Metaproteomics associated with severe early childhood caries highlights the differences in salivary proteins.

Abstract

OBJECTIVE\nTo investigate the salivary metaproteomic characteristics of the children with and without severe early childhood caries (S-ECC).\n\n\nDESIGN\nIn this study, we collected unstimulated saliva samples from 34 children (age 3-4 years) with caries free (NC, dmfs (= index of decayed, missing due to caries, or filled tooth surfaces) = 0, n = 23) and with S-ECC (dmfs≥10, n = 11). Salivary proteins were extracted and reduced, and then a Liquid Chromatography/Mass Spectrometry system was used to identify proteins.\n\n\nRESULTS\nNearly 3000 proteins were identified in this study, and about 3.5 % of the proteins originated from human while 86 % were derived from microbes. The salivary protein types in the NC group were statistically greater than those in the S-ECC group (P <0.05). Specifically, the salivary protein types derived from microbes in the NC group were significantly greater than those in the S-ECC group. Three proteins, human lactoferrin, penicillin-binding protein 1C [Burkholderia ubonensis], human alpha-defensin 1 (F28a mutant), were decreased statistically in the NC group compared to the S-ECC group (P < 0.05). Only one protein, 50S ribosomal protein L17 secreted by Haemophilus haemolyticus, was significantly increased in the NC group compared to the S-ECC group. Salivary IgA was the top highest protein in the NC group whereas human lysozyme was the top highest protein in the S-ECC group.\n\n\nCONCLUSIONS\nThe differential proteins recognized in this study may be conducive for finding a caries biomarker. Understanding the metaproteomic characteristics can help us to control the caries from human origin and microbial origin.