IADR Abstract Archives
Proteome of Dental Cementum from Human Deciduous and Permanent Teeth
Objectives: The dental cementum (DC) is a mineralized tissue covering tooth roots that plays a critical role in tooth attachment. Root resorption is physiological on exfoliating deciduous teeth, however, is always pathological on permanent teeth. It is not well understood why some disorders manifest differently in deciduous vs. permanent teeth, and what directs and allows resorption of deciduous vs. permanent tooth roots. We hypothesized that distinct protein fingerprints for DC from deciduous (DecDC) and permanent (PermDC) teeth could provide insights into physiological differences and pathological conditions.
Methods: Protein extracts were obtained from deciduous (n=25) and permanent (n=12) teeth, and pooled together (five pools of DecDC and four pools of PermDC). Samples were denatured, followed by protein extraction reduction, alkylation and digestion, and analyzed by liquid chromatography mass spectrometry (LC-MS/MS). The beta-binomial statistical test was applied to normalized spectrum counts with 5% significance level to determine differentially expressed proteins (PDE). Immunohistochemistry was used to validate selected findings.
Results: A total of 510 proteins were identified: 123 (24.1%) exclusive to DecDC, 128 (25.1%) exclusive to PermDC and 259 (50.8%) expressed in both DecDC and PermDC. Out of the 60 PDEs identified, 28.3% were found in DecDC, including myeloperoxidase (MPO), whereas 71.7% were detected in PermDC and included decorin (DCN) and osteocalcin (BGLAP). Overall, gene ontology (GO) analysis indicated that PDEs were related to the biological processes including: localization, response to stress and molecular function: structural molecular activity, and macromolecular complex binding. Immunohistochemistry confirmed the trends for selected differentially expressed proteins in decalcified sections of human deciduous and permanent teeth.
Conclusions: Despite presenting a highly similar proteome, DecDC and PermDC ECM displayed clear distinctions, suggesting potential physiological differences between these tissues. These findings may lead to new insights into physiological and pathological root resorption and differential effects of some disorders on deciduous vs. permanent teeth.
Methods: Protein extracts were obtained from deciduous (n=25) and permanent (n=12) teeth, and pooled together (five pools of DecDC and four pools of PermDC). Samples were denatured, followed by protein extraction reduction, alkylation and digestion, and analyzed by liquid chromatography mass spectrometry (LC-MS/MS). The beta-binomial statistical test was applied to normalized spectrum counts with 5% significance level to determine differentially expressed proteins (PDE). Immunohistochemistry was used to validate selected findings.
Results: A total of 510 proteins were identified: 123 (24.1%) exclusive to DecDC, 128 (25.1%) exclusive to PermDC and 259 (50.8%) expressed in both DecDC and PermDC. Out of the 60 PDEs identified, 28.3% were found in DecDC, including myeloperoxidase (MPO), whereas 71.7% were detected in PermDC and included decorin (DCN) and osteocalcin (BGLAP). Overall, gene ontology (GO) analysis indicated that PDEs were related to the biological processes including: localization, response to stress and molecular function: structural molecular activity, and macromolecular complex binding. Immunohistochemistry confirmed the trends for selected differentially expressed proteins in decalcified sections of human deciduous and permanent teeth.
Conclusions: Despite presenting a highly similar proteome, DecDC and PermDC ECM displayed clear distinctions, suggesting potential physiological differences between these tissues. These findings may lead to new insights into physiological and pathological root resorption and differential effects of some disorders on deciduous vs. permanent teeth.
