1
|
Peart LA, Draper M, Tarasov AI. The impact of GLP-1 signalling on the energy metabolism of pancreatic islet β-cells and extrapancreatic tissues. Peptides 2024; 178:171243. [PMID: 38788902 DOI: 10.1016/j.peptides.2024.171243] [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: 03/27/2024] [Revised: 05/19/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024]
Abstract
Glucagon-like peptide-1 signalling impacts glucose homeostasis and appetite thereby indirectly affecting substrate availability at the whole-body level. The incretin canonically produces an insulinotropic effect, thereby lowering blood glucose levels by promoting the uptake and inhibiting the production of the sugar by peripheral tissues. Likewise, GLP-1 signalling within the central nervous system reduces the appetite and food intake, whereas its gastric effect delays the absorption of nutrients, thus improving glycaemic control and reducing the risk of postprandial hyperglycaemia. We review the molecular aspects of the GLP-1 signalling, focusing on its impact on intracellular energy metabolism. Whilst the incretin exerts its effects predominantly via a Gs receptor, which decodes the incretin signal into the elevation of intracellular cAMP levels, the downstream signalling cascades within the cell, acting on fast and slow timescales, resulting in an enhancement or an attenuation of glucose catabolism, respectively.
Collapse
Affiliation(s)
- Leah A Peart
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Northern Ireland BT52 1SA, UK
| | - Matthew Draper
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Northern Ireland BT52 1SA, UK
| | - Andrei I Tarasov
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Northern Ireland BT52 1SA, UK.
| |
Collapse
|
2
|
Acreman S, Ma J, Denwood G, Gao R, Tarasov A, Rorsman P, Zhang Q. The endoplasmic reticulum plays a key role in α-cell intracellular Ca 2+ dynamics and glucose-regulated glucagon secretion in mouse islets. iScience 2024; 27:109665. [PMID: 38646167 PMCID: PMC11033163 DOI: 10.1016/j.isci.2024.109665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 02/13/2024] [Accepted: 04/02/2024] [Indexed: 04/23/2024] Open
Abstract
Glucagon is secreted by pancreatic α-cells to counteract hypoglycaemia. How glucose regulates glucagon secretion remains unclear. Here, using mouse islets, we studied the role of transmembrane and endoplasmic reticulum (ER) Ca2+ on intrinsic α-cell glucagon secretion. Blocking isradipine-sensitive L-type voltage-gated Ca2+ (Cav) channels abolished α-cell electrical activity but had little impact on its cytosolic Ca2+ oscillations or low-glucose-stimulated glucagon secretion. In contrast, depleting ER Ca2+ with cyclopiazonic acid or blocking ER Ca2+-releasing ryanodine receptors abolished α-cell glucose sensitivity and low-glucose-stimulated glucagon secretion. ER Ca2+ mobilization in α-cells is regulated by intracellular ATP and likely to be coupled to Ca2+ influx through P/Q-type Cav channels. ω-Agatoxin IVA blocked α-cell ER Ca2+ release and cell exocytosis, but had no additive effect on glucagon secretion when combined with ryanodine. We conclude that glucose regulates glucagon secretion through the control of ER Ca2+ mobilization, a mechanism that can be independent of α-cell electrical activity.
