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J C Gasson

Publications and source records attributed to J C Gasson.

At least 37 records · Page 2Linked to original sources
PubMed1994

Signal transduction by granulocyte-macrophage colony-stimulating factor and interleukin-3 receptors.

Granulocyte-macrophage colony stimulating factor (GM-CSF) and Interleukin-3 (IL-3) are cytokines which stimulate myeloid bone marrow progenitor cell proliferation and maturation. GM-CSF also enhances the function of terminally differentiated effector cells including neutrophils, monocytes and eosinophils. Both growth factors exhibit similar biological activities on overlapping cell populations which are mediated by high affinity receptors. These receptors share a common beta subunit necessary for signal transduction. The receptors for GM-CSF and IL-3 are members of the hematopoietin receptor superfamily and consequently lack intrinsic tyrosine kinase activity. Several kinases, including JAK2 and raf-1, and other downstream molecules are likely to be responsible for the functional redundancy demonstrated by GM-CSF and IL-3 in factor-responsive cells. This review discusses recent findings which elucidate the signaling pathways activated by these two cytokines.

Amino Acid Sequence↗
PubMed1993

Identification and characterization of a high-affinity granulocyte-macrophage colony-stimulating factor receptor on primary rat oligodendrocytes.

We previously showed the presence of receptors for granulocyte-macrophage colony-stimulating factor (GM-CSF) on tumor tissues and tumor cell lines that are derived from the neural crest. To determine whether normal neural cells express functional GM-CSF receptors, we isolated and analyzed primary rat brain cells, including microglia, astrocytes, and oligodendrocytes. Scatchard analysis of equilibrium binding of 125I-GM-CSF to primary rat oligodendrocytes showed an average of 1,110 GM-CSF binding sites per cell, with a kd of 20 pmol/L. In six separate experiments, no specific binding was detectable on the astrocyte population. Microglia were used in competitive binding experiments with oligodendrocytes, and addition of microglia did not increase the specific binding of labeled ligand to oligodendrocytes. In dose-response assays, we measured 3H-thymidine uptake in rat oligodendrocytes, microglia and control murine 32D cells stimulated with various concentrations of GM-CSF. Over concentration ranges of 0.025 to 1000 pmol/L, cell proliferation and peak 3H-thymidine incorporation was observed at approximately 30 pmol/L for both the control cells and the oligodendrocytes. However, the microglial cells did not proliferate in response to GM-CSF. These data indicate the presence of a functional receptor for GM-CSF on primary rat oligodendrocytes, and suggest that hematopoietic growth factors such as GM-CSF may play a role in nerve cell development, function, or response to injury.

Animals↗
PubMed1993

Phenotypic characterization of the human fibrous histiocytoma giant cell tumor (GCT) cell line and its cytokine repertoire.

The pleiotropic nature of malignant fibrous histiocytomas (MFH) is manifested as mixed cellular infiltrates consisting of myofibroblasts, histiomonocytes, and neutrophils. We detail in this report the phenotypic characteristics of the human fibrous histiocytoma giant cell tumor (GCT) cell line that establish its mesenchymal origin. The latter is underscored by the ability of GCT cells to express mRNA for transforming growth factor beta (TGF-beta) as well as both A and B chains of platelet-derived growth factor (PDGF). GCT cells also support the binding of CD34+ cells, but less efficiently than do normal marrow stromal cells. Since cytokines elaborated by MFH may mediate in part the recruitment of monocytes and neutrophils into tumor-infiltrated tissues, we have determined the cytokine repertoire of the GCT cell line, already known for its ability to elaborate colony-stimulating factors (CSFs) and interleukin-1 (IL-1). GCT cells express IL-1 alpha, IL-1 beta, IL-6, macrophage colony-stimulating factor (M-CSF or CSF-1), granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), and IL-8. No detectable mRNA for IL-3, IL-4, IL-7, and tumor necrosis factor-alpha (TNF-alpha) was detected in GCT cells by polymerase chain reaction (PCR). Expression of cytokine mRNAs was responsive to agents such as dexamethasone (dex), 12-O-tetradecanoyl phorbol 13-acetate (phorbol diester or TPA), and TNF-alpha. Thus, this cell line provides a useful model for understanding the pathobiology of MFH and hematopoietic progenitor interactions with mesenchymal/stromal cells.

Cytokines↗
PubMed1992

HTLV-I and HTLV-II tax trans-activate the human EGR-1 promoter through different cis-acting sequences.

