Novel in vivo regulatory mechanisms of human CYP3A4

人CYP3A4的新型体内调节机制

基本信息

批准号：
8656023
负责人：
Romi Ghose
金额：
$ 24.1万
依托单位：
UNIVERSITY OF HOUSTON
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-03-15 至 2016-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8656023
关键词：
3&apos Untranslated Regions Antibodies Binding Binding Sites Bioinformatics Biological Assay CYP3A4 gene Cardiovascular Diseases Cells Chemicals Chromatin Communicable Diseases Complex Cytochrome P450 Cytochrome P450 3A4 DNA DNase-I Footprinting Development Diabetes Mellitus Disease Down-Regulation Drug Interactions Endotoxins Enhancers Environment Enzymes Epigenetic Process Future Gene Expression General Transcription Factors Genome Goals High-Throughput Nucleotide Sequencing Human Image Immunoprecipitation In Vitro Individual Infection Inflammation Mediators Lead Ligands Lipopolysaccharides Liver Liver diseases Luciferases Malignant Neoplasms Maps Measures Mediating Messenger RNA MicroRNAs Microarray Analysis Modification Molecular Mus Nuclear Orphan Receptor Nuclear Receptors Patients Pharmaceutical Preparations Plasmids Post-Transcriptional Regulation Proteins RNA RNA-Protein Interaction Reaction Regulation Regulatory Element Rifampin Risk Role Safety Site Techniques base chromatin immunoprecipitation chromatin modification crosslink cytokine deep sequencing drug metabolism gel mobility shift assay genome-wide hepatocyte nuclear factor improved in vivo inflammatory marker mRNA Expression mutant novel pregnane X receptor prevent promoter protein expression public health relevance research study transcription factor

项目摘要

ABSTRACT. Cytochrome P450 (CYP) 3A4 is the most abundant CYP enzyme in the human liver, and it metabolizes ~60% of known drugs. CYP3A4-mediated drug metabolism is impaired in patients with infections, diabetes, cancer, cardiovascular diseases, liver disorders and many other diseases. Disruptions in drug metabolism in diseases are associated with induction of inflammatory markers and reductions in expression of CYP enzymes. Thus, in most patients, medications are exposed to a micro-environment where inflammatory mediators are activated. This increases the risks of drug-drug interactions and adverse drug reactions in these patients. The objective of this exploratory proposal is to perform genome-wide mapping and bioinformatics analysis to identify key regulators involved in down-regulation of human CYP3A4 enzymes in vivo. CYP3A4 gene expression is regulated by basal transcription factors as well as nuclear receptors (NRs). In vitro studies have shown that CYP3A4 expression is also regulated by microRNAs (miRNAs). Thus, down-regulation of CYP3A4 enzymes may be a cumulative effect of transcriptional and post-transcriptional modifications by transcription factors, NRs and/or miRNAs. Our central hypothesis is that down-regulation of CYP3A4 expression is controlled by transcription factor/NR-associated epigenetic modifications at the target chromatin as well as by changes in miRNA binding to CYP3A4 mRNA. The first aim of this proposal will examine the hypothesis that down- regulation of CYP3A4 gene is controlled by transcription factor/NR-associated epigenetic modifications at the target chromatin. The second aim will determine the role of miRNAs in down-regulation of CYP3A4 enzymes in vivo. CYP3A4 expression can be activated by diverse chemicals which induce NRs, including pregnane X receptor (PXR). On the other hand, CYP3A4 can be down-regulated by inflammatory mediators including cytokines and the bacterial endotoxin, lipopolysaccharide (LPS) which are associated with diseases. To identify the key regulators involved in alteration of CYP3A4 enzymes, our strategy is to utilize a combined approach of CYP3A4 induction by PXR ligand (e.g. PCN) and CYP3A4 down-regulation by LPS. The proposed studies using genome-based approaches can unravel novel regulatory elements which contribute to down-regulation of human CYP3A4 enzymes in vivo. These regulators can then be targeted to prevent undesirable effects of drugs due to changes in CYP3A4-mediated drug metabolism. Ultimately, this can lead to the development of new strategies to improve the safety of medications in individual patients.

抽象的。细胞色素 P450 (CYP) 3A4 是人体肝脏中最丰富的 CYP 酶，它代谢 ~60% 已知药物。 CYP3A4 介导的药物代谢在感染、糖尿病、癌症、心血管疾病、肝脏疾病和许多其他疾病。疾病中药物代谢的破坏与炎症标记物的诱导和 CYP 酶表达的减少有关。因此，在大多数患者的药物都暴露在炎症介质被激活的微环境中。这增加了这些患者药物相互作用和药物不良反应的风险。目标这个探索性提案的目的是进行全基因组作图和生物信息学分析，以确定关键参与体内人 CYP3A4 酶下调的调节因子。 CYP3A4 基因表达为受基础转录因子和核受体（NR）调节。体外研究表明 CYP3A4 的表达也受到 microRNA (miRNA) 的调节。因此，CYP3A4酶的下调可能是转录因子转录和转录后修饰的累积效应， NR 和/或 miRNA。我们的中心假设是 CYP3A4 表达的下调是由目标染色质的转录因子/NR 相关表观遗传修饰以及 miRNA 与 CYP3A4 mRNA 结合。该提案的第一个目标将检验以下假设： CYP3A4 基因的调控由转录因子/NR 相关的表观遗传修饰控制目标染色质。第二个目标是确定 miRNA 在下调 CYP3A4 酶的作用体内。 CYP3A4 表达可以被多种诱导 NR 的化学物质激活，包括孕烷 X 受体（PXR）。另一方面，CYP3A4 可以被炎症介质下调，包括与疾病相关的细胞因子和细菌内毒素、脂多糖（LPS）。识别参与 CYP3A4 酶改变的关键调节因子，我们的策略是利用以下组合方法 PXR 配体（例如 PCN）诱导 CYP3A4，LPS 下调 CYP3A4。拟议的研究使用基于基因组的方法可以揭示有助于下调的新调控元件人体内 CYP3A4 酶的变化。然后可以针对这些监管机构来防止不良影响由于 CYP3A4 介导的药物代谢的变化而导致药物失效。最终，这可以导致发展提高个体患者用药安全性的新策略。