RNA from young and aged mouse hematopoietic stem cells
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ABSTRACT: Identification of differentially expressed genes in young (3 month old) versus aged (24 month old) mouse hematopoietic stem cells. Comparison of genes differentially expressed in hematopoietic stem cells of young mice with conditional deletion of mTOR within vascular endothelium.
Project description:In blood, the transcription factor C/EBPa is essential for myeloid differentiation and has been implicated in regulating self-renewal of fetal liver hematopoietic stem cells (HSCs). However, its function in adult HSCs is unknown. Here, using an inducible knockout model, we found that C/EBPa deficient adult HSCs underwent a pronounced expansion with enhanced proliferation, characteristics resembling fetal liver HSCs. Consistently, transcription profiling of C/EBPa deficient HSCs revealed a gene expression program similar to fetal liver HSCs. Moreover we observed that age-specific C/EBPa expression correlated with its inhibitory effect on the HSC cell cycle. Mechanistically, we identified N-Myc as a C/EBPa downstream target. C/EBPa upregulation during HSC transition from an active fetal state to a quiescent adult state was accompanied by down-regulation of N-Myc, and loss of C/EBPa resulted in de-repression of NMyc. Our data establish that C/EBPa acts as a molecular switch between fetal and adult states of HSC in part via transcriptional repression of the proto-oncogene N-Myc. HSCs of Pu.1 knock-in (PU.1ki/ki) mice were used for RNA extraction and hybridization on Affymetrix microarrays. We compared these microarray samples with the corresponding wild type.
Project description:To identify the molecular characterisitics of parallel lineage-biased MPP populations arising from hematopoietic stem cells (HSC) we conducted genome-wide analyses of hematopoietic stem, progenitor and mature myeloid cell populations using Affymetrix Gene ST1.0 arrays. Microarray analysis of 3-5 biological replicates of the indicated hematopoietic populations, isolated by FACS sorting from C57BL/6 mouse BM. Immunophenotypic definitions: Long-term HSC (HSCLT) (Lin-/cKit+/Sca1+/Flk2-/CD48-/CD150+); Short-term HSC (HSCST) (Lin-/cKit+/Sca1+/Flk2-/CD48-/CD150-); MPP2 (Lin-/cKit+/Sca1+/Flk2-/CD48+/CD150+); MPP3 (Lin-/cKit+/Sca1+/Flk2-/CD48+/CD150-); MPP4 (Lin-/cKit+/Sca1+/Flk2+); CMP (Lin-/cKit+/Fc?R-/CD34+); GMP (Lin-/cKit+/Fc?R+/CD34+); Pre-granulocyte (PreGr) (Mac1+/Gr1int); Granulocyte (Gr) (Mac1+/Gr1hi). HSC and GMP samples listed here were also used as controls for our related microarray study GSE48893.
Project description:This SuperSeries is composed of the following subset Series: GSE30444: Retroviral Sox17 over-expression adult hematopoietic stem/progenitor cells microarray GSE30445: Sox17-transgenic hematopoietic stem cell microarray Refer to individual Series
Project description:Murine hematopoietic stem cells were sorted by FACS from C57BL/6 Evi1+/GFP mice. Gene expression profiles of LSKCD41–CD48–CD150+CD34+ cells, LSKCD41–CD48–CD150+CD34–Evi1-GFP– cells, and LSKCD41–CD48–CD150+CD34–Evi1-GFP+ cells were generated.
Project description:Identification of differentially expressed genes in young (3 month old) versus aged (24 month old) mouse bone marrow derived endothelial cells. Comparison of genes differentially expressed in bone marrow derived endothelial cells of young mice with conditional deletion of mTOR within vascular endothelium.
