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Peart LA, Draper M, Tarasov AI. The impact of GLP-1 signalling on the energy metabolism of pancreatic islet β-cells and extrapancreatic tissues. Peptides 2024; 178:171243. [PMID: 38788902 DOI: 10.1016/j.peptides.2024.171243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 05/19/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024]
Abstract
Glucagon-like peptide-1 signalling impacts glucose homeostasis and appetite thereby indirectly affecting substrate availability at the whole-body level. The incretin canonically produces an insulinotropic effect, thereby lowering blood glucose levels by promoting the uptake and inhibiting the production of the sugar by peripheral tissues. Likewise, GLP-1 signalling within the central nervous system reduces the appetite and food intake, whereas its gastric effect delays the absorption of nutrients, thus improving glycaemic control and reducing the risk of postprandial hyperglycaemia. We review the molecular aspects of the GLP-1 signalling, focusing on its impact on intracellular energy metabolism. Whilst the incretin exerts its effects predominantly via a Gs receptor, which decodes the incretin signal into the elevation of intracellular cAMP levels, the downstream signalling cascades within the cell, acting on fast and slow timescales, resulting in an enhancement or an attenuation of glucose catabolism, respectively.
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Affiliation(s)
- Leah A Peart
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Northern Ireland BT52 1SA, UK
| | - Matthew Draper
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Northern Ireland BT52 1SA, UK
| | - Andrei I Tarasov
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Northern Ireland BT52 1SA, UK.
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2
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Sridhar A, Khan D, Babu G, Irwin N, Gault VA, Flatt PR, Moffett CR. Chronic exposure to incretin metabolites GLP-1(9-36) and GIP(3-42) affect islet morphology and beta cell health in high fat fed mice. Peptides 2024; 178:171254. [PMID: 38815655 DOI: 10.1016/j.peptides.2024.171254] [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: 02/19/2024] [Revised: 04/24/2024] [Accepted: 05/27/2024] [Indexed: 06/01/2024]
Abstract
The incretin hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), are rapidly degraded by dipeptidyl peptidase-4 (DPP-4) to their major circulating metabolites GLP-1(9-36) and GIP(3-42). This study investigates the possible effects of these metabolites, and the equivalent exendin molecule Ex(9-39), on pancreatic islet morphology and constituent alpha and beta cells in high-fat diet (HFD) fed mice. Male Swiss TO-mice (6-8 weeks-old) were maintained on a HFD or normal diet (ND) for 4 months and then received twice-daily subcutaneous injections of GLP-1(9-36), GIP(3-42), Ex(9-39) (25 nmol/kg bw) or saline vehicle (0.9% (w/v) NaCl) over a 60-day period. Metabolic parameters were monitored and excised pancreatic tissues were used for immunohistochemical analysis. Body weight and assessed metabolic indices were not changed by peptide administration. GLP-1(9-36) significantly (p<0.001) increased islet density per mm2 tissue, that was decreased (p<0.05) by HFD. Islet, beta and alpha cell areas were increased (p<0.01) following HFD and subsequently reduced (p<0.01-p<0.001) by GIP(3-42) and Ex(9-39) treatment. While GLP-1(9-36) did not affect islet and beta cell areas in HFD mice, it significantly (p<0.01) decreased alpha cell area. Compared to ND and HFD mice, GIP(3-42) treatment significantly (p<0.05) increased beta cell proliferation. Whilst HFD increased (p<0.001) beta cell apoptosis, this was reduced (p<0.01-p<0.001) by both GLP-1(9-36) and GIP(3-42). These data indicate that the major circulating forms of GLP-1 and GIP, namely GLP-1(9-36) and GIP(3-42) previously considered largely inactive, may directly impact pancreatic morphology, with an important protective effect on beta cell health under conditions of beta cell stress.
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Affiliation(s)
- Ananyaa Sridhar
- Biomedical Sciences Research Institute, Diabetes Research Centre, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK.
| | - Dawood Khan
- Biomedical Sciences Research Institute, Diabetes Research Centre, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Gayathri Babu
- Biomedical Sciences Research Institute, Diabetes Research Centre, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- Biomedical Sciences Research Institute, Diabetes Research Centre, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Victor A Gault
- Biomedical Sciences Research Institute, Diabetes Research Centre, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- Biomedical Sciences Research Institute, Diabetes Research Centre, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Charlotte R Moffett
- Biomedical Sciences Research Institute, Diabetes Research Centre, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
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3
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Diz-Chaves Y, Maastor Z, Spuch C, Lamas JA, González-Matías LC, Mallo F. Glucagon-like peptide 1 receptor activation: anti-inflammatory effects in the brain. Neural Regen Res 2024; 19:1671-1677. [PMID: 38103230 PMCID: PMC10960307 DOI: 10.4103/1673-5374.389626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 09/08/2023] [Accepted: 10/14/2023] [Indexed: 12/18/2023] Open
Abstract
The glucagon-like peptide 1 is a pleiotropic hormone that has potent insulinotropic effects and is key in treating metabolic diseases such as diabetes and obesity. Glucagon-like peptide 1 exerts its effects by activating a membrane receptor identified in many tissues, including different brain regions. Glucagon-like peptide 1 activates several signaling pathways related to neuroprotection, like the support of cell growth/survival, enhancement promotion of synapse formation, autophagy, and inhibition of the secretion of proinflammatory cytokines, microglial activation, and apoptosis during neural morphogenesis. The glial cells, including astrocytes and microglia, maintain metabolic homeostasis and defense against pathogens in the central nervous system. After brain insult, microglia are the first cells to respond, followed by reactive astrocytosis. These activated cells produce proinflammatory mediators like cytokines or chemokines to react to the insult. Furthermore, under these circumstances, microglia can become chronically inflammatory by losing their homeostatic molecular signature and, consequently, their functions during many diseases. Several processes promote the development of neurological disorders and influence their pathological evolution: like the formation of protein aggregates, the accumulation of abnormally modified cellular constituents, the formation and release by injured neurons or synapses of molecules that can dampen neural function, and, of critical importance, the dysregulation of inflammatory control mechanisms. The glucagon-like peptide 1 receptor agonist emerges as a critical tool in treating brain-related inflammatory pathologies, restoring brain cell homeostasis under inflammatory conditions, modulating microglia activity, and decreasing the inflammatory response. This review summarizes recent advances linked to the anti-inflammatory properties of glucagon-like peptide 1 receptor activation in the brain related to multiple sclerosis, Alzheimer's disease, Parkinson's disease, vascular dementia, or chronic migraine.
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Affiliation(s)
- Yolanda Diz-Chaves
- Biomedical Research Centre (CINBIO), Laboratory of Endocrinology, University of Vigo, Galicia Sur Health Research Institute, Vigo, Spain
| | - Zainab Maastor
- Biomedical Research Centre (CINBIO), Laboratory of Endocrinology, University of Vigo, Galicia Sur Health Research Institute, Vigo, Spain
| | - Carlos Spuch
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, CIBERSAM, Hospital Álvaro Cunqueiro, Sala Investigación, Estrada Clara Campoamor, Vigo, Spain
| | - José Antonio Lamas
- Biomedical Research Centre (CINBIO), Laboratory of Neuroscience, University of Vigo, Galicia Sur Health Research Institute, Vigo, Spain
| | - Lucas C. González-Matías
- Biomedical Research Centre (CINBIO), Laboratory of Endocrinology, University of Vigo, Galicia Sur Health Research Institute, Vigo, Spain
| | - Federico Mallo
- Biomedical Research Centre (CINBIO), Laboratory of Endocrinology, University of Vigo, Galicia Sur Health Research Institute, Vigo, Spain
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4
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Helsted MM, Schaltz NL, Gasbjerg LS, Christensen MB, Vilsbøll T, Knop FK. Safety of native glucose-dependent insulinotropic polypeptide in humans. Peptides 2024; 177:171214. [PMID: 38615716 DOI: 10.1016/j.peptides.2024.171214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 04/04/2024] [Accepted: 04/09/2024] [Indexed: 04/16/2024]
Abstract
In this systematic review, we assessed the safety and possible safety events of native glucose-dependent insulinotropic polypeptide (GIP)(1-42) in human studies with administration of synthetic human GIP. We searched the PubMed database for all trials investigating synthetic human GIP(1-42) administration. A total of 67 studies were included. Study duration ranged from 30 min to 6 days. In addition to healthy individuals, the studies included individuals with impaired glucose tolerance, type 2 diabetes, type 1 diabetes, chronic pancreatitis and secondary diabetes, latent autoimmune diabetes in adults, diabetes caused by a mutation in the hepatocyte nuclear factor 1-alpha gene, end-stage renal disease, chronic renal insufficiency, critical illness, hypoparathyroidism, or cystic fibrosis-related diabetes. Of the included studies, 78% did not mention safety events, 10% of the studies reported that no safety events were observed in relation to GIP administration, and 15% of the studies reported safety events in relation to GIP administration with most frequently reported event being a moderate and transient increased heart rate. Gastrointestinal safety events, and changes in blood pressure were also reported. Plasma concentration of active GIP(1-42) increased linearly with dose independent of participant phenotype. There was no significant correlation between achieved maximal concentration of GIP(1-42) and reported safety events. Clearance rates of GIP(1-42) were similar between participant groups. In conclusion, the available data indicate that GIP(1-42) in short-term (up to 6 days) infusion studies is generally well-tolerated. The long-term safety of continuous GIP(1-42) administration is unknown.
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Affiliation(s)
- Mads M Helsted
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Nina L Schaltz
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Lærke S Gasbjerg
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mikkel B Christensen
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Pharmacology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark; Copenhagen Center for Translational Research, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Tina Vilsbøll
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Steno Diabetes Center Copenhagen, Herlev, Denmark
| | - Filip K Knop
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Steno Diabetes Center Copenhagen, Herlev, Denmark.
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5
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Matveyenko A, Vella A. An unclear role for the GLP-1 metabolite GLP-1(9-36) in human islet physiology. Diabetologia 2024; 67:1444-1445. [PMID: 38580845 DOI: 10.1007/s00125-024-06141-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 02/27/2024] [Indexed: 04/07/2024]
Affiliation(s)
- Aleksey Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, MN, USA.
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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] [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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Wang C, Gong B, Zhu Q, Han J, Sun L. Novel GLP-1(28-36) amide-derived hybrid peptide A3 with weight loss and hypoglycemic activities. Eur J Pharmacol 2023; 961:176200. [PMID: 37979828 DOI: 10.1016/j.ejphar.2023.176200] [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: 05/10/2023] [Revised: 11/10/2023] [Accepted: 11/10/2023] [Indexed: 11/20/2023]
Abstract
Glucagon-like peptide-1 (GLP-1) has gained much attention in the last decade for the treatment of type 2 diabetes. Accumulating evidence indicates that some metabolites of GLP-1 have biological activities that might contribute to the pleiotropic effects of GLP-1 independent of the GLP-1 receptor. The hypoglycemic and weight-reducing effects of the reported metabolites and modifications still need to be confirmed. In this study, we started from the C-terminal nonapeptide GLP-1(28-36) amide and developed a series of GLP-1(28-36) amide-derived hybrid peptides. Our findings of biological activity evaluation in INS-1 cells, streptozotocin-induced diabetic and diet-induced obesity mice confirmed a novel hybrid peptide, A3, and provided a new perspective in the development of new drugs from peptide metabolites.
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Affiliation(s)
- Chen Wang
- Department of Pharmaceutics, College of Medicine, Jiaxing University, Jiaxing, Zhejiang, PR China
| | - Binbin Gong
- Department of Pharmaceutics, College of Medicine, Jiaxing University, Jiaxing, Zhejiang, PR China; College of Pharmacy, Zhejiang University of Technology, Hangzhou, 310000, PR China
| | - Qianqian Zhu
- Department of Pharmaceutics, College of Medicine, Jiaxing University, Jiaxing, Zhejiang, PR China
| | - Jing Han
- School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, 221116, PR China
| | - Lidan Sun
- Department of Pharmaceutics, College of Medicine, Jiaxing University, Jiaxing, Zhejiang, PR China.
