Figure 4. High-glucose-induced increase of vascular endothelial growth factor (VEGF) gene transcription by recruitment of heparanase binding to the VEGF gene promoter. Human retinal endothelial cells (HRECs) incubated with normal medium or high glucose for 72 h were subjected to a chromatin immunoprecipitation (ChIP) assay with the indicated antibodies. The VEGF gene promoter of the RNA polymerase II (Pol II) binding protein A agarose DNA–antigen–antibody complex increased in the high-glucose group compared with the control group, denoting transcription upregulation of the VEGF gene. The expression of the VEGF gene promoter of the heparanase antibody binding protein A agarose DNA–antigen–antibody complex was higher in the high glucose group than in the control group. ChIP data were quantified by real-time PCR analysis. *p<0.05 versus control.