The immediate-early response gene, EGR-1, encodes a zinc finger-containing transcription factor that is involved in growth and differentiation of a variety of cell types. EGR-1 is induced in normal T cells following mitogenic stimulation and has recently been shown to be constitutively expressed in human T-cell leukemia virus type I (HTLV-I)- and type II (HTLV-II)-transformed T-cell lines. The trans-activating protein of HTLV-I, Tax, has been demonstrated to trans-activate promoters of a number of cellular genes, some of which may be critical in regulating T-cell proliferation. In this study, we examine the effect of Tax on expression of EGR-1 in three T-cell lines and demonstrate that both HTLV-I and -II Tax are capable of trans-activating human EGR-1 recombinant promoter constructs. Interestingly, HTLV-I and -II Tax trans-activate the human EGR-1 promoter through different promoter regions in the Jurkat cell line, suggesting that HTLV-I and -II Tax may lead to constitutive expression of EGR-1 through different signaling pathways. Deregulated expression of EGR-1 may contribute to uncontrolled cell growth and transformation during early stages of T-cell activation in HTLV-I and -II-infected cells.

Base Sequence↗
PubMed1991

Identification and characterization of a low-affinity granulocyte-macrophage colony-stimulating factor receptor on primary and cultured human melanoma cells.

Hematopoietic growth factor receptors are present on cells of normal nonhematopoietic tissues such as endothelium and placenta. We previously demonstrated functional human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors on small cell carcinoma of the lung cell lines, and others have reported that certain solid tumor cell lines respond to GM-CSF in clonogenic assays. In the current study, we examine human melanoma cell lines and fresh specimens of melanoma to determine whether they have functional GM-CSF receptors. Scatchard analyses of 125I-GM-CSF equilibrium binding to melanoma cell lines showed a mean of 542 +/- 67 sites per cell with a kd of 0.72 +/- 0.14 nmol/L. Cross-linking studies in the melanoma cell line, M14, showed a major GM-CSF receptor species of 84,000 daltons. Under the conditions tested, the M14 cells did not have a proliferative response to GM-CSF in vitro, nor was any induction of primary response genes detected by Northern analysis in response to GM-CSF. Studies to determine internal translocation of the receptor-ligand complex indicated less than 10% of the 125I-GM-CSF internalized was specifically bound to receptors. Primary melanoma cells from five surgical specimens had GM-CSF receptors; Scatchard analysis was performed on one sample, showing 555 sites/cell with a kd of 0.23 nmol/L. These results indicate that human tumor cells may express a low-affinity GM-CSF receptor protein that localizes to the cell surface and binds ligand, but lacks functional components or accessory factors needed to transduce a signal.

Cell Line↗
PubMed1991

Characterization of the soluble human granulocyte-macrophage colony-stimulating factor receptor complex.

The human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor (GM-R) is expressed on both hematopoietic and non-hematopoietic tissues. Although the receptor has been identified by cross-linking studies as an 84,000-dalton protein, very little is known about its biochemistry. In this report, we describe a soluble binding assay for the human GM-R which allowed us to characterize the receptor complex from various sources, including plasma membranes of placenta, neutrophils, and human myeloid leukemia cell lines. Preparation of membranes as well as solubilization by Triton X-100 and N-octylglucoside resulted in a 5-10-fold lower affinity of the receptor for GM-CSF. The Kd decreased from 20 to 80 pM in intact cells to 200-500 pM in both intact and solubilized membranes. Binding in solution was rapid, specific for GM-CSF, and best fit a "one-site" model with an approximate Kd of 500 pM. The dissociation rate constant for the soluble GM-R was very similar to that of intact cells (k2 = 0.013 min-1 versus 0.017 min-1, respectively). As expected, solubilized membranes obtained from those cells expressing the highest number of GM-R (neutrophils and dimethyl sulfoxide-induced HL-60 cells; approximately 500-800 sites/cell) possessed the highest concentration of soluble GM-R (approximately 2-3 x 10(8) GM-R/micrograms). Cross-linking of 125I-GM-CSF to soluble GM-R resulted in the appearance of two specifically labeled complexes. A major 110-kDa receptor-ligand complex is found when cross-linking is performed with intact cells; both 110- and 200-kDa species are seen when cross-linking is performed with either intact membranes or soluble GM-R. These studies define methods by which intact GM-R can be solubilized and measured in solution, permitting a more complete biochemical characterization of the intact GM-R complex.

Cell Line↗
PubMed1991

Clinical applications of human granulocyte-macrophage colony-stimulating factor.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor that stimulates myeloid cell proliferation and maturation and enhances the function of terminally differentiated effector cells. Phase I and II clinical trials have demonstrated mild to moderate toxicities at doses of less than 30 micrograms/kg/day. These studies suggest a potential role for this growth factor to stimulate myelopoiesis in patients with aplastic anemia, myelodysplastic syndromes, AIDS, chemotherapy-induced myelosuppression, chronic neutropenia, and following bone marrow transplantation. The potential clinical uses of GM-CSF will depend on results of studies designed to optimize its therapeutic efficacy.

