Fig. 3. VPA enhanced the levels of tissue plasminogen activator (tPA) expression in NPCs.

Cultured NPCs were treated with VPA (0.2 and 0.5 mM) for 3 h or 6 h. (A-C) The levels of tPA mRNA (A), protein (B), and activity (C) were analyzed with RT-PCR, western blot, and casein zymography, respectively. ^**p<0.01 and ^***p<0.001 vs. Vehicle 3 h, and ^#p<0.05 and ^##p<0.01 vs. Vehicle 6 h (one-way ANOVA followed by post hoc Tukey's comparisons test). (D) The NPCs were treated with histone acetylation inhibitors (HDAC) inhibitors or valpromide (VPM) for 6 h then tPA activity was analyzed; VPA (0.5 mM), trTSA (trichostatin A, 20 nM), SB (sodium butyrate, 0.1 mM), and VPM (0.5 mM). All data are expressed as mean±SEM (n=3). *p<0.05 and **p<0.01 vs. Vehicle (Student's t-test).