Microarray Analysis of Gene Expression in the Uterine Endometrium during the Implantation Period in Pigs

Abstract

During embryo implantation in pigs, the uterine endometrium undergoes dramatic morphological and functional changes accompanied with dynamic gene expression. Since the greatest amount of embryonic losses occur during this period, it is essential to understand the expression and function of genes in the uterine endometrium. Although many reports have studied gene expression in the uterine endometrium during the estrous cycle and pregnancy, the pattern of global gene expression in the uterine endometrium in response to the presence of a conceptus (embryo/fetus and associated extraembryonic membranes) has not been completely determined. To better understand the expression of pregnancy-specific genes in the endometrium during the implantation period, we analyzed global gene expression in the endometrium on day (D) 12 and D15 of pregnancy and the estrous cycle using a microarray technique in order to identify differentially expressed endometrial genes between D12 of pregnancy and D12 of the estrous cycle and between D15 of pregnancy and D15 of the estrous cycle. Results showed that the global pattern of gene expression varied with pregnancy status. Among 23,937 genes analyzed, 99 and 213 up-regulated genes and 92 and 231 down-regulated genes were identified as differentially expressed genes (DEGs) in the uterine endometrium on D12 and D15 of pregnancy compared to D12 and D15 of the estrous cycle, respectively. Functional annotation clustering analysis showed that those DEGs included genes involved in immunity, steroidogenesis, cell-to-cell interaction, and tissue remodeling. These findings suggest that the implantation process regulates differential endometrial gene expression to support the establishment of pregnancy in pigs. Further analysis of the genes identified in this study will provide insight into the cellular and molecular bases of the implantation process in pigs.

Peri‐conceptional under‐nutrition alters transcriptomic profile in the endometrium during the peri‐implantation period—The study in domestic pigs

“…In restricted‐diet‐fed gilts, when compared to a normal‐diet‐fed gilts, out of 1690 genes, 976 genes were downregulated and 714 genes were upregulated. It is worth to note that in general, during the peri‐implantation period, endometrial genes were mostly downregulated when compared to the endometrium of non‐gravid pigs (Franczak et al., ; Kim et al., ; Østrup, Bauersachs, Blum, Wolf, & Hyttel, ). Observed in our study, decreased activity of a majority of genes in gravid endometrium harvested from a restricted‐diet‐fed gilts may contribute to deregulation of crucial processes occurred in the tissue that affects the proper intrauterine milieu.…”

Analyses of Long Non-Coding RNA and mRNA profiling using RNA sequencing during the pre-implantation phases in pig endometrium

“…A stable adhesion between conceptus and endometrium requires reduction in mucin-1 on the apical surface of epithelium Furthermore, growth factors, cytokines and its receptors are all involved in embryo-maternal interactions 9 10 . In response to these factors, the uterine endometrial undergoes dramatic morphological and functional changes to be more easily receptive to the conceptus development 11 . Thus, to increase the rate of successful implantation, it is essential to understand the mechanism of the genetic regulation of endometrial changes.…”

mRNA/lncRNA expression patterns and the function of fibrinogen‐like protein 2 in Meishan pig endometrium during the preimplantation phases

“…In addition, a recent study by Chen et al () revealed that the “immune response” is highly overrepresented for genes specifically upregulated in endometrial attachment sites. However, many previous studies have also demonstrated that the biological function of immune cells is decreased in the endometrium on Day 12 of pregnancy, and during the implantation period in pigs, maternal immune suppression contributes to the establishment of pregnancy (Bischof, Lee, Lee, & Meeusen, ; Kim et al, ). “ECM‐receptor interaction” was the common pathway among these three comparison groups.…”