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Gui Y, Dahir NS, Wu Y, Downing G, Sweeney P, Cone RD. Melanocortin-3 receptor expression in AgRP neurons is required for normal activation of the neurons in response to energy deficiency. Cell Rep 2023; 42:113188. [PMID: 37792535 PMCID: PMC10728878 DOI: 10.1016/j.celrep.2023.113188] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/14/2023] [Accepted: 09/14/2023] [Indexed: 10/06/2023] Open
Abstract
The melanocortin-3 receptor (MC3R) is a negative regulator of the central melanocortin circuitry via presynaptic expression on agouti-related protein (AgRP) nerve terminals, from where it regulates GABA release onto secondary MC4R-expressing neurons. However, MC3R knockout (KO) mice also exhibit defective behavioral and neuroendocrine responses to fasting. Here, we demonstrate that MC3R KO mice exhibit defective activation of AgRP neurons in response to fasting, cold exposure, or ghrelin while exhibiting normal inhibition of AgRP neurons by sensory detection of food in the ad libitum-fed state. Using a conditional MC3R KO model, we show that the control of AgRP neuron activation by fasting and ghrelin requires the specific presence of MC3R within AgRP neurons. Thus, MC3R is a crucial player in the responsiveness of the AgRP soma to both hormonal and neuronal signals of energy need.
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Affiliation(s)
- Yijun Gui
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Naima S Dahir
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Yanan Wu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Griffin Downing
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Patrick Sweeney
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana-Champaign, IL 61801-3633, USA
| | - Roger D Cone
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2216, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109-2216, USA.
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Gui Y, Dahir NS, Downing G, Sweeney P, Cone RD. Cell autonomous regulation of the activation of AgRP neurons by the melanocortin-3 receptor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.28.546874. [PMID: 37425887 PMCID: PMC10327035 DOI: 10.1101/2023.06.28.546874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The melanocortin-3 receptor (MC3R) is a negative regulator of the central melanocortin circuitry via presynaptic expression on AgRP nerve terminals, from where it regulates GABA release onto secondary MC4R-expressing neurons. Hence, animals lacking MC3R (MC3R KO) exhibit hypersensitivity to MC4R agonists. However, MC3R KO mice also exhibit defective behavioral and neuroendocrine responses to fasting. Here, we demonstrate that MC3R KO mice exhibit defective activation of AgRP neurons in response to fasting and cold exposure, while exhibiting normal inhibition of AgRP neurons by sensory detection of food. Further, using an AgRP-specific MC3R knockout model, we show that the control of AgRP neuron activation by MC3R is cell-autonomous. One mechanism underlying this involves the response to ghrelin, which is also blunted in mice with AgRP-specific deletion of the MC3R. Thus, MC3R is a crucial player in the control of energy homeostasis by the central melanocortin system, not only acting presynaptically on AgRP neurons, but via AgRP cell-autonomous regulation of fasting- and cold-induced neuronal activation as well.
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Vinnicombe KRT, Volkoff H. Possible role of transcription factors (BSX, NKX2.1, IRX3 and SIRT1) in the regulation of appetite in goldfish (Carassius auratus). Comp Biochem Physiol A Mol Integr Physiol 2022; 268:111189. [PMID: 35307341 DOI: 10.1016/j.cbpa.2022.111189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/13/2022] [Accepted: 03/13/2022] [Indexed: 12/17/2022]
Abstract
The homeobox genes play important roles in the embryonic development of animals. Recent evidence suggests they might also regulate feeding and act as transcription factors of appetite regulators. Examples of these genes are a brain-specific homeobox transcription factor (BSX), NK2 homeobox 1 (NKX2.1) and the Iroquois homeobox 3 (IRX3). Sirtuin1 (SIRT1) acts as a transcription factor for nutrient (e.g. lipid, glucose) homeostasis and responds to stress and nutrient availability, and has been shown to interact with appetite regulators. Very little is known about the role of these genes in the regulation of feeding and nutrient homeostasis in fish. In this study, we assessed the roles of BSX, NKX2.1, IRX3 and SIRT1 in the central regulation of feeding in goldfish by examining their mRNA brain distribution, assessing the effects of fasting on their brain expression and assessing the effects of peripheral injections of cholecystokinin (CCK, a brain-gut peptide), on their brain expression. All genes showed a widespread distribution in the brain, with high levels in the hypothalamus. In both hypothalamus and telencephalon, fasting induced increases in BSX, IRX3 and NKX2.1 expressions but had no effect on SIRT1 expression levels. CCK injections increased hypothalamic expression levels of IRX3 and SIRT1, and telencephalic expression levels of NKX2.1 and SIRT1, with no effect on either hypothalamic BSX or NKX2.1 expression levels or telencephalon BSX or IRX3 expression levels. Our results suggest that, in goldfish as in mammals, central BSX, NKX2.1, IRX3 and SIRT1 are present in regions of the brain regulating feeding, are sensitive to nutrient status and interact with appetite-regulating peptides.
