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Ringuet MT, Furness JB, Furness SGB. G protein-coupled receptor interactions and modification of signalling involving the ghrelin receptor, GHSR1a. J Neuroendocrinol 2022; 34:e13077. [PMID: 34931385 DOI: 10.1111/jne.13077] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/05/2021] [Indexed: 12/28/2022]
Abstract
The growth hormone secretagogue receptor 1a (GHSR1a) is intriguing because of its potential as a therapeutic target and its diverse molecular interactions. Initial studies of the receptor focused on the potential therapeutic ability for growth hormone (GH) release to reduce wasting in aging individuals, as well as food intake regulation for treatment of cachexia. Known roles of GHSR1a now extend to regulation of neurogenesis, learning and memory, gastrointestinal motility, glucose/lipid metabolism, the cardiovascular system, neuronal protection, motivational salience, and hedonic feeding. Ghrelin, the endogenous agonist of GHSR1a, is primarily located in the stomach and is absent from the central nervous system (CNS), including the spinal cord. However, ghrelin in the circulation does have access to a small number of CNS sites, including the arcuate nucleus, which is important in feeding control. At some sites, such as at somatotrophs, GHSR1a has high constitutive activity. Typically, ghrelin-dependent and constitutive GHSR1a activation occurs via Gαq/11 pathways. In vitro and in vivo data suggest that GHSR1a heterodimerises with multiple G protein-coupled receptors (GPCRs), including dopamine D1 and D2, serotonin 2C, orexin, oxytocin and melanocortin 3 receptors (MCR3), as well as the MCR3 accessory protein, MRAP2, providing possible mechanisms for its many physiological effects. In all cases, the receptor interaction changes downstream signalling and the responses to receptor agonists. This review discusses the signalling mechanisms of GHSR1a alone and in combination with other GPCRs, and explores the physiological consequences of GHSR1a coupling with other GPCRs.
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Affiliation(s)
- Mitchell Ty Ringuet
- Department of Anatomy and Physiology, University of Melbourne, Parkville, VIC, Australia
| | - John Barton Furness
- Department of Anatomy and Physiology, University of Melbourne, Parkville, VIC, Australia
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
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2
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Bukhari SNA. An insight into the multifunctional role of ghrelin and structure activity relationship studies of ghrelin receptor ligands with clinical trials. Eur J Med Chem 2022; 235:114308. [PMID: 35344905 DOI: 10.1016/j.ejmech.2022.114308] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 02/06/2022] [Accepted: 03/18/2022] [Indexed: 11/30/2022]
Abstract
Ghrelin is a multifunctional gastrointestinal acylated peptide, primarily synthesized in the stomach and regulates the secretion of growth hormone and energy homeostasis. It plays a central role in modulating the diverse biological, physiological and pathological functions in vertebrates. The synthesis of ghrelin receptor ligands after the finding of growth hormone secretagogue developed from Met-enkephalin led to reveal the endogenous ligand ghrelin and the receptors. Subsequently, many peptides, small molecules and peptidomimetics focusing on the ghrelin receptor, GHS-R1a, were derived. In this review, the key features of ghrelin's structure, forms, its bio-physiological functions, pathological roles and therapeutic potential have been highlighted. A few peptidomimetics and pseudo peptide synthetic perspectives have also been discussed to make ghrelin receptor ligands, clinical trials and their success.
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Affiliation(s)
- Syed Nasir Abbas Bukhari
- Department of Pharmaceutical Chemistry, College of Pharmacy, Jouf University, Sakaka, Aljouf, 2014, Saudi Arabia.
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3
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Molecular recognition of an acyl-peptide hormone and activation of ghrelin receptor. Nat Commun 2021; 12:5064. [PMID: 34417468 PMCID: PMC8379176 DOI: 10.1038/s41467-021-25364-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 08/06/2021] [Indexed: 02/07/2023] Open
Abstract
Ghrelin, also called “the hunger hormone”, is a gastric peptide hormone that regulates food intake, body weight, as well as taste sensation, reward, cognition, learning and memory. One unique feature of ghrelin is its acylation, primarily with an octanoic acid, which is essential for its binding and activation of the ghrelin receptor, a G protein-coupled receptor. The multifaceted roles of ghrelin make ghrelin receptor a highly attractive drug target for growth retardation, obesity, and metabolic disorders. Here we present two cryo-electron microscopy structures of Gq-coupled ghrelin receptor bound to ghrelin and a synthetic agonist, GHRP-6. Analysis of these two structures reveals a unique binding pocket for the octanoyl group, which guides the correct positioning of the peptide to initiate the receptor activation. Together with mutational and functional data, our structures define the rules for recognition of the acylated peptide hormone and activation of ghrelin receptor, and provide structural templates to facilitate drug design targeting ghrelin receptor. Ghrelin is a gastric peptide hormone and its acylation is required for binding to and activation of the ghrelin receptor in the brain, which initiates appetite. Here, the authors present cryo-EM structures of the Gq-coupled ghrelin receptor bound to ghrelin and the synthetic agonist GHRP-6 and they describe how the acylated peptide hormone is recognised by the receptor, which is of interest for drug design.
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4
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Stoyanova I, Lutz D. Ghrelin-Mediated Regeneration and Plasticity After Nervous System Injury. Front Cell Dev Biol 2021; 9:595914. [PMID: 33869167 PMCID: PMC8046019 DOI: 10.3389/fcell.2021.595914] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 02/24/2021] [Indexed: 12/17/2022] Open
Abstract
The nervous system is highly vulnerable to different factors which may cause injury followed by an acute or chronic neurodegeneration. Injury involves a loss of extracellular matrix integrity, neuronal circuitry disintegration, and impairment of synaptic activity and plasticity. Application of pleiotropic molecules initiating extracellular matrix reorganization and stimulating neuronal plasticity could prevent propagation of the degeneration into the tissue surrounding the injury. To find an omnipotent therapeutic molecule, however, seems to be a fairly ambitious task, given the complex demands of the regenerating nervous system that need to be fulfilled. Among the vast number of candidates examined so far, the neuropeptide and hormone ghrelin holds within a very promising therapeutic potential with its ability to cross the blood-brain barrier, to balance metabolic processes, and to stimulate neurorepair and neuroactivity. Compared with its well-established systemic effects in treatment of metabolism-related disorders, the therapeutic potential of ghrelin on neuroregeneration upon injury has received lesser appreciation though. Here, we discuss emerging concepts of ghrelin as an omnipotent player unleashing developmentally related molecular cues and morphogenic cascades, which could attenuate and/or counteract acute and chronic neurodegeneration.
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Affiliation(s)
- Irina Stoyanova
- Department of Anatomy and Cell Biology, Medical University Varna, Varna, Bulgaria
| | - David Lutz
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany
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5
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Abstract
G protein-coupled receptors (GPCRs) represent the largest family of approved therapeutic targets. Ligands stimulating these receptors specifically activate multiple signalling pathways that induce not only the desired therapeutic response, but sometimes untolerated side effects that limit their clinical use. The diversity in signalling induced by each ligand could be considered a viable path for improving this situation. Biased agonism, which offers the promise of identifying pathway-selective drugs has been proposed as a means to exploit this opportunity. However, identifying biased agonists is not an easy process and quantifying ligand bias for a given signalling pathway requires careful consideration and control of several confounding factors. To date, the molecular mechanisms of biased signalling remain unclear and known theories that constitute our understanding of the mechanisms underlying therapeutic and side effects are still being challenged, making the strategy of selecting promising potential drugs more difficult. This special issue summarizes the latest advances in the discovery and optimization of biased ligands for different GPCRs. It also focuses on identifying novel insights into the field of biased agonism, while at the same time, highlighting the conceptual and experimental limitations of that concept for drug discovery. This aims to broaden our understanding of the signalling induced by the various identified biased agonists and provide perspectives that could straighten our path towards the development of more effective and tolerable therapeutics.
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Affiliation(s)
- Karim Nagi
- College of Medicine, QU Health, Qatar University, Doha, Qatar; Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha, Qatar.
| | - H Ongun Onaran
- Ankara University, Faculty of Medicine, Department of Pharmacology, Molecular Biology and Technology Development Unit, Ankara, Turkey
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6
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Biased signaling: A viable strategy to drug ghrelin receptors for the treatment of obesity. Cell Signal 2021; 83:109976. [PMID: 33713808 DOI: 10.1016/j.cellsig.2021.109976] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/23/2021] [Accepted: 03/08/2021] [Indexed: 02/07/2023]
Abstract
Obesity is a global burden and a chronic ailment with damaging overall health effects. Ghrelin, an octanoylated 28 amino acid peptide hormone, is secreted from the oxyntic mucosa of the stomach. Ghrelin acts on regions of the hypothalamus to regulate feeding behavior and glucose homeostasis through its G protein-coupled receptor. Recently, several central pathways modulating the metabolic actions of ghrelin have been reported. While these signaling pathways can be inhibited or activated by antagonists or agonists, they can also be discriminatingly activated in a "biased" response to impart different degrees of activation in distinct pathways downstream of the receptor. Here, we review recent ghrelin biased signaling findings as well as characteristics of ghrelin hormone and its receptors pertinent for biased signaling. We then evaluate the feasibility for ghrelin receptor biased signaling as a strategy for the development of effective pharmacotherapy in obesity treatment.
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7
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de la Nuez Veulens A, Rodríguez Fernández RE, Álvarez Ginarte YM, Montero Cabrera LA. In silico strategy for detailing the binding modes of a novel family of peptides proven as ghrelin receptor agonists. J Mol Model 2020; 26:294. [PMID: 33015729 DOI: 10.1007/s00894-020-04553-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 09/17/2020] [Indexed: 11/26/2022]
Abstract
Ghrelin is a peptide hormone involved in multiple functions, including growth hormone release stimulation, food intake regulation, and metabolic and cytoprotective effect. A novel family of peptides with internal cycles was designed as ghrelin analogs and the biological activity of two of them (A228 and A233) was experimentally studied in-depth. In this work, an in silico strategy was developed for describing and assessing the binding modes of A228 and A233 to GHS-R1a (ghrelin receptor) comparing it with ghrelin and GHRP-6 peptides. Several reported structures of different G protein coupled receptors were used as templates, to obtain a good quality model of GHS-R1a. The best model was selected by preliminary molecular docking with ghrelin and GHRP-6. Docking was used to estimate peptide orientations in the binding site of the best model, observing a superposition of its N-terminal and its first aromatic residue. To test the complex stability in time, the C-terminal fragments of each peptide were added and the complexes were inserted a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membrane, performing a molecular dynamic simulation for 100 ns using the CHARMM36 force field. Despite of the structural differences, the studied peptides share a common binding mode; the N-terminal interacts with E124 and the aromatic residue close to it, with the aromatic cluster (F279, F309, and F312). A preliminary pharmacophore model, consisting in a positive charged amine and an aromatic ring at an approximate distance of 0.79 nm, can be proposed. The results here described could represent a step forward in the efficient search of new ghrelin analogs.
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Affiliation(s)
| | | | - Yoanna M Álvarez Ginarte
- Laboratory of Theoretical and Computational Chemistry, Faculty of Chemistry, University of Havana, Havana, Cuba
| | - Luis A Montero Cabrera
- Laboratory of Theoretical and Computational Chemistry, Faculty of Chemistry, University of Havana, Havana, Cuba.
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, USA.
