The activation of PAR1 inhibits capillary-like tube formation by ECFCs on Matrigel.

<p>10⁴ ECFCs/well were plated onto Matrigel matrix in tube formation assay buffer (i.e. EBM-2 medium containing 2% FBS). Cells were cultured with 50 µM scrambled control peptide, 50 µM PAR1-activating peptide or 50 µM PAR2-activating peptide in the absence or presence of 50 µM PD98059 (as indicated). Phase contrast images were captured 4 hours after cell seeding. Representative examples from 4 independent experiments are shown in (A). The number of tubes per image was quantified using the Angiogenesis Analyzer plugin for ImageJ. Means ± SEM from three independent experiments are shown in (B). Statistical significance was tested by one-way ANOVA with Bonferroni post-test (** = p<0.05). Time-dependent activation of ERK1/2 by PAR1-activating peptide (0, 1, 2 and 4 hours) and its inhibition by 50 µM PD98059 were examined using a phospho-specific ERK1/2 antibody and immunoblotting (C). The results are representative of three independent experiments.