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Lafferty RA, Flatt PR, Irwin N. NPYR modulation: Potential for the next major advance in obesity and type 2 diabetes management? Peptides 2024:171256. [PMID: 38825012 DOI: 10.1016/j.peptides.2024.171256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 05/13/2024] [Accepted: 05/30/2024] [Indexed: 06/04/2024]
Abstract
The approval of the glucagon-like peptide 1 (GLP-1) mimetics semaglutide and liraglutide for management of obesity, independent of type 2 diabetes (T2DM), has initiated a resurgence of interest in gut-hormone derived peptide therapies for the management of metabolic diseases, but side-effect profile is a concern for these medicines. However, the recent approval of tirzepatide for obesity and T2DM, a glucose-dependent insulinotropic polypeptide (GIP), GLP-1 receptor co-agonist peptide therapy, may provide a somewhat more tolerable option. Despite this, an increasing number of non-incretin alternative peptides are in development for obesity, and it stands to reason that other hormones will take to the limelight in the coming years, such as peptides from the neuropeptide Y family. This narrative review outlines the therapeutic promise of the neuropeptide Y family of peptides, comprising of the 36 amino acid polypeptides neuropeptide Y (NPY), peptide tyrosine-tyrosine (PYY) and pancreatic polypeptide (PP), as well as their derivatives. This family of peptides exerts a number of metabolically relevant effects such as appetite regulation and can influence pancreatic beta-cell survival. Although some of these actions still require full translation to the human setting, potential therapeutic application in obesity and type 2 diabetes is conceivable. However, like GLP-1 and GIP, the endogenous NPY, PYY and PP peptide forms are subject to rapid in vivo degradation and inactivation by the serine peptidase, dipeptidyl-peptidase 4 (DPP-4), and hence require structural modification to prolong circulating half-life. Numerous protective modification strategies are discussed in this regard herein, alongside related impact on biological activity profile and therapeutic promise.
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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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2
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Bailey CJ, Flatt PR. Duodenal enteroendocrine cells and GIP as treatment targets for obesity and type 2 diabetes. Peptides 2024; 174:171168. [PMID: 38320643 DOI: 10.1016/j.peptides.2024.171168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 02/02/2024] [Accepted: 02/02/2024] [Indexed: 02/08/2024]
Abstract
The duodenum is an important source of endocrine and paracrine signals controlling digestion and nutrient disposition, notably including the main incretin hormone glucose-dependent insulinotropic polypeptide (GIP). Bariatric procedures that prevent nutrients from contact with the duodenal mucosa are particularly effective interventions to reduce body weight and improve glycaemic control in obesity and type 2 diabetes. These procedures take advantage of increased nutrient delivery to more distal regions of the intestine which enhances secretion of the other incretin hormone glucagon-like peptide-1 (GLP-1). Preclinical experiments have shown that either an increase or a decrease in the secretion or action of GIP can decrease body weight and blood glucose in obesity and non-insulin dependent hyperglycaemia, but clinical studies involving administration of GIP have been inconclusive. However, a synthetic dual agonist peptide (tirzepatide) that exerts agonism at receptors for GIP and GLP-1 has produced marked weight-lowering and glucose-lowering effects in people with obesity and type 2 diabetes. This appears to result from chronic biased agonism in which the novel conformation of the peptide triggers enhanced signalling by the GLP-1 receptor through reduced internalisation while reducing signalling by the GIP receptor directly or via functional antagonism through increased internalisation and degradation.
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Affiliation(s)
| | - Peter R Flatt
- Diabetes Research Centre, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine BT52 1SA Northern Ireland, UK
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Sridhar A, Khan D, Flatt PR, Moffett CR, Irwin N. GLP-1 receptor agonism and GIP receptor antagonism induce substantial alterations in enteroendocrine and islet cell populations in obese high fat fed mice. Peptides 2023; 169:171093. [PMID: 37660881 DOI: 10.1016/j.peptides.2023.171093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/21/2023] [Accepted: 08/30/2023] [Indexed: 09/05/2023]
Abstract
Effects of sustained activation of glucagon-like peptide-1 (GLP-1) receptors (GLP-1R) as well as antagonism of receptors for glucose-dependent insulinotropic peptide (GIP) on intestinal morphology and related gut hormone populations have not been fully investigated. The present study assesses the impact of 21-days twice daily treatment with the GLP-1R agonist exendin-4 (Ex-4), or the GIP receptor (GIPR) antagonist mGIP(3-30), on these features in obese mice fed a high fat diet (HFD). HFD mice presented with reduced crypt depth when compared to normal diet (ND) controls, which was reversed by Ex-4 treatment. Both regimens lead to an enlargement of villi length in HFD mice. HFD mice had increased numbers of GIP and PYY positive ileal cells, with both treatment interventions reversing the effect on PYY positive cells, but only Ex-4 restoring GIP ileal cell populations to ND levels. Ex-4 and mGIP (3-30) marginally decreased GLP-1 villi immunoreactivity and countered the reduction of ileal GLP-1 content caused by HFD. As expected, HFD mice presented with elevated pancreatic islet area. Interestingly, mGIP(3-30), but not Ex-4, enhanced islet and beta-cell areas in HFD mice despite lack of effect of beta-cell turnover, whilst Ex-4 increased delta-cell area. Co-localisation of islet PYY or GLP-1 with glucagon was increased by Ex-4, whilst islet PYY co-immunoreactivity with somatostatin was enhanced by mGIP(3-30) treatment. These observations highlight potential new mechanisms linked to the metabolic benefits of GLP-1R agonism and GIPR antagonism in obesity.
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Affiliation(s)
- Ananyaa Sridhar
- Diabetes Research Centre, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, UK
| | - Dawood Khan
- Diabetes Research Centre, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- Diabetes Research Centre, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, UK
| | - Charlotte R Moffett
- Diabetes Research Centre, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- Diabetes Research Centre, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, UK.
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El K, Douros JD, Willard FS, Novikoff A, Sargsyan A, Perez-Tilve D, Wainscott DB, Yang B, Chen A, Wothe D, Coupland C, Tschöp MH, Finan B, D'Alessio DA, Sloop KW, Müller TD, Campbell JE. The incretin co-agonist tirzepatide requires GIPR for hormone secretion from human islets. Nat Metab 2023; 5:945-954. [PMID: 37277609 PMCID: PMC10290954 DOI: 10.1038/s42255-023-00811-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 04/21/2023] [Indexed: 06/07/2023]
Abstract
The incretins glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) mediate insulin responses that are proportionate to nutrient intake to facilitate glucose tolerance1. The GLP-1 receptor (GLP-1R) is an established drug target for the treatment of diabetes and obesity2, whereas the therapeutic potential of the GIP receptor (GIPR) is a subject of debate. Tirzepatide is an agonist at both the GIPR and GLP-1R and is a highly effective treatment for type 2 diabetes and obesity3,4. However, although tirzepatide activates GIPR in cell lines and mouse models, it is not clear whether or how dual agonism contributes to its therapeutic benefit. Islet beta cells express both the GLP-1R and the GIPR, and insulin secretion is an established mechanism by which incretin agonists improve glycemic control5. Here, we show that in mouse islets, tirzepatide stimulates insulin secretion predominantly through the GLP-1R, owing to reduced potency at the mouse GIPR. However, in human islets, antagonizing GIPR activity consistently decreases the insulin response to tirzepatide. Moreover, tirzepatide enhances glucagon secretion and somatostatin secretion in human islets. These data demonstrate that tirzepatide stimulates islet hormone secretion from human islets through both incretin receptors.
