Effects of E-cadherin on mouse embryo implantation and expression of matrix metalloproteinase-2 and -9

Uncovering the role of TET2-mediated ENPEP activation in trophoblast cell fate determination

Early trophoblast differentiation is crucial for embryo implantation, placentation and fetal development. Dynamic changes in DNA methylation occur during preimplantation development and are critical for cell fate determination. However, the underlying regulatory mechanism remains unclear. Recently, we derived morula-like expanded potential stem cells from human preimplantation embryos (hEPSC-em), providing a valuable tool for studying early trophoblast differentiation. Data analysis on published datasets showed differential expressions of DNA methylation enzymes during early trophoblast differentiation in human embryos and hEPSC-em derived trophoblastic spheroids. We demonstrated downregulation of DNA methyltransferase 3 members (DNMT3s) and upregulation of ten-eleven translocation methylcytosine dioxygenases (TETs) during trophoblast differentiation. While DNMT inhibitor promoted trophoblast differentiation, TET inhibitor hindered the process and reduced implantation potential of trophoblastic spheroids. Further integrative analysis identified that glutamyl aminopeptidase (ENPEP), a trophectoderm progenitor marker, was hypomethylated and highly expressed in trophoblast lineages. Concordantly, progressive loss of DNA methylation in ENPEP promoter and increased ENPEP expression were detected in trophoblast differentiation. Knockout of ENPEP in hEPSC-em compromised trophoblast differentiation potency, reduced adhesion and invasion of trophoblastic spheroids, and impeded trophoblastic stem cell (TSC) derivation. Importantly, TET2 was involved in the loss of DNA methylation and activation of ENPEP expression during trophoblast differentiation. TET2-null hEPSC-em failed to produce TSC properly. Collectively, our results illustrated the crucial roles of ENPEP and TET2 in trophoblast fate commitments and the unprecedented TET2-mediated loss of DNA methylation in ENPEP promoter.

Endometrial Inflammation and Impaired Spontaneous Decidualization: Insights into the Pathogenesis of Adenomyosis

Adenomyosis is an estrogen-dependent gynecologic disease characterized by the myometrial invasion of the endometrial tissue. This review summarized the current understanding and recent findings on the pathophysiology of adenomyosis, focusing on repeated menstruation, persistent inflammation, and impaired spontaneous decidualization. A literature search was performed in the PubMed and Google Scholar databases from inception to 30 April 2022. Thirty-one full-text articles met the eligibility criteria. Repeated episodes of physiological events (i.e., endometrial shedding, damage, proliferation, differentiation, repair, and regeneration) during the menstrual cycle are associated with inflammation, angiogenesis, and immune processes. The decidualization process in humans is driven by the rise in progesterone levels, independently of pregnancy (i.e., spontaneous decidualization). Adenomyotic cells produce angiogenic and fibrogenic factors with the downregulation of decidualization-associated molecules. This decidualization dysfunction and persistent inflammation are closely related to the pathogenesis of adenomyosis. Recently, it has been found that the reproductive tract microbiota composition and function in women with adenomyosis differ from those without. An increase in opportunistic pathogens and a decrease in beneficial commensals may promote impaired defense mechanisms against inflammation and predispose women to uncontrolled endometrial inflammation. However, currently, there is no direct evidence that adenomyosis is linked to pre-existing inflammation and impaired spontaneous decidualization. Overall, persistent inflammation, impaired spontaneous decidualization, and microbiota dysbiosis (i.e., an imbalance in the composition and function of endometrial microbiota) may be involved in the pathophysiology of adenomyosis.

