1
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Aksu H, Demirbilek A, Uba AI. Insights into the structure and activation mechanism of some class B1 GPCR family members. Mol Biol Rep 2024; 51:966. [PMID: 39240462 DOI: 10.1007/s11033-024-09876-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 08/20/2024] [Indexed: 09/07/2024]
Abstract
In humans, 15 genes encode the class B1 family of GPCRs, which are polypeptide hormone receptors characterized by having a large N-terminal extracellular domain (ECD) and receive signals from outside the cell to activate cellular response. For example, the insulinotropic polypeptide (GIP) stimulates the glucose-dependent insulinotropic polypeptide receptor (GIPR), while the glucagon receptor (GCGR) responds to glucagon by increasing blood glucose levels and promoting the breakdown of liver glycogen to induce the production of insulin. The glucagon-like peptides 1 and 2 (GLP-1 and GLP-2) elicit a response from glucagon-like peptide receptor types 1 and 2 (GLP1R and GLP2R), respectively. Since these receptors are implicated in the pathogenesis of diabetes, studying their activation is crucial for the development of effective therapies for the condition. With more structural information being revealed by experimental methods such as X-ray crystallography, cryo-EM, and NMR, the activation mechanism of class B1 GPCRs becomes unraveled. The available crystal and cryo-EM structures reveal that class B1 GPCRs follow a two-step model for peptide binding and receptor activation. The regions close to the C-termini of hormones interact with the N-terminal ECD of the receptor while the regions close to the N-terminus of the peptide interact with the TM domain and transmit signals. This review highlights the structural details of class B1 GPCRs and their conformational changes following activation. The roles of MD simulation in characterizing those conformational changes are briefly discussed, providing insights into the potential structural exploration for future ligand designs.
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MESH Headings
- Humans
- Receptors, G-Protein-Coupled/metabolism
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/genetics
- Crystallography, X-Ray/methods
- Protein Conformation
- Animals
- Glucagon-Like Peptide-1 Receptor/metabolism
- Glucagon-Like Peptide-1 Receptor/genetics
- Receptors, Gastrointestinal Hormone/metabolism
- Receptors, Gastrointestinal Hormone/chemistry
- Receptors, Gastrointestinal Hormone/genetics
- Glucagon-Like Peptide 1/metabolism
- Models, Molecular
- Protein Binding
- Signal Transduction
- Receptors, Glucagon/metabolism
- Receptors, Glucagon/genetics
- Receptors, Glucagon/chemistry
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Affiliation(s)
- Hayrunisa Aksu
- Department of Molecular Biology and Genetics, Istanbul AREL University, Istanbul, 34537, Turkey
| | - Ayşenur Demirbilek
- Department of Molecular Biology and Genetics, Istanbul AREL University, Istanbul, 34537, Turkey
| | - Abdullahi Ibrahim Uba
- Department of Molecular Biology and Genetics, Istanbul AREL University, Istanbul, 34537, Turkey.
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2
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Meschi E, Duquenoy L, Otto N, Dempsey G, Waddell S. Compensatory enhancement of input maintains aversive dopaminergic reinforcement in hungry Drosophila. Neuron 2024; 112:2315-2332.e8. [PMID: 38795709 DOI: 10.1016/j.neuron.2024.04.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 03/12/2024] [Accepted: 04/30/2024] [Indexed: 05/28/2024]
Abstract
Hungry animals need compensatory mechanisms to maintain flexible brain function, while modulation reconfigures circuits to prioritize resource seeking. In Drosophila, hunger inhibits aversively reinforcing dopaminergic neurons (DANs) to permit the expression of food-seeking memories. Multitasking the reinforcement system for motivation potentially undermines aversive learning. We find that chronic hunger mildly enhances aversive learning and that satiated-baseline and hunger-enhanced learning require endocrine adipokinetic hormone (AKH) signaling. Circulating AKH influences aversive learning via its receptor in four neurons in the ventral brain, two of which are octopaminergic. Connectomics revealed AKH receptor-expressing neurons to be upstream of several classes of ascending neurons, many of which are presynaptic to aversively reinforcing DANs. Octopaminergic modulation of and output from at least one of these ascending pathways is required for shock- and bitter-taste-reinforced aversive learning. We propose that coordinated enhancement of input compensates for hunger-directed inhibition of aversive DANs to preserve reinforcement when required.
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Affiliation(s)
- Eleonora Meschi
- University of Oxford, Centre for Neural Circuits and Behaviour, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Lucille Duquenoy
- University of Oxford, Centre for Neural Circuits and Behaviour, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Nils Otto
- University of Oxford, Centre for Neural Circuits and Behaviour, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Georgia Dempsey
- University of Oxford, Centre for Neural Circuits and Behaviour, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Scott Waddell
- University of Oxford, Centre for Neural Circuits and Behaviour, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK.
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3
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Li M, Zhang X, Li S, Guo J. Unraveling the Interplay of Extracellular Domain Conformational Changes and Parathyroid Hormone Type 1 Receptor Activation in Class B1 G Protein-Coupled Receptors: Integrating Enhanced Sampling Molecular Dynamics Simulations and Markov State Models. ACS Chem Neurosci 2024; 15:844-853. [PMID: 38314550 DOI: 10.1021/acschemneuro.3c00747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2024] Open
Abstract
Parathyroid hormone (PTH) type 1 receptor (PTH1R), as a typical class B1 G protein-coupled receptor (GPCR), is responsible for regulating bone turnover and maintaining calcium homeostasis, and its dysregulation has been implicated in the development of several diseases. The extracellular domain (ECD) of PTH1R is crucial for the recognition and binding of ligands, and the receptor may exhibit an autoinhibited state with the closure of the ECD in the absence of ligands. However, the correlation between ECD conformations and PTH1R activation remains unclear. Thus, this study combines enhanced sampling molecular dynamics (MD) simulations and Markov state models (MSMs) to reveal the possible relevance between the ECD conformations and the activation of PTH1R. First, 22 intermediate structures are generated from the autoinhibited state to the active state and conducted for 10 independent 200 ns simulations each. Then, the MSM is constructed based on the cumulative 44 μs simulations with six identified microstates. Finally, the potential interplay between ECD conformational changes and PTH1R activation as well as cryptic allosteric pockets in the intermediate states during receptor activation is revealed. Overall, our findings reveal that the activation of PTH1R has a specific correlation with ECD conformational changes and provide essential insights for GPCR biology and developing novel allosteric modulators targeting cryptic sites.
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Affiliation(s)
- Mengrong Li
- School of Physics and Astronomy & Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiaoxiao Zhang
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Shu Li
- Centre in Artificial Intelligence Driven Drug Discovery, Faculty of Applied Sciences, Macao Polytechnic University, Macao 999078, China
| | - Jingjing Guo
- Centre in Artificial Intelligence Driven Drug Discovery, Faculty of Applied Sciences, Macao Polytechnic University, Macao 999078, China
- Engineering Research Centre of Applied Technology on Machine Translation and Artificial Intelligence, Macao Polytechnic University, Macao 999078, China
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4
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Allard C, Cota D, Quarta C. Poly-Agonist Pharmacotherapies for Metabolic Diseases: Hopes and New Challenges. Drugs 2024; 84:127-148. [PMID: 38127286 DOI: 10.1007/s40265-023-01982-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2023] [Indexed: 12/23/2023]
Abstract
The use of glucagon-like peptide-1 (GLP-1) receptor-based multi-agonists in the treatment of type 2 diabetes and obesity holds great promise for improving glycaemic control and weight management. Unimolecular dual and triple agonists targeting multiple gut hormone-related pathways are currently in clinical trials, with recent evidence supporting their efficacy. However, significant knowledge gaps remain regarding the biological mechanisms and potential adverse effects associated with these multi-target agents. The mechanisms underlying the therapeutic efficacy of GLP-1 receptor-based multi-agonists remain somewhat mysterious, and hidden threats may be associated with the use of gut hormone-based polyagonists. In this review, we provide a critical analysis of the benefits and risks associated with the use of these new drugs in the management of obesity and diabetes, while also exploring new potential applications of GLP-1-based pharmacology beyond the field of metabolic disease.
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Affiliation(s)
- Camille Allard
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, 33000, Bordeaux, France
| | - Daniela Cota
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, 33000, Bordeaux, France
| | - Carmelo Quarta
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, 33000, Bordeaux, France.
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5
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Novikoff A, Müller TD. The molecular pharmacology of glucagon agonists in diabetes and obesity. Peptides 2023; 165:171003. [PMID: 36997003 PMCID: PMC10265134 DOI: 10.1016/j.peptides.2023.171003] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 03/31/2023]
Abstract
Within recent decades glucagon receptor (GcgR) agonism has drawn attention as a therapeutic tool for the treatment of type 2 diabetes and obesity. In both mice and humans, glucagon administration enhances energy expenditure and suppresses food intake suggesting a promising metabolic utility. Therefore synthetic optimization of glucagon-based pharmacology to further resolve the physiological and cellular underpinnings mediating these effects has advanced. Chemical modifications to the glucagon sequence have allowed for greater peptide solubility, stability, circulating half-life, and understanding of the structure-function potential behind partial and "super"-agonists. The knowledge gained from such modifications has provided a basis for the development of long-acting glucagon analogues, chimeric unimolecular dual- and tri-agonists, and novel strategies for nuclear hormone targeting into glucagon receptor-expressing tissues. In this review, we summarize the developments leading toward the current advanced state of glucagon-based pharmacology, while highlighting the associated biological and therapeutic effects in the context of diabetes and obesity.
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Affiliation(s)
- Aaron Novikoff
- Institute of Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany.
| | - Timo D Müller
- Institute of Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany.
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6
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Duffet L, Williams ET, Gresch A, Chen S, Bhat MA, Benke D, Hartrampf N, Patriarchi T. Optical tools for visualizing and controlling human GLP-1 receptor activation with high spatiotemporal resolution. eLife 2023; 12:86628. [PMID: 37265064 DOI: 10.7554/elife.86628] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023] Open
Abstract
The glucagon-like peptide-1 receptor (GLP1R) is a broadly expressed target of peptide hormones with essential roles in energy and glucose homeostasis, as well as of the blockbuster weight-loss drugs semaglutide and liraglutide. Despite its large clinical relevance, tools to investigate the precise activation dynamics of this receptor with high spatiotemporal resolution are limited. Here, we introduce a novel genetically encoded sensor based on the engineering of a circularly permuted green fluorescent protein into the human GLP1R, named GLPLight1. We demonstrate that fluorescence signal from GLPLight1 accurately reports the expected receptor conformational activation in response to pharmacological ligands with high sensitivity (max ΔF/F0=528%) and temporal resolution (τON = 4.7 s). We further demonstrated that GLPLight1 shows comparable responses to glucagon-like peptide-1 (GLP-1) derivatives as observed for the native receptor. Using GLPLight1, we established an all-optical assay to characterize a novel photocaged GLP-1 derivative (photo-GLP1) and to demonstrate optical control of GLP1R activation. Thus, the new all-optical toolkit introduced here enhances our ability to study GLP1R activation with high spatiotemporal resolution.
