[PDF][PDF] Calcitonin receptor signaling inhibits muscle stem cells from escaping the quiescent state and the niche

M Yamaguchi, Y Watanabe, T Ohtani, A Uezumi… - Cell reports, 2015 - cell.com
M Yamaguchi, Y Watanabe, T Ohtani, A Uezumi, N Mikami, M Nakamura, T Sato, M Ikawa
Cell reports, 2015cell.com
Calcitonin receptor (Calcr) is expressed in adult muscle stem cells (muscle satellite cells
[MuSCs]). To elucidate the role of Calcr, we conditionally depleted Calcr from adult MuSCs
and found that impaired regeneration after muscle injury correlated with the decreased
number of MuSCs in Calcr-conditional knockout (cKO) mice. Calcr signaling maintained
MuSC dormancy via the cAMP-PKA pathway but had no impact on myogenic differentiation
of MuSCs in an undifferentiated state. The abnormal quiescent state in Calcr-cKO mice …
Summary
Calcitonin receptor (Calcr) is expressed in adult muscle stem cells (muscle satellite cells [MuSCs]). To elucidate the role of Calcr, we conditionally depleted Calcr from adult MuSCs and found that impaired regeneration after muscle injury correlated with the decreased number of MuSCs in Calcr-conditional knockout (cKO) mice. Calcr signaling maintained MuSC dormancy via the cAMP-PKA pathway but had no impact on myogenic differentiation of MuSCs in an undifferentiated state. The abnormal quiescent state in Calcr-cKO mice resulted in a reduction of the MuSC pool by apoptosis. Furthermore, MuSCs were found outside their niche in Calcr-cKO mice, demonstrating cell relocation. This emergence from the sublaminar niche was prevented by the Calcr-cAMP-PKA and Calcr-cAMP-Epac pathways downstream of Calcr. Altogether, the findings demonstrated that Calcr exerts its effect specifically by keeping MuSCs in a quiescent state and in their location, maintaining the MuSC pool.
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