Project description:Although Hematopoietic Stem Cell Transplantation (HSCT) routinely treats hematologic disease, many patients experience adverse outcomes. Understanding the molecular regulation of HSC engraftment is paramount to improving HSCT regimens. Here, we executed a large-scale transplant-based functional screen for novel regulators of HSC repopulation.. Of >50 gene candidates tested, 18 were required for in vivo hematopoietic repopulation and two were detrimental to repopulation, as their loss enhanced this activity. Each Hit was validated in a second screen. Eleven Hits have never before been implicated in HSC biology. We further show that one novel Hit, Foxa3, is required for optimal engraftment as Foxa3-/- bone marrow is defective in both primary and secondary hematopoietic reconstitution. We also present evidence that Foxa3 is a novel pioneer factor in HSC. Each gene identified in our screen is a window into the cellular mechanisms that control hematopoietic reconstitution. Thus, this work represents a resource to the community to better understand these processes 3 FOXA3 KO samples are compared to 3 wt samples
Project description:Infections are associated with extensive consumption of blood platelets representing a high risk for health. How the hematopoietic system coordinates the rapid and efficient regeneration of this particular lineage during such stress scenarios remains unclear. Here we report that the phenotypic hematopoietic stem cell (HSC) compartment contains highly potent megakaryocyte-committed progenitors (hipMkPs), a cell population that shares many features with multipotent HSCs and serves as a lineage-restricted emergency pool for inflammatory insults. Our data show that during homeostasis, hipMkPs are maintained in a primed but quiescent state, thus contributing little to steady-state megakaryopoiesis. Moreover, homeostatic hipMkPs show expression of megakaryocyte lineage priming transcripts for which protein synthesis is suppressed. We demonstrate that acute inflammatory signaling instructs activation of hipMkPs, as well as Mk protein production from pre-existing transcripts and drives a rapid maturation of hipMkPs and other Mk progenitors. This results in an efficient regeneration of platelets that are lost during inflammatory insult. Thus, our study reveals an elegant emergency machinery that counteracts life-threating depletions in the platelet pool during acute inflammation.
Project description:In this study, we use pre-malignant cells from different Cebpa mutant acute myeloid leukemia (AML) models. We have used conditional KO models (CreLoxP) and isolated hematopoietic cells shortly after induction of recombination, in order to look at pre-leukemic cells, which have acquired the first hit, but not yet undergone full malignant transformation. We have sorted granulocyte-macrophage progenitors (GMPs) and the more immature population pre-granulocyte-macrophages (preGMs) from pre-leukemic mice. We analyzed gene-expression profiles in order to find deregulated genes, which make the cells more prone to undergo transformation.
Project description:Maintenance of the blood system is dependent on dormant haematopoietic stem cells (HSCs) with long-term self-renewal capacity. Upon injury these cells are induced to proliferate in order to quickly re-establish homeostasis. The signalling molecules promoting the exit of HSCs out of the dormant stage remain largely unknown. Here we show that in response to treatment of mice with interferon-alpha (IFNα), HSCs efficiently exit G0 and enter an active cell cycle. HSCs respond to IFNα treatment by increased phosphorylation of STAT1 and PKB/Akt, expression of IFNα target genes and up-regulation of stem cell antigen-1 (Sca-1). HSCs lacking either the interferon-α/β receptor (IFNAR), STAT1 or Sca-1 are insensitive to IFNα stimulation, demonstrating that STAT1 and Sca-1 mediate IFNα induced HSC proliferation. Although dormant HSCs are resistant to the anti-proliferative chemotherapeutic agent 5-FU1, HSCs pre-treated (primed) with IFNα and thus induced to proliferate are efficiently eliminated by 5-FU exposure in vivo. Conversely, HSCs chronically activated by IFNα are functionally compromised and are rapidly out competed by non-activatable IFNAR-/- cells in competitive repopulation assays. In summary, while chronic activation of the IFNα pathway in HSCs impairs their function, acute IFNα treatment promotes the proliferation of dormant HSCs in vivo. These data may help to clarify the so far unexplained clinical effects of IFNα on leukemic cells and raise the possibility for novel applications of type I interferons to target cancer stem cells. cDNA microarray analysis was performed on sorted Lin neg, cKit+, CD150+, CD48neg HSCs from IFNα treated (16h after treatment) and untreated (littermate) mice. Per condition 3 independent biological replicates were analysed.