The miR-182-5p/NDRG1 Axis Controls Endometrial Receptivity through the NF-κB/ZEB1/E-Cadherin Pathway

Endometrial receptivity is essential for successful pregnancy, and its impairment is a major cause of embryo-implantation failure. MicroRNAs (miRNAs) that regulate epigenetic modifications have been associated with endometrial receptivity. However, the molecular mechanisms whereby miRNAs regulate endometrial receptivity remain unclear. Therefore, we investigated whether miR-182 and its potential targets influence trophoblast cell attachment. miR-182 was expressed at lower levels in the secretory phase than in the proliferative phase of endometrium tissues from fertile donors. However, miR-182 expression was upregulated during the secretory phase in infertile women. Transfecting a synthetic miR-182-5p mimic decreased spheroid attachment of human JAr choriocarcinoma cells and E-cadherin expression (which is important for endometrial receptivity). miR-182-5p also downregulated N-Myc downstream regulated 1 (NDRG1), which was studied further. NDRG1 was upregulated in the secretory phase of the endometrium tissues and induced E-cadherin expression through the nuclear factor-κΒ (NF-κΒ)/zinc finger E-box binding homeobox 1 (ZEB1) signaling pathway. NDRG1-overexpressing or -depleted cells showed altered attachment rates of JAr spheroids. Collectively, our findings indicate that miR-182-5p-mediated NDRG1 downregulation impaired embryo implantation by upregulating the NF-κΒ/ZEB1/E-cadherin pathway. Hence, miR-182-5p is a potential biomarker for negative selection in endometrial receptivity and a therapeutic target for successful embryo implantation.

Association of MMP2 and MMP9 gene polymorphisms with the recurrent spontaneous abortion: A meta-analysis

BACKGROUND

Recurrent spontaneous abortion (RSA) accounts for the most common complication of early pregnancy in humans. Matrix metalloproteinases (MMPs) play important regulatory roles in implantation and placentation to ensure a successful pregnancy. Single nucleotide polymorphisms (SNPs) have been identified in the promoters of MMP2 and MMP9 genes. However, the associations between MMP2 and MMP9 SNPs and the RSA risk remain unclear. The aim of this meta-analysis was to investigate whether MMP2 (-735C>T) and MMP9 (-1562C>T) SNPs are associated with the risk of RSA.

METHODS

Literatures published before 17th April 2020 were screened to identify the eligible studies. Heterogeneity, sensitivity and publication bias analysis were analyzed by the STATA software. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by the Review Manager software with fixed effects model.

RESULTS

After screening, 2 studies for MMP2 (-735C>T) (278 RSA cases and 265 controls) and 4 studies for MMP9 (-1562C>T) (520 RSA cases and 512 controls) were enrolled in this meta-analysis. Results showed that MMP2 (-735C>T) presented a statistically significant association with the risk of RSA under allelic (T vs C: OR = 1.50, 95% CI = 1.14-1.98, P = 0.004, I² = 31%), heterozygote (CT vs CC: OR = 1.74, 95% CI = 1.22-2.50, P = 0.003, I² = 41%) and dominant (TT + CT vs CC: OR = 1.74, 95% CI = 1.23-2.45, P = 0.002, I² = 40%) genetic models. MMP9 (-1562C>T) in allelic (T vs C: OR = 1.34, 95% CI = 1.08-1.65, P = 0.007, I² = 0%), heterozygote (CT vs CC: OR = 1.38, 95% CI = 1.06-1.79, P = 0.02, I² = 0%) and dominant (TT + CT vs CC: OR = 1.41, 95% CI = 1.10-1.82, P = 0.008, I² = 0%) genetic models were significantly correlated with the RSA risk.

CONCLUSIONS

Our meta-analysis results suggest that MMP2 -735T allele and MMP9 -1562T allele have significant association with the risk of RSA.

Long non-coding RNA KCNQ1OT1 up-regulates CTNND1 by sponging miR-329-3p to induce the proliferation, migration, invasion, and inhibit apoptosis of colorectal cancer cells

Background

Long non-coding RNAs (lncRNAs) have been certified to be involved in the occurrence and growth of diverse cancers, including CRC. The purpose of the research was to explore the effects of lncRNA KCNQ1 overlapping transcript 1 (KCNQ1OT1) on proliferation, migration, invasion, and apoptosis in CRC cells and its mechanism.

