Gravitational force modulates G2/M phase exit in mechanically unloaded myoblasts
Tatiana Benavides Damm1, Alfredo Franco-Obregón, Marcel Egli
1CC Aerospace Biomedical Science & Technology; Space Biology Group; University of Applied Sciences and Arts; Hergiswil, Switzerland; Institute for Biomechanics; Eidgenössische Technische Hochschule Zürich; Zürich, Switzerland.
Cell Cycle (Georgetown, Tex.)
|August 27, 2013
Summary
Spaceflight causes muscle atrophy by slowing cell growth. Simulated microgravity delayed cell cycle progression, but hypergravity did not, suggesting distinct cellular responses to mechanical unloading and loading.
Area of Science:
- Cell Biology
- Space Medicine
- Skeletal Muscle Physiology
Background:
- Prolonged spaceflight leads to muscle mass loss and reduced strength, known as space atrophy.
- Microgravity causes mechanical unloading of skeletal muscle myoblasts, impairing cell proliferation and altering protein expression.
Purpose of the Study:
- To investigate the mechanisms behind muscle mass decline during microgravity exposure.
- To analyze the effects of simulated microgravity on C2C12 mouse muscle cell proliferation, cell cycle, and cyclin expression.
Main Methods:
- Culturing C2C12 mouse muscle cells under simulated microgravity (SM) and hypergravity (HG).
- Analyzing cell proliferation, cell cycle progression, and expression of cyclin B and D.
Main Results:
- Simulated microgravity (SM) significantly retarded cell growth and delayed G2/M phase progression by approximately 16 hours.
- Cells accumulated between the G2 checkpoint and anaphase onset in SM, with positive cyclin B expression.
- Hypergravity (HG) conditions did not affect proliferation or cell cycle progression, similar to 1g controls.
Conclusions:
- Simulated microgravity and hypergravity induce distinct cellular responses in cell cycle progression.
- The negative effects of microgravity on cell cycle progression can be reversed by normal terrestrial gravity.
- Cellular mechanotransduction pathways respond differently to mechanical unloading versus loading.
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