; Subjects diagnosed with ARDS exhibit ~40% mortality, thus demanding fresh approaches to the management of this serious condition. This Project will investigate a totally new mechanism of both G+ and G- bacteria-induced endothelial barrier dysfunction in human endothelial cells and in ALI/ARDS. It follows the studies on the crucial role RhoA/Rac1 imbalance in endothelial barrier dysfunction and ALI/ARSD, proposed in Project 1. Here we focus on the activation of endothelial RhoA that produces endothelial hyperpermeability in culture and increased pulmonary capillary permeability, in vivo. We propose a novel mechanism of regulating RhoA activity that could be useful in the management of ALI and ARDS. Preliminary data from Project 1 and published studies suggest that pp60src is a key step in RhoA activation, which leads to the phosphorylation of the small heat shock protein 27 (hsp27), a major cause of F-actin stress fiber formation and endothelial barrier dysfunction. The kinase, ppGOsrc is a well-known heat shock protein 90 (hsp90) client protein and we recently published that hsp27 co-immunoprecipitates with hsp90. Preliminary data suggest that the hsp90 inhibitor, 17-/ AG reduces both LPS-induced ppSOsrc activation and hsp27 phosphorylation, as well as LPS-induced RhoA activation, in endothelial cells. Furthermore, we have recently demonstrated that hsp90 inhibition prevents and reverses LPS-induced endothelial barrier dysfunction, in culture, and reduces capillary hyper-permeability, inflammation, lung dysfunction and mortality in a mouse model of LPS-induced ALI. Still, the effects of hsp90-mediated regulation of ppBOsrc, RhoA and hsp27 activation on G+ and G- induced endothelial barrier dysfunction, especially human endothelial cell barrier function, and in the management of ALI, in vivo, remain unknown. This project will test the hypothesis that hsp90 is an important regulator of human endothelial cell hyper-permeability, in vitro, and of ALI, in vivo. We will further test the hypothesis that hsp90 exerts these actions, in part, by controlling the fate of two key proteins (ppSOsrc, hsp27) that are involved in RhoA activation and signal transduction. These studies represent an exciting new possibility in the management of ALI/ARDS.
The goal of this study is to develop new approaches to the management of acute lung injury and acute respiratory distress syndrome, conditions that carry a high degree of mortality. We propose a novel approach aimed at restoring the known dysfunction and increased permeability of lung capillary vessels.
|Sun, Xutong; Kumar, Sanjiv; Sharma, Shruti et al. (2014) Endothelin-1 induces a glycolytic switch in pulmonary arterial endothelial cells via the mitochondrial translocation of endothelial nitric oxide synthase. Am J Respir Cell Mol Biol 50:1084-95|
|Aggarwal, Saurabh; Gross, Christine M; Rafikov, Ruslan et al. (2014) Nitration of tyrosine 247 inhibits protein kinase G-1? activity by attenuating cyclic guanosine monophosphate binding. J Biol Chem 289:7948-61|
|Gonzales, Joyce N; Gorshkov, Boris; Varn, Matthew N et al. (2014) Protective effect of adenosine receptors against lipopolysaccharide-induced acute lung injury. Am J Physiol Lung Cell Mol Physiol 306:L497-507|
|Xu, Yiming; An, Xiaofei; Guo, Xin et al. (2014) Endothelial PFKFB3 plays a critical role in angiogenesis. Arterioscler Thromb Vasc Biol 34:1231-9|
|Gross, Christine M; Aggarwal, Saurabh; Kumar, Sanjiv et al. (2014) Sox18 preserves the pulmonary endothelial barrier under conditions of increased shear stress. J Cell Physiol 229:1802-16|
|Chen, Feng; Yu, Yanfang; Haigh, Steven et al. (2014) Regulation of NADPH oxidase 5 by protein kinase C isoforms. PLoS One 9:e88405|
|Czikora, István; Alli, Abdel; Bao, Hui-Fang et al. (2014) A novel tumor necrosis factor-mediated mechanism of direct epithelial sodium channel activation. Am J Respir Crit Care Med 190:522-32|
|Chen, Feng; Kumar, Sanjiv; Yu, Yanfang et al. (2014) PKC-dependent phosphorylation of eNOS at T495 regulates eNOS coupling and endothelial barrier function in response to G+ -toxins. PLoS One 9:e99823|
|Gonzales, Joyce N; Kim, Kyung-mi; Zemskova, Marina A et al. (2014) Low anticoagulant heparin blocks thrombin-induced endothelial permeability in a PAR-dependent manner. Vascul Pharmacol 62:63-71|
|Rafikov, Ruslan; Dimitropoulou, Christiana; Aggarwal, Saurabh et al. (2014) Lipopolysaccharide-induced lung injury involves the nitration-mediated activation of RhoA. J Biol Chem 289:4710-22|
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