Nicotinamide‐induced silencing of SIRT1 by miR‐22‐3p increases periodontal ligament stem cell proliferation and differentiation

Abstract

Dental stem cell proliferation and osteoblast differentiation are key cellular processes involved in periodontitis diseases. Researchers have found that SIRT1 (sirtuin 1, silent mating type information regulation 2 homolog 1) and microRNAs play a pivotal role in the process, but a clear underlying mechanism has not been determined. In this study, the has-miR-22-3p that target SIRT1 was predicted by TargetScan. Luciferase reporter assay was used to confirm that SIRT1 is the direct target of miR-22-3p. Importantly, miR-22-3p was revealed to control SIRT1 in periodontal ligament stem cell (PDLSC) and to regulate the proliferation and differentiation of PDLSC by SIRT1 silencing. Furthermore, we detected the induction of miR-22-3p expression by nicotinamide treatment on PDLSC. Induction of PDLSC proliferation and differentiation by nicotinamide treatment was blocked by miR-22-3p knockdown. These results suggested that the effect of nicotinamide on PDLSC is through miR-22-3p. In addition, miR-22-3p also upregulated the expression levels of the inflammatory cytokines tumor necrosis factor-α, interleukin-1β (IL-1β), and IL-8 in PDLSC through SIRT1 pathway and downregulated the expression of TLR-2 and TLR-4. miR-22-3p is a new target either for the treatment of periodontitis or the improvement of inflammation caused by orthodontics.