Preconditioning blocks cardiocyte apoptosis:: role of KATP channels and PKC-ε
Preconditioning blocks cardiocyte apoptosis:: role of KATP channels and PKC-ε
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DOI：
10.1152/ajpheart.00348.2001
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发表时间：
2002-04-01
影响因子：
4.8
通讯作者：
Yao, ZH
中科院分区：
文献类型：
--
作者：
Liu, HP;Zhang, HY;Yao, ZH
本研究的目的是确定预适应是否能阻断心肌细胞的凋亡，并确定线粒体ATP敏感性钾通道(K-ATP)和蛋白激酶C epsilon异构体(PKC-epsilon)在这一作用中的作用。取10日龄雏鸡胚胎的心室肌细胞。在对照组中，模拟缺血10h后复氧12h，细胞凋亡率为42+/-3%(n=8)。这些结果与DNA梯状条带和TdT介导的dUTP缺口末端标记(TUNEL)实验结果一致。在长时间模拟缺血前，以1min的缺血间隔5min的复氧诱导3个循环的预适应，可显著减弱细胞的凋亡过程(28+/-4%，n=8)。缺血前给予线粒体K-ATP通道开放剂二氮嗪(400mumol/L)，可模拟预适应效应以阻止细胞凋亡(22+/-4%，n=6)。预先给予线粒体K-ATP通道阻断剂5-羟基癸酸(100mumol/L)可取消预适应(42+/-2%，n=6)。此外，在模拟缺血和复氧条件下，给予特异性蛋白激酶C抑制剂GO-6976(0.1mumol/L)或白屈菜红碱(4mumol/L)可阻断预适应和二氮卓的作用。此外，预适应和二氮嗪选择性地激活模拟缺血前颗粒组分中的PKC-epsilon，而不影响总组分、胞浆组分和PKC增量异构体。在模拟缺血和复氧过程中加入特异性PKC激活剂佛波酯12-肉豆蔻酸酯13-醋酸酯(0.2mumol/L)，模拟预适应以阻断细胞凋亡。开放线粒体K-ATP通道可通过激活培养的心肌细胞中的PKC-epsilon来阻断心肌细胞的凋亡。通过这一信号转导途径，预适应可阻断缺血再灌注时的细胞凋亡，保护心功能。
The aims of this study were to determine whether preconditioning blocks cardiocyte apoptosis and to determine the role of mitochondrial ATP-sensitive K+ (K-ATP) channels and the protein kinase C epsilon-isoform (PKC-epsilon) in this effect. Ventricular myocytes from 10-day-old chick embryos were used. In the control series, 10 h of simulated ischemia followed by 12 h of reoxygenation resulted in 42 +/- 3% apoptosis (n = 8). These results were consistent with DNA laddering and TdT-mediated dUTP nick-end labeling (TUNEL) assay. Preconditioning, elicited with three cycles of 1 min of ischemia separated by 5 min of reoxygenation before subjection to prolonged simulated ischemia, markedly attenuated the apoptotic process (28 +/- 4%, n = 8). The selective mitochondrial K-ATP channel opener diazoxide (400 mumol/l), given before ischemia, mimicked preconditioning effects to prevent apoptosis (22 +/- 4%, n = 6). Pretreatment with 5-hydroxydecanoate (100 mumol/l), a selective mitochondrial K-ATP channel blocker, abolished preconditioning (42 +/- 2%, n = 6). In addition, the effects of preconditioning and diazoxide were blocked with the specific PKC inhibitors Go-6976 (0.1 mumol/l) or chelerythrine (4 mumol/l), given at simulated ischemia and reoxygenation. Furthermore, preconditioning and diazoxide selectively activated PKC-epsilon in the particulate fraction before simulated ischemia without effect on the total fraction, cytosolic fraction, and PKC delta-isoform. The specific PKC activator phorbol 12-myristate 13-acetate (0.2 mumol/l), added during simulated ischemia and reoxygenation, mimicked preconditioning to block apoptosis. Opening mitochondrial K-ATP channels blocks cardiocyte apoptosis via activating PKC-epsilon in cultured ventricular myocytes. Through this signal transduction, preconditioning blocks apoptosis and preserves cardiac function in ischemia-reperfusion.