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Zhu W, Tanday N, Lafferty RA, Flatt PR, Irwin N. Novel enzyme-resistant pancreatic polypeptide analogs evoke pancreatic beta-cell rest, enhance islet cell turnover, and inhibit food intake in mice. Biofactors 2024. [PMID: 38635341 DOI: 10.1002/biof.2059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 04/02/2024] [Indexed: 04/20/2024]
Abstract
Pancreatic polypeptide (PP) is a postprandial hormone secreted from pancreatic islets that activates neuropeptide Y4 receptors (NPY4Rs). PP is known to induce satiety but effects at the level of the endocrine pancreas are less well characterized. In addition, rapid metabolism of PP by dipeptidyl peptidase-4 (DPP-4) limits the investigation of the effects of the native peptide. Therefore, in the present study, five novel amino acid substituted and/or fatty acid derivatized PP analogs were synthesized, namely [P3]PP, [K13Pal]PP, [P3,K13Pal]PP, [N-Pal]PP, and [N-Pal,P3]PP, and their impact on pancreatic beta-cell function, as well as appetite regulation and glucose homeostasis investigated. All PP analogs displayed increased resistance to DPP-4 degradation. In addition, all peptides inhibited alanine-induced insulin secretion from BRIN-BD11 beta cells. Native PP and related analogs (10-8 and 10-6 M), and especially [P3]PP and [K13Pal]PP, significantly protected against cytokine-induced beta-cell apoptosis and promoted cellular proliferation, with effects dependent on the NPY4R for all peptides barring [N-Pal,P3]PP. In mice, all peptides, except [N-Pal]PP and [N-Pal,P3]PP, evoked a dose-dependent (25, 75, and 200 nmol/kg) suppression of appetite, with native PP and [P3]PP further augmenting glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) induced reductions of food intake. The PP peptides had no obvious detrimental effect on glucose tolerance and they did not noticeably impair the glucose-regulatory actions of GLP-1 or CCK. In conclusion, Pro3 amino acid substitution of PP, either alone or together with mid-chain acylation, creates PP analogs with benefits on beta-cell rest, islet cell turnover, and energy regulation that may be applicable to the treatment of diabetes and obesity.
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Affiliation(s)
- Wuyun Zhu
- Diabetes Research Centre, Schools of Biomedical Sciences and Pharmacy & Pharmaceutical Sciences, Ulster University, Coleraine, UK
| | - Neil Tanday
- Diabetes Research Centre, Schools of Biomedical Sciences and Pharmacy & Pharmaceutical Sciences, Ulster University, Coleraine, UK
| | - Ryan A Lafferty
- Diabetes Research Centre, Schools of Biomedical Sciences and Pharmacy & Pharmaceutical Sciences, Ulster University, Coleraine, UK
| | - Peter R Flatt
- Diabetes Research Centre, Schools of Biomedical Sciences and Pharmacy & Pharmaceutical Sciences, Ulster University, Coleraine, UK
| | - Nigel Irwin
- Diabetes Research Centre, Schools of Biomedical Sciences and Pharmacy & Pharmaceutical Sciences, Ulster University, Coleraine, UK
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2
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Abstract
INTRODUCTION : Obesity is recognised as a major healthcare challenge. Following years of slow progress in discovery of safe, effective therapies for weight management, recent approval of the glucagon-like peptide 1 receptor (GLP-1R) mimetics, liraglutide and semaglutide, for obesity has generated considerable excitement. It is anticipated these agents will pave the way for application of tirzepatide, a highly effective glucose-dependent insulinotropic polypeptide receptor (GIPR), GLP-1R co-agonist recently approved for management of type 2 diabetes mellitus. AREAS COVERED : Following promising weight loss in obese individuals in Phase III clinical trials, liraglutide and semaglutide were approved for weight management without diabetes. Tirzepatide has attained Fast Track designation for obesity management by the US Food and Drug Association. This narrative review summarises experimental, preclinical and clinical data for these agents and related GLP-1R/GIPR co-agonists, prioritising clinical research published within the last 10 years where possible. EXPERT OPINION : GLP-1R mimetics are often discontinued within 24-months, owing to gastrointestinal side-effects, meaning long-term application of these agents in obesity is questioned. Combined GIPR/GLP-1R agonism appears to induce fewer side-effects, indicating GLP-1R/GIPR co-agonists may be more suitable for enduring obesity management. After years of debate, this GIPR-biased GLP-1R/GIPR co-agonist highlights the therapeutic promise of including GIPR modulation for diabetes and obesity therapy.
