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Kaur M, Misra S. A review of an investigational drug retatrutide, a novel triple agonist agent for the treatment of obesity. Eur J Clin Pharmacol 2024; 80:669-676. [PMID: 38367045 DOI: 10.1007/s00228-024-03646-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 02/02/2024] [Indexed: 02/19/2024]
Abstract
BACKGROUND Obesity is one of the critical public health problems in our society. It leads to various health conditions, such as type 2 diabetes mellitus, cardiovascular disease, hypertension, dyslipidaemia, and non-alcoholic fatty liver disease. With the rising incidence of obesity, there is a growing demand for new therapies which can effectively manage body weight and improve health. CURRENT EVIDENCE Currently under development, multi-receptor agonist drugs may offer a promising solution to meet this unmet medical need. Retatrutide is a novel triple receptor agonist peptide that targets the glucagon receptor (GCGR), glucose-dependent insulinotropic polypeptide receptor (GIPR), and glucagon-like peptide-1 receptor (GLP-1R). This novel drug has the potential to treat metabolic abnormalities associated with obesity as well as diseases resulting from it due to its distinct mechanism of action. The Phase III trial of this pipeline drug for treating type 2 diabetes mellitus, non-alcoholic fatty liver disease, and obesity started on August 28, 2023. The results of a Phase II clinical trial have demonstrated significant weight reduction in overweight and obese adults. Specifically, the trial reported an average weight loss of 17.5% and 24.4% at 24 and 48 weeks, respectively. CONCLUSIONS These findings hold promise for the development of effective weight loss interventions in this population group. There is a need for more phase III studies to provide sufficient clinical evidence for the effectiveness of retatrutide, as current evidence is limited to phase II studies and has yet to prove its worth in a larger population. Here, we aimed to provide an overview of retatrutide's safety and effectiveness in treating obesity.
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Affiliation(s)
- Manmeet Kaur
- Department of Pharmacology, Kalpana Chawla Government Medical College, Karnal, India
| | - Saurav Misra
- Department of Pharmacology, Kalpana Chawla Government Medical College, Karnal, India.
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Mangliar IA, Plante AS, Chabot M, Savard C, Lemieux S, Michaud A, Weisnagel SJ, Camirand Lemyre F, Veilleux A, Morisset AS. GLP-1 response during pregnancy: variations between trimesters and associations with appetite sensations and usual energy intake. Appl Physiol Nutr Metab 2024; 49:428-436. [PMID: 38095168 DOI: 10.1139/apnm-2023-0301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Further research is required to understand hormonal regulation of food intake during pregnancy and its association with energy intake. The objectives are to (i) compare postprandial responses of plasma glucagon-like peptide-1 (GLP-1) between trimesters, (ii) compare postprandial appetite sensations between trimesters, and (iii) examine trimester-specific associations between GLP-1 levels, appetite sensations, and usual energy intake. At each trimester, participants (n = 26) consumed a standard test meal following a 12 h fast. Plasma GLP-1 levels were measured by enzyme-linked immunosorbent assay method at fasting and at 30, 60, 120, and 180 min postprandial. A visual analogue scale assessing appetite sensations was completed at fasting and at 15, 30, 45, 60, 90, 120, 150, and 180 min postprandial. Mean energy intake was assessed using three web-based 24 h dietary recalls at each trimester. Lower postprandial GLP-1 responses were observed in the 2nd (p = 0.004) and 3rd trimesters (p < 0.001) compared to the 1st trimester. Greater postprandial sensations of desire to eat, hunger, and prospective food consumption were noted in the 3rd trimester compared to the 1st trimester (p < 0.04, for all). Fasting GLP-1 was negatively associated with fasting appetite sensations (except fullness) at the 2nd trimester (p < 0.02, for all). Postprandially, significant associations were observed for incremental areas under the curve from 0 to 30 min between GLP-1 and fullness at the 2nd (p = 0.01) and 3rd trimesters (p = 0.03). No associations between fasting or postprandial GLP-1 and usual energy intake were observed. Overall, GLP-1 and appetite sensation responses significantly differ between trimesters, but few associations were observed between GLP-1, appetite sensations, and usual energy intake.
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Affiliation(s)
- Inès Auclair Mangliar
- School of Nutrition, Université Laval, Québec, QC, Canada
- Nutrition, Health and Society (NUTRISS) Research Centre, Institute of Nutrition and Functional Foods (INAF), Université Laval, Québec, QC, Canada
- Endocrinology and Nephrology Unit, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
| | - Anne-Sophie Plante
- Nutrition, Health and Society (NUTRISS) Research Centre, Institute of Nutrition and Functional Foods (INAF), Université Laval, Québec, QC, Canada
- Endocrinology and Nephrology Unit, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
| | - Myriam Chabot
- Mathematics Department, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Claudia Savard
- School of Nutrition, Université Laval, Québec, QC, Canada
- Nutrition, Health and Society (NUTRISS) Research Centre, Institute of Nutrition and Functional Foods (INAF), Université Laval, Québec, QC, Canada
- Endocrinology and Nephrology Unit, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
| | - Simone Lemieux
- School of Nutrition, Université Laval, Québec, QC, Canada
- Nutrition, Health and Society (NUTRISS) Research Centre, Institute of Nutrition and Functional Foods (INAF), Université Laval, Québec, QC, Canada
| | - Andréanne Michaud
- School of Nutrition, Université Laval, Québec, QC, Canada
- Nutrition, Health and Society (NUTRISS) Research Centre, Institute of Nutrition and Functional Foods (INAF), Université Laval, Québec, QC, Canada
- Quebec Heart and Lung Institute, Université Laval, Québec, QC, Canada
| | - S John Weisnagel
- Endocrinology and Nephrology Unit, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
- Faculty of Medecine, Université Laval, Québec, QC, Canada
| | - Félix Camirand Lemyre
- Mathematics Department, Université de Sherbrooke, Sherbrooke, QC, Canada
- Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Alain Veilleux
- School of Nutrition, Université Laval, Québec, QC, Canada
- Nutrition, Health and Society (NUTRISS) Research Centre, Institute of Nutrition and Functional Foods (INAF), Université Laval, Québec, QC, Canada
| | - Anne-Sophie Morisset
- School of Nutrition, Université Laval, Québec, QC, Canada
- Nutrition, Health and Society (NUTRISS) Research Centre, Institute of Nutrition and Functional Foods (INAF), Université Laval, Québec, QC, Canada
- Endocrinology and Nephrology Unit, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
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Tanday N, Coulter-Parkhill A, Moffett RC, Suruli K, Dubey V, Flatt PR, Irwin N. Sex-based impact of pancreatic islet stressors in GluCreERT2/Rosa26-eYFP mice. J Endocrinol 2023; 259:e230174. [PMID: 37650517 PMCID: PMC10563506 DOI: 10.1530/joe-23-0174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/29/2023] [Indexed: 09/01/2023]
Abstract
The present study examines differences in metabolic and pancreatic islet adaptative responses following streptozotocin (STZ) and hydrocortisone (HC) administration in male and female transgenic GluCreERT2/Rosa26-eYFP mice. Mice received five daily doses of STZ (50 mg/kg, i.p.) or 10 daily doses of HC (70 mg/kg, i.p.), with parameters assessed on day 11. STZ-induced hyperglycaemia was evident in both sexes, alongside impaired glucose tolerance and reduced insulin concentrations. HC also had similar metabolic effects in male and female mice resulting in classical increases of circulating insulin indicative of insulin resistance. Control male mice had larger pancreatic islets than females and displayed a greater reduction of islet and beta-cell area in response to STZ insult. In addition, female STZ mice had lower levels of beta-cell apoptosis than male counterparts. Following HC administration, female mouse islets contained a greater proportion of alpha cells when compared to males. All HC mice presented with relatively comparable increases in beta- and alpha-cell turnover rates, with female mice being slightly more susceptible to HC-induced beta-cell apoptosis. Interestingly, healthy control female mice had inherently increased alpha-to-beta-cell transdifferentiation rates, which was decreased by HC treatment. The number of glucagon-positive alpha cells altering their lineage to insulin-positive beta cells was increased in male, but not female, STZ mice. Taken together, although there was no obvious sex-specific alteration of metabolic profile in STZ or HC mice, subtle differences in pancreatic islet morphology emphasises the impact of sex hormones on islets and importance of taking care when interpreting observations between males and females.
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Affiliation(s)
- Neil Tanday
- Diabetes Research Centre, Ulster University, Coleraine, Londonderry, Northern Ireland
| | | | - R Charlotte Moffett
- Diabetes Research Centre, Ulster University, Coleraine, Londonderry, Northern Ireland
| | - Karthick Suruli
- Diabetes Research Centre, Ulster University, Coleraine, Londonderry, Northern Ireland
| | - Vaibhav Dubey
- Diabetes Research Centre, Ulster University, Coleraine, Londonderry, Northern Ireland
| | - Peter R Flatt
- Diabetes Research Centre, Ulster University, Coleraine, Londonderry, Northern Ireland
| | - Nigel Irwin
- Diabetes Research Centre, Ulster University, Coleraine, Londonderry, Northern Ireland
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Sridhar A, Khan D, Flatt PR, Moffett CR, Irwin N. GLP-1 receptor agonism and GIP receptor antagonism induce substantial alterations in enteroendocrine and islet cell populations in obese high fat fed mice. Peptides 2023; 169:171093. [PMID: 37660881 DOI: 10.1016/j.peptides.2023.171093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/21/2023] [Accepted: 08/30/2023] [Indexed: 09/05/2023]
Abstract
Effects of sustained activation of glucagon-like peptide-1 (GLP-1) receptors (GLP-1R) as well as antagonism of receptors for glucose-dependent insulinotropic peptide (GIP) on intestinal morphology and related gut hormone populations have not been fully investigated. The present study assesses the impact of 21-days twice daily treatment with the GLP-1R agonist exendin-4 (Ex-4), or the GIP receptor (GIPR) antagonist mGIP(3-30), on these features in obese mice fed a high fat diet (HFD). HFD mice presented with reduced crypt depth when compared to normal diet (ND) controls, which was reversed by Ex-4 treatment. Both regimens lead to an enlargement of villi length in HFD mice. HFD mice had increased numbers of GIP and PYY positive ileal cells, with both treatment interventions reversing the effect on PYY positive cells, but only Ex-4 restoring GIP ileal cell populations to ND levels. Ex-4 and mGIP (3-30) marginally decreased GLP-1 villi immunoreactivity and countered the reduction of ileal GLP-1 content caused by HFD. As expected, HFD mice presented with elevated pancreatic islet area. Interestingly, mGIP(3-30), but not Ex-4, enhanced islet and beta-cell areas in HFD mice despite lack of effect of beta-cell turnover, whilst Ex-4 increased delta-cell area. Co-localisation of islet PYY or GLP-1 with glucagon was increased by Ex-4, whilst islet PYY co-immunoreactivity with somatostatin was enhanced by mGIP(3-30) treatment. These observations highlight potential new mechanisms linked to the metabolic benefits of GLP-1R agonism and GIPR antagonism in obesity.
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Affiliation(s)
- Ananyaa Sridhar
- Diabetes Research Centre, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, UK
| | - Dawood Khan
- Diabetes Research Centre, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- Diabetes Research Centre, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, UK
| | - Charlotte R Moffett
- Diabetes Research Centre, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- Diabetes Research Centre, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, UK.
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Jagomäe T, Gaur N, Seppa K, Reimets R, Pastak M, Plaas M, Kaasik A, Vasar E, Plaas M. Treatment with the dual-incretin agonist DA-CH5 demonstrates potent therapeutic effect in a rat model of Wolfram Syndrome. Front Endocrinol (Lausanne) 2023; 14:1234925. [PMID: 37900147 PMCID: PMC10611518 DOI: 10.3389/fendo.2023.1234925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 09/27/2023] [Indexed: 10/31/2023] Open
Abstract
Aim Wolfram Syndrome (WS) is a rare condition caused by mutations in Wfs1, with a poor prognosis and no cure. Mono-agonists targeting the incretin glucagon-like-peptide 1 (GLP-1) have demonstrated disease-modifying potential in pre-clinical and clinical settings. Dual agonists that target GLP-1 and glucose-dependent insulinotropic polypeptide (GIP-1) are reportedly more efficacious; hence, we evaluated the therapeutic potential of dual incretin agonism in a loss-of-function rat model of WS. Methods Eight-month-old Wfs1 knock-out (KO) and wild-type control rats were continuously treated with either the dual agonist DA-CH5 or saline for four months. Glycemic profile, visual acuity and hearing sensitivity were longitudinally monitored pre-treatment, and then at 10.5 and 12 months. Pancreata and retina were harvested for immunohistological analysis. Results DA-CH5 therapy reversed glucose intolerance in KO rats and provided lasting anti-diabetogenic protection. Treatment also reversed intra-islet alterations, including reduced endocrine islet area and β-cell density, indicating its regenerative potential. Although no rescue effect was noted for hearing loss, visual acuity and retinal ganglion cell density were better preserved in DA-CH5-treated rats. Conclusion We present preclinical evidence for the pleiotropic therapeutic effects of long-term dual incretin agonist treatment; effects were seen despite treatment beginning after symptom-onset, indicating reversal of disease progression. Dual incretins represent a promising therapeutic avenue for WS patients.
