Spatiotemporal Transcriptomics of Human Cardiovascular Progenitors in Pig Hearts Identifies MIDKINE as a Positive Regulator of Neovascularization

Stem cell-based therapy has shown promise for regenerating infarcted heart tissue, yet the molecular dynamics and cellular fate of transplanted cells within the myocardium remain largely unexplored. In this study, we used time-series spatial transcriptomics to analyze the global gene expression profile of human pluripotent stem cell-derived cardiovascular progenitors (CVPs) transplanted into pigs at 1, 4, and 12 weeks post-chronic myocardial infarction (CMI). We employed bioinformatics tools, including ligand-receptor interaction and signaling pathway analysis, and identified MIDKINE (MDK), a human xenograft-derived chemokine, as a key regulator of neovascularization. These findings were validated through downstream bioinformatics analysis, immunohistochemistry, and in vitro genetic manipulation. Our results revealed important cardiac repair mechanisms, such as increased expression of markers associated with cardiac maturation, including genes related to metabolism, cell cycle regulation, calcium handling, sarcomere development, ribosome biogenesis, and fibrosis resolution. Notably, through ligand-receptor interaction analysis, we identified the ligand MDK as a promising target to enhance angiogenic responses in the pig heart following cellular transplantation. This provides a valuable foundation for understanding the mechanisms of cellular therapy in the context of degenerative heart disease. To further support our findings, we generated MDK-overexpressing cardiomyocytes and observed a significant increase in endothelial cell migration in transwell assays compared to controls (P-value < 0.05). For a deeper exploration of our transcriptomic data, we developed a spatially- and time-resolved transcriptomic Shiny application atlas of CVP xenografts in MI pig hearts during the critical post-transplantation recovery phase, enabling interactive exploration of gene expression profiles from our large animal models.