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The present study aimed to explore the role of P2Y1 receptor in glial fibrillary acidic protein (GFAP) production and glial cell line-derived neurotrophic factor (GDNF) secretion of astrocytes under ischemic insult and the related signaling pathways.
Using transient right middle cerebral artery occlusion (tMCAO) and oxygen-glucose-serum deprivation for 2 h as the model of ischemic injury in vivo and in vitro, immunofluorescence, quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, enzyme linked immunosorbent assay (ELISA) were used to investigate location of P2Y1 receptor and GDNF, the expression of GFAP and GDNF, and the changes of signaling molecules.
Blockage of P2Y1 receptor with the selective antagonist N6-methyl-2′-deoxyadenosine 3′,5′-bisphosphate diammonium (MRS2179) reduced GFAP production and increased GDNF production in the antagonist group as compared with simple ischemic group both in vivo and in vitro. Oxygen-glucose-serum deprivation and blockage of P2Y1 receptor caused elevation of phosphorylated Akt and cAMP response element binding protein (CREB), and reduction of phosphorylated Janus kinase2 (JAK2) and signal transducer and activator of transcription3 (STAT3, Ser727). After blockage of P2Y1 receptor and deprivation of oxygen-glucose-serum, AG490 (inhibitor of JAK2) reduced phosphorylation of STAT3 (Ser727) as well as expression of GFAP; LY294002, an inhibitor of phosphatidylinositol 3-kinase (PI3-K), decreased phosphorylation of Akt and CREB; the inhibitor of mitogen-activated protein kinase kinase1/2 (MEK1/2) U0126, an important molecule of Ras/extracellular signal-regulated kinase (ERK) signaling pathway, decreased the phosphorylation of JAK2, STAT3 (Ser727), Akt and CREB.
These results suggest that P2Y1 receptor plays a role in the production of GFAP and GDNF in astrocytes under transient ischemic condition and the related signaling pathways may be JAK2/STAT3 and PI3-K/Akt/CREB, respectively, and that crosstalk probably exists between them.
研究P2Y1受体对缺血时星形胶质细胞产生胶质原纤维酸性蛋白(glial fibrillary acidic protein, GFAP)及胶质细胞源性神经营养因子(glial cell line-derived neurotrophic factor, GDNF)的影响及其相关信号通路。
分别利用右侧大脑中动脉线拴阻塞及培养细胞缺氧无营养后恢复正常培养, 造成体内、 外缺血再灌注模型。 用免疫荧光标记、 实时定量RT-PCR、 Western blotting、 酶联免疫吸附试验观察P2Y1受体、 GDNF定位, 检测GFAP、 GDNF及信号分子的表达变化。
与单纯性缺血组比较, 用选择性拮抗剂MRS2179阻断P2Y1受体后, 可使体内、 外星形胶质细胞产生的GFAP减少, 同时使其产生GDNF增加。 体外缺氧无营养并阻断P2Y1受体后: 可使磷酸化蛋白激酶B(Akt)及cAMP反应元件结合蛋白(cAMP response element binding protein, CREB)升高, 而使磷酸化JAK2及STAT3(Ser727)降低; JAK2的抑制剂AG490在降低磷酸化STAT3(Ser727)的同时也降低GFAP表达水平; PI3-K的抑制剂LY294002可降低磷酸化的Akt及CREB; MEK1/2抑制剂U0126可同时降低磷酸化的JAK2、STAT3 (Ser727)、 Akt及CREB。
P2Y1受体参与短时性缺血时星形胶质细胞GFAP及GDNF的产生过程, 相关信号途径分别为JAK2/STAT3和PI3-K/AKT/CREB, 并且两条途径存在串话。