scholarly journals Upregulation of Interleukin 6 and Granulocyte Colony-Stimulating Factor Receptors by Transcription Factor CCAAT Enhancer Binding Protein α (C/EBPα) Is Critical for Granulopoiesis

1998 ◽  
Vol 188 (6) ◽  
pp. 1173-1184 ◽  
Author(s):  
Pu Zhang ◽  
Atsushi Iwama ◽  
Milton W. Datta ◽  
Gretchen J. Darlington ◽  
Daniel C. Link ◽  
...  
Keyword(s):  
Interleukin 6 ◽  
Target Genes ◽  
Binding Protein ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Stimulating Factor ◽  
Deficient Mice

Cytokines stimulate granulopoiesis through signaling via receptors whose expression is controlled by lineage-specific transcription factors. Previously, we demonstrated that granulocyte colony-stimulating factor (G-CSF) receptor mRNA was undetectable and granulocyte maturation blocked in CCAAT enhancer binding protein α (C/EBPα)-deficient mice. This phenotype is distinct from that of G-CSF receptor−/− mice, suggesting that other genes are likely to be adversely affected by loss of C/EBPα. Here we demonstrate loss of interleukin 6 (IL-6) receptor and IL-6–responsive colony-forming units (CFU-IL6) in C/EBPα−/− mice. The observed failure of granulopoiesis could be rescued by the addition of soluble IL-6 receptor and IL-6 or by retroviral transduction of G-CSF receptors, demonstrating that loss of both of these receptors contributes to the absolute block in granulocyte maturation observed in C/EBPα-deficient hematopoietic cells. The results of these and other studies suggest that additional C/EBPα target genes, possibly other cytokine receptors, are also important for the block in granulocyte differentiation observed in vivo in C/EBPα-deficient mice.

scholarly journals Interleukin-6 and the Granulocyte Colony-Stimulating Factor Receptor Are Major Independent Regulators of Granulopoiesis In Vivo But Are Not Required for Lineage Commitment or Terminal Differentiation

Blood ◽  
1997 ◽  
Vol 90 (7) ◽  
pp. 2583-2590 ◽  
Author(s):  
Fulu Liu ◽  
Jennifer Poursine-Laurent ◽  
Huai Yang Wu ◽  
Daniel C. Link
Keyword(s):  
Interleukin 6 ◽  
Terminal Differentiation ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Normal Numbers ◽  
Stimulating Factor ◽  
Deficient Mice ◽  
Additional Loss

Multiple hematopoietic cytokines can stimulate granulopoiesis; however, their relative importance in vivo and mechanisms of action remain unclear. We recently reported that granulocyte colony-stimulating factor receptor (G-CSFR)-deficient mice have a severe quantitative defect in granulopoiesis despite which phenotypically normal neutrophils were still detected. These results confirmed a role for the G-CSFR as a major regulator of granulopoiesis in vivo, but also indicated that G-CSFR independent mechanisms of granulopoiesis must exist. To explore the role of interleukin-6 (IL-6) in granulopoiesis, we generated IL-6 × G-CSFR doubly deficient mice. The additional loss of IL-6 significantly worsened the neutropenia present in young adult G-CSFR–deficient mice; moreover, exogenous IL-6 stimulated granulopoiesis in vivo in the absence of G-CSFR signals. Near normal numbers of myeloid progenitors were detected in the bone marrow of IL-6 × G-CSFR–deficient mice and their ability to terminally differentiate into mature neutrophils was observed. These results indicate that IL-6 is an independent regulator of granulopoiesis in vivo and show that neither G-CSFR or IL-6 signals are required for the commitment of multipotential progenitors to the myeloid lineage or for their terminal differentiation.