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Affiliation(s)
- Toomas Jagomäe
- Laboratory Animal Centre, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
| | - Nayana Gaur
- Laboratory Animal Centre, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
| | - Kadri Seppa
- Laboratory Animal Centre, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
| | - Riin Reimets
- Laboratory Animal Centre, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
| | - Marko Pastak
- Eye Clinic of Tartu University Hospital, Tartu, Estonia
| | - Mihkel Plaas
- Ear Clinic of Tartu University Hospital, Tartu, Estonia
| | - Allen Kaasik
- Department of Pharmacology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
| | - Eero Vasar
- Department of Physiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
| | - Mario Plaas
- Laboratory Animal Centre, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
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Lafferty RA, Flatt PR, Irwin N. GLP-1/GIP analogues: potential impact in the landscape of obesity pharmacotherapy. Expert Opin Pharmacother 2023; 24:587-597. [PMID: 36927378 DOI: 10.1080/14656566.2023.2192865] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
INTRODUCTION : Obesity is recognised as a major healthcare challenge. Following years of slow progress in discovery of safe, effective therapies for weight management, recent approval of the glucagon-like peptide 1 receptor (GLP-1R) mimetics, liraglutide and semaglutide, for obesity has generated considerable excitement. It is anticipated these agents will pave the way for application of tirzepatide, a highly effective glucose-dependent insulinotropic polypeptide receptor (GIPR), GLP-1R co-agonist recently approved for management of type 2 diabetes mellitus. AREAS COVERED : Following promising weight loss in obese individuals in Phase III clinical trials, liraglutide and semaglutide were approved for weight management without diabetes. Tirzepatide has attained Fast Track designation for obesity management by the US Food and Drug Association. This narrative review summarises experimental, preclinical and clinical data for these agents and related GLP-1R/GIPR co-agonists, prioritising clinical research published within the last 10 years where possible. EXPERT OPINION : GLP-1R mimetics are often discontinued within 24-months, owing to gastrointestinal side-effects, meaning long-term application of these agents in obesity is questioned. Combined GIPR/GLP-1R agonism appears to induce fewer side-effects, indicating GLP-1R/GIPR co-agonists may be more suitable for enduring obesity management. After years of debate, this GIPR-biased GLP-1R/GIPR co-agonist highlights the therapeutic promise of including GIPR modulation for diabetes and obesity therapy.
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Affiliation(s)
- Ryan A Lafferty
- Diabetes Research Centre, Ulster University, Coleraine, Northern Ireland, BT52 1SA, UK
| | - Peter R Flatt
- Diabetes Research Centre, Ulster University, Coleraine, Northern Ireland, BT52 1SA, UK
| | - Nigel Irwin
- Diabetes Research Centre, Ulster University, Coleraine, Northern Ireland, BT52 1SA, UK
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Sridhar A, Khan D, Flatt PR, Irwin N, Moffett RC. PYY (3-36) protects against high fat feeding induced changes of pancreatic islet and intestinal hormone content and morphometry. Biochim Biophys Acta Gen Subj 2023; 1867:130359. [PMID: 37001706 DOI: 10.1016/j.bbagen.2023.130359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/16/2023] [Accepted: 03/23/2023] [Indexed: 03/31/2023]
Abstract
BACKGROUND Prolonged high fat feeding negatively impacts pancreatic and intestinal morphology. In this regard, direct effects of PYY(3-36) on intestinal cell and pancreatic islet morphometry are yet to be fully explored in the setting of obesity. METHODS We examined the influence of 21-days twice daily treatment with PYY(3-36) on these parameters in mice fed a high fat diet (HFD). RESULTS PYY(3-36) treatment decreased food intake, body weight and circulating glucose in HFD mice. In terms of intestinal morphology, crypt depth was restored to control levels by PYY(3-36), with an additional enlargement of villi length. PYY(3-36) also reversed HFD-induced decreases of ileal PYY, and especially GLP-1, content. HFD increased numbers of PYY and GIP positive ileal cells, with PYY(3-36) fully reversing the effect on PYY cell detection. There were no obvious differences in the overall number of GLP-1 positive ileal cells in all mice, barring PYY(3-36) marginally decreasing GLP-1 villi cell immunoreactivity. Within pancreatic islets, PYY(3-36) significantly decreased alpha-cell area, whilst islet, beta-, PYY- and delta-cell areas remained unchanged. However, PYY(3-36) increased the percentage of beta-cells while also reducing percentage alpha-cell area. This was related to PYY(3-36)-induced reductions of beta-cell proliferation and apoptosis frequencies. Co-localisation of islet PYY with glucagon or somatostatin was elevated by PYY(3-36), with GLP-1/glucagon co-visualisation increased when compared to lean controls. CONCLUSION PYY(3-36) exerts protective effects on pancreatic and intestinal morphology in HFD mice linked to elevated ileal GLP-1 content. GENERAL SIGNIFICANCE These observations highlight mechanisms linked to the metabolic and weight reducing benefits of PYY(3-36).
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Affiliation(s)
- A Sridhar
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, N. Ireland, UK
| | - D Khan
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, N. Ireland, UK
| | - P R Flatt
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, N. Ireland, UK
| | - N Irwin
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, N. Ireland, UK.
| | - R C Moffett
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, N. Ireland, UK
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Sarnobat D, Moffett RC, Ma J, Flatt PR, McClenaghan NH, Tarasov AI. Taurine rescues pancreatic β-cell stress by stimulating α-cell transdifferentiation. Biofactors 2023. [PMID: 36714992 DOI: 10.1002/biof.1938] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 01/05/2023] [Indexed: 01/31/2023]
Abstract
The semi-essential ubiquitous amino acid taurine has been shown to alleviate obesity and hyperglycemia in humans; however, the pathways underlying the antidiabetic actions have not been characterized. We explored the effect of chronic taurine exposure on cell biology of pancreatic islets, in degenerative type 1-like diabetes. The latter was modeled by small dose of streptozotocin (STZ) injection for 5 days in mice, followed by a 10-day administration of taurine (2% w/v, orally) in the drinking water. Taurine treatment opposed the detrimental changes in islet morphology and β-/α-cell ratio, induced by STZ diabetes, coincidentally with a significant 3.9 ± 0.7-fold enhancement of proliferation and 40 ± 5% reduction of apoptosis in β-cells. In line with these findings, the treatment counteracted an upregulation of antioxidant (Sod1, Sod2, Cat, Gpx1) and downregulation of islet expansion (Ngn3, Itgb1) genes induced by STZ, in a pancreatic β-cell line. At the same time, taurine enhanced the transdifferentiation of α-cells into β-cells by 2.3 ± 0.8-fold, echoed in strong non-metabolic elevation of cytosolic Ca2+ levels in pancreatic α-cells. Our data suggest a bimodal effect of dietary taurine on islet β-cell biology, which combines the augmentation of α-/β-cell transdifferentiation with downregulation of apoptosis. The dualism of action, stemming presumably from the intra- and extracellular modality of the signal, is likely to explain the antidiabetic potential of taurine supplementation.
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Affiliation(s)
- Dipak Sarnobat
- School of Biomedical Sciences, Ulster University, Coleraine, UK
| | | | - Jinfang Ma
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Peter R Flatt
- School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - Neville H McClenaghan
- School of Biomedical Sciences, Ulster University, Coleraine, UK
- Department of Life Sciences, Atlantic Technological University, Sligo, Ireland
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Sridhar A, Khan D, Abdelaal M, Elliott JA, Naughton V, Flatt PR, Le Roux CW, Docherty NG, Moffett CR. Differential effects of RYGB surgery and best medical treatment for obesity-diabetes on intestinal and islet adaptations in obese-diabetic ZDSD rats. PLoS One 2022; 17:e0274788. [PMID: 36137097 PMCID: PMC9499270 DOI: 10.1371/journal.pone.0274788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 09/05/2022] [Indexed: 11/19/2022] Open
Abstract
Modification of gut-islet secretions after Roux-En-Y gastric bypass (RYBG) surgery contributes to its metabolic and anti-diabetic benefits. However, there is limited knowledge on tissue-specific hormone distribution post-RYGB surgery and how this compares with best medical treatment (BMT). In the present study, pancreatic and ileal tissues were excised from male Zucker-Diabetic Sprague Dawley (ZDSD) rats 8-weeks after RYGB, BMT (daily oral dosing with metformin 300mg/kg, fenofibrate 100mg/kg, ramipril 1mg/kg, rosuvastatin 10mg/kg and subcutaneous liraglutide 0.2mg/kg) or sham operation (laparotomy). Insulin, glucagon, somatostatin, PYY, GLP-1 and GIP expression patterns were assessed using immunocytochemistry and analyzed using ImageJ. After RYGB and BMT, body weight and plasma glucose were decreased. Intestinal morphometry was unaltered by RYGB, but crypt depth was decreased by BMT. Intestinal PYY cells were increased by both interventions. GLP-1- and GIP-cell counts were unchanged by RYGB but BMT increased ileal GLP-1-cells and decreased those expressing GIP. The intestinal contents of PYY and GLP-1 were significantly enhanced by RYGB, whereas BMT decreased ileal GLP-1. No changes of islet and beta-cell area or proliferation were observed, but the extent of beta-cell apoptosis and islet integrity calculated using circularity index were improved by both treatments. Significantly decreased islet alpha-cell areas were observed in both groups, while beta- and PYY-cell areas were unchanged. RYGB also induced a decrease in islet delta-cell area. PYY and GLP-1 colocalization with glucagon in islets was significantly decreased in both groups, while co-staining of PYY with glucagon was decreased and that with somatostatin increased. These data characterize significant cellular islet and intestinal adaptations following RYGB and BMT associated with amelioration of obesity-diabetes in ZDSD rats. The differential responses observed and particularly those within islets, may provide important clues to the unique ability of RYGB to cause diabetes remission.
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Affiliation(s)
- Ananyaa Sridhar
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Dawood Khan
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, United Kingdom
- * E-mail:
| | - Mahmoud Abdelaal
- Diabetes Complications Research Centre, School of Medicine, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Jessie A. Elliott
- Department of Surgery, Trinity Centre for Health Sciences and St. James’s Hospital, Dublin, Ireland
| | - Violetta Naughton
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Peter R. Flatt
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Carel W. Le Roux
- Diabetes Complications Research Centre, School of Medicine, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Neil G. Docherty
- Diabetes Complications Research Centre, School of Medicine, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Charlotte R. Moffett
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, United Kingdom
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Luo ZC, Jin ZR, Jiang YF, Wei TJ, Cao YL, Zhang Z, Wei R, Jiang H. The protective effects and underlying mechanisms of dapagliflozin on diabetes-induced testicular dysfunction. Asian J Androl 2022; 25:331-338. [PMID: 35848706 DOI: 10.4103/aja202242] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Male diabetic individuals present a marked impairment in fertility; however, knowledge regarding the pathogenic mechanisms and therapeutic strategies is unsatisfactory. The new hypoglycemic drug dapagliflozin has shown certain benefits, such as decreasing the risk of cardiovascular and renal events in patients with diabetes. Even so, until now, the effects and underlying mechanisms of dapagliflozin on diabetic male infertility have awaited clarification. Here, we found that dapagliflozin lowered blood glucose levels, alleviated seminiferous tubule destruction, and increased sperm concentrations and motility in leptin receptor-deficient diabetic db/db mice. Moreover, the glucagon-like peptide-1 receptor (GLP-1R) antagonist exendin (9-39) had no effect on glucose levels but reversed the protective effects of dapagliflozin on testicular structure and sperm quality in db/db mice. We also found that dapagliflozin inhibited the testicular apoptotic process by upregulating the expression of the antiapoptotic protein B-cell lymphoma 2 (BCL2) and X-linked inhibitor of apoptosis protein (XIAP) and inhibiting oxidative stress by enhancing the antioxidant status, including total antioxidant capacity, total superoxide dismutase (SOD) activity, and glutathione peroxidase (GPx) activity, as well as decreasing the level of 4-hydroxynonenal (4-HNE). Exendin (9-39) administration partially reversed these effects. Furthermore, dapagliflozin upregulated the glucagon-like peptide-1 (GLP-1) level in plasma and GLP-1R expression by promoting AKT8 virus oncogene cellular homolog (Akt) phosphorylation in testicular tissue. Exendin (9-39) partially inhibited Akt phosphorylation. These results suggest that dapagliflozin protects against diabetes-induced spermatogenic dysfunction via activation of the GLP-1R/phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. Our results indicate the potential effects of dapagliflozin against diabetes-induced spermatogenic dysfunction.
