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Lewis JE, Nuzzaci D, James-Okoro PP, Montaner M, O'Flaherty E, Darwish T, Hayashi M, Liberles SD, Hornigold D, Naylor J, Baker D, Gribble FM, Reimann F. Stimulating intestinal GIP release reduces food intake and body weight in mice. Mol Metab 2024; 84:101945. [PMID: 38653401 PMCID: PMC11070708 DOI: 10.1016/j.molmet.2024.101945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 04/08/2024] [Accepted: 04/16/2024] [Indexed: 04/25/2024] Open
Abstract
OBJECTIVE Glucose dependent insulinotropic polypeptide (GIP) is well established as an incretin hormone, boosting glucose-dependent insulin secretion. However, whilst anorectic actions of its sister-incretin glucagon-like peptide-1 (GLP-1) are well established, a physiological role for GIP in appetite regulation is controversial, despite the superior weight loss seen in preclinical models and humans with GLP-1/GIP dual receptor agonists compared with GLP-1R agonism alone. METHODS We generated a mouse model in which GIP expressing K-cells can be activated through hM3Dq Designer Receptor Activated by Designer Drugs (DREADD, GIP-Dq) to explore physiological actions of intestinally-released GIP. RESULTS In lean mice, Dq-stimulation of GIP expressing cells increased plasma GIP to levels similar to those found postprandially. The increase in GIP was associated with improved glucose tolerance, as expected, but also triggered an unexpected robust inhibition of food intake. Validating that this represented a response to intestinally-released GIP, the suppression of food intake was prevented by injecting mice peripherally or centrally with antagonistic GIPR-antibodies, and was reproduced in an intersectional model utilising Gip-Cre/Villin-Flp to limit Dq transgene expression to K-cells in the intestinal epithelium. The effects of GIP cell activation were maintained in diet induced obese mice, in which chronic K-cell activation reduced food intake and attenuated body weight gain. CONCLUSIONS These studies establish a physiological gut-brain GIP-axis regulating food intake in mice, adding to the multi-faceted metabolic effects of GIP which need to be taken into account when developing GIPR-targeted therapies for obesity and diabetes.
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Affiliation(s)
- Jo E. Lewis
- Institute of Metabolic Science-Metabolic Research Laboratories & MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, UK
| | - Danae Nuzzaci
- Institute of Metabolic Science-Metabolic Research Laboratories & MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, UK
| | - Paula-Peace James-Okoro
- Institute of Metabolic Science-Metabolic Research Laboratories & MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, UK
| | - Mireia Montaner
- Institute of Metabolic Science-Metabolic Research Laboratories & MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, UK
| | - Elisabeth O'Flaherty
- Institute of Metabolic Science-Metabolic Research Laboratories & MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, UK
| | - Tamana Darwish
- Institute of Metabolic Science-Metabolic Research Laboratories & MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, UK
| | - Marito Hayashi
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Stephen D. Liberles
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - David Hornigold
- Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Jacqueline Naylor
- Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - David Baker
- Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Fiona M. Gribble
- Institute of Metabolic Science-Metabolic Research Laboratories & MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, UK
| | - Frank Reimann
- Institute of Metabolic Science-Metabolic Research Laboratories & MRC-Metabolic Diseases Unit, University of Cambridge, Cambridge, UK
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Sicinski KM, Sürmeli D, Du J, Raman VS, Montanari V, Lee M, Harwood BN, Kopin AS, Beinborn M, Kumar K. A Robust Platform for the Molecular Design of Potent, Protease-Stable, Long-Acting GIP Analogues. J Med Chem 2024. [PMID: 38458970 DOI: 10.1021/acs.jmedchem.4c00111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2024]
Abstract
Glucose-dependent insulinotropic peptide (GIP) is a 42-amino acid peptide hormone that regulates postprandial glucose levels. GIP binds to its cognate receptor, GIPR, and mediates metabolic physiology by improved insulin sensitivity, β-cell proliferation, increased energy consumption, and stimulated glucagon secretion. Dipeptidyl peptidase-4 (DPP4) catalyzes the rapid inactivation of GIP within 6 min in vivo. Here, we report a molecular platform for the design of GIP analogues that are refractory to DPP4 action and exhibit differential activation of the receptor, thus offering potentially hundreds of GIP-based compounds to fine-tune pharmacology. The lead compound from our studies, which harbored a combination of N-terminal alkylation and side-chain lipidation, was equipotent and retained full efficacy at GIPR as the native peptide, while being completely refractory toward DPP4, and was resistant to trypsin. The GIP analogue identified from these studies was further evaluated in vivo and is one of the longest-acting GIPR agonists to date.
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Affiliation(s)
- Kathleen M Sicinski
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Damla Sürmeli
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Jasper Du
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Venkata S Raman
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Vittorio Montanari
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Minhee Lee
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Benjamin N Harwood
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts 02111, United States
| | - Alan S Kopin
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts 02111, United States
| | - Martin Beinborn
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
- Molecular Pharmacology Research Center, Tufts Medical Center, Boston, Massachusetts 02111, United States
| | - Krishna Kumar
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
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Yammine L, Picatoste B, Abdullah N, Leahey RA, Johnson EF, Gómez-Banoy N, Rosselot C, Wen J, Hossain T, Goncalves MD, Lo JC, Garcia-Ocaña A, McGraw TE. Spatiotemporal regulation of GIPR signaling impacts glucose homeostasis as revealed in studies of a common GIPR variant. Mol Metab 2023; 78:101831. [PMID: 37925022 PMCID: PMC10665708 DOI: 10.1016/j.molmet.2023.101831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 10/20/2023] [Accepted: 10/23/2023] [Indexed: 11/06/2023] Open
Abstract
OBJECTIVE Glucose-dependent insulinotropic polypeptide (GIP) has a role in controlling postprandial metabolic tone. In humans, a GIP receptor (GIPR) variant (Q354, rs1800437) is associated with a lower body mass index (BMI) and increased risk for Type 2 Diabetes. To better understand the impacts of GIPR-Q354 on metabolism, it is necessary to study it in an isogeneic background to the predominant GIPR isoform, E354. To accomplish this objective, we used CRISPR-CAS9 editing to generate mouse models of GIPR-Q354 and GIPR-E354. Here we characterize the metabolic effects of GIPR-Q354 variant in a mouse model (GIPR-Q350). METHODS We generated the GIPR-Q350 mice for in vivo studies of metabolic impact of the variant. We isolated pancreatic islets from GIPR-Q350 mice to study insulin secretion ex vivo. We used a β-cell cell line to understand the impact of the GIPR-Q354 variant on the receptor traffic. RESULTS We found that female GIPR-Q350 mice are leaner than littermate controls, and male GIPR-Q350 mice are resistant to diet-induced obesity, in line with the association of the variant with reduced BMI in humans. GIPR-Q350 mice of both sexes are more glucose tolerant and exhibit an increased sensitivity to GIP. Postprandial GIP levels are reduced in GIPR-Q350 mice, revealing feedback regulation that balances the increased sensitivity of GIP target tissues to secretion of GIP from intestinal endocrine cells. The increased GIP sensitivity is recapitulated ex vivo during glucose stimulated insulin secretion assays in islets. Generation of cAMP in islets downstream of GIPR activation is not affected by the Q354 substitution. However, post-activation traffic of GIPR-Q354 variant in β-cells is altered, characterized by enhanced intracellular dwell time and increased localization to the Trans-Golgi Network (TGN). CONCLUSIONS Our data link altered intracellular traffic of the GIPR-Q354 variant with GIP control of metabolism. We propose that this change in spatiotemporal signaling underlies the physiologic effects of GIPR-Q350/4 and GIPR-E350/4 in mice and humans. These findings contribute to a more complete understanding of the impact of GIPR-Q354 variant on glucose homeostasis that could perhaps be leveraged to enhance pharmacologic targeting of GIPR for the treatment of metabolic disease.
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Affiliation(s)
- Lucie Yammine
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Belén Picatoste
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Nazish Abdullah
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Rosemary A Leahey
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Emma F Johnson
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Nicolás Gómez-Banoy
- Weill Center for Metabolic Health and Division of Cardiology, Department of Medicine, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Carolina Rosselot
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Jennifer Wen
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Tahmina Hossain
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | | | - James C Lo
- Weill Center for Metabolic Health and Division of Cardiology, Department of Medicine, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Adolfo Garcia-Ocaña
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Timothy E McGraw
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA; Weill Center for Metabolic Health and Division of Cardiology, Department of Medicine, Weill Cornell Medicine, New York, NY, 10021, USA; Department of Cardiothoracic Surgery, Weill Cornell Medical College, New York, NY, 10065, USA.
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Abstract
INTRODUCTION : Obesity is recognised as a major healthcare challenge. Following years of slow progress in discovery of safe, effective therapies for weight management, recent approval of the glucagon-like peptide 1 receptor (GLP-1R) mimetics, liraglutide and semaglutide, for obesity has generated considerable excitement. It is anticipated these agents will pave the way for application of tirzepatide, a highly effective glucose-dependent insulinotropic polypeptide receptor (GIPR), GLP-1R co-agonist recently approved for management of type 2 diabetes mellitus. AREAS COVERED : Following promising weight loss in obese individuals in Phase III clinical trials, liraglutide and semaglutide were approved for weight management without diabetes. Tirzepatide has attained Fast Track designation for obesity management by the US Food and Drug Association. This narrative review summarises experimental, preclinical and clinical data for these agents and related GLP-1R/GIPR co-agonists, prioritising clinical research published within the last 10 years where possible. EXPERT OPINION : GLP-1R mimetics are often discontinued within 24-months, owing to gastrointestinal side-effects, meaning long-term application of these agents in obesity is questioned. Combined GIPR/GLP-1R agonism appears to induce fewer side-effects, indicating GLP-1R/GIPR co-agonists may be more suitable for enduring obesity management. After years of debate, this GIPR-biased GLP-1R/GIPR co-agonist highlights the therapeutic promise of including GIPR modulation for diabetes and obesity therapy.
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Affiliation(s)
- Ryan A Lafferty
- Diabetes Research Centre, Ulster University, Coleraine, Northern Ireland, BT52 1SA, UK
| | - Peter R Flatt
- Diabetes Research Centre, Ulster University, Coleraine, Northern Ireland, BT52 1SA, UK
| | - Nigel Irwin
- Diabetes Research Centre, Ulster University, Coleraine, Northern Ireland, BT52 1SA, UK
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Wang L. Designing a Dual GLP-1R/GIPR Agonist from Tirzepatide: Comparing Residues Between Tirzepatide, GLP-1, and GIP. Drug Des Devel Ther 2022; 16:1547-1559. [PMID: 35651477 PMCID: PMC9149770 DOI: 10.2147/dddt.s358989] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 05/18/2022] [Indexed: 12/13/2022] Open
Abstract
Improving type 2 diabetes using incretin analogues is becoming increasingly plausible. Currently, tirzepatide is the most promising listed incretin analogue. Here, I briefly explain the evolution of drugs of this kind, analyze the residue discrepancies between tirzepatide and endogenous incretins, summarize some existing strategies for prolonging half-life, and present suggestions for future research, mainly involving biased functions. This review aims to present some useful information for designing a dual glucagon like peptide-1 receptor/glucose-dependent insulinotropic polypeptide receptor agonist. ![]()
Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use: https://youtu.be/yo_lgebnhRo
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Affiliation(s)
- Lijing Wang
- College of Life Sciences and Technology, China Pharmaceutical University, Nanjing, Jiangsu, People's Republic of China
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6
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Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is released from the upper small intestine in response to food intake and contributes to the postprandial control of nutrient disposition, including of sugars and fats. Long neglected as a potential therapeutic target, the GIPR axis has received increasing interest recently, with the emerging data demonstrating the metabolically favorable outcomes of adding GIPR agonism to GLP-1 receptor agonists in people with type 2 diabetes and obesity. This review examines the physiology of the GIP axis, from the mechanisms underlying GIP secretion from the intestine to its action on target tissues and therapeutic development. Expected final online publication date for the Annual Review of Nutrition, Volume 42 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Nunzio Guccio
- MRC Metabolic Diseases Unit, Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom; ,
| | - Fiona M Gribble
- MRC Metabolic Diseases Unit, Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom; ,
| | - Frank Reimann
- MRC Metabolic Diseases Unit, Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom; ,
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7
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Zhang J, Qian XK, Song PF, Li XD, Wang AQ, Huo H, Yao JC, Zhang GM, Zou LW. A high-throughput screening assay for dipeptidyl peptidase-IV inhibitors using human plasma. Anal Methods 2021; 13:2671-2678. [PMID: 34036983 DOI: 10.1039/d1ay00415h] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Dipeptidyl peptidase-IV (DPP-IV) plays a critical role in glucose metabolism and has become an important target for type 2 diabetes mellitus. We previously reported a two-photon fluorescent probe glycyl-prolyl-N-butyl-4-amino-1,8-naphthalimide (GP-BAN) for DPP-IV detection with high specificity and sensitivity. In this study, a high-throughput screening (HTS) method for DPP-IV inhibitors using human plasma as the enzyme source was established and optimized. Further investigations demonstrate that the IC50 value of sitagliptin (listed as the DPP-IV inhibitor) determined with human recombinant DPP-IV (36.22 nM) is very similar to that in human plasma (39.18 nM), and sitagliptin acts as a competitive inhibitor against human plasma DPP-IV-mediated GP-BAN hydrolysis. These results indicate that expensive human recombinant DPP-IV can be replaced by human plasma in this GP-BAN-based assay. On this basis, GP-AMC (commercial probe) was used as a comparison to verify this method, and the catalytic efficacy (Vmax/Km) for GP-AMC (0.09 min-1) hydrolysis in human plasma is lower than that for GP-BAN (0.21 min-1). Further analysis of inhibition kinetics (sitagliptin) and molecular docking (GP-BAN and GP-AMC) showed that GP-BAN has better specificity and affinity for enzymes than GP-AMC. Finally, the optimized method was used for the HTS of DPP-IV inhibitors in 69 natural alkaloids.
