Regulation of Vascular Integrity

如本报告的目标和目的部分所述，该项目包括两个具体目标： 研究调节血管完整性的基因 我们已经使用正向遗传筛选来鉴定破坏斑马鱼脑血管完整性的新的斑马鱼突变体，使用外显子组测序和SNP分析以及新开发的SNP数据库来进行突变体的高通量克隆。到目前为止，这些方法已经为大约三分之一的突变体鉴定出了致病基因。我们目前正在进一步鉴定这些突变体中缺陷的分子性质，并继续鉴定其他突变体中的致病遗传缺陷。这些新的血管完整性突变体有望揭示在维持血管屏障功能中重要的新途径。我们还在研究GDF6(BMP13)在血管完整性中的作用，证明该基因通过抑制过量的VEGF信号来促进血管完整性的维持。 支持血管平滑肌细胞的获得及功能研究 内皮细胞周围的血管平滑细胞(VSMC)在调节血管张力和血管完整性方面起着关键作用。我们最近开始使用斑马鱼来研究这些细胞的获取和功能。我们已经开发了一些有用的转基因工具来可视化和实验地操纵斑马鱼中的这一细胞群体，并正在利用这些工具和其他工具来(I)检测这些细胞的起源，(Ii)证明VSMC与内皮的相互作用是维持血管基底膜和限制血管直径所必需的，(Iii)阐明动脉(而不是静脉)选择性获得VSMC的分子途径。

As described in the goals and objectives section of this report, this project consists of two specific aims: Study genes regulating vascular integrity We have used forward-genetic screens to identify new zebrafish mutants that disrupt cranial vascular integrity in the zebrafish, using exome sequencing and SNP analysis with a newly developed SNP database to perform higher-throughput cloning of mutants. These methods have led to the identification of the causative gene for approximately a third of the mutants thus far. We are currently further characterizing the molecular nature of the defects in these mutants, and continuing to identify the causative genetic defects in the other mutants. These new vascular integrity mutants promise to bring to light new pathways important in the maintenance of vascular barrier function. We are also studying the role of GDF6 (BMP13) in vascular integrity, demonstrating that this gene promotes maintenance of vascular integrity by suppressing excess VEGF signaling. Studying the acquisition and function of supporting vascular smooth muscle cells The vascular smooth cells (VSMC) that surround the endothelial tube play a critical role in regulating vascular tone and vascular integrity. We have recently begun examining the acquisition and function of these cells using the zebrafish. We have developed a number of useful transgenic tools to visualize and experimentally manipulate this cell population in the zebrafish, and are using these and other tools to, among other things, (i) examine the origins of these cells from early sclerotome, (ii) demonstrate that VSMC interaction with the endothelium us required to maintain the vascular basement membrane and restrict vessel diameter, (iii) elucidate the molecular pathways responsible for the selective acquisition of VSMC by arteries (as opposed to veins).