Seminal plasma modulates miRNA expression by sow genital tract lining explants

The seminal plasma (SP) modulates the female reproductive immune environment after mating and microRNAs (miRNAs) could participate in the process. Considering the boar ejaculate is built by fractions differing in SP-composition; this study evaluated whether exposure of mucosal explants of the sow internal genital tract (uterus, utero-tubal junction and isthmus) to different SP-fractions changed the profile of explant-secreted miRNAs. Mucosal explants retrieved from oestrus sows (n=3) were in vitro exposed to: Medium 199 (M199, Control) or M199 supplemented (1:40 v/v) with SP from the sperm-rich fraction (SRF), the post-SRF or the entire recomposed ejaculate, for 16 h. After, the explants were cultured in M199 for 24 h to finally collect the media for miRNA analyses using GeneChip miRNA 4.0 Array (Affymetrix). Fifteen differentially expressed (False‐Discovery-Rate < 0.05 and Fold-change ≥ 2) miRNAs (11 down- vs 4 up-regulated) were identified (the most in the media of uterine explants incubated with SP from post-SRF). Bioinformatics analysis identified that predicted target genes of dysregulated miRNAs, mainly miR-34b, miR-205, miR-4776-3p and miR-574-5p, were involved in functions and pathways related to immune response. In conclusion, SP is able to elicit changes in the miRNAs profile secreted by female genital tract, ultimately depending SP-composition. In vitro exposure of mucosal explants of the internal genital tract of three oestrus sows (uterus, utero-tubal junction [UTJ] and isthmus) to Medium 199 (M199) alone or M199 supplemented with SP from different fractions (i.e. the sperm-rich fraction [SRF], the post-SRF) or a composite (recomposed entire ejaculate [EE]) for 16 h. After, the explants were cultured in M199 for 24 h to finally collect the media for miRNA analyses using GeneChip miRNA 4.0 Array (Affymetrix).