Clonal Dynamics Reveal Two Distinct Populations of Basal Cells in Slow Turnover Airway Epithelium

Watson et al., 2015, Cell Reports 12, pp 90-101

July 7, 2015  

http://dx.doi.org/10.1016/j.celrep.2015.06.011

Summary

The Rawlins and Simons groups have collaborated to investigate the steady-state, slow turnover of cells lining the mouse trachea to find out how the different mature cell types are generated from the adult stem cells. It is already known that human cells have a very similar cell lineage to mouse trachea, but the details of the hierarchy are easier to explore in the mouse. The cell population includes basal cells and luminal secretory cells and ciliated cells. 

Using clonal lineage labelling, mathematical modelling, and single-cell molecular analysis, the team have shown that the mouse tracheal epithelium contains two major, equally distributed subpopulations of basal cells: stem cells and long-lived precursors that are already committed to differentiation. These two cell types are morphologically identical.  The precursors mature after 11 days into luminal secretory cells, which are short-lived and self renewing, and which are the major steady-state source of new ciliated cells.

Having two populations of basal cells, one committed to differentiation yet morphologically identical to the stem cells, is an unexpected mechanism of epithelial maintenance in a slow-turnover tissue.  The model presents a new experimental and theoretical foundation for studies of airway homeostasis, injury and disease.

Image reproduced from the paper under Creative Commons CC-BY license.