Abstract
BACKGROUND: Circular RNAs (circRNAs) play a crucial role in stem cell-based tooth regeneration. However, the functions and underlying mechanisms of circRNAs in tooth regeneration from human dental pulp stem cells (DPSCs) remain largely unclear. METHODS: In this study, DPSCs were used for odontogenic differentiation. High-throughput sequencing was performed for differential circRNA analysis. A luciferase reporter assay was conducted to confirm the downstream target of the circRNA, circ-AARS. We then constructed vectors and siRNAs for overexpressing and silencing circ-AARS, miR-24-3p, and Krüppel-like factor 6 (KLF6) and transfected them into DPSCs. Alkaline phosphatase staining, Alizarin Red S staining, western blotting assay, and quantitative reverse transcription-polymerase chain reaction were used to explore the underlying mechanisms of circ-AARS. Finally, a heterotopic bone model was utilized to reveal the regulating effects of circ-AARS. RESULTS: High-throughput sequencing analysis showed that circ-AARS plays an important role during the odontogenic differentiation of DPSCs. Downregulation of circ-AARS inhibited the odontogenic differentiation of DPSCs; however, circ-AARS overexpression promoted their odontogenic differentiation. Bioinformatics analysis and luciferase reporter assay confirmed that both miR-24-3p and KLF6 were the downstream targets of circ-AARS. miR-24-3p downregulation or KLF6 overexpression restored the odontogenic differentiation ability of DPSCs after circ-AARS silencing. KLF6 upregulation restored the odontogenic differentiation ability of DPSCs after KLF6 overexpression. The heterotopic bone model confirmed that circ-AARS overexpression promoted the odontoblastic differentiation of DPSCs. CONCLUSION: The present study showed that circ-AARS can promote the odontoblastic differentiation of DPSCs by increasing KLF6 expression and sponging miR-24-3p. Taken together, the results indicate that circ-AARS may be a potential positive regulator of odontoblastic differentiation of DPSCs.