Search results for "Zymosan"
showing 10 items of 58 documents
Participation of Heme Oxygenase-1 in a Model of Acute Inflammation
2003
In this study, the role of heme oxygenase-1 (HO-1) in the inflammatory response elicited by zymosan in the mouse air pouch model has been examined. This response is characterized by a time-dependent increase in HO-1 expression in the leukocytes migrating into the exudates. At 24–48 h maximal HO-1 expression was accompanied by reduced cyclooxygenase-2 (COX-2) and nitric oxide synthase-2 (NOS-2) expression as well as low levels of inflammatory mediators. Hemin administration into the air pouch caused an elevation of HO-1 protein and bilirubin levels induced by zymosan with inhibition of COX-2 expression. In mouse peritoneal macrophages from hemin-injected mice, we also observed an increased …
PRR signaling during in vitro macrophage differentiation from progenitors modulates their subsequent response to inflammatory stimuli.
2017
Toll-like receptor (TLR) agonists drive hematopoietic stem and progenitor cells (HSPCs) to differentiate along the myeloid lineage in vitro and also in vivo following infection. In this study, we used an in vitro model of HSPC differentiation to investigate the functional consequences (cytokine production) that exposing HSPCs to various pathogen-associated molecular patterns (PAMPs) and Candida albicans cells have on the subsequently derived macrophages. Mouse HSPCs (Lin- cells) were cultured with GM-CSF to induce macrophage differentiation in the presence or absence of the following pattern recognition receptor (PRR) agonists: Pam3CSK4 (TLR2 ligand), LPS (TLR4 ligand), depleted zymosan (wh…
Control of the production of oxygen intermediates of human polymorphonuclear leukocytes and monocytes by beta-adrenergic receptors.
1983
The control by beta-adrenergic receptors of the production of oxygen radicals by zymosan-stimulated human polymorphonuclear leukocytes (PMN) and monocytes (M phi) was studied in vitro by means of chemiluminescence. In addition we asked whether PMN and M phi exhibit differential sensitivity to beta-adrenergic stimulation. For beta-adrenergic stimulation we applied fenoterol ranging from 10(-5) to 10(-9) M x 2.7. We found a dose-dependent suppression of the production of oxygen radicals, the ID50 being approximately 10(-6) M both for PMN and M phi. By assessment of lactic dehydrogenase release a cytotoxic effect of the drug could be ruled out. When incubated together with the beta-adrenergic …
β-Adrenoceptor stimulation up-regulates phosphodiesterase 4 activity and reduces prostaglandin E 2 -inhibitory effects in human neutrophils
2000
Human neutrophils were treated for 4 h with a combination of salbutamol (1 µM), a β2-adrenoceptor agonist, and rolipram (30 µM), a selective phosphodiesterase 4 inhibitor, to investigate whether this treatment produces up-regulation of phosphodiesterase activity with functional consequences. Anion-exchange chromatography coupled with the use of selective activators and inhibitors demonstrated that a phosphodiesterase activity with characteristics of the isoenzyme type 4 was increased in drug-treated cells. Kinetic analysis showed a ~1.5-fold increase in V max without alteration of K m values. The augmented phosphodiesterase activity in drug-treated cells was abolished by actinomycin D. Cycl…
Increased respiratory burst activity of monocytes and polymorphonuclear leukocytes in psoriasis.
