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Ng TF, Cho JY, Zhao JL, Gardiner JR, Wang ES, Leung E, Xu Z, Fineman SL, Lituchy M, Lo AC, Taylor AW. Alpha-Melanocyte-Stimulating Hormone Maintains Retinal Homeostasis after Ischemia/Reperfusion. Biomolecules 2024; 14:525. [PMID: 38785932 PMCID: PMC11118772 DOI: 10.3390/biom14050525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024] Open
Abstract
Augmenting the natural melanocortin pathway in mouse eyes with uveitis or diabetes protects the retinas from degeneration. The retinal cells are protected from oxidative and apoptotic signals of death. Therefore, we investigated the effects of a therapeutic application of the melanocortin alpha-melanocyte-stimulating hormone (α-MSH) on an ischemia and reperfusion (I/R) model of retinal degenerative disease. Eyes were subjected to an I/R procedure and were treated with α-MSH. Retinal sections were histopathologically scored. Also, the retinal sections were immunostained for viable ganglion cells, activated Muller cells, microglial cells, and apoptosis. The I/R caused retinal deformation and ganglion cell loss that was significantly reduced in I/R eyes treated with α-MSH. While α-MSH treatment marginally reduced the number of GFAP-positive Muller cells, it significantly suppressed the density of Iba1-positive microglial cells in the I/R retinas. Within one hour after I/R, there was apoptosis in the ganglion cell layer, and by 48 h, there was apoptosis in all layers of the neuroretina. The α-MSH treatment significantly reduced and delayed the onset of apoptosis in the retinas of I/R eyes. The results demonstrate that therapeutically augmenting the melanocortin pathways preserves retinal structure and cell survival in eyes with progressive neuroretinal degenerative disease.
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Affiliation(s)
- Tat Fong Ng
- Department of Ophthalmology, Boston University Chobanian & Avedesian School of Medicine, Boston, MA 02118, USA; (T.F.N.)
| | - Jenna Y. Cho
- Department of Ophthalmology, Boston University Chobanian & Avedesian School of Medicine, Boston, MA 02118, USA; (T.F.N.)
| | - John L. Zhao
- Department of Ophthalmology, Boston University Chobanian & Avedesian School of Medicine, Boston, MA 02118, USA; (T.F.N.)
| | - John R. Gardiner
- Department of Ophthalmology, Boston University Chobanian & Avedesian School of Medicine, Boston, MA 02118, USA; (T.F.N.)
| | - Eric S. Wang
- Department of Ophthalmology, Boston University Chobanian & Avedesian School of Medicine, Boston, MA 02118, USA; (T.F.N.)
| | - Elman Leung
- Department of Ophthalmology, Boston University Chobanian & Avedesian School of Medicine, Boston, MA 02118, USA; (T.F.N.)
| | - Ziqian Xu
- Department of Ophthalmology, Boston University Chobanian & Avedesian School of Medicine, Boston, MA 02118, USA; (T.F.N.)
| | - Samantha L. Fineman
- Department of Ophthalmology, Boston University Chobanian & Avedesian School of Medicine, Boston, MA 02118, USA; (T.F.N.)
| | - Melinda Lituchy
- Department of Ophthalmology, Boston University Chobanian & Avedesian School of Medicine, Boston, MA 02118, USA; (T.F.N.)
| | - Amy C. Lo
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Andrew W. Taylor
- Department of Ophthalmology, Boston University Chobanian & Avedesian School of Medicine, Boston, MA 02118, USA; (T.F.N.)
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Kardas Yildiz A, Bulbul A, Ozer Bekmez B, Turkyilmaz A, Terali K, Dagdeviren Cakir A, Ucar A. A Rare Presentation of Homozygous Pathogenic Variant in MC2R Gene with Salt-Wasting Crisis in a Neonate. Mol Syndromol 2024; 15:77-82. [PMID: 38357256 PMCID: PMC10862318 DOI: 10.1159/000533986] [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: 04/26/2023] [Accepted: 09/02/2023] [Indexed: 02/16/2024] Open
Abstract
Introduction Familial glucocorticoid deficiency (FGD) is a rare autosomal recessive disease resulting from isolated glucocorticoid deficiency or unresponsiveness to adrenocorticotropic hormone. Patients with FGD usually present in infancy or early childhood with hyperpigmentation, recurrent infections, and hypoglycemia. The salt-wasting crisis is rare. Case Presentation A term female neonate was admitted to the neonatal intensive care unit due to respiratory distress. On physical examination, she had generalized hyperpigmentation. Initial laboratory work-up yielded normal serum electrolytes and glucose. Hyponatremia and hyperkalemia emerged on follow-up. The patient was diagnosed as having primary adrenal insufficiency (PAI) with elevated plasma adrenocorticotropin hormone and reduced cortisol levels and hydrocortisone. We started on oral sodium (5 mEq/kg/day) and fludrocortisone (FC) (0.2 mg/day) treatment to the patient. Ultrasonography revealed hypoplastic adrenal glands. Molecular genetic analysis revealed a previously reported homozygous pathogenic variant NM_000529.2: c.560delT (p.V187fs*29) in the MC2R gene. FC dose was tapered to 0.05 mg/day on the third month of life and was stopped at tenth months of age with maintenance of normal serum electrolytes and clinical findings. Conclusion FGD due to MC2R gene mutation may rarely present with a salt-wasting crisis in the neonatal period. Identifying the causative gene with the pathogenic variant in PAI may serve to individualize a treatment plan.
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Affiliation(s)
- Aysenur Kardas Yildiz
- Department of Pediatrics, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
| | - Ali Bulbul
- Department of Neonatology, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
| | - Buse Ozer Bekmez
- Department of Neonatology, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
| | - Ayberk Turkyilmaz
- Department of Medical Genetics, Karadeniz Technical University Faculty of Medicine, Trabzon, Turkey
| | - Kerem Terali
- Department of Medical Biochemistry, Cyprus International University Faculty of Medicine, Nicosia, Cyprus
| | - Aydilek Dagdeviren Cakir
- Department of Pediatric Endocrinology, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
| | - Ahmet Ucar
- Department of Pediatric Endocrinology, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
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3
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Bouyoucos IA, Shaughnessy CA, Gary Anderson W, Dores RM. Molecular and pharmacological analysis of the melanocortin-2 receptor and its accessory proteins Mrap1 and Mrap2 in a Squalomorph shark, the Pacific spiny dogfish. Gen Comp Endocrinol 2023; 342:114342. [PMID: 37454980 DOI: 10.1016/j.ygcen.2023.114342] [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: 03/30/2023] [Revised: 07/08/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023]
Abstract
The hypothalamus-pituitary-adrenal/interrenal (HPA/I) axis is a conserved vertebrate neuroendocrine mechanism regulating the stress response. The penultimate step of the HPA/I axis is the exclusive activation of the melanocortin-2 receptor (Mc2r) by adrenocorticotropic hormone (ACTH), requiring an accessory protein, Mrap1 or Mrap2. Limited data for only three cartilaginous fishes support the hypothesis that Mc2r/Mrap1 function in bony vertebrates is a derived trait. Further, Mc2r/Mrap1 functional properties appear to contrast among cartilaginous fishes (i.e., the holocephalans and elasmobranchs). This study sought to determine whether functional properties of Mc2r/Mrap1 are conserved across elasmobranchs and in contrast to holocephalans. The deduced amino acid sequences of Pacific spiny dogfish (Squalus suckleyi; pd) pdMc2r, pdMrap1, and pdMrap2 were obtained from a de novo transcriptome of the interrenal gland and validated against the S. suckleyi genome. pdMc2r showed high primary sequence similarity with elasmobranch and holocephalan Mc2r except at extracellular domains 1 and 2, and transmembrane domain 5. pdMraps showed similarly high sequence similarity with holocephalan and other elasmobranch Mraps, with all cartilaginous fish Mrap1 orthologs lacking an activation motif. cAMP reporter gene assays demonstrated that pdMc2r requires an Mrap for activation, and can be activated by stingray (sr) ACTH(1-24), srACTH(1-13)NH2 (i.e., α-MSH), and γ-melanocyte-stimulating hormone at physiological concentrations. However, pdMc2r was three orders of magnitude more sensitive to srACTH(1-24) than srACTH(1-13)NH2. Further, pdMc2r was two orders of magnitude more sensitive to srACTH(1-24) when expressed with pdMrap1 than with pdMrap2. These data suggest that functional properties of pdMc2r/pdMrap1 reflect other elasmobranchs and contrast what is seen in holocephalans.
