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Chen T, Yu J, Guo X, Wang S, Wang Z, Chen Y, Hu X, Li H, Chen L, Zheng J. Adenosine kinase inhibits β-cell proliferation by upregulating DNA methyltransferase 3A expression. Diabetes Obes Metab 2024; 26:2956-2968. [PMID: 38699782 DOI: 10.1111/dom.15621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 03/31/2024] [Accepted: 04/06/2024] [Indexed: 05/05/2024]
Abstract
AIM To investigate the effects of adenosine kinase (ADK), a key enzyme in determining intracellular adenosine levels, on β cells, and their underlying mechanism. METHODS Genetic animal models and transgenic immortalized cells were applied to study the effect of ADK on islet beta-cell proliferation and function. The beta-cell mass and response to glucose were measured in vivo using mice with beta-cell-specific ADK overexpression, and in vitro using ADK-overexpressed immortalized beta-cell. RESULTS The expression of ADK in human islets at high abundance, especially in β cells, was decreased during the process of β-cell proliferation. Additionally, a transgenic mouse model (ADKtg/tg /Mip-Cre) was generated wherein the mouse Insulin1 gene promoter specifically overexpressed ADK in pancreatic β cells. The ADKtg/tg /Mip-Cre model exhibited impaired glucose tolerance, decreased fasting plasma insulin, loss of β-cell mass, and inhibited β-cell proliferation. Proteomic analysis revealed that ADK overexpression inhibited the expression of several proteins that promote cell proliferation and insulin secretion. Upregulating ADK in the β-cell line inhibited the expression of β-cell related regulatory molecules, including FoxO1, Appl1, Pxn, Pdx-1, Creb and Slc16a3. Subsequent in vitro experiments indicated that the inhibition of β-cell proliferation and the decreased expression of Pdx-1, Creb and Slc16a3 were rescued by DNA methyltransferase 3A (DNMT3A) knockdown in β cells. CONCLUSION In this study, we found that the overexpression of ADK decreased the expression of several genes that regulate β cells, resulting in the inhibition of β-cell proliferation and dysfunction by upregulating the expression of DNMT3A.
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Affiliation(s)
- Ting Chen
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China
| | - Jiayu Yu
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China
| | - Xin Guo
- Department of Nutrition and Food Hygiene, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Siqi Wang
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China
| | - Zhihua Wang
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China
| | - Yang Chen
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China
| | - Xiang Hu
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China
| | - Huiqing Li
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China
| | - Lulu Chen
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China
| | - Juan Zheng
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China
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2
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Pan X, Tao S, Tong N. Potential Therapeutic Targeting Neurotransmitter Receptors in Diabetes. Front Endocrinol (Lausanne) 2022; 13:884549. [PMID: 35669692 PMCID: PMC9163348 DOI: 10.3389/fendo.2022.884549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 04/19/2022] [Indexed: 12/04/2022] Open
Abstract
Neurotransmitters are signaling molecules secreted by neurons to coordinate communication and proper function among different sections in the central neural system (CNS) by binding with different receptors. Some neurotransmitters as well as their receptors are found in pancreatic islets and are involved in the regulation of glucose homeostasis. Neurotransmitters can act with their receptors in pancreatic islets to stimulate or inhibit the secretion of insulin (β cell), glucagon (α cell) or somatostatin (δ cell). Neurotransmitter receptors are either G-protein coupled receptors or ligand-gated channels, their effects on blood glucose are mainly decided by the number and location of them in islets. Dysfunction of neurotransmitters receptors in islets is involved in the development of β cell dysfunction and type 2 diabetes (T2D).Therapies targeting different transmitter systems have great potential in the prevention and treatment of T2D and other metabolic diseases.
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Affiliation(s)
- Xiaohui Pan
- Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, China
- Laboratory of Diabetes and Islet Transplantation, Center for Diabetes and Metabolism Research, West China Hospital, Sichuan University, Chengdu, China
| | - Shibing Tao
- Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, China
- Department of Endocrinology, Ziyang First People’s Hospital, Ziyang, China
| | - Nanwei Tong
- Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, China
- Laboratory of Diabetes and Islet Transplantation, Center for Diabetes and Metabolism Research, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Nanwei Tong,
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Somatostatin and Its Receptor System in Colorectal Cancer. Biomedicines 2021; 9:biomedicines9111743. [PMID: 34829972 PMCID: PMC8615525 DOI: 10.3390/biomedicines9111743] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/19/2021] [Accepted: 11/20/2021] [Indexed: 12/14/2022] Open
Abstract
Somatostatin (SST)/somatotropin release-inhibiting factor (SRIF) is a well-known neuropeptide, widely distributed in the central and peripheral nervous systems, that regulates the endocrine system and affects neurotransmission via interaction with five SST receptors (SST1-5). In the gastrointestinal tract, the main SST-producing cells include intestinal enteroendocrine cells (EECs) restricted to the mucosa, and neurons of the submucosal and myenteric plexuses. The action of the SRIF system is based on the inhibition of endocrine and exocrine secretion, as well as the proliferative responses of target cells. The SST1–5 share common signaling pathways, and are not only widely expressed on normal tissues, but also frequently overexpressed by several tumors, particularly neuroendocrine neoplasms (NENs). Furthermore, the SRIF system represents the only peptide/G protein-coupled receptor (GPCR) system with multiple approved clinical applications for the diagnosis and treatment of several NENs. The role of the SRIF system in the histogenesis of colorectal cancer (CRC) subtypes (e.g., adenocarcinoma and signet ring-cell carcinoma), as well as diagnosis and prognosis of mixed adenoneuroendocrine carcinoma (MANEC) and pure adenocarcinoma, is poorly understood. Moreover, the impact of the SRIF system signaling on CRC cell proliferation and its potential role in the progression of this cancer remains unknown. Therefore, this review summarizes the recent collective knowledge and understanding of the clinical significance of the SRIF system signaling in CRC, aiming to evaluate the potential role of its components in CRC histogenesis, diagnosis, and potential therapy.
