Distal airway stem cells yield alveoli in vitro and during lung regeneration following H1N1 influenza infection (LCM_Four populations of cells). Mus musculus

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: H1N1 infected mice were sacrificed at 25 dpi and the lungs were snap frozen and embedded in OCT. Sections were cut and stained for several markers and consecutive sections were used for Laser Capture Microdissection.The PALM® Robot Microbeam laser microdissection system (P.A.L.M. GmbH, Bernried, Germany) in combination with a Zeiss microscope was used to dissect out desired cells.Four population of cells were collected namely alveoli, Krt5+,Spc+ and K5&SPC-. Isolated cells were collected in adhesive caps (Carl Zeiss, Inc.) and RNA was extracted using the Pico Pure RNA extraction kit (Arcturus).