Regulation of angiogenesis and vascular leak by miR-27. (A) HUVEC transfected with control (i and iii) or miR-27a mimic (ii and iv) and plated onto Matrigel. The retracted tubes are represented by a white arrow. The very thin tubes are represented by a black arrow. (i-ii) The scale bar indicates 200 µm. (iii-iv) The scale bar indicates 400 µm. (v) Number of capillary tubes formed per field of view, expressed as a percent relative to the control. *P < .05 cf control, n = 4 independent HUVEC lines, mean ± SEM. (B) Mice were implanted subcutaneously with Matrigel plugs containing fibroblast growth factor-2 and vehicle only (i,v), control (ii,vi), or miRNA-27a mimic (iii,vii). (i-iii) Representative histologic sections and hematoxylin and eosin–stained cross sections; the scale bar indicates 20 µm. (iv) Number of erythrocyte-containing vessels quantified. (v-vii) Representative CD31 immunochemistry. The scale bar indicates 50 µm. (viii) Number of CD31⁺ cells quantified. Data are expressed as mean ± SEM. Statistical analysis of differences was compared by 1-way analysis of variance with Bonferroni’s correction for multiple comparisons. Control (C) represents n = 3 mice and miRNA-27a and vehicle (V) represent n = 6 mice. (C) Reversal of the effect of miR-27a-mimics by overexpression of VE-cadherin. Cells were transfected with control mimic (i), miR-27a mimics (ii), VE-cadherin plasmid + control mimics (iii), or VE-cadherin expression plasmid + miR-27a-mimics (iv). 24 hours later, the cells were plated onto Matrigel and viewed over the following 24 hours. (D) Expression of miRNA-27a (open circles) and mRNA for VE cadherin (closed circles) over time after wounding monolayers of EC. Data are normalized to levels in the confluent cells. Expression levels were measured by qRT-PCR, with the results of miR-27a normalized to U48 and VE-cadherin normalized to β-actin. Results are from 2 to 4 independent HUVEC lines.