Involvement of P2X4 and P2Y12 receptors in ATP-induced microglial chemotaxis
Involvement of P2X4 and P2Y12 receptors in ATP-induced microglial chemotaxis
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DOI：
10.1002/glia.20489
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发表时间：
2007-04-15
期刊：
影响因子：
6.2
通讯作者：
Inoue, Kazuhide
中科院分区：
文献类型：
--
作者：
Ohsawa, Keiko;Irino, Yasuhiro;Inoue, Kazuhide
我们之前报道过细胞外 ATP 诱导小胶质细胞的膜褶皱和趋化性，并表明它们的诱导是由 Gi/o 蛋白偶联 P2Y(12) 受体 (P2Y(12)R) 介导的。在这里，我们报告发现 P2X(4) 受体 (P2X(4)R) 也参与 ATP 诱导的小胶质细胞趋化性。为了了解小胶质细胞趋化性背后的 P2Y(12)R 下游的细胞内信号通路，我们在 Dunn 趋化室中检查了两种磷脂酰肌醇 3'-激酶 (PI3K) 抑制剂渥曼青霉素和 LY294002 对趋化性的影响。 PI3K 抑制剂显着抑制趋化性，而不影响 ATP 诱导的膜波动。 ATP 刺激会增加小胶质细胞中的 Akt 磷酸化，而 PI3K 抑制剂和 P2Y(12)R 拮抗剂可减少这种增加。这些结果表明 P2Y(12)R 介导的 PI3K 途径激活是小胶质细胞响应 ATP 的趋化性所必需的。我们还发现，当细胞外钙被螯合时，Akt 磷酸化会降低，这表明离子型 P2X 受体通过影响 PI3K 通路参与小胶质细胞趋化性。因此，我们测试了各种P2X(4)R拮抗剂对趋化性的影响，结果表明P2X(4)R的药理学阻断显着抑制了趋化性。通过慢病毒载体系统进行RNA干扰，敲低小胶质细胞中的P2X(4)受体也抑制了小胶质细胞的趋化性。这些结果表明P2X(4)R 和P2Y(12)R 参与ATP 诱导的小胶质细胞趋化性。 (c) 2007 年 Wiley-Liss, Inc.
We previously reported that extracellular ATP induces membrane ruffling and chernotaxis of microglia and suggested that their induction is mediated by the Gi/o-protein coupled P2Y(12) receptor (P2Y(12)R). Here we report discovering that the P2X(4) receptor (P2X(4)R) is also involved in ATP-induced microglial chemotaxis. To understand the intracellular signaling pathway downstream of P2Y(12)R that underlies microglial chemotaxis, we examined the effect of two phosphatidylinositol 3'-kinase (PI3K) inhibitors, wortmannin, and LY294002, on chemotaxis in a Dunn chemotaxis chamber. The PI3K inhibitors significantly suppressed chemotaxis without affecting ATP-induced membrane ruffling. ATP stimulation increased Akt phosphorylation in the microglia, and the increase was reduced by the PI3K inhibitors and a P2Y(12)R antagonist. These results indicate that P2Y(12)R-mediated activation of the PI3K pathway is required for microglial chemotaxis in response to ATP. We also found that the Akt phosphorylation was reduced when extracellular calcium was chelated, suggesting that ionotropic P2X receptors are involved in microglial chemotaxis by affecting the PI3K pathway. We therefore tested the effect of various P2X(4)R antagonists on the chemotaxis, and the results showed that pharmacological blockade of P2X(4)R significantly inhibited it. Knockdown of the P2X(4) receptor in microglia by RNA interference through the lentivirus vector system also suppressed the microglial chemotaxis. These results indicate that P2X(4)R as well as P2Y(12)R is involved in ATP-induced microglial chemotaxis. (c) 2007 Wiley-Liss, Inc.