Singer I I, Scott S, Kawka D W, Bayne E K, Weidner J R, Williams H R, Mumford R A, Lark M W, McDonnell J, Christen A J, Moore V L, Mudgett J S, Visco D M
Department of Inflammation Research, Merck Research Labs., Merck & Co., Inc., Rahway, New Jersey 07065, USA.
Osteoarthritis Cartilage. 1997 Nov;5(6):407-18. doi: 10.1016/s1063-4584(97)80045-3.
To analyze the roles of two classes of proteinases, 'aggrecanase', and matrix metalloproteinases (MMPs), in chondrodestruction during murine collagen-induced arthritis (CIA).
Generation of the 'aggrecanase' neo-epitope (NITEGE373), and the MMP neo-epitope (VDIPEN341) within aggrecan was studied by immunoperoxidase microscopy using specific anti-peptide antibodies in normal and stromelysin-1 (SLN-1) deficient knockout mice with CIA.
High levels of NITEGE373 and VDIPEN341 neo-epitopes were observed in foci within CIA paw articular cartilage exhibiting depletion of glycosaminoglycans, in advance of significant cartilage erosion. The highest concentrations of NITEGE373 and VDIPEN341 labeling were observed and often co-distributed in the chondrocyte pericellular matrix, suggesting that stimulated chondrocytes can synthesize and/or activate both enzymes. Other regions of the cartilage frequently exhibited either NITEGE373 or VDIPEN341 labeling, but not both neo-epitopes simultaneously, suggesting that 'aggrecanase' and MMP cleavages of aggrecan may be generated independently. No detectable differences were observed in expression or distribution of either neo-epitope in SLN-1 knockout versus wild-type mice. In addition, in vitro digestion of joint sections with SLN-1 did not alter the expression of cartilage NITEGE373, while markedly increasing VDIPEN341 labeling. Peripheral nerves and brains of naive mice also exhibited intense anti-NITEGE373 labeling.
These data indicate that NITEGE373 and VDIPEN341 aggrecan neo-epitopes are sensitive and specific markers of early joint pathology, and are consistent with the hypothesis that SLN-1 does not have 'aggrecanase' activity, and that 'aggrecanase' is distinct from the MMPs which cleave aggrecan at the MMP site.
分析两类蛋白酶，即“聚集蛋白聚糖酶”和基质金属蛋白酶（MMPs）在小鼠胶原诱导性关节炎（CIA）软骨破坏过程中的作用。
在正常及基质溶解素-1（SLN-1）缺陷型基因敲除的CIA小鼠中，使用特异性抗肽抗体，通过免疫过氧化物酶显微镜技术研究聚集蛋白聚糖中“聚集蛋白聚糖酶”新表位（NITEGE373）和MMP新表位（VDIPEN341）的产生情况。
在CIA爪关节软骨中出现糖胺聚糖耗竭的病灶内，在明显的软骨侵蚀之前，观察到高水平的NITEGE373和VDIPEN341新表位。观察到NITEGE373和VDIPEN341标记的最高浓度，且常共同分布于软骨细胞周围基质中，提示受刺激的软骨细胞可合成和/或激活这两种酶。软骨的其他区域常仅表现出NITEGE373或VDIPEN341标记，而非同时出现两种新表位，提示聚集蛋白聚糖的“聚集蛋白聚糖酶”和MMP切割可能是独立产生的。在SLN-1基因敲除小鼠与野生型小鼠中，未观察到任一新表位的表达或分布有可检测到的差异。此外，用SLN-1对关节切片进行体外消化，并未改变软骨NITEGE373的表达，却显著增加了VDIPEN341标记。未接触过抗原的小鼠的外周神经和大脑也表现出强烈的抗NITEGE373标记。
这些数据表明，NITEGE373和VDIPEN341聚集蛋白聚糖新表位是早期关节病理的敏感且特异的标志物，并且与以下假说一致：SLN-1不具有“聚集蛋白聚糖酶”活性，且“聚集蛋白聚糖酶”不同于在MMP位点切割聚集蛋白聚糖的MMPs。