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Affiliation(s)
- Ian A Bouyoucos
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; Bamfield Marine Sciences Centre, Bamfield, BC V0R 1B0, Canada.
| | | | - W Gary Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; Bamfield Marine Sciences Centre, Bamfield, BC V0R 1B0, Canada
| | - Robert M Dores
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
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Gebrie A. The melanocortin receptor signaling system and its role in neuroprotection against neurodegeneration: Therapeutic insights. Ann N Y Acad Sci 2023; 1527:30-41. [PMID: 37526975 DOI: 10.1111/nyas.15048] [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] [Indexed: 08/02/2023]
Abstract
The melanocortin signaling system consists of the melanocortin peptides, their distinctive receptors, accessory proteins, and endogenous antagonists. Melanocortin peptides are small peptide hormones that have been studied in a variety of physiological and pathological conditions. There are five types of melanocortin receptors, and they are distributed within the central nervous system and in several tissues of the periphery. The G protein-coupled melanocortin receptors typically signal through adenylyl cyclase and other downstream signaling pathways. Depending on the ligand, surface expression of melanocortin receptor, receptor occupancy period, related proteins, the type of cell, and other parameters, the signaling pathways are complicated and pleiotropic. While it is known that all five melanocortin receptors are coupled to Gs, they can also occasionally couple to Gq or Gi. Both direct and indirect neuroprotection are induced by the melanocortin signaling system. Targeting several of the components of the melanocortin signaling system (ligands, receptors, accessory proteins, signaling effectors, and regulators) may provide therapeutic opportunities. Activation of the melanocortin system improves different functional traits in neurodegenerative diseases. There is a potential for additional melanocortin system interventions by interfering with dimerization or dissociation. This review aims to discuss the melanocortin receptor signaling system and its role in neuroprotection, as well as its therapeutic potential.
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Affiliation(s)
- Alemu Gebrie
- Department of Biomedical Sciences, School of Medicine, Debre Markos University, Debre Markos, Ethiopia
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5
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Bernard A, Ojeda Naharros I, Yue X, Mifsud F, Blake A, Bourgain-Guglielmetti F, Ciprin J, Zhang S, McDaid E, Kim K, Nachury MV, Reiter JF, Vaisse C. MRAP2 regulates energy homeostasis by promoting primary cilia localization of MC4R. JCI Insight 2023; 8:e155900. [PMID: 36692018 PMCID: PMC9977312 DOI: 10.1172/jci.insight.155900] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 11/30/2022] [Indexed: 01/24/2023] Open
Abstract
The G protein-coupled receptor melanocortin-4 receptor (MC4R) and its associated protein melanocortin receptor-associated protein 2 (MRAP2) are essential for the regulation of food intake and body weight in humans. MC4R localizes and functions at the neuronal primary cilium, a microtubule-based organelle that senses and relays extracellular signals. Here, we demonstrate that MRAP2 is critical for the weight-regulating function of MC4R neurons and the ciliary localization of MC4R. More generally, our study also reveals that GPCR localization to primary cilia can require specific accessory proteins that may not be present in heterologous cell culture systems. Our findings further demonstrate that targeting of MC4R to neuronal primary cilia is essential for the control of long-term energy homeostasis and suggest that genetic disruption of MC4R ciliary localization may frequently underlie inherited forms of obesity.
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Affiliation(s)
| | | | - Xinyu Yue
- Department of Medicine and The Diabetes Center
| | | | - Abbey Blake
- Department of Medicine and The Diabetes Center
| | | | | | - Sumei Zhang
- Department of Medicine and The Diabetes Center
| | - Erin McDaid
- Department of Medicine and The Diabetes Center
| | - Kellan Kim
- Department of Medicine and The Diabetes Center
| | | | - Jeremy F. Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, UCSF, San Francisco, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
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6
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Luo P, Feng W, Ma S, Dai A, Wu K, Chen X, Yuan Q, Cai X, Yang D, Wang MW, Eric Xu H, Jiang Y. Structural basis of signaling regulation of the human melanocortin-2 receptor by MRAP1. Cell Res 2023; 33:46-54. [PMID: 36588120 PMCID: PMC9810661 DOI: 10.1038/s41422-022-00751-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 11/08/2022] [Indexed: 01/03/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are regulated by various downstream proteins, of which the melanocortin receptor accessory protein 1 (MRAP1) is closely involved in the regulation of melanocortin receptor 2 (MC2R). Assisted by MRAP1, MC2R responds to adrenocorticotropic hormone (ACTH) and stimulates glucocorticoid biogenesis and cortisol secretion. MC2R activation plays an essential role in the hypothalamic-pituitary-adrenal (HPA) axis that regulates stress response, while its dysfunction causes glucocorticoid insufficiency- or cortisol excess-associated disorders. Here, we present a cryo-electron microscopy (cryo-EM) structure of the ACTH-bound MC2R-Gs-MRAP1 complex. Our structure, together with mutagenesis analysis, reveals a unique sharp kink at the extracellular region of MRAP1 and the 'seat-belt' effect of MRAP1 on stabilizing ACTH binding and MC2R activation. Mechanisms of ACTH recognition by MC2R and receptor activation are also demonstrated. These findings deepen our understanding of GPCR regulation by accessory proteins and provide valuable insights into the ab initio design of therapeutic agents targeting MC2R.
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Affiliation(s)
- Ping Luo
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Wenbo Feng
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Shanshan Ma
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Antao Dai
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Kai Wu
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xianyue Chen
- Research Center for Deepsea Bioresources, Sanya, Hainan, China
| | - Qingning Yuan
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xiaoqing Cai
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Dehua Yang
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- Research Center for Deepsea Bioresources, Sanya, Hainan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ming-Wei Wang
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
- Research Center for Deepsea Bioresources, Sanya, Hainan, China.
- University of Chinese Academy of Sciences, Beijing, China.
| | - H Eric Xu
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
- University of Chinese Academy of Sciences, Beijing, China.
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
| | - Yi Jiang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
- Lingang Laboratory, Shanghai, China.
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7
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Yin TC, Mittal A, Buscaglia P, Li W, Sebag JA. Activation of amygdala prokineticin receptor 2 neurons drives the anorexigenic activity of the neuropeptide PK2. J Biol Chem 2022; 299:102814. [PMID: 36539034 PMCID: PMC9860486 DOI: 10.1016/j.jbc.2022.102814] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/09/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Energy homeostasis is a complex system involving multiple hormones, neuropeptides, and receptors. Prokineticins (PK1 and PK2) are agonists to two G protein-coupled receptors, prokineticin receptor 1 and 2 (PKR1 and PKR2), which decrease food intake when injected in rodents. The relative contribution of PKR1 and PKR2 to the anorexigenic effect of PK2 and their site of action in the brain have not yet been elucidated. While PKR1 and PKR2 are both expressed in the hypothalamus, a central region involved in the control of energy homeostasis, PKR2 is also present in the amygdala, which has recently been shown to regulate food intake in response to several anorexigenic signals. PKR trafficking and signaling are inhibited by the melanocortin receptor accessory protein 2 (MRAP2), thus suggesting that MRAP2 has the potential to alter the anorexigenic activity of PK2 in vivo. In this study, we investigated the importance of PKR1 and PKR2 for PK2-mediated inhibition of food intake, the brain region involved in this function, and the effect of MRAP2 on PK2 action in vivo. Using targeted silencing of PKR2 and chemogenetic manipulation of PKR2 neurons, we show that the anorexigenic effect of PK2 is mediated by PKR2 in the amygdala and that altering MRAP2 expression in PKR2 neurons modulates the activity of PK2. Collectively, our results provide evidence that inhibition of food intake by PKs is not mediated through activation of hypothalamic neurons but rather amygdala PKR2 neurons and further establishes the importance of MRAP2 in the regulation of energy homeostasis.
