Abstract Placental stress has been implicated in the pathophysiology of complications of pregnancy, including growth restriction and pre-eclampsia. Initially, attention focused on oxidative stress, but recently mitochondrial and endoplasmic reticulum stress have been identified. Complex molecular interactions exist among these different forms of stress, making it unlikely that any occurs in isolation. In part, this is due to close physiological connections between the two organelles principally involved, mitochondria and the endoplasmic reticulum (ER), mediated through Ca2+ signalling. Here, we review the involvement of the mitochondria-ER unit in the generation of stress within the trophoblast, and consider consequences for obstetric outcome. Mild stress may induce adaptive responses, including upregulation of antioxidant defences and autophagy, while moderate levels may affect stem cell behaviour and reduce cell proliferation, contributing to the growth-restricted phenotype. High levels of stress can stimulate release of pro-inflammatory cytokines and anti-angiogenic factors, increasing the risk of pre-eclampsia. In addition, chronic stress may promote senescence of the trophoblast, which in other cell types leads to a pro-inflammatory senescence-associated secretory phenotype. Evidence from rodents suggests that a degree of trophoblastic stress develops with increasing gestational age in normal pregnancies. The increase in maternal concentrations of soluble fms-like tyrosine kinase-1 (sFlt-1) and reduction in placental growth factor (PlGF) suggest the same may occur in the human, starting around 30 weeks of pregnancy. Placental malperfusion, or co-existing maternal conditions, such as diabetes, will exacerbate that stress. Amelioration of trophoblastic stress should remain a research priority, but will be difficult due to the complexity of the molecular pathways involved.
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 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. Trophoblast cells are specialized cells in the placenta that mediate the interactions between the fetus and mother. Okae et al. report the derivation of human trophoblast stem cells from blastocysts and early placentas, which will provide a powerful tool to study human placental development and function.
Extravillous trophoblasts (EVTs) migrate into uterine decidua and induce vascular smooth muscle cell (VSMC) loss through mechanisms thought to involve migration and apoptosis, achieving complete spiral artery remodeling. Long noncoding RNA maternally expressed gene 3 (MEG3) can regulate diverse cellular processes, such as proliferation and migration, and has been discovered highly expressed in human placenta tissues. However, little is known about the role of MEG3 in modulating EVT functions and EVT‐induced VSMC loss. In this study, we first examined the location of MEG3 in human first‐trimester placenta by in situ hybridization. Then, exogenous upregulation of MEG3 in HTR‐8/SVneo cells was performed to investigate the effects of MEG3 on EVT motility and EVT capacity to displace VSMCs. Meanwhile, the molecules mediating EVT‐induced VSMC loss, such as tumor necrosis factor‐α (TNF‐α), Fas ligand (FasL), and tumor necrosis factor‐α‐related apoptosis‐inducing ligand (TRAIL) were detected at transcriptional and translational levels. Finally, VSMCs were cocultured with MEG3‐upregulated HTR‐8/SVneo to explore the role of MEG3 on EVT‐mediated VSMC migration and apoptosis. Results showed that MEG3 was expressed in trophoblasts in placental villi and decidua, and MEG3 enhancement inhibited HTR‐8/SVneo migration and invasion. Meanwhile, the displacement of VSMCs by HTR‐8/SVneo and the expression of TNF‐α, FasL and TRAIL in HTR‐8/SVneo were reduced following MEG3 overexpression in HTR‐8/SVneo. Furthermore, HTR‐8/SVneo with MEG3 upregulation impaired VSMC migration and apoptosis. The PI3K/Akt pathway, which is possibly downstream, was inactivated in MEG3‐upregulated HTR‐8/SVneo. These findings suggest that MEG3 might be a negative regulator of spiral artery remodeling via suppressing EVT invasion and EVT‐mediated VSMC loss. Maternally expressed gene 3 (MEG3) suppressed trophoblast‐mediated vascular smooth muscle cell (VSMC) migration and apoptosis, which might be associated with reduced expression of tumor necrosis factor‐α (TNF‐α), Fas ligand (FasL), and tumor necrosis factor‐α‐related apoptosis‐inducing ligand (TRAIL) in trophoblast with MEG3 enhancement.
