Integrin αVβ3 and αVβ5 are required for leukemia inhibitory factor-mediated the adhesion of trophoblast cells to the endometrial cells

When the Embryo Meets the Endometrium: Identifying the Features Required for Successful Embryo Implantation

Evaluation of the optimal number of embryos, their quality, and the precise timing for transfer are critical determinants in reproductive success, although still remaining one of the main challenges in assisted reproduction technologies (ART). Indeed, the success of in vitro fertilization (IVF) treatments relies on a multitude of events and factors involving both the endometrium and the embryo. Despite concerted efforts on both fronts, the overall success rates of IVF techniques continue to range between 25% and 30%. The role of the endometrium in implantation has been recently recognized, leading to the hypothesis that both the "soil" and the "seed" play a central role in a successful pregnancy. In this respect, identification of the molecular signature of endometrial receptivity together with the selection of the best embryo for transfer become crucial in ART. Currently, efforts have been made to develop accurate, predictive, and personalized tests to identify the window of implantation and the best quality embryo. However, the value of these tests is still debated, as conflicting results are reported in the literature. The purpose of this review is to summarize and critically report the available criteria to optimize the success of embryo transfer and to better understand current limitations and potential areas for improvement.

The lncRNA LINC00339-encoded peptide promotes trophoblast adhesion to endometrial cells via MAPK and PI3K-Akt signaling pathways

BACKGROUND

Endometrial receptivity (ER), a pivotal event for successful embryo implantation, refers to the capacity of endometrium to allow the adhesion of the trophectoderm of the blastocyst to endometrial cells. In this paper, we set to elucidate whether the peptides encoded by lncRNAs could influence trophoblast cells' adhesion to endometrial cells.

METHODS

WGCNA construction and bioinformatics were used to find out the ER-related lncRNAs with coding potential. Protein analysis was done by immunoblotting and immunofluorescence (IF) microscopy. CCK-8 and Calcein-AM/PI double staining assays were employed to evaluate cell viability. The effect of the peptide on trophoblast spheroids' adhesion to endometrial cells was evaluated. The RNA sequencing (RNA-seq) analysis was applied to identify downstream molecular processes.

RESULTS

lncRNA LINC00339 was found to be related to ER development and it had been predicted to have protein-coding potential. LINC00339 had high occupancy of ribosomes and was confirmed to encode a 49-aa peptide (named LINC00339-205-49aa). LINC00339-205-49aa could promote the attachment of JAR trophoblast spheroids to Ishikawa endometrial cells in vitro. LINC00339-205-49aa also upregulated the expression of E-cadherin in Ishikawa cells. Mechanistically, MAPK and PI3K-Akt signaling pathways were involved in the modulation of LINC00339-205-49aa, which were activated by LINC00339-205-49aa in Ishikawa cells.

CONCLUSION

These data demonstrate that a previously uncharacterized peptide encoded by lncRNA LINC00339 has the ability to enhance JAR trophoblast spheroids' adhesion to Ishikawa endometrial cells, highlighting a new opportunity for the development of drugs to improve ER.

Non-coding RNAs in Recurrent implantation failure

Recurrent implantation failure (RIF), defined as the inability to achieve conception following multiple consecutive in-vitro fertilization (IVF) attempts, represents a complex and multifaceted challenge in reproductive medicine. The emerging role of non-coding RNAs in RIF etiopathogenesis has only gained prominence over the last decade, illustrating a new dimension to our understanding of the intricate network underlying RIF. Successful embryo implantation demands a harmonious synchronization between an adequately decidualized endometrium, a competent blastocyst, and effective maternal-embryonic interactions. Emerging evidence has clarified the involvement of a sophisticated network of non-coding RNAs, including microRNAs, circular RNAs, and long non-coding RNAs, in orchestrating these pivotal processes. Disconcerted expression of these molecules can disrupt the delicate equilibrium required for implantation, amplifying the risk of RIF. This comprehensive review presents an in-depth investigation of the complex role played by non-coding RNAs in the pathogenesis of RIF. Furthermore, it underscores the vast potential of non-coding RNAs as diagnostic biomarkers and therapeutic targets, with the ultimate goal of enhancing implantation success rates in IVF cycles. As ongoing research continues to unravel the intercalated web of molecular interactions, exploiting the power of non-coding RNAs may offer promising avenues for mitigating the challenges posed by RIF and improving the outcomes of assisted reproduction.

Blocked erythroid differentiation and delayed enucleation of erythroblasts may contribute to murine embryonic toxicity upon exposure to low dose of cadmium

Epidemiological and experimental studies have demonstrated the association of spontaneous abortion or embryonic atrophy with heavy metals, including some well-known anemia inducers, such as cadmium (Cd). However, the direct adverse effect of Cd on embryos without inducing maternal anemia remains unclear. In this study, we treated mice with a low dose of Cd before and after mating to minimize Cd-induced maternal anemia. Although most embryos developed normally, embryonic atrophy was still observed in a small percentage of embryos from Cd-exposed pregnant mice. Compared to the embryos from the control pregnant mice, a complete blockage of erythroid differentiation was observed in the atrophic embryos but no obvious alteration of erythroid differentiation in the non-atrophic embryos, respectively. Moreover, our results suggested delayed enucleation of erythroblasts in these non-atrophic embryos. Mechanically, the inhibited iron transport from the placenta to the fetus together with the increased iron export in the fetal livers might contribute to embryonic atrophy and delayed enucleation of erythroblasts upon Cd exposure. Our data may provide new insights into the embryonic toxicity of low-dose Cd.

Decoding the molecular cascade of embryonic-uterine modulators in pregnancy loss of PCOS mother- an "in vivo" study

BACKGROUND

Polycystic ovary syndrome is associated with an increased rate of spontaneous abortion/early pregnancy loss and pups delivered to PCOS animals were abnormal. Currently, assisted reproductive technology has been used to help numerous infertile couples to have their babies. However, there is a low implantation rate after the transfer of embryos. Till now, it could not be concluded whether the reduced pregnancy rates observed were due to abnormal embryos or endometrial modification. Further, transgenic mouse models have been used to find out the molecular deficits behind early pregnancy complications. But, the deletion of crucial genes could lead to systemic deficiencies/embryonic lethality. Also, pregnancy is a complex process with overlapping expression patterns making it challenging to mimic their stage-specific role. Therefore, the motive of the current study was to investigate the probable molecular cascade to decipher the early pregnancy loss in the letrozole-induced PCOS mouse model.

METHODS

PCOS was induced in mice by oral administration of letrozole daily for 21 days. Following, the pregnancy was established and animals were sacrificed on the day 6th of pregnancy. Animals were assessed for early pregnancy loss, hormonal profile, mRNA expression of steroid receptors (Ar, Pr, Esr1/2), decidualization markers (Hox10/11a), adhesion markers (Itgavb3, Itga4b1), matrix metalloproteinases and their endogenous inhibitor (Mmp2/9, Timp1/2) and key mediators of LIF/STAT pathway (Lif, Lifr, gp130, stat3) were analyzed in the embryo implanted region of the uterus. Morphological changes in ovaries and implanted regions of the uterus were assessed.