Granulocyte colony-stimulating factor regulates myeloid differentiation through CCAAT/enhancer-binding protein ε

Blood ◽  
2001 ◽  
Vol 98 (4) ◽  
pp. 897-905 ◽  
Author(s):  
Hideaki Nakajima ◽  
James N. Ihle
Keyword(s):  
Molecular Mechanisms ◽  
Binding Protein ◽  
Hematopoietic Cells ◽  
Myeloid Differentiation ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Granulocytic Differentiation ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Stimulating Factor

Granulocyte colony-stimulating factor (G-CSF) is a major cytokine that regulates proliferation and differentiation of myeloid cells, although the underlying mechanisms by which G-CSF controls myeloid differentiation are largely unknown. Differentiation of hematopoietic cells is regulated by lineage-specific transcription factors, and gene-targeting studies previously revealed the critical roles of CCAAT/enhancer-binding protein (C/EBP) α and C/EBPε, respectively, in the early and mid-late stages of granulocyte differentiation. The expression of C/EBPε in 32Dcl3 cells and FDCP1 cells expressing mutant G-CSF receptors was examined and it was found that G-CSF up-regulates C/EBPε. The signal for this expression required the region containing the first tyrosine residue of G-CSF receptor. Dominant-negative signal transducers and activators of transcription 3 blocked G-CSF–induced granulocytic differentiation in 32D cells but did not block induction of C/EBPε, indicating that these proteins work in different pathways. It was also found that overexpression of C/EBPε greatly facilitated granulocytic differentiation by G-CSF and, surprisingly, that expression of C/EBPε alone was sufficient to make cells differentiate into morphologically and functionally mature granulocytes. Overexpression of c-myc inhibits differentiation of hematopoietic cells, but the molecular mechanisms of this inhibition are not fully understood. In 32Dcl3 cells overexpressing c-myc that do not differentiate by means of G-CSF, induction of C/EBPε is completely abrogated. Ectopic expression of C/EBPε in these cells induced features of differentiation, including changes in nuclear morphologic characteristics and the appearance of granules. These data show that C/EBPε constitutes a rate-limiting step in G-CSF–regulated granulocyte differentiation and that c-myc antagonizes G-CSF–induced myeloid differentiation, at least partly by suppressing induction of C/EBPε.

scholarly journals Interleukin-6 and the Granulocyte Colony-Stimulating Factor Receptor Are Major Independent Regulators of Granulopoiesis In Vivo But Are Not Required for Lineage Commitment or Terminal Differentiation

Blood ◽  
1997 ◽  
Vol 90 (7) ◽  
pp. 2583-2590 ◽  
Author(s):  
Fulu Liu ◽  
Jennifer Poursine-Laurent ◽  
Huai Yang Wu ◽  
Daniel C. Link
Keyword(s):  
Interleukin 6 ◽  
Terminal Differentiation ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Normal Numbers ◽  
Stimulating Factor ◽  
Deficient Mice ◽  
Additional Loss

Abstract Multiple hematopoietic cytokines can stimulate granulopoiesis; however, their relative importance in vivo and mechanisms of action remain unclear. We recently reported that granulocyte colony-stimulating factor receptor (G-CSFR)-deficient mice have a severe quantitative defect in granulopoiesis despite which phenotypically normal neutrophils were still detected. These results confirmed a role for the G-CSFR as a major regulator of granulopoiesis in vivo, but also indicated that G-CSFR independent mechanisms of granulopoiesis must exist. To explore the role of interleukin-6 (IL-6) in granulopoiesis, we generated IL-6 × G-CSFR doubly deficient mice. The additional loss of IL-6 significantly worsened the neutropenia present in young adult G-CSFR–deficient mice; moreover, exogenous IL-6 stimulated granulopoiesis in vivo in the absence of G-CSFR signals. Near normal numbers of myeloid progenitors were detected in the bone marrow of IL-6 × G-CSFR–deficient mice and their ability to terminally differentiate into mature neutrophils was observed. These results indicate that IL-6 is an independent regulator of granulopoiesis in vivo and show that neither G-CSFR or IL-6 signals are required for the commitment of multipotential progenitors to the myeloid lineage or for their terminal differentiation.

scholarly journals Mice lacking granulocyte colony-stimulating factor have chronic neutropenia, granulocyte and macrophage progenitor cell deficiency, and impaired neutrophil mobilization

Blood ◽  
1994 ◽  
Vol 84 (6) ◽  
pp. 1737-1746 ◽  
Author(s):  
GJ Lieschke ◽  
D Grail ◽  
G Hodgson ◽  
D Metcalf ◽  
E Stanley ◽  
...  
Keyword(s):  
Gene Dosage ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Targeted Disruption ◽  
Gene Dosage Effect ◽  
Peripheral Blood Neutrophil ◽  
Stimulating Factor ◽  
Deficient Mice ◽  
Chronic Neutropenia

