Barrier dysfunction and RhoA activation are blunted by homocysteine and adenosine in pulmonary endothelium
Barrier dysfunction and RhoA activation are blunted by homocysteine and adenosine in pulmonary endothelium
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DOI：
10.1152/ajplung.00421.2003
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发表时间：
2004-12-01
影响因子：
4.9
通讯作者：
Rounds, S
中科院分区：
文献类型：
--
作者：
Harrington, EO;Newton, J;Rounds, S
RhoA GTP酶调节内皮通透性。我们以前已经表明，腺苷和同型半胱氨酸增强肺动脉内皮细胞的基础屏障功能的机制，涉及减少RhoA羧基甲基化和活性。在目前的研究中，我们研究了腺苷和同型半胱氨酸对培养的单层内皮细胞单层通透性的影响。腺苷和同型半胱氨酸显着减弱凝血酶诱导的内皮屏障功能障碍和细胞间隙形成。我们发现，与载体处理的内皮细胞相比，腺苷和同型半胱氨酸预处理的内皮细胞中与膜亚细胞组分相关的RhoA显著减少。此外，腺苷和同型半胱氨酸显着钝化凝血酶暴露后RhoA激活。腺苷和同型半胱氨酸孵育也增强了RhoA和RhoGDI之间的体外相互作用，以及p190RhoGAP向胞质溶胶的亚细胞易位。这些数据表明，升高的细胞内浓度的同型半胱氨酸和腺苷增强从主肺动脉和肺微血管系统分离的培养的内皮细胞中的内皮屏障功能，表明对肺损伤响应的肺水肿的潜在保护作用。我们推测同型半胱氨酸和腺苷通过调节RhoA翻译后加工调节内皮屏障功能障碍的水平，通过改变与RhoA激活调节剂的相互作用导致GTdR活性降低。
RhoA GTPases modulate endothelial permeability. We have previously shown that adenosine and homocysteine enhance basal barrier function in pulmonary artery endothelial cells by a mechanism involving diminution of RhoA carboxyl methylation and activity. In the current study, we investigated the effects of adenosine and homocysteine on endothelial monolayer permeability in cultured monolayers. Adenosine and homocysteine significantly attenuated thrombin-induced endothelial barrier dysfunction and intercellular gap formation. We found significantly diminished RhoA associated with the membrane subcellular fraction in endothelial cells pretreated with adenosine and homocysteine, compared with vehicle-treated endothelial cells. Additionally, adenosine and homocysteine significantly blunted RhoA activation following thrombin exposure. Incubation with adenosine and homocysteine also enhanced in vitro interactions between RhoA and RhoGDI, as well as subcellular translocation of p190RhoGAP to the cytosol. These data demonstrate that elevated intracellular concentrations of homocysteine and adenosine enhance endothelial barrier function in cultured endothelial cells isolated from the main pulmonary artery and lung microvasculature, suggesting a potentially protective effect against pulmonary edema in response to lung injury. We speculate that homocysteine and adenosine modulate the level of endothelial barrier dysfunction through modulation of RhoA posttranslational processing resulting in diminished GTPase activity through altered interactions with modulators of RhoA activation.