The effects of estrogen and progesterone on prostaglandins and integrin beta 3 (beta3) subunit expression in primary cultures of bovine endometrial cells

miR-1246 is implicated as a possible candidate for endometrium remodelling facilitating implantation in buffalo (Bubalus bubalis)

BACKGROUND

The microRNAs (miRs) secreted by the trophectoderm (TE) cells have recently been implicated in the conceptus-endometrial cross talk during implantation and placentation. These miRs modulate various cellular processes during conception and throughout the pregnancy by regulating the gene expression in the foetal and maternal tissues.

OBJECTIVES

This study was undertaken to elucidate the function of TE secreted miRNAs in the maternal-foetal cross-talk during implantation/placentation in buffalo.

METHODS

The in vitro produced blastocysts were cultured on a cumulus feeder layer for 21 days. The relative expression profiles of a selected panel of miRs was generated using the spent media collected on Days 0, 7, 12, 16, and 21. A custom-designed mirVana™ miRNA mimic was used to transfect the endometrial epithelial cells (EECs) in order to determine the role of miRNA exhibiting highest expression on Days 21 and 21.

RESULTS

The expression of miR-1246 (p < 0.001) and let-7b (p < 0.01) was found to be significantly higher on Day 21 of TE culture in comparison to the control (Day 0). This elevated expression indicated the involvement of these miRs in the maternal-foetal cross-talk. Interestingly, after the transfection of EECs with miRNA mimic for miR-1246 (a novel molecule vis-à-vis implantation), the expression of beta-catenin and mucin1 in these cells was found to be significantly (p < 0.05) downregulated vis-à-vis the control, that is, the IFN-τ primed EECs (before transfection).

CONCLUSIONS

The TE secreted miR-1246 appeared to lower the expression of the endometrial receptivity genes (mucin1 and beta-catenin) which apparently assists the endometrium in preparing for placentation.

Exosomes derived from placental trophoblast cells regulate endometrial epithelial receptivity in dairy cows during pregnancy

Inadequate fetomaternal interactions could directly lead to pregnancy failure in dairy cows. Exosomes are widely involved in endometrial matrix remodeling, immune function changes, placental development, and other processes of embryo implantation and pregnancy in dairy cows. However, the role of exosomes derived from placental trophoblast cells in regulating the receptivity of endometrial cells and facilitating fetomaternal interaction remains unclear. In this study, bovine trophoblast cells (BTCs) were obtained from bovine placenta and immortalized by transfection with telomerase reverse transcriptase (TERT). Immortalized BTCs still possess the basic and key properties of primary BTCs without exhibiting any neoplastic transformation signs. Subsequently, the effect of trophoblast-derived exosomes (TDEs) on endometrial receptivity in endometrial epithelial cells (EECs) was determined, and the mechanism whereby TDEs and their proteins participate in the fetomaternal interaction during bovine pregnancy were explored. EECs were co-cultured with the exosomes derived from BTCs treated with progesterone (P4). Such treatment enhanced the expression of the endometrial receptivity factors, integrin αv, β3, Wnt7a, and MUC1 by changing the extracellular environment, metabolism, and redox balance in EECs via proteome alignment, compared with no treatment according to the DIA quantitation analysis. Our study demonstrated that trophoblast-derived exosome proteins are one of the most critical elements in fetomaternal interaction, and their changes may act as a key signal in altering endometrial receptivity and provide a potential target for improving fertility.

New Insights into the Activities of D-Chiro-Inositol: A Narrative Review

D-chiro-inositol (DCI) is a natural compound detectable in cell membranes, which is highly conserved as a biological signaling molecule. In mammals, its function is primarily characterized in the intracellular transduction cascade of insulin. In particular, insulin signal promotes the release of pivotal DCI-containing molecules. In fact, impaired release of DCI is a common feature of insulin-resistant tissues, and insulin-sensitizing pharmaceuticals induce higher concentrations of free DCI. Moreover, it also plays important roles in several other processes. DCI is involved in the regulation of steroidogenesis, due to its regulatory effects on steroidogenic enzymes, including 17α-hydroxylase, 3β-hydroxysteroid dehydrogenase, and aromatase. Such regulation of various enzymes indicates a mechanism by which the body regulates different processes via a single molecule, depending on its concentration. DCI also reduces the expression of integrin β3, which is an adhesion molecule involved in embryo implantation and cellular phenomena such as survival, stemness, and invasiveness. In addition, DCI seems to have important anti-inflammatory activities, like its 3-O-methyl-ether, called pinitol. In vitro evidence demonstrates that treatment with both compounds induces a reduction in pro-inflammatory factors—such as Nf-κB—and cytokines—such as TNF-α. DCI then plays important roles in several fundamental processes in physiology. Therefore, research on such molecule is of primary importance.

