Plasma Apolipoprotein Mutants and their Implication on Lipoprotein Metabolism

血浆载脂蛋白突变体及其对脂蛋白代谢的影响

• 批准号: 02671116
• 负责人: YAMAMURA Taku
• 金额: $ 1.47万
• 依托单位: National Cardiovascular Center Research Institute
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02671116/
• 关键词: Apolipoprotein E; Atherosclerosis; Lipoprotein; LDL receptor; Mutant

Serum lipoproteins and apo E were analyzed from 199 patients in CCU, having angina pectoris or myocardial infarction, and from 211 healthy subjects. The frequency of apo E4 was higher and that of E2 was lower in the CCU group than in the control group. Apo E mutants, E7 and E5, were also frequent in the CCU group. When we examined serum lipoproteins by the apo E phenotypes, the subjects with an E3/2 phenotype had reduced LDL and increased very low density lipoprotein (VLDL) concentrations, and those with an E4/3 phenotype had increased LDL levels in serum. The results suggested that the E4 and E2 isoproteins were positive and negative risk factors for atherosclerosis, respectively. One of the mechanisms of atherosclerosis is associated with the action of apo E isoproteins on serum LDL levels.We have previously demonstrated unique isoproteins of apo E (apo E5 and E7) associated with liyperlipidemia and atlierosclerosis. Gene analysis of E5 showed that a G to A substitution had resulted … More in a Glu to Lys substitution at the third position of the mature protein. F, 7 had two G to A substitutions, resulting in -Glu-Glu- to -Lys-Lys- substitution at positions 244 and 245. We characterized the activity of apo E5 and apo E7 binding to LDL receptors on human fibroblasts. The affinity of apo E5 was twice that of wild form of apo E3. Apo E7, however, had a lower receptor affinity than apo E3. The high affinity, of apo E5 may result in a high uptake of apo E5-containing lipoproteins by the liver and lead to a down-regulation of LDL receptors in the liver. We can postulate that the subjects with apo E5 are susceptible to hypercholesterolemia and in consequence to atherosclerosis.We developed a rapid, accurate, and sensitive method for determining apo E molecular species, and to utilize this method we investigated the relationship between apo E isoproteins and serum lipoprotein metabolism in children. Apo E phenotypes and serum lipoprotein levels were determined in 767 school children aged 7, 10 and 13 years old. Apo E phenotyping was performed by immunoblotting of an isoelectric focusing gel. Serum samples were treated with neuraminidase before delipidation. Serum cholesterol and LDL-cholesterol concentrations increase'd in the order of E3/2 -> 1/2 E3/3 -> E4/3 in each agegroup. The effect of the apo E polymorphism in serum apo B was the same tendency as cholesterol levels, but the opposite effect on serum apo E concentrations was observed. It was noteworthy that the effect of apo E isoforms on serum lipoproteins had been revealed even in childhood. We suggest the possibility that hyperlipoproteinemia and atherosclerosis miglit be prevent by dietary control based on apo E phenotypes early in life. Less

本文分析了199例冠心病心绞痛或心肌梗塞患者及211例健康人的血清脂蛋白和载脂蛋白E。CCU组载脂蛋白E_4频率高于对照组，E_2频率低于对照组。载脂蛋白E突变体E7和E5在CCU组中也很常见。当我们通过载脂蛋白E表型检测血清脂蛋白时，E3/2表型受试者的LDL水平降低，极低密度脂蛋白（VLDL）浓度升高，而E4/3表型受试者的LDL水平升高。结果提示，E_4和E_2同工酶分别是动脉粥样硬化的阳性和阴性危险因素。动脉粥样硬化的机制之一与载脂蛋白E同工蛋白对血清低密度脂蛋白水平的作用有关。我们之前已经证明了载脂蛋白E的独特同工蛋白（载脂蛋白E5和E7）与高脂血症和动脉粥样硬化有关。E5的基因分析表明，一个G到A的取代导致了 ...更多信息 在成熟蛋白质的第三位置处的Glu至Lys取代中。F，7有两个G到A的取代，导致在位置244和245处的-Glu-Glu-到-Lys-Lys-的取代。我们表征了载脂蛋白E5和载脂蛋白E7与人成纤维细胞上LDL受体结合的活性。载脂蛋白E5的亲和力是野生型载脂蛋白E3的两倍。然而，载脂蛋白E7的受体亲和力低于载脂蛋白E3。载脂蛋白E5的高亲和力可能导致肝脏对含载脂蛋白E5的脂蛋白的高摄取，并导致肝脏中LDL受体的下调。我们建立了一种快速、准确、灵敏的载脂蛋白E（apoE）分子种类测定方法，并利用该方法研究了儿童apoE同功蛋白与血清脂蛋白代谢的关系。本文对767名7、10、13岁学龄儿童的载脂蛋白E表型和血清脂蛋白水平进行了测定。通过等电聚焦凝胶免疫印迹法进行载脂蛋白E表型分析。血清样品在脱脂前用神经氨酸酶处理。血清胆固醇和低密度脂蛋白胆固醇浓度在各年龄组均按E3/2 -> 1/2 E3/3 -> E4/3的顺序升高。载脂蛋白E基因多态性对血清载脂蛋白B水平的影响与胆固醇水平的影响趋势一致，而对血清载脂蛋白E浓度的影响则相反。值得注意的是，载脂蛋白E异构体对血清脂蛋白的影响甚至在儿童时期就已被揭示。我们认为，高脂蛋白血症和动脉粥样硬化可以通过在生命早期基于载脂蛋白E表型的饮食控制来预防。少

项目成果

山村 卓: "アポEイソ蛋白のLDLーレセプタ-への結合能について" 動脈硬化. 18. 263-268 (1990)

Takashi Yamamura：“关于 apoE 同蛋白与 LDL 受体的结合能力” 动脉硬化 18. 263-268 (1990)

山村 卓: "高脂血症「アポ蛋白とその役割り」" 南江堂, 264(170-176) (1991)

山村隆：“高脂血症“脱辅基蛋白及其作用”Nankodo，264（170-176）（1991）

Nomura. S., Yamamura, T., Yamamoto, A., Haze, Hiramori, K., Hara, H., Yamaguchi, T., and Pokrovsky, S. N.: "The association between lipoprotein(a) and severity of coronary and cerebral atherosclerosis, especially in normocholesterolemic subjects." Atheros

野村。

Akira Yamamoto: "Risk factors for atherosclerotic vascular diseases with special reference to the relationship between apolipoprotein E mutants and hyperlipidemia" Ann.N.Y.Acad.Sci.598. 58-65 (1990)

Akira Yamamoto：“动脉粥样硬化性血管疾病的危险因素，特别是载脂蛋白 E 突变体与高脂血症之间的关系”Ann.N.Y.Acad.Sci.598。

Li-Ming Dong: "Site-directed mutagenesis of an apoE mutant,apoE5(Glu_3→Lys):the binding activity of the expressed apoE5 to LDL receptor" Biochem.Biophys.Res.Commun.(1991)

Li-Ming Dong：“apoE突变体的定点诱变，apoE5（Glu_3→Lys）：表达的apoE5与LDL受体的结合活性”Biochem.Biophys.Res.Commun.（1991）