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Wang M, Lyu J, Zhang C. Single transmembrane GPCR modulating proteins: neither single nor simple. Protein Cell 2024; 15:395-402. [PMID: 37314044 PMCID: PMC11131010 DOI: 10.1093/procel/pwad035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 05/22/2023] [Indexed: 06/15/2023] Open
Affiliation(s)
- Meng Wang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China
| | - Jianjun Lyu
- Hubei Topgene Research Institute of Hubei Topgene Biotechnology Co., Ltd, East Lake High-Tech Development Zone, Wuhan 430205, China
| | - Chao Zhang
- Fundamental Research Center, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), Tongji University, Shanghai 200092, China
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2
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Lattanzi R, Casella I, Fullone MR, Maftei D, Vincenzi M, Miele R. MRAP2 Inhibits β-Arrestin-2 Recruitment to the Prokineticin Receptor 2. Curr Issues Mol Biol 2024; 46:1607-1620. [PMID: 38392222 PMCID: PMC10887741 DOI: 10.3390/cimb46020104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/05/2024] [Accepted: 02/14/2024] [Indexed: 02/24/2024] Open
Abstract
Melanocortin receptor accessory protein 2 (MRAP2) is a membrane protein that binds multiple G protein-coupled receptors (GPCRs) involved in the control of energy homeostasis, including prokineticin receptors. These GPCRs are expressed both centrally and peripherally, and their endogenous ligands are prokineticin 1 (PK1) and prokineticin 2 (PK2). PKRs couple all G-protein subtypes, such as Gαq/11, Gαs, and Gαi, and recruit β-arrestins upon PK2 stimulation, although the interaction between PKR2 and β-arrestins does not trigger receptor internalisation. MRAP2 inhibits the anorexigenic effect of PK2 by binding PKR1 and PKR2. The aim of this work was to elucidate the role of MRAP2 in modulating PKR2-induced β-arrestin-2 recruitment and β-arrestin-mediated signalling. This study could allow the identification of new specific targets for potential new drugs useful for the treatment of the various pathologies correlated with prokineticin, in particular, obesity.
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Affiliation(s)
- Roberta Lattanzi
- Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Ida Casella
- National Centre for Drug Research and Evaluation, Istituto Superiore di Sanità, 00161 Rome, Italy
| | - Maria Rosaria Fullone
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Daniela Maftei
- Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Martina Vincenzi
- Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Rossella Miele
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
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3
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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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4
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Sweeney P, Gimenez LE, Hernandez CC, Cone RD. Targeting the central melanocortin system for the treatment of metabolic disorders. Nat Rev Endocrinol 2023; 19:507-519. [PMID: 37365323 DOI: 10.1038/s41574-023-00855-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/18/2023] [Indexed: 06/28/2023]
Abstract
A large body of preclinical and clinical data shows that the central melanocortin system is a promising therapeutic target for treating various metabolic disorders such as obesity and cachexia, as well as anorexia nervosa. Setmelanotide, which functions by engaging the central melanocortin circuitry, was approved by the FDA in 2020 for use in certain forms of syndromic obesity. Furthermore, the FDA approvals in 2019 of two peptide drugs targeting melanocortin receptors for the treatment of generalized hypoactive sexual desire disorder (bremelanotide) and erythropoietic protoporphyria-associated phototoxicity (afamelanotide) demonstrate the safety of this class of peptides. These approvals have also renewed excitement in the development of therapeutics targeting the melanocortin system. Here, we review the anatomy and function of the melanocortin system, discuss progress and challenges in developing melanocortin receptor-based therapeutics, and outline potential metabolic and behavioural disorders that could be addressed using pharmacological agents targeting these receptors.
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Affiliation(s)
- Patrick Sweeney
- School of Molecular and Cellular Biology, College of Liberal Arts and Sciences, University of Illinois Urbana-Champaign, Champaign, IL, USA
| | - Luis E Gimenez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | | | - Roger D Cone
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
- Department of Molecular and Integrative Physiology, School of Medicine, University of Michigan, Ann Arbor, MI, USA.
- Department of Molecular, Cellular, and Developmental Biology, College of Literature Science and the Arts, University of Michigan, Ann Arbor, MI, USA.
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5
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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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6
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Jamaluddin A, Gorvin CM. RISING STARS: Targeting G protein-coupled receptors to regulate energy homeostasis. J Mol Endocrinol 2023; 70:e230014. [PMID: 36943057 PMCID: PMC10160555 DOI: 10.1530/jme-23-0014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 03/21/2023] [Indexed: 03/23/2023]
Abstract
G protein-coupled receptors (GPCRs) have a critical role in energy homeostasis, contributing to food intake, energy expenditure and glycaemic control. Dysregulation of energy expenditure can lead to metabolic syndrome (abdominal obesity, elevated plasma triglyceride, LDL cholesterol and glucose, and high blood pressure), which is associated with an increased risk of developing obesity, diabetes mellitus, non-alcoholic fatty liver disease and cardiovascular complications. As the prevalence of these chronic diseases continues to rise worldwide, there is an increased need to understand the molecular mechanisms by which energy expenditure is regulated to facilitate the development of effective therapeutic strategies to treat and prevent these conditions. In recent years, drugs targeting GPCRs have been the focus of efforts to improve treatments for type-2 diabetes and obesity, with GLP-1R agonists a particular success. In this review, we focus on nine GPCRs with roles in energy homeostasis that are current and emerging targets to treat obesity and diabetes. We discuss findings from pre-clinical models and clinical trials of drugs targeting these receptors and challenges that must be overcome before these drugs can be routinely used in clinics. We also describe new insights into how these receptors signal, including how accessory proteins, biased signalling, and complex spatial signalling could provide unique opportunities to develop more efficacious therapies with fewer side effects. Finally, we describe how combined therapies, in which multiple GPCRs are targeted, may improve clinical outcomes and reduce off-target effects.
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Affiliation(s)
- Aqfan Jamaluddin
- Institute of Metabolism and Systems Research (IMSR) and Centre for Diabetes, Endocrinology and Metabolism (CEDAM), University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Birmingham, UK
| | - Caroline M Gorvin
- Institute of Metabolism and Systems Research (IMSR) and Centre for Diabetes, Endocrinology and Metabolism (CEDAM), University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Birmingham, UK
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7
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Gross JD, Zhou Y, Barak LS, Caron MG. Ghrelin receptor signaling in health and disease: a biased view. Trends Endocrinol Metab 2023; 34:106-118. [PMID: 36567228 PMCID: PMC9852078 DOI: 10.1016/j.tem.2022.12.001] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/23/2022] [Accepted: 12/06/2022] [Indexed: 12/25/2022]
Abstract
As allosteric complexes, G-protein-coupled receptors (GPCRs) respond to extracellular stimuli and pleiotropically couple to intracellular transducers to elicit signaling pathway-dependent effects in a process known as biased signaling or functional selectivity. One such GPCR, the ghrelin receptor (GHSR1a), has a crucial role in restoring and maintaining metabolic homeostasis during disrupted energy balance. Thus, pharmacological modulation of GHSR1a bias could offer a promising strategy to treat several metabolism-based disorders. Here, we summarize current evidence supporting GHSR1a functional selectivity in vivo and highlight recent structural data. We propose that precise determinations of GHSR1a molecular pharmacology and pathway-specific physiological effects will enable discovery of GHSR1a drugs with tailored signaling profiles, thereby providing safer and more effective treatments for metabolic diseases.
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Affiliation(s)
- Joshua D Gross
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Yang Zhou
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Lawrence S Barak
- Department of Cell Biology, Duke University, Durham, NC 27710, USA.
| | - Marc G Caron
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
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8
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Bernard A, Ojeda Naharros I, Yue X, Mifsud F, Blake A, Bourgain-Guglielmetti F, Ciprin J, Zhang S, McDaid E, Kim K, Nachury MV, Reiter JF, Vaisse C. MRAP2 regulates energy homeostasis by promoting primary cilia localization of MC4R. JCI Insight 2023; 8:e155900. [PMID: 36692018 PMCID: PMC9977312 DOI: 10.1172/jci.insight.155900] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 11/30/2022] [Indexed: 01/24/2023] Open
Abstract
The G protein-coupled receptor melanocortin-4 receptor (MC4R) and its associated protein melanocortin receptor-associated protein 2 (MRAP2) are essential for the regulation of food intake and body weight in humans. MC4R localizes and functions at the neuronal primary cilium, a microtubule-based organelle that senses and relays extracellular signals. Here, we demonstrate that MRAP2 is critical for the weight-regulating function of MC4R neurons and the ciliary localization of MC4R. More generally, our study also reveals that GPCR localization to primary cilia can require specific accessory proteins that may not be present in heterologous cell culture systems. Our findings further demonstrate that targeting of MC4R to neuronal primary cilia is essential for the control of long-term energy homeostasis and suggest that genetic disruption of MC4R ciliary localization may frequently underlie inherited forms of obesity.
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Affiliation(s)
| | | | - Xinyu Yue
- Department of Medicine and The Diabetes Center
| | | | - Abbey Blake
- Department of Medicine and The Diabetes Center
| | | | | | - Sumei Zhang
- Department of Medicine and The Diabetes Center
| | - Erin McDaid
- Department of Medicine and The Diabetes Center
| | - Kellan Kim
- Department of Medicine and The Diabetes Center
| | | | - Jeremy F. Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, UCSF, San Francisco, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
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9
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Yin TC, Mittal A, Buscaglia P, Li W, Sebag JA. Activation of amygdala prokineticin receptor 2 neurons drives the anorexigenic activity of the neuropeptide PK2. J Biol Chem 2022; 299:102814. [PMID: 36539034 PMCID: PMC9860486 DOI: 10.1016/j.jbc.2022.102814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/09/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Energy homeostasis is a complex system involving multiple hormones, neuropeptides, and receptors. Prokineticins (PK1 and PK2) are agonists to two G protein-coupled receptors, prokineticin receptor 1 and 2 (PKR1 and PKR2), which decrease food intake when injected in rodents. The relative contribution of PKR1 and PKR2 to the anorexigenic effect of PK2 and their site of action in the brain have not yet been elucidated. While PKR1 and PKR2 are both expressed in the hypothalamus, a central region involved in the control of energy homeostasis, PKR2 is also present in the amygdala, which has recently been shown to regulate food intake in response to several anorexigenic signals. PKR trafficking and signaling are inhibited by the melanocortin receptor accessory protein 2 (MRAP2), thus suggesting that MRAP2 has the potential to alter the anorexigenic activity of PK2 in vivo. In this study, we investigated the importance of PKR1 and PKR2 for PK2-mediated inhibition of food intake, the brain region involved in this function, and the effect of MRAP2 on PK2 action in vivo. Using targeted silencing of PKR2 and chemogenetic manipulation of PKR2 neurons, we show that the anorexigenic effect of PK2 is mediated by PKR2 in the amygdala and that altering MRAP2 expression in PKR2 neurons modulates the activity of PK2. Collectively, our results provide evidence that inhibition of food intake by PKs is not mediated through activation of hypothalamic neurons but rather amygdala PKR2 neurons and further establishes the importance of MRAP2 in the regulation of energy homeostasis.
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Affiliation(s)
- Terry C. Yin
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA,Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA,Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, USA
| | - Ayushi Mittal
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA,Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA,Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, USA
| | - Paul Buscaglia
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA,Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA,Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, USA
| | - Wenxian Li
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA,Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA,Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, USA
| | - Julien A. Sebag
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA,Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA,Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, USA,For correspondence: Julien A. Sebag
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10
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Wang M, Wang X, Jiang B, Zhai Y, Zheng J, Yang L, Tai X, Li Y, Fu S, Xu J, Lei X, Kuang Z, Zhang C, Bai X, Li M, Zan T, Qu S, Li Q, Zhang C. Identification of MRAP protein family as broad-spectrum GPCR modulators. Clin Transl Med 2022; 12:e1091. [PMID: 36314066 PMCID: PMC9619224 DOI: 10.1002/ctm2.1091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND The melanocortin receptor accessory proteins (MRAP1 and MRAP2) are well-known endocrine regulators for the trafficking and signalling of all five melanocortin receptors (MC1R-MC5R). The observation of MRAP2 on regulating several non-melanocortin G protein-coupled receptors (GPCRs) has been sporadically reported, whereas other endogenous GPCR partners of the MRAP protein family are largely unknown. METHODS Here, we performed single-cell transcriptome analysis and drew a fine GPCR blueprint and MRAPs-associated network of two major endocrine organs, the hypothalamus and adrenal gland at single-cell resolution. We also integrated multiple bulk RNA-seq profiles and single-cell datasets of human and mouse tissues, and narrowed down a list of 48 GPCRs with strong endogenous co-expression correlation with MRAPs. RESULTS 36 and 46 metabolic-related GPCRs were consequently identified as novel interacting partners of MRAP1 or MRAP2, respectively. MRAPs exhibited protein-protein interactions and varying pharmacological properties on the surface translocation, constitutive activities and ligand-stimulated downstream signalling of these GPCRs. Knockdown of MRAP2 expression by hypothalamic administration of adeno-associated virus (AAV) packed shRNA stimulated body weight gain in mouse model. Co-injection of corticotropinreleasing factor (CRF), the agonist of corticotropin releasing hormone receptor 1 (CRHR1), suppressed feeding behaviour in a MRAP2-dependent manner. CONCLUSIONS Collectively, our study has comprehensively elucidated the complex GPCR networks in two major endocrine organs and redefined the MRAP protein family as broad-spectrum GPCR modulators. MRAP proteins not only serve as a vital endocrine pivot on the regulation of global GPCR activities in vivo that could explain the composite physiological phenotypes of the MRAP2 null murine model but also provide us with new insights of the phenotyping investigation of GPCR-MRAP functional complexes.
