(630) Cellular Tropism of Adeno-associated Viral Vector 4 (AAV4) in Human Large and Small Airway Epithelia

Background: Cystic Fibrosis (CF) is a common genetic disease caused by defects in the cystic fibrosis transmembrane conductance regulator (CFTR), a membrane bound channel permeable to both chloride and bicarbonate anions. Morbidity and mortality rates in CF are largely due to lung disease stemming from chronic bacterial colonization and infection in the conducting airways. Delivering a functional CFTR gene to CF small airway cells holds great promise as a treatment for CF lung disease, as pathological and clinical data suggest that the disease is initiated in small airways with a diameter less than 2mm. Adeno-associated virus 4 (AAV4) is a natural AAV serotype and a safe vector with lower immunogenicity than other gene therapy vectors such as adenovirus. Previously in a CF pig model, we demonstrated that AAV4 has greater tropism for pig small airway epithelia compared with large airways. In addition, AAV4 was superior to all other natural AAV serotypes in transducing ITGα6β4+ pig distal lung progenitor cells. However, the cellular tropism of AAV4 in human large and small airways is not clear.

Methods: We used single cell RNAseq analysis to investigate which cell types AAV4 can transduce in human large and small airways cells cultured at the air-liquid interface.

Results: We found that AAV4 can transduce similar cell types in both large and small airways, including ciliated cells, goblet cells. In addition, AAV4 can transduce SCGB3A2⁺ cells in small airways.

Conclusions: These findings support that AAV4 can serve as a suitable viral vector for CF gene therapy to target small airway secretory cells that express majority of CFTR in human small airways.

Acknowledgements: This work was supported by the National Institutes of Health [HL153165-01A1]; the Cystic Fibrosis Foundation [LI19XX0 ]; and the Cystic Fibrosis Research Institute.

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