Gene expression in haematopoietic stem and progenitor cells from Gata1-EGFP reporter mouse bone marrow
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ABSTRACT: Haematopoietic stem cells can differentiate into all blood cell types. In this process, cells become progressively restricted to a single cell type. The order in which differentiating cells loose lineage potential, and the prospective isolation of cells with a defined potential remains a long-standing question. We performed gene expression analysis of haematopoietic cells from Gata1-EGFP reporter mice, leading to a model for hematopoiesis where the initial lineage decision consists of a separation of erythroid/megakaryocyte/mast cell/eosinophil potential from lymphopoietic/monocyte/neutrophil potential
Project description:Haematopoietic stem cells can differentiate into all blood cell types. In this process, cells become progressively restricted to a single cell type. The order in which differentiating cells loose lineage potential, and the prospective isolation of cells with a defined potential remains a long-standing question. We performed gene expression analysis of haematopoietic cells from Gata1-EGFP reporter mice, leading to a model for hematopoiesis where the initial lineage decision consists of a separation of erythroid/megakaryocyte/mast cell/eosinophil potential from lymphopoietic/monocyte/neutrophil potential RNA was isolated from HSC EGFP-, HSC EGFP+, LMPP, CLP, preGM EGFP-, preGM EGFP+, GMP EGFP-, GMP EGFP+ and preMegE cells with the QIAGEN RNeasy Micro Kit.
Project description:Haematopoietic stem cells can differentiate into all blood cell types. In this process, cells become progressively restricted to a single cell type. The order in which differentiating cells loose lineage potential, and the prospective isolation of cells with a defined potential remains a long-standing question. We performed gene expression analysis of haematopoietic cells from Gata1-EGFP reporter mice, leading to a model for hematopoiesis where the initial lineage decision consists of a seperation of erythroid/megakaryocyte/mast cell/eosinophil potential from lymphopoietic/monocyte/neutrophil potential Find unbiased heterogeneity in the preGM hematopoietic progenitor population
Project description:Haematopoietic stem cells can differentiate into all blood cell types. In this process, cells become progressively restricted to a single cell type. The order in which differentiating cells loose lineage potential, and the prospective isolation of cells with a defined potential remains a long-standing question. We performed gene expression analysis of haematopoietic cells from Gata1-EGFP reporter mice, leading to a model for hematopoiesis where the initial lineage decision consists of a seperation of erythroid/megakaryocyte/mast cell/eosinophil potential from lymphopoietic/monocyte/neutrophil potential
Project description:Haematopoietic stem cells (HSC) and multipotent progenitor cells (MPP) generate all cells of the blood system, although cellular heterogeneity and bias in lineage potential have been observed. Here, we examined whether lineage-specific transcription factors, such as the B-lineage determinant EBF1, establish lineage bias in early progenitors. We detect low level EBF1 expression in myeloid-biased MPP3 and lymphoid-biased MPP4 cells, and show that Ebf1-deficient animals display reduced HSC quiescence and repopulation capacity, enhanced myelopoiesis and enhanced myeloid differentiation potential of MPP3 and MPP4 cells. Bulk and single-cell RNA-seq analysis revealed a CEBPa-driven myeloid transcriptome in Ebf1-deficient progenitors, and we find that EBF1 binds and potentially antagonizes the haematopoietic Cebpa enhancer. In MPP3 cells, EBF1 additionally primes enhancers associated with B-lymphoid genes that gain expression in common lymphoid progenitors. Thus, our study identifies EBF1 as an important determinant in regulating the balance of myeloid versus lymphoid potential in the earliest hematopoietic progenitors.
Project description:Haematopoietic stem cells (HSC) and multipotent progenitor cells (MPP) generate all cells of the blood system, although cellular heterogeneity and bias in lineage potential have been observed. Here, we examined whether lineage-specific transcription factors, such as the B-lineage determinant EBF1, establish lineage bias in early progenitors. We detect low level EBF1 expression in myeloid-biased MPP3 and lymphoid-biased MPP4 cells, and show that Ebf1-deficient animals display reduced HSC quiescence and repopulation capacity, enhanced myelopoiesis and enhanced myeloid differentiation potential of MPP3 and MPP4 cells. Bulk and single-cell RNA-seq analysis revealed a CEBPa-driven myeloid transcriptome in Ebf1-deficient progenitors, and we find that EBF1 binds and potentially antagonizes the haematopoietic Cebpa enhancer. In MPP3 cells, EBF1 additionally primes enhancers associated with B-lymphoid genes that gain expression in common lymphoid progenitors. Thus, our study identifies EBF1 as an important determinant in regulating the balance of myeloid versus lymphoid potential in the earliest hematopoietic progenitors.
Project description:Haematopoietic stem cells (HSC) and multipotent progenitor cells (MPP) generate all cells of the blood system, although cellular heterogeneity and bias in lineage potential have been observed. Here, we examined whether lineage-specific transcription factors, such as the B-lineage determinant EBF1, establish lineage bias in early progenitors. We detect low level EBF1 expression in myeloid-biased MPP3 and lymphoid-biased MPP4 cells, and show that Ebf1-deficient animals display reduced HSC quiescence and repopulation capacity, enhanced myelopoiesis and enhanced myeloid differentiation potential of MPP3 and MPP4 cells. Bulk and single-cell RNA-seq analysis revealed a CEBPa-driven myeloid transcriptome in Ebf1-deficient progenitors, and we find that EBF1 binds and potentially antagonizes the haematopoietic Cebpa enhancer. In MPP3 cells, EBF1 additionally primes enhancers associated with B-lymphoid genes that gain expression in common lymphoid progenitors. Thus, our study identifies EBF1 as an important determinant in regulating the balance of myeloid versus lymphoid potential in the earliest hematopoietic progenitors.
