The pH-sensitive translocation of V-ATPase in the small airway of cystic fibrosis pigs.

In contrast to pig large airways, the pH of airway surface liquid (ASL) in pig small airways is regulated by CFTR-mediated HCO secretion and the vacuolar-type H ATPase (V-ATPase) proton secretion. We hypothesized that, in cystic fibrosis (CF), the ASL pH of small airways is acidic, and the V-ATPase is internalized. We quantified proton secretion during the addition of an alkaline test solution by measuring changes in a pH-dependent fluorescent dye generated by porcine small airway epithelia in the absence and presence of bafilomycin A1.

WNK Inhibition Increases Surface Liquid pH and Host Defense in Cystic Fibrosis Airway Epithelia.

In cystic fibrosis (CF), reduced HCO secretion acidifies the airway surface liquid (ASL), and the acidic pH disrupts host defenses. Thus, understanding the control of ASL pH (pH) in CF may help identify novel targets and facilitate therapeutic development. In diverse epithelia, the WNK (with-no-lysine [K]) kinases coordinate HCO and Cl transport, but their functions in airway epithelia are poorly understood.

A Single-Cell Atlas of Large and Small Airways at Birth in a Porcine Model of Cystic Fibrosis.

Lack of CFTR (cystic fibrosis transmembrane conductance regulator) affects the transcriptome, composition, and function of large and small airway epithelia in people with advanced cystic fibrosis (CF); however, whether lack of CFTR causes cell-intrinsic abnormalities present at birth versus inflammation-dependent abnormalities is unclear. We performed a single-cell RNA-sequencing census of microdissected small airways from newborn CF pigs, which recapitulate CF host defense defects and pathology over time. Lack of minimally affected the transcriptome of large and small airways at birth, suggesting that infection and inflammation drive transcriptomic abnormalities in advanced CF.

Transduction of Pig Small Airway Epithelial Cells and Distal Lung Progenitor Cells by AAV4.

Cystic fibrosis (CF) is caused by genetic mutations of the CF transmembrane conductance regulator (CFTR), leading to disrupted transport of Cl and bicarbonate and CF lung disease featuring bacterial colonization and chronic infection in conducting airways. CF pigs engineered by mutating CFTR develop lung disease that mimics human CF, and are well-suited for investigating CF lung disease therapeutics. Clinical data suggest small airways play a key role in the early pathogenesis of CF lung disease, but few preclinical studies have focused on small airways.

Lack of airway submucosal glands impairs respiratory host defenses.

Submucosal glands (SMGs) are a prominent structure that lines human cartilaginous airways. Although it has been assumed that SMGs contribute to respiratory defense, that hypothesis has gone without a direct test. Therefore, we studied pigs, which have lungs like humans, and disrupted the gene for ectodysplasin (), which initiates SMG development.