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Dance A, Fernandes J, Toussaint B, Vaillant E, Boutry R, Baron M, Loiselle H, Balkau B, Charpentier G, Franc S, Ibberson M, Marre M, Gernay M, Fadeur M, Paquot N, Vaxillaire M, Boissel M, Amanzougarene S, Derhourhi M, Khamis A, Froguel P, Bonnefond A. Exploring the role of purinergic receptor P2RY1 in type 2 diabetes risk and pathophysiology: Insights from human functional genomics. Mol Metab 2024; 79:101867. [PMID: 38159881 PMCID: PMC10792753 DOI: 10.1016/j.molmet.2023.101867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 12/19/2023] [Accepted: 12/27/2023] [Indexed: 01/03/2024] Open
Abstract
OBJECTIVE Human functional genomics has proven powerful in discovering drug targets for common metabolic disorders. Through this approach, we investigated the involvement of the purinergic receptor P2RY1 in type 2 diabetes (T2D). METHODS P2RY1 was sequenced in 9,266 participants including 4,177 patients with T2D. In vitro analyses were then performed to assess the functional effect of each variant. Expression quantitative trait loci (eQTL) analysis was performed in pancreatic islets from 103 pancreatectomized individuals. The effect of P2RY1 on glucose-stimulated insulin secretion was finally assessed in human pancreatic beta cells (EndoCβH5), and RNA sequencing was performed on these cells. RESULTS Sequencing P2YR1 in 9,266 participants revealed 22 rare variants, seven of which were loss-of-function according to our in vitro analyses. Carriers, except one, exhibited impaired glucose control. Our eQTL analysis of human islets identified P2RY1 variants, in a beta-cell enhancer, linked to increased P2RY1 expression and reduced T2D risk, contrasting with variants located in a silent region associated with decreased P2RY1 expression and increased T2D risk. Additionally, a P2RY1-specific agonist increased insulin secretion upon glucose stimulation, while the antagonist led to decreased insulin secretion. RNA-seq highlighted TXNIP as one of the main transcriptomic markers of insulin secretion triggered by P2RY1 agonist. CONCLUSION Our findings suggest that P2RY1 inherited or acquired dysfunction increases T2D risk and that P2RY1 activation stimulates insulin secretion. Selective P2RY1 agonists, impermeable to the blood-brain barrier, could serve as potential insulin secretagogues.
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Affiliation(s)
- Arnaud Dance
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Justine Fernandes
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Bénédicte Toussaint
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Emmanuel Vaillant
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Raphaël Boutry
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Morgane Baron
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Hélène Loiselle
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Beverley Balkau
- Paris-Saclay University, Paris-Sud University, UVSQ, Center for Research in Epidemiology and Population Health, Inserm U1018 Clinical Epidemiology, Villejuif, France
| | - Guillaume Charpentier
- CERITD (Centre d'Étude et de Recherche pour l'Intensification du Traitement du Diabète), Evry, France
| | - Sylvia Franc
- CERITD (Centre d'Étude et de Recherche pour l'Intensification du Traitement du Diabète), Evry, France; Department of Diabetes, Sud-Francilien Hospital, Paris-Sud University, Corbeil-Essonnes, France
| | - Mark Ibberson
- Vital-IT Group, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Michel Marre
- Institut Necker-Enfants Malades, Inserm, Université de Paris, Paris, France; Clinique Ambroise Paré, Neuilly-sur-Seine, France
| | - Marie Gernay
- Department of Diabetology, Nutrition and Metabolic Diseases, Sart Tilman University Hospital Center, Liège, Belgium
| | - Marjorie Fadeur
- Department of Diabetology, Nutrition and Metabolic Diseases, Sart Tilman University Hospital Center, Liège, Belgium
| | - Nicolas Paquot
- Department of Diabetology, Nutrition and Metabolic Diseases, Sart Tilman University Hospital Center, Liège, Belgium
| | - Martine Vaxillaire
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Mathilde Boissel
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Souhila Amanzougarene
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Mehdi Derhourhi
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France
| | - Amna Khamis
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France; Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Philippe Froguel
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France; Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom.
| | - Amélie Bonnefond
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille University Hospital, Lille, France; Université de Lille, Lille, France; Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom.
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2
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Pereira ADS, Miron VV, Castro MFV, Bottari NB, Assmann CE, Nauderer JN, Bissacotti BF, Mostardeiro VB, Stefanello N, Baldissarelli J, Palma TV, Morsch VMM, Schetinger MRC. Neuromodulatory effect of the combination of metformin and vitamin D 3 triggered by purinergic signaling in type 1 diabetes induced-rats. Mol Cell Endocrinol 2023; 563:111852. [PMID: 36657632 DOI: 10.1016/j.mce.2023.111852] [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: 10/24/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 01/18/2023]
Abstract
Several studies have indicated the vitamin D deficiency in the development of macro- and microvascular complications of diabetes mellitus (DM) including DM-related cognitive dysfunction. The purinergic system plays an important role in the modulation of a variety of mechanisms, including neuroinflammation, plasticity, and cell-cell communication. In addition, purines, their receptors, and enzymes can regulate the purinergic axis at different levels in type 1 DM (T1DM). This study evaluated the effects of vitamin D3 alone or in combination with metformin in the behavioral performance of streptozotocin-induced T1DM rats. The effects of this combination on the metabolism of ATP and ADP were also studied by NTPDase (CD39), AMP by 5'-nucleotidase (CD73), and adenosine by adenosine deaminase (E-ADA) in the brain and peripheral lymphocytes of type 1 diabetic STZ-induced rats. The results showed that anxiety and memory loss from the DM condition reverted after 30 days of vitamin D3 treatment. Furthermore, the DM state affected systemic enzymes, with no effect on the central enzymes hydrolyzing extracellular nucleotides and nucleosides. Vitamin D3 treatment positively regulated ectonucleotidase (NTPDase and 5'-nucleotidase) activity, E-ADA, and the purinergic receptors as a mechanism to prevent oxidative damage in the cerebral cortex of T1DM rats. A neuroprotector effect of vitamin D3 through adenosine signaling was also observed, by regulating A1 and A2A receptors proteins levels. The present findings suggest that purinergic signaling through vitamin D3 modulation may be a novel alternative strategy for T1DM treatment, and may compensate for the negative changes in the central nervous system.
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Affiliation(s)
- Aline da Silva Pereira
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil.
| | - Vanessa Valéria Miron
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Milagros Fanny Vera Castro
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Nathieli Bianchin Bottari
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Charles Elias Assmann
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Jelson Norberto Nauderer
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Bianca Fagan Bissacotti
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Vitor Bastianello Mostardeiro
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Naiara Stefanello
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Jucimara Baldissarelli
- Departamento de Fisiologia e Farmacologia, Universidade Federal de Pelotas (UFPEL), Pelotas, RS, Brazil
| | - Taís Vidal Palma
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Vera Maria Melchiors Morsch
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Maria Rosa Chitolina Schetinger
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil.
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3
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Chen CW, Guan BJ, Alzahrani MR, Gao Z, Gao L, Bracey S, Wu J, Mbow CA, Jobava R, Haataja L, Zalavadia AH, Schaffer AE, Lee H, LaFramboise T, Bederman I, Arvan P, Mathews CE, Gerling IC, Kaestner KH, Tirosh B, Engin F, Hatzoglou M. Adaptation to chronic ER stress enforces pancreatic β-cell plasticity. Nat Commun 2022; 13:4621. [PMID: 35941159 PMCID: PMC9360004 DOI: 10.1038/s41467-022-32425-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 08/01/2022] [Indexed: 11/30/2022] Open
Abstract
Pancreatic β-cells are prone to endoplasmic reticulum (ER) stress due to their role in insulin secretion. They require sustainable and efficient adaptive stress responses to cope with this stress. Whether episodes of chronic stress directly compromise β-cell identity is unknown. We show here under reversible, chronic stress conditions β-cells undergo transcriptional and translational reprogramming associated with impaired expression of regulators of β-cell function and identity. Upon recovery from stress, β-cells regain their identity and function, indicating a high degree of adaptive plasticity. Remarkably, while β-cells show resilience to episodic ER stress, when episodes exceed a threshold, β-cell identity is gradually lost. Single cell RNA-sequencing analysis of islets from type 1 diabetes patients indicates severe deregulation of the chronic stress-adaptation program and reveals novel biomarkers of diabetes progression. Our results suggest β-cell adaptive exhaustion contributes to diabetes pathogenesis.
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Affiliation(s)
- Chien-Wen Chen
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA.
| | - Bo-Jhih Guan
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Mohammed R Alzahrani
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Zhaofeng Gao
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Long Gao
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Syrena Bracey
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Jing Wu
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Cheikh A Mbow
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Raul Jobava
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Leena Haataja
- The Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Ajay H Zalavadia
- Lerner Research Institute, Cleveland Clinic, 9620 Carnegie Ave N Bldg, Cleveland, OH, 44106, US
| | - Ashleigh E Schaffer
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Hugo Lee
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, 53706, USA
| | - Thomas LaFramboise
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Ilya Bederman
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Peter Arvan
- The Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Clayton E Mathews
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, US
| | - Ivan C Gerling
- Department of Medicine, University of Tennessee, Memphis, TN, US
| | - Klaus H Kaestner
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Boaz Tirosh
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
- The Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Feyza Engin
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, 53706, USA.
- Department of Medicine, Division of Endocrinology, Diabetes & Metabolism, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, 53705, USA.
| | - Maria Hatzoglou
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA.
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4
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Marcheva B, Weidemann BJ, Taguchi A, Perelis M, Ramsey KM, Newman MV, Kobayashi Y, Omura C, Manning Fox JE, Lin H, Macdonald PE, Bass J. P2Y1 purinergic receptor identified as a diabetes target in a small-molecule screen to reverse circadian β-cell failure. eLife 2022; 11:e75132. [PMID: 35188462 PMCID: PMC8860442 DOI: 10.7554/elife.75132] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 01/21/2022] [Indexed: 12/18/2022] Open
Abstract
The mammalian circadian clock drives daily oscillations in physiology and behavior through an autoregulatory transcription feedback loop present in central and peripheral cells. Ablation of the core clock within the endocrine pancreas of adult animals impairs the transcription and splicing of genes involved in hormone exocytosis and causes hypoinsulinemic diabetes. Here, we developed a genetically sensitized small-molecule screen to identify druggable proteins and mechanistic pathways involved in circadian β-cell failure. Our approach was to generate β-cells expressing a nanoluciferase reporter within the proinsulin polypeptide to screen 2640 pharmacologically active compounds and identify insulinotropic molecules that bypass the secretory defect in CRISPR-Cas9-targeted clock mutant β-cells. We validated hit compounds in primary mouse islets and identified known modulators of ligand-gated ion channels and G-protein-coupled receptors, including the antihelmintic ivermectin. Single-cell electrophysiology in circadian mutant mouse and human cadaveric islets revealed ivermectin as a glucose-dependent secretagogue. Genetic, genomic, and pharmacological analyses established the P2Y1 receptor as a clock-controlled mediator of the insulinotropic activity of ivermectin. These findings identify the P2Y1 purinergic receptor as a diabetes target based upon a genetically sensitized phenotypic screen.
