Gene-environment interactions in transgenic rat models of Parkinson disease

描述(由申请人提供)： (参见说明)：一般挑战领域15：翻译科学。挑战主题15-ES-101：环境暴露对使用非人类模型的表型结果的影响。单基因形式的帕金森病(PD)并不常见，约占所有病例的10%--纯环境因素引起的帕金森综合症也很少见。绝大多数帕金森病被认为是终身环境暴露叠加遗传易感性的结果，但这些基因-环境相互作用的性质尚不清楚。我们将研究临床上相关的杀虫剂鱼藤酮对帕金森病转基因大鼠模型表型结果的影响。虽然鱼藤酮已经被用来建立大鼠帕金森病的模型，但直到现在才有流行病学证据表明鱼藤酮是人类帕金森病的真正危险因素。PD的鱼藤酮模型受到其可变性的限制，但我们通过创建一种新的高度可重复性的模型克服了这一障碍。不幸的是，鱼藤酮模型在小鼠身上效果不佳，因此不可能使用转基因(转基因；TG)小鼠来检查这种杀虫剂与基因-环境的相互作用。尽管有许多PD的TG小鼠模型，但它们对发病机制的了解有限，通常不能再现人类疾病的关键行为或病理特征。此外，传统的转基因小鼠在技术上受到转基因插入部位的位置效应、有限的转基因大小/结构以及“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，它们不受插入位置的影响，并且可以受到其天然启动子的调节。具体地说，我们创造了过表达WT和突变的人α-突触核蛋白(AS)和突变的LRRK2的TG大鼠。WT AS基因的双重和三重表达增加导致帕金森病，而随着表达增加的启动子多态可能与发生‘散发性’或‘特发性’帕金森病的风险增加有关。LRRK2突变是常染色体显性遗传性帕金森病最常见的原因。在一些人群中，高达40%的个体携带LRRK2突变，但外显性是高度可变的。因此，一些LRRK2突变可能是帕金森病的危险因素，而不是本身的致病因素-环境暴露可能在疾病表达中发挥主要作用。随着这些新的大鼠模型的发展，我们现在可以研究鱼藤酮对TG动物的影响。这个项目代表了Greenamre实验室(鱼藤酮模型)和陈建丽实验室(TG大鼠模型)的合作，利用各种相关的行为、病理和生化结果，研究了一种已知的环境风险因素对帕金森病新遗传模型表型的影响。 与公共卫生相关：绝大多数帕金森病被认为是由于一生暴露在环境中，叠加在个人的复合遗传易感性上造成的，但这些基因-环境相互作用的性质尚不清楚。该项目将研究临床上相关的杀虫剂鱼藤酮对帕金森病转基因大鼠模型表型结果的影响。因此，我们将开始定义已知的环境风险因素和已确定的遗传风险因素之间的关系，这是造成这种毁灭性疾病的原因。

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.