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4
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Jain S, Jacobson KA. Purinergic signaling in diabetes and metabolism. Biochem Pharmacol 2020; 187:114393. [PMID: 33359363 DOI: 10.1016/j.bcp.2020.114393] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/22/2022]
Abstract
Purinergic signaling, a concept originally formulated by the late Geoffrey Burnstock (1929-2020), was found to modulate pathways in every physiological system. In metabolic disorders there is a role for both adenosine receptors and P2 (nucleotide) receptors, of which there are two classes, i.e. P2Y metabotropic and P2X ionotropic receptors. The individual roles of the 19 receptors encompassed by this family have been dissected - and in many cases the effects associated with specific cell types, including adipocytes, skeletal muscle, liver cells and immune cells. It is suggested that ligands selective for each of the four adenosine receptors (A1, A2A, A2B and A3), and several of the P2 subtypes (e.g. P2Y6 or P2X7 antagonists) might have therapeutic potential for treating diabetes and obesity. This is a developing story with some conflicting conclusions relevant to drug discovery, which we summarize here.
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Affiliation(s)
- Shanu Jain
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
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Parandeh F, Amisten S, Verma G, Mohammed Al-Amily I, Dunér P, Salehi A. Inhibitory effect of UDP-glucose on cAMP generation and insulin secretion. J Biol Chem 2020; 295:15245-15252. [PMID: 32855238 DOI: 10.1074/jbc.ra120.012929] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 08/21/2020] [Indexed: 12/27/2022] Open
Abstract
Type-2 diabetes (T2D) is a global disease caused by the inability of pancreatic β-cells to secrete adequate insulin. However, the molecular mechanisms underlying the failure of β-cells to respond to glucose in T2D remains unknown. Here, we investigated the relative contribution of UDP-glucose (UDP-G), a P2Y14-specific agonist, in the regulation of insulin release using human isolated pancreatic islets and INS-1 cells. P2Y14 was expressed in both human and rodent pancreatic β-cells. Dose-dependent activation of P2Y14 by UDP-G suppressed glucose-stimulated insulin secretion (GSIS) and knockdown of P2Y14 abolished the UDP-G effect. 12-h pretreatment of human islets with pertussis-toxin (PTX) improved GSIS and prevented the inhibitory effect of UDP-G on GSIS. UDP-G on GSIS suppression was associated with suppression of cAMP in INS-1 cells. UDP-G decreased the reductive capacity of nondiabetic human islets cultured at 5 mm glucose for 72 h and exacerbated the negative effect of 20 mm glucose on the cell viability during culture period. T2D donor islets displayed a lower reductive capacity when cultured at 5 mm glucose for 72 h that was further decreased in the presence of 20 mm glucose and UDP-G. Presence of a nonmetabolizable cAMP analog during culture period counteracted the effect of glucose and UDP-G. Islet cultures at 20 mm glucose increased apoptosis, which was further amplified when UDP-G was present. UDP-G modulated glucose-induced proliferation of INS-1 cells. The data provide intriguing evidence for P2Y14 and UDP-G's role in the regulation of pancreatic β-cell function.
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Affiliation(s)
- Fariborz Parandeh
- Department of Clinical Science, Division of Islet Cell Physiology, UMAS University of Lund, Malmö, Sweden
| | - Stefan Amisten
- Department of Clinical Science, Division of Islet Cell Physiology, UMAS University of Lund, Malmö, Sweden
| | - Gaurav Verma
- Department of Clinical Science, Division of Islet Cell Physiology, UMAS University of Lund, Malmö, Sweden
| | - Israa Mohammed Al-Amily
- Department of Clinical Science, Division of Islet Cell Physiology, UMAS University of Lund, Malmö, Sweden
| | - Pontus Dunér
- Experimental Cardiovascular Research Unit Clinical Research Centre, UMAS University of Lund, Malmö, Sweden
| | - Albert Salehi
- Department of Clinical Science, Division of Islet Cell Physiology, UMAS University of Lund, Malmö, Sweden.
