Monosialoganglioside containing cationic liposomes with a cationic cholesterol derivative promote the efficiency of gene transfection in mammalian culture cells.

We have studied the effects of monosialoganglioside (GM1)-containing cationic liposomes with a cationic cholesterol on the liposome-mediated gene transfection into mammalian culture cells. The results showed that both cationic liposomes with either a cationic cholesterol derivative of a hydrophobic amino head group (I) and a hydrophilic amino head group (II) promoted the transfection of luciferase plasmids (pGL3) into HeLa and CHO-K1 cells more than the control cationic liposomes without GM1. In addition, we found that cationic liposomes with a cationic cholesterol derivative (II) were about ten times as effective as that by commercially available cationic liposome Lipofectin. Confocal fluorescence microscopy showed that the liposome/DNA complex was transferred more efficiently into the target cells by the GM1-containing liposomes than by the liposomes without GM1. In proportion to the above results, free antisense DNAs were also more efficiently transferred into the nucleus of the target cells by the GM1-containing liposomes. When there was 100 mM galactose in the transfection medium, the luciferase activity by the GM1-containing liposomes was reduced to the level of the control liposomes. The results suggest that GM1-containing cationic liposomes with a cationic cholesterol derivative of a hydrophobic amino head group or a hydrophilic amino head group should significantly increase the transfection efficiency of plasmid DNAs and antisense DNAs by galactose receptor-mediated endocytosis. This means that the GM1-containing liposomes described here should be very promising for gene transfection in vitro.