Identification of a Proximal Progenitor Population from Murine Fetal Lungs with Clonogenic and Multilineage Differentiation Potential

• Nkx2-1 expression can be used to isolate proximal lung progenitors
• The fetal proximal lung progenitors are distinct from currently known progenitors
• The fetal proximal lung progenitors are clonogenic and self-renewing
• The fetal proximal lung progenitors are multipotent for airway lineages

SummaryLung development-associated diseases are major causes of morbidity and lethality in preterm infants and children. Access to the lung progenitor/stem cell populations controlling pulmonary development during embryogenesis and early postnatal years is essential to understand the molecular basis of such diseases. Using a Nkx2-1mCherry reporter mouse, we have identified and captured Nkx2-1-expressing lung progenitor cells from the proximal lung epithelium during fetal development. These cells formed clonal spheres in semisolid culture that could be maintained in vitro and demonstrated self-renewal and expansion capabilities over multiple passages. In-vitro-derived Nkx2-1-expressing clonal spheres differentiated into a polarized epithelium comprised of multiple cell lineages, including basal and secretory cells, that could repopulate decellularized lung scaffolds. Nkx2-1 expression thus defines a fetal lung epithelial progenitor cell population that can be used as a model system to study pulmonary development and associated pediatric diseases.