Molecular Signals Against Beta-AR-Stimulated Apoptosis

描述(申请人提供)：交感神经活动的增加是一种 心力衰竭患者的中心特征。因以下原因引起的心肌细胞损失 细胞凋亡被认为在肿瘤的发展过程中起着重要作用。 心力衰竭。我们已经证明，去甲肾上腺素通过f3-肾上腺素能 受体(p3-AR)刺激成年大鼠心肌细胞凋亡 (ARVM)，刺激β-AR和抑制性G蛋白(GI)具有保护作用 抗B1-AR刺激的细胞凋亡。我们还展示了Beta-AR激活 丝裂原活化蛋白激酶(MAPKs)超家族(包括p38、JNKs 和Erki/2)，而Gi介导的p38的激活对 β-AR刺激细胞凋亡。其他人提供的证据表明，G蛋白 偶联受体(GPCR)通过激活刺激焦点黏附组装 小的GTP结合蛋白(RhoA、Rac1和CDC42)的结合，从而激活MAPK。 小分子GTP结合蛋白通过肌动蛋白激活粘着斑蛋白 聚合和整合素聚集。我们最近的初步数据表明 刺激β1整合素信号和RhoA可保护ARVM β-AR刺激细胞凋亡。粘着斑激酶(FAK)，一种重要的蛋白激酶 焦点黏附复合体，在β-AR刺激和抑制时被激活 焦点黏附复合体的另一种酶SRC激酶增加 β-AR刺激细胞凋亡。这些观察结果导致了我们的假设 β1整合素和小GTP结合蛋白的激活，通过共同的 涉及粘着斑蛋白的信号通路起到保护作用 在β-AR刺激的细胞凋亡和心肌重塑中。为了测试这一点 假设，我们将使用杂合基因敲除小鼠来检测Beta1整合素和ARVM 使用腺病毒感染。目标1将在体内确定Beta1的作用 整合素在β-AR诱导的细胞凋亡和心肌重塑中的作用 杂合子β1整合素基因敲除小鼠。目标2将通过以下方式定义该机制 哪种Beta1整合素信号提供对β-AR刺激的保护 细胞凋亡。AIMS 3和4将定义小GTP结合蛋白的作用 (RhoA和RACI)在β-AR刺激的细胞凋亡和信号转导中。目标5将 确定GI蛋白的作用并确定GI亚型参与 激活小的GTP结合蛋白和FAK。这些研究将取得进展 我们对刺激β-AR激活的信号通路的理解 和β1整合素，及其在调控心肌细胞凋亡中的作用 和心肌重塑。

DESCRIPTION (provided by applicant): An increase in sympathetic activity is a central feature in patients with heart failure. Cardiac myocyte loss due to apoptosis has been proposed to play an important role in the progression of heart failure. We have shown that norepinephrine, acting via the f3-adrenergic receptor (p3-AR), stimulates apoptosis in adult rat ventricular myocytes (ARVM), and the stimulation of Beta-AR and inhibitory G-protein (Gi) protects against B1-AR-stimulated apoptosis. We have also shown that Beta-AR activates mitogen-activated protein kinase (MAPKs) superfamily (which includes p38, JNKs and ERKI/2), and Gi-mediated activation of p38 protects against Beta-AR-stimulated apoptosis. Others have provided evidence that the G-protein coupled receptors (GPCR) stimulate focal adhesion assembly via the activation of small GTP-binding proteins (RhoA, racl and cdc42), thereby activating MAPKs. Small GTP-binding proteins activate focal adhesion complex proteins by actin polymerization and integrin clustering. Our recent preliminary data suggest that stimulation of beta1 integrin signaling and RhoA protects ARVM against beta-AR-stimulated apoptosis. Focal adhesion kinase (FAK), an important kinase of focal adhesion complex, is activated upon Beta-AR stimulation and inhibition of Src kinase, another enzyme of focal adhesion complex, increases beta-AR-stimulated apoptosis. These observations have led to our hypothesis that the activation of Beta1 integrin and small GTP-binding proteins, acting via common signaling pathways involving focal adhesion proteins, plays a protective role in beta-AR-stimulated apoptosis and myocardial remodeling. To test this hypothesis, we will use heterozygous knockout mice for Beta1 integrin and ARVM infection using adenoviruses. Aim 1 will determine in vivo the role of Beta1 integrin in beta-AR-stimulated apoptosis and myocardial remodeling using heterozygous Beta1 integrin knock-out mice. Aim 2 will define the mechanism by which beta1 integrin signaling provides protection against beta-AR-stimulated apoptosis. Aims 3 and 4 will define the role of small GTP-binding proteins (RhoA and RacI) in beta-AR-stimulated apoptosis and signaling. Aim 5 will determine the role of Gi proteins and identify the Gi subtypes involved in the activation of small GTP-binding proteins and FAK. These studies will advance our understanding of the signaling pathways activated by stimulation of beta-AR and Beta1 integrin, and their role in the regulation of cardiac myocyte apoptosis and myocardial remodeling.