W.L. SIQUEIRA

Boston University, Boston, Massachusetts, United States

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Publications (72)119.6 Total impact

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    ABSTRACT: Objective: To compare the protective effect of Sn- and/or F-containing solutions on enamel and dentin erosion prevention and to analyze the protein profile of the Sn- and F-treated acquired pellicles (AP). Method: Phase I tested four solutions: SnCl2/NaF, NaF, SnCl2 and deionized water (DIW) (as negative control). Forty bovine enamel and dentin specimens (4´4´2mm3) were prepared and randomly allocated to four groups (n=10). Specimens were incubated in clarified human saliva (CHS) for 24h for pellicle formation and were then subjected to a cycling procedure that included 5-min erosive challenges (0.3% citric acid, pH 2.6); 2-min treatments with the test solution (between 1st, 3rd and 6th cycles); 2-h immersions in CHS, and overnight immersions in CHS. Cycles were repeated 6x/day for 5 days. Surface loss (SL) was determined profilometrically. Phase II: Thirty-two (32) bovine enamel specimens (8´8´2 mm3) (n=8) were similarly prepared and incubated in saliva for 24h and then treated with the same solutions used in phase I for 2min followed by CHS immersions for 2h. This cycle was repeated 3x for 1d. The AP formed on the specimens were collected, digested, and analyzed for specific protein content using liquid chromatography electrospray ionization tandem mass spectrometry (LCESI-MS/MS). Result: Phase I: for enamel, SnCl2/NaF, SnCl2, NaF solutions provided 89%, 67%, and 42% SL reduction respectively compared with the control, while in dentin they provided 60%, 23%, and 36%, respectively (all p < 0.05). Phase II: Seventy-two (72) common proteins were identified in AP of all groups, 30 exclusive to DIW, 20 to SnCl2/NaF, 19 to NaF, and 13 to SnCl2. SnCl2/NaF increased the abundance of pellicle proteins more than each one alone. Conclusion: Combination of F and Sn ions provided the best anti-erosive effect. Composition of AP changes with different treatment solutions.
    AADR Annual Meeting & Exhibition 2014; 03/2014
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    ABSTRACT: The acquired enamel pellicle (AEP) is important for minimizing the abrasion caused by parafunctional conditions as they occur for instance during bruxism. It is a remarkable feature of the AEP that a protein/peptide film can provide enough protection in normofunction to prevent teeth from abrasion and chipping. Despite its obvious critical role in the protection of tooth surfaces, the essential mechanical properties of the AEP with regard to this protective function have been poorly characterized. Objective: To measure the adhesion force between histatin 5, a primary AEP component, and hydroxyapatite (HA) surfaces. Methods: Both streptavidin-biotinylated histatin 5 and streptavidin-biotinylated human serum albumin were allowed to adsorb on a silica microsphere attached to an atomic force microscope (AFM) cantilever. A Multimode AFM was used to measure the adhesion force between the cantilevers containing protein-functionalized microspheres and the HA surface. All measurements were performed within a fluid cell containing water. The imaging was performed in tapping mode using a Si3N4 AFM cantilever while the adhesion forces were measured in AFM contact mode using the functionalized cantilever system. Results: A collection of force-distance curves (~3,000/replicate) was used to generate histograms that illustrate the adhesion force between the HA surface and histatins 5 or albumin. Histatin 5 (>1.830 nN) exhibited stronger adhesion forces to the HA surface than albumin (>0.282 nN). Conclusion: This study represents an objective approach to adhesion force measurements between histatin 5 and HA, and provides the experimental basis for measuring the same parameters for other AEP constituents. Such knowledge will help in the design of synthetic proteins and peptides with clinical benefits for protective functions of the enamel surface. Support: NSERC grant #371813, CIHR grants #106657/#97577 CFI-LOF grant #25116. WLS is recipient of a CIHR New Investigator Award grant #113166, NIH/NIDCR/NIAID grants DE05672, DE07652, AI087803 and AI101067.
