SP1 and Hyperglycemia: Donovan et al. [55] showed that hyperglycaemia significantly increased Sp1 binding to the gene promoter of the pro-angiogenic mediator vascular endothelial growth factor (VEGF)-A, while shRNA-mediated knockdown of either OGT or Sp1 significantly inhibited glucose-induced increases in VEGF-A levels in ARPE-19 human retinal pigment epithelial cells and TR-iBRB rat retinal microvascular endothelial cells.