21 results on '"Whitty GA"'
Search Results
2. Macrophage colony-stimulating factor and granulocyte-macrophage colony- stimulating factor stimulate the synthesis of plasminogen-activator inhibitors by human monocytes
- Author
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Hamilton, JA, primary, Whitty, GA, additional, Stanton, H, additional, Wojta, J, additional, Gallichio, M, additional, McGrath, K, additional, and Ianches, G, additional
- Published
- 1993
- Full Text
- View/download PDF
3. Interleukin-4 suppresses plasminogen activator inhibitor-2 formation in stimulated human monocytes
- Author
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Hamilton, JA, primary, Whitty, GA, additional, Last, K, additional, Royston, AK, additional, Hart, PH, additional, and Burgess, DR, additional
- Published
- 1992
- Full Text
- View/download PDF
4. Activation of human monocytes by granulocyte-macrophage colony- stimulating factor: increased urokinase-type plasminogen activator activity
- Author
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Hart, PH, primary, Vitti, GF, additional, Burgess, DR, additional, Whitty, GA, additional, Royston, K, additional, and Hamilton, JA, additional
- Published
- 1991
- Full Text
- View/download PDF
5. Thrombin-cleaved osteopontin regulates hemopoietic stem and progenitor cell functions through interactions with alpha9beta1 and alpha4beta1 integrins.
- Author
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Grassinger J, Haylock DN, Storan MJ, Haines GO, Williams B, Whitty GA, Vinson AR, Be CL, Li S, Sørensen ES, Tam PP, Denhardt DT, Sheppard D, Choong PF, and Nilsson SK
- Subjects
- Animals, Base Sequence, CHO Cells, Cell Line, Chemotaxis drug effects, Chemotaxis physiology, Cricetinae, Cricetulus, DNA Primers genetics, Fetal Blood cytology, Gene Expression, Granulocyte Colony-Stimulating Factor pharmacology, Hematopoiesis drug effects, Hematopoiesis genetics, Hematopoiesis physiology, Hematopoietic Stem Cells drug effects, Humans, In Vitro Techniques, Integrin alpha4beta1 genetics, Integrins genetics, Mice, Mice, Inbred C57BL, Mice, Knockout, Mice, Transgenic, Osteopontin deficiency, Osteopontin genetics, Osteopontin pharmacology, Recombinant Proteins genetics, Recombinant Proteins metabolism, Thrombin metabolism, Hematopoietic Stem Cells cytology, Hematopoietic Stem Cells physiology, Integrin alpha4beta1 metabolism, Integrins metabolism, Osteopontin physiology
- Abstract
Osteopontin (OPN), a multifunctional acidic glycoprotein, expressed by osteoblasts within the endosteal region of the bone marrow (BM) suppresses the proliferation of hemopoietic stem and progenitor cells and also regulates their lodgment within the BM after transplantation. Herein we demonstrate that OPN cleavage fragments are the most abundant forms of this protein within the BM. Studies aimed to determine how hemopoietic stem cells (HSCs) interact with OPN revealed for the first time that murine and human HSCs express alpha(9)beta(1) integrin. The N-terminal thrombin cleavage fragment of OPN through its binding to the alpha(9)beta(1) and alpha(4)beta(1) integrins plays a key role in the attraction, retention, regulation, and release of hemopoietic stem and progenitor cells to, in, and from their BM niche. Thrombin-cleaved OPN (trOPN) acts as a chemoattractant for stem and progenitor cells, mediating their migration in a manner that involves interaction with alpha(9)beta(1) and alpha(4)beta(1) integrins. In addition, in the absence of OPN, there is an increased number of white blood cells and, specifically, stem and progenitor cells in the peripheral circulation.
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- 2009
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6. Hemopoietic stem cells with higher hemopoietic potential reside at the bone marrow endosteum.
- Author
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Haylock DN, Williams B, Johnston HM, Liu MC, Rutherford KE, Whitty GA, Simmons PJ, Bertoncello I, and Nilsson SK
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- Animals, Cell Division, Hematopoiesis, Mice, Mice, Inbred C57BL, Stem Cell Transplantation, Tissue and Organ Harvesting methods, Bone Marrow Cells cytology, Hematopoietic Stem Cells cytology, Hematopoietic Stem Cells physiology
- Abstract
It is now evident that hemopoietic stem cells (HSC) are located in close proximity to bone lining cells within the endosteum. Accordingly, it is unlikely that the traditional method for harvesting bone marrow (BM) from mice by simply flushing long bones would result in optimal recovery of HSC. With this in mind, we have developed improved methodologies based on sequential grinding and enzymatic digestion of murine bone tissue to harvest higher numbers of BM cells and HSC from the endosteal and central marrow regions. This methodology resulted in up to a sixfold greater recovery of primitive hemopoietic cells (lineage(-)Sca(+)Kit(+) [LSK] cells) and HSC as shown by transplant studies. HSC from different anatomical regions of the marrow exhibited important functional differences. Compared with their central marrow counterparts, HSC isolated from the endosteal region (a) had 1.8-fold greater proliferative potential, (b) exhibited almost twofold greater ability to home to the BM following tail vein injection and to lodge in the endosteal region, and (c) demonstrated significantly greater long-term hemopoietic reconstitution potential as shown using limiting dilution competitive transplant assays.