RESULTS

Mice treated with letrozole demonstrated significant increases in testosterone levels along with a decline in progesterone levels as compared to control animals. PCOS animals also exhibited decreased fertility index and disrupted ovarian and embryo-containing uterus histopathology. Altered gene expression of the steroid receptors and reduced expression of Hox10a, integrins, Mmp9, Timp1/3, Gp130 & Stat3 was observed in the implanted region of the uterus of PCOS animals.

CONCLUSION

Our results reveal that majority of the molecular markers alteration in the establishment of early pregnancy could be due to the aberrant progesterone signaling in the embryonic-uterine tissue of PCOS animals, which further translates into poor fetal outcomes as observed in the current study and in several IVF patients.

Extracellular Vesicles Secreted by Mouse Decidual Cells Carry Critical Information for the Establishment of Pregnancy

The mouse decidua secretes many factors that act in a paracrine/autocrine manner to critically control uterine decidualization, neovascularization, and tissue remodeling that ensure proper establishment of pregnancy. The precise mechanisms that dictate intercellular communications among the uterine cells during early pregnancy remain unknown. We recently reported that conditional deletion of the gene encoding the hypoxia-inducible transcription factor 2 alpha (Hif2α) in mouse uterus led to infertility. Here, we report that HIF2α in mouse endometrial stromal cells (MESCs) acts via the cellular trafficking regulator RAB27b to control the secretion of extracellular vesicles (EVs) during decidualization. We also found that Hif2α-regulated pathways influence the biogenesis of EVs. Proteomic analysis of EVs secreted by decidualizing MESCs revealed that they harbor a wide variety of protein cargoes whose composition changed as the decidualization process progressed. The EVs enhanced the differentiation capacity of MESCs and the production of angiogenic factors by these cells. We also established that matrix metalloproteinase-2, a prominent EV cargo protein, modulates uterine remodeling during decidualization. Collectively, our results support the concept that EVs are central to the mechanisms by which the decidual cells communicate with each other and other cell types within the uterus to facilitate successful establishment of pregnancy.

Yikang decoction facilitates embryo implantation in mice with implantation dysfunction via upregulation of LIF expression

OBJECTIVE

The present study investigates the effects and mechanisms of Yikang decoction on embryo implantation in mice.

METHODS

Totally, mature female mice were randomly divided into four groups: normal, implantation failure (mifepristone treatment), Yikang decoction treatment (mifepristone and Yikang decoction treatment), and control (mifepristone and physiological saline treatment) groups. The efficacy of Yikang decoction was evaluated by the adhesion of uterine endometrial cells. The expression of leukemia inhibitory factor (LIF) and integrin αvβ3 in the endometrium were detected by real-time quantitative PCR and western blot. In addition, mouse endometrial cells were transfected with LIF specific siRNA-1, and the expression of LIF and αvβ3 were detected.

RESULTS

The number of embryos markedly decreased after mifepristone treatment. The adhesion of endometrial cells in the Yikang decoction treatment group significantly increased, when compared to the control group. The expression of LIF and integrin αvβ3 was significantly reduced by mifepristone, but the attenuated expression of LIF and αvβ3 was markedly reversed by treatment with Yikang decoction. In addition, after LIF siRNA-1 transfection, the expression of integrin αvβ3 significantly decreased (P < 0.01). The correlation analysis revealed a significant positive correlation between LIF and αvβ3 protein expression.

CONCLUSION

Yikang decoction can regulate the expression of αvβ3 and increase cell adhesion by upregulating the expression of LIF, thereby improving embryo implantation in mice. These data suggest that Yikang decoction may have therapeutic effect in treating infertility.

Xiaoyao powder improves endometrial receptivity via VEGFR-2-mediated angiogenesis through the activation of the JNK and P38 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaoyao powder (XYP) is a traditional Chinese medicine formula which has wide scope of indications related to liver stagnation, reconcile qi and blood in TCM syndrome. Infertility can induce similar symptoms and signs to the clinical features of liver stagnation syndrome, the treatment of infertility by soothing the liver is obvious. XYP can increase the clinical pregnancy rate, follicle development, oocyte quality and improve endometrial receptivity. However, its underlying pharmacological mechanism of improving endometrial receptivity is unclear.

AIM OF THE STUDY

The aim of the study was to investigate the effect of XYP on pregnancy rates and endometrial angiogenesis, to determine the potent mechanism in association with the pro-angiogenic behavior which closely related to improving endometrial receptivity.

MATERIALS AND METHODS

We established an animal model exhibiting decreasing endometrial receptivity by controlled ovarian hyperstimulation and a human endometrial microvascular endothelial cell (HEMEC) model. Endometrial morphology was observed by hematoxylin-eosin staining and Scanning electron microscopy. Western blot and qRT-PCR analysis were used to detect expression of PCNA, Cyclin D1, MMP9 and MAPK signaling pathway. Scratch-wound assay and tube formation assay were used to observe HEMEC migration and tubulogenesis.

RESULTS

The results demonstrated that XYP pretreatment could improve endometrial receptivity, which leads to high pregnancy rates. In the endometrium, XYP facilitated angiogenesis by promoting tube formation. XYP could enhance HEMEC proliferation and migration induced by VEGF, which were observed by the microscope and Scratch-wound assays. XYP promoted HEMEC proliferation and migration via the p38 and JNK MAPK signaling pathways.

CONCLUSION

XYP promotes HEMEC proliferation and migration via the P38 and the JNK MAPK signaling pathways, which contribute to the endometrial angiogenesis mediated by VEGFR-2 that is favorable for endometrial receptivity. We firstly elucidated the molecular mechanisms by which XYP improved endometrial receptivity by promoting angiogenesis.

Peri-implantation expression and regulation of ITGB8 in goat uterus

Ruminants have a superficial implantation pattern. The extended conceptus attaches to the receptive endometrium to form the cotyledonary placenta. During the attachment, a large number of events occur at the maternal-fetal interface. However, the related molecular mechanisms have not been fully understood. Integrin beta8 (ITGB8) is a subunit of integrin beta involved in embryo implantation. In this study, we determined peri-implantation expression and regulation of ITGB8 in goat uterus. The mRNA and protein levels of ITGB8 were both high in goat endometrial luminal epithelium (LE) and superficial glandular epithelium (sGE) during the adhesion period (Days 16-19 of pregnancy). Such expression profile was opposite to that of microRNA-187 (miR-187). Then, we validated that miR-187 targeted the 3' untranslated region (UTR) of ITGB8 in primary goat endometrial epithelial cells (EECs). In EECs, inhibition of miR-187 resulted in not only up-regulated ITGB8 level but also reduced cell proliferation and focal adhesion kinase (FAK) activity. Moreover, ITGB8 and miR-187 were regulated by interferon tau (IFNT). Altogether, in goat, the miR-187/ITGB8 axis may be involved in conceptus attachment and is downstream of IFNT. Our results will help us better understand the mechanisms of ruminant implantation and may provide a useful tool to improve the reproduction ratio for ruminants.

