ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effects of small interfering RNA (siRNA) targeting YAP on the proliferation and apoptosis of human periodontal ligament stem cells (hPDLSCs).</p><p><b>METHODS</b>Synthesized sequences of siRNA were transfected into hPDLSCs by Lipofectamine™ 2000. The expression of YAP was identified by using real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. Proliferation activity was detected by using cell counting kit-8 (CCK-8). Changes in the cell cycle and apoptosis rate were detected by using flow cytometry. Results were analyzed by using SPSS 19.0, and P < 0.05 was considered statistically significant.</p><p><b>RESULTS</b>Expression of YAP mRNA and protein were significantly downregulated after 48 h of transfection (P < 0.001). No obvious difference was found in the expression levels of YAP protein between 48 and 72 h, thus indicating that siRNA could inhibit the expression of YAP persistently and effectively. Proliferation activity was inhibited, and apoptosis rate was increased. Cell cycle was changed as the proportion of G₁and S phases increased (P < 0.01) and G₂ phase decreased (P < 0.05).</p><p><b>CONCLUSION</b>Knocking down YAP gene by siRNA could inhibit proliferation activity, induce apoptosis, and change the cell cycle of hPDLSCs. Thus, YAP could regulate the proliferation and apoptosis of hPDLSCs.</p>