ECs were transfected with either a sequence that exhibits no homology to the human genome (scramble) or DICER silencing RNA (siRNA) to knock down (KD) DICER for 24 hr, before being treated with either naive PF exosomes or PF exosomes previously depleted of their let-7b-5p content (exosome let-7b-5p KD). (A and B) Columns graphs show the relative expression of (A) let-7b-5p and (B) TGFBR1 in the exosome recipient ECs and untreated cell controls; n = 4. (C) Photomicrographs (the scale bar represents 100 μm) and (D) quantification of Matrigel assays performed using ECs treated as previously indicated; n = 5; 2.5× magnification. All values are mean + SEM. §p ≤ 0.05 and §§§p ≤ 0.001 versus scramble, *p ≤ 0.05 and ***p ≤ 0.001 versus DICER KD, #p ≤ 0.05 and ##p ≤ 0.01 DICER KD treated with naive PF exosomes (one-way ANOVA, Tukey’s post hoc test).