Objective: To investigate whether JNK-caspase-dependent apoptotic pathway is involved in Abeta(31-35)-induced apoptosis of cultured cortical neurons.
Methods: Cultured cortical neurons were treated with Abeta(31-35) (25 micromol/L) for 4 h, 8 h, 16 h and 24 h, respectively. Caspase activities were measured using a spectrophotometer. Levels of c-Jun phosphorylation (p-c-Jun) and Fas ligand (FasL) expression were assessed by immunocytochemistry method and quantified using Image-pro plus11.0 image processing and analysis software.
Results: Treatment with Abeta(31-35) (25 micromol/L) for 24 h induced significant increases in the activities of caspase-3 and caspase-8 in the cortical neurons. Besides, Abeta(31-35) could time-dependently enhance the expression of p-c-Jun protein. Moreover, SP600125 application (100 nmol/L) could completely abolish Abeta(31-35) neurotoxicity. The increase in FasL expression was detected at 8 h, 16 h and 24 h after Abeta(31-35) treatment, and SP600125 (100 nmol/L) significantly inhibited FasL expression.
Conclusion: JNK-c-Jun-FasL-caspase-dependent extrinsic apoptotic pathway plays a critical role in mediating Abeta(31-35)-induced apoptosis of cultured neurons.
目的: 探讨JNK信号通路在Aβ31–35诱导的神经元凋亡过程中的作用。
方法: 经老化处理的Aβ31–35 (终浓度为25 µmol/L)制备AD 细胞模型, 采用生物比色法检测caspase-3和caspase-8 的活性。 采用免疫细胞化学技术观察不同时间点磷酸化c-Jun (p-c-Jun)及Fas ligand (FasL) 蛋白的表达情况, 并用IPP11.0图像分析软件进行定量分析。
结果: Aβ31–35 孵育24 h能显著提高神经元内caspase-3和caspase-8的活性。 Aβ31–35孵育4 h时p-c-Jun蛋白表达水平开始升高, 在8h升高最显著, 呈现一定的时间依赖性; JNK特异性抑制剂SP600125能抑制Aβ31–35对p-c-Jun蛋白表达的诱导作用。 Aβ31–35孵育8 h时出现FasL蛋白表达的升高, 而SP600125则能抑制这一作用。
结论: JNK激活的外源性凋亡途径在Aβ31–35诱导的神经元凋亡过程中发挥一定的作用。