High Throughput Screening for Small-molecules Facilitating Prion Study

产品说明：传染性海绵状脑病（Transmissible spongiform encephalopathies，TSE），又称朊病毒病，是一组罕见的哺乳动物传染性神经退行性疾病。TSE的病原体被认为是正常功能宿主细胞蛋白（PrPC）的错误折叠形式（PrPSc）。部分由于基于蛋白质的病理学的并发症，TSE仍然无法治愈，目前没有治疗方法可以阻止其快速进展。有趣的是，芽殖酵母（Saccharomyces cerevisiae）含有几种非孟德尔遗传元件，这些元件以改变的蛋白质构象形式传播，被称为酵母朊病毒。它的简单性和遗传可追踪性使酵母成为朊病毒研究的一个强有力的模式生物。在这项提案中，我们计划使用酵母朊病毒[SWI+]系统作为一个平台，以确定小分子，可以通过高通量筛选方法抑制朊病毒的繁殖。[SWI+]是本实验室发现的，其蛋白质决定簇是Swi 1，是一种进化上保守的染色质重塑复合物SWI/SNF的亚基。我们发现，FLO 1的表达，SWI/SNF的目标基因编码酵母丝状生长所需的细胞壁蛋白被严重抑制[SWI+]。通过用URA 3编码区替换FLO 1-ORF，我们创建了一个忠实的基于FLO 1启动子-URA 3的染色体报告基因。虽然[SWI+]不能在缺乏尿嘧啶的培养基中生长，但同基因非朊病毒细胞可以。因此，可以消除[SWI+]的化合物可以在缺乏尿嘧啶的培养基中在简单、安全的生长测定中被阳性选择。我们证明，这种具有成本效益的测定是适合于在384孔格式的高通量筛选。我们的试点筛选已经产生了一些命中（可以有效消除[SWI+]的化合物）。我们预期，从本研究中获得的一些抗朊病毒化合物将可能成为朊病毒研究的有价值的分子探针，并且对其朊病毒治疗机制的进一步研究将导致鉴定对朊病毒化重要的新型细胞组分和开发TSE治疗迫切需要的有效抗朊病毒治疗药物。由于[SWI+]朊病毒的淀粉样蛋白性质，我们还期望一些鉴定的抗朊病毒化合物也有效抑制由蛋白质错误折叠引起的非朊病毒淀粉样蛋白生成性疾病，例如阿尔茨海默病（AD）、帕金森病（PD）和肌萎缩性侧索硬化症（ALS）。

DESCRIPTION: Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are a group of unusual infectious mammalian neurodegenerative disorders. The pathogen of TSEs is believed to be a misfolded form (PrPSc) of a normal functional host cellular protein (PrPC). Partly due to the complication of protein-based pathology, TSEs remain incurable and currently there is no treatment that can halt their rapid progression. Intriguingly, the budding yeast, Saccharomyces cerevisiae, contains several non-Mendelian genetic elements that are transmitted as altered protein conformations and are termed as yeast prions. Its simplicity and genetic trackability has made yeast a powerful model organism for prion research. In this proposal, we plan to use the yeast prion [SWI+] system as a platform to identify small molecules that can inhibit prion propagation through a high-throughput screen approach. [SWI+] was discovered in our laboratory, whose protein determinant is Swi1, a subunit of an evolutionarily conserved chromatin-remodeling complex - SWI/SNF. We found that the expression of FLO1, a SWI/SNF target gene encoding a cell wall protein required for yeast filamentous growth is severely suppressed by [SWI+]. By replacing the FLO1-ORF with the URA3-coding region, we created a faithful FLO1promoter-URA3-based chromosomal reporter. While [SWI+] cannot grow in media lacking uracil, the isogenic non-prion cells can. Thus, chemical compounds that can eliminate [SWI+] can be positively selected in a simple, safe growth assay in media lacking uracil. We demonstrate that this cost-effective assay is suitable for high-throughput screens in a 384-well format. Our pilot screens have already yielded a number of hits (chemical compounds that can effectively eliminate [SWI+]). We anticipate that some anti-prion compounds obtained from this study will likely become valuable molecular probes for prion research and further investigation of their prion- curing mechanism will lead to identification of novel cellular components important for prionization and development of effective anti-prion therapeutic drugs that are urgently needed for TSE treatment. Due to the amyloid nature of the [SWI+] prion, we also expect that some identified anti-prion compounds are also effective in suppressing non-prion amyloidogenic diseases resulted from protein misfolding, such as Alzheimer's disease (AD), Parkinson disease (PD), and amyotrophic lateral sclerosis (ALS).