scholarly journals The transcription factor Foxm1 is essential for the quiescence and maintenance of hematopoietic stem cells

2015 ◽  
Vol 16 (8) ◽  
pp. 810-818 ◽  
Author(s):  
Yu Hou ◽  
Wen Li ◽  
Yue Sheng ◽  
Liping Li ◽  
Yong Huang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transcription Factor ◽  
Hematopoietic Stem Cells ◽  
Hematopoietic Stem

scholarly journals A Novel, Myeloid Transcription Factor, C/EBPε, Is Upregulated During Granulocytic, But Not Monocytic, Differentiation

Blood ◽  
1997 ◽  
Vol 90 (7) ◽  
pp. 2591-2600 ◽  
Author(s):  
Roberta Morosetti ◽  
Dorothy J. Park ◽  
Alexey M. Chumakov ◽  
Isabelle Grillier ◽  
Masaaki Shiohara ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transcription Factor ◽  
Hematopoietic Stem Cells ◽  
Cell Line ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Leukemia Cell ◽  
Rt Pcr ◽  
Hematopoietic Stem ◽  
Nb4 Cells

Human C/EBPε is a newly cloned CCAAT/enhancer-binding transcription factor. Initial studies indicated it may be an important regulator of human myelopoiesis. To elucidate the range of expression of C/EBPε, we used reverse transcription-polymerase chain reaction (RT-PCR) analysis and examined its expression in 28 hematopoietic and 14 nonhematopoietic cell lines, 16 fresh myeloid leukemia samples, and normal human hematopoietic stem cells and their mature progeny. Prominent expression of C/EBPε mRNA occurred in the late myeloblastic and promyelocytic cell lines (NB4, HL60, GFD8), the myelomonoblastic cell lines (U937 and THP-1), the early myeloblast cell lines (ML1, KCL22, MDS92), and the T-cell lymphoblastic leukemia cell lines CEM and HSB-2. For the acute promyelocytic leukemia cell line NB4, C/EBPε was the only C/EBP family member that was easily detected by RT-PCR. No C/EBPε mRNA was found in erythroid, megakaryocyte, basophil, B lymphoid, or nonhematopoietic cell lines. Most acute myeloid leukemia samples (11 of 12) from patients expressed C/EBPε. Northern blot and RT-PCR analyses showed that C/EBPε mRNA decreased when the HL60 and KG-1 myeloblast cell lines were induced to differentiate toward macrophages. Similarly, Western blot analysis showed that expression of C/EBPε protein was either unchanged or decreased slightly as the promyelocytic cell line NB4 differentiated down the macrophage-like pathway after treatment with a potent vitamin D3 analog (KH1060). In contrast, C/EBPε protein levels increased dramatically as NB4 cells were induced to differentiate down the granulocytic pathway after exposure to 9-cis retinoic acid. Furthermore, very early, normal hematopoietic stem cells (CD34+/CD38−), purified from humans had very weak expression of C/EBPε mRNA, but levels increased as these cells differentiated towards granulocytes. Likewise, purified granulocytes appeared to express higher levels of C/EBPε mRNA than purified macrophages. Addition of phosphothiolated antisense, but not sense oligonucleotides to C/EBPε, decreased clonal growth of HL-60 and NB4 cells by about 50% compared with control cultures. Taken together, our results indicate that expression of C/EBPε is restricted to hematopoietic tissues, especially myeloid cells as they differentiate towards granulocytes and inhibition of its expression in HL-60 and NB4 myeloblasts and promyelocytes decreased their proliferative capacity. Therefore, this transcriptional factor may play an important role in the process of normal myeloid development.

The transcription factor Erg is essential for definitive hematopoiesis and the function of adult hematopoietic stem cells

2008 ◽  
Vol 9 (7) ◽  
pp. 810-819 ◽  
Author(s):  
Stephen J Loughran ◽  
Elizabeth A Kruse ◽  
Douglas F Hacking ◽  
Carolyn A de Graaf ◽  
Craig D Hyland ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transcription Factor ◽  
Hematopoietic Stem Cells ◽  
Hematopoietic Stem ◽  
Definitive Hematopoiesis

Role of the Transcription Factor LYL-1 in the Adult and Fetal Hematopoietic Stem Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2775-2775
Author(s):  
Claude Capron ◽  
Catherine Lacout ◽  
Yann Lecluse ◽  
Isabelle Poullion ◽  
Fedor Svinarchouk ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transcription Factor ◽  
Hematopoietic Stem Cells ◽  
Absolute Number ◽  
Binding Motif ◽  
Hematopoietic Stem ◽  
Cell Counts ◽  
Significant Difference ◽  
The Absolute