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Affiliation(s)
- Terry C. Yin
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA,Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA,Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, USA
| | - Ayushi Mittal
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA,Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA,Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, USA
| | - Paul Buscaglia
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA,Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA,Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, USA
| | - Wenxian Li
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA,Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA,Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, USA
| | - Julien A. Sebag
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA,Fraternal Order of Eagle Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA,Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA,Pappajohn Biomedical Institute, University of Iowa, Iowa City, Iowa, USA,For correspondence: Julien A. Sebag
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8
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Brewer KM, Brewer KK, Richardson NC, Berbari NF. Neuronal cilia in energy homeostasis. Front Cell Dev Biol 2022; 10:1082141. [PMID: 36568981 PMCID: PMC9773564 DOI: 10.3389/fcell.2022.1082141] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 11/11/2022] [Indexed: 12/13/2022] Open
Abstract
A subset of genetic disorders termed ciliopathies are associated with obesity. The mechanisms behind cilia dysfunction and altered energy homeostasis in these syndromes are complex and likely involve deficits in both development and adult homeostasis. Interestingly, several cilia-associated gene mutations also lead to morbid obesity. While cilia have critical and diverse functions in energy homeostasis, including their roles in centrally mediated food intake and peripheral tissues, many questions remain. Here, we briefly discuss syndromic ciliopathies and monogenic cilia signaling mutations associated with obesity. We then focus on potential ways neuronal cilia regulate energy homeostasis. We discuss the literature around cilia and leptin-melanocortin signaling and changes in ciliary G protein-coupled receptor (GPCR) signaling. We also discuss the different brain regions where cilia are implicated in energy homeostasis and the potential for cilia dysfunction in neural development to contribute to obesity. We close with a short discussion on the challenges and opportunities associated with studies looking at neuronal cilia and energy homeostasis. This review highlights how neuronal cilia-mediated signaling is critical for proper energy homeostasis.
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Affiliation(s)
- Kathryn M. Brewer
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Katlyn K. Brewer
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Nicholas C. Richardson
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Nicolas F. Berbari
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
- Stark Neurosciences Research Institute, Indiana University, Indianapolis, IN, United States
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN, United States
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9
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Zhang X, Su J, Huang T, Wang X, Wu C, Li J, Li J, Zhang J, Wang Y. Characterization of the chicken melanocortin 5 receptor and its potential role in regulating hepatic glucolipid metabolism. Front Physiol 2022; 13:917712. [PMID: 36277187 PMCID: PMC9583845 DOI: 10.3389/fphys.2022.917712] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 09/16/2022] [Indexed: 11/18/2022] Open
Abstract
Melanocortin receptors (MC1R-MC5R) and their accessory proteins (MRAPs) are involved in a variety of physiological processes, including pigmentation, lipolysis, adrenal steroidogenesis, and immunology. However, the physiological roles of MC5R are rarely characterized in vertebrates, particularly in birds. In this work, we cloned the full-length cDNA of chicken MC5R and identified its core promoter region. Functional studies revealed that cMC5R was more sensitive to ACTH/α-MSH than β-MSH/γ-MSH, and was coupled to the cAMP/PKA signaling pathway. We demonstrated that MRAP2 decreased MC5R sensitivity to α-MSH, whereas MRAP1 did not have a similar effect, and that both MRAPs significantly reduced MC5R expression on the cell membrane surface. Transcriptome and qPCR data showed that both MRAP1 and MC5R were highly expressed in chicken liver. Additionally, we observed that ACTH might increase hepatic glucose production and decrease lipogenesis in primary hepatocytes, and dose-dependently downregulated the expression levels of ELOVL6 and THRSPA genes. These findings indicated that ACTH may act directly on hepatocytes to regulate glucolipid metabolism, which will help to understand the function of MC5R in avian.
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Affiliation(s)
- Xiao Zhang
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, College of Life Sciences, Sichuan University, Chengdu, China
| | - Jiancheng Su
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, College of Life Sciences, Sichuan University, Chengdu, China
| | - Tianjiao Huang
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, College of Life Sciences, Sichuan University, Chengdu, China
| | - Xinglong Wang
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, College of Life Sciences, Sichuan University, Chengdu, China
| | - Chenlei Wu
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, College of Life Sciences, Sichuan University, Chengdu, China
| | - Jing Li
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, College of Life Sciences, Sichuan University, Chengdu, China
| | - Juan Li
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, College of Life Sciences, Sichuan University, Chengdu, China
| | - Jiannan Zhang
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, College of Life Sciences, Sichuan University, Chengdu, China
| | - Yajun Wang
- Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, College of Life Sciences, Sichuan University, Chengdu, China
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10
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Rouault AAJ, Buscaglia P, Sebag JA. MRAP2 inhibits β-arrestin recruitment to the ghrelin receptor by preventing GHSR1a phosphorylation. J Biol Chem 2022; 298:102057. [PMID: 35605660 PMCID: PMC9190059 DOI: 10.1016/j.jbc.2022.102057] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 11/19/2022] Open
Abstract
The melanocortin receptor accessory protein 2 (MRAP2) is essential for several physiological functions of the ghrelin receptor growth hormone secretagogue receptor 1a (GHSR1a), including increasing appetite and suppressing insulin secretion. In the absence of MRAP2, GHSR1a displays high constitutive activity and a weak G-protein-mediated response to ghrelin and readily recruits β-arrestin. In the presence of MRAP2, however, G-protein-mediated signaling via GHSR1a is strongly dependent on ghrelin stimulation and the recruitment of β-arrestin is significantly diminished. To better understand how MRAP2 modifies GHSR1a signaling, here we investigated the role of several phosphorylation sites within the C-terminal tail and third intracellular loop of GHSR1a, as well as the mechanism behind MRAP2-mediated inhibition of β-arrestin recruitment. We show that Ser252 and Thr261 in the third intracellular loop of GHSR1a contribute to β-arrestin recruitment, whereas the C-terminal region is not essential for β-arrestin interaction. Additionally, we found that MRAP2 inhibits GHSR1a phosphorylation by blocking the interaction of GRK2 and PKC with the receptor. Taken together, these data suggest that MRAP2 alters GHSR1a signaling by directly impacting the phosphorylation state of the receptor and that the C-terminal tail of GHSR1a prevents rather than contribute to β-arrestin recruitment.
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Affiliation(s)
- Alix A J Rouault
- Department of Molecular Physiology and Biophysics, University of Iowa, Carver College of Medicine, Iowa City, Iowa, USA; F.O.E.D.R.C, Iowa City, Iowa, USA; Pappajohn Biomedical Institute, Iowa City, Iowa, USA; Iowa Neuroscience Institute, Iowa City, Iowa, USA
| | - Paul Buscaglia
- Department of Molecular Physiology and Biophysics, University of Iowa, Carver College of Medicine, Iowa City, Iowa, USA; F.O.E.D.R.C, Iowa City, Iowa, USA; Pappajohn Biomedical Institute, Iowa City, Iowa, USA; Iowa Neuroscience Institute, Iowa City, Iowa, USA
| | - Julien A Sebag
- Department of Molecular Physiology and Biophysics, University of Iowa, Carver College of Medicine, Iowa City, Iowa, USA; F.O.E.D.R.C, Iowa City, Iowa, USA; Pappajohn Biomedical Institute, Iowa City, Iowa, USA; Iowa Neuroscience Institute, Iowa City, Iowa, USA.
