Single-Cell RNA Sequencing Reveals Cellular Heterogeneity and Microenvironmental Remodeling in Human Ureteral Scar Stricture Tissue

This study aimed to construct a comprehensive single-cell transcriptomic atlas of human ureteral scar stricture tissue using single-cell RNA sequencing (scRNA-seq), to uncover cellular heterogeneity, subpopulation dynamics, and intercellular communication networks. Ureteral tissues were collected from three normal controls (CTR) and three patients with ureteral scar stricture (US). Single-cell suspensions were prepared using the MobiNova-100 platform and sequenced on the Illumina NovaSeq 6000 system. Data were analyzed using Seurat, Harmony, Monocle2 (for pseudotime trajectory analysis), CellChat (for cell-cell communication), and SCP (for GO/KEGG enrichment). Key findings were validated by multiplex immunofluorescence (IF) and immunohistochemistry (IHC). Eleven major cell types were identified, including epithelial, stromal, endothelial, and immune cells, each comprising distinct subpopulations. Compared to CTR tissues, US tissues exhibited an increased proportion of S100A8+ and MT1E+ basal epithelial cells with pro-inflammatory characteristics. Fibroblasts displayed substantial heterogeneity, with expansion of inflammatory fibroblasts and smooth muscle cell subsets. Endothelial cells (ECs) showed upregulated inflammatory and antigen presentation pathways. Macrophages exhibited mixed M1/M2 polarization, with enrichment of APOE+ and APOBEC3A+ subsets. Additionally, Th17, Treg, and CD8+ T cell populations were elevated. Cell-cell communication analysis revealed enhanced signaling among fibroblasts, ECs, and immune subsets, particularly via PERIOSTIN, collagen, and laminin pathways. This study presents the first high-resolution single-cell atlas of ureteral scar stricture tissue, revealing profound cellular heterogeneity and remodeling of the immune-stromal-epithelial landscape. The findings also highlight intensified intercellular communication within the fibrotic microenvironment, offering novel insights into disease pathogenesis and potential therapeutic targets.