Molecular mechanisms underlying myocardial hypertrophy induced by ischemia : correlation between changes in intracellular ion concentration and those in expression of immediate-early genes.

缺血引起的心肌肥大的分子机制：细胞内离子浓度变化与立即早期基因表达变化之间的相关性。

• 批准号: 04670518
• 负责人: TAKAHASHI Toshiyuki
• 金额: $ 1.34万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04670518/
• 关键词: Cardiac myocyte; Myocardial ischemia; Metabolic inhibition; Myocardial hypertrophy; Intracellular Ca^<2+>-handling; Immediate-early gene expression; RNA blot analysis; MAP kinase activity; プロテイン・キナーゼ; ノーザン・ブロット解析

Recent studies have revealed that in many types of cells including cardiac myocytes immediate-early genes (IEG) and/or protein kinase cascade play important roles in recovering or adapting to various stresses or growth stimuli. In order to investigate how cardiac myocytes recover from a brief period of ischemia, we used a metabolic inhibition (MI) model, one of in vitro ischemia models, of chick embryo (10-day-old) ventricular myocytes to examine the induction of c-jun mRNA and the activity of mitogen-activated protein (MAP) kinase. We studied the levels of c-jun mRNA (RNA blot analysis), MAP kinase activity (in-gel kinase assay) and [Ca^<2+>] i (measured with indo-1) during MI using 1 mM sodium cyanide and 20 mM 2-deoxy-d-glucose and also during the recovery from MI.The relative abundance of c-jun mRNA (determined by laser densitometry) remained unchanged during MI of 30 min, but increased significantly during the recovery phase at 30,60,90,120 min (3.0,4.7,2.4,1.9-fold induction as c … More ompared with the pre-MI controls, respectively). When the cells were pretreated with 100 mM of H7, one of the potent protein kinase C inhibitors, the induction of mRNA encoding c-jun at 60 min. during the recovery phase was markedly suppressed (95% reduction of the levelos of c-jun mRNA at 60 min during the recovery without H-7). Pretreatment of the cardiac myocytes with 2 mM EGTA completely inhibited the increase in [Ca^<2+>] i during MI and [Ca^<2+>] i was kept at very lower level (184<plus-minus>26 nM at 30 min. during MI,n=3). This EGTA-pretreatment reduced the levels of c-jun mRNA by 42% (p<0.01, n=3) at 60 min. during recovery from MI of 30 min. as compared with those without EGTA.MAP kinase activity was also unchanged during MI,but significantly increased at 5,10,15 min during the recovery phase (3.0,4.1,3.4-fold increase as compared with the pre-MI controls, respecitively). Thus, these data suggest that IEG c-jun as well as MAP kinase may play significant roles in recovery of cardiac myocytes from a brief period of ischemia. This augmentation of c-jun expression may need the activation of protein kinase C,and to some extent, intracellular Ca^<2+>. Less

最近的研究表明，在包括心肌细胞在内的许多类型的细胞中，立即早期基因（IEG）和/或蛋白激酶级联在恢复或适应各种应激或生长刺激中发挥着重要作用。为了研究心肌细胞如何从短暂的缺血中恢复，我们使用鸡胚（10日龄）心室肌细胞的代谢抑制（MI）模型（体外缺血模型之一）来检查c-jun mRNA的诱导和丝裂原激活蛋白（MAP）激酶的活性。我们使用 1 mM 氰化钠和 20 mM 2-脱氧-d-葡萄糖研究了 MI 期间以及 MI 恢复期间的 c-jun mRNA 水平（RNA 印迹分析）、MAP 激酶活性（凝胶内激酶测定）和 [Ca^2+] i（用 indo-1 测量）。c-jun mRNA 的相对丰度（通过激光光密度测定法测定）保持不变 在 30 分钟的 MI 期间没有变化，但在 30、60、90、120 分钟的恢复阶段显着增加（与 MI 前对照相比，分别诱导了 3.0、4.7、2.4、1.9 倍）。当用 100 mM H7（一种有效的蛋白激酶 C 抑制剂）预处理细胞时，在 60 分钟时诱导编码 c-jun 的 mRNA。在恢复阶段，c-jun mRNA 水平明显受到抑制（在没有 H-7 的恢复过程中，60 分钟时 c-jun mRNA 水平降低了 95%）。用2 mM EGTA预处理心肌细胞完全抑制了MI期间[Ca ^ 2+ ] i 的增加，并且[Ca ^ 2+ ] i 保持在非常低的水平(MI期间30分钟时184±26 nM，n＝3)。 60 分钟时，EGTA 预处理使 c-jun mRNA 水平降低了 42%（p<0.01，n=3）。 MI 恢复期间 30 分钟。 MI期间MAP激酶活性也没有变化，但在恢复期5、10、15分钟显着增加（分别与MI前对照相比增加3.0、4.1、3.4倍）。因此，这些数据表明 IEG c-jun 以及 MAP 激酶可能在心肌细胞从短暂缺血期的恢复中发挥重要作用。 c-jun表达的增强可能需要蛋白激酶C的激活，并且在某种程度上需要细胞内Ca 2+ 的激活。较少的