title: Identification of urokinase-type plasminogen activator receptor in human endothelial cells and its modulation by phorbol myristate acetate.
abstract: Human endothelial cells express antithrombotic properties by producing prostacyclin, heparan sulfate and plasminogen activator (PA). Using an established cell line, TKM-33, from human umbilical vein endothelial cells, the pericellular urokinase-type PA (u-PA) activity and expression of u-PA receptor (u-PAR) were investigated. The endothelial cells produced and secreted large amounts of u-PA and low levels of tissue-type PA (t-PA) and of PA inhibitor-1 (PAI-1), which were identified by immunohistochemical study and electrophoretic enzymography. Diisopropylfluoro-phosphate-treated 125I-u-PA bound specifically to acid-treated monolayered endothelial cells with a Kd of 3.46 +/- 1.17 nM, and Bmax of (0.09 +/- 0.04) x 10(6) sites/cell. mRNA of u-PAR was detected by using Northern blot analysis. Thus, these endothelial cells express u-PAR which bounds u-PA specifically. Phorbol myristate acetate (PMA) stimulation to the endothelial cells altered the Kd value to 3.18 +/- 0.64 nM, and Bmax value to (0.19 +/- 0.10) x 10(6) sites/cell, respectively. PMA treatment of endothelial cells increased u-PAR mRNA. Similarly, H7-treated endothelial cells showed a dose-dependent increase of u-PAR mRNA. However, PMA and H7 did not stimulate the expression of u-PA and t-PA mRNAs significantly. The expression of PAI-1 mRNA was increased by both PMA and H7. These findings suggest that the established endothelial cell line, TKM-33, possesses the character of endothelial cells and expresses u-PAR on their cell surface which is occupied by intrinsic u-PA secreted from the cells. The pericellular u-PA activity and the expression of u-PAR were regulated by protein kinase pathway.
authors.affiliation: Department of Physiology, Kinki University School of Medicine, Osakasayama, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Matsumoto
authors.forename: S
authors.initials: S
authors.lastname: Ueshima
authors.forename: H
authors.initials: H
authors.lastname: Fukao
authors.forename: Y
authors.initials: Y
authors.lastname: Mitsui
authors.forename: O
authors.initials: O
authors.lastname: Matsuo
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000494:pharmacology*; D002460:Cell Line; D004727:Endothelium / Q000166:cytology; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007457:Iodine Radioisotopes / Q000378:metabolism; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics / Q000378:metabolism*; D010960:Plasminogen Activators / Q000037:antagonists & inhibitors / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
chemical_list: D007457:Iodine Radioisotopes; C524898:PLAUR protein, human; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D010960:Plasminogen Activators; D013755:Tetradecanoylphorbol Acetate