CD8⁺ T lymphocytes enhance the anabolic effect of intermittent parathyroid hormone on cementoblasts

Root resorption is usually inflammatory in nature and has a tight link with immune system. Intermittent parathyroid hormone (iPTH) could promote cementum regeneration. The cross-talk of immune cells and cementoblasts may play an important role in the regeneration which stayed to be elucidated. In this study, a CD8⁺ T cells-OCCM-30 cells coculture system was established in vitro to investigate whether CD8⁺ T cells could enhance the anabolic effect of iPTH on cementoblasts and to find out the potential link of the effect with Wnt signal pathway. Determined by real-time PCR and Western Blot, we found an amplified cementogenesis in the OCCM-30 cells from coculture system, including increased mRNA and protein expression of Alp, Opn and Runx2, ALP activity and mineralization. We also found iPTH could increase the expression of Wnt10b in CD8⁺ T cells by ELISA. In addition, Wnt10b would promote the proliferation of OCCM-30 cells, while the effect on differentiation was various in different culture medium. These results demonstrated that the stimulating effect of iPTH on cementoblasts could be mediated through an interaction with CD8⁺ T cells, and T-cell-induced Wnt10b might be a key mechanism in the mediation.