Dissecting the molecular mechanisms of lysosome:ER contact site formation and their relevance to neurodegenerative disease

剖析溶酶体的分子机制：内质网接触位点的形成及其与神经退行性疾病的相关性

• 批准号: MR/V013882/1
• 负责人: Emily Eden
• 金额: $ 70.82万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FV013882%2F1
• 关键词: Dissecting; molecular; mechanisms; lysosome; ER

Human cells contain membrane enclosed compartments, called organelles, that perform specialised tasks. Membrane contact sites, that bridge the membranes of neighbouring organelles, provide platforms for communication between organelles. Cholesterol is an important component of membranes. Cells have two sources of cholesterol: it can either be derived from our diet or newly synthesised by the cell. Dietary cholesterol is taken up into the cell into a compartment called the endosome, from where it is trafficked to the lysosome for onward transport to another compartment, the endoplasmic reticulum (ER). The ER is the site of cholesterol synthesis within the cell and the arrival of dietary cholesterol from the lysosome switches off the synthesis of new cholesterol. When dietary cholesterol fails to be transported from the lysosome to the ER, it accumulates in the lysosome, while cholesterol synthesis in the ER still continues. The resulting imbalance in cellular cholesterol is toxic to the cell and is associated with neurodegenerative disease. We have recently shown an important role for membrane contact sites between the ER and lysosomes in regulating the cholesterol balance by transporting cellular cholesterol to the right location. The aim of this research proposal is to determine exactly how these contact sites are formed, if they transport other lipids as well as cholesterol and if they can be targeted for therapeutic benefit in neurodegenerative disease.Niemann Pick disease type-C (NPC) is a rare but devastating progressive neurodegenerative disease that often starts in early childhood. We know that most (95%) cases of NPC are caused by mutations in a gene that encodes the NPC protein NPC1. NPC1 is on the lysosome membrane and is required for dietary cholesterol to exit the lysosome for transport to the ER. Previous work by our group has found that NPC1 forms part of the lysosome-ER bridge that cholesterol can travel across. In cells from NPC patients, the lysosome fails to connect properly with the ER. As a result, cholesterol accumulates in the lysosome and the lysosome stops working properly. In this proposed work we intend to find out how NPC1 bridges the two organelles and if its interactions with partners on the ER are affected by levels of dietary cholesterol in the lysosome.As well as cholesterol, other lipids also accumulate in lysosomes in NPC that are believed to contribute to the disease progression. Indeed, the only current licensed therapeutic for NPC (miglustat) inhibits the synthesis of these lipids. Although miglustat is not a cure, the fact that it slows progression of the disease shows that imbalance of these lipids is toxic to the cell. Our preliminary data suggests that some of these lipids might also be transported across contact sites, to the ER where they are degraded. In this project we will improve our understanding of the relationship between membrane contact sites and lipid metabolism. We recently showed that artificially bridging lysosomes to the ER can reverse cholesterol accumulation in cells lacking NPC1. This is exciting as it could have therapeutic implications for NPC. We will assess different ways to expand membrane contact sites in cellular models of NPC and build on these studies to see the effect of increased contact sites in animal models. Zebrafish are an excellent model system for studying NPC. NPC zebrafish models mimic many mammalian NPC phenotypes, including lipid accumulation, and movement defects. We will therefore generate zebrafish models of NPC in which to study ER-lysosome contact sites and test our hypothesis that expanding these contact sites will rescue both lipid accumulation and downstream neurodegeneration /movement defects. This may yield novel therapeutic strategies for the treatment of NPC and other neurodegenerative diseases with lipid storage defects.

