Oxidized LDL Receptor LOX-1 Binds to C-Reactive Protein and Mediates Its Vascular Effects
Oxidized LDL Receptor LOX-1 Binds to C-Reactive Protein and Mediates Its Vascular Effects
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DOI：
10.1373/clinchem.2008.119750
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发表时间：
2009-02-01
影响因子：
9.3
通讯作者：
Sawamura, Tatsuya
中科院分区：
文献类型：
--
作者：
Fujita, Yoshiko;Kakino, Akemi;Sawamura, Tatsuya
背景：C - 反应蛋白（CRP）对血管内皮细胞具有生物活性。这种活性可能促进动脉粥样硬化血栓形成，但该活性的作用仍存在争议。凝集素样氧化低密度脂蛋白受体 - 1（LOX - 1）是内皮细胞上的氧化低密度脂蛋白受体，参与氧化低密度脂蛋白诱导的内皮功能障碍。
方法：我们使用激光共聚焦显微镜检查，并通过荧光细胞图像分析来量化荧光标记的CRP与表达LOX - 1的细胞的结合。然后我们在无细胞系统中检测未标记的CRP与重组人LOX - 1的结合。将针对LOX - 1的小干扰RNA（siRNAs）应用于培养的牛内皮细胞，以分析LOX - 1在原代细胞中的作用。为了观察其在体内的作用，我们在易卒中型自发性高血压（SHR - SP）大鼠皮内注射CRP，并分析血管通透性。
结果：CRP与表达LOX - 1的细胞结合，同时诱导LOX - 1表达。CRP与细胞系和重组LOX - 1呈剂量依赖性结合，在0.3 mg/L CRP浓度时可检测到显著结合。结合的K - d值计算为1.6×10⁻⁷ mol/L。针对LOX - 1的siRNA显著抑制荧光标记的CRP与内皮细胞的结合，而对照RNA则无此作用。在体内，皮内注射CRP可诱导SHR - SP大鼠血管渗出伊文思蓝染料，在这些大鼠中LOX - 1的表达显著增强。抗LOX - 1抗体显著抑制血管通透性。
结论：CRP和氧化低密度脂蛋白受体LOX - 1直接相互作用。缺血性心脏病的两个危险因素，CRP和氧化低密度脂蛋白，共享一个共同的分子LOX - 1作为它们的受体。（C）2008美国临床化学协会
BACKGROUND: C-reactive protein (CRP) exerts biological activity on vascular endothelial cells. This activity may promote atherothrombosis, but the effects of this activity are still controversial. Lectin-like oxidized LDL receptor-1 (LOX-1), the oxidized LDL receptor on endothelial cells, is involved in endothelial dysfunction induced by oxidized LDL.METHODS: We used laser confocal microscopy to examine and fluorescence cell image analysis to quantify the binding of fluorescently labeled CRP to cells expressing LOX-1. We then examined the binding of unlabeled CRP to recombinant human LOX-1 in a cell-free system. Small interfering RNAs (siRNAs) against LOX-1 were applied to cultured bovine endothelial cells to analyze the role of LOX-1 in native cells. To observe its in vivo effects, we injected CRP intradermally in stroke-prone spontaneously hypertensive (SHR-SP) rats and analyzed vascular permeability.RESULTS: CRP bound to LOX-1-expressing, cells in parallel with the induction of LOX-1 expression. CRP dose-dependently bound to the cell line and recombinant LOX-1, with significant binding detected at 0.3 mg/L CRI) concentration. The K-d value of the binding was calculated to be 1.6 X 10(-7) mol/L. siRNA against LOX-1 significantly inhibited the binding of fluorescently labeled CRP to the endothelial cells, whereas control RNA did not. In vivo, intradermal injection of CRP-induced vascular exudation of Evans blue dye in SHR-SP rats, in which expression of LOX-1 is greatly enhanced. Anti-LOX-1 antibody significantly suppressed vascular permeability.CONCLUSIONS: CRP and oxidized LDL-receptor LOX-1 directly interact with each other. Two risk factors for ischemic heart diseases, CRP and oxidized LDL, share a common molecule LOX-1, as their receptor. (C) 2008 American Association for Clinical Chemistry