Influence of genetic variation on manganese neurotoxicity and Parkinson's disease

描述(由申请人提供) 该候选人的研究目标是在环境暴露和神经变性发病机制的背景下，研究锰(Mn)诱导的转运和神经毒性。帕金森氏症是一种神经退行性疾病，影响全球400万人，其中包括北美的100万人。长期接触锰会导致神经行为障碍，类似于帕金森氏症。大脑中的锰积累是帕金森氏症的已知风险因素。尽管人们越来越意识到与锰接触有关的问题，但对其潜在机制知之甚少。从体外研究中积累的证据表明，铁转运蛋白(FPN)，一种已知的铁出口因子，在 在锰的运输中。候选人的初步研究直接支持这一模式。她发现，缺乏FPN的Flatiron小鼠的肠道吸收较低，胆汁中锰的排泄减少。她的体外外源表达研究表明，野生型FPN阻止了锰的积累和细胞毒性，而熨斗突变FPN(H32R)完全取消了这种细胞保护作用。然而，FPN缺乏如何影响神经毒性和神经退行性变尚不清楚。基于研究人员的体外和动物模型研究，候选假说是FPN功能的丧失会促进脑内锰的积累，从而导致锰的神经毒性。已知的人类FPN突变会导致铁门蛋白病，这是一种遗传性血色素沉着症。候选人假设的一个推论是，携带FPN突变的个体更容易受到与锰接触相关的神经毒性和神经退行性疾病的影响。为了验证这些假设，候选人将结合使用多巴胺能SH-SY5Y细胞、熨斗小鼠和帕金森氏症患者。 在K99指导阶段，在哈佛大学公共卫生学院Wessling-Resnick博士的指导下，候选人将检验FPN在大脑中作为锰转运体的主要假设，以及FPN功能的丧失会增加大脑中的锰积累和神经毒性。指导阶段将提供培训，并为在独立阶段探索这一假设的人类后果奠定实验基础。其具体目的是：1)研究FPN在体内脑内锰转运中的作用。2)研究锰暴露对小鼠的神经毒性作用。候选人的长期职业目标是在一家学术机构获得终身教职，在那里她将成为ABL，以扩大她的研究领域，培训和指导研究生和本科生，并与她的学术同行合作并向他们学习。利用在指导阶段获得的培训和结果，她将检验FPN缺乏会增强MN神经毒性的假设，从而FPN突变的个体更容易患上神经退行性疾病。其具体目的是：3)确定已知的人类FPN突变对体外锰神经毒性的影响。4)探讨FPN基因变异与帕金森病的关系。

DESCRIPTION (provided by applicant) The candidate's research goals are to investigate manganese (Mn)-induced transport and neurotoxicity in the context of environmental exposure and pathogenesis of neurodegeneration. Parkinson's disease is a neurodegenerative disorder affecting four million people worldwide, including one million people in North America. Chronic exposure to Mn results in neurobehavioral deficits similar to Parkinson's disease. Mn accumulation in the brain is a known risk factor for Parkinson's disease. Despite growing awareness of the problems associated with Mn exposure, little is known about the underlying mechanisms. Accumulating evidence from in vitro studies suggests that ferroportin (Fpn), a known iron exporter, plays a role in Mn transport. The candidate's preliminary studies directly support this model. She found that flatiron mice, which are deficient in Fpn, have lower intestinal absorption and reduced biliary excretion of Mn. Her in vitro exogenous expression studies show that wild-type Fpn prevents Mn accumulation and cytotoxicity while the flatiron mutation Fpn (H32R) completely abrogates this cytoprotective effect. However, how Fpn deficiency influences neurotoxicity and neurodegeneration is not understood. Based on the investigators' in vitro and animal model studies, the candidate hypothesize that loss of Fpn function enhances brain Mn accumulation leading to Mn neurotoxicity. Known human mutations in Fpn cause ferroportin disease, an inherited form of hemochromatosis. A corollary to the candidate's hypothesis is that individuals with Fpn mutations are more vulnerable to neurotoxicity and neurodegenerative diseases associated with Mn exposure. To test these hypotheses, the candidate will combine the use of dopaminergic SH-SY5Y cells, flatiron mice, and human subjects with Parkinson's disease. During the K99 mentored phase, under the mentorship of Dr. Wessling-Resnick at Harvard School of Public Health, the candidate will test the major hypothesis that Fpn functions as a Mn transporter in the brain and that loss of Fpn function enhances brain Mn accumulation and neurotoxicity. The Mentored Phase will provide training and establish the experimental foundation to explore the human consequences of this hypothesis during the Independent Phase. The specific aims are: 1) To examine the role of Fpn in brain Mn transport in vivo. 2) To characterize Mn neurotoxicity in flatiron mice after exposure. The candidate's long-term career goal is to obtain a tenure- track faculty position at an academic institution where she will be abl to expand her area of research, train and instruct graduate and undergraduate students, and collaborate with and learn from her academic peers. Utilizing the training and results obtained during the mentored phase, she will test the hypothesis that Fpn deficiency enhances Mn neurotoxicity such that individuals with mutations in Fpn are more vulnerable to neurodegenerative diseases. The specific aims are: 3) To determine the effects of known human Fpn mutations on Mn neurotoxicity in vitro. 4) To explore the associations between Fpn gene variants and Parkinson's disease.