氧化型低密度脂蛋白对单核巨噬细胞株U937表达Siglec-1蛋白及分泌细胞因子的影响

Influence of oxidized low-density lipoprotein on siglec-1 expression and cytokine secretion by U937 cells

目的探讨氧化型低密度脂蛋白(ox-LDL)的致动脉粥样硬化(AS)作用是否通过上调单核巨噬细胞表面Siglec-1的表达发挥作用。方法制备ox-LDL并用不同浓度刺激人巨噬细胞株U937,48h后收集细胞和培养上清液,分别用流式细胞仪和RT-PCR检测不同浓度ox-LDL刺激后Siglec-1蛋白和Siglec-1mRNA的表达水平,并用ELISA试剂盒测定培养上清液中MIP-1α、MCP-1和IL-8的浓度。结果与对照组相比,ox-LDL能刺激U937细胞表面Siglec-1蛋白和Siglec-1mRNA表达升高(P<0.01),培养上清液中MIP-1α、MCP-1和IL-8的表达升高(P<0.01),并呈浓度依赖性。结论ox-LDL的致AS作用可能部分是通过上调单核巨噬细胞表面Siglec-1蛋白表达而活化巨噬细胞,分泌细胞因子和趋化因子诱导更多巨噬细胞和淋巴细胞的活化参与粥样斑块中的炎症反应。

Objective：To explore the role of sialic acid-binding immunoglobulin-like lectin-one （ Siglec-1） in oxidized low-density lipoprotein （ ox-LDL）-induced atherosclerotic inflammation. Methods：Ox-LDL was prepared by oxidization of native LDL; different concentrations of ox-LDL were used to treat U937 cells for 48 h. Cells and supernatants were collected. The expression of Siglec-1 protein and mRNA was examined by flow cytometry （ FCM） and real-time quantitative RT-PCR,respectively. The levels of MIP-1α,MCP-1 and IL -8 in the supernatants were determined by ELISA. Results：Stimulation with ox-LDL significantly increased Siglec-1 protein and mRNA in U937 cells compared with the control group（ P 〈 0. 01）. Meanwhile,the levels of MIP-1α,MCP-1 and IL-8 in the supernatants were also significantly increased in a concentration-dependent manner compared with those in the control group（ P 〈 0. 01）. Conclusion：The proatherogenic effect of ox-LDL may be partly through up-regulating Siglec-1 expression in macrophages and enhancing the expression of inflammatory cytokines and chemokines. The activated macrophages recruit more macrophages and lymphocytes to the site of atherosclerotic plaques and exacerbate the inflammatory responses.