Ferret Glandular Myoepithelial Cells Are Multipotent Airway Progenitors with a Secretory Lineage Bias.

BACKGROUND

Airway submucosal glands (SMGs) play a key role in pulmonary defense by producing mucus and antimicrobial secretions; their dysfunction underlies diseases such as cystic fibrosis (CF) and chronic obstructive pulmonary disease. Murine studies have identified tracheal glandular myoepithelial cells (GMECs) as reserve stem cells, but CFTR-deficient mice lack the intrapulmonary airway glands required to model CF lung disease. In contrast, CFTR-deficient ferrets possess intrapulmonary airway glands, thereby closely recapitulating human CF lung pathology, yet we currently lack models to trace these cells in vivo.

METHODS

We generated an ACTA2  CreER::ROSA  mTmG transgenic ferret model to lineage-trace ACTA2-expressing GMECs. We examined GMEC contributions to glandular development and surface airway epithelium (SAE) regeneration following polidocanol injury. Single-cell transcriptomics, organoid, and air-liquid interface (ALI) cultures were utilized to evaluate epithelial differentiation and CFTR-mediated ion transport.

RESULTS

Single-cell trajectory models and lineage tracing revealed that ferret GMECs are high-potency multipotent progenitors contributing to the basal, serous, and mucous lineages during gland development. After severe adult airway injury, GMECs recruited to the SAE and regenerated multiple epithelial cell types with a bias towards secretory cells. Despite robust FOXI1+ ionocyte formation, GMEC-derived epithelia exhibited reduced CFTR expression, function, and fluid secretion compared to non-GMEC-derived glandular epithelia.

CONCLUSIONS

Ferret GMECs are multipotent progenitors and contribute to gland development and airway repair. However, their descendants demonstrate bias toward the specification of secretory cells and CFTRLow ionocytes. This suggests that GMEC-driven repair may result in structurally restored yet functionally compromised epithelia, potentially contributing to mucus retention in muco-obstructive airway diseases.