Slide

Unravelling SAC Dependent Behaviour In C2C12
Myoblasts During Myogenesis With Stretching
Conditions
Elsa Thomasson, Janos Vörös, Alfredo Franco-Obregón Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich Introduction
Today there is a big interest in muscle related disorders such as sarcopenia myoblasts under cyclic stretch maintains them proliferative whereas ramp and muscular dystrophy. In order to combat these diseases new therapies stretch biases their development towards differentiation. It has been and technologies to enhance muscle regeneration have to be developed suggested that calcium dependent signaling pathways may regulate cell based on a better understanding of muscle development, myogenesis. fusion but the mechanisms controlling the transmembrane calcium fluxes Activated myoblasts first undergo many rounds of cell division. Depending that render myoplasmic calcium homeostasis remain unclear. The aim of on the biochemical and mechanical environment, myoblasts may next this work is to investigate whether mechanically regulated calcium influx is withdraw from the cell cycle in preparation for biochemical differentiation, an upstream initiator of the biochemical signaling pathway leading to culminating with fusion to form multinucleated myotubes. Placing myogenic or non-myogenic gene expression.
Materials and Methods
C2C12 myoblasts were put under 2D uniaxial cyclic stretch (STREX-ST-140-10 from B-Bridge International) in presence of streptomycin, a stretch activated calcium channel (SAC) blocker or nifedipine, a voltage gated L-type calcium channel blocker. The stretching times were varied and the expression of the two isoforms of Insulin-like Growth Factor 1 (IGF-1) namely IGF-1Ea and Mechano Growth Factor (MGF) were analyzed with real-time PCR. IGF-1Ea and MGF have earlier been shown to have oppsite effects where MGF maintains the cells proliferative while IGF-1Ea pushes them towardsthe differentation pathway.
Control - MGF
Control - MGF
Nifed - MGF
Strept - MGF
ontro 400
stati 300
tatio 100
antitatio
Stretching time (Minutes)
Stretching time (Minutes)
Control - IGF-1Ea
Control - IGF-1Ea
Nifed - IGF-1Ea
Strept - IGF-1Ea
static co
ative 200
tion rela
uantitati
Stretching time (Minutes)
Stretching time (Minutes)
Conclusions and Discussion
Acknowledgements
• Stretch increases the MGF expression and hence the proliferative state is favoured.
• Stretch increases IGF-1Ea expression but not to the same extent as MGF indicating that cyclic stretch ETH Zurich is acknowledged for funding.
• The stretch effect is rescued in samples treated with streptomycin showing that stretch induced upregulation of MGF is mediated via calcium influx through stretch activated calcium channels (SACs).
• Nifedipine has a similar rescuing effect which strengthens the conclusion that the stretch effect is calcium dependent.

Source: http://www.lbb.ethz.ch/Publications/Posters/Poster_Termis_WC_and_ESB_Elsa.pdf