Muscle stem cells, also called satellite cells, colonize a niche that is located between the plasma membrane of the muscle cell and the surrounding basal lamina. Already in newborns these niches contain satellite cells from which both muscle cells and new stem cells can be generated.
Weakened stem cells
In the present study Dr. Bröhl and Professor Birchmeier showed that mouse muscle progenitor cells lacking components of the Notch signaling pathway cannot colonize their niche. Instead the muscle progenitor cells locate in tissue between the muscle fibers. The developmental biologists view this as the cause for the weakening of the muscles. The stem cells that are “in the wrong place” are no longer as potent as they originally were and hardly contribute to muscle growth.
In addition, the Notch signaling pathway has a second function in muscle development. It prevents the differentiation of stem cells into muscle cells through suppression of the muscle developmental factor MyoD and thus ensures that there will always be a pool of stem cells for muscle repair and regeneration. In the future this work could gain in importance for research on muscle regeneration and muscle weakness.
*Colonization of the Satellite Cell Niche by Skeletal Muscle Progenitor Cells Depends on Notch Signals
Dominique Bröhl1, Elena Vasyutina1,#, Maciej T. Czajkowski1, Joscha Griger1, Claudia Rassek1, Hans-Peter Rahn2, Bettina Purfürst3, Hagen Wende1 and Carmen Birchmeier1*
1Developmental Biology/Signal Transduction Group, 2Preparative Flow Cytometry and 3Electron Microscopy Core Facility
Max-Delbrück-Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125 Berlin, Germany
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