Macrophage Precursor Cells from the Left Atrial Appendage of the Adult Heart Spontaneously Reprogram into a C-kit+/CD45- Stem Cell-Like Phenotype [Array analysis]. Mus musculus

The developmental origin of the c-kit expressing progenitor cell pool in the adult heart has remained elusive. Recently, it has been discovered that the injured heart is enriched with c-kit+ cells, which also express the hematopoietic marker CD45. In this study, we characterize the phenotype and transcriptome of the c-kit+/CD45+ cell population, originating from the left atrial appendage. These cells are defined as cardiac macrophage progenitors. We also demonstrate that the c-kit+/CD45+ progenitor cell population activates heart development, neural crest and pluripotency associated pathways in vitro, in conjunction with CD45 down-regulation, and acquire a c-kit+/lin- phenotype. This spontaneous reprogramming progresses further to a highly proliferative, partially myogenic phenotype. Our data suggests that c-kit+/lin- cells and cardiac macrophages have a common lineage origin possibly resolving some current conundrums in the field of cardiac regeneration. Overall design: Two different stem cell types were grown by altering the tissue digestion protocol. To investigate their transcriptional profiles we prepared RNA from two cell sorted replicates per cell type and from two left ventricular biopsy samples as controls.