Fig. 4

Histogenesis of hKSC-derived dental epithelium in human–mouse chimeric teeth. Sections through chimeric teeth retrieved from subrenal culture at different time points processed with hematoxylin and eosin (A–C) or Azan dichromic staining that stains dentin (d) blue and enamel (e) red (D–H). a hKSC-derived epithelial bud (de) formed after 5 days in subrenal culture. B–E Tooth buds underwent typical dental epithelial histogenesis, forming the cap-like structure at day 6 (B), the bell-like structure at day 7 (C), elongated preameloblasts at day 8 (D), and well-differentiated ameloblasts (am) at day 9 (E), respectively, after subrenal culture. F hKSC-derived ameloblasts began to deposit enamel (e) on the surface of dentin (d) around day 12 after subrenal culture. G Thick layer of enamel secreted from hKSC-derived ameloblasts at around day 15 after subrenal culture. H Reduced thickness and compacted layer of enamel found in a graft cultured for 28 days. I A lateral (left) and top (right) view of human-mouse chimeric tooth crowns formed after 30 days in subrenal culture. J hKSC-derived ameloblasts expressed human SP6 but not GFP , and the odontoblasts and dental pulp cells of eGFP-mouse origin expressed GFP in human-mouse chimeric tooth crown after 8 days culture. stain Scale bar = 100µm (A-H, J), 500µm (I). 5d 5 days, dm dental mesenchyme, dp dental pulp, GFP green fluorescent protein