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Tanday N, Zhu W, Tarasov AI, Flatt PR, Irwin N. [P 3]PP, a stable, long-acting pancreatic polypeptide analogue, evokes weight lowering and pancreatic beta-cell-protective effects in obesity-associated diabetes. Diabetes Obes Metab 2024; 26:4945-4957. [PMID: 39192525 DOI: 10.1111/dom.15897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Revised: 08/07/2024] [Accepted: 08/07/2024] [Indexed: 08/29/2024]
Abstract
AIM To thoroughly investigate the impact of sustained neuropeptide Y4 receptor (NPY4R) activation in obesity-associated diabetes. METHODS Initially, the prolonged pharmacodynamic profile of the enzymatically stable pancreatic polypeptide (PP) analogue, [P3]PP, was confirmed in normal mice up to 24 h after injection. Subsequent to this, [P3]PP was administered twice daily (25 nmol/kg) for 28 days to high-fat-fed mice with streptozotocin-induced insulin deficiency, known as HFF/STZ mice. RESULTS Treatment with [P3]PP for 28 days reduced energy intake and was associated with notable weight loss. In addition, circulating glucose was returned to values of approximately 8 mmol/L in [P3]PP-treated mice, with significantly increased plasma insulin and decreased glucagon concentrations. Glucose tolerance and glucose-stimulated insulin secretion were improved in [P3]PP-treated HFF/STZ mice, with no obvious effect on peripheral insulin sensitivity. Benefits on insulin secretion were associated with elevated pancreatic insulin content as well as islet and beta-cell areas. Positive effects on islet architecture were linked to increased beta-cell proliferation and decreased apoptosis. Treatment intervention also decreased islet alpha-cell area, but pancreatic glucagon content remained unaffected. In addition, [P3]PP-treated HFF/STZ mice presented with reduced plasma alanine transaminase and aspartate transaminase levels, with no change in circulating amylase concentrations. In terms of plasma lipid profile, triglyceride and cholesterol levels were significantly decreased by [P3]PP treatment, when compared to saline controls. CONCLUSION Collectively, these data highlight for the first time the potential of enzymatically stable PP analogues for the treatment of obesity and related diabetes.
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Affiliation(s)
- Neil Tanday
- Diabetes Research Centre, Ulster University, Coleraine, UK
| | - Wuyun Zhu
- Diabetes Research Centre, Ulster University, Coleraine, UK
| | | | - Peter R Flatt
- Diabetes Research Centre, Ulster University, Coleraine, UK
| | - Nigel Irwin
- Diabetes Research Centre, Ulster University, Coleraine, UK
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2
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Ali A, Flatt PR, Irwin N. Gut-Derived Peptide Hormone Analogues and Potential Treatment of Bone Disorders in Obesity and Diabetes Mellitus. Clin Med Insights Endocrinol Diabetes 2024; 17:11795514241238059. [PMID: 38486712 PMCID: PMC10938612 DOI: 10.1177/11795514241238059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 02/14/2024] [Indexed: 03/17/2024] Open
Abstract
Obesity and diabetes mellitus are prevalent metabolic disorders that have a detrimental impact on overall health. In this regard, there is now a clear link between these metabolic disorders and compromised bone health. Interestingly, both obesity and diabetes lead to elevated risk of bone fracture which is independent of effects on bone mineral density (BMD). In this regard, gastrointestinal (GIT)-derived peptide hormones and their related long-acting analogues, some of which are already clinically approved for diabetes and/or obesity, also seem to possess positive effects on bone remodelling and microarchitecture to reduce bone fracture risk. Specifically, the incretin peptides, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), as well as glucagon-like peptide-2 (GLP-2), exert key direct and/or indirect benefits on bone metabolism. This review aims to provide an initial appraisal of the relationship between obesity, diabetes and bone, with a focus on the positive impact of these GIT-derived peptide hormones for bone health in obesity/diabetes. Brief discussion of related peptides such as parathyroid hormone, leptin, calcitonin and growth hormone is also included. Taken together, drugs engineered to promote GIP, GLP-1 and GLP-2 receptor signalling may have potential to offer therapeutic promise for improving bone health in obesity and diabetes.
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Affiliation(s)
- Asif Ali
- 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
| | - Nigel Irwin
- Diabetes Research Centre, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, UK
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Bulushova NV, Zalunin IA, Asrarkulova AS, Kozlov DG. Incretin Analogues in the Therapy of Type 2 Diabetes and Obesity. APPL BIOCHEM MICRO+ 2022. [DOI: 10.1134/s0003683822070031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Franklin ZJ, Lafferty RA, Flatt PR, McShane LM, O'Harte FP, Irwin N. Metabolic effects of combined glucagon receptor antagonism and glucagon-like peptide-1 receptor agonism in high fat fed mice. Biochimie 2022; 199:60-67. [DOI: 10.1016/j.biochi.2022.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/05/2022] [Accepted: 04/13/2022] [Indexed: 01/19/2023]
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Komati A, Anand A, Shaik H, Mudiam MKR, Suresh Babu K, Tiwari AK. Bombax ceiba (Linn.) calyxes ameliorate methylglyoxal-induced oxidative stress via modulation of RAGE expression: identification of active phytometabolites by GC-MS analysis. Food Funct 2021; 11:5486-5497. [PMID: 32500907 DOI: 10.1039/c9fo02714a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Non-enzymatic reactions between proteins and methylglyoxal (MG) result in the formation of advanced glycation end products (AGEs). These AGEs play a vital role in the development of diabetic complications by stimulating oxidative stress and acting upon their receptor RAGE (Receptor for Advanced Glycation End products). This study examined the effect of aqueous methanol extract of Bombax ceiba L. calyxes (BCCE) on MG induced protein glycation and oxidative stress, followed by the identification of phytometabolites present in the calyxes using gas chromatography-mass spectrometry (GC-MS). The study revealed that priming of bovine serum albumin protein with the BCCE inhibited MG induced AGE formation in vitro and restrained AGE-induced RAGE up-regulation in HEK-293 cells. The BCCE significantly (p < 0.001) reduced the MG induced increase in reactive oxygen species (ROS), NADPH oxidase (NOX), and mitochondrial dysfunction. Improvements in the levels of antioxidant enzymes such as Mn and Cu/Zn-superoxide dismutase and glutathione reductase were also observed in HEK-293 cells. Furthermore, the decrease in primary cellular defense against AGEs, the glyoxalase 1 (Glo-1) activity, due to MG treatment was restored in BCCE treated cells. GC-MS analysis revealed the presence of antioxidant and antiglycation compounds such as myo-ionisitol, scopoletin, d-sedoheptulose, succinic acid, and xylitol in B. ceiba calyxes. The observed beneficial effect in our study might be attributed to the presence of these compounds in B. Ceiba calyxes. This is the first report presenting the antioxidant and antiglycation activities of B. ceiba calyxes and GC-MS analysis of active phytometabolites. These observations show that B. ceiba calyxes may become a potent and promising functional food to manage/control the development of diabetic complications.