    AADR Annual Meeting & Exhibition 2014; 03/2014
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    ABSTRACT: Our group demonstrated that in vivo acquired enamel pellicle (AEP) is formed by the adsorption of successive layers of protein to hydroxiapatite, which consists of initial binding to enamel and subsequent protein-protein interactions. However, information regarding the type of saliva that contributed for the AEP formation is quite limited. We hypothesized that according to type saliva stimulus, a different AEP proteome will be originated. Objective: AEP formed under different types of salivary stimuli will be compared by using relative proteome quantification based on mass spectrometry. Method: AEP was collected from nine healthy subjects after 2 hours pellicle formation under different type of salivary stimulation: resting condition, mechanical and gustatory stimulation. Pooled samples from each group were subjected to nano-liquidchromatography electro-spray-ionization tandem mass-spectrometry. Results: A total of 122 proteins was identified and 51 proteins were common to all three testedconditions. From those proteins, relative proteome quantification was carried out. Critical AEP proteins such as carbonic anhydrase VI, mucins and cystatins showed significant protein abundance difference among the three conditions. Conclusion: This study is the first to use relative quantitative proteomics based on mass spectrometry to explore different types of saliva stimulus on the AEP formation. Our data suggest that obtained AEP protein profile after each salivary stimulus is similar. In addition, well-recognized enamel demineralization functional AEP proteins such as histatins, statherin and acidic PRP1 were detected in all conditions, which highlighted the mainly protective characteristic of this tooth integument to maintain enamel homeostasis. Support: Natural Sciences and Engineering Research Council of Canada (NSERC grant #371813), and the Canadian Institutes of Health Research, (CIHR grant # 106657 and grant # 97577) WLS is recipient of a CIHR New Investigator Award (grant # 113166), FAPESP
    AADR Annual Meeting & Exhibition 2014; 03/2014
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    ABSTRACT: Moebius syndrome (MS) is a congenital condition mainly characterized by total or partial palsy of facial and abducens nerves. The involvement of these nerves on MS is responsible for unique features of this syndrome, such as, inability to move the eyes laterally and lack of bi- unilateral facial expression (mask-like face). We hypothesize that these deficiencies can affect the salivary gland, consequently modifying the salivary proteome in these subjects. Moreover, due to the single characteristics of this syndrome, we will also evaluate if these individuals could fit as a suitable in vivo study model to the influence of the nerve in salivary composition. Objectives: Explore the salivary proteome in subjects affected by MS. Methods: Bilateral parotid secretion was obtained from MS by using Lashey cup. In addition, each subject was classified according to the most affected facial side. The samples were analyzed by liquid-chromatography-electrospray-ionization-tandem-mass-spectrometry and PAGEs (native cationic and SDS-PAGE). Results: Classical biochemical protein identification methods such as PAGE were not able to provide a significant differentiation between the affected facial sides; on the other hand, innovative and high-sensitive technology such as ESI-MS/MS provides a more detailed protein composition that can facilitate the identification of unique proteome characteristics according to the side. Conclusions: This study is pioneer in exploring saliva composition/secretion side-effect in vivo model. In addition, the outcomes exposed herein open new avenues for the development of an additional exam that can help to determine the degree of involvement of the salivary glands in this syndrome. Support: Natural Sciences and Engineering Research Council of Canada (NSERC grant #371813), and the Canadian Institutes of Health Research, (CIHR grant # 106657 and grant # 97577) WLS is recipient of a CIHR New Investigator Award (grant # 113166).
