Extracellular redox biology links to metabolic and mitochondrial dysfunction in pulmonary hypertension

项目总结/摘要 尽管有新的治疗方法，肺动脉高压（PH）代表了一种进行性的，高度病态的， 往往是致命的。最近的研究表明，代谢紊乱，如糖酵解开关，活性氧 线粒体功能障碍在PH的发病机制中起关键作用。 主要由超氧化物（SOD）家族调节的体内平衡与PH相关。 细胞外超氧化物歧化酶（EC-SOD）是血管系统中最常见的SOD同工型， 先前在小鼠模型中与PH相关。在人类中，R213 G EC-SOD SNP导致 EC-SOD的基质结合亲和力降低，导致血管浓度降低，但血浆水平升高， 正常活动。在小鼠中，这种SNP与基线时较高的右心室压力相关， 缺氧会恶化有趣的是，这些相同的小鼠在Sugen缺氧模型中受到PH的保护。 我们假设EC-SOD的R213 G变体由于其结合亲和力降低而重新分布， 不同的影响取决于模型的PH值，这种影响将是由于不同的模型依赖 内皮细胞（PAEC）与平滑肌细胞中AMPK活化和线粒体功能障碍 （PASMC）。初步数据表明，在基线时，具有R213 G EC-SOD变体的小鼠具有 肺和右心室（RV）脂肪酸氧化和电子传递链活性的显著差异。 为了测试PH中血管EC-SOD损失的影响，将具有R213 G EC-SOD SNP的小鼠暴露于 慢性缺氧或Sugen-缺氧发展为肺动脉高压，通过有创血流动力学证实 和组织学测量（目标1）。线粒体呼吸和ROS产生将通过高- 分别在全肺和RV中进行分辨率呼吸测量和电子顺磁共振 匀浆以及人肺动脉内皮和平滑肌细胞（Aim 2）。

PROJECT SUMMARY/ABSTRACT Despite novel treatments, pulmonary hypertension (PH) represents a progressive, highly morbid, and often fatal condition. Recent studies suggest that metabolic derangements such as the glycolytic switch, ROS production, and mitochondrial dysfunction play a key role in the pathogenesis of PH. Disruptions of ROS homeostasis, primarily regulated by the superoxide (SOD) family, have been associated with PH. Extracellular superoxide dismutase (EC-SOD) is the most prevalent isoform of SOD in the vasculature and has been previously associated with PH in mouse models. In humans, the R213G EC-SOD SNP leads to a reduced matrix binding affinity of EC-SOD, leading to low vascular concentration but higher plasma levels and normal activity. In mice, this SNP has been associated with higher right ventricular pressures at baseline that worsen with hypoxia. Interestingly, these same mice are protected against PH in the Sugen-hypoxia model. We hypothesize that the redistribution of R213G variant of EC-SOD due to its reduced binding affinity will have discrepant effects depending on the model of PH and this effect will be due to distinct model-dependent activation of AMPK and mitochondrial dysfunction in endothelial cells (PAEC) vs. smooth muscle cells (PASMC). Preliminary data demonstrated that at baseline, mice with the R213G EC-SOD variant have significant differences in lung and right ventricular (RV) fatty acid oxidation and electron transport chain activity. To test the effects of loss of vascular EC-SOD in PH, mice with the R213G EC-SOD SNP will be exposed to chronic hypoxia or Sugen-hypoxia to develop pulmonary hypertension, confirmed via invasive hemodynamic and histologic measures (Aim 1). Mitochondrial respiration and ROS production will be measured by high- resolution respirometry and electron paramagnetic resonance, respectively, in whole lung and RV homogenates as well as human pulmonary artery endothelial and smooth muscle cells (Aim 2).