Background: The trophoblast compartment of the placenta comprises various subpopulations with distinct functions. They interact among each other by secreted signals thus forming autocrine or paracrine regulatory loops. We established a first trimester trophoblast cell line (ACH-3P) by fusion of primary human first trimester trophoblasts (week 12 of gestation) with a human choriocarcinoma cell line (AC1-1). Results: Expression of trophoblast markers (cytokeratin-7, integrins, matrix metalloproteinases), invasion abilities and transcriptome of ACH-3P closely resembled primary trophoblasts. Morphology, cytogenetics and doubling time was similar to the parental AC1-1 cells. The different subpopulations of trophoblasts e. g., villous and extravillous trophoblasts also exist in ACH-3P cells and can be immuno-separated by HLA-G surface expression. HLA-G positive ACH-3P display pseudopodia and a stronger expression of extravillous trophoblast markers. Higher expression of insulin-like growth factor II receptor and human chorionic gonadotropin represents the basis for the known autocrine stimulation of extravillous trophoblasts. Conclusion: We conclude that ACH-3P represent a tool to investigate interaction of syngeneic trophoblast subpopulations. These cells are particularly suited for studies into autocrine and paracrine regulation of various aspects of trophoblast function. As an example a novel effect of TNF-alpha on matrix metalloproteinase 15 in HLA-G positive ACH-3P and explants was found.
Critical roles for DNA methylation in embryonic development are well established, but less is known about its roles during trophoblast development, the extraembryonic lineage that gives rise to the placenta. We dissected the role of DNA methylation in trophoblast development by performing mRNA and DNA methylation profiling of mutants. We find that oocyte-derived methylation plays a major role in regulating trophoblast development but that imprinting of the key placental regulator is only partially responsible for these effects. We have identified several methylation-regulated genes associated with trophoblast differentiation that are involved in cell adhesion and migration, potentially affecting trophoblast invasion. Specifically, trophoblast-specific DNA methylation is linked to the silencing of , a Polycomb Repressive Complex 1 protein that drives loss of cell adhesion in methylation-deficient trophoblast. Our results reveal that maternal DNA methylation controls multiple differentiation-related and physiological processes in trophoblast via both imprinting-dependent and -independent mechanisms. Branco et al. dissect the role of DNA methylation in mouse trophoblast development through genome-wide profiling of methylation-deficient mutants. DNA methylation marks carried over from the oocyte play a major role in trophoblast development and cell adhesion, which is partly dependent on silencing of the Polycomb gene .
Objective To examine the expression pattern of biomarker proteins in extravillous trophoblast (EVT) cells obtained noninvasively by trophoblast retrieval and isolation from the cervix (TRIC) in patients with early pregnancy loss compared with control patients with uncomplicated term delivery. Design Case-control study. Setting Academic medical center. Patient(s) Women with either early pregnancy loss (EPL, n = 10) or an uncomplicated term delivery (N = 10). Intervention(s) Endocervical specimens obtained from ongoing pregnancies at gestational ages of 5–10 weeks to generate an archive of EVT cells isolated by TRIC, with medical records examined to select specimens matched for gestational age at the time of endocervical sampling. Main Outcome Measure(s) Known serum biomarkers for adverse pregnancy outcome that are expressed by EVT cells were evaluated by semiquantitative immunocytochemistry, using antibodies against endoglin (ENG), FMS-like tyrosine kinase-1 (FLT-1), α-fetoprotein (AFP), pregnancy-associated plasma protein-A (PAPP-A), galectin-13 (LGALS13), galectin-14 (LGALS14), and placental growth factor (PGF). Result(s) The EVT purity was over 95% in all specimens, based on chorionic gonadotropin expression; however, the number of EVT cells obtained was significantly lower in women with EPL than the control group. There was a statistically significant elevation of AFP, ENG, and FLT-1, and statistically significant reduction of PAPP-A, LGALS14, and PGF in the EPL group compared with controls. Conclusion(s) In this pilot study, EVT cells isolated by TRIC early in gestation exhibited altered protein expression patterns before an EPL compared with uncomplicated term pregnancies.
Abstract Despite the high incidence of trophoblast-related diseases, the molecular mechanism of inadequate early trophoblast development is still unclear due to the lack of an appropriate cellular model in vitro. In the present study, we reprogrammed the amniotic cells to be induced pluripotent stem cells (iPSCs) via a non-virus and non-integrated method and subsequently differentiated them into trophoblast-like cells by a modified BMP4 strategy in E6 medium. Compared with the previously studied trophoblast-like cells from ESCs, the iPSCs derived trophoblast-like cells behave similarly in terms of gene expression profiles and biofunctions. Also we confirmed the differentiating tendency from iPSCs to be syncytiotrophoblasts-like cells might be caused by inappropriate differentiating oxygen condition. Additionally, we preliminarily indicated in vitro “artificial” differentiation of iPSCs also undergoing a possible trophoblastic stem cell stage, as witnessed in vivo. In conclusion, we provided an in vitro cellular model to study early trophoblast development for specific individual, by using the feasible amnion.