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Dai HC, Ji RL, Tao YX. SHU9119 and MBP10 are biased ligands at the human melanocortin-4 receptor. Biochem Pharmacol 2024:116325. [PMID: 38815629 DOI: 10.1016/j.bcp.2024.116325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 05/24/2024] [Accepted: 05/27/2024] [Indexed: 06/01/2024]
Abstract
The melanocortin-4 receptor (MC4R), a G protein-coupled receptor, is critically involved in regulating energy homeostasis as well as modulation of reproduction and sexual function. Two peptide antagonists (SHU9119 and MBP10) were derived from the endogenous agonist α-melanocyte stimulating hormone. But their pharmacology at human MC4R is not fully understood. Herein, we performed detailed pharmacological studies of SHU9119 and MBP10 on wild-type (WT) and six naturally occurring constitutively active MC4Rs. Both ligands had no or negligible agonist activity in Gαs-cAMP signaling on WT MC4R, but stimulated extracellular signal-regulated kinases 1 and 2 (ERK1/2) activation on WT and mutant MC4Rs. Mechanistic studies revealed that SHU9119 and MBP10 stimulated ERK1/2 signaling of MC4R by different mechanisms, with SHU9119-stimulated ERK1/2 signaling mediated by phosphatidylinositol 3-kinase (PI3K) and MBP10-initiated ERK1/2 activation through PI3K and β-arrestin. In summary, our studies demonstrated that SHU9119 and MBP10 were biased ligands for MC4R, preferentially activating ERK1/2 signaling through different mechanisms. SHU9119 acted as a biased ligand and MBP10 behaved as a biased allosteric modulator.
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Affiliation(s)
- Han-Chuan Dai
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States; College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
| | - Ren-Lei Ji
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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2
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Ji RL, Liu T, Hou ZS, Wen HS, Tao YX. Divergent Pharmacology and Biased Signaling of the Four Melanocortin-4 Receptor Isoforms in Rainbow Trout ( Oncorhynchus mykiss). Biomolecules 2023; 13:1248. [PMID: 37627313 PMCID: PMC10452266 DOI: 10.3390/biom13081248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/13/2023] [Accepted: 08/14/2023] [Indexed: 08/27/2023] Open
Abstract
The melanocortin-4 receptor (MC4R) is essential for the modulation of energy balance and reproduction in both fish and mammals. Rainbow trout (Oncorhynchus mykiss) has been extensively studied in various fields and provides a unique opportunity to investigate divergent physiological roles of paralogues. Herein we identified four trout mc4r (mc4ra1, mc4ra2, mc4rb1, and mc4rb2) genes. Four trout Mc4rs (omMc4rs) were homologous to those of teleost and mammalian MC4Rs. Multiple sequence alignments, a phylogenetic tree, chromosomal synteny analyses, and pharmacological studies showed that trout mc4r genes may have undergone different evolutionary processes. All four trout Mc4rs bound to two peptide agonists and elevated intracellular cAMP levels dose-dependently. High basal cAMP levels were observed at two omMc4rs, which were decreased by Agouti-related peptide. Only omMc4rb2 was constitutively active in the ERK1/2 signaling pathway. Ipsen 5i, ML00253764, and MCL0020 were biased allosteric modulators of omMc4rb1 with selective activation upon ERK1/2 signaling. ML00253764 behaved as an allosteric agonist in Gs-cAMP signaling of omMc4rb2. This study will lay the foundation for future physiological studies of various mc4r paralogs and reveal the evolution of MC4R in vertebrates.
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Affiliation(s)
- Ren-Lei Ji
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA; (R.-L.J.); (T.L.)
| | - Ting Liu
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA; (R.-L.J.); (T.L.)
| | - Zhi-Shuai Hou
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA; (R.-L.J.); (T.L.)
| | - Hai-Shen Wen
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266100, China;
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA; (R.-L.J.); (T.L.)
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3
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Seki S, Ohura K, Miyazaki T, Naser AA, Takabayashi S, Tsutsumi E, Tokumoto T. The Mc4r gene is responsible for the development of experimentally induced testicular teratomas. Sci Rep 2023; 13:6756. [PMID: 37127675 PMCID: PMC10151343 DOI: 10.1038/s41598-023-32784-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 04/02/2023] [Indexed: 05/03/2023] Open
Abstract
Teratomas in mice, composed of different tissue types, are derived from primordial germ cells in the fetal gonads. Previously, we identified a locus responsible for experimental testicular teratoma (ETT) formation on chromosome 18, referred to as ett1. The strongest candidate sequence in the ett1 locus was found to be a missense mutation in the melanocortin 4 receptor (Mc4r), Mc4rG25S. We established a strain with a point mutation in the Mc4r gene in the ETT-nonsusceptible LT strain, called LT- Mc4rG25S, by genome editing. Surprisingly, highly developed ovarian teratomas (OTs), rather than testicular teratomas, appeared in the LT-Mc4rG25S strain. The results demonstrated that Mc4r is also one of the genes responsible for OT formation and suggested that missense mutations in Mc4r promote teratoma formation in both sexes. In this study, we performed ETT experiments in different host-graft combinations of the LT-Mc4rG25S and LT strains. Furthermore, the expression of MC4R in germ cells in the testis was demonstrated. Expression of Mc4r in testis was also confirmed by RT-PCR. The results demonstrated that MC4R is expressed in germ cells in the testis and that a point mutation in the Mc4r gene is responsible for ETT formation.
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Affiliation(s)
- Syunsuke Seki
- Department of Bioscience, Faculty of Science, Shizuoka University, Shizuoka, 422, Japan
| | - Kaoru Ohura
- Department of Bioscience, Faculty of Science, Shizuoka University, Shizuoka, 422, Japan
| | - Takehiro Miyazaki
- Integrated Bioscience Section, Graduate School of Science and Technology, National University Corporation Shizuoka University, Ohya 836, Suruga-Ku, Shizuoka, 422-8529, Japan
- Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo, Kyoto, 606-8501, Japan
| | - Abdullah An Naser
- Department of Bioscience, Faculty of Science, Shizuoka University, Shizuoka, 422, Japan
| | - Shuji Takabayashi
- Laboratory Animal Facilities & Services, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-Ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Eisei Tsutsumi
- Biological Science Course, Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-Ku, Shizuoka, 422-8529, Japan
| | - Toshinobu Tokumoto
- Department of Bioscience, Faculty of Science, Shizuoka University, Shizuoka, 422, Japan.
- Integrated Bioscience Section, Graduate School of Science and Technology, National University Corporation Shizuoka University, Ohya 836, Suruga-Ku, Shizuoka, 422-8529, Japan.
- Biological Science Course, Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-Ku, Shizuoka, 422-8529, Japan.
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Neurotransmitters in Type 2 Diabetes and the Control of Systemic and Central Energy Balance. Metabolites 2023; 13:metabo13030384. [PMID: 36984824 PMCID: PMC10058084 DOI: 10.3390/metabo13030384] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 02/10/2023] [Accepted: 02/13/2023] [Indexed: 03/08/2023] Open
Abstract
Efficient signal transduction is important in maintaining the function of the nervous system across tissues. An intact neurotransmission process can regulate energy balance through proper communication between neurons and peripheral organs. This ensures that the right neural circuits are activated in the brain to modulate cellular energy homeostasis and systemic metabolic function. Alterations in neurotransmitters secretion can lead to imbalances in appetite, glucose metabolism, sleep, and thermogenesis. Dysregulation in dietary intake is also associated with disruption in neurotransmission and can trigger the onset of type 2 diabetes (T2D) and obesity. In this review, we highlight the various roles of neurotransmitters in regulating energy balance at the systemic level and in the central nervous system. We also address the link between neurotransmission imbalance and the development of T2D as well as perspectives across the fields of neuroscience and metabolism research.