Methods

The levels of KCNQ1OT1 and miR-329-3p were examined by quantitative real-time polymerase chain reaction (qRT-PCR) in CRC tissues and cells. The mRNA and protein levels of catenin delta-1 (CTNND1) were measured by qRT-PCR and western blot analysis, respectively. The targets of KCNQ1OT1 and miR-329-3p were predicted by online software and confirmed by luciferase reporter assay. The cell proliferation, migration, invasion, and apoptosis were examined using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), transwell, and apoptosis assay. The expression levels of CyclinD1, Bcl-2, MMP9, Cleaved-casp-3, and E-cadherin in SW480 and LS1034 cells were gauged by western blot analysis. Xenograft tumor model was structured to prove the biological role of KCNQ1OT1 of CRC in vivo.

Results

The levels of KCNQ1OT1 and CTNND1 were significantly increased in CRC tissues and cells. Knockdown of KCNQ1OT1 suppressed proliferation, migration, invasion, and induced apoptosis in CRC cells. Conversely, CTNND1 overexpression reversed the impact of KCNQ1OT1 knockdown on CRC cells. Moreover, CTNND1 was verified as a direct target of miR-329-3p, and miR-329-3p could specially bind to KCNQ1OT1. Also, the down-regulation of KCNQ1OT1 triggered the CRC progress by up-regulating CTNND1 expression in CRC cells. Besides, KCNQ1OT1 knockdown inhibited CRC tumor growth through the miR-329-3p/CTNND1 axis in vivo.

Conclusion

Our results indicated that KCNQ1OT1 could positively regulate CTNND1 expression by sponging miR-329-3p, thereby boosting the progression of CRC. Our findings provided the underlying therapy targets for CRC.

LPS-treatment of bovine endometrial epithelial cells causes differential DNA methylation of genes associated with inflammation and endometrial function

Background

Lipopolysaccharide (LPS) endotoxin stimulates pro-inflammatory pathways and is a key player in the pathological mechanisms involved in the development of endometritis. This study aimed to investigate LPS-induced DNA methylation changes in bovine endometrial epithelial cells (bEECs), which may affect endometrial function. Following in vitro culture, bEECs from three cows were either untreated (0) or exposed to 2 and 8 μg/mL LPS for 24 h.

Results

DNA samples extracted at 0 h and 24 h were sequenced using reduced representation bisulfite sequencing (RRBS). When comparing DNA methylation results at 24 h to time 0 h, a larger proportion of hypomethylated regions were identified in the LPS-treated groups, whereas the trend was opposite in controls. When comparing LPS groups to controls at 24 h, a total of 1291 differentially methylated regions (DMRs) were identified (55% hypomethylated and 45% hypermethylated). Integration of DNA methylation data obtained here with our previously published gene expression data obtained from the same samples showed a negative correlation (r = − 0.41 for gene promoter, r = − 0.22 for gene body regions, p < 0.05). Differential methylation analysis revealed that effects of LPS treatment were associated with methylation changes for genes involved in regulation of immune and inflammatory responses, cell adhesion, and external stimuli. Gene ontology and pathway analyses showed that most of the differentially methylated genes (DMGs) were associated with cell proliferation and apoptotic processes; and pathways such as calcium-, oxytocin- and MAPK-signaling pathways with recognized roles in innate immunity. Several DMGs were related to systemic inflammation and tissue re-modelling including HDAC4, IRAK1, AKT1, MAP3K6, Wnt7A and ADAMTS17.

Conclusions

The present results show that LPS altered the DNA methylation patterns of bovine endometrial epithelial cells. This information, combined with our previously reported changes in gene expression related to endometrial function, confirm that LPS activates pro-inflammatory mechanisms leading to perturbed immune balance and cell adhesion processes in the endometrium.

