IL-1β通过PI3K/Akt/mTOR途径促进神经元活化

IL-1β stimulated neuron activation via PI3K/Akt/mTOR pathway

目的:观察白细胞介素-1β(IL-1β)刺激对神经元活化的影响。方法:利用IL-1β刺激体外培养的原代神经元,运用慢病毒转染shRNA使PI3K的p85亚基(PI3K-p85)沉默、哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,m TOR)抑制剂雷帕霉素预处理阻断m TOR、酪氨酸激酶家族抑制剂PP2抑制p85向IL-1受体I型(IL-1RI)募集等方式预处理神经元,检测PI3K-p85、与IL-1RI结合的PI3K-p85、p-Akt、p-p70S6K以及微管相关蛋白2(MAP2)在神经元内的变化及相互作用;利用FM4-64染色观察各组神经元突触胞吞情况。结果:利用IL-1β刺激体外培养的海马神经元可增加细胞内PI3K-p85、p-Akt、p-p70S6K、MAP2以及与IL-1RI结合的PI3K-p85的水平(P<0.05),并且神经元突触的胞吞作用明显加剧(P<0.05);抑制PI3K-p85可以下调IL-1β所致的p-Akt、pp70S6k和MAP2水平增加(P<0.05),神经元突触的胞吞作用减弱(P<0.05);抑制m TOR也能下调IL-1β所致的PI3K-p85、p-Akt、p-p70S6K和MAP2水平增加(P<0.05),神经元突触的胞吞作用减弱(P<0.05);抑制p85亚基与IL-1RI的结合也可以下调IL-1β所致的p-Akt、p-p70S6K和MAP2水平增加(P<0.05)。结论:促炎因子IL-1β通过IL-1RI与PI3K-p85结合使PI3K-p85活化,进而磷酸化Akt和m TOR下游物质p70S6K,促进神经元突触增生及活化,这可能是内侧颞叶癫痫向慢性化进展的机制之一。

AIM：To study the effect of interleukin-1β（ IL-1β） on neuron activation during the process of me-dial temporal lobe epilepsy （ MTLE ） .METHODS： IL-1β, rapamycin [ an inhibitor of mammalian target of rapamycin （mTOR）]and lentiviral transfection to knockdown PI3K-p85 were used to pre-treat the neurons.The protein levels of PI3K-p85, p-Akt, p-p70S6K and MAP2 were detected and the relationship among the tested cytokines was analyzed.The neuron endocytosis was observed in each group.RESULTS：IL-1βincreased the protein levels of PI3K-p85, p-Akt and p-p70S6K, up-regulated the expression of PI3K-p85 binding with IL-1RI in the neurons, and increased the neuron endocyto-sis compared with control group （P〈0.05） .Tese processes were inhibited by rapamycin and silence of PI3K-p85 （P〈0.05）.Inhibition of the PI3K-p85 binding to IL-1RI decreased the protein levels of p-Akt, p-p70S6K and MAP2 which were increased by IL-1βstimulation （P〈0.05）.CONCLUSION： IL-1βactivates PI3K-p85 by binding with IL-1RI to promote the activation and proliferation of neuron synapses via PI3K/Akt/mTOR signaling pathway, which might be one of the mechanisms in MTLE chronic progress.