The inhibition of antithrombin by peptidylarginine deiminase 4 may contribute to pathogenesis of rheumatoid arthritis
The inhibition of antithrombin by peptidylarginine deiminase 4 may contribute to pathogenesis of rheumatoid arthritis
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DOI：
10.1093/rheumatology/keh473
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发表时间：
2005-03-01
期刊：
影响因子：
5.5
通讯作者：
Yamamoto, K
中科院分区：
文献类型：
--
作者：
Chang, X;Yamada, R;Yamamoto, K
目标。肽精氨酸脱亚胺酶4 （PADI4）基因已被发现与类风湿关节炎（RA）密切相关。肽精氨酸脱亚胺酶（PADI）催化翻译后的肽精氨酸修饰成瓜氨酸，这一反应被称为瓜氨酸化。据报道，从兔子肌肉中提取的PADI含有瓜氨酸抗凝血酶，这是一种主要的血浆凝血酶抑制剂。已知凝血酶可诱导血管生成、纤维蛋白形成和炎症，这是类风湿性关节炎关节的主要事件。在此，我们研究了人PADI4是否通过催化抗凝血酶瓜氨酸化来抑制抗凝血酶，以及该酶如何参与RA的发病机制。将抗凝血酶与重组PADI4蛋白孵育，通过降低抗凝血酶抑制活性来测定抗凝血酶的失活。采用western blotting和酶联免疫吸附试验（ELISA）检测抗凝血酶的瓜氨酸化。采用夹心elisa法检测RA血浆中瓜氨酸化水平、抗凝血酶活性及浓度。抗凝血酶与PADI4孵育导致凝血酶抑制活性丧失和抗凝血酶瓜氨酸化。RA患者血浆瓜氨酸化抗凝血酶水平高于非关节炎患者和健康人群。结果表明PADI4可通过瓜氨酸化作用使抗凝血酶失活。RA滑膜中PADI4的异常表达或激活可能是RA血浆中瓜氨酸化抗凝血酶水平升高的原因。RA滑膜局部抑制抗凝血酶活性可能导致血管生成过多、纤维蛋白沉积和组织炎症。
Objective. The gene for peptidylarginine deiminase 4 (PADI4) has been found to be closely associated with rheumatoid arthritis (RA). Peptidylarginine deiminase (PADI) catalyses the post-translational modification of peptidylarginine to citrulline, a reaction known as citrullination. PADI extracted from rabbit muscle has been reported to citrullinate antithrombin, a principal plasma inhibitor of thrombin. Thrombin is known to induce angiogenesis, fibrin formation and inflammation, the primary events of the RA joint. Here, we investigate whether human PADI4 can inhibit antithrombin by catalysing antithrombin citrullination and how the enzyme is involved in RA pathogenesis.Methods. Antithrombin was incubated with recombinant PADI4 protein, and the inactivation of antithrombin was determined by reduction of its thrombin-inhibiting activity. Citrullination of antithrombin was detected by western blotting and enzyme-linked immunosorbent assay (ELISA). In addition, the citrullination level, activity and concentration of antithrombin in RA plasma were investigated by sandwich ELISA.Results. Incubation of antithrombin with PADI4 resulted in loss of thrombin-inhibitory activity and in citrullination of antithrombin. RA plasma showed higher levels of citrullinated antithrombin than controls with non-arthritis disease and healthy individuals.Conclusion. The results indicate that PADI4 could inactivate antithrombin through citrullination. The abnormal expression or activation of PADI4 in RA synovium is suggested to be responsible for the high level of citrullinated antithrombin in RA plasma. Local inhibition of antithrombin activity in RA synovium might lead to the excessive angiogenesis, fibrin deposition and inflammation of the tissue.