Phenotyping multiple subsets in Sj\xf6gren\u2019s syndrome: a salivary proteomic SWATH-MS approach towards precision medicine

Antonella Cecchettini,Francesco Ferro,Marta Mosca,Silvia Rocchiccioli,Letizia Mattii,Nadia Ucciferri,Enza Polizzi,Francesca Sernissi,Chiara Baldini,Stefano Bombardieri,Francesco Finamore,Valentina Donati

doi:10.1186/s12014-019-9245-1

Antonella Cecchettini, Francesco Ferro + Show 10 more

Open Access

https://doi.org/10.1186/s12014-019-9245-1

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Abstract

BackgroundThis proof of concept study was aimed at characterizing novel salivary biomarkers specific for different subsets in primary Sjögren’s syndrome (pSS) in order to improve patients’ profiling.MethodspSS patients were stratified in three subgroups according to both (a) focus score in the minor salivary gland biopsies (i.e. intensity of immune cell infiltration in the tissue) and (b) unstimulated salivary flow rate. Healthy volunteers were included as controls. A nano-HPLC-SWATH-MS approach was used for the analysis of saliva proteome of different subsets.ResultsWe found 203 differentially expressed proteins in pSS patients with respect to controls with evident differences in the expression of normal constituents of the human salivary proteome (i.e. prolactin-inducible protein, proline-rich proteins, cystatins) and several mediators of inflammatory processes. The comparative analysis of the pSS phenotypes unrevealed 63 proteins that were shared and specifically modulated in the three subsets of pSS patients converging on several inflammatory pathways. Among them S100A protein appeared of particular interest merging on IL-12 signaling and being significantly influenced by either salivary flow impairment or intensity of immune cell infiltration in the tissue.ConclusionsConstellations of proteins, including S100A proteins, characterize different pSS subsets reflecting either salivary gland dysfunction or inflammation. Salivary proteomics may foster future research projects ultimately aimed at developing personalized treatments for pSS patients.

Highlights

This proof of concept study was aimed at characterizing novel salivary biomarkers specific for different subsets in primary Sjögren’s syndrome in order to improve patients’ profiling
Translation into clinical practice of the identified putative biomarkers has not been accomplished and primary Sjögren’s syndrome (pSS) inter-subject variability and heterogeneity have not been addressed [26]. In this proof of concept study a high-throughput liquid chromatography coupled to a data-independent sequential window acquisition of all theoretical fragment ion spectra (SWATH-MS) approach was used to search for salivary proteomic biomarkers in pSS specific subsets
For the purpose of this study patients were stratified on the basis of (1) the complexity of lymphocytic infiltration detected in minor salivary gland biopsy (MSGB) and (2) on the variation of their unstimulated salivary flow rate (USFR)

Summary

Introduction

This proof of concept study was aimed at characterizing novel salivary biomarkers specific for different subsets in primary Sjögren’s syndrome (pSS) in order to improve patients’ profiling. Several candidate biomarkers have been proposed including numerous defense proteins, like salivary immunoglobulins, cationic peptides, lysozyme, prolin-rich proteins, Cecchettini et al Clin Proteom (2019) 16:26 mucins and cystatins [12,13,14,15,16,17,18,19,20,21,22,23,24,25] Despite these encouraging results, translation into clinical practice of the identified putative biomarkers has not been accomplished and pSS inter-subject variability and heterogeneity have not been addressed [26]. For the purpose of this study patients were stratified on the basis of (1) the complexity of lymphocytic infiltration detected in MSGB and (2) on the variation of their unstimulated salivary flow rate (USFR)

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