Project description:The underlying mechanisms which are responsible and govern early haematopoietic differentiation during development are poorly understood. Gene expression comparison between pluripotent human embryonic stem cells and earliest haematopoietic progenitors may reveal novel transcripts and pathways and provide crucial insight into early haematopoietic lineage specification and development. Understanding of transcriptional cues that direct differentiation of human embryonic stem cells (hESC) to defined and functional cell types is essential for their future clinical applications. In this study we have undertaken a comparative transcriptional approach of haematopoietic progenitors derived from hESC at various stages of a feeder and serum free differentiation method and have shown that the largest transcriptional changes occur during the first four days of differentiation. Data mining based on molecular function pointed to RhoGTPase signalling as key regulator of this differentiation. Inhibition of this pathway using a chemical inhibitor (Y26732) resulted in a significant downregulation of haematopoietic progenitors throughout the differentiation window, thus uncovering a previously unappreciated role for RhoGTPase signalling in differentiation of hESC to haematopoietic lineages. There are a total of 4 samples within this microarray experiment with 2 biological replicates for each sample. Pluripotent human embryonic stem cells (day 0) underwent haematopoietic differentiation and at various stages of development (day 4, day 6, day8) differentiated cells were FACS sorted for two key haemangioblast markers, CD31 and KDR.
Project description:The underlying mechanisms which are responsible and govern early haematopoietic differentiation during development are poorly understood. Gene expression comparison between pluripotent human embryonic stem cells and earliest haematopoietic progenitors may reveal novel transcripts and pathways and provide crucial insight into early haematopoietic lineage specification and development. Understanding of transcriptional cues that direct differentiation of human embryonic stem cells (hESC) to defined and functional cell types is essential for their future clinical applications. In this study we have undertaken a comparative transcriptional approach of haematopoietic progenitors derived from hESC at various stages of a feeder and serum free differentiation method and have shown that the largest transcriptional changes occur during the first four days of differentiation. Data mining based on molecular function pointed to RhoGTPase signalling as key regulator of this differentiation. Inhibition of this pathway using a chemical inhibitor (Y26732) resulted in a significant downregulation of haematopoietic progenitors throughout the differentiation window, thus uncovering a previously unappreciated role for RhoGTPase signalling in differentiation of hESC to haematopoietic lineages.
Project description:N6-methyladenosine (m6A) is an abundant modification on mRNA, and plays critical functions in various cellular processes, including cell fate determination and lineage transition. However, the landscape and dynamics of m6A modification in haematopoietic system remain unknown. Here, we delineate a comprehensive m6A landscape across haematopoietic hierarchy and uncover that IGF2BP2 is required for preserving haematopoietic stem cells (HSCs) function. Our data reveal a marked cell-type- and haematopoietic-lineage-specific m6A landscape. Intriguingly, most m6A modifications arise in the early stat of haematopoiesis, and are critical in defining cellular states of HSCs. Moreover, m6A modification is the major factor in determining mRNA abundance in HSCs. Importantly, we find that higher expression of m6A reader IGF2BP2 is critical in controlling gene expression states and the functional maintenance of HSCs. IGF2BP2 deficiency induces apoptosis and quiescence loss, and substantially impairs the reconstitution capacity of HSCs. In addition, deletion of IGF2BP2 increases the mitochondrial activity of HSCs. Mechanistically, IGF2BP2 stabilizes Bmi1 mRNA in an m6A-dependent manner, which represses the expression of mitochondria-related genes. Collectively, our results present a fascinating portrait of m6A modification during haematopoiesis, and uncover a key role of IGF2BP2 in maintaining HSCs function by regulating Bmi1 stability and restraining mitochondrial activity.
Project description:Developmental pathways that orchestrate the fleeting transition of endothelial cells into haematopoietic stem cells remain undefined. Here we demonstrate a tractable approach for fully reprogramming adult mouse endothelial cells to haematopoietic stem cells (rEC-HSCs) through transient expression of the transcription-factor-encoding genes Fosb, Gfi1, Runx1, and Spi1 (collectively denoted hereafter as FGRS) and vascular-niche-derived angiocrine factors. The induction phase (days 0-8) of conversion is initiated by expression of FGRS in mature endothelial cells, which results in endogenous Runx1 expression. During the specification phase (days 8-20), RUNX1+ FGRS-transduced endothelial cells commit to a haematopoietic fate, yielding rEC-HSCs that no longer require FGRS expression. The vascular niche drives a robust self-renewal and expansion phase of rEC-HSCs (days 20-28). rEC-HSCs have a transcriptome and long-term self-renewal capacity similar to those of adult haematopoietic stem cells, and can be used for clonal engraftment and serial primary and secondary multi-lineage reconstitution, including antigen-dependent adaptive immune function. Inhibition of TGF? and CXCR7 or activation of BMP and CXCR4 signalling enhanced generation of rEC-HSCs. Pluripotency-independent conversion of endothelial cells into autologous authentic engraftable haematopoietic stem cells could aid treatment of haematological disorders.