Toll样受体4/核因子κB和氧化低密度脂蛋白受体LOX-1对单核内皮细胞黏附的影响

The effect of TLR4 /NF-κB activation and LOX-1 on monocyte adhesion to endothelium

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)参与动脉粥样硬化的发生发展。TLR4激动后通过诱导核因子κB(NFκB)激活,调控炎症因子的表达。研究观察TLR4/NFκB激活对人脐静脉内皮细胞(HUVECs)氧化低密度脂蛋白受体(lectinlikeoxidizedlowdensitylipoproteinreceptor1,LOX1)、细胞间黏附分子1(intercellularadhesionmolecule1,ICAM1)、E选择素(Eselectin)表达的调节,以及它们在介导单核内皮细胞黏附中的作用。方法应用脂多糖(LPS,1mg/L)刺激HUVECs24h。采用RTPCR方法检测TLR4、LOX1、ICAM1、EselectinmRNA表达水平;采用蛋白质印迹技术检测TLR4、LOX1蛋白表达水平及核蛋白NFκBp65表达的变化;采用直接计数法观察HUVECs与单核细胞的黏附率。结果LPS上调TLR4表达,激活NFκB,上调HUVECsLOX1、ICAM1、Eselectin表达,增加单核细胞与内皮细胞的黏附率;抗LOX1、ICAM1、Eselectin抗体均部分抑制LPS介导的单核与内皮细胞黏附率的增加;NFκB抑制剂咖啡酸苯乙酯(CAPE)抑制了LPS介导的上述效应。结论TLR4/NFκB激活上调LOX1、ICAM1、Eselectin表达,它们均在LPS介导的单核内皮细胞黏附过程中起部分作用,NFκB在LPS介导的上述效应中起关键调节作用,干预NFκB激活可能成为防治动脉粥样硬化的靶目标。

Objective Recent studies have shown that Toll-like receptor 4 （TLR4）, a mediator of for innate immune responses, is involved in the initiation and progression of atherosclerosis. TLR4 activation mediates the expression of chemokines and cytokines through activation of NF-κB. We investigated the expression of lectin-like oxidized low-density lipoprotein receptor-1 （LOX-1）. intercellular adhesion molecule-1 （CAM-1）, E-selectin induced by TLR4/NF-κB in human umbilical vein endothelial cells （HUVECs） , and their effects on adhesion of monocyte to HUVECs. Methods HUVECs were incubated with purified LPS for 24 h. TLR4. LOX-1. ICAM-1. E-selectin mRNA were measured by RT-PCR; the protein expression of TLR4、LOX-1 and activation of NF-κB were detected by Western blot; the adhesive percentage between HUVECs and monocytes was determined by direct counting. Results LPS （ 1 mg/L） not only enhanced expression of TLR4, activation of NF-κB and induction of LOX-1. ICAM-1. E-selectin expression, but also increased the percentage of monocyte adhesion to endothelium. Pretreatment of HUVECs with anti-LOX1, anti-ICAM-1 or anti E-selectin antibodies partly abolished the increase in monocyte adhesion to endothelium. NF-κB inhibitor CAPE suppressed LPS-induced these effects. Conclusion TLR4/ NF-κB plays an important role in monocyte-endothelium adhesion partly through upregulation of LOX-1, ICAM-1 and E-selection expression, which may provide a target for the treatment of atherosclerosis.