Small Interfering Rna Targeting Pgc-1 Alpha Inhibits Vegf Expression And Tube Formation In Human Retinal Vascular Endothelial Cells

AIM: To determine whether small interfering RNA (siRNA) of PGC-1 alpha could inhibit vascular endothelial growth factor (VEGF) expression and tube formation in human retinal vascular endothelial cells (hRVECs).METHODS: hRVECs transfected with peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1 alpha) siRNA were incubated for 24h and then placed into a normoxic (20%, O-2) or hypoxic (1%, O-2) environment for another 16h. PGC-1 alpha mRNA and protein levels were detected by real -time PCR and Western blot. VEGF mRNA and protein levels were detected by real-time PCR and ELISA. Cell proliferation was evaluated by BrdU incorporation assay. Forty -eight hours after siRNA transfection, hRVECs were planted into Matrigel -coated plates and cultured under normoxic (20%, O-2) or hypoxic (1%, O-2) conditions for another 48h. The tube formation of hRVECs was observed under an optical microscope and quantified by counting the number of branch points and calculating the total tube length.RESULTS: PGC-1 alpha mRNA and protein levels were significantly reduced by PGC-1 alpha siRNA, and VEGF mRNA and protein levels also decreased significantly. The percentage of BrdU -labeled cells in siPGC-1 alpha groups were significantly decreased compared with control siRNA groups under normoxia and hypoxia in cell proliferation assay. In the tube formation assay, PGC-1 alpha siRNA treated cells formed significantly fewer tubes.CONCLUSION: Blocking PGC-1 alpha expression can inhibit VEGF expression in hRVECs and inhibit their ability to form tubes under both normoxic and hypoxic conditions.