Fig. 6

Rescue of odontoblast differentiation in vitro and Atp6i^−/− tooth germ root formation in vivo with addition of TGF-β1. a qPCR result of the expression of odontoblast differentiation markers in pulp precursor cell line induced by Atp6i^−/− OC BRCM with addition of TGF-β1 for 7 days. WT BRCM, conditioned medium from WT osteoclast cultured with bone; Atp6i^−/− BRCM, conditioned medium from Atp6i^−/− osteoclast cultured with bone. Hprt was used as an endogenous control. n ≥ 6 in each group; *P < 0.05; **P < 0.01. b Schematic diagram of the kidney capsule transplantation system. Newborn tooth germs alone or with beads were transplanted underneath WT host mouse kidney capsule for in vivo rescue experiment. Red-dotted lines outlined crown of the first molar in the tooth germ. c–n Representative images of H&E staining of newborn WT and Atp6i^−/− tooth germs cultured under kidney capsules. Newborn WT (c–e) and Atp6i^−/− (f–h) tooth germs were transplanted alone under kidney capsules, or with 0.1% BSA beads (i–k) or TGF-β1 beads (l–n) for 3 weeks. Arrows indicated root formation in each sample. Red-dotted sections in (n) outlined radicular dentin. n = 7 tooth germs per each group