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.

抽象的 镉（CD）是一种广泛的环境污染物，影响了全球数百万个人。光盘 人类的暴露最常通过CD的许多工业应用发生，或者消费 被污染的食物。由于其非常延长的生物半衰期，CD在组织中持续数十年，主要 CD导出了许多有害影响，包括骨骼，复制性， 神经发育，肺毒性以及癌变。孩子们是CD的主要目标 毒性，尤其是近端管状上皮细胞，损伤会阻碍肾小管重吸收。尽管 与人类中CD暴露有关的许多后遗症，CD毒性的特定分子机制是 知之甚少，没有特定的疗法来减轻CD暴露的影响。通过公正的高级 吞吐量筛选，我们确定了多个化学上不同组蛋白的先前未知能力 脱乙酰基酶抑制剂（HDACI）和溴结构域和末端基序抑制剂（BETI）以营救急性 细胞CD毒性。这些研究的长期目标是阐明细胞的新方面 CD毒性的分子机制。该应用程序的目标是：i）评估基因的变化 在培养细胞和肾脏中响应CD暴露而发生的表达和染色质乙酰化（AC）， 以及他们通过HDACI或BETI治疗的潜在营救； ii）测试HDACI和BETI减轻的能力 CD诱导的肾毒性。该应用的中心假设是Hisstone AC之间的相互作用 线粒体代谢代表了哺乳动物细胞中CD毒性的关键功能靶标。理由 对于此应用，我们的新颖基础数据表明CD暴露在 线粒体功能和组蛋白AC。至关重要的是，用HDACI和BETI救援CD诱导的缺陷进行治疗 线粒体呼吸，代谢物水平和细胞活力。这些发现意味着Hisstone AC和 线粒体功能是CD的重要功能细胞靶标。这项工作将在 两个具体的目标。首先，通过RNA-Seq和染色质分析，功能上重要的基因和途径 由CD的靶向，并由HDACI和BETI救出，将在培养的成纤维细胞中鉴定。第二，救援 HDACI和BETI在小鼠的体内将评估CD诱导的肾毒性。我们将比较 CD暴露肾脏和成纤维细胞的基因表达特征，以识别核心基因表达程序 驾驶CD毒性，尤其是专注于HDACI和BETI营救的毒性。这种方法是创新的，在 CD诱导的表观遗传改变及其生物学作用之间的机械联系尚未 最终确定了针对组蛋白AC或表观遗传扰动的小分子的使用 以前尚未描述为CD毒性的治疗方法。这项工作很重要，因为 需要改善CD毒性的机制治疗的需求。这些研究可能建立组蛋白 AC是CD毒性的新型治疗靶标。