected by a significant reduction of withdrawal latency from 181 to 25% above baseline in the tail-flick test. Repeated co-administration of morphine and SHU9119 or JKC-363, significantly prevented the development of morphine tolerance. A single administration of an MC4-R antagonist restored morphine analgesic potency in morphine tolerant rats. Using RT-PCR we demonstrated no changes in the spinal cord but there was a decrease in MOR and increase in MC4-R gene expression in the DRG of rats tolerant to morphine. These results suggest that MC4-R may be involved in the mechanisms of opioid tolerance and antagonists of this receptor may be a possible new target in the search for strategies preventing the development of opioid tolerance.
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MESH Headings
- Analysis of Variance
- Animals
- Area Under Curve
- Behavior, Animal
- Dose-Response Relationship, Drug
- Drug Administration Schedule
- Drug Interactions
- Drug Tolerance/physiology
- Gene Expression Regulation/drug effects
- Male
- Melanocyte-Stimulating Hormones/pharmacology
- Morphine/adverse effects
- Pain Measurement/drug effects
- Pain Measurement/instrumentation
- Peptides, Cyclic/pharmacology
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Reaction Time/drug effects
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Spinal Cord/drug effects
- Spinal Cord/metabolism
- Time Factors
- beta-MSH/pharmacology
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Affiliation(s)
- Katarzyna Starowicz
- Department of Molecular Neuropharmacology, Institute of Pharmacology, 12 Smetna str, 31-343 Cracow, Poland Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, 4 Ks. Trojdena str, 02-109 Warsaw, Poland
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38
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Abstract
The process of energy homeostasis is a highly regulated process involving interacting signals between a variety of anorexigenic and orexigenic peptides, proteins and signaling molecules. The melanocortin system is an important component of this complex regulatory network. Involvement of the melanocortin pathway in the control of food intake and body weight regulation has been studied extensively in the past two decades. Previous studies that involve central administration of melanocortin molecules and examination of molecules that effect food intake in melanocortin knockout (KO) mice (MC3R, MC4R, POMC, AGRP and NPY) have been examined. In this review, we have summarized feeding studies that have resulted in the recognition of the melanocortin system as a major contributor to the complex neuroendocrine system regulating energy homeostasis.
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Affiliation(s)
- Boman G Irani
- Department of Medicinal Chemistry, University of Florida, P.O. Box 100485, Gainesville, FL-32610, USA
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39
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Jackson PJ, Yu B, Hunrichs B, Thompson DA, Chai B, Gantz I, Millhauser GL. Chimeras of the agouti-related protein: insights into agonist and antagonist selectivity of melanocortin receptors. Peptides 2005; 26:1978-87. [PMID: 16009463 DOI: 10.1016/j.peptides.2004.12.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2004] [Accepted: 12/12/2004] [Indexed: 11/29/2022]
Abstract
The specific melanocortin receptors, MC3R and MC4R, are directly linked to metabolism and body weight control. These receptors are activated by the peptide hormone alpha-MSH and antagonized by the agouti-related protein (AGRP). Whereas alpha-MSH acts broadly on most members of the MCR family (with the exception of MC2R), AGRP is highly specific for only MC3R and MC4R. AGRP is a complex ligand of approximately 100 amino acids. Within AGRP, MCR recognition and antagonism is localized to a 34 residue, cysteine-rich domain that adopts an inhibitor cystine knot (ICK) fold. An oxidatively folded peptide corresponding to this domain, referred to as mini-AGRP, exhibits full antagonist function and selectivity for MC3R and MC4R. Here we investigate a series of chimera proteins based on the mini-AGRP scaffold. Amino acid sequences derived from peptide agonists are grafted into the mini-AGRP active loop, implicated in receptor recognition, with the goal of producing ICK based agonists specific for MC3R and MC4R. Several constructs indeed exhibited potent agonist activity; however, with all chimeras, receptor selectivity is significantly altered. Pharmacologic data indicate that the chimeras do not interact with MC receptors through native AGRP like contacts. A model to explain the data suggest that there is only partial overlap of the agonist versus antagonist binding surfaces within MC receptors. Moreover, accessibility to the binding pocket is highly receptor specific with MC3R being the least tolerant of ligand alterations.
