Development of new drug for intractable hyperlipidemia and its clinical application

我们发现低密度脂蛋白（LDL）的加入可引起细胞内胆固醇酯含量的变化，从而调节载脂蛋白B-100（apo B）的分泌。LDL可抑制apo B蛋白自身的降解，使apo B分泌量呈剂量依赖性增加。载脂蛋白B蛋白从载脂蛋白B的mRNA翻译后，微粒体甘油三酯转移蛋白（MTP）立即与载脂蛋白B蛋白组装。结果，形成VLDL颗粒。因此，MTP在调节VLDL的产生和分泌中起重要作用。为了研究这种调控机制，我们首先克隆了MTP的全长cDNA，成功地将MTP cDNA转染CHO细胞，并检测了MTP蛋白。本研究主要进行了以下几个方面的工作：1）建立MTP在兔肝细胞中的过表达系统; 2）利用转铁蛋白启动子建立MTP过表达的转基因小鼠; 3）分析MTP、HDP-70和未知蛋白等对apo-B蛋白翻译后修饰的调控作用。

We found apolipoprotein B-100 (apo B) secretion is regulated in response to the change of intracellular cholesteryl ester contents by adding low density lipoprotein (LDL). LDL caused a significant dose-dependent increase in apo B secretion, because of preventing the degradation of apo-B protein itself. Immediately after apo B protein is translated from mRNA of apo B,microsomal triglyceride transfer protein (MTP) makes assembly with apo B protein. As a result, VLDL particles are formed. Therefore MTP plays an important role for regulating VLDL production and secretion. To investigate this regulation, we first cloned full length of cDNA for MTP,succeeded to transfect MTP cDNA to CHO cells and detected MTP protein. We are now doing following experiments.1) To establish MTP overexpression system in rabbit hepatocytes.2) To establish transgenic mouse which over express MTP cDNA using transferin promoter.3) To analyze proteins which could regulate post-translational modification of apo-B protein, suchi as MTP,HDP-70 and unknown protein.