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Affiliation(s)
- Meng Wang
- Department of Plastic and Reconstructive SurgeryShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Xiaozhu Wang
- Department of Plastic and Reconstructive SurgeryShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Bopei Jiang
- School of Life Sciences and TechnologyTongji UniversityShanghaiChina
| | - Yue Zhai
- School of Life Sciences and TechnologyTongji UniversityShanghaiChina
| | - Jihong Zheng
- School of Life Sciences and TechnologyTongji UniversityShanghaiChina
| | - Liu Yang
- Department of Endocrinology and MetabolismNational Metabolic Management CenterShanghai Tenth People's HospitalSchool of MedicineTongji UniversityShanghaiChina
| | - Xiaolu Tai
- School of Life Sciences and TechnologyTongji UniversityShanghaiChina
| | - Yunpeng Li
- School of Life Sciences and TechnologyTongji UniversityShanghaiChina
| | - Shaliu Fu
- School of Life Sciences and TechnologyTongji UniversityShanghaiChina
| | - Jing Xu
- School of Life Sciences and TechnologyTongji UniversityShanghaiChina
| | - Xiaowei Lei
- School of Life Sciences and TechnologyTongji UniversityShanghaiChina
| | - Zhe Kuang
- School of Life Sciences and TechnologyTongji UniversityShanghaiChina
| | - Cong Zhang
- Department of Plastic and Reconstructive SurgeryShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Xuanxuan Bai
- School of Life Sciences and TechnologyTongji UniversityShanghaiChina
| | - Mingyu Li
- Fujian Provincial Key Laboratory of Innovative Drug Target ResearchSchool of Pharmaceutical SciencesXiamen UniversityXiamenChina
| | - Tao Zan
- Department of Plastic and Reconstructive SurgeryShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Shen Qu
- Department of Endocrinology and MetabolismNational Metabolic Management CenterShanghai Tenth People's HospitalSchool of MedicineTongji UniversityShanghaiChina
| | - Qingfeng Li
- Department of Plastic and Reconstructive SurgeryShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Chao Zhang
- Department of Plastic and Reconstructive SurgeryShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
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11
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Ringuet MT, Furness JB, Furness SGB. G protein-coupled receptor interactions and modification of signalling involving the ghrelin receptor, GHSR1a. J Neuroendocrinol 2022; 34:e13077. [PMID: 34931385 DOI: 10.1111/jne.13077] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/05/2021] [Indexed: 12/28/2022]
Abstract
The growth hormone secretagogue receptor 1a (GHSR1a) is intriguing because of its potential as a therapeutic target and its diverse molecular interactions. Initial studies of the receptor focused on the potential therapeutic ability for growth hormone (GH) release to reduce wasting in aging individuals, as well as food intake regulation for treatment of cachexia. Known roles of GHSR1a now extend to regulation of neurogenesis, learning and memory, gastrointestinal motility, glucose/lipid metabolism, the cardiovascular system, neuronal protection, motivational salience, and hedonic feeding. Ghrelin, the endogenous agonist of GHSR1a, is primarily located in the stomach and is absent from the central nervous system (CNS), including the spinal cord. However, ghrelin in the circulation does have access to a small number of CNS sites, including the arcuate nucleus, which is important in feeding control. At some sites, such as at somatotrophs, GHSR1a has high constitutive activity. Typically, ghrelin-dependent and constitutive GHSR1a activation occurs via Gαq/11 pathways. In vitro and in vivo data suggest that GHSR1a heterodimerises with multiple G protein-coupled receptors (GPCRs), including dopamine D1 and D2, serotonin 2C, orexin, oxytocin and melanocortin 3 receptors (MCR3), as well as the MCR3 accessory protein, MRAP2, providing possible mechanisms for its many physiological effects. In all cases, the receptor interaction changes downstream signalling and the responses to receptor agonists. This review discusses the signalling mechanisms of GHSR1a alone and in combination with other GPCRs, and explores the physiological consequences of GHSR1a coupling with other GPCRs.
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Affiliation(s)
- Mitchell Ty Ringuet
- Department of Anatomy and Physiology, University of Melbourne, Parkville, VIC, Australia
| | - John Barton Furness
- Department of Anatomy and Physiology, University of Melbourne, Parkville, VIC, Australia
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
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12
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Xu J, Wang M, Fu Y, Zhang C, Kuang Z, Bian S, Wan R, Qu S, Zhang C. Reversion of MRAP2 Protein Sequence Generates a Functional Novel Pharmacological Modulator for MC4R Signaling. BIOLOGY 2022; 11:biology11060874. [PMID: 35741395 PMCID: PMC9219869 DOI: 10.3390/biology11060874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 05/26/2022] [Accepted: 06/02/2022] [Indexed: 02/06/2023]
Abstract
Simple Summary Reversion of the wild-type protein sequences of single transmembrane melanocortin accessory protein families (MRAP2) in mice and zebrafish created novel functional pharmacological modulators for regulating melanocortin 4 receptor (MC4R) signaling. All of the brand new reversed MRAP2 (rMRAP2) proteins could form proper dimeric topology on the plasma membrane and interact with and affect the ligand-stimulated pharmacological profiles of zebrafish and mouse MC4R signaling in vitro. Abstract As a member of the melanocortin receptor family, melanocortin 4 receptor (MC4R) plays a critical role in regulating energy homeostasis and feeding behavior, and has been proven as a promising therapeutic target for treating severe obesity syndrome. Numerous studies have demonstrated that central MC4R signaling is significantly affected by melanocortin receptor accessory protein 2 (MRAP2) in humans, mice and zebrafish. MRAP2 proteins exist as parallel or antiparallel dimers on the plasma membrane, but the structural insight of dual orientations with the pharmacological profiles has not yet been fully studied. Investigation and optimization of the conformational topology of MRAP2 are critical for the development of transmembrane allosteric modulators to treat MC4R-associated disorders. In this study, we synthesized a brand new single transmembrane protein by reversing wild-type mouse and zebrafish MRAP2 sequences and examined their dimerization, interaction and pharmacological activities on mouse and zebrafish MC4R signaling. We showed that the reversed zebrafish MRAPa exhibited an opposite function on modulating zMC4R signaling and the reversed mouse MRAP2 lost the capability for regulating MC4R trafficking but exhibited a novel function for cAMP cascades, despite proper expression and folding. Taken together, our results provided new biochemical insights on the oligomeric states and membrane orientations of MRAP2 proteins, as well as its pharmacological assistance for modulating MC4R signaling.
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Affiliation(s)
- Jing Xu
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai 201619, China; (J.X.); (Y.F.); (C.Z.); (Z.K.)
| | - Meng Wang
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China;
| | - Yanbin Fu
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai 201619, China; (J.X.); (Y.F.); (C.Z.); (Z.K.)
| | - Cong Zhang
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai 201619, China; (J.X.); (Y.F.); (C.Z.); (Z.K.)
| | - Zhe Kuang
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai 201619, China; (J.X.); (Y.F.); (C.Z.); (Z.K.)
| | - Shan Bian
- Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200120, China;
| | - Rui Wan
- Department of Critical Care Medicine, Naval Medical Center of PLA, Shanghai 200052, China
- Correspondence: (R.W.); (S.Q.); (C.Z.)
| | - Shen Qu
- Department of Endocrinology and Metabolism, National Metabolic Management Center, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai 200072, China
- Correspondence: (R.W.); (S.Q.); (C.Z.)
| | - Chao Zhang
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai 201619, China; (J.X.); (Y.F.); (C.Z.); (Z.K.)
- Correspondence: (R.W.); (S.Q.); (C.Z.)
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13
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Rouault AAJ, Buscaglia P, Sebag JA. MRAP2 inhibits β-arrestin recruitment to the ghrelin receptor by preventing GHSR1a phosphorylation. J Biol Chem 2022; 298:102057. [PMID: 35605660 PMCID: PMC9190059 DOI: 10.1016/j.jbc.2022.102057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 11/19/2022] Open
Abstract
The melanocortin receptor accessory protein 2 (MRAP2) is essential for several physiological functions of the ghrelin receptor growth hormone secretagogue receptor 1a (GHSR1a), including increasing appetite and suppressing insulin secretion. In the absence of MRAP2, GHSR1a displays high constitutive activity and a weak G-protein-mediated response to ghrelin and readily recruits β-arrestin. In the presence of MRAP2, however, G-protein-mediated signaling via GHSR1a is strongly dependent on ghrelin stimulation and the recruitment of β-arrestin is significantly diminished. To better understand how MRAP2 modifies GHSR1a signaling, here we investigated the role of several phosphorylation sites within the C-terminal tail and third intracellular loop of GHSR1a, as well as the mechanism behind MRAP2-mediated inhibition of β-arrestin recruitment. We show that Ser252 and Thr261 in the third intracellular loop of GHSR1a contribute to β-arrestin recruitment, whereas the C-terminal region is not essential for β-arrestin interaction. Additionally, we found that MRAP2 inhibits GHSR1a phosphorylation by blocking the interaction of GRK2 and PKC with the receptor. Taken together, these data suggest that MRAP2 alters GHSR1a signaling by directly impacting the phosphorylation state of the receptor and that the C-terminal tail of GHSR1a prevents rather than contribute to β-arrestin recruitment.
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Affiliation(s)
- Alix A J Rouault
- Department of Molecular Physiology and Biophysics, University of Iowa, Carver College of Medicine, Iowa City, Iowa, USA; F.O.E.D.R.C, Iowa City, Iowa, USA; Pappajohn Biomedical Institute, Iowa City, Iowa, USA; Iowa Neuroscience Institute, Iowa City, Iowa, USA
| | - Paul Buscaglia
- Department of Molecular Physiology and Biophysics, University of Iowa, Carver College of Medicine, Iowa City, Iowa, USA; F.O.E.D.R.C, Iowa City, Iowa, USA; Pappajohn Biomedical Institute, Iowa City, Iowa, USA; Iowa Neuroscience Institute, Iowa City, Iowa, USA
| | - Julien A Sebag
- Department of Molecular Physiology and Biophysics, University of Iowa, Carver College of Medicine, Iowa City, Iowa, USA; F.O.E.D.R.C, Iowa City, Iowa, USA; Pappajohn Biomedical Institute, Iowa City, Iowa, USA; Iowa Neuroscience Institute, Iowa City, Iowa, USA.
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14
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Giorgioni G, Del Bello F, Quaglia W, Botticelli L, Cifani C, Micioni Di Bonaventura E, Micioni Di Bonaventura MV, Piergentili A. Advances in the Development of Nonpeptide Small Molecules Targeting Ghrelin Receptor. J Med Chem 2022; 65:3098-3118. [PMID: 35157454 PMCID: PMC8883476 DOI: 10.1021/acs.jmedchem.1c02191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ghrelin is an octanoylated peptide acting by the activation of the growth hormone secretagogue receptor, namely, GHS-R1a. The involvement of ghrelin in several physiological processes, including stimulation of food intake, gastric emptying, body energy balance, glucose homeostasis, reduction of insulin secretion, and lipogenesis validates the considerable interest in GHS-R1a as a promising target for the treatment of numerous disorders. Over the years, several GHS-R1a ligands have been identified and some of them have been extensively studied in clinical trials. The recently resolved structures of GHS-R1a bound to ghrelin or potent ligands have provided useful information for the design of new GHS-R1a drugs. This perspective is focused on the development of recent nonpeptide small molecules acting as GHS-R1a agonists, antagonists, and inverse agonists, bearing classical or new molecular scaffolds, as well as on radiolabeled GHS-R1a ligands developed for imaging. Moreover, the pharmacological effects of the most studied ligands have been discussed.