Mycotoxin deoxynivalenol affects myoblast differentiation via downregulating cytoskeleton and ECM-integrin-FAK-RAC-PAK signaling pathway

As a common mycotoxin, deoxynivalenol (DON) contaminates cereal grains and feed in field or during processing and storage. DON elicits a spectrum of adverse effects in animals including anorexia and growth retardation. Especially, the presence of DON has also been detected in muscle, suggesting that DON may has the potential to affect the development of muscle. However, the relevant research is very rare and the molecular mechanism remains unclear. Myoblasts differentiation into multinucleated myotubes is one of the crucial steps of skeletal muscle development. In the present study, we investigated the effects of DON on differentiation of myoblasts using murine C2C12 cells model. The results indicated that DON dose-dependent inhibited the formation of myotubes in C2C12 cells. After performing omics techniques, a total of 149 differentially expressed genes were identified. The expression of cytoskeleton proteins and extracellular matrix (ECM) proteins were downregulated by DON. Furthermore, DON significantly downregulated the expression of integrin αv and integrin β5, leading to inhibition of the ECM-integrin receptor interaction. The focal adhesion kinase (FAK) and phosphorylated forms, ras-related C3 botulinum toxin substrate (RAC) and p21-activated kinases 1 (PAK1) were also downregulated by DON. Taken together, our findings suggest that DON has the potent to affect the differentiation of myoblasts via downregulating of cytoskeleton and ECM-integrin-FAK-RAC-PAK signaling pathway.

Sildenafil citrate-loaded targeted nanostructured lipid carrier enhances receptivity potential of endometrial cells via LIF and VEGF upregulation

The main objective of this research is to prepare sildenafil citrate (SC)-loaded arginyl-glycyl-aspartic acid (RGD)-containing nanostructured lipid carrier (SC-loaded NLC-RGD) and evaluate their effects on the receptivity potential of endometrial cells. Hot homogenization method was used to prepare SC-loaded NLC-RGD. Then, size, drug encapsulation, and morphology of prepared nanoparticles were studied by photon correlation spectroscopy technic, ultrafiltration method, and scanning electron microscopy, respectively. Subsequently, the influence of SC-loaded NLC-RGD on endometrial receptivity was evaluated by in vitro implantation assay. Finally, expression of vascular endothelial growth factor (VEGF), leukemia inhibitory factor (LIF), and integrin beta 3 (as endometrial receptivity markers) was assessed in SC-loaded NLC-RGD-treated endometrial cells by reverse transcription polymerase chain reaction (RT-PCR). Particles with a nano-size diameter (92.7 nm), appropriate polydispersity index (0.21), spherical morphology, and acceptable loading efficiency were prepared. In vitro implantation assay showed that SC, SC-loaded NLC, and SC-loaded NLC-RGD improve the rate of endometrial attachment potential by 1.6 ± 0.4, 1.7 ± 0.3, and 2.3 ± 0.3 times, respectively. Analysis of RT-PCR results showed the enhancing mRNA of LIF and VEGF in SC-treated endometrial cells. Results also confirmed the higher influence of SC-loaded NLC-RGD on gene expression patterns in comparison to SC. Using NLC-RGD as a carrier to deliver SC to endometrial cells is an effective approach to improve endometrial receptivity. Upregulation of LIF and VEGF is the probable mechanism by which SC enhances the endometrial receptivity potential.

Mechanistic perspectives on differential mitochondrial-based neuroprotective effects of several carnitine forms in Alzheimer's disease in vitro model

Mitochondrial deregulation has emerged as one of the earliest pathological events in Alzheimer's disease (AD), the most common age-related neurodegenerative disorder. Improvement of mitochondrial function in AD has been considered a relevant therapeutic approach. L-carnitine (LC), an amino acid derivative involved in the transport of long-chain fatty acids into mitochondria, was previously demonstrated to improve mitochondrial function, having beneficial effects in neurological disorders; moreover, acetyl-L-carnitine (ALC) is currently under phase 4 clinical trial for AD (ClinicalTrials.gov NCT01320527). Thus, in the present study, we investigated the impact of different forms of carnitines, namely LC, ALC and propionyl-L-carnitine (PLC) on mitochondrial toxicity induced by amyloid-beta peptide 1-42 oligomers (AβO; 1 μM) in mature rat hippocampal neurons. Our results indicate that 5 mM LC, ALC and PLC totally rescued the mitochondrial membrane potential and alleviated both the decrease in oxygen consumption rates and the increase in mitochondrial fragmentation induced by AβO. These could contribute to the prevention of neuronal death by apoptosis. Moreover, only ALC ameliorated AβO-evoked changes in mitochondrial movement by reducing the number of stationary mitochondria and promoting reversal mitochondrial movement. Data suggest that carnitines (LC, ALC and PLC) may act differentially to counteract changes in mitochondrial function and movement in neurons subjected to AβO, thus counteracting AD-related pathological phenotypes.

GLUT4 in Mouse Endometrial Epithelium: Roles in Embryonic Development and Implantation

GLUT4 is involved in rapid glucose uptake among various kinds of cells to contribute to glucose homeostasis. Prior data have reported that aberrant glucose metabolism by GLUT4 dysfunction in the uterus could be responsible for infertility and increased miscarriage. However, the expression and precise functions of GLUT4 in the endometrium under physiological conditions remain unknown or controversial. In this study, we observed that GLUT4 exhibits a spatiotemporal expression in mouse uterus on pregnant days 1–4; its expression especially increased on pregnant day 4 during the window of implantation. We also determined that estrogen, in conjunction with progesterone, promotes the expression of GLUT4 in the endometrial epithelium in vivo or in vitro. GLUT4 is an important transporter that mediates glucose transport in endometrial epithelial cells (EECs) in vitro or in vivo. In vitro, glucose uptake decreased in mouse EECs when the cells were treated with GLUT4 small interfering RNA (siRNA). In vivo, the injection of GLUT4-siRNA into one side of the mouse uterine horns resulted in an increased glucose concentration in the uterine fluid on pregnant day 4, although it was still lower than in blood, and impaired endometrial receptivity by inhibiting pinopode formation and the expressions of leukemia inhibitory factor (LIF) and integrin ανβ3, finally affecting embryonic development and implantation. Overall, the obtained results indicate that GLUT4 in the endometrial epithelium affects embryo development by altering glucose concentration in the uterine fluid. It can also affect implantation by impairing endometrial receptivity due to dysfunction of GLUT4.

The Disorders of Endometrial Receptivity in PCOS and Its Mechanisms

Polycystic ovary syndrome (PCOS) is a mysterious and complicated endocrine disease with the combination of metabolic, reproductive, psychological dysfunctions. Impaired endometrial receptivity and ovulation disorders/anovulation are both important causes of PCOS-related infertility. However, change in endometrium has never received the same attention as ovulatory dysfunction. Besides, putting emphasis on endometrial function may be more realistic for PCOS-related infertility, given the wide use of assisted reproductive technology. The present review focuses on the disorders of endometrial receptivity of patients with PCOS, summarizes the changes of the indicators of endometrial receptivity including leukemia inhibitory factor, homeobox genes A, pinopodes, αvβ3-integrin, and intercellular junctions and also analyzes the possible mechanisms of decreased endometrial receptivity and its relationship with the main endocrine and metabolic disorders of PCOS such as hyperandrogenism, inflammation, insulin resistance, and obesity. Despite several biomarkers have been found to be associated with decreased endometrial receptivity in PCOS, the clinical relevance of these findings still awaits future clarification.

