NITRIC OXIDE SYNTHASES IN LUNG DEVELOPMENT AND BRONCHOPULMONARY DYSPLASIA

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 信号分子一氧化氮(NO)在发育中的肺的气道和血管功能中起重要作用。NO由一氧化氮合酶(NOS)、神经型一氧化氮合酶(NNOS)、内皮型一氧化氮合酶(ENOS)和诱导型一氧化氮合酶(INOS)三种亚型产生。我们的初步研究表明，这三种异构体均在呼吸道上皮细胞中表达，并且nNOS和eNOS在妊娠晚期表达上调，以促进围产期NO的产生。支气管肺发育不良(BPD)是一种干扰早产儿肺发育的炎症性疾病，以呼吸道和肺血管功能障碍为特征。我们在恒河猴BPD模型上的初步研究表明，在BPD的发生过程中，肺组织中NO的产生以及肺组织中nNOS和eNOS的表达均显著降低，吸入NO可持续改善氧合指数。这项建议的总体目标是研究一氧化氮合酶表达的变化在恒河猴BPD模型中的病理生理学中的作用。初步假设在BPD的发生发展过程中，肺组织中nNOS和eNOS的表达下调，导致NO的产生减少，导致气道和血管结构和功能的异常。第二种假设是iNO逆转了这些异常。目的1确定BPD早期正常个体发育及一氧化氮合酶(NOS)蛋白和mRNA表达的变化，采用激光捕获显微切割等方法评价冰冻切片中特定细胞类型的NOS mRNA水平。目的2确定各NOS亚型在完整动物气道和血管功能中的作用。目的3揭示呼出NO水平随胎儿发育和BPD的变化，以及各一氧化氮合酶亚型对呼出NO的贡献。目的4确定iNO对BPD早期肺过程和肺组织学改变、对气道和血管功能的影响。目的5探讨恒河猴呼吸道上皮细胞原生型nNOS和eNOS基因表达的机制，以及细胞因子在其下调中的作用。这些结果将增加我们对NO在正常情况下成功的出生后肺适应和BPD的病理生理学中的作用的了解，从而可能导致这种毁灭性疾病的新疗法。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The signaling molecule nitric oxide (NO) is critically involved in airway and vascular function in the developing lung. NO is produced by three isoforms of NO synthase (NOS), neuronal NOS (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS). Our preliminary work in normal baboon fetuses indicates that all three isoforms are expressed in airway epithelium, and that nNOS and eNOS are upregulated during late gestation to optimize No production in the perinatal period. Bronchopulmonary dysplasia (BPD) is an inflammatory condition which disrupts the development of the preterm human lung, and it is characterized by airway and pulmonary vascular dysfunction. Our initial studies in the baboon BPD model indicate that lung NO production and lung nNOS and eNOS expression are markedly attenuated during the genesis of BPD, and that NO replacement by inhalation (iNO) results in a sustained improvement in oxygenation index. The overall objective of this proposal is to investigate the role of alterations in NOS expression in the pathopysiology of BPD in the baboon model. The primary hypothesis is that pulmonary nNOS and eNOS expression are downregulated during the development of BPD, leading to diminished NO production and abnormal airway and vascular structure and function. The secondary hypothesis is that iNO reverses these abnormalities. Aim 1 is to define the normal ontogeny and changes in NOS protein and mRNA expression in early BPD, using approaches including laser capture microdissection to evaluate NOS mRNA levels in specific cell types harvested from frozen sections Aim 2 is to determine the role of each NOS isoform in airway and vascular function in studies of NOS antagonism in intact animals. Aim 3 is to reveal the changes in exhaled NO levels with fetal development and BPD, as well as the contribution of each NOS isoform to exhaled NO. Aim 4 is to determine the effects of iNO on airway and vascular function, on the pulmonary course of early BPD, and on lung histology. Aim 5 is to determine the mechanisms underlying constitutive nNOS and eNOS gene expression in cultured in baboon airway epithelium, and the role of cytokines in their downregulation. The results obtained will increase our knowledge of the role of NO in normally successful postnatal pulmonary adaptation and in the pathophysiology of BPD, thereby possibly leading to novel therapies for this devastating disorder.