Novel in vivo regulatory mechanisms of human CYP3A4

人CYP3A4的新型体内调节机制

• 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
• 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' 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

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是人肝中最丰富的CYP酶，它代谢约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，肝病和许多其他疾病。疾病中药物代谢的破坏 与炎症标记的诱导和CYP酶表达的降低有关。因此，在 大多数患者，药物都暴露于微观环境中，在该环境中激活了炎症介质。 这增加了这些患者的药物相互作用和药物反应不良的风险。目标 该探索性建议是进行全基因组映射和生物信息学分析以识别关键 参与体内人类CYP3A4酶下调的调节剂。 CYP3A4基因表达是 由基础转录因子和核受体（NRS）调节。体外研究表明 CYP3A4表达也受microRNA（miRNA）调节。因此，CYP3A4酶的下调 可能是转录因子的转录和转录后修饰的累积效应， NRS和/或miRNA。我们的中心假设是CYP3A4表达的下调受到控制 转录因子/NR相关的表观遗传修饰在靶染色质以及通过变化 miRNA与CYP3A4 mRNA结合。该提议的第一个目的将研究以下假设。 CYP3A4基因的调节受转录因子/NR相关的表观遗传修饰的控制 靶染色质。第二个目标将决定miRNA在下调CYP3A4酶在中的作用 体内。 CYP3A4表达可以通过诱导NR的各种化学物质激活，包括怀孕X 受体（PXR）。另一方面，CYP3A4可以被包括 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酶改变的关键调节剂，我们的策略是利用一种合并的方法 PXR配体（例如PCN）和CYP3A4下调LPS的CYP3A4诱导。提出的研究 使用基于基因组的方法可以揭示新的调节元素，从而有助于下调 人体CYP3A4酶的体内。然后可以针对这些调节器，以防止 由于CYP3A4介导的药物代谢的变化而引起的药物。最终，这可能导致 提高各个患者药物安全性的新策略。