miR-146a induces differentiation of periodontal ligament cells.

Differentiation of periodontal ligament (PDL) cells occurs under specific induction; furthermore, NF-kappaB signaling is important for regulation of bone differentiation. MicroRNAs are small non-coding RNAs that repress the translation of target genes and modulate cellular processes. miR-146a has been reported to modulate NF-kappaB signaling. This study hypothesized that miR-146a has a regulatory role in PDL differentiation by affecting NF-kappaB signaling. Immortalized PDL (I-PDL) cell lines were established by exogenous telomerase expression. The genesis of alkaline phosphatase and the up-regulation of miR-146a were induced by ascorbic acid in the I-PDL cells and primary PDL cells. I-PDL cells with exogenous miR-146a expression showed attenuation of NF-kappaB activity and exhibited higher differentiation relative to the controls. Exogenous NF-kappaB expression decreased the expression of differentiation markers, while the inactivation of endogenous NF-kappaB increased alkaline phosphatase in I-PDL cells. This study concludes that miR-146a promotes the differentiation in PDL cells through the down-regulation of NF-kappaB signaling.