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Affiliation(s)
- Jing Zhang
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
| | - Xing-Kai Qian
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
| | - Pei-Fang Song
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
| | - Xiao-Dong Li
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
| | - An-Qi Wang
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
| | - Hong Huo
- Dalian Institute of Chemical Physics, China
| | - Jing-Chun Yao
- State Key Laboratory of Generic Manufacture Technology of Traditional Chinese Medicine, Lunan Pharmaceutical Group Co. Ltd, Linyi, 276006, China.
| | - Gui-Min Zhang
- State Key Laboratory of Generic Manufacture Technology of Traditional Chinese Medicine, Lunan Pharmaceutical Group Co. Ltd, Linyi, 276006, China.
| | - Li-Wei Zou
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
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Craig SL, Gault VA, Shiels CE, Hamscher G, Irwin N. Comparison of independent and combined effects of the neurotensin receptor agonist, JMV-449, and incretin mimetics on pancreatic islet function, glucose homeostasis and appetite control. Biochim Biophys Acta Gen Subj 2021; 1865:129917. [PMID: 33964357 DOI: 10.1016/j.bbagen.2021.129917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/29/2021] [Accepted: 05/03/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND Neurotensin receptor activation augments the biosctivity of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). JMV-449, a C-terminal neurotensin-like fragment with a reduced peptide bond, represents a neurotensin receptor agonist. METHODS The present study assessed the actions of JMV-449 on pancreatic beta-cells alone, and in combination with GIP and GLP-1. Further studies examined the impact of JMV-449 and incretin mimetics on glucose homeostasis and appetite control in mice. RESULTS JMV-449 was resistant to plasma enzyme degradation and induced noticeable dose-dependent insulin-releasing actions in BRIN-BD11 beta-cells. In combination with either GIP or GLP-1, JMV-449 augmented (P < 0.05) the insulinotropic actions of both hormones, as well as enhancing (P < 0.001) insulin secretory activity of both incretin peptides. JMV-449 also increased beta-cell proliferation and induced significant benefits on beta-cell survival in response to cytokine-induced apoptosis. JMV-449 (25 nmol/kg) inhibited (P < 0.05-P < 0.001) food intake in overnight fasted lean mice, and enhanced (P < 0.01) the appetite supressing effects of an enzymatically stable GLP-1 mimetic. When injected co-jointly with glucose, JMV-449 evoked glucose lowering actions, but more interestingly significantly augmented (P < 0.05) the glucose lowering effects of established long-acting GIP and GLP-1 receptor mimetics. In terms of glucose-induced insulin secretion, only GIP receptor signalling was associated with increases in insulin concentrations, and this was not enhanced by JMV-449. CONCLUSION JMV-449 is a neurotensin receptor agonist that positively augments key aspects of the biological action profile of GIP and GLP-1. GENERAL SIGNIFICANCE These observations emphasise the, yet untapped, therapeutic potential of combined neurotensin and incretin receptor signalling for diabetes.
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Affiliation(s)
- S L Craig
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK
| | - V A Gault
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK
| | - C E Shiels
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK
| | - G Hamscher
- Institute of Food Chemistry and Food Biotechnology, Justus Liebig University, Giessen, Germany
| | - N Irwin
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK.
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Chung SI, Kang MY. Oral Administration of Germinated, Pigmented, Giant Embryo Rice ( Oryza sativa L. cv. Keunnunjami) Extract Improves the Lipid and Glucose Metabolisms in High-Fat Diet-Fed Mice. Oxid Med Cell Longev 2021; 2021:8829778. [PMID: 33552386 PMCID: PMC7846407 DOI: 10.1155/2021/8829778] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 12/24/2020] [Accepted: 12/30/2020] [Indexed: 11/18/2022]
Abstract
Obesity is a significant risk factor for chronic diseases. The effect of ethanol extract from germinated Keunnunjami, blackish-purple rice with a giant embryo, compare to ordinary brown rice, on the body weight and lipid and glucose metabolism in high-fat diet-fed mice was analyzed. Mice were fed with a high-fat diet-fed for 3 weeks and then orally administered with either distilled water (HF) or extract (0.25%, w/w) from brown, germinated brown, Keunnunjami, and germinated Keunnunjami rice for 4 weeks. Control mice were fed with a normal diet and orally administered with distilled water. The HF group showed markedly higher body weight and triglyceride, cholesterol, fatty acid, glucose, and insulin levels than the control group. However, the oral administration of rice extracts ameliorated this high-fat diet-induced obesity, hyperlipidemia, and hypoglycemia through the modulation of adipokine production, lipogenic and glucose-regulating enzyme activities, and mRNA expression of genes associated with lipid and glucose metabolism. The germinated Keunnunjami extract exhibited greater hypolipidemic, hypoglycemic, and body weight-lowering effects than the other rice extracts. The results demonstrated that germination could further enhance the physiological properties of rice and that germinated Keunnunjami extract has a strong therapeutic potential against high-fat diet-induced obesity, hyperlipidemia, and hyperglycemia.
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Affiliation(s)
- Soo Im Chung
- International Agricultural Training Center, Kyungpook National University, Daegu 41566, Republic of Korea
- Department of Food Science and Nutrition, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Mi Young Kang
- Department of Food Science and Nutrition, Kyungpook National University, Daegu 41566, Republic of Korea
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Boer GA, Holst JJ. Incretin Hormones and Type 2 Diabetes-Mechanistic Insights and Therapeutic Approaches. Biology (Basel) 2020; 9:biology9120473. [PMID: 33339298 PMCID: PMC7766765 DOI: 10.3390/biology9120473] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/09/2020] [Accepted: 12/10/2020] [Indexed: 02/06/2023]
Abstract
Simple Summary When we ingest a meal, our intestine secretes hormones that are released into the bloodstream. Amongst these hormones are the incretins hormones which stimulate the release of insulin from the pancreas which is essential for the regulation of in particular postprandial glucose concentrations. In patients with type 2 diabetes, the effect of the incretins is diminished. This is thought to contribute importantly to the pathophysiology of the disease. However, in pharmacological amounts, the incretins may still influence insulin secretion and metabolism. Much research has therefore been devoted to the development of incretin-based therapies for type 2 diabetes. These therapies include compounds that strongly resemble the incretins, hereby stimulating their effects as well as inhibitors of the enzymatic degradation of the hormones, thereby increasing the concentration of incretins in the blood. Both therapeutic approaches have been implemented successfully, but research is still ongoing aimed at the development of further optimized therapies. Abstract Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are secreted from the gut upon nutrient stimulation and regulate postprandial metabolism. These hormones are known as classical incretin hormones and are responsible for a major part of postprandial insulin release. The incretin effect is severely reduced in patients with type 2 diabetes, but it was discovered that administration of GLP-1 agonists was capable of normalizing glucose control in these patients. Over the last decades, much research has been focused on the development of incretin-based therapies for type 2 diabetes. These therapies include incretin receptor agonists and inhibitors of the incretin-degrading enzyme dipeptidyl peptidase-4. Especially the development of diverse GLP-1 receptor agonists has shown immense success, whereas studies of GIP monotherapy in patients with type 2 diabetes have consistently been disappointing. Interestingly, both GIP-GLP-1 co-agonists and GIP receptor antagonists administered in combination with GLP-1R agonists appear to be efficient with respect to both weight loss and control of diabetes, although the molecular mechanisms behind these effects remain unknown. This review describes our current knowledge of the two incretin hormones and the development of incretin-based therapies for treatment of type 2 diabetes.
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Affiliation(s)
- Geke Aline Boer
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark;
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Jens Juul Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark;
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
- Correspondence: ; Tel.: +45-2875-7518
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11
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Gasbjerg LS, Bergmann NC, Stensen S, Christensen MB, Rosenkilde MM, Holst JJ, Nauck M, Knop FK. Evaluation of the incretin effect in humans using GIP and GLP-1 receptor antagonists. Peptides 2020; 125:170183. [PMID: 31693916 DOI: 10.1016/j.peptides.2019.170183] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/22/2019] [Accepted: 10/24/2019] [Indexed: 02/07/2023]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) potentiate glucose-induced insulin secretion and are therefore thought to be responsible for the incretin effect. The magnitude of the incretin effect, defined as the fraction of postprandial insulin secretion stimulated by intestinal factors, has been reported to be up to ∼60% in healthy individuals. In several pathological conditions but especially in patients with type 2 diabetes, the incretin effect is severely reduced or even absent. In line with this, the insulinotropic effects of GIP and GLP-1 are impaired in patients with type 2 diabetes, even when administered in supraphysiological doses. In healthy individuals, GIP has been proposed to be the most important incretin hormone of the two, but the individual contribution of the two is difficult to determine. However, using incretin hormone receptor antagonists: the novel GIP receptor antagonist GIP(3-30)NH2 and the widely used GLP-1 receptor antagonist exendin(9-39)NH2, we can now distinguish between the effects of the two hormones. In this review, we present and discuss studies in which the individual contribution of GIP and GLP-1 to the incretin effect in healthy individuals have been estimated and discuss the limitations of using incretin hormone receptor antagonists.
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Affiliation(s)
- 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.
| | - Natasha C Bergmann
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Signe Stensen
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, 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
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael Nauck
- Diabetes Division, St. Josef Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Filip K Knop
- 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; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Steno Diabetes Center Copenhagen, Gentofte, Denmark
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12
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Abstract
The potential application of glucose-dependent insulinotropic polypeptide (gastric inhibitory polypeptide, GIP) in the management of obesity and type 2 diabetes has been controversial. Initial interest in the therapeutic use of GIP was dampened by evidence that its insulinotropic activity was reduced in type 2 diabetes and by reports that it increased glucagon secretion and adipose deposition in non-diabetic individuals. Also, attention was diverted away from GIP by the successful development of glucagon-like peptide-1 (GLP-1) receptor agonists, and a therapeutic strategy for GIP became uncertain when evidence emerged that both inhibition and enhancement of GIP action could prevent or reverse obese non-insulin dependent forms of diabetes in rodents. Species differences in GIP receptor responsiveness complicated the extrapolation of evidence from rodents to humans, but initial clinical studies are investigating the effect of a GIP antagonist in non-diabetic individuals. A therapeutic role for GIP agonists was reconsidered when clinical studies noted that the insulinotropic effect of GIP was increased if near-normal glycaemia was re-established, and GIP was found to have little effect on glucagon secretion or adipose deposition in obese type 2 diabetes patients. This encouraged the development of designer peptides that act as GIP receptor agonists, including chimeric peptides that mimic the incretin partnership of GIP with GLP-1, where the two agents exert complementary and often additive effects to improve glycaemic control and facilitate weight loss. Polyagonist peptides that exert agonism at GIP, GLP-1 and glucagon receptors are also under investigation as potential treatments for obese type 2 diabetes.
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Affiliation(s)
- Clifford J Bailey
- School of Life and Health Sciences, Aston University, B4 7ET, Birmingham, UK.
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13
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Deacon CF. Metabolism of GIP and the contribution of GIP to the glucose-lowering properties of DPP-4 inhibitors. Peptides 2020; 125:170196. [PMID: 31706956 DOI: 10.1016/j.peptides.2019.170196] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 11/05/2019] [Accepted: 11/06/2019] [Indexed: 01/26/2023]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is a gastrointestinal hormone with insulinotropic and glucagonotropic actions, and is believed to be the more physiologically important incretin hormone in healthy humans. Together with the other incretin hormone, glucagon-like peptide-1 (GLP-1), it plays an important role in regulating glucose homeostasis. Both GLP-1 and GIP are substrates of the enzyme dipeptidyl peptidase-4 (DPP-4), and DPP-4 inhibitors, which potentiate their effects on glycaemic control, are now used to treat type 2 diabetes (T2D). This review describes how post-translational processing of the GIP precursor molecule and post-release degradation of the secretory products give rise to multiple isoforms of GIP, some, but not all of which are biologically active, and discusses how this impacts upon their measurement by immunological- and bioassay-based methods. DPP-4 inhibitors reduce degradation of GIP, and although the insulinotropic effects of GIP are impaired in patients with T2D, they can be at least partially restored if glycaemic control is improved. Therefore, given that studies with incretin receptor antagonists indicate that not all of the glucose-lowering effects of DPP-4 inhibition can be accounted for by GLP-1 alone, evidence supports the notion that GIP may play a role in mediating the anti-hyperglycaemic effects of DPP-4 inhibition, while its glucagonotropic actions at lower glucose levels may contribute to the low risk of hypoglycaemia associated with DPP-4 inhibitors.
