Juglone promotes spinal cord injury recovery by suppressing pyroptosis and necroptosis through FOS/USP53/ubiquitination

BACKGROUND: Spinal cord injury (SCI) is a central nervous system (CNS) disorder, and it often results in severe neuronal damage. However, there are still no effective treatments for SCI, so it is important to explore and identify effective therapeutic strategies. As a natural compound extracted from walnuts, juglone has been previously reported to exhibit various biological activities, including anti-tumor and anti-inflammatory effects, but the effects on central nerve system are still blank. PURPOSE: This study aims to evaluate the therapeutic effects of juglone in spinal cord injury and elucidate its molecular mechanisms in neuroprotection. STUDY DESIGN: In vitro neuronal OGD/R experiments and in vivo spinal cord injury model experiments were employed to investigate the neuroprotective effects of juglone on neurons. METHODS: Neuronal OGD/R models and spinal cord injury models were used to detect the neuroprotective effect of juglone. Immunofluorescence, Western Blot and ELISA were employed to investigate the effects of juglone on necroptosis and pyroptosis of neurons. RNA-Seq analysis, immunoprecipitation, Western Blot, qRT-PCR, immunofluorescence and ChIP-qPCR were utilized to elucidate the molecular mechanism of its neuroprotective effect. RESULTS: Juglone can inhibit necroptosis and pyroptosis both in vivo and in vitro, thereby exerting neuroprotective effects. Mechanistically, we identify a novel FOS/USP53 signaling axis, in which juglone suppresses the expression of FOS that directly regulates the deubiquitinating enzyme USP53. Reduced FOS expression leads to the downregulation of USP53, thereby promoting the ubiquitination and degradation of MLKL and GSDMD. This cascade ultimately alleviates necroptosis and pyroptosis in injured neurons. CONCLUSION: Juglone is a potential neuroprotective drug that exerts its effect by inhibiting necroptosis and pyroptosis through the FOS/USP53/ubiquitination signaling axis. These findings provide a novel potential drug target for the treatment of spinal cord injury.