Cortical Spreading Depolarization Triggers and Resolves Inflammatory Signaling in Migraine
Overview
This study elucidates the dynamic inflammatory signaling cascade initiated by cortical spreading depolarization (CSD) in neurons, astrocytes, and microglia, highlighting a transition from pro-inflammatory to anti-inflammatory responses. The findings support the role of astrocyte and microglial interactions in migraine headache development and resolution.
Background
Cortical spreading depolarization (CSD) is recognized as the neurophysiological basis of migraine aura and is hypothesized to trigger migraine headaches through inflammatory signaling. Neuronal stress induced by CSD activates inflammasome pathways, releasing pro-inflammatory mediators that stimulate astrocytes and potentially meningeal nociceptors. Understanding the resolution of this inflammation is crucial, as unresolved inflammation may contribute to chronic migraine pathology. This study investigates the temporal progression of inflammatory and anti-inflammatory signaling in CNS cell types following CSD in mice.
Data Highlights
Parameter
Observation
Time Post-CSD
HMGB1 release from neurons
Initial burst then cessation
Within hours
Caspase-1 activation
Peak activation
1 hour
Caspase-1 activation
Diminished levels
3–5 hours
NF-κB p65:p50 (pro-inflammatory) in astrocytes
Detected
Shortly after CSD
NF-κB p65:p50 (pro-inflammatory) in astrocytes
Disappeared
24 hours
NF-κB cRel:p65 (anti-inflammatory) in astrocytes
Persisted
24 hours
Microglial transcriptional profile
Shift towards anti-inflammatory, upregulation of chemokines/cytokines
Post-CSD
Key Findings
Neurons release high mobility group box 1 (HMGB1) immediately after CSD, which ceases within hours.
Caspase-1 activation peaks at 1 hour post-CSD and declines by 3–5 hours, indicating transient pro-inflammatory signaling.
Astrocytes exhibit both pro-inflammatory (NF-κB p65:p50) and anti-inflammatory (cRel:p65) NF-κB activity shortly after CSD, with a shift towards sustained anti-inflammatory signaling at 24 hours.
Microglia show transcriptional changes favoring an anti-inflammatory profile and upregulate chemokines and cytokines such as tumor necrosis factor, suggesting a supportive role in inflammation resolution.
Microglial gene upregulation related to chemotaxis and synaptic pruning implies involvement in synaptic repair mechanisms post-CSD.
Astrocytic inflammatory signaling may modulate meningeal nociceptor activity via astrocyte endfeet interfacing with subarachnoid and perivascular spaces, potentially contributing to headache initiation.
Clinical Implications
These findings underscore the importance of targeting astrocyte and microglial inflammatory pathways in migraine management, particularly in modulating the transition from pro-inflammatory to anti-inflammatory states. Therapeutic strategies that enhance inflammation resolution may help prevent headache persistence and chronicity. Understanding cell-specific inflammatory dynamics could guide development of novel anti-migraine agents.
Conclusion
CSD induces a complex, time-dependent inflammatory response involving neurons, astrocytes, and microglia, with a critical shift from pro-inflammatory to anti-inflammatory signaling that may underlie both headache initiation and resolution. This nuanced cellular interplay offers potential targets for therapeutic intervention in migraine.
References
Original Article 2024 -- Cortical Spreading Depolarization Induces Inflammatory Signaling Pathways: Implications for Headache Development
