scholarly journals Trophectoderm differentiation to invasive syncytiotrophoblast is induced by endometrial epithelial cells during human embryo implantation

2020 ◽  
Author(s):  
Peter T Ruane ◽  
Terence Garner ◽  
Lydia Parsons ◽  
Phoebe A Babbington ◽  
Susan J Kimber ◽  
...  

AbstractAt implantation, trophoblast derived from the trophectoderm of the blastocyst-stage embryo invades the endometrium to establish pregnancy. To understand how embryos breach the endometrial epithelium, we modelled human implantation using blastocysts or trophoblast stem cell spheroids cultured with endometrial epithelial cells (EEC). Blastocyst invasion of the EEC layer was initiated by multinuclear syncytiotrophoblast. Spheroids also invaded the epithelium with syncytiotrophoblast, and EEC induced upregulation of syncytiotrophoblast markers. Modelling implantation in silico using blastocyst and EEC transcriptomes revealed gene networks that exhibited greater connectivity and organisation in trophectoderm of the polar region of the embryonic axis. However, gene ontologies and machine learning suggested that EEC drives syncytiotrophoblast differentiation in polar and mural trophectoderm. This is the first evidence for endometrial epithelium-induced trophectoderm differentiation to invasive syncytiotrophoblast as the cellular mechanism of embryonic breaching of the endometrium in humans, with implications for reproductive medicine and our understanding of human embryonic development.

2010 ◽  
Vol 22 (9) ◽  
pp. 74
Author(s):  
S. Heng ◽  
Y. Li ◽  
A. N. Stephens ◽  
A. Rainczuk ◽  
G. Nie

Successful embryo implantation is an important step in establishing pregnancy, which requires a healthy embryo and a receptive endometrium. Establishment of endometrial receptivity involves morphological and physiological changes initially in the endometrial epithelium, however 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 aim of this study was to identify target proteins of PC6 in the endometrial epithelial cells important for implantation. We used a HEC1A cell line in which PC6 was stably knocked down by siRNA approach (HEC1A-PC6). HEC1A cells that were similarly transfected with a scrambled siRNA sequence (HEC1A-control) were used as the control. Previous study confirmed that HEC1A-PC6 cells had much reduced capacity to adhere to blastocyst. A proteomic comparison between HEC1A-PC6 treated with or without human recombinant PC6 identified ezrin as a potential PC6 substrate. Ezrin is a cytoplasmic protein which is known to bind to ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) thereby translocating to the plasma membrane.This complex has been associated with cytoskeletal re-organisation and changes in cell polarity. Co-immunoprecipitation of ezrin and EBP50 showed that knockdown of PC6 allowed the binding of ezrin to the C-terminus of EBP50 in HEC1A-PC6, whereas PC6 cleavage of EBP50 in HEC1A-control prevented the binding. This was also confirmed by immunofluorescence showing that ezrin and EBP50 were co-localized to the plasma membrane in HEC1A-PC6. This study thus identified that PC6 regulates scaffolding proteins such as EBP50 and ezrin in the endometrium for embryo implantation.


2021 ◽  
Author(s):  
Abhishek Tiwari ◽  
Nancy Ashray ◽  
Neha Singh ◽  
Shipra Sharma ◽  
Deepak N Modi

The endometrium is a dynamic tissue that undergoes extensive remodelling to attain a receptive state which is further modulated in presence of an embryo for successful initiation of pregnancy. Cadherins are the proteins of junctional complex of which E-cadherin (E-Cad) is crucial for maintaining epithelial cell state and integrity of the epithelial barrier; gain of N-cadherin (N-Cad) in epithelial cells leads to epithelial to mesenchymal transition (EMT). In the present study, we aimed to investigate the expression of E-Cad and N-Cad in the mouse endometrial luminal epithelium and its modulation by estrogen, progesterone and embryonic stimuli. We observed that E-Cad is diffusely expressed in the luminal epithelium of mouse endometrium during the estrus stage and upon estrogen treatment. It is apico-laterally and basolaterally sorted at the diestrus stage and in response to combined treatment of estrogen and progesterone. In 3D spheroids of human endometrial epithelial cells, combined treatment with estrogen and progesterone led to lateral sorting of E-Cad. In the mouse endometrium at the time of embryo implantation, there is loss of E-Cad which was associated with the gain of N-Cad suggestive of EMT in the luminal epithelium. This EMT is possibly driven by embryonic stimuli as treatment with estrogen and progesterone did not lead to gain of N-Cad expression. In conclusion, the present study demonstrates that steroid hormones directly affect E-Cad sorting in the endometrial epithelium.


