title: Pseudotyped AAV vector-mediated gene transfer in a human fetal trachea xenograft model: implications for in utero gene therapy for cystic fibrosis.
abstract: BACKGROUND
  Lung disease including airway infection and inflammation currently causes the majority of morbidities and mortalities associated with cystic fibrosis (CF), making the airway epithelium and the submucosal glands (SMG) novel target cells for gene therapy in CF. These target cells are relatively inaccessible to postnatal gene transfer limiting the success of gene therapy. Our previous work in a human-fetal trachea xenograft model suggests the potential benefit for treating CF in utero. In this study, we aim to validate adeno-associated virus serotype 2 (AAV2) gene transfer in a human fetal trachea xenograft model and to compare transduction efficiencies of pseudotyping AAV2 vectors in fetal xenografts and postnatal xenograft controls.
  
  
  RESULTS
  Human fetal trachea or postnatal bronchus controls were xenografted onto immunocompromised SCID mice for a four-week engraftment period. After injection of AAV2/2, 2/1, 2/5, 2/7 or 2/8 with a LacZ reporter into both types of xenografts, we analyzed for transgene expression in the respiratory epithelium and SMGs. At 1 month, transduction by AAV2/2 and AAV2/8 in respiratory epithelium and SMG cells was significantly greater than that of AAV2/1, 2/5, and 2/7 in xenograft tracheas. Efficiency in SMG transduction was significantly greater in AAV2/8 than AAV2/2. At 3 months, AAV2/2 and AAV2/8 transgene expression was >99% of respiratory epithelium and SMG. At 1 month, transduction efficiency of AAV2/2 and AAV2/8 was significantly less in adult postnatal bronchial xenografts than in fetal tracheal xenografts.
  
  
  CONCLUSIONS
  Based on the effectiveness of AAV vectors in SMG transduction, our findings suggest the potential utility of pseudotyped AAV vectors for treatment of cystic fibrosis. The human fetal trachea xenograft model may serve as an effective tool for further development of fetal gene therapy strategies for the in utero treatment of cystic fibrosis.
authors.affiliation: Center for Molecular Fetal Therapy, Division of Pediatric, General, Thoracic and Fetal Surgery, Cincinnati Children's Hospital Medical Center and The University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America. sundeep.keswani@cchmc.org
authors.forename: Sundeep G
authors.initials: SG
authors.lastname: Keswani
authors.forename: Swathi
authors.initials: S
authors.lastname: Balaji
authors.forename: Louis
authors.initials: L
authors.lastname: Le
authors.forename: Alice
authors.initials: A
authors.lastname: Leung
authors.forename: Anna B
authors.initials: AB
authors.lastname: Katz
authors.forename: Foong-Yen
authors.initials: FY
authors.lastname: Lim
authors.forename: Mounira
authors.initials: M
authors.lastname: Habli
authors.forename: Helen N
authors.initials: HN
authors.lastname: Jones
authors.forename: James M
authors.initials: JM
authors.lastname: Wilson
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Crombleholme
mesh_terms: D000818:Animals; D003550:Cystic Fibrosis / Q000235:genetics / Q000628:therapy*; D000229:Dependovirus / Q000235:genetics; D046128:Fetal Therapies / Q000379:methods*; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D014132:Trachea / Q000196:embryology / Q000637:transplantation*; D014183:Transplantation, Heterologous / Q000379:methods*