Related Experiment Video
Updated: Mar 15, 2026
Isolation of Cortical Microglia with Preserved Immunophenotype and Functionality From Murine Neonates
Published on: January 30, 2014
Mechanisms Underlying Interferon-γ-Induced Priming of Microglial Reactive Oxygen Species Production
Nicholas G Spencer1, Tom Schilling1, Francesc Miralles2,3
1Infection and Immunity Research Institute, St. George's University of London, London, United Kingdom.
Abstract:
Microglial priming and enhanced reactivity to secondary insults cause substantial neuronal damage and are hallmarks of brain aging, traumatic brain injury and neurodegenerative diseases. It is, thus, of particular interest to identify mechanisms involved in microglial priming. Here, we demonstrate that priming of microglia with interferon-γ (IFN γ) substantially enhanced production of reactive oxygen species (ROS) following stimulation of microglia with ATP. Priming of microglial ROS production was substantially reduced by inhibition of p38 MAPK activity with SB203580, by increases in intracellular glutathione levels with N-Acetyl-L-cysteine, by blockade of NADPH oxidase subunit NOX2 activity with gp91ds-tat or by inhibition of nitric oxide production with L-NAME. Together, our data indicate that priming of microglial ROS production involves reduction of intracellular glutathione levels, upregulation of NADPH oxidase subunit NOX2 and increases in nitric oxide production, and suggest that these simultaneously occurring processes result in enhanced production of neurotoxic peroxynitrite. Furthermore, IFNγ-induced priming of microglial ROS production was reduced upon blockade of Kir2.1 inward rectifier K+ channels with ML133. Inhibitory effects of ML133 on microglial priming were mediated via regulation of intracellular glutathione levels and nitric oxide production. These data suggest that microglial Kir2.1 channels may represent novel therapeutic targets to inhibit excessive ROS production by primed microglia in brain pathology.
Insights
Interferon-γ primes microglia to produce more reactive oxygen species (ROS). Blocking Kir2.1 channels reduces this priming, offering a potential therapeutic target for brain diseases.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Microglial priming enhances reactivity to secondary insults, contributing to neuronal damage in aging, TBI, and neurodegenerative diseases.
- Understanding microglial priming mechanisms is crucial for developing therapeutic strategies.
Purpose of the Study:
- To investigate the mechanisms underlying interferon-γ (IFNγ)-induced microglial priming.
- To identify potential therapeutic targets for modulating excessive microglial reactivity.
Main Methods:
- Priming microglia with IFNγ and stimulating with ATP to measure reactive oxygen species (ROS) production.
- Utilizing inhibitors for p38 MAPK (SB203580), NADPH oxidase (gp91ds-tat), nitric oxide synthase (L-NAME), and Kir2.1 channels (ML133).
- Assessing the role of intracellular glutathione levels and nitric oxide production in microglial priming.
Main Results:
- IFNγ priming significantly increased ATP-stimulated ROS production in microglia.
- Inhibition of p38 MAPK, NOX2, and nitric oxide synthase, along with increased glutathione, reduced primed ROS production.
- Blockade of Kir2.1 inward rectifier K+ channels with ML133 attenuated IFNγ-induced microglial priming.
- ML133's effects were linked to the regulation of intracellular glutathione levels and nitric oxide production.
Conclusions:
- Microglial priming involves reduced glutathione, upregulated NOX2, and increased nitric oxide, leading to enhanced neurotoxic peroxynitrite production.
- Microglial Kir2.1 channels are implicated in IFNγ-induced priming and represent a potential therapeutic target to mitigate excessive ROS production in brain pathology.
