Endothelial Cell Migration in Three Dimensions

项目1：肌球蛋白II介导局部皮质张力以引导内皮细胞分支 三维形态发生和迁移。 人物：罗伯特·费舍尔 血管生成的一个关键特征是对内皮细胞(EC)形态发生和运动的定向控制。在新生血管的萌发过程中，内皮细胞会根据血管内皮生长因子或低氧等生化信号，从现有血管定向分支，迁移并侵入周围的细胞外基质(ECM)，这一过程需要基质金属蛋白酶(MMPs)对ECM进行重塑。端部EC分支是由亚细胞伪足分支的定向突起介导的。在这里，我们试图了解EC伪足分支是如何被局部调控以定向指导血管生成的。我们开发了一个体外三维EC模型系统，其中迁移的EC显示出与活斑马鱼相似的分枝伪足形态动力学。使用这个系统，我们发现细胞外基质的僵硬和岩石介导的肌球蛋白II活性抑制了EC伪足分支的起始。肌球蛋白II动态定位于EC皮质，并在促进分支的条件下部分释放。皮质肌球蛋白II的局部耗竭先于分支的启动，而肌球蛋白II的局部抑制可以诱导分支的启动。因此，肌球蛋白II皮质收缩的局部下调允许伪足起始介导EC分支，从而引导定向迁移和血管生成。 这项工作是与鲍勃·阿德尔斯坦、马雪飞(NHLBI)和玛格丽特·加德尔(U Chicago)合作完成的，并于2009年出版 项目2：开发三维追踪细胞形态动力学的算法。 人物：罗伯特·费舍尔 与Gaudenz Danuser和Sam Ching合作在斯克里普斯演出，并在伍兹霍尔的MBL演出。这一过程正在进行中。

Project 1;Myosin II mediates local cortical tension to guide endothelial cell branching morphogenesis and migration in 3D. Personell: Robert Fischer A key feature of angiogenesis is directional control of endothelial cell (EC) morphogenesis and movement. During angiogenic sprouting, endothelial tip cells directionally branch from existing vessels in response to biochemical cues such as VEGF or hypoxia, and migrate and invade the surrounding extracellular matrix (ECM) in a process that requires ECM remodeling by matrix metalloproteases (MMPs). Tip EC branching is mediated by directional protrusion of subcellular pseudopodial branches. Here we sought to understand how EC pseudopodial branching is locally regulated to directionally guide angiogenesis. We develop an in vitro 3D EC model system where migrating ECs display branched pseudopodia morphodynamics similar to those in living zebrafish. Using this system, we find that ECM stiffness and ROCK-mediated myosin II activity inhibit EC pseudopodial branch initiation. Myosin II is dynamically localized to the EC cortex, and is partially released under conditions that promote branching. Local depletion of cortical myosin II precedes branch initiation, and initiation can be induced by local inhibition of myosin II activity. Thus, local downregulation of myosin II cortical contraction allows pseudopodium initiation to mediate EC branching and hence guide directional migration and angiogenesis. This work was performed in collaboration with Bob Adelstein and Xuefei Ma (NHLBI) and Margaret Gardel (U Chicago) and was published in 2009 Project 2: Development of algorithms for tracking cell morphodynamics in three dimensions. Personell: Robert Fischer In collaboration with Gaudenz Danuser and Sam Ching at Scripps and performed at MBL at Woods Hole. This is ongoing.