MicroRNA-22 Promoted Osteogenic Differentiation of Human Periodontal Ligament Stem Cells by Targeting HDAC6.

Stem cells transplantation is a promising therapy strategy for accelerating periodontal regeneration and reconstruction. Genetic modification could induce stem cells directional differentiation to facilitate recovery of physiological functions. In this study, we investigated the role and mechanism of miR-22 on human periodontal ligament stem cells (PDLSCs). First, a cellular model of osteogenic differentiation was first established by osteogenic inductive cocktail. Real-time PCR determined that expression of miR-22 was significantly increased during PDLSCs osteogenic differentiation. Alizirin red staining showed that overexpression of miR-22 in PDLSCs induced better mineralized nodule formation. Real-time PCR and Western blot further confirmed up-regulation of osteogenic genes Runx2 and OPN in miR-22-overexpressing PDLSCs. Conversely, inhibition of miR-22 delayed the process of PDLSCs osteogenic differentiation. Furthermore, Histone deacetylase 6 (HDAC6) was identified as a target gene of miR-22. Overexpression of miR-22 not only reduced the luciferase activity of the reporter containing the 3' untranslated region of HDAC6 mRNA, but also suppressed the endogenous protein expression of HDAC6. Rescue experiment showed that the promotion role of miR-22 in osteogenic differentiation could be relieved by overexpression of HDAC6. Meanwhile, overexpression of HDAC6 alone could also delay the osteogenic differentiation process. The results demonstrated that miR-22 promoted PDLSCs osteogenic differentiation by inhibiting HDAC6 expression, suggesting that miR-22 might be developed as a target of genetic modified stem cells therapy for periodontal diseases. J. Cell. Biochem. 118: 1653-1658, 2017.