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Vol. 28, No. 2, 2011
Issue release date: 2011
Section title: Original Paper
Cell Physiol Biochem 2011;28:355–366
(DOI:10.1159/000331752)

Involvement of P2X Receptors in the Regulation of Insulin Secretion, Proliferation and Survival in Mouse Pancreatic β-Cells

Ohtani M.1,3 · Ohura K.1 · Oka T.2,3
1Department of Pharmacology, Osaka Dental University, Hirakata,2Central Research Institute, Wakunaga Pharmaceutical Co., Ltd, Akitakata,3Research Institute of Pharmaceutical Sciences, Musashino University, Nishi-Tokyo
email Corresponding Author

Abstract

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 P2X4 receptor in mouse islets and P2X1, P2X2, P2X3, P2X4, P2X5 and P2X7 receptors in Beta-TC6 cells. The presence of P2X4 receptor proteins in islets and Beta-TC6 cells was confirmed by immunofluorescent staining and Western blot analysis. We have previously found that the functional P2Y1 receptor but not P2Y2 and P2Y4 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 P2Y1 receptor antagonist MRS2179. In addition, a P2X4 receptor potentiator ivermectin per se augmented glucose-induced insulin secretion and slightly potentiated the effect of ATP. These results suggested the involvement of P2Y1and 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 P2X4 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 P2Y1 receptor played a role in the modulation of insulin secretion, proliferation and cell viability in mouse pancreatic β-cells.

© 2011 S. Karger AG, Basel


  

Key Words

  • ATP
  • P2X receptor
  • Insulin secretion
  • Pancreatic β-cells
  • Proliferation

  

Author Contacts

Takami Oka Ph.D.
Central Research Institute, Wakunaga Pharmaceutical Co., Ltd
1624 Shimokotachi, Koda-cho, Akitakata, Hiroshima 739-1195 (Japan)
Tel./Fax +81-42-468-9199, E-mail oka_tm@wakunaga.co.jp

  

Article Information

Accepted: June 30, 2011
Published online: August 16, 2011
Number of Print Pages : 12

  

Publication Details

Cellular Physiology and Biochemistry (International Journal of Experimental Cellular Physiology, Biochemistry andPharmacology)

Vol. 28, No. 2, Year 2011 (Cover Date: 2011)

Journal Editor: F. Lang, Tübingen
ISSN: 1015–8987 (Print), eISSN: 1421–9778 (Online)

For additional information: http://www.karger.com/journals/cpb


Copyright / Drug Dosage / Disclaimer

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

Abstract

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 P2X4 receptor in mouse islets and P2X1, P2X2, P2X3, P2X4, P2X5 and P2X7 receptors in Beta-TC6 cells. The presence of P2X4 receptor proteins in islets and Beta-TC6 cells was confirmed by immunofluorescent staining and Western blot analysis. We have previously found that the functional P2Y1 receptor but not P2Y2 and P2Y4 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 P2Y1 receptor antagonist MRS2179. In addition, a P2X4 receptor potentiator ivermectin per se augmented glucose-induced insulin secretion and slightly potentiated the effect of ATP. These results suggested the involvement of P2Y1and 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 P2X4 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 P2Y1 receptor played a role in the modulation of insulin secretion, proliferation and cell viability in mouse pancreatic β-cells.

© 2011 S. Karger AG, Basel


  

Author Contacts

Takami Oka Ph.D.
Central Research Institute, Wakunaga Pharmaceutical Co., Ltd
1624 Shimokotachi, Koda-cho, Akitakata, Hiroshima 739-1195 (Japan)
Tel./Fax +81-42-468-9199, E-mail oka_tm@wakunaga.co.jp

  

Article Information

Accepted: June 30, 2011
Published online: August 16, 2011
Number of Print Pages : 12

  

Publication Details

Cellular Physiology and Biochemistry (International Journal of Experimental Cellular Physiology, Biochemistry andPharmacology)

Vol. 28, No. 2, Year 2011 (Cover Date: 2011)

Journal Editor: F. Lang, Tübingen
ISSN: 1015–8987 (Print), eISSN: 1421–9778 (Online)

For additional information: http://www.karger.com/journals/cpb


Article / Publication Details

First-Page Preview
Abstract of Original Paper

Accepted: 6/30/2011
Published online: 8/16/2011
Issue release date: 2011

Number of Print Pages: 0
Number of Figures: 0
Number of Tables: 0

ISSN: 1015-8987 (Print)
eISSN: 1421-9778 (Online)

For additional information: http://www.karger.com/CPB


Copyright / Drug Dosage

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.