BACKGROUND To understand the roles of serum exosomes in rheumatoid arthritis (RA), we comprehensively investigated the protein profiles of serum exosomes in patients with RA. METHODS Exosomes were isolated from serum samples obtained from 33 patients (12 with active RA [aRA], 11 with inactive RA [iRA], 10 with osteoarthritis [OA]) and 10 healthy donors (HLs). Proteins extracted from the exosomes were separated by two-dimensional differential gel electrophoresis (2D-DIGE) and identified by mass spectrometry. RESULTS In total, 204 protein spots were detected by 2D-DIGE. In the aRA, iRA, and OA groups, 24, 5, and 7 spots showed approximately ≥ ±1.3-fold intensity differences compared with the HL group, respectively. We were able to identify proteins in six protein spots. Among them, the protein spot identified as Toll-like receptor 3 (TLR3) showed approximately 6-fold higher intensity in the aRA group than in the other groups. CONCLUSIONS Patients with active RA possessed considerably different protein profiles of serum exosomes from patients with iRA, patients with OA, and healthy donors. The unique protein profile of serum exosomes, such as the possession of abundant TLR3 fragments, may reflect the pathophysiology of active RA.

中文翻译：

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类风湿性关节炎中血清衍生外泌体的蛋白质组学分析。

背景为了解血清外泌体在类风湿关节炎 (RA) 中的作用，我们全面研究了 RA 患者血清外泌体的蛋白质谱。方法 从 33 名患者（12 名活动性 RA [aRA]、11 名非活动性 RA [iRA]、10 名骨关节炎 [OA]）和 10 名健康供体 (HLs) 的血清样本中分离外泌体。从外泌体中提取的蛋白质通过二维差示凝胶电泳 (2D-DIGE) 分离并通过质谱鉴定。结果 2D-DIGE 共检测到 204 个蛋白点。在 aRA、iRA 和 OA 组中，与 HL 组相比，24、5 和 7 个点的强度差异分别约为 ≥ ±1.3 倍。我们能够识别六个蛋白质点中的蛋白质。其中，被鉴定为 Toll 样受体 3 (TLR3) 的蛋白点在 aRA 组中显示出比其他组高约 6 倍的强度。结论 活动性 RA 患者的血清外泌体蛋白谱与 iRA 患者、OA 患者和健康供体有很大不同。血清外泌体独特的蛋白质谱，例如拥有丰富的 TLR3 片段，可能反映了活动性 RA 的病理生理学。