title: Adenosine inhibits thrombin-induced expression of tissue factor on endothelial cells by a nitric oxide-mediated mechanism.
abstract: Enhanced expression of tissue factor (TF) is associated with the occurrence of coronary disease, strokes and arterial thrombosis. We demonstrated previously that adenosine inhibits TF expression in human umbilical vein endothelial cells (HUVECs) stimulated with inflammatory mediators. In the present study, we evaluated the mechanism of adenosine-induced inhibition of TF expression in HUVECs. The adenosine inhibitory activity on thrombin-induced TF expression in HUVECs was potentiated by the NO precursor, l-arginine, but it was significantly suppressed by the NO scavenger, 2(4-carboxyphenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide, and by endothelial NO synthase inhibitors, N(G)-monomethyl-l-arginine and N(G)-nitro-l-arginine methyl ester, in a dose-dependent manner. The concentrations of nitrites, cGMP and cAMP in the culture medium of HUVECs treated with a mixture of thrombin and adenosine were significantly higher compared with the culture medium of HUVECs treated with thrombin alone. Northern blotting showed that thrombin decreases and adenosine increases the eNOS mRNA expression in HUVECs. A cAMP-dependent protein kinase inhibitor suppressed NO-mediated TF inhibition in a dose-dependent manner. Overall, these results suggest that adenosine inhibits thrombin-induced TF expression in endothelial cells by a NO-mediated mechanism, and that increased intracellular formation of cAMP is implicated in this inhibitory activity of NO.
authors.affiliation: Department of Molecular Pathobiology, Mie University School of Medicine, Edobashi 2-174, Tsu, Mie 514-8507, Japan. gabazza@clin.medic.mie-u.ac.jp
authors.forename: Esteban C
authors.initials: EC
authors.lastname: Gabazza
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hayashi
authors.forename: Masaru
authors.initials: M
authors.lastname: Ido
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Adachi
authors.forename: Koji
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000241:Adenosine / Q000502:physiology*; D000249:Adenosine Monophosphate / Q000502:physiology; D001120:Arginine / Q000502:physiology; D015152:Blotting, Northern; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006157:Guanosine Monophosphate / Q000502:physiology; D006801:Humans; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052250:Nitric Oxide Synthase Type III; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D013917:Thrombin / Q000502:physiology*; D013925:Thromboplastin / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D010726:Phosphodiesterase Inhibitors; D009569:Nitric Oxide; D000249:Adenosine Monophosphate; D006157:Guanosine Monophosphate; D013925:Thromboplastin; D001120:Arginine; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D013917:Thrombin; D000241:Adenosine