1982
SUMMARY We studied the respiratory burst activity of peripheral blood monocytes and polymorphonu clear leukocytes (PMN) in eleven patients with psoriasis and eleven healthy controls, using zymosan particles to activate the phagocytes in vitro. The activation of the phagocytes was measured in a luminol-enhanced chemiluminescence (CL) assay. We found a significantly higher respiratory burst activity of both monocytes and PMN in patients with psoriasis compared with the control subjects. The percentages of monocytes in psoriatics did not differ from those of the controls. The higher amount of zymosan-induced CL activity generated in the patient group was unrelated to the age of the individual.…
Oxygen Radical Production by Alveolar Inflammatory Cells in Idiopathic Pulmonary Fibrosis
1990
Idiopathic pulmonary fibrosis (IPF) is a chronic inflammatory interstitial lung disease characterized by the accumulation of alveolar macrophages (AMs) and neutrophils in the lower respiratory tract, parenchymal cell injury, and fibrosis of the alveolar structure. Reactive oxygen intermediates (ROI) are claimed to be a major cause of tissue damage in IPF; however, the source of ROI has not been unequivocally identified. AMs, as well as neutrophils, are capable of releasing these agents. The contributions of these possible sources are not known. To address this question, we evaluated the spontaneous and stimulated (PMA or zymosan) ROI release of total bronchoalveolar cells and isolated AMs i…
Stimulus-Dependent Increased Generation of Oxygen Intermediates in Monocytes and Polymorphonuclear Leukocytes in Psoriasis
1985
Based on recent findings indicating increased respiratory burst activity of monocytes (M phi) and polymorphonuclear leukocytes (PMN) in psoriasis upon stimulation with zymosan particles, we examined the question of whether incubation with various stimuli always results in augmented oxidative metabolism in psoriatic phagocytes. We compared M phi and PMN isolated from the peripheral blood of 12 patients with psoriasis and 12 control individuals. We measured the generation of oxygen intermediates of resting and stimulated M phi and PMN by luminol-enhanced chemiluminescence. The stimulants applied were: (1) aggregated immunoglobulin (aggIg), (2) zymosan, (3) zymosan opsonized with autologous se…
4-dimethylamino-3′,4′-dimethoxychalcone downregulates iNOS expression and exerts anti-inflammatory effects
2001
Abstract Reactive oxygen and nitrogen species contribute to the pathophysiology of inflammatory conditions. We have studied the effects of a novel superoxide scavenger, 4-dimethylamino-3′,4′-dimethoxychalcone (CH11) in macrophages and in vivo. CH11 has been shown to inhibit the chemiluminescence induced by zymosan in mouse peritoneal macrophages and the cytotoxic effects of superoxide. In the same cells, the modulation by superoxide of nitric oxide (NO) production in response to zymosan was investigated. CH11 was more effective than the membrane-permeable scavenger Tiron for inhibition of inducible nitric oxide synthase (iNOS) protein expression and nitrite production. We have shown that CH…
Functionally active complement proteins C6 and C7 detected in C6- and C7-deficient individuals
1991
SUMMARYTwo sensitive sandwich ELISAs based on monoclonal antibodies directed to native C6 and C7 allowed the detection and quantitation of these complement proteins in 20 out of 37 serum samples from individuals who had previously been classified as deficient in these proteins as assessed by immunochemical and/or functional assays. Furthermore, serum from four C6-deficient and one combined C6-/C7-deficient individual showed an increase in the terminal complement complex (TCC) and a decrease in native C6 and C7 after complement activation as assayed by specific ELISAs. Despite their (incomplete) deficiencies, these individuals therefore possess functionally active terminal complement protein…
TLR2 and Dectin-1 Signaling in Mouse Hematopoietic Stem and Progenitor Cells Impacts the Ability of the Antigen Presenting Cells They Produce to Acti…
2020
Microbial recognition by pattern recognition receptors (PRRs) expressed on hematopoietic stem and progenitor cells (HSPCs) not only activates myelopoiesis but also programs the function of the monocytes and macrophages they produce. For instance, changes in HSPC programming modify the ability of macrophages derived from them to produce inflammatory cytokines. While HSPCs exposed to a TLR2 agonist give rise to tolerized macrophages (lower proinflammatory cytokine production), HSPCs treated with Dectin-1 ligands produce trained macrophages (higher proinflammatory cytokine production). However, nothing is known about the impact of HSPC exposure to microbes on the function of antigen presenting…