Fountain-of-youth gene unleashes healing power

Mice that had been genetically engineered to develop tumours failed to do so. Instead, the
animals grew up to be huge and very hairy. And
when the tips of the pups’ toes were clipped off in
a routine tagging procedure, they often grew back.

What was different about these mice was that they carried
a protein, Lin28a,which is generally
produced only in developing embryos.
Lin28a has already
garnered attention
for its involvement in
the functioning of
stem cells and in
cancer.

A study
published today in
Cell 1 now shows
that this protein can
improve tissue repair
— even in adults. In mice genetically modified to
produce the protein throughout their lives, the
animals’ hair grew faster than normal and puncture wounds in their ears healed almost completely.

“We were just so shocked that such a small change
in this gene could have profound effects on a
complex regenerating tissue,” says Hao Zhu, a cell
biologist at the University of Texas Southwestern
Medical Center in Dallas and an author on the
study.

Resetting cells using embryonic genes has been
seen before, most prominently in the creation of
cells known as induced pluripotent stem cells,
which acquire an embryonic-like state after a suite
of genes is activated.

But the latest study reveals
that such de-ageing changes can be made not just in cultured cells, but in developed tissues within an
organism. It suggests that it might be possible to
make older tissues behave more like young ones,
which are much better at repairing damage.

In mammalian fetuses, for example, even deep
wounds can heal without scarring.
“Your body knows what age it is, and genes regulate that knowledge,” says Zhu.
“There are genetic regulators that
dictate that. We don't know
what all of them are, but I think Lin28a is one of
them.”