Dynamic microRNA expression profiles in goat ovarian tissues before and after pregnancy

This study performed transcriptome sequencing of ovarian tissues from JG goats at three key reproductive stages-non-pregnant (8 mo old, M8), pregnant (10 mo old, M10), and postpartum (12 mo old, M12). A total of 93 differentially expressed (DE) miRNAs were identified across all libraries, with the M8 vs. M10 group having the largest number (34 upregulated and 47 downregulated; |log₂ fold change| > 1, FDR < 0.05). These stage-specific DE miRNAs were clustered into four groups, with their target genes primarily enriched in signaling pathways such as Wnt, JAK-STAT, PI3K-Akt, VEGF, and steroid biosynthesis, which are important factors influencing ovarian cell activity, hormone secretion, angiogenesis, and embryonic development. Real-time quantitative polymerase chain reaction verification showed that the expression patterns of the 9 selected DE miRNAs were consistent with the sequencing data. Additionally, through the joint analysis of DE miRNAs and mRNAs, a co-expression network associated with ovarian reproductive function changes was constructed, ultimately highlighting 11 key miRNAs. Dual-luciferase reporter assays further confirmed the direct targeting relationships between core miR-432-5p and CPT1B, as well as miR-455-3p and PLXNB1. In summary, this study revealed the dynamic changes in ovarian miRNA expression profiles from pre-pregnancy to postpartum and their potential molecular mechanisms, providing theoretical support and key molecular targets for miRNAs in reproductive regulation, with significant implications for improving reproductive efficiency in livestock.