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Affiliation(s)
- Biliana Marcheva
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
| | - Benjamin J Weidemann
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
| | - Akihiko Taguchi
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
- Division of Endocrinology, Metabolism, Hematological Science and Therapeutics, Department of Bio-Signal Analysis, Yamaguchi University, Graduate School of Medicine, 1-1-1YamaguchiJapan
| | - Mark Perelis
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
- Ionis Pharmaceuticals, IncCarlsbadUnited States
| | - Kathryn Moynihan Ramsey
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
| | - Marsha V Newman
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
| | - Yumiko Kobayashi
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
| | - Chiaki Omura
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
| | - Jocelyn E Manning Fox
- Department of Pharmacology, Alberta Diabetes Institute, University of AlbertaEdmonton, ABCanada
| | - Haopeng Lin
- Department of Pharmacology, Alberta Diabetes Institute, University of AlbertaEdmonton, ABCanada
| | - Patrick E Macdonald
- Department of Pharmacology, Alberta Diabetes Institute, University of AlbertaEdmonton, ABCanada
| | - Joseph Bass
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
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5
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Kumagawa T, Moro N, Maeda T, Kobayashi M, Furukawa Y, Shijo K, Yoshino A. Anti-inflammatory effect of P2Y1 receptor blocker MRS2179 in a rat model of traumatic brain injury. Brain Res Bull 2022; 181:46-54. [DOI: 10.1016/j.brainresbull.2022.01.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/16/2022] [Accepted: 01/19/2022] [Indexed: 02/07/2023]
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6
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Mesto N, Movassat J, Tourrel-Cuzin C. P2-type purinergic signaling in the regulation of pancreatic β-cell functional plasticity as a promising novel therapeutic approach for the treatment of type 2 diabetes? Front Endocrinol (Lausanne) 2022; 13:1099152. [PMID: 37065173 PMCID: PMC10099247 DOI: 10.3389/fendo.2022.1099152] [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: 11/15/2022] [Accepted: 11/29/2022] [Indexed: 12/13/2022] Open
Abstract
Diabetes Mellitus is a metabolic disorder characterized by a chronic hyperglycemia due to an impaired insulin secretion and a decreased in peripheral insulin sensitivity. This disease is a major public health problem due to it sharp prevalence. Therefore, it is crucial to readapt therapeutic approaches for the treatment of this pathology. One of the strategies would be through P2-type purinergic receptors pathway via ATP binding. In addition to its well-known role as an intracellular energy intermediary in numerous biochemical and physiological processes, ATP is also an important extracellular signaling molecule. ATP mediates its effects by binding and activating two classes of P2 purinoreceptors: P2X receptors that are ligand-gated ion channel receptors, existing in seven isoforms (P2X 1 to 7) and P2Y receptors that are G-protein coupled receptors, existing in eight isoforms (P2Y 1/2/4/6/11/12/13/14). These receptors are ubiquitously distributed and involved in numerous physiological processes in several tissues. The concept of purinergic signaling, originally formulated by Geoffrey Burnstock (1929-2020), was also found to mediate various responses in the pancreas. Several studies have shown that P2 receptors are expressed in the endocrine pancreas, notably in β cells, where ATP could modulate their function but also their plasticity and thus play a physiological role in stimulating insulin secretion to face some metabolic demands. In this review, we provide a historical perspective and summarize current knowledge on P2-type purinergic signaling in the regulation of pancreatic β-cell functional plasticity, which would be a promising novel therapeutic approach for the treatment of type 2 diabetes.
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Mesto N, Bailbe D, Eskandar M, Pommier G, Gil S, Tolu S, Movassat J, Tourrel-Cuzin C. Involvement of P2Y signaling in the restoration of glucose-induced insulin exocytosis in pancreatic β cells exposed to glucotoxicity. J Cell Physiol 2021; 237:881-896. [PMID: 34435368 DOI: 10.1002/jcp.30564] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 07/27/2021] [Accepted: 08/13/2021] [Indexed: 12/14/2022]
Abstract
Purinergic P2Y receptors, by binding adenosine triphosphate (ATP), are known for enhancing glucose-stimulated insulin secretion (GSIS) in pancreatic β cells. However, the impact of these receptors in the actin dynamics and insulin granule exocytosis in these cells is not established, neither in normal nor in glucotoxic environment. In this study, we investigate the involvement of P2Y receptors on the behavior of insulin granules and the subcortical actin network dynamics in INS-1 832/13 β cells exposed to normal or glucotoxic environment and their role in GSIS. Our results show that the activation of P2Y purinergic receptors by ATP or its agonist increase the insulin granules exocytosis and the reorganization of the subcortical actin network and participate in the potentiation of GSIS. In addition, their activation in INS-1832/13 β-cells, with impaired insulin secretion following exposure to elevated glucose levels, restores GSIS competence through the distal steps of insulin exocytosis. These results are confirmed ex vivo by perifusion experiments on islets from type 2 diabetic (T2D) Goto-Kakizaki (GK) rats. Indeed, the P2Y receptor agonist restores the altered GSIS, which is normally lost in this T2D animal model. Moreover, we observed an improvement of the glucose tolerance, following the acute intraperitoneal injection of the P2Y agonist concomitantly with glucose, in diabetic GK rats. All these data provide new insights into the unprecedented therapeutic role of P2Y purinergic receptors in the pathophysiology of T2D.
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Affiliation(s)
- Nour Mesto
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
| | - Danielle Bailbe
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
| | - Myriam Eskandar
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
| | - Gaëlle Pommier
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
| | - Stéphanie Gil
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France.,Université de Paris, UFR Sciences du Vivant (SDV), Paris, France
| | - Stefania Tolu
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
| | - Jamileh Movassat
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
| | - Cécile Tourrel-Cuzin
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
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8
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Caruso V, Zuccarini M, Di Iorio P, Muhammad I, Ronci M. Metabolic Changes Induced by Purinergic Signaling: Role in Food Intake. Front Pharmacol 2021; 12:655989. [PMID: 33995077 PMCID: PMC8117016 DOI: 10.3389/fphar.2021.655989] [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: 01/19/2021] [Accepted: 04/09/2021] [Indexed: 01/30/2023] Open
Abstract
The purinergic signalling has a well-established role in the regulation of energy homeostasis, but there is growing evidence of its implication in the control of food intake. In this review, we provide an integrative view of the molecular mechanisms leading to changes in feeding behaviour within hypothalamic neurons following purinergic receptor activation. We also highlight the importance of purinergic signalling in metabolic homeostasis and the possibility of targeting its receptors for therapeutic purposes.
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Affiliation(s)
- Vanni Caruso
- School of Pharmacy and Pharmacology, University of Tasmania, Hobart, TAS, Australia.,Institute for Research on Pain, ISAL-Foundation, Rimini, Italy
| | - Mariachiara Zuccarini
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, Chieti, Italy.,Center for Advanced Studies and Technologies (CAST), University of Chieti-Pescara, Chieti, Italy
| | - Patrizia Di Iorio
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, Chieti, Italy.,Center for Advanced Studies and Technologies (CAST), University of Chieti-Pescara, Chieti, Italy
| | - Ishaq Muhammad
- School of Pharmacy and Pharmacology, University of Tasmania, Hobart, TAS, Australia
| | - Maurizio Ronci
- Center for Advanced Studies and Technologies (CAST), University of Chieti-Pescara, Chieti, Italy.,Department of Pharmacy, University of Chieti-Pescara, Chieti, Italy
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Yu Y, He X, Zhang J, Tang C, Rong P. Transcutaneous auricular vagal nerve stimulation inhibits hypothalamic P2Y1R expression and attenuates weight gain without decreasing food intake in Zucker diabetic fatty rats. Sci Prog 2021; 104:368504211009669. [PMID: 33848220 PMCID: PMC10358456 DOI: 10.1177/00368504211009669] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Zucker diabetic fatty (ZDF) rats that harbor a mutation in the leptin receptor innately develop type 2 diabetes (T2D) with obesity. Transcutaneous auricular vagal nerve stimulation (taVNS) has an antidiabetic effect in ZDF rats. However, the underlying mechanisms of the weight-gain attenuating effect in ZDF rats by taVNS is still unclear. This study aimed to assess whether the weight-gain attenuating effect of taVNS in ZDF rats is associated with changes in the central nervous system (CNS) expression of P2Y1 receptors (P2Y1R). Adult male ZDF rats were subjected to taVNS and transcutaneous non-vagal nerve stimulation (tnVNS). Their food intake and body weight were recorded daily and weekly, respectively. P2Y1R expression in the hypothalamus, amygdala, and hippocampus was evaluated by western blotting. Hypothalamic P2Y1R expressing cells were detected using immunohistochemistry. Naïve ZDF rats were much heavier (p < 0.05) than their lean littermates (ZL rats), with elevated hypothalamic P2Y1R expression (p < 0.05). Further, taVNS but not tnVNS attenuated weight gain (p < 0.05) without decreasing food intake (p > 0.05) and suppressed hypothalamic P2Y1R expression in ZDF rats (p < 0.05). Moreover, P2Y1R showed major expression in astrocytes of ZDF rats' hypothalamus. ZDF rats innately develop obesity associated with elevated hypothalamic P2Y1R expression. taVNS attenuates weight gain in ZDF rats without changes in food intake, suggesting increased energy expenditure. Whether the reduced hypothalamic P2Y1R expression in response to taVNS is mechanistically linked to the increased energy expenditure remains to be determined.
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Affiliation(s)
- Yutian Yu
- Acupuncture Department, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
- Ninth School of Clinical Medicine, Peking University, Beijing, China
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xun He
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jinling Zhang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Chunzhi Tang
- Clinical Medical College of Acupuncture, Moxibustion and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China
| | - Peijing Rong
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
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10
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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: 34] [Impact Index Per Article: 8.5] [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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11
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Teixeira GP, Faria RX. Influence of purinergic signaling on glucose transporters: A possible mechanism against insulin resistance? Eur J Pharmacol 2020; 892:173743. [PMID: 33220279 DOI: 10.1016/j.ejphar.2020.173743] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/04/2020] [Accepted: 11/09/2020] [Indexed: 01/27/2023]
Abstract
Metabolic disorders, such as insulin resistance, affect many people worldwide due to the prevalence of obesity and type 2 diabetes, which are pathologies that impair glycemic metabolism. Glucose is the primary energetic substrate of the body and is essential for cellular function. As the cell membrane is not permeable to glucose molecules, there are two distinct groups of glucose transporters: sodium-glucose-linked transporters (SGLTs) and the glucose transporter (GLUT) family. These transporters facilitate the entry of glucose into the bloodstream or cytoplasm where it functions in the production of adenosine 5 ́-triphosphate (ATP). This nucleotide acts in several cellular mechanisms, such as protein phosphorylation and cellular immune processes. ATP directly and indirectly acts as an agonist for purinergic receptors in high concentrations in the extracellular environment. Composed by P1 and P2 groups, the purinoreceptors cover several cellular mechanisms involving cytokines, tumors, and metabolic signaling pathways. Previous publications have indicated that the purinergic signaling activity in insulin resistance and glucose transporters modulates relevant actions on the deregulations that can affect glycemic homeostasis. Thus, this review focuses on the pharmacological influence of purinergic signaling on the modulation of glucose transporters, aiming for a new way to combat insulin resistance and other metabolic disorders.
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Affiliation(s)
- Guilherme Pegas Teixeira
- Laboratory of Toxoplasmosis and Other Protozoans, Oswaldo Cruz Institute (IOC), Avenida Brasil, 4365, CEP, Rio de Janeiro, Fiocruz, 21040-900, Brazil.
| | - Robson Xavier Faria
- Laboratory of Toxoplasmosis and Other Protozoans, Oswaldo Cruz Institute (IOC), Avenida Brasil, 4365, CEP, Rio de Janeiro, Fiocruz, 21040-900, Brazil.
