title: Transfection of multiple pulmonary cell types following intravenous injection of PEI-DNA in normal and CFTR mutant mice.
abstract: BACKGROUND
  The polycationic vector polyethylenimine (PEI) has been shown to be a powerful agent for transfecting the mouse lung after injection of plasmid-based polyplexes through the tail vein. These findings raise therapeutic prospects for a number of lung conditions. For such potentials to be realised, the precise identity of the transfected cells remains to be determined; however, so far, no ultrastructural analysis has been performed on PEI-transfected lungs. The definition of which pulmonary cells are transfected is particularly critical for certain pulmonary diseases which might require transfection of defined cell types such as epithelial cells for cystic fibrosis (CF).
  
  
  METHODS
  Here, we use a combination of light and electron microscopy to determine which cells are transfected in the lung after PEI-mediated gene delivery through the intravenous route. Furthermore, we extend the same experimental setting to a mouse model of CF to provide proof of principle that this approach can be used in genetic models of the disease.
  
  
  RESULTS
  We show that within 18-20 h after injection through the tail vein, DNA/PEI complexes have already crossed the capillary barrier resulting in high levels of expression of reporter genes in the lungs. Transgene expression is observed in endothelial cells, in type I and type II pneumocytes, and in septal cells. Coexpression of the transgene and of the endogenous CF transmembrane conductance regulator (CFTR) gene is observed in some of the targeted epithelial cells. Levels and sites of expression are similar in normal and in CFTR-mutant mice.
  
  
  CONCLUSIONS
  The results demonstrate that PEI-mediated gene delivery leads to transfection of epithelial cells beyond the endothelial barrier and show that this method can be used for lung gene delivery in CF fragile mutant mice.
authors.affiliation: UMR5166 CNRS-MNHN Evolution des Régulations Endocriniennes, 7 rue Cuvier, 75231 Paris Cedex 5, France.
authors.forename: Fariel
authors.initials: F
authors.lastname: Dif
authors.forename: Chakib
authors.initials: C
authors.lastname: Djediat
authors.forename: Olinda
authors.initials: O
authors.lastname: Alegria
authors.forename: Barbara
authors.initials: B
authors.lastname: Demeneix
authors.forename: Giovanni
authors.initials: G
authors.lastname: Levi
mesh_terms: D000818:Animals; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism; D005260:Female; D005822:Genetic Vectors / Q000008:administration & dosage; D007275:Injections, Intravenous / Q000379:methods*; D008156:Luciferases / Q000378:metabolism; D008168:Lung / Q000098:blood supply / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018181:Mice, Inbred CFTR; D011094:Polyethyleneimine / Q000008:administration & dosage* / Q000494:pharmacology; D014162:Transfection / Q000379:methods*; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D011094:Polyethyleneimine; D008156:Luciferases; D001616:beta-Galactosidase