LDL receptor-related protein mediates uptake of aggregated LDL in human vascular smooth muscle cells
LDL receptor-related protein mediates uptake of aggregated LDL in human vascular smooth muscle cells
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DOI：
10.1161/01.atv.20.6.1572
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发表时间：
2000-06-01
影响因子：
8.7
通讯作者：
Badimon, L
中科院分区：
文献类型：
--
作者：
Llorente-Cortés, V;Martínez-González, J;Badimon, L
泡沫细胞的形成是动脉粥样硬化病变发生和发展的关键事件。我们之前已经报道，血管平滑肌细胞(VSMCs)内化聚集的低密度脂蛋白(AgLDL)会在这些细胞中产生胆固醇酯(CE)积聚。本研究的目的是分析低密度脂蛋白受体相关蛋白(LRP)是否介导VSMCs摄取agLDL。首先，免疫细胞化学和抗Lrp抗体荧光显微镜分析表明，Lrp在VSMC中高表达，荧光1，1‘-dioctadecyl-3，3，3’，3‘-tetramethylindocarbocycine标记的AgLDL和抗lrp抗体的共聚焦显微镜分析显示两者共存。第二种方法是分析LRP配体对agLDL内化的影响；乳铁蛋白通过损害agLDL结合而强烈抑制agLDL的CE聚集(25mUg/mL时为85.0+/-5.7%)。与抗LRP抗体共孵育后，低密度脂蛋白诱导的CE积累量呈剂量依赖性减少(从12.5微克/毫升时的20%下降到50微克/毫升时的80%)。第三种方法是评价反义LRP寡核苷酸是否能够阻断agLDL内化。用5 mU·mol/L反义LRP寡核苷酸处理VSMC，可使agLDL诱导的CE积聚减少84%。总之，这些来自免疫学、生化和分子干预的结果表明，LRP介导了人VSMCs中agLDL的结合和内化。由于LRP在VSMC中高表达，而摄取1个低密度脂蛋白相当于数百个低密度脂蛋白颗粒的沉积，因此通过LRP摄取agLDL可能对VSMC中的脂质沉积具有至关重要的作用。
Foam cell formation is a key event in the onset and progression of atherosclerotic lesions. We have previously reported that internalization of aggregated low density lipoproteins (agLDLs) by vascular smooth muscle cells (VSMCs) produces cholesteryl ester (CE) accumulation in these cells. The aim of this study was to analyze whether the low density lipoprotein receptor-related protein (LRP) mediates the uptake of agLDL by VSMCs. First, immunocytochemistry and fluorescence microscopic analysis with the use of anti-LRP antibodies indicated that there was a high expression of LRP in VSMCs, Confocal microscopic analysis with the use of agLDLs labeled with fluorochrome 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocycine and anti-LRP antibodies showed the colocalization of agLDL and LRP. The second approach was to analyze the effect of LRP ligands on agLDL internalization; lactoferrin strongly inhibited CE accumulation from agLDLs (85.0+/-5.7% at 25 mu g/mL) by impairing agLDL binding. Coincubation of agLDL with anti-LRP antibodies decreased in a dose-dependent manner agLDL-derived CE accumulation (from 20% at 12.5 mu g/mL to 80% at 50 mu g/mL). The third approach was to evaluate whether antisense LRP oligodeoxynucleotides were able to block agLDL internalization. Treatment of VSMCs with 5 mu mol/L antisense LRP oligodeoxynucleotides reduced agLDL-derived CE accumulation by 84+/-2%. In conclusion, these results from immunologic, biochemical, and molecular interventions demonstrate that LRP mediates the binding and internalization of agLDL in human VSMCs. Because LRP is highly expressed in VSMCs and the uptake of 1 LDL aggregate amounts to the deposition of several hundreds of LDL particles, the uptake of agLDL through LRP could have a crucial role for lipid deposition in VSMCs.