NINJ1 monoclonal antibody alleviates neuroinflammation and promotes functional recovery after spinal cord injury by suppressing pyroptosis-mediated DAMPs release.

BACKGROUND

Secondary spinal cord injury (SCI) involves intense neuroinflammation driven by pyroptosis and damage-associated molecular patterns (DAMPs). Targeting NINJ1, an executioner protein for plasma membrane rupture, may break this cycle.

METHODS

A mouse contusion SCI model was used, with groups including Sham, Vehicle, Methylprednisolone, and low/high-dose NINJ1 monoclonal antibody (mAb). Functional recovery was assessed by BMS scoring and gait analysis. Histopathology and molecular changes (neuronal survival, pyroptosis proteins GSDMD/NLRP3/Caspase-1, microglial polarization markers, and related pathways) were analyzed at 14 dpi. HMGB1 release was quantified. An in vitro co-culture model of glutamate-injured HT22 neurons and BV2 microglia validated the effects.

RESULTS

NINJ1 mAb treatment significantly improved motor function and reduced pathology versus controls. It enhanced neuronal survival, suppressed pyroptosis executers (GSDMD, while NINJ1 mRNA expression remained unchanged), and decreased HMGB1 release. The treatment shifted microglial polarization from pro-inflammatory M1 to anti-inflammatory M2, correlating with reduced nuclear p-NF-κB p65 and increased p-STAT3. In vitro, NINJ1 mAb directly protected neurons and suppressed microglial M1 polarization and pro-inflammatory cytokine release.

CONCLUSION

The NINJ1 monoclonal antibody promotes recovery after SCI by inhibiting pyroptotic membrane rupture, reducing DAMP release, and modulating microglia toward an anti-inflammatory phenotype, presenting a novel therapeutic strategy.