AEG-1 participates in the production of pro-inflammatory cytokines in dental pulp cells via NF-κB signaling pathway

Abstract

Aim

To identify the role of astrocyte elevated gene-1 (AEG-1) and the mechanism underlying the inflammatory response in dental pulp cells.

Methodology

AEG-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 signaling 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 signaling before the addition of LPS. Data were statistically analysed by one-way ANOVA.

Results

The 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 was 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.

Conclusion

AEG-1 participated in inflammatory cytokine synthesis via NF-κB signaling in dental pulp. Both NF-κB and PI-3K signaling are involved in LPS-induced AEG-1 expression in dental pulp cells.

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