Differentiating Abeta40/42 in plaques with small molecule fluorescent probes

使用小分子荧光探针区分斑块中的 Abeta40/42

• 批准号: 10507501
• 负责人: Chongzhao Ran
• 金额: $ 45.93万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10507501
• 关键词: Age; Alanine; Alzheimer' s Disease; Alzheimer' s disease brain; Alzheimer' s disease pathology; Amino Acid Sequence; Amino Acids; Amyloid beta-Protein; Antibodies; Area; Aspartate; Autopsy; Brain; C-terminal; Cells; Cryoelectron Microscopy; Dendritic Spines; Development; Disease Progression; Environment; Enzyme-Linked Immunosorbent Assay; Epitopes; Fluorescence; Fluorescent Probes; Future; Human; Hydrophobicity; Image; Imaging technology; Immune; Impaired cognition; In Vitro; Isoleucine; Knowledge; Length; Lysine; Machine Learning; Mission; Molecular Probes; Monitor; Morphology; Mus; N-terminal; Neurites; Oral cavity; Pathology; Peptides; Performance; Play; Property; Roentgen Rays; Role; Senile Plaques; Severities; Shapes; Site; Slide; Stains; Structure; Surface; Technology; Testing; Tissue Extracts; Tissue Stains; base; brain tissue; design; histological stains; hydrophilicity; imaging modality; in vitro testing; neuron loss; neurotoxicity; preclinical study; protein aminoacid sequence; small molecule

Amyloid beta (Aβ) plaques constitute one of the most distinctive morphological hallmarks of Alzheimer’s disease (AD). In the past decades, the contribution of Aβ plaques to the overall cognitive decline in AD has been debated extensively. Postmortem studies suggest that plaque abundance does not correlate strongly with the severity of sporadic AD. Conversely, preclinical studies provide strong evidence that plaques are clear sites of pathology and are associated with dystrophic neurites, the loss of dendritic spines and rapid neuron cell death in their surroundings. In the plaques, A40 and A42 peptides are the major constituents. Nonetheless, unlike the role of plaque, there is nearly no argument that A42 has a much higher neurotoxicity than A40 does. Conceivably, differentiating A40 and A42 can considerably clarify the role of plaque in AD pathology. Differentiating A40 and A42 has long been considered as an impossible mission with small-molecule probes, due to the small difference in the amino acid sequence of the peptides. It is obvious that the C-terminal of A peptide is the key for designing small-molecule probes to distinguish them, because the only difference of two amino acids (isoleucine-alanine) is within the C-terminals of A40/42 peptides. There is no prior knowledge to teach us how to design such probes. Nonetheless, it has been routinely performed with anti-A42 antibodies to determine the contents of A42 in cell media and brain extracts. These anti-A42 antibodies were designed based on the epitope of the C-terminal of the peptide. This fact has bolstered us to believe that the properties of the C-terminal can be relied on to design our small molecule probes. In the past, X-ray structures of full-length As were rare. However, recently the advanced Cryo-EM technology has impressively facilitated A structure studies. In our preliminary results, based on the unique environment of the C-terminal, we designed small- molecule fluorescence probe ICTAD-1 that has the capacity to spectrally differentiate A40/42 in vitro and brain slides. In this proposal, we plan to design new probes and validate their capacity for differentiating A40/42.

β淀粉样蛋白（Aβ）斑块是阿尔茨海默病最独特的形态学标志之一 （AD）。在过去的几十年里，Aβ斑块对AD整体认知能力下降的贡献一直存在争议 广泛地。尸检研究表明，斑块的丰富程度与严重程度并不密切相关。 零星AD。相反，临床前研究提供了强有力的证据，表明斑块是明确的病理部位 并与神经营养不良的神经突，树突棘的损失和快速神经元细胞死亡有关， 四周在斑块中，A β 40和A β 42肽是主要成分。然而，与角色不同， 几乎没有争论A β 42比A β 40具有更高的神经毒性。可以想象， 区分A β 40和A β 42可以相当清楚地阐明斑块在AD病理中的作用。 区分A β 40和A β 42一直被认为是小分子探针不可能完成的使命， 这是由于肽的氨基酸序列差异很小。很明显，A β的C-末端 肽是设计小分子探针区分它们的关键，因为两者的唯一区别是 氨基酸（异亮氨酸-丙氨酸）在A β 40/42肽的C末端内。没有事先的知识， 教我们如何设计这样的探测器。尽管如此，它已经常规地用抗A β 42抗体进行， 测定细胞培养液和脑提取液中A β 42的含量。这些抗A β 42抗体被设计为 基于肽的C-末端的表位。这一事实使我们相信， C-末端可以用来设计我们的小分子探针。在过去，全长的X射线结构 A级是罕见的。然而，近年来，先进的冷冻电镜技术已经令人印象深刻地促进了A β结构 问题研究在我们的初步成果中，基于C端的独特环境，我们设计了小- 本发明提供了一种能够在体外光谱上区分A β 40/42和脑内光谱的分子荧光探针IC 50 -1， 公里.在本提案中，我们计划设计新的探头，并验证其区分A/40/42的能力。