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Updated: Sep 4, 2025
Identifying Microglia and Peripheral Infiltrating Macrophages in the Injured Spinal Cords Using Flow Cytometry
Published on: June 24, 2025
Microglia coordinate cellular interactions during spinal cord repair in mice
Faith H Brennan1,2, Yang Li3, Cankun Wang3
1Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA.
Abstract:
Traumatic spinal cord injury (SCI) triggers a neuro-inflammatory response dominated by tissue-resident microglia and monocyte derived macrophages (MDMs). Since activated microglia and MDMs are morphologically identical and express similar phenotypic markers in vivo, identifying injury responses specifically coordinated by microglia has historically been challenging. Here, we pharmacologically depleted microglia and use anatomical, histopathological, tract tracing, bulk and single cell RNA sequencing to reveal the cellular and molecular responses to SCI controlled by microglia. We show that microglia are vital for SCI recovery and coordinate injury responses in CNS-resident glia and infiltrating leukocytes. Depleting microglia exacerbates tissue damage and worsens functional recovery. Conversely, restoring select microglia-dependent signaling axes, identified through sequencing data, in microglia depleted mice prevents secondary damage and promotes recovery. Additional bioinformatics analyses reveal that optimal repair after SCI might be achieved by co-opting key ligand-receptor interactions between microglia, astrocytes and MDMs.
Insights
Microglia are crucial for spinal cord injury (SCI) recovery, coordinating cellular responses and promoting healing. Depleting microglia worsens outcomes, while restoring their signaling pathways aids repair.
Area of Science:
- Neuroscience
- Immunology
- Regenerative Medicine
Background:
- Traumatic spinal cord injury (SCI) induces neuroinflammation involving microglia and monocyte-derived macrophages (MDMs).
- Distinguishing microglial roles from MDMs in SCI is challenging due to similar in vivo markers.
Purpose of the Study:
- To elucidate the specific cellular and molecular roles of microglia in SCI.
- To identify therapeutic targets for enhancing SCI recovery by understanding microglial coordination.
Main Methods:
- Pharmacological depletion of microglia.
- Anatomical, histopathological, and tract tracing analyses.
- Bulk and single-cell RNA sequencing, with bioinformatics analysis.
Main Results:
- Microglia are essential for SCI recovery, mitigating tissue damage and improving functional outcomes.
- Microglia orchestrate responses in central nervous system (CNS)-resident glia and infiltrating leukocytes.
- Restoring specific microglial signaling pathways in depleted mice reversed secondary damage and promoted recovery.
Conclusions:
- Microglia play a vital role in coordinating the cellular and molecular response to SCI.
- Targeting microglial signaling pathways offers a promising therapeutic strategy for SCI.
- Optimizing SCI repair may involve leveraging ligand-receptor interactions between microglia, astrocytes, and MDMs.