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Affiliation(s)
- Anusha Komati
- Centre for Natural Products & Traditional Knowledge, CSIR Indian Institute of Chemical Technology, Hyderabad-500007, India. and Academy of Scientific & Innovative Research, CSIR Indian Institute of Chemical Technology, Hyderabad-500007, India
| | - Ajay Anand
- Centre for Natural Products & Traditional Knowledge, CSIR Indian Institute of Chemical Technology, Hyderabad-500007, India. and Academy of Scientific & Innovative Research, CSIR Indian Institute of Chemical Technology, Hyderabad-500007, India
| | - Hussain Shaik
- Academy of Scientific & Innovative Research, CSIR Indian Institute of Chemical Technology, Hyderabad-500007, India and Department of Analytical & Structural Chemistry, CSIR Indian Institute of Chemical Technology, Hyderabad-500007, India
| | - Mohana Krishna Reddy Mudiam
- Academy of Scientific & Innovative Research, CSIR Indian Institute of Chemical Technology, Hyderabad-500007, India and Department of Analytical & Structural Chemistry, CSIR Indian Institute of Chemical Technology, Hyderabad-500007, India
| | - Katragadda Suresh Babu
- Centre for Natural Products & Traditional Knowledge, CSIR Indian Institute of Chemical Technology, Hyderabad-500007, India. and Academy of Scientific & Innovative Research, CSIR Indian Institute of Chemical Technology, Hyderabad-500007, India
| | - Ashok Kumar Tiwari
- Centre for Natural Products & Traditional Knowledge, CSIR Indian Institute of Chemical Technology, Hyderabad-500007, India. and Academy of Scientific & Innovative Research, CSIR Indian Institute of Chemical Technology, Hyderabad-500007, India
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Bailey CJ. GIP analogues and the treatment of obesity-diabetes. Peptides 2020; 125:170202. [PMID: 31756366 DOI: 10.1016/j.peptides.2019.170202] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/09/2019] [Accepted: 11/11/2019] [Indexed: 12/18/2022]
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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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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8
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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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Hasib A, Ng MT, Tanday N, Craig SL, Gault VA, Flatt PR, Irwin N. Exendin-4(Lys 27 PAL)/gastrin/xenin-8-Gln: A novel acylated GLP-1/gastrin/xenin hybrid peptide that improves metabolic status in obese-diabetic (ob/ob) mice. Diabetes Metab Res Rev 2019; 35:e3106. [PMID: 30499633 DOI: 10.1002/dmrr.3106] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/19/2018] [Accepted: 11/27/2018] [Indexed: 12/27/2022]
Abstract
BACKGROUND Therapeutic benefits of peptide-based drugs is limited by rapid renal elimination. METHODS Therefore, to prolong the biological action profile of the recently characterized triple-acting hybrid peptide, exendin-4/gastrin/xenin-8-Gln, a fatty acid (C-16) has been covalently attached, creating exendin-4(Lys27 PAL)/gastrin/xenin-8-Gln. Exendin-4/gastrin and liraglutide/gastrin/xenin-8-Gln were also synthesized as direct comparator peptides. RESULTS All hybrid peptides evoked significant concentration-dependent increases of insulin secretion from isolated murine islets and BRIN-BD11 cells. Following administration of peptides with glucose to mice, all hybrids significantly reduced the overall glycaemic excursion and increased insulin concentrations. In contrast to other treatments, exendin-4(Lys27 PAL)/gastrin/xenin-8-Gln displayed impressive antihyperglycaemic actions even 12 hours after administration, highlighting protracted duration of effects. Exendin-4/gastrin/xenin-8-Gln, exendin-4/gastrin, and exendin-4(Lys27 PAL)/gastrin/xenin-8-Gln were then progressed to a 31-day twice-daily treatment regimen in obese-diabetic ob/ob mice. All treatments decreased nonfasting glucose and HbA1c concentrations, as well as enhancing circulating and pancreatic insulin levels. Exendin-4/gastrin and exendin-4/gastrin/xenin-8-Gln also decreased food intake. Glucose tolerance was improved by all treatments, but only exendin-4(Lys27 PAL)/gastrin/xenin-8-Gln augmented glucose-induced insulin secretion. Interestingly, treatment regimens that included a xenin component induced clear advantages on the metabolic response to glucose-dependent insulinotropic polypeptide (GIP) and the glucose-lowering actions of insulin. CONCLUSION This study emphasizes the therapeutic promise of long-acting, multi-targeting hybrid gut peptides for type 2 diabetes.