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Affiliation(s)
- Carolyn F Deacon
- Department of Biomedical Sciences, University of Copenhagen, Panum Institute, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
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14
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Coskun T, Sloop KW, Loghin C, Alsina-Fernandez J, Urva S, Bokvist KB, Cui X, Briere DA, Cabrera O, Roell WC, Kuchibhotla U, Moyers JS, Benson CT, Gimeno RE, D'Alessio DA, Haupt A. LY3298176, a novel dual GIP and GLP-1 receptor agonist for the treatment of type 2 diabetes mellitus: From discovery to clinical proof of concept. Mol Metab 2018; 18:3-14. [PMID: 30473097 PMCID: PMC6308032 DOI: 10.1016/j.molmet.2018.09.009] [Citation(s) in RCA: 355] [Impact Index Per Article: 59.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 09/26/2018] [Accepted: 09/28/2018] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE A novel dual GIP and GLP-1 receptor agonist, LY3298176, was developed to determine whether the metabolic action of GIP adds to the established clinical benefits of selective GLP-1 receptor agonists in type 2 diabetes mellitus (T2DM). METHODS LY3298176 is a fatty acid modified peptide with dual GIP and GLP-1 receptor agonist activity designed for once-weekly subcutaneous administration. LY3298176 was characterised in vitro, using signaling and functional assays in cell lines expressing recombinant or endogenous incretin receptors, and in vivo using body weight, food intake, insulin secretion and glycemic profiles in mice. A Phase 1, randomised, placebo-controlled, double-blind study was comprised of three parts: a single-ascending dose (SAD; doses 0.25-8 mg) and 4-week multiple-ascending dose (MAD; doses 0.5-10 mg) studies in healthy subjects (HS), followed by a 4-week multiple-dose Phase 1 b proof-of-concept (POC; doses 0.5-15 mg) in patients with T2DM (ClinicalTrials.gov no. NCT02759107). Doses higher than 5 mg were attained by titration, dulaglutide (DU) was used as a positive control. The primary objective was to investigate safety and tolerability of LY3298176. RESULTS LY3298176 activated both GIP and GLP-1 receptor signaling in vitro and showed glucose-dependent insulin secretion and improved glucose tolerance by acting on both GIP and GLP-1 receptors in mice. With chronic administration to mice, LY3298176 potently decreased body weight and food intake; these effects were significantly greater than the effects of a GLP-1 receptor agonist. A total of 142 human subjects received at least 1 dose of LY3298176, dulaglutide, or placebo. The PK profile of LY3298176 was investigated over a wide dose range (0.25-15 mg) and supports once-weekly administration. In the Phase 1 b trial of diabetic subjects, LY3298176 doses of 10 mg and 15 mg significantly reduced fasting serum glucose compared to placebo (least square mean [LSM] difference [95% CI]: -49.12 mg/dL [-78.14, -20.12] and -43.15 mg/dL [-73.06, -13.21], respectively). Reductions in body weight were significantly greater with the LY3298176 1.5 mg, 4.5 mg and 10 mg doses versus placebo in MAD HS (LSM difference [95% CI]: -1.75 kg [-3.38, -0.12], -5.09 kg [-6.72, -3.46] and -4.61 kg [-6.21, -3.01], respectively) and doses of 10 mg and 15 mg had a relevant effect in T2DM patients (LSM difference [95% CI]: -2.62 kg [-3.79, -1.45] and -2.07 kg [-3.25, -0.88], respectively. The most frequent side effects reported with LY3298176 were gastrointestinal (vomiting, nausea, decreased appetite, diarrhoea, and abdominal distension) in both HS and patients with T2DM; all were dose-dependent and considered mild to moderate in severity. CONCLUSIONS Based on these results, the pharmacology of LY3298176 translates from preclinical to clinical studies. LY3298176 has the potential to deliver clinically meaningful improvement in glycaemic control and body weight. The data warrant further clinical evaluation of LY3298176 for the treatment of T2DM and potentially obesity.
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Affiliation(s)
- Tamer Coskun
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Kyle W Sloop
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Corina Loghin
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | | | - Shweta Urva
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Krister B Bokvist
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Xuewei Cui
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Daniel A Briere
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Over Cabrera
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - William C Roell
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Uma Kuchibhotla
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Julie S Moyers
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Charles T Benson
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Ruth E Gimeno
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - David A D'Alessio
- Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC, USA
| | - Axel Haupt
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA.
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15
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Hasib A, Ng MT, Khan D, Gault VA, Flatt PR, Irwin N. Characterisation and antidiabetic utility of a novel hybrid peptide, exendin-4/gastrin/xenin-8-Gln. Eur J Pharmacol 2018; 834:126-135. [DOI: 10.1016/j.ejphar.2018.07.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/29/2018] [Accepted: 07/13/2018] [Indexed: 12/14/2022]
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16
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Craig SL, Gault VA, Irwin N. Emerging therapeutic potential for xenin and related peptides in obesity and diabetes. Diabetes Metab Res Rev 2018; 34:e3006. [PMID: 29633491 DOI: 10.1002/dmrr.3006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 03/21/2018] [Accepted: 03/25/2018] [Indexed: 12/16/2022]
Abstract
Xenin-25 is a 25-amino acid peptide hormone co-secreted from the same enteroendocrine K-cell as the incretin peptide glucose-dependent insulinotropic polypeptide. There is no known specific receptor for xenin-25, but studies suggest that at least some biological actions may be mediated through interaction with the neurotensin receptor. Original investigation into the physiological significance of xenin-25 focussed on effects related to gastrointestinal transit and satiety. However, xenin-25 has been demonstrated in pancreatic islets and recently shown to possess actions in relation to the regulation of insulin and glucagon secretion, as well as promoting beta-cell survival. Accordingly, the beneficial impact of xenin-25, and related analogues, has been assessed in animal models of diabetes-obesity. In addition, studies have demonstrated that metabolically active fragment peptides of xenin-25, particularly xenin-8, possess independent therapeutic promise for diabetes, as well as serving as bioactive components for the generation of multi-acting hybrid peptides with antidiabetic potential. This review focuses on continuing developments with xenin compounds in relation to new therapeutic approaches for diabetes-obesity.
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Affiliation(s)
- Sarah L Craig
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Victor A Gault
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
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17
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Abstract
Obesity is a worldwide pandemic, which can be fatal for the most extremely affected individuals. Lifestyle interventions such as diet and exercise are largely ineffective and current anti-obesity medications offer little in the way of significant or sustained weight loss. Bariatric surgery is effective, but largely restricted to only a small subset of extremely obese patients. While the hormonal factors mediating sustained weight loss and remission of diabetes by bariatric surgery remain elusive, a new class of polypharmacological drugs shows potential to shrink the gap in efficacy between a surgery and pharmacology. In essence, this new class of drugs combines the beneficial effects of several independent hormones into a single entity, thereby combining their metabolic efficacy to improve systems metabolism. Such unimolecular drugs include single molecules with agonism at the receptors for glucagon, glucagon-like peptide 1 and the glucose-dependent insulinotropic polypeptide. In preclinical studies, these specially tailored multiagonists outperform both their mono-agonist components and current best in class anti-obesity medications. While clinical trials and vigorous safety analyses are ongoing, these drugs are poised to have a transformative effect in anti-obesity therapy and might hopefully lead the way to a new era in weight-loss pharmacology.
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Affiliation(s)
- S J Brandt
- Institute for Diabetes and ObesityHelmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
- German Center for Diabetes Research (DZD)Neuherberg, Germany
| | - M Kleinert
- Institute for Diabetes and ObesityHelmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
- German Center for Diabetes Research (DZD)Neuherberg, Germany
| | - M H Tschöp
- Institute for Diabetes and ObesityHelmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
- German Center for Diabetes Research (DZD)Neuherberg, Germany
- Division of Metabolic DiseasesTechnische Universität, Munich, Germany
| | - T D Müller
- Institute for Diabetes and ObesityHelmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
- German Center for Diabetes Research (DZD)Neuherberg, Germany
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18
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Pathak NM, Pathak V, Gault VA, McClean S, Irwin N, Flatt PR. Novel dual incretin agonist peptide with antidiabetic and neuroprotective potential. Biochem Pharmacol 2018; 155:264-274. [PMID: 30028989 DOI: 10.1016/j.bcp.2018.07.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/16/2018] [Indexed: 12/11/2022]
Abstract
Glucose-dependent insulinotropic hormone (GIP) and glucagon-like peptide-1 (GLP-1) are incretin hormones that exert an array of beneficial actions on metabolism and cognitive function. GLP-1-based therapeutics have been highly successful in terms of obesity and diabetes management, however GIP therapies have found no clinical utility to date. In the present study we describe, for the first time, the therapeutic effectiveness of a novel GIP/GLP-1 hybrid peptide based on the amino acid sequences of GIP, GLP-1 and the clinically approved GLP-1 mimetic, exendin-4. The hybrid peptide, N-ac(d-Ala2)GIP/GLP-1-exe, was enzymatically stable for up to 12 h when incubated with DPP-4. N-ac(d-Ala2)GIP/GLP-1-exe significantly (P < 0.001) stimulated insulin secretion from BRIN-BD11 cells and isolated mouse islets, and evoked dose-dependent increases (P < 0.001) in cAMP production in both GIP-R and GLP-1-R transfected cells. In mice, injection of the hybrid in combination with glucose significantly (P < 0.001) reduced glucose and increased insulin concentrations, with metabolic actions evident (P < 0.05) 8 h post-injection. Twice-daily injection of N-ac(d-Ala2)GIP/GLP-1-exe to high fat fed (HFF) mice for 28 days significantly (P < 0.05-P < 0.001) reduced body weight, HbA1c, circulating glucose and insulin concentrations. Furthermore, both oral and i.p. glucose tolerance were improved (P < 0.001) and insulin sensitivity enhanced. The hybrid peptide also increased (P < 0.05-P < 0.001) beta cell number, islet area, pancreatic insulin content and islet insulin secretory responsiveness in HFF mice. Finally, N-ac(d-Ala2)GIP/GLP-1-exe treated mice exhibited improved (P < 0.01) recognition memory which was accompanied by enhanced (P < 0.05-P < 0.001) hippocampal neurogenesis, synapse formation and reduced neuronal oxidative stress. These data demonstrate for the first time the beneficial actions of the novel GIP/GLP-1 hybrid, N-ac(d-Ala2)GIP/GLP-1-exe, on glucose homeostasis and memory function in diabetes.
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Affiliation(s)
- N M Pathak
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, UK
| | - V Pathak
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, UK
| | - V A Gault
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, UK
| | - S McClean
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, UK
| | - N Irwin
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, UK.
| | - P R Flatt
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, UK
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19
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Honka H, Koffert J, Kauhanen S, Kudomi N, Hurme S, Mari A, Lindqvist A, Wierup N, Parkkola R, Groop L, Nuutila P. Liver blood dynamics after bariatric surgery: the effects of mixed-meal test and incretin infusions. Endocr Connect 2018; 7:888-896. [PMID: 29941634 PMCID: PMC6063878 DOI: 10.1530/ec-18-0234] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 06/25/2018] [Indexed: 01/18/2023]
Abstract
AIMS/HYPOTHESIS The mechanisms for improved glycemic control after bariatric surgery in subjects with type 2 diabetes (T2D) are not fully known. We hypothesized that dynamic hepatic blood responses to a mixed-meal are changed after bariatric surgery in parallel with an improvement in glucose tolerance. METHODS A total of ten morbidly obese subjects with T2D were recruited to receive a mixed-meal and a glucose-dependent insulinotropic polypeptide (GIP) infusion before and early after (within a median of less than three months) bariatric surgery, and hepatic blood flow and volume (HBV) were measured repeatedly with combined positron emission tomography/MRI. Ten lean non-diabetic individuals served as controls. RESULTS Bariatric surgery leads to a significant decrease in weight, accompanied with an improved β-cell function and glucagon-like peptide 1 (GLP-1) secretion, and a reduction in liver volume. Blood flow in portal vein (PV) was increased by 1.65-fold (P = 0.026) in response to a mixed-meal in subjects after surgery, while HBV decreased in all groups (P < 0.001). When the effect of GIP infusion was tested separately, no change in hepatic arterial and PV flow was observed, but HBV decreased as seen during the mixed-meal test. CONCLUSIONS/INTERPRETATION Early after bariatric surgery, PV flow response to a mixed-meal is augmented, improving digestion and nutrient absorption. GIP influences the post-prandial reduction in HBV thereby diverting blood to the extrahepatic sites.