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Affiliation(s)
- Kimberley El
- Duke Molecular Physiology Institute, Durham, NC, USA
| | | | - Francis S Willard
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Aaron Novikoff
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | | | - Diego Perez-Tilve
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - David B Wainscott
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Bin Yang
- Novo Nordisk Research Center, Indianapolis, IN, USA
| | - Alex Chen
- Duke Molecular Physiology Institute, Durham, NC, USA
| | - Donald Wothe
- Duke Molecular Physiology Institute, Durham, NC, USA
| | - Callum Coupland
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Mattias H Tschöp
- Helmholtz Zentum München, Neuherberg, Germany
- Technische Universität München, München, Germany
| | - Brian Finan
- Novo Nordisk Research Center, Indianapolis, IN, USA
| | - David A D'Alessio
- Duke Molecular Physiology Institute, Durham, NC, USA
- Division of Endocrinology, Department of Medicine, Duke University, Durham, NC, USA
| | - Kyle W Sloop
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA.
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, Neuherberg, Germany.
- German Center for Diabetes Research (DZD), Neuherberg, Germany.
| | - Jonathan E Campbell
- Duke Molecular Physiology Institute, Durham, NC, USA.
- Division of Endocrinology, Department of Medicine, Duke University, Durham, NC, USA.
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC, USA.
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Lafferty RA, Flatt PR, Irwin N. GLP-1/GIP analogues: potential impact in the landscape of obesity pharmacotherapy. Expert Opin Pharmacother 2023; 24:587-597. [PMID: 36927378 DOI: 10.1080/14656566.2023.2192865] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
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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Tanday N, Lafferty RA, Flatt PR, Irwin N. Beneficial metabolic effects of recurrent periods of beta-cell rest and stimulation using stable neuropeptide Y1 and glucagon-like peptide-1 receptor agonists. Diabetes Obes Metab 2022; 24:2353-2363. [PMID: 35848461 PMCID: PMC9804730 DOI: 10.1111/dom.14821] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 07/01/2022] [Accepted: 07/12/2022] [Indexed: 01/09/2023]
Abstract
AIM To examine whether sequential administration of (d-Arg35 )-sea lamprey peptide tyrosine tyrosine (1-36) (SL-PYY) and the glucagon-like peptide-1 (GLP-1) mimetic, liraglutide, has beneficial effects in diabetes. METHODS SL-PYY is an enzymatically stable neuropeptide Y1 receptor (NPY1R) agonist known to induce pancreatic beta-cell rest and improve overall beta-cell health. We employed SL-PYY and liraglutide to induce appropriate recurrent periods of beta-cell rest and stimulation, to assess therapeutic benefits in high fat fed (HFF) mice with streptozotocin (STZ)-induced insulin deficiency, namely HFF-STZ mice. RESULTS Previous studies confirm that, at a dose of 0.25 nmol/kg, liraglutide exerts bioactivity over an 8-12 hour period in mice. Initial pharmacokinetic analysis revealed that 75 nmol/kg SL-PYY yielded a similar plasma drug time profile. When SL-PYY (75 nmol/kg) and liraglutide (0.25 nmol/kg) were administered sequentially at 08:00 AM and 08:00 PM, respectively, to HFF-STZ mice for 28 days, reductions in energy intake, body weight, circulating glucose, insulin and glucagon were noted. Similarly positive, but slightly less striking, effects were also apparent with twice-daily liraglutide-only therapy. The sequential SL-PYY and liraglutide treatment also improved insulin sensitivity and glucose-induced insulin secretory responses, which was not apparent with liraglutide treatment, although benefits on glucose tolerance were mild. Interestingly, combined therapy also elevated pancreatic insulin, decreased pancreatic glucagon and enhanced the plasma insulin/glucagon ratio compared with liraglutide alone. This was not associated with an enhancement of beneficial changes in islet cell areas, proliferation or apoptosis compared with liraglutide alone, but the numbers of centrally stained glucagon-positive islet cells were reduced by sequential combination therapy. CONCLUSION These data show that NPY1R-induced intervals of beta-cell rest, combined with GLP-1R-stimulated periods of beta-cell stimulation, should be further evaluated as an effective treatment option for obesity-driven forms of diabetes.
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Affiliation(s)
- Neil Tanday
- Biomedical Sciences Research InstituteCentre for Diabetes, Ulster UniversityColeraineNorthern Ireland
| | - Ryan A. Lafferty
- Biomedical Sciences Research InstituteCentre for Diabetes, Ulster UniversityColeraineNorthern Ireland
| | - Peter R. Flatt
- Biomedical Sciences Research InstituteCentre for Diabetes, Ulster UniversityColeraineNorthern Ireland
| | - Nigel Irwin
- Biomedical Sciences Research InstituteCentre for Diabetes, Ulster UniversityColeraineNorthern Ireland
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7
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Discovery of a potent GIPR peptide antagonist that is effective in rodent and human systems. Mol Metab 2022; 66:101638. [PMID: 36400403 PMCID: PMC9719863 DOI: 10.1016/j.molmet.2022.101638] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/08/2022] [Accepted: 11/08/2022] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE Glucose-dependent insulinotropic polypeptide (GIP) is one of the two major incretin factors that regulate metabolic homeostasis. Genetic ablation of its receptor (GIPR) in mice confers protection against diet-induced obesity (DIO), while GIPR neutralizing antibodies produce additive weight reduction when combined with GLP-1R agonists in preclinical models and clinical trials. Conversely, GIPR agonists have been shown to promote weight loss in rodents, while dual GLP-1R/GIPR agonists have proven superior to GLP-1R monoagonists for weight reduction in clinical trials. We sought to develop a long-acting, specific GIPR peptide antagonist as a tool compound suitable for investigating GIPR pharmacology in both rodent and human systems. METHODS We report a structure-activity relationship of GIPR peptide antagonists based on the human and mouse GIP sequences with fatty acid-based protraction. We assessed these compounds in vitro, in vivo in DIO mice, and ex vivo in islets from human donors. RESULTS We report the discovery of a GIP(5-31) palmitoylated analogue, [Nα-Ac, L14, R18, E21] hGIP(5-31)-K11 (γE-C16), which potently inhibits in vitro GIP-mediated cAMP generation at both the hGIPR and mGIPR. In vivo, this peptide effectively blocks GIP-mediated reductions in glycemia in response to exogenous and endogenous GIP and displays a circulating pharmacokinetic profile amenable for once-daily dosing in rodents. Co-administration with the GLP-1R agonist semaglutide and this GIPR peptide antagonist potentiates weight loss compared to semaglutide alone. Finally, this antagonist inhibits GIP- but not GLP-1-stimulated insulin secretion in intact human islets. CONCLUSIONS Our work demonstrates the discovery of a potent, specific, and long-acting GIPR peptide antagonist that effectively blocks GIP action in vitro, ex vivo in human islets, and in vivo in mice while producing additive weight-loss when combined with a GLP-1R agonist in DIO mice.
