title: Platelet-leukocyte interactions.
abstract: Platelet-leukocyte interactions may contribute to the development of several pathological conditions, including myocardial ischemic disorders. Using an in vitro system that simulates vascular flow conditions, we investigated platelet-neutrophil adhesion. Collagen-adherent platelets were shown to express P-selectin and were able to mediate the binding of flowing neutrophils. Some of the adherent neutrophils displayed signs of cellular activation. Flow cytometric analyses revealed that activation induced a rapid and marked reduction of the P-selectin ligand, with levels decreased by 71% after 15 minutes of stimulation. Using a visual assay of platelet-neutrophil rosetting, we showed that the P-selectin ligand was translocated and clustered at the uropod of neutrophils after the shape changes and polarization induced by stimulation. Activated neutrophils that were bound to surface-adherent platelets also displayed the clustering of P-selectin ligand at the uropod, and these neutrophils detached from the platelets when a shear stress was applied through the adhesion chamber. These results indicate that stimulation of neutrophils induces changes in the surface expression and distribution of the ligand for P-selectin, and that these changes might influence the adhesive interactions occurring between neutrophils and activated platelets.
authors.affiliation: Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, University of Montreal, Quebec, Canada. doremo@ere.umontreal.ca
authors.forename: M
authors.initials: M
authors.lastname: Doré
mesh_terms: D000818:Animals; D001775:Blood Circulation / Q000502:physiology; D001792:Blood Platelets / Q000378:metabolism / Q000502:physiology*; D002448:Cell Adhesion / Q000502:physiology; D002450:Cell Communication / Q000502:physiology*; D003094:Collagen / Q000502:physiology; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D007962:Leukocytes / Q000502:physiology*; D009504:Neutrophils / Q000378:metabolism / Q000502:physiology; D019007:P-Selectin / Q000378:metabolism; D010973:Platelet Adhesiveness / Q000502:physiology
chemical_list: D007074:Immunoglobulin G; D019007:P-Selectin; D003094:Collagen