Cytoplasmic-nuclear redox signaling: Disruption by dietary cadmium levels

描述(申请人提供)：细胞质-核氧化还原信号：饮食镉水平的干扰我们最近对半胱氨酸蛋白质组氧化还原依赖性的研究表明，美国饮食中存在的镉(Cd)水平会刺激硫氧还蛋白-1(Trx1)移位到细胞核中，并通过核转录因子-κB增强炎症信号。这些水平低于公认的毒性水平，因此必须谨慎对待结果。尽管如此，这一发现仍具有重大的健康影响，因为炎症导致了许多慢性病。流行病学研究将低水平的环境镉与肺癌、肺气肿和其他肺部疾病以及心力衰竭和中风、骨质疏松症、贫血、生殖衰竭和其他癌症的风险联系起来；对低水平镉的机械理解不足和混杂的变量限制了在风险评估或政策决策中使用这些研究结果。这一基础科学项目的目的是通过检验这一中心假设来提高对机制的理解，该中心假设饮食中的镉水平通过破坏与肌动蛋白细胞骨架控制和核功能相关的氧化还原蛋白质组来增强炎症性肺病。该项目基于对氧化还原敏感的细胞质-核信号的最新进展，我们关于低剂量镉的氧化还原蛋白质组学的最新数据，以及关于镉的生物效应的大量文献。我们将使用分子和细胞方法，结合基于质谱学的氧化还原蛋白质组学，在体外和体内肺部疾病模型中研究CD对细胞质-核氧化还原系统的破坏。我们特别关注肺，因为氧化还原敏感的转录在肺功能中的中心作用，特别是炎症和纤维化，并且因为饮食中的镉效应可能会因镉的吸入而加剧。目的1研究小剂量镉对氧化还原蛋白质组的作用机制。我们将检验这一假设，即CD对肌动蛋白细胞骨架蛋白的影响导致Trx1移位到细胞核中，并刺激调节炎症和纤维化反应的转录因子的活性。目的2确定小剂量镉是否通过影响核氧化还原信号而增强肝纤维化和炎症前机制。研究将使用博莱霉素和H1N1流感病毒分别用于纤溶和炎症的肺部疾病体外细胞模型。目的3使用与目的2类似的小鼠肺部疾病模型，以测试低剂量镉是否通过影响体内的核氧化还原控制系统和转录因子活性来增强炎症和纤维化信号；目的还包括对人肺样本的研究，以允许 模型系统对人肺Cd含量的直接校准。这些结果将表明，美国人饮食中发现的水平的镉暴露是否会对炎症和纤维化的细胞质-核细胞信号机制产生不利影响。如果是这样的话，全球蛋白质组和转录组数据，以及校准的镉依赖的炎症和纤维化标志物，将为有针对性地评估人类饮食中镉的健康风险提供必要的数据。

DESCRIPTION (provided by applicant): Cytoplasmic-nuclear redox signaling: Disruption by dietary cadmium levels Our recent research on the redox dependence of the cysteine proteome shows that levels of cadmium (Cd) present in the American diet stimulate translocation of thioredoxin-1 (Trx1) into cell nuclei and potentiate inflammatory signaling by NF-κB. These levels are below recognized toxic levels and so the results must be approached with caution. None-the-less, the finding has substantial health implications because inflammation contributes to many chronic diseases. Epidemiologic studies associate low-level environmental Cd to the risk of lung cancer, emphysema and other lung diseases, as well as heart failure and stroke, osteoporosis, anemia, reproductive failure and other cancers; poor mechanistic understanding of low-level Cd and confounding variables limit use of these findings in risk assessment or policy decisions. The purpose of this basic science project is to improve mechanistic understanding by testing the central hypothesis that dietary Cd levels potentiate inflammatory lung disease through disruption of the redox proteome associated with actin cytoskeleton control and nuclear function. The project is based upon recent advances in redox-sensitive cytoplasmic-nuclear signaling, our recent data on redox proteomics of low-dose Cd and an extensive literature on biologic effects of Cd. We will use molecular and cellular methods along with mass spectrometry-based redox proteomics to study Cd disruption of cytoplasmic-nuclear redox systems in in vitro and in vivo lung disease models. We specifically focus on the lung because of the central role of redox-sensitive transcription in lung function, especially inflammation and fibrosis, and because dietary Cd effects can be exacerbated by Cd inhalation. Aim 1 is to investigate mechanisms of low-dose Cd on the redox proteome. We will test the hypothesis that Cd effect on actin cytoskeleton proteins causes translocation of Trx1 into nuclei and stimulates activity of transcription factors regulating inflammation and fibrotic responses. Aim 2 is to determine whether low-dose Cd potentiates profibrosis and proinflammation mechanisms by affecting nuclear redox signaling. Studies will use in vitro cell models of pulmonary diseases using bleomycin and H1N1 influenza virus for profibroitc and inflammatory agents, respectively. Aim 3 uses mouse models of pulmonary disease paralleling Aim 2, to test whether low-dose Cd potentiates inflammatory and fibrotic signaling by affecting nuclear redox control systems and transcription factor activity in vivo; the Aim also includes studies of human lung samples to allow direct calibration of model systems to human lung Cd contents. These results will show whether Cd exposures at levels found in the American diet adversely impacts the mechanisms of cytoplasmic-nuclear cell signaling of inflammation and fibrosis. If so, the global proteomic and transcriptomic data, along with calibrated Cd-dependence of markers of inflammation and fibrosis, will provide essential data for targeted evaluation of dietary Cd health risks in humans.