title: Chemoattractant-induced changes in surface expression and redistribution of a functional ligand for P-selectin on neutrophils.
abstract: Adhesion between platelets and neutrophils is mediated through the interaction of P-selectin on activated platelets with a carbohydrate-containing structure on neutrophils, and occurs under both static and shear conditions. Recent studies using flow chambers have shown that neutrophils become activated after binding to surface-adherent platelets expressing P-selectin. The objective of the present study was to investigate the effect of such activation on the interactions of platelet P-selectin with its ligand on neutrophils. Flow cytometric analyses using P-selectin chimeras revealed that activation induced a rapid and marked reduction in chimera binding, with levels of binding decreased by 71% after 15 minutes of stimulation with the chemotactic agent, FMLP. Using a visual assay of platelet-neutrophil rosetting, we showed that the P-selectin ligand was translocated and clustered at the uropod of neutrophils following the shape changes and polarization induced by chemotactic stimulation. Activated neutrophils 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 (2 dynes/cm2) was applied through the adhesion chamber. These results indicate that chemotactic stimulation of neutrophils induces changes in the surface expression and distribution of a biologically relevant 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, Université de Montréal, Québec, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Doré
authors.forename: A R
authors.initials: AR
authors.lastname: Burns
authors.forename: B J
authors.initials: BJ
authors.lastname: Hughes
authors.forename: M L
authors.initials: ML
authors.lastname: Entman
authors.forename: C W
authors.initials: CW
authors.lastname: Smith
mesh_terms: D000328:Adult; D000818:Animals; D001792:Blood Platelets / Q000378:metabolism; D018821:CD18 Antigens / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D016764:Cell Polarity / Q000187:drug effects; D002630:Chemotactic Factors / Q000494:pharmacology*; D004285:Dogs; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000235:genetics / Q000378:metabolism; D008024:Ligands; D016177:Macrophage-1 Antigen / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D019007:P-Selectin / Q000378:metabolism*; D011940:Receptor Aggregation / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013314:Stress, Mechanical
chemical_list: D018821:CD18 Antigens; D002630:Chemotactic Factors; D007141:Immunoglobulin Fc Fragments; D008024:Ligands; D016177:Macrophage-1 Antigen; D008565:Membrane Proteins; D019007:P-Selectin; D011993:Recombinant Fusion Proteins; D009240:N-Formylmethionine Leucyl-Phenylalanine