血管内皮细胞中ABCA1的表达及其在动脉粥样硬化发生中的意义

目的 以人的血管内皮细胞ECV304为靶点，研究Ox-LDL和8-Br-cAMP对ATP-结合盒转运子Al(ABCAl)、细胞间粘附因子-1(ICAM-1)及单核细胞趋化因子-1(MCP-1)基因mRNA和蛋白质表达的影响，阐明ABCAI基因在动脉粥样硬化(AS)形成中的可能机制。方法 复苏培养血管内皮细胞，无血清培养基培养静止12h后．分别加入Ox-LDL(30ng／m1)、8-Br-cAMP(0．5mmol／L)刺激3、6、12、24h，设未加刺激同时孵育24h的细胞为阴性对照组，以RT-PCR和Westem蛋白印迹法检测ABCA1、ICAM-1及MCP-1 mRNA和蛋白质表达量。结果 血管内皮细胞ECV304在给予Ox-LDL刺激后，ABCA1、ICAM-1、MCP-1的mRNA和蛋白质水平均增高，ICAM-1的高峰时间在12h，其余高峰时间在6h；在8-Br-cAMP的刺激下，ABCAl、ICAM-1、MCP-1的mRNA和蛋白质水平也增高。高峰时间均在6h。结论 公认的致AS因素Ox-LDL可通过引起血管内皮细胞ECV304中炎性细胞因子ICAM-1、MCP-1 mRNA及蛋白质水平增加，参与AS的形成，同时抗AS基因ABCA1在Ox-LDL刺激下代偿增加，具有AS保护作用。cAMP不仅可增加ABCA1的表达，而且可增加ICAM-1、MCP-1表达。

Expression of ABCA1 in vascular endothelial cells and its significance in the pathogenesis of atherosclerosis]

OBJECTIVE: To investigate the changes in the expressions of ATP-binding cassette transporter A1 (ABCA1), intercellular cell adhesion molecule type 1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1) at mRNA and protein levels after the treatment of the vascular endothelial ECV304 cells with oxidized low-density lipoprotein (Ox-LDL) and 8-Br-cAMP, thereby to explore possible mechanisms by which ABCA1 affects the formation of atherosclerosis (AS). METHODS: Resuscitated and cultured ECV304 cells were incubated in serum-free medium for 12 h to induce the quiescence phase of growth, which were subsequently treated with Ox-LDL (30 ng/ml) and 8-Br-cAMP (0.5 mmol/L) respectively for 3, 6, 12, and 24 h. After the cells were harvested at the specified time points, the mRNA and protein levels of ABCA1, ICAM-1 and MCP-1 were detected by RT-PCR and Western blotting, respectively. RESULTS: The mRNA and protein expression levels of ABCA1, ICAM-1 and MCP-1 all increased after treatments with Ox-LDL and 8-Br-cAMP. The highest expression of ICAM-1 occurred in cells with a 12-hour treatment, and those of ABCA1 and MCP-1 occurred following 6-hour incubation with Ox-LDL. The expression peaks of ABCA1, ICAM-1 and MCP-1 all took place after 6-hour incubation with 8-Br-cAMP. CONCLUSIONS: The mRNA and protein expressions of ICAM-1 and MCP-1 in vascular endothelial ECV304 cells increase in response to Ox-LDL treatment, in the event of which ABCA1 is also up-regulated to offer protective effects against AS. cAMP not only enhances the expression of ABCA1 but also those of ICAM-1 and MCP-1.