Mice lacking granulocyte colony-stimulating factor (G-CSF) were generated by targeted disruption of the G-CSF gene in embryonal stem cells. G-CSF-deficient mice (genotype G-CSF-/-) are viable, fertile, and superficially healthy, but have a chronic neutropenia. Peripheral blood neutrophil levels were 20% to 30% of wild-type mice (genotype G- CSF+/+) and mice heterozygous for the null mutation had intermediate neutrophil levels, suggesting a gene-dosage effect. In the marrow of G- CSF-/- mice, granulopoietic precursor cells were reduced by 50% and there were reduced levels of granulocyte, macrophage, and blast progenitor cells. Despite G-CSF deficiency, mature neutrophils were still present in the blood and marrow, indicating that other factors can support neutrophil production in vivo. G-CSF-/- mice had reduced numbers of neutrophils available for rapid mobilization into the circulation by a single dose of G-CSF. G-CSF administration reversed the granulopoietic defect of G-CSF-/- mice. One day of G-CSF administration to G-CSF-/- mice elevated circulating neutrophil levels to normal, and after 4 days of G-CSF administration, G-CSF+/+ and G-CSF- /- marrows were morphologically indistinguishable. G-CSF-/- mice had a markedly impaired ability to control infection with Listeria monocytogenes, with diminished neutrophil and delayed monocyte increases in the blood and reduced infection-driven granulopoiesis. Collectively, these observations indicate that G-CSF is indispensible for maintaining the normal quantitative balance of neutrophil production during “steady-state” granulopoiesis in vivo and also implicate G-CSF in “emergency” granulopoiesis during infections.

scholarly journals CCAAT enhancer-binding protein (C/EBP) and AML1 (CBF alpha2) synergistically activate the macrophage colony-stimulating factor receptor promoter.

1996 ◽  
Vol 16 (3) ◽  
pp. 1231-1240 ◽  
Author(s):  
D E Zhang ◽  
C J Hetherington ◽  
S Meyers ◽  
K L Rhoades ◽  
C J Larson ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Protein C ◽  
Binding Protein ◽  
Colony Stimulating Factor ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Macrophage Colony Stimulating Factor ◽  
Macrophage Colony ◽  
Stimulating Factor

Transcription factors play a key role in the development and differentiation of specific lineages from multipotential progenitors. Identification of these regulators and determining the mechanism of how they activate their target genes are important for understanding normal development of monocytes and macrophages and the pathogenesis of a common form of adult acute leukemia, in which the differentiation of monocytic cells is blocked. Our previous work has shown that the monocyte-specific expression of the macrophage colony-stimulating factor (M-CSF) receptor is regulated by three transcription factors interacting with critical regions of the M-CSF receptor promoter, including PU.1 and AML1.PU.1 is essential for myeloid cell development, while the AML1 gene is involved in several common leukemia-related chromosome translocations, although its role in hematopoiesis has not been fully identified. Along with AML1, a third factor, Mono A, interacts with a small region of the promoter which can function as a monocyte-specific enhancer when multimerized and linked to a heterologous basal promoter. Here, we demonstrate by electrophoretic mobility shift assays with monocytic nuclear extracts, COS-7 cell-transfected factors, and specific antibodies that the monocyte-enriched factor Mono A is CCAAT enhancer-binding protein (C/EBP). C/EBP has been shown previously to be an important transcription factor involved in hepatocyte and adipocyte differentiation; in hematopoietic cells, C/EBP is specifically expressed in myeloid cells. In vitro binding analysis reveals a physical interaction between C/EBP and AML1. Further transfection studies show that C/EBP and AML1 in concert with the AML1 heterodimer partner CBF beta synergistically activate M-CSF receptor by more then 60 fold. These results demonstrate that C/EBP and AML1 are important factors for regulating a critical hematopoietic growth factor receptor, the M-CSF receptor, suggesting a mechanism of how the AML1 fusion protein could contribute to acute myeloid leukemia. Furthermore, they demonstrate physical and functional interactions between AML1 and C/EBP transcription factor family members.

