Cell Rep. 2016 May 10;15(6):1277-90. doi: 10.1016/j.celrep.2016.04.022. Epub 2016 Apr 28.

β-Catenin Activation in Muscle Progenitor Cells Regulates Tissue Repair.

Rudolf A¹, Schirwis E², Giordani L², Parisi A¹, Lepper C³, Taketo MM⁴, Le Grand F⁵.

Abstract

Skeletal muscle regeneration relies on a pool of resident muscle stem cells called satellite cells (MuSCs). Following injury-induced destruction of the myofibers, quiescent MuSCs are activated and generate transient amplifying progenitors (myoblasts) that will fuse to form new myofibers. Here, we focus on the canonical Wnt signaling pathway and find that either conditional β-catenin disruption or activation in adult MuSCs results in perturbation of muscle regeneration. Using both in vivo and in vitro approaches, we observed that myoblasts lacking β-catenin show delayed differentiation, whereas myoblasts with constitutively active β-catenin undergo precocious growth arrest and differentiation. Transcriptome analysis further demonstrated that Wnt/β-catenin signaling interacts with multiple pathways and, more specifically, TGF-β signaling. Indeed, exogenous TGF-β2 stimulation restores the regenerative potential of muscles with targeted β-catenin disruption in MuSCs. We conclude that a precise level of β-catenin activity is essential for regulating the amplification and differentiation of MuSC descendants during adult myogenesis.