Abstract The hematopoietic stem cells (HSC) have the ability to self-renew and to give rise to all blood lineages. These processes occur via a hierarchy of progenitors with progressively more limited differentiation and self-renewal potential and are orchestrated by specialized protein such as transcription factors. LYL-1 protein contains a basic helix-loop-helix DNA binding motif also found in several proteins involved in the control of cellular proliferation and differentiation such as SCL/TAL-1. As LYL-1 shares an 80% homology at the protein level with SCL/TAL-1, we wanted to determine the function of LYL-1 in hematopoiesis and particularly on HSC. For this study, we used knock in lyl-1−/− mice in which exon 4 was replaced by LacZ/Neo cassette. Lyl−/− mice are viable and have normal blood cell counts as well as a normal marrow cellularity. In addition, using a hematopoietic colony forming cells (CFCs) assay, no significant difference was seen in the myeloid CFCs of either lyl-1−/− or lyl-1+/+ BM and FL cells except a 2-fold increase in the absolute number of BFU-E in lyl-1−/− FL as compared to lyl-1+/+ FL. We analyzed more primitive progenitors in details because using Fluorecein Di-beta Galactopyranoside (FDG)-staining assay, we showed that lyl-1 is mainly expressed in primitive Lin− Sca-1+ c-Kit+ cells (LSK) cells from either BM or FL (91 ± 7% and 78 ± 5% of FDG positive cells in lyl-1−/− BM and FL LSK cells, respectively). In addition, analysis of lyl-1−/− and lyl-1+/+ cells revealed a 1.8-fold and 2-fold decrease in the percentage of primitive LSK in BM and FL, respectively, as compared to wild type cells. Furthermore, using the Hoechst 33342 efflux assay, we noticed a significant decrease in the absolute number of more primitive LSK-SP (side population) cells in lyl-1−/− BM as compared to lyl-1+/+ BM cells (52800 ± 5412 cells/femur versus 91080 ± 8475 cells/femur, respectively) suggesting an important role of LYL-1 in the HSC function. In order to confirm this hypothesis, in vivo assays were performed. We observed a 1.5-fold decrease in the lyl-1−/− BM and FL day 12 CFU-S content as compared to lyl-1+/+ cells. Adoptive transfer experiments were subsequently performed using lethally irradiated Ly5.1 mice. Data showed that lyl-1−/− cells from either BM or FL displayed a hematopoietic reconstitution defect in competitive repopulation assays. Indeed, Ly5.1 recipients were injected with a mixture of 5x106 (5:1), 106 (1:1) or 0.5x106 (0.5:1) lyl-1−/− or lyl-1+/+ Ly5.2 expressing cells and 106 competitive BM Ly5.1 expressing cells. All hosts engrafted with lyl-1−/− BM cells shown a significant reduced levels of chimerism (% of circulating Ly5.2+ cells) as compared to hosts engrafted with lyl-1+/+ BM donors (4.3 ± 2.8% (5:1); 7.5 ± 5.5% (1:1); 0.6 ± 0.3% (0.5:1) in lyl-1−/− BM cells versus 66 ± 8% (5:1); 52 ± 9% (1:1); 53 ± 10% (0.5:1) in lyl-1+/+ BM cells) and similar difference was observed with FL donors (45 ± 2% (5:1); 25 ± 5% (1:1); 11 ± 5% (0.5:1) in lyl-1−/− FL cells versus 83 ± 1% (5:1); 70 ± 3% (1:1); 53 ± 6% (0.5:1) in lyl-1+/+ FL cells). This altered defect in HSC was also confirmed using LTC-IC in vitro experiments. Altogether, our results demonstrate an important role of the transcription factor LYL-1 on the maintenance of HSC properties.