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Affiliation(s)
- Annie Hasib
- Centre for Pharmacy and Diabetes, Ulster University, Coleraine, UK
| | - Ming T Ng
- Centre for Pharmacy and Diabetes, Ulster University, Coleraine, UK
| | - Neil Tanday
- Centre for Pharmacy and Diabetes, Ulster University, Coleraine, UK
| | - Sarah L Craig
- Centre for Pharmacy and Diabetes, Ulster University, Coleraine, UK
| | - Victor A Gault
- Centre for Pharmacy and Diabetes, Ulster University, Coleraine, UK
| | - Peter R Flatt
- Centre for Pharmacy and Diabetes, Ulster University, Coleraine, UK
| | - Nigel Irwin
- Centre for Pharmacy and Diabetes, Ulster University, Coleraine, UK
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10
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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] [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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Verma MK, Goel R, Krishnadas N, Nemmani KVS. Targeting glucose-dependent insulinotropic polypeptide receptor for neurodegenerative disorders. Expert Opin Ther Targets 2018; 22:615-628. [PMID: 29911915 DOI: 10.1080/14728222.2018.1487952] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
INTRODUCTION Incretin hormones, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide-1 (GLP-1) exert pleiotropic effects on endocrine pancreas and nervous system. Expression of GIP and GIP receptor (GIPR) in neurons, their roles in neurogenesis, synaptic plasticity, neurotransmission, and neuromodulation uniquely position GIPR for therapeutic applications in neurodegenerative disorders. GIP analogs acting as GIPR agonists attenuate neurobehavioral and neuropathological sequelae of neurodegenerative disorders in preclinical models, e.g. Alzheimer's disease (AD), Parkinson's disease (PD), and cerebrovascular disorders. Modulation of GIPR signaling offers an unprecedented approach for disease modification by arresting neuronal viability decline, enabling neuronal regeneration, and reducing neuroinflammation. Growth-promoting effects of GIP signaling and broad-based neuroprotection highlight the therapeutic potential of GIPR agonists. Areas covered: This review focuses on the role of GIPR-mediated signaling in the central nervous system in neurophysiological and neuropathological conditions. In context of neurodegeneration, the article summarizes potential of targeting GIPR signaling for neurodegenerative conditions such as AD, PD, traumatic brain injury, and cerebrovascular disorders. Expert opinion: GIPR represents a validated therapeutic target for neurodegenerative disorders. GIPR agonists impart symptomatic improvements, slowed neurodegeneration, and enhanced neuronal regenerative capacity in preclinical models. Modulation of GIPR signaling is potentially a viable therapeutic approach for disease modification in neurodegenerative disorders.
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Affiliation(s)
- Mahip K Verma
- a Department of Pharmacology, Novel Drug Discovery and Development , Lupin Limited , Pune , India
| | - Rajan Goel
- a Department of Pharmacology, Novel Drug Discovery and Development , Lupin Limited , Pune , India
| | - Nandakumar Krishnadas
- b Department of Pharmacology , Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education (MAHE) , Manipal , India
| | - Kumar V S Nemmani
- a Department of Pharmacology, Novel Drug Discovery and Development , Lupin Limited , Pune , India
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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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13
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Brandt SJ, Götz A, Tschöp MH, Müller TD. Gut hormone polyagonists for the treatment of type 2 diabetes. Peptides 2018; 100:190-201. [PMID: 29412819 PMCID: PMC5805859 DOI: 10.1016/j.peptides.2017.12.021] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/21/2017] [Accepted: 12/21/2017] [Indexed: 12/20/2022]
Abstract
Chemical derivatives of the gut-derived peptide hormone glucagon-like peptide 1 (GLP-1) are among the best-in-class pharmacotherapies to treat obesity and type 2 diabetes. However, GLP-1 analogs have modest weight lowering capacity, in the range of 5-10%, and the therapeutic window is hampered by dose-dependent side effects. Over the last few years, a new concept has emerged: combining the beneficial effects of several key metabolic hormones into a single molecular entity. Several unimolecular GLP-1-based polyagonists have shown superior metabolic action compared to GLP-1 monotherapies. In this review article, we highlight the history of polyagonists targeting the receptors for GLP-1, GIP and glucagon, and discuss recent progress in expanding of this concept to now allow targeted delivery of nuclear hormones via GLP-1 and other gut hormones, as a novel approach towards more personalized pharmacotherapies.
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Affiliation(s)
- Sara J Brandt
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748 Garching, Germany
| | - Anna Götz
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748 Garching, Germany; Department of Internal Medicine I, University Hospital RWTH Aachen, Aachen, Germany; Institute for Diabetes und Regeneration, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748, Garching, Germany
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748 Garching, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748 Garching, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany.
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14
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Abstract
The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) have attracted considerable scientific and clinical interest due largely to their insulin-releasing and glucose-lowering properties. Indeed, GLP-1-based therapies are now key treatment options for many people with diabetes worldwide. In contrast, GIP-based agents have yet to reach the clinic based primarily on the impaired insulinotropic action of GIP observed in people with diabetes. Nevertheless, GIP is a key physiological regulator of insulin secretion and stable forms of GIP show much promise in rodent models to alleviate diabetes-obesity. Recent studies suggest that GIP may have an important role to play in a combination therapeutic approach or bioengineered with other gut peptides. Moreover, recent experimental studies indicate that incretins also exert pleiotropic effects in regions of the brain associated with learning and memory, thereby supporting preclinical data demonstrating that incretin-based drugs improve cognitive function. This review article, based on the RD Lawrence Lecture presented at Diabetes UK Annual Professional Conference (2017), provides a brief overview of incretins with a major focus on GIP, the development of designer GIP analogues, and how these molecules can improve cognition. Thus, incretins can be considered as 'the intelligent hormones' and may hold the key to successfully treating the alarming rise in neurodegenerative disorders.