2009 ◽  
Vol 21 (9) ◽  
pp. 124
Author(s):  
P. Paiva ◽  
K. Meehan ◽  
L. A. Salamonsen ◽  
E. Dimitriadis

Emerging evidence suggests an important role for the early embryo product human chorionic gonadotrophin (hCG) in embryo-endometrial interactions critical for successful embryo implantation1. The human endometrium is also a source of hCG, with maximal expression of hCG and its receptor, hCG/LHR, in endometrial epithelial cells during the window of implantation in vivo2,3, and in primary endometrial epithelial cells (EECs)3. Implantation is tightly regulated by growth and regulatory factors produced within the embryo-endometrial microenvironment. We hypothesise that embryo/endometrial-derived hCG mediates the molecular cross talk vital for successful implantation. The main objective of this study was to investigate the effect of hCG on the production of a selected cohort of 42 cytokines and growth factors by EECs. These included those with both known and previously unidentified roles during implantation. The secretory profile of cytokines/growth factors produced by EECs was also analysed. EECs (n=8 cultures) were isolated from biopsies collected from fertile cycling women. Cells were treated without or with recombinant hCG for 48 hr and conditioned media collected for quantitative analysis using LuminexTM multiplex technology. For the first time, a secretory profile of 42 cytokines and growth factors produced by EECs was established, as was the identification of fibroblast growth factor-2 (FGF-2) secretion by human endometrial epithelium. hCG (2 IU/ml) significantly increased the production of a number factors including those with known roles during trophoblast migration and adhesion (CX3CL1; 71±31%, CXCL10; 67±24%, CCL4; 87±12%), in trophoblast differentiation (IL-1α ; 68±31%) and with unidentified roles during implantation (CCL22; 78±40%, GM-CSF; 45±16%, FGF-2; 50±25%; all p<0.05). Upregulation of the known hCG regulated proteins, VEGF and LIF, validated this study. These findings clearly support roles for the embryo/endometrium via hCG in actively contributing to the molecular cross-talk during the early stages of implantation.


Author(s):  
Chia-Hung Chou ◽  
Shee-Uan Chen ◽  
Chin-Der Chen ◽  
Chia-Tung Shun ◽  
Wen-Fen Wen ◽  
...  

Abstract Context A supraphysiological estradiol (E2) concentration after ovarian stimulation is known to result in lower embryo implantation rates in in vitro fertilization (IVF). Endometrial epithelial cells (EECs) apoptosis occurs after the stimulation with high E2 concentrations, and mitochondria play important roles in cell apoptosis. Objective To investigate the mitochondrial function in EECs after the stimulation with high E2 concentrations. Materials and Methods Human EECs were purified and cultured with different E2 concentrations (10-10, 10-9, 10-8, 10-7 M) in vitro, in which 10-7 M is supraphysiologically high. Eight-week-old female mouse endometrium was obtained 5.5 days after the injection of 1.25 IU or 20 IU equine chorionic gonadotropin (eCG), roughly during the embryo implantation window, to examine the in vivo effects of high E2 concentrations on mouse EECs. Results In vivo and in vitro experiments demonstrated decreased mitochondrial DNA contents and ATP formation after EECs were stimulated with supraphysiologically high E2 concentrations than those stimulated with a physiologic E2 concentration. Less prominent immunofluorescence mitochondrial staining, fewer mitochondria number under electron microscopy, lower JC-1 aggregate/monomer ratio, and greater reactive oxygen species (ROS) production were found after EECs were stimulated with supraphysiologically high E2 concentrations. The high E2-induced ROS production was reduced when EECs were pretreated with N-acetyl-cysteine (NAC) in vitro, but remained unchanged after the pretreatment with coenzyme Q10. Conclusion High E2 concentrations increase extra-mitochondrial ROS production in EECs and subsequently result in mitochondrial dysfunction.


2020 ◽  
Vol 26 (11) ◽  
pp. 825-836
Author(s):  
Bing Wang ◽  
Yan Shao

Abstract We previously showed that annexin A2 (Axna2) was transiently expressed at the embryo-uterine luminal epithelium interface during the window of implantation and was involved in mouse embryo implantation. At the same time, Axna2 was reported to be upregulated in human receptive endometrium, which was critical for embryo attachment as an intracellular molecule. Here, we identified Axna2 as a membrane-bound molecule on human endometrial epithelial cells and trophoblast cells, and the outer surface membrane-bound Axna2 was involved in human embryo attachment. In addition, physiological levels of estrogen and progesterone increased the expression of overall Axna2 as well as that in the extracellular surface membrane protein fraction in human endometrial cells. Furthermore, p11 (or S100A10, a member of the S100 EF-hand family protein, molecular weight 11 kDa) was involved in the translocation of Axna2 to the outer surface membrane of endometrial epithelial cells without affecting its overall expression. Finally, the surface relocation of Axna2 was also dependent on cell–cell contact and calcium binding. A better understanding of the function and regulation of Axna2 in human endometrium may help us to identify a potential therapeutic target for subfertile and infertile patients.


