Analysis of salivary exosomal proteins in young adults with severe periodontitis

Objectives Salivary exosomes harbour numerous constituents associated with oral and systemic diseases. However, no reports addressed components of salivary exosomes in patients with periodontitis. Our study aims to explore salivary exosomal proteins in young adults with severe periodontitis (SP) and to analyse the relationships between different proteins. Materials and Methods We collected saliva from 11 young adults with SP and 11 periodontally healthy subjects. After isolation of salivary exosomes, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to analyse proteins. Gene ontology analysis was performed based on GeneCodis, and interaction network analysis for unique salivary exosomal proteins was performed by STRING. Results Twenty-six proteins were identified only in the SP group, and 58 proteins were identified only in the healthy group. Gene ontology analysis revealed that innate immune response, cytolysis and complement activation were highly enriched in the SP group. Interaction network analysis showed that the correlations among immune-related proteins (e.g. complement components and chemokine (C-C motif) ligand 28) were significant in the SP group. C6 proteins expressed only in the SP group were evaluated by Western blotting. Conclusions Salivary exosomes from periodontitis patients are enriched immune-related proteins that might participate in the immune response during the development of periodontitis.