Expression of CD82 in human trophoblast and its role in trophoblast invasion

A Potential Role of CD82/KAI1 during Uterine Decidualization in Mice

The tumor metastasis suppressor gene CD82/KAI1 has been demonstrated to impact human trophoblast invasion and migration. Communication between trophoblasts and decidual stromal cells plays a crucial role in controlling the normal invasiveness of trophoblasts. However, whether CD82/KAI1 is involved in decidualization and what role it plays remain unclear. CD82/KAI1 demonstrates specific spatiotemporal expression patterns in stromal cells undergoing decidualization during pregnancy. This is observed in both naturally pregnant females post-implantation and pseudopregnant mice undergoing induced decidualization, as detected through in situ hybridization and immunofluorescence. CD82/KAI1 expression showed a significant time-dependent increase in cultured stromal cells after 24 and 48 h of progesterone (P4) and estrogen (E2) treatment. This was accompanied by a notable upregulation of decidualization markers, including cyclin D3 and PR. After transducing stromal cells with the adenovirus-overexpressing CD82/KAI1 for 48 h, the expression of cyclin D3 protein increased. Meanwhile, there was an attenuated expression of CD82/KAI1 due to an adenovirus siRNA knockdown, whereas cyclin D3 and PR expressions were not affected. Our findings suggest a potential role of CD82/KAI1 in regulating the process of decidualization, providing insights into stromal cell differentiation.

Research progress of E3 ubiquitin ligase regulating biological behavior of human placental trophoblast cells

E3 ubiquitin ligases are important components of the ubiquitin protease system. This family includes many proteins, which can catalyze the ubiquitination of a variety of protein substrates and promote the degradation of them by the proteasome system. Recent studies have shown that E3 ubiquitin ligase plays a key role in the process of fetal development and placental formation. It affects the biological behavior of placental trophoblast cells, leading to a series of pregnancy complications that threaten mothers and babies greatly. This review focuses on the regulation, target and mechanism of E3 ubiquitin ligase on the biological behavior of human placental trophoblast cells.

Advanced Maternal Age-associated SIRT1 Deficiency Compromises Trophoblast Epithelial-Mesenchymal Transition through an Increase in Vimentin Acetylation

Advanced maternal age (AMA) pregnancies are rapidly increasing and are associated with aberrant trophoblast cell function, poor placentation, and unfavorable pregnancy outcomes, presumably due to premature placental senescence. SIRT1 is an NAD⁺ -dependent deacetylase with well-known antiaging effects, but its connection with placental senescence is unreported. In this study, human term placentas and first-trimester villi were collected from AMA and normal pregnancies, and a mouse AMA model was established by cross breeding young and aged male and female C57 mice. SIRT1 expression and activity in HTR8/SVneo cells were genetically or pharmacologically manipulated. Trophoblast-specific Sirt1-knockout (KO) mouse placentas were generated by mating Elf5-Cre and Sirt1^fl/fl mice. Trophoblast cell mobility was assessed with transwell invasion and wound-healing assays. SIRT1-binding proteins in HTR8/SVneo cells and human placental tissue were identified by mass spectrometry. We identified SIRT1 as the only differentially expressed sirtuin between AMA and normal placentas. It is downregulated in AMA placentas early in the placental life cycle and is barely impacted by paternal age. SIRT1 loss upregulates P53 acetylation and P21 expression and impairs trophoblast invasion and migration. Sirt1-KO mouse placentas exhibit senescence markers and morphological disruption, along with decreased fetal weight. In trophoblasts, SIRT1 interacts with vimentin, regulating its acetylation. In conclusion, SIRT1 promotes trophoblast epithelial-mesenchymal transition (EMT) to enhance invasiveness by modulating vimentin acetylation. AMA placentas are associated with premature senescence during placentation due to SIRT1 loss. Therefore, SIRT1 may be an antiaging therapeutic target for improving placental development and perinatal outcomes in AMA pregnancies.