2009 ◽  
Vol 21 (9) ◽  
pp. 128
Author(s):  
G. Nie ◽  
Y. Li ◽  
L. A. Salamonsen ◽  
C. Simon ◽  
A. Quiñonero ◽  
...  

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.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sophie Kinnear ◽  
Lois A. Salamonsen ◽  
Mathias Francois ◽  
Vincent Harley ◽  
Jemma Evans

Abstract The yin and yang of female fertility is a complicated issue; large numbers of women/couples desire fertility and seek assisted reproduction intervention to achieve conception, while others seek to prevent pregnancy. Understanding specific molecules which control endometrial-embryo interactions is essential for both facilitating and preventing pregnancy. SOX17 has recently emerged as an important transcription factor involved in endometrial receptivity and embryo implantation. However, studies to date have examined mouse models of pregnancy which do not necessarily translate to the human. Demonstration of a role for ‘implantation factors’ in a human system is critical to provide a rationale for in depth clinical investigation and targeting of such factors. We demonstrate that SOX17is present within the receptive human endometrium and is up-regulated within human endometrial epithelial cells by combined estrogen & progesterone, the hormonal milieu during the receptive window. SOX17 localizes to the point of adhesive contact between human endometrial epithelial cells and a human ‘embryo mimic’ model (trophectodermal spheroid). Targeting SOX17 in endometrial epithelial cells using CRISPR/Cas9 knockdown or a SOX-F family inhibitor, MCC177, significantly inhibited adhesion of an trophectodermal spheroids to the epithelial cells thereby preventing ‘implantation’. These data confirm the important role of endometrial SOX17 in human endometrial receptivity and embryo implantation.


1997 ◽  
Vol 82 (8) ◽  
pp. 2607-2616 ◽  
Author(s):  
Carlos Simón ◽  
MarÍa José Gimeno ◽  
Amparo Mercader ◽  
José Enrique O’Connor ◽  
José RemohÍ ◽  
...  

In the present study, we examined the embryonic regulation ofβ 3 integrin in human endometrial epithelial cells (EEC) at the protein level and analyzed putative embryonic factors responsible for this regulation. The model employed is based on a clinical in vitro fertilization program in which single human embryos were cocultured with EEC until blastocyst stage and then transferred back to the uterus. After embryo transfer, EEC wells were divided according to the embryonic status reached: EEC with embryos that achieved the blastocyst stage, EEC with arrested embryos, and EEC without embryos. Immunostaining for β3 was positive in plasma membrane of EEC. Flow cytometry showed a mean percentage ofβ 3-stained cells of 24.1 ± 5.7 in EEC cocultured with embryos that achieved the blastocyst stage (n = 13) vs. 9.5 ± 1.6 (P &lt; 0.05) in those EEC cultured with arrested embryos (n = 12). Immunostaining for α1 and α4 integrins was negative in EEC monolayers studied, regardless of the presence or absence of embryos, and these findings were confirmed by flow cytometry. The possibility that the embryonic IL-1 system and leukemia inhibitory factor were involved in the endometrial β3 up-regulation was investigated by neutralizing experiments demonstrating a significant inhibition of β3-stained cells when EEC monolayers were cultured in the presence of EEC/blastocyst-conditioned media with (n = 4) vs. without (n = 8) antihuman interleukin (IL)-1α + IL-1β (1.65% vs. 14.6%; P &lt; 0.05). Dose-response experiments further demonstrated an up-regulation of β3 positive cells when IL-1α + IL-1β were added to the medium at a concentration of 10 pg/mL compared with control medium without added cytokines (40% vs. 20%, n = 4). The functional relevance of the EEC β3 up-regulation was tested using a mouse blastocyst adhesion assay. More mouse blastocysts attached to EEC previously in contact with human blastocyst (72.7%) compared with those EEC previously in contact with arrested embryos (40%). Our results demonstrate the selective effect of a developing human embryo on EEC expression of β3, which is maximal when a human blastocyst instead of an arrested embryo is considered. Furthermore, the embryonic IL-1 system seems to be involved in the EECβ 3 up-regulation, reinforcing the concept of precise paracrine cross-talk between blastocyst and endometrial epithelium during embryonic implantation.


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