Longitudinal profiling of human androgenotes through single-cell analysis unveils paternal gene expression dynamics in early embryo development

STUDY QUESTION

How do transcriptomics vary in haploid human androgenote embryos at single cell level in the first four cell cycles of embryo development?

SUMMARY ANSWER

Gene expression peaks at the fourth cell cycle, however some androcytes exhibit unique transcriptional behaviors.

WHAT IS KNOWN ALREADY

The developmental potential of an embryo is determined by the competence of the oocyte and the sperm. However, studies of the contribution of the paternal genome using pure haploid androgenotes are very scarce.

STUDY DESIGN, SIZE, DURATION

This study was performed analyzing the single-cell transcriptomic sequencing of 38 androcytes obtained from 10 androgenote bioconstructs previously produced in vitro (de Castro et al., 2023). These results were analyzed through different bioinformatics software such as g: Profiler, GSEA, Cytoscape, and Reactome.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Single cell sequencing was used to obtain the transcriptomic profiles of the different androcytes. The results obtained were compared between the different cycles studied using the DESeq2 program and functional enrichment pathways using g: Profiler, Cytoscape, and Reactome.

MAIN RESULTS AND THE ROLE OF CHANCE

A wave of paternally driven transcriptomic activation was found during the third-cell cycle, with 1128 upregulated and 225 downregulated genes and the fourth-cell cycle, with 1373 upregulated and 286 downregulated genes, compared to first-cell cycle androcytes. Differentially expressed routes related to cell differentiation, DNA-binding transcription, RNA biosynthesis and RNA polymerase II transcription regulatory complex, and cell death were found in the third and fourth with respect to the first-cell cycle. Conversely, in the fourth cell cycle, 153 downregulated and 332 upregulated genes were found compared with third cell cycle, associated with differentially expressed processes related to E-box binding and zinc finger protein 652 (ZNF652) transcription factor. Further, significant overexpression of LEUTX, PRAMEF1, DUXA, RFPL4A, TRIM43, and ZNF675 found in androgenotes, compared to biparental embryos, highlights the paternal contributions to zygote genome activation.

LARGE SCALE DATA

All raw sequencing data are available through the Gene Expression Omnibus (GEO) under accessions number: GSE216501.

LIMITATIONS, REASONS FOR CAUTION

Extrapolation of biological events from uniparental constructs to biparental embryos should be done with caution. Maternal and paternal genomes do not act independently of each other in a natural condition. The absence of one genome may affect gene transcription of the other. In this sense, the haploid condition of the bioconstructs could mask the transcriptomic patterns of the single cells.

WIDER IMPLICATIONS OF THE FINDINGS

The results obtained demonstrated the level of involvement of the human paternal haploid genome in the early stages of embryo development as well as its evolution at the transcriptomic level, laying the groundwork for the use of these bioconstructs as reliable models to dispel doubts about the genetic role played by the paternal genome in the early cycles of embryo development.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by Instituto de Salud Carlos III (ISCIII) through the project 'PI22/00924', co-funded by European Regional Development Fund (ERDF); 'A way to make Europe'. F.D. was supported by the Spanish Ministry of Economy and Competitiveness through the Miguel Servet program (CPII018/00002). M.J.E. was supported by Instituto de Salud Carlos III (PI19/00577 [M.J.E.]) and FI20/00086. P.dC. was supported by a predoctoral grant for training in research into health (PFIS PI19/00577) from the Instituto de Salud Carlos III. All authors declare having no conflict of interest with regard to this trial.

Mosaic results after preimplantation genetic testing for aneuploidy may be accompanied by changes in global gene expression

