[A particular morphological change in the nucleus of leukemic hemocytoblasts and myeloblasts].
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Bone Marrow↗
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Results for “Granulocyte Precursor Cells”
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Cell multiplication, virus liberation, and ultrastrcuture of avain myeloblasts in tissue culture.
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Animals↗
Granulopoiesis in anemic Belgrade laboratory (b/b) rats.
The aim of this study was to clarify the nature of the abnormalities of granulopoiesis in anemic b/b rats. The size of different granulocytic cell compartments (granulocytic and macrophage precursor cells, proliferative and nonproliferative morphologically recognizable granulocytic cells) in the bone marrow, spleen, and peripheral blood was determined, and activity of granulocytic stimulators (colony-stimulating activities derived from lung-conditioned medium of endotoxin-treated rats and from spleen cells stimulated in vitro with pokeweed mitogen) was investigated. Depressed bone marrow granulopoiesis and expanded granulopoiesis in the spleen, together with the sustained production of granulocytic stimulators, was found in anemic b/b rats. It is suggested that the changes within the bone marrow microenvironment are the essential cause of disturbances of granulopoiesis in anemic b/b rats. The increased proliferation of granulocytic cells in iron-treated b/b rats indicates a role of iron in the cellular proliferation.
Anemia↗
Molecules stimulating early red cell, granulocyte, macrophage, and megakaryocyte precursors in culture: similarity in size, hydrophobicity, and charge.
Molecules in conditioned medium from stimulated lymphocyte populations or from certain cell lines are known to stimulate cells committed to various hemopoietic lineages as well as pluripotential cells to form colonies in culture. In this study, the relationship between molecules active on pluripotential cells and early cells committed to granulocyte, macrophage, megakaryocyte, or red cell production was explored using techniques of chemical separation. After separation on the basis of charge, or after sequential purification using methods of high resolving power based on hydrophobicity and size, these activities remained associated with one another. The observations provide support for a model which proposes that pluripotential hemopoietic precursor cells as well as their early committed progeny may all be responsive to a single lineage-indifferent factor. Responsiveness to "lineage-specific" factors such as erythropoietin is proposed to be a feature only of later cells after they have made the appropriate receptors as part of their differentiation program.
Animals↗
Effects of interleukin-3 on murine fetal liver hemopoiesis in utero.
The normal regulation of primitive hemopoietic stem cells (PHSCS) throughout development involves locally produced factors and humoral factors. While considerable information is available on the effects of candidate hemopoietic growth factors (HGFs) on postnatal hemopoietic tissues, little is known about the regulatory events of developing hemopoietic stem cells within fetal microenvironments. Fetal hemopoiesis represents expanding populations and may be under different regulatory control mechanisms. The microinjection of purified interleukin-3 (IL-3), a candidate HGF, into 13-day-old mouse fetuses via the yolk sac, allowed us to evaluate its effects on morphogenetic events and, more specifically, on fetal liver populations using quantitative in vitro clonal assays for hemopoietic precursors. In view of the sensitivity of fetal development during the early organogenetic period, considerable care was taken to identify the stress effects of the surgical laparotomy and the microinjection procedure. Control studies, required to distinguish stress effects of surgical laparotomy and microinjection, clearly revealed that the fetal liver is a sensitive organ responding with limited tissue disorganization, reduced cellularity and erythropoietic activity, as monitored 24 h after experimental intervention. The microinjection of 15 units of IL-3 promoted a significant expansion of depleted liver hemopoietic-cell populations and had stimulatory effects on the distribution of connective tissue mast cells and absolute cell numbers, including hemopoietic precursors (erythroid, granulocyte, macrophage, megakaryocyte), compared to controls. These studies suggest that (1) fetal liver hemopoiesis is selectively sensitive to maternal stress but has an effective regenerative capacity to maintain essential hemopoiesis in utero, and (2) fetal hemopoietic cells require an ability to respond to IL-3 early in fetal development.
Animals↗
Macromolecules stimulating human granulocytic colony-forming cells, precursors of these cells, and primitive erythroid progenitors: some apparent nonidentities.