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Affiliation(s)
- Kelsey R T Vinnicombe
- Department of Biology, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada
| | - Helene Volkoff
- Department of Biology, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
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VTA MC3R neurons control feeding in an activity- and sex-dependent manner in mice. Neuropharmacology 2021; 197:108746. [PMID: 34371079 DOI: 10.1016/j.neuropharm.2021.108746] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/29/2021] [Accepted: 08/03/2021] [Indexed: 01/25/2023]
Abstract
Increasing evidence indicates that the melanocortin and mesolimbic dopamine (DA) systems interact to regulate feeding and body weight. Because melanocortin-3 receptors (MC3R) are highly expressed in the ventral tegmental area (VTA), we tested whether VTA neurons expressing these receptors (VTA MC3R neurons) control feeding and body weight in vivo. We also tested whether there were sex differences in the ability of VTA MC3R neurons to control feeding, as MC3R -/- mice show sex-dependent alterations in reward feeding and DA levels, and there are clear sex differences in multiple DA-dependent behaviors and disorders. Designer receptors exclusively activated by designer drugs (DREADD) were used to acutely activate and inhibit VTA MC3R neurons and changes in food intake and body weight were measured. Acutely altering the activity of VTA MC3R neurons decreased feeding in an activity- and sex-dependent manner, with acute activation decreasing feeding, but only in females, and acute inhibition decreasing feeding, but only in males. These differences did not appear to be due to sex differences in the number of VTA MC3R neurons, the ability of hM3Dq to activate VTA MC3R neurons, or the proportion of VTA MC3R neurons expressing tyrosine hydroxylase (TH). These studies demonstrate an important role for VTA MC3R neurons in the control of feeding and reveal important sex differences in behavior, whereby opposing changes in neuronal activity in male and female mice cause similar changes in behavior.
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Micioni Di Bonaventura E, Botticelli L, Tomassoni D, Tayebati SK, Micioni Di Bonaventura MV, Cifani C. The Melanocortin System behind the Dysfunctional Eating Behaviors. Nutrients 2020; 12:E3502. [PMID: 33202557 PMCID: PMC7696960 DOI: 10.3390/nu12113502] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/09/2020] [Accepted: 11/11/2020] [Indexed: 12/11/2022] Open
Abstract
The dysfunction of melanocortin signaling has been associated with obesity, given the important role in the regulation of energy homeostasis, food intake, satiety and body weight. In the hypothalamus, the melanocortin-3 receptor (MC3R) and melanocortin-4 receptor (MC4R) contribute to the stability of these processes, but MC3R and MC4R are also localized in the mesolimbic dopamine system, the region that responds to the reinforcing properties of highly palatable food (HPF) and where these two receptors seem to affect food reward and motivation. Loss of function of the MC4R, resulting from genetic mutations, leads to overeating in humans, but to date, a clear understanding of the underlying mechanisms and behaviors that promote overconsumption of caloric foods remains unknown. Moreover, the MC4R demonstrated to be a crucial modulator of the stress response, factor that is known to be strictly related to binge eating behavior. In this review, we will explore the preclinical and clinical studies, and the controversies regarding the involvement of melanocortin system in altered eating patterns, especially binge eating behavior, food reward and motivation.
