RNA profiling of laser microdissected human trophoblast subtypes at mid-gestation
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ABSTRACT: Human placental architecture is complex. Its surface epithelium, specialized for transport, forms by fusion of cytotrophoblast progenitors into multinucleated syncytiotrophoblasts. Near the uterine surface, these progenitors assume a different fate, becoming cancer-like cells that invade its lining and blood vessels. The latter process physically connects the placenta to the mother and shunts uterine blood to the syncytiotrophoblasts. Isolation of trophoblast subtypes is technically challenging. Upon removal, syncytiotrophoblasts disintegrate and invasive cytotrophoblasts are admixed with uterine cells. We used laser capture to circumvent these obstacles. This enabled isolation of syncytiotrophoblasts and two subpopulations of invasive cytotrophoblasts—cell column and endovascular. Transcriptional profiling revealed numerous genes whose placental or trophoblast expression was not known, including neurotensin and C4ORF36. Using mass spectrometry, discovery of differentially expressed mRNAs was extended to the protein level. We also found that invasive cytotrophoblasts expressed cannabinoid receptor 1. Unexpectedly, screening agonists and antagonists showed signals from this receptor promote invasion. Together these results revealed novel gene expression patterns that translate to the protein level. Our data also suggested that endogenous and exogenous cannabinoids can affect human placental development.
Project description:Human placental architecture is complex. Its surface epithelium, specialized for transport, forms by fusion of cytotrophoblast progenitors into multinucleated syncytiotrophoblasts. Near the uterine surface, these progenitors assume a different fate, becoming cancer like cells that invade its lining and blood vessels. The latter process physically connects the placenta to the mother and shunts uterine blood to the syncytiotrophoblasts. Isolation of trophoblast subtypes is technically challenging. Upon removal, syncytiotrophoblasts disintegrate and invasive cytotrophoblasts are admixed with uterine cells. We used laser capture to circumvent these obstacles. This enabled isolation of syncytiotrophoblasts and two subpopulations of invasive cytotrophoblasts; cell column and endovascular. Transcriptional profiling revealed numerous genes whose placental or trophoblast expression was not known, including neurotensin and C4ORF36. Using mass spectrometry, discovery of differentially expressed mRNAs was extended to the protein level. We also found that invasive cytotrophoblasts expressed cannabinoid receptor 1. Unexpectedly, screening agonists and antagonists showed signals from this receptor promote invasion. Together these results revealed novel gene expression patterns that translate to the protein level. Our data also suggested that endogenous and exogenous cannabinoids can affect human placental development.
Project description:The mechanisms by which the placenta adapts to exogenous stimuli to create a stable and healthy environment for the growing fetus are not well known. Low oxygen tension and sub-optimal vitamin D levels influence placental function and both are associated with preeclampsia, a condition associated with altered development of placental trophoblast. We hypothesized that oxygen tension, vitamin D levels, or both affect villous trophoblast by modulation of gene expression through DNA methylation. To test this we used the Illumina Infinium Human Methylation 450 BeadChip array to compare the DNA methylation profile of primary cultures of human cytotrophoblasts and syncytiotrophoblasts under three oxygen tensions and three vitamin D levels. We found no effect on global DNA methylation by either treatment, but a limited set of loci became hypermethylated in cytotrophoblasts exposed for 24 hours to 1% oxygen, as compared to the same cells exposed to 8% or 20% oxygen. Vitamin D levels had no detectable effect on methylation profiles in either trophoblast type. Hypermethylation with low oxygen tension was independently