Kinetics and topology of DNA associated with circulating extracellular vesicles released during exercise

Abstract

Although it is widely accepted that cancer derived extracellular vesicles (EVs) carry DNA cargo, the association of cell-free circulating DNA (cfDNA) and EVs in plasma of healthy humans remains elusive. Using a physiological exercise model, where EVs and cfDNA are synchronously released, we aimed to characterize the kinetics and localization of DNA associated with EVs. EVs were separated from human plasma using size exclusion chromatography or immuno-affinity capture for CD9+, CD63+, and CD81+ EVs. DNA was quantified with an ultra-sensitive qPCR assay targeting repetitive LINE elements, with or without DNase digestion. This model shows that a minute part of circulating cell-free DNA is associated with EVs. During rest and following exercise, only 0.12 % of the total cfDNA occurs in association with CD9+/CD63+/CD81+EVs. DNase digestion experiments indicate that the largest part of EV associated DNA is sensitive to DNase digestion and only ~20 % are protected within the lumen of the separated EVs. A single bout of running or cycling exercise increases the levels of EVs, cfDNA, and EV associated DNA. While EV surface DNA is increasing, DNAse-resistant DNA remains at resting levels, indicating that EVs released during exercise (ExerVs) do not contain DNA. Consequently, DNA is largely associated with the outer surface of circulating EVs. ExerVs recruit cfDNA to their corona, but do not carry DNA in their lumen.

Ageing related thyroid deficiency increases brain-targeted transport of liver-derived ApoE4-laden exosomes leading to cognitive impairments

“…Decreased THs secretion in ageing affects expression of CD9 and CD81 in exosomes, which in turn modi es exosomal transport. Both CD9 and CD81 are the protein markers of exosomes 21 , they belong to tetranspanin family modulating exosomal adhesion strengthening 22 . In this work, we discovered that increase in CD9 and decrease in CD81 associated with ageing may promote exosomal transport by changing the exosomal adhesion function.…”

Physical activity specifically evokes release of cell-free DNA from granulocytes thereby affecting liquid biopsy

“…4,5 Exercise impacts immune homeostasis and leads to rapid and markedly increased levels of cfDNA in blood. Depending on exercise modality, duration, and intensity cfDNA increases 2-20 fold, [6][7][8][9] and even submaximal levels leads to 2-4 fold increases, 10 showing a half-life of ~15 min. 6,9 Exerciseinduced cfDNA releases could interfere with, or improve the diagnostic accuracy of methylation specific testing, depending on whether the DNA is derived from the clinically relevant cell type.…”

“…4,5 Exercise impacts immune homeostasis and leads to rapid and markedly increased levels of cfDNA in blood. Depending on exercise modality, duration, and intensity cfDNA increases 2-20 fold, 6–9 and even submaximal levels leads to 2-4 fold increases, 10 showing a half-life of ∼15 min. 6,9 Exercise-induced cfDNA releases could interfere with, or improve the diagnostic accuracy of methylation specific testing, depending on whether the DNA is derived from the clinically relevant cell type.…”