Acquired Immunodeficiency Syndrome↗
PubMed1991

The biology and clinical applications of granulocyte-macrophage colony-stimulating factor.

GM-CSF is a hematopoietic growth factor that regulates myeloid cell proliferation and maturation and enhances the function of terminally differentiated effector cells. Results of clinical trials with GM-CSF in a number of disease states suggest a potential role of this growth factor to stimulate hematopoiesis. Future use of GM-CSF will depend on further studies to optimize its therapeutic efficacy.

Biology↗
PubMed1991

5' upstream sequence and genomic structure of the human primary response gene, EGR-1/TIS8.

EGR-1/TIS8 is a primary response gene that encodes a zinc finger containing protein and is induced in a number of cell types by a variety of ligands. We have isolated and mapped the human EGR-1/TIS8 gene and sequenced the 5' upstream flanking region. A 'TATA' homology and several putative regulatory elements, including two Sp1 sites, five serum response-like elements, two cAMP response-like elements, an EGR-1 binding site (EBS), and a tetra-decanoyl phorbol acetate (TPA)-responsive element have been identified within 700 nucleotides of the upstream region. We demonstrated that a 500-base pair fragment, which includes several of these possible regulatory sequences, is functional and responsive to TPA in transient transfection assays. A further understanding of the regulation and function of human EGR-1/TIS8 gene expression may provide insight into the mechanisms that control normal and neoplastic proliferation of human cells.

Animals↗
PubMed1990

Human granulocyte colony-stimulating factor: biologic activities and receptor characterization on hematopoietic cells and small cell lung cancer cell lines.

Human granulocyte colony-stimulating factor (G-CSF) is a regulatory glycoprotein that stimulates the production of neutrophilic granulocytes from committed hematopoietic progenitor cells both in vitro and in vivo. In this report, we show that biosynthetic (recombinant) human G-CSF enhances colony formation by normal human bone marrow and the human myeloid leukemic cell lines, HL-60 and KG-1, as well as nonhematopoietic small cell lung cancer lines, H128 and H69. G-CSF also modulates multiple differentiated functions of human neutrophils, including enhanced oxidative metabolism in response to f-Met-Leu-Phe (f-MLP), increased antibody-dependent cell-mediated cytotoxicity (ADCC), and augmented arachidonic acid release in response to ionophore and chemotactic agents. These effects are all maximal at a concentration of 100 to 500 pmol/L. Using 125I-labeled recombinant human G-CSF, high affinity binding sites were identified on human neutrophils, the myeloid leukemia cell lines KG-1 and HL-60, and the small cell carcinoma cell lines, H128 and H69. G-CSF receptor numbers ranged between 138 and 285 sites per cell with a kd of 77 to 140 pmol/L, consistent with the concentrations of G-CSF that elicit biologic responses in vitro. Decreased specific binding of 125l-G-CSF by human neutrophils was consistently observed in the presence of excess unlabeled human granulocyte-macrophage colony-stimulating factor (GM-CSF), suggesting competition or down modulation by GM-CSF of the G-CSF receptor.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1990

Recombinant human erythroid potentiating activity enhances the effect of erythropoietin in mice.

Endotoxin-free purified recombinant human erythroid potentiating activity (EPA) was administered to mice either alone or concomitantly with recombinant human erythropoietin (Epo). Epo treatment alone caused an increased hematocrit and reticulocyte count in the peripheral blood. In the spleen, the number of morphologically recognizable erythroid cells, CFU-E and BFU-E was also increased. Concomitant administration of EPA with Epo further enhanced erythropoiesis as judged by the same parameters. No significant effect on granulopoiesis was observed in association with Epo or combined Epo and EPA treatment. Our data indicates that EPA is active in vivo in augmenting the erythropoietic response to Epo.

Animals↗
PubMed1990

Human granulocyte-macrophage colony-stimulating factor (GM-CSF): regulation of expression.

