Protein aggregation after transient cerebral ischemia
Protein aggregation after transient cerebral ischemia
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DOI：
10.1523/jneurosci.20-09-03191.2000
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发表时间：
2000-05-01
影响因子：
5.3
通讯作者：
Liu, CL
中科院分区：
文献类型：
--
作者：
Hu, BR;Martone, ME;Liu, CL
含有泛素化蛋白的蛋白质聚集体通常存在于神经退行性疾病中，并被认为是导致神经元变性的原因。在这里，我们报道了短暂性脑缺血导致海马CA1神经元严重的蛋白质聚集。通过乙醇磷钨酸电镜和泛素免疫金电镜观察，我们发现在脑缺血15 min后72小时死亡的CA1神经元中有蛋白聚集体的积累。蛋白质聚集体表现为电子密集的物质团块，泛素染色严重，并与各种细胞内膜结构有关。CA1死亡神经元在再灌注后4小时出现蛋白聚集体，并在再灌注后24和48小时逐渐聚集。然而，在对缺血有抵抗力的齿状回神经元中很少观察到它们。再灌注4小时时，蛋白质聚集主要与体细胞、树突和核膜的胞内囊泡有关。再灌注24小时时，这些聚集体也与线粒体、高尔基体和树突质膜相关。高分辨率共聚焦显微镜进一步证明，含有泛素的蛋白聚集体在所有CA1死亡神经元中持续和逐渐积累，但在该模型中存活的神经元群体中却没有。我们得出结论，蛋白质在海马神经元中严重聚集，易受短暂性脑缺血的影响。我们假设蛋白质聚集体的积累导致缺血性神经元死亡。
Protein aggregates containing ubiquitinated proteins are commonly present in neurodegenerative disorders and have been considered to cause neuronal degeneration. Here, we report that transient cerebral ischemia caused severe protein aggregation in hippocampal CA1 neurons. By using ethanolic phosphotungstic acid electron microscopy (EM) and ubiquitin immunogold EM, we found that protein aggregates were accumulated in CA1 neurons destined to die 72 hr after 15 min of cerebral ischemia. Protein aggregates appeared as clumps of electron-dense materials that stained heavily for ubiquitin and were associated with various intracellular membranous structures. The protein aggregates appeared at 4 hr and progressively accumulated at 24 and 48 hr of reperfusion in CA1 dying neurons. However, they were rarely observed in dentate gyrus neurons that were resistant to ischemia. At 4 hr of reperfusion, protein aggregates were mainly associated with intracellular vesicles in the soma and dendrites, and the nuclear membrane. By 24 hr of reperfusion, the aggregates were also associated with mitochondria, the Golgi apparatus, and the dendritic plasmalemma. High-resolution confocal microscopy further demonstrated that protein aggregates containing ubiquitin were persistently and progressively accumulated in all CA1 dying neurons but not in neuronal populations that survive in this model. We conclude that proteins are severely aggregated in hippocampal neurons vulnerable to transient brain ischemia. We hypothesize that the accumulation of protein aggregates cause ischemic neuronal death.