    AADR Annual Meeting & Exhibition 2014; 03/2014
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    ABSTRACT: Secondary caries at the resin-dentin interface is a major reason for resin composites restorations failure that reduces the service life of the restorations with tremendous financial and health burden on the society. Breakdown of the resin-dentin interface by salivary and bacterial esterases generates the biodegradation by-products (BBPs) triethylene-glycol (TEG) and Bis-hydroxy-propoxy-phenyl-propane (Bis-HPPP). Objectives: To investigate the effects of TEG and/or Bis-HPPP on the expression of S. mutans virulence genes and related proteins that contribute to its cariogenicity. Methods: Quantitative real-time PCR and label-free quantitative proteomics analysis were employed to measure gene expression and protein abundance of planktonic and/or biofilm cultures of S. mutans-UA159 in the presence of clinically-relevant concentrations of TEG and/or Bis-HPPP (0.001, 0.01, 0.1 and 1mM) at physiological (7.0) and pathogenic (5.5) pHs. Results: TEG at 0.01 and/or 0.1mM induced up-regulation of Glucosyltransferases-B and-C, Glucan binding protein-B, and comCDE at pH 5.5, more significantly in biofilm vs. planktonic cells (P<0.001). In contrast, at pH 7.0 TEG had no effect on the expression of those genes in biofilms. Bis-HPPP up-regulated all tested genes except comE at almost all concentrations in biofilm cells vs. no Bis-HPPP control at pH 5.5, while some of the genes were mildly down-regulated by Bis-HPPP in planktonic cultures. At pH 7.0, Bis-HPPP had no effect on biofilms, but planktonic cells had some genes up-regulated at 0.01 or 0.1mM. Quantitative proteomics showed that the protein abundance of gtfB, comD, comE and atpH, were significantly higher in the presence of several concentrations of TEG compared to no TEG control (P<0.05). Conclusion: Composites and adhesive-derived BBPs increase S. mutans pathogenicity by up-regulating important caries-related genes and their related proteins in in vivo-relevant concentrations, especially under cariogenic pH and growth-mode conditions. These observations could potentially explain the higher incidence of recurrent caries and reduced clinical performance of resin composites.
    AADR Annual Meeting & Exhibition 2014; 03/2014
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    ABSTRACT: Candida albicans is the most pathogenic fungal species, commonly colonizing human mucosal surfaces. As a polymorphic species, C. albicans is capable of switching between yeast and hyphal forms, causing an array of mucosal and disseminated infections with high mortality. While the yeast form is most commonly associated with systemic disease, the hyphae are more adept at adhering to and penetrating host tissue and are therefore frequently observed in mucosal fungal infections, most commonly oral candidiasis. Objective:To evaluate the potential of Histatin 5 to protect the Human Oral Epithelium against C. albicans adhesion. Methods:Human Oral Epithelial Tissues (HOET) were incubated with PBS containing histatin 5 for 2 h, followed by incubation with C. albicans for 1 h at 37 °C. The tissues were then washed several times in PBS, transferred to fresh RPMI and incubated for 16 h at 37°C at 5 % CO2. HOET were then prepared for histopathological analysis using light microscopy. In addition, the TUNEL assay was employed to evaluate the apoptosis of epithelial cells using fluorescent microscopy. Proteins released from HOET and from C. albicans-incubated HOET were subjected to relative proteome quantification by mass spectrometry. Results:HOET preincubated with histatin 5 showed a lower rate of C. albicans growth and cell apoptosis when compared to the control groups (HOET alone and HOET incubated with C. albicans). The incubation of HOET with histatin 5 resulted in distinct proteome changes in the incubation buffer compared to both control groups. Conclusions:The data suggest that the coating with histatin 5 is able to reduce C. albicans colonization of epithelial cell surfaces and also protect the basal cell layers from undergoing apoptosis. Supported by:NIH/NIDCR/NIAID grants DE05672, DE07652, AI087803 and AI101067, FAPESP Grants#2011/23540-5, 2011/23543-4 and 2013/15412-2, NSERC grant#371813, CIHR grants#106657/#97577 and, CFI-LOF grant#25116. WLS is recipient of a CIHR New Investigator Award grant#113166.