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8
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Bany Bakar R, Reimann F, Gribble FM. The intestine as an endocrine organ and the role of gut hormones in metabolic regulation. Nat Rev Gastroenterol Hepatol 2023; 20:784-796. [PMID: 37626258 DOI: 10.1038/s41575-023-00830-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/25/2023] [Indexed: 08/27/2023]
Abstract
Gut hormones orchestrate pivotal physiological processes in multiple metabolically active tissues, including the pancreas, liver, adipose tissue, gut and central nervous system, making them attractive therapeutic targets in the treatment of obesity and type 2 diabetes mellitus. Most gut hormones are derived from enteroendocrine cells, but bioactive peptides that are derived from other intestinal epithelial cell types have also been implicated in metabolic regulation and can be considered gut hormones. A deeper understanding of the complex inter-organ crosstalk mediated by the intestinal endocrine system is a prerequisite for designing more effective drugs that are based on or target gut hormones and their receptors, and extending their therapeutic potential beyond obesity and diabetes mellitus. In this Review, we present an overview of gut hormones that are involved in the regulation of metabolism and discuss their action in the gastrointestinal system and beyond.
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Affiliation(s)
- Rula Bany Bakar
- Wellcome Trust-MRC Institute of Metabolic Science Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Frank Reimann
- Wellcome Trust-MRC Institute of Metabolic Science Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Fiona M Gribble
- Wellcome Trust-MRC Institute of Metabolic Science Metabolic Research Laboratories, University of Cambridge, Cambridge, UK.
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9
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Welch AA, Farahani RA, Egan AM, Laurenti MC, Zeini M, Vella M, Bailey KR, Cobelli C, Dalla Man C, Matveyenko A, Vella A. Glucagon-like peptide-1 receptor blockade impairs islet secretion and glucose metabolism in humans. J Clin Invest 2023; 133:e173495. [PMID: 37751301 PMCID: PMC10645389 DOI: 10.1172/jci173495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 09/12/2023] [Indexed: 09/27/2023] Open
Abstract
BACKGROUNDProglucagon can be processed to glucagon-like peptide1 (GLP-1) within the islet, but its contribution to islet function in humans remains unknown. We sought to understand whether pancreatic GLP-1 alters islet function in humans and whether this is affected by type 2 diabetes.METHODSWe therefore studied individuals with and without type 2 diabetes on two occasions in random order. On one occasion, exendin 9-39, a competitive antagonist of the GLP-1 Receptor (GLP1R), was infused, while on the other, saline was infused. The tracer dilution technique ([3-3H] glucose) was used to measure glucose turnover during fasting and during a hyperglycemic clamp.RESULTSExendin 9-39 increased fasting glucose concentrations; fasting islet hormone concentrations were unchanged, but inappropriate for the higher fasting glucose observed. In people with type 2 diabetes, fasting glucagon concentrations were markedly elevated and persisted despite hyperglycemia. This impaired suppression of endogenous glucose production by hyperglycemia.CONCLUSIONThese data show that GLP1R blockade impairs islet function, implying that intra-islet GLP1R activation alters islet responses to glucose and does so to a greater degree in people with type 2 diabetes.TRIAL REGISTRATIONThis study was registered at ClinicalTrials.gov NCT04466618.FUNDINGThe study was primarily funded by NIH NIDDK DK126206. AV is supported by DK78646, DK116231 and DK126206. CDM was supported by MIUR (Italian Minister for Education) under the initiative "Departments of Excellence" (Law 232/2016).
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Affiliation(s)
- Andrew A. Welch
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Rahele A. Farahani
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Aoife M. Egan
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Marcello C. Laurenti
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Maya Zeini
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Max Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Kent R. Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Aleksey Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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10
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Gasbjerg LS, Bari EJ, Christensen M, Knop FK. Exendin(9-39)NH 2 : Recommendations for clinical use based on a systematic literature review. Diabetes Obes Metab 2021; 23:2419-2436. [PMID: 34351033 DOI: 10.1111/dom.14507] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 07/23/2021] [Accepted: 07/28/2021] [Indexed: 12/25/2022]
Abstract
AIM To present an overview of exendin(9-39)NH2 usage as a scientific tool in humans and provide recommendations for dosage and infusion regimes. METHODS We systematically searched the literature on exendin(9-39)NH2 and included for review 44 clinical studies reporting use of exendin(9-39)NH2 in humans. RESULTS Exendin(9-39)NH2 binds to the orthosteric binding site of the glucagon-like peptide-1 (GLP-1) receptor with high affinity. The plasma elimination half-life of exendin(9-39)NH2 after intravenous administration is ~30 minutes, requiring ~2.5 hours of constant infusion before steady-state plasma concentrations can be expected. Studies utilizing infusions with exendin(9-39)NH2 in humans have applied varying regimens (priming with a bolus or constant infusion) and dosages (continuous infusion rate range 30-900 pmol/kg/min) with subsequent differences in effects. Administration of exendin(9-39)NH2 in healthy individuals, patients with diabetes, obese patients, and patients who have undergone bariatric surgery significantly increases fasting and postprandial levels of glucose and glucagon, but has inconsistent effects on circulating concentrations of insulin and C-peptide, gastric emptying, appetite sensations, and food intake. Importantly, exendin(9-39)NH2 induces secretion of all L cell products (ie, in addition to GLP-1, also peptide YY, glucagon-like peptide-2, oxyntomodulin, and glicentin) complicating use of exendin(9-39)NH2 as a tool to study the isolated effect of GLP-1. CONCLUSIONS Exendin(9-39)NH2 is selective for the GLP-1 receptor, with numerous and complex whole-body effects. To obtain GLP-1 receptor blockade in humans, we recommend an initial high-dose infusion, followed by a continuous infusion rate aiming at a ratio of exendin(9-39)NH2 to GLP-1 of 2000:1. Highlights Exendin(9-39)NH2 is a competitive antagonist of the human GLP-1 receptor. Exendin(9-39)NH2 has been used as a tool to delineate human GLP-1 physiology since 1998. Exendin(9-39)NH2 induces secretion of GLP-1 and other L cell products. Reported effects of exendin(9-39)NH2 on insulin levels and food intake are inconsistent. Here, we provide recommendations for the use of exendin(9-39)NH2 in clinical studies.
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Affiliation(s)
- Laerke Smidt Gasbjerg
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emilie Johanning Bari
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Mikkel Christensen
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- Department of Clinical Pharmacology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
- Copenhagen Center for Translational Research, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Filip Krag Knop
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Centre for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Centre Copenhagen, Gentofte, Denmark
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11
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Li Y, Glotfelty EJ, Karlsson T, Fortuno LV, Harvey BK, Greig NH. The metabolite GLP-1 (9-36) is neuroprotective and anti-inflammatory in cellular models of neurodegeneration. J Neurochem 2021; 159:867-886. [PMID: 34569615 DOI: 10.1111/jnc.15521] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 09/17/2021] [Accepted: 09/22/2021] [Indexed: 12/23/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) is best known for its insulinotropic action following food intake. Its metabolite, GLP-1 (9-36), was assumed biologically inactive because of low GLP-1 receptor (GLP-1R) affinity and non-insulinotropic properties; however, recent studies contradict this assumption. Increased use of FDA approved GLP-1 analogues for treating metabolic disorders and neurodegenerative diseases raises interest in GLP-1 (9-36)'s biological role. We use human SH-SY5Y neuroblastoma cells and a GLP-1R over-expressing variety (#9), in both undifferentiated and differentiated states, to evaluate the neurotrophic/neuroprotective effects of GLP-1 (9-36) against toxic glutamate exposure and other oxidative stress models (via the MTS, LDH or ROS assays). In addition, we examine GLP-1 (9-36)'s signaling pathways, including cyclic-adenosine monophosphate (cAMP), protein kinase-A (PKA), and 5' adenosine monophosphate-activated protein kinase (AMPK) via the use of ELISA, pharmacological inhibitors, or GLP-1R antagonist. Human HMC3 and mouse IMG microglial cell lines were used to study the anti-inflammatory effects of GLP-1 (9-36) against lipopolysaccharide (LPS) (via ELISA). Finally, we applied GLP-1 (9-36) to primary dissociation cultures challenged with α-synuclein or amyloid-β and assessed survival and morphology via immunochemistry. We demonstrate evidence of GLP-1R, cAMP, PKA, and AMPK-mediated neurotrophic and neuroprotective effects of GLP-1 (9-36). The metabolite significantly reduced IL-6 and TNF-α levels in HMC3 and IMG microglial cells, respectively. Lastly, we show mild but significant effects of GLP-1 (9-36) in primary neuron cultures challenged with α-synuclein or amyloid-β. These studies enhance understanding of GLP-1 (9-36)'s effects on the nervous system and its potential as a primary or complementary treatment in pathological contexts.
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Affiliation(s)
- Yazhou Li
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Elliot J Glotfelty
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA.,Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Tobias Karlsson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Lowella V Fortuno
- Molecular Mechanisms of Cellular Stress and Inflammation Unit, Integrative Neuroscience Department, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Brandon K Harvey
- Molecular Mechanisms of Cellular Stress and Inflammation Unit, Integrative Neuroscience Department, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Nigel H Greig
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
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12
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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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13
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Cao C, Wei S, Xu X, Song S, Lai Y, Li J. Signal Peptide Optimization to Prevent N-terminal Truncation of Glucagon Like Peptide-1/IgG-Fc Fusion Protein. Int J Pept Res Ther 2020. [DOI: 10.1007/s10989-020-10112-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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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: 862] [Impact Index Per Article: 172.4] [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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15
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Makrilakis K. The Role of DPP-4 Inhibitors in the Treatment Algorithm of Type 2 Diabetes Mellitus: When to Select, What to Expect. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16152720. [PMID: 31366085 PMCID: PMC6696077 DOI: 10.3390/ijerph16152720] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 07/26/2019] [Accepted: 07/26/2019] [Indexed: 12/12/2022]
Abstract
Type 2 diabetes mellitus is a growing global public health problem, the prevalence of which is projected to increase in the succeeding decades. It is potentially associated with many complications, affecting multiple organs and causing a huge burden to the society. Due to its multi-factorial pathophysiology, its treatment is varied and based upon a multitude of pharmacologic agents aiming to tackle the many aspects of the disease pathophysiology (increasing insulin availability [either through direct insulin administration or through agents that promote insulin secretion], improving sensitivity to insulin, delaying the delivery and absorption of carbohydrates from the gastrointestinal tract, or increasing urinary glucose excretion). DPP-4 (dipeptidyl peptidase-4) inhibitors (or “gliptins”) represent a class of oral anti-hyperglycemic agents that inhibit the enzyme DPP-4, thus augmenting the biological activity of the “incretin” hormones (glucagon-like peptide-1 [GLP-1] and glucose-dependent insulinotropic polypeptide [GIP]) and restoring many of the pathophysiological problems of diabetes. They have already been used over more than a decade in the treatment of the disease. The current manuscript will review the mechanism of action, therapeutic utility, and the role of DPP-4 inhibitors for the treatment of type 2 diabetes mellitus.
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Affiliation(s)
- Konstantinos Makrilakis
- National and Kapodistrian University of Athens Medical School, Laiko General Hospital, 17 Ag. Thoma St., 11527 Athens, Greece.
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16
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Li L, Wu L, E X, Yan W, Cai X, Han J, Sun L. Novel nonapeptide GLP (28-36) amide derivatives with improved hypoglycemic and body weight lowering effects. Bioorg Med Chem 2019; 27:1670-1676. [PMID: 30878191 DOI: 10.1016/j.bmc.2019.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/06/2019] [Accepted: 03/06/2019] [Indexed: 11/25/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) has emerged as a major therapeutic target for the treatment of type 2 diabetes. The nonapeptide GLP-1 (28-36) amide is one of the biological C-terminal products of GLP-1 modified by the neutral endopeptidase (NEP) 24.11 with limited hypoglycemic activity. In this study, we focused on the modification of GLP-1 (28-36) amide for the first time and synthesized a series of GLP-1 (28-36) amide analogues. Results of biological activity evaluation in INS-1 cell, STZ-induced diabetic and diet induced obesity (DIO) mice indicated that S3 as a promising candidate to treat type 2 diabetes and obesity.
