Distal airway stem cells yield alveoli in vitro and during lung regeneration following H1N1 influenza infection (stem cell clones NESC,TASC,DASC). Homo sapiens

The extent of lung regeneration following catastrophic damage and the potential role of adult stem cells in such a process remains obscure. Sublethal infection of mice with an H1N1 influenza virus related to that of the 1918 pandemic triggers massive airway damage followed by apparent regeneration. We show here that p63-expressing stem cells in the bronchiolar epithelium undergo rapid proliferation after infection and radiate to interbronchiolar regions of alveolar ablation. Once there, these cells assemble into discrete, Krt5+ pods and initiate expression of markers typical of alveoli. Gene expression profiles of these pods suggest that they are intermediates in the reconstitution of the alveolar-capillary network eradicated by viral infection. The dynamics of this p63-expressing stem cell in lung regeneration mirrors our parallel findings that defined pedigrees of human distal airway stem cells assemble alveoli-like structures in vitro and suggests new therapeutic avenues to acute and chronic airway disease. Overall design: The long-term self-renewal potential of the putative human stem cell clones (NESC,TASC,DASC) allowed us to isolate independent pedigrees for the analysis of the progeny of a single cell. Expansion of these lines yielded abundant immature cells of known pedigree for a range of differentiation assays to assess lineage potential. All stem cells were grown on feeder layer (3T3).NESC were differentiated using Air liquid interface system (ALI), 3D matrigel system (MAT) and Self assembling sphere culture(SAS). The differentiation potential of TASC and DASC were studied using ALI and MAT systems.