Involvement of both protein kinase C and G proteins in superoxide production after IgE triggering in guinea pig eosinophils

ABSTRACTTo study the function and mechanism of eosinophils via the low affinity IgE receptor (FceRII), we examined the production of 02 metabolites by measuring the luminol-dependent chemiluminescence (LDCL) response and the generation of cysteinyl leukotrienes. Eosinophils obtained from guinea pig peritoneal fluid sensitized with horse serum were purified. Luminol-dependent chemiluminescence was induced by stimulation with monoclonal anti-CD23 antibody, but not by mouse serum (controls). The mean (±SEM) value of LDCL was 20.6±1.3X103 c.p.m. This reaction consisted of an initial rapid phase and a propagation phase and ended within lOmin. Guinea pig eosinophils were histochemically stained with monoclonal anti-CD23 antibody. The major product generated in the LDCL response was superoxide, as determined by the measurement of superoxide by cytochrome c reduction and the complete inhibitory effect of superoxide dismutase on the LDCL response. Pretreatment with either pertussis toxin or cholera toxin inhibited the LDCL reaction. Depletion of bivalent ions by EDTA inhibited this response and the protein kinase C inhibitor D-sphingosin inhibited both 1-oleoyl-2-acetyl-glycerol-induced and FcϵRII-mediated LDCL. These findings suggest that the NADPH-protein kinase C pathway may be involved in the FceRII-mediated LDCL response in guinea pig eosinophils

Effects of phosphodiesterase inhibitors on secretions of human monokines

ABSTRACTThe purpose of this study was to evaluate the effect of newly developed selective phosphodiesterase (PDE) inhibitors, KF19514 (type l/IV) and cilostazol (type III), and theophylline on the secretions of tumor necrosis factor a (TNFα) and interleukin-1β (IL-1 β) from human peripheral monocytes stimulated by lipopolysaccha- ride (LPS). Human blood monocytes were incubated with LPS in the absence or presence of KF19514, cilostazol or theophylline. TNFα and IL-1in the cell- free supernatants were measured with enzyme-linked immunosorbent assay. KF19514 showed significant inhibition on the release of TNFα (% inhibition ± SEM was 82.8 ± 7.4% at 1 nmol/L) and IL-1 β (34.4 ± 7.5% at 10 (μmol/L). In addition, KF19514 inhibited the expression of TNFa mRNA. Cilostazol inhibited the release of TNFa significantly (60.2 ± 8.9% at 30 μmol/L) but not IL-1 β. Theophylline inhibited slightly but significantly the release of TNFa at a therapeutic concentration (1 7.4 ± 5.1% at 100 μmol/L). These results suggest that theophylline may not only have a bronchodilating action but also an anti-inflammatory property in the treatment of bronchial asthma, and that KF19514 may have an anti-inflammatory action on at least the transcriptional level

Coronary angioplasty ameliorates hypoperfusion-induced endothelial dysfunction in patients with stable angina pectoris

Objectives.This study sought to investigate the effect of coronary angioplasty on chronic hypoperfusion-induced endothelial dysfunction in patients with coronary heart disease.Background.The endothelium is an important component for organ flow regulation. Ischemia with or without reperfusion is known to cause endothelial dysfunction. We tested the hypothesis that chronic hypoperfusion impairs endothelial function in the angiographically normal coronary artery segment distal to stenosis and that the impairment by chronic hypoperfusion is reduced by coronary angioplasty.Methods.In 13 patients with stable angina pectoris, substance P (10, 30 and 100 pmol) and nitroglycerin (200 μg) were sequentially infused into the coronary artery in a cumulative manner on the day after coronary angioplasty. In 10 of these patients, vascular responses to these agents were again investigated 3 months after angioplasty. Changes in vascular diameter were evaluated in vessels located proximal and distal to the target lesion, both of which were angiographically normal, by performing computer-assisted quantitative coronary angiography. In five patients, the transstenotic pressure gradient was also measured with a pressure sensor-mounted guide wire before angioplasty.Results.On the day after angioplasty, the magnitude of dilation by substance P in distal segments was significantly less than that in proximal segments and inversely correlated with the transstenotic pressure gradient (p < 0.05) and lesion stenosis (p < 0.05). There was no difference in nitroglycerin-induced vasodilation between the two vessel segment groups. Three months later, the impaired response to substance P in the distal segment was restored to normal.Conclusions.We conclude that chronic hypoperfusion impairs endothelium-dependent dilation of coronary artery distal to critical stenosis in patients with ischemic heart disease and that coronary angioplasty ameliorates the endothelial dysfunction within 3 months

Prevention of Tracheal High-Dose Tolerance Induction by Granulocyte-Macrophage Colony Stimulating Factor- Dependent Restoration of Antigen-Presenting Cell Function

The intrusion of airborne allergens into airways elicits eosinophilic inflammation, as represented by bronchial asthma. It has been shown that excessive amounts of allergen in murine trachea lead to an unexpected evasion of deleterious eosinophilic inflammation by inducing T cell tolerance. In the present study, the mechanisms of tracheal high-dose tolerance are examined with regard to accessory cell functions and the effects of pro-inflammatory cytokines on tolerance. Antigen-induced tracheal eosinophilia was suppressed on instillation of high doses of antigen into the trachea, while concurrent instillation of granulocyte-macrophage colony stimulating factor (GM-CSF) with the antigen restored the diminished responses. The restoration of eosinophilic infiltration by GM-CSF occurred in parallel with an increase in interleukin (IL)-4 production by CD4+ T cells from the mediastinal lymph nodes. This was found to reflect the empowerment of antigen-presenting cells by GM-CSF, because the impaired ability of Ia+ cells from the tolerant mice to stimulate IL-4-producing T cells is restored by GM-CSF administration. The prevention of tolerance by up-regulating accessory cell functions is a feature unique to GM-CSF, because another pro-inflammatory cytokine, IL-iβ, failed to empower antigen-presenting cells. Thus, besides the induction of transforming growth factor-β-secreting CD4+ T cells, high-dose tolerance in the trachea includes an impairment of the accessory cell functions that support IL-4 production from T cells, which was reversed by GM-CSF. This report is the first demonstration that GM-CSF breaks the T cell tolerance of IL-4-producing T helper cells