CADMIUM, ZINC, METALLOTHIONEIN AND KIDNEY CYTOTOXICITY

镉、锌、金属硫蛋白和肾细胞毒性

• 批准号: 3251848
• 负责人: DAVID Harold PETERING
• 金额: $ 20.08万
• 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/3251848
• 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长期存在的问题。一个 镉的主要作用部位是肾脏，镉在肾脏中产生一系列 肾小管重吸收溶质的缺陷，包括葡萄糖、氨基酸、 和磷酸盐。大量研究将金属硫蛋白 (MT) 确定为关键 Cd2+ 的细胞形态和毒性以及 锌和铜的代谢。 金属团簇的生物无机研究 MT 的研究为理解其在细胞中的一些行为提供了基础。 然而，肾镉毒性的分子位点和 金属硫蛋白在亚急性镉毒性中的详细功能作用 和必需金属代谢已众所周知。在此背景下，这 应用提出了一套综合的假设和具体目标。 据认为，金属硫蛋白的两个结构域结构允许 蛋白质在细胞内 Zn2+ 分布中同时发挥作用 Cd2+ 封存。这个想法将在小鼠肾小管中进行测试 细胞，利用新定义的 Cd2+ 缺陷来引起特异性抑制 Na+-葡萄糖共转运，没有普遍的细胞毒性。它还将 在金属硫蛋白的模型研究中进行探索，以便了解 蛋白质的化学性质的细胞特性。待解决的主要问题 解决的问题包括 (1) 受 Cd2+ 影响的细胞途径有哪些？ 导致Na+-葡萄糖共转运的抑制？ (2)什么是蜂窝 Cd2+ 形态与 Na+-葡萄糖抑制的关系 共同运输？ (3)金属硫蛋白在锌代谢中的作用 受到镉结合的困扰？ (4) 其基本化学原理是什么 金属硫蛋白控制其在细胞锌和镉中的反应性 新陈代谢和物种形成？该提案涉及三名高级调查员 凭借互补的专业知识，SSB 在文化和审查方面 肾皮质细胞的转运特性，生物无机物中的 CFS 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特性 金属蛋白。他们将使用放射性示踪剂来追踪效果 Cd2+ 对 Na+-葡萄糖共转运、转运蛋白 mRNA 合成、转运蛋白 与 Cd2+c 分布相关的生物合成和降解。一个重点是 其与 Zn-MT 蛋白的相互作用以及细胞内分布 锌以及 MT 的感应系统。相关动力学实验 MT 及其分离的 α 和 β 结构域将用于建模 镉在细胞中的形态形成和定位过程。