C/EBPa controls acquisition and maintenance of adult hematopoietic stem cell quiescence
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
SUBMITTER: Henry Yang
PROVIDER: E-GEOD-42234 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:To guarantee blood supply throughout adult life hematopoietic stem cells (HSCs) need to carefully balance between self-renewing cell divisions and quiescence. Identification of genes controlling HSC self-renewal is of utmost importance given that HSCs are the only stem cells with broad clinical applications. Transcription factor PU.1 is one of the major regulators of myeloid and lymphoid development. Recent reports suggest that PU.1 mediates its functions via gradual expression level changes rather than binary on/off states. So far, this has not been considered in any study of HSCs and thus, PU.1’s role in HSC function has remained largely unclear. Here we demonstrate using hypomorphic mice with an engineered disruption of an autoregulatory feedback loop that decreased PU.1 levels resulted in loss of key HSC functions, all of which could be fully rescued by restoration of proper PU.1 levels via a human PU.1 transgene. Mechanistically, we found excessive HSC cell divisions and altered expression of cell cycle regulators whose promoter regions were bound by PU.1 in normal HSCs. Adequate PU.1 levels were maintained by a mechanism of direct autoregulation restricted to HSCs through a physical interaction of a -14kb enhancer with the proximal promoter. Our findings identify PU.1 as novel regulator controling the switch between cell division and quiescence in order to prevent exhaustion of HSCs. Given that even moderate level changes greatly impact stem cell function, our data suggest important therapeutic implications for leukemic patients with reduced PU.1 levels. Moreover, we provide first proof, that autoregulation of a transcription factor, PU.1, has a crucial function in vivo. We anticipate that our concept of how autoregulation forms an active chromosomal conformation will impact future research on transcription factor networks regulating stem cell fate. 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.
2011-12-01 | E-GEOD-33031 | biostudies-arrayexpress
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.
2012-11-14 | GSE42234 | GEO
Project description:The transcription factor SOX17 is expressed by fetal, but not adult hematoipoietic stem cells (HSCs), and is required for the maintenance of fetal and neonatal, but not adult, HSCs. In the current study we show that ectopic expression of Sox17 in adult HSCs and transiently reconstituting multipotent progenitors was sufficient to confer increased self-renewal potential and the expression of fetal HSC genes including fetal HSC surface markers. To assess the acute effects of ectopic Sox17 expression on global gene expression in adult HSCs, we performed microarray analysis to compare the gene expression profile of adult Sox17-trangenic and control HSCs after short induction of Sox17-transgene expression. Total RNA were isolated from 5 independent, freshly isolated aliquots of 10,000 HSCs isolated from 8-week old Sox17-transgenic ((tetO)7CMVSox17-IRES-NucEGFP;B6.Cg-Gt(ROSA)26Sortm1(rtTA*M2)Jae/J double transgenic) or littermate control mice that were treated with doxycycline for 5 days to induce transgene expression. Purified RNA was reverse transcribed and amplified using the WT-Ovation™ Pico RNA Amplification system (NuGEN Technologies) following the manufacturer’s instructions. Sense strand cDNA was generated using WT-Ovation™ Exon Module (NuGEN), then fragmented and labeled using the FL-Ovation™ cDNA Biotin Module V2 (NuGEN). 2.5µg of labeled cDNA were hybridized to Affymetrix Mouse Gene ST 1.0 microarrays.
2011-07-14 | E-GEOD-30445 | biostudies-arrayexpress
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.
2016-02-19 | E-MTAB-4034 | biostudies-arrayexpress
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.
2016-05-19 | E-GEOD-67120 | biostudies-arrayexpress
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.
