Intermediate trophoblast—A distinctive, unique and often unrecognized population of trophoblastic cells

The Placenta and Neonatal Encephalopathy with a Focus on Hypoxic-Ischemic Encephalopathy

Background: Placental examination is important for its diagnostic immediacy to correlate with maternal and/or fetal complications and parturitional difficulties. In a broader context, clinicopathologic studies of the placenta have addressed a range of pathogenetic questions that have led to conclusive and inconclusive results and interpretations. Methods: Recent standardized morphologic criteria and terminology of placental lesions have facilitated the ability to compare findings from studies that have focused on complications and outcomes of pregnancy. This review is an evaluation of recent studies on placental lesions associated with hypoxic-ischemic encephalopathy (HIE). Conclusion: No apparent consensus exists on whether it is fetal inflammation with the release of cytokines or chronic maternal and/or fetal vascular malperfusion is responsible for HIE with a lowering of the threshold for hypoxic ischemia. The counter argument is that HIE occurs solely as an intrapartum event. Additional investigation is necessary.

Colnoy-stimulating factor 1 positive (CSF1+ ) secretory epithelial cells induce excessive trophoblast invasion in tubal pregnancy rupture

Tubal ectopic pregnancy (TEP) occurs when an embryo aberrantly implants in the fallopian tube, leading to abortive or ruptured tubal ectopic pregnancy (AEP or REP). Poor outcomes of REP include maternal infertility or mortality. Current studies on the prevention and treatment of ruptured tubal ectopic pregnancy (REP) are unfortunately hampered by a lack of the cell spectrum and cell-cell communications in the maternal-foetal interface. Here, we investigate the mechanisms of tubal rupture through single-cell transcriptome profiling of the fallopian tube-trophoblast interface in REP, AEP and intrauterine pregnancy patients. In REP, extravillous trophoblast (EVTs) cells form a dominant cell population, displaying aggressive invasion and proliferation, with robust differentiation into three subsets. Cell communication analysis identified colony-stimulating factor 1 (CSF1), overexpressed by fallopian tube secretory epithelial cells in REP, with CSF1R on EVTs and macrophages, as a ligand/receptor pair that stimulates EVT invasion and macrophage accumulation. CSF1+ secretory epithelial cells stimulate EVTs migration and invasion, leading to a tubal rupture in REP. These results provide a mechanistic context and cellular milieu leading to tubal rupture, facilitating further study and development of therapeutics for REP in early pregnancy.

Epithelioid Trophoblastic Tumour: A Case with Genetic Linkage to a Child Born over Seventeen Years Prior, Successfully Treated with Surgery and Pembrolizumab

Epithelioid trophoblastic tumours are rare neoplasms showing differentiation towards the chorion leave-type intermediate cytotrophoblast, with only a handful of cases being reported in the literature. These tumours are slow-growing and are typically confined to the uterus for extended periods of time. While the pathogenesis is unclear, they are thought to arise from a remnant intermediate trophoblast originating from prior normal pregnancies or, less frequently, gestational trophoblastic tumours. A protracted time period between the gestational event and tumour development is typical. This case describes a 49-year-old previously healthy female who presented with a completely asymptomatic uterine mass, discovered incidentally during a routine gynaecological assessment. The pathological analysis of the hysterectomy specimen confirmed an epithelioid trophoblastic tumour, involving the uterus and cervix. This is a rare gynaecological tumour. A comparative short tandem repeat analysis revealed genetic similarities to a previous healthy gestation seventeen years prior. She was successful treated with adjuvant pembrolizumab, with no evidence of disease recurrence to date.

The Role of the Adhesion Receptor CD146 and Its Soluble Form in Human Embryo Implantation and Pregnancy

CD146 is an adhesion molecule essentially located in the vascular system, which has been described to play an important role in angiogenesis. A soluble form of CD146, called sCD146, is detected in the bloodstream and is known as an angiogenic factor. During placental development, CD146 is selectively expressed in extravillous trophoblasts. A growing body of evidence shows that CD146 and, in particular, sCD146, regulate extravillous trophoblasts migration and invasion both in vitro and in vivo. Hereby, we review expression and functions of CD146/sCD146 in the obstetrical field, mainly in pregnancy and in embryo implantation. We emphasized the relevance of quantifying sCD146 in the plasma of pregnant women or in embryo supernatant in the case of in vitro fertilization (IVF) to predict pathological pregnancy such as preeclampsia or implantation defect. This review will also shed light on some major results that led us to define CD146/sCD146 as a biomarker of placental development and paves the way toward identification of new therapeutic targets during implantation and pregnancy.