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12
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Khalafalla MG, Woods LT, Jasmer KJ, Forti KM, Camden JM, Jensen JL, Limesand KH, Galtung HK, Weisman GA. P2 Receptors as Therapeutic Targets in the Salivary Gland: From Physiology to Dysfunction. Front Pharmacol 2020; 11:222. [PMID: 32231563 PMCID: PMC7082426 DOI: 10.3389/fphar.2020.00222] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 02/18/2020] [Indexed: 12/12/2022] Open
Abstract
Although often overlooked in our daily lives, saliva performs a host of necessary physiological functions, including lubricating and protecting the oral cavity, facilitating taste sensation and digestion and maintaining tooth enamel. Therefore, salivary gland dysfunction and hyposalivation, often resulting from pathogenesis of the autoimmune disease Sjögren's syndrome or from radiotherapy of the head and neck region during cancer treatment, severely reduce the quality of life of afflicted patients and can lead to dental caries, periodontitis, digestive disorders, loss of taste and difficulty speaking. Since their initial discovery in the 1970s, P2 purinergic receptors for extracellular nucleotides, including ATP-gated ion channel P2X and G protein-coupled P2Y receptors, have been shown to mediate physiological processes in numerous tissues, including the salivary glands where P2 receptors represent a link between canonical and non-canonical saliva secretion. Additionally, extracellular nucleotides released during periods of cellular stress and inflammation act as a tissue alarmin to coordinate immunological and tissue repair responses through P2 receptor activation. Accordingly, P2 receptors have gained widespread clinical interest with agonists and antagonists either currently undergoing clinical trials or already approved for human use. Here, we review the contributions of P2 receptors to salivary gland function and describe their role in salivary gland dysfunction. We further consider their potential as therapeutic targets to promote physiological saliva flow, prevent salivary gland inflammation and enhance tissue regeneration.
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Affiliation(s)
- Mahmoud G. Khalafalla
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Lucas T. Woods
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Kimberly J. Jasmer
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Kevin Muñoz Forti
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Jean M. Camden
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
| | - Janicke L. Jensen
- Institute of Clinical Dentistry, Section of Oral Surgery and Oral Medicine, University of Oslo, Oslo, Norway
| | - Kirsten H. Limesand
- Department of Nutritional Sciences, University of Arizona, Tucson, AZ, United States
| | - Hilde K. Galtung
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - Gary A. Weisman
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, United States
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13
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Martin-Aragon Baudel M, Espinosa-Tanguma R, Nieves-Cintron M, Navedo MF. Purinergic Signaling During Hyperglycemia in Vascular Smooth Muscle Cells. Front Endocrinol (Lausanne) 2020; 11:329. [PMID: 32528416 PMCID: PMC7256624 DOI: 10.3389/fendo.2020.00329] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 04/28/2020] [Indexed: 12/15/2022] Open
Abstract
The activation of purinergic receptors by nucleotides and/or nucleosides plays an important role in the control of vascular function, including modulation of vascular smooth muscle excitability, and vascular reactivity. Accordingly, purinergic receptor actions, acting as either ion channels (P2X) or G protein-coupled receptors (GCPRs) (P1, P2Y), target diverse downstream effectors, and substrates to regulate vascular smooth muscle function and vascular reactivity. Both vasorelaxant and vasoconstrictive effects have been shown to be mediated by different purinergic receptors in a vascular bed- and species-specific manner. Purinergic signaling has been shown to play a key role in altering vascular smooth muscle excitability and vascular reactivity following acute and short-term elevations in extracellular glucose (e.g., hyperglycemia). Moreover, there is evidence that vascular smooth muscle excitability and vascular reactivity is severely impaired during diabetes and that this is mediated, at least in part, by activation of purinergic receptors. Thus, purinergic receptors present themselves as important candidates mediating vascular reactivity in hyperglycemia, with potentially important clinical and therapeutic potential. In this review, we provide a narrative summarizing our current understanding of the expression, function, and signaling of purinergic receptors specifically in vascular smooth muscle cells and discuss their role in vascular complications following hyperglycemia and diabetes.
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Affiliation(s)
- Miguel Martin-Aragon Baudel
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
- *Correspondence: Miguel Martin-Aragon Baudel
| | - Ricardo Espinosa-Tanguma
- Departamento de Fisiologia y Biofisca, Universidad Autónoma San Luis Potosí, San Luis Potosí, Mexico
| | | | - Manuel F. Navedo
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
- Manuel F. Navedo
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Chen Z, Yuan W, Liu T, Huang D, Xiang L. Bioinformatics analysis of hepatic gene expression profiles in type 2 diabetes mellitus. Exp Ther Med 2019; 18:4303-4312. [PMID: 31772629 PMCID: PMC6861877 DOI: 10.3892/etm.2019.8092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/19/2019] [Indexed: 12/13/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is characterized by hyperglycemia. The liver has a critical role in regulating glucose homeostasis. The present study aimed to analyze hepatic gene expression profiles and to identify the key genes and pathways involved in T2DM. Gene expression profiles of 10 patients with T2DM and 7 subjects with normal glucose tolerance were downloaded from the Gene Expression Omnibus database. Subsequently, differentially expressed genes (DEGs) were identified and functional enrichment analysis was performed. In addition, a protein-protein interaction network was built and hub genes were identified. In total, 1,320 DEGs were identified, including 698 up- and 622 downregulated genes, and these were mainly enriched in positive regulation of transcription from RNA polymerase II promoter, cell adhesion, inflammatory response, positive regulation of apoptotic process, signal transduction and the Tolllike receptor signaling pathway. A total of 8 hub genes (G-protein subunit gamma transducin 2, ubiquitinconjugating enzyme E2 D1, glutamate metabotropic receptor 1, G-protein signaling modulator 1, C-X-C motif chemokine ligand 9, neurotensin, purinergic receptor P2Y1 and ring finger protein 41) were screened from the network. The present study may contribute to the elucidation of the hepatic pathology of T2DM.
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Affiliation(s)
- Zhe Chen
- Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510405, P.R. China
| | - Weiqu Yuan
- The Fourth Clinical Medical School, Guangzhou University of Chinese Medicine, Shenzhen, Guangdong 518033, P.R. China
| | - Tao Liu
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006, P.R. China
| | - Danping Huang
- The Fourth Clinical Medical School, Guangzhou University of Chinese Medicine, Shenzhen, Guangdong 518033, P.R. China
| | - Lei Xiang
- Department of Integrative Chinese and Western Medicine, The First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou, Guangdong 510080, P.R. China
- Correspondence to: Dr Lei Xiang, Department of Integrative Chinese and Western Medicine, The First Affiliated Hospital of Guangdong Pharmaceutical University, 19 Nonglinxia Road, Guangzhou, Guangdong 510080, P.R. China, E-mail:
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15
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Bauer C, Kaiser J, Sikimic J, Krippeit-Drews P, Düfer M, Drews G. ATP mediates a negative autocrine signal on stimulus-secretion coupling in mouse pancreatic β-cells. Endocrine 2019; 63:270-283. [PMID: 30229397 DOI: 10.1007/s12020-018-1731-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 08/20/2018] [Indexed: 02/07/2023]
Abstract
PURPOSE The role of ATP, which is secreted by pancreatic β-cells, is still a matter of debate. It has been postulated that extracellular ATP acts as a positive auto- or paracrine signal in β-cells amplifying insulin secretion. However, there is rising evidence that extracellular ATP may also mediate a negative signal. METHODS We evaluated whether extracellular ATP interferes with the Ca2+-mediated negative feedback mechanism that regulates oscillatory activity of β-cells. RESULTS To experimentally uncover the Ca2+-induced feedback we applied a high extracellular Ca2+ concentration. Under this condition ATP (100 µM) inhibited glucose-evoked oscillations of electrical activity and hyperpolarized the membrane potential. Furthermore, ATP acutely increased the interburst phase of Ca2+ oscillations and reduced the current through L-type Ca2+ channels. Accordingly, ATP (500 µM) decreased glucose-induced insulin secretion. The ATP effect was not mimicked by AMP, ADP, or adenosine. The use of specific agonists and antagonists and mice deficient of large conductance Ca2+-dependent K+ channels revealed that P2X, but not P2Y receptors, and Ca2+-dependent K+ channels are involved in the underlying signaling cascade induced by ATP. The effectiveness of ATP to interfere with parameters of stimulus-secretion coupling is markedly reduced at low extracellular Ca2+ concentration. CONCLUSION It is suggested that extracellular ATP which is co-secreted with insulin in a pulsatile manner during glucose-stimulated exocytosis provides a negative feedback signal driving β-cell oscillations in co-operation with Ca2+ and other signals.
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Affiliation(s)
- Cita Bauer
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen, D-72076, Germany
| | - Julia Kaiser
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen, D-72076, Germany
| | - Jelena Sikimic
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen, D-72076, Germany
| | - Peter Krippeit-Drews
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen, D-72076, Germany
| | - Martina Düfer
- Department of Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstraße 48, Münster, D-48149, Germany
| | - Gisela Drews
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen, D-72076, Germany.
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16
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Skelin Klemen M, Dolenšek J, Slak Rupnik M, Stožer A. The triggering pathway to insulin secretion: Functional similarities and differences between the human and the mouse β cells and their translational relevance. Islets 2017; 9:109-139. [PMID: 28662366 PMCID: PMC5710702 DOI: 10.1080/19382014.2017.1342022] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In β cells, stimulation by metabolic, hormonal, neuronal, and pharmacological factors is coupled to secretion of insulin through different intracellular signaling pathways. Our knowledge about the molecular machinery supporting these pathways and the patterns of signals it generates comes mostly from rodent models, especially the laboratory mouse. The increased availability of human islets for research during the last few decades has yielded new insights into the specifics in signaling pathways leading to insulin secretion in humans. In this review, we follow the most central triggering pathway to insulin secretion from its very beginning when glucose enters the β cell to the calcium oscillations it produces to trigger fusion of insulin containing granules with the plasma membrane. Along the way, we describe the crucial building blocks that contribute to the flow of information and focus on their functional role in mice and humans and on their translational implications.
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Affiliation(s)
- Maša Skelin Klemen
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Jurij Dolenšek
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Marjan Slak Rupnik
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Institute of Physiology; Center for Physiology and Pharmacology; Medical University of Vienna; Vienna, Austria
| | - Andraž Stožer
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
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17
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Molecular regulation of insulin granule biogenesis and exocytosis. Biochem J 2017; 473:2737-56. [PMID: 27621482 DOI: 10.1042/bcj20160291] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 04/19/2016] [Indexed: 12/15/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by hyperglycemia, insulin resistance and hyperinsulinemia in early disease stages but a relative insulin insufficiency in later stages. Insulin, a peptide hormone, is produced in and secreted from pancreatic β-cells following elevated blood glucose levels. Upon its release, insulin induces the removal of excessive exogenous glucose from the bloodstream primarily by stimulating glucose uptake into insulin-dependent tissues as well as promoting hepatic glycogenesis. Given the increasing prevalence of T2DM worldwide, elucidating the underlying mechanisms and identifying the various players involved in the synthesis and exocytosis of insulin from β-cells is of utmost importance. This review summarizes our current understanding of the route insulin takes through the cell after its synthesis in the endoplasmic reticulum as well as our knowledge of the highly elaborate network that controls insulin release from the β-cell. This network harbors potential targets for anti-diabetic drugs and is regulated by signaling cascades from several endocrine systems.
