Mitochondrial Aconitase and Parkinson's Disease

线粒体乌头酸酶和帕金森病

基本信息

批准号：
6731235
负责人：
MANISHA N PATEL
金额：
$ 33.47万
依托单位：
UNIVERSITY OF COLORADO DENVER
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-12-01 至 2007-11-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The long-term goal of this proposal is to elucidate the mechanism by which mitochondrial oxidative stress produces dopaminergic neuronal death in Parkinson's Disease (PD). The precise mechanism by which mitochondrial oxidative stress, bioenergetic decline and iron overload arise and collaborate to produce age-related neuronal death in Parkinson's disease remains unclear. It is hypothesized that neuronal damage in Parkinson's disease results, in part from direct superoxide radical toxicity due to oxidative inactivation of mitochondrial aconitase. The hypothesis predicts that superoxide production, arising from Complex I inhibition or abnormal dopamine metabolism, inactivates [4Fe-4S]Z+-containing mitochondrial aconitase, resulting in loss of aconitase activity and release Fe z+ and H202. Posttranslational modification of this key TCA cycle enzyme can therefore result in an increased iron load, oxidant burden and bioenergetic decline. The presence of an iron responsive element (IRE) in the 5' untranslated region of the mitochondrial aconitase Mrna provides an additional mechanism for iron dysregulation in Parkinson's disease. The proposal will utilize human PD samples, animal models of PD (1-methyl-4-phenyl-l,2,3,6-tetrahydropyridine and 6-hydroxydopamine) and dopaminergic cell culture models in conjunction with a diversity of tools and techniques that include biochemical analyses, confocal microscopy, molecular biology and transgenic/knockout/aging mice. Specific Aim 1 will determine whether mitochondrial aconitase is inactivated in human and experimental Parkinson's disease. The influence of aging and chronic mitochondrial oxidative stress will be determined using mice deficient in MnSOD, a critical mitochondrial antioxidant. Specific Aim 2 will determine whether mitochondrial aconitase inactivation contributes to impaired iron homeostasis. Specific Aim 3 will determine whether scavenging mitochondrial superoxide using native or synthetic antioxidants (e.g. MnSOD transgenic mice or metalloporphyrins) protect against mitochondrial aconitase inactivation in a manner that correlates with decreased iron overload and neuronal death in experimental Parkinson's disease. Specific Aim 4 will determine the downstream consequences of mitochondrial aconitase inactivation in experimental Parkinson's disease. Specifically, regulation of brain mitochondrial aconitase synthesis by the 5' IRE in its mRNA, impact on the TCA cycle capacity and direct neurotoxicity of aconitase gene silencing will be examined. These studies can advance our understanding of the oxidative mechanisms of neuronal death in Parkinson's disease and suggest novel therapeutic strategies for rescuing neurons from age-related neurodegeneration. Additionally, this line of investigation may explain Parkinson's disease arising from genetic factors uncovered by aging as well as environmental factors.

描述（由申请人提供）：该提案的长期目标是阐明线粒体氧化应激在帕金森氏病（PD）中产生多巴胺能神经元死亡的机制。线粒体氧化应激，生物能下降和铁超负荷的确切机制尚不清楚，并合作产生与年龄有关的神经元死亡。假设帕金森氏病的神经元损害部分是由于线粒体刺激酶氧化失活而导致的直接超氧化物自由基毒性。该假设预测，由复杂的I抑制作用或异常多巴胺代谢引起的超氧化物产生使[4FE-4S] Z+含有含有Z+的线粒体刺激酶，从而导致腺苷酸酶活性的丧失和释放Fe Z+和H202。因此，该关键TCA循环酶的翻译后修饰会导致铁负荷，氧化剂负担和生物能下降。在线粒体腺苷酶mRNA的5'未翻译区域中存在铁反应元件（IRE），这为帕金森氏病中铁失调的附加机制提供了额外的机制。该提案将利用人类PD样品，PD（1-甲基-4-苯基-L，2,3,6-四氢吡啶和6-羟基多巴胺）的动物模型以及在包括生物学，汇总分析，分子的分子分析的工具和技术的多样性中，以及包括多样性的工具和技术结合的多巴胺能细胞培养模型老鼠。特定的目标1将确定在人和实验帕金森氏病中是否会使线粒体刺激酶失活。衰老和慢性线粒体氧化应激的影响将使用缺乏MNSOD的小鼠（一种临界线粒体抗氧化剂）确定。特定的目标2将确定线粒体刺激酶失活是否有助于铁稳态受损。具体目标3将确定使用天然或合成抗氧化剂（例如MNSOD转基因小鼠或金属核写蛋白）的清除线粒体超氧化物是否可以防止与线粒体刺激酶失活的方式，以与实验性帕金森病中的铁超载和神经元死亡相关的方式相关。具体目标4将确定实验性帕金森氏病中线粒体刺激酶失活的下游后果。具体而言，将检查5'ire在其mRNA中对脑线粒体刺激酶合成的调节，将检查对TCA循环能力的影响和腺苷酶基因沉默的直接神经毒性。这些研究可以提高我们对帕金森氏病神经元死亡的氧化机制的理解，并提出新的治疗策略，以从与年龄相关的神经变性中拯救神经元。此外，这种调查可能会解释帕金森氏病，这是由于衰老和环境因素发现的遗传因素引起的。