- Published
- 2007
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- View/download PDF
7. Osteopontin, a key component of the hematopoietic stem cell niche and regulator of primitive hematopoietic progenitor cells.
- Author
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Nilsson SK, Johnston HM, Whitty GA, Williams B, Webb RJ, Denhardt DT, Bertoncello I, Bendall LJ, Simmons PJ, and Haylock DN
- Subjects
- Animals, Bone Marrow chemistry, Cell Adhesion, Cell Movement, Cell Proliferation, Integrin beta1 metabolism, Mice, Mice, Knockout, Osteopontin, Sialoglycoproteins analysis, Sialoglycoproteins metabolism, Tissue Distribution, Hematopoiesis, Hematopoietic Stem Cells cytology, Sialoglycoproteins physiology
- Abstract
Although recent data suggests that osteoblasts play a key role within the hematopoietic stem cell (HSC) niche, the mechanisms underpinning this remain to be fully defined. The studies described herein examine the role in hematopoiesis of Osteopontin (Opn), a multidomain, phosphorylated glycoprotein, synthesized by osteoblasts, with well-described roles in cell adhesion, inflammatory responses, angiogenesis, and tumor metastasis. We demonstrate a previously unrecognized critical role for Opn in regulation of the physical location and proliferation of HSCs. Within marrow, Opn expression is restricted to the endosteal bone surface and contributes to HSC transmarrow migration toward the endosteal region, as demonstrated by the markedly aberrant distribution of HSCs in Opn-/- mice after transplantation. Primitive hematopoietic cells demonstrate specific adhesion to Opn in vitro via beta1 integrin. Furthermore, exogenous Opn potently suppresses the proliferation of primitive HPCs in vitro, the physiologic relevance of which is demonstrated by the markedly enhanced cycling of HSC in Opn-/- mice. These data therefore provide strong evidence that Opn is an important component of the HSC niche which participates in HSC location and as a physiologic-negative regulator of HSC proliferation.
- Published
- 2005
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8. A novel 110 kDa form of myosin XVIIIA (MysPDZ) is tyrosine-phosphorylated after colony-stimulating factor-1 receptor signalling.
- Author
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Cross M, Csar XF, Wilson NJ, Manes G, Addona TA, Marks DC, Whitty GA, Ashman K, and Hamilton JA
- Subjects
- Amino Acid Sequence, Animals, Cell Differentiation, Cell Line drug effects, Cell Line metabolism, Electrophoresis, Gel, Two-Dimensional, Gelsolin metabolism, Genes, fms, Heat-Shock Proteins metabolism, Isomerases metabolism, Macrophages drug effects, Mice, Molecular Sequence Data, Myeloid Cells metabolism, Myosins chemistry, Myosins isolation & purification, Nonmuscle Myosin Type IIA metabolism, Phosphorylation drug effects, Phosphotyrosine analysis, Protein Disulfide-Isomerases, Receptor, Macrophage Colony-Stimulating Factor drug effects, Recombinant Fusion Proteins physiology, Transfection, src-Family Kinases metabolism, Macrophage Colony-Stimulating Factor pharmacology, Myosins metabolism, Protein Processing, Post-Translational drug effects, Receptor, Macrophage Colony-Stimulating Factor physiology, Signal Transduction
- Abstract
Macrophage colony-stimulating factor (M-CSF or CSF-1) controls the development of macrophage lineage cells via activation of its tyrosine kinase receptor, c-Fms. After adding CSF-1 to M1 myeloid cells expressing CSF-1R (CSF-1 receptor), tyrosine phosphorylation of many cellular proteins occurs, which might be linked to subsequent macrophage differentiation. The biological significance and characterization of such proteins were explored by a dual strategy comprising two-dimensional SDS/PAGE analysis of cell lysates of CSF-1-treated M1 cells expressing the wild-type or a mutated receptor, together with an enrichment strategy involving a tyrosine-phosphorylated receptor construct. In the present study, we report the identification by MS of a novel, low-abundance, 110 kDa form of myosin XVIIIA (MysPDZ, myosin containing PDZ domain), which appears to be preferentially tyrosine-phosphorylated after CSF-1R activation when compared with other known isoforms. Receptor mutation studies indicate that CSF-1R-dependent tyrosine phosphorylation of p110myosin XVIIIA requires Tyr-559 in the cytoplasmic domain of the receptor and is therefore Src-family kinase-dependent. Gelsolin, Erp61 protein disulphide-isomerase and possibly non-muscle myosin IIA were also tyrosine-phosphorylated under similar conditions. Similar to the more abundant p190 isoform, p110 myosin XVIIIA lacks a PDZ domain and, in addition, it may lack motor activity. The phosphorylation of p110 myosin XVIIIA by CSF-1 may alter its cellular localization or target its association with other proteins.