Paeoniflorin Enhances Endometrial Receptivity through Leukemia Inhibitory Factor

Despite advances in assisted reproductive technology, treatment for deficient endometrial receptivity is a major clinical unmet need. In our previous study, the water extract of Paeonia lactiflora Pall. enhanced endometrial receptivity in vitro and in vivo via induction of leukemia inhibitory factor (LIF), an interleukin (IL)-6 family cytokine. In the present study, we found that paeoniflorin, a monoterpene glycoside, is the major active compound of P. lactiflora. Paeoniflorin significantly improved the embryo implantation rate in a murine model of mifepristone (RU486)-induced implantation failure. In addition, paeoniflorin increased the adhesion of human trophectoderm-derived JAr cells to endometrial Ishikawa cells through the expression of LIF in vitro. Moreover, using the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) database of the human endometrium, we confirmed that LIF signaling is a key regulator for improving human endometrial receptivity. Therefore, these results suggest that paeoniflorin might be a potent drug candidate for the treatment of endometrial implantation failure by enhancing endometrial receptivity.

The ameliorating effects of tokishakuyakusan in a rat model of implantation failure involves endometrial gland leukemia inhibitory factor and decidualization

ETHNOPHARMACOLOGICAL RELEVANCE

Tokishakuyakusan (TSS) is a Kampo medicine that is prescribed for the treatment of infertility in Japan. However, its precise mechanism of action remains unclear.

AIM OF THE STUDY

Leukemia inhibitory factor (LIF) in the endometrium plays an indispensable role in embryo implantation and is linked to infertility or implantation failure. Previously, we demonstrated that TSS ameliorated implantation failure induced by mifepristone (RU-486), an antagonist of progesterone, in rats. Herein, we aimed to clarify whether the ameliorating effect of TSS on implantation failure in the rat model involves endometrial LIF. Additionally, we determined whether decidualization, the dysfunction of which is linked to infertility or implantation failure similar to LIF, progesterone, and other implantation-related factors, are involved in the effect of TSS.

MATERIALS AND METHODS

The implantation failure rat model was developed via the subcutaneous administration of RU-486 (7 mg/kg) on day 3 post-coitus. Sesame oil was administered as the vehicle control. Rats were fed a diet containing 1% or 3% TSS or a control diet from day 13 pre-coitus. Subsequently, the implantation sites were assessed, and plasma progesterone levels were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) on day 8 post-coitus. The LIF mRNA of the endometrial gland, which was segmented via laser-microdissection from the endometrial tissue, was measured, and endometrial LIF immunostaining was carried out on day 5. The gene expression of different factors related to implantation, including decidualization and progesterone-responsiveness on days 5 and 6, were measured. The human endometrial Ishikawa cell line derived from human adenocarcinoma was treated with TSS (30-300 μg/mL) for 24 h, and the LIF concentrations in the cell culture supernatants were measured.

RESULTS

RU-486 decreased the number of implantation sites in the uterus of rats; however, the decrease was significantly alleviated by TSS (3%-diet), which tended to increase plasma progesterone. In rats with RU-486-induced implantation failure, endometrial gland LIF mRNA and endometrial LIF protein were markedly decreased while the gene expression of both decidualization-related factors such as interleukin-11, insulin-like growth factor binding protein-1, and cyclooxygenase-2, and progesterone responsive-related factors such as FK506 binding protein 5, were significantly decreased. These changes in the uterus of rats with implantation failure were significantly alleviated by TSS (3%-diet). Additionally, TSS significantly enhanced LIF protein production and LIF mRNA in Ishikawa cells.

CONCLUSIONS

The mechanism whereby TSS ameliorates RU-486-induced implantation failure in rats may involve the alleviation of decreased LIF production derived from the endometrial gland, and a dysfunction of decidualization, including lower progesterone responsiveness in the model. These findings may partly contribute to the interpretation of the beneficial effects of TSS on infertility.

Biogenesis and functions of circular RNAs and their role in diseases of the female reproductive system

A member of the newly discovered RNA family, circular RNA (circRNA) is considered as the intermediate product of by-product splicing or abnormal RNA splicing. With the development of RNA sequencing, circRNA has recently drawn research interest. CircRNA exhibits stability, species conservatism, and tissue cell specificity. It acts as a miRNA sponge in the circRNA-microRNA (miRNA-mRNA axis, which can regulate gene transcription and protein translation. Studies have confirmed that circRNA is ubiquitous in eukaryotic cells, which play an important role in the regulation of human gene expression and participate in the occurrence and development of various human diseases. CircRNA may be closely related to the occurrence and development of female reproductive system diseases. By analyzing the biological functions and mechanism of circRNA, we find that circRNA has certain development prospects as biomarkers of the female reproductive system diseases. The production and degradation of circRNA, biological functions, and their association with the occurrence of diseases of female reproductive system are reviewed in this article.

Determining the Molecular Background of Endometrial Receptivity in Adenomyosis

Background: Adenomyosis is a gynaecological condition with limited evidence of negative impact to endometrial receptivity. It is commonly associated with endometriosis, which has been shown to alter endometrial expression patterns. Therefore, the candidate genes identified in endometriosis could serve as a source to study endometrial function in adenomyosis. Methods: Transcripts/proteins associated with endometrial receptivity in women with adenomyosis or endometriosis and healthy women were obtained from publications and their nomenclature was adopted according to the HUGO Gene Nomenclature Committee (HGNC). Retrieved genes were analysed for enriched pathways using Cytoscape/Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and Reactome tools to prioritise candidates for endometrial receptivity. These were used for validation on women with (n = 9) and without (n = 13) adenomyosis. Results: Functional enrichment analysis of 173, 42 and 151 genes associated with endometriosis, adenomyosis and healthy women, respectively, revealed signalling by interleukins and interleukin-4 and interleukin-13 signalling pathways, from which annotated LIF, JUNB, IL6, FOS, IL10 and SOCS3 were prioritised. Selected genes showed downregulated expression levels in adenomyosis compared to the control group, but without statistical significance. Conclusion: This is the first integrative study providing putative candidate genes and pathways characterising endometrial receptivity in women with adenomyosis in comparison to healthy women and women with endometriosis.

Assessment of Anti-Mullerian Hormone and Anti-Mullerian Hormone Type II Receptor Variants in Women with Repeated Implantation Failures

Repeated implantation failure (RIF) is a common endocrine disease that causes female infertility and the etiology is unknown. The abnormal expression of key proteins and hormones at the maternal-fetal interface affected the maternal-fetal communication and leads to adverse pregnancy outcomes. The expression of anti-Mullerian hormone (AMH) and AMH receptor II (AMHRII) was observed in the endometrium. This study aimed to investigate the expression of AMH and AMHRII at the human endometrium, decidual tissue, and blastocyst. Furthermore, the expression of AMH and AMHRII were examined in the RIF patients using immunohistochemistry and quantitative real-time PCR to test the AMHRII expression. The results demonstrated that AMH and AMHRII were present in healthy endometrium and AMHRII was highly expressed in mid-luteal phase. In addition, AMHRII expression was detected throughout the pregnancy and AMHRII's highest expression was in the second trimester. AMHRII was expressed in the blastocysts; however, AMH was not observed. The positive expression rate for AMHRII was significantly higher in the endometrium from RIF. Estrogen receptor (ER), insulin-like growth factor binding protein 1(IGFBP1), and prolactin (PRL) were significantly less expressed in RIF with high expression of AMHRII. The apoptosis was significantly higher in patients with high expression of AMHRII than in patients with normal expression of AMHRII. Our data suggests that AMHRII had an effect on RIF via the AMH and AMHRII signaling pathway. It participated in the development of RIF by interfering with endometrial decidualization and apoptosis.

