Elucidating epigenetic mechanisms of cellular cadmium toxicity

阐明细胞镉毒性的表观遗传机制

基本信息

批准号：
10266094
负责人：
David Benner Lombard
金额：
$ 7万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-09-21 至 2022-04-08
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10266094
关键词：
Acetylation Acute Affect Apoptosis Arts Automobile Driving Biological Bromodomain Cadmium Cell Death Cell Survival Cells Chemicals Chromatin Clinical Consumption Cultured Cells DNA Data Defect Drug Targeting Environmental Pollutants Epigenetic Process Epithelial Cells Excretory function Exposure to Fibroblasts Food Contamination Food Supply Foundations Gene Expression Gene Expression Profile Generations Genes Goals Half-Life Histologic Histone Acetylation Histone Deacetylase Inhibitor Histones Human Impairment Individual Industrialization Inflammation Kidney Link Liver Lung Lysine Mammalian Cell Measures Medical Methylation Mission Mitochondria Molecular Mus Occupational Organ Oxidation-Reduction Pancreas Pathogenicity Pathologic Pathway interactions Post-Translational Protein Processing Public Health Reactive Oxygen Species Renal function Resistance Respiration Risk Serum Markers Site Stress Techniques Testing Testis Tissues Toxic effect Toxicology Tubular formation United States National Institutes of Health Vorinostat Work absorption base bone carcinogenesis cell injury cellular targeting drinking water high throughput screening histone modification improved in vivo inhibitor/antagonist innovation insight interest kidney dysfunction mitochondrial metabolism nephrotoxicity new therapeutic target novel pollutant programs protective effect reproductive response screening small molecule targeted agent tissue injury transcriptome sequencing transcriptomics urinary

项目摘要

Abstract Cadmium (Cd) is a widespread environmental pollutant that affects millions of individuals worldwide. Cd exposure in humans occurs most often through Cd’s many industrial applications, or consumption of contaminated food. Due to its extremely extended biological half-life, Cd persists for decades in tissues, primarily in the liver and kidneys. Cd exerts numerous deleterious effects, including bone, reproductive, neurodevelopmental, and pulmonary toxicities, and carcinogenesis. The kidneys are the major target of Cd toxicity, particularly the proximal tubular epithelial cells, injury to which hampers tubular reabsorption. Despite the many sequelae associated with Cd exposure in humans, specific molecular mechanisms of Cd toxicity are poorly understood, and no specific therapies exist to mitigate the effects of Cd exposure. Via unbiased high- throughput screening, we identified a previously unknown ability of multiple chemically distinct histone deacetylase inhibitors (HDACi) and Bromodomain and Extra-Terminal motif inhibitors (BETi) to rescue acute cellular Cd toxicity. The long-term goal of these studies is to elucidate novel aspects of the cellular and molecular mechanisms of Cd toxicity. The objectives of this application are: i) to evaluate changes in gene expression and chromatin acetylation (Ac) occurring in response to Cd exposure in cultured cells and the kidney, and their potential rescue by HDACi or BETi treatment; and ii) to test the ability of HDACi and BETi to mitigate Cd induced nephrotoxicity. The central hypothesis of this application is that the interplay between histone Ac and mitochondrial metabolism represents a key functional target of Cd toxicity in mammalian cells. The rationale for this application is our novel foundational data demonstrating that Cd exposure induces a reduction in mitochondrial function and histone Ac. Crucially, treatment with HDACi and BETi rescue Cd-induced defects in mitochondrial respiration, metabolite levels, and cell viability. These findings implying that histone Ac and mitochondrial function are important functional cellular targets of Cd. The work will take place in the context of two Specific Aims. First, via RNA-seq and chromatin profiling, functionally important genes and pathways targeted by Cd, and rescued by an HDACi and a BETi, will be identified in cultured fibroblasts. Second, rescue of Cd-induced nephrotoxicity by an HDACi and a BETi will be evaluated in vivo in mice. We will compare the gene expression signatures of Cd-exposed kidney and fibroblasts, to identify core gene expression programs driving Cd toxicity, particularly focusing on those rescued by HDACi and BETi. The approach is innovative, in that mechanistic links between epigenetic alterations induced by Cd and its biological effects have yet to be conclusively established, and the use of small molecules directed against histone Ac or epigenetic perturbations more generally as treatments for Cd toxicity has not previously been described. The work is significant, since there is an unmet need for improved, mechanism-treatments for Cd toxicity. These studies may establish histone Ac as a novel therapeutic target for Cd toxicity.

抽象的镉 (Cd) 是一种广泛存在的环境污染物，影响着全世界数百万人。人类接触镉最常发生在许多工业应用中，或者消费由于镉的生物半衰期极长，它会在组织中（主要是组织）持续存在数十年。镉对肝脏和肾脏产生许多有害影响，包括骨骼、生殖、神经发育、肺部毒性和致癌作用肾脏是镉的主要靶标。毒性，特别是近端肾小管上皮细胞的损伤，阻碍了肾小管的重吸收。人类与镉暴露相关的许多后遗症，镉毒性的具体分子机制是人们对此知之甚少，并且没有特定的疗法可以通过无偏见的高剂量来减轻镉暴露的影响。通过通量筛选，我们发现了多种化学上不同的组蛋白的先前未知的能力脱乙酰酶抑制剂（HDACi）和布罗莫结构域和末端基序抑制剂（BETi）可挽救急性这些研究的长期目标是阐明细胞和细胞毒性的新方面。镉毒性的分子机制本申请的目的是： i) 评估基因的变化。培养细胞和肾脏中镉暴露引起的表达和染色质乙酰化 (Ac)，以及 HDACi 或 BETi 治疗的潜在救援作用；以及 ii) 测试 HDACi 和 BETi 缓解的能力； Cd 诱导的肾毒性本申请的中心假设是组蛋白 Ac 之间的相互作用。线粒体代谢是哺乳动物细胞中镉毒性的一个关键功能靶点。对于该应用，我们的新颖基础数据表明，镉暴露会导致线粒体功能和组蛋白 Ac 至关重要的是，HDACi 和 BETi 治疗可挽救 Cd 诱导的缺陷。这些发现表明组蛋白 Ac 和细胞活力。线粒体功能是 Cd 的重要功能性细胞靶标。这项工作将在 Cd 的背景下进行。两个具体目标，首先，通过 RNA 测序和染色质分析，发现功能重要的基因和通路。 Cd 靶向并由 HDACi 和 BETi 拯救，将在培养的成纤维细胞中进行鉴定。我们将在小鼠体内评估 HDACi 和 BETi 引起的 Cd 肾毒性。暴露于镉的肾脏和成纤维细胞的基因表达特征，以确定核心基因表达程序驱动 Cd 毒性，特别关注那些由 HDACi 和 BETi 拯救的人。该方法是创新的。 Cd 引起的表观遗传改变与其生物效应之间的机制联系尚未确定最终确定，并使用针对组蛋白 Ac 或表观遗传扰动的小分子更广泛地说，因为此前尚未描述过镉毒性的治疗方法，因此这项工作意义重大。对镉毒性的改进机制治疗的需求尚未得到满足，这些研究可能会确定组蛋白。 Ac 作为 Cd 毒性的新型治疗靶点。