Autophagy plays a protective role as an anti‐oxidant system in human T cells and represents a novel strategy for induction of T‐cell apoptosis
Autophagy plays a protective role as an anti‐oxidant system in human T cells and represents a novel strategy for induction of T‐cell apoptosis
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DOI：
10.1002/eji.201344248
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发表时间：
2014-08
影响因子：
5.4
通讯作者：
R. Watanabe;H. Fujii;T. Shirai;S. Saito;T. Ishii;H. Harigae
中科院分区：
文献类型：
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作者：
R. Watanabe;H. Fujii;T. Shirai;S. Saito;T. Ishii;H. Harigae
自噬是一种细胞内降解系统，对T细胞的存活起着重要作用。然而，原代人类T细胞自噬和细胞死亡的确切机制尚不清楚，因为监测少量原代人类细胞自噬的方法仍然存在争议。我们建立了一种利用逆转录病毒GFP-LC3表达系统评估激活的人T细胞自噬的新方法。我们发现自噬是在TCR刺激后被诱导的，并且自噬缺陷的幼稚CD4+T细胞通过内在的凋亡途径易受凋亡的影响。自噬缺陷T细胞的凋亡增加是由于有丝分裂吞噬功能受损导致的ROS积累所致。我们还证明，效应记忆的CD4+T细胞的自噬活性低于幼稚的CD4+T细胞，这是由于ROS增加而促进了它们的凋亡。此外，阻断自噬增加了激活T细胞内线粒体的体积和ROS水平。这些结果表明，自噬作为一种抗氧化系统在激活的人类T细胞中具有保护作用。自噬阻断剂和线粒体电子传递链抑制剂联合应用对T细胞死亡具有协同作用，有望成为一种诱导T细胞凋亡的新策略。
Autophagy is an intracellular degradation system that plays an important role in T‐cell survival. However, the precise mechanism linking autophagy and cell death in primary human T cells is unclear because methods for monitoring autophagy in small numbers of primary human cells remain controversial. We established a novel method for assessing autophagy in activated human T cells using a retroviral GFP–LC3 expression system. We found that autophagy was induced after TCR stimulation and that autophagy‐defective naïve CD4+ T cells were susceptible to apoptosis through the intrinsic apoptotic pathway. Enhanced apoptosis of autophagy‐defective T cells resulted from accumulation of ROS due to impaired mitophagy. We also demonstrated that effector memory CD4+ T cells had lower autophagic activity than naïve CD4+ T cells, which contributed to their enhanced apoptosis due to increased ROS. Moreover, blocking autophagy increased intracellular mitochondrial volume and ROS levels in activated T cells. These results suggest a protective role of autophagy as an anti‐oxidant system in activated human T cells. The combination of an autophagy blocker and a mitochondrial electron transport chain inhibitor has a synergistic effect on T‐cell death, which could be a novel strategy for induction of T‐cell apoptosis.