Genetic Investigation of pulmonary lymphatic development and function

描述（由申请方提供）：在美国，与肺发育不成熟相关的呼吸窘迫综合征（RDS）每年影响超过16，000例早产儿。RDS的发病机制主要归因于缺乏表面活性剂，表面活性剂是一种蛋白质-脂质复合物，其需要改善肺顺应性并使新生儿能够充气和呼吸。淋巴管在妊娠中期出现在肺中，并被认为在为分娩和新生儿呼吸做准备时排出肺中的液体中发挥作用。然而，研究，以确定肺淋巴管的作用，利用导管为基础的和手术方法开发的血管调查没有发现任何关键作用，新生儿呼吸。我们使用缺乏淋巴功能的转基因小鼠进行的初步研究反驳了这些结论，并揭示缺乏淋巴管的小鼠在出生时由于缺乏肺膨胀和新生儿呼吸衰竭而死亡。我们对缺乏淋巴管生成因子CCBE 1或VEGFR 3受体信号传导的小鼠的研究没有揭示肺发育中的任何分子或细胞异常。相反，我们发现淋巴功能的丧失与产前肺顺应性降低有关，尽管保留了表面活性物质的产生。这项提案的目标是充分确定淋巴如何在哺乳动物肺中发展，以及它们在该器官中的产前和新生儿功能是什么。在目标1中，我们将研究淋巴管发育的分子和细胞过程中使用新产生的小鼠淋巴管生成因子的表达，可以遵循报告基因，并通过条件基因缺失改变。在目标2中，我们将定义一个新的机械作用的淋巴功能，在调节发展和新生儿肺的顺应性。我们希望这些研究能确定淋巴在新生儿呼吸中的新作用，并刺激 开发新的基于药物的策略来治疗早产儿RDS。

DESCRIPTION (provided by applicant): Respiratory distress syndrome (RDS) associated with immature lung development affects over 16,000 premature infants annually in the US. The pathogenesis of RDS is attributed primarily to the lack of surfactant, a protein-lipid complex required to improve lung compliance and enable newborn infants to inflate their lungs and breath. Lymphatic vessels appear in the lung in mid- gestation and have been proposed to play roles in draining the lung of fluid in preparation for birth and neonatal respiration. However, studies to define the role of pulmonary lymphatic vessels utilizing catheter-based and surgical approaches developed for blood vessel investigation have not revealed any critical roles in neonatal respiration. Our preliminary studies using genetically modified mice that lack lymphatic function refute these conclusions, and reveal that mice lacking lymphatic vessels die at birth due to lack of lung inflation and neonatal respiratory failure. Our studies of mice lacking the lymphangiogenic factor CCBE1 or signaling by the VEGFR3 receptor do not reveal any molecular or cellular abnormalities in lung development. Instead, we find that loss of lymphatic function is associated with reduced prenatal lung compliance despite preserved surfactant production. The goal of this proposal is to fully define how lymphatic's develop in the mammalian lung and what their prenatal and neonatal functions in that organ are. In Aim 1 we will study the molecular and cellular processes of lymphatic vascular development using newly generated lines of mice in which lymphangiogenic factor expression can be followed by reporter genes and altered through conditional gene deletion. In Aim 2 we will define a new mechanical role of lymphatic function in regulating the compliance of the developing and neonatal lung. We expect these studies to define a new role for lymphatic's in neonatal respiration, and to stimulate the development of new lymphatic-based strategies to treat RDS in premature infants.