Simulated microgravity attenuates myogenic differentiation via epigenetic regulations

Area of Science:

• Cell Biology
• Space Biology
• Molecular Biology

Background:

• Myogenic differentiation is crucial for muscle development and is regulated by transcription factors and biomechanical signals.
• Understanding how environmental factors like microgravity affect muscle cells is vital for space exploration and terrestrial applications.

Purpose of the Study:

• To investigate the impact of simulated microgravity on L6 myoblast differentiation and the expression of myogenic regulatory factor (MRF) genes.
• To elucidate the molecular mechanisms underlying microgravity-induced changes in myogenesis, focusing on DNA methylation.

Main Methods:

• Utilized simulated microgravity culture (Gravite®, 10⁻³G) for L6 myoblasts.
• Performed real-time Reverse Transcription Polymerase Chain Reaction (RT-PCR) to analyze gene expression (Myog, Myf6, Mef2c, Des, Ckm, Myod1).
• Employed 5-AzaC treatment and Modified HpaII tiny fragment enrichment by ligation-mediated PCR (HELP)-assay to assess DNA methylation dynamics.

Main Results:

• Simulated microgravity significantly attenuated myogenesis and inhibited the expression of Myod1 and Myog genes.
• Gene expression and myotube differentiation differences between 1G and simulated microgravity conditions were normalized after 5-AzaC treatment.
• Kinetic changes in DNA methylation status were attenuated under simulated microgravity.

Conclusions:

• Microgravity negatively regulates myogenesis and Myod1 expression in L6 myoblasts.
• DNA methylation plays a critical role in mediating the effects of microgravity on muscle differentiation.
• Findings suggest microgravity impacts epigenetic regulation of muscle development.