Aneuploidy in preimplantation embryos is a major cause of human reproductive failure. Unlike uniformly aneuploid embryos, embryos diagnosed as diploid-aneuploid mosaics after preimplantation genetic testing for aneuploidy (PGT-A) can develop into healthy infants. However, the reason why these embryos achieve full reproductive competence needs further research. Current RNA sequencing techniques allow for the investigation of the human preimplantation transcriptome, providing new insights into the molecular mechanisms of embryo development. In this prospective study, using euploid embryo gene expression as a control, we compared the transcriptome profiles of inner cell mass and trophectoderm samples from blastocysts with different levels of chromosomal mosaicism. A total of 25 samples were analyzed from 14 blastocysts with previous PGT-A diagnosis, including five low-level mosaic embryos and four high-level mosaic embryos. Global gene expression profiles visualized in cluster heatmaps were correlated with the original PGT-A diagnosis. In addition, gene expression distance based on the number of differentially expressed genes increased with the mosaic level, compared to euploid controls. Pathways involving apoptosis, mitosis, protein degradation, metabolism, and mitochondrial energy production were among the most deregulated within mosaic embryos. Retrospective analysis of the duration of blastomere cell cycles in mosaic embryos revealed several mitotic delays compared to euploid controls, providing additional evidence of the mosaic status. Overall, these findings suggest that embryos with mosaic results are not simply a misdiagnosis by-product, but may also have a genuine molecular identity that is compatible with their reproductive potential.

P-670 Phytoestrogen concentration in women’s urine and follicular fluid are associated with better IVF outcomes in euploid single embryo transfer cycles

Study question

What is phytoestrogen exposure impact on the reproductive outcomes of women undergoing IVF treatment?

Summary answer

Increased urinary and follicular fluid phytoestrogen concentration were associated with better IVF outcomes.

What is known already

The impact and safety of phytoestrogens, plant-derived isoflavones with estrogenic activity predominantly present in soy, on female reproductive health and on IVF outcomes continues to be hotly debated. Numerous studies suggest healthy benefits of phytoestrogen consumption: protection against reprotoxic substances, reductions in breast and other cancers, fibroids, menopausal symptoms, cardiovascular disease, inflammation, and metabolic syndrome and obesity. However, many studies suggest a harmful effect due to the endocrine-disruptor properties of phytoestrogens in both male and female reproductive tissues. Its impact on IVF treatments success is still understudied.

Study design, size, duration

60 women attending IVI-RMA New Jersey undergoing IVF with single-embryo transfer (SET) of euploid good-quality blastocyst after PGT analysis were recruited. Patients underwent PGT-SET cycles following standard protocols. Concentrations of two phytoestrogens (daidzein and genistein) were measured in follicular fluid (FF) and urine collected at oocyte pick-up (UOP) and urine collected at transfer day (UT). These measurements were correlated with IVF clinical outcomes.

Participants/materials, setting, methods

Participants were aged 18-42 years old 18.5-29.9 kg/m2 BMI. Measure of both phytoestrogens’ concentration in follicular fluid and urine samples collected at two different time-points was performed by UPLC-MSMS, with internal standards. Urine phytoestrogen concentrations were normalized by creatinine, measured by Jaffe reaction. Generalized linear models were employed to explore IVF outcomes association, estimated as percentile 20th to 80th increase (95% confidence intervals), among log-transformed phytoestrogen concentration. Both unadjusted and age-BMI-adjusted models were applied.

Main results and the role of chance

In fully adjusted models, higher sum of phytoestrogen concentration in follicular fluid (FF) were significantly associated with higher estradiol at hCG [1.31 (1.04, 1.65), p = 0.023]; whereas the sum of creatinine-corrected phytoestrogens measured in oocyte pick-up urine (UOP) were significantly associated with higher MII oocytes number [1.29 (1.07, 1.56), p = 0.008] and higher fertilized oocytes number [1.34 (1.10, 1.64), p = 0. 004]. Regarding clinical IVF outcomes, in fully adjusted models a higher follicular fluid and oocyte pick-up urine phytoestrogens concentration was significantly associated with higher implantation ratio [8.60 (1.09, 68.03), p = 0. 023] for FF, and [5.01 (0.96, 26.21), p = 0. 05] for UOP; higher clinical pregnancies ratio [5.58 (1.31, 23.73), p = 0.017] for FF, and [3.25 (0.99, 10.63), p = 0.045] for UOP; higher live newborns ratio [5.58 (1.31, 23.73), p = 0.017] for FF, and [3.25 (0.99, 10.63), p = 0.045] for UOP; and higher number of women with live newborns among those who started treatment [4.29 (1.28, 14.38), p = 0.016] for FF, and [2.83 (0.99, 8.07), p = 0.047] for UOP.

