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

项目摘要/摘要 尽管有新的治疗方法，但肺动脉高压(PH)是一种进行性的、高度病态的和 通常是致命的情况。最近的研究表明，代谢紊乱，如糖酵解开关，ROS 线粒体功能障碍在PH的发病机制中起着关键作用。ROS中断 动态平衡主要由超氧化物歧化酶(SOD)家族调节，与PH有关。 细胞外超氧化物歧化酶(EC-SOD)是血管系统中最常见的超氧化物歧化酶亚型，具有 以前在小鼠模型中与PH有关。在人类中，R213G EC-SOD SNP导致 EC-SOD的基质结合亲和力降低，导致血管浓度低，但血浆和 正常活动。在小鼠中，这种SNP与基线时较高的右室压有关 在缺氧的情况下恶化。有趣的是，在SUGEN缺氧模型中，这些小鼠对PH有保护作用。 我们推测，由于结合亲和力降低，EC-SOD的R213G变体的重新分布将具有 不同的PH模型会产生不同的影响，这种影响是由于不同的模型依赖造成的 血管内皮细胞与血管内皮细胞AMPK的激活和线粒体功能障碍 (PASMC)。初步数据显示，在基线水平，携带R213G EC-SOD变体的小鼠 肺和右室(RV)脂肪酸氧化和电子传输链活性有显著差异。 为了测试血管EC-SOD在PH中丢失的影响，将携带R213G EC-SOD SNP的小鼠暴露于 慢性低氧或继发性低氧可发展为肺动脉高压，经有创血流动力学证实 组织学指标(目标1)。线粒体呼吸和ROS的产生将通过高密度的 全肺和右室分别进行分辨率呼吸测量和电子顺磁共振检查 匀浆以及人的肺动脉内皮细胞和平滑肌细胞(目标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).