双光子吸收材料对阿尔兹海默氏症淀粉蛋白识别和抑制研究

Alzheimer’ s disease (AD) stands out among the etiologies of acquired dementia and is becoming an extensive health problem with the ever-increasing aging population. Generally, it has been thought that the extracellular accumulation of β-amyloid (Aβ) peptides into plaques plays a vital role in AD onset. Since two-photon absorption materials are particularly attractive for live cell based samples, facilitating the deep tissue imaging with free back ground noise. In this proposal we try to apply two-photon absorption ligand/complex probes to recognize and inhibit Aβ-plaques with high specificity; further peptide modification may also lead to active blood-brain barrier (BBB) targeting. The photophysical properties between Aβ/Aβ-plaques and ligand/complex will be carefully evaluated in vitro. Through Computer docking model, in vitro BBB model and animal disease model, the key issues that Aβ-plaque targeting mechanism using two-photon absorption ligand/complex will be fully investigated under molecular level. The in vivo biodistribution and primary AD clinical effect will be also assessed under two-photon confocal microscopy. It is anticipate that the implementation of this project will offer new idea to design Aβ probes with two-photon absorption property; as well as providing novel methodologies for AD diagnoses and therapy.

随着全球老龄社会的到来，阿尔兹海默氏症造成的问题日益严重。对淀粉蛋白(Aβ沉淀)识别和抑制是治疗阿尔兹海默氏症的关键科学问题。本项目针对阿兹海默氏症Aβ沉淀的特点和成因，利用在生物体内具有低能量激发，穿透性强、背景光干扰小等优点的双光子吸收材料，设计合成具有识别和抑制Aβ沉淀的双光子活性配体及配合物探针；利用小分子肽链修饰配体及配合物，构筑对血脑屏障主动靶向的体系。在体外测试双光子活性配体/配合物与Aβ作用的光物理性质。通过模拟分子对接与三维血脑屏障模型、动物模型相结合，在分子水平和三维动物模型上研究中枢神经靶向和Aβ靶向的作用机理等关键科学问题。利用双光子共聚焦显微技术观察双光子吸收材料在体内的分布和与Aβ沉淀的作用效果，探索材料在阿兹海默氏症诊断和治疗方面的应用。本项目的实施为识别和抑制Aβ沉淀的双光子吸收材料的设计提供新思路，研究成果将为靶向分子对阿兹海默氏症的诊断和治疗提供新方法。

寻找高效的分子靶向体系，实现近红外光识别检测和抑制Aβ淀粉样沉淀，在治疗阿兹海默氏症占有重要地位。本项设计、合成及修饰具有透过血脑屏障、识别Aβ沉淀并可以与金属离子配位的双光子材料，利用双光子材料穿透力强、背景干扰小、光毒性低、定位能力强等优势，识别和抑制Aβ沉淀；建立血脑屏障的平面模型和3D模型，研究新型双光子材料的摄取机理、神经毒性、Aβ识别以及在小鼠阿兹海默氏症模型上的靶向性、药效学和药动学，实现双光子材料对阿兹海默氏症的高效检测和抑制。项目首先设计合成具有对淀粉样沉淀中金属离子螯合能力的双光子活性配体/配合物，利用配体中的氨基、羧基修饰G23和Angiopep-2等肽链，得到具有大脑靶向性双光子荧光探针；然后，利用β-amyloid蛋白溶液检测分子的识别效果，以及对β-amyloid沉淀的解离作用。建立平面细胞模型，测试目标分子对神经细胞内外的β-amyloid靶向效果、对巨噬细胞和白细胞的免疫反应。在立体细胞模型上测试目标分子对血脑屏障的通透性。利用脑血管内皮细胞、神经细胞、星状细胞等建立3D细胞模型，测试目标分子对血脑屏障的通透性及渗透效率。进一步利用活体成像、药物动力、切片成像等手段，评估配体分子在小鼠模型上的分布、对大脑内β-amyloid的靶向的效果。本项目研究将在脑靶向光功能探针及探索脑靶向细胞机制方面取得了原创性成果。