Limitations, reasons for caution

Further studies are needed to confirm this association in other populations, including the measurement of other estrogenic isoflavones and its metabolites.

Wider implications of the findings

This is the first work evaluating the association between phytoestrogens concentrations in different biofluids and IVF reproductive outcomes. Our results, using an euploid SET, suggest a beneficial effect of phytoestrogen consumption in women undergoing IVF treatment, further studies are needed to assess the benefit of phytoestrogen supplementation on IVF outcomes.

Trial registration number

-

P–203 Applying artificial intelligence for ploidy prediction: The concentration of IL–6 in spent culture medium, blastocyst morphological grade and embryo morphokinetics as variables under consideration

Study question

Would it be possible to predict embryo ploidy by taking into account conventional morphological and morphokinetic parameters together with IL–6 concentration in spent culture medium?

Summary answer

Our artificial neural network (ANN) trained with blastocyst morphology, embryo morphokinetics and IL–6 concentration distinguished between euploid/aneuploid embryos in 65% of the testing dataset.

What is known already

The analysis of spent embryo culture media represents the protein and metabolic state of the embryo and could be a non-invasive method of obtaining information about embryo quality. The impact of the presence/absence of several proteins in embryo culture samples over clinical results has been widely studied. The IL–6 is one of the most mentioned protein for its effect on embryo development, implantation and likelihood of achieving a live birth. In this initial attempt, we examined the predictive value for euploidy of a model that took into account the concentration of IL–6 in the spent culture medium.

Study design, size, duration

This prospective study included 319 embryos with PGT-A results. Out of the total, 127 were euploid and 192 aneuploid embryos. Concentration of IL–6 in spent embryo culture media (collected on the day of trophectoderm biopsy-fifth/sixth day of development), morphokinetic parameters (division time to 2 cells-t2; to 3 cells-t3, to 4 cells-t4; to 5 cells-t5 and time of blastocyst formation-tB) and blastocyst morphological grade (according to ASEBIR criteria) were considered to predict the embryo ploidy.

Participants/materials, setting, methods

Embryos were cultured in EmbryoScope. The chromosome analysis was performed using next-generation sequence technology. The concentration of IL–6 was measured in 20µL of spent embryo culture media with ELISA kits. Morphokinetic parameters were automatically annotated and the blastocyst morphology was evaluated by senior embryologists based on blastocele expansion, inner cell mass and trophectoderm quality. All the embryos were divided into 70% for training, 15% for validating and 15% for testing our ANN model with MatLab®.

Main results and the role of chance

The general description for the euploid embryo population was the following: 2% of the embryos were graded as A, 71% were graded as B and 28% were graded as C; the means and standard deviations were 25.32±2.97 hours (h) for t2, 35.33±5.15h for t3, 37.30±5.43h for t4, 48.24±6.62h for t5 and 103.93±12.8h for tB; and the average of IL–6 concentration was 1.51±0.70 pg/ml. The general description for the aneuploid embryo population was the following: 1% of the embryos were graded as A, 48% were graded as B and 51% were graded as C; the means and standard deviations were 26.13±3.51h for t2, 36.70±4.29h for t3, 38.20±4.24h for t4, 49.86±6.89h for t5 and 107.10±8.29h for tB; and the average of IL–6 concentration was 1.47±0.71 pg/ml. Our ANN model showed a higher general success rate as we increased the variables considered in the final prediction of euploid embryos. The accuracy, sensitivity and specificity for the testing dataset were: 0.60, 0.12 and 0.87 with morphokinetic parameters; 0.63, 0.24 and 0.93 with morphokinetics and IL–6 concentration; and 0.65, 0.16 and 0.96 with morphokinetics, IL–6 concentration and blastocyst morphological grade.

Limitations, reasons for caution

The low sensitivity and high specificity achieved in our models indicated that they were more capable of detecting aneuploid than euploid embryos. As this was a preliminary study, the small number of embryos included in the test (n = 48) was also a limitation.

Wider implications of the findings: The results showed that our model tended to classify the embryos as aneuploid. More euploid embryos would be necessary to train our model and achieve better results in the prediction of chromosomally normal embryos. Further studies with large number of embryos and additional variables could improve the non-invasive ploidy prediction.