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Yuan XC, Tao YX. Ligands for Melanocortin Receptors: Beyond Melanocyte-Stimulating Hormones and Adrenocorticotropin. Biomolecules 2022; 12:biom12101407. [PMID: 36291616 PMCID: PMC9599618 DOI: 10.3390/biom12101407] [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: 08/30/2022] [Revised: 09/25/2022] [Accepted: 09/28/2022] [Indexed: 11/16/2022] Open
Abstract
The discovery of melanocortins in 1916 has resulted in more than 100 years of research focused on these peptides. Extensive studies have elucidated well-established functions of melanocortins mediated by cell surface receptors, including MSHR (melanocyte-stimulating hormone receptor) and ACTHR (adrenocorticotropin receptor). Subsequently, three additional melanocortin receptors (MCRs) were identified. Among these five MCRs, MC3R and MC4R are expressed primarily in the central nervous system, and are therefore referred to as the neural MCRs. Since the central melanocortin system plays important roles in regulating energy homeostasis, targeting neural MCRs is emerging as a therapeutic approach for treating metabolic conditions such as obesity and cachexia. Early efforts modifying endogenous ligands resulted in the development of many potent and selective ligands. This review focuses on the ligands for neural MCRs, including classical ligands (MSH and agouti-related peptide), nonclassical ligands (lipocalin 2, β-defensin, small molecules, and pharmacoperones), and clinically approved ligands (ACTH, setmelanotide, bremelanotide, and several repurposed drugs).
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Affiliation(s)
- Xiao-Chen Yuan
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230061, China
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA
- Correspondence:
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Melanocortin-5 Receptor: Pharmacology and Its Regulation of Energy Metabolism. Int J Mol Sci 2022; 23:ijms23158727. [PMID: 35955857 PMCID: PMC9369360 DOI: 10.3390/ijms23158727] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 07/29/2022] [Accepted: 08/03/2022] [Indexed: 12/12/2022] Open
Abstract
As the most recent melanocortin receptor (MCR) identified, melanocortin-5 receptor (MC5R) has unique tissue expression patterns, pharmacological properties, and physiological functions. Different from the other four MCR subtypes, MC5R is widely distributed in both the central nervous system and peripheral tissues and is associated with multiple functions. MC5R in sebaceous and preputial glands regulates lipid production and sexual behavior, respectively. MC5R expressed in immune cells is involved in immunomodulation. Among the five MCRs, MC5R is the predominant subtype expressed in skeletal muscle and white adipose tissue, tissues critical for energy metabolism. Activated MC5R triggers lipid mobilization in adipocytes and glucose uptake in skeletal muscle. Therefore, MC5R is a potential target for treating patients with obesity and diabetes mellitus. Melanocortin-2 receptor accessory proteins can modulate the cell surface expression, dimerization, and pharmacology of MC5R. This minireview summarizes the molecular and pharmacological properties of MC5R and highlights the progress made on MC5R in energy metabolism. We poInt. out knowledge gaps that need to be explored in the future.
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Hammad MM, Mohammad A, Alam-Eldin N, Madhu D, Al-Mulla F, Abu-Farha M, Abubaker J. Structural analysis of setmelanotide binding to MC4R variants in comparison to wild-type receptor. Life Sci 2022; 307:120857. [PMID: 35931197 DOI: 10.1016/j.lfs.2022.120857] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 07/18/2022] [Accepted: 07/30/2022] [Indexed: 11/27/2022]
Abstract
AIMS Melanocortin 4 receptor (MC4R) has a well-established role in regulating appetite, food intake and energy homeostasis. Setmelanotide is an MC4R agonist currently approved for weight loss in obese adults and children with mutations in components of the leptin-melanocortin pathway. This study aims to compare structural and functional aspects of the physiological MC4R agonist α-melanocyte-stimulating hormone (α-MSH) with setmelanotide. We also aim to show the binding affinity of setmelanotide to known MC4R human missense mutations associated with obesity. MAIN METHODS AutoDock Vina was used in the structural analysis to calculate induced fit docking scores of ligand binding to MC4R wild type or the selected variants. HEK293-MC4R were utilized in the functional analysis of MC4R-actiavted pathways upon stimulating with α-MSH or setmelanotide. KEY FINDINGS Our data shows that setmelanotide has a higher potency for cAMP formation and a weaker effect on ERK1/2 phosphorylation when compared to α-MSH indicating functional selectivity otherwise known as biased agonism. We also present structural data showing that setmelanotide has a higher binding affinity to MC4R compared to α-MSH. Lastly, we show that two loss-of-function and two gain-of-function MC4R variants change the conformation not only of the ligand binding pocket of the receptor but also of the peptide when bound to the receptor because the interaction network and the residues involved in the binding are altered. SIGNIFICANCE Taken together, our study provides important insights into the diversity of MC4R signaling pathways which will facilitate the development of personalized anti-obesity drugs via refining MC4R agonists.
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Affiliation(s)
- Maha M Hammad
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Kuwait
| | - Anwar Mohammad
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Kuwait
| | - Nada Alam-Eldin
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Kuwait
| | - Dhanya Madhu
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Kuwait
| | - Fahd Al-Mulla
- Genetics and Bioinformatics Department, Dasman Diabetes Institute, Kuwait
| | - Mohamed Abu-Farha
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Kuwait.
| | - Jehad Abubaker
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Kuwait.
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Liu Z, Hruby VJ. MC4R biased signalling and the conformational basis of biological function selections. J Cell Mol Med 2022; 26:4125-4136. [PMID: 35818295 PMCID: PMC9344818 DOI: 10.1111/jcmm.17441] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 05/26/2022] [Accepted: 06/01/2022] [Indexed: 11/30/2022] Open
Abstract
The MC4R, a GPCR, has long been a major target for obesity treatment. As the most well‐studied melanocortin receptor subtype, the evolutionary knowledge pushes the drug development and structure–activity relationship (SAR) moving forward. The past decades have witnessed the evolution of scientists' view on GPCRs gradually from the control of a single canonical signalling pathway via a bilateral ‘active‐inactive’ model to a multi‐state alternative model where the ligands' binding affects the selection of the downstream signalling. This evolution brings the concept of biased signalling and the beginning of the next generation of peptide drug development, with the aim of turning from receptor subtype specificity to signalling pathway selectivity. The determination of the value structures of the MC4R revealed insights into the working mechanism of MC4R activation upon binding of agonists. However, new challenge has risen as we seek to unravel the mystery of MC4R signalling selection. Thus, more biased agonists and ligands with representative biological functions are needed to solve the rest of the puzzle.
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Affiliation(s)
- Zekun Liu
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, USA
| | - Victor J Hruby
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, USA
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Laiho L, Murray JF. The Multifaceted Melanocortin Receptors. Endocrinology 2022; 163:6608375. [PMID: 35700124 PMCID: PMC9214563 DOI: 10.1210/endocr/bqac083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Indexed: 12/05/2022]
Abstract
The 5 known melanocortin receptors (MCs) have established physiological roles. With the exception of MC2, these receptors can behave unpredictably, and since they are more widely expressed than their established roles would suggest, it is likely that they have other poorly characterized functions. The aim of this review is to discuss some of the less well-explored aspects of the 4 enigmatic members of this receptor family (MC1,3-5) and describe how these are multifaceted G protein-coupled receptors (GPCRs). These receptors appear to be promiscuous in that they bind several endogenous agonists (products of the proopiomelanocortin [POMC] gene) and antagonists but with inconsistent relative affinities and effects. We propose that this is a result of posttranslational modifications that determine receptor localization within nanodomains. Within each nanodomain there will be a variety of proteins, including ion channels, modifying proteins, and other GPCRs, that can interact with the MCs to alter the availability of receptor at the cell surface as well as the intracellular signaling resulting from receptor activation. Different combinations of interacting proteins and MCs may therefore give rise to the complex and inconsistent functional profiles reported for the MCs. For further progress in understanding this family, improved characterization of tissue-specific functions is required. Current evidence for interactions of these receptors with a range of partners, resulting in modulation of cell signaling, suggests that each should be studied within the full context of their interacting partners. The role of physiological status in determining this context also remains to be characterized.
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Affiliation(s)
- Linda Laiho
- Centre for Discovery Brain Sciences, School of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Joanne Fiona Murray
- Correspondence: J. F. Murray, PhD, Centre for Discovery Brain Sciences, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh EH8 9DX, UK.
