依泽替米贝通过上调甾醇调控元件结合蛋白2、低密度脂蛋白受体促进肝细胞摄取低密度脂蛋白胆固醇  

Ezetimibe promotes hepatic uptake of low density lipoprotein cholesterol by up-regulating the expressions of sterol regulatory element binding protein-2 and low density lipoprotein receptor

作　　者：方敏 李亚梅[1] 向德标[1] 龚勇珍[1] 廖端芳[1] 张彩平 郑熙隆[1] FANG Min;LI Ya-Mei;XIANG De-Biao;GONG Yong-Zhen;LIAO Duan-Fang;ZHANG Cai-Ping;ZHENG Xi-Long(Division of Stem Cell Regulation and Application, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China;Department of Biochemistry ＆ Molecular Biology, Pharmacy ＆ Biological Science School, University of South China, Hengyang , ttunan 421001, China)

机构地区：[1]湖南中医药大学干细胞中药调控与应用实验室,湖南省长沙市410208 [2]南华大学药学与生物科学学院生物化学与分子生物学教研室,湖南省衡阳市421001

出　　处：《中国动脉硬化杂志》2018年第1期7-13,共7页Chinese Journal of Arteriosclerosis

基　　金：国家自然科学基金项目(81600291、81773736)

摘　　要：目的 探讨依泽替米贝对肝脏低密度脂蛋白胆固醇（LDLC）摄取的影响及其机制。 方法 使用5 mg/（kg·d）依泽替米贝灌胃高脂模型小鼠,4个月后测定其血液中总胆固醇（TC）、LDLC和高密度脂蛋白胆固醇（HDLC）的含量；HE染色观察肝脏组织形态。依泽替米贝（30 μmol/L）与低密度脂蛋白（25 mg/L）共同孵育肝脏HepG2细胞24 h,油红O染色观察细胞的脂滴分布情况；酶学方法检测细胞内TC、游离胆固醇（FC）和胆固醇酯（CE）的含量；采用DiI-LDL检测细胞对LDLC的摄取情况；实时荧光定量PCR和Western blot分别检测甾醇调控元件结合蛋白2（SREBP-2）和低密度脂蛋白受体（LDLR）在mRNA及蛋白水平的表达；流式细胞术检测肝细胞膜上LDLR含量。 结果 依泽替米贝降低小鼠血浆中TC和LDLC的含量,升高HDLC含量,减少肝脏脂质沉积；提升HepG2细胞摄取LDLC的能力,促进FC向CE转化；上调HepG2细胞中SREBP-2和LDLR的表达水平,并增加LDLR在细胞膜上的分布。 结论 依泽替米贝通过上调SREBP-2、LDLR促进肝细胞摄取LDLC。Aim To investigate the effect of ezetimibe on hepatic low density lipoprotein cholesterol （LDLC） uptake and its mechanism. Methods The hyperlipidemia model mice had intragastric administration of 5 mg/（kg·d） ezetimibe. After four months, the contents of total cholesterol （TC）, LDLC and high density lipoprotein cholesterol （HDLC） were measured in the blood of mice, and liver tissue morphology was observed by HE staining. HepG2 cells were incubated with ezetimibe （30 μmol/L） and low density lipoprotein （25 mg/L） for 24 hours. The distribution of lipid droplets in cells was observed by oil red O staining. Enzymatic method was used to detect the contents of intracellular TC, free cholesterol （FC） and cholesteryl ester （CE）. The uptake of LDLC in cells was detected by DiI-LDL. Real-time fluorescence quantitative PCR and Western blot were used to detect sterol regulatory element binding protein-2 （SREBP-2） and low density lipoprotein receptor （LDLR） expressions at mRNA and protein level, respectively. LDLR content in the hepatic cell membrane was detected by flow cytometry. Results Ezetimibe reduced the content of TC and LDLC in the plasma of mice, increased the content of HDLC and reduced the lipid deposition in liver. Ezetimibe enhanced the ability of HepG2 cells to take LDLC, and promoted the transformation of FC into CE. Ezetimibe up-regulated the expressions of SREBP-2 and LDLR in HepG2 cells, and increased the distribution of LDLR on the cell membrane. Conclusion Ezetimibe can promote the uptake of LDLC in liver cells by up-regulation of SREBP-2 and LDLR.

关 键 词：依泽替米贝 甾醇调控元件结合蛋白2 低密度脂蛋白受体 低密度脂蛋白胆固醇 

分 类 号：R966[医药卫生—药理学]