Influence of Follicular Fluid and Seminal Plasma on The Expression of Endometrial Receptivity Genes in Endometrial Cells

Objective

Endometrial receptivity plays a key role in pregnancy success in assisted reproduction cycles. Recent evidence suggests that seminal plasma (SP) and follicular fluid (FF) influence the uterine endometrium to improve implantation of the embryo and the establishment of pregnancy. In this study, we attempt to assess the influence of FF and SP on the expression levels of main endometrial receptivity genes (HOXA10, HOXA11, ITGAV, ITGB3 and LIF) in endometrial stromal cells.

Materials and Methods

In this experimental study, SP and FF were collected from 15 healthy fertile men and 15 healthy fertile women, respectively. Tissue specimens of the endometrium were obtained from 12 women undergoing hysterectomy for benign conditions. After endometrial stromal cell isolation and culture, dose- and time-dependent cytotoxic effects of pooled FF and SP on 3D-cultured endometrial cells were evaluated. A second independent set of 12 endometrium samples was treated under determined optimum conditions and evaluated for gene expression analysis using quantitative real-time polymerase chain reaction (qRT-PCR).

Results

The results of this study indicated that exposure of endometrial stromal cells to FF resulted in the elevated expression of HOXA10 (fold change=2.6, P=0.02), HOXA11 (fold change=3.3, P=0.002), LIF (fold change=4.6, P=0.0003), ITGB3 (fold change=3.5, P=0.012), and ITGAV (fold change=2.8, P=0.001) compared to untreated cells. In addition, we found that SP-treated endometrial cells showed increased mRNA levels of only the LIF gene (fold change=2.5, P=0.008) compared to untreated cells.

Conclusion

Human SP and FF may modulate the endometrial receptivity and improve the implantation rate in assisted reproduction cycles through the up-regulation of endometrial receptivity genes.

Promoting Roles of Embryonic Signals in Embryo Implantation and Placentation in Cooperation with Endocrine and Immune Systems

Embryo implantation in the uterus is an essential process for successful pregnancy in mammals. In general, the endocrine system induces sufficient embryo receptivity in the endometrium, where adhesion-promoting molecules increase and adhesion-inhibitory molecules decrease. Although the precise mechanisms remain unknown, it is widely accepted that maternal–embryo communications, including embryonic signals, improve the receptive ability of the sex steroid hormone-primed endometrium. The embryo may utilize repulsive forces produced by an Eph–ephrin system for its timely attachment to and subsequent invasion through the endometrial epithelial layer. Importantly, the embryonic signals are considered to act on maternal immune cells to induce immune tolerance. They also elicit local inflammation that promotes endometrial differentiation and maternal tissue remodeling during embryo implantation and placentation. Additional clarification of the immune control mechanisms by embryonic signals, such as human chorionic gonadotropin, pre-implantation factor, zona pellucida degradation products, and laeverin, will aid in the further development of immunotherapy to minimize implantation failure in the future.

Identification of differentially expressed microRNAs in outgrowth embryos compared with blastocysts and non-outgrowth embryos in mice

Recurrent implantation failure (RIF) is one of the main causes for the repeated failure of IVF, and the major reason for RIF is thought to be a miscommunication between the embryo and uterus. However, the exact mechanism underlying embryo-uterus cross-talk is not fully understood. The aim of the present study was to identify differentially expressed microRNAs (miRNAs) among blastocysts, non-outgrowth and outgrowth embryos in mice using microarray analysis. A bioinformatics analysis was performed to predict the potential mechanisms of implantation. The miRNA expression profiles differed significantly between non-outgrowth and outgrowth embryos. In all, 3163 miRNAs were detected in blastocysts and outgrowth embryos. Of these, 10 miRNA candidates (let-7b, miR-23a, miR-27a, miR-92a, miR-183, miR-200c, miR-291a, miR-425, miR-429 and miR-652) were identified as significant differentially expressed miRNAs of outgrowth embryos by in silico analysis. The expression of the miRNA candidates was markedly changed during preimplantation embryo development. In particular, let-7b-5p, miR-200c-3p and miR-23a-3p were significantly upregulated in outgrowth embryos compared with non-outgrowth blastocysts. Overall, differentially expressed miRNAs in outgrowth embryos compared with blastocysts and non-outgrowth embryos could be involved in embryo attachment, and interaction between the embryo proper and maternal endometrium during the implantation process.

Spatial organization of endometrial gene expression at the onset of embryo attachment in pigs

BACKGROUND

During the preimplantation phase in the pig, the conceptus trophoblast elongates into a filamentous form and secretes estrogens, interleukin 1 beta 2, interferons, and other signaling molecules before attaching to the uterine epithelium. The processes in the uterine endometrium in response to conceptus signaling are complex. Thus, the objective of this study was to characterize transcriptome changes in porcine endometrium during the time of conceptus attachment considering the specific localization in different endometrial cell types.

RESULTS

Low-input RNA-sequencing was conducted for the main endometrial compartments, luminal epithelium (LE), glandular epithelium (GE), blood vessels (BV), and stroma. Samples were isolated from endometria collected on Day 14 of pregnancy and the estrous cycle (each group n = 4) by laser capture microdissection. The expression of 12,000, 11,903, 11,094, and 11,933 genes was detectable in LE, GE, BV, and stroma, respectively. Differential expression analysis was performed between the pregnant and cyclic group for each cell type as well as for a corresponding dataset for complete endometrium tissue samples. The highest number of differentially expressed genes (DEGs) was found for LE (1410) compared to GE, BV, and stroma (800, 1216, and 384). For the complete tissue, 3262 DEGs were obtained. The DEGs were assigned to Gene Ontology (GO) terms to find overrepresented functional categories and pathways specific for the individual endometrial compartments. GO classification revealed that DEGs in LE were involved in 'biosynthetic processes', 'related to ion transport', and 'apoptotic processes', whereas 'cell migration', 'cell growth', 'signaling', and 'metabolic/biosynthetic processes' categories were enriched for GE. For blood vessels, categories such as 'focal adhesion', 'actin cytoskeleton', 'cell junction', 'cell differentiation and development' were found as overrepresented, while for stromal samples, most DEGs were assigned to 'extracellular matrix', 'gap junction', and 'ER to Golgi vesicles'.

CONCLUSIONS

The localization of differential gene expression to different endometrial cell types provided a significantly improved view on the regulation of biological processes involved in conceptus implantation, such as the control of uterine fluid secretion, trophoblast attachment, growth regulation by Wnt signaling and other signaling pathways, as well as the modulation of the maternal immune system.

