The effect of proteases on endothelial cell migration in vitro

This communication reports on the role of proteases in the migration of endothelial cells in vitro. Endothelial cell (EC) migration was assayed by wounding confluent monolayers of bovine aortic endothelial cells with a razor blade and counting the number of cells crossing the wound per unit time. Treatment with mitomycin C inhibited wound-induced proliferation of endothelial cells without affecting migration, indicating that in this assay migration could be measured independent of proliferation. Migration of endothelial cells in vitro in 10% serum was not affected by depletion of plasminogen, which inhibited plasmin production, or by various protease inhibitors: soybean trypsin inhibitor, Trasylol, E-amino caproic acid (EACA), ovalbumin, p-tpsyl-1-arginine-methyl ester (TAME), and benzamidine. However, migration and proliferation of endothelial cells in vitro was inhibited by acid-treated serum, a procedure commonly used to inactivate protease inhibitors. Migration of bovine smooth muscle cells, 3T3 cells and SV40-3T3 cells was inhibited by plasminogen-depleted serum; reconstitution with purified plasminogen reversed the depressed migration of only SV40-3T3. These results indicated that endothelial cell migration in vitro is not dependent on plasminogen, which may be another unique property of endothelial cells.