Signatures of modified Abeta peptides in brains of Alzheimer’s disease subjects revealed by novel monoclonal antibodies

在这个提议中，我们想要验证一个假设，即确定的β肽变异以一种特定的方式促进阿尔茨海默病（AD）的发病和进展。淀粉样斑块中β肽的沉积是阿尔茨海默病的组织病理学标志。然而，人们普遍认为不是淀粉样斑块，而是它们的低聚体和原纤维前体损害神经元功能并具有神经毒性。β肽是一种多肽，具有不同的生物物理和细胞生物学特性，通过n端截断和其他特定的翻译后修饰而多样化。然而，定义的β肽变体对AD的发生和进展的贡献尚未完全确定。因此，我们希望利用已有的单克隆抗体和新的单克隆抗体，通过免疫组织化学和生化方法对脑组织和血管中磷酸化、硝化、焦谷氨酸和异天冬氨酸修饰的Abeta肽进行比较分析。我们将分析症状前和症状性AD患者的死后脑组织，并与对照组、血管性痴呆和路易体痴呆患者的脑组织进行比较。此外，我们将揭示在原代神经细胞培养中修饰的β肽的聚集特征和神经毒性特征。总之，结果应该揭示这些修饰形式的Abeta是否可能代表疾病进展的有效驱动因素，因为它们在脑和神经毒性中的空间和时间表达模式。

In this proposal we would like to test the hypothesis that defined Abeta peptide variants contribute to the pathogenesis and progression of Alzheimer’s disease (AD) in a specific manner. Deposits of Abeta peptides in amyloid plaques are a histopathological hallmark of AD. However, it is generally accepted that not amyloid plaques, but their oligomeric and fibrillary precursors compromise neuronal function and are neurotoxic. Abeta peptides represent a heterogeneous group of peptides with differing biophysical and cell biological characteristics that are diversified by N-terminal truncation and other specific post-translational modifications. However, the contributions of defined Abeta peptide variants to the initiation and progression of AD are not fully established. Therefore, we would like to employ already existing and novel monoclonal antibodies generated by us for the comparative analyses of phosphorylated, nitrated, pyroglutamate- and isoaspartate-modified Abeta peptides in brain parenchyma and vessels by immunohistochemical and biochemical methods. We will analyze post mortem human brain tissue from pre-symptomatic and symptomatic AD cases in comparison to brain tissue from control subjects and subjects who suffered from vascular dementia and from dementia with Lewy bodies. Additionally, we will reveal aggregation characteristics and neurotoxic profiles of modified Abeta peptides in primary neuronal cell cultures. In summary, the results should reveal whether these modified forms of Abeta might represent potent drivers of disease progression due to their spatial and temporal expression patterns in brain and neurotoxicity.