Nucleolin protects macrophages from oxLDL-induced foam cell formation through up-regulating ABCA1 expression
Nucleolin protects macrophages from oxLDL-induced foam cell formation through up-regulating ABCA1 expression
复制标题
核仁素通过上调 ABCA1 表达保护巨噬细胞免受 oxLDL 诱导的泡沫细胞形成
DOI：
10.1016/j.bbrc.2017.03.047
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发表时间：
2017-04-29
影响因子：
3.1
通讯作者：
Xiao, Xianzhong
中科院分区：
文献类型：
--
作者：
Li, Yuanbin;Jiang, Bimei;Xiao, Xianzhong
近年来的研究表明，核仁素作为一种多功能的RNA结合蛋白，在氧化应激条件下对心肌细胞和内皮细胞具有保护作用。然而，核仁素在巨噬细胞源性泡沫细胞形成中的功能及其潜在机制在很大程度上尚未被探索。ApoE-/-小鼠用高脂饮食（HFD）喂养10-24周。通过蛋白质印迹法或免疫荧光法测量蛋白质表达，并通过qRT-PCR检测mRNA水平的基因表达。采用油红0染色法、高效液相色谱法和NBD-胆固醇法检测巨噬细胞脂质含量。用放线菌素D（ActD）测定巨噬细胞中ABCA 1 mRNA的稳定性。使用免疫共沉淀（co-IP）评估核仁素与ABCA 1 mRNA的相互作用。与ApoE-/-小鼠的早期斑块相比，晚期斑块中核仁素蛋白水平显著降低，其中巨噬细胞泡沫细胞占据主体。氧化型低密度脂蛋白（oxLDL）可显著降低RAW264.7巨噬细胞核仁素mRNA和蛋白水平的表达，并呈剂量和时间依赖性。此外，核仁素过表达显着衰减脂质积累oxLDL挑战巨噬细胞通过增加胆固醇流出。此外，核仁素过表达显著增加ATP结合盒转运体A1（ABCA 1）在mRNA和蛋白水平的表达，而不影响清道夫受体（SR）-A、SR-B1、CD 36和ATP结合盒转运体G1（ABCG 1）在mRNA水平的表达。此外，核仁素过表达增加了ABCA 1 mRNA在巨噬细胞中的稳定性，而核仁素消融废除了oxLDL诱导的ABCA 1上调。核仁素上调ABCA 1的表达是由于其与RNA的相互作用。我们的数据表明，核仁素抑制泡沫细胞的形成，通过增强ABCA 1 mRNA的稳定性，随后增加胆固醇流出。(C)2017爱思唯尔公司All rights reserved.
Our recent studies have indicated that nucleolin, as a multifunctional RNA-binding protein, exerts protective effects in the myocardial cells and endothelial cells under the condition of oxidative stress. However, the function of nucleolin and its potential mechanism in macrophage-derived foam cell formation remain largely unexplored. ApoE-/- mice were fed with a high-fat diet (HFD) for 10-24 weeks. Protein expression was measured by western blotting or immunofluorescence, and gene expression at the mRNA level was detected by qRT-PCR. The level of lipid in macrophages was examined by Oil Red 0 staining, high-performance liquid chromatography (HPLC) and NBD-cholesterol. Actinomycin D (Act D) was used to determine the stability of ABCA1 mRNA in macrophages. The interaction of nucleolin with ABCA1 mRNA was assessed using co-immunoprecipitation (co-IP). The aortas advanced plaques demonstrated significantly lower levels of nucleolin protein compared with early plaques in ApoE-/- mice, in which the macrophage foam cells occupied main body. Nucleolin expression at the mRNA and protein levels in RAW264.7 macrophages was significantly reduced by oxidized low-density lipoprotein (oxLDL) in a dose- and time-dependent manner. Furthermore, nucleolin overexpression markedly attenuated lipid accumulation in oxLDL-challenged macrophages through increasing cholesterol efflux. In addition, nucleolin overexpression significantly increased the expression of ATP-binding cassette transporter A1 (ABCA1) at the mRNA and protein levels without affecting expressions of scavenger receptors (SR)-A, SR-B1, CD36 and ATP-binding cassette transporter G1 (ABCG1) at the mRNA level. Moreover, nucleolin overexpression increased the stability of ABCA1 mRNA in macrophages, whereas nucleolin ablation abrogated the oxLDL-induced up-regulation of ABCA1. The up-regulation of ABCA1 by nucleolin resulted from its protein-RNA interaction. Our data suggested that nucleolin inhibited foam cell formation through enhancing stability of ABCA1 mRNA and subsequently increasing cholesterol efflux. (C) 2017 Elsevier Inc. All rights reserved.