LAUSR

OBJECTIVES Stem cells of the apical papilla (SCAPs) provide promising candidates for dental pulp regeneration. Despite great advances in the transcriptional controls of the SCAPs fate, little is known about the regulation of SCAP differentiation. MATERIALS AND METHODS Short hairpin RNAs and full-length RNA were used to deplete or overexpress lysine demethylase 4D (KDM4D) gene expression. Western blotting, real-time RT-PCR, alizarin red staining, and scratch migration assays were used to study the role of KDM4D and the ribosomal protein encoded by RPS5 in SCAPs. RNA microarray, chromatin Immunoprecipitation (ChIP) and co-immunoprecipitation (Co-IP) assays were performed to explore the underlying molecular mechanisms. RESULTS KDM4D enhanced the osteo/dentinogenic differentiation, migration, and chemotaxis of SCAPs. The microarray results revealed that 88 mRNAs (14 upregulated and 74 downregulated) were differentially expressed in KDM4D-overexpressed SCAPs. ChIP results showed knock-down of KDM4D increased the level of H3K9me2 and H3K9me3 in CNR1 promoter region. There were 37 possible binding partners of KDM4D. KDM4D was found to combine with RPS5, which also promoted the osteo/dentinogenic differentiation, migration, and chemotaxis of SCAPs. CONCLUSIONS KDM4D promoted the osteo/dentinogenic differentiation and migration potential of SCAPs in combination with RPS5, which provides a therapeutic clue for improving SCAPs-based dental tissue regeneration.