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Complex network of cytokines activating murine microglial cell activity against Acanthamoeba castellani
Nunzia Benedetto1, Claude Auriault
1Institute of Microbiology, Faculty of Medicine and Surgery, Second University of the Studies of Naples, Larghetto Sant' Aniello a Caponapoli 2, 80138 Naples, Italy.
Abstract:
In the central nervous system, cytokine-primed microglia play a pivotal role in host defence against Acanthamoeba castellani infections. In this study, the effect of rIL-1beta, rIL-6 or rTNF-alpha, combined or not with rIFN-gamma, on A. castellani infection of murine microglia was examined. Priming of microglial cells with either rIL-1beta or rIL-6, in the presence or absence of rIFN-gamma, triggered amebastatic activity, while the treatment of microglia with rTNF-alpha plus rIFN-gamma additively triggered, in a dose-dependent fashion, amebicidal activity. Inasmuch as NGMA affected cytokine-triggered anti-parasitic activity during the priming process, the NO-dependent pathway itself appears not to be directly involved in the anti-amebic capacities. These data suggest that the proinflammatory cytokines IL-1beta, IL-6 or TNF-alpha could trigger anti-microbial activity against A. castellani infection in the brain.
Insights
Pro-inflammatory cytokines like IL-1beta, IL-6, and TNF-alpha prime microglia for defense against Acanthamoeba castellani brain infections. These cytokines induce anti-parasitic activity, crucial for host defense.
Area of Science:
- Neuroimmunology
- Infectious Diseases
- Cell Biology
Background:
- Microglia are key immune cells in the central nervous system.
- Acanthamoeba castellani is an opportunistic pathogen causing brain infections.
- Cytokines modulate microglial immune responses.
Purpose of the Study:
- To investigate the effect of specific cytokines on microglial defense against Acanthamoeba castellani.
- To determine if cytokines induce amebastatic or amebicidal activity.
- To explore the role of nitric oxide (NO) in cytokine-mediated anti-parasitic activity.
Main Methods:
- Murine microglia were primed with recombinant cytokines: IL-1beta, IL-6, TNF-alpha, and IFN-gamma.
- Primed microglia were exposed to Acanthamoeba castellani.
- Amebicidal and amebastatic activities were assessed.
- The effect of NGMA (a NO inhibitor) on cytokine-induced activity was examined.
Main Results:
- Priming with IL-1beta or IL-6 (with or without IFN-gamma) induced amebastatic activity.
- Treatment with TNF-alpha plus IFN-gamma triggered dose-dependent amebicidal activity.
- The NO-dependent pathway was not directly involved in the anti-parasitic activity.
Conclusions:
- Pro-inflammatory cytokines IL-1beta, IL-6, and TNF-alpha can activate microglial anti-parasitic functions.
- These cytokines may represent a therapeutic strategy against Acanthamoeba infections in the brain.
- Cytokine-induced microglial defense mechanisms are complex and not solely NO-dependent.