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Affiliation(s)
- Leyao Li
- Integrated Medicine Research Center for Neurological Rehabilitation, College of Medicine, Jiaxing University, Jiaxing 314001, PR China
| | - Lingling Wu
- Integrated Medicine Research Center for Neurological Rehabilitation, College of Medicine, Jiaxing University, Jiaxing 314001, PR China
| | - Xia E
- Integrated Medicine Research Center for Neurological Rehabilitation, College of Medicine, Jiaxing University, Jiaxing 314001, PR China
| | - Wenru Yan
- Integrated Medicine Research Center for Neurological Rehabilitation, College of Medicine, Jiaxing University, Jiaxing 314001, PR China
| | - Xingguang Cai
- Center of Drug Discovery, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, PR China
| | - Jing Han
- School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou 221116, PR China
| | - Lidan Sun
- Integrated Medicine Research Center for Neurological Rehabilitation, College of Medicine, Jiaxing University, Jiaxing 314001, PR China.
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17
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Ramírez E, Picatoste B, González-Bris A, Oteo M, Cruz F, Caro-Vadillo A, Egido J, Tuñón J, Morcillo MA, Lorenzo Ó. Sitagliptin improved glucose assimilation in detriment of fatty-acid utilization in experimental type-II diabetes: role of GLP-1 isoforms in Glut4 receptor trafficking. Cardiovasc Diabetol 2018; 17:12. [PMID: 29325553 PMCID: PMC5765634 DOI: 10.1186/s12933-017-0643-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/12/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The distribution of glucose and fatty-acid transporters in the heart is crucial for energy consecution and myocardial function. In this sense, the glucagon-like peptide-1 (GLP-1) enhancer, sitagliptin, improves glucose homeostasis but it could also trigger direct cardioprotective actions, including regulation of energy substrate utilization. METHODS Type-II diabetic GK (Goto-Kakizaki), sitagliptin-treated GK (10 mg/kg/day) and wistar rats (n = 10, each) underwent echocardiographic evaluation, and positron emission tomography scanning for [18F]-2-fluoro-2-deoxy-D-glucose (18FDG). Hearts and plasma were isolated for biochemical approaches. Cultured cardiomyocytes were examined for receptor distribution after incretin stimulation in high fatty acid or high glucose media. RESULTS Untreated GK rats exhibited hyperglycemia, hyperlipidemia, insulin resistance, and plasma GLP-1 reduction. Moreover, GK myocardium decreased 18FDG assimilation and diastolic dysfunction. However, sitagliptin improved hyperglycemia, insulin resistance, and GLP-1 levels, and additionally, enhanced 18FDG uptake and diastolic function. Sitagliptin also stimulated the sarcolemmal translocation of the glucose transporter-4 (Glut4), in detriment of the fatty acyl translocase (FAT)/CD36. In fact, Glut4 mRNA expression and sarcolemmal translocation were also increased after GLP-1 stimulation in high-fatty acid incubated cardiomyocytes. PI3K/Akt and AMPKα were involved in this response. Intriguingly, the GLP-1 degradation metabolite, GLP-1(9-36), showed similar effects. CONCLUSIONS Besides of its anti-hyperglycemic effect, sitagliptin-enhanced GLP-1 may ameliorate diastolic dysfunction in type-II diabetes by shifting fatty acid to glucose utilization in the cardiomyocyte, and thus, improving cardiac efficiency and reducing lipolysis.
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Affiliation(s)
- E Ramírez
- Renal, Vascular and Diabetes Laboratory, Instituto de Investigaciones Sanitarias-Fundación Jiménez Díaz, School of Medicine, Universidad Autónoma, Av. Reyes Católicos 2, 28040, Madrid, Spain
| | - B Picatoste
- Renal, Vascular and Diabetes Laboratory, Instituto de Investigaciones Sanitarias-Fundación Jiménez Díaz, School of Medicine, Universidad Autónoma, Av. Reyes Católicos 2, 28040, Madrid, Spain
| | - A González-Bris
- Renal, Vascular and Diabetes Laboratory, Instituto de Investigaciones Sanitarias-Fundación Jiménez Díaz, School of Medicine, Universidad Autónoma, Av. Reyes Católicos 2, 28040, Madrid, Spain
| | - M Oteo
- Biomedical Applications of Radioisotopes and Pharmacokinetics, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
| | - F Cruz
- Biomedical Applications of Radioisotopes and Pharmacokinetics, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
| | - A Caro-Vadillo
- Veterinary School, Universidad Complutense, Madrid, Spain
| | - J Egido
- Renal, Vascular and Diabetes Laboratory, Instituto de Investigaciones Sanitarias-Fundación Jiménez Díaz, School of Medicine, Universidad Autónoma, Av. Reyes Católicos 2, 28040, Madrid, Spain.,Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM) Network, Madrid, Spain
| | - J Tuñón
- Department of Cardiology, Hospital Fundación Jiménez Díaz, Madrid, Spain
| | - M A Morcillo
- Biomedical Applications of Radioisotopes and Pharmacokinetics, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
| | - Ó Lorenzo
- Renal, Vascular and Diabetes Laboratory, Instituto de Investigaciones Sanitarias-Fundación Jiménez Díaz, School of Medicine, Universidad Autónoma, Av. Reyes Católicos 2, 28040, Madrid, Spain. .,Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM) Network, Madrid, Spain.
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18
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Gao H, Zhao Q, Song Z, Yang Z, Wu Y, Tang S, Alahdal M, Zhang Y, Jin L. PGLP‐1, a novel long‐acting dual‐function GLP‐1 analog, ameliorates streptozotocin‐induced hyperglycemia and inhibits body weight loss. FASEB J 2017; 31:3527-3539. [DOI: 10.1096/fj.201700002r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 04/11/2017] [Indexed: 12/28/2022]
Affiliation(s)
- Huashan Gao
- State Key Laboratory of Natural MedicinesJiangsu Key Laboratory of Drug ScreeningSchool of Life Science and TechnologyChina Pharmaceutical University Nanjing China
- College of Chemistry and Chemical EngineeringPingdingshan University Pingdingshan China
| | - Qian Zhao
- State Key Laboratory of Natural MedicinesJiangsu Key Laboratory of Drug ScreeningSchool of Life Science and TechnologyChina Pharmaceutical University Nanjing China
| | - Ziwei Song
- State Key Laboratory of Natural MedicinesJiangsu Key Laboratory of Drug ScreeningSchool of Life Science and TechnologyChina Pharmaceutical University Nanjing China
| | - Zhaocong Yang
- State Key Laboratory of Natural MedicinesJiangsu Key Laboratory of Drug ScreeningSchool of Life Science and TechnologyChina Pharmaceutical University Nanjing China
| | - You Wu
- State Key Laboratory of Natural MedicinesJiangsu Key Laboratory of Drug ScreeningSchool of Life Science and TechnologyChina Pharmaceutical University Nanjing China
| | - Shanshan Tang
- State Key Laboratory of Natural MedicinesJiangsu Key Laboratory of Drug ScreeningSchool of Life Science and TechnologyChina Pharmaceutical University Nanjing China
| | - Murad Alahdal
- State Key Laboratory of Natural MedicinesJiangsu Key Laboratory of Drug ScreeningSchool of Life Science and TechnologyChina Pharmaceutical University Nanjing China
| | - Yanfeng Zhang
- State Key Laboratory of Natural MedicinesJiangsu Key Laboratory of Drug ScreeningSchool of Life Science and TechnologyChina Pharmaceutical University Nanjing China
| | - Liang Jin
- State Key Laboratory of Natural MedicinesJiangsu Key Laboratory of Drug ScreeningSchool of Life Science and TechnologyChina Pharmaceutical University Nanjing China
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19
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Gorski JN, Pachanski MJ, Mane J, Plummer CW, Souza S, Thomas-Fowlkes BS, Ogawa AM, Weinglass AB, Di Salvo J, Cheewatrakoolpong B, Howard AD, Colletti SL, Trujillo ME. GPR40 reduces food intake and body weight through GLP-1. Am J Physiol Endocrinol Metab 2017; 313:E37-E47. [PMID: 28292762 DOI: 10.1152/ajpendo.00435.2016] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/09/2017] [Accepted: 03/01/2017] [Indexed: 12/15/2022]
Abstract
G protein-coupled receptor 40 (GPR40) partial agonists lower glucose through the potentiation of glucose-stimulated insulin secretion, which is believed to provide significant glucose lowering without the weight gain or hypoglycemic risk associated with exogenous insulin or glucose-independent insulin secretagogues. The class of small-molecule GPR40 modulators, known as AgoPAMs (agonist also capable of acting as positive allosteric modulators), differentiate from partial agonists, binding to a distinct site and functioning as full agonists to stimulate the secretion of both insulin and glucagon-like peptide-1 (GLP-1). Here we show that GPR40 AgoPAMs significantly increase active GLP-1 levels and reduce acute and chronic food intake and body weight in diet-induced obese (DIO) mice. These effects of AgoPAM treatment on food intake are novel and required both GPR40 and GLP-1 receptor signaling pathways, as demonstrated in GPR40 and GLP-1 receptor-null mice. Furthermore, weight loss associated with GPR40 AgoPAMs was accompanied by a significant reduction in gastric motility in these DIO mice. Chronic treatment with a GPR40 AgoPAM, in combination with a dipeptidyl peptidase IV inhibitor, synergistically decreased food intake and body weight in the mouse. The effect of GPR40 AgoPAMs on GLP-1 secretion was recapitulated in lean, healthy rhesus macaque demonstrating that the putative mechanism mediating weight loss translates to higher species. Together, our data indicate effects of AgoPAMs that go beyond glucose lowering previously observed with GPR40 partial agonist treatment with additional potential for weight loss.
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Affiliation(s)
- Judith N Gorski
- Department of In Vivo Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey
| | - Michele J Pachanski
- Department of In Vivo Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey
| | - Joel Mane
- Department of In Vivo Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey
| | - Christopher W Plummer
- Department of Medicinal Chemistry, Merck Research Laboratories, Kenilworth, New Jersey
| | - Sarah Souza
- Department of In Vitro Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey; and
| | - Brande S Thomas-Fowlkes
- Department of In Vitro Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey; and
| | - Aimie M Ogawa
- Department of In Vitro Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey; and
| | - Adam B Weinglass
- Department of In Vitro Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey; and
| | - Jerry Di Salvo
- Department of In Vitro Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey; and
| | | | - Andrew D Howard
- Department of Cardiometabolic Diseases, Merck Research Laboratories, Kenilworth, New Jersey
| | - Steven L Colletti
- Department of Medicinal Chemistry, Merck Research Laboratories, Kenilworth, New Jersey
| | - Maria E Trujillo
- Department of In Vivo Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey;
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20
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GLP-1 receptor independent pathways: emerging beneficial effects of GLP-1 breakdown products. Eat Weight Disord 2017; 22:231-240. [PMID: 28040864 DOI: 10.1007/s40519-016-0352-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 12/15/2016] [Indexed: 12/26/2022] Open
Abstract
The glucagon-like peptide-1 (GLP-1) axis has emerged as a major therapeutic target for the treatment of type 2 diabetes and, recently, of obesity. The insulinotropic activity of the native incretin hormone GLP-1(7-36)amide, which is mainly exerted through a unique G protein-coupled receptor (GLP-1R), is terminated via enzymatic cleavage by dipeptidyl peptidase-IV that generates a C-terminal GLP-1 metabolite GLP-1(9-36)amide, the major circulating form in plasma. GLP-1(28-36)amide and GLP-1(32-36)amide are further cleavage products derived from GLP-1(7-36)amide and GLP-1(9-36)amide by the action of a neutral endopeptidase known as neprilysin. Until recently, GLP-1-derived metabolites were generally considered metabolically inactive. However, emerging evidence indicates that GLP-1 byproducts have insulinomimetic activities that may contribute to the pleiotropic effects of GLP-1 independently of the canonical GLP-1R. The recent studies reporting the beneficial effects of the administration of these metabolites in vivo and in vitro are the focus of this review. Collectively, these results suggest that GLP-1 metabolites inhibit hepatic glucose production, exert antioxidant cardio- and neuroprotective actions, reduce oxidative stress in vasculature and have both anti-apoptotic and proliferative effects in pancreatic β-cells, putatively by the modulation of mitochondrial functions. These findings have implication in energy homeostasis, obesity and its associated metabolic and cardiovascular complications as well as incretin-based therapies for the treatment of diabetes and obesity.
