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Updated: May 13, 2026
Isolation of Cortical Microglia with Preserved Immunophenotype and Functionality From Murine Neonates
Published on: January 30, 2014
Layer V cortical neurons require microglial support for survival during postnatal development
Masaki Ueno1, Yuki Fujita, Tatsuhide Tanaka
1Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan. ms-ueno@umin.ac.jp
Abstract:
Neurons require trophic support during neural circuit formation; however, how the cellular milieu contributes to neuronal survival remains unclear. We found that layer V cortical neurons require support from microglia for survival during postnatal development. Specifically, we found that microglia accumulated close to the subcerebral and callosal projection axons in the postnatal brain. Inactivation of microglia by minocycline treatment or transient ablation of microglia in CD11b-DTR transgenic mice led to increased apoptosis, specifically in layer V subcerebral and callosal projection neurons. CX3CR1 in microglia was required for the survival of layer V neurons. Microglia consistently promoted the survival of cortical neurons in vitro. In addition, we identified microglia-derived IGF1 as a trophic factor that maintained neuronal survival. Our results highlight a neuron-glia interaction that is indispensable for network formation during a specific period in the developing brain.
Insights
Microglia are essential for the survival of developing layer V cortical neurons. These immune cells provide crucial trophic support, specifically via insulin-like growth factor 1 (IGF1), for neuronal development and network formation.
Area of Science:
- Neuroscience
- Developmental Biology
- Immunology
Background:
- Neuronal development necessitates trophic support from the cellular environment.
- The precise mechanisms by which glial cells influence neuronal survival during circuit formation are not fully understood.
- Microglia, the resident immune cells of the brain, are increasingly recognized for their roles beyond immune surveillance.
Purpose of the Study:
- To investigate the role of microglia in supporting the survival of developing layer V cortical neurons.
- To identify the specific molecular mechanisms and trophic factors involved in this neuron-glia interaction.
Main Methods:
- Utilized minocycline treatment and CD11b-DTR transgenic mice for microglia inactivation and ablation.
- Examined neuronal apoptosis in layer V cortical neurons and their projections.
- Investigated the role of CX3CR1 signaling in microglia-neuron interactions.
- Performed in vitro co-culture experiments to assess microglial support for cortical neurons.
- Identified microglia-derived insulin-like growth factor 1 (IGF1) using molecular assays.
Main Results:
- Microglia were observed to accumulate near subcerebral and callosal projection axons during postnatal development.
- Inactivation or ablation of microglia led to increased apoptosis in layer V subcerebral and callosal projection neurons.
- CX3CR1 signaling in microglia was critical for the survival of these specific neuronal populations.
- Microglia demonstrated a consistent ability to promote cortical neuron survival in vitro.
- Microglia-derived IGF1 was identified as a key trophic factor mediating neuronal survival.
Conclusions:
- Microglia play an indispensable role in ensuring the survival of layer V cortical neurons during postnatal development.
- This neuron-glia interaction, mediated by factors like IGF1, is crucial for proper neural circuit formation.
- Targeting this microglial support mechanism may offer therapeutic avenues for developmental neurological disorders.
