Effect of Prostaglandin E₂ on Human Dental Follicle Cells during Osteogenic Differentiation

Abstract

　Stem/progenitor cells isolated from human dental follicles differentiate into osteogenic cells. To investigate factors associated with osteogenic differentiation/mineralization in human dental follicle cells (hDFCs), we performed gene expression profiling of hDFCs during osteogenic differentiation. Cyclooxygenase (COX)-1 and -2 were up-regulated in hDFCs cultured in osteogenic induction medium(OIM)compared to growth medium (GM). Prostaglandin E₂ (PGE₂), which is the most studied prostanoid derived from arachidonic acid through the actions of COXs, may regulate bone metabolism. All PGE₂ E-type prostanoid receptors (EP), EP1-EP4, were expressed in hDFCs. Real-time PCR showed that the expression of EP2 and EP4 was increased in hDFCs cultured in OIM and GM at days 10 and 17 compared to day 0. We investigated the action of PGE₂ in osteogenic differentiation using hDFCs. PGE₂ decreased gene expression levels of osterix and alkaline phosphatase, which are factors associated with osteogenic differentiation. PGE₂ elicited inhibitory action on matrix mineralization of hDFCs as seen with alizarin red S staining. These findings suggest that PGE₂ may inhibit osteogenic differentiation/mineralization of stem/progenitor cells.