Priming Effects Of Granulocyte-macrophage Colony-stimulating Factor Research Articles

Lack of effect of granulocyte-macrophage and granulocyte colony- stimulating factors on cultured human endothelial cells [see comments

The hematopoietic growth factors, granulocyte-macrophage colony- stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF), enhance the effector functions of mature myeloid cells, including the interaction with vascular endothelium. We examined the direct effect of recombinant human GM-CSF (rhGM-CSF) and recombinant human G-CSF (rhG-CSF) on the growth and function of cultured human umbilical vein endothelial cells (HUVEC). Endothelial cell growth supplement (ECGS) increased the proliferation of passaged and primary cells by 305% +/- 45% (mean +/- SEM, n = 5, P less than .01) over control cells at 4 days; GM-CSF and G-CSF had no effect. Endothelial cell procoagulant activity was increased after 4-hour incubation with recombinant interleukin-1 beta (IL-1 beta) 10 U/mL and recombinant tumor necrosis factor (TNF) 10 U/mL to 1,721% +/- 376% (n = 7, P less than .005) and 247% +/- 71% (n = 4) of control levels, respectively. gamma-Interferon (gamma-IFN) 50 U/mL had no direct effect of its own but was able to prime the response to IL-1 beta. There was no direct or priming effect of GM-CSF (1 ng to 1 microgram/mL) on the expression of procoagulant activity in endothelial cells. GM-CSF and G-CSF (1 ng/mL to 1 microgram/mL) had no effect on the expression of either tissue plasminogen activator (tPA) or plasminogen activator inhibitor-1 (PAI- 1) by endothelial cells. The secretion of tPA by endothelial cells was increased, however, after 24-hour incubation with thrombin 4 U/mL (314% +/- 72% of control levels, n = 5, P less than .025). The production of PAI-1 was increased by TNF 200 U/mL (241% +/- 44% of control, n = 3, P less than .005), thrombin 4 U/mL (180% +/- 12% of control, n = 5, P less than .0005) and IL-1 beta 10 U/mL (275% +/- 44% of controls, n = 5, P less than .0005). In four experiments, endothelial cells showed no specific binding of 125I-GM-CSF, whereas peripheral blood (PB) neutrophils demonstrated the presence of 802 +/- 78 high-affinity receptors for GM-CSF. Thus, we found no effect of rhGM-CSF or rhG-CSF on the proliferation activities by these cells. These findings are in accordance with the lack of demonstrable receptors for GM-CSF on cultured HUVEC.

Lack of Effect of Granulocyte-Macrophage and Granulocyte Colony-Stimulating Factors on Cultured Human Endothelial Cells

AbstractThe hematopoietic growth factors, granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF), enhance the effector functions of mature myeloid cells, including the interaction with vascular endothelium. We examined the direct effect of recombinant human GM-CSF (rhGM-CSF) and recombinant human G-CSF (rhG-CSF) on the growth and function of cultured human umbilical vein endothelial cells (HUVEC). Endothelial cell growth supplement (ECGS) increased the proliferation of passaged and primary cells by 305% ± 45% (mean ± SEM, n = 5, P < .01) over control cells at 4 days; GM-CSF and G-CSF had no effect. Endothelial cell procoagulant activity was increased after 4-hour incubation with recombinant interleukin-1 β (IL-1β) 10 U/mL and recombinant tumor necrosis factor (TNF) 10 U/mL to 1,721% ± 376% (n = 7, P < .005) and 247% ± 71% (n = 4) of control levels, respectively. γ-Interferon (γ-IFN) 50 U/mL had no direct effect of its own but was able to prime the response to IL-1β. There was no direct or priming effect of GM-CSF (1 ng to 1 μg/mL) on the expression of procoagulant activity in endothelial cells. GM-CSF and G-CSF (1 ng/mL to 1 μg/mL) had no effect on the expression of either tissue plasminogen activator (tPA) or plasminogen activator inhibitor-1 (PAI-1) by endothelial cells. The secretion of tPA by endothelial cells was increased, however, after 24-hour incubation with thrombin 4 U/mL (314% ± 72% of control levels, n = 5, P < .025). The production of PAI-1 was increased by TNF 200 U/mL (241% ± 44% of control, n = 3, P < .005), thrombin 4 U/mL (180% ± 12% of control, n = 5,P < .0005) and IL-1 β 10 U/mL (275% ± 44% of controls, n = 5, P < .0005). In four experiments, endothelial cells showed no specific binding of 125I-GM-CSF, whereas peripheral blood (PB) neutrophils demonstrated the presence of 802 ± 78 high-affinity receptors for GM-CSF. Thus, we found no effect of rhGM-CSF or rhG-CSF on the proliferation of HUVEC or the expression of procoagulant and fibrinolytic activities by these cells. These findings are in accordance with the lack of demonstrable receptors for GM-CSF on cultured HUVEC.

Characterization of the priming effects of human granulocyte-macrophage colony-stimulating factor on human neutrophil leukotriene synthesis

Human granulocyte-macrophage colony-stimulating factor (Gm-CSF) is an in vitro and in vivo stimulator of human bone marrow myelomonocytic precursor cells and mature granulocyte and macrophage effector cells. We have compared the effect of GM-CSF on the synthesis of 5-lipoxygenase products induced by the chemotactic peptide fMet-Leu-Phe and the calcium ionophore A23187 in human neutrophils. Although Gm-CSF alone did not stimulate detectable synthesis of products of the 5-lipoxygenase pathway, pre-incubation of neutrophils with 200 pM GM-CSF for 1 hour at 23°C enhanced synthesis of leukotriene B 4, its all-trans isomers and Ω-oxidation products, and 5-hydroxyeicosatetraenoic acid in response to both the calcium ionophore A23187 (1.5 μm), and the chemotactic peptide fMet-Leu-Phe (0.1 μM). This priming effect of Gm-CSF was maximal after a 60 min incubation at 23°C, or after a 30 min pre-incubation at 37°C. The effect of GM-CSF was maximal using a concentration of 1 nM. Enhancement of the leukotriene synthesis stimulated by A23187 was only observed when the cells were stimulated by the ionophore for periods of 3 minutes or less. In contrast, the enhancing effect of GM-CSF was still apparent when cells were exposed to fMet-Leu-Phe for as long as 15 minutes. Furthermore, the enhancing effect of GM-CSF was ablated when neutrophils were stimulated with A23187 and exogenous arachidonic acid. However, co-addition and exogenous arachidonic acid with fMet-Leu-Phe did not entirely mask the effect of GM-CSF. Possible mechanisms of action of GM-CSF are discussed.