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Affiliation(s)
- Henri Honka
- Turku PET CentreUniversity of Turku, Turku, Finland
| | - Jukka Koffert
- Turku PET CentreUniversity of Turku, Turku, Finland
- Department of GastroenterologyTurku University Hospital, Turku, Finland
| | - Saila Kauhanen
- Division of Digestive Surgery and UrologyTurku University Hospital, Turku, Finland
| | | | - Saija Hurme
- Department of BiostatisticsUniversity of Turku, Turku, Finland
| | - Andrea Mari
- Institute of NeuroscienceNational Research Council, Padua, Italy
| | - Andreas Lindqvist
- Department of Clinical SciencesLund University Diabetes Centre, Malmö, Sweden
| | - Nils Wierup
- Department of Clinical SciencesLund University Diabetes Centre, Malmö, Sweden
| | - Riitta Parkkola
- Department of RadiologyUniversity of Turku and Turku University Hospital, Turku, Finland
| | - Leif Groop
- Department of Clinical SciencesLund University Diabetes Centre, Malmö, Sweden
| | - Pirjo Nuutila
- Turku PET CentreUniversity of Turku, Turku, Finland
- Department of EndocrinologyTurku University Hospital, Turku, Finland
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20
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Abstract
Dipeptidyl peptidase-4 (DPP-4) inhibitors are now a widely used, safe and efficacious class of antidiabetic drugs, which were developed prospectively using a rational drug design approach based on a thorough understanding of the endocrinology and degradation of glucagon-like peptide-1 (GLP-1). GLP-1 is an intestinal hormone with potent insulinotropic and glucagonostatic effects and can normalise blood glucose levels in patients with type 2 diabetes, but the native peptide is not therapeutically useful because of its inherent metabolic instability. Using the GLP-1/DPP-4 system and type 2 diabetes as an example, this review summarises how knowledge of a peptide's biological effects coupled with an understanding of the pathways involved in its metabolic clearance can be exploited in a rational, step-by-step manner to develop a therapeutic agent, which is effective and well tolerated, and any side effects are minor and largely predictable. Other peptides with metabolic effects which can also be degraded by DPP-4 will be reviewed, and their potential role as additional mediators of the effects of DPP-4 inhibitors will be assessed.
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Affiliation(s)
- Carolyn F Deacon
- Department of Biomedical Sciences, University of Copenhagen, Panum Institute, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
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21
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Hasib A, Ng MT, Khan D, Gault VA, Flatt PR, Irwin N. A novel GLP-1/xenin hybrid peptide improves glucose homeostasis, circulating lipids and restores GIP sensitivity in high fat fed mice. Peptides 2018; 100:202-211. [PMID: 29412820 DOI: 10.1016/j.peptides.2017.10.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 10/24/2017] [Accepted: 10/24/2017] [Indexed: 02/08/2023]
Abstract
Combined modulation of peptide hormone receptors including, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and xenin, have established benefits for the treatment of diabetes. The present study has assessed the biological actions and therapeutic efficacy of a novel exendin-4/xenin-8-Gln hybrid peptide, both alone and in combination with the GIP receptor agonist (DAla2)GIP. Exendin-4/xenin-8-Gln was enzymatically stable and exhibited enhanced insulin secretory actions when compared to its parent peptides. Exendin-4/xenin-8-Gln also possessed ability to potentiate the in vitro actions of GIP. Acute administration of exendin-4/xenin-8-Gln in mice induced appetite suppressive effects, as well as significant and protracted glucose-lowering and insulin secretory actions. Twice daily administration of exendin-4/xenin-8-Gln, alone or in combination with (DAla2)GIP, for 21-days significantly reduced non-fasting glucose and increased circulating insulin levels in high fat fed mice. In addition, all exendin-4/xenin-8-Gln treated mice displayed improved glucose tolerance, insulin sensitivity and metabolic responses to GIP. Combination therapy with (DAla2)GIP did not result in any obvious further benefits. Metabolic improvements in all treatment groups were accompanied by reduced pancreatic beta-cell area and insulin content, suggesting reduced insulin demand. Interestingly, body weight, food intake, circulating glucagon, metabolic rate and amylase activity were unaltered by the treatment regimens. However, all treatment groups, barring (DAla2)GIP alone, exhibited marked reductions in total- and LDL-cholesterol. Furthermore, exendin-4 therapy also reduced circulating triacylglycerol. This study highlights the positive antidiabetic effects of exendin-4/xenin-8-Gln, and suggests that combined modulation of GLP-1 and xenin related signalling pathways represents an exciting treatment option for type 2 diabetes.
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Affiliation(s)
- Annie Hasib
- From the SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Ming T Ng
- From the SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Dawood Khan
- From the SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Victor A Gault
- From the SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- From the SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- From the SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK.
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22
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Li Y, Li L, Hölscher C. Incretin-based therapy for type 2 diabetes mellitus is promising for treating neurodegenerative diseases. Rev Neurosci 2018; 27:689-711. [PMID: 27276528 DOI: 10.1515/revneuro-2016-0018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/02/2016] [Indexed: 12/13/2022]
Abstract
Incretin hormones include glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Due to their promising action on insulinotropic secretion and improving insulin resistance (IR), incretin-based therapies have become a new class of antidiabetic agents for the treatment of type 2 diabetes mellitus (T2DM). Recently, the links between neurodegenerative diseases and T2DM have been identified in a number of studies, which suggested that shared mechanisms, such as insulin dysregulation or IR, may underlie these conditions. Therefore, the effects of incretins in neurodegenerative diseases have been extensively investigated. Protease-resistant long-lasting GLP-1 mimetics such as lixisenatide, liraglutide, and exenatide not only have demonstrated promising effects for treating neurodegenerative diseases in preclinical studies but also have shown first positive results in Alzheimer's disease (AD) and Parkinson's disease (PD) patients in clinical trials. Furthermore, the effects of other related incretin-based therapies such as GIP agonists, dipeptidyl peptidase-IV (DPP-IV) inhibitors, oxyntomodulin (OXM), dual GLP-1/GIP, and triple GLP-1/GIP/glucagon receptor agonists on neurodegenerative diseases have been tested in preclinical studies. Incretin-based therapies are a promising approach for treating neurodegenerative diseases.
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23
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Nørregaard PK, Deryabina MA, Tofteng Shelton P, Fog JU, Daugaard JR, Eriksson PO, Larsen LF, Jessen L. A novel GIP analogue, ZP4165, enhances glucagon-like peptide-1-induced body weight loss and improves glycaemic control in rodents. Diabetes Obes Metab 2018; 20:60-68. [PMID: 28598027 DOI: 10.1111/dom.13034] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 06/02/2017] [Accepted: 06/02/2017] [Indexed: 01/17/2023]
Abstract
AIM To investigate the effects of the novel glucose-dependent insulinotropic polypeptide (GIP) analogue, ZP4165, on body weight and glycaemic control in rodents, and to investigate if ZP4165 modulates the anti-obesity and anti-hyperglycaemic effects of a glucagon-like peptide-1 (GLP-1) agonist (liraglutide). METHODS The acute insulinotropic effect of ZP4165 was investigated in rats during an oral glucose tolerance test. The long-term effects of ZP4165 on body weight and glycaemic control, either alone or in combination with liraglutide, were assessed in diet-induced obese mice and diabetic db/db mice. RESULTS ZP4165 showed insulinotropic action in rats. The GIP analogue did not alter the body weight of obese mice but enhanced GLP-1-induced weight loss. In diabetic mice, 4 weeks' dosing with ZP4165 reduced glycated haemoglobin levels vs vehicle by an extent similar to the GLP-1 agonist. CONCLUSIONS ZP4165 potentiated the anti-obesity effect of a GLP-1 agonist in obese mice and improved glycaemic control in diabetic mice. These studies support further investigation of dual-incretin therapy as a more effective treatment option than mono GLP-1 medication for type 2 diabetes mellitus and obesity.
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MESH Headings
- Animals
- Anti-Obesity Agents/blood
- Anti-Obesity Agents/pharmacokinetics
- Anti-Obesity Agents/pharmacology
- Anti-Obesity Agents/therapeutic use
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/metabolism
- Drug Design
- Drug Therapy, Combination
- Gastric Inhibitory Polypeptide/analogs & derivatives
- Gastric Inhibitory Polypeptide/pharmacokinetics
- Gastric Inhibitory Polypeptide/pharmacology
- Gastric Inhibitory Polypeptide/therapeutic use
- Glucagon-Like Peptide-1 Receptor/agonists
- Glucagon-Like Peptide-1 Receptor/genetics
- Glucagon-Like Peptide-1 Receptor/metabolism
- HEK293 Cells
- Half-Life
- Humans
- Hyperglycemia/prevention & control
- Hypoglycemic Agents/blood
- Hypoglycemic Agents/pharmacokinetics
- Hypoglycemic Agents/pharmacology
- Hypoglycemic Agents/therapeutic use
- Incretins/pharmacology
- Incretins/therapeutic use
- Liraglutide/pharmacology
- Liraglutide/therapeutic use
- Male
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Obesity/blood
- Obesity/drug therapy
- Obesity/metabolism
- Rats, Sprague-Dawley
- Receptors, Gastrointestinal Hormone/agonists
- Receptors, Gastrointestinal Hormone/genetics
- Receptors, Gastrointestinal Hormone/metabolism
- Receptors, Glucagon/genetics
- Receptors, Glucagon/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Weight Loss/drug effects
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24
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Hosoda Y, Okahara F, Mori T, Deguchi J, Ota N, Osaki N, Shimotoyodome A. Dietary steamed wheat bran increases postprandial fat oxidation in association with a reduced blood glucose-dependent insulinotropic polypeptide response in mice. Food Nutr Res 2017; 61:1361778. [PMID: 28970776 PMCID: PMC5614337 DOI: 10.1080/16546628.2017.1361778] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 07/19/2017] [Indexed: 10/25/2022] Open
Abstract
Obesity is a global epidemic associated with a higher risk of cardiovascular disease and metabolic disorders, such as type 2 diabetes. Previous studies demonstrated that chronic feeding of steamed wheat bran (WB) decreases obesity. To clarify the underlying mechanism and the responsible component for the anti-obesity effects of steamed WB, we investigated the effects of dietary steamed WB and arabinoxylan on postprandial energy metabolism and blood variables. Overnight-fasted male C57BL/6J mice were fed an isocaloric diet with or without steamed WB (30%). Energy metabolism was evaluated using an indirect calorimeter, and plasma glucose, insulin, and glucose-dependent insulinotropic polypeptide (GIP) levels were measured for 120 min after feeding. We similarly investigated the effect of arabinoxylan, a major component of steamed WB. Mice fed the WB diet had higher postprandial fat oxidation and a lower blood GIP response compared with mice fed the control diet. Mice fed the arabinoxylan diet exhibited a dose-dependent postprandial blood GIP response; increasing the arabinoxylan content in the diet led to a lower postprandial blood GIP response. The arabinoxylan-fed mice also had higher fat oxidation and energy expenditure compared with the control mice. In conclusion, the findings of the present study revealed that dietary steamed WB increases fat oxidation in mice. Increased fat oxidation may have a significant role in the anti-obesity effects of steamed WB. The postprandial effects of steamed WB are due to arabinoxylan, a major component of WB. The reduction of the postprandial blood GIP response may be responsible for the increase in postprandial fat utilization after feeding on a diet containing steamed WB and arabinoxylan.
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Affiliation(s)
- Yayoi Hosoda
- Biological Science Laboratories, Kao Corporation, Tochigi, Japan
| | - Fumiaki Okahara
- Biological Science Laboratories, Kao Corporation, Tochigi, Japan
| | - Takuya Mori
- Biological Science Laboratories, Kao Corporation, Tochigi, Japan
| | - Jun Deguchi
- Biological Science Laboratories, Kao Corporation, Tochigi, Japan
| | - Noriyasu Ota
- Biological Science Laboratories, Kao Corporation, Tochigi, Japan
| | - Noriko Osaki
- Biological Science Laboratories, Kao Corporation, Tochigi, Japan
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25
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Muscogiuri G, Balercia G, Barrea L, Cignarelli A, Giorgino F, Holst JJ, Laudisio D, Orio F, Tirabassi G, Colao A. Gut: A key player in the pathogenesis of type 2 diabetes? Crit Rev Food Sci Nutr 2017; 58:1294-1309. [PMID: 27892685 DOI: 10.1080/10408398.2016.1252712] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The gut regulates glucose and energy homeostasis; thus, the presence of ingested nutrients into the gut activates sensing mechanisms that affect both glucose homeostasis and regulate food intake. Increasing evidence suggest that gut may also play a key role in the pathogenesis of type 2 diabetes which may be related to both the intestinal microbiological profile and patterns of gut hormones secretion. Intestinal microbiota includes trillions of microorganisms but its composition and function may be adversely affected in type 2 diabetes. The intestinal microbiota may be responsible of the secretion of molecules that may impair insulin secretion/action. At the same time, intestinal milieu regulates the secretion of hormones such as GLP-1, GIP, ghrelin, gastrin, somatostatin, CCK, serotonin, peptide YY, GLP-2, all of which importantly influence metabolism in general and in particular glucose metabolism. Thus, the aim of this paper is to review the current evidence on the role of the gut in the pathogenesis of type 2 diabetes, taking into account both hormonal and microbiological aspects.
