Nitric Oxide and sex differences in cardiac repair

项目概述：该项目将对心血管疾病（CVD）的治疗产生重大影响， 是全球男性和女性死亡的主要原因。绝经前妇女不易患心脏病 这种保护作用在绝经后就丧失了。新出现的数据表明， 一氧化氮（NO）和活性氧（ROS）之间的亚硝基氧化还原平衡，在 这种与性有关的心脏保护作用。阐明这些性别差异背后的机制对于以下方面至关重要： 开发有效的治疗方法。半胱氨酸巯基的S-亚硝基化（S-NO）是一条重要的信号通路 NO通过其发挥其广泛的调节作用。人们日益认识到， NO的信号传导命运最终取决于亚硝基-氧化还原平衡的细胞内状态; 过量产生的活性氧会破坏生理性S-NO，而CVD可能反映了蛋白质S-调节异常 号我们已经表明，亚硝基/氧化还原平衡是CV健康和疾病的重要调节因子。女性 小鼠心脏中的S-亚硝基化蛋白质增加了65%，并在生理上调节这种升高的S-亚硝基化蛋白质水平。 NO与S-亚硝基谷胱甘肽（GSNO）还原酶（GSNOR）的活性增加，GSNOR是一种促进 蛋白质去亚硝基化我们之前的研究表明，缺乏S-亚硝基谷胱甘肽（GSNO）还原酶的雄性小鼠， 一种通过促进蛋白质去亚硝基化来控制S-NO水平的酶（GSNOR− <$−小鼠）表现出改善的 心肌梗死（MI）后的存活率。此外，怀孕的GSNOR−/−小鼠表现出所有的临床表现， 妊娠期主要并发症先兆子痫（PE）的特征，包括母体高血压、蛋白尿 以及异常的CV适应。GSNOR−/−女性的不良结果可能是由于氧化应激，因为我们的研究表明， 初步数据显示，GSNOR−/−雌性的心肌细胞（CM）产生的ROS比 对照雌性和GSNOR−/−雄性的CM。因此，S-NO增加的状态可导致 不利的环境，如果伴随着氧化应激，我们已经发现了性相关的关系 心脏病理与细胞内亚硝基氧化还原失衡之间的关系，这取决于NO和ROS 生产和S-NO的形成和脱亚硝基化。我们的中心假设是，GSNOR的缺失 在正常ROS水平的设定下产生性别特异性的抗氧化剂环境（即，男性），但其中之一 当ROS升高时的亚硝化/氧化应激（即，女性）。我们的建议旨在确定 这一二分法背后的机制。具体目的是检验以下假设：1） 亚硝基-氧化还原蛋白信号传导决定对CV应激的性别特异性反应; 2） 妊娠期间心肌细胞的变化是妊娠相关CVD的基础; 3）GSNOR产生性别特异性 改变CV功能的蛋白质S-亚硝基化的变化。这些目标将提供新的见解 亚硝基氧化还原调节心脏功能的生理和病理生理应激反应， 对男性和女性心血管疾病的治疗具有重要意义。

Project Summary: This program will have a major impact in the treatment of cardiovascular disease (CVD), the leading cause of death in men and women globally. Premenopausal women are less susceptible to heart disease than men, and this protection is lost after menopause. Emerging data suggest that the interplay between nitric oxide (NO) and reactive oxygen species (ROS), the nitroso-redox balance, plays a critical role in this sex-related cardioprotection. Elucidating the mechanisms underlying these gender differences is critical for development of effective therapies. S-nitrosylation (S-NO) of cysteine thiols is a major signaling pathway through which NO exerts its broad regulatory actions. It is increasingly appreciated that the underlying signaling fate of NO ultimately depends upon an intracellular state of nitroso-redox balance; such that excessive production of ROS can disrupt physiological S-NO and that CVD may reflect dysregulated protein S- NO. We have shown that the nitroso/redox balance is an important regulator of CV health and disease. Female mice have 65% more S-nitrosylated proteins in the heart6 and physiologically regulate this elevated level of S- NO with increased activity of S-nitrosoglutathione (GSNO) reductase (GSNOR), an enzyme that promotes protein denitrosylation. We previously showed that male mice lacking S-nitrosoglutathione (GSNO) reductase, an enzyme that governs S-NO levels by promoting protein denitrosylation (GSNOR−⁄− mice) exhibit improved survival after myocardial infarction (MI). Furthermore, pregnant GSNOR−/− mice exhibit all of the clinical features of a major complication in pregnancy, preeclampsia (PE), including maternal hypertension, proteinuria and abnormal CV adaptation. Poor outcome in the GSNOR−/− females may be due to oxidative stress, as our preliminary data shows that cardiomyocytes (CMs) from GSNOR−/− females generate more ROS as compared to CMs from control females and GSNOR−/− males. Therefore, the state of increased S-NO can lead to an adverse milieu if accompanied by oxidative stress and we have uncovered a sex-associated relationship between cardiac pathology and intra-cellular nitroso-redox imbalance, which is dependent on NO and ROS production and S-NO formation and denitrosylation. Our central hypothesis is that the absence of GSNOR produces a sex-specific, antioxidant milieu in the setting of normal ROS levels (i.e., males) but one of nitrosative/oxidative stress when ROS is elevated (i.e., females). Our proposal aims to identify the fundamental mechanisms underlying this dichotomy. The specific aims are to test the hypotheses that 1) differences in nitroso-redox protein signaling determine sex-specific responses to CV stress; 2) nitroso-redox imbalance in cadiomyocytes during pregnancy underlies pregnancy-related CVD; and 3) GSNOR produces sex-specific changes in the S-nitrosylation of proteins that alter CV function. Together these aims will provide novel insights into nitroso-redox regulation of cardiac function in response to physiologic and pathophysiologic stressors and have significant implications for the treatment of CVD in men and women.