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Affiliation(s)
- Ryan A Lafferty
- Diabetes Research Centre, Ulster University, Coleraine, Northern Ireland, BT52 1SA, UK
| | - Peter R Flatt
- Diabetes Research Centre, Ulster University, Coleraine, Northern Ireland, BT52 1SA, UK
| | - Nigel Irwin
- Diabetes Research Centre, Ulster University, Coleraine, Northern Ireland, BT52 1SA, UK
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McCloskey AG, Miskelly MG, Lafferty RA, Flatt PR, McKillop AM. Antidiabetic actions of GPR55 agonist Abn-CBD and sitagliptin in obese-diabetic high fat fed mice. Biochem Pharmacol 2023; 208:115398. [PMID: 36581052 DOI: 10.1016/j.bcp.2022.115398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 12/27/2022]
Abstract
GPR55 has been recognized as a novel anti-diabetic target exerting positive effects on beta cell function and mass. This study evaluated the metabolic actions and therapeutic efficacy of GPR55 agonist abnormal cannabidiol (Abn-CBD) administered alone and in combination with sitagliptin in diet-induced obese-diabetic mice. Chronic effects of 21-day oral administration of Abn-CBD (0.1 µmol/kg BW) monotherapy and in combination with sitagliptin (50 mg/kg BW) were assessed in obese-diabetic HFF mice (n = 8). Assessments of plasma glucose, circulating insulin, DPP-IV activity, CRP, amylase, lipids, body weight and food intake were undertaken. Glucose tolerance, insulin sensitivity, DEXA scanning and islet morphology analysis were performed at 21-days. Sitagliptin, Abn-CBD alone and in combination with sitagliptin attenuated plasma glucose by 37-53 % (p < 0.01 - p < 0.001) and enhanced circulating insulin concentrations by 23-31 % (p < 0.001). Abn-CBD alone and with sitagliptin reduced bodyweight by 9-10 % (p < 0.05). After 21-days, Abn-CBD in combination with sitagliptin (44 %; p < 0.01) improved glucose tolerance, whilst enhancing insulin sensitivity by 79 % (p < 0.01). Abn-CBD increased islet area (86 %; p < 0.05), beta cell mass (p < 0.05) and beta cell proliferation (164 %; p < 0.001), whilst in combination with sitagliptin islet area was decreased (50 %; p < 0.01). Abn-CBD alone, in combination with sitagliptin or sitagliptin alone decreased triglycerides by 34-65 % (p < 0.001) and total cholesterol concentrations by 15-25 % (p < 0.001). In addition, Abn-CBD in combination with sitagliptin reduced fat mass by 19 % (p < 0.05) and reduced CRP concentrations (39 %; p < 0.05). These findings advocate Abn-CBD monotherapy and in combination with sitagliptin as a novel and effective approach for bodyweight control and the treatment of glucose intolerance and dyslipidaemia in type-2-diabetes.
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Affiliation(s)
- Andrew G McCloskey
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, U.K; Health and Biomedical Research Centre (HEAL), Atlantic Technological University, ATU Sligo, Ash Lane, Sligo, F91 YW50, Ireland
| | - Michael G Miskelly
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, U.K
| | - Ryan A Lafferty
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, U.K
| | - Peter R Flatt
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, U.K
| | - Aine M McKillop
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, U.K.
