ALKBH5 demethylates the m⁶A modification of SOCS3 in microglia/macrophages and alleviates neuroinflammation after brain injury.

Abstract

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 postinjury revealed a strong correlation between m⁶A modifications and genes enriched in microglia/macrophages. Furthermore, the m⁶A demethylase ALKBH5 was identified as a key regulator of dynamic m⁶A patterns at the injury site. ALKBH5 suppression in microglia/macrophages 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 <i>Socs3</i> 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.