title: Re-expression of functional P-selectin molecules on the endothelial cell surface by repeated stimulation with thrombin.
abstract: P-selectin (GMP-140, PADGEM, CD62P) is a cell adhesion receptor which is believed to play an important role in inflammatory diseases by supporting leucocyte rolling. P-selectin is located on the granule membrane of Weibel-Palade bodies in resting endothelial cells and is expressed on the cell surface during cellular activation with various stimulators such as thrombin. Thereafter, P-selectin is internalized and sorted to the Golgi region and Weibel-Palade bodies again. However, whether P-selectin is re-expressed upon subsequent cellular stimulation has, to date, been unclear. To address this question, we measured the cellular content and surface expression of P-selectin, using indirect immunofluorescence and confocal laser cytometry. Surface expression of P-selectin reached a maximum < 2 min after thrombin stimulation and declined to basal levels after 180 min. Rechallenge with thrombin induced rapid surface re-expression of P-selectin, which was independent of de novo protein synthesis, since cycloheximide did not inhibit re-expression. Moreover, re-expressed P-selectin supported the adherence of HL60 promyelocytic cells. These results clearly demonstrated that functional P-selectin molecule was recycled after repeated stimulation with thrombin, raising the possibility that P-selectin is involved in chronic inflammation.
authors.affiliation: Department of Internal Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kameda
authors.forename: I
authors.initials: I
authors.lastname: Morita
authors.forename: M
authors.initials: M
authors.lastname: Handa
authors.forename: J
authors.initials: J
authors.lastname: Kaburaki
authors.forename: T
authors.initials: T
authors.lastname: Yoshida
authors.forename: T
authors.initials: T
authors.lastname: Mimori
authors.forename: S
authors.initials: S
authors.lastname: Murota
authors.forename: Y
authors.initials: Y
authors.lastname: Ikeda
mesh_terms: D004730:Endothelium, Vascular / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D019007:P-Selectin / Q000378:metabolism*; D013917:Thrombin / Q000494:pharmacology*
chemical_list: D019007:P-Selectin; D013917:Thrombin