Aggrecan is degraded by matrix metalloproteinases in human arthritis - Evidence that matrix metalloproteinase and aggrecanase activities can be independent
Aggrecan is degraded by matrix metalloproteinases in human arthritis - Evidence that matrix metalloproteinase and aggrecanase activities can be independent
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DOI：
10.1172/jci119040
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发表时间：
1996-11-15
影响因子：
15.9
通讯作者：
Maciewicz, RA
中科院分区：
文献类型：
--
作者：
Fosang, AJ;Last, K;Maciewicz, RA
聚集蛋白聚糖的蛋白水解降解是关节炎病理学的标志，然而软骨中负责这种降解的酶的身份是未知的。先前的研究表明基质金属蛋白酶（MMP）可能参与其中，但没有明确的证据表明它们在人类关节炎中聚集蛋白聚糖的蛋白水解中的直接作用。我们现在明确地表明，来自MMP特异性作用的聚集蛋白聚糖片段可以在炎性和非炎性关节炎患者的滑液中检测到，用新表位单克隆抗体AF-28检测NH 2-末端序列F（342）FGVG....滑液MMP片段具有低浮力密度，并且仅分布在氯化铯密度梯度的顶部，表明这些片段缺乏硫酸软骨素链。滑液聚集蛋白聚糖片段的AF-28免疫印迹揭示了30-50 kD的小AF-28片段的群体。基于它们相对于MMP-8消化物的表征产物的大小（Fosang，A. J.，K.最后，P.加德纳，D. C.杰克逊和L.布朗1995，Biochem.J.310：337-343），这些AF-28片段来源于在或接近于... ITEGE（373）down arrow ARGSV.聚集蛋白聚糖酶位点。用多克隆抗ITEGE抗血清进行免疫检测，发现这些片段缺乏特异性。ITEGE（374）COOH末端，因此不是聚集蛋白聚糖酶作用的产物，相同的液体样品含有一个宽的68-90-kD G1片段，该片段含有COOH-末端，... ITEGE（374）新表位。结果表明，在某些情况下，尽管广泛的核心蛋白水解，聚集蛋白聚糖分子可能被切割的基质金属蛋白酶或聚集蛋白聚糖酶的interglobular域，但不是两者兼而有之。
Proteolytic degradation of aggrecan is a hallmark of the pathology of arthritis, yet the identity of the enzyme(s) in cartilage responsible for this degradation is unknown, Previous studies have suggested that the matrix metalloproteinases (MMPs) may be involved but there has been no definitive evidence for their direct action in the proteolysis of aggrecan in human arthritis,We now show unequivocally that aggrecan fragments derived from the specific action of MMPs can be detected in synovial fluids from patients with both inflammatory and noninflammatory arthritis, with a neoepitope monoclonal antibody AF-28 that detects the NH2-terminal sequence F(342)FGVG.... The synovial fluid MMP fragments were of low buoyant density and distributed exclusively at the top of cesium chloride density gradients, suggesting that these fragments lacked chondroitin sulfate chains, AF-28 immunoblotting of synovial fluid aggrecan fragments revealed a population of small AF-28 fragments of 30-50 kD. Based on their size relative to characterized products of an MMP-8 digest (Fosang, A.J., K. Last, P. Gardiner, D.C. Jackson, and L. Brown. 1995, Biochem. J. 310:337-343), these AF-28 fragments were derived from proteinase cleavage at, or near, the... ITEGE(373) down arrow ARGSV... aggrecanase site. Immunodetection with polyclonal anti-ITEGE antiserum revealed that these fragments lacked the... ITEGE(374) COOH terminus and were not therefore products of aggrecanase action, The same fluid samples contained a broad 68-90-kD G1 fragment that contained the COOH-terminal ...ITEGE(374) neoepitope. The results suggest that in some circumstances, despite extensive proteolysis of the core protein, aggrecan molecules may be cleaved by MMPs or aggrecanase in the interglobular domain, but not both.