Control of Angiogenesis in neonatal Hyperoxic Lung Injury

描述（由申请人提供）：支气管肺发育不良（BPD）是一个重要的健康问题，每年的医疗费用为40亿美元。在儿童保健费用中，这仅次于哮喘。了解BPD发病机制的一个主要空白是了解调节肺泡单位（此处定义为肺泡上皮和底层微血管床）发育的相互作用信号，以及这些相互作用信号如何被高氧破坏。我们的长期目标是了解BPD中肺泡单位发育中断的机制。我们的主要目标是利用候选分子方法，通过血管抑制剂的研究，深入了解肺泡单位正常和氧损伤发育的机制。我们的主要候选因子是色素上皮衍生因子（PEDF）及其上游调节因子Kringle 5 （K5）。微血管形成过程与肺泡形成过程密切相关。血管生成受促血管生成和抗血管生成信号之间的平衡密切调节。高氧破坏这种平衡可能导致肺泡单位发育异常。我们证明新生儿高氧肺损伤与PEDF增加有关，特别是在肺泡嵴、II型细胞和内皮细胞中，而血管内皮生长因子（VEGF）减少。我们将在体内和体外研究PEDF诱导或抑制对肺泡形成和微血管形成的影响，并研究其抑制血管生成的机制。我们假设新生儿肺部的高氧损伤破坏了血管生成和血管抑制信号的正常平衡，导致肺泡形成所需的微血管发育受损。我们拟研究PEDF对新生小鼠肺和肺内皮细胞肺泡形成和血管生成的抑制作用。我们将确定PEDF下调VEGF生成和活性的机制，以及PEDF发挥其作用的机制。最后，我们将研究PEDF上游近端血管他汀类药物，特别是Kringle 5。Kringle 5是由基质金属蛋白酶9 （MMP-9）作用产生的，我们发现在新生儿肺氧损伤和肺泡生成停止中，基质金属蛋白酶9显著上调。我们将确定在高氧状态下血管抑制作用是否由MMP-9 - K5 - PEDF通路驱动。这些研究为BPD患者肺泡单位发育改变机制的研究开辟了新的方向，具有创新性。这一建议的影响将是BPD的一种新的机制途径的发展，这可能导致新的治疗策略。

DESCRIPTION (provided by applicant): Bronchopulmonary Dysplasia, (BPD) is a significant health problem, accounting for $4 Billion in annual health care costs. This is second only to asthma in child health care costs. A major gap in understanding the pathogenesis of BPD is knowledge of interacting signals regulating the development of the alveolar unit (defined here as the alveolar epithelium and the underlying microvascular bed), and how these interacting signals are disrupted by hyperoxia. Our long term goal is to develop an understanding of the mechanisms of disrupted development of the alveolar unit in BPD. Our main objective is to develop mechanistic insight into normal and oxygen-injured development of the alveolar unit through study of angiostatic, using a candidate molecule approach. Our primary candidates are Pigment Epithelium Derived Factor (PEDF), and its upstream regulator Kringle 5 (K5). The processes of microvascularization and alveolarization are closely connected. Angiogenesis is closely regulated by a balance between pro- and anti-angiogenic signaling. Disruption of this balance by hyperoxia could cause abnormal development of alveolar units. We demonstrated that neonatal hyperoxic lung injury is associated with increased PEDF, particularly in alveolar crests, type II cells, and endothelial cells, while vascular endothelial growth factor (VEGF) is decreased. We will study the effect of PEDF induction or inhibition in vivo and in vitro on alveolarization and microvascularization, and study the mechanisms by which it inhibits angiogenesis. We hypothesize that hyperoxic injury in the neonatal lung disrupts the normal balance of angiogenic and angiostatic signaling, causing impaired microvascular development needed for proper alveolarization. We propose to study inhibition by PEDF of alveolarization and angiogenesis in neonatal mouse lungs and mouse lung endothelial cells. We will determine the mechanisms by which PEDF downregulates VEGF production and activity, and by which PEDF exerts its action. Finally, we will look upstream of PEDF at proximal angiostatins, particularly Kringle 5. Kringle 5 is produced by matrix metalloproteinase 9 (MMP-9) action, which we showed is significantly upregulated in neonatal lung oxygen injury and arrests alveologenesis. We will determine if angiostatic effects in hyperoxia are driven by a MMP-9 - K5 - PEDF pathway. These studies are innovative since they develop a new direction for studying mechanisms altering development of the alveolar unit in BPD. The impact of this proposal will be the development of a novel mechanistic pathway for BPD which could lead to new therapeutic strategies.