IL-6 regulates stress-induced REX-1 expression via ATP-P2Y1 signalling in stem cells isolated from human exfoliated deciduous teeth

Objective: To investigate the relationship between ATP and IL-6 in mechanical stress-induced REX-1 expression in SHEDs. Methods: Cells were stimulated with mechanical stress (0-2.5 g cm(-2)), IL-6 (0.1-5 ng/ml), or ATP (10-100 mu M) for 2 h in serum-free media. IL-6 and REX-1 expression was examined by qualitative and quantitative polymerase chain reaction. ATP release was measured using a bioluminescence assay. The molecular mechanisms of the signalling pathways were investigated using chemical inhibitors. Results: Mechanical stress induced IL-6 and REX-1 mRNA expression and ATP release. JAK inhibitor I inhibited the increase in REX-1 expression and ATP release but not IL-6 induction. Furthermore, suramin inhibited the upregulation of REX-1 mRNA expression but not ATP release. Exogenous IL-6 promoted both ATP release and REX-1 expression. The IL-6-induced REX-1 expression was attenuated by a P2Y1-specific receptor antagonist. Moreover, REX-1 expression was upregulated in a dose-dependent manner by the addition of ATP or a P2Y1 agonist. This inductive effect was abolished by the P2Y1-specific receptor antagonist. Conclusions: ATP-P2Y1 signalling is involved in IL-6-regulated stress-induced REX-1 expression in SHEDs. These results imply the participation of mechanical stress, IL-6, and ATP in regulating the expression of REX-1, a pluripotent stem cell marker. (C) 2014 Elsevier Ltd. All rights reserved.