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Affiliation(s)
- Loïc Duffet
- Institute of Pharmacology and Toxicology, University of Zürich, Zurich, Switzerland
| | - Elyse T Williams
- Department of Chemistry, University of Zürich, Zürich, Switzerland
| | - Andrea Gresch
- Institute of Pharmacology and Toxicology, University of Zürich, Zurich, Switzerland
| | - Simin Chen
- Department of Chemistry, University of Zürich, Zürich, Switzerland
| | - Musadiq A Bhat
- Institute of Pharmacology and Toxicology, University of Zürich, Zurich, Switzerland
| | - Dietmar Benke
- Institute of Pharmacology and Toxicology, University of Zürich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zürich, Zürich, Switzerland
| | - Nina Hartrampf
- Department of Chemistry, University of Zürich, Zürich, Switzerland
| | - Tommaso Patriarchi
- Institute of Pharmacology and Toxicology, University of Zürich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zürich, Zürich, Switzerland
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7
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Edgerton DS, Kraft G, Smith M, Farmer B, Williams P, Cherrington AD. A physiologic increase in brain glucagon action alters the hepatic gluconeogenic/glycogenolytic ratio but not glucagon's overall effect on glucose production. Am J Physiol Endocrinol Metab 2023; 324:E199-E208. [PMID: 36652399 PMCID: PMC9925168 DOI: 10.1152/ajpendo.00304.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/12/2023] [Accepted: 01/12/2023] [Indexed: 01/19/2023]
Abstract
It has been proposed that brain glucagon action inhibits glucagon-stimulated hepatic glucose production (HGP), which may explain, at least in part, why glucagon's effect on HGP is transient. However, the pharmacologic off-target effects of glucagon in the brain may have been responsible for previously observed effects. Therefore, the aim of this study was to determine if central glucagon action plays a physiologic role in the regulation of HGP. Insulin was maintained at baseline while glucagon was either infused into the carotid and vertebral arteries or into a peripheral (leg) vein at rates designed to increase glucagon in the head in one group, while keeping glucagon at the liver matched between groups. The extraction rate of glucagon across the head was high (double that of the liver), and hypothalamic cAMP increased twofold, in proportion to the exposure of the brain to increased glucagon, but HGP was not reduced by the increase in brain glucagon signaling, as had been suggested previously (the areas under the curve for HGP were 840 ± 14 vs. 871 ± 36 mg/kg/240 min in head vs. peripheral infusion groups, respectively). Central nervous system glucagon action reduced circulating free fatty acids and glycerol, and this was associated with a modest reduction in net hepatic gluconeogenic flux. However, offsetting autoregulation by the liver (i.e., a reciprocal increase in net hepatic glycogenolysis) prevented a change in HGP. Thus, while physiologic engagement of the brain by glucagon can alter hepatic carbon flux, it does not appear to be responsible for the transient fall in HGP that occurs following the stimulation of HGP during a square wave rise in glucagon.NEW & NOTEWORTHY Glucagon stimulates hepatic glucose production through its direct effects on the liver but may indirectly inhibit this process by acting on the brain. This was tested by delivering glucagon via the cerebral circulatory system. Central nervous system glucagon action reduced liver gluconeogenic flux, but glycogenolysis increased, resulting in no net change in hepatic glucose production. Surprisingly, brain glucagon also appeared to suppress lipolysis (plasma free fatty acid and glycerol levels were reduced).
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Affiliation(s)
- Dale S Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Marta Smith
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Phillip Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
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8
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Rodgers RL. A reappraisal of the role of cyclic AMP in the physiological action of glucagon. Peptides 2023; 159:170906. [PMID: 36396082 DOI: 10.1016/j.peptides.2022.170906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 11/11/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022]
Abstract
Effects of the metabolic hormone glucagon can be physiological or supraphysiological, based on agonist concentration and the mediating cellular signal. The threshold concentration (TC) for activating the AC/cAMP signal pathway in liver is ≥ 100 pM. By contrast, mean plasma concentrations are around 20-45 pM, depending on the vascular bed. Accordingly, effects produced at TCs below 100 pM are physiological and mediated by cellular signal pathways other than AC/cAMP. Effects generated at concentrations above 100 pM are supraphysiological, often mediated by simultaneous activation of cAMP-independent and -dependent pathways. Physiological responses, and their established or implicated signal pathways, include stimulation of: glucose mobilization, fatty acid oxidation, and urea synthesis in liver (PLC/IP3/Ca2+/CaM); lipolysis in white and brown adipose tissue and oxygen consumption in brown adipose of the rat but not in humans (PLC/IP3/Ca2+/CaM); renal potassium and phosphate excretion in rodents and GFR in humans (signal undetermined); and glucose utilization in rat heart (PI3K/akt). Supraphysiological responses involve the AC/cAMP pathway and include: enhanced stimulation of glucose mobilization and stimulation of urea synthesis in liver; further stimulation of white and brown adipose lipolysis and thermogenesis in brown adipose tissue; stimulation of renal Cl- transport; and increased rat heart contractility. The AC/cAMP pathway is likely recruited when plasma glucagon rises above 100 pM during periods of elevated metabolic stress and systemic glucose demand, such as in the early neonate or strenuously exercising adult. The current cAMP-centered model should therefore be reconsidered and replaced with one that places more emphasis on cAMP-independent pathways.
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Affiliation(s)
- Robert L Rodgers
- Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02935, USA.
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9
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Cary BP, Zhang X, Cao J, Johnson RM, Piper SJ, Gerrard EJ, Wootten D, Sexton PM. New insights into the structure and function of class B1 GPCRs. Endocr Rev 2022; 44:492-517. [PMID: 36546772 PMCID: PMC10166269 DOI: 10.1210/endrev/bnac033] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 11/07/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022]
Abstract
G protein-coupled receptors (GPCRs) are the largest family of cell surface receptors. Class B1 GPCRs constitute a subfamily of 15 receptors that characteristically contain large extracellular domains (ECDs) and respond to long polypeptide hormones. Class B1 GPCRs are critical regulators of homeostasis, and as such, many are important drug targets. While most transmembrane proteins, including GPCRs, are recalcitrant to crystallization, recent advances in electron cryo-microscopy (cryo-EM) have facilitated a rapid expansion of the structural understanding of membrane proteins. As a testament to this success, structures for all the class B1 receptors bound to G proteins have been determined by cryo-EM in the past five years. Further advances in cryo-EM have uncovered dynamics of these receptors, ligands, and signalling partners. Here, we examine the recent structural underpinnings of the class B1 GPCRs with an emphasis on structure-function relationships.
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Affiliation(s)
- Brian P Cary
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia.,ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Xin Zhang
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia.,ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Jianjun Cao
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia.,ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Rachel M Johnson
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia.,ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Sarah J Piper
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia.,ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Elliot J Gerrard
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia.,ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Denise Wootten
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia.,ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Patrick M Sexton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia.,ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
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10
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Insights into the Role of Glucagon Receptor Signaling in Metabolic Regulation from Pharmacological Inhibition and Tissue-Specific Knockout Models. Biomedicines 2022; 10:biomedicines10081907. [PMID: 36009454 PMCID: PMC9405517 DOI: 10.3390/biomedicines10081907] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/01/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022] Open
Abstract
While glucagon has long been recognized as the primary counter hormone to insulin’s actions, it has recently gained recognition as a metabolic regulator with its effects extending beyond control of glycemia. Recently developed models of tissue-specific glucagon receptor knockouts have advanced our understanding of this hormone, providing novel insight into the role it plays within organs as well as its systemic effects. Studies where the pharmacological blockade of the glucagon receptor has been employed have proved similarly valuable in the study of organ-specific and systemic roles of glucagon signaling. Studies carried out employing these tools demonstrate that glucagon indeed plays a role in regulating glycemia, but also in amino acid and lipid metabolism, systemic endocrine, and paracrine function, and in the response to cardiovascular injury. Here, we briefly review recent progress in our understanding of glucagon’s role made through inhibition of glucagon receptor signaling utilizing glucagon receptor antagonists and tissue specific genetic knockout models.
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11
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Franklin ZJ, Lafferty RA, Flatt PR, McShane LM, O'Harte FP, Irwin N. Metabolic effects of combined glucagon receptor antagonism and glucagon-like peptide-1 receptor agonism in high fat fed mice. Biochimie 2022; 199:60-67. [DOI: 10.1016/j.biochi.2022.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/05/2022] [Accepted: 04/13/2022] [Indexed: 01/19/2023]
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12
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Asadi F, Dhanvantari S. Pathways of Glucagon Secretion and Trafficking in the Pancreatic Alpha Cell: Novel Pathways, Proteins, and Targets for Hyperglucagonemia. Front Endocrinol (Lausanne) 2021; 12:726368. [PMID: 34659118 PMCID: PMC8511682 DOI: 10.3389/fendo.2021.726368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 09/13/2021] [Indexed: 12/15/2022] Open
Abstract
Patients with diabetes mellitus exhibit hyperglucagonemia, or excess glucagon secretion, which may be the underlying cause of the hyperglycemia of diabetes. Defective alpha cell secretory responses to glucose and paracrine effectors in both Type 1 and Type 2 diabetes may drive the development of hyperglucagonemia. Therefore, uncovering the mechanisms that regulate glucagon secretion from the pancreatic alpha cell is critical for developing improved treatments for diabetes. In this review, we focus on aspects of alpha cell biology for possible mechanisms for alpha cell dysfunction in diabetes: proglucagon processing, intrinsic and paracrine control of glucagon secretion, secretory granule dynamics, and alterations in intracellular trafficking. We explore possible clues gleaned from these studies in how inhibition of glucagon secretion can be targeted as a treatment for diabetes mellitus.
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Affiliation(s)
- Farzad Asadi
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
- Program in Metabolism and Diabetes, Lawson Health Research Institute, London, ON, Canada
| | - Savita Dhanvantari
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
- Program in Metabolism and Diabetes, Lawson Health Research Institute, London, ON, Canada
- Imaging Research Program, Lawson Health Research Institute, London, ON, Canada
- Department of Medical Biophysics, Western University, London, ON, Canada
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13
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Galvin SG, Kay RG, Foreman R, Larraufie P, Meek CL, Biggs E, Ravn P, Jermutus L, Reimann F, Gribble FM. The Human and Mouse Islet Peptidome: Effects of Obesity and Type 2 Diabetes, and Assessment of Intraislet Production of Glucagon-like Peptide-1. J Proteome Res 2021; 20:4507-4517. [PMID: 34423991 PMCID: PMC8419866 DOI: 10.1021/acs.jproteome.1c00463] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Indexed: 02/07/2023]
Abstract
To characterize the impact of metabolic disease on the peptidome of human and mouse pancreatic islets, LC-MS was used to analyze extracts of human and mouse islets, purified mouse alpha, beta, and delta cells, supernatants from mouse islet incubations, and plasma from patients with type 2 diabetes. Islets were obtained from healthy and type 2 diabetic human donors, and mice on chow or high fat diet. All major islet hormones were detected in lysed islets as well as numerous peptides from vesicular proteins including granins and processing enzymes. Glucose-dependent insulinotropic peptide (GIP) was not detectable. High fat diet modestly increased islet content of proinsulin-derived peptides in mice. Human diabetic islets contained increased content of proglucagon-derived peptides at the expense of insulin, but no evident prohormone processing defects. Diabetic plasma, however, contained increased ratios of proinsulin and des-31,32-proinsulin to insulin. Active GLP-1 was detectable in human and mouse islets but 100-1000-fold less abundant than glucagon. LC-MS offers advantages over antibody-based approaches for identifying exact peptide sequences, and revealed a shift toward islet insulin production in high fat fed mice, and toward proglucagon production in type 2 diabetes, with no evidence of systematic defective prohormone processing.
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Affiliation(s)
- Sam G. Galvin
- University
of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, Addenbrooke’s
Hospital, Hills Road, Cambridge, CB2 0QQ, U.K.
| | - Richard G. Kay
- University
of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, Addenbrooke’s
Hospital, Hills Road, Cambridge, CB2 0QQ, U.K.
| | - Rachel Foreman
- University
of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, Addenbrooke’s
Hospital, Hills Road, Cambridge, CB2 0QQ, U.K.
| | - Pierre Larraufie
- University
of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, Addenbrooke’s
Hospital, Hills Road, Cambridge, CB2 0QQ, U.K.
| | - Claire L. Meek
- University
of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, Addenbrooke’s
Hospital, Hills Road, Cambridge, CB2 0QQ, U.K.
| | - Emma Biggs
- University
of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, Addenbrooke’s
Hospital, Hills Road, Cambridge, CB2 0QQ, U.K.
| | - Peter Ravn
- Research
and Early Development Cardiovascular, Renal and Metabolism (CVRM),
BioPharmaceuticals R&D, AstraZeneca
Ltd., Cambridge, CB21 6GH, U.K.
| | - Lutz Jermutus
- Research
and Early Development Cardiovascular, Renal and Metabolism (CVRM),
BioPharmaceuticals R&D, AstraZeneca
Ltd., Cambridge, CB21 6GH, U.K.
| | - Frank Reimann
- University
of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, Addenbrooke’s
Hospital, Hills Road, Cambridge, CB2 0QQ, U.K.
| | - Fiona M. Gribble
- University
of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, Addenbrooke’s
Hospital, Hills Road, Cambridge, CB2 0QQ, U.K.
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14
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Abstract
Glucagon-Like Peptide-1 (GLP-1) is an important peptide hormone secreted by L-cells in the gastrointestinal tract in response to nutrients. It is produced by the differential cleavage of the proglucagon peptide. GLP-1 elicits a wide variety of physiological responses in many tissues that contribute to metabolic homeostasis. For these reasons, therapies designed to either increase endogenous GLP-1 levels or introduce exogenous peptide mimetics are now widely used in the management of diabetes. In addition to GLP-1 production from L-cells, recent reports suggest that pancreatic islet alpha cells may also synthesize and secrete GLP-1. Intra-islet GLP-1 may therefore play an unappreciated role in islet health and glucose regulation, suggesting a potential functional paracrine role for islet-derived GLP-1. In this review, we assess the current literature from an islet-centric point-of-view to better understand the production, degradation, and actions of GLP-1 within the endocrine pancreas in rodents and humans. The relevance of intra-islet GLP-1 in human physiology is discussed regarding the potential role of intra-islet GLP-1 in islet health and dysfunction.
