miR-21 and miR-101 regulate PLAP-1 expression in periodontal ligament cells.

Periodontal ligament-associated protein-1 (PLAP-1/asporin) is a special marker in periodontal ligament tissue. It is an important regulator of osteogenic differentiation of periodontal ligament cells (PDLCs). This marker is also a prerequisite for periodontal ligament development and mineralization in maintaining homeostasis of the periodontium. However, the molecular mechanisms of the regulation of PLAP-1 expression at the post-transcriptional level remain unknown. By contrast, microRNAs (miRNAs) provide an additional level of regulation beyond that of transcription factors via regulation of the post-transcriptional control of gene expression. This study was designed to analyze miRNA differential expression patterns of PDLCs at various osteoblastic differentiation stages and to determine the contribution of miRNAs in the regulation of PLAP-1 expression during osteoblast differentiation. Bioinformatic analysis was performed to predict miRNAs that potentially regulate the gene expression of PLAP-1. Dual luciferase reporter assay and qRT-PCR were performed to confirm the effects of these miRNAs on PLAP-1 gene expression. Our results indicated that mir-101 and mir-21 target PLAP-1 to regulate its expression during osteogenic differentiation of PDLCs.