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Inhibition of mitochondrial protein synthesis impaired C2C12 myoblast differentiation
1Division of Physiology, Osaka University, Japan.
Abstract:
Various factors are required for the regulation of muscle cell differentiation. In an attempt to elucidate the mechanism underlying myogenesis, we examined the possible contribution of mitochondria to terminal differentiation of murine myoblast cell line, C2C12, using a specific inhibitor for mitochondrial protein synthesis, tetracycline. Tetracycline impaired myotube formation and induction of muscle creatine kinase activity which was specifically observed in differentiated myocytes. Transcript levels of muscle-specific proteins, creatine kinase and troponin-I were also significantly suppressed in a dose-dependent manner. However, those proteins with myogenic regulatory factors, MyoD and myogenin, and common proteins including glycolytic enzymes were not affected. Cellular viability, mitochondrial transcription, and mitochondrial proliferation were confirmed not to be impaired by tetracycline treatment. These results suggest that mitochondrial stress may affect regulation of differentiation-specific gene expression. This system may contribute to an understanding of mechanisms for differentiation inhibition caused by inhibitors of mitochondrial protein synthesis that have also been observed in other kinds of cells.
Insights
Mitochondrial stress inhibits muscle cell differentiation by suppressing specific gene expression, without affecting cell viability or key regulatory factors. This finding offers insights into differentiation inhibition mechanisms.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Muscle cell differentiation (myogenesis) is a complex process regulated by various factors.
- Mitochondria play crucial roles in cellular energy metabolism and homeostasis.
- The specific contribution of mitochondrial function to myogenesis remains incompletely understood.
Purpose of the Study:
- To investigate the role of mitochondrial protein synthesis in the terminal differentiation of C2C12 myoblasts.
- To elucidate the impact of inhibiting mitochondrial protein synthesis on myogenesis and muscle-specific gene expression.
Main Methods:
- Utilized tetracycline, a specific inhibitor of mitochondrial protein synthesis, on C2C12 murine myoblast cell line.
- Assessed myotube formation and muscle creatine kinase activity.
- Quantified transcript levels of muscle-specific proteins (creatine kinase, troponin-I) and myogenic regulatory factors (MyoD, myogenin).
- Evaluated cellular viability, mitochondrial transcription, and mitochondrial proliferation.
Main Results:
- Tetracycline treatment dose-dependently impaired myotube formation and muscle creatine kinase activity.
- Suppression of creatine kinase and troponin-I transcript levels was observed.
- Myogenic regulatory factors (MyoD, myogenin) and glycolytic enzyme expression remained unaffected.
- Cellular viability, mitochondrial transcription, and proliferation were not compromised by tetracycline.
Conclusions:
- Mitochondrial stress, induced by inhibiting mitochondrial protein synthesis, negatively impacts differentiation-specific gene expression during myogenesis.
- These findings suggest that mitochondrial integrity and function are critical for the precise regulation of muscle cell differentiation.
- The study provides a framework for understanding how mitochondrial dysfunction can lead to differentiation inhibition in various cell types.