Quantitative phosphoproteome of whole saliva supernatant in healthy subjects and periodontal patients
Date
2012
DOI
Authors
Nouh, Hesham M.
Version
OA Version
Citation
Abstract
Periodontal disease can be defined as the presence of gingival inflammation characterized by pathological detachment of collagen fibers from the cementum, alveolar bone resorption, tooth mobility and in severe cases tooth loss. Such inflammatory reactions will alter the oral environment including oral flora and salivary and gingival crevicular fluid compositions. Saliva is secreted into the oral cavity, surrounding the gums and teeth which make it an ideal medium to represent the disease, not only on a local level, but also at a systemic level. Phosphoproteins with significant biological functions have been identified and are well characterized in whole saliva. The current quantitative analysis allows us to compare between healthy and periodontally affected subjects using state-of-the-art mass spectrometry technology. The objective was to develop and utilize novel strategies and chemistries specifically designed to enable a large-scale quantitative phosphoproteome analysis using mass spectrometry. Secondly, to quantify and evaluate on a large scale the phosphoproteome of whole saliva supernatant (WSS) in health versus the diseased state using high throughput mass spectrometric techniques. The results of such study will establish overall alterations in phosphorylation states of salivary phosphoproteins critical for their biological functions as well as highlight those phosphoproteins derived from the local microenvironment of the disease.
In order to achieve these goals, we introduced two key approaches; (i) phosphoprotein specific stable isotope labeling for relative quantitation, and (ii) phosphoproteins enrichment to overcome dynamic protein range. We have utilized a readily available bi-functional thiol-reagent, dithiothreitol ([H1]DTT) and its deuterated isotope, [D6]DTT, for chemical derivatization of the phospho-serine/-threonine containing proteins for relative quantitation; and covalent disulfide-thiol-interchange chromatography or immobilized metal affinity chromatography (IMAC) for phosphopeptide enrichment.
For this study, 80 whole saliva samples, 40 being from healthy individuals and 40 from periodontal patients, were collected under masticatory stimulation. The combined chemical strategy and mass spectrometric technology led to the identification and relative quantitation of 137 phosphoproteins in WSS between healthy and periodontal samples. These specific approaches not only provided the identity of the phosphoproteins and their phosphopeptides, but also the precise site(s) of phosphorylation.
Overall, this study established the first large-scale quantitative phosphoproteome of WSS which covers a wide range of biological and molecular functions that are likely to contribute to our understanding of the changes that occur during transformation to disease as well the discovery of potential useful biomarkers for oral and systemic diagnostics.
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Dissertation (DScD) --Boston University, Henry M. Goldman School of Dental Medicine, 2012 (Department of Periodontology and Oral Biology).
Includes bibliographic references: leaves 136-147.
Dissertation (DScD) --Boston University, Henry M. Goldman School of Dental Medicine, 2012 (Department of Periodontology and Oral Biology).
Includes bibliographic references: leaves 136-147.
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This work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.