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21
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Lindqvist A, Ekelund M, Pierzynowski S, Groop L, Hedenbro J, Wierup N. Gastric bypass in the pig increases GIP levels and decreases active GLP-1 levels. Peptides 2017; 90:78-82. [PMID: 28242256 DOI: 10.1016/j.peptides.2017.02.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 02/17/2017] [Accepted: 02/21/2017] [Indexed: 01/06/2023]
Abstract
Gastric bypass surgery results in remission of type 2 diabetes in the majority of patients. The incretin hormones glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) have been implicated in the observed remission. Most knowledge so far has been generated in obese subjects. To isolate the surgical effects of gastric bypass on metabolism and hormone responses from the confounding influence of obesity, T2D, or food intake, we performed gastric bypass in lean pigs, using sham-operated and pair-fed pigs as controls. Thus, pigs were subjected to Roux-en-Y gastric bypass (RYGB) or sham surgery and oral glucose tolerance tests (OGTT). RYGB pigs and sham pigs exhibited similar basal and 120-min glucose levels in response to the OGTT. However, RYGB pigs had approximately 1.6-fold higher 30-min glucose (p<0.01). Early insulin release (EIR) was enhanced approximately 3.5-fold in the RYGB pigs (p<0.01). Furthermore, GIP release, both acute and sustained release (p<0.001 and p<0.01, respectively), was increased approximately 2.5-fold and 1.4-fold, respectively, in RYGB pigs. Although total GLP-1 release increased approximately 2.1-fold after RYGB (p<0.001), active GLP-1 was 33% lower (p<0.01). Interestingly basal DPP4-activity was approximately 3.2-fold higher in RYGB pigs (p<0.001). In conclusion, RYGB in lean pigs increases the response of GIP, total GLP-1, and insulin, but reduces levels of active GLP-1 in response to an oral glucose load. These data challenge the role of active GLP-1 as a contributor to remission from diabetes after RYGB.
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Affiliation(s)
| | | | | | - Leif Groop
- Lund University Diabetes Centre, Malmö, Sweden
| | - Jan Hedenbro
- Department of Surgery, Lund University, Lund, Sweden
| | - Nils Wierup
- Lund University Diabetes Centre, Malmö, Sweden.
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22
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Li J, Zheng J, Wang S, Lau HK, Fathi A, Wang Q. Cardiovascular Benefits of Native GLP-1 and its Metabolites: An Indicator for GLP-1-Therapy Strategies. Front Physiol 2017; 8:15. [PMID: 28194113 PMCID: PMC5276855 DOI: 10.3389/fphys.2017.00015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 01/09/2017] [Indexed: 12/23/2022] Open
Abstract
Cardiovascular disease is a common co-morbidity and leading cause of death in patients with type 2 diabetes mellitus (T2DM). Glucagon-like peptide 1 (GLP-1) is a peptide hormone produced by intestinal L cells in response to feeding. Native GLP-1 (7-36) amide is rapidly degraded by diaminopeptidyl peptidase-4 (DPP4) to GLP-1 (9-36) amide, making 9-36a the major circulating form. While it is 7-36a, and not its metabolites, which exerts trophic effects on islet β-cells, recent studies suggest that both 7-36a and its metabolites have direct cardiovascular effects, including preserving cardiomyocyte viability, ameliorating cardiac function, and vasodilation. In particular, the difference in cardiovascular effects between 7-36a and 9-36a is attracting attention. Growing evidence has strengthened the presumption that their cardiovascular effects are overlapping, but distinct and complementary to each other; 7-36a exerts cardiovascular effects in a GLP-1 receptor (GLP-1R) dependent pathway, whereas 9-36a does so in a GLP-1R independent pathway. GLP-1 therapies have been developed using two main strategies: DPP4-resistant GLP-1 analogs/GLP-1R agonists and DPP4 inhibitors, which both aim to prolong the life-time of circulating 7-36a. One prominent concern that should be addressed is that the cardiovascular benefits of 9-36a are lacking in these strategies. This review attempts to differentiate the cardiovascular effects between 7-36a and 9-36a in order to provide new insights into GLP-1 physiology, and facilitate our efforts to develop a superior GLP-1-therapy strategy for T2DM and cardiovascular diseases.
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Affiliation(s)
- Junfeng Li
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical College, Fudan UniversityShanghai, China; Department of Endocrinology, Renmin Hospital of Wuhan UniversityWuhan, China
| | - Juan Zheng
- Division of Endocrinology and Metabolism, the Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's HospitalToronto, ON, Canada; Department of Physiology, Faculty of Medicine, University of TorontoToronto, ON, Canada
| | - Susanne Wang
- Division of Endocrinology and Metabolism, the Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's HospitalToronto, ON, Canada; Department of Physiology, Faculty of Medicine, University of TorontoToronto, ON, Canada
| | - Harry K Lau
- Division of Endocrinology and Metabolism, the Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's HospitalToronto, ON, Canada; Department of Physiology, Faculty of Medicine, University of TorontoToronto, ON, Canada
| | - Ali Fathi
- Division of Endocrinology and Metabolism, the Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's Hospital Toronto, ON, Canada
| | - Qinghua Wang
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical College, Fudan UniversityShanghai, China; Division of Endocrinology and Metabolism, the Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's HospitalToronto, ON, Canada; Department of Physiology, Faculty of Medicine, University of TorontoToronto, ON, Canada
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23
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Jin T, Weng J. Hepatic functions of GLP-1 and its based drugs: current disputes and perspectives. Am J Physiol Endocrinol Metab 2016; 311:E620-7. [PMID: 27507553 DOI: 10.1152/ajpendo.00069.2016] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 08/08/2016] [Indexed: 12/17/2022]
Abstract
GLP-1 and its based drugs possess extrapancreatic metabolic functions, including that in the liver. These direct hepatic metabolic functions explain their therapeutic efficiency for subjects with insulin resistance. The direct hepatic functions could be mediated by previously assumed "degradation" products of GLP-1 without involving canonic GLP-1R. Although GLP-1 analogs were created as therapeutic incretins, extrapancreatic functions of these drugs, as well as native GLP-1, have been broadly recognized. Among them, the hepatic functions are particularly important. Postprandial GLP-1 release contributes to insulin secretion, which represses hepatic glucose production. This indirect effect of GLP-1 is known as the gut-pancreas-liver axis. Great efforts have been made to determine whether GLP-1 and its analogs possess direct metabolic effects on the liver, as the determination of the existence of direct hepatic effects may advance the therapeutic theory and clinical practice on subjects with insulin resistance. Furthermore, recent investigations on the metabolic beneficial effects of previously assumed "degradation" products of GLP-1 in the liver and elsewhere, including GLP-128-36 and GLP-132-36, have drawn intensive attention. Such investigations may further improve the development and the usage of GLP-1-based drugs. Here, we have reviewed the current advancement and the existing controversies on the exploration of direct hepatic functions of GLP-1 and presented our perspectives that the direct hepatic metabolic effects of GLP-1 could be a GLP-1 receptor-independent event involving Wnt signaling pathway activation.
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Affiliation(s)
- Tianru Jin
- Division of Advanced Diagnostics, Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada; Banting and Best Diabetes Centre, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; and
| | - Jianping Weng
- Department of Endocrinology and Metabolism, Third Affiliated Hospital of Sun Yat-Sen University and Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
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24
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Osborne RI, Ming W, Troutt JS, Siegel RW, Konrad RJ. A dual-monoclonal, sandwich immunoassay specific for glucagon like peptide-19–36/7 (GLP-19–36/7). Clin Biochem 2016; 49:897-902. [DOI: 10.1016/j.clinbiochem.2016.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/17/2016] [Accepted: 03/18/2016] [Indexed: 11/28/2022]
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25
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Schernthaner-Reiter MH, Schernthaner G. Combination therapy of SGLT2 inhibitors with incretin-based therapies for the treatment of type 2 diabetes mellitus: Effects and mechanisms of action. Expert Rev Endocrinol Metab 2016; 11:281-296. [PMID: 30058933 DOI: 10.1586/17446651.2016.1151783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is a growing health problem worldwide; its pathogenesis is multifactorial and its progressive nature often necessitates a combination therapy with multiple antihyperglycemic agents. Sodium glucose cotransporter 2 (SGLT2) inhibitors and the incretin-based therapies - dipeptidyl peptidase 4(DPP-4) inhibitors and glucagon-like peptide 1 (GLP-1) receptor agonists - were introduced for the treatment of T2DM within the last decade. Evidence of the beneficial effects of these antihyperglycemic agents on micro- and macrovascular complications have started to emerge, which will become important in individualizing different combinations of antihyperglycemic agents to different patient populations. We review here the mechanisms of action, glycemic and cardiovascular effects of SGLT2 inhibitors and incretin-based therapies and their combination in the treatment of T2DM.
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Affiliation(s)
- Marie Helene Schernthaner-Reiter
- a Clinical Division of Endocrinology and Metabolism, Department of Internal Medicine III , Medical University of Vienna , Vienna , Austria
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26
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Abstract
PURPOSE/AIM Negative feedback controls in endocrine regulatory systems are well recognized. The incretins and their role in glucose regulation have been of major interest recently. Whether the same negative control system applies to the regulation of incretin secretion is not clear. We sought to examine the hypothesis that exogenous administration of glucagon like peptide-1, GLP-1(7-36) amide or its metabolite GLP-1(9-36) amide, reduces the endogenous basal release of this incretin. MATERIALS AND METHODS We evaluated the endogenous basal release of GLP-1 using two separate study designs. In protocol A we examined the GLP-1(7-36) amide levels during the infusion of GLP-1(9-36) amide. In protocol B, we used PYY and GLP-2 as biomarkers for the endogenous basal release of GLP-1(7-36) amide and assessed the endogenous basal release of these two hormones during the GLP-1(7-36) infusion. Twelve lean and 12 obese subjects were enrolled in protocol A and 10 obese volunteers in protocol B. RESULTS The plasma levels of GLP-1(7-36) amide in protocol A and PYY and GLP-2 in protocol B remained unchanged during the exogenous infusion of GLP-1(9-36) and GLP-1(7-36) amide, respectively. CONCLUSIONS The negative feedback control system as described by inhibition of the release of endogenous hormone while infusing it exogenously was not observed for the basal secretion of GLP-1(7-36) amide.