Abnormal Cullin1 neddylation-mediated p21 accumulation participates in the pathogenesis of recurrent spontaneous abortion by regulating trophoblast cell proliferation and differentiation

The study explores the role of neddylation in early trophoblast development and its alteration during the pathogenesis of recurrent spontaneous abortion (RSA). Immunofluorescence and western blot were conducted to evaluate the expression pattern of NEDD8 protein in the first-trimester placentas of healthy control and RSA patients. Neddylated-cullins, especially neddylated-cullin1, were downregulated and their substrate, p21, was accumulated in RSA samples. NEDD8 cytoplasmic recruitment was observed in extravillous trophoblast (EVT) progenitors of RSA placentas. Consistent with the results of clinical samples, neddylation inhibition using MLN4924 in trophoblast cell lines caused obvious p21 accumulation and free NEDD8 cytoplasmic recruitment. Further in vitro study demonstrated neddylation inhibition attenuated proliferation of Jeg-3 cells via p21 accumulation. Moreover, when trophoblast stem (TS) cells derived from first-trimester placentas were cultured for differentiation analyses. MLN4924 impaired the differentiation of TS cells towards EVTs by downregulating HLA-G and GATA3. p21 knockdown could partly rescue MLN4924-suppressed HLA-G and GATA3 expression. In conclusion, cullin1 neddylation-mediated p21 degradation is required for trophoblast proliferation and can affect trophoblast plasticity by affecting HLA-G and GATA3 expression. The results provide insights into the pathological mechanism of RSA and the biological regulation of trophoblast development.

Histone Deacetylase Sirtuin 2 Enhances Viability of Trophoblasts Through p65-Mediated MicroRNA-146a/ACKR2 Axis

Reduced activity of trophoblast cells is well-recognized to lead to preeclampsia (PE) progression. This study aims to evaluate the roles of histone deacetylase sirtuin 2 (SIRT2) in activity of trophoblast cells and the molecules involved. Differentially expressed genes in placental tissues between PE patients and healthy individuals were screened using microarray analyses. SIRT2 and atypical chemokine receptor 2 (ACKR2) were downregulated while miR-146a was upregulated in PE patients. SIRT2 was localized in placental syncytiotrophoblasts. Upregulation of SIRT2 enhanced viability, migration and invasion, while reduced apoptosis of HTR-8/SVneo cells. SIRT2 was found to trigger p65 deacetylation level and suppress miR-146a expression according to the luciferase and ChIP assays, whereas miR-146a was found to target ACKR2. Downregulation of p65 promoted migration and invasion of cells. Overexpression of miR-146a inhibited cell viability and blocked the function of SIRT2. ACKR2 was downregulated in tissues from PE women and its upregulation blocked the role of miR-146a. To conclude, SIRT2 promotes p65 deacetylation to suppress miR-146a expression and upregulates ACKR2 expression, therefore enhancing proliferation, migration, and invasion of HTR-8/SVneo cells. This study may offer novel thoughts into the management of PE.

Dysfunction of Shh signaling activates autophagy to inhibit trophoblast motility in recurrent miscarriage

In early pregnancy, the placenta anchors the conceptus and supports embryonic development and survival. This study aimed to investigate the underlying functions of Shh signaling in recurrent miscarriage (RM), a serious disorder of pregnancy. In the present study, Shh and Gli2 were mainly observed in cytotrophoblasts (CTBs), Ptch was mainly observed in syncytiotrophoblasts (STBs), and Smo and Gli3 were expressed in both CTBs and STBs. Shh signaling was significantly impaired in human placenta tissue from recurrent miscarriage patients compared to that of gestational age-matched normal controls. VEGF-A and CD31 protein levels were also significantly decreased in recurrent miscarriage patients. Furthermore, inhibition of Shh signaling impaired the motility of JAR cells by regulating the expression of Gli2 and Gli3. Intriguingly, inhibition of Shh signaling also triggered autophagy and autolysosome accumulation. Additionally, knockdown of BECN1 reversed Gant61-induced motility inhibition. In conclusion, our results showed that dysfunction of Shh signaling activated autophagy to inhibit trophoblast motility, which suggests the Shh pathway and autophagy as potential targets for RM therapy.

