Cytoplasmic-nuclear redox signaling: Disruption by dietary cadmium levels

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，美国饮食中的镉（Cd）水平刺激硫氧还蛋白-1 （Trx1）转运到细胞核，并通过NF-κB增强炎症信号传导。这些水平低于公认的有毒水平，因此必须谨慎对待结果。尽管如此，这一发现具有重大的健康意义，因为炎症会导致许多慢性疾病。流行病学研究将低水平环境中的镉与肺癌、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、生殖功能衰竭和其他癌症的风险联系起来；对低水平Cd的机制理解不足和混杂变量限制了这些发现在风险评估或政策决策中的应用。本基础科学项目的目的是通过验证膳食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而加剧炎性肺病的中心假设，从而提高对机制的理解。该项目基于氧化还原敏感细胞质-核信号的最新进展，我们最近关于低剂量Cd氧化还原蛋白质组学的数据以及关于Cd生物效应的大量文献。我们将使用分子和细胞方法以及基于质谱的氧化还原蛋白质组学来研究体外和体内肺部疾病模型中Cd对细胞质-核氧化还原系统的破坏。我们特别关注肺，因为氧化还原敏感转录在肺功能中的核心作用，特别是炎症和纤维化，因为饮食中的Cd效应可以通过吸入Cd而加剧。目的1：探讨低剂量镉对氧化还原蛋白质组的作用机制。我们将验证Cd对肌动蛋白细胞骨架蛋白的影响导致Trx1易位进入细胞核并刺激调节炎症和纤维化反应的转录因子活性的假设。目的2是确定低剂量镉是否通过影响核氧化还原信号来增强促纤维化和促炎症机制。研究将使用体外肺疾病细胞模型，分别使用博来霉素和H1N1流感病毒作为促纤维化剂和炎症剂。Aim 3使用与Aim 2相似的肺部疾病小鼠模型，测试低剂量Cd是否通过影响体内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；Aim还包括对人类肺样本的研究

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.