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

在这项提议中，我们想要检验这样一种假设，即定义的Aβ多肽变体以特定的方式有助于阿尔茨海默病(AD)的发病和进展。淀粉样斑块中沉积的Aβ多肽是AD的组织病理学特征。然而，人们普遍认为不是淀粉样斑块，而是它们的寡聚体和纤维前体损害神经功能并具有神经毒性。Abeta多肽代表一组具有不同生物物理和细胞生物学特性的多肽，这些多肽通过N末端截断和其他特定的翻译后修饰而多样化。然而，已定义的Abeta多肽变体在AD的发生和发展中的作用尚未完全确定。因此，我们希望利用已有的和我们产生的新的单抗，通过免疫组织化学和生化方法对脑实质和血管中磷酸化、硝化、焦谷氨酸和异天冬氨酸修饰的Abeta多肽进行比较分析。我们将分析有症状前和有症状的阿尔茨海默病患者的死后人脑组织，并与对照组和患有血管性痴呆和路易体痴呆的患者的脑组织进行比较。此外，我们还将揭示在原代培养的神经细胞中修饰的Abeta多肽的聚集特性和神经毒性特征。综上所述，这些结果应该揭示这些修饰形式的Abeta是否由于它们在大脑和神经毒性中的时空表达模式而代表着疾病进展的强大驱动因素。

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.