GM-CSF is a potent hematopoietic growth factor which exerts its effects on hematopoietic cell growth both in vivo and in vitro. In addition, GM-CSF has profound effects enhancing the functional activity of circulating effector cells. GM-CSF can be produced by a variety of cell types in response to immune stimuli; both T-cells and macrophages produce GM-CSF upon activation. Furthermore, activated macrophages secrete IL-1 and TNF, which can stimulate GM-CSF production by certain types of endothelial and fibroblast cells. This local production of GM-CSF could then act on circulating neutrophils, monocytes and eosinophils to enhance their functions in host defense. Thus, one can envision a paracrine system in which the production of GM-CSF is sensitive to immune stimulation, and as a result of GM-CSF production, effector cells are recruited and their activities enhanced (Figure 4). The role of GM-CSF and other CSFs and interleukins in the homeostatic control of hematopoiesis is the subject of intense investigation. Careful integration of molecular and biological studies should yield exciting new information about both the physiologic and therapeutic roles of GM-CSF.

Base Sequence↗
PubMed1989

Multiple mechanisms control the expression of granulocyte-macrophage colony-stimulating factor by human fibroblasts.

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) has in vitro and in vivo effects on hemopoiesis and enhances the function of circulating mature myeloid cells. Unstimulated fibroblasts show low level GM-CSF transcription but no accumulation of GM-CSF mRNA or protein, whereas fibroblasts stimulated by TNF-alpha, IL-1, and phorbol diester have been shown to produce and secrete GM-CSF. To determine the mechanisms controlling the expression of GM-CSF in human fibroblasts, we used a transient transfection assay to look at the effect of TNF-alpha, IL-1 and phorbol diester on GM-CSF promoter sequences. Our results demonstrate that the phorbol diester, 12-O-tetradecanoylphorbol 13-acetate, can stimulate GM-CSF transcription via sequences located within 53 bp upstream of the GM-CSF cap site. TNF-alpha and IL-1 had no effect on GM-CSF transcription, suggesting that these cytokines act predominantly post-transcriptionally to stimulate production of GM-CSF. Our results demonstrate that multiple mechanisms can be used by human fibroblasts to produce GM-CSF in response to various inflammatory stimuli.

Base Sequence↗
PubMed1989

Genetic analysis of the human tumor necrosis factor alpha/cachectin promoter region in a macrophage cell line.

The 615-bp 5' flanking region of the human TNF-alpha/cachectin gene was isolated and ligated to the luciferase reporter gene. In addition, a series of truncated promoter constructs was generated by exonuclease III digestion. The promoter activity of these constructs was studied in a transient transfection system using the TNF-alpha-producing U937 cell line. Full-length and truncated TNF promoter constructions extending from -615 to -95 bp relative to the transcription start site (TSS) could be induced by phorbol esters. A construct truncated to within 36 bp of the TSS (and within 11 bp of the TATAA box) was inactive. Therefore, the phorbol ester responsive is localized in the TNF/cachectin promoter to a relatively short region proximal to the TATAA box.

Base Sequence↗
PubMed1989

Colony-stimulating factors and host defense.

Colony-stimulating factors are growth factors responsible for the proliferation and the maturation of bone marrow stem cells to fully differentiated granulocytes and monocytes. In addition to their effects on hematopoiesis, some colony-stimulating factors prime mature cells for enhanced chemotaxis, phagocytosis, and killing in response to physiologic stimuli. The action of colony-stimulating factors is mediated by growth factor receptors on precursor and mature effector cells. The results of studies of granulocyte-macrophage colony-stimulating factors in patients with the acquired immunodeficiency syndrome (AIDS) suggest a possible therapeutic role for colony-stimulating factors in augmenting mechanism of host defense.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Granulocyte-macrophage colony-stimulating factor and tetradecanoyl phorbol acetate induce a distinct, restricted subset of primary-response TIS genes in both proliferating and terminally differentiated myeloid cells.

Induction of early-response genes (tetradecanoyl phorbol acetate [TPA]-induced sequences, or TIS genes; R.W. Lim, B.C. Varnum, and H.R. Herschman, Oncogene 1:263-270, 1987) by granulocyte-macrophage colony-stimulating factor (GM-CSF) and TPA was examined both in a factor-dependent murine cell line, 32D clone 3, and in mature human neutrophils. When GM-CSF-deprived 32D clone 3 cells were exposed to GM-CSF or to TPA, four TIS mRNAs (TIS7, TIS8, TIS10, and TIS11) were rapidly and transiently induced. However, neither GM-CSF nor TPA could induce accumulation of TIS1 mRNA in 32D clone 3 cells, even under superinducing conditions. Both GM-CSF and TPA also elicited rapid, transient expression of TIS8 and TIS11 mRNA in postmitotic human neutrophils. However, neither agent could induce accumulation of TIS1 mRNA in human neutrophils. TIS1 is a member of the nuclear receptor supergene family that codes for ligand-dependent transcription factors. Cell-type restriction of inducible transcription factors may contribute to developmental specification.

Bone Marrow Cells↗