DNA Enzyme ED5 Depletes Egr-1 and Inhibits Neointimal Hyperplasia in Rats

Abstract

Objectives: Depletion of early growth response factor-1 (Egr-1) by a DNA enzyme, ED5, inhibits neointimal hyperplasia (NH) following vascular injury by an unknown mechanism. The aim of this study was to characterize the effects of ED5 in a rat carotid injury model in order to elucidate the mechanism by which ED5 inhibits NH. Methods: ED5 was transfected into the arterial wall of Wistar rats using FuGENE6 transfection reagent following artery balloon injury. Hematoxylin and eosin staining, immunohistochemistry, real-time reverse transcription polymerase chain reaction and Western blotting analysis were used to characterize the response to ED5. Results: NH decreased significantly in the ED5- plus FuGENE6-treated rats (p < 0.05) compared with the control groups, and this was accompanied by a reduced inflammatory response. Egr-1 mRNA and protein levels were significantly decreased in the ED5-treated group, as expected. The decrease in Egr-1 was accompanied by decreases in the mRNA and protein levels of PDGF-BB, Cyclin D1, CDK4, MCP-1, and ICAM-1 (p < 0.05). Conclusions: Transfection of the Egr-1-specific synthetic DNA enzyme ED5 significantly reduced NH after injury in rats, at least in part, as a result of decreased expression of downstream proliferative genes such as PDGF-BB, Cyclin D1, CDK4, and the inflammatory factors MCP-1 and ICAM-1.