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Affiliation(s)
- Zhi-Chao Luo
- Department of Urology, Peking University Third Hospital, Beijing 100191, China
| | - Zi-Run Jin
- Department of Urology, Peking University Third Hospital, Beijing 100191, China
| | - Ya-Fei Jiang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Tian-Jiao Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Ya-Lei Cao
- Department of Urology, Peking University Third Hospital, Beijing 100191, China
| | - Zhe Zhang
- Department of Urology, Peking University Third Hospital, Beijing 100191, China.,Department of Reproductive Medicine Center, Peking University Third Hospital, Beijing 100191, China
| | - Rui Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Hui Jiang
- Department of Urology, Peking University Third Hospital, Beijing 100191, China.,Department of Reproductive Medicine Center, Peking University Third Hospital, Beijing 100191, China
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11
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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] [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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12
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Seino Y, Yamazaki Y. Roles of Glucose-Dependent Insulinotropic Polypeptide in Diet-Induced Obesity. J Diabetes Investig 2022; 13:1122-1128. [PMID: 35452190 PMCID: PMC9248429 DOI: 10.1111/jdi.13816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/08/2022] [Accepted: 04/18/2022] [Indexed: 11/28/2022] Open
Abstract
Glucose‐dependent insulinotropic polypeptide (GIP) and glucagon‐like peptide‐1 (GLP‐1) are incretins that play an important role in glucose metabolism, by increasing glucose‐induced insulin secretion from pancreatic β‐cells and help regulate bodyweight. Although they show a similar action on glucose‐induced insulin secretion, two incretins are distinct in various aspects. GIP is secreted from enteroendocrine K cell mainly expressed in the upper small intestine, and GLP‐1 is secreted from enteroendocrine L cells mainly expressed in the lower small intestine and colon by the stimulation of various nutrients. The mechanism of GIP secretion induced by nutrients, especially carbohydrates, is different from that of GLP‐1 secretion. GIP promotes fat deposition in adipose tissue, and contributes to fat‐induced obesity. In contrast, GLP‐1 participates in reducing bodyweight by suppressing food consumption and/or slowing gastric emptying. There is substantial evidence that GIP and GLP‐1 might differently contribute to bodyweight control. Although meal contents influence both glycemic and weight control, we do not fully understand whether incretin actions differ depending on the contents of the meal and what kind of signaling is involved in its context. We focus on the molecular mechanism of GIP secretion induced by nutrients, as well as the roles of GIP in weight changes caused by various diets.
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Affiliation(s)
- Yusuke Seino
- Department of Endocrinology, Diabetes and Metabolism, Fujita Health University, Toyoake, Japan
| | - Yuji Yamazaki
- Yutaka Seino Distinguished Center for Diabetes Research, Kansai Electric Power Medical Research Institute, Kobe, Japan.,Center for Diabetes, Endocrinology and Metabolism, Kansai Electric Power Hospital, Osaka, Japan
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13
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Khan D, Moffett RC, Flatt PR, Tarasov AI. Classical and non-classical islet peptides in the control of β-cell function. Peptides 2022; 150:170715. [PMID: 34958851 DOI: 10.1016/j.peptides.2021.170715] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/25/2021] [Accepted: 12/17/2021] [Indexed: 12/25/2022]
Abstract
The dual role of the pancreas as both an endocrine and exocrine gland is vital for food digestion and control of nutrient metabolism. The exocrine pancreas secretes enzymes into the small intestine aiding digestion of sugars and fats, whereas the endocrine pancreas secretes a cocktail of hormones into the blood, which is responsible for blood glucose control and regulation of carbohydrate, protein and fat metabolism. Classical islet hormones, insulin, glucagon, pancreatic polypeptide and somatostatin, interact in an autocrine and paracrine manner, to fine-tube the islet function and insulin secretion to the needs of the body. Recently pancreatic islets have been reported to express a number of non-classical peptide hormones involved in metabolic signalling, whose major production site was believed to reside outside pancreas, e.g. in the small intestine. We highlight the key non-classical islet peptides, and consider their involvement, together with established islet hormones, in regulation of stimulus-secretion coupling as well as proliferation, survival and transdifferentiation of β-cells. We furthermore focus on the paracrine interaction between classical and non-classical islet hormones in the maintenance of β-cell function. Understanding the functional relationships between these islet peptides might help to develop novel, more efficient treatments for diabetes and related metabolic disorders.
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Affiliation(s)
- Dawood Khan
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK.
| | - R Charlotte Moffett
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Andrei I Tarasov
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
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14
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Sarnobat D, Charlotte Moffett R, Flatt PR, Irwin N, Tarasov AI. GABA and insulin but not nicotinamide augment α- to β-cell transdifferentiation in insulin-deficient diabetic mice. Biochem Pharmacol 2022; 199:115019. [DOI: 10.1016/j.bcp.2022.115019] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/23/2022] [Accepted: 03/23/2022] [Indexed: 12/30/2022]
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15
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Holter MM, Saikia M, Cummings BP. Alpha-cell paracrine signaling in the regulation of beta-cell insulin secretion. Front Endocrinol (Lausanne) 2022; 13:934775. [PMID: 35957816 PMCID: PMC9360487 DOI: 10.3389/fendo.2022.934775] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/28/2022] [Indexed: 01/14/2023] Open
Abstract
As an incretin hormone, glucagon-like peptide 1 (GLP-1) lowers blood glucose levels by enhancing glucose-stimulated insulin secretion from pancreatic beta-cells. Therapies targeting the GLP-1 receptor (GLP-1R) use the classical incretin model as a physiological framework in which GLP-1 secreted from enteroendocrine L-cells acts on the beta-cell GLP-1R. However, this model has come into question, as evidence demonstrating local, intra-islet GLP-1 production has advanced the competing hypothesis that the incretin activity of GLP-1 may reflect paracrine signaling of GLP-1 from alpha-cells on GLP-1Rs on beta-cells. Additionally, recent studies suggest that alpha-cell-derived glucagon can serve as an additional, albeit less potent, ligand for the beta-cell GLP-1R, thereby expanding the role of alpha-cells beyond that of a counterregulatory cell type. Efforts to understand the role of the alpha-cell in the regulation of islet function have revealed both transcriptional and functional heterogeneity within the alpha-cell population. Further analysis of this heterogeneity suggests that functionally distinct alpha-cell subpopulations display alterations in islet hormone profile. Thus, the role of the alpha-cell in glucose homeostasis has evolved in recent years, such that alpha-cell to beta-cell communication now presents a critical axis regulating the functional capacity of beta-cells. Herein, we describe and integrate recent advances in our understanding of the impact of alpha-cell paracrine signaling on insulin secretory dynamics and how this intra-islet crosstalk more broadly contributes to whole-body glucose regulation in health and under metabolic stress. Moreover, we explore how these conceptual changes in our understanding of intra-islet GLP-1 biology may impact our understanding of the mechanisms of incretin-based therapeutics.
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Affiliation(s)
- Marlena M. Holter
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
- *Correspondence: Marlena M. Holter,
| | - Mridusmita Saikia
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Bethany P. Cummings
- School of Medicine, Department of Surgery, Center for Alimentary and Metabolic Sciences, University of California, Davis, Sacramento, CA, United States
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16
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Sarnobat D, Moffett RC, Flatt PR, Tarasov AI. Effects of first-line diabetes therapy with biguanides, sulphonylurea and thiazolidinediones on the differentiation, proliferation and apoptosis of islet cell populations. J Endocrinol Invest 2022; 45:95-103. [PMID: 34191257 PMCID: PMC8741670 DOI: 10.1007/s40618-021-01620-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/17/2021] [Indexed: 12/13/2022]
Abstract
AIMS Metformin, rosiglitazone and sulfonylureas enhance either insulin action or secretion and thus have been used extensively as early stage anti-diabetic medication, independently of the aetiology of the disease. When administered to newly diagnosed diabetes patients, these drugs produce variable results. Here, we examined the effects of the three early stage oral hypoglycaemic agents in mice with diabetes induced by multiple low doses of streptozotocin, focusing specifically on the developmental biology of pancreatic islets. METHODS Streptozotocin-treated diabetic mice expressing a fluorescent reporter specifically in pancreatic islet α-cells were administered the biguanide metformin (100 mg/kg), thiazolidinedione rosiglitazone (10 mg/kg), or sulfonylurea tolbutamide (20 mg/kg) for 10 days. We assessed the impact of the treatment on metabolic status of the animals as well as on the morphology, proliferative potential and transdifferentiation of pancreatic islet cells, using immunofluorescence. RESULTS The effect of the therapy on the islet cells varied depending on the drug and included enhanced pancreatic islet β-cell proliferation, in case of metformin and rosiglitazone; de-differentiation of α-cells and β-cell apoptosis with tolbutamide; increased relative number of β-cells and bi-hormonal insulin + glucagon + cells with metformin. These effects were accompanied by normalisation of food and fluid intake with only minor effects on glycaemia at the low doses of the agents employed. CONCLUSIONS Our data suggest that metformin and rosiglitazone attenuate the depletion of the β-cell pool in the streptozotocin-induced diabetes, whereas tolbutamide exacerbates the β-cell apoptosis, but is likely to protect β-cells from chronic hyperglycaemia by directly elevating insulin secretion.
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Affiliation(s)
- D Sarnobat
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
| | - R C Moffett
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
| | - P R Flatt
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
| | - A I Tarasov
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK.
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17
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Mohan S, Lafferty R, Tanday N, Flatt PR, Moffett RC, Irwin N. Beneficial impact of Ac3IV, an AVP analogue acting specifically at V1a and V1b receptors, on diabetes islet morphology and transdifferentiation of alpha- and beta-cells. PLoS One 2021; 16:e0261608. [PMID: 34929019 PMCID: PMC8687525 DOI: 10.1371/journal.pone.0261608] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 12/07/2021] [Indexed: 12/18/2022] Open
Abstract
Ac3IV (Ac-CYIQNCPRG-NH2) is an enzymatically stable vasopressin analogue that selectively activates Avpr1a (V1a) and Avpr1b (V1b) receptors. In the current study we have employed streptozotocin (STZ) diabetic transgenic Ins1Cre/+;Rosa26-eYFP and GluCreERT2;Rosa26-eYFP mice, to evaluate the impact of sustained Ac3IV treatment on pancreatic islet cell morphology and transdifferentiation. Twice-daily administration of Ac3IV (25 nmol/kg bw) to STZ-diabetic Ins1Cre/+;Rosa26-eYFP mice for 12 days increased pancreatic insulin (p<0.01) and significantly reversed the detrimental effects of STZ on pancreatic islet morphology. Such benefits were coupled with increased (p<0.01) beta-cell proliferation and decreased (p<0.05) beta-cell apoptosis. In terms of islet cell lineage tracing, induction of diabetes increased (p<0.001) beta- to alpha-cell differentiation in Ins1Cre/+;Rosa26-eYFP mice, with Ac3IV partially reversing (p<0.05) such transition events. Comparable benefits of Ac3IV on pancreatic islet architecture were observed in STZ-diabetic GluCreERT2;ROSA26-eYFP transgenic mice. In this model, Ac3IV provoked improvements in islet morphology which were linked to increased (p<0.05-p<0.01) transition of alpha- to beta-cells. Ac3IV also increased (p<0.05-p<0.01) CK-19 co-expression with insulin in pancreatic ductal and islet cells. Blood glucose levels were unchanged by Ac3IV in both models, reflecting the severity of diabetes induced. Taken together these data indicate that activation of islet receptors for V1a and V1b positively modulates alpha- and beta-cell turnover and endocrine cell lineage transition events to preserve beta-cell identity and islet architecture.
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Affiliation(s)
- Shruti Mohan
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Ryan Lafferty
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Neil Tanday
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Peter R. Flatt
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - R. Charlotte Moffett
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, United Kingdom
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18
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Mohan S, Flatt PR, Irwin N, Moffett RC. Weight-reducing, lipid-lowering and antidiabetic activities of a novel arginine vasopressin analogue acting at the V1a and V1b receptors in high-fat-fed mice. Diabetes Obes Metab 2021; 23:2215-2225. [PMID: 34105240 DOI: 10.1111/dom.14462] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 06/02/2021] [Accepted: 06/04/2021] [Indexed: 12/30/2022]
Abstract
AIM To assess the beneficial metabolic effects of the nonapeptide hormone, arginine vasopressin (AVP), on metabolism. MATERIALS AND METHODS We exchanged amino acids at position 3 and 8 of AVP, namely phenylalanine and arginine, with those of oxytocin, to generate novel analogues with altered receptor selectivity. Secondary modification by N-terminal acetylation was used to impart stability to circulating endopeptidases. Analogues were screened for degradation, bioactivity in rodent/human clonal beta cells and primary murine islets, together with evaluation of receptor activation profile. RESULTS Analogue Ac3IV, which lacked effects at the V2 receptors responsible for modulation of fluid balance, was selected as the lead compound for assessment of antidiabetic efficacy in high-fat-fed mice. Twice-daily administration of Ac3IV, or the gold standard control exendin-4, for 22 days, reduced energy intake as well as body weight and fat content. Both interventions decreased circulating glucose levels, enhanced insulin sensitivity, and substantially improved glucose tolerance and related insulin secretion in response to an intraperitoneal or oral glucose challenge. The peptides decreased total- and increased HDL-cholesterol, but only Ac3IV decreased LDL-cholesterol, triglyceride and non-fasting glucagon concentrations. Elevations of islet and beta-cell areas were partially reversed, accompanied by suppressed islet cell proliferation, decreased beta-cell apoptosis and, in the case of exendin-4, also decreased alpha-cell apoptosis. CONCLUSION AVP-based therapies that exclusively target V1a and V1b receptors may have significant therapeutic potential for the treatment of obesity and related diabetes, and merit further clinical exploration.
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Affiliation(s)
- Shruti Mohan
- 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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19
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Mechanisms of Beta-Cell Apoptosis in Type 2 Diabetes-Prone Situations and Potential Protection by GLP-1-Based Therapies. Int J Mol Sci 2021; 22:ijms22105303. [PMID: 34069914 PMCID: PMC8157542 DOI: 10.3390/ijms22105303] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/07/2021] [Accepted: 05/13/2021] [Indexed: 12/22/2022] Open
Abstract
Type 2 diabetes (T2D) is characterized by chronic hyperglycemia secondary to the decline of functional beta-cells and is usually accompanied by a reduced sensitivity to insulin. Whereas altered beta-cell function plays a key role in T2D onset, a decreased beta-cell mass was also reported to contribute to the pathophysiology of this metabolic disease. The decreased beta-cell mass in T2D is, at least in part, attributed to beta-cell apoptosis that is triggered by diabetogenic situations such as amyloid deposits, lipotoxicity and glucotoxicity. In this review, we discussed the molecular mechanisms involved in pancreatic beta-cell apoptosis under such diabetes-prone situations. Finally, we considered the molecular signaling pathways recruited by glucagon-like peptide-1-based therapies to potentially protect beta-cells from death under diabetogenic situations.
