Skeletal muscles communicate

What is it about?

Exosomes are small vesicles secreted from cells that carry molecules specific to the producing cells, such as proteins, lipids, and nucleic acids. Initially, exosomes were considered responsible for the disposal of unwanted cellular components. However, recent studies revealed that exosomes are part of a communication mechanism through which the producing cell packages molecules and secretes them extracellularly. These will be delivered and taken up by the target recipient cell which will eventually use the exosomal cargo in a specific manner. Exosomes carrying muscle-specific molecules were found upregulated in the blood of muscular dystrophy patients, indicating a possible communication between muscles and other tissues through the delivery of exosomes. In this study, we aimed to investigate the exosomal cargo released by skeletal muscles and their role in muscle tissue crosstalk. We isolated exosomes secreted from muscles located on the legs of healthy mice and we found that they carry small RNA molecules specific for muscle function. Then, we isolated exosomes from the blood of healthy mice and found that a portion encapsulated muscle-specific small RNA molecules. This implies that some exosomes in the blood originated from muscles. Finally, we reduced the levels of muscle-specific RNAs in skeletal muscles and observed that the same molecules were downregulated in neighbouring muscle tissues. This observation indicates local muscle communication through the secretion and delivery of exosomes.

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Why is it important?

Our results show that healthy muscles communicate locally, a finding that will help to elucidate unknown pathways in the development of skeletal muscles.

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