Abstract
MicroRNAs (miRNAs) constitute a large family of noncoding RNAs, approximately 22 nucleotides long, which function as guide molecules in RNA silencing. Targeting most protein-coding transcripts, miRNAs are involved in nearly all developmental and pathophysiological processes in animals. To date, the regulatory roles of miRNAs in reproduction, such as fertilization, embryo development, implantation, and placenta formation, among others, have been demonstrated in numerous mammalian species, including domestic livestock such as pigs. Over the past years, it appeared that understanding the functions of miRNAs in mammalian reproduction can substantially improve our understanding of the biological challenges of successful reproductive performance. This review describes the current knowledge on miRNAs, specifically in relation to the peri-implantation period when the majority of embryonic mortality occurs in pigs. To present a broader picture of crucial peri-implantation events, we focus on the role of miRNA-processing machinery and miRNA–mRNA infarctions during the maternal recognition of pregnancy, leading to maintenance of the corpus luteum function and further embryo implantation. Furthermore, we summarize the current knowledge on cell-to-cell communication involving extracellular vesicles at the embryo–maternal interface in pigs. Finally, we discuss the potential of circulating miRNAs to serve as indicators of ongoing embryo–maternal crosstalk.
Highlights
Pregnancy in domestic animals, such as pigs, begins with the period of development of the embryo(s) in the oviduct to reach the blastocyst stage in the uterus
Other studies performed on the bovine corpus luteum (CL) identified 15 miRNAs differentially expressed on day 18 of pregnancy vs. the corresponding day of the estrous cycle, while among predicted targets of these miRNAs, genes involved in immune-related events and apoptosis were found [72]
MiRNAs can be recognized as powerful gene expression regulators during the peri-implantation period in livestock, such as pigs
Summary
Pregnancy in domestic animals, such as pigs, begins with the period of development of the embryo(s) in the oviduct to reach the blastocyst stage in the uterus. Reciprocal communication between the preimplantation conceptus results in maintaining P4 production by the ovaries and sets up the environment for successful embryonic development and implantation. Establishing firm connections between the endometrium and the embryo requires a specific mutual dialogue achieved through the secretion of steroid hormones as well as a number of different agents, such as growth factors, prostanoids, and cytokines [2,3]. We summarize recent progress in miRNA-mediated regulations of the peri-implantation period in pigs and highlight the significance of miRNAs in different aspects of successful pregnancy outcomes. We discuss an intriguing characteristic of miRNAs—their presence in circulation—and provide a set of conclusive remarks to guide future studies
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
