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.

铅毒性仍然是主要可预防的健康之一 这个国家的儿童危害。 美国的最新估计 公共卫生部表明三到四 百万儿童有潜在客户受到不利健康影响的风险 （ATSDR，1988）。 铅与必需品之间的复杂相互作用 据报道，元素，主要是钙，铁，锌和铜 临床和实验文献。 机制和 这些相互作用的毒理学意义并不清楚 理解。 此应用的目的是阐明 铅对激素信号转导过程的影响。 这 竞争性更新的申请继续调查 PB2+ -CA2+相互作用的细胞生物学，并带有新计划 阐明PB2+对调节的作用分子位点 骨钙素基因。 这些实验一起测试了 铅毒性的假设是通过扰动表达的 钙信使系统和锌介导的细胞功能。 这 该提案的具体目的是： 1。研究铅对动员的影响 [Ca2+] i由第二个使者肌醇1,4,5-tris-- 透化ROS细胞中的磷酸盐或蛛网膜酸。 实验将使用45CA和离子进行 选择性电极以深入了解 pb2+在第二使者功能上。 2。调查第二使者的能力，myo- 肌醇，1,4,5-三磷酸和花生四烯酸至 从ROS细胞中的细胞内存储中动员PB2+。 实验将使用210pb进行洞察力 在信号转导过程中进入PB+的动态状态 过程。 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的影响将 可以通过蛋白质的二-D电泳分析建立 磷酸化。 PB2+更具体的动作 将建立蛋白激酶C介导的功能 通过监测鸟嘌呤的激素调节 脱羧酶。 4。阐明了抑制的作用机理 通过1,25-二羟基维生素D3诱导骨钙素诱导 关注Zn2+介导的成骨细胞细胞 这个过程的各个方面。 将进行实验 到（a）确定Zn2+的位移和结合 1,25（OH）2d3受体的锌膜的Pb2+，（b） 研究铅对受体易位的影响 到核，（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结果应该 直接有助于理解的骨骼代谢 铅，骨骼作为铅毒性的目标， 可能动员骨骼铅的生理因素。 这 细胞和分子概念定义铅对 激素信号转导过程也应广泛 适用于了解铅对增长的影响， 高血压，行为和学习缺陷。