TLR4介导氧化型低密度脂蛋白致动脉粥样硬化作用的研究  

The effects of ox-LDL in human atherosclerosis may be mediated in part via the TLR4 pathway

作　　者：耿红莲[1] 王爱华[1] 屠小卿[1] 吴萍[1] 赵文静[1] 邓燕[1] 竺蓓[1] 仲人前[1] 

机构地区：[1]上海长征医院实验诊断科,200003

出　　处：《中华微生物学和免疫学杂志》2007年第12期1092-1095,共4页Chinese Journal of Microbiology and Immunology

摘　　要：目的探讨氧化型低密度脂蛋白(oxidized low density lipoprotein,ox-LDL)的致动脉粥样硬化作用与Toll样受体4(Toll-like receptor 4,TLR4)表达的相关性。方法构建针对TLR4的小干扰KNA(small interference RNA,siRNA)表达载体,转染人单核细胞株U937,于转染前后用不同浓度的ox-LDL刺激,用流式细胞术和实时荧光定量PCR法检测TLR4蛋白和mRNA表达变化,同时用ELISA测定NF-κB活性改变以及细胞上清液中动脉粥样硬化相关细胞因子MCP-1和IL-8的浓度变化。结果ox-LDL刺激可导致单核细胞TLR4表达上调,同时NF-κB p65活性增强,MCP-1和IL-8在细胞上清液中的浓度显著高于对照组(P<0.05),并且呈剂量依赖性;利用siRNA表达载体使TLR4表达抑制后,相同剂量的ox-LDL刺激,NF-κB p65相对活性以及MCP-1和IL-8的分泌显著低于TLR4未抑制组(P<0.05)。结论ox-LDL的致动脉粥样硬化作用至少部分是由TLR4介导的;调节TLR4的表达,可以减弱ox-LDL刺激引起的包括NF-κB活化以及MCP-1和IL-8分泌等致动脉粥样硬化效应。Objective To explore the relationship between the effects of oxidized low density lipoprotein （ox-LDL） in human atherosclerosis and the expression of Toll-like receptor 4 （TLR4）. Methods Before and after transfection with the TLR4 siRNA plasmid expression vectors, human monocytic U937 cells were stimulated with ox-LDL of the different final concentrations. The TLR4 expression was measured by flow cytometry and real time PCR; NF-κB activity and the concentrations of MCP-1 and IL-8 were detected by ELISA. Results rIhe positive rate and the mean mRNA copy number of TLR4 increased in response to ox-LDL. Simultaneously, NF-κB relative activity and the concentrations of MCP-1 and IL-8 in cell supernatant were up-regulated by ox-LDL in a dose-dependent manner（ P 〈 0.05）. TLR4 expression was inhibited by siRNA plasmid expression vectors, and NF-κB activity and the secretion of MCP-1 and IL-8 in response to ox-LDL were significantly lower in the group that TLR4 expression has been inhibited than that in the group that TLR4 expression has not been inhibited（ P 〈 0.05）. Conclsion rIhe atherogenic effects of ox-LDL could be mediated in part via the TLR4 pathway. And inhibition of TLR4 expression may down-regulate the NF-κB activity and MCP-1 and IL-8 secretion in monocytes by ox-LDL, resulting in the alleviation of the progress of atherosclerosis.

关 键 词：动脉粥样硬化 氧化型低密度脂蛋白 TOLL样受体4 小干扰RNA 

分 类 号：R543[医药卫生—心血管疾病]