A role of reactive oxygen species in apoptotic activation of volume-sensitive Cl- channel
A role of reactive oxygen species in apoptotic activation of volume-sensitive Cl- channel
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DOI：
10.1073/pnas.0401604101
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发表时间：
2004-04-27
影响因子：
11.1
通讯作者：
Okada, Y
中科院分区：
文献类型：
--
作者：
Shimizu, T;Numata, T;Okada, Y
凋亡体积减少是触发细胞发生凋亡的关键事件，并且由主要由增加的K+和Cl-电导引起的离子流出诱导。在这里，我们证明了在人上皮细胞HeLa细胞中，细胞因子和死亡受体介导的凋亡诱导剂[星形孢菌素和Fas配体或肿瘤坏死因子（TNF）-α]快速激活Cl-电流，其显示出体积敏感性外向整流Cl-通道电流的表型特性，包括外向整流，在大正电位下的电压依赖性失活门控，渗透收缩抑制，对经典的Cl-通道阻滞剂的敏感性和对胞浆ATP的依赖性。星形孢菌素，而不是Fas配体或TNF-α，迅速（30分钟内）增加细胞内活性氧（ROS）的水平。ROS清除剂和NAD（P）H氧化酶抑制剂阻断了星形孢菌素对电流的激活，但不阻断Fas配体或TNF-α对电流的激活。活性氧清除剂也抑制凋亡体积减少，半胱天冬酶-3激活，和星形孢菌素诱导的凋亡细胞死亡。因此，可以得出结论，凋亡触发阴离子电导进行的体积敏感性向外整流Cl-通道和通道激活的凋亡刺激与星形孢菌素，但不是与Fas配体或TNF-α，是由ROS介导的。
Apoptotic volume decrease is a pivotal event triggering a cell to undergo apoptosis and is induced by ionic effluxes resulting mainly from increased K+ and Cl- conductances. Here, we demonstrate that in human epithelia HeLa cells both mitochondrion- and death receptor-mediated apoptosis inducers [staurosporine and Fas ligand or tumor necrosis factor (TNF)-alpha] rapidly activate Cl- currents that show properties phenotypical of volume-sensitive outwardly rectifying Cl- channel currents, including outward rectification, voltage-dependent inactivation gating at large positive potentials, inhibition by osmotic shrinkage, sensitivity to classic Cl- channel blockers, and dependence on cytosolic ATP. Staurosporine, but not Fas ligand or TNF-alpha, rapidly (within 30 min) increased the intracellular level of reactive oxygen species (ROS). A ROS scavenger and an NAD(P)H oxidase inhibitor blocked the current activation by staurosporine but not by Fas ligand or TNF-alpha. A ROS scavenger also inhibited apoptotic volume decrease, caspase-3 activation, and apoptotic cell death induced by staurosporine. Thus, it is concluded that an apoptosis-triggering anion conductance is carried by the volume-sensitive outwardly rectifying Cl- channel and that the channel activation on apoptotic stimulation with staurosporine, but not with Fas ligand or TNF-alpha, is mediated by ROS.