CADMIUM, ZINC, METALLOTHIONEIN AND KIDNEY TOXICITY

镉、锌、金属硫蛋白和肾脏毒性

• 批准号: 2153515
• 负责人: DAVID Harold PETERING
• 金额: $ 22.96万
• 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/2153515
• 关键词: Xenopus; alternatives to animals in research; 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.

在人类毒理学中，接触镉是一个长期存在的问题。一个 主要的作用大小是肾脏，镉会产生一系列 管状溶质的肾小管吸收缺陷，包括葡萄糖，氨基酸， 和磷酸盐。大量研究将金属硫蛋白（MT）视为关键 CD2+的细胞形成和毒性中的蛋白质以及 锌和铜的代谢。 金属簇的生物无机研究 在MT中，为理解其在细胞中的某些行为提供了基础。 然而，肾脏毒性的分子位点既不 金属硫蛋白在亚急性CD毒性中的详细功能作用 和必需的金属代谢是充分理解的。在这种情况下，这个 应用程序阐明了一组集成的假设和特定目的。 据认为，金属硫蛋白的两个结构结构允许 蛋白质在细胞内Zn2+分布中同时起作用，并且 在CD2+隔离中。这个想法将在鼠标肾小管中进行测试 细胞，使用新定义的CD2+缺陷来引起特定的抑制作用 Na+ - 葡萄糖共转移，没有广义细胞毒性。它也会 在金属硫蛋白的模型研究中探索以了解 化学上蛋白质的细胞特性。主要问题 解决包括（1）受CD2+影响的细胞途径是什么 导致抑制Na+ - 葡萄糖共传输？ （2）什么是细胞 CD2+与抑制Na+葡萄糖的关系 共同运输？ （3）是金属硫蛋白在锌代谢中的作用 受镉结合的扰动？ （4）什么是什么 金属硫蛋白控制其在细胞锌和镉中的反应性 代谢和物种形成？该提案涉及三名高级调查员 具有互补的专业知识，SSB在文化和研究中 肾皮质细胞的转运特性，生物无机中的CFS 金属药物和蛋白质的化学性质和细胞中的DHP 必需金属和有毒金属的形态以及特性 金属蛋白。他们将采用radiotracers遵循 CD2+在Na+ - 葡萄糖共传输，转运蛋白mRNA合成，转运蛋白 与CD2+C分布有关的生物合成和降解。重点是 与Zn-MT蛋白的相互作用和细胞内分布 锌以及MT的感应系统。相关的动力学实验 MT及其孤立的α-和β-将进行模型 细胞中镉形成和定位的过程。