Collapse
Affiliation(s)
- Samuel Acreman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
- Institute of Neuroscience and Physiology, Department of Physiology, Metabolic Research Unit, Sahlgrenska Academy, University of Gothenburg, Box 430, S-405 30 Gothenburg, Sweden
| | - Jinfang Ma
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
- Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, China
| | - Geoffrey Denwood
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
| | - Rui Gao
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
| | - Andrei Tarasov
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
- Institute of Neuroscience and Physiology, Department of Physiology, Metabolic Research Unit, Sahlgrenska Academy, University of Gothenburg, Box 430, S-405 30 Gothenburg, Sweden
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Quan Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
- CNC - Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, Portugal
| |
Collapse
|
3
|
Turbitt J, Moffett RC, Brennan L, Johnson PRV, Flatt PR, McClenaghan NH, Tarasov AI. Molecular determinants and intracellular targets of taurine signalling in pancreatic islet β-cells. Acta Physiol (Oxf) 2024; 240:e14101. [PMID: 38243723 DOI: 10.1111/apha.14101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 12/26/2023] [Accepted: 01/08/2024] [Indexed: 01/21/2024]
Abstract
AIM Despite its abundance in pancreatic islets of Langerhans and proven antihyperglycemic effects, the impact of the essential amino acid, taurine, on islet β-cell biology has not yet received due consideration, which prompted the current studies exploring the molecular selectivity of taurine import into β-cells and its acute and chronic intracellular interactions. METHODS The molecular aspects of taurine transport were probed by exposing the clonal pancreatic BRIN BD11 β-cells and primary mouse and human islets to a range of the homologs of the amino acid (assayed at 2-20 mM), using the hormone release and imaging of intracellular signals as surrogate read-outs. Known secretagogues were employed to profile the interaction of taurine with acute and chronic intracellular signals. RESULTS Taurine transporter TauT was expressed in the islet β-cells, with the transport of taurine and homologs having a weak sulfonate specificity but significant sensitivity to the molecular weight of the transporter. Taurine, hypotaurine, homotaurine, and β-alanine enhanced insulin secretion in a glucose-dependent manner, an action potentiated by cytosolic Ca2+ and cAMP. Acute and chronic β-cell insulinotropic effects of taurine were highly sensitive to co-agonism with GLP-1, forskolin, tolbutamide, and membrane depolarization, with an unanticipated indifference to the activation of PKC and CCK8 receptors. Pre-culturing with GLP-1 or KATP channel inhibitors sensitized or, respectively, desensitized β-cells to the acute taurine stimulus. CONCLUSION Together, these data demonstrate the pathways whereby taurine exhibits a range of beneficial effects on insulin secretion and β-cell function, consistent with the antidiabetic potential of its dietary low-dose supplementation.
Collapse
Affiliation(s)
- Julie Turbitt
- School of Biomedical Sciences, Ulster University, Coleraine, UK
| | | | - Lorraine Brennan
- UCD Institute of Food and Health, UCD School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland
- UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Republic of Ireland
| | - Paul R V Johnson
- Nuffield Department of Surgical Sciences, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- Oxford Biomedical Research Centre (OxBRC), 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, Republic of Ireland
| | | |
Collapse
|
4
|
Turbitt J, Brennan L, Moffett RC, Flatt PR, Johnson PRV, Tarasov AI, McClenaghan NH. NKCC transport mediates the insulinotropic effects of taurine and other small neutral amino acids. Life Sci 2023; 316:121402. [PMID: 36669678 DOI: 10.1016/j.lfs.2023.121402] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 01/04/2023] [Accepted: 01/13/2023] [Indexed: 01/19/2023]
Abstract
AIMS Despite its high concentration in pancreatic islets of Langerhans and broad range of antihyperglycemic effects, the route facilitating the import of dietary taurine into pancreatic β-cell and mechanisms underlying its insulinotropic activity are unclear. We therefore studied the impact of taurine on beta-cell function, alongside that of other small neutral amino acids, L-alanine and L-proline. MAIN METHODS Pharmacological profiling of insulin secretion was conducted using clonal BRIN BD11 β-cells, the impact of taurine on the metabolic fate of glucose carbons was assessed using NMR and the findings were verified by real-time imaging of Ca2+ dynamics in the cytosol of primary mouse and human islet beta-cells. KEY FINDINGS In our hands, taurine, alanine and proline induced secretory responses that were dependent on the plasma membrane depolarisation, import of Ca2+, homeostasis of K+ and Na+ as well as on cell glycolytic and oxidative metabolism. Taurine shifted the balance between the oxidation and anaplerosis towards the latter, in BRIN BD11 beta-cells. Furthermore, the amino acid signalling was significantly attenuated by inhibition of Na+-K+-Cl- symporter (NKCC). SIGNIFICANCE These data suggest that taurine, like L-alanine and L-proline, acutely induces glucose-dependent insulin-secretory responses by modulating electrogenic Na+ transport, with potential role of intracellular K+ and Cl- in the signal transduction. The acute action delineated would be consistent with antidiabetic potential of dietary taurine supplementation.
