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.