Nail stem cells prove more versatile than press-ons

Scientists make a surprising discovery that could help in the repair of skin injuries and amputations

There are plenty of body parts that don’t grow back when you lose them. Nails are an exception, and a new study by a team ofUSC Stem Cell researchers could help unlock their secrets — and even make it potentially possible to regrow other body tissue.

The team, led by principal investigator Krzysztof Kobielak and co-first authors Yvonne Leung and Eve Kandyba, has identified a new population of nail stem cells with the ability to either self-renew or undergo specialization or differentiation into multiple tissues.

In essence, scientists could potentially manipulate cells from a human’s regrowable body parts to perhaps grow other tissue types.

To find these elusive stem cells, the team used a sophisticated system to attach fluorescent proteins and other visible “labels” to mouse nail cells.

The researchers discovered that these slow-dividing stem cells have the flexibility to perform dual roles. Under normal circumstances, the stem cells contribute to the growth of both the nails and the adjacent skin. However, if the nail is injured or lost, a protein called “Bone Morphogenetic Protein,” signals to the stem cells to shift their function exclusively to nail repair.

The researchers are now wondering whether the right signals or environmental cues could induce these nail stem cells to generate additional types of tissue — potentially aiding in the repair of everything from nail and finger defects to severe skin injuries and amputations.

“That was a very surprising discovery, since the dual characteristic of these nail stem cells to regenerate both the nail and skin under certain physiological conditions is quite unique and different from other skin stem cells, such as those of the hair follicle or sweat gland,” Kobielak said.

The team’s study was published in The Proceedings of the National Academy of Sciences. Additional co-authors included USC researchers Yi-Bu Chen, Seth Ruffins and Cheng-Ming Chuong.