Polylysine

Abstract: Complexes containing plasmid DNA, transferrin-polylysine conjugates, and polylysine-conjugated peptides derived from the N-terminal sequence of the influenza virus hemagglutinin subunit HA-2 have been used for the transfer of luciferase or beta-galactosidase marker genes to K562 cells, HeLa cells, and BNL CL.2 hepatocytes. These DNA complexes mimic the entry of viruses into cells, as they contain functions for (i) the packaging of the nucleic acid with polylysine, (ii) the attachment to the cell and receptor-mediated endocytosis with transferrin as a ligand, and (iii) the release from endosomes by using membrane-disrupting influenza peptides. The presence of these influenza peptide conjugates in the DNA complexes renders the complexes active in membrane disruption in a liposome leakage assay and results in a substantial augmentation of the transferrin-polylysine-mediated gene transfer.

Abstract: We are developing efficient methods for gene transfer into tissue culture cells. We have previously shown that coupling of a chimeric adenovirus with polylysine allowed the construction of an adenovirus-polylysine-reporter-gene complex that transferred the transporter gene with great efficiency into HeLa cells. We have now explored simpler, biochemical means for coupling adenovirus to DNA/polylysine complexes and show that such complexes yield virtually 100% transfection in tissue culture cell lines. In these methods adenovirus is coupled to polylysine, either enzymatically through the action of transglutaminase or biochemically by biotinylating adenovirus and streptavidinylating the polylysine moiety. Combination complexes containing DNA, adenovirus-polylysine, and transferrin-polylysine have the capacity to transfer the reporter gene into adenovirus-receptor- and/or transferrin-receptor-rich cells.

Abstract: Optically active compounds of the formula ##STR1## wherein n is 1 or 2 and m is 0, 1, 2 or 3 have antiviral activity. Compounds of the formula wherein at least one of the internucleotide phosphorothioate linkages is of the Sp configuration possess increased antiviral activity and/or metabolic stability.

Abstract: DNA/cationic lipid (lipoplexes), DNA/cationic polymer (polyplexes) and DNA/cationic polymer/cationic lipid (lipopolyplexes) electrostatic complexes are proposed as non-viral nucleic acids delivery systems These DNA-nanoparticles are taken up by the cells through endocytosis processes, but the low capacity of DNA to escape from endosomes is regarded as the major limitations of their transfection efficiency Here, we present a current report on a particular class of carriers including the polymers, peptides and lipids, which is based on the exploitation of the imidazole ring as an endosome destabilization device to favour the nucleic acids delivery in the cytosol The imidazole ring of histidine is a weak base that has the ability to acquire a cationic charge when the pH of the environment drops bellow 6 As it has been demonstrated for poly(histidine), this phenomena can induce membrane fusion and/or membrane permeation in an acidic medium Moreover, the accumulation of histidine residues inside acidic vesicles can induce a proton sponge effect, which increases their osmolarity and their swelling The proof of concept has been shown with polylysine partially substituted with histidine residues that has caused a dramatic increase by 3-45 orders of magnitude of the transfection efficiency of DNA/polylysine polyplexes Then, several histidine-rich polymers and peptides as well as lipids with imidazole, imidazolinium or imidazolium polar head have been reported to be efficient carriers to deliver nucleic acids including genes, mRNA or SiRNA in vitro and in vivo More remarkable, histidylated carriers are often weakly cytotoxic, making them promising chemical vectors for nucleic acids delivery