Lineage-negative progenitors mobilize to regenerate lung epithelium after major injury

Lineage-tracing experiments identify a rare, undifferentiated population of quiescent cells in the mouse distal lung that are activated through a Notch signalling pathway to repair the epithelium after bleomycin- or influenza-mediated injury; inappropriate Notch signalling may be a major contributor to failed regeneration within the lungs of patients with chronic lung disease.