Exercise Facilitates Stem Cell Appearance in Skeletal Muscle

Mesenchymal stem cells (green florescence) are found in several locations in skeletal muscle, including around blood vessels following exercise. (Image courtesy of Marni Boppart)
Mesenchymal stem cells (green florescence) are found in several locations in skeletal muscle, including around blood vessels following exercise. (Image courtesy of Marni Boppart)

Marni Boppart of the Bioimaging Science and Technology group and her collaborators have found that a single bout of exercise in mice leads to an increase in mesenchymal stem cells (MSCs) that reside in skeletal muscle, a finding that could provide insight into the link between exercise and whole body health.

Researchers have found that a single bout of exercise in mice leads to an increase in mesenchymal stem cells (MSCs) that reside in skeletal muscle, a finding that could provide insight into the link between exercise and whole body health.

Marni Boppart of the Bioimaging Science and Technology group and her collaborators have shown for the first time that just one exercise session in mice leads to an accumulation of what are called muscle-derived mesenchymal stem cells (or mMSCs) that play a role in regeneration response to injury or disease in skeletal muscle.

Mesenchymal stem cells are found throughout the body and can differentiate into a variety of cell types, including for enhancement of tissue regeneration. In addition to that role, they can indirectly facilitate tissue healing, as was found in this study.  

“What we’ve been able to show in this paper and our current work is that mMSCs are not directly contributing to muscle growth, but do in fact secrete a variety of different factors that positively impact muscle growth” Boppart said. “The cells usually respond to injury but in the case of exercise what we think, and this is a very novel phenotype for these cells, is that they secrete the factors specifically in response to mechanical strain.

"We are very excited because this work is an important step towards developing effective interventions that can prevent the loss of muscle that occurs with aging and disease.”

Boppart is an Assistant Professor in the Department of Kinesiology and Community Health awhose works focuses on the molecular and cellular mechanisms responsible for musculoskeletal remodeling and growth in response to exercise and mechanical strain.

Boppart and her collaborators reported their work last week in the journal PlosOne. They wrote about the importance of maintaining skeletal muscle mass for overall health, especially when it comes to exercise or rehabilitation activities, and why it’s important to understand the body’s responses to factors like exercise and injury: “Engagement in physical activity or rehabilitation therapy can preserve muscle mass and function. Therefore, identification of the critical mechanisms that underlie beneficial adaptations to physical activity can be informative in the development of effective molecular- or cell-based therapies.”

In addition to their finding on the effect of exercise on mMSCs, the researchers were able to define a critical role for the α7 integrin receptor (a molecule that mediates connections between cells and tissues) in mMSC accumulation, characterize the cells as predominantly pericytes, and demonstrate the regulation of cell surface expression by mechanical strain.