TAS2R supports odontoblastic differentiation of human dental pulp stem cells in the inflammatory microenvironment

BACKGROUND: Inflammatory microenvironment promotes odontoblastic differentiation in human dental pulp stem cells (hDPSCs), but the regulatory mechanisms remain unclear. In this study, we aimed to explore the role of TAS2R in odontoblastic differentiation of hDPSCs in the inflammatory microenvironment. METHODS: Microarray analysis was performed to explore the differential mRNA profiles in inflammatory and healthy pulp tissues from the patients. hDPSCs isolated from the healthy pulp tissues were stimulated by LPS, TNFα and IL-6, respectively, to verify the effect of TAS2R. The expression markers related to odontoblastic differentiation of hDPSCs were observed by qPCR and chemical staining methods. TAS2R10 was overexpressed or silenced to observe the effect on odontoblastic differentiation of hDPSCs under LPS stimulation. The G protein and intracellular Ca(2+) were detected, respectively, by qPCR and Fluo-4AM Ca(2+) fluorescent probe. RESULTS: The expression of TAS2R was significantly upregulated in the inflammatory pulp tissues. In vitro, 5 subtypes of TAS2R mRNA expressions including TAS2R10, TAS2R14, TAS2R19, TAS2R30 and TAS2R31 in hDPSCs increased under the stimulation of LPS, TNFα or IL-6. In odontoblastic differentiation medium, we found LPS, TNFα or IL-6 stimulation promoted odontoblastic differentiation of hDPSCs. TAS2R10 overexpression in hDPSCs significantly increased the expression markers related to odontoblastic differentiation, whereas TAS2R10 silencing revealed the opposite effect. Furthermore, G protein was activated, and at the same time, intracellular Ca(2+) enhanced when TAS2R10 was overexpressed, but decreased when TAS2R10 was silenced. CONCLUSIONS: This study demonstrated that TAS2R was found to be expressed in hDPSCs, and TAS2R promoted odontoblastic differentiation of hDPSCs by mediating the increase in intracellular Ca(2+) via the G protein-coupled receptors (GPCR) conventional signaling pathway in inflammatory microenvironment, which may be a potential target for the development of effective conservative treatments for dental pulp repair.