Quantitative proteomics of parotid saliva in primary Sjögren's syndrome

Abstract

The diagnosis of primary Sjögren’s syndrome (pSS) is difficult due to the lack of specific laboratory and clinical tests. As an initial step for the global discovery of changes in the abundance of parotid salivary proteins in pSS, a pooled sample was compared to that from healthy control (HC) subjects by multidimensional protein identification technology (MudPIT). A total of 1246 proteins were identified by MudPIT. The abundance of 477 of these proteins did not change, 529 were only detected in either the pSS or HC sample, while 206 of these proteins were significantly up-regulated ≥ 2-fold and 34 were down-regulated ≤ 0.5. Ingenuity Pathway Analyses of differentially expressed proteins identified by MudPIT resulted in the identification of 100 significant pathways. The same samples were quantified in parallel using reversed phase (RP) mass spectrometry. Fifty eight of 71 proteins identified by RP overlapped with MudPIT results. Five proteins were further analyzed by targeted label-free quantification to confirm the similar relative differential expression observed by RP and MudPIT approaches. The present study supports the use of mass spectrometry for global discovery and validation of marker proteins for improved and early diagnosis of pSS.

Identification of potential saliva and tear biomarkers in primary Sjögren’s syndrome, utilising the extraction of extracellular vesicles and proteomics analysis

“…Similarly, previous proteomic studies on whole saliva have determined broad and distinct protein patterns that are characteristic of SS, including secretory proteins, enzymes, highly abundant immune system-related molecules (e.g. β2-microglobulin), and cytokines such as IL-4 and IL-5 [21, 28, 29]. The current STRING analysis of whole saliva also strengthens the concept of involvement and over-activation of the innate and adaptive immune system in SS.…”

“…As a result, several common biomarkers for SS have been found, including secretory proteins, enzymes, highly abundant immune-system-related molecules (e.g. β2-microglobulin), and cytokines such as IL-4 and IL-5 [21, 28, 29]. …”

Membrane transporters in salivary exosomes and microvesicles as biomarkers of systemic or oral disease

“…Proteomic technologies are currently being used to discover disease biomarkers, particularly for oral cancer [25,26], lung disease [27], Sjögren's syndrome [28,29], and gingivitis [30].…”

Childhood Sjögren syndrome

“…In search of SS-specific biomarkers, investigators have studied saliva and tears from SS patients and mouse models. Quantitative proteomic study of parotid saliva identified 529 proteins specific to either primary SS patients or healthy controls, including many proteins with immunologic functions [20]. In tear fluid, immune cell mRNA was detected in autoimmune dacryoadenitis prone mice [21].…”