Prostanoids and Hypoxic Neonatal Pulmonary Hypertension

描述（由申请人提供）：预防新生儿肺动脉高压发生或进展的治疗很少受到关注，并且主要针对一氧化氮途径。我们的研究结果表明，前列腺素和NADPH氧化酶信号通路之间的相互作用在慢性缺氧诱导的新生儿肺动脉高压的早期发展中起着关键作用。我们的总体假设是，在缺氧暴露3天内，前列腺素和NADPH氧化酶信号会发生中断，从而介导平滑肌细胞（SMC）活性氧（ROS）产生和电压门控K+ (Kv)通道功能的变化。这些变化创造了一个前馈过程，自我延续血管功能障碍，并在缺氧延长至10天时被放大。具体假设是：慢性缺氧(1)激活前列腺素和NADPH氧化酶途径，导致肺阻力动脉（PRAs）中收缩前列腺素生成和ROS生成升高，进而(2)损害SMC Kv通道功能，导致SMC膜（Em）去极化和胞质钙浓度升高。特异性目的1将确定3天或10天缺氧对(a)前列腺素和NADPH氧化酶信号通路对ROS产生和异常PRA反应的相对贡献（使用管状PRA， lucigenin衍生的化学发光，氧化敏感荧光染料和培养SMC技术）和(b) NADPH氧化酶和超氧化物歧化酶的数量（免疫印迹），活性（酶测定）和主要细胞位置（免疫组织化学）的影响。主要发现将通过体内研究进行验证。特异性目标2将评估3天或10天缺氧对(a) Kv通道对血管张力（管状动脉）的贡献(b) SMC Em（微电极）(c) SMC Ca2+（荧光）和(d) Kv通道数量（免疫印迹）的影响。我们的研究结果将为设计干预慢性缺氧相关婴儿肺动脉高压发展的治疗方法提供新的信息。相关性：肺动脉高压是一种公认的婴儿肺部和心脏疾病的并发症。目前，几乎没有治疗这些婴儿的好方法。这个项目的目标是帮助我们理解为什么婴儿会患上肺动脉高压，确定疾病发展过程中肺血管发生了什么，并开发这种疾病的治疗方法。

DESCRIPTION (provided by applicant): Therapies for preventing the onset or progression of neonatal pulmonary hypertension have received little attention and have largely targeted the nitric oxide pathway. Our findings indicate that an interplay between the prostanoid and NADPH oxidase signaling pathways plays a key role early in the development of chronic hypoxia-induced neonatal pulmonary hypertension. Our overall hypothesis is that within 3 days exposure to hypoxia, disruptions in prostanoid and NADPH oxidase signaling occur which mediate changes in smooth muscle cell (SMC) reactive oxygen species (ROS) production and voltage-gated K+ (Kv) channel function. These changes create a feed-forward process that self-perpetuates vascular dysfunction and is amplified when hypoxia is extended to 10 days. The specific hypotheses are: chronic hypoxia (1) activates prostanoid and NADPH oxidase pathways leading to elevated constrictor prostanoid production and ROS generation in SMCs of pulmonary resistance arteries (PRAs) which in turn (2) impairs SMC Kv channel function, causing SMC membrane (Em) depolarization and elevated cytosolic calcium concentration. Specific Aim 1 will determine the effect of 3 or 10 days hypoxia on (a) relative contributions of prostanoid and NADPH oxidase signaling pathways to ROS production and aberrant PRA responses (using cannulated PRA, lucigenin- derived chemiluminescence, oxidant-sensitive fluorescent dye, and cultured SMC techniques) and (b) amounts (immunoblot), activity (enzyme assays) and predominant cellular locations (immunohistochemistry) of NADPH oxidase and superoxide dismutases. Key findings will be validated with in vivo studies. Specific Aim 2 will evaluate the effect of 3 or 10 days hypoxia on (a) contribution of Kv channels to vascular tone (cannulated arteries) (b) SMC Em (microelectrode) (c) SMC Ca2+ (fluorescence) and (d) Kv channel amounts (immunoblot). Our findings will provide new information needed to devise therapies to intervene with the development of pulmonary hypertension in infants with conditions associated with chronic hypoxia. Relevance: Pulmonary hypertension is a well recognized complication of infants with a variety of lung and heart disorders. Currently there are few good options for treating these infants. The goal of this project is to help us understand why infants develop pulmonary hypertension, determine what happens in the lung blood vessels during disease development, and develop treatments for this disease.