Novel ARNT-mediated Regulatory Paradigm of AHR Signaling

新型 ARNT 介导的 AHR 信号调节范式

基本信息

批准号：
9477928
负责人：
Casey W Wright
金额：
$ 34.88万
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：
2016
资助国家：
美国
起止时间：
2016-06-01 至 2021-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9477928
关键词：
ARNT gene Affect Affinity Alternative Splicing Amino Acids Antigen-Presenting Cells Aromatic Hydrocarbons Aryl Hydrocarbon Receptor Autoimmune Diseases Autoimmune Process Binding CD4 Positive T Lymphocytes CRISPR/Cas technology Cancer Cell Growth Cells Cellular biology Complex Cytoplasmic Receptors DNA Data Development Diet Dioxins EMSA Enhancers Environmental Pollution Event Exhibits Future Gatekeeping Gene Targeting Genetic Transcription Goals Hematopoiesis Immune Immune Tolerance Immune signaling Immunotherapy Individual Knock-out Laboratories Lentivirus Vector Ligand Binding Ligands Light Lymphocyte Lymphoma Malignant Neoplasms Malignant lymphoid neoplasm Mediating Molecular Mus Mutate NF-kappa B Nuclear Nuclear Translocation Organ Outcome Phosphorylation Phosphorylation Site Physiological Process Protein Isoforms RNA Polymerase II RNA Splicing Receptor Signaling Recruitment Activity Regulation Research Role Signal Pathway Signal Transduction Sum System T cell differentiation T-Lymphocyte Techniques Testing Tetrachlorodibenzodioxin Tissues Toxic Environmental Substances Transactivation Transgenic Mice Tryptophan Work Xenobiotics aryl hydrocarbon receptor ligand base cell growth cell type chromatin immunoprecipitation cofactor experimental study immunoregulation in vivo innovation mouse model mutant novel prevent public health relevance receptor binding receptor function receptor-mediated signaling reconstitution response therapy development transcription factor

项目摘要

DESCRIPTION (provided by applicant): AHR is a cytoplasmic receptor that has affinity for numerous xenobiotic ligands, which include halogenated aromatic hydrocarbons such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), one of the most potent AHR activators, and AHR signaling mediates the detrimental effects of environmental contaminants on body tissues and organs. Ligand binding induces nuclear translocation of AHR and interaction with the AHR binding partner, aryl hydrocarbon receptor nuclear translocator (ARNT), allowing recognition of specific DNA enhancer sequences. More recently endogenous and natural AHR ligands, such as tryptophan metabolites and dietary compounds, have been identified. These ligands induce AHR-mediated immunomodulatory effects such as controlling normal T cell differentiation and immune tolerance. However, little is known about the role of ARNT in AHR immune signaling. Initial studies by our laboratory, and others, into the regulatory role of ARNT in AHR-mediated immunomodulation have suggested that ARNT is an integral cofactor in different immune signaling pathways, including AHR and NF-κB signaling. ARNT is often described in AHR signaling as a constitutively expressed, non-regulated, nuclear binding partner for AHR. However, our data challenge this assumption and show that the actual regulatory paradigm is more intricate. For instance, ARNT is expressed as two isoforms, isoform 1 and 3, which differ in only 15 amino acids present in isoform 1. Despite their sequence similarity, we have found that the ARNT isoforms appear to have opposing functions in AHR signaling. Intriguingly, the extra 15 amino acids in isoform 1 include a unique phosphorylation site, where we have observed TCDD-induced phosphorylation. Furthermore, we find that the phosphorylation of ARNT isoform 1 is crucial for the recruitment of RNA polymerase II and transactivation of AHR/ARNT target genes. We predict that ARNT activity is a function of both unique phosphorylation of isoform 1 and the given isoform ratio within a particular cell type, which in turn is likely important for regulating the magnitude/outcome of the AHR response. To investigate our hypothesis we propose to 1) Define a comprehensive molecular framework for AHR regulation by the ARNT isoforms, 2) Examine the role of AHR activity, as governed by the ARNT isoforms, in lymphoma cell growth, and 3) Characterize the regulation of AHR signaling by ARNT isoforms in vivo. Ultimately, these studies will lay the groundwork for ARNT-based therapies such as splice modulation as a means of manipulating the ARNT isoforms to control AHR signaling in autoimmune diseases and cancer.

描述（由申请人提供）：AHR 是一种细胞质受体，对多种外源配体具有亲和力，其中包括卤代芳香烃，例如 2,3,7,8-四氯二苯并-对二恶英 (TCDD)，它是最有效的 AHR 之一激活剂和 AHR 信号传导介导环境污染物对身体组织和器官的不良影响。配体结合诱导 AHR 的核易位以及与 AHR 的相互作用。 AHR 结合伴侣，芳基碳氢化合物受体核转位子 (ARNT)，可识别特定的 DNA 增强子序列，最近已鉴定出内源性和天然 AHR 配体，例如色氨酸代谢物和膳食化合物，这些配体可诱导 AHR 介导的免疫调节作用。然而，我们实验室和其他人对 ARNT 在 AHR 免疫信号传导中的调节作用知之甚少。 AHR 介导的免疫调节表明 ARNT 是不同免疫信号传导途径（包括 AHR 和 NF-κB 信号传导）中不可或缺的辅助因子，ARNT 通常在 AHR 信号传导中被描述为 AHR 的组成型表达、非调节性核结合伴侣。我们的数据挑战了这一假设，并表明实际的监管范式更加复杂，例如，ARNT 表达为两种同工型，即同工型 1 和 3，其差异仅在于同工型中存在的 15 个氨基酸。 1. 尽管它们的序列相似，但我们发现 ARNT 亚型在 AHR 信号传导中似乎具有相反的功能。有趣的是，亚型 1 中额外的 15 个氨基酸包括一个独特的磷酸化位点，我们在该位点观察到 TCDD 诱导的磷酸化。我们发现 ARNT 亚型 1 的磷酸化对于 RNA 聚合酶 II 的募集和 AHR/ARNT 靶基因的反式激活至关重要，我们预测 ARNT 活性。是同工型 1 的独特磷酸化和特定细胞类型内给定同工型比率的函数，这反过来可能对于调节 AHR 反应的幅度/结果很重要。为了研究我们的假设，我们建议 1) 定义一个综合的。 ARNT 同工型对 AHR 调节的分子框架，2) 检查由 ARNT 同工型控制的 AHR 活性在淋巴瘤细胞生长中的作用，以及 3) 表征 AHR 信号传导的调节最终，这些研究将为基于 ARNT 的疗法奠定基础，例如剪接调节作为操纵 ARNT 亚型以控制自身免疫性疾病和癌症中的 AHR 信号传导的手段。