Differential Effect of apoE isoform on cholesterol-loaded macrophage

apoE 亚型对胆固醇负载巨噬细胞的不同作用

基本信息

批准号：
10671058
负责人：
TSUKAMOTO Kazuhisa
金额：
$ 2.11万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

Apolipoprotein E (apoE) plays a key role in the lipoprotein metabolism and atherosclerotic diseases. There exist three major common isoforms in human apoE, i.e., E2, E3 and E4. These isoforms have been known to have differential effect on lipoprotein metabolism and atherosclerosis. In the present study, in order to investigate the roles of these isoforms on 1) the reverse cholesterol transport from the macrophages and 2) VLDL-triglycerides lipolysis, we utilized adenoviral vector for the expression of these isoforms.The RAW264.7 mouse macrophage cell line, which does not express apoE endogenously, was cholesterol-loaded. After loading cholesterol, the cells were infected with adenoviral vectors to express apoE isoforms. The expression of apoE2 reduced cellular esterified-cholesterol levels significantly compared with control cells infected with LacZ adenovirus. ApoE3 and E4 also reduced the cellular cholesterol content, however, their effect was not so much effective as apoE2. In the n … More ext experiment, cholesterol-loaded RAW264.7 cells were incubated with the medium harvested from the HeLa cells previously infected with apoE adenovirus, in order to elucidate the role of exogenous apoE on reverse cholesterol transport. This experiment revealed that apoE3 is effective in the reverse cholesterol transport, however, apoE2 and E4 have little effect. Finally, to elucidate the role of apoE on VLDL-triglycerides lipolysis, adenoviral vectors were injected to apoE/LDL-receptor double deficient mice and apoE-containing VLDL was obtained. These VLDL particles were subjected to in vitro lipolysis assay with bovine lipoprotein lipase, with changing the ratio of apoE/TG. This experiment revealed that the existence of apoE on VLDL particles inhibits lipolysis regardless of its isoform, and increasing ratio of apoE2/TG had more inhibitory effect on the lipolysis compared with E3 and E4.In summary, apoE isoforms have differential effect on reverse cholesterol transport from macrophages not only when they were expressed endogenously but also when they were added exogenously. The VLDL-lipolysis is inhibited by apoE regardless of its isoform, and apoE2 has more substantial inhibitory effect compared with the other two isoforms. Less

载脂蛋白E（APOE）在脂蛋白代谢和动脉粥样硬化疾病中起关键作用。人apoe中存在三个主要的共同亚型，即E2，E3和E4。已知这些同工型对脂蛋白代谢和动脉粥样硬化具有差异作用。 In the present study, in order to investigate the roles of these isoforms on 1) the reverse cholesterol transport from the macrophages and 2) VLDL-triglycerides lipolysis, we utilized adenoviral vector for the expression of these isoforms.The RAW264.7 mouse macrophage cell line, which does not express apoE endogenously, was cholesterol-loaded.加载胆固醇后，用腺病毒载体感染细胞以表达APOE同工型。与感染LACZ腺病毒的对照细胞相比，APOE2的表达降低了细胞酯化胆固醇水平。 APOE3和E4还降低了细胞胆固醇含量，但是它们的作用并不像APOE2那样有效。在N…更多的Ext实验中，将胆固醇载的RAW264.7细胞与先前感染APOE腺病毒的HeLa细胞收获的培养基一起孵育，以阐明外源APOE在反向胆固醇转运中的作用。该实验表明，APOE3在反向胆固醇转运方面有效，但是，APOE2和E4的作用很小。最后，为了阐明APOE在VLDL-甘油三酸酯脂解中的作用，将腺病毒载体注射到APOE/LDL受体双受体双缺陷小鼠中，并获得了含APOE的VLDL。将这些VLDL颗粒用牛脂蛋白脂肪酶进行体外脂肪分解测定，并改变APOE/TG的比例。该实验表明，在VLDL颗粒上的APOE存在抑制脂肪分解不管其同工型如何，并且与E3和E4.的apoE2/Tg的增加对脂肪分解具有更大的抑制作用，与E3和E4. IN摘要相比，ApoE同工型在杂酚醇从杂物中的反向转运时具有相差的效果，而在杂噬细胞中也不得不exepersepersepersepersepersepersepers exenoge。与其他两个同工型相比，APOE抑制VLDL-脂解会被APOE抑制，并且APOE2具有更大的抑制作用。较少的