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Imbalance between pSmad3 and Notch induces CDK inhibitors in old muscle stem cells

A Corrigendum to this article was published on 27 July 2016

This article has been updated


Adult skeletal muscle robustly regenerates throughout an organism’s life, but as the muscle ages, its ability to repair diminishes and eventually fails1,2. Previous work suggests that the regenerative potential of muscle stem cells (satellite cells) is not triggered in the old muscle because of a decline in Notch activation, and that it can be rejuvenated by forced local activation of Notch3. Here we report that, in addition to the loss of Notch activation, old muscle produces excessive transforming growth factor (TGF)-β (but not myostatin), which induces unusually high levels of TGF-β pSmad3 in resident satellite cells and interferes with their regenerative capacity. Importantly, endogenous Notch and pSmad3 antagonize each other in the control of satellite-cell proliferation, such that activation of Notch blocks the TGF-β-dependent upregulation of the cyclin-dependent kinase (CDK) inhibitors p15, p16, p21 and p27, whereas inhibition of Notch induces them. Furthermore, in muscle stem cells, Notch activity determines the binding of pSmad3 to the promoters of these negative regulators of cell-cycle progression. Attenuation of TGF-β/pSmad3 in old, injured muscle restores regeneration to satellite cells in vivo. Thus a balance between endogenous pSmad3 and active Notch controls the regenerative competence of muscle stem cells, and deregulation of this balance in the old muscle microniche interferes with regeneration.

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Figure 1: TGF-β/pSmad3, but not myostatin, increases in old skeletal muscle.
Figure 2: Notch removes pSmad3 from the 5′ regulatory regions of CDK inhibitors.
Figure 3: Inhibition of endogenous Notch upregulates CDK inhibitors.
Figure 4: Smad3 shRNA rescues responses of satellite cells in old niche in vivo.

Change history

  • 27 July 2016

    Nature 454, 528–532 (2008); doi:10.1038/nature07034 In Fig. 1a of this Letter, the immunofluorescence images for myostatin and follistatin are inaccurate owing to many versions of this figure in multiple revisions of our manuscript. Specifically, the immunofluorescence panels representing anti-myostatin and anti-follistatin staining were duplicated.


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We thank R. Derynck and M. Conboy for discussions. This work was supported by National Institutes of Health (NIH) R01 (AG027252), NIH R21 (AG27892) and Ellison’s Medical Foundation grants to I.M.C., and a Pre-doctoral Training Fellowship from the California Institute for Regenerative Medicine training grant to M.E.C.

Author Contributions M.E.C. performed all experiments, analysed the data and contributed to the writing of the manuscript; M.H. performed preliminary experiments for Fig. 1a, b, d and Supplementary Figs 4 and 11; and I.M.C. designed the study, participated in experiments, interpreted the data and wrote the manuscript.

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Correspondence to Irina M. Conboy.

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Carlson, M., Hsu, M. & Conboy, I. Imbalance between pSmad3 and Notch induces CDK inhibitors in old muscle stem cells. Nature 454, 528–532 (2008).

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