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8
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Nicke L, Horx P, Müller R, Els-Heindl S, Geyer A. Tryptophan Analogues with Fixed Side-Chain Orientation: Expanding the Scope. Chembiochem 2020; 22:330-335. [PMID: 33463878 PMCID: PMC7891422 DOI: 10.1002/cbic.202000424] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/12/2020] [Indexed: 12/13/2022]
Abstract
A generalized synthetic strategy is proposed here for the synthesis of asymmetric β‐indoylated amino acids by 8‐aminoquinoline (8AQ)‐directed C(sp3)‐H functionalization of suitably protected precursors. Peptides containing one of the four stereoisomers of (indol‐3‐yl)‐3‐phenylalanine at position 2 of the parent peptide KwFwLL‐NH2 (w=d‐Trp) cover a wide range of activities as ghrelin receptor inverse agonists, among them the most active described until now. This application exemplarily shows how β‐indoylated amino acids can be used for the systematic variation of the position of an indole group in a bioactive peptide.
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Affiliation(s)
- Lennart Nicke
- Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein-Strasse 4, 35032, Marburg, Germany
| | - Philip Horx
- Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein-Strasse 4, 35032, Marburg, Germany
| | - Ronny Müller
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
| | - Sylvia Els-Heindl
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
| | - Armin Geyer
- Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein-Strasse 4, 35032, Marburg, Germany
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9
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Cooper M, Llinas A, Hansen P, Caffrey M, Ray A, Sjödin S, Shamovsky I, Wada H, Jellesmark Jensen T, Sivars U, Hultin L, Andersson U, Lundqvist S, Gedda K, Jinton L, Krutrök N, Lewis R, Jansson P, Gardelli C. Identification and Optimization of Pyrrolidine Derivatives as Highly Potent Ghrelin Receptor Full Agonists. J Med Chem 2020; 63:9705-9730. [PMID: 32787075 DOI: 10.1021/acs.jmedchem.0c00828] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Muscle atrophy and cachexia are common comorbidities among patients suffering from cancer, chronic obstructive pulmonary disease, and several other chronic diseases. The peptide hormone ghrelin exerts pleiotropic effects including the stimulation of growth hormone secretion and subsequent increase of insulin-like growth factor-1 levels, an important mediator of muscle growth and repair. Ghrelin also acts on inflammation, appetite, and adipogenesis and therefore has been considered a promising therapeutic target for catabolic conditions. We previously reported on the synthesis and properties of an indane based series of ghrelin receptor full agonists which led to a sustained increase of insulin-like growth factor-1 in a dog pharmacodynamic study. Herein we report on the identification of a series of pyrrolidine or piperidine based full agonists and attempted optimization to give compounds with profiles suitable for progression as clinical candidates.
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Affiliation(s)
| | | | | | | | | | - Stina Sjödin
- Pharmaceutical Sciences, BioPharmaceuticals R&D, AstraZeneca, Mölndal SE-43183, Sweden
| | | | | | - Tina Jellesmark Jensen
- Early Clinical Development, Research and Early Development, Respiratory, Inflammation and Autoimmune (RIA), BioPharmaceuticals R&D, AstraZeneca, Mölndal SE-43183, Sweden
| | | | - Leif Hultin
- In Vivo Imaging Sciences, Clinical Pharmacology & Safety Sciences, R&D, AstraZeneca, Mölndal SE-43183, Sweden
| | - Ulf Andersson
- Clinical Pharmacology & Safety Sciences, R&D, AstraZeneca, Mölndal SE-43183, Sweden
| | - Sara Lundqvist
- Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Mölndal SE-43183, Sweden
| | - Karin Gedda
- Precision Medicine, Oncology R&D, AstraZeneca, Mölndal SE-43183, Sweden
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10
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Worm DJ, Els‐Heindl S, Beck‐Sickinger AG. Targeting of peptide‐binding receptors on cancer cells with peptide‐drug conjugates. Pept Sci (Hoboken) 2020. [DOI: 10.1002/pep2.24171] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Dennis J. Worm
- Faculty of Life Sciences, Institute of BiochemistryLeipzig University Leipzig Germany
| | - Sylvia Els‐Heindl
- Faculty of Life Sciences, Institute of BiochemistryLeipzig University Leipzig Germany
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11
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Hedegaard MA, Holst B. The Complex Signaling Pathways of the Ghrelin Receptor. Endocrinology 2020; 161:5734640. [PMID: 32049280 DOI: 10.1210/endocr/bqaa020] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/10/2020] [Indexed: 12/13/2022]
Abstract
The ghrelin receptor (GhrR) is known for its strong orexigenic effects in pharmacological doses and has long been considered as a promising target for the treatment of obesity. Several antagonists have been developed to decrease the orexigenic signaling, but none of these have been approved for the treatment of obesity because of adverse effects and lack of efficacy. Heterodimerization and biased signaling are important concepts for G-protein coupled receptor (GPCR) signaling, and the influence of these aspects on the GhrR may be important for feeding behavior and obesity. GhrR has been described to heterodimerize with other GPCRs, such as the dopamine receptors 1 and 2, leading to a modulation of the signaling properties of both dimerization partners. Another complicating factor of GhrR-mediated signaling is its ability to activate several different signaling pathways on ligand stimulation. Importantly, some ligands have shown to be "biased" or "functionally selective," implying that the ligand favors a particular signaling pathway. These unique signaling properties could have a sizeable impact on the physiological functions of the GhrR system. Importantly, heterodimerization may explain why the GhrR is expressed in areas of the brain that are difficult for peptide ligands to access. One possibility is that the purpose of GhrR expression is to modulate the function of other receptors in addition to merely being independently activated. We suggest that a deeper understanding of the signaling properties of the GhrR will facilitate future drug discovery in the areas of obesity and weight management.
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Affiliation(s)
- Morten Adler Hedegaard
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Birgitte Holst
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
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12
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Nicke L, Müller R, Geyer A, Els-Heindl S. Side Chain Orientation of Tryptophan Analogues Determines Agonism and Inverse Agonism in Short Ghrelin Peptides. ChemMedChem 2019; 14:1849-1855. [PMID: 31442005 PMCID: PMC6899459 DOI: 10.1002/cmdc.201900409] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/23/2019] [Indexed: 02/06/2023]
Abstract
We describe two synthetic amino acids with inverted side chain stereochemistry, which induce opposite biological activity. Phe4 is an important part of the activation motif of ghrelin, and in short peptide inverse agonists such as KwFwLL-NH2 , the aromatic core is necessary for inactivation of the receptor. To restrict indole/phenyl mobility and simultaneously strengthen the interaction between peptide and receptor, we exchanged the natural monoaryl amino acids for diaryl amino acids derived from tryptophan. By standard solid-phase peptide synthesis, each of them was inserted into ghrelin or in the aromatic core of the inverse agonist. Both ghrelin analogues showed nanomolar activity, indicating sufficient space to accommodate the additional side chain. In contrast, diaryl amino acids in the inverse agonist had considerable influence on receptor signaling. Whereas the introduction of Wsf maintains inverse agonism of the peptide, Wrf shifts the receptor more to active states and can induce agonism depending on its introduction site.
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Affiliation(s)
- Lennart Nicke
- Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein-Strasse 4, 35032, Marburg, Germany
| | - Ronny Müller
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
| | - Armin Geyer
- Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein-Strasse 4, 35032, Marburg, Germany
| | - Sylvia Els-Heindl
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstrasse 34, 04103, Leipzig, Germany
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13
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Abstract
PURPOSE OF REVIEW Obesity is affecting over 600 million adults worldwide and has numerous negative effects on health. Since ghrelin positively regulates food intake and body weight, targeting its signaling to induce weight loss under conditions of obesity seems promising. Thus, the present work reviews and discusses different possibilities to alter ghrelin signaling. RECENT FINDINGS Ghrelin signaling can be altered by RNA Spiegelmers, GHSR/Fc, ghrelin-O-acyltransferase inhibitors as well as antagonists, and inverse agonists of the ghrelin receptor. PF-05190457 is the first inverse agonist of the ghrelin receptor tested in humans shown to inhibit growth hormone secretion, gastric emptying, and reduce postprandial glucose levels. Effects on body weight were not examined. Although various highly promising agents targeting ghrelin signaling exist, so far, they were mostly only tested in vitro or in animal models. Further research in humans is thus needed to further assess the effects of ghrelin antagonism on body weight especially under conditions of obesity.
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Affiliation(s)
- Martha A Schalla
- Charité Center for Internal Medicine and Dermatology, Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine; Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Andreas Stengel
- Charité Center for Internal Medicine and Dermatology, Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine; Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
- Department of Psychosomatic Medicine and Psychotherapy, Medical University Hospital Tübingen, Tübingen, Germany.
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14
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Bender BJ, Vortmeier G, Ernicke S, Bosse M, Kaiser A, Els-Heindl S, Krug U, Beck-Sickinger A, Meiler J, Huster D. Structural Model of Ghrelin Bound to its G Protein-Coupled Receptor. Structure 2019; 27:537-544.e4. [PMID: 30686667 DOI: 10.1016/j.str.2018.12.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/14/2018] [Accepted: 12/05/2018] [Indexed: 12/27/2022]
Abstract
The peptide ghrelin targets the growth hormone secretagogue receptor 1a (GHSR) to signal changes in cell metabolism and is a sought-after therapeutic target, although no structure is known to date. To investigate the structural basis of ghrelin binding to GHSR, we used solid-state nuclear magnetic resonance (NMR) spectroscopy, site-directed mutagenesis, and Rosetta modeling. The use of saturation transfer difference NMR identified key residues in the peptide for receptor binding beyond the known motif. This information combined with assignment of the secondary structure of ghrelin in its receptor-bound state was incorporated into Rosetta using an approach that accounts for flexible binding partners. The NMR data and models revealed an extended binding surface that was confirmed via mutagenesis. Our results agree with a growing evidence of peptides interacting via two sites at G protein-coupled receptors.
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Affiliation(s)
- Brian Joseph Bender
- Department of Pharmacology and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Gerrit Vortmeier
- Institute for Medical Physics and Biophysics, Medical Department, Leipzig University, Härtelstrasse 16-18, 04107 Leipzig, Germany
| | - Stefan Ernicke
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstrasse 34, 04103 Leipzig, Germany
| | - Mathias Bosse
- Institute for Medical Physics and Biophysics, Medical Department, Leipzig University, Härtelstrasse 16-18, 04107 Leipzig, Germany
| | - Anette Kaiser
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstrasse 34, 04103 Leipzig, Germany
| | - Sylvia Els-Heindl
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstrasse 34, 04103 Leipzig, Germany
| | - Ulrike Krug
- Institute for Medical Physics and Biophysics, Medical Department, Leipzig University, Härtelstrasse 16-18, 04107 Leipzig, Germany
| | - Annette Beck-Sickinger
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstrasse 34, 04103 Leipzig, Germany
| | - Jens Meiler
- Department of Pharmacology and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA.
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, Medical Department, Leipzig University, Härtelstrasse 16-18, 04107 Leipzig, Germany.
