Figure 2.

DNA enzymes inhibit induction of endogenous PAI-1 mRNA and protein, demonstrate serum resistance, and reduce PAI-1 activity. (A and B) Results of RT-PCR and immunoblots demonstrating that transfection of rat endothelial monolayers with DNA enzyme E2 results in significant inhibition of TGF-β–induced expression of PAI-1 mRNA and protein, relative to the E0 scrambled DNA (P < 0.01 for both). (C) ³²P-labeled PAI-1 DNA enzyme with inverted thymidine at the 3′ end demonstrates resistance to degradation in culture with 2%, but not 20%, serum. (D) Transfection of HUVEC monolayers with the human PAI-1–specific DNA enzymes E1 or E3 reduces functional PAI-1 activity, as measured by chromogenic reaction of plasmin substrate (P < 0.01). (A, B, and D) Results are expressed as the mean ± SEM of three separate experiments.