CATIONIC POLYMER AND LIPIDS ENHANCE ADENOVIRUS-MEDIATED GENE-TRANSFERTO RABBIT CAROTID-ARTERY

Background and Purpose-Improvement of efficiency of gene transfer to e ndothelium could be useful for several applications. We tested the hyp othesis that cationic nonviral molecules augment adenovirus-mediated g ene transfer to blood vessels, perhaps by alteration of the surface ch arge of adenovirus and facilitation of binding to endothelium. Methods -Carotid arteries from rabbits were incubated in vitro for 0.5 to 2 ho urs with an adenoviral vector alone or noncovalent complexes of adenov irus with poly-L-lysine (a cationic polymer) or lipofectin (a cationic lipid). Binding of adenovirus to the vessels was evaluated immediatel y after incubation with virus, and assay of transgene (beta-galactosid ase) activity and histochemistry were performed 24 hours after gene tr ansfer. To determine whether cationic molecules can be used to augment alteration of vascular function by adenovirus-mediated gene transfer, we also examined effects on gene transfer of endothelial nitric oxide synthase, Results-Assay of beta-galactosidase activity indicated that both cationic molecules increased transgene expression in vessels by approximate to 5- to 6-fold. In contrast, when endothelium was removed from the vessels after gene transfer, poly-L-lysine and lipofectin di d not significantly increase transgene activity. Histochemistry for be ta-galactosidase also suggested that the adenovirus-cationic molecule complexes augmented transgene expression mainly in the endothelium. In addition, we found that complexing adenovirus with cationic molecules increased binding of adenovirus to the vessels, After gene transfer w ith recombinant adenovirus containing endothelial nitric oxide synthas e, calcium ionophore (A23187) produced greater relaxation of vessels t reated with adenovirus complexed with poly-L-lysine or lipofectin than those treated with adenovirus alone, Conclusions-Cationic molecules i mprove the efficiency of adenovirus-mediated gene transfer to blood ve ssels.