Differential MicroRNA Expression in Porcine Endometrium Related to Spontaneous Embryo Loss during Early Pregnancy

Abstract

Litter size is an important indicator to measure the production capacity of commercial pigs. Spontaneous embryo loss is an essential factor in determining sow litter size. In early pregnancy, spontaneous embryo loss in porcine is as high as 20–30% during embryo implantation. However, the specific molecular mechanism underlying spontaneous embryo loss at the end of embryo implantation remains unknown. Therefore, we comprehensively used small RNA sequencing technology, bioinformatics analysis, and molecular experiments to determine the microRNA (miRNA) expression profile in the healthy and arresting embryo implantation site of porcine endometrium on day of gestation (DG) 28. A total of 464 miRNAs were identified in arresting endometrium (AE) and healthy endometrium (HE), and 139 differentially expressed miRNAs (DEMs) were screened. We combined the mRNA sequencing dataset from the SRA database to predict the target genes of these miRNAs. A quantitative real-time PCR assay identified the expression levels of miRNAs and mRNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed on differentially expressed target genes of DEMs, mainly enriched in epithelial development and amino acids metabolism-related pathways. We performed fluorescence in situ hybridization (FISH) and the dual-luciferase report gene assay to confirm miRNA and predicted target gene binding. miR-205 may inhibit its expression by combining 3′-untranslated regions (3′ UTR) of tubulointerstitial nephritis antigen-like 1 (TINAGL1). The resulting inhibition of angiogenesis in the maternal endometrium ultimately leads to the formation of arresting embryos during the implantation period. This study provides a reference for the effect of miRNA on the successful implantation of pig embryos in early gestation.

Bioinformatics analysis of a disease-specific lncRNA–miRNA–mRNA regulatory network in recurrent spontaneous abortion (RSA)

“…In RSA patients, there has been evidence of a downregulation in miRNA expression. In endometrial samples from individuals who experienced repeated abortions during early pregnancy, miR-671-5p was similarly found to be down-regulated (Gu, Zang et al 2022). The targets of miR-671 are implicated in the cell cycle, intercellular communication, and cell adhesion pathways, all of which are crucial for the growth and implantation of the embryo (Van Mourik, Macklon et al 2009).…”

Effect of miR-143-3p from Extracellular Vesicles of Porcine Uterine Luminal Fluid on Porcine Trophoblast Cells

“…Embryo survival rate is one of the major factors determining the fertility of sows. During the whole porcine pregnancy process, only approximately 60% of embryos eventually survive, and the remaining 20–30% experience death during the early and middle stages of gestation, which results in a serious waste of embryo resources and limited reproductive performance of sows [ 1 , 2 , 3 ]. Meishan pigs are currently recognized as one of the most productive pigs in the world, with significantly more piglets than the Yorkshire pig at the same ovulation rate [ 4 , 5 ].…”