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15
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Martínez Damonte V, Rodríguez SS, Raingo J. Growth hormone secretagogue receptor constitutive activity impairs voltage-gated calcium channel-dependent inhibitory neurotransmission in hippocampal neurons. J Physiol 2018; 596:5415-5428. [PMID: 30199095 DOI: 10.1113/jp276256] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 09/06/2018] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Presynaptic CaV 2 voltage-gated calcium channels link action potentials arriving at the presynaptic terminal to neurotransmitter release. Hence, their regulation is essential to fine tune brain circuitry. CaV 2 channels are highly sensitive to G protein-coupled receptor (GPCR) modulation. Our previous data indicated that growth hormone secretagogue receptor (GHSR) constitutive activity impairs CaV 2 channels by decreasing their surface density. We present compelling support for the impact of CaV 2.2 channel inhibition by agonist-independent GHSR activity exclusively on GABA release in hippocampal cultures. We found that this selectivity arises from a high reliance of GABA release on CaV 2.2 rather than on CaV 2.1 channels. Our data provide new information on the effects of the ghrelin-GHSR system on synaptic transmission, suggesting a putative physiological role of the constitutive signalling of a GPCR that is expressed at high levels in brain areas with restricted access to its natural agonist. ABSTRACT Growth hormone secretagogue receptor (GHSR) displays high constitutive activity, independent of its endogenous ligand, ghrelin. Unlike ghrelin-induced GHSR activity, the physiological role of GHSR constitutive activity and the mechanisms that underlie GHSR neuronal modulation remain elusive. We previously demonstrated that GHSR constitutive activity modulates presynaptic CaV 2 voltage-gated calcium channels. Here we postulate that GHSR constitutive activity-mediated modulation of CaV 2 channels could be relevant in the hippocampus since this brain area has high GHSR expression but restricted access to ghrelin. We performed whole-cell patch-clamp in hippocampal primary cultures from E16- to E18-day-old C57BL6 wild-type and GHSR-deficient mice after manipulating GHSR expression with lentiviral transduction. We found that GHSR constitutive activity impairs CaV 2.1 and CaV 2.2 native calcium currents and that CaV 2.2 basal impairment leads to a decrease in GABA but not glutamate release. We postulated that this selective effect is related to a higher CaV 2.2 over CaV 2.1 contribution to GABA release (∼40% for CaV 2.2 in wild-type vs. ∼20% in wild-type GHSR-overexpressing cultures). This effect of GHSR constitutive activity is conserved in hippocampal brain slices, where GHSR constitutive activity reduces local GABAergic transmission of the granule cell layer (intra-granule cell inhibitory postsynaptic current (IPSC) size ∼-67 pA in wild-type vs. ∼-100 pA in GHSR-deficient mice), whereas the glutamatergic output from the dentate gyrus to CA3 remains unchanged. In summary, we found that GHSR constitutive activity impairs IPSCs both in hippocampal primary cultures and in brain slices through a CaV 2-dependent mechanism without affecting glutamatergic transmission.
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Affiliation(s)
- Valentina Martínez Damonte
- Multidisciplinary Institute of Cell Biology (IMBICE), National Council of Science and Technology (CONICET), Buenos Aires Comision of Science (CIC) and La Plata University (UNLP), La Plata, Argentina
| | - Silvia Susana Rodríguez
- Multidisciplinary Institute of Cell Biology (IMBICE), National Council of Science and Technology (CONICET), Buenos Aires Comision of Science (CIC) and La Plata University (UNLP), La Plata, Argentina
| | - Jesica Raingo
- Multidisciplinary Institute of Cell Biology (IMBICE), National Council of Science and Technology (CONICET), Buenos Aires Comision of Science (CIC) and La Plata University (UNLP), La Plata, Argentina
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16
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Daina A, Giuliano C, Pietra C, Wang J, Chi Y, Zou Z, Li F, Yan Z, Zhou Y, Guainazzi A, Garcia Rubio S, Zoete V. Rational Design, Synthesis, and Pharmacological Characterization of Novel Ghrelin Receptor Inverse Agonists as Potential Treatment against Obesity-Related Metabolic Diseases. J Med Chem 2018; 61:11039-11060. [DOI: 10.1021/acs.jmedchem.8b00794] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Antoine Daina
- Molecular Modeling Group, SIB Swiss Institute of Bioinformatics, CH-1015 Lausanne, Switzerland
| | - Claudio Giuliano
- Research and Preclinical Development Department, Helsinn Healthcare, CH-6912 Lugano, Switzerland
| | - Claudio Pietra
- Research and Preclinical Development Department, Helsinn Healthcare, CH-6912 Lugano, Switzerland
| | - Junbo Wang
- Department of Medicinal Chemistry, Pharmacokinetics and Metabolism, Sundia MediTech, 388 Jialilue Road, Zhangjiang Hi-Tech Park, Shanghai 201203, China
| | - Yushi Chi
- Department of Medicinal Chemistry, Pharmacokinetics and Metabolism, Sundia MediTech, 388 Jialilue Road, Zhangjiang Hi-Tech Park, Shanghai 201203, China
| | - Zack Zou
- Department of Medicinal Chemistry, Pharmacokinetics and Metabolism, Sundia MediTech, 388 Jialilue Road, Zhangjiang Hi-Tech Park, Shanghai 201203, China
| | - Fugang Li
- Department of Discovery Biology, HD Biosciences, 590 Ruiqing Road Zhangjiang East Campus, Shanghai 201201, China
| | - Zhonghua Yan
- Department of Discovery Biology, HD Biosciences, 590 Ruiqing Road Zhangjiang East Campus, Shanghai 201201, China
| | - Yifan Zhou
- Department of Discovery Biology, HD Biosciences, 590 Ruiqing Road Zhangjiang East Campus, Shanghai 201201, China
| | - Angelo Guainazzi
- Research and Development Department, Helsinn Therapeutics (US), Inc., Iselin, New Jersey 08830, United-States
| | - Silvina Garcia Rubio
- Research and Development Department, Helsinn Therapeutics (US), Inc., Iselin, New Jersey 08830, United-States
| | - Vincent Zoete
- Molecular Modeling Group, SIB Swiss Institute of Bioinformatics, CH-1015 Lausanne, Switzerland
- Department of Fundamental Oncology, Lausanne University, Ludwig Institute for Cancer Research, Route de la Corniche 9A, 1066 Epalinges, Switzerland
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17
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Worm DJ, Els-Heindl S, Kellert M, Kuhnert R, Saretz S, Koebberling J, Riedl B, Hey-Hawkins E, Beck-Sickinger AG. A stable meta-carborane enables the generation of boron-rich peptide agonists targeting the ghrelin receptor. J Pept Sci 2018; 24:e3119. [PMID: 30168238 DOI: 10.1002/psc.3119] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 12/26/2022]
Abstract
Boron neutron capture therapy (BNCT) is a binary cancer therapy, which combines the biochemical targeting of a boron-containing drug with the regional localization of radiation treatment. Although the concept of BNCT has been known for decades, the selective delivery of boron into tumor cells remains challenging. G protein-coupled receptors that are overexpressed on cancer cells in combination with peptidic ligands can be potentially used as shuttle system for a tumor-directed boron uptake. In this study, we present the generation of short, boron-rich peptide conjugates that target the ghrelin receptor. Expression of the ghrelin receptor on various cancer cells makes it a viable target for BNCT. We designed a novel hexapeptide super-agonist that was modified with different specifically synthesized carborane monoclusters and tested for ghrelin receptor activation. A meta-carborane building block with a mercaptoacetic acid linker was found to be optimal for peptide modification, owing to its chemical stability and a suitable activation efficacy of the conjugate. The versatility of this carborane for the development of peptidic boron delivery agents was further demonstrated by the generation of highly potent, boron-loaded conjugates using the backbone of the known ghrelin receptor ligands growth hormone releasing peptide 6 and Ipamorelin.
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Affiliation(s)
- Dennis J Worm
- Faculty of Life Sciences, Institute of Biochemistry, Universität Leipzig, Brüderstrasse 34, 04103, Leipzig, Germany
| | - Sylvia Els-Heindl
- Faculty of Life Sciences, Institute of Biochemistry, Universität Leipzig, Brüderstrasse 34, 04103, Leipzig, Germany
| | - Martin Kellert
- Faculty of Chemistry and Mineralogy, Institute of Inorganic Chemistry, Universität Leipzig, Johannisallee 29, 04103, Leipzig, Germany
| | - Robert Kuhnert
- Faculty of Chemistry and Mineralogy, Institute of Inorganic Chemistry, Universität Leipzig, Johannisallee 29, 04103, Leipzig, Germany
| | - Stefan Saretz
- Faculty of Chemistry and Mineralogy, Institute of Inorganic Chemistry, Universität Leipzig, Johannisallee 29, 04103, Leipzig, Germany
| | | | - Bernd Riedl
- Bayer AG, Aprather Weg 18A, 42113, Wuppertal, Germany
| | - Evamarie Hey-Hawkins
- Faculty of Chemistry and Mineralogy, Institute of Inorganic Chemistry, Universität Leipzig, Johannisallee 29, 04103, Leipzig, Germany
| | - Annette G Beck-Sickinger
- Faculty of Life Sciences, Institute of Biochemistry, Universität Leipzig, Brüderstrasse 34, 04103, Leipzig, Germany
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18
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Gardelli C, Wada H, Ray A, Caffrey M, Llinas A, Shamovsky I, Tholander J, Larsson J, Sivars U, Hultin L, Andersson U, Sanganee HJ, Stenvall K, Leidvik B, Gedda K, Jinton L, Rydén Landergren M, Karabelas K. Identification and Pharmacological Profile of an Indane Based Series of Ghrelin Receptor Full Agonists. J Med Chem 2018; 61:5974-5987. [PMID: 29909635 DOI: 10.1021/acs.jmedchem.8b00322] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cachexia and muscle wasting are very common among patients suffering from cancer, chronic obstructive pulmonary disease, and other chronic diseases. Ghrelin stimulates growth hormone secretion via the ghrelin receptor, which subsequently leads to increase of IGF-1 plasma levels. The activation of the GH/IGF-1 axis leads to an increase of muscle mass and functional capacity. Ghrelin further acts on inflammation, appetite, and adipogenesis and for this reason was considered an important target to address catabolic conditions. We report the synthesis and properties of an indane based series of ghrelin receptor full agonists; they have been shown to generate a sustained increase of IGF-1 levels in dog and have been thoroughly investigated with respect to their functional activity.
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Affiliation(s)
| | | | | | | | | | | | - Joakim Tholander
- Medicinal Chemistry Department, Cardiovascular and Metabolic Diseases IMED Biotech Unit , AstraZeneca Gothenburg , 43183 Mölndal , Sweden
| | | | | | - Leif Hultin
- Precision Medicine Laboratories, Precision Medicine and Genomics IMED Biotech Unit , AstraZeneca Gothenburg , 43183 Mölndal , Sweden
| | - Ulf Andersson
- Drug Safety and Metabolism IMED Biotech Unit , AstraZeneca Gothenburg , 43183 Mölndal , Sweden
| | - Hitesh J Sanganee
- Scientific Partnering & Alliances IMED Biotech Unit , AstraZeneca , SK10 4TF Cambridge , United Kingdom
| | | | - Brith Leidvik
- Discovery Sciences IMED Biotech Unit , AstraZeneca Gothenburg , 43183 Mölndal , Sweden
| | - Karin Gedda
- Discovery Sciences IMED Biotech Unit , AstraZeneca Gothenburg , 43183 Mölndal , Sweden
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19
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Ramirez VT, van Oeffelen WEPA, Torres-Fuentes C, Chruścicka B, Druelle C, Golubeva AV, van de Wouw M, Dinan TG, Cryan JF, Schellekens H. Differential functional selectivity and downstream signaling bias of ghrelin receptor antagonists and inverse agonists. FASEB J 2018; 33:518-531. [PMID: 30020830 DOI: 10.1096/fj.201800655r] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The ghrelin receptor [growth hormone secretagogue receptor (GHSR)-1a] represents a promising pharmacologic target for the treatment of metabolic disorders, including obesity and cachexia, via central appetite modulation. The GHSR-1a has a complex pharmacology, highlighted by G-protein-dependent and -independent downstream signaling pathways and high basal constitutive activity. The functional selectivity and signaling bias of many GHSR-1a-specific ligands has not been fully characterized. In this study, we investigated the pharmacologic properties of ghrelin, MK-0677, L692,585, and [d-Lys3]-growth hormone-releasing peptide-6 (Dlys), JMV2959, and [d-Arg(1),d-Phe(5),d-Trp(7, 9),Leu(11)]-substance P (SP-analog). We investigated their effect on basal GHSR-1a constitutive signaling, ligand-directed downstream GHSR-1a signaling, functional selectivity, and signaling bias. Dlys behaved as a partial antagonist with a strong bias toward GHSR-1a-β-arrestin signaling, whereas JMV2959 acted as a full unbiased GHSR-1a antagonist. Moreover, the SP-analog behaved as an inverse agonist increasing G-protein-dependent signaling, but only at high concentrations, whereas, at low concentrations, the SP-analog attenuated β-arrestin-dependent signaling. Considering the limited success in the clinical development of GHSR-1a-targeted drugs so far, these findings provide a novel insight into the pharmacologic characteristics of GHSR-1a ligands and their signaling bias, which has important implications in the design of novel, more selective GHSR-1a ligands with predictable functional outcome and selectivity for preclinical and clinical drug development.-Ramirez, V. T., van Oeffelen, W. E. P. A., Torres-Fuentes, C., Chruścicka, B., Druelle, C., Golubeva, A. V., van de Wouw, M., Dinan, T. G., Cryan, J. F., Schellekens, H. Differential functional selectivity and downstream signaling bias of ghrelin receptor antagonists and inverse agonists.