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Affiliation(s)
| | - Giancarlo Balercia
- b Division of Endocrinology, Department of Clinical and Molecular Sciences , Umberto I Hospital, Polytechnic University of Marche , Ancona , Italy
| | | | - Angelo Cignarelli
- c Department of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology, Andrology, and Metabolic Diseases , University of Bari Aldo Moro , Bari , Italy
| | - Francesco Giorgino
- c Department of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology, Andrology, and Metabolic Diseases , University of Bari Aldo Moro , Bari , Italy
| | - Jens J Holst
- d NNF Center for Basic Metabolic Research and Department of Biomedical Sciences , Panum Institute, University of Copenhagen, Copenhagen , Denmark
| | | | - Francesco Orio
- e Endocrinology, Department of Sports Science and Wellness , "Parthenope" University Naples , Naples , Italy
| | - Giacomo Tirabassi
- b Division of Endocrinology, Department of Clinical and Molecular Sciences , Umberto I Hospital, Polytechnic University of Marche , Ancona , Italy
| | - Annamaria Colao
- f Department of Clinical Medicine and Surgery , "Federico II" University of Naples , Naples , Italy
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26
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Hasib A, Ng MT, Gault VA, Khan D, Parthsarathy V, Flatt PR, Irwin N. An enzymatically stable GIP/xenin hybrid peptide restores GIP sensitivity, enhances beta cell function and improves glucose homeostasis in high-fat-fed mice. Diabetologia 2017; 60:541-552. [PMID: 28004148 PMCID: PMC6518372 DOI: 10.1007/s00125-016-4186-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 11/29/2016] [Indexed: 12/12/2022]
Abstract
AIMS/HYPOTHESIS Glucose-dependent insulinotropic polypeptide (GIP) and xenin, regulatory gut hormones secreted from enteroendocrine K cells, exert important effects on metabolism. In addition, xenin potentiates the biological actions of GIP. The present study assessed the actions and therapeutic utility of a (DAla2)GIP/xenin-8-Gln hybrid peptide, in comparison with the parent peptides (DAla2)GIP and xenin-8-Gln. METHODS Following confirmation of enzymatic stability, insulin secretory activity of (DAla2)GIP/xenin-8-Gln was assessed in BRIN-BD11 beta cells. Acute and persistent glucose-lowering and insulin-releasing effects were then examined in vivo. Finally, the metabolic benefits of twice daily injection of (DAla2)GIP/xenin-8-Gln was determined in high-fat-fed mice. RESULTS All peptides significantly (p < 0.05 to p < 0.001) enhanced in vitro insulin secretion from pancreatic clonal BRIN-BD11 cells, with xenin (and particularly GIP)-related signalling pathways, being important for this action. Administration of (DAla2)GIP or (DAla2)GIP/xenin-8-Gln in combination with glucose significantly (p < 0.05) lowered blood glucose and increased plasma insulin in mice, with a protracted response of up to 4 h. All treatments elicited appetite-suppressive effects (p < 0.05), particularly (DAla2)GIP/xenin-8-Gln and xenin-8-Gln at elevated doses of 250 nmol/kg. Twice-daily administration of (DAla2)GIP/xenin-8-Gln or (DAla2)GIP for 21 days to high-fat-fed mice returned circulating blood glucose to lean control levels. In addition, (DAla2)GIP/xenin-8-Gln treatment significantly (p < 0.05) reduced glycaemic levels during a 24 h glucose profile assessment. Neither of the treatment regimens had an effect on body weight, energy intake or circulating insulin concentrations. However, insulin sensitivity was significantly (p < 0.001) improved by both treatments. Interestingly, GIP-mediated glucose-lowering (p < 0.05) and insulin-releasing (p < 0.05 to p < 0.01) effects were substantially improved by (DAla2)GIP and (DAla2)GIP/xenin-8-Gln treatment. Pancreatic islet and beta cell area (p < 0.001), as well as pancreatic insulin content (p < 0.05), were augmented in (DAla2)GIP/xenin-8-Gln-treated mice, related to enhanced proliferation and decreased apoptosis of beta cells, whereas (DAla2)GIP evoked increases (p < 0.05 to p < 0.01) in islet number. CONCLUSIONS/INTERPRETATION These studies highlight the clear potential of GIP/xenin hybrids for the treatment of type 2 diabetes.
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Affiliation(s)
- Annie Hasib
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
| | - Ming T Ng
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
| | - Victor A Gault
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
| | - Dawood Khan
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
| | - Vadivel Parthsarathy
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK.
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27
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Shimazu-Kuwahara S, Harada N, Yamane S, Joo E, Sankoda A, Kieffer TJ, Inagaki N. Attenuated secretion of glucose-dependent insulinotropic polypeptide (GIP) does not alleviate hyperphagic obesity and insulin resistance in ob/ob mice. Mol Metab 2017; 6:288-94. [PMID: 28271035 DOI: 10.1016/j.molmet.2017.01.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 01/11/2017] [Accepted: 01/16/2017] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVE Glucose-dependent insulinotropic polypeptide (GIP) is released during meals and promotes nutrient uptake and storage. GIP receptor knockout mice are protected from diet induced weight gain and thus GIP antagonists have been proposed as a treatment for obesity. In this study, we assessed the role of GIP in hyperphagia induced obesity and metabolic abnormalities in leptin deficient (Lepob/ob) mice. METHODS We crossbred GIP-GFP knock-in homozygous mice (GIPgfp/gfp) that have complete GIP knockout, and mice heterozygous for the ob mutation (Lepob/+) mice to generate Lepob/+/GIP+/+, Lepob/ob/GIP+/+, and Lepob/ob/GIPgfp/gfp mice. Male animals were weighed weekly and both oral glucose and insulin tolerance testing were performed to assess glucose homeostasis and circulating profiles of GIP and insulin. Body composition was evaluated by computerized tomography (CT) scan and analyses of indirect calorimetry and locomotor activity were performed. RESULTS Postprandial GIP levels were markedly elevated in Lepob/ob/GIP+/+ mice compared to Lepob/+/GIP+/+ controls and were undetectable in Lepob/ob/GIPgfp/gfp mice. Insulin levels were equivalently elevated in both Lepob/ob/GIP+/+ and Lepob/ob/GIPgfp/gfp mice compared to controls at 8 weeks of age but the hyperinsulinemia was marginally reduced in Lepob/ob/GIPgfp/gfp by 21 weeks, in association with amelioration of glucose intolerance. Both Lepob/ob/GIP+/+ and Lepob/ob/GIPgfp/gfp mice remained equivalently insulin resistant. Body weight gain and subcutaneous and visceral fat volume of both Lepob/ob/GIP+/+ and Lepob/ob/GIPgfp/gfp mice were significantly higher than that of Lepob/+/GIP+/+ mice, while no significant differences were seen between Lepob/ob/GIP+/+ and Lepob/ob/GIPgfp/gfp mice. Locomotor activity and energy expenditure were decreased in both Lepob/ob/GIP+/+ and Lepob/ob/GIPgfp/gfp mice compared to control Lepob/+/GIP+/+ mice, while no significant differences were seen between Lepob/ob/GIP+/+ and Lepob/ob/GIPgfp/gfp mice. There was no significant difference in fat oxidation among the three groups. Fat content in liver was significantly lower in Lepob/ob/GIPgfp/gfp compared to Lepob/ob/GIP+/+ mice, while that of control Lepob/+/GIP+/+ mice was the lowest. CONCLUSIONS Our results indicate that GIP knockout does not prevent excess weight gain and metabolic derangement in hyperphagic leptin deficient mice.
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28
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Mabilleau G, Perrot R, Mieczkowska A, Boni S, Flatt PR, Irwin N, Chappard D. Glucose-dependent insulinotropic polypeptide (GIP) dose-dependently reduces osteoclast differentiation and resorption. Bone 2016; 91:102-12. [PMID: 27451082 DOI: 10.1016/j.bone.2016.07.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 06/23/2016] [Accepted: 07/18/2016] [Indexed: 12/13/2022]
Abstract
A role for glucose-dependent insulinotropic polypeptide (GIP) in controlling bone resorption has been suspected. However uncertainty remains to identify whether GIP act directly on osteoclasts. The aim of the present study were (i) to identify in different osteoclast differentiation models (human peripheral blood mononuclear cells-PBMC, murine bone marrow macrophage-BMM and murine Raw 264.7 cells) whether GIP was capable of reducing osteoclast formation and resorption; (ii) ascertain whether the highly potent GIP analogue N-AcGIP was capable of inducing a response at lower concentrations and (iii) to decipher the molecular mechanisms responsible for such effects. [d-Ala(2)]-GIP dose-dependently reduced osteoclast formation at concentration as low as 1nM in human PBMC and 10nM in murine BMM cultures. Furthermore, [d-Ala(2)]-GIP also reduced the extent of osteoclast resorption at concentration as low as 1nM in human PBMC and murine BMM cultures. The mechanism of action of [d-Ala(2)]-GIP appeared to be mediated by reduction in intracellular calcium concentration and oscillation that subsequently inhibited calcineurin activity and NFATc1 nuclear translocation. The potency of the highly potent N-AcGIP was determined and highlighted an effect on osteoclast formation and resorption at concentration ten times lower than observed with [d-Ala(2)]-GIP in vitro. Furthermore, N-AcGIP was also capable of reducing the number of osteoclast in ovariectomized mice as well as the circulating level of type I collagen C-telopeptide. Pharmacological concentrations required for reducing osteoclast formation and resorption provide the impetus to design and exploit enzymatically stable GIP analogues for the treatment of bone resorption disorders in humans.
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Affiliation(s)
- Guillaume Mabilleau
- GEROM Groupe Etudes Remodelage Osseux et bioMatériaux - LHEA, IRIS-IBS Institut de Biologie en Santé, University of Angers, 49933 ANGERS Cedex, France; SCIAM, Service Commun d'Imagerie et Analyses Microscopiques, IRIS-IBS Institut de Biologie en Santé, University of Angers, 49933 ANGERS Cedex, France.
| | - Rodolphe Perrot
- SCIAM, Service Commun d'Imagerie et Analyses Microscopiques, IRIS-IBS Institut de Biologie en Santé, University of Angers, 49933 ANGERS Cedex, France
| | - Aleksandra Mieczkowska
- GEROM Groupe Etudes Remodelage Osseux et bioMatériaux - LHEA, IRIS-IBS Institut de Biologie en Santé, University of Angers, 49933 ANGERS Cedex, France
| | - Sébastien Boni
- Lentivec, IRIS-IBS Institut de Biologie en Santé, University of Angers, 49933 ANGERS Cedex, France
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, Diabetes Research Group, Biomedical Sciences Research Institute, University of Ulster, BT52 1SA Coleraine, United Kingdom
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, Diabetes Research Group, Biomedical Sciences Research Institute, University of Ulster, BT52 1SA Coleraine, United Kingdom
| | - Daniel Chappard
- GEROM Groupe Etudes Remodelage Osseux et bioMatériaux - LHEA, IRIS-IBS Institut de Biologie en Santé, University of Angers, 49933 ANGERS Cedex, France; SCIAM, Service Commun d'Imagerie et Analyses Microscopiques, IRIS-IBS Institut de Biologie en Santé, University of Angers, 49933 ANGERS Cedex, France
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29
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Sekar R, Singh K, Arokiaraj AWR, Chow BKC. Pharmacological Actions of Glucagon-Like Peptide-1, Gastric Inhibitory Polypeptide, and Glucagon. Int Rev Cell Mol Biol 2016; 326:279-341. [PMID: 27572131 DOI: 10.1016/bs.ircmb.2016.05.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Glucagon family of peptide hormones is a group of structurally related brain-gut peptides that exert their pleiotropic actions through interactions with unique members of class B1 G protein-coupled receptors (GPCRs). They are key regulators of hormonal homeostasis and are important drug targets for metabolic disorders such as type-2 diabetes mellitus (T2DM), obesity, and dysregulations of the nervous systems such as migraine, anxiety, depression, neurodegeneration, psychiatric disorders, and cardiovascular diseases. The current review aims to provide a detailed overview of the current understanding of the pharmacological actions and therapeutic advances of three members within this family including glucagon-like peptide-1 (GLP-1), gastric inhibitory polypeptide (GIP), and glucagon.
