Bradykinin increases blood-tumor barrier permeability by down-regulating the expression levels of ZO-1, occludin, and claudin-5 and rearranging actin cytoskeleton
Bradykinin increases blood-tumor barrier permeability by down-regulating the expression levels of ZO-1, occludin, and claudin-5 and rearranging actin cytoskeleton
复制标题
缓激肽通过下调 ZO-1、occludin 和 claudin-5 的表达水平并重新排列肌动蛋白细胞骨架来增加血液肿瘤屏障通透性
DOI：
10.1002/jnr.21558
复制
发表时间：
2008-04-01
影响因子：
4.2
通讯作者：
Wang, Yi-bao
中科院分区：
文献类型：
--
作者：
Liu, Li-bo;Xue, Yi-xue;Wang, Yi-bao
缓激肽（BK）可选择性地开放血肿瘤屏障（BTB），并可瞬时增加BTB的通透性，但其作用机制尚不清楚。进行本研究以确定BK是否通过影响紧密连接（TJ）相关蛋白质闭锁小带-1（ZO-1）、闭锁蛋白和caludin-5以及细胞骨架蛋白丝状肌动蛋白（F-actin）来打开BTB。在大鼠脑胶质瘤模型和体外BTB模型中，我们发现BK诱导可降低ZO-1、occludin和claudin-5的蛋白表达水平。免疫组织化学和免疫荧光分析表明，ZO-1，occludin，和claudin-5和F-actin的减弱表达是最明显的较小的肿瘤毛细血管（20 μ m）。同时观察到ZO-1、occludin和claudin-5在脑微血管内皮细胞中的重新分布以及F-actin的重排。伊文思蓝法显示BK灌注后BTB的通透性增加。透射电子显微镜显示TJ被打开，胞饮泡密度增加。跨内皮电阻（TEER）和辣根过氧化物酶通量测定也表明TJ被BK诱导打开。放射免疫和蛋白质印迹分析显示肿瘤组织中cAMP和蛋白激酶A催化亚基（PKAcs）的表达水平显著降低。本研究表明BK介导的BTB通透性增加与ZO-1、claudin-5的下调及F-actin的重排有关，cAMP/PKA信号转导系统可能参与了这一调节过程。(C)2008 Wiley-Liss，Inc.
Bradykinin (BK) has been shown to open blood-tumor barrier (BTB) selectively and to increase permeability of the BTB transiently, but the mechanism is unclear. This study was performed to determine whether BK opens the BTB by affecting the tight junction (TJ)-associated proteins zonula occluden-1 (ZO-1), occludin, and caludin-5 and cytoskeleton protein filamentous actin (F-actin). In rat brain glioma model and BTB model in vitro, we find that the protein expression levels of ZO-1, occludin, and claudin-5 are attenuated by BK induction. Immunohistochemistry and immunofluorescence assays show that the attenuated expression of ZO-1, occludin, and claudin-5 and F-actin is most obvious in the smaller tumor capillaries (20 mu m). The redistribution of ZO-1, occludin, and claudin-5 and rearrangement of F-actin in brain microvascular endothelial cells are observed at the same time. Meanwhile, Evans blue assay shows that the permeability of BTB increases after BK infusion. Transmission electron microscopy indicates that TJ is opened and that pinocytotic vesicular density is increased. Transendothelial electrical resistance (TEER) and horseradish peroxidase flux assays also reveal that TJ is opened by BK induction. In addition, radioimmunity and Western blot assay reveal a significant decrease in expression levels of cAMP and catalytic subunit of protein kinase A (PKAcs) of tumor tissue. This study demonstrates that the increase of BK-mediated BTB permeability is associated with the down-regulation of ZO-1 occludin, and claudin-5 and the rearrangement of F-actin and that cAMP/PKA signal transduction system might be involved in the modulating process. (C) 2008 Wiley-Liss, Inc.