CADMIUM, ZINC, METALLOTHIONEIN AND KIDNEY TOXICITY

镉、锌、金属硫蛋白和肾脏毒性

• 批准号: 3251851
• 负责人: DAVID Harold PETERING
• 金额: $ 19.56万
• 依托单位: UNIVERSITY OF WISCONSIN MILWAUKEE
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-01 至 1995-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3251851
• 关键词: Xenopus; biological models; cadmium; chemical binding; chemical structure function; chemical substitution; cytotoxicity; gel filtration chromatography; high performance liquid chromatography; laboratory mouse; metal metabolism; metal poisoning; metallothionein; nuclear magnetic resonance spectroscopy; radiotracer; renal cortex; renal toxin; renal tubular transport; spectrometry; tissue /cell culture; toxicant interaction; zinc

Exposure to cadmium is a long standing problem in human toxicology. A principal size of action is the kidney, where cadmium produces a series of defects in tubular reabsorption of solutes, including glucose, amino acids, and phosphate. Numerous studies identify metallothionein (MT) as a key protein in the cellular speciation and toxicity of Cd2+ as well as in the metabolism of zinc and copper. Bioinorganic research on the metal clusters in MT provide a basis for understanding some of its behavior in cells. Nevertheless, neither the molecular site(s) of renal cadmium toxicity nor the detailed functional roles of metallothionein in subacute Cd toxicity and essential metal metabolism are well understood. In this context, this application sets forth an integrated set of hypotheses and specific aims. It is thought that the two domain structure of metallothionein permits the protein to function simultaneously in intracellular Zn2+ distribution and in Cd2+ sequestration. This idea will be tested in mouse renal tubule cells, using the newly defined defect of Cd2+ to cause specific inhibition of Na+-glucose co-transport without generalized cell toxicity. It will also be explored in model studies on metallothionein in order to understand chemically the cellular properties of the protein. Major questions to be addressed include (1) What are the cellular pathways affected by Cd2+ which lead to inhibition of Na+-glucose co-transport? (2) What is the cellular speciation of Cd2+ in relationship to inhibition of Na+-glucose co-transport? (3) Is the role of metallothionein in zinc metabolism perturbed by cadmium-binding? (4) What is the underlying chemistry of metallothionein that governs its reactivity in cellular zinc and cadmium metabolism and speciation? The proposal involves three senior investigators with complementary expertise, SSB in the culture and examination of the transport properties of kidney cortical cells, CFS in the bioinorganic chemistry of metallo-drugs and -proteins, and DHP in the cellular speciation of essential and toxic metals and the properties of metalloproteins. They will employ radiotracers to follow the effects of Cd2+ on Na+-glucose co-transport, transporter mRNA synthesis, transporter biosynthesis and degradation in relation to Cd2+c distribution. A focus is on its interaction with Zn-MT protein and intracellular distribution of zinc as well as the induction system for MT. Related kinetic experiments on MT and its isolated alpha- and beta-domains will be carried out to model the process of cadmium speciation and localization in cells.

镉暴露是人类毒理学中一个长期存在的问题。一个 作用的主要大小是肾脏，在那里镉产生一系列的 管状重吸收溶质的缺陷，包括葡萄糖，氨基酸， 和磷酸盐。大量研究发现金属硫蛋白(MT)是关键 Cd~(2+)的细胞形态和毒性以及细胞内的蛋白质 锌和铜的代谢。金属簇合物的生物无机研究 为了解其在细胞中的某些行为提供了基础。 然而，无论是肾镉毒性的分子位点(S)还是 金属硫蛋白在亚急性镉中毒中的详细功能 和必需的金属代谢是很好的理解。在这方面，这一点 申请书提出了一套完整的假设和具体目标。 人们认为，金属硫蛋白的两个结构域结构允许 蛋白质在细胞内锌离子分布和细胞内锌离子分布中同时发挥作用 在Cd~(2+)封存中。这一想法将在小鼠肾小管中进行测试 细胞，利用新定义的CD2+缺陷引起特异性抑制 无普遍细胞毒性的Na+-葡萄糖共转运。它还将 在金属硫蛋白的模型研究中进行探索以了解 从化学上讲，蛋白质的细胞性质。有待解决的主要问题 涉及的内容包括(1)哪些细胞通路受CD2+的影响 导致钠-葡萄糖共转运受抑？(2)什么是细胞 Cd~(2+)形态与钠-葡萄糖抑制的关系 共转运？(3)金属硫蛋白在锌代谢中的作用 对镉的结合感到不安？(4)潜在的化学成分是什么 金属硫蛋白控制其在细胞锌和镉中的反应 新陈代谢和物种形成？该提案涉及三名高级调查人员 在文化和考试方面，SSB拥有互补的专业知识 肾皮质细胞在生物无机物中的转运特性 金属药物和蛋白质的化学，以及细胞中的DHP 必需金属和有毒金属的形态及其性质 金属蛋白。他们将使用放射性示踪剂来跟踪 Cd~(2+)对Na~+-葡萄糖共转运、转运体mRNA合成、转运体的影响 生物合成和降解与Cd~(2+)分布的关系。一个焦点是 其与锌-MT蛋白的相互作用及其在细胞内的分布 锌以及MT的诱导系统。相关的动力学实验 MT及其分离的α和β结构域将被用于建模 镉在细胞中的形态和定位过程。