Astrocyte elevated gene‐1 participates in the production of pro‐inflammatory cytokines in dental pulp cells via NF‐κB signalling pathway

• DOI: 10.1111/iej.12921
• Publication Date: 2018-03-05T16:52:39Z
• Authors: H. Wu; M. He; R. Yang; Y. Zuo; Z. Bian
• Keywords: Inflammation; Lipopolysaccharides; 0301 basic medicine; NF-kappa B; Membrane Proteins; Pulpitis; RNA-Binding Proteins; 16. Peace & justice; Rats; Up-Regulation; Phosphatidylinositol 3-Kinases; 03 medical and health sciences; Gene Expression Regulation; Astrocytes; Models, Animal; Animals; Cytokines; RNA, Messenger; Cell Adhesion Molecules; Dental Pulp; Phosphoinositide-3 Kinase Inhibitors; Signal Transduction

AbstractAimTo identify the role of astrocyte elevated gene‐1 (AEG‐1) and the mechanism underlying the inflammatory response in dental pulp cells.MethodologyAstrocyte elevated gene‐1 expression was detected at different stages of pulpitis in a rat model using immunohistochemistry. RT‐qPCR and Western blot were used to assess AEG‐1 expression in human dental pulp cells stimulated by lipopolysaccharide (LPS). The LPS‐induced expression of inflammatory cytokine genes was quantified by RT‐qPCR in cells transfected with AEG‐1 or negative control (NC) siRNA. Immunofluorescence and Western blot were utilized to evaluate the activation of NF‐κB signalling in AEG‐1 knockdown cells. AEG‐1 expression was also investigated by Western blot in dental pulp cells pre‐treated with inhibitors of NF‐κB and PI‐3K signalling before the addition of LPS. Data were analysed statistically using one‐way anova.ResultsThe exposure of dental pulp tissue to LPS resulted in acute inflammation with necrosis and AEG‐1 expression in the pulp tissue beneath the perforation. In LPS‐stimulated dental pulp cells, AEG‐1 mRNA and protein were significantly up‐regulated (P < 0 .05) in a time‐ and dose‐dependent manner. In AEG‐1 knockdown cells, the synthesis of IL‐1, IL‐6 and TNF‐α mRNA was suppressed significantly (P < 0.05) upon LPS induction. AEG‐1 knockdown also inhibited nuclear translocation of p65. Suppression of NF‐κB and PI‐3K abrogated the LPS‐induced up‐regulation of AEG‐1.ConclusionAstrocyte elevated gene‐1 participated in inflammatory cytokine synthesis via NF‐κB signalling in the dental pulp. Both NF‐κB and PI‐3K signalling are involved in LPS‐induced AEG‐1 expression in dental pulp cells.