Expression of glucocorticoid receptor α and its regulation in the bovine endometrium: possible role in cyclic prostaglandin F2α production

Cortisol (Cr), the most important glucocorticoid (GC), is well known to suppress uterine prostaglandin F2α (PGF) production. However, the details of the regulatory mechanisms controlling the cyclic changes in endometrial PGF production remain unclear. Here we investigated the expression of the GC receptor (GC-Rα), the actions of cortisol throughout the estrous cycle and the regulatory mechanism of GC-Rα in the bovine endometrium. The levels of GC-Rα protein were greater at the mid-luteal stage (Days 8-12) than at the other stages. Cr more strongly suppressed PGF production at the mid-luteal stage than at the follicular stage. GC-Rα expression was increased by progesterone (P4) but decreased by estradiol-17β (E2) in cultured endometrial stromal cells. The overall results suggest that ovarian steroid hormones control the cyclic changes in endometrial PGF production by regulating GC-Rα expression in bovine endometrial stromal cells.

The serotonergic system: its role in pathogenesis and early developmental treatment of autism

Autism is a severe childhood disorder already presenting in the first 3 years of life and, therefore, strongly correlated with neurodevelopmental alterations in prenatal, as well as postnatal period. Neurotransmitters hold a pivotal role in development by providing the stimulation needed for synapses and neuronal networks to be formed during the critical period of neuroplasticity. Aberrations of the serotonergic system modify key processes in the developing brain and are strongly implicated in the pathophysiology of developmental disorders. Evidence for the role of serotonin in autism emerges from neuropathological, imaging and genetic studies. Due to its developmental arrest, autism requires early intervention that would, among others, target the disrupted serotonergic system and utilize brain plasticity to elicit clinically important brain changes in children.

Expression and function of Toll-like receptor 4 in the endometrial cells of the uterus

Prostaglandins have a central role in many endocrine functions in mammals, including regulation of the life span of the corpus luteum by prostaglandin F(2alpha) (PGF) and prostaglandin E2 (PGE), which are secreted by the uterine endometrium. However, the uterus is readily infected with bacteria such as Escherichia coli, which disrupt luteolysis. Immune cells detect E. coli by Toll-like receptor 4 (TLR4) binding its pathogenic ligand, lipopolysaccharide (LPS), although signaling requires accessory molecules such as CD14. The objective of this study was to determine the effect of E. coli or LPS on the function of bovine endometrial cells, and whether purified populations of epithelial and stromal cells express the molecules involved in LPS recognition. In addition, because the female sex hormones estradiol and progesterone modify the risk of uterine infection, their effect on the LPS response was investigated. Endometrial explants produced prostaglandins in response to LPS, with an increased ratio of PGE to PGF. Addition of LPS or E. coli to stromal and epithelial cells stimulated production of PGE and PGF and increased their cyclooxygenase 2 mRNA expression. The production of prostaglandins was abrogated by an LPS antagonist. In addition, estradiol and progesterone inhibited the production of PGE and PGF in response to LPS, indicating a role for steroid hormones in the response to bacterial infection. For the first time, Toll-like receptor 4 mRNA and CD14 mRNA and protein were detected in bovine endometrial stromal and epithelial cells by RT-PCR and flow cytometry. In conclusion, epithelial and stromal cells detect and respond to bacteria, which modulate their endocrine function.

