Project description:The aim of the experiment was to compare newly defined CD44Neg, CD44LoKitNeg, CD44LoKitPos and CD44High populations from mouse Aorta-Gonad-Mesonephros (AGM) region
Project description:The aim of this experiment was to compare by single-cell RNA sequencing the aorta-gonad-mesonephros (AGM) region and yolk sac (YS), the two major sites of embryonic hematopoietic, between 9.5 and 11.5 days of mouse embryonic development.
Project description:Hematopoietic stem cells (HSCs) are at the basis of the hematopoietic hierarchy. Their ability to self-renew and differentiate is strictly controlled by molecular signals produced by their surrounding micorenvironments composed of stromal cells. HSCs first emerge in the AGM (Aorta Gonads Mesonephros) region, amplify in the fetal liver (FL) and are maintained in the adult bone marrow (BM). To further characterize the molecular program of the HSC niches, we have compared the global transcriptome of HSC-supportive and non-supportive stromal clones established from the AGM, FL and BM. Hematopoietic stem cells (HSCs) are at the basis of the hematopoietic hierarchy. Their ability to self-renew and differentiate is strictly controlled by molecular signals produced by their surrounding micorenvironments composed of stromal cells. HSCs first emerge in the AGM (Aorta Gonads Mesonephros) region, amplify in the fetal liver (FL) and are maintained in the adult bone marrow (BM). To further characterize the molecular program of the HSC niches, we have compared the global transcriptome of HSC-supportive line from Fetal Calvaria (OP9) and non-supportive stromal clones from fetal liver (BFC). Hematopoietic stem cells (HSCs) are at the basis of the hematopoietic hierarchy. Their ability to self-renew and differentiate is strictly controlled by molecular signals produced by their surrounding micorenvironments composed of stromal cells. HSCs first emerge in the AGM (Aorta Gonads Mesonephros) region, amplify in the fetal liver (FL) and are maintained in the adult bone marrow (BM). To further characterize the molecular program of the HSC niches, we have compared the global transcriptome of HSC-supportive and non-supportive stromal clones established from fetal liver. We took advantage of stromal clones established from the AGM, FL and BM and tested for their ability to support or not HSCs ex vivo. RNA were extracted from confluent stromal cultures or sorted cells and used for hybridization of Affymetrix (mouse gene 1.0 ST) microarrays.
Project description:The hematopoietic stem cells (HSCs) arise from hemogenic endothelial cells (HECs) in the para-aortic splanchnopleure (P-Sp)/aorta-gonad-mesonephros (AGM) region of mouse embryos. HECs differentiate into HSC precursors and blood progenitors and form intra-aortic hematopoietic clusters (IAHCs) in the aorta. To identify HECs in distinction from endothelial cells, we performed single-cell RNA-seq analysis of cells isolated from the dorsal aorta and its surrounding tissues at E9.5. We found the population of HECs in the arterial endothelial cell cluster. Therefore, our data might elucidate the mechanism of HEC development.
Project description:Hematopoietic Stem Cells (HSC) are originated during embryonic development from endothelial-like cells located in the ventral side of the dorsal aorta around day E10-12 of murine development. This region is called AGM for Aorta/Gonad/Mesonephros refering to the tissues around the hemogenic aorta. Cells that emerge from the endothelium and show hematopoietic traits can be distinguished by the expression of the c-kit receptor and finally acquire the CD45 marker. The effect of Notch activation by each one of the ligands has been tested on c-kit+ and ckit- cells from the endothelium of the E11.5 AGM . Incubations with stromal cell lines exposed the cells to high levels of ligand and induced changes in the transcriptome of these cells.
Project description:We profile the transcriptional landscape of mouse fetal placenta and identify four distinct types of haematopoietic stem/progenitor cells (HSPCs) during mid-gestation using single-cell RNA sequencing. We experimentally validate and uncover that a subpopulation of placental endothelial cells exhibits hemogenic endothelial (HE) potential and shares transcriptional features with HE cells in the aorta-gonad-mesonephros (AGM) region.
Project description:Hematopoietic Stem Cells (HSC) are originated during embryonic development from endothelial-like cells located in the ventral side of the dorsal aorta around day E10-12 of murine development. This region is called AGM for Aorta/Gonad/Mesonephros refering to the tissues around the hemogenic aorta. Hematopoiesis depends on the Notch pathway and the identification of Notch-targets is important for the understanding of blood origin. Hematopoietic Stem Cells (HSCs) specification occurs in the embryonic aorta and requires Notch activation, however which are the elements regulated by Notch that control this process are mainly unknown. Here, we took a genome-wide approach to identify putative direct Notch targets by precipitating the chromatin that binds to the Notch partner RBPj in the Aorta-Gonad-Mesonephros (AGM) tissue from E11.5 mouse embryos. This assay revealed 701 gene promoter regions as candidates to be regulated by Notch in the AGM. Chromatin was obtained from a pool of 40 dissected AGMs at E11.5. Chromatin immunoprecipitation (ChIP) was performed as previously described (Aguilera et al, PNAS 2004) with minor modifications. In brief, cross-linked chromatin was sonicated for 10 minutes, medium-power, 0.5-interval; with a Bioruptor (Diagenode) and precipitated with anti-RBPJ (Chu and Bresnick, 2004). After crosslinkage reversal, DNA was used as a template for PCR or for array hybridization. Mouse promoter chip on chip microarray SET (Agilent) was used to identify RBPj targets. It covers 70,000 best identified gene regions with a-5.5 kb to + 2.5 kb range, and has on average 25 probes per gene with an average probe to probe distance of 200 bp. The ChIP-on-chip was performed with dye swaps and one IgG control was brought along. Enrichment analysis was done by comparing the precipitation normalized dye swap signal with input control signal.
Project description:Hematopoietic Stem Cells (HSC) are originated during embryonic development from endothelial-like cells located in the ventral side of the dorsal aorta around day E10-12 of murine development. This region is called AGM for Aorta/Gonad/Mesonephros refering to the tissues around the hemogenic aorta. Hematopoiesis depends on the Notch pathway and the identification of Notch-targets is important for the understanding of blood origin.
Project description:Hematopoietic stem cells (HSC) are generated from specialized endothelial cells of the embryonic aorta. Previously, inflammatory factors have been implicated in regulating mouse HSC development, but it is unclear what cells in the embryonic aorta-gonad- mesonephros (AGM) microenvironment produce these factors. In the adult, macrophages play both pro- and anti-inflammatory roles. We sought to examine whether macrophages or other hematopoietic cells found in the embryo prior to HSC generation are involved in the AGM HSC-generative microenvironment. Our CyTOF results indicate two abundant myeloid cell types - mannose-receptor positive AGM- associated macrophages (AGM-aM) and mannose-receptor negative macrophages/progenitors. We show that the appearance of macrophages in the AGM is dependent on CX3CR1. AGM-aM express a pro-inflammatory signature, localize to the embryonic aorta and dynamically interact with nascent and emerging intra-aortic hematopoietic cells (IAHC). Importantly, upon macrophage depletion, no adult- repopulating HSCs are detected, thus implicating unique pro-inflammatory AGM- associated macrophages in regulating the embryonic development of HSCs.