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Affiliation(s)
| | - Luca Botticelli
- School of Pharmacy, University of Camerino, 62032 Camerino, Italy; (E.M.D.B.); (L.B.); (S.K.T.); (C.C.)
| | - Daniele Tomassoni
- School of Bioscience and Veterinary Medicine, University of Camerino, 62032 Camerino, Italy;
| | - Seyed Khosrow Tayebati
- School of Pharmacy, University of Camerino, 62032 Camerino, Italy; (E.M.D.B.); (L.B.); (S.K.T.); (C.C.)
| | | | - Carlo Cifani
- School of Pharmacy, University of Camerino, 62032 Camerino, Italy; (E.M.D.B.); (L.B.); (S.K.T.); (C.C.)
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Banerjee S, Ghoshal S, Stevens JR, McCommis KS, Gao S, Castro-Sepulveda M, Mizgier ML, Girardet C, Kumar KG, Galgani JE, Niehoff ML, Farr SA, Zhang J, Butler AA. Hepatocyte expression of the micropeptide adropin regulates the liver fasting response and is enhanced by caloric restriction. J Biol Chem 2020; 295:13753-13768. [PMID: 32727846 DOI: 10.1074/jbc.ra120.014381] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/22/2020] [Indexed: 12/16/2022] Open
Abstract
The micropeptide adropin encoded by the clock-controlled energy homeostasis-associated gene is implicated in the regulation of glucose metabolism. However, its links to rhythms of nutrient intake, energy balance, and metabolic control remain poorly defined. Using surveys of Gene Expression Omnibus data sets, we confirm that fasting suppresses liver adropin expression in lean C57BL/6J (B6) mice. However, circadian rhythm data are inconsistent. In lean mice, caloric restriction (CR) induces bouts of compulsive binge feeding separated by prolonged fasting intervals, increasing NAD-dependent deacetylase sirtuin-1 signaling important for glucose and lipid metabolism regulation. CR up-regulates adropin expression and induces rhythms correlating with cellular stress-response pathways. Furthermore, adropin expression correlates positively with phosphoenolpyruvate carboxokinase-1 (Pck1) expression, suggesting a link with gluconeogenesis. Our previous data suggest that adropin suppresses gluconeogenesis in hepatocytes. Liver-specific adropin knockout (LAdrKO) mice exhibit increased glucose excursions following pyruvate injections, indicating increased gluconeogenesis. Gluconeogenesis is also increased in primary cultured hepatocytes derived from LAdrKO mice. Analysis of circulating insulin levels and liver expression of fasting-responsive cAMP-dependent protein kinase A (PKA) signaling pathways also suggests enhanced responses in LAdrKO mice during a glucagon tolerance test (250 µg/kg intraperitoneally). Fasting-associated changes in PKA signaling are attenuated in transgenic mice constitutively expressing adropin and in fasting mice treated acutely with adropin peptide. In summary, hepatic adropin expression is regulated by nutrient- and clock-dependent extrahepatic signals. CR induces pronounced postprandial peaks in hepatic adropin expression. Rhythms of hepatic adropin expression appear to link energy balance and cellular stress to the intracellular signal transduction pathways that drive the liver fasting response.