AML1-MTG8 leukemic protein induces the expression of granulocyte colony-stimulating factor (G-CSF) receptor through the up-regulation of CCAAT/enhancer binding protein epsilon

Blood ◽  
2000 ◽  
Vol 96 (1) ◽  
pp. 288-296 ◽  
Author(s):  
Kimiko Shimizu ◽  
Issay Kitabayashi ◽  
Nanao Kamada ◽  
Tatsuo Abe ◽  
Nobuo Maseki ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Binding Protein ◽  
Ectopic Expression ◽  
Precursor Cells ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
G Cells ◽  
Enhancer Binding Protein ◽  
Dependent Cell ◽  
Stimulating Factor

The t(8;21) translocation is one of the most frequent chromosomal abnormalities associated with acute myeloid leukemia (AML). In this translocation, the AML1 (CBFA2/PEBP2aB) gene is disrupted and fused to the MTG8 (ETO) gene. The ectopic expression of the resulting AML1-MTG8 fusion gene product in L-G and 32Dcl3 murine myeloid precursor cells stimulates cell proliferation without inducing morphologic terminal differentiation into mature granulocytes in response to granulocyte-colony stimulating factor (G-CSF). This study found that the ectopic expression of AML1-MTG8 elevates the expression of the G-CSF receptor (G-CSFR). Analysis of the promoter region of the G-CSFR gene revealed that up-regulation of G-CSFR expression by AML1-MTG8 does not depend on the AML1-binding sequence, but on the C/EBP (CCAAT/enhancer binding protein) binding site. The results suggest that the overproduction of G-CSFR is at least partly mediated by C/EBPɛ, whose expression is activated by AML1-MTG8. The ectopic expression of G-CSFR in L-G cells induced cell proliferation in response to G-CSF, but did not inhibit cell differentiation into mature neutrophils. Overexpression of C/EBPɛ in L-G cells also stimulated G-CSF–dependent cell proliferation. High expression levels of G-CSFR were also found in the leukemic cells of AML patients with t(8;21). Therefore, G-CSF–dependent cell proliferation of myeloid precursor cells may be implicated in leukemogenesis.

scholarly journals Mice lacking granulocyte colony-stimulating factor have chronic neutropenia, granulocyte and macrophage progenitor cell deficiency, and impaired neutrophil mobilization

Blood ◽  
1994 ◽  
Vol 84 (6) ◽  
pp. 1737-1746 ◽  
Author(s):  
GJ Lieschke ◽  
D Grail ◽  
G Hodgson ◽  
D Metcalf ◽  
E Stanley ◽  
...  
Keyword(s):  
Gene Dosage ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Targeted Disruption ◽  
Gene Dosage Effect ◽  
Peripheral Blood Neutrophil ◽  
Stimulating Factor ◽  
Deficient Mice ◽  
Chronic Neutropenia

Abstract Mice lacking granulocyte colony-stimulating factor (G-CSF) were generated by targeted disruption of the G-CSF gene in embryonal stem cells. G-CSF-deficient mice (genotype G-CSF-/-) are viable, fertile, and superficially healthy, but have a chronic neutropenia. Peripheral blood neutrophil levels were 20% to 30% of wild-type mice (genotype G- CSF+/+) and mice heterozygous for the null mutation had intermediate neutrophil levels, suggesting a gene-dosage effect. In the marrow of G- CSF-/- mice, granulopoietic precursor cells were reduced by 50% and there were reduced levels of granulocyte, macrophage, and blast progenitor cells. Despite G-CSF deficiency, mature neutrophils were still present in the blood and marrow, indicating that other factors can support neutrophil production in vivo. G-CSF-/- mice had reduced numbers of neutrophils available for rapid mobilization into the circulation by a single dose of G-CSF. G-CSF administration reversed the granulopoietic defect of G-CSF-/- mice. One day of G-CSF administration to G-CSF-/- mice elevated circulating neutrophil levels to normal, and after 4 days of G-CSF administration, G-CSF+/+ and G-CSF- /- marrows were morphologically indistinguishable. G-CSF-/- mice had a markedly impaired ability to control infection with Listeria monocytogenes, with diminished neutrophil and delayed monocyte increases in the blood and reduced infection-driven granulopoiesis. Collectively, these observations indicate that G-CSF is indispensible for maintaining the normal quantitative balance of neutrophil production during “steady-state” granulopoiesis in vivo and also implicate G-CSF in “emergency” granulopoiesis during infections.

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