Fig. 4.

Activation of Wnt signaling during muscle regeneration. (A) In quiescent satellite cells, Wnt signaling (blue line) is inactive; (B, C) Canonical Wnt signaling suppresses the Notch pathway, leading the satellite cell to switch from proliferation to differentiation. (D) Wnt signaling induces myogenic gene expression via Barx2 activation, stimulates Follistatin, inhibits myostatin, and translocates the negative regulator Setdb1 into the cytoplasm, promoting myoblast development and fusion. (E) Finally, Wnt activity returns to low levels. Overall, Wnt/β-catenin signaling must be regulated in a timely manner for muscle regeneration to occur.³⁰,³⁵,³⁷-³⁹)