1
|
Bartley C, Brun T, Oberhauser L, Grimaldi M, Molica F, Kwak BR, Bosco D, Chanson M, Maechler P. Chronic fructose renders pancreatic β-cells hyper-responsive to glucose-stimulated insulin secretion through extracellular ATP signaling. Am J Physiol Endocrinol Metab 2019; 317:E25-E41. [PMID: 30912960 DOI: 10.1152/ajpendo.00456.2018] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Fructose is widely used as a sweetener in processed food and is also associated with metabolic disorders, such as obesity. However, the underlying cellular mechanisms remain unclear, in particular, regarding the pancreatic β-cell. Here, we investigated the effects of chronic exposure to fructose on the function of insulinoma cells and isolated mouse and human pancreatic islets. Although fructose per se did not acutely stimulate insulin exocytosis, our data show that chronic fructose rendered rodent and human β-cells hyper-responsive to intermediate physiological glucose concentrations. Fructose exposure reduced intracellular ATP levels without affecting mitochondrial function, induced AMP-activated protein kinase activation, and favored ATP release from the β-cells upon acute glucose stimulation. The resulting increase in extracellular ATP, mediated by pannexin1 (Panx1) channels, activated the calcium-mobilizer P2Y purinergic receptors. Immunodetection revealed the presence of both Panx1 channels and P2Y1 receptors in β-cells. Addition of an ectonucleotidase inhibitor or P2Y1 agonists to naïve β-cells potentiated insulin secretion stimulated by intermediate glucose, mimicking the fructose treatment. Conversely, the P2Y1 antagonist and Panx1 inhibitor reversed the effects of fructose, as confirmed using Panx1-null islets and by the clearance of extracellular ATP by apyrase. These results reveal an important function of ATP signaling in pancreatic β-cells mediating fructose-induced hyper-responsiveness.
Collapse
Affiliation(s)
- Clarissa Bartley
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center , Geneva , Switzerland
- Faculty Diabetes Center, University of Geneva Medical Center , Geneva , Switzerland
| | - Thierry Brun
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center , Geneva , Switzerland
- Faculty Diabetes Center, University of Geneva Medical Center , Geneva , Switzerland
| | - Lucie Oberhauser
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center , Geneva , Switzerland
- Faculty Diabetes Center, University of Geneva Medical Center , Geneva , Switzerland
| | - Mariagrazia Grimaldi
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center , Geneva , Switzerland
- Faculty Diabetes Center, University of Geneva Medical Center , Geneva , Switzerland
| | - Filippo Molica
- Department of Pathology and Immunology, University of Geneva Medical Center , Geneva , Switzerland
| | - Brenda R Kwak
- Department of Pathology and Immunology, University of Geneva Medical Center , Geneva , Switzerland
- Division of Cardiology, University of Geneva Medical Center , Geneva , Switzerland
| | - Domenico Bosco
- Faculty Diabetes Center, University of Geneva Medical Center , Geneva , Switzerland
- Department of Surgery, Cell Isolation and Transplantation Center, Geneva University Hospital , Geneva , Switzerland
| | - Marc Chanson
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center , Geneva , Switzerland
- Department of Pediatrics, Geneva University Hospital , Geneva , Switzerland
| | - Pierre Maechler
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center , Geneva , Switzerland
- Faculty Diabetes Center, University of Geneva Medical Center , Geneva , Switzerland
| |
Collapse
|
2
|
Tchernookova BK, Heer C, Young M, Swygart D, Kaufman R, Gongwer M, Shepherd L, Caringal H, Jacoby J, Kreitzer MA, Malchow RP. Activation of retinal glial (Müller) cells by extracellular ATP induces pronounced increases in extracellular H+ flux. PLoS One 2018; 13:e0190893. [PMID: 29466379 PMCID: PMC5821311 DOI: 10.1371/journal.pone.0190893] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/21/2017] [Indexed: 11/25/2022] Open
Abstract
Small alterations in extracellular acidity are potentially important modulators of neuronal signaling within the vertebrate retina. Here we report a novel extracellular acidification mechanism mediated by glial cells in the retina. Using self-referencing H+-selective microelectrodes to measure extracellular H+ fluxes, we show that activation of retinal Müller (glial) cells of the tiger salamander by micromolar concentrations of extracellular ATP induces a pronounced extracellular H+ flux independent of bicarbonate transport. ADP, UTP and the non-hydrolyzable analog ATPγs at micromolar concentrations were also potent stimulators of extracellular H+ fluxes, but adenosine was not. The extracellular H+ fluxes induced by ATP were mimicked by the P2Y1 agonist MRS 2365 and were significantly reduced by the P2 receptor blockers suramin and PPADS, suggesting activation of P2Y receptors. Bath-applied ATP induced an intracellular rise in calcium in Müller cells; both the calcium rise and the extracellular H+ fluxes were significantly attenuated when calcium re-loading into the endoplasmic reticulum was inhibited by thapsigargin and when the PLC-IP3 signaling pathway was disrupted with 2-APB and U73122. The anion transport inhibitor DIDS also markedly reduced the ATP-induced increase in H+ flux while SITS had no effect. ATP-induced H+ fluxes were also observed from Müller cells isolated from human, rat, monkey, skate and lamprey retinae, suggesting a highly evolutionarily conserved mechanism of potential general importance. Extracellular ATP also induced significant increases in extracellular H+ flux at the level of both the outer and inner plexiform layers in retinal slices of tiger salamander which was significantly reduced by suramin and PPADS. We suggest that the novel H+ flux mediated by ATP-activation of Müller cells and of other glia as well may be a key mechanism modulating neuronal signaling in the vertebrate retina and throughout the brain.
