Molecular Basis of Intracellular Cholesterol Homeostasis

在本研究期间，载脂蛋白-细胞相互作用组装HDL的机制和生理相关性的研究成果总结如下。在小鼠体内再现了HDL降低药物普罗布考对HDL组装反应的抑制，并证明该反应是血浆HDL的主要来源（BBA 1485：199，2000），并且该反应的主要器官是肝脏（ATVB 21，394，2001）。小鼠单核细胞白血病细胞RAW 264中HDL的组装由cAMP诱导，与载脂蛋白与细胞的物理结合平行，并且abca 1 mRNA增加10托姆（Biochemistry 39，11092，2000）。从THP-1细胞和成纤维细胞的实验中发现，ABCA 1不是HDL组装的绝对必需品，小窝蛋白-1在胆固醇掺入HDL中起重要作用，孕酮通过未知的机制抑制该途径（JLR 41，1952，2000 ; JBC 277，7929，2002 ; BBA 1532，173，2001）。膜筏被认为是HDL组装的场所（JLR 41，894，2000）。当ABCA 1被转染并在HEK 293中功能性表达时，显示该蛋白质具有切割的信号肽和暴露于外部的N-末端（BBRC 283，1019，2001）。上述结果的一部分总结在一篇综述文章（BBA 1529，231，2000）中。

During the current grant term, research accomplishment is summarized below for the mechanism and physiological relevance of HDL assembly by apolipoprotein-cell interaction. Inhibition of the HDL assembly reaction by an HDL-lowering drug probucol was reproduced in mice in vivo, and demonstrated the this reaction is a main source of plasma HDL (BBA 1485 : 199, 2000) and the main organ for the reaction is the liver (ATVB 21, 394, 2001). Assembly of HDL in mouse monocytic leukemia cell RAW 264 is induced by cAMP in parallel with physical binding of apolipoprotein to the cell, and with 10-tome increase of abca1 mRNA (Biochemistry 39, 11092, 2000). From the experiments with THP-1 cells and fibroblasts, it was revealed that ABCA1 is not absolute requirement for the HDL assembly, that caveolin-1 plays an important role in incorporation of cholesterol into the HDL, and that progesterone inhibits this pathway by an unknown mechanism (JLR 41, 1952, 2000 ; JBC277, 7929, 2002 ; BBA 1532, 173, 2001). Membrane raft was suggested to be a site for the HDL assembly (JLR41, 894, 2000). When ABCA1 is transfected and functionally expressed in HEK293, the protein was shown with a signal peptide cleaved and the N-terminal exposed to outside (BBRC 283, 1019, 2001). A part of the results above is summarized in a review article (BBA 1529, 231, 2000).