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18
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Abstract
Type 1 diabetes (T1D) patients who receive pancreatic islet transplant experience significant improvement in their quality-of-life. This comes primarily through improved control of blood sugar levels, restored awareness of hypoglycemia, and prevention of serious and potentially life-threatening diabetes-associated complications, such as kidney failure, heart and vascular disease, stroke, nerve damage, and blindness. Therefore, beta cell replacement through transplantation of isolated islets is an important option in the treatment of T1D. However, lasting success of this promising therapy depends on durable survival and efficacy of the transplanted islets, which are directly influenced by the islet isolation procedures. Thus, isolating pancreatic islets with consistent and reliable quality is critical in the clinical application of islet transplantation.Quality of isolated islets is important in pre-clinical studies as well, as efforts to advance and improve clinical outcomes of islet transplant therapy have relied heavily on animal models ranging from rodents, to pigs, to nonhuman primates. As a result, pancreatic islets have been isolated from these and other species and used in a variety of in vitro or in vivo applications for this and other research purposes. Protocols for islet isolation have been somewhat similar across species, especially, in mammals. However, given the increasing evidence about the distinct structural and functional features of human and mouse islets, using similar methods of islet isolation may contribute to inconsistencies in the islet quality, immunogenicity, and experimental outcomes. This may also contribute to the discrepancies commonly observed between pre-clinical findings and clinical outcomes. Therefore, it is prudent to consider the particular features of pancreatic islets from different species when optimizing islet isolation protocols.In this chapter, we explore the structural and functional features of pancreatic islets from mice, pigs, nonhuman primates, and humans because of their prevalent use in nonclinical, preclinical, and clinical applications.
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19
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Maciel RM, Carvalho FB, Olabiyi AA, Schmatz R, Gutierres JM, Stefanello N, Zanini D, Rosa MM, Andrade CM, Rubin MA, Schetinger MR, Morsch VM, Danesi CC, Lopes STA. Neuroprotective effects of quercetin on memory and anxiogenic-like behavior in diabetic rats: Role of ectonucleotidases and acetylcholinesterase activities. Biomed Pharmacother 2016; 84:559-568. [PMID: 27694000 DOI: 10.1016/j.biopha.2016.09.069] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 09/13/2016] [Accepted: 09/19/2016] [Indexed: 11/24/2022] Open
Abstract
The present study investigated the protective effect of quercetin (Querc) on memory, anxiety-like behavior and impairment of ectonucleotidases and acetylcholinesterase (AChE) activities in brain of streptozotocin-induced diabetic rats (STZ-diabetes). The type 1 diabetes mellitus was induced by an intraperitoneal injection of 70mg/kg of streptozotocin (STZ), diluted in 0.1M sodium-citrate buffer (pH 4.5). Querc was dissolved in 25% ethanol and administered by gavage at the doses of 5, 25 and 50mg/kg once a day during 40days. The animals were distributed in eight groups of ten animals as follows: vehicle, Querc 5mg/kg, Querc 25mg/kg, Querc 50mg/kg, diabetes, diabetes plus Querc 5mg/kg, diabetes plus Querc 25mg/kg and diabetes plus Querc 50mg/kg. Querc was able to prevent the impairment of memory and the anxiogenic-like behavior induced by STZ-diabetes. In addition, Querc prevents the decrease in the NTPDase and increase in the adenosine deaminase (ADA) activities in SN from cerebral cortex of STZ-diabetes. STZ-diabetes increased the AChE activity in SN from cerebral cortex and hippocampus. Querc 50mg/kg was more effective to prevent the increase in AChE activity in the brain of STZ-diabetes. Querc also prevented an increase in the malondialdehyde levels in all the brain structures. In conclusion, the present findings showed that Querc could prevent the impairment of the enzymes that regulate the purinergic and cholinergic extracellular signaling and improve the memory and anxiety-like behavior induced by STZ-diabetes.
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Affiliation(s)
- Roberto M Maciel
- Programa de Pós-Graduação em Medicina Veterinária, Laboratório de Análises Clínicas Veterinária, Centro de Ciências Rurais, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil
| | - Fabiano B Carvalho
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil.
| | - Ayodeji A Olabiyi
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil; Department of Medical Biochemistry, Afe Babalola University, Ado Ekiti, P.M.B 5454. Ado Ekiti, Nigeria
| | - Roberta Schmatz
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil
| | - Jessié M Gutierres
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil
| | - Naiara Stefanello
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil
| | - Daniela Zanini
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil
| | - Michelle M Rosa
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil
| | - Cinthia M Andrade
- Programa de Pós-Graduação em Medicina Veterinária, Laboratório de Análises Clínicas Veterinária, Centro de Ciências Rurais, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil
| | - Maribel A Rubin
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil
| | - Maria Rosa Schetinger
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil
| | - Vera Maria Morsch
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil
| | - Cristiane C Danesi
- Programa de Pós-Graduação em Ciências Odontológicas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Sonia T A Lopes
- Programa de Pós-Graduação em Medicina Veterinária, Laboratório de Análises Clínicas Veterinária, Centro de Ciências Rurais, Universidade Federal de Santa Maria, Santa Maria/RS 97105-900, Brazil.
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Zimmermann H. Extracellular ATP and other nucleotides-ubiquitous triggers of intercellular messenger release. Purinergic Signal 2015; 12:25-57. [PMID: 26545760 DOI: 10.1007/s11302-015-9483-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 10/29/2015] [Indexed: 12/21/2022] Open
Abstract
Extracellular nucleotides, and ATP in particular, are cellular signal substances involved in the control of numerous (patho)physiological mechanisms. They provoke nucleotide receptor-mediated mechanisms in select target cells. But nucleotides can considerably expand their range of action. They function as primary messengers in intercellular communication by stimulating the release of other extracellular messenger substances. These in turn activate additional cellular mechanisms through their own receptors. While this applies also to other extracellular messengers, its omnipresence in the vertebrate organism is an outstanding feature of nucleotide signaling. Intercellular messenger substances released by nucleotides include neurotransmitters, hormones, growth factors, a considerable variety of other proteins including enzymes, numerous cytokines, lipid mediators, nitric oxide, and reactive oxygen species. Moreover, nucleotides activate or co-activate growth factor receptors. In the case of hormone release, the initially paracrine or autocrine nucleotide-mediated signal spreads through to the entire organism. The examples highlighted in this commentary suggest that acting as ubiquitous triggers of intercellular messenger release is one of the major functional roles of extracellular nucleotides. While initiation of messenger release by nucleotides has been unraveled in many contexts, it may have been overlooked in others. It can be anticipated that additional nucleotide-driven messenger functions will be uncovered with relevance for both understanding physiology and development of therapy.
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Affiliation(s)
- Herbert Zimmermann
- Institute of Cell Biology and Neuroscience, Molecular and Cellular Neurobiology, Goethe University, Max-von-Laue-Str. 13, Frankfurt am Main, Germany.
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Arrojo e Drigo R, Ali Y, Diez J, Srinivasan DK, Berggren PO, Boehm BO. New insights into the architecture of the islet of Langerhans: a focused cross-species assessment. Diabetologia 2015. [PMID: 26215305 DOI: 10.1007/s00125-015-3699-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The human genome project and its search for factors underlying human diseases has fostered a major human research effort. Therefore, unsurprisingly, in recent years we have observed an increasing number of studies on human islet cells, including disease approaches focusing on type 1 and type 2 diabetes. Yet, the field of islet and diabetes research relies on the legacy of rodent-based investigations, which have proven difficult to translate to humans, particularly in type 1 diabetes. Whole islet physiology and pathology may differ between rodents and humans, and thus a comprehensive cross-species as well as species-specific view on islet research is much needed. In this review we summarise the current knowledge of interspecies islet cytoarchitecture, and discuss its potential impact on islet function and future perspectives in islet pathophysiology research.
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Affiliation(s)
- Rafael Arrojo e Drigo
- Lee Kong Chian School of Medicine, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, Level 4, 637 553, Singapore, Singapore
| | - Yusuf Ali
- Lee Kong Chian School of Medicine, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, Level 4, 637 553, Singapore, Singapore
| | - Juan Diez
- Lee Kong Chian School of Medicine, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, Level 4, 637 553, Singapore, Singapore
| | - Dinesh Kumar Srinivasan
- Lee Kong Chian School of Medicine, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, Level 4, 637 553, Singapore, Singapore
| | - Per-Olof Berggren
- Lee Kong Chian School of Medicine, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, Level 4, 637 553, Singapore, Singapore.
- Imperial College London, London, UK.
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska University Hospital L1, Karolinska Institutet, SE-171 76, Stockholm, Sweden.
| | - Bernhard O Boehm
- Lee Kong Chian School of Medicine, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, Level 4, 637 553, Singapore, Singapore.
- Imperial College London, London, UK.
- Department of Internal Medicine 1, Ulm University Medical Centre, Ulm, Germany.
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Todd JN, Poon W, Lyssenko V, Groop L, Nichols B, Wilmot M, Robson S, Enjyoji K, Herman MA, Hu C, Zhang R, Jia W, Ma R, Florez JC, Friedman DJ. Variation in glucose homeostasis traits associated with P2RX7 polymorphisms in mice and humans. J Clin Endocrinol Metab 2015; 100:E688-96. [PMID: 25719930 PMCID: PMC4422893 DOI: 10.1210/jc.2014-4160] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
CONTEXT Extracellular nucleotide receptors are expressed in pancreatic B-cells. Purinergic signaling via these receptors may regulate pancreatic B-cell function. OBJECTIVE We hypothesized that purinergic signaling might influence glucose regulation and sought evidence in human studies of glycemic variation and a mouse model of purinergic signaling dysfunction. DESIGN In humans, we mined genome-wide meta-analysis data sets to examine purinergic signaling genes for association with glycemic traits and type 2 diabetes. We performed additional testing in two genomic regions (P2RX4/P2RX7 and P2RY1) in a cohort from the Prevalence, Prediction, and Prevention of Diabetes in Botnia (n = 3504), which includes more refined measures of glucose homeostasis. In mice, we generated a congenic model of purinergic signaling dysfunction by crossing the naturally hypomorphic C57BL6 P2rx7 allele onto the 129SvJ background. RESULTS Variants in five genes were associated with glycemic traits and in three genes with diabetes risk. In the Prevalence, Prediction, and Prevention of Diabetes in Botnia study, the minor allele in the missense functional variant rs1718119 (A348T) in P2RX7 was associated with increased insulin sensitivity and secretion, consistent with its known effect on increased pore function. Both male and female P2x7-C57 mice demonstrated impaired glucose tolerance compared with matched P2x7-129 mice. Insulin tolerance testing showed that P2x7-C57 mice were also less responsive to insulin than P2x7-129 mice. CONCLUSIONS We show association of the purinergic signaling pathway in general and hypofunctioning P2X7 variants in particular with impaired glucose homeostasis in both mice and humans.
