Akt promotes survival of cardiomyocytes in vitro and protects against ischemia-reperfusion injury in mouse heart
Akt promotes survival of cardiomyocytes in vitro and protects against ischemia-reperfusion injury in mouse heart
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DOI：
10.1161/01.cir.101.6.660
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发表时间：
2000-02-15
期刊：
影响因子：
37.8
通讯作者：
Walsh, K
中科院分区：
文献类型：
--
作者：
Fujio, Y;Nguyen, T;Walsh, K
背景-IGF-1 已被证明可以在梗塞和缺血再灌注损伤的动物模型中保护心肌免于死亡。在本研究中，我们研究了IGF-l调节的蛋白激酶Akt在体外和体内心肌细胞存活中的作用。方法和结果-IGF-1以剂量依赖性方式促进血清剥夺条件下培养的心肌细胞的存活，但对心脏成纤维细胞的存活没有影响，IGF-1对心肌细胞的细胞保护作用被磷脂酰肌醇3-激酶（PI 3-激酶）抑制剂消除渥曼青霉素。在 IGF-1 缺失的情况下，渥曼青霉素对心肌细胞活力没有影响。 IGF-l 介导的细胞保护与渥曼青霉素敏感的 Akt 蛋白激酶活性诱导相关。为了检查 Akt 激活对心肌细胞存活的功能影响，构建了表达野生型、显性失活和组成型活性 Akt 基因的复制缺陷型腺病毒构建体。显性失活 Akt 的转导可阻断 IGF-1 诱导的存活，但在 IGF-1 缺失的情况下对心肌细胞存活没有影响。相比之下，野生型 Akt 的转导在 IGF-I 亚饱和水平下增强了心肌细胞的存活，而在 IGF-1 不存在的情况下，组成型活性 Akt 保护心肌细胞免于凋亡。在体内转导到小鼠心脏后，组成型活性 Akr 保护心肌细胞免受缺血再灌注损伤反应中的凋亡。结论-这些数据是 Akt 在体内发挥促进细胞存活作用的第一个文献，它们表明该途径的激活可能有助于促进患病心脏中的肌细胞存活。
Background-IGF-1 has been shown to protect myocardium against death in animal models of infarct and ischemia-reperfusion injury. In the present study, we investigated the role of the IGF-l-regulated protein kinase Akt in cardiac myocyte survival in vitro and in vivo.Methods and Results-IGF-1 promoted survival of cultured cardiomyocytes under conditions of serum deprivation in a dose-dependent manner but had no effect on cardiac fibroblast survival, The cytoprotective effect of IGF-1 on cardiomyocytes was abrogated by the phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor wortmannin. Wortmannin had no effect on cardiomyocyte viability in the absence of IGF-1. IGF-l-mediated cytoprotection correlated with the wortmannin-sensitive induction of Akt protein kinase activity. To examine the functional consequences of Akt activation in cardiomyocyte survival, replication-defective adenoviral constructs expressing wild-type, dominant-negative, and constitutively active Akt genes were constructed. Transduction of dominant-negative Akt blocked IGF-1-induced survival but had no effect on cardiomyocyte survival in the absence of IGF-1. In contrast, transduction of wild-type Akt enhanced cardiomyocyte survival at subsaturating levels of IGF-I, whereas constitutively active Akt protected cardiomyocytes from apoptosis in the absence of IGF-1, After transduction into the mouse heart in vivo, constitutively active Akr protected against myocyte apoptosis in response to ischemia-reperfusion injury.Conclusions-These data are the first documentation that Akt functions to promote cellular survival in vivo, and they indicate that the activation of this pathway may be useful in promoting myocyte survival in the diseased heart.