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Affiliation(s)
- Valerie T Ramirez
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | | | - Cristina Torres-Fuentes
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | - Barbara Chruścicka
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | - Clementine Druelle
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | - Anna V Golubeva
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | - Marcel van de Wouw
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Timothy G Dinan
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Psychiatry, University College Cork, Cork, Ireland; and
| | - John F Cryan
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.,Food for Health Ireland, University College Cork, Cork, Ireland
| | - Harriët Schellekens
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.,Food for Health Ireland, University College Cork, Cork, Ireland
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20
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Abstract
Ghrelin and motilin are released from gastrointestinal endocrine cells during hunger, to act through G protein-coupled receptors that have closely related amino acid sequences. The actions of ghrelin are more complex than motilin because ghrelin also exists outside the GI tract, it is processed to des-acyl ghrelin which has activity, ghrelin can exist in truncated forms and retain activity, the ghrelin receptor can have constitutive activity and is subject to biased agonism and finally additional ghrelin-like and des-acyl ghrelin receptors are proposed. Both ghrelin and motilin can stimulate gastric emptying, acting via different pathways, perhaps influenced by biased agonism at the receptors, but research is revealing additional pathways of activity. For example, it is becoming apparent that reduction of nausea may be a key therapeutic target for ghrelin receptor agonists and perhaps for compounds that modulate the constitutive activity of the ghrelin receptor. Reduction of nausea may be the mechanism through which gastroparesis symptoms are reduced. Intriguingly, a potential ability of motilin to influence nausea is also becoming apparent. Ghrelin interacts with digestive function through its effects on appetite, and ghrelin antagonists may have a place in treating Prader-Willi syndrome. Unlike motilin, ghrelin receptor agonists also have the potential to treat constipation by acting at the lumbosacral defecation centres. In conclusion, agonists of both ghrelin and motilin receptors hold potential as treatments for specific subsets of digestive system disorders.
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21
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Els-Heindl S, Bellmann-Sickert K, Beck-Sickinger AG. C-terminus of a hexapeptidic ghrelin receptor inverse agonist can switch peptide behavior from inverse agonism to agonism. Biopolymers 2017; 106:101-8. [PMID: 26566778 DOI: 10.1002/bip.22768] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/05/2015] [Accepted: 11/09/2015] [Indexed: 11/10/2022]
Abstract
Subtle changes in the sequence at the N-terminus and in the aromatic core of hexapeptidic ghrelin receptor inverse agonists can switch behavior from inverse agonism to agonism, but the C-terminal role of the sequence is unclear. Thus, analogs of the ghrelin receptor inverse agonist KbFwLL-NH2 (b = β-(3-benzothienyl)-d-alanine) were synthesized by solid phase peptide synthesis in order to identify the influence of aromaticity, charge, and hydrophobicity. Potency and efficacy of the hexapeptides were evaluated in inositol triphosphate turnover assays. Notably, modifications directly at the C-terminal Leu(6) could influence peptide efficacy leading to decreased constitutive activity. High hydrophobicity at the C-terminal position was of importance for elevated inverse agonist activity, the introduction of charged amino acids led to decreased potency. In contrast, structure-activity relationship studies of Leu(5) located closer to the aromatic core revealed an agonism-inducing position. These findings imply that amino acids with possible cation-π or π-π interactions and a suitable orientation at the C-terminus of the aromatic core induce agonism. Receptor binding studies showed that most peptides bind to the receptor at a concentration of 1 µM and modification directly at the C-terminus is generally more accepted than Leu(5) substitution. Interestingly, this observation is not dependent on the type of modification. These studies reveal another switch region of the short ghrelin receptor ligand pointing out the sensitivity of the ghrelin receptor binding pocket.
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Affiliation(s)
- Sylvia Els-Heindl
- Faculty of Biosciences, Pharmacy and Psychology, Institute of Biochemistry, Universität Leipzig, Brüderstraße 34, Leipzig, 04103, Germany
| | - Kathrin Bellmann-Sickert
- Faculty of Biosciences, Pharmacy and Psychology, Institute of Biochemistry, Universität Leipzig, Brüderstraße 34, Leipzig, 04103, Germany
| | - Annette G Beck-Sickinger
- Faculty of Biosciences, Pharmacy and Psychology, Institute of Biochemistry, Universität Leipzig, Brüderstraße 34, Leipzig, 04103, Germany
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22
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Hou J, Charron CL, Fowkes MM, Luyt LG. Bridging computational modeling with amino acid replacements to investigate GHS-R1a-peptidomimetic recognition. Eur J Med Chem 2016; 123:822-833. [DOI: 10.1016/j.ejmech.2016.07.078] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/13/2016] [Accepted: 07/31/2016] [Indexed: 12/26/2022]
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23
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Gorwood P, Blanchet-Collet C, Chartrel N, Duclos J, Dechelotte P, Hanachi M, Fetissov S, Godart N, Melchior JC, Ramoz N, Rovere-Jovene C, Tolle V, Viltart O, Epelbaum J. New Insights in Anorexia Nervosa. Front Neurosci 2016; 10:256. [PMID: 27445651 PMCID: PMC4925664 DOI: 10.3389/fnins.2016.00256] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 05/23/2016] [Indexed: 12/18/2022] Open
Abstract
Anorexia nervosa (AN) is classically defined as a condition in which an abnormally low body weight is associated with an intense fear of gaining weight and distorted cognitions regarding weight, shape, and drive for thinness. This article reviews recent evidences from physiology, genetics, epigenetics, and brain imaging which allow to consider AN as an abnormality of reward pathways or an attempt to preserve mental homeostasis. Special emphasis is put on ghrelino-resistance and the importance of orexigenic peptides of the lateral hypothalamus, the gut microbiota and a dysimmune disorder of neuropeptide signaling. Physiological processes, secondary to underlying, and premorbid vulnerability factors-the "pondero-nutritional-feeding basements"- are also discussed.
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Affiliation(s)
- Philip Gorwood
- Centre Hospitalier Sainte-Anne (CMME)Paris, France; UMR-S 894, Institut National de la Santé et de la Recherche Médicale, Centre de Psychiatrie et NeurosciencesParis, France; Université Paris Descartes, Sorbonne Paris CitéParis, France
| | | | - Nicolas Chartrel
- Institut National de la Santé et de la Recherche Médicale U982, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Institute for Research and Innovation in BiomedicineRouen, France; Normandy UniversityCaen, France; University of RouenRouen, France
| | - Jeanne Duclos
- Adolescents and Young Adults Psychiatry Department, Institut Mutualiste MontsourisParis, France; CESP, Institut National de la Santé et de la Recherche Médicale, Université Paris-Descartes, USPCParis, France; University Reims, Champagne-Ardenne, Laboratoire Cognition, Santé, Socialisation (C2S)-EA 6291Reims, France
| | - Pierre Dechelotte
- Institut National de la Santé et de la Recherche Médicale U1073 IRIB Normandy UniversityRouen, France; Faculté de Médecine-PharmacieRouen, France
| | - Mouna Hanachi
- Université de Versailles Saint-Quentin-en-Yvelines, Institut National de la Santé et de la Recherche Médicale U1179, équipe Thérapeutiques Innovantes et Technologies Appliquées aux Troubles Neuromoteurs, UFR des Sciences de la Santé Simone VeilMontigny-le-Bretonneux, France; Département de Médecine (Unité de Nutrition), Hôpital Raymond Poincaré, Assistance Publique-Hôpitaux de ParisGarches, France
| | - Serguei Fetissov
- Institut National de la Santé et de la Recherche Médicale U1073 IRIB Normandy University Rouen, France
| | - Nathalie Godart
- Adolescents and Young Adults Psychiatry Department, Institut Mutualiste MontsourisParis, France; CESP, Institut National de la Santé et de la Recherche Médicale, Université Paris-Descartes, USPCParis, France
| | - Jean-Claude Melchior
- Université de Versailles Saint-Quentin-en-Yvelines, Institut National de la Santé et de la Recherche Médicale U1179, équipe Thérapeutiques Innovantes et Technologies Appliquées aux Troubles Neuromoteurs, UFR des Sciences de la Santé Simone VeilMontigny-le-Bretonneux, France; Département de Médecine (Unité de Nutrition), Hôpital Raymond Poincaré, Assistance Publique-Hôpitaux de ParisGarches, France
| | - Nicolas Ramoz
- UMR-S 894, Institut National de la Santé et de la Recherche Médicale, Centre de Psychiatrie et NeurosciencesParis, France; Université Paris Descartes, Sorbonne Paris CitéParis, France
| | - Carole Rovere-Jovene
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR6097, Centre National de la Recherche Scientifique Valbonne, France
| | - Virginie Tolle
- UMR-S 894, Institut National de la Santé et de la Recherche Médicale, Centre de Psychiatrie et NeurosciencesParis, France; Université Paris Descartes, Sorbonne Paris CitéParis, France
| | - Odile Viltart
- Université Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc - Centre de Recherche Jean-Pierre AUBERT Neurosciences et Cancer Lille, France
| | - Jacques Epelbaum
- UMR-S 894, Institut National de la Santé et de la Recherche Médicale, Centre de Psychiatrie et NeurosciencesParis, France; Université Paris Descartes, Sorbonne Paris CitéParis, France
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24
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Maingot M, Blayo AL, Denoyelle S, M'Kadmi C, Damian M, Mary S, Gagne D, Sanchez P, Aicher B, Schmidt P, Müller G, Teifel M, Günther E, Marie J, Banères JL, Martinez J, Fehrentz JA. New ligands of the ghrelin receptor based on the 1,2,4-triazole scaffold by introduction of a second chiral center. Bioorg Med Chem Lett 2016; 26:2408-2412. [PMID: 27072910 DOI: 10.1016/j.bmcl.2016.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/01/2016] [Accepted: 04/03/2016] [Indexed: 12/25/2022]
Abstract
Introducing a second chiral center on our previously described 1,2,4-triazole, allowed us to increase diversity and elongate the 'C-terminal part' of the molecule. Therefore, we were able to explore mimics of the substance P analogs described as inverse agonists. Some compounds presented affinities in the nanomolar range and potent biological activities, while one exhibited a partial inverse agonist behavior similar to a Substance P analog.