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Affiliation(s)
- Subhashis Banerjee
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
| | - Sarbani Ghoshal
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
| | - Joseph R Stevens
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
| | - Kyle S McCommis
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri, USA; Center for Cardiovascular Research, Saint Louis University School of Medicine, St. Louis, Missouri, USA; Saint Louis University Liver Center, Saint Louis University School of Medicine, St. Louis, Missouri USA
| | - Su Gao
- Department of Metabolism and Aging, Scripps Research Institute, Jupiter, Florida, USA
| | - Mauricio Castro-Sepulveda
- Laboratorio de Ciencias del Ejercicio. Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile
| | - Maria L Mizgier
- Departamento de Ciencias de la SaludCarrera de Nutrición y Dietética and Departamento de Nutrición, Diabetes y Metabolismo, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Clemence Girardet
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
| | - K Ganesh Kumar
- Department of Metabolism and Aging, Scripps Research Institute, Jupiter, Florida, USA
| | - Jose E Galgani
- Departamento de Ciencias de la SaludCarrera de Nutrición y Dietética and Departamento de Nutrición, Diabetes y Metabolismo, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Michael L Niehoff
- Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, St. Louis, Missouri, USA; Division of Geriatric Medicine, Saint Louis University School of Medicine, St. Louis, Saint Louis University School of Medicine; Research Service, John Cochran Division, Saint Louis Veterans Affairs Medical Center, Missouri, USA
| | - Susan A Farr
- Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, St. Louis, Missouri, USA; Division of Geriatric Medicine, Saint Louis University School of Medicine, St. Louis, Saint Louis University School of Medicine; Research Service, John Cochran Division, Saint Louis Veterans Affairs Medical Center, Missouri, USA
| | - Jinsong Zhang
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
| | - Andrew A Butler
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri, USA; Department of Metabolism and Aging, Scripps Research Institute, Jupiter, Florida, USA; Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, St. Louis, Missouri, USA.
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Baldini G, Phelan KD. The melanocortin pathway and control of appetite-progress and therapeutic implications. J Endocrinol 2019; 241:R1-R33. [PMID: 30812013 PMCID: PMC6500576 DOI: 10.1530/joe-18-0596] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 01/22/2019] [Indexed: 12/19/2022]
Abstract
The initial discovery that ob/ob mice become obese because of a recessive mutation of the leptin gene has been crucial to discover the melanocortin pathway to control appetite. In the melanocortin pathway, the fed state is signaled by abundance of circulating hormones such as leptin and insulin, which bind to receptors expressed at the surface of pro-opiomelanocortin (POMC) neurons to promote processing of POMC to the mature hormone α-melanocyte-stimulating hormone (α-MSH). The α-MSH released by POMC neurons then signals to decrease energy intake by binding to melanocortin-4 receptor (MC4R) expressed by MC4R neurons to the paraventricular nucleus (PVN). Conversely, in the 'starved state' activity of agouti-related neuropeptide (AgRP) and of neuropeptide Y (NPY)-expressing neurons is increased by decreased levels of circulating leptin and insulin and by the orexigenic hormone ghrelin to promote food intake. This initial understanding of the melanocortin pathway has recently been implemented by the description of the complex neuronal circuit that controls the activity of POMC, AgRP/NPY and MC4R neurons and downstream signaling by these neurons. This review summarizes the progress done on the melanocortin pathway and describes how obesity alters this pathway to disrupt energy homeostasis. We also describe progress on how leptin and insulin receptors signal in POMC neurons, how MC4R signals and how altered expression and traffic of MC4R change the acute signaling and desensitization properties of the receptor. We also describe how the discovery of the melanocortin pathway has led to the use of melanocortin agonists to treat obesity derived from genetic disorders.
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Affiliation(s)
- Giulia Baldini
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Kevin D. Phelan
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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Fleming KA, Freeman KT, Powers MD, Santos RG, Debevec G, Giulianotti MA, Houghten RA, Doering SR, Pinilla C, Haskell-Luevano C. Discovery of Polypharmacological Melanocortin-3 and -4 Receptor Probes and Identification of a 100-Fold Selective nM MC3R Agonist versus a μM MC4R Partial Agonist. J Med Chem 2019; 62:2738-2749. [PMID: 30741545 DOI: 10.1021/acs.jmedchem.9b00053] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The centrally expressed melanocortin-3 and melanocortin-4 receptors (MC3R and MC4R, respectively) are established targets to treat diseases of positive- and negative-energy homeostasis. We previously reported [ Doering , S. R. ; J. Med. Chem. 2017 , 60 , 4342 - 4357 ] mixture-based positional scanning approaches to identify dual MC3R agonist and MC4R antagonist tetrapeptides. Herein, 46 tetrapeptides were chosen for MC3R agonist screening selectivity profiles, synthesized, and pharmacologically characterized at the mouse melanocortin-1, -3, -4, and -5 receptors. Substitutions to the tetrapeptide template were selected solely based on MC3R agonist potency from the mixture-based screen. This study resulted in the discovery of compound 42 (Ac-Val-Gln-(pI)DPhe-DTic-NH2), a full MC3R agonist that is 100-fold selective for the MC3R over the μM MC4R partial agonist pharmacology. This compound represents a first-in-class MC3R selective agonist. This ligand will serve as a useful in vivo molecular probe for the investigation of the roles of the MC3R and MC4R in diseases of dysregulated energy homeostasis.
