MicroRNA-29b-3p inhibits cell proliferation and angiogenesis by targeting VEGFA and PDGFB in retinal microvascular endothelial cells.

Purpose: Excessive angiogenesis, also known as neovascularization, has considerable pathophysiologic roles in several retinal diseases, including retinopathy of prematurity, diabetic retinopathy, and exudative age-related macular degeneration. Accumulated evidence has revealed that miRNAs play important roles in endothelial cell dysfunction and angiogenesis. However, the role of microRNA-29b-3p (miR-29b-3p) in retinal angiogenesis is still unclear. Therefore, we investigated whether and how miR-29b-3p affects the function of retinal microvascular endothelial cells (RMECs). Methods: The overexpression and inhibition of miR-29b-3p were achieved by transfecting rat RMECs with an miR-29b-3p mimic and inhibitor, respectively. The proliferation, migration, and angiogenesis of RMECs were evaluated using a Cell Counting Kit-8 assay, Ki67 staining, western blotting (of proliferating cell nuclear antigen, cyclin A2, cyclin D1, and cyclin E1), wound healing test, and tube formation assay. The expression levels of vascular endothelial growth factor A (VEGFA) and platelet-derived growth factor B (PDGFB) were examined with quantitative real-time PCR and western blotting, respectively. Results: Overexpression of miR-29b-3p statistically significantly inhibited the function of RMECs in cell proliferation and angiogenesis, while inhibition of miR-29b-3p increased the proliferative and angiogenic activities of RMECs. Moreover, VEGFA and PDGFB, as the targets of miR-29b-3p, were statistically significantly downregulated by the miR-29b mimic, whereas the miR-29b-3p inhibitor had the opposite effects. Conclusions: miR-29b-3p negatively regulates RMEC proliferation and angiogenesis, at least partly by targeting VEGFA and PDGFB. These data may provide a potential therapeutic strategy for treating ocular neovascular diseases.