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Jamieson BB, Piet R. Kisspeptin neuron electrophysiology: Intrinsic properties, hormonal modulation, and regulation of homeostatic circuits. Front Neuroendocrinol 2022; 66:101006. [PMID: 35640722 DOI: 10.1016/j.yfrne.2022.101006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 05/05/2022] [Accepted: 05/19/2022] [Indexed: 11/04/2022]
Abstract
The obligatory role of kisspeptin (KISS1) and its receptor (KISS1R) in regulating the hypothalamic-pituitary-gonadal axis, puberty and fertility was uncovered in 2003. In the few years that followed, an impressive body of work undertaken in many species established that neurons producing kisspeptin orchestrate gonadotropin-releasing hormone (GnRH) neuron activity and subsequent GnRH and gonadotropin hormone secretory patterns, through kisspeptin-KISS1R signaling, and mediate many aspects of gonadal steroid hormone feedback regulation of GnRH neurons. Here, we review knowledge accrued over the past decade, mainly in genetically modified mouse models, of the electrophysiological properties of kisspeptin neurons and their regulation by hormonal feedback. We also discuss recent progress in our understanding of the role of these cells within neuronal circuits that control GnRH neuron activity and GnRH secretion, energy balance and, potentially, other homeostatic and reproductive functions.
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Affiliation(s)
| | - Richard Piet
- Brain Health Research Institute and Department of Biological Sciences, Kent State University, Kent, OH, USA.
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Tao YX. Mutations in melanocortin-4 receptor: From fish to men. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 189:215-257. [PMID: 35595350 DOI: 10.1016/bs.pmbts.2022.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Melanocortin-4 receptor (MC4R), expressed abundantly in the hypothalamus, is a critical regulator of energy homeostasis, including both food intake and energy expenditure. Shortly after the publication in 1997 of the Mc4r knockout phenotypes in mice, including increased food intake and severe obesity, the first mutations in MC4R were reported in humans in 1998. Studies in the subsequent two decades have established MC4R mutation as the most common monogenic form of obesity, especially in early-onset severe obesity. Studies in animals, from fish to mammals, have established the conserved physiological roles of MC4R in all vertebrates in regulating energy balance. Drug targeting MC4R has been recently approved for treating morbid genetic obesity. How the MC4R can be exploited for animal production is highly worthy of active investigation.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, United States.
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Li Y, Wang X, Lu L, Wang M, Zhai Y, Tai X, Dilimulati D, Lei X, Xu J, Zhang C, Fu Y, Qu S, Li Q, Zhang C. Identification of novel GPCR partners of the central melanocortin signaling. Mol Metab 2021; 53:101317. [PMID: 34400348 PMCID: PMC8458986 DOI: 10.1016/j.molmet.2021.101317] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/03/2021] [Accepted: 08/10/2021] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE Homo- or heterodimerization of G protein-coupled receptors (GPCRs) generally affects the normal functioning of these receptors and mediates the responses to a variety of physiological stimuli in vivo. It is well known that melanocortin-3 receptor (MC3R) and melanocortin-4 receptor (MC4R) are key regulators of appetite and energy homeostasis in the central nervous system. However, the GPCR partners of MC3R and MC4R are not well understood. Our objective is to analyze single cell RNA-seq datasets of the hypothalamus to explore and identify novel GPCR partners of MC3R and MC4R and examine the pharmacological effect on the downstream signal transduction and membrane translocation of melanocortin receptors. METHODS We conducted an integrative analysis of multiple single cell RNA-seq datasets to reveal the expression pattern and correlation of GPCR families in the mouse hypothalamus. The emerging GPCRs with important metabolic functions were selected for cloning and co-immunoprecipitation validation. The positive GPCR partners were then tested for the pharmacological activation, competitive binding assay and surface translocation ELISA experiments. RESULTS Based on the expression pattern of GPCRs and their function enrichment results, we narrowed down the range of potential GPCR interaction with MC3R and MC4R for further confirmation. Co-immunoprecipitation assay verified 23 and 32 novel GPCR partners that interacted with MC3R and MC4R in vitro. The presence of these GPCR partners exhibited different effects in the physiological regulation and signal transduction of MC3R and MC4R. CONCLUSIONS This work represented the first large-scale screen for the functional GPCR complex of central melanocortin receptors and defined a composite metabolic regulatory GPCR network of the hypothalamic nucleuses.
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Affiliation(s)
- Yunpeng Li
- Department of Endocrinology and Metabolism, National Metabolic Management Center, Shanghai Tenth People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xiaozhu Wang
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Shanghai East Hospital, Tongji University, Shanghai, China.
| | - Liumei Lu
- Department of Endocrinology and Metabolism, National Metabolic Management Center, Shanghai Tenth People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - 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
- Department of Endocrinology and Metabolism, National Metabolic Management Center, Shanghai Tenth People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xiaolu Tai
- Department of Endocrinology and Metabolism, National Metabolic Management Center, Shanghai Tenth People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Diliqingna Dilimulati
- Department of Endocrinology and Metabolism, National Metabolic Management Center, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Xiaowei Lei
- Department of Endocrinology and Metabolism, National Metabolic Management Center, Shanghai Tenth People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jing Xu
- Department of Endocrinology and Metabolism, National Metabolic Management Center, Shanghai Tenth People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, 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
| | - Yanbin Fu
- 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
| | - Shen Qu
- Department of Endocrinology and Metabolism, National Metabolic Management Center, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China.
| | - 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.
| | - 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.
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Merkley CM, Shuping SL, Sommer JR, Nestor CC. Evidence That Agouti-Related Peptide May Directly Regulate Kisspeptin Neurons in Male Sheep. Metabolites 2021; 11:138. [PMID: 33652696 PMCID: PMC7996775 DOI: 10.3390/metabo11030138] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/19/2021] [Accepted: 02/23/2021] [Indexed: 12/21/2022] Open
Abstract
Agouti-related peptide (AgRP) neurons, which relay information from peripheral metabolic signals, may constitute a key central regulator of reproduction. Given that AgRP inhibits luteinizing hormone (LH) secretion and that nutritional suppression of LH elicits an increase in AgRP while suppressing kisspeptin expression in the arcuate nucleus (ARC) of the hypothalamus, we sought to examine the degree to which AgRP could directly regulate ARC kisspeptin neurons. Hypothalamic tissue was collected from four castrated male sheep (10 months of age) and processed for the detection of protein (AgRP input to kisspeptin neurons) using immunohistochemistry and mRNA for melanocortin 3 and 4 receptors (MC3R; MC4R) in kisspeptin neurons using RNAscope. Immunohistochemical analysis revealed that the majority of ARC kisspeptin neurons are contacted by presumptive AgRP terminals. RNAscope analysis revealed that nearly two thirds of the ARC kisspeptin neurons express mRNA for MC3R, while a small percentage (<10%) colocalize MC4R. Taken together, this data provides neuroanatomical evidence for a direct link between orexigenic AgRP neurons and reproductively critical kisspeptin neurons in the sheep, and builds upon our current understanding of the central link between energy balance and reproduction.
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Affiliation(s)
| | | | | | - Casey C Nestor
- Department of Animal Science, North Carolina State University, Raleigh, NC 27695, USA; (C.M.M.); (S.L.S.); (J.R.S.)
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14
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Aslanoglou D, Bertera S, Sánchez-Soto M, Benjamin Free R, Lee J, Zong W, Xue X, Shrestha S, Brissova M, Logan RW, Wollheim CB, Trucco M, Yechoor VK, Sibley DR, Bottino R, Freyberg Z. Dopamine regulates pancreatic glucagon and insulin secretion via adrenergic and dopaminergic receptors. Transl Psychiatry 2021; 11:59. [PMID: 33589583 PMCID: PMC7884786 DOI: 10.1038/s41398-020-01171-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/13/2020] [Accepted: 10/26/2020] [Indexed: 01/14/2023] Open
Abstract
Dopamine (DA) and norepinephrine (NE) are catecholamines primarily studied in the central nervous system that also act in the pancreas as peripheral regulators of metabolism. Pancreatic catecholamine signaling has also been increasingly implicated as a mechanism responsible for the metabolic disturbances produced by antipsychotic drugs (APDs). Critically, however, the mechanisms by which catecholamines modulate pancreatic hormone release are not completely understood. We show that human and mouse pancreatic α- and β-cells express the catecholamine biosynthetic and signaling machinery, and that α-cells synthesize DA de novo. This locally-produced pancreatic DA signals via both α- and β-cell adrenergic and dopaminergic receptors with different affinities to regulate glucagon and insulin release. Significantly, we show DA functions as a biased agonist at α2A-adrenergic receptors, preferentially signaling via the canonical G protein-mediated pathway. Our findings highlight the interplay between DA and NE signaling as a novel form of regulation to modulate pancreatic hormone release. Lastly, pharmacological blockade of DA D2-like receptors in human islets with APDs significantly raises insulin and glucagon release. This offers a new mechanism where APDs act directly on islet α- and β-cell targets to produce metabolic disturbances.
