scholarly journals Alterations in differentiation and behavior of monocytic phagocytes in transgenic mice that express dominant suppressors of ras signaling.

1995 ◽  
Vol 15 (2) ◽  
pp. 693-703 ◽  
Author(s):  
D I Jin ◽  
S B Jameson ◽  
M A Reddy ◽  
D Schenkman ◽  
M C Ostrowski

To address the role of ras signaling in monocytic phagocytes in vivo, the expression of two dominant suppressors of in vitro ras signaling pathways, the carboxyl-terminal region of the GTPase-activating protein (GAP-C) and the DNA binding domain of the transcription factor ets-2, were targeted to this cell compartment. A 5-kb portion of the human c-fms proximal promoter was shown to direct expression of the transgenes to the monocytic lineage. As a result of the GAP-C transgene expression, ras-GTP levels were reduced in mature peritoneal macrophages by 70%. The terminal differentiation of monocytes was altered, as evidence by the accumulation of atypical monocytic cells in the blood. Mature peritoneal macrophages exhibited changes in colony-stimulating factor 1-dependent survival and structure. Further, expression of the colony-stimulating factor 1-stimulated gene urokinase plasminogen activator was inhibited in peritoneal macrophages. The results indicate that ras action is critical in monocytic cells after these cells have lost the capacity to traverse the cell cycle.

2001 ◽  
pp. 431-440 ◽  
Author(s):  
S Palacio ◽  
R Felix

BACKGROUND: Colony-stimulating factor-1 (CSF-1), a growth and survival factor for osteoclasts, stimulates these cells to spread and migrate towards a gradient of CSF-1. This may support the translocation of osteoclasts to new sites on the bone surface to be resorbed. Phosphoinositide 3-kinase (PI 3-K) is a lipid kinase participating in various signal transduction pathways. OBJECTIVE: To investigate the role of PI 3-K in the CSF-1-induced spreading of osteoclasts. METHODS: In isolated rat osteoclasts treated with or without CSF-1, the distribution of PI 3-K and proteins phosphorylated on tyrosine were investigated using immunofluorescence. In murine osteoclast-like cells grown from bone marrow cells co-cultured with osteoblasts, the activation of the PI 3-K by CSF-1 was determined both in vivo and in vitro. In vivo, the enzyme product in the cell was determined after extraction and separation with thin layer chromatography; in vitro, PI 3-K activity was measured in the pellet immunoprecipitated from the cell lysate. RESULTS: Inhibition of PI 3-K blocked the CSF-1-induced spreading of osteoclasts. In spreading osteoclasts, a portion of PI 3-K was translocated to the periphery where proteins phosphorylated on tyrosine appeared simultaneously. In osteoclast-like cells, CSF-1 stimulated PI 3-K activity. This activity could be immunoprecipitated with antibody against phophotyrosine residues. CONCLUSION: PI 3-K participates in the CSF-1-induced spreading of osteoclasts. The activated PI 3-K may induce the reorganization of the cytoskeleton resulting in spreading and migration.


Blood ◽  
1983 ◽  
Vol 62 (3) ◽  
pp. 693-696
Author(s):  
H Burlington ◽  
EP Cronkite ◽  
B Heldman ◽  
N Pappas ◽  
RK Shadduck

A transplantable granulocytosis-inducing mammary adenocarcinoma of mice was used to provide evidence about the role of tumor-generated factors in granulopoiesis. The original tumor produced high levels of colony- stimulating factor (CSF) in culture as well as inhibitor to CSF. The tumor was passaged repeatedly, both in host mice and in culture, and eventually displayed a varying capacity to induce granulocytosis. Tumors that were associated with either the induction of extreme granulocytosis or near-normal granulocyte levels were selected and passaged intermittently in vivo and in culture. Two tumor lines were thus isolated: one, line C-4a, inducing granulocytosis, and the other, line 34–4H, failing to induce granulocytosis. Both lines grow at the same rate in host mice, but in culture, each displays a distinct morphology. Measurement of CSF and inhibitor produced by each line in culture showed that line 34–4H retained the capacity to produce CSF and inhibitor in spite of losing the ability to influence granulopoiesis in vivo. This suggests that the various factors shown to influence granulopoiesis in vitro may have little or no role as physiologic regulators in vivo.


