Effect of SHP2 knockdown on the proliferation and osteogenic differentiation of human periodontal ligament stem cells under inflammatory environment / 口腔疾病防治

ABSTRACT

Objective @# The purpose of this study was to clarify the regulatory effect and mechanism of Src homology-2 domain containing protein tyrosine phosphatase-2 (SHP2) on human periodontal ligament stem cell (hPDLSC) proliferation and osteogenic differentiation under inflammatory environment and to provide a new target for the treatment of periodontitis. @*Methods@#SHP2 was knocked down in hPDLSCs, and the transfection efficiency of SHP2 was detected by RT-qPCR and Western blot. An in vitro inflammatory environment was created using tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). The effect of SHP2 knockdown on hPDLSC viability under normal and inflammatory conditions was detected by CCK-8, and the osteogenic capacity of hPDLSCs under normal and inflammatory conditions was detected by ALP staining, ALP activity, ARS staining, RT-qPCR and Western blot. The mechanism by which SHP2 knockdown affected the MAPK pathway and its downstream NF-κB pathway under inflammatory conditions was assessed by Western blot. @*Results@# Green fluorescence was observed after transfection for 72 h, and the titer of SHP2 shRNA recombinant lentivirus was 2.9×108 TU/mL. SHP2 expression was significantly downregulated in lentivirus-transfected cells, as demonstrated by Western blot and RT-qPCR (P<0.001). SHP2 knockdown inhibited hPDLSC proliferation to a certain extent and increased the expression of early osteogenic markers under normal conditions, including increased ALP activity and increased ALP and COL-1 expression (P<0.05). However, SHP2 knockdown exerted no effect on mineralized nodule formation. In the TNF-α- and IL-1β-induced inflammatory environment, SHP2 knockdown exerted no effect on hPDLSC proliferation (P>0.05). Osteogenic markers were upregulated (P<0.05), and mineralized nodules were significantly increased (P<0.05) after SHP2 knockdown. Western blot analysis showed that p65 phosphorylation and IκB-α degradation were reduced in SHP2-knockdown hPDLSCs in the inflammatory environment. Moreover, SHP2 knockdown significantly inhibited the expression of p-p38 and p-JNK MAPK, which represent pathways upstream of the NF-κB pathway (P<0.05). @*Conclusion @# SHP2 knockdown did not affect cell viability but promoted the osteogenic potential of hPDLSCs by inhibiting the MAPK/NF-κB-mediated signaling pathway under inflammatory environment.