| Abstract
| - Genes can be targeted to hepatocytes in vitro and in vivo by the use of asialoorosomucoid−polylysineconjugates. After systemic application, this nonviral vector is recognized by highly selectiveasialoglycoprotein (AsGP) receptors on the sinusoidal liver cell membrane and is taken up via receptor-mediated endocytosis. As most of the DNA is rapidly transferred to lysosomes where it is degraded,transfection efficiency is low and gene expression transient. To address this problem, we incorporateda pH-dependent synthetic hemolytic peptide derived of the G-protein of Vesicular Stomatitis Virus(VSV) into the gene transfer system, to increase endosomal escape of internalized DNA. Themulticomponent carrier binds DNA in a nondamaging way, is still recognized by the AsGP receptor,and is targeted to the liver in vivo. Injection of DNA complexes containing a luciferase marker generesulted in luciferase expression of 29 000 pg/g liver which corresponded to an increase of a factor of103 overexpression after injection of DNA complexes without endosomolytic peptide. Furthermore,the amount of intact transgene within isolated liver cell nuclei was increased by a factor of 101−102by the use of the multicomponent carriers. These results demonstrate that incorporation of a hemolyticpeptide into a nonviral vector can greatly increase gene expression while retaining cell type targetabilityin vivo.
|