Enhancement of Endometrial Receptivity by Cnidium officinale through Expressing LIF and Integrins

Improvement of endometrial receptivity is necessary for successful embryo implantation, and its impairment is associated with female infertility. In this study, we investigated the effect of the roots of Cnidium officinale Makino (CoM) on endometrial receptivity in both in vitro and in vivo model of embryo implantation. We found that CoM enhanced the adhesion of JAr cells to Ishikawa cells by stimulating expression of leukemia inhibitory factor (LIF) and integrins. In addition, blocking of LIFR using hLA or neutralization of integrins αV, β3, and β5 using antibodies significantly reduced the enhanced adhesion between JAr cell and CoM-treated Ishikawa cells, indicating that LIF and integrin play an important role in trophoblast-endometrium adhesion for embryo implantation. Furthermore, we identified that CoM significantly improved the implantation rate of blastocysts in the mouse model of RU-induced implantation failure. By collecting these results, here, we suggest that CoM has a therapeutic potential against female infertility associated with decreased endometrial receptivity.

Circular RNAs in gynecological disease: promising biomarkers and diagnostic targets

Circular RNAs (circRNAs) are a category of RNA molecules with covalently closed circles lacking both a 5′ cap and a 3′ tail. In recent years, circRNAs have attracted much attention and become a research hotspot of the RNA field following miRNAs and lncRNAs. CircRNAs exhibit tissue specificity, structural stability, and evolutionary conservation. Although the biological effects of circRNAs are still underestimated, many studies have shown that circRNAs have functions including regulation of transcription, translation into proteins and miRNA sponges. In this review, we briefly described the biogenesis and function of circRNAs and present circular transcripts in gynecological disease.

Effect of metabolic status on conceptus-maternal interactions on day 19 in dairy cattle: II. Effects on the endometrial transcriptome

The aim of this study was to test the hypothesis that the metabolic stresses associated with lactation alter the ability of the endometrium to respond appropriately to the conceptus by examining endometrial gene expression on day 19 of pregnancy. Immediately after calving, primiparous Holstein cows with similar production and fertility estimated breeding values were randomly divided into two groups and either dried off (i.e. never milked) immediately or milked twice daily. Approximately 65-75 days postpartum, grade 1 blastocysts recovered from superovulated Holstein heifer donors (n = 5) were transferred (1 per recipient) into lactating (n = 11) and nonlactating (n = 11) recipients. Control nulliparous Holstein heifers (n = 6) were artificially inseminated. RNA-sequencing was performed on intercaruncular endometrial samples recovered at slaughter from confirmed pregnant animals on day 19 (n = 5 lactating and nonlactating cows; n = 4 heifers). Differentially expressed genes (DEGs) were identified between both postpartum groups compared to heifers and between lactating and nonlactating cows. Functional annotation of DEGs between cows and heifers revealed over-representation of categories, including endosome, cytoplasmic vesicle, endocytosis, regulation of exocytosis, and cytokine receptor activity. Functional categories including transcription factor binding sites, cell motility, and cell migration were enriched for DEGs between endometria from lactating and nonlactating cows. In conclusion, while the evidence for a major effect of lactation on the endometrial transcriptome is relatively weak, these data suggest that the metabolic status of the animal (heifer vs cow) modulates the response of the endometrium to the developing conceptus.

Morphological, Ultrastructural, and Molecular Aspects of In Vitro Mouse Embryo Implantation on Human Endometrial Mesenchymal Stromal Cells in The Presence of Steroid Hormones as An Implantation Model

Objective

This experimental study aimed to evaluate the effects of 17β-estradiol (E2) and progesterone (P4) on the interaction between mouse embryo and human endometrial mesenchymal stromal cells, and gene expressions related to implantation [αV and β3 integrins, interleukin-1 receptor (IL-1R), and leukemia inhibitory factor receptor (LIFR)] using an in vitro two- dimensional model.

Materials and Methods

In this experimental study, the endometrial stromal cells were isolated enzymatically and mechanically, and cultured to the fourth passage. Next, their immunophenotype was confirmed by flow cytometric analysis as mesenchymal stromal cells. The cells were cultured as either the experimental group in the presence of E2 (0.3 nmol) and P4 (63.5 nmol) or control group without any hormone treatment. Mouse blastocysts were co-cultured with endometrial mesenchymal stromal cells in both groups for 48 hours. Their interaction was assessed under an inverted microscope and scanning electron microscopy (SEM). Expressions of αV and β3 integrins, LIFR, and IL-1R genes were analyzed by real-time reverse transcription-polymerase chain reaction (RT-PCR).

Results

Similar observations were seen in both groups by light microscopy and SEM. We observed the presence of pinopode-like structures and cell secretions on the apical surfaces of endometrial mesenchymal stromal cells in both groups. The trophoblastic cells expanded and interacted with the mesenchymal monolayer cells. At the molecular level, expression of IL-1R significantly increased in the hormonal treated group compared to the control (P≤0.05). Expressions of the other genes did not differ.

Conclusion

This study has shown that co-culture of endometrial mesenchymal stromal cells with mouse embryo in media that contained E2 (0.3 nmol) and P4 (63.5 nmol) could effectively increase the expression of IL-1R, which is involved in embryo implantation. However, there were no significant effects on expressions of αV and β3 integrins, LIFR, and on the morphology and ultrastructure of endometrial mesenchymal stromal cells.

Endogenous annexin A1 (AnxA1) modulates early-phase gestation and offspring sex-ratio skewing

Annexin A1 (AnxA1) is a glucocorticoid-regulated anti-inflammatory protein secreted by phagocytes and other specialised cells. In the endocrine system, AnxA1 controls secretion of steroid hormones and it is abundantly expressed in the testis, ovaries, placenta and seminal fluid, yet its potential modulation of fertility has not been described. Here, we observed that AnxA1 knockout (KO) mice delivered a higher number of pups, with a higher percentage of female offsprings. This profile was not dependent on the male features, as sperm from KO male mice did not present functional alterations, and had an equal proportion of Y and X chromosomes, comparable to wild type (WT) male mice. Furthermore, mismatched matings of male WT mice with female KO yielded a higher percentage of female pups per litter, a phenomenon which was not observed when male KO mice mated with female WT animals. Indeed, AnxA1 KO female mice displayed several differences in parameters related to gestation including (i) an arrested estrous cycle at proestrus phase; (ii) increased sites of implantation; (iii) reduced pre- and post-implantation losses; (iv) exacerbated features of the inflammatory reaction in the uterine fluid during implantation phase; and (v) enhanced plasma progesterone in the beginning of pregnancy. In summary, herein we highlight that AnxA1 pathway as a novel determinant of fundamental non-redundant regulatory functions during early pregnancy.

AlphaVBeta3 Integrin expression within uterine endometrium in unexplained infertility: a prospective cohort study

BACKGROUND

Implantation defect is one of these contributing factors for unexplained infertility. In the mid-luteal phase, when implantation is expected to happen, Integrins expression is remarkably increased. So, Integrins could potentially serve as markers for the frame of the window of implantation. αVβ3 integrin could have a role as a potential receptor for embryonic attachment. The aim of the current study is to investigate whether the women with unexplained infertility have a pattern of expression of endometrial αvβ3 integrin that could differ from those who have normal fertility or not.