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Affiliation(s)
- Mathieu Maingot
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, ENSCM, Université de Montpellier, BP 14491, Faculté de Pharmacie, bât. E, 3(ème) étage, 15 avenue Charles Flahault, 34093 Montpellier Cedex 5, France
| | - Anne-Laure Blayo
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, ENSCM, Université de Montpellier, BP 14491, Faculté de Pharmacie, bât. E, 3(ème) étage, 15 avenue Charles Flahault, 34093 Montpellier Cedex 5, France
| | - Séverine Denoyelle
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, ENSCM, Université de Montpellier, BP 14491, Faculté de Pharmacie, bât. E, 3(ème) étage, 15 avenue Charles Flahault, 34093 Montpellier Cedex 5, France
| | - Céline M'Kadmi
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, ENSCM, Université de Montpellier, BP 14491, Faculté de Pharmacie, bât. E, 3(ème) étage, 15 avenue Charles Flahault, 34093 Montpellier Cedex 5, France
| | - Marjorie Damian
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, ENSCM, Université de Montpellier, BP 14491, Faculté de Pharmacie, bât. E, 3(ème) étage, 15 avenue Charles Flahault, 34093 Montpellier Cedex 5, France
| | - Sophie Mary
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, ENSCM, Université de Montpellier, BP 14491, Faculté de Pharmacie, bât. E, 3(ème) étage, 15 avenue Charles Flahault, 34093 Montpellier Cedex 5, France
| | - Didier Gagne
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, ENSCM, Université de Montpellier, BP 14491, Faculté de Pharmacie, bât. E, 3(ème) étage, 15 avenue Charles Flahault, 34093 Montpellier Cedex 5, France
| | - Pierre Sanchez
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, ENSCM, Université de Montpellier, BP 14491, Faculté de Pharmacie, bât. E, 3(ème) étage, 15 avenue Charles Flahault, 34093 Montpellier Cedex 5, France
| | - Babette Aicher
- Æterna Zentaris GmbH, Weismuellerstrasse 50, 60314 Frankfurt am Main, Germany
| | - Peter Schmidt
- Æterna Zentaris GmbH, Weismuellerstrasse 50, 60314 Frankfurt am Main, Germany
| | - Gilbert Müller
- Æterna Zentaris GmbH, Weismuellerstrasse 50, 60314 Frankfurt am Main, Germany
| | - Michael Teifel
- Æterna Zentaris GmbH, Weismuellerstrasse 50, 60314 Frankfurt am Main, Germany
| | - Eckhard Günther
- Æterna Zentaris GmbH, Weismuellerstrasse 50, 60314 Frankfurt am Main, Germany
| | - Jacky Marie
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, ENSCM, Université de Montpellier, BP 14491, Faculté de Pharmacie, bât. E, 3(ème) étage, 15 avenue Charles Flahault, 34093 Montpellier Cedex 5, France
| | - Jean-Louis Banères
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, ENSCM, Université de Montpellier, BP 14491, Faculté de Pharmacie, bât. E, 3(ème) étage, 15 avenue Charles Flahault, 34093 Montpellier Cedex 5, France
| | - Jean Martinez
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, ENSCM, Université de Montpellier, BP 14491, Faculté de Pharmacie, bât. E, 3(ème) étage, 15 avenue Charles Flahault, 34093 Montpellier Cedex 5, France
| | - Jean-Alain Fehrentz
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, ENSCM, Université de Montpellier, BP 14491, Faculté de Pharmacie, bât. E, 3(ème) étage, 15 avenue Charles Flahault, 34093 Montpellier Cedex 5, France.
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25
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Kakarala KK, Jamil K. Biased signaling: potential agonist and antagonist of PAR2. J Biomol Struct Dyn 2015; 34:1363-76. [DOI: 10.1080/07391102.2015.1079556] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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26
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M'Kadmi C, Leyris JP, Onfroy L, Galés C, Saulière A, Gagne D, Damian M, Mary S, Maingot M, Denoyelle S, Verdié P, Fehrentz JA, Martinez J, Banères JL, Marie J. Agonism, Antagonism, and Inverse Agonism Bias at the Ghrelin Receptor Signaling. J Biol Chem 2015; 290:27021-27039. [PMID: 26363071 DOI: 10.1074/jbc.m115.659250] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Indexed: 01/14/2023] Open
Abstract
The G protein-coupled receptor GHS-R1a mediates ghrelin-induced growth hormone secretion, food intake, and reward-seeking behaviors. GHS-R1a signals through Gq, Gi/o, G13, and arrestin. Biasing GHS-R1a signaling with specific ligands may lead to the development of more selective drugs to treat obesity or addiction with minimal side effects. To delineate ligand selectivity at GHS-R1a signaling, we analyzed in detail the efficacy of a panel of synthetic ligands activating the different pathways associated with GHS-R1a in HEK293T cells. Besides β-arrestin2 recruitment and ERK1/2 phosphorylation, we monitored activation of a large panel of G protein subtypes using a bioluminescence resonance energy transfer-based assay with G protein-activation biosensors. We first found that unlike full agonists, Gq partial agonists were unable to trigger β-arrestin2 recruitment and ERK1/2 phosphorylation. Using G protein-activation biosensors, we then demonstrated that ghrelin promoted activation of Gq, Gi1, Gi2, Gi3, Goa, Gob, and G13 but not Gs and G12. Besides, we identified some GHS-R1a ligands that preferentially activated Gq and antagonized ghrelin-mediated Gi/Go activation. Finally, we unambiguously demonstrated that in addition to Gq, GHS-R1a also promoted constitutive activation of G13. Importantly, we identified some ligands that were selective inverse agonists toward Gq but not of G13. This demonstrates that bias at GHS-R1a signaling can occur not only with regard to agonism but also to inverse agonism. Our data, combined with other in vivo studies, may facilitate the design of drugs selectively targeting individual signaling pathways to treat only the therapeutically relevant function.
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Affiliation(s)
- Céline M'Kadmi
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 05
| | - Jean-Philippe Leyris
- the Institut des Neurosciences de Montpellier, Hôpital Saint-Eloi, 80 Avenue Augustin Fliche, BP 74103, 34091 Montpellier Cedex 05
| | - Lauriane Onfroy
- the Institut des Maladies Métaboliques et Cardiovasculaires, INSERM, U1048, Université Toulouse III Paul Sabatier, Centre Hospitalier Universitaire de Toulouse, 31432 Toulouse, France
| | - Céline Galés
- the Institut des Maladies Métaboliques et Cardiovasculaires, INSERM, U1048, Université Toulouse III Paul Sabatier, Centre Hospitalier Universitaire de Toulouse, 31432 Toulouse, France
| | - Aude Saulière
- the Institut des Maladies Métaboliques et Cardiovasculaires, INSERM, U1048, Université Toulouse III Paul Sabatier, Centre Hospitalier Universitaire de Toulouse, 31432 Toulouse, France
| | - Didier Gagne
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 05
| | - Marjorie Damian
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 05
| | - Sophie Mary
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 05
| | - Mathieu Maingot
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 05
| | - Séverine Denoyelle
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 05
| | - Pascal Verdié
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 05
| | - Jean-Alain Fehrentz
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 05
| | - Jean Martinez
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 05
| | - Jean-Louis Banères
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 05
| | - Jacky Marie
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 05,.
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Ibrahim Abdalla MM. Ghrelin - Physiological Functions and Regulation. EUROPEAN ENDOCRINOLOGY 2015; 11:90-95. [PMID: 29632576 DOI: 10.17925/ee.2015.11.02.90] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 07/13/2015] [Indexed: 01/01/2023]
Abstract
Ghrelin is an orexigenic peptide predominantly secreted from the stomach and stimulates appetite and growth hormone (GH) release. Studies have provided evidence that ghrelin exercises a wide range of functions, including regulation of food intake and energy metabolism, modulation of cardiovascular function, stimulation of osteoblast proliferation and bone formation and stimulation of neurogenesis and myogenesis. In the gastrointestinal system, ghrelin affects multiple functions, including secretion of gastric acid, gastric motility and pancreatic protein output. Most of these functions have been attributed to the actions of acylated ghrelin. The balance among its secretion rate, degradation rate and clearance rate determines the circulating level of ghrelin. This review explains what ghrelin is, its physiological functions and the factors that influence its level.
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Kilian TM, Klöting N, Bergmann R, Els-Heindl S, Babilon S, Clément-Ziza M, Zhang Y, Beck-Sickinger AG, Chollet C. Rational design of dual peptides targeting ghrelin and Y2 receptors to regulate food intake and body weight. J Med Chem 2015; 58:4180-93. [PMID: 25905598 DOI: 10.1021/jm501702q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Ghrelin and Y2 receptors play a central role in appetite regulation inducing opposite effects. The Y2 receptor induces satiety, while the ghrelin receptor promotes hunger and weight gain. However, the food regulating system is tightly controlled by interconnected pathways where redundancies can lead to poor efficacy and drug tolerance when addressing a single molecule. We developed a multitarget strategy to synthesize dual peptides simultaneously inhibiting the ghrelin receptor and stimulating the Y2 receptor. Dual peptides showed dual activity in vitro, and one compound induced a slight diminution of food intake in a rodent model of obesity. In addition, stability studies in rats revealed different behaviors between the dual peptide and its corresponding monomers. The Y2 receptor agonist was unstable in blood, while the dual peptide showed an intermediate stability compared to that of the highly stable ghrelin receptor inverse agonist.
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Affiliation(s)
- Tom-Marten Kilian
- †Faculty of Biosciences, Pharmacy and Psychology, Institute of Biochemistry, Universität Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany
| | - Nora Klöting
- ‡Integrated Research and Treatment Center Adiposity Diseases (IFB), Core Unit "Animal Models", Universität Leipzig, Liebigstrasse 21, 04103 Leipzig, Germany
| | - Ralf Bergmann
- §Department of Radiopharmaceutical and Chemical Biology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany
| | - Sylvia Els-Heindl
- †Faculty of Biosciences, Pharmacy and Psychology, Institute of Biochemistry, Universität Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany
| | - Stefanie Babilon
- †Faculty of Biosciences, Pharmacy and Psychology, Institute of Biochemistry, Universität Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany
| | - Mathieu Clément-Ziza
- ∥CECAD - Cluster of Excellence, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Yixin Zhang
- ⊥B CUBE-Center for Molecular Bioengineering, Technische Universität Dresden, Arnoldstrasse 18, 01307 Dresden, Germany
| | - Annette G Beck-Sickinger
- †Faculty of Biosciences, Pharmacy and Psychology, Institute of Biochemistry, Universität Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany
| | - Constance Chollet
- †Faculty of Biosciences, Pharmacy and Psychology, Institute of Biochemistry, Universität Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany.,⊥B CUBE-Center for Molecular Bioengineering, Technische Universität Dresden, Arnoldstrasse 18, 01307 Dresden, Germany
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29
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High metabolic in vivo stability and bioavailability of a palmitoylated ghrelin receptor ligand assessed by mass spectrometry. Bioorg Med Chem 2014; 23:3925-32. [PMID: 25541202 DOI: 10.1016/j.bmc.2014.12.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/30/2014] [Accepted: 12/04/2014] [Indexed: 11/20/2022]
Abstract
The constitutive activity of the ghrelin receptor is of high physiological and pathophysiological relevance. In-depth structure-activity relationship studies revealed a palmitoylated ghrelin receptor ligand that displays an in vitro binding affinity in the low nanomolar range. Activity studies revealed inverse agonistic as well as antagonistic properties and in vitro metabolic analysis indicated a high stability in blood serum and liver homogenate. For metabolic testing in vivo, a combined approach of stable isotopic labeling and mass spectrometry-based analysis was established. Therefore, a heavy isotopic version of the peptide containing a (13)C-labeled palmitic acid was synthesized and a 1:1 ratio of a (12)C/(13)C-peptide mixture was injected into rats. Biological samples were analyzed by multiple reaction monitoring allowing simultaneous peptide detection and quantification. Measurements revealed a suitable bioavailability over 24h in rat serum and subsequent high-resolution mass spectrometry investigations showed only negligible degradation and slow body clearance. Hence, this method combination allowed the identification and evaluation of a highly potent and metabolically stable ghrelin receptor ligand in vivo.