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Affiliation(s)
- Pilgrim J Jackson
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
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40
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Abstract
Exposure to stress is associated with susceptibility to disease and one stress mediator, norepinephrine, has been reported to enhance the adherence of enterohemorrhagic Escherichia coli O157:H7 (EHEC) to the colonic mucosa. We tested the hypothesis that adrenocorticotropic hormone (ACTH) and other stress-related hormones may act in a similar fashion. Explants of distal colonic mucosa from young pigs were mounted in Ussing chambers and their luminal aspect was exposed to EHEC strain 700728 for 30-90 min. When added to the contraluminal, but not luminal bathing medium, ACTH increased EHEC adherence within 90 min in a concentration-dependent manner (EC50 = 1.2 nM), but did not alter tissue electrical conductance. ACTH had no effect on the adherence of a pig-adapted non-O157 E. coli strain. The effect of 0.1 microM ACTH on luminal EHEC adherence was prevented in tissues pretreated contraluminally with the type 2 melanocortin receptor antagonist ACTH7-38, the neuronal conduction blocker saxitoxin, or the muscarinic cholinergic antagonist atropine. Moreover, ACTH7-38 decreased EHEC adherence in the absence of ACTH. These results suggest that ACTH acts via melanocortin receptors located on enteric nerves to enhance mucosal adherence of EHEC.
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Affiliation(s)
- Kristin L Schreiber
- Graduate Program in Neuroscience, University of Minnesota, Minnesota 55108-6010, USA
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41
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Matsuyama S, Ohkura S, Sakurai K, Tsukamura H, Maeda KI, Okamura H. Activation of melanocortin receptors accelerates the gonadotropin-releasing hormone pulse generator activity in goats. Neurosci Lett 2005; 383:289-94. [PMID: 15955423 DOI: 10.1016/j.neulet.2005.04.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Revised: 03/15/2005] [Accepted: 04/12/2005] [Indexed: 10/25/2022]
Abstract
The present study aims to elucidate whether the central melanocortin receptors [melanocortin-3 and -4 receptors (MC3/4-R)] are involved in regulating GnRH pulse generator activity in female goats. The GnRH pulse generator activity was electrophysiologically assessed at the intervals of characteristic increases in multiple-unit activity (MUA volleys) in the mediobasal hypothalamus. In ovariectomized goats, all doses (0.02, 0.2 and 2 nmol) of MT II, an MC3/4-R agonist, injected into the lateral ventricle significantly shortened MUA volley intervals. The duration of the period during which MT II accelerated MUA volleys was positively correlated with the dose of MT II injected. The stimulatory effect of MT II on the GnRH pulse generator activity was attenuated in the presence of estrogen. Intracerebroventricular injection of SHU9119, an MC3/4-R antagonist, significantly prolonged MUA volley intervals at 1 nmol. MT II (0.2 nmol)-induced acceleration of MUA volleys was partially blocked by the antagonism of MC3/4-R with pre-administered SHU9119 (1 nmol). The present findings demonstrate that MC3/4-R are involved in maintaining GnRH pulse generator activity in goats.
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Affiliation(s)
- Shuichi Matsuyama
- Laboratory of Neuroendocrinology, National Institute of Agrobiological Sciences, 2 Ikenodai, Tsukuba 305-8602, Japan
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42
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Dridi S, Swennen Q, Decuypere E, Buyse J. Mode of leptin action in chicken hypothalamus. Brain Res 2005; 1047:214-23. [PMID: 15907812 DOI: 10.1016/j.brainres.2005.04.034] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2005] [Revised: 04/07/2005] [Accepted: 04/15/2005] [Indexed: 11/19/2022]
Abstract
While there have been many studies in various species examining the mode of central leptin action on food intake, there is however a paucity of data in birds. We have, therefore, addressed this issue in broiler chickens because this strain was selected for high growth rate, hence high food intake. Continuous infusion of recombinant chicken leptin (8 microg/kg/h) during 6 h at a constant rate of 3 ml/h resulted in a significant reduction (49-57%) of food intake in 3-week-old broiler chickens (P < 0.05). The effect of leptin within the central nervous system (CNS) was mediated via selective hypothalamic neuropeptides. Leptin significantly decreased the expression of its receptor (Ob-R), neuropeptide Y (NPY), orexin (ORX), and orexin receptor (ORXR) (P < 0.05), but not that of agouti-related protein (AgRP) (anabolic/orexigenic effectors) in chicken hypothalamus. However, the catabolic/anorexigenic neuropeptides namely proopiomelanocortin (POMC) and corticotropin-releasing hormone (CRH) mRNA levels remained unchanged after leptin treatment. Despite the absence of leptin effect on AgRP (the antagonist of melanocortin receptor MCR) and POMC (the precursor of alpha-melanocyte stimulating hormone which is a potent agonist for MCR), leptin significantly decreased the expression of MCR-4/5 gene in chicken hypothalamus (P < 0.05) suggesting that leptin acts directly (as ligand) or indirectly (via other ligands) on MCRs to regulate food intake in birds. Additionally, leptin down-regulated the expression of fatty acid synthase (FAS) gene in chicken hypothalamus, indicating an additional pathway of leptin action on food intake such as described for FAS inhibitors. These findings provide new insight into the mechanism of leptin control of food intake in chickens.