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Affiliation(s)
- Scott A. Campbell
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montreal Diabetes Research Centre CRCHUM, Montréal, Canada
| | - Janyne Johnson
- Alberta Diabetes Institute, Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Peter E. Light
- Alberta Diabetes Institute, Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- CONTACT Peter E. Light Alberta Diabetes Institute, Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AlbertaT6G 2E1, Canada
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15
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Ahrén B, Yamada Y, Seino Y. The mediation by GLP-1 receptors of glucagon-induced insulin secretion revisited in GLP-1 receptor knockout mice. Peptides 2021; 135:170434. [PMID: 33172827 DOI: 10.1016/j.peptides.2020.170434] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/20/2020] [Accepted: 10/20/2020] [Indexed: 12/28/2022]
Abstract
To study whether activation of GLP-1 receptors importantly contributes to the insulinotropic action of exogenously administered glucagon, we have performed whole animal experiments in normal mice and in mice with GLP-1 receptor knockout. Glucagon (1, 3 or 10 μg/kg), the GLP-1 receptor antagonist exendin 9-39 (30 nmol/kg), glucose (0.35 g/kg) or the incretin hormone glucose-dependent insulinotropic polypeptide (GIP; 3 nmol/kg) was injected intravenously or glucose (75 mg) was given orally through gavage. Furthermore, islets were isolated and incubated in the presence of glucose with or without glucagon. It was found that the insulin response to intravenous glucagon was preserved in GLP-1 receptor knockout mice but that glucagon-induced insulin secretion was markedly suppressed in islets from GLP-1 receptor knockout mice. Similarly, the GLP-1 receptor antagonist markedly suppressed glucagon-induced insulin secretion in wildtype mice. These data suggest that GLP-1 receptors contribute to the insulinotropic action of glucagon and that there is a compensatory mechanism in GLP-1 receptor knockout mice that counteracts a reduced effect of glucagon. Two potential compensatory mechanisms (glucose and GIP) were explored. However, neither of these seemed to explain why the insulin response to glucagon is not suppressed in GLP-1 receptor knockout mice. Based on these data we confirm the hypothesis that glucagon-induced insulin secretion is partially mediated by GLP-1 receptors on the beta cells and we propose that a compensatory mechanism, the nature of which remains to be established, is induced in GLP-1 receptor knockout mice to counteract the expected impaired insulin response to glucagon in these mice.
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Affiliation(s)
- Bo Ahrén
- Department of Clinical Sciences Lund, Lund University, C11 BMC, Sölvegatan 19, 221 84 Lund, Sweden.
| | - Yuichiro Yamada
- Department of Endocrinology, Diabetes and Geriatric Medicine, Graduate School of Medicine, Akita University, Akita, Japan
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16
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Petersen KM, Bøgevig S, Riis T, Andersson NW, Dalhoff KP, Holst JJ, Knop FK, Faber J, Petersen TS, Christensen MB. High-Dose Glucagon Has Hemodynamic Effects Regardless of Cardiac Beta-Adrenoceptor Blockade: A Randomized Clinical Trial. J Am Heart Assoc 2020; 9:e016828. [PMID: 33103603 PMCID: PMC7763418 DOI: 10.1161/jaha.120.016828] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Background Intravenous high-dose glucagon is a recommended antidote against beta-blocker poisonings, but clinical effects are unclear. We therefore investigated hemodynamic effects and safety of high-dose glucagon with and without concomitant beta-blockade. Methods and Results In a randomized crossover study, 10 healthy men received combinations of esmolol (1.25 mg/kg bolus+0.75 mg/kg/min infusion), glucagon (50 µg/kg), and identical volumes of saline placebo on 5 separate days in random order (saline+saline; esmolol+saline; esmolol+glucagon bolus; saline+glucagon infusion; saline+glucagon bolus). On individual days, esmolol/saline was infused from -15 to 30 minutes. Glucagon/saline was administered from 0 minutes as a 2-minute intravenous bolus or as a 30-minute infusion (same total glucagon dose). End points were hemodynamic and adverse effects of glucagon compared with saline. Compared with saline, glucagon bolus increased mean heart rate by 13.0 beats per minute (95% CI, 8.0-18.0; P<0.001), systolic blood pressure by 15.6 mm Hg (95% CI, 8.0-23.2; P=0.002), diastolic blood pressure by 9.4 mm Hg (95% CI, 6.3-12.6; P<0.001), and cardiac output by 18.0 % (95% CI, 9.7-26.9; P=0.003) at the 5-minute time point on days without beta-blockade. Similar effects of glucagon bolus occurred on days with beta-blockade and between 15 and 30 minutes during infusion. Hemodynamic effects of glucagon thus reflected pharmacologic glucagon plasma concentrations. Glucagon-induced nausea occurred in 80% of participants despite ondansetron pretreatment. Conclusions High-dose glucagon boluses had significant hemodynamic effects regardless of beta-blockade. A glucagon infusion had comparable and apparently longer-lasting effects compared with bolus, indicating that infusion may be preferable to bolus injections. Registration Information URL: https://www.clinicaltrials.gov; Unique identifier: NCT03533179.
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Affiliation(s)
- Kasper M Petersen
- Department of Clinical Pharmacology Bispebjerg Hospital University of Copenhagen Copenhagen Denmark
| | - Søren Bøgevig
- Department of Clinical Pharmacology Bispebjerg Hospital University of Copenhagen Copenhagen Denmark
| | - Troels Riis
- Department of Clinical Pharmacology Bispebjerg Hospital University of Copenhagen Copenhagen Denmark
| | - Niklas W Andersson
- Department of Clinical Pharmacology Bispebjerg Hospital University of Copenhagen Copenhagen Denmark
| | - Kim P Dalhoff
- Department of Clinical Pharmacology Bispebjerg Hospital University of Copenhagen Copenhagen Denmark.,Department of Clinical Medicine Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Jens J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark.,Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Filip K Knop
- Novo Nordisk Foundation Center for Basic Metabolic Research Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark.,Department of Clinical Medicine Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark.,Center for Clinical Metabolic Research Gentofte HospitalUniversity of Copenhagen Hellerup Denmark.,Steno Diabetes Center Copenhagen Gentofte Denmark
| | - Jens Faber
- Department of Medicine Herlev HospitalUniversity of Copenhagen Copenhagen Denmark
| | - Tonny S Petersen
- Department of Clinical Pharmacology Bispebjerg Hospital University of Copenhagen Copenhagen Denmark.,Department of Clinical Medicine Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Mikkel B Christensen
- Department of Clinical Pharmacology Bispebjerg Hospital University of Copenhagen Copenhagen Denmark.,Department of Clinical Medicine Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark.,Center for Clinical Metabolic Research Gentofte HospitalUniversity of Copenhagen Hellerup Denmark
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17
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Campbell SA, Golec DP, Hubert M, Johnson J, Salamon N, Barr A, MacDonald PE, Philippaert K, Light PE. Human islets contain a subpopulation of glucagon-like peptide-1 secreting α cells that is increased in type 2 diabetes. Mol Metab 2020; 39:101014. [PMID: 32413586 PMCID: PMC7260680 DOI: 10.1016/j.molmet.2020.101014] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 04/24/2020] [Accepted: 05/04/2020] [Indexed: 12/16/2022] Open
Abstract
Objectives Our study shows that glucagon-like peptide-1 (GLP-1) is secreted within human islets and may play an unexpectedly important paracrine role in islet physiology and pathophysiology. It is known that α cells within rodent and human pancreatic islets are capable of secreting GLP-1, but little is known about the functional role that islet-derived GLP-1 plays in human islets. Methods We used flow cytometry, immunohistochemistry, perifusions, and calcium imaging techniques to analyse GLP-1 expression and function in islets isolated from cadaveric human donors with or without type 2 diabetes. We also used immunohistochemistry to analyse GLP-1 expression within islets from pancreatic biopsies obtained from living donors. Results We have demonstrated that human islets secrete ∼50-fold more GLP-1 than murine islets and that ∼40% of the total human α cells contain GLP-1. Our results also confirm that dipeptidyl peptidase-4 (DPP4) is expressed in α cells. Sitagliptin increased GLP-1 secretion from cultured human islets but did not enhance glucose-stimulated insulin secretion (GSIS) in islets from non-diabetic (ND) or type 2 diabetic (T2D) donors, suggesting that β cell GLP-1 receptors (GLP-1R) may already be maximally activated. Therefore, we tested the effects of exendin-9, a GLP-1R antagonist. Exendin-9 was shown to reduce GSIS by 39% and 61% in ND islets and T2D islets, respectively. We also observed significantly more GLP-1+ α cells in T2D islets compared with ND islets obtained from cadaveric donors. Furthermore, GLP-1+ α cells were also identified in pancreatic islet sections obtained from living donors undergoing surgery. Conclusions In summary, we demonstrated that human islets secrete robust amounts of GLP-1 from an α cell subpopulation and that GLP-1R signalling may support GSIS to a greater extent in T2D islets. Here we show that glucagon-like peptide-1 (GLP-1) is secreted from a subpopulation of α cells within human islets. Human islets secrete ∼50-fold more GLP-1 than murine islets and that ∼40% of the total human α cells contain GLP-1. We observed significantly more GLP-1+ α cells in islets from donors with type 2 diabetes than in islets from donors with no diabetes. GLP-1+ α cells can also be detected in pancreatic islet sections obtained from living donors undergoing surgery. GLP-1 receptor signaling may support insulin secretion to a greater extent in type 2 diabetes.
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Affiliation(s)
- Scott A Campbell
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Dominic P Golec
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Matt Hubert
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Janyne Johnson
- Alberta Diabetes Institute and the Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Nicole Salamon
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Amy Barr
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Patrick E MacDonald
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Koenraad Philippaert
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Peter E Light
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada.
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18
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Drug discovery approaches targeting the incretin pathway. Bioorg Chem 2020; 99:103810. [PMID: 32325333 DOI: 10.1016/j.bioorg.2020.103810] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/20/2020] [Accepted: 03/29/2020] [Indexed: 12/20/2022]
Abstract
Incretin pathway plays an important role in the development of diabetes medications. Interventions in DPP-4 and GLP-1 receptor have shown remarkable efficacy in experimental and clinical studies and imperatively become one of the most promising therapeutic approaches in the T2DM drug discovery pipeline. Herein, we analyzed the actionmechanismsof DPP-4 and GLP-1 receptor targeting the incretin pathway in T2DM treatment. We gave an insight into the structural requirements for the potent DPP-4 inhibitors and revealed a classification of DPP-4 inhibitors by stressing on the binding modes of these ligands to the enzyme. We then reviewed the drug discovery strategies for the development of peptide and non-peptide GLP-1 receptor agonists (GLP-1 RAs). Furthermore, the drug design strategies for DPP-4 inhibitors and GLP-1R agonists were detailed accurately. This review might provide an efficient evidence for the highly potent and selective DPP-4 inhibitors and the GLP-1 RAs, as novel medicines for patients suffering from T2DM.
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19
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Finan B, Capozzi ME, Campbell JE. Repositioning Glucagon Action in the Physiology and Pharmacology of Diabetes. Diabetes 2020; 69:532-541. [PMID: 31178432 PMCID: PMC7085250 DOI: 10.2337/dbi19-0004] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/30/2019] [Indexed: 01/03/2023]
Abstract
Glucagon is historically described as the counterregulatory hormone to insulin, induced by fasting/hypoglycemia to raise blood glucose through action mediated in the liver. However, it is becoming clear that the biology of glucagon is much more complex and extends beyond hepatic actions to exert control on glucose metabolism. We discuss the inconsistencies with the canonical view that glucagon is primarily a hyperglycemic agent driven by fasting/hypoglycemia and highlight the recent advances that have reshaped the metabolic role of glucagon. These concepts are placed within the context of both normal physiology and the pathophysiology of disease and then extended to discuss emerging strategies that incorporate glucagon agonism in the pharmacology of treating diabetes.