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Affiliation(s)
- Gianfabio Giorgioni
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, Via Madonna delle Carceri, 62032 Camerino, Italy
| | - Fabio Del Bello
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, Via Madonna delle Carceri, 62032 Camerino, Italy
| | - Wilma Quaglia
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, Via Madonna delle Carceri, 62032 Camerino, Italy
| | - Luca Botticelli
- School of Pharmacy, Pharmacology Unit, University of Camerino, Via Madonna delle Carceri 9, 62032 Camerino, Italy
| | - Carlo Cifani
- School of Pharmacy, Pharmacology Unit, University of Camerino, Via Madonna delle Carceri 9, 62032 Camerino, Italy
| | - E Micioni Di Bonaventura
- School of Pharmacy, Pharmacology Unit, University of Camerino, Via Madonna delle Carceri 9, 62032 Camerino, Italy
| | - M V Micioni Di Bonaventura
- School of Pharmacy, Pharmacology Unit, University of Camerino, Via Madonna delle Carceri 9, 62032 Camerino, Italy
| | - Alessandro Piergentili
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, Via Madonna delle Carceri, 62032 Camerino, Italy
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15
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Yu H, Rubinstein M, Low MJ. Developmental single-cell transcriptomics of hypothalamic POMC neurons reveal the genetic trajectories of multiple neuropeptidergic phenotypes. eLife 2022; 11:e72883. [PMID: 35044906 PMCID: PMC8806186 DOI: 10.7554/elife.72883] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 01/18/2022] [Indexed: 11/21/2022] Open
Abstract
Proopiomelanocortin (POMC) neurons of the hypothalamic arcuate nucleus are essential to regulate food intake and energy balance. However, the ontogenetic transcriptional programs that specify the identity and functioning of these neurons are poorly understood. Here, we use single-cell RNA-sequencing (scRNA-seq) to define the transcriptomes characterizing Pomc-expressing cells in the developing hypothalamus and translating ribosome affinity purification with RNA-sequencing (TRAP-seq) to analyze the subsequent translatomes of mature POMC neurons. Our data showed that Pomc-expressing neurons give rise to multiple developmental pathways expressing different levels of Pomc and unique combinations of transcription factors. The predominant cluster, featured by high levels of Pomc and Prdm12 transcripts, represents the canonical arcuate POMC neurons. Additional cell clusters expressing medium or low levels of Pomc mature into different neuronal phenotypes featured by distinct sets of transcription factors, neuropeptides, processing enzymes, cell surface, and nuclear receptors. We conclude that the genetic programs specifying the identity and differentiation of arcuate POMC neurons are diverse and generate a heterogeneous repertoire of neuronal phenotypes early in development that continue to mature postnatally.
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Affiliation(s)
- Hui Yu
- Department of Molecular and Integrative Physiology, University of Michigan Medical SchoolAnn ArborUnited States
| | - Marcelo Rubinstein
- Department of Molecular and Integrative Physiology, University of Michigan Medical SchoolAnn ArborUnited States
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y TécnicasBuenos AiresArgentina
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresBuenos AiresArgentina
| | - Malcolm J Low
- Department of Molecular and Integrative Physiology, University of Michigan Medical SchoolAnn ArborUnited States
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16
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Wang M, Xu J, Lei XW, Zhang C, Liu SY, Jin LN, Zhang C. Selective Interactions of Mouse Melanocortin Receptor Accessory Proteins with Somatostatin Receptors. Cells 2022; 11:cells11020267. [PMID: 35053382 PMCID: PMC8773839 DOI: 10.3390/cells11020267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/28/2021] [Accepted: 01/06/2022] [Indexed: 02/05/2023] Open
Abstract
Somatostatin receptors (SSTRs) are G protein-coupled receptors (GPCRs) known to regulate exocrine secretion, neurotransmission, and inhibit endogenous cell proliferation. SSTR subtypes (SSTR1-SSTR5) exhibit homo- or heterodimerization with unique signaling characteristics. Melanocortin receptor accessory protein 1 (MRAP1) functions as an allosteric modulator of melanocortin receptors and some other GPCRs. In this study, we investigated the differential interaction of MRAP1 and SSTRs and examined the pharmacological modulation of MRAP1 on mouse SSTR2/SSTR3 and SSTR2/SSTR5 heterodimerization in vitro. Our results show that the mouse SSTR2 forms heterodimers with SSTR3 and SSTR5 and that MRAP1 selectively interacts with SSTR3 and SSTR5 but not SSTR2. The interactive binding sites of SSTR2/SSTR3 or SSTR2/SSTR5 with MRAP1 locate on SSTR3 and SSTR5 but not SSTR2. The binding sites of MRAP1 to SSTR3 are extensive, while the ones of SSTR5 are restricted on transmembrane region six and seven. The heterodimerization of mouse SSTR2, SSTR3, and SSTR5 can be modulated by binding protein in addition to an agonist. Upregulation of extracellular signal-regulated kinases phosphorylation, p27Kip1, and increased cell growth inhibition with the co-expression of SSTR2/SSTR3 or SSTR2/SSTR5 with MRAP1 suggest a regulatory effect of MRAP1 on anti-proliferative response of two SSTR heterodimers. Taken together, these results provide a new insight of MRAP1 on the maintenance and regulation of mouse SSTR dimers which might be helpful to better understand the molecular mechanism involving SSTRs in tumor biology or other human disorders.
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Affiliation(s)
- Meng Wang
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai 201619, China; (M.W.); (J.X.); (X.-W.L.)
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China;
| | - Jing Xu
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai 201619, China; (M.W.); (J.X.); (X.-W.L.)
| | - Xiao-Wei Lei
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai 201619, China; (M.W.); (J.X.); (X.-W.L.)
| | - Cong Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China;
| | - Shang-Yun Liu
- Department of Hematology, Changzheng Hospital, Naval Medical University, Shanghai 200041, China;
| | - Li-Na Jin
- Department of Hematology, Changzheng Hospital, Naval Medical University, Shanghai 200041, China;
- Correspondence: (L.-N.J.); (C.Z.)
| | - Chao Zhang
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai 201619, China; (M.W.); (J.X.); (X.-W.L.)
- Correspondence: (L.-N.J.); (C.Z.)
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17
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Wang M, Zhai Y, Lei X, Xu J, Jiang B, Kuang Z, Zhang C, Liu S, Bian S, Yang XM, Zan T, Jin LN, Li Q, Zhang C. Determination of the Interaction and Pharmacological Modulation of MCHR1 Signaling by the C-Terminus of MRAP2 Protein. Front Endocrinol (Lausanne) 2022; 13:848728. [PMID: 35311242 PMCID: PMC8931191 DOI: 10.3389/fendo.2022.848728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 02/07/2022] [Indexed: 11/15/2022] Open
Abstract
Melanin concentrating hormone (MCH), an orexigenic neuropeptide, is primarily secreted by the hypothalamus and acts on its receptor, the melanin-concentrating hormone receptor 1 (MCHR1), to regulate appetite and energy homeostasis. The Melanocortin Receptor Accessory Protein 2 (MRAP2), a small single transmembrane protein broadly expressed in multiple tissues, has been defined as a vital endocrine modulator of five melanocortin receptors (MC1R-MC5R) and several other GPCRs in the regulation of central neuronal activities and peripheral energy balance. Here, we demonstrated the interaction between MRAP2 and MCHR1 by immunoprecipitation and bimolecular fluorescent assay and found that MRAP2 could inhibit MCHR1 signaling in vitro. A series of functional truncations of different regions further identified that the C-terminal domains of MRAP2 protein were required for the pharmacological modulation of intracellular Ca2+ coupled cascades and membrane transport. These findings elucidated the broad regulatory profile of MRAP2 protein in the central nervous system and may provide implications for the modulation of central MCHR1 function in vivo.
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Affiliation(s)
- Meng Wang
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yue Zhai
- Fundamental Research Center, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xiaowei Lei
- Fundamental Research Center, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jing Xu
- Fundamental Research Center, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Bopei Jiang
- Fundamental Research Center, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Zhe Kuang
- Fundamental Research Center, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Cong Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shangyun Liu
- Department of Hematology, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Shan Bian
- Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xiao-Mei Yang
- Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Tao Zan
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- *Correspondence: Tao Zan, ; Li-Na Jin, ; Qingfeng Li, ; Chao Zhang,
| | - Li-Na Jin
- Department of Hematology, Changzheng Hospital, Naval Medical University, Shanghai, China
- *Correspondence: Tao Zan, ; Li-Na Jin, ; Qingfeng Li, ; Chao Zhang,
| | - Qingfeng Li
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- *Correspondence: Tao Zan, ; Li-Na Jin, ; Qingfeng Li, ; Chao Zhang,
| | - Chao Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- *Correspondence: Tao Zan, ; Li-Na Jin, ; Qingfeng Li, ; Chao Zhang,
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18
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Price ML, Ley CD, Gorvin CM. The emerging role of heterodimerisation and interacting proteins in ghrelin receptor function. J Endocrinol 2021; 252:R23-R39. [PMID: 34663757 PMCID: PMC8630777 DOI: 10.1530/joe-21-0206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 10/18/2021] [Indexed: 11/14/2022]
Abstract
Ghrelin is a peptide hormone secreted primarily by the stomach that acts upon the growth hormone secretagogue receptor (GHSR1), a G protein-coupled receptor whose functions include growth hormone secretion, appetite regulation, energy expenditure, regulation of adiposity, and insulin release. Following the discovery that GHSR1a stimulates food intake, receptor antagonists were developed as potential therapies to regulate appetite. However, despite reductions in signalling, the desired effects on appetite were absent. Studies in the past 15 years have demonstrated GHSR1a can interact with other transmembrane proteins, either by direct binding (i.e. heteromerisation) or via signalling cross-talk. These interactions have various effects on GHSR1a signalling including preferential coupling to one pathway (i.e. biased signalling), coupling to a unique G protein (G protein switching), suppression of GHSR1a signalling, and enhancement of signalling by both receptors. While many of these interactions have been shown in cells overexpressing the proteins of interest and remain to be verified in tissues, substantial evidence exists showing that GHSR1a and the dopamine receptor D1 (DRD1) form heteromers, which promote synaptic plasticity and formation of hippocampal memory. Additionally, a reduction in GHSR1a-DRD1 complexes in favour of establishment of GHSR1a-Aβ complexes correlates with Alzheimer's disease, indicating that GHSR1a heteromers may have pathological functions. Herein, we summarise the evidence published to date describing interactions between GHSR1a and transmembrane proteins, discuss the experimental strengths and limitations of these studies, describe the physiological evidence for each interaction, and address their potential as novel drug targets for appetite regulation, Alzheimer's disease, insulin secretion, and inflammation.
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Affiliation(s)
- Maria L Price
- Institute of Metabolism and Systems Research and Centre for Endocrinology, Diabetes and Metabolism, University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Birmingham, UK
| | - Cameron D Ley
- Institute of Metabolism and Systems Research and Centre for Endocrinology, Diabetes and Metabolism, University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Birmingham, UK
| | - Caroline M Gorvin
- Institute of Metabolism and Systems Research and Centre for Endocrinology, Diabetes and Metabolism, University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Birmingham, UK
- Correspondence should be addressed to C M Gorvin:
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19
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Liu H, Sun D, Myasnikov A, Damian M, Baneres JL, Sun J, Zhang C. Structural basis of human ghrelin receptor signaling by ghrelin and the synthetic agonist ibutamoren. Nat Commun 2021; 12:6410. [PMID: 34737341 PMCID: PMC8568970 DOI: 10.1038/s41467-021-26735-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/14/2021] [Indexed: 12/26/2022] Open
Abstract
The hunger hormone ghrelin activates the ghrelin receptor GHSR to stimulate food intake and growth hormone secretion and regulate reward signaling. Acylation of ghrelin at Ser3 is required for its agonistic action on GHSR. Synthetic agonists of GHSR are under clinical evaluation for disorders related to appetite and growth hormone dysregulation. Here, we report high-resolution cryo-EM structures of the GHSR-Gi signaling complex with ghrelin and the non-peptide agonist ibutamoren as an investigational new drug. Our structures together with mutagenesis data reveal the molecular basis for the binding of ghrelin and ibutamoren. Structural comparison suggests a salt bridge and an aromatic cluster near the agonist-binding pocket as important structural motifs in receptor activation. Notable structural variations of the Gi and GHSR coupling are observed in our cryo-EM analysis. Our results provide a framework for understanding GHSR signaling and developing new GHSR agonist drugs.
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Affiliation(s)
- Heng Liu
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Dapeng Sun
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Alexander Myasnikov
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38120, USA
| | - Marjorie Damian
- Institut des Biomolécules Max Mousseron, CNRS, Université de Montpellier, ENSCM, Montpellier, France
| | - Jean-Louis Baneres
- Institut des Biomolécules Max Mousseron, CNRS, Université de Montpellier, ENSCM, Montpellier, France
| | - Ji Sun
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38120, USA.
| | - Cheng Zhang
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
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20
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Airapetov MI, Eresko SO, Lebedev AA, Bychkov ER, Shabanov PD. Expression of the growth hormone secretagogue receptor 1a (GHS-R1a) in the brain. Physiol Rep 2021; 9:e15113. [PMID: 34755494 PMCID: PMC8578894 DOI: 10.14814/phy2.15113] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/23/2021] [Accepted: 10/26/2021] [Indexed: 12/17/2022] Open
Abstract
The review presents data on the expression of growth hormone secretagogue receptor 1a (GHS-R1a) in the brain regions in model animals (zebrafish, rodents, primates), and in the human brain. Studies show widespread distribution of the receptor in the brain, which evidences the involvement of the receptor in many physiological processes. Using various organisms, data have been obtained regarding the participation of the GHS-R1a in the regulation of the anti- and pro-inflammatory response, proliferation, and apoptosis. It is known that the receptor plays an important role in eating behavior and is also involved in the pathogenetic mechanisms of drug addiction, obesity, and chronic alcohol consumption. Based on this, research is underway with the use of various therapeutic agents that can be used for the pharmacological correction of these conditions. This review also presents hypothetical pathways of intracellular signaling, in which GHS-R1a may participate. A complete understanding of these mechanisms has not yet been reached. The ghrelin intracellular signaling seem to be specific to brain region and, probably, also depend on the metabolic or stress status of the organism.