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MESH Headings
- Agouti-Related Protein
- Animals
- Blotting, Southern
- Chickens/physiology
- Corticosterone/blood
- Corticotropin-Releasing Hormone/biosynthesis
- Corticotropin-Releasing Hormone/drug effects
- DNA Primers
- Fatty Acid Synthases/biosynthesis
- Fatty Acid Synthases/drug effects
- Feeding Behavior/drug effects
- Feeding Behavior/physiology
- Gene Expression/drug effects
- Hypothalamus/drug effects
- Infusions, Intravenous
- Intercellular Signaling Peptides and Proteins
- Intracellular Signaling Peptides and Proteins/drug effects
- Leptin/administration & dosage
- Leptin/blood
- Neuropeptide Y/biosynthesis
- Neuropeptide Y/drug effects
- Neuropeptides/biosynthesis
- Neuropeptides/drug effects
- Orexin Receptors
- Orexins
- Pro-Opiomelanocortin/biosynthesis
- Pro-Opiomelanocortin/drug effects
- Proteins/drug effects
- RNA, Messenger/analysis
- Receptors, Cell Surface/biosynthesis
- Receptors, Cell Surface/drug effects
- Receptors, G-Protein-Coupled
- Receptors, Leptin
- Receptors, Melanocortin/agonists
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Melanocortin/drug effects
- Receptors, Neuropeptide/biosynthesis
- Receptors, Neuropeptide/drug effects
- Recombinant Proteins/administration & dosage
- Reverse Transcriptase Polymerase Chain Reaction
- Thyroid Hormones/blood
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Affiliation(s)
- Sami Dridi
- Laboratory of Physiology and Immunology of Domestic Animals, KU Leuven, 3001 Heverlee, Belgium.
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43
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Cai M, Mayorov AV, Ying J, Stankova M, Trivedi D, Cabello C, Hruby VJ. Design of novel melanotropin agonists and antagonists with high potency and selectivity for human melanocortin receptors. Peptides 2005; 26:1481-5. [PMID: 15876475 DOI: 10.1016/j.peptides.2005.03.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
alpha-MSH and gamma-MSH are the natural endogenous hormones for the human melanocortin-1, 3, 4 and 5 receptors (hMC1R, hMC3R, hMC4R and hMC5R). These and more potent, stable and prolonged acting analogues such as NDP-alpha-MSH, MT-II and SHU-9119 are not very receptor selective. To develop potent and selective agonist and antagonist ligands for the melanocortin receptors we have used state-of-the-art biophysical studies, computational chemistry, and design of conformational and topographical constraints with novel templates.
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Affiliation(s)
- Minying Cai
- Biochemistry and Molecular Biophysics, University of Arizona, Tucson, AZ 85721, USA
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44
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Yang SC, Shieh KR. Differential effects of melanin concentrating hormone on the central dopaminergic neurons induced by the cocaine- and amphetamine-regulated transcript peptide. J Neurochem 2005; 92:637-46. [PMID: 15659233 DOI: 10.1111/j.1471-4159.2004.02896.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Stimulatory effects of cocaine- and amphetamine-regulated transcript (CART) peptide on central mesolimbic, nigrostriatal and mesocortical dopaminergic (DA) neurons were examined in female Sprague-Dawley rats. We also determined the different blocking effects of melanin concentrating hormone (MCH) on the stimulation by CART peptide in central DA systems. Intracerebroventricular administration of 1 microg CART peptide (55-102) produced increases in 3,4-dihydroxyphenylacetic acid (DOPAC) levels in the nucleus accumbens (NA) at 15 and 45 min, and in the striatum (ST) at 15 min, but not in the medial prefrontal cortex (MPFC). We found that the agonist of alpha-melanocyte stimulating hormone (alpha-MSH), MT II, at 10 microg had a stimulatory effect on the NA and ST DOPAC levels similar to the CART peptide. In contrast, 1 microg MCH and the antagonist of alpha-MSH, HS014, significantly decreased NA and ST DOPAC levels. However, only MCH prevented the stimulatory effect of CART peptide on DOPAC levels in the NA, but not in the ST. These results indicate that the stimulation of CART peptide on central DA neurons is region-specific, and that this effect can be blocked by MCH but not by the antagonist of alpha-MSH.
