EXPLORING THE ROLE AND THERAPEUTIC POTENTIAL OF RAB GTPASES IN HUNTINGTON'S DISEASE

探索 RAB GTP 酶在亨廷顿病中的作用和治疗潜力

• 批准号: MR/R011621/1
• 负责人: Flaviano Giorgini
• 金额: $ 100.21万
• 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: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FR011621%2F1
• 关键词: EXPLORING; ROLE; THERAPEUTIC; POTENTIAL; RAB

Huntington's disease (HD) is a fatal neurodegenerative disorder characterised by the loss of vulnerable neurons in the brain. The disease is caused by an increase in the size of a repeated DNA sequence which encodes for the amino acid glutamine in the huntingtin (HTT) protein. If the number of glutamines in the HTT protein increases beyond a critical length, it misfolds and clumps together to form protein aggregates, disrupting many vital cellular processes. Notably, other genes can significantly modify the onset of symptoms. This suggests there are many potential therapeutic targets in the human genome capable of significantly altering disease.Studies in patients and disease models have revealed that mutant HTT (mHTT) affects many cellular pathways, including intracellular vesicle trafficking. This is a vital process for the movement of proteins and nutrients between different parts of the cell. Previous work by our laboratory and others has shown that vesicle trafficking defects in HD are at least partly due to a family of proteins called Rab GTPases. These proteins are vital for nearly every aspect of vesicle trafficking, and the function of several Rabs is impaired in HD and other related disorders, including Parkinson's disease. Interestingly, the non-mutant HTT protein may be important for the normal function of some Rabs, which may contribute to their dysfunction in HD.We and others have noted that increased expression of three Rab GTPases - Rab5, Rab8 and Rab11 - reduces disease-relevant symptoms in cultured mammalian cell and fruit fly models of HD. While the role of these Rabs in HD has been explored, little is known about the importance of the ~60 other mammalian Rabs. To address this question we performed a systematic screen of 130 mammalian Rabs and associated genes and identified 8 that modulated mHTT toxicity in mammalian cells. Several additional Rabs have also been identified in independent screens for genes that alter mHTT toxicity and/or misfolding. In this research proposal we aim to further investigate the role of Rab GTPases in HD and explore their therapeutic potential. Notably, this will include the first characterisation of the role of Rabs in peripheral immune cell dysfunction in HD by analysing patient-derived samples. Immune cells are hyper-reactive in HD, producing inflammatory molecules that may contribute to progression of the disease, and Rabs contribute to the secretion of these molecules.Understanding Rab dysfunction in HD is critical for determining their disease and therapeutic relevance, the mode of action of disease modifying Rabs and for formulating therapeutic approaches. We will address this by investigating whether the amount, function or cellular location of candidate Rabs is altered in HD models and patient samples, and how this impacts upon Rab-dependant processes. To validate the protective properties of candidate Rabs, and prioritise them for further study, they will be tested in fruit fly and mouse HD models, allowing us to study the impact of mHTT and Rabs on the complex interactions that occur between cells in living multicellular organisms. Promising candidates will be tested in physiologically relevant human HD model cells, including neurons and immune cells from patients. Drug-like compounds which alter Rab function will also be tested, and alternative methods for targeting them explored. To further inform potential therapeutic approaches and prioritise candidates the mechanisms by which they modify HD relevant-phenotypes will be studied. Our preliminary findings suggest that many candidates increase the clearance of mHTT from the cell, and we will confirm these findings using additional HD models and approaches. In total, this work will help define the role of Rab GTPases in HD, assess their therapeutic potential and inform therapeutic strategies. As Rab dysfunction has been implicated in several diseases these findings may also have broader significance.

