Exercise‐enriched extracellular vesicles benefit brain health by decreasing protein aggregation

Abstract

Aerobic exercise results in improved brain health during both healthy aging and dementia. However, the precise biological mechanisms that drive exercise‐induced benefits for brain health remain unknown. One possible mechanism by which exercise may benefit the brain is by facilitating the delivery of molecular mediators within extracellular vesicles (EVs; exosomes and microvesicles). EVs are bilayer‐phospholipid enclosed vesicles that carry protein and microRNA cargo and are released into the blood from many organs and cells. EVs have been shown to regulate nerve regeneration, synaptic function and behavior. Importantly, when directly injected into rodent brains, EVs can effectively eliminate protein aggregates like amyloid‐β‐peptide (Aβ), which are closely linked to Alzheimer’s Disease (AD) pathology. We hypothesize that EVs isolated from human serum post‐exercise could effectively clear Aβ aggregates in neuronal cells. To test this hypothesis, we isolated EVs from cognitively healthy subjects and early onset AD subjects (8 non‐dementia subjects, ND and 4 early AD subjects) 15 minutes after maximal aerobic exercise (EX). EV size did not change with exercise in either ND or AD subjects, while EV concentration increased by 20% post‐EX in both groups. EV function was tested by incubating serum EVs with human neuronal SY5Y cells over expressing β‐amyloid precursor protein (APPswe). We found that post‐EX‐derived EVs were more effective at alleviating Aβ protein aggregation (40% decrease in aggregation compared to pre‐EX‐derived EVs). Heat Shock Proteins (HSPs), molecular chaperones that play a critical role in protein folding/misfolding, were increased in post‐EX EVs. These findings demonstrate a novel way in which exercise could benefit the brain, through the cell‐to‐cell signaling network of extracellular vesicle communication.Support or Funding InformationResearch support by the University of Kansas Alzheimer’s Disease Center.