Tracing the formation of hematopoietic stem cells in mouse embryos by single-cell functional and RNA-Seq analyses [10-cell]
Ontology highlight
ABSTRACT: Hematopoietic stem cells (HSCs) in adult are specified early from the endothelium-derived precursors (e.g., hemogenic endothelium, and pre-HSCs) in mouse mid-gestation embryos, the detailed process, however, is still largely unknown due to their rareness, transience, and current inability to prospectively isolate them efficiently . Here we developed a potent set of surface markers that could capture the earliest emerging HSCs, the CD45- pre-HSCs with high accuracy and purity, as rigorously and functionally verified by single-cell-initiated serial transplantation assays. Then we applied single-cell RNA-Seq technique to analyze five populations related to HSC formation: the CD45- (type 1) and CD45+ (type 2) pre-HSCs as well as endothelial cells in the E11 AGM region; and later mature HSCs in the E12 and E14 fetal livers. Compared to other cell populations, both type 1 and type 2 pre-HSCs have their unique signatures of transcription machinery, transcription factor network, signaling pathway, cell cycle status, metabolism state, and lncRNA expression patterns. Our work paves the way for dissection of the complex molecular mechanisms regulating the step-wise formation of HSCs from endothelial cells, thus informing future efforts on engineering HSCs for clinical application. RNA-Seq of 35 10-cell pooled samples from 5 FACS sorted cell types, i.e., endothelial cells (ECs), T1 and T2 pre-HSCs from E11 AGM region, as well as mature HSCs from E12 and E14 fetal liver
Project description:Haematopoietic stem cells (HSCs) are derived early from embryonic precursor cells, such as haemogenic endothelial cells and pre-HSCs. However, the identity of precursor cells remains elusive due to their rareness, transience, and inability to be isolated efficiently. Here we employed potent surface markers to capture the nascent pre-HSCs at 30% purity, as rigorously validated by single-cell-initiated serial transplantation assay. Then we applied single-cell RNA-Seq technique to analyse five populations closely related to HSC formation: endothelial cells, CD45- and CD45+ pre-HSCs in E11 aorta-gonad-mesonephros (AGM) region, and mature HSCs in E12 and E14 foetal liver. In comparison, the pre-HSCs showed unique features in transcriptional machinery, apoptosis, metabolism state, signalling pathway, transcription factor network, and lncRNA expression pattern. Among signalling pathways enriched in pre-HSCs, the mTOR activation was uncovered indispensable for the emergence of HSCs but not haematopoietic progenitors from endothelial cells in vivo. By comparing with proximal populations without HSC potential, the core molecular signature of pre-HSCs was identified. Collectively, our work paves the way for dissection of complex molecular mechanisms regulating the step-wise generation of HSCs in vivo, informing future efforts to engineer HSCs for clinical application. RNA-Seq of 181 single-cell samples from 8 FACS sorted cell types: 1. endothelial cells (samples E11.0_EC_xxxx. CD31+ VE-cadherin+CD41-CD43-CD45-Ter119-); 2. T1 pre-HSCs (samples E11.0_T1_xxxx. CD31+CD45-CD41low c-Kit+CD201high); 3. T1 CD201- cells (samples E11.0_T1CD201neg_xxxx, CD31+CD45-CD41low c-Kit+CD201low/-) ; 4. T2 pre-HSCs (samples E11.0_T2_35xx. CD31+CD45+c-Kit+CD201high), 5. T2 CD41low (samples E11.0_T2_21xx, E11.0_T2_24xx and E11.0_T2_27xx. CD31+CD45+CD41low); 6. E12 HSCs (samples E12.5_FL_xxxx. Lin-Sca-1+Mac-1lowCD201+); 7. E14 HSCs (samples E14.5_FL_xxxx. CD45+CD150+CD48-CD201+); 8. Adult HSCs (samples Adult_HSC_xxxx. CD45+CD150+CD48-CD201+). ECs, T1 pre-HSCs, T1 CD201- cells, T2 pre-HSCs, T2 CD41low cells were sorted from E11 AGM region. Mature HSCs were sorted from E12 or E14 fetal liver and adult bonemarrow.
Project description:Hematopoietic stem cells (HSCs) in adult are specified early from the endothelium-derived precursors (e.g., hemogenic endothelium, and pre-HSCs) in mouse mid-gestation embryos, the detailed process, however, is still largely unknown due to their rareness, transience, and current inability to prospectively isolate them efficiently . Here we developed a potent set of surface markers that could capture the earliest emerging HSCs, the CD45- pre-HSCs with high accuracy and purity, as rigorously and functionally verified by single-cell-initiated serial transplantation assays. Then we applied single-cell RNA-Seq technique to analyze five populations related to HSC formation: the CD45- (type 1) and CD45+ (type 2) pre-HSCs as well as endothelial cells in the E11 AGM region; and later mature HSCs in the E12 and E14 fetal livers. Compared to other cell populations, both type 1 and type 2 pre-HSCs have their unique signatures of transcription machinery, transcription factor network, signaling pathway, cell cycle status, metabolism state, and lncRNA expression patterns. Our work paves the way for dissection of the complex molecular mechanisms regulating the step-wise formation of HSCs from endothelial cells, thus informing future efforts on engineering HSCs for clinical application.
