Expression of microRNAs in Horse Plasma and Their Characteristic Nucleotide Composition.
Authors: Lee Seungwoo, Hwang Seungwoo, Yu Hee Jeong, Oh Dayoung, Choi Yu Jung, Kim Myung-Chul, Kim Yongbaek, Ryu Doug-Young
Journal: PloS one
Summary
# Editorial Summary Circulating microRNAs in equine blood plasma appear to possess distinct structural properties that may explain their remarkable stability in the presence of ribonucleases—enzymes that would normally degrade RNA—and their potential role in inter-tissue signalling. This 2016 study examined the nucleotide composition and expression profiles of 2,584 equine miRNA sequences, comparing those found in plasma with tissue-based miRNAs to identify whether circulating variants showed selective enrichment or compositional bias. The researchers discovered that the most abundant plasma miRNAs (eca-miR-486-5p, -92a, and -21) were largely absent from non-plasma tissues, with only the eca-let-7 family bridging both compartments; notably, these same species rank amongst the most abundant in human plasma, suggesting evolutionary conservation of a specific circulating miRNA signature. Plasma miRNAs demonstrated significantly higher proportions of adenine and cytosine repeat sequences compared to their tissue counterparts, despite cytosine overall being the least frequent nucleotide, whilst maintaining similar uracil and guanine levels. For equine practitioners, these findings suggest that circulating miRNA profiles could potentially serve as biomarkers reflective of systemic physiological state, though further investigation into how tissue injury, exercise, infection, or metabolic conditions alter these circulating signatures would be required before clinical application in diagnostics or monitoring becomes viable.
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Practical Takeaways
- •Plasma miRNAs may serve as biomarkers for disease detection and health monitoring in horses, given their stability and tissue-communication function
- •The identified characteristic nucleotide composition of equine plasma miRNAs (particularly eca-miR-486-5p, -92a, -21) could help develop diagnostic tools for equine health assessment
Key Findings
- •Highly expressed plasma miRNAs (eca-miR-486-5p, -92a, -21) differ from abundant tissue miRNAs except for eca-let-7 family
- •Horse plasma miRNA nucleotide composition is characterized by high uracil and guanine, low cytosine relative to non-plasma miRNAs
- •Plasma miRNAs show elevated adenine and cytosine repeat sequences compared to non-plasma miRNAs
- •Horse plasma miRNA composition patterns are conserved with human plasma miRNAs, suggesting evolutionary significance