C-Jun N-terminal kinase (JNK) pathway activation is essential for dental papilla cells polarization

During tooth development, dental papilla cells could develop into odontoblasts with polarized morphology and cell function, c-Jun N-terminal kinase (JNK) signaling could participate in this process. Histological staining, qPCR and Western Blot shown that activation of JNK signaling in polarized mouse dental papilla tissue. In vitro cell culture and organ culture method found JNK inhibitor SP600125 postponed tooth germ development and reduced the polarization, migration and differentiation of mouse dental papilla cells (mDPCs) in vitro. The expression of polarity-related genes including Prickle3, Golga2, Golga5 and RhoA was consistent with JNK signaling activation, by screening of up-regulated polarity-related genes during the process of dental papilla development and mDPCs or A11 differentiation. Further, constitutively active RhoA mutant (RhoA Q63L) partly rescue the inhibition of SP600125 on cell differentiation and polarity formation of mDPCs. This study suggests that JNK signaling has a positive role in dental papilla cells polarization formation.