Investigation of mechanism of action of drug induced agranulocytosis.

描述（由申请人提供）：亨廷顿病（HD）是一种毁灭性的神经退行性疾病，由亨廷顿蛋白（Htt）中聚谷氨酰胺束扩大引起，导致其聚集成富含-片的原纤维。有证据表明，Htt的17个氨基酸头饰（N17）强烈调节其聚集。这项研究的一个目标是预测N17；S的结构及其在寡聚化中的作用，通过分子动力学模拟，并进行实验验证。另一个目标是利用这些结构信息和实验数据来设计Htt聚集的抑制剂。更好地了解Htt蛋白聚集的早期结构对于设计亨廷顿病的治疗方法是非常宝贵的。具体目标是：1。探讨N17头在亨廷顿蛋白聚集中的结构作用。！ 先前对孤立N17头盔的MD模拟表明，它是高度螺旋的，并采用由一个和两个两向螺旋组成的两个高度密集的构象。我们将：a.使用马尔可夫状态模型在Folding@home上进行N17-polyQ聚集的分子动力学模拟。我们将研究我们的假设，即多个N17疏水表面的埋藏通过正确地相互定位来启动多q束的聚集。基于模拟，N17中的突变将被提出，有望抑制Htt聚集。b.通过与斯坦福大学Judith Frydman实验室的合作，将通过实验验证计算预测的破坏聚集的N17突变。通过模拟N17头戴的结构，计算设计和模拟肽聚集抑制剂，并通过实验验证有前景的抑制肽。！ 我将设计抗Htt聚集的“钉状肽”抑制剂，特别是通过调节N17<s在寡聚化过程中的假设作用。“钉钉肽”是哈佛大学Greg Verdine实验室最近首创的一项技术，它将肽钉成螺旋状构象。我们将：a.使用“钉定肽”来测试关于亨廷顿蛋白寡聚物结构的假设。钉接肽将被设计成模拟上述MD模拟中聚集核中N17的螺旋结构，并将用钉接肽重新运行模拟。b.设计亨廷顿蛋白聚集的钉接肽抑制剂，通过引入实验显示的N17突变来阻断聚集，同时保持N17区域之间的结合界面。c.有前途的肽将由弗里德曼实验室获得并在体外和体内进行实验测试。“钉接肽”在抑制Htt聚集方面具有潜在的“纳米药物治疗”应用前景。

DESCRIPTION (provided by applicant): Huntington<s Disease (HD) is a devastating neurodegenerative disease caused by an expanded polyglutamine tract in the huntingtin (Htt) protein, leading to its aggregation into beta-sheet-rich fibrils. Evidence suggests the 17 amino acid headpiece (N17) of Htt strongly modulates its aggregation. One goal of this research is to predict N17;s structure and role in oligomerization via molecular dynamics simulations, with experimental verification. Another goal is to leverage this structural information and experimental data to design inhibitors of Htt aggregation. Better structural understanding of the early steps of aggregation of the Htt protein would be invaluable for designing therapeutics for Huntington<s Disease. The specific aims are: 1. To investigate the structural role of the N17 headpiece in huntingtin aggregation. ! Previous MD simulations of the isolated N17 headpiece suggest that it is highly helical, and adopts two highly populated conformations consisting of one and two amphipathic helices. We will: a. Perform molecular dynamics simulations of N17-polyQ aggregation on Folding@home using Markov state models. We will investigate our hypothesis that burial of multiple N17 hydrophobic surfaces initiates aggregation of the polyQ tracts by positioning them correctly relative to each other. Based on the simulations, mutations in N17 will be proposed that would be expected to inhibit Htt aggregation. b. N17 mutations computationally predicted to disrupt aggregation will be experimentally verified, via a collaboration with Judith Frydman<s lab at Stanford. 2. To computationally design and simulate peptide inhibitors of aggregation by mimicking the structure adopted by the N17 headpiece, and verify promising inhibitory peptides experimentally. ! I will design "stapled peptide" inhibitors against Htt aggregation, specifically by modulating N17<s hypothesized role in the oligomerization process. "Stapled peptides", a recent technique pioneered by Greg Verdine<s lab at Harvard, "staples" peptides into an alpha-helical conformation. We will: a. Use "stapled peptides" to test hypotheses about the huntingtin oligomeric structure. Stapled peptides will be designed to mimic the proposed helical structure(s) of N17 in the aggregation nucleus in the MD simulations above, and simulations will be re-run with the stapled peptides. b. Design stapled peptide inhibitors of huntingtin aggregation, by incorporating N17 mutations shown experimentally to block aggregation, while maintaining the binding interface between N17 regions. c. Promising peptides will be procured and experimentally tested both in vitro and in vivo by the Frydman Lab. "Stapled peptides" have potential applications as "nanomedicine therapeutics" in inhibiting Htt aggregation. PUBLIC HEALTH RELEVANCE: Lay description:! ! Huntington<s Disease is a devastating neurodegenerative disease caused by misfolding and aggregation of the huntingtin protein. Evidence suggests the first 17 amino acids (N17) of the huntingtin protein strongly stimulate its aggregation. The goals of this research are to predict N17<s structure and role in this aggregation process computationally, with experimental verification, and then to leverage this structural information and experimental data to design and test inhibitors of huntingtin aggregation.