Molecular Switch Holds Key To Reserve Supply Of Muscle Stem Cells

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Fountain Of Youth: Molecular Switch Holds Key To Reserve Supply Of

Muscle Stem Cells

http://www.medicalnewstoday.com/medicalnews.php?newsid=64960

After injury, even adult muscles can heal very well because they

have a reserve supply of muscle stem cells, called satellite cells,

which they can utilize for repair. Until now, it was unclear how

this supply of satellite and muscle progenitor cells, out of which

both muscle cells as well as satellite cells develop, keeps

itself " fresh " . Developmental biologists Professor Carmen

Birchmeier, Dr. Elena Vasyutina, and Lenhard of the Max

Delbrück Center for Molecular Medicine (MDC) Berlin-Buch, Germany,

have now demonstrated that a molecular switch, abbreviated RBP-J,

regulates this " fountain of youth " . If the switch is absent, the

satellite cells generate muscle cells in an uncontrolled way,

resulting in the depletion of the satellite cell reserves. As a

consequence, too few muscles form during the developmental phase of

a living organism and the fetus can no longer build up a reserve

supply of satellite cells. The MDC scientists' research report,

which could be of significance for the future development of stem

cell therapies, has just been published in the online edition of the

Proceedings of the National Academy of Sciences (PNAS).

Muscle stem cells were discovered in the beginning of the 1960s. For

a long time, researchers could only identify them with the aid of an

electron microscope. These cells are located between the muscle cell

membrane and the layer surrounding it (the basal membrane). It has

been known for some time that satellite cells have characteristic

surface molecules and transcription factors which allow researchers

to find these cells more easily.

The RBP-J switch is involved in a signaling pathway which is

critical for cell communication, the Notch signaling pathway, and is

known to be a key mediator of signaling information. The signaling

pathway plays a major role both in the development of a living

organism and in the adult organism.

The researchers' evidence that satellite cells and muscle progenitor

cells preserve their stem cell character because RBP-J makes them

persist in an earlier developmental stage takes on special

significance against the background of previous stem cell therapy

experiments. Other research groups have previously shown that

muscles regenerate very well when satellite cells are directly

injected into the muscles of mice. Moreover, due to this, the

muscles also replenish their reserves of satellite cells.

Influencing RBP-J could improve therapies that are based on

satellite cells.

About the MAX DELBRUECK CENTRE FOR MOLECULAR MEDICINE (MDC)

The Max Delbrueck Centre for Molecular Medicine (MDC) Berlin-Buch

combines microbiological basic research with clinical research in

order to develop new diagnosis and treatment methods for serious

diseases.

MAX DELBRUECK CENTRE FOR MOLECULAR MEDICINE (MDC)

-Roessle-Str. 10

Berlin - Buch

http://www.mdc-berlin.de