title: Exploration of peptide motifs for potent non-viral gene delivery highly selective for dividing cells.
abstract: BACKGROUND
  The immunogenicity of viral DNA vectors is an important problem for gene therapy. The use of peptide motifs for gene delivery would largely overcome this problem, and provide a simple, safe and powerful approach for non-viral gene therapy.
  
  
  METHODS
  We explored the functional properties of two motifs: the (Lys)(16) motif (for binding and condensing DNA, and probably also nuclear translocation of plasmids) and the fusogenic peptide motif of influenza virus (for acid-dependent endocytic escape of peptide/DNA particles). The physical properties and gene delivery efficiencies of (Lys)(16)-containing peptides in combination with free fusogenic peptide were evaluated, and compared with a single composite peptide incorporating both moieties. Post-mitotic corneal endothelial cells and growth-arrested HeLa were included, so as not to neglect the question of nuclear translocation of plasmids.
  
  
  RESULTS
  The fusogenic moiety in the composite peptide was able to adopt an alpha-helical configuration unhindered by the (Lys)(16) moiety, and retained acid-dependent fusogenic properties. The composite peptide gave remarkably high levels of gene delivery to dividing cell lines. However, in marked contrast to (Lys)(16)/DNA complexes plus free fusogenic peptide, the composite peptide was completely ineffective for gene delivery to post-mitotic and growth-arrested cells.
  
  
  CONCLUSIONS
  Attachment of the fusogenic peptide to (Lys)(16) appears to block (Lys)(16)-mediated nuclear translocation of plasmid, but not fusogenic peptide mediated endocytic escape. This strengthens the experimental basis for (Lys)(16)-mediated nuclear translocation of plasmids, and provides a single peptide with potent gene delivery properties, restricted to dividing cells. This property is potentially useful in experimental biology and clinical medicine.
authors.affiliation: Department of Clinical Sciences, Guys, Kings and St Thomas School of Medicine, The Rayne Institute, London SE5 9NU, UK.
authors.forename: Alan L
authors.initials: AL
authors.lastname: Parker
authors.forename: Louise
authors.initials: L
authors.lastname: Collins
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Zhang
authors.forename: John W
authors.initials: JW
authors.lastname: Fabre
mesh_terms: D000256:Adenoviridae; D020816:Amino Acid Motifs / Q000235:genetics*; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D045744:Cell Line, Tumor; D002470:Cell Survival; D002942:Circular Dichroism; D004587:Electrophoresis, Agar Gel; D004728:Endothelium, Corneal / Q000378:metabolism; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000235:genetics* / Q000627:therapeutic use; D006801:Humans; D008055:Lipids / Q000737:chemistry*; D008156:Luciferases; D049329:Nanostructures; D010316:Particle Size; D010455:Peptides / Q000235:genetics* / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics / Q000502:physiology; D011094:Polyethyleneimine / Q000378:metabolism*; D011487:Protein Conformation; D011817:Rabbits; D014162:Transfection / Q000379:methods
chemical_list: D008055:Lipids; C086724:Lipofectamine; D010455:Peptides; D011094:Polyethyleneimine; D008156:Luciferases