Project description:Severe congenital neutropenia (SCN) is a rare disorder characterized by a maturation arrest of myeloid progenitor cells in the bone marrow and severe reduction in the amount of circulating neutrophils. Loss-of-function mutations in the CSF3R (the gene encoding the granulocyte colony-stimulating factor (G-CSF) receptor) have been reported in a handful of cases. We describe two novel pedigrees with moderate neutropenia. G-CSFR immunostaining was greatly reduced on patient neutrophils. G-CSF did not prolong neutrophil survival or enhanced reactive oxygen species generation, and STAT-3 phosphorylation was absent, while neutrophils did respond to granulocyte-macrophage colony-stimulating factor (GM-CSF). Despite a lack of G-CSF signaling, morphology and cellular proteomics were normal. We suggest the major role of G-CSF is not in myeloid differentiation, but in generation of sufficient number of committed progenitor cells for neutrophil release and their survival during inflammation, which corresponds with G-CSFR expression in myeloid cell fractions from bone marrow of healthy individuals.
Project description:Highly purified Hematopoietic stem cells (HSC) from mouse bone marrow (BM) were compared to HSC after two days of cytoxan/GCSF treatment (Cyclophosphamide/granulocyte colony-stimulating factor) (Day2Mob) and leukemic HSC from mice lacking JunB. See Forsberg et. al. 2010 for details. CML - chronic myelogenous leukemia. Biological Replicate
Project description:Adult hematopoietic stem cells (HSCs) reside primarily in bone marrow. However, hematopoietic stresses such as myelofibrosis, anemia, pregnancy, infection or myeloablation can mobilize HSCs to the spleen and induce extramedullary hematopoiesis (EMH). While the bone marrow HSC niche has been studied intensively, the EMH niche has received little attention. Here, we systematically assessed the physiological sources of the key niche factors, SCF and CXCL12, in the mouse spleen after EMH induction by cyclophosphamide plus granulocyte colony-stimulating factor, blood loss, or pregnancy. In each case, Scf was expressed by endothelial cells and Tcf21+ stromal cells, primarily around sinusoids in red pulp, while Cxcl12 was expressed by a subset of Tcf21+ stromal cells. EMH induction markedly expanded the Scf-expressing endothelial cells and stromal cells by inducing proliferation. Most splenic HSCs were adjacent to Tcf21+ stromal cells in red pulp. Conditional deletion of Scf from spleen endothelial cells or Scf or Cxcl12 from Tcf21+ stromal cells severely reduced spleen EMH and reduced blood cell counts without affecting bone marrow hematopoiesis. Endothelial cells and Tcf21+ stromal cells thus create the splenic EMH niche, which is necessary for the physiological response to diverse hematopoietic stresses. Unfractionated spleen cells (2 replicates) and FACS-sorted VE-cadherein negative Scf-GFP positive cells (3 replicates)
Project description:Highly purified Hematopoietic stem cells (HSC) from mouse bone marrow (BM) were compared to HSC after two days of cytoxan/GCSF treatment (Cyclophosphamide/granulocyte colony-stimulating factor) (Day2Mob) and leukemic HSC from mice lacking JunB. See Forsberg et. al. 2010 for details. CML - chronic myelogenous leukemia.
Project description:Neutrophil homeostasis is maintained, in part, by the regulated release of neutrophils from the bone marrow. Constitutive expression of the chemokine CXCL12 by bone marrow stromal cells provides a key retention signal for neutrophils in the bone marrow through activation of its receptor CXCR4. Herein, we show that the ELR chemokines CXCL1 and CXCL2 are constitutively expressed by bone marrow endothelial cells and osteoblasts, and CXCL2 expression is induced in endothelial cells during granulocyte colony-stimulating factor (G-CSF)-induced neutrophil mobilization. Neutrophils lacking CXCR2, the receptor for CXCL1 and CXCL2, are preferentially retained in the bone marrow, reproducing a myelokathexis phenotype. Transient disruption of CXCR4 failed to mobilize CXCR2 neutrophils. However, doubly deficient neutrophils (CXCR2-/- CXCR4-/-) displayed constitutive mobilization, showing that CXCR4 plays a dominant role. Collectively, these data suggest that CXCR2 signaling is a second chemokine axis that interacts antagonistically with CXCR4 to regulate neutrophil release from the bone marrow. We used gene expression microarrays to determine the changes in osteoblasts and bone marrow endothelial cells after G-CSF treatment. 3 untreated and G-CSF-treated osteoblast samples and 4 untreated and G-CSF-treated endothelial samples.
