Regional and Cell Specific Bioactivity of Injectable ECM Biomaterials in MI through Spatial and Single Nucleus Transcriptomics
Myocardial infarctions (MI) affect 805,000 people per year in the United States. To mitigate the pathological effects of MI, we have developed and investigated pro-reparative decellularized extracellular matrix (ECM) hydrogels. However, no one has ever utilized single cell and spatially resolved transcriptomics to further probe how ECM can elicit pro-repair in an MI model. Thus, we utilize spatial transcriptomics and single nucleus RNA sequencing (snRNAseq) to further delineate the regional and cell-specific bioactivity of decellularized ECM hydrogels. ECM hydrogel subacute treatment induced cardiac resident macrophage preservation, fibroblast activation, increased vasculature development, and a cardiomyocyte development program. Similar findings of cardiomyocyte and vasculature development, alongside fibroblast development was found for chronic treatment. Thus, we depict the pro-reparative nature of decellularized ECM hydrogels on cardiac cell types and elucidate previously undiscovered therapeutic pathways, further demonstrating ECM's potential as an MI therapy. Overall design: Gene expression profiling of 10x Genomic Chromium single nucleus RNA-Seq or Visium spatial transcriptomics from the left ventricular myocardium ornshort axis sections  on injured Sprague Dawley female rats (225-250 g). Injuries include I/R (35 minutes of ischemia followed by reperfusion).