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bioRxiv · 10.1101/721928

Systematic assessment of blood-borne microRNAs highlights molecular profiles of endurance sport and carbohydrate uptake

Abstract

Multiple studies endorsed the positive effect of regular exercising on mental and physical health. However, the molecular mechanisms underlying training-induced fitness in combination with personal life-style remain largely unexplored. Circulating biomarkers such as microRNAs (miRNAs) offer themselves for studying systemic and cellular changes since they can be collected from the bloodstream in a low-invasive manner. In Homo sapiens miRNAs are known to regulate a substantial number of protein-coding genes in a post-transcriptional manner and hence are of great interest to understand differential gene expression profiles, offering a cost-effective mechanism to study molecular training adaption, and connecting the dots from genomics to observed phenotypes.\n\nHere, we investigated molecular expression patterns of 2, 549 miRNAs in whole-blood samples from 23 healthy and untrained adult participants of a cross-over study, consisting of 8 weeks of endurance training, with several sessions per week, followed by 8 weeks of washout and another 8 weeks of running, using microarrays. Participants were randomly assigned to one of the two study groups, one of which administered carbohydrates before each session in the first training period, switching the treatment group for the second training period. During running sessions clinical parameters as heartbeat frequency were recorded. This information was extended with four measurements of maximum oxygen uptake (VO2 max) for each participant.\n\nWe observed that multiple circulating miRNAs show expression changes after endurance training, leveraging the capability to separate the blood samples by training status. To this end, we demon-strate that most of the variance in miRNA expression can be explained by both common and known biological and technical factors. Our findings highlight six distinct clusters of miRNAs, each exhibiting an oscillating expression profile across the four study timepoints, that can effectively be utilized to predict phenotypic VO2 max levels. In addition, we identified miR-532-5p as a candidate marker to determine personal alterations in physical training performance on a case-by-case analysis taking the influence of a carbohydrate-rich nutrition into account. In literature, miR-532-5p is known as a common down-regulated miRNA in diabetes and obesity, possibly providing a molecular link between cellular homeostasis, personal fitness levels, and health in aging.\n\nWe conclude that circulating miRNAs expression can be altered due to regular endurance training, independent of the carbohydrate availability in the timeframe around training. Further validation studies are required to confirm the role of exercise-affected miRNAs and the extraordinary function of miR-532-5p in modulating the metabolic response to a high availability of glucose.

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BibTeXRIS

Kern, F., Ludwig, N., Backes, C., Maldener, E., Fehlmann, T., Suleymanov, A., Meese, E., Hecksteden, A., Keller, A., Meyer, T.. 2019-08-01. Systematic assessment of blood-borne microRNAs highlights molecular profiles of endurance sport and carbohydrate uptake. https://doi.org/10.1101/721928

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