Inorganic phosphate regulates Glvr-1 and-2 expression: Role of calcium and ERK1/2

Sodium-dependent phosphate cotransporters are key regulators of phosphate homeostasis and play a major role in mineralized tissues remodelling. However, factors influencing their expression remain under consideration, In Our Study, modulation of type III sodium-dependent phosphate cotransporters expression by inorganic phosphate (Pi) was investigated in the murine odontoblast-like cell line MO6-G3. Experiments were designed to determine the effects of phosphate release on dental cells during tooth decay. By real-time RT-PCR we demonstrated that Glvr-1 and -2 expressions are Up-regulated by Pi. The increase in Glvr-1 and -2 expressions was correlated with ERK1/2 phosphorylation and calcium/phosphate crystals formation in Cultured wells. Using calcium-free culture conditions or the specific inhibitor of ERK phosphorylation (UO126), we demonstrated that Pi effects on GIvr-1 and -2 up-regulation require the presence of calcium and involve ERK signalling pathways. This Study contributes to give new insights in the control of Pi transport during carious diseases. (C) 2009 Elsevier Inc. All rights reserved.