Clinical and pathological significance of autoantibodies to calpastatin in rheumatoid arthritis

类风湿性关节炎中钙蛋白酶抑制剂自身抗体的临床和病理意义

• 批准号: 07670540
• 负责人: MIMORI Tsuneyo
• 金额: $ 1.54万
• 依托单位: Keio University School of Medicine
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07670540/
• 关键词: autoantibody; calpastatin; calpain; autoimmune disease; rheumatoid arthritis; proteinase; proteinase inhibitor; antigenic epitope

We found novel autoantibodies to calpastatin, natural inhibitor for calcium-dependent neutral proteinase (calpain), in patients with rheumatoid arthritis (RA). Since calpain is thought to be one of neutral proteinases that may be involved in joint destruction and inflammation process, the production of autoantibodies to its inhibitor protein, calpastatin, might be associated with pathogenic mechanisms of RA.In this study, we intended to elucidate 1) the clinical significance of autoantibodies ot calpastatin, 2) analysis of autoantigenic epitopes recognized by patient autoantibodies, and 3) the pathogenic role of anti-clpastatin antibodies.Autoantibodies to calpastatin in various rheumatic diseases were screened by immunoblotting using the fusion protein expressed from E.coli with a partial cDNA (RA-6) encoding the C-terminal 178 amino acids of human calpastatin. Anti-calpastatin antibodies were detected in 57% of patients with RA and were significantly more frequent than in SLE (27%), … More scleroderma (38%) and myositis (24%).Antigenic epitopes were analyzed by using an epitope library constructed by restriction enzyme-digested RA-6 cDNA that was subcloned into an expression vector. Autoantibodies from patient sera recognized a C-terminal region (C1 ; aa. 152-178) and a N-terminal region (C2 ; aa. 1-76), whereas a mouse monoclonal antibody (CSF3-3) recognized an entirely different region containing the calpain-binding site (B2 ; aa. 77-130) RA patients whose sera reacted with the Cl epitope represented a more progressed and severe state of arthritis than those not reacting with Cl.Anti-calpastatin antibodies were also detected in synovial fluids from RA patients who had anti-calpastatin in sera. IgG fractions from sera containing anti-calpastatin antibodies selectively blocked the function of calpastatin and recovered the proteolytic activity of calpain in dose-dependent manner. In contrast, IgG from normal sera or patient sera without anti-calpastatin antibodies did not recover the calpain activity.These results strongly suggest that the production of autoantibodies to calpastatin in patients with RA is not merely epiphenomenon but may be involved in pathogenic mechanisms by inhibiting the function of clpastatin and increasing the calpain activity in synovial tissue. Less

我们在类风湿关节炎（RA）患者中发现了新型钙蛋白酶抑制素（calpastatin）自身抗体，钙蛋白酶抑制素是钙依赖性中性蛋白酶（calpain）的天然抑制剂。由于钙蛋白酶被认为是一种中性蛋白酶，可能参与关节破坏和炎症过程，其抑制蛋白calpastatin自身抗体的产生可能与RA的发病机制有关。本研究旨在阐明1）calpastatin自身抗体的临床意义，2）分析患者自身抗体识别的自身抗原表位，3）抗钙蛋白酶抑制蛋白抗体的致病作用：用大肠杆菌表达的含人钙蛋白酶抑制蛋白C端178个氨基酸的部分cDNA（RA-6）的融合蛋白，用免疫印迹法筛选各种风湿性疾病中抗钙蛋白酶抑制蛋白的自身抗体。57%的RA患者检测到抗钙蛋白酶抑制蛋白抗体，其频率显著高于SLE患者（27%）， ...更多信息 将RA-6 cDNA亚克隆到表达载体中，构建表位文库，分析RA-6的抗原表位。来自患者血清的自身抗体识别C-末端区域（C1 ; aa. 152-178）和N-末端区域（C2 ; aa. 1-76），而小鼠单克隆抗体（CSF 3 -3）识别含有钙蛋白酶结合位点的完全不同的区域（B2 ; aa. 77-130）血清与Cl表位反应的RA患者比不与Cl反应的RA患者代表更进展和更严重的关节炎状态。在血清中具有抗钙蛋白酶抑制蛋白的RA患者的滑液中也检测到抗钙蛋白酶抑制蛋白抗体。含有抗钙蛋白酶抑制蛋白抗体的血清中的IgG组分选择性地阻断钙蛋白酶抑制蛋白的功能，并以剂量依赖性方式恢复钙蛋白酶的蛋白水解活性。与此相反，IgG从正常血清或患者血清中没有抗calpastatin抗体没有恢复calpain活性。这些结果强烈表明，在RA患者的calpastatin自身抗体的产生不仅是附带现象，但可能参与致病机制，通过抑制clpastatin的功能，增加calpain活性在滑膜组织。少

项目成果

Nojima T, Mimori T et al: "Detection of autoantibodies in patients with rheumatoid arthritis." Jpn J Rheumatol. (in press).

Nojima T、Mimori T 等人：“类风湿性关节炎患者自身抗体的检测”。

Mimori T: "Laboratory diagnosis of rheumatoid arthritis." Naika. 78 (2). 222-225 (1996)

Mimori T：“类风湿性关节炎的实验室诊断。”

三森経世: "慢性関節リウマチの臨床検査" 内科. 78. 222-225 (1996)

Tsuneyo Mimori：“类风湿性关节炎的临床检查”内科78。222-225（1996）。

Mimori T: "Update on structures targeted by the immune system in myositis" Current Opinion in Rheumatol. 8. 521-527 (1996)

Mimori T：“肌炎中免疫系统靶向结构的更新”《风湿病》的当前观点。

三森経世: "診断マーカーとしての自己抗体-使い方と読み方-" Medical Practice. 12. 1307-1311 (1995)

Keiyo Mimori：“自身抗体作为诊断标记 - 如何使用和阅读它们 -”《医疗实践》12. 1307-1311 (1995)。