Summary: Researchers discovered a critical link between exercise, muscle function and brain health. Their study reveals that the nerves that activate muscles during exercise also trigger the release of molecules that improve brain function.
By stimulating these nerves with glutamate, they found that the innervated muscles produced more hormones that drive the brain and extracellular vesicles. This research underscores the importance of maintaining neuromuscular health, especially as we age, to support overall brain and organ function.
Key factors:
- Influence of neurons on muscle secretions: Muscles innervated by neurons produce more substances that promote brain health compared to non-innervated muscles.
- Impact of glutamate on muscle activation: Glutamate stimulation increases the secretion of beneficial hormones such as irisin and enhances the release of extracellular vesicles containing microRNAs that support neurodevelopment.
- Implications for aging and neuromuscular health: The study highlights the critical role of neuron-muscle interactions in maintaining cognitive function, particularly relevant to aging populations and those with neuromuscular disorders.
Source: University of Illinois
Exercise causes muscles to release molecular cargo that increases the function and connection of brain cells, but the process is not well understood. New research from the University of Illinois Urbana-Champaign has found that the nerves that tell muscles to move also induce them to release more brain-enhancing factors.
“Molecules released from the muscle go into the bloodstream and then into the brain, producing so-called muscle-brain crosstalk. But the muscle itself is highly innervated.
“So we asked ourselves, what is the effect of neurons on this muscle activity and, downstream, on muscle-brain communication?” said chemical and biomolecular engineering professor Hyunjoon Kong, leader of the study published in theProceedings of the National Academy of Sciences.
“As we get older, we lose these neurons in the muscle. And some people also lose these neurons due to disease or injury. So understanding their role and how these nerves in the muscle affect the brain is important for older people or patients with neuromuscular injuries and diseases,” he said.
Exercise research has found that muscles secrete hormones and extracellular vesicles, small packets that transport molecules between cells, containing small pieces of RNA that improve connection, signal transmission and communication between brain cells
However, while much attention has been paid to the function of muscle-derived factors, the role of the nerves that stimulate the muscle is poorly understood, said graduate student Kai-Yu Huang, the first author of the study.
To fill this gap, the researchers compared two models of muscle tissue, one with neuronal innervation and one without. They found that innervated muscle produced more molecules that promote brain neuron activity and regulate muscle development than unnerved muscle.
The researchers then stimulated the nerves with glutamate, a neurotransmitter. They found that the innervated muscle had greater expression of a gene important for regulating secretion.
Consequently, it emitted higher levels of the hormone irisin, which is associated with the beneficial effects of exercise, and released more extracellular vesicles than plain muscle.
“We analyzed the cargo carried in the vesicles and found that there was a greater diversity of microRNAs associated with the impact on neurodevelopment,” Huang said.
“These findings highlight the importance of neuron innervation. As we age, we lose nerve input to muscles and our muscles begin to break down and lose function. And in some ways, this can still lead to plus an organ dysfunction. So understanding how to regulate or maintain the secretory behavior of the muscle is very important.”
Next, the researchers plan to further investigate the mechanisms at the junction where neurons meet muscle cells to determine how nerve impulses stimulate the muscle and whether they affect the production of the factors that drive the brain or just their release. an important distinction for possible treatments. for those who have lost nerves or muscles.
They also hope to explore the use of their tissue model as a platform to efficiently produce the factors. Ultimately, they hope to have a complete picture of the brain-nerve-muscle loop and how to maintain it.
“It’s our individual organs talking to each other: the brain tells the nerves to stimulate the muscle, and the muscle then releases molecules that are beneficial for brain function,” Kong said.
“It highlights the importance of exercise. Exercise creates a more robust interface between motor neurons and muscle, and we now know that the nerves that send the signal to the muscle release extracellular molecules and vesicles that are beneficial to the brain
“So we might look at the benefits of exercise focused on fostering that connection rather than simply increasing muscle volume or strength.”
About this exercise and neuroscience research news
Author: Liz Ahlberg Touchstone
Source: University of Illinois
Contact: Liz Ahlberg Touchstone – University of Illinois
Image: Image credited to Neuroscience News
Original search: Closed access
“Neural innervation regulates the secretion of myokines and neurotrophic exosomes from skeletal muscle” by Kai-Yu Huang et al. PNAS
Summary
Neuronal innervation regulates the secretion of myokines and neurotrophic exosomes from skeletal muscle.
Myokines and exosomes, originating from skeletal muscle, are shown to play an important role in maintaining brain homeostasis.
Although exercise has been reported to promote muscle secretion, little is known about the effects of neural innervation and activity on the performance and molecular composition of biologically active molecules in muscle.
Because neuromuscular diseases and denervation-associated disabilities affect muscle metabolism, it is hypothesized that neuronal innervation and firing may play a critical role in the regulation of skeletal muscle secretory activities.
We examined this hypothesis using an engineered neuromuscular tissue model consisting of skeletal muscles innervated by motor neurons.
Innervated muscles showed elevated expression of mRNAs encoding neurotrophic myokines, such as interleukin-6, brain-derived neurotrophic factor, and FDNC5, as well as peroxisome proliferator-activated receptor coactivator 1 mRNA, a key regulator of muscle metabolism
After glutamate stimulation, innervated muscles secreted higher levels of irisin and exosomes containing more diverse neurotrophic microRNAs than neuron-free muscles.
Accordingly, biological factors secreted by innervated muscles enhanced branching, axonal transport, and ultimately spontaneous network activities of primary hippocampal neurons in vitro.
Overall, these results reveal the importance of neuronal innervation in modulating muscle-derived factors that promote neuronal function and suggest that the engineered neuromuscular tissue model holds significant promise as a platform for producing neurotrophic molecules.
#Exercise #improves #brain #function #musclenerve #interaction #Neuroscience #News
Image Source : neurosciencenews.com