(679) Transduction of Ferret Airway, Liver and Pancreas Following a Single Dose of AAV1

Background: The major hurdle with gene therapy is the transduction of sufficient CFTR to be therapeutic without adverse events. One way to show definitively that gene therapy can be therapeutic is to rescue defective CFTR function in a relevant animal model that recapitulates, as closely as possible, human disease ([1]). The ferret model has undergone extensive development into a highly useful disease model in animals bearing mutations in CFTR such as G551D and F508-del [2]. Demonstration that a gene therapeutic approach can ameliorate disease in these ferrets would be an advance. Thus, the goal here is to assess whether dosing of AAV1-CFTR vectors administered to young ferrets leads to widespread gene transfer and expression. Although an excellent model for studying CF pathophysiology, a recent study found that an inhibitory substance is present in the airway which may alter the transduction of ferret airways by AA1 [3].

Methods: To test whether we can overcome this potential barrier, we sprayed into the airways of male and female 5-week-old ferrets 1 dose of 10¹¹ vg of AAV1-GFP, one male and one female was kept as controls.

Results: AAV1-GFP was detectable at ≥10⁶ vg/ug genomic DNA in trachea, lung, liver and pancreas. mRNA expression was detected at ≥10⁵ copies/ug genomic DNA in trachea, lung, and liver and 10⁴ copies/ug genomic DNA in pancreas. Widespread immunostaining and protein expression were seen in the tissues of both animals.

Conclusions: GFP protein expression following a single dose of AAV1-GFP suggests that transduction by AAV1 based vectors occurs in airways, liver and pancreas of normal ferrets. Given that CF is a multiorgan disease, transduction of liver and pancreas and perhaps the GI tract following lung delivery may be an added benefit for multiorgan rescue of CFTR.

Acknowledgements: Funded by NHLBI R0122267 and NIDDK R01126778.

References: [1] McCarron A, Parsons D, Donnelley M. Animal and cell culture models for cystic fibrosis: which model is right for your application? The American Journal of Pathology 2021;191(2):228-42.

[2] Liu X, Luo M, Guo C, Yan Z, Wang Y, Engelhardt JF. Comparative biology of rAAV transduction in ferret, pig and human airway epithelia. Gene Ther 2007;14(21):1543-8.

[3] Yan Z, Sun X, Evans IA, Tyler SR, Song Y, Liu X, Sui H, Engelhardt JF. Postentry processing of recombinant adeno-associated virus type 1 and transduction of the ferret lung are altered by a factor in airway secretions. Hum Gene Ther 2013;24(9):786-96.