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Affiliation(s)
- Jennifer N Todd
- Division of Endocrinology (J.N.T.), Boston Children's Hospital, and Departments of Pediatrics (J.N.T.) and Medicine (S.R., K.E., M.A.H., J.C.F., D.J.F.), Harvard Medical School, and Department of Medicine (B.N., M.W., S.R., K.E., M.A.H., D.J.F.) and Center for Vascular Biology Research (B.N., M.W., D.J.F.), Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115; Center for Human Genetic Research (J.N.T., J.C.F.), and Diabetes Research Center (Diabetes Unit) (J.C.F.), Massachusetts General Hospital, Boston, Massachusetts 02114; Program in Medical and Population Genetics (J.C.F.), Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142; Department of Clinical Sciences, Diabetes, and Endocrinology (W.P., V.L., L.G.), Skåne University Hospital, Lund University, SE 205 02 Malmö, Sweden; Department of Translational Pathophysiology (V.L.), Steno Diabetes Center A/S, DK-2820 Gentofte, Denmark; Institute for Molecular Medicine Finland FIMM (L.G.), University of Helsinki, FI-00014 Helsinki, Finland; Shanghai Jiao Tong University Affiliated Sixth People's Hospital (C.H., R.Z., W.J.), Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai 200233, China; and Department of Medicine and Therapeutics (R.M.), Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong
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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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Khan S, Yan-Do R, Duong E, Wu X, Bautista A, Cheley S, MacDonald PE, Braun M. Autocrine activation of P2Y1 receptors couples Ca (2+) influx to Ca (2+) release in human pancreatic beta cells. Diabetologia 2014; 57:2535-45. [PMID: 25208758 DOI: 10.1007/s00125-014-3368-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 08/13/2014] [Indexed: 01/26/2023]
Abstract
AIMS/HYPOTHESIS There is evidence that ATP acts as an autocrine signal in beta cells but the receptors and pathways involved are incompletely understood. Here we investigate the receptor subtype(s) and mechanism(s) mediating the effects of ATP on human beta cells. METHODS We examined the effects of purinergic agonists and antagonists on membrane potential, membrane currents, intracellular Ca(2+) ([Ca(2+)]i) and insulin secretion in human beta cells. RESULTS Extracellular application of ATP evoked small inward currents (3.4 ± 0.7 pA) accompanied by depolarisation of the membrane potential (by 14.4 ± 2.4 mV) and stimulation of electrical activity at 6 mmol/l glucose. ATP increased [Ca(2+)]i by stimulating Ca(2+) influx and evoking Ca(2+) release via InsP3-receptors in the endoplasmic reticulum (ER). ATP-evoked Ca(2+) release was sufficient to trigger exocytosis in cells voltage-clamped at -70 mV. All effects of ATP were mimicked by the P2Y(1/12/13) agonist ADP and the P2Y1 agonist MRS-2365, whereas the P2X(1/3) agonist α,β-methyleneadenosine-5-triphosphate only had a small effect. The P2Y1 antagonists MRS-2279 and MRS-2500 hyperpolarised glucose-stimulated beta cells and lowered [Ca(2+)]i in the absence of exogenously added ATP and inhibited glucose-induced insulin secretion by 35%. In voltage-clamped cells subjected to action potential-like stimulation, MRS-2279 decreased [Ca(2+)]i and exocytosis without affecting Ca(2+) influx. CONCLUSIONS/INTERPRETATION These data demonstrate that ATP acts as a positive autocrine signal in human beta cells by activating P2Y1 receptors, stimulating electrical activity and coupling Ca(2+) influx to Ca(2+) release from ER stores.
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Affiliation(s)
- Shara Khan
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
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25
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Sakamoto S, Miyaji T, Hiasa M, Ichikawa R, Uematsu A, Iwatsuki K, Shibata A, Uneyama H, Takayanagi R, Yamamoto A, Omote H, Nomura M, Moriyama Y. Impairment of vesicular ATP release affects glucose metabolism and increases insulin sensitivity. Sci Rep 2014; 4:6689. [PMID: 25331291 PMCID: PMC4204045 DOI: 10.1038/srep06689] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 09/17/2014] [Indexed: 12/04/2022] Open
Abstract
Neuroendocrine cells store ATP in secretory granules and release it along with hormones that may trigger a variety of cellular responses in a process called purinergic chemical transmission. Although the vesicular nucleotide transporter (VNUT) has been shown to be involved in vesicular storage and release of ATP, its physiological relevance in vivo is far less well understood. In Vnut knockout (Vnut(-/-)) mice, we found that the loss of functional VNUT in adrenal chromaffin granules and insulin granules in the islets of Langerhans led to several significant effects. Vesicular ATP accumulation and depolarization-dependent ATP release were absent in the chromaffin granules of Vnut(-/-) mice. Glucose-responsive ATP release was also absent in pancreatic β-cells in Vnut(-/-) mice, while glucose-responsive insulin secretion was enhanced to a greater extent than that in wild-type tissue. Vnut(-/-) mice exhibited improved glucose tolerance and low blood glucose upon fasting due to increased insulin sensitivity. These results demonstrated an essential role of VNUT in vesicular storage and release of ATP in neuroendocrine cells in vivo and suggest that vesicular ATP and/or its degradation products act as feedback regulators in catecholamine and insulin secretion, thereby regulating blood glucose homeostasis.
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Affiliation(s)
- Shohei Sakamoto
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, JAPAN
| | - Takaaki Miyaji
- Advanced Research Science Center, Okayama University, Okayama 700-8530, JAPAN
| | - Miki Hiasa
- Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8530, JAPAN
| | - Reiko Ichikawa
- Institute for Innovation, Ajinomoto Co., Inc. Kawasaki 210-5893, JAPAN
| | - Akira Uematsu
- Institute for Innovation, Ajinomoto Co., Inc. Kawasaki 210-5893, JAPAN
| | - Ken Iwatsuki
- Institute for Innovation, Ajinomoto Co., Inc. Kawasaki 210-5893, JAPAN
| | - Atsushi Shibata
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, JAPAN
| | - Hisayuki Uneyama
- Institute for Innovation, Ajinomoto Co., Inc. Kawasaki 210-5893, JAPAN
| | - Ryoichi Takayanagi
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, JAPAN
| | - Akitsugu Yamamoto
- Faculty of Bioscience, Nagahama Institute of Bio-science and Technology, Nagahama 526-0829, JAPAN
| | - Hiroshi Omote
- Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8530, JAPAN
| | - Masatoshi Nomura
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, JAPAN
| | - Yoshinori Moriyama
- Advanced Research Science Center, Okayama University, Okayama 700-8530, JAPAN
- Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8530, JAPAN
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26
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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: 58] [Impact Index Per Article: 5.8] [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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27
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Abdulreda MH, Caicedo A, Berggren PO. A NATURAL BODY WINDOW TO STUDY HUMAN PANCREATIC ISLET CELL FUNCTION AND SURVIVAL. CELLR4-- REPAIR, REPLACEMENT, REGENERATION, & REPROGRAMMING 2013; 1:111-122. [PMID: 29497630 PMCID: PMC5828509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The World Health Organization projects diabetes prevalence worldwide to be at 4.4% in 2030 compared to 2.8% in the year 2000. These alarming predictions come amid vigorous efforts in diabetes research which have failed so far to deliver effective therapies. Our incomplete understanding of the pathogenesis of diabetes is likely to contribute to the "disconnect" between our research efforts and their translation into successful therapies. Technically, studying the pathophysiology of the pancreatic islets is hindered by the anatomical location of the pancreas, which is deeply embedded in the body, and by lack of experimental tools that enable comprehensive interrogation of the pancreatic islets with sufficient resolution in the context of the natural in vivo environment non-invasively and longitudinally. Emerging evidence also indicates that challenges in successful translation of findings in animal models to the human setting are complicated by some inherent structural and functional differences between the mouse and human islets. In this review, we briefly describe the advantages and shortcomings of existing intravital imaging approaches used to study the pancreatic islet biology in vivo, and we contrast such techniques with a recently established intravital approach using pancreatic islet transplantation into the anterior chamber of the eye. We also provide a summary of recent structure-function studies in the human pancreas to reveal distinctive features of human islets compared with mouse islets. We finally touch on a recently renewed discussion of the validity of animal models in studying human health and disease, and we highlight the potential utility of "humanized" animal models in studying different aspects of human islet biology and improving our understanding of diabetes.
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Affiliation(s)
- M H Abdulreda
- Diabetes Research Institute, Diabetes Research Institute Federation Center at the University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - A Caicedo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL, USA
- Program in Neuroscience, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - P-O Berggren
- Diabetes Research Institute, Diabetes Research Institute Federation Center at the University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
- Rolf Luft Research Center for Diabetes & Endocrinology, Diabetes Research Institute Federation Center at Karolinska Institutet, Stockholm, SE, Sweden
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Abstract
The pancreas is an organ with a central role in nutrient breakdown, nutrient sensing and release of hormones regulating whole body nutrient homeostasis. In diabetes mellitus, the balance is broken-cells can be starving in the midst of plenty. There are indications that the incidence of diabetes type 1 and 2, and possibly pancreatogenic diabetes, is rising globally. Events leading to insulin secretion and action are complex, but there is emerging evidence that intracellular nucleotides and nucleotides are not only important as intracellular energy molecules but also as extracellular signalling molecules in purinergic signalling cascades. This signalling takes place at the level of the pancreas, where the close apposition of various cells-endocrine, exocrine, stromal and immune cells-contributes to the integrated function. Following an introduction to diabetes, the pancreas and purinergic signalling, we will focus on the role of purinergic signalling and its changes associated with diabetes in the pancreas and selected tissues/organ systems affected by hyperglycaemia and other stress molecules of diabetes. Since this is the first review of this kind, a comprehensive historical angle is taken, and common and divergent roles of receptors for nucleotides and nucleosides in different organ systems will be given. This integrated picture will aid our understanding of the challenges of the potential and currently used drugs targeted to specific organ/cells or disorders associated with diabetes.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF UK
- Department of Pharmacology, Melbourne University, Melbourne, Australia
| | - Ivana Novak
- Molecular and Integrative Physiology, Department of Biology, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100 Copenhagen Ø, Denmark
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Geisler JC, Corbin KL, Li Q, Feranchak AP, Nunemaker CS, Li C. Vesicular nucleotide transporter-mediated ATP release regulates insulin secretion. Endocrinology 2013; 154:675-84. [PMID: 23254199 PMCID: PMC3548185 DOI: 10.1210/en.2012-1818] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Extracellular ATP plays a critical role in regulating insulin secretion in pancreatic β cells. The ATP released from insulin secretory vesicles has been proposed to be a major source of extracellular ATP. Currently, the mechanism by which ATP accumulates into insulin secretory granules remains elusive. In this study, the authors identified the expression of a vesicular nucleotide transporter (VNUT) in mouse pancreas, isolated mouse islets, and MIN6 cells, a mouse β cell line. Immunohistochemistry and immunofluorescence revealed that VNUT colocalized extensively with insulin secretory granules. Functional studies showed that suppressing endogenous VNUT expression in β cells by small hairpin RNA knockdown greatly reduced basal- and glucose-induced ATP release. Importantly, knocking down VNUT expression by VNUT small hairpin RNA in MIN6 cells and isolated mouse islets dramatically suppressed basal insulin release and glucose-stimulated insulin secretion (GSIS). Moreover, acute pharmacologic blockade of VNUT with Evans blue, a VNUT antagonist, greatly attenuated GSIS in a dose-dependent manner. Exogenous ATP treatment effectively reversed the insulin secretion defect induced by both VNUT knockdown and functional inhibition, indicating that VNUT-mediated ATP release is essential for maintaining normal insulin secretion. In contrast to VNUT knockdown, overexpression of VNUT in β cells resulted in excessive ATP release and enhanced basal insulin secretion and GSIS. Elevated insulin secretion induced by VNUT overexpression was reversed by pharmacologic inhibition of P2X but not P2Y purinergic receptors. This study reveals VNUT is expressed in pancreatic β cells and plays an essential and novel role in regulating insulin secretion through vesicular ATP release and extracellular purinergic signaling.
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Affiliation(s)
- Jessica C Geisler
- Department of Pharmacology, University of Virginia Health System, Charlottesville, VA 22908, USA
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Wuttke A, Idevall-Hagren O, Tengholm A. P2Y₁ receptor-dependent diacylglycerol signaling microdomains in β cells promote insulin secretion. FASEB J 2013; 27:1610-20. [PMID: 23299857 DOI: 10.1096/fj.12-221499] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Diacylglycerol (DAG) controls numerous cell functions by regulating the localization of C1-domain-containing proteins, including protein kinase C (PKC), but little is known about the spatiotemporal dynamics of the lipid. Here, we explored plasma membrane DAG dynamics in pancreatic β cells and determined whether DAG signaling is involved in secretagogue-induced pulsatile release of insulin. Single MIN6 cells, primary mouse β cells, and human β cells within intact islets were transfected with translocation biosensors for DAG, PKC activity, or insulin secretion and imaged with total internal reflection fluorescence microscopy. Muscarinic receptor stimulation triggered stable, homogenous DAG elevations, whereas glucose induced short-lived (7.1 ± 0.4 s) but high-amplitude elevations (up to 109 ± 10% fluorescence increase) in spatially confined membrane regions. The spiking was mimicked by membrane depolarization and suppressed after inhibition of exocytosis or of purinergic P2Y₁, but not P2X receptors, reflecting involvement of autocrine purinoceptor activation after exocytotic release of ATP. Each DAG spike caused local PKC activation with resulting dissociation of its substrate protein MARCKS from the plasma membrane. Inhibition of spiking reduced glucose-induced pulsatile insulin secretion. Thus, stimulus-specific DAG signaling patterns appear in the plasma membrane, including distinct microdomains, which have implications for the kinetic control of exocytosis and other membrane-associated processes.