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Affiliation(s)
- Marat I. Airapetov
- Department of NeuropharmacologyInstitute of Experimental MedicineSt. PetersburgRussia
- Department of PharmacologySt. Petersburg State Pediatric Medical UniversitySt. PetersburgRussia
| | - Sergei O. Eresko
- Department of NeuropharmacologyInstitute of Experimental MedicineSt. PetersburgRussia
- Research and Training Center of Molecular and Cellular TechnologiesSt. Petersburg State Chemical Pharmaceutical UniversitySt PetersburgRussia
- Department of BiologySaint‐Petersburg State UniversitySt PetersburgRussia
| | - Andrei A. Lebedev
- Department of NeuropharmacologyInstitute of Experimental MedicineSt. PetersburgRussia
| | - Evgenii R. Bychkov
- Department of NeuropharmacologyInstitute of Experimental MedicineSt. PetersburgRussia
- Department of PharmacologyKirov Military Medical AcademySt. PetersburgRussia
| | - Petr D. Shabanov
- Department of NeuropharmacologyInstitute of Experimental MedicineSt. PetersburgRussia
- Department of PharmacologyKirov Military Medical AcademySt. PetersburgRussia
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21
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Verdinez JA, Sebag JA. Role of N-Linked Glycosylation in PKR2 Trafficking and Signaling. Front Neurosci 2021; 15:730417. [PMID: 34483834 PMCID: PMC8414166 DOI: 10.3389/fnins.2021.730417] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 07/27/2021] [Indexed: 12/26/2022] Open
Abstract
Prokineticin receptors are GPCRs involved in several physiological processes including the regulation of energy homeostasis, nociception, and reproductive function. PKRs are inhibited by the endogenous accessory protein MRAP2 which prevents them from trafficking to the plasma membrane. Very little is known about the importance of post-translational modification of PKRs and their role in receptor trafficking and signaling. Here we identify 2 N-linked glycosylation sites within the N-terminal region of PKR2 and demonstrate that glycosylation of PKR2 at position 27 is important for its plasma membrane localization and signaling. Additionally, we show that glycosylation at position 7 results in a decrease in PKR2 signaling through Gαs without impairing Gαq/11 signaling.
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Affiliation(s)
- Jissele A Verdinez
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA, United States.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, United States.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
| | - Julien A Sebag
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA, United States.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, United States.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
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22
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Airapetov MI, Eresko SO, Lebedev AA, Bychkov ER, Shabanov PD. Expression of Ghrelin Receptor GHS-R1a in the Brain (Mini Review). Mol Biol 2021. [DOI: 10.1134/s002689332103002x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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23
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Jabbari S, Bananej M, Zarei M, Komaki A, Hajikhani R. Effects of intrathecal and intracerebroventricular microinjection of kaempferol on pain: possible mechanisms of action. Res Pharm Sci 2021; 16:203-216. [PMID: 34084207 PMCID: PMC8102926 DOI: 10.4103/1735-5362.310527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/19/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023] Open
Abstract
Background and purpose: Kaempferol (KM), a flavonoid, has an anti-inflammatory and anticancer effect and prevents many metabolic diseases. Nonetheless, very few studies have been done on the antinociceptive effects of KM. This research aimed at assessing the involvement of opioids, gamma-aminobutyric acid (GABA) receptors, and inflammatory mediators in the antinociceptive effects of KM in male Wistar rats. Experimental approach: The intracerebroventricular and/or intrathecal administration of the compounds was done for examining their central impacts on the thermal and chemical pain by the tail-flick and formalin paw tests. For assessing the role of opioid and GABA receptors in the possible antinociceptive effects of KM, several antagonists were used. Also, a rotarod test was carried out for assessing motor performance. Findings/Results: The intracerebroventricular and/or intrathecal microinjections of KM (40 μg/rat) had partially antinociceptive effects in the tail-flick test in rats (P < 0.05). In the formalin paw model, the intrathecal microinjection of KM had antinociceptive effects in phase 1 (20 and 40 μg/rat; P < 0.05 and P < 0.01, respectively) and phase 2 (20 and 40 μg/rat; P < 0.01 and P < 0.001, respectively). Using naloxonazine and/or bicuculline approved the involvement of opioid and GABA receptors in the central antinociceptive effects of KM, respectively. Moreover, KM reduced the expression levels of caspase 6, interleukin-1β, tumor necrosis factor-α, and interleukin-6. The antinociceptive effects of KM were not linked to variations in the locomotor activity. Conclusion and implications: It can be concluded that KM has remarkable antinociceptive effects at a spinal level, which is associated with the presence of the inflammatory state. These impacts were undetectable following injections in the lateral ventricle. The possible mechanisms of KM antinociception are possibly linked to various modulatory pathways, including opioid and GABA receptors.
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Affiliation(s)
- Sajjad Jabbari
- Department of Biology, Faculty of Sciences, Islamic Azad University, Tehran North Branch, Tehran, Iran
| | - Maryam Bananej
- Department of Biology, Faculty of Sciences, Islamic Azad University, Tehran North Branch, Tehran, Iran
| | - Mohammad Zarei
- Department of Physiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.,Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Alireza Komaki
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Ramin Hajikhani
- Department of Biology, Faculty of Sciences, Islamic Azad University, Tehran North Branch, Tehran, Iran
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24
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Chang CH, Liu YC, Sun CY, Su CL, Gean PW. Regulation of stress-provoked aggressive behavior using endocannabinoids. Neurobiol Stress 2021; 15:100337. [PMID: 34041309 PMCID: PMC8144478 DOI: 10.1016/j.ynstr.2021.100337] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 05/02/2021] [Accepted: 05/06/2021] [Indexed: 11/17/2022] Open
Abstract
Reactive impulsive aggression is characterized by outbursts of rage and violence when subjects encounter threatening stressful events. Although impulsive aggression and violence create a high-cost burden on health and society, relatively little is known about treatment. Early adolescent social isolation (SI) alters brain development and functions. It induces hyper-excitatory in the ventral hippocampus (vHip) to promote acute stress-provoked outbursts of aggression, referred to as impulsive aggression, in mouse models. Cannabinoid type 1 receptors (CB1Rs) act on presynaptic sites and suppress neurotransmitter release into synapses. Given that CB1R activation inhibits neurotransmitter releases and modulates excitatory network activity, we tested the hypothesis that CB1R activation reduces impulsive aggression in SI mice through decreasing excitatory activity in the vHip. Here, we report that CB1R agonists, WIN-552122 (WIN) or arachidonylcyclopropylamide (ACPA), ameliorated acute stress-provoked attack behavior in the resident-intruder test without affecting general locomotion activity. Increasing endocannabinoids (eCBs) by inhibiting degradation enzymes in the vHip reduced impulsive aggression, and the effect was blunted by administration of AM251, a CB1R antagonist. Acute stress in SI mice induced c-Fos expression, a marker of neuronal activation, on vHip neurons projecting to the ventromedial hypothalamus (VMH), a well-known brain area that controls attack behavior. eCB augmentation inhibited c-Fos expression in VMH-projecting vHip neurons surrounded by CB1Rs. These results suggest that enhancing eCB signaling in order to activate CB1Rs suppresses impulsive aggression via suppressing vHip→VMH neural activity and point to a role of CB1R activation in ameliorating impulsive aggression in adults who have had adverse experiences during early adolescence. Early adolescent social isolation (SI) promotes impulsive aggression. Treatment of CB1R agonists reduces impulsive aggression in SI mice. Increasing endocannabinoids (eCBs) to activate CB1Rs reduces impulsive aggression. Augmenting eCBs suppresses stress-provoked neuronal activation in the hippocampus.
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Affiliation(s)
- Chih-Hua Chang
- Department of Pharmacology, National Cheng-Kung University, Tainan, Taiwan.,Department of Biotechnology and Bioindustry Sciences, National Cheng-Kung University, Tainan, 701, Taiwan
| | - Yu-Chen Liu
- Department of Pharmacology, National Cheng-Kung University, Tainan, Taiwan
| | - Chih-Yang Sun
- Department of Pharmacology, National Cheng-Kung University, Tainan, Taiwan
| | - Chun-Lin Su
- Division of Natural Sciences, Center for General Education, Southern Taiwan University of Science and Technology, Tainan, Taiwan
| | - Po-Wu Gean
- Department of Pharmacology, National Cheng-Kung University, Tainan, Taiwan.,Department of Biotechnology and Bioindustry Sciences, National Cheng-Kung University, Tainan, 701, Taiwan
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25
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Stoyanova I, Lutz D. Ghrelin-Mediated Regeneration and Plasticity After Nervous System Injury. Front Cell Dev Biol 2021; 9:595914. [PMID: 33869167 PMCID: PMC8046019 DOI: 10.3389/fcell.2021.595914] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 02/24/2021] [Indexed: 12/17/2022] Open
Abstract
The nervous system is highly vulnerable to different factors which may cause injury followed by an acute or chronic neurodegeneration. Injury involves a loss of extracellular matrix integrity, neuronal circuitry disintegration, and impairment of synaptic activity and plasticity. Application of pleiotropic molecules initiating extracellular matrix reorganization and stimulating neuronal plasticity could prevent propagation of the degeneration into the tissue surrounding the injury. To find an omnipotent therapeutic molecule, however, seems to be a fairly ambitious task, given the complex demands of the regenerating nervous system that need to be fulfilled. Among the vast number of candidates examined so far, the neuropeptide and hormone ghrelin holds within a very promising therapeutic potential with its ability to cross the blood-brain barrier, to balance metabolic processes, and to stimulate neurorepair and neuroactivity. Compared with its well-established systemic effects in treatment of metabolism-related disorders, the therapeutic potential of ghrelin on neuroregeneration upon injury has received lesser appreciation though. Here, we discuss emerging concepts of ghrelin as an omnipotent player unleashing developmentally related molecular cues and morphogenic cascades, which could attenuate and/or counteract acute and chronic neurodegeneration.
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Affiliation(s)
- Irina Stoyanova
- Department of Anatomy and Cell Biology, Medical University Varna, Varna, Bulgaria
| | - David Lutz
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany
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26
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Biased signaling: A viable strategy to drug ghrelin receptors for the treatment of obesity. Cell Signal 2021; 83:109976. [PMID: 33713808 DOI: 10.1016/j.cellsig.2021.109976] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/23/2021] [Accepted: 03/08/2021] [Indexed: 02/07/2023]
Abstract
Obesity is a global burden and a chronic ailment with damaging overall health effects. Ghrelin, an octanoylated 28 amino acid peptide hormone, is secreted from the oxyntic mucosa of the stomach. Ghrelin acts on regions of the hypothalamus to regulate feeding behavior and glucose homeostasis through its G protein-coupled receptor. Recently, several central pathways modulating the metabolic actions of ghrelin have been reported. While these signaling pathways can be inhibited or activated by antagonists or agonists, they can also be discriminatingly activated in a "biased" response to impart different degrees of activation in distinct pathways downstream of the receptor. Here, we review recent ghrelin biased signaling findings as well as characteristics of ghrelin hormone and its receptors pertinent for biased signaling. We then evaluate the feasibility for ghrelin receptor biased signaling as a strategy for the development of effective pharmacotherapy in obesity treatment.
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27
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Wang M, Zhai Y, Lu L, Zhang C, Li N, Xue S, Cheng D, Fu S, Liu Q, Zhang C. Elucidation of the dimeric interplay of dual MRAP2 proteins in the zebrafish. J Cell Physiol 2021; 236:6472-6480. [PMID: 33559170 DOI: 10.1002/jcp.30321] [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: 08/26/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 11/07/2022]
Abstract
The melanocortin receptor accessory protein 2 (MRAP2) plays an essential role in the regulation of metabolic homeostasis and deletion of which results in severe obesity syndrome in mice and human. Mammalian MRAP2 is recognized as an endogenous physiological mediator through the potentiation of the MC4R signaling in vivo. Two isoforms of MRAP2 are identified in zebrafish genome, zMRAP2a and zMRAP2b. However, the mechanism of assembling dual topology and the regulatory roles of each complex on the melanocortin cascades remains unclear. In this study, we showed the bidirectional homo- and hetero-dimeric topologies of two zebrafish MRAP2 isoforms on the plasma membrane. Orientation fixed chimeric proteins could affect the trafficking and pharmacological properties of zMC4R signaling. Reciprocal replacement of zMRAP2a and zMRAP2b proteins elucidated the major participation of the carboxyl terminal as the functional domain for modulating zMC4R signaling. Our findings revealed the complex and dynamic conformational regulation of dual zebrafish MRAP2 proteins in vitro.
