To identify critical Rnd3-expressing cardiac cell type in DCM, cardiac myocytes (CD45- PDGFR-α- CD31-), fibroblasts (CD45- PDGFR-α+), endothelial cells (CD45- CD31+), and macrophages (CD45+ F4/80+) were separated using flow cytometry. The gene discussed is PECAM1; the disease is familial dilated cardiomyopathy.