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Gandasi NR, Gao R, Kothegala L, Pearce A, Santos C, Acreman S, Basco D, Benrick A, Chibalina MV, Clark A, Guida C, Harris M, Johnson PRV, Knudsen JG, Ma J, Miranda C, Shigeto M, Tarasov AI, Yeung HY, Thorens B, Asterholm IW, Zhang Q, Ramracheya R, Ladds G, Rorsman P. GLP-1 metabolite GLP-1(9-36) is a systemic inhibitor of mouse and human pancreatic islet glucagon secretion. Diabetologia 2024; 67:528-546. [PMID: 38127123 PMCID: PMC10844371 DOI: 10.1007/s00125-023-06060-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 10/18/2023] [Indexed: 12/23/2023]
Abstract
AIMS/HYPOTHESIS Diabetes mellitus is associated with impaired insulin secretion, often aggravated by oversecretion of glucagon. Therapeutic interventions should ideally correct both defects. Glucagon-like peptide 1 (GLP-1) has this capability but exactly how it exerts its glucagonostatic effect remains obscure. Following its release GLP-1 is rapidly degraded from GLP-1(7-36) to GLP-1(9-36). We hypothesised that the metabolite GLP-1(9-36) (previously believed to be biologically inactive) exerts a direct inhibitory effect on glucagon secretion and that this mechanism becomes impaired in diabetes. METHODS We used a combination of glucagon secretion measurements in mouse and human islets (including islets from donors with type 2 diabetes), total internal reflection fluorescence microscopy imaging of secretory granule dynamics, recordings of cytoplasmic Ca2+ and measurements of protein kinase A activity, immunocytochemistry, in vivo physiology and GTP-binding protein dissociation studies to explore how GLP-1 exerts its inhibitory effect on glucagon secretion and the role of the metabolite GLP-1(9-36). RESULTS GLP-1(7-36) inhibited glucagon secretion in isolated islets with an IC50 of 2.5 pmol/l. The effect was particularly strong at low glucose concentrations. The degradation product GLP-1(9-36) shared this capacity. GLP-1(9-36) retained its glucagonostatic effects after genetic/pharmacological inactivation of the GLP-1 receptor. GLP-1(9-36) also potently inhibited glucagon secretion evoked by β-adrenergic stimulation, amino acids and membrane depolarisation. In islet alpha cells, GLP-1(9-36) led to inhibition of Ca2+ entry via voltage-gated Ca2+ channels sensitive to ω-agatoxin, with consequential pertussis-toxin-sensitive depletion of the docked pool of secretory granules, effects that were prevented by the glucagon receptor antagonists REMD2.59 and L-168049. The capacity of GLP-1(9-36) to inhibit glucagon secretion and reduce the number of docked granules was lost in alpha cells from human donors with type 2 diabetes. In vivo, high exogenous concentrations of GLP-1(9-36) (>100 pmol/l) resulted in a small (30%) lowering of circulating glucagon during insulin-induced hypoglycaemia. This effect was abolished by REMD2.59, which promptly increased circulating glucagon by >225% (adjusted for the change in plasma glucose) without affecting pancreatic glucagon content. CONCLUSIONS/INTERPRETATION We conclude that the GLP-1 metabolite GLP-1(9-36) is a systemic inhibitor of glucagon secretion. We propose that the increase in circulating glucagon observed following genetic/pharmacological inactivation of glucagon signalling in mice and in people with type 2 diabetes reflects the removal of GLP-1(9-36)'s glucagonostatic action.
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Affiliation(s)
- Nikhil R Gandasi
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
- Cell Metabolism Lab (GA-08), Department of Developmental Biology and Genetics, Indian Institute of Science, Bangalore, India
| | - Rui Gao
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Lakshmi Kothegala
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
| | - Abigail Pearce
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Cristiano Santos
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
| | - Samuel Acreman
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Davide Basco
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Anna Benrick
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
| | - Margarita V Chibalina
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Anne Clark
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Claudia Guida
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Matthew Harris
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Paul R V Johnson
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford, UK
- Biomedical Research Centre, Oxford National Institute for Health Research, Churchill Hospital, Oxford, UK
| | - Jakob G Knudsen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jinfang Ma
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Caroline Miranda
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Makoto Shigeto
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Andrei I Tarasov
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK
| | - Ho Yan Yeung
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Ingrid W Asterholm
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
| | - Quan Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Reshma Ramracheya
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Graham Ladds
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Patrik Rorsman
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden.
