ALKBH5 Demethylates the m6A Modification of SOCS3 in Microglia/Macrophages and Alleviates Neuroinflammation after Brain Injury [scRNA-seq]

Microglia/macrophage-induced neuroinflammation plays a crucial role in the progression of traumatic brain injury (TBI). However, the involvement of N6-methyladenosine (m6A) RNA modifications in this process remains elusive. Single-cell RNA sequencing (scRNA-seq) and m6A RNA immunoprecipitation sequencing (MeRIP-seq) across multiple time points post-injury revealed a strong correlation between m6A modifications and genes enriched in microglia/macrophage. Furthermore, the m6A demethylase ALKBH5 was identified as a key regulator of dynamic m6A patterns at the injury site. ALKBH5 suppression in microglia/macrophage exacerbated neuroinflammation in vitro and worsened neurological deficits in controlled cortical impact (CCI) models. MeRIP-qPCR and RNA pull-down assays revealed SOCS3 was a downstream target of ALKBH5-mediated m6A demethylation. This demethylation stabilized Socs3 mRNA and enhanced its protein expression, which in turn suppressed neuroinflammation via inhibiting the JAK2-STAT3 pathway. Conversely, SOCS3 depletion impaired functional recovery after injury. These findings unveiled a critical ALKBH5-m6A-SOCS3 regulatory axis that mitigated microglia/macrophage-driven neuroinflammation after TBI, underscoring its potential as a therapeutic intervention target for TBI progression. Cortical tissues from mouse brains in the sham group and at 1, 3, 7, and 14 days following traumatic brain injury were minced and enzymatically dissociated for single-cell RNA sequencing.