confirmed by bisulfite-pyrosequencing in a subset of functionally important genes including CP, ITGA5, SOD2, XDH and ZNF2. Intriguingly, 70 out of the 147 hypoxia-associated CpGs, overlapped with CpG sites that become hypomethylated upon differentiation of cytotrophoblasts into syncytiotrophoblasts. Furthermore, the preponderance of altered sites was located at AP-1 binding sites. We suggest that AP-1 expression is triggered by hypoxia and interacts with DNA methyltransferases (DNMTs) to target methylation at specific sites in the genome, thus causing suppression of the associated genes that are responsible for differentiation of villous cytotrophoblast to syncytiotrophoblast. RNA from cytotrophoblast from 2 placentas exposed to 3 different conditions of hypoxia (1%,8%,20%) and treated with 3 levels of vitamin D were run on the Illumina HT-12v4 Expression Array
Project description:The mechanisms by which the placenta adapts to exogenous stimuli to create a stable and healthy environment for the growing fetus are not well known. Low oxygen tension and sub-optimal vitamin D levels influence placental function and both are associated with preeclampsia, a condition associated with altered development of placental trophoblast. We hypothesized that oxygen tension, vitamin D levels, or both affect villous trophoblast by modulation of gene expression through DNA methylation. To test this we used the Illumina Infinium Human Methylation 450 BeadChip array to compare the DNA methylation profile of primary cultures of human cytotrophoblasts and syncytiotrophoblasts under three oxygen tensions and three vitamin D levels. We found no effect on global DNA methylation by either treatment, but a limited set of loci became hypermethylated in cytotrophoblasts exposed for 24 hours to 1% oxygen, as compared to the same cells exposed to 8% or 20% oxygen. Vitamin D levels had no detectable effect on methylation profiles in either trophoblast type. Hypermethylation with low oxygen tension was independently confirmed by bisulfite-pyrosequencing in a subset of functionally important genes including CP, ITGA5, SOD2, XDH and ZNF2. Intriguingly, 70 out of the 147 hypoxia-associated CpGs, overlapped with CpG sites that become hypomethylated upon differentiation of cytotrophoblasts into syncytiotrophoblasts. Furthermore, the preponderance of altered sites was located at AP-1 binding sites. We suggest that AP-1 expression is triggered by hypoxia and interacts with DNA methyltransferases (DNMTs) to target methylation at specific sites in the genome, thus causing suppression of the associated genes that are responsible for differentiation of villous cytotrophoblast to syncytiotrophoblast. DNA from 2 cell types from 5 placentas exposed to 3 different conditions of hypoxia (1%,8%,20%) and treated with 3 levels of vitamin D were bisulfite converted and run on the Illumina HumanMethylation450 BeadChip
Project description:As susceptibility to many adult disorders originates in utero, we here hypothesized that fetal sex influences gene expression in placental cells and produces functional differences in human placentas. We found that fetal sex differentially affects gene expression in a cell-phenotype dependent manner among all four placental cell-phenotypes studied: cytotrophoblasts, syncytiotrophoblasts, arterial endothelial cells and venous endothelial cells. The markedly enriched pathways in males were identified to be signaling pathways for graft-versus-host disease as well as the immune and inflammatory systems, both supporting the hypothesis that there is reduced maternal-fetal compatibility for male fetuses. Our study is the first microarray study investigating sexual dimorphism in purified and characterized somatic cells from a single human tissue, the placenta, that underlines the importance of considering fetal sex as an independent variable in any work using human placenta. Arterial and venous endothelial cells were isolated from eight different placentas, four of each sex. A total of ten placentas were used for isolation of cytotrophoblasts and six for syncytiotrophoblasts, with equal numbers from each sex.
