Neutrophil tethering on E-selectin activates beta(2) integrin binding to ICAM-1 through a mitogen-activated protein kinase signal transduction pathway

On inflamed endothelium selectins support neutrophil capture and rolling th at leads to firm adhesion through the activation and binding of beta(2) int egrin, The primary mechanism of cell activation involves ligation of chemot actic agonists presented on the endothelium. We have pursued a second mecha nism involving signal transduction through binding of selectins while neutr ophils tether in shear how, We assessed whether neutrophil rolling on E-sel ectin 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 great er than or equal to 0.1 dyne/cm(2), neutrophils rolled on the E/I, A step i ncrease 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 applica tion of shear and activation of Mac-1 and LFA-1 to bind ICAM-1, Firm adhesi on 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 neutrophi ls and activated adhesion that was also inhibited by blocking the mitogen-a ctivated protein kinases, We conclude that neutrophils rolling on E-selecti n undergo signal transduction leading to activation of cell arrest through beta(2) integrins binding to ICAM-1.