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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] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 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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Lafferty RA, McShane LM, Franklin ZJ, Flatt PR, O’Harte FPM, Irwin N. Sustained glucagon receptor antagonism in insulin-deficient high-fat-fed mice. J Endocrinol 2022; 255:91-101. [PMID: 36005280 PMCID: PMC9513641 DOI: 10.1530/joe-22-0106] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022]
Abstract
Discerning modification to the amino acid sequence of native glucagon can generate specific glucagon receptor (GCGR) antagonists, that include desHis1Pro4Glu9-glucagon and the acylated form desHis1Pro4Glu9(Lys12PAL)-glucagon. In the current study, we have evaluated the metabolic benefits of once-daily injection of these peptide-based GCGR antagonists for 18 days in insulin-resistant high-fat-fed (HFF) mice with streptozotocin (STZ)-induced insulin deficiency, namely HFF-STZ mice. Administration of desHis1Pro4Glu9-glucagon moderately (P < 0.05) decreased STZ-induced elevations of food intake. Body weight was not different between groups of HFF-STZ mice and both treatment interventions delayed (P < 0.05) the onset of hyperglycaemia. The treatments reduced (P < 0.05-P < 0.001) circulating and pancreatic glucagon, whilst desHis1Pro4Glu9(Lys12PAL)-glucagon also substantially increased (P < 0.001) pancreatic insulin stores. Oral glucose tolerance was appreciably improved (P < 0.05) by both antagonists, despite the lack of augmentation of glucose-stimulated insulin release. Interestingly, positive effects on i.p. glucose tolerance were less obvious suggesting important beneficial effects on gut function. Metabolic benefits were accompanied by decreased (P < 0.05-P < 0.01) locomotor activity and increases (P < 0.001) in energy expenditure and respiratory exchange ratio in both treatment groups. In addition, desHis1Pro4Glu9-glucagon increased (P < 0.01-P < 0.001) O2 consumption and CO2 production. Together, these data provide further evidence that peptidic GCGR antagonists are effective treatment options for obesity-driven forms of diabetes, even when accompanied by insulin deficiency.
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Affiliation(s)
- Ryan A Lafferty
- Biomedical Sciences Research Institute, Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Laura M McShane
- Biomedical Sciences Research Institute, Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Zara J Franklin
- Biomedical Sciences Research Institute, Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- Biomedical Sciences Research Institute, Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Finbarr P M O’Harte
- Biomedical Sciences Research Institute, Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- Biomedical Sciences Research Institute, Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
- Correspondence should be addressed to N Irwin:
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Sarnobat D, Lafferty RA, Charlotte Moffett R, Tarasov AI, Flatt PR, Irwin N. Effects of artemether on pancreatic islet morphology, islet cell turnover and α-cell transdifferentiation in insulin-deficient GluCreERT2;ROSA26-eYFP diabetic mice. J Pharm Pharmacol 2022; 74:1758-1764. [PMID: 36206181 DOI: 10.1093/jpp/rgac075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 09/05/2022] [Indexed: 01/26/2023]
Abstract
OBJECTIVES The antimalarial drug artemether is suggested to effect pancreatic islet cell transdifferentiation, presumably through activation γ-aminobutyric acid receptors, but this biological action is contested. METHODS We have investigated changes in α-cell lineage in response to 10-days treatment with artemether (100 mg/kg oral, once daily) on a background of β-cell stress induced by multiple low-dose streptozotocin (STZ) injection in GluCreERT2; ROSA26-eYFP transgenic mice. KEY FINDINGS Artemether intervention did not affect the actions of STZ on body weight, food and fluid intake or blood glucose. Circulating insulin and glucagon were reduced by STZ treatment, with a corresponding decline in pancreatic insulin content, which were not altered by artemether. The detrimental changes to pancreatic islet morphology induced by STZ were also evident in artemether-treated mice. Tracing of α-cell lineage, through co-staining for glucagon and yellow fluorescent protein (YFP), revealed a significant decrease of the proportion of glucagon+YFP- cells in STZ-diabetic mice, which was reversed by artemether. However, artemether had no effect on transdifferentiation of α-cells into β-cells and failed to augment the number of bi-hormonal, insulin+glucagon+, islet cells. CONCLUSIONS Our observations confirm that artemisinin derivatives do not impart meaningful benefits on islet cell lineage transition events or pancreatic islet morphology.
