FoxO3a Regulates Inflammation-induced Autophagy In Odontoblasts

Objective:Odontoblasts constitute an important barrier to cariogenic bacterial infection.The survival of these cells is significant for the prognosis of inflamed pulp.Fox03a is a member of FoxO transcription factor family that participates in the transcriptional regulation of autophagy.However,the regulatory mechanisms of autophagy induced by inflammation in odontoblasts are not clear.In this study,we explored the anti-inflammatory function of Fox03a regulated autophagy in inflamed human dental pulp and LPS-treated mDPC6T cells.Methods:We collected human malpositioned third teeth and healthy teeth extracted for orthodontics and divided them into healthy group,carious group and pulpitis group according to the pulp condtion.The expression region and levels of Fox03a and autophagy markers in human dental pulp were examined by immunohistochemistry and western blot.Then in vitro studies,we treated mDPC6T cells with lipopolysaccharide for various lengths of time.Next,we measured the nuclear translocation of Fox03a and the colocalization of Fox03a and LC3 by immunofluorescence.Moreover,we decreased Fox03a level using siRNA to investigate the potential relationship between Fox03a and autophagy.Results:The expression of Fox03a and autophagy proteins(Atg5-Atg12?Beclinl?LC3)were upregulated in the odontoblasts of human caries and pulpitis samples.Additionally,we also observed that the increased expressions of Fox03a in cytoplasm and nuclear of odontoblasts was positively correlated with the progression of inflammation(TNFa indicated).The result of our in vitro study revealed that LPS treatment increased nuclear translocation of Fox03a and activated autophagy(Atg5-Atg12?Beclinl?LC3 expression indicated)in mDPC6T cells in the early stage.And the increased colocalizatin of Fox03a and LC3 was detected within 12h LPS treatment(yellow dots).We also observed that the knockdown of Fox03a suppressed autophagy.Conclusions:Our data indicates that Fox03a might play a role in maintenance of intracellular homeostasis of inflamed odontoblasts by avtivated autophagy.