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Affiliation(s)
- Despoina Aslanoglou
- grid.21925.3d0000 0004 1936 9000Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA USA
| | - Suzanne Bertera
- grid.417046.00000 0004 0454 5075Institute of Cellular Therapeutics, Allegheny Health Network Research Institute, Allegheny Health Network, Pittsburgh, PA USA
| | - Marta Sánchez-Soto
- grid.94365.3d0000 0001 2297 5165Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD USA
| | - R. Benjamin Free
- grid.94365.3d0000 0001 2297 5165Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD USA
| | - Jeongkyung Lee
- grid.21925.3d0000 0004 1936 9000Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Diabetes and Beta Cell Biology Center, University of Pittsburgh, Pittsburgh, PA USA
| | - Wei Zong
- grid.21925.3d0000 0004 1936 9000Department of Biostatistics, University of Pittsburgh, Pittsburgh, PA USA
| | - Xiangning Xue
- grid.21925.3d0000 0004 1936 9000Department of Biostatistics, University of Pittsburgh, Pittsburgh, PA USA
| | - Shristi Shrestha
- grid.412807.80000 0004 1936 9916Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN USA
| | - Marcela Brissova
- grid.412807.80000 0004 1936 9916Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN USA
| | - Ryan W. Logan
- grid.21925.3d0000 0004 1936 9000Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA USA ,grid.249880.f0000 0004 0374 0039Center for Systems Neurogenetics of Addiction, The Jackson Laboratory, Bar Harbor, ME USA
| | - Claes B. Wollheim
- grid.8591.50000 0001 2322 4988Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Massimo Trucco
- grid.417046.00000 0004 0454 5075Institute of Cellular Therapeutics, Allegheny Health Network Research Institute, Allegheny Health Network, Pittsburgh, PA USA ,grid.147455.60000 0001 2097 0344Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA USA ,grid.166341.70000 0001 2181 3113College of Medicine, Drexel University, Philadelphia, PA USA
| | - Vijay K. Yechoor
- grid.21925.3d0000 0004 1936 9000Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Diabetes and Beta Cell Biology Center, University of Pittsburgh, Pittsburgh, PA USA
| | - David R. Sibley
- grid.94365.3d0000 0001 2297 5165Molecular Neuropharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD USA
| | - Rita Bottino
- grid.417046.00000 0004 0454 5075Institute of Cellular Therapeutics, Allegheny Health Network Research Institute, Allegheny Health Network, Pittsburgh, PA USA ,grid.147455.60000 0001 2097 0344Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA USA ,grid.166341.70000 0001 2181 3113College of Medicine, Drexel University, Philadelphia, PA USA
| | - Zachary Freyberg
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA. .,Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA.
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15
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Naser AA, Miyazaki T, Wang J, Takabayashi S, Pachoensuk T, Tokumoto T. MC4R mutant mice develop ovarian teratomas. Sci Rep 2021; 11:3483. [PMID: 33568756 PMCID: PMC7876032 DOI: 10.1038/s41598-021-83001-w] [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] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 01/19/2021] [Indexed: 01/05/2023] Open
Abstract
Teratomas in mice, composed of different tissue types, are derived from primordial germ cells (PGCs) in the foetal gonads. The strongest candidate gene in the testicular teratoma locus (Ter) responsible for testicular teratoma formation was identified as mutation in Dnd1, Dnd1R178*. However, the phenotype of mice with a mutated Dnd1 gene was germ cell loss. This suggests that other genes are involved in teratoma formation. Testicular teratomas can also be induced experimentally (experimentally testicular teratomas: ETTs) in 129/Sv mice by transplanting E12.5 foetal testes into adult testes. Previously, we mapped the ett1 locus, which is the locus responsible for ETT formation on chromosome 18. By exome sequence analysis of the 129 and LTXBJ (LT) strains, we identified a missense mutation in the melanocortin 4 receptor (MC4R) gene among 8 genes in the ett1 region. The missense mutation causes a substitution of glycine 25 by serine. Thus, this gene is a candidate for ETT formation. We established the LT-ett1 congenic strain, which introduced the locus responsible for ETT formation genetically into the genomes of a testicular teratoma non-susceptible strain. In this study, we crossed LT-ett1 and a previously established LT-Ter strain to establish the double congenic strain LT-Ter-ett1. Also, we established a strain with a point mutation in the MC4R gene of the LT strain by genome editing, LT-MC4RG25S. Furthermore, double genetically modified strain LT-Ter-MC4RG25S was established to address the relation between Ter and MC4R. Surprisingly, highly developed ovarian teratomas (OTs), instead of testicular teratomas, appeared not only in the LT-Ter-MC4RG25S and LT-MC4RG25S strains but also in the LT-ett1 and LT-Ter-ett1 strains. The incidence of OT formation was high in double genetically modified strains. The results demonstrated that MC4R is one of the genes responsible for OT formation. It was suggested that the effect of the missense mutation in MC4R on teratoma formation was promoted by abnormal germ cell formation by the mutation in DND1.
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Affiliation(s)
- Abdullah An Naser
- Integrated Bioscience Section, Graduate School of Science and Technology, National University Corporation Shizuoka University, Ohya 836, Suruga-ku, Shizuoka, 422-8529, Japan
| | - Takehiro Miyazaki
- Integrated Bioscience Section, Graduate School of Science and Technology, National University Corporation Shizuoka University, Ohya 836, Suruga-ku, Shizuoka, 422-8529, Japan
- Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo, Kyoto, 606-8501, Japan
| | - Jun Wang
- Department of Bioscience, Faculty of Science, Shizuoka University, Shizuoka, 422, Japan
| | - Shuji Takabayashi
- Laboratory Animal Facilities & Services, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Theeranukul Pachoensuk
- Integrated Bioscience Section, Graduate School of Science and Technology, National University Corporation Shizuoka University, Ohya 836, Suruga-ku, Shizuoka, 422-8529, Japan
| | - Toshinobu Tokumoto
- Integrated Bioscience Section, Graduate School of Science and Technology, National University Corporation Shizuoka University, Ohya 836, Suruga-ku, Shizuoka, 422-8529, Japan.
- Department of Bioscience, Faculty of Science, Shizuoka University, Shizuoka, 422, Japan.
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16
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Zhang HJ, Cui ZH, Liu M, Min TQ, Xiao X, Wang ZQ, Tao YX. Pharmacological characterization of three chicken melanocortin-3 receptor mutants. Domest Anim Endocrinol 2021; 74:106507. [PMID: 32841887 DOI: 10.1016/j.domaniend.2020.106507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 06/01/2020] [Accepted: 06/01/2020] [Indexed: 10/24/2022]
Abstract
The melanocortin-3 receptor (MC3R) is a G protein-coupled receptor and potentially important in production traits. Three naturally occurring mutations (M54L, G104S, and L151R) in chicken MC3R (cMC3R) were reported previously to be associated with production traits. Here, we inserted the full-length cMC3R coding sequence into pcDNA3.1(+) and generated the 3 mutations by site-directed mutagenesis. The total and cell surface expression of the receptors was measured by flow cytometry. We analyzed the pharmacological characteristics, including binding and cyclic adenosine monophosphate (cAMP) and mitogen-activated protein kinase (MAPK) signaling, using 6 ligands ([Nle4, D-Phe7]-α-melanocyte stimulating hormone (MSH), α-, β-, γ-, and D-Trp8-γ-MSHs, and agouti-related peptide). All mutants had similar total and cell surface expression as the wild-type (WT) cMC3R. M54L had similar pharmacological properties as the WT cMC3R. G104S did not exhibit any specific binding but had minimal response to α-, β-, γ-, and D-Trp8-γ-MSH, although it generated 24% WT response when stimulated by NDP-MSH. Although L151R had normal binding, the responses to agonists were reduced to approximately 25% of that of the WT. In MAPK signaling, all 3 mutants showed significantly increased agonist-stimulated phosphorylation of extracellular signal-regulated protein kinases 1/2, indicating the existence of biased signaling at G104S and L151R. In summary, our studies demonstrated that although all 3 mutations are significantly associated with production traits, only G104S and L151R had severe defects in receptor pharmacology. How M54L might cause production trait differences remains to be investigated.