Roles of tetraspanins during trophoblast development: bioinformatics and new perspectives

Tetraspanins are a superfamily of membrane proteins found in all eukaryotic organisms. They act as scaffold molecules that regulate the traffic and function of other membrane/signaling proteins, resulting in important downstream cellular consequences. The aim of this work was to use transcriptomes and bioinformatics analysis to identify the tetraspanins (and their partners) involved in trophoblast differentiation. We built a protein-protein interaction network around tetraspanins which revealed that tetraspanins CD9, CD81, and CD82 show a specific expression during trophoblast differentiation. These proteins appeared to be interconnected and to recruit several membrane partners which include integrins, immune-related molecules, and a variety of receptors. During weeks 8 to 24, a CD9 expression trajectory was identified in extravillous trophoblasts, and a website was developed: ( https://extravillous.shinyapps.io/CD9humanEVT/ ). In conclusion, CD81 may, together with CD9 and CD82, be interconnected in controlling trophoblast invasion in the endometrium. CD9 expression trajectory in extravillous trophoblast between weeks 8 and 24 shows the involvement of CD9 in cell adhesion and migration.

Aquaporin 3 promotes human extravillous trophoblast migration and invasion

PROBLEM

Does aquaporin 3 (AQP3) affect the migration and invasion of human extravillous trophoblast (HTR8/Svneo) cells?

METHOD OF STUDY

A lentivirus infection system was used to construct stable cell lines with either AQP3 knockdown or overexpression. RT-PCR and western blotting were used to verify the efficiencies of AQP3 knockdown or overexpression in HTR8/Svneo cells at mRNA and protein levels, respectively. Cell Counting Kit-8 and flow cytometry assays were used to detect the influence of AQP3 knockdown or overexpression on proliferation and apoptosis of HTR8/Svneo cells. In addition, wound healing and Transwell invasion assays were used to detect the effects of AQP3 knockdown or overexpression on migration and invasion capabilities of HTR8/Svneo cells. An Agilent gene chip was used to screen for significant differentially expressed genes after AQP3 knockdown. Finally, mechanisms by which AQP3 influences the migration and invasion of HTR8/Svneo cells were explored using bioinformatic analysis.

RESULTS

Compared with controls, migration and invasion capabilities of HTR8/Svneo cells were significantly reduced after AQP3 knockdown, and significantly increased after AQP3 overexpression. Subsequent bioinformatic analysis of gene chip expression profiles indicated downregulation of genes related to adhesion such as PDGF-B, as well as signaling pathways (such as PIK3/AKT, NF-κB, and TNF) after AQP3 knockdown.

CONCLUSIONS

AQP3 could significantly promote migration and invasion capabilities of human extravillous trophoblasts, it may mediate embryo invasion and adhesion to endometrium by regulating PDGF-B, PIK3/AKT signaling pathways, although this requires further verification.

Trophoblast-derived CXCL12 promotes CD56bright CD82- CD29+ NK cell enrichment in the decidua

PROBLEM

Decidual natural killer (dNK) cells play key roles in maternal-fetal immune regulation, trophoblast invasion, and vascular remodeling, and most dNK cell populations are CD56^bright CD16^- NK cells. However, the enrichment and redistribution of dNK cells in the local decidua have not been clarified yet.

METHOD OF STUDY

A total of 45 women with normal pregnancies and 8 unexplained recurrent spontaneous abortion (RSA) patients were included. We isolated primary human dNK (n = 53) and peripheral blood NK (pNK) cells (n = 5) from specimen and analyzed CD56, CD82, and CD29 by flow cytometry (FCM). We assessed their adhesion ability by cell counts of NK cells adhered to decidual stromal cells (DSCs) in a co-culture system.

RESULTS

We found that RSA patients had more CD56^dim dNK cells with lower CD82 and higher CD29 than women with normal pregnancies. There were negative correlations of CD82 to CD29 on CD56^dim and CD56⁺ dNK cells. In normal pregnancies, dNK cells had lower CD82 and higher CD29 expression with a stronger adhesion ability than pNK cells. Blocking CD82 on dNK cells increased the adhesive ability and CD29 expression, while blocking CD29 decreased the adhesive ability. Co-culturing dNK cells with trophoblast cells decreased CD82 expression and increased the adhesive ability of dNK cells and the percentage of CD56^bright NK cells, while blocking trophoblast-derived CXCL12 increased CD82 expression, decreased CD29 expression, and impaired the adhesive ability of NK cells.