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Affiliation(s)
- Brian Finan
- Novo Nordisk Research Center, Indianapolis, IN
| | - Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | - Jonathan E Campbell
- Duke Molecular Physiology Institute, Duke University, Durham, NC
- Division of Endocrinology, Department of Medicine, Duke University, Durham, NC
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
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20
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Müller TD, Finan B, Bloom SR, D'Alessio D, Drucker DJ, Flatt PR, Fritsche A, Gribble F, Grill HJ, Habener JF, Holst JJ, Langhans W, Meier JJ, Nauck MA, Perez-Tilve D, Pocai A, Reimann F, Sandoval DA, Schwartz TW, Seeley RJ, Stemmer K, Tang-Christensen M, Woods SC, DiMarchi RD, Tschöp MH. Glucagon-like peptide 1 (GLP-1). Mol Metab 2019; 30:72-130. [PMID: 31767182 PMCID: PMC6812410 DOI: 10.1016/j.molmet.2019.09.010] [Citation(s) in RCA: 893] [Impact Index Per Article: 178.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/10/2019] [Accepted: 09/22/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The glucagon-like peptide-1 (GLP-1) is a multifaceted hormone with broad pharmacological potential. Among the numerous metabolic effects of GLP-1 are the glucose-dependent stimulation of insulin secretion, decrease of gastric emptying, inhibition of food intake, increase of natriuresis and diuresis, and modulation of rodent β-cell proliferation. GLP-1 also has cardio- and neuroprotective effects, decreases inflammation and apoptosis, and has implications for learning and memory, reward behavior, and palatability. Biochemically modified for enhanced potency and sustained action, GLP-1 receptor agonists are successfully in clinical use for the treatment of type-2 diabetes, and several GLP-1-based pharmacotherapies are in clinical evaluation for the treatment of obesity. SCOPE OF REVIEW In this review, we provide a detailed overview on the multifaceted nature of GLP-1 and its pharmacology and discuss its therapeutic implications on various diseases. MAJOR CONCLUSIONS Since its discovery, GLP-1 has emerged as a pleiotropic hormone with a myriad of metabolic functions that go well beyond its classical identification as an incretin hormone. The numerous beneficial effects of GLP-1 render this hormone an interesting candidate for the development of pharmacotherapies to treat obesity, diabetes, and neurodegenerative disorders.
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Affiliation(s)
- T D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany.
| | - B Finan
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA
| | - S R Bloom
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - D D'Alessio
- Division of Endocrinology, Duke University Medical Center, Durham, NC, USA
| | - D J Drucker
- The Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, University of Toronto, Ontario, M5G1X5, Canada
| | - P R Flatt
- SAAD Centre for Pharmacy & Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - A Fritsche
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany; Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, Tübingen, Germany
| | - F Gribble
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - H J Grill
- Institute of Diabetes, Obesity and Metabolism, Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - J F Habener
- Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Harvard University, Boston, MA, USA
| | - J J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - W Langhans
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - J J Meier
- Diabetes Division, St Josef Hospital, Ruhr-University Bochum, Bochum, Germany
| | - M A Nauck
- Diabetes Center Bochum-Hattingen, St Josef Hospital (Ruhr-Universität Bochum), Bochum, Germany
| | - D Perez-Tilve
- Department of Internal Medicine, University of Cincinnati-College of Medicine, Cincinnati, OH, USA
| | - A Pocai
- Cardiovascular & ImmunoMetabolism, Janssen Research & Development, Welsh and McKean Roads, Spring House, PA, 19477, USA
| | - F Reimann
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - D A Sandoval
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - T W Schwartz
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, DL-2200, Copenhagen, Denmark; Department of Biomedical Sciences, University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - R J Seeley
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - K Stemmer
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - M Tang-Christensen
- Obesity Research, Global Drug Discovery, Novo Nordisk A/S, Måløv, Denmark
| | - S C Woods
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, USA
| | - R D DiMarchi
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA; Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - M H Tschöp
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany; Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
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21
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Knudsen LB. Inventing Liraglutide, a Glucagon-Like Peptide-1 Analogue, for the Treatment of Diabetes and Obesity. ACS Pharmacol Transl Sci 2019; 2:468-484. [PMID: 32259078 DOI: 10.1021/acsptsci.9b00048] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Indexed: 01/08/2023]
Abstract
Glucagon-like peptide-1 (GLP-1) has been in focus since the early 1980s as a long looked for incretin hormone, released from the gastrointestinal tract and with an important effect on glucose-dependent insulin secretion, providing efficient glucose lowering, with little risk for hypoglycemia. The enzyme dipeptidyl peptidase-4 (DPP-4) degrades GLP-1 very fast, and the remaining metabolite is cleared rapidly by the kidneys. Liraglutide is a fatty acid acylated analogue of GLP-1 that provides efficacy for 24 h/day. The mechanism of action for liraglutide is reviewed in detail with focus on pancreatic efficacy and safety, thyroid safety, and weight loss mechanism. Evolving science hypothesizes that GLP-1 has important effects on atherosclerosis, relevant for the cardiovascular benefit seen in the treatment of diabetes and obesity. Also, GLP-1 may be relevant in neurodegenerative diseases.
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Affiliation(s)
- Lotte Bjerre Knudsen
- Global Drug Discovery, Novo Nordisk, Novo Nordisk Park, DK-2760 Maaloev, Denmark
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22
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Al-Zamel N, Al-Sabah S, Luqmani Y, Adi L, Chacko S, Schneider TD, Krasel C. A Dual GLP-1/GIP Receptor Agonist Does Not Antagonize Glucagon at Its Receptor but May Act as a Biased Agonist at the GLP-1 Receptor. Int J Mol Sci 2019; 20:ijms20143532. [PMID: 31330984 PMCID: PMC6678630 DOI: 10.3390/ijms20143532] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/06/2019] [Accepted: 07/12/2019] [Indexed: 12/25/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are important regulators of metabolism, making their receptors (GLP-1R and GIPR) attractive targets in the treatment of type 2 diabetes mellitus (T2DM). GLP-1R agonists are used clinically to treat T2DM but the use of GIPR agonists remains controversial. Recent studies suggest that simultaneous activation of GLP-1R and GIPR with a single peptide provides superior glycemic control with fewer adverse effects than activation of GLP-1R alone. We investigated the signaling properties of a recently reported dual-incretin receptor agonist (P18). GLP-1R, GIPR, and the closely related glucagon receptor (GCGR) were expressed in HEK-293 cells. Activation of adenylate cyclase via Gαs was monitored using a luciferase-linked reporter gene (CRE-Luc) assay. Arrestin recruitment was monitored using a bioluminescence resonance energy transfer (BRET) assay. GLP-1, GIP, and glucagon displayed exquisite selectivity for their receptors in the CRE-Luc assay. P18 activated GLP-1R with similar potency to GLP-1 and GIPR with higher potency than GIP. Interestingly, P18 was less effective than GLP-1 at recruiting arrestin to GLP-1R and was inactive at GCGR. These data suggest that P18 can act as both a dual-incretin receptor agonist, and as a G protein-biased agonist at GLP-1R.
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Affiliation(s)
- Noura Al-Zamel
- Department of Pharmacology & Toxicology, Faculty of Medicine, Kuwait University, PO Box 24923, 13110 Safat, Kuwait
| | - Suleiman Al-Sabah
- Department of Pharmacology & Toxicology, Faculty of Medicine, Kuwait University, PO Box 24923, 13110 Safat, Kuwait.
| | - Yunus Luqmani
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Kuwait University, PO Box 24923, 13110 Safat, Kuwait
| | - Lobna Adi
- Department of Pharmacology & Toxicology, Faculty of Medicine, Kuwait University, PO Box 24923, 13110 Safat, Kuwait
| | - Siby Chacko
- Department of Pharmacology & Toxicology, Faculty of Medicine, Kuwait University, PO Box 24923, 13110 Safat, Kuwait
| | - Tom Dario Schneider
- Institute of Forensic Medicine, Department of Forensic Pharmacology and Toxicology, University of Zurich, 190/52 CH-8057 Zurich, Switzerland
| | - Cornelius Krasel
- School of Pharmacy, Institute for Pharmacology and Toxicology, The Philipps University of Marburg, Karl-von-Frisch-Straße, 135033 Marburg, Germany
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23
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Salehi M, Purnell JQ. The Role of Glucagon-Like Peptide-1 in Energy Homeostasis. Metab Syndr Relat Disord 2019; 17:183-191. [PMID: 30720393 DOI: 10.1089/met.2018.0088] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Energy homeostasis is coordinated by bidirectional communication pathways between the brain and peripheral organs, including adipose tissue, muscle, the pancreas, liver, and gut. Disruption of the integrated chemical, hormonal, and neuronal signals that constitute the gut-brain axis significantly contributes to disorders of metabolism and body weight. Initial studies of glucagon-like peptide-1 (GLP-1), a gut hormone released in response to the ingestion of nutrients, focused on its incretin actions to improve postprandial glucose homeostasis by enhancing meal-induced insulin secretion. However, GLP-1 is also a key player in the gut-brain regulatory axis with multiple effects on appetite and energy metabolism outside of its peripheral glucoregulatory actions. In this review, we explore the function of GLP-1 as a component of the gut-brain axis in the regulation of energy homeostasis, and consider the implications of this role for the development of therapeutic treatment options for obesity.
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Affiliation(s)
- Marzieh Salehi
- 1 Division of Diabetes, Department of Internal Medicine, University of Texas Health at San Antonio, San Antonio, Texas.,2 Bartter Research Unit, Audie Murphy Hospital, South Texas Veteran Health Care System, San Antonio, Texas
| | - Jonathan Q Purnell
- 3 The Knight Cardiovascular Institute, Mailcode MDYMI, Oregon Health and Science University, Portland, Oregon
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Knudsen LB, Lau J. The Discovery and Development of Liraglutide and Semaglutide. Front Endocrinol (Lausanne) 2019; 10:155. [PMID: 31031702 PMCID: PMC6474072 DOI: 10.3389/fendo.2019.00155] [Citation(s) in RCA: 397] [Impact Index Per Article: 79.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 02/21/2019] [Indexed: 12/12/2022] Open
Abstract
The discovery of glucagon-like peptide-1 (GLP-1), an incretin hormone with important effects on glycemic control and body weight regulation, led to efforts to extend its half-life and make it therapeutically effective in people with type 2 diabetes (T2D). The development of short- and then long-acting GLP-1 receptor agonists (GLP-1RAs) followed. Our article charts the discovery and development of the long-acting GLP-1 analogs liraglutide and, subsequently, semaglutide. We examine the chemistry employed in designing liraglutide and semaglutide, the human and non-human studies used to investigate their cellular targets and pharmacological effects, and ongoing investigations into new applications and formulations of these drugs. Reversible binding to albumin was used for the systemic protraction of liraglutide and semaglutide, with optimal fatty acid and linker combinations identified to maximize albumin binding while maintaining GLP-1 receptor (GLP-1R) potency. GLP-1RAs mediate their effects via this receptor, which is expressed in the pancreas, gastrointestinal tract, heart, lungs, kidneys, and brain. GLP-1Rs in the pancreas and brain have been shown to account for the respective improvements in glycemic control and body weight that are evident with liraglutide and semaglutide. Both liraglutide and semaglutide also positively affect cardiovascular (CV) outcomes in individuals with T2D, although the precise mechanism is still being explored. Significant weight loss, through an effect to reduce energy intake, led to the approval of liraglutide (3.0 mg) for the treatment of obesity, an indication currently under investigation with semaglutide. Other ongoing investigations with semaglutide include the treatment of non-alcoholic fatty liver disease (NASH) and its use in an oral formulation for the treatment of T2D. In summary, rational design has led to the development of two long-acting GLP-1 analogs, liraglutide and semaglutide, that have made a vast contribution to the management of T2D in terms of improvements in glycemic control, body weight, blood pressure, lipids, beta-cell function, and CV outcomes. Furthermore, the development of an oral formulation for semaglutide may provide individuals with additional benefits in relation to treatment adherence. In addition to T2D, liraglutide is used in the treatment of obesity, while semaglutide is currently under investigation for use in obesity and NASH.
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Affiliation(s)
- Lotte Bjerre Knudsen
- Global Drug Discovery, Novo Nordisk A/S, Måløv, Denmark
- *Correspondence: Lotte Bjerre Knudsen
| | - Jesper Lau
- Global Research Technology, Novo Nordisk A/S, Måløv, Denmark
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Karageorgos V, Venihaki M, Sakellaris S, Pardalos M, Kontakis G, Matsoukas MT, Gravanis A, Margioris A, Liapakis G. Current understanding of the structure and function of family B GPCRs to design novel drugs. Hormones (Athens) 2018; 17:45-59. [PMID: 29858864 DOI: 10.1007/s42000-018-0009-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 01/25/2018] [Indexed: 01/10/2023]
Abstract
Family B of G-protein-coupled receptors (GPCRs) and their ligands play a central role in a number of homeostatic mechanisms in the endocrine, gastrointestinal, skeletal, immune, cardiovascular and central nervous systems. Alterations in family B GPCR-regulated homeostatic mechanisms may cause a variety of potentially life-threatening conditions, signifying the necessity to develop novel ligands targeting these receptors. Obtaining structural and functional information on family B GPCRs will accelerate the development of novel drugs to target these receptors. Family B GPCRs are proteins that span the plasma membrane seven times, thus forming seven transmembrane domains (TM1-TM7) which are connected to each other by three extracellular (EL) and three intracellular (IL) loops. In addition, these receptors have a long extracellular N-domain and an intracellular C-tail. The upper parts of the TMs and ELs form the J-domain of receptors. The C-terminal region of peptides first binds to the N-domain of receptors. This 'first-step' interaction orients the N-terminal region of peptides towards the J-domain of receptors, thus resulting in a 'second-step' of ligand-receptor interaction that activates the receptor. Activation-associated structural changes of receptors are transmitted through TMs to their intracellular regions and are responsible for their interaction with the G proteins and activation of the latter, thus resulting in a biological effect. This review summarizes the current information regarding the structure and function of family B GPCRs and their physiological and pathophysiological roles.