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11
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Wang M, Zhai Y, Lei X, Xu J, Jiang B, Kuang Z, Zhang C, Liu S, Bian S, Yang XM, Zan T, Jin LN, Li Q, Zhang C. Determination of the Interaction and Pharmacological Modulation of MCHR1 Signaling by the C-Terminus of MRAP2 Protein. Front Endocrinol (Lausanne) 2022; 13:848728. [PMID: 35311242 PMCID: PMC8931191 DOI: 10.3389/fendo.2022.848728] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 02/07/2022] [Indexed: 11/15/2022] Open
Abstract
Melanin concentrating hormone (MCH), an orexigenic neuropeptide, is primarily secreted by the hypothalamus and acts on its receptor, the melanin-concentrating hormone receptor 1 (MCHR1), to regulate appetite and energy homeostasis. The Melanocortin Receptor Accessory Protein 2 (MRAP2), a small single transmembrane protein broadly expressed in multiple tissues, has been defined as a vital endocrine modulator of five melanocortin receptors (MC1R-MC5R) and several other GPCRs in the regulation of central neuronal activities and peripheral energy balance. Here, we demonstrated the interaction between MRAP2 and MCHR1 by immunoprecipitation and bimolecular fluorescent assay and found that MRAP2 could inhibit MCHR1 signaling in vitro. A series of functional truncations of different regions further identified that the C-terminal domains of MRAP2 protein were required for the pharmacological modulation of intracellular Ca2+ coupled cascades and membrane transport. These findings elucidated the broad regulatory profile of MRAP2 protein in the central nervous system and may provide implications for the modulation of central MCHR1 function in vivo.
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Affiliation(s)
- Meng Wang
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yue Zhai
- Fundamental Research Center, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xiaowei Lei
- Fundamental Research Center, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jing Xu
- Fundamental Research Center, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Bopei Jiang
- Fundamental Research Center, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Zhe Kuang
- Fundamental Research Center, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Cong Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shangyun Liu
- Department of Hematology, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Shan Bian
- Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xiao-Mei Yang
- Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Tao Zan
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- *Correspondence: Tao Zan, ; Li-Na Jin, ; Qingfeng Li, ; Chao Zhang,
| | - Li-Na Jin
- Department of Hematology, Changzheng Hospital, Naval Medical University, Shanghai, China
- *Correspondence: Tao Zan, ; Li-Na Jin, ; Qingfeng Li, ; Chao Zhang,
| | - Qingfeng Li
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- *Correspondence: Tao Zan, ; Li-Na Jin, ; Qingfeng Li, ; Chao Zhang,
| | - Chao Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- *Correspondence: Tao Zan, ; Li-Na Jin, ; Qingfeng Li, ; Chao Zhang,
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12
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Ji RL, Huang L, Wang Y, Liu T, Fan SY, Tao M, Tao YX. Topmouth culter melanocortin-3 receptor: regulation by two isoforms of melanocortin-2 receptor accessory protein 2. Endocr Connect 2021; 10:1489-1501. [PMID: 34678761 PMCID: PMC8630771 DOI: 10.1530/ec-21-0459] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 10/22/2021] [Indexed: 12/11/2022]
Abstract
Melanocortin-3 receptor (MC3R) is a regulator of energy homeostasis, and interaction of MC3R and melanocortin-2 receptor accessory protein 2 (MRAP2) plays a critical role in MC3R signaling of mammals. However, the physiological roles of MC3R in teleosts are not well understood. In this study, qRT-PCR was used to measure gene expression. Radioligand binding assay was used to study the binding properties of topmouth culter MC3R (caMC3R). Intracellular cAMP generation was determined by RIA, and caMC3R expression was quantified with flow cytometry. We showed that culter mc3r had higher expression in the CNS. All agonists could bind and stimulate caMC3R to increase dose dependently intracellular cAMP accumulation. Compared to human MC3R, culter MC3R showed higher constitutive activity, higher efficacies, and Rmax to alpha-melanocyte-stimulating hormone (α-MSH), des-α-MSH, and adrenocorticotrophic hormone. Both caMRAP2a and caMRAP2b markedly decreased caMC3R basal cAMP production. However, only caMRAP2a significantly decreased cell surface expression, Bmax, and Rmax of caMC3R. Expression analysis suggested that MRAP2a and MRAP2b might be more important in regulating MC3R/MC4R signaling during larval period, and reduced mc3r, mc4r, and pomc expression might be primarily involved in modulation of MC3R/MC4R in adults. These data indicated that the cloned caMC3R was a functional receptor. MRAP2a and MRAP2b had different effects on expression and signaling of caMC3R. In addition, expression analysis suggested that MRAP2s, receptors, and hormones might play different roles in regulating culter development and growth.
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Affiliation(s)
- Ren-Lei Ji
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Lu Huang
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, Hunan, People’s Republic of China
| | - Yin Wang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Ting Liu
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Si-Yu Fan
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, Hunan, People’s Republic of China
| | - Min Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, Hunan, People’s Republic of China
- Correspondence should be addressed to M Tao or Y-X Tao: or
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
- Correspondence should be addressed to M Tao or Y-X Tao: or
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13
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Etchevers L, Belotti EM, Díaz PU, Rodríguez FM, Rey F, Salvetti NR, Ortega HH, Amweg AN. MC2R/MRAP2 activation could affect bovine ovarian steroidogenesis potential after ACTH treatment. Theriogenology 2021; 174:102-113. [PMID: 34425302 DOI: 10.1016/j.theriogenology.2021.08.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 08/13/2021] [Accepted: 08/16/2021] [Indexed: 01/10/2023]
Abstract
Stressors activate the hypothalamic-pituitary-adrenal (HPA) axis, reducing fertility by interfering with the mechanisms that regulate the timing of events within the follicular phase of the estrous cycle. In the HPA axis, melanocortin 2 receptor (MC2R) mediates responses to adrenocorticotropic hormone (ACTH) in concert with melanocortin receptor accessory protein 2 (MRAP2). The aims of the present study were: (1) to evaluate the effects of ACTH administered in cows in the preovulatory period on the expression of the MC2R/MRAP2 complex in the dominant follicle; and (2) to analyze the involvement of Extracellular signal Regulated Kinase 1 (ERK1) signaling in the activation of MC2R and the expression of key enzymes involved in the biosynthesis of glucocorticoids (GCs) in the dominant follicle. To this end, 100 IU ACTH was administered to Holstein cows from a local dairy farm during pro-estrus every 12 h for four days until ovariectomy, which was performed before ovulation. Protein immunostaining of MC2R was higher in the dominant follicles of ACTH-treated cows (p < 0.05). Also, Western blot analysis showed higher activation of the ERK1 signaling pathway in ACTH-treated cows (p < 0.05). Finally, immunohistochemistry performed in the dominant follicles of ACTH-treated cows detected higher expression of CYP17A1 and CYP21A2 (p < 0.05). These results suggest that the bovine ovary is able to respond locally to ACTH as a consequence of stress altering the expression of relevant steroidogenic enzymes. The results also confirm that the complete GC biosynthesis pathway is present in bovine dominant follicle and therefore GCs could be produced locally.
