title: Thrombin promotes endothelial cell alignment in Matrigel in vitro and angiogenesis in vivo.
abstract: We have tested the effect of thrombin on endothelial cell tube formation in vitro and angiogenesis in vivo. Thrombin induces the differentiation of endothelial cells into capillary structures in a dose-dependent fashion (0.1-0.3 units thrombin/ml) on Matrigel, a laminin-rich reconstituted basement membrane matrix. At higher thrombin concentrations (1.0 unit/ml), a suppression of tube formation is evident, probably due to downregulation (desensitization) of the thrombin receptor. D-Phe-Pro-Arg-CH2Cl-thrombin is without effect when used alone, but it abolishes the tube-promoting effect of thrombin when used in combination with thrombin, indicating the involvement of the catalytic site of thrombin. Activation of protein kinase C (PKC) seems to be the transduction mechanism involved in the stimulation of tube formation by thrombin. Ro-318220 (3 micrograms/ml), a specific inhibitor of PKC, completely abolishes the stimulatory effect of thrombin. In the in vivo Matrigel system of angiogenesis, there is a 10-fold increase in endothelial cell infiltration in response to thrombin. These results provide evidence for the angiogenesis-promoting effect of thrombin in vivo and the induction by thrombin of the angiogenic phenotype of endothelial cells in vitro in the absence of other cell types such as smooth muscle cells, pericytes, and inflammatory cells.
authors.affiliation: Department of Pharmacology, University of Patras Medical School, Greece.
authors.forename: G C
authors.initials: GC
authors.lastname: Haralabopoulos
authors.forename: D S
authors.initials: DS
authors.lastname: Grant
authors.forename: H K
authors.initials: HK
authors.lastname: Kleinman
authors.forename: M E
authors.initials: ME
authors.lastname: Maragoudakis
mesh_terms: D000818:Animals; D001485:Basement Membrane; D001672:Biocompatible Materials; D002478:Cells, Cultured; D003094:Collagen; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004338:Drug Combinations; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007797:Laminin; D051379:Mice; D008810:Mice, Inbred C57BL; D008955:Models, Cardiovascular; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000502:physiology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011509:Proteoglycans; D018179:Receptors, Thrombin / Q000096:biosynthesis / Q000502:physiology; D015398:Signal Transduction; D012867:Skin / Q000098:blood supply; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology*; D014471:Umbilical Veins
chemical_list: D001672:Biocompatible Materials; D004338:Drug Combinations; D004791:Enzyme Inhibitors; D007211:Indoles; D007797:Laminin; D011509:Proteoglycans; D018179:Receptors, Thrombin; C059485:matrigel; D003094:Collagen; D011493:Protein Kinase C; D013917:Thrombin; D013755:Tetradecanoylphorbol Acetate; C064758:Ro 31-8220