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20
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Lafferty RA, O’Harte FPM, Irwin N, Gault VA, Flatt PR. Proglucagon-Derived Peptides as Therapeutics. Front Endocrinol (Lausanne) 2021; 12:689678. [PMID: 34093449 PMCID: PMC8171296 DOI: 10.3389/fendo.2021.689678] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/05/2021] [Indexed: 12/12/2022] Open
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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21
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Zeigerer A, Sekar R, Kleinert M, Nason S, Habegger KM, Müller TD. Glucagon's Metabolic Action in Health and Disease. Compr Physiol 2021; 11:1759-1783. [PMID: 33792899 PMCID: PMC8513137 DOI: 10.1002/cphy.c200013] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Discovered almost simultaneously with insulin, glucagon is a pleiotropic hormone with metabolic action that goes far beyond its classical role to increase blood glucose. Albeit best known for its ability to directly act on the liver to increase de novo glucose production and to inhibit glycogen breakdown, glucagon lowers body weight by decreasing food intake and by increasing metabolic rate. Glucagon further promotes lipolysis and lipid oxidation and has positive chronotropic and inotropic effects in the heart. Interestingly, recent decades have witnessed a remarkable renaissance of glucagon's biology with the acknowledgment that glucagon has pharmacological value beyond its classical use as rescue medication to treat severe hypoglycemia. In this article, we summarize the multifaceted nature of glucagon with a special focus on its hepatic action and discuss the pharmacological potential of either agonizing or antagonizing the glucagon receptor for health and disease. © 2021 American Physiological Society. Compr Physiol 11:1759-1783, 2021.
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Affiliation(s)
- Anja Zeigerer
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Revathi Sekar
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Maximilian Kleinert
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Shelly Nason
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Kirk M. Habegger
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Timo D. Müller
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany
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22
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Tanday N, Moffett RC, Gault VA, Flatt PR, Irwin N. Enzymatically stable analogue of the gut-derived peptide xenin on beta-cell transdifferentiation in high fat fed and insulin-deficient Ins1 Cre/+ ;Rosa26-eYFP mice. Diabetes Metab Res Rev 2021; 37:e3384. [PMID: 32662136 DOI: 10.1002/dmrr.3384] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/25/2020] [Accepted: 07/06/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND The antidiabetic effects of the gut hormone xenin include augmenting insulin secretion and positively affecting pancreatic islet architecture. METHODS The current study has further probed pancreatic effects through sub-chronic administration of the long-acting xenin analogue, xenin-25[Lys13 PAL], in both high fat fed (HFF) and streptozotocin (STZ)-induced insulin-deficient Ins1Cre/+ ;Rosa26-eYFP transgenic mice. Parallel effects on metabolic control and pancreatic islet morphology, including islet beta-cell lineage tracing were also assessed. RESULTS Xenin-25[Lys13 PAL] treatment reversed body weight loss induced by STZ, increased plasma insulin and decreased blood glucose levels. There were less obvious effects on these parameters in HFF mice, but all xenin-25[Lys13 PAL] treated mice exhibited decreased pancreatic alpha-cell areas and circulating glucagon. Xenin-25[Lys13 PAL] treatment fully, or partially, returned overall islet and beta-cell areas in STZ- and HFF mice to those of lean control animals, respectively, and was consistently associated with decreased beta-cell apoptosis. Interestingly, xenin-25[Lys13 PAL] also increased beta-cell proliferation and decreased alpha-cell apoptosis in STZ mice, with reduced alpha-cell growth noted in HFF mice. Lineage tracing studies revealed that xenin-25[Lys13 PAL] reduced the number of insulin positive pancreatic islet cells that lost their beta-cell identity, in keeping with a decreased transition of insulin positive to glucagon positive cells. These beneficial effects on islet cell differentiation were linked to maintained expression of Pdx1 within beta-cells. Xenin-25[Lys13 PAL] treatment was also associated with increased numbers of smaller sized islets in both models. CONCLUSIONS Benefits of xenin-25[Lys13 PAL] on diabetes includes positive modulation of islet cell differentiation, in addition to promoting beta-cell growth and survival.
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Affiliation(s)
- Neil Tanday
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - R Charlotte Moffett
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Victor A Gault
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
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Musale V, Moffett RC, Conlon JM, Flatt PR, Abdel-Wahab YH. Beneficial actions of the [A14K] analog of the frog skin peptide PGLa-AM1 in mice with obesity and degenerative diabetes: A mechanistic study. Peptides 2021; 136:170472. [PMID: 33338546 DOI: 10.1016/j.peptides.2020.170472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/01/2020] [Accepted: 12/02/2020] [Indexed: 12/15/2022]
Abstract
The antidiabetic actions of [A14K]PGLa-AM1, an analog of peptide glycine-leucine-amide-AM1 isolated from skin secretions of the octoploid frog Xenopus amieti, were investigated in genetically diabetic-obese db/db mice. Twice daily administration of [A14K]PGLa-AM1 (75 nmol/kg body weight) for 28 days significantly (P < 0.05) decreased circulating blood glucose and HbA1c and increased plasma insulin concentrations leading to improvements in glucose tolerance. The elevated levels of triglycerides, LDL and cholesterol associated with the db/db phenotype were significantly reduced by peptide administration. Elevated plasma alanine transaminase, aspartic acid transaminase, and alkaline phosphatase activities and creatinine concentrations were also significantly decreased. Peptide treatment increased pancreatic insulin content and improved the responses of isolated islets to established insulin secretagogues. No significant changes in islet β-cell and α-cell areas were observed in [A14K]PGLa-AM1 treated mice but the loss of large and medium-size islets was prevented. Peptide administration resulted in a significant (P < 0.01) increase in islet expression of the gene encoding Pdx-1, a major transcription factor in islet cells determining β-cell survival and function, resulting in increased expression of genes involved with insulin secretion (Abcc8, Kcnj11, Slc2a2, Cacn1c) together with the genes encoding the incretin receptors Glp1r and Gipr. In addition, the elevated expression of insulin signalling genes (Slc2a4, Insr, Irs1, Akt1, Pik3ca, Ppm1b) in skeletal muscle associated with the db/db phenotype was downregulated by peptide treatment These data suggest that the anti-diabetic properties of [A14K]PGLa-AM1 are mediated by molecular changes that enhance both the secretion and action of insulin.
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Affiliation(s)
- Vishal Musale
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Northern Ireland, BT52 1SA, UK
| | - R Charlotte Moffett
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Northern Ireland, BT52 1SA, UK
| | - J Michael Conlon
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Northern Ireland, BT52 1SA, UK.
| | - Peter R Flatt
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Northern Ireland, BT52 1SA, UK
| | - Yasser H Abdel-Wahab
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Northern Ireland, BT52 1SA, UK
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24
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Mohan S, McCloskey AG, McKillop AM, Flatt PR, Irwin N, Moffett RC. Development and characterisation of novel, enzymatically stable oxytocin analogues with beneficial antidiabetic effects in high fat fed mice. Biochim Biophys Acta Gen Subj 2020; 1865:129811. [PMID: 33309687 DOI: 10.1016/j.bbagen.2020.129811] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND There is growing evidence to support beneficial effects of the hypothalamic synthesised hormone, oxytocin, on metabolism. However, the biological half-life of oxytocin is short and receptor activation profile unspecific. METHODS We have characterised peptide-based oxytocin analogues with structural modifications aimed at improving half-life and receptor specificity. Following extensive in vitro and in vivo characterisation, antidiabetic efficacy of lead peptides was examined in high fat fed (HFF) mice. RESULTS Following assessment of stability against enzymatic degradation, insulin secretory activity, receptor activation profile and in vivo bioactivity, analogues 2 N (Ac-C ˂YIQNC >PLG-NH2) and D7R ((d-C)YIQNCYLG-NH2) were selected as lead peptides. Twice daily injection of either peptide for 22 days reduced body weight, energy intake, plasma glucose and insulin and pancreatic glucagon content in HFF mice. In addition, both peptides reduced total- and LDL-cholesterol, with concomitant elevations of HDL-cholesterol, and D7R also decreased triglyceride levels. The two oxytocin analogues improved glucose tolerance and insulin responses to intraperitoneal, and particularly oral, glucose challenge on day 22. Both oxytocin analogues enhanced insulin sensitivity, reduced HOMA-IR and increased bone mineral density. In terms of pancreatic islet histology, D7R reversed high fat feeding induced elevations of islet and beta cell areas, which was associated with reductions in beta cell apoptosis. Islet insulin secretory responsiveness was improved by 2 N, and especially D7R, treatment. CONCLUSION Novel, enzymatically stable oxytocin analogues exert beneficial antidiabetic effects in HFF mice. GENERAL SIGNIFICANCE These observations emphasise the, yet untapped, therapeutic potential of long-acting oxytocin-based agents for obesity and type 2 diabetes.
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Affiliation(s)
- Shruti Mohan
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK
| | - Andrew G McCloskey
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK
| | - Aine M McKillop
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK.
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25
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The methionine aminopeptidase 2 inhibitor, TNP-470, enhances the antidiabetic properties of sitagliptin in mice by upregulating xenin. Biochem Pharmacol 2020; 183:114355. [PMID: 33279496 DOI: 10.1016/j.bcp.2020.114355] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/12/2020] [Accepted: 12/01/2020] [Indexed: 12/24/2022]
Abstract
The therapeutic mechanism of action of methionine aminopeptidase 2 (MetAP2) inhibitors for obesity-diabetes has not yet been fully defined. Xenin, a K-cell derived peptide hormone, possesses an N-terminal Met amino acid residue. Thus, elevated xenin levels could represent a potential pharmacological mechanism of MetAP2 inhibitors, since long-acting xenin analogues have been shown to improve obesity-diabetes. The present study has assessed the ability of the MetAP2 inhibitor, TNP-470, to augment the antidiabetic utility of the incretin-enhancer drug, sitagliptin, in high fat fed (HFF) mice. TNP-470 (1 mg/kg) and sitagliptin (25 mg/kg) were administered once-daily alone, or in combination, to diabetic HFF mice (n = 10) for 18 days. Individual therapy with TNP-470 or sitagliptin resulted in numerous metabolic benefits including reduced blood glucose, increased circulating and pancreatic insulin and improved glucose tolerance, insulin sensitivity, pyruvate tolerance and overall pancreatic islet architecture. Further assessment of metabolic rate revealed that all treatments reduced respiratory exchange ratio and increased locomotor activity. All sitagliptin treated mice also exhibited increased energy expenditure. In addition, treatment with TNP-470 alone, or in combination with sitagliptin, reduced food intake and body weight, as well as elevating plasma and intestinal xenin. Importantly, combined sitagliptin and TNP-470 therapy was associated with further significant benefits beyond that observed by either treatment alone. This included more rapid restoration of normoglycaemia, superior glucose tolerance, increased circulating GIP concentrations and an enhanced pancreatic beta:alpha cell ratio. In conclusion, these data demonstrate that TNP-470 increases plasma and intestinal xenin levels, and augments the antidiabetic advantages of sitagliptin.
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Sarnobat D, Moffett CR, Tanday N, Reimann F, Gribble FM, Flatt PR, Tarasov AI. Antidiabetic drug therapy alleviates type 1 diabetes in mice by promoting pancreatic α-cell transdifferentiation. Biochem Pharmacol 2020; 182:114216. [PMID: 32926875 PMCID: PMC7614179 DOI: 10.1016/j.bcp.2020.114216] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/03/2020] [Accepted: 09/04/2020] [Indexed: 12/17/2022]
Abstract
Gut incretins, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), enhance secretion of insulin in a glucose-dependent manner, predominantly by elevating cytosolic levels of cAMP in pancreatic β-cells. Successful targeting of the incretin pathway by several drugs, however, suggests the antidiabetic mechanism is likely to span beyond the acute effect on hormone secretion and include, for instance, stimulation of β-cell growth and/or proliferation. Likewise, the antidiabetic action of kidney sodium-glucose linked transporter-2 (SGLT-2) inhibitors exceeds simple increase glucose excretion. Potential reasons for these 'added benefits' may lie in the long-term effects of these signals on developmental aspects of pancreatic islet cells. In this work, we explored if the incretin mimetics or SGLT-2 inhibitors can affect the size of the islet α- or β-cell compartments, under the condition of β-cell stress. To that end, we utilised mice expressing YFP specifically in pancreatic α-cells, in which we modelled type 1 diabetes by injecting streptozotocin, followed by a 10-day administration of liraglutide, sitagliptin or dapagliflozin. We observed an onset of diabetic phenotype, which was partially reversed by the administration of the antidiabetic drugs. The mechanism for the reversal included induction of β-cell proliferation, decrease in β-cell apoptosis and, for the incretin mimetics, transdifferentiation of α-cells into β-cells. Our data therefore emphasize the role of chronic incretin signalling in induction of α-/β-cell transdifferentiation. We conclude that incretin peptides may act directly on islet cells, making use of the endogenous local sites of 'ectopic' expression, whereas SGLT-2 inhibitors work via protecting β-cells from chronic hyperglycaemia.
