title: A composite gene delivery system consisting of polyethylenimine and an amphipathic peptide KALA.
abstract: BACKGROUND
  Animal viruses such as enveloped virus carry multi-functional proteins in the virion that can mediate more than two distinct steps of a gene delivery process during the transfer of viral genome into host cells. We tested if the aspects of the viral gene delivery mechanism could be mimicked by forming composite formulae from multi-functional synthetic gene carriers having complementary action modes.
  
  
  METHODS
  Polyethylenimine (PEI) was chosen as the component responsible for endosome escape and DNA condensation and KALA for cellular entry and DNA condensation. Compact DNA-carrier particles consisting of the core part where DNA chains were tightly condensed by PEI and the outer layer lined with KALA were formulated, characterized and compared with monolithic cationic formulae in terms of gene delivery efficiency and mechanism.
  
  
  RESULTS
  High-level gene expression was observed when C2C12 cells were transfected with DNA that was first partially condensed with PEI and, then, fully with KALA. In these formulae KALA mediated enhanced cellular entry of DNA by facilitating endocytic vesicle formation, while PEI provided an effective endosomolytic capacity. An optimal PEI/KALA formula showed transfection efficiencies better than or comparable to the commercial cationic liposome in various cell types in culture and in vivo.
  
  
  CONCLUSIONS
  Gene delivery by combining the membrane-active property of KALA with the endosomolytic activity of PEI can be more efficient than that by either of the properties alone. It appears that, in these formulae, the predominant role of KALA is to facilitate cellular entry of DNA by providing a fusogenic capability, rather than an endosomolytic activity.
authors.affiliation: Laboratory of Human Genomics, Korea Research Institute of Bioscience and Biotechnology, 52 Eoeun-dong, Yusong-gu, Taejon 305-333, Korea.
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Min
authors.forename: Dong Chul
authors.initials: DC
authors.lastname: Lee
authors.forename: Mi Jung
authors.initials: MJ
authors.lastname: Lim
authors.forename: Hyun Sook
authors.initials: HS
authors.lastname: Park
authors.forename: Dong Min
authors.initials: DM
authors.lastname: Kim
authors.forename: Cheong Weon
authors.initials: CW
authors.lastname: Cho
authors.forename: Do Young
authors.initials: DY
authors.lastname: Yoon
authors.forename: Young Il
authors.initials: YI
authors.lastname: Yeom
mesh_terms: D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D004247:DNA / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006801:Humans; D046911:Macromolecular Substances / Q000737:chemistry*; D051379:Mice; D008810:Mice, Inbred C57BL; D010455:Peptides / Q000235:genetics*; D011094:Polyethyleneimine
chemical_list: D004268:DNA-Binding Proteins; C105114:KALA amphipathic peptide; D046911:Macromolecular Substances; D010455:Peptides; D011094:Polyethyleneimine; D004247:DNA