Dynein- and activity-dependent retrograde transport of autophagosomes in neuronal axons
Dynein- and activity-dependent retrograde transport of autophagosomes in neuronal axons
复制标题
DOI：
10.4161/auto.6.3.11262
复制
发表时间：
2010-04-01
期刊：
影响因子：
13.3
通讯作者：
Yuzaki, Michisuke
中科院分区：
文献类型：
--
作者：
Katsumata, Kiyoshi;Nishiyama, Jun;Yuzaki, Michisuke
轴突内自噬体的积累经常在与各种神经系统疾病相关的轴突病中观察到，包括兴奋性毒性损伤后的轴突病。然而，轴突中自噬体的生命周期还不清楚。在本研究中，我们使用GFP-LC 3转基因小鼠小脑颗粒细胞的微植培养物，对确定的轴突中的LC 3阳性点进行延时成像。由于这些GFP-LC 3点从未在Atg 5无效背景下的颗粒细胞中观察到，因此认为它们代表自噬体。在生理条件下，自噬体呈现双向跳跃运动，偏向一个方向。这种矢量运动在很大程度上被动力蛋白运动抑制剂EHNA（β-9-[3-（2-羟基壬基）]腺嘌呤）阻断，这表明自噬体向大多数溶酶体所在的索马移动。有趣的是，谷氨酸类似物N-甲基-D-天冬氨酸（NMDA）作为兴奋性毒素的应用增加了轴突中自噬体的数量，而它并没有显着改变其运动特性。这些结果表明，自噬体在轴突中发挥重要作用，并在生理和病理条件下动态调节。
The accumulation of autophagosomes within axons is often observed in axonopathies associated with various neurological disorders, including those following excitotoxic insults. Nevertheless, the life cycle of autophagosomes in axons is not well understood. In the present study, we used microexplant cultures of cerebellar granule cells from GFP-LC3 transgenic mice to perform time-lapse imaging of LC3-positive dots in identified axons. Since these GFP-LC3 dots were never observed in granule cells on an Atg5-null background, they were considered to represent autophagosomes. Under physiological conditions, the autophagosomes showed bidirectional and saltatory movement with a bias towards one direction. Such vectorial movement was largely blocked by the dynein motor inhibitor EHNA (erythro-9-[3-(2-hydroxynonyl)] adenine), suggesting that the autophagosomes moved towards the soma, where most lysosomes are located. Interestingly, the application of the glutamate analog N-methyl-D-aspartic acid (NMDA) as an excitotoxin increased the number of autophagosomes in axons, while it did not significantly change its movement characteristics. These results suggest that autophagosomes play important roles in axons and are dynamically regulated under physiological and pathological conditions.