Single-cell combined transcriptome explores the molecular mechanism of purine metabolism in keloids

Keloid disease (KD) is a benign skin tumor; however, the mechanism of purine metabolism-related genes (PMRGs) in KD remains unclear. This study aimed to identify key PMRGs in KD and clarify their regulatory mechanisms.

Three KD-related datasets (GSE145725, GSE7890, and GSE163973) and 163 PMRGs were analyzed. Differentially expressed PMRGs (DE-PMRGs) were identified by intersecting differentially expressed genes (DEGs) with PMRGs in GSE145725. Key genes were screened through protein-protein interaction (PPI) analysis and validated in GSE145725 and GSE7890. RT-qPCR confirmed expression levels in clinical specimens. Gene set enrichment analysis (GSEA), immune infiltration analysis, and regulatory networks examined the mechanisms of key genes. Single-cell analysis of GSE163973 identified key cell types, followed by pseudo-time and cell communication analyses.

Sixteen DE-PMRGs were identified from 1537 DEGs. RRM2 and PRPS1 were identified as key genes after PPI, ROC curve, and expression analyses. RT-qPCR revealed significantly increased PRPS1 and decreased RRM2 expression in KD tissues (P < 0.001). Both genes were co-enriched in proteasome, cell cycle, and spliceosome pathways. Immune infiltration showed RRM2 positively correlated with resting memory CD4 + T cells, whereas PRPS1 negatively correlated with monocytes. PRPS1 was potentially regulated by hsa-miR-216a-5p and 18 lncRNAs, with both genes regulated by IRF1. Neural and endothelial cells were identified as key cell types with high gene expression, showing differentiation at distinct stages. Endothelial cells exhibited strong interactions with fibroblasts.

RRM2 and PRPS1 are pivotal purine metabolism-related genes affecting KD pathogenesis, providing insights for KD diagnosis and therapeutic targets.