Proteomic analysis of acquired enamel pellicle in vivo and saliva under the circadian cycle effect

• Grant number: 22/02424-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2022
• End date: December 31, 2023
• Field of knowledge: Health Sciences - Dentistry - Social and Preventive Dentistry
• Principal Investigator: Talita Mendes Oliveira Ventura
• Grantee: Lucas Bento Camargo Martins
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil
• Associated research grant: 19/26070-1 - Modulation of acquired enamel pellicle to control dental mineral loss: unravelling mechanisms to make therapies possible, AP.TEM

Abstract

The acquired enamel pellicle (AEP) is an integument formed in vivo as a result of the selective adsorption of salivary proteins on the tooth surface, which also contains glycoproteins and lipids. The presence of proteins in the AEP forms a protective interface on the tooth surface, participating in all interfacial events in the oral cavity. It is a bacteria-free organic film that covers dental tissues and is one of the protective factors against erosive tooth wear (ETW). Studies have focused on the characterization and protective impact of the acquired pellicle formed on the enamel surface. However, little is known about the influence of the circadian cycle on changes in the protein composition of the acquired pellicle and saliva. Based on this, the objective of this study will be to evaluate the effect of the circadian cycle on the protein profile of saliva and the acquired pellicle formed on enamel in vivo. Nine volunteers will participate in the research, aged over 18 years, non-smokers, with good general and oral health. After prophylaxis, the acquired pellicle will be formed for 120 min. The collection of PAE and saliva will be carried out in three different periods: formation from 8:00 to 10:00 h (morning period), formation from 14:00 to 16:00 h (afternoon period), and formation from 18:00 at 20:00 h (night period). Unstimulated saliva and pellicles formed at different times (morning, afternoon, and night) will be collected separately for analysis using filter paper soaked in 3% citric acid. Samples will be processed for analysis by nLC-ESI-MS/MS. The MS/MS spectra obtained will be compared with human protein databases (SWISS-PROT). Label-free quantification will be performed using the PLGS software. Salivary flows and saliva pH will also be evaluated in different periods.(AU)