Defining mechanisms of blood-brain barrier dysfunction in cerebral small vessel disease using advanced 3D in vitro models.

神经退行性疾病（NDD）是导致脑细胞进行性死亡的不可治愈和衰弱的疾病。这会导致运动障碍、认知能力下降和残疾增加。目前的NDD疗法治疗症状，而不是潜在的病理变化。因此，NDD是医疗保健提供者和研究科学家的主要挑战。NDD主要发生在老年人中，其中脑小血管疾病（cSVD）很常见，并导致全球至少45%（约2100万人）的痴呆症。痴呆症的总社会成本为每年260亿英镑，其中包括NHS和社会护理的86亿英镑。基于对分子病理学的理解，开发新的治疗方法是一个明确而未满足的临床需求。人类大脑需要一个稳定的微环境来确保正常运作。一种专门的多细胞血管结构，血脑屏障（BBB），调节血液和大脑之间的分子流动。NDD发展的一个关键方面是BBB的泄漏和炎症介质（作用于血管和/或细胞以促进炎症反应的信使）在大脑周围的扩散。我们不了解这些介质如何穿过紧密的屏障并导致BBB破坏，或者不同BBB细胞在这些过程中的确切作用。NDD的病理生理学多种多样，迫切需要有效的治疗。许多以前在动物身上被证明有效的药物在人类身上都没有产生同样的效果，仅仅是因为我们是不同的。此外，动物研究不允许在没有继发性年龄相关并发症的模型中研究疾病机制，而基于2D细胞的模型通常过于简化，无法充分概括BBB生物学。出于这个原因，我设计了一个更简单，更快，更生理相关的人类疾病细胞模型。在这个项目中，我将开发我的新颖的，动态的，微生理学的“BBB芯片”，模仿人类大脑的相关生理和功能。我将确定血压、血流速度和心跳等因素如何控制血脑屏障功能。我将使用直接从人脑中收获的细胞（原代细胞）和具有cSVD相关基因突变的干细胞，使用最先进的基因编辑工具CRISPR-Cas9来生成生理相关的人类疾病模型。我将研究当由完整或泄漏的血脑屏障支持时，脑细胞的生物学变化。这种在生理模型中对BBB功能的新分析将导致识别与cSVD进展相关的新细胞过程，并帮助我们了解如何利用BBB来保护大脑免受疾病的影响。这是使用任何其他方法都不可能实现的。因此，我准备对健康和疾病中的大脑功能进行重要的新理解，并发现可以阻止相关痴呆症发生和发展的新药和靶点。

Neurodegenerative disorders (NDDs) are incurable and debilitating conditions that result in the progressive death of brain cells. This leads to movement disorder, cognitive decline and increased disability. Current therapies for NDDs treat symptoms, not the underlying pathological changes. The NDDs are therefore major challenges to healthcare providers and research scientists. NDDs occurs mostly in older people in whom cerebral small vessel disease (cSVD) is common and contributes to at least 45% (~21 million people) of dementia worldwide. The aggregate societal cost of dementia is £26 billion per year, including £8.6 billion for NHS and social care. There is a clear and unmet clinical need to develop new therapies based on understanding the molecular pathologies.The human brain needs a stable microenvironment to ensure proper functioning. A specialized multi-cellular blood vessel structure, the blood-brain barrier (BBB), regulates the flow of molecules between the blood and the brain. A key aspect of NDD development is the leakiness of the BBB and the spread of inflammatory mediators (messengers that acts on blood vessels and/or cells to promote an inflammatory response) around the brain. We do not understand how these mediators cross the tight barrier and cause BBB breakdown, or the precise role of different BBB cells in these processes.NDDs are diverse in their pathophysiology and effective treatments are urgently needed. Many drugs that have been previously shown to be effective in animals have failed to produce the same effects in humans, simply because we are different. Moreover, animal studies do not allow studying disease mechanisms in a model that is free from secondary, age-related complications, while 2D cell-based models are often too simplified to sufficiently recapitulate BBB biology. For this reason, I have designed a simpler, faster, and more physiologically-relevant human cellular model of disease. In this project, I will develop my novel, dynamic, microphysiological 'BBB-on-a-chip' that mimics the relevant physiology and functionality of the human brain. I will determine how factors such as blood pressure, blood flow rate and heartbeat control BBB function. I will use cells harvested directly from human brains (primary cells) and stem cells with cSVD-relevant genetic mutations using a state-of-the-art genetic editing tool called CRISPR-Cas9 