Regulation of NADPH Oxidase by Phospholipase D and the EC Cytoskeleton

机械应力可导致肺内皮细胞(EC)屏障受损 与呼吸机诱导的肺损伤(VILI)相关，这一过程导致血管通透性增加， 肺泡泛滥，白细胞渗透，低氧血症，发病率和死亡率增加。项目#3 科学家此前已经确定了通过屏障保护来调节EC屏障的细胞骨架机制 策略(氧化型磷胆碱、1-磷酸鞘氨醇、生理性切应力和循环拉伸 (CS)和破坏屏障的机械和化学刺激(凝血酶、病理性CS)。此外，这些 PPG研究人员描述了小GTP酶Rac和Rho在血管重构中的关键参与 EC细胞骨架和细胞接触对EC屏障调节至关重要。我们公布的结果和初步结果 数据有力地表明，CS对Rac和Rho活动的调节具有明显的幅度依赖性 影响激动剂诱导的内皮细胞通透性变化。项目3的假设是病理性CS和 已知在VILI期间升高的血管内皮生长因子(VEGF)促进肺内皮细胞 通过对Rho通路介导的EC通透性的协同作用来实现屏障功能障碍。这些过程是 由肝细胞等屏障保护性刺激诱导的RAC依赖机制平衡 生长因子(HGF)与生理拉伸。我们推测局灶性粘连可能作为机械感受器。 并通过与RAC和Rho蛋白调节因子的特异性Paxlin相互作用来调节小GTP酶的活性。 特定目标#1将研究病理性CS和血管内皮细胞生长因子对罗美地特激活的协同作用 EC屏障功能障碍。具体目标#2将定义障碍保护战略，以改善 VILI相关的EC屏障功能障碍是通过改变Rho和Rac活动之间的平衡来实现的。 具体目标#3将研究机械力化学因素通过以下途径调节RAC/RHO的新机制 野生型杆菌素(或/和含有Gly73Ser多态的杆菌素)相互作用 带有RAC和Rho活性调节剂(GIT2、BetaPIX、PAK1和p190RhoGAP)。这些研究将 揭示呼吸机所致肺损伤发病机制及解决的新分子机制 受伤。

Compromise of the pulmonary endothelial cell (EC) barrier is induced by mechanical stress which is associated with ventilator-induced lung injury (VILI), This process leads to increased vascular permeability, alveolar flooding, leukocyte infiltration, hypoxemia, and increased morbidity and mortality. Project #3 scientists have previously identified cytoskeletal mechanisms of EC barrier regulation by barrier-protective strategies (oxidized phosphocholine, sphingosine 1-phosphate, physiologic shear stress and cyclic stretch (CS) and barrier-disruptive mechanical and chemical stimuli (thrombin, pathologic CS). In addition, these PPG investigator have described the critical involvement of small GTPases Rac and Rho in remodeling of EC cytoskeleton and cell contacts essential for EC barrier regulation. Our published results and preliminary data strongly suggest that magnitude-dependent modulation of Rac and Rho activities by CS significantly impacts agonist-induced EC permeability changes. The Project #3 hypothesis is that pathologic CS and vascular endothelial growth factor (VEGF), known to be elevated during VILI, promote lung endothelial barrier dysfunction via synergistic effects on Rho pathway-mediated EC permeability. These processes are counterbalanced by Rac-dependent mechanisms induced by barrier-protective stimuli such as hepatocyte growth factor (HGF) and physiologic stretch. We speculate that focal adhesions may act as mechanosensors and modulate small GTPase activities via specific paxillin interactions with Rac and Rho protein regulators. Specific Aim #1 will study synergistic effects between pathologic CS and VEGF on activation of Rhomediated EC barrier dysfunction. Specific Aim #2 will define barrier-protective strategies in amelioration of VILI-associated EC barrier dysfunction via changes in a balance between the Rho and Rac activities. Specific Aim #3 will study novel mechanisms of Rac/Rho regulation by mechanochemical factors via interactions between wild type paxillin (or/and paxillin containing the Gly73Ser polymorphism) interactions with modulators of Rac and Rho activity (GIT2, betaPIX, PAK1 and p190RhoGAP). These studies will uncover novel molecular mechanisms involved in the pathogenesis and resolution of ventilator-induced lung injury.