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Updated: Aug 17, 2026
Isolation of Cortical Microglia with Preserved Immunophenotype and Functionality From Murine Neonates
Published on: January 30, 2014
Microglial EP2 is critical to neurotoxicity from activated cerebral innate immunity
Feng-Shiun Shie1, Kathleen S Montine, Richard M Breyer
1Department of Pathology, University of Washington, Seattle, Washington, USA.
Abstract:
Prostaglandin (PG) E(2) acts via four functionally antagonistic E-prostanoid (EP) receptors that are expressed on multiple cell types in the nervous system; these are designated EP1-4. We showed previously that EP2 null mice are protected from CD14-dependent neuronal damage in vivo following intracerebroventricular (ICV) injection of lipopolysaccharide (LPS). Clear interpretation of this neuroprotective outcome is limited because EP2 is expressed on glia and neurons. We tested the hypothesis that microglial EP2 is required for paracrine neurotoxicity following activation of innate immunity, using primary murine microglia and neuron co-cultures. We demonstrated that microglial EP2 was necessary for lipopolysaccharide (LPS)-activated microglia-mediated neurotoxicity, as well as induction of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2). Genetic deletion of microglial iNOS, pharmacological suppression of COX-2 activity, or addition of exogenous superoxide dismutase (SOD) and catalase in the presence of EP2 also abolished neurotoxicity. This loss of paracrine neurotoxicity by EP2(-/-) microglia occurred in the absence of reduced cytokine levels. We conclude that microglial EP2 is critical to innate immunity-mediated paracrine damage to neurons involving COX-2 and iNOS. EP2 should be considered as a therapeutic target for suppression of microglial innate immunity-mediated damage in neurodegenerative diseases.
Insights
Microglial EP2 receptors are crucial for neuroinflammation and neuronal damage following innate immune activation. Targeting EP2 may protect against neurodegenerative diseases by suppressing microglial-induced damage.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Prostaglandin E2 (PGE2) signals through four E-prostanoid (EP) receptors (EP1-4).
- EP2 receptors are present on both glial and neuronal cells in the nervous system.
- Previous studies showed EP2 knockout mice were protected from neuronal damage after LPS injection.
Purpose of the Study:
- To investigate the specific role of microglial EP2 receptors in mediating neurotoxicity.
- To determine if microglial EP2 is essential for paracrine neurotoxicity following innate immune activation.
Main Methods:
- Primary murine microglia and neuron co-cultures were used.
- Lipopolysaccharide (LPS) was employed to activate innate immunity.
- Genetic deletion of microglial iNOS, pharmacological inhibition of COX-2, and addition of superoxide dismutase (SOD) and catalase were utilized.
Main Results:
- Microglial EP2 was essential for LPS-induced neurotoxicity and the upregulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2).
- Genetic deletion of iNOS, COX-2 inhibition, or addition of SOD/catalase abolished neurotoxicity in EP2-expressing microglia.
- These effects occurred independently of changes in cytokine levels.
Conclusions:
- Microglial EP2 receptors play a critical role in innate immunity-mediated paracrine neuronal damage.
- The damage involves the pathways of COX-2 and iNOS.
- EP2 presents a potential therapeutic target for mitigating microglial-driven neuroinflammation in neurodegenerative diseases.