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Mear Y, Blanchard MP, Defilles C, Brue T, Figarella-Branger D, Graillon T, Manavela M, Barlier A, Enjalbert A, Thirion S. Ghrelin receptor (GHS-R1a) and its constitutive activity in somatotroph adenomas: a new co-targeting therapy using GHS-R1a inverse agonists and somatostatin analogs. J Clin Endocrinol Metab 2014; 99:E2463-71. [PMID: 25272306 DOI: 10.1210/jc.2014-2753] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
CONTEXT The ghrelin receptor GHS-R1a is highly expressed in human somatotroph adenomas and exhibits unusually high basal signaling activity. In humans, the suppression of this constitutive activity by mutation induces a short stature. OBJECTIVE Using a GHS-R1a inverse agonist, modified substance P (MSP), we explored the role of GHS-R1a constitutive activity in GH hypersecretion from somatotroph adenomas and as a putative therapeutic target. DESIGN The effects of MSP were assessed on GH secretion from 19 human somatotroph tumors in vitro. Moreover, these effects were compared with those of octreotide (somatostatin receptor subtype 2 [sst2] agonist) and with the combination of both drugs. Expression and localization of GHS-R1a and sst2 were studied. RESULTS For all tumors, MSP inhibited GH secretion in a dose-dependent manner from 13 to 64%. Moreover, MSP enhanced octreotide-induced GH inhibition. For five tumors, the effects of combined MSP plus octreotide treatment were significantly higher than the sum of effects of each drug alone. MSP increased the membrane localization of GHS-R1a and of microdomains colocalizing sst2-GHS-R1a, highlighting the cooperation between the two drugs. CONCLUSIONS The GHS-R1a inverse agonist could open new therapeutic options for acromegalic patients, particularly patients partially sensitive to octreotide whose GH secretion is not completely controlled by the sst2 agonist.
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Affiliation(s)
- Yves Mear
- Aix-Marseille University (Y.M., M.-P.B., C.D., T.B., T.G., A.B., A.E., S.T.), Centre National de la Recherche Scientifique, CRN2M UMR7286, 13344 Marseille, France; APHM, Conception (A.B., A.E.), Laboratory of Molecular Biology, 13385 Marseille, France; APHM, Timone, Department of Endocrinology (T.B.), Department of Neurosurgery (T.G.), and Laboratory of Neuropathology (D.F.-B.), 13385 Marseille, France; Aix-Marseille University (D.F.-B.), INSERM, CRO2 UMR911, 13385 Marseille, France; and Buenos Aires University (M.M.), Department of Endocrinology, Hospital de Clinicas, Buenos Aires 1120, Argentina
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Sivertsen B, Holliday N, Madsen AN, Holst B. Functionally biased signalling properties of 7TM receptors - opportunities for drug development for the ghrelin receptor. Br J Pharmacol 2014; 170:1349-62. [PMID: 24032557 DOI: 10.1111/bph.12361] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 06/17/2013] [Accepted: 08/06/2013] [Indexed: 12/23/2022] Open
Abstract
UNLABELLED The ghrelin receptor is a 7 transmembrane (7TM) receptor involved in a variety of physiological functions including growth hormone secretion, increased food intake and fat accumulation as well as modulation of reward and cognitive functions. Because of its important role in metabolism and energy expenditure, the ghrelin receptor has become an important therapeutic target for drug design and the development of anti-obesity compounds. However, none of the compounds developed so far have been approved for commercial use. Interestingly, the ghrelin receptor is able to signal through several different signalling pathways including Gαq , Gαi/o , Gα12/13 and arrestin recruitment. These multiple signalling pathways allow for functionally biased signalling, where one signalling pathway may be favoured over another either by selective ligands or through mutations in the receptor. In the present review, we have described how ligands and mutations in the 7TM receptor may bias the receptors to favour either one G-protein over another or to promote G-protein independent signalling pathways rather than G-protein-dependent pathways. For the ghrelin receptor, both agonist and inverse agonists have been demonstrated to signal more strongly through the Gαq -coupled pathway than the Gα12/13 -coupled pathway. Similarly a ligand that promotes Gαq coupling over Gαi coupling has been described and it has been suggested that several different active conformations of the receptor may exist dependent on the properties of the agonist. Importantly, ligands with such biased signalling properties may allow the development of drugs that selectively modulate only the therapeutically relevant physiological functions, thereby decreasing the risk of side effects. LINKED ARTICLES This article is part of a themed section on Neuropeptides. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.170.issue-7.
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Affiliation(s)
- B Sivertsen
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, the Panum Institute, University of Copenhagen, Copenhagen, Denmark
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32
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Callaghan B, Furness JB. Novel and Conventional Receptors for Ghrelin, Desacyl-Ghrelin, and Pharmacologically Related Compounds. Pharmacol Rev 2014; 66:984-1001. [DOI: 10.1124/pr.113.008433] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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Cameron KO, Bhattacharya SK, Loomis AK. Small Molecule Ghrelin Receptor Inverse Agonists and Antagonists. J Med Chem 2014; 57:8671-91. [DOI: 10.1021/jm5003183] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Kimberly O. Cameron
- Worldwide
Medicinal Chemistry, Pfizer Worldwide Research and Development, 610
Main Street, Cambridge, Massachusetts 02139, United States
| | - Samit K. Bhattacharya
- Worldwide
Medicinal Chemistry, Pfizer Worldwide Research and Development, 610
Main Street, Cambridge, Massachusetts 02139, United States
| | - A. Katrina Loomis
- Pharmatherapeutics
Precision Medicine, Pfizer Worldwide Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
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34
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Sanger GJ. Ghrelin and motilin receptor agonists: time to introduce bias into drug design. Neurogastroenterol Motil 2014; 26:149-55. [PMID: 24438586 DOI: 10.1111/nmo.12300] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 12/11/2013] [Indexed: 02/08/2023]
Abstract
Ghrelin and motilin receptor agonists increase gastric motility and are attractive drug targets. However, 14 years after the receptors were described (18-24 years since ligands became available) the inactivity of the ghrelin agonist TZP-102 in patients with gastroparesis joins the list of unsuccessful motilin agonists. Fundamental questions must be asked. Pustovit et al., have now shown that the ghrelin agonist ulimorelin evokes prolonged increases in rat colorectal propulsion yet responses to other ghrelin agonists fade. Similarly, different motilin agonists induce short- or long-lasting effects in a cell-dependent manner. Together, these and other data create the hypothesis that the receptors can be induced to preferentially signal ('biased agonism') via particular pathways to evoke different responses with therapeutic advantages/disadvantages. Biased agonism has been demonstrated for ghrelin. Are motilin agonists which cause long-lasting facilitation of human stomach cholinergic function (compared with motilin) biased agonists (e.g., camicinal, under development for patients with gastric hypo-motility)? For ghrelin, additional complications exist because the therapeutic aims/mechanisms of action are uncertain, making it difficult to select the best (biased) agonist. Will ghrelin agonists be useful treatments of nausea and/or as suggested by Pustovit et al., chronic constipation? How does ghrelin increase gastric motility? As gastroparesis symptoms poorly correlate with delayed gastric emptying (yet gastro-prokinetic drugs can provide relief: e.g., low-dose erythromycin), would low doses of ghrelin and motilin agonists relieve symptoms simply by restoring neuromuscular rhythm? These questions on design and functions need addressing if ghrelin and motilin agonists are to reach patients as drugs.
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Affiliation(s)
- G J Sanger
- Neurogastroenterology Group, Blizard Institute, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
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35
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Fenalti G, Giguere PM, Katritch V, Huang XP, Thompson AA, Cherezov V, Roth BL, Stevens RC. Molecular control of δ-opioid receptor signalling. Nature 2014; 506:191-6. [PMID: 24413399 DOI: 10.1038/nature12944] [Citation(s) in RCA: 383] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 12/06/2013] [Indexed: 01/12/2023]
Abstract
Opioids represent widely prescribed and abused medications, although their signal transduction mechanisms are not well understood. Here we present the 1.8 Å high-resolution crystal structure of the human δ-opioid receptor (δ-OR), revealing the presence and fundamental role of a sodium ion in mediating allosteric control of receptor functional selectivity and constitutive activity. The distinctive δ-OR sodium ion site architecture is centrally located in a polar interaction network in the seven-transmembrane bundle core, with the sodium ion stabilizing a reduced agonist affinity state, and thereby modulating signal transduction. Site-directed mutagenesis and functional studies reveal that changing the allosteric sodium site residue Asn 131 to an alanine or a valine augments constitutive β-arrestin-mediated signalling. Asp95Ala, Asn310Ala and Asn314Ala mutations transform classical δ-opioid antagonists such as naltrindole into potent β-arrestin-biased agonists. The data establish the molecular basis for allosteric sodium ion control in opioid signalling, revealing that sodium-coordinating residues act as 'efficacy switches' at a prototypic G-protein-coupled receptor.
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Affiliation(s)
- Gustavo Fenalti
- 1] Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA [2]
| | - Patrick M Giguere
- 1] National Institute of Mental Health Psychoactive Drug Screening Program and Department of Pharmacology and Division of Chemical Biology and Medicinal Chemistry, University of North Carolina Chapel Hill Medical School, Chapel Hill, North Carolina 27599, USA [2]
| | - Vsevolod Katritch
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Xi-Ping Huang
- National Institute of Mental Health Psychoactive Drug Screening Program and Department of Pharmacology and Division of Chemical Biology and Medicinal Chemistry, University of North Carolina Chapel Hill Medical School, Chapel Hill, North Carolina 27599, USA
| | - Aaron A Thompson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Vadim Cherezov
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Bryan L Roth
- National Institute of Mental Health Psychoactive Drug Screening Program and Department of Pharmacology and Division of Chemical Biology and Medicinal Chemistry, University of North Carolina Chapel Hill Medical School, Chapel Hill, North Carolina 27599, USA
| | - Raymond C Stevens
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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36
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Chalikiopoulos A, Thiele S, Malmgaard-Clausen M, Rydberg P, Isberg V, Ulven T, Frimurer TM, Rosenkilde MM, Gloriam DE. Structure-activity relationships and identification of optmized CC-chemokine receptor CCR1, 5, and 8 metal-ion chelators. J Chem Inf Model 2013; 53:2863-73. [PMID: 24083637 DOI: 10.1021/ci4003848] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chemokine receptors are involved in trafficking of leukocytes and represent targets for autoimmune conditions, inflammatory diseases, viral infections, and cancer. We recently published CCR1, CCR8, and CCR5 agonists and positive modulators based on a three metal-ion chelator series: 2,2'-bipyridine, 1,10-phenanthroline, and 2,2';6',2″-terpyridine. Here, we have performed an in-depth structure-activity relationship study and tested eight new optimized analogs. Using density functional theory calculations we demonstrate that the chelator zinc affinities depend on how electron-donating and -withdrawing substituents modulate the partial charges of chelating nitrogens. The zinc affinity was found to constitute the major factor for receptor potency, although the activity of some chelators deviate suggesting favorable or unfavorable interactions. Hydrophobic and halogen substituents are generally better accommodated in the receptors than polar groups. The new analog brominated terpyridine (29) resulted in the highest chelator potencies observed so far CCR1 (EC50: 0.49 μM) and CCR8 (EC50: 0.28 μM). Furthermore, we identified the first selective CCR5 agonist chelator, meta dithiomethylated bipyridine (23). The structure-activity relationships contribute to small-molecule drug development, and the novel chelators constitute valuable tools for studies of structural mechanisms for chemokine receptor activation.
