Shimizu Teruki, Tani Kenji, Hase Kayoko, Ogawa Hirohisa, Huang Luping, Shinomiya Fumio, Sone Saburo
Tokushima University, Tokushima City, Japan.
Arthritis Rheum. 2002 Sep;46(9):2330-8. doi: 10.1002/art.10517.
We previously showed that CD13/aminopeptidase N (EC 3.4.11.2) induces chemotactic migration of T lymphocytes by its enzymatic activity. In this study, we examined the role of CD13/aminopeptidase N in lymphocyte involvement in rheumatoid arthritis (RA).
Synovial fluids were obtained from 27 RA patients and 6 osteoarthritis (OA) patients. Synovial tissue specimens were obtained from 3 RA patients and 3 OA patients. Protease activity of aminopeptidase in synovial fluids and synovial fibroblasts was assayed fluorometrically using the specific substrate. Expression of CD13/aminopeptidase N in synovial fibroblasts was determined by flow cytometry analyses, Western blotting, and reverse transcriptase-polymerase chain reaction (RT-PCR).
The mean value of aminopeptidase activity in synovial fluid samples from RA patients was significantly higher than that in samples from OA patients. Increased enzymatic activity of aminopeptidase was detected on synovial fibroblasts from RA patients compared with those from OA patients. Flow cytometry showed that the expression of CD13/aminopeptidase N on synovial fibroblasts from RA patients was higher than the expression on synovial fibroblasts from OA patients, and Western blots and RT-PCR showed that synovial fibroblasts from RA patients contained a greater amount of CD13/aminopeptidase N. The activity of CD13/aminopeptidase N correlated significantly with lymphocyte counts in synovial fluids from RA patients. Synovial fluids from RA patients in which high aminopeptidase activity was detected contained considerable chemotactic activity for lymphocytes, and bestatin, a specific inhibitor of aminopeptidases, partially inhibited the chemotactic activity.
CD13/aminopeptidase N may participate in the mechanism of lymphocyte involvement in inflamed joints of RA patients as a lymphocyte chemoattractant.
我们之前表明，CD13/氨肽酶N（EC 3.4.11.2）通过其酶活性诱导T淋巴细胞的趋化性迁移。在本研究中，我们检测了CD13/氨肽酶N在类风湿关节炎（RA）淋巴细胞参与过程中的作用。
从27例RA患者和6例骨关节炎（OA）患者中获取滑液。从3例RA患者和3例OA患者中获取滑膜组织标本。使用特异性底物通过荧光法测定滑液和滑膜成纤维细胞中氨肽酶的蛋白酶活性。通过流式细胞术分析、蛋白质印迹法和逆转录聚合酶链反应（RT-PCR）测定滑膜成纤维细胞中CD13/氨肽酶N的表达。
RA患者滑液样本中氨肽酶活性的平均值显著高于OA患者样本中的平均值。与OA患者的滑膜成纤维细胞相比，在RA患者的滑膜成纤维细胞中检测到氨肽酶的酶活性增加。流式细胞术显示，RA患者滑膜成纤维细胞上CD13/氨肽酶N的表达高于OA患者滑膜成纤维细胞上的表达，蛋白质印迹法和RT-PCR显示，RA患者的滑膜成纤维细胞含有更多的CD13/氨肽酶N。CD13/氨肽酶N的活性与RA患者滑液中的淋巴细胞计数显著相关。检测到高氨肽酶活性的RA患者滑液对淋巴细胞具有相当大的趋化活性，氨肽酶的特异性抑制剂贝司他汀部分抑制了趋化活性。
CD13/氨肽酶N可能作为淋巴细胞趋化因子参与RA患者炎症关节中淋巴细胞参与的机制。