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Affiliation(s)
- Dipak Sarnobat
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, UK
| | - Charlotte R Moffett
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, UK
| | - Neil Tanday
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, UK
| | - Frank Reimann
- Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, CB2 0QQ, UK
| | - Fiona M Gribble
- Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, CB2 0QQ, UK
| | - Peter R Flatt
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, UK
| | - Andrei I Tarasov
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine BT52 1SA, UK.
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Tanday N, Irwin N, Moffett RC, Flatt PR, O'Harte FPM. Beneficial actions of a long-acting apelin analogue in diabetes are related to positive effects on islet cell turnover and transdifferentiation. Diabetes Obes Metab 2020; 22:2468-2478. [PMID: 32844576 DOI: 10.1111/dom.14177] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/10/2020] [Accepted: 08/23/2020] [Indexed: 12/19/2022]
Abstract
AIM The current study has tested the hypothesis that the positive effects of apelin receptor activation in diabetes are linked to benefits on islet cell apoptosis, proliferation and transdifferentiation using Ins1Cre/+ ;Rosa26-eYFP transgenic mice and induction of diabetes-like syndromes by streptozotocin (STZ) or high-fat feeding. MATERIALS AND METHODS Groups (n = 6-8) of streptozotocin (STZ)-induced diabetic and high-fat diet (HFD)-fed mice received once-daily injection (25 nmol/kg) of the long-acting acylated apelin-13 analogue, pGlu(Lys8 Glu-PAL)apelin-13 amide, for 10 or 12 days, respectively. RESULTS pGlu(Lys8 Glu-PAL)apelin-13 amide treatment partly reversed body weight loss induced by STZ and normalized circulating insulin. There was no effect of pGlu(Lys8 Glu-PAL)apelin-13 amide on these variables in HFD-fed mice, but an increase in pancreatic insulin content was observed. pGlu(Lys8 Glu-PAL)apelin-13 amide also fully, or partially, reversed the detrimental effects of STZ and HFD on plasma and pancreatic glucagon concentrations. In HFD-fed mice, the apelin analogue decreased dietary-induced elevations of islet, β- and α-cell areas, whilst reducing α-cell area in STZ-induced diabetic mice. In terms of islet cell lineage, pGlu(Lys8 Glu-PAL)apelin-13 amide effectively reduced β- to α-cell transdifferentiation and helped maintain β-cell identity, which was linked to elevated Pdx-1 expression. These islet effects were coupled with decreased β-cell apoptosis and α-cell proliferation in both models, and there was an accompanying increase of β-cell proliferation in STZ-induced diabetic mice. CONCLUSION Taken together these data demonstrate, for the first time, that pancreatic islet benefits of sustained APJ receptor activation in diabetes are linked to favourable islet cell transition events, leading to maintenance of β-cell mass.
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Affiliation(s)
- Neil Tanday
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - Nigel Irwin
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - R Charlotte Moffett
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - Peter R Flatt
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - Finbarr P M O'Harte
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK
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28
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Abstract
The islet of Langerhans is a complex endocrine micro-organ consisting of a multitude of endocrine and non-endocrine cell types. The two most abundant and prominent endocrine cell types, the beta and the alpha cells, are essential for the maintenance of blood glucose homeostasis. While the beta cell produces insulin, the only blood glucose-lowering hormone of the body, the alpha cell releases glucagon, which elevates blood glucose. Under physiological conditions, these two cell types affect each other in a paracrine manner. While the release products of the beta cell inhibit alpha cell function, the alpha cell releases factors that are stimulatory for beta cell function and increase glucose-stimulated insulin secretion. The aim of this review is to provide a comprehensive overview of recent research into the regulation of beta cell function by alpha cells, focusing on the effect of alpha cell-secreted factors, such as glucagon and acetylcholine. The consequences of differences in islet architecture between species on the interplay between alpha and beta cells is also discussed. Finally, we give a perspective on the possibility of using an in vivo imaging approach to study the interactions between human alpha and beta cells under in vivo conditions. Graphical abstract.
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Affiliation(s)
- Tilo Moede
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska Sjukhuset L1:03, 17176, Stockholm, Sweden.
| | - Ingo B Leibiger
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska Sjukhuset L1:03, 17176, Stockholm, Sweden
| | - Per-Olof Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska Sjukhuset L1:03, 17176, Stockholm, Sweden
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29
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Graham GV, Conlon JM, Abdel-Wahab YH, Flatt PR. Glucagon from the phylogenetically ancient paddlefish provides a template for the design of a long-acting peptide with effective anti-diabetic and anti-obesity activities. Eur J Pharmacol 2020; 878:173101. [PMID: 32320703 DOI: 10.1016/j.ejphar.2020.173101] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/26/2020] [Accepted: 04/06/2020] [Indexed: 12/13/2022]
Abstract
This study has examined the in vitro and in vivo anti-diabetic properties of the peptidase-resistant analogues [D-Ser2]palmitoyl-paddlefish glucagon and [D-Ser2]palmitoyl-lamprey glucagon. The peptides stimulated insulin release from BRIN-BD11 clonal β-cells and isolated mouse pancreatic islets and also enhanced cAMP production in cells transfected with the human GLP-1 receptor and with the human glucagon receptor. The insulinotropic actions of the peptides were attenuated in INS-1 cells lacking GLP-1 and glucagon receptors. [D-Ser2]palmitoyl-paddlefish glucagon stimulated proliferation of BRIN-BD11 cells and protected against cytokine-mediated apoptosis as effectively as GLP-1. The analogue was more effective than the native peptide or the lamprey glucagon analogue in acutely lowering blood glucose and elevating plasma insulin in lean mice even when administered up to 4 h before a glucose load. Twice daily administration of [D-Ser2]palmitoyl-paddlefish glucagon to high-fat fed mice over 21 days reduced food intake, body weight, non-fasting blood glucose and plasma insulin concentrations, as well as significantly improving glucose tolerance and insulin resistance and decreasing α-cell area and pancreatic insulin content. Islet expression of the Gcgr, Glp1r, Gipr and Slc2a2 (GLUT-2) genes significantly increased. These data demonstrate that long-acting peptide [D-Ser2]palmitoyl-paddlefish glucagon exerts beneficial metabolic properties in diabetic mice via Ggcr- and Glp1r-activated pathways and so shows potential as a template for further development into an agent for treatment of patients with obesity-related Type 2 diabetes.
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Affiliation(s)
- Galyna V Graham
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
| | - J Michael Conlon
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK.
| | - Yasser H Abdel-Wahab
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
| | - Peter R Flatt
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, UK
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Wongkrasant P, Pongkorpsakol P, Chitwattananont S, Satianrapapong W, Tuangkijkul N, Muanprasat C. Fructo-oligosaccharides alleviate inflammation-associated apoptosis of GLP-1 secreting L cells via inhibition of iNOS and cleaved caspase-3 expression. J Pharmacol Sci 2020; 143:65-73. [PMID: 32229084 DOI: 10.1016/j.jphs.2020.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 02/26/2020] [Accepted: 03/02/2020] [Indexed: 02/06/2023] Open
Abstract
Glucagon-like peptide 1 (GLP-1) released from enteroendocrine (L) cells regulates insulin secretion. Intestinal inflammation and impaired GLP-1 release have been found in type 2 diabetes mellitus (T2DM) patients. Fructo-oligosaccharides (FOS), a known prebiotic, improve GLP-1 release and glucose homeostasis in T2DM models. This study aimed to investigate the effect of tumor necrosis factor-α (TNF-α), a proinflammatory cytokine associated with intestinal inflammation in T2DM, on L cell apoptosis and the effect of FOS on inflammation-associated impairment of GLP-1 secretion. Herein, using cell death assays, immunofluorescence staining, real time PCR and Western blot analyses, we found that TNF-α induced L cell apoptosis via nuclear factor kappa B (NF-κB)- inducible nitric oxide synthase (iNOS)-cleaved caspase-3-dependent pathways. Interestingly, FOS did not suppress TNF-α-induced NF-κB nuclear translocation, but inhibited expression of iNOS and cleaved caspase-3. In addition, FOS alleviated apoptosis and rescued impaired GLP-1 release in TNF-α-treated L cells. Altogether, our data indicate that TNF-α induces L cell apoptosis via an NF-κB-iNOS-caspase-3-dependent pathway. FOS may be useful in suppressing inflammation-associated L cell apoptosis and maintaining GLP-1 level in T2DM patients.
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Affiliation(s)
- Preedajit Wongkrasant
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Rajathevi, Bangkok 10400, Thailand
| | - Pawin Pongkorpsakol
- Translational Medicine Graduate Program, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Rama VI Road, Rajathevi, Bangkok 10400, Thailand
| | - Sasirin Chitwattananont
- Translational Medicine Graduate Program, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Rama VI Road, Rajathevi, Bangkok 10400, Thailand
| | - Wilasinee Satianrapapong
- Translational Medicine Graduate Program, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Rama VI Road, Rajathevi, Bangkok 10400, Thailand
| | - Nuttha Tuangkijkul
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Samutprakarn 10540, Thailand
| | - Chatchai Muanprasat
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Samutprakarn 10540, Thailand; Excellent Center for Drug Discovery, Faculty of Science, Mahidol University, Bangkok, Thailand.
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31
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Ahrén B, Yamada Y, Seino Y. Islet adaptation in GIP receptor knockout mice. Peptides 2020; 125:170152. [PMID: 31522751 DOI: 10.1016/j.peptides.2019.170152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/01/2019] [Accepted: 09/02/2019] [Indexed: 12/27/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) receptor knockout (KO) mice are tools for studying GIP physiology. Previous results have demonstrated that these mice have impaired insulin response to oral glucose. In this study, we examined the insulin response to intravenous glucose by measuring glucose, insulin and C-peptide after intravenous glucose (0.35 g/kg) in 5-h fasted female GIP receptor KO mice and their wild-type (WT) littermates. The 1 min insulin and C-peptide responses to intravenous glucose were significantly enhanced in GIP receptor KO mice (n = 26) compared to WT mice (n = 30) as was beta cell function (area under the 50 min C-peptide curve divided by area under the 50 min curve for glucose) (P = 0.001). Beta cell function after intravenous glucose was also enhanced in GIP receptor KO mice in the presence of the glucagon-like peptide-1 receptor antagonist exendin 9 (30 nmol/kg; P = 0.007), the muscarinic antagonist atropine (5 mg/kg; P = 0.007) and the combination of the alpha-adrenoceptor antagonist yohimbine (1.4 mg/kg) and the beta-adrenoceptor antagonist propranolol (2.5 mg/kg; P = 0.042). Analysis of the regression between fasting glucose (6.8 ± 0.1 mmol/l in GIP receptor KO mice and 7.5 ± 0.2 mmol/l in WT mice, P = 0.003) and the 1 min C-peptide response to intravenous glucose showed a negative linear regression between these variables in both WT (n = 60; r = -0.425, P = 0.001) and GIP receptor KO mice (n = 56; r = -0.474, P < 0.001). We conclude that there is a beta cell adaptation in GIP receptor KO mice resulting in enhanced insulin secretion after intravenous glucose to which slight long-term reduction in circulating glucose in these mice may contribute.
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Affiliation(s)
- Bo Ahrén
- Department of Clinical Sciences Lund, Lund university, Lund, Sweden.
| | - Yuchiro Yamada
- Department of Endocrinology, Diabetes and Geriatric Medicine, Graduate School of Medicine, Akita University, Akita, Japan
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32
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Sarnobat D, Moffett RC, Gault VA, Tanday N, Reimann F, Gribble FM, Flatt PR, Irwin N. Effects of long-acting GIP, xenin and oxyntomodulin peptide analogues on alpha-cell transdifferentiation in insulin-deficient diabetic Glu CreERT2;ROSA26-eYFP mice. Peptides 2020; 125:170205. [PMID: 31738969 PMCID: PMC7212078 DOI: 10.1016/j.peptides.2019.170205] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/08/2019] [Accepted: 11/13/2019] [Indexed: 02/08/2023]
Abstract
Enzyme-resistant long-acting forms of the gut-derived peptide hormones, glucose-dependent insulinotropic polypeptide (GIP), xenin and oxyntomodulin (Oxm) have been generated, and exert beneficial effects on diabetes control and pancreatic islet architecture. The current study has employed alpha-cell lineage tracing in GluCreERT2;ROSA26-eYFP transgenic mice to investigate the extent to which these positive pancreatic effects are associated with alpha- to beta-cell transdifferentiation. Twice-daily administration of (D-Ala2)GIP, xenin-25[Lys13PAL] or (D-Ser2)-Oxm[Lys38PAL] for 10 days to streptozotocin (STZ)-induced diabetic mice did not affect body weight, food intake or blood glucose levels, but (D-Ser2)-Oxm[Lys38PAL] reduced (P < 0.05 to P < 0.001) fluid intake and circulating glucagon. (D-Ala2)GIP and (D-Ser2)-Oxm[Lys38PAL] also augmented (P < 0.05 and P < 0.01, respectively) pancreatic insulin content. Detrimental changes of pancreatic morphology induced by STZ in GluCreERT2;ROSA26-eYFP mice were partially reversed by all treatment interventions. This was associated with reduced (P < 0.05) apoptosis and increased (P < 0.05 to P < 0.01) proliferation of beta-cells, alongside opposing effects on alpha-cells, with (D-Ala2)GIP and (D-Ser2)-Oxm[Lys38PAL] being particularly effective in this regard. Alpha-cell lineage tracing revealed that induction of diabetes was accompanied by increased (P < 0.01) transdifferentiation of glucagon positive alpha-cells to insulin positive beta-cells. This islet cell transitioning process was augmented (P < 0.01 and P < 0.001, respectively) by (D-Ala2)GIP and (D-Ser2)-Oxm[Lys38PAL]. (D-Ser2)-Oxm[Lys38PAL] also significantly (P < 0.05) promoted loss of alpha-cell identity in favour of other endocrine islet cells. These data highlight intra-islet benefits of (D-Ala2)GIP, xenin-25[Lys13PAL] and (D-Ser2)-Oxm[Lys38PAL] in diabetes with beta-cell loss induced by STZ. The effects appear to be independent of glycaemic change, and associated with alpha- to beta-cell transdifferentiation for the GIP and Oxm analogues.
