Prostanoids and Hypoxic Neonatal Pulmonary Hypertension

描述(申请人提供)：预防新生儿肺动脉高压发生或发展的治疗方法很少受到关注，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性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，在低氧暴露的3天内，前列腺素和NADPH氧化酶信号发生中断，这介导了平滑肌细胞(SMC)活性氧(ROS)的产生和电压门控K+(Kv)通道功能的变化。这些变化产生了一个自我维持血管功能障碍的前馈过程，当缺氧延长到10天时，这种过程会被放大。具体的假设是：(1)慢性低氧激活前列腺素和NADPH氧化酶途径，导致肺阻力动脉(PRAs)SMC产生前列腺素和ROS增加，进而损害SMC Kv通道功能，导致SMC膜(Em)去极化和胞浆钙浓度升高。具体目标1将确定缺氧3天或10天对(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、光敏素衍生的化学发光、氧化剂敏感的荧光染料和培养的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(酶分析)和优势细胞位置(免疫组织化学)。关键发现将通过体内研究进行验证。具体目标2将评估缺氧3天或10天对(A)Kv通道对血管紧张性(管状动脉)的贡献(B)SMC Em(微电极)，(C)SMC钙(荧光)和(D)Kv通道数量(免疫印迹)的影响。我们的发现将提供所需的新信息，以设计治疗方法来干预与慢性缺氧相关的婴儿的肺动脉高压的发展。相关性：肺动脉高压是公认的婴幼儿各种肺和心脏疾病的并发症。目前，治疗这些婴儿的好选择寥寥无几。这个项目的目标是帮助我们了解婴儿为什么会患上肺动脉高压，确定在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.