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Affiliation(s)
- V A Gault
- School of Biomedical Sciences, University of Ulster, Coleraine, UK
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15
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Acylated apelin-13 amide analogues exhibit enzyme resistance and prolonged insulin releasing, glucose lowering and anorexic properties. Biochem Pharmacol 2017; 146:165-173. [DOI: 10.1016/j.bcp.2017.10.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 10/02/2017] [Indexed: 12/13/2022]
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16
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O'Harte FPM, Ng MT, Lynch AM, Conlon JM, Flatt PR. Novel dual agonist peptide analogues derived from dogfish glucagon show promising in vitro insulin releasing actions and antihyperglycaemic activity in mice. Mol Cell Endocrinol 2016; 431:133-44. [PMID: 27179756 DOI: 10.1016/j.mce.2016.05.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 05/10/2016] [Accepted: 05/10/2016] [Indexed: 02/07/2023]
Abstract
The antidiabetic potential of thirteen novel dogfish glucagon derived analogues were assessed in vitro and in acute in vivo studies. Stable peptide analogues enhanced insulin secretion from BRIN-BD11 β-cells (p < 0.001) and reduced acute glycaemic responses following intraperitoneal glucose (25 nmol/kg) in healthy NIH Swiss mice (p < 0.05-p<0.001). The in vitro insulinotropic actions of [S2a]dogfish glucagon, [S2a]dogfish glucagon-exendin-4(31-39) and [S2a]dogfish glucagon-Lys(30)-γ-glutamyl-PAL, were blocked (p < 0.05-p<0.001) by the specific GLP-1 and glucagon receptor antagonists, exendin-4(9-39) and (desHis(1)Pro(4)Glu(9))glucagon amide but not by (Pro(3))GIP, indicating lack of GIP receptor involvement. These analogues dose-dependently stimulated cAMP production in GLP-1 and glucagon (p < 0.05-p<0.001) but not GIP-receptor transfected cells. They improved acute glycaemic and insulinotropic responses in high-fat fed diabetic mice and in wild-type C57BL/6J and GIPR-KO mice (p < 0.05-p<0.001), but not GLP-1R-KO mice, confirming action on GLP-1 but not GIP receptors. Overall, dogfish glucagon analogues have potential for diabetes therapy, exerting beneficial metabolic effects via GLP-1 and glucagon receptors.
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Affiliation(s)
- F P M O'Harte
- The Saad Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Co. Derry, BT52 1SA, Northern Ireland, UK.
| | - M T Ng
- The Saad Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Co. Derry, BT52 1SA, Northern Ireland, UK
| | - A M Lynch
- The Saad Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Co. Derry, BT52 1SA, Northern Ireland, UK
| | - J M Conlon
- The Saad Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Co. Derry, BT52 1SA, Northern Ireland, UK
| | - P R Flatt
- The Saad Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Co. Derry, BT52 1SA, Northern Ireland, UK
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17
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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] [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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18
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Wootten D, Miller LJ, Koole C, Christopoulos A, Sexton PM. Allostery and Biased Agonism at Class B G Protein-Coupled Receptors. Chem Rev 2016; 117:111-138. [PMID: 27040440 DOI: 10.1021/acs.chemrev.6b00049] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Class B G protein-coupled receptors (GPCRs) respond to paracrine or endocrine peptide hormones involved in control of bone homeostasis, glucose regulation, satiety, and gastro-intestinal function, as well as pain transmission. These receptors are targets for existing drugs that treat osteoporosis, hypercalcaemia, Paget's disease, type II diabetes, and obesity and are being actively pursued as targets for numerous other diseases. Exploitation of class B receptors has been limited by difficulties with small molecule drug discovery and development and an under appreciation of factors governing optimal therapeutic efficacy. Recently, there has been increasing awareness of novel attributes of GPCR function that offer new opportunity for drug development. These include the presence of allosteric binding sites on the receptor that can be exploited as drug binding pockets and the ability of individual drugs to enrich subpopulations of receptor conformations to selectively control signaling, a phenomenon termed biased agonism. In this review, current knowledge of biased signaling and small molecule allostery within class B GPCRs is discussed, highlighting areas that have progressed significantly over the past decade, in addition to those that remain largely unexplored with respect to these phenomena.
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Affiliation(s)
- Denise Wootten
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville 3052, Victoria, Australia
| | - Laurence J Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic , Scottsdale, Arizona 85259, United States
| | - Cassandra Koole
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville 3052, Victoria, Australia.,Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University , New York, New York 10065, United States
| | - Arthur Christopoulos
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville 3052, Victoria, Australia
| | - Patrick M Sexton
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville 3052, Victoria, Australia
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19
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Abstract
Insulin remains indispensable in the treatment of diabetes, but its use is hampered by its narrow therapeutic index. Although advances in peptide chemistry and recombinant DNA-based macromolecule synthesis have enabled the synthesis of structurally optimized insulin analogues, the growing epidemics of obesity and diabetes have emphasized the need for diabetes therapies that are more efficacious, safe and convenient. Accordingly, a broad set of drug candidates, targeting hyperglycaemia plus other disease abnormalities, is now progressing through the clinic. The development of an insulin therapy that is responsive to glucose concentration remains an ultimate goal, with initial prototypes now reaching the proof-of-concept stage. Simultaneously, the first alternatives to injectable delivery have progressed to registration.
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20
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O'Harte FPM, Franklin ZJ, Irwin N. Two novel glucagon receptor antagonists prove effective therapeutic agents in high-fat-fed and obese diabetic mice. Diabetes Obes Metab 2014; 16:1214-22. [PMID: 25060150 DOI: 10.1111/dom.12360] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 07/03/2014] [Accepted: 07/19/2014] [Indexed: 11/30/2022]
Abstract
AIMS To examine the effect of two novel, enzymatically stable, glucagon receptor peptide antagonists, on metabolic control in two mouse models of obesity/diabetes. METHOD The effects of twice daily i.p. administration of desHis(1)Pro(4)Glu(9)-glucagon or desHis(1)Pro(4)Glu(9)Lys(12)FA-glucagon for 10 days on metabolic control in high-fat-fed (HFF; 45% fat) and obese diabetic (ob/ob) mice were compared with saline-treated controls. RESULTS Neither analogue altered body weight or food intake in either model over 10 days; however, treatment with each peptide restored non-fasting blood glucose towards normal control values in HFF mice. Basal glucose was also reduced (p < 0.01) in desHis(1)Pro(4)Glu(9)Lys(12)FA-glucagon treated ob/ob mice by day 10, coinciding with increases (p < 0.001) in circulating insulin. At the end of the treatment period, both analogues significantly (p < 0.05-0.01) improved oral and i.p. glucose tolerance (p < 0.05) and peripheral insulin sensitivity, increased pancreatic insulin and glucagon content (p < 0.05-0.01) and decreased (p < 0.05) cholesterol levels in HFF mice. Similarly beneficial metabolic effects on oral glucose tolerance (p < 0.01) and pancreatic insulin content (p < 0.05) were observed in ob/ob mice, especially after desHis(1)Pro(4)Glu(9)Lys(12)FA-glucagon treatment. No significant differences in circulating triglycerides or aspects of indirect calorimetry were noted between peptide treatment groups and respective control HFF and ob/ob mice. Finally, glucagon-mediated elevations of glucose and insulin were significantly (p < 0.05-0.01) annulled after 10 days of desHis(1)Pro(4)Glu(9)-glucagon or desHis(1)Pro(4)Glu(9)Lys(12)FA-glucagon treatment in both animal models. CONCLUSION These data indicate that peptide-based glucagon receptor antagonists can reverse aspects of genetically and dietary-induced obesity-related diabetes.
