Role of protein S-nitrosation in cardioprotection

描述（由申请人提供）：本提案的目的是阐明S-亚硝化（SNO）对缺血-再灌注损伤的心脏保护机制。S-亚硝化是最近描述的蛋白质修饰，其中一氧化氮部分共价连接到半胱氨酸残基的巯基，导致S-亚硝基硫醇的形成。SNO是一种可逆的修饰，已被证明可以改变靶蛋白的活性。此外，据报道，SNO可保护硫醇基团免受氧化损伤。心肌细胞内源性产生一氧化氮的潜在来源包括一氧化氮合酶和非酶促方法。冠状动脉的短暂闭塞通常导致心脏缺血-再灌注损伤。这种类型的损伤可导致心脏功能障碍，最初是可逆的（心肌顿抑），后来是不可逆的（梗死），以及室性心律失常。然而，心脏保护作用是由缺血预处理引起的，缺血预处理是一种由几次短暂的缺血发作发展而来的心脏保护机制。据报道，这种心脏保护措施可增加心肌细胞中的S-亚硝化形成。此外，来自女性的心脏表现出内源性心脏保护，这已被证明是NOS依赖性的。然而，研究尚未完全表征SNO形成所必需的信号通路或SNO形成发挥心脏保护作用的机制。因此，需要进一步的研究，以检查的作用，S-亚硝化在心脏保护。S-亚硝化的作用将在本提案的具体目标中得到解决，具体如下：1）确定心脏保护中S-亚硝化形成所必需的特定信号传导途径，2）确定心脏保护期间SNO的特定半胱氨酸残基，3）确定S-亚硝化是否通过保护关键巯基免受氧化损伤而发挥心脏保护作用。本提案的总体假设如下：1）。SNO的形成和心脏保护作用是在激活特定的信号传导途径后启动的，2.）SNO发生在关键靶蛋白上的特定半胱氨酸残基处，和3.）SNO通过阻断氧化损伤提供心脏保护。公共卫生相关性：拟议研究的具体目标将确定S-亚硝化在心脏保护中的作用，并解决S-亚硝化用于保护缺血再灌注损伤的机制。这些结果也将有助于澄清文献中与一氧化氮合酶在心脏保护中的作用有关的不一致之处。此外，这些结果可以通过识别用于治疗干预的新靶点来改善人类心脏病患者的治疗。

DESCRIPTION (provided by applicant): The purpose of this proposal is to elucidate the mechanism whereby S-nitrosation (SNO) confers cardioprotection from ischemia-reperfusion injury. S-nitrosation is a recently described protein modification in which a nitric oxide moiety is covalently attached to a thiol group of a cysteine residue, leading to the formation of S-nitrosothiols. SNO is a reversible modification that has been shown to modify the activity of target proteins. Additionally, SNO has been reported to protect thiol groups from oxidative damage. Potential sources for the endogenous production of nitric oxide in cardiac myocytes include nitric oxide synthase and non-enzymatic means. Brief occlusion of a coronary artery generally results in cardiac ischemia-reperfusion injury. This type of injury can lead to cardiac dysfunction, which is initially reversible (myocardial stunning) and later irreversible (infarction), and ventricular arrhythmias. However, cardioprotective effects result from ischemic preconditioning, a protective mechanism of the heart that develops from several brief episodes of ischemia. This cardioprotective measure has been reported to increase S-nitrosation formation in the cardiac myocyte. Furthermore, hearts from females exhibit endogenous cardioprotection, which has been shown to be NOS-dependent. However, studies have yet to fully characterize the signaling pathways necessary for SNO formation or the mechanism(s) through which SNO formation exerts cardioprotection. Therefore, further studies are needed in order to examine the role of S-nitrosation in cardioprotection. The role of S-nitrosation will be addressed in the specific aims of this proposal and are as follows: 1) determine the specific signaling pathways that are necessary for S-nitrosation formation in cardioprotection, 2) identify the specific cysteine residues that are SNO during cardioprotection, and 3) determine if S-nitrosation exerts cardioprotective effects by shielding critical thiol groups from oxidative damage. The overall hypotheses of this proposal are as follows: 1.) SNO formation and cardioprotection is initiated upon activation of specific signaling pathways, 2.) SNO occurs at specific cysteine residues on key target proteins, and 3.) SNO provides cardioprotection by blocking against oxidative damage. PUBLIC HEALTH RELEVANCE: The specific aims of the proposed study will determine the role of S-nitrosation in cardioprotection and resolve the mechanism through which S- nitrosation serves to protect against ischemia-reperfusion injury. These results will also help to clarify inconsisties in the literature that relate to the role of nitric oxide synthase in cardioprotection. Additionally, these results may allow for improvements in the treatment of human cardiac patients by identifying novel targets for therapeutic intervention.