Stress response, p97, and Nrf2 in arsenic-mediated toxicity

砷介导的毒性中的应激反应、p97 和 Nrf2

• 批准号: 8957408
• 负责人: Eli Chapman
• 金额: $ 32.95万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-02-01 至 2018-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8957408
• 关键词: ATP Hydrolysis; ATP phosphohydrolase; Air; Amaze; Antioxidants; Arsenic; Arsenicals; Arsenites; Autophagocytosis; Autophagosome; Binding; Biochemical; Biochemistry; Biological; Bladder; Carcinogens; Cardiovascular system; Cell Cycle; Cell Survival; Cell physiology; Cells; Cellular Stress Response; Chronic; Complex; Coupled; Developing Countries; Diabetes Mellitus; Disease; Elements; Endoplasmic Reticulum; Enzymatic Biochemistry; Epidemiologic Studies; Exposure to; Foot Diseases; Frontotemporal Dementia; Genes; Growth; Health; Heat shock proteins; Heat-Shock Response; Homeostasis; Human; Impairment; In Vitro; Inclusion Body Myopathy with Early-Onset Paget Disease; Lead; Link; Lysosomes; Maintenance; Malignant Neoplasms; Malignant neoplasm of lung; Measures; Mediating; Membrane Proteins; Metabolic Diseases; Modeling; Molecular; Mus; Names; Oxidation-Reduction; Oxidative Stress; Oxides; Pathology; Pathway interactions; Proteins; Quality Control; Recombinants; Regulation; Reporting; Research; Response Elements; Risk; Series; Skin; Societies; Soil; Source; Specificity; System; Toxic effect; Transgenes; Transgenic Mice; Ubiquitin; Up-Regulation; Variant; Vascular Diseases; Work; autosomal dominant mutation; biological adaptation to stress; contaminated drinking water; contaminated water; in vivo; macromolecular assembly; metaplastic cell transformation; mouse model; multicatalytic endopeptidase complex; mutant; p97 ATPase; pollutant; prevent; programs; reconstitution; response; stress protein; transcription factor; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Arsenic and its arsenical derivatives are estimated to effect greater than 200 million people worldwide. Exposure to arsenicals comes from a number of sources such as contaminated drinking water, soil or as an airborne pollutant. Various epidemiological studies have linked chronic arsenic exposure to a number of disease states including cancer of the lungs, bladder, or skin; metabolic diseases such as diabetes; cardiovascular and other vascular diseases; and skin problems such as 'black foot disease'. In addition to the epidemiological studies there has been a great deal of effort to understand the mechanisms of pathology, but to date many questions along these lines remain obfuscated. Part of the problem with understanding arsenic toxicity is the sheer number of cellular systems that arsenic alters. For instance arsenic leads to oxidative stress, compromise of protein quality control, heat-shock response, and cell-cycle alterations to name a few. Work from our lab has identified a crucial link in the effects of arsenic on cells. Chronic treatment with low levels of arsenite (one of the oxides of arsenic) leads to a compromise of autophagy, a major protein quality control pathway. This breach comes at the step of autophagosome/lysosome fusion, leading to a build-up of autophagosomes and high levels of the autophagy specificity factor, p62. Critically, p62 contains a recognition element for Keap1, which is a substrate recognition factor in the Cul3-Keap1-Rbx1 E3 ubiquitin ligase complex. This E3 complex normally maintains a low level of the oxidative stress responsive transcription factor, Nrf2. In the presence of excess p62, Keap1 is occupied, allowing for constitutive, high level expression of Nrf2 and subsequent activation of antioxidant response element regulated genes. This high-level expression confers a growth advantage on the cells and can lead to diseases such as cancer. Despite these mechanistic leaps, it remains the mechanism by which arsenite interferes with autophagy is unknown. In the present research program we propose the hypothesis that arsenicals interfere with the AAA+ protein quality control machine, p97. This provides a critical link between arsenic and autophagy as well as other protein quality control mechanisms. To probe the detailed mechanistic underpinnings of this arsenic-mediated breach we will use an array of detailed mechanistic enzymology studies, coupled with cellular biochemistry, and in vivo studies. These efforts will be greatly aided by the multi-PI team we have assembled.

描述（由申请人提供）：据估计，砷及其砷衍生物影响全球2亿多人。砷的暴露来自许多来源，如受污染的饮用水、土壤或空气污染物。各种流行病学研究表明，慢性砷暴露与多种疾病有关，包括肺癌、膀胱癌或皮肤癌;糖尿病等代谢性疾病;心血管和其他血管疾病;以及“黑脚病”等皮肤问题。除了流行病学研究，人们还做了大量的努力来了解病理学的机制，但迄今为止，这些方面沿着许多问题仍然令人困惑。理解砷毒性的部分问题是砷改变的细胞系统的绝对数量。例如，砷会导致氧化应激、蛋白质质量控制的妥协、热休克反应和细胞周期的改变等等。我们实验室的工作已经确定了砷对细胞影响的关键环节。长期低水平的亚砷酸盐（砷的氧化物之一）治疗导致自噬的妥协，一个主要的蛋白质质量控制途径。这种破坏发生在自噬体/溶酶体融合的步骤中，导致自噬体的建立和高水平的自噬特异性因子p62。重要的是，p62含有Keap 1的识别元件，Keap 1是Cul 3-Keap 1-Rbx 1 E3泛素连接酶复合物中的底物识别因子。这种E3复合物通常维持低水平的氧化应激反应转录因子Nrf 2。在存在过量p62的情况下，Keap 1被占据，从而允许Nrf 2组成性高水平表达，并随后激活抗氧化反应元件调节基因。这种高水平表达赋予细胞生长优势，并可能导致癌症等疾病。尽管有这些机制上的飞跃，但亚砷酸盐干扰自噬的机制仍然是未知的。在目前的研究计划中，我们提出了砷干扰AAA+蛋白质质量控制机器p97的假设。这提供了砷和自噬以及其他蛋白质质量控制机制之间的关键联系。为了探索这种砷介导的破坏的详细机制基础，我们将使用一系列详细的机制酶学研究，再加上细胞生物化学和体内研究。这些努力将得到我们组建的多PI团队的极大帮助。