Single-nucleus multi-omic profiling of human placental syncytiotrophoblasts identifies cellular trajectories during pregnancy [placenta-ncbi-cell-line_ChIPseq_cuttag]
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ABSTRACT: The human placenta plays vital roles in ensuring a successful pregnancy. Despite the growing body of knowledge about its cellular compositions and functions, however, there has been limited research on the heterogeneity of the billions of nuclei within the syncytiotrophoblast (STB), a multinucleated entity primarily responsible for placental function. Here, we conducted integrated snRNA-seq and snATAC-seq on human placentas from early and late pregnancy. Our findings demonstrate the dynamic heterogeneity and developmental trajectories of STB nuclei and their presence in human trophoblast stem cells (hTSCs)-derived STB. Furthermore, we identified transcription factor (TF) motifs that are biased towards diverse STB nuclear lineages through their associated gene regulatory networks. The role of these TFs in STB differentiation were confirmed in the hTSCs- and trophoblast organoid-derived STB. Together, our data provide valuable insights into the heterogeneity of human STB and represents a valuable resource for interpreting its associated pregnancy complications.
Project description:The human placenta plays vital roles in ensuring a successful pregnancy. Despite the growing body of knowledge about its cellular compositions and functions, however, there has been limited research on the heterogeneity of the billions of nuclei within the syncytiotrophoblast (STB), a multinucleated entity primarily responsible for placental function. Here, we conducted integrated snRNA-seq and snATAC-seq on human placentas from early and late pregnancy. Our findings demonstrate the dynamic heterogeneity and developmental trajectories of STB nuclei and their presence in human trophoblast stem cells (hTSCs)-derived STB. Furthermore, we identified transcription factor (TF) motifs that are biased towards diverse STB nuclear lineages through their associated gene regulatory networks. The role of these TFs in STB differentiation were confirmed in the hTSCs- and trophoblast organoid-derived STB. Together, our data provide valuable insights into the heterogeneity of human STB and represents a valuable resource for interpreting its associated pregnancy complications.
Project description:The human placenta plays vital roles in ensuring a successful pregnancy. Despite the growing body of knowledge about its cellular compositions and functions, however, there has been limited research on the heterogeneity of the billions of nuclei within the syncytiotrophoblast (STB), a multinucleated entity primarily responsible for placental function. Here, we conducted integrated snRNA-seq and snATAC-seq on human placentas from early and late pregnancy. Our findings demonstrate the dynamic heterogeneity and developmental trajectories of STB nuclei and their presence in human trophoblast stem cells (hTSCs)-derived STB. Furthermore, we identified transcription factor (TF) motifs that are biased towards diverse STB nuclear lineages through their associated gene regulatory networks. The role of these TFs in STB differentiation were confirmed in the hTSCs- and trophoblast organoid-derived STB. Together, our data provide valuable insights into the heterogeneity of human STB and represents a valuable resource for interpreting its associated pregnancy complications.
Project description:We reveal that STB which differentiated from hTSCs could recapitulate morphogenetic events that physiologically occur during human embryo implantation. STB could also recapitulate the genetic signature of trophoblast differentiation during implantation. It will provide a reliable model to investigate the syncytialization of trophoblast during implantation. Our discovery was potentially valuable in advancing not only our current understanding of implant progression but also paying the way to investigate recurrent implantation failure.
Project description:The placental DNA methylation landscape is unique, with widespread partially methylated domains (PMDs) and hundreds of placental-specific imprinted domains. Furthermore, the placental ‘methylome’ has been the focus of extensive study for links with pregnancy complications. Human trophoblast stem cells (hTSCs) offer exciting potential for functional epigenetic studies; however, whether the hTSC epigenome recapitulates primary cytotrophoblast, remains poorly described. In this study, we demonstrate that hTSCs exhibit an atypical methylome, with DNA methylation present over transcribed gene bodies but a complete loss of placental PMDs. Using single-cell RNA-seq from human embryogenesis, hTSCs display a notable absence of DNMT3L expression. Ectopic expression of DNMT3L in hTSCs restored placental PMDs. DNMT3L-expressing hTSCs showed comparable stemness but failed to syncytialise in organoid culture, associated with hypermethylation of STB transcription factor motifs. These findings reveal that DNMT3L is essential in establishing the human placental methylome and that DNMT3L downregulation is necessary for successful trophoblast differentiation.