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Atanasova-Panchevska N, Stojchevski R, Hadzi-Petrushev N, Mitrokhin V, Avtanski D, Mladenov M. Antibacterial and Antiviral Properties of Tetrahydrocurcumin-Based Formulations: An Overview of Their Metabolism in Different Microbiotic Compartments. Life (Basel) 2022; 12:1708. [PMID: 36362863 PMCID: PMC9696410 DOI: 10.3390/life12111708] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/13/2022] [Accepted: 10/23/2022] [Indexed: 08/29/2023] Open
Abstract
In this review, the basic metabolic characteristics of the curcuminoid tetrahydrocurcumin (THC) at the level of the intestinal microbiota were addressed. Special attention was given to the bactericidal effects of one of the THC-phospholipid formulations, which has shown greater bioavailability and activity than pure THC. Similarly, quinoline derivatives and amino acid conjugates of THC have also shown antibacterial effects in the gut. The microbial effect of pure THC is particularly pronounced in pathophysiological conditions related to the function of the intestinal microbiota, such as type II diabetes. Furthermore, the antiviral characteristics of Cur compared to those of THC are more pronounced in preventing the influenza virus. In the case of HIV infections, the new microemulsion gel formulations of THC possess high retention during preventive application in the vagina and, at the same time, do not disturb the vaginal microbiota, which is critical in maintaining low vaginal pH. Based on the reviewed literature, finding new formulations of THC which can increase its bioavailability and activity and emphasize its antibacterial and antiviral characteristics could be very important. Applying such THC formulations in preventing and treating ailments related to the microbiotic compartments in the body would be beneficial from a medical point of view.
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Affiliation(s)
- Natalija Atanasova-Panchevska
- Faculty of Natural Sciences and Mathematics, Institute of Biology, Ss. Cyril and Methodius University, P.O. Box 162, 1000 Skopje, North Macedonia
| | - Radoslav Stojchevski
- Faculty of Natural Sciences and Mathematics, Institute of Biology, Ss. Cyril and Methodius University, P.O. Box 162, 1000 Skopje, North Macedonia
- Friedman Diabetes Institute, Lenox Hill Hospital, Northwell Health, 110 E 59th Street, New York, NY 10022, USA
| | - Nikola Hadzi-Petrushev
- Faculty of Natural Sciences and Mathematics, Institute of Biology, Ss. Cyril and Methodius University, P.O. Box 162, 1000 Skopje, North Macedonia
| | - Vadim Mitrokhin
- Department of Physiology, Pirogov Russian National Research Medical University, Ostrovityanova Street, 1, 117997 Moscow, Russia
| | - Dimiter Avtanski
- Friedman Diabetes Institute, Lenox Hill Hospital, Northwell Health, 110 E 59th Street, New York, NY 10022, USA
| | - Mitko Mladenov
- Faculty of Natural Sciences and Mathematics, Institute of Biology, Ss. Cyril and Methodius University, P.O. Box 162, 1000 Skopje, North Macedonia
- Department of Physiology, Pirogov Russian National Research Medical University, Ostrovityanova Street, 1, 117997 Moscow, Russia
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9
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Kalwat MA, Scheuner D, Rodrigues-dos-Santos K, Eizirik DL, Cobb MH. The Pancreatic ß-cell Response to Secretory Demands and Adaption to Stress. Endocrinology 2021; 162:bqab173. [PMID: 34407177 PMCID: PMC8459449 DOI: 10.1210/endocr/bqab173] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Indexed: 02/06/2023]
Abstract
Pancreatic β cells dedicate much of their protein translation capacity to producing insulin to maintain glucose homeostasis. In response to increased secretory demand, β cells can compensate by increasing insulin production capability even in the face of protracted peripheral insulin resistance. The ability to amplify insulin secretion in response to hyperglycemia is a critical facet of β-cell function, and the exact mechanisms by which this occurs have been studied for decades. To adapt to the constant and fast-changing demands for insulin production, β cells use the unfolded protein response of the endoplasmic reticulum. Failure of these compensatory mechanisms contributes to both type 1 and 2 diabetes. Additionally, studies in which β cells are "rested" by reducing endogenous insulin demand have shown promise as a therapeutic strategy that could be applied more broadly. Here, we review recent findings in β cells pertaining to the metabolic amplifying pathway, the unfolded protein response, and potential advances in therapeutics based on β-cell rest.
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Affiliation(s)
- Michael A Kalwat
- Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA
| | - Donalyn Scheuner
- Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA
| | | | - Decio L Eizirik
- Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles, Brussels, Belgium
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
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10
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Tanday N, Moffett RC, Gault VA, Flatt PR, Irwin N. Enzymatically stable analogue of the gut-derived peptide xenin on beta-cell transdifferentiation in high fat fed and insulin-deficient Ins1 Cre/+ ;Rosa26-eYFP mice. Diabetes Metab Res Rev 2021; 37:e3384. [PMID: 32662136 DOI: 10.1002/dmrr.3384] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/25/2020] [Accepted: 07/06/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND The antidiabetic effects of the gut hormone xenin include augmenting insulin secretion and positively affecting pancreatic islet architecture. METHODS The current study has further probed pancreatic effects through sub-chronic administration of the long-acting xenin analogue, xenin-25[Lys13 PAL], in both high fat fed (HFF) and streptozotocin (STZ)-induced insulin-deficient Ins1Cre/+ ;Rosa26-eYFP transgenic mice. Parallel effects on metabolic control and pancreatic islet morphology, including islet beta-cell lineage tracing were also assessed. RESULTS Xenin-25[Lys13 PAL] treatment reversed body weight loss induced by STZ, increased plasma insulin and decreased blood glucose levels. There were less obvious effects on these parameters in HFF mice, but all xenin-25[Lys13 PAL] treated mice exhibited decreased pancreatic alpha-cell areas and circulating glucagon. Xenin-25[Lys13 PAL] treatment fully, or partially, returned overall islet and beta-cell areas in STZ- and HFF mice to those of lean control animals, respectively, and was consistently associated with decreased beta-cell apoptosis. Interestingly, xenin-25[Lys13 PAL] also increased beta-cell proliferation and decreased alpha-cell apoptosis in STZ mice, with reduced alpha-cell growth noted in HFF mice. Lineage tracing studies revealed that xenin-25[Lys13 PAL] reduced the number of insulin positive pancreatic islet cells that lost their beta-cell identity, in keeping with a decreased transition of insulin positive to glucagon positive cells. These beneficial effects on islet cell differentiation were linked to maintained expression of Pdx1 within beta-cells. Xenin-25[Lys13 PAL] treatment was also associated with increased numbers of smaller sized islets in both models. CONCLUSIONS Benefits of xenin-25[Lys13 PAL] on diabetes includes positive modulation of islet cell differentiation, in addition to promoting beta-cell growth and survival.
