SURFACTANT INHIBITS CATIONIC LIPOSOME-MEDIATED GENE TRANSFER

ABSTRACT We have demonstrated that tracheal insufflation of recombinant plasmid DNA results in transfection of rat lungs to the same extent as insufflation of plasmid–cationic liposome complex. To understand this observation better, we investigated the in vitro gene transfer of plasmid DNA in the presence and absence of cationic liposome and the effect of surfactant on gene transfer. The chloramphenicol acetyltransferase (CAT) expression plasmids pBL-CAT and pSV-CAT were studied in three cell types: rat fetal lung fibroblast (RFL-6), calf pulmonary artery endothelial cell (CPAE), and rat type II alveolar epithelial cell (type II AE). Three cationic liposomes were tested: DDAB (dimethyl-dioctadecyl ammonium bromide)–liposome, DOTAP (dioleoyltrimethyl ammonium propane)–liposome, and lipofectin. The results revealed that (i) plasmid DNA alone caused a dose-dependent, low-level transfection, most efficiently in RFL-6 followed by CPAE and type II AE, (ii) DDAB–liposome markedly enhanced gene transfer, most eff...