title: Lactosylated polyethylenimine for gene transfer into airway epithelial cells: role of the sugar moiety in cell delivery and intracellular trafficking of the complexes.
abstract: BACKGROUND
  As we have previously shown that lactosylated polyethylenimine (PEI) is the most efficient glycosylated PEI for gene transfer into human airway epithelial cells in primary culture, we have studied here the role of the lactose residue in the enhancement of gene transfer efficiency observed with lactosylated PEI as compared with unsubstituted PEI in immortalized (Sigma CFTE29o- cells) and primary human airway epithelial cells.
  
  
  RESULTS
  After three transfections of 1 h performed daily, 60% of Sigma CFTE29o- cells were transfected with lactosylated PEI, whereas 25% of cells were transfected with unsubstituted PEI (p < 0.05). Cell viability was 1.8-fold greater with lactosylated PEI as compared with unsubstituted PEI (p < 0.05). As assessed by flow cytometry, the cellular uptake of lactosylated complexes was greater than that of complexes made with unsubstituted PEI (p < 0.05) and involved mostly a receptor-mediated endocytosis. The study of the intracellular trafficking in airway epithelial cells of complexes showed an endosomal and lysosomal accumulation of lactosylated complexes. In the presence of a proton pump inhibitor, the level of lactosylated and unsubstituted PEI-mediated gene expression was reduced more than 20-fold, whereas the cell viability increased to almost 100%. For both complexes, a nuclear localization was observed for less than 5% of intracellular complexes.
  
  
  CONCLUSIONS
  Our results show that the greater gene transfer efficiency observed for lactosylated complexes may be attributed to a higher amount of lactosylated complexes incorporated by airway epithelial cells and a lower cytotoxicity that might be related to reduced endosomolytic properties. However, the lactose residues substituting the PEI did not promote the entry of the plasmid into the nucleus.
authors.affiliation: Laboratoire de Physiologie Respiratoire, IFR Alfred Jost, CHU Cochin, AP-HP-Université Paris V, Paris, France. grosse@cochin.inserm.fr
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Grosse
authors.forename: Yolande
authors.initials: Y
authors.lastname: Aron
authors.forename: Isabelle
authors.initials: I
authors.lastname: Honoré
authors.forename: Guiti
authors.initials: G
authors.lastname: Thévenot
authors.forename: Claire
authors.initials: C
authors.lastname: Danel
authors.forename: Annie-Claude
authors.initials: AC
authors.lastname: Roche
authors.forename: Michel
authors.initials: M
authors.lastname: Monsigny
authors.forename: Isabelle
authors.initials: I
authors.lastname: Fajac
mesh_terms: D001692:Biological Transport; D001980:Bronchi / Q000378:metabolism; D002460:Cell Line; D011992:Endosomes / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D005434:Flow Cytometry; D015870:Gene Expression; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins; D006801:Humans; D007785:Lactose / Q000031:analogs & derivatives* / Q000737:chemistry; D008156:Luciferases / Q000032:analysis / Q000235:genetics; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D008247:Lysosomes / Q000378:metabolism; D018942:Macrolides / Q000494:pharmacology; D010957:Plasmids / Q000008:administration & dosage / Q000378:metabolism; D011094:Polyethyleneimine / Q000031:analogs & derivatives* / Q000737:chemistry; D020545:Respiratory Mucosa / Q000378:metabolism*; D014162:Transfection / Q000379:methods*
chemical_list: D008164:Luminescent Proteins; D018942:Macrolides; D049452:Green Fluorescent Proteins; C040929:bafilomycin A1; D011094:Polyethyleneimine; D008156:Luciferases; D007785:Lactose