    AADR Annual Meeting & Exhibition 2014; 03/2014
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    ABSTRACT: The acquired enamel pellicle (AEP) is important for minimizing the abrasion caused by parafunctional conditions as they occur, for instance, during bruxism. It is a remarkable feature of the AEP that a protein/peptide film can provide enough protection in normofunction to prevent teeth from abrasion and wear. Despite its obvious critical role in the protection of tooth surfaces, the essential adhesion features of AEP proteins on the enamel surface are poorly characterized. The objective of this study was to measure the adhesion force between histatin 5, a primary AEP component, and hydroxyapatite (HA) surfaces. Both biotinylated histatin 5 and biotinylated human serum albumin were allowed to adsorb to streptavidin-coated silica microspheres attached to atomic force microscope (AFM) cantilevers. A multimode AFM with a Nanoscope IIIa controller was used to measure the adhesion force between protein-functionalized silica microspheres attached to cantilever tips and the HA surface. The imaging was performed in tapping mode with a Si3N4 AFM cantilever, while the adhesion forces were measured in AFM contact mode. A collection of force-distance curves (~3,000/replicate) was obtained to generate histograms from which the adhesion forces between histatin 5 or albumin and the HA surface were measured. We found that histatin 5 exhibited stronger adhesion forces (90% >1.830 nN) to the HA surface than did albumin (90% > 0.282 nN). This study presents an objective approach to adhesion force measurements between histatin 5 and HA, and provides the experimental basis for measuring the same parameters for other AEP constituents. Such knowledge will help in the design of synthetic proteins and peptides with preventive and therapeutic benefits for tooth enamel.
    Journal of dental research 03/2014; · 3.46 Impact Factor
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    ABSTRACT: Dental erosion is a multifactorial condition that can result in the loss of tooth structure and function, potentially increasing tooth sensitivity. The exposure of enamel to acids from non-bacterial sources is responsible for the progression of erosion. These erosive challenges are counteracted by the anti-erosive properties of the acquired pellicle (AP), an integument formed in vivo as a result of selective adsorption of salivary proteins on the tooth surface, containing also lipids and glycoproteins. This review provides an in-depth discussion regarding how the physical structure of the AP, along with its composition, contributes to AP anti-erosive properties. The physical properties that contribute to AP protective nature include pellicle thickness, maturation time, and site of development. The pellicle contains salivary proteins embedded within its structure that demonstrate anti-erosive properties; however, rather than individual proteins, protein-protein interactions play a fundamental role in the protective nature of the AP. In addition, dietary and synthetic proteins can modify the pellicle, enhancing its protective efficiency against dental erosion. The salivary composition of the AP and its corresponding protein-profile may be employed as a diagnostic tool, since it likely contains salivary biomarkers for oral diseases that initiate at the enamel surface, including dental erosion. Finally, by modifying the composition and structure of the AP, this protein integument has the potential to be used as a target-specific treatment option for oral diseases related to tooth demineralization.
    Archives of oral biology 02/2014; 59(6):631-638. · 1.65 Impact Factor
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    ABSTRACT: Genetic factors influence the effects of fluoride (F) on amelogenesis and bone homeostasis but the underlying molecular mechanisms remain undefined. A label-free proteomics approach was employed to identify and evaluate changes in bone protein expression in two mouse strains having different susceptibilities to develop dental fluorosis and to alter bone quality. In vivo bone formation and histomorphometry after F intake were also evaluated and related to the proteome. Resistant 129P3/J and susceptible A/J mice were assigned to three groups given low-F food and water containing 0, 10 or 50 ppmF for 8 weeks. Plasma was evaluated for alkaline phosphatase activity. Femurs, tibiae and lumbar vertebrae were evaluated using micro-CT analysis and mineral apposition rate (MAR) was measured in cortical bone. For quantitative proteomic analysis, bone proteins were extracted and analyzed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS), followed by label-free semi-quantitative differential expression analysis. Alterations in several bone proteins were found among the F treatment groups within each mouse strain and between the strains for each F treatment group (ratio ≥1.5 or ≤0.5; p<0.05). Although F treatment had no significant effects on BMD or bone histomorphometry in either strain, MAR was higher in the 50 ppmF 129P3/J mice than in the 50 ppmF A/J mice treated with 50 ppmF showing that F increased bone formation in a strain-specific manner. Also, F exposure was associated with dose-specific and strain-specific alterations in expression of proteins involved in osteogenesis and osteoclastogenesis. In conclusion, our findings confirm a genetic influence in bone response to F exposure and point to several proteins that may act as targets for the differential F responses in this tissue.
