Clawing Your Way Back: Why Nails Are So Important

The distal tips of mammalian digits can regenerate following amputation, but only when the nail apparatus is intact. Coordinated regrowth of nail and distal phalanx involves nail epithelial cells and undifferentiated mesenchymal cells that form the “blastema,” which subsequently differentiates to reform the distal digit.

Takeo and colleagues explored the role of nail epithelial cells in tip regeneration by first localizing nail epithelial stem cells (NSCs). They used a clever trick in mice allowing every progenitor cell of a given keratin-14 (K14+)–expressing basal cell to be labeled and followed in space and time. They discovered that K14+ cells from the proximal nail matrix persisted for over 5 months, giving rise to the proximal and dista…