Enhanced expression of mesoderm marker genes in hESCs and hiPSCs by treating PD98059 and BMP4. (A) and (B) Relative expression levels of mesoderm (T and WNT3), endoderm (FOXA2 and FOXQ1), and ectoderm(ZIC1, SOX1, and PAX6) marker genes between experimental groups in hESCs and hiPSCs. The values are the mean ± SD of 3 independent experiments. A P value < .05 was considered to be statistically significant (*P < .05; n = 3). (C) Western blot analysis for phosphorylation of ERK1/2 and SMAD1/5/8 and expression of a stem cell marker (OCT4) and mesoderm markers (T, GATA2) in undifferentiated hESCs (control) and PDB4-treated hESCs. (D) Immunostaining for a stem cell marker (OCT4) and a mesoderm marker (T) in undifferentiated hESCs (control) and PDB4-treated hESCs. Scale bar is 200 μm. Abbreviations: Control, untreated hESCs; PD, PD98059; B4, BMP4; PDB4, hESCs treated with PD98059 and BMP4.