The P2X7 receptor supports both life and death in fibrogenic pancreatic stellate cells

PLoS One. 2012;7(12):e51164. doi: 10.1371/journal.pone.0051164. Epub 2012 Dec 17.

Abstract

The pancreatic stellate cells (PSCs) have complex roles in pancreas, including tissue repair and fibrosis. PSCs surround ATP releasing exocrine cells, but little is known about purinergic receptors and their function in PSCs. Our aim was to resolve whether PSCs express the multifunctional P2X7 receptor and elucidate how it regulates PSC viability. The number of PSCs isolated from wild type (WT) mice was 50% higher than those from the Pfizer P2X7 receptor knock out (KO) mice. The P2X7 receptor protein and mRNA of all known isoforms were expressed in WT PSCs, while KO PSCs only expressed truncated versions of the receptor. In culture, the proliferation rate of the KO PSCs was significantly lower. Inclusion of apyrase reduced the proliferation rate in both WT and KO PSCs, indicating importance of endogenous ATP. Exogenous ATP had a two-sided effect. Proliferation of both WT and KO cells was stimulated with ATP in a concentration-dependent manner with a maximum effect at 100 µM. At high ATP concentration (5 mM), WT PSCs, but not the KO PSCs died. The intracellular Ca(2+) signals and proliferation rate induced by micromolar ATP concentrations were inhibited by the allosteric P2X7 receptor inhibitor az10606120. The P2X7 receptor-pore inhibitor A438079 partially prevented cell death induced by millimolar ATP concentrations. This study shows that ATP and P2X7 receptors are important regulators of PSC proliferation and death, and therefore might be potential targets for treatments of pancreatic fibrosis and cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / pharmacology
  • Animals
  • Cell Count
  • Cell Death / drug effects
  • Cell Proliferation / drug effects
  • Cell Survival / drug effects
  • Fibrosis
  • Gene Expression Regulation / drug effects
  • Gene Knockout Techniques
  • Mice
  • Mice, Inbred C57BL
  • Pancreatic Stellate Cells / cytology*
  • Pancreatic Stellate Cells / drug effects
  • Pancreatic Stellate Cells / metabolism
  • Pancreatic Stellate Cells / pathology*
  • Receptors, Purinergic P2X7 / deficiency
  • Receptors, Purinergic P2X7 / genetics
  • Receptors, Purinergic P2X7 / metabolism*

Substances

  • Receptors, Purinergic P2X7
  • Adenosine Triphosphate

Grants and funding

This work was supported by the Danish Council for Independent Research | Natural Sciences, the Lundbeck Foundation, the Novo Nordisk Foundation, the Carlsberg Foundation and FP7 Marie Curie Initial Training Network "IonTraC". The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.