NEMO-Binding Domain/IKKγ Inhibitory Peptide Alleviates Neuronal Pyroptosis in Spinal Cord Injury by Inhibiting ASMase-Induced Lysosome Membrane Permeabilization.

A short peptide termed NEMO-binding domain (NBD) peptide has an inhibitory effect on nuclear factor kappa-B (NF-κB). Despite its efficacy in inhibiting inflammatory responses, the precise neuroprotective mechanisms of NBD peptide in spinal cord injury (SCI) remain unclear. This study aims to determine whether the pyroptosis-related aspects involved in the neuroprotective effects of NBD peptide post-SCI.Using RNA sequencing, the molecular mechanisms of NBD peptide in SCI are explored. The evaluation of functional recovery is performed using the Basso mouse scale, Nissl staining, footprint analysis, Masson's trichrome staining, and HE staining. Western blotting, enzyme-linked immunosorbent assays, and immunofluorescence assays are used to examine pyroptosis, autophagy, lysosomal membrane permeabilization (LMP), acid sphingomyelinase (ASMase), and the NF-κB/p38-MAPK related signaling pathway.NBD peptide mitigated glial scar formation, reduced motor neuron death, and enhanced functional recovery in SCI mice. Additionally, NBD peptide inhibits pyroptosis, ameliorate LMP-induced autophagy flux disorder in neuron post-SCI. Mechanistically, NBD peptide alleviates LMP and subsequently enhances autophagy by inhibiting ASMase through the NF-κB/p38-MAPK/Elk-1/Egr-1 signaling cascade, thereby mitigating neuronal death. NBD peptide contributes to functional restoration by suppressing ASMase-mediated LMP and autophagy depression, and inhibiting pyroptosis in neuron following SCI, which may have potential clinical application value.

DADLE promotes motor function recovery by inhibiting cytosolic phospholipase A2 mediated lysosomal membrane permeabilization after spinal cord injury.

BACKGROUND AND PURPOSE: Autophagy is a protective factor for controlling neuronal damage, while necroptosis promotes neuroinflammation after spinal cord injury (SCI). DADLE (D-Ala2 , D-Leu5 ]-enkephalin) is a selective agonist for delta (δ) opioid receptor and has been identified as a promising drug for neuroprotection. The aim of this study was to investigate the mechanism/s by which DADLE causes locomotor recovery following SCI. EXPERIMENTAL APPROACH: Spinal cord contusion model was used and DADLE was given by i.p. (16 mg·kg-1 ) in mice for following experiments. Motor function was assessed by footprint and Basso mouse scale (BMS) score analysis. Western blotting used to evaluate related protein expression. Immunofluorescence showed the protein expression in each cell and its distribution. Network pharmacology analysis was used to find the related signalling pathways. KEY RESULTS: DADLE promoted functional recovery after SCI. In SCI model of mice, DADLE significantly increased autophagic flux and inhibited necroptosis. Concurrently, DADLE restored autophagic flux by decreasing lysosomal membrane permeabilization (LMP). Additionally, chloroquine administration reversed the protective effect of DADLE to inhibit necroptosis. Further analysis showed that DADLE decreased phosphorylated cPLA2 , overexpression of cPLA2 partially reversed DADLE inhibitory effect on LMP and necroptosis, as well as the promotion autophagy. Finally, AMPK/SIRT1/p38 pathway regulating cPLA2 is involved in the action DADLE on SCI and naltrindole inhibited DADLE action on δ receptor and on AMPK signalling pathway. CONCLUSION AND IMPLICATION: DADLE causes its neuroprotective effects on SCI by promoting autophagic flux and inhibiting necroptosis by decreasing LMP via activating δ receptor/AMPK/SIRT1/p38/cPLA2 pathway.

FGF-18 Protects the Injured Spinal cord in mice by Suppressing Pyroptosis and Promoting Autophagy via the AKT-mTOR-TRPML1 axis.

Spinal cord injury (SCI) is a severe medical condition with lasting effects. The efficacy of numerous clinical treatments is hampered by the intricate pathophysiological mechanism of SCI. Fibroblast growth factor 18 (FGF-18) has been found to exert neuroprotective effects after brain ischaemia, but its effect after SCI has not been well explored. The aim of the present study was to explore the therapeutic effect of FGF-18 on SCI and the related mechanism. In the present study, a mouse model of SCI was used, and the results showed that FGF-18 may significantly affect functional recovery. The present findings demonstrated that FGF-18 directly promoted functional recovery by increasing autophagy and decreasing pyroptosis. In addition, FGF-18 increased autophagy, and the well-known autophagy inhibitor 3-methyladenine (3MA) reversed the therapeutic benefits of FGF-18 after SCI, suggesting that autophagy mediates the therapeutic effects of FGF-18 on SCI. A mechanistic study revealed that after stimulation of the protein kinase B (AKT)-transient receptor potential mucolipin 1 (TRPML1)-calcineurin signalling pathway, the FGF-18-induced increase in autophagy was mediated by the dephosphorylation and nuclear translocation of transcription factor E3 (TFE3). Together, these findings indicated that FGF-18 is a robust autophagy modulator capable of accelerating functional recovery after SCI, suggesting that it may be a promising treatment for SCI in the clinic.