- Published
- 2004
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9. The generation of highly enriched osteoclast-lineage cell populations.
- Author
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Quinn JM, Whitty GA, Byrne RJ, Gillespie MT, and Hamilton JA
- Subjects
- Animals, Bone Marrow Cells drug effects, Bone Resorption etiology, Bone Resorption pathology, Carrier Proteins pharmacology, Cell Differentiation drug effects, Cell Line, Coculture Techniques, Hematopoietic Stem Cells cytology, Hematopoietic Stem Cells drug effects, Macrophage Colony-Stimulating Factor pharmacology, Membrane Glycoproteins pharmacology, Mice, Mice, Inbred C57BL, Mice, Inbred CBA, Osteoclasts drug effects, RANK Ligand, Receptor Activator of Nuclear Factor-kappa B, Recombinant Proteins pharmacology, Tumor Necrosis Factor-alpha pharmacology, Bone Marrow Cells cytology, Osteoclasts cytology
- Abstract
Osteoclasts form when hematopoietic cells are stimulated by macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-kappaB ligand (RANKL) or tumor necrosis factor-alpha (TNFalpha). Osteoclast precursors derive from M-CSF-dependent proliferating hematopoietic cells but cannot yet be purified from mixed populations. M-CSF stimulation of bone marrow cells results in large numbers of nonadherent, proliferating macrophage precursors. These rapidly form adherent bone marrow macrophages (BMM). BMM and their precursors can be isolated free from mesenchymal and lymphocytic cells. BMM precursors derived from CBA-strain mouse bone marrow, when cocultured with ST2 cells (which express RANKL and M-CSF), formed numerous mononuclear osteoclasts, which resorbed bone and expressed tartrate-resistant acid phosphatase (TRAP) and calcitonin receptors (CTR). Addition of approximately 10 BMM precursors to ST2 cultures resulted in over 80% of these cocultures forming functional osteoclasts, suggesting that they are a highly enriched source of osteoclast progenitors. Supporting this, recombinant RANKL/M-CSF-stimulated BMM precursors formed populations in which all cells expressed TRAP. While only a small proportion of these cells (8.6%) expressed CTR, with transforming growth factor-beta (TGFbeta) present RANKL/M-CSF-stimulated BMM precursors formed almost pure (98.4%) CTR-positive osteoclasts after 7 days. This suggests that TGFbeta stimulated the maturation rate of these cells. Passaged or viably frozen BMM precursors gave rise to BMM that also all formed osteoclasts lineage cells after RANKL/M-CSF stimulation. These data suggest that BMM precursors derived from CBA mice are an expanded pool of osteoclast progenitors. These can be employed to generate osteoclast populations of high purity and in large numbers when stimulated by TGFbeta, which greatly augments the osteoclastogenic effects of RANKL.
- Published
- 2002
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- View/download PDF
10. Colony-stimulating factor-1 (CSF-1) receptor-mediated macrophage differentiation in myeloid cells: a role for tyrosine 559-dependent protein phosphatase 2A (PP2A) activity.