Project description:Placental trophoblasts are key determinants of in utero development. Mouse trophoblast stem cells (mTSCs), which were first derived over a decade ago, are a powerful cell culture model for studying their self-renewal or differentiation. Our attempts to isolate an equivalent population from the trophectoderm of human blastocysts generated colonies that quickly differentiated in vitro. This finding suggested that the human placenta has another progenitor niche. Here we show that the chorion is one such site. Initially, we immunolocalized pluripotency factors and trophoblast fate determinants in the early-gestation placenta, amnion and chorion. Immunoreactive cells were numerous in the chorion. We isolated these cells and plated them in medium containing FGF and an inhibitor of activin/nodal signaling, which is required for human embryonic SC self-renewal. Colonies of polarized cells with a limited lifespan emerged. Trypsin dissociation yielded continuously self-replicating monolayers. Colonies and monolayers formed the two major human trophoblast lineages—multinucleate syncytiotrophoblasts and invasive cytotrophoblasts (CTBs). Transcriptional profiling experiments revealed the factors associated with the self-renewal or differentiation of human chorionic trophoblast progenitor cells (TBPCs). They included imprinted genes, NR2F1/2, HMGA2 and adhesion molecules that were required for TBPC differentiation. Together, the results of these experiments suggested that the chorion is one source of epithelial CTB progenitors. These findings explain why CTBs of fully formed chorionic villi have a modest mitotic index and identify the chorionic mesoderm as a niche for TBPCs that support placental growth. TBPC colonies (3 biological replicates), TPBC monolayers (2 biological replicates), CTB (3 biological replicates), hESC (3 biological replicates)
Project description:Invasion of cytotrophoblasts into uterine tissues is essential for placental development. To identify molecules regulating trophoblast invasion, mRNA signatures of purified villous (CTB, poor invasiveness) and extravillous (EVT, high invasiveness) trophoblasts isolated from first trimester human placentae and villous explant cultures, respectively, were compared using GeneChip analyses yielding 991 invasion/migration related transcripts. Several genes involved in physiological and pathologic cell invasion, including ADAM-12,-19,-28 as well as Spondin-2, were upregulated in EVT. Pathway prediction analyses identified several functional modules associated with either the invasive or the non-invasive trophoblast phenotype. One of the genes which were downregulated in the invasive mRNA pool, heme oxygenase-1 (HO-1), was selected for functional analyses. Real-time PCR analyses, Western blottting, and immunofluorescene of first trimester placentae and differentiating villous explant cultures demonstrated downregulation of HO-1 in invasive EVT as compared to CTB. Modulation of HO-1 expression in loss-of as well as gain-of function cell models (BeWo and HTR8/SVneo, respectively) demonstrated an inverse relationship of HO-1 expression with trophoblast migration in transwell and wound healing assays. Importantly, HO-1 expression led to an increase in protein levels and activity of the nuclear hormone receptor PPARgamma. Pharmacological inhibition of PPARgamma abrogated the inhibitory effects of HO-1 on trophoblast migration. Collectively, our results demonstrate that gene expression profiling of EVT and CTB can be used to unravel novel regulators of cell invasion. Accordingly, we identify heme oxygenase-1 as a negative regulator of trophoblast motility acting via upregulation of PPARgamma. Experiment Overall Design: To identify genes potentially regulating cell invasion trophoblast cells of early human gestation with distinct invasive properties were profiled. Experiment Overall Design: Distinct gene expression signatures of highly invasive EVT (n = 6) and poorly invasive CTB (n = 5) of different first trimester placentae using Affymetrix U133A GeneChips interrogating >20,000 genes were determined.
Project description:The mechanisms by which the placenta adapts to exogenous stimuli to create a stable and healthy environment for the growing fetus are not well known. Low oxygen tension and sub-optimal vitamin D levels influence placental function and both are associated with preeclampsia, a condition associated with altered development of placental trophoblast. We hypothesized that oxygen tension, vitamin D levels, or both affect villous trophoblast by modulation of gene expression through DNA methylation. To test this we used the Illumina Infinium Human Methylation 450 BeadChip array to compare the DNA methylation profile of primary cultures of human cytotrophoblasts and syncytiotrophoblasts under three oxygen tensions and three vitamin D levels. We found no effect on global DNA methylation by either treatment, but a limited set of loci became hypermethylated in cytotrophoblasts exposed for 24 hours to 1% oxygen, as compared to the same cells exposed to 8% or 20% oxygen. Vitamin D levels had no detectable effect on methylation profiles in either trophoblast type. Hypermethylation with low oxygen tension was independently confirmed by bisulfite-pyrosequencing in a subset of functionally important genes including CP, ITGA5, SOD2, XDH and ZNF2. Intriguingly, 70 out of the 147 hypoxia-associated CpGs, overlapped with CpG sites that become hypomethylated upon differentiation of cytotrophoblasts into syncytiotrophoblasts. Furthermore, the preponderance of altered sites was located at AP-1 binding sites. We suggest that AP-1 expression is triggered by hypoxia and interacts with DNA methyltransferases (DNMTs) to target methylation at specific sites in the genome, thus causing suppression of the associated genes that are responsible for differentiation of villous cytotrophoblast to syncytiotrophoblast.
