The Interaction of parkin and environmental toxins in Parkinson’s disease

摘要 许多环境和遗传因素是帕金森病黑质DA神经元变性的基础 疾病(PD)。接触农药如鱼藤酮和有机氯除草剂如2，4-D，一种主要的 越战中使用的橙剂成分与帕金森病的发病率较高有关。黑质DA 神经元有大量的轴突分支，特别容易受到微管解聚剂的影响。 以往的研究表明，许多环境中的钯毒素对微管有影响。我们之前在 体外和大鼠神经元培养表明，parkin结合并稳定微管。在我们的 正常人和帕金森病患者IPSC来源的中脑DA神经元的初步研究 突变，我们发现parkin突变显著降低了神经元的总长度和复杂性。 通过破坏微管的稳定性。此外，环境中的钯毒素，如2，4-D，有很多 Parkin基因突变帕金森病患者中脑DA神经元毒性高于正常 控制。为了证明这些表型确实是由parkin引起的，我们将产生等基因的ipsc 通过修复帕金森病患者ipscs中的parkin突变和在对照中引入导致帕金森病的parkin突变 IPSCs。这些等基因的IPSCs将被用来检测PD环境毒素对人类的影响 中脑DA神经元的体外培养和大鼠脑内。该提案旨在研究帕金和环境PD如何 毒素影响一个共同的分子靶点-微管-影响中脑多巴胺能神经元的生存 来自同基因的IPSCs对的神经元。单个人黑质DA神经元的独特形态， 由于其约4.6米长的轴突树枝，使细胞特别容易受到遗传(例如， 导致微管不稳定的环境因素(如鱼藤酮、2，4-D)。机械论 从帕金的保护作用的研究中获得的见解将有助于识别 帕金森病的疾病修正疗法。

Abstract Many environmental and genetic factors underlie the degeneration of nigral DA neurons in Parkinson's disease (PD). Exposure to pesticides such as rotenone and organochlorine herbicides such as 2,4-D, a major component of Agent Orange used in Vietnam War, has been linked to higher incidence of PD. Nigral DA neurons have massive axon arborization and are particularly vulnerable to microtubule-depolymerizing agents. Previous studies show that many environmental PD toxins impact on microtubules. Our previous studies in vitro and in rat neuronal cultures have shown that parkin binds to and stabilizes microtubules. In our preliminary studies using iPSC-derived midbrain DA neurons from normal subjects and PD patients with parkin mutations, we found that parkin mutations markedly reduced the total length and complexity of neuronal processes by destabilizing microtubules. Furthermore, environmental PD toxins, such as 2,4-D, had much higher toxicity on midbrain DA neurons from PD patients with parkin mutations than those from normal controls. To demonstrate that these phenotypes are indeed caused by parkin, we will generate isogenic iPSC by repairing parkin mutations in PD patient iPSCs and by introducing PD-causing parkin mutations in control iPSCs. These lines of isogenic iPSCs will be used to examine the impact of PD environmental toxins on human midbrain DA neurons in vitro and in rat brains. The proposal aims to study how parkin and environmental PD toxins impact on a common molecular target – microtubules – to affect the survival of midbrain dopaminergic neurons derived from isogenic pairs of iPSCs. The unique morphology of a single human nigral DA neuron, with its estimated 4.6 meter long axon arborization, renders the cell particularly vulnerable to genetic (e.g. parkin mutations) or environmental factors (e.g. rotenone, 2,4-D) that destabilize microtubules. Mechanistic insights gained from the study on the protective effects of parkin would be useful for the identification of disease-modifying therapies for PD.