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Affiliation(s)
- F P M O'Harte
- The Saad Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, UK
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21
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Bavec A. (Poly)peptide-based therapy for diabetes mellitus: insulins versus incretins. Life Sci 2014; 99:7-13. [PMID: 24412390 DOI: 10.1016/j.lfs.2013.12.210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/22/2013] [Accepted: 12/26/2013] [Indexed: 12/25/2022]
Abstract
Insulin therapy remains the standard of care for achieving and maintaining adequate glycemic control, especially in hospitalized patients with critical and noncritical illnesses. Insulin therapy is more effective against elevated fasting glycaemia but less in the reduction of postprandial hyperglycaemia. It is associated with a high incidence of hypoglycemia and weight gain. Contrary, GLP-1 mimetic therapy improves postprandial glycaemia without the hypoglycaemia and weight gain associated with aggressive insulin therapy. Moreover, it has the potential to reduce cardiovascular related morbidity. However, its increased immunogenicity and severe gastrointestinal adverse effects present a huge burden on patients. Thus, a right combination of basal insulin which has lowering effect on fasting plasma glucose and GLP-1 mimetic with its lowering effect on postprandial plasma glucose with minimal gastrointestinal adverse effects, seems the right therapy choice from a clinical point of view for some diabetic patients. In this article, we discuss the pros and cons of the use of insulin analogues and GLP-1 mimetics that are associated with the treatment of type 2 diabetes.
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Affiliation(s)
- Aljoša Bavec
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia.
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22
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O'Harte FPM, Franklin ZJ, Rafferty EP, Irwin N. Characterisation of structurally modified analogues of glucagon as potential glucagon receptor antagonists. Mol Cell Endocrinol 2013; 381:26-34. [PMID: 23891841 DOI: 10.1016/j.mce.2013.07.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 06/12/2013] [Accepted: 07/16/2013] [Indexed: 01/16/2023]
Abstract
Acute in vitro and in vivo biological activities of four novel structural analogues of glucagon were tested. desHis(1)Pro(4)-glucagon, desHis(1)Pro(4)Glu(9)-glucagon, desHis(1)Pro(4)Glu(9)Lys(12)FA-glucagon and desHis(1)Pro(4)Glu(9)Lys(30)FA-glucagon were stable to DPP-4 degradation and dose-dependently inhibited glucagon-mediated cAMP production (p<0.05 to p<0.001). None stimulated insulin secretion in vitro above basal levels, but all inhibited glucagon-induced insulin secretion (p<0.01 to p<0.001). In normal mice all analogues antagonised acute glucagon-mediated elevations of blood glucose (p<0.05 to p<0.001) and blocked corresponding insulinotropic responses. In high-fat fed mice, glucagon-induced increases in plasma insulin (p<0.05 to p<0.001) and glucagon-induced hyperglycaemia were blocked (p<0.05 to p<0.01) by three analogues. In obese diabetic (ob/ob) mice only desHis(1)Pro(4)Glu(9)-glucagon effectively (p<0.05 to p<0.01) inhibited both glucagon-mediated glycaemic and insulinotropic responses. desHis(1)Pro(4)-glucagon and desHis(1)Pro(4)Glu(9)-glucagon were biologically ineffective when administered 8h prior to glucagon, whereas desHis(1)Pro(4)Glu(9)Lys(12)FA-glucagon retained efficacy (p<0.01) for up to 24h. Such peptide-derived glucagon receptor antagonists have potential for type 2 diabetes therapy.
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Affiliation(s)
- F P M O'Harte
- The Saad Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Co. Londonderry BT52 1SA, Northern Ireland, United Kingdom.
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23
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Irwin N, Hunter K, Montgomery IA, Flatt PR. Comparison of independent and combined metabolic effects of chronic treatment with (pGlu-Gln)-CCK-8 and long-acting GLP-1 and GIP mimetics in high fat-fed mice. Diabetes Obes Metab 2013; 15:650-9. [PMID: 23388064 DOI: 10.1111/dom.12079] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 01/20/2013] [Accepted: 02/01/2013] [Indexed: 12/25/2022]
Abstract
AIM The incretin hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) and cholecystokinin (CCK) are gastrointestinal peptides with important physiological effects. However, rapid enzymatic degradation results in short-lived biological actions. METHODS This study has examined metabolic actions of exendin-4, GIP[mPEG] and a novel CCK-8 analogue, (pGlu-Gln)-CCK-8 as enzymatically stable forms of GLP-1, GIP and CCK, respectively. RESULTS All peptides significantly (p < 0.01-p < 0.001) stimulated insulin secretion from BRIN BD11 cells, and acute in vivo experiments confirmed prominent antihyperglycaemic and insulinotropic responses to GLP-1 or GIP receptor activation in normal mice. Twice daily injection of (pGlu-Gln)-CCK-8 alone and in combination with exendin-4 or GIP[mPEG] in high fat-fed mice significantly decreased accumulated food intake (p < 0.05-p < 0.01), body weight gain (p < 0.05-p < 0.01) and improved (p < 0.05) insulin sensitivity in high fat-fed mice. However, there was no evidence for superior effects compared to (pGlu-Gln)-CCK-8 alone. Combined treatment of (pGlu-Gln)-CCK-8 and exendin-4 resulted in significantly (p < 0.05) lowered circulating glucose levels and improved (p < 0.05) intraperitoneal glucose tolerance. These effects were superior to either treatment regime alone but not associated with altered insulin concentrations. A single injection of (pGlu-Gln)-CCK-8, or combined with exendin-4, significantly (p < 0.05) lowered blood glucose levels 24 h post injection in untreated high fat-fed mice. CONCLUSION This study highlights the potential of (pGlu-Gln)-CCK-8 alone and in combination with incretin hormones for the treatment of type 2 diabetes.
