Multiparametric image analysis of lung‐branching morphogenesis

BACKGROUND: Lung-branching morphogenesis is a fundamental developmental process, yet the cellular dynamics that occur during lung development and the molecular mechanisms underlying recent postulated branching modes are poorly understood. RESULTS: Here, we implemented a time-lapse video microscopy method to study the cellular behavior and molecular mechanisms of planar bifurcation and domain branching in lung explant- and organotypic cultures. Our analysis revealed morphologically distinct stages that are shaped at least in part by a combination of localized and orientated cell divisions and by local mechanical forces. We also identified myosin light-chain kinase as an important regulator of bud bifurcation, but not domain branching in lung explants. CONCLUSIONS: This live imaging approach provides a method to study cellular behavior during lung-branching morphogenesis and suggests the importance of a mechanism primarily based on oriented cell proliferation and mechanical forces in forming and shaping the developing lung airways.