Mechanisms of modulation of brain microvascular endothelial cells function by thrombin.
Mechanisms of modulation of brain microvascular endothelial cells function by thrombin.
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DOI：
10.1016/j.brainres.2016.12.011
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发表时间：
2017-02-15
期刊：
影响因子：
2.9
通讯作者：
Brailoiu GC
中科院分区：
文献类型：
--
作者：
Brailoiu E;Shipsky MM;Yan G;Abood ME;Brailoiu GC
脑微血管内皮细胞是血脑屏障的重要组成部分。它们形成一个紧密的单层，这对维持大脑的稳态至关重要。血液来源的蛋白酶如凝血酶可在病理状况如创伤、中风和炎症期间进入脑，并通过不完全表征的机制进一步破坏血脑屏障的渗透性。我们研究了凝血酶在大鼠脑微血管内皮细胞（RBMVEC）中引起的潜在机制。我们的研究结果表明，凝血酶，作用于蛋白酶激活受体1（PAR 1）增加细胞内Ca 2+浓度RBMVEC通过Ca 2+释放内质网通过肌醇1，4，5-三磷酸受体和Ca 2+内流从细胞外空间。凝血酶可增加一氧化氮的产生;抑制一氧化氮合酶或拮抗PAR 1受体可消除这种作用。此外，凝血酶通过PAR 1依赖性机制增加线粒体和胞质活性氧的产生。免疫细胞化学研究表明，凝血酶增加F-肌动蛋白应力纤维，并破坏紧密连接。凝血酶增加RBMVEC渗透性通过荧光通量测定评估。总之，我们的研究结果表明凝血酶调节RBMVEC功能的多种机制，并可能导致血脑屏障功能障碍。
Brain microvascular endothelial cells are a critical component of the blood-brain barrier. They form a tight monolayer which is essential for maintaining the brain homeostasis. Blood-derived proteases such as thrombin may enter the brain during pathological conditions like trauma, stroke, and inflammation and further disrupts the permeability of the blood-brain barrier, via incompletely characterized mechanisms. We examined the underlying mechanisms evoked by thrombin in rat brain microvascular endothelial cells (RBMVEC). Our results indicate that thrombin, acting on protease-activated receptor 1 (PAR1) increases cytosolic Ca2+ concentration in RBMVEC via Ca2+ release from endoplasmic reticulum through inositol 1,4,5-trisphosphate receptors and Ca2+ influx from extracellular space. Thrombin increases nitric oxide production; the effect is abolished by inhibition of the nitric oxide synthase or by antagonism of PAR1 receptors. In addition, thrombin increases mitochondrial and cytosolic reactive oxygen species production via PAR1-dependent mechanisms. Immunocytochemistry studies indicate that thrombin increases F-actin stress fibers, and disrupts the tight junctions. Thrombin increased the RBMVEC permeability assessed by a fluorescent flux assay. Taken together, our results indicate multiple mechanisms by which thrombin modulates the function of RBMVEC and may contribute to the blood-brain barrier dysfunction.