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Affiliation(s)
- Katlyn A Fleming
- Department of Medicinal Chemistry , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Katie T Freeman
- Department of Medicinal Chemistry , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Mike D Powers
- Department of Medicinal Chemistry , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Radleigh G Santos
- Torrey Pines Institute for Molecular Studies , Port St. Lucie , Florida 34987 , United States
| | - Ginamarie Debevec
- Torrey Pines Institute for Molecular Studies , Port St. Lucie , Florida 34987 , United States
| | - Marc A Giulianotti
- Torrey Pines Institute for Molecular Studies , Port St. Lucie , Florida 34987 , United States
| | - Richard A Houghten
- Torrey Pines Institute for Molecular Studies , Port St. Lucie , Florida 34987 , United States
| | - Skye R Doering
- Department of Medicinal Chemistry , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | | | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry , University of Minnesota , Minneapolis , Minnesota 55455 , United States
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Girardet C, Marks DL, Butler AA. Melanocortin-3 Receptors Expressed on Agouti-Related Peptide Neurons Inhibit Feeding Behavior in Female Mice. Obesity (Silver Spring) 2018; 26:1849-1855. [PMID: 30426710 PMCID: PMC7294842 DOI: 10.1002/oby.22306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/27/2018] [Accepted: 07/30/2018] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Activation of hypothalamic agouti-related peptide expressing (AgRP)+ve neurons during energy deficit is a negative valence signal, rapidly activating food-seeking behaviors. This study examined the roles of melanocortin-3 receptors (MC3Rs) coexpressed in a subpopulation of AgRP+ve neurons. METHODS AgRP-MC3R mice expressing MC3Rs selectively in AgRP+ve neurons were generated by crossing AgRP-IRES-Cre mice with LoxTBMc3r mice containing a "loxP-STOP-loxP" sequence in the 5' untranslated region. Body weight, body composition, and feeding behavior were assessed during ad libitum and time-restricted feeding conditions. RESULTS In females, food intake of AgRP-IRES-Cre+ve (n = 7) or AgRP-IRES-Cre-ve (n = 9) mice was not significantly different; these mice were therefore pooled to form the "control" group. Female AgRP-MC3R mice exhibited lower food intake (25.4 ± 2.4 kJ/12 h; n = 6) compared with controls (35.3 ± 1.8 kJ/12 h; n = 16) and LoxTBMc3r mice (32.1 ± 2.1 kJ/12 h; n = 9) in the active phase during the dark period. Food intake during the rest phase (lights on) when mice consume less food (9-10 kJ) was normal between genotypes. Body weight and composition of AgRP-MC3R and LoxTBMc3r mice were similar, suggesting compensatory mechanisms for reduced calorie intake. Remarkably, AgRP-MC3R mice continued to consume less food during refeeding after fasting and time-restricted feeding. CONCLUSIONS MC3Rs expressed on AgRP+ve neurons appear to exert a strong inhibitory signal on hypothalamic networks governing feeding behavior.
