MicroRNA expression in HMVECs: control vs. VEGF-treated vs. PEDF/VEGF-treated

MicroRNA expression profiling of human microvascular endothelial cells (HMVECs) treated with either vascular endothelial growth factor (VEGF) only or in combination with the natural angiogenesis inhibitor pigment epithelial-derived factor (PEDF). Originally we were interested in the microRNA-mediated regulation of angiogenesis by the endogenous anti-angiogenic PEDF. To identify the microRNAs involved in PEDF signaling in activated endothelial cells, we compared the levels of microRNAs in non-treated microvascular endothelial cells, cells treated with VEGF, and cells treated with a combination of VEGF and PEDF. After treatment, total RNA content was isolated and sent for analysis to LC Sciences, LLC. They performed expression profiling and completed statistical analysis, based on which we confirmed the regulation of one of the microRNAs, mir-27b. In the following experiments, we identified the targets of mir-27b relevant for angiogenesis and confirmed our findings in zebrafish and mouse models. The manuscript describes the key role of mir-27b in determination of the endothelial tip cell fate and venous differentiation by regulating Notch ligand Delta-like ligand 4 (Dll4) and Sprouty homologue 2 (Spry2). Three-condition experiment: untreated (control) HMVECs vs. VEGF-treated HMVECs vs. PEDF/VEGF-treated HMVECs.