Integrative transcriptomic analysis identifies an oxidative stress-associated diagnostic signature for myocardial infarction.

Reactive oxygen species (ROS) play a pivotal role in myocardial infarction (MI), contributing to oxidative stress, inflammation, and tissue remodeling. However, ROS-related gene signatures with diagnostic and mechanistic relevance in MI remain insufficiently defined. Transcriptomic data from six MI cohorts were integrated, with GSE66360 as the training set and five datasets as external validation. Batch correction was performed using ComBat. ROS pathway activity was assessed by single-sample gene set enrichment analysis (ssGSEA). Differentially expressed genes (DEGs) shared across datasets were intersected with ROS-related genes to construct an elastic net logistic regression model. Model performance was evaluated using ROC, calibration, and decision curve analysis. SHAP analysis was conducted for interpretability. Upstream transcription factor and miRNA interactions were predicted, and single-gene GSEA was used to explore biological pathways. Immune infiltration and checkpoint expression were analyzed using multiple deconvolution algorithms. Human AC16 cardiomyocytes were used to explore the functions of ADAM9 in MI. To validate our findings in vivo, we established the mice MI model and performed histology, immunostaining, and qRT-PCR to examine the six signature genes. ROS pathway activity was consistently elevated in MI samples across all cohorts. A six-gene signature (MMP9, ADAM9, BST1, TLR4, CLEC7A, CYP1B1) showed strong diagnostic performance. SHAP analysis identified MMP9 as the top contributor. Regulatory network analysis highlighted NFKB1, STAT1, and miR-21-5p as upstream regulators. Functional enrichment revealed an association with inflammatory and immune pathways. Software algorithm predictions from patient blood cell samples showed that the MI sample exhibited increased infiltration of macrophages, dendritic cells, and fibroblasts, along with upregulation of immune and inflammatory genes. Several model genes correlated positively with endothelial cell infiltration. Function studies in human AC16 cardiomyocytes suggested that ADAM9 inhibited cardiomyocyte survival and enhanced oxidative stress. Experimental validation confirmed that all six genes were significantly upregulated at both mRNA and protein levels in infarcted mouse hearts. We identified a ROS-related six-gene diagnostic signature for MI, with strong performance and mechanistic links to immune activation and vascular remodeling. This model may aid early diagnosis and provide insight into redox-immune interplay in MI.