Fig 1: Similarity of amniotic epithelial stem cells (AESCs) to early stage immature keratinocytes (KCs). (a) Heatmap of keratin family genes revealed specific and distinct patterns in AESCs and KCs. (b) Expression of undifferentiated (KRT5 & KRT14) and differentiation (KRT1 & KRT10) genes in AESCs detected by qRT-PCR. (c) KRT14 and KRT10 immunostaining in the amnion, fetal skin (at 24 weeks gestation) and adult foreskin. (d) KRT7 and KRT19 immunostaining in the amnion, fetal skin (at 24 weeks gestation) and adult foreskin. (e) Heatmap reveals that critical markers of early stage KCs were highly expressed in AESCs. (f) PTTG1, CDC20, and PCLAF immunostaining in the amnion, fetal skin (at 24 weeks gestation) and adult foreskin. (g) Heatmap of pseudotime-dependent genes involved in keratinocyte differentiation (Wang et al. [22]) shows that genes enriched in early stage KCs were highly expressed in AESCs (top to bottom corresponds to early stage to late stage). (h) Principal component analysis indicated that AESCs were closer to undifferentiated neonatal KCs (nKC). FB, fibroblast; AESC, amnion epithelial stem cell; KC, (adult) keratinocyte; nKC, neonatal KC; DnKC, differentiated neonatal KC (induced by adding 1.2 mM CaCl2) [23]. Bars represent relative values (mean ± SD) calculated from at least three independent experiments. Student’s t test was used to calculate p values. Scale bar = 100 μm (c); 50 μm (d,f).