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Affiliation(s)
- Clemence Girardet
- Department of Pharmacology & Physiology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Daniel L. Marks
- Department of Pediatrics, Papé Family Pediatric Research Institute, Oregon Health & Science University, Mail Code L481 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA
| | - Andrew A. Butler
- Department of Pharmacology & Physiology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
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Eerola K, Virtanen S, Vähätalo L, Ailanen L, Cai M, Hruby V, Savontaus M, Savontaus E. Hypothalamic γ-melanocyte stimulating hormone gene delivery reduces fat mass in male mice. J Endocrinol 2018; 239:19–31. [PMID: 30307151 DOI: 10.1530/joe-18-0009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
γ-Melanocyte stimulating hormone (γ-MSH) is an endogenous agonist of the melanocortin 3-receptor (MC3R). Genetic disruption of MC3Rs increases adiposity and blunts responses to fasting, suggesting that increased MC3R signaling could be physiologically beneficial in the long term. Interestingly, several studies have concluded that activation of MC3Rs is orexigenic in the short term. Therefore, we aimed to examine the short- and long-term effects of γ-MSH in the hypothalamic arcuate nucleus (ARC) on energy homeostasis and hypothesized that the effect of MC3R agonism is dependent on the state of energy balance and nutrition. Lentiviral gene delivery was used to induce a continuous expression of γ-Msh only in the ARC of male C57Bl/6N mice. Parameters of body energy homeostasis were monitored as food was changed from chow (6 weeks) to Western diet (13 weeks) and back to chow (7 weeks). The γ-MSH treatment decreased the fat mass to lean mass ratio on chow, but the effect was attenuated on Western diet. After the switch back to chow, an enhanced loss in weight (−15% vs −6%) and fat mass (−37% vs −12%) and reduced cumulative food intake were observed in γ-MSH-treated animals. Fasting-induced feeding was increased on chow diet only; however, voluntary running wheel activity on Western diet was increased. The γ-MSH treatment also modulated the expression of key neuropeptides in the ARC favoring weight loss. We have shown that a chronic treatment intended to target ARC MC3Rs modulates energy balance in nutritional state-dependent manner. Enhancement of diet-induced weight loss could be beneficial in treatment of obesity.
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Affiliation(s)
- K Eerola
- Institute of Biomedicine, Research Center for Integrative Physiology and Pharmacology and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Turku Centre for Biotechnology, University of Turku, Turku, Finland
| | - S Virtanen
- Institute of Biomedicine, Research Center for Integrative Physiology and Pharmacology and Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - L Vähätalo
- Institute of Biomedicine, Research Center for Integrative Physiology and Pharmacology and Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - L Ailanen
- Institute of Biomedicine, Research Center for Integrative Physiology and Pharmacology and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Drug Research Doctoral Program, University of Turku, Turku, Finland
| | - M Cai
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - V Hruby
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - M Savontaus
- Turku Centre for Biotechnology, University of Turku, Turku, Finland
- Heart Center, Turku University Hospital and University of Turku, Turku, Finland
| | - E Savontaus
- Institute of Biomedicine, Research Center for Integrative Physiology and Pharmacology and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Unit of Clinical Pharmacology, Turku University Hospital, Turku, Finland
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11
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Fleming KA, Freeman KT, Ericson MD, Haskell-Luevano C. Synergistic Multiresidue Substitutions of a Macrocyclic c[Pro-Arg-Phe-Phe-Asn-Ala-Phe-dPro] Agouti-Related Protein (AGRP) Scaffold Yield Potent and >600-Fold MC4R versus MC3R Selective Melanocortin Receptor Antagonists. J Med Chem 2018; 61:7729-7740. [PMID: 30035543 PMCID: PMC6174881 DOI: 10.1021/acs.jmedchem.8b00684] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Antagonist ligands of the melanocortin-3 and -4 receptors (MC3R, MC4R), including agouti-related protein (AGRP), are postulated to be targets for the treatment of diseases of negative energy balance. Previous studies reported the macrocyclic MC3R/MC4R antagonist c[Pro1-Arg2-Phe3-Phe4-Asn5-Ala6-Phe7-dPro8], which is 250-fold less potent at the mouse (m) mMC3R and 3-fold less potent at the mMC4R than AGRP. Previous studies explored the structure-activity relationships around individual positions in this template. Herein, a multiresidue substitution strategy is utilized, combining the lead sequence with hPhe4, Dap5, Arg5, Ser6, and Nle7 substitutions previously reported. Two compounds from this study (16, 20) contain an hPhe4/Ser6/Nle7 substitution pattern, are 3-6-fold more potent than AGRP at the mMC4R and are 600-800-fold selective for the mMC4R over the mMC3R. Another lead compound (21), possessing the hPhe4/Arg5 substitutions, is only 5-fold less potent than AGRP at the mMC3R and is equipotent to AGRP at the mMC4R.
