INTERACTION BETWEEN AH RECEPTOR AND NF-KB PATHWAYS

AH 受体与 NF-KB 通路之间的相互作用

• 批准号: 6042158
• 负责人: YANAN TIAN
• 金额: $ 20.25万
• 依托单位: UNIV OF MED/DENT NJ-R W JOHNSON MED SCH
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-01 至 2003-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6042158
• 关键词: apoptosis; aromatic hydrocarbon receptor; benzopyrenes; biological signal transduction; carbopolycyclic compound; cytochrome P450; cytokine; dioxins; environmental toxicology; gel mobility shift assay; nuclear factor kappa beta; pathologic process; protein localization; protein protein interaction; transcription factor; transfection

DESCRIPTION: (Adapted from the Investigator's Abstract) Polyhalogenated and polycyclic aromatic hydrocarbons, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and benzo(a)pyrene, are ubiquitous, persistent environmental contaminants causing toxic responses in humans and wildlife. Most of the toxic effects induced by these compounds are mediated by the aryl hydrocarbon receptor (AhR). Upon binding to ligands, the AhR translocates into the nucleus and binds to enhancer sequences causing alterations of gene expression. However, it is not known what connects this action to the rather broad range, yet distinct toxic responses induced by TCDD and related compounds. The investigator's preliminary studies demonstrated physical association and functional, mutual repression between AhR and NF-kB. Because NF-kB is a pleiotropic transcription factor involved in many physiological functions that are known to be affected by TCDD, the AhR-mediated suppression of NF-kB offers a mechanism for hitherto poorly understood TCDD toxicity. Remarkably, the suppression of AhR by NF-kB also offers an underlying mechanism for cytokine-induced suppression of cytochrome P450s (such as CYP1A1, 1A2). To further investigate the AhR/NF-kB interaction, the investigator proposes three specific aims: (1) to define the interacting domains of the AhR and NF-kB; (2) to analyze the functional interaction between AhR and NF-kB, and modulation of this interaction by other protein factors such as ARNT and transcription coactivators, such as p300/CBP; (3) to use the AhR (-/-) mouse and dominant negative suppressor of the NF-KB to examine the physiological effects of AhR/NF-kB interaction on the programmed cell death which leads to TCDD-induced thymus atrophy, as well as to examine cytokine-induced suppression of cytochrome P450s, which leads to decreased ability to metabolize xenobiotics. The functional significance of AhR/NF-KB interaction will be tested by the ability of proteins to interfere with each other in promoter binding. This will be tested by electrophoretic mobility shift assays and transient transfection assays. AhR and NF-kB proteins will be labeled with green fluorescence protein to detect effects of AhR/NF-kB interaction on their respective nuclear localization. The importance of this proposed research is further accentuated by the finding that many commonly consumed vegetables contain organic compounds, such as indole-3-carbinol and its derivatives, which also bind to AhR with high affinity. The physiological effects of these compounds, whether harmful or beneficial, are almost completely unknown. The studies proposed will increase our understanding of the role AhR plays in normal physiology, as well as in pathology induced by TCDD and like compounds.

描述：（改编自研究者的摘要）多卤代和 多环芳烃，例如2,3,7,8-四氯二苯并-对二恶英 (TCDD) 和苯并(a)芘是普遍存在的、持久存在的环境污染物 对人类和野生动物造成毒性反应的污染物。大部分有毒 这些化合物引起的效应是由芳基烃介导的 受体（AhR）。与配体结合后，AhR 易位到细胞核中 并与增强子序列结合，导致基因表达的改变。 然而，尚不清楚这一行动与相当广泛的范围有何联系， 然而，TCDD 和相关化合物会引起明显的毒性反应。 研究人员的初步研究证明了物理关联和 AhR 和 NF-kB 之间功能性的相互抑制。因为 NF-kB 是 多效性转录因子参与多种生理功能 已知受 TCDD 影响，AhR 介导的 NF-kB 抑制提供 迄今为止人们对 TCDD 毒性的机制知之甚少。值得注意的是， NF-kB 对 AhR 的抑制也提供了一个潜在机制 细胞因子诱导的细胞色素 P450（例如 CYP1A1、1A2）抑制。 为了进一步研究 AhR/NF-kB 相互作用，研究者提出 三个具体目标：(1) 定义 AhR 和 核因子kB； (2)分析AhR和NF-kB之间的功能相互作用，以及 通过其他蛋白质因子（例如 ARNT 和 转录辅激活因子，例如p300/CBP； (3) 使用AhR (-/-)鼠标 和 NF-KB 的显性失活抑制子来检查生理学 AhR/NF-kB 相互作用对程序性细胞死亡的影响，从而导致 TCDD 诱导的胸腺萎缩，以及检查细胞因子诱导的抑制 细胞色素 P450 的减少，导致代谢能力下降 异生素。 AhR/NF-KB 相互作用的功能意义是 通过启动子中蛋白质相互干扰的能力进行测试 绑定。这将通过电泳迁移率变化分析进行测试， 瞬时转染测定。 AhR 和 NF-kB 蛋白将被标记 绿色荧光蛋白检测 AhR/NF-kB 相互作用对其的影响 各自的核定位。 这一发现进一步强调了这项拟议研究的重要性 许多常用蔬菜含有有机化合物，例如 indole-3-carbinol 及其衍生物，也以高浓度与 AhR 结合 亲和力。这些化合物的生理作用，无论是有害还是 有益的，几乎完全未知。拟议的研究将增加 我们对 AhR 在正常生理学以及 由 TCDD 和类似化合物引起的病理学。