Misfolding and aggregation of polyglutamine sequences in neurodegenerative diseases

 描述（由申请人提供）：累积的、异常折叠的蛋白质的形成与20多种不同的临床综合征有关，每种临床综合征与不同的“错误折叠”蛋白质有关。这些错误折叠的蛋白质聚集并形成许多神经退行性疾病的标志，称为淀粉样蛋白。淀粉样蛋白形成与神经变性疾病如阿尔茨海默氏病、帕金森氏病和亨廷顿氏病以及局部疾病如II型糖尿病相关。在淀粉样蛋白相关疾病中，多聚谷氨酰胺（polyQ）疾病代表一组遗传性神经障碍，包括至少九种疾病。在polyQ疾病如亨廷顿氏病（HD）中，我们对polyQ的扩张如何以及为什么导致聚集和淀粉样蛋白形成的认识在很大程度上受到这样一个事实的阻碍，即对这一过程几乎没有高分辨率的结构和动态见解。此外，polyQ蛋白错误折叠种类参与异常蛋白质相互作用的能力已经得到越来越多的研究。特别是，polyQ蛋白与分子伴侣的相互作用及其对蛋白水解的抗性知之甚少。polyQ蛋白所带来的挑战是多方面的，因此，为解决这些问题而开发的新的生物化学和生物物理方法将大大有助于我们对polyQ疾病的理解。为了实现这一目标，本申请试图通过使用核磁共振（NMR）光谱进一步研究高分辨率的polyQ蛋白的聚集特性，即亨廷顿蛋白的N-末端片段（涉及HD的进展）。新开发的NMR方法，如暗态交换饱和转移（DEST）和寿命谱线展宽，提供了在polyQ蛋白自组装中发生的动态交换上实现原子分辨率的能力，除了它们与分子伴侣如Hsp 70和Hsp 40的相互作用。虽然这项建议将侧重于新的NMR方法的开发和应用，这些具有挑战性的系统，该研究将扩展到使用各种其他生物物理技术，包括电子顺磁共振（EPR），荧光光谱和量热法的调查。通过polyQ蛋白对淀粉样蛋白形成的拟议研究的结果将显着推进我们对HD和其他polyQ疾病的理解，一般来说，通过实现原子级分辨率的结构和动态见解，并将有助于开发此类疾病的治疗策略。

 DESCRIPTION (provided by applicant): The formation of accumulated, abnormally folded proteins is associated with more than twenty different clinical syndromes, each of which is associated with a distinct `misfolding' protein. These misfolded proteins aggregate and form the hallmarks of many neurodegenerative diseases, termed amyloids. Amyloid formation is associated with neurodegenerative disseases such as Alzheimer's, Parkinson's, and Huntington's disease, as well as localized diseases such as Type II Diabetes. Of the amyloid-related diseases, polyglutamine (polyQ) diseases represent a set of heritable neurological disorders, comprising at least nine diseases. In polyQ diseases like Huntington's disease (HD), our knowledge of how and why an expanded tract of polyQ leads to aggregation and amyloid formation is largely hampered by the fact that there is little high-resolution structural and dynamic insight into this process. Furthermore, the ability of a polyQ protein misfolded species to engage in aberrant protein interactions has become increasingly studied. Particularly, the interactions of polyQ proteins with molecular chaperones and their resistance to proteolysis are poorly understood. Challenges posed by polyQ proteins are manifold and, therefore, new biochemical and biophysical approaches developed to tackle such problems would greatly aid our understanding of polyQ diseases. To accomplish this goal, this application seeks to further investigate the aggregative properties of polyQ proteins at high-resolution, namely the N- terminal fragment of the huntingtin protein (implicated in the progression of HD), by using by nuclear magnetic resonance (NMR) spectroscopy. Newly developed NMR methods, such as dark-state exchange saturation transfer (DEST) and lifetime line broadening, offer the capability to achieve atomic resolution on the dynamic exchange occurring in the self-assembly of polyQ proteins, in addition to their interactions with molecular chaperones such as Hsp70 and Hsp40. While this proposal will focus on the development and application of new NMR methodologies to such challenging systems, the study will be extended for investigation using a variety of other biophysical techniques, including electron paramagnetic resonance (EPR), fluorescence spectroscopy, and calorimetry. The outcome of the proposed studies on amyloid formation by polyQ proteins will significantly advance our understanding of HD and other polyQ diseases, in general, by achieving structural and dynamic insights with atomic-level resolution and will aid in the development of therapeutic strategies for such diseases.