Trial registration number

Not applicable

P–189 The transcriptional profile of arrested cleavage stage human embryos

Study question

What are the molecular pathways overactivated in arrested cleavage stage human embryos?

Summary answer

There is an upregulation of mitochondrial activity and cellular stress-related pathways in arrested cleavage embryos, which is in agreement with the “quiet hypothesis”.

What is known already

mtDNA content decreases during embryo development, however there is a high increase in mtDNA content in arrested cleavage embryos that may correspond to a response to intrinsic or extrinsic factor creating stress. This reasoning would be in agreement with stablished hypothesis showing that a basal metabolism with a moderate-low energy consumption is actually a sign of embryo health, so a viable embryo does not need to use an extra energy to accommodate to the environment (Leese, 2012). The study of the transcriptional profile during human embryo development will give further information about key molecular process involved in in-vitro embryonic competence.

Study design, size, duration

A prospective cohort study was performed with 11 MII oocytes (average age= 22,9 years), 10 non-arrested cleavage embryos (average age= 29,9 years), 5 arrested cleavage embryos (average age= 38,8 years) and 8 blastocysts (average age= 39,1 years). All specimens were warmed and sampled in PCR tubes with 2 μl of suitable reaction buffer for the RNA sequencing protocol.

Participants/materials, setting, methods

Specimens were analyzed by single-cell RNA sequencing (scRNA-seq). Correlation studies, principal component and differential expression analysis were performed with DESeq2 package. Differential gene expression analyses were done using the parametric Wald test, with Benjamini-Hochberg multiple test correction (padj). Finally, Fgsea algorithm was used for enrichment analysis on Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and Gene ontology (GO) terms.

Main results and the role of chance

We do not observe mitochondria-related activity pathways significantly (P>.05) deregulated between MII oocytes and non-arrested cleavage embryos considering GO and KEGG categories.

When comparing non-arrested cleavage embryos versus blastocysts, we observe several ATP production/consumption and cristae formation-related pathways significantly (P<.05) upregulated in blastocysts compared to non-arrested cleavage embryos considering GO and KEGG categories. This change in activity coincides with the metabolic activation event that occurs in the blastocyst stage.

However, when we analyze arrested cleavage embryos versus non-arrested cleavage embryos, we observe several ATP production related-pathways and mitochondria-related apoptosis pathways significantly (P<.05) upregulated in arrested cleavage embryos compared to non-arrested cleavage embryos considering GO categories. With KEGG categories, we notice a significant (P<.05) upregulation of oxidative phosphorylation in arrested cleavage embryos. On the other hand, when we analyze the differences between arrested cleavage embryos and blastocysts, taking into account the differences related to the change of embryo stage, we do not observe ATP production or consumption-related pathways significantly (P>.05) deregulated considering GO and KEGG categories. Then, human arrested embryos in parallel with the increase in mtDNA content, display an upregulation of mitochondrial activity and cellular stress which is in line with the expected overactive metabolism of non-viable embryos.

Limitations, reasons for caution

All analyzed blastocyst were aneuploid, so we are unable to determine what the results would be with euploid blastocysts. Also, although age can it be ruled out, no differences were observed between mean age from cleavage stage embryos (arrested and non-arrested ones) and blastocyst.

Wider implications of the findings: This study evidences the relation between extreme mtDNA content increase and the identification of the pathways involved in active metabolism and apoptosis in arrested cleavage stage human embryos.

Trial registration number

Not applicable

O-121 Exploring non-invasive methods to predict Ploidy Status: Combination of blastocyst morphology image analysis and proteomic profiles by using Artificial Neural Networks

Study question

Is the blastocyst morphology image analysis combined with the protein content of spent embryo culture medium a suitable way to predict embryo ploidy?

Summary answer

Morphological variables from blastocyst image analysis combined with IL-6 or MMP-1 concentration in spent culture medium showed more than 80% of accuracy for euploidy prediction.