The relationship between molecules having granulocyte colony-stimulating activity (G-CSA), erythroid burst-promoting activity (E-BPA), and activity promoting increase in the number of granulocytic progenitors in liquid culture (delta GPA) was explored in conditioned medium from human leukocytes (HLCM) and human placenta (HPCM). As tested on human hemopoietic progenitors in culture, G-CSA eluted from Sephadex G100 as a single peak with apparent molecular weight of 25,000, separating partially from E-BPA and delta GPA, which both had an apparent molecular weight of 45,000. All three activities eluted together from hydroxyapatite at low molarity phosphate. Their charge properties were also similar and all three electrofocused in flat gel beds in the pH range near 5.4. On both hydroxyapatite and isoelectric focusing, delta GPA sometimes separated partially from the other two activities but not consistently. The gel filtration result shows that in conditioned medium of human origin, molecules having G-CSA are not the same as those having delta GPA, suggesting a dual factor requirement in the granulocytic lineage reminiscent of that in the erythroid pathway. The results suggesting that delta GPA might differ from E-BPA, on the other hand, were not consistent enough to establish their nonidentity. Single micromanipulated cells proved capable of forming erythroid or granulocytic colonies in the presence of either crude or partially purified activity. The results establish that human colony-forming cells are direct primary targets of growth factors in HLCM and HPCM.
Chromatography↗
Role of stem cells in adaptation to hypoxia and mechanisms of neuroprotective effect of granulocytic colony-stimulating factor.
The role of regional cerebral neural precursor cells in restoration of the CNS activity during the development of hypoxic encephalopathy and the participation of the bone marrow mesenchymal stem cells in the formation of blood system reactions in hypoxia are shown. The mechanisms of neuroprotective effect of granulocytic colony-stimulating factor in severe oxygen insufficiency are studied. The specific psychopharmacological effect of granulocytic colony-stimulating factor is due to mobilization and determined homing of the bone marrow mesenchymal stem cells in damaged CNS zones with subsequent differentiation of these cells into specialized elements and due to activation of erythropoiesis.
Animals↗
Human myeloid precursors forming colonies in diffusion chambers expresses the Ia-like antigen.
Normal human bone marrow contains cells capable of forming myeloid colonies (CFU-DG) in fibrin clots in diffusion chambers placed in the peritoneal cavity of cyclophosphamide-treated mice. Evidence has accumulated indicating that these colony-forming cells represent an earlier stem cell than the granulocyte-monocyte precursor cell (CFU-C) assayed in soft agar. We provide data showing that these stem cells express the "Ia-like" or DR antigen. In the presence of rabbit Ia antiserum at a titer of 1:300, all CFU-DG were inhibited. Cytotoxicity was complement-dependent. Data are also presented that suggest that the megakaryocyte stem cell also expresses the Ia antigen.
Absorption↗
[Cell composition of umbilical cord blood in complicated and uncomplicated pregnancy].
Possible influence of most frequently encountered types of pathology during pregnancy on the cell composition of umbilical cord blood was studied. These pathologies included: treated iron-deficiency anemia, essential hypertension, threatening spontaneous abortion. A number and proliferative potential of granulocyte-macrophage precursor cells of umbilical cord blood were studied by agar drop-liquid media culture method. It was found that the types of pathology studied do not influence cell composition, number and proliferative potential of granulocyte-macrophage precursor cells from umbilical cord blood. These results show that umbilical cord blood after pathological pregnancy can be considered as a source of transplantable hemopoietic cells.
Case-Control Studies↗
Spleen colony-forming cell as common precursor for tissue mast cells and granulocytes.
The haematopoietic stem cells which produce colonies in the spleen of irradiated mice (CFU-S) can differentiate into erythrocytes, granulocytes, megakaryocytes and B lymphocytes. Although mast cell precursors are known to be present in the bone marrow, spleen, fetal liver and peripheral blood of mice, the relationship between the mast cell precursor and CFU-S has remained unclear. We have now made use of mice of two mutant genotypes to determine whether or not the tissue mast cell is a progeny of CFU-S. Giant granules of beige (C57BL/6-bg/bg, Chediak-Higashi syndrome) mice can be used for identification of the origin of both tissue mast cells and granulocytes, and WBB6F1-W/Wv mice are useful recipients because they lack tissue mast cells owing to a defect in mast cell precursors. We injected the cells from a single spleen colony into each WBB6F1-W/Wv mouse and demonstrated directly that the tissue mast cell is a progeny of CFU-S.
