激活原代星形胶质细胞α7尼古丁胆碱能受体对PI3K/Akt/HSP70信号通路的影响

Effect of α7nAChRs activation on P13K/Akt/HSP70 signaling pathway in primary astrocyteson

目的研究尼古丁激活星形胶质细胞α7尼古丁胆碱能受体(nAChR)对热休克蛋白(HSP)70表达的影响,探讨激活α7nAChR对阿尔茨海默病(AD)的神经保护作用及其机制。方法从刚出24 h内的小鼠的大脑皮质中分离出原代星形胶质细胞,培养并进行细胞纯度鉴定。将培养好的星形胶质细胞分为空白对照组、尼古丁组、α7nAChR阻断剂MLA组、MLA+尼古丁组、PI3K/Akt信号通路阻断剂LY294002组和LY294002+尼古丁组。用Western印迹法检测细胞内HSP70及P-Akt蛋白的表达情况。结果与对照组相比,尼古丁组中HSP70的表达水平显著升高(P<0.01);与尼古丁组相比,MLA+尼古丁组中HSP70蛋白表达水平受到明显抑制(P<0.05);LY294002+尼古丁组中HSP70蛋白表达水平明显受到抑制(P<0.05);且尼古丁可以显著上调P-Akt蛋白水平(P<0.05),该上调效应能被MLA或LY294002抑制(P<0.05)。结论尼古丁激活星形胶质细胞α7nAChRs,可通过PI3K/Akt信号通路上调HSP70蛋白表达水平。

Objective To investigate the effects of nicotine on the expression of heat shock protein(HSP) 70 via activating the primary astrocyte α7 cholinergic receptor, and explore the neuroprotective mechanism of α7 nAChR and its role of the pathogenesis in Alizheimer disease(AD).Methods Primary astrocytes were isolated from the cerebral cortex of newborn rats within 24 hours and identified. Cells were divided into control, nicotine, α7 nAChR blocker(MLA), MLA+nicotine group, PI3 K/Akt signaling pathway blocker LY294002 and LY294002+nicotine groups. The expression of HSP70 in cells was detected by Western blot.Results Compared with control group, nicotine significantly increased the P-Akt protein level in astrocytes(P<0.05), and the up-regulated efficiency was inhibited by MLA or LY294002(P<0.05). Meanwhile, the expression of HSP70 was significantly increased in the nicotine group(P<0.01). Compared with nicotine group, the expression of HSP70 was inhibited in the nicotine+MLA group(P<0.05) and the expression of HSP70 was inhibited in nicotine+LY294002 group(P<0.01).Conclusions Nicotine activating α7 nAChR in astrocytes can up-regulate HSP70 expression through PI3 K/Akt signaling pathway.