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6
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Duarte JMN, Skoug C, Silva HB, Carvalho RA, Gruetter R, Cunha RA. Impact of Caffeine Consumption on Type 2 Diabetes-Induced Spatial Memory Impairment and Neurochemical Alterations in the Hippocampus. Front Neurosci 2019; 12:1015. [PMID: 30686981 PMCID: PMC6333904 DOI: 10.3389/fnins.2018.01015] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 12/17/2018] [Indexed: 12/20/2022] Open
Abstract
Diabetes affects the morphology and plasticity of the hippocampus, and leads to learning and memory deficits. Caffeine has been proposed to prevent memory impairment upon multiple chronic disorders with neurological involvement. We tested whether long-term caffeine consumption prevents type 2 diabetes (T2D)-induced spatial memory impairment and hippocampal alterations, including synaptic degeneration, astrogliosis, and metabolic modifications. Control Wistar rats and Goto-Kakizaki (GK) rats that develop T2D were treated with caffeine (1 g/L in drinking water) for 4 months. Spatial memory was evaluated in a Y-maze. Hippocampal metabolic profile and glucose homeostasis were investigated by 1H magnetic resonance spectroscopy. The density of neuronal, synaptic, and glial-specific markers was evaluated by Western blot analysis. GK rats displayed reduced Y-maze spontaneous alternation and a lower amplitude of hippocampal long-term potentiation when compared to controls, suggesting impaired hippocampal-dependent spatial memory. Diabetes did not impact the relation of hippocampal to plasma glucose concentrations, but altered the neurochemical profile of the hippocampus, such as increased in levels of the osmolites taurine (P < 0.001) and myo-inositol (P < 0.05). The diabetic hippocampus showed decreased density of the presynaptic proteins synaptophysin (P < 0.05) and SNAP25 (P < 0.05), suggesting synaptic degeneration, and increased GFAP (P < 0.001) and vimentin (P < 0.05) immunoreactivities that are indicative of astrogliosis. The effects of caffeine intake on hippocampal metabolism added to those of T2D, namely reducing myo-inositol levels (P < 0.001) and further increasing taurine levels (P < 0.05). Caffeine prevented T2D-induced alterations of GFAP, vimentin and SNAP25, and improved memory deficits. We conclude that caffeine consumption has beneficial effects counteracting alterations in the hippocampus of GK rats, leading to the improvement of T2D-associated memory impairment.
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Affiliation(s)
- João M N Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Department of Experimental Medical Science, Faculty of Medicine, Lund University, Lund, Sweden.,Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Cecilia Skoug
- Department of Experimental Medical Science, Faculty of Medicine, Lund University, Lund, Sweden.,Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Henrique B Silva
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Rui A Carvalho
- Department of Life Sciences, Faculty of Science and Technology, University of Coimbra, Coimbra, Portugal
| | - Rolf Gruetter
- Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Department of Radiology, University of Lausanne, Lausanne, Switzerland.,Department of Radiology, University of Geneva, Geneva, Switzerland
| | - Rodrigo A Cunha
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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Carlström M, Larsson SC. Coffee consumption and reduced risk of developing type 2 diabetes: a systematic review with meta-analysis. Nutr Rev 2018; 76:395-417. [DOI: 10.1093/nutrit/nuy014] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Mattias Carlström
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Susanna C Larsson
- Unit of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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8
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Peleli M, Carlstrom M. Adenosine signaling in diabetes mellitus and associated cardiovascular and renal complications. Mol Aspects Med 2017; 55:62-74. [DOI: 10.1016/j.mam.2016.12.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 12/18/2016] [Accepted: 12/21/2016] [Indexed: 12/21/2022]
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9
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Functional Analysis of Novel Candidate Regulators of Insulin Secretion in the MIN6 Mouse Pancreatic β Cell Line. PLoS One 2016; 11:e0151927. [PMID: 26986842 PMCID: PMC4795703 DOI: 10.1371/journal.pone.0151927] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 03/07/2016] [Indexed: 01/11/2023] Open
Abstract
Elucidating the regulation of glucose-stimulated insulin secretion (GSIS) in pancreatic β cells is important for understanding and treating diabetes. The pancreatic β cell line, MIN6, retains GSIS but gradually loses it in long-term culture. The MIN6 subclone, MIN6c4, exhibits well-regulated GSIS even after prolonged culture. We previously used DNA microarray analysis to compare gene expression in the parental MIN6 cells and MIN6c4 cells and identified several differentially regulated genes that may be involved in maintaining GSIS. Here we investigated the potential roles of six of these genes in GSIS: Tmem59l (Transmembrane protein 59 like), Scgn (Secretagogin), Gucy2c (Guanylate cyclase 2c), Slc29a4 (Solute carrier family 29, member 4), Cdhr1 (Cadherin-related family member 1), and Celsr2 (Cadherin EGF LAG seven-pass G-type receptor 2). These genes were knocked down in MIN6c4 cells using lentivirus vectors expressing gene-specific short hairpin RNAs (shRNAs), and the effects of the knockdown on insulin expression and secretion were analyzed. Suppression of Tmem59l, Scgn, and Gucy2c expression resulted in significantly decreased glucose- and/or KCl-stimulated insulin secretion from MIN6c4 cells, while the suppression of Slc29a4 expression resulted in increased insulin secretion. Tmem59l overexpression rescued the phenotype of the Tmem59l knockdown MIN6c4 cells, and immunostaining analysis indicated that the TMEM59L protein colocalized with insulin and GM130, a Golgi complex marker, in MIN6 cells. Collectively, our findings suggested that the proteins encoded by Tmem59l, Scgn, Gucy2c, and Slc29a4 play important roles in regulating GSIS. Detailed studies of these proteins and their functions are expected to provide new insights into the molecular mechanisms involved in insulin secretion.
