Lipofectamine RNAiMAX (Thermo Fisher Scientific) was used to transfect HUVECs with scramble siRNA (75 nM total), siRNAs against DICER (25 nM for each siRNA, 75 nM total), mirVana miRNA mimic let-7b-5p (12.5 nM, MC11050), and mirVana miRNA inhibitor let-7b-5p (12.5 nM, MH11050), Pre-miR Negative Control (12.5 nM, AM17120) and Anti-miR Negative Control (12.5 nM, AM17011) (all from Thermo Fisher Scientific), according to the manufacturer’s instructions. Published sequences22, 44 of siRNA against DICER and scramble were used (all purchased from Qiagen).