- Author
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McMahon KA, Wilson NJ, Marks DC, Beecroft TL, Whitty GA, Hamilton JA, and Csar XF
- Subjects
- Animals, Cell Differentiation, Cell Line, Enzyme Inhibitors pharmacology, Macrophages cytology, Mice, Mitogen-Activated Protein Kinase 1 metabolism, Mitogen-Activated Protein Kinase 3, Mitogen-Activated Protein Kinases metabolism, Mutation, Myeloid Cells drug effects, Okadaic Acid pharmacology, Phosphoprotein Phosphatases antagonists & inhibitors, Phosphorylation, Phosphotyrosine metabolism, Protein Phosphatase 2, Receptor, Macrophage Colony-Stimulating Factor genetics, Signal Transduction, Macrophages physiology, Myeloid Cells cytology, Phosphoprotein Phosphatases metabolism, Receptor, Macrophage Colony-Stimulating Factor chemistry, Receptor, Macrophage Colony-Stimulating Factor physiology
- Abstract
M1 myeloid cells transfected with the wild-type (WT) colony-stimulating factor-1 (CSF-1) receptor (CSF-1R; M1/WT cells) undergo CSF-1-dependent macrophage differentiation. By mutation studies, we have provided prior evidence that tyrosine 559 in the CSF-1R cytoplasmic domain governs the Src-dependent differentiation pathway. Further components of this pathway were then sought. We report that the extent of CSF-1-mediated tyrosine phosphorylation of protein phosphatase 2A (PP2A), and the associated loss of its activity were reduced in M1 cells transfected with the CSF-1R with a tyrosine-to-phenylalanine mutation at position 559 (M1/559 cells), compared with the corresponding responses in CSF-1-treated M1/WT cells. This evidence for an involvement of a reduction in PP2A activity in the differentiation process was supported by the restoration of the defect in the CSF-1-mediated differentiation of M1/559 cells by the addition of the PP2A inhibitor, okadaic acid. It was also found that the degree of activation of extracellular-signal-regulated kinase (ERK) activities by CSF-1 was reduced in M1/559 cells, suggesting their involvement in the differentiation process. These data suggest that PP2A and ERK form part of the Src-dependent signal-transduction cascade governing CSF-1-mediated macrophage differentiation in M1 cells.
- Published
- 2001
- Full Text
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11. Proteomic analysis of macrophage differentiation. p46/52(Shc) Tyrosine phosphorylation is required for CSF-1-mediated macrophage differentiation.
- Author
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Csar XF, Wilson NJ, McMahon KA, Marks DC, Beecroft TL, Ward AC, Whitty GA, Kanangasundarum V, and Hamilton JA
- Subjects
- Animals, Cell Differentiation drug effects, Cell Differentiation physiology, Cell Lineage physiology, Macrophage Colony-Stimulating Factor pharmacology, Macrophages cytology, Mice, Phosphorylation, Shc Signaling Adaptor Proteins, Src Homology 2 Domain-Containing, Transforming Protein 1, Tyrosine, Adaptor Proteins, Signal Transducing, Adaptor Proteins, Vesicular Transport, Macrophages physiology, Proteins physiology
- Abstract
Macrophage colony stimulating factor (M-CSF or CSF-1) acts to regulate the development and function of cells of the macrophage lineage. Murine myeloid FDC-P1 cells transfected with the CSF-1 receptor (FD/WT) adopt a macrophage-like morphology when cultured in CSF-1. This process is abrogated in FDC-P1 cells transfected with the CSF-1 receptor with a tyrosine to phenyalanine substitution at position 807 (FD/807), suggesting that a molecular interaction critical to differentiation signaling is lost (Bourette, R. P., Myles, G. M., Carlberg, K., Chen, A. R., and Rohrschneider, L. R. (1995) Cell Growth Differ. 6, 631--645). A detailed examination of lysates of CSF-1-treated FD/807 cells by two-dimensional SDS-polyacrylamide gel electrophoresis (PAGE) revealed a number of proteins whose degree of tyrosine phosphorylation was modulated by the Y807F mutation. Included in this category were three phosphorylated proteins that co-migrated with p46/52(Shc). Immunoprecipitation, Western blotting, and in vitro binding studies suggest that they are indeed p46/52(Shc). A key regulator of differentiation in a number of cell systems, ERK was observed to exhibit an activity that correlated with the relative degree of differentiation induced by CSF-1 in the two cell types. Transfection of cells with a non-tyrosine-phosphorylatable form of p46/52(Shc) prevented the normally observed CSF-1-mediated macrophage differentiation as determined by adoption of macrophage-like morphology and expression of the monocyte/macrophage lineage cell surface marker, Mac-1. These results are the first to suggest that p46/52(Shc) may play a role in CSF-1-induced macrophage differentiation. Additionally, a number of proteins were identified by two-dimensional SDS-PAGE whose degree of tyrosine phosphorylation is also modulated by the Y807F substitution. This group of molecules may contain novel signaling molecules important in macrophage differentiation.
- Published
- 2001
- Full Text
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12. Endogenous IFN-alpha beta suppresses colony-stimulating factor (CSF)-1-stimulated macrophage DNA synthesis and mediates inhibitory effects of lipopolysaccharide and TNF-alpha.