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Ventromedial Hypothalamic Lesions Down-Regulate the Expression of Adora1 Gene in Rat Pancreatic Islets. Pancreas 2016; 45:e1-2. [PMID: 26658041 DOI: 10.1097/mpa.0000000000000390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
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11
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Yang T, Gao X, Sandberg M, Zollbrecht C, Zhang XM, Hezel M, Liu M, Peleli M, Lai EY, Harris RA, Persson AEG, Fredholm BB, Jansson L, Carlström M. Abrogation of adenosine A1 receptor signalling improves metabolic regulation in mice by modulating oxidative stress and inflammatory responses. Diabetologia 2015; 58:1610-20. [PMID: 25835725 DOI: 10.1007/s00125-015-3570-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 03/02/2015] [Indexed: 12/22/2022]
Abstract
AIMS/HYPOTHESIS Adenosine is an important regulator of metabolism; however, the role of the A1 receptor during ageing and obesity is unclear. The aim of this study was to investigate the effects of A1 signalling in modulating metabolic function during ageing. METHODS Age-matched young and aged A 1 (also known as Adora1)-knockout (A1(-/-)) and wild-type (A1(+/+)) mice were used. Metabolic regulation was evaluated by body composition, and glucose and insulin tolerance tests. Isolated islets and islet arterioles were used to detect islet endocrine and vascular function. Oxidative stress and inflammation status were measured in metabolic organs and systemically. RESULTS Advanced age was associated with both reduced glucose clearance and insulin sensitivity, as well as increased visceral adipose tissue (VAT) in A1(+/+) compared with A1(-/-) mice. Islet morphology and insulin content were similar between genotypes, but relative changes in in vitro insulin release following glucose stimulation were reduced in aged A1(+/+) compared with A1(-/-) mice. Islet arteriolar responses to angiotensin II were stronger in aged A1(+/+) mice, this being associated with increased NADPH oxidase activity. Ageing resulted in multiple changes in A1(+/+) compared with A1(-/-) mice, including enhanced NADPH oxidase-derived O2(-) formation and NADPH oxidase isoform 2 (Nox2) protein expression in pancreas and VAT; elevated levels of circulating insulin, leptin and proinflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-12); and accumulation of CD4(+) T cells in VAT. This was associated with impaired insulin signalling in VAT from aged A1(+/+) mice. CONCLUSIONS/INTERPRETATION These studies emphasise that A1 receptors regulate metabolism and islet endocrine and vascular functions during ageing, including via the modulation of oxidative stress and inflammatory responses, among other things.
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Affiliation(s)
- Ting Yang
- Department of Physiology and Pharmacology, Karolinska Institutet, Nanna Svartz Väg 2, SE-171 77, Stockholm, Sweden
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12
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Pulsatile insulin secretion, impaired glucose tolerance and type 2 diabetes. Mol Aspects Med 2015; 42:61-77. [PMID: 25637831 DOI: 10.1016/j.mam.2015.01.003] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 01/09/2015] [Accepted: 01/10/2015] [Indexed: 12/28/2022]
Abstract
Type 2 diabetes (T2DM) results when increases in beta cell function and/or mass cannot compensate for rising insulin resistance. Numerous studies have documented the longitudinal changes in metabolism that occur during the development of glucose intolerance and lead to T2DM. However, the role of changes in insulin secretion, both amount and temporal pattern, has been understudied. Most of the insulin secreted from pancreatic beta cells of the pancreas is released in a pulsatile pattern, which is disrupted in T2DM. Here we review the evidence that changes in beta cell pulsatility occur during the progression from glucose intolerance to T2DM in humans, and contribute significantly to the etiology of the disease. We review the evidence that insulin pulsatility improves the efficacy of secreted insulin on its targets, particularly hepatic glucose production, but also examine evidence that pulsatility alters or is altered by changes in peripheral glucose uptake. Finally, we summarize our current understanding of the biophysical mechanisms responsible for oscillatory insulin secretion. Understanding how insulin pulsatility contributes to normal glucose homeostasis and is altered in metabolic disease states may help improve the treatment of T2DM.
