Sodium fluoride‐induced autophagy of ameloblast‐like cells via the p‐ULk1/ATG13/LC3B pathway in vitro

Abstract Objective To investigate the effects of sodium fluoride on the ameloblast and reveal the mechanism of dental fluorosis. Materials and methods Mouse ameloblast‐like cell line (ALC) cells were treated with various concentrations of NaF, and subjected to Incucyte, fluorescence immunoassay, transmission electron microscopy, reverse transcription quantitative polymerase chain reaction (RT‐qPCR), western blot for autophagy examination, alkaline phosphatase and alizarin red staining for mineralization after osteogenic induction. Results NaF exerts a dose‐dependent inhibitory effect on ALC cell growth. TEM and fluorescence immunoassay showed that 1.5 mM or higher concentrations of NaF could induce a fusion of lysosome and mitochondria, finally increasing the number of autophagosome. RT‐qPCR and western blot showed that the upregulation of autophagy related gene 13 (ATG13), downregulation of phosphorylated Unc‐51‐like kinase 1 (p‐ULK1) were found in NaF‐induced autophagy of ALC cells. The knockdown of ATG13 could rescue it as well as the expression of p‐ULK1 and LC3B. Besides, alizarin red staining showed that fluoride under these concentrations could promote the mineralization of ALC. Conclusions The data show that fluoride in higher concentration can induce autophagy via the p‐ULk1/ATG13/LC3B pathway of ALCs than lower ones promote mineralization in vitro, which provides insight into the function of NaF in the autophagy and mineralization of ameloblast.