Recruitment of the adaptor protein Nck to PECAM-1 couples oxidative stress to canonical NF-κB signaling and inflammation

Oxidative stress stimulates nuclear factor kappa B (NF-kappa B) activation and NF-kappa B-dependent proinflammatory gene expression in endothelial cells during several pathological conditions, including ischemia/reperfusion injury. We found that the Nck family of adaptor proteins linked tyrosine kinase signaling to oxidative stressinduced activation of NF-kappa Bthrough the classic IkBkinase-dependent pathway. Depletion of Nck prevented oxidative stress induced by exogenous hydrogen peroxide or hypoxia/reoxygenation injury from activating NF-kappa B in endothelial cells, increasing the abundance of the proinflammatorymolecules ICAM-1 (intracellular adhesion molecule-1) and VCAM-1 (vascular cell adhesion molecule-1) and recruiting leukocytes. Nck depletion also attenuated endothelial cell expression of genes encoding proinflammatory factors but not those encoding antioxidants. Nck promoted oxidative stress-induced activation ofNF-kappa B by coupling the tyrosine phosphorylation of PECAM-1 (platelet endothelial cell adhesion molecule-1) to the activation of p21-activated kinase, which mediates oxidative stress-induced NF-kappa B signaling. Consistent with thismechanism, treatment ofmice subjected to ischemia/reperfusion injury in thecremastermusclewith a Nck inhibitory peptide blocked leukocyte adhesion and emigration and the accompanying vascular leak. Together, these data identify Nck as an important mediator of oxidative stress-induced inflammation and a potential therapeutic target for ischemia/reperfusion injury.