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Affiliation(s)
| | | | - Olga D. Carlson
- Diabetes Section, National Institute on Aging, Baltimore, MD
| | - Graydon S. Meneilly
- Department of Medicine, University of British Columbia School of Medicine, Vancouver, BC, Canada
| | - Joel F. Habener
- Department of Medicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA
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27
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Sun L, Dai Y, Wang C, Chu Y, Su X, Yang J, Zhou J, Huang W, Qian H. Novel Pentapeptide GLP-1 (32-36) Amide Inhibitsβ-Cell ApoptosisIn Vitroand Improves Glucose Disposal in Streptozotocin-Induced Diabetic Mice. Chem Biol Drug Des 2015; 86:1482-90. [DOI: 10.1111/cbdd.12615] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 06/16/2015] [Accepted: 06/29/2015] [Indexed: 01/12/2023]
Affiliation(s)
- Lidan Sun
- Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases and State Key Laboratory of Natural Medicines; Center of Drug Discovery; China Pharmaceutical University; 24 Tongjiaxiang Nanjing 210009 China
| | - Yuxuan Dai
- Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases and State Key Laboratory of Natural Medicines; Center of Drug Discovery; China Pharmaceutical University; 24 Tongjiaxiang Nanjing 210009 China
| | - Chuandong Wang
- Key Laboratory of Stem Cell Biology; Institute of Health Sciences; Shanghai Jiao Tong University School of Medicine and Shanghai Institutes for Biological Sciences; Chinese Academy of Sciences; Shanghai China
| | - Yingying Chu
- Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases and State Key Laboratory of Natural Medicines; Center of Drug Discovery; China Pharmaceutical University; 24 Tongjiaxiang Nanjing 210009 China
| | - Xin Su
- Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases and State Key Laboratory of Natural Medicines; Center of Drug Discovery; China Pharmaceutical University; 24 Tongjiaxiang Nanjing 210009 China
| | - Jianyong Yang
- Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases and State Key Laboratory of Natural Medicines; Center of Drug Discovery; China Pharmaceutical University; 24 Tongjiaxiang Nanjing 210009 China
| | - Jie Zhou
- Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases and State Key Laboratory of Natural Medicines; Center of Drug Discovery; China Pharmaceutical University; 24 Tongjiaxiang Nanjing 210009 China
| | - Wenlong Huang
- Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases and State Key Laboratory of Natural Medicines; Center of Drug Discovery; China Pharmaceutical University; 24 Tongjiaxiang Nanjing 210009 China
| | - Hai Qian
- Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases and State Key Laboratory of Natural Medicines; Center of Drug Discovery; China Pharmaceutical University; 24 Tongjiaxiang Nanjing 210009 China
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28
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Tomas E, Stanojevic V, McManus K, Khatri A, Everill P, Bachovchin WW, Habener JF. GLP-1(32-36)amide Pentapeptide Increases Basal Energy Expenditure and Inhibits Weight Gain in Obese Mice. Diabetes 2015; 64:2409-19. [PMID: 25858562 PMCID: PMC4477344 DOI: 10.2337/db14-1708] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 02/22/2015] [Indexed: 12/31/2022]
Abstract
The prevalence of obesity-related diabetes is increasing worldwide. Here we report the identification of a pentapeptide, GLP-1(32-36)amide (LVKGRamide), derived from the glucoincretin hormone GLP-1, that increases basal energy expenditure and curtails the development of obesity, insulin resistance, diabetes, and hepatic steatosis in diet-induced obese mice. The pentapeptide inhibited weight gain, reduced fat mass without change in energy intake, and increased basal energy expenditure independent of physical activity. Analyses of tissues from peptide-treated mice reveal increased expression of UCP-1 and UCP-3 in brown adipose tissue and increased UCP-3 and inhibition of acetyl-CoA carboxylase in skeletal muscle, findings consistent with increased fatty acid oxidation and thermogenesis. In palmitate-treated C2C12 skeletal myotubes, GLP-1(32-36)amide activated AMPK and inhibited acetyl-CoA carboxylase, suggesting activation of fat metabolism in response to energy depletion. By mass spectroscopy, the pentapeptide is rapidly formed from GLP-1(9-36)amide, the major form of GLP-1 in the circulation of mice. These findings suggest that the reported insulin-like actions of GLP-1 receptor agonists that occur independently of the GLP-1 receptor might be mediated by the pentapeptide, and the previously reported nonapeptide (FIAWLVKGRamide). We propose that by increasing basal energy expenditure, GLP-1(32-36)amide might be a useful treatment for human obesity and associated metabolic disorders.
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Affiliation(s)
- Eva Tomas
- Laboratory of Molecular Endocrinology and Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Violeta Stanojevic
- Laboratory of Molecular Endocrinology and Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Karen McManus
- Laboratory of Molecular Endocrinology and Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Ashok Khatri
- Laboratory of Molecular Endocrinology and Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Paul Everill
- Department of Biochemistry, Tufts University, Boston, MA
| | | | - Joel F Habener
- Laboratory of Molecular Endocrinology and Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA
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29
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Abstract
Dipeptidyl peptidase-4 (DPP4) is a widely expressed enzyme transducing actions through an anchored transmembrane molecule and a soluble circulating protein. Both membrane-associated and soluble DPP4 exert catalytic activity, cleaving proteins containing a position 2 alanine or proline. DPP4-mediated enzymatic cleavage alternatively inactivates peptides or generates new bioactive moieties that may exert competing or novel activities. The widespread use of selective DPP4 inhibitors for the treatment of type 2 diabetes has heightened interest in the molecular mechanisms through which DPP4 inhibitors exert their pleiotropic actions. Here we review the biology of DPP4 with a focus on: 1) identification of pharmacological vs physiological DPP4 substrates; and 2) elucidation of mechanisms of actions of DPP4 in studies employing genetic elimination or chemical reduction of DPP4 activity. We review data identifying the roles of key DPP4 substrates in transducing the glucoregulatory, anti-inflammatory, and cardiometabolic actions of DPP4 inhibitors in both preclinical and clinical studies. Finally, we highlight experimental pitfalls and technical challenges encountered in studies designed to understand the mechanisms of action and downstream targets activated by inhibition of DPP4.
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Affiliation(s)
- Erin E Mulvihill
- Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
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30
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Manandhar B, Ahn JM. Glucagon-like peptide-1 (GLP-1) analogs: recent advances, new possibilities, and therapeutic implications. J Med Chem 2014; 58:1020-37. [PMID: 25349901 PMCID: PMC4329993 DOI: 10.1021/jm500810s] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
Glucagon-like peptide-1 (GLP-1) is
an incretin that plays important
physiological roles in glucose homeostasis. Produced from intestine
upon food intake, it stimulates insulin secretion and keeps pancreatic
β-cells healthy and proliferating. Because of these beneficial
effects, it has attracted a great deal of attention in the past decade,
and an entirely new line of diabetic therapeutics has emerged based
on the peptide. In addition to the therapeutic applications, GLP-1
analogs have demonstrated a potential in molecular imaging of pancreatic β-cells;
this may be useful in early detection of the disease and evaluation
of therapeutic interventions, including islet transplantation. In
this Perspective, we focus on GLP-1 analogs for their studies on improvement
of biological activities, enhancement of metabolic stability, investigation
of receptor interaction, and visualization of the pancreatic islets.
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Affiliation(s)
- Bikash Manandhar
- Department of Chemistry, University of Texas at Dallas , Richardson, Texas 75080, United States
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31
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Pabreja K, Mohd MA, Koole C, Wootten D, Furness SGB. Molecular mechanisms underlying physiological and receptor pleiotropic effects mediated by GLP-1R activation. Br J Pharmacol 2014; 171:1114-28. [PMID: 23889512 DOI: 10.1111/bph.12313] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 07/10/2013] [Accepted: 07/19/2013] [Indexed: 12/22/2022] Open
Abstract
The incidence of type 2 diabetes in developed countries is increasing yearly with a significant negative impact on patient quality of life and an enormous burden on the healthcare system. Current biguanide and thiazolidinedione treatments for type 2 diabetes have a number of clinical limitations, the most serious long-term limitation being the eventual need for insulin replacement therapy (Table 1). Since 2007, drugs targeting the glucagon-like peptide-1 (GLP-1) receptor have been marketed for the treatment of type 2 diabetes. These drugs have enjoyed a great deal of success even though our underlying understanding of the mechanisms for their pleiotropic effects remain poorly characterized even while major pharmaceutical companies actively pursue small molecule alternatives. Coupling of the GLP-1 receptor to more than one signalling pathway (pleiotropic signalling) can result in ligand-dependent signalling bias and for a peptide receptor such as the GLP-1 receptor this can be exaggerated with the use of small molecule agonists. Better consideration of receptor signalling pleiotropy will be necessary for future drug development. This is particularly important given the recent failure of taspoglutide, the report of increased risk of pancreatitis associated with GLP-1 mimetics and the observed clinical differences between liraglutide, exenatide and the newly developed long-acting exenatide long acting release, albiglutide and dulaglutide.
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Affiliation(s)
- K Pabreja
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Vic., Australia
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32
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Yamazaki S, Satoh H, Watanabe T. Liraglutide enhances insulin sensitivity by activating AMP-activated protein kinase in male Wistar rats. Endocrinology 2014; 155:3288-301. [PMID: 24949659 DOI: 10.1210/en.2013-2157] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We investigated the effects of liraglutide on insulin sensitivity and glucose metabolism in male Wistar rats. The rats were fed a normal chow diet (NCD) or a 60% high-fat diet (HFD) for a total of 4 weeks. After 3 weeks of feeding, they were injected with liraglutide once a day for 7 days. Subsequently, euglycemic-hyperinsulinemic clamp studies were performed after fasting the animals for 8 hours. During the clamp studies on the NCD-fed rats, the glucose infusion rate required for euglycemia was significantly higher in the liraglutide group than in the control group. The clamp hepatic glucose output was significantly lower in the liraglutide group than in the control group, but the insulin-stimulated glucose disposal rate did not change significantly in the liraglutide groups. The clamp studies on the HFD-fed rats revealed that the glucose infusion rate required to achieve euglycemia was significantly higher in the liraglutide group than in the control HFD group, and the insulin-stimulated glucose disposal rate increased significantly in the liraglutide groups. The clamp hepatic glucose output decreased significantly in the liraglutide groups. Consistent with the clamp data, the insulin-stimulated phosphorylation of Akt and AMP-activated protein kinase was enhanced in the livers of the NCD- and HFD-fed rats and in the skeletal muscles of the HFD-fed rats. Oil red O staining indicated that liraglutide also improved hepatic steatosis. In summary, our studies suggest that in normal glucose tolerance states, liraglutide enhances insulin sensitivity in the liver but not in skeletal muscles. However, in insulin-resistant states, liraglutide improves insulin resistance in the liver and muscles and improves fatty liver.
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Affiliation(s)
- Satoru Yamazaki
- Department of Nephrology, Hypertension, Diabetology, Endocrinology, and Metabolism, Fukushima Medical University, Fukushima 960-1295, Japan
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33
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Elahi D, Angeli FS, Vakilipour A, Carlson OD, Tomas E, Egan JM, Habener JF, Shannon RP. GLP-1(32-36)amide, a novel pentapeptide cleavage product of GLP-1, modulates whole body glucose metabolism in dogs. Peptides 2014; 59:20-4. [PMID: 24937653 PMCID: PMC5155305 DOI: 10.1016/j.peptides.2014.06.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 06/06/2014] [Accepted: 06/06/2014] [Indexed: 12/26/2022]
Abstract
We have previously demonstrated in human subjects who under euglycemic clamp conditions GLP-1(9-36)amide infusions inhibit endogenous glucose production without substantial insulinotropic effects. An earlier report indicates that GLP-1(9-36)amide is cleaved to a nonapeptide, GLP-1(28-36)amide and a pentapeptide GLP-1(32-36)amide (LVKGR amide). Here we study the effects of the pentapeptide on whole body glucose disposal during hyperglycemic clamp studies. Five dogs underwent indwelling catheterizations. Following recovery, the dogs underwent a 180 min hyperglycemic clamp (basal glucose +98 mg/dl) in a cross-over design. Saline or pentapeptide (30 pmol kg(-1) min(-1)) was infused during the last 120 min after commencement of the hyperglycemic clamp in a primed continuous manner. During the last 30 min of the pentapeptide infusion, glucose utilization (M) significantly increased to 21.4±2.9 mg kg(-1) min(-1)compared to M of 14.3±1.1 mg kg(-1)min(-1) during the saline infusion (P=0.026, paired t-test; P=0.062, Mann-Whitney U test). During this interval, no significant differences in insulin (26.6±3.2 vs. 23.7±2.5 μU/ml, P=NS) or glucagon secretion (34.0±2.1 vs. 31.7±1.8 pg/ml, P=NS) were observed. These findings demonstrate that under hyperglycemic clamp studies the pentapeptide modulates glucose metabolism by a stimulation of whole-body glucose disposal. Further, the findings suggest that the metabolic benefits previously observed during GLP-1(9-36)amide infusions in humans might be due, at least in part, to the metabolic effects of the pentapeptide that is cleaved from the pro-peptide, GLP-1(9-36)amide in the circulation.
