Atf3 Promotes Spinal Cord Injury by Exacerbating Neuronal Oxidative Stress and Inflammation via the NF-κB Signaling Pathway.

Background: Spinal cord injury (SCI) is a central nervous system disorder characterized by oxidative stress and inflammatory responses. Activating transcription factor 3 (Atf3) is an early-response stress-regulating gene whose abnormal upregulation exacerbates oxidative stress and inflammation. However, despite its known association with oxidative stress, the mechanism of Atf3 in SCI remains incompletely understood. This study aimed to investigate the role and mechanisms of Atf3 in SCI. Methods: Bioinformatics analysis was performed using multiple GEO datasets to identify hub genes and key signaling pathways associated with post-SCI oxidative stress. The rat SCI model and a lipopolysaccharide (LPS)-induced PC12 cell injury model were established in vivo and in vitro to investigate whether Atf3 could ameliorate SCI progression, neuronal damage, oxidative stress, and inflammation. Chromatin immunoprecipitation quantitative PCR (ChIP-qPCR) and luciferase reporter assays were used to analyze the interaction between Atf3 and NF-κB/p65, as well as the promoter activity of the p65 gene. Finally, the NF-κB signaling pathway was activated to observe the role of Atf3 in neuronal injury and SCI. Results: Bioinformatics analysis revealed significant enrichment of Atf3 and the NF-κB signaling pathway in SCI datasets. Atf3 primarily colocalized with NeuN but minimally with GFAP or Iba-1. Knockdown of Atf3 significantly alleviated SCI damage, reduced oxidative stress (decreased MDA/MPO and increased SOD/GSH levels), and suppressed inflammation (reduced TNF-α, IL-1β and IL-6 levels) in both SCI rats and LPS-treated PC12 cells. However, activation of NF-κB counteracted these protective effects. ChIP-qPCR and luciferase reporter assays demonstrated that Atf3 overexpression enhanced its binding to the p65 promoter and promoted NF-κB/p65 activation, whereas Atf3 knockdown reversed these effects. Conclusion: Downregulation of Atf3 mitigates oxidative stress and inflammation in SCI, potentially by regulating neuronal biological functions via the NF-κB pathway. These findings provide a theoretical foundation for understanding SCI pathogenesis and identifying therapeutic targets.