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Affiliation(s)
- Neil Tanday
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - R Charlotte Moffett
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Victor A Gault
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
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11
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Yuan T, Yin Z, Yan Z, Hao Q, Zeng J, Li L, Zhao J. Tetrahydrocurcumin ameliorates diabetes profiles of db/db mice by altering the composition of gut microbiota and up-regulating the expression of GLP-1 in the pancreas. Fitoterapia 2020; 146:104665. [DOI: 10.1016/j.fitote.2020.104665] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 06/06/2020] [Accepted: 06/07/2020] [Indexed: 01/09/2023]
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12
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Graham GV, Conlon JM, Abdel-Wahab YH, Flatt PR. Glucagon from the phylogenetically ancient paddlefish provides a template for the design of a long-acting peptide with effective anti-diabetic and anti-obesity activities. Eur J Pharmacol 2020; 878:173101. [PMID: 32320703 DOI: 10.1016/j.ejphar.2020.173101] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/26/2020] [Accepted: 04/06/2020] [Indexed: 12/13/2022]
Abstract
This study has examined the in vitro and in vivo anti-diabetic properties of the peptidase-resistant analogues [D-Ser2]palmitoyl-paddlefish glucagon and [D-Ser2]palmitoyl-lamprey glucagon. The peptides stimulated insulin release from BRIN-BD11 clonal β-cells and isolated mouse pancreatic islets and also enhanced cAMP production in cells transfected with the human GLP-1 receptor and with the human glucagon receptor. The insulinotropic actions of the peptides were attenuated in INS-1 cells lacking GLP-1 and glucagon receptors. [D-Ser2]palmitoyl-paddlefish glucagon stimulated proliferation of BRIN-BD11 cells and protected against cytokine-mediated apoptosis as effectively as GLP-1. The analogue was more effective than the native peptide or the lamprey glucagon analogue in acutely lowering blood glucose and elevating plasma insulin in lean mice even when administered up to 4 h before a glucose load. Twice daily administration of [D-Ser2]palmitoyl-paddlefish glucagon to high-fat fed mice over 21 days reduced food intake, body weight, non-fasting blood glucose and plasma insulin concentrations, as well as significantly improving glucose tolerance and insulin resistance and decreasing α-cell area and pancreatic insulin content. Islet expression of the Gcgr, Glp1r, Gipr and Slc2a2 (GLUT-2) genes significantly increased. These data demonstrate that long-acting peptide [D-Ser2]palmitoyl-paddlefish glucagon exerts beneficial metabolic properties in diabetic mice via Ggcr- and Glp1r-activated pathways and so shows potential as a template for further development into an agent for treatment of patients with obesity-related Type 2 diabetes.
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Affiliation(s)
- Galyna V Graham
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
| | - J Michael Conlon
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK.
| | - Yasser H Abdel-Wahab
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
| | - Peter R Flatt
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
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Lafferty RA, Tanday N, McCloskey A, Bompada P, De Marinis Y, Flatt PR, Irwin N. Peptide YY (1-36) peptides from phylogenetically ancient fish targeting mammalian neuropeptide Y1 receptors demonstrate potent effects on pancreatic β-cell function, growth and survival. Diabetes Obes Metab 2020; 22:404-416. [PMID: 31692207 DOI: 10.1111/dom.13908] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 10/31/2019] [Accepted: 10/31/2019] [Indexed: 02/06/2023]
Abstract
AIM To investigate the antidiabetic efficacy of enzymatically stable Peptide YY (PYY) peptides from phylogenetically ancient fish. MATERIALS AND METHODS N-terminally stabilized, PYY (1-36) sequences from Amia calva (bowfin), Oncorhynchus mykiss (trout), Petromyzon marinus (sea lamprey) and Scaphirhynchus albus (sturgeon), were synthesized, and both biological actions and antidiabetic therapeutic efficacy were assessed. RESULTS All fish PYY (1-36) peptides were resistant to dipeptidyl peptidase-4 (DPP-4) degradation and inhibited glucose- and alanine-induced (P < 0.05 to P < 0.001) insulin secretion. In addition, PYY (1-36) peptides imparted significant (P < 0.05 to P < 0.001) β-cell proliferative and anti-apoptotic benefits. Proliferative effects were almost entirely absent in β cells with CRISPR-Cas9-induced knockout of Npyr1. In contrast to human PYY (1-36), the piscine-derived peptides lacked appetite-suppressive actions. Twice-daily administration of sea lamprey PYY (1-36), the superior bioactive peptide, for 21 days significantly (P < 0.05 to P < 0.001) decreased fluid intake, non-fasting glucose and glucagon in streptozotocin (STZ)-induced diabetic mice. In addition, glucose tolerance, insulin sensitivity, pancreatic insulin and glucagon content were significantly improved. Metabolic benefits were linked to positive changes in pancreatic islet morphology as a result of augmented (P < 0.001) proliferation and decreased apoptosis of β cells. Sturgeon PYY (1-36) exerted similar but less impressive effects in STZ mice. CONCLUSION These observations reveal, for the first time, that PYY (1-36) peptide sequences from phylogenetically ancient fish replicate the pancreatic β-cell benefits of human PYY (1-36) and have clear potential for the treatment of type 2 diabetes.
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Affiliation(s)
- Ryan A Lafferty
- SAAD Centre for Pharmacy and Diabetes, Biomedical Sciences Research Institute, University of Ulster, Coleraine, UK
| | - Neil Tanday
- SAAD Centre for Pharmacy and Diabetes, Biomedical Sciences Research Institute, University of Ulster, Coleraine, UK
| | - Andrew McCloskey
- SAAD Centre for Pharmacy and Diabetes, Biomedical Sciences Research Institute, University of Ulster, Coleraine, UK
| | - Pradeep Bompada
- Genomics, Diabetes and Endocrinology, Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - Yang De Marinis
- Genomics, Diabetes and Endocrinology, Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, Biomedical Sciences Research Institute, University of Ulster, Coleraine, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, Biomedical Sciences Research Institute, University of Ulster, Coleraine, UK
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Development and characterisation of a peptidergic N-and C-terminally stabilised mammalian NPY1R agonist which protects against diabetes induction. Biochim Biophys Acta Gen Subj 2020; 1864:129543. [PMID: 32007578 DOI: 10.1016/j.bbagen.2020.129543] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/27/2020] [Accepted: 01/28/2020] [Indexed: 02/08/2023]
Abstract
BACKGROUND PYY (1-36) peptides from phylogenetically ancient fish, such as sea lamprey, have previously been shown to function as specific neuropeptide Y1 receptor (NPYR1) agonists. Although, sea lamprey PYY (1-36) is N-terminally stable, we reveal in this study that the peptide is subject to endopeptidase mediated C-terminal dipeptide degradation. In an attempt to prevent this, (d-Arg35)-sea lamprey PYY (1-36) was developed. METHODS In vitro bioassays assessed enzymatic stability, insulinostatic activity as well as beta-cell anti-apoptotic actions of (d-Arg35)-sea lamprey PYY (1-36). Follow-up studies examined the impact of twice daily administration of sea lamprey PYY (1-36) or (d-Arg35)-sea lamprey PYY (1-36) in multiple low dose STZ-induced diabetic mice. RESULTS (d-Arg35)-sea lamprey PYY (1-36) was fully resistant to plasma enzymatic degradation. The peptide possessed similar significant insulinostatic, as well as positive anti-apoptotic biological actions, as the parent peptide. Sea lamprey PYY (1-36) and (d-Arg35)-sea lamprey PYY (1-36) delayed diabetes progression in STZ mice. Both treatment interventions induced a significant decrease in body weight, food and fluid intake as well as glucose and glucagon concentrations. In addition, glucose tolerance, plasma and pancreatic insulin were partially normalised. (d-Arg35)-sea lamprey PYY (1-36) was significantly more effective than sea lamprey PYY (1-36) in terms of enhancing glucose-stimulate insulin release. Both treatments improved pancreatic islet morphology, linked to decreased apoptosis of beta-cells. CONCLUSION We present (d-Arg35)-sea lamprey PYY (1-36) as the first-in-class N- and C-terminally stable PYY (1-36) peptide analogue. GENERAL SIGNIFICANCE Enzymatically stable, long-acting PYY (1-36) peptides highlight the therapeutic benefits of sustained activation of NPYR1's in diabetes.
