ACTION OF DMSA ON CELLULAR LEAD METABOLISM AND TOXICITY

DMSA 对细胞铅代谢和毒性的作用

• 批准号: 3253861
• 负责人: Joel G Pounds
• 金额: $ 11.83万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-15 至 1994-08-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3253861
• 关键词: bone metabolism; chelating agents; cytotoxicity; environmental toxicology; hemoprotein metabolism; kidney cell; kidney metabolism; laboratory rat; lead; lead poisoning; metal complex; metal metabolism; osteoblasts; osteocalcin; osteocytes; porphyrin metabolism; radionuclides; radiotracer; succinates; tissue /cell culture

Lead (Pb) toxicity is the most common preventable disease in the pediatric age group today in the United States. In its 1988 report to Congress, the U.S. Public Health Service estimated that 5 million or more young children are at high risk from all sources of Pb, including food, drinking water, dust, dirt and gasoline, and paint. Unfortunately, this disease will continue for many years, because there are still over 40 million dwellings nationally that contain hazardous quantities of leaded paint. Numerous studies have investigated the actions of chelating agents on lead metabolism in animals and humans, including selective removal from soft tissues and the skeleton, and altered tissue deposition of metal-chelator complexes. The most critical measure(s) of chelator efficacy are the ability to (a) reduce cellular lead burden, (b) restore or prevent Pb- induced loss of cell function, and (c) not produce adverse effects by interfering with homeostasis and utilization of essential trace elements. Little is currently known regarding the action of meso-2,3- dimercaptosuccinic acid (DMSA), an orphan chelating drug, on cellular lead metabolism. The questions to be addressed in this application include, How much lead must be removed, and from which subcellular kinetic pool, to provide restoration of biochemical function (porphyrin, heme, and osteocalcin production) to the cells? together, these experiments will test the hypothesis that DMSA will decrease the cellular burden of lead in critical target within kinetically distinct intracellular kinetic pools of lead, and that reduction the amount of lead in these pools leads to a selective restoration of cell function. The experiments will be conducted in cultured renal proximal tubule cells (PCT) and in clonal osteoblastic bone cells (ROS 17/2.8). Three specific aims are to: 1. Characterize and compare the ability of DMSA to reduce the cellular burden of lead by evaluating the action of DMSA on the steady state kinetics of 210Pb in cultured renal tubule and osteoblastic bone cells. 2. Characterize the potential for DMSA to increase movement of Pb2+ into cells by evaluating the steady state kinetics of 210Pb administered as the 210Pb-DMSA complex, in cultured renal tubule and osteoblastic bone cells. 3. Characterize the ability of DMSA to restore cellular function in lead intoxicated cells by evaluating the restoration of porphyrin and hemoprotein production in renal tubule and osteoblastic bone cells, and the recovery of osteocalcin production in osteoblasts. In summary, this project will characterize the ability of DMSA to reduce the subcellular burden of lead in two important target cells for lead toxicity using a kinetic model for 210Pb metabolism and correlate these changes in intracellular lead metabolism with three important biochemical and clinical measures of lead toxicity. These studies will (a) contribute to understanding the basic mechanisms and processes of chelator action at the cellular level, (b) provide a basis for designing more effective and safer chelating drugs, and (c) provide a link between chelator action at the cellular level with clinical and animal studies.

铅中毒是儿童最常见的可预防疾病 年龄组在美国。 在1988年提交给国会的报告中， 美国公共卫生服务部门估计， 所有来源的铅，包括食物，饮用水， 灰尘、泥土、汽油和油漆。 不幸的是，这种疾病将 这一现象将持续多年，因为仍有超过4000万套住房 含铅油漆的危险数量。 许多研究已经调查了螯合剂对铅的作用 在动物和人类的代谢，包括选择性地从软 组织和骨骼，并改变金属螯合剂的组织沉积 配合物 螯合剂功效的最关键量度是 （a）降低细胞铅负荷，（B）恢复或预防铅- 诱导细胞功能丧失，和（c）不产生不利影响， 干扰体内平衡和必需微量元素的利用。 目前对meso-2，3- 二巯基琥珀酸（DMSA），一种孤儿螯合药物，对细胞铅 新陈代谢. 本申请中要解决的问题包括： 必须去除大量的铅，并从亚细胞动力池中去除， 提供生化功能的恢复（卟啉，血红素， 骨钙素的产生）对细胞的影响？ 这些实验将 测试DMSA将降低细胞铅负荷的假设， 在动力学上不同的细胞内动力学池内的关键靶点， 铅，这些铅池中铅含量减少导致 选择性恢复细胞功能。 实验将在 在培养的肾近端小管细胞（PCT）和克隆成骨细胞中， 骨细胞（ROS 17/2.8）。 三个具体目标是： 1.表征并比较DMSA减少细胞凋亡的能力。 通过评估DMSA对稳态的作用， ~（210）Pb在体外培养的肾小管和成骨细胞中的动力学研究 2.表征DMSA增加Pb 2+进入 通过评估稳态动力学的210铅管理的细胞作为 210 Pb-DMSA复合物，在培养的肾小管和成骨细胞。 3.表征DMSA恢复铅细胞功能的能力 通过评估卟啉的恢复， 在肾小管和成骨细胞中产生血红素蛋白， 成骨细胞中骨钙素产生的恢复。 总之，该项目将描述DMSA减少 铅在两种重要靶细胞中亚细胞负荷 毒性使用210铅代谢动力学模型，并将这些 细胞内铅代谢的变化与三个重要的生化 和铅毒性的临床测量。 这些研究将（a）有助于 了解螯合剂作用的基本机制和过程， 细胞水平，（B）为设计更有效和 更安全的螯合药物，和（c）提供螯合剂作用与 细胞水平与临床和动物研究。