Bmx Tyrosine Kinase Signaling in Cardiac Protection

Bmx 酪氨酸激酶信号传导在心脏保护中的作用

• 批准号: 7581041
• 负责人: Sarah Franklin
• 金额: $ 4.72万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-02-29 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7581041
• 关键词: Biochemistry; Cardiac; Cardiac Myocytes; Cell Death; Cell Survival; Cells; Confocal Microscopy; Family; Goals; Heart; Heart Block; Hindlimb; Injury; Ischemia; Ischemic Preconditioning; Knock-out; Knockout Mice; Link; Maps; Measures; Methods; Mitochondria; Mitochondrial Proteins; Molecular; Mus; Myocardial Ischemia; Nitric Oxide; Nitric Oxide Donors; Organelles; Permeability; Pharmaceutical Preparations; Phenotype; Phosphorylation Site; Physiology; Prevention; Protein Tyrosine Kinase; Proteins; Proteomics; Receptor Protein-Tyrosine Kinases; Reperfusion Injury; Reporting; Role; Signal Transduction; Skeletal Muscle; Testing; Tissues; Tyrosine Kinase Inhibitor; base; insight; mitochondrial dysfunction; myocardial infarct sizing; prevent; protein expression; response

DESCRIPTION (provided by applicant): Ischemic preconditioning is the most potent and consistently reproducible method of preventing heart tissue from undergoing irreversible ischemic damage. Induction of this phenomenon can be recapitulated in lieu of ischemia by drugs such as nitric oxide (NO) donors, which significantly reduce myocardial infarct size. Cardiac cell death in ischemia/reperfusion injury is known to centrally involve malfunction of the mitochondria (mitochondrial permeability transition [MPT]), and protection thus requires prevention of MPT. Although the signaling mechanisms which prevent mitochondrial dysfunction in cardiac protection are unknown, tyrosine kinase signaling has been implicated based on the ability of tyrosine kinase inhibitors to block cardiac protection. The non-receptor tyrosine kinase, Bmx, which has an established role in cytoprotective signaling in non-cardiac cells, was recently identified in cardiac tissue. This protein has been shown to be activated by PI3-K and Src in non-cardiac cells, although how it is activated in the cardiomyocyte is completely unknown. Our preliminary results have shown that the hearts of Bmx knockout (KO) mice cannot be protected with NO donors, thereby implicating Bmx as a previously unrecognized necessary component of protective signaling. Because of these observations, we hypothesize that Bmx signaling is activated in cardiomyocytes in response to cardiac protection and promotes cell survival, at least in part, by regulating mitochondrial function. We propose two Aims that combine biochemistry, proteomic analysis, confocal microscopy and cell/organelle physiology to test this hypothesis: First, we will characterize Bmx activation in mouse cardiomyocytes during NO donor induced protection by determining the role of PI3-K and Src, identifying activators of Bmx and mapping the phosphorylation sites necessary for cardiac protective signaling. Second, we will evaluate the role of Bmx signaling in NO donor induced cardiac protection by measuring mitochondrial function in Bmx KO mice, identifying Bmx associated proteins at this organelle, and determining Bmx-dependent changes in mitochondrial protein expression. Determining Bmx signaling mechanisms will establish the first insights into a newly discovered family of tyrosine kinases in the heart and allow a better understanding of the protective phenotype with the goal of developing molecular approaches to treat ischemic heart disease.

描述（由申请人提供）：缺血预处理是防止心脏组织遭受不可逆缺血损伤的最有效且一致可重复的方法。这种现象可以通过一氧化氮（NO）供体等药物来代替缺血，从而显着减少心肌梗塞的面积。众所周知，缺血/再灌注损伤中的心肌细胞死亡主要涉及线粒体功能障碍（线粒体通透性转变 [MPT]），因此保护需要预防 MPT。尽管在心脏保护中防止线粒体功能障碍的信号传导机制尚不清楚，但基于酪氨酸激酶抑制剂阻断心脏保护的能力，已经涉及酪氨酸激酶信号传导。非受体酪氨酸激酶 Bmx 最近在心脏组织中被发现，它在非心肌细胞的细胞保护信号传导中发挥着重要作用。该蛋白已被证明在非心肌细胞中被 PI3-K 和 Src 激活，尽管它在心肌细胞中的激活方式尚不清楚。我们的初步结果表明，Bmx 敲除 (KO) 小鼠的心脏不能受到 NO 供体的保护，从而暗示 Bmx 是以前未被识别的保护性信号传导的必要组成部分。由于这些观察结果，我们假设 Bmx 信号在心肌细胞中被激活，以响应心脏保护，并至少部分通过调节线粒体功能来促进细胞存活。我们提出了两个结合生物化学、蛋白质组分析、共聚焦显微镜和细胞/细胞器生理学的目标来检验这一假设：首先，我们将通过确定 PI3-K 和 Src 的作用来表征 NO 供体诱导的保护期间小鼠心肌细胞中的 Bmx 激活，识别Bmx 激活剂并绘制心脏保护信号所需的磷酸化位点。其次，我们将通过测量 Bmx KO 小鼠的线粒体功能、鉴定该细胞器中的 Bmx 相关蛋白以及确定线粒体蛋白表达中 Bmx 依赖性变化来评估 Bmx 信号传导在 NO 供体诱导的心脏保护中的作用。确定 Bmx 信号传导机制将首次深入了解心脏中新发现的酪氨酸激酶家族，并更好地了解保护性表型，目标是开发治疗缺血性心脏病的分子方法。