Animals↗
Human granulocyte surface molecules identified by murine monoclonal antibodies.
We have investigated the nature of the antigens recognized by four classes of mouse anti-human monoclonal antibodies that characteristically reacted with neutrophilic granulocytes and their precursor cells, but not with monocytes or other normal hemopoietic cells. The antigenic targets of the majority (9/12) of the independently isolated monoclonal antibodies were present on two surface glycoproteins (Mr 145,000 and 105,000) and glycolipids. This antigen(s) was also detected on granulocyte precursor cells, including the bone marrow granulocyte/monocyte progenitor cells (CFU-GM). The same antigen(s) detected by these monoclonal antibodies was also present in non-hemopoietic cell lines (colon carcinoma and neuroblastoma). Three other antigens, defined by monoclonal antibodies AHN-8, L12.2, and L13.1 and present on granulocytes and their mid-late precursor cells, could not be identified as proteins but were detected in a protein-free glycolipid extract of these cells. The diversity of the antigens was confirmed by cross-competition experiments and by the identification of their different patterns of reactivity with cell lines and bone marrow cells.
Animals↗
Preferential inhibition of murine macrophage colony formation by prostaglandin E.
Murine bone marrow progenitor cells that gave rise to macrophage colonies in semisolid agar were found to be more sensitive to prostaglandins of the E series (PGE) than were precursor cells of granulocytes and megakaryocytes. Macrophage colonies themselves had different sensitivities to the molecule. Precursor cells of macrophages that formed colonies in the presence of a stimulating activity from L cells (L-cell CSA) were inhibited to 50% levels by 3 x 10(-9)-M PGE. Macrophage progenitor cells, which require both L-cell CSA and rat hemolysate for colony growth, were inhibited to the same level by 3 x 10(-7)-M PGE. Other colony types (granulocytes and megakaryocytes) were sensitive to PGE only at concentrations greater than 10(-6) M. Accordingly, addition of different PGE concentrations to the culture assay should allow easy detection of precursor cells with morphologically distinct end cells. The different sensitivities to PGE of two macrophage colony types of different maturation stages indicate that PGE may provide feedback to control macrophage formation by inhibiting proliferation and differentiation of immature monocytoid cells.
Animals↗
Granulocytic differentiation of normal hematopoietic precursor cells induced by transcription factor PU.1 correlates with negative regulation of the c-myb promoter.
Numerous transcription factors allow hematopoietic cells to respond to lineage- and stage-specific cytokines and/or to act as their effectors. The transcription factors PU.1 and c-Myb are essential for hematopoiesis, most likely acting at distinct stages of differentiation, but sharing a common set of target genes. To determine whether PU.1 and c-Myb are functionally interrelated, murine bone marrow (BM) cells and 32Dcl3 murine myeloid precursor cells were infected with a retrovirus carrying a PU.1 cDNA and assessed for myeloid colony formation and for granulocytic differentiation, respectively. Compared with noninfected normal BM cells or to cells infected with an empty virus, hematopoietic precursor cells expressing PU.1 formed an increased number of interleukin-3 (IL-3) and granulocyte colony-stimulating factor (G-CSF)-stimulated colonies. Moreover, granulocytic differentiation of 32Dcl3 cells constitutively expressing PU.1 was accelerated, as indicated by morphology and by expression of differentiation markers. Downregulation of c-Myb protein levels by expression of an antisense c-myb construct was also associated with a faster kinetics of 32Dcl3 granulocytic differentiation. Sequence analysis of the 5' flanking region of the c-myb gene revealed a consensus PU box at position +16 to +21 able to specifically interact in electrophoretic mobility shift assays with either bacterially synthesized PU.1 protein or whole cell extracts from differentiated 32Dcl3 cells. Transient expression of PU.1 in cotransfection assays in different cell lines resulted in inhibition of chloramphenicol acetyl transferase activity driven by different segments of the c-myb promoter. Moreover, such an effect was dependent on an intact PU box. Thus, the ability of PU.1 to potentiate terminal myeloid differentiation appears to involve downregulation of c-myb expression, an essential step during differentiation of hematopoietic precursor cells.
Animals↗
Persistent dose-dependent increases in cycling of haemopoietic precursor cells after irradiation.