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Affiliation(s)
- L Etchevers
- Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias Del Litoral (ICiVet-Litoral), Universidad Nacional Del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina
| | - E M Belotti
- Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias Del Litoral (ICiVet-Litoral), Universidad Nacional Del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional Del Litoral (UNL), Esperanza, Santa Fe, Argentina
| | - P U Díaz
- Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias Del Litoral (ICiVet-Litoral), Universidad Nacional Del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional Del Litoral (UNL), Esperanza, Santa Fe, Argentina
| | - F M Rodríguez
- Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias Del Litoral (ICiVet-Litoral), Universidad Nacional Del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional Del Litoral (UNL), Esperanza, Santa Fe, Argentina
| | - F Rey
- Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias Del Litoral (ICiVet-Litoral), Universidad Nacional Del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional Del Litoral (UNL), Esperanza, Santa Fe, Argentina
| | - N R Salvetti
- Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias Del Litoral (ICiVet-Litoral), Universidad Nacional Del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional Del Litoral (UNL), Esperanza, Santa Fe, Argentina
| | - H H Ortega
- Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias Del Litoral (ICiVet-Litoral), Universidad Nacional Del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional Del Litoral (UNL), Esperanza, Santa Fe, Argentina
| | - A N Amweg
- Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias Del Litoral (ICiVet-Litoral), Universidad Nacional Del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional Del Litoral (UNL), Esperanza, Santa Fe, Argentina.
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14
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Structures of active melanocortin-4 receptor-Gs-protein complexes with NDP-α-MSH and setmelanotide. Cell Res 2021; 31:1176-1189. [PMID: 34561620 PMCID: PMC8563958 DOI: 10.1038/s41422-021-00569-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 08/31/2021] [Indexed: 02/07/2023] Open
Abstract
The melanocortin-4 receptor (MC4R), a hypothalamic master regulator of energy homeostasis and appetite, is a class A G-protein-coupled receptor and a prime target for the pharmacological treatment of obesity. Here, we present cryo-electron microscopy structures of MC4R–Gs-protein complexes with two drugs recently approved by the FDA, the peptide agonists NDP-α-MSH and setmelanotide, with 2.9 Å and 2.6 Å resolution. Together with signaling data from structure-derived MC4R mutants, the complex structures reveal the agonist-induced origin of transmembrane helix (TM) 6-regulated receptor activation. The ligand-binding modes of NDP-α-MSH, a high-affinity linear variant of the endogenous agonist α-MSH, and setmelanotide, a cyclic anti-obesity drug with biased signaling toward Gq/11, underline the key role of TM3 in ligand-specific interactions and of calcium ion as a ligand-adaptable cofactor. The agonist-specific TM3 interplay subsequently impacts receptor–Gs-protein interfaces at intracellular loop 2, which also regulates the G-protein coupling profile of this promiscuous receptor. Finally, our structures reveal mechanistic details of MC4R activation/inhibition, and provide important insights into the regulation of the receptor signaling profile which will facilitate the development of tailored anti-obesity drugs.
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15
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Verdinez JA, Sebag JA. Role of N-Linked Glycosylation in PKR2 Trafficking and Signaling. Front Neurosci 2021; 15:730417. [PMID: 34483834 PMCID: PMC8414166 DOI: 10.3389/fnins.2021.730417] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 07/27/2021] [Indexed: 12/26/2022] Open
Abstract
Prokineticin receptors are GPCRs involved in several physiological processes including the regulation of energy homeostasis, nociception, and reproductive function. PKRs are inhibited by the endogenous accessory protein MRAP2 which prevents them from trafficking to the plasma membrane. Very little is known about the importance of post-translational modification of PKRs and their role in receptor trafficking and signaling. Here we identify 2 N-linked glycosylation sites within the N-terminal region of PKR2 and demonstrate that glycosylation of PKR2 at position 27 is important for its plasma membrane localization and signaling. Additionally, we show that glycosylation at position 7 results in a decrease in PKR2 signaling through Gαs without impairing Gαq/11 signaling.
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Affiliation(s)
- Jissele A Verdinez
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA, United States.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, United States.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
| | - Julien A Sebag
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA, United States.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, United States.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
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16
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Benko AL, Wright AD, Sunyer T, Kovacs WJ, Olsen NJ. Pituitary neuropeptides and B lymphocyte function. Scand J Immunol 2021; 94:e13041. [PMID: 33817820 DOI: 10.1111/sji.13041] [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: 07/01/2020] [Revised: 03/16/2021] [Accepted: 03/21/2021] [Indexed: 11/28/2022]
Abstract
This review discusses the accumulated evidence that pro-opiomelanocortin (POMC) gene products as well as other pituitary neuropeptides derived from related genes (Proenkephalin, PENK; Prodynorphin, PDYN, and Pronociceptin, PNOC) can exert direct effects on B lymphocytes to modulate their functions. We also review the available data on receptor systems that might be involved in the transmission of such hormonal signals to B cells.
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Affiliation(s)
- Ann L Benko
- Division of Rheumatology, College of Medicine, The Pennsylvania State University, Hershey, PA, USA
| | | | | | - William J Kovacs
- Division of Endocrinology, Diabetes, and Metabolism, College of Medicine, The Pennsylvania State University, Hershey, PA, USA
| | - Nancy J Olsen
- Division of Rheumatology, College of Medicine, The Pennsylvania State University, Hershey, PA, USA
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17
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MRAP2 Interaction with Melanocortin-4 Receptor in SnakeHead ( Channa argus). Biomolecules 2021; 11:biom11030481. [PMID: 33807040 PMCID: PMC8004712 DOI: 10.3390/biom11030481] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/11/2021] [Accepted: 03/19/2021] [Indexed: 02/06/2023] Open
Abstract
The melanocortin-4 receptor (MC4R) plays an important role in the regulation of food intake and energy expenditure. Melanocortin-2 receptor accessory protein 2 (MRAP2) modulates trafficking, ligand binding, and signaling of MC4R. The Northern snakehead (Channa argus) is an economically important freshwater fish native to East Asia. To explore potential interaction between snakehead MC4R and MRAP2, herein we cloned snakehead mc4r and mrap2. The snakehead mc4r consisted of a 984 bp open reading frame encoding a protein of 327 amino acids, while snakehead mrap2 contained a 693 bp open reading frame encoding a protein of 230 amino acids. Synteny analysis indicated that mc4r was highly conserved with similar gene arrangement, while mrap2 contained two isoforms in teleost with different gene orders. Snakehead mc4r was primarily expressed in the brain, whereas mrap2 was expressed in the brain and intestine. Snakehead mc4r and mrap2 expression was modulated by fasting and refeeding. Further pharmacological experiments showed that the cloned snakehead MC4R was functional, capable of binding to peptide agonists and increasing intracellular cAMP production in a dose-dependent manner. Snakehead MC4R exhibited high constitutive activity. MRAP2 significantly decreased basal and agonist-stimulated cAMP signaling. These findings suggest that snakehead MC4R might be involved in energy balance regulation by interacting with MRAP2. Further studies are needed to elucidate MC4R in regulating diverse physiological processes in snakehead.
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18
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Wang M, Zhai Y, Lu L, Zhang C, Li N, Xue S, Cheng D, Fu S, Liu Q, Zhang C. Elucidation of the dimeric interplay of dual MRAP2 proteins in the zebrafish. J Cell Physiol 2021; 236:6472-6480. [PMID: 33559170 DOI: 10.1002/jcp.30321] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 11/07/2022]
Abstract
The melanocortin receptor accessory protein 2 (MRAP2) plays an essential role in the regulation of metabolic homeostasis and deletion of which results in severe obesity syndrome in mice and human. Mammalian MRAP2 is recognized as an endogenous physiological mediator through the potentiation of the MC4R signaling in vivo. Two isoforms of MRAP2 are identified in zebrafish genome, zMRAP2a and zMRAP2b. However, the mechanism of assembling dual topology and the regulatory roles of each complex on the melanocortin cascades remains unclear. In this study, we showed the bidirectional homo- and hetero-dimeric topologies of two zebrafish MRAP2 isoforms on the plasma membrane. Orientation fixed chimeric proteins could affect the trafficking and pharmacological properties of zMC4R signaling. Reciprocal replacement of zMRAP2a and zMRAP2b proteins elucidated the major participation of the carboxyl terminal as the functional domain for modulating zMC4R signaling. Our findings revealed the complex and dynamic conformational regulation of dual zebrafish MRAP2 proteins in vitro.