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Affiliation(s)
- Dipak Sarnobat
- Biomedical Sciences Research Institute, Centre for Diabetes, Ulster University, Coleraine, UK
| | - Ryan A Lafferty
- Biomedical Sciences Research Institute, Centre for Diabetes, Ulster University, Coleraine, UK
| | - R Charlotte Moffett
- Biomedical Sciences Research Institute, Centre for Diabetes, Ulster University, Coleraine, UK
| | - Andrei I Tarasov
- Biomedical Sciences Research Institute, Centre for Diabetes, Ulster University, Coleraine, UK
| | - Peter R Flatt
- Biomedical Sciences Research Institute, Centre for Diabetes, Ulster University, Coleraine, UK
| | - Nigel Irwin
- Biomedical Sciences Research Institute, Centre for Diabetes, Ulster University, Coleraine, UK
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Mohan S, Lafferty RA, Flatt PR, Moffett RC, Irwin N. Ac3IV, a V1a and V1b receptor selective vasopressin analogue, protects against hydrocortisone-induced changes in pancreatic islet cell lineage. Peptides 2022; 152:170772. [PMID: 35202749 DOI: 10.1016/j.peptides.2022.170772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/11/2022] [Accepted: 02/17/2022] [Indexed: 11/25/2022]
Abstract
The Avpr1a (V1a) and Avpr1b (V1b) receptor selective, vasopressin (AVP) analogue, Ac3IV has been shown to improve metabolism and pancreatic islet structure in diabetes and insulin resistance. The present study further investigates these actions by assessing the ability of Ac3IV to protect against pancreatic islet architectural disturbances induced by hydrocortisone (HC) treatment in transgenic Ins1Cre/+;Rosa26-eYFP mice, that possess beta-cell lineage tracing capabilities. HC intervention increased (p < 0.001) energy intake but reduced (p < 0.01) body weight gain, with no impact of Ac3IV. All HC mice had reduced (p < 0.05) circulating glucose, but plasma insulin and glucagon concentrations remained unchanged. However, HC mice presented with increased (p < 0.001) pancreatic insulin content, which was further augmented by Ac3IV. In addition, Ac3IV treatment countered HC-induced increases in islet-, beta- and alpha-cell areas (p < 0.01), as well as promoting islet number towards control levels. This was accompanied by reduced (p < 0.05) beta-cell growth, but enhanced (p < 0.001) alpha-cell proliferation. There were no changes in islet cell apoptotic rates in any of the groups of HC mice, but co-expression of CK19 with insulin in pancreatic ductal cells was reduced by Ac3IV. Assessment of beta-cell lineage revealed that Ac3IV partially protected against HC-mediated de-differentiation of mature beta-cells, whilst also decreasing (p < 0.01) beta- to alpha-cell transdifferentiation. Our data indicate that sustained activation of V1a and V1b receptors exerts positive islet cell transition effects to help retain beta-cell identity in HC mice.
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Affiliation(s)
- Shruti Mohan
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Ryan A Lafferty
- 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
| | - 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.
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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] [What about the content of this article? (0)] [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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McLaughlin CM, Harnedy-Rothwell PA, Lafferty RA, Sharkey S, Parthsarathy V, Allsopp PJ, McSorley EM, FitzGerald RJ, O'Harte FPM. Macroalgal protein hydrolysates from Palmaria palmata influence the 'incretin effect' in vitro via DPP-4 inhibition and upregulation of insulin, GLP-1 and GIP secretion. Eur J Nutr 2021; 60:4439-4452. [PMID: 34081167 PMCID: PMC8572210 DOI: 10.1007/s00394-021-02583-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 05/11/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE This study investigated metabolic benefits of protein hydrolysates from the macroalgae Palmaria palmata, previously shown to inhibit dipeptidylpeptidase-4 (DPP-4) activity in vitro. METHODS Previously, Alcalase/Flavourzyme-produced P. palmata protein hydrolysate (PPPH) improved glycaemia and insulin production in streptozotocin-induced diabetic mice. Here the PPPH, was compared to alternative Alcalase, bromelain and Promod-derived hydrolysates and an unhydrolysed control. All PPPH's underwent simulated gastrointestinal digestion (SGID) to establish oral bioavailability. PPPH's and their SGID counterparts were tested in pancreatic, clonal BRIN-BD11 cells to assess their insulinotropic effect and associated intracellular mechanisms. PPPH actions on the incretin effect were assessed via measurement of DPP-4 activity, coupled with GLP-1 and GIP release from GLUTag and STC-1 cells, respectively. Acute in vivo effects of Alcalase/Flavourzyme PPPH administration on glucose tolerance and satiety were assessed in overnight-fasted mice. RESULTS PPPH's (0.02-2.5 mg/ml) elicited varying insulinotropic effects (p < 0.05-0.001). SGID of the unhydrolysed protein control, bromelain and Promod PPPH's retained, or improved, bioactivity regarding insulin secretion, DPP-4 inhibition and GIP release. Insulinotropic effects were retained for all SGID-hydrolysates at higher PPPH concentrations. DPP-4 inhibitory effects were confirmed for all PPPH's and SGID counterparts (p < 0.05-0.001). PPPH's were shown to directly influence the incretin effect via upregulated GLP-1 and GIP (p < 0.01-0.001) secretion in vitro, largely retained after SGID. Alcalase/Flavourzyme PPPH produced the greatest elevation in cAMP (p < 0.001, 1.7-fold), which was fully retained post-SGID. This hydrolysate elicited elevations in intracellular calcium (p < 0.01) and membrane potential (p < 0.001). In acute in vivo settings, Alcalase/Flavourzyme PPPH improved glucose tolerance (p < 0.01-0.001) and satiety (p < 0.05-0.001). CONCLUSION Bioavailable PPPH peptides may be useful for the management of T2DM and obesity.