What is known already

An artificial intelligence model based on the proteomic profile of euploid embryos and morphological data from blastocyst time-lapse images has been recently published (Bori et al., 2020). The most promising artificial neural network (ANN) algorithm considered 20 morphological variables extracted from image analysis and two proteins detected in embryo culture medium (MMP-1 and IL-6). The overall success rate on blind test data was 72.7% for live birth prediction. The main aim of the present study was to check if the same morphological variables combined with MMP-1 or IL-6 with a cost-effective technique could discriminate between euploid and aneuploid embryos.

Study design, size, duration

This prospective study included 120 embryos from the preimplantation genetic testing for aneuploidies (PGT-A) program. A single blastocyst image was obtained for each embryo and their spent culture medium was collected on the day 5/6 of embryo development (day of trophectoderm biopsy). Morphological variables were extracted for all the blastocyst. On the other hand, we quantified IL-6 levels of 67 embryos and MMP-1 levels of 53 embryos. Resulting parameters were used to predict PGT-A results.

Participants/materials, setting, methods

Blastocyst images were imported into Matlab software and segmented into regions of interest. We obtained 20 mathematical variables related to measurements of areas, number of pixels and texture analysis. Chromosome analysis was performed using next-generation sequence technology. In parallel, 20 µL of spent culture medium from each blastocyst was analyzed with ELISA kits (IL-6 or MMP-1). Protein concentrations and morphological variables were used as input data for an ANN associated with genetic algorithms.

Main results and the role of chance

The euploid rate for the set of embryos included in the IL-6 group was 51.4%. The ANN was trained with 49 embryos and blind tested with 18 embryos. Following results correspond to euploidy prediction on the blind test. The sensitivity, specificity, accuracy and area under the ROC curve (AUC) were: 0.56, 0.78, 0.67 and 0.72 considering only IL-6 values; 0.88, 0.78, 0.83 and 0.61 considering IL-6 values and blastocyst morphological data extracted from the image analysis. The euploid rate for the set of embryos included in the MMP-1 group was 51.9%. The ANN was trained with 39 embryos and blind tested with 14 embryos. Following results correspond to euploidy prediction on the blind test. The sensitivity, specificity, accuracy and AUC were: 0.71, 0.57, 0.64 and 0.67 considering only MMP-1 values; 0.86, 0.86, 0.86 and 0.61 considering MMP-1 values and morphological data extracted from the image analysis.

Limitations, reasons for caution

The detection limit in protein quantification is the main limitation of our study. The small number of embryos and the specific culture medium used should be considered for the model application.

Wider implications of the findings

Our preliminary results showed that blastocyst morphology and embryo secretomics could be useful for euploidy prediction by using artificial intelligence techniques. These findings may contribute to the emerging era of non-invasive preimplantation genetic testing (ni-PGT-A).

Trial registration number

not applicable

P-203 Applying artificial intelligence for ploidy prediction: The concentration of IL-6 in spent culture medium, blastocyst morphological grade and embryo morphokinetics as variables under consideration

Study question

Would it be possible to predict embryo ploidy by taking into account conventional morphological and morphokinetic parameters together with IL-6 concentration in spent culture medium?

Summary answer

Our artificial neural network (ANN) trained with blastocyst morphology, embryo morphokinetics and IL-6 concentration distinguished between euploid/aneuploid embryos in 65% of the testing dataset.

What is known already

The analysis of spent embryo culture media represents the protein and metabolic state of the embryo and could be a non-invasive method of obtaining information about embryo quality. The impact of the presence/absence of several proteins in embryo culture samples over clinical results has been widely studied. The IL-6 is one of the most mentioned protein for its effect on embryo development, implantation and likelihood of achieving a live birth. In this initial attempt, we examined the predictive value for euploidy of a model that took into account the concentration of IL-6 in the spent culture medium.

Study design, size, duration

This prospective study included 319 embryos with PGT-A results. Out of the total, 127 were euploid and 192 aneuploid embryos. Concentration of IL-6 in spent embryo culture media (collected on the day of trophectoderm biopsy-fifth/sixth day of development), morphokinetic parameters (division time to 2 cells-t2; to 3 cells-t3, to 4 cells-t4; to 5 cells-t5 and time of blastocyst formation-tB) and blastocyst morphological grade (according to ASEBIR criteria) were considered to predict the embryo ploidy.

