Expression of cathepsin K is regulated by shear stress in cultured endothelial cells and is increased in endothelium in human atherosclerosis
Expression of cathepsin K is regulated by shear stress in cultured endothelial cells and is increased in endothelium in human atherosclerosis
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DOI：
10.1152/ajpheart.00954.2006
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发表时间：
2007-03-01
影响因子：
4.8
通讯作者：
Jo, Hanjoong
中科院分区：
文献类型：
--
作者：
Platt, Manu O.;Ankeny, Randall F.;Jo, Hanjoong
组织蛋白是溶酶体半胱氨酸蛋白酶，参与血管重塑和动脉粥样硬化。在小鼠中，组织蛋白酶S和K的基因敲除已显示出减少动脉粥样硬化的作用，尽管其分子机制尚不清楚。由于动脉粥样硬化主要发生在血流受扰条件下的动脉，我们假设剪切力可以调节血管内皮细胞中组织蛋白酶K的表达和活性。小鼠主动脉内皮细胞(MAEC)暴露于致动脉粥样硬化的振荡剪切力(OS，+/-5dyn/cm(2))1d后，其组织蛋白酶K的表达和活性显著高于动脉粥样硬化保护的单向层流剪切力(LS，15dyn/cm(2)，1d)。Western印迹和活性部位标记研究表明，在OS作用下的MAEC条件培养液中有活性的成熟形式的组织蛋白酶K，而在LS条件培养液中则没有。在功能上，暴露于OS的MAEC的弹性蛋白酶和明胶酶活性显著高于LS。用小干扰(Si)RNA抑制组织蛋白酶K后，OS依赖的弹性蛋白酶和明胶酶活性显著降低，但不受非沉默siRNA对照的影响，这表明组织蛋白酶K是一种剪切敏感的蛋白酶。此外，免疫组织化学分析显示，血管内皮细胞中组织蛋白酶K的表达水平与弹性膜完整性呈正相关。这些发现表明，组织蛋白酶K是一种机械敏感的细胞外基质蛋白酶，反过来可能参与动脉壁重建和动脉粥样硬化。
Cathepsins, the lysosomal cysteine proteases, are involved in vascular remodeling and atherosclerosis. Genetic knockout of cathepsins S and K in mice has shown to reduce atherosclerosis, although the molecular mechanisms remain unclear. Because atherosclerosis preferentially occurs in arteries exposed to disturbed flow conditions, we hypothesized that shear stress would regulate cathepsin K expression and activity in endothelial cells. Mouse aortic endothelial cells ( MAEC) exposed to proatherogenic oscillatory shear ( OS, +/- 5 dyn/ cm(2) for 1 day) showed significantly higher cathepsin K expression and activity than that of atheroprotective, unidirectional laminar shear stress ( LS, 15 dyn/ cm(2) for 1 day). Western blot and active- site labeling studies showed an active, mature form of cathepsin K in the conditioned medium of MAEC exposed to OS but not in that of LS. Functionally, MAEC exposed to OS significantly increased elastase and gelatinase activity above that of LS. The OS- dependent elastase and gelatinase activities were significantly reduced by knocking down cathepsin K with small- interfering ( si) RNA, but not by a nonsilencing siRNA control, suggesting that cathepsin K is a shear- sensitive protease. In addition, immunohistochemical analysis of atherosclerotic human coronary arteries showed a positive correlation between the cathepsin K expression levels in endothelium and elastic lamina integrity. These findings suggest that cathepsin K is a mechanosensitive, extracellular matrix protease that, in turn, may be involved in arterial wall remodeling and atherosclerosis.