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Graham GV, McCloskey A, Abdel-Wahab YH, Conlon JM, Flatt PR. A long-acting, dual-agonist analogue of lamprey GLP-1 shows potent insulinotropic, β-cell protective, and anorexic activities and improves glucose homeostasis in high fat-fed mice. Mol Cell Endocrinol 2020; 499:110584. [PMID: 31539596 DOI: 10.1016/j.mce.2019.110584] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/05/2019] [Accepted: 09/16/2019] [Indexed: 12/12/2022]
Abstract
Peptidase-resistant analogues of GLP-1 peptides from sea lamprey and paddlefish ([D-Ala2]palmitoyl-lamprey GLP-1 and [D-Ala2]palmitoyl-paddlefish GLP-1) produced significant (P ≤ 0.05) and concentration-dependent increases in insulin release from BRIN-BD11 clonal β-cells and from isolated mouse islets. Both analogues retained the ability of the native peptides to activate both the GLP-1 receptor (GLP1R) and the glucagon receptor (GCGR). [D-Ala2]palmitoyl-lamprey GLP-1 significantly (P < 0.001) stimulated proliferation of BRIN-BD11 cells and protected against cytokine-induced apoptosis. Administration of the lamprey analogue (25 nmol/kg body weight) to lean mice up to 4 h before a glucose load improved glucose tolerance and increased plasma insulin concentrations. Twice daily administration of the lamprey GLP-1 analogue to high fat-fed mice for 21 days decreased body weight, food intake, and circulating glucose and insulin concentrations. The analogue significantly improved glucose tolerance and insulin sensitivity with beneficial effects on islet β-cell area and insulin secretory responsiveness. Islet gene expression of Glp1r, Gcgr and Gipr significantly increased. The lamprey GLP-1 analogue shows therapeutic promise for treatment of patients with obesity-related Type 2 diabetes.
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Affiliation(s)
- Galyna V Graham
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland BT52 1SA, UK
| | - Andrew McCloskey
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland BT52 1SA, UK
| | - Yasser H Abdel-Wahab
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland BT52 1SA, UK
| | - J Michael Conlon
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland BT52 1SA, UK.
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland BT52 1SA, UK
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Lafferty RA, Gault VA, Flatt PR, Irwin N. Effects of 2 Novel PYY(1-36) Analogues, (P 3L 31P 34)PYY(1-36) and PYY(1-36)(Lys 12PAL), on Pancreatic Beta-Cell Function, Growth, and Survival. CLINICAL MEDICINE INSIGHTS-ENDOCRINOLOGY AND DIABETES 2019; 12:1179551419855626. [PMID: 31244528 PMCID: PMC6580715 DOI: 10.1177/1179551419855626] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 05/15/2019] [Indexed: 12/14/2022]
Abstract
Recent studies have identified a beneficial role for peptide tyrosine tyrosine
(PYY) on pancreatic beta-cell function and survival. These effects are linked to
the activation of neuropeptide Y1 receptors (NPYR1s) by PYY(1-36). However,
PYY(1-36) is subject to rapid degradation by dipeptidyl peptidase-4 (DPP-4),
resulting is the loss of NPYR1 activity. Therefore, the aim of this study was to
develop 2 enzymatically stable PYY(1-36) analogues, namely,
(P3L31P34)PYY(1-36) and
PYY(1-36)(Lys12PAL), with further structural modifications to
enhance NPYR1 specificity. As expected,
(P3L31P34)PYY(1-36) was fully resistant to
DPP-4-mediated degradation in vitro, whereas PYY(1-36) and
PYY(1-36)(Lys12PAL) were both liable to DPP-4 breakdown.
PYY(1-36) and (P3L31P34)PYY(1-36) induced
significant reductions in glucose-stimulated insulin secretion (GSIS) from BRIN
BD11 cells, but only PYY(1-36) diminished alanine-stimulated insulin secretion.
In contrast, PYY(1-36)(Lys12PAL) had no impact on GSIS or
alanine-induced insulin release. All 3 PYY peptides significantly enhanced
proliferation in BRIN BD11 and 1.1B4 beta-cell lines, albeit only at the highest
concentration examined, 10-6 M, for
(P3L31P34)PYY(1-36) and
PYY(1-36)(Lys12PAL) in BRIN BD11 cells. Regarding the protection
of beta-cells against cytokine-induced apoptosis, PYY(1-36) induced clear
protective effects. Both (P3L31P34)PYY(1-36)
and PYY(1-36)(Lys12PAL) offered some protection against apoptosis in
BRIN BD11 cells, but were significantly less efficacious than PYY(1-36).
Similarly, in 1.1B4 cells, both PYY analogues (10-6 M) protected
against cytokine-induced apoptosis, but
(P3L31P34)PYY(1-36) was significantly less
effective than PYY(1-36). All 3 PYY peptides had no impact on refeeding in
overnight fasted mice. These data underline the beta-cell benefits of PYY(1-36)
and highlight the challenges of synthesising stable, bioactive, NPYR1-specific,
PYY(1-36) analogues.
