Decreased miR-221/222 levels in CAD patients and the contribution of miR-221/222 in late EPC functions. (A-B) RT-qPCR results show miR-221/222 expression levels in late EPCs (A) and plasma (B) from health controls and CAD patients. ***: p < 0.0001 by Mann–Whitney test. (C) RT-qPCR results of miR-221 (left), miR-222 (middle) and pri-miR-221/222 (right) levels in late EPCs treated with recombinant VEGFA (n = 3). *: p < 0.05. (D) Tube formation (upper) and Transwell migration (lower) assays were performed in late EPCs transfected with indicated miRNAs for evaluation of endothelial functions. Left histograms: RT-qPCR of miRNA expression levels; Right histograms: quantitative results of tube formation and migration assays (n = 3). **: p < 0.01, ***: p < 0.001. (E-F) Overexpression of miR-221 or miR-222 in zebrafish embryos causes abnormal blood vascular development. Embryos in the Tg(kdrl:EGFP)s843 background were injected with 460 pg of negative control RNA (n = 100), 560 pg RNA of miR-221 (n = 106), or 560 pg RNA of miR-222 (n = 62). Blood vessel patterns were observed (E) and quantified (F) 48 hours postfertilization (hpf). DLAV: dorsal longitudinal anastomotic vessel; ISV: intersegmental vessels; DA: dorsal aorta; PCV: posterior cardinal vein.