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Affiliation(s)
- Anne Wuttke
- Department of Medical Cell Biology, Uppsala University, Biomedical Centre, Uppsala, Sweden
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31
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Barker CJ, Leibiger IB, Berggren PO. The pancreatic islet as a signaling hub. Adv Biol Regul 2013; 53:156-163. [PMID: 23073565 DOI: 10.1016/j.jbior.2012.09.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 09/24/2012] [Indexed: 06/01/2023]
Abstract
Over the last two decades we have focused on beta cell signal transduction, bringing many new insights, especially in the context of insulin signal transduction, the role of inositol polyphosphates and the regulation of cytoplasmic free Ca(2+) concentration. However, there has been a growing awareness that the beta cell, which is mandatory for insulin secretion, has a unique context within the micro-organ of the pancreatic Islet of Langerhans. In this environment the beta cell both mediates and receives paracrine regulation, critical for the control of blood glucose homeostasis. Failure of an appropriate beta cell function leads to the development of diabetes mellitus. In our quest to understand the molecular events maintaining beta cell function we have faced two key challenges. Firstly, whilst there are many similarities between signal transduction in pancreatic islets between the much used rodent models and humans there are some notable differences. Critical distinctions between rodent and primate can be made in the structure of the islet, including the arrangement of the islet cells, the innervation pattern and the microcirculation. This means that important signaling interactions between islets cells, mediated through for example insulin, glucagon, GABA, glutamate and ATP, will have a unique human framework. The second challenge was to be able to take the discoveries we have made using in vitro systems and examine them in an in vivo context. Advances in in vivo imaging achieved by utilizing the anterior chamber of the eye as a transplantation site for pancreatic islets make it possible for non-invasive, longitudinal studies at single cell resolution in real time of islet cell physiology and pathology. Thus it is becoming possible to study the insulin secreting pancreatic beta cell within the framework of the unique micro-organ, the Islet of Langerhans, for the first time in a physiological context, i.e. when being innervated and connected to the blood supply.
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Affiliation(s)
- Christopher J Barker
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden
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The CD39-adenosinergic axis in the pathogenesis of immune and nonimmune diabetes. J Biomed Biotechnol 2012; 2012:320495. [PMID: 23118504 PMCID: PMC3480695 DOI: 10.1155/2012/320495] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 07/27/2012] [Indexed: 11/24/2022] Open
Abstract
Diabetes mellitus encompasses two distinct disease processes: autoimmune Type 1 (T1D) and nonimmune Type 2 (T2D) diabetes. Despite the disparate aetiologies, the disease phenotype of hyperglycemia and the associated complications are similar. In this paper, we discuss the role of the CD39-adenosinergic axis in the pathogenesis of both T1D and T2D, with particular emphasis on the role of CD39 and CD73.
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Caicedo A. Paracrine and autocrine interactions in the human islet: more than meets the eye. Semin Cell Dev Biol 2012; 24:11-21. [PMID: 23022232 DOI: 10.1016/j.semcdb.2012.09.007] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 09/19/2012] [Indexed: 12/20/2022]
Abstract
The pancreatic islet secretes the hormones insulin and glucagon to regulate glucose metabolism. To generate an adequate secretory response, islet endocrine cells must receive multiple regulatory signals relaying information about changes in the internal and external environments. Islet cells also need to be made aware about the functional status of neighboring cells through paracrine interactions. All this information is used to orchestrate a hormonal response that contributes to glucose homeostasis. Several neurotransmitters have been proposed to work as paracrine signals in the islet. Most of these, however, have yet to meet the criteria to be considered bona fide paracrine signals, in particular in human islets. Here, we review recent findings describing autocrine and paracrine signaling mechanisms in human islets. These recent results are showing an increasingly complex picture of paracrine interactions in the human islet and emphasize that results from other species cannot be readily extrapolated to the human context. Investigators are unveiling new signaling mechanisms or finding new roles for known paracrine signals in human islets. While it is too early to provide a synthesis, the field of islet research is defining the paracrine and autocrine components that will be used to generate models about how islet function is regulated. Meanwhile, the identified signaling pathways can be proposed as therapeutic targets for treating diabetes, a devastating disease affecting millions worldwide.
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Affiliation(s)
- Alejandro Caicedo
- Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
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Yelovitch S, Barr HM, Camden J, Weisman GA, Shai E, Varon D, Fischer B. Identification of a promising drug candidate for the treatment of type 2 diabetes based on a P2Y(1) receptor agonist. J Med Chem 2012; 55:7623-35. [PMID: 22873688 PMCID: PMC4354947 DOI: 10.1021/jm3006355] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The activation by extracellular nucleotides of pancreatic P2Y receptors, particularly, the P2Y(1)R subtype, increases insulin secretion. Therefore, we developed analogues of the P2Y(1)R receptor agonist 2-MeS-ADP, as potential antidiabetic drugs. Analogue 3A was found to be a potent P2Y(1)R agonist (EC(50) = 0.038 μM vs 0.0025 μM for 2-MeS-ADP) showing no activity at P2Y(2/4/6)Rs. Analogue 3A was stable at pH 1.4 (t(1/2) = 7.3 h) and resistant to hydrolysis vs 2-MeS-ADP by alkaline phosphatase (t(1/2) = 6 vs 4.5 h), human e-NPP1 (4% vs 16% hydrolysis after 20 min), and human blood serum (30% vs 50% hydrolysis after 24 h). Intravenous administration of 3A in naive rats decreased blood glucose from 155 mg/dL to normal values, ca. 87 mg/dL, unlike glibenclamide, leading to subnormal values (i.e., 63 mg/dL). Similar observations were made for streptozotocin (STZ)-treated and db(+)/db(-) mouse models. Furthermore, 3A inhibits platelet aggregation in vitro and elongates bleeding time in mice (iv administration of 30 mg of 3A/kg), increasing bleeding time to 16 vs 9 min for Prasugrel. Oral administration of 30 mg/kg 3A to rats increased tail bleeding volume, similar to aspirin. These findings suggest that 3A may be an effective treatment for type 2 diabetes by reducing both blood glucose levels and platelet aggregation.
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Affiliation(s)
- Shir Yelovitch
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Haim M. Barr
- BioLlneRx Ltd., 23 Hillel Street, Jerusalem 91450, Israel
| | - Jean Camden
- Biochemistry Department, 540E Bond Life Sciences Center, University of Nlissouri, Colwnbia, Nlissouri 65211, United States
| | - Gary A Weisman
- Biochemistry Department, 540E Bond Life Sciences Center, University of Nlissouri, Colwnbia, Nlissouri 65211, United States
| | - Ela Shai
- Department of Hematology, Hadassah University Hospital, Jerusalem 91120, Israel
| | - David Varon
- Department of Hematology, Hadassah University Hospital, Jerusalem 91120, Israel
| | - Bilha Fischer
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
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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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Tanaka S, Kudo H, Asari T, Ono A, Motomura S, Toh S, Furukawa KI. P2Y1 transient overexpression induced mineralization in spinal ligament cells derived from patients with ossification of the posterior longitudinal ligament of the cervical spine. Calcif Tissue Int 2011; 88:263-71. [PMID: 21210088 DOI: 10.1007/s00223-010-9456-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 12/12/2010] [Indexed: 12/01/2022]
Abstract
Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic bone formation in the spinal ligaments. We previously reported that P2 purinoceptor Y1 (P2Y1) expression is elevated in the spinal ligament cells of OPLL patients, but the role of P2Y1 in the spinal ligament calcification process is unknown. To verify the hypothesis that P2Y1 expression causes ossification of the spinal ligaments, we forced expression of P2Y1 in spinal ligament cells obtained from OPLL and non-OPLL patients using a cytomegaloviral vector. The expression of mRNA and protein was investigated by quantitative real-time polymerase chain reaction and immunofluorescence staining, respectively. After transfection, bone morphogenetic protein-2 (BMP-2) and Sox9 mRNA expression was significantly increased in spinal ligament cells derived from OPLL patients (4.36- and 6.44-fold, respectively) compared with cells from non-OPLL patients (0.57- and 3.64-fold, respectively) 2 days after P2Y1 transient transfection. Furthermore, a statistically significant correlation was observed between BMP-2 and P2Y1 mRNA expression levels in cells obtained from OPLL patients but not from non-OPLL patients. Immunofluorescence analysis showed that BMP-2 and P2Y1 expression was increased in OPLL patients only, while Sox9 expression was increased in OPLL and non-OPLL patients. MRS2279, a selective P2Y1 antagonist, blocked the upregulation of Sox9 and BMP-2 after forced expression of P2Y1. Furthermore, 4 days after transient transfection of P2Y1, mineralization was observed only in spinal ligament cells from OPLL patients. These results suggest that P2Y1 expression plays an important role in ectopic bone formation in the spinal ligaments of OPLL patients.
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Affiliation(s)
- Sunao Tanaka
- Department of Pharmacology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori 036-8562, Japan
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Suckale J, Solimena M. The insulin secretory granule as a signaling hub. Trends Endocrinol Metab 2010; 21:599-609. [PMID: 20609596 DOI: 10.1016/j.tem.2010.06.003] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 06/01/2010] [Accepted: 06/03/2010] [Indexed: 02/06/2023]
Abstract
The insulin granule was previously thought of as merely a container, but accumulating evidence suggests that it also acts as a signaling node. Regulatory pathways intersect at but also originate from the insulin granule membrane. Examples include the small G-proteins Rab3a and Rab27a, which influence granule movement, and the transmembrane proteins (tyrosine phosphatase receptors type N) PTPRN and PTPRN2, which upregulate β-cell transcription and proliferation. In addition, many cosecreted compounds possess regulatory functions, often related to energy metabolism. For instance, ATP and γ-amino butyric acid (GABA) modulate insulin and glucagon secretion, respectively; C-peptide protects β-cells and kidney cells; and amylin reduces gastric emptying and food intake via the brain. In this paper, we review the current knowledge of the insulin granule proteome and discuss its regulatory functions.
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Affiliation(s)
- Jakob Suckale
- Molecular Diabetology, Paul Langerhans Institute Dresden, School of Medicine and University Clinic Carl Gustav Carus, Dresden University of Technology, Dresden 01307, Germany
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Lavoie EG, Fausther M, Kauffenstein G, Kukulski F, Künzli BM, Friess H, Sévigny J. Identification of the ectonucleotidases expressed in mouse, rat, and human Langerhans islets: potential role of NTPDase3 in insulin secretion. Am J Physiol Endocrinol Metab 2010; 299:E647-56. [PMID: 20682839 DOI: 10.1152/ajpendo.00126.2010] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Extracellular nucleotides and adenosine regulate endocrine pancreatic functions such as insulin secretion by Langerhans islet β-cells via the activation of specific P2 and P1 receptors. Membrane-bound ectonucleotidases regulate the local concentration of these ligands and consequently control the activation of their receptors. The objective of this study was to identify and localize the major ectonucleotidases, namely NTPDases and ecto-5'-nucleotidase, present in the endocrine pancreas. In addition, the potential implication of ecto-ATPase activity on insulin secretion was investigated in the rat β-cell line INS-1 (832/13). The localization of ectonucleotidase activity and protein was carried out in situ by enzyme histochemistry and immunolocalization in mouse, rat, and human pancreas sections. NTPDase1 was localized in all blood vessels and acini, and NTPDase2 was localized in capillaries of Langerhans islets and in peripheral conjunctive tissue, whereas NTPDase3 was detected in all Langerhans islet cell types. Interestingly, among the mammalian species tested, ecto-5'-nucleotidase was present only in rat Langerhans islet cells, where it was coexpressed with NTPDase3. Notably, the inhibition of NTPDase3 activity by BG0136 and NF279 facilitated insulin release from INS-1 (832/13) cells under conditions of low glycemia, probably by affecting P2 receptor activation. NTPDase3 activity also regulated the inhibitory effect of exogenous ATP in the presence of a high glucose concentration most likely by controlling adenosine production. In conclusion, all pancreatic endocrine cells express NTPDase3 that was shown to modulate insulin secretion in rat INS-1 (832/13) β-cells. Ecto-5'-nucleotidase is expressed in rat Langerhans islet cells but absent in human and mouse endocrine cells.