Blood ◽  
1983 ◽  
Vol 62 (3) ◽  
pp. 693-696 ◽  
Author(s):  
H Burlington ◽  
EP Cronkite ◽  
B Heldman ◽  
N Pappas ◽  
RK Shadduck

Abstract A transplantable granulocytosis-inducing mammary adenocarcinoma of mice was used to provide evidence about the role of tumor-generated factors in granulopoiesis. The original tumor produced high levels of colony- stimulating factor (CSF) in culture as well as inhibitor to CSF. The tumor was passaged repeatedly, both in host mice and in culture, and eventually displayed a varying capacity to induce granulocytosis. Tumors that were associated with either the induction of extreme granulocytosis or near-normal granulocyte levels were selected and passaged intermittently in vivo and in culture. Two tumor lines were thus isolated: one, line C-4a, inducing granulocytosis, and the other, line 34–4H, failing to induce granulocytosis. Both lines grow at the same rate in host mice, but in culture, each displays a distinct morphology. Measurement of CSF and inhibitor produced by each line in culture showed that line 34–4H retained the capacity to produce CSF and inhibitor in spite of losing the ability to influence granulopoiesis in vivo. This suggests that the various factors shown to influence granulopoiesis in vitro may have little or no role as physiologic regulators in vivo.


1990 ◽  
Vol 10 (6) ◽  
pp. 2991-3002
Author(s):  
P van der Geer ◽  
T Hunter

The receptor for colony-stimulating factor 1 (CSF-1) is a ligand-activated protein-tyrosine kinase. It has been shown previously that the CSF-1 receptor is phosphorylated on serine in vivo and that phosphorylation on tyrosine can be induced by stimulation with CSF-1. We studied the phosphorylation of the CSF-1 receptor by using the BAC1.2F5 murine macrophage cell line, which naturally expresses CSF-1 receptors. Two-dimensional tryptic phosphopeptide mapping showed that the CSF-1 receptor is phosphorylated on several different serine residues in vivo. Stimulation with CSF-1 at 37 degrees C resulted in rapid phosphorylation on tyrosine at one major site and one or two minor sites. We identified the major site as Tyr-706. The identity of Tyr-706 was confirmed by mutagenesis. This residue is located within the kinase insert domain. There was no evidence that Tyr-973 (equivalent to Tyr-969 in the human CSF-1 receptor) was phosphorylated following CSF-1 stimulation. When cells were stimulated with CSF-1 at 4 degrees C, additional phosphotyrosine-containing phosphopeptides were detected and the level of phosphorylation of the individual phosphotyrosine-containing phosphopeptides was substantially increased. In addition, we show that CSF-1 receptors are capable of autophosphorylation at six to eight major sites in vitro.


Blood ◽  
1997 ◽  
Vol 90 (7) ◽  
pp. 2583-2590 ◽  
Author(s):  
Fulu Liu ◽  
Jennifer Poursine-Laurent ◽  
Huai Yang Wu ◽  
Daniel C. Link

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.


1989 ◽  
Vol 35 (6) ◽  
pp. 647-652
Author(s):  
Akimichi Ohsaka ◽  
Seiichi Kitagawa ◽  
Akira Yuo ◽  
Takashi Obata ◽  
Youichi Amemiya ◽  
...  

2009 ◽  
Vol 6 (5) ◽  
pp. 387-392 ◽  
Author(s):  
Yinan Wang ◽  
Xueling Cui ◽  
Guixiang Tai ◽  
Jingyan Ge ◽  
Nan Li ◽  
...  

1990 ◽  
Vol 10 (4) ◽  
pp. 1664-1671
Author(s):  
M Ohtsuka ◽  
M F Roussel ◽  
C J Sherr ◽  
J R Downing

Ligand-induced tyrosine phosphorylation of the human colony-stimulating factor 1 receptor (CSF-1R) could involve either an intra- or intermolecular mechanism. We therefore examined the ability of a CSF-1R carboxy-terminal truncation mutant to phosphorylate a kinase-defective receptor, CSF-1R[met 616], that contains a methionine-for-lysine substitution at its ATP-binding site. By using an antipeptide serum that specifically reacts with epitopes deleted from the enzymatically competent truncation mutant, cross-phosphorylation of CSF-1R[met 616] on tyrosine was demonstrated, both in immune-complex kinase reactions and in intact cells stimulated with CSF-1. Both in vitro and in vivo, CSF-1R[met 616] was phosphorylated on tryptic peptides identical to those derived from wild-type CSF-1R, suggesting that receptor phosphorylation on tyrosine can proceed via an intermolecular interaction between receptor monomers. When expressed alone, CSF-1R[met 616] did not undergo ligand-induced down modulation, but its phosphorylation in cells coexpressing the kinase-active truncation mutant accelerated its degradation.


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