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Affiliation(s)
- Meng Wang
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yue Zhai
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Liumei Lu
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Cong Zhang
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Na Li
- Yantai Derui Bio-Tech Co.,Ltd, Yantai, Shandong, China
| | - Song Xue
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Daofu Cheng
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Shaliu Fu
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Qi Liu
- Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Chao Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Institute of Precision Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Signaling and Disease Research, Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
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19
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Rosenbaum MI, Clemmensen LS, Bredt DS, Bettler B, Strømgaard K. Targeting receptor complexes: a new dimension in drug discovery. Nat Rev Drug Discov 2020; 19:884-901. [PMID: 33177699 DOI: 10.1038/s41573-020-0086-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2020] [Indexed: 12/11/2022]
Abstract
Targeting receptor proteins, such as ligand-gated ion channels and G protein-coupled receptors, has directly enabled the discovery of most drugs developed to modulate receptor signalling. However, as the search for novel and improved drugs continues, an innovative approach - targeting receptor complexes - is emerging. Receptor complexes are composed of core receptor proteins and receptor-associated proteins, which have profound effects on the overall receptor structure, function and localization. Hence, targeting key protein-protein interactions within receptor complexes provides an opportunity to develop more selective drugs with fewer side effects. In this Review, we discuss our current understanding of ligand-gated ion channel and G protein-coupled receptor complexes and discuss strategies for their pharmacological modulation. Although such strategies are still in preclinical development for most receptor complexes, they exemplify how receptor complexes can be drugged, and lay the groundwork for this nascent area of research.
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Affiliation(s)
- Mette Ishøy Rosenbaum
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Louise S Clemmensen
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - David S Bredt
- Neuroscience Discovery, Janssen Pharmaceutical Companies of Johnson & Johnson, San Diego, CA, USA
| | - Bernhard Bettler
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Kristian Strømgaard
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
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20
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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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21
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Yin TC, Bauchle CJ, Rouault AAJ, Stephens SB, Sebag JA. The Insulinostatic Effect of Ghrelin Requires MRAP2 Expression in δ Cells. iScience 2020; 23:101216. [PMID: 32535024 PMCID: PMC7300157 DOI: 10.1016/j.isci.2020.101216] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 04/07/2020] [Accepted: 05/26/2020] [Indexed: 02/01/2023] Open
Abstract
Ghrelin regulates both energy intake and glucose homeostasis. In the endocrine pancreas, ghrelin inhibits insulin release to prevent hypoglycemia during fasting. The mechanism through which this is accomplished is unclear, but recent studies suggest that ghrelin acts on δ cells to stimulate somatostatin release, which in turn inhibits insulin release from β cells. Recently, the Melanocortin Receptor Accessory Protein 2 (MRAP2) was identified as an essential partner of the ghrelin receptor (GHSR1a) in mediating the central orexigenic action of ghrelin. In this study we show that MRAP2 is expressed in islet δ cells and is required for ghrelin to elicit a calcium response in those cells. Additionally, we show that both global and δ cell targeted deletion of MRAP2 abrogates the insulinostatic effect of ghrelin. Together, these findings establish that ghrelin signaling within δ cells is essential for the inhibition of insulin release and identify MRAP2 as a regulator of insulin secretion. δ Cells are responsible for the action of ghrelin in the endocrine pancreas MRAP2 is expressed in multiple cell types in the endocrine pancreas including δ cells MRAP2 is required for GHSR1a signaling in δ cells Deletion of MRAP2 results in loss of ghrelin-mediated inhibition of insulin secretion
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Affiliation(s)
- Terry C Yin
- Department of Molecular Physiology and Biophysics, Fraternal Order of Eagle Diabetes Research Center, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Casey J Bauchle
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Fraternal Order of Eagle Diabetes Research Center, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Alix A J Rouault
- Department of Molecular Physiology and Biophysics, Fraternal Order of Eagle Diabetes Research Center, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Samuel B Stephens
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Fraternal Order of Eagle Diabetes Research Center, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Julien A Sebag
- Department of Molecular Physiology and Biophysics, Fraternal Order of Eagle Diabetes Research Center, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA.
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22
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Yang Y, Harmon CM. Molecular determinants of ACTH receptor for ligand selectivity. Mol Cell Endocrinol 2020; 503:110688. [PMID: 31866318 DOI: 10.1016/j.mce.2019.110688] [Citation(s) in RCA: 4] [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: 07/30/2019] [Revised: 12/03/2019] [Accepted: 12/16/2019] [Indexed: 01/04/2023]
Abstract
The adrenocorticotropic hormone (ACTH) receptor, known as the melanocortin-2 receptor (MC2R), plays a key role in regulating adrenocortical function. ACTH receptor is a subtype of the melanocortin receptor family which is a member of the G-protein coupled receptor (GPCR) superfamily. ACTH receptor has unique characteristics among MCRs. α-MSH, β-MSH, γ-MSH and ACTH are agonists for MCRs but only ACTH is the agonist for ACTH receptor. In addition, the melanocortin receptor accessory protein (MRAP) is required for ACTH receptor expression at cell surface and function. In this review, we summarized the information available on the relationship between ACTH and ACTH receptor and provide the latest understanding of the molecular basis of the ACTH receptor responsible for ligand selectivity and function.
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Affiliation(s)
- Yingkui Yang
- Department of Surgery, State University of New York at Buffalo, USA.
| | - Carroll M Harmon
- Department of Surgery, State University of New York at Buffalo, USA
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23
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Abizaid A, Hougland JL. Ghrelin Signaling: GOAT and GHS-R1a Take a LEAP in Complexity. Trends Endocrinol Metab 2020; 31:107-117. [PMID: 31636018 PMCID: PMC7299083 DOI: 10.1016/j.tem.2019.09.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/25/2019] [Accepted: 09/27/2019] [Indexed: 12/30/2022]
Abstract
Ghrelin and the growth hormone secretagogue receptor 1a (GHS-R1a) are important targets for disorders related to energy balance and metabolic regulation. Pharmacological control of ghrelin signaling is a promising avenue to address health issues involving appetite, weight gain, obesity, and related metabolic disorders, and may be an option for patients suffering from wasting conditions like cachexia. In this review, we summarize recent developments in the biochemistry of ghrelin and GHS-R1a signaling. These include unravelling the enzymatic transformations that generate active ghrelin and the discovery of multiple proteins that interact with ghrelin and GHS-R1a to regulate signaling. Furthermore, we propose that harnessing these processes will lead to highly selective treatments to address obesity, diabetes, and other metabolism-linked disorders.
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Affiliation(s)
- Alfonso Abizaid
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | - James L Hougland
- Department of Chemistry, Syracuse University, Syracuse, NY, USA.
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24
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Rouault AAJ, Rosselli-Murai LK, Hernandez CC, Gimenez LE, Tall GG, Sebag JA. The GPCR accessory protein MRAP2 regulates both biased signaling and constitutive activity of the ghrelin receptor GHSR1a. Sci Signal 2020; 13:13/613/eaax4569. [PMID: 31911434 DOI: 10.1126/scisignal.aax4569] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ghrelin is a hormone secreted by the stomach during fasting periods and acts through its receptor, the growth hormone secretagogue 1a (GHSR1a), to promote food intake and prevent hypoglycemia. As such, GHSR1a is an important regulator of energy and glucose homeostasis and a target for the treatment of obesity. Here, we showed that the accessory protein MRAP2 altered GHSR1a signaling by inhibiting its constitutive activity, as well as by enhancing its G protein-dependent signaling and blocking the recruitment and signaling of β-arrestin in response to ghrelin. In addition, the effects of MRAP2 on the Gαq and β-arrestin pathways were independent and involved distinct regions of MRAP2. These findings may have implications for the regulation of ghrelin function in vivo and the role of MRAP2 in energy homeostasis. They also show that accessory proteins can bias signaling downstream of GPCRs in response to their endogenous agonist.