- Author
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Hamilton JA, Whitty GA, Kola I, and Hertzog PJ
- Subjects
- Animals, Cell Division drug effects, Cyclic AMP pharmacology, Female, In Vitro Techniques, Interferon-gamma pharmacology, Lipopolysaccharides pharmacology, Macrophage Colony-Stimulating Factor pharmacology, Macrophages drug effects, Male, Membrane Proteins, Mice, Mice, Inbred BALB C, Mice, Inbred CBA, Mice, Knockout, Receptor, Interferon alpha-beta, Receptors, Interferon genetics, Receptors, Interferon metabolism, Recombinant Proteins, Tumor Necrosis Factor-alpha pharmacology, DNA biosynthesis, Interferon-alpha metabolism, Interferon-beta metabolism, Macrophages immunology, Macrophages metabolism
- Abstract
Murine bone marrow-derived macrophages (BMM) are widely used as a suitable model to study the proliferative response to macrophage-CSF or CSF-1. We report here that the amount of DNA synthesis observed in BMM cultures in response to CSF-1 can be masked quite significantly by low levels of IFN-alpha beta produced in the cultures. It was found that Ab to IFN-alpha beta could enhance the proliferative response in CSF-treated BMM that were able to respond to endogenous IFN-alpha beta; however, BMM from mice lacking a component of the type I IFN receptor did not show any enhancement of CSF-1-dependent DNA synthesis on addition of the Ab. While DNA synthesis in CSF-1-stimulated BMM from normal mice was also very sensitive to the inhibitory actions of very low concentrations of added IFN-alpha beta, DNA synthesis in BMM from the "knockout" mice was not, indicating that the type I IFN receptor component containing the null mutation was essential for signal transduction. Previously it was shown that bacterial LPS, TNF-alpha, IFN-gamma, and cAMP could all inhibit CSF-1-stimulated BMM DNA synthesis and proliferation. Using the combined approach of blocking IFN-alpha beta Ab and the IFN receptor "knockout" mice, it was found here that the growth-inhibitory effects of LPS and TNF-alpha are due, to a significant extent, to endogenous IFN-alpha beta, whereas those of IFN-gamma and cAMP occur by a different mechanism. it is proposed that the type I IFN receptor (IFNAR 1) "knockout" mice may be useful in delineating some of the in vivo actions of CSF-1, LPS, TNF-alpha, and possibly other agents.
- Published
- 1996
13. Regulation of plasminogen activator inhibitor-1 levels in human monocytes.
- Author
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Hamilton JA, Whitty GA, Wojta J, Gallichio M, McGrath K, and Ianches G
- Subjects
- Cells, Cultured, Dexamethasone pharmacology, Enzyme-Linked Immunosorbent Assay, Gene Expression Regulation, Humans, In Vitro Techniques, Interleukin-4 pharmacology, Lipopolysaccharides pharmacology, Plasminogen Activator Inhibitor 1 biosynthesis, Prostaglandin-Endoperoxide Synthases, RNA, Messenger analysis, Transforming Growth Factors antagonists & inhibitors, Transforming Growth Factors pharmacology, Monocytes metabolism, Plasminogen Activator Inhibitor 1 blood
- Abstract
The regulation of PAI-1 synthesis by elutriation-purified human monocytes was studied in vitro and compared to that for PAI-2. PAI-1 formation, as measured by ELISA, was upregulated by TGF-beta (> or = 1 ng/ml) and surprisingly down-regulated by LPS (100 ng/ml), particularly in the presence of TGF-beta; LPS elevated PAI-2 levels (ELISA) while TGF-beta reduced its basal levels and those in LPS-treated cultures. Concomitant changes in mRNA expression occurred. The glucocorticoid dexamethasone (10(-7) M) elevated PAI-1 and acted in concert with TGF-beta in this regard at both the antigen and mRNA levels; interleukin-4 (IL-4) (250 pM) failed to mimic the steroid in its regulation of PAI-1 formation. Since monocyte/macrophage PA activity is likely to be important in tissue remodeling and cell migration at sites of inflammation and in fibrinolysis, it is proposed from these studies that PAI-1, as well as the usually considered PAI-2, may be involved in the negative control of PA activity in this cell type. The synthesis of each PAI appears to be independently regulated.
- Published
- 1993
- Full Text
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14. Effects of macrophage-colony stimulating factor on human monocytes: induction of expression of urokinase-type plasminogen activator, but not of secreted prostaglandin E2, interleukin-6, interleukin-1, or tumor necrosis factor-alpha.
