A new study published in the journal Science reveals a unique cellular form of communication that controls muscle repair. In damaged muscle, stem cells must work with immune cells to complete the repair process, but how these cells coordinate to ensure efficient removal of dead tissue before making new muscle fibers remains unknown. Scientists have now shown that a natural substance called hyaluronic acid, used in cosmetics and injections for osteoarthritis, is a key molecule in managing this fundamental interaction.
“When muscles are damaged, it is important that immune cells enter the tissue quickly and clear the damaged cells before they dry out Start repairing,” said Dr. Jeffrey Dilworth, senior scientist at Ottawa Hospital, professor at the University of Ottawa, and senior author of the study. “Our study shows that muscle stem cells are ready to start repairing immediately, but immune cells keep the stem cells in a quiescent state while the cleanup is done. After about 40 hours, once the cleanup is complete, an internal alarm wakes the muscle stem cells and starts Repair.”
Dr. Dilworth and his team identified hyaluronic acid as the key ingredient in this internal alarm clock, which Can tell muscle stem cells when to wake up. When muscle damage occurs, stem cells begin to produce and coat themselves with hyaluronic acid. Once the coating became thick enough, it blocked sleep signals from immune cells and caused muscle stem cells to wake up.
Using mouse and human tissue, Dr. Dilworth and his team also discovered how muscle stem cells use the Has2 gene on the epigenetic marks to control hyaluronic acid production.