Oxidative stress activates extracellular signal-regulated kinases through Src and ras in cultured cardiac myocytes of neonatal rats
Oxidative stress activates extracellular signal-regulated kinases through Src and ras in cultured cardiac myocytes of neonatal rats
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DOI：
10.1172/jci119709
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发表时间：
1997-10-01
影响因子：
15.9
通讯作者：
Yazaki, Y
中科院分区：
文献类型：
--
作者：
Aikawa, R;Komuro, I;Yazaki, Y
越来越多的证据表明，氧化应激在缺血/再灌流过程中会导致心脏损伤。细胞外信号调节蛋白激酶(ERKs)在细胞功能的许多方面发挥着关键作用，并在某些类型的细胞中被氧化应激激活。在这项研究中，我们研究了氧化应激诱导的信号转导通路导致培养的新生大鼠心肌细胞ERKs的激活，并确定了它们在氧化应激诱导的心肌细胞损伤中的作用。在心肌细胞中，ERK被过氧化氢(H_2O_2)瞬时激活，且呈浓度依赖性。特异性酪氨酸激酶抑制剂金雀异黄素可抑制H_2O_2诱导的ERK激活，而蛋白激酶A、C或钙离子螯合剂的抑制剂对此无影响。当SRC家族酪氨酸激酶的负调控因子CSK、Ras或Raf-1激酶的显性负向突变体CSK过度表达时，H_2O_2不能激活转染型ERK2，H_2O_2可使末端脱氧核苷酸转移酶介导的dUTP缺口末端标记阳性的细胞数增加，并诱导DNA梯带的形成和CPP32的激活，提示H_2O_2诱导心肌细胞凋亡。当PD98059选择性地抑制H_2O_2诱导的ERKs的激活时，出现凋亡性死亡的心肌细胞数增加。这些结果表明，Src家族酪氨酸激酶、Ras和Raf-1在羟基自由基激活ERK过程中起关键作用，ERKs的激活可能在保护心肌细胞免受氧化应激所致的凋亡性死亡中起重要作用。
A growing body of evidence has suggested that oxidative stress causes cardiac injuries during ischemia/reperfusion. Extracellular signal-regulated kinases (ERKs) have been reported to play pivotal roles in many aspects of cell functions and to be activated by oxidative stress in some types of cells. In this study, we examined oxidative stress-evoked signal transduction pathways leading to activation of ERKs in cultured cardiomyocytes of neonatal rats, and determined their role in oxidative stress-induced cardiomyocyte injuries. ERKs were transiently and concentration-dependently activated by hydrogen peroxide (H2O2) in cardiac myocytes. A specific tyrosine kinase inhibitor, genistein, suppressed H2O2-induced ERK activation, while inhibitors of protein kinase A and C or Ca2+ chelators had no effects on the activation, When CSK, a negative regulator of Src family tyrosine kinases, or dominant-negative mutant of Ras or of Raf-1 kinase was overexpressed, activation of transfected ERK2 by H2O2 was abolished, The treatment with H2O2 increased the number of cells stained positive by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, and induced formation of DNA ladder and activation of CPP32, suggesting that H2O2 induced apoptosis of cardiac myocytes. When H2O2-induced activation of ERKs was selectively inhibited by PD98059, the number of cardiac myocytes which showed apoptotic death was increased, These results suggest that Src family tyrosine kinases, Ras and Raf-1 are critical for ERK activation by hydroxyl radicals and that activation of ERKs may play an important role in protecting cardiac myocytes from apoptotic death following oxidative stress.