Urokinase localization and activity in isolated eosinophils.
Urokinase-type plasminogen activator is implicated in cell invasion and migration. In this study, we provide evidence for the presence of urokinase-type plasminogen activator (3.5 +/- 1.5 ng/mg of cell protein) in isolated peripheral blood eosinophils, in comparison to 6.7 +/- 2.3 ng/mg of protein in neutrophils. Both immunocytochemical and immunogold staining of urokinase-type plasminogen activator on electron microscopy showed its localization in granules of resting cells. Mild stimulation by platelet-activating factor induced a translocation of urokinase-type plasminogen activator from the granules to the cell membrane and a formation of urokinase-type plasminogen activator capping, suggesting a role for urokinase-type plasminogen activator in eosinophil migration. The activation of eosinophils led to the release of factor(s) which, after activation of pro-urokinase-type plasminogen activator, induced an inactivation of generated urokinase-type plasminogen activator. Our results suggest that urokinase-type plasminogen activator is implicated in activated eosinophils invasiveness because the exposure of urokinase-type plasminogen activator is regulated both in space and time.
Mabilat-Pragnon
C
C
INSERM U353, Hôpital Saint-Louis, Paris, France. c.pragnon@chu-stlouis.fr
Janin
A
A
Michel
L
L
Thomaïdis
A
A
Legrand
Y
Y
Soria
C
C
Lu
H
H
D001693:Biological Transport, Active / Q000187:drug effects; D002462:Cell Membrane / Q000201:enzymology; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D003594:Cytoplasmic Granules / Q000201:enzymology; D004804:Eosinophils / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D016253:Microscopy, Immunoelectron; D009504:Neutrophils / Q000201:enzymology; D010972:Platelet Activating Factor / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000378:metabolism; D055293:Receptors, Urokinase Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism*
C524898:PLAUR protein, human; D010972:Platelet Activating Factor; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator