Evaluation of circulating miRNAs during late pregnancy in the mare.
Authors: Loux Shavahn C, Scoggin Kirsten E, Bruemmer Jason E, Canisso Igor F, Troedsson Mats H T, Squires Edward L, Ball Barry A
Journal: PloS one
Summary
# Circulating microRNAs as Pregnancy Biomarkers in Mares MicroRNAs (miRNAs) are small regulatory RNA molecules shed into the bloodstream by tissues throughout the body, with circulating profiles that reflect physiological states and potentially disease conditions; whilst these biomarkers have proven diagnostically valuable in human obstetrics for detecting pregnancy complications such as chorioamnionitis and eclampsia, their role in equine reproduction remained unexplored. Researchers collected serial blood samples from pregnant mares at 8, 9 and 10 months of gestation and post-partum, alongside non-pregnant controls, screening a panel of 178 miRNAs using quantitative PCR to identify pregnancy-associated changes. Five miRNAs emerged as significant markers: miR-374b showed differential expression across late gestation, whilst miR-454, miR-133b, miR-486-5p and miR-204b differentiated pregnant from non-pregnant mares. Bioinformatic analysis predicted these differentially regulated miRNAs target pathways involved in endocrine signalling (GnRH, prolactin and insulin) as well as intracellular cascades (STAT3 and PI3/AKT pathways) crucial to maintaining pregnancy. These findings establish baseline data for normal equine pregnancy that could underpin development of non-invasive blood-based screening tools for identifying mares at risk of pregnancy complications or parturition timing, offering clinicians a complementary diagnostic approach to existing reproductive monitoring techniques.
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Practical Takeaways
- •Circulating miRNA panels could potentially be developed as non-invasive diagnostic tools to detect pregnancy complications in mares, reducing need for invasive testing
- •These biomarkers may help identify mares at risk of pregnancy loss or other gestation-related complications before clinical signs appear
- •Further research is needed to establish clinical utility and validate these miRNAs as practical diagnostic markers for equine reproduction
Key Findings
- •Five miRNAs showed differential regulation during late pregnancy or between pregnant and non-pregnant mares: miR-374b, miR-454, miR-133b, miR-486-5p, and miR-204b
- •Predicted targets of pregnancy-regulated miRNAs are involved in STAT3, PI3/AKT, GnRH, prolactin, and insulin signaling pathways
- •Circulating miRNAs may serve as non-invasive biomarkers for assessing pregnancy status and complications in mares