CONCLUSION

Trophoblast cells enhance the adhesive ability of NK cells to DSCs via the CXCL12/CD82/CD29 signaling pathway and contribute to CD56^bright NK cell enrichment in the uterus.

Dysregulated Expression of RPS4Y1 (Ribosomal Protein S4, Y-Linked 1) Impairs STAT3 (Signal Transducer and Activator of Transcription 3) Signaling to Suppress Trophoblast Cell Migration and Invasion in Preeclampsia

Normal placentation and a successful pregnancy depend on appropriate trophoblast cell migration and invasion. Inadequate trophoblast invasion and impaired spiral artery remodeling may lead to pregnancy-related disorders, such as preeclampsia. RPS4Y1 (ribosomal protein S4, Y-linked 1) is a member of the S4E family of ribosomal proteins. In this study, we found that RPS4Y1 levels were upregulated in placental samples collected from preeclamptic patients, when compared with the normotensive pregnant women. In vitro, inhibition of RPS4Y1 induced trophoblast cell invasion, promoted placental explant outgrowth, and increased STAT3 (signal transducer and activator of transcription 3) phosphorylation along with elevated expression of N-cadherin and vimentin. Conversely, overexpression of RPS4Y1 results in reduced trophoblast cell invasion and decreased STAT3 phosphorylation. In addition, the suppression of RPS4Y1 promotes trophoblast cell invasion, which could be abolished by the STAT3 knockdown. Meanwhile, we observed reductions of STAT3 phosphorylation expression in preeclampsia patients. Collectively, these results demonstrate that the level of RPS4Y1 expression may be associated with preeclampsia by affecting trophoblast cell migration and invasion via the STAT3/epithelial-mesenchymal transition pathway.

N-cadherin knockdown leads to disruption of trophoblastic and endothelial cell interaction in a 3D cell culture model - New insights in trophoblast invasion failure

INTRODUCTION

Trophoblast homing to maternal spiral arteries is mandatory for successful placentation. Cell-cell adhesion molecules regulate this process and adhesion molecule expression is altered in impaired placentation. We hypothesize that, similar to immune cell recruitment, trophoblast cell adherence and rolling are primarily mediated by adhesion molecules like, cadherins, immunoglobulins, selectins and their partnering ligands. Here, the interdependence of adhesion molecule expression in trophoblastic cell lines of diverse origin was investigated in relation to their interaction with endothelial cell networks on Matrigel® co-cultures and the effect of specific adhesion molecule knockdown analyzed.

METHODS

Trophoblastic cells were labeled in red and co-cultured with green HUVEC networks on Matrigel®. Association was quantified after collection of fluorescence microscopy pictures using Wimasis® internet platform and software. Expression of adhesion molecules was analyzed by PCR and Western blot, immuno-fluorescence and flow cytometry. The impact of adhesion molecules on trophoblast-endothelial-cell interaction was investigated using siRNA technique.

RESULTS

N-cadherin and CD162 were specifically expressed in the trophoblast cell line HTR-8/SVneo, which closely adhere to and actively migrate toward HUVEC networks on Matrigel®. Suppression of N-cadherin led to a significant alteration in trophoblast-endothelial cell interaction. Expression of VE-cadherin in closely interacting trophoblast cells was not confirmed in vitro.

DISCUSSION

We identified N-cadherin to mediate specific interaction between HUVEC and the migrating trophoblast cells HTR-8/SVneo in a Matrigel® co-culture model. VE-cadherin contribution could not be confirmed in vitro. Our results support the hypothesis that impaired N-cadherin but not VE-cadherin expression is involved in trophoblast recruitment to the maternal endothelium.

