The effect of dexamethasone on uterine receptivity, mediated by the ERK1/2-mTOR pathway, and the implantation window: An experimental study.

Background: The role of glucocorticoids in implantation has been demonstrated. Objective: This study aimed to evaluate the effect of dexamethasone on endometrial receptivity. Materials and Methods: In this experimental study, 40 BALB/c female mice aged eight wk old weighing approximately 25.0 ± 1.4 gr were used. The mice were divided into four groups (n = 10/each) of control, dexamethasone (100 µg/kg, intraperitoneal injection), mammalian target of rapamycin (mTOR) inhibitor (PP242) (30 mg/kg, intraperitoneal injection), and dexamethasone and PP242. The endometrial epithelium of the mouse was separated to measure messenger RNA expression of heart and neural crest derivatives-expressed protein 2 (HAND2), Msh homeobox 1 (Msx-1), heparin binding epidermal growth factor (HB-EGF), microRNA (miRNA) Let-7a, miRNA-145 and miRNA-451, using real-time polymerase chain reaction. Also, protein expression of mammalian mTOR and eukaryotic translation initiation factor 4E-binding protein1 (4E-BP1) was measured using western blot. Results: The results revealed that the expression of Msx-1, HAND2, HB-EGF, miRNA-451, and miRNA-Let-7a was significantly decreased in the endometrium in the dexamethasone group compared to the control, while the expression of miRNA-145 in the endometrium was up-regulated. Additionally, the administration of PP242, known as an inhibitor of mTOR, was associated with significantly reduced expression of Msx-1, HAND2, HB-EGF, miRNA-451, and miRNA-Let-7a, while PP242 induced messenger RNA expression of miRNA-145. Conclusion: It appears that dexamethasone can diminish uterine receptivity during the implantation period, at least to some extent, through the alteration of particular genes that impact endometrial receptivity. Furthermore, the mTOR pathway seemingly showed an essential role in endometrial receptivity.

miR223-3p, HAND2, and LIF expression regulated by calcitonin in the ERK1/2-mTOR pathway during the implantation window in the endometrium of mice.

PROBLEM: Approximately one-third of infertility cases are related to the female partner, and implantation failure is the primary reason for female infertility. The current research was established to assess the impact of calcitonin on endometrial receptivity. METHODS OF STUDY: 64 female BALB/c mice were assigned to 2 groups as follows: mice with regular ovarian cycle and mice with stimulated ovarian cycle. The two groups were further divided into four subgroups as follows: control (Ctrl), calcitonin (CT), pp242, and CT + pp242 groups. Calcitonin and pp242 were injected on days 3, 4, and 5 of pregnancy. On day 5 of gestation, all of the animals were sacrificed, and their uterine was removed for the morphological analysis, as well as the expression assessment genes and proteins. RESULTS: The results demonstrated that ovarian stimulation increased the rate of phosphorylation of ERK1/2 and mTOR proteins, and resulted in the upregulation of miR-223-3p. The administration of calcitonin also elevated the expression levels of LIF and HAND2 gene in both regular ovarian and ovarian-stimulated cycles. In ovarian-stimulated groups, the administration of calcitonin led to a decrease in the expression of miR-223-3p. Calcitonin administration also markedly increased the phosphorylation of 4EBP1 and ERK1/2 in the regular ovarian cycle. CONCLUSION: It seems that calcitonin is capable of enhancing the endometrial receptivity of the uterine, thereby the overexpression of HAND2 and LIF and downregulation of miR-223-3p through the ERK1/2-mTOR signaling pathway.

The effect of fludrocortisone on the uterine receptivity partially mediated by ERK1/2-mTOR pathway.