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Affiliation(s)
- Vlasios Karageorgos
- Department of Pharmacology, School of Medicine, University of Crete, Voutes, 71003, Heraklion, Crete, Greece
| | - Maria Venihaki
- Department of Clinical Chemistry, School of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Stelios Sakellaris
- Department of Pharmacology, School of Medicine, University of Crete, Voutes, 71003, Heraklion, Crete, Greece
| | - Michail Pardalos
- Department of Pharmacology, School of Medicine, University of Crete, Voutes, 71003, Heraklion, Crete, Greece
| | - George Kontakis
- Department of Orthopedics, University Hospital of Heraklion, Crete, Greece
| | | | - Achille Gravanis
- Department of Pharmacology, School of Medicine, University of Crete, Voutes, 71003, Heraklion, Crete, Greece
| | - Andreas Margioris
- Department of Clinical Chemistry, School of Medicine, University of Crete, Heraklion, Crete, Greece
| | - George Liapakis
- Department of Pharmacology, School of Medicine, University of Crete, Voutes, 71003, Heraklion, Crete, Greece.
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Li Y, Cui T, Kong X, Yi X, Kong D, Zhang J, Liu C, Gong M. Nanoparticles induced by embedding self-assembling cassette into glucagon-like peptide 1 for improving in vivo stability. FASEB J 2018; 32:2992-3004. [PMID: 29401602 DOI: 10.1096/fj.201701033rrr] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The multiple physiologic characteristics of glucagon-like peptide 1 (GLP-1) make it a promising drug candidate for treating type 2 diabetes mellitus. However, the half-life of GLP-1 is short as a result of degradation by dipeptidyl peptidase IV and renal clearance. Stabilizing GLP-1 is therefore critical for its use in drug development. Self-assembling peptides are a class of peptides that undergo spontaneous assembly into ordered nanostructures. Recently, studies of self-assembling peptides as drug carriers have increased because of their enhanced stability. In the present study, GLP-1 was modified to incorporate the structural characteristics of self-assembling peptides aiming to generate a self-assembling GLP-1 derivative. Receptor binding capacity and insulinotropic effects were measured to investigate the physiologic functions of GLP-1, along with morphologic approaches to observe supramolecular formation on self-assembly at the nano scale. Finally, blood glucose regulation and body weight were monitored after administration of selected derivatives. Our findings revealed that cadyglp1e and cadyglp1m both exhibited improved stability even though different nanoshapes were observed for these two self-assembling peptides. Both cadyglp1e and cadyglp1m retained glucoregulatory activity after insulin stimulation and were potent drug candidates for long-acting GLP-1 derivatives to treat type 2 diabetes mellitus. Our findings support the feasibility of introducing self-assembly functions into peptides with poor stabilities, such as GLP-1.-Li, Y., Cui, T., Kong, X., Yi, X., Kong, D., Zhang, J., Liu, C., Gong, M. Nanoparticles induced by embedding self-assembling cassette into glucagon-like peptide 1 for improving in vivo stability.
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Affiliation(s)
- Ying Li
- Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Tao Cui
- Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Xiaodong Kong
- Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Xiulin Yi
- State Key Laboratory of Drug Delivery Technology and Pharmacokinetics, Tianjin Institute of Pharmaceutical Research, Tianjin, China
| | - Dexin Kong
- Department of Pharmacy, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), Tianjin Medical University, Tianjin, China
| | - Jianning Zhang
- Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Changxiao Liu
- Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Min Gong
- Department of Pharmacy, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), Tianjin Medical University, Tianjin, China
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27
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Graaf CD, Donnelly D, Wootten D, Lau J, Sexton PM, Miller LJ, Ahn JM, Liao J, Fletcher MM, Yang D, Brown AJH, Zhou C, Deng J, Wang MW. Glucagon-Like Peptide-1 and Its Class B G Protein-Coupled Receptors: A Long March to Therapeutic Successes. Pharmacol Rev 2017; 68:954-1013. [PMID: 27630114 PMCID: PMC5050443 DOI: 10.1124/pr.115.011395] [Citation(s) in RCA: 229] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The glucagon-like peptide (GLP)-1 receptor (GLP-1R) is a class B G protein-coupled receptor (GPCR) that mediates the action of GLP-1, a peptide hormone secreted from three major tissues in humans, enteroendocrine L cells in the distal intestine, α cells in the pancreas, and the central nervous system, which exerts important actions useful in the management of type 2 diabetes mellitus and obesity, including glucose homeostasis and regulation of gastric motility and food intake. Peptidic analogs of GLP-1 have been successfully developed with enhanced bioavailability and pharmacological activity. Physiologic and biochemical studies with truncated, chimeric, and mutated peptides and GLP-1R variants, together with ligand-bound crystal structures of the extracellular domain and the first three-dimensional structures of the 7-helical transmembrane domain of class B GPCRs, have provided the basis for a two-domain-binding mechanism of GLP-1 with its cognate receptor. Although efforts in discovering therapeutically viable nonpeptidic GLP-1R agonists have been hampered, small-molecule modulators offer complementary chemical tools to peptide analogs to investigate ligand-directed biased cellular signaling of GLP-1R. The integrated pharmacological and structural information of different GLP-1 analogs and homologous receptors give new insights into the molecular determinants of GLP-1R ligand selectivity and functional activity, thereby providing novel opportunities in the design and development of more efficacious agents to treat metabolic disorders.
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Affiliation(s)
- Chris de Graaf
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Dan Donnelly
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Denise Wootten
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Jesper Lau
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Patrick M Sexton
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Laurence J Miller
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Jung-Mo Ahn
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Jiayu Liao
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Madeleine M Fletcher
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Dehua Yang
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Alastair J H Brown
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Caihong Zhou
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Jiejie Deng
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Ming-Wei Wang
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
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Lee S, Lee DY. Glucagon-like peptide-1 and glucagon-like peptide-1 receptor agonists in the treatment of type 2 diabetes. Ann Pediatr Endocrinol Metab 2017; 22:15-26. [PMID: 28443255 PMCID: PMC5401818 DOI: 10.6065/apem.2017.22.1.15] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 03/30/2017] [Accepted: 03/30/2017] [Indexed: 12/13/2022] Open
Abstract
The prevalence of type 2 diabetes (T2D) is increasing worldwide. Patients with T2D suffer from various diabetes-related complications. Since there are many patients with T2D that cannot be controlled by previously developed drugs, it has been necessary to develop new drugs, one of which is a glucagon-like peptide-1 (GLP-1) based therapy. GLP-1 has been shown to ameliorate diabetes-related conditions by augmenting pancreatic β-cell insulin secretion and having the low risk of causing hypoglycemia. Because of a very short half-life of GLP-1, many researches have been focused on the development of GLP-1 receptor (GLP-1R) agonists with long half-lives such as exenatide and dulaglutide. Now GLP-1R agonists have a variety of dosing-cycle forms to meet the needs of various patients. In this article, we review the physiological features of GLP-1, the effects of GLP-1 on T2D, the features of several GLP-1R agonists, and the therapeutic effect on T2D.
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Affiliation(s)
- Seungah Lee
- Department of Bioengineering, College of Engineering, and BK21 PLUS Future Biopharmaceutical Human Resources Training and Research Team, Hanyang University, Seoul, Korea
| | - Dong Yun Lee
- Department of Bioengineering, College of Engineering, and BK21 PLUS Future Biopharmaceutical Human Resources Training and Research Team, Hanyang University, Seoul, Korea.,Institute of Nano Science & Technology (INST), Hanyang University, Seoul, Korea
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29
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Wootten D, Reynolds CA, Smith KJ, Mobarec JC, Furness SGB, Miller LJ, Christopoulos A, Sexton PM. Key interactions by conserved polar amino acids located at the transmembrane helical boundaries in Class B GPCRs modulate activation, effector specificity and biased signalling in the glucagon-like peptide-1 receptor. Biochem Pharmacol 2016; 118:68-87. [PMID: 27569426 PMCID: PMC5063953 DOI: 10.1016/j.bcp.2016.08.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 08/15/2016] [Indexed: 11/28/2022]
Abstract
Class B GPCRs can activate multiple signalling effectors with the potential to exhibit biased agonism in response to ligand stimulation. Previously, we highlighted key TM domain polar amino acids that were crucial for the function of the GLP-1 receptor, a key therapeutic target for diabetes and obesity. Using a combination of mutagenesis, pharmacological characterisation, mathematical and computational molecular modelling, this study identifies additional highly conserved polar residues located towards the TM helical boundaries of Class B GPCRs that are important for GLP-1 receptor stability and/or controlling signalling specificity and biased agonism. This includes (i) three positively charged residues (R3.30227, K4.64288, R5.40310) located at the extracellular boundaries of TMs 3, 4 and 5 that are predicted in molecular models to stabilise extracellular loop 2, a crucial domain for ligand affinity and receptor activation; (ii) a predicted hydrogen bond network between residues located in TMs 2 (R2.46176), 6 (R6.37348) and 7 (N7.61406 and E7.63408) at the cytoplasmic face of the receptor that is important for stabilising the inactive receptor and directing signalling specificity, (iii) residues at the bottom of TM 5 (R5.56326) and TM6 (K6.35346 and K6.40351) that are crucial for receptor activation and downstream signalling; (iv) residues predicted to be involved in stabilisation of TM4 (N2.52182 and Y3.52250) that also influence cell signalling. Collectively, this work expands our understanding of peptide-mediated signalling by the GLP-1 receptor.
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Affiliation(s)
- Denise Wootten
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria 3052, Australia.
| | - Christopher A Reynolds
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
| | - Kevin J Smith
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
| | - Juan C Mobarec
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
| | - Sebastian G B Furness
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria 3052, Australia
| | - Laurence J Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ 85259, USA
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria 3052, Australia
| | - Patrick M Sexton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria 3052, Australia.
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30
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Hu LD, Zhang YL, Wang H, Peng XY, Wang Y. Highly efficient detection of insulinotropic action of glucagon via GLP-1 receptor in mice pancreatic beta-cell with a novel perfusion microchip. CHINESE CHEM LETT 2016. [DOI: 10.1016/j.cclet.2016.05.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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31
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Hennen S, Kodra JT, Soroka V, Krogh BO, Wu X, Kaastrup P, Ørskov C, Rønn SG, Schluckebier G, Barbateskovic S, Gandhi PS, Reedtz-Runge S. Structural insight into antibody-mediated antagonism of the Glucagon-like peptide-1 Receptor. Sci Rep 2016; 6:26236. [PMID: 27196125 PMCID: PMC4872540 DOI: 10.1038/srep26236] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 04/28/2016] [Indexed: 01/14/2023] Open
Abstract
The Glucagon-like peptide-1 receptor (GLP-1R) is a member of the class B G protein-coupled receptor (GPCR) family and a well-established target for the treatment of type 2 diabetes. The N-terminal extracellular domain (ECD) of GLP-1R is important for GLP-1 binding and the crystal structure of the GLP-1/ECD complex was reported previously. The first structure of a class B GPCR transmembrane (TM) domain was solved recently, but the full length receptor structure is still not well understood. Here we describe the molecular details of antibody-mediated antagonism of the GLP-1R using both in vitro pharmacology and x-ray crystallography. We showed that the antibody Fab fragment (Fab 3F52) blocked the GLP-1 binding site of the ECD directly and thereby acts as a competitive antagonist of native GLP-1. Interestingly, Fab 3F52 also blocked a short peptide agonist believed to engage primarily the transmembrane and extracellular loop region of GLP-1R, whereas functionality of an allosteric small-molecule agonist was not inhibited. This study has implications for the structural understanding of the GLP-1R and related class B GPCRs, which is important for the development of new and improved therapeutics targeting these receptors.