METHOD

Two groups of women have been included in this study. The first group was the Unexplained Infertility Group. This group included women diagnosed with unexplained primary infertility. The second group was the fertile Group, which included fertile parous women presented to the family planning clinic seeking contraception. 2D transvaginal ultrasound scan (TVS) was performed six days after detecting urinary LH surge. (TVS) was used to measure endometrial thickness, and subendometrial blood flow color Doppler Resistance Index (RI). On the same day of transvaginal ultrasound, endometrial samples were taken using the Endocell® office suction sampler for Immunohistochemistry (IHC) study using monoclonal mouse IgG antibodies to detect endometrial αvβ3 integrin.

RESULTS

Thirty-five fertile women with a diagnosis of unexplained infertility were included as a group I [Unexplained infertility Group] along with an equal number of fertile women as group II [Fertile Group]. The group of women with a diagnosis of unexplained infertility had a significantly lower αvβ3 integrin score when compared to the fertile group (median score 0, range:0-2 and median score 1, range: 1-3 and for infertile and fertile groups respectively, P < 0.0001). In addition, the unexplained infertility group had significantly higher subendometrial flow RI and Significantly thinner endometrial thickness.

CONCLUSION

This study showed that Alpha v Beta 3 integrin is a significantly lower in endometrium in cases of unexplained infertility, which may suggest that underexpression of Alpha v Beta 3 integrin in human endometrium could be linked to defective uterine receptivity, and play a role as an unrecognized cause of infertility in this population of women. We need larger studies of adequate statistical power, ideally investigating more than one menstrual cycle in the same woman, to investigate the usefulness of using these molecular molecules in clinical practice.

Colony stimulating factor-1 and leukemia inhibitor factor expression from current-cycle cannula isolated endometrial cells are associated with increased endometrial receptivity and pregnancy

Background

Poor endometrial quality is associated with more than a third of embryo implantation failures. Current ultrasonography technology lacks the capacity to determine efficiently the endometrial receptivity during ongoing cycle transfers. We analyzed the relationship between the gene expression profile associated with implantation and clinical pregnancy from endometrial cells taken during embryo transfer.

Methods

Seventy-six patients submitted to a standard ovarian stimulation protocol, in vitro fertilization, and good quality embryos were collected (morphological assessment). Endometrial samples were taken with ultrasonography guidance and cells were Hematoxylin and Eosin stained for morphological identification. Total RNA was extracted and the expression of Mucin 1 (MUC1), Homeobox A10 (HOXA-10), Leukemia Inhibitor Factor (LIF), Colony Stimulating Factor-1 (CSF-1), and ribosomal 18 s (endogenous control) were analyzed using RT-qPCR. Presence of a gestational sac, β-hGC (≥10 mIU/mL on Day 20), and a fetal heartbeat were used to determine a positive embryo implantation and pregnancy.

Results

Samples collected from same cycle embryo transfer showed clear morphological staining for endometrial cells (80–90% of the cells). Cells in the sample were molecularly identified as the endometrium (HOXA-10 positive and MUC-1 negative). CSF-1 expression was 4.55-fold and LIF expression was 12.25-fold higher in patients who became pregnant. Both increases were statistically significant (p < 0.05).

Conclusions

Here, we provide evidence of a new method to assess endometrial receptivity. Furthermore, we demonstrate that the expression profile, based on LIF and CSF-1, showed a difference between a receptive and a non-receptive endometrium.

Water-extracted tubers of Cyperus rotundus L. enhance endometrial receptivity through leukemia inhibitory factor-mediated expression of integrin αVβ3 and αVβ5

ETHNOPHARMACOLOGICAL RELEVANCE

Cyperus rotundus L. (CR) has been traditionally used as an herbal medicine in Asian countries to treat diverse gynecological disorders. However, the potential therapeutic effect of CR on endometrial receptivity for successful embryo implantation to treat female infertility has not been fully studied.

AIM OF STUDY

The aim of this study was to evaluate the effect of water-extracted CR on endometrial receptivity by investigating the expression of leukemia inhibitory factor (LIF) and integrins, cell adhesion, and embryo implantation using mifepristone (RU486; RU)-induced implantation failure model.

MATERIALS AND METHODS

The water extract of CR was prepared and fingerprinted using high-performance liquid chromatography (HPLC). For the expression and regulation of LIF, reverse transcription polymerase chain reaction (RT-PCR) and western blotting were performed in CR-stimulated Ishikawa cells. To evaluate LIF-mediated integrin expression, knockdown of LIF by shRNA was performed in Ishikawa cells. The effect of CR on endometrial receptivity was determined by an in vitro adhesion assay between JAr cells and CR-induced Ishikawa cells. In vivo, C57BL/6 female mice (n = 7 per group) orally received CR (31.68mg/kg/day), a similar dose as used clinically. Seven days after CR treatment, all female mice were caged with male mice until pregnancy was verified. On day 4 of pregnancy, RU (4mg/kg) was injected subcutaneously to induce embryo implantation failure.

RESULT

CR increased the expression of LIF through the phosphatidylinositol-3-kinase/ protein kinase B (PI-3K/AKT) signaling pathway in Ishikawa cells. In addition, CR enhanced adhesion of JAr cells onto Ishikawa cells by inducing the expression of LIF-dependent integrins αVβ3 and αVβ5. Furthermore, CR improved the number of implantation sites in pregnant mice despite RU injection.

CONCLUSION

CR increased the expression of LIF-mediated integrins αVβ3 and αVβ5 on the surface of endometrial cells, which is associated with adhesion of trophoblastic cells to endometrial cells for blastocyst implantation. Our findings provide evidence that CR has therapeutic potential against poor endometrial receptivity.

Insufficient Angiogenesis: Cause of Abnormally Thin Endometrium in Subfertile Patients?

INTRODUCTION

This study investigated subfertile patients with abnormally thin endometrium after infertility treatment. As they had adequate serum concentrations of hormones, an endometrial factor for subfertility was suspected.

METHODS

To elucidate the cause of subfertility, endometrial biopsies were taken in each patient in the late proliferative and mid-secretory phases of one menstrual cycle. Endometrial biopsies from women with normal menstrual cycles and confirmed fertility who were undergoing hysterectomy for benign uterine disease were used as positive controls. The tissue samples were investigated for steroid hormone receptor expression and for the proliferation marker Ki-67. Immunohistochemistry was performed with antibodies against the marker molecules for endometrial receptivity - β ₃ integrin, VEGF, LIF, and CD56 (large granular lymphocytes, LGLs).

RESULTS

The steroid hormone receptors for estrogen (E2) and progesterone (P) were expressed normally (at the first biopsy) and were down-regulated (at the second biopsy) within the cycle. Strikingly, all of the marker molecules investigated showed negative or weak and inadequate expression in the mid-secretory phase. Numbers of LGLs remained as low as in the proliferative phase. In contrast, fertile patients were found to express these marker molecules distinctly in the mid-secretory phase.

CONCLUSIONS

It may be hypothesized that a severe deficiency of these angiogenesis-related marker molecules leads to defective development of the endometrium, which remains thin. Deficient angiogenetic development may thus provide an explanation for the endometrial factor that causes infertility. Further investigations will need to focus on identifying the regulating factors that act between steroid receptor activation and the expression of these marker molecules.

