The rheumatoid arthritis synovial fluid citrullinome reveals novel citrullinated epitopes in apolipoprotein E, myeloid nuclear differentiation antigen, and ß-actin
The rheumatoid arthritis synovial fluid citrullinome reveals novel citrullinated epitopes in apolipoprotein E, myeloid nuclear differentiation antigen, and ß-actin
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DOI：
10.1002/art.37720
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发表时间：
2013-01-01
影响因子：
--
通讯作者：
Pruijn, Ger J. M.
中科院分区：
文献类型：
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作者：
van Beers, Joyce J. B. C.;Schwarte, Carla M.;Pruijn, Ger J. M.
目的建立类风湿关节炎（RA）患者滑膜中瓜氨酸化蛋白的目录，并探讨其与RA抗瓜氨酸化蛋白抗体应答的关系。方法从类风湿关节炎患者关节液中分离多肽，并对其进行质谱鉴定。三种蛋白质（载脂蛋白E [Apo E]，髓细胞核分化抗原[MNDA]和β-肌动蛋白）进行了更详细的研究，使用免疫沉淀和蛋白质印迹。通过酶联免疫吸附试验（ELISA）研究了来自RA患者血清、来自其他疾病患者血清和来自健康对照受试者血清中的合成肽的自身抗体的存在。结果RA滑液样品显示几种不同的瓜氨酸化蛋白模式。使用质谱法，鉴定了192种蛋白质（的片段），包括53种瓜氨酸化蛋白质，其中一些含有多个瓜氨酸化残基。除了之前报道的RA滑液中的瓜氨酸化蛋白（例如，波形蛋白和纤维蛋白原），鉴定了一系列新的瓜氨酸化蛋白，包括Apo E、MNDA、β-肌动蛋白和亲环素A。免疫沉淀实验证实了Apo E和MNDA的瓜氨酸。ELISA证实了载脂蛋白E、MNDA和β-肌动蛋白中存在自身反应性瓜氨酸化表位。结论类风湿关节炎患者关节滑液中含有大量的瓜氨酸化蛋白。瓜氨酸化Apo E、MNDA和β-肌动蛋白是在RA滑液中鉴定的新抗原，并且在RA中只有有限数量的瓜氨酸化表位被免疫系统靶向。
Objective To generate a catalog of citrullinated proteins that are present in the synovia of patients with rheumatoid arthritis (RA) and to elucidate their relevance for the anticitrullinated protein antibody response in RA. Methods Polypeptides isolated from the synovial fluid of patients with RA were identified by mass spectrometry. Three proteins (apolipoprotein E [Apo E], myeloid nuclear differentiation antigen [MNDA], and beta-actin) were studied in more detail, using immunoprecipitation and Western blotting. The presence of autoantibodies to synthetic peptides derived from these proteins in sera from patients with RA, sera from patients with other diseases, and sera from healthy control subjects was studied by enzyme-linked immunosorbent assay (ELISA). Results RA synovial fluid samples displayed several distinct patterns of citrullinated proteins. Using mass spectrometry, (fragments of) 192 proteins were identified, including 53 citrullinated proteins, some of which contained multiple citrullinated residues. In addition to previously reported citrullinated proteins in RA synovia (e.g., vimentin and fibrinogen), a series of novel citrullinated proteins, including Apo E, MNDA, beta-actin, and cyclophilin A, was identified. Immunoprecipitation experiments confirmed the citrullination of Apo E and MNDA. ELISAs demonstrated the presence of autoreactive citrullinated epitopes in Apo E, MNDA, and beta-actin. Conclusion Synovial fluid samples from the inflamed joints of patients with RA contain many citrullinated proteins. Citrullinated Apo E, MNDA, and beta-actin are novel antigens identified in RA synovial fluid, and only a limited number of their citrullinated epitopes are targeted by the immune system in RA.