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Affiliation(s)
- R Sekar
- School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - K Singh
- School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - A W R Arokiaraj
- School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - B K C Chow
- School of Biological Sciences, University of Hong Kong, Hong Kong, China.
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30
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Mansur SA, Mieczkowska A, Flatt PR, Bouvard B, Chappard D, Irwin N, Mabilleau G. A new stable GIP-Oxyntomodulin hybrid peptide improved bone strength both at the organ and tissue levels in genetically-inherited type 2 diabetes mellitus. Bone 2016; 87:102-13. [PMID: 27062994 DOI: 10.1016/j.bone.2016.04.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 03/30/2016] [Accepted: 04/04/2016] [Indexed: 12/25/2022]
Abstract
Obesity and type 2 diabetes mellitus (T2DM) progress worldwide with detrimental effects on several physiological systems including bone tissue mainly by affecting bone quality. Several gut hormones analogues have been proven potent in ameliorating bone quality. In the present study, we used the leptin receptor-deficient db/db mice as a model of obesity and severe T2DM to assess the extent of bone quality alterations at the organ and tissue levels. We also examined the beneficial effects of gut hormone therapy in this model by using a new triple agonist ([d-Ala(2)]GIP-Oxm) active at the GIP, GLP-1 and glucagon receptors. As expected, db/db mice presented with dramatic alterations of bone strength at the organ level associated with deterioration of trabecular and cortical microarchitectures and an augmentation in osteoclast numbers. At the tissue level, these animals presented also with alterations of bone strength (reduced hardness, indentation modulus and dissipated energy) with modifications of tissue mineral distribution, collagen glycation and collagen maturity. The use of [d-Ala(2)]GIP-Oxm considerably improved bone strength at the organ level with modest effects on trabecular microarchitecture. At the tissue level, [d-Ala(2)]GIP-Oxm ameliorated bone strength reductions with positive effects on collagen glycation and collagen maturity. This study provides support for including gut hormone analogues as possible new therapeutic strategies for improving bone quality in bone complications associated to T2DM.
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Affiliation(s)
- Sity Aishah Mansur
- Universiti Tun Hussein Onn Malaysia, Johor, Malaysia; School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, United Kingdom
| | - Aleksandra Mieczkowska
- GEROM Groupe Etudes Remodelage Osseux et bioMatériaux - LHEA, IRIS-IBS Institut de Biologie en Santé, CHU d'Angers, LUNAM Université, 49933 ANGERS Cedex, France
| | - Peter R Flatt
- Universiti Tun Hussein Onn Malaysia, Johor, Malaysia
| | - Beatrice Bouvard
- GEROM Groupe Etudes Remodelage Osseux et bioMatériaux - LHEA, IRIS-IBS Institut de Biologie en Santé, CHU d'Angers, LUNAM Université, 49933 ANGERS Cedex, France
| | - Daniel Chappard
- GEROM Groupe Etudes Remodelage Osseux et bioMatériaux - LHEA, IRIS-IBS Institut de Biologie en Santé, CHU d'Angers, LUNAM Université, 49933 ANGERS Cedex, France; SCIAM, Service Commun d'Imagerie et Analyses Microscopiques, IRIS-IBS Institut de Biologie en Santé, CHU d'Angers, LUNAM Université, 49933 ANGERS Cedex, France
| | - Nigel Irwin
- Universiti Tun Hussein Onn Malaysia, Johor, Malaysia
| | - Guillaume Mabilleau
- GEROM Groupe Etudes Remodelage Osseux et bioMatériaux - LHEA, IRIS-IBS Institut de Biologie en Santé, CHU d'Angers, LUNAM Université, 49933 ANGERS Cedex, France; SCIAM, Service Commun d'Imagerie et Analyses Microscopiques, IRIS-IBS Institut de Biologie en Santé, CHU d'Angers, LUNAM Université, 49933 ANGERS Cedex, France.
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31
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McShane LM, Irwin N, O'Flynn D, Franklin ZJ, Hewage CM, O'Harte FPM. Glucagon receptor antagonist and GIP agonist combination for diet-induced obese mice. J Endocrinol 2016; 229:319-30. [PMID: 27098830 DOI: 10.1530/joe-15-0463] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 04/19/2016] [Indexed: 12/13/2022]
Abstract
Ablation of glucagon receptor signaling represents a potential treatment option for type 2 diabetes (T2DM). Additionally, activation of glucose-dependent insulinotropic polypeptide (GIP) receptor signaling also holds therapeutic promise for T2DM. Therefore, this study examined both independent and combined metabolic actions of desHis(1)Pro(4)Glu(9)(Lys(12)PAL)-glucagon (glucagon receptor antagonist) and d-Ala(2)GIP (GIP receptor agonist) in diet-induced obese mice. Glucagon receptor binding has been linked to alpha-helical structure and desHis(1)Pro(4)Glu(9)(Lys(12)PAL)-glucagon displayed enhanced alpha-helical content compared with native glucagon. In clonal pancreatic BRIN-BD11 beta-cells, desHis(1)Pro(4)Glu(9)(Lys(12)PAL)-glucagon was devoid of any insulinotropic or cAMP-generating actions, and did not impede d-Ala(2)GIP-mediated (P<0.01 to P<0.001) effects on insulin and cAMP production. Twice-daily injection of desHis(1)Pro(4)Glu(9)(Lys(12)PAL)-glucagon or d-Ala(2)GIP alone, and in combination, in high-fat-fed mice failed to affect body weight or energy intake. Circulating blood glucose levels were significantly (P<0.05 to P<0.01) decreased by all treatments regimens, with plasma and pancreatic insulin elevated (P<0.05 to P<0.001) in all mice receiving d-Ala(2)GIP. Interestingly, plasma glucagon concentrations were decreased (P<0.05) by sustained glucagon inhibition (day 28), but increased (P<0.05) by d-Ala(2)GIP therapy, with a combined treatment resulting in glucagon concentration similar to saline controls. All treatments improved (P<0.01) intraperitoneal and oral glucose tolerance, and peripheral insulin sensitivity. d-Ala(2)GIP-treated mice showed increased glucose-induced insulin secretion in response to intraperitoneal and oral glucose. Metabolic rate and ambulatory locomotor activity were increased (P<0.05 to P<0.001) in all desHis(1)Pro(4)Glu(9)(Lys(12)PAL)-glucagon-treated mice. These studies highlight the potential of glucagon receptor inhibition alone, and in combination with GIP receptor activation, for T2DM treatment.
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Affiliation(s)
- L M McShane
- SAAD Centre for Pharmacy and DiabetesUniversity of Ulster, Coleraine, Northern Ireland, UK
| | - N Irwin
- SAAD Centre for Pharmacy and DiabetesUniversity of Ulster, Coleraine, Northern Ireland, UK
| | - D O'Flynn
- Conway Institute of Biomolecular and Biomedical ResearchUCD, Belfield, Dublin 4, Ireland
| | - Z J Franklin
- SAAD Centre for Pharmacy and DiabetesUniversity of Ulster, Coleraine, Northern Ireland, UK
| | - C M Hewage
- Conway Institute of Biomolecular and Biomedical ResearchUCD, Belfield, Dublin 4, Ireland
| | - F P M O'Harte
- SAAD Centre for Pharmacy and DiabetesUniversity of Ulster, Coleraine, Northern Ireland, UK
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Fridlyand LE, Philipson LH. Pancreatic Beta Cell G-Protein Coupled Receptors and Second Messenger Interactions: A Systems Biology Computational Analysis. PLoS One 2016; 11:e0152869. [PMID: 27138453 DOI: 10.1371/journal.pone.0152869] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 03/21/2016] [Indexed: 12/17/2022] Open
Abstract
Insulin secretory in pancreatic beta-cells responses to nutrient stimuli and hormonal modulators include multiple messengers and signaling pathways with complex interdependencies. Here we present a computational model that incorporates recent data on glucose metabolism, plasma membrane potential, G-protein-coupled-receptors (GPCR), cytoplasmic and endoplasmic reticulum calcium dynamics, cAMP and phospholipase C pathways that regulate interactions between second messengers in pancreatic beta-cells. The values of key model parameters were inferred from published experimental data. The model gives a reasonable fit to important aspects of experimentally measured metabolic and second messenger concentrations and provides a framework for analyzing the role of metabolic, hormones and neurotransmitters changes on insulin secretion. Our analysis of the dynamic data provides support for the hypothesis that activation of Ca2+-dependent adenylyl cyclases play a critical role in modulating the effects of glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and catecholamines. The regulatory properties of adenylyl cyclase isoforms determine fluctuations in cytoplasmic cAMP concentration and reveal a synergistic action of glucose, GLP-1 and GIP on insulin secretion. On the other hand, the regulatory properties of phospholipase C isoforms determine the interaction of glucose, acetylcholine and free fatty acids (FFA) (that act through the FFA receptors) on insulin secretion. We found that a combination of GPCR agonists activating different messenger pathways can stimulate insulin secretion more effectively than a combination of GPCR agonists for a single pathway. This analysis also suggests that the activators of GLP-1, GIP and FFA receptors may have a relatively low risk of hypoglycemia in fasting conditions whereas an activator of muscarinic receptors can increase this risk. This computational analysis demonstrates that study of second messenger pathway interactions will improve understanding of critical regulatory sites, how different GPCRs interact and pharmacological targets for modulating insulin secretion in type 2 diabetes.
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Finan B, Müller TD, Clemmensen C, Perez-Tilve D, DiMarchi RD, Tschöp MH. Reappraisal of GIP Pharmacology for Metabolic Diseases. Trends Mol Med 2016; 22:359-376. [DOI: 10.1016/j.molmed.2016.03.005] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/15/2016] [Accepted: 03/17/2016] [Indexed: 12/31/2022]
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Symonds ME, Dellschaft N, Pope M, Birtwistle M, Alagal R, Keisler D, Budge H. Developmental programming, adiposity, and reproduction in ruminants. Theriogenology 2016; 86:120-9. [PMID: 27173959 DOI: 10.1016/j.theriogenology.2016.04.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 02/29/2016] [Accepted: 03/14/2016] [Indexed: 01/21/2023]
Abstract
Although sheep have been widely adopted as an animal model for examining the timing of nutritional interventions through pregnancy on the short- and long-term outcomes, only modest programming effects have been seen. This is due in part to the mismatch in numbers of twins and singletons between study groups as well as unequal numbers of males and females. Placental growth differs between singleton and twin pregnancies which can result in different body composition in the offspring. One tissue that is especially affected is adipose tissue which in the sheep fetus is primarily located around the kidneys and heart plus the sternal/neck region. Its main role is the rapid generation of heat due to activation of the brown adipose tissue-specific uncoupling protein 1 at birth. The fetal adipose tissue response to suboptimal maternal food intake at defined stages of development differs between the perirenal abdominal and pericardial depots, with the latter being more sensitive. Fetal adipose tissue growth may be mediated in part by changes in leptin status of the mother which are paralleled in the fetus. Then, over the first month of life plasma leptin is higher in females than males despite similar adiposity, when fat is the fastest growing tissue with the sternal/neck depot retaining uncoupling protein 1, whereas other depots do not. Future studies should take into account the respective effects of fetal number and sex to provide more detailed insights into the mechanisms by which adipose and related tissues can be programmed in utero.
