Micro-RNA (miRNA) epigenetic profiling of plasma small extracellular vesicles (sEV) – sEV miRNA as diagnostic biomarker of fertility

Abstract Fertility is determined to a significant extent by its underlying genetics and success of pregnancy is considered as a tool to define fertility. A substantial knowledge gap exists however, regarding epigenetic abnormalities resulting in infertility. The accuracy of information concerning fertility is critical to the success of an infertility treatment plan. Here, the authors explore the use and the value of blood plasma small extracellular vesicle (sEV) derived micro-RNA (miRNA) as biomarkers of fertility. Next-generation miRNA sequencing identified 14 differentially expressed (DE) miRNAs expressed with a substantial confidence between low fertile (LF) sEV and high fertile (HF) sEV (FDR < 0.05 and -logFC > 2), isolated from plasma of dairy cows (n = 10 per each HF and LF group). Interestingly, the majority of DE miRNAs were uniquely packaged into sEV and not found in circulating plasma. Validation using qRT-PCR miRNA assays indicated similar expression patterns of miR-17-5p, miR-2285dd, miR-2335, miR-12054 and miR-2285aw, and confirmed that miR-181b-5p was significantly upregulated in LF sEV (P value = 0.0093, Fold change = 2.665). The results from this study suggest that circulating sEV miRNA reflect the overall fertility status including the physiological status of the endometrium. Moreover, miR-181b-5p was validated as a prognostic sEV miRNA biomarker of fertility.