Spatial Transcriptional Heterogeneity in the Infarct Core and Its Surrounding Regions Targeting Piezo1 Signals in Rats With Myocardial Ischemia-Reperfusion Injury.

Myocardial ischemia-reperfusion (MIR) injury is a major cause of cardiac dysfunction, but the spatial heterogeneity of its underlying molecular programs remains unclear. In this study, we applied Visium spatial transcriptomics to generate gene expression maps of rat left ventricles after MIR and identified distinct regional features. The border zones were enriched with phagosome-related genes, incomplete infarct areas showed activation of MAPK, IL-17, and osteoclast differentiation pathways, while the infarct cores were characterized by ferroptosis and mitophagy-related genes. To further resolve the cellular basis, we integrated single-cell RNA sequencing with RCTD deconvolution and found immune cell infiltration in infarct zones, neutrophil enrichment in incomplete infarct areas, and smooth muscle cell predominance in border zones. Both spatial and single-cell analyses revealed altered expression of Piezo1, RyR2, MMP2, and SERCA2, which was further validated by Western blot and immunofluorescence co-staining with ACTN2. Pseudotime analysis demonstrated selective enrichment and dynamic activation of Piezo1 in specific cardiomyocyte subclusters. Functional validation using a hypoxia/reoxygenation model confirmed that reoxygenation induced marked intracellular Ca(2+) accumulation, which was attenuated by the Piezo1 inhibitor GsMTx4. Together, these findings delineate the spatial heterogeneity of MIR injury, identify Piezo1 as a key mediator of Ca(2+) dysregulation, and suggest Piezo1 as a potential therapeutic target for myocardial protection.