Identification of Ferro-Aging-Related Biomarkers for Ulcerative Colitis Through Integrated Machine Learning, Single-Cell Analysis, and Spatial Transcriptomics.

Ulcerative colitis (UC) is characterized by chronic mucosal inflammation, epithelial injury, oxidative stress, and marked molecular heterogeneity. Ferro-aging has recently been proposed as an ACSL4-associated, iron-dependent aging-related state in primates, but whether its associated transcriptional features are relevant to chronic mucosal inflammatory disease remains unclear. Here, we integrated bulk transcriptomics, machine learning, single-cell RNA sequencing, spatial transcriptomics, and immunohistochemical validation of clinical tissue samples to characterize ferro-aging-related features in UC and identify associated biomarkers. Ferro-aging-related activity was quantified using GSVA and GSEA and was increased in UC, particularly in active disease, with strong associations with inflammatory response, oxidative stress, epithelial injury, and immune-cell infiltration. Transcriptomic stratification further identified a ferro-aging-high state characterized by enhanced inflammatory and tissue-remodeling signatures. WGCNA and LASSO logistic regression generated a five-gene diagnostic model that showed strong performance in the discovery and validation cohorts and was further validated in an independent external cohort (AUC = 0.992, 95% CI 0.979-1.000). Single-cell analysis localized ferro-aging-related activity and prioritized genes mainly to endothelial, fibroblast, and myeloid compartments, while CellChat suggested enhanced myeloid-centered communication involving MIF-CD74/CD44 and collagen-CD44 interactions. Spatial transcriptomics and immunohistochemistry further supported increased CHST15 and MSN expression in UC mucosa. Exploratory candidate-ligand analyses additionally identified Chst15-IN-1 and Polyphyllin VII for future experimental investigation. Collectively, these findings identify CHST15 and MSN as ferro-aging-related biomarkers linking mucosal inflammation, immune-stromal remodeling, and disease-associated tissue organization in UC.