Regulation of bovine brain microvascular endothelial tight junction assembly and barrier function by laminar shear stress
Regulation of bovine brain microvascular endothelial tight junction assembly and barrier function by laminar shear stress
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DOI：
10.1152/ajpheart.01177.2006
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发表时间：
2007-06-01
影响因子：
4.8
通讯作者：
Cummins, Philip M.
中科院分区：
文献类型：
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作者：
Colgan, Olga C.;Ferguson, Gail;Cummins, Philip M.
血脑屏障(BBB)控制细胞旁溶质向脑微环境的扩散，并主要通过相邻微血管内皮细胞之间的紧密连接来维持。尽管缺乏详细的生化数据，但研究表明血流相关切应力是血脑屏障功能的病理生理学中介。我们假设，剪切力通过直接调节关键紧密连接蛋白occludin和zonula occludens-1(ZO-1)的表达和性质来上调BBB功能。将牛脑微血管内皮细胞(BBMvECs)暴露于10和14dyn/cm2的恒定剪切力和14dyn/cm2的脉动剪切力中24 h，观察剪切后BBMvECs occludin-ZO-1的表达、结合和亚细胞定位，并检测BBMvECs对FITC-葡聚糖和(14)[C]蔗糖的跨内皮通透性。恒定剪切力作用24 h后，肌动蛋白重组和BBMvEC重排，rnRNA和蛋白表达显著增加(2.73+/-0.26倍和1.83+/-0.03倍)，与ZO-1结合显著增加(2.12+/-0.15倍)。随着FITC-葡聚糖(但不是蔗糖)对FITC-葡聚糖(但不是蔗糖)的跨内皮渗透性降低，稳定的剪切力也导致这两种蛋白质明显地重新定位到细胞-细胞边界。在脉动切应力作用下，随着对(14)[C]蔗糖跨内皮通透性的降低，occludin和ZO-1的蛋白水平(2.15+/-0.02和1.67+/-0.21倍)和occludin-ZO-1结合的增加(2.91+/-0.14倍)被观察到。剪切力通过调节occludin和ZO-1的表达、结合和定位，在分子水平上调BBMvEC屏障功能。脉动切变模型似乎给出了最深刻的生化反应。
Blood-brain barrier (BBB) controls paracellular solute diffusion into the brain microenvironment and is maintained primarily by tight junctions between adjacent microvascular endothelial cells. Studies implicate blood flow-associated shear stress as a pathophysiological mediator of BBB function, although detailed biochemical data are scarce. We hypothesize that shear stress upregulates BBB function via direct modulation of expression and properties of pivotal tight-junction proteins occludin and zonula occludens-1 (ZO-1). Bovine brain microvascular endothelial cells (BBMvECs) were exposed to either steady or Pulsatile shear stress (10 and 14 dyn/cm(2) 2, respectively) for 24 h. Sheared BBMvECs were monitored for occludin-ZO-1 expression, association, and subcellular localization, and transendothelial permeability of BBMvECs to FITC-dextran and (14)[C]sucrose was assessed. Actin reorganization and BBMvEC realignment were observed following steady shear stress for 24 h. Substantial increases in occludin rnRNA and protein expression (2.73 +/- 0.26- and 1.83 +/- 0.03-fold) and in occludin-ZO-1 association (2.12 +/- 0.15-fold) were also observed. Steady shear stress also induced clear relocalization of both proteins to the cell-cell border in parallel with reduced transendothelial permeability to FITC-dextran (but not Sucrose). Following pulsatile shear stress, increased protein levels for both occludin and ZO-1 (2.15 +/- 0.02- and 1.67 +/- 0.21-fold) and increased occludin-ZO-1 association (2.91 +/- 0.14-fold) were observed in parallel with a reduction in transendothelial permeability to (14)[C]sucrose. Shear stress upregulates BBMvEC barrier function at the molecular level via modulation of expression, association, and localization of occludin and ZO-1. The pulsatile shear model appeared to give the most profound biochemical responses.