αII- spectrin 的缺乏会影响内皮细胞与基质的接触和迁移，导致体外血管生成受损。

BACKGROUND: Precise coordination of cytoskeletal components and dynamic control of cell adhesion and migration are required for crucial cell processes such as differentiation and morphogenesis. We investigated the potential involvement of αII-spectrin, a ubiquitous scaffolding element of the membrane skeleton, in the adhesion and angiogenesis mechanism. METHODS: The cell models were primary human umbilical vein endothelial cells (HUVECs) and a human dermal microvascular endothelial cell line (HMEC-1). After siRNA- and shRNA-mediated knockdown of αII-spectrin, we assessed its expression and that of its partners and adhesion proteins using western blotting. The phenotypes of the control and spectrin-depleted cells were examined using immunofluorescence and video microscopy. Capillary tube formation was assessed using the thick gel Matrigel matrix-based method and a microscope equipped with a thermostatic chamber and a Nikon Biostation System camera. RESULTS: Knockdown of αII-spectrin leads to: modified cell shape; actin cytoskeleton organization with the presence of peripheral actin patches; and decreased formation of stress fibers. Spectrin deficiency affects cell adhesion on laminin and fibronectin and cell motility. This included modification of the localization of adhesion molecules, such as αVβ3- and α5-integrins, and organization of adhesion structures, such as focal points. Deficiency of αII-spectrin can also affect the complex mechanism of in vitro capillary tube formation, as demonstrated in a model of angiogenesis. Live imaging revealed that impairment of capillary tube assembly was mainly associated with a significant decrease in cell projection length and stability. αII-spectrin depletion is also associated with significantly decreased expression of three proteins involved in capillary tube formation and assembly: VE-cadherin, MCAM and β3-integrin. CONCLUSION: Our data confirm the role of αII-spectrin in the control of cell adhesion and spreading. Moreover, our findings further support the participation of αII-spectrin in capillary tube formation in vitro through control of adhesion molecules, such as integrins. This indicates a new function of αII-spectrin in angiogenesis.

背景：细胞骨架成分的精确协调和细胞黏附及迁移的动态控制对于细胞分化和形态发生等关键细胞过程是必需的。我们研究了普遍存在于膜骨架中的αII- spectrin 在黏附和血管生成机制中的潜在作用。

方法：细胞模型为人脐静脉内皮细胞（HUVEC）和人真皮微血管内皮细胞系（HMEC-1）。用 siRNA 和 shRNA 介导的αII- spectrin 敲低后，我们用 Western blot 检测其表达及其伴侣和黏附蛋白的表达。用免疫荧光和视频显微镜观察对照和 spectrin 耗竭细胞的表型。用厚凝胶基质胶（Matrigel）方法和配备有恒温室和 Nikon Biostation 系统相机的显微镜评估毛细血管管腔形成。

结果：αII- spectrin 敲低导致：细胞形状改变；有外周肌动蛋白斑的肌动蛋白细胞骨架组织；和应力纤维形成减少。spectrin 缺乏影响细胞在层粘连蛋白和纤维连接蛋白上的黏附以及细胞迁移。这包括黏附分子如αVβ3-和α5-整合素的定位改变，以及黏附结构如焦点的组织。αII- spectrin 的缺乏也会影响体外毛细血管管腔形成的复杂机制，在血管生成模型中得到了证实。实时成像显示，毛细血管管腔组装受损主要与细胞突起长度和稳定性的显著下降有关。αII- spectrin 耗竭也与参与毛细血管管腔形成和组装的三种蛋白的表达显著下降有关：VE-钙黏蛋白、MCAM 和β3-整合素。

结论：我们的数据证实了αII- spectrin 在控制细胞黏附和铺展中的作用。此外，我们的发现进一步支持了αII- spectrin 通过控制黏附分子如整合素在体外参与毛细血管管腔形成的作用。这表明αII- spectrin 在血管生成中有新的功能。