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Affiliation(s)
- Shu-Chuan Yang
- Department of Nursing, Tzu Chi College of Technology, Hualien 970, Taiwan
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45
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Wilczynski A, Wilson KR, Scott JW, Edison AS, Haskell-Luevano C. Structure-activity relationships of the unique and potent agouti-related protein (AGRP)-melanocortin chimeric Tyr-c[beta-Asp-His-DPhe-Arg-Trp-Asn-Ala-Phe-Dpr]-Tyr-NH2 peptide template. J Med Chem 2005; 48:3060-75. [PMID: 15828845 DOI: 10.1021/jm049010r] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The melanocortin receptor system consists of endogenous agonists, antagonists, G-protein coupled receptors, and auxiliary proteins that are involved in the regulation of complex physiological functions such as energy and weight homeostasis, feeding behavior, inflammation, sexual function, pigmentation, and exocrine gland function. Herein, we report the structure-activity relationship (SAR) of a new chimeric hAGRP-melanocortin agonist peptide template Tyr-c[beta-Asp-His-DPhe-Arg-Trp-Asn-Ala-Phe-Dpr]-Tyr-NH(2) that was characterized using amino acids previously reported in other melanocortin agonist templates. Twenty peptides were examined in this study, and six peptides were selected for (1)H NMR and computer-assisted molecular modeling structural analysis. The most notable results include the identification that modification of the chimeric template at the His position with Pro and Phe resulted in ligands that were nM mouse melanocortin-3 receptor (mMC3R) antagonists and nM mouse melanocortin-4 receptor (mMC4R) agonists. The peptides Tyr-c[beta-Asp-His-DPhe-Ala-Trp-Asn-Ala-Phe-Dpr]-Tyr-NH(2) and Tyr-c[beta-Asp-His-DNal(1')-Arg-Trp-Asn-Ala-Phe-Dpr]-Tyr-NH(2) resulted in 730- and 560-fold, respectively, mMC4R versus mMC3R selective agonists that also possessed nM agonist potency at the mMC1R and mMC5R. Structural studies identified a reverse turn occurring in the His-DPhe-Arg-Trp domain, with subtle differences observed that may account for the differences in melanocortin receptor pharmacology. Specifically, a gamma-turn secondary structure involving the DPhe(4) in the central position of the Tyr-c[beta-Asp-Phe-DPhe-Arg-Trp-Asn-Ala-Phe-Dpr]-Tyr-NH(2) peptide may differentiate the mixed mMC3R antagonist and mMC4R agonist pharmacology.
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MESH Headings
- Agouti-Related Protein
- Animals
- Binding, Competitive
- Cell Line
- Drug Design
- Humans
- Intercellular Signaling Peptides and Proteins
- Magnetic Resonance Spectroscopy
- Mice
- Models, Molecular
- Oligopeptides/chemical synthesis
- Oligopeptides/chemistry
- Oligopeptides/pharmacology
- Peptides, Cyclic/chemical synthesis
- Peptides, Cyclic/chemistry
- Peptides, Cyclic/pharmacology
- Protein Structure, Secondary
- Proteins/chemistry
- Receptor, Melanocortin, Type 3/antagonists & inhibitors
- Receptor, Melanocortin, Type 4/agonists
- Receptors, Melanocortin/agonists
- Receptors, Melanocortin/antagonists & inhibitors
- Structure-Activity Relationship
- alpha-MSH/chemistry
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Affiliation(s)
- Andrzej Wilczynski
- University of Florida, Department of Medicinal Chemistry and Biochemistry, Gainesville, Florida 32610, USA
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46
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Blondet A, Doghman M, Rached M, Durand P, Bégeot M, Naville D. Characterization of cell lines stably expressing human normal or mutated EGFP-tagged MC4R. J Biochem 2005; 135:541-6. [PMID: 15115780 DOI: 10.1093/jb/mvh064] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The melanocortin receptor type 4 (MC4-R) is involved in food intake and represents a potential target for the treatment of some forms of obesity. The fluorescent protein EGFP was fused to the wild-type or mutated coding sequence of the human MC4-R. After transfection in HEK 293, clones stably expressing hMC4-R-EGFP were selected. Wild-type chimeric hMC4-R was well addressed to the cell membrane as demonstrated using confocal microscopy and displayed the same pharmacological characteristics as native hMC4R. NDP-alpha MSH induced a time-dependent internalization of MC4-R that was partially prevented by AgRP. The two mutated chimeric receptors studied here (CTCT-deleted and C271A) showed a high alteration of their response to ligand and were retained inside the cells. In conclusion, we have developed a model of clones stably expressing EGFP-tagged-hMC4-R. This is the only such model available to date and it provides a useful tool to follow the trafficking of MC4-R inside living cells.
