Endoplasmic reticulum Ca2+ depletion induces endothelial cell apoptosis independently of caspase-12
Endoplasmic reticulum Ca2+ depletion induces endothelial cell apoptosis independently of caspase-12
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DOI：
10.1016/j.cardiores.2005.11.023
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发表时间：
2006-03-01
影响因子：
10.8
通讯作者：
Hayashi, H
中科院分区：
文献类型：
--
作者：
Nakano, T;Watanabe, H;Hayashi, H
目的：内皮细胞凋亡被认为是动脉粥样硬化发展的起始步骤。最近的研究表明，内质网（ER）的Ca ~（2+）含量的耗竭在细胞凋亡中起着重要作用。Caspase-12是内质网应激诱导细胞凋亡的关键信号。然而，目前尚不清楚ER Ca 2+的耗竭是否与内皮细胞中的caspase-12信号转导有关。方法：采用Fura-2/AM法测定原代培养的猪主动脉内皮细胞胞浆内Ca 2+浓度（[Ca 2+]（i）），并与Caspase-12酶切进行比较。结果：毒胡萝卜素（5 μ M），ER Ca 2 +-ATP酶的抑制剂，耗尽ER Ca 2+含量，增加[Ca 2 +]（i）切割caspase-12，诱导细胞凋亡。缓激肽（10 nM）也增加[Ca 2 +]（i），但不裂解caspase-12或诱导细胞凋亡。然而，当细胞内Ca 2+与BAPTA/AM（100 μ M）螯合时，缓激肽引起ER Ca 2+耗竭和细胞凋亡，而不伴随caspase-12裂解。一种非选择性半胱天冬酶抑制剂，z-VAD。（100 μ M），抑制细胞凋亡和切割的半胱天冬酶-12刺激毒胡萝卜素，而钙蛋白酶抑制剂，MDL 28170（120 μ M），抑制caspase-12裂解，但不抑制凋亡。因此，细胞内Ca 2+浓度的增加不足以诱导内皮细胞的凋亡，ER Ca ~（2+）耗竭似乎不依赖于caspase-12而诱导细胞凋亡。(c)2005年欧洲心脏病学会。Elsevier B. V.出版，保留所有权利。
Objective: Apoptosis of endothelial cells is considered an initial step in the development of atherosclerosis. Recent studies have indicated that depletion of the endoplasmic reticulum (ER) Ca2+ content plays an important role in apoptosis. Caspase-12 is a key signal in ER stress-induced apoptosis. However, it is not known whether the depletion of ER Ca2+ is linked to caspase-12 signalling in endothelial cells. Here we have investigated the interaction of Ca2+ signalling and caspase-12 cleavage in apoptosis of endothelial cells.Methods: Cytosolic Ca2+ concentration ([Ca 2+](i)) of primary porcine aortic endothelial cells was measured using fura-2/AM. Apoptosis was assessed by DNA fragmentation, and cleavage of caspase-12 using Western blotting techniques.Results: Thapsigargin (5 mu M), an inhibitor of the ER Ca2+-ATPase, depleted ER Ca2+ content, increased [Ca2+](i) cleaved caspase-12, and induced apoptosis. Bradykinin (10 nM) also increased [Ca2+](i) but did not cleave caspase-12 or induce apoptosis. However, when intracellular Ca2+ was chelated with BAPTA/AM (100 mu M), bradykinin caused ER Ca2+ depletion and apoptosis without accompanying caspase-12 cleavage. A non-selective caspase inhibitor, z-VAD.fmk (100 mu M), inhibited apoptosis and cleavage of caspase-12 stimulated by thapsigargin, while a calpain inhibitor, MDL 28170 (120 mu M), inhibited caspase-12 cleavage but not apoptosis.Conclusions: Thus, increases in intracellular Ca2+ concentration are not sufficient for the induction of apoptosis in endothelial cells, and ER Ca2+ depletion appears to induce apoptosis independently of caspase-12. (c) 2005 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.