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Affiliation(s)
- Dariush Elahi
- Cardiovascular Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
| | - Franca S Angeli
- Cardiovascular Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Amin Vakilipour
- Cardiovascular Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Olga D Carlson
- Diabetes Section, Clinical Laboratory of Investigation, National Institute on Aging, National Institute of Health, Baltimore, MD, United States
| | - Eva Tomas
- Laboratory of Molecular Endocrinology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Josephine M Egan
- Diabetes Section, Clinical Laboratory of Investigation, National Institute on Aging, National Institute of Health, Baltimore, MD, United States
| | - Joel F Habener
- Laboratory of Molecular Endocrinology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Richard P Shannon
- Cardiovascular Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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Mechanisms of type 2 diabetes resolution after Roux-en-Y gastric bypass. Surg Obes Relat Dis 2014; 10:1028-39. [PMID: 25443077 PMCID: PMC10131082 DOI: 10.1016/j.soard.2014.07.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 07/01/2014] [Accepted: 07/14/2014] [Indexed: 12/17/2022]
Abstract
BACKGROUND Bariatric surgery is the most effective treatment for the reduction of weight and resolution of type 2 diabetes mellitus (T2 DM). The objective of this study was to longitudinally assess hormonal and tissue responses after RYGB. METHODS Eight patients (5 with T2 DM) were studied before and after RYGB. A standardized test meal (STM) was administered before and at 1, 3, 6, 9, 12, and 15 months. Separately, a 2-hour hyperinsulinemic-euglycemic clamp (E-clamp) and a 2-hour hyperglycemic clamp (H-clamp) were performed before and at 1, 3, 6, and 12 months. Glucagon-like peptide-1 (GLP-1) was infused during the last hour of the H-clamp. Body composition was assessed with DXA methodology. RESULTS Enrollment body mass index was 49±3 kg/m(2) (X±SE). STM glucose and insulin responses were normalized by 3 and 6 months. GLP-1 level increased dramatically at 1, 3, and 6 months, normalizing by 12 and 15 months. Insulin sensitivity (M of E-clamp) increased progressively at 3-12 months as fat mass decreased. The insulin response to glucose alone fell progressively over 12 months but the glucose clearance/metabolism (M of H-clamp) did not change significantly until 12 months. In response to GLP-1 infusion, insulin levels fell progressively throughout the 12 months. CONCLUSION The early hypersecretion of GLP-1 leads to hyperinsulinemia and early normalization of glucose levels. The GLP-1 response normalizes within 1 year after surgery. Enhanced peripheral tissue sensitivity to insulin starts at 3 months and is associated with fat mass loss. β-cell sensitivity improves at 12 months and after the loss of ≈33% of excess weight. There is a tightly controlled feedback loop between peripheral tissue sensitivity and β-cell and L-cell (GLP-1) responses.
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Taing MW, Rose FJ, Whitehead JP. GLP-1(28-36)amide, the Glucagon-like peptide-1 metabolite: friend, foe, or pharmacological folly? DRUG DESIGN DEVELOPMENT AND THERAPY 2014; 8:677-88. [PMID: 24940046 PMCID: PMC4051623 DOI: 10.2147/dddt.s35723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The glucagon-like peptide-1 (GLP-1) axis has emerged as a major therapeutic target for the treatment of type 2 diabetes. GLP-1 mediates its key insulinotropic effects via a G-protein coupled receptor expressed on β-cells and other pancreatic cell types. The insulinotropic activity of GLP-1 is terminated via enzymatic cleavage by dipeptidyl peptidase-4. Until recently, GLP-1-derived metabolites were generally considered metabolically inactive; however, accumulating evidence indicates some have biological activity that may contribute to the pleiotropic effects of GLP-1 independent of the GLP-1 receptor. Recent reports describing the putative effects of one such metabolite, the GLP-1-derived nonapeptide GLP-1(28-36) amide, are the focus of this review. Administration of the nonapeptide elevates cyclic adenosine monophosphate (cAMP) and activates protein kinase A, β-catenin, and cAMP response-element binding protein in pancreatic β-cells and hepatocytes. In stressed cells, the nonapeptide targets the mitochondria and, via poorly defined mechanisms, helps to maintain mitochondrial membrane potential and cellular adenosine triphosphate levels and to reduce cytotoxicity and apoptosis. In mouse models of diet-induced obesity, treatment with the nonapeptide reduces weight gain and ameliorates associated pathophysiology, including hyperglycemia, hyperinsulinemia, and hepatic steatosis. Nonapeptide administration in a streptozotocin-induced model of type 1 diabetes also improves glucose disposal concomitant with elevated insulin levels and increased β-cell mass and proliferation. Collectively, these results suggest some of the beneficial effects of GLP-1 receptor analogs may be mediated by the nonapeptide. However, the concentrations required to elicit some of these effects are in the micromolar range, leading to reservations about potentially related therapeutic benefits. Moreover, although controversial, concerns have been raised about the potential for incretin-based therapies to promote pancreatitis and pancreatic and thyroid cancers. The effects ascribed to the nonapeptide make it a potential contributor to such outcomes, raising additional questions about its therapeutic suitability. Notwithstanding, the nonapeptide, like other GLP-1 metabolites, appears to be biologically active. Increasing understanding of such noncanonical GLP-1 activities should help to improve future incretin-based therapeutics.
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Affiliation(s)
- Meng-Wong Taing
- Metabolic Medicine, Mater Research Institute, University of Queensland, Australia ; School of Pharmacy, University of Queensland, Brisbane, QLD, Australia
| | - Felicity J Rose
- Metabolic Medicine, Mater Research Institute, University of Queensland, Australia ; University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, QLD, Australia
| | - Jonathan P Whitehead
- Metabolic Medicine, Mater Research Institute, University of Queensland, Australia
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The glucoregulatory benefits of glucagon-like peptide-1 (7-36) amide infusion during intensive insulin therapy in critically ill surgical patients: a pilot study. Crit Care Med 2014; 42:638-45. [PMID: 24247476 DOI: 10.1097/ccm.0000000000000035] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
OBJECTIVES Intensive insulin therapy for tight glycemic control in critically ill surgical patients has been shown to reduce mortality; however, intensive insulin therapy is associated with iatrogenic hypoglycemia and increased variability of blood glucose levels. The incretin glucagon-like peptide-1 (7-36) amide is both insulinotropic and insulinomimetic and has been suggested as an adjunct to improve glycemic control in critically ill patients. We hypothesized that the addition of continuous infusion of glucagon-like peptide-1 to intensive insulin therapy would result in better glucose control, reduced requirement of exogenous insulin administration, and fewer hypoglycemic events. DESIGN Prospective, randomized, double-blind, placebo-controlled clinical trial. SETTING Surgical or burn ICU. PATIENTS Eighteen patients who required intensive insulin therapy. INTERVENTIONS A 72-hour continuous infusion of either glucagon-like peptide-1 (1.5 pmol/kg/min) or normal saline plus intensive insulin therapy. MEASUREMENTS AND MAIN RESULTS The glucagon-like peptide-1 cohort (n = 9) and saline cohort (n = 9) were similar in age, Acute Physiology and Chronic Health Evaluation score, and history of diabetes. Blood glucose levels in the glucagon-like peptide-1 group were better controlled with much less variability. The coefficient of variation of blood glucose ranged from 7.2% to 30.4% in the glucagon-like peptide-1 group and from 19.8% to 56.8% in saline group. The mean blood glucose coefficient of variation for the glucagon-like peptide-1 and saline groups was 18.0% ± 2.7% and 30.3% ± 4.0% (p = 0.010), respectively. The 72-hour average insulin infusion rates were 3.37 ± 0.61 and 4.57 ± 1.18 U/hr (p = not significant). The incidents of hypoglycemia (≤ 2.78 mmol/L) in both groups were low (one in the glucagon-like peptide-1 group, three in the saline group). CONCLUSIONS Glucagon-like peptide-1 (7-36) amide is a safe and efficacious form of adjunct therapy in patients with hyperglycemia in the surgical ICU setting. Improved stability of blood glucose is a favorable outcome, which enhances the safety of intensive insulin therapy. Larger studies of this potentially valuable therapy for glycemic control in the ICU are justified.
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Abstract
Glucagon-like (GLP-1) is a peptide hormone secreted from the small intestine in response to nutrient ingestion. GLP-1 stimulates insulin secretion in a glucose-dependent manner, inhibits glucagon secretion and gastric emptying, and reduces appetite. Because of the short circulating half-life of the native GLP-1, novel GLP-1 receptor (GLP-1R) agonists and analogs and dipeptidyl peptidase 4 (DPP-4) inhibitors have been developed to facilitate clinical use. Emerging evidence indicates that GLP-1-based therapies are safe and may provide cardiovascular (CV) benefits beyond glycemic control. Preclinical and clinical studies are providing increasing evidence that GLP-1 therapies may positively affect CV function and metabolism by salutary effects on CV risk factors as well as via direct cardioprotective actions. However, the mechanisms whereby the various classes of incretin-based therapies exert CV effects may be mechanistically distinct and may not necessarily lead to similar CV outcomes. In this review, we will discuss the potential mechanisms and current understanding of CV benefits of native GLP-1, GLP-1R agonists and analogs, and of DPP-4 inhibitor therapies as a means to compare their putative CV benefits.
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Affiliation(s)
- Franca S Angeli
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Hospital of the University of Pennsylvania, 3400 Spruce Street, Centrex 100, Philadelphia, Pennsylvania 19104, USA
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Kuc RE, Maguire JJ, Siew K, Patel S, Derksen DR, Margaret Jackson V, O'Shaughnessey KM, Davenport AP. Characterization of [¹²⁵I]GLP-1(9-36), a novel radiolabeled analog of the major metabolite of glucagon-like peptide 1 to a receptor distinct from GLP1-R and function of the peptide in murine aorta. Life Sci 2014; 102:134-8. [PMID: 24641952 DOI: 10.1016/j.lfs.2014.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 01/29/2014] [Accepted: 03/04/2014] [Indexed: 12/26/2022]
Abstract
AIMS Glucagon-like peptide 1 (GLP-1) is an insulin secretagogue, released in response to meal ingestion and efficiently lowers blood glucose in Type 2 diabetic patients. GLP-1(7-36) is rapidly metabolized by dipeptidyl peptidase IV to the major metabolite GLP-1(9-36)-amide, often thought to be inactive. Inhibitors of this enzyme are widely used to treat diabetes. Our aim was to characterize the binding of GLP-1(9-36) to native mouse tissues and to cells expressing GLP1-R as well as to measure functional responses in the mouse aorta compared with GLP-1(7-36). MAIN METHODS The affinity of [(125)I]GLP-1(7-36) and [(125)I]GLP-1(9-36) was measured in mouse tissues by saturation binding and autoradiography used to determine receptor distribution. The affinity of both peptides was compared in binding to recombinant GLP-1 receptors using cAMP and scintillation proximity assays. Vasoactivity was determined in mouse aortae in vitro. KEY FINDINGS In cells expressing GLP-1 receptors, GLP-1(7-36) bound with the expected high affinities (0.1 nM) and an EC50 of 0.07 nM in cAMP assays but GLP-1(9-36) bound with 70,000 and 100,000 fold lower affinities respectively. In contrast, in mouse brain, both labeled peptides bound with a single high affinity, with Hill slopes close to unity, although receptor density was an order of magnitude lower for [(125)I]GLP-1(9-36). In functional experiments both peptides had similar potencies, GLP-1(7-36), pD2=7.40 ± 0.24 and GLP-1(9-36), pD2=7.57 ± 0.64. SIGNIFICANCE These results suggest that GLP-1(9-36) binds and has functional activity in the vasculature but these actions may be via a pathway that is distinct from the classical GLP-1 receptor and insulin secretagogue actions.
