Involvement of intracellular Ca2+ levels in nonsteroidal anti-inflammatory drug-induced apoptosis
Involvement of intracellular Ca2+ levels in nonsteroidal anti-inflammatory drug-induced apoptosis
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DOI：
10.1074/jbc.m502956200
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发表时间：
2005-09-02
影响因子：
4.8
通讯作者：
Mizushima, T
中科院分区：
文献类型：
--
作者：
Tanaka, K;Tomisato, W;Mizushima, T
我们最近报道了非甾体抗炎药（NSAID）诱导的胃病变涉及NSAID诱导的胃粘膜细胞凋亡，这反过来涉及内质网应激反应，特别是CCAAT/增强结合蛋白同源转录因子（CHOP）的上调。在本研究中，我们研究了非甾体抗炎药诱导胃粘膜细胞原代培养细胞凋亡的分子机制。各种非甾体抗炎药均表现出膜透性活性与其诱导细胞凋亡活性相关。各种非甾体抗炎药，特别是塞来昔布，也增加细胞内Ca2+水平。这种增加伴随着细胞的K+外排，当细胞外Ca2+耗尽时几乎不存在。这些数据表明，在非甾体抗炎药存在下观察到的细胞内Ca2+水平的增加是由于刺激Ca2+通过细胞质膜流入，这是由它们的膜透性活性引起的。细胞内Ca2+螯合剂部分抑制塞来昔布诱导的线粒体细胞色素c的释放，降低塞来昔布诱导的线粒体膜电位下降的幅度，抑制塞来昔布诱导的凋亡细胞死亡。因此，细胞内Ca2+水平的增加可能与塞来昔布诱导的线粒体功能障碍和由此导致的细胞凋亡有关。钙蛋白酶（Ca2+依赖性半胱氨酸蛋白酶）的抑制剂，在塞来昔布存在下部分抑制线粒体功能障碍和细胞凋亡。细胞内Ca2+螯合剂部分抑制塞来昔布依赖性CHOP-诱导，但不受钙蛋白酶抑制剂的抑制。这些结果提示Ca2+刺激的钙蛋白酶活性和CHOP表达在塞来昔布诱导的胃粘膜细胞凋亡中起重要作用。
We recently reported that nonsteroidal anti- inflammatory drug ( NSAID)- induced gastric lesions involve NSAID- induced apoptosis of gastric mucosal cells, which in turn involves the endoplasmic reticulum stress response, in particular the up- regulation of CCAAT/ enhancerbinding protein homologous transcription factor ( CHOP). In this study, we have examined the molecular mechanism governing this NSAID- induced apoptosis in primary cultures of gastric mucosal cells. Various NSAIDs showed membrane permeabilization activity that correlated with their apoptosis- inducing activity. Various NSAIDs, particularly celecoxib, also increased intracellular Ca2+ levels. This increase was accompanied by K+ efflux from cells and was virtually absent when extracellular Ca2+ had been depleted. These data indicate that the increase in intracellular Ca2+ levels that is observed in the presence of NSAIDs is due to the stimulation of Ca2+ influx across the cytoplasmic membrane, which results from their membrane permeabilization activity. An intracellular Ca2+ chelator partially inhibited celecoxib- induced release of cytochrome c from mitochondria, reduced the magnitude of the celecoxib- induced decrease in mitochondrial membrane potential and inhibited celecoxib- induced apoptotic cell death. It is therefore likely that an increase in intracellular Ca2+ levels is involved in celecoxib- induced mitochondrial dysfunction and the resulting apoptosis. An inhibitor of calpain, a Ca2+ dependent cysteine protease, partially suppressed mitochondrial dysfunction and apoptosis in the presence of celecoxib. Celecoxib- dependent CHOP- induction was partially inhibited by the intracellular Ca2+ chelator but not by the calpain inhibitor. These results suggest that Ca2+- stimulated calpain activity and CHOP expression play important roles in celecoxib- induced apoptosis in gastric mucosal cells.