Potential roles of metalloproteinases of endometrium-derived exosomes in embryo-maternal crosstalk during implantation

During embryo implantation, crosstalk between the endometrial epithelium and the blastocyst, especially the trophoblasts, is a prerequisite for successful implantation. During this crosstalk, various molecular and functional changes occur to promote synchrony between the embryo and the endometrium as well as the uterine cavity microenvironment. In the past few years, growing evidence has shown that endometrium-derived exosomes play pivotal roles in the embryonic-maternal crosstalk during implantation, although the exact mechanism of this crosstalk has yet to be determined. The presence of metalloproteinases has been reported in endometrium-derived exosomes, implying the importance of these enzymes in exosome-based crosstalk. Thus, in this review, we describe the potential roles of the metalloproteinases of endometrium-derived exosomes in promoting embryo attachment and implantation. This study could provide a better understanding of the potential roles of exosomal metalloproteinases in embryo implantation and pave the way for developing novel exosome-based regulatory agents to support early pregnancy.

Effect of beta-cypermethrin exposure on embryo implantation in mice

The aim of this study was to investigate the effect of β-CP on embryo implantation in mice. Forty female mice were randomly assigned to four groups of 10 mice each: one control group and three β-CP treated groups. The control group was administered corn oil only, while the three β-CP-treated groups were given corn oil containing 5, 10, and 20 mg/kg bw d β-CP for 3 months through intragastric administration. The results indicated that the administration of β-CP decreased the rate of embryo implantation (all p < 0.05), E₂ level in the serum, and the expression of Homeobox A10 (HoxA10) protein. In addition, β-CP significantly increased ERa and PRA protein expression levels. These results suggest that β-CP can disrupt the balance of E₂ and P, influence ERa and PRA expression and their downstream-related molecule Hoxa10, and decrease embryo implantation.

Mice endometrium receptivity in early pregnancy is impaired by maternal hyperinsulinemia

Previous studies have investigated the lower embryo implantation rates in women with polycystic ovary syndrome, obesity and type 2 diabetes, and specifically the association between the abnormal oocyte and embryo and hyperinsulinemia. The importance of hyperinsulinemia on maternal endometrium receptivity remains to be elucidated. The present study used a hyperinsulinemic mouse model to determine whether hyperinsulinemia may affect endometrial receptivity. An insulin intervention mouse model was first established. The serum levels of insulin, progesterone and estradiol were subsequently detected by ELISA assay analysis. The number of implantation sites was recorded using Trypan blue dye and the morphology of mice uteri was investigated using hematoxylin and eosin staining. The expression levels of molecular markers associated with endometrial receptivity were detected by reverse transcription‑quantitative polymerase chain reaction, western blotting and immunohistochemistry analyses. Finally, the importance of mechanistic target of rapamycin (mTOR) expression following insulin treatment was determined. Mice treated with insulin developed insulin resistance and hyperinsulinemia. The number of implantation sites following insulin treatment did not differ between the control and insulin‑treated groups. Additionally, no significant morphological alterations in mice uteri between control and insulin‑treated groups were observed. However, the expression levels of estrogen receptor (Esr) 1, Esr2, progesterone receptor and homeobox A10 associated with endometrial receptivity, were imbalanced during endometrium receptivity when maternal hyperinsulinemia was induced. Western blot analysis revealed that expression levels of endometrial phosphorylated (p)‑mTOR and p‑ribosomal protein S6 kinase β‑1 were significantly greater in the insulin‑treated group. These results demonstrated that although an embryo may implant into endometrium, mice endometrium receptivity in early pregnancy may be impaired by maternal hyperinsulinemia. In addition, mTOR signaling may be involved in this process. The present study provides preliminary results demonstrating that female reproduction may be compromised during hyperinsulinemia, which requires further investigation in future studies.

