title: Platelet-activating factor increases VE-cadherin tyrosine phosphorylation in mouse endothelial cells and its association with the PtdIns3'-kinase.
abstract: Platelet-activating factor (PAF), a potent inflammatory mediator, is involved in endothelial permeability. This study was designed to characterize PAF receptor (PAF-R) expression and its specific contribution to the modifications of adherens junctions in mouse endothelial cells. We demonstrated that PAF-R was expressed in mouse endothelial cells and was functionally active in stimulating p42/p44 MAPK and phosphatidylinositol 3-kinase (PtdIns3'-kinase)/Akt activities. Treatment of cells with PAF induced a rapid time- and dose-dependent (10(-7) to 10(-10) M) increase in tyrosine phosphorylation of a subset of proteins ranging from 90 to 220 kDa, including the VE-cadherin, the latter effect being prevented by the tyrosine kinase inhibitors herbimycin A and bis-tyrphostin. We demonstrated that PAF promoted formation of multimeric aggregates of VE-cadherin with PtdIns3'-kinase, which was also inhibited by herbimycin and bis-tyrphostin. Finally, we show by immunostaining of endothelial cells VE-cadherin that PAF dissociated adherens junctions. The present data provide the first evidence that treatment of endothelial cells with PAF promoted activation of tyrosine kinases and the VE-cadherin tyrosine phosphorylation and PtdIns3'-kinase association, which ultimately lead to the dissociation of adherens junctions. Physical association between PtdIns3'-kinase, serving as a docking protein, and VE-cadherin may thus provide an efficient mechanism for amplification and perpetuation of PAF-induced cellular activation.
authors.affiliation: INSERM EMI 02-19, Laboratoire de Développement et Vieillissement de L'Endothélium, Département Réponse Dynamique Cellulaire, Commissariat à l'Energie Atomique, Grenoble Cedex 9, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Hudry-Clergeon
authors.forename: Dominique
authors.initials: D
authors.lastname: Stengel
authors.forename: Ewa
authors.initials: E
authors.lastname: Ninio
authors.forename: Isabelle
authors.initials: I
authors.lastname: Vilgrain
mesh_terms: D022005:Adherens Junctions / Q000187:drug effects / Q000648:ultrastructure; D000818:Animals; D015703:Antigens, CD; D016227:Benzoquinones; D015820:Cadherins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D004622:Embryo, Mammalian; D042783:Endothelial Cells / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D006321:Heart; D007163:Immunosorbent Techniques; D047908:Intracellular Signaling Peptides and Proteins / Q000494:pharmacology; D047029:Lactams, Macrocyclic; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation; D010972:Platelet Activating Factor / Q000494:pharmacology*; D010980:Platelet Membrane Glycoproteins / Q000032:analysis / Q000235:genetics / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011809:Quinones / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D043562:Receptors, G-Protein-Coupled / Q000032:analysis / Q000235:genetics / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017828:Rifabutin / Q000031:analogs & derivatives; D014443:Tyrosine / Q000378:metabolism*; D020032:Tyrphostins / Q000494:pharmacology; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D016227:Benzoquinones; D015820:Cadherins; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D047029:Lactams, Macrocyclic; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D019869:Phosphatidylinositol 3-Kinases; D010972:Platelet Activating Factor; D010980:Platelet Membrane Glycoproteins; D011505:Protein-Tyrosine Kinases; D011809:Quinones; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D017828:Rifabutin; D014443:Tyrosine; D020032:Tyrphostins; D000099152:Cadherin 5; C039351:platelet activating factor receptor; C015482:protein kinase modulator; C020754:herbimycin