Collapse
Affiliation(s)
- Julie Turbitt
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine BT52 1SA, UK
| | - Lorraine Brennan
- UCD Institute of Food and Health, UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland; UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
| | - R Charlotte Moffett
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine BT52 1SA, UK.
| | - Peter R Flatt
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine BT52 1SA, UK.
| | - Paul R V Johnson
- Nuffeld Department of Surgical Sciences, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Headington, OX3 7LE Oxford, UK; Oxford Biomedical Research Centre (OxBRC), UK.
| | - Andrei I Tarasov
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine BT52 1SA, UK; Nuffeld Department of Surgical Sciences, Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Headington, OX3 7LE Oxford, UK; Oxford Biomedical Research Centre (OxBRC), UK.
| | - Neville H McClenaghan
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine BT52 1SA, UK; Department of Life Sciences, Atlantic Technological University, Ash Lane, Sligo, F91 YW50, Ireland.
| |
Collapse
|
5
|
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: 4] [Impact Index Per Article: 4.0] [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.
Collapse
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
| | | |
Collapse
|
6
|
Zois CE, Hendriks AM, Haider S, Pires E, Bridges E, Kalamida D, Voukantsis D, Lagerholm BC, Fehrmann RSN, den Dunnen WFA, Tarasov AI, Baba O, Morris J, Buffa FM, McCullagh JSO, Jalving M, Harris AL. Liver glycogen phosphorylase is upregulated in glioblastoma and provides a metabolic vulnerability to high dose radiation. Cell Death Dis 2022; 13:573. [PMID: 35764612 PMCID: PMC9240045 DOI: 10.1038/s41419-022-05005-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 05/16/2022] [Accepted: 06/08/2022] [Indexed: 01/21/2023]
Abstract
Channelling of glucose via glycogen, known as the glycogen shunt, may play an important role in the metabolism of brain tumours, especially in hypoxic conditions. We aimed to dissect the role of glycogen degradation in glioblastoma (GBM) response to ionising radiation (IR). Knockdown of the glycogen phosphorylase liver isoform (PYGL), but not the brain isoform (PYGB), decreased clonogenic growth and survival of GBM cell lines and sensitised them to IR doses of 10-12 Gy. Two to five days after IR exposure of PYGL knockdown GBM cells, mitotic catastrophy and a giant multinucleated cell morphology with senescence-like phenotype developed. The basal levels of the lysosomal enzyme alpha-acid glucosidase (GAA), essential for autolysosomal glycogen degradation, and the lipidated forms of gamma-aminobutyric acid receptor-associated protein-like (GABARAPL1 and GABARAPL2) increased in shPYGL U87MG cells, suggesting a compensatory mechanism of glycogen degradation. In response to IR, dysregulation of autophagy was shown by accumulation of the p62 and the lipidated form of GABARAPL1 and GABARAPL2 in shPYGL U87MG cells. IR increased the mitochondrial mass and the colocalisation of mitochondria with lysosomes in shPYGL cells, thereby indicating reduced mitophagy. These changes coincided with increased phosphorylation of AMP-activated protein kinase and acetyl-CoA carboxylase 2, slower ATP generation in response to glucose loading and progressive loss of oxidative phosphorylation. The resulting metabolic deficiencies affected the availability of ATP required for mitosis, resulting in the mitotic catastrophy observed in shPYGL cells following IR. PYGL mRNA and protein levels were higher in human GBM than in normal human brain tissues and high PYGL mRNA expression in GBM correlated with poor patient survival. In conclusion, we show a major new role for glycogen metabolism in GBM cancer. Inhibition of glycogen degradation sensitises GBM cells to high-dose IR indicating that PYGL is a potential novel target for the treatment of GBMs.
