Bulk and single-cell transcriptomics reveal differential activation of the AGE-RAGE pathway and identification of key cell subpopulations in dilated cardiomyopathy

Dilated cardiomyopathy (DCM) presents with ventricular dilation and systolic dysfunction, yet its molecular underpinnings are not fully defined. The involvement of AGE-RAGE signaling in DCM pathogenesis remains largely unexplored. The differential engagement of this pathway in DCM was investigated, and responsible cell subsets and candidate molecular mediators were identified. This study integrated bulk RNA-seq data (GSE57338, GSE141910, GSE165303) and single-cell RNA-seq data (GSE183852). Supplementary analyses of cardiomyocyte populations from single-nucleus RNA-seq (snRNA-seq) data of GSE183852 were further performed. Using differential expression analysis, pathway enrichment analysis, cell clustering, GSVA, transcription factor regulatory network construction and other approaches, this study systematically characterized the activation pattern of the AGE-RAGE pathway in DCM. Key molecular expression and functional roles were validated in primary cardiac fibroblast experiments. The activity of the AGE-RAGE pathway was elevated in DCM, with a more pronounced effect observed in fibroblasts. MYH6, MYH10, and TGFB2 were identified as critical diagnostic genes for DCM, exhibiting robust diagnostic performance across multiple datasets. Single-cell analysis revealed that TGFB2 was highly expressed in the fibroblast subpopulation Fib1. Functional experiments confirmed that TGF-β1-induced fibrotic responses depend on AGE-RAGE pathway activation, which could be reversed by the RAGE inhibitor FPS-ZM1. This study suggests that the AGE-RAGE pathway exhibits cell-type-specific activation characteristics in fibroblasts of DCM, and indicates that genes such as TGFB2 may serve as potential biomarkers for DCM. These findings provide novel insights into the cellular and molecular mechanisms underlying DCM.