The best-laid schemes o’ mice an’ men
Gang aft agley,
An’ lea’e us nought but grief an' pain,
For promis’d joy!
Still thou are blest, compared wi’ me!
The present only toucheth thee:
But och! I backward cast my e’e,
On prospects drear!
An’ forward, tho’ I canna see,
I guess an’ fear!
Excerpt from “To a Mouse” by Robert Burns
Two recent studies have provided new insights into the cellular identity and preferred regenerative schemes of progenitor cells in mouse and human airways [1, 2]. These findings not only have important implications for disease progression, but may also help scientists develop new techniques for improving human airway regeneration.
Schemes of homeostasis and repair
The mouse trachea is lined by basal, secretory and ciliated cells. Previous genetic lineage tracing studies have shown that in the homeostatic and repairing mouse trachea, basal cells are widespread, multipotent progenitor cells capable of both long-term self-renewal and differentiation into ciliated and secretory cells [3, 4]. Similar experiments have also shown that differentiated tracheal club cell (Clara cell) secretory protein (CCSP)-expressing cells can also self renew and give rise to ciliated cells, but that these do not play a major role in tracheal homeostasis [5]. In a recent publication, Tata et al. [1] found that murine airways exhibit an unexpected cellular plasticity in response to genetically mediated basal progenitor cell ablation. Lineage labelling showed that tracheal CCSP-expressing cells can differentiate into fully functional basal cells competent to act as epithelial progenitors. This alternate strategy of CCSP-expressing cell-mediated repair of the tracheal epithelium …