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Affiliation(s)
- Rhoda E Kuc
- Clinical Pharmacology Unit, Box 110, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Janet J Maguire
- Clinical Pharmacology Unit, Box 110, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Keith Siew
- Clinical Pharmacology Unit, Box 110, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Sheena Patel
- Pfizer, Cardiovascular Medicine, Cambridge, MA, USA
| | | | | | | | - Anthony P Davenport
- Clinical Pharmacology Unit, Box 110, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK.
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Eng H, Sharma R, McDonald TS, Landis MS, Stevens BD, Kalgutkar AS. Pharmacokinetics and metabolism studies on the glucagon-like peptide-1 (GLP-1)-derived metabolite GLP-1(9-36)amide in male Beagle dogs. Xenobiotica 2014; 44:842-8. [PMID: 24588343 DOI: 10.3109/00498254.2014.897011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Glucagon-like peptide-1 (GLP-1)(7-36)amide is a 30-amino acid peptide hormone that is secreted from intestinal enteroendocrine L-cells in response to nutrients. GLP-1(7-36)amide possesses potent insulinotropic actions in the augmentation of glucose-dependent insulin secretion. GLP-1(7-36)amide is rapidly metabolized by dipeptidyl peptidase-IV to yield GLP-1(9-36)amide as the principal metabolite. Contrary to the earlier notion that peptide cleavage products of native GLP-1(7-36)amide [including GLP-1(9-36)amide] are pharmacologically inactive, recent studies have demonstrated cardioprotective and insulinomimetic effects with GLP-1(9-36)amide in mice, dogs and humans. In the present work, in vitro metabolism and pharmacokinetic properties of GLP-1(9-36)amide have been characterized in dogs, since this preclinical species has been used as an animal model to demonstrate the in vivo vasodilatory and cardioprotective effects of GLP-1(9-36)amide. A liquid chromatography tandem mass spectrometry assay was developed for the quantitation of the intact peptide in hepatocyte incubations as opposed to a previously reported enzyme-linked immunosorbent assay. Although GLP-1(9-36)amide was resistant to proteolytic cleavage in dog plasma and bovine serum albumin (t1/2>240 min), the peptide was rapidly metabolized in dog hepatocytes with a t1/2 of 110 min. Metabolite identification studies in dog hepatocytes revealed a variety of N-terminus cleavage products, most of which, have also been observed in human and mouse hepatocytes. Proteolysis at the C-terminus was not observed in GLP-1(9-36)amide. Following the administration of a single intravenous bolus dose (20 µg/kg) to male Beagle dogs, GLP-1(9-36)amide exhibited a mean plasma clearance of 15 ml/min/kg and a low steady state distribution volume of 0.05 l/kg, which translated into a short elimination half life of 0.05 h. Following subcutaneous administration of GLP-1(9-36)amide at 50 µg/kg, systemic exposure of GLP-1(9-36)amide as ascertained from maximal plasma concentrations and area under the plasma concentration-time curve from zero to infinity was 44 ng/ml and 32 ng h/ml, respectively. The subcutaneous bioavailability of GLP-1(9-36)amide in dogs was 57%. Our findings raise the possibility that the cardioprotective effects of GLP-1(9-36)amide in the conscious dog model of pacing-induced heart failure might be due, at least in part, to the actions of additional downstream metabolites, which are obtained from proteolytic cleavage of the peptide backbone in the parent compound in the liver.
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Affiliation(s)
- Heather Eng
- Pfizer Inc. , Eastern Point Road, Groton, CT , USA and
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Nadkarni P, Chepurny OG, Holz GG. Regulation of glucose homeostasis by GLP-1. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014. [PMID: 24373234 DOI: 10.1016/b978-0-12-800101-1.00002-8.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/01/2022]
Abstract
Glucagon-like peptide-1(7-36)amide (GLP-1) is a secreted peptide that acts as a key determinant of blood glucose homeostasis by virtue of its abilities to slow gastric emptying, to enhance pancreatic insulin secretion, and to suppress pancreatic glucagon secretion. GLP-1 is secreted from L cells of the gastrointestinal mucosa in response to a meal, and the blood glucose-lowering action of GLP-1 is terminated due to its enzymatic degradation by dipeptidyl-peptidase-IV (DPP-IV). Released GLP-1 activates enteric and autonomic reflexes while also circulating as an incretin hormone to control endocrine pancreas function. The GLP-1 receptor (GLP-1R) is a G protein-coupled receptor that is activated directly or indirectly by blood glucose-lowering agents currently in use for the treatment of type 2 diabetes mellitus (T2DM). These therapeutic agents include GLP-1R agonists (exenatide, liraglutide, lixisenatide, albiglutide, dulaglutide, and langlenatide) and DPP-IV inhibitors (sitagliptin, vildagliptin, saxagliptin, linagliptin, and alogliptin). Investigational agents for use in the treatment of T2DM include GPR119 and GPR40 receptor agonists that stimulate the release of GLP-1 from L cells. Summarized here is the role of GLP-1 to control blood glucose homeostasis, with special emphasis on the advantages and limitations of GLP-1-based therapeutics.
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Affiliation(s)
- Prashant Nadkarni
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA; Joslin Diabetes Center, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - Oleg G Chepurny
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - George G Holz
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA; Department of Pharmacology, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA.
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Nadkarni P, Chepurny OG, Holz GG. Regulation of glucose homeostasis by GLP-1. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 121:23-65. [PMID: 24373234 DOI: 10.1016/b978-0-12-800101-1.00002-8] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Glucagon-like peptide-1(7-36)amide (GLP-1) is a secreted peptide that acts as a key determinant of blood glucose homeostasis by virtue of its abilities to slow gastric emptying, to enhance pancreatic insulin secretion, and to suppress pancreatic glucagon secretion. GLP-1 is secreted from L cells of the gastrointestinal mucosa in response to a meal, and the blood glucose-lowering action of GLP-1 is terminated due to its enzymatic degradation by dipeptidyl-peptidase-IV (DPP-IV). Released GLP-1 activates enteric and autonomic reflexes while also circulating as an incretin hormone to control endocrine pancreas function. The GLP-1 receptor (GLP-1R) is a G protein-coupled receptor that is activated directly or indirectly by blood glucose-lowering agents currently in use for the treatment of type 2 diabetes mellitus (T2DM). These therapeutic agents include GLP-1R agonists (exenatide, liraglutide, lixisenatide, albiglutide, dulaglutide, and langlenatide) and DPP-IV inhibitors (sitagliptin, vildagliptin, saxagliptin, linagliptin, and alogliptin). Investigational agents for use in the treatment of T2DM include GPR119 and GPR40 receptor agonists that stimulate the release of GLP-1 from L cells. Summarized here is the role of GLP-1 to control blood glucose homeostasis, with special emphasis on the advantages and limitations of GLP-1-based therapeutics.
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Affiliation(s)
- Prashant Nadkarni
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA; Joslin Diabetes Center, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - Oleg G Chepurny
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - George G Holz
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA; Department of Pharmacology, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA.
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Sharma R, McDonald TS, Eng H, Limberakis C, Stevens BD, Patel S, Kalgutkar AS. In vitro metabolism of the glucagon-like peptide-1 (GLP-1)-derived metabolites GLP-1(9-36)amide and GLP-1(28-36)amide in mouse and human hepatocytes. Drug Metab Dispos 2013; 41:2148-57. [PMID: 24056839 DOI: 10.1124/dmd.113.054254] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous studies have revealed that the glucoincretin hormone glucagon-like peptide-1 (GLP-1)(7-36)amide is metabolized by dipeptidyl peptidase-IV (DPP-IV) and neutral endopeptidase 24.11 (NEP) to yield GLP-1(9-36)amide and GLP-1(28-36)amide, respectively, as the principal metabolites. Contrary to the previous notion that GLP-1(7-36)amide metabolites are pharmacologically inactive, recent studies have demonstrated cardioprotective and insulinomimetic effects with both GLP-1(9-36)amide and GLP-1(28-36)amide in animals and humans. In the present work, we examined the metabolic stability of the two GLP-1(7-36)amide metabolites in cryopreserved hepatocytes, which have been used to demonstrate the in vitro insulin-like effects of GLP-1(9-36)amide and GLP-1(28-36)amide on gluconeogenesis. To examine the metabolic stability of the GLP-1(7-36)amide metabolites, a liquid chromatography-tandem mass spectrometry assay was developed for the quantitation of the intact peptides in hepatocyte incubations. GLP-1(9-36)amide and GLP-1(28-36)amide were rapidly metabolized in mouse [GLP-1(9-36)amide: t(1/2) = 52 minutes; GLP-1(28-36)amide: t(1/2) = 13 minutes] and human hepatocytes [GLP-1(9-36)amide: t(1/2) = 180 minutes; GLP-1(28-36)amide: t(1/2) = 24 minutes), yielding a variety of N-terminal cleavage products that were characterized using mass spectrometry. Metabolism at the C terminus was not observed for either peptides. The DPP-IV and NEP inhibitors diprotin A and phosphoramidon, respectively, did not induce resistance in the two peptides toward proteolytic cleavage. Overall, our in vitro findings raise the intriguing possibility that the insulinomimetic effects of GLP-1(9-36)amide and GLP-1(28-36)amide on gluconeogenesis and oxidative stress might be due, at least in part, to the actions of additional downstream metabolites, which are obtained from the enzymatic cleavage of the peptide backbone in the parent compounds.
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Affiliation(s)
- Raman Sharma
- Pharmacokinetics, Dynamics and Metabolism-New Chemical Entities (R.S., T.S.M., H.E.) and Cardiovascular, Metabolic and Endocrine Diseases Medicinal Chemistry (C.L.), Pfizer, Inc., Groton, Connecticut; and Pharmacokinetics, Dynamics and Metabolism-New Chemical Entities (A.S.K.), Cardiovascular, Metabolic and Endocrine Diseases Medicinal Chemistry (B.D.S.), and Cardiovascular, Metabolic and Endocrine Diseases Research Unit (S.P.), Pfizer, Inc, Cambridge, Massachusetts
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Sathananthan M, Farrugia LP, Miles JM, Piccinini F, Dalla Man C, Zinsmeister AR, Cobelli C, Rizza RA, Vella A. Direct effects of exendin-(9,39) and GLP-1-(9,36)amide on insulin action, β-cell function, and glucose metabolism in nondiabetic subjects. Diabetes 2013; 62:2752-6. [PMID: 23545708 PMCID: PMC3717878 DOI: 10.2337/db13-0140] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Exendin-(9,39) is a competitive antagonist of glucagon-like peptide-1 (GLP-1) at its receptor. However, it is unclear if it has direct and unique effects of its own. We tested the hypothesis that exendin-(9,39) and GLP-1-(9,36)amide have direct effects on hormone secretion and β-cell function as well as glucose metabolism in healthy subjects. Glucose containing [3-(3)H]glucose was infused to mimic the systemic appearance of glucose after a meal. Saline, GLP-1-(9,36)amide, or exendin-(9,39) at 30 pmol/kg/min (Ex 30) or 300 pmol/kg/min (Ex 300) were infused in random order on separate days. Integrated glucose concentrations were slightly but significantly increased by exendin-(9,39) (365 ± 43 vs. 383 ± 35 vs. 492 ± 49 vs. 337 ± 50 mmol per 6 h, saline, Ex 30, Ex 300, and GLP-1-[9,36]amide, respectively; P = 0.05). Insulin secretion did not differ among groups. However, insulin action was lowered by exendin-(9,39) (25 ± 4 vs. 20 ± 4 vs. 18 ± 3 vs. 21 ± 4 10(-4) dL/kg[min per μU/mL]; P = 0.02), resulting in a lower disposition index (DI) during exendin-(9,39) infusion (1,118 ± 118 vs. 816 ± 83 vs. 725 ± 127 vs. 955 ± 166 10(-14) dL/kg/min(2) per pmol/L; P = 0.003). Endogenous glucose production and glucose disappearance did not differ significantly among groups. We conclude that exendin-(9,39), but not GLP-1-(9,36)amide, decreases insulin action and DI in healthy humans.