Project description:The mechanisms by which the placenta adapts to exogenous stimuli to create a stable and healthy environment for the growing fetus are not well known. Low oxygen tension and sub-optimal vitamin D levels influence placental function and both are associated with preeclampsia, a condition associated with altered development of placental trophoblast. We hypothesized that oxygen tension, vitamin D levels, or both affect villous trophoblast by modulation of gene expression through DNA methylation. To test this we used the Illumina Infinium Human Methylation 450 BeadChip array to compare the DNA methylation profile of primary cultures of human cytotrophoblasts and syncytiotrophoblasts under three oxygen tensions and three vitamin D levels. We found no effect on global DNA methylation by either treatment, but a limited set of loci became hypermethylated in cytotrophoblasts exposed for 24 hours to 1% oxygen, as compared to the same cells exposed to 8% or 20% oxygen. Vitamin D levels had no detectable effect on methylation profiles in either trophoblast type. Hypermethylation with low oxygen tension was independently confirmed by bisulfite-pyrosequencing in a subset of functionally important genes including CP, ITGA5, SOD2, XDH and ZNF2. Intriguingly, 70 out of the 147 hypoxia-associated CpGs, overlapped with CpG sites that become hypomethylated upon differentiation of cytotrophoblasts into syncytiotrophoblasts. Furthermore, the preponderance of altered sites was located at AP-1 binding sites. We suggest that AP-1 expression is triggered by hypoxia and interacts with DNA methyltransferases (DNMTs) to target methylation at specific sites in the genome, thus causing suppression of the associated genes that are responsible for differentiation of villous cytotrophoblast to syncytiotrophoblast.
Project description:Zika virus (ZIKV) infection at the maternal-placental interface is associated with adverse pregnancy outcomes including fetal demise and pregnancy loss. To determine how infection impacts placental trophoblasts, we utilized rhesus macaque trophoblast stem cells (TSC) that can be differentiated into early gestation syncytiotrophoblasts (ST) and extravillous trophoblasts (EVT). TSCs and STs, but not EVTs, were highly permissive to productive infection with ZIKV strain DAK AR 41524. The impact of ZIKV on the cellular transcriptome showed that infection of TSCs and STs increased expression of immune related genes, including those involved in type I and type III interferon responses. ZIKV exposure altered extracellular vesicle (EV) protein, mRNA, and miRNA cargo, regardless of productive infection. These findings suggest that early gestation macaque TSCs and STs are permissive to ZIKV infection, and that EV analysis may provide a foundation for identifying non-invasive biomarkers of placental infection in a highly translational model.
Project description:The hemochorial placentation site is characterized by a dynamic interplay between trophoblast cells and maternal cells. These cells cooperate to establish an interface required for nutrient delivery to promote fetal growth. In the human, trophoblast cells penetrate deep into the uterus. This is not a consistent feature of hemochorial placentation and has hindered the establishment of suitable animal models. The rat represents an intriguing model for investigating hemochorial placentation with deep trophoblast cell invasion. In this study, we used single cell RNA sequencing to characterize the transcriptome of the invasive trophoblast cell lineage, as well as other cell populations within the rat uterine-placental interface during early (gestation day, gd, 15.5) and late (gd 19.5) stages of intrauterine trophoblast cell invasion. We identified a robust set of transcripts that define invasive trophoblast cells, as well as transcripts that distinguished endothelial, smooth muscle, natural killer, and macrophage cells. Invasive trophoblast, immune, and endothelial cell populations exhibited distinct spatial relationships within the uterine-placental interface. Furthermore, the maturation stage of invasive trophoblast cell development could be determined by assessing gestation-stage dependent changes in transcript expression. Finally, and most importantly, expression of a prominent subset of rat invasive trophoblast cell transcripts is conserved in the invasive extravillous trophoblast cell lineage of the human placenta. These findings provide foundational data to identify and interrogate key conserved regulatory mechanisms essential for development and function of an important compartment within the hemochorial placentation site that is essential for a healthy pregnancy.