Hypochlorous acid oxygenates the cysteine switch domain of pro-matrilysin (MMP-7). A mechanism for matrix metalloproteinase activation and atherosclerotic plaque rupture by myeloperoxidase.
Hypochlorous acid oxygenates the cysteine switch domain of pro-matrilysin (MMP-7). A mechanism for matrix metalloproteinase activation and atherosclerotic plaque rupture by myeloperoxidase.
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DOI：
10.1074/jbc.m106958200
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发表时间：
2001-11-02
影响因子：
4.8
通讯作者：
Heinecke, JW
中科院分区：
文献类型：
--
作者：
Fu, XY;Kassim, SY;Heinecke, JW
髓过氧化物酶利用过氧化氢(H_2O_2)生成次氯酸(HOCl)，这是一种有效的细胞毒性氧化剂。我们证明HOCl在体外调节基质金属蛋白酶-7(MMP7，matrilysin)的活性，提示这种氧化剂激活了动脉壁中的MMPs。事实上，在人类动脉粥样硬化病变中，基质金属蛋白酶-7和髓过氧化物酶共同定位于富含脂质的巨噬细胞。一个被称为半胱氨酸开关的高度保守的结构域被提出用来调节基质金属蛋白酶的活性。当我们展示一个模拟半胱氨酸切换到HOCl的合成肽时，高效液相分析显示，硫醇残基反应迅速，产生了近乎定量的产物。串联质谱分析确定产物为亚磺酸、磺酸和含有二硫键的二聚体。相反，该多肽与过氧化氢反应缓慢，唯一的产物是二硫化物。此外，HOCl可显著激活高水平表达于体内高脂巨噬细胞的前-基质金属蛋白酶-7。串联质谱分析表明，胰酶半胱氨酸转换区的硫醇残基已转化为亚磺酸。硫醇氧化与原-基质金属蛋白酶-7的自溶切割有关，强烈地表明氧合作用激活了潜伏酶。相反，过氧化氢不能氧化蛋白质中的硫醇残基或激活酶。因此，HOCl通过将半胱氨酸开关的硫醇残基转化为亚磺酸来激活Pro-MMP7。这一激活机制不同于已有的对基质金属蛋白酶原酶的蛋白水解性裂解。我们的观察增加了髓过氧化物酶产生的HOCl2促进了基质金属蛋白酶的激活，从而导致动脉壁斑块破裂的可能性。在多种炎症条件下，HOCl等氧化剂可能通过相同的机制调节基质金属蛋白酶的活性。
Myeloperoxidase uses hydrogen peroxide (H2O2) to generate hypochlorous acid (HOCl), a potent cytotoxic oxidant. We demonstrate that HOCl regulates the activity of matrix metalloproteinase-7 (MMP-7, matrilysin) in vitro, suggesting that this oxidant activates MMPs in the artery wall. Indeed, both MMP-7 and myeloperoxidase were colocalized to lipid-laden macrophages in human atherosclerotic lesions. A highly conserved domain called the cysteine switch has been proposed to regulate MMP activity. When we exposed a synthetic peptide that mimicked the cysteine switch to HOCl, HPLC analysis showed that the thiol residue reacted rapidly, generating a near-quantitative yield of products. Tandem mass spectrometric analysis identified the products as sulfinic acid, sulfonic acid, and a dimer containing a disulfide bridge. In contrast, the peptide reacted slowly with H2O2, and the only product was the disulfide. Moreover, HOCl markedly activated pro-MMP-7, an MMP expressed at high levels in lipid-laden macrophages in vivo. Tandem mass spectrometric analysis of trypsin digests revealed that the thiol residue of the enzyme's cysteine switch domain had been converted to sulfinic acid. Thiol oxidation was associated with autolytic cleavage of pro-MMP-7, strongly suggesting that oxygenation activates the latent enzyme. In contrast, H2O2 failed to oxidize the thiol residue of the protein or activate the enzyme. Thus, HOCl activates pro-MMP-7 by converting the thiol residue of the cysteine switch to sulfinic acid. This activation mechanism is distinct from the well-studied proteolytic cleavage of MMP pro-enzymes. Our observations raise the possibility that HOCl generated by myeloperoxidase contributes to MMP activation, and therefore to plaque rupture, in the artery wall. HOCl and other oxidants might regulate MMP activity by the same mechanism in a variety of inflammatory conditions.