D-青霉胺抑制阿尔茨海默病转基因小鼠脑内β-淀粉样蛋白沉积及其机制研究

阿尔茨海默病(AD) 的主要病理特征之一是脑内出现β-淀粉样蛋白(Aβ)沉积形成的老年斑。铜、锌金属离子可通过与Aβ分子的组氨酸位点结合促进其脑内沉积，体外实验证实金属离子螯合剂D-青霉胺(D-Pen)能有效降低Aβ聚集，用纳米粒包裹的D-Pen可穿越血脑屏障进入脑组织，但D-Pen是否能抑制AD脑内Aβ沉积及其机制尚不清楚。本项目拟制备D-Pen与纳米粒共价结合的脑靶向药物传递系统，通过鼻饲处理APP/PS1转基因小鼠，结合D-Pen处理转染人APP的细胞模型，应用分子生物学和行为学等手段，检测D-Pen抑制脑内铜锌离子蓄积和Aβ的产生，改善小鼠学习记忆能力的作用，分析D-Pen对β-淀粉样蛋白前体蛋白(APP)及其剪切酶β-分泌酶、γ-分泌酶等表达的影响，明确D-Pen抑制Aβ产生与老年斑形成的可能途径，为揭示D-Pen防治AD的作用与机理，以及指导金属螯合剂类药物研发提供理论基础。

Alzheimer's disease (AD) is a neurodegenrative disorder characterized with β-amyloid protein (Aβ) deposition and plaque formation in the brain. Aβ is generated from β-amyloid precursor protein (APP) via a proteolytic process of β- and γ-secretases. Recent studies have shown that metal ions, such as copper and zinc, accumulated and combined with Aβ peptides in AD brain. Interestingly, the metal-protein attenuating compounds (MPAC) are able to compete metal ions with Aβ, reduce the activity of β- and γ-secretase, and decrease Aβ secretion/deposition in AD transgenic mouse brain. D-penicillamine (D-Pen) is a classical MPAC wich has been used for Wilson's disease therapy for decades. Recently in vitro studies have shown that D-Pen could effectively resolubilize copper-Aβ aggregates. Furthermore, D-Pen nanoparticles could release the conjugated D-Pen thorough the brain blood barrier into the brain. However, the effect and the underlying mechanism of whether D-Pen is able to inhibit Aβ deposition in AD brain has not been evaluated. In this project, we will use the D-Pen nanoparticles to treat the APP/PS1 transgenic mouse, to evaluate the effects of D-Pen on the reduction of metal ione levels and the inhibition of Aβ generation related secretase activity in APP/PS1 transgenic mouse brain. Hopefully, this project will explore the mechanisms by which D-Pen modulates the activity of Aβ generation related secretases, and provide a clue for potential use of D-Pen for the prevention and therapy of AD.