Molecular Cell Biology Laboratory, Department of Plasma Proteins, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, 1066 CX Amsterdam, the Netherlands.
Department of Medical Biochemistry, Amsterdam Cardiovascular Sciences, Academic Medical Center, 1105 AZ Amsterdam, the Netherlands.
Cell Rep. 2018 Sep 18;24(12):3115-3124. doi: 10.1016/j.celrep.2018.08.045.
Leukocytes follow the well-defined steps of rolling, spreading, and crawling prior to diapedesis through endothelial cells (ECs). We found increased expression of DLC-1 in stiffness-associated diseases like atherosclerosis and pulmonary arterial hypertension. Depletion of DLC-1 in ECs cultured on stiff substrates drastically reduced cell stiffness and mimicked leukocyte transmigration kinetics observed for ECs cultured on soft substrates. Mechanistic studies revealed that DLC-1-depleted ECs or ECs cultured on soft substrates failed to recruit the actin-adaptor proteins filamin B, α-actinin-4, and cortactin to clustered ICAM-1, thereby preventing the ICAM-1 adhesome formation and impairing leukocyte spreading. This was rescued by overexpressing DLC-1, resulting in ICAM-1 adhesome stabilization and leukocyte spreading. Our results reveal an essential role for substrate stiffness-regulated endothelial DLC-1, independent of its GAP domain, in locally stabilizing the ICAM-1 adhesome to promote leukocyte spreading, essential for efficient leukocyte transendothelial migration.
白细胞在通过内皮细胞（EC）渗出之前，会沿着滚动、铺展和爬行的明确步骤进行。我们发现 DLC-1 在动脉粥样硬化和肺动脉高压等与僵硬相关的疾病中的表达增加。在硬基底上培养的 EC 中耗尽 DLC-1，会大大降低细胞的刚性，并模拟在软基底上培养的 EC 中观察到的白细胞迁移动力学。机制研究表明，耗尽 DLC-1 的 EC 或在软基底上培养的 EC 无法募集肌动蛋白接头蛋白细丝蛋白 B、α-辅肌动蛋白-4 和纽蛋白到聚集的 ICAM-1 上，从而阻止了 ICAM-1 黏附体的形成并损害了白细胞的铺展。这可以通过过表达 DLC-1 来挽救，导致 ICAM-1 黏附体的稳定和白细胞的铺展。我们的结果揭示了内皮细胞 DLC-1 受基质硬度调节的重要作用，独立于其 GAP 结构域，可局部稳定 ICAM-1 黏附体，促进白细胞铺展，这对于有效的白细胞跨内皮迁移是必需的。
