Effects of prostaglandin E<inf>2</inf>on clonogenicity, proliferation and expression of pluripotent markers in human periodontal ligament cells

Abstract

© 2017 Elsevier Ltd Background and objective Based on our earlier work on the response of periodontal ligament (PDL) cells to mechanical stress by induction of cyclooxygenase expression and production of prostaglandin PGE2that could regulate mineralization of PDL cells, it was hypothesized that PGE2had potential effects on PDL stemness. In this study, we aimed to investigate clonogenicity, proliferation and expression of certain pluripotent markers, considered to be characteristics of PDL stemness, in response to treatment with exogenously-added PGE2. Material and methods Human PDL cells were cultured and treated with various doses of PGE2, and the aforementioned characteristics of PDL stemness were analyzed. Results The clonogenicity and proliferation were significantly enhanced by PGE2at low concentrations (0.01, 0.1 and 1 ng/ml; P < 0.05), but only the proliferation was significantly diminished by PGE2at a high concentration (100 ng/ml; P < 0.05). Expression of NANOG and OCT4 mRNA and protein was increased by PGE2treatment at 0.1 and 1 ng/ml. Consistently, expression of stage-specific embryonic antigen 4, a putative stem cell marker, was significantly augmented by PGE2treatment at 1 ng/ml (P < 0.05). Conclusion Our findings suggest that although a high dose of PGE2(100 ng/ml) inhibits proliferation of PDL cells, PGE2at low doses appears to play a role in the maintenance of PDL stemness.