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Affiliation(s)
- H-J Zhang
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, People's Republic of China; Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA
| | - Z-H Cui
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, People's Republic of China
| | - M Liu
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, People's Republic of China
| | - T-Q Min
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, People's Republic of China
| | - X Xiao
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, People's Republic of China
| | - Z-Q Wang
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, People's Republic of China.
| | - Y-X Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA.
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17
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Yang LK, Hou ZS, Tao YX. Biased signaling in naturally occurring mutations of G protein-coupled receptors associated with diverse human diseases. Biochim Biophys Acta Mol Basis Dis 2021; 1867:165973. [PMID: 32949766 PMCID: PMC7722056 DOI: 10.1016/j.bbadis.2020.165973] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/07/2020] [Accepted: 09/14/2020] [Indexed: 12/15/2022]
Abstract
G protein-coupled receptors (GPCRs) play critical roles in transmitting a variety of extracellular signals into the cells and regulate diverse physiological functions. Naturally occurring mutations that result in dysfunctions of GPCRs have been known as the causes of numerous diseases. Significant progresses have been made in elucidating the pathophysiology of diseases caused by mutations. The multiple intracellular signaling pathways, such as G protein-dependent and β-arrestin-dependent signaling, in conjunction with recent advances on biased agonism, have broadened the view on the molecular mechanism of disease pathogenesis. This review aims to briefly discuss biased agonism of GPCRs (biased ligands and biased receptors), summarize the naturally occurring GPCR mutations that cause biased signaling, and propose the potential pathophysiological relevance of biased mutant GPCRs associated with various endocrine diseases.
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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
| | - Zhi-Shuai Hou
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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18
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Sharfman N, Gilpin NW. The Role of Melanocortin Plasticity in Pain-Related Outcomes After Alcohol Exposure. Front Psychiatry 2021; 12:764720. [PMID: 34803772 PMCID: PMC8599269 DOI: 10.3389/fpsyt.2021.764720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/05/2021] [Indexed: 11/13/2022] Open
Abstract
The global COVID-19 pandemic has shone a light on the rates and dangers of alcohol misuse in adults and adolescents in the US and globally. Alcohol exposure during adolescence causes persistent molecular, cellular, and behavioral changes that increase the risk of alcohol use disorder (AUD) into adulthood. It is established that alcohol abuse in adulthood increases the likelihood of pain hypersensitivity and the genesis of chronic pain, and humans report drinking alcohol to relieve pain symptoms. However, the longitudinal effects of alcohol exposure on pain and the underlying CNS signaling that mediates it are understudied. Specific brain regions mediate pain effects, alcohol effects, and pain-alcohol interactions, and neural signaling in those brain regions is modulated by neuropeptides. The CNS melanocortin system is sensitive to alcohol and modulates pain sensitivity, but this system is understudied in the context of pain-alcohol interactions. In this review, we focus on the role of melanocortin signaling in brain regions sensitive to alcohol and pain, in particular the amygdala. We also discuss interactions of melanocortins with other peptide systems, including the opioid system, as potential mediators of pain-alcohol interactions. Therapeutic strategies that target the melanocortin system may mitigate the negative consequences of alcohol misuse during adolescence and/or adulthood, including effects on pain-related outcomes.
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Affiliation(s)
- Nathan Sharfman
- Department of Physiology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Nicholas W Gilpin
- Department of Physiology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA, United States.,Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, United States.,Alcohol and Drug Abuse Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA, United States.,Southeast Louisiana VA Healthcare System (SLVHCS), New Orleans, LA, United States
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19
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Yang LK, Tao YX. Alanine Scanning Mutagenesis of the DRYxxI Motif and Intracellular Loop 2 of Human Melanocortin-4 Receptor. Int J Mol Sci 2020; 21:ijms21207611. [PMID: 33076233 PMCID: PMC7589821 DOI: 10.3390/ijms21207611] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/10/2020] [Accepted: 10/11/2020] [Indexed: 12/15/2022] Open
Abstract
The melanocortin-4 receptor (MC4R) is a member of the G-protein-coupled receptor (GPCR) superfamily, which has been extensively studied in obesity pathogenesis due to its critical role in regulating energy homeostasis. Both the Gs-cAMP and ERK1/2 cascades are known as important intracellular signaling pathways initiated by the MC4R. The DRYxxI motif at the end of transmembrane domain 3 and the intracellular loop 2 (ICL2) are thought to be crucial for receptor function in several GPCRs. To study the functions of this domain in MC4R, we performed alanine-scanning mutagenesis on seventeen residues. We showed that one residue was critical for receptor cell surface expression. Eight residues were important for ligand binding. Mutations of three residues impaired Gs-cAMP signaling without changing the binding properties. Investigation on constitutive activities of all the mutants in the cAMP pathway revealed that six residues were involved in constraining the receptor in inactive states and five residues were important for receptor activation in the absence of an agonist. In addition, mutations of four residues impaired the ligand-stimulated ERK1/2 signaling pathway without affecting the binding properties. We also showed that some mutants were biased to the Gs-cAMP or ERK1/2 signaling pathway. In summary, we demonstrated that the DRYxxI motif and ICL2 were important for MC4R function.
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20
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Yang Z, Liang XF, Li GL, Tao YX. Biased signaling in fish melanocortin-4 receptors (MC4Rs): Divergent pharmacology of four ligands on spotted scat (Scatophagus argus) and grass carp (Ctenopharyngodon idella) MC4Rs. Mol Cell Endocrinol 2020; 515:110929. [PMID: 32615281 DOI: 10.1016/j.mce.2020.110929] [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: 05/15/2020] [Revised: 06/19/2020] [Accepted: 06/24/2020] [Indexed: 12/24/2022]
Abstract
The melanocortin-4 receptor (MC4R) plays a critical role in the regulation of energy homeostasis in both mammals and fish. Several fish MC4Rs recently characterized have high constitutive activities, potentially associated with food intake and growth rate. In the present study, we systematically investigated the effects of four human MC4R (hMC4R) antagonists, including agouti-related peptide (AgRP), Ipsen 5i, ML00253764, and MCL0020, on the cAMP and ERK1/2 signaling of two fish MC4Rs: spotted scat (Scatophagus argus) MC4R (saMC4R) and grass carp (Ctenopharyngodon idella) MC4R (ciMC4R), with hMC4R as a control. We showed that both saMC4R and ciMC4R were constitutively active with significantly increased basal cAMP levels. AgRP acted as an inverse agonist in cAMP signaling pathway in both fish MC4Rs whereas MCL0020 functioned as an inverse agonist for ciMC4R but a weak neutral antagonist for saMC4R. Ipsen 5i and MCL0020 behaved as neutral allosteric modulators in the cAMP signaling of fish MC4Rs. The saMC4R and ciMC4R had similar basal pERK1/2 levels as hMC4R and the pERK1/2 levels of the two fish MC4Rs were significantly increased upon stimulation with all four ligands. In summary, our studies demonstrated the existence of biased signaling in fish MC4R. We also showed dramatic pharmacological differences of human and fish MC4Rs with synthetic ligands. Our data provided novel insights and led to a better understanding of fish MC4R pharmacology.