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Yip L, Fathman CG. Type 1 diabetes in mice and men: gene expression profiling to investigate disease pathogenesis. Immunol Res 2015; 58:340-50. [PMID: 24682832 DOI: 10.1007/s12026-014-8501-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Type 1 diabetes (T1D) is a complex polygenic disease that is triggered by various environmental factors in genetically susceptible individuals. The emphasis placed on genome-wide association studies to explain the genetics of T1D has failed to advance our understanding of T1D pathogenesis or identify biomarkers of disease progression or therapeutic targets. Using the nonobese diabetic (NOD) mouse model of T1D and the non-disease prone congenic NOD.B10 mice, our laboratory demonstrated striking tissue-specific and age-dependent changes in gene expression during disease progression. We established a "roadmap" of differential gene expression and used this to identify candidate genes in mice (and human orthologs) that play a role in disease pathology. Here, we describe two genes, Deformed epidermal autoregulatory factor 1 (Deaf1) and Adenosine A1 receptor (Adora1), that are differentially expressed and alternatively spliced in the pancreatic lymph nodes or islets of NOD mice and T1D patients to form dominant-negative non-functional isoforms. Loss of Deaf1 function leads to reduced peripheral tissue antigen expression in lymph node stromal cells and may contribute to a breakdown in peripheral tolerance, while reduced Adora1 function results in an early intrinsic alpha cell defect that may explain the hyperglucagonemia and resulting beta cell stress observed prior to the onset of diabetes. Remarkably, both genes were also alternatively spliced in the same tissues of auto-antibody positive prediabetic patients, and these splicing events resulted in similar downstream effects as those seen in NOD mice. These findings demonstrate the value of gene expression profiling in studying disease pathogenesis in T1D.
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Affiliation(s)
- Linda Yip
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, 269 Campus Drive, CCSR Room 2225, Stanford, CA, 94305-5166, USA
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Tengholm A. Purinergic P2Y1 receptors take centre stage in autocrine stimulation of human beta cells. Diabetologia 2014; 57:2436-9. [PMID: 25277952 DOI: 10.1007/s00125-014-3392-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 09/10/2014] [Indexed: 12/20/2022]
Abstract
Insulin secretory vesicles contain high concentrations of adenine nucleotides, which are co-released with insulin during exocytosis. There is strong evidence that ATP and ADP serve as autocrine messengers in pancreatic beta cells, but the functional effects and detailed mechanisms of action are under debate. In this issue of Diabetologia, Khan and colleagues (DOI: 10.1007/s00125-014-3368-8 ) present the results of their study of autocrine purinergic signalling in isolated human beta cells. Using a combination of electrophysiological techniques, Ca(2+) imaging and measurements of insulin secretion, it is demonstrated that voltage-dependent Ca(2+) influx triggers release of ATP/ADP, which activates purinergic receptors of the Gq/11-coupled P2Y1 isoform. Activation of these receptors leads to membrane depolarisation and phospholipase C-mediated mobilisation of Ca(2+) from endoplasmic reticulum stores, which amplifies the exocytosis-triggering Ca(2+) signal. In contrast, there is little evidence for involvement of ionotropic P2X receptors in the autocrine stimulation of human beta cells. This commentary discusses these findings as well as various functional and therapeutic implications of the complex purinergic signalling network in the pancreatic islet.
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Affiliation(s)
- Anders Tengholm
- Department of Medical Cell Biology, Uppsala University, Biomedical Centre, Box 571, SE-751 23, Uppsala, Sweden,
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15
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Szkudelski T, Szkudelska K. Regulatory role of adenosine in insulin secretion from pancreatic β-cells--action via adenosine A₁ receptor and beyond. J Physiol Biochem 2014; 71:133-40. [PMID: 25432862 DOI: 10.1007/s13105-014-0371-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 11/17/2014] [Indexed: 01/04/2023]
Abstract
Under physiological conditions, insulin secretion from pancreatic β-cells is tightly regulated by different factors, including nutrients, nervous system, and other hormones. Pancreatic β-cells are also influenced by paracrine and autocrine interactions. The results of rodent studies indicate that adenosine is present within pancreatic islets and is implicated in the regulation of insulin secretion; however, effects depend on adenosine and glucose concentrations. Moreover, species differences in adenosine action were found. In rat islets, low adenosine was demonstrated to decrease glucose-induced insulin secretion and this effect is mediated via adenosine A1 receptor. In the presence of high adenosine concentrations, other mechanisms are activated and glucose-induced insulin secretion is increased. It is also well established that suppression of adenosine action increases insulin-secretory response of β-cells to glucose. In mouse islets, low adenosine concentrations do not significantly affect insulin secretion. However, in the presence of higher adenosine concentrations, potentiation of glucose-induced insulin secretion was demonstrated. It is also known that upon stimulation of insulin secretion, both rat and mouse islets release ATP. In rat islets, ATP undergoes extracellular conversion to adenosine. However, mouse islets are unable to convert extracellularly ATP to adenosine and adenosine arises from intracellular ATP degradation.
