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01.12.2018 | Research | Ausgabe 1/2018 Open Access

Journal of Translational Medicine 1/2018

Comparative salivary proteomics analysis of children with and without dental caries using the iTRAQ/MRM approach

Zeitschrift:
Journal of Translational Medicine > Ausgabe 1/2018
Autoren:
Kun Wang, Yufei Wang, Xiuqing Wang, Qian Ren, Sili Han, Longjiang Ding, Zhongcheng Li, Xuedong Zhou, Wei Li, Linglin Zhang
Wichtige Hinweise

Electronic supplementary material

The online version of this article (https://​doi.​org/​10.​1186/​s12967-018-1388-8) contains supplementary material, which is available to authorized users.

Abstract

Background

Dental caries is a major worldwide oral disease afflicting a large proportion of children. As an important host factor of caries susceptibility, saliva plays a significant role in the occurrence and development of caries. The aim of the present study was to characterize the healthy and cariogenic salivary proteome and determine the changes in salivary protein expression of children with varying degrees of active caries, also to establish salivary proteome profiles with a potential therapeutic use against dental caries.

Methods

In this study, unstimulated saliva samples were collected from 30 children (age 10–12 years) with no dental caries (NDC, n = 10), low dental caries (LDC, n = 10), and high dental caries (HDC, n = 10). Salivary proteins were extracted, reduced, alkylated, trypsin digested and labeled with isobaric tags for relative and absolute quantitation, and then they were analyzed with GO annotation, biological pathway analysis, hierarchical clustering analysis, and protein–protein interaction analysis. Targeted verifications were then performed using multiple reaction monitoring mass spectrometry.

Results

A total of 244 differentially expressed proteins annotated with GO annotation in biological processes, cellular component and molecular function were identified in comparisons among children with varying degrees of active caries. A number of caries-related proteins as well as pathways were identified in this study. As compared with caries-free children, the most significantly enriched pathways involved by the up-regulated proteins in LDC and HDC were the ubiquitin mediated proteolysis pathway and African trypanosomiasis pathway, respectively. Subsequently, we selected 53 target proteins with differential expression in different comparisons, including mucin 7, mucin 5B, histatin 1, cystatin S and cystatin SN, basic salivary proline rich protein 2, for further verification using MRM assays. Protein–protein interaction analysis of these proteins revealed complex protein interaction networks, indicating synergistic action of salivary proteins in caries resistance or cariogenicity.

Conclusions

Overall, our results afford new insight into the salivary proteome of children with dental caries. These findings might have bright prospect in future in developing novel biomimetic peptides with preventive and therapeutic benefits for childhood caries.
Zusatzmaterial
Additional file 1. List of proteins commonly identified by iTRAQ in all saliva samples.
Additional file 2: Figure S1. The correlation analysis between each experimental group and its replicate in iTRAQ quantification. Figure S2. Log ratio of relative intensity for differentially expressed proteins in HDC vs NDC (A), LDC vs NDC (B) and HDC vs LDC (C) groups. Figure S3. Functional annotation of down-regulated proteins for biological process, cellular component and molecular function in HDC vs NDC, LDC vs NDC, and HDC vs LDC groups. Figure S4. Pathway analysis of up-regulated and down-regulated proteins based on KEGG in HDC vs NDC (A), LDC vs NDC (B) and HDC vs LDC (C) groups. Figure S5. Hierarchical Clustering analysis of differentially expressed proteins found commonly in HDC vs NDC, LDC vs NDC, and HDC vs LDC groups. Saliva samples are shown in the columns, and proteins are shown in the rows.
Additional file 3. Category list of differentially expressed proteins commonly or uniquely detected in HDC vs NDC, LDC vs NDC, and HDC vs LDC.
Additional file 4. Category list of pathways involved by differentially expressed proteins in HDC vs NDC (1), LDC vs NDC (2), and HDC vs LDC (3).
Additional file 5. Detailed information from PPI analysis of 42 target proteins.
Additional file 6. Relative protein abundances for 53 target proteins (1), and category list of these proteins commonly or uniquely detected in HDC vs NDC, LDC vs NDC, and HDC vs LDC using MRM (2).
Literatur
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