Effects of aberrant estrogen on the endometrial transcriptional profile in pigs

Estradiol-17β-Induced Changes in the Porcine Endometrial Transcriptome In Vivo

Estradiol-17β (E2) is a key hormone regulating reproductive functions in females. In pigs, E2, as the main conceptus signal, initiates processes resulting in prolonged corpus luteum function, embryo development, and implantation. During early pregnancy the endometrium undergoes morphological and physiological transitions that are tightly related to transcriptome changes. Recently, however, the importance of E2 as a primary conceptus signal in the pig has been questionable. Thus, the aim of the present study was to determine the effects of E2 on the porcine endometrial transcriptome in vivo and to compare these effects with transcriptome profiles on day 12 of pregnancy. Microarray analysis revealed differentially expressed genes (DEGs) in response to E2 with overrepresented functional terms related to secretive functions, extracellular vesicles, cell adhesion, proliferation and differentiation, tissue rearrangements, immune response, lipid metabolism, and many others. Numerous common DEGs and processes for the endometrium on day 12 of pregnancy and E2-treated endometrium were identified. In summary, the present study is the first evidence for the effect of E2 on transcriptome profiles in porcine endometrium in vivo in the period corresponding to the maternal recognition of pregnancy. The presented results provide a valuable resource for further targeted studies considering genes and pathways regulated by conceptus-derived estrogens and their role in pregnancy establishment.

Effects of Early Intervention with Antibiotics and Maternal Fecal Microbiota on Transcriptomic Profiling Ileal Mucusa in Neonatal Pigs

This study aimed to investigate the effects of early intervention with antibiotics and maternal fecal microbiota on ileal morphology and barrier function, and transcriptomic profiling in neonatal piglets. Piglets in the amoxicillin (AM), fecal microbiota transplantation (FMT), and control (CO) groups were orally administrated with amoxicillin solution (6.94 mg/mL), maternal fecal microbiota suspension [>109 colony forming unit (CFU)/mL], and physiological saline, respectively. Compared with the CO group, early intervention with AM or FMT significantly decreased ileal crypt depth on day 7 and altered gene expression profiles in ileum on days 7 and 21, and especially promoted the expression of chemokines (CCL5, CXCL9, and CXCL11) involved in the toll-like receptor signaling pathway on day 21. FMT changed major immune activities from B cell immunity on day 7 to T cell immunity on day 21 in the ileum. On the other hand, both AM and FMT predominantly downregulated the gene expression of toll-like receptor 4 (TLR4). In summary, both early interventions modulated intestinal barrier function and immune system in the ileum with a low impact on ileal morphology and development.

Exposure of pregnant sows to low doses of estradiol-17β impacts on the transcriptome of the endometrium and the female preimplantation embryos†

Maternal exposure to estrogens can induce long-term adverse effects in the offspring. The epigenetic programming may start as early as the period of preimplantation development. We analyzed the effects of gestational estradiol-17β (E2) exposure with two distinct low doses, corresponding to the acceptable daily intake "ADI" and close to the no-observed-effect level "NOEL", and a high dose (0.05, 10, and 1000 μg E2/kg body weight daily, respectively). The E2 doses were orally applied to sows from insemination until sampling at day 10 of pregnancy and compared to carrier-treated controls leading to a significant increase in E2 in plasma, bile and selected somatic tissues including the endometrium in the high-dose group. Conjugated and unconjugated E2 metabolites were as well elevated in the NOEL group. Although RNA-sequencing revealed a dose-dependent effect of 14, 17, and 27 differentially expressed genes (DEG) in the endometrium, single embryos were much more affected with 982 DEG in female blastocysts of the high-dose group, while none were present in the corresponding male embryos. Moreover, the NOEL treatment caused 62 and 3 DEG in female and male embryos, respectively. Thus, we detected a perturbed sex-specific gene expression profile leading to a leveling of the transcriptome profiles of female and male embryos. The preimplantation period therefore demonstrates a vulnerable time window for estrogen exposure, potentially constituting the cause for lasting consequences. The molecular fingerprint of low-dose estrogen exposure on developing embryos warrants a careful revisit of effect level thresholds.

The effect of interleukin-1β, interleukin-6, and tumor necrosis factor-α on estradiol-17β release in the myometrium: the in vitro study on the pig model

Estradiol-17β (E2) is a potent regulator of early pregnancy and the estrous cycle in pigs. Production of E2 occurs in the porcine myometrium, but the factors involved in its regulation are unknown. In this in vitro study, it was investigated whether interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α affect the release of E2 from the porcine myometrium on Days 10 to 11, 12 to 13, and 15 to 16 of pregnancy and the estrous cycle. The expression of the cytochrome P450 family 19 (CYP19) gene and the presence of the aromatase cytochrome P450 protein in the myometrium confirmed the ability of the tissue to produce E2. In gravid pigs, the expression of IL1RI mRNA and IL6R mRNA was markedly increased on Days 15 to 16 of gestation, whereas TNFRI mRNA was increased on Days 10 to 11 of gestation. In cyclic pigs, the expression of myometrial IL1RI mRNA did not differ among the studied days, although the expression of IL6R and TNFRI mRNAs was increased on Days 15 to 16. In gravid pigs, IL-1β, IL-6, and TNF-α increased myometrial E2 secretion on Days 15 to 16 but did not affect E2 release on Days 10 to 11 and 12 to 13 of pregnancy. In cyclic pigs, IL-1β, IL-6, and TNF-α did not increase myometrial E2 release. In conclusion, IL-1β, IL-6, and TNF-α affected myometrial E2 release in a manner that is dependent on the physiologic status of the female. The porcine myometrium expresses IL1RI, IL6R, and TNFRI genes and is the target tissue for IL-1β, IL-6, and TNF-α. In gravid pigs, IL-1β, IL-6, and TNF-α may increase myometrial release of E2 in vitro specifically on Days 15 to 16 of pregnancy. These findings may be of interest to researchers using pigs as an animal model for fetal programming.

Transcriptomic analysis of the porcine endometrium during early pregnancy and the estrous cycle

The goal of this study was to describe the alterations in the transcriptome of the endometrium in pigs during the beginning of implantation (days 15-16 of pregnancy) compared to cyclic pigs during the onset of luteolysis (days 15-16 of the estrous cycle). The global expression of genes in porcine gravid and non-gravid endometria was investigated using the Porcine (V2) Two-color gene expression microarray, 4 × 44 (Agilent, USA). Analysis of the microarray data showed that, of 589 accurately annotated genes, the expression of 266 genes was up-regulated and expression of 323 was down-regulated in the endometrium harvested during early pregnancy compared with the endometrium during the estrous cycle. In pregnant pigs, genes with the most significantly altered expression were involved in the following biological processes: the metabolic process, cellular process, cell communication, immune system process, developmental process, cell adhesion, antigen processing and presentation, antigen processing and presentation of peptide or polysaccharide antigen via major histocompatibility complex (MHC) class II, immune response, and the polysaccharide metabolic process. In the pregnant endometrium, cell adhesion molecules and steroid hormone biosynthesis pathways were the most significantly enriched biological pathways. Analysis of the interaction network among selected genes showed that androgen receptor (AR) encoding genes interact with genes involved in important processes occurring during early pregnancy. The bioinformatic analysis revealed information about the meaning of differentially expressed genes. The data provided new insight into the dynamic changes of the endometrial gene expression profile during days 15-16 of pregnancy.