人类细胞包含执行专业任务的膜封闭室，称为细胞器。弥合相邻细胞器的膜的膜接触地点为细胞器之间的通信提供了平台。胆固醇是膜的重要组成部分。细胞有两个胆固醇来源：它可以从我们的饮食中得出，也可以由细胞新合成。饮食中的胆固醇被带入细胞中，进入一个称为内体的隔室，从那里被贩运到溶酶体，以继续运输到另一个隔室，即内质网（ER）。 ER是细胞内胆固醇合成的部位，并且是从溶酶体中脱脂胆固醇的到来的，从而关闭了新胆固醇的合成。当饮食中的胆固醇未能从溶酶体转移到ER时，它会积聚在溶酶体中，而ER中的胆固醇合成仍在继续。细胞胆固醇导致的失衡对细胞有毒，并且与神经退行性疾病有关。最近，我们通过将细胞胆固醇传输到正确的位置来调节胆固醇平衡中ER和溶酶体之间的膜接触位点的重要作用。这项研究建议的目的是确切确定这些接触部位的形成方式，如果它们运输其他脂质以及胆固醇，以及是否可以针对神经退行性疾病的治疗益处作为靶向。Niemann Pick type-type-C（NPC）是一种罕见但造成毁灭性的渐进性神经变性疾病，通常在早期儿童中开始。我们知道，大多数NPC病例（95％）是由编码NPC蛋白NPC1的基因中的突变引起的。 NPC1位于溶酶体膜上，饮食中胆固醇需要退出溶酶体以运输到ER。我们小组的先前工作发现NPC1构成了胆固醇可以穿越的溶酶体-ER桥的一部分。在NPC患者的细胞中，溶酶体无法与ER正确连接。结果，胆固醇积聚在溶酶体中，溶酶体停止正常工作。在这项拟议的工作中，我们打算找出NPC1如何桥接这两个细胞器以及它与ER的伴侣的相互作用是否受溶酶体中饮食中胆固醇水平的影响。胆固醇，其他脂质在NPC中也积累了有助于疾病进展的NPC中的溶酶体。实际上，NPC（Miglustat）的唯一当前有执照的治疗性抑制了这些脂质的合成。尽管Miglustat不是治愈方法，但它减慢疾病进展的事实表明，这些脂质的不平衡对细胞有毒。我们的初步数据表明，其中一些脂质也可能会跨接触地点运输到ER降解的ER。在这个项目中，我们将提高对膜接触站点与脂质代谢之间关系的理解。我们最近表明，将溶酶体人为地桥接到ER可以逆转缺乏NPC1的细胞中的胆固醇积累。这很令人兴奋，因为它可能对NPC具有治疗意义。我们将评估在NPC的细胞模型中扩展膜接触位点的不同方法，并在这些研究的基础上构建，以查看动物模型中接触位点增加的效果。斑马鱼是研究NPC的出色模型系统。 NPC斑马鱼模型模仿许多哺乳动物的NPC表型，包括脂质积累和运动缺陷。因此，我们将生成NPC的斑马鱼模型，在其中研究ER溶质体接触位点，并测试我们的假设，即扩大这些接触位点将挽救脂质积累和下游神经变性 /运动缺陷。这可能会产生新颖的治疗策略，用于治疗NPC和其他神经退行性疾病，并具有脂质储存缺陷。

项目成果

Thank ORP9 for FFAT: With endosomal ORP10, it's fission accomplished!

• DOI: 10.1083/jcb.202112057
• 发表时间: 2022-01-03
• 期刊: The Journal of cell biology
• 作者: Wong LH;Martello A;Eden ER
• 通讯作者: Eden ER

Sphingosine kinases regulate ER contacts with late endocytic organelles and cholesterol trafficking.

• DOI: 10.1073/pnas.2204396119
• 发表时间: 2022-09-27
• 期刊: Proceedings of the National Academy of Sciences of the United States of America
• 影响因子: 11.1

Membrane trafficking: Retrofusion as an escape route out of the endosome

• DOI: 10.1016/j.cub.2021.07.055
• 发表时间: 2021-09-13
• 期刊: CURRENT BIOLOGY
• 影响因子: 9.2
• 作者: Eden, Emily R.;Futter, Clare E.
• 通讯作者: Futter, Clare E.

Editorial: Cell compartments and intracellular trafficking of lipids and proteins: Impact on biomedicine.

• DOI: 10.3389/fcell.2022.1087214
• 发表时间: 2022
• 期刊: Frontiers in cell and developmental biology
• 影响因子: 5.5

Current methods to analyze lysosome morphology, positioning, motility and function.

• DOI: 10.1111/tra.12839
• 发表时间: 2022-05
• 期刊: TRAFFIC
• 影响因子: 4.5
• 作者: Barral, Duarte C.;Staiano, Leopoldo;Guimas Almeida, Claudia;Cutler, Dan F.;Eden, Emily R.;Futter, Clare E.;Galione, Antony;Marques, Andre R. A.;Medina, Diego Luis;Napolitano, Gennaro;Settembre, Carmine;Vieira, Otilia V.;Aerts, Johannes M. F. G.;Atakpa-Adaji, Peace;Bruno, Gemma;Capuozzo, Antonella;De Leonibus, Elvira;Di Malta, Chiara;Escrevente, Cristina;Esposito, Alessandra;Grumati, Paolo;Hall, Michael J.;Teodoro, Rita O.;Lopes, Susana S.;Luzio, J. Paul;Monfregola, Jlenia;Montefusco, Sandro;Platt, Frances M.;Polishchuck, Roman;De Risi, Maria;Sambri, Irene;Soldati, Chiara;Seabra, Miguel C.
• 通讯作者: Seabra, Miguel C.