Collapse
Affiliation(s)
- Christos E Zois
- Molecular Oncology Laboratories, Department of Oncology, Oxford University, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK.
| | - Anne M Hendriks
- Molecular Oncology Laboratories, Department of Oncology, Oxford University, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK
- Department of Medical Oncology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - Syed Haider
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | | | - Esther Bridges
- Molecular Oncology Laboratories, Department of Oncology, Oxford University, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK
| | - Dimitra Kalamida
- Department of Oncology, Democritus University of Thrace, Alexandroupolis, Greece
| | - Dimitrios Voukantsis
- The Bioinformatics Hub, Department of Oncology, University of Oxford, Oxford, UK
| | | | - Rudolf S N Fehrmann
- Department of Medical Oncology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - Wilfred F A den Dunnen
- Department of Pathology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - Andrei I Tarasov
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Otto Baba
- Tokushima University Graduate School, Tokushima, Japan
| | - John Morris
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Francesca M Buffa
- Department of Oncology, University of Oxford, Churchill Hospital, Oxford, UK
| | | | - Mathilde Jalving
- Department of Medical Oncology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | - Adrian L Harris
- Molecular Oncology Laboratories, Department of Oncology, Oxford University, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK.
| |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
San Martín A, Arce-Molina R, Aburto C, Baeza-Lehnert F, Barros LF, Contreras-Baeza Y, Pinilla A, Ruminot I, Rauseo D, Sandoval PY. Visualizing physiological parameters in cells and tissues using genetically encoded indicators for metabolites. Free Radic Biol Med 2022; 182:34-58. [PMID: 35183660 DOI: 10.1016/j.freeradbiomed.2022.02.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 02/07/2023]
Abstract
The study of metabolism is undergoing a renaissance. Since the year 2002, over 50 genetically-encoded fluorescent indicators (GEFIs) have been introduced, capable of monitoring metabolites with high spatial/temporal resolution using fluorescence microscopy. Indicators are fusion proteins that change their fluorescence upon binding a specific metabolite. There are indicators for sugars, monocarboxylates, Krebs cycle intermediates, amino acids, cofactors, and energy nucleotides. They permit monitoring relative levels, concentrations, and fluxes in living systems. At a minimum they report relative levels and, in some cases, absolute concentrations may be obtained by performing ad hoc calibration protocols. Proper data collection, processing, and interpretation are critical to take full advantage of these new tools. This review offers a survey of the metabolic indicators that have been validated in mammalian systems. Minimally invasive, these indicators have been instrumental for the purposes of confirmation, rebuttal and discovery. We envision that this powerful technology will foster metabolic physiology.
Collapse
Affiliation(s)
- A San Martín
- Centro de Estudios Científicos (CECs), Valdivia, Chile.
| | - R Arce-Molina
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - C Aburto
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | | | - L F Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - Y Contreras-Baeza
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - A Pinilla
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - I Ruminot
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - D Rauseo
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - P Y Sandoval
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| |
Collapse
|
9
|
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]
|
10
|
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.
