Coordination of pulmonary vascular development by Prx1

描述(申请人提供)：同源框基因编码转录因子，控制组织模式和形态发生，但它们在肺血管发育中的作用仍不清楚。我们的初步研究表明，配对相关的同源盒基因PrXL是肺血管形成所必需的，它通过促进内皮细胞(EC)分化和血管网络形成的能力。本研究的具体目的如下：(1)明确PRXL在肺血管生成过程中如何促进EC分化：将利用Tie-GFP转基因小鼠在整个肺发育过程中定位表达PRXL的ECs，并利用染色质免疫沉淀实验确定PRXL在肺内皮细胞分化中的直接靶点。PRXL及其靶点的有效性和功能将通过PRXL缺失的小鼠和肺内皮细胞分化的组织培养模型进行评估：(2)确定PRXL依赖的细胞外基质蛋白TN-C(TN-C)的诱导如何促进肺血管网络的形成：将使用胎肺外植体、酵母双杂交和组织重组进行基因敲除研究，以了解TN-C如何促进PRXL依赖的网络的形成；(3)阐明粘着斑激酶(FAK)在血管网络形成过程中是如何调控PRXL的：基于腺病毒的FAK活性抑制和PRXL基因启动子的解剖将被用来理解FAK是如何控制肺中PRXL转录和血管形态发生的。 总体而言，这项建议将导致对PRXL在胎儿肺血管形成过程中的作用有一个详细的了解。这项研究将为肺血管生物学提供新的概念，并有望为治疗肺血管受损的新生儿和成人疾病带来新的诊断工具和治疗方法。支气管肺发育不良和肺动脉高压。

DESCRIPTION (provided by applicant): Homeobox genes encode transcription factors that control tissue patterning and morphogenesis, yet their role in pulmonary vascular development remains obscure. Our preliminary studies indicate that the paired related homeobox gene, Prxl, is required for lung vascularization via its ability to promote both endothelial cell (EC) differentiation and vascular network formation. The Specific Aims of this proposal are as follows: (1) To define how Prxl drives EC differentiation during lung vasculogenesis: Tie-GFP transgenic mice will be used to locate Prxl-expressing ECs throughout lung development, and chromatin immunoprecipitation assays will be used to identify direct targets for Prxl in differentiating lung ECs. The validity and functions of Prxl and its targets will be evaluated using Prxl-null mice and tissue culture models of pulmonary EC differentiation; (2) To determine how Prxl-dependent induction of the extracellular matrix protein tenascin- C (TN-C) promotes lung vascular network formation: Knockout studies using fetal lung explants, yeast 2- hybrid assays and tissue recombinations will be used to understand how TN-C promotes Prxl-dependent network formation; (3) To delineate how focal adhesion kinase (FAK) controls Prxl during vascular network formation: Adenoviral-based inhibition of FAK activity, and dissection of the Prxl gene promoter will be used to comprehend how FAK controls Prxl transcription and vascular morphogenesis in the lung. Overall, this proposal will result in a detailed understanding of the role of Prxl throughout fetal lung vascularization. This study should provide new concepts in lung vascular biology, and will hopefully result in novel diagnostic tools and therapies for the treatment of newborn and adult diseases in which the pulmonary vasculature is compromised, eg. bronchopulmonary dysplasia and pulmonary hypertension.