EnhancedIn VivoAirway Gene Transfer via Transient Modification of Host Barrier Properties with a Surface-Active Agent

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Abstract
Effective adenoviral gene therapy requires efficient viral vector entry into epithelial cells. Injured airway epithelia display enhanced gene transfer, reflecting in part increased vector access to protected cell populations and/or protected basolateral membranes. We tested whether adenoviral gene transfer is enhanced by modification of the epithelial barrier in mouse nasal airways with a nonionic detergent (polidocanol, PDOC). In C57BL/6 mice, 1.6 × 109 PFU of Ad5CMV LacZ (AdLacZ) instilled into the right nostril produced negligible gene transfer to the nasal epithelium 2 days after dosing, but significant, dose-dependent increases in gene transfer were achieved by pretreatment with PDOC. Permeation of the electron-dense tracer lanthanum into the intercellular junctions of PDOC (0.1%)-treated murine nasal epithelium, but not into intercellular junctions of vehicle controls, is consistent with PDOC-mediated increases in tight junctional permeability. In CF(–/–) mice, significant gene expression was not detectable after exposure to Ad5CBCFTR alone (1.4 × 109 PFU in 20 μl; AdCFTR), but PDOC pretreatment prior to AdCFTR instillation produced functional expression of CFTR (measured as ΔPD) 5 days after instillation. Because the development and testing of lung gene therapy will principally occur in children and adults with airway disease, AdLacZ gene transfer with and without PDOC pretreatment was examined in infected nasal airways. Gene expression was significantly reduced in infected as compared with uninfected airways. We conclude that the use of adjuvant surface-active and/or membrane-perturbing agents, synthetic or naturally derived, may provide a novel approach to enhancing the efficiency of adenoviral gene transfer. The poor efficiency of airway gene therapy in vivo is one factor limiting progress toward the use of gene therapy in CF. Adjuvant agents that enhance the efficiency of current vectors may help overcome this limitation. We report that a surface-active agent, polidocanol, transiently permeabilizes epithelial cell tight junctions and improves the level of in vivo adenoviral gene transfer of a reporter gene and of CFTR in mouse nasal airway epithelium. In the search for effective in vivo gene transfer vectors, transient modifiers of host epithelium barrier properties may increase the penetration of vectors into the epithelium to increase efficiency, reducing the need for administration of high titers of adenoviral vector.