Integrated bioinformatic analysis of biomarkers, pathways, and immune cell infiltration in ossification of the ligamentum flavum

BACKGROUND: Ossification of the ligamentum flavum (OLF) represents a pathologic condition contributing to spinal stenosis. Its underlying molecular mechanisms have not been fully elucidated. The present study aimed to identify gene expression alterations and associated molecular pathways in OLF through comprehensive bioinformatic analysis. METHODS: Gene expression profiles from GSE113212 were analyzed to identify differentially expressed genes (DEGs) between OLF and non-OLF tissues. Functional enrichment was assessed by GO and KEGG analyses. A protein-protein interaction (PPI) network was constructed to screen hub genes, while immune cell infiltration was quantified using CIBERSORT. Gene Set Variation Analysis (GSVA) and Gene Set Enrichment Analysis (GSEA) were employed to explore pathway-level dysregulation. RESULTS: A total of 148 DEGs were identified, including 118 downregulated and 30 upregulated genes in OLF tissues compared to non-OLF controls. Functional analyses revealed significant enrichment in muscle contraction-related processes, immune responses, and cytokine-cytokine receptor interactions. FN1, EGFR, and ACTA1 were identified as key hub genes. GSEA highlighted the activation of epithelial-mesenchymal transition (EMT), glycolysis, and inflammatory responses pathways in OLF. Immune infiltration analysis demonstrated distinct alterations in dendritic cells, macrophages, and eosinophils, with hub genes exhibiting strong correlations with specific immune cell subsets. CONCLUSION: This study uncovered possible molecular mechanisms driving OLF, emphasizing the interplay between immune-related pathways and key fibrotic regulators (FN1, EGFR, and ACTA1). These findings offer novel insight into the immune microenvironment of OLF and suggest potential targets for therapeutic intervention.