Gene-environment interactions in transgenic rat models of Parkinson disease

描述（由申请人提供）： (See一般挑战领域15：转化科学（General Challenge Area 15：Translational Science）挑战主题15-ES-101：环境暴露对非人类模型表型结果的影响。单基因形式的帕金森病（PD）是不常见的，约占所有病例的10%-帕金森综合征的纯粹环境原因是罕见的。绝大多数PD被认为是由于一生的环境暴露叠加遗传易感性，但这些基因-环境相互作用的性质尚不清楚。我们将研究一种临床相关的杀虫剂鱼藤酮对PD转基因大鼠模型表型结果的影响。虽然鱼藤酮已被用于模拟大鼠PD的特征，但直到现在才有流行病学证据表明鱼藤酮是人类PD的真正危险因素。PD的鱼藤酮模型受到其可变性的限制，但我们通过创建一个新的高度可重复的模型克服了这一障碍。不幸的是，鱼藤酮模型在小鼠中不起作用，因此不可能使用遗传修饰（转基因; Tg）小鼠来检查与这种农药的基因-环境相互作用。尽管存在许多PD的Tg小鼠模型，但它们提供了对发病机制的有限见解，并且通常不能再现人类疾病的关键行为或病理特征。此外，常规的Tg小鼠在技术上受到转基因插入位点的位置效应、有限的转基因大小/结构和“人工”启动子的使用的限制。为了克服这一障碍，我们创造了BAC Tg大鼠，其与插入位点的位置效应绝缘，并且可以由其天然启动子调节。具体而言，我们已经创建了过表达WT和突变型人α-突触核蛋白（AS）和突变型LRRK 2的Tg大鼠。来自基因双拷贝和三拷贝的WT AS表达增加导致PD，并且增加AS表达的启动子多态性可能与发展“散发性”或“特发性”PD的风险增加相关。LRRK 2突变是常染色体显性PD的最常见原因。在某些人群中，高达40%的个体携带LRRK 2突变，但突变率高度可变。因此，一些LRRK 2突变可能是PD的风险因素，而不是病因本身-环境暴露可能在疾病表达中起主要作用。随着这些新的大鼠模型的发展，我们现在可以研究鱼藤酮在Tg动物中的作用。该项目代表Greenamyre实验室（鱼藤酮模型）和Chenjian Li实验室（Tg大鼠模型）之间的合作，使用各种相关的行为，病理和生化结果研究已知环境风险因素对PD新遗传模型表型的影响。 公共卫生相关性：绝大多数PD被认为是由于一生的环境暴露叠加在个体的复合遗传易感性上，但这些基因-环境相互作用的性质尚不清楚。本项目将研究一种临床相关农药鱼藤酮对PD转基因大鼠模型表型结果的影响。因此，我们将开始确定已知的环境风险因素和确定的遗传风险因素之间的关系，在这种毁灭性的疾病的原因。

DESCRIPTION (provided by applicant): (See instructions): General Challenge Area 15: Translational Science. Challenge Topic 15-ES-101: Effects of Environmental Exposures on Phenotypic Outcomes Using Non-Human Models. Monogenic forms of Parkinson disease (PD) are uncommon, accounting for about 10% of all cases - and purely environmental causes of parkinsonism are rare. The vast majority of PD is believed to result from a lifetime of environmental exposures superimposed on genetic susceptibility, but the nature of these gene- environment interactions is unclear. We will examine the effects of a clinically relevant pesticide, rotenone, on phenotypic outcomes in transgenic rat models of PD. While rotenone has been used to model features of PD in rats, only now is there epidemiological evidence indicating that rotenone is a bona fide risk factor for human PD. The rotenone model of PD has been limited by its variability, but we have overcome this barrier by creating a new highly reproducible model. Unfortunately, the rotenone model does not work well in mice, so it has been impossible to use genetically modified (transgenic; Tg) mice to examine gene- environment interactions with this pesticide. Although there are many Tg mouse models of PD, they have provided somewhat limited insights into pathogenesis, and generally do not reproduce key behavioral or pathological features of the human disease. Moreover, conventional Tg mice are limited technically by positional effects of the transgene insertion site, by limited transgene size/structure, and by use of 'artificial' promoters. To overcome this barrier, we have created BAC Tg rats that are insulated from positional effects of insertion site, and which can be regulated by their native promoters. Specifically, we have created Tg rats that overexpress WT and mutant human alpha-synuclein (AS) and mutant LRRK2. Increased expression of WT AS from gene dupli- & triplications causes PD, and promoter polymorphisms that increase AS expression may be associated with increased risk of developing 'sporadic' or 'idiopathic' PD. LRRK2 mutations are the most common cause of autosomal dominant PD. In some populations, up to 40% of individuals carry LRRK2 mutations, but penetrance is highly variable. As such, some LRRK2 mutations may be risk factors for PD rather than causative per se - and environmental exposures may play a major role in disease expression. With the development of these new rat models, we can now study rotenone effects in Tg animals. This project represents a collaboration between the Greenamyre lab (rotenone model) and the Chenjian Li lab (Tg rat models) to study the effects of a known environmental risk factor on the phenotype of novel genetic models of PD using a variety of relevant behavioral, pathological and biochemical outcomes. PUBLIC HEALTH RELEVANCE: The vast majority of PD is believed to result from a lifetime of environmental exposures superimposed on an individual's composite genetic susceptibility, but the nature of these gene-environment interactions is unclear. This project will examine the effects of a clinically relevant pesticide, rotenone, on phenotypic outcomes in transgenic rat models of PD. As such, we will begin to define the relationship between a known environmental risk factor and identified genetic risk factors in the causation of this devastating illness.