Molecular Pathology of Cartilage destruction in Rheumatoid Arthritis

细胞外基质(ECM)的降解是类风湿关节炎(RA)关节软骨破坏的重要环节，基质金属蛋白酶(MMP)基因家族成员参与了ECM的降解。在目前的研究中，我们表征了一些基质金属蛋白酶的生化性质，并研究了它们在RA关节软骨破坏中的作用。此外，还与制药公司合作开发了合成的基质金属蛋白酶抑制剂和金属蛋白酶组织抑制因子3(TIMP-3)诱导的药物。主要研究结果如下：(1)。在TIMP-2存在的情况下，TIMP-2可加速膜型基质金属蛋白酶介导的原基质金属蛋白酶-2(MT1-MMP)的活化，因此TIMP-2被认为是有效激活细胞膜上的原基质金属蛋白酶-2所必需的。我们还证明了MT1-MMP在球间结构域的三个位置上裂解aggrecan，而MT3-MMP降解ECM成分，如III型胶原和aggrecan。O…另外，TIMP-1不能抑制MT1-MMPs和MT3-MMPs的活性。刀豆蛋白A处理的肿瘤细胞膜上可见MT-MMPs脱落。在RA滑膜组织中，ProMMP2被有效地激活，其活化率与MT1、2、3MMPs中MT1-MMPs的表达水平直接相关。在RA滑膜衬里细胞中有MT1-MMPs的表达，并通过原位酶谱检测衬里细胞层的明胶溶解活性。用双抗体夹心酶联免疫吸附试验检测滑液中MMP1、2、3、7、8、9、13和TIMP-1、2的稳态水平时，RA组的MMP1、2、3、8、9和TIMP-1水平明显高于OA组。类风湿关节炎患者外周血中基质金属蛋白酶活性明显高于骨性关节炎患者，且与基质金属蛋白酶/组织金属蛋白酶的摩尔比呈正相关，提示二者之间存在着有利于蛋白水解酶的失衡。通过与一家制药公司的合作，我们开发了对MT1-MMP更具选择性的合成抑制剂，我们还证明了多硫酸戊聚糖通过转录后水平刺激RA滑膜成纤维细胞产生TIMP-3。较少

Degradation of the extracellular matrix (ECM) is an essential step to the destruction of articular cartilage in rheumatoid athritis (RA), and members of the matrix metalloproteinase (MMP) gene family are involved in the degradation. In the present studies, we characterized the biochemical properties of some MMP species and examined their functions in the destruction of the cartilage in RA joints. In addition, synthetic MMP inhibitors and tissue inhibitor of metalloproteinases 3 (TIMP-3)-inducible drug were developed by collaboration with pharmaceutical companies. The major results are as follows:(1). Activation of proMMP-2 mediated by membrane-type1 MMP (MT1-MMP) was accelerated in the presence of TIMP-2, and thus TIMP-2 was considered to be essential to the efficient activation of proMMP-2 on the cell membranes. We also demonstrated that MT1-MMP cleaves aggrecan at three sites in the interglobular domain and MT3-MMP degrades the ECM components such as type III collagen and aggrecan. O … More n the other hand, the activities of MT1-MMP and MT3-MMP were not inhibited by TIMP-1. MT-MMP was shown to be shed from the cell membranes of tumor cells treated with concanvalin A.(2). ProMMP-2 was efficiently activated in RA synovial tissues and its activation ratio directly correlated with the expression levels of MT1-MMP among MT1, 2, 3-MMPs. MT1-MMP was expressed in the lining cells of RA synovial membrane and gelatinolytic activity was detected by in situ zymography in the lining cell layer.(3). When steady state levels of MMP-1, 2, 3, 7, 8, 9, 13 and TIMP-1, 2 in synovial fluids were assayed by sandwich enzyme immunoassays, the levels of MMP 1, 2, 3, 8, 9 and TIMP-1 were significantly higher in RA than in OA. The molar ratio was significantly higher in RA than in OA, and metalloproteinase activity was detected with a direct correlation to MMP/TIMP molar ratio, suggesting an imbalance in favor of proteinase.(4). By collaboration with a pharmaceutical company, we developed synthetic inhibitors more selective to MT1-MMP, We also demonstrated that pentosan polysulfate stimulates RA synovial fibroblasts to produce TIMP-3 by the posttranscriptional level. Less