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Affiliation(s)
- Alix A J Rouault
- Department of Molecular Physiology and Biophysics, Fraternal Order of Eagles Diabetes Research Center, Iowa Neuroscience Institute, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA
| | | | - Ciria C Hernandez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Luis E Gimenez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gregory G Tall
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Julien A Sebag
- Department of Molecular Physiology and Biophysics, Fraternal Order of Eagles Diabetes Research Center, Iowa Neuroscience Institute, Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242, USA.
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25
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Baron M, Maillet J, Huyvaert M, Dechaume A, Boutry R, Loiselle H, Durand E, Toussaint B, Vaillant E, Philippe J, Thomas J, Ghulam A, Franc S, Charpentier G, Borys JM, Lévy-Marchal C, Tauber M, Scharfmann R, Weill J, Aubert C, Kerr-Conte J, Pattou F, Roussel R, Balkau B, Marre M, Boissel M, Derhourhi M, Gaget S, Canouil M, Froguel P, Bonnefond A. Loss-of-function mutations in MRAP2 are pathogenic in hyperphagic obesity with hyperglycemia and hypertension. Nat Med 2019; 25:1733-1738. [PMID: 31700171 PMCID: PMC6858878 DOI: 10.1038/s41591-019-0622-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 09/25/2019] [Indexed: 12/31/2022]
Abstract
The G-protein-coupled receptor (GPCR) accessory protein MRAP2 is implicated in energy control in rodents, notably via melanocortin-4 receptor (MC4R)1. Although some MRAP2 mutations have been described in people with obesity1–3, their functional consequences on adiposity remain elusive. Using large-scale sequencing of MRAP2 in 9,418 people, we identified 23 rare heterozygous variants associated with increased obesity risk in both adults and children. Functional assessment of each variant shows that loss-of-function MRAP2 variants are pathogenic for monogenic hyperphagic obesity, with hyperglycemia and hypertension. This contrasts with other monogenic forms of obesity characterized by excessive hunger, including MC4R deficiency, that present with low blood pressure and normal glucose tolerance4. The pleiotropic metabolic effect of loss-of-function mutations in MRAP2 might be due to the failure of different MRAP2-regulated GPCRs in various tissues including pancreatic islets.
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Affiliation(s)
- Morgane Baron
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Julie Maillet
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Marlène Huyvaert
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Aurélie Dechaume
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Raphaël Boutry
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Hélène Loiselle
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Emmanuelle Durand
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Bénédicte Toussaint
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Emmanuel Vaillant
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Julien Philippe
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France.,Center for Human Disease Modeling, Duke University Medical Center, Durham, NC, USA
| | - Jérémy Thomas
- Laboratoire de Biochimie et Hormonologie, Centre de Biologie Pathologie, Centre Hospitalier Régional Universitaire, Lille, France
| | - Amjad Ghulam
- Laboratoire de Biochimie et Hormonologie, Centre de Biologie Pathologie, Centre Hospitalier Régional Universitaire, Lille, France
| | - Sylvia Franc
- CERITD (Centre d'Étude et de Recherche pour l'Intensification du Traitement du Diabète), Evry, France.,Department of Diabetes, Sud-Francilien Hospital, University Paris-Sud, Orsay, Corbeil-Essonnes, France
| | - Guillaume Charpentier
- CERITD (Centre d'Étude et de Recherche pour l'Intensification du Traitement du Diabète), Evry, France.,Department of Diabetes, Sud-Francilien Hospital, University Paris-Sud, Orsay, Corbeil-Essonnes, France
| | | | - Claire Lévy-Marchal
- Department of Clinical Epidemiology, Inserm CIE 05, Robert Debré Hospital, Paris, France
| | - Maïthé Tauber
- Endocrinology, Obesity, Bone Disease, Genetics and Medical Gynecology, Hôpital des Enfants, Inserm UMR 1043, Université Toulouse III-Paul Sabatier, Toulouse, France
| | - Raphaël Scharfmann
- Inserm U1016, Institut Cochin, Université Paris Descartes, Paris, France
| | - Jacques Weill
- Pediatric Endocrine Department, Lille Hospital, Lille, France
| | | | - Julie Kerr-Conte
- Inserm U1190, EGID, CHU Lille, University of Lille, Lille, France
| | - François Pattou
- Inserm U1190, EGID, CHU Lille, University of Lille, Lille, France
| | - Ronan Roussel
- Department of Diabetology, Endocrinology and Nutrition, Hôpital Bichat, DHU FIRE, Assistance Publique Hôpitaux de Paris, Paris, France.,Inserm U1138, Centre de Recherche des Cordeliers, Paris, France.,UFR de Médecine, University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Beverley Balkau
- Inserm U1018, Center for Research in Epidemiology and Population Health, Villejuif, France.,University Paris-Saclay, University Paris-Sud, Villejuif, France
| | - Michel Marre
- Inserm U1138, Centre de Recherche des Cordeliers, Paris, France.,CMC Ambroise Paré, Neuilly-sur-Seine, France
| | - Mathilde Boissel
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Mehdi Derhourhi
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Stefan Gaget
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Mickaël Canouil
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France
| | - Philippe Froguel
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France. .,Department of Metabolism, Section of Genomics of Common Disease, Imperial College London, London, UK.
| | - Amélie Bonnefond
- CNRS UMR 8199, European Genomic Institute for Diabetes, Institut Pasteur de Lille, University of Lille, Lille, France. .,Department of Metabolism, Section of Genomics of Common Disease, Imperial College London, London, UK.
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26
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Wolverton EA, Wong MKS, Davis PE, Hoglin B, Braasch I, Dores RM. Analyzing the signaling properties of gar (Lepisosteus oculatus) melanocortin receptors: Evaluating interactions with MRAP1 and MRAP2. Gen Comp Endocrinol 2019; 282:113215. [PMID: 31276671 PMCID: PMC7263024 DOI: 10.1016/j.ygcen.2019.113215] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 06/29/2019] [Accepted: 06/30/2019] [Indexed: 12/18/2022]
Abstract
RT-PCR analysis of gar pituitary and brain indicated that different combinations of gar melanocortin receptor mRNAs are present in the same tissues with mRNAs for gar mrap1 and gar mrap2. Against this background, an objective of this study was to determine whether the ligand sensitivity for either ACTH or α-MSH was affected when gar (g) melanocortin receptors (Mcrs) were co-expressed with either of the accessory proteins gMrap1 or gMrap2 in Chinese Hamster Ovary cells. The results indicated that gMc2r has an obligatory requirement for co-expression with gMrap1 in order for the receptor to be activated by hACTH(1-24). In addition, activation of gMc2r did not occur when the receptor was expressed alone or co-expressed with gMrap2. Furthermore, co-expression of gMc2r with gMrap1 followed by stimulation with NDP-MSH resulted in a low level of activation (only at 10-7 M and 10-6 M). However, gMc1r, gMc3r, gMc4r, and gMc5r responded to stimulation by NDP-MSH in a more robust manner. Co-expression of gMc1r, gMc3r, gMc4r, and gMc5r with gMRAP1 had no effect on sensitivity to stimulation by NDP-MSH or hACTH(1-24). Co-expression with gMRAP2 had no negative or positive effect on ligand sensitivity for gMc1r, gMc3r, and gMc5r, however this treatment did increase the activation of CHO cells transfected with gMc4r following stimulation with both hACTH(1-24) (p < 0.001), and NDP-MSH (p < 0.001). Co-expression of gMC5R with either gMRAP1 or gMRAP2 increased trafficking of gMC5R to the plasma membrane. These pharmacological observations are compared to the response of melanocortin receptors from other neopterygian fishes, cartilaginous fishes, and tetrapods to stimulation by ACTH(1-24) and forms of α-MSH.
