Human lncRNA regulates Tie-1 expression in endothelial cells and is necessary for VEGF-induced tube formation and the disease connection. (A) A schematic of the 3 human lncRNA AS (h-AS) tie-1 transcripts is shown. (B) hAS-2 transfection in endothelial cells down-regulates Tie-1 protein levels compared with no-treatment control (NC), vector control (Vector), or hAS-1 or hAS-3 transfected lysates. (C) After transfection with empty vector and tie-1 noncoding RNAs h-AS1 or h-AS2, HUVECs were suspended in type I collagen gels and treated with vehicle or 100 ng/mL VEGF. After 24 hours of incubation, cells were photographed using QCapture Program (QImaging Inc). Representative images are shown for 2 independent experiments. Details of image capture are available in supplemental Methods. (D) Quantification of mean lengths of tubes formed with VEGF-treated transfected HUVECs. *P < .05. (E) Tissues from patients diagnosed with vascular anomalies have aberrant levels of tie-1AS lncRNA transcript compared with tie-1. Interestingly, RNA from normal placenta tissue shows an exact reverse pattern with high levels of tie-1 and low to nondetectable levels of tie-1AS lncRNA.