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK.
- Biomedical Research Centre, Oxford National Institute for Health Research, Churchill Hospital, Oxford, UK.
- School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK.
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Sicinski K, Montanari V, Raman VS, Doyle JR, Harwood BN, Song YC, Fagan MP, Rios M, Haines DR, Kopin AS, Beinborn M, Kumar K. A Non-Perturbative Molecular Grafting Strategy for Stable and Potent Therapeutic Peptide Ligands. ACS Cent Sci 2021; 7:454-466. [PMID: 33791428 PMCID: PMC8006168 DOI: 10.1021/acscentsci.0c01237] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Indexed: 06/12/2023]
Abstract
The gut-derived incretin hormone, glucagon-like peptide-1 (GLP1), plays an important physiological role in attenuating post-prandial blood glucose excursions in part by amplifying pancreatic insulin secretion. Native GLP1 is rapidly degraded by the serine protease, dipeptidyl peptidase-4 (DPP4); however, enzyme-resistant analogues of this 30-amino-acid peptide provide an effective therapy for type 2 diabetes (T2D) and can curb obesity via complementary functions in the brain. In addition to its medical relevance, the incretin system provides a fertile arena for exploring how to better separate agonist function at cognate receptors versus susceptibility of peptides to DPP4-induced degradation. We have discovered that novel chemical decorations can make GLP1 and its analogues completely DPP4 resistant while fully preserving GLP1 receptor activity. This strategy is also applicable to other therapeutic ligands, namely, glucose-dependent insulinotropic polypeptide (GIP), glucagon, and glucagon-like peptide-2 (GLP2), targeting the secretin family of receptors. The versatility of the approach offers hundreds of active compounds based on any template that target these receptors. These observations should allow for rapid optimization of pharmacological properties and because the appendages are in a position crucial to receptor stimulation, they proffer the possibility of conferring "biased" signaling and in turn minimizing side effects.
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Affiliation(s)
- Kathleen
M. Sicinski
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Vittorio Montanari
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Venkata S. Raman
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Jamie R. Doyle
- Molecular
Cardiology Research Institute, Tufts Medical
Center, Boston, Massachusetts 02111, United States
| | - Benjamin N. Harwood
- Molecular
Cardiology Research Institute, Tufts Medical
Center, Boston, Massachusetts 02111, United States
| | - Yi Chi Song
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Micaella P. Fagan
- Department
of Neuroscience, Tufts University School
of Medicine, Boston, Massachusetts 02111, United States
| | - Maribel Rios
- Department
of Neuroscience, Tufts University School
of Medicine, Boston, Massachusetts 02111, United States
| | - David R. Haines
- Department of Chemistry, Wellesley College, Wellesley, Massachusetts 02481, United States
| | - Alan S. Kopin
- Molecular
Cardiology Research Institute, Tufts Medical
Center, Boston, Massachusetts 02111, United States
| | - Martin Beinborn
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
- Molecular
Cardiology Research Institute, Tufts Medical
Center, Boston, Massachusetts 02111, United States
| | - Krishna Kumar
- Department
of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
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Ding Y, Ting JP, Liu J, Al-Azzam S, Pandya P, Afshar S. Impact of non-proteinogenic amino acids in the discovery and development of peptide therapeutics. Amino Acids 2020; 52:1207-1226. [PMID: 32945974 PMCID: PMC7544725 DOI: 10.1007/s00726-020-02890-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 09/05/2020] [Indexed: 12/14/2022]
Abstract
With the development of modern chemistry and biology, non-proteinogenic amino acids (NPAAs) have become a powerful tool for developing peptide-based drug candidates. Drug-like properties of peptidic medicines, due to the smaller size and simpler structure compared to large proteins, can be changed fundamentally by introducing NPAAs in its sequence. While peptides composed of natural amino acids can be used as drug candidates, the majority have shown to be less stable in biological conditions. The impact of NPAA incorporation can be extremely beneficial in improving the stability, potency, permeability, and bioavailability of peptide-based therapies. Conversely, undesired effects such as toxicity or immunogenicity should also be considered. The impact of NPAAs in the development of peptide-based therapeutics is reviewed in this article. Further, numerous examples of peptides containing NPAAs are presented to highlight the ongoing development in peptide-based therapeutics.
