权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

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

基本信息

批准号：
7800884
负责人：
RASHID DEANE
金额：
$ 25万
依托单位：
UNIVERSITY OF ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-04-01 至 2013-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7800884
关键词：
Affect Affinity Age Alzheimer&apos s Disease Amyloid Amyloid beta-Protein Precursor Apoptosis Binding Blood - brain barrier anatomy Blood capillaries Brain Cerebrospinal Fluid Cerebrum Copper Data Dose Down-Regulation 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 Oryctolagus cuniculus Peptide Hydrolases Peptides Plasma Production Protein Isoforms Proteins 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

项目摘要

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）：AD 中大脑中神经毒性淀粉样蛋白 (A¿) 的积累加速。 A¿ 通过快速转运穿过血脑屏障 (BBB) 进行清除，需要 LRP（低密度脂蛋白受体相关蛋白 1），LRP 是以同种型特异性方式从大脑中清除 A¿ 的主要受体。铜 (Cu) 是本研究提案的重点，它与 AD 大脑中的淀粉样斑块有关。它强烈地结合A¿，并可能促进β片层构象、聚集和毒性。服用示踪剂水平的 Cu 可能会减少兔子大脑中 A¿ 的消除。我们使用在饮用水中添加示踪剂浓度的小鼠进行的初步数据显示：1）大脑微血管中的铜水平增加并降低了 LRP 蛋白水平，2）通过降低 BBB 清除率增加了大脑 A¿ 水平，3）APP、BACE、IDE、NEP 的蛋白水平没有显着变化或 A? 脑微血管中的推定受体，例如 PgP 和 RAGE。与 Cu (200 nM) 一起孵育的 HBEC 降低了与 LRP 下调相关的 125I-A¿42 结合，增加了 LRP 硝基酪氨酸化，并增强了 LRP 蛋白体降解。相反，Cu不影响HBEC介导的血管生成、细胞凋亡、NF-κB激活。 Al3+、Zn2+ 和 Fe3+ 在无毒浓度下不会降低 HBEC 中的 LRP 蛋白水平。我们推测，在服用示踪剂水平的 Cu 的正常小鼠中，由于 Cu 诱导脑内皮（体内 BBB 位点）中 LRP 水平降低，A¿ 穿过 BBB 的清除率降低，并且这种效应随着正常衰老而增强。提出了四个目标。目的 1. Cu 对 LRP 介导的可溶性 A¿ 单体穿过正常小鼠体内血脑屏障的清除的作用以及衰老的影响。目标 2. Cu 对 LRP 介导的可溶性 A¿ 寡聚物在体内穿过小鼠 BBB 的清除的作用以及衰老的影响。目标 3. Cu 对小鼠脑毛细血管中可溶性 A¿（单体和低聚物）LRP 结合和内化的作用。目标 4. Cu 对人脑内皮细胞 LRP 水平、合成和周转的作用。我们将在体内研究 A¿40 和 A¿42 单体和寡聚体从 CNS 的清除情况，并确定对照小鼠和 Cu 给药小鼠在选定年龄（给药后 4、9、15 和 24 个月）的 BBB 的流出，以及使用分离的脑毛细血管进行体外研究。将通过 ELISA 测定小鼠脑、脑脊液 (CSF) 和血浆中的内源性 A¿ 水平。这些样本和脑微血管中的铜含量将通过石墨炉原子吸收分光光度计测定。 Cu 对 LRP 水平、周转和合成的影响将在脑内皮细胞中确定。这项拟议的研究将首次明确铜在调节可溶性 A 的大脑转运中的作用，并为如何通过控制铜增强的神经退行性疾病中的 CNS 屏障转运来降低脑 A 提供新的治疗见解。项目叙述：AD 患者大脑中神经毒性淀粉样蛋白 (A¿) 的积累加速。 A¿ 通过快速转运穿过血脑屏障 (BBB) 进行清除，需要 LRP（低密度脂蛋白受体相关蛋白 1），它是从大脑中清除 A¿ 的主要受体。铜 (Cu) 与 AD 大脑中的淀粉样斑块有关。它强烈地结合 A¿，并可能促进 β-折叠构象、聚集和毒性。我们的试验数据表明，在饮用水中添加示踪剂浓度的小鼠，其脑微血管中会积累铜，这种效应与这些微血管中 LRP 蛋白水平的下调和大脑中 A¿ 保留的增加有关。我们正在为 Cu 提议一个新角色。我们认为 Cu 会下调脑微血管中的 LRP，并且这种效应有助于脑 A 的积累。拟议的研究将首次定义铜作为调节大脑可溶性 A 运输的环境因素的作用。这些研究可能为如何通过控制铜增强神经退行性疾病中的 CNS 屏障转运来降低脑 A 提供新的治疗见解。