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Affiliation(s)
- Alexander Chalikiopoulos
- Department of Drug Design and Pharmacology, ‡Department of Neuroscience and Pharmacology and ⊥The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen , DK-1165 Copenhagen, Denmark
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37
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Mear Y, Enjalbert A, Thirion S. GHS-R1a constitutive activity and its physiological relevance. Front Neurosci 2013; 7:87. [PMID: 23754971 PMCID: PMC3665924 DOI: 10.3389/fnins.2013.00087] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 05/09/2013] [Indexed: 12/14/2022] Open
Abstract
Abundant evidences have shown that ghrelin, by its binding to GHS-R1a, plays an important role for fundamental physiological functions. Increasing attention is given to the GHS-R1a unusually high constitutive activity and its contribution to downstream signaling and physiological processes. Here, we review recent lines of evidences showing that the interaction between ligand-binding pocket TM domains and the ECL2 could be partially responsible for this high constitutive activity. Interestingly, GHSR-1a constitutive activity activates in turn the downstream PLC, PKC, and CRE signaling pathways and this activation is reversed by the inverse agonist [D-Arg1, D-Phe5, D-Trp7,9, Leu11]-substance P (MSP). Noteworthy, GHSR-1a exhibits a C-terminal-dependent constitutive internalization. Non-sense GHS-R1a mutation (Ala204Glu), first discovered in Moroccan patients, supports the role of GHSR-1a constitutive activity in physiological impairments. Ala204Glu-point mutation, altering exclusively the GHSR-1a constitutive activity, was associated with familial short stature syndrome. Altogether, these findings suggest that GHS-R1a constitutive activity could contribute to GH secretion or body weight regulation. Consequently, future research on basic and clinical applications of GHS-R1a inverse agonists will be challenging and potentially rewarding.
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Affiliation(s)
- Yves Mear
- CNRS, CRN2M UMR7286, Aix Marseille University Marseille, France
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38
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Steen A, Thiele S, Guo D, Hansen LS, Frimurer TM, Rosenkilde MM. Biased and constitutive signaling in the CC-chemokine receptor CCR5 by manipulating the interface between transmembrane helices 6 and 7. J Biol Chem 2013; 288:12511-21. [PMID: 23493400 DOI: 10.1074/jbc.m112.449587] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The equilibrium state of CCR5 is manipulated here toward either activation or inactivation by introduction of single amino acid substitutions in the transmembrane domains (TMs) 6 and 7. Insertion of a steric hindrance mutation in the center of TM7 (G286F in position VII:09/7.42) resulted in biased signaling. Thus, β-arrestin recruitment was eliminated, whereas constitutive activity was observed in Gαi-mediated signaling. Furthermore, the CCR5 antagonist aplaviroc was converted to a full agonist (a so-called efficacy switch). Computational modeling revealed that the position of the 7TM receptor-conserved Trp in TM6 (Trp-248 in position VI:13/6.48, part of the CWXP motif) was influenced by the G286F mutation, causing Trp-248 to change orientation away from TM7. The essential role of Trp-248 in CCR5 activation was supported by complete inactivity of W248A-CCR5 despite maintaining chemokine binding. Furthermore, replacing Trp-248 with a smaller aromatic amino acid (Tyr/Phe) impaired the β-arrestin recruitment, yet with maintained G protein activity (biased signaling); also, here aplaviroc switched to a full agonist. Thus, the altered positioning of Trp-248, induced by G286F, led to a constraint of G protein active, but β-arrestin inactive and thus biased, CCR5 conformation. These results provide important information on the molecular interplay and impact of TM6 and TM7 for CCR5 activity, which may be extrapolated to other chemokine receptors and possibly to other 7TM receptors.
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Affiliation(s)
- Anne Steen
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
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Li Z, Li Y, Zhang W. Ghrelin receptor in energy homeostasis and obesity pathogenesis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 114:45-87. [PMID: 23317782 DOI: 10.1016/b978-0-12-386933-3.00002-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ghrelin receptor, also known as growth hormone secretagogue receptor (GHS-R), was identified in porcine and rat anterior pituitary membranes, where the synthetic secretagogue MK-0677 causes amplified pulsatile growth hormone (GH) release. In addition to its function in the stimulation of GH secretion, ghrelin, the natural ligand of ghrelin receptor is now recognized as a peptide hormone with fundamental influence on energy homeostasis. Despite the potential existence of multiple subtypes of ghrelin receptor, the effects of ghrelin on energy metabolism, obesity, and diabetes are mediated by its classical receptor GHS-R1a, whose activation requires the n-octanoylation of ghrelin. Here we review the current understanding of the role of the ghrelin receptor in the regulation of energy homeostasis. An overview of the ghrelin receptor is presented first, followed by the discussion on its effects on food intake, glucose homeostasis, and lipid metabolism. Finally, potential strategies for treating obesity and diabetes via manipulation of the ghrelin/ghrelin receptor axis are explored.
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Affiliation(s)
- Ziru Li
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China
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McCoull W, Barton P, Broo A, Brown AJH, Clarke DS, Coope G, Davies RDM, Dossetter AG, Kelly EE, Knerr L, MacFaul P, Holmes JL, Martin N, Moore JE, Morgan D, Newton C, Österlund K, Robb GR, Rosevere E, Selmi N, Stokes S, Svensson TS, Ullah VBK, Williams EJ. Identification of pyrazolo-pyrimidinones as GHS-R1a antagonists and inverse agonists for the treatment of obesity. MEDCHEMCOMM 2013. [DOI: 10.1039/c2md20340e] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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41
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Valentin-Hansen L, Holst B, Frimurer TM, Schwartz TW. PheVI:09 (Phe6.44) as a sliding microswitch in seven-transmembrane (7TM) G protein-coupled receptor activation. J Biol Chem 2012; 287:43516-26. [PMID: 23135271 DOI: 10.1074/jbc.m112.395137] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In seven-transmembrane (7TM), G protein-coupled receptors, highly conserved residues function as microswitches, which alternate between different conformations and interaction partners in an extended allosteric interface between the transmembrane segments performing the large scale conformational changes upon receptor activation. Computational analysis using x-ray structures of the β(2)-adrenergic receptor demonstrated that PheVI:09 (6.44), which in the inactive state is locked between the backbone and two hydrophobic residues in transmembrane (TM)-III, upon activation slides ∼2 Å toward TM-V into a tight pocket generated by five hydrophobic residues protruding from TM-III and TM-V. Of these, the residue in position III:16 (3.40) (often an Ile or Val) appears to function as a barrier or gate for the transition between inactive and active conformation. Mutational analysis showed that PheVI:09 is essential for the constitutive and/or agonist-induced signaling of the ghrelin receptor, GPR119, the β(2)-adrenergic receptor, and the neurokinin-1 receptor. Substitution of the residues constituting the hydrophobic pocket between TM-III and TM-V in the ghrelin receptor in four of five positions impaired receptor signaling. In GPR39, representing the 12% of 7TM receptors lacking an aromatic residue at position VI:09, unchanged agonist-induced signaling was observed upon Ala substitution of LeuVI:09 despite reduced cell surface expression of the mutant receptor. It is concluded that PheVI:09 constitutes an aromatic microswitch that stabilizes the active, outward tilted conformation of TM-VI relative to TM-III by sliding into a tight hydrophobic pocket between TM-III and TM-V and that the hydrophobic residue in position III:16 constitutes a gate for this transition.
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Affiliation(s)
- Louise Valentin-Hansen
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, the Panum Institute, Copenhagen, Denmark
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42
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Els S, Schild E, Petersen PS, Kilian TM, Mokrosinski J, Frimurer TM, Chollet C, Schwartz TW, Holst B, Beck-Sickinger AG. An aromatic region to induce a switch between agonism and inverse agonism at the ghrelin receptor. J Med Chem 2012; 55:7437-49. [PMID: 22920150 DOI: 10.1021/jm300414b] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The ghrelin receptor displays a high constitutive activity suggested to be involved in the regulation of appetite and food intake. Here, we have created peptides with small changes in the core binding motif -wFw- of the hexapeptide KwFwLL-NH(2) that can swap the peptide behavior from inverse agonism to agonism, indicating the importance of this sequence. Introduction of β-(3-benzothienyl)-d-alanine (d-Bth), 3,3-diphenyl-d-alanine (d-Dip) and 1-naphthyl-d-alanine (d-1-Nal) at position 2 resulted in highly potent and efficient inverse agonists, whereas the substitution of d-tryptophane at position 4 with 1-naphthyl-d-alanine (d-1-Nal) and 2-naphthyl-d-alanine (d-2-Nal) induces agonism in functional assays. Competitive binding studies showed a high affinity of the inverse agonist K-(d-1-Nal)-FwLL-NH(2) at the ghrelin receptor. Moreover, mutagenesis studies of the receptor revealed key positions for the switch between inverse agonist and agonist response. Hence, only minor changes in the peptide sequence can decide between agonism and inverse agonism and have a major impact on the biological activity.
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Affiliation(s)
- Sylvia Els
- Institute of Biochemistry, Universität Leipzig, Brüderstraße 34, 04103 Leipzig, Germany
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43
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Wise H. The roles played by highly truncated splice variants of G protein-coupled receptors. J Mol Signal 2012; 7:13. [PMID: 22938630 PMCID: PMC3477067 DOI: 10.1186/1750-2187-7-13] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 07/29/2012] [Indexed: 01/08/2023] Open
Abstract
Alternative splicing of G protein-coupled receptor (GPCR) genes greatly increases the total number of receptor isoforms which may be expressed in a cell-dependent and time-dependent manner. This increased diversity of cell signaling options caused by the generation of splice variants is further enhanced by receptor dimerization. When alternative splicing generates highly truncated GPCRs with less than seven transmembrane (TM) domains, the predominant effect in vitro is that of a dominant-negative mutation associated with the retention of the wild-type receptor in the endoplasmic reticulum (ER). For constitutively active (agonist-independent) GPCRs, their attenuated expression on the cell surface, and consequent decreased basal activity due to the dominant-negative effect of truncated splice variants, has pathological consequences. Truncated splice variants may conversely offer protection from disease when expression of co-receptors for binding of infectious agents to cells is attenuated due to ER retention of the wild-type co-receptor. In this review, we will see that GPCRs retained in the ER can still be functionally active but also that highly truncated GPCRs may also be functionally active. Although rare, some truncated splice variants still bind ligand and activate cell signaling responses. More importantly, by forming heterodimers with full-length GPCRs, some truncated splice variants also provide opportunities to generate receptor complexes with unique pharmacological properties. So, instead of assuming that highly truncated GPCRs are associated with faulty transcription processes, it is time to reassess their potential benefit to the host organism.
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Affiliation(s)
- Helen Wise
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, China.
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Mokrosiński J, Frimurer TM, Sivertsen B, Schwartz TW, Holst B. Modulation of constitutive activity and signaling bias of the ghrelin receptor by conformational constraint in the second extracellular loop. J Biol Chem 2012; 287:33488-502. [PMID: 22846991 DOI: 10.1074/jbc.m112.383240] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Based on a rare, natural Glu for Ala-204(C+6) variant located six residues after the conserved Cys residue in extracellular loop 2b (ECL2b) associated with selective elimination of the high constitutive signaling of the ghrelin receptor, this loop was subjected to a detailed structure functional analysis. Introduction of Glu in different positions demonstrated that although the constitutive signaling was partly reduced when introduced in position 205(C+7) it was only totally eliminated in position 204(C+6). No charge-charge interaction partner could be identified for the Glu(C+6) variant despite mutational analysis of a number of potential partners in the extracellular loops and outer parts of the transmembrane segments. Systematic probing of position 204(C+6) with amino acid residues of different physicochemical properties indicated that a positively charged Lys surprisingly provided phenotypes similar to those of the negatively charged Glu residue. Computational chemistry analysis indicated that the propensity for the C-terminal segment of extracellular loop 2b to form an extended α-helix was increased from 15% in the wild type to 89 and 82% by introduction in position 204(C+6) of a Glu or a Lys residue, respectively. Moreover, the constitutive activity of the receptor was inhibited by Zn(2+) binding in an engineered metal ion site, stabilizing an α-helical conformation of this loop segment. It is concluded that the high constitutive activity of the ghrelin receptor is dependent upon flexibility in the C-terminal segment of extracellular loop 2 and that mutations or ligand binding that constrains this segment and thereby conceivably the movements of transmembrane domain V relative to transmembrane domain III inhibits the high constitutive signaling.