Positive Regulation of Decidualization by l-Type Amino Acid Transporter 1 (lat1) in Pregnant Mice

Amino acids have an important role in the pre and post implantation of placenta and embryo development. l-type amino-acid transporter 1 (lat1) is responsible for the transportation of large neutral amino acids and is mainly expressed in human fetal liver, placenta, brain, etc. This study is the first to investigate the expression of lat1 in the early pregnancy of mouse uteri and its role in the process of decidualization. Endometrial stromal cells of a mouse model were used to evaluate decidualization from Day 4–8 of pregnancy in vitro followed by lat1 knock down by small interfering RNA and by a competitive inhibitor of Leucine transport 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH). The effects of lat1 on decidualization in vivo were assessed by injecting BCH into the uterine horns. The mRNA and protein expressions of lat1 in the implantation sites were higher than that in the inter-implantation sites and were localized in the luminal and gland epithelium, stromal and decidual cells. Its increased expression (p < 0.05) was associated with artificial decidualization as well as activation of prl expression. Down-regulation of lat1 expression in these cells by siRNA and BCH inhibited the decidual progression in vitro. Inhibition of lat1 transportation by BCH controlled decidual progression in vivo also accompanied the down-regulation of prl, lat1 expression in the decidual area and embryo size on Day 8 of pregnancy. In conclusion, these results revealed that lat1 might play an important role in the decidual progression both in vitro and in vivo.

DNA methylation-associated repression of MEST/PEG1 expression contributes to the invasion of extravillous trophoblast cells

INTRODUCTION

The invasion of extravillous cytotrophoblasts (EVTs) into the maternal uterine decidua and vasculature is critical for human placenta development and pregnancy maintenance. The imprinted gene MEST/PEG1 has been implicated in trophoblast development; however, the role of MEST in EVT invasion and the accompanying early pregnancy complications are not fully understood.

METHODS

Western blot, immunofluorescence and immunohistochemistry were used to detect MEST protein expression and localization by using antibodies recognize 2 reported isoforms. Specific small interference RNA (siRNA) targeting both of the MEST isoforms was applied to silence MEST expression in extravillous explants and HTR8/SVneo cells. Cell invasion and migration were assessed using the Matrigel invasion, Transwell migration assay and the xCELLigence system. Promoter DNA methylation was examined using bisulfite-sequencing polymerase chain reaction (BSP).

RESULTS

MEST protein was highly expressed in EVTs in the first trimester placenta and in the invasive EVT cell lines HTR-8/Svneo and HPT-8. Weak MEST expression was found in cytotrophoblasts (CTBs) and the choriocarcinoma-derived CTB cell line JEG-3. The specific siRNA knockdown of MEST expression significantly reduced HTR-8/Svneo cell invasion and migration as well as extravillous explant outgrowth, which were associated with the downregulation of Twist, N-cadherin and Vimentin. Decreased MEST protein expression with isoform 2 promoter hypermethylation was observed in the placentas of missed abortions, suggesting a possible pathological mechanism of missed abortion.

CONCLUSIONS

Suppressed expression of MEST was associated with its isoform 2 promoter hypermethylation ex vivo placenta tissues and in vitro cultured EVT cell lines. The present results provide a possible pathological mechanism of missed abortion.

Oxidative stress-induced Gadd45α inhibits trophoblast invasion and increases sFlt1/sEng secretions via p38 MAPK involving in the pathology of pre-eclampsia

BACKGROUND

Pre-eclampsia (PE) is one of the most common pregnancy-related complications. We have previously reported that growth arrest and DNA damage-inducible 45 alpha (Gadd45α) is over-expressed in trophoblasts in pre-eclamptic placentas, with an excessive activation of p38 mitogen-activated protein kinase (MAPK) and increased levels of soluble Fms-like tyrosine kinase 1 (sFlt-1) and soluble endoglin (sEng) in maternal sera. Now we further investigate how Gadd45α regulates trophoblast functions and anti-angiogenesis factors secretions during placental development in patients with PE.

METHODS

Human placental villous explants were used to verify the effects of Gadd45α and p38 MAPK in placentation. Then HRT8/SVneo cells exposed to hypoxia/reoxygenation (H/R) were employed as an oxidative stress model to investigate the effects of Gadd45α on invasion and sFlt-1/sEng secretions. Through silencing Gadd45α with lentiviral vector-based short-hairpin RNA and inhibiting p38 MAPK with SB203580, we demonstrated that Gadd45α and its downstream p38 protein played roles in the pathology of pre-eclampsia.

