Proteomic analysis of bone marrow-adherent cells in rheumatoid arthritis and osteoarthritis.

Aim: To elucidate the pathophysiology of rheumatoid arthritis (RA) as well as osteoarthritis (OA), we analyzed protein profiles of bone marrow-derived adherent cells (BMACs) from patients with these diseases.

Methods: Proteins, extracted from BMACs from three RA and three OA patients, were comprehensively analyzed by 2-dimensional differential image gel electrophoresis (2D-DIGE). Then a part of the detected proteins, differently expressed between the two diseases, were identified by mass spectrometric analysis.

Results: 2D-DIGE analysis detected more than 1600 protein spots in both RA and OA BMACs. Out of these, expression of 340 spots was significantly altered between the diseases (more than 1.5-fold: RA > OA, 26 spots; OA > RA, 314 spots; P < 0.05). Eleven protein spots the intensity of which were significantly altered by more than 2.0-fold were identified, which included vimentin and annexin A5 as increased proteins in RA rather than in OA. As increased proteins in OA compared to RA, alpha chain of collagen VI, a membrane anchor for acetylcholine esterase, heat shock protein 27, caldesmon and cytoskeletal proteins, such as beta actin and alpha tubulin, were identified.

Conclusions: We here report different protein profiles of BMACs between RA and OA for the first time. BMACs possessing differently expressed proteins may be involved in the pathophysiology of the two diseases.