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Affiliation(s)
- Stephanie Hennen
- Incretin Biology, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark
| | - János T Kodra
- Protein &Peptide Chemistry 3, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark
| | - Vladyslav Soroka
- Protein Structure, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark
| | - Berit O Krogh
- Yeast Expression Systems, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark
| | - Xiaoai Wu
- Protein Chemistry 1, Novo Nordisk A/S, Novo Nordisk China R&D, Beijing, China
| | - Peter Kaastrup
- Antibody Technology, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark
| | - Cathrine Ørskov
- Incretin Biology, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark
| | - Sif G Rønn
- Incretin Biology, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark
| | - Gerd Schluckebier
- Protein Structure, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark
| | | | - Prafull S Gandhi
- Protein Interaction, Novo Nordisk A/S, Novo Nordisk Park, DK-2760, Måløv, Denmark
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32
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Zhao LH, Yin Y, Yang D, Liu B, Hou L, Wang X, Pal K, Jiang Y, Feng Y, Cai X, Dai A, Liu M, Wang MW, Melcher K, Xu HE. Differential Requirement of the Extracellular Domain in Activation of Class B G Protein-coupled Receptors. J Biol Chem 2016; 291:15119-30. [PMID: 27226600 DOI: 10.1074/jbc.m116.726620] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Indexed: 12/16/2022] Open
Abstract
G protein-coupled receptors (GPCRs) from the secretin-like (class B) family are key players in hormonal homeostasis and are important drug targets for the treatment of metabolic disorders and neuronal diseases. They consist of a large N-terminal extracellular domain (ECD) and a transmembrane domain (TMD) with the GPCR signature of seven transmembrane helices. Class B GPCRs are activated by peptide hormones with their C termini bound to the receptor ECD and their N termini bound to the TMD. It is thought that the ECD functions as an affinity trap to bind and localize the hormone to the receptor. This in turn would allow the hormone N terminus to insert into the TMD and induce conformational changes of the TMD to activate downstream signaling. In contrast to this prevailing model, we demonstrate that human class B GPCRs vary widely in their requirement of the ECD for activation. In one group, represented by corticotrophin-releasing factor receptor 1 (CRF1R), parathyroid hormone receptor (PTH1R), and pituitary adenylate cyclase activating polypeptide type 1 receptor (PAC1R), the ECD requirement for high affinity hormone binding can be bypassed by induced proximity and mass action effects, whereas in the other group, represented by glucagon receptor (GCGR) and glucagon-like peptide-1 receptor (GLP-1R), the ECD is required for signaling even when the hormone is covalently linked to the TMD. Furthermore, the activation of GLP-1R by small molecules that interact with the intracellular side of the receptor is dependent on the presence of its ECD, suggesting a direct role of the ECD in GLP-1R activation.
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Affiliation(s)
- Li-Hua Zhao
- From the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China, VARI-SIMM Center for Structure and Function of Drug Targets and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yanting Yin
- VARI-SIMM Center for Structure and Function of Drug Targets and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, Laboratory of Structural Sciences, Center for Structural Biology and Drug Discovery, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Dehua Yang
- The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Bo Liu
- VARI-SIMM Center for Structure and Function of Drug Targets and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Li Hou
- VARI-SIMM Center for Structure and Function of Drug Targets and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xiaoxi Wang
- VARI-SIMM Center for Structure and Function of Drug Targets and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Kuntal Pal
- Laboratory of Structural Sciences, Center for Structural Biology and Drug Discovery, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Yi Jiang
- VARI-SIMM Center for Structure and Function of Drug Targets and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yang Feng
- The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xiaoqing Cai
- The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Antao Dai
- The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Mingyao Liu
- From the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China, The Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas 77030
| | - Ming-Wei Wang
- The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203, China
| | - Karsten Melcher
- Laboratory of Structural Sciences, Center for Structural Biology and Drug Discovery, Van Andel Research Institute, Grand Rapids, Michigan 49503,
| | - H Eric Xu
- VARI-SIMM Center for Structure and Function of Drug Targets and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, Laboratory of Structural Sciences, Center for Structural Biology and Drug Discovery, Van Andel Research Institute, Grand Rapids, Michigan 49503,
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33
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Yang D, de Graaf C, Yang L, Song G, Dai A, Cai X, Feng Y, Reedtz-Runge S, Hanson MA, Yang H, Jiang H, Stevens RC, Wang MW. Structural Determinants of Binding the Seven-transmembrane Domain of the Glucagon-like Peptide-1 Receptor (GLP-1R). J Biol Chem 2016; 291:12991-3004. [PMID: 27059958 DOI: 10.1074/jbc.m116.721977] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Indexed: 12/25/2022] Open
Abstract
The glucagon-like peptide-1 receptor (GLP-1R) belongs to the secretin-like (class B) family of G protein-coupled receptors. Members of the class B family are distinguished by their large extracellular domain, which works cooperatively with the canonical seven-transmembrane (7TM) helical domain to signal in response to binding of various peptide hormones. We have combined structure-based site-specific mutational studies with molecular dynamics simulations of a full-length model of GLP-1R bound to multiple peptide ligand variants. Despite the high sequence similarity between GLP-1R and its closest structural homologue, the glucagon receptor (GCGR), nearly half of the 62 stably expressed mutants affected GLP-1R in a different manner than the corresponding mutants in GCGR. The molecular dynamics simulations of wild-type and mutant GLP-1R·ligand complexes provided molecular insights into GLP-1R-specific recognition mechanisms for the N terminus of GLP-1 by residues in the 7TM pocket and explained how glucagon-mimicking GLP-1 mutants restored binding affinity for (GCGR-mimicking) GLP-1R mutants. Structural analysis of the simulations suggested that peptide ligand binding mode variations in the 7TM binding pocket are facilitated by movement of the extracellular domain relative to the 7TM bundle. These differences in binding modes may account for the pharmacological differences between GLP-1 peptide variants.
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Affiliation(s)
- Dehua Yang
- From The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Shanghai 201203, China
| | - Chris de Graaf
- the Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Linlin Yang
- the Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China
| | - Gaojie Song
- the iHuman Institute, ShanghaiTech University, 99 Haike Road, Shanghai 201203, China
| | - Antao Dai
- From The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Shanghai 201203, China
| | - Xiaoqing Cai
- From The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Shanghai 201203, China
| | - Yang Feng
- From The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Shanghai 201203, China
| | - Steffen Reedtz-Runge
- the Department of Protein Structure, Novo Nordisk, Novo Nordisk Park, Malov 2760, Denmark
| | | | - Huaiyu Yang
- the Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China
| | - Hualiang Jiang
- the Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China
| | - Raymond C Stevens
- the iHuman Institute, ShanghaiTech University, 99 Haike Road, Shanghai 201203, China, the Bridge Institute, Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, California 90089, and
| | - Ming-Wei Wang
- From The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 189 Guo Shou Jing Road, Shanghai 201203, China, the School of Pharmacy, Fudan University, 826 Zhang Heng Road, Shanghai 201203, China
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34
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Dong M, Lam PCH, Orry A, Sexton PM, Christopoulos A, Abagyan R, Miller LJ. Use of Cysteine Trapping to Map Spatial Approximations between Residues Contributing to the Helix N-capping Motif of Secretin and Distinct Residues within Each of the Extracellular Loops of Its Receptor. J Biol Chem 2016; 291:5172-84. [PMID: 26740626 DOI: 10.1074/jbc.m115.706010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Indexed: 12/31/2022] Open
Abstract
Amino-terminal regions of secretin-family peptides contain key determinants for biological activity and binding specificity, although the nature of interactions with receptors is unclear. A helix N-capping motif within this region has been postulated to directly contribute to agonist activity while also stabilizing formation of a helix extending toward the peptide carboxyl terminus and docking within the receptor amino terminus. We used cysteine trapping to systematically explore spatial approximations between cysteines replacing each residue in this motif of secretin (sec), Phe(6), Thr(7), and Leu(10), and cysteines incorporated into the extracellular face of the receptor. Each peptide was a full agonist for cAMP, but had a lower binding affinity than natural hormone. These bound to COS cells expressing 61 receptor constructs incorporating cysteines in every position along each extracellular loop (ECL) and adjacent parts of transmembrane (TM) segments. Patterns of covalent labeling were distinct for each probe, with Cys(6)-sec labeling multiple residues in the carboxyl-terminal half of ECL2 and throughout ECL3, Cys(7)-sec predominantly labeling only single residues in the carboxyl-terminal end of ECL2 and the amino-terminal end of ECL3, and Cys(10)-sec not efficiently labeling any of these residues. These spatial constraints were used to refine our model of secretin bound to its receptor, now bringing ECL3 above the amino terminus of the ligand and revealing possible charge-charge interactions between this part of secretin and receptor residues in TM5, TM6, ECL2, and ECL3, which can orient and stabilize the peptide-receptor complex. This was validated by testing predicted approximations by mutagenesis and residue-residue complementation studies.
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Affiliation(s)
- Maoqing Dong
- From the Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona 85259
| | | | | | - Patrick M Sexton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville 3052, Australia, and
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville 3052, Australia, and
| | - Ruben Abagyan
- Molsoft LLC, La Jolla, California 92037, the Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92037
| | - Laurence J Miller
- From the Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona 85259,
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35
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Li Y, Wang Y, Wei Q, Zheng X, Tang L, Kong D, Gong M. Variant fatty acid-like molecules Conjugation, novel approaches for extending the stability of therapeutic peptides. Sci Rep 2015; 5:18039. [PMID: 26658631 PMCID: PMC4676015 DOI: 10.1038/srep18039] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 11/11/2015] [Indexed: 12/02/2022] Open
Abstract
The multiple physiological properties of glucagon-like peptide-1 (GLP-1) make it a promising drug candidate for the treatment of type 2 diabetes. However, the in vivo half-life of GLP-1 is short due to rapid degradation by dipeptidyl peptidase-IV (DPP-IV) and renal clearance. The poor stability of GLP-1 has significantly limited its clinical utility; however, many studies are focused on extending its stability. Fatty acid conjugation is a traditional approach for extending the stability of therapeutic peptides because of the high binding affinity of human serum albumin for fatty acids. However, the conjugate requires a complex synthetic approach, usually involving Lys and occasionally involving a linker. In the current study, we conjugated the GLP-1 molecule with fatty acid derivatives to simplify the synthesis steps. Human serum albumin binding assays indicated that the retained carboxyl groups of the fatty acids helped maintain a tight affinity to HSA. The conjugation of fatty acid-like molecules improved the stability and increased the binding affinity of GLP-1 to HSA. The use of fatty acid-like molecules as conjugating components allowed variant conjugation positions and freed carboxyl groups for other potential uses. This may be a novel, long-acting strategy for the development of therapeutic peptides.
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Affiliation(s)
- Ying Li
- Tianjin Neurological Institute, Tianjin Medical University General Hospital, China
| | - Yuli Wang
- Tianjin Institute of Pharmaceutical Research, China
| | - Qunchao Wei
- Tianjin Institute of Pharmaceutical Research, China
| | - Xuemin Zheng
- Tianjin Institute of Pharmaceutical Research, China
| | - Lida Tang
- Tianjin Institute of Pharmaceutical Research, China
| | - Dexin Kong
- Department of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Min Gong
- Tianjin Institute of Pharmaceutical Research, China.,Department of Pharmacy, Tianjin Medical University, Tianjin, China.,Department of Oncology, University of Oxford, UK
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36
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Weston C, Lu J, Li N, Barkan K, Richards GO, Roberts DJ, Skerry TM, Poyner D, Pardamwar M, Reynolds CA, Dowell SJ, Willars GB, Ladds G. Modulation of Glucagon Receptor Pharmacology by Receptor Activity-modifying Protein-2 (RAMP2). J Biol Chem 2015. [PMID: 26198634 PMCID: PMC4645630 DOI: 10.1074/jbc.m114.624601] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The glucagon and glucagon-like peptide-1 (GLP-1) receptors play important, opposing roles in regulating blood glucose levels. Consequently, these receptors have been identified as targets for novel diabetes treatments. However, drugs acting at the GLP-1 receptor, although having clinical efficacy, have been associated with severe adverse side-effects, and targeting of the glucagon receptor has yet to be successful. Here we use a combination of yeast reporter assays and mammalian systems to provide a more complete understanding of glucagon receptor signaling, considering the effect of multiple ligands, association with the receptor-interacting protein receptor activity-modifying protein-2 (RAMP2), and the role of individual G protein α-subunits. We demonstrate that RAMP2 alters both ligand selectivity and G protein preference of the glucagon receptor. Importantly, we also uncover novel cross-reactivity of therapeutically used GLP-1 receptor ligands at the glucagon receptor that is abolished by RAMP2 interaction. This study reveals the glucagon receptor as a previously unidentified target for GLP-1 receptor agonists and highlights a role for RAMP2 in regulating its pharmacology. Such previously unrecognized functions of RAMPs highlight the need to consider all receptor-interacting proteins in future drug development.
