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

Female under-nutrition during early pregnancy may affect the physiological pattern of the transcriptomic profile in the endometrium. We aimed to determine if restricted diet applied to females during peri-conceptional period, that is, from the onset of the oestrus until day nine of pregnancy, alters transcriptomic profile in the endometrium during the peri-implantation period. The restricted diet gilts were fed forage, in which the dose of proteins and energy had been reduced by 30% compared to normal diet. Microarray analysis revealed that approximately 4% of transcripts, that is 1690 of 43803 probes from The Porcine (V2) Gene Expression Microarray 4 × 44 (Agilent Technologies, Santa Clara, CA, USA) were consistently altered (p ≤ .05) in the endometrium harvested from pigs fed restricted diet. In pigs fed restricted diet out of 1690 genes, 714 genes were upregulated and 976 genes were downregulated versus in pigs fed normal diet. From 1690 genes, 510 (30%) were genes with known biological functions in the KEGG database. The proportions of the differentially expressed transcripts were organized into six major categories and 39 subcategories containing 259 pathways associated with the differentially expressed genes. The largest amount of differentially expressed genes was involved in metabolism category. The most relevant genes were involved in gene ontology (GO) cellular component (CC) term. These findings suggest that females under-nutrition during peri-conceptional period may create changes in endometrial transcriptome during the peri-implantation period creating the potential changes in physiological functions of peri-implantation endometrium.

Expression of 17ß-hydroxysteroid dehydrogenase and the effects of LH, FSH and prolactin on oestrone and 17ß-oestradiol secretion in the endometrium of pigs during early pregnancy and the oestrous cycle.

The endometrium of pregnant and cyclic pigs is a source of oestrone (E1) and 17ß-oestradiol (E2). However, the roles of LH, FSH and prolactin (PRL) as regulators of endometrial steroidogenesis, and the presence of 17ß-hydroxysteroid dehydrogenase (17ß-HSD) in the porcine endometrium, remain unknown. Therefore, in the present study we examined 17ß-HSD expression and the effects of LH, FSH and PRL on E1 and E2 release in vitro in endometrial explants harvested from gravid pigs on Days 10-11 (embryo migration within the uterus), 12-13 (maternal recognition of pregnancy) and 15-16 (beginning of implantation) and compared them with results obtained in non-gravid pigs. The results show that: (1) endometrial 17ß-HSD activity was decreased on Days 15-16 in pregnant and cyclic pigs compared with the preceding days; (2) LH, FSH and PRL increased endometrial E1 secretion on Days 10-11 and 15-16 of pregnancy and on Days 12-13 and 15-16 of the oestrous cycle; and (3) LH, FSH and PRL increased endometrial E2 secretion on Days 15-16 of pregnancy and during the days studied in the oestrous cycle. In conclusion, data suggest that LH, FSH and PRL affect endometrial secretion of estrogens in pigs.

Periconceptional undernutrition affects in utero methyltransferase expression and steroid hormone concentrations in uterine flushings and blood plasma during the peri-implantation period in domestic pigs.

Female undernutrition during early pregnancy may affect the physiological pattern of genomic DNA methylation. We hypothesised that in utero DNA methylation may be impaired in females fed a restrictive diet in early pregnancy. In this study we evaluated whether poor maternal nutritional status, induced by applying a restricted diet during the peri-conceptional period, may influence: (1) the potential for in utero DNA methylation, expressed as changes in the mRNA expression and protein abundance of methyltransferases: DNA methyltransferase 1 (DNMT1) and DNMT3a in the endometrium and the myometrium, (2) the intrauterine microenvironment, measured as oestradiol 17ß (E2) and progesterone (P4) concentrations in uterine flushings and (3) plasma concentration of E2 and P4 during the peri-implantation period. Our results indicate that maternal peri-conceptional undernutrition affects maintenance and de novo DNA methylation in the endometrium, de novo methylation in the myometrium and a results in a decrease in intrauterine E2 concentration during the peri-implantation period. The intrauterine concentration of P4 and plasma concentrations of E2 and P4 did not change. These findings suggest that undernutrition during the earliest period of pregnancy, and perhaps the pre-pregnancy period, may create changes in epigenetic mechanisms in the uterus and intrauterine milieu of E2 during the peri-implantation period.

Peri-conceptional under-nutrition alters the expression of TRIM28 and ZFP57 in the endometrium and embryos during peri-implantation period in domestic pigs.

DNA methylation is maintained by the main elements of methylation complex-tripartite motif containing 28 (TRIM28) and zinc finger protein 57 (ZFP57). Previously, it was found that the activity of TRIM28 and ZFP57 determines the process of DNA methylation and preserves over-expression of genes. We hypothesized that restricted diet applied during peri-conceptional period may induce changes in the expression of methylation complex in porcine endometrium and embryos during the peri-implantation period. The aim of this study was to detect and determine the expression of TRIM28 and ZFP57 in the endometrium and embryos harvested from gilts during the peri-implantation period (days 15-16 of pregnancy) fed restricted (n = 5) or normal (n = 5) diet during peri-conceptional period. In restricted-diet-fed gilts, endometrial expression of TRIM28 and ZFP57 mRNAs was decreased in comparison with normal-diet-fed gilts (p ≤ .01), while the embryonic expression of TRIM28 and ZFP57 mRNAs was increased in restricted-diet-fed gilts (p ≤ .05). The immunofluorescence showed the presence of TRIM28 and ZFP57 in luminal epithelial (LE), glandular epithelial (GE) and stromal cells (ST) of the endometrium as well as in the embryos. Total endometrial and embryonic abundance of TRIM28 and ZFP57 proteins was significantly higher (p ≤ .05) in restricted-diet-fed gilts than in normal-diet-fed gilts. Female under-nutrition during peri-conceptional period affects the expression of two main elements of methylation complex in the endometrium and in embryos during the peri-implantation period and may have the impact on DNA methylation in these tissues.