The Exploration of Saliva Proteomics in Predicting Early Childhood Caries

Objectives: To compare the changes of salivary proteins between children with and without caries and predict the risk of caries.
Methods: During the long-term longitudinal follow-up study, stimulated whole saliva samples were collected. Depending on whether caries occurred or not every three months,20 subjects were included and divided into two groups. Children who had caries were assigned to HC group and the rest to HH group (10 for each group). Data-independent acquisition (DIA) and liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-MS/MS) techniques were used to screen proteins which showed no significant difference in HH group, but differentially expressed in HC group. Functional annotation analysis of differential proteins was performed using Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG). By combining the proteins with acceptable caries predictive efficacies, a predictive model was established.
Results: A total of 228 proteins were screened out with no significant difference in HH group, but differentially expressed in HC group. According to GO enrichment analysis, these proteins were involved in acute-phase inflammatory response, transforming growth factor regulation and coagulation function. KEGG pathway enrichment analysis revealed that the most significant enriched pathway was complement and coagulation cascades. Among them, four up-regulated proteins (AHSG, APOA2, AMB, SERPIND1) and three down-regulated proteins (ADIRF, PLIN3, DSC3) had great predictive ability to occurrence of caries. The combination of these 7 proteins showed the predictive value of 0.97.
Conclusions: Salivary proteins had significant differences between caries-affected and caries-free children and play an important role in predicting the occurrence and risk of caries as biomarkers.