Adropin reduces paracellular permeability of rat brain endothelial cells exposed to ischemia-like conditions
Adropin reduces paracellular permeability of rat brain endothelial cells exposed to ischemia-like conditions
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DOI：
10.1016/j.peptides.2016.03.009
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发表时间：
2016-07-01
期刊：
影响因子：
3
通讯作者：
Candelario-Jalil, Eduardo
中科院分区：
文献类型：
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作者：
Yang, Changjun;DeMars, Kelly M.;Candelario-Jalil, Eduardo
Adropin是一种由能量稳态相关基因（Enho）编码的肽，在脂质代谢、胰岛素敏感性和内皮功能的调节中起关键作用。关于adropin在脑中的作用以及这种肽是否调节缺血诱导的血脑屏障（BBB）损伤，我们知之甚少。本研究采用大鼠脑微血管内皮细胞（RBE4）体外血脑屏障模型，并假设adropin会降低缺血状态下内皮细胞的通透性。为了模拟体外缺血情况，RBE4细胞单层受到16h缺氧/低糖（HLG）的影响。这导致细胞旁对fitc标记的葡聚糖的通透性显著增加（40 kDa），血管内皮生长因子（VEGF）显著上调，以及连接蛋白occludin和VE-cadherin的缺失。值得注意的是，HLG也显著降低了Enho表达和adpin水平。用合成adropin（1、10和100 ng/ml）浓度依赖性地处理RBE4细胞可降低HLG后内皮细胞的通透性，但这不是通过保护连接蛋白或降低VEGF水平来介导的。我们发现，HLG显著增加了RBE4细胞中肌球蛋白轻链2 （MLC2）的磷酸化，而adropin处理显著降低了这一磷酸化。我们还发现，HLG显著增加了rho相关激酶（ROCK）的活性，这是MLC2磷酸化的关键上游效应物，而adropin处理减弱了这种作用。这些数据表明，adropin通过抑制ROCK-MLC2信号通路降低HLG损伤后内皮细胞的通透性。这些有希望的发现表明，adropin可以防止缺血条件下内皮屏障功能障碍。(C) 2016 Elsevier Inc.版权所有。
Adropin is a peptide encoded by the energy homeostasis associated gene (Enho) and plays a critical role in the regulation of lipid metabolism, insulin sensitivity, and endothelial function. Little is known of the effects of adropin in the brain and whether this peptide modulates ischemia-induced blood-brain barrier (BBB) injury. Here, we used an in vitro BBB model of rat brain microvascular endothelial cells (RBE4) and hypothesized that adropin would reduce endothelial permeability during ischemic conditions. To mimic ischemic conditions in vitro, RBE4 cell monolayers were subjected to 16h hypoxia/low glucose (HLG). This resulted in a significant increase in paracellular permeability to FITC-labeled dextran (40 kDa), a dramatic upregulation of vascular endothelial growth factor (VEGF), and the loss of junction proteins occludin and VE-cadherin. Notably, HLG also significantly decreased Enho expression and adropin levels. Treatment of RBE4 cells with synthetic adropin (1,10 and 100 ng/ml) concentration-dependently reduced endothelial permeability after HLG, but this was not mediated through protection to junction proteins or through reduced levels of VEGF. We found that HLG dramatically increased myosin light chain 2 (MLC2) phosphorylation in RBE4 cells, which was significantly reduced by adropin treatment. We also found that HLG significantly increased Rho-associated kinase (ROCK) activity, a critical upstream effector of MLC2 phosphorylation, and that adropin treatment attenuated that effect. These data indicate that treatment with adropin reduces endothelial cell permeability after HLG insult by inhibition of the ROCK-MLC2 signaling pathway. These promising findings suggest that adropin protects against endothelial barrier dysfunction during ischemic conditions. (C) 2016 Elsevier Inc. All rights reserved.