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MESH Headings
- Agouti-Related Protein
- Binding, Competitive
- Cell Line
- Cell Membrane/metabolism
- Cyclic AMP/metabolism
- Cytoplasmic Vesicles/metabolism
- Dose-Response Relationship, Drug
- Genetic Vectors/genetics
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Humans
- Microscopy, Fluorescence
- Mutation
- Peptide Fragments/pharmacology
- Polymerase Chain Reaction
- Protein Binding
- Protein Transport/drug effects
- Protein Transport/genetics
- Protein Transport/physiology
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Receptors, Melanocortin/agonists
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Melanocortin/metabolism
- Recombinant Fusion Proteins/agonists
- Recombinant Fusion Proteins/antagonists & inhibitors
- Recombinant Fusion Proteins/metabolism
- Transfection
- alpha-MSH/analogs & derivatives
- alpha-MSH/metabolism
- alpha-MSH/pharmacology
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Affiliation(s)
- Antonine Blondet
- INSERM U418-INRA UMR 1245 and IFR 62, Hôpital Debrousse and Claude Bernard University, Lyon, France
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47
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Hansen MJ, Schiöth HB, Morris MJ. Feeding responses to a melanocortin agonist and antagonist in obesity induced by a palatable high-fat diet. Brain Res 2005; 1039:137-45. [PMID: 15781055 DOI: 10.1016/j.brainres.2005.01.063] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2004] [Revised: 01/18/2005] [Accepted: 01/19/2005] [Indexed: 11/24/2022]
Abstract
Hypothalamic melanocortins are critical for the control of food intake, and alterations in POMC mRNA have been described in genetic models of obesity. However, the time course of changes in brain transmitters over the development of dietary obesity is less clear. Therefore, we examined the effect of diet-induced obesity on hypothalamic alpha-MSH content and feeding responsiveness to synthetic melanocortins. Male Sprague-Dawley rats fed a high-fat cafeteria diet (30% fat) or chow (5% fat) for 4 or 12 weeks were implanted with intracerebroventricular cannulae and feeding responses to the MC3/4R agonist MTII (0.5 nmol) and the selective MC4R antagonist HS014 (0.8 nmol) were determined. MTII had a long-lasting inhibitory effect on food intake. Chronically overfed animals had a significantly exaggerated inhibitory feeding response 15 and 24 h after MTII injection and lost more body weight (15 +/- 3 g) compared to control rats (4 +/- 4 g; P < 0.05). Daytime administration of HS014 significantly increased food intake in all rats to the same extent (P < 0.05). No change in hypothalamic alpha-MSH content was observed after 2 or 12 weeks of high-fat diet. The observation of increased responsiveness to the melanocortin agonist, in the face of a high-fat diet, suggests melanocortin analogues may have potential for the pharmacological treatment of obesity.
