High-throughput sequencing analysis of the expression profile of microRNAs and target genes in mechanical force-induced osteoblastic/cementoblastic differentiation of human periodontal ligament cells.

Mechanical tension force directs the lineage commitment of periodontal ligament cells (PDLCs) to osteogenesis; however, the underlying mechanisms, especially those at the post-transcriptional level, remain unclear. In the present study, we developed an in vitro force-loading model for PDLCs. Then, high-throughput sequencing was used to identify the expression profile of microRNAs (miRNAs) for stretched PDLCs. The candidate target genes of differentially expressed miRNAs were predicted by bioinformatics analysis. A total of 47 miRNAs were found to be differentially expressed in stretched and non-stretched PDLCs; of these, 31 were upregulated and 16 were downregulated. Further, 9 osteogenesis-related miRNAs (miR-221-3p, miR-138-5p, miR-132-3p, miR-218-5p, miR-133a-3p, miR-145-3p, miR-143-5p, miR-486-3p, and miR-21-3p) were validated by quantitative reverse transcription-polymerase chain reaction (RT-qPCR). Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway analysis were then carried out to reveal the potential functions of predicted target genes. Among the top 20 enriched pathways, the Hippo signaling pathway was selected for further functional analysis. Several important components of the Hippo signaling pathway, including YAP1, WWTR1, TEAD2, CTGF, DVL2, GDF5, GLI2, LIMD1, WTIP, LATS1, and TEAD1, were predicted to be target genes of differentially expressed miRNAs and were determined to be upregulated in stretched PDLCs. Among them, YAP1, WWTR1, TEAD2, CTGF, DVL2, and GDF5 were positive regulators of osteogenesis. These findings may provide a reliable reference for future studies to elucidate the biological mechanisms of orthodontic tooth movement (OTM).