    PLoS ONE 01/2014; 9(12):e114343. · 3.53 Impact Factor
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    ABSTRACT: OBJECTIVE: Low-amplitude whole-body vibration has been adopted for the treatment of back pain and spine pathologies; however, there is limited knowledge of the impact of vibration on the intervertebral disc (IVD). We examined the effects of acute vibration on anabolic and catabolic pathways in the IVD and characterized the dependence of these changes on time and frequency. METHODS: Custom-designed platforms were developed to apply acute vibration to ex vivo and in vivo mouse models. Spinal segments (ex vivo) or mice (in vivo) were subjected to vibration (30 min, 15-90 Hz, peak acceleration 0.3 g) and IVDs were examined at specific times post-vibration. Gene expression was quantified using real-time PCR and protein levels were examined by quantitative mass spectrometry and immunofluorescence. RESULTS: In the ex vivo model, acute vibration at 15 Hz induced expression of anabolic genes (aggrecan, biglycan, decorin, type I collagen, Sox9) and suppressed expression of Mmp13, with the most pronounced changes detected 6 h following vibration. These beneficial effects were frequency dependent, no longer evident between 45-90 Hz. In vivo, the effects on anabolic gene expression were even more robust and were accompanied by decreased expression of Adamts4/5 and Mmp3. Moreover, significant increases in the protein levels of type I collagen biglycan, decorin and aggrecan were detected in vivo. CONCLUSIONS: These findings demonstrate dramatic anabolic effects of acute vibration on IVD tissues, responses that are dependent on frequency. Similarity of responses in vivo and ex vivo indicates that at least some effects of vibration are tissue autonomous. © 2013 American College of Rheumatology.
    Arthritis & Rheumatology 05/2013; · 7.48 Impact Factor
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    ABSTRACT: Objective: This study evaluated the use of non-stimulated and stimulated human saliva in commercial test for the detection of dengue NS1 protein during the clinical phase of dengue virus (DENV) infection—an immunochromatographic test allowing rapid detection of the NS1 antigen, “Dengue NS1 Ag STRIP (Bio-Rad)”. Method: Non stimulated saliva (10 patients) and stimulated saliva (10 patients) samples from 20 patients with acute infection of one of the four dengue serotypes, detected by RT-PCR and/or virus isolation and 20 healthy, non-stimulated saliva (10 patients) and stimulated saliva (10 patients) samples, were used. In a single plastic tube was distributed 50 μl of saliva to be tested with Dengue NS1 Ag STRIP (Bio-Rad) for four groups. Result: The sensitivity of the Dengue NS1 Ag STRIP to patients with acute infection of one of the four dengue serotypes wasn’t detected. There was no difference for samples of non-stimulated and stimulated saliva in both groups of patients with dengue fever. The specificity was 100% to healthy patients for non-stimulated and stimulated saliva samples. Conclusion: Our findings could not support the use of diagnostic tools based on the NS1 antigen detection for the diagnosis of acute DENV infection using non-stimulated and stimulated human saliva.
    IADR/AADR/CADR General Session and Exhibition 2013; 03/2013
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    ABSTRACT: Objectives: The initial tooth integument formed on enamel surfaces is the acquired enamel pellicle (AEP) which is formed by the selective adsorption of oral fluid proteins and peptides. This is followed by selective binding of oral microorganisms. Our recent studies have identified the early microbial colonizers in the 0-6h time frame, using DNA-DNA hybridization checkerboard and HOMIM microarray technologies. The sequential and parallel pattern of AEP and biofilm formation, though, has not yet been characterized. Insights into the mechanistic driving forces of these processes are vital for understanding the transitions from physiological to pathological conditions. The objective of our studies is to understand the biochemical determinants that dictate protein as well as bacterial adsorption, and to correlate both processes to ultimately gain insights into the critical steps in the formation of mature dental biofilm. Methods: Tooth integuments were collected at 0, 2, 4 or 6 hours after thorough cleaning of tooth surfaces. The proteins in the AEP samples are being quantitatively analyzed using label-free LC-ESI-MS/MS, whereas the microbial compositions were determined using the HOMIM microarray. Results: Samples have been obtained from 14 participating orally healthy subjects. Our earlier data indicated that the bacterial binding for the first 6 hours of integument formation comprise predominantly the species of Gemella haemolysans, Streptococcus cristatus, S. oralis, S. parasanguis I and II (p<0.05) as well as S. anginosus and intermedius, S. mitis and S. Cluster I. Both the raw label free LC-ESI-MS/MS data and microbial results will be computed to evaluate and correlate the protein and species patterns of early biofilm development. Conclusions: With the in vivo AEP/early biofilm collection techniques developed in our laboratories and novel sensitive quantitatition assays new insights will be gained into the interplay between protein/peptides and bacteria in early tooth integuments.