Induction of Adipocyte Differentiation and Reduction of Hematopoesis-Supporting Activity of Mouse Stromal Cells by Suppression of Transcription Factor GATA-2.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1392-1392
Author(s):  
Yoko Okitsu ◽  
Hideo Harigae ◽  
Masanori Seki ◽  
Toru Fujiwara ◽  
Shinichiro Takahashi ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Transcription Factor ◽  
Hematopoietic Stem Cells ◽  
Stromal Cells ◽  
Colony Formation ◽  
Adipocyte Differentiation ◽  
Fetal Liver ◽  
Expression Level ◽  
Hematopoietic Stem

Abstract (Introduction) Aplastic anemia (AA) is characterized by peripheral pancytopenia and fatty bone marrow. An immunological attack to hematopoietic stem cells has been thought to be responsible for the development of the disease. Previously, we reported the expression of transcription factor GATA-2 is significantly decreased in CD34 positive cells in AA. Together with the phenotypes of hematopoietic stem cells in GATA-2 hetero-knockout mice, GATA-2 down-regulation may play a role in the reduction of a stem cell pool observed in AA. On the other hand, GATA-2 has been shown to be essential for the maintenance of immaturity of preadipocytes. If a pathological immune response in AA decreases the level of GATA-2 expression in not only hematopoietic stem cells but also stromal preadipocytes, it may accelerate the maturation of preadipocytes, leading to the formation of fatty bone marrow. To explore this possibility, the phenotypic change of stromal preadipocytes by suppression of GATA-2 was examined in this study. (Method) The GATA-2 expression level was suppressed by using siRNA for GATA-2 in mouse stromal preadipocyte cell lines, TBR9 and TBR343. After the treatment with siRNA, the adipocyte differentiation was induced by the incubation with insulin and dexamethasone for 7days. Then, the maturation level was examined by oil drops formation judged by oil red staining, and by the expression level of adipcin and PPAR-γ mRNA. Supporting activity of hematopoietic colony formation was also evaluated by using mouse fetal liver cells after siRNA treatment. (Results) By using designed siRNA, the GATA-2 expression was suppressed to 30% of control, whereas the expression level of GATA-3, which is co-expressed in preadipocytes, was unchanged. When GATA-2 was suppressed by siRNA, the oil drop formation and adipocyte-specific gene expression was significantly accelerated in both of stromal cells. Furthermore, the number of fetal liver hematopoetic colonies was significantly decreased by suppression of GATA-2, suggesting that GATA-2 down-regulation in stromal preadipocytes results in not only the acceleration of the maturation but also the reduced supporting activity of hematopoietic colony formation (Conclusion) These results suggest that suppression of GATA-2 in hematopoietic tissues induces the characteristic features of AA, i.e., decreased the number of hematopoietic stem cells and increased number of mature adipocytes.

scholarly journals A Novel, Myeloid Transcription Factor, C/EBPε, Is Upregulated During Granulocytic, But Not Monocytic, Differentiation

Blood ◽  
1997 ◽  
Vol 90 (7) ◽  
pp. 2591-2600 ◽  
Author(s):  
Roberta Morosetti ◽  
Dorothy J. Park ◽  
Alexey M. Chumakov ◽  
Isabelle Grillier ◽  
Masaaki Shiohara ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transcription Factor ◽  
Hematopoietic Stem Cells ◽  
Cell Line ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Leukemia Cell ◽  
Rt Pcr ◽  
Hematopoietic Stem ◽  
Nb4 Cells

Abstract Human C/EBPε is a newly cloned CCAAT/enhancer-binding transcription factor. Initial studies indicated it may be an important regulator of human myelopoiesis. To elucidate the range of expression of C/EBPε, we used reverse transcription-polymerase chain reaction (RT-PCR) analysis and examined its expression in 28 hematopoietic and 14 nonhematopoietic cell lines, 16 fresh myeloid leukemia samples, and normal human hematopoietic stem cells and their mature progeny. Prominent expression of C/EBPε mRNA occurred in the late myeloblastic and promyelocytic cell lines (NB4, HL60, GFD8), the myelomonoblastic cell lines (U937 and THP-1), the early myeloblast cell lines (ML1, KCL22, MDS92), and the T-cell lymphoblastic leukemia cell lines CEM and HSB-2. For the acute promyelocytic leukemia cell line NB4, C/EBPε was the only C/EBP family member that was easily detected by RT-PCR. No C/EBPε mRNA was found in erythroid, megakaryocyte, basophil, B lymphoid, or nonhematopoietic cell lines. Most acute myeloid leukemia samples (11 of 12) from patients expressed C/EBPε. Northern blot and RT-PCR analyses showed that C/EBPε mRNA decreased when the HL60 and KG-1 myeloblast cell lines were induced to differentiate toward macrophages. Similarly, Western blot analysis showed that expression of C/EBPε protein was either unchanged or decreased slightly as the promyelocytic cell line NB4 differentiated down the macrophage-like pathway after treatment with a potent vitamin D3 analog (KH1060). In contrast, C/EBPε protein levels increased dramatically as NB4 cells were induced to differentiate down the granulocytic pathway after exposure to 9-cis retinoic acid. Furthermore, very early, normal hematopoietic stem cells (CD34+/CD38−), purified from humans had very weak expression of C/EBPε mRNA, but levels increased as these cells differentiated towards granulocytes. Likewise, purified granulocytes appeared to express higher levels of C/EBPε mRNA than purified macrophages. Addition of phosphothiolated antisense, but not sense oligonucleotides to C/EBPε, decreased clonal growth of HL-60 and NB4 cells by about 50% compared with control cultures. Taken together, our results indicate that expression of C/EBPε is restricted to hematopoietic tissues, especially myeloid cells as they differentiate towards granulocytes and inhibition of its expression in HL-60 and NB4 myeloblasts and promyelocytes decreased their proliferative capacity. Therefore, this transcriptional factor may play an important role in the process of normal myeloid development.

