Copper's Role in Brain LRP-mediated Abeta Efflux and Aging

铜在大脑 LRP 介导的 Abeta 流出和衰老中的作用

• 批准号: 7372302
• 负责人: RASHID DEANE
• 金额: $ 25.26万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7372302
• 关键词: Affect; Affinity; Age; Alzheimer' s Disease; Amyloid; Amyloid beta-Protein Precursor; Apoptosis; Binding; Blood - brain barrier anatomy; Blood capillaries; Brain; Cerebrospinal Fluid; Cerebrum; Copper; Data; Dose; Down-Regulation; Endopeptidases; Endothelial Cells; Endothelium; Environmental Risk Factor; Enzyme-Linked Immunosorbent Assay; Human; In Vitro; Incubated; Insulinase; Intercellular Fluid; Ions; LDL-Receptor Related Protein 1; Lipoprotein Receptor; Low Density Lipoprotein Receptor; Mediating; Metabolic Clearance Rate; Metals; Molecular Conformation; Mus; Natural graphite; Neprilysin; Neurodegenerative Disorders; Numbers; Oryctolagus cuniculus; Peptide Hydrolases; Peptides; Plasma; Production; Protein Isoforms; Proteins; Rate; Research Proposals; Role; Sampling; Senile Plaques; Site; Testing; Time; Toxic effect; Tracer; absorption; age effect; angiogenesis; beta pleated sheet; beta-site APP cleaving enzyme 1; capillary; drinking water; in vivo; insight; monomer; neurotoxic; normal aging; novel therapeutics; protein aggregate; receptor

DESCRIPTION (provided by applicant): Accumulation of neurotoxic amyloid-¿ (A¿) species in brain is accelerated in AD. A¿ clearance by rapid transport across the blood-brain-barrier (BBB), requires LRP (low-density lipoprotein receptor-related protein1), the main receptor that clears A¿ from brain in an isoform specific manner. Copper (Cu), the focus of this research proposal, is associated with amyloid plaques in AD brains. It avidly binds A¿ and may promote betasheet conformation, aggregation and toxicity. Cu may reduce A¿ elimination from brain in rabbits, dosed with tracer levels of Cu. Our preliminary data using mice dosed with tracer levels of Cu in their drinking water showed: 1) increased Cu levels and decreased LRP protein levels in brain microvessels, 2) increased brain A¿ levels by reducing its BBB clearance and 3) no significant changes in protein levels of APP, BACE, IDE, NEP or A¿ putative receptors such as PgP and RAGE in brain microvessels. HBEC incubated with Cu (200 nM) had decreased 125I-A¿42 binding associated with LRP down-regulation, increased LRP nitrotyrosination, and enhanced LRP proteosomal degradation. In contrast, Cu did not affect HBEC-mediated angiogenesis, apoptosis, NF-?B activation. Al3+, Zn2+ and Fe3+, did not reduce LRP protein levels in HBEC at non-toxic concentrations. We hypothesize that A¿ clearance across the BBB is reduced in normal mice dosed with tracer levels of Cu due to Cu-induced decrease in LRP levels in cerebral endothelium, the BBB site in vivo, and that this effect is potentiated with normal aging. Four aims are proposed. Aim 1. The role of Cu on LRPmediated soluble A¿ monomers clearance across the normal mouse BBB in vivo and effect of aging. Aim 2. The role of Cu on LRP-mediated soluble A¿ oligomers clearance across the mouse BBB in vivo and effect of aging. Aim 3. The role of Cu on soluble A¿ (monomers and oligomers) LRP binding and internalization in mouse brain capillaries. Aim 4. The role of Cu on LRP levels, synthesis and turnover in human brain endothelial cells. We will study clearance of A¿40 and A¿42 monomers and oligomers from the CNS in vivo and determine efflux at the BBB in control and Cu-dosed mice, at selected ages (4,9,15 and 24 months, after dosing), as well as in vitro using isolated brain capillaries. Mouse endogenous A¿ levels in brain, cerebrospinal fluid (CSF) and plasma will be determined by ELISA. Cu levels in these samples and in brain microvessels will be determined by graphite furnace atomic absorption spectrophotometer. The effects of Cu on LRP levels, turnover and synthesis will be determined in brain endothelial cells. The proposed study will, for the first time, define Cu's role in the modulation of soluble A¿ transport from brain, and provide new therapeutic insights on how to lower brain A¿ by controlling its CNS barriers transport in Cu-potentiated neurodegenerative disorders. Project narrative: Accumulation of neurotoxic amyloid-¿ (A¿) species in brain is accelerated in AD. A¿ clearance by rapid transport across the blood-brain-barrier (BBB), requires LRP (low-density lipoprotein receptor-related protein1), the main receptor that clears A¿ from brain. Copper (Cu) is associated with amyloid plaques in AD brains. It avidly binds A¿ and may promote beta-sheet conformation, aggregation and toxicity. Our pilot data showed that mice, dosed with tracer levels of Cu in their drinking water, accumulates Cu in brain microvessels, and this effect is associated with down-regulation of LRP protein levels in these microvessels and increased A¿ retention in brain. We are proposing a new role for Cu. We suggest that Cu down-regulates LRP in brain microvessels, and that this effect contributes to brain A¿ accumulation. The proposed study will, for the first time, define Cu's role as an environmental factor in the modulation of soluble A¿ transport from brain. These studies may provide new therapeutic insights on how to lower brain A¿ by controlling its CNS barriers transport in Cu-potentiated neurodegenerative disorders.

描述（由申请人提供）：神经毒性淀粉样蛋白的积累（A）大脑中的物种是在AD中解释的。通过跨血脑屏障（BBB）快速运输（主要或清除A从同工型特异性（Cu）s a。从大脑并可能促进Betasheet的契约，聚集和毒品。从兔子中消除大脑，用示踪剂水平的Cu降低。通过降低其BBB清除率和3）App，bace，IDE，NEP的蛋白质水平没有显着变化 或a？脑微血管中的推定受体，例如PGP和愤怒。 42与LRP下去的结合，并增强了LRP蛋白体降解。我们假设一个在正常小鼠的固定剂水平上，cu诱导的LRP水平降低了BBB的清除率在体内降低了LRP水平，并且该效果通过正常的衰老而增强。一个单体closs在体内的正常小鼠BBB和衰老的效果。寡聚物在体内跨BBB及衰老的影响。 （单体和低聚物）在小鼠脑毛细血管中的LRP结合和内在化。 40和A 42个来自中枢神经系统的单体和低聚物在对照和CU剂量的MICS（4,9,15和24个月G）以及使用分离的脑毛细管的体外确定BBB的外排。在大脑中，Ceresma将通过ELISA确定，raphite炉吸收分光光度计。可溶性的调节从大脑运输，并提供有关如何降低大脑a的新治疗见解通过控制其CU启用神经退行性障碍中的CNS屏障。 （A）大脑中的物种是在AD中解释的。通过跨血脑屏障（BBB）快速运输（主要或清除A来自大脑（CU）。并可能促进Beta表格，聚集和毒品。我们的飞行员数据表明​​，小鼠会在脑部微型固定中累积Cu，并且这种效果与这些微观无关的LRP蛋白水平的下调有关，并增加了A ??我们提出了CU的新角色。积累。这些研究可以从大脑中运输。通过控制其CU启动神经退行性疾病中的CNS屏障传输。