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Affiliation(s)
- Ryan A Lafferty
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK.,Diabetes Research Group, University of Ulster, Coleraine, UK
| | - Victor A Gault
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK
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Lafferty RA, Flatt PR, Irwin N. C-terminal degradation of PYY peptides in plasma abolishes effects on satiety and beta-cell function. Biochem Pharmacol 2018; 158:95-102. [PMID: 30292757 DOI: 10.1016/j.bcp.2018.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/03/2018] [Indexed: 02/08/2023]
Abstract
The importance of dipeptidyl peptidase-4 mediated N-terminal metabolism of the enteroendocrine-derived hormone, peptide YY (PYY), for receptor binding and subsequent biological action profile is well established. However, an intact C-terminus may be fundamental also for bioactivity of PYY peptides. The current study has demonstrated C-terminal degradation of the major recognised circulating forms of PYY, PYY(1-36) and PYY(3-36), in plasma, resulting in production of PYY(1-34) and PYY(3-34). Interestingly, the angiotensin-converting-enzyme (ACE) inhibitor, captopril, blocked formation of PYY(3-34) from PYY(3-36) in plasma, but did result in the appearance of PYY(3-35). In addition, we were able to evidence C-terminal truncation of PYY(1-35) and PYY(3-35) to PYY(1-34) and PYY(3-34), respectively. As expected, PYY(1-36) and PYY(3-36) inhibited (P < 0.05-P < 0.001) glucose- and alanine-stimulated insulin secretion from BRIN-BD11 beta-cells. In contrast, PYY(1-34), PYY(3-34), PYY(1-35) and PYY(3-35) were devoid of insulinostatic actions. Both PYY(1-36) and PYY(3-36), but not related PYY metabolites, significantly (P < 0.05-P < 0.001) enhanced proliferation of BRIN BD11 and 1.1B4 beta-cell lines, and protected (P < 0.01-P < 0.001) these cell lines against cytokine-induced apoptosis. As expected, PYY(3-36) induced clear (P < 0.05-P < 0.01) appetite suppressive effects in mice, but this action was eliminated by mono- or di-peptide C-terminal truncation. Interestingly, captopril significantly (P < 0.05) augmented the anorexigenic effects of PYY(3-36) in mice. PYY(1-36), PYY(3-36), PYY(1-34) and PYY(3-34) lacked effects on in vivo glucose tolerance or glucose-induced insulin release. Taken together, these data highlight the unrecognised importance of C-terminal integrity of PYY peptides for biological activity and therapeutic usefulness in obesity-diabetes.
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Affiliation(s)
- R A Lafferty
- 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
| | - N Irwin
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, UK.
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18
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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] [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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Willekens SMA, Joosten L, Boerman OC, Brom M, Gotthardt M. Characterization of 111In-labeled Glucose-Dependent Insulinotropic Polypeptide as a Radiotracer for Neuroendocrine Tumors. Sci Rep 2018; 8:2948. [PMID: 29440684 PMCID: PMC5811606 DOI: 10.1038/s41598-018-21259-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 01/31/2018] [Indexed: 12/04/2022] Open
Abstract
Somatostatin receptor targeting is considered the standard nuclear medicine technique for visualization of neuroendocrine tumors (NET). Since not all NETs over-express somatostatin receptors, the search for novel targets, visualizing these NETs, is ongoing. Many NETs, expressing low somatostatin receptor levels, express glucose-dependent insulinotropic polypeptide (GIP) receptors (GIPR). Here, we evaluated the performance of [Lys37(DTPA)]N-acetyl-GIP1-42, a newly synthesized GIP analogue to investigate whether NET imaging via GIPR targeting is feasible. Therefore, [Lys37(DTPA)]N-acetyl-GIP1-42 was radiolabeled with 111In with specific activity up to 1.2 TBq/µmol and both in vitro and in vivo receptor targeting properties were examined. In vitro, [Lys37(111In-DTPA)]N-acetyl-GIP1-42 showed receptor-mediated binding to BHK-GIPR positive cells, NES2Y cells and isolated islets. In vivo, both NES2Y and GIPR-transfected BHK tumors were visualized on SPECT/CT. Furthermore, co-administration of an excess unlabeled GIP1-42 lowered tracer uptake from 0.7 ± 0.2%ID/g to 0.6 ± 0.01%ID/g (p = 0.78) in NES2Y tumors and significantly lowered tracer uptake from 3.3 ± 0.8 to 0.8 ± 0.2%ID/g (p = 0.0001) in GIPR-transfected BHK tumors. In conclusion, [Lys37(111In-DTPA)]N-acetyl-GIP1-42 shows receptor-mediated binding in various models. Furthermore, both GIPR-transfected BHK tumors and NES2Y tumors were visible on SPECT/CT using this tracer. Therefore, [Lys37(111In-DTPA)]N-acetyl-GIP1-42 SPECT seems promising for visualization of somatostatin receptor negative NETs.
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Affiliation(s)
- Stefanie M A Willekens
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands. .,Division of Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University Hospitals and KU Leuven, Leuven, Belgium.
| | - Lieke Joosten
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Otto C Boerman
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Maarten Brom
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Martin Gotthardt
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
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Abstract
OBJECTIVES Modulation of cholecystokinin (CCK) receptors has been shown to influence pancreatic endocrine function. METHODS We assessed the impact of the CCKA and CCKB receptor modulators, (pGlu-Gln)-CCK-8 and gastrin-17, respectively, on β-cell secretory function, proliferation and apoptosis and glucose tolerance, and investigating alterations of CCK and gastrin islet expression in diabetes. RESULTS Initially, the presence of CCK and gastrin, and expression of their receptors were evidenced in β-cell lines and mouse islets. (pGlu-Gln)-CCK-8 and gastrin-17 stimulated insulin secretion from BRIN-BD11 and 1.1B4 β-cells, associated with no effect on membrane potential or [Ca]i. Only (pGlu-Gln)-CCK-8 possessed insulin secretory actions in isolated islets. In agreement, (pGlu-Gln)-CCK-8 improved glucose disposal and glucose-induced insulin release in mice. In addition, (pGlu-Gln)-CCK-8 evoked clear satiety effects. Interestingly, islet colocalization of CCK with glucagon was elevated in streptozotocin- and hydrocortisone-induced diabetic mice, whereas gastrin coexpression in α cells was reduced. In contrast, gastrin colocalization within β-cells was higher in diabetic mice, while CCK coexpression with insulin was decreased in insulin-deficient mice. (pGlu-Gln)-CCK-8 and gastrin-17 also augmented human and rodent β-cell proliferation and offered protection against streptozotocin-induced β-cell cytotoxicity. CONCLUSIONS We highlight the direct involvement of CCKA and CCKB receptors in pancreatic β-cell function and survival.
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Gasbjerg LS, Gabe MBN, Hartmann B, Christensen MB, Knop FK, Holst JJ, Rosenkilde MM. Glucose-dependent insulinotropic polypeptide (GIP) receptor antagonists as anti-diabetic agents. Peptides 2018; 100:173-181. [PMID: 29412817 DOI: 10.1016/j.peptides.2017.11.021] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 11/27/2017] [Accepted: 11/28/2017] [Indexed: 01/07/2023]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is an intestinal hormone with a broad range of physiological actions. In the postprandial state, the hormone stimulates insulin secretion and during eu- and hypoglycemia, it stimulates glucagon secretion. In addition, GIP increases triacylglycerol (TAG) uptake in adipose tissue and decreases bone resorption. However, the importance of these actions in humans are not clearly understood as a specific GIP receptor (GIPR) antagonist - an essential tool to study GIP physiology - has been missing. Several different GIPR antagonists have been identified comprising both peptides, vaccines against GIP, GIP antibodies or antibodies against the GIPR. However, most of these have only been tested in rodents. In vitro, N- and C-terminally truncated GIP variants are potent and efficacious GIPR antagonists. Recently, GIP(3-30)NH2, a naturally occurring peptide, was shown to block the GIPR in humans and decrease GIP-induced insulin secretion as well as adipose tissue blood flow and TAG uptake. So far, there are no studies with a GIPR antagonist in patients with type 2 diabetes (T2D), but because the elevations in fasting plasma glucagon and paradoxical postprandial glucagon excursions, seen in patients with T2D, are aggravated by GIP, a GIPR antagonist could partly alleviate this and possibly improve the fasting and postprandial glycemia. Since the majority of patients with T2D are overweight, inhibition of GIP-induced fat deposition may be beneficial as well. Here we summarize the studies of GIPR antagonists and discuss the therapeutic potential of the GIP system in humans.
