Persistent transcriptional changes induced by nickel through epigenetic alterations

项目摘要 镍（Ni）化合物是环境毒物，由于其在几种环境中的使用而普遍存在于大气中。 工业过程，以及含镍产品如不锈钢的大量消耗， 电池、医疗器械和医疗植入物。此外，化石燃料的燃烧是镍的主要来源 大气中的污染。接触镍是一个主要的人类健康危害，与许多 包括过敏性接触性皮炎、支气管炎、肺纤维化和肺水肿在内的健康风险。 此外，流行病学研究表明，癌症的发展是镍暴露的主要结果。然而，在这方面， 镍诱导的疾病的分子基础仍然知之甚少。为了更好地理解 镍诱导的疾病的机制，我们研究了镍暴露对人类上皮细胞的影响， 细胞我们的研究表明，镍暴露诱导的基因表达变化持续很长一段时间后，停止镍暴露。 exposure.这导致细胞经历上皮-间充质转化（EMT），并且EMT 表型在暴露终止后持续很长时间。EMT是极化上皮细胞 细胞失去细胞-细胞粘附并获得侵入性和迁移性间质特性。急救队涉嫌 许多与镍暴露相关的疾病，包括哮喘、纤维化、癌症和转移。因此，我们认为， 我们的研究结果表明，镍暴露引起的持续转录变化可能是重要的， 镍暴露相关疾病的病因学。该补助金的首要目标是了解 机制，驱动镍暴露引起的长期转录变化。我们的初步结果表明 镍暴露破坏了由组蛋白修饰H3 K27 me 3和锌介导的染色质调节， 指状蛋白，CTCF。根据我们的初步结果，我们假设镍暴露增加 通过H3 K27 me 3损失的染色质可及性，引起基因上调。CTCF绑定新的 可接近的染色质，并防止在Ni暴露终止后H3 K27 me 3重新建立， 从而持续改变基因表达。在目的1中，我们将研究H3 K27 me 3-损失在Ni-中的作用。 在人肺上皮细胞中诱导持续的基因表达改变。在目标2中，我们将研究 镍诱导的持续性染色质改变的机制是通过敲低CTCF和破坏 使用CRISPR/Cas9系统检查CTCF结合位点的丧失是否可以逆转Ni诱导的 持续的转录变化。在目标3中，我们将检查镍诱导的持续性 通过研究小鼠中Ni暴露的细胞的肿瘤生成潜力来观察转录变化。整体 我们的研究的影响将是确定长期转录变化的机制 揭示其致病的分子基础，并将对人类健康产生重大影响。 健康影响。

Project Summary Nickel (Ni) compounds are environmental toxicants, prevalent in the atmosphere due to their use in several industrial processes, as well as extensive consumption of Ni containing products such as stainless steel, batteries, medical devices and medical implants. In addition, combustion of fossil fuels is a major source of Ni contamination in the atmosphere. Exposure to Ni is a major human health hazard, associated with a multitude of health risks including allergic contact dermatitis, bronchitis, pulmonary fibrosis, and pulmonary edema. Moreover, epidemiological studies indicate cancer development as a major outcome of Ni exposure. However, the molecular basis of Ni-induced diseases remains poorly understood. To better understand the molecular mechanisms underlying Ni-induced diseases, we investigated the effects of Ni-exposure on human epithelial cells. Our studies show that Ni-exposure-induced gene expression changes persist long after the cessation of exposure. This resulted in the cells undergoing epithelial-mesenchymal transition (EMT), and the EMT phenotype continued long after the termination of exposure. EMT is the process in which polarized epithelial cells lose cell-cell adhesion and acquire invasive and migratory mesenchymal properties. EMT is implicated in a number of diseases associated with Ni-exposure including asthma, fibrosis, cancer and metastasis. Therefore, our results suggest that persistent transcriptional changes caused by Ni exposure are likely important in the etiology of Ni-exposure associated diseases. The overarching goal of this grant is to understand the mechanisms that drive long-term transcriptional changes caused by Ni exposure. Our preliminary results suggest that Ni-exposure disrupts chromatin regulation mediated by the histone modification, H3K27me3 and the zinc finger protein, CTCF. Based on our preliminary results, we hypothesize that Ni-exposure increases chromatin accessibility through H3K27me3 loss, causing gene upregulation. CTCF binds the newly accessible chromatin and prevents H3K27me3 re-establishment after termination of Ni-exposure, thereby persistently altering gene expression. In Aim 1, we will investigate the role of H3K27me3-loss in Ni- induced persistent gene expression alterations in human lung epithelial cells. In Aim 2, we will investigate the mechanisms underlying Ni-induced persistent chromatin alterations by knocking-down CTCF and by disrupting CTCF binding sites using CRISPR/Cas9 system to examine if loss of CTCF binding could reverse Ni-induced persistent transcriptional changes. In Aim 3, we will examine the functional outcome of Ni-induced persistent transcriptional changes by investigating the tumor generating potential of Ni-exposed cells in in mice. The overall impact of our study will be the identification of the mechanisms underlying long-term transcriptional changes caused by nickel exposure, which will reveal the molecular basis of its pathogenicity, and will have major human health implications.