Collapse
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.
| |
Collapse
|
11
|
Borg DJ, Faridi P, Giam KL, Reeves P, Fotheringham AK, McCarthy DA, Leung S, Ward MS, Harcourt BE, Ayala R, Scheijen JL, Briskey D, Dudek NL, Schalkwijk CG, Steptoe R, Purcell AW, Forbes JM. Short Duration Alagebrium Chloride Therapy Prediabetes Does Not Inhibit Progression to Autoimmune Diabetes in an Experimental Model. Metabolites 2021; 11:426. [PMID: 34203471 PMCID: PMC8305727 DOI: 10.3390/metabo11070426] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/21/2021] [Accepted: 06/22/2021] [Indexed: 12/17/2022] Open
Abstract
Mechanisms by which advanced glycation end products (AGEs) contribute to type 1 diabetes (T1D) pathogenesis are poorly understood. Since life-long pharmacotherapy with alagebrium chloride (ALT) slows progression to experimental T1D, we hypothesized that acute ALT therapy delivered prediabetes, may be effective. However, in female, non-obese diabetic (NODShiLt) mice, ALT administered prediabetes (day 50-100) did not protect against experimental T1D. ALT did not decrease circulating AGEs or their precursors. Despite this, pancreatic β-cell function was improved, and insulitis and pancreatic CD45.1+ cell infiltration was reduced. Lymphoid tissues were unaffected. ALT pre-treatment, prior to transfer of primed GC98 CD8+ T cell receptor transgenic T cells, reduced blood glucose concentrations and delayed diabetes, suggesting islet effects rather than immune modulation by ALT. Indeed, ALT did not reduce interferon-γ production by leukocytes from ovalbumin-pre-immunised NODShiLt mice and NODscid recipients given diabetogenic ALT treated NOD splenocytes were not protected against T1D. To elucidate β-cell effects, NOD-derived MIN6N8 β-cell major histocompatibility complex (MHC) Class Ia surface antigens were examined using immunopeptidomics. Overall, no major changes in the immunopeptidome were observed during the various treatments with all peptides exhibiting allele specific consensus binding motifs. As expected, longer MHC Class Ia peptides were captured bound to H-2Db than H-2Kb under all conditions. Moreover, more 10-12 mer peptides were isolated from H-2Db after AGE modified bovine serum albumin (AGE-BSA) treatment, compared with bovine serum albumin (BSA) or AGE-BSA+ALT treatment. Proteomics of MIN6N8 cells showed enrichment of processes associated with catabolism, the immune system, cell cycling and presynaptic endocytosis with AGE-BSA compared with BSA treatments. These data show that short-term ALT intervention, given prediabetes, does not arrest experimental T1D but transiently impacts β-cell function.
Collapse
Affiliation(s)
- Danielle J. Borg
- Glycation and Diabetes Complications, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, QLD 4102, Australia; (D.J.B.); (A.K.F.); (D.A.M.); (S.L.); (M.S.W.); (B.E.H.)
- Pregnancy and Development, Mater Research Institute, The University of Queensland, South Brisbane, QLD 4101, Australia
| | - Pouya Faridi
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia; (P.F.); (K.L.G.); (R.A.); (N.L.D.); (A.W.P.)
| | - Kai Lin Giam
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia; (P.F.); (K.L.G.); (R.A.); (N.L.D.); (A.W.P.)
| | - Peta Reeves
- Tolerance and Autoimmunity Group, The University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, QLD 4102, Australia; (P.R.); (R.S.)
| | - Amelia K. Fotheringham
- Glycation and Diabetes Complications, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, QLD 4102, Australia; (D.J.B.); (A.K.F.); (D.A.M.); (S.L.); (M.S.W.); (B.E.H.)
| | - Domenica A. McCarthy
- Glycation and Diabetes Complications, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, QLD 4102, Australia; (D.J.B.); (A.K.F.); (D.A.M.); (S.L.); (M.S.W.); (B.E.H.)
| | - Sherman Leung
- Glycation and Diabetes Complications, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, QLD 4102, Australia; (D.J.B.); (A.K.F.); (D.A.M.); (S.L.); (M.S.W.); (B.E.H.)
| | - Micheal S. Ward
- Glycation and Diabetes Complications, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, QLD 4102, Australia; (D.J.B.); (A.K.F.); (D.A.M.); (S.L.); (M.S.W.); (B.E.H.)
| | - Brooke E. Harcourt
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
| | - Rochelle Ayala
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia; (P.F.); (K.L.G.); (R.A.); (N.L.D.); (A.W.P.)
| | - Jean L. Scheijen
- Laboratory for Metabolism and Vascular Medicine, Department of Internal Medicine, Maastricht University, 6211 Maastricht, The Netherlands; (J.L.S.); (C.G.S.)
