Elucidating epigenetic mechanisms of cellular cadmium toxicity

阐明细胞镉毒性的表观遗传机制

• 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
• 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

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.

摘要 镉（Cd）是一种广泛的环境污染物，影响着全世界数百万人。CD 人类接触镉最常见的方式是通过镉的许多工业应用，或 被污染的食物由于其极长的生物半衰期，镉在组织中持续数十年，主要是 肝脏和肾脏镉产生许多有害影响，包括骨骼，生殖， 神经发育和肺毒性以及致癌作用。肾脏是镉的主要靶器官 毒性，特别是近端肾小管上皮细胞，损伤会阻碍肾小管重吸收。尽管 人类接触镉有许多后遗症，镉毒性的特定分子机制是 了解甚少，也没有具体的治疗存在，以减轻镉暴露的影响。通过无偏见的高- 通过筛选，我们发现了一种以前未知的能力，多种化学上不同的组蛋白 去乙酰化酶抑制剂（HDACi）和溴结构域和末端外基序抑制剂（BETi）以拯救急性 细胞镉毒性这些研究的长期目标是阐明细胞的新方面， 镉毒性的分子机制。本申请的目的是：i）评估基因的变化， 表达和染色质乙酰化（Ac）发生在培养的细胞和肾脏中， 以及它们通过HDACi或BETi治疗的潜在拯救;以及ii）测试HDACi和BETi减轻 镉致肾毒性。本申请的中心假设是组蛋白Ac 线粒体代谢是哺乳动物细胞中镉毒性的关键功能靶点。的理由 对于这种应用，我们的新的基础数据表明，镉暴露诱导减少， 线粒体功能和组蛋白Ac。至关重要的是，HDACi和BETi治疗挽救了Cd诱导的缺陷， 线粒体呼吸、代谢物水平和细胞活力。这些发现表明组蛋白Ac和 线粒体功能是镉的重要功能性细胞靶点。这项工作将在以下背景下进行： 两个具体目标。首先，通过RNA-seq和染色质分析， 被Cd靶向并被HDACi和BETi拯救的细胞将在培养的成纤维细胞中鉴定。第二，救援 将在小鼠体内评价HDACi和BETi引起的Cd诱导的肾毒性。我们将比较 镉暴露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 驱动镉毒性，特别是集中在那些拯救HDACi和BETi。该方法具有创新性， 镉诱导的表观遗传改变与其生物学效应之间的机制联系尚未得到证实， 结论性地建立，以及使用针对组蛋白Ac或表观遗传扰动的小分子 更一般地说，对于Cd毒性的处理以前没有描述过。这项工作意义重大，因为 对于Cd毒性的改进的机理治疗存在未满足的需求。这些研究可能建立组蛋白 Ac作为镉毒性的新治疗靶点。