Neutrophil tethering on E-selectin activates β2 integrin binding to ICAM-1 through a mitogen-activated protein kinase signal transduction pathway

On inflamed endothelium selectins support neutrophil capture and rolling that leads to firm adhesion through the activation and binding of beta(2) integrin, The primary mechanism of cell activation involves ligation of chemotactic agonists presented on the endothelium. We have pursued a second mechanism involving signal transduction through binding of selectins while neutrophils tether in shear how, We assessed whether neutrophil rolling on E-selectin led to cell activation and arrest via beta(2) integrins. Neutrophils were introduced into a parallel plate flow chamber having as a substrate an L cell monolayer coexpressing E-selectin and ICAM-1 (E/I), At shears greater than or equal to 0.1 dyne/cm(2), neutrophils rolled on the E/I, A step increase to 4.0 dynes/cm(2) revealed that similar to 60% of the interacting cells remained firmly adherent, as compared with similar to 10% on L cells expressing E-selectin or ICAM-1 alone. Cell arrest was dependent on application of shear and activation of Mac-1 and LFA-1 to bind ICAM-1, Firm adhesion was inhibited by blocking E-selectin, L-selectin, or PSGL-1 with Abs and by inhibitors to the mitogen-activated protein kinases, A chimeric soluble E-selectin-IgG molecule specifically bound sialylated ligands on neutrophils and activated adhesion that was also inhibited by blocking the mitogen-activated protein kinases, We conclude that neutrophils rolling on E-selectin undergo signal transduction leading to activation of cell arrest through beta(2) integrins binding to ICAM-1.