Participants/materials, setting, methods

Embryos were cultured in EmbryoScope. The chromosome analysis was performed using next-generation sequence technology. The concentration of IL-6 was measured in 20µL of spent embryo culture media with ELISA kits. Morphokinetic parameters were automatically annotated and the blastocyst morphology was evaluated by senior embryologists based on blastocele expansion, inner cell mass and trophectoderm quality. All the embryos were divided into 70% for training, 15% for validating and 15% for testing our ANN model with MatLab®.

Main results and the role of chance

The general description for the euploid embryo population was the following: 2% of the embryos were graded as A, 71% were graded as B and 28% were graded as C; the means and standard deviations were 25.32±2.97 hours (h) for t2, 35.33±5.15h for t3, 37.30±5.43h for t4, 48.24±6.62h for t5 and 103.93±12.8h for tB; and the average of IL-6 concentration was 1.51±0.70 pg/ml. The general description for the aneuploid embryo population was the following: 1% of the embryos were graded as A, 48% were graded as B and 51% were graded as C; the means and standard deviations were 26.13±3.51h for t2, 36.70±4.29h for t3, 38.20±4.24h for t4, 49.86±6.89h for t5 and 107.10±8.29h for tB; and the average of IL-6 concentration was 1.47±0.71 pg/ml. Our ANN model showed a higher general success rate as we increased the variables considered in the final prediction of euploid embryos. The accuracy, sensitivity and specificity for the testing dataset were: 0.60, 0.12 and 0.87 with morphokinetic parameters; 0.63, 0.24 and 0.93 with morphokinetics and IL-6 concentration; and 0.65, 0.16 and 0.96 with morphokinetics, IL-6 concentration and blastocyst morphological grade.

Limitations, reasons for caution

The low sensitivity and high specificity achieved in our models indicated that they were more capable of detecting aneuploid than euploid embryos. As this was a preliminary study, the small number of embryos included in the test (n = 48) was also a limitation.

Wider implications of the findings

The results showed that our model tended to classify the embryos as aneuploid. More euploid embryos would be necessary to train our model and achieve better results in the prediction of chromosomally normal embryos. Further studies with large number of embryos and additional variables could improve the non-invasive ploidy prediction.

Trial registration number

not applicable

Inhibition of KIF20A by BKS0349 reduces endometriotic lesions in a xenograft mouse model

Several studies have suggested a possible etiological association between ovarian endometriosis and ovarian cancer. Evidence has shown that KIF20A overexpression might confer a malignant phenotype to ovarian tumors by promoting proliferation and inhibiting apoptosis. However, no data about the role of KIF20A in endometriosis have been described. In this study, the human endometrium (n = 4) was transfected by mCherry adenovirus and intraperitoneally implanted in mice. Subsequently, mice were divided in three groups (n = 8/group) that were treated with Vehicle, BKS0349 (KIF20A-antagonist) or cabergoline (dopamine receptor agonist) for 21 days. mCherry-labeled endometriotic lesions were monitored over time using the IVIS Imaging System. Mice were sacrificed 72 h after the last administration; proliferation was evaluated by immunohistochemistry and apoptosis by TUNEL. CCND1 gene expression (G1 phase-related gene) was measured by qRT-PCR. A significant reduction in mCherry-fluorescent signal was observed in the BKS0349 group after treatment ended (D24) compared with D0 (P-value = 0.0313). Moreover, the mCherry signal on D24 showed a significant decrease in the BKS0349 group compared with controls (P-value = 0.0303), along with significant size reduction of endometriotic lesions observed in the BKS0349 group compared with control on D24 (P-value = 0.0006). Functional studies showed a significant reduction in proliferating cells in the BKS0349-treated group compared with controls (P-value = 0.0082). In addition, CCND1 expression was decreased in the BKS0349 group compared with control (P-value = 0.049) at D24 and a significant increase in apoptotic cells among endometriotic lesions in BKS0349-treated mice was observed compared with control (P-value = 0.0317). Based on these findings, we concluded that BKS0349 induces apoptosis and inhibits cell proliferation, reducing endometriotic lesion size and suggesting KIF20A inhibition by BKS0349 as a novel therapeutic treatment for endometriosis.

