Figure 1.

Identification and Expression of a New Cardiac Progenitor-Specific Marker

(A) FACS analysis with the well-known cardiac progenitor markers Flk-1 and PDGFRα in undifferentiated induced pluripotent stem cells (iPSCs, group 1) and three cell lines at different stages of day 4-differentiation: group 2, spontaneously differentiated cells; group 3, cells differentiated by the established cardiac differentiation protocol; group 4, cells differentiated by the established cardiac differentiation protocol and sorted by Flk-1 and PDGFRα. (B) Microarray screening workflow for the four cell groups (n = 3). (C) Heatmap data from the microarray screening workflow. (D) Four candidate markers showing 2-fold upregulated expression are all G-protein–coupled receptors (GPCR): lysophosphatidic acid receptor 4 (LPAR4), Latrophilin 2 (LPHN2), chemokine (C-X-C motif) receptor 4 (CXCR4), and a regulator of G-protein signaling 5 (RGS5). (E) Schematic representation of the established cardiac differentiation protocol. (F) The real-time PCR analysis of the mRNA expression levels of the three candidates during cardiac differentiation. Error bars represent SEM, ∗∗∗p < 0.001, unpaired t test. n = 3 biological replicates. (G) FACS analysis of the protein expression levels of the three candidates during cardiac differentiation. All experiments were conducted at least in triplicate.