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Affiliation(s)
- Meng Wang
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yue Zhai
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Liumei Lu
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Cong Zhang
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Na Li
- Yantai Derui Bio-Tech Co.,Ltd, Yantai, Shandong, China
| | - Song Xue
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Daofu Cheng
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Shaliu Fu
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Qi Liu
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Chao Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
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28
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Tai X, Xue S, Zhang C, Liu Y, Chen J, Han Y, Lin G, Zhang C. Pharmacological evaluation of MRAP proteins on Xenopus neural melanocortin signaling. J Cell Physiol 2021; 236:6344-6361. [PMID: 33521982 DOI: 10.1002/jcp.30306] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 01/13/2021] [Accepted: 01/20/2021] [Indexed: 12/14/2022]
Abstract
Melanocortin-3 receptor (MC3R) and melanocortin-4 receptor (MC4R), two neural G protein-coupled receptors are known to be functionally critical for energy balance in vertebrates. As allosteric regulators of melanocortin receptors, melanocortin accessory proteins (MRAPs) are also involved in energy homeostasis. The interaction of MRAPs and melanocortin signaling was previously shown in mammals and zebrafish, but nothing had been reported in amphibians. As the basal class of tetrapods, amphibians occupy a phylogenetic transition between teleosts and terrestrial animals. Here we examined the evolutionary conservation of MC3R, MC4R, and MRAPs between diploid Xenopus tropicalis (xt-) and other chordates and investigated the pharmacological regulatory properties of MRAPs on the neural MC3R and MC4R signaling. Our results showed that xtMRAP and xtMRAP2 both exerted robust potentiation effect on agonist (α-MSH and adrenocorticotropin [ACTH]) induced activation and modulated the basal activity and cell surface translocation of xtMC3R and xtMC4R. In addition, the presence of two accessory proteins could convert xtMC3R and xtMC4R into ACTH-preferred receptors. These findings suggest that the presence of MRAPs exhibits fine control over the pharmacological activities of the neuronal MC3R and MC4R signaling in the Xenopus tropicalis, which is physiologically relevant with the complicated transition of feeding behaviors during their life history.
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Affiliation(s)
- Xiaolu Tai
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Song Xue
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Cong Zhang
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Yu Liu
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jie Chen
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Yu Han
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Gufa Lin
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Chao Zhang
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
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29
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Cornejo MP, Mustafá ER, Cassano D, Banères JL, Raingo J, Perello M. The ups and downs of growth hormone secretagogue receptor signaling. FEBS J 2021; 288:7213-7229. [PMID: 33460513 DOI: 10.1111/febs.15718] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/05/2021] [Accepted: 01/14/2021] [Indexed: 12/14/2022]
Abstract
The growth hormone secretagogue receptor (GHSR) has emerged as one of the most fascinating molecules from the perspective of neuroendocrine control. GHSR is mainly expressed in the pituitary and the brain, and plays key roles regulating not only growth hormone secretion but also food intake, adiposity, body weight, glucose homeostasis and other complex functions. Quite atypically, GHSR signaling displays a basal constitutive activity that can be up- or downregulated by two digestive system-derived hormones: the octanoylated-peptide ghrelin and the liver-expressed antimicrobial peptide 2 (LEAP2), which was recently recognized as an endogenous GHSR ligand. The existence of two ligands with contrary actions indicates that GHSR activity can be tightly regulated and that the receptor displays the capability to integrate such opposing inputs in order to provide a balanced intracellular signal. This article provides a summary of the current understanding of the biology of ghrelin, LEAP2 and GHSR and discusses the reconceptualization of the cellular and physiological implications of the ligand-regulated GHSR signaling, based on the latest findings.
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Affiliation(s)
- María P Cornejo
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET), Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], Buenos Aires, Argentina
| | - Emilio R Mustafá
- Laboratory of Electrophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET), Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], Buenos Aires, Argentina
| | - Daniela Cassano
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET), Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], Buenos Aires, Argentina
| | - Jean-Louis Banères
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, Faculté de Pharmacie, Montpellier cedex 5, France
| | - Jesica Raingo
- Laboratory of Electrophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET), Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], Buenos Aires, Argentina
| | - Mario Perello
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET), Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], Buenos Aires, Argentina
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30
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Xiao X, Bi M, Jiao Q, Chen X, Du X, Jiang H. A new understanding of GHSR1a--independent of ghrelin activation. Ageing Res Rev 2020; 64:101187. [PMID: 33007437 DOI: 10.1016/j.arr.2020.101187] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/13/2020] [Accepted: 09/21/2020] [Indexed: 12/13/2022]
Abstract
Growth hormone secretagogue receptor 1a (GHSR1a), a member of the G protein-coupled receptor (GPCR) family, is a functional receptor of ghrelin. The expression levels and activities of GHSR1a are affected by various factors. In past years, it has been found that the ghrelin-GHSR1a system can perform biological functions such as anti-inflammation, anti-apoptosis, and anti-oxidative stress. In addition to mediating the effect of ghrelin, GHSR1a also has abnormally high constitutive activity; that is, it can still transmit intracellular signals without activation of the ghrelin ligand. This constitutive activity affects brain functions, growth and development of the body; therefore, it has profound impacts on neurodegenerative diseases and some other age-related diseases. In addition, GHSR1a can also form homodimers or heterodimers with other GPCRs, affecting the release of neurotransmitters, appetite regulation, cell proliferation and insulin release. Therefore, further understanding of the constitutive activities and dimerization of GHSR1a will enable us to better clarify the characteristics of GHSR1a and provide more therapeutic targets for drug development. Here, we focus on the roles of GHSR1a in various biological functions and provide a comprehensive summary of the current research on GHSR1a to provide broader therapeutic prospects for age-related disease treatment.
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Affiliation(s)
- Xue Xiao
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Mingxia Bi
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Qian Jiao
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Xi Chen
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Xixun Du
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Qingdao University, Qingdao, China.
| | - Hong Jiang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Qingdao University, Qingdao, China.
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31
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"A LEAP 2 conclusions? Targeting the ghrelin system to treat obesity and diabetes". Mol Metab 2020; 46:101128. [PMID: 33246141 PMCID: PMC8085568 DOI: 10.1016/j.molmet.2020.101128] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/15/2020] [Accepted: 11/20/2020] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND The hormone ghrelin stimulates food intake, promotes adiposity, increases body weight, and elevates blood glucose. Consequently, alterations in plasma ghrelin levels and the functioning of other components of the broader ghrelin system have been proposed as potential contributors to obesity and diabetes. Furthermore, targeting the ghrelin system has been proposed as a novel therapeutic strategy for obesity and diabetes. SCOPE OF REVIEW The current review focuses on the potential for targeting ghrelin and other proteins comprising the ghrelin system as a treatment for obesity and diabetes. The main components of the ghrelin system are introduced. Data supporting a role for the endogenous ghrelin system in the development of obesity and diabetes along with data that seemingly refute such a role are outlined. An argument for further research into the development of ghrelin system-targeted therapeutic agents is delineated. Also, an evidence-based discussion of potential factors and contexts that might influence the efficacy of this class of therapeutics is provided. MAJOR CONCLUSIONS It would not be a "leap to" conclusions to suggest that agents which target the ghrelin system - including those that lower acyl-ghrelin levels, raise LEAP2 levels, block GHSR activity, and/or raise desacyl-ghrelin signaling - could represent efficacious novel treatments for obesity and diabetes.
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32
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Cornejo MP, Mustafá ER, Barrile F, Cassano D, De Francesco PN, Raingo J, Perello M. THE INTRIGUING LIGAND-DEPENDENT AND LIGAND-INDEPENDENT ACTIONS OF THE GROWTH HORMONE SECRETAGOGUE RECEPTOR ON REWARD-RELATED BEHAVIORS. Neurosci Biobehav Rev 2020; 120:401-416. [PMID: 33157147 DOI: 10.1016/j.neubiorev.2020.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/18/2020] [Accepted: 10/20/2020] [Indexed: 02/07/2023]
Abstract
The growth hormone secretagogue receptor (GHSR) is a G-protein-coupled receptor (GPCR) highly expressed in the brain, and also in some peripheral tissues. GHSR activity is evoked by the stomach-derived peptide hormone ghrelin and abrogated by the intestine-derived liver-expressed antimicrobial peptide 2 (LEAP2). In vitro, GHSR displays ligand-independent actions, including a high constitutive activity and an allosteric modulation of other GPCRs. Beyond its neuroendocrine and metabolic effects, cumulative evidence shows that GHSR regulates the activity of the mesocorticolimbic pathway and modulates complex reward-related behaviors towards different stimuli. Here, we review current evidence indicating that ligand-dependent and ligand-independent actions of GHSR enhance reward-related behaviors towards appetitive stimuli and drugs of abuse. We discuss putative neuronal networks and molecular mechanisms that GHSR would engage to modulate such reward-related behaviors. Finally, we briefly discuss imaging studies showing that ghrelin would also regulate reward processing in humans. Overall, we conclude that GHSR is a key regulator of the mesocorticolimbic pathway that influences its activity and, consequently, modulates reward-related behaviors via ligand-dependent and ligand-independent actions.
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Affiliation(s)
- María P Cornejo
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA). National University of La Plata], 1900 La Plata, Buenos Aires, Argentina
| | - Emilio R Mustafá
- Laboratory of Electrophysiology of the IMBICE, 1900 La Plata, Buenos Aires, Argentina
| | - Franco Barrile
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA). National University of La Plata], 1900 La Plata, Buenos Aires, Argentina
| | - Daniela Cassano
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA). National University of La Plata], 1900 La Plata, Buenos Aires, Argentina
| | - Pablo N De Francesco
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA). National University of La Plata], 1900 La Plata, Buenos Aires, Argentina
| | - Jesica Raingo
- Laboratory of Electrophysiology of the IMBICE, 1900 La Plata, Buenos Aires, Argentina
| | - Mario Perello
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA). National University of La Plata], 1900 La Plata, Buenos Aires, Argentina.
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33
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Berruien NNA, Smith CL. Emerging roles of melanocortin receptor accessory proteins (MRAP and MRAP2) in physiology and pathophysiology. Gene 2020; 757:144949. [PMID: 32679290 DOI: 10.1016/j.gene.2020.144949] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 01/07/2023]
Abstract
Melanocortin-2 receptor accessory protein (MRAP) has an unusual dual topology and influences the expression, localisation, signalling and internalisation of the melanocortin receptor 2 (MC2); the adrenocorticotropic hormone (ACTH) receptor. Mutations in MRAP are associated with familial glucocorticoid deficiency type-2 and evidence is emerging of the importance of MRAP in adrenal development and ACTH signalling. Human MRAP has two functional splice variants: MRAP-α and MRAP-β, unlike MRAP-β, MRAP-α has little expression in brain but is highly expressed in ovary. MRAP2, identified through whole human genome sequence analysis, has approximately 40% sequence homology to MRAP. MRAP2 facilitates MC2 localisation to the cell surface but not ACTH signalling. MRAP and MRAP2 have been found to regulate the surface expression and signalling of all melanocortin receptors (MC1-5). Additionally, MRAP2 moderates the signalling of the G-protein coupled receptors (GCPRs): orexin, prokineticin and GHSR1a; the ghrelin receptor. Whilst MRAP appears to be mainly involved in glucocorticoid synthesis, an important role is emerging for MRAP2 in regulating appetite and energy homeostasis. Transgenic models indicate the importance of MRAP in adrenal gland formation. Like MC3R and MC4R knockout mice, MRAP2 knockout mice have an obese phenotype. In vitro studies indicate that MRAP2 enhances the MC3 and MC4 response to the agonist αMSH, which, like ACTH, is produced through precursor polypeptide proopiomelanocortin (POMC) cleavage. Analysis of cohorts of individuals with obesity have revealed several MRAP2 genetic variants with loss of function mutations which are causative of monogenic hyperphagic obesity with hyperglycaemia and hypertension. MRAP2 may also be associated with female infertility. This review summarises current knowledge of MRAP and MRAP2, their influence on GPCR signalling, and focusses on pathophysiology, particularly familial glucocorticoid deficiency type-2 and obesity.
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Affiliation(s)
- Nasrin N A Berruien
- School of Life Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK.
| | - Caroline L Smith
- School of Life Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK.
