- Fluoride activates histone acetyltransferase (HAT) in enamel organ-derived LS8 cells.
- HAT inhibitors suppressed fluoride-mediated acetylation of p53 and cell toxicity.
- Modulation of HAT activity may be a potential target to mitigate fluoride toxicity.
Previously we demonstrated that fluoride increased acetylated-p53 (Ac-p53) in LS8 cells that are derived from mouse enamel organ epithelia and in rodent ameloblasts. However, how p53 is acetylated by fluoride and how the p53 upstream molecular pathway responds to fluoride is not well characterized. Here we demonstrate that fluoride activates histone acetyltransferases (HATs) including CBP, p300, PCAF and Tip60 to acetylate p53. HAT activity is regulated by post-translational modifications such as acetylation and phosphorylation. HAT proteins and their post-translational modifications (p300, Acetyl-p300, CBP, Acetyl-CBP, Tip60 and phospho-Tip60) were analyzed by Western blots. p53-HAT binding was detected by co-immunoprecipitation (co-IP). Cell growth inhibition was analyzed by MTT assays. LS8 cells were treated with NaF with/without HAT inhibitors MG149 (Tip60 inhibitor) and Anacardic Acid (AA; inhibits p300/CBP and PCAF). MG149 or AA was added 1 h prior to NaF treatment. Co-IP results showed that NaF increased p53-CBP binding and p53-PCAF binding. NaF increased active Acetyl-p300, Acetyl-CBP and phospho-Tip60 levels, suggesting that fluoride activates these HATs. Fluoride-induced phospho-Tip60 was decreased by MG149. MG149 or AA treatment reversed fluoride-induced cell growth inhibition at 24 h. MG149 or AA treatment decreased fluoride-induced p53 acetylation to inhibit caspase-3 cleavage, DNA damage marker YH2AX expression and cytochrome-c release into the cytosol. These results suggest that acetylation of p53 by HATs contributes, at least in part, to fluoride-induced toxicity in LS8 cells via cell growth inhibition, apoptosis, DNA damage and mitochondrial damage. Modulation of HAT activity may, therefore, be a potential therapeutic target to mitigate fluoride toxicity in ameloblasts.
*Original abstract online at https://www.sciencedirect.com/science/article/pii/S0045653520300163
*Funding of study at https://europepmc.org/article/MED/31927229
Fluoride affects enamel protein content via TGF-B1-mediated KLK4 inhibition
Dental fluorosis is caused by chronic high-level fluoride (F-) exposure during enamel development, and fluorosed enamel has a higher than normal protein content. Matrix metalloproteinase 20 cleaves enamel matrix proteins during the secretory stage, and KLK4 further cleaves these proteins during the maturation stage so that the proteins can be
Fluoride induced endoplasmic reticulum stress and calcium overload in ameloblasts
OBJECTIVE: The aim of the study was to evaluate the involvement of endoplasmic reticulum stress and intracellular calcium overload on the development of dental fluorosis. METHODS: We cultured and exposed rat ameloblast HAT-7 cells to various concentrations of fluoride and measured apoptosis with flow cytometry and intracellular Ca2+ changes using confocal
Fluoride Alters Signaling Pathways Associated with the Initiation of Dentin Mineralization in Enamel Fluorosis Susceptible Mice.
Fluoride can alter the formation of mineralized tissues, including enamel, dentin, and bone. Dentin fluorosis occurs in tandem with enamel fluorosis. However, the pathogenesis of dentin fluorosis and its mechanisms are poorly understood. In this study, we report the effects of fluoride on the initiation of dentin matrix formation and
Protective effect of lycopene on fluoride-induced ameloblasts apoptosis and dental fluorosis through oxidative stress-mediated Caspase pathways
Fluoride is an environmental toxicant and induces dental fluorosis and oxidative stress. Lycopene (LYC) is an effective antioxidant that is reported to attenuate fluoride toxicity. To determine the effects of LYC on sodium fluoride (NaF) -induced teeth and ameloblasts toxicity, rats were treated with NaF (10 mg/kg) and/or LYC (10 mg/kg) by
Fluoride Alters Klk4 Expression in Maturation Ameloblasts through Androgen and Progesterone Receptor Signaling.
Fluorosed maturation stage enamel is hypomineralized in part due to a delay in the removal of matrix proteins to inhibit final crystal growth. The delay in protein removal is likely related to reduced expression of kallikrein-related peptidase 4 (KLK4), resulting in a reduced matrix proteinase activity that found in fluorosed
Related Studies :
Mechanisms by Which Fluoride Causes Dental Fluorosis Remain Unknown
When it comes to how fluoride impacts human health, no tissue in the body has been studied more than the teeth. Yet, despite over 50 years of research, the mechanism by which fluoride causes dental fluorosis (a hypo-mineralization of the enamel that results in significant staining of the teeth) is not
Dental Fluorosis Is a "Hypo-mineralization" of Enamel
Teeth with fluorosis have an increase in porosity in the subsurface enamel ("hypomineralization"). The increased porosity of enamel found in fluorosis is a result of a fluoride-induced impairment in the clearance of proteins (amelogenins) from the developing teeth. Despite over 50 years of research, the exact mechanism by which fluoride impairs amelogin
Dental Fluorosis in the U.S. 1950-2004
Before the widespread use of fluoride in dentistry, dental fluorosis was rarely found in western countries. Today, with virtually every toothpaste now containing fluoride, and most U.S. water supplies containing fluoride chemicals, dental fluorosis rates have reached unprecedented levels. In the 1950s, it was estimated that only 10% of children in
"Mild" Dental Fluorosis: Perceptions & Psychological Impact
The vast majority of research has found that patients, parents, and the general public alike view mild fluorosis (TF score 3) as a significant blemish of the teeth, one that is likely to embarrass the affected child to a degree that cosmetic treatment would be warranted.
Diagnostic Criteria for Dental Fluorosis: The TSIF ("Total Surface Index of Fluorosis")
The traditional criteria (the "Dean Index") for diagnosing dental fluorosis was developed in the first half of the 20th century by H. Trendley Dean. While the Dean Index is still widely used in surveys of fluorosis -- including the CDC's national surveys of fluorosis in the United States -- dental
Related FAN Content :