    IADR/AADR/CADR General Session and Exhibition 2013; 03/2013
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    ABSTRACT: 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.
    03/2013
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    ABSTRACT: Acquired enamel pellicle (AEP) is a protein film that forms on the enamel surface of teeth by selective adsorption of proteins and peptides present in the mouth. This protein film forms the interface between enamel and the damage oral biofilm, which modulates the attachment of bacteria found in oral biofilm. The overall goal of this study was to gain insight into the biological formation of the human in vivo AEP. This study hypothesized that AEP is created by the formation of successive protein layers, which consist of initial binding to enamel and subsequent protein-protein interactions. This hypothesis was examined by observing quantitative and qualitative changes in pellicle composition during the first two hours of AEP formation in the oral cavity. Quantitative mass spectrometry approaches were used to generate an AEP protein profile for each time-point studied. Relative proteomic quantification was carried out for the 50 proteins observed in all four time-points. Notably, the abundance of important salivary proteins, such as histatin 1, decrease with increasing of the AEP formation, while other essential proteins such as statherin showed constant relative abundance in all time-points. In summary, this is the first study that investigates the dynamic process to the AEP formation by using proteomic approaches. Our data demonstrated that there are significant qualitative and quantitative proteome changes during the AEP formation, which in turn will likely impact the development of oral biofilms.
    PLoS ONE 01/2013; 8(7):e67919. · 3.53 Impact Factor
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    ABSTRACT: Understanding the composition and structure of the acquired enamel pellicle (AEP) has been a major goal in oral biology. Our lab has conducted studies on the composition of AEP formed on permanent enamel. The exhaustive exploration has provided a comprehensive identification of more than 100 proteins from AEP formed on permanent enamel. The AEP formed on deciduous enamel has not been subjected to the same biochemical characterization scrutiny as that of permanent enamel, despite the fact that deciduous enamel is structurally different from permanent enamel. We hypothesized that the AEP proteome and peptidome formed on deciduous enamel may also be composed of unique proteins, some of which may not be common with AEP of permanent enamel explored previously. Pellicle material was collected from 10 children (aged 18-54 months) and subjected to mass spectrometry analysis. A total of 76 pellicle proteins were identified from the deciduous pellicle proteome. In addition, 38 natural occurring AEP peptides were identified from 10 proteins, suggesting that primary AEP proteome/peptidome presents a unique proteome composition. This is the first study to provide a comprehensive investigation of in vivo AEP formed on deciduous enamel.
    International Journal of Molecular Sciences 01/2013; 14(1):920-34. · 2.46 Impact Factor
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    ABSTRACT: To quantify the proteome composition of the GCF in periodontal health (HH) and in sites with different clinical conditions in chronic periodontitis (CP) subjects. 5 subjects with HH and 5 with CP were submitted to full-mouth periodontal examination, and GCF sampling. Sites in the CP group were classified and sampled as periodontitis (P, probing depth, PD>4 mm), gingivitis (G, PD≤3mm with bleeding on probing, BOP), and healthy sites (H, PD≤3mm without BOP). GCF proteins were subjected to liquid chromatography electrospray ionization mass spectrometry for identification, characterization and quantification. 230 proteins were identified; 145 proteins were detected in HH, 214 in P, 154 in G, and 133 in H. Four proteins were exclusively detected at HH, 43 proteins at P, 7 proteins at G, and 1 protein at H. Compared to HH group, 35 and 6 proteins were more abundant in P and G (p<0.001), respectively; and 4, 15 and 37 proteins were less abundant in P, G and H (p≤0.01), respectively. There are marked differences in the GCF proteome according to disease profile. Comprehension of the role of the identified proteins in the etiopathogenesis of periodontal disease may lead to biomarkers definition.
