Regulation Of Ischemic Preconditioning By Compartmentalized Signal Transduction

描述（由申请人提供）：心脏病是美国发病率和死亡率的主要原因。了解这种疾病的原因并开发治疗方法是生物医学研究的重要目标。尽管缺氧会导致心脏组织损伤，但通过短暂的缺血-再灌注可以保护心肌。尽管这种现象涉及磷脂酰肌醇-3 '激酶途径（PI 3 K）的活化，但在这种反应期间PI 3 K的分子调节尚未被很好地定义。在这个提议中，我们希望确定interstin（ITSN）支架蛋白通过调节PI 3 K家族在调节心脏组织对缺血再灌注（IR）损伤的反应中的作用。我们已经确定PI 3 Ks作为ITSN结合蛋白，并将确定ITSN在心肌细胞和新型小鼠模型（包括心脏特异性ITSN转基因小鼠（MHC-ITSN）和ITSN敲除小鼠）中调节PI 3 Ks的作用。我们提出以下四个具体目标来确定ITSN调节心肌缺血损伤保护作用的分子机制：（1）确定ITSN在调节心肌细胞中PI 3 K活化中的作用;（2）确定ITSN调节PI 3 K活化的机制;（3）确定ITSN-PI 3 K发出的下游信号;以及（4）确定ITSN在体内介导响应于IR损伤的心脏保护中的重要性。针对特定目的1-3拟定的实验将定义ITSN对各种PI 3 K家族成员的分子调节，以响应体外模型中G蛋白偶联受体和受体酪氨酸激酶活化以及该活化产生的下游信号。在具体目标4中，这些结果将应用于我们创建的新型小鼠模型的研究。MHC-ITSN小鼠将解决ITSN过表达对IR损伤的心脏保护的后果，而敲除小鼠将解决ITSN损失对IR损伤的响应的后果。这些数据将为ITSN在心脏组织中调节PI 3 K蛋白家族提供新的分子见解，并将定义这种调节在心脏保护和心脏功能中的重要性。公共卫生相关性：心肌梗死对美国医疗保健系统造成重大负担。我们提出的研究将确定新的分子途径参与保护心脏免受缺血性损伤。鉴于这些途径也在包括大脑在内的许多组织中共享，这些研究也可能为限制中风的有害影响提供新的见解。

DESCRIPTION (provided by applicant): Heart disease represents a leading cause of morbidity and mortality in the US. Understanding the causes and developing treatments for this disease is an important goal of biomedical research. Although oxygen deprivation results in damage to cardiac tissue, it is possible to protect the myocardium by brief periods of ischemia-reperfusion. Although this phenomenon involves activation of the phosphatidylinositol-3' kinase pathway (PI3K), the molecular regulation of PI3Ks during this response has not been well defined. In this proposal, we wish to determine the role of the intersectin (ITSN) scaffold protein in regulating the response of cardiac tissue to ischemia-reperfusion (IR) injury through regulation of the PI3K family. We have identified PI3Ks as ITSN-binding proteins and will determine the role of ITSN in regulating PI3Ks both in myocardial cells and in novel mouse models including a cardiac-specific ITSN transgenic mouse (MHC-ITSN) and an ITSN knockout mouse. We propose the following four specific aims to define the molecular mechanisms by which ITSN regulates cardioprotection from ischemic injury: (1) determine the role of ITSN in regulating PI3K activation in cardiomyocytes; (2) determine the mechanism by which ITSN regulates PI3K activation; (3) determine the downstream signals emanating from ITSN-PI3K; and (4) determine the importance of ITSN in mediating cardioprotection in response to IR injury in vivo. The experiments proposed for Specific Aims 1-3 will define the molecular regulation of the various PI3K family members by ITSN in response to G-protein coupled receptor and receptor tyrosine kinase activation and the downstream signals resulting from this activation in in vitro models. In Specific Aim 4, these results will be applied to the study of the novel mouse models created by us. The MHC-ITSN mice will address the consequence of ITSN overexpression on cardioprotection from IR injury whereas the knockout mice will address the consequences of ITSN loss on the response to IR injury. These data will provide novel molecular insight into the regulation of the PI3K family of proteins by ITSN in cardiac tissue and will define the importance of this regulation in cardioprotection and cardiac function. PUBLIC HEALTH RELEVANCE: Myocardial infarction results in a significant burden to the US healthcare system. Our proposed studies will define novel molecular pathways involved in protecting the heart from ischemic injury. Given that these pathways are also shared among many tissues including the brain, these studies may also provide novel insights into limiting the harmful effects from stroke.