Scientists Discover Possible Way to Regrow Soft Tissues: Capturing the Ability to Heal

Repairing tissues is almost effortless in young animals, and children often heal more easily than adults. Learning how to capture this healing ability in the elderly, though, has long been a focus of research. Now, scientists have discovered that by reactivating a dormant gene called Lin28a, which is active in embryonic stem cells, they were able to regrow hair and repair cartilage, bone, skin and other soft tissues in a mouse model. The findings bode well for future research into the science of healing.

"Efforts to improve wound healing and tissue repair have mostly failed, but altering metabolism provides a new strategy which we hope will prove successful," said George Daley, the senior investigator of the new study, in a news release.

Lin28 was first discovered in worms, but functions in all complex organisms. It's abundant in embryonic stem cells and is strongly expressed during early embryo formation. In fact, it's been used to reprogram skin cells into stem cells. It acts by binding to RNA and regulating how genes are translated into proteins.

In order to better understand how Lin28a promotes tissue repair, the researchers systematically looked at what specific RNAs it binds to. In the end, they found that Lin28a enhances the production of metabolic enzymes in mitochondria, the structures that produce energy for the cell. By revving up a cell's bioenergetics, Lin28a helps generate the energy needed to grow new tissues.

"We already know that accumulated defects in mitochondrial metabolism can lead to aging in many cells and tissues," said Shyh-Chang Ng, one of the researchers, in a news release. "We are showing the converse-that enhancement of mitochondrial metabolism can boost tissue repair and regeneration, recapturing the remarkable repair capacity of juvenile animals."

In fact, the scientists found with other experiments that by bypassing Lin28a and directly activating mitochondrial metabolism with a small-molecule compound, it was possible to enhance wound healing. These findings suggest the possibility of inducing regeneration and promoting tissue repair with drugs.

"Since Lin28 itself is difficult to introduce into cells, the fact that we were able to activate mitochondrial metabolism pharmacologically gives us hope," said Shyh-Chang in a news release. "Lin28a could be a key factor in constituting a healing cocktail."

The findings are published in the journal Cell.