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Affiliation(s)
- Lærke Smidt Gasbjerg
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.
| | - Maria Buur Nordskov Gabe
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bolette Hartmann
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mikkel Bring Christensen
- Center for Diabetes 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
| | - Filip Krag Knop
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Juul Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette Marie Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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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] [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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Singh AK, Jatwa R, Purohit A, Ram H. Synthetic and phytocompounds based dipeptidyl peptidase-IV (DPP-IV) inhibitors for therapeutics of diabetes. JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH 2017; 19:1036-1045. [PMID: 28351157 DOI: 10.1080/10286020.2017.1307183] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 03/13/2017] [Indexed: 06/06/2023]
Abstract
Currently antidiabetic therapeutic strategies are mainly based on synthetic hypoglycemic agent. Antidiabetic drugs are associated with significant adverse effects of hypoglycemia, dysfunction of insulin and weight gain. Nowadays, the novel Dipeptidyl peptidase-IV (DPP-IV) inhibitors unique approach for the management of diabetes has been considered to be safe, as DPP-IV inhibitors reduce blood glucose level by monitoring hyperglycemia including positive effects on body weight as it remains neutral, improves glycated hemoglobin levels and do not induce hypoglycemia. Inhibitors help to protect degradation of Glucagon-like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP), gut hormones which helps to suppresses postprandial glucagon release, delay gastric emptying and regulate satiety. Therefore, the innovation of DPP-IV inhibitor based drugs regulates activity of incretin hormones such as GLP-1 and GIP. Commercially available DPP-IV inhibitors are chemically synthesized with good therapeutic value. However, the durability and long-term safety of DPP-IV inhibitors remains to be established. On the other hand, phytocompounds-based DPP-IV inhibitors are alternative and safe to use as compared to synthetic. Numerous novel antidiabetic compounds and group of compounds emerging in clinical development are through DPP-IV inhibition. This review summarized recent progress made on DPP-IV inhibitors from both synthetic as well as from natural sources.
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Affiliation(s)
- Anand-Krishna Singh
- a Animal Physiology Lab, Department of Zoology , Jai Narain Vyas University , Jodhpur 342001 , India
| | - Rameshwar Jatwa
- b Molecular Medicine and Toxicology Lab, School of Life Sciences , Devi Ahilya University , Indore 452001 , India
| | - Ashok Purohit
- a Animal Physiology Lab, Department of Zoology , Jai Narain Vyas University , Jodhpur 342001 , India
| | - Heera Ram
- a Animal Physiology Lab, Department of Zoology , Jai Narain Vyas University , Jodhpur 342001 , India
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Vasu S, Ojo OO, Moffett RC, Conlon JM, Flatt PR, Abdel-Wahab YHA. Anti-diabetic actions of esculentin-2CHa(1–30) and its stable analogues in a diet-induced model of obesity-diabetes. Amino Acids 2017; 49:1705-1717. [DOI: 10.1007/s00726-017-2469-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 07/19/2017] [Indexed: 12/16/2022]
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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] [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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Khan D, Vasu S, Moffett RC, Irwin N, Flatt PR. Influence of neuropeptide Y and pancreatic polypeptide on islet function and beta-cell survival. Biochim Biophys Acta Gen Subj 2017; 1861:749-758. [PMID: 28069397 DOI: 10.1016/j.bbagen.2017.01.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/03/2017] [Accepted: 01/04/2017] [Indexed: 01/06/2023]
Abstract
BACKGROUND In the present study we assessed the impact of neuropeptide Y receptor (NPYR) modulators, neuropeptide Y (NPY) and pancreatic polypeptide (PP), on islet function and beta-cell survival. METHODS The effects of NPY and PP on beta-cell function were examined in BRIN BD11 and 1.1B4 beta-cells, as well as isolated mouse islets. Involvement of both peptides in pancreatic islet adaptations to streptozotocin and hydrocortisone, as well as effects on beta-cell proliferation and apoptosis was also evaluated. RESULTS Neither NPY nor PP affected in vivo glucose disposal or insulin secretion in mice. However, both peptides inhibited (p<0.05 to p<0.001) glucose stimulated insulin secretion from rat and human beta-cells. NPY exerted similar insulinostatic effects in isolated mouse islets. NPY and PP inhibited alanine-induced changes in BRIN BD11 cell membrane potential and (Ca2+)i. Streptozotocin treatment decreased and hydrocortisone treatment increased beta-cell mass in mice. In addition, streptozotocin, but not hydrocortisone, increased PP cell area. Streptozotocin also shifted the normal co-localisation of NPY with PP, towards more pronounced co-expression with somatostatin in delta-cells. Both streptozotocin and hydrocortisone increased pancreatic exocrine expression of NPY. More detailed in vitro investigations revealed that NPY, but not PP, augmented (p<0.01) BRIN BD11 beta-cell proliferation. In addition, both peptides exerted protective effects against streptozotocin-induced DNA damage in beta-cells. CONCLUSION These data emphasise the involvement of PP, and particularly NPY, in the regulation of beta-cell mass and function. GENERAL SIGNIFICANCE Modulation of PP and NPY signalling is suitable for further evaluation and possible clinical development for the treatment of diabetes.
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Affiliation(s)
- Dawood Khan
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Srividya Vasu
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - R Charlotte Moffett
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK.
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
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27
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Khan D, Vasu S, Moffett RC, Irwin N, Flatt PR. Islet distribution of Peptide YY and its regulatory role in primary mouse islets and immortalised rodent and human beta-cell function and survival. Mol Cell Endocrinol 2016; 436:102-13. [PMID: 27465830 DOI: 10.1016/j.mce.2016.07.020] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 07/18/2016] [Accepted: 07/19/2016] [Indexed: 12/25/2022]
Abstract
Recent evidence suggests that the classic gut peptide, Peptide YY (PYY), could play a fundamental role in endocrine pancreatic function. In the present study expression of PYY and its NPY receptors on mouse islets and immortalised rodent and human beta-cells was examined together with the effects of both major circulating forms of PYY, namely PYY(1-36) and PYY(3-36), on beta-cell function, murine islet adaptions to insulin deficiency/resistance, as well as direct effects on cultured beta-cell proliferation and apoptosis. In vivo administration of PYY(3-36), but not PYY(1-36), markedly (p < 0.05) decreased food intake in overnight fasted mice. Neither form of PYY affected glucose disposal or insulin secretion following an i.p. glucose challenge. However, in vitro, PYY(1-36) and PYY(3-36) inhibited (p < 0.05 to p < 0.001) glucose, alanine and GLP-1 stimulated insulin secretion from immortalised rodent and human beta-cells, as well as isolated mouse islets, by impeding alterations in membrane potential, [Ca(2+)]i and elevations of cAMP. Mice treated with multiple low dose streptozotocin presented with severe (p < 0.01) loss of beta-cell mass accompanied by notable increases (p < 0.001) in alpha and PP cell numbers. In contrast, hydrocortisone-induced insulin resistance increased islet number (p < 0.01) and beta-cell mass (p < 0.001). PYY expression was consistently observed in alpha-, PP- and delta-, but not beta-cells. Streptozotocin decreased islet PYY co-localisation with PP (p < 0.05) and somatostatin (p < 0.001), whilst hydrocortisone increased PYY co-localisation with glucagon (p < 0.05) in mice. More detailed in vitro investigations revealed that both forms of PYY augmented (p < 0.05 to p < 0.01) immortalised human and rodent beta-cell proliferation and protected against streptozotocin-induced cytotoxicity, to a similar or superior extent as the well characterised beta-cell proliferative and anti-apoptotic agent GLP-1. Taken together, these data highlight the significance and potential offered by modulation of pancreatic islet NPY receptor signalling pathways for preservation of beta-cell mass in diabetes.
