Dwivedi Amrita, Sala-Newby Graciela B, George Sarah Jane
Bristol Heart Institute, University of Bristol, Bristol Royal Infirmary, Bristol, BS2 8HW, UK.
Basic Res Cardiol. 2008 May;103(3):244-56. doi: 10.1007/s00395-007-0693-9. Epub 2007 Dec 13.
Vascular smooth muscle cell (VSMC) proliferation and migration is responsible for intimal thickening that occurs in restenosis and atherosclerosis. Integrin-linked kinase (ILK) is a serine/threonine protein kinase implicated in signaling pathways involved in cell proliferation and migration. We studied the involvement of ILK in intimal thickening. ILK expression was significantly increased in two models of intimal thickening: balloon-injured rat carotid arteries and human saphenous vein organ cultures. Over-expression of a dominant negative ILK (DN-ILK) significantly reduced intimal thickening by approximately 50% in human saphenous vein organ cultures, demonstrating an important role in intimal thickening. ILK protein and activity was reduced on laminin and up-regulated on fibronectin, indicating ILK protein expression is modulated by extracellular matrix composition. Inhibition of ILK by siRNA knockdown and DN-ILK significantly decreased VSMC proliferation and migration while wild type ILK significantly increased proliferation and migration on laminin, confirming an essential role of ILK in both processes. Localization of paxillin and vinculin and protein levels of FAK and phospho-FAK indicated that inhibition of ILK reduced focal adhesion formation. Additionally, inhibition of ILK significantly attenuated the presence of the cell-cell complex proteins N-cadherin and beta-catenin, and beta-catenin signaling. We therefore suggest ILK modulates VSMC proliferation and migration at least in part by acting as a molecular scaffold in focal adhesions as well as modulating the stability of cell-cell contact proteins and beta-catenin signaling. In summary, ILK plays an important role in intimal thickening by modulating VSMC proliferation and migration via regulation of cell-matrix and cell-cell contacts and beta-catenin signaling.
血管平滑肌细胞（VSMC）的增殖和迁移是导致再狭窄和动脉粥样硬化中内膜增厚的原因。整合素连接激酶（ILK）是一种丝氨酸/苏氨酸蛋白激酶，参与细胞增殖和迁移相关的信号通路。我们研究了ILK在内膜增厚中的作用。在两种内膜增厚模型中，即球囊损伤的大鼠颈动脉和人隐静脉器官培养物中，ILK的表达显著增加。在人隐静脉器官培养物中，显性负性ILK（DN-ILK）的过表达显著降低了内膜增厚约50%，表明其在内膜增厚中起重要作用。ILK蛋白和活性在层粘连蛋白上降低，而在纤连蛋白上上调，表明ILK蛋白表达受细胞外基质组成的调节。通过小干扰RNA敲低和DN-ILK抑制ILK，显著降低了VSMC的增殖和迁移，而野生型ILK在层粘连蛋白上显著增加了增殖和迁移，证实了ILK在这两个过程中的重要作用。桩蛋白和纽蛋白的定位以及粘着斑激酶（FAK）和磷酸化FAK的蛋白水平表明，抑制ILK减少了粘着斑的形成。此外，抑制ILK显著减弱了细胞间复合蛋白N-钙黏着蛋白和β-连环蛋白的存在以及β-连环蛋白信号传导。因此，我们认为ILK至少部分地通过作为粘着斑中的分子支架以及调节细胞间接触蛋白的稳定性和β-连环蛋白信号传导来调节VSMC的增殖和迁移。总之，ILK通过调节细胞-基质和细胞-细胞接触以及β-连环蛋白信号传导来调节VSMC的增殖和迁移，从而在内膜增厚中起重要作用。
