The study of endothelial cell signal transduction during neutrophil transmigration

中性粒细胞的跨内皮细胞迁移是急性炎症的关键步骤，我们先前的研究表明，它受内皮细胞肌球蛋白轻链激酶的调节。最近的研究表明，Rho和Rho激酶也是肌球蛋白轻链(MLC)磷酸化的关键介质，但它们在中性粒细胞迁移中的作用尚未被研究。本研究采用含内皮单分子层的跨孔室迁移实验系统，在体外检测了中性粒细胞迁移过程中不同时间内皮细胞F-肌动蛋白和肌球蛋白II重排以及内皮细胞MLC的磷酸化。结果显示，用C3(Rho抑制剂)或Y-27632(Rho激酶抑制剂)处理内皮细胞后，中性粒细胞的迁移、肌动蛋白聚合、肌球蛋白II丝的形成以及正常情况下与迁移相关的MLC的磷酸化均显著减少。这些数据表明，内皮Rho和Rho激酶通过调节介导中性粒细胞跨内皮中性粒细胞迁移的细胞骨架事件来调节这种迁移。

The transendothelial migration of neutrophils is a critical step in acute inflammation, which we previously showed to be regulated by endothelial myosin light chain kinase. Recent studies suggest that Rho and Rho kinase are also key mediators of myosin light chain (MLC) phosphorylation, but their roles in neutrophil migration has not been investigated. In the present study, a transwell chamber migration assay system incorporating endothelial monolayer was used to examined the numbers of migrating neutrophils, endothelial F-actin and myosin II rearrangement and endothelial MLC phosphorylation at selected times during the neutrophil migration, in vitro. The results showed that pretreating endothelial cells with C3 (Rho inhibitor) or Y-27632 (Rho kinase inhibitor) significantly diminished neutrophil migration, actin polymerization, myosin II filament formation and MLC phosphorylation normally associated with the migration. These data suggest that endothelial Rho and Rho kinase regulate transendothelial neutrophil migration by modulating the cytoskeletal events that mediate such migration.