Altered transport and epigenomic changes in maneb-potentiated neurotoxicity

摘要 反复暴露于环境因素，如杀虫剂和金属，可以改变基因表达 模式，潜在地导致对未来的毒性损伤的增强的易感性。超过90%的 帕金森病（PD）病例被认为是特发性的，流行病学表明参与 PD中的杀虫剂具体而言，暴露于除草剂百草枯（PQ）和杀真菌剂代森锰（MB）是 与PD风险增加75-80%相关。此外，基因表达的表观基因组变化是 被认为在神经退行性疾病如PD中起作用。我以前的NIEHS资助的研究（F32 ES 019821）证明，MB增强PQ神经毒性不仅仅是由于氧化增强 应力，但一个复杂的机制，涉及巯基修饰MB和氧化PQ。另外的基因 表达数据显示，与PQ相比，MB显著改变了更多基因的表达。MB 诱导4种氨基酸转运蛋白和2种金属转运蛋白。特别感兴趣的是，Ala-、Ser-、Cys- 优选转运蛋白-1（ASCT-1（Slc 1a 4））和质子偶联的二价金属离子转运蛋白（LSH（Slc 11 a1）） 与对照相比，MB和PQ+MB诱导的细胞数量增加2倍以上。对此的工作假设是 K99/R 00职业发展奖的建议是，长期接触甲基溴可增强PQ介导的 修饰氨基酸引起的PQ摄取增加引起的多巴胺能神经元变性 转运蛋白表达、金属介导的氧化应激和表观基因组的变化。为了实现这一点，4 将使用由体外和体内模型组成的特定目标（2个指导，2个独立）。在特定 目的1（K99指导阶段），将采用体外和体内模型来确定是否增强 PQ神经毒性是由于MB介导的ASCT-1和LSH诱导。具体目标2（K99辅导阶段） 将研究与多巴胺代谢相关的基因甲基化是否在机制上参与MB- 增强PQ神经毒性。具体目标3（R 00独立阶段）中提出的研究将探索 组蛋白H3甲基化和乙酰化的改变引起的长期农药暴露。最后，具体 目的4（R 00独立期）将研究DNA甲基化组响应于长时间的DNA甲基化的整体改变。 农药暴露术语。这个项目的目的是进一步发展我的研究计划，并实现战略 NIEHS的目标是通过表观基因组学研究将环境影响与疾病联系起来， 培养下一代环境科学家拟议的研究将满足这些目标， 促进我独立研究事业的发展。

Abstract Repeated exposure to environmental agents, such as pesticides and metals, can alter gene expression patterns, potentially resulting in enhanced susceptibility to future toxic insults. With greater than 90% of Parkinson's disease (PD) cases considered idiopathic, epidemiology has indicated the involvement of pesticides in PD. Specifically, exposures to the herbicide paraquat (PQ) and the fungicide maneb (MB) are associated with a 75-80% increased risk of PD. Additionally, epigenomic changes in gene expression are postulated to play a role in neurodegenerative disorders like PD. My previous NIEHS funded research (F32 ES019821) demonstrated that MB-potentiation of PQ neurotoxicity was not simply due to enhanced oxidative stress, but a complex mechanism involving thiol-modification by MB and oxidation by PQ. Additional gene expression data show that MB significantly altered the expression of more genes compared to PQ. MB induced 4 different amino acid transporters and 2 metal transporters. Of particular interest, Ala-, Ser-, Cys- preferring transporter-1 (ASCT-1 (Slc1a4)) and proton coupled, divalent metal ion transporter (LSH (Slc11a1)) were induced greater than 2-fold by MB and PQ+MB compared to control. The working hypothesis for this K99/R00 Career Development Award proposal is that long-term exposure to MB potentiates PQ-mediated neurodegeneration of dopaminergic neurons caused by increased uptake of PQ due to modified amino acid transporter expression, metal-mediated oxidative stress and changes in the epigenome. To accomplish this, 4 specific aims (2 mentored, 2 independent) consisting of in vitro and in vivo models will be used. In Specific Aim 1 (K99 mentored phase), both in vitro and in vivo models will be employed to determine if potentiation of PQ neurotoxicity is due to MB-mediated induction of ASCT-1 and LSH. Specific Aim 2 (K99 mentored phase) will study if methylation of genes associated with dopamine metabolism is mechanistically involved in MB- potentiated PQ neurotoxicity. Research proposed in Specific Aim 3 (R00 independent phase) will explore alterations in histone H3 methylation and acetylation caused by long term pesticide exposure. Lastly, Specific Aim 4 (R00 independent phase) will investigate global alterations in the DNA methylome in response to long term pesticide exposure. This project is designed to further develop my research program and fulfill strategic goals of the NIEHS by connecting environmental influences to disease through the study of epigenomics and to train the next generation of environmental scientists. The proposed research will meet these goals and foster the development of my independent research career.