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Affiliation(s)
- N Irwin
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Northern Ireland, UK.
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24
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Irwin N, Montgomery IA, Flatt PR. Comparison of the metabolic effects of sustained CCK1 receptor activation alone and in combination with upregulated leptin signalling in high-fat-fed mice. Diabetologia 2013; 56:1425-35. [PMID: 23462797 DOI: 10.1007/s00125-013-2878-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 02/11/2013] [Indexed: 12/30/2022]
Abstract
AIMS/HYPOTHESIS Cholecystokinin (CCK) and leptin are important hormones with effects on energy balance. The present study assessed the biological effects of (pGlu-Gln)-CCK-8 and [D-Leu-4]-OB3, smaller isoforms of CCK and leptin, respectively. METHODS The actions and overall therapeutic use of (pGlu-Gln)-CCK-8 and [D-Leu-4]-OB3, alone and in combination, were evaluated in normal and high-fat-fed mice. RESULTS (pGlu-Gln)-CCK-8 had prominent (p < 0.01 to p < 0.001), acute feeding-suppressive effects, which were significantly augmented (p < 0.05 to p < 0.01) by [D-Leu-4]-OB3. In agreement, the acute dose-dependent glucose-lowering and insulinotropic actions of (pGlu-Gln)-CCK-8 were significantly enhanced by concurrent administration of [D-Leu-4]-OB3. Twice daily injection of (pGlu-Gln)-CCK-8 alone and in combination with [D-Leu-4]-OB3 in high-fat-fed mice for 18 days decreased body weight (p < 0.05 to p < 0.001), energy intake (p < 0.01), circulating triacylglycerol (p < 0.01), non-fasting glucose (p < 0.05 to p < 0.001) and triacylglycerol deposition in liver and adipose tissue (p < 0.001). All treatment regimens improved glucose tolerance (p < 0.05 to p < 0.001) and insulin sensitivity (p < 0.001). Combined treatment with (pGlu-Gln)-CCK-8 and [D-Leu-4]-OB3 resulted in significantly lowered plasma insulin levels, normalisation of circulating LDL-cholesterol and decreased triacylglycerol deposition in muscle. These effects were superior to either treatment regimen alone. There were no changes in overall locomotor activity or respiratory exchange ratio, but treatment with (pGlu-Gln)-CCK-8 significantly reduced (p < 0.001) energy expenditure. CONCLUSIONS/INTERPRETATION These studies highlight the potential of (pGlu-Gln)-CCK-8 alone and in combination with [D-Leu-4]-OB3 in the treatment of obesity and diabetes.
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Affiliation(s)
- N Irwin
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, BT52 2DD Northern Ireland, UK.
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25
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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] [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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26
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Irwin N, Frizelle P, O'Harte FPM, Flatt PR. (pGlu-Gln)-CCK-8[mPEG]: a novel, long-acting, mini-PEGylated cholecystokinin (CCK) agonist that improves metabolic status in dietary-induced diabetes. Biochim Biophys Acta Gen Subj 2013; 1830:4009-16. [PMID: 23583730 DOI: 10.1016/j.bbagen.2013.04.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 03/29/2013] [Accepted: 04/02/2013] [Indexed: 01/12/2023]
Abstract
BACKGROUND Cholecystokinin (CCK) is a gastrointestinal hormone that has been proposed as a potential therapeutic option for obesity-diabetes. As such, (pGlu-Gln)-CCK-8 is an N-terminally modified CCK-8 analogue with improved biological effectiveness over the native peptide. METHODS The current study has examined the in vitro stability, biological activity and in vivo therapeutic applicability of a novel second generation mini-PEGylated form of (pGlu-Gln)-CCK-8, (pGlu-Gln)-CCK-8[mPEG]. RESULTS (pGlu-Gln)-CCK-8[mPEG] was completely resistant to enzymatic degradation and in addition displayed similar insulinotropic (p<0.05 to p<0.001) and satiating effects (p<0.01 to p<0.001) as (pGlu-Gln)-CCK-8. This confirmed the capability of (pGlu-Gln)-CCK-8[mPEG] to bind to and activate the CCK receptor. Sub-chronic twice daily injection of (pGlu-Gln)-CCK-8[mPEG] in high fat fed mice for 35days significantly decreased body weight gain (p<0.05), food intake (p<0.01 to p<0.001) and triacylglycerol deposition in liver (p<0.001) and muscle (p<0.001). Furthermore, (pGlu-Gln)-CCK-8[mPEG] markedly improved intraperitoneal glucose tolerance (p<0.05) and insulin sensitivity (p<0.001). Despite this therapeutic profile, once daily injection of (pGlu-Gln)-CCK-8[mPEG] in high fat fed mice for 33days, at the same dose, was not associated with alterations in food intake and body weight. In addition, metabolic responses to exogenous glucose and insulin injection were similar to saline treated controls. CONCLUSION These studies emphasise the therapeutic potential of (pGlu-Gln)-CCK-8[mPEG] and similar molecules. GENERAL SIGNIFICANCE A more detailed analysis of the dose and administration schedule employed for (pGlu-Gln)-CCK-8[mPEG] could provide a novel and effective compound to treat obesity-diabetes.
