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Updated: Jun 17, 2026
Depletion and Reconstitution of Macrophages in Mice
Published on: August 1, 2012
[Inhibitory effect of dexamethasone on myeloid differentiation factor 88 and tumor necrosis factor-alpha expressions
Wen-jie Zhao1, Li-yan Xi, Li Ma
1Department of Dermatology, Second Affiliated Hospital, Sun Yat-sen University, Guangzhou 510120, China. zhaowenjie1972@sohu.com
Objective:
To study the inhibitory effect of dexamethasone (DEX) on myeloid differentiation factor 88 (MyD88) and tumor necrosis factor-alpha (TNF-alpha) expression in mouse peritoneal macrophages in innate immune response to Penicillium marneffei (PM).
Methods:
Mouse peritoneal macrophages were cultured in the presence of heat-inactivated yeast-phase PM with or without DEX, and the protein and mRNA expressions of MyD88 in the macrophages were detected using Western blotting and real-time PCR, respectively. TNF-alpha in the cell culture supernatant was measured with enzyme-linked immunosorbent assay.
Results:
DEX suppressed TNF-alpha production by the macrophages co-cultured with PM. The expressions of MyD88 were up-regulated by PM stimulation, whose effect was inhibited by the application of DEX.
Conclusion:
The inhibitory effect of DEX on PM-induced proinflammatory responses of the macrophage is directly associated with the inhibition of MyD88 expression.
Insights
Dexamethasone (DEX) inhibits the innate immune response of mouse macrophages to Penicillium marneffei (PM) by suppressing myeloid differentiation factor 88 (MyD88) and tumor necrosis factor-alpha (TNF-alpha) expression.
Area of Science:
- Immunology
- Microbiology
- Pharmacology
Context:
- The innate immune system is crucial for host defense against fungal infections.
- Penicillium marneffei (PM) is an opportunistic fungal pathogen causing significant morbidity and mortality.
- Glucocorticoids like dexamethasone (DEX) are potent anti-inflammatory agents with complex immunomodulatory effects.
Purpose:
- To investigate the effect of dexamethasone (DEX) on myeloid differentiation factor 88 (MyD88) and tumor necrosis factor-alpha (TNF-alpha) expression in mouse peritoneal macrophages during innate immune response to Penicillium marneffei (PM).
Summary:
- Mouse peritoneal macrophages were stimulated with heat-inactivated PM in the presence or absence of DEX.
- Western blotting and real-time PCR were used to assess MyD88 protein and mRNA expression.
- Enzyme-linked immunosorbent assay measured TNF-alpha levels in the supernatant.
- Results showed DEX suppressed PM-induced TNF-alpha production.
- DEX also inhibited the upregulation of MyD88 expression induced by PM stimulation.
Impact:
- Dexamethasone's anti-inflammatory effect on PM-induced macrophage responses is linked to the inhibition of MyD88 expression.
- This finding provides insights into the molecular mechanisms underlying glucocorticoid action in fungal infections.
- Understanding these pathways could inform therapeutic strategies for managing PM infections.