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Affiliation(s)
- C M McLaughlin
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Co. Derry, BT52 1SA, Northern Ireland
| | - P A Harnedy-Rothwell
- Department of Biological Sciences, University of Limerick, Castletroy, Limerick, Ireland
- Health Research Institute (HRI), University of Limerick, Limerick, Ireland
| | - R A Lafferty
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Co. Derry, BT52 1SA, Northern Ireland
| | - S Sharkey
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Co. Derry, BT52 1SA, Northern Ireland
| | - V Parthsarathy
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Co. Derry, BT52 1SA, Northern Ireland
| | - P J Allsopp
- Nutrition Innovation Centre for Food and Health, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Co. Derry, BT52 1SA, Northern Ireland
| | - E M McSorley
- Nutrition Innovation Centre for Food and Health, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Co. Derry, BT52 1SA, Northern Ireland
| | - R J FitzGerald
- Department of Biological Sciences, University of Limerick, Castletroy, Limerick, Ireland
- Health Research Institute (HRI), University of Limerick, Limerick, Ireland
| | - F P M O'Harte
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Co. Derry, BT52 1SA, Northern Ireland.
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Abstract
Initially discovered as an impurity in insulin preparations, our understanding of the hyperglycaemic hormone glucagon has evolved markedly over subsequent decades. With description of the precursor proglucagon, we now appreciate that glucagon was just the first proglucagon-derived peptide (PGDP) to be characterised. Other bioactive members of the PGDP family include glucagon-like peptides -1 and -2 (GLP-1 and GLP-2), oxyntomodulin (OXM), glicentin and glicentin-related pancreatic peptide (GRPP), with these being produced via tissue-specific processing of proglucagon by the prohormone convertase (PC) enzymes, PC1/3 and PC2. PGDP peptides exert unique physiological effects that influence metabolism and energy regulation, which has witnessed several of them exploited in the form of long-acting, enzymatically resistant analogues for treatment of various pathologies. As such, intramuscular glucagon is well established in rescue of hypoglycaemia, while GLP-2 analogues are indicated in the management of short bowel syndrome. Furthermore, since approval of the first GLP-1 mimetic for the management of Type 2 diabetes mellitus (T2DM) in 2005, GLP-1 therapeutics have become a mainstay of T2DM management due to multifaceted and sustainable improvements in glycaemia, appetite control and weight loss. More recently, longer-acting PGDP therapeutics have been developed, while newfound benefits on cardioprotection, bone health, renal and liver function and cognition have been uncovered. In the present article, we discuss the physiology of PGDP peptides and their therapeutic applications, with a focus on successful design of analogues including dual and triple PGDP receptor agonists currently in clinical development.