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Affiliation(s)
- Nigel Irwin
- School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK.
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27
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Hewage CM, Venneti KC. Structural aspects of gut peptides with therapeutic potential for type 2 diabetes. ChemMedChem 2013; 8:560-7. [PMID: 23292985 DOI: 10.1002/cmdc.201200445] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Indexed: 12/25/2022]
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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28
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Irwin N, Frizelle P, O'Harte FPM, Flatt PR. Metabolic effects of activation of CCK receptor signaling pathways by twice-daily administration of the enzyme-resistant CCK-8 analog, (pGlu-Gln)-CCK-8, in normal mice. J Endocrinol 2013; 216:53-9. [PMID: 23055535 DOI: 10.1530/joe-12-0353] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cholecystokinin (CCK) is a hormone that has important physiological effects on energy balance. This study has used a stable CCK(1) receptor agonist, (pGlu-Gln)-CCK-8, to evaluate the metabolic effects of prolonged administration in normal mice. Twice-daily injection of (pGlu-Gln)-CCK-8 for 28 days resulted in significantly lowered body weights (P<0.05) on days 24 and 28, which was associated with decreased accumulated calorie intake (P<0.01) from day 12 onward. Nonfasting plasma glucose was significantly reduced (P<0.05) on day 28, while plasma insulin concentrations were increased (P<0.05). After 28 days, glucose tolerance and glucose-mediated insulin secretion were not significantly different in (pGlu-Gln)-CCK-8-treated mice. However, following a 15-min refeeding period in 18-h fasted mice, glucose levels were significantly (P<0.05) decreased by (pGlu-Gln)-CCK-8 despite similar food intake and nutrient-induced insulin levels. Insulin sensitivity in (pGlu-Gln)-CCK-8-treated mice was significantly (P<0.01) improved compared with controls. Accumulation of triacylglycerol in liver was reduced (P<0.01) but there were no differences in circulating cholesterol and triacylglycerol concentrations, as well as triacylglycerol content of pancreatic, muscle, and adipose tissue in (pGlu-Gln)-CCK-8 mice. These data highlight the beneficial metabolic effects of prolonged (pGlu-Gln)-CCK-8 administration and confirm a lack of detrimental effects.
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Affiliation(s)
- Nigel Irwin
- School of Biomedical Sciences, The SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK.
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Irwin N, Montgomery IA, Moffett RC, Flatt PR. Chemical cholecystokinin receptor activation protects against obesity-diabetes in high fat fed mice and has sustainable beneficial effects in genetic ob/ob mice. Biochem Pharmacol 2013; 85:81-91. [DOI: 10.1016/j.bcp.2012.10.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 10/08/2012] [Accepted: 10/09/2012] [Indexed: 12/17/2022]
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30
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Comparison of the independent and combined metabolic effects of subchronic modulation of CCK and GIP receptor action in obesity-related diabetes. Int J Obes (Lond) 2012. [DOI: 10.1038/ijo.2012.179] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Irwin N, Frizelle P, Montgomery IA, Moffett RC, O'Harte FPM, Flatt PR. Beneficial effects of the novel cholecystokinin agonist (pGlu-Gln)-CCK-8 in mouse models of obesity/diabetes. Diabetologia 2012; 55:2747-2758. [PMID: 22814764 DOI: 10.1007/s00125-012-2654-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 06/18/2012] [Indexed: 01/03/2023]
Abstract
AIMS/HYPOTHESIS Cholecystokinin (CCK) is a rapidly degraded gastrointestinal peptide that stimulates satiety and insulin secretion. We aimed to investigate the beneficial weight-lowering and metabolic effects of the novel N-terminally modified CCK analogue, (pGlu-Gln)-CCK-8. METHODS The biological actions of (pGlu-Gln)-CCK-8 were comprehensively evaluated in pancreatic clonal BRIN BD11 cells and in vivo in high-fat-fed and ob/ob mice. RESULTS (pGlu-Gln)-CCK-8 was completely resistant to enzymatic degradation and its satiating effects were significantly (p < 0.05 to p < 0.001) more potent than CCK-8. In BRIN-BD11 cells, (pGlu-Gln)-CCK-8 exhibited enhanced (p < 0.01 to p < 0.001) insulinotropic actions compared with CCK-8. When administered acutely to high-fat-fed or ob/ob mice, (pGlu-Gln)-CCK-8 improved glucose homeostasis. Sub-chronic twice daily injections of (pGlu-Gln)-CCK-8 in high-fat-fed mice for 28 days significantly decreased body weight (p < 0.05 to p < 0.001), accumulated food intake (p < 0.05 to p < 0.001), non-fasting glucose (p < 0.05) and triacylglycerol deposition in pancreatic (p < 0.01), adipose (p < 0.05) and liver (p < 0.001) tissue, and improved oral (p < 0.05) and i.p. (p < 0.05) glucose tolerance and insulin sensitivity (p < 0.001). Similar observations were noted in ob/ob mice given twice daily injections of (pGlu-Gln)-CCK-8. In addition, these beneficial effects were not reproduced by simple dietary restriction and were not associated with changes in energy expenditure. There was no evidence for development of tolerance to (pGlu-Gln)-CCK-8, and analysis of histology or blood-borne markers for pancreatic, liver and renal function in mice treated with (pGlu-Gln)-CCK-8 suggested little abnormal pathology. CONCLUSIONS/INTERPRETATION These studies emphasise the potential of (pGlu-Gln)-CCK-8 for the alleviation of obesity and insulin resistance.
