The Redox Enzyme Thioredoxin is Increased in Plasma Extracellular Vesicles from Endurance-Trained Females in Response to Acute Exercise

The effects of exercise are mediated by molecules secreted into the circulation in response to exercise. Extracellular vesicles (EVs) have recently appeared as possible vehicles for some of these molecules, and as mediators of tissue crosstalk during exercise. This study aimed to identify changes in the proteome of EVs released into circulation by endurance running-trained females after a bout of 60-min aerobic exercise consisting of incremental treadmill running. Blood samples were collected immediately before and after exercise, and EVs were separated from plasma and characterized by Western blot and electron microscopy. Mass spectrometry-based proteomics analysis of EV preparations was then performed and showed that the levels of 9 proteins were differentially expressed in response to exercise. Thioredoxin, an enzyme that plays an essential role in the maintenance of redox homeostasis, showed the largest change. The increase in the levels of thioredoxin after exercise was also observed by Western blot analysis. Interestingly, post-exercise plasma EVs were able to protect cells against oxidative stress. These results support the effect of physical exercise in modulating the levels of molecules involved in the maintenance of redox homeostasis, such as thioredoxin and other antioxidant enzymes, in plasma EVs. Although further studies are needed to fully understand the functional role of these molecules, it is intriguing to consider the protective health effects that exercise-induced EVs may have against oxidative stressors.