Alterations in vascular permeability are defining feature of diverse processes including inflammation, ischemia/reperfusion and ventilator-induced lung injury, and may increase alveolar flooding, leukocyte infiltration and hypoxemia leading to increased morbidity and mortality. Oxidative stress accompanying these pathologies results in increased levels of oxidized phospholipids (OxPL) in the pulmonary circulation. We have previously characterized a group of barrier-protective OxPLs in vitro and in vivo and described enhancement of basal pulmonary endothelial (EC) barrier function and attenuation of permeability increase caused by inflammatory agonists. Barrier protective effects of OxPLs have been linked to enhancement of peripheral actin cytoskeleton, increased interactions between cell-cell and cell-substrate junctions mediated by small GTPases Rac and Cdc42, and Rac-mediated attenuation of Rho-dependent pathways of endothelial hyper-permeability. Although importance of endothelial cytoskeleton in dynamic regulation of EC permeability is well recognized, the role of EC adhesive complexes in the EC barrier responses is less understood. Our preliminary studies strongly suggest that barrier protective effects of OxPLs in the models of lung EC barrier dysfunction induced by inflammatory agonists are mediated by cell-cell adhesive structures, which are regulated by small GTPases Rac and Rap1. Our studies indicate that Rac- and Rap1-dependent signaling is also involved in the OxPL- mediated inhibition of Rho pathway. We hypothesize that bioactive components of OxPLs promote the lung vascular barrier integrity via activation of Rap1-dependent engagement of adherens junctions and tight junctions. We also hypothesize that OxPL-induced enhancement of adherens junctions may inhibit Rho GTPase via its negative regulator p190RhoGAP controlled by adherens junctions and lipid rafts.
Specific Aim #1 will test a novel upstream mechanism of OxPL-induced Rac activation via engagement of lipid rafts and activation of GRP78 receptor.
Specific Aim #2 will evaluate involvement of Rap1 and its cell adhesion effector afadin in the OxPLs-induced adherens junction and tight junction enhancement.
Specific Aim #3 will explore a role of p190RhoGAP in the Rac- and Rap1-dependent mechanisms of OxPL-induced Rho inhibition. We believe that these studies will significantly impact our understanding of the role of oxidized phospholipids in the EC barrier regulation and will help to identify novel protein targets and propose new therapies for prevention of pulmonary vascular barrier dysfunction associated with acute lung inflammation and injury.

Public Health Relevance

The acute phase of lung injury is characterized by increased endothelial permeability and compromise of the blood-gas barrier, which allows an influx of protein-rich fluid into the air spaces, causing pulmonary edema. However, despite recent advances in ventilation strategies and a better understanding of the pathophysiology of ALI, there remain few effective treatments for this devastating illness. This application will investigate molecular mechanisms underlying protective effects of oxidized phospholipids against pulmonary vascular endothelial leak induced by edemagenic agonists and pathologic mechanical strain associated with acute lung injury and will characterize novel groups of barrier protective oxidized phospholipid compounds.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL076259-09
Application #
8267719
Study Section
Respiratory Integrative Biology and Translational Research Study Section (RIBT)
Program Officer
Harabin, Andrea L
Project Start
2004-06-01
Project End
2014-05-31
Budget Start
2012-06-01
Budget End
2014-05-31
Support Year
9
Fiscal Year
2012
Total Cost
$386,100
Indirect Cost
$138,600
Name
University of Chicago
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
Tian, Yufeng; Gawlak, Grzegorz; O'Donnell 3rd, James J et al. (2016) Activation of Vascular Endothelial Growth Factor (VEGF) Receptor 2 Mediates Endothelial Permeability Caused by Cyclic Stretch. J Biol Chem 291:10032-45
Gawlak, Grzegorz; Son, Sophia; Tian, Yufeng et al. (2016) Chronic high-magnitude cyclic stretch stimulates EC inflammatory response via VEGF receptor 2-dependent mechanism. Am J Physiol Lung Cell Mol Physiol 310:L1062-70
Birukova, Anna A; Shah, Alok S; Tian, Yufeng et al. (2016) Dual role of vinculin in barrier-disruptive and barrier-enhancing endothelial cell responses. Cell Signal 28:541-51
Birukova, Anna A; Shah, Alok S; Tian, Yufeng et al. (2016) Selective Role of Vinculin in Contractile Mechanisms of Endothelial Permeability. Am J Respir Cell Mol Biol 55:476-486
Wu, Congqing; Huang, Ru-Ting; Kuo, Cheng-Hsiang et al. (2015) Mechanosensitive PPAP2B Regulates Endothelial Responses to Atherorelevant Hemodynamic Forces. Circ Res 117:e41-53
Birukova, Anna A; Meng, Fanyong; Tian, Yufeng et al. (2015) Prostacyclin post-treatment improves LPS-induced acute lung injury and endothelial barrier recovery via Rap1. Biochim Biophys Acta 1852:778-91
Meng, Fanyong; Mambetsariev, Isa; Tian, Yufeng et al. (2015) Attenuation of lipopolysaccharide-induced lung vascular stiffening by lipoxin reduces lung inflammation. Am J Respir Cell Mol Biol 52:152-61
Meliton, Angelo Y; Meng, Fanyong; Tian, Yufeng et al. (2015) Oxidized phospholipids protect against lung injury and endothelial barrier dysfunction caused by heat-inactivated Staphylococcus aureus. Am J Physiol Lung Cell Mol Physiol 308:L550-62
Meliton, Angelo; Meng, Fanyong; Tian, Yufeng et al. (2015) Role of Krev Interaction Trapped-1 in Prostacyclin-Induced Protection against Lung Vascular Permeability Induced by Excessive Mechanical Forces and Thrombin Receptor Activating Peptide 6. Am J Respir Cell Mol Biol 53:834-43
Heisler, David B; Kudryashova, Elena; Grinevich, Dmitry O et al. (2015) ACTIN-DIRECTED TOXIN. ACD toxin-produced actin oligomers poison formin-controlled actin polymerization. Science 349:535-9

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