Involvement of P2X Receptors in the Regulation of Insulin Secretion, Proliferation and Survival in Mouse Pancreatic β-Cells
Copyright policy )Involvement of P2X Receptors in the Regulation of Insulin Secretion, Proliferation and Survival in Mouse Pancreatic β-Cells
In order to clarify the functional role of ionotropic purinergic (P2X) receptors in pancreatic β-cells, we examined the effect of several P2 receptor agonists and antagonists on insulin secretion by mouse pancreatic islets, mouse Beta-TC6 cell proliferation and survival of dispersed islet cells in culture. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed the expression of mRNAs of P2X(4) receptor in mouse islets and P2X(1), P2X(2), P2X(3), P2X(4), P2X(5) and P2X(7) receptors in Beta-TC6 cells. The presence of P2X(4) receptor proteins in islets and Beta-TC6 cells was confirmed by immunofluorescent staining and Western blot analysis. We have previously found that the functional P2Y(1) receptor but not P2Y(2) and P2Y(4) receptors was present in islets. In this study we found that a nonspecific P2 receptor agonist, ATP (1 μM) stimulated insulin secretion by islets in the presence of high glucose (20 mM) in culture. The effect of ATP was partially inhibited by a P2 receptor antagonist PPADS as well as a P2Y(1) receptor antagonist MRS2179. In addition, a P2X(4) receptor potentiator ivermectin per se augmented glucose-induced insulin secretion and slightly potentiated the effect of ATP. These results suggested the involvement of P2Y(1)and P2X receptors. We also found that ATP inhibited proliferation of Beta-TC6 cells in a concentration-dependent manner during 72 h culture. The inhibitory effect of ATP was completely reversed by PPADS and partially by treating cells with small interfering RNA targeted for P2X(4) receptor mRNA. Furthermore, we found that the phosphorylation of the extracellular signal-regulated kinase 1 and 2 (ERK1/2) was suppressed by treatment with ATP in Beta-TC6 cells. In addition, we found that ATP reduced the cell viability and DNA synthesis of islet cells in culture. The effect of ATP on the cell viability was blocked by PPADS or MRS2179. These results suggested that P2X receptors as well as the P2Y(1) receptor played a role in the modulation of insulin secretion, proliferation and cell viability in mouse pancreatic β-cells.
- Osaka Dental University Japan
- Musashino University Japan
- Central Research Institute India
Male, Mitogen-Activated Protein Kinase 1, Purinergic P2 Receptor Agonists, Mitogen-Activated Protein Kinase 3, Cell Survival, Cell Line, Adenosine Diphosphate, Mice, Inbred C57BL, Mice, Adenosine Triphosphate, Glucose, Insulin-Secreting Cells, Pyridoxal Phosphate, Insulin Secretion, Purinergic P2Y Receptor Antagonists, Animals, Insulin, RNA Interference, Phosphorylation, Cell Proliferation
Male, Mitogen-Activated Protein Kinase 1, Purinergic P2 Receptor Agonists, Mitogen-Activated Protein Kinase 3, Cell Survival, Cell Line, Adenosine Diphosphate, Mice, Inbred C57BL, Mice, Adenosine Triphosphate, Glucose, Insulin-Secreting Cells, Pyridoxal Phosphate, Insulin Secretion, Purinergic P2Y Receptor Antagonists, Animals, Insulin, RNA Interference, Phosphorylation, Cell Proliferation
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