Differential Gene Expression in Uterine Endometrium During Implantation in Pigs1

Abstract

Embryonic mortality during the implantation period strongly affects litter size in pigs. To analyze the differentially expressed genes (DEGs) in the endometrium during implantation and further to identify candidate genes for litter size, tissues of endometrial attachment sites and intersites were collected from nine pregnant sows on Days 13, 18, and 24 of pregnancy. Endometrium tissue was also collected from another three nonpregnant sows. Samples were hybridized to the porcine Agilent GeneChip microarray. The analysis of gene expression patterns over the implantation period revealed 858 DEGs at endometrial attachment sites. Comparisons of the gene files of attachment sites and intersites revealed 12, 51, and 89 DEGs on Days 13, 18, and 24 of pregnancy, respectively. Annotated function was used to identify overrepresented genetic processes, and several biological processes were considered as the most enriched. Genes related to vascular development, proteolysis, RNA metabolism and translation, protein modification, immune response, and hormone-related are discussed in detail. Then we combined microarray technology and linkage analysis to select powerful candidate genes for quantitative trait loci affecting pig litter size. Eighty-seven DEGs were located in quantitative trait loci related to litter size, that is, total number born and number born alive. Those candidate genes were thought to affect litter size by influencing embryonic implantation. Furthermore, single nucleotide polymorphism of VEGFA was shown to be associated with litter size in pigs. This study identified candidate genes for litter size that were related to embryonic implantation and could be a resource for target studies of genetic markers for litter size in pigs.

Implantation and Establishment of Pregnancy in the Pig

“…5 ). Changes in endometrial transcriptome during early stages of conceptus attachment to uterine LE are just beginning to widen our understanding of the critical factors involved with establishment and maintenance of pregnancy in the pig (Samborski et al 2013 ;Chen et al 2015 ;Kiewisz et al 2014 ). The emergence of microRNAs as posttranscriptional players in regulating gene function has added a new area of investigation to enhance understanding of conceptus-endometrial interactions (Krawczynski et al 2015 ).…”

Proteomes of the Female Genital Tract During the Oestrous Cycle

“…The regulation of the uterine transcriptome during the preimplantation phase has been intensively studied in several species (sheep (73), bovine (74,75), horse (21,76), and pig (77)(78)(79)) and the proteome of uterine fluid during the early stages of pregnancy was analyzed in cattle and sheep (80 -82). Several proteins we found more abundant in the uterine luminal fluid during the luteal phase were also described as uterine markers of early pregnancy with an increased production in the presence of an embryo.…”

Endometrial gene expression profile of pregnant sows with extreme phenotypes for reproductive efficiency

“…Several DEGs found in our samples have been extensively discussed by many authors before373839404142, and their involvement in the establishment of pregnancy and in the physiological, molecular and structural changes that take place in the uterine tissue to promote embryo implantation have been demonstrated in pigs and other mammals . Their involvement in many stages of embryonic development postulate them as key factors for deciphering the mechanisms involved in the regulation of litter size in our study population.…”