Impact of ATP-binding cassette A3 (ABCA3) mutations on alveolar type 2 cell function and genetic complementation

Summary/Abstract Pulmonary surfactant is comprised of phospholipids and protein components and helps prevent lung collapse by lowering surface tension in alveolar lining fluid. ATP-binding cassette A3 (ABCA3) is a cyclic AMP-activated phospholipid transporter that localizes to the limiting membrane of lamellar bodies in alveolar type 2 epithelial cells (AEC2s). Genetic variants in

ABCA3 can cause severe neonatal respiratory distress syndrome (RDS) or later onset pulmonary fibrosis and are the most common genetic causes of childhood interstitial lung diseases (chILD). Other than lung transplant, there are no specific treatments for severe cases of ABCA3 deficiency. Since ABCA3 deficiency is autosomal recessive, it should be amenable to

gene addition strategies. Complementing the loss of function with a full length ABCA3 cDNA reverses surfactant deficiency phenotypes in vitro. Our overall goals are to 1) understand the biological effects of ABCA3 mutations in human AEC2s and 2) actualize a gene therapy strategy to modify the disease course by efficiently and persistently expressing ABCA3 at

physiological levels in AEC2s.