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Chen V, Bruno AE, Britt LL, Hernandez CC, Gimenez LE, Peisley A, Cone RD, Millhauser GL. Membrane orientation and oligomerization of the melanocortin receptor accessory protein 2. J Biol Chem 2020; 295:16370-16379. [PMID: 32943551 DOI: 10.1074/jbc.ra120.015482] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/08/2020] [Indexed: 12/12/2022] Open
Abstract
The melanocortin receptor accessory protein 2 (MRAP2) plays a pivotal role in the regulation of several G protein-coupled receptors that are essential for energy balance and food intake. MRAP2 loss-of-function results in obesity in mammals. MRAP2 and its homolog MRAP1 have an unusual membrane topology and are the only known eukaryotic proteins that thread into the membrane in both orientations. In this study, we demonstrate that the conserved polybasic motif that dictates the membrane topology and dimerization of MRAP1 does not control the membrane orientation and dimerization of MRAP2. We also show that MRAP2 dimerizes through its transmembrane domain and can form higher-order oligomers that arrange MRAP2 monomers in a parallel orientation. Investigating the molecular details of MRAP2 structure is essential for understanding the mechanism by which it regulates G protein-coupled receptors and will aid in elucidating the pathways involved in metabolic dysfunction.
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Affiliation(s)
- Valerie Chen
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California, USA
| | - Antonio E Bruno
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California, USA
| | - Laura L Britt
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California, USA
| | - Ciria C Hernandez
- Life Sciences Institute and Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Luis E Gimenez
- Life Sciences Institute and Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Alys Peisley
- Life Sciences Institute and Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Roger D Cone
- Life Sciences Institute and Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Glenn L Millhauser
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California, USA.
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Structural Complexity and Plasticity of Signaling Regulation at the Melanocortin-4 Receptor. Int J Mol Sci 2020; 21:ijms21165728. [PMID: 32785054 PMCID: PMC7460885 DOI: 10.3390/ijms21165728] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/03/2020] [Accepted: 08/06/2020] [Indexed: 02/06/2023] Open
Abstract
The melanocortin-4 receptor (MC4R) is a class A G protein-coupled receptor (GPCR), essential for regulation of appetite and metabolism. Pathogenic inactivating MC4R mutations are the most frequent cause of monogenic obesity, a growing medical and socioeconomic problem worldwide. The MC4R mediates either ligand-independent or ligand-dependent signaling. Agonists such as α-melanocyte-stimulating hormone (α-MSH) induce anorexigenic effects, in contrast to the endogenous inverse agonist agouti-related peptide (AgRP), which causes orexigenic effects by suppressing high basal signaling activity. Agonist action triggers the binding of different subtypes of G proteins and arrestins, leading to concomitant induction of diverse intracellular signaling cascades. An increasing number of experimental studies have unraveled molecular properties and mechanisms of MC4R signal transduction related to physiological and pathophysiological aspects. In addition, the MC4R crystal structure was recently determined at 2.75 Å resolution in an inactive state bound with a peptide antagonist. Underpinned by structural homology models of MC4R complexes simulating a presumably active-state conformation compared to the structure of the inactive state, we here briefly summarize the current understanding and key players involved in the MC4R switching process between different activity states. Finally, these perspectives highlight the complexity and plasticity in MC4R signaling regulation and identify gaps in our current knowledge.
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Tao YX. Molecular chaperones and G protein-coupled receptor maturation and pharmacology. Mol Cell Endocrinol 2020; 511:110862. [PMID: 32389798 DOI: 10.1016/j.mce.2020.110862] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 12/15/2022]
Abstract
G protein-coupled receptors (GPCRs) are highly conserved versatile signaling molecules located at the plasma membrane that respond to diverse extracellular signals. They regulate almost all physiological processes in the vertebrates. About 35% of current drugs target these receptors. Mutations in these genes have been identified as causes of numerous diseases. The seven transmembrane domain structure of GPCRs implies that the folding of these transmembrane proteins is extremely complicated and difficult. Indeed, many wild type GPCRs are not folded optimally. The most common defect in genetic diseases caused by GPCR mutations is misfolding and failure to reach the plasma membrane where it functions. General molecular chaperones aid the folding of all proteins, including GPCRs, by preventing aggregation, promoting folding and disaggregating small aggregates. Some GPCRs need additional receptor-specific chaperones to assist their folding. Many of these receptor-specific chaperones interact with additional receptors and alter receptor pharmacology, expanding the understanding of these chaperone proteins.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, 36849-5519, USA.
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Flees J, Greene E, Ganguly B, Dridi S. Phytogenic feed- and water-additives improve feed efficiency in broilers via modulation of (an)orexigenic hypothalamic neuropeptide expression. Neuropeptides 2020; 81:102005. [PMID: 31926603 DOI: 10.1016/j.npep.2020.102005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 12/17/2019] [Accepted: 01/02/2020] [Indexed: 12/12/2022]
Abstract
Fueled by consumer preference for natural and antibiotic-free products, phytogenics have become the fastest growing segment of the animal feed additives. Yet, their modes of action are not fully understood. This study was undertaken to determine the effect of 5 phytogenics (3 feed- and 2 water-supplements) on the growth performance of commercial broilers, and their potential underlying molecular mechanisms. Day-old male Cobb 500 chicks (n = 576) were randomly assigned into 48 pens consisting of 6 treatments (Control; AVHGP; SCP; BHGP; AVSSL; SG) in a complete randomized design (12 birds/pen, 8 pens/treatment, 96 birds/treatment). Chicks had ad libitum access to feed and water. Individual body weight (BW) was recorded weekly and feed intake was measured daily. Core body temperatures were continuously recorded using thermo-loggers. At d 35, hypothalamic tissues were excised from the thermo-logger-equipped chickens (n = 8 birds/treatment) to determine the expression of feeding-related neuropeptides. Both feed (AVHGP, SCP, BHGP) and water-supplemented (AVSSL, SG) phytogenics significantly improved feed efficiency (FE) compared to the control birds. This higher FE was achieved via a reduction in core body temperature and improvement of market BW, without changes in feed intake in broilers supplemented with phytogenic water additives as compared to the control group. Broilers fed dietary phytogenics, however, attained higher feed efficiency via a reduction in feed intake while maintaining similar BW as the control group. At the molecular levels, the effects of the phytogenic water additives seemed to be mediated by the activation of the hypothalamic AgRP-ORX-mTOR-S6k1 and inhibition of CRH pathways. The effect of the phytogenic feed additives appeared to be exerted through the activation of AdipoQ, STAT3, AMPK, and MC1R pathways. This is the first report describing the likely central mechanisms through which phytogenic additives improve the growth performance and feed efficiency in broilers.
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Affiliation(s)
- Joshua Flees
- Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, United States of America
| | - Elizabeth Greene
- Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, United States of America
| | - Bhaskar Ganguly
- Clinical Research, Ayurvet Limited, Baddi, Himachal Pradesh 173205, India
| | - Sami Dridi
- Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, United States of America.
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Yin TC, Bauchle CJ, Rouault AAJ, Stephens SB, Sebag JA. The Insulinostatic Effect of Ghrelin Requires MRAP2 Expression in δ Cells. iScience 2020; 23:101216. [PMID: 32535024 PMCID: PMC7300157 DOI: 10.1016/j.isci.2020.101216] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 04/07/2020] [Accepted: 05/26/2020] [Indexed: 02/01/2023] Open
Abstract
Ghrelin regulates both energy intake and glucose homeostasis. In the endocrine pancreas, ghrelin inhibits insulin release to prevent hypoglycemia during fasting. The mechanism through which this is accomplished is unclear, but recent studies suggest that ghrelin acts on δ cells to stimulate somatostatin release, which in turn inhibits insulin release from β cells. Recently, the Melanocortin Receptor Accessory Protein 2 (MRAP2) was identified as an essential partner of the ghrelin receptor (GHSR1a) in mediating the central orexigenic action of ghrelin. In this study we show that MRAP2 is expressed in islet δ cells and is required for ghrelin to elicit a calcium response in those cells. Additionally, we show that both global and δ cell targeted deletion of MRAP2 abrogates the insulinostatic effect of ghrelin. Together, these findings establish that ghrelin signaling within δ cells is essential for the inhibition of insulin release and identify MRAP2 as a regulator of insulin secretion. δ Cells are responsible for the action of ghrelin in the endocrine pancreas MRAP2 is expressed in multiple cell types in the endocrine pancreas including δ cells MRAP2 is required for GHSR1a signaling in δ cells Deletion of MRAP2 results in loss of ghrelin-mediated inhibition of insulin secretion
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Affiliation(s)
- Terry C Yin
- Department of Molecular Physiology and Biophysics, Fraternal Order of Eagle Diabetes Research Center, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Casey J Bauchle
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Fraternal Order of Eagle Diabetes Research Center, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Alix A J Rouault
- Department of Molecular Physiology and Biophysics, Fraternal Order of Eagle Diabetes Research Center, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Samuel B Stephens
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Fraternal Order of Eagle Diabetes Research Center, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Julien A Sebag
- Department of Molecular Physiology and Biophysics, Fraternal Order of Eagle Diabetes Research Center, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA.
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Zhan H, Zhang S, Zhang K, Peng X, Xie S, Li X, Zhao S, Ma Y. Genome-Wide Patterns of Homozygosity and Relevant Characterizations on the Population Structure in Piétrain Pigs. Genes (Basel) 2020; 11:genes11050577. [PMID: 32455573 PMCID: PMC7291003 DOI: 10.3390/genes11050577] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/11/2020] [Accepted: 05/11/2020] [Indexed: 01/06/2023] Open
Abstract
Investigating the patterns of homozygosity, linkage disequilibrium, effective population size and inbreeding coefficients in livestock contributes to our understanding of the genetic diversity and evolutionary history. Here we used Illumina PorcineSNP50 Bead Chip to identify the runs of homozygosity (ROH) and estimate the linkage disequilibrium (LD) across the whole genome, and then predict the effective population size. In addition, we calculated the inbreeding coefficients based on ROH in 305 Piétrain pigs and compared its effect with the other two types of inbreeding coefficients obtained by different calculation methods. A total of 23,434 ROHs were detected, and the average length of ROH per individual was about 507.27 Mb. There was no regularity on how those runs of homozygosity distributed in genome. The comparisons of different categories suggested that the formation of long ROH was probably related with recent inbreeding events. Although the density of genes located in ROH core regions is lower than that in the other genomic regions, most of them are related with Piétrain commercial traits like meat qualities. Overall, the results provide insight into the way in which ROH is produced and the identified ROH core regions can be used to map the genes associated with commercial traits in domestic animals.
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Affiliation(s)
| | | | | | | | | | | | | | - Yunlong Ma
- Correspondence: ; Tel.: +86-027-87282091
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Torz LJ, Osborne-Lawrence S, Rodriguez J, He Z, Cornejo MP, Mustafá ER, Jin C, Petersen N, Hedegaard MA, Nybo M, Damonte VM, Metzger NP, Mani BK, Williams KW, Raingo J, Perello M, Holst B, Zigman JM. Metabolic insights from a GHSR-A203E mutant mouse model. Mol Metab 2020; 39:101004. [PMID: 32339772 PMCID: PMC7242877 DOI: 10.1016/j.molmet.2020.101004] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 04/13/2020] [Accepted: 04/16/2020] [Indexed: 02/02/2023] Open
Abstract
Objective Binding of ghrelin to its receptor, growth hormone secretagogue receptor (GHSR), stimulates GH release, induces eating, and increases blood glucose. These processes may also be influenced by constitutive (ghrelin-independent) GHSR activity, as suggested by findings in short people with naturally occurring GHSR-A204E mutations and reduced food intake and blood glucose in rodents administered GHSR inverse agonists, both of which impair constitutive GHSR activity. In this study, we aimed to more fully determine the physiologic relevance of constitutive GHSR activity. Methods We generated mice with a GHSR mutation that replaces alanine at position 203 with glutamate (GHSR-A203E), which corresponds to the previously described human GHSR-A204E mutation, and used them to conduct ex vivo neuronal electrophysiology and in vivo metabolic assessments. We also measured signaling within COS-7 and HEK293T cells transfected with wild-type GHSR (GHSR-WT) or GHSR-A203E constructs. Results In COS-7 cells, GHSR-A203E resulted in lower baseline IP3 accumulation than GHSR-WT; ghrelin-induced IP3 accumulation was observed in both constructs. In HEK293T cells co-transfected with voltage-gated CaV2.2 calcium channel complex, GHSR-A203E had no effect on basal CaV2.2 current density while GHSR-WT did; both GHSR-A203E and GHSR-WT inhibited CaV2.2 current in the presence of ghrelin. In cultured hypothalamic neurons from GHSR-A203E and GHSR-deficient mice, native calcium currents were greater than those in neurons from wild-type mice; ghrelin inhibited calcium currents in cultured hypothalamic neurons from both GHSR-A203E and wild-type mice. In brain slices, resting membrane potentials of arcuate NPY neurons from GHSR-A203E mice were hyperpolarized compared to those from wild-type mice; the same percentage of arcuate NPY neurons from GHSR-A203E and wild-type mice depolarized upon ghrelin exposure. The GHSR-A203E mutation did not significantly affect body weight, body length, or femur length in the first ∼6 months of life, yet these parameters were lower in GHSR-A203E mice after 1 year of age. During a 7-d 60% caloric restriction regimen, GHSR-A203E mice lacked the usual marked rise in plasma GH and demonstrated an exaggerated drop in blood glucose. Administered ghrelin also exhibited reduced orexigenic and GH secretagogue efficacies in GHSR-A203E mice. Conclusions Our data suggest that the A203E mutation ablates constitutive GHSR activity and that constitutive GHSR activity contributes to the native depolarizing conductance of GHSR-expressing arcuate NPY neurons. Although the A203E mutation does not block ghrelin-evoked signaling as assessed using in vitro and ex vivo models, GHSR-A203E mice lack the usual acute food intake response to administered ghrelin in vivo. The GHSR-A203E mutation also blunts GH release, and in aged mice leads to reduced body length and femur length, which are consistent with the short stature of human carriers of the GHSR-A204E mutation. We generated mice with a GHSR mutation replacing Ala at position 203 with Glu. The A203E mutation ablates constitutive GHSR activity & hyperpolarizes NPY neurons. GHSR-A203E mice lack the usual orexigenic response to administered ghrelin. The GHSR-A203E mutation blunts GH release and causes reduced body length. This finding is consistent with short stature in human carriers of the GHSR-A204E mutation.
