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Updated: Apr 29, 2026
Isolation and Flow Cytometric Assessment of Neuroimmune Interactions in a Mini-Stroke Murine Model
Published on: June 20, 2025
Lactate modulates microglial M2 polarization via H3K9 lactylation in ischemic stroke
Bingwei Li1, Kan Xu1, Jinlu Yu1
1Department of Neurosurgery, First Hospital of Jilin University, Changchun, Jilin Province, China.
Background And Objectives:
Ischemic stroke triggers pathological neuroinflammation primarily mediated by microglial activation. However, the epigenetic impact of lactate, a metabolite that accumulates during cerebral ischemia, on this process has not been comprehensively investigated. This study aimed to determine whether lactate influences microglial polarization through histone lactylation during prolonged cerebral ischemia.
Methods:
In vitro models using lactate-treated BV-2 microglia and in vivo models of transient middle cerebral artery occlusion (MCAO) mice were established. Analyses were conducted at 4 to 12 h post-occlusion. Our comprehensive analysis included H3K9la-targeted CUT& Tag sequencing, Nrf2 promoter-specific ChIP-qPCR, flow cytometry for polarization markers, cytokine enzyme-linked immunosorbent assays (ELISAs), and neuronal viability assays.
Results:
Under ischemic conditions, lactate markedly increased H3K9 lactylation, with selective enrichment at Nrf2 promoters. This epigenetic modification resulted in a phenotypic shift toward anti-inflammatory M2 states in microglia, both in vitro and in vivo. Mechanistically, H3K9la activated the Nrf2/HO-1 pathway, effectively suppressing nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling and significantly reducing pro-inflammatory cytokine secretion. Importantly, conditioned medium derived from lactate-treated microglia mitigated the neurotoxic efects induced by microglia to some extent.
Conclusion:
Our findings suggest that lactate confers neuroprotection via epigenetic activation of Nrf2 via H3K9la, thereby polarizing microglia towards inflammation-resolving states. This finding uncovers a novel metabolic-epigenetic target for therapeutic intervention in ischemic stroke.
Insights
Lactate reduces brain damage after ischemic stroke by epigenetically activating the Nrf2 pathway, shifting microglia to an anti-inflammatory state. This metabolic-epigenetic mechanism offers a new therapeutic target for stroke treatment.
Area of Science:
- Neuroscience
- Epigenetics
- Metabolism
Background:
- Ischemic stroke causes neuroinflammation via microglial activation.
- The epigenetic role of lactate in microglial response during ischemia is unclear.
- This study investigates lactate's impact on microglial polarization via histone lactylation.
Purpose of the Study:
- To determine if lactate influences microglial polarization through histone lactylation.
- To explore the epigenetic mechanisms underlying lactate's effects on microglia.
- To assess the therapeutic potential of lactate-mediated microglial modulation in ischemic stroke.
Main Methods:
- Utilized in vitro (BV-2 microglia) and in vivo (MCAO mice) models.
- Performed H3K9la CUT&Tag sequencing and Nrf2 promoter ChIP-qPCR.
- Analyzed microglial polarization, cytokine release (ELISA), and neuronal viability.
Main Results:
- Lactate increased H3K9 lactylation, particularly at Nrf2 promoters.
- This epigenetic change promoted an anti-inflammatory M2 microglial phenotype.
- Lactate activated Nrf2/HO-1, suppressed NF-κB, reduced inflammation, and protected neurons.
Conclusions:
- Lactate confers neuroprotection by epigenetically activating Nrf2 via H3K9la.
- Lactate polarizes microglia towards inflammation-resolving states.
- This metabolic-epigenetic pathway is a novel therapeutic target for ischemic stroke.
