title: Effects of cell-penetrating peptides and pegylation on transfection efficiency of polyethylenimine in mouse lungs.
abstract: BACKGROUND
  Cell-penetrating peptides (CPPs) could potentially be used as vectors for intracellular delivery of proteins, peptides and nucleic acids. The present study examined different CPPs, such as TAT-derived and arginine rich sequences, as well as model amphiphilic peptide, with respect to transfection efficiency of pegylated polyethylenimine (PEI) in A549, Calu-3 cells and in mice after intra-tracheal administration.
  
  
  METHODS
  The conjugates were prepared by the coupling of CPPs to PEI via a heterobifunctional polyethylene glycol (PEG) linker, resulting in the bioconjugates CPP-PEG-PEI. Structures were successfully confirmed by (1)H-nuclear magnetic resonance and diffusion-ordered spectroscopy. Unmodified PEI 25 kDa was compared with pegylated PEI, and aggregation tendency in cell culture medium, interaction with mucin and stability against heparin was assayed. After evaluating transfection efficiency of the polymers in two different lung cell lines, luciferase reporter gene expression was determined in mouse lungs.
  
  
  RESULTS
  All conjugates showed superior transfection efficiency compared to unmodified PEI 25 kDa. The conjugates sizes were generally < 300 nm, thus enabling them to penetrate through the mucus lining of the lung and reach the target cells. Coupling of CPPs to PEG-PEI, however, did not significantly improve transfection efficiency in A549 cells, calu-3 cells and in mouse lungs.
  
  
  CONCLUSIONS
  We show that small and stable polyplex size achieved by pegylation is favourable for successful pulmonary gene delivery. Compared to PEI 25 kDa, pegylated PEI and CPP-PEG-PEI displayed enhanced transfection efficiency both in vitro and in vivo.
authors.affiliation: Department of Pharmaceutics and Biopharmacy, Philipps Universität, Marburg, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Nguyen
authors.forename: Xiulan
authors.initials: X
authors.lastname: Xie
authors.forename: Michael
authors.initials: M
authors.lastname: Neu
authors.forename: Rio
authors.initials: R
authors.lastname: Dumitrascu
authors.forename: Regina
authors.initials: R
authors.lastname: Reul
authors.forename: Johannes
authors.initials: J
authors.lastname: Sitterberg
authors.forename: Udo
authors.initials: U
authors.lastname: Bakowsky
authors.forename: Ralph
authors.initials: R
authors.lastname: Schermuly
authors.forename: Ludger
authors.initials: L
authors.lastname: Fink
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmehl
authors.forename: Tobias
authors.initials: T
authors.lastname: Gessler
authors.forename: Werner
authors.initials: W
authors.lastname: Seeger
authors.forename: Thomas
authors.initials: T
authors.lastname: Kissel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D018014:Gene Transfer Techniques; D005822:Genetic Vectors / Q000008:administration & dosage; D008168:Lung / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D018625:Microscopy, Atomic Force; D008969:Molecular Sequence Data; D010455:Peptides / Q000008:administration & dosage / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011094:Polyethyleneimine / Q000008:administration & dosage / Q000737:chemistry*; D014162:Transfection
chemical_list: D010455:Peptides; D011092:Polyethylene Glycols; D011094:Polyethyleneimine