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Updated: Jun 23, 2026
Isolation of Cortical Microglia with Preserved Immunophenotype and Functionality From Murine Neonates
Published on: January 30, 2014
Neuronal exosomal miR-25-3p attenuates M1 microglial activation and neurotoxicity by targeting TLR4 to regulate the
Guangjun Hu1, Sarulatuya1, Siyu Du1
1Department of Anesthesiology, Wuhan Third Hospital/Tongren Hospital of Wuhan University, Wuhan, Hubei Province, China.
Background:
Perioperative neurocognitive disorders (PND) are severe postoperative complications in the elderly, with neuroinflammation driven by pro-inflammatory M1 microglia being a core pathological mechanism. This study aimed to investigate the role of neuron-derived exosomes in regulating microglial polarization and its underlying molecular mechanism.
Methods:
We utilized a neuron-microglia transwell co-culture system. By modulating microRNA-25-3p (miR-25-3p) in neurons or Toll-like receptor 4 (TLR4) in microglia, we assessed microglial M1/M2 polarization, TLR4/NF-κB pathway activation, and subsequent neurotoxicity using qRT-PCR, Western Blot, flow cytometry, and dual-luciferase reporter assays.
Results:
Neuronal exosomes were effectively internalized by microglia. Exosomal miR-25-3p suppressed the activation of the TLR4/MyD88/NF-κB signaling pathway by directly targeting the 3'-UTR of TLR4. This significantly inhibited microglial polarization towards the pro-inflammatory M1 phenotype and reduced the release of pro-inflammatory cytokines. Functionally, this process attenuated M1 microglia-mediated neuronal apoptosis, oxidative stress, and functional impairment. Direct manipulation of TLR4 expression in microglia confirmed its pivotal role in this regulatory axis.
Conclusion:
Our findings systematically demonstrate that neurons can release exosomes carrying miR-25-3p to target and suppress the microglial TLR4/NF-κB signaling pathway, thereby inhibiting M1 polarization and alleviating neurotoxicity. This discovery deepens the understanding of PND pathophysiology and provides a theoretical basis and potential therapeutic targets for novel PND treatment strategies targeting neuron-glia communication.
Insights
Neurons release exosomes with microRNA-25-3p to suppress Toll-like receptor 4 signaling in microglia. This inhibits M1 polarization, reducing neuroinflammation and neurotoxicity, offering potential treatments for perioperative neurocognitive disorders.
Area of Science:
- Neuroscience
- Immunology
- Molecular Biology
Background:
- Perioperative neurocognitive disorders (PND) are significant in the elderly, linked to neuroinflammation from M1 microglia.
- Understanding the mechanisms of microglial polarization is crucial for PND treatment.
Purpose of the Study:
- To investigate how neuron-derived exosomes regulate microglial polarization.
- To elucidate the molecular mechanisms involved in this neuron-glia communication.
Main Methods:
- A neuron-microglia co-culture system was used.
- MicroRNA-25-3p in neurons and Toll-like receptor 4 (TLR4) in microglia were modulated.
- Microglial polarization, TLR4/NF-κB pathway activation, and neurotoxicity were assessed via qRT-PCR, Western Blot, flow cytometry, and dual-luciferase assays.
Main Results:
- Neuronal exosomes containing miR-25-3p were internalized by microglia.
- Exosomal miR-25-3p suppressed the TLR4/MyD88/NF-κB pathway by targeting TLR4.
- This reduced M1 microglia polarization, pro-inflammatory cytokine release, and subsequent neuronal damage.
Conclusions:
- Neurons use exosomes carrying miR-25-3p to inhibit microglial TLR4/NF-κB signaling, reducing M1 polarization and neurotoxicity.
- This study provides insights into PND pathophysiology and potential therapeutic targets for neuron-glia communication.
