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Updated: Jul 15, 2026
A Model of Epileptogenesis in Rhinal Cortex-Hippocampus Organotypic Slice Cultures
Published on: March 18, 2021
Enhanced cell-to-cell contacts between activated microglia and pyramidal cell dendrites following kainic acid-induced
Sanae Hasegawa1, Masahiro Yamaguchi, Hiroshi Nagao
1Department of Physiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Abstract:
Microglia participate in immune responses in the brain. However, little is known about the contact-mediated interaction between microglia and neurons. We report here that the cell-to-cell contacts between microglial processes and dendrites of hippocampal CA1 neurons were dramatically increased in density and area following local injection of kainic acid (KA). A similar KA-induced increase in the degree of intercellular contacts was observed in mice lacking telencephalin (TLCN), a neuronal dendritic adhesion molecule of ICAM family. The results suggest that adhesive contacts independent of TLCN and contact-mediated interactions between microglia and dendrites were promoted by excitotoxic brain injury.
Insights
Excitotoxic brain injury, like that caused by kainic acid (KA), significantly increases contact between microglia and neuronal dendrites. This interaction is promoted even without the telencephalin (TLCN) adhesion molecule.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Microglia are key immune cells in the brain.
- The role of direct cell-to-cell contact between microglia and neurons is not well understood.
- Understanding these interactions is crucial for neuroinflammation research.
Purpose of the Study:
- To investigate the impact of excitotoxic brain injury on microglial-neuronal interactions.
- To explore the role of telencephalin (TLCN) in mediating these contacts.
Main Methods:
- Induction of excitotoxic injury using local kainic acid (KA) injection in mouse hippocampus.
- High-resolution imaging to analyze the density and area of cell-to-cell contacts between microglial processes and CA1 neuronal dendrites.
- Comparison of contact changes in wild-type mice versus mice lacking the TLCN gene.
Main Results:
- Kainic acid (KA) injection significantly increased the density and area of contacts between microglial processes and hippocampal CA1 neuronal dendrites.
- This increase in intercellular contacts was also observed in mice genetically deficient in telencephalin (TLCN).
- The findings indicate that KA promotes microglial-neuronal adhesion independently of TLCN.
Conclusions:
- Excitotoxic brain injury enhances contact-mediated interactions between microglia and neuronal dendrites.
- These interactions are promoted through mechanisms that do not rely on the TLCN adhesion molecule.
- The study highlights a novel aspect of neuroinflammation and microglial function during brain injury.