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Affiliation(s)
- Elise G Lavoie
- Centre de Recherche en Rhumatologie et Immunologie, Centre Hospitalier Universitaire de Québec, Quebec City, Quebec, Canada
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Amisten S, Meidute-Abaraviciene S, Tan C, Olde B, Lundquist I, Salehi A, Erlinge D. ADP mediates inhibition of insulin secretion by activation of P2Y13 receptors in mice. Diabetologia 2010; 53:1927-34. [PMID: 20526761 DOI: 10.1007/s00125-010-1807-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 04/19/2010] [Indexed: 11/29/2022]
Abstract
AIMS/HYPOTHESES To investigate the effects of extracellular purines on insulin secretion from mouse pancreatic islets. METHODS Mouse islets and beta cells were isolated and examined with mRNA real-time quantification, cAMP quantification and insulin and glucagon secretion. ATP release was measured in MIN6c4 cells. Insulin and glucagon secretion were measured in vivo after glucose injection. RESULTS Enzymatic removal of extracellular ATP at low glucose levels increased the secretion of both insulin and glucagon, while at high glucose levels insulin secretion was reduced and glucagon secretion was stimulated, indicating an autocrine effect of purines. In MIN6c4 cells it was shown that glucose does induce release of ATP into the extracellular space. Quantitative real-time PCR demonstrated the expression of the ADP receptors P2Y(1) and P2Y(13) in both intact mouse pancreatic islets and isolated beta cells. The stable ADP analogue 2-MeSADP had no effect on insulin secretion. However, co-incubation with the P2Y(1) antagonist MRS2179 inhibited insulin secretion, while co-incubation with the P2Y(13) antagonist MRS2211 stimulated insulin secretion, indicating that ADP acting via P2Y(1) stimulates insulin secretion, while signalling via P2Y(13) inhibits the secretion of insulin. P2Y(13) antagonism through MRS2211 per se increased the secretion of both insulin and glucagon at intermediate (8.3 mmol/l) and high (20 mmol/l) glucose levels, confirming an autocrine role for ADP. Administration of MRS2211 during glucose injection in vivo resulted in both increased secretion of insulin and reduced glucose levels. CONCLUSIONS/INTERPRETATION In conclusion, ADP acting on the P2Y(13) receptors inhibits insulin release. An antagonist to P2Y(13) increases insulin release and could be evaluated for the treatment of diabetes.
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Affiliation(s)
- S Amisten
- Department of Cardiology, Lund University, Skane University Hospital, Lund, Sweden
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Eliahu S, Barr HM, Camden J, Weisman GA, Fischer B. A novel insulin secretagogue based on a dinucleoside polyphosphate scaffold. J Med Chem 2010; 53:2472-81. [PMID: 20175517 DOI: 10.1021/jm901621h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dinucleoside polyphosphates exert their physiological effects via P2 receptors (P2Rs). They are attractive drug candidates, as they offer better stability and specificity compared to nucleotides, the most common P2 receptor ligands. The activation of pancreatic P2Y receptors by nucleotides increases insulin secretion. Therefore, in the current study, dinucleoside polyphosphate analogues (di-(2-MeS)-adenosine-5',5''-P(1),P(4),alpha,beta-methylene-tetraphosphate), 8, (di-(2-MeS)-adenosine-5',5''-P(1),P(4),beta,gamma-methylene-tetraphosphate), 9, and di-(2-MeS)-adenosine-5',5''-P(1),P(3),alpha,beta-methylene triphosphate, 10, were developed as potential insulin secretagogues. Analogues 8 and 9 were found to be agonists of the P2Y(1)R with EC(50) values of 0.42 and 0.46 microM, respectively, whereas analogue 10 had no activity. Analogues 8-10 were found to be completely resistant to hydrolysis by alkaline phosphatase over 3 h at 37 degrees C. Analogue 8 also was found to be 2.5-fold more stable in human blood serum than ATP, with a half-life of 12.1 h. Analogue 8 administration in rats caused a decrease in a blood glucose load from 155 mg/dL to ca. 100 mg/dL and increased blood insulin levels 4-fold as compared to basal levels. In addition, analogue 8 reduced a blood glucose load to normal values (80-110 mg/dL), unlike the commonly prescribed glibenclamide, which reduced glucose levels below normal values (60 mg/dL). These findings suggest that analogue 8 may prove to be an effective and safe treatment for type 2 diabetes.
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Affiliation(s)
- Shay Eliahu
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
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Oka T, Ohtani M, Suzuki JI. [Identification of novel molecules regulating differentiation and hormone secretion and clarification of their functional mechanisms in pancreatic endocrine cells]. YAKUGAKU ZASSHI 2010; 130:377-88. [PMID: 20190522 DOI: 10.1248/yakushi.130.377] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In order to find novel bioactive molecules regulating differentiation and hormone secretion of pancreatic endocrine cells, the effects of various substances including purinergic receptor agonists and inhibitors of polyamine biosynthesis were examined in pancreatic islets and several pancreatic cell lines. The nicotinic alpha3beta4 receptor was found to be present and capable of increasing cytoplasmic Ca(2+) concentration ([Ca(2+)](i)) and insulin secretion in mouse pancreatic Beta-TC6 cells. Activation of both nicotinic and muscarinic M(3)/M(4) receptors resulted in reduction of insulin release when compared with stimulation of muscarinic receptor alone in Beta-TC6 cells. In mouse islets, purinergic P2Y(1) and P2Y(6) receptors, which are coupled to Gq proteins, were expressed and appeared to regulate insulin secretion through Ca(2+) mobilization from intracellular stores. Similar results were observed in Beta-TC6 cells. Spermidine, one of polyamines, was found to modulate insulin synthesis and [Ca(2+)](i) in Beta-TC6 cells by use of a specific spermidine synthesis inhibitor, trans-4-methylcyclohexylamine (MCHA). Antizyme, which binds to ornithine decarboxylase (ODC) and thereby reduces the cellular polyamine level, was found to be necessary for conversion of ASPC-1 cells, a pancreatic ductal tumor cell line, into alpha-cells forming the islet-like structure and expressing glucagon gene. These findings help advance our understanding of the complex mechanisms involved in the regulation of pancreatic endocrine cell function and develop new therapeutic agents in diabetes mellitus.
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Affiliation(s)
- Takami Oka
- Research Institute of Pharmaceutical Sciences, Musashino University, Japan.
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ATP-gated P2X3 receptors constitute a positive autocrine signal for insulin release in the human pancreatic beta cell. Proc Natl Acad Sci U S A 2010; 107:6465-70. [PMID: 20308565 DOI: 10.1073/pnas.0908935107] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Extracellular ATP has been proposed as a paracrine signal in rodent islets, but it is unclear what role ATP plays in human islets. We now show the presence of an ATP signaling pathway that enhances the human beta cell's sensitivity and responsiveness to glucose fluctuations. By using in situ hybridization, RT-PCR, immunohistochemistry, and Western blotting as well as recordings of cytoplasmic-free Ca(2+) concentration, [Ca(2+)](i), and hormone release in vitro, we show that human beta cells express ionotropic ATP receptors of the P2X(3) type and that activation of these receptors by ATP coreleased with insulin amplifies glucose-induced insulin secretion. Released ATP activates P2X(3) receptors in the beta-cell plasma membrane, resulting in increased [Ca(2+)](i) and enhanced insulin secretion. Therefore, in human islets, released ATP forms a positive autocrine feedback loop that sensitizes the beta cell's secretory machinery. This may explain how the human pancreatic beta cell can respond so effectively to relatively modest changes in glucose concentration under physiological conditions in vivo.
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Petit P, Lajoix AD, Gross R. P2 purinergic signalling in the pancreatic beta-cell: control of insulin secretion and pharmacology. Eur J Pharm Sci 2009; 37:67-75. [PMID: 19429412 DOI: 10.1016/j.ejps.2009.01.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 01/13/2009] [Accepted: 01/19/2009] [Indexed: 10/21/2022]
Abstract
Extracellular adenosine triphosphate is able to modulate pancreatic beta-cell function, acting on P2 purinergic ionotropic (P2X) and metabotropic (P2Y) receptors. Physiologically, ATP entrains beta-cells into a common rhythm by coordinating Ca(2+) oscillations; it plays a central role in insulin secretion pulsatility. ATP also triggers a positive feedback signal amplifying glucose-induced insulin release, which argues for a potential pharmacological application. ATP has consistently been shown to increase cytoplasmic free calcium concentration, notably in human tissue. Acting on P2X receptors, of which different molecular subtypes are expressed in beta-cells, it leads to a transient insulin release that may involve a closure of K(ATP) channels or a rapidly decaying inward current. Activation of G-protein-coupled P2Y receptors triggers different signalling pathways and amplifies insulin release in a glucose-dependent way. It has recently been shown that pancreatic beta-cells express different molecular subtypes of receptors, which may explain the complex interaction of P2Y ligands on high- and low-affinity binding sites. Despite the complexity of this purinergic pharmacology, consistent pre-clinical data suggest the potential of P2Y receptor agonists as drug candidates for type 2 diabetes.
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Affiliation(s)
- Pierre Petit
- Montpellier I University and CNRS UMR 5232, Centre for Pharmacology and Innovation in Diabetes, Montpellier, France.
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Ohtani M, Suzuki JI, Jacobson KA, Oka T. Evidence for the possible involvement of the P2Y(6) receptor in Ca (2+) mobilization and insulin secretion in mouse pancreatic islets. Purinergic Signal 2008; 4:365-75. [PMID: 18784987 PMCID: PMC2583206 DOI: 10.1007/s11302-008-9122-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Accepted: 08/22/2008] [Indexed: 11/30/2022] Open
Abstract
Subtypes of purinergic receptors involved in modulation of cytoplasmic calcium ion concentration ([Ca2+]i) and insulin release in mouse pancreatic β-cells were examined in two systems, pancreatic islets in primary culture and beta-TC6 insulinoma cells. Both systems exhibited some physiological responses such as acetylcholine-stimulated [Ca2+]i rise via cytoplasmic Ca2+ mobilization. Addition of ATP, ADP, and 2-MeSADP (each 100 µM) transiently increased [Ca2+]i in single islets cultured in the presence of 5.5 mM (normal) glucose. The potent P2Y1 receptor agonist 2-MeSADP reduced insulin secretion significantly in islets cultured in the presence of high glucose (16.7 mM), whereas a slight stimulation occurred at 5.5 mM glucose. The selective P2Y6 receptor agonist UDP (200 µM) transiently increased [Ca2+]i and reduced insulin secretion at high glucose, whereas the P2Y2/4 receptor agonist UTP and adenosine receptor agonist NECA were inactive. [Ca2+]i transients induced by 2-MeSADP and UDP were antagonized by suramin (100 µM), U73122 (2 µM, PLC inhibitor), and 2-APB (10 or 30 µM, IP3 receptor antagonist), but neither by staurosporine (1 µM, PKC inhibitor) nor depletion of extracellular Ca2+. The effect of 2-MeSADP on [Ca2+]i was also significantly inhibited by MRS2500, a P2Y1 receptor antagonist. These results suggested that P2Y1 and P2Y6 receptor subtypes are involved in Ca2+ mobilization from intracellular stores and insulin release in mouse islets. In beta-TC6 cells, ATP, ADP, 2-MeSADP, and UDP transiently elevated [Ca2+]i and slightly decreased insulin secretion at normal glucose, while UTP and NECA were inactive. RT-PCR analysis detected mRNAs of P2Y1 and P2Y6, but not P2Y2 and P2Y4 receptors.