scholarly journals GATA-2 Plays Two Functionally Distinct Roles during the Ontogeny of Hematopoietic Stem Cells

2004 ◽  
Vol 200 (7) ◽  
pp. 871-882 ◽  
Author(s):  
Kam-Wing Ling ◽  
Katrin Ottersbach ◽  
Jan Piet van Hamburg ◽  
Aneta Oziemlak ◽  
Fong-Ying Tsai ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Transcription Factor ◽  
Hematopoietic Stem Cells ◽  
Gene Dosage ◽  
Fetal Liver ◽  
Mouse Development ◽  
Hematopoietic Stem ◽  
Adult Bone Marrow ◽  
Adult Bone

GATA-2 is an essential transcription factor in the hematopoietic system that is expressed in hematopoietic stem cells (HSCs) and progenitors. Complete deficiency of GATA-2 in the mouse leads to severe anemia and embryonic lethality. The role of GATA-2 and dosage effects of this transcription factor in HSC development within the embryo and adult are largely unexplored. Here we examined the effects of GATA-2 gene dosage on the generation and expansion of HSCs in several hematopoietic sites throughout mouse development. We show that a haploid dose of GATA-2 severely reduces production and expansion of HSCs specifically in the aorta-gonad-mesonephros region (which autonomously generates the first HSCs), whereas quantitative reduction of HSCs is minimal or unchanged in yolk sac, fetal liver, and adult bone marrow. However, HSCs in all these ontogenically distinct anatomical sites are qualitatively defective in serial or competitive transplantation assays. Also, cytotoxic drug-induced regeneration studies show a clear GATA-2 dose–related proliferation defect in adult bone marrow. Thus, GATA-2 plays at least two functionally distinct roles during ontogeny of HSCs: the production and expansion of HSCs in the aorta-gonad-mesonephros and the proliferation of HSCs in the adult bone marrow.

ETO2 Controls Hematopoietic Stem Cell Expansion.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 396-396
Author(s):  
Stephane Barakat ◽  
Julie Lambert ◽  
Guy Sauvageau ◽  
Trang Hoang
Keyword(s):  
Stem Cells ◽  
Transcription Factor ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Short Term ◽  
Self Renewal ◽  
Hematopoietic Stem

Abstract Abstract 396 Hematopoietic stem cells that provide short term reconstitution (ST-HSCs) as well as hematopoietic progenitors expand from a small population of long term hematopoietic stem cells (LT-HSCs) that are mostly dormant cells. The mechanisms underlying this expansion remain to be clarified. SCL (stem cell leukemia), is a bHLH transcription factor that controls HSC quiescence and long term competence. Using a proteomics approach to identify components of the SCL complex in erythroid cells, we and others recently showed that the ETO2 co-repressor limits the activity of the SCL complex via direct interaction with the E2A transcription factor. ETO2/CBF2T3 is highly homologous to ETO/CBFA2T1 and both are translocation partners for AML1. We took several approaches to identify ETO2 function in HSCs. We initially found by Q-PCR that ETO2 is highly expressed in populations of cells enriched in short-term HSC (CD34+Flt3-Kit+Sca+Lin-) and lympho-myeloid progenitors (CD34+Flt3+Kit+Sca+Lin-) and at lower levels in LT-HSCs (CD34-Kit+Sca+Lin- or CD150+CD48-Kit+Sca+Lin-). Next, the role of ETO2 was studied by overexpression or downregulation combined with transplantation in mice. Ectopic ETO2 expression induces a 100 fold expansion of LT-HSCs in vivo in transplanted mice associated with differentiation blockade in all lineages, suggesting that ETO2 overexpression overcomes the mechanisms that limit HSC expansion in vivo. We are currently testing the role of the NHR1 domain of ETO2 in this expansion. Conversely, shRNAs directed against ETO2 knock down ET02 levels in Kit+Sca+Lin- cells, causing a ten-fold decrease in this population after transplantation, associated with reduced short-term reconstitution in mice. Finally, proliferation assays using Hoechst and CFSE indicate that ETO2 downregulation affects cell division (CFSE) and leads to an accumulation of Kit+Sca+Lin-cells in G0/G1 state (Hoescht). In conclusion, we show that ETO2 is highly expressed in ST-HSCs and lymphoid progenitors, and controls their expansion by regulating cell cycle entry at the G1-S checkpoint. In addition, ETO2 overexpression converts the self-renewal of maintenance into self-renewal of expansion in LT-HSCs. Disclosures: No relevant conflicts of interest to declare.