Project description:The placental DNA methylation landscape is unique, with widespread partially methylated domains (PMDs) and hundreds of placental-specific imprinted domains. Furthermore, the placental ‘methylome’ has been the focus of extensive study for links with pregnancy complications. Human trophoblast stem cells (hTSCs) offer exciting potential for functional epigenetic studies; however, whether the hTSC epigenome recapitulates primary cytotrophoblast, remains poorly described. In this study, we demonstrate that hTSCs exhibit an atypical methylome, with DNA methylation present over transcribed gene bodies but a complete loss of placental PMDs. Using single-cell RNA-seq from human embryogenesis, hTSCs display a notable absence of DNMT3L expression. Ectopic expression of DNMT3L in hTSCs restored placental PMDs. DNMT3L-expressing hTSCs showed comparable stemness but failed to syncytialise in organoid culture, associated with hypermethylation of STB transcription factor motifs. These findings reveal that DNMT3L is essential in establishing the human placental methylome and that DNMT3L downregulation is necessary for successful trophoblast differentiation.
Project description:The placental DNA methylation landscape is unique, with widespread partially methylated domains (PMDs) and hundreds of placental-specific imprinted domains. Furthermore, the placental ‘methylome’ has been the focus of extensive study for links with pregnancy complications. Human trophoblast stem cells (hTSCs) offer exciting potential for functional epigenetic studies; however, whether the hTSC epigenome recapitulates primary cytotrophoblast, remains poorly described. In this study, we demonstrate that hTSCs exhibit an atypical methylome, with DNA methylation present over transcribed gene bodies but a complete loss of placental PMDs. Using single-cell RNA-seq from human embryogenesis, hTSCs display a notable absence of DNMT3L expression. Ectopic expression of DNMT3L in hTSCs restored placental PMDs. DNMT3L-expressing hTSCs showed comparable stemness but failed to syncytialise in organoid culture, associated with hypermethylation of STB transcription factor motifs. These findings reveal that DNMT3L is essential in establishing the human placental methylome and that DNMT3L downregulation is necessary for successful trophoblast differentiation.
Project description:This dataset comprises the gene expression profiles of human trophoblast stem cells (hTSCs) and HTR-8/SVneo cells under WT and MYBL2 knockdown conditions. RNA sequencing (RNA-seq) was conducted to examine the effects of MYBL2 depletion on gene expression, with the goal of elucidating its role in trophoblast function, including stemness maintenance, differentiation, and invasion. This dataset offers valuable insights into the molecular mechanisms governed by MYBL2 in trophoblast biology and its potential relevance to pregnancy-related disorders.
Project description:Multinucleated syncytiotrophoblasts (STBs), which are in direct contact with maternal blood, constitute the maternal-fetal interface critical for nutrient allocation, hormone production and immunological modulation during pregnancy. However, the genetic and epigenetic regulatory mechanisms governing trophoblast syncytialization remain largely elusive. We delineate that endogenous retroviruses (ERVs), which have been exapted as regulatory sequences for specific functional adaptations in placenta, profoundly rewire transcriptional program of trophoblast syncytialization. Here, we first determined dynamic bivalent ERV-derived enhancers with dual occupancy of H3K9me3 and H3K27ac in human trophoblast stem cells (hTSCs), which emerge as cell specific regulators of gene expression with markedly resolved H3K9me3 during differentiation towards STBs. Of note, bivalent enhancers derived from the Simiiformes-specific MER50 transposons were linked to a cluster of STB-specific genes. Importantly, depletions of MER50 elements adjacent to several STB genes, including MFSD2A, TNFAIP2 and RAI14, significantly attenuated their expression concomitant to dysregulated syncytium formation. Together, we propose that ERV-derived enhancers, MER50 specifically, fine-tune the transcriptional program accounting for human trophoblast syncytialization, which sheds light on novel epigenetic regulatory mechanisms underlying placental development.