2009-01-15 | E-GEOD-14361 | biostudies-arrayexpress
Project description:FoxM1, a mammalian Forkhead Box M1 protein, is known as a typical proliferation-associated transcription factor that regulates of G1/S and G2/M transition in the proliferating cells. However, the in vivo function of FoxM1 in adult stem cells remains unknown. Here, we found that FoxM1 is highly expressed in hematopoietic stem cells (HSCs) and is essential for maintaining quiescence and self-renewal of HSCs in vivo. FoxM1-deficient mice developed leukopenia, thrombocytopenia and neutropenia with an approximately 6-fold decrease in HSC pool size, which is associated with a failure of G0 cell cycle regulation and increased cell cycling in HSCs. FoxM1 absence did not affect lineage commitment of HSCs and progenitors. However, FoxM1 loss significantly reduced the repopulating capacity and self-renewal of long-term HSC in a cell-autonomous manner. Mechanistically, FoxM1 loss markedly down-regulates the expression of orphan nuclear receptor Nurr1, known to regulate HSC quiescence. We found that FoxM1 directly bound the promoter region of Nurr1 and induced transcriptional activity of Nurr1 promoter in vitro, and forced expression of Nurr1 rescued FoxM1-deletion-induced G0 loss of HSC-enriched population in vitro. Thus, our studies show a previously unrecognized role of FoxM1 as a critical regulator of HSC quiescence and self-renewal by controlling Nurr1-mediated pathways. The Hematopoietic Stem Cells (HSCs) were sorted from FoxM1[fl/fl] and Tie2-Cre FoxM1[fl/fl] mice, then amplified with Ovation Pico WTA System V2 before microarray analysis. There are 3 samples from FoxM1[fl/fl]mice and 3 samples from Tie2-Cre FoxM1[fl/fl] mice.
2015-06-15 | E-GEOD-62360 | biostudies-arrayexpress
Project description:The transcription factor SOX17 is expressed by fetal, but not adult hematoipoietic stem cells (HSCs), and is required for the maintenance of fetal and neonatal, but not adult, HSCs. In the current study we show that ectopic expression of Sox17 in adult HSCs and transiently reconstituting multipotent progenitors was sufficient to confer increased self-renewal potential and the expression of fetal HSC genes including fetal HSC surface markers. To assess the mechanisms by which ectopic Sox17 expression in adult hematopoietic progenitors increased self-renewal potential and conferred fetal HSC properties, we compared the gene expression profiles of E16.5 fetal liver HSCs, young adult bone marrow HSCs, young adult bone marrow CD48+LSK cells, and Sox17-expressing CD48+LSK cells isolated from mice that had been transplanted with MSCV-Sox17-infected bone marrow cells 12 weeks earlier. Total RNA (~5ng) was isolated from 3 independent, freshly isolated aliquots of 10,000 E16.5 fetal liver HSCs, 10,000 fetal liver CD48+LSK cells, 10,000 adult bone marrow HSCs, 10,000 adult bone marrow CD48+LSK cells, 10,000 Sox17-expressing CD48+LSK cells isolated from primary recipients 12 weeks after transplantation of MSCV-Sox17-infected bone marrow cells. Purified RNA was reverse transcribed and amplified using the WT-Ovation™ Pico RNA Amplification system (NuGEN Technologies) following the manufacturer’s instructions. Sense strand cDNA was generated using WT-Ovation™ Exon Module (NuGEN), then fragmented and labeled using the FL-Ovation™ cDNA Biotin Module V2 (NuGEN). 2.5µg of labeled cDNA were hybridized to Affymetrix Mouse Gene ST 1.0 microarrays.
2011-07-14 | E-GEOD-30444 | biostudies-arrayexpress
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.
2015-08-26 | PXD001500 | Pride
Project description:Adult and fetal hematopoietic stem cells (HSCs) display a glycolytic phenotype, which is required for maintenance of stemness; however, whether mitochondrial respiration is required to maintain HSC function is not known. Here we report that loss of the mitochondrial complex III subunit Rieske iron sulfur protein (RISP) in fetal mouse HSCs allows them to proliferate but impairs their differentiation, resulting in anemia and prenatal death. RISP null fetal HSCs displayed impaired respiration resulting in a decreased NAD+/NADH ratio. RISP null fetal HSCs and progenitors exhibited an increase in both DNA and histone methylation concomitant with increases in 2-hydroxyglutarate (2-HG), a metabolite known to inhibit DNA and histone demethylases. RISP inactivation in adult HSCs also impaired respiration resulting in loss of quiescence resulting in severe pancytopenia and lethality. Thus, respiration is dispensable for adult or fetal HSC proliferation, but essential for fetal HSC differentiation and maintenance of adult HSC quiescence.
2017-09-13 | PXD006054 | Pride