TLR4激动上调内皮细胞氧化低密度脂蛋白受体LOX-1表达

TLR4 Activation Upregulates the Expression of LOX-1 in HUVEC

目的近年研究表明介导先天免疫反应的受体Toll样受体4(TLR4)参与了动脉硬化的发生发展。业已证明氧化低密度脂蛋白受体LOX1介导内皮细胞活化和功能失调,激发炎症过程,在动脉粥样硬化的发生和发展中起着极为重要作用。本研究观察TLR4激动是否调节内皮细胞LOX1表达。方法应用脂多糖(LPS)刺激体外培养的人脐静脉内皮细胞(HUVECs)24h。采用RTPCR和流式细胞术分别检测TLR4、LOX1mRNA和蛋白表达水平。为了观察转录因子NFκB在调节LOX1表达中的作用,应用NFκB特异性抑制剂咖啡酸苯乙酯(CAPE)预处理细胞,然后以LPS刺激,检测LOX1mRNA和蛋白变化。结果LPS(10～1000ng/mL)上调HUVECsTLR4和LOX1mRNA表达,LPS(1000ng/mL)上调TLR4和LOX1蛋白表达,CAPE(20μg/mL)可抑制LPS介导的LOX1表达上调。结论TLR4/NFκB信号途径可能通过上调内皮细胞LOX1表达参与动脉粥样硬化的发生及发展。

Objective Recent studies showed that Toll-like receptor 4 (TLR4), a mediator of innate immune responses, is involved in the initiation and progression of atherosclerosis. Previous studies show that endothelial dysfunction and activation mediated by lectin-like oxidized LDL receptor-1 (LOX-1) play an important role in atherosclerosis. We investigated the modulation of TLR4 activation on the expression of LOX-1 and endothelial injury in cultured endothelial cells. Methods HUVECs were incubated with LPS for 24 hours. TLR4 and LOX-1 mRNA were measured by RT-PCR. The expression percentage of TLR4 and LOX-1 positive cells was detected by flow cytometry. The role of NF-κB in modulating LOX-1 expression was examined using NF-κB inhibitor caffeic acid phenethyl ester (CAPE). Results LPS(10-1 000 ng/mL) upregulated TLR4 and LOX-1 mRNA in a dose dependent manner, while LPS(1 000 ng/mL) increased the percentage of TLR4 and LOX-1 positive cell in HUVECs. Pretreatment with CAPE inhibited LPS mediated upregulation of LOX-1 expression. Conclusion Enhanced expression of LOX-1 in endothelial cells may be one of the mechanisms by which TLR4/NF-κB involved in atherogenesis.=