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Affiliation(s)
- Lola J Torz
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Juan Rodriguez
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Zhenyan He
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | | | - Emilio Román Mustafá
- Laboratory of Electrophysiology of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA)], La Plata, Buenos Aires, Argentina
| | - Chunyu Jin
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Natalia Petersen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten A Hedegaard
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maja Nybo
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Valentina Martínez Damonte
- Laboratory of Electrophysiology of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA)], La Plata, Buenos Aires, Argentina
| | - Nathan P Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Bharath K Mani
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Kevin W Williams
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jesica Raingo
- Laboratory of Electrophysiology of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA)], La Plata, Buenos Aires, Argentina
| | - Mario Perello
- Laboratory of Neurophysiology, La Plata, Buenos Aires, Argentina
| | - Birgitte Holst
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark.
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA.
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Whipple AJ, Breton-Provencher V, Jacobs HN, Chitta UK, Sur M, Sharp PA. Imprinted Maternally Expressed microRNAs Antagonize Paternally Driven Gene Programs in Neurons. Mol Cell 2020; 78:85-95.e8. [PMID: 32032531 PMCID: PMC7176019 DOI: 10.1016/j.molcel.2020.01.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 12/03/2019] [Accepted: 01/15/2020] [Indexed: 12/24/2022]
Abstract
Imprinted genes with parental-biased allelic expression are frequently co-regulated and enriched in common biological pathways. Here, we functionally characterize a large cluster of microRNAs (miRNAs) expressed from the maternally inherited allele ("maternally expressed") to explore the molecular and cellular consequences of imprinted miRNA activity. Using an induced neuron (iN) culture system, we show that maternally expressed miRNAs from the miR-379/410 cluster direct the RNA-induced silencing complex (RISC) to transcriptional and developmental regulators, including paternally expressed transcripts like Plagl1. Maternal deletion of this imprinted miRNA cluster resulted in increased protein levels of several targets and upregulation of a broader transcriptional program regulating synaptic transmission and neuronal function. A subset of the transcriptional changes resulting from miR-379/410 deletion can be attributed to de-repression of Plagl1. These data suggest maternally expressed miRNAs antagonize paternally driven gene programs in neurons.
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Affiliation(s)
- Amanda J Whipple
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
| | - Vincent Breton-Provencher
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hannah N Jacobs
- Biological Sciences Department, Wellesley College, Wellesley, MA 02481, USA
| | - Udbhav K Chitta
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Mriganka Sur
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Phillip A Sharp
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Hedegaard MA, Holst B. The Complex Signaling Pathways of the Ghrelin Receptor. Endocrinology 2020; 161:5734640. [PMID: 32049280 DOI: 10.1210/endocr/bqaa020] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/10/2020] [Indexed: 12/13/2022]
Abstract
The ghrelin receptor (GhrR) is known for its strong orexigenic effects in pharmacological doses and has long been considered as a promising target for the treatment of obesity. Several antagonists have been developed to decrease the orexigenic signaling, but none of these have been approved for the treatment of obesity because of adverse effects and lack of efficacy. Heterodimerization and biased signaling are important concepts for G-protein coupled receptor (GPCR) signaling, and the influence of these aspects on the GhrR may be important for feeding behavior and obesity. GhrR has been described to heterodimerize with other GPCRs, such as the dopamine receptors 1 and 2, leading to a modulation of the signaling properties of both dimerization partners. Another complicating factor of GhrR-mediated signaling is its ability to activate several different signaling pathways on ligand stimulation. Importantly, some ligands have shown to be "biased" or "functionally selective," implying that the ligand favors a particular signaling pathway. These unique signaling properties could have a sizeable impact on the physiological functions of the GhrR system. Importantly, heterodimerization may explain why the GhrR is expressed in areas of the brain that are difficult for peptide ligands to access. One possibility is that the purpose of GhrR expression is to modulate the function of other receptors in addition to merely being independently activated. We suggest that a deeper understanding of the signaling properties of the GhrR will facilitate future drug discovery in the areas of obesity and weight management.
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Affiliation(s)
- Morten Adler Hedegaard
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Birgitte Holst
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
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Abizaid A, Hougland JL. Ghrelin Signaling: GOAT and GHS-R1a Take a LEAP in Complexity. Trends Endocrinol Metab 2020; 31:107-117. [PMID: 31636018 PMCID: PMC7299083 DOI: 10.1016/j.tem.2019.09.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/25/2019] [Accepted: 09/27/2019] [Indexed: 12/30/2022]
Abstract
Ghrelin and the growth hormone secretagogue receptor 1a (GHS-R1a) are important targets for disorders related to energy balance and metabolic regulation. Pharmacological control of ghrelin signaling is a promising avenue to address health issues involving appetite, weight gain, obesity, and related metabolic disorders, and may be an option for patients suffering from wasting conditions like cachexia. In this review, we summarize recent developments in the biochemistry of ghrelin and GHS-R1a signaling. These include unravelling the enzymatic transformations that generate active ghrelin and the discovery of multiple proteins that interact with ghrelin and GHS-R1a to regulate signaling. Furthermore, we propose that harnessing these processes will lead to highly selective treatments to address obesity, diabetes, and other metabolism-linked disorders.
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Affiliation(s)
- Alfonso Abizaid
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | - James L Hougland
- Department of Chemistry, Syracuse University, Syracuse, NY, USA.
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Rouault AAJ, Rosselli-Murai LK, Hernandez CC, Gimenez LE, Tall GG, Sebag JA. The GPCR accessory protein MRAP2 regulates both biased signaling and constitutive activity of the ghrelin receptor GHSR1a. Sci Signal 2020; 13:13/613/eaax4569. [PMID: 31911434 DOI: 10.1126/scisignal.aax4569] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ghrelin is a hormone secreted by the stomach during fasting periods and acts through its receptor, the growth hormone secretagogue 1a (GHSR1a), to promote food intake and prevent hypoglycemia. As such, GHSR1a is an important regulator of energy and glucose homeostasis and a target for the treatment of obesity. Here, we showed that the accessory protein MRAP2 altered GHSR1a signaling by inhibiting its constitutive activity, as well as by enhancing its G protein-dependent signaling and blocking the recruitment and signaling of β-arrestin in response to ghrelin. In addition, the effects of MRAP2 on the Gαq and β-arrestin pathways were independent and involved distinct regions of MRAP2. These findings may have implications for the regulation of ghrelin function in vivo and the role of MRAP2 in energy homeostasis. They also show that accessory proteins can bias signaling downstream of GPCRs in response to their endogenous agonist.
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Affiliation(s)
- Alix A J Rouault
- Department of Molecular Physiology and Biophysics, Fraternal Order of Eagles Diabetes Research Center, Iowa Neuroscience Institute, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA
| | | | - Ciria C Hernandez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Luis E Gimenez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gregory G Tall
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Julien A Sebag
- Department of Molecular Physiology and Biophysics, Fraternal Order of Eagles Diabetes Research Center, Iowa Neuroscience Institute, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA.
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Baron M, Maillet J, Huyvaert M, Dechaume A, Boutry R, Loiselle H, Durand E, Toussaint B, Vaillant E, Philippe J, Thomas J, Ghulam A, Franc S, Charpentier G, Borys JM, Lévy-Marchal C, Tauber M, Scharfmann R, Weill J, Aubert C, Kerr-Conte J, Pattou F, Roussel R, Balkau B, Marre M, Boissel M, Derhourhi M, Gaget S, Canouil M, Froguel P, Bonnefond A. Loss-of-function mutations in MRAP2 are pathogenic in hyperphagic obesity with hyperglycemia and hypertension. Nat Med 2019; 25:1733-1738. [PMID: 31700171 PMCID: PMC6858878 DOI: 10.1038/s41591-019-0622-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 09/25/2019] [Indexed: 12/31/2022]
Abstract
The G-protein-coupled receptor (GPCR) accessory protein MRAP2 is implicated in energy control in rodents, notably via melanocortin-4 receptor (MC4R)1. Although some MRAP2 mutations have been described in people with obesity1–3, their functional consequences on adiposity remain elusive. Using large-scale sequencing of MRAP2 in 9,418 people, we identified 23 rare heterozygous variants associated with increased obesity risk in both adults and children. Functional assessment of each variant shows that loss-of-function MRAP2 variants are pathogenic for monogenic hyperphagic obesity, with hyperglycemia and hypertension. This contrasts with other monogenic forms of obesity characterized by excessive hunger, including MC4R deficiency, that present with low blood pressure and normal glucose tolerance4. The pleiotropic metabolic effect of loss-of-function mutations in MRAP2 might be due to the failure of different MRAP2-regulated GPCRs in various tissues including pancreatic islets.
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Affiliation(s)
- Morgane Baron
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Julie Maillet
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Marlène Huyvaert
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Aurélie Dechaume
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Raphaël Boutry
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Hélène Loiselle
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Emmanuelle Durand
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Bénédicte Toussaint
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Emmanuel Vaillant
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Julien Philippe
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France.,Center for Human Disease Modeling, Duke University Medical Center, Durham, NC, USA
| | - Jérémy Thomas
- Laboratoire de Biochimie et Hormonologie, Centre de Biologie Pathologie, Centre Hospitalier Régional Universitaire, Lille, France
| | - Amjad Ghulam
- Laboratoire de Biochimie et Hormonologie, Centre de Biologie Pathologie, Centre Hospitalier Régional Universitaire, Lille, France
| | - Sylvia Franc
- CERITD (Centre d'Étude et de Recherche pour l'Intensification du Traitement du Diabète), Evry, France.,Department of Diabetes, Sud-Francilien Hospital, University Paris-Sud, Orsay, Corbeil-Essonnes, France
| | - Guillaume Charpentier
- CERITD (Centre d'Étude et de Recherche pour l'Intensification du Traitement du Diabète), Evry, France.,Department of Diabetes, Sud-Francilien Hospital, University Paris-Sud, Orsay, Corbeil-Essonnes, France
| | | | - Claire Lévy-Marchal
- Department of Clinical Epidemiology, Inserm CIE 05, Robert Debré Hospital, Paris, France
| | - Maïthé Tauber
- Endocrinology, Obesity, Bone Disease, Genetics and Medical Gynecology, Hôpital des Enfants, Inserm UMR 1043, Université Toulouse III-Paul Sabatier, Toulouse, France
| | - Raphaël Scharfmann
- Inserm U1016, Institut Cochin, Université Paris Descartes, Paris, France
| | - Jacques Weill
- Pediatric Endocrine Department, Lille Hospital, Lille, France
| | | | - Julie Kerr-Conte
- Inserm U1190, EGID, CHU Lille, University of Lille, Lille, France
| | - François Pattou
- Inserm U1190, EGID, CHU Lille, University of Lille, Lille, France
| | - Ronan Roussel
- Department of Diabetology, Endocrinology and Nutrition, Hôpital Bichat, DHU FIRE, Assistance Publique Hôpitaux de Paris, Paris, France.,Inserm U1138, Centre de Recherche des Cordeliers, Paris, France.,UFR de Médecine, University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Beverley Balkau
- Inserm U1018, Center for Research in Epidemiology and Population Health, Villejuif, France.,University Paris-Saclay, University Paris-Sud, Villejuif, France
| | - Michel Marre
- Inserm U1138, Centre de Recherche des Cordeliers, Paris, France.,CMC Ambroise Paré, Neuilly-sur-Seine, France
| | - Mathilde Boissel
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Mehdi Derhourhi
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Stefan Gaget
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Mickaël Canouil
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Philippe Froguel
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France. .,Department of Metabolism, Section of Genomics of Common Disease, Imperial College London, London, UK.
| | - Amélie Bonnefond
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France. .,Department of Metabolism, Section of Genomics of Common Disease, Imperial College London, London, UK.