- Cardiovascular Research Institute Maastricht, 6211 Maastricht, The Netherlands
| | - David Briskey
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD 4067, Australia;
| | - Nadine L. Dudek
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia; (P.F.); (K.L.G.); (R.A.); (N.L.D.); (A.W.P.)
| | - Casper G. Schalkwijk
- Laboratory for Metabolism and Vascular Medicine, Department of Internal Medicine, Maastricht University, 6211 Maastricht, The Netherlands; (J.L.S.); (C.G.S.)
- Cardiovascular Research Institute Maastricht, 6211 Maastricht, The Netherlands
| | - Raymond Steptoe
- Tolerance and Autoimmunity Group, The University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, QLD 4102, Australia; (P.R.); (R.S.)
| | - Anthony W. Purcell
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia; (P.F.); (K.L.G.); (R.A.); (N.L.D.); (A.W.P.)
| | - Josephine M. Forbes
- Glycation and Diabetes Complications, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, QLD 4102, Australia; (D.J.B.); (A.K.F.); (D.A.M.); (S.L.); (M.S.W.); (B.E.H.)
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
- Mater Clinical School, The University of Queensland, Brisbane, QLD 4101, Australia
| |
Collapse
|
12
|
Miranda MA, Macias-Velasco JF, Lawson HA. Pancreatic β-cell heterogeneity in health and diabetes: classes, sources, and subtypes. Am J Physiol Endocrinol Metab 2021; 320:E716-E731. [PMID: 33586491 PMCID: PMC8238131 DOI: 10.1152/ajpendo.00649.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Pancreatic β-cells perform glucose-stimulated insulin secretion, a process at the center of type 2 diabetes etiology. Efforts to understand how β-cells behave in healthy and stressful conditions have revealed a wide degree of morphological, functional, and transcriptional heterogeneity. Sources of heterogeneity include β-cell topography, developmental origin, maturation state, and stress response. Advances in sequencing and imaging technologies have led to the identification of β-cell subtypes, which play distinct roles in the islet niche. This review examines β-cell heterogeneity from morphological, functional, and transcriptional perspectives, and considers the relevance of topography, maturation, development, and stress response. It also discusses how these factors have been used to identify β-cell subtypes, and how heterogeneity is impacted by diabetes. We examine open questions in the field and discuss recent technological innovations that could advance understanding of β-cell heterogeneity in health and disease.
Collapse
Affiliation(s)
- Mario A Miranda
- Department of Genetics, Washington University School of Medicine, Saint Louis, Missouri
| | - Juan F Macias-Velasco
- Department of Genetics, Washington University School of Medicine, Saint Louis, Missouri
| | - Heather A Lawson
- Department of Genetics, Washington University School of Medicine, Saint Louis, Missouri
| |
Collapse
|
13
|
Imaging Meets Cytometry: Analyzing Heterogeneous Functional Microscopic Data from Living Cell Populations. J Imaging 2021; 7:jimaging7010009. [PMID: 34460580 PMCID: PMC8321243 DOI: 10.3390/jimaging7010009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/06/2021] [Accepted: 01/09/2021] [Indexed: 12/27/2022] Open
Abstract
Biological tissue consists of populations of cells exhibiting different responses to pharmacological stimuli. To probe the heterogeneity of cell function, we propose a multiplexed approach based on real‐time imaging of the secondary messenger levels within each cell of the tissue, followed by extraction of the changes of single‐cell fluorescence over time. By utilizing a piecewise baseline correction, we were able to quantify the effects of multiple pharmacological stimuli added and removed sequentially to pancreatic islets of Langerhans, thereby performing a deep functional profiling for each cell within the islet. Cluster analysis based on the functional profile demonstrated dose‐dependent changes in statistical inter‐relationships between islet cell populations. We therefore believe that the functional cytometric approach can be used for routine quantitative profiling of the tissue for drug screening or pathological testing.
