Identification of Differentially Expressed Proteins in the Serum for Systemic Juvenile Idiopathic Arthritis Using Next-generation Proteomics
Abstract Systemic juvenile idiopathic arthritis (sJIA) is an autoinflammatory disease caused by high production of inflammatory cytokines. Conventional biomarkers, such as IL-18 are reportedly not always associated with frequent relapses or complication with macrophage activation syndrome (MAS). As few specific biomarkers that can indicate and evaluate the sJIA disease activity have been identified, the discovery of biomarkers is very important. We performed a deep proteomic analysis of serum samples from nine patients with sJIA using highly sensitive mass spectrometry, and identified differentially expressed proteins in various disease phases. We selected 68 proteins (URPs) that were highly expressed in the active phase from total of 2,727 proteins. Pathway analysis revealed that the URPs included proteins related to many immune process and proteasome proteins, which might be associated with the pathogenesis of sJIA. Based on these results, four proteins (leucine aminopeptidase 3; LAP3, guanylate-binding protein 1; GBP1, Heme oxygenase 1; HMOX1, and bone morphogenetic protein 10; BMP10), which exhibit high fold changes during the active phase or which might be core proteins in the functional network were selected as candidate biomarkers. These proteins may be clinically useful for diagnostic and therapeutic purposes and might help determine the pathogenesis of the disease.