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Affiliation(s)
- Jacek Mokrosiński
- Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen N, Denmark
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45
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Kern A, Albarran-Zeckler R, Walsh HE, Smith RG. Apo-ghrelin receptor forms heteromers with DRD2 in hypothalamic neurons and is essential for anorexigenic effects of DRD2 agonism. Neuron 2012; 73:317-32. [PMID: 22284186 DOI: 10.1016/j.neuron.2011.10.038] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2011] [Indexed: 12/25/2022]
Abstract
We identified subsets of neurons in the brain that coexpress the dopamine receptor subtype-2 (DRD2) and the ghrelin receptor (GHSR1a). Combination of FRET confocal microscopy and Tr-FRET established the presence of GHSR1a:DRD2 heteromers in hypothalamic neurons. To interrogate function, mice were treated with the selective DRD2 agonist cabergoline, which produced anorexia in wild-type and ghrelin⁻/⁻ mice; intriguingly, ghsr⁻/⁻ mice were refractory illustrating dependence on GHSR1a, but not ghrelin. Elucidation of mechanism showed that formation of GHSR1a:DRD2 heteromers allosterically modifies canonical DRD2 dopamine signaling resulting in Gβγ subunit-dependent mobilization of [Ca²⁺](i) independent of GHSR1a basal activity. By targeting the interaction between GHSR1a and DRD2 in wild-type mice with a highly selective GHSR1a antagonist (JMV2959) cabergoline-induced anorexia was blocked. Inhibiting dopamine signaling in subsets of neurons with a GHSR1a antagonist has profound therapeutic implications by providing enhanced selectivity because neurons expressing DRD2 alone would be unaffected.
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Affiliation(s)
- Andras Kern
- Department of Metabolism and Aging, The Scripps Research Institute-Scripps Florida, Jupiter, FL 33458, USA
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46
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Identification of spirocyclic piperidine-azetidine inverse agonists of the ghrelin receptor. Bioorg Med Chem Lett 2012; 22:4281-7. [DOI: 10.1016/j.bmcl.2012.05.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 05/04/2012] [Accepted: 05/08/2012] [Indexed: 12/27/2022]
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47
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Rediger A, Piechowski CL, Habegger K, Grüters A, Krude H, Tschöp MH, Kleinau G, Biebermann H. MC4R dimerization in the paraventricular nucleus and GHSR/MC3R heterodimerization in the arcuate nucleus: is there relevance for body weight regulation? Neuroendocrinology 2012; 95:277-88. [PMID: 22327910 DOI: 10.1159/000334903] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 11/06/2011] [Indexed: 01/21/2023]
Abstract
The worldwide obesity epidemic is increasing, yet at this time, no long-acting and specific pharmaceutical therapies are available. Peripheral hormonal signals communicate metabolic status to the hypothalamus by activating their corresponding receptors in the arcuate nucleus (ARC). In this brain region, a variety of G protein-coupled receptors (GPCRs) are expressed that are potentially involved in weight regulation, but so far, the detailed function of most hypothalamic GPCRs is only partially understood. An important and underappreciated feature of GPCRs is the capacity for regulation via di- and heterodimerization. Increasing evidence implicates that heterodimerization of GPCRs results in profound functional consequences. Recently, we could demonstrate that interaction of the melanocortin 3 receptor (MC3R) and the growth hormone secretagogue receptor (GHSR)-1a results in a modulation of function in both receptors. Although the physiological role of GPCR-GPCR interaction in the hypothalamus is yet to be elucidated, this concept promises new avenues for investigation and understanding of hypothalamic functions dependent on GPCR signaling. Since GPCRs are important targets for drugs to combat many diseases, identification of heterodimers may be a prerequisite for highly specific drugs. Therefore, a detailed understanding of the mechanisms and their involvement in weight regulation is necessary. Fundamental to this understanding is the interplay of GPCR-GPCR in the hypothalamic nuclei in energy metabolism. In this review, we summarize the current knowledge on melanocortin receptors and GHSR-1a in hypothalamic weight regulation, especially as they pertain to possible drug targets. Furthermore, we include available evidence for the participation and significance of GPCR dimerization.
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MESH Headings
- Animals
- Appetite Regulation/physiology
- Arcuate Nucleus of Hypothalamus/anatomy & histology
- Arcuate Nucleus of Hypothalamus/metabolism
- Arcuate Nucleus of Hypothalamus/physiology
- Body Weight/physiology
- Humans
- Models, Biological
- Paraventricular Hypothalamic Nucleus/anatomy & histology
- Paraventricular Hypothalamic Nucleus/metabolism
- Paraventricular Hypothalamic Nucleus/physiology
- Protein Multimerization/physiology
- Receptor, Melanocortin, Type 3/metabolism
- Receptor, Melanocortin, Type 3/physiology
- Receptor, Melanocortin, Type 4/metabolism
- Receptor, Melanocortin, Type 4/physiology
- Receptors, Ghrelin/metabolism
- Receptors, Ghrelin/physiology
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Affiliation(s)
- Anne Rediger
- Institute of Experimental Pediatric Endocrinology, Charité Universitätsmedizin Berlin, Humboldt University, Berlin, Germany
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48
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Sivertsen B, Lang M, Frimurer TM, Holliday ND, Bach A, Els S, Engelstoft MS, Petersen PS, Madsen AN, Schwartz TW, Beck-Sickinger AG, Holst B. Unique interaction pattern for a functionally biased ghrelin receptor agonist. J Biol Chem 2011; 286:20845-60. [PMID: 21402696 DOI: 10.1074/jbc.m110.173237] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Based on the conformationally constrained D-Trp-Phe-D-Trp (wFw) core of the prototype inverse agonist [D-Arg(1),D-Phe(5),D-Trp(7,9),Leu(11)]substance P, a series of novel, small, peptide-mimetic agonists for the ghrelin receptor were generated. By using various simple, ring-constrained spacers connecting the D-Trp-Phe-D-Trp motif with the important C-terminal carboxyamide group, 40 nm agonism potency was obtained and also in one case (wFw-Isn-NH(2), where Isn is isonipecotic acid) ~80% efficacy. However, in contrast to all previously reported ghrelin receptor agonists, the piperidine-constrained wFw-Isn-NH(2) was found to be a functionally biased agonist. Thus, wFw-Isn-NH(2) mediated potent and efficacious signaling through the Gα(q) and ERK1/2 signaling pathways, but in contrast to all previous ghrelin receptor agonists it did not signal through the serum response element, conceivably the Gα(12/13) pathway. The recognition pattern of wFw-Isn-NH(2) with the ghrelin receptor also differed significantly from that of all previously characterized unbiased agonists. Most importantly, wFw-Isn-NH(2) was not dependent on GluIII:09 (Glu3.33), which otherwise is an obligatory TM III anchor point residue for ghrelin agonists. Molecular modeling and docking experiments indicated that wFw-Isn-NH(2) binds in the classical agonist binding site between the extracellular segments of TMs III, VI, and VII, interacting closely with the aromatic cluster between TMs VI and VII, but that it does so in an opposite orientation as compared with, for example, the wFw peptide agonists. It is concluded that the novel peptide-mimetic ligand wFw-Isn-NH(2) is a biased ghrelin receptor agonist and that the selective signaling pattern presumably is due to its unique receptor recognition pattern lacking interaction with key residues especially in TM III.
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Affiliation(s)
- Bjørn Sivertsen
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3b, DK-2200, Copenhagen, Denmark
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Tschammer N, Bollinger S, Kenakin T, Gmeiner P. Histidine 6.55 is a major determinant of ligand-biased signaling in dopamine D2L receptor. Mol Pharmacol 2010; 79:575-85. [PMID: 21163968 DOI: 10.1124/mol.110.068106] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In our previous studies, we demonstrated that the mutation of His393(6.55) to alanine results in an increased affinity of 1,4-disubstituted phenylpiperazines to the dopamine D(2L) receptor. This change most likely accounts for the reduced steric hindrance in this part of the binding pocket. In this work, we investigated the role of the steric hindrance imposed by the residue His393(6.55) for the receptor activation modulated by 1,4-disubstituted aromatic piperidines/piperazines. Site-directed mutagenesis and ligand modifications were used to probe the structural basis of ligand efficacy. The operational model of agonism was used to quantify the ligand bias between the ability of compounds to inhibit cAMP accumulation and stimulate extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation. Whereas substantial ligand-biased signaling was observed for the D(2L) wild-type receptor, an overall increase in agonism was observed for the D(2L) H393(6.55)A mutant without noteworthy functional selectivity. Targeted chemical modification of the phenylpiperazine moiety at the site of its interaction with the residue His393(6.55) led to the functionally selective ligand {3-[4-(2,3-dihydro-benzofuran-7-yl)-piperazin-1-yl]-propyl}-pyrazol[1,5-a]pyridine-3-carboxamide (FAUC350) that has distinct signaling profiles toward adenylyl cyclase and ERK1/2. FAUC350 behaves as an antagonist in the inhibition of cAMP accumulation and as a partial agonist in the stimulation of ERK1/2 phosphorylation (efficacy = 55%). Overall, the residue His393(6.55) and proximate molecular substructures of receptor ligands were identified to be crucial for multidimensional ligand efficacy.
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Affiliation(s)
- Nuska Tschammer
- Department of Chemistry and Pharmacy, Friedrich Alexander University, Erlangen, Germany
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50
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Staes E, Absil PA, Lins L, Brasseur R, Deleu M, Lecouturier N, Fievez V, Rieux AD, Mingeot-Leclercq MP, Raussens V, Préat V. Acylated and unacylated ghrelin binding to membranes and to ghrelin receptor: towards a better understanding of the underlying mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:2102-13. [PMID: 20637180 DOI: 10.1016/j.bbamem.2010.07.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 07/02/2010] [Accepted: 07/06/2010] [Indexed: 10/19/2022]
Abstract
The O-octanoylation of human ghrelin is a natural post-translational modification that enhances its binding to model membranes and could potentially play a central role in ghrelin biological activities. Here, we aimed to clarify the mechanisms that drive ghrelin to the membrane and hence to its receptor that mediates most of its endocrinological effects. As the acylation enhances ghrelin lipophilicity and that ghrelin contains many basic residues, we examined the electrostatic attraction and/or hydrophobic interactions with membranes. Using various liposomes and buffer conditions in binding, zeta potential and isothermal titration calorimetry studies, we found that whereas acylated and unacylated ghrelin were both electrostatically attracted towards the membrane, only acylated ghrelin penetrated into the headgroup and the lipid backbone regions of negatively charged membranes. The O-acylation induced a 120-fold increase in ghrelin local concentration in the membrane. However, acylated ghrelin did not deeply penetrate the membrane nor did it perturb its organisation. Conformational studies by circular dichroism and attenuated total reflection Fourier transformed infrared as well as in silico modelling revealed that both forms of ghrelin mainly adopted the same structure in aqueous, micellar and bilayer environments even though acylated ghrelin structure is slightly more α-helical in a lipid bilayer environment. Altogether our results suggest that membrane acts as a "catalyst" in acylated ghrelin binding to the ghrelin receptor and hence could explain why acylated and unacylated ghrelin are both full agonists of this receptor but in the nanomolar and micromolar range, respectively.
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Affiliation(s)
- Edith Staes
- Université catholique de Louvain, Unité de Pharmacie Galénique, 1200 Brussels, Belgium.
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