Interference with HMGB1 inhibits neuronal ferroptosis following spinal cord injury through targeting ACSL4

Spinal cord injury (SCI) refers to structural and functional impairments of the spinal cord resulting from various etiologies. Ferroptosis has been increasingly recognized as a critical contributor to neuronal damage following SCI. Therefore, this study aims to investigate the regulatory role of HMGB1 in neuronal ferroptosis of SCI rats and to explore its underlying mechanisms. Iron ion deposition, MDA and GSH levels, as well as the expressions of HMGB1, ACSL4, SLC7A11 and GPX4 in spinal cord tissue of SCI rats were measured at 24 h, 72 h and 1 week post-injury. Then, an in vitro neuronal ferroptosis model was established by treating primary rat spinal cord neurons with Erastin. Neuronal cells were transfected with lentiviral vectors for HMGB1 interference or ACSL4 overexpression. Iron ion levels, MDA content, GSH activity, and the expressions of HMGB1, ACSL4, SLC7A11 and GPX4 were measured. The interaction between HMGB1 and ACSL4 was assessed by co-immunoprecipitation assays. Finally, SCI rats were administered the HMGB1 inhibitor glycyrrhizic acid (GA) and the effects GA on the iron ion deposition, MDA and SOD levels, as well as the expressions of HMGB1, ACSL4, SLC7A11 and GPX4 in spinal cord tissues were evaluated. Iron ion deposition was observed in the spinal cord tissue of SCI rats, accompanied by increased levels of MDA, HMGB1 and ACSL4, as well as decreased levels of GSH, GPX4, and SLC7A11. These alterations exhibited a time-dependent pattern. The administration of GA in SCI rats significantly reduces iron ion deposition, decreases the levels of MDA, HMGB1 and ACSL4, and increases the levels of GSH, GPX4, and SLC7A11. Furthermore, cellular-level results demonstrated that interfering with HMGB1 could attenuate ferroptosis in rat spinal cord neurons through targeted suppression of ACSL4. Targeted suppression of ACSL4 expression through interference with HMGB1 inhibits neuronal ferroptosis in SCI rats.