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Affiliation(s)
- Zhao Yang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, 36849, United States
| | - Xu-Fang Liang
- College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Hubei Collaborative Innovation Center for Freshwater Aquaculture, Wuhan, Hubei, 430070, China
| | - Guang-Li Li
- Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, 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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21
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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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22
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Hammad MM, Abu-Farha M, Hebbar P, Cherian P, Al Khairi I, Melhem M, Alkayal F, Alsmadi O, Thanaraj TA, Al-Mulla F, Abubaker J. MC4R Variant rs17782313 Associates With Increased Levels of DNAJC27, Ghrelin, and Visfatin and Correlates With Obesity and Hypertension in a Kuwaiti Cohort. Front Endocrinol (Lausanne) 2020; 11:437. [PMID: 32733386 PMCID: PMC7358550 DOI: 10.3389/fendo.2020.00437] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 06/03/2020] [Indexed: 12/26/2022] Open
Abstract
Melanocortin 4 receptor (MC4R), a notable component of the melanocortin system, regulates appetite, body weight, and energy homeostasis. Genome-wide association studies have identified several MC4R variants associated with adiposity; of these, rs17782313, which is associated with increased body mass index (BMI) and overeating behavior, is of particular interest. Another gene associated with increased adiposity in global genome-wide association studies is DNAJC27, a heat shock protein known to be elevated in obesity. The detailed mechanisms underlying the role of MC4R variants in the biological pathways underlying metabolic disorders are not well-understood. To address this, we assessed variations of rs17782313 in a cohort of 282 Arab individuals from Kuwait, who are deeply phenotyped for anthropometric and metabolic traits and various biomarkers, including DNAJC27. Association tests showed that the rs17782313_C allele was associated with BMI and DNAJC27 levels. Increased levels of DNAJC27 reduced the MC4R-mediated formation of cAMP in MC4R ACTOne stable cells. In conclusion, this study demonstrated an association between the rs17782313 variant near MC4R and increased BMI and DNAJC27 levels and established a link between increased DNAJC27 levels and lower cAMP levels. We propose that regulation of MC4R activity by DNAJC27 enhances appetite through its effect on cAMP, thereby regulating obesity.
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Affiliation(s)
- Maha M. Hammad
- Research Division, Department of Biochemistry and Molecular Biology, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Mohamed Abu-Farha
- Research Division, Department of Biochemistry and Molecular Biology, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Prashantha Hebbar
- Research Division, Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Preethi Cherian
- Research Division, Department of Biochemistry and Molecular Biology, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Irina Al Khairi
- Research Division, Department of Biochemistry and Molecular Biology, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Motasem Melhem
- Research Division, Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Fadi Alkayal
- Research Division, Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Kuwait City, Kuwait
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | | | - Thangavel Alphonse Thanaraj
- Research Division, Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Kuwait City, Kuwait
- *Correspondence: Thangavel Alphonse Thanaraj
| | - Fahd Al-Mulla
- Research Division, Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Kuwait City, Kuwait
- Fahd Al-Mulla
| | - Jehad Abubaker
- Research Division, Department of Biochemistry and Molecular Biology, Dasman Diabetes Institute, Kuwait City, Kuwait
- Jehad Abubaker
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Min T, Liu M, Zhang H, Liu Y, Wang Z. Molecular and pharmacological characterization of poultry (Gallus gallus, Anas platyrhynchos, Anser cygnoides domesticus) and pig (Sus scrofa domestica) melanocortin-5 receptors and their mutants. Gen Comp Endocrinol 2019; 283:113233. [PMID: 31356812 DOI: 10.1016/j.ygcen.2019.113233] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 07/08/2019] [Accepted: 07/25/2019] [Indexed: 12/25/2022]
Abstract
The melanocortin-5 receptor (MC5R) is a member of the G protein-coupled receptor superfamily that plays a critical role in lipid production, skeletal muscle fatty acid oxidation, and adipocyte lipolysis. Although multiple functions and important value of MC5R in human beings have been fully demonstrated, however, the potential molecular cloning, pharmacological characteristics and key amino acids in poultry and pig were still not fully understood. Herein, we successfully cloned MC5R genes from chicken (Gallus gallus, cMC5R), duck (Anas platyrhynchos, dMC5R), goose (Anser cygnoides domesticus, gMC5R) and pig (Sus scrofa domestica, pMC5R), and compared their genetic and protein difference with hMC5R through phylogenetic analysis and homology models. Besides, we constructed three alanine-substitution mutants for each of MC5Rs through homologous reorganization, including c/d/gMC5R-D119A/F254A/H257A and pMC5R-D204A/F339A/H342A. Subsequently, we focused our investigation on the pharmacological characterization of four wide-type MC5Rs and their mutants in HEK293T cells, including the intracellular cAMP generation and phosphorylation level of ERK1/2. The results showed that these mutants had decreased cAMP levels under the stimulation of ligands, in spite of enhanced basal activity for c/d/gF254A and pH342A, indicating their important roles in the location and activation of receptors. Notably, these MC5Rs and mutants displayed significant species-specific phenotypes in the activation of pERK1/2 with ligands, which was not completely consistent with hMC5R. These findings demonstrated that presence of interspecies differences for MC5Rs, particularly for the pERK1/2 pathway. Taken together, our study expands current knowledge about the molecular and pharmacological characterization of c/d/g/pMC5Rs, providing preliminary data for MC5R-targeted drug screening or genetic breeding of economic animals in the future.
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Affiliation(s)
- Tianqi Min
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Min Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Haijie Zhang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Yuan Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, China; Institute of Comparative Medicine, Yangzhou University, Yangzhou, Jiangsu, China.
| | - Zhiqiang Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, China.
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Gillyard T, Fowler K, Williams SY, Cone RD. Obesity-associated mutant melanocortin-4 receptors with normal Gα s coupling frequently exhibit other discoverable pharmacological and biochemical defects. J Neuroendocrinol 2019; 31:e12795. [PMID: 31529534 DOI: 10.1111/jne.12795] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 08/11/2019] [Accepted: 09/10/2019] [Indexed: 01/04/2023]
Abstract
Mutations in the melanocortin-4 receptor (MC4R) are the most common cause of early syndromic obesity known. Most of these mutations result in a loss of protein expression, α-melanocyte-stimulating hormone binding, receptor trafficking or coupling to the stimulatory G-protein, Gαs . However, approximately 26% of the obesity-associated mutations characterised to date exhibit none of these pharmacological defects. In the present study, we investigated seven of these apparently normal mutant MC4R in more detail and found that the majority (five of the seven) exhibit marked defects including defective binding of another endogenous melanocortin ligand, defective glycosylation, and defective recruitment of β-arrestin. These data provide support for two hypotheses: (i) that the majority of these rare, obesity-associated mutations are likely defective and causative of obesity and (ii) that β-arrestin recruitment is a valuable marker of normal MC4R function. Recent work has demonstrated a statistical correlation between the efficacy of β-arrestin recruitment to the MC4R and body mass index; however, the data reported here demonstrate both decreased and increased β-arrestin signalling in obesity-associated MC4R mutations.
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Affiliation(s)
- Taneisha Gillyard
- Department of Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN, USA
| | - Katelyn Fowler
- 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
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Neuronal cAMP/PKA Signaling and Energy Homeostasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1090:31-48. [PMID: 30390284 DOI: 10.1007/978-981-13-1286-1_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The brain plays a key role in the regulation of body weight and glucose metabolism. Peripheral signals including hormones, metabolites, and neural afferent signals are received and processed by the brain which in turn elicits proper behavioral and metabolic responses for maintaining energy and glucose homeostasis. The cAMP/protein kinase A (PKA) pathway acts downstream G-protein-coupled receptors (GPCR) to mediate the physiological effects of many hormones and neurotransmitters. Activated PKA phosphorylates various proteins including ion channels, enzymes, and transcription factors and regulates their activity. Recent studies have shown that neuronal cAMP/PKA activity in multiple brain regions are involved in the regulation of feeding, energy expenditure, and glucose homeostasis. In this chapter I summarize recent genetic and pharmacological studies concerning the regulation of body weight and glucose homeostasis by cAMP/PKA signaling in the brain.