亨廷顿氏病（HD）是一种致命的神经退行性疾病，其特征在于大脑中脆弱神经元的丧失。这种疾病是由编码亨廷顿蛋白（HTT）中氨基酸谷氨酰胺的重复DNA序列的大小增加引起的。如果HTT蛋白中谷氨酰胺的数量增加超过临界长度，它就会错误折叠并聚集在一起形成蛋白质聚集体，破坏许多重要的细胞过程。值得注意的是，其他基因可以显着改变症状的发作。这表明人类基因组中存在许多能够显著改变疾病的潜在治疗靶点。对患者和疾病模型的研究表明，突变HTT（mHTT）影响许多细胞途径，包括胞内囊泡运输。这是蛋白质和营养物质在细胞不同部分之间移动的重要过程。我们实验室和其他人以前的工作表明，HD中的囊泡运输缺陷至少部分是由于一种称为Rab GTP酶的蛋白质家族。这些蛋白质对于囊泡运输的几乎每个方面都是至关重要的，并且在HD和其他相关疾病（包括帕金森病）中，几种Rabs的功能受损。有趣的是，非突变HTT蛋白可能是重要的一些Rabs的正常功能，这可能有助于他们的功能障碍，在HD。我们和其他人已经注意到，三个Rab GTP酶的表达增加-Rab 5，Rab 8和Rab 11-减少疾病相关的症状，在培养的哺乳动物细胞和果蝇模型的HD。虽然这些Rabs在HD中的作用已被探索，但对其他约60种哺乳动物Rabs的重要性知之甚少。为了解决这个问题，我们进行了130哺乳动物Rabs和相关基因的系统性筛选，并确定了8个调节mHTT在哺乳动物细胞中的毒性。还在改变mHTT毒性和/或错误折叠的基因的独立筛选中鉴定了几种额外的Rab。在这项研究中，我们的目标是进一步研究Rab GTP酶在HD中的作用，并探索其治疗潜力。值得注意的是，这将包括通过分析患者来源的样本首次表征Rabs在HD外周免疫细胞功能障碍中的作用。HD患者的免疫细胞反应过度，产生炎症分子，可能导致疾病的进展，Rabs参与这些分子的分泌。了解HD患者的Rab功能障碍对于确定其疾病和治疗相关性、疾病修饰Rabs的作用模式以及制定治疗方法至关重要。我们将通过研究候选Rabs的数量、功能或细胞位置在HD模型和患者样本中是否发生改变，以及这如何影响Rabs依赖性过程来解决这一问题。为了验证候选Rabs的保护特性，并将其优先用于进一步研究，它们将在果蝇和小鼠HD模型中进行测试，使我们能够研究mHTT和Rabs对活的多细胞生物体中细胞之间发生的复杂相互作用的影响。有希望的候选人将在生理相关的人类HD模型细胞中进行测试，包括来自患者的神经元和免疫细胞。还将测试改变Rab功能的药物样化合物，并探索靶向它们的替代方法。为了进一步告知潜在的治疗方法并优先考虑候选药物，将研究它们修饰HD相关表型的机制。我们的初步研究结果表明，许多候选人增加了mHTT从细胞中的清除，我们将使用其他HD模型和方法来证实这些发现。总之，这项工作将有助于确定Rab GTP酶在HD中的作用，评估其治疗潜力并为治疗策略提供信息。由于Rab功能障碍与几种疾病有关，这些发现也可能具有更广泛的意义。

项目成果

Additional file 2 of Human Huntington's disease pluripotent stem cell-derived microglia develop normally but are abnormally hyper-reactive and release elevated levels of reactive oxygen species

人类亨廷顿病多能干细胞衍生的小胶质细胞发育正常但异常过度反应并释放水平升高的活性氧的附加文件 2

• DOI: 10.6084/m9.figshare.14451028
• 发表时间: 2021
• 作者: O'Regan G

Additional file 1 of Human Huntington's disease pluripotent stem cell-derived microglia develop normally but are abnormally hyper-reactive and release elevated levels of reactive oxygen species

人类亨廷顿病多能干细胞衍生的小胶质细胞发育正常但异常过度反应并释放水平升高的活性氧的附加文件 1

• DOI: 10.6084/m9.figshare.14451025
• 发表时间: 2021
• 作者: O'Regan G

Wild-type huntingtin regulates human macrophage function.

野生型亨廷顿调节人类巨噬细胞功能。

• DOI: 10.1038/s41598-020-74042-8
• 发表时间: 2020-10-14
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: O'Regan GC;Farag SH;Ostroff GR;Tabrizi SJ;Andre R
• 通讯作者: Andre R

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

Therapeutic Targeting of Rab GTPases: Relevance for Alzheimer's Disease.

• DOI: 10.3390/biomedicines10051141
• 发表时间: 2022-05-16
• 期刊: Biomedicines
• 影响因子: 4.7