IGF2BP1 exacerbates neuroinflammation and cerebral ischemia/reperfusion injury by regulating neuronal ferroptosis and microglial polarization.

BACKGROUND

Cerebral ischemia/reperfusion (I/R) injury induces neuronal ferroptosis and microglial phenotypic shifts, driving post-ischemic neurological deficits. This study examines the regulatory role of the N6-methyladenosine (m6A) reader insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) in coordinating these pathological processes through Keap1/Nrf2 signaling.

METHODS

Cerebral I/R injury was modeled in C57BL/6 mice via middle cerebral artery occlusion (MCAO) and in hippocampal neurons and microglia through oxygen-glucose deprivation/reperfusion (OGD/R). Pro-inflammatory microglial polarization was induced by LPS/IFN-γ stimulation. IGF2BP1's functional impacts were assessed through knockdown and overexpression approaches, with mechanistic evaluations focusing on ferroptosis biomarkers, microglial polarization states, and Keap1/Nrf2 pathway activity. A microglia-neuron co-culture system elucidated cellular crosstalk mechanisms.

RESULTS

MCAO-operated mice demonstrated upregulated IGF2BP1 expression accompanied by neuronal apoptosis and microglial M1 polarization. IGF2BP1 silencing significantly attenuated OGD/R-induced neuronal ferroptosis, evidenced by reduced iron overload (Fe), lipid peroxidation (MDA), and reactive oxygen species (ROS) alongside restored glutathione (GSH) levels, while concurrently enhancing GPX4 activity through Keap1/Nrf2 pathway regulation. This intervention further shifted microglial polarization toward the M2 phenotype, effectively mitigating neuroinflammatory responses. Importantly, the neuroprotective effects of IGF2BP1 knockdown were abolished upon Keap1 overexpression. Co-culture experiments revealed that IGF2BP1-depleted microglia suppressed neuronal ferroptosis via phenotypic reprogramming. In vivo validation confirmed that IGF2BP1 knockdown ameliorated neurological deficits and reduced ferroptosis markers in MCAO-challenged mice.

CONCLUSION

IGF2BP1 serves as a critical regulator of cerebral I/R injury by exacerbating neuronal ferroptosis and sustaining detrimental microglial activation. These findings nominate IGF2BP1 inhibition as a promising strategy for ischemic stroke intervention.