776. Adenoviral Mediated Gene Transfer of NOS Isoforms and Vascular Cell Proliferation

Abstract

Top of pageAbstract Background: Smooth muscle cell (SMC) proliferation is a central component of multiple vascular disorders. Nitric oxide (NO) has been shown to inhibit SMC proliferation. NO production may be augmented by gene delivery of nitric oxide synthase (NOS). A number of NOS isoforms exist and the aim of this study was to compare the effectiveness of these iosforms in the modulation of vascular SMC proliferation using adenoviral vectors. Methods: SMCs were transduced with adenoviral vectors encoding eNOS (AdeNOS), nNOS (AdnNOS), iNOS (AdiNOS) or empty adenoviral vector (AdNull) at a multiplicity of infection (MOI) of 100. Non-transduced cells served as additional controls. Transgene expression was sought by western blotting. Effects on cell proliferation were determined by cell counting on day 0, 3 and 6. Apoptosis was sought by Hoechst staining and DNA laddering. Results: Expression of all three isoforms was detected in transduced cells. Cell proliferation was diminished in AdeNOS (25.55 ± 3.63% Day6), AdnNOS(22.28 ± 4.7% Day6) and to a lesser extent AdiNOS (69.37 ± 7.49% Day6) transduced cells in comparison with AdNull (100% Day6) transduced and non-transduced cells on day 3 and 6. Apoptosis was not detected in any of the SMCs either by Hoechst staining or DNA fragmentation. Summary: eNOS and nNOS gene transfer to SMCs result in an inhibition on SMC proliferation. iNOS gene transfer also results in an inhibition of SMC proliferation but not to the same extent as the other isoforms. Apoptosis was not observed with any isoform. Conclusion: Overexpression of all NOS isoforms inhibits SMC proliferation but iNOS is the least effective.