Differential ability of human endothelial cells to internalize and express exogenous DNA

Vascular endothelium gene expression regulates blood-vessel wall interactions, vascular permeability, smooth muscle cell growth and tone. The possibility to introduce exogenous DNA or RNA sequences in endothelial cells represents a novel therapeutic approach of vascular disease. The aim of the work was to investigate the ability of endothelial cells to internalize and express exogenous DNA sequences. Human umbilical vein endothelial cells (HUVEC) were transfected with either a 780 bp fluorescein-labeled DNA (FITC-DNA) or pEGFP-C1 plasmid encoding for a green fluorescent protein (GFP), using the cationic liposome DOTAP as transfection reagent. The transfected cell population was passed through a FACScan apparatus and percentage of fluorescent cells was determined using a FACScan analysis programme. The SW620 tumor-derived cell line was used as control. The percentage of FITC-DNA positive cells was 66.0% for HUVEC and 45.0% for SW620 cells. On the contrary, the percentage of GFP-positive cells was 13.8% and 43% for HUVEC and SW620, respectively. By increasing the amount of DNA as well as the protocol of administration the percentage of GFP-positive HUVEC was enhanced suggesting a rapid degradation of DNA in the HUVEC cytoplasm.