Perfluorochemical Liquid Enhances Adeno-Associated Virus-Mediated Transgene Expression in Lungs

Abstract

Use of adeno-associated virus (AAV) vectors for lung gene therapy is limited, in part, by low levels of AAV-mediated transgene expression in lungs. Generally, less than 1% of total airway and alveolar epithelial cells express transgene activity following vector administration. A means of improving AAV vector delivery could potentially enhance AAV-mediated gene expression in lungs. We have previously demonstrated that use of perfluorochemical (PFC) liquids improved overall levels of adenovirus vector-mediated gene expression as well as distribution of expression in lungs of spontaneously breathing rodents. To evaluate whether use of PFC liquids might similarly enhance AAV-mediated expression, spontaneously breathing rodents received intratracheal instillation of the AAV vectors CWRAP and ARAP4 (2-5 x 10(8) FFU/animal) with or without 10 cc/kg body wt PFC liquid (FC-75, ACROS). Animals were sacrificed 4 weeks later and lungs assessed for overall and in situ alkaline phosphatase (AP) expression. Animals receiving vector alone exhibited scattered sparse in situ activity, predominantly in alveolar epithelium. In contrast, animals receiving vector with FC-75 exhibited increased and more widespread AP expression as well as up to a 26-fold increase in AP activity. These results demonstrate that use of the PFC liquid FC-75 improves overall and in situ AAV-mediated gene expression in rodent lungs.

Current Status of Gene Therapy for Inherited Lung Diseases

“…A significant number of preclinical animal studies have been performed with various serotypes of rAAV delivered to the lung. In rodent animal models, rAAV vectors delivered to the lung have shown promising results (47)(48)(49)(50). Such encouraging results have also been confirmed in larger animal models such as rabbit, sheep, and nonhuman primate (51)(52)(53).…”

Inhalation of Nebulized Perfluorochemical Enhances Recombinant Adenovirus and Adeno-Associated Virus-Mediated Gene Expression in Lung Epithelium

“…In situ alkaline phosphatase activity was detected in mounted cryosections of macaque lungs incubated overnight with 2-dicyclohexylphosphino-2¢,4¢,6¢-triisopropylbiphenyl (XPhos) and nitroblue tetrazolium, using standard techniques (Weiss et al, 2000).…”

Gene Therapy for Cystic Fibrosis Airway Disease- Is Clinical Success Imminent?

“…Importantly, PFC has also been shown to enhance gene transfer in abnormal lungs (Weiss et al, 1999b) suggesting that it may be efficacious in the CF lung. PFC also enhances AAV vector mediated gene delivery [Weiss et al, 2000] and has been shown to be effective in enhancing adenoviral mediated gene delivery to primate lung airways [Weiss et al, 2002a]. PFCs appear to enhance gene delivery by both facilitating vector dispersion and propulsion through the airway, and by transiently permeabilising tight junctions .…”

“…AAV-6 has been shown to efficiently transduce murine airways and to transduce airway epithelial cells more efficiently than AAV-2, a significant advantage for CF gene therapy [Halbert et al, 2001]. AAV-6 also appears to be less immunogenic than AAV-2 in mice Various agents have been shown to enhance airway gene delivery with different AAV vector serotypes including gelling agents (AAV-5) [Sinn et al, 2005], PFC (AAV-2) [Weiss et al, 2000] and proteasome inhibitors (AAV-2) (see previous section for details).…”