Myoblast Exosome Production, Function, and MiRNA Cargo Is Altered by Mechanical Stimulation: Therapeutic Implications for Skeletal Muscle Regeneration

Introduction: Exosomes offer a potential cell-free regenerative therapy which may replicate the benefits of MSC therapy while minimizing their risks and regulatory challenges. Our previous work demonstrated that mechanical strain improves the myogenic functions of exosomes derived from myoblasts. The goal of the current study was to investigate changes in exosomal miRNA cargo following mechanical stimulation of myoblasts and identify candidate miRNAs that modulate myogenesis. We hypothesized that exosomes derived from mechanically strained myoblasts would have differential expression of miRNAs known to play a role in myogenesis.

Materials and Methods: C2C12 myoblasts were cultured under cyclical tension using a FlexCell FX-5000TT bioreactor alongside unstrained, static controls. Exosomes were then isolated from conditioned media. RNA was extracted from the exosomes and RNA sequencing and gene ontology enrichment analysis was performed to identify differentially expressed miRNAs and their associated molecular functions.

Results: 35 miRNAs were significantly downregulated in strained exosomes compared with static. The GO terms associated with the mRNA targets of downregulated miRNAs involved developmental, neural, cell signalling, transcriptional regulation, metabolic, and inflammatory processes.

Discussion/Conclusion: This study demonstrates that mechanical stimulation alters the miRNA cargo of myoblast exosomes. These miRNAs may have biological functions impacting muscle adaptation to mechanical strain including developmental, neural, metabolic, and inflammatory processes. Mechanically strained myoblast exosomes hold potential as an alternative therapeutic to mimic the benefits of physical exercise on muscle by improving muscle regeneration and function in individuals with impaired muscle regeneration.

Acknowledgements: This project was funded by the Laboratory of Comparative Musculoskeletal Oncology and Traumatology, the Limb Preservation Foundation, and the Steadman Philippon Research Institute.

Publication History

Article published online:
26 October 2022