Competition and morphogenesis in tip cell-mediated branching of tubular networks

Ghabrial--项目摘要 为了建立一个有功能的血管系统，必须通过组合产生内皮管网络 血管生成和血管生成。在萌芽血管生成过程中，内皮尖细胞引导血管生成 新的分支机构。顶端细胞与其他顶端细胞或与预先存在的管吻合。同时，TIP细胞 还必须使管子流明，这样管子才能成为专利。对斑马鱼的研究表明，顶端细胞通过一种 在横截面上没有接缝的细胞内管(无缝管)的过程。偶数尖端细胞 即后来改型为多细胞管，通过无缝管中间阶段。 同样，在果蝇呼吸系统的初级分支期间，气管尖端细胞领导着 新的分支机构。为了形成网络，一些气管尖端细胞吻合(融合细胞)，而另一些(末端细胞) 细胞)广泛地分支以产生数十个盲端管，这些管在靶组织上分支并充当 气体交换地点。像内皮细胞一样，气管顶端细胞形成无缝的管子。细胞生物学研究 导致了当前通过反相膜鼓泡形成无缝管的模型；然而，很少有 了解所需的遗传和分子途径。我们一直在剥削强大的 在果蝇中可能采用的正向遗传方法，以满足我们开创 了解制造、塑造和维护无缝管所需的遗传和分子框架。 我们方法的基本原理是，在果蝇中运行的基本规则和遗传途径是 很可能会在整个动物界得到保护。当我们通过识别小说来建立我们的理解时 无缝管形态发生所需的基因(目标1：确定无缝管的分子特性和功能 囊腔基因。)，我们也更深入--使用分子遗传学、细胞学和蛋白质组学方法-- 为了确定我们之前已有的遗传途径的其他成分和作用机制 确定，并将我们的发现扩展到内皮无缝管(目标2：阐明细胞和 TBC1D10和Rab35在无缝管生长中作用的分子机制)。此外，还有一个 无缝小管生成途径(脑海绵状血管畸形3-生发中心激酶III 途径)，已知在内皮细胞中是关键的，因为同源人类基因的突变 导致家族性血管疾病。利用果蝇遗传和蛋白质组学方法，我们已经识别出 CCM3-GCKIII途径上游和下游都需要的因素，现在提出了更多 明确定义干扰该途径的生物学后果并确定其下游靶点 信号通路。鉴于CCM3在小管发生中的保守作用，我们还试图扩展我们的结果 脊椎动物的内皮系统，利用斑马鱼的独特特性，将使基因 血管病变形成的操作和活体成像(目的3：表征血管病变形成的作用 NDR激酶，三角体，调节无缝管的形状。

Ghabrial – Project Summary To build a functional vascular system, a network of endothelial tubes must be generated through a combination of vasculogenesis and angiogenesis. During sprouting angiogenesis, endothelial tip cells lead the outgrowth of new branches. Tip cells anastomose with other tip cells or with pre-existing tubes. At the same time, tip cells must also lumenize so that the tubes become patent. Studies in zebrafish indicate tip cells lumenize by a process that an intracellular tube that, in cross section, lacks junctional seams (seamless tube). Even tip cells that later remodel to contribute to multicellular tubes, pass through a seamless tube intermediate stage. Likewise, during primary branching of the Drosophila respiratory system, tracheal tip cells lead the outgrowth of new branches. To form a network, some tracheal tip cells anastomose (fusion cells) while others (terminal cells) branch extensively to produce dozens of blind ended tubes that ramify on target tissues and act as the sites of gas exchange. Like endothelial tip cells, tracheal tip cells form seamless tubes. Cell biological studies have led to the current model of seamless tube formation by inverse membrane blebbing; however, very little is known about the genetic and molecular pathways that are required. We have been exploiting the powerful forward genetic approaches possible in Drosophila to meet our long-term objective of pioneering an understanding of the genetic and molecular framework required to make, shape and maintain seamless tubes. The rationale of our approach is that the fundamental rules and genetic pathways operative in Drosophila are likely to be conserved throughout the animal kingdom. As we build our understanding by identifying novel genes required for seamless tube morphogenesis (AIM 1: Determine the molecular identity and function of the cystic lumens gene.), we also go deeper – using molecular genetic, cellular, and proteomic approaches – to identify additional components and mechanisms of action for genetic pathways we have previously identified, and extending our findings to endothelial seamless tubes (AIM 2: Elucidate the cellular and molecular mechanisms of TBC1D10 and Rab35 action in seamless tube growth). Additionally, one seamless tubulogenesis pathway (the Cerebral Cavernous Malformations 3-Germinal Center Kinase III pathway) we identified, is known to be critical in endothelial cells, as mutations in orthologous human genes lead to familial vascular disease. Using Drosophila genetic and proteomic approaches, we have identified factors required both upstream and downstream in the CCM3-GCKIII pathway, and now propose to more clearly define the biological consequences of perturbing the pathway and to identify the downstream targets of the signaling pathway. Given the conserved role of CCM3 in tubulogenesis, we also seek to extend our results to the vertebrate endothelial system, making use of zebrafish, whose unique properties will allow both genetic manipulation and live imaging in vivo of vascular lesion formation (AIM 3: To characterize the role of the NDR kinase, Tricornered, in regulating seamless tube shape.).