Understanding how exercise induces systemic metabolic benefits

Scientists at Northwestern Medicine have uncovered a mechanism by which exercise activates metabolic effects in the body, according to a new study published in . cell metabolism.

It is well known that exercise elicits many health benefits. However, it is still not well understood how this is achieved. During exercise, autophagy, the body’s cellular recycling system that allows the breakdown of old or damaged cellular structures, is activated both in contracting muscles and in various non-contractile organs such as the liver.

In this study, researchers performed proteomic analysis on the blood of mice before and after exercise. They identified a protein secreted from muscle contraction, FN1, that was significantly increased in mouse plasma and serum after exercise.

The scientists next analyzed how FN1 communicates with the liver. They found that FN1 signals through the a5b1 integrin, a membrane receptor in the liver, triggering autophagy and eliciting the metabolic benefits of exercise. We found that mice lacking the FN1 gene in muscle develop insulin resistance despite daily exercise.

The findings help us better understand exercise and how it benefits metabolism, said Dr. Congcong He, associate professor in Cell and Developmental Biology and senior author of the study.

“We wanted to understand exercise-induced autophagy, especially in non-contractile tissues like the liver,” said He, who is also a member of the Robert H. Lurie Comprehensive Cancer Center at Northwestern University. said. “This will not only improve our understanding of the mechanisms underlying how exercise induces metabolic effects systemically, but also how muscle secretions act on the liver. We have now identified FN1 as a mediator of exercise-induced effects through the muscle liver: communication of autophagy.”

In the future, he and collaborators hope to further analyze FN1 to understand which elements of the protein activate post-exercise metabolic effects.

“The protein is quite large, so we want to chop it up into smaller peptides to see which ones are bioactive.” It could be developed, for example, to use this molecule as an insulin sensitization treatment.”