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Affiliation(s)
| | | | - Perry E Davis
- Department of Biological Sciences, University of Denver, USA
| | - Brianne Hoglin
- Department of Biological Sciences, University of Denver, USA
| | - Ingo Braasch
- Integrative Biology, Michigan State University, USA
| | - Robert M Dores
- Department of Biological Sciences, University of Denver, USA.
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27
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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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28
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Mechanisms of signalling and biased agonism in G protein-coupled receptors. Nat Rev Mol Cell Biol 2018; 19:638-653. [DOI: 10.1038/s41580-018-0049-3] [Citation(s) in RCA: 323] [Impact Index Per Article: 53.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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29
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Liang J, Li L, Jin X, Xu B, Pi L, Liu S, Zhu W, Zhang C, Luan B, Gong L, Zhang C. Pharmacological effect of human melanocortin-2 receptor accessory protein 2 variants on hypothalamic melanocortin receptors. Endocrine 2018; 61:94-104. [PMID: 29704154 DOI: 10.1007/s12020-018-1596-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 04/09/2018] [Indexed: 10/17/2022]
Abstract
PURPOSE Melanocortin-3 receptor (MC3R), melanocortin-4 receptor (MC4R), and a recently identified melanocortin-2 receptor accessory protein 2 (MRAP2), are highly expressed in hypothalamus and coordinately regulate energy homeostasis, but the single cellular transcriptome of melanocortin system remains unknown. Several infrequent MRAP2 variants are reported from severe obese human patients but the mechanisms on how they affect melanocortin signaling are unclear. METHODS First, we performed in silico analysis of mouse hypothalamus RNA sequencing datasets at single-cell resolution from two independent studies. Next, we inspected the three-dimensional conformational alteration of three mutations on MRAP2 protein. Finally, the influence of MRAP2 variants on MC3R and MC4R signaling was analyzed in vitro. RESULTS (1) We confirmed the actual co-expression of Mrap2 with Mc3r and Mc4r, and demonstrated more broad distribution of Mrap2-positive neuronal populations than Mc3r or Mc4r in mouse hypothalamus. (2) Compared with wild-type MRAP2, MRAP2N88Y, and MRAP2R125C showed impaired α-MSH-induced MC4R or MC3R stimulation. (3) MRAP2N88Yexhibited enhanced interaction with MC4R protein and its own. CONCLUSIONS This is the first dedicated description of single-cell transcriptome signature of Mrap2, Mc3r, and Mc4r in the central nerve system and the first evidence describing the unique dimer formation, conformational change, and pharmacological effect of MRAP2 mutations on MC3R signaling.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Animals
- Carrier Proteins/pharmacology
- Computer Simulation
- Genetic Variation
- Humans
- Hypothalamus/drug effects
- Hypothalamus/metabolism
- Mice
- Mutation/genetics
- Neurons/metabolism
- Nucleic Acid Conformation
- Plasmids
- RNA/genetics
- Receptor, Melanocortin, Type 3/genetics
- Receptor, Melanocortin, Type 3/metabolism
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Receptors, Melanocortin/drug effects
- Signal Transduction/genetics
- alpha-MSH/pharmacology
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Affiliation(s)
- Jinye Liang
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Lei Li
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xuanxuan Jin
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Bingxin Xu
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Linyu Pi
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Shangyun Liu
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Wei Zhu
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Cong Zhang
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Bing Luan
- Department of Endocrinology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Lulu Gong
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China.
| | - Chao Zhang
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China.
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30
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Zhang X, Saarinen AM, Campbell LE, De Filippis EA, Liu J. Regulation of Lipolytic Response and Energy Balance by Melanocortin 2 Receptor Accessory Protein (MRAP) in Adipocytes. Diabetes 2018; 67:222-234. [PMID: 29217655 PMCID: PMC5780064 DOI: 10.2337/db17-0862] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 11/22/2017] [Indexed: 12/27/2022]
Abstract
Melanocortin 2 receptor accessory protein (MRAP) is highly expressed in adrenal gland and adipose tissue. In adrenal cells, MRAP is essential for adrenocorticotropic hormone (ACTH)-induced activation of the cAMP/protein kinase A (PKA) pathway by melanocortin 2 receptor (MC2R), leading to glucocorticoid production and secretion. Although ACTH was known to stimulate PKA-dependent lipolysis, the functional involvement of MRAP in adipocyte metabolism remains incompletely defined. Herein, we found that knockdown or overexpression of MRAP in 3T3-L1 adipocytes reduced or increased ACTH-induced lipolysis, respectively. Moreover, an unbiased proteomics screen and coimmunoprecipitation analysis identified Gαs as a novel interacting partner of MRAP. An MRAP mutant disabled in Gαs association failed to augment the activation of PKA and lipolytic response to ACTH. Furthermore, compared with wild-type mice, transgenic mice (aP2-MRAP) overexpressing MRAP fat specifically exhibited increased lipolytic response to ACTH. When fed a high-fat diet (HFD), the transgenic mice displayed a significant decrease in the gain of adiposity and body weight as well as an improvement in glucose and insulin tolerance. These phenotypes were accompanied by increased adipose expression of genes for mitochondrial fatty acid oxidation and thermogenesis, and overall energy expenditure. Collectively, our data strongly suggest that MRAP plays a critical role in the regulation of ACTH-induced adipose lipolysis and whole-body energy balance.
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Affiliation(s)
- Xiaodong Zhang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Scottsdale, AZ
- HEALth Program, Mayo Clinic, Scottsdale, AZ
| | | | | | - Elena A De Filippis
- HEALth Program, Mayo Clinic, Scottsdale, AZ
- Division of Endocrinology, Mayo Clinic, Scottsdale, AZ
| | - Jun Liu
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Scottsdale, AZ
- HEALth Program, Mayo Clinic, Scottsdale, AZ
- Division of Endocrinology, Mayo Clinic, Scottsdale, AZ
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Rouault AA, Lee AA, Sebag JA. Regions of MRAP2 required for the inhibition of orexin and prokineticin receptor signaling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:2322-2329. [DOI: 10.1016/j.bbamcr.2017.09.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 09/10/2017] [Accepted: 09/17/2017] [Indexed: 10/18/2022]
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Melanocortins, Melanocortin Receptors and Multiple Sclerosis. Brain Sci 2017; 7:brainsci7080104. [PMID: 28805746 PMCID: PMC5575624 DOI: 10.3390/brainsci7080104] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 08/07/2017] [Accepted: 08/08/2017] [Indexed: 02/07/2023] Open
Abstract
The melanocortins and their receptors have been extensively investigated for their roles in the hypothalamo-pituitary-adrenal axis, but to a lesser extent in immune cells and in the nervous system outside the hypothalamic axis. This review discusses corticosteroid dependent and independent effects of melanocortins on the peripheral immune system, central nervous system (CNS) effects mediated through neuronal regulation of immune system function, and direct effects on endogenous cells in the CNS. We have focused on the expression and function of melanocortin receptors in oligodendroglia (OL), the myelin producing cells of the CNS, with the goal of identifying new therapeutic approaches to decrease CNS damage in multiple sclerosis as well as to promote repair. It is clear that melanocortin signaling through their receptors in the CNS has potential for neuroprotection and repair in diseases like MS. Effects of melanocortins on the immune system by direct effects on the circulating cells (lymphocytes and monocytes) and by signaling through CNS cells in regions lacking a mature blood brain barrier are clear. However, additional studies are needed to develop highly effective MCR targeted therapies that directly affect endogenous cells of the CNS, particularly OL, their progenitors and neurons.
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