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Affiliation(s)
- Matheni Sathananthan
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Luca P. Farrugia
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - John M. Miles
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | | | - Chiara Dalla Man
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Alan R. Zinsmeister
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota
| | - Claudio Cobelli
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Robert A. Rizza
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Adrian Vella
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
- Corresponding author: Adrian Vella,
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Abstract
SCFA resulting from the microbial fermentation of carbohydrates have been linked to increased glucagon-like peptide-1 (GLP-1) secretion from the gastrointestinal tract in cell and animal models; however, there is little direct evidence in human subjects to confirm this. The present study was designed to investigate whether endogenous plasma GLP-1 concentrations increase following acute consumption of 48 g dietary fibre (as resistant starch (RS) from high-amylose maize type 2 RS (HAM-RS2)) compared with a matched placebo. A total of thirty healthy males participated in the present randomised cross-over study where HAM-RS2 or placebo was consumed as part of standardised breakfast and lunch meals. Changes to GLP-1, glucose, insulin and C-peptide were assessed half hourly for 7 h. Following the breakfast meal, plasma GLP-1 concentrations were lower with HAM-RS2 compared with the placebo (P = 0·025). However, there was no significant difference between the supplements following the lunch meal. Plasma insulin concentrations were significantly lower following the lunch meal (P = 0·034) with HAM-RS2 than with the placebo, but were not different after breakfast. Plasma glucose and C-peptide concentrations did not differ at any point. These results suggest that increased dietary fibre intake, in the form of HAM-RS2, does not acutely increase endogenous GLP-1 concentrations in human subjects. Further fibre feeding studies are required to determine whether GLP-1 concentrations may increase following longer-term consumption.
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Habener JF, Stanojevic V. Alpha cells come of age. Trends Endocrinol Metab 2013; 24:153-63. [PMID: 23260869 DOI: 10.1016/j.tem.2012.10.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 10/27/2012] [Accepted: 10/30/2012] [Indexed: 02/07/2023]
Abstract
The alpha cells that coinhabit the islets with the insulin-producing beta cells have recently captured the attention of diabetes researchers because of new breakthrough findings highlighting the importance of these cells in the maintenance of beta cell health and functions. In normal physiological conditions alpha cells produce glucagon but in conditions of beta cell injury they also produce glucagon-like peptide-1 (GLP-1), a growth and survival factor for beta cells. In this review we consider these new findings on the functions of alpha cells. Alpha cells remain somewhat enigmatic inasmuch as they now appear to be important in the maintenance of the health of beta cells, but their production of glucagon promotes diabetes. This circumstance prompts an examination of approaches to coax alpha cells to produce GLP-1 instead of glucagon.
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Affiliation(s)
- Joel F Habener
- Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Boston, MA 02114, USA.
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Dhanesha N, Joharapurkar A, Shah G, Dhote V, Kshirsagar S, Bahekar R, Jain M. Exendin-4 reduces glycemia by increasing liver glucokinase activity: an insulin independent effect. Pharmacol Rep 2012; 64:140-9. [PMID: 22580530 DOI: 10.1016/s1734-1140(12)70740-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 11/04/2011] [Indexed: 01/13/2023]
Abstract
Exendin-4 is a stable peptide agonist of GLP-1 receptor that exhibits insulinotropic actions. Some in vivo studies indicated insulin-independent glucoregulatory actions of exendin-4. That finding prompted us to evaluate effects of exendin-4 on liver glucose metabolism. Acute and chronic treatment of exendin-4 resulted in increased hepatic glucokinase activity in db/db mice but not in lean C57 mice. The stimulatory effect of exendin-4 on glucokinase activity was abrogated by exendin 9-39, a GLP-1 antagonist. Exposure of hepatocytes isolated from db/db mice to exendin-4 elicited a rapid increase in cAMP, which was synergized by IBMX, an inhibitor of cAMP degradation. The GLP-1 antagonist, exendin 9-39, has abolished the cAMP generating effects of exendin-4 as well. Furthermore, chronic treatment of exendin-4 in streptozotocin-treated C57 mice resulted in restoration of hepatic glycogen, an indicator of improved glucose metabolism, without apparent changes in serum insulin levels. In conclusion, exendin-4 increased glucokinase enzyme protein and activity in liver via a mechanism parallel to and independent of insulin. Exendin-4-induced increase in hepatic glucokinase activity is more pronounced in the presence of hepatic insulin resistance. This beneficial effect of exendin-4 on liver glucokinase activity may be mediated by GLP-1 receptor.
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Affiliation(s)
- Nirav Dhanesha
- Department of Pharmacology and Toxicology, Zydus Research Centre, Cadila Healthcare Ltd., Sarkhej-Bavla N.H. No. 8A, Moraiya, Ahmedabad 382210, India
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Dhanesha N, Joharapurkar A, Shah G, Dhote V, Kshirsagar S, Bahekar R, Jain M. Exendin-4 ameliorates diabetic symptoms through activation of glucokinase. J Diabetes 2012; 4:369-77. [PMID: 22356440 DOI: 10.1111/j.1753-0407.2012.00193.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Glucagon-like peptide-1 (GLP-1) and its stable analogue exendin-4 maintain glucose homeostasis by modulating insulin secretion from pancreatic β-cells and controlling hepatic glucose output. Glucokinase (GK), by catalysing the first step in glycolysis, plays an important role in glucose-stimulated insulin secretion and hepatic glucose metabolism. In the present study, we investigated the effects of exendin-4 on GK in high fat-fed and alloxan-treated diabetic mice. METHODS The effects of alloxan (5, 10 and 20 μmol/L) on insulin release from isolated murine islets, as well as glycogen synthesis by isolated murine hepatocytes, were assessed. The effects of exendin-4 (10 nmol/kg, twice daily for 4 weeks) were assessed in high fat-fed, alloxan (50 mg/kg, i.v.)-treated C57 mice. Glucokinase activity was assessed in the same model. RESULTS Pretreatment with exendin-4 attenuated alloxan-induced decreases in insulin release and glycogen synthesis in islets and hepatocytes. The alloxan-induced decrease in the GK activity in islets and hepatocytes was also ameliorated by exendin-4 treatment. Pretreatment with the GLP-1 receptor antagonist exendin-9 (100 nmol/L) blocked the effects of exendin-4 on the liver and pancreas. Treatment of high-fat fed, alloxan-treated diabetic mice with exendin-4 (10 nmol/L, i.p.) reduced the severity of diabetic symptoms. Specifically, exendin-4 treatment reduced serum glucose by 50% and %HbA1c by 24% compared with control and significantly decreased HOMA-IR by 39% and increased HOMA-β by 150%. In addition, exendin-4 treatment significantly reduced body weight by 6.8% and serum triglycerides by 35%. CONCLUSIONS The results indicate that glucose-stimulated insulin release and glycogen synthesis are decreased by alloxan due to reduced GK activity. These findings provide further insight into the mechanism by which exendin-4 regulates glucose homeostasis.
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Affiliation(s)
- Nirav Dhanesha
- Department of Pharmacology and Toxicology, Zydus Research Centre, Cadila Healthcare Limited, Ahmedabad, India
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Xiong X, Shao W, Jin T. New insight into the mechanisms underlying the function of the incretin hormone glucagon-like peptide-1 in pancreatic β-cells: the involvement of the Wnt signaling pathway effector β-catenin. Islets 2012; 4:359-65. [PMID: 23314611 PMCID: PMC3605164 DOI: 10.4161/isl.23345] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
During the past two decades, the exploration of function of two incretin hormones, namely glucagon-like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP), has led to the development of two categories of novel therapeutic agents for diabetes and its complications, known as GLP-1 receptor (GLP-1R) agonists and DPP-IV inhibitors. Mechanisms underlying the function of GLP-1, however, still need to be further explored. GLP-1 not only functions as an incretin hormone in stimulating insulin secretion in response to nutritional, hormonal and neuronal stimulations, but also acts as an "insulin-like" factor in β-cell and extra-pancreatic organs. In addition to these insulinotropic and insulinomimetic effects, GLP-1 was shown to exert its protective effect in β-cell by repressing the expression of TxNIP, a mediator of glucolipotoxicity. A number of recent studies have shown that the Wnt signaling pathway effector, the bipartite transcription factor β-catenin/TCF, controls not only the production of GLP-1, but also the function of GLP-1. Furthermore, previously assumed "degradation" products of GLP-1(7-36)amide, including GLP-1(9-36)amide and GLP-1(28-36)amide, have been shown to exert beneficial effect in pancreas and extra-pancreatic tissues or cell lineages. Here we summarized our current knowledge on the metabolic, proliferative and protective effects of GLP-1(7-36)amide and its cleavage fragments, mainly focusing on pancreatic β-cells and the involvement of the Wnt signaling pathway effector β-catenin.
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Affiliation(s)
- Xiaoquan Xiong
- Department of Physiology; University of Toronto; Toronto, ON Canada
- Toronto General Research Institute, University Health Network; Toronto, ON Canada
| | - Weijuan Shao
- Department of Physiology; University of Toronto; Toronto, ON Canada
- Toronto General Research Institute, University Health Network; Toronto, ON Canada
| | - Tianru Jin
- Department of Physiology; University of Toronto; Toronto, ON Canada
- Institute of Medical Science; University of Toronto; Toronto, ON Canada
- Toronto General Research Institute, University Health Network; Toronto, ON Canada
- Correspondence to: Tianru Jin;
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Zhao L, Ye H, Li D, Lao X, Li J, Wang Z, Xiao L, Wu Z, Huang J. Glucagon-like peptide-1(1–37) can enhance blood glucose homeostasis in mice. ACTA ACUST UNITED AC 2012; 178:1-5. [DOI: 10.1016/j.regpep.2012.06.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Revised: 05/03/2012] [Accepted: 06/22/2012] [Indexed: 12/25/2022]
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Donnelly D. The structure and function of the glucagon-like peptide-1 receptor and its ligands. Br J Pharmacol 2012; 166:27-41. [PMID: 21950636 DOI: 10.1111/j.1476-5381.2011.01687.x] [Citation(s) in RCA: 171] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Glucagon-like peptide-1(7-36)amide (GLP-1) is a 30-residue peptide hormone released from intestinal L cells following nutrient consumption. It potentiates the glucose-induced secretion of insulin from pancreatic beta cells, increases insulin expression, inhibits beta-cell apoptosis, promotes beta-cell neogenesis, reduces glucagon secretion, delays gastric emptying, promotes satiety and increases peripheral glucose disposal. These multiple effects have generated a great deal of interest in the discovery of long-lasting agonists of the GLP-1 receptor (GLP-1R) in order to treat type 2 diabetes. This review article summarizes the literature regarding the discovery of GLP-1 and its physiological functions. The structure, function and sequence-activity relationships of the hormone and its natural analogue exendin-4 (Ex4) are reviewed in detail. The current knowledge of the structure of GLP-1R, a Family B GPCR, is summarized and discussed, before its known interactions with the principle peptide ligands are described and summarized. Finally, progress in discovering non-peptide ligands of GLP-1R is reviewed. GLP-1 is clearly an important hormone linking nutrient consumption with blood sugar control, and therefore knowledge of its structure, function and mechanism of action is of great importance.
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Affiliation(s)
- Dan Donnelly
- Faculty of Biological Sciences, University of Leeds, Leeds, UK.
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