Project description:Multinucleated syncytiotrophoblasts (STBs), which are in direct contact with maternal blood, constitute the maternal-fetal interface critical for nutrient allocation, hormone production and immunological modulation during pregnancy. However, the genetic and epigenetic regulatory mechanisms governing trophoblast syncytialization remain largely elusive. We delineate that endogenous retroviruses (ERVs), which have been exapted as regulatory sequences for specific functional adaptations in placenta, profoundly rewire transcriptional program of trophoblast syncytialization. Here, we first determined dynamic bivalent ERV-derived enhancers with dual occupancy of H3K9me3 and H3K27ac in human trophoblast stem cells (hTSCs), which emerge as cell specific regulators of gene expression with markedly resolved H3K9me3 during differentiation towards STBs. Of note, bivalent enhancers derived from the Simiiformes-specific MER50 transposons were linked to a cluster of STB-specific genes. Importantly, depletions of MER50 elements adjacent to several STB genes, including MFSD2A, TNFAIP2 and RAI14, significantly attenuated their expression concomitant to dysregulated syncytium formation. Together, we propose that ERV-derived enhancers, MER50 specifically, fine-tune the transcriptional program accounting for human trophoblast syncytialization, which sheds light on novel epigenetic regulatory mechanisms underlying placental development.
Project description:The outer surface of chorionic villi in the human placenta consists of a single multinucleated cell called the syncytiotrophoblast (STB). The unique cellular ultrastructure of the STB presents challenges in deciphering its gene expression signature at the single-cell level, as the STB contains billions of nuclei in a single cell. There are many gaps in understanding the molecular mechanisms and developmental trajectories involved in STB formation and differentiation. To identify the underlying control of the STB, we performed comparative single nucleus (SN) and single cell (SC) RNA sequencing on placental tissue and tissue-derived trophoblast organoids (TOs). We found that SN was essential to capture the STB population from both tissue and TOs. Differential gene expression and pseudotime analysis of TO-derived STB identified three distinct nuclear subtypes reminiscent of those recently identified in vivo. These included a juvenile nuclear population that exhibited both CTB and STB marker expression, a population enriched in genes involved in oxygen sensing, and finally a subtype enriched in transport and GTPase signaling molecules. Notably, suspension culture conditions of TOs that restore the native orientation of the STB (STBout) showed elevated expression of canonical STB markers and pregnancy hormones, along with a greater proportion of the STB nucleus subtype specializing in transport and GTPase signaling, compared to those cultivated with an inverted STB polarity (STBin). Gene regulatory analysis identified novel markers of STB differentiation conserved in tissue and TOs, including the chromatin remodeler RYBP, that exhibited STB-specific RNA and protein expression. CRISPR/Cas9 knock out of RYBP in STBin TOs did not affect cell-cell fusion, but bulk sequencing demonstrates the downregulation of the pregnancy hormone CSH1 and upregulation of many genes that define the oxygen sensing STB nuclear subtype. Finally, we compared STB gene expression signatures amongst first trimester tissue, full-term tissue, and TOs, identifying many commonalities but also notable variability across each sample type. This indicates that STB gene expression is responsive to its environmental context. Our findings emphasize the utility of TOs to accurately model STB differentiation and the distinct nuclear subtypes observed in vivo, offering a versatile platform for unraveling the molecular mechanisms governing STB functions in placental biology and disease. The processed datasets can be visualized online at https://gladfelterlab.shinyapps.io/PlacentaRNAsequencing/.