PAHs: Balance of Detoxication vs Metabolic Activation

PAH：解毒与代谢激活的平衡

• 批准号: 7188660
• 负责人: Daniel W. Nebert
• 金额: $ 34.52万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-17 至 2010-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7188660
• 关键词: Adipose tissue; Aromatic Hydrocarbons; Aromatic Polycyclic Hydrocarbons; Benzo(a)pyrene; Bile fluid; Binding; Blood; Blood Vessels; Bone Marrow; Breathing; CYP1A1 gene; CYP1A2 gene; CYP1B1 gene; Carbon; Cells; Chylomicrons; Clinical Research; Cultured Cells; Cytochrome P450; Cytochromes; Dioxins; Distal; Drug Kinetics; Drug Metabolic Detoxication; Environmental Pollutants; Enzymes; Equilibrium; Exhibits; Food; Fright; General Population; Genes; Genetic Transcription; Genome; Hand; Haplotypes; Health; Hepatocyte; Human; Immune; Intervention; Intestines; Kinetics; Knock-out; Knockout Mice; Knowledge; Laboratories; Ligands; Liver; Lymph; Lymphatic; Malignant Neoplasms; Marrow; Mesentery; Metabolic Activation; Metabolism; Mus; Mutagenesis; Nitrosamine Metabolism; Nitrosamines; Oral; Organ; Parents; Pharmaceutical Preparations; Pharmacologic Substance; Portal System; Portal vein structure; Principal Investigator; Property; Proteins; Recycling; Resistance; Role; Route; Spleen; Testing; Tissues; Toxic effect; cigarette smoking; concept; detoxication; genotoxicity; intestinal epithelium; macrophage; programs; prototype; receptor; uptake

DESCRIPTION (provided by applicant): Polycyclic aromatic hydrocarbons (PAHs), nitrosamines, and N-heterocyclics are present in combustion products, e.g. grilled foods & cigarette smoke. Cytochromes P450 1A1 & 1B1 (CYP1A1, CYP1B1) are responsible for the metabolism of numerous PAHs, the prototype of which is benzo[a]pyrene (BaP). CYP1A2 is responsible for metabolizing nitrosamines and N-heterocyclics, but also PAHs (in particular, BaP) to a lesser extent. Using Cyp1a1(-/-) and Cyp1b1(-/-) knockout mice, we have shown that CYP1A1 is more important in detoxication than metabolic activation, whereas CYP1B1 causes metabolic activation of BaP to unwanted reactive intermediates. In other words, CYP1A1 is more good than bad in the intact mouse ingesting BaP, and CYP1B1 is more bad than good in the intact mouse administered PAHs by various routes. The importance of mesenteric lymphatics vs. the portal system (mesenteric blood vessels, liver, bile) is not known for oral BaP. This lab now has seven-all three single, all three double, and the one triple-Cyp1 knockout mouse lines. Our hypothesis is: lymph BaP uptake and CYP1B1 in distal tissues (e.g. immune cells, spleen, and bone marrow) are the principal causes of oral BaP toxicity, whereas inducible CYP1A1 in liver and intestine is the principal cause of BaP detoxication. In this proposed project, we therefore will: [a] identify and determine the amounts of metabolites vs. unchanged parent BaP in mesenteric lymph, portal vein blood, liver, and bile in wild-type and all seven Cyp1 knockout mouse lines, and the role and mechanism of chylomicrons in delivering BaP to target organs; [b] generate liver- and intestinal epithelium-specific Cyp1a1 conditional knockout lines; [c] replace the Cyp1b1 gene (in the genome) with the Cyp1a1 gene, and vice versa; and [d] repeat our BaP pharmacokinetics studies (see [a]) in these four newly generated mouse lines. Understanding the tissue- specific roles for each of the three CYP1 enzymes in the intact mouse receiving oral BaP will provide us with a greater understanding of BaP detoxification vs. metabolic activation. We expect this knowledge will provide a blueprint for understanding the mechanisms of elimination vs. dissemination of ingested BaP and will be informative in clinical studies in which we would determine which haplotypes of these three human genes might be associated with resistance vs. sensitivity to PAH-induced toxicity and cancer.

描述（由申请人提供）：燃烧产物中存在多环芳烃（PAHS），硝基胺和N-杂环的。烤食物和香烟烟。细胞色素P450 1A1和1B1（CYP1A1，CYP1B1）负责许多PAH的代谢，其原型是苯并[A] pyrene（BAP）。 CYP1A2负责代谢亚硝基胺和N-杂环，但也有PAHS（尤其是BAP）的代谢。使用CYP1A1（ - / - ）和CYP1B1（ - / - ）基因敲除小鼠，我们表明CYP1A1在排毒中比代谢激活更为重要，而CYP1B1导致BAP代谢激活对不需要的反应性中间体。换句话说，在完整的鼠标摄入BAP中，CYP1A1比坏的好，而CYP1B1在完整的小鼠通过各种路线施用的PAH中更糟糕。肠系膜淋巴机与门户系统（肠系膜血管，肝脏，胆汁）的重要性不以口服BAP而闻名。现在，该实验室拥有7个全部三个单打，全部三个双打和一个Triple-CYP1敲除鼠标线。我们的假设是：远端组织（例如免疫细胞，脾脏和骨髓）中淋巴结吸收和CYP1B1是口服BAP毒性的主要原因，而肝脏中可诱导的CYP1A1，而Intestine则是BAP解毒的主要原因。因此，在这个拟议的项目中，我们将：[a]识别并确定肠系膜淋巴，门静脉血液，肝脏和胆汁中的代谢产物与未改变的父母BAP的量，以及所有七个CYP1敲除小鼠线条，以及所有在将囊肿的作用和机构在向目标机构传递给目标机构中的作用和机构； [b]产生肝和肠上皮特异性CYP1A1条件敲除线； [C]用CYP1A1基因代替CYP1B1基因（在基因组中），反之亦然； [d]在这四个新生成的小鼠系中重复我们的BAP药代动力学研究（参见[A]）。了解完整的小鼠接受口腔BAP中三种CYP1酶的组织特异性作用将使我们对BAP解毒与代谢激活有更深入的了解。我们预计，这些知识将为理解消除的机制与摄入的BAP的传播提供蓝图，并在临床研究中提供信息，我们将确定这三个人类基因的哪些单倍型可能与对PAH诱导的毒性和毒性和癌症的敏感性有关。