LIVER/INTESTINAL METABOLISM OF BILE ACIDS/CHOLESTEROL

描述（由申请人提供）： 背景资料：胆固醇和胆汁酸在“西方社会”的几种主要疾病中起着重要作用，包括：动脉硬化、胆固醇结石病、胆汁淤积性肝病和结肠癌。本次更新申请的总体目标旨在更详细地了解身体如何调节胆汁酸和胆固醇稳态，肝脏/肠道生理学，并确定二级胆汁酸是否参与胆固醇结石疾病的风险。总体目标将通过以下具体目标来实现：a）确定哪些细胞信号传导途径在原代肝细胞中被胆汁酸激活，以及哪些在调节涉及胆固醇代谢和磷脂转运的基因中是重要的; B）确定JNK-1和JNK 2缺失小鼠在胆固醇稳态机制中是否有缺陷，以及胆汁酸激活的细胞信号传导途径是否“串扰”与胆汁酸激活的核受体例如，FXR（Dent，Hylemon）; c） 详细表征固醇12 α-羟化酶（CYP 8b 1）启动子中的FTF/HNF-4位点，并阐明FTF/SHP特异性调节CYP 8b 1转录的分子机制; d）表征参与SREBP-2介导的CYP 8B 1启动子抑制的分子机制; e）表征SREB-2介导的CYP 8b 1（Gil）抑制的意义和生理作用; f）确定类固醇生成急性调节（星星）蛋白和其他细胞内胆固醇转运蛋白的作用，（SCP-2，MLN 64）在调节肝脏中胆汁酸合成中的作用; g）确定星星是否在肝脏中表达（潘达克，Gil）; h）确定来自梭菌的胆汁酸7 α和7 β-脱氢酶的三维（3D）结构和催化机制; i）表达、纯化和表征来自C.齿; j）克隆、测序和分析来自Clostridium hylemonae TN 271的bai操纵子; k）从具有高（>30%）脱氧胆酸的胆固醇结石患者和对照中分离、表征和鉴定胆酸7 α-脱羟基化细菌;以及I）确定结石患者是否被独特种类的7 α-脱羟基化细菌定殖。（Hylemon，Heuman）.

DESCRIPTION (provided by applicant): Background: Cholesterol and bile acids have been implicated in playing important roles in several major diseases of "Western Society" including: arteriosclerosis, cholesterol gallstone disease, cholestatic liver diseases, and colon cancer. The overall goal of this renewal application is aimed at a more detailed understanding of how the body regulates bile acid and cholesterol homeostasis, liver/intestinal physiology and determining if secondary bile acids are involved in the risk of cholesterol gallstone disease. The overall goal will be accomplished through the following specific aims: a) determine which cell signaling pathways are activated by bile acids in primary hepatocytes and which are important in regulating genes involved in cholesterol metabolism and phospholipid transport; b) determine if JNK-1 and JNK2 null mice are defective in cholesterol homeostatic mechanisms and if bile acid activated cell signaling pathways "cross-talk" with bile acid activated nuclear receptors e.g., FXR (Dent, Hylemon); c) characterize in detail the FTF/HNF-4 site in the sterol 12alpha-hydroxylase (CYP8bl) promoter and elucidate the molecular mechanism by which FTF/SHP specifically regulates CYP8b1 transcription; d) characterize the molecular mechanism involved in the SREBP-2 mediated suppression of the CYP8B1 promoter; e) characterize the significance and physiological role SREB-2-mediated suppression of CYP8b1 (Gil); f) determine the role of steroidogenic acute regulatory (StAR) protein and other intracellular cholesterol transport proteins (SCP-2, MLN64) play in the regulation of bile acid synthesis in the liver; g) determine if StAR is expressed in the liver (Pandak,Gil); h) determine the 3 dimensional (3D) structure and catalytic mechanism of bile acid 7alpha and 7beta-dehydratase from Clostridium scindens; i) express, purify, and characterize a novel 3-oxo-delta4steroid oxidoreductase from C. scindens; j) clone, sequence, and analyze the bai operon from Clostridium hylemonae TN271; k) isolate, characterize, and identify cholic acid 7alpha-dehydroxylating bacteria from cholesterol gallstone patients with high (>30%) deoxycholic acid and controls; and I) determine if gallstone patients are colonized by unique species of 7alpha-dehydroxylating bacteria. (Hylemon, Heuman).