title: Effects of Fluoride on the Expression of Beclin1 and mTOR in Ameloblasts.
abstract: Exposure to high levels of fluoride (F-) can result in dental fluorosis in different individuals, but the mechanism of dental fluorosis remains unclear. Autophagy is a highly conserved intracellular digestion process that degrades damaged organelles and protein aggregates. This study examined the effect of sodium fluoride (NaF) on the expression of Beclin1 and mTOR to elucidate the development mechanisms of dental fluorosis. HAT-7 cells were incubated with various concentrations of NaF, and autophagic vacuoles were studied by transmission electron microscopy. At both mRNA and protein level, expression of Beclin1, which is required for autophagosome formation and decreases the expression of mTOR, an autophagy-related complex, was increased at 1.2 mmol/l NaF compared to baseline (0 mmol/l NaF). Additionally, immunohistochemical analysis was performed on paraffin-embedded rat incisor sections to identify the expression of Beclin1 and mTOR proteins in vitro. Highly significant differences were detected compared to controls. In summary, our results demonstrate unequivocally that excessive amounts of fluoride cause autophagy of HAT-7 cells, indicating that autophagy is involved in dental fluorosis.
authors.affiliation: Department of Preventive Dentistry, School of Stomatology, China Medical University, Shenyang, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Lei
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Kaiqiang
authors.initials: K
authors.lastname: Zhang
authors.forename: Jian
authors.initials: J
authors.lastname: Li
authors.forename: Lu
authors.initials: L
authors.lastname: Liu
mesh_terms: D000565:Ameloblasts / Q000187:drug effects*; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000032:analysis / Q000235:genetics*; D001343:Autophagy / Q000187:drug effects*; D000071186:Beclin-1; D002460:Cell Line; D005260:Female; D009050:Fluorosis, Dental / Q000209:etiology; D015870:Gene Expression / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics; D017208:Rats, Wistar; D012969:Sodium Fluoride / Q000494:pharmacology*; D058570:TOR Serine-Threonine Kinases / Q000032:analysis / Q000235:genetics*
chemical_list: D051017:Apoptosis Regulatory Proteins; D000071186:Beclin-1; C512829:Becn1 protein, rat; D012333:RNA, Messenger; D012969:Sodium Fluoride; D058570:TOR Serine-Threonine Kinases