Transforming growth factor-beta-induced gene product-h3 inhibits odontoblastic differentiation of dental pulp cells

Objective: The aim of this study was to investigate transforming growth factor-b-induced gene producth3 (big-h3) expression in dental pulp tissue and its effects on odontoblastic differentiation of dental pulp cells (DPCs). Design: A rat direct pulp capping model was prepared using perforated rat upper first molars capped with mineral trioxide aggregate cement. Human DPCs (HDPCs) were isolated from extracted teeth. big-h3 expression in rat dental pulp tissue and HDPCs was assessed by immunostaining. Mineralization of HDPCs was assessed by Alizarin red-S staining. Odontoblast-related gene expression in HDPCs was analyzed by quantitative RT-PCR. Results: Expression of big-h3 was detected in rat dental pulp tissue, and attenuated by direct pulp capping, while expression of interleukin-1b and tumor necrosis factor-a was increased in exposed pulp tissue. big-h3 expression was also detected in HDPCs, with reduced expression during odontoblastic differentiation. The above cytokines reduced big-h3 expression in HDPCs, and promoted their mineralization. Recombinant big-h3 inhibited the expression of odontoblast-related genes and mineralization of HDPCs, while knockdown of big-h3 gene expression promoted the expression of odontoblast-related genes in HDPCs. Conclusions: The present findings suggest that big-h3 in DPCs may be involved in reparative dentin formation and that its expression is likely to negatively regulate this process