Interrogation of links between risks and early pathogenesis at single cell resolution in a novel human ALS organoid neuraxis model

肌萎缩侧索硬化症（ALS）是一种运动神经元疾病，是一种致残和致命的神经系统疾病，具有快速进展的肌肉无力，目前无法治愈。在英国，大约每400人中就有1人有患上这种疾病的风险，这给患者、亲属和社会带来了越来越大的负担。由于手臂和腿部肌肉力量的丧失，生活质量下降，但偶尔也会出现记忆和行为问题。死亡最常见的原因是呼吸肌衰竭，确诊后的生存时间短至三年。尽管最近取得了一些进展，但仍有一些关键问题尚未解决，限制了有效治疗方法的发展。我们现在开始了解，ALS的损伤不仅发生在控制肌肉运动和思维的神经元中，还发生在许多其他受影响的支持细胞类型中，包括大脑和脊髓中的神经胶质细胞和免疫细胞。然而，我们还不知道：i）这种损伤何时以及如何在细胞中发生，ii）疾病如何在神经系统中从一个细胞传播到另一个细胞; iii）我们的遗传密码，DNA如何发生进一步的变化，以及这是否会影响我们一生的症状;以及环境风险因素，如脑损伤，影响ALS的发病和进展。找到这些问题的答案将指导治疗方法的发展，以预防或早期治疗这种疾病，在发生重大损伤或细胞损失之前。主要的问题是，很难研究最初的细胞干扰，因为我们通常无法在症状出现之前识别患者。我们也不能在这个早期阶段从他们身上获得大脑或脊髓样本。尽管培养皿中的动物和人类细胞培养物为这些问题提供了有用的见解，但它们并不适合单独了解全貌。这是因为培养皿中的动物细胞和人类细胞与大脑中的细胞相比，表现出了很大的不同。为了克服这个问题，我们首次从患者来源的干细胞中创建了一个新的模型系统，它可以在培养皿中以三维培养的形式生长，获得与人脑和脊髓相似的结构，细胞类型和连接。由于与器官的相似性，这些被称为类器官，通常被称为迷你大脑或迷你脊髓，其布线和某些细胞类型不同，因此它们无法获得意识。一个主要的优势是，我们的类器官模型允许研究ALS中发生的非常相似的干扰，我们现在可以研究这些干扰如何影响控制脊髓神经元的脑神经元的功能，这些神经元影响肌肉运动。另一个重要的优点是，我们可以从具有最常见的遗传异常的患者中生长这种模型，这些遗传异常导致ALS与患者具有广泛的相关性，并且也可以从这些细胞中生长这种模型，其中这种遗传问题得到纠正，这可以确保我们的观察特别反映ALS相关的问题。我们现在将使用这个可访问的实验性人类平台，并将其与其他创新工具相结合，帮助我们同时梳理单个细胞中的分子变化，提供了一个巨大的机会，了解疾病的复杂性开始，进展和可能的预防。我们的研究可能有助于识别可预防的细胞紊乱和那些分子变化，称为生物标志物，可能构成早期ALS的特定特征，这可能指导我们何时治疗，如何治疗以及将来治疗谁。MRC的支持将为我继续在人类类器官疾病模型方面的国际领导地位提供基础，促进我的学员的职业发展，并最终充分利用我们新颖的人类类器官模型，用于神经变性研究和治疗。

Amyotrophic lateral sclerosis (ALS) is a form of motor neuron disease, a disabling and fatal neurological condition with rapidly progressing muscle weakness, which is currently untreatable. In the UK, approximately 1 in 400 people are at risk of developing this disease, with an increasing burden on patients, relatives and society. Quality of life is reduced due to loss of muscle strength in the arms and legs, but occasionally also to memory and behavioural problems. Death is most commonly caused by failure of breathing muscles, with survival time as short as three years after diagnosis. Despite recent progress, there are key unresolved questions limiting the development of effective treatments.We are now beginning to understand that damage in ALS occurs not only in the neurons controlling our muscle movements and thinking, but also in many other affected supporting cell types, including glia and immune cells in the brain and the spinal cord. However, we do not know yet: i) when and how this damage occurs in the cells, ii) how the disease spreads in the nervous system from one cell to another; iii) how further changes can occur to our genetic code, the DNA and whether this could influence our symptoms throughout our lives; and iv) and how environmental risk factors, such as brain injuries, affect the onset and progression of ALS.Finding answers to these questions will guide the development of therapies to prevent or treat the disease early, before the major damage or cell loss occur. The main problem is that it is difficult to study the initial cell disturbances, as we often cannot identify the patients before the symptoms occur. Nor can we get brain or spinal cord samples from them at this early stage. Although animal and human cell cultures in the dish provided useful insight into these problems, they are not suitable alone to understand the full picture. The reason is that animal and human cells in the dish can behave quite differently when compared to their counterparts in the brain.To overcome this problem, for the first time, we have created a new model system from patient-derived stem cells, which can be grown as three-dimensional cultures in a dish, acquiring a similar structure, cell-types and connections as seen in the human brain and spinal cord. Because of the similarities to organs, these are called organoids, and often referred to mini-brains or mini-spinal cords with the difference in the wiring and certain cell types, so that they cannot gain consciousness. A major advantage is that our organoid model allows studies on very similar disturbances that occur in ALS, and we can now examine how these would effect the function of brain neurons that control spinal cord neurons that influence muscle movements. Another, important advantage is that we can grow this model from patients who have the most common genetic abnormality causing ALS with broad relevance to patients, and from those cells too in which this genetic problem is corrected, which can ensure that our observations specifically reflect ALS-related problems.In this proposal, we will now use this accessible experimental human platform and combine it with other innovative tools that help us to tease out molecular changes in individual cells at the same time, providing an immense opportunity to understand the complexity of disease initiation, progression and possible prevention. Our studies may help identify preventable cellular disturbances and those molecular changes, called biomarkers that may pose as specific signatures of early ALS, which may guide us when to treat, how to treat and who to treat in the future. The support by the MRC would provide the foundations for me to continue my international-level leadership in human organoid disease models, to facilitate the career development of my trainees, and ultimately to fully harness our novel human organoid models for discoveries in neurodegeneration research and therapeutics.