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Source: ONE News
A new understanding of the genes that make muscle cells may
change the way researchers think about stem cell transplants for
muscular dystrophy and muscle injuries, US researchers said.
In a surprise finding, they said genes important for forming muscle
cells in embryos and newborns are not normally active in adult stem
cells.
And researchers hoping to use muscle stem cells in stem-cell
transplant therapies should not assume genes that control early
muscle development serve the same purpose in repairing adult
muscle, Christoph Lepper and colleagues at the Carnegie Institution
in Baltimore reported in the journal Nature.
Earlier studies have shown that two genes - Pax3 and Pax7 - control
cells that give rise muscle in embryos, and Pax7 also helps build
muscle in newborn mice.
To get a better understanding of their function, Lepper and
colleagues studied these genes at various stages of development in
live mice.
"I thought that if they are so important in the embryo, they must
be important for adult muscle stem cells," Lepper said in a
statement.
The team used genetic engineering to suppress both the Pax3 and
Pax7 genes in adult muscle stem cells, and they found that adult
stem cells were still able to function normally.
"I was totally surprised to find that the muscle stem cells are
normal without them," Lepper said.
The researchers then looked at whether the same was true in injured
muscles, when muscle stem cells go to work making new muscle
tissue.
To study this, they injured mouse leg muscles between the knee and
ankle, and found the muscle stem cells were able to make new
muscle, even without the two key embryonic muscle stem cell
genes.
The team said the embryonic muscle cell genes appear to only be
active in mice within the first three weeks after birth.
After that, they believe the genes go quiet and allow a
different set of genes to take over.
Finding those genes will be important as scientists pursue new
treatments for diseases like muscular dystrophy, a genetic,
degenerative disease that affects voluntary muscles, they
said.
And they said teams should look at other types of stem cells to see
how age might affect their properties, and they should take age of
stem cells into account in transplant-based treatments.
