iTRAQ proteomic analysis of exosomes derived from synovial fluid reveals disease patterns and potential biomarkers of Osteoarthritis

The exosomes derived from synovial fluid (SF-exo) are indicative of the condition of the originating cell. The proteomics profiles of SF-exo are of great interest for the diagnosis of Osteoarthritis (OA). To delineate the proteomic differences between SF-exo from OA patients and those from healthy individuals, an iTRAQ quantitative proteomics was performed. A total of 439 proteins were identified, with 20 proteins exhibiting increased expression and 5 showing decreased expression in OA group. Bioinformatic analysis showed these differentially expressed proteins (DEPs) were involved in various immunity-related process terms, including complement activation and antigen binding. For further screening, we download a publicly dataset of synovial fluid and compared with our dataset. This comparison identified 5 DEPs were overlapping in two datasets, Protein-protein interaction showed C3, C4B and APOM were part of a tight interaction network. Receiver operating characteristic curve analysis and enzyme-linked immunosorbent assay implied that the 5 DEPs (C3, C4B, APOM, MMP3, DPYSL2) derived from SF-exo were potential diagnostic biomarkers for OA. In conclusion, our study first described the proteomic landscape of SF-exo in OA and identified several potential biomarkers. These findings may provide valuable insights for diagnosis and treatment of OA.