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Affiliation(s)
- Yun Ding
- Protein Engineering, Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA, 92121, USA
| | - Joey Paolo Ting
- Protein Engineering, Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA, 92121, USA
| | - Jinsha Liu
- Protein Engineering, Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA, 92121, USA
| | - Shams Al-Azzam
- Professional Scientific Services, Eurofins Lancaster Laboratories, Lancaster, PA, 17605, USA
| | - Priyanka Pandya
- Protein Engineering, Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA, 92121, USA
| | - Sepideh Afshar
- Protein Engineering, Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA, 92121, USA.
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Zhong X, Chen Z, Chen Q, Zhao W, Chen Z. Novel Site-Specific Fatty Chain-Modified GLP-1 Receptor Agonist with Potent Antidiabetic Effects. Molecules 2019; 24:molecules24040779. [PMID: 30795583 PMCID: PMC6412877 DOI: 10.3390/molecules24040779] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/15/2019] [Accepted: 02/15/2019] [Indexed: 11/30/2022] Open
Abstract
Glucagon-like peptide-1 receptor (GLP-1R) agonists have emerged as treatment options for type 2 diabetes mellitus (T2DM). Here, we designed a high-throughput GLP-1R extracellular domain (ECD)-based system that enabled the screening of high-potency receptor-biased GLP-1R agonists demonstrating new pharmacological virtues. Firstly, six 12-mer peptides (termed PEP01–06), screened from a large phage displayed peptide library were fused to the N-terminus of Exendin-4 (29–39) to generate PEP07–12. By the use of four lysine-altered PEP07 (PEP13–16) as the starting point, a series of fatty chain conjugates (PEP17–20) were synthesized and evaluated by in vitro GLP-1R-based cell assays. In addition, the acute and long-term in vivo effects on diet-induced obesity (DIO) mice were further evaluated. All four conjugates showed good receptor activation efficacy, and PEP20 was selected to undergo further assessment. Preclinical experiments in DIO mice demonstrated that PEP20 had significant insulinotropic activities and glucose-lowering abilities. Moreover, a prolonged antidiabetic effect of PEP20 was also observed by the hypoglycemic test in DIO mice. Furthermore, long-term treatment with PEP20 achieved beneficial effects on the food intake, weight gain, hemoglobin A1C (HbA1C) lowering activity, and glucose tolerance compared with the control and was similar to the Liraglutide. In conclusion, PEP20, a GLP-1R ECD-biased agonist, may provide a novel therapeutic approach to T2DM.
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Affiliation(s)
- Xia Zhong
- College of Life Science and Technology, Jinan University, Guangzhou 510000, China.
- Reyoung Biopharmaceuticals Co., Ltd, Suzhou 215000, China.
| | - Zhu Chen
- Reyoung Biopharmaceuticals Co., Ltd, Suzhou 215000, China.
- East China University of Science and Technology, Shanghai 200000, China.
| | - Qiong Chen
- Reyoung Biopharmaceuticals Co., Ltd, Suzhou 215000, China.
| | - Wei Zhao
- Reyoung Biopharmaceuticals Co., Ltd, Suzhou 215000, China.
| | - Zhi Chen
- East China University of Science and Technology, Shanghai 200000, China.
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Könitzer JD, Pramanick S, Pan Q, Augustin R, Bandholtz S, Harriman W, Izquierdo S. Generation of a highly diverse panel of antagonistic chicken monoclonal antibodies against the GIP receptor. MAbs 2017; 9:536-549. [PMID: 28055305 PMCID: PMC5384726 DOI: 10.1080/19420862.2016.1276683] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Raising functional antibodies against G protein-coupled receptors (GPCRs) is challenging due to their low density expression, instability in the absence of the cell membrane's lipid bilayer and frequently short extracellular domains that can serve as antigens. In addition, a particular therapeutic concept may require an antibody to not just bind the receptor, but also act as a functional receptor agonist or antagonist. Antagonizing the glucose-dependent insulinotropic polypeptide (GIP) receptor may open up new therapeutic modalities in the treatment of diabetes and obesity. As such, a panel of monoclonal antagonistic antibodies would be a useful tool for in vitro and in vivo proof of concept studies. The receptor is highly conserved between rodents and humans, which has contributed to previous mouse and rat immunization campaigns generating very few usable antibodies. Switching the immunization host to chicken, which is phylogenetically distant from mammals, enabled the generation of a large and diverse panel of monoclonal antibodies containing 172 unique sequences. Three-quarters of all chicken-derived antibodies were functional antagonists, exhibited high-affinities to the receptor extracellular domain and sampled a broad epitope repertoire. For difficult targets, including GPCRs such as GIPR, chickens are emerging as valuable immunization hosts for therapeutic antibody discovery.