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Affiliation(s)
- Cathryn Weston
- From the Division of Biomedical Cell Biology, Warwick Medical School, University of Warwick, Coventry CV4 7AL, United Kingdom,
| | - Jing Lu
- the Department of Cell Physiology and Pharmacology, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Naichang Li
- the Department of Cell Physiology and Pharmacology, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Kerry Barkan
- From the Division of Biomedical Cell Biology, Warwick Medical School, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Gareth O Richards
- the Mellanby Centre for Bone Research, Department of Human Metabolism, University of Sheffield, Sheffield S10 2RX, United Kingdom
| | - David J Roberts
- the Mellanby Centre for Bone Research, Department of Human Metabolism, University of Sheffield, Sheffield S10 2RX, United Kingdom
| | - Timothy M Skerry
- the Mellanby Centre for Bone Research, Department of Human Metabolism, University of Sheffield, Sheffield S10 2RX, United Kingdom
| | - David Poyner
- the School of Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, United Kingdom
| | - Meenakshi Pardamwar
- the School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, United Kingdom, and
| | - Christopher A Reynolds
- the School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, United Kingdom, and
| | - Simon J Dowell
- the Department of Biological Sciences, Molecular Discovery Research, GlaxoSmithKline, Hertfordshire SG1 2NY, United Kingdom, and
| | - Gary B Willars
- the Department of Cell Physiology and Pharmacology, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Graham Ladds
- From the Division of Biomedical Cell Biology, Warwick Medical School, University of Warwick, Coventry CV4 7AL, United Kingdom, the Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
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37
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Moon MJ, Lee YN, Park S, Reyes-Alcaraz A, Hwang JI, Millar RP, Choe H, Seong JY. Ligand binding pocket formed by evolutionarily conserved residues in the glucagon-like peptide-1 (GLP-1) receptor core domain. J Biol Chem 2015; 290:5696-706. [PMID: 25561730 DOI: 10.1074/jbc.m114.612606] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1) plays a pivotal role in glucose homeostasis through its receptor GLP1R. Due to its multiple beneficial effects, GLP-1 has gained great attention for treatment of type 2 diabetes and obesity. However, little is known about the molecular mechanism underlying the interaction of GLP-1 with the heptahelical core domain of GLP1R conferring high affinity ligand binding and ligand-induced receptor activation. Here, using chimeric and point-mutated GLP1R, we determined that the evolutionarily conserved amino acid residue Arg(380) flanked by hydrophobic Leu(379) and Phe(381) in extracellular loop 3 (ECL3) may have an interaction with Asp(9) and Gly(4) of the GLP-1 peptide. The molecular modeling study showed that Ile(196) at transmembrane helix 2, Met(233) at ECL1, and Asn(302) at ECL2 of GLP1R have contacts with His(1) and Thr(7) of GLP-1. This study may shed light on the mechanism underlying high affinity interaction between the ligand and the binding pocket that is formed by these conserved residues in the GLP1R core domain.
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Affiliation(s)
- Mi Jin Moon
- From the Graduate School of Medicine, Korea University, Seoul 136-705, Republic of Korea
| | - Yoo-Na Lee
- From the Graduate School of Medicine, Korea University, Seoul 136-705, Republic of Korea
| | - Sumi Park
- From the Graduate School of Medicine, Korea University, Seoul 136-705, Republic of Korea
| | - Arfaxad Reyes-Alcaraz
- From the Graduate School of Medicine, Korea University, Seoul 136-705, Republic of Korea
| | - Jong-Ik Hwang
- From the Graduate School of Medicine, Korea University, Seoul 136-705, Republic of Korea
| | - Robert Peter Millar
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0028, Medical Research Council Receptor Biology Unit, and University of Cape Town, Cape Town 7925, South Africa, and Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH164TJ, Scotland, and
| | - Han Choe
- Department of Physiology and Bio-Medical Institute of Technology, University of Ulsan College of Medicine, Seoul 138-736, Korea
| | - Jae Young Seong
- From the Graduate School of Medicine, Korea University, Seoul 136-705, Republic of Korea,
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38
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WU LUSHENG, WANG JING, CHEN XIAOJIA, HONG AN. Expression, identification and biological effects of the novel recombination protein, PACAP38-NtA, with high bioactivity. Int J Mol Med 2014; 35:376-82. [DOI: 10.3892/ijmm.2014.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 11/07/2014] [Indexed: 11/06/2022] Open
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39
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Dong M, Koole C, Wootten D, Sexton PM, Miller LJ. Structural and functional insights into the juxtamembranous amino-terminal tail and extracellular loop regions of class B GPCRs. Br J Pharmacol 2014; 171:1085-101. [PMID: 23889342 DOI: 10.1111/bph.12293] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 06/22/2013] [Accepted: 06/29/2013] [Indexed: 12/24/2022] Open
Abstract
Class B guanine nucleotide-binding protein GPCRs share heptahelical topology and signalling via coupling with heterotrimeric G proteins typical of the entire superfamily of GPCRs. However, they also exhibit substantial structural differences from the more extensively studied class A GPCRs. Even their helical bundle region, most conserved across the superfamily, is predicted to differ from that of class A GPCRs. Much is now known about the conserved structure of the amino-terminal domain of class B GPCRs, coming from isolated NMR and crystal structures, but the orientation of that domain relative to the helical bundle is unknown, and even less is understood about the conformations of the juxtamembranous amino-terminal tail or of the extracellular loops linking the transmembrane segments. We now review what is known about the structure and function of these regions of class B GPCRs. This comes from indirect analysis of structure-function relationships elucidated by mutagenesis and/or ligand modification and from the more direct analysis of spatial approximation coming from photoaffinity labelling and cysteine trapping studies. Also reviewed are the limited studies of structure of some of these regions. No dominant theme was recognized for the structures or functional roles of distinct regions of these juxtamembranous portions of the class B GPCRs. Therefore, it is likely that a variety of molecular strategies can be engaged for docking of agonist ligands and for initiation of conformational changes in these receptors that would be expected to converge to a common molecular mechanism for activation of intracellular signalling cascades.
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Affiliation(s)
- M Dong
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, USA
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40
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Yang X, Li Y, Wang Y, Zheng X, Kong W, Meng F, Zhou Z, Liu C, Li Y, Gong M. Long-Acting GLP-1 Analogue in V-Shaped Conformation by Terminal Polylysine Modifications. Mol Pharm 2014; 11:4092-9. [PMID: 25243635 DOI: 10.1021/mp5002685] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Xue Yang
- Department of Pharmacy, Tianjin Traditional Medicine University, Tianjin, China
| | - Ying Li
- Tianjin Neurological
Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Yuli Wang
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
| | - Xuemin Zheng
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
| | - Weiling Kong
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
| | - Fancui Meng
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
| | - Zhixing Zhou
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
| | - Changxiao Liu
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
| | - Ying Li
- Tianjin Neurological
Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Min Gong
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
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41
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Abstract
Glucagon-like peptide 1 (GLP1) is an intestinal incretin that regulates glucose homeostasis through stimulation of insulin secretion from pancreatic β-cells and inhibits appetite by acting on the brain. Thus, it is a promising therapeutic agent for the treatment of type 2 diabetes mellitus and obesity. Studies using synteny and reconstructed ancestral chromosomes suggest that families for GLP1 and its receptor (GLP1R) have emerged through two rounds (2R) of whole genome duplication and local gene duplications before and after 2R. Exon duplications have also contributed to the expansion of the peptide family members. Specific changes in the amino acid sequence following exon/gene/genome duplications have established distinct yet related peptide and receptor families. These specific changes also confer selective interactions between GLP1 and GLP1R. In this review, we present a possible macro (genome level)- and micro (gene/exon level)-evolution mechanisms of GLP1 and GLP1R, which allows them to acquire selective interactions between this ligand-receptor pair. This information may provide critical insight for the development of potent therapeutic agents targeting GLP1R.
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Affiliation(s)
- Jong-Ik Hwang
- Graduate School of MedicineKorea University, Seoul 136-705, Republic of Korea
| | - Seongsik Yun
- Graduate School of MedicineKorea University, Seoul 136-705, Republic of Korea
| | - Mi Jin Moon
- Graduate School of MedicineKorea University, Seoul 136-705, Republic of Korea
| | - Cho Rong Park
- Graduate School of MedicineKorea University, Seoul 136-705, Republic of Korea
| | - Jae Young Seong
- Graduate School of MedicineKorea University, Seoul 136-705, Republic of Korea
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Underwood CR, Knudsen LB, Garibay PW, Peters GH, Reedtz-Runge S. Development of a cysteine-deprived and C-terminally truncated GLP-1 receptor. Peptides 2013; 49:100-8. [PMID: 24045233 DOI: 10.1016/j.peptides.2013.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 09/04/2013] [Accepted: 09/04/2013] [Indexed: 11/20/2022]
Abstract
The glucagon-like peptide-1 receptor (GLP-1R) belongs to family B of the G-protein coupled receptors (GPCRs), and has become a promising target for the treatment of type 2 diabetes. Here we describe the development and characterization of a fully functional cysteine-deprived and C-terminally truncated GLP-1R. Single cysteines were initially substituted with alanine, and functionally redundant cysteines were subsequently changed simultaneously. Our results indicate that Cys(174), Cys(226), Cys(296) and Cys(403) are important for the GLP-1-mediated response, whereas Cys(236), Cys(329), Cys(341), Cys(347), Cys(438), Cys(458) and Cys(462) are not. Extensive deletions were made in the C-terminal tail of GLP-1R in order to determine the limit for truncation. As for other family B GPCRs, we observed a direct correlation between the length of the C-terminal tail and specific binding of (125)I-GLP-1, indicating that the membrane proximal part of the C-terminal is involved in receptor expression at the cell surface. The results show that seven cysteines and more than half of the C-terminal tail can be removed from GLP-1R without compromising GLP-1 binding or function.
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Affiliation(s)
- Christina Rye Underwood
- Department of Incretin Biology, Novo Nordisk, DK-2820 Gentofte, Denmark; Department of Chemistry, MEMPHYS - Center for Biomembrane Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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43
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Recent advances in understanding GLP-1R (glucagon-like peptide-1 receptor) function. Biochem Soc Trans 2013; 41:172-9. [PMID: 23356279 DOI: 10.1042/bst20120236] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Type 2 diabetes is a major global health problem and there is ongoing research for new treatments to manage the disease. The GLP-1R (glucagon-like peptide-1 receptor) controls the physiological response to the incretin peptide, GLP-1, and is currently a major target for the development of therapeutics owing to the broad range of potential beneficial effects in Type 2 diabetes. These include promotion of glucose-dependent insulin secretion, increased insulin biosynthesis, preservation of β-cell mass, improved peripheral insulin sensitivity and promotion of weight loss. Despite this, our understanding of GLP-1R function is still limited, with the desired spectrum of GLP-1R-mediated signalling yet to be determined. We review the current understanding of GLP-1R function, in particular, highlighting recent contributions in the field on allosteric modulation, probe-dependence and ligand-directed signal bias and how these behaviours may influence future drug development.
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Park CR, Moon MJ, Park S, Kim DK, Cho EB, Millar RP, Hwang JI, Seong JY. A novel glucagon-related peptide (GCRP) and its receptor GCRPR account for coevolution of their family members in vertebrates. PLoS One 2013; 8:e65420. [PMID: 23776481 PMCID: PMC3679108 DOI: 10.1371/journal.pone.0065420] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 04/24/2013] [Indexed: 12/25/2022] Open
Abstract
The glucagon (GCG) peptide family consists of GCG, glucagon-like peptide 1 (GLP1), and GLP2, which are derived from a common GCG precursor, and the glucose-dependent insulinotropic polypeptide (GIP). These peptides interact with cognate receptors, GCGR, GLP1R, GLP2R, and GIPR, which belong to the secretin-like G protein-coupled receptor (GPCR) family. We used bioinformatics to identify genes encoding a novel GCG-related peptide (GCRP) and its cognate receptor, GCRPR. The GCRP and GCRPR genes were found in representative tetrapod taxa such as anole lizard, chicken, and Xenopus, and in teleosts including medaka, fugu, tetraodon, and stickleback. However, they were not present in mammals and zebrafish. Phylogenetic and genome synteny analyses showed that GCRP emerged through two rounds of whole genome duplication (2R) during early vertebrate evolution. GCRPR appears to have arisen by local tandem gene duplications from a common ancestor of GCRPR, GCGR, and GLP2R after 2R. Biochemical ligand-receptor interaction analyses revealed that GCRP had the highest affinity for GCRPR in comparison to other GCGR family members. Stimulation of chicken, Xenopus, and medaka GCRPRs activated Gαs-mediated signaling. In contrast to chicken and Xenopus GCRPRs, medaka GCRPR also induced Gαq/11-mediated signaling. Chimeric peptides and receptors showed that the K16M17K18 and G16Q17A18 motifs in GCRP and GLP1, respectively, may at least in part contribute to specific recognition of their cognate receptors through interaction with the receptor core domain. In conclusion, we present novel data demonstrating that GCRP and GCRPR evolved through gene/genome duplications followed by specific modifications that conferred selective recognition to this ligand-receptor pair.