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Affiliation(s)
- Dipak Sarnobat
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - R Charlotte Moffett
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Victor A Gault
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Neil Tanday
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Frank Reimann
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Fiona M Gribble
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK.
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Graham GV, McCloskey A, Abdel-Wahab YH, Conlon JM, Flatt PR. A long-acting, dual-agonist analogue of lamprey GLP-1 shows potent insulinotropic, β-cell protective, and anorexic activities and improves glucose homeostasis in high fat-fed mice. Mol Cell Endocrinol 2020; 499:110584. [PMID: 31539596 DOI: 10.1016/j.mce.2019.110584] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/05/2019] [Accepted: 09/16/2019] [Indexed: 12/12/2022]
Abstract
Peptidase-resistant analogues of GLP-1 peptides from sea lamprey and paddlefish ([D-Ala2]palmitoyl-lamprey GLP-1 and [D-Ala2]palmitoyl-paddlefish GLP-1) produced significant (P ≤ 0.05) and concentration-dependent increases in insulin release from BRIN-BD11 clonal β-cells and from isolated mouse islets. Both analogues retained the ability of the native peptides to activate both the GLP-1 receptor (GLP1R) and the glucagon receptor (GCGR). [D-Ala2]palmitoyl-lamprey GLP-1 significantly (P < 0.001) stimulated proliferation of BRIN-BD11 cells and protected against cytokine-induced apoptosis. Administration of the lamprey analogue (25 nmol/kg body weight) to lean mice up to 4 h before a glucose load improved glucose tolerance and increased plasma insulin concentrations. Twice daily administration of the lamprey GLP-1 analogue to high fat-fed mice for 21 days decreased body weight, food intake, and circulating glucose and insulin concentrations. The analogue significantly improved glucose tolerance and insulin sensitivity with beneficial effects on islet β-cell area and insulin secretory responsiveness. Islet gene expression of Glp1r, Gcgr and Gipr significantly increased. The lamprey GLP-1 analogue shows therapeutic promise for treatment of patients with obesity-related Type 2 diabetes.
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Affiliation(s)
- Galyna V Graham
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland BT52 1SA, UK
| | - Andrew McCloskey
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland BT52 1SA, UK
| | - Yasser H Abdel-Wahab
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland BT52 1SA, UK
| | - J Michael Conlon
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland BT52 1SA, UK.
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland BT52 1SA, UK
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Antidiabetic effects and sustained metabolic benefits of sub-chronic co-administration of exendin-4/gastrin and xenin-8-Gln in high fat fed mice. Eur J Pharmacol 2019; 865:172733. [PMID: 31614140 DOI: 10.1016/j.ejphar.2019.172733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 10/09/2019] [Accepted: 10/11/2019] [Indexed: 11/20/2022]
Abstract
The present study has examined the antidiabetic effects of 21 days co-administration of xenin-8-Gln with the dual-acting fusion peptide, exendin-4/gastrin, as well as persistence of beneficial metabolic benefits, in high fat fed (HFF) mice. Xenin-8-Gln, exendin-4 and gastrin represent compounds that activate receptors of the gut-derived hormones, xenin, glucagon-like peptide-1 (GLP-1) and gastrin, respectively. Twice-daily administration of exendin-4/gastrin, xenin-8-Gln or a combination of both peptides significantly reduced circulating glucose, HbA1c and cumulative energy intake. Combination therapy with xenin-8-Gln and exendin-4/gastrin increased circulating insulin. All HFF mice treated with exendin-4/gastrin presented with body weight similar to lean control mice on day 21. Each treatment improved glucose tolerance and the glucose-lowering actions of glucose dependent insulinotropic polypeptide (GIP), as well as augmenting glucose- and GIP-induced insulin secretion, with benefits being most prominent in the combination group. Administration of exendin-4/gastrin alone, and in combination with xenin-8-Gln, increased pancreatic insulin content and improved the insulin sensitivity index. Pancreatic beta-cell area was significantly increased, and alpha cell area decreased, by all treatments, with the combination group also displaying enhanced overall islet area. Notably, metabolic benefits were generally retained in all groups of HFF mice, and especially in the combination group, following discontinuation of the treatment regimens for 21 days. This was associated with maintenance of increased islet and beta-cell areas. Together, these data confirm the antidiabetic effects of co-activation of GLP-1, gastrin and xenin cell signalling pathways, and highlight the sustainable benefits this type of treatment paradigm can offer in T2DM.
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Müller TD, Finan B, Bloom SR, D'Alessio D, Drucker DJ, Flatt PR, Fritsche A, Gribble F, Grill HJ, Habener JF, Holst JJ, Langhans W, Meier JJ, Nauck MA, Perez-Tilve D, Pocai A, Reimann F, Sandoval DA, Schwartz TW, Seeley RJ, Stemmer K, Tang-Christensen M, Woods SC, DiMarchi RD, Tschöp MH. Glucagon-like peptide 1 (GLP-1). Mol Metab 2019; 30:72-130. [PMID: 31767182 PMCID: PMC6812410 DOI: 10.1016/j.molmet.2019.09.010] [Citation(s) in RCA: 862] [Impact Index Per Article: 172.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/10/2019] [Accepted: 09/22/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The glucagon-like peptide-1 (GLP-1) is a multifaceted hormone with broad pharmacological potential. Among the numerous metabolic effects of GLP-1 are the glucose-dependent stimulation of insulin secretion, decrease of gastric emptying, inhibition of food intake, increase of natriuresis and diuresis, and modulation of rodent β-cell proliferation. GLP-1 also has cardio- and neuroprotective effects, decreases inflammation and apoptosis, and has implications for learning and memory, reward behavior, and palatability. Biochemically modified for enhanced potency and sustained action, GLP-1 receptor agonists are successfully in clinical use for the treatment of type-2 diabetes, and several GLP-1-based pharmacotherapies are in clinical evaluation for the treatment of obesity. SCOPE OF REVIEW In this review, we provide a detailed overview on the multifaceted nature of GLP-1 and its pharmacology and discuss its therapeutic implications on various diseases. MAJOR CONCLUSIONS Since its discovery, GLP-1 has emerged as a pleiotropic hormone with a myriad of metabolic functions that go well beyond its classical identification as an incretin hormone. The numerous beneficial effects of GLP-1 render this hormone an interesting candidate for the development of pharmacotherapies to treat obesity, diabetes, and neurodegenerative disorders.
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Affiliation(s)
- T D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany.
| | - B Finan
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA
| | - S R Bloom
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - D D'Alessio
- Division of Endocrinology, Duke University Medical Center, Durham, NC, USA
| | - D J Drucker
- The Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, University of Toronto, Ontario, M5G1X5, Canada
| | - P R Flatt
- SAAD Centre for Pharmacy & Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - A Fritsche
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany; Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, Tübingen, Germany
| | - F Gribble
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - H J Grill
- Institute of Diabetes, Obesity and Metabolism, Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - J F Habener
- Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Harvard University, Boston, MA, USA
| | - J J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - W Langhans
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - J J Meier
- Diabetes Division, St Josef Hospital, Ruhr-University Bochum, Bochum, Germany
| | - M A Nauck
- Diabetes Center Bochum-Hattingen, St Josef Hospital (Ruhr-Universität Bochum), Bochum, Germany
| | - D Perez-Tilve
- Department of Internal Medicine, University of Cincinnati-College of Medicine, Cincinnati, OH, USA
| | - A Pocai
- Cardiovascular & ImmunoMetabolism, Janssen Research & Development, Welsh and McKean Roads, Spring House, PA, 19477, USA
| | - F Reimann
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - D A Sandoval
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - T W Schwartz
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, DL-2200, Copenhagen, Denmark; Department of Biomedical Sciences, University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - R J Seeley
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - K Stemmer
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - M Tang-Christensen
- Obesity Research, Global Drug Discovery, Novo Nordisk A/S, Måløv, Denmark
| | - S C Woods
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, USA
| | - R D DiMarchi
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA; Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - M H Tschöp
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany; Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
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Song Y, Koehler JA, Baggio LL, Powers AC, Sandoval DA, Drucker DJ. Gut-Proglucagon-Derived Peptides Are Essential for Regulating Glucose Homeostasis in Mice. Cell Metab 2019; 30:976-986.e3. [PMID: 31495689 PMCID: PMC8140521 DOI: 10.1016/j.cmet.2019.08.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 07/03/2019] [Accepted: 08/09/2019] [Indexed: 12/22/2022]
Abstract
The importance of pancreatic versus intestinal-derived GLP-1 for glucose homeostasis is controversial. We detected active GLP-1 in the mouse and human pancreas, albeit at extremely low levels relative to glucagon. Accordingly, to elucidate the metabolic importance of intestinal proglucagon-derived peptides (PGDPs), we generated mice with reduction of Gcg expression within the distal (GcgDistalGut-/-) or entire (GcgGut-/-) gut. Substantial reduction of gut Gcg expression markedly reduced circulating levels of GLP-1, and impaired glucose homeostasis, associated with increased levels of GIP, and accelerated gastric emptying. GcgDistalGut-/- mice similarly exhibited lower circulating GLP-1 and impaired oral glucose tolerance. Nevertheless, plasma levels of insulin remained normal following glucose administration in the absence of gut-derived GLP-1. Collectively, our findings identify the essential importance of gut-derived PGDPs for maintaining levels of circulating GLP-1, control of gastric emptying, and glucose homeostasis.
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Affiliation(s)
- Youngmi Song
- Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, University of Toronto, Toronto, ON M5G1X5, Canada; Medical Research Institute, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Jacqueline A Koehler
- Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, University of Toronto, Toronto, ON M5G1X5, Canada
| | - Laurie L Baggio
- Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, University of Toronto, Toronto, ON M5G1X5, Canada
| | - Alvin C Powers
- Department of Medicine, Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN 37232-0475, USA; Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA; Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, USA
| | | | - Daniel J Drucker
- Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, University of Toronto, Toronto, ON M5G1X5, Canada.
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Tomas A, Jones B, Leech C. New Insights into Beta-Cell GLP-1 Receptor and cAMP Signaling. J Mol Biol 2019; 432:1347-1366. [PMID: 31446075 DOI: 10.1016/j.jmb.2019.08.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 08/06/2019] [Accepted: 08/13/2019] [Indexed: 12/14/2022]
Abstract
Harnessing the translational potential of the GLP-1/GLP-1R system in pancreatic beta cells has led to the development of established GLP-1R-based therapies for the long-term preservation of beta cell function. In this review, we discuss recent advances in the current research on the GLP-1/GLP-1R system in beta cells, including the regulation of signaling by endocytic trafficking as well as the application of concepts such as signal bias, allosteric modulation, dual agonism, polymorphic receptor variants, spatial compartmentalization of cAMP signaling and new downstream signaling targets involved in the control of beta cell function.
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Affiliation(s)
- Alejandra Tomas
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, W12 0NN, UK.
| | - Ben Jones
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, W12 0NN, UK
| | - Colin Leech
- Department of Surgery, State University of New York, Upstate Medical University, Syracuse, NY, 13210, USA
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Mohan S, Moffett RC, Thomas KG, Irwin N, Flatt PR. Vasopressin receptors in islets enhance glucose tolerance, pancreatic beta-cell secretory function, proliferation and survival. Biochimie 2019; 158:191-198. [DOI: 10.1016/j.biochi.2019.01.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 01/15/2019] [Indexed: 12/12/2022]
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Baeyens L, Lemper M, Staels W, De Groef S, De Leu N, Heremans Y, German MS, Heimberg H. (Re)generating Human Beta Cells: Status, Pitfalls, and Perspectives. Physiol Rev 2018; 98:1143-1167. [PMID: 29717931 DOI: 10.1152/physrev.00034.2016] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Diabetes mellitus results from disturbed glucose homeostasis due to an absolute (type 1) or relative (type 2) deficiency of insulin, a peptide hormone almost exclusively produced by the beta cells of the endocrine pancreas in a tightly regulated manner. Current therapy only delays disease progression through insulin injection and/or oral medications that increase insulin secretion or sensitivity, decrease hepatic glucose production, or promote glucosuria. These drugs have turned diabetes into a chronic disease as they do not solve the underlying beta cell defects or entirely prevent the long-term complications of hyperglycemia. Beta cell replacement through islet transplantation is a more physiological therapeutic alternative but is severely hampered by donor shortage and immune rejection. A curative strategy should combine newer approaches to immunomodulation with beta cell replacement. Success of this approach depends on the development of practical methods for generating beta cells, either in vitro or in situ through beta cell replication or beta cell differentiation. This review provides an overview of human beta cell generation.
