Disciplina de Biologia Molecular, Departamento de Bioquímica, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brazil.
Disciplina de Biologia Molecular, Departamento de Bioquímica, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brazil; Institute of Integrative Biology, Department of Biochemistry, University of Liverpool, Liverpool, UK.
Matrix Biol. 2017 Nov;63:23-37. doi: 10.1016/j.matbio.2016.12.006. Epub 2017 Jan 4.
Syndecans are heparan sulfate proteoglycans characterized as transmembrane receptors that act cooperatively with the cell surface and extracellular matrix proteins. Syn4 knockdown was performed in order to address its role in endothelial cells (EC) behavior. Normal EC and shRNA-Syn4-EC cells were studied comparatively using complementary confocal, super-resolution and non-linear microscopic techniques. Confocal and super-resolution microscopy revealed that Syn4 knockdown alters the level and arrangement of essential proteins for focal adhesion, evidenced by the decoupling of vinculin from F-actin filaments. Furthermore, Syn4 knockdown alters the actin network leading to filopodial protrusions connected by VE-cadherin-rich junction. shRNA-Syn4-EC showed reduced adhesion and increased migration. Also, Syn4 silencing alters cell cycle as well as cell proliferation. Moreover, the ability of EC to form tube-like structures in matrigel is reduced when Syn4 is silenced. Together, the results suggest a mechanism in which Syndecan-4 acts as a central mediator that bridges fibronectin, integrin and intracellular components (actin and vinculin) and once silenced, the cytoskeleton protein network is disrupted. Ultimately, the results highlight Syn4 relevance for balanced cell behavior.
黏附素是带有硫酸肝素蛋白聚糖的跨膜受体，其特征在于与细胞表面和细胞外基质蛋白协同作用。为了研究其在内皮细胞（EC）行为中的作用，进行了 Syn4 敲低。使用互补的共聚焦、超分辨率和非线性显微镜技术，比较研究了正常 EC 和 shRNA-Syn4-EC 细胞。共聚焦和超分辨率显微镜显示，Syn4 敲低会改变参与黏附斑的必需蛋白的水平和排列，这表现为 vinculin 与 F-肌动蛋白丝的解偶联。此外，Syn4 敲低会改变肌动蛋白网络，导致富含 VE-钙黏蛋白的连接连接的丝状伪足突出。shRNA-Syn4-EC 表现出黏附减少和迁移增加。此外，Syn4 沉默会改变细胞周期和细胞增殖。此外，当沉默 Syn4 时，EC 在基质胶中形成管状结构的能力降低。总之，这些结果表明，黏附素-4 作为一种中央介质，桥接纤连蛋白、整合素和细胞内成分（肌动蛋白和 vinculin），一旦沉默，细胞骨架蛋白网络就会被破坏。最终，这些结果强调了 Syn4 对平衡细胞行为的重要性。
