title: Full deacylation of polyethylenimine dramatically boosts its gene delivery efficiency and specificity to mouse lung.
abstract: High-molecular-mass polyethylenimines (PEIs) are widely used vectors for nucleic acid delivery. We found that removal of the residual N-acyl moieties from commercial linear 25-kDa PEI enhanced its plasmid DNA delivery efficiency 21 times in vitro, as well as 10,000 times in mice with a concomitant 1,500-fold enhancement in lung specificity. Several additional linear PEIs were synthesized by acid-catalyzed hydrolysis of poly(2-ethyl-2-oxazoline), yielding the pure polycations. PEI87 and PEI217 exhibited the highest efficiency in vitro: 115-fold and 6-fold above those of the commercial and deacylated PEI25s, respectively; moreover, PEI87 delivered DNA to mouse lung as efficiently as the pure PEI25 but at a lower concentration and with a 200-fold lung specificity. These improvements stem from an increase in the number of protonatable nitrogens, which presumably results in a tighter condensation of plasmid DNA and a better endosomal escape of the PEI/DNA complexes. As a validation of the potential of such linear, fully deacylated PEIs in gene therapy for lung diseases, systemic delivery in mice of the complexes of a short interfering RNA (siRNA) against a model gene, firefly luciferase, and PEI25 or PEI87 afforded a 77% and 93% suppression of the gene expression in the lungs, respectively. Furthermore, a polyplex of a siRNA against the influenza viral nucleocapsid protein gene and PEI87 resulted in a 94% drop of virus titers in the lungs of influenza-infected animals.
authors.affiliation: Department of Chemistry and Division of Biological Engineering, Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Mini
authors.initials: M
authors.lastname: Thomas
authors.forename: James J
authors.initials: JJ
authors.lastname: Lu
authors.forename: Qing
authors.initials: Q
authors.lastname: Ge
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Zhang
authors.forename: Jianzhu
authors.initials: J
authors.lastname: Chen
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Klibanov
mesh_terms: D000215:Acylation; D000818:Animals; D045744:Cell Line, Tumor; D005786:Gene Expression Regulation; D018014:Gene Transfer Techniques; D006801:Humans; D007251:Influenza, Human / Q000188:drug therapy / Q000235:genetics; D008168:Lung / Q000378:metabolism*; D051379:Mice; D009975:Orthomyxoviridae / Q000187:drug effects / Q000378:metabolism; D011094:Polyethyleneimine / Q000737:chemistry* / Q000378:metabolism* / Q000627:therapeutic use; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D034741:RNA, Small Interfering; D011094:Polyethyleneimine