Implantation of embryos needs endometrial receptivity. Mineralocorticoids is one of the causes influencing the implantation window. This study targeted to evaluation fludrocortisone different properties on endometrial receptivity. The objective of this study was to assess whether treatment with fludrocortisone could impact the expression of diverse genes and proteins that are involved in uterine receptivity in mice. In this study, 40 female adult BALB/c mice were used. The samples were allocated to four groups of ten. Control group (C) received: vehicle; fludrocortisone group (FCA): received 1.5 mg/kg fludrocortisone; PP242 group (PP242): received 30 mg/kg PP242; fludrocortisone+PP242 group (FCA+PP242): received fludrocortisone and PP242. Mice were killed on window implantation day after mating and confirmed pregnancy. The endometrial epithelium of mouse was collected to assess mRNA expression of leukemia inhibitory factor (LIF), mucin-1 (MUC1), heparin-binding epidermal growth factor (HB-EGF), (Msx.1), miRNA Let-7a, and miRNA 223-3p as well as protein expression of extracellular signal-regulated kinase 1/2 (ERK1/2), mammalian target of rapamycin (mTOR), and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) in the uterine using real-time PCR and western blot, respectively. In comparison with the control group, fludrocortisone administration upregulated the expression of LIF, HB-EGF, Msx.1, miRNA Let-7a, ERK1/2, and mTOR in the epithelial endometrium. The PP242-treated group demonstrated a significant rise in the expression of MUC1, miRNA 223-3p and a remarkable decline in ERK1/2 and p-4E-BP1 levels in comparison with the control group. Combination therapy of (FCA+PP242) resulted in a remarkable rise in LIF, Msx-1, HB-EGF, ERK1/2, and mTOR levels, in comparison with the PP242 group. Furthermore, combination therapy of (FCA+PP242) downregulated the expression of MUC1 in comparison with the PP242-treated group. According to the results, fludrocortisone affected uterine receptivity possibly by means of modulating the expression of genes involved in the uterine receptivity and activation of the ERK1/2-mTOR pathway.

Administration of dexamethasone disrupts endometrial receptivity by alteration of expression of miRNA 223, 200a, LIF, Muc1, SGK1, and ENaC via the ERK1/2-mTOR pathway.

Successful implantation of embryos requires endometrial receptivity. Glucocorticoids are one of the factors influencing the implantation window. In this study, 40 female BALB/c mice were used to study the impacts of dexamethasone administration on endometrial receptivity markers during implantation window. The mice mated and were randomly divided into four groups: control (vehicle), dexamethasone (100 µg/kg, IP), PP242 (30 mg/kg, IP), and dexamethasone + PP242 (Dex + PP242). On the Day 4th and 5th of gestation, mice received their respective treatments and were killed on the 5th day. To assess the expression of Muc1, leukemia inflammatory inhibitor (LIF), serum/glucocorticoid-inducible kinase 1 (SGK1), epithelial Na+ channel (ENaC), miRNA 200a, and miRNA 223-3p in the endometrium real-time polymerase chain reaction was performed. Furthermore, using Western blot analysis protein expressions of extracellular signal-regulated kinase 1/2 (ERK1/2), mammalian target of rapamycin (mTOR), and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) were evaluated. Periodic Acid-Schiff staining was used to examine the histomorphological changes of the uterus. According to the results dexamethasone declined the expression of LIF, whereas upregulated expression of Muc1, SGK1, ENaC mRNA, miRNA 200a, and miRNA 223-3p in the endometrium. In addition, PP242, an mTOR inhibitor, induced mRNA expression of Muc1, miRNA200a, and miRNa223-3p whereas it declined the expression of LIF. Moreover, activity of the ERK1/2-mTOR pathway in the endometrial cells was deterred by dexamethasone and PP242. Nonstop epithelium proliferation and elevated surface glycoproteins layer on epithelium of dexamethasone and/or PP242-received groups were divulged through histochemical analysis. According to the above mentioned results, uterine receptivity during implantation period was declined by dexamethasone, at least in part, through modulation of involved genes in endometrial receptivity and inhibition of the ERK1/2-mTOR pathway.

Calcitonin administration improves endometrial receptivity via regulation of LIF, Muc-1 and microRNA Let-7a in mice.

