Benzo[a]pyrene-induced chromatin organization and epigenomics mediated by SATB1

SATB1介导的苯并[a]芘诱导的染色质组织和表观基因组学

• 批准号: 9213517
• 负责人: Terumi Kohwi-Shigematsu
• 金额: $ 29.06万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-06 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9213517
• 关键词: Benzo; pyrene; induced; chromatin; organization

DESCRIPTION (provided by applicant): Environmental toxicants can induce changes in the epigenomic status of exposed cells, resulting in altered gene expression, which can consequently lead to human diseases such as cancer. The Aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, is expected to play a key role in this process upon exposure to these toxicants. However, how these epigenomic changes are brought about in response to environmental toxicant exposure is far from being understood. One major toxicant is the prototypical polycyclic aromatic hydrocarbon (PAH) benzo[a]pyrene (B[a]P) which is found in air pollution generated by incomplete combustion of organic materials. To understand important upstream events for implementing epigenomic status in response to environmental toxicants, we will study the effect of B[a]P on higher-order chromatin structure (such as chromatin looping formed via inter- or intra-chromosomal interactions). Epigenomic status and subsequent gene expression profiles of individual genes are governed at the level of higher-order chromatin structure. We will address the role of the genome organizer protein SATB1 in the process of conformational changes of chromatin induced by B[a]P. SATB1 can establish higher-order chromatin folding, affect the epigenomic status at hundreds of its target genes, and reprogram gene expression genome-wide in response to external signaling. Thus, we propose the hypothesis that SATB1 is a critical driver in executing the effects of environmental toxicants in affected cells at the level of higher-order chromatin structure. If so, the gene regulatory role of the ligand-activated AhR after B[a]P exposure would be greatly altered under the influence of SATB1. We will determine the effect of gene expression patterns in response to B[a]P exposure using our breast epithelial MCF10A tumor progression series, containing SATB1- expressing and non-expressing cells. We will determine genomic binding sites of AhR (and its associating partner, ARNT) and SATB1 by chromatin immunoprecipitation, followed by deep sequencing to find if any SATB1 and AhR-ARNT complex binding sites merge upon B[a]P exposure, and we will examine the biological consequences of B[a]P exposure of the cells expressing varying levels of SATB1. We aim to assess whether B[a]P exposure promotes malignancy to a degree dependent on the SATB1 levels in the exposed cells. The potential role of a genome organizer in controlling ligand-activated AhR after exposure to environmental toxicants has never been addressed to date, and testing this hypothesis will likely provide a valuable new perspective for the field of environmental health science.

描述（由申请人提供）：环境毒物可引起暴露细胞表观基因组状态的变化，导致基因表达改变，从而导致癌症等人类疾病。芳基碳氢化合物受体 (AhR) 是一种配体激活的转录因子，预计在暴露后的这一过程中发挥关键作用 对这些有毒物质。然而，这些表观基因组变化是如何因环境有毒物质暴露而发生的，目前尚不清楚。一种主要有毒物质是典型的多环芳烃 (PAH) 苯并[a]芘 (B[a]P)，它存在于有机材料不完全燃烧产生的空气污染中。为了了解针对环境毒物实施表观基因组状态的重要上游事件，我们将研究 B[a]P 对高级染色质结构（例如通过染色体间或染色体内相互作用形成的染色质环）的影响。单个基因的表观基因组状态和随后的基因表达谱受高阶染色质结构水平的控制。我们将探讨基因组组织蛋白 SATB1 在 B[a]P 诱导的染色质构象变化过程中的作用。 SATB1 可以建立高阶染色质折叠，影响数百个靶基因的表观基因组状态，并响应外部信号在全基因组范围内重新编程基因表达。因此，我们提出这样的假设：SATB1 是在高阶染色质结构水平上执行受影响细胞中环境毒物影响的关键驱动因素。如果是这样，则基因调控作用 B[a]P暴露后配体激活的AhR在SATB1的影响下会发生很大的改变。我们将使用我们的乳腺上皮 MCF10A 肿瘤进展系列（包含 SATB1 表达和非表达细胞）来确定基因表达模式对 B[a]P 暴露的影响。我们将通过染色质免疫沉淀来确定 AhR（及其相关伙伴 ARNT）和 SATB1 的基因组结合位点，然后进行深度测序，以确定是否有任何 SATB1 和 AhR-ARNT 复合体结合位点在 B[a]P 暴露后合并，我们将检查表达不同水平 SATB1 的细胞暴露于 B[a]P 的生物学后果。我们的目的是评估 B[a]P 暴露是否会在一定程度上促进恶性肿瘤，具体程度取决于暴露细胞中的 SATB1 水平。迄今为止，基因组组织者在暴露于环境毒物后控制配体激活的 AhR 中的潜在作用尚未得到解决，测试这一假设可能会为环境健康科学领域提供一个有价值的新视角。