Establishment and characterization of a new human first trimester Trophoblast cell line, AL07

INTRODUCTION

The limited cell number of primary trophoblasts and contamination of trophoblast cell lines promote us to develop a novel stable trophoblast cell line.

METHOD OF STUDY

Primary trophoblast cells were isolated from first-trimester placenta and telomerase-induced immortalization was used to immortalize these cells. Subsets of cells were then evaluated by flow cytometry using CK7, HLA-G, CD45 and CD14, specific markers for trophoblast cells, extra-villous trophoblast, pan leucocyte and monocyte/macrophage, respectively. Immunofluorescence staining and immunocytochemistry were used to detect CK7 expression in trophoblast cells. The level of secreted human Chorionic Gonadotropin (hCG) was measured by electrochemiluminescence (ECL). The Bio-Plex MAGPIX System was used to analyze the cytokines and chemokines produced by AL07 cell line.

RESULTS

We were able to isolate primary trophoblast cells from several first-trimester placentas. One clone, AL07 trophoblast cells, isolated from a week 7 placenta, was morphologically stable and positive for the expression of CK7 by immunofluorescence and immunocytochemistry staining. Characterization of AL07 cells reveled that they are CD45 or CD14 negative and had constitutive secretion of hCG and low HLA-G expression. Furthermore, clone AL07 secret high levels of several cytokines and chemokines, including IL-6, IL-8 and VEGF, and moderately secreted MCP-1 IP-10 and RANTES.

DISCUSSION

We report the successful isolation, immortalization and characterization of AL07 cells, a novel cell clone isolated from first trimester human placenta. The clone is free of contamination of immune cells, and exhibits similar cytokine profile as other trophoblast cell lines. This new cytotrophoblast-like AL07 cell, can be a valuable tool for in-vitro trophoblast studies in the future.

Involvement of ILR4α and TLR4 in miscarriages

BACKGROUND

The purpose of this study was to analyze the involvement of signaling via Interleukin-4-Receptor α (IL4Rα) and Toll like receptor (TLR) 4 at the fetomaternal interface in the process of early pregnancy.

PATIENTS AND METHODS

Placenta specimens of 46 patients in early pregnancy were analyzed (normal pregnancy (n = 15), spontaneous (n = 15) and habitual abortion (n = 16)). TLR4 and IL4Rα were analyzed by immunohistochemistry, immunofluorescence and real time PCR. Statistical analysis was carried out using SPSS 23 and Microsoft Excel.

RESULTS

IL4Rα could be detected in trophoblast cells of all groups. It was significantly downregulated in the syncytiotrophoblast of spontaneous and recurrent abortions (p = 0.001), and in decidual tissue of spontaneous abortions (p = 0.001). Expression of TLR4 was decreased in the intermediate villous trophoblast (IVT) and decidua of spontaneous abortions (p = 0.04 & 0.003, respectively). On mRNA level expression of IL4Rα and TLR4 was significantly decreased in the group of recurrent miscarriages (IL4Rα p = 0.002, TLR4 p = 0.004).

CONCLUSION

This study contributes new findings to the understanding of the complex molecular interplay at the fetomaternal interface in normal pregnancy and miscarriages. For the first time signaling via IL4Rα being involved at the very beginning of the generation of new life could demonstrated. Moreover, new evidence was provided regarding TLR4 playing a pivotal role in early pregnancy.

Derivation of Human Trophoblast Stem Cells

Trophoblast cells play an essential role in the interactions between the fetus and mother. Mouse trophoblast stem (TS) cells have been derived and used as the best in vitro model for molecular and functional analysis of mouse trophoblast lineages, but attempts to derive human TS cells have so far been unsuccessful. Here we show that activation of Wingless/Integrated (Wnt) and EGF and inhibition of TGF-β, histone deacetylase (HDAC), and Rho-associated protein kinase (ROCK) enable long-term culture of human villous cytotrophoblast (CT) cells. The resulting cell lines have the capacity to give rise to the three major trophoblast lineages, which show transcriptomes similar to those of the corresponding primary trophoblast cells. Importantly, equivalent cell lines can be derived from human blastocysts. Our data strongly suggest that the CT- and blastocyst-derived cell lines are human TS cells, which will provide a powerful tool to study human trophoblast development and function.