A new paper published in Nature describes the role of nail stem cells in coordinating both nail growth and regrowth of digit-tips after amputation in mice. Researchers in the lab of Dr. Mayumi Ito, PhD, at New York University's Langone Medical Center, first used lineage tracing to identify the nail stem cells responsible for nail growth. They then determined that Wnt signaling is necessary for differentiation of the stem cells into the cells of the nail. Subsequent analysis of amputated digits showed that nail stem cells, and Wnt signaling, were also required for regeneration of the digit. Wnt signaling appears to induce nerve regrowth, which is known to be critical for regeneration in amphibians. While digits were able to regenerate so long as nail stem cells and the underlying epithelium were present, amputations that removed this epithelium failed to regenerate. The epithelium is a source of Wntless, the molecule that initiates Wnt signaling. Studies such as this, which describe the signals controlling cell growth and differentiation, may lead to potential therapies for amputees. The first author on the paper, postdoctoral fellow Makoto Takeo, PhD, was supported by a NYSTEM Institutional Training award (C026880).
Takeo M, Chou WC, Sun Q, Lee W, Rabbani P, Loomis C, Taketo MM, Ito M. Wnt activation in nail epithelium couples nail growth to digit regeneration. Nature. 2013 Jun 12. [Epub ahead of print]