title: Dexamethasone-induced translocation of lipocortin (annexin) 1 to the cell membrane of U-937 cells.
abstract: Lipocortin (annexin) 1 is a putative mediator of the inflammatory effects of glucocorticoids. By flow cytometric analysis (FACS) we have studied the effect of dexamethasone on the cellular localization of lipocortin 1. U-937 cells were incubated with or without 10 nM phorbol 12-myristate 13-acetate (PMA) to induce cell differentiation. Then 1 microM dexamethasone was added and incubation carried out for increasing times (1-24 h). Dexamethasone caused a time-dependent biphasic translocation of lipocortin 1 from the intracellular compartment to the cell membrane with maximal membrane expression at 4 and 24 h. In differentiated U-937 cells the steroid-induced membrane accumulation of lipocortin 1 was significantly higher than that of undifferentiated cells. The accumulation of the protein in the cell membrane may precede its release which is stimulated by dexamethasone in differentiated U-937 cells. Since extracellular lipocortin 1 has anti-inflammatory properties the modulation of the translocation/secretion process of the protein by glucocorticoids may be part of their mechanism of action.
authors.affiliation: Department of Pharmacology, Immunobiology Research Institute Siena, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Solito
authors.forename: S
authors.initials: S
authors.lastname: Nuti
authors.forename: L
authors.initials: L
authors.lastname: Parente
mesh_terms: D017305:Annexin A1 / Q000096:biosynthesis / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D013755:Tetradecanoylphorbol Acetate / Q000493:pharmacokinetics
chemical_list: D017305:Annexin A1; D003907:Dexamethasone; D013755:Tetradecanoylphorbol Acetate