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Affiliation(s)
- Katlyn A. Fleming
- University of Minnesota, Department of Medicinal Chemistry and Institute for Translation Neuroscience, Minneapolis, Minnesota 55455, United States
| | - Katie T. Freeman
- University of Minnesota, Department of Medicinal Chemistry and Institute for Translation Neuroscience, Minneapolis, Minnesota 55455, United States
| | - Mark D. Ericson
- University of Minnesota, Department of Medicinal Chemistry and Institute for Translation Neuroscience, Minneapolis, Minnesota 55455, United States
| | - Carrie Haskell-Luevano
- University of Minnesota, Department of Medicinal Chemistry and Institute for Translation Neuroscience, Minneapolis, Minnesota 55455, United States
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Ghamari-Langroudi M, Cakir I, Lippert RN, Sweeney P, Litt MJ, Ellacott KLJ, Cone RD. Regulation of energy rheostasis by the melanocortin-3 receptor. SCIENCE ADVANCES 2018; 4:eaat0866. [PMID: 30140740 PMCID: PMC6105298 DOI: 10.1126/sciadv.aat0866] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 07/18/2018] [Indexed: 05/19/2023]
Abstract
Like most homeostatic systems, adiposity in mammals is defended between upper and lower boundary conditions. While leptin and melanocortin-4 receptor (MC4R) signaling are required for defending energy set point, mechanisms controlling upper and lower homeostatic boundaries are less well understood. In contrast to the MC4R, deletion of the MC3R does not produce measurable hyperphagia or hypometabolism under normal conditions. However, we demonstrate that MC3R is required bidirectionally for controlling responses to external homeostatic challenges, such as caloric restriction or calorie-rich diet. MC3R is also required for regulated excursion from set point, or rheostasis, during pregnancy. Further, we demonstrate a molecular mechanism: MC3R provides regulatory inputs to melanocortin signaling, acting presynaptically on agouti-related protein neurons to regulate γ-aminobutyric acid release onto anorexigenic MC4R neurons, exerting boundary control on the activity of MC4R neurons. Thus, the MC3R is a critical regulator of boundary controls on melanocortin signaling, providing rheostatic control on energy storage.
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Affiliation(s)
- Masoud Ghamari-Langroudi
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 702 Light Hall, Nashville, TN 37232, USA
- Corresponding author. (M.G.-L.); (R.D.C.)
| | - Isin Cakir
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 702 Light Hall, Nashville, TN 37232, USA
- Life Sciences Institute and Department of Molecular and Integrative Physiology, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109–2216, USA
| | - Rachel N. Lippert
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 702 Light Hall, Nashville, TN 37232, USA
- Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Patrick Sweeney
- Life Sciences Institute and Department of Molecular and Integrative Physiology, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109–2216, USA
| | - Michael J. Litt
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 702 Light Hall, Nashville, TN 37232, USA
| | - Kate L. J. Ellacott
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 702 Light Hall, Nashville, TN 37232, USA
- University of Exeter Medical School, Exeter, UK
| | - Roger D. Cone
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 702 Light Hall, Nashville, TN 37232, USA
- Life Sciences Institute and Department of Molecular and Integrative Physiology, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109–2216, USA
- Corresponding author. (M.G.-L.); (R.D.C.)