- Author
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Hamilton JA, Whitty GA, Stanton H, and Meager A
- Subjects
- Cells, Cultured, Enzyme Induction, Granulocyte-Macrophage Colony-Stimulating Factor pharmacology, Humans, Interleukin-1 metabolism, Interleukin-6 metabolism, Interleukins metabolism, Monocytes metabolism, Dinoprostone metabolism, Macrophage Colony-Stimulating Factor pharmacology, Monocytes drug effects, Tumor Necrosis Factor-alpha metabolism, Urokinase-Type Plasminogen Activator biosynthesis
- Abstract
It is often assumed that macrophage-colony stimulating factor (M-CSF) or CSF-1, as well as granulocyte macrophage-CSF (GM-CSF), can induce inflammatory mediator production by monocytes/macrophages. We demonstrate with elutriation-purified human monocytes that, in contrast to lipopolysaccharide, recombinant human CSF-1 does not induce secretion of prostaglandin E2, interleukin-6 (IL-6), IL-1 beta, or tumor necrosis factor alpha, as measured by immunoassay; however, increased urokinase-type plasminogen activator (u-PA) activity in cell lysates and mRNA was observed. Similar results were obtained when the monocytes were treated with recombinant human GM-CSF. Such increased u-PA expression may contribute to the function of CSF-1 at sites of inflammation.
- Published
- 1993
- Full Text
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15. Interleukin-4 suppresses granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor levels in stimulated human monocytes.
- Author
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Hamilton JA, Whitty GA, Royston AK, Cebon J, and Layton JE
- Subjects
- Cells, Cultured, Dexamethasone pharmacology, Humans, Immune Tolerance immunology, Interferon-gamma immunology, Lipopolysaccharides immunology, Monocytes drug effects, Recombinant Proteins immunology, Granulocyte Colony-Stimulating Factor biosynthesis, Granulocyte-Macrophage Colony-Stimulating Factor biosynthesis, Interleukin-4 immunology, Monocytes immunology
- Abstract
Granulocyte colony-stimulating factor (G-CSF) was quantitated in the supernatants of lipopolysaccharide (LPS)-treated human monocytes by ELISA. Unlike previous reports, the lymphokines, interleukin-4 (IL-4) and interferon-gamma (IFN-gamma), were unable to induce the synthesis of G-CSF. Both IL-4 (> or = 10 pM) and the glucocorticoid, dexamethasone (10(-7) M), inhibited G-CSF production in the LPS-treated monocytes; in contrast, IFN-gamma had a weak potentiating effect on the LPS action. Changes in antigen expression were manifested at the level of messenger RNA (mRNA). Granulocyte-macrophage (GM)-CSF in the LPS-treated monocyte supernatants was also quantitated by ELISA but its levels were somewhat lower than for G-CSF; IL-4, dexamethasone and IFN-gamma had similar effects on GM-CSF levels as on G-CSF levels. The suppression of CSF production in the stimulated monocytes by IL-4 and glucocorticoid extends the list of monocyte cytokines whose levels can be down-regulated by these agents and suggests another potential anti-inflammatory and immunosuppressive function for IL-4.
- Published
- 1992
16. Regulation by interleukin-3 of human monocyte pro-inflammatory mediators. Similarities with granulocyte-macrophage colony-stimulating factor.
- Author
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Hart PH, Whitty GA, Burgess DR, and Hamilton JA
- Subjects
- Dose-Response Relationship, Immunologic, Humans, Interleukin-1 metabolism, Monocytes enzymology, Recombinant Proteins immunology, Tumor Necrosis Factor-alpha metabolism, Granulocyte-Macrophage Colony-Stimulating Factor immunology, Interleukin-3 immunology, Monocytes immunology, Plasminogen Activators metabolism, Urokinase-Type Plasminogen Activator metabolism
- Abstract
Urokinase-type plasminogen activator (u-PA), tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) activities were measured for highly purified human monocytes cultured for 18 hr with recombinant human interleukin-3 (IL-3). IL-3 alone stimulated monocyte u-PA activity, but not TNF-alpha or IL-1 activity. However, IL-3, together with interferon-gamma (IFN-gamma), stimulated the TNF-alpha, but not IL-1, activities of monocytes from several donors. In parallel cultures, granulocyte-macrophage colony-stimulating factor (GM-CSF) behaved similarly. IL-3, like GM-CSF, synergized weakly and sometimes irregularly with lipopolysaccharide (LPS) for increased TNF-alpha and IL-1 activities. Thus, IL-3 can selectively stimulate monocyte mediator production depending on the costimulus present; however, the stimulatory properties of IL-3 vary from those of IFN-gamma and IL-4. The similarities in activity between IL-3 and GM-CSF may be explained by a common or associated IL-3/GM-CSF receptor(s), as suggested by biochemical studies.