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Affiliation(s)
| | | | | | - Victor A. Gault
- School of Biomedical Sciences, Ulster University, Coleraine, United Kingdom
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Abstract
PURPOSE OF REVIEW The antiobesity effects of activation of hypothalamic neuropeptide Y2 receptors (NPYR2) by the gut-derived hormone, peptide YY (PYY), are established. However, more recent insight into the biology of PYY has demonstrated remarkable benefits of sustained activation of pancreatic beta-cell NPYR1, that promises to open a new therapeutic avenue in diabetes. RECENT FINDINGS The therapeutic applicability of NPYR2 agonists for obesity has been considered for many years. An alternative pathway for the clinical realisation of PYY-based drugs could be related to the development of NPYR1 agonists for treatment of diabetes. Thus, although stimulation of NPYR1 on pancreatic beta-cells has immediate insulinostatic effects, prolonged activation of these receptors leads to well defined beta-cell protective effects, with obvious positive implications for the treatment of diabetes. In this regard, NPYR1-specific, long-acting enzyme resistant PYY analogues, have been recently developed with encouraging preclinical effects observed on pancreatic islet architecture in diabetes. In agreement, the benefits of certain types of bariatric surgeries on beta-cell function and responsiveness have also been linked to elevated PYY secretion and NPY1 receptor activation. SUMMARY Enzymatically stable forms of PYY, that selectively activate NPYR1, may have significant potential for preservation of beta-cell mass and the treatment of diabetes.
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Affiliation(s)
- Ryan A Lafferty
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK
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Lafferty RA, Tanday N, Moffett RC, Reimann F, Gribble FM, Flatt PR, Irwin N. Positive Effects of NPY1 Receptor Activation on Islet Structure Are Driven by Pancreatic Alpha- and Beta-Cell Transdifferentiation in Diabetic Mice. Front Endocrinol (Lausanne) 2021; 12:633625. [PMID: 33716983 PMCID: PMC7949013 DOI: 10.3389/fendo.2021.633625] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/20/2021] [Indexed: 02/03/2023] Open
Abstract
Enzymatically stable and specific neuropeptide Y1 receptor (NPYR1) agonists, such as sea lamprey PYY(1-36) (SL-PYY(1-36)), are believed to improve glucose regulation in diabetes by targeting pancreatic islets. In this study, streptozotocin (STZ) diabetic transgenic GluCreERT2 ;ROSA26-eYFP and Ins1Cre/+;Rosa26-eYFP mouse models have been used to study effects of sustained NPYR1 activation on islet cell composition and alpha- and beta-cell lineage transitioning. STZ induced a particularly severe form of diabetes in Ins1Cre/+;Rosa26-eYFP mice, but twice-daily administration (25 nmol/kg) of SL-PYY(1-36) for 11 days consistently improved metabolic status. Blood glucose was decreased (p < 0.05 - p < 0.001) and both fasted plasma and pancreatic insulin significantly increased by SL-PYY(1-36). In both GluCreERT2 ;ROSA26-eYFP and Ins1Cre/+; Rosa26-eYFP mice, STZ provoked characteristic losses (p < 0.05 - p < 0.001) of islet numbers, beta-cell and pancreatic islet areas together with increases in area and central islet location of alpha-cells. With exception of alpha-cell area, these morphological changes were fully, or partially, returned to non-diabetic control levels by SL-PYY(1-36). Interestingly, STZ apparently triggered decreased (p < 0.001) alpha- to beta-cell transition in GluCreERT2 ;ROSA26-eYFP mice, together with increased loss of beta-cell identity in Ins1Cre/+;Rosa26-eYFP mice, but both effects were significantly (p < 0.001) reversed by SL-PYY(1-36). SL-PYY(1-36) also apparently reduced (p < 0.05) beta- to alpha-cell conversion in Ins1Cre/+;Rosa26-eYFP mice and glucagon expressing alpha-cells in GluCreERT2 ;ROSA26-eYFP mice. These data indicate that islet benefits of prolonged NPY1R activation, and especially restoration of beta-cell mass, are observed irrespective of diabetes status, being linked to cell lineage alterations including transdifferentiation of alpha- to beta-cells.
