Role of Protein Nitration In Altering The Rho/Rac1 Balance In Acute Lung Injury

项目SuIVIMARY(请参阅说明)： 血管内皮细胞的一个重要功能是在血液和周围组织之间提供选择性屏障。在急性肺损伤(ALI)的发展过程中，内皮屏障被削弱，导致通透性增加。众所周知，小分子ras同源(Rho)GTP酶家族(RhoA、Rad、CDC42)在维持内皮屏障特性中起着至关重要的作用。Rho GTP酶的两个最具代表性的成员：Rho A和Rad，似乎以一种拮抗的方式调节内皮屏障功能。因此，Rho A的激活损害了屏障功能，而Rad似乎支持屏障的完整性。此外，我们最近的研究表明，在小鼠ALI的发生发展过程中，RhoA和Rad的活性受到相反的调节，导致RhoA活性增加，Rad活性减弱。加在一起，这些变化将有利于障碍的打破。然而，这种相反的调控发生的机制尚未解决，这是该项目的主要焦点。我们将评估解偶联eNOS通过硝化介导的修饰导致RhoA/Rad平衡调节的机制。我们还将确定，在体外，防止RhoA和Rad硝化是否具有屏障保护作用，并在体内减少G‘和G^-鼠ALI模型的肺损伤。预计该项目使用最先进的细胞、分子、生化和生理学方法，不仅将增加我们对G(-)和G(+)诱导的ALI期间RhoA和Rad被调节的机制的了解，而且将促进开发新的战略和目标来治疗这种40年来死亡率没有显著下降的疾病。

PROJECT SUIVIMARY (See instructions): An important function of the endothelium lining the inner surface of blood vessels is to provide a selective barrier between blood and the surrounding tissues. During the development of acute lung injury (ALI) the endothelial barrier is weakened, leading to increased permeability. It is well known that the family of small ras homology (Rho) GTPases (RhoA, Rad, Cdc42) play a crucial role in the maintenance of endothelial barrier properties. The two best-characterized members of the Rho GTPases: Rho A and Rad, appear to regulate endothelial barrier function in an antagonistic manner. Thus, the activation of Rho A impairs barrier function whereas Rad appears to support barrier integrity. In addition, our recent studies have shown that during the development of ALI in the mouse lung the activities of RhoA and Rad are regulated in an opposing manner such that RhoA activity is increased and Rad activity is attenuated. Together these changes would favor barrier disruption. However, the mechanism by which this opposing regulation occurs unresolved and is the major focus of this project. We will evaluate the mechanisms by which uncoupled eNOS leads to modulation of RhoA/Rad balance through nitration-mediated modifications. We will also determine if preventing RhoA and Rad nitration is barrier protective in vitro and reduces lung injury in both G' and G^-mouse models of ALI, in vivo. It is anticipated that this Project using state-of-the-art cellular, molecular, biochemical, and physiological approaches that will not only increase our understanding of the mechanisms by which RhoA and Rad are regulated during both G(-)- and G(+) -induced ALI but will facilitate the development of new strategies and targets for the treatment of a disease that has not seen a significant drop in mortality in 40 years.