- Published
- 1990
17. Contrasting effects of interferon-gamma and interleukin-4 on the interleukin-6 activity of stimulated human monocytes.
- Author
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Cheung DL, Hart PH, Vitti GF, Whitty GA, and Hamilton JA
- Subjects
- Dexamethasone immunology, Drug Administration Schedule, Humans, Interleukin-4 administration & dosage, Interleukin-6 genetics, Lipopolysaccharides immunology, RNA, Messenger analysis, Recombinant Proteins immunology, Interferon-gamma immunology, Interleukin-4 immunology, Interleukin-6 immunology, Monocytes immunology
- Abstract
Stimulated human monocytes/macrophages are a source of interleukin-6 (IL-6), which is a likely mediator involved in immune and inflammatory reactions. The means to control production of IL-6 by these cells could therefore have therapeutic applications. We report here, for lipopolysaccharide (LPS)-stimulated human monocytes in vitro, that the lymphokine, interferon-gamma (IFN-gamma) (100 U/ml), enhanced the level of IL-6 activity, whereas another lymphokine, interleukin-4 (IL-4) (greater than or equal to 0.1 U/ml; greater than or equal to 1.2 x 10(-11) M), suppressed it. The effects of the two lymphokines were manifested at the level of mRNA. The action of the IL-4 was similar to that of the glucocorticoid, dexamethasone, but observed at a lower molar concentration. Such regulation of monocyte IL-6 activity is similar to that found previously for interleukin-1 (IL-1) and tumour necrosis factor-alpha (TNF-alpha) synthesis.
- Published
- 1990
18. Augmentation of glucocorticoid action on human monocytes by interleukin-4.
- Author
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Hart PH, Whitty GA, Burgess DR, Croatto M, and Hamilton JA
- Subjects
- Anti-Inflammatory Agents, Non-Steroidal pharmacology, Dinoprostone biosynthesis, Humans, Interleukin-1 biosynthesis, Macrophage Activation physiology, Prostaglandin-Endoperoxide Synthases metabolism, Tissue Plasminogen Activator physiology, Tumor Necrosis Factor-alpha biosynthesis, Glucocorticoids pharmacology, Interleukin-4 pharmacology, Monocytes drug effects
- Abstract
For their anti-inflammatory effects, glucocorticoids act, at least in part, by suppression of the production of interleukin-1 (IL-1), tumor necrosis factor alpha (TNF alpha) and prostaglandin E2 (PGE2) by activated monocytes/macrophages. Interleukin-4 (IL-4) also suppresses similar parameters of monocyte activation in vitro. However, contrasting effects of IL-4 and dexamethasone (Dex) on monocyte tissue-type plasminogen activator (t-PA) production suggest that these agents may operate by different pathways. We have now demonstrated that levels of IL-4 as low as 0.05-0.1 U/ml (0.6-1.2 x 10(-11)M) can augment the actions of Dex (5 x 10(-9)M) as an inhibitor of the production of monocyte pro-inflammatory mediators. These in vitro results suggest the possible supplementation of steroid therapy with low amounts of IL-4 (or an agonist) permitting the use of less steroid with concomitant reduction in steroid-associated side-effects. IL-4 can also suppress the increased release of IL-1 beta and TNF alpha by monocytes incubated with indomethacin, a non-steroidal anti-inflammatory drug.
- Published
- 1990
19. Potential antiinflammatory effects of interleukin 4: suppression of human monocyte tumor necrosis factor alpha, interleukin 1, and prostaglandin E2.
- Author
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Hart PH, Vitti GF, Burgess DR, Whitty GA, Piccoli DS, and Hamilton JA
- Subjects
- Cell Survival drug effects, Dexamethasone pharmacology, Gene Expression Regulation drug effects, Humans, In Vitro Techniques, Interleukin-4, Lipopolysaccharides pharmacology, Monocytes drug effects, Protein Biosynthesis, RNA, Messenger genetics, Recombinant Proteins pharmacology, Tumor Necrosis Factor-alpha genetics, Dinoprostone biosynthesis, Inflammation physiopathology, Interleukin-1 biosynthesis, Interleukins pharmacology, Monocytes physiology, Tumor Necrosis Factor-alpha biosynthesis
- Abstract
Stimulated human monocytes/macrophages are a source of mediators such as tumor necrosis factor alpha (TNF-alpha), interleukin 1 (IL-1), and prostaglandin E2 (PGE2), which can modulate inflammatory and immune reactions. Therefore, the ability to control the production of such mediators by monocytes/macrophages may have therapeutic benefits, and it has been proposed that glucocorticoids may act in this way. Purified human monocytes, when stimulated in vitro with lipopolysaccharide (LPS) or with LPS and gamma interferon (IFN-gamma), produce TNF-alpha, IL-1, and PGE2. Cotreatment of stimulated cells with the purified human lymphokine, interleukin 4 (IL-4 greater than or equal to 0.1-0.5 unit/ml; 12-60 pM) dramatically blocked the increased levels of these three mediators; for TNF-alpha and IL-1, the inhibition was manifest at the level of mRNA. Thus, IL-4 can suppress some parameters of monocyte activation and, as for B cells, have opposite effects to IFN-gamma. The effects of IL-4 on human monocytes are similar to those obtained with the glucocorticoid dexamethasone (0.1 microM).
