Cell death-resistance of differentiated myotubes is associated with enhanced anti-apoptotic mechanisms compared to myoblasts
- 16 December 2010
- journal article
- research article
- Published by Springer Science and Business Media LLC in Apoptosis
- Vol. 16 (3), 221-234
- https://doi.org/10.1007/s10495-010-0566-9
Abstract
Skeletal muscle atrophy is associated with elevated apoptosis while muscle differentiation results in apoptosis resistance, indicating that the role of apoptosis in skeletal muscle is multifaceted. The objective of this study was to investigate mechanisms underlying apoptosis susceptibility in proliferating myoblasts compared to differentiated myotubes and we hypothesized that cell death-resistance in differentiated myotubes is mediated by enhanced anti-apoptotic pathways. C2C12 myoblasts and myotubes were treated with H2O2 or staurosporine (Stsp) to induce cell death. H2O2 and Stsp induced DNA fragmentation in more than 50% of myoblasts, but in myotubes less than 10% of nuclei showed apoptotic changes. Mitochondrial membrane potential dissipation was detected with H2O2 and Stsp in myoblasts, while this response was greatly diminished in myotubes. Caspase-3 activity was 10-fold higher in myotubes compared to myoblasts, and Stsp caused a significant caspase-3 induction in both. However, exposure to H2O2 did not lead to caspase-3 activation in myoblasts, and only to a modest induction in myotubes. A similar response was observed for caspase-2, -8 and -9. Abundance of caspase-inhibitors (apoptosis repressor with caspase recruitment domain (ARC), and heat shock protein (HSP) 70 and -25 was significantly higher in myotubes compared to myoblasts, and in addition ARC was suppressed in response to Stsp in myotubes. Moreover, increased expression of HSPs in myoblasts attenuated cell death in response to H2O2 and Stsp. Protein abundance of the pro-apoptotic protein endonuclease G (EndoG) and apoptosis-inducing factor (AIF) was higher in myotubes compared to myoblasts. These results show that resistance to apoptosis in myotubes is increased despite high levels of pro-apoptotic signaling mechanisms, and we suggest that this protective effect is mediated by enhanced anti-caspase mechanisms.Keywords
This publication has 91 references indexed in Scilit:
- Caspase 3/caspase-activated DNase promote cell differentiation by inducing DNA strand breaksProceedings of the National Academy of Sciences, 2010
- Mitochondrial death effectors: Relevance to sarcopenia and disuse muscle atrophyBiochimica et Biophysica Acta (BBA) - General Subjects, 2009
- Skeletal Muscle Differentiation Evokes Endogenous XIAP to Restrict the Apoptotic PathwayPLOS ONE, 2009
- Apoptotic signaling induced by H2O2-mediated oxidative stress in differentiated C2C12 myotubesLife Sciences, 2009
- Identification of cold-shock protein RBM3 as a possible regulator of skeletal muscle size through expression profilingAmerican Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2008
- Global Mapping of the Topography and Magnitude of Proteolytic Events in ApoptosisCell, 2008
- In vivo time-lapse microscopy reveals no loss of murine myonuclei during weeks of muscle atrophyJCI Insight, 2008
- Nuclear Apoptosis Contributes to SarcopeniaExercise and Sport Sciences Reviews, 2008
- Methods for the assessment of mitochondrial membrane permeabilization in apoptosisApoptosis, 2007
- Hsp27 inhibits 6-hydroxydopamine-induced cytochrome c release and apoptosis in PC12 cellsBiochemical and Biophysical Research Communications, 2004