Project description:Adult hematopoietic stem cells (HSCs) reside primarily in bone marrow. However, hematopoietic stresses such as myelofibrosis, anemia, pregnancy, infection or myeloablation can mobilize HSCs to the spleen and induce extramedullary hematopoiesis (EMH). While the bone marrow HSC niche has been studied intensively, the EMH niche has received little attention. Here, we systematically assessed the physiological sources of the key niche factors, SCF and CXCL12, in the mouse spleen after EMH induction by cyclophosphamide plus granulocyte colony-stimulating factor, blood loss, or pregnancy. In each case, Scf was expressed by endothelial cells and Tcf21+ stromal cells, primarily around sinusoids in red pulp, while Cxcl12 was expressed by a subset of Tcf21+ stromal cells. EMH induction markedly expanded the Scf-expressing endothelial cells and stromal cells by inducing proliferation. Most splenic HSCs were adjacent to Tcf21+ stromal cells in red pulp. Conditional deletion of Scf from spleen endothelial cells or Scf or Cxcl12 from Tcf21+ stromal cells severely reduced spleen EMH and reduced blood cell counts without affecting bone marrow hematopoiesis. Endothelial cells and Tcf21+ stromal cells thus create the splenic EMH niche, which is necessary for the physiological response to diverse hematopoietic stresses.
Project description:Neutrophil homeostasis is maintained, in part, by the regulated release of neutrophils from the bone marrow. Constitutive expression of the chemokine CXCL12 by bone marrow stromal cells provides a key retention signal for neutrophils in the bone marrow through activation of its receptor CXCR4. Herein, we show that the ELR chemokines CXCL1 and CXCL2 are constitutively expressed by bone marrow endothelial cells and osteoblasts, and CXCL2 expression is induced in endothelial cells during granulocyte colony-stimulating factor (G-CSF)-induced neutrophil mobilization. Neutrophils lacking CXCR2, the receptor for CXCL1 and CXCL2, are preferentially retained in the bone marrow, reproducing a myelokathexis phenotype. Transient disruption of CXCR4 failed to mobilize CXCR2 neutrophils. However, doubly deficient neutrophils (CXCR2-/- CXCR4-/-) displayed constitutive mobilization, showing that CXCR4 plays a dominant role. Collectively, these data suggest that CXCR2 signaling is a second chemokine axis that interacts antagonistically with CXCR4 to regulate neutrophil release from the bone marrow. We used gene expression microarrays to determine the changes in osteoblasts and bone marrow endothelial cells after G-CSF treatment.
Project description:We generated non-senescent, macrophage colony stimulating factor (M-CSF) dependent macrophages from murine fetal livers. These fetal liver macrophages (FLM-M) resemble bone marrow macrophage (BMM) morphology and express similar macrophage surface markers as BMM. In comparison to granulocyte monocyte-colony stimulating factor (GM-CSF) derived FLM (FLM-G), FLM-M have higher surface expression of CD11b, CD68, CD14 and CD64, and lower expression of CD11c. BMM, FLM-M and FLM-G all produce TNFα and IL-6 in response to lipopolysaccharide activation. BMM and FLM-M cells have similar phagocytic properties with 99.3% of BMM and FLM-M actively phagocytosing opsonized sheep erythrocytes and a phagocytic efficiency of 0.9. The average number of internalized erythrocytes per cell was higher (13.1±10.0) in BMM than in FLM-M (7.6±2.9). FLM-G had fewer actively phagocytic cells (86%), lower phagocytic efficiency (0.7) and fewer internalized erythrocytes per macrophage (4.2±2.1) than BMM or FLM-M. Principal component analysis and hierarchical clustering demonstrated mRNA expression profiles were more similar between BMM and FLM-M cells than FLM-G. Transcriptome comparison to the ImmGen tissue atlas shows cultured BMM and FLM-M cluster with macrophage progenitors and bone marrow macrophages. In conclusion, FLM-M cell cultures share major morphological, phenotypic and functional properties of BMM except for senescence, and can be an effective substitute to BMM. These new cells will facilitate study of macrophage biology by enabling experiments requiring long-term culture or genetic modifications.
Project description:Granulocyte-Macrophage colony stimulating factor (GM-CSF) devlops heterogenous myeloid cell populations from bone marrow progenitor cells. In vitro generated bone marrow derived cells are excellent sources for obtaining dendritic cells or macrophages, but it is still not clear about the exact mixed population characteristics of GM-CSF grown cells. We revealed here that GM-CSF grown bone marrow cell derived attaching cells were composed of dendritic cells (GM-BMDC) as well as macrophages (GM-BMM). We compared the transcriptome profiles of these cell populations as well as M-CSF grown bone marrow derived macrophages (M-BMM). We used microarrays to detail the global profile of gene expressions between three populations of CSF-grown bone marrow derived cells: GM-CSF derived dendritic cells (GM-BMDC), GM-CSF derived macrophages (GM-BMM) and M-CSF derived macrophages (M-BMM).