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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: 25] [Impact Index Per Article: 5.0] [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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Baldini G, Phelan KD. The melanocortin pathway and control of appetite-progress and therapeutic implications. J Endocrinol 2019; 241:R1-R33. [PMID: 30812013 PMCID: PMC6500576 DOI: 10.1530/joe-18-0596] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 01/22/2019] [Indexed: 12/19/2022]
Abstract
The initial discovery that ob/ob mice become obese because of a recessive mutation of the leptin gene has been crucial to discover the melanocortin pathway to control appetite. In the melanocortin pathway, the fed state is signaled by abundance of circulating hormones such as leptin and insulin, which bind to receptors expressed at the surface of pro-opiomelanocortin (POMC) neurons to promote processing of POMC to the mature hormone α-melanocyte-stimulating hormone (α-MSH). The α-MSH released by POMC neurons then signals to decrease energy intake by binding to melanocortin-4 receptor (MC4R) expressed by MC4R neurons to the paraventricular nucleus (PVN). Conversely, in the 'starved state' activity of agouti-related neuropeptide (AgRP) and of neuropeptide Y (NPY)-expressing neurons is increased by decreased levels of circulating leptin and insulin and by the orexigenic hormone ghrelin to promote food intake. This initial understanding of the melanocortin pathway has recently been implemented by the description of the complex neuronal circuit that controls the activity of POMC, AgRP/NPY and MC4R neurons and downstream signaling by these neurons. This review summarizes the progress done on the melanocortin pathway and describes how obesity alters this pathway to disrupt energy homeostasis. We also describe progress on how leptin and insulin receptors signal in POMC neurons, how MC4R signals and how altered expression and traffic of MC4R change the acute signaling and desensitization properties of the receptor. We also describe how the discovery of the melanocortin pathway has led to the use of melanocortin agonists to treat obesity derived from genetic disorders.
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Affiliation(s)
- Giulia Baldini
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Kevin D. Phelan
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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Yuan XC, Tao YX. Fenoprofen-An Old Drug Rediscovered as a Biased Allosteric Enhancer for Melanocortin Receptors. ACS Chem Neurosci 2019; 10:1066-1074. [PMID: 30168706 DOI: 10.1021/acschemneuro.8b00347] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
It is time-consuming and costly to bring new drugs to market, making it necessary and urgent to exploit existing drugs for new uses. Recently, fenoprofen was demonstrated as an allosteric modulator at melanocortin receptors (MCRs), although the exact mode of action has not been clarified. MCRs regulate multiple functions, including pigmentation, adrenal steroidogenesis, inflammation, energy homeostasis, and exocrine gland secretion. In this study, we showed that fenoprofen failed to displace the orthosteric agonist Nle4-d-Phe7-α-melanocyte stimulating hormone from binding to MC3-5R while possessing positive allosteric modulator activities at these receptors. In addition, fenoprofen induced biased signaling at MC3-5R, as it selectively activated ERK1/2 cascade but not the canonical cAMP signaling. Notably, fenoprofen stimulated biased signaling at MC3-5R, but not at MC1R, hence acting selectively among this highly conserved family of receptors. Moreover, PAM activity and biased signaling induced by fenoprofen were observed not only at wild-type but also at naturally occurring mutant MC3Rs, suggesting that this biased allosteric enhancer action might constitute as novel therapeutic opportunity for obese patients harboring these mutations. Our study might guide novel therapeutic applications for repurposing current drugs or designing new drugs combining allosteric and biased properties.
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Affiliation(s)
- Xiao-Chen Yuan
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, 230036 Anhui, China
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849, United States
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Wang W, Guo DY, Lin YJ, Tao YX. Melanocortin Regulation of Inflammation. Front Endocrinol (Lausanne) 2019; 10:683. [PMID: 31649620 PMCID: PMC6794349 DOI: 10.3389/fendo.2019.00683] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/19/2019] [Indexed: 12/18/2022] Open
Abstract
Adrenocorticotropic hormone (ACTH), and α-, β-, and γ-melanocyte-stimulating hormones (α-, β-, γ-MSH), collectively known as melanocortins, together with their receptors (melanocortin receptors), are components of an ancient modulatory system. The clinical use of ACTH in the treatment of rheumatoid arthritis started in 1949, originally thought that the anti-inflammatory action was through hypothalamus-pituitary-adrenal axis and glucocorticoid-dependent. Subsequent decades have witnessed extensive attempts in unraveling the physiology and pharmacology of the melanocortin system. It is now known that ACTH, together with α-, β-, and γ-MSHs, also possess glucocorticoid-independent anti-inflammatory and immunomodulatory effects by activating the melanocortin receptors expressed in the brain or peripheral immune cells. This review will briefly introduce the melanocortin system and highlight the action of melanocortins in the regulation of immune functions from in vitro, in vivo, preclinical, and clinical studies. The potential therapeutic use of melanocortins are also summarized.
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Affiliation(s)
- Wei Wang
- Department of Clinical Laboratory, Xiamen Huli Guoyu Clinic, Co., Ltd., Xiamen, China
| | - Dong-Yu Guo
- Department of Clinical Laboratory, Xiamen Huli Guoyu Clinic, Co., Ltd., Xiamen, China
- *Correspondence: Dong-Yu Guo
| | - Yue-Jun Lin
- Department of Clinical Laboratory, Xiamen Huli Guoyu Clinic, Co., Ltd., Xiamen, China
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology, and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, United States
- Ya-Xiong Tao
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Heyder N, Kleinau G, Szczepek M, Kwiatkowski D, Speck D, Soletto L, Cerdá-Reverter JM, Krude H, Kühnen P, Biebermann H, Scheerer P. Signal Transduction and Pathogenic Modifications at the Melanocortin-4 Receptor: A Structural Perspective. Front Endocrinol (Lausanne) 2019; 10:515. [PMID: 31417496 PMCID: PMC6685040 DOI: 10.3389/fendo.2019.00515] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 07/15/2019] [Indexed: 12/19/2022] Open
Abstract
The melanocortin-4 receptor (MC4R) can be endogenously activated by binding of melanocyte-stimulating hormones (MSH), which mediates anorexigenic effects. In contrast, the agouti-related peptide (AgRP) acts as an endogenous inverse agonist and suppresses ligand-independent basal signaling activity (orexigenic effects). Binding of ligands to MC4R leads to the activation of different G-protein subtypes or arrestin and concomitant signaling pathways. This receptor is a key protein in the hypothalamic regulation of food intake and energy expenditure and naturally-occurring inactivating MC4R variants are the most frequent cause of monogenic obesity. In general, obesity is a growing problem on a global scale and is of social, medical, and economic relevance. A significant goal is to develop optimized pharmacological tools targeting MC4R without adverse effects. To date, this has not been achieved because of inter alia non-selective ligands across the five functionally different MCR subtypes (MC1-5R). This motivates further investigation of (i) the three-dimensional MC4R structure, (ii) binding mechanisms of various ligands, and (iii) the molecular transfer process of signal transduction, with the aim of understanding how structural features are linked with functional-physiological aspects. Unfortunately, experimentally elucidated structural information is not yet available for the MC receptors, a group of class A G-protein coupled receptors (GPCRs). We, therefore, generated MC4R homology models and complexes with interacting partners to describe approximate structural properties associated with signaling mechanisms. In addition, molecular insights from pathogenic mutations were incorporated to discriminate more precisely their individual malfunction of the signal transfer mechanism.
