Identification of Sjögren's syndrome oral fluid biomarker candidates following high-abundance protein depletion

Omer Deutsch, Guy Krief, Yrjö T. Konttinen, Batia Zaks, David T. Wong, Doron J. Aframian, Aaron Palmon*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

51 Scopus citations

Abstract

Objective: SS is an autoimmune exocrinopathy affecting ~1 million patients in the USA that is diagnosed mostly in middle-aged women. Oral fluids (OFs) serving as the mirror of the body were suggested as an ideal non-invasive diagnostic tool. Previously we developed depletion techniques for OF high-abundance proteins to increase visualization of low-abundance proteins. Therefore the aim of this study was to examine the effect of depletion pretreatments on the identification potential of SS OF biomarker candidates. Methods: Unstimulated OFs were collected from 18 female SS patients and 18 healthy age- and gendermatched controls. High-abundance proteins were depleted using affinity and immunodepletion methodologies followed by semi-quantitative two-dimensional gel electrophoresis and quantitative dimethylation liquid chromatography tandem mass spectrometry (LC-MS/MS). To initially validate the MS results, western blotting was performed. Results: The use of depletion strategy before proteomics analysis increased identification ability by 3-fold. Overall, 79 biomarker candidates were identified. Proteins with the most pronounced fold changes were related to SS serum or tissue factors. In addition, bioinformatics analysis of proteins with a >3-fold increase in SS patients showed calcium-binding proteins, defence-response proteins, proteins involved in apoptotic regulation, stress-response proteins and cell motion~related proteins. Preliminary validation by western blotting of profilin and CA-I indicated similar expression profile trends to those identified by quantitative MS. Conclusion: The significance of OF novel depletion methodologies is clearly demonstrated for increased visibility of biomarker candidates as well as for unveiling possible mechanisms involved in this syndrome. This represents a major contribution to our ability to use OF as a future diagnostic fluid.

Original languageAmerican English
Article numberkeu405
Pages (from-to)884-890
Number of pages7
JournalRheumatology
Volume54
Issue number5
DOIs
StatePublished - 10 Apr 2014

Bibliographical note

Publisher Copyright:
© The Author 2014.

Keywords

  • Biomarker
  • Oral fluid
  • Protein depletion
  • Salivary gland
  • Sjögren's syndrome

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