LUNG ELASTIN IN BRONCHOPULMONARY DYSPLASIA

支气管肺发育不良中的肺弹性蛋白

• 批准号: 7349770
• 负责人: Richard A Pierce
• 金额: $ 3.55万
• 依托单位: TEXAS BIOMEDICAL RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7349770
• 关键词: LUNG; ELASTIN; BRONCHOPULMONARY; DYSPLASIA

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 focus of this proposal is to characterize mechanisms controlling elastin synthesis and turnover during the development of bronchopulmonary dysplasia (BPD) resulting from ventilation of the premature lung. Elastin confers the requisite property of elastic recoil to such lung structures as alveoli and alveolar ducts, bronchioles, and blood vessels, and thus is essential for lung function. We have previously demonstrated abnormal elastic fiber deposition in an experimental model of BPD, and others have demonstrated increased elastolytic activity in the BPD lung. Still, the root causes of elastic fiber abnormalities in BPD are not known. We hypothesize that mesenchymal cells of the premature lung respond to the strain of mechanical ventilation by increasing the expression and deposition of elastic extracellular matrix components out of proportion to what is required for alveolarization. Exposure to hyperoxia may result in the production and release of elastases such as neutrophil elastase or matrix metalloproteinases that damage elastic fibers, as well as cytokines or growth factors that alter extracellular matrix gene expression by lung fibroblasts. These events result in the excess deposition of disordered elastic fibers at sites of failed development of new alveolar walls. The accumulation of disorganized elastic fibers at these sites may limit the ability to recover from injury. To determine the causes of abnormal elastic fiber deposition during the development of BPD, we propose to study the expression of elastin, fibrillins1 and 2, and lysyl oxidase, all required for normal elastic fiber synthesis, and to characterize the elastases present in the injured lung. Our experimental approaches will include quantitative analysis of elastic fiber-related and elastase mRNA expression by RNAse protection assays, as well as localization of expression by in situ hybridization and immunohistochemical analyses. The molecular mechanisms regulating tropoelastin expression during normal baboon lung development and the development of BPD will be determined by assessing changes in tropoelastin gene transcription, steady-state mRNA levels, and protein synthesis, expression and activity of elastases in the BPD lung will be assessed by a combination of substrate zymography, immunohistochemistry, and in situ hybridization. Determining the effects of interventive treatments on the expression of elastic fiber-related genes and the elaboration of elastases will test the hypothesis that treatment which prevent BPD will also restore normal patterns of elastic fiber-related gene expression and elastic fiber deposition.

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。本建议的重点是表征机制控制弹性蛋白的合成和营业额在支气管肺发育不良（BPD）的发展导致过早的肺通气。弹性蛋白赋予肺结构如肺泡和肺泡管、细支气管和血管必要的弹性回缩性质，因此对于肺功能是必需的。我们先前已经证明了BPD实验模型中的异常弹性纤维沉积，并且其他人已经证明了BPD肺中弹性蛋白溶解活性的增加。尽管如此，BPD弹性纤维异常的根本原因尚不清楚。我们假设，早产儿肺间充质细胞通过增加弹性细胞外基质成分的表达和沉积来响应机械通气的应变，而这些成分与肺泡化所需的成分不成比例。暴露于高氧可能导致弹性蛋白酶的产生和释放，例如损害弹性纤维的中性粒细胞弹性蛋白酶或基质金属蛋白酶，以及改变肺成纤维细胞的细胞外基质基因表达的细胞因子或生长因子。这些事件导致在新肺泡壁发育失败的部位无序弹性纤维的过度沉积。在这些部位的无序弹性纤维的积累可能会限制从损伤中恢复的能力。为了确定BPD发展过程中异常弹性纤维沉积的原因，我们建议研究弹性蛋白、原纤维蛋白1和2以及赖氨酰氧化酶的表达，这些都是正常弹性纤维合成所需的，并表征受伤肺中存在的弹性蛋白酶。我们的实验方法将包括定量分析的弹性纤维相关和弹性蛋白酶mRNA的表达RNA酶保护试验，以及通过原位杂交和免疫组织化学分析的表达定位。将通过评估原弹性蛋白基因转录、稳态mRNA水平和蛋白质合成的变化来确定在正常狒狒肺发育和BPD发育期间调节原弹性蛋白表达的分子机制，将通过底物酶谱、免疫组织化学和原位杂交的组合来评估BPD肺中弹性蛋白酶的表达和活性。确定干预性治疗对弹性纤维相关基因表达和弹性蛋白酶表达的影响，将检验预防BPD的治疗也将恢复弹性纤维相关基因表达和弹性纤维沉积的正常模式的假设。