Basement membrane fragments in the context of the epithelial-to-mesenchymal transition

The epithelial-to-mesenchymal transition (EMT) enables cells of epithelial phenotype to become motile and change to a migratory mesenchymal phenotype. EMT is known to be a fundamental requisite for tissue morphogenesis, and EMT-related pathways have been described in cancer metastasis and tissue fibrosis. Epithelial structures are marked by the presence of a sheet-like extracellular matrix, the basement membrane, which is assembled from two major proteins, laminin and collagen type IV. This specialized matrix is essential for tissue function and integrity, and provides an important barrier to the potential pathogenic migration of cells. The profound phenotypic transition in EMT involves the epithelial cells disrupting the basement membrane. Matrix metalloproteinases (MMPs) are known to cleave components of basement membranes, but MMP-basement membrane crosstalk during EMT in vivo is poorly understood. However, MMPs have been reported to play a role in EMT-related processes and a variety of basement membrane fragments have been shown to be released by specific MMPs in vitro and in vivo exhibiting distinct biological activities. This review discusses general considerations regarding the basement membrane in the context of EMT, a possible role for specific MMPs in EMT and highlights biologically active basement membrane fragments liberated by MMPs.

Sophoricoside fails the embryo implantation by compromising the uterine endometrial receptivity at implantation "window" of pregnant mice

Sophoricoside (SOPH) is an isoflavone glycoside isolated from the fruits of Sophora japonica. Since its first isolation in 1961, there are rare findings about the effects of SOPH on reproductive system. In the present study, the pregnant mice administrated by different doses of SOPH were used to explore the effect of SOPH on embryo implantation, especially on the endometrial receptivity. The statistical results showed that the number of implanted embryos was gradually declining along the increasing dose of SOPH. When the administrated dose of SOPH was 600 mg/kg per day, great changes were observed in the exposed uterine morphology and up-regulated progesterone receptor (PR) and down-regulated estrogen receptor α (ERα), E-cadherin, matrix metalloproteinase-2 (MMP-2) and integrin β3 were also found in SOPH-exposed uterine. These findings demonstrated that SOPH exposure reduced the number of implanted embryos in a dose-dependent manner and failed the embryo implantation through altering the morphology of uterine and compromising the endometrial receptivity.

Biologically-active laminin-111 fragment that modulates the epithelial-to-mesenchymal transition in embryonic stem cells

The dynamic interplay between the extracellular matrix and embryonic stem cells (ESCs) constitutes one of the key steps in understanding stem cell differentiation in vitro. Here we report a biologically-active laminin-111 fragment generated by matrix metalloproteinase 2 (MMP2) processing, which is highly up-regulated during differentiation. We show that the β1-chain-derived fragment interacts via α3β1-integrins, thereby triggering the down-regulation of MMP2 in mouse and human ESCs. Additionally, the expression of MMP9 and E-cadherin is up-regulated in mouse ESCs--key players in the epithelial-to-mesenchymal transition. We also demonstrate that the fragment acts through the α3β1-integrin/extracellular matrix metalloproteinase inducer complex. This study reveals a previously unidentified role of laminin-111 in early stem cell differentiation that goes far beyond basement membrane assembly and a mechanism by which an MMP2-cleaved laminin fragment regulates the expression of E-cadherin, MMP2, and MMP9.

Matrix metalloproteinases 2 and 9 and e-cadherin expression in the endometrium during the implantation window of infertile women before in vitro fertilization treatment

OBJECTIVE

To evaluate the expression of endometrial matrix metalloproteinases (MMPs) 2 and 9 and E-cadherin in peri-implantation phase of infertile women who have undergone in vitro fertilization (IVF) cycles.

METHODS

This prospective study included 51 patients who underwent endometrial biopsy during the receptive phase in a menstrual cycle prior to IVF treatment. The samples were evaluated by tissue microarray for immunohistochemical study.

RESULTS

The expression of MMP-2, MMP-9, and E-cadherin in the endometrium prior to IVF treatment was not associated with pregnancy. There was a decrease in E-cadherin immunodetection, the higher the age of the patients, a negative relationship between E-cadherin and MMP-2, and a positive association between MMP-9 and E-cadherin.

CONCLUSIONS

The MMP-2, MMP-9, and E-cadherin are expressed in the endometrium of infertile patients during the receptive phase of the natural menstrual cycle. However, there is no correlation between the expression of these molecules and the clinical IVF outcomes.

