Abstract
A deeper insight into the mechanisms responsible for athlete performance that may serve as specific and detailed training indicators is still desired, because conventionally used biomarkers provide limited information about the adaptive processes that occur during exercise. The objective of our study was to assess insulin-like growth factor 1 receptors (IGF1R) gene expression and evaluate plasma concentration of selected microRNAs (miRNAs) during a 10-week training period (sampling times: week 1, 4, 7, and 10) in a group of 12 professional female volleyball players. Circulating miRNAs (miR-223, miR-320a, and miR-486) with established concentration in plasma and documented association with the IGF1 signaling pathway, which is involved in muscle development and recovery, were tested. The levels of analyzed miRNAs, tested by one-way ANOVA, were significantly different between four training periods during a 10-week training cycle (miR-223 p < 0.0001, miR-320a p = 0.00021, miR-486 p = 0.0037, respectively). The levels of IGF1R also appeared to be different (p = 0.00092), and their expression showed a trend to increase between the first and third periods. In the fourth period, the expression decreased, although it was higher compared with the baseline. Correlations between concentration levels of miR-223 and miR-320a (rs = 0.54, p < 0.001), as well as between miR-320a and miR-486 (rs = 0.73, p < 0.001) were also found. In the fourth period, a negative correlation between miR-223 plasma level and leucocyte IGF1R expression was found (rs = −0.63, p = 0.028). Multiple linear regression analysis showed that miR-320a (p = 0.024) and creatine kinase (p = 0.028) had the greatest impact on the expression levels of the IGF1R gene. Future studies are required to define whether these miRNAs, especially miR-320a, as well as IGF1R expression could be useful biomarkers of physiological changes during exercise and to discover their detailed biological roles in mode-specific exercise training adaptations of professional athletes.
Highlights
The recognition of epigenetic mechanisms may serve as a new factor for better understanding, monitoring, and optimizing athlete performance during training and season periods
The levels of insulin-like growth factor 1 receptors (IGF1R) showed to be different between the trainings (p = 0.00092), and expression of the mentioned gene showed a trend to increase between the first and third periods
The main finding of the study shows the alterations in the levels of all miRNAs and IGF1R expression within the training cycles, which reveals that miRNAs can be sensitive and reliable biomarkers of physical alteration
Summary
The recognition of epigenetic mechanisms may serve as a new factor for better understanding, monitoring, and optimizing athlete performance during training and season periods. IGF-1 affects almost every tissue in the human body by promoting cell proliferation, growth, and maturation through upregulation of anabolic processes [5,6]. IGF1R is activated by ligand binding and initiation of receptor tyrosine kinase that leads to conformational changes of the receptor This results in the activation of downstream signaling pathways of IGF-1, including Ras-mitogen-activated protein kinase pathway and phosphatidylinositol 3-kinase pathway, and cell proliferation, differentiation, and survival [14]. IGF1R molecules are present on the surface of leucocytes, known as cell differentiation marker CD221 They mediate communication within the immune system in the muscle regeneration process. Secretion of the IGF-1 and expression of its receptor in the blood by monocytes and granulocytes were identified as an important process related to muscle repair [15]. Due to its proliferation-promoting action, IGF1R has been investigated in many studies as a target in anticancer therapy [22,23]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
