LIVER/INTESTINAL METABOLISM ON BILE ACIDS/CHOLESTEROL

胆固醇和胆汁酸在这一过程中 在“西方社会”的几个主要疾病中的作用，包括： 动脉硬化、胆固醇结石形成、胆汁淤积性肝 疾病和结肠癌发生。 此次更新的总体目标是 应用程序旨在更详细地了解胆汁的作用 酸在胆固醇和胆汁酸体内平衡的调节中起作用， 肝/肠生理学和胆固醇结石疾病。 的 总体目标将通过以下具体措施实现 目的：[1] a）确定蛋白激酶C的哪种亚型是 参与胆固醇7 α-羟化酶的调节; B） 确定蛋白激酶C亚型的活化机制 c）定义蛋白激酶C和胆汁酸响应性蛋白激酶C; 胆固醇7 α-羟化酶启动子的元件; d） 确定胆汁酸是否在体内激活蛋白激酶C亚型 肝脏和回肠（Vlahcevic，Stravitz，Heuman，Hylemon）; [2] a） 定量胆汁盐对模型膜的吸附; B）开发 并验证了胆盐膜的一般定量模型 c）确定卵磷脂和胆固醇对吸附的影响; 胆盐对膜的毒性; d）确定 胆汁脂质成分对动物模型胆汁胆盐毒性的影响 胆盐诱导的肝损伤; e）确定蛋白激酶C 胆汁盐的激活是胆汁积聚的结果 膜表面的盐，可以通过定量预测 胆盐-膜吸附的建模（Heuman，Stravitz， Valhcevic ; [3] a）选择性过表达胆固醇7 α- 羟化酶、甾醇27-羟化酶、胆固醇酯水解酶和 酰基辅酶A：胆固醇酰基转移酶（Hep G2和中国人 仓鼠卵巢细胞）; B）评估每种酶在 维持细胞和全身胆固醇稳态， 体内重组腺病毒载体（仓鼠）; c）研究 调节胆固醇酯水解酶和酰基辅酶A：胆固醇 原代大鼠肝细胞培养物和胆汁体内的酰基转移酶 酸、胆固醇和激素（潘达克、弗拉切维奇）; [4] a） 完成一个大胆汁酸的克隆、测序和分析 来自肠真杆菌属VPI的可诱导操纵子（bai） 12708; B）确定每个基因产物编码的功能， 该操纵子在胆汁酸7 α/β-脱羟基化中起作用; c）分离， 表征和鉴定胆汁酸7 α-脱羟基细菌 来自胆固醇结石患者，其具有高（>30%）水平的 去氧胆酸，并确定这些患者是否被 独特的7种α-脱羟基细菌（Hylemon，Berr）。

Cholesterol and bile acids have been implicated in playing important roles in several major diseases of "Western Society" including: arteriosclerosis, cholesterol gallstone formation, cholestatic liver disease and colon carcinogenesis. The overall goal of this renewal application is aimed at a more detailed understanding of the role bile acids play in the regulation of cholesterol and bile acid homeostasis, liver/intestinal physiology, and cholesterol gallstone disease. The overall goal will be accomplished through the following specific aims: [1] a) Determine which isoform(s) of protein kinase C is involved in the regulation of cholesterol 7 alpha-hydroxylase; b) Determine the mechanism of activation of protein kinase C isoforms by bile acids; c) Define protein kinase C and the bile acid responsive element of the cholesterol 7 alpha-hydroxylase promoter; d) Determine if bile acids activate protein kinase C isoforms in vivo in liver and ileum (Vlahcevic, Stravitz, Heuman, Hylemon); [2] a) Quantify adsorption of bile salts to model membranes; b) Develop and validate a general quantitative model of bile salt-membrane adsorption; c) Determine the effects of lecithin and cholesterol on toxicity of bile salts toward membranes; d) Determine the effect of biliary lipid composition on biliary bile salt toxicity in animal models of bile salt induced liver injury; e) Determine if protein kinase C activation by bile salts are consequences of the accumulation of bile salts on the membrane surface that can be predicted by quantitative modeling of bile salt-membrane adsorption (Heuman, Stravitz, Valhcevic ; [3] a) Selective overexpression of cholesterol 7 alpha- hydroxylase, sterol 27-hydroxylase, cholesterol ester hydrolase and acyl CoA:cholesterol acyltransferase in vitro (Hep G2 and Chinese hamster ovary cells); b) Assess the role each enzyme plays in maintaining cellular and whole body cholesterol homeostasis using recombinant adenovirus vectors in vivo (hamsters); c) Investigate the regulation of cholesterol ester hydrolase and acyl CoA:cholesterol acyltransferase in primary rat hepatocyte cultures and in vivo by bile acids, cholesterol and hormones (Pandak, Vlahcevic); [4] a) Complete the cloning, sequencing and analysis of a large bile acid inducible operon (bai) from the intestinal Eubacterium sp. VPI 12708; b) Determine the function that each gene product encoded by this operon plays inbile acid 7 alpha/beta-dehydroxylation; c) Isolate, characterize and identify bile acid 7 alpha-dehydroxylating bacteria from cholesterol gallstone patients having high (>30%) levels of deoxycholic acid and determine if these patients are colonized by unique 7 alpha-dehydroxylating bacterial species (Hylemon, Berr).