Project description:Haematopoietic stem cells (HSCs) are derived early from embryonic precursor cells, such as haemogenic endothelial cells and pre-HSCs. However, the identity of precursor cells remains elusive due to their rareness, transience, and inability to be isolated efficiently. Here we employed potent surface markers to capture the nascent pre-HSCs at 30% purity, as rigorously validated by single-cell-initiated serial transplantation assay. Then we applied single-cell RNA-Seq technique to analyse five populations closely related to HSC formation: endothelial cells, CD45- and CD45+ pre-HSCs in E11 aorta-gonad-mesonephros (AGM) region, and mature HSCs in E12 and E14 foetal liver. In comparison, the pre-HSCs showed unique features in transcriptional machinery, apoptosis, metabolism state, signalling pathway, transcription factor network, and lncRNA expression pattern. Among signalling pathways enriched in pre-HSCs, the mTOR activation was uncovered indispensable for the emergence of HSCs but not haematopoietic progenitors from endothelial cells in vivo. By comparing with proximal populations without HSC potential, the core molecular signature of pre-HSCs was identified. Collectively, our work paves the way for dissection of complex molecular mechanisms regulating the step-wise generation of HSCs in vivo, informing future efforts to engineer HSCs for clinical application.
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 and refers 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. AGM regions were obtained from E11.5 embryos by dissection and digested with 0.1% collagenase. Cells were stained with anti-CD31, anti-ckit, anti-CD45 and anti-Ter119 antibodies. Sorting of the CD31+CD45-Ter119- population was performed, and cells were separated into c-kit+ and c-kit-. 3 replicates each of c-kit+ and c-kit- cells.
Project description:The first HSCs are produced in the aorta-gonadmesonephros (AGM) region of the embryo through endothelial to a hematopoietic transition. BMP4 and Hedgehog affect their production/expansion, but it is unknown whether they act to affect the same HSCs. In this study using the BRE GFP reporter mouse strain that identifies BMP/Smad-activated cells, we find that the AGM harbors two types of adult-repopulating HSCs upon explant culture. Embryonic day 11 AGM are dissected and either analyzed directly, or after explant culture in conditions containing BMP/Hedgehog with or without cyclopamine. EC: endothelial enriched (CD31+Kit-); MC: mesenchymal cell enriched (CD31-Kit-); HPSC: hematopoietic progenitor/stem cell enriched; AGM11: E11 fresh AGMs; AGMex: AGM after explant culture; AGMcy: AGM after explant in presence of cyclopamine; CD31p: CD31 positive; CD31n: CD31 negative; KITp: c-Kit positive; KITn: c-Kit negative; BREp: BRE-GFP positive; BREn: BRE-GFP negative
Project description:Hematopoietic stem cells (HSC) has unique characteristic to self-renew and replenish the entire blood system. During development, HSCs originate in the aorta-gonads-mesonephros (AGM), from where they migrate into the fetal liver at E11. Once resided in fetal liver HSC proliferate extensively to make sufficient stem pool for adult life. Around birth, HSC from FL migrate to bone marrow (BM) which is major site of hematopoiesis for whole adult life. In contrast to FL HSC, BM HSC remain quiescence state and give rise to different blood cell type under normal homeostatic condition. It has shown that FL HSCs display significantly faster expansion kinetics when transplanted into lethally irradiate mice, compared with HSCs from adult BM. However, detail molecular mechanism behind the difference in self-renewal potential is not fully understood. Here, we present the genome-wide transcriptome analysis of more proliferative FL HSC compared to quiescent BM HSC using RNA-Seq platform.
Project description:Study of the gene expression patterns of specific cardiac cell populations, including monocytes (CD45+, CD11b+, F4/80-, LyC6+), endothelial cells (CD45-, CD31+), macrophages (CD45+, CD11b+, F4/80+, LyC6-), and fibroblasts (CD45-, GP38+), in response to at-RA and 4-oxo-RA treatments. Female C57BL/6J mice aged 12 weeks were intraperitoneally injected with 30 mg/kg body weight at-RA (Sigma-Aldrich), 30 mg/kg body weight 4-oxo-RA (Sigma-Aldrich), or an equivalent volume of DMSO in phosphate-buffered saline (PBS) as the vehicle control. After 24 hours of injection, the mice were euthanized for analysis.
Project description:We performed lineage tracing experiments using VE-Cadherin-Cre;LoxP-tdTomato mice. In these mice, endothelial cells (ECs) and their progeny are permanently marked by tdTomato fluorescence. We found that a substantial subset of stromal cells is derived from ECs, as indicated by their tdTomato expression. These findings support the notion that endothelial to mesenchymal transition (EndoMT) contributes to hematopoietic bone marrow niche formation in mice. Here we sought to determine the transcriptomic differences between endothelial-derived (tdTomato-positive) and non-endothelial-derived (tdTomato-negative) bone marrow stromal cells (BMSCs) and osteo/chondrolineage progenitor cells (OLCs). Murine niche populations were obtained from collagenased bone fraction of VE-Cadherin-Cre;LoxP-tdTomato mice at 3 weeks (n=2) or 11 weeks (n=2) of age. BMSCs (CD45-TER119-CD31-CD144-SCA-1+ CD51+ cells) and OLCs (CD45-TER119-CD31-CD144-Sca1-CD51+ cells) were FACS-purified and sequenced.
Project description:Single-cell transcriptomic profiling of CD45-CD31+ endothelial cells derived from healthy and psoriatic human skin using the 10x Genomics platform.