Signaling of the Pregnane X Receptor

孕烷 X 受体的信号传导

• 批准号: 7831855
• 负责人: Bingfang Yan
• 金额: $ 10.29万
• 依托单位: UNIVERSITY OF RHODE ISLAND
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7831855
• 关键词: Attenuated; Base Sequence; Be++ element; Beryllium; Cardiovascular Diseases; Cells; Cytochrome P450 3A4; Disease; Elements; Event; Experimental Designs; Functional RNA; Funding; Gene Expression; Genes; Hand; Human; Individual; Inflammation; Inflammation Mediators; Interleukin-6; Kinetics; Ligands; Lipopolysaccharides; Location; Malignant Neoplasms; Mediating; Messenger RNA; MicroRNAs; Molecular; Monitor; Nucleotides; Pharmaceutical Preparations; Play; RNA Polymerase II; Rattus; Recovery; Repression; Research Design; Research Project Grants; Role; Signal Transduction; Site; TATA Box; Testing; To specify; Transactivation; Transcript; Transcription Initiation Site; Translations; United States National Institutes of Health; Work; abstracting; attenuation; base; chemical elimination; cytokine; design; drug metabolism; expectation; mutant; parent grant; pregnane X receptor; promoter; public health relevance; rat CYP3A23 protein; receptor expression; response

DESCRIPTION (provided by applicant): Yan, Bingfang ABSTRACT This is a revision application in response to the announcement NOT-OD-09-058: NIH Announces the Availability of Recovery Act Funds for Competitive Revision Applications This revision application proposes a set of studies to extend the specific aims of the parent grant. The focus of the parent grant, presented as two specific aims, is to elucidate signaling events associated with the pregnane X receptor (PXR), a master regulator on the expression of many chemical elimination genes such as cytochrome P450 3A4 (CYP3A4) in humans and CYP3A23 in rats. Interestingly, the CYP3A23 but not the CYP3A4 proximal promoter responds robustly to a PXR ligand, although a functional PXR element is present in both CYP3A4 and CYP3A23 proximal promoters. Instead, the CYP3A4 proximal promoter coordinates with other upstream PXR elements and confers transactivation activity. Sequence comparison reveals that the CYP3A4 promoter, compared with CYP3A23, has the PXR element 30 bases farther from the transcription starting site. In addition, the CYP3A4 but not CYP3A23 promoter has an HNF3/CEBP site in front of the PXR element. The PXR-mediated trans- activation, on the other hand, is markedly attenuated by cytokines such as interleukin-6 (IL-6). microRNA-511 (miR-511), highly induced by IL-6, diminishes PXR transactivation. miRs are known to silence gene expression through sequence pairing with their target mRNAs. The proposed studies are designed to test the hypotheses that the PXR transcript is a sequence-specific target of miR-511, and the physical location of the PXR element and the presence of the HNF3/CEBP site contribute significantly to the inability of the CYP3A4 proximal promoter to effectively respond to PXR-transactivation. To define the potential role of the physical location or the interference of the HNF3/CEBP site, mutants will be prepared to disrupt the HNF3/CEBP site, relocate the PXR element closer to the transcription starting site, or both. These mutants will be tested for increased ability to respond to PXR transactivation. To determine the molecular action of miR-511 to decrease PXR expression, cells will be transfected with miR-511 and the levels of PXR mRNA and its translation efficiency will be monitored. In addition, the sequence supporting the action of miR-511 will be located and the role of miR-511 in the suppression of PXR by IL-6 will be established. Overall, the studies in the revision application represent significant expansion of the original aims in the parent grant. Importantly, these studies are closely integrated into the studies in the parent grant, and together, they will provide more comprehensive understanding on the expression of drug elimination genes regarding species-dependent transactivation and altered expression during inflammation. PUBLIC HEALTH RELEVANCE: The capacity of drug elimination is altered by co-administration of other drugs and disease status such as inflammation. The revision application proposes a set of studies to reveal the underlying mechanisms on how and to which extent the drug-eliminating capacity of an individual is altered by co-administered drugs or inflammatory mediators.

描述（由申请人提供）：Yan，Bingfang摘要这是一项修订申请，以响应公告而非OD-09-058：NIH宣布恢复ACT基金用于竞争性修订申请的可用性，此修订申请提出了一组研究，以扩大父母赠款的特定目标。作为两个特定目的的父授予的重点是阐明与妊娠X受体（PXR）相关的信号传导事件，这是一种针对许多化学消除基因的表达的主要调节剂，例如在人类中和大鼠中人类和CYP3A23的细胞色素P450 3A4（CYP3A4）。有趣的是，尽管CYP3A4和CYP3A23近端启动子均存在功能性PXR元件，但CYP3A23而不是CYP3A4近端启动子对PXR配体的反应强烈。取而代之的是，CYP3A4近端启动子与其他上游PXR元素坐标，并赋予反式激活活性。序列比较表明，与CYP3A23相比，CYP3A4启动子的PXR元件30碱基远离转录起始位点。此外，CYP3A4而不是CYP3A23启动子在PXR元素前具有HNF3/CEBP位点。另一方面，PXR介导的转移激活显着衰减，例如白介素-6（IL-6）。 MicroRNA-511（miR-511），高度由IL-6诱导，可减少PXR反式激活。已知MIR通过序列配对与其靶mRNA来沉默基因表达。拟议的研究旨在测试PXR转录本是miR-511的序列特异性靶标的假设，PXR元素的物理位置以及HNF3/CEBP位点的存在显着促进CYP3A4近端启动子的无能为力，从而对PXR-Transansactivation有效响应。为了定义物理位置的潜在作用或HNF3/CEBP位点的干扰，将准备突变体破坏HNF3/CEBP位点，将PXR元素重新安置到更接近转录起始位点的PXR元素，或两者兼而有之。这些突变体将被测试，以提高对PXR反式激活的反应能力。为了确定miR-511降低PXR表达的分子作用，将用miR-511转染细胞，并将监测PXR mRNA的水平及其平移效率。此外，将确定支持miR-511作用的序列，并将确定miR-511在抑制IL-6抑制PXR中的作用。总体而言，修订应用程序中的研究代表了父母赠款中原始目标的显着扩展。重要的是，这些研究紧密整合到了父授予的研究中，它们将共同对消除药物消除基因的表达提供有关物种依赖性反式激活和炎症过程中表达改变的更全​​面的理解。 公共卫生相关性：消除药物的能力会因其他药物和疾病状态（例如炎症）的共同管理而改变。修订申请提出了一系列研究，以揭示有关如何以及在何种程度上通过共同管理的药物或炎症介体改变了个体的药物灭绝能力的基本机制。