- Published
- 1989
- Full Text
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20. Control by IFN-gamma and PGE2 of TNF alpha and IL-1 production by human monocytes.
- Author
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Hart PH, Whitty GA, Piccoli DS, and Hamilton JA
- Subjects
- Cells, Cultured, Dinoprostone metabolism, Humans, Indomethacin pharmacology, Lipopolysaccharides pharmacology, Monocytes metabolism, Prostaglandin-Endoperoxide Synthases physiology, Recombinant Proteins, Dinoprostone pharmacology, Interferon-gamma pharmacology, Interleukin-1 biosynthesis, Monocytes drug effects, Tumor Necrosis Factor-alpha biosynthesis
- Abstract
There have been suggestions that the production of pro-inflammatory mediators by human monocytes in response to interferon-gamma (IFN-gamma) may be controlled by changes in prostaglandins. Therefore we investigated tumour necrosis factor alpha (TNF alpha) and interleukin-1 (IL-1) activities and prostaglandin E2 (PGE2) levels in the supernatants of highly purified human monocytes cultured for 18 hr with recombinant human IFN-gamma. IFN-gamma (100 U/ml) did not stimulate monocytes isolated by counter-current centrifugal elutriation for detectable TNF alpha or IL-1 activities, or PGE2 production. However, IFN-gamma synergistically enhanced lipopolysaccharide (LPS)-induced TNF alpha and IL-1 activities. In contrast, there was no consistent change in PGE2 levels upon addition of IFN-gamma to LPS-treated monocyte cultures. The TNF alpha and IL-1 activities induced by LPS and by LPS with IFN-gamma were reduced by PGE2, and stimulated by indomethacin. As reported previously for IL-1 activities, the regulation by cyclo-oxygenase products of TNF alpha activities reflected predominantly a control of the production of immunoreactive TNF alpha, rather than the measurement of TNF alpha bio-activity. However, the addition of indomethacin or PGE2 to monocyte cultures did not change the extent of IFN-gamma synergy with LPS for increased TNF alpha and IL-1 activities. The results of this study suggest that, despite control by cyclo-oxygenase products of TNF alpha and IL-1 production in human monocytes, IFN-gamma may enhance TNF alpha and IL-1 activities independently of this regulatory mechanism. These findings are contrary to those suggested for the regulation by prostanoids of IL-1 production by murine macrophages.
- Published
- 1989
21. Synergistic activation of human monocytes by granulocyte-macrophage colony-stimulating factor and IFN-gamma. Increased TNF-alpha but not IL-1 activity.
- Author
-
Hart PH, Whitty GA, Piccoli DS, and Hamilton JA
- Subjects
- Dinoprostone, Drug Synergism, Granulocyte-Macrophage Colony-Stimulating Factor, Humans, Monocytes cytology, Monocytes immunology, Prostaglandins E biosynthesis, Colony-Stimulating Factors pharmacology, Growth Substances pharmacology, Interferon-gamma pharmacology, Interleukin-1 biosynthesis, Macrophage Activation drug effects, Monocytes metabolism, Tumor Necrosis Factor-alpha biosynthesis
- Abstract
TNF-alpha and IL-1 activities and PGE2 levels were investigated in the supernatants of highly purified human monocytes cultured for 18 h with recombinant human granulocyte-macrophage CSF (GM-CSF). GM-CSF alone did not stimulate IL-1 or TNF-alpha activities or the production of PGE2. GM-CSF with IFN-gamma, but not with LPS, consistently activated the monocytes for TNF-alpha activity. In contrast, for increased IL-1 activity, GM-CSF synergized weakly and irregularly with LPS, but not at all with IFN-gamma. For the third monocyte product investigated, GM-CSF was a weak and inconsistent inducer of PGE2 and only in the co-presence of IFN-gamma. Thus, GM-CSF can elicit different responses in human monocytes depending both on the co-stimulus as well as the monocyte product being investigated.
- Published
- 1988
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