CFTR gene transfer with AAV improves early cystic fibrosis pig phenotypes
Benjamin Steines, … , David V. Schaffer, Joseph Zabner
Benjamin Steines, … , David V. Schaffer, Joseph Zabner
Published September 8, 2016
Citation Information: JCI Insight. 2016;1(14):e88728. https://doi.org/10.1172/jci.insight.88728.
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Research Article Pulmonology

CFTR gene transfer with AAV improves early cystic fibrosis pig phenotypes

Abstract

The physiological components that contribute to cystic fibrosis (CF) lung disease are steadily being elucidated. Gene therapy could potentially correct these defects. CFTR-null pigs provide a relevant model to test gene therapy vectors. Using an in vivo selection strategy that amplifies successful capsids by replicating their genomes with helper adenovirus coinfection, we selected an adeno-associated virus (AAV) with tropism for pig airway epithelia. The evolved capsid, termed AAV2H22, is based on AAV2 with 5 point mutations that result in a 240-fold increased infection efficiency. In contrast to AAV2, AAV2H22 binds specifically to pig airway epithelia and is less reliant on heparan sulfate for transduction. We administer AAV2H22-CFTR expressing the CF transmembrane conductance regulator (CFTR) cDNA to the airways of CF pigs. The transduced airways expressed CFTR on ciliated and nonciliated cells, induced anion transport, and improved the airway surface liquid pH and bacterial killing. Most gene therapy studies to date focus solely on Cl– transport as the primary metric of phenotypic correction. Here, we describe a gene therapy experiment where we not only correct defective anion transport, but also restore bacterial killing in CFTR-null pig airways.

Authors

Benjamin Steines, David D. Dickey, Jamie Bergen, Katherine J.D.A. Excoffon, John R. Weinstein, Xiaopeng Li, Ziying Yan, Mahmoud H. Abou Alaiwa, Viral S. Shah, Drake C. Bouzek, Linda S. Powers, Nicholas D. Gansemer, Lynda S. Ostedgaard, John F. Engelhardt, David A. Stoltz, Michael J. Welsh, Patrick L. Sinn, David V. Schaffer, Joseph Zabner

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Figure 2

AAV2H22 binds specifically to the apical surfaces of pig airway epithelia.

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AAV2H22 binds specifically to the apical surfaces of pig airway epitheli...
(A and B) AAV2H22 or AAV2 virions were allowed to bind the apical surfaces of pig airway (A) or alveolar (B) epithelia at the indicated doses for 1 hour at 4°C. In airway epithelia, AAV2H22 (blue) plateaued at 6 × 1010 VG, whereas AAV2 (green) did not reach saturation. In alveolar epithelia, both AAV2 and AAV2H22 saturated, but AAV2 had more apparent binding sites. n = 6–12. (C) Consistent with B, AAV2-GFP transduced pig alveolar epithelia more efficiently than AAV2H22-GFP. n = 6; *P < 0.01, Mann-Whitney nonparametric t test. (D) In contrast to pig, AAV2H22-GFP did not infect human airway epithelia. n = 3 from different donors in 4 different experiments; *P < 0.01, Mann-Whitney nonparametric t test.