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

Abstract

Oxidative stress stimulates nuclear factor kB (NF-kB) activation and NF-kB-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 stress- induced activation of NF-kBthrough the classic IkBkinase-dependent pathway.Depletion of Nck prevented oxidative stress induced by exogenous hydrogen peroxide or hypoxia/reoxygenation injury from activating NF-kBin 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-kBby 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-kB signaling. Consistent with thismechanism, treatment ofmice subjected to ischemia/reperfusion injury in thecremastermusclewith aNck 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.