Single-Cell and Bulk RNA-Seq Profiling Identifies Cell Adhesion-Related Gene Signatures in Cerebral Ischemia-Reperfusion Injury

Cerebral ischemia-reperfusion injury (CIRI) involves complex secondary damage mechanisms, including oxidative stress, inflammation, and blood-brain barrier disruption, in which cell adhesion-related genes play a central role. Therefore, systematically elucidating the expression and regulation of cell adhesion-related genes (CARGs) is crucial for identifying new therapeutic targets to mitigate inflammatory infiltration and preserve barrier integrity. Both single-cell and bulk transcriptomic data were obtained from the Gene Expression Omnibus database. The single-cell data were processed using Seurat, and CARG activity was comprehensively assessed using five scoring algorithms, including UCell and AUCell. A combined machine learning framework incorporating Boruta algorithm, LASSO regression, and random forest was employed to screen for reliable diagnostic biomarkers. Furthermore, immune infiltration profiles were evaluated using CIBERSORT, regulatory networks were constructed, and molecular subtypes were identified through consensus clustering. Single-cell analysis revealed high CARG activity in endothelial cells, smooth muscle cells, and astrocytes. Machine learning identified four robust diagnostic biomarkers (Itgb1, Fn1, Pdlim5, Kdr) with excellent predictive accuracy (AUC=1) across multiple datasets. These biomarkers strongly correlated with immune cell infiltration, particularly macrophage polarization and mast cell activation, and successfully stratified CIRI samples into two distinct molecular subtypes. By integrating single-cell and transcriptomic data, this study systematically reveals the critical role of cell adhesion-related genes in CIRI. It identifies four core diagnostic genes that are closely associated with immune microenvironment remodeling and neuronal damage, thereby providing new molecular markers and a theoretical foundation for clinical diagnosis and treatment. Significance Statement Cerebral ischemia-reperfusion injury (CIRI) triggers persistent neuroinflammation and blood-brain barrier breakdown, yet reliable molecular biomarkers for early diagnosis and subtype stratification remain limited. Combining single-cell and bulk RNA-seq datasets, this work systematically characterizes cell adhesion-related gene (CARG) signatures in CIRI. We uncovered elevated CARG activity in endothelial cells, astrocytes and smooth muscle cells, and identified four core diagnostic genes (Itgb1, Fn1, Pdlim5, Kdr) with outstanding predictive performance. These genes are tightly linked to immune cell polarization and microenvironment remodeling, enabling classification of CIRI into distinct molecular subtypes. Our findings advance the understanding of cell adhesion-mediated secondary brain injury and offer promising candidate markers for future translational research and targeted therapeutic development in ischemic stroke.