Collapse
|
14
|
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.
Collapse
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.
| |
Collapse
|
15
|
Bednarska J, Novak P, Korchev Y, Rorsman P, Tarasov AI, Shevchuk A. Release of insulin granules by simultaneous, high-speed correlative SICM-FCM. J Microsc 2020; 282:21-29. [PMID: 33089519 DOI: 10.1111/jmi.12972] [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: 07/13/2020] [Accepted: 10/19/2020] [Indexed: 11/27/2022]
Abstract
Exocytosis of peptides and steroids stored in a dense core vesicular (DCV) form is the final step of every secretory pathway, indispensable for the function of nervous, endocrine and immune systems. The lack of live imaging techniques capable of direct, label-free visualisation of DCV release makes many aspects of the exocytotic process inaccessible to investigation. We describe the application of correlative scanning ion conductance and fluorescence confocal microscopy (SICM-FCM) to study the exocytosis of individual granules of insulin from the top, nonadherent, surface of pancreatic β-cells. Using SICM-FCM, we were first to directly follow the topographical changes associated with physiologically induced release of insulin DCVs. This allowed us to report the kinetics of the full fusion of the insulin vesicle as well as the subsequent solubilisation of the released insulin crystal.
Collapse
Affiliation(s)
- J Bednarska
- Department of Medicine, Imperial College London, London, U.K
| | - P Novak
- Department of Medicine, Imperial College London, London, U.K.,National University of Science and Technology 'MISIS', Moscow, Russian Federation
| | - Y Korchev
- Department of Medicine, Imperial College London, London, U.K.,Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, Japan
| | - P Rorsman
- OCDEM, Radcliffe Department of Medicine, University of Oxford, Oxford, U.K
| | - A I Tarasov
- OCDEM, Radcliffe Department of Medicine, University of Oxford, Oxford, U.K.,School of Biomedical Sciences, Ulster University, Coleraine, U.K
| | - Andrew Shevchuk
- Department of Medicine, Imperial College London, London, U.K
| |
Collapse
|
16
|
Abstract
Controlling the excess and shortage of energy is a fundamental task for living organisms. Diabetes is a representative metabolic disease caused by the malfunction of energy homeostasis. The islets of Langerhans in the pancreas release long-range messengers, hormones, into the blood to regulate the homeostasis of the primary energy fuel, glucose. The hormone and glucose levels in the blood show rhythmic oscillations with a characteristic period of 5-10 min, and the functional roles of the oscillations are not clear. Each islet has [Formula: see text] and [Formula: see text] cells that secrete glucagon and insulin, respectively. These two counter-regulatory hormones appear sufficient to increase and decrease glucose levels. However, pancreatic islets have a third cell type, [Formula: see text] cells, which secrete somatostatin. The three cell populations have a unique spatial organization in islets, and they interact to perturb their hormone secretions. The mini-organs of islets are scattered throughout the exocrine pancreas. Considering that the human pancreas contains approximately a million islets, the coordination of hormone secretion from the multiple sources of islets and cells within the islets should have a significant effect on human physiology. In this review, we introduce the hierarchical organization of tripartite cell networks, and recent biophysical modeling to systematically understand the oscillations and interactions of [Formula: see text], [Formula: see text], and [Formula: see text] cells. Furthermore, we discuss the functional roles and clinical implications of hormonal oscillations and their phase coordination for the diagnosis of type II diabetes.
Collapse
Affiliation(s)
- Taegeun Song
- Department of Physics, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea
| | | |
Collapse
|