AKIP1 regulation of PKA and NF-KB in the heart

心血管疾病是美国发病率和死亡率的主要原因， 冠状动脉疾病导致的死亡率。缺血预处理是一种内源性保护机制， 用于挽救缺血心肌的机制，描述了近25年前，几乎没有 没有临床翻译。心脏中的保护机制利用许多途径;然而， 可能整合这种保护性反应的控制点需要进一步表征。核因子-κ B (NF-κB）和蛋白激酶A（PKA）是心脏基因转录的关键调节因子， 在细胞死亡和存活中扮演着相互矛盾的角色。NF-κB和PKA的激活对心脏有保护作用;然而， NF-κB和PKA在缺血或氧化应激的情况下也促进心脏细胞死亡。的答案 为什么这两个重要的基因转录和心脏生理调节器产生这样的问题， 依赖于施加到系统的压力的二分反应可以提供关于保护性的见解。 心脏中的信号被整合。我们的实验室发现了一种新的支架蛋白，叫做A- 激酶相互作用蛋白1（AKIP 1），在心脏中以低水平表达，由应激诱导。我们 初步数据显示AKIP 1结合并调节PKA催化亚基的核定位， 增加核PKA活性。初步数据进一步显示AKIP 1与NF-κB相互作用并增强NF-κB的表达。 以PKA磷酸化依赖的方式进行核定位，其中AKIP 1与PKA结合的破坏 增强核NF-κB。其他人已经表明AKIP 1的翻译后修饰（例如，neddylation） 募集组蛋白去乙酰化酶（SIRT 1）以抑制NF-κ B介导的转录。这些数据表明AKIP 1 调节NF-κB和PKA的定位和转录激活。我们假设AKIP 1可能是 组装PKA和NF-κB信号传导复合物以改变 心脏在基础状态和应激状态下的生理反应。了解动态和 PKA和NF-κB与AKIP 1相互作用的生理学意义可能提供一种新的治疗控制 限制与缺血性应激相关的心脏损伤的点。以下目标将检验这一假设。目的 1：确定缺氧和氧化应激如何改变AKIP 1与NF-κB和PKA的相互作用，以及如何破坏AKIP 1与NF-κB和PKA的相互作用。 这种相互作用改变了心肌细胞的应激适应。目标2：确定AKIP 1如何调节全球 对PKA和NF-κB的转运和转录活性有特异性影响。目标3：确定 AKIP 1与PKA和NF-κB相互作用对缺血再灌注损伤保护作用

Cardiovascular disease is the leading cause of morbidity and mortality in the United States with >50% of mortality attributed to coronary artery disease. Though ischemic preconditioning, an endogenous protective mechanism used to salvage ischemic myocardium, was described nearly 25 years ago, there has been little to no clinical translation. Protective mechanisms in the heart utilize a number of pathways; however, unifying control points that might integrate this protective response need further characterization. Nuclear factor-kappa B (NF-κB) and protein kinase A (PKA) are critical regulators of gene transcription in the heart and have contradictory roles in cell death and survival. Activation of NF-κB and PKA is protective to the heart; however, NF-κB and PKA also promote cardiac cell death in the setting of ischemia or oxidant stress. The answer to the question as to why these two important regulators of gene transcription and cardiac physiology produce such a dichotomous response dependent on the stress applied to the system may provide insights into how protective signaling in the heart is integrated. Our laboratories have discovered a novel scaffolding protein known as A- kinase interacting protein 1 (AKIP1) that is expressed at low levels in the heart and is induced by stress. Our preliminary data show that AKIP1 binds to and regulates nuclear localization of PKA catalytic subunit and increases nuclear PKA activity. Preliminary data further show that AKIP1 interacts with and enhances NF-κB nuclear localization in a PKA phosphorylation dependent manner where disruption of AKIP1 binding to PKA enhances nuclear NF-κB. Others have shown that post-translational modification of AKIP1 (e.g., neddylation) recruits the histone deacetylase (SIRT1) to inhibit NF-κB-mediated transcription. Such data suggest that AKIP1 regulates both localization and transcriptional activation of NF-κB and PKA. We hypothesize that AKIP1 may be a key molecular regulator/scaffold that assembles PKA and NF-κB signaling complexes to alter the physiological response of the heart in the basal and stressed state. Understanding the dynamics and physiologic implications of the interaction of PKA and NF-κB with AKIP1 may provide a novel therapeutic control point for limiting cardiac injury associated with ischemic stress. The following aims will test this hypothesis. Aim 1: Determine how hypoxic and oxidant stress alter AKIP1 interactions with NF-κB and PKA and how disruption of this interaction alters stress adaptation in cardiac myocytes. Aim 2: Determine how AKIP1 regulates global and specific effects on the translocation and transcriptional activity of PKA and NF-κB. Aim 3: Determine the impact of AKIP1 interaction with PKA and NF-κB on protection from ischemia-reperfusion injury.