Epidermal growth factor receptor down-regulation triggers human myoblast differentiation

PLoS One. 2013 Aug 15;8(8):e71770. doi: 10.1371/journal.pone.0071770. eCollection 2013.

Abstract

Initiation of human myoblast differentiation requires a negative shift (hyperpolarization) of the resting potential of myoblasts that depends on the activation of Kir2.1 potassium channels. These channels are regulated by a tyrosine phosphorylation. Using human primary myoblast culture, we investigated a possible role of various receptor tyrosine kinases in the induction of the differentiation process. We found that Epidermal Growth Factor Receptor (EGFR) is a key regulator of myoblast differentiation. EGFR activity is down-regulated during early human myoblast differentiation, and this event is required for normal differentiation to take place. Furthermore, EGFR silencing in proliferation conditions was able to trigger the differentiation program. This occurs through an increase of Kir2.1 channel activity that, via a rise of store-operated Ca(2+) entry, leads to the expression of myogenic transcription factors and muscle specific proteins (Myogenin, Myocyte Enhancer Factor 2 (MEF2), Myosin Heavy Chain (MyHC)). Finally, blocking myoblast cell cycle in proliferation conditions using a cdk4 inhibitor greatly decreased myoblast proliferation but was not able, on its own, to promote myoblast differentiation. Taken together, these results show that EGFR down-regulation is an early event that is required for the induction of myoblast differentiation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Checkpoints
  • Cell Differentiation / genetics*
  • Cells, Cultured
  • ErbB Receptors / genetics*
  • ErbB Receptors / metabolism
  • Gene Expression Regulation
  • Gene Silencing
  • Humans
  • Myoblasts / cytology*
  • Myoblasts / metabolism*
  • Potassium Channels, Inwardly Rectifying / genetics
  • Potassium Channels, Inwardly Rectifying / metabolism
  • Transcriptional Activation

Substances

  • Kir2.1 channel
  • Potassium Channels, Inwardly Rectifying
  • ErbB Receptors

Grants and funding

This work was supported by grants from the Fonds National Suisse de la Recherche Scientifique (310030-124910 and 310030-141113), Fondation Suisse de Recherche sur les Maladies Musculaires, Fondation Hans Wilsdorf, and Fondation Marcel Levaillant. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.