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Affiliation(s)
- Jennifer D Könitzer
- a Division Research , Immune Modulation & Biotherapeutics Discovery, Boehringer Ingelheim , Biberach/Riss , Germany
| | | | - Qi Pan
- c Division Research , Immune Modulation & Biotherapeutics Discovery, Boehringer Ingelheim , Ridgefield , CT , USA
| | | | - Sebastian Bandholtz
- e Division Research Germany , Cardio-Metabolic Diseases Research, Boehringer Ingelheim , Biberach/Riss , Germany
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Tsend-Ayush E, He C, Myers MA, Andrikopoulos S, Wong N, Sexton PM, Wootten D, Forbes BE, Grutzner F. Monotreme glucagon-like peptide-1 in venom and gut: one gene - two very different functions. Sci Rep 2016; 6:37744. [PMID: 27898108 PMCID: PMC5127184 DOI: 10.1038/srep37744] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 11/01/2016] [Indexed: 12/11/2022] Open
Abstract
The importance of Glucagon like peptide 1 (GLP-1) for metabolic control and insulin release sparked the evolution of genes mimicking GLP-1 action in venomous species (e.g. Exendin-4 in Heloderma suspectum (gila monster)). We discovered that platypus and echidna express a single GLP-1 peptide in both intestine and venom. Specific changes in GLP-1 of monotreme mammals result in resistance to DPP-4 cleavage which is also observed in the GLP-1 like Exendin-4 expressed in Heloderma venom. Remarkably we discovered that monotremes evolved an alternative mechanism to degrade GLP-1. We also show that monotreme GLP-1 stimulates insulin release in cultured rodent islets, but surprisingly shows low receptor affinity and bias toward Erk signaling. We propose that these changes in monotreme GLP-1 are the result of conflicting function of this peptide in metabolic control and venom. This evolutionary path is fundamentally different from the generally accepted idea that conflicting functions in a single gene favour duplication and diversification, as is the case for Exendin-4 in gila monster. This provides novel insight into the remarkably different metabolic control mechanism and venom function in monotremes and an unique example of how different selective pressures act upon a single gene in the absence of gene duplication.
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Affiliation(s)
- Enkhjargal Tsend-Ayush
- Robinson Research Institute, School of Biological Sciences, The University of Adelaide, South Australia, 5000, Australia
| | - Chuan He
- Robinson Research Institute, School of Biological Sciences, The University of Adelaide, South Australia, 5000, Australia
| | - Mark A Myers
- School of Applied and Biomedical Sciences, Federation University Australia, Mount Helen, Victoria, 3353, Australia
| | - Sof Andrikopoulos
- Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, Victoria 3084, Australia
| | - Nicole Wong
- Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, Victoria 3084, Australia
| | - Patrick M Sexton
- Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, 3052, Australia
| | - Denise Wootten
- Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, 3052, Australia
| | - Briony E Forbes
- Robinson Research Institute, School of Biological Sciences, The University of Adelaide, South Australia, 5000, Australia.,School of Medicine, Flinders University, Bedford Park, South Australia, 5042, Australia
| | - Frank Grutzner
- Robinson Research Institute, School of Biological Sciences, The University of Adelaide, South Australia, 5000, Australia
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Watkins HA, Au M, Bobby R, Archbold JK, Abdul-Manan N, Moore JM, Middleditch MJ, Williams GM, Brimble MA, Dingley AJ, Hay DL. Identification of key residues involved in adrenomedullin binding to the AM1 receptor. Br J Pharmacol 2014; 169:143-55. [PMID: 23351143 DOI: 10.1111/bph.12118] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 12/11/2012] [Accepted: 01/07/2013] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Adrenomedullin (AM) is a peptide hormone whose receptors are members of the class B GPCR family. They comprise a heteromer between the GPCR, the calcitonin receptor-like receptor and one of the receptor activity-modifying proteins 1-3. AM plays a significant role in angiogenesis and its antagonist fragment AM22-52 can inhibit blood vessel and tumour growth. The mechanism by which AM interacts with its receptors is unknown. EXPERIMENTAL APPROACH We determined the AM22-52 binding epitope for the AM1 receptor extracellular domain using biophysical techniques, heteronuclear magnetic resonance spectroscopy and alanine scanning. KEY RESULTS Chemical shift perturbation experiments located the main binding epitope for AM22-52 at the AM1 receptor to the C-terminal 8 amino acids. Isothermal titration calorimetry of AM22-52 alanine-substituted peptides indicated that Y52, G51 and I47 are essential for AM1 receptor binding and that K46 and P49 and R44 have a smaller role to play. Characterization of these peptides at the full-length AM receptors was assessed in Cos7 cells by cAMP assay. This confirmed the essential role of Y52, G51 and I47 in binding to the AM1 receptor, with their substitution resulting in ≥100-fold reduction in antagonist potency compared with AM22-52 . R44A, K46A, S48A and P49A AM22-52 decreased antagonist potency by approximately 10-fold. CONCLUSIONS AND IMPLICATIONS This study localizes the main binding epitope of AM22-52 to its C-terminal amino acids and distinguishes essential residues involved in this binding. This will inform the development of improved AM receptor antagonists.
