Screening of differentially expressed miRNAs during osteogenic/odontogenic differentiation of human dental pulp stem cells exposed to mechanical stress

MicroRNAs (miRNAs) have been demonstrated as crucial transcriptional regulators in proliferation, differentiation, and tumorigenesis. The comprehensive miRNA profiles of osteogenic/odontogenic differentiation of human dental pulp stem cells (hDPSCs) under the condition of mechanical stress remains largely unknown. In this study, we aimed to discover the miRNA expression profiles of hDPSCs exposed to mechanical stress under the osteogenic/odontogenic process. We found that mechanical stress (0.09 MPa and 0.18 MPa, respectively, 30 min/ day) significantly promoted the proliferation of hDPSCs since the fifth day. The expressions of DSPP, DMP1, and RUNX2 were significantly increased on day 7 in the presence of 0.09 MPa and 0.18 MPa mechanical stress. On day 14, the expression levels of DSPP, DMP1, and RUNX2 were decreased in the presence of mechanical stress. Among 2578 expressed miRNAs, 5 miRNAs were upregulated and 3 miRNAs were downregulated. Six hub target genes were merged in protein-protein interactions (PPI) network analysis, in which existed only one sub-network. Bioinformatics analysis identified an array of affected signaling pathways involved in the development of epithelial and endothelial cells, cell-cell junction assembly, Rap1 signaling pathway, regulation of actin cytoskeleton, and MAPK signaling pathway. Our results revealed the miRNA expression profiles of osteogenic/odontogenic differentiation of hDPSCs under mechanical stress and identified eight miRNAs that were differentially expressed in response to the mechanical stress. Bioinformatics analysis also showed that various signaling pathways were affected by mechanical stress.