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

## TL;DR

This study maps gene activity in rat hearts after a heart attack and reperfusion, revealing distinct regions and identifying Piezo1 as a key player in calcium overload and potential therapeutic target.

## Contribution

The study identifies spatially distinct gene expression patterns in MIR injury and highlights Piezo1 as a novel mediator of Ca2+ dysregulation.

## Key findings

- Infarct cores show ferroptosis and mitophagy-related gene activity.
- Border zones are enriched with phagosome-related genes and smooth muscle cells.
- Piezo1 inhibition reduces Ca2+ overload in a reoxygenation model.

## Abstract

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 Ca2+ 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 Ca2+ dysregulation, and suggest Piezo1 as a potential therapeutic target for myocardial protection.

We employed spatially resolved transcriptomics to visualize and molecularly characterize the spatial distribution of gene expression profiles in the rats’ left ventricles following MIR injury. Further experiments indicated that cardiogenic Piezo1‐mediated calcium overload exacerbates MIR through the activation of matrix metalloproteinase 2‐ryanodine receptor 2/sarcoplasmic/endoplasmic reticulum Ca2+‐ATPase 2 signaling.