Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX 77030, USA.
Am J Physiol Cell Physiol. 2010 Jun;298(6):C1583-93. doi: 10.1152/ajpcell.00458.2009. Epub 2010 Feb 17.
Hypoxia-induced disruption of the blood-brain barrier (BBB) is the result of many different mechanisms, including alterations to the cytoskeleton. In this study, we identified actin-binding proteins involved in cytoskeletal dynamics with quantitative proteomics and assessed changes in subcellular localization of two proteins involved in actin polymerization [vasodilator-stimulated phosphoprotein (VASP)] and cytoskeleton-plasma membrane cross-linking (moesin). We found significant redistribution of both VASP and moesin to the cytoskeletal and membrane fractions of BBB endothelial cells after 1-h hypoxic stress. We also investigated activation of actin-myosin contraction through assessment of phosphorylated myosin light chain (pMLC) with confocal microscopy. Hypoxia caused a rapid and transient increase in pMLC. Blocking MLC phosphorylation through inhibition of myosin light chain kinase (MLCK) with ML-7 prevented hypoxia-induced BBB disruption and relocalization of the tight junction protein ZO-1. Finally, we implicate the transient receptor potential (TRP)C family of channels in mediating these events since blockade of TRPC channels and the associated calcium influx with SKF-96365 prevents hypoxia-induced permeability changes and the phosphorylation of MLC needed for actin-myosin contraction. These data suggest that hypoxic stress triggers alterations to cytoskeletal structure that contribute to BBB disruption and that calcium influx through TRPC channels contributes to these events.
缺氧诱导的血脑屏障(BBB)破坏是许多不同机制的结果,包括细胞骨架的改变。在这项研究中,我们使用定量蛋白质组学鉴定了参与细胞骨架动力学的肌动蛋白结合蛋白,并评估了两种参与肌动蛋白聚合的蛋白质(血管扩张刺激磷蛋白(VASP))和细胞骨架-质膜交联(膜突蛋白))的亚细胞定位变化。我们发现,缺氧应激 1 小时后,VASP 和 moesin 两种蛋白均显著重新分布到 BBB 内皮细胞的细胞骨架和膜部分。我们还通过共聚焦显微镜评估磷酸化肌球蛋白轻链(pMLC)来研究肌动球蛋白收缩的激活。缺氧导致 pMLC 迅速短暂增加。通过用 ML-7 抑制肌球蛋白轻链激酶(MLCK)抑制 MLC 磷酸化可防止缺氧引起的 BBB 破坏和紧密连接蛋白 ZO-1 的重新定位。最后,我们暗示瞬时受体电位(TRP)C 家族通道在介导这些事件中起作用,因为阻断 TRPC 通道和相关的钙内流用 SKF-96365 可防止缺氧引起的通透性变化和肌动球蛋白收缩所需的 MLC 磷酸化。这些数据表明,缺氧应激触发细胞骨架结构的改变,导致 BBB 破坏,而通过 TRPC 通道的钙内流有助于这些事件。