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Updated: Nov 26, 2025
A Model of Epileptogenesis in Rhinal Cortex-Hippocampus Organotypic Slice Cultures
Published on: March 18, 2021
The complement C3-C3aR pathway mediates microglia-astrocyte interaction following status epilepticus
Yujia Wei1,2, Tingjun Chen1, Dale B Bosco1
1Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.
Abstract:
Gliosis is a histopathological characteristic of epilepsy that comprises activated microglia and astrocytes. It is unclear whether or how crosstalk occurs between microglia and astrocytes in the evolution of epilepsy. Here, we report in a mouse model of status epilepticus, induced by intracerebroventricular injection of kainic acid (KA), sequential activation of microglia and astrocytes and their close spatial interaction in the hippocampal CA3 region. Microglial ablation reduced astrocyte activation and their upregulation of complement C3. When compared to wild-type mice, both C3-/- and C3aR-/- mice had significantly less microglia-astrocyte interaction in response to KA-induced status epilepticus. Additionally, KA-injected C3-/- mice had significantly less histochemical evidence of neurodegeneration. The results suggest that the C3-C3aR pathway contributes to KA-induced neurodegeneration by mediating microglia-astrocyte communication. The C3-C3aR pathway may prove to be a potential therapeutic target for epilepsy treatment.
Insights
Microglia and astrocytes interact in epilepsy via the C3-C3aR pathway, driving neurodegeneration. Targeting this pathway may offer new epilepsy treatments.
Area of Science:
- Neuroscience
- Immunology
- Pathology
Background:
- Gliosis, characterized by activated microglia and astrocytes, is a hallmark of epilepsy.
- The precise mechanisms of microglia-astrocyte crosstalk in epilepsy pathogenesis remain largely unknown.
Purpose of the Study:
- To investigate the sequential activation and interaction of microglia and astrocytes in a mouse model of epilepsy.
- To elucidate the role of the complement system, specifically C3 and its receptor C3aR, in mediating microglia-astrocyte communication and subsequent neurodegeneration.
Main Methods:
- Induction of status epilepticus using intracerebroventricular kainic acid (KA) injection in mice.
- Utilized microglial ablation, C3 knockout (C3-/-), and C3a receptor knockout (C3aR-/-) mouse models.
- Assessed microglia-astrocyte interaction, complement C3 expression, and neurodegeneration through histochemical analysis.
Main Results:
- KA-induced epilepsy showed sequential activation and spatial interaction between microglia and astrocytes in the hippocampus.
- Microglial ablation attenuated astrocyte activation and complement C3 upregulation.
- C3-/- and C3aR-/- mice exhibited reduced microglia-astrocyte interaction and less neurodegeneration following KA-induced status epilepticus compared to wild-type mice.
Conclusions:
- The C3-C3aR pathway is crucial for mediating microglia-astrocyte communication in KA-induced epilepsy.
- This pathway significantly contributes to neurodegeneration in epilepsy.
- The C3-C3aR pathway represents a potential therapeutic target for epilepsy treatment.