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Affiliation(s)
- M E Symonds
- Early Life Research Unit, Academic Division of Child Health, Obstetrics & Gynaecology, School of Medicine, Queen's Medical Centre, The University of Nottingham, Nottingham, UK.
| | - N Dellschaft
- Early Life Research Unit, Academic Division of Child Health, Obstetrics & Gynaecology, School of Medicine, Queen's Medical Centre, The University of Nottingham, Nottingham, UK
| | - M Pope
- Early Life Research Unit, Academic Division of Child Health, Obstetrics & Gynaecology, School of Medicine, Queen's Medical Centre, The University of Nottingham, Nottingham, UK
| | - M Birtwistle
- Early Life Research Unit, Academic Division of Child Health, Obstetrics & Gynaecology, School of Medicine, Queen's Medical Centre, The University of Nottingham, Nottingham, UK
| | - R Alagal
- Early Life Research Unit, Academic Division of Child Health, Obstetrics & Gynaecology, School of Medicine, Queen's Medical Centre, The University of Nottingham, Nottingham, UK
| | - D Keisler
- Department of Animal Science, University of Missouri, Columbia, Missouri, USA
| | - H Budge
- Early Life Research Unit, Academic Division of Child Health, Obstetrics & Gynaecology, School of Medicine, Queen's Medical Centre, The University of Nottingham, Nottingham, UK
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Pederson RA, McIntosh CH. Discovery of gastric inhibitory polypeptide and its subsequent fate: Personal reflections. J Diabetes Investig 2016; 7 Suppl 1:4-7. [PMID: 27186348 PMCID: PMC4854497 DOI: 10.1111/jdi.12480] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 12/22/2015] [Accepted: 01/06/2016] [Indexed: 01/04/2023] Open
Abstract
The present review focuses initially on experimental studies that were designed to identify acid inhibitory factors, referred to as 'enterogastrones,' that ultimately led to the isolation of gastric inhibitory polypeptide (GIP), a 42-amino acid polypeptide. GIP was shown to inhibit acid secretion in animal models, as well as stimulating gastric somatostatin secretion. However, its role in human gastric physiology is unclear. Further studies showed that GIP strongly stimulated the secretion of insulin, in the presence of elevated glucose, and this 'incretin' action is now considered to be its most important; an alternative for the GIP acronym, glucose-dependent insulinotropic polypeptide, was therefore introduced. In the 1970s, GIP purified by conventional chromatography was shown by high-performance liquid chromatography to consist largely of GIP 1-42 and GIP 3-42. It was later shown that dipeptidyl peptidase 4 was a physiologically relevant enzyme responsible for this conversion, as well as the similar metabolism of the second incretin, glucagon-like peptide-1. Dipeptidyl peptidase-4 inhibitors are currently in use as type 2 diabetes therapeutics, and studies on islet transplantation in rodent models of type 1 diabetes have shown that dipeptidyl peptidase-4 inhibitor treatment reduces graft rejection. Additional studies on C-terminally shortened forms of GIP have shown that GIP 1-30 and a dipeptidyl peptidase-4-resistant form (D-Ala(2) GIP 1-30) are equipotent to the intact polypeptide in vitro, and administration of D-Ala(2) GIP 1-30 to diabetic rodents greatly improved glucose tolerance and reduced apoptotic cell death in islet β-cells. There are probably therefore further clinically useful effects of GIP that require investigation.
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Affiliation(s)
- Raymond A Pederson
- Diabetes Research Group Department of Cellular & Physiological Sciences University of British Columbia Vancouver British Colombia Canada
| | - Christopher Hs McIntosh
- Diabetes Research Group Department of Cellular & Physiological Sciences University of British Columbia Vancouver British Colombia Canada
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Millar PJB, Pathak V, Moffett RC, Pathak NM, Bjourson AJ, O'Kane MJ, Flatt PR, Gault VA. Beneficial metabolic actions of a stable GIP agonist following pre-treatment with a SGLT2 inhibitor in high fat fed diabetic mice. Mol Cell Endocrinol 2016; 420:37-45. [PMID: 26607806 DOI: 10.1016/j.mce.2015.11.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/10/2015] [Accepted: 11/13/2015] [Indexed: 12/18/2022]
Abstract
The purpose of the present study was to examine if a stable glucose-dependent insulinotropic polypeptide (GIP) agonist could exert beneficial metabolic control in diabetic mice which had been pre-treated with sodium-glucose-cotransporter-2 (SGLT2) inhibitor dapagliflozin (DAPA). High fat fed mice administered low dose streptozotocin (STZ) received vehicle, DAPA once-daily over 28 days, or DAPA once-daily for 14 days followed by (DAla(2))GIP once-daily for 14 days. Energy intake, body weight, glucose and insulin concentrations were measured at regular intervals. Glucose tolerance, insulin tolerance test, dual-energy X-ray absorptiometry (DEXA) and pancreatic histology were examined. Once-daily administration of (DAla(2))GIP for 14 days in high fat fed diabetic mice pre-treated with DAPA demonstrated significant decrease in body weight, blood glucose and increased insulin concentrations which were independent of changes in energy intake. Similarly, glucose tolerance, glucose-stimulated insulin secretion, insulin sensitivity and HOMA-β were significantly enhanced in (DAla(2))GIP-treated mice. DEXA analysis revealed sustained percentage body fat loss with no changes in lean mass, bone mineral content and density. Pancreatic immunohistochemical analysis revealed decreased islet number and increases in islet area, beta cell area and pancreatic insulin content. The DAPA-induced increase in alpha cell area was also reversed. Additional acute in vitro and in vivo experiments confirmed that the impaired action of (DAla(2))GIP under hyperglycaemic-induced conditions was significantly reversed by DAPA treatment. These data demonstrate that (DAla(2))GIP can exert beneficial metabolic control in high fat fed diabetic mice pre-treated with DAPA. The results highlight possibility of a targeted and personalized approach using a GIP agonist and SGLT2 inhibitor for the treatment of type 2 diabetes.
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Affiliation(s)
- P J B Millar
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, Northern Ireland, UK
| | - V Pathak
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, Northern Ireland, UK
| | - R C Moffett
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, Northern Ireland, UK
| | - N M Pathak
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, Northern Ireland, UK
| | - A J Bjourson
- Northern Ireland Centre for Stratified Medicine, University of Ulster, C-TRIC Building, Altnagelvin Hospital, Londonderry BT47 6SB, Northern Ireland, UK
| | - M J O'Kane
- Northern Ireland Centre for Stratified Medicine, University of Ulster, C-TRIC Building, Altnagelvin Hospital, Londonderry BT47 6SB, Northern Ireland, UK; Clinical Chemistry Laboratory, Western Health and Social Care Trust, Altnagelvin Hospital, Londonderry BT47 6SB, Northern Ireland, UK
| | - P R Flatt
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, Northern Ireland, UK
| | - V A Gault
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, Northern Ireland, UK.
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Tatarkiewicz K, Hargrove DM, Jodka CM, Gedulin BR, Smith PA, Hoyt JA, Lwin A, Collins L, Mamedova L, Levy OE, D'Souza L, Janssen S, Srivastava V, Ghosh SS, Parkes DG. A novel long-acting glucose-dependent insulinotropic peptide analogue: enhanced efficacy in normal and diabetic rodents. Diabetes Obes Metab 2014; 16:75-85. [PMID: 23859463 PMCID: PMC4237114 DOI: 10.1111/dom.12181] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 05/21/2013] [Accepted: 07/11/2013] [Indexed: 12/18/2022]
Abstract
AIM Glucose-dependent insulinotropic peptide (GIP) is an incretin hormone that is released from intestinal K cells in response to nutrient ingestion. We aimed to investigate the therapeutic potential of the novel N- and C-terminally modified GIP analogue AC163794. METHODS AC163794 was synthesized by solid-phase peptide synthesis. Design involved the substitution of the C-terminus tail region of the dipeptidyl peptidase IV (DPP-IV)-resistant GIP analogue [d-Ala(2) ]GIP(1-42) with the unique nine amino acid tail region of exenatide. The functional activity and binding of AC163794 to the GIP receptor were evaluated in RIN-m5F β-cells. In vitro metabolic stability was tested in human plasma and kidney membrane preparations. Acute insulinotropic effects were investigated in isolated mouse islets and during an intravenous glucose tolerance test in normal and diabetic Zucker fatty diabetic (ZDF) rats. The biological actions of AC163794 were comprehensively assessed in normal, ob/ob and high-fat-fed streptozotocin (STZ)-induced diabetic mice. Acute glucoregulatory effects of AC163794 were tested in diet-induced obese mice treated subchronically with AC3174, the exendatide analogue [Leu(14) ] exenatide. Human GIP or [d-Ala(2) ]GIP(1-42) were used for comparison. RESULTS AC163794 exhibited nanomolar functional GIP receptor potency in vitro similar to GIP and [d-Ala(2) ]GIP(1-42). AC163794 was metabolically more stable in vitro and displayed longer duration of insulinotropic action in vivo versus GIP and [d-Ala(2) ]GIP(1-42). In diabetic mice, AC163794 improved HbA1c through enhanced insulinotropic action, partial restoration of pancreatic insulin content and improved insulin sensitivity with no adverse effects on fat storage and metabolism. AC163794 provided additional baseline glucose-lowering when injected to mice treated with AC3174. CONCLUSIONS These studies support the potential use of a novel GIP analogue AC163794 for the treatment of type 2 diabetes.
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Gault VA, Bhat VK, Irwin N, Flatt PR. A novel glucagon-like peptide-1 (GLP-1)/glucagon hybrid peptide with triple-acting agonist activity at glucose-dependent insulinotropic polypeptide, GLP-1, and glucagon receptors and therapeutic potential in high fat-fed mice. J Biol Chem 2013; 288:35581-91. [PMID: 24165127 DOI: 10.1074/jbc.m113.512046] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon bind to related members of the same receptor superfamily and exert important effects on glucose homeostasis, insulin secretion, and energy regulation. The present study assessed the biological actions and therapeutic utility of novel GIP/glucagon/GLP-1 hybrid peptides. Nine novel peptides were synthesized and exhibited complete DPP-IV resistance and enhanced in vitro insulin secretion. The most promising peptide, [dA(2)]GLP-1/GcG, stimulated cAMP production in GIP, GLP-1, and glucagon receptor-transfected cells. Acute administration of [dA(2)]GLP-1/GcG in combination with glucose significantly lowered plasma glucose and increased plasma insulin in normal and obese diabetic (ob/ob) mice. Furthermore, [dA(2)]GLP-1/GcG elicited a protracted glucose-lowering and insulinotropic effect in high fat-fed mice. Twice daily administration of [dA(2)]GLP-1/GcG for 21 days decreased body weight and nonfasting plasma glucose and increased circulating plasma insulin concentrations in high fat-fed mice. Furthermore, [dA(2)]GLP-1/GcG significantly improved glucose tolerance and insulin sensitivity by day 21. Interestingly, locomotor activity was increased in [dA(2)]GLP-1/GcG mice, without appreciable changes in aspects of metabolic rate. Studies in knock-out mice confirmed the biological action of [dA(2)]GLP-1/GcG via multiple targets including GIP, GLP-1, and glucagon receptors. The data suggest significant promise for novel triple-acting hybrid peptides as therapeutic options for obesity and diabetes.
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Affiliation(s)
- Victor A Gault
- From the SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, BT52 1SA Northern Ireland, United Kingdom
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Martin CM, Irwin N, Flatt PR, Gault VA. A novel acylated form of (d-Ala2)GIP with improved antidiabetic potential, lacking effect on body fat stores. Biochim Biophys Acta Gen Subj 2013; 1830:3407-13. [DOI: 10.1016/j.bbagen.2013.03.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 03/08/2013] [Accepted: 03/08/2013] [Indexed: 10/27/2022]
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Bhat VK, Kerr BD, Vasu S, Flatt PR, Gault VA. A DPP-IV-resistant triple-acting agonist of GIP, GLP-1 and glucagon receptors with potent glucose-lowering and insulinotropic actions in high-fat-fed mice. Diabetologia 2013; 56:1417-24. [PMID: 23503814 DOI: 10.1007/s00125-013-2892-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 03/01/2013] [Indexed: 01/12/2023]
Abstract
AIMS/HYPOTHESIS We designed a chemically modified, enzyme-resistant peptide with triple-acting properties based on human glucagon with amino acid substitutions aligned to strategic positions in the sequence of glucose-dependent insulinotropic polypeptide (GIP). METHODS Y(1)-dA(2)-I(12)-N(17)-V(18)-I(27)-G(28,29)-glucagon (termed YAG-glucagon) was incubated with dipeptidylpeptidase IV (DPP-IV) to assess stability, BRIN-BD11 cells to evaluate insulin secretion, and receptor-transfected cells to examine cAMP production. Acute glucose-lowering and insulinotropic properties of YAG-glucagon were assessed in National Institutes of Health (NIH) Swiss mice, while longer-term actions on glucose homeostasis, insulin secretion, food intake and body weight were examined in high-fat-fed mice. RESULTS YAG-glucagon was resistant to DPP-IV, increased in vitro insulin secretion (1.5-3-fold; p < 0.001) and stimulated cAMP production in GIP receptor-, glucagon-like peptide-1 (GLP-1) receptor- and glucagon receptor-transfected cells. Plasma glucose levels were significantly reduced (by 51%; p < 0.01) and insulin concentrations increased (1.2-fold; p < 0.01) after acute injection of YAG-glucagon in NIH Swiss mice. Acute actions were countered by established GIP, GLP-1 and glucagon antagonists. In high-fat-fed mice, twice-daily administration of YAG-glucagon for 14 days reduced plasma glucose (40% reduction; p < 0.01) and increased plasma insulin concentrations (1.8-fold; p < 0.05). Glycaemic responses were markedly improved (19-48% reduction; p < 0.05) and insulin secretion enhanced (1.5-fold; p < 0.05) after a glucose load, which were independent of changes in insulin sensitivity, food intake and body weight. CONCLUSIONS/INTERPRETATION YAG-glucagon is a DPP-IV-resistant triple agonist of GIP, GLP-1 and glucagon receptors and exhibits beneficial biological properties suggesting that it may hold promise for treatment of type 2 diabetes.
