title: Characterization and transfection properties of lipoplexes stabilized with novel exchangeable polyethylene glycol-lipid conjugates.
abstract: The positive charge of cationic-lipid/DNA complexes (lipoplexes) renders them highly susceptible to interactions with the biological milieu, leading to aggregation and destabilization, and rapid clearance from the blood circulation. In this study we synthesized and characterized a set of novel amphiphiles, based on N-methyl-4-alkylpyridinium chlorides (SAINTs), to which a PEG moiety is coupled. Plasmids were fully protected in lipoplexes prepared from cationic SAINT-2 lipid and stabilized with SAINT-PEGs. Our results demonstrate that SAINT-PEG stabilization is transient, and permits DNA to be released from these lipoplexes. The rate of SAINT-PEG transfer from lipoplexes to acceptor liposomes was determined by the nature of the lipid anchor. Increased hydrophobicity, by lengthening the alkyl chain, resulted in a decrease of the rate of DNA release from the lipoplexes. Chain unsaturation had the opposite effect. Similarly, the in vitro transfection potency of lipoplexes containing PEG-SAINT derivatives was sensitive to the length and (un)saturation of the alkyl chain. However, the internalization of SAINT-PEG stabilized lipoplexes is determined by their charge, rather than by the concentration of the polymer conjugate. Lipoplexes targeted to cell-surface epithelial glycoprotein 2, by means of a covalently coupled monoclonal antibody, were specifically internalized by cells expressing this antigen.
authors.affiliation: Department of Membrane Cell Biology, University of Groningen, A Deusinglaan 1, 9713 AV Groningen, The Netherlands.
authors.forename: Joanna
authors.initials: J
authors.lastname: Rejman
authors.forename: Anno
authors.initials: A
authors.lastname: Wagenaar
authors.forename: Jan B F N
authors.initials: JB
authors.lastname: Engberts
authors.forename: Dick
authors.initials: D
authors.lastname: Hoekstra
mesh_terms: D000818:Animals; D002412:Cations; D018736:DNA Adducts / Q000737:chemistry*; D018390:Gene Targeting; D008055:Lipids / Q000138:chemical synthesis*; D008081:Liposomes; D008546:Melanoma, Experimental; D051379:Mice; D018613:Microscopy, Confocal; D010714:Phosphatidylethanolamines / Q000737:chemistry; D010957:Plasmids; D011092:Polyethylene Glycols / Q000737:chemistry*; D011726:Pyridinium Compounds / Q000138:chemical synthesis*; D014162:Transfection / Q000379:methods
chemical_list: C410262:1,2-dioleoyl-glycero-3-phosphatidyl ethanolamine; D002412:Cations; D018736:DNA Adducts; D008055:Lipids; D008081:Liposomes; D010714:Phosphatidylethanolamines; D011726:Pyridinium Compounds; C414306:SAINT 2; D011092:Polyethylene Glycols