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Yang LK, Zhang ZR, Wen HS, Tao YX. Characterization of channel catfish (Ictalurus punctatus) melanocortin-3 receptor reveals a potential network in regulation of energy homeostasis. Gen Comp Endocrinol 2019; 277:90-103. [PMID: 30905760 DOI: 10.1016/j.ygcen.2019.03.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 03/12/2019] [Accepted: 03/18/2019] [Indexed: 11/19/2022]
Abstract
The melanocortin-3 receptor (MC3R) is known to be involved in regulation of energy homeostasis, regulating feed efficiency and nutrient partitioning in mammals. Its physiological roles in non-mammalian vertebrates, especially economically important aquaculture species, are not well understood. Channel catfish (Ictalurus punctatus) is the main freshwater aquaculture species in North America. In this study, we characterized the channel catfish MC3R. The mc3r of channel catfish encoded a putative protein (ipMC3R) of 367 amino acids. We transfected HEK293T cells with ipMC3R plasmid for functional studies. Five agonists, including adrenocorticotropin, α-melanocyte stimulating hormone (α-MSH), β-MSH, [Nle4, D-Phe7]-α-MSH, and D-Trp8-γ-MSH, were used in the pharmacological studies. Our results showed that ipMC3R bound β-MSH with higher affinity and D-Trp8-γ-MSH with lower affinity compared with human MC3R. All agonists could stimulate ipMC3R and increase intracellular cAMP production with sub-nanomolar potencies. The extracellular signal-regulated kinases 1 and 2 (ERK1/2) activation could also be triggered by ipMC3R. The ipMC3R exhibited constitutive activities in both cAMP and ERK1/2 pathways, and Agouti-related protein served as an inverse agonist at ipMC3R, potently inhibiting the high basal cAMP level. Moreover, we showed that melanocortin receptor accessory protein 2 (MRAP2) preferentially modulated ipMC3R in cAMP production rather than ERK1/2 activation. Our study will assist further investigation of the physiological roles of the ipMC3R, especially in energy homeostasis, in channel catfish.
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Affiliation(s)
- Li-Kun Yang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Zheng-Rui Zhang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States; Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Hai-Shen Wen
- College of Fisheries, Ocean University of China, Qingdao, China
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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Maugham ML, Seim I, Thomas PB, Crisp GJ, Shah ET, Herington AC, Gregory LS, Nelson CC, Jeffery PL, Chopin LK. Limited short-term effects on human prostate cancer xenograft growth and epidermal growth factor receptor gene expression by the ghrelin receptor antagonist [D-Lys 3]-GHRP-6. Endocrine 2019; 64:393-405. [PMID: 30390209 DOI: 10.1007/s12020-018-1796-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 10/17/2018] [Indexed: 12/15/2022]
Abstract
PURPOSE The ghrelin axis regulates many physiological functions (including appetite, metabolism, and energy balance) and plays a role in disease processes. As ghrelin stimulates prostate cancer proliferation, the ghrelin receptor antagonist [D-Lys3]-GHRP-6 is a potential treatment for castrate-resistant prostate cancer and for preventing the metabolic consequences of androgen-targeted therapies. We therefore explored the effect of [D-Lys3]-GHRP-6 on PC3 prostate cancer xenograft growth. METHODS NOD/SCID mice with PC3 prostate cancer xenografts were administered 20 nmoles/mouse [D-Lys3]-GHRP-6 daily by intraperitoneal injection for 14 days and tumour volume and weight were measured. RNA sequencing of tumours was conducted to investigate expression changes following [D-Lys3]-GHRP-6 treatment. A second experiment, extending treatment time to 18 days and including a higher dose of [D-Lys3]-GHRP-6 (200 nmoles/mouse/day), was undertaken to ensure repeatability. RESULTS We demonstrate here that daily intraperitoneal injection of 20 nmoles/mouse [D-Lys3]-GHRP-6 reduces PC3 prostate cancer xenograft tumour volume and weight in NOD/SCID mice at two weeks post treatment initiation. RNA-sequencing revealed reduced expression of epidermal growth factor receptor (EGFR) in these tumours. Further experiments demonstrated that the effects of [D-Lys3]-GHRP-6 are transitory and lost after 18 days of treatment. CONCLUSIONS We show that [D-Lys3]-GHRP-6 has transitory effects on prostate xenograft tumours in mice, which rapidly develop an apparent resistance to the antagonist. Although further studies on [D-Lys3]-GHRP-6 are warranted, we suggest that daily treatment with the antagonist is not a suitable treatment for advanced prostate cancer.
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Affiliation(s)
- Michelle L Maugham
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Skeletal Biology and Forensic Anthropology Research Laboratory, Cancer Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Inge Seim
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, China
| | - Patrick B Thomas
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Gabrielle J Crisp
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Esha T Shah
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Adrian C Herington
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Laura S Gregory
- Skeletal Biology and Forensic Anthropology Research Laboratory, Cancer Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Colleen C Nelson
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Penny L Jeffery
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Lisa K Chopin
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia.
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia.
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia.
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Barney E, Dores MR, McAvoy D, Davis P, Racareanu RC, Iki A, Hyodo S, Dores RM. Elephant shark melanocortin receptors: Novel interactions with MRAP1 and implication for the HPI axis. Gen Comp Endocrinol 2019; 272:42-51. [PMID: 30468718 DOI: 10.1016/j.ygcen.2018.11.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 11/15/2018] [Accepted: 11/16/2018] [Indexed: 10/27/2022]
Abstract
The presence of Mrap1 and Mrap2 orthologs in the genome of the elephant shark (es), a cartilaginous fish, presented an opportunity to evaluate the potential interactions between these accessory proteins and melanocortin receptors of a cartilaginous fish. RT-PCR analysis indicated that Mrap1 mRNA was present in interrenal, brain, and pituitary tissue with mRNA for Mc2R, Mc3R, Mc4R, and Mc5r. Co-expression of esMrap1 cDNA with esMc2r cDNA or esMc5r cDNA in CHO cells increased sensitivity to stimulation with ACTH(1-24) 10 fold and 100 fold, respectfully, but had no effect on sensitivity to stimulation with DesAc-αMSH [i.e., ACTH(1-13)NH2] for either receptor, and had no effect on the ligand sensitivity of either esMc3r or esMc4r. Fluorescence image analysis indicated co-localization of esMrap1/esMc2r, and esMrap1/esMc5r on the plasma membrane; however, cell surface ELISA analysis indicated that co-expression with esMrap1 had no effect, positive or negative, on the trafficking of either esMc2r or esMc5r to the plasma membrane. RT-PCR analysis also indicated that Mrap2 mRNA, as well as, mRNAs for Mc2r, Mc3r, Mc4r, and Mc5r could be detected in brain tissue, however no Mrap2 mRNA was detected in interrenal tissue. Co-expression of esMrap2 in CHO cells with, respectively, esMc2r, esMc4r, or esMc5r had no effect on ligand sensitivity. However, co-expression of esMrap2 with esMc3r did lower sensitivity to stimulation by DesAc-αMSH 10 fold. These observations are discussed in the context of the parallel evolution of melanocortin receptors and their accessory proteins, and the hypothalamus/pituitary/adrenal axis and the hypothalamus/pituitary/interrenal axis in bony vertebrates and cartilaginous fishes.
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Affiliation(s)
- Emily Barney
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Michael R Dores
- Department of Biology, Hofstra University, Hampstead, NY, USA
| | - Danielle McAvoy
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Perry Davis
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | | | - Ayuko Iki
- Atmosphere and Ocean Research Institute, University of Tokyo, Chiba, Japan
| | - Susumu Hyodo
- Atmosphere and Ocean Research Institute, University of Tokyo, Chiba, Japan
| | - Robert M Dores
- Department of Biological Sciences, University of Denver, Denver, CO, USA.
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Soletto L, Hernández-Balfagó S, Rocha A, Scheerer P, Kleinau G, Cerdá-Reverter JM. Melanocortin Receptor Accessory Protein 2-Induced Adrenocorticotropic Hormone Response of Human Melanocortin 4 Receptor. J Endocr Soc 2019; 3:314-323. [PMID: 30652132 PMCID: PMC6330173 DOI: 10.1210/js.2018-00370] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 12/03/2018] [Indexed: 12/11/2022] Open
Abstract
Melanocortin 4 receptor (MC4R), a canonical melanocyte-stimulating hormone receptor, is the main responsible for monogenic obesity in humans. Previous studies in fish and avian species showed that MC4R becomes an ACTH receptor after interaction with the melanocortin receptor accessory protein 2 (MRAP2). We show that human MC4R behaves in a similar way through its interaction with MRAP2. This evolutionary conservation of MRAP2-induced ligand selectivity supports a physiological role for the interaction with MC4R. Both proteins are coexpressed in the same hypothalamic neurons, providing an anatomical substrate and molecular mechanism for the central therapeutic actions of ACTH in the treatment of infantile spasms. These neurons may link the effects of stress on the energy balance independently of glucocorticoid secretion. The complex MC4R-MRAP2 throws light on the action of ACTH and, by extension, on the relay of stress-related information to additional biological systems.
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Affiliation(s)
- Lucia Soletto
- Departamento de Fisiología de Peces y Biotecnología, Instituto de Acuicultura Torre de la Sal, Consejo Superior de Investigaciones Científicas, Castellón, Spain
| | - Sergio Hernández-Balfagó
- Departamento de Fisiología de Peces y Biotecnología, Instituto de Acuicultura Torre de la Sal, Consejo Superior de Investigaciones Científicas, Castellón, Spain
| | - Ana Rocha
- Departamento de Fisiología de Peces y Biotecnología, Instituto de Acuicultura Torre de la Sal, Consejo Superior de Investigaciones Científicas, Castellón, Spain
| | - Patrick Scheerer
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, D-10117 Berlin, Germany
| | - Gunnar Kleinau
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, D-10117 Berlin, Germany
| | - José Miguel Cerdá-Reverter
- Departamento de Fisiología de Peces y Biotecnología, Instituto de Acuicultura Torre de la Sal, Consejo Superior de Investigaciones Científicas, Castellón, Spain
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50
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Bruschetta G, Kim JD, Diano S, Chan LF. Overexpression of melanocortin 2 receptor accessory protein 2 (MRAP2) in adult paraventricular MC4R neurons regulates energy intake and expenditure. Mol Metab 2018; 18:79-87. [PMID: 30352741 PMCID: PMC6308034 DOI: 10.1016/j.molmet.2018.09.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 09/18/2018] [Accepted: 09/30/2018] [Indexed: 11/18/2022] Open
Abstract
Objective Melanocortin 2 receptor accessory protein 2 (MRAP2) has a critical role in energy homeostasis. Although MRAP2 has been shown to regulates a number of GPCRs involved in metabolism, the key neurons responsible for the phenotype of gross obesity in MRAP2 deficient animals are unclear. Furthermore, to date, all the murine MRAP2 models involve the prenatal deletion of MRAP2. Methods To target Melanocortin 4 receptor (MC4R)-expressing neurons in the hypothalamic paraventricular nucleus (PVN), we performed stereotaxic surgery using AAV to selectively overexpress MRAP2 postnatally in adult Mc4r-cre mice. We assessed energy homeostasis, glucose metabolism, core body temperature, and response to MC3R/MC4R agonist MTII. Results Mc4r-crePVN-MRAP2 female mice on a standard chow diet had less age-related weight gain and improved glucose/insulin profile compared to control Mc4r-crePVN-GFP mice. These changes were associated with a reduction in food intake and increased energy expenditure. In contrast, Mc4r-crePVN-MRAP2 male mice showed no improvement on a chow diet, but improvement of energy and glucose metabolism was observed following high fat diet (HFD) feeding. In addition, an increase in core body temperature was found in both females fed on standard chow diet and males fed on HFD. Mc4r-crePVN-MRAP2 female and male mice showed increased neuronal activation in the PVN compared to controls, with further increase in neuronal activation post MTII treatment in females. Conclusions Our data indicate a site-specific role for MRAP2 in PVN MC4R-expressing neurons in potentiating MC4R neuronal activation at baseline conditions in the regulation of food intake and energy expenditure. Postnatal overexpression of MRAP2 regulates energy balance, thermogenesis and glucose metabolism. Overexpression of MRAP2 in MC4R expressing neurons increases PVN neuronal activation. There is a sex difference in extent of metabolic protection, with a more marked lean phenotype in females.
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Affiliation(s)
- Giuseppe Bruschetta
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, CT, 06520, USA; Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Jung Dae Kim
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, CT, 06520, USA; Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Sabrina Diano
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, CT, 06520, USA; Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, CT, 06520, USA; Department of Neuroscience, Yale University School of Medicine, New Haven, CT, 06520, USA; Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, 06520, USA; Department of Clinical Medicine and Surgery, University of Naples "Federico II", Naples, Italy.
| | - Li F Chan
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK.
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