Targeting FKBP52 and Copper in Alzheimer's Disease

描述(申请人提供)：AD病理的特征之一是在患者的大脑中出现神经性斑块。这些斑块由细胞外沉积的淀粉样β蛋白(Ab)组成，周围环绕着营养不良的神经突起、反应性星形胶质细胞和小胶质细胞。铜与抗体的相互作用增强抗体的聚集，并诱导抗体-铜介导的自由基形成和氧化应激的产生。推测细胞外铜可增强抗体介导的毒性，AD患者脑脊液中铜浓度和铜转运蛋白铜蓝蛋白水平升高。这一建议是基于我们最近观察到的免疫亲和素FKBP52是哺乳动物细胞铜外流途径的一个新成分，并且通过siRNA或小分子抑制剂下调FKBP52的表达来阻断Atox1-Wilson病蛋白(WDP)铜外流途径的铜外流。因此，提出了一个基本问题：FKBP52能否被用作控制铜水平和AD进展的治疗靶点？这项建议将检验这样一个假设，即靶向免疫亲和素的siRNA或小分子药物将改善两种细胞模型和小鼠APPswe/PS1dE9淀粉样变性模型中抗体病理的发展和进化。这项提议寻求解决三个具体问题。 目的#1.研究免疫亲和素配体(FK506或JNJ460)或FKBP52下调的细胞中APP的加工、抗体的产生，以及细胞内铜的定量。 目的#2.确定FKBP52下调神经元-神经胶质细胞共培养中抗体诱导的氧化损伤和神经毒性是否减轻。 目的#3.利用tet-off系统控制下的可诱导小鼠模型，以及长期使用免疫亲和素配体(FK506和JNJ460)处理的动物，研究FKBP52下调是否影响抗体沉积和抗体介导的突触病理。

DESCRIPTION (provided by applicant): One of the hallmarks of AD pathology is the presence of neuritic plaques in the brains of afflicted individuals. These plaques are composed of extracellular deposits of amyloid beta peptide (Ab) surrounded by dystrophic neurites, reactive astrocytes, and microglia. The interaction of copper with Ab enhances Ab aggregation and induces the production of Ab-Cu-mediated free radical formation and oxidative stress. It is hypothesized that Ab-mediated toxicity is potentiated by extracellular copper, and increases in the concentration of copper and the copper transport protein ceruloplasmin are found in the CSF of AD patients. This proposal is based on our recent observations that the immunophilin FKBP52 is a novel component of the copper efflux pathway in mammalian cells and down-modulation of FKBP52 expression with siRNA or small molecule inhibitors block copper efflux from the Atox1-Wilson's disease protein (WDP) copper export pathway. The basic question therefore is presented; Can FKBP52 be exploited as a therapeutic target for controlling copper levels and AD progression? This proposal will test the hypothesis that siRNA or small molecule drugs that target the immunophilin will ameliorate the development and evolution of Ab pathology in both cellular models and in a mouse APPswe/PS1dE9 model for amyloidosis. This proposal seeks to address three specific questions. Aim #1. To characterize APP processing, Ab production, and to quantify intracellular copper in cells treated with immunophilin ligands (FK506 or JNJ460) or in FKBP52-downmodulated cells. Aim #2. To determine whether Ab-induced oxidative damage and neurotoxicity is alleviated in FKBP52 down-modulated neuron-glia co-cultures. Aim #3. To investigate if Ab deposition and Ab-mediated synaptic pathology is affected by FKBP52 down-modulation using an inducible mouse model under the control of the tet-off system, and in animals chronically treated with immunophilin ligands (FK506 and JNJ460).