Identification and analysis of differentially expressed microRNAs in endometrium to explore the regulation of sheep fecundity.

BACKGROUND: MicroRNAs (miRNAs) play an important regulatory role in mammalian reproduction. Currently, most studies are primarily concentrated on ovarian miRNAs, ignoring the influence of endometrial miRNAs on the fecundity of female sheep. To uncover potential regulators of sheep fecundity, RNA-seq was used to comparatively analyze miRNA expression profiles of endometrium between high prolificacy sheep (HP, litter size = 3) and low prolificacy sheep (LP, litter size = 1) with FecB genotype. RESULTS: Firstly, genomic features of miRNAs from endometrium were analyzed. Furthermore, 58 differentially expressed (DE) miRNAs were found in the endometrium of Hu sheep with different litter size. A co-expression network of DE miRNAs and target genes has been constructed, and hub genes related litter size are included, such as DE miRNA unconservative_NC_019472.2_1229533 and unconservative_NC_019481.2_1637827 target to estrogen receptor α (ESR1) and unconservative_NC_019481.2_1637827 targets to transcription factor 7 (TCF7). Moreover, functional annotation analysis showed that the target genes (NRCAM and NEGR1) of the DE miRNAs were significantly enriched in cell adhesion molecules (CAMs) signaling pathway, which was related to uterine receptivity. CONCLUSION: Taken together, this study provides a new valuable resource for understanding the molecular mechanisms underlying Hu sheep prolificacy.