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。 个人：Robert Fischer 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。在血管生成出芽过程中，内皮尖端细胞响应于生物化学信号（如VEGF或缺氧）从现有血管定向分支，并在需要基质金属蛋白酶（MMP）重塑ECM的过程中迁移和侵入周围的细胞外基质（ECM）。 顶端EC分支由亚细胞伪足分支的定向突起介导。 在这里，我们试图了解EC伪足分支是如何局部调节，定向引导血管生成。我们开发了一个体外三维EC模型系统，迁移EC显示分支伪足形态动力学类似于那些在活斑马鱼。使用这个系统，我们发现ECM刚度和ROCK介导的肌球蛋白II活性抑制EC伪足分支的启动。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的局部消耗先于分支起始，并且起始可以通过肌球蛋白II活性的局部抑制来诱导。因此，肌球蛋白II皮质收缩的局部下调允许伪足启动介导EC分支，从而引导定向迁移和血管生成。 这项工作是与Bob Adelstein和Xuefei Ma（NHLBI）以及Margaret Gardel（U芝加哥）合作完成的，并于2009年出版 项目2：开发三维跟踪细胞形态动力学的算法。 个人：Robert Fischer 与斯克里普斯的高登兹·达努瑟和萨姆·程合作，并在伍兹霍尔的MBL演出。 这项工作正在进行中。

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.