Community effect triggers terminal differentiation of myogenic cells derived from muscle satellite cells by quenching Smad signaling.
A high concentration of bone morphogenetic proteins (BMPs) stimulates myogenic progenitor cells to undergo heterotopic osteogenic differentiation. However, the physiological role of the Smad signaling pathway during terminal muscle differentiation has not been resolved. We report here that Smad1/5/8 was phosphorylated and activated in undifferentiated growing mouse myogenic progenitor Ric10 cells without exposure to any exogenous BMPs. The amount of phosphorylated Smad1/5/8 was severely reduced during precocious myogenic differentiation under the high cell density culture condition even in growth medium supplemented with a high concentration of serum. Inhibition of the Smad signaling pathway by dorsomorphin, an inhibitor of Smad activation, or noggin, a specific antagonist of BMP, induced precocious terminal differentiation of myogenic progenitor cells in a cell density-dependent fashion even in growth medium. In addition, Smad1/5/8 was transiently activated in proliferating myogenic progenitor cells during muscle regeneration in rats. The present results indicate that the Smad signaling pathway is involved in a critical switch between growth and differentiation of myogenic progenitor cells both in vitro and in vivo. Furthermore, precocious cell density-dependent myogenic differentiation suggests that a community effect triggers the terminal muscle differentiation of myogenic cells by quenching the Smad signaling.
Department of Regenerative Medicine, National Institute for Longevity Sciences, National Center for Geriatrics and Gerontology, 35 Gengo, Morioka, Oobu, Aichi 474-8522, Japan.
Michiko
M
Yanagisawa
Atsushi
A
Mukai
Kosuke
K
Shiomi
Si-Yong
SY
Song
Naohiro
N
Hashimoto
D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D005260:Female; D051379:Mice; D008813:Mice, Inbred ICR; D032342:Muscle Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D032446:Myoblasts / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D032496:Satellite Cells, Skeletal Muscle / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D051785:Smad Proteins / Q000378:metabolism*; D051898:Smad1 Protein / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology
D019485:Bone Morphogenetic Proteins; D051785:Smad Proteins; D051898:Smad1 Protein