氧化低密度脂蛋白对巨噬细胞Toll样受体-4的表达效应

The Expression of the Effect of Oxidized LDL on Toll-like Receptor-4 in Cultured Human Monocyte-driven Macrophages

目的研究低密度脂蛋白(LDL)氧化对人单核细胞源巨噬细胞Toll样受体-4(TLR-4)表达的影响及其机制。方法用RPM I 1640培养基体外培养人THP-1单核细胞系,加入佛波醇肉豆蔻酸乙酸酯(PMA)培养48 h使其分化为巨噬细胞,加入氧化低密度脂蛋白(Ox-LDL)或LDL,用免疫细胞化学、蛋白质免疫印迹和反转录聚合酶链反应(RT-PCR)方法,观察脂蛋白氧化前、后对巨噬细胞表达TLR-4蛋白及TLR-4 mRNA的影响。结果Ox-LDL可提高TLR-4蛋白及TLR-4 mRNA的表达(P<0.01);而LDL对TLR-4蛋白及其mRNA的表达无影响(P<0.05)。结论LDL的氧化可能促进THP-1源巨噬细胞TLR-4转录水平的上调,导致蛋白质的合成增加;Ox-LDL可能是动脉粥样硬化中炎症的始发原因之一。

Objective To explore the effect of oxidized LDL on the expression of Toll - like receptor -4 （ TLR -4 ） in human monocyte - driven macrophage and its mechanism, Methods The THP - 1 human monocytic leukemia cell line （ THP - 1 ） was chosen in our study and cultured in RPMI 1640. The differentiation of THP - 1 cells into maerophages （MP） was induced by using myristate acetate （PMA） for 48 hours. Then the maerophage cells were incubated with oxidized LDL （Ox - LDL） or LDL. The protein mass and the mRNA level of TLR - 4 were determined in all three groups respectively. The protein and mRNA level were detected by immunocytochemistry, Western blotting and reverse transcription polymerase chain reaction （RT - PCR）. Results The TLR -4 protein mass and mRNA level were significantly increased by Ox - LDL （ P 〈 0. 01 ）. In contrast, LDL affects the expression of neither TLR - 4 protein nor TLR - 4 mRNA significantly （ P 〈 0. 05 ）, Conclusion The upregulation of TLR - 4 gene expression in human monocyte - driven macrophages by Ox - LDL could increase TLR - 4 protein syntt, esis dramatically, Ox - LDL may be one of triggers for inflammation in atherosclerosis.