• Epithelial cells are identified as the key cell subpopulation in diabetic foot ulcer pathogenesis via single-cell transcriptomics.
• S100A14 and SFN are novel biomarkers significantly upregulated in diabetic foot ulcer tissues and validated in rat models.
• Integration of single-cell and bulk transcriptomics with WGCNA/hdWGCNA reveals robust gene modules associated with diabetic foot ulcers.
• These findings provide potential therapeutic targets for diabetic foot ulcer treatment.