Project description:Purpose: The goal of this study is to identify and characterize human hematopoietic mesoderm. Methods: APLNR+ mesoderm cells derived from hESCs (H1) were sorted and collected for single cell RNA sequencing after hematopoietic differentiation.
Project description:Genome wide DNA methylation profiling of hESC-derived mesothelium (MesoT), hESCs and hESC-derived splanchnic mesoderm (SplM) compared to primary human tissue samples. The Illumina Infinium HumanMethylation450 BeadChip kit was used to obtain DNA methylation profiles across approximately 450,000 methylation sites. Samples include 2 WA09 hESCs, 2 hESC-derived splanchnic mesoderm and 3 hESC-derived mesothelium replicates.
Project description:The realization of human embryonic stem cells (hESC) as a model for human developmental hematopoiesis and potential cell replacement strategies relies on an improved understanding of the extrinsic and intrinsic factors regulating hematopoietic-specific hESC differentiation. Mesenchymal stem cells (hMSCs) are multipotent cells of mesodermal origin that form part of hematopoietic stem cell niches and have an important role in the regulation of hematopoiesis through production of secreted factors and/or cell-to-cell interactions. We have previously shown that hESCs may be successfully maintained feeder-free using hMSC-conditioned media (MSC-CM). Here, we hypothesized that hESCs maintained in MSC-CM may be more prone to differentiation towards hematopoietic lineage than hESCs grown in standard human foreskin fibroblast (HFF)-conditioned media (HFF-CM). We report that specification into hemogenic progenitors and subsequent hematopoietic differentiation and clonogenic progenitor capacity is robustly enhanced in hESC lines maintained in MSC-CM. Interestingly, co-culture of hESCs on hMSCs fully abrogates hematopoietic specification of hESCs suggesting that the improved hematopoietic differentiation is mediated by MSC-secreted factors rather than by MSC-hESC physical interactions. To investigate the molecular mechanism involved in this process, we analyzed global (LINE-1) methylation and genome-wide promoter DNA methylation. Human ESCs grown in MSC-CM showed a decrease of 20% in global DNA methylation and a promoter DNA methylation signature consisting in 45 genes commonly hypomethylated and 102 genes frequently hypermethylated. Our data indicate that maintenance of hESCs in MSC-CM robustly augments hematopoietic specification and that the process seems mediated by MSC-secreted factors conferring a DNA methylation signature to undifferentiated hESCs which may influence further predisposition towards hematopoietic specification. Total DNA isolated by standard procedures from human embryonic stem cells (hESC) cultured in different conditioned media
Project description:The realization of human embryonic stem cells (hESC) as a model for human developmental hematopoiesis and potential cell replacement strategies relies on an improved understanding of the extrinsic and intrinsic factors regulating hematopoietic-specific hESC differentiation. Mesenchymal stem cells (hMSCs) are multipotent cells of mesodermal origin that form part of hematopoietic stem cell niches and have an important role in the regulation of hematopoiesis through production of secreted factors and/or cell-to-cell interactions. We have previously shown that hESCs may be successfully maintained feeder-free using hMSC-conditioned media (MSC-CM). Here, we hypothesized that hESCs maintained in MSC-CM may be more prone to differentiation towards hematopoietic lineage than hESCs grown in standard human foreskin fibroblast (HFF)-conditioned media (HFF-CM). We report that specification into hemogenic progenitors and subsequent hematopoietic differentiation and clonogenic progenitor capacity is robustly enhanced in hESC lines maintained in MSC-CM. Interestingly, co-culture of hESCs on hMSCs fully abrogates hematopoietic specification of hESCs suggesting that the improved hematopoietic differentiation is mediated by MSC-secreted factors rather than by MSC-hESC physical interactions. To investigate the molecular mechanism involved in this process, we analyzed global (LINE-1) methylation and genome-wide promoter DNA methylation. Human ESCs grown in MSC-CM showed a decrease of 20% in global DNA methylation and a promoter DNA methylation signature consisting in 45 genes commonly hypomethylated and 102 genes frequently hypermethylated. Our data indicate that maintenance of hESCs in MSC-CM robustly augments hematopoietic specification and that the process seems mediated by MSC-secreted factors conferring a DNA methylation signature to undifferentiated hESCs which may influence further predisposition towards hematopoietic specification.
Project description:In vertebrates, GATA2 is a master regulator of hematopoiesis and is expressed throughout embryo development and in adult life. Although the essential role of GATA2 in mouse hematopoiesis is well established, its involvement during early human hematopoietic development is not clear. By combining time-controlled overexpression of GATA2 with genetic knockout experiments, we found that GATA2, at the mesoderm specification stage, promotes the generation of hemogenic endothelial progenitors and their further differentiation to hematopoietic progenitor cells, and negatively regulates cardiac differentiation. Surprisingly, genome-wide transcriptional and chromatin immunoprecipitation analysis showed that GATA2 bound preferentially to regulatory regions, and repressed the expression of cardiac development-related genes. By contrast, genes important for hematopoietic differentiation were upregulated by GATA2 in a mostly indirect manner. Collectively, our data reveal a hitherto unrecognized role of GATA2 as repressor of cardiac fates, and highlight the importance of coordinating the specification and repression of alternative cell fates.
Project description:Purpose:hESCs hematopoietic differentiation recapitulates embryonic hematopoiesis in vivo and occurs through three main stages: mesoderm commitment, hemogenic endothelium (HE) formation and hematopoietic specification. The goal of this study are to increase the understanding of hESCs hematopoietic differentiation process and its regulatory mechanism. Methods: hESC samples were collected through flow cytometry sorting.mRNA profiles of this samples were generated by deep sequencing using Illumina GAIIx. The sequence reads that passed quality filters were analyzed at the transcript isoform level with two methods: Burrows–Wheeler Aligner (BWA) followed by ANOVA (ANOVA) and TopHat followed by Cufflinks. qRT–PCR validation was performed using TaqMan and SYBR Green assays Conclusions: Compared with other three populations, 57 cell surface markers were highly enriched in CD31+CD34+ endothelial cells.
Project description:In vertebrates, GATA2 is a master regulator of hematopoiesis and is expressed throughout embryo development and in adult life. Although the essential role of GATA2 for the onset of mouse hematopoiesis is well established, its involvement during early human hematopoietic development is not clear. By combining time-controlled overexpression of GATA2 with genetic knockout experiments, we found that GATA2, at the mesoderm specification stage, promotes the generation of hemogenic progenitors and their further differentiation to hematopoietic progenitor cells, while negatively regulating cardiac differentiation. Surprisingly, genome-wide transcriptional and chromatin immunoprecipitation analysis showed that GATA2 bound preferentially to regulatory regions, and repressed the expression of cardiac development-related genes. By contrast, genes important for hematopoietic differentiation were upregulated by GATA2 in a mostly indirect manner. Collectively, our data reveal a hitherto unrecognized role of GATA2 as a direct repressor of cardiac fates, and highlight the importance of coordinating the specification and repression of alternative cell fates.