Background: Although epithelial stem/progenitor cells have been isolated from many parts of the human airway epithelium such as lung and trachea, there is limited information in regard to stem cells in nasal epithelium. The aim of this study was to determine if (1) human nasal epithelial stem/progenitor cells (hNESPCs) can be isolated and propagated in vitro and (2) allogeneic adult primary human fibroblasts can serve as a feeder layer for hNESPCs expansion under serum-free conditions.
Methods: Primary cells taken from inferior turbinate biopsy specimens (n = 3) were enzymically dissociated and plated on either allogeneic human fibroblasts or murine NIH 3T3 fibroblasts, in a chemical-defined medium supplemented with growth factors. Self-renewal, proliferation, and differentiation potential were compared.
Results: The optimized media were capable of supporting the undifferentiated growth and expansion of hNESPCs on both feeder cells. The doubling time and cloning efficiency of hNESPCs cultured on a human feeder layer were comparable with that cultured on 3T3 feeders. Significantly, the hNESPCs on both feeder layers could be cultured for four passages, and they can differentiate into ciliated columnar cells and goblet cells at the air-liquid interface, resembling the in vivo mucociliary airway epithelium.
Conclusion: Our results showed the feasibility of expanding hNESPCs for clinical purpose by using human feeder layer, avoiding components of animal source, while preserving their self-renewal and differentiation potential. This study represents an early step toward a better understanding of hNESPCs, and serum -free media plus human feeder potentially would be an ideal method for making clinical grade hNESPCs on a large scale.