Molecular and Functional Characterization of Early Lineage Commitment of Human Hematopoietic Stem Cells

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 907-907
Author(s):  
Elisa Laurenti ◽  
Sergei Doulatov ◽  
Sasan Zandi ◽  
Jing Chen ◽  
Craig April ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Transcription Factor ◽  
Hematopoietic Stem Cells ◽  
B Cell ◽  
Cell Types ◽  
Cell Maturation ◽  
Hematopoietic Stem ◽  
B Cell Maturation ◽  
Early Human

Abstract Abstract 907 The hematopoietic system is a highly regulated cellular hierarchy, responsible for the day-to-day production of mature blood cells which can be divided in two major lineages, myeloid and lymphoid. Hematopoietic stem cells (HSCs) have the unique ability to give rise to all hematopoietic cell types, by first generating lineage-commited progenitors which in turn will produce terminally differentiated cells. HSCs are characterized by their extensive self-renewal and differentiation capacities. While in mice the mechanisms underlying early HSC differentiation and lineage determination are well understood at the molecular level, very few transcription factors regulating lineage decisions have been identified in human hematopoiesis. Our group has recently established a novel cell sorting strategy for human HSCs and early lineage committed progenitors (Doulatov et al., Nature Immunology, 2010; Notta et al., Science, 2011) which uncovered the existence of a novel human multilymphoid progenitor (MLP). MLPs give rise to all lymphoid cell types, as well as dendritic cells and monocytic cells. Here we report a comprehensive analysis of gene expression at each developmental stage of the early human hematopoietic hierarchy, ranging from the long-term repopulating stem cells to lineage-restricted progenitors through multipotent progenitors such as MLP, CMP (common myeloid progenitor), GMP (granulocyte-monocyte progenitor) and MEP (megakaryocyte-erythroid progenitor). We show that hematopoietic specification is defined by a small number of global gene expression clusters that correspond to major biological lineages and that lineage programs in committed progenitors are paired with HSC-shared priming programs. HSCs display most extensive priming along the lympho-myeloid branch (MLP). In contrast early progenitors of the megakaryocytic/erythrocytic lineage form a distinct cluster, highly enriched for cell cycle genes. To identify regulators of each major developmental transition, we computationally extracted population-specific gene-sets (“signatures”). We then integrated transcription factor expression data and enrichment of transcription factors binding sites in the promoters of each “signature” to obtain a map of transcriptional regulators in the context of the developmental hierarchy. Based on this model, we selected more than 15 candidate genes for functional validation. We chose genes predicted to act either on lymphoid (MLP), myeloid (MLP, CMP) or erythroid (MEP) commitment. Among these, we investigated the function of BCL11a, a C2H2 zinc finger transcriptional repressor, which expression is primed in HSCs then peaks in the newly discovered MLP population, indicating a putative role in lymphocyte specification. Consistent with this hypothesis, BCL11a has been implicated in the development of B cell progenitors in mouse. When BCL11a was knocked down in cord blood derived hematopoietic stem cells and early progenitors, we observed reduced formation of cells committed to the B cell fate both in vitro and in an in vivo xenograft assay. BCL11a knock-down resulted in a partial block of B cell maturation at the proB to preB cell transition, that was accompanied by a decrease in the key B cell maturation transcription factor, Pax5. These preliminary results suggest that BCL11a directs B cell specification in human and that our genome-wide strategy not only provides a valuable resource for the hematology community but also allows identification of key regulators of early human lineage commitment. Disclosures: No relevant conflicts of interest to declare.

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