Between 3 weeks and 36 months after irradiation of mice, there was a dose-dependent increased level of cycling in haemopoietic stem cells (CFU-S) and in granulocyte-macrophage precursor cells (GM-CFC). For CFU-S the percentage kill measured using the thymidine suicide technique increased from about 10% in controls to a high and persistent average level of about 45% after 10 Gy gamma-rays, and for GM-CFC the increase was from about 30% to about 50%.
Animals↗
[Content and proliferative activity of granulocyte and macrophage cell-precursors in mice].
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Animals↗
Association of alkaline-phosphatase-positive reticulum cells in bone marrow with granulocytic precursors.
In the bone marrow, an elaborate stroma forms the structural basis of the hemopoietic microenvironment. In this study, two different types of stromal cells were identified with certainty on tissue sections of intact bone marrow of rats and mice using light and electron microscopic histochemistry: (a) a fibroblast-type of reticulum cell which is characterized by having alkaline phosphatase associated with its plasma membrane. We refer to this cell as the alkaline-phosphatase-positive reticulum cell (Al-RC). It is closely associated with granulocytic precursors, particularly myeloblasts and neutrophilic promyelocytes. These reticulum cells may be found throughout the marrow but are concentrated near the endosteum. (b) a macrophage-type of reticulum cell which is characterized by its abundance of lysosomal acid phosphatase and is mainly associated with erythroid precursors (as observed by others). In contrast to the above-mentioned cell type, this latter cell was found to be distributed uniformly throughout the marrow. We speculate that the Al-RC are mesenchymal stromal cells necessary for granulocytic differentiation in bone marrow.
Acid Phosphatase↗
Expression of the cochaperone HspBP1 is not coordinately regulated with Hsp70 expression.
Intracellular levels of the heat stress protein Hsp70 are elevated following exposure to elevated temperature. The cochaperone HspBP1 is an intracellular protein that is known to bind to and regulate Hsp70 activity. The purpose of this study was to determine if HspBP1 levels changed when Hsp70 levels were altered. Heat stress resulted in an increase in Hsp70 levels but no change in HspBP1 levels. Treatment of cells with the apoptosis inducing drug camptothecin lowered Hsp70 levels but again had no effect on HspBP1 levels. Cells treated with camptothecin plus heat stress did not exhibit an increase in Hsp70 levels. Over-expression in cells stably transfected with HspBP1 cDNA resulted in a 290% increase in HspBP1 levels without a similar change in Hsp70 levels. These results demonstrate that Hsp70 and HspBP1 are not coordinately regulated but provide evidence that an increase in the ratio of HspBP1 to Hsp70 correlates with apoptosis, in a similar way to reducing the amount of Hsp70.
Adaptor Proteins, Signal Transducing↗
Posttransplant hematopoiesis in patients undergoing sibling allogeneic stem cell transplantation reflects that of their respective donors although with a lower functional capability.
We tested the principle of whether patient long-term hematopoiesis following allogeneic stem cell transplantation (allo-SCT) reflects the characteristics of the hematopoiesis of their respective donor. For this purpose, we analyzed bone marrow (BM) hematopoiesis using long-term cultures (LTC), delta assays, and clonogeneic assays as well as CD34+ cells and their subsets by flow cytometry in a series of 37 patients undergoing allo-SCT, and we compared it to that of their respective human leukocyte antigen-matched sibling donors in a paired study performed more than 1 year after the transplant procedure. Interestingly, the main factor that influenced post-allo-SCT BM hematopoiesis in the long term was donor hematopoiesis. Nevertheless, compared to their respective donors, patients exhibited a significantly lower number of colony-forming units granulomonocytic, burst-forming units erythroid, and immature progenitors (CD34++/CD38dim/CD90+/CD133+ cells, LTC-initiating cells, and colonies generated in the delta assay). Moreover, BM stromal function was diminished in patients undergoing allo-SCT compared to their donors. In addition, the presence of chronic graft-versus-host disease under immunosuppressive treatment also conditioned an impaired hematopoietic function. In summary, our study shows that BM hematopoiesis evaluated more than 1 year after an allo-SCT mainly reproduces that of their respective donors, although with a significantly decreased in vitro activity.
Adolescent↗