Alpha1-Adrenoceptor Subtype Signaling in Preconditioning

描述（由申请人提供）：心肌预适应（PC）保护心脏免受缺血性心脏病和缺血再灌注损伤的影响。缺血时释放的儿茶酚胺通过激活心脏中的α -肾上腺素受体（AR）诱导心肌PC。两种α - 1- ar亚型在心脏中表达。最近，在alpha1-AR亚型敲除（KO）小鼠中，发现每种alpha1-AR亚型激活不同的信号通路。该项目的主要目标是确定儿茶酚胺诱导的PC的亚型，诱导PC的机制，以及最终是否可以利用治疗方法来利用亚型特异性信号来促进心脏健康。在功能丧失研究中，将使用α 1- ar亚型KO小鼠来确定负责儿茶酚胺诱导的早期和晚期PC的α 1- ar亚型。我们将采用小鼠体内模型研究α - 1- ar和缺血诱导的PC对梗死面积的影响。采用体外小鼠Langendorf心脏模型，研究α - 1- ar和缺血诱导的PC对心肌昏迷的影响。亚型特异性信号级联研究将重点关注预处理过程中通过PI3K/AKT、活性氧、蛋白激酶C、丝裂原活化蛋白激酶和酪氨酸激酶激活的抗凋亡信号。在免疫沉淀实验中，将使用标记的alpha1A和alpha1B亚型来研究在每个亚型上形成的可以解释亚型信号传导差异的信号复合物。晚期PC需要基因转录。我们已经确定了几个可能参与晚期PC的候选基因。基因表达的调控以及这些基因产物在PC中的作用将被研究。在许多临床应用中，心脏在长期缺血性心脏病或缺血再灌注损伤中暴露或处于危险中的能力将是一个重要的贡献。过度表达和增强与PC相关的alpha1-AR亚型特异性信号的益处将通过基因治疗方法进行测试。该亚型将在心脏急性表达使用腺病毒载体。

DESCRIPTION (provided by applicant): Myocardial preconditioning (PC) protects the heart from the consequences of ischemic heart disease and ischemia - reperfusion injury. Catecholamines released during ischemia induce myocardial PC by activating alpha1-adrenoceptors(AR) in the heart. Two alpha1-AR subtypes are expressed in the heart. Recently, in alpha1-AR subtype knockout (KO) mice, each alpha1-AR subtype was found to activate different:signaling pathways. The broad objective of this project is to define the subtype(s) that are responsible for catecholamine induced PC, the mechanisms by which PC is induced, and ultimately whether therapeutics can be utilized to capitalize on subtype specific signaling to benefit cardiac health. The alpha1-AR subtype(s) responsible for catecholamine induced early and late PC will be determined using alpha1-AR subtype KO mice in loss of function studies. An in vivo mouse model of ischemic PC will be used to study the effect of alpha1-AR- and ischemia- induced PC on infarct size. An in vitro mouse Langendorf heart model will be used to study the effect of alpha1-AR- and ischemia- induced PC on myocardial stunning. Subtype specific signaling cascade studies will focus on antiapoptotic signaling via PI3K/AKT, reactive oxygen species, protein kinase C, mitogen activated protein kinases, and tyrosine kinase activation during preconditioning protocols. Signaling complexes formed at each subtype that can account for differences in subtype signaling will be studied using tagged alpha1A and alpha1B subtypes in immunoprecipitation experiments. Late PC requires gene transcription. We have identified several candidate genes that may participate in late PC. The regulation of gene expression and how these gene products contribute to PC will be studied. The ability to precondition the heart for prolonged periods would be an important contribution to many clinical applications where:the heart is exposed to or at risk during prolonged ischemic heart disease or with ischemia - reperfusion injury. The benefits of overexpressing and enhancing alpha1-AR subtype-specific signaling responsible for PC will be tested using a gene therapy approach. The subtype will be expressed in the heart acutely using an adenovirus vector.