Molecular Signals Against Beta-AR-Stimulated Apoptosis

描述（由申请人提供）：交感神经活动的增加是一种 心力衰竭患者的主要特征。心肌细胞丢失，由于 已经提出细胞凋亡在肿瘤的进展中起重要作用， 心衰我们已经证明，去甲肾上腺素，通过f3-肾上腺素能 受体（p3-AR），刺激成年大鼠心室肌细胞凋亡 （ARVM），β-AR和抑制性G蛋白（Gi）的刺激保护 抑制B1-AR刺激的细胞凋亡。我们还发现β-AR激活了 丝裂原活化蛋白激酶（MAPK）超家族（包括p38、JNKs 和ERKI/2），而Gi介导的p38活化可保护 β-AR刺激的细胞凋亡。其他人提供的证据表明G蛋白 偶联受体（GPCR）通过激活 小GTP结合蛋白（RhoA，racl和cdc 42），从而激活MAPK。 小GTP结合蛋白通过肌动蛋白激活粘着斑复合物蛋白 聚合和整联蛋白聚集。我们最近的初步数据显示 β 1整合素信号和RhoA的刺激可以保护ARVM免受 β-AR刺激的细胞凋亡。粘着斑激酶（FAK）是一种重要的 黏着斑复合物，在β-AR刺激和抑制 粘着斑复合物的另一种酶Src激酶增加 β-AR刺激的细胞凋亡。这些观察使我们假设， β 1整合素和小GTP结合蛋白的激活，通过共同的 涉及黏着斑蛋白的信号通路，起保护作用 β-AR刺激的细胞凋亡和心肌重塑。为了验证这一 假设，我们将使用β 1整合素和ARVM的杂合敲除小鼠 使用腺病毒感染。目的1将确定β 1在体内的作用， 整合素在β-AR刺激的细胞凋亡和心肌重塑中的作用 杂合β 1整联蛋白敲除小鼠。目标2将通过以下方式定义该机制： 其中β 1整合素信号传导提供针对β-AR刺激的 凋亡目的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传导中的作用。目标5将 确定Gi蛋白的作用，并确定Gi亚型参与 小GTP结合蛋白和FAK的活化。这些研究将进一步 我们对刺激β-AR激活的信号通路的理解 β 1整合素及其在心肌细胞凋亡调控中的作用 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.