Transient in utero expression of CFTR does not improve survival of CF knockout mice

Abstract

Lentiviral (LV) vectors can transduce slowly dividing cells such as those of the airway epithelium, the recognised target of CF lung disease. However, efficient LV-mediated transduction of airway epithelial cells is hampered by extra-cellular barriers. Thus, the local confinement on the cell surface of LV vectors is an important requirement for gene delivery to the airway epithelium. To address this issue we have exploited the magnetofection technique in in vitro models of airway epithelium applying a LV vector carrying the Green Fluorescent Protein (GFP) gene. Magnetofectins were formed by non-covalent interaction between LV particles and polycation-coated iron oxide nanoparticles. Bronchial 16HBE14oand bronchiolar H441 cells were tranduced with magnetofectins in the presence of a magnetic field. Magnetofectins were more efficient than LV alone up to 3.9 fold and magnetofection was able to significantly increase the percentage of transduced cells already after 15 minutes of incubation. We next asked whether magnetofection could also be efficient in polarised 16HBE14ocells. Magnetofection determined a 3-fold increase of GFP+ cells (up to 10%) as compared with LV alone. Upon treatment with 50 nM dexamethasone, H441 cells can form hemicysts containing fluid, called “domes”, which are relatively resistant to LV-mediated transduction (GFP+ cells = 6%). Magnetofection increased up to 4 fold the transduction efficiency. Conversely, in the absence of magnetic field no significant effect could be observed. We conclude that magnetofection can facilitate LV-mediated transduction of airway epithelial cells by lowering vector dose and reducing incubation time to achieve efficient transduction. Supported by EU: project no. 005213.