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Affiliation(s)
- H A Watkins
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
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Lynch AM, Pathak N, Pathak V, O'Harte FPM, Flatt PR, Irwin N, Gault VA. A novel DPP IV-resistant C-terminally extended glucagon analogue exhibits weight-lowering and diabetes-protective effects in high-fat-fed mice mediated through glucagon and GLP-1 receptor activation. Diabetologia 2014; 57:1927-36. [PMID: 24962667 DOI: 10.1007/s00125-014-3296-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 05/27/2014] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Modification of the structure of glucagon could provide useful compounds for the potential treatment of obesity-related diabetes. METHODS This study evaluated N-acetyl-glucagon, (D-Ser(2))glucagon and an analogue of (D-Ser(2))glucagon with the addition of nine amino acids from the C-terminal of exendin(1-39), namely (D-Ser(2))glucagon-exe. RESULTS All analogues were resistant to dipeptidyl peptidase IV degradation. N-Acetyl-glucagon lacked acute insulinotropic effects in BRIN BD11 cells, whereas (D-Ser(2))glucagon and (D-Ser(2))glucagon-exe evoked significant (p < 0.001) insulin release. (D-Ser(2))glucagon-exe stimulated cAMP production (p < 0.001) in glucagon- and GLP-1-receptor (GLP-1R)-transfected cells but not in glucose-dependent insulinotropic polypeptide-receptor-transfected cells. In normal mice, N-acetyl-glucagon and (D-Ser(2))glucagon retained glucagon-like effects of increasing (p < 0.001) plasma glucose and insulin levels. (D-Ser(2))glucagon-exe was devoid of hyperglycaemic actions but substantially (p < 0.001) increased plasma insulin levels. (D-Ser(2))glucagon-exe reduced the glycaemic excursion (p < 0.01) and increased the insulin secretory (p < 0.01) response following a glucose challenge 12 h after administration. Studies in GLP-1R knockout mice confirmed involvement of the GLP-1R pathway in the biological actions of (D-Ser(2))glucagon-exe. Twice-daily administration of (D-Ser(2))glucagon-exe to high-fat-fed mice for 28 days significantly (p < 0.05 to p < 0.001) reduced body weight, energy intake and non-fasting glucose levels, as well as increasing insulin concentrations. Glucose tolerance and insulin sensitivity were significantly (p < 0.01) improved and energy expenditure, O2 consumption and locomotor activity were (p < 0.05 to p < 0.001) augmented. The metabolic benefits were accompanied by increases in pancreatic islet number (p < 0.001) and area (p < 0.05), as well as beta cell area (p < 0.05). Beneficial effects were largely retained for 14 days following cessation of treatment. CONCLUSIONS/INTERPRETATION This study emphasises the potential of (D-Ser(2))glucagon-exe for the treatment of obesity-related diabetes.
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Affiliation(s)
- Aisling M Lynch
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, UK
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Wu L, Zhai Y, Lu J, Wang Q, Sun F. Expression, purification and preliminary characterization of glucagon receptor extracellular domain. Protein Expr Purif 2013; 89:232-40. [DOI: 10.1016/j.pep.2013.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Revised: 04/05/2013] [Accepted: 04/06/2013] [Indexed: 12/13/2022]
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