Deer stem cells used to grow 'mini antlers' on mice

Deer stem cells have been used to grow antler-like structures on the foreheads of mice, opening the possibility that these cells could be used for limb regeneration in the future.

Deer antlers fall off and regenerate each year, meaning deer are one of the few mammals that have not completely lost the ability to regenerate body appendages. However, the cellular processes involved are not fully understood.

'... to address this fundamental question, we set out to investigate in detail the cellular composition and gene expression dynamics of antler tissue throughout its regeneration cycle.' said lead author of the paper published in Science, Tao Qin, and his colleagues.

Led by Professor Qiu Qiang, and his PhD student, Qin, researchers based at the Northwestern Polytechnical University in Xi'an, China, began by studying around 75,000 cells from deer antlers before, during and after the antlers fell off. Using a technique called RNA sequencing, the team identified a specific group of stem cells that were essential for antler regeneration.

The research team found that ten days before the antlers were shed, there was a significant increase in one type of stem cell in the stump that is left when the antlers fall off. A further five days later, these stem cells had generated a new subtype of stem cell, which the researchers named antler blastema progenitor cells (ABPCs).

Ten days after the antlers fell off, the researchers found that the ABPCs had begun to form bone and cartilage cells. Certain genes expressed in the ABPCs were also expressed in cells that help to regenerate tissue in other species, such as mice, which can regenerate the tips of digits. This may suggest these genes are important across species for the regeneration of limbs.

The researchers next wanted to find out if ABPCs could be used to grow antler-like structures in mice. Hence, ABPCs were extracted from deer, grown in the laboratory and then transplanted into the foreheads of mice. Just 45 days later, the mice had grown bumps on their head that resembled antler-like structures. Significantly, these mini antlers contained bone and cartilage.

The recent study, builds on previous research also carried out in China that grew antler stumps on mice skulls by inserting deer antler tissue beneath the forehead skin.

The results from Qin's research may have implications for research into human limb regeneration. The authors explained, 'the induction of human cells into ABPC-like cells could be used in regenerative medicine for skeletal injuries or limb regeneration.' However, further work is needed before the importance of the recent findings can be understood.