Shu Diao1, Dong-Mei Yang1, Rui Dong2, Li-Ping Wang2, Jin-Song Wang3, Juan Du4, Song-Lin Wang3, Zhipeng Fan5. 1. Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, China; Department of Pediatric Dentistry, Capital Medical University School of Stomatology, Beijing, China. 2. Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, China. 3. Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, China; Department of Biochemistry and Molecular Biology, Capital Medical University School of Basic Medical Sciences, Beijing, China. 4. Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, China; Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, China. 5. Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, China. Electronic address: zpfan@ccmu.edu.cn.
Abstract
INTRODUCTION: Dental tissue-derived mesenchymal stem cells (MSCs) are a reliable cell source for dental tissue regeneration. However, the molecular mechanisms underlying their directed differentiation remain unclear, thus limiting their use. Trimethylation of lysine 4 of histone H3 (H3K4Me3) correlates with gene activation and osteogenic differentiation. We used stem cells from apical papilla (SCAPs) to investigate the effects of genomic changes in H3K4Me3 modification at gene promoter regions on MSC osteogenic differentiation. METHODS: ChIP-on-chip assays were applied to compare the H3K4Me3 profiles at gene promoter regions of undifferentiated and differentiated SCAPs. Alkaline phosphatase activity assay, alizarin red staining, quantitative analysis of calcium, the expressions of osteogenesis-related genes, and transplantation in nude mice were used to investigate the osteogenic differentiation potentials of SCAPs. RESULTS: In differentiated SCAPs, 119 gene promoters exhibited >2-fold increases of H3K4Me3; in contrast, the promoter regions of 21 genes exhibited >2-fold decreases of H3K4Me3. On the basis of enriched H3K4Me3 and up-regulated gene expression on the osteogenic differentiation of SCAPs, WDR63 may be a potential regulator for mediating SCAP osteogenic differentiation. Through gain-of-function and loss-of-function studies, we discovered that WDR63 enhances alkaline phosphatase activity, mineralization, and the expression of BSP, OSX, and RUNX2 in vitro. In addition, transplant experiments in nude mice confirmed that SCAP osteogenesis is triggered by activated WDR63. CONCLUSIONS: These results indicate that WDR63 is a positive enhancer for SCAP osteogenic differentiation and suggest that activation of WDR63 signaling might improve tissue regeneration mediated by MSCs of dental origin.
INTRODUCTION: Dental tissue-derived mesenchymal stem cells (MSCs) are a reliable cell source for dental tissue regeneration. However, the molecular mechanisms underlying their directed differentiation remain unclear, thus limiting their use. Trimethylation of lysine 4 of histone H3 (H3K4Me3) correlates with gene activation and osteogenic differentiation. We used stem cells from apical papilla (SCAPs) to investigate the effects of genomic changes in H3K4Me3 modification at gene promoter regions on MSC osteogenic differentiation. METHODS: ChIP-on-chip assays were applied to compare the H3K4Me3 profiles at gene promoter regions of undifferentiated and differentiated SCAPs. Alkaline phosphatase activity assay, alizarin red staining, quantitative analysis of calcium, the expressions of osteogenesis-related genes, and transplantation in nude mice were used to investigate the osteogenic differentiation potentials of SCAPs. RESULTS: In differentiated SCAPs, 119 gene promoters exhibited >2-fold increases of H3K4Me3; in contrast, the promoter regions of 21 genes exhibited >2-fold decreases of H3K4Me3. On the basis of enriched H3K4Me3 and up-regulated gene expression on the osteogenic differentiation of SCAPs, WDR63 may be a potential regulator for mediating SCAP osteogenic differentiation. Through gain-of-function and loss-of-function studies, we discovered that WDR63 enhances alkaline phosphatase activity, mineralization, and the expression of BSP, OSX, and RUNX2 in vitro. In addition, transplant experiments in nude mice confirmed that SCAP osteogenesis is triggered by activated WDR63. CONCLUSIONS: These results indicate that WDR63 is a positive enhancer for SCAP osteogenic differentiation and suggest that activation of WDR63 signaling might improve tissue regeneration mediated by MSCs of dental origin.