Project description:Definitive hematopoietic stem cells (HSCs) bud off from the hemogenic endothelial cells (HEC) located in the dorsal aorta of the mouse embryo. The maturation of HSCs from HEC occurs through the precursor of HSCs (pre-HSCs) between embryonic day (E) 9.5 and E11.5. To clarify the differentiation process of pre-HSCs, we performed single-cell RNA-seq analysis of cells dissociated from the dorsal aorta and its surrounding tissues and the fetal liver at E10.5 and E11.5. We identified pre-HSCs population generated from an arterial marker-expressing cluster. Thus, our data might be useful to understand the differentiation process of pre-HSCs.
Project description:Hematopoietic stem cell (HSC) generation in the aorta-gonads-mesonephros region requires HSC specification signals from the surrounding microenvironment. In zebrafish, PDGF-B/PDGFRβ signaling controls hematopoietic stem/progenitor cell (HSPC) generation and is required in the HSC specification niche. Little is known about murine HSPC specification in vivo and whether PDGF-B/PDGFRβ is involved. Here we show that PDGFRβ is expressed in distinct perivascular stromal cell layers surrounding the mid-gestation dorsal aorta, and its deletion impairs hematopoiesis. We demonstrate that PDGFRβ+ cells play a dual role in murine hematopoiesis. They act in the aortic niche to support HSPCs, and in addition, PDGFRβ+ embryonic precursors give rise to a subset of HSPCs that persist into adulthood. These findings provide crucial information for the controlled production of these clinically important cells in vitro.
Project description:Hematopoietic stem cell (HSC) generation in the aorta-gonads-mesonephros region requires HSC specification signals from the surrounding microenvironment. In zebrafish, PDGF-B/PDGFRβ signaling controls hematopoietic stem/progenitor cell (HSPC) generation and is required in the HSC specification niche. Little is known about murine HSPC specification in vivo and whether PDGF-B/PDGFRβ is involved. Here we show that PDGFRβ is expressed in distinct perivascular stromal cell layers surrounding the mid-gestation dorsal aorta, and its deletion impairs hematopoiesis. We demonstrate that PDGFRβ+ cells play a dual role in murine hematopoiesis. They act in the aortic niche to support HSPCs, and in addition, PDGFRβ+ embryonic precursors give rise to a subset of HSPCs that persist into adulthood. These findings provide crucial information for the controlled production of these clinically important cells in vitro.
Project description:Human embryonic stem cells (hESCs) offer an important model for investigating the human hematopoietic celldevelopment. Here, we used long serial analysis of gene expression and quantitative real-time PCR to characterize two subsets of primitive hematopoietic cells derived in vitro from hESCs. This revealed differences in their expression of genes associated with lymphoid and myeloid development, cellular biosynthetic processes, and cell cycle regulation. Further comparisons with analogous data for primitive hematopoietic cells isolated from first trimester human fetal liver and newborn cord blood showed a strong similarity between the transcriptomes of the most primitive hESC- and in vivo-derived populations, with the main differences involving genes that regulate HSC development, self-renewal and homing, chromatin remodeling, AP1 transcription complex genes, and non-coding RNAs. These data suggest that primitive hematopoietic cells are generated from hESCs in vitro by processes similar to those operative during human embryogenesis in vivo, although some differences were also detected. Human embryonic stem cells (hESCs) are capable of indefinite self-renewal but can also be induced to undergo a stepwise process of differentiation into a spectrum of recognizable mature blood cell types. However, a clear understanding of the molecular mechanism by which the first hematopoietic stem cells (HSCs) acquire their unique defining properties of self-renewal and repopulating potential is lacking. As a first step towards obtaining the information needed to close this gap, we have undertaken a comparative gene expression analysis of different highly purified primitive human hematopoietic subpopulations (erythroid-megakaryocytic progenitor enriched CD43+CD235a+CD41a+/- cells, mutiplepotent progenitor enriched lin-CD34+CD43+CD45-, and lin-CD34+CD43+CD45+ cells) generated either in vitro from hESCs or in vivo from fetal (human fetal liver lin-CD34+CD38- cells) or neonatal hematopoietic primitive cells (human cord blood lin-CD34+CD38- and lin-CD34+CD38+ cells). This involved preparing a long serial analysis of gene expression (LongSAGE) library from an extracts of each prospectively isolated subpopulation and then sequencing each library to a depth of 200,000 tags.
Project description:Transcriptional profiling of mouse ES cell-derived hemaopoitic cells comparing common primitive-definitive hematopoietic precursors (CD41SP) with definitve hematopoietic progenitor cells (KA45) RNA isolated from two separate experiments was pooled and used for comparison
Project description:Human embryonic stem cells (hESCs) offer an important model for investigating the human hematopoietic celldevelopment. Here, we used long serial analysis of gene expression and quantitative real-time PCR to characterize two subsets of primitive hematopoietic cells derived in vitro from hESCs. This revealed differences in their expression of genes associated with lymphoid and myeloid development, cellular biosynthetic processes, and cell cycle regulation. Further comparisons with analogous data for primitive hematopoietic cells isolated from first trimester human fetal liver and newborn cord blood showed a strong similarity between the transcriptomes of the most primitive hESC- and in vivo-derived populations, with the main differences involving genes that regulate HSC development, self-renewal and homing, chromatin remodeling, AP1 transcription complex genes, and non-coding RNAs. These data suggest that primitive hematopoietic cells are generated from hESCs in vitro by processes similar to those operative during human embryogenesis in vivo, although some differences were also detected.