NEWS
PROTEIN HELPS
SPEED WOUND HEALING
Pre-treatment with a stem-cell-activating protein significantly enhances healing said Stanford researchers. The approach could
eventually help people going into surgery heal better from injuries they sustain.
Stem cells respond more quickly
to injury when they’ve been
previously primed with one dose
of a single protein, according to a
study from the Stanford University
School of Medicine.
Mice given the priming protein
recover muscle function more quickly
after damage, their skin heals more
rapidly and even the shaved area around
the injury regrows hair more quickly,
the study found. Harnessing the power
of this protein may one day help people
recover more quickly from surgery
or restore youthful vigour to aging
stem cells.
“We’re trying to better understand
wound healing in response to trauma
and ageing,” said Prof Thomas
Rando, Professor of Neurology and
Neurological Sciences. “We’ve shown
that muscle and bone marrow stem
cells enter a stage of alertness in
response to distant injury that allows
them to spring into action more quickly.
Now we’ve pinpointed the protein
responsible for priming them to do what
they do better and faster.”
POTENTIAL THERAPY
“Our research shows that by priming
the body before an injury you can
speed the process of tissue repair
and recovery, similar to how a vaccine
prepares the body to a fight infection,”
said lead author and Assistant
Professor of Stem Cell Biology and
regenerative medicine at the University
of Southern California Prof Joseph
Rodgers. “We believe this could be
a therapeutic approach to improve
recovery in situations where injuries can
be anticipated, such as surgery, combat
or sports.”
Normally, adult, tissue-specific
stem cells are held in a kind of cellular
deep freeze called quiescence to avoid
12 MAY 2017 | MEDICAL CHRONICLE
Rodgers and his colleagues found that a protein can activate a critical signalling pathway in the cells by binding to their surfaces
unnecessary cell division in the absence
of injury. In a 2014 paper published in
Nature, Rodgers and Rando showed in
laboratory mice that an injury to the
muscle of one leg caused a change
in the muscle stem cells of the other
leg. These cells entered what the
researchers called an 'alert' phase of
the cell cycle that is distinct from either
fully resting or fully active stem cells.
The fact that muscle stem cells
distant from the injury were alerted
indicated that the damaged muscle
must release a soluble factor that can
travel throughout the body to wake up
quiescent stem cells. Rodgers and his
colleagues found that a protein called
hepatocyte growth factor (HGF), which
exists in a latent form in the spaces
between muscle cells and tissue, can
activate a critical signalling pathway in
the cells by binding to their surfaces.
This pathway stimulates the production
of proteins important in alerting the
stem cells. But it wasn’t known how
HGF itself became activated.
In the new study, Rodgers and his
colleagues identified the activating
factor by injecting uninjured animals
with blood serum isolated from animals
with an induced muscle injury. After
2.5 days, the researchers found that
muscle stem cells from the recipient
animals were in an alert state and
completed their first cell division much
more quickly than occurred in animals
that had received blood serum from
uninjured mice. “Clearly, blood from the
injured animal contains a factor that
alerts the stem cells,” said Prof Rando.
“We wanted to know, what is it in the
blood that is doing this?”
INCREASED LEVELS OF
A PROTEIN
The serum from the injured
animals had the same levels of
HGF as the control serum. However,
it did have increased levels of a
protein called HGFA that activates
HGF by snipping it into two pieces.
Treating the serum with an antibody
that blocked the activity of HGFA
eliminated the recovery benefit
of pre-treatment.
In a related experiment, exposing
the animals to a single intravenous
dose of HGFA alone two days prior
to injury helped the mice recover
more quickly. “Just like in the muscles,
we saw the responses in the skin
were dramatically improved when
the stem cells were alerted,” Prof
Rando said.