Novel markers of exposure and pathways of response to Chromium

铬暴露和反应途径的新标记

基本信息

批准号：
10666906
负责人：
Bernardo Lemos
金额：
$ 20.75万
依托单位：
UNIVERSITY OF ARIZONA
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-08-09 至 2024-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10666906
关键词：
Address Affect Animal Model Architecture Biogenesis Biology Carcinogens Cell Cycle Progression Cell Nucleolus Cell Nucleus Cell model Cell physiology Cells Cellular biology Chemicals China Chromatin Chromium Chromosome Segregation Clustered Regularly Interspaced Short Palindromic Repeats Complex DNA Damage DNA Repair DNA amplification DNA copy number Data Dose Drosophila genus Elements Epigenetic Process Epithelial Cells Exposure to Gene Dosage Gene Expression Gene Silencing Genes Genetic Genetic Determinism Genetic Transcription Genome Genome Components Genomics Germany Health Heterochromatin Human Induced Mutation Information Resources Injury Investigation Knock-out Light Lung Malignant Neoplasms Mammalian Cell Maps Mediating Medical Metal exposure Metals Mission Mus NCI Center for Cancer Research National Institute of Environmental Health Sciences Nuclear Occupational Oncogenes Organelles Pathway interactions Play Population Process Public Health RNA Reactive Oxygen Species Recovery Research Resolution Rest Ribosomal DNA Ribosomal RNA Ribosomes Role Seminal Site Stress Superoxide Dismutase TP53 gene Techniques Technology Testing Time Tissues Toxic Environmental Substances Toxic effect Toxicology United States National Institutes of Health Variant Work carcinogenesis chromium hexavalent ion directed attention drinking water expectation exposure pathway functional genomics gain of function mutation gene interaction genetic analysis genome-wide human disease individual response loss of function novel novel marker nucleolar organizing region recruit response skills

项目摘要

Abstract Cr(VI) is a human carcinogen of significant public health concern, and a substantial exposure in a number of occupational settings. Cr(VI) induces mutations, changes in gene copy number, and exposure has been associated with humans cancers in exposed populations and animal models. Our novel preliminary data demonstrate that Cr(VI) exposure causes amplification in ribosomal DNA (rDNA) copy number and changes in the nucleolus (the crudely understood nuclear organelle that is the site of ribosomal RNA (rRNA) transcription, and integration of myriad cellular functions). A crucial element of nucleolar function is rDNA copy number (rDNA CN). rDNA CN modulates (i) epigenetic states across the genome, (ii) DNA damage responses, (iii) cell cycle progression, (iv) chromosome segregation, and (v) global genetic stability. Furthermore, disruption of rDNA arrays, ribosome biogenesis, and the nucleolus are central to carcinogenesis. Our central medical hypothesis is that Cr-induced changes in rDNA CN are responsible for Cr-induced carcinogenesis. Our central basic hypothesis is that rDNA arrays are not fixed, but rather a genetically dynamic component of the nuclear genome with copy number that is modulated by Cr exposure. Our proposal examines rDNA changes upon Cr(VI) exposure to reveal a novel pathway of Cr toxicity with medical and basic relevance. Key elements are a careful investigation of the toxicology of Cr-induced-rDNA-amplification (Cr-i-rDNA-a), hypotheses-driven functional genomic analysis the rDNA and the nucleolus upon Cr(VI) exposure, and extensive genetic analyses of Cr-i-rDNA-a using a powerful model organism. Our first aim will investigate the toxicology of Chromium- induced-rDNA-amplification (Cr-i-rDNA-a) in a human lung epithelial cell model. We will determine dose- responses of Cr-i-rDNA-a, map amplification boundaries in Cr-i-rDNA-a, examine temporal profiles and recovery from Cr(VI) exposure, and examine whether Chromium-induced CN changes are responsible for Cr- induced carcinogenesis. Our second aim investigates the functional genomics of Cr-induced nucleolar stress and Cr induced transformation in a human lung epithelial cell model. Examining genome-wide responses to Cr exposure is critical to understand how Cr induces rDNA amplification, nuclelar stress, and carcinogenesis. Our third aim addresses the genetic determinants of Chromium-rDNA interactions. We will examine Cr-i-rDNA-a in specific cells, quantify the extent of copy number change, isolate the affected tissues, and use high-throughput techniques to characterize the changes. Our efforts will shed light on Cr-rDNA interactions, with research that is directly relevant to the human health mission of the NIH. The manifold effects of rDNA CN indicate that perturbing this central regulator with Cr will have profound consequences to cellular function. We anticipate that determinants of complex human diseases with strong environmental components such as cancer will ultimately be traced to environmentally triggered variation in rDNA segments of the genome.

抽象的 Cr(VI) 是一种具有重大公共卫生问题的人类致癌物，在许多环境中大量暴露职业设置。 Cr(VI) 会诱发突变、基因拷贝数的变化，并且暴露已被证实与暴露人群和动物模型中的人类癌症有关。我们新颖的初步数据证明 Cr(VI) 暴露会导致核糖体 DNA (rDNA) 拷贝数扩增以及核仁（粗略理解的核细胞器，是核糖体 RNA (rRNA) 转录的位点，以及无数细胞功能的整合）。核仁功能的一个关键因素是 rDNA 拷贝数（rDNA CN）。 rDNA CN 调节 (i) 整个基因组的表观遗传状态，(ii) DNA 损伤反应，(iii) 细胞周期进展，（iv）染色体分离，以及（v）整体遗传稳定性。此外，破坏 rDNA 阵列、核糖体生物发生和核仁是癌发生的核心。我们中央医疗假设是 Cr 诱导的 rDNA CN 变化是 Cr 诱导癌发生的原因。我们的中央基本假设是 rDNA 阵列不是固定的，而是核的遗传动态组成部分基因组的拷贝数受 Cr 暴露的调节。我们的提案检查 rDNA 变化 Cr(VI) 暴露揭示了具有医学和基础相关性的 Cr 毒性的新途径。关键要素是仔细研究 Cr 诱导的 rDNA 扩增 (Cr-i-rDNA-a) 的毒理学，假设驱动对 Cr(VI) 暴露后的 rDNA 和核仁进行功能基因组分析，以及广泛的遗传分析使用强大的模型生物体进行 Cr-i-rDNA-a 的研究。我们的首要目标是研究铬的毒理学- 人肺上皮细胞模型中的诱导 rDNA 扩增 (Cr-i-rDNA-a)。我们将确定剂量- Cr-i-rDNA-a 的响应，绘制 Cr-i-rDNA-a 中的扩增边界，检查时间曲线并从 Cr(VI) 暴露中恢复，并检查铬引起的 CN 变化是否是 Cr- 的原因诱发癌变。我们的第二个目标是研究 Cr 诱导的核仁应激的功能基因组学和 Cr 在人肺上皮细胞模型中诱导转化。检查全基因组对 Cr 的反应接触 Cr 对于了解 Cr 如何诱导 rDNA 扩增、核应激和致癌作用至关重要。我们的第三个目标解决铬-rDNA 相互作用的遗传决定因素。我们将检查 Cr-i-rDNA-a 特定细胞，量化拷贝数变化的程度，分离受影响的组织，并使用高通量表征变化的技术。我们的研究将揭示 Cr-rDNA 相互作用与 NIH 的人类健康使命直接相关。 rDNA CN 的多重效应表明用 Cr 扰乱这个中央调节器将对细胞功能产生深远的影响。我们预计具有强烈环境因素的复杂人类疾病（例如癌症）的决定因素将最终可以追溯到环境引发的基因组 rDNA 片段的变异。