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Affiliation(s)
- Tomasz Szkudelski
- Department of Animal Physiology and Biochemistry, Poznan University of Life Sciences, Wolynska 35, 60-637, Poznan, Poland,
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Burnstock G. Purinergic signalling in endocrine organs. Purinergic Signal 2014; 10:189-231. [PMID: 24265070 PMCID: PMC3944044 DOI: 10.1007/s11302-013-9396-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 01/08/2023] Open
Abstract
There is widespread involvement of purinergic signalling in endocrine biology. Pituitary cells express P1, P2X and P2Y receptor subtypes to mediate hormone release. Adenosine 5'-triphosphate (ATP) regulates insulin release in the pancreas and is involved in the secretion of thyroid hormones. ATP plays a major role in the synthesis, storage and release of catecholamines from the adrenal gland. In the ovary purinoceptors mediate gonadotrophin-induced progesterone secretion, while in the testes, both Sertoli and Leydig cells express purinoceptors that mediate secretion of oestradiol and testosterone, respectively. ATP released as a cotransmitter with noradrenaline is involved in activities of the pineal gland and in the neuroendocrine control of the thymus. In the hypothalamus, ATP and adenosine stimulate or modulate the release of luteinising hormone-releasing hormone, as well as arginine-vasopressin and oxytocin. Functionally active P2X and P2Y receptors have been identified on human placental syncytiotrophoblast cells and on neuroendocrine cells in the lung, skin, prostate and intestine. Adipocytes have been recognised recently to have endocrine function involving purinoceptors.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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Hellman B, Grapengiesser E. Glucose-induced inhibition of insulin secretion. Acta Physiol (Oxf) 2014; 210:479-88. [PMID: 24354538 DOI: 10.1111/apha.12217] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 11/04/2013] [Accepted: 12/16/2013] [Indexed: 12/14/2022]
Abstract
Increase in glucose is known to elevate the concentration of cytoplasmic Ca(2+) ([Ca(2+) ]i ) in pancreatic β-cells and stimulate insulin secretion. However, rise of glucose can also lower [Ca(2+) ]i and inhibit insulin release. In the present review, we examine the mechanisms for this inhibition and highlight its importance for the healthy β-cell and the development of diabetes. It is possible to distinguish between 60 and 90 s of prompt inhibition and the late inhibition seen after the first-phase peak of insulin release. The introductory inhibition is characteristic of the healthy β-cell and mediated by sequestration of [Ca(2+) ]i in the endoplasmic reticulum. This inhibition is easily seen in studies of isolated islets but too brief to be detected in a conventional intravenous glucose tolerance test. Coupled to simultaneous rise of glucagon, the introductory suppression of insulin release is the starting point for the antiphase relation between the subsequent insulin and glucagon pulses. Another effect of the initial suppression is to increase the pool of readily releasable granules responsible for the first-phase release of insulin. The presence of late inhibition of insulin release is an indicator of β-cell dysfunction. Patients with type 2 diabetes often respond to intravenous bolus injection of glucose with 5-10 min of late suppression of circulating insulin.
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Affiliation(s)
- B. Hellman
- Department of Medical Cell Biology; University of Uppsala; Uppsala Sweden
| | - E. Grapengiesser
- Department of Medical Cell Biology; University of Uppsala; Uppsala Sweden
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Yip L, Taylor C, Whiting CC, Fathman CG. Diminished adenosine A1 receptor expression in pancreatic α-cells may contribute to the pathology of type 1 diabetes. Diabetes 2013; 62:4208-19. [PMID: 24264405 PMCID: PMC3837064 DOI: 10.2337/db13-0614] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Prediabetic NOD mice exhibit hyperglucagonemia, possibly due to an intrinsic α-cell defect. Here, we show that the expression of a potential glucagon inhibitor, the adenosine A1 receptor (Adora1), is gradually diminished in α-cells of NOD mice, autoantibody-positive (AA(+)) and overtly type 1 diabetic (T1D) patients during the progression of disease. We demonstrated that islet inflammation was associated with loss of Adora1 expression through the alternative splicing of Adora1. Expression of the spliced variant (Adora1-Var) was upregulated in the pancreas of 12-week-old NOD versus age-matched NOD.B10 (non-diabetes-susceptible) control mice and was detected in the pancreas of AA(+) patients but not in control subjects or overtly diabetic patients, suggesting that inflammation drives the splicing of Adora1. We subsequently demonstrated that Adora1-Var expression was upregulated in the islets of NOD.B10 mice after exposure to inflammatory cytokines and in the pancreas of NOD.SCID mice after adoptive transfer of activated autologous splenocytes. Adora1-Var encodes a dominant-negative N-terminal truncated isoform of Adora1. The splicing of Adora1 and loss of Adora1 expression on α-cells may explain the hyperglucagonemia observed in prediabetic NOD mice and may contribute to the pathogenesis of human T1D and NOD disease.