Copper and lead exposures disturb reproductive features of primary endometrial stromal and epithelial cells

This study investigates if Cu and Pb act as endocrine disruptors affecting endometrial cells. Primary EnSCs and EnECs were exposed to Cu (0, 50, 100 and 200 μM) or Pb (0, 30, 100 and 500 μM) and assessed for viability, decidualization, apoptosis and proliferation on EnSCs, and wound healing and adhesion capabilities on EnECs. Cu exposure decreased significantly cell viability in a dose-dependent manner. Cu and Pb negatively affected in vitro decidualization, showing a significant decrease in PRL secretion. HOXA10 and ERα mRNA levels significantly decreased in decidualized cells (dEnSCs) exposed to Cu. Cu and Pb decreased adhesion and regeneration capability in EnEC. This study reveals that Cu and Pb could negatively affect endometrial functionality, compromising the decidualization process and disrupting endometrial regeneration and embryo adhesion. Therefore, special care should be taken considering heavy metals exposure if pregnancy is being pursued.

529. PROPROTEIN CONVERTASE 6 PLAYS A CRITICAL ROLE IN MODULATING THE HUMAN ENDOMETRIAL EPITHELIUM FOR RECEPTIVITY AND IMPLANTATION

Successful embryo implantation is an important step in establishing pregnancy, requiring a healthy embryo and a receptive endometrium. Establishment of endometrial receptivity involves morphological and physiological changes initially in the endometrial epithelium, but the underlying molecular mechanisms are not fully understood. We have previously demonstrated that proprotein convertase 5/6 (PC6), a member of the proprotein convertase (PC) family, is up-regulated in the endometrium specifically at implantation in association with epithelial differentiation, in the human and monkey. PCs convert a range of precursor proteins of important functions into their bioactive forms; they are thus regarded as critical “master switch” molecules. The present study aimed to determine whether PC6 is a critical regulator in the endometrial epithelium for receptivity and implantation. We examined whether endometrial epithelial PC6 dys-regulation is associated with implantation failure in women and whether knockdown of PC6 by siRNA in human endometrial epithelial cells affects embryo adhesion in a cell culture model. Endometrial PC6 expression was assessed by immunohistochemistry in the mid-secretory phase of the menstrual cycle (receptive phase) in two unique clinical cohorts comprising women of known fertility and infertility (with no obvious gynecological disorders, and with fertile males). Endometrial epithelial PC6 levels were significantly lower in infertile vs fertile women in both cohorts. To further establish that PC6 is important for receptivity, a cell model relevant to human implantation was used involving co-culture of uterine epithelial cells with mouse embryos. The epithelial cells were stably transfected with PC6 siRNA and PC6 knock down was confirmed at the levels of mRNA, protein, and activity by real-time RT-PCR, Western blotting and activity assay respectively. Embryos readily adhered to normal epithelial cells, but the adhesion was significantly reduced in the PC6 knockdown epithelial cells. We are currently using proteomics technology to identify the pathways affected by PC6 knockdown. These results strongly suggest that PC6 plays a critical role in modulating the human endometrial epithelium for receptivity and implantation.

CXCL10 and IL-6 induce chemotaxis in human trophoblast cell lines

The investigation of trophoblast chemoattractive molecules in humans is of high interest for the reproductive field. Current evidence in ruminants demonstrates that CXCL10, formerly the interferon-gamma-inducible protein 10 (IP-10), is a potent chemotactic molecule implicated in the migration of trophoblast cells during early gestation. The aim of this work was to explore the existence of CXCL10/CXCR3 in the human model. Furthermore, chemotaxis assays were performed to demonstrate CXCL10 chemotactic activity in the human trophoblast cell lines JEG-3 and AC-1M88. Surprisingly, the conditioned media from epithelial endometrial cells (EEC) induced the highest trophoblast migration rate. Cytokine and chemokine membrane protein arrays were used to identify the secreted protein profile of EEC-conditioned media, and IL-6 was found to be the most abundant and CXCL13 the second most abundant molecule. Using a chemotaxis assay on AC-IM88, IL-6 antibody blocked the effect of EEC, indicating IL-6 to be an effective chemoattractive factor for trophoblast cells in the human model.