Vestweber Dietmar, Wessel Florian, Nottebaum Astrid Fee
Max-Planck-Institute for Molecular Biomedicine, Röntgenstr. 20, D-48149, Münster, Germany,
Semin Immunopathol. 2014 Mar;36(2):177-92. doi: 10.1007/s00281-014-0419-7. Epub 2014 Mar 18.
Leukocyte extravasation is regulated and mediated by a multitude of adhesion and signaling molecules. Many of them enable the capturing and docking of leukocytes to the vessel wall. Others allow leukocytes to crawl on the apical surface of endothelial cells to appropriate sites of exit. While these steps are well understood and the adhesion molecules mediating these interactions are largely identified, a still growing number of adhesion receptors mediate the diapedesis process, the actual migration of leukocytes through the endothelial cell layer, and the underlying basement membrane. In most cases, it is not known which molecular processes they actually mediate, whether they enable the migration of leukocytes through the endothelial cell layer or whether they are involved in the destabilization of endothelial junctions. In addition, leukocytes are able to circumvent junctions and transcytose directly through the body of endothelial cells. While this latter route indeed exists, recent work has highlighted in vivo the junctional pathway as the prevalent way of leukocyte exit in various inflamed tissues. Recent work elucidating molecular mechanisms that regulate endothelial junctions and thereby leukocyte extravasation and vascular permeability will be discussed.
白细胞渗出由多种黏附分子和信号分子调控与介导。其中许多分子使白细胞能够捕获并附着于血管壁。其他分子则允许白细胞在内皮细胞的顶端表面爬行至合适的穿出位点。虽然这些步骤已被充分理解，介导这些相互作用的黏附分子也大多已被确定，但仍有越来越多的黏附受体介导白细胞渗出过程，即白细胞实际穿过内皮细胞层和下方基底膜的迁移过程。在大多数情况下，尚不清楚它们实际介导哪些分子过程，它们是否能使白细胞穿过内皮细胞层，或者它们是否参与内皮连接的不稳定。此外，白细胞能够绕过连接并直接通过内皮细胞体进行跨细胞转运。虽然后一种途径确实存在，但最近的研究在体内突出了连接途径是各种炎症组织中白细胞渗出的主要方式。本文将讨论阐明调节内皮连接从而调控白细胞渗出和血管通透性的分子机制的最新研究。
