Abstract 305: Single Cell RNA Sequencing of Adult Cardiac c-kit+ Cells in a Murine Lineage Tracing Model

A subset of adult cardiac resident cells defined by the stem cell factor tyrosine kinase receptor termed c-kit, are believed to have myogenic potential and are now being delivered via intracoronary infusion to presumably promote cardiac regeneration and improve ventricular function after ischemic cardiac injury. However, recent studies have shown that despite these benefits, c-kit+ progenitor cells in the adult murine heart are more inclined to take on an endothelial rather than cardiomyocyte lineage. To better define the factors involved in early differentiation of these resident cardiac progenitor cells and to distinguish distinct cell subpopulations, we performed single cell RNA sequencing on c-kit+ cells from Kit-Cre lineage traced GFP reporter mice versus total mesenchymal cells from the heart that were CD31- and CD45-. Cells were isolated by cardiac digestion and FACS was performed, positively sorting for the c-kit+ lineage while negatively sorting for CD31 and CD45 to eliminate endothelial and leukocyte progenitor contamination, respectively. Following this isolation, cells were examined to determine GFP reporter status and then submitted for single cell RNA sequencing using the Fluidigm A1 system. Clustering of 654 genes from this data identified 6 distinct subpopulations indicating various stages of early differentiation among CD31- and CD45-negative cardiac interstitial cells. Furthermore, comparison of GFP+ c-kit cells to the total non-GFP mesenchymal cells identified 75 differentially expressed transcripts. These unique gene signatures may help parse the genes that underlie cellular plasticity in the heart and define the best molecular lineages for transdifferentiation into cardiac myocytes.