Topography-dependent gene expression and function of common cell archetypes in large and small porcine airways

The small airways of humans are affected early in several lung diseases. However, because they are relatively inaccessible, little is known about the epithelial cells that line these airways. We performed a single cell RNA-seq census of small and large airways of wild-type pigs and pigs with disrupted cystic fibrosis transmembrane conductance regulator (CFTR) gene. The sequencing data showed that small airway epithelia had similar major cell types as large airways but no ionocytes; moreover, lack of CFTR expression had minimal effect on the transcriptome. Small airway epithelial cells expressed a different transcriptome than large airway cells. Quantitative immunohistochemistry showed that small airway basal cells participate in epithelial barrier function. Finally, sequencing data and in vitro electrophysiologic studies suggest that small airway epithelia have a water and ion transport advantage. Our data highlight the archetypal nature of basal, secretory, and ciliated airway cells with location-dependent gene expression and function.