Molecular Effects of Low Level Arsen

低水平接触（1-50 ppb）砷会导致多种毒性作用。新的饮用水砷标准（10 ppb）是基于膀胱癌的发生。砷引起膀胱癌的机制尚不清楚。此外，低水平砷暴露产生膀胱损伤的毒性作用尚未得到充分研究。我们的研究将探讨低水平砷暴露于膀胱组织的机制。永生化人上皮细胞系（UTOtsa）将是主要的模型系统。在初步研究中，UROtsa细胞被证明能够将无机砷生物转化为毒性更大的甲基化代谢物和低水平（1-50 ppb）的砷化学物质 对细胞有细胞毒性。我们的目标是：（1）确定砷在膀胱中生物转化产生亚细胞毒性效应的作用。无机砷的生物转化将被操纵，以确定砷代谢物是最终的毒物。2.）的情况。确定低水平砷暴露于膀胱是否通过蛋白毒性机制产生毒性。本研究将检查砷物种是否通过与关键巯基靶点直接相互作用产生毒性作用。3.）第三章确定低水平砷暴露于膀胱是否通过氧化应激机制产生毒性。活性氧物质的产生和随后的毒性作用将被描述为各种砷化学物质，4。确定低水平砷暴露于膀胱是否影响泛素途径及其毒性 后果砷已被证明可以改变细胞中蛋白质的加工过程。我们的研究表明，低水平的砷会导致泛素化蛋白的积累。我们的研究将描述这种积累，确定是否积累了特定的蛋白质，并确定这些积累的蛋白质对细胞活力的影响。5.）确定砷对膀胱毒性的生物标志物是否来自先前的研究。来自手术患者的膀胱样本将用于砷的体外毒性研究，以确定我们是否看到与细胞相似的效应，以及是否存在潜在的生物标志物（泛素化蛋白质）。总之，这些研究将阐明低水平砷在人类膀胱模型中的毒性作用，并为砷诱导的膀胱损伤提供潜在的生物标志物。

Low-level exposure (1-50 ppb) arsenic causes a multitude of toxic effects. The new drinking water standard for arsenic (10 ppb) is based on the occurrence of bladder cancer. The mechanism(s) by which arsenic produces bladder cancer are unknown. Additionally the toxic effects of low-level arsenic exposure to produce bladder injury have not been adequately examined. Our studies will examine mechanisms of low-level arsenic exposure to bladder tissue. An immortalized human epithelial cell line (UTOtsa) will be the primary model system. In preliminary studies UROtsa cells were shown to be capable of biotransforming inorganic arsenic to more toxic methylated metabolites and low-level (1-50 ppb) arsenic chemical species were cytotoxic to the cells. Our Aims are to: 1.) Determine the role of biotransformation of arsenic in bladder to produce sub-cytotoxic effects. The biotransformation of inorganic arsenic will be manipulated to determine which arsenic metabolite is the ultimate toxicant. 2.) Determine if the low-level arsenic exposure to the bladder is producing toxicity via proteotoxic mechanisms. This study will examine if arsenic species produce toxic effects via direct interaction with critical sulfhydryl targets. 3.) Determine if the low-level arsenic exposure to the bladder produces toxicity via an oxidative stress mechanism. The production of reactive oxygen species and the ensuing toxic effects will be profiled for various arsenic chemical species, 4.) Determine if the low-level arsenic exposure to the bladder is affecting the ubiquitin pathway and its toxic consequences. Arsenic has been shown to alter the processing of proteins in a cell. Our studies show low-level arsenic to cause and an accumulation of ubiquinated proteins. Our studies will characterize this accumulation, identify if specific proteins are accumulated, and determine the impact of these accumulated proteins on cell viability. 5.) Determine if biomarkers of arsenic toxicity to the bladder result from the preceding studies. Bladder samples from surgical patients will be used for in vitro toxicity studies with arsenic to determine if we see similar effects to those seen with the cells and if the potential biomarkers are present (ubiquinated proteins). Overall, these studies will clarify the toxic effects of low-level arsenic in a human bladder model and provide potential biomarkers for arsenic-induced bladder injury.