Differential protein profiling of synovial fluid from rheumatoid arthritis and osteoarthritis patients using LC–MALDI TOF/TOF

• Published in: Journal of proteomics Vol. 75; no. 10; pp. 2869 - 2878
• Main Authors: Mateos, Jesús, Lourido, Lucía, Fernández-Puente, Patricia, Calamia, Valentina, Fernández-López, Carlos, Oreiro, Natividad, Ruiz-Romero, Cristina, Blanco, Francisco J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Kidlington Elsevier B.V 06.06.2012; Elsevier
• Subjects: Aged; Aged, 80 and over; Arthritis, Rheumatoid - metabolism; Arthritis, Rheumatoid - pathology; Biological and medical sciences; Biomarkers; blood proteins; blood serum; cartilage; Chromatography, Liquid; Diseases of the osteoarticular system; Diverse techniques; extracellular matrix; fibronectins; Fundamental and applied biological sciences. Psychology; high performance liquid chromatography; Humans; immune response; immunoblotting; inflammation; Inflammatory joint diseases; mass spectrometry; Medical sciences; Metabolome; metalloproteinases; Middle Aged; Models, Biological; Molecular and cellular biology; Osteoarthritis; Osteoarthritis - metabolism; Osteoarthritis - pathology; patients; Protein Array Analysis; Proteome - analysis; Proteome - metabolism; Proteomics; Proteomics - methods; Rheumatoid arthritis; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Synovial fluid; Synovial Fluid - chemistry; Synovial Fluid - metabolism; Biomarkers; Synovial fluid; Osteoarthritis; Rheumatoid arthritis; Proteomics; Human; Biological marker; Patient; Protein
• ISSN: 1874-3919; 1876-7737
• DOI: 10.1016/j.jprot.2011.12.042

The purpose of this study was to identify those proteins relatively more abundant in the synovial fluid (SF) of patients suffering from rheumatoid arthritis (RA) and osteoarthritis (OA) using high performance liquid chromatography coupled to mass spectrometry. 20 individual SF samples from each disease were pooled into two groups (RA and OA) to reduce the contribution of extreme individual values. Prior to the proteomic analysis, samples were immunodepleted from the top 20 most abundant plasma proteins, to enrich the lower-abundance protein fractions. Then, they were subjected to protein size fractioning and in-gel digestion, followed by reversed-phase peptide separation in a nano-LC system and subsequent peptide identification by MALDI-TOF/TOF. This strategy led to the identification of 136 different proteins in SF, which is the largest number of SF proteins described up to date by proteomics. A relative quantification of the proteins between RA and OA was carried out by spectral counting analysis. In RA, our results show a greater relative abundance of proteins related to complement activation, inflammation and the immune response, such as the major matrix metalloproteinases and several neutrophil-related proteins. In OA, we detected an increase in proteins involved in the formation and remodeling of the extracellular matrix (ECM), such as fibronectin, kininogen-1, cartilage acidic protein 1 and cartilage oligomeric matrix protein. The results obtained for MMP-1, BGH3, fibronectin and gelsolin were verified by immunoblotting analyses. Some of the novel proteins identified in this work might be relevant not only for increasing knowledge on the etiopathogenesis of RA and OA processes, but also as putative disease biomarkers, as their presence in SF is a prior step to their dilution in serum. This article is part of a Special Issue entitled: Proteomics: The clinical link. [Display omitted] ► Synovial fluid immunodepletion of the 20 most abundant plasma proteins. ► The largest number of different proteins reported up to date in SF by proteomics. ► Relative quantification of RA and OA by nanoLC–MALDI-MS/MS and spectral counting. ► Identification of a novel RA SF proteomic signature. ► Identification of a novel OA SF proteomic signature.