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Affiliation(s)
- V K Bhat
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
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Bhat VK, Kerr BD, Flatt PR, Gault VA. A novel GIP-oxyntomodulin hybrid peptide acting through GIP, glucagon and GLP-1 receptors exhibits weight reducing and anti-diabetic properties. Biochem Pharmacol 2013; 85:1655-62. [DOI: 10.1016/j.bcp.2013.03.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 03/11/2013] [Accepted: 03/11/2013] [Indexed: 12/13/2022]
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Abstract
Gut hormones represent a niche subset of pharmacologically active agents that are rapidly gaining importance in medicine. Due to their exceptional specificity for their receptors, these hormones along with their analogues have attracted considerable pharmaceutical interest for the treatment of human disorders including type 2 diabetes. With the recent advances in the structural biology, a significant amount of structural information for these hormones is now available. This Minireview presents an overview of the structural aspects of these hormones, which have roles in physiological processes such as insulin secretion, as well as a discussion on the relevant structural modifications used to improve these hormones for the treatment of type 2 diabetes.
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Affiliation(s)
- Chandralal M Hewage
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
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Wallrapp C, Thoenes E, Thürmer F, Jork A, Kassem M, Geigle P. Cell-based delivery of glucagon-like peptide-1 using encapsulated mesenchymal stem cells. J Microencapsul 2012; 30:315-24. [DOI: 10.3109/02652048.2012.726281] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Cho YM, Merchant CE, Kieffer TJ. Targeting the glucagon receptor family for diabetes and obesity therapy. Pharmacol Ther 2012; 135:247-78. [DOI: 10.1016/j.pharmthera.2012.05.009] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 05/15/2012] [Indexed: 12/11/2022]
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Kim SJ, Nian C, Karunakaran S, Clee SM, Isales CM, McIntosh CHS. GIP-overexpressing mice demonstrate reduced diet-induced obesity and steatosis, and improved glucose homeostasis. PLoS One 2012; 7:e40156. [PMID: 22802954 PMCID: PMC3388996 DOI: 10.1371/journal.pone.0040156] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 06/01/2012] [Indexed: 11/19/2022] Open
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is a gastrointestinal hormone that potentiates glucose-stimulated insulin secretion during a meal. Since GIP has also been shown to exert β-cell prosurvival and adipocyte lipogenic effects in rodents, both GIP receptor agonists and antagonists have been considered as potential therapeutics in type 2 diabetes (T2DM). In the present study, we tested the hypothesis that chronically elevating GIP levels in a transgenic (Tg) mouse model would increase adipose tissue expansion and exert beneficial effects on glucose homeostasis. In contrast, although GIP Tg mice demonstrated enhanced β-cell function, resulting in improved glucose tolerance and insulin sensitivity, they exhibited reduced diet-induced obesity. Adipose tissue macrophage infiltration and hepatic steatosis were both greatly reduced, and a number of genes involved in lipid metabolism/inflammatory signaling pathways were found to be down-regulated. Reduced adiposity in GIP Tg mice was associated with decreased energy intake, involving overexpression of hypothalamic GIP. Together, these studies suggest that, in the context of over-nutrition, transgenic GIP overexpression has the potential to improve hepatic and adipocyte function as well as glucose homeostasis.
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Affiliation(s)
- Su-Jin Kim
- Department of Cellular & Physiological Sciences and the Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Cuilan Nian
- Department of Cellular & Physiological Sciences and the Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Subashini Karunakaran
- Department of Cellular & Physiological Sciences and the Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Susanne M. Clee
- Department of Cellular & Physiological Sciences and the Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Carlos M. Isales
- Departments of Orthopaedic Surgery and Cellular Biology and Anatomy, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Christopher H. S. McIntosh
- Department of Cellular & Physiological Sciences and the Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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Faivre E, Hamilton A, Hölscher C. Effects of acute and chronic administration of GIP analogues on cognition, synaptic plasticity and neurogenesis in mice. Eur J Pharmacol 2011; 674:294-306. [PMID: 22115896 DOI: 10.1016/j.ejphar.2011.11.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Revised: 10/27/2011] [Accepted: 11/04/2011] [Indexed: 12/14/2022]
Abstract
Type 2 diabetes is a risk factor for Alzheimer's disease. Insulin receptor desensitisation has been found in Alzheimer brains, which may be the underlying link. Glucose-dependent insulinotropic polypeptide (GIP), an incretin hormone, normalises insulin signalling in diabetes. GIP and the GIP receptors are widely expressed in the brain, and GIP has been shown to have growth factor and neuroprotective properties. Here we investigate the potential therapeutic properties of different doses of the protease resistant long-lasting GIP receptor agonist D-Ala2GIP and the antagonist (Pro3)GIP in C57Bl/6 mice. We found that after acute injection, D-Ala2GIP had few effects on general behaviour in the open field at any dose tested (2.5, 25, 100, or 250 nmol/kg i.p.). In memory tests, no change was observed, whilst (Pro3)GIP at 25 nmol/kg i.p. impaired memory formation. In a chronic study over 4 weeks, mice injected with D-Ala2GIP (2.5 or 25 nmol/kg i.p.) and (Pro3)GIP (25 nmol/kg i.p.) learned a water maze task and object recognition task without impairment. In LTP recording in area CA1, both (Pro3)GIP as well as D-Ala2GIP enhanced LTP formation. In addition, the proliferation of neuronal progenitor cells in the dentate gyrus was increased both by D-Ala2GIP and (Pro3)GIP. The results show that the antagonist (Pro3)GIP has agonistic effects in chronic use, and both (Pro3)GIP and the agonist D-Ala2GIP are safe to use in wt mice and induces no major behavioural side effects nor impairments in learning whilst enhancing LTP and neuronal progenitor cell proliferation, which may be useful in treating neurodegenerative diseases.
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Affiliation(s)
- Emilie Faivre
- School of Biomedical Sciences, Ulster University, Coleraine, United Kingdom
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Gault VA, Kerr BD, Harriott P, Flatt PR. Administration of an acylated GLP-1 and GIP preparation provides added beneficial glucose-lowering and insulinotropic actions over single incretins in mice with Type 2 diabetes and obesity. Clin Sci (Lond). 2011;121:107-117. [PMID: 21332446 DOI: 10.1042/cs20110006] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The present study examined the glucose-lowering and insulinotropic properties of acylated GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide) peptides in Type 2 diabetes and obesity. GLP-1, GIP, Liraglutide, N-AcGIP(Lys(37)Myr) (N-acetylGIP with myristic acid conjugated at Lys(37)), a simple combination of both peptides and a Lira-AcGIP preparation [overnight preparation of Liraglutide and N-AcGIP(Lys(37)Myr)] were incubated with DPP-IV (dipeptidyl peptidase-IV) to assess peptide stability, and BRIN-BD11 cells were used to evaluate cAMP production and insulin secretion. Acute glucose-lowering and insulinotropic actions were evaluated in Swiss TO mice. Subchronic studies on glucose homoeostasis, insulin secretion, food intake and bodyweight were evaluated in ob/ob mice. Liraglutide, N-AcGIP(Lys(37)Myr), a simple combination of both peptides and the Lira-AcGIP preparation demonstrated improved DPP-IV resistance (P<0.001), while stimulating cAMP production and insulin secretion (1.4-2-fold; P<0.001). The Lira-AcGIP preparation was more potent at lowering plasma glucose (20-51% reduction; P<0.05-P<0.001) and stimulating insulin secretion (1.5-1.8-fold; P<0.05-P<0.001) compared with Liraglutide and N-AcGIP(Lys(37)Myr) or a simple peptide combination. Daily administration of the Lira-AcGIP preparation to ob/ob mice lowered bodyweight (7-9%; P<0.05), food intake (23%; P<0.05) and plasma glucose (46% reduction; P<0.001), while increasing plasma insulin (1.5-1.6-fold; P<0.001). The Lira-AcGIP preparation enhanced glucose tolerance, insulin response to glucose and insulin content (P<0.05-P<0.001). These findings demonstrate that a combined preparation of the acylated GLP-1 and GIP peptides Liraglutide and N-AcGIP(Lys(37)Myr) markedly improved glucose-lowering and insulinotropic properties in diabetic obesity compared with either incretin mimetic given individually.
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Irwin N, Francis JME, Flatt PR. Insulin modulates glucose-dependent insulinotropic polypeptide (GIP) secretion from enteroendocrine K cells in rats. Biol Chem 2011; 392:909-18. [PMID: 21851286 DOI: 10.1515/bc.2011.176] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Effects of insulin excess and deficiency on glucose-dependent insulinotropic polypeptide (GIP) was examined in rats following insulinoma transplantation or streptozotocin (STZ) administration. Over 14 days, food intake was increased (p < 0.001) in both groups of rats, with decreased body weight (p < 0.01) in STZ rats. Non-fasting plasma glucose levels were decreased (p < 0.01) and plasma insulin levels increased (p < 0.001) in insulinoma-bearing rats, whereas STZ treatment elevated glucose (p < 0.001) and decreased insulin (p < 0.01). Circulating GIP concentrations were elevated (p < 0.01) in both animal models. At 14 days, oral glucose resulted in a decreased glycaemic excursion (p < 0.05) with concomitant elevations in insulin release (p < 0.001) in insulinoma-bearing rats, whereas STZ-treated rats displayed similar glucose-lowering effects but reduced insulin levels (p < 0.01). GIP concentrations were augmented in STZ rats (p < 0.05) following oral glucose. Plasma glucose and insulin concentrations were not affected by oral fat, but fat-induced GIP secretion was particularly (p < 0.05) increased in insulinoma-bearing rats. Exogenous GIP enhanced (p < 0.05) glucose-lowering in all groups of rats accompanied by insulin releasing (p < 0.001) effects in insulinoma-bearing and control rats. Both rat models exhibited increased (p < 0.001) intestinal weight but decreased intestinal GIP concentrations. These data suggest that circulating insulin has direct and indirect effects on the synthesis and secretion of GIP.
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Affiliation(s)
- Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, BT52 1SA, UK.
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Abstract
The intestine is an important metabolic organ that has gained attention in recent years for the newly identified role that it plays in the pathophysiology of various metabolic diseases including obesity, insulin resistance and diabetes. Recent insights regarding the role of enteroendocrine hormones, such as GIP, GLP-1, and PYY in metabolic diseases, as well as the emerging role of the gut microbial community and gastric bypass bariatric surgeries in modulating metabolic function and dysfunction have sparked a wave of interest in understanding the mechanisms involved, in an effort to identify new therapeutics and novel regulators of metabolism. This review summarizes the current evidence that the gastrointestinal tract has a key role in the development of obesity, inflammation, insulin resistance and diabetes and discusses the possible players that can be targeted for therapeutic intervention.
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Affiliation(s)
- William D Bradley
- Metabolic and Vascular Diseases Department, Hoffmann La-Roche Inc., Nutley, NJ, USA
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Szalowska E, Meijer K, Kloosterhuis N, Razaee F, Priebe M, Vonk RJ. Sub-chronic administration of stable GIP analog in mice decreases serum LPL activity and body weight. Peptides 2011; 32:938-45. [PMID: 21334410 DOI: 10.1016/j.peptides.2011.02.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 02/10/2011] [Accepted: 02/12/2011] [Indexed: 01/19/2023]
Abstract
GIP receptor knockout mice were shown to be protected from the development of obesity on a high fat diet, suggesting a role of GIP in the development of obesity. In our study we aimed to test the hypothesis if excess of GIP could accelerate development of obesity and to identify GIP gene targets in adipose tissue. Therefore, mice were kept on a chow or a high fat diet and during the last 2 weeks D-Ala(2)-GIP or PBS injections were performed. Afterwards, serum LPL activity and several biochemical parameters (TG, FFA, cholesterol, glucose, insulin, resistin, IL-6, IL-1β, TNFα, GIP) were measured. Fat tissue was isolated and QPCR was performed for a set of genes involved in energy metabolism and inflammation. A DNA-microarray was used to identify GIP gene targets in adipose tissue of the chow diet group. We found that the D-Ala(2)-GIP injections caused a significant decrease in both body weight and LPL activity compared to controls. Serum biochemical parameters were not affected by D-Ala(2)-GIP, with an exception for resistin and insulin. The set of inflammatory genes were significantly decreased in adipose tissue in the D-Ala(2)-GIP injected animals on a chow diet. A DNA-microarray revealed that APO-genes and CYP-genes were affected by D-Ala(2)-GIP treatment in adipose tissue. These results suggest that the body weight-reducing effect of D-Ala(2)-GIP may be explained by lower LPL activity and insulin serum level. Moreover, the identified GIP candidate gene targets in adipose tissue link GIP action to lipid metabolism exerted by APO and CYP genes.
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Affiliation(s)
- Ewa Szalowska
- Centre for Medical Biomics, UMCG, University of Groningen, The Netherlands.
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