MANIPULATION OF POLYGLUTAMINE-PROTEIN INTERACTIONS

具有扩展的聚谷氨酰胺结构域的蛋白质导致八种遗传性神经退行性疾病，包括亨廷顿舞蹈病（HD）。这些疾病主要影响运动控制系统，其中一些与精神症状和/或痴呆有关。这些疾病不断恶化，最终导致死亡，但目前还没有治疗方法。聚谷氨酰胺结构域的长度决定了疾病发病的年龄和疾病表型，但致病的分子机制尚不清楚。单克隆抗体可以选择性地识别具有扩展重复序列的聚谷氨酰胺结构域蛋白，并且扩展重复序列蛋白显示出独特的蛋白质相互作用，表明它们采用新的构象。新的构象被假设导致独特的致病蛋白相互作用，导致神经元死亡和聚集，这是这些疾病的标志。干扰异常的聚谷氨酰胺蛋白相互作用可能干扰疾病的发病机制，因此在治疗上是有用的。聚谷氨酰胺-蛋白相互作用的机制尚不清楚。在本应用中，聚谷氨酰胺-蛋白相互作用将通过一种新的体外系统、组织培养、脑切片和转基因动物来表征。通过筛选组合肽库来鉴定聚谷氨酰胺结合肽。这些肽在体外和细胞中抑制聚集，将用于确定与扩展的聚谷氨酰胺结构域结合的序列要求，并优化相互作用的抑制。优化的聚谷氨酰胺结合肽对细胞聚集和细胞死亡的影响将在转染细胞和转染脑切片等模型系统中进行研究。将产生表达谷氨酰胺结合肽的转基因小鼠，并与表达谷氨酰胺疾病的小鼠交配，以确定对症状发展和发病机制的影响。

Proteins with expanded polyglutamine domains cause eight inherited neurodegenerative diseases, including Huntington's disease (HD). These disorders primarily effect the motor control systems and some are associated with psychiatric symptoms and/or dementia. The diseases are relentlessly progressive and ultimately lead to death, but no treatments exist. The length of the polyglutamine domain determines the age of disease onset and disease phenotype, but the molecular mechanism(s) responsible for pathogenesis are unknown. Monoclonal antibodies are available that selectively recognize polyglutamine domain proteins with expanded repeats and the expanded repeat proteins display unique protein interactions indicating that they adopt a novel conformation. The novel conformation is hypothesized to result in unique pathogenic protein interactions that cause neuronal death and aggregation, which are hallmarks of these diseases. Perturbing abnormal polyglutamine protein interactions may interfere with disease pathogenesis and, therefore, be therapeutically useful. Mechanisms of polyglutamine-protein interaction are poorly understood. In this application, polyglutamine-protein interactions will be characterized using a novel in vitro system, tissue culture, brain slices and transgenic animals. Polyglutamine-binding peptides have been identified by screening a combinatorial peptide library. These peptides inhibit aggregation in vitro and in cells will be used to determine the sequence requirements for binding to an expanded polyglutamine domain and to optimize inhibition of interaction. The effect of optimized polyglutamine-binding peptides on aggregation and cell death will be studied in model systems such as transfected cells and transfected brain slices. Polyglutamine-binding peptide expressing transgenic mice will be generated and mated to polyglutamine disease expressing mice to determine the effect on symptom development and pathogenesis.