CELLULAR INTERACTIONS OF LEAD, CALCIUM, AND ZINC

铅、钙和锌的细胞相互作用

• 批准号: 3251896
• 负责人: Joel G Pounds
• 金额: $ 11.12万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-08-08 至 1993-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3251896
• 关键词: 1,25 dihydroxycholecalciferol; DNA binding protein; arachidonate; biological signal transduction; calcium binding protein; calcium metabolism; calmodulin dependent protein kinase; divalent metal; electrophoresis; genetic transcription; genetic translation; homeostasis; hormone receptor; hormone regulation /control mechanism; inositol phosphates; intracellular transport; laboratory rat; lead poisoning; metal metabolism; musculoskeletal circulation; ornithine decarboxylase; osteoblasts; osteocalcin; phosphorylation; receptor binding; second messengers; toxin metabolism; zinc

Lead toxicity continues to be one of the major preventable health hazards of children in this country. Recent estimates by the U.S. Department of Public Health indicate that between three and four million children are at risk for adverse health effects from lead (ATSDR, 1988). Complex interactions between lead and essential elements, primarily calcium, iron, zinc and copper are reported in the clinical and experimental literature. The mechanisms and toxicological significance of these interactions is not clearly understood. The objective of this application is to elucidate the effects of lead on hormone-signal transduction processes. This application for competitive renewal continues investigation into the cell biology of Pb2+-Ca2+ interactions, with new initiatives to elucidate the molecular site of action of Pb2+ on regulation of the osteocalcin gene. Together these experiments test the hypothesis that lead toxicity is expressed via a perturbation of the calcium messenger system and zinc-mediated cell functions. The specific aims of this proposal are to: 1. Investigate the effects of lead on the mobilization of [Ca2+]i by the second messengers myo-inositol 1,4,5-tris- phosphate or arachidonic acid in permeabilized ROS cells. Experiments will be conducted using 45Ca and ion selective electrodes to gain insight into the action of Pb2+ on second messenger function. 2. Investigate the ability of the second messengers, myo- inositol, 1,4,5-tris-phosphate and arachidonic acid to mobilize Pb2+ from intracellular stores in ROS cells. Experiments will be conducted using 210Pb to gain insight into the dynamic state of Pb+ during signal-transduction processes. 3. Characterize the effects of Pb2+ on calmodulin and protein kinase C-mediated functions. Broad spectrum effects of lead on calmodulin and protein kinase C will be established by 2-d electrophoretic analysis of protein phosphorylation. The a more specific action of Pb2+ on a protein kinase C-mediated function will be established by monitoring the hormonal regulation of ornithine decarboxylase. 4. Elucidate the mechanism of action by which inhibits the induction of osteocalcin by 1,25-dihydroxyvitamin D3 in osteoblastic bone cells focusing on the Zn2+-mediated aspects of this process. Experiments will be conducted to (a) determine the displacement of Zn2+ and binding of Pb2+ at the zinc-fingers of the 1,25(OH)2D3 receptor, (b) investigate the effects of lead on receptor translocation to the nucleus, (c) receptor binding to DNA, and finally (d) transcription and translation of the osteocalcin gene. The concepts and results developed by this project should contribute directly to understanding the skeletal metabolism of lead, the skeleton as a target of lead toxicity, and the physiological factors which may mobilize skeletal lead. The cellular and molecular concepts defining the actions of lead on hormone signal-transduction processes should also be broadly applicable to understanding the effects of lead on growth, hypertensin, and behavior and learning deficits.

铅中毒仍然是主要的可预防健康问题之一 这个国家的儿童面临的危险。 美国最近的估计 公共卫生部表示，三到四 百万儿童面临铅对健康造成不良影响的风险 （ATSDR，1988）。 铅和必需品之间复杂的相互作用 元素，主要是钙、铁、锌和铜的报道 临床和实验文献。 机制和 这些相互作用的毒理学意义尚不清楚 明白了。 该应用程序的目的是阐明 铅对激素信号转导过程的影响。 这 竞争性续展申请继续调查 Pb2+-Ca2+相互作用的细胞生物学，有新的举措 阐明 Pb2+ 对调节的分子作用位点 骨钙素基因。 这些实验共同测试了 假设铅毒性是通过扰动来表达的 钙信使系统和锌介导的细胞功能。 这 该提案的具体目标是： 1. 研究铅对动员的影响 [Ca2+]i 由第二信使肌醇 1,4,5-tris- 透化 ROS 细胞中的磷酸盐或花生四烯酸。 实验将使用 45Ca 和离子进行 选择性电极以深入了解 Pb2+发挥第二信使功能。 2. 研究第二信使肌的能力 肌醇、1,4,5-三磷酸和花生四烯酸 从 ROS 细胞的细胞内储存中调动 Pb2+。 将使用 210Pb 进行实验以获得见解 信号转导过程中进入 Pb+ 的动态状态 流程。 3. 表征 Pb2+ 对钙调蛋白和 蛋白激酶C介导的功能。 广谱 铅对钙调蛋白和蛋白激酶 C 的影响 通过蛋白质的二维电泳分析建立 磷酸化。 Pb2+ 的更具体作用 将建立蛋白激酶 C 介导的功能 通过监测鸟氨酸的荷尔蒙调节 脱羧酶。 4. 阐明抑制的作用机制 1,25-二羟基维生素 D3 诱导骨钙素 成骨细胞骨细胞专注于 Zn2+ 介导的 这个过程的各个方面。 将进行实验 (a) 确定 Zn2+ 的位移和 Zn2+ 的结合 1,25(OH)2D3 受体锌指上的 Pb2+，(b) 研究铅对受体易位的影响 (c) 受体与 DNA 结合，最后 (d) 骨钙素的转录和翻译 基因。 该项目开发的概念和成果应 直接有助于了解骨骼代谢 铅，作为铅毒性目标的骨骼，以及 可能动员骨骼铅的生理因素。 这 定义铅作用的细胞和分子概念 激素信号转导过程也应该广泛 适用于了解铅对生长的影响， 高血压、行为和学习缺陷。