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Affiliation(s)
- Luc Baeyens
- Beta Cell Neogenesis (BENE), Vrije Universiteit Brussel, Brussels , Belgium ; Diabetes Center, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, and Department of Medicine, University of California San Francisco , San Francisco, California ; Genentech Safety Assessment, South San Francisco, California ; Investigative Toxicology, UCB BioPharma, Braine-l'Alleud, Belgium ; Department of Pediatrics, Division of Pediatric Endocrinology, Ghent University, Hospital and Department of Pediatrics and Genetics , Ghent , Belgium ; Department of Endocrinology, Universitair Ziekenhuis Brussel, Brussels , Belgium ; and Department of Endocrinology, Algemeen Stedelijk Ziekenhuis Aalst, Aalst, Belgium
| | - Marie Lemper
- Beta Cell Neogenesis (BENE), Vrije Universiteit Brussel, Brussels , Belgium ; Diabetes Center, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, and Department of Medicine, University of California San Francisco , San Francisco, California ; Genentech Safety Assessment, South San Francisco, California ; Investigative Toxicology, UCB BioPharma, Braine-l'Alleud, Belgium ; Department of Pediatrics, Division of Pediatric Endocrinology, Ghent University, Hospital and Department of Pediatrics and Genetics , Ghent , Belgium ; Department of Endocrinology, Universitair Ziekenhuis Brussel, Brussels , Belgium ; and Department of Endocrinology, Algemeen Stedelijk Ziekenhuis Aalst, Aalst, Belgium
| | - Willem Staels
- Beta Cell Neogenesis (BENE), Vrije Universiteit Brussel, Brussels , Belgium ; Diabetes Center, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, and Department of Medicine, University of California San Francisco , San Francisco, California ; Genentech Safety Assessment, South San Francisco, California ; Investigative Toxicology, UCB BioPharma, Braine-l'Alleud, Belgium ; Department of Pediatrics, Division of Pediatric Endocrinology, Ghent University, Hospital and Department of Pediatrics and Genetics , Ghent , Belgium ; Department of Endocrinology, Universitair Ziekenhuis Brussel, Brussels , Belgium ; and Department of Endocrinology, Algemeen Stedelijk Ziekenhuis Aalst, Aalst, Belgium
| | - Sofie De Groef
- Beta Cell Neogenesis (BENE), Vrije Universiteit Brussel, Brussels , Belgium ; Diabetes Center, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, and Department of Medicine, University of California San Francisco , San Francisco, California ; Genentech Safety Assessment, South San Francisco, California ; Investigative Toxicology, UCB BioPharma, Braine-l'Alleud, Belgium ; Department of Pediatrics, Division of Pediatric Endocrinology, Ghent University, Hospital and Department of Pediatrics and Genetics , Ghent , Belgium ; Department of Endocrinology, Universitair Ziekenhuis Brussel, Brussels , Belgium ; and Department of Endocrinology, Algemeen Stedelijk Ziekenhuis Aalst, Aalst, Belgium
| | - Nico De Leu
- Beta Cell Neogenesis (BENE), Vrije Universiteit Brussel, Brussels , Belgium ; Diabetes Center, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, and Department of Medicine, University of California San Francisco , San Francisco, California ; Genentech Safety Assessment, South San Francisco, California ; Investigative Toxicology, UCB BioPharma, Braine-l'Alleud, Belgium ; Department of Pediatrics, Division of Pediatric Endocrinology, Ghent University, Hospital and Department of Pediatrics and Genetics , Ghent , Belgium ; Department of Endocrinology, Universitair Ziekenhuis Brussel, Brussels , Belgium ; and Department of Endocrinology, Algemeen Stedelijk Ziekenhuis Aalst, Aalst, Belgium
| | - Yves Heremans
- Beta Cell Neogenesis (BENE), Vrije Universiteit Brussel, Brussels , Belgium ; Diabetes Center, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, and Department of Medicine, University of California San Francisco , San Francisco, California ; Genentech Safety Assessment, South San Francisco, California ; Investigative Toxicology, UCB BioPharma, Braine-l'Alleud, Belgium ; Department of Pediatrics, Division of Pediatric Endocrinology, Ghent University, Hospital and Department of Pediatrics and Genetics , Ghent , Belgium ; Department of Endocrinology, Universitair Ziekenhuis Brussel, Brussels , Belgium ; and Department of Endocrinology, Algemeen Stedelijk Ziekenhuis Aalst, Aalst, Belgium
| | - Michael S German
- Beta Cell Neogenesis (BENE), Vrije Universiteit Brussel, Brussels , Belgium ; Diabetes Center, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, and Department of Medicine, University of California San Francisco , San Francisco, California ; Genentech Safety Assessment, South San Francisco, California ; Investigative Toxicology, UCB BioPharma, Braine-l'Alleud, Belgium ; Department of Pediatrics, Division of Pediatric Endocrinology, Ghent University, Hospital and Department of Pediatrics and Genetics , Ghent , Belgium ; Department of Endocrinology, Universitair Ziekenhuis Brussel, Brussels , Belgium ; and Department of Endocrinology, Algemeen Stedelijk Ziekenhuis Aalst, Aalst, Belgium
| | - Harry Heimberg
- Beta Cell Neogenesis (BENE), Vrije Universiteit Brussel, Brussels , Belgium ; Diabetes Center, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, and Department of Medicine, University of California San Francisco , San Francisco, California ; Genentech Safety Assessment, South San Francisco, California ; Investigative Toxicology, UCB BioPharma, Braine-l'Alleud, Belgium ; Department of Pediatrics, Division of Pediatric Endocrinology, Ghent University, Hospital and Department of Pediatrics and Genetics , Ghent , Belgium ; Department of Endocrinology, Universitair Ziekenhuis Brussel, Brussels , Belgium ; and Department of Endocrinology, Algemeen Stedelijk Ziekenhuis Aalst, Aalst, Belgium
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Gupta R, Nguyen DC, Schaid MD, Lei X, Balamurugan AN, Wong GW, Kim JA, Koltes JE, Kimple ME, Bhatnagar S. Complement 1q-like-3 protein inhibits insulin secretion from pancreatic β-cells via the cell adhesion G protein-coupled receptor BAI3. J Biol Chem 2018; 293:18086-18098. [PMID: 30228187 DOI: 10.1074/jbc.ra118.005403] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/06/2018] [Indexed: 01/04/2023] Open
Abstract
Secreted proteins are important metabolic regulators in both healthy and disease states. Here, we sought to investigate the mechanism by which the secreted protein complement 1q-like-3 (C1ql3) regulates insulin secretion from pancreatic β-cells, a key process affecting whole-body glucose metabolism. We found that C1ql3 predominantly inhibits exendin-4- and cAMP-stimulated insulin secretion from mouse and human islets. However, to a lesser extent, C1ql3 also reduced insulin secretion in response to KCl, the potassium channel blocker tolbutamide, and high glucose. Strikingly, C1ql3 did not affect insulin secretion stimulated by fatty acids, amino acids, or mitochondrial metabolites, either at low or submaximal glucose concentrations. Additionally, C1ql3 inhibited glucose-stimulated cAMP levels, and insulin secretion stimulated by exchange protein directly activated by cAMP-2 and protein kinase A. These results suggest that C1ql3 inhibits insulin secretion primarily by regulating cAMP signaling. The cell adhesion G protein-coupled receptor, brain angiogenesis inhibitor-3 (BAI3), is a C1ql3 receptor and is expressed in β-cells and in mouse and human islets, but its function in β-cells remained unknown. We found that siRNA-mediated Bai3 knockdown in INS1(832/13) cells increased glucose-stimulated insulin secretion. Furthermore, incubating the soluble C1ql3-binding fragment of the BAI3 protein completely blocked the inhibitory effects of C1ql3 on insulin secretion in response to cAMP. This suggests that BAI3 mediates the inhibitory effects of C1ql3 on insulin secretion from pancreatic β-cells. These findings demonstrate a novel regulatory mechanism by which C1ql3/BAI3 signaling causes an impairment of insulin secretion from β-cells, possibly contributing to the progression of type 2 diabetes in obesity.
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Affiliation(s)
- Rajesh Gupta
- From the Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, and Comprehensive Diabetes Center, University of Alabama, Birmingham, Alabama 35294
| | - Dan C Nguyen
- From the Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, and Comprehensive Diabetes Center, University of Alabama, Birmingham, Alabama 35294
| | - Michael D Schaid
- the Interdisciplinary Graduate Program in Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706,; the William S. Middleton Memorial Veterans Hospital, Research Service, Madison, Wisconsin 53705
| | - Xia Lei
- the Department of Physiology and Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | | | - G William Wong
- the Department of Physiology and Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Jeong-A Kim
- From the Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, and Comprehensive Diabetes Center, University of Alabama, Birmingham, Alabama 35294
| | - James E Koltes
- the Department of Animal Science, Iowa State University, Ames, Iowa 50011
| | - Michelle E Kimple
- the Interdisciplinary Graduate Program in Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706,; the William S. Middleton Memorial Veterans Hospital, Research Service, Madison, Wisconsin 53705,; the Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, and the Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin 53705
| | - Sushant Bhatnagar
- From the Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, and Comprehensive Diabetes Center, University of Alabama, Birmingham, Alabama 35294,.
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Hasib A, Ng MT, Khan D, Gault VA, Flatt PR, Irwin N. Characterisation and antidiabetic utility of a novel hybrid peptide, exendin-4/gastrin/xenin-8-Gln. Eur J Pharmacol 2018; 834:126-135. [DOI: 10.1016/j.ejphar.2018.07.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/29/2018] [Accepted: 07/13/2018] [Indexed: 12/14/2022]
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Kanda R, Hiraike H, Wada-Hiraike O, Ichinose T, Nagasaka K, Sasajima Y, Ryo E, Fujii T, Osuga Y, Ayabe T. Expression of the glucagon-like peptide-1 receptor and its role in regulating autophagy in endometrial cancer. BMC Cancer 2018; 18:657. [PMID: 29907137 PMCID: PMC6003019 DOI: 10.1186/s12885-018-4570-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 05/31/2018] [Indexed: 12/13/2022] Open
Abstract
Background A previous report showed that a glucagon-like peptide-1 receptor (GLP-1R) agonist (exenatide) induced apoptosis in endometrial cancer cells. However, the pathophysiological role of GLP-1R in endometrial cancer has not been fully elucidated. Here, we investigated the effects of the GLP-1R agonist liraglutide in endometrial cancer cells and examined the association between GLP-1R expression and clinicopathological characteristics in endometrial cancer patients. Methods Human Ishikawa endometrial cancer cells were treated with different concentrations of liraglutide. To assess the effects of liraglutide, cell viability, colony formation, flow cytometry, Western blotting, and immunofluorescence assays were performed. Autophagy induction was examined by analyzing LC3 and p62 expression and autophagosome accumulation. Moreover, using a tissue microarray, we analyzed GLP-1R expression in 154 endometrial cancer tissue samples by immunohistochemistry. Results In accordance with the previous report, liraglutide inhibited Ishikawa cell growth in a dose-dependent manner. Liraglutide significantly induced autophagy, and phosphorylated AMPK expression was elevated. Immunohistochemical analysis revealed that GLP-1R expression was associated with positive estrogen receptor and progesterone receptor status, and higher GLP-1R expression was significantly correlated with better progression-free survival. Conclusions The use of liraglutide to target autophagy in endometrial cancer cells may be a novel potential treatment for endometrial cancer. Furthermore, higher GLP-1R expression may be associated with better prognosis in endometrial cancer patients. Electronic supplementary material The online version of this article (10.1186/s12885-018-4570-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ranka Kanda
- Department of Obstetrics and Gynecology, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo, 173 0003, Japan
| | - Haruko Hiraike
- Department of Obstetrics and Gynecology, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo, 173 0003, Japan.
| | - Osamu Wada-Hiraike
- Department of Obstetrics and Gynecology, The University of Tokyo, Tokyo, Japan
| | - Takayuki Ichinose
- Department of Obstetrics and Gynecology, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo, 173 0003, Japan
| | - Kazunori Nagasaka
- Department of Obstetrics and Gynecology, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo, 173 0003, Japan
| | - Yuko Sasajima
- Department of Pathology, Teikyo University School of Medicine, Tokyo, Japan
| | - Eiji Ryo
- Department of Obstetrics and Gynecology, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo, 173 0003, Japan
| | - Tomoyuki Fujii
- Department of Obstetrics and Gynecology, The University of Tokyo, Tokyo, Japan
| | - Yutaka Osuga
- Department of Obstetrics and Gynecology, The University of Tokyo, Tokyo, Japan
| | - Takuya Ayabe
- Department of Obstetrics and Gynecology, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo, 173 0003, Japan
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Wang F, Wu J, Qiu Z, Ge X, Liu X, Zhang C, Xu W, Wang F, Hua D, Qi X, Mao Y. ACOT1 expression is associated with poor prognosis in gastric adenocarcinoma. Hum Pathol 2018; 77:35-44. [PMID: 29555575 DOI: 10.1016/j.humpath.2018.03.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 03/04/2018] [Accepted: 03/09/2018] [Indexed: 02/06/2023]
Abstract
Acyl-CoA thioesterase 1 (ACOT1) is an important isoform of the ACOT family that catalyzes the reaction of fatty acyl-CoAs to CoA-SH and free fatty acids. Recent studies of gastrointestinal tumor metabolism suggest that there is abnormal metabolism of lipids and fatty acids during tumor progression. However, the function and contribution of ACOT1 in gastric cancer development are still poorly understood. In addition, GLI3 is a major transcription factor in the regulation of hedgehog signaling. GLI3 mutations induce glandular expansion and intestinal metaplasia in gastric cancer, which indicates a role for GLI3 in the preneoplastic process. Thus, we investigated the relationship between ACOT1 expression and GLI3 in gastric adenocarcinoma. A tissue microarray was constructed from 280 cases of gastric adenocarcinoma. The immunohistochemistry method was performed on tissue sections of 4 μm from each tissue microarray block. We found a significant correlation between ACOT1 expression and poor histologic grade, a lower T category, TNM stage, and increased GLI3 expression. In addition, the survival analysis revealed that the ACOT1-positive group had significantly decreased overall survival rates compared with the ACOT1-negative group. Furthermore, GLI3 expression had a significant positive correlation with ACOT1 expression in gastric adenocarcinoma cells. In summary, these findings demonstrate that increased expression of ACOT1 is correlated with pivotal clinicopathological parameters and poor prognosis in gastric adenocarcinoma through increased expression of the potential tumor-promoting protein GLI3.