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Affiliation(s)
- N Irwin
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, UK.
| | - P Frizelle
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, UK
| | - I A Montgomery
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, UK
| | - R C Moffett
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, UK
| | - F P M O'Harte
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, UK
| | - P R Flatt
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, UK
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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: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [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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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; 121:107-17. [PMID: 21332446 DOI: 10.1042/cs20110006] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [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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Kerr BD, Flatt AJS, Flatt PR, Gault VA. Characterization and biological actions of N-terminal truncated forms of glucose-dependent insulinotropic polypeptide. Biochem Biophys Res Commun 2010; 404:870-6. [PMID: 21184739 DOI: 10.1016/j.bbrc.2010.12.077] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 12/15/2010] [Indexed: 12/25/2022]
Abstract
The N-terminal domain of glucose-dependent insulinotropic polypeptide (GIP) plays an important role in regulating biological activity. This study examined biological properties of several N-terminal truncated forms of GIP and two novel forms with substitutions at Phe position-6 with Arg or Val. GIP(6-42), GIP(R6-42), GIP(V6-42), GIP(7-42) and GIP(9-42) stimulated cAMP production in BRIN-BD11 cells similar to native GIP, whereas responses to GIP(3-42), GIP(4-42), GIP(5-42) and GIP(8-42) were reduced (P<0.01 to P<0.001). GIP-induced cyclic AMP production was significantly inhibited by GIP(3-42), GIP(4-42), GIP(5-42), GIP(6-42), GIP(R6-42), GIP(7-42) and GIP(8-42) (P<0.001). Compared with native GIP, in vitro insulinotropic activity of GIP(3-42), GIP(4-42), GIP(5-42), GIP(7-42) and GIP(8-42) was reduced (P<0.05 to P<0.001), with GIP(4-42), GIP(5-42), GIP(7-42) and GIP(8-42) also potently inhibiting GIP-stimulated insulin secretion (P<0.001). In ob/ob mice, GIP(4-42) and GIP(8-42) increased (P<0.05 to P<0.01) plasma glucose concentrations compared to the glucose-lowering action of native GIP. When GIP(8-42) was co-administered with native GIP it countered the ability of the native peptide to lower plasma glucose and increase circulating insulin concentrations. These data confirm the importance of the N-terminal region of GIP in regulating bioactivity and reveal that sequential truncation of the peptide yields novel GIP receptor antagonists which may have functional significance.
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Affiliation(s)
- Barry D Kerr
- School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK
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Kerr BD, Flatt PR, Gault VA. (d-Ser2)Oxm[mPEG-PAL]: A novel chemically modified analogue of oxyntomodulin with antihyperglycaemic, insulinotropic and anorexigenic actions. Biochem Pharmacol 2010; 80:1727-35. [DOI: 10.1016/j.bcp.2010.08.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 08/09/2010] [Accepted: 08/12/2010] [Indexed: 01/12/2023]
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Irwin N, Gault V, Flatt PR. Therapeutic potential of the original incretin hormone glucose-dependent insulinotropic polypeptide: diabetes, obesity, osteoporosis and Alzheimer's disease? Expert Opin Investig Drugs 2010; 19:1039-48. [DOI: 10.1517/13543784.2010.513381] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Nigel Irwin
- SAAD Centre for Diabetes and Pharmacy, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, Co. Londonderry, BT52 1SA, Northern Ireland, UK ;
| | - Victor Gault
- SAAD Centre for Diabetes and Pharmacy, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, Co. Londonderry, BT52 1SA, Northern Ireland, UK ;
| | - Peter R Flatt
- SAAD Centre for Diabetes and Pharmacy, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, Co. Londonderry, BT52 1SA, Northern Ireland, UK
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Kerr BD, Flatt PR, Gault VA. Effects of γ-glutamyl linker on DPP-IV resistance, duration of action and biological efficacy of acylated glucagon-like peptide-1. Biochem Pharmacol 2010; 80:396-401. [DOI: 10.1016/j.bcp.2010.04.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 04/01/2010] [Accepted: 04/15/2010] [Indexed: 11/16/2022]
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A GIP receptor agonist exhibits beta-cell anti-apoptotic actions in rat models of diabetes resulting in improved beta-cell function and glycemic control. PLoS One 2010; 5:e9590. [PMID: 20231880 PMCID: PMC2834736 DOI: 10.1371/journal.pone.0009590] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Accepted: 02/15/2010] [Indexed: 01/09/2023] Open
Abstract
AIMS The gastrointestinal hormone GIP promotes pancreatic islet function and exerts pro-survival actions on cultured beta-cells. However, GIP also promotes lipogenesis, thus potentially restricting its therapeutic use. The current studies evaluated the effects of a truncated GIP analog, D-Ala(2)-GIP(1-30) (D-GIP(1-30)), on glucose homeostasis and beta-cell mass in rat models of diabetes. MATERIALS AND METHODS The insulinotropic and pro-survival potency of D-GIP(1-30) was evaluated in perfused pancreas preparations and cultured INS-1 beta-cells, respectively, and receptor selectivity evaluated using wild type and GIP receptor knockout mice. Effects of D-GIP(1-30) on beta-cell function and glucose homeostasis, in vivo, were determined using Lean Zucker rats, obese Vancouver diabetic fatty rats, streptozotocin treated rats, and obese Zucker diabetic fatty rats, with effects on beta-cell mass determined in histological studies of pancreatic tissue. Lipogenic effects of D-GIP(1-30) were evaluated on cultured 3T3-L1 adipocytes. RESULTS Acutely, D-GIP(1-30) improved glucose tolerance and insulin secretion. Chronic treatment with D-GIP(1-30) reduced levels of islet pro-apoptotic proteins in Vancouver diabetic fatty rats and preserved beta-cell mass in streptozotocin treated rats and Zucker diabetic fatty rats, resulting in improved insulin responses and glycemic control in each animal model, with no change in body weight. In in vitro studies, D-GIP(1-30) exhibited equivalent potency to GIP(1-42) on beta-cell function and survival, but greatly reduced action on lipoprotein lipase activity in 3T3-L1 adipocytes. CONCLUSIONS These findings demonstrate that truncated forms of GIP exhibit potent anti-diabetic actions, without pro-obesity effects, and that the C-terminus contributes to the lipogenic actions of GIP.
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