Successful implantation after reducing matrix metalloproteinase activity in the uterine cavity

BACKGROUND

Recently, the concept of recurrent implantation failure (RIF) in assisted reproductive technology has been enlarged. Chronic uterine inflammation is a known cause of implantation failure and is associated with high matrix metalloproteinase (MMP) activity in uterine cavity flushing. MMP activity of women with RIF has been reported to be higher than that of fertile women. In the present retrospective study we evaluated the efficacy of treatment for high MMP activity in the uterine cavity of patients with RIF.

METHODS

Of the 597 patients recruited to the study, 360 patients underwent MMP measurements and 237 patients did not (control group). All patients had failed to become pregnant, despite at least two transfers of good-quality embryos. Gelatinase MMP-2 and MMP-9 activity in uterine flushing fluid was detected by enzymology (MMP test). All samples were classified into two groups (positive or negative) based on the intensity of the bands on the enzyme zymogram, which represents the degree of MMP activity. Patients who tested positive on the initial test were treated for 2 weeks with a quinolone antibiotic and a corticosteroid, and subsequently underwent a second MMP test. Negative results on the second MMP tests after treatment and subsequent rates of pregnancy and miscarriage were used to evaluate the efficacy of treatment. Data were analyzed by the Mann-Whitney U-test and the chi-square test.

RESULTS

Of the patients who underwent the MMP test, 15.6% had positive results (high MMP activity). After treatment, 89.3% of patients had negative results on the second MMP test. These patients had a significantly better pregnancy rate (42.0%) than the control group (26.6%), as well as a lower miscarriage rate (28.5% vs 36.5%, respectively).

CONCLUSIONS

A 2-week course of antibiotics and corticosteroids effectively improves the uterine environment underlying RIF by reducing MMP activity.

Effects of DEHP on endometrial receptivity and embryo implantation in pregnant mice

Di-(2-ethylhexyl)-phthalate (DEHP) is a ubiquitous environmental pollutant and endocrine disruptor (ED) that causes serious adverse effects on animal and human health. The harmful effects of DEHP on human reproduction are increasingly recognized, especially in women. However, it is not known how endometrial receptivity and embryo implantation, which play important roles in the establishment of pregnancy, are affected by DEHP. This study was aimed towards investigating the effects of DEHP on endometrial receptivity and embryo implantation in pregnant mice. The pregnant mice received DEHP at 0, 250, 500 and 1000 mg/kg/day from day 1 (D1) of gestation until sacrifice. Administration of DEHP led to compromised endometrial receptivity and decreased number of implantation sites. The mRNA and protein expression levels of ERα, PR and E-cadherin, but not those of HoxA10 and MMP-2, were up-regulated by DEHP in the mouse endometrium. The results further suggested that DEHP disrupts the MAPK and NF-κB signaling pathways. This was maybe one of paths which influenced the E-cadherin expression. In conclusion, DEHP reduced endometrial receptivity and impaired embryo implantation by influencing the expression of hormone receptors and E-cadherin. Therefore, determining the full extent of the hazards of DEHP to human reproduction will be vital to developing and implementing effective protective measures.

Adherens junction proteins in the hamster uterus: their contributions to the success of implantation

The adherens junction (AJ) is important for maintaining uterine structural integrity, composition of the luminal environment, and initiation of implantation by virtue of its properties of cell-cell recognition, adhesion, and establishment of cell polarity and permeability barriers. In this study, we investigated the uterine changes of AJ components E-cadherin, beta-catenin, and alpha-catenin at their mRNA and protein levels, together with the cellular distribution of meprinbeta, phospho-beta-catenin, and active beta-catenin proteins, in hamsters that show only ovarian progesterone-dependent uterine receptivity and implantation. By in situ hybridization and immunofluorescence, we have demonstrated that uterine epithelial cells expressed three of these AJ proteins and their mRNAs prior to and during the initial phase of implantation. Immunofluorescence study showed no change in epithelial expression patterns of uterine AJ proteins from Days 1 to 5 of pregnancy. With advancement of the implantation process, AJ components were primarily expressed in cells of the secondary decidual zone (SDZ), but not in the primary decidual zone (PDZ). In contrast, we noted strong expression of beta-catenin and alpha-catenin proteins in the PDZ, but not in the SDZ, of mice. Taken together, these results suggest that AJ proteins contribute to uterine barrier functions by cell-cell adhesion to ensure protection of the embryo. In addition, cleavage of E-cadherin by meprinbeta might contribute to weakening uterine epithelial cell-cell contact for blastocyst implantation. We also report that the nuclear localization of active beta-catenin from Day 4 onward in hamsters implies that beta-catenin/Wnt-signal transduction is activated in the uterus during implantation and decidualization.

