Expression of matrix extracellular phosphoglycoprotein in human dental pulp cells undergoing odontoblastic differentiation

Abstract

To investigate the expression of matrix extracellular phosphorylated protein (MEPE) in human dental pulp cells (hDPC) undergoing odontogenic induction and explore the role of MEPE in odontoblast-like differentiation. hDPC were isolated by enzymatic digestion and preceded to odontogenic induction for 7, 14 and 21 days respectively. hDPC before induction served as controls. The expressions of MEPE, dentin sialophosphoprotein (DSPP)/dentin sialoprotein (DSP), bone sialoprotein (BSP) and collagen type I were determined by quantitative real-time RT-PCR and Western blotting. The mRNA levels of MEPE, DSPP, BSP and type I collagen were increased in a time-dependent manner as hDPC were induced along odontoblastic lineage. Statistical differences were detected for MEPE and BSP mRNA expressions in induced hDPC compared with control group (P < 0.001). For DSPP and type I collagen, the mRNA levels in the induced groups were (12 943.33 + or - 3805.73) and (250.55 + or - 31.86) respectively, which were significantly higher than those in control group on days 21 (P < 0.05). Western blotting also revealed the increased expressions of MEPE, DSP, BSP and type I collagen in the induced DPC. hDPC showed analogously temporal expressions of MEPE, DSPP/DSP, BSP and collagen type I while differentiating along odontoblast lineage. MEPE may play an important role in the odontogenic differentiation of hDPC and may be a potential marker of odontoblast-like differentiation.