Identifying Drugs to Treat Age-Dependent Neurodegeneration

描述（申请人提供）：在正常衰老和许多神经退行性疾病的进展过程中，细胞损伤的积累会扰乱神经系统的正常功能，改变行为和记忆。越来越多的证据表明，高度保守的巨噬通路（autophagy）通过促进细胞损伤和蛋白质聚集物的大量清除，参与维持成熟的神经系统。最近，我们研究了自噬基因的衰老特征，发现该途径在老年果蝇中枢神经系统中被显著抑制。与此同时，包括不溶性泛素化蛋白（IUP）在内的细胞损伤标志物在老年果蝇大脑中显示出急剧增加。基因分析发现，关键基因的突变也会显著缩短成年人的寿命（35%至60%），并导致进行性神经缺陷，这些缺陷与阿尔茨海默氏症的专利有着惊人的相似之处。这两种表型都是加速衰老和神经元无法有效清除细胞损伤的迹象。更重要的是，我们最近观察到，上调或增强成人神经系统中该通路的限速成分水平，可以抑制正常年龄依赖性细胞损伤（IUP）的积累，并显着延长成年人近60%的寿命。总之，年龄依赖性表型的加速和抑制表明，成熟神经系统的建模变化可以在果蝇中有效地完成，以便更好地了解与衰老和进行性神经衰退有关的细胞因素。在本研究中，我们利用自噬的保守功能及其调控，并结合果蝇基因和转基因技术来鉴定增强自噬、促进成人寿命和神经功能的神经保护化合物。Aim 1的研究将使用GAL4/UAS系统在光感受器细胞或整个成人中枢神经系统中表达神经毒性肽。化合物将筛选其减少与其在神经组织和细胞中的表达相关的细胞毒性表型的能力。对于Aim 2，在Aim 1中鉴定的化合物和浓度范围将用于检查药物增强自噬和清除衰老的成年果蝇神经系统中自然发生的细胞损伤的能力。对于Aim 3，一旦一组选定的化合物被确定，它们将被用于长期衰老研究，以测试它们延长成年人寿命的能力。此外，由于果蝇强大的基因和短暂的寿命，独特的药物组合和治疗方案也可以快速设计和快速测试。该提案的总体目标是更好地理解清除途径在衰老中发挥的关键作用，并开发一种快速的体内方法来设计和测试可用于治疗人类神经系统疾病的药物。公共卫生相关性：阿尔茨海默病和其他与年龄有关的神经系统疾病影响着全世界数百万人。在这个时候，治疗选择是有限的，新的治疗化合物的表征需要开发新的方法来系统地测试药物疗效。本提案中概述的研究将在果蝇中开发快速的体内筛选技术，以检测与衰老和神经元损伤控制途径（如自噬）丧失相关的神经退行性表型的变化。

DESCRIPTION (provided by applicant): During normal aging and in the progression of many neurodegenerative disorders the accumulation of cellular damage can perturb the normal function of the nervous system and change behaviors and memory. A growing body of evidence shows that the highly conserved macroautophagy pathway (autophagy) is involved in maintaining the mature nervous system by facilitating the bulk removal of cellular damage and protein aggregates. Recently we have examined the aging profiles of autophagy genes and found the pathway is significantly suppressed in the older Drosophila CNS. At the same time, cellular damage markers including insoluble ubiquitinated proteins (IUP) show a dramatic increase in older fly brains. Genetic analysis identifies mutations in key genes that also significantly shorten adult lifespans (35 to 60%) and cause progressive neural defects that share striking similarities to those seen in Alzheimer's patents. Both phenotypes are signs of accelerated aging and an inability of neurons to clear cellular damage effectively. Of greater significance is our recent observation that upregulating or enhancing the level of rate-limiting components of the pathway in the adult nervous system suppresses the normal age- dependent accumulation of cellular damage (IUP) and significantly extends adult longevity nearly 60%. Taken together both the acceleration and suppression of age-dependent phenotypes shows that modeling changes to the mature nervous system can be done effectively in Drosophila, in order to gain a greater understanding of cellular factors involved with aging and progressive neural decline. In this proposal we take advantage of the conserved function of autophagy and its regulation, and coupled this information together with Drosophila genetic and transgenic techniques to identify neural protective compounds that enhance autophagy and promote adult longevity and neural function. Studies in Aim 1 will use the GAL4/UAS system to express neural toxic peptides in photoreceptor cells or throughout the adult CNS. Compounds will be screened for their ability to reduce cytotoxic phenotypes associated with their expression in neural tissues and cells. For Aim 2 compounds and concentration ranges identified in Aim 1 will be used to examine the ability of drugs to enhance autophagy and clear cellular damage that naturally occurs in aging adult Drosophila nervous system. For Aim 3 once a select set of compounds are identified they will be used in long-term aging studies to test their ability to extend adult lifespans. In addition, unique drug combinations and treatment regimes can also be quickly design and rapidly tested due to the powerful genetics and compressed lifespans of Drosophila. The overall goal of this proposal is to better understand the critical role that clearance pathways play in aging and to develop a rapid in vivo method to design and test drugs that can be used for the treatment of human neurological disorders. PUBLIC HEALTH RELEVANCE: Alzheimer's disease and other age-related neurological disorders affect millions of people worldwide. At this time treatment options are limited and characterization of new therapeutic compounds requires the development of novel methods to systematically test drug efficacy. The research outlined in this proposal will develop rapid in vivo screening techniques in Drosophila that detect changes in neural degenerative phenotypes associated with aging and loss of neuronal damage-control pathways like autophagy.