Expression and hormonal regulation of E-cadherin in canine uterus during early pregnancy

E-cadherin, a Ca(2+)-dependent cell adhesion molecule, is necessary for endometrial receptivity to blastocyst implantation. The aim of this study was to investigate the differential expression of E-cadherin in canine uterus during early pregnancy and its regulation under different conditions by in situ hybridization. E-cadherin mRNA expression was at a low level in the glandular epithelium on days 6, 12 and 17 of pregnancy. On days 20 and 23 of pregnancy, E-cadherin mRNA was highly expressed in the glandular epithelium surrounding the embryo, but not in the luminal epithelium and declined in villi and placenta on day 28 of pregnancy. During oestrous cycle, a moderate level of E-cadherin mRNA expression was found in the luminal and glandular epithelium of canine uteri at oestrus stage. The same expression was also found at anoestrus stage. Progesterone slightly induced the expression of E-cadherin mRNA in the luminal and glandular epithelium of ovariectomized canine uterus. These results suggest that E-cadherin expression is closely related to canine implantation and can be up-regulated by progesterone.

Cytokine regulation during the formation of the fetal-maternal interface: focus on cell-cell adhesion and remodelling of the extra-cellular matrix

The establishment of human pregnancy requires the orchestration of substantial cell differentiation and tissue remodelling processes in the context of a complex dialogue between the receptive endometrium and the implanting blastocyst, and is therefore dependent upon a complex sequence of signalling events. Cytokines play an important role in each step of implantation, modulating expression of adhesion molecules on both the fetal and maternal surfaces, regulating expression of the proteases that remodel the extra-cellular matrix, and promoting invasion and differentiation of trophoblasts. Here we review the role of cytokines in regulating the establishment of the fetal-maternal interface, with a particular focus on regulation of the functional expression of CAMs, the ECM and of the proteinases that modulate their function.

Effects of activin A on the in vitro development and mRNA expression of bovine embryos cultured in chemically-defined two-step culture medium

The purpose of the present study was to evaluate the effects of activin A on the developmental competence of in vitro fertilized (IVF) bovine embryos derived from a two-step defined culture system (C1/C2 medium) during the early or later stages of embryo development. To evaluate the effects of activin A on transcriptional levels, we analysed genes related to blastocyst hatching and implantation and to activin signalling pathway in IVF embryos. Cumulus-oocyte complexes were matured for 22 h and fertilized in vitro. Presumptive zygotes were cultured in the presence or absence of activin A during early (0-120 h, C1) or later (120-192 h, C2) stages. Although the developmental competence of embryos cultured with activin A in C1 medium was not significantly different from their corresponding controls, development to blastocysts (22.4% vs 34.7%; p < 0.05) and the blastocyst hatching rate (9.3% vs 22.4%; p < 0.05) in C2 medium supplemented with 100 ng/ml activin A were significantly higher than in the control group. To evaluate the effect of activin A on transcription, the relative expression levels of genes related to blastocyst hatching and implantation (Na/K-ATPase, E-cad and Glut-1) as well as activin signalling pathway (ActRII, ActRIIB and Smad2) were analysed. Compared to control medium, gene expression of Na/K-ATPase, E-cad, Glut-1, ActRII and ActRIIB was increased in medium supplemented with activin A. In conclusion, this study suggests that activin A, during the later stage of in vitro bovine embryo development, can enhance in vitro development of embryos by increasing hatching rates and affecting expression levels of genes related to hatching and implantation in defined culture medium.