MicroRNA-135b inhibits odontoblast-like differentiation of human dental pulp cells by regulating Smad5 and Smad4.

AIM: To investigate the function of miRNAs in odontoblast-like differentiation of human dental pulp cells (hDPCs). METHODOLOGY: Integrated comparative miRNA microarray profiling was used to determine the differential miRNAs expression in odontoblast-like differentiation of hDPCs. The abundance of microRNA-135b (miR-135b) was measured by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH). Bioinformatic analyses combined with luciferase assays were utilized to identify the targets interacting with miR-135b. Overexpression of miR-135b was performed to investigate the role and mechanism in odontoblast-like differentiation of hDPCs. Statistical analysis was performed by one-way analysis of variance (anova) or Student's t-test. RESULTS: Thirty-six differentially expressed microRNAs in odontoblast-like differentiation of hDPCs were identified. MiR-135b expression was significantly downregulated during hDPCs differentiation (P < 0.05). In addition, miR-135b was able to bind to the 3'-UTR of the Smad5 and Smad4 and repressed these two genes expression (P < 0.05). Furthermore, overexpression of miR-135b suppressed odontoblast-like differentiation of hDPCs and attenuated the expression of Smad5 and Smad4 (P < 0.05). CONCLUSIONS: These observations indicated a potential role of miR-135b in mediating odontoblast-like differentiation of hDPCs and inhibition of miR-135b might be a promising therapeutic way to facilitate dentine tissue engineering.