VEGF-mediated disruption of endothelial CLN-5 promotes blood-brain barrier breakdown
VEGF-mediated disruption of endothelial CLN-5 promotes blood-brain barrier breakdown
复制标题
DOI：
10.1073/pnas.0808698106
复制
发表时间：
2009-02-10
影响因子：
11.1
通讯作者：
John, Gareth R.
中科院分区：
文献类型：
--
作者：
Argaw, Azeb Tadesse;Gurfein, Blake T.;John, Gareth R.
血脑屏障(BBB)的破坏是中枢神经系统炎症的早期和重要事件。星形胶质细胞来源的血管内皮生长因子-A参与了这一反应，但其潜在的机制仍未解决。在这里，我们确定内皮细胞跨膜紧密连接蛋白claudin-5(cln-5)和occludin(OCLN)是血管内皮生长因子-A作用的靶点。在中枢神经系统炎症性疾病的动物模型--实验性自身免疫性脑脊髓炎中，CLN-5和OCLN的下调伴随着VEGF-A的上调，并与血脑屏障的破坏有关。在培养的脑微血管内皮细胞中，VEGF-A特异性下调CLN-5和OCLN蛋白和mRNA的表达。在小鼠大脑皮层，微量注射血管内皮生长因子-A可破坏CLN-5和OCLN，导致屏障功能丧失。重要的是，功能研究表明，表达重组CLN-5可以保护培养的脑微血管内皮细胞免受血管内皮生长因子诱导的细胞旁通透性增加的影响，而在相同启动子下表达的重组OCLN不具有保护作用。先前的研究表明，CLN-5是血脑屏障跨内皮细胞抵抗的关键决定因素。我们的发现表明，其下调的血管内皮生长因子-A构成了一个重要的机制，在血脑屏障的破坏。
Breakdown of the blood-brain barrier (BBB) is an early and significant event in CNS inflammation. Astrocyte-derived VEGF-A has been implicated in this response, but the underlying mechanisms remain unresolved. Here, we identify the endothelial transmembrane tight junction proteins claudin-5 (CLN-5) and occludin (OCLN) as targets of VEGF-A action. Down-regulation of CLN-5 and OCLN accompanied up-regulation of VEGF-A and correlated with BBB breakdown in experimental autoimmune encephalomyelitis, an animal model of CNS inflammatory disease. In cultures of brain microvascular endothelial cells, VEGF-A specifically down-regulated CLN-5 and OCLN protein and mRNA. In mouse cerebral cortex, microinjection of VEGF-A disrupted CLN-5 and OCLN and induced loss of barrier function. Importantly, functional studies revealed that expression of recombinant CLN-5 protected brain microvascular endothelial cell cultures from a VEGF-induced increase in paracellular permeability, whereas recombinant OCLN expressed under the same promoter was not protective. Previous studies have shown CLN-5 to be a key determinant of trans-endothelial resistance at the BBB. Our findings suggest that its down-regulation by VEGF-A constitutes a significant mechanism in BBB breakdown.