Potentiation of Gene Transfer to the Mouse Lung by Complexes of Adenovirus Vector and Polycations Improves Therapeutic Potential

Abstract

Recombinant adenovirus (Ad) vectors are being considered for in vivo delivery of various therapeutic genes. One limiting factor in the development of Ad-based gene therapy is the low efficiency of gene transfer to target tissues such as vascular endothelium, smooth muscle, and airway epithelium. Complexing Ad vector with various polycations has been shown to enhance transduction of cell lines otherwise resistant to Ad infection in vitro. On the basis of this observation, the activity of Ad/polycation complexes was tested in vivo in the mouse lung. The results indicated that several polycations were capable of enhancing transduction of mouse respiratory epithelium, leading to a 1-2 log increase in levels of transgene expression. Poly-L-lysine (PLL) and DEAE-dextran were examined further and were found to increase Ad-mediated gene transfer without any additional toxicity as assessed histologically or through the measurement of inflammatory cytokines in bronchoalveolar lavages. The two polycations also failed to affect the humoral response against Ad vector and were themselves nonimmunogenic under conditions leading to enhanced gene transfer. Moreover, the ability to use reduced doses of vector complexed with polycations resulted in lower levels of Ad-specific antibodies and, thereby, improved readministration of vector. These results suggest that complexing Ad vectors with polycations has the potential to improve the therapeutic index by increasing transgene expression while reducing unwanted responses associated with high doses of vector.

Anti-inflammatory gene therapy directed at the airway epithelium

“…18 The virus has an E1 deletion and carries the porcine I B␣ cDNA in combination with the SV40 large T antigen nuclear localization signal (NLS). An E1-deleted adenovirus expressing nuclear localized ␤-galactosidase 35 was used as a control virus. Purification of the recombinant adenovirus was carried out using two consecutive cesium chloride centrifugations, as previously described.…”

Transgene expression is increased by photochemically mediated transduction of polycation-complexed adenoviruses

“…[6][7][8] One strategy for obtaining CAR-independent entry in Ad5-resistant cells is to make noncovalent complexes of adenovirus (Ad) with cationic agents. [9][10][11][12][13][14][15][16] The cationic components can associate with the Ad particles due to the net negative viral surface charge, and hence, the attachment to the negatively charged cell membrane is facilitated. This method enables potent gene delivery via CAR-independent cell infection, demonstrating that the interaction with the primary receptor is not crucial for cellular entry.…”

“…This method enables potent gene delivery via CAR-independent cell infection, demonstrating that the interaction with the primary receptor is not crucial for cellular entry. 9,12 Increased viral uptake and transgene expression due to the use of cationic polymers has been reported in airway epithelia in vitro 9 and in vivo, 11 as well as in cultured smooth muscle cells 12 and in tumor cells. 13 As the fiber-CAR interaction largely determines cell tropism for native Ad5, fiberless particles have been constructed to abrogate all interaction with the primary receptor.…”

Evaluation of Cell-Penetrating Peptide/Adenovirus Particles for Transduction of CAR-Negative Cells

“…One promising approach involves genetic modification of the fiber/knob and capsid proteins to insert small peptides, such as RGD, that enhance CAR-independent translocation (Vigne, Mahfouz et al 1999;Ogawara, Rots et al 2004;Kreppel, Gackowski et al 2005 9 alternative approach to genetic modification that allows a wide range of amino acids in the capsid to be modified with polymers (e.g., PEG or PLL) or peptides after conventional production and purification of the virus (Kaplan, Pennington et al 1998).…”