Extracellular nucleotides, including ATP, have been demonstrated to transmit important physiological signals in the brain through either G-protein-coupled P2Y receptors or P2X receptors, which are ligand-gated ion channels. In this study, we performed a detailed analysis of the expression of the Gi/
Akt activation is involved in P2Y12 receptor-mediated chemotaxis of microglia
✍ Scribed by Yasuhiro Irino; Yasuko Nakamura; Kazuhide Inoue; Shinichi Kohsaka; Keiko Ohsawa
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 549 KB
- Volume
- 86
- Category
- Article
- ISSN
- 0360-4012
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Microglia play a variety of significant roles in the central nervous system (CNS), and in one of those roles they undergo morphological change in response to neural injury and migrate to the injured region. We previously reported that ATP/ADP promotes microglial chemotaxis via the Gi/o‐coupled P2Y12 receptor; however, the intracellular signaling underlying P2Y12‐receptor‐mediated microglial chemotaxis is not fully understood. In this study, we examined the role of phospholipase C (PLC) and calcium signaling in ADP‐induced microglial chemotaxis. A PLC inhibitor, U73122, significantly suppressed the chemotaxis and completely blocked the ADP‐evoked intracellular calcium response, and a calcium chelator, BAPTA‐AM, inhibited the chemotaxis. These results indicate that ADP‐induced microglial chemotaxis is regulated by a PLC‐mediated calcium pathway. ADP stimulation induced Akt phosphorylation in microglia, and the phosphorylation was inhibited by a P2Y12 receptor antagonist, AR‐C69931MX. The Akt phosphorylation was blocked by U73122 and BAPTA‐AM as well as by a phosphatidylinositol 3‐kinase (PI3K) inhibitor, wortmannin, and inhibition of the Akt activation resulted in failure of chemotaxis. These results indicate that Akt activation is dependent on the PI3K pathway and a PLC‐mediated increase in intracellular calcium and suggest that Akt activation is involved in ADP‐induced microglial chemotaxis. © 2008 Wiley‐Liss, Inc.
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