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Novel Mechanism of aryl hydrocarbon receptor-mediated differential gene regulation

芳烃受体介导的差异基因调控新机制

基本信息

批准号：
9976506
负责人：
Aditya D Joshi
金额：
$ 12.3万
依托单位：
UNIVERSITY OF TEXAS MED BR GALVESTON
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-07-12 至 2020-08-27
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9976506
关键词：
ARNT gene ARNT protein Acetylation Acids Address Affect Agonist American Apoptosis Architecture Aryl Hydrocarbon Receptor Attenuated Binding Binding Proteins Biology CRISPR/Cas technology CYP11A1 gene CYP1A1 gene Cell Culture Techniques Cell Line Cell Nucleus Cells Chromatin Clustered Regularly Interspaced Short Palindromic Repeats Complex Cytoprotection DNA DNA Binding DNA Sequence Data Development Dioxins Epigenetic Process Estrogen receptor positive Ethanol Exhibits Future Gene Expression Gene Expression Regulation Genes Genetic Transcription Goals Hepatocyte Heterodimerization Histone H4 Histones In Vitro Intervention Libraries Ligand Binding Ligands Liver diseases Lysine Mass Spectrum Analysis Mediating Mediator of activation protein Metastasis-associated protein Modification Molecular Molecular Conformation Monitor Oxidative Stress Pathway interactions Peptide Signal Sequences Physiological Post-Translational Protein Processing Promoter Regions Property Proteins Quantitative Reverse Transcriptase PCR RNA Interference Reaction Reader Regulation Research Research Personnel Response Elements Role Signal Pathway Specificity Stress Testing Tetrachlorodibenzodioxin Therapeutic Tissue-Specific Gene Expression Toxic effect Transcriptional Regulation Tryptophan Up-Regulation Xenobiotic Metabolism Xenobiotics aryl hydrocarbon receptor ligand chromatin immunoprecipitation chromatin remodeling cofactor crosslink epigenetic regulation experimental study histone modification in vivo liver injury molecular targeted therapies novel promoter receptor binding recruit response screening stanniocalcin 2 stressor transcription factor translational research program

项目摘要

ABSTRACT Aryl hydrocarbon Receptor (AhR), a mediator of xenobiotic toxicity, is known to function as a ligand-activated transcription factor that binds to a xenobiotic response element (XRE, GCGTG motif) in association with its heterodimerization partner, the AhR nuclear translocator (Arnt) protein. This proposal is built on our observation that cinnabarinic acid (CA) mediated AhR-dependent induction of stanniocalcin 2 (stc2) attenuates stress induced apoptosis and protects against liver injury both in vitro and in vivo. stc2 induction was achieved in response to endogenous AhR agonist CA but not the classic exogenous AhR ligand 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD). Moreover, CA in contrast to TCDD, was unable to trigger prototypical AhR target gene, cyp1a1 in hepatocytes and did not regulate xenobiotic metabolism. Therefore, stc2 and cyp1a1 genes exhibit mutually exclusive agonist-specific AhR-mediated transcriptional responsiveness with distinct physiological consequences. As a part of my K01 research, we observed interaction of Metastasis-associated protein 2 (MTA2), a known chromatin remodeling protein, with AhR exclusively upon CA treatment. AhR-MTA2 complex was recruited only to stc2, but not cyp1a1 promoter. In addition, CA treatment was able to exhibit histone H4 lysine 5 acetylation specifically at stc2 promoter concomitant with AhR-MTA2 complex recruitment. Our preliminary studies identified that chromatin architecture in addition to the primary DNA sequence significantly contributes to the agonist-specific differential gene expression. Building on our preliminary studies this proposal tests the hypothesis that CA-specific AhR-dependent epigenetic modifications and chromatin restructuring dictates transcription regulation of stc2, which in turn is responsible for cytoprotection following liver injury. Specific Aim 1 of this application will profile CA and TCDD specific epigenetic modifications as well as will identify the readers-writers-erasers of the histone modifications recruited to the XRE bounds AhR-MTA2 complex. Specific Aim 2 will determine role of chromatin architecture in agonist specific stc2 regulation by using CRISPR/Cas9 gene editing. Specific Aim 3 will interrogate mechanism by which CA-triggered stc2 protects against ethanol-induced apoptosis by identifying downstream cytoprotective pathway components activated by stc2. Therefore, the objective of this application is to decode CA-specific AhR-mediated transcription regulation of stc2 and decipher its cytoprotective function. Given stc2’s involvement in cytoprotection against liver injury, understanding its CA-specific regulation may serve as a key to developing future molecular therapeutics targeting hepatic diseases.

抽象的芳基烃受体 (AhR) 是一种外源毒性介质，已知可作为配体激活的受体与异生物质反应元件（XRE、GCTGG 基序）结合的转录因子，与其相关异二聚化伙伴，AhR 核易位蛋白 (Arnt) 蛋白。该提案是建立在我们的观察到肉桂酸 (CA) 介导的 AhR 依赖性斯钙素 2 (stc2) 诱导减弱应激诱导细胞凋亡并在体外和体内防止肝损伤。 stc2感应已实现响应内源性 AhR 激动剂 CA，但不响应经典的外源性 AhR 配体 2,3,7,8- 四氯二苯并-对-二恶英（TCDD）。此外，与 TCDD 相比，CA 无法触发典型的 AhR 肝细胞中的靶基因 cyp1a1 不调节外源代谢。因此，stc2 和 cyp1a1 基因表现出相互排斥的激动剂特异性 AhR 介导的转录反应性，具有不同的生理后果。作为我的 K01 研究的一部分，我们观察到转移相关的相互作用蛋白 2 (MTA2)，一种已知的染色质重塑蛋白，仅在 CA 处理后与 AhR 结合。 AhR-MTA2 复合物仅招募到 stc2，而不招募到 cyp1a1 启动子。此外，CA 处理能够表现出组蛋白 H4 赖氨酸 5 乙酰化特异性在 stc2 启动子处，伴随着 AhR-MTA2 复合物的募集。我们的初步研究发现，除了初级 DNA 序列之外，染色质结构显着促进激动剂特异性差异基因表达。以我们的初步研究为基础该提案测试了 CA 特异性 AhR 依赖性表观遗传修饰和染色质的假设重组决定了 stc2 的转录调控，而 stc2 又负责细胞保护肝损伤。该应用程序的具体目标 1 还将分析 CA 和 TCDD 特定的表观遗传修饰这将识别招募到 XRE 边界 AhR-MTA2 的组蛋白修饰的读取器-写入器-擦除器复杂的。具体目标 2 将确定染色质结构在激动剂特异性 stc2 调节中的作用使用 CRISPR/Cas9 基因编辑。具体目标 3 将询问 CA 触发 stc2 的机制通过识别下游细胞保护途径成分来防止乙醇诱导的细胞凋亡由 stc2 激活。因此，本应用的目标是解码 CA 特定的 AhR 介导的 stc2 的转录调控并破译其细胞保护功能。鉴于 stc2 的参与细胞保护对抗肝损伤，了解其 CA 特异性调节可能是开发的关键未来针对肝病的分子疗法。