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Affiliation(s)
- Cho Rong Park
- Laboratory of G-protein Coupled Receptors, Graduate School of Medicine Korea University, Seoul, Republic of Korea
| | - Mi Jin Moon
- Laboratory of G-protein Coupled Receptors, Graduate School of Medicine Korea University, Seoul, Republic of Korea
| | - Sumi Park
- Laboratory of G-protein Coupled Receptors, Graduate School of Medicine Korea University, Seoul, Republic of Korea
| | - Dong-Kyu Kim
- Laboratory of G-protein Coupled Receptors, Graduate School of Medicine Korea University, Seoul, Republic of Korea
| | - Eun Bee Cho
- Laboratory of G-protein Coupled Receptors, Graduate School of Medicine Korea University, Seoul, Republic of Korea
| | - Robert Peter Millar
- Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Hatfield, South Africa
- Medical Research Council Receptor Biology Unit, University of Cape Town, Observatory 7925, South Africa
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Scotland
| | - Jong-Ik Hwang
- Laboratory of G-protein Coupled Receptors, Graduate School of Medicine Korea University, Seoul, Republic of Korea
- * E-mail: (JIH); (JYS)
| | - Jae Young Seong
- Laboratory of G-protein Coupled Receptors, Graduate School of Medicine Korea University, Seoul, Republic of Korea
- * E-mail: (JIH); (JYS)
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45
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Hwang JI, Moon MJ, Park S, Kim DK, Cho EB, Ha N, Son GH, Kim K, Vaudry H, Seong JY. Expansion of secretin-like G protein-coupled receptors and their peptide ligands via local duplications before and after two rounds of whole-genome duplication. Mol Biol Evol 2013; 30:1119-30. [PMID: 23427277 DOI: 10.1093/molbev/mst031] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In humans, the secretin-like G protein-coupled receptor (GPCR) family comprises 15 members with 18 corresponding peptide ligand genes. Although members have been identified in a large variety of vertebrate and nonvertebrate species, the origin and relationship of these proteins remain unresolved. To address this issue, we employed large-scale genome comparisons to identify genome fragments with conserved synteny and matched these fragments to linkage groups in reconstructed early gnathostome ancestral chromosomes (GAC). This genome comparison revealed that most receptor and peptide genes were clustered in three GAC linkage groups and suggested that the ancestral forms of five peptide subfamilies (corticotropin-releasing hormone-like, calcitonin-like, parathyroid hormone-like, glucagon-like, and growth hormone-releasing hormone-like) and their cognate receptor families emerged through tandem local gene duplications before two rounds (2R) of whole-genome duplication. These subfamily genes have, then, been amplified by 2R whole-genome duplication, followed by additional local duplications and gene loss prior to the divergence of land vertebrates and teleosts. This study delineates a possible evolutionary scenario for whole secretin-like peptide and receptor family members and may shed light on evolutionary mechanisms for expansion of a gene family with a large number of paralogs.
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Affiliation(s)
- Jong-Ik Hwang
- Graduate School of Medicine, Korea University, Seoul, Republic of Korea
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46
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Patterson JT, Li P, Day JW, Gelfanov VM, Dimarchi RD. A hydrophobic site on the GLP-1 receptor extracellular domain orients the peptide ligand for signal transduction. Mol Metab 2013; 2:86-91. [PMID: 24199154 DOI: 10.1016/j.molmet.2013.01.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 12/26/2012] [Accepted: 01/03/2013] [Indexed: 11/24/2022] Open
Abstract
Structure-function studies have analyzed substitutions within the glucagon-like peptide-1 (GLP-1) sequence that increase resistance to proteolysis, however, the investigation into how such substitutions alter interactions at the GLP-1 receptor (GLP-1R) has captured less attention. This work describes our efforts at identifying relevant interactions between peptide ligands and the GLP-1R extracellular domain that contribute to the positioning of the peptide N-terminus for receptor activation. Alanine substitutions at hydrophilic (Glu127⁎ and Glu128⁎) and hydrophobic (Leu32⁎) GLP-1R residues were previously shown to differentially interact with GLP-1 and exendin-4. We examined if these receptor residues influence the activity of GLP-1- and exendin-4-based peptides containing either alanine or glycine at position 2. Additionally, a series of glucagon-based peptides were studied to determine how the central to C-terminal region affects activity. Our results suggest that peptide binding to the GLP-1R is largely driven by hydrophobic interactions with the extracellular domain that orient the N-terminus for activation.
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47
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Lockie SH, Heppner KM, Chaudhary N, Chabenne JR, Morgan DA, Veyrat-Durebex C, Ananthakrishnan G, Rohner-Jeanrenaud F, Drucker DJ, DiMarchi R, Rahmouni K, Oldfield BJ, Tschöp MH, Perez-Tilve D. Direct control of brown adipose tissue thermogenesis by central nervous system glucagon-like peptide-1 receptor signaling. Diabetes 2012; 61:2753-62. [PMID: 22933116 PMCID: PMC3478556 DOI: 10.2337/db11-1556] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We studied interscapular brown adipose tissue (iBAT) activity in wild-type (WT) and glucagon-like peptide 1 receptor (GLP-1R)-deficient mice after the administration of the proglucagon-derived peptides (PGDPs) glucagon-like peptide (GLP-1), glucagon (GCG), and oxyntomodulin (OXM) directly into the brain. Intracerebroventricular injection of PGDPs reduces body weight and increases iBAT thermogenesis. This was independent of changes in feeding and insulin responsiveness but correlated with increased activity of sympathetic fibers innervating brown adipose tissue (BAT). Despite being a GCG receptor agonist, OXM requires GLP-1R activation to induce iBAT thermogenesis. The increase in thermogenesis in WT mice correlates with increased expression of genes upregulated by adrenergic signaling and required for iBAT thermogenesis, including PGC1a and UCP-1. In spite of the increase in iBAT thermogenesis induced by GLP-1R activation in WT mice, Glp1r(-/-) mice exhibit a normal response to cold exposure, demonstrating that endogenous GLP-1R signaling is not essential for appropriate thermogenic response after cold exposure. Our data suggest that the increase in BAT thermogenesis may be an additional mechanism whereby pharmacological GLP-1R activation controls energy balance.
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Affiliation(s)
- Sarah H. Lockie
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, Ohio
- Department of Physiology, Monash University, Melbourne, Australia
| | - Kristy M. Heppner
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, Ohio
| | - Nilika Chaudhary
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, Ohio
| | | | - Donald A. Morgan
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Christelle Veyrat-Durebex
- Department of Internal Medicine, Laboratory of Metabolism, Division of Endocrinology, Diabetology and Nutrition, University of Geneva, Geneva, Switzerland
| | - Gayathri Ananthakrishnan
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, Ohio
| | - Françoise Rohner-Jeanrenaud
- Department of Internal Medicine, Laboratory of Metabolism, Division of Endocrinology, Diabetology and Nutrition, University of Geneva, Geneva, Switzerland
| | - Daniel J. Drucker
- Department of Medicine, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Richard DiMarchi
- Department of Chemistry, Indiana University, Bloomington, Indiana
| | - Kamal Rahmouni
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | | | - Matthias H. Tschöp
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, Ohio
| | - Diego Perez-Tilve
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, Ohio
- Corresponding author: Diego Perez-Tilve,
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48
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Fu Z, Kuang HY, Hao M, Gao XY, Liu Y, Shao N. Protection of exenatide for retinal ganglion cells with different glucose concentrations. Peptides 2012; 37:25-31. [PMID: 22727809 DOI: 10.1016/j.peptides.2012.06.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 06/12/2012] [Accepted: 06/12/2012] [Indexed: 12/30/2022]
Abstract
Exendin-4 is a peptide resembling glucagon-like peptide-1 (GLP-1), which has protective effects on nerve cells. However, the effects of Exendin-4 on retinal ganglion cells (RGC) are still under clear. The purpose of the present study is to demonstrate that exenatide prevents high- or low-glucose-induced retinal ganglion cell impairment. We observed the expression of GLP-1R in RGC-5 cells by immunofluorescence and Western blot. To investigate the effect of exenatide on RGC-5 cells incubated different glucose concentrations, CCK-8 measured the survival rates and electron microscopy detected cellular injury. The expression levels of Bcl-2 and Bax were analyzed by immunocytochemistry and Western blot. Exenatide protects RGC-5 from high- or low-glucose-induced cellular injury and the optimum concentration was 0.5μg/ml. Exenatide can inhibit high- or low-glucose-induced mitochondrial changes. Exenatide protects RGC-5 from high- or low-glucose-induced Bax increased and Bcl-2 decreased. Furthermore, the protective effect of exenatide could be inhibited by Exendin (9-39). These findings indicate that exenatide shows a neuroprotective effect for different glucose concentrations-induced RGC-5 cells injury. Exenatide could protect RGC-5 cells from degeneration or death, which may protect retinal function and have a potential value for patients with diabetic retinopathy.
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Affiliation(s)
- Zheng Fu
- Department of Endocrinology, Ningde Hospital, 352100 Fujian Province, China
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49
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Abstract
Members of the class B family of G protein-coupled receptors (GPCRs) bind peptide hormones and have causal roles in many diseases, ranging from diabetes and osteoporosis to anxiety. Although peptide, small-molecule, and antibody inhibitors of these GPCRs have been identified, structure-based descriptions of receptor antagonism are scarce. Here we report the mechanisms of glucagon receptor inhibition by blocking antibodies targeting the receptor's extracellular domain (ECD). These studies uncovered a role for the ECD as an intrinsic negative regulator of receptor activity. The crystal structure of the ECD in complex with the Fab fragment of one antibody, mAb1, reveals that this antibody inhibits glucagon receptor by occluding a surface extending across the entire hormone-binding cleft. A second antibody, mAb23, blocks glucagon binding and inhibits basal receptor activity, indicating that it is an inverse agonist and that the ECD can negatively regulate receptor activity independent of ligand binding. Biochemical analyses of receptor mutants in the context of a high-resolution ECD structure show that this previously unrecognized inhibitory activity of the ECD involves an interaction with the third extracellular loop of the receptor and suggest that glucagon-mediated structural changes in the ECD accompany receptor activation. These studies have implications for the design of drugs to treat class B GPCR-related diseases, including the potential for developing novel allosteric regulators that target the ECDs of these receptors.
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50
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Miller LJ, Dong M, Harikumar KG. Ligand binding and activation of the secretin receptor, a prototypic family B G protein-coupled receptor. Br J Pharmacol 2012; 166:18-26. [PMID: 21542831 DOI: 10.1111/j.1476-5381.2011.01463.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The secretin receptor is a prototypic member of family B G protein-coupled receptors that binds and responds to a linear 27-residue peptide natural ligand. The carboxyl-terminal region of this peptide assumes a helical conformation that occupies the peptide-binding cleft within the structurally complex disulphide-bonded amino-terminal domain of this receptor. The amino terminus of secretin is directed toward the core helical bundle domain of this receptor that seems to be structurally distinct from the analogous region of family A G protein-coupled receptors. This amino-terminal region of secretin is critical for its biological activity, to stimulate Gs coupling and the agonist-induced cAMP response. While the natural peptide ligand is known to span the two key receptor domains, with multiple residue-residue approximation constraints well established, the orientation of the receptor amino terminus relative to the receptor core helical bundle domain is still unclear. Fluorescence studies have established that the mid-region and carboxyl-terminal end of secretin are protected by the receptor peptide-binding cleft and the amino terminus of secretin is most exposed to the aqueous milieu as it is directed toward the receptor core, with the mid-region of the peptide becoming more exposed upon receptor activation. Like other family B peptide hormone receptors, the secretin receptor is constitutively present in a structurally specific homo-dimeric complex built around the lipid-exposed face of transmembrane segment four. This complex is important for facilitating G protein association and achieving the high affinity state of this receptor.
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Affiliation(s)
- Laurence J Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, USA.
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