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Affiliation(s)
- Fang Wang
- Department of Oncology, Affiliated Hospital of Jiangnan University, Wuxi, China, 214062; Jiangnan University School of Medicine, Wuxi, China, 214000
| | - Jingyi Wu
- Department of Oncology, Affiliated Hospital of Jiangnan University, Wuxi, China, 214062; Jiangnan University School of Medicine, Wuxi, China, 214000
| | - Zhichao Qiu
- Department of Oncology, Affiliated Hospital of Jiangnan University, Wuxi, China, 214062; Jiangnan University School of Medicine, Wuxi, China, 214000
| | - Xiaosong Ge
- Department of Oncology, Affiliated Hospital of Jiangnan University, Wuxi, China, 214062
| | - Xingxiang Liu
- Department of Oncology, Second People's Hospital of Taizhou City, Taizhou, China, 225300
| | - Chun Zhang
- Jiangnan University School of Medicine, Wuxi, China, 214000
| | - Wenhuan Xu
- Department of Oncology, Affiliated Hospital of Jiangnan University, Wuxi, China, 214062
| | - Fengming Wang
- Blood Center of Changzhou City, Changzhou, China, 213000
| | - Dong Hua
- Department of Oncology, Affiliated Hospital of Jiangnan University, Wuxi, China, 214062
| | - Xiaowei Qi
- Department of Pathology, Affiliated Hospital of Jiangnan University, Wuxi, China, 214062.
| | - Yong Mao
- Department of Oncology, Affiliated Hospital of Jiangnan University, Wuxi, China, 214062.
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McKillop AM, Stevenson CL, Moran BM, Abdel-Wahab YHA, Flatt PR. Tissue expression of DPP-IV in obesity-diabetes and modulatory effects on peptide regulation of insulin secretion. Peptides 2018; 100:165-172. [PMID: 29412816 DOI: 10.1016/j.peptides.2017.12.020] [Citation(s) in RCA: 13] [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: 11/03/2017] [Revised: 12/18/2017] [Accepted: 12/20/2017] [Indexed: 02/01/2023]
Abstract
Dipeptidyl peptidase type 4 (DPP-4) inhibitors represent an important class of glucose-lowering drug for type 2 diabetes. DPP-4 enzyme activity has been observed to be significantly altered in type 2 diabetes. Here, the role of DPP-4 was examined in a high fat fed (HFF) mouse model of insulin resistance. HFF mice had an increased bodyweight (p < .01), were hyperglycaemic (p < .01) and hyperinsulinaemic (p < .05). Compared to normal diet, HFF mice exhibited increased plasma DPP-4 activity (p < .01). Tissue distribution patterns in lean and HFF mice demonstrated highest levels of DPP-4 activity in lung (20-26 μmol/min/mg protein) and small intestine (13-14 μmol/min/mg protein), and lowest activity in the spleen (3.8 μmol/min/mg protein). Modulation of DPP-4 activity by high fat feeding was observed in several tissues with increases in the lung (p < .05), liver (p < .05), kidney (p < .05) and pancreas (p < .05). With a high fat diet, DPP-4 gene expression was upregulated in the liver (p < .001) and downregulated in the pancreas (p < 0.001) and small intestine (p < .001). Immunohistochemical analysis revealed increased DPP-4 immunostaining localised primarily in the pancreatic islets of HFF mice (p < .01) with no change in islet GLP-1 expression. Treatment of HFF mice with metformin for 21-days resulted in inhibition of circulating DPP-4 activity (p < .05), decreased blood glucose (p < .05) and increased GLP-1 gene expression (p < .001). These data indicate that DPP-4 is modulated in a tissue specific manner and is dependent on physiological conditions such as hyperglycaemia and insulin resistance, suggesting a significant role in disorders such as diabetes.
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Affiliation(s)
- Aine M McKillop
- SAAD Centre for Pharmacy & Diabetes, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, United Kingdom.
| | - Claire L Stevenson
- SAAD Centre for Pharmacy & Diabetes, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, United Kingdom
| | - Brian M Moran
- Department of Biopharmaceutical and Medical Science, School of Science and Computing, Galway-Mayo Institute of Technology, Galway, Ireland
| | - Yasser H A Abdel-Wahab
- SAAD Centre for Pharmacy & Diabetes, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, United Kingdom
| | - Peter R Flatt
- SAAD Centre for Pharmacy & Diabetes, School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, Northern Ireland, United Kingdom
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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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Khan D, Moffet CR, Flatt PR, Kelly C. Role of islet peptides in beta cell regulation and type 2 diabetes therapy. Peptides 2018; 100:212-218. [PMID: 29412821 DOI: 10.1016/j.peptides.2017.11.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 11/22/2017] [Accepted: 11/22/2017] [Indexed: 12/25/2022]
Abstract
The endocrine pancreas is composed of islets of Langerhans, which secrete a variety of peptide hormones critical for the maintenance of glucose homeostasis. Insulin is the primary regulator of glucose and its secretion from beta-cells is tightly regulated in response to physiological demands. Direct cell-cell communication within islets is essential for glucose-induced insulin secretion. Emerging data suggest that islet connectivity is also important in the regulating the release of other islet hormones including glucagon and somatostatin. Autocrine and paracrine signals exerted by secreted peptides within the islet also play a key role. A great deal of attention has focused on classical islet peptides, namely insulin, glucagon and somatostatin. Recently, it has become clear that islets also synthesise and secrete a range of non-classical peptides, which regulate beta-cell function and insulin release. The current review summarises the roles of islet cell connectivity and islet peptide-driven autocrine and paracrine signalling in beta-cell function and survival. The potential to harness the paracrine effects of non-classical islet peptides for the treatment of type 2 diabetes is also briefly discussed.
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Affiliation(s)
- Dawood Khan
- Northern Ireland Centre for Stratified Medicine, Biomedical Sciences Research Institute, University of Ulster, C-TRIC Building, Altnagelvin Area Hospital, Glenshane Road, L/Derry, BT47 6SB, Northern Ireland, UK
| | - Charlotte R Moffet
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK
| | - Catriona Kelly
- Northern Ireland Centre for Stratified Medicine, Biomedical Sciences Research Institute, University of Ulster, C-TRIC Building, Altnagelvin Area Hospital, Glenshane Road, L/Derry, BT47 6SB, Northern Ireland, UK.
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Mohan S, Khan D, Moffett RC, Irwin N, Flatt PR. Oxytocin is present in islets and plays a role in beta-cell function and survival. Peptides 2018; 100:260-268. [PMID: 29274352 DOI: 10.1016/j.peptides.2017.12.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 12/11/2017] [Accepted: 12/19/2017] [Indexed: 01/18/2023]
Abstract
Oxytocin is associated mainly with modulating reproductive function. However, studies suggest that oxytocin also plays a role in endocrine pancreatic function. In the present study, islet expression of oxytocin and its related receptor was confirmed in mouse islets as well as cultured rodent and human beta-cells. Oxytocin significantly stimulated glucose-induced insulin secretion from isolated mouse islets. Similar insulinotropic actions were also observed in rodent BRIN BD11 and human 1.1B4 beta-cells. Positive effects of oxytocin on insulin secretion were almost fully annulled by the oxytocin receptor antagonist, atosiban. In terms of mechanism of insulin secretory action, oxytocin had no effect on beta-cell membrane potential or cAMP generation, but did augment intracellular calcium concentrations. In vivo administration of oxytocin to mice significantly reduced overall blood glucose levels and increased plasma insulin concentrations in response to a glucose challenge. Oxytocin also had a modest, but significant, appetite suppressive effect. As expected, streptozotocin diabetic mice had marked loss of beta-cell area accompanied by increases in alpha-cell area, whilst hydrocortisone treatment increased beta-cell and overall islet areas. Both mouse models of diabetes presented with dramatically decreased percentage islet oxytocin co-localisation with insulin and increased co-localisation with glucagon. More detailed studies in cultured beta-cell lines revealed direct positive effects of oxytocin on beta-cell proliferation and protection against apoptosis. Together, these data highlight a potentially important role of islet-derived oxytocin and related receptor signalling pathways on the modulation of beta-cell function and survival.
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Affiliation(s)
- Shruti Mohan
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Dawood Khan
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - R Charlotte Moffett
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK.
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
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Abstract
Type 1 diabetes is characterized by selective loss of beta cells and insulin secretion, which significantly impact glucose homeostasis. However, this progressive disease is also associated with dysfunction of the alpha cell component of the islet, which can exacerbate hyperglycemia due to paradoxical hyperglucagonemia or lead to severe hypoglycemia as a result of failed counterregulation. In this review, the physiology of alpha cell secretion and the potential mechanisms underlying alpha cell dysfunction in type 1 diabetes will be explored. Because type 1 diabetes is a progressive disease, a synthesized timeline of aberrant alpha cell function will be presented as an attempt to delineate the natural history of type 1 diabetes with respect to the alpha cell.
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Affiliation(s)
- Gina L C Yosten
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Saint Louis, MO 63104, United States.
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Hasib A, Ng MT, Khan D, Gault VA, Flatt PR, Irwin N. A novel GLP-1/xenin hybrid peptide improves glucose homeostasis, circulating lipids and restores GIP sensitivity in high fat fed mice. Peptides 2018; 100:202-211. [PMID: 29412820 DOI: 10.1016/j.peptides.2017.10.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 10/24/2017] [Accepted: 10/24/2017] [Indexed: 02/08/2023]
Abstract
Combined modulation of peptide hormone receptors including, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and xenin, have established benefits for the treatment of diabetes. The present study has assessed the biological actions and therapeutic efficacy of a novel exendin-4/xenin-8-Gln hybrid peptide, both alone and in combination with the GIP receptor agonist (DAla2)GIP. Exendin-4/xenin-8-Gln was enzymatically stable and exhibited enhanced insulin secretory actions when compared to its parent peptides. Exendin-4/xenin-8-Gln also possessed ability to potentiate the in vitro actions of GIP. Acute administration of exendin-4/xenin-8-Gln in mice induced appetite suppressive effects, as well as significant and protracted glucose-lowering and insulin secretory actions. Twice daily administration of exendin-4/xenin-8-Gln, alone or in combination with (DAla2)GIP, for 21-days significantly reduced non-fasting glucose and increased circulating insulin levels in high fat fed mice. In addition, all exendin-4/xenin-8-Gln treated mice displayed improved glucose tolerance, insulin sensitivity and metabolic responses to GIP. Combination therapy with (DAla2)GIP did not result in any obvious further benefits. Metabolic improvements in all treatment groups were accompanied by reduced pancreatic beta-cell area and insulin content, suggesting reduced insulin demand. Interestingly, body weight, food intake, circulating glucagon, metabolic rate and amylase activity were unaltered by the treatment regimens. However, all treatment groups, barring (DAla2)GIP alone, exhibited marked reductions in total- and LDL-cholesterol. Furthermore, exendin-4 therapy also reduced circulating triacylglycerol. This study highlights the positive antidiabetic effects of exendin-4/xenin-8-Gln, and suggests that combined modulation of GLP-1 and xenin related signalling pathways represents an exciting treatment option for type 2 diabetes.
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Affiliation(s)
- Annie Hasib
- From the SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Ming T Ng
- From the SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Dawood Khan
- From the SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Victor A Gault
- From the SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- From the SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- From the SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, Northern Ireland, UK.
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Paternoster S, Falasca M. Dissecting the Physiology and Pathophysiology of Glucagon-Like Peptide-1. Front Endocrinol (Lausanne) 2018; 9:584. [PMID: 30364192 PMCID: PMC6193070 DOI: 10.3389/fendo.2018.00584] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 09/14/2018] [Indexed: 12/11/2022] Open
Abstract
An aging world population exposed to a sedentary life style is currently plagued by chronic metabolic diseases, such as type-2 diabetes, that are spreading worldwide at an unprecedented rate. One of the most promising pharmacological approaches for the management of type 2 diabetes takes advantage of the peptide hormone glucagon-like peptide-1 (GLP-1) under the form of protease resistant mimetics, and DPP-IV inhibitors. Despite the improved quality of life, long-term treatments with these new classes of drugs are riddled with serious and life-threatening side-effects, with no overall cure of the disease. New evidence is shedding more light over the complex physiology of GLP-1 in health and metabolic diseases. Herein, we discuss the most recent advancements in the biology of gut receptors known to induce the secretion of GLP-1, to bridge the multiple gaps into our understanding of its physiology and pathology.
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