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Affiliation(s)
- Nicolas Heyder
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Gunnar Kleinau
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- *Correspondence: Gunnar Kleinau
| | - Michal Szczepek
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Dennis Kwiatkowski
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - David Speck
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Lucia Soletto
- Departamento de Fisiología de Peces y Biotecnología, Consejo Superior de Investigaciones Científicas, Instituto de Acuicultura Torre de la Sal, Ribera de Cabanes, Spain
| | - José Miguel Cerdá-Reverter
- Departamento de Fisiología de Peces y Biotecnología, Consejo Superior de Investigaciones Científicas, Instituto de Acuicultura Torre de la Sal, Ribera de Cabanes, Spain
| | - Heiko Krude
- Institute of Experimental Pediatric Endocrinology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Peter Kühnen
- Institute of Experimental Pediatric Endocrinology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Patrick Scheerer
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Patrick Scheerer
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Causes and solutions to “globesity”: The new fa(s)t alarming global epidemic. Food Chem Toxicol 2018; 121:173-193. [DOI: 10.1016/j.fct.2018.08.071] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 08/10/2018] [Accepted: 08/29/2018] [Indexed: 12/12/2022]
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Lensing CJ, Freeman KT, Schnell SM, Speth RC, Zarth AT, Haskell-Luevano C. Developing a Biased Unmatched Bivalent Ligand (BUmBL) Design Strategy to Target the GPCR Homodimer Allosteric Signaling (cAMP over β-Arrestin 2 Recruitment) Within the Melanocortin Receptors. J Med Chem 2018; 62:144-158. [PMID: 29669202 DOI: 10.1021/acs.jmedchem.8b00238] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Understanding the functional relevance of G protein-coupled receptor (GPCR) homodimerization has been limited by the insufficient tools to assess asymmetric signaling occurring within dimers comprised of the same receptor type. We present unmatched bivalent ligands (UmBLs) to study the asymmetric function of melanocortin homodimers. UmBLs contain one agonist and one antagonist pharmacophore designed to target a melanocortin homodimer such that one receptor is occupied by an agonist and the other receptor by an antagonist pharmacophore. First-in-class biased UmBLs (BUmBLs) targeting the human melanocortin-4 receptor (hMC4R) were discovered. The BUmBLs displayed biased agonism by potently stimulating cAMP signaling (EC50 ∼ 2-6 nM) but minimally activating the β-arrestin recruitment pathway (≤55% maximum signal at 10 μM). To our knowledge, we report the first single-compound strategy to pharmacologically target melanocortin receptor allosteric signaling that occurs between homodimers that can be applied straightforwardly in vitro and in vivo to other GPCR systems.
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Affiliation(s)
- Cody J Lensing
- Department of Medicinal Chemistry and Institute for Translational Neuroscience , University of Minnesota , 308 Harvard Street SE , Minneapolis , Minnesota 55455 , United States
| | - Katie T Freeman
- Department of Medicinal Chemistry and Institute for Translational Neuroscience , University of Minnesota , 308 Harvard Street SE , Minneapolis , Minnesota 55455 , United States
| | - Sathya M Schnell
- Department of Medicinal Chemistry and Institute for Translational Neuroscience , University of Minnesota , 308 Harvard Street SE , Minneapolis , Minnesota 55455 , United States
| | - Robert C Speth
- College of Pharmacy , Nova Southeastern University , Fort Lauderdale , Florida 33328-2018 , United States.,Department of Pharmacology and Physiology , Georgetown University , Washington, D.C. 20057 , United States
| | - Adam T Zarth
- Department of Medicinal Chemistry and Institute for Translational Neuroscience , University of Minnesota , 308 Harvard Street SE , Minneapolis , Minnesota 55455 , United States.,Masonic Cancer Center , University of Minnesota , 2231 Sixth Street SE, 2-210 CCRB , Minneapolis , Minnesota 55455 , United States
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry and Institute for Translational Neuroscience , University of Minnesota , 308 Harvard Street SE , Minneapolis , Minnesota 55455 , United States
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Morselli LL, Claflin KE, Cui H, Grobe JL. Control of Energy Expenditure by AgRP Neurons of the Arcuate Nucleus: Neurocircuitry, Signaling Pathways, and Angiotensin. Curr Hypertens Rep 2018; 20:25. [PMID: 29556733 DOI: 10.1007/s11906-018-0824-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE OF REVIEW Here, we review the current understanding of the functional neuroanatomy of neurons expressing Agouti-related peptide (AgRP) and the angiotensin 1A receptor (AT1A) within the arcuate nucleus (ARC) in the control of energy balance. RECENT FINDINGS The development and maintenance of obesity involves suppression of resting metabolic rate (RMR). RMR control is integrated via AgRP and proopiomelanocortin neurons within the ARC. Their projections to other hypothalamic and extrahypothalamic nuclei contribute to RMR control, though relatively little is known about the contributions of individual projections and the neurotransmitters involved. Recent studies highlight a role for AT1A, localized to AgRP neurons, but the specific function of AT1A within these cells remains unclear. AT1A functions within AgRP neurons to control RMR, but additional work is required to clarify its role within subpopulations of AgRP neurons projecting to distinct second-order nuclei, and the molecular mediators of its signaling within these cells.
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Affiliation(s)
- Lisa L Morselli
- Department of Pharmacology, University of Iowa, 51 Newton Rd., 2-307 BSB, Iowa City, IA, 52242, USA.,Department of Internal Medicine, Division of Endocrinology, University of Iowa, Iowa City, IA, 52242, USA
| | - Kristin E Claflin
- Department of Pharmacology, University of Iowa, 51 Newton Rd., 2-307 BSB, Iowa City, IA, 52242, USA
| | - Huxing Cui
- Department of Pharmacology, University of Iowa, 51 Newton Rd., 2-307 BSB, Iowa City, IA, 52242, USA.,Center for Hypertension Research, University of Iowa, Iowa City, IA, 52242, USA.,Obesity Research & Education Initiative, University of Iowa, Iowa City, IA, 52242, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, 52242, USA.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, 52242, USA.,Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA, 52242, USA
| | - Justin L Grobe
- Department of Pharmacology, University of Iowa, 51 Newton Rd., 2-307 BSB, Iowa City, IA, 52242, USA. .,Center for Hypertension Research, University of Iowa, Iowa City, IA, 52242, USA. .,Obesity Research & Education Initiative, University of Iowa, Iowa City, IA, 52242, USA. .,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, 52242, USA. .,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, 52242, USA. .,Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA, 52242, USA.
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Yang LK, Tao YX. Biased signaling at neural melanocortin receptors in regulation of energy homeostasis. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2486-2495. [PMID: 28433713 DOI: 10.1016/j.bbadis.2017.04.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/09/2017] [Accepted: 04/10/2017] [Indexed: 12/15/2022]
Abstract
The global prevalence of obesity highlights the importance of understanding on regulation of energy homeostasis. The central melanocortin system is an important intersection connecting the neural pathways controlling satiety and energy expenditure to regulate energy homeostasis by sensing and integrating the signals of external stimuli. In this system, neural melanocortin receptors (MCRs), melanocortin-3 and -4 receptors (MC3R and MC4R), play crucial roles in the regulation of energy homeostasis. Recently, multiple intracellular signaling pathways and biased signaling at neural MCRs have been discovered, providing new insights into neural MCR signaling. This review attempts to summarize biased signaling including biased receptor mutants (both naturally occurring and lab-generated) and biased ligands at neural MCRs, and to provide a better understanding of obesity pathogenesis and new therapeutic implications for obesity treatment.
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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
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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Demidowich AP, Jun JY, Yanovski JA. Polymorphisms and mutations in the melanocortin-3 receptor and their relation to human obesity. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2468-2476. [PMID: 28363697 DOI: 10.1016/j.bbadis.2017.03.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 03/23/2017] [Accepted: 03/27/2017] [Indexed: 12/18/2022]
Abstract
Inactivating mutations in the melanocortin 3 receptor (Mc3r) have been described as causing obesity in mice, but the physiologic effects of MC3R mutations in humans have been less clear. Here we review the MC3R polymorphisms and mutations identified in humans, and the in vitro, murine, and human cohort studies examining their putative effects. Some, but not all, studies suggest that the common human MC3R variant T6K+V81I, as well as several other rare, function-altering mutations, are associated with greater adiposity and hyperleptinemia with altered energy partitioning. In vitro, the T6K+V81I variant appears to decrease MC3R expression and therefore cAMP generation in response to ligand binding. Knockin mouse studies confirm that the T6K+V81I variant increases feeding efficiency and the avidity with which adipocytes derived from bone or adipose tissue stem cells store triglycerides. Other MC3R mutations occur too infrequently in the human population to make definitive conclusions regarding their clinical effects. This article is part of a Special Issue entitled: Melanocortin Receptors - edited by Ya-Xiong Tao.
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Affiliation(s)
- Andrew P Demidowich
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Joo Yun Jun
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Jack A Yanovski
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States.
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