Dysregulation of RNA processing as a driver of motor neuron dysfunction in Amyotrophic Lateral Sclerosis

RNA 加工失调是肌萎缩侧索硬化症运动神经元功能障碍的驱动因素

• 批准号: MR/Y014286/1
• 负责人: Akshay Bhinge
• 金额: $ 100.86万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FY014286%2F1
• 关键词: Dysregulation; RNA; processing; driver; motor

Amyotrophic Lateral Sclerosis (ALS) (also known as motor neuron disease), is caused by a loss of motor nerves or neurons. These motor nerves carry signals from the brain and spinal cord to the peripheral muscles allowing everyday movements. Loss of motor nerves in these patients leads to progressive muscle paralysis and eventual death due to failure of muscles that allow us to breath. About ~10-15% of ALS cases have a family history and specific defects, called mutations, in several genes with diverse functions are known to cause ALS. However, the processes driving motor neuron loss are poorly understood. Though the cause of ALS is unknown, many of the nerves affected in these patients show a common feature. This feature involves incorrect migration of a protein called TDP43 from within the nucleus of a cell, outside into its cytoplasm. The nucleus is the command centre of the cell and contains our DNA with specific instructions on how to make different proteins, the workhorses in a cell. The cytoplasm is the gel-like liquid within the cell that contains the nucleus and has the machinery to make proteins. Each of the nucleus and the cytoplasm have defined roles that are dependent on precise availability of specific proteins. Thus, any change in the proteins' locations will interfere with the normal activity of nerve cells resulting in their death. Relocation, also called mislocalization, of TDP43 protein from the nucleus to the cytoplasm perturbs the normal function of the nerve cells causing them to die. We have developed a new way to trigger TDP43 protein mislocalization in human nerve cells in a dish. This will allow us to look at the consequences of this relocation in detail. With the advent of a new stem cell technology called reprogramming, skin or blood cells from patients can be converted into an embryonic state. These reprogrammed cells are called induced pluripotent stem cells (iPSC) and have the potential to be converted to any type of cell in the body. Consequently, iPSC's from ALS patients can now be coaxed to become motor nerves i.e., the same kind of cells that are lost in ALS patients. This technology enables the development of human models of ALS in a dish, allowing scientists to interrogate what goes wrong within these cells to cause them to die in ALS. Using such models, we have uncovered that an important molecular process required for nerve cell survival called RNA splicing is defective in ALS. Using the process of RNA splicing, nerve cells create many different types of proteins that are required for normal function. Incorrect execution of this process leads to the generation of ineffective proteins, which can lead to problems in the structure and function of nerve cells. In this proposal, we will use the iPSC technology to generate motor nerves and use these nerves to understand how TDP43 mislocalization causes RNA splicing defects and the role of RNA splicing in ALS. The results of this study will generate deeper insights into why ALS motor nerves die and highlight new ways to develop therapeutic drugs in our fight against ALS.

肌萎缩侧索硬化症 (ALS)（也称为运动神经元疾病）是由运动神经或神经元丧失引起的。这些运动神经将信号从大脑和脊髓传递到周围肌肉，以进行日常运动。这些患者运动神经的丧失会导致进行性肌肉瘫痪，并最终因呼吸肌肉衰竭而死亡。大约 10-15% 的 ALS 病例有家族史，并且具有不同功能的多个基因的特定缺陷（称为突变）已知会导致 ALS。然而，人们对运动神经元损失的驱动过程知之甚少。尽管 ALS 的病因尚不清楚，但这些患者受影响的许多神经表现出一个共同特征。这一特征涉及一种名为 TDP43 的蛋白质从细胞核内错误迁移到细胞质中。细胞核是细胞的指挥中心，包含我们的 DNA，以及如何制造不同蛋白质（细胞中的主力）的具体指令。细胞质是细胞内的凝胶状液体，含有细胞核并具有制造蛋白质的机制。每个细胞核和细胞质都有明确的作用，这些作用取决于特定蛋白质的精确可用性。因此，蛋白质位置的任何变化都会干扰神经细胞的正常活动，导致神经细胞死亡。 TDP43 蛋白从细胞核到细胞质的重新定位（也称为错误定位）会扰乱神经细胞的正常功能，导致神经细胞死亡。我们开发了一种新方法来触发培养皿中人类神经细胞中 TDP43 蛋白的错误定位。这将使我们能够详细了解这次搬迁的后果。随着一种称为重编程的新干细胞技术的出现，患者的皮肤或血细胞可以转化为胚胎状态。这些重新编程的细胞被称为诱导多能干细胞（iPSC），有可能转化为体内任何类型的细胞。因此，来自 ALS 患者的 iPSC 现在可以被诱导成为运动神经，即与 ALS 患者丢失的细胞类型相同。这项技术能够在培养皿中开发 ALS 人类模型，使科学家能够探究这些细胞内的问题导致它们死于 ALS。使用此类模型，我们发现神经细胞生存所需的重要分子过程（称为 RNA 剪接）在 ALS 中存在缺陷。利用 RNA 剪接过程，神经细胞产生正常功能所需的许多不同类型的蛋白质。该过程的不正确执行会导致无效蛋白质的产生，从而导致神经细胞的结构和功能出现问题。在本提案中，我们将利用 iPSC 技术生成运动神经，并利用这些神经来了解 TDP43 错误定位如何导致 RNA 剪接缺陷以及 RNA 剪接在 ALS 中的作用。这项研究的结果将更深入地了解 ALS 运动神经死亡的原因，并强调开发抗 ALS 治疗药物的新方法。