DJ-1 and neurodegeneration: its roles in mitochondria and in protein misfolding

DJ-1 和神经变性：其在线粒体和蛋白质错误折叠中的作用

• 批准号: MR/L003503/1
• 负责人: Flaviano Giorgini
• 金额: $ 58.63万
• 依托单位: University of Leicester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FL003503%2F1
• 关键词: DJ; neurodegeneration; its; roles; mitochondria

Parkinson's disease (PD), the second most common neurodegenerative disorder after Alzheimer's disease, is characterized by loss of dopaminergic neurons and the accumulation of misfolded alpha-synuclein in the form of Lewy bodies. The clinical symptoms include muscle rigidity, resting tremor, bradykinesia and postural instability as a result of the loss of dopaminergic neurons in the substantia nigra pars compacta. At later stages, the etiology of neuronal loss in sporadic PD is unknown, although aberrant alpha-synuclein aggregation and oxidative stress may contribute to the death of specific neuronal populations. Although little is known about the pathogenesis of PD, the detailed study of several genes associated with familial PD is enhancing the understanding of the molecular mechanisms associated with the disease. Mutations in one of these genes - PARK7 - accounts for ~1-2% of the sporadic cases of early onset recessive PD. PARK7 encodes for DJ-1, a small conserved protein which is broadly expressed and primarily localized to the cytoplasm, but also found in the nucleus and associated with mitochondria. Despite the importance of this protein, the role of DJ-1 in in formation of PD remains unclear. Several functions have been suggested for DJ-1, including an oxidative stress sensor, a chaperone which deals with misfolded protein in the cells, and a regulator of mitochondrial function. In this project we seek to clarify how DJ-1 contributes to mitochondrial function and protein misfolding, and ultimately how defects in these cellular processes due to DJ-1 mutations contribute to pathogenesis in PD. For these studies we plan to implement immortalized cell lines, primary cells from mice, as well as fruit flies. In preliminary experiments we have observed that mutations in DJ-1 alter its ability to localize to mitochondria in mammalian cells under oxidative stress conditions. We thus now seek to further characterize this effect with varied oxidants, and also in the context of alpha-synuclein overexpression. In addition, we plan to investigate the impact of these mutants on both morphology and function of mitochondria in mouse cells, as well as the effects on mitochondrial gene expression. Finally we plan to extend this approach by studying the effect of DJ-1 mutants on the structure and function of mitochondria in fruit flies. Next we seek to further explore the role of DJ-1 in protein misfolding by investigating the relationship between DJ-1 and the Tau protein, which has been implicated in several neurodegenerative disorders. The Tau protein is involved in the pathogenesis of Alzheimer's disease and is a major component of neurofibrillary tangles present in this disorder. The gene encoding Tau has recently been genetically linked to PD. In addition, DJ-1 co-localizes with Tau inclusions in Alzheimer's disease and other brain disorders. However any possible physical/functional interactions between DJ-1 and Tau have not been studied and their relationship in the context of PD has not been explored. Thus we propose to study the interaction between DJ-1 and Tau in living mammalian cells, and to what extent, if any, this alters Tau toxicity or formation of fibers. Furthermore, we plan to extend this work to a fruit fly model of Tauopathies, to ascertain whether DJ-1 modulates disease-relevant "symptoms" in these animals. In preliminary work we have observed that DJ-1 and Tau directly interaction when expressed in mammalian cells. Thus, our work will better define the role of DJ-1 in mitochondrial function and in protein misfolding which will help clarify its pathogenic role in PD. This added insight into DJ-1 biology may ultimately help inform therapeutic strategies for this, and other, neurodegenerative disorders.

