Osteopontin Facilitated Dental Pulp Cell Adhesion and Differentiation: A Laboratory Investigation.

AIM

To investigate the effects of osteopontin (OPN) on cultured human dental pulp cells (hDPCs) in relation to adhesion, proliferation, differentiation, and mineralization.

METHODOLOGY

Subcultured hDPCs isolated from healthy human wisdom teeth were inoculated on noncoated (NC, control) and OPN-coated nontissue culture-treated polystyrene plates (Non-TCPS). Cell adhesion and proliferation were analyzed by crystal violet staining and the CCK-8 assay, respectively. Expressions of cell adhesion-related protein markers such as FAK and Akt were visualized by the Western blot. Expressions of tooth-related mRNA markers were evaluated by qRT-PCR. The localization of the OPN protein in reparative dentine formation was visualized using immunofluorescence staining. Data were analyzed using the Tukey's multiple comparison test.

RESULTS

Cell adhesion was significantly higher in OPN 1 μg/mL-coated group of the OPN, which is also comparable to that of the positive control (COL-1 group). Cell proliferation data showed a similar tendency. pFAK was activated as early as 3 h after cell inoculation in the 1 μg/mL-coated group of the OPN and COL-1 group. Moreover, the OPN stimulated hDPC mineralization in a time- and dose-dependent manner. Regarding the qPCR results, it was shown that OPN stimulated DMP-1 and expression on days 10 and 14. The RNA sequencing data implicated that the OPN promoted the gene expression of HLA-DRA, CD74, ENSG00000283390, MRPL53, NOP2, and KRTAP1-3. Finally, pulp exposure wound healing in SD rats showed that OPN expression was primarily localized in the forming reparative dentine instead of formed reparative dentine.

CONCLUSION

Coated OPN promoted hDPC adhesion, proliferation, differentiation, and mineralization.