Engagement of PSGL-1 enhances β2-integrin-involved adhesion of neutrophils to recombinant ICAM-1

Aim： The interactions of selectins and their ligands initiate the process of leukocyte migrating into inflamed tissue. P-selectin glycoprotein ligand 1 （PSGL-1） is the best characterized ligand of selectins, and has been demonstrated to mediate the adhesion of leukocytes to all three selectins in vivo. PSGL-1 not only functions as an anchor molecule to capture the leukocytes to the activated endothelial cells by its interaction with selectins, but also transduces the signals to activate leukocytes. Our present work aimed to investigate the mechanism by which PSGL-1-mediated signal activates neutrophils and enhances the adhesion to the endothelial cells. Methods： We detected the effects of the engagement of PSGL-1 with monoclonal antibodies （mAb） or P-selectin on the adhesion of neutrophils to the recombinant intercellular adhesion molecule-1 （ICAM-1）, and on the expres- sion of β2-integrin. Additionally, the role of cytoskeleton in these process was studied by using inhibitor cytochalasin B. Results： The engagement of PSGL-1 increased the expression of β2-integrin on the surface of neutrophils and enhanced the adhesion of neutrophils to the recombinant ICAM- 1. mAb against CD 18 impaired the adhesion of PSGL- 1-engaged neutrophils to ICAM- 1. Moreover, the inhibitor cytochalasin B largely blocked the increase of CD 18 expression as well as the adhesion of PSGL- 1-engaged neutrophils to ICAM- 1. Conclusion： The PSGL-1-transduced signals can enhance β2-integrin-involved adhesion of neutrophils to the recombinant ICAM-1, and this process depends on the dynamics of cytoskeleton.