Extensive tissue-regenerative capacity of neonatal human keratinocyte stem cells and their progeny
J. Clin. Invest. Amy Li, et al. 113:390 doi:10.1172/JCI19140 [Go to this article.]

Figure 3
Epithelial sheets generated from all fractions (KSCs, TA cells, and differentiating cells) exhibit appropriate temporal and spatial expression of differentiation markers. (a–l) Epithelial tissue regenerated by 4.5 × 10⁴ KSCs (a, d, g, and j), TA cells (b, e, h, and k), and differentiating cells (c, f, i, and l) cocultured with p1 DEs express the differentiation markers K10 (a–c), involucrin (d–f), and filaggrin (g–i) suprabasally and contain a β1 integrin–positive basal layer (j–l). Nuclei were counterstained with propidium iodide. (m–r) Epithelial sheets derived from epidermal stem cells reexpress K15 uniformly in the basal layer. Organotypic cultures generated by KSCs (m and p), TA cells (n and q), and differentiating cells (o and r) on p1 DEs (m–o) and p7 DEs (p–r) at day 14, stained for K15 (FITC) and K16 (Texas red). Suprabasal K16 expression was observed in epithelium derived from all fractions under all conditions, indicating that the keratinocytes were activated in these cultures. K15 expression was only detected when basal keratinocytes were cultured on p7 DEs and not on p1 DEs. Notably, intense staining for K15 uniformly in the basal layer (as observed in foreskin epidermis in vivo) was observed only in the KSC/p7 DE culture (p). Many of the basal cells of the TA sheet weakly expressed K15 (q), while the differentiating cells were negative for K15 (r). Dotted line indicates the dermo-epidermal junction. Asterisks indicate K16-positive basal cells. Arrows indicate K15-positive basal cells. Scale bar: 50 μm.