Identification and Mechanism Research of Oxidative Stress-Related Biomarkers in Oral Lichen Planus

Background: Oxidative stress (OS) plays an important role in oral lichen planus (OLP) development; however, the precise functions of the genes associated with OS (OSRGs) remain unclear. This study aimed to identify and characterize OS-linked molecular markers in OLP. Methods: Data were obtained from the GSE38616 and GSE211630 datasets, along with 467 OSRGs. Candidate genes were identified by cross-referencing differentially expressed genes with OSRGs. Biomarkers were then selected through a protein-protein interaction network analysis using Cytoscape. Functional enrichment analysis, regulatory network mapping, therapeutic compound prediction, molecular docking simulations, and RNA modification profiling were also performed. Single-cell RNA sequencing was used to characterize biomarker distribution among the distinct cell populations. Gene expression was validated using quantitative real-time PCR (qRT-PCR). Results: Five genes emerged as key biomarkers: TGFB1, KLF4, TNF, NQO1, and MMP9. Functional enrichment analysis revealed that these markers are involved in immune regulatory pathways between lymphoid and nonlymphoid cellular compartments. Network analysis identified hsa-miR-449a and hsa-miR-449b-5p as potential regulators of NQO1 and KLF4. Pharmaceutical screening identified several potential therapeutic compounds, such as meropenem anhydrous and hydroxyurea, which exhibit targeted binding affinity for key biomarkers. Docking simulations indicated robust binding interactions (binding energies < -5 kcal/mol) for most compound-biomarker combinations, excluding the KLF4-hydroxyurea pairing. In addition, putative m6A methylation sites were identified in the TNF, KLF4, and TGFB1 transcripts. Single-cell analysis identified T lymphocytes as the primary cell type of interest, with TGFB1 expression increasing progressively during T-cell maturation. Validation by qRT-PCR confirmed the transcriptomic results, demonstrating elevated expression of TGFB1, TNF, and MMP9, along with reduced NQO1 expression in OLP tissues. Conclusions: TGFB1, KLF4, TNF, NQO1, and MMP9 were identified as potential OS-associated biomarkers in OLP. These findings provide insights into disease mechanisms and reveal potential therapeutic targets.