Collapse
Affiliation(s)
- Boriana K. Tchernookova
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail: (BKT); (RPM)
| | - Chad Heer
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States of America
| | - Marin Young
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States of America
| | - David Swygart
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States of America
| | - Ryan Kaufman
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States of America
| | - Michael Gongwer
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States of America
| | - Lexi Shepherd
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States of America
| | - Hannah Caringal
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States of America
| | - Jason Jacoby
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Matthew A. Kreitzer
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States of America
| | - Robert Paul Malchow
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Ophthalmology & Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail: (BKT); (RPM)
| |
Collapse
|
3
|
Pacheco PAF, Ferreira LGB, Alves LA, Faria RX. Modulation of P2 receptors on pancreatic β-cells by agonists and antagonists: a molecular target for type 2 diabetes treatment. Curr Diabetes Rev 2013; 9:228-36. [PMID: 23506378 DOI: 10.2174/1573399811309030004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 12/19/2012] [Accepted: 12/20/2012] [Indexed: 11/22/2022]
Abstract
Morbidity and mortality from diabetes mellitus (DM) are serious worldwide concerns. By the year 2030, the estimated number of diabetic patients will reach a staggering 439 million worldwide. Diabetes mellitus type 2 (DM2), which involves disturbances in both insulin secretion and resistance, is the most common form of diabetes and affects approximately 5 to 7% of the world's population. When a patient with DM2 cannot regulate his or her blood glucose levels through diet, weight loss, or exercise, oral medications, such as hypoglycemic agents (i.e., sulphonylureas, biguanides, alpha glucosidase inhibitors and thiazolidinediones), are crucial. Here, we discuss some physiological aspects of P2 receptors on pancreatic β-cells, which express a variety of P2 receptor isoforms. These receptors enhance glucose-dependent insulin release. In addition, we speculate on the potential of purinergic compounds as novel or additional treatments for Type 2 Diabetes mellitus.
Collapse
MESH Headings
- Animals
- Cell Line
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/metabolism
- Humans
- Hypoglycemic Agents/pharmacology
- Immunohistochemistry
- Insulin-Secreting Cells/drug effects
- Insulin-Secreting Cells/metabolism
- Mice
- Phosphorylation
- Purinergic P2 Receptor Agonists/pharmacology
- Purinergic P2Y Receptor Antagonists/pharmacology
- Rats
- Receptors, Purinergic P2/drug effects
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2X/drug effects
- Receptors, Purinergic P2X/metabolism
- Receptors, Purinergic P2Y/drug effects
- Receptors, Purinergic P2Y/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
Collapse
|
4
|
Erdorf M, von der Ohe J, Seifert R. Impaired P2X and P2Y receptor-mediated signaling in HPRT-deficient B103 neuroblastoma cells. Neurosci Lett 2011; 504:311-5. [PMID: 21982803 DOI: 10.1016/j.neulet.2011.09.054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 09/22/2011] [Accepted: 09/23/2011] [Indexed: 11/17/2022]
Abstract
Defect of hypoxanthine phosphoribosyl transferase (HPRT) causes Lesch-Nyhan disease (LND), but the link between HPRT deficiency and the self-injurious behavior of LND is unknown. In a previous study (Pinto et al., J. Neurochem. 72 (2005) 1579-1586) we reported on a decrease in nucleotidase activity in membranes of several HPRT(-) cell lines and fibroblasts from LND patients. Since nucleotidases are involved in ATP-induced signal transduction, in the present study, we tested the hypothesis that P2X and P2Y receptor-mediated signal transduction is impaired in HPRT deficiency. As model we studied rat B103 neuroblastoma cells. Compared to control cells, in HPRT(-) cells, NTP and NDP-induced Ca(2+) influx across the membrane and Ca(2+) mobilization from intracellular stores were impaired. Both P2X and P2Y receptors were involved in the responses. Quantitative real-time PCR revealed reduced expression of receptors P2X(3), P2X(5), P2Y(2), P2Y(4), P2Y(12), P2Y(13) and P2Y(14) in HPRT deficiency. Collectively, HPRT deficiency is associated with abnormal purinergic signaling, encompassing P2X and P2Y receptors and nucleotidases.
Collapse
Affiliation(s)
- Miriam Erdorf
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Regensburg, Germany
| | | | | |
Collapse
|
5
|
Trevethick MA. Is uridine a treatment for asthma? Clin Exp Allergy 2011; 40:1436-8. [PMID: 20937059 DOI: 10.1111/j.1365-2222.2010.03600.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|