Transgenic ferret models define pulmonary ionocyte diversity and function.

Speciation leads to adaptive changes in organ cellular physiology and creates challenges for studying rare cell-type functions that diverge between humans and mice. Rare cystic fibrosis transmembrane conductance regulator (CFTR)-rich pulmonary ionocytes exist throughout the cartilaginous airways of humans, but limited presence and divergent biology in the proximal trachea of mice has prevented the use of traditional transgenic models to elucidate ionocyte functions in the airway. Here we describe the creation and use of conditional genetic ferret models to dissect pulmonary ionocyte biology and function by enabling ionocyte lineage tracing (FOXI1-Cre::ROSA-TG), ionocyte ablation (FOXI1-KO) and ionocyte-specific deletion of CFTR (FOXI1-Cre::CFTR).

Sonic Hedgehog Signaling Is Essential for Pulmonary Ionocyte Specification in Human and Ferret Airway Epithelia.

Pulmonary ionocytes express high levels of cystic fibrosis transmembrane conductance regulator (CFTR), an anion channel that is critical for hydration of the airways and mucociliary clearance. However, the cellular mechanisms that govern ionocyte specification and function remain unclear. We observed that increased abundance of ionocytes in cystic fibrosis (CF) airway epithelium was associated with enhanced expression of Sonic Hedgehog (SHH) effectors.

Detargeting Lentiviral-Mediated CFTR Expression in Airway Basal Cells Using miR-106b.

Lentiviral-mediated integration of a transgene cassette into airway basal cells is a strategy being considered for cystic fibrosis (CF) cell-based therapies. However, expression is highly regulated in differentiated airway cell types and a subset of intermediate basal cells destined to differentiate. Since basal stem cells typically do not express CFTR, suppressing the expression from the lentiviral vector in airway basal cells may be beneficial for maintaining their proliferative capacity and multipotency.