In Project 4, we will test the hypotheses that (i) Nox2-dependent oxidant signaling activates Src kinas dependent ICAM-1-phosphorylation and thereby the recruitment of PMNs in the pulmonary circulation, and that (ii) Src phosphorylation of ICAM-1 in turn protracts Src activation and phosphorylation of caveolin-1 and dynamin-2, thereby triggering caveolae-mediated transcytosis of albumin and endothelial hyper-permeability. These studies will address the following Specific Aims: (1) role of PI3-kinase, PKC zeta, Nox2, and Src signaling, and of Akt phosphorylation of filamin A in the mechanism of ICAM-1 phosphorylation, clustering, and rapid increase in ICAM-1 binding affinity in lung microvascular endothelial cells and PMN uptake in lungs;(2) role of phospho-ICAM-1 in recruitment of SHP2 and protracting Src activation and thereby caveolin-1 and dynamin-2 activation, and thus stimulating caveolae-mediated transcytosis and hyper-permeability of albumin. Project 4 will delineate the signaling mechanisms mediating the post-translational modification of ICAM-1 in pulmonary microvessel endothelial cells using imaging, cell biology, biochemical, and physiological approaches. We will thereby establish how endothelial cell ICAM-1 shifts to a high-affinity state and promotes PMN adhesion and sequestration and also induces caveolae-mediated hyper-permeability via the transcytosis of albumin. These studies it is hoped will lead to a new understanding of the early PMN-mediated lung inflammatory response and its coupling to lung vascular hyper-permeability. Identification of the key signaling hubs of ICAM-1-mediated endothelial adhesivity and activation of the caveolae-mediated albumin transport pathway is likely to provide novel therapeutic targets directed against inflammatory lung injury.
We will elucidate the role of Src-activated signaling mechanism regulating endothelial adhesivity and thereby permeability of lung microvessels. The proposed studies will for the first time establish the potentially important relationship between Src-activation of ICAM-1, neutrophil adhesion, and activation of the caveolar permeability machinery. Project 4 studies will thus define a novel pathogenic mechanism of ALI/ARDS.
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|Piegeler, Tobias; Dull, Randal O; Hu, Guochang et al. (2014) Ropivacaine attenuates endotoxin plus hyperinflation-mediated acute lung injury via inhibition of early-onset Src-dependent signaling. BMC Anesthesiol 14:57|
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|Tobin, Matthew K; Bonds, Jacqueline A; Minshall, Richard D et al. (2014) Neurogenesis and inflammation after ischemic stroke: what is known and where we go from here. J Cereb Blood Flow Metab 34:1573-84|
|Yang, Kai-Chien; Rutledge, Cody A; Mao, Mao et al. (2014) Caveolin-1 modulates cardiac gap junction homeostasis and arrhythmogenecity by regulating cSrc tyrosine kinase. Circ Arrhythm Electrophysiol 7:701-10|
|Mehta, Dolly; Ravindran, Krishnan; Kuebler, Wolfgang M (2014) Novel regulators of endothelial barrier function. Am J Physiol Lung Cell Mol Physiol 307:L924-35|
|Mittal, Manish; Siddiqui, Mohammad Rizwan; Tran, Khiem et al. (2014) Reactive oxygen species in inflammation and tissue injury. Antioxid Redox Signal 20:1126-67|
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