The Expression of Periostin in Dental Pulp Cells

Abstract

Abstract

Introduction: The proper regulation of the dentin-pulp complex is intimately related through crucial cell-matrix interactions and important bioactive proteins. The proteins modulating these interactions are highly expressed during development and implicated in tissue repair and regeneration. Within this context, periostin is essential for ECM stability, collagen fibrillogenesis, and tissue healing. Periostin is regulated by TGF-β1 in response to biomechanical challenges in the PDL. In the scope of the dental pulp, periostin expression is reported during development and active dentinogenesis, but has yet to be evaluated in dental pulp cells specifically. We hypothesize that periostin is expressed by DPCs in response to TGF-β1 and biomechanical stimulation, which has implications in dental pulp tissue healing and regeneration. Aims: 1) To determine if periostin is expressed by DPCs and to analyze the effect in response to TGF-β1 2) To analyze the influence of biomechanical stimulation on the expression of periostin in DPCs, 3) To analyze the influence of periostin on the expression of collagen in DPCs.

Methods: Human dental pulp stem cells (DPSC), human dental pulp fibroblasts (DPF), and murine odontoblast-like cells (MDPC-23) were treated with different concentrations of TGF-β1 or different regimens of biomechanical stimulation to evaluate periostin expression. Cells were also treated with periostin to evaluate the effect on collagen. Western blot and ELISA were used to evaluate protein expression. RNA analysis was performed by qRT-PCR and a Total Collagen Assay was utilized to evaluate collagen. Statistical analysis was performed by Student T-test and ANOVA with Fisher’s LSD test.

Results: Each cell line expressed periostin protein and mRNA. TGF-β1 supplementation resulted in significant changes of periostin expression. Biomechanical stimulation acts to induce changes in periostin expression. No statistically significant differences were found in total collagen expression. Conclusions: Expression of periostin was identified in each of the dental pulp cell lines, which can be regulated by TGF-β1. DPSC are the most responsive cells to stimulation. Continued research and evaluation is needed to determine the potential therapeutic ability of periostin within the dental pulp.