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Amisten S, Salehi A, Rorsman P, Jones PM, Persaud SJ. An atlas and functional analysis of G-protein coupled receptors in human islets of Langerhans. Pharmacol Ther 2013; 139:359-91. [DOI: 10.1016/j.pharmthera.2013.05.004] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 05/03/2013] [Indexed: 12/17/2022]
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Ohtani M, Oka T, Ohura K. Possible involvement of A₂A and A₃ receptors in modulation of insulin secretion and β-cell survival in mouse pancreatic islets. Gen Comp Endocrinol 2013; 187:86-94. [PMID: 23453966 DOI: 10.1016/j.ygcen.2013.02.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 02/07/2013] [Accepted: 02/12/2013] [Indexed: 10/27/2022]
Abstract
Adenosine A1, A₂A, A₂B and A₃ receptor mRNAs were found to be expressed in mouse pancreatic islets and Beta-TC6 cells but their physiological or pharmacological actions are not fully clarified. We showed that adenosine (100 μM) augmented insulin secretion by islets in the presence of either normal (5.5 mM) or a high concentration of glucose (20 mM). The augmentation of insulin secretion in the presence of high glucose was blocked by an A₂A antagonist, but not by A₂B and A₃ antagonists, while an A₁ antagonist potentiated the adenosine effect. An adenosine analogue 5'-N-ethylcarboxamidoadenosine (NECA) as well as A₁, A₂A and A₃ receptor agonists also produced stimulation. On the other hand, an A₃ agonist markedly reduced Beta-TC6 cell proliferation and the islet cell viability, while adenosine and NECA did not. The effect of A₃ agonist was partially blocked by the A₃ antagonist. In addition, treatment with the A₃ agonist produced a small but significant extent of apoptosis in Beta-TC6 cells as judged by terminal transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) assay. These results combined together suggested that like the A₁ receptor, activation of A₂A receptors by adenosine results in augmented insulin secretion, while the A₃ receptor is involved in modulation of the survival of pancreatic β-cells.
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Affiliation(s)
- M Ohtani
- Department of Pharmacology, Osaka Dental University, 8-1 Kuzuhahanazono-cho, Hirakata, Osaka 573-1121, Japan.
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Yang GK, Fredholm BB, Kieffer TJ, Kwok YN. Improved blood glucose disposal and altered insulin secretion patterns in adenosine A(1) receptor knockout mice. Am J Physiol Endocrinol Metab 2012; 303:E180-90. [PMID: 22550063 DOI: 10.1152/ajpendo.00050.2012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is characterized by the inability of the pancreatic β-cells to secrete enough insulin to meet the demands of the body. Therefore, research of potential therapeutic approaches to treat T2DM has focused on increasing insulin output from β-cells or improving systemic sensitivity to circulating insulin. In this study, we examined the role of the A(1) receptor in glucose homeostasis with the use of A(1) receptor knockout mice (A(1)R(-/-)). A(1)R(-/-) mice exhibited superior glucose tolerance compared with wild-type controls. However, glucose-stimulated insulin release, insulin sensitivity, weight gain, and food intake were comparable between the two genotypes. Following a glucose challenge, plasma glucagon levels in wild-type controls decreased, but this was not observed in A(1)R(-/-) mice. In addition, pancreas perfusion with oscillatory glucose levels of 10-min intervals produced a regular pattern of pulsatile insulin release with a 10-min cycling period in wild-type controls and 5 min in A(1)R(-/-) mice. When the mice were fed a high-fat diet (HFD), both genotypes exhibited impaired glucose tolerance and insulin resistance. Increased insulin release was observed in HFD-fed mice in both genotypes, but increased glucagon release was observed only in HFD-fed A(1)R(-/-) mice. In addition, the regular patterns of insulin release following oscillatory glucose perfusion were abolished in HFD-fed mice in both genotypes. In conclusion, A(1) receptors in the pancreas are involved in regulating the temporal patterns of insulin release, which could have implications in the development of glucose intolerance seen in T2DM.
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Affiliation(s)
- Gary K Yang
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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Abstract
Pancreatic cells contain specialised stores for ATP. Purinergic receptors (P2 and P1) and ecto-nucleotidases are expressed in both endocrine and exocrine calls, as well as in stromal cells. The pancreas, especially the endocrine cells, were an early target for the actions of ATP. After the historical perspective of purinergic signalling in the pancreas, the focus of this review will be the physiological functions of purinergic signalling in the regulation of both endocrine and exocrine pancreas. Next, we will consider possible interaction between purinergic signalling and other regulatory systems and their relation to nutrient homeostasis and cell survival. The pancreas is an organ exhibiting several serious diseases - cystic fibrosis, pancreatitis, pancreatic cancer and diabetes - and some are associated with changes in life-style and are increasing in incidence. There is upcoming evidence for the role of purinergic signalling in the pathophysiology of the pancreas, and the new challenge is to understand how it is integrated with other pathological processes.
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Affiliation(s)
- G Burnstock
- University College Medical School, Autonomic Neuroscience Centre, Rowland Hill Street, London NW3 2PF, UK.
