Role of VCP in coronary ischemic injury

项目摘要 在美国，冠状动脉心脏病(CAD)是主要的死亡原因。尽管缺血前 预适应(IPC)已被公认为冠心病心脏保护的“金标准”方法 缺血性损伤；由于触发的要求，其在临床环境中的应用仍然困难 冠脉缺血再灌流发作。因此，理解IPC诱导的分子适应是 非常重要，并将有助于开发新的治疗方法。最近，我们发现Valosin- 含有蛋白(VCP)，一种与ATPase相关的蛋白，以前在心脏中没有特征，是一个关键 IPC诱导的心脏保护的介体。具体地说，我们发现VCP在IPC心脏上调， VCP过表达对体外培养心肌细胞应激诱导的细胞凋亡具有保护作用 在活体内显著减少冠状动脉缺血损伤的梗塞范围，与由 IPC。此外，我们发现VCP在心肌细胞中的表达导致心肌细胞内VCP的积聚和激活 线粒体诱导型一氧化氮合酶和线粒体蛋白的S亚硝化。我们 还发现VCP的表达导致雷帕霉素复合体2(MTORC2)靶标的激活，并 依赖mTORC2的信号转导。此外，我们已经确定了VCP的一个调节性N-结构域，它是必不可少的 用于VCP介导的细胞保护。总而言之，我们的数据可能发现了一个以前未被认识到的角色 VCP在心脏保护中的应用，提示VCP是一种潜在的治疗冠心病的新候选药物。 然而，尽管有这些令人兴奋的初步发现，VCP在保护脑血管疾病中的生理意义 冠状动脉缺血损伤还没有精确地建立起来，其潜在的分子机制是通过 哪种VCP介导mTOCR2激活，VCP/mTORC2信号导致iNOS线粒体 移位和功能在很大程度上是未知的。我们的中心假设是VCP是一种强有力的媒介 对冠状动脉缺血损伤的心脏保护作用；它通过激活mTORC2和 MTORC2介导的iNOS线粒体易位，导致线粒体功能的保存和 增强心肌对冠脉缺血损伤的耐受性，我们将通过一个 在两个具体目标下的一系列综合实验。在目标1下，我们将定义生理学 VCP在小鼠冠状动脉缺血损伤中的意义及治疗潜力。在目标2下，我们将 确定VCP促进mTORC2激活和iNOS线粒体的分子机制 易位与心肌细胞存活。我们预计这项研究将通过建立 VCP在冠脉缺血性损伤中的保护作用及更好的治疗研究开辟新途径 CAD。

Project Summary Coronary artery heart disease (CAD) is the leading cause of death in the United States. Although pre-ischemic preconditioning (IPC) has been accepted as the "gold standard" method of cardioprotection against coronary ischemic injury; its application remains difficult in the clinical setting because of the requirement of triggering episodes of coronary ischemia reperfusion. Thus, understanding the molecular adaptations induced by IPC is of paramount importance and will help developing novel therapy. Recently, we found that the valosin- containing protein (VCP), an ATPase-associated protein, previously uncharacterized in the heart, is a key mediator of IPC-induced cardiac protection. Specifically, we found that VCP is upregulated in the IPC hearts, and that overexpression of VCP protects cardiomyocytes from the stress-induced apoptosis in vitro and dramatically reduces the infarct size of coronary ischemic injury in vivo, as effective as those conferred by the IPC. Additionally, we found that VCP expression in cardiomyocytes leads to accumulation and activation of the inducible nitric oxide synthase (iNOS) in mitochondria and S-Nitrosylation (SNO) of mitochondrial proteins. We also found that VCP expression leads to activation of the target of rapamycin complex 2 (mTORC2) and mTORC2-dependent signaling. Furthermore, we have identified a regulatory N-domain of VCP that is essential for VCP-mediated cyto-protection. Collectively, our data may have discovered a previously unrecognized role of VCP in cardiac protection and suggests that VCP is a potential novel candidate for therapy of CAD. However, despite these exciting preliminary findings, the physiological significance of VCP in the protection of coronary ischemic injury has not been exquisitely established, and the underlying molecular mechanisms by which VCP mediates mTOCR2 activation and by which VCP/mTORC2 signaling leads to iNOS mitochondrial translocation and function have been largely unknown. Our central hypothesis is that VCP is a potent mediator of cardioprotection against coronary ischemic injury; it promotes cardiac survival by activating mTORC2 and mTORC2-mediated iNOS mitochondrial translocation, leading to preservation of mitochondrial function and enhancement of myocardial tolerance to coronary ischemic injury, We will test our central hypothesis by a comprehensive set of experiments under two specific aims. Under Aim 1 we will define the physiological significance and therapeutic potential of VCP in coronary ischemic injury in mice. Under Aim 2, we will determine the molecular mechanisms by which VCP promotes mTORC2 activation and iNOS mitochondrial translocation and cardiomyocyte survival. We expect that this study will advance the field by establishing the protective role of VCP in coronary ischemic injury and opening new avenues into research for better therapy of CAD.