Thrombin Cleavage of Osteopontin Modulates Its Activities in Human Cells In Vitro and Mouse Experimental Autoimmune Encephalomyelitis In Vivo

Figure 5

Effect of OPN variants on angiogenesis. (a) HUVECs were plated onto the apical side of matrigel-coated filters in 50 μL of medium in the presence or absence of either 10 μg/mL OPN-FL, 5 μg/mL OPN-N, or OPN-C; VEGF-α (10 ng/mL) was loaded in the basolateral chamber as a positive control for migration. The cells that migrated to the bottom of the filters were stained using crystal violet and counted (5 fields for each triplicate filter) using an inverted microscope. Results are expressed as in Figure 4. (b) In the tube formation assay, HUVECs were plated in the presence and absence of OPN-FL (10 μg/mL), OPN-N (5 μg/mL), OPN-C (5 μg/mL), or VEGF-α (10 ng/mL), as a control. The morphology of capillary-like structures formed by HUVECs was analyzed 6 h after culturing. Results are expressed as means ± SEM from 3 experiments (; versus the control; ; versus OPN-FL; ; versus OPN-C; Wilcoxon’s signed rank test). Right panels show a representative tubulogenesis experiment.