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Affiliation(s)
- Ryan A. Lafferty
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, United Kingdom
| | - Neil Tanday
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, United Kingdom
| | - R. Charlotte Moffett
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, United Kingdom
| | - Frank Reimann
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Fiona M. Gribble
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Peter R. Flatt
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, United Kingdom
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, United Kingdom
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Tanday N, English A, Lafferty RA, Flatt PR, Irwin N. Benefits of Sustained Upregulated Unimolecular GLP-1 and CCK Receptor Signalling in Obesity-Diabetes. Front Endocrinol (Lausanne) 2021; 12:674704. [PMID: 34054734 PMCID: PMC8160446 DOI: 10.3389/fendo.2021.674704] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/29/2021] [Indexed: 12/11/2022] Open
Abstract
Combined activation of GLP-1 and CCK1 receptors has potential to synergistically augment the appetite-suppressive and glucose homeostatic actions of the individual parent peptides. In the current study, pancreatic beta-cell benefits of combined GLP-1 and CCK1 receptor upregulation were established, before characterising bioactivity and antidiabetic efficacy of an acylated dual-acting GLP-1/CCK hybrid peptide, namely [Lys12Pal]Ex-4/CCK. Both exendin-4 and CCK exhibited (p<0.001) proliferative and anti-apoptotic effects in BRIN BD11 beta-cells. Proliferative benefits were significantly (p<0.01) augmented by combined peptide treatment when compared to either parent peptide alone. These effects were linked to increases (p<0.001) in GLUT2 and glucokinase beta-cell gene expression, with decreased (p<0.05-p<0.001) expression of NFκB and BAX. [Lys12Pal]Ex-4/CCK exhibited prominent insulinotropic actions in vitro, coupled with beneficial (p<0.001) satiety and glucose homeostatic effects in the mice, with bioactivity evident 24 h after administration. Following twice daily injection of [Lys12Pal]Ex-4/CCK for 28 days in diabetic high fat fed (HFF) mice with streptozotocin (STZ)-induced compromised beta-cells, there were clear reductions (p<0.05-p<0.001) in energy intake and body weight. Circulating glucose was returned to lean control concentrations, with associated increases (p<0.001) in plasma and pancreatic insulin levels. Glucose tolerance and insulin secretory responsiveness were significantly (p<0.05-p<0.001) improved by hybrid peptide therapy. In keeping with this, evaluation of pancreatic histology revealed restoration of normal islet alpha- to beta-cell ratios and reduction (p<0.01) in centralised islet glucagon staining. Improvements in pancreatic islet morphology were associated with increased (p<0.05) proliferation and reduced (p<0.001) apoptosis of beta-cells. Together, these data highlight the effectiveness of sustained dual GLP-1 and CCK1 receptor activation by [Lys12Pal]Ex-4/CCK for the treatment of obesity-related diabetes.
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MESH Headings
- Animals
- Biomarkers/blood
- Blood Glucose/analysis
- Body Weight
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Diet, High-Fat
- Exenatide/pharmacology
- Glucagon-Like Peptide 1/genetics
- Glucagon-Like Peptide 1/metabolism
- Hypoglycemic Agents/pharmacology
- Insulin Secretion
- Insulin-Secreting Cells/drug effects
- Insulin-Secreting Cells/metabolism
- Insulin-Secreting Cells/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Obesity/physiopathology
- Peptide Fragments/pharmacology
- Receptors, Cholecystokinin/genetics
- Receptors, Cholecystokinin/metabolism
- Up-Regulation
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14
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Lafferty RA, Tanday N, Flatt PR, Irwin N. Generation and characterisation of C-terminally stabilised PYY molecules with potential in vivo NPYR2 activity. Metabolism 2020; 111:154339. [PMID: 32777442 DOI: 10.1016/j.metabol.2020.154339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/09/2020] [Accepted: 07/30/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Activation of neuropeptide Y2 receptors (NPYR2) by the N-terminally truncated, dipeptidyl peptidase-4 (DPP-4) generated, Peptide YY (PYY) metabolite, namely PYY(3-36), results in satiating actions. However, PYY(3-36) is also subject to C-terminal enzymatic cleavage, which annuls anorectic effects. METHODS Substitution of l-Arg35 with d-Arg35 in the DPP-4 stable sea lamprey PYY(1-36) peptide imparts full C-terminal stability. In the current study, we have taken this molecule and introduced DPP-4 susceptibility by Iso3 substitution. RESULTS As expected, [Iso3]sea lamprey PYY(1-36) and [Iso3](d-Arg35)sea lamprey PYY(1-36) were N-terminally degraded to respective PYY(3-36) metabolites in plasma. Only [Iso3](d-Arg35)sea lamprey PYY(1-36) was C-terminally stable. Both peptides possessed similar insulinostatic and anti-apoptotic biological actions to native PYY(1-36) in beta-cells. Unlike native PYY(1-36) and [Iso3](d-Arg35)sea lamprey PYY(1-36), [Iso3]sea lamprey