[SiRNA silencing Rsk2 gene expression inhibits proliferation and osteogenic differentiation of human periodontal ligament cells].

Purpose: To study the effect of ribosomal S6 kinase (Rsk2) gene on proliferation and osteogenic differentiation of human periodontal ligament cells (hPDLCs) and underlying mechanism.
Methods: Premolar surgically extracted were collected, the periodontal ligament was separated and hPDLCs were primarily cultured. Cells of 4 to 6 passage were used in the experiment. The silencing efficiency of small interfering RNA (siRNA) on Rsk2 in hPDLCs was detected by RT-PCR and Western blot. MTT assay was used to detect the effect of Rsk2 siRNA on cell proliferation. Alkaline phosphatase (ALP) kit was used to detect ALP activity. P38MAPK signal pathway inhibitor SB203580 was used to detect hPDLCs after transfection. Western blot was used to detect the effect of Rsk2 siRNA on MAPK signaling pathway p38 protein phosphorylation. The expressions of Runt-related transcription factor-2 (Runx2), osteocalcin (OCN) and osteogenic protein BMP2 were detected by RT-PCR and Western blot. The data were analyzed using SPSS18.0 software package.
Results: The expression of Rsk2 was down-regulated by hPDLCs transfected with Rsk2 siRNA, the difference was statistically significant (P<0.05). Rsk2 siRNA significantly reduced phosphorylation of p38 protein (P<0.05), inhibition of hPDLCs proliferation (P<0.05), decreased ALP activity (P<0.01); the expression of Runx2, OCN and BMP2 was different, and the difference was statistically significant (P<0.05). After SB203580 treatment, hPDLCs transfected with Rsk2 siRNA showed increased cell proliferation, ALP activity, Runx2, OCN and BMP2 expression; compared with Rsk2 siRNA transfected hPDLCs, the difference was statistically significant.
Conclusions: Rsk2 siRNA inhibits hPDLCs proliferation and osteogenic differentiation through p38MAPK signaling pathway.