Calcitonin (CT) is one of the factors affecting the embryo implantation, but its effects on the implantation window have not been fully investigated. The current study investigated the effects of CT on the endometrium receptivity by morphological study and evaluation of leukemia inhibitory factor (LIF), mucin 1 (Muc-1), and microRNA (miRNA) Let-7a in the ovarian stimulation and the normal ovarian cycle. Then the mechanism of the CT effects through the mammalian target of rapamycin (mTOR) signaling pathway was studied by using PP242. A total of 64 BALB/c mice were divided into the normal ovarian cycle and ovarian stimulation groups. Each group consisted of four subgroups: control, calcitonin, PP242, and calcitonin+PP242. CT and PP242 were injected on the fourth of pregnancy into the mice and 24 hr later all the mice were killed. The uterine tissue samples were used for morphological analysis, and endometrial cells were mechanically isolated for evaluation of gene and protein expression. The results showed that ovarian stimulation induced mTOR phosphorylation as well as increased expression of the Let-7a miRNA. In addition, CT injection increased the expression of LIF and miRNA Let-7a in ovarian stimulation similar to that in normal ovarian cycles. However, injection of PP242 reduced expression of miRNA Let-7a and increased Muc-1 expression in ovarian stimulation group. In conclusion, the administration of CT improved endometrial receptivity in mice. This phenomenon occurred by upregulation of LIF, miRNA Let-7a and downregulation of Muc-1 via mTOR signaling pathway.

Upregulation of HB-EGF, Msx.1, and miRNA Let-7a by administration of calcitonin through mTOR and ERK1/2 pathways during a window of implantation in mice.

BACKGROUND: Successful implantation of embryos requires endometrial receptivity. Calcitonin is one of the factors influencing the implantation window. This study aimed to evaluate calcitonin effects on endometrial receptivity. To this end, the effects of calcitonin on the implantation window in the ovarian stimulation and the normal ovarian cycle were investigated by the morphological study of the endometrium as well as the expression of MSX.1, HB-EGF, and micro-RNA (miRNA) Let-7a; then the mechanisms of calcitonin effects were studied through the mammalian target of rapamycin (mTOR) and extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathways. MATERIALS AND METHODS: A total of 64 Bulb/c mice were divided into two groups: Normal ovarian cycle and ovarian stimulation. Each group consisted of four subgroups: Ctrl, CT, PP242, and CT + PP242. Calcitonin and PP242 were injected on the fourth day of pregnancy and 24 hr later all the mice were killed. Uterine tissue samples were used for morphological analysis and the endometrial epithelial and the stromal cells were isolated from myometrium for evaluation of gene and protein expression. RESULTS: Ovarian stimulation increased the phosphorylation levels of mTOR and ERK1/2 and the expression of miRNA Let-7a. Calcitonin injection increased the expression of HB-EGF, Msx.1, and miRNA Let-7a in a normal ovarian cycle and in ovarian-stimulated mice. It also increased eukaryotic initiation factor 4E-binding protein 1 and ERK1/2 phosphorylation in normal ovarian cycles. CONCLUSION: Calcitonin improved the receptivity of the uterine endometrium by upregulation of the HB-EGF, Msx.1, and miRNA Let-7a likely through mTOR and ERK1/2 signaling pathway.

Semi-quantitative analysis of HOXA11, leukemia inhibitory factor and basic transcriptional element binding protein 1 mRNA expression in the mid-secretory endometrium of patients with endometriosis.

BACKGROUND: HOXA11 and leukemia inhibitory factor (LIF) and basic transcriptional element binding protein1 (BTEB1) are expressed in endometrium throughout the menstrual cycle and show a dramatic increase during the mid-luteal phase at the time of implantation. In this case-control study, the expression pattern of these mRNA was evaluated in patients with endometriosis at the time of implantation. We also describe a semi-quantitative RT-PCR protocol optimized in our laboratory. METHODS: Eight patients with endometriosis were considered as our case and 8 fertile women as control group. Expression levels of HOXA11, LIF and BTEB1 mRNA were measured in endometrium during the mid-secretory phase using semi-quantitative RT-PCR. RESULTS: We describe the detailed procedure for the analysis of HOXA11, LIF and BTEB1 mRNA levels. Endometrial HOXA11 and LIF mRNA expression levels (normalized to beta-actin expression) were significantly decreased in endometrium of infertile patients with endometriosis compared with healthy fertile controls at the time of implantation (P < 0.05). A similar trend was seen in BTEB1 mRNA expression. CONCLUSION: The results suggest that the alteration in expression pattern of the some genes could account for some aspects of infertility in endometriosis.