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Affiliation(s)
- Dawood Khan
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Srividya Vasu
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - R Charlotte Moffett
- 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.
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
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Wilding JPH, Rajeev SP, DeFronzo RA. Positioning SGLT2 Inhibitors/Incretin-Based Therapies in the Treatment Algorithm. Diabetes Care 2016; 39 Suppl 2:S154-64. [PMID: 27440828 DOI: 10.2337/dcs15-3005] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are the most recent addition to the therapeutic options available for the treatment of type 2 diabetes and became available after the introduction of incretin-based therapies, dipeptidyl peptidase 4 inhibitors and glucagon-like peptide 1 receptor agonists (GLP-1 RAs). These agents have potential advantages with regard to their weight loss-promoting effect, low risk of hypoglycemia, reduction in blood pressure, and reduction in cardiovascular events in high-risk patients (with empagliflozin). Apart from these clinically important outcomes, they may also correct core defects present in type 2 diabetes (i.e., improvement in β-cell function and insulin sensitivity). They do, however, have some adverse effects, notably, nausea with GLP-1 RAs and genital tract infections and potential for volume depletion with SGLT2i. Whether incretin-based therapies are associated with an increased risk of pancreatitis is unclear. Most recently, diabetic ketoacidosis has been reported with SGLT2i. Therefore, a key clinical question in relation to guidelines is whether these clinical advantages, in the context of the adverse effect profile, outweigh the additional cost compared with older, more established therapies. This article reviews the therapeutic rationale for the use of these newer drugs for diabetes treatment, considers their place in current guidelines, and discusses how this may change as new data emerge about their long-term efficacy and safety from ongoing outcome trials.
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Affiliation(s)
- John P H Wilding
- Obesity and Endocrinology Clinical Research, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, U.K.
| | - Surya Panicker Rajeev
- Obesity and Endocrinology Clinical Research, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, U.K
| | - Ralph A DeFronzo
- Diabetes Division, The University of Texas Health Science Center at San Antonio, San Antonio, TX
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Hansen LS, Sparre-Ulrich AH, Christensen M, Knop FK, Hartmann B, Holst JJ, Rosenkilde MM. N-terminally and C-terminally truncated forms of glucose-dependent insulinotropic polypeptide are high-affinity competitive antagonists of the human GIP receptor. Br J Pharmacol 2016; 173:826-38. [PMID: 26572091 PMCID: PMC4761099 DOI: 10.1111/bph.13384] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 10/13/2015] [Accepted: 10/16/2015] [Indexed: 12/25/2022] Open
Abstract
Background and Purpose Glucose‐dependent insulinotropic polypeptide (GIP) affects lipid, bone and glucose homeostasis. High‐affinity ligands for the GIP receptor are needed to elucidate the physiological functions and pharmacological potential of GIP in vivo. GIP(1–30)NH2 is a naturally occurring truncation of GIP(1–42). Here, we have characterized eight N‐terminal truncations of human GIP(1–30)NH2. Experimental Approach COS‐7 cells were transiently transfected with human GIP receptors and assessed for cAMP accumulation upon ligand stimulation or competition binding with 125I‐labelled GIP(1–42), GIP(1–30)NH2, GIP(2–30)NH2 or GIP(3–30)NH2. Key Results GIP(1–30)NH2 displaced 125I‐GIP(1–42) as effectively as GIP(1–42) (Ki 0.75 nM), whereas the eight truncations displayed lower affinities (Ki 2.3–347 nM) with highest affinities for GIP(3–30)NH2 and GIP(5–30)NH2 (5–30)NH2. Only GIP(1–30)NH2 (Emax 100% of GIP(1–42)) and GIP(2–30)NH2 (Emax 20%) were agonists. GIP(2‐ to 9–30)NH2 displayed antagonism (IC50 12–450 nM) and Schild plot analyses identified GIP(3–30)NH2 and GIP(5–30)NH2 as competitive antagonists (Ki 15 nM). GIP(3–30) NH2 was a 26‐fold more potent antagonist than GIP(3–42). Binding studies with agonist (125I‐GIP(1–30)NH2), partial agonist (125I‐GIP(2–30)NH2) and competitive antagonist (125I‐GIP(3–30)NH2) revealed distinct receptor conformations for these three ligand classes. Conclusions and Implications The N‐terminus is crucial for GIP agonist activity. Removal of the C‐terminus of the endogenous GIP(3–42) creates another naturally occurring, more potent, antagonist GIP(3–30)NH2, which like GIP(5–30)NH2, was a high‐affinity competitive antagonist. These peptides may be suitable tools for basic GIP research and future pharmacological interventions.
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Affiliation(s)
- L S Hansen
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark
| | - A H Sparre-Ulrich
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - M Christensen
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark
| | - F K Knop
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark
| | - B Hartmann
- NNF Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - J J Holst
- NNF Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - M M Rosenkilde
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Irwin N, Flatt PR. New perspectives on exploitation of incretin peptides for the treatment of diabetes and related disorders. World J Diabetes 2015; 6:1285-1295. [PMID: 26557956 PMCID: PMC4635139 DOI: 10.4239/wjd.v6.i15.1285] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 09/25/2015] [Accepted: 10/27/2015] [Indexed: 02/05/2023] Open
Abstract
The applicability of stable gut hormones for the treatment of obesity-related diabetes is now undisputable. This is based predominantly on prominent and sustained glucose-lowering actions, plus evidence that these peptides can augment insulin secretion and pancreatic islet function over time. This review highlights the therapeutic potential of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), oxyntomodulin (OXM) and cholecystokinin (CCK) for obesity-related diabetes. Stable GLP-1 mimetics have already been successfully adopted into the diabetic clinic, whereas GIP, CCK and OXM molecules offer promise as potential new classes of antidiabetic drugs. Moreover, recent studies have shown improved therapeutic effects following simultaneous modulation of multiple receptor signalling pathways by combination therapy or use of dual/triple agonist peptides. However, timing and composition of injections may be important to permit interludes of beta-cell rest. The review also addresses the possible perils of incretin based drugs for treatment of prediabetes. Finally, the unanticipated utility of stable gut peptides as effective treatments for complications of diabetes, bone disorders, cognitive impairment and cardiovascular dysfunction is considered.
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