(A–C) CFs were serum-starved for 24h and then stimulated with 0 – 100 µM UTP for 4h. Cells were assayed by real-time RT-PCR to quantify mRNA expression and immunoblot analysis to quantify protein expression of PAI-1. UTP dose-dependently increased PAI-1 mRNA expression (A) and protein expression (B). (C) Quantification of PAI-1 protein from two independent Western blots is shown as ± SEM compared by using ANOVA with post-hoc multiple comparison tests. *, p<0.05 and **, p<0.01. (D) Time-dependent increase in PAI-1 protein expression was observed after 2 h, peaked after 4 h and decreased to baseline levels after 24 h. (E) Quantification is shown from two independent Western blots as ± SEM compared by using ANOVA with post-hoc multiple comparison tests. **, p<0.01 and ***, p<0.001.