Conditional reprogramming of pediatric airway epithelial cells: A new human model to investigate early-life respiratory disorders

Background: Airway epithelial cells (AEC) are quite difficult to access in newborns and infants. It is critically important to develop robust life-extended models to conduct translational studies in this age group. We propose the use of a recently described cell culture technology (conditionally reprogrammed cells-CRC) to generate continuous primary cell cultures from nasal and bronchial AEC of young children. Methods: We collected nasal and/or bronchial AEC from a total of 23 subjects of different ages including newborns/infants/toddlers (0-2years; N=9), school-age children (4-11years; N=6), and a group of adolescent/adult donors (N=8). For CRC generation, we used conditioned medium from mitotically inactivated 3T3 fibroblasts and Rho-associated kinase (ROCK) inhibitor (Y-27632). Antiviral immune responses were studied using 25 key antiviral genes and protein production of type III epithelial interferon (IFN lambda 1) after double-stranded (ds) RNA exposure. Results: CRC derived from primary AEC of neonates/infants and young children exhibited: (i) augmented proliferative capacity and life extension, (ii) preserved airway epithelial phenotype after multiple passages, (iii) robust immune responses characterized by the expression of innate antiviral genes and parallel nasal/bronchial production of IFN lambda 1 after exposure to dsRNA, and (iv) induction of airway epithelial inflammatory and remodeling responses to dsRNA (eg, CXCL8 and MMP9). Conclusion: Conditional reprogramming of AEC from young children is a feasible and powerful translational approach to investigate early-life airway epithelial immune responses in humans.