Changes in Circulating MicroRNA Profiles During Arctic Military Training Target Inflammatory Pathways Independent of...

Area of Science:

• Exercise physiology
• Molecular biology
• Nutritional science

Background:

• Circulating microRNAs (c-miRNAs) are responsive to physiological stressors like exercise and energy status.
• Understanding c-miRNA changes during intense training and their modulation by diet is crucial for optimizing performance and health.
• The specific impact of varying macronutrient intake on c-miRNA during Arctic military training remains unexplored.

Purpose of the Study:

• To investigate the effect of essential amino acid-dense (EAA-Dense), energy-dense high-fat (EN-Dense), and high-carbohydrate (CHO) supplemental nutrition on c-miRNA profiles during Arctic military training.
• To determine if dietary macronutrient composition influences the regulatory function of c-miRNAs in response to extreme environmental conditions and physical exertion.

Main Methods:

• Soldiers underwent an 8-day Arctic training regimen, receiving standard rations plus one of three supplemental snack bars (EAA-Dense, EN-Dense, or CHO).
• Macronutrient intake was meticulously tracked daily. Circulating microRNAs (c-miRNAs) were quantified using RT-qPCR before and after training.
• Bioinformatics and in vitro analyses identified the functional role of significantly altered c-miRNAs, focusing on miR-146a-5p.

Main Results:

• No significant differences in overall energy intake were observed across groups.
• While specific macronutrient intakes varied as intended (highest protein in EAA-Dense, fat in EN-Dense, carbohydrate in CHO), the type of supplemental nutrition did not alter c-miRNA profiles.
• Twenty-six c-miRNAs showed significant changes from pre- to post-training, irrespective of the dietary intervention. MiR-146a-5p demonstrated the most pronounced change and was found to target inflammatory signaling pathways.

Conclusions:

• MiR-146a-5p plays a significant role in regulating inflammatory responses to physiological stress during intense training.
• Dietary macronutrient composition, within the tested parameters, did not influence the observed changes in c-miRNA profiles or the function of miR-146a-5p.
• This study identifies miR-146a-5p as a potential biomarker and therapeutic target for managing inflammation in physically stressed individuals.