Airway-to-Go: An Ex Vivo Cystic Fibrosis Airway Model and Bioreactor System for High Throughput Gene Therapy Screening

Despite three decades of progress since the cystic fibrosis transmembrane conductance regulator (CFTR) gene was discovered, there is still no gene therapeutic cure for the lethal pulmonary component of cystic fibrosis (CF). Existing CF models fall short of capturing all aspects of CF lung disease: animal models either develop gastrointestinal-only disease or are prohibitively expensive for large-scale experiments, while cell culture models lack both 3D tissue context and the thick inflammatory exudate barrier to airway-side delivery. To maximize translational potential, CF gene therapeutics must be tested on a model that captures all genotypic and phenotypic aspects of CF lung disease. Here, we combine three key innovations─(i) a grab-and-go, real-time, imaging-enabled bioreactor, (ii) an optimized tissue culture protocol for human and porcine airway explants, and (iii) a biophysical-bioelectrical barrier model of CF─to build the Airway-to-Go, a platform uniquely suited to high-throughput screening of candidate gene therapies for CF. Our air-liquid interface bioreactor design provides an even distribution of nebulized material and interfaces with a range of nondestructive monitoring technologies, including bioluminescence imaging, bioimpedance monitoring, and fluorescence microscopy in two planes. A Pneumacult-based tissue culture method enabled by new tissue holders supports both porcine and human CF airway explant structure and function for as long as 10 weeks. Disease model components that mimic the bioelectrical (via CFTR inhibition) and biophysical (via bioartificial mucus addition) barriers to gene delivery influence tissue inflammatory state and gene uptake, without causing toxicity. When these components were combined for a demonstrative gene delivery study using viral vectors, nondestructive readouts of gene delivery success revealed differences in gene uptake and expression due to CF-mimetic biophysical and bioelectrical barriers. This work establishes a built-for-purpose platform to accelerate translation of CF gene therapeutics, using porcine and human tissue explants as a steppingstone to clinical trials.