Quercetin alleviates intervertebral disc degeneration by disrupting CEBPB-HMGA1 interaction to suppress TNFA production and reduce ECM degradation.

BACKGROUND

Intervertebral disc degeneration (IVDD) is a highly prevalent degenerative disease related to macrophage M1 polarization and nucleus pulposus cells (NPCs) dysfunction. Quercetin is a common flavonoid found in various plants, and its therapeutic roles have been proved in several diseases. However, its protective role and mechanism in IVDD remain inadequately explored.

METHODS

Bioinformatics analyses were employed to identify differentially expressed genes in IVDD and to annotate their functions and pathways. Quercetin was prioritized for further investigation based on bioinformatic drug enrichment analysis, which identified it as a top candidate targeting IVDD-associated pathways, alongside its well-documented anti-inflammatory and ECM-modulating properties in prior literature. A rat IVDD model was established by punctured in vivo to evaluate the protective effects of quercetin. Mice macrophage RAW 264.7 cells were stimulated with lipopolysaccharide (LPS) to mimic IVDD to assess M1 polarization and its downstream effects in response to quercetin. Dual-luciferase reporter assay was conducted to confirm the regulation of transcriptional activity. CoIP-MS and ChIP-PCR were utilized to examine protein-protein interactions and DNA-protein interactions, respectively.

RESULTS

Bioinformatics analysis of GEO datasets (GSE56081, GSE15227) identified 51 differentially expressed genes (DEGs) in IVDD, with functional enrichment revealing their significant association with extracellular matrix (ECM) organization and cell adhesion pathways. Drug enrichment analysis identified quercetin as the most significant phytochemical candidate after calcium, with established roles in ECM and inflammation pathways. In vivo experiments demonstrated that quercetin significantly mitigated puncture-induced disc degeneration by modulating ECM and adhesion-related pathways. Additionally, quercetin effectively attenuated LPS-induced macrophage M1 polarization in vitro, leading to reduced apoptosis of nucleus pulposus cells (NPCs) and decreased ECM degradation. Mechanistic analyses revealed that quercetin suppressed the expression and transcriptional activity of CEBPB by disrupting its interaction with HMGA1, which subsequently led to reduced transcription of the pro-inflammatory gene TNFA.

CONCLUSION

Quercetin suppressed CEBPB expression and transcriptional activity by disrupting the interaction between CEBPB and HMGA1, which in turn reduced the transcription of TNFA. This research established a foundation for further exploration of quercetin's molecular mechanisms and its therapeutic potential in degenerative disc diseases.