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The effect of gliotoxin upon macrophage function
Abstract:
Gliotoxin, a metabolite of the fungus Aspergillus fumigatus, inhibited phagocytosis of particulate matter by rodent macrophages. In addition, adherence to plastic surfaces by peritoneal and alveolar rodent macrophages, human peripheral blood monocytes, mouse secondary fibroblasts and L929 cells was differentially inhibited by gliotoxin. Electron microscopy which confirmed the inhibition by gliotoxin of phagocytosis of carbon particles by rodent macrophages also revealed gliotoxin-induced morphological alterations. Gliotoxin selectively affected glucose metabolism and macromolecular synthesis of rodent-derived cells and inhibited the basal rate of H2O2 production by human polymorphonuclear neutrophils; bactericidal activity of resident peritoneal macrophages was also abrogated. These gliotoxin-induced changes in cell function and metabolism occurred at concentrations well below generalized toxic levels.
Insights
Gliotoxin from Aspergillus fumigatus impairs macrophage phagocytosis and cell adherence. This fungal metabolite also alters cell morphology and function at non-toxic levels.
Area of Science:
- Immunology
- Mycology
- Cell Biology
Background:
- Gliotoxin is a mycotoxin produced by Aspergillus fumigatus.
- Mycotoxins can impact host immune responses.
- Understanding gliotoxin's cellular effects is crucial for assessing its biological significance.
Purpose of the Study:
- To investigate the effects of gliotoxin on cellular functions.
- To determine gliotoxin's impact on phagocytosis and cell adherence.
- To explore gliotoxin's influence on cellular metabolism and morphology.
Main Methods:
- Utilized rodent macrophages, human monocytes, fibroblasts, and L929 cells.
- Assessed phagocytosis using carbon particles.
- Employed electron microscopy for morphological analysis.
- Measured glucose metabolism, macromolecular synthesis, and hydrogen peroxide production.
Main Results:
- Gliotoxin inhibited phagocytosis and adherence in various cell types.
- Electron microscopy revealed gliotoxin-induced morphological changes.
- Selective inhibition of glucose metabolism and macromolecular synthesis in rodent cells.
- Inhibition of H2O2 production in human neutrophils and abrogated bactericidal activity in macrophages.
Conclusions:
- Gliotoxin exhibits potent immunomodulatory effects at sub-toxic concentrations.
- The mycotoxin disrupts critical cellular functions including phagocytosis and metabolism.
- Gliotoxin's diverse cellular impacts warrant further investigation into its role in fungal pathogenesis.