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Affiliation(s)
- Masahiro Ohtani
- Research Institute of Pharmaceutical Sciences, Musashino University, 1-1-20 Shinmachi, Nishi-Tokyo, Tokyo, 202-8585, Japan
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Abstract
OBJECTIVES Glucose-induced insulin secretion from pancreatic beta cells is modulated by several hormones and transmitters, namely adenosine triphosphate (ATP) via purinergic receptors. Although P2Y receptors are well documented in beta cells, the presence of P2X receptors remains elusive. We present the first electrophysiological evidence for the presence of P2X receptors in single beta cells of different species. METHODS Ionic currents were recorded from voltage-clamped beta cells near their resting potential using the perforated (nystatin) whole-cell patch-clamp configuration. Receptors were detected by immunocytochemistry. RESULTS When bathed in substimulatory (2 mM) glucose, mouse beta cells, isolated from islets displaying immunochemical colocalization of P2X1 or P2X3 receptors and insulin, developed large (approximately 250 pA/pF), rapidly activating, and then biexponentially decaying (tau1, approximately 20 milliseconds/tau2, approximately 1 second) inward currents on exposure to micromolar concentrations of ATP and alpha,beta-methylene ATP. The ATP also evoked inward currents (100-300 pA/pF) from porcine and human beta cells, albeit with a slower and more complex inactivation pattern. CONCLUSIONS The ATP-gated ion channels are present in pancreatic beta cells from different species. Specifically, mouse beta cells express rapidly desensitizing P2X1 and P2X3 receptors. Paracrine or neural activation of these receptors may contribute to the initial outburst of glucose- or acetylcholine-evoked insulin release, thus enhancing the islet secretory response.
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Parandeh F, Abaraviciene SM, Amisten S, Erlinge D, Salehi A. Uridine diphosphate (UDP) stimulates insulin secretion by activation of P2Y6 receptors. Biochem Biophys Res Commun 2008; 370:499-503. [PMID: 18387359 DOI: 10.1016/j.bbrc.2008.03.119] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Accepted: 03/26/2008] [Indexed: 11/26/2022]
Abstract
We examined the transcriptional expression and functional effects of receptors for the extracellular pyrimidines uridine triphosphate (UTP) and uridine diphosphate (UDP), on insulin and glucagon secretion in isolated mouse pancreatic islets and purified beta-cells. Using real-time PCR, the UDP receptor P2Y(6) was found to be highly expressed in both whole islets and beta-cells purified by repeated counter-flow elutriation, whereas no mRNA expression for UTP receptors P2Y(4) and P2Y(2) could be detected. Functional in vitro experiments revealed that the P2Y(6) agonist UDPbetaS dose-dependently enhanced insulin and glucagon release during short-term incubation (1h), while P2Y(6) activation during a longer period (24h), selectively increased insulin release, especially at high glucose levels. The corresponding EC(50) value for UDPbetaS ranged from 3.2 x 10(-8)M to 1.6 x 10(-8)M for both glucose concentrations. The P2Y(6) antagonist MRS2578 inhibited the effects of UDPbetaS, supporting a P2Y(6) specific effect. In addition to negative RT-PCR results, the lack of response to UTPgammaS a selective P2Y(2/4) agonist further rule out the involvement of P2Y(2/4) receptors in the islet hormone release. Our results suggest a modulatory role for UDP via a functional active P2Y(6) receptor in the regulation of islet hormone release.
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Affiliation(s)
- Fariborz Parandeh
- Department of Clinical Science, CRC, Lund University Hospital, Malmö, S-221 85 Lund, Sweden
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Novak I. Purinergic receptors in the endocrine and exocrine pancreas. Purinergic Signal 2007; 4:237-53. [PMID: 18368520 DOI: 10.1007/s11302-007-9087-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 11/06/2007] [Indexed: 11/28/2022] Open
Abstract
The pancreas is a complex gland performing both endocrine and exocrine functions. In recent years there has been increasing evidence that both endocrine and exocrine cells possess purinergic receptors, which influence processes such as insulin secretion and epithelial ion transport. Most commonly, these processes have been viewed separately. In beta cells, stimulation of P2Y(1) receptors amplifies secretion of insulin in the presence of glucose. Nucleotides released from secretory granules could also contribute to autocrine/paracrine regulation in pancreatic islets. In addition to P2Y(1) receptors, there is also evidence for other P2 and adenosine receptors in beta cells (P2Y(2), P2Y(4), P2Y(6), P2X subtypes and A(1) receptors) and in glucagon-secreting alpha cells (P2X(7), A(2) receptors). In the exocrine pancreas, acini release ATP and ATP-hydrolysing and ATP-generating enzymes. P2 receptors are prominent in pancreatic ducts, and several studies indicate that P2Y(2), P2Y(4), P2Y(11), P2X(4) and P2X(7) receptors could regulate secretion, primarily by affecting Cl(-) and K(+) channels and intracellular Ca(2+) signalling. In order to understand the physiology of the whole organ, it is necessary to consider the full complement of purinergic receptors on different cells as well as the structural and functional relation between various cells within the whole organ. In addition to the possible physiological function of purinergic receptors, this review analyses whether the receptors could be potential therapeutic targets for drug design aimed at treatment of pancreatic diseases.
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Affiliation(s)
- I Novak
- Department of Biosciences, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Ø, Denmark,
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Duarte JMN, Oses JP, Rodrigues RJ, Cunha RA. Modification of purinergic signaling in the hippocampus of streptozotocin-induced diabetic rats. Neuroscience 2007; 149:382-91. [PMID: 17869435 DOI: 10.1016/j.neuroscience.2007.08.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Revised: 07/26/2007] [Accepted: 07/26/2007] [Indexed: 10/23/2022]
Abstract
Diabetic encephalopathy is a recognized complication of untreated diabetes resulting in a progressive cognitive impairment accompanied by modification of hippocampal function. The purinergic system is a promising novel target to control diabetic encephalopathy since it might simultaneously control hippocampal synaptic plasticity and glucose handling. We now tested whether streptozotocin-induced diabetes led to a modification of extracellular ATP homeostasis and density of membrane ATP (P2) receptors in the hippocampus, a brain structure involved in learning and memory. The extracellular levels of ATP, evaluated in the cerebrospinal fluid, were reduced by 60.4+/-17.0% in diabetic rats. Likewise, the evoked release of ATP as well as its extracellular catabolism was also decreased in hippocampal nerve terminals of diabetic rats by 52.8+/-10.9% and 38.7+/-6.5%, respectively. Western blot analysis showed that the density of several P2 receptors (P2X(3,5,7) and P2Y(2,6,11)) was decreased in hippocampal nerve terminals. This indicates that the synaptic ATP signaling is globally depressed in diabetic rats, which may contribute for diabetes-associated decrease of synaptic plasticity. In contrast, the density of P2 receptors (P2X(1,2,5,6,7) and P2Y(6) but not P2Y(2)) increased in whole hippocampal membranes, suggesting an adaptation of non-synaptic P2 receptors to sense decreased levels of extracellular ATP in diabetic rats, which might be aimed at preserving the non-synaptic purinergic signaling.
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Affiliation(s)
- J M N Duarte
- Centre for Neurosciences of Coimbra, Faculty of Medicine, Institute of Biochemistry, University of Coimbra, 3004-504 Coimbra, Portugal.
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Abstract
This review is focused on purinergic neurotransmission, i.e., ATP released from nerves as a transmitter or cotransmitter to act as an extracellular signaling molecule on both pre- and postjunctional membranes at neuroeffector junctions and synapses, as well as acting as a trophic factor during development and regeneration. Emphasis is placed on the physiology and pathophysiology of ATP, but extracellular roles of its breakdown product, adenosine, are also considered because of their intimate interactions. The early history of the involvement of ATP in autonomic and skeletal neuromuscular transmission and in activities in the central nervous system and ganglia is reviewed. Brief background information is given about the identification of receptor subtypes for purines and pyrimidines and about ATP storage, release, and ectoenzymatic breakdown. Evidence that ATP is a cotransmitter in most, if not all, peripheral and central neurons is presented, as well as full accounts of neurotransmission and neuromodulation in autonomic and sensory ganglia and in the brain and spinal cord. There is coverage of neuron-glia interactions and of purinergic neuroeffector transmission to nonmuscular cells. To establish the primitive and widespread nature of purinergic neurotransmission, both the ontogeny and phylogeny of purinergic signaling are considered. Finally, the pathophysiology of purinergic neurotransmission in both peripheral and central nervous systems is reviewed, and speculations are made about future developments.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neurscience Centre, Royal Free and University College Medical School, London, UK.
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Lugo-Garcia L, Filhol R, Lajoix AD, Gross R, Petit P, Vignon J. Expression of purinergic P2Y receptor subtypes by INS-1 insulinoma beta-cells: a molecular and binding characterization. Eur J Pharmacol 2007; 568:54-60. [PMID: 17509560 DOI: 10.1016/j.ejphar.2007.04.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Revised: 03/29/2007] [Accepted: 04/10/2007] [Indexed: 10/23/2022]
Abstract
Purinergic P2Y-receptor agonists amplify glucose-induced insulin secretion from pancreatic beta-cells, thus offering new opportunities for the treatment of type 2 diabetes. However, little is known about which subtypes of purinergic P2Y receptors are expressed in these cells. The INS-1 beta-cell line is used as a model of pancreatic beta-cells, expressing most of their properties. Therefore, we investigated the expression of different molecular subtypes in this cell line by means of real time Polymerase Chain Reaction and Western blot. We also performed a characterization of the binding of a prototypic purinergic P2Y agonist, Adenosine-5'-O-(1-[(35)S]thiotriphosphate) (ATP-alpha-[(35)S]), to cell membrane homogenates. The molecular analysis evidenced the presence of five different purinergic P2Y receptor subtypes (P2Y(1), P2Y(2), P2Y(4), P2Y(6) and P2Y(12)), which were expressed at similar levels. The Western blot analysis allowed detecting corresponding proteins. The binding assay demonstrated a specific ATP-alpha-[(35)S] interaction on high (40%) and low (60%) affinity components. The analysis of ATP-alpha-[(35)S] pharmacological profile on both sites permitted to classify the high affinity binding site as representative of the purinergic P2Y(1) receptor subtype and the low affinity binding site of the P2Y(4) and/or P2Y(6) receptor subtypes. ATP-alpha-S and Adenosine-5'-O-(2-thiodiphosphate) (ADP-beta-S) exhibited opposite selectivity on high and low affinity binding sites. Although purinergic P2Y(1) receptor, or a P2Y(1)-like subtype, has been generally considered as that implicated in the modulation of glucose-induced insulin release, the present data show that the beta-cell expresses a complex profile of purinergic P2Y receptor subtypes, the functional implication of which remains to be fully elucidated.
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Affiliation(s)
- Laura Lugo-Garcia
- Montpellier I University and CNRS UMR 5232, Centre for Pharmacology and Innovation in Diabetes, Montpellier, France
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