    PLoS ONE 01/2013; 8(10):e75898. · 3.53 Impact Factor
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    ABSTRACT: With recent progress in the analysis of the salivary proteome, the number of salivary proteins identified has increased dramatically. However, the physiological functions of many of the newly discovered proteins remain unclear. Closely related to the study of a protein's function is the identification of its interaction partners. We investigated interactions among and functions of histatin 1 and the other proteins that are present in saliva by using high-throughput mass spectrometric techniques. This led to the identification of 43 proteins able to interact with histatin 1. In addition, we found that these protein–protein interactions protect complex partners from proteolysis and modulate their antifungal activity. Our data contribute significantly to characterization of the salivary interactome and to understanding the biology of salivary protein complexes.
    Proteomics 11/2012; 12(22). · 4.43 Impact Factor
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    ABSTRACT: Background: Saliva is supersaturated with respect to calcium and phosphate ions. Salivary ions may well play a role in the subsequent adsorption of proteins and consequently in the formation of the acquired enamel pellicle. Among several biological functions, the enamel pellicle forms a selectively permeable barrier that regulates demineralization processes. Aim: The aim of this study was to evaluate the importance of salivary proteins when adsorbed on enamel surface and the resultant protective effect against demineralization without the presence of salivary ions. Methods: Enamel surfaces were coated with whole saliva, parotid saliva, dialyzed whole saliva or dialyzed parotid saliva (molecular weight cutoff 1 kDa). Adsorption was allowed to proceed for a period of 2 h. Enamel specimens were then washed with deionized water and immersed into a demineralization solution of pH 4.5 for 12 days. This solution was used to measure the amount of calcium and phosphate released from enamel specimens after the demineralization period. Results: All coated specimen groups showed a significantly higher protection than those not coated with any type of saliva. In addition, undialyzed saliva (whole saliva and parotid saliva) was more effective in protecting the enamel against demineralization than dialyzed saliva. Conclusion: The present investigation indicates that the ionic composition of saliva can amplify the demineralization protection effect by reducing acid-induced enamel demineralization. Moreover, a protective effect of salivary proteins without presence of ions was demonstrated in this study.
    Caries Research 10/2012; 47(1):56-62. · 2.51 Impact Factor
  • W L Siqueira, W Custodio, E E McDonald
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    ABSTRACT: The acquired enamel pellicle (AEP) is a thin acellular film that forms on tooth surfaces upon exposure to the oral environment. It consists predominantly of salivary proteins, but also includes non-salivary-derived proteins, carbohydrates, and lipids. Since it is the interface between teeth and the oral environment, the AEP plays a key role in the maintenance of oral health by regulating processes including lubrication, demineralization, and remineralization and shaping the composition of early microbial flora adhering to tooth surfaces. Knowledge of the 3D structure of the AEP and how that correlates with its protective functions may provide insight into several oral pathological states, including caries, erosion, and periodontal disease. This review intends to update readers about the latest discoveries related to the formation, ultrastructure, composition, and functions of the AEP, as well as the future of pellicle research, with particular emphasis on the emerging role of proteomic and microscopy techniques in oral diagnosis and therapeutics.
    Journal of dental research 09/2012; · 3.46 Impact Factor

Publication Stats

516 Citations
119.60 Total Impact Points

Institutions

  • 2006–2014
    • Boston University
      • Department of Periodontology and Oral Biology
      Boston, Massachusetts, United States
    • Federal University of Rio de Janeiro
      Rio de Janeiro, Rio de Janeiro, Brazil
  • 2009–2013
    • The University of Western Ontario
      • Schulich School of Medicine and Dentistry
      London, Ontario, Canada
  • 2010
    • Boston Medical Center
      Boston, Massachusetts, United States
  • 2008
    • Beverly Hospital, Boston MA
      Beverly, Massachusetts, United States
  • 2002–2008
    • University of São Paulo
      • Centro de Pesquisas Audiológicas (CPA)
      Ribeirão Preto, Estado de Sao Paulo, Brazil
  • 2007
    • Universidade Cruzeiro do Sul
      San Paulo, São Paulo, Brazil