Microvascular Remodeling in Development

描述（由申请人提供）：该提案的重点是RhoB在血管和淋巴血管生成中的作用。使用的模型包括新生儿视网膜新生血管和皮肤血管生成和淋巴管生成。这项资助申请的总体假设是RhoB通过调节转录因子Db1/Vezf1的转录活性来促进血管内皮表型并抑制淋巴分化。目的1：确定利用RhoB和Db1/VEZF的血液和淋巴功能。在此目的中，我们将完成RhoB缺失小鼠视网膜血管和皮肤血管和淋巴表型的检查，以及RhoB和vezf1的交叉。我们还将使淋巴细胞和血液内皮细胞形成杂交小鼠，并检查对增殖，存活和管形成的功能影响。我们发现RhoB和Db1 （VEZF1的人类同源物）对内皮细胞中VEGF受体的表达有相似的影响，特别是它们协同调节Nrp1的表达。我们有新的数据表明，当我们用野生型Db1而不是带点突变的Db1共转染表达质粒时，我们可以以Db1依赖的方式免疫沉淀nrp1启动子与RhoB的相互作用。这一目的将使这些研究进一步深入，更全面地了解RhoB和Db1靶基因的协同调控。公共卫生相关性：有点令人惊讶的是，我们对淋巴遗传学和分子生物学的了解远远落后于它们的姊妹网络——血管系统。我们的申请旨在研究RhoB和Db1协同调节视网膜血管生成、皮肤血管生成和淋巴管生成的生物学和分子机制。这些发现的疾病相关性可能影响视网膜血管疾病，如糖尿病视网膜病变和黄斑变性，以及多种情况下的伤口愈合。

DESCRIPTION (provided by applicant): This proposal is focused on the role of RhoB in vascular and lymphatic angiogenesis. The models used include neonatal retinal neovascularization and skin angiogenesis and lymphangiogenesis. The overall hypothesis of this grant application is that RhoB promotes vascular endothelial phenotypes and inhibits lymphatic differentiation by regulating the transcriptional activity of the transcription factor Db1/Vezf1. Aim 1: Determine blood and lymphatic functions that utilize RhoB and Db1/VEZF In this aim we will complete the examination of the retinal vascular and skin vascular and lymphatic phenotypes in RhoB null mice, and rhoB and vezf1 intercrosses. We will also make lymphatic and blood endothelial cells form the intercrossed mice and examine functional effects on proliferation, survival and tube formation. Aim 2: Determine the mechanisms of RhoB and Db1/VEZF1 collaboration on gene expression We show evidence that RhoB and Db1 (human homologue of Vezf1) have similar effects on expression of VEGF receptors in endothelial cells and that they collaborate to regulate expression of Nrp1 in particular. We have new data that we can immunoprecipitate the nrp1 promoter with RhoB in a Db1 dependent manner that is when we co-transfect an expression plasmid with wild type Db1 but not Db1 with a point mutation that blocks its interaction with RhoB. This aim will extend these studies to more fully understand the co-regulation of target genes of RhoB and Db1. PUBLIC HEALTH RELEVANCE: Somewhat surprisingly, our knowledge of lymphatic genetics and molecular biology has lagged significantly behind that of their sister network, the blood vasculature. Our application proposes to study the biology and molecular mechanisms that RhoB and Db1 use to collaborate to regulate retinal angiogenesis and skin angiogenesis and lymphangiogenesis. The disease relevance of these findings could impact both retinal vascular diseases such as diabetic retinopathy and macular degeneration as well as wound healing in multiple settings.