Prostaglandin E2 promotes BeWo spheroids implantation in RL95-2 cell monolayers

PURPOSE

Integrin αvβ3 (ITG αvβ3) participates in the process of implantation between the embryo and the endometrium. This study investigated the effects of prostaglandin E₂ (PGE₂) on endometrial receptivity and implantation efficiency of the embryo, and their possible mechanisms.

METHODS

Quantitative real-time reverse transcription PCR (qRT-PCR) and western blotting were used to detect the changes in mRNA and protein levels of ITG αvβ3 in RL95-2 cells after administering PGE₂. BeWo trophoblast cells and RL95-2 endometrial epithelial cells were used to establish an in vitro model, which was used to observe the adhesion rate and spreading efficiency between BeWo spheroids and RL95-2 cell monolayers after pretreatment with different concentrations of PGE₂.

RESULTS

PGE₂ at 200 nM increased the mRNA and protein levels of ITG αv significantly (p < 0.05); 100 nM PGE₂ increased the mRNA and protein levels of ITG β3 significantly (p < 0.05). PGE₂ at 200 nM increased significantly the adhesion and spreading efficiency of BeWo spheres to RL95-2 cell monolayers.

CONCLUSIONS

An appropriate concentration of PGE₂ might increase the expression of ITG αvβ3, which would, promote embryo adhesion and spreading efficiency. This study provides further evidence that increased expression of ITG αvβ3 might promote implantation by improving endometrial receptivity.

A phytoestrogen supplement prevents the altered gene expression associated with pregnancy implantation induced by IL-1β in endometrial epithelial cells

Phytoestrogens stimulate expression of the uterine estrogen receptor and regulate uterine functions in reproductive tissues. However, comprehensive understanding of the beneficial impacts of phytoestrogens on uterine biology at the molecular level remains unexplored. Interleukin-1β (IL-1β) expression is increased in the inflamed decidua and is associated with first trimester pregnancy loss. AglyMax-Sup has the same composition as that of the phytoestrogen supplement AglyMax but with added vitamins and other components. Expression of genes associated with implantation may be enhanced by AglyMax-Sup compared with AglyMax. We tested the hypothesis that AglyMax-Sup has greater effects on implantation compared with AglyMax, using RT-PCR and Western blotting in the endometrial epithelial cell line. Furthermore, we investigated the protective effect of AglyMax-Sup on IL-1βinduced changes in estrogen-responsive gene expression in endometrial epithelial cells. The purpose of this study was to compare the effects of the phytoestrogen supplement AglyMax-Sup with those of AglyMax on estrogen-responsive gene expression. AglyMax and AglyMax-Sup significantly (p<0.05) induced gene expression of glycodelin-A, HoxA10, IL-11, LIF, MEG-E8 and TGFβ1. AglyMax-Sup induced high levels of these genes compared with the levels induced by AglyMax. The enhanced expression of LIF, IL-11, integrin αV, and HOXA10 induced by AglyMax-Sup was abolished by the ER antagonist fulvestrant and the ERK inhibitor PD98059. Meanwhile, IL-1β inhibited progesterone plus estrogen-induced TGFβ1, glycodelin-A, HOXA10, and integrin αV expression. IL-1β-induced suppression of these expression was reversed by AglyMax-Sup. These results indicate that expression of genes associated with implantation may be increased by AglyMax-Sup compared with AglyMax. AglyMax-Sup might abrogate IL-1β-mediated changes that can affect embryo implantation via the MAPK pathway.

Transcriptional Dynamics of Cultured Human Villous Cytotrophoblasts

During human pregnancy, cytotrophoblasts (CTBs) play key roles in uterine invasion, vascular remodeling, and anchoring of the feto-placental unit. Due to the challenges associated with studying human placentation in utero, cultured primary villous CTBs are used as a model of the differentiation pathway that leads to invasion of the uterine wall. In vitro, CTBs emulate in vivo cell behaviors, such as migration, aggregation, and substrate penetration. Although some of the molecular features related to these cell behaviors have been described, the underlying mechanisms, at a global level, remain undefined at midgestation. Thus, in this study, we characterized second-trimester CTB differentiation/invasion in vitro, correlating the major morphological transitions with the transcriptional changes that occurred at these steps. After plating on Matrigel as individual cells, CTBs migrated toward each other and formed multicellular aggregates. In parallel, using a microarray approach, we observed differentially expressed (DE) genes across time, which were enriched for numerous functions, including cell migration, vascular remodeling, morphogenesis, cell communication, and inflammatory signaling. DE genes encoded several molecules that we and others previously linked to critical CTB function in vivo, suggesting that the novel DE molecules we discovered played important roles. Immunolocalization confirmed that CTBs in situ gave a signal for two of the most highly expressed genes in vitro. In summary, we characterized, at a global level, the temporal dynamics of primary human CTB gene expression in culture. These data will enable future analyses of various types of in vitro perturbations-for example, modeling disease processes and environmental exposures.

Should studies on Glanzmann thrombasthenia not be telling us more about cardiovascular disease and other major illnesses?

Glanzmann thrombasthenia (GT) is a rare inherited bleeding disorder caused by loss of αIIbβ3 integrin function in platelets. Most genetic variants of β3 also affect the widely expressed αvβ3 integrin. With brief mention of mouse models, I now look at the consequences of disease-causing ITGA2B and ITGB3 mutations on the non-hemostatic functions of platelets and other cells. Reports of arterial thrombosis in GT patients are rare, but other aspects of cardiovascular disease do occur including deep vein thrombosis and congenital heart defects. Thrombophilic and other risk factors for thrombosis and lessons from heterozygotes and variant forms of GT are discussed. Assessed for GT patients are reports of leukemia and cancer, loss of fertility, bone pathology, inflammation and wound repair, infections, kidney disease, autism and respiratory disease. This survey shows an urgent need for a concerted international effort to better determine how loss of αIIbβ3 and αvβ3 influences health and disease.

Water-extracted Perilla frutescens increases endometrial receptivity though leukemia inhibitory factor-dependent expression of integrins

The leaves and stems of Perilla frutescens var. acuta Kudo (PF) have been used to prevent threatened abortion in traditional medicine in the East Asian countries. Because reduced receptivity of endometrium is a cause of abortion, we analyzed the action of PF on the endometrial receptivity. PF increased the level of leukemia inhibitory factor (LIF), a major cytokine regulating endometrial receptivity, and LIF receptor in human endometrial Ishikawa cells. The PF-induced LIF expression was mediated by c-jun N-terminal kinase (JNK) and p38 pathways. Adhesion between Ishikawa cells and trophoblastic JAr cells stimulated by PF treatment was abolished by knock down of LIF expression or antagonism of LIFR. In addition, the expressions of integrin β3 and β5 were increased by PF treatment in Ishikawa cells. The PF-induced expression of integrin β3 and β5 was reduced with an LIFR antagonist. Neutralization of both integrins successfully blocked PF-stimulated adhesion of JAr cells and Ishikawa cells. These results suggest that PF enhanced the adhesion between Ishikawa cells and JAr cells by increasing the expression of integrin β3 and β5 via an LIF-dependent pathway. Given the importance of endometrial receptivity in successful pregnancy, PF can be a novel and effective candidate for improving pregnancy rate.