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Affiliation(s)
- Michelle J Hansen
- Neuroendocrine Laboratory, Department of Pharmacology, The University of Melbourne, Victoria 3010, Australia
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48
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Wilczynski AM, Joseph CG, Haskell-Luevano C. Current trends in the structure—activity relationship studies of the endogenous agouti-related protein (AGRP) melanocortin receptor antagonist. Med Res Rev 2005; 25:545-56. [PMID: 16044415 DOI: 10.1002/med.20037] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Agouti-related protein (AGRP) is an endogenous antagonist of the melanocortin-3 and -4 (MC3R and MC4) G-protein coupled receptors. The 87-132 amino acid C-terminal domain of hAGRP possesses five disulfide bridges and a well-defined three-dimensional structure that displays full biological activity as compared to the full-length protein. Based on the NMR structure of the C-terminal AGRP(87-132), a novel mini-protein, referred to as "Mini-AGRP" was designed that exhibited receptor binding affinity and antagonism similar to that of the parent hAGRP(87-132) protein. It was demonstrated that this new-engineered protein autonomously folds to the inhibitor cystine knot (ICK) motif. As this AGRP is a novel mammalian protein involved in energy homeostasis and possibly other physiological functions remaining to be identified, structure-function studies are starting to emerge toward the understanding of how this unique protein putatively interacts with the melanocortin receptors with the objective of designing potential therapeutic agents for in vivo physiological studies. This article summarizes the progress to date of AGRP-based structure-activity relationships and putative ligand-receptor interactions.
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Affiliation(s)
- Andrzej M Wilczynski
- Department of Medicinal Chemistry, University of Florida, Gainesville, FL 32610, USA
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49
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Wilczynski A, Wang XS, Bauzo RM, Xiang Z, Shaw AM, Millard WJ, Richards NG, Edison AS, Haskell-Luevano C. Structural characterization and pharmacology of a potent (Cys101-Cys119, Cys110-Cys117) bicyclic agouti-related protein (AGRP) melanocortin receptor antagonist. J Med Chem 2004; 47:5662-73. [PMID: 15509165 DOI: 10.1021/jm049620r] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Agouti-related protein (AGRP) is one of two known naturally occurring antagonists of G-protein coupled receptors. AGRP is synthesized in the brain and is an antagonist of the melanocortin-3 and -4 receptors (MC3R, MC4R). These three proteins are involved in the regulation of energy homeostasis and obesity in both mice and humans. The human AGRP protein is 132 amino acids and contains five disulfide bridges in the C-terminal domain. Previous reports of the NMR structures of hAGRP(87-132) and a truncated 34 amino acid form consisting of four disulfide bridges identified that AGRP contains an inhibitor cystine knot (ICK) structural fold, and that is the first mammalian example. Herein, we report a bicyclic hAGRP analogue that, when compared to hAGRP(87-132), possesses equal binding affinity but is 80-fold less potent at the mouse MC4R. Using NMR, computer assisted molecular modeling (CAMM), and cluster analysis, we have identified five structural families, two of which are highly populated, of this bicyclic hAGRP analogue. Computational docking experiments of this bicyclic hAGRP derivative, using a three-dimensional homology molecular model of the mouse MC4R, identified that three of the five structural families could be docked into the MC4R without problems from steric hindrance. Those three docked mMC4R-bicyclic hAGRP family structures were compared with putative hAGRP(87-132) ligand-receptor interactions previously reported (Wilczynski et al. J. Med. Chem. 2004, 47, 2194) in attempts to identify a "bioactive" conformation of the bicyclic hAGRP peptide and account for the 80-fold decreased ligand potency compared to hAGRP(87-132).
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Affiliation(s)
- Andrzej Wilczynski
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, USA
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50
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Irani BG, Holder JR, Todorovic A, Wilczynski AM, Joseph CG, Wilson KR, Haskell-Luevano C. Progress in the Development of Melanocortin Receptor Selective Ligands. Curr Pharm Des 2004; 10:3443-79. [PMID: 15579046 DOI: 10.2174/1381612043382891] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The melanocortin pathway consists of endogenous agonists, antagonists, G-protein coupled receptors (GPCRs), and auxiliary proteins. This pathway has been identified to participate physiologically in numerous biological pathways including energy homeostasis, pigmentation, sexual function, inflammation, cardiovascular function, adrenal function, sebaceous gland lipid production, just to list a few. During this past decade, a clear link between the melanocortin-4 receptor (MC4R) and obesity, in both mice and humans via the regulation of food intake and energy homeostasis, has made this pathway the target of many academic and industrial research endeavors in attempts to develop potent and selective MC4R small molecules as anti-obesity therapeutic agents. Herein, we attempt to summarize the known proteins that constitute the melanocortin system and discuss advances in peptide and non-peptide drug discovery.
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Affiliation(s)
- Boman G Irani
- University of Florida, Department of Medicinal Chemistry, PO Box 100485, Gainesville, FL 32610-0485, USA.
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