Cytoprotection against oxidative stress-induced damage of astrocytes by extracellular ATP via P2Y1 receptors

✍ Scribed by Youichi Shinozaki; Schuichi Koizumi; Seiichi Ishida; Jun-Ichi Sawada; Yasuo Ohno; Kazuhide Inoue

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 543 KB
• Volume: 49
• Category: Article
• ISSN: 0894-1491
• DOI: 10.1002/glia.20118

✦ Synopsis

Abstract

Oxidative stress is the main cause of neuronal damage in traumatic brain injury, hypoxia/reperfusion injury, and neurodegenerative disorders. Although extracellular nucleosides, especially adenosine, are well known to protect against neuronal damage in such pathological conditions, the effects of these nucleosides or nucleotides on glial cell damage remain largely unknown. We report that ATP but not adenosine protects against the cell death of cultured astrocytes induced by hydrogen peroxide (H~2~O~2~). ATP ameliorated the H~2~O~2~‐induced decrease in cell viability of astrocytes in an incubation time‐ and concentration‐dependent fashion. Protection by ATP was inhibited by P2 receptor antagonists and was mimicked by P2Y~1~ receptor agonists but not by adenosine. The expressions of P2Y~1~ mRNAs and functional P2Y~1~ receptors in astrocytes were confirmed. Thus, ATP, acting on P2Y~1~ receptors in astrocytes, showed a protective action against H~2~O~2~. The astrocytic protection by the P2Y~1~ receptor agonist 2‐methylthio‐ADP was inhibited by an intracellular Ca^2+^ chelator and a blocker of phospholipase C, indicating the involvement of intracellular signals mediated by Gq/11‐coupled P2Y~1~ receptors. The ATP‐induced protection was inhibited by cycloheximide, a protein synthesis inhibitor, and it took more than 12 h for the onset of the protective action. In the DNA microarray analysis, ATP induced a dramatic upregulation of various oxidoreductase genes. Taken together, ATP acts on P2Y~1~ receptors coupled to Gq/11, resulting in the upregulation of oxidoreductase genes, leading to the protection of astrocytes against H~2~O~2~. © 2004 Wiley‐Liss, Inc.