Celastrol alleviates acute spinal cord injury by inhibiting microglial pyroptosis via the Neat1/NLRP3 pathway.

Abstract

BACKGROUND: Spinal cord injury (SCI) is a devastating clinical condition. In SCI, secondary inflammatory responses following spinal cord compression exacerbate neuronal damage and functional deficits. The long noncoding RNA (lncRNA) Neat1 may be closely related to the NLRP3 inflammasome, and recent studies have shown that celastrol can inhibit pyroptosis and inflammation in SCI. OBJECTIVES: The aim of this study was to investigate whether celastrol can promote recovery from acute SCI by regulating the Neat1/NLRP3 axis, thereby modulating microglial pyroptosis and activation. METHODS: BV-2 cells were treated with celastrol (100 nM) for 1 h and then stimulated with lipopolysaccharide (LPS) and adenosine triphosphate (ATP). Following the establishment of the SCI model, mice received celastrol (1 mg/kg; intraperitoneal injection) for 7 consecutive days. Experiments were performed with appropriate sample sizes or replicates to ensure statistical power. RESULTS: Celastrol decreased the expression of the lncRNA Neat1 and reduced inflammation in mice SCI model. Celastrol also inhibited the protein expression of NLRP3, Cleaved-caspase-1, IL-1β and IL-18; while concurrently increased the anti-inflammatory cytokine IL-10.Critically, fluorescence in situ hybridization (FISH) and immunofluorescence (IF) staining revealed that Neat1 is primarily localized in the nucleus, and celastrol blocked its translocation to the cytoplasm following LPS/ATP stimulation in BV-2 cells. CONCLUSIONS: These observations suggest that celastrol suppresses microglial pyroptosis and activation by inhibiting the lncRNA Neat1/NLRP3 pathway and reducing the production of neuroinflammatory factors, thereby improving motor function recovery and thus treating acute SCI.