Plasminogen activator inhibitor type 1 (PAI-1)-induced microglial migration was independent of fibrinolysis or vitronectin binding. BV-2 microglial cells were treated with 100 ng/ml of mouse PAI-1, human wild-type PAI-1, or two variants (Q123K, R346A) of PAI-1 proteins, followed by a wound-healing assay as described in Figure 2. The wound recovery areas were visualized under an inverted microscope (upper panel), and the fold increase in migration distance was measured. Results are given as mean ± SD (n = 3). *P < 0.05, **P < 0.01; compared with the untreated control (lower panel).