PYY(1-36) displayed some proliferative actions in Npyr1 knockout beta-cells. In addition, [Iso3]sea lamprey PYY(1-36) induced more rapid NPYR2-dependent appetite suppressive effects in mice than its C-terminally stable counterpart. Twice daily administration of either peptide to high fat fed (HFF) mice resulted in significant body weight reduction and improvements in circulating triglyceride levels. [Iso3]sea lamprey PYY(1-36) treatment also prevented elevations in glucagon. Both peptides, and especially [Iso3]sea lamprey PYY(1-36), improved glucose tolerance. The treatment interventions also partially reversed the deleterious effects of sustained high fat feeding on pancreatic islet morphology. CONCLUSION The present study confirms that sustained NPYR2 receptor activation by [Iso3](d-Arg35)sea lamprey induced significant weight lowering actions. However, identifiable benefits of this peptide over [Iso3]sea lamprey PYY(1-36), which was not protected against C-terminal degradation, were not pronounced.
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Affiliation(s)
- Ryan A Lafferty
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland BT52 1SA, UK
| | - Neil Tanday
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland BT52 1SA, UK
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland BT52 1SA, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland BT52 1SA, UK.
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15
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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] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2019] [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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16
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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. Clin Med Insights Endocrinol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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17
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Abstract
The vast majority of research to date on the gut hormone Peptide YY (PYY) has focused on appetite suppression and body weight regulation effects. These biological actions are believed to occur through interaction of PYY with hypothalamic Y2 receptors. However, more recent studies have added additional knowledge to understanding of the physiological, and potential therapeutic, roles of PYY beyond obesity alone. Thus, PYY has now been shown to impart improvements in pancreatic beta-cell survival and function, with obvious benefits for diabetes. This effect has been linked mainly to binding and activation of Y1 receptors by PYY, but more evidence is still required in this regard. Given the potential therapeutic promise of PYY-derived compounds, and complexity of receptor interactions, it is important to fully understand the complete biological action profile of PYY. Therefore, the current review aims to compile, evaluate and summarise current knowledge on PYY, with particular emphasis on obesity and diabetes treatment, and the importance of specific Y receptor interactions for this.
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Affiliation(s)
- Ryan A Lafferty
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, UK
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, UK.
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19
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Megaw J, Thompson TP, Lafferty RA, Gilmore BF. Galleria mellonella as a novel in vivo model for assessment of the toxicity of 1-alkyl-3-methylimidazolium chloride ionic liquids. Chemosphere 2015; 139:197-201. [PMID: 26121605 DOI: 10.1016/j.chemosphere.2015.06.026] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 05/12/2015] [Accepted: 06/05/2015] [Indexed: 06/04/2023]
Abstract
The larval form of the Greater Wax Moth (Galleria mellonella) was evaluated as a model system for the study of the acute in vivo toxicity of 1-alkyl-3-methylimidazolium chloride ionic liquids. 24-h median lethal dose (LD50) values for nine of these ionic liquids bearing alkyl chain substituents ranging from 2 to 18 carbon atoms were determined. The in vivo toxicity of the ionic liquids was found to correlate directly with the length of the alkyl chain substituent, and the pattern of toxicity observed was in accordance with previous studies of ionic liquid toxicity in other living systems, including a characteristic toxicity 'cut-off' effect. However, G. mellonella appeared to be more susceptible to the toxic effects of the ionic liquids tested, possibly as a result of their high body fat content. The results obtained in this study indicate that G. mellonella represents a sensitive, reliable and robust in vivo model organism for the evaluation of ionic liquid toxicity.
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Affiliation(s)
- Julianne Megaw
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK.
| | - Thomas P Thompson
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK.
| | - Ryan A Lafferty
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK.
| | - Brendan F Gilmore
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK.
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