Regulation of Hepatic P450s by Anti-Cholesterol Drugs

抗胆固醇药物对肝脏 P450 的调节

基本信息

批准号：
7150007
负责人：
Thomas A Kocarek
金额：
$ 28.64万
依托单位：
WAYNE STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1993
资助国家：
美国
起止时间：
1993-08-01 至 2008-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7150007
关键词：
Acids Adenoviruses Anticholesteremic Agents Bile Acids Binding Biological Biological Assay CYP2B6 gene CYP3A4 gene Cells Chemicals Cholesterol Class Coenzyme A Culture Media Cytochrome P450 Data Enzymes Fluorescence Polarization Gene Transfer Heme Hepatic Hepatocyte Human In Vitro Injection of therapeutic agent Laboratories Ligands Liver Luciferases Mediating Mediator of activation protein Messenger RNA Metabolic Metabolism Methodology Modeling Mus Northern Blotting Nuclear Orphan Receptor Nuclear Receptors Orphan Oxidoreductase PPAR alpha Pathway interactions Pharmaceutical Preparations Pharmacology Phase Physiology Plasmids Pregnenolone Pregnenolone Carbonitrile Proteins RNA Interference Rattus Receptor Activation Recombinants Regulation Reporter Reporting Ro 48-8071 Site Small Interfering RNA Squalene Squalene Synthetase Squalene monooxygenase Sterols Supplementation System Testing Xenobiotics atorvastatin base cholesterol biosynthesis constitutive androstane receptor cytochrome P450 3A design farnesyl pyrophosphate fluvastatin human CYP2B6 protein in vivo inhibitor/antagonist insight isoprenoid knock-down member mevalonate nuclear receptor subfamily 1, group I, member 3, human pregnane X receptor programs receptor receptor binding response squalene cyclase squalestatin 1

项目摘要

DESCRIPTION (provided by applicant): Endogenous metabolites of the mevalonate/chotesterol/bile acid biosynthetic pathway function as intracrine regulators of hepatocyte physiology, which act by modifying the activities of orphan nuclear receptors. An anti-cholesterol drug that inhibits a key step in this pathway will cause the accumulation of one of these bioactive molecules and activate the pleiotropic responses associated with the mediating nuclear receptors, which include induction of cytochromes P450. Our hypothesis is that (1) of the anti-cholesterol drugs that induce hepatic P450s, only a subset (e.g., certain statins and the squalene monooxygenase inhibitor, NB-598) are able to bind directly to a xenobiotic-sensing nuclear receptor, and these do so in a species-specific manner; (2) squalestatin 1 induces rat CYP2B (and activates CAR) indirectly, either by causing the accumulation of a farnesoid, which functions as a CAR ligand, or by provoking a disturbance in heme metabolism; the bioactive mediator of this effect is metabolized or eliminated from the hepatocyte by a pregnenolone 16(-carbonitrile (PCN)-inducible enzyme or transporter; and (3) multiple classes of endogenous metabolites of the mevalonate/sterol/bile acid pathway that accumulate in the human hepatocyte following anti-cholesterol drug treatment and/or mevalonate supplementation are capable of inducing CYP3A and CYP2B6 expression as a consequence of PXR binding and activation. The specific aims are (1) To define the abilities of anti-cholesterol drugs to interact directly with the rat, mouse, and human CAR, PXR, and PPARalpha receptors. (2) To identify the specific branch of the mevalonate pathway that mediates squalestatin 1-inducible CYP2B expression in primary cultured rat hepatocytes. (3) To identify the mechanism that is responsible for PCN-mediated, mevalonate-reversible, suppression of squalestatin 1-inducible CYP2B expression in primary cultured rat hepatocytes, and to confirm that the mechanisms governing squalestatin 1-mediated CYP2B induction that have been defined in primary cultured rat hepatocytes are also operative in vivo. (4) To identify the specific metabolic intermediates of the mevalonate/sterol/bile acid biosynthetic pathway that regulate CYP3A and CYP2B6 expression in human hepatocyte models. These studies will provide essential new information about the pharmacology of a widely-used class of drugs, and important insights into the mechanisms underlying inducible P450 expression.

描述（由申请人提供）：甲羟戊酸/胆固醇/胆汁酸生物合成途径的内源代谢物作为肝细胞生理学的内分泌调节剂，其通过改变孤儿核受体的活性来发挥作用。抑制该途径关键步骤的抗胆固醇药物将导致这些生物活性分子之一的积累，并激活与介导核受体相关的多效性反应，其中包括细胞色素 P450 的诱导。我们的假设是 (1) 在诱导肝 P450 的抗胆固醇药物中，只有一小部分（例如某些他汀类药物和角鲨烯单加氧酶抑制剂 NB-598）能够直接与异生物质感应核受体结合，并且这些以特定物种的方式进行； (2) squalestatin 1 间接诱导大鼠 CYP2B（并激活 CAR），要么通过引起作为 CAR 配体的法尼醇积累，要么通过引起血红素代谢紊乱；这种作用的生物活性介质通过孕烯醇酮 16(-PCN) 诱导酶或转运蛋白从肝细胞中代谢或消除；(3) 甲羟戊酸/甾醇/胆汁酸途径的多类内源代谢物在抗胆固醇药物治疗和/或补充甲羟戊酸后的人肝细胞能够诱导 CYP3A 和 CYP2B6具体目标是 (1) 确定抗胆固醇药物与大鼠、小鼠和人类 CAR、PXR 和 PPARα 受体直接相互作用的能力。甲羟戊酸途径的特定分支，介导原代培养的大鼠肝细胞中角鲨他汀 1 诱导的 CYP2B 表达 (3) 确定 PCN 介导的机制。甲羟戊酸可逆地抑制原代培养的大鼠肝细胞中角鲨烯1诱导的CYP2B表达，并证实在原代培养的大鼠肝细胞中确定的控制角鲨烯1介导的CYP2B诱导的机制在体内也有效。 (4) 鉴定甲羟戊酸/甾醇/胆汁酸生物合成途径中调节人肝细胞模型中CYP3A和CYP2B6表达的特定代谢中间体。这些研究将提供有关广泛使用的一类药物的药理学的重要新信息，以及对诱导性 P450 表达的机制的重要见解。