[氧化型低密度脂蛋白通过凝集素样氧化型低密度脂蛋白受体介导对内皮祖细胞存活及活性的影响]
[Effects of oxidized low-density lipoprotein on endothelial progenitor cells survival and activity mediated by lectin-like oxidized low density lipoprotein receptor].
作者信息
Ma Feng-xia, Ren Qian, Han Zhong-chao
机构信息
State Key Laboratory of Experimental Hematology, Hospital of Blood Disease, Institute of Hematology, CAMS and PUMC, Tianjin 300020, China.
出版信息
Zhongguo Yi Xue Ke Xue Yuan Xue Bao. 2007 Jun;29(3):336-41.
OBJECTIVE
To investigate whether oxidized low-density lipoprotein (oxLDL) affects the survival and activity of endothelial progenitor cell (EPC) and whether the effects are mediated by lectin-like oxidized low-density lipoprotein receptor (LOX-1).
METHODS
CD34+ cells isolated from human umbilical blood were cultured in endothelial cell growth medium-2 (EGM-2). After 14 days of culture, some EPCs were stimulated with 10, 25, 50 microg/ml of oxLDL for 48 hours; some were preincubated with LOX-1 mAb, a blocking antibody of LOX-1, for 24 hours, then exposed to 50 microg/ml oxLDL for 48 hours; others without any further treatment were used as control. The survival of EPC and the ability of adhesion, migration, and tube formation were examined. The levels of LOX-1 protein and mRNA expression were also assayed.
RESULTS
Incubation with oxLDL at concentrations of 25 microg/ml or higher resulted in a dose-dependent increase of EPC apoptosis [25 microg/ml: (15.8 +/- 1.1.0%, 50 microg/ml: (18.8 +/- 2.0)% versus control: (9.0 +/- 1.2)%; P < 0.05]. Treated with oxLDL led to a significantly reduced migratry rate [25 microg/ml: (5.7 +/- 1.0)%, 50 microg/ml: (5.1 +/- 0.8)% versus control: (9.5 +/- 0.8)%; P < 0.05]. EPC treated with oxLDL showed a dose-dependent reduction of adhesion to fibronectin (25 Kg/ml: 33 +/- 2, 50 microg/ml: 30 +/- 3 versus control: 37 +/- 5; P < 0.05). Treatment with oxLDL impaired the in vitro vasculogenesis ability of EPCs. The total length of the tube structures in each photograph was decreased [25 microg/ml: (2.9 +/- 0.5) mm, 50 microg/ml: (1.8 +/- 0.5) mm versus control: (5.0 +/- 0.6) mm; P < 0.05]. The tube structure was severely disrupted, resulting in an incomplete and sparse tube network. However, all the detrimental effects on EPC were attenuated by pretreatment of EPC with LOX-1 mAb. In addition, Western blot analysis revealed that oxLDL increased LOX-1 protein expression from 100% to (172 +/- 8)% at a dose of 50 microg/ml. Furthermore, oxLDL caused an increase in LOX-1 mRNA expression from 100% to (174 +/- 39)% at a dose of 50 microig/ml.
CONCLUSION
OxLDL can directly inhibit EPC survival and activity and these effects are mediated by its receptor, LOX-1.
目的
研究氧化型低密度脂蛋白（oxLDL）是否影响内皮祖细胞（EPC）的存活及活性，以及这些作用是否由凝集素样氧化型低密度脂蛋白受体（LOX-1）介导。
方法
从人脐血中分离出的CD34⁺细胞在内皮细胞生长培养基-2（EGM-2）中培养。培养14天后，部分EPC用10、25、50μg/ml的oxLDL刺激48小时；部分先用LOX-1单克隆抗体（LOX-1的阻断抗体）预孵育24小时，然后暴露于50μg/ml oxLDL中48小时；其他未作进一步处理的用作对照。检测EPC的存活情况以及黏附、迁移和形成管腔的能力。同时检测LOX-1蛋白和mRNA表达水平。
结果
用25μg/ml及更高浓度的oxLDL孵育导致EPC凋亡呈剂量依赖性增加[25μg/ml：（15.8±1.1）%，50μg/ml：（18.8±2.0）%，而对照为：（9.0±1.2）%；P<0.05]。用oxLDL处理导致迁移率显著降低[25μg/ml：（5.7±1.0）%，50μg/ml：（5.1±0.8）%，而对照为：（9.5±0.8）%；P<0.05]。用oxLDL处理的EPC对纤连蛋白的黏附呈剂量依赖性降低（25μg/ml：33±2，50μg/ml：30±3，而对照为：37±5；P<0.05）。用oxLDL处理损害了EPC的体外血管生成能力。每张照片中管腔结构的总长度缩短[25μg/ml：（2.9±0.5）mm，50μg/ml：（1.8±0.5）mm，而对照为：（5.0±0.6）mm；P<0.05]。管腔结构严重破坏，导致管腔网络不完整且稀疏。然而，如果先用LOX-1单克隆抗体预处理EPC，则oxLDL对EPC的所有有害作用均减弱。此外，蛋白质印迹分析显示，在50μg/ml剂量时，oxLDL使LOX-1蛋白表达从100%增加至（172±8）%。此外，在50μg/ml剂量时，oxLDL使LOX-1 mRNA表达从100%增加至（174±39）%。
结论
oxLDL可直接抑制EPC的存活及活性，且这些作用由其受体LOX-1介导。
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