Wednesday, November 13, 2024

When muscles work out, they help neurons to grow, a new study shows

Amazing stuff! Exercise more!

"... Now, MIT engineers have found that exercise can also have benefits at the level of individual neurons. They observed that when muscles contract during exercise, they release a soup of biochemical signals called myokines. In the presence of these muscle-generated signals, neurons grew four times farther compared to neurons that were not exposed to myokines. These cellular-level experiments suggest that exercise can have a significant biochemical effect on nerve growth.

Surprisingly, the researchers also found that neurons respond not only to the biochemical signals of exercise but also to its physical impacts. The team observed that when neurons are repeatedly pulled back and forth, similarly to how muscles contract and expand during exercise, the neurons grow just as much as when they are exposed to a muscle’s myokines. ..."

From the abstract:
"Emerging in vivo evidence suggests that repeated muscle contraction, or exercise, impacts peripheral nerves. However, the difficulty of isolating the muscle-specific impact on motor neurons in vivo, as well as the inability to decouple the biochemical and mechanical impacts of muscle contraction in this setting, motivates investigating this phenomenon in vitro. This study demonstrates that tuning the mechanical properties of fibrin enables longitudinal culture of highly contractile skeletal muscle monolayers, enabling functional characterization of and long-term secretome harvesting from exercised tissues. Motor neurons stimulated with exercised muscle-secreted factors significantly upregulate neurite outgrowth and migration, with an effect size dependent on muscle contraction intensity. Actuating magnetic microparticles embedded within fibrin hydrogels enable dynamically stretching motor neurons and non-invasively mimicking the mechanical effects of muscle contraction. Interestingly, axonogenesis is similarly upregulated in both mechanically and biochemically stimulated motor neurons, but RNA sequencing reveals different transcriptomic signatures between groups, with biochemical stimulation having a greater impact on cell signaling related to axonogenesis and synapse maturation. This study leverages actuating extracellular matrices to robustly validate a previously hypothesized role for muscle contraction in regulating motor neuron growth and maturation from the bottom-up through both mechanical and biochemical signaling."

When muscles work out, they help neurons to grow, a new study shows | MIT News | Massachusetts Institute of Technology "The findings suggest that biochemical and physical effects of exercise could help heal nerves."

 
In response to biochemical and physical cues of exercise, motor neurons (in purple) exhibit new growth (in green) faster than neurons that experience no exercise-induced cues.


MIT scientists find that motor neuron growth increased significantly over 5 days in response to biochemical (left) and mechanical (right) signals related to exercise. The green ball represents cluster of neurons that grow outward in long tails, or axons.


Fig 1 Tuning fibrin hydrogel mechanical properties for long-term muscle monolayer culture.


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