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23
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Abstract
OBJECTIVES Pulsatile insulin release into the portal vein is critically dependent on entrainment of the islets in the pancreas into a common oscillatory phase. Because the pulses reflect periodic variations of the cytoplasmic Ca concentration ([Ca]i), we studied whether the neurotransmitters adenosine triphosphate (ATP) and acetylcholine promote synchronization of [Ca]i oscillations between islets lacking contact. METHODS Medium-sized and small mouse islets and cell aggregates were used for measuring [Ca]i with the indicator fura-2. RESULTS Exposure to acetylcholine resulted in an initial [Ca]i peak followed by disappearance of the [Ca]i oscillations induced by 11-mmol/L glucose. The effect of ATP was often restricted to an elusive [Ca]i peak. The incidence of distinct [Ca]i responses to ATP increased under conditions (accelerated superfusion, small islets, or cell aggregates) intended to counteract purinoceptor desensitization owing to intercellular accumulation of ATP. Attempts to imitate neural activity by brief (15 seconds) exposure to ATP or acetylcholine resulted in temporary synchronization of the glucose-induced [Ca]i oscillations between islets lacking contact. CONCLUSIONS The data support the idea that purinergic signaling has a key role for coordinating the oscillatory activity of the islets in the pancreas, reinforcing previous arguments for the involvement of nonadrenergic, noncholinergic neurons.
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Hellman B, Salehi A, Grapengiesser E, Gylfe E. Isolated mouse islets respond to glucose with an initial peak of glucagon release followed by pulses of insulin and somatostatin in antisynchrony with glucagon. Biochem Biophys Res Commun 2011; 417:1219-23. [PMID: 22227186 DOI: 10.1016/j.bbrc.2011.12.113] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 12/22/2011] [Indexed: 01/08/2023]
Abstract
Recent studies of isolated human islets have shown that glucose induces hormone release with repetitive pulses of insulin and somatostatin in antisynchrony with those of glucagon. Since the mouse is the most important animal model we studied the temporal relation between hormones released from mouse islets. Batches of 5-10 islets were perifused and the hormones measured with radioimmunoassay in 30s fractions. At 3mM glucose, hormone secretion was stable with no detectable pulses of glucagon, insulin or somatostatin. Increase of glucose to 20mM resulted in an early secretory phase with a glucagon peak followed by peaks of insulin and somatostatin. Subsequent hormone secretion was pulsatile with a periodicity of 5min. Cross-correlation analyses showed that the glucagon pulses were antisynchronous to those of insulin and somatostatin. In contrast to the marked stimulation of insulin and somatostatin secretion, the pulsatility resulted in inhibition of overall glucagon release. The cytoarchitecture of mouse islets differs from that of human islets, which may affect the interactions between the hormone-producing cells. Although indicating that paracrine regulation is important for the characteristic patterns of pulsatile hormone secretion, the mouse data mimic those of human islets with more than 20-fold variations of the insulin/glucagon ratio. The data indicate that the mouse serves as an appropriate animal model for studying the temporal relation between the islet hormones controlling glucose production in the liver.
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Affiliation(s)
- Bo Hellman
- Department of Medical Cell Biology, University of Uppsala, SE-75123 Uppsala, Sweden.
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Fredholm BB, Johansson S, Wang YQ. Adenosine and the Regulation of Metabolism and Body Temperature. ADVANCES IN PHARMACOLOGY 2011; 61:77-94. [DOI: 10.1016/b978-0-12-385526-8.00003-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Burnstock G, Fredholm BB, North RA, Verkhratsky A. The birth and postnatal development of purinergic signalling. Acta Physiol (Oxf) 2010; 199:93-147. [PMID: 20345419 DOI: 10.1111/j.1748-1716.2010.02114.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The purinergic signalling system is one of the most ancient and arguably the most widespread intercellular signalling system in living tissues. In this review we present a detailed account of the early developments and current status of purinergic signalling. We summarize the current knowledge on purinoceptors, their distribution and role in signal transduction in various tissues in physiological and pathophysiological conditions.
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Affiliation(s)
- G Burnstock
- Autonomic Neuroscience Centre, Royal Free and University College Medical School, London, UK.
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Abstract
The mechanisms and clinical importance of pulsatile insulin release are presented against the background of more than half a century of companionship with the islets of Langerhans. The insulin-secreting beta-cells are oscillators with intrinsic variations of cytoplasmic ATP and Ca(2+). Within the islets the beta-cells are mutually entrained into a common rhythm by gap junctions and diffusible factors (ATP). Synchronization of the different islets in the pancreas is supposed to be due to adjustment of the oscillations to the same phase by neural output of acetylcholine and ATP. Studies of hormone secretion from the perfused pancreas of rats and mice revealed that glucose induces pulses of glucagon anti-synchronous with pulses of insulin and somatostatin. The anti-synchrony may result from a paracrine action of somatostatin on the glucagon-producing alpha-cells. Purinoceptors have a key function for pulsatile release of islet hormones. It was possible to remove the glucagon and somatostatin pulses with maintenance of those of insulin with an inhibitor of the P2Y(1) receptors. Knock-out of the adenosine A(1) receptor prolonged the pulses of glucagon and somatostatin without affecting the duration of the insulin pulses. Studies of isolated human islets indicate similar relations between pulses of insulin, glucagon, and somatostatin as found during perfusion of the rodent pancreas. The observation of reversed cycles of insulin and glucagon adds to the understanding how the islets regulate hepatic glucose production. Current protocols for pulsatile intravenous infusion therapy (PIVIT) should be modified to mimic the anti-synchrony between insulin and glucagon normally seen in the portal blood.
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Affiliation(s)
- Bo Hellman
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden.
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