Mimicry of Amyloid Oligomers

描述（由申请人提供）：多肽和蛋白质的聚集是许多破坏性神经退行性疾病的核心，包括阿尔茨海默病、亨廷顿病和朊病毒疾病。尽管淀粉样原纤维一直被视为阿尔茨海默病和其他神经退行性疾病的标志，但淀粉样原肽形成的低聚物已开始成为阿尔茨海默病和其他神经退行性疾病中更重要的神经毒性物质。原纤维采用层状β片结构。虽然低聚物的结构才刚刚开始出现，但它们似乎也涉及β -片的形成，可能涉及分层和相关的疏水相互作用。模拟淀粉样蛋白低聚物结构的强大模型系统的发展不仅提供了对淀粉样蛋白低聚物结构和生物活性的见解，而且还提供了控制涉及β -片形成的肽和蛋白质相互作用的新工具。该项目将通过开发专门用于稳定β -片间相互作用的链间和片间交联来解决稳定小寡聚β -片的问题。这些交联将使用PI实验室开发的大环β片来开发。大环β片形成氢键二聚体，通过疏水相互作用进一步自组装，形成三明治状结构。片间交联将用于稳定层状结构和控制自组装。将开发页内交联以实现平行的β -页结构。含有这些交联的大环β片将被用来模拟淀粉样β肽二聚体的结构。淀粉样蛋白低聚物模拟物的结构将通过核磁共振波谱、x射线晶体学和其他生物物理技术进行评估。这些分子和分子组合模拟淀粉样β -肽低聚物的能力将通过使用寡聚物特异性抗体和神经细胞来比较它们与天然淀粉样β -肽低聚物的行为来评估。我们将在小鼠海马切片和大鼠器官型切片中研究淀粉样蛋白寡聚物模拟物对突触长时程增强、长时程突触抑制和突触树突棘密度的影响。

DESCRIPTION (provided by applicant): The aggregation of peptides and proteins is central to many devastating neurodegenerative disorders, including Alzheimer's disease, Huntington's disease, and the prion diseases. Although amyloid fibrils have long been viewed as the hallmark of Alzheimer's and other neurodegenerative diseases, the oligomers formed by amyloidogenic peptides have begun to emerge as the more important neurotoxic species involved in Alzheimer's and other neurodegenerative diseases. The fibrils adopt layered beta-sheet structures. Although the structures of the oligomers are only beginning to emerge, they appear to also involve beta-sheet formation and may involve layering and related hydrophobic interactions. The development of robust model systems to mimic the structure of amyloid oligomers offers the promise of not only providing insights into the structures and biological activities of amyloid oligomers, but also providing new tools with which to control peptide and protein interactions involving beta-sheet formation. This project will approach the problem of stabilizing small oligomeric beta-sheets by developing interstrand and intersheet crosslinks tailored to stabilize interactions between beta-sheets. These crosslinks will be developed using macrocyclic beta-sheets developed in the PI's laboratory. The macrocyclic beta-sheets form hydrogen-bonded dimers that further self-assemble through hydrophobic interactions to form sandwich-like structures. Intersheet crosslinks will be developed to stabilize the layered structures and control self-assembly. Intrasheet crosslinks will be developed to achieve parallel beta-sheet structures. Macrocyclic beta-sheets containing these crosslinks will be used to mimic the structure of the amyloid beta-peptide dimer. The structures of the mimics of amyloid oligomers will be evaluated by NMR spectroscopy, X-ray crystallography, and other biophysical techniques. The ability of these molecules and molecular assemblies to mimic amyloid beta-peptide oligomers will be evaluated by using oligomer-specific antibodies and neuronal cells to compare their behavior to natural amyloid beta-peptide oligomers. The effect of promising amyloid oligomer mimics on long-term potentiation, long-term synaptic depression, and dendritic spine density at synapses will be studied in mouse hipocampal slices and rat organotypic slices.