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Novoselova TV, Chan LF, Clark AJL. Pathophysiology of melanocortin receptors and their accessory proteins. Best Pract Res Clin Endocrinol Metab 2018; 32:93-106. [PMID: 29678289 DOI: 10.1016/j.beem.2018.02.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The melanocortin receptors (MCRs) and their accessory proteins (MRAPs) are involved in regulation of a diverse range of endocrine pathways. Genetic variants of these components result in phenotypic variation and disease. The MC1R is expressed in skin and variants in the MC1R gene are associated with ginger hair color. The MC2R mediates the action of ACTH in the adrenal gland to stimulate glucocorticoid production and MC2R mutations result in familial glucocorticoid deficiency (FGD). MC3R and MC4R are involved in metabolic regulation and their gene variants are associated with severe pediatric obesity, whereas the function of MC5R remains to be fully elucidated. MRAPs have been shown to modulate the function of MCRs and genetic variants in MRAPs are associated with diseases including FGD type 2 and potentially early onset obesity. This review provides an insight into recent advances in MCRs and MRAPs physiology, focusing on the disorders associated with their dysfunction.
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Affiliation(s)
- T V Novoselova
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London, Chartehouse Square, London, EC1M 6BQ, United Kingdom.
| | - L F Chan
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London, Chartehouse Square, London, EC1M 6BQ, United Kingdom
| | - A J L Clark
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London, Chartehouse Square, London, EC1M 6BQ, United Kingdom
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Butler AA, Girardet C, Mavrikaki M, Trevaskis JL, Macarthur H, Marks DL, Farr SA. A Life without Hunger: The Ups (and Downs) to Modulating Melanocortin-3 Receptor Signaling. Front Neurosci 2017; 11:128. [PMID: 28360832 PMCID: PMC5352694 DOI: 10.3389/fnins.2017.00128] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 03/01/2017] [Indexed: 11/13/2022] Open
Abstract
Melanocortin neurons conserve body mass in hyper- or hypo-caloric conditions by conveying signals from nutrient sensors into areas of the brain governing appetite and metabolism. In mice, melanocortin-3 receptor (MC3R) deletion alters nutrient partitioning independently of hyperphagia, promoting accumulation of fat over muscle mass. Enhanced rhythms in insulin and insulin-responsive metabolic genes during hypocaloric feeding suggest partial insulin resistance and enhanced lipogenesis. However, exactly where and how MC3Rs affect metabolic control to alter nutrient partitioning is not known. The behavioral phenotypes exhibited by MC3R-deficient mice suggest a contextual role in appetite control. The impact of MC3R-deficiency on feeding behavior when food is freely available is minor. However, homeostatic responses to hypocaloric conditioning involving increased expression of appetite-stimulating (orexigenic) neuropeptides, binge-feeding, food anticipatory activity (FAA), entrainment to nutrient availability and enhanced feeding-related motivational responses are compromised with MC3R-deficiency. Rescuing Mc3r transcription in hypothalamic and limbic neurons improves appetitive responses during hypocaloric conditioning while having minor effects on nutrient partitioning, suggesting orexigenic functions. Rescuing hypothalamic MC3Rs also restores responses of fasting-responsive hypothalamic orexigenic neurons in hypocaloric conditions, suggesting actions that sensitize fasting-responsive neurons to signals from nutrient sensors. MC3R signaling in ventromedial hypothalamic SF1(+ve) neurons improves metabolic control, but does not restore appetitive responses or nutrient partitioning. In summary, desensitization of fasting-responsive orexigenic neurons may underlie attenuated appetitive responses of MC3R-deficient mice in hypocaloric situations. Further studies are needed to identify the specific location(s) of MC3Rs controlling appetitive responses and partitioning of nutrients between fat and lean tissues.
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Affiliation(s)
- Andrew A Butler
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine St. Louis, MO, USA
| | - Clemence Girardet
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine St. Louis, MO, USA
| | - Maria Mavrikaki
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine St. Louis, MO, USA
| | - James L Trevaskis
- In vivo Pharmacology, Cardiovascular and Metabolic Disease, Medimmune Gaithersburg, MD, USA
| | - Heather Macarthur
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine St. Louis, MO, USA
| | - Daniel L Marks
- Papé Family Pediatric Research Institute, Oregon Health and Science University Portland, OR, USA
| | - Susan A Farr
- Department of Internal Medicine, Division of Geriatrics, Saint Louis University School of MedicineSt. Louis, MO, USA; VA Medical CenterSt. Louis, MO, USA
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