Genetic Predictors of Human Liver CYP Expression & Activity

人类肝脏 CYP 表达的遗传预测因子

• 批准号: 8322839
• 负责人: ERIN G SCHUETZ
• 金额: $ 34.65万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8322839
• 关键词: Accounting; Affect; Area; CYP2C9 gene; CYP3A4 gene; Candidate Disease Gene; Complementary DNA; Complex; Cytochrome P450; Cytochromes b5; DNA Resequencing; Data; Dose; Gene Expression; Genes; Genetic; Genetic Polymorphism; Genetic Variation; Genomics; Genotype; Goals; Grant; Hepatic; Human; Immune response; Individual; Knowledge; Liver; Measures; Mediating; Medicine; Messenger RNA; Metabolism; NADPH-Ferrihemoprotein Reductase; Nucleotides; Pathway Analysis; Patients; Pharmaceutical Preparations; Pharmacogenetics; Pharmacotherapy; Phenotype; Public Health; Research; Resources; Sampling; Systems Biology; Tail; Testing; Time; Tissues; Toxic effect; Transcription Process; Validation; Variant; base; drug clearance; drug metabolism; enzyme activity; genetic variant; genome wide association study; improved; mRNA Expression; novel; public health relevance; response; tool; trait

DESCRIPTION (provided by applicant): The long-term goal of this research is to understand how genetic variation in four candidate genes influences hepatic cytochrome P450 (CYP) activity and mRNA expression. This is necessary because, despite considerable effort to identify cis CYP nucleotide diversity, there is still unexplained variability in host response to and toxicity from drug therapies that is significantly influenced by hepatic CYP gene mediated drug clearance. We propose that expression of CYPs is really a complex trait resulting from the combined effect of multiple polymorphisms interacting to regulate gene expression and enzyme activity. We propose that recent results from human liver GWAS integrated with systems biology based network analysis has created unprecedented opportunities in the pharmacogenetic research area by identifying novel candidate genes responsible for hepatic CYP variability. Specifically a recent study with our collaborators, exploited network and pathway analysis tools to illuminate the primary CYP network and the upstream regulators whose genetic variation perturbs expression of the downstream regulated CYPs. A major goal of this proposal is to extend these novel preliminary findings to identify the functional variation in candidate genes associated with altered CYP expression/activity. Our primary approach will be our historical phenotype to genotype analysis in human livers. In this approach, our initial goal is to use liver gene expression and activity as phenotypic measures and to deep resequence the phenotyped samples, particularly the tails of the phenotypic distribution in expression/activity and identify variants that account for phenotypic variability. The need for large and diverse sets of phenotyped samples is usually a limiting factor in implementing this approach. However, we have tissue from over 700 liver samples. Hundreds of these livers were recently part of a collaborative genome wide association study (GWAS #1) that included phenotyping for nine CYP activities. This application is unique in because we also have extensively phenotyped livers for validation available through independent GWAS #2 and 3 liver resources. We use a variety of experimental approaches to identify candidate gene genetic variation starting with deep resequencing of the cDNAs (Approach 1). This is followed in Approaches 2 and 3 that identify polymorphisms leading to altered mRNA processing and transcription, and ultimately altered mRNA expression of the candidate gene. For each approach we examine the association of polymorphisms to candidate gene mRNA expression and CYP activity and expression in liver GWAS#1 livers and test for replication in GWAS #2,3 livers. Approach 4 carries out required mechanistic studies to demonstrate how any variants change candidate gene mRNA expression. In total, these aims will fill an existing knowledge gap by identifying novel genetic contributors to variable CYP mediated drug metabolism. PUBLIC HEALTH RELEVANCE: CYPs oxidatively metabolize the majority of the orally effective drugs in use today. Nevertheless, despite many years of cis CYP pharmacogenetics, knowledge is still incomplete on the genetic factors influencing CYP mediated metabolism. This study is, for the first time, pursuing novel candidate gene regulators of CYPs identified through integration of pharmacogenetics with liver system biology. Successful completion of the studies proposed herein will improve public health by advancing "personalized medicine" through understanding of how polymorphisms in the candidate genes affect CYP expression and activity, and will ultimately improve genetically tailored patient dosing.

描述（由申请人提供）：这项研究的长期目标是了解四个候选基因的遗传变异如何影响肝细胞色素P450（CYP）活性和mRNA表达。这是必要的，因为尽管大力识别CIS CIP核苷酸多样性，但仍无法解释的宿主反应和药物疗法的毒性可变性，而药物疗法受到肝CYP基因介导的药物清除率的显着影响。我们提出，CYP的表达确实是由多态性相互作用以调节基因表达和酶活性的多态性的综合作用而产生的复杂特征。我们建议，与基于系统生物学的网络分析相结合的人类肝脏GWA的最新结果通过识别负责肝CYP变异性的新型候选基因，从而在药物遗传学研究领域创造了前所未有的机会。特别是与我们的合作者，利用网络和途径分析工具的最新研究，以阐明主要的CYP网络和上游调节器，其遗传变异会导致下游调节的CYP表达。该建议的主要目标是扩展这些新颖的初步发现，以识别与CYP表达/活性改变有关的候选基因的功能变化。我们的主要方法将是我们对人肝脏基因型分析的历史表型。在这种方法中，我们的最初目标是将肝脏基因表达和活性用作表型措施，并深深地重新分配表型样品，尤其是表达/活性中表型分布的尾巴，并识别说明表型变异性的变体。对大量和多样化的表型样品的需求通常是实施这种方法的限制因素。但是，我们有来自700多个肝样品的组织。这些肝脏中有数百个最近是一项合作基因组广泛协会研究（GWAS＃1）的一部分，其中包括九种CYP活动的表型。该应用程序是独一无二的，因为我们还具有广泛的表型肝脏，可通过独立的GWAS＃2和3肝脏资源获得验证。我们使用各种实验方法来鉴定候选基因遗传变异，从cDNA的深度重新配置开始（方法1）。在方法2和3中遵循这一点，这些方法鉴定出导致mRNA处理和转录改变的多态性，并最终改变了候选基因的mRNA表达。对于每种方法，我们检查了肝脏GWAS＃1肝脏中多态性与候选基因mRNA和CYP活性以及表达的关联，并在GWAS＃2,3肝脏中进行了复制。方法4进行了必要的机械研究，以证明任何变体如何改变候选基因mRNA表达。总的来说，这些目标将通过确定可变CYP介导的药物代谢的新遗传因素来填补现有的知识差距。 公共卫生相关性：CYPS氧化代谢当今使用的大多数口服有效药物。然而，尽管CIS CYP药物遗传学多年，但知识仍然对影响CYP介导的代谢的遗传因素仍然不完整。这项研究是首次追求通过将药物遗传学与肝系统生物学整合而识别的CYP的新型候选基因调节剂。通过了解候选基因中的多态性如何影响CYP的表达和活动，成功地完成了本文提出的研究将改善“个性化医学”，并最终改善基因定制的患者给药。