Are Fingernails a Key to Unlocking the Puzzle of Mammalian Limb Regeneration?

The document from 2017 examines the significance of the nail bed and its stem cells in the regeneration of mammalian digit tips. It highlights the necessity of Wnt signaling and Lgr6 for successful regeneration and suggests that nail stem cells and their niche play a key role, but are not the only factors involved. The study found that Msx1-expressing fibroblasts in the nail bed are essential for regeneration, but these cells are not multipotent and only regenerate the nail bed itself. Genetic lineage analyses revealed that the blastema is a heterogeneous mix of cells from different tissues, not a group of multipotent progenitors. The niche for nail stem cells is not well-defined, but Wnt signaling and Lgr proteins may be important in the nail stem cell-niche relationship. The unique anatomy around the nail organ might allow Wnt signals to influence nearby cell types, aiding in regeneration. Understanding these mechanisms could be crucial for stimulating regeneration in non-regenerative tissues such as arms or legs.