Gene delivery to respiratory epithelial cells by magnetofection.
BACKGROUND
For the topical application of DNA vector complexes to the airways, specific extracellular barriers play a major role. In particular, short contact time of complexes with the cell surface caused by the mucociliary clearance hinders cellular uptake of complexes. The aim of this study was to evaluate the ability of magnetofection, a technique based on the principle of magnetic drug targeting, to overcome these barriers in comparison with conventional nonviral gene transfer methods such as lipofection and polyfection.


METHODS
Experiments were carried out on permanent (16HBE14o-) and primary airway epithelial cells (porcine and human), and native porcine airway epithelium ex vivo. Transfection efficiency and dose-response relationship of magnetofection were examined by luciferase reporter gene expression. Sedimentation patterns and uptake of gene transfer complexes were characterized by fluorescence and electron microscopy, respectively.


RESULTS
We show that (i) application of a magnetic field allows the magnetofectins to sediment and to enrich at the cell surface within a few minutes, (ii) magnetofection bears an improved dose-response relationship, (iii) magnetofection enhances transfection efficiency in both, permanent and primary airway epithelial cells, and (iv) magnetofection leads to significant transgene expression at very short incubation times in an ex vivo airway epithelium organ model.


CONCLUSIONS
Magnetofection provides a potential novel method, which may overcome fundamental limitations of nonviral gene transfer to the airways. Due to the accelerated enrichment at the cell surface it may be of major interest for in vivo applications, where long-term incubation times at the target tissue are hardly achievable.
Department of Molecular Pneumology, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, D-80337 Munich, Germany.
Soeren W
SW
Gersting
Ulrike
U
Schillinger
James
J
Lausier
Petra
P
Nicklaus
Carsten
C
Rudolph
Christian
C
Plank
Dietrich
D
Reinhardt
Joseph
J
Rosenecker
D000818:Animals; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells; D004848:Epithelium / Q000648:ultrastructure; D018390:Gene Targeting / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D008280:Magnetics; D008854:Microscopy, Electron; D013552:Swine; D014162:Transfection / Q000379:methods*