Endoplasmic reticulum stress-induced death of mouse embryonic fibroblasts requires the intrinsic pathway of apoptosis
Endoplasmic reticulum stress-induced death of mouse embryonic fibroblasts requires the intrinsic pathway of apoptosis
复制标题
DOI：
10.1074/jbc.m700077200
复制
发表时间：
2007-05-11
影响因子：
4.8
通讯作者：
Flavell, Richard A.
中科院分区：
文献类型：
--
作者：
Masud, Ali;Mohapatra, Alexander;Flavell, Richard A.
胱天蛋白酶家族的成员对于许多凋亡程序是必需的。我们研究了小鼠胚胎成纤维细胞（MEFs）缺乏半胱天冬酶3和7和半胱天冬酶9，以确定这些蛋白酶在内质网（ER）应激诱导的细胞凋亡的作用。caspase 3（-/-）/caspase 7（-/-）和caspase 9（-/-）MEFs对通过ER应激诱导的细胞毒性具有抗性，并且未能表现出凋亡形态。具体而言，细胞内钙离子增加诱导的细胞凋亡仅依赖于半胱天冬酶3和9，而ER功能破坏诱导的细胞凋亡还依赖于半胱天冬酶7。Caspase 3（-/-）/caspase 7（-/-）和caspase 9（-/-）MEFs也表现出线粒体膜电位损失减少，这与caspase 3（-/-）/caspase 7（-/-）细胞中caspase 9加工改变、caspase 11诱导增加和caspase 12加工减少相关。此外，ER功能的破坏足以诱导裂解的caspase 3和7在重膜隔室中的积累，这表明caspase 12加工的潜在机制及其在死亡途径中作为放大器的作用。Caspase 8（-/-）MEFs对ER应激诱导的细胞毒性没有抵抗力，并且在ER应激诱导后没有观察到caspase 8的加工。因此，这项研究表明，在内质网应激诱导的细胞凋亡的内在途径中，caspase 3和9的需求和关键作用。
Members of the caspase family are essential for many apoptotic programs. We studied mouse embryonic fibroblasts (MEFs) deficient in caspases 3 and 7 and in caspase 9 to determine the role of these proteases in endoplasmic reticulum (ER) stress-induced apoptosis. Both caspase 3(-/-)/caspase 7(-/-) and caspase 9(-/-) MEFs were resistant to cytotoxicity induced via ER stress and failed to exhibit apoptotic morphology. Specifically, apoptosis induced by increased intracellular calcium was shown to depend only on caspases 3 and 9, whereas apoptosis induced by disruption of ER function depended additionally on caspase 7. Caspase 3(-/-)/caspase 7(-/-) and caspase 9(-/-) MEFs also exhibited decreased loss of mitochondrial membrane potential, which correlated with altered caspase 9 processing, increased induction of procaspase 11, and decreased processing of caspase 12 in caspase 3(-/-)/caspase 7(-/-) cells. Furthermore, disruption of ER function was sufficient to induce accumulation of cleaved caspase 3 and 7 in a heavy membrane compartment, suggesting a potential mechanism for caspase 12 processing and its role as an amplifier in the death pathway. Caspase 8(-/-) MEFs were not resistant to ER stress-induced cytotoxicity, and processing of caspase 8 was not observed upon induction of ER stress. This study thus demonstrates a requirement for caspases 3 and 9 and a key role for the intrinsic pathway in ER stress-induced apoptosis.