Sedentary and Trained Older Men Have Distinct Circulating Exosomal microRNA Profiles at Baseline and in Response to Acute Exercise.
Author(s): Nair VD, Ge Y, Li S, Pincas H, Jain N, Seenarine N, Amper MAS, Goodpaster BH, Walsh MJ, Coen PM, Sealfon SC
Publication: Front Physiol, 2020, Vol. 11, Page 605
PubMed ID: 32587527 PubMed Review Paper? No
Purpose of Paper
The purpose of this paper was to compare the effects of exercise on the microRNA (miRNA, miR) signatures of trained and sedentary older men by next generation sequencing (NGS).
Conclusion of Paper
As expected, steady state VO2 and power output were greater in trained than sedentary individuals but percentage heart rate reserve and VO2 max as well as respiratory quotient were comparable between groups. The majority of the RNA isolated from the exosomes (60-80%) was 22 nt long and susceptible to RNAse treatment but not DNAase. The total number of reads, the percentage of mappable reads, and the percentage of reads mapping to the human genome/transcriptome were comparable between groups. miRNA expression differed between groups at each timepoint examined and the lists of miRNA altered by exercise were completely different in trained and sedentary men. Interestingly, with two exceptions, miRNA found to be differentially expressed by exercise in either group were only affected at one timepoint (immediately following exercise of 3 h post-exercise). Pathway analysis showed differential activation of the I-GF1 signaling pathway at baseline in the two groups. Interestingly, while exercise increased IGF-1 and tumor suppression following exercise in the active group, it caused decreased IGF-1 signaling in the sedentary group.
Studies
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Study Purpose
The purpose of this study was to compare the effects of exercise on the miRNA signatures of trained and sedentary older men. PAXgene blood was collected from five active (running or cycling an unspecified times per week for 5 years) and five sedentary (< 1 exercise bout per week) healthy older (>65) men after fasting (pre-exercise). Patients then ate a low glycemic index meal and cycled for 40 min at 70% heart rate reserve after which blood was drawn immediately and again after 3 h. Plasma was obtained by centrifugation at 3,000 x g for 10 min at room temperature and stored at -80°C. Exosomes were isolated from plasma thawed on ice by centrifugation at 3000 x g for 15 min at 4°C, incubation of the supernatant with Thromboplastin D for 15 min at 37°C, centrifugation at 13000 x g for 10 min at 4°C, incubation of the supernatant with Exoquick and RNAse overnight at 4°C, followed by centrifugation at 1500 x g for 25 min at 4°C. The pellets were resuspended in PBS and stored at -20°C. Particle size was evaluated by nanoparticle tracking analysis. RNA was isolated from exosomes following QIAzol lysis and chloroform separation using RNeasy. RNA was evaluated using a bioanalyzer. Sequencing libraries were prepared using the NEBNext Small RNA Library Prep Set and sequenced on an Illumina MiSeq and processed using the exceRpt Pipeline.
Summary of Findings:
As expected, steady state volume of oxygen consumption (VO2) and power output were greater in trained than sedentary individuals (P<0.001, both) but percentage heart rate reserve and VO2 max as well as respiratory quotient were comparable between groups. The purified extracellular vesicles ranged from 68-105 nm, indicating they contained mostly exosomes. The majority of the RNA isolated from the exosomes (60-80%) was 22 nt long and susceptible to RNAse treatment but not DNAase. The total number of reads, the percentage of mappable reads, and the percentage of reads mapping to the human genome/transcriptome were comparable between groups. The reads mapped to a variety of RNA species with 28.69% ± 8.76% mapping to miRNA. The miRNA reads corresponded to a total of 371 ± 71 different miRNAs. miRNA expression differed between groups at each timepoint examined. At baseline, miR-486-5p, miR-215-5p, and miR-941 were upregulated and miR-151b downregulated in the plasma exosomes of trained versus sedentary men. In the plasma exosomes of trained men, levels of miR-383-5p, miR-339-5p, and miR-874-3p increased and levels of miR-206, miR-486-5p, miR-148a-3p, and let-7b-5p decreased immediately following exercise. By 3 h post-exercise, only miR-486-5p was still decreased relative to baseline, bringing it close to the baseline levels in untrained men, but new increases in miR-34b-3p, miR-129-2-3p, miR-138-1-3p, miR-671-3p, and miR-885-5p and decreases in miR-486-5p, miR-629-5p, and miR-16-2-3p relative to baseline were observed. In the plasma exosomes of untrained men, levels of miR-505-3p, miR-29b-3p, miR-203a-3p, miR-384, miR-451a, miR-223-3p, miR-218-5p, and miR-495-3p were increased and miR-4433b-3p decreased immediately after exercise. The observed decrease in miR-4433b-3p was still observed 3 h after exercise compared to baseline but levels of mir-378c, miR-151b, miR-151a-5p, and hsa-miR-151b were also decreased. Importantly, the lists of miRNA altered by exercise showed no overlap between trained and sedentary men. Pathway analysis showed differential activation of the IGF-1 signaling pathway at baseline in the two groups. Interestingly, while exercise increased IGF-1 and tumor suppression following exercise in the active group, it caused decreased IGF-1 signaling in the sedentary group.
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Normal
Platform:
Analyte Technology Platform RNA Next generation sequencing RNA Automated electrophoresis/Bioanalyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Acquisition Time of biospecimen collection Baseline (Pre-exercise)
Immediately after exercise
3 h post-exercise
Preaquisition Diagnosis/ patient condition Trained
Sedentary