Assistant professor of pathology at Stanford University, Jonathan Long, has said that the possibility that exercise prompts different cells in our body to produce molecules that benefit human health has long piqued the interest of researchers.
These molecules, also known as exercise factors or exerkines, have the potential to improve athletic performance and reduce the prevalence of diseases like obesity, heart disease, and diabetes if they can be isolated and used in pharmaceutical applications.
Long argues that this objective has been elusive because exerkines cannot be isolated from blood. But now, Long and his colleagues have developed a novel technique that can detect cell-secreted molecules much deeper in the blood. This method also elucidates which cell types produce which molecules, which is crucial for figuring out how exercise benefits health.
And now, thanks to Long’s innovative approach, an article was released in Cell Metabolism detailing the plethora of ways in which exercise modifies the secretion of proteins by 21 distinct rodent cell types. Some unexpected results came out of the work as well.
For starters, researchers were surprised by how many proteins were affected by physical activity. The researchers found that 21 cell types each differentially regulated the expression of nearly 200 exercise factors. The most exercise-responsive cells were a type of cell that is poorly understood and is named for a specific protein receptor (Pdgfra) that is present in a wide variety of tissues and organs. Muscle, bone, and liver cells—the usual suspects—showed only moderate responses, according to Long.
In addition, the group was taken aback to learn that exercise causes only liver cells to secrete several members of the carboxylesterase family of proteins. Although studies on their cellular roles have demonstrated their positive effects on metabolic health, no clear role for these proteins in the circulatory system had previously been observed.
Long’s group engineered mice to secrete elevated levels of carboxylesterase proteins from the liver without exercise to investigate their function. Furthermore, the rodents showed enhanced treadmill endurance and resisted weight gain when fed a high-fat diet.