Variation in ITGB3 has sex-specific associations with plasma lipoprotein(a) and whole blood serotonin levels in a population-based sample

A recent genome-scan identified the Leu33Pro polymorphism in the beta3 integrin (ITGB3) gene as a quantitative trait locus for whole blood serotonin level in a large Hutterite pedigree. Because both the Leu33Pro polymorphism and the serotonin system have been implicated in cardiovascular disease (CVD) risk and treatment response, we studied additional variation in ITGB3 and its relationship to intermediate phenotypes associated with CVD in the same population. We examined associations between 15 single nucleotide polymorphisms (SNPs) across ITGB3 and five CVD-related traits in the Hutterites: plasma levels of high density lipoprotein-cholesterol (HDL-c), triglycerides (TG), low density lipoprotein-cholesterol (LDL-c), and lipoprotein(a) [Lp(a)] and blood pressure or hypertension. Seven of these SNPs in ITGB3 were associated with whole blood serotonin. Among the intermediate CVD-related phenotypes, only Lp(a) was associated with multiple ITGB3 SNPs, five of which were also associated with serotonin. A sex-stratified analysis revealed that the association between ITGB3 and Lp(a) is present only in females, whereas the association between ITGB3 and serotonin is concentrated in males. Our results suggest that variation in ITGB3 in addition to Leu33Pro could contribute to susceptibility to CVD and serotonin in a sex-specific manner.

Sex-specific genetic architecture of whole blood serotonin levels

Recently, a quantitative-trait locus (QTL) for whole blood serotonin level was identified in a genomewide linkage and association study in a founder population. Because serotonin level is a sexually dimorphic trait, in the present study, we evaluated the sex-specific genetic architecture of whole blood serotonin level in the same population. Here, we use an extended homozygosity-by-descent linkage method that is suitable for large complex pedigrees. Although both males and females have high broad heritability (H2=0.99), females have a higher additive component (h2=0.63 in females; h2=0.27 in males). Furthermore, the serotonin QTL on 17q that was identified previously in this population, integrin beta 3 (ITGB3), and a novel locus on 2q influence serotonin levels only in males, whereas linkage to a region on chromosome 6q is specific to females. Both sexes contribute to linkage signals on 12q and 16p. There were, overall, more associations meeting criteria for suggestive significance in males than in females, including those of ITGB3 and the serotonin transporter gene (5HTT). This analysis is consistent with heritable sexual dimorphism in whole blood serotonin levels resulting from the effects of a combination of sex-specific and sex-independent loci.

The effects of estrogen, its antagonist ICI 182, 780, and interferon-tau on the expression of estrogen receptors and integrin alphaV beta 3 on cycle day 16 in bovine endometrium

We have shown previously that downregulation of intercaruncular stromal integrin alphavbeta3 in bovine endometrium on day 16 of the estrous cycle coincided with the antibody recognition of estrogen receptors (ER) in the luminal epithelium. In pregnancy, these changes were not observed. Our hypothesis was that on day 16 of the estrous cycle, estrogen from the dominant follicle causes a reduction in integrin alphavbeta3 and affects ERalpha in the luminal epithelium. The pregnancy recognition protein, interferon-tau (IFN-tau), may prevent downregulation of integrin alphavbeta3 and suppress ERalpha expression in the luminal epithelium. On days 14 to 16, heifers received uterine infusions of the anti-estrogen ICI 182, 780, estradiol 17beta, IFN-tau or the saline control. On day 16, reproductive tracts were collected for analysis of integrin alphavbeta3 and ERalpha. Estrogen receptor alpha immunoreactivity was largely restricted to the luminal epithelium in control animals. Using anti-ERalpha recognizing the amino terminus, estrogen-treated animals showed reactivity in the stroma, shallow and deep glands and myometrium as is typical of estrus, whereas ICI 182, 870 treated heifers showed little or no reactivity. In contrast, carboxyl terminus-directed antibodies showed a widespread distribution of ERalpha with reactivity detected in the uterine epithelium, stroma and myometrium of both estrogen and ICI 182, 780 treated animals. Heifers treated with IFN-tau had low ERalpha reactivity overall. Control and IFN-tau treated heifers had lower intercaruncular stromal expression of integrin alphavbeta3 in comparison to estrogen and ICI 182, 780 treatments. Overall, the results suggest that on day 16 of the estrous cycle, estrogen effects on integrin alphavbeta3 are indirect and do not directly involve ERalpha in the luminal epithelium. During pregnancy, interferon-tau may block ERalpha in the luminal epithelium but likely does not rescue integrin alphavbeta3 expression.