帕金森病是仅次于阿尔茨海默病的第二种常见的神经退行性疾病，其特征是多巴胺能神经元的丢失和以路易小体的形式错误折叠的α-突触核蛋白的积聚。临床症状包括肌肉僵硬、静止性震颤、运动迟缓和姿势不稳，这是由于黑质致密部多巴胺能神经元丢失所致。在后期阶段，散发性帕金森病的神经元丢失的病因尚不清楚，尽管异常的α-突触核蛋白聚集和氧化应激可能导致特定神经元群体的死亡。尽管人们对帕金森病的发病机制知之甚少，但对几个与家族性帕金森病相关的基因的详细研究正在加深对与该病相关的分子机制的理解。其中一个基因Park7的突变约占早发性隐性帕金森病散发性病例的1-2%。Park7编码DJ-1，这是一种小的保守蛋白，广泛表达，主要定位于细胞质，但也存在于细胞核中，与线粒体有关。尽管该蛋白很重要，但DJ-1在帕金森病形成中的作用尚不清楚。已经提出了DJ-1的几个功能，包括氧化应激传感器，处理细胞中错误折叠的蛋白质的伴侣，以及线粒体功能的调节器。在这个项目中，我们试图阐明DJ-1是如何参与线粒体功能和蛋白质错误折叠的，以及最终DJ-1突变导致的这些细胞过程中的缺陷是如何在PD的发病机制中起作用的。对于这些研究，我们计划实施永生化细胞系，来自小鼠的原代细胞，以及果蝇。在初步实验中，我们观察到在氧化应激条件下，DJ-1的突变改变了其定位于哺乳动物细胞线粒体的能力。因此，我们现在寻求用不同的氧化剂以及在α-突触核蛋白过度表达的背景下进一步表征这种效应。此外，我们计划研究这些突变体对小鼠细胞线粒体形态和功能的影响，以及对线粒体基因表达的影响。最后，我们计划通过研究DJ-1突变体对果蝇线粒体结构和功能的影响来扩展这种方法。接下来，我们试图通过研究DJ-1和Tau蛋白的关系来进一步探索DJ-1在蛋白质错误折叠中的作用，Tau蛋白与几种神经退行性疾病有关。Tau蛋白参与了阿尔茨海默病的发病机制，是这种疾病中神经原纤维缠结的主要成分。编码Tau的基因最近被认为与帕金森病有关。此外，DJ-1与Tau包涵体在阿尔茨海默病和其他大脑疾病中共同定位。然而，尚未研究DJ-1和Tau之间任何可能的物理/功能相互作用，也没有探讨它们在帕金森病背景下的关系。因此，我们建议研究DJ-1和Tau在活的哺乳动物细胞中的相互作用，以及这在多大程度上改变了Tau的毒性或纤维的形成。此外，我们计划将这项工作扩展到牛磺酸病的果蝇模型，以确定DJ-1是否调节这些动物的疾病相关“症状”。在前期工作中，我们观察到DJ-1和Tau在哺乳动物细胞中表达时直接相互作用。因此，我们的工作将更好地确定DJ-1在线粒体功能和蛋白质错误折叠中的作用，这将有助于阐明其在帕金森病发病中的作用。这增加了对DJ-1生物学的洞察，最终可能有助于为这种和其他神经退行性疾病的治疗策略提供参考。

项目成果

Kynurenine 3-Monooxygenase Interacts with Huntingtin at the Outer Mitochondrial Membrane.

• DOI: 10.3390/biomedicines10092294
• 发表时间: 2022-09-15
• 期刊: Biomedicines
• 影响因子: 4.7

Bypassing mitochondrial defects rescues Huntington's phenotypes in Drosophila

• DOI: 10.1016/j.nbd.2023.106236
• 发表时间: 2023-07-28
• 期刊: NEUROBIOLOGY OF DISEASE
• 影响因子: 6.1
• 作者: Campesan，Susanna;del Popolo，Ivana;Giorgini，Flaviano
• 通讯作者: Giorgini，Flaviano

The Parkinson's Disease-Linked Protein DJ-1 Associates with Cytoplasmic mRNP Granules During Stress and Neurodegeneration.

• DOI: 10.1007/s12035-018-1084-y
• 发表时间: 2019-01
• 期刊: Molecular neurobiology
• 影响因子: 5.1
• 作者: Repici M;Hassanjani M;Maddison DC;Garção P;Cimini S;Patel B;Szegö ÉM;Straatman KR;Lilley KS;Borsello T;Outeiro TF;Panman L;Giorgini F
• 通讯作者: Giorgini F