IADR Abstract Archives
Fluoridated Substrate on Acquired Enamel Pellicle: Quantitative Proteomic Analysis
The acquire enamel pellicle (AEP) is formed by the selective adsorption of salivary proteins onto the enamel. Fluoride in/on the enamel surface may modulate the AEP proteome and, thereafter, the AEP functions. Objective: This study aimed to investigate the effect of fluoride on the AEP proteome. In addition, this study pioneered the use of label-free quantitative proteomics to better understand the composition and function of AEP proteins. Method: Hydroxyapatite (G1), hydroxyapatite pre-treated with 5%NaF (G2) and fluorapatite discs (G3) were set as substrate for AEP development. Each group (n=6) was incubated with parotid secretion (100µg) for 2h, at 37°C, in order to mimic in vivo AEP formation. Pellicle proteins were eluted from the discs by their sonication with 50mM ammonium bicarbonate, pH 7.8. AEP samples were trypisinized and subjected to LC-ESI-MS/MS. In addition, the obtained MS/MS spectra were searched against human protein databases. Mass spectrometric data were validated by SDS-PAGE and Western-Blot analysis. Moreover, the surfaces were analyzed for wettability and elemental composition (X-ray photoelectron spectroscopy). Result: This novel survey lead to the identification of 39 AEP proteins in G1, 33 in G2 and 52 in G3. The most abundant proteins present in all groups included amylase, histatin1, acidic PRP1 and lysozyme. Relative proteomic quantification was carried out for the 17 proteins observed in all three groups. Interestingly, 15, 9 and 27 proteins exclusively identified in G1, G2 and G3, respectively, were associated with distinctive molecular functions. Conclusion: Fluoride in/on the substrate qualitatively and quantitatively modulates AEP formation, effects which in turn will likely impact the formation of oral biofilms. These results present novel insights into the architecture of the AEP following fluoride treatment. Support CIHR grant# 106657, grant# 97577 and grant# 113166) and CFI-LOF grant# 25116.