Identification of acid-resistant proteins in acquired enamel pellicle.
OBJECTIVE
This study characterized the proteome profile of the acquired pellicle formed in vivo on enamel. Changes in this proteome profile after exposure to lactic or citric acid were also evaluated.


METHODS
Volunteers (n=8) were subjected to dental prophylaxis. After 2 h to allow the formation of the acquired pellicle, the teeth were isolated with cotton rolls and 1 mL of citric acid (1%, pH 2.5) or lactic acid (0.1 M pH 4.8) or deionized water was gently applied with a pipette on the anterior teeth (both maxillary and mandibular) for 10 s. In sequence, the pellicle was collected with an electrode filter paper soaked in 3% citric acid. This procedure was repeated for two additional days following a crossover protocol. Proteins were subjected to reverse phase liquid chromatography coupled to mass spectrometry (nLC-ESI-MS/MS). MS/MS data were processed and submitted to Proteome Discoverer software. Searches were done using SWISS-PROT and TrEMBL databases for human proteins.


RESULTS
In total, seventy-two proteins were present in all groups and were submitted to quantitative analysis (SIEVE). Some of these proteins were increased more than two-fold after exposure to the acids. Among them, cystatin-B was increased 20- and 13-fold after exposure to citric and lactic acids, respectively. Additionally, some proteins were identified in only one of the groups (18, 5, and 11 proteins for deionized water, citric and lactic acids, respectively).


CONCLUSIONS
Our results open new insights regarding potentially acid-resistant proteins that could be added to dental products to prevent acidic dissolution of the teeth.
Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
Taísa Ribas
TR
Delecrode
Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada. Electronic address: walter.siqueira@uwo.ca.
Walter Luiz
WL
Siqueira
Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil; Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada.
Flavia Cardoso
FC
Zaidan
Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
Melina Rodrigues
MR
Bellini
Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil; Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada.
Eduardo Buozi
EB
Moffa
Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada; School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.
Maria Carolina Martins
MC
Mussi
Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada.
Yizhi
Y
Xiao
Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil. Electronic address: mbuzalaf@fob.usp.br.
Marília Afonso Rabelo
MA
Buzalaf
D000293:Adolescent; D000328:Adult; D019343:Citric Acid / Q000737:chemistry / Q000494:pharmacology; D018592:Cross-Over Studies; D055313:Cystatin B / Q000494:pharmacology; D003731:Dental Caries / Q000517:prevention & control; D003743:Dental Enamel / Q000737:chemistry* / Q000187:drug effects; D003747:Dental Enamel Solubility / Q000187:drug effects; D044622:Dental Pellicle / Q000737:chemistry* / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry / Q000494:pharmacology; D011506:Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D020543:Proteome / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D017001:Tooth Demineralization / Q000517:prevention & control; D014077:Tooth Erosion / Q000517:prevention & control; D014867:Water / Q000737:chemistry; D055815:Young Adult
D011506:Proteins; D020543:Proteome; D014867:Water; D019343:Citric Acid; D019344:Lactic Acid; D055313:Cystatin B
Acid exposure; Demineralization; Dental caries; Dental erosion; In vivo; Proteomics