RESULTS

Gadd45α was found to have increased expression in H/R-treated villous explants and HTR8/SVneo cells. Gadd45α knockdown or p38 blockage could promote trophoblast outgrowth and migration in H/R-exposed villous explants, and enhance the potentials of trophoblast migration/invasion and network formation in H/R-exposed HTR8/SVneo cells. These functional changes might be related to the increased activities of MMP2/9. Meanwhile, Gadd45α knockdown or p38 inhibition also decreases sFlt-1/sEng secretions via suppressing oxidative stress.

CONCLUSIONS

Oxidative stress-induced overexpression of Gadd45α might influence the activity of MMPs through activation of p38 MAPK signaling to affect the invasion of trophoblast cells, and increase the secretions of sFlt-1/sEng, which then participate in the pathogenesis of pre-eclampsia.

Oxidative stress-induced C/EBPβ inhibits β-catenin signaling molecule involving in the pathology of preeclampsia

INTRODUCTION

Oxidative stress-induced trophoblast cell dysfunction is a major pathology in preeclampsia (PE). Recently, CCAAT/enhancer binding protein beta (C/EBPβ) has been investigated as a tumor suppressor that participates in tumor invasion. However, the function of C/EBPβ in trophoblast cells remains unknown. Our study was designed to detect the expression of C/EBPβ in the preeclamptic placenta and to identify the underlying mechanisms of oxidative stress.

METHODS

Human placental tissues with PE were collected. The expression of C/EBPβ and β-catenin were detected. Human first trimester extravillous trophoblast cell (HTR8/SVneo) line exposed to hypoxia/reoxygenation (H/R) was employed as an oxidative stress model in vitro to investigate the effects of C/EBPβ on invasion and the expression of β-catenin. Moreover, first trimester-derived placental villous explants were used to verify the effects of C/EBPβ and β-catenin in placentation.

RESULTS

In preeclamptic placentas, C/EBPβ was overexpressed and β-catenin was decreased. In addition, C/EBPβ was found to have increased expression in H/R-treated HTR8/SVneo cells and villous explants. C/EBPβ knockdown and β-catenin activation could significantly promote the invasion of HTR8/SVneo cells, enhance the outgrowth and migration in villous explants and inhibit the excessive generation of intracellular ROS. These findings might be related to the increased activities of MMP-2/9 and the decreased expression of TIMP-1/2. Meanwhile, C/EBPβ knockdown remarkably increased the expression of β-catenin.

DISCUSSION

We hypothesize that the oxidative stress-induced overexpression of C/EBPβ might influence the activity of MMPs by regulating the Wnt/β-catenin signaling pathway to affect the invasion of trophoblast cells, which then participate in the pathogenesis of preeclampsia.

Downregulation of CD9 in keratinocyte contributes to cell migration via upregulation of matrix metalloproteinase-9

Tetraspanin CD9 has been implicated in various cellular and physiological processes, including cell migration. In our previous study, we found that wound repair is delayed in CD9-null mice, suggesting that CD9 is critical for cutaneous wound healing. However, many cell types, including immune cells, endothelial cells, keratinocytes and fibroblasts undergo marked changes in gene expression and phenotype, leading to cell proliferation, migration and differentiation during wound repair, whether CD9 regulates kerationcytes migration directly remains unclear. In this study, we showed that the expression of CD9 was downregulated in migrating keratinocytes during wound repair in vivo and in vitro. Recombinant adenovirus vector for CD9 silencing or overexpressing was constructed and used to infect HaCaT cells. Using cell scratch wound assay and cell migration assay, we have also demonstrated that downregulation of CD9 promoted keratinocyte migration in vitro, whereas CD9 overexpression inhibited cell migration. Moreover, CD9 inversely regulated the activity and expression of MMP-9 in keratinocytes, which was involved in CD9-regulated keratinocyte migration. Importantly, CD9 silencing-activated JNK signaling was accompanied by the upregulation of MMP-9 activity and expression. Coincidentally, we found that SP600125, a JNK pathway inhibitor, decreased the activity and expression of MMP-9 of CD9-silenced HaCaT cells. Thus, our results suggest that CD9 is downregulated in migrating keratinocytes in vivo and in vitro, and a low level of CD9 promotes keratinocyte migration in vitro, in which the regulation of MMP-9 through the JNK pathway plays an important role.