The actin cytoskeleton and cytotoxic T lymphocytes: evidence for multiple roles that could affect granule exocytosis-dependent target cell killing
The actin cytoskeleton and cytotoxic T lymphocytes: evidence for multiple roles that could affect granule exocytosis-dependent target cell killing
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DOI：
10.1113/jphysiol.2002.033522
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发表时间：
2003-03-15
影响因子：
5.5
通讯作者：
Zweifach, A
中科院分区：
文献类型：
--
作者：
Lyubchenko, TA;Wurth, GA;Zweifach, A
细胞毒性 T 淋巴细胞 (CTL) 用于杀死病毒感染、移植或肿瘤靶标的一种重要机制是含有细胞毒性剂（如穿孔素和颗粒酶）的颗粒的胞吐作用。颗粒胞吐作用依赖性靶细胞杀伤是一个复杂的过程，涉及初始 T 细胞受体 (TCR) 依赖性信号传导，包括 Ca2+ 流入和蛋白激酶 C 的激活、用于将 CTL 与靶标结合的形状变化，以及最后在与靶细胞接触部位的裂解颗粒的胞吐作用。尽管有理由提出裂解过程中的多个步骤可能涉及 CTL 的肌动蛋白细胞骨架，但很少有研究研究过这个问题，而且那些研究不允许确定所涉及的具体步骤。我们使用强效的透膜肌动蛋白细胞骨架修饰药物 jasplakinolide 和 latrunculin A 来研究特定过程的肌动蛋白依赖性，这些过程预计对颗粒胞吐作用依赖性杀伤非常重要。我们使用 TALL-104 人类白血病 CTL 作为模型系统获得的结果与以下观点一致：TCR/CD3 依赖性信号传导、钙库依赖性 Ca2+ 流入的激活和 CTL 形状变化需要功能性肌动蛋白细胞骨架。当用固相抗 CD3 抗体刺激细胞时，用 jasplakinolide 或 latrunculin A 处理可消除颗粒胞吐作用。然而，当细胞以绕过 TCR/CD3 依赖性信号传导的方式受到刺激时，颗粒胞吐作用没有显着改变，这表明肌动蛋白细胞骨架不能作为胞吐作用的屏障。
One important mechanism cytotoxic T lymphocytes (CTLs) use to kill virus-infected, transplanted or tumour targets is exocytosis of granules that contain cytotoxic agents such as perforin and granzymes. Granule exocytosis-dependent target cell killing is a complex process, involving initial T-cell receptor (TCR)-dependent signalling that includes Ca2+ influx and activation of protein kinase C, shape changes that serve to bind the CTL to the target and, finally, exocytosis of lytic granules at the site of contact with the target cell. Although there is reason to propose that multiple steps in the lytic process could involve the actin cytoskeleton of CTLs, few studies have examined this issue, and those that have do not allow the specific step (s) involved to be determined. We have used the potent membrane-permeant actin cytoskeleton-modifying drugs jasplakinolide and latrunculin A to investigate the actin dependence of defined processes that are expected to be important for granule exocytosis-dependent killing. Our results, obtained using TALL-104 human leukaemic CTLs as a model system, are consistent with the idea that a functional actin cytoskeleton is required for TCR/CD3-dependent signalling, for activation of store-dependent Ca2+ influx and for CTL shape changes. When cells were stimulated with solid-phase anti-CD3 antibodies, treatment with either jasplakinolide or latrunculin A abolished granule exocytosis. However, when cells were stimulated in a manner that bypasses TCR/CD3-dependent signalling, granule exocytosis was not significantly altered, suggesting that the actin cytoskeleton does not function as a barrier to exocytosis.