Novel AAV-mediated gene delivery system corrects CFTR function in pigs.
Am J Respir Cell Mol Biol. 2019 Jun 11;:
Authors: Cooney AL, Thornell IM, Singh BK, Shah VS, Stoltz DA, McCray PB, Zabner J, Sinn PL
Cystic fibrosis (CF) is an autosomal recessive disease caused by a mutant cystic fibrosis transmembrane conductance regulator (CFTR) gene and characterized by chronic bacterial lung infections and inflammation. Complementation with functional CFTR normalizes anion transport across the airway surface. Adeno-associated virus (AAV) is a useful vector for gene therapy because of its low immunogenicity and ability to persist for months to years. However, episomal expression may decrease following cell division and ultimately require readministration. To overcome this, we designed an integrating AAV-based CFTR expressing vector termed PB/AAV carrying CFTR flanked by the terminal repeats (TRs) of the piggyBac transposon. With co-delivery of piggyBac transposase, PB/AAV can integrate into the host genome. Because of the AAV packaging constraints, careful consideration was required to ensure that the vector would package and express its CFTR cDNA cargo. In this short-term study, PB/AAV-CFTR was aerosolized to the airways of CF pigs in the absence of the transposase. Two weeks later, transepithelial Cl- current was restored in freshly excised tracheal and bronchus tissue. Additionally, we observed an increase in tracheal airway surface liquid (ASL) pH and bacterial killing as compared to untreated CF pigs. ASL from primary airway cells cultured from treated CF pigs exhibited increased pH correlating with decreased viscosity. Together, these results show that complementing CFTR in CF pigs with PB/AAV rescues the anion transport defect in a large animal CF model. Delivery of this integrating viral vector system to airway progenitor cells could lead to persistent, life-long expression in vivo.
PMID: 31184507 [PubMed – as supplied by publisher]