1 Division of Hematology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
2 Department of Neurology, Keio University School of Medicine, Tokyo, Japan.
J Cereb Blood Flow Metab. 2018 Apr;38(4):641-658. doi: 10.1177/0271678X17722108. Epub 2017 Aug 8.
Acutely following focal cerebral ischemia disruption of the microvessel blood-brain barrier allows transit of plasma proteins into the neuropil as edema formation that coincides with loss of microvessel endothelial β1-integrins. We extend previous findings to show that interference with endothelial β1-integrin-matrix adhesion by the monoclonal IgM Ha2/5 increases the permeability of primary cerebral microvascular endothelial cell monolayers through reorganization of claudin-5, occludin, and zonula occludens-1 (ZO-1) from inter-endothelial borders. Interference with β1-integrin-matrix adhesion initiates F-actin conformational changes that coincide with claudin-5 redistribution. β1-integrin-matrix interference simultaneously increases phosphorylation of myosin light chain (MLC), while inhibition of MLC kinase (MLCK) and Rho kinase (ROCK) abolishes the Ha2/5-dependent increased endothelial permeability by 6 h after β1-integrin-matrix interference. These observations are supported by concordant observations in the cortex of a high-quality murine conditional β1-integrin deletion construct. Together they support the hypothesis that detachment of β1-integrins from abluminal matrix ligands increases vascular endothelial permeability through reorganization of tight junction (TJ) proteins via altered F-actin conformation, and indicate that the β1-integrin-MLC signaling pathway is engaged when β1-integrin detachment occurs. These findings provide a novel approach to the research and treatment of cerebral disorders where the breakdown of the blood-brain barrier accounts for their progression and complication.
急性局灶性脑缺血后，微血管血脑屏障破坏，允许血浆蛋白通过水肿形成进入神经原，这与微血管内皮细胞β1 整联蛋白的丧失一致。我们扩展了以前的发现，表明通过单克隆 IgM Ha2/5 干扰内皮细胞β1 整联蛋白-基质黏附，通过 Claudin-5、occludin 和 zonula occludens-1（ZO-1）从内皮边界的重排增加原代大脑微血管内皮细胞单层的通透性。干扰β1 整联蛋白-基质黏附会引发 F-actin 构象变化，同时伴随着 Claudin-5 的重新分布。β1 整联蛋白-基质干扰同时增加肌球蛋白轻链（MLC）的磷酸化，而肌球蛋白轻链激酶（MLCK）和 Rho 激酶（ROCK）的抑制作用在β1 整联蛋白-基质干扰后 6 小时内通过 Claudin-5 依赖性增加内皮通透性。这些观察结果得到了高质量鼠条件性β1 整联蛋白缺失构建体皮质中一致观察结果的支持。综上所述，这些结果支持这样一种假设，即β1 整联蛋白从基底外侧基质配体上的脱离通过改变 F-actin 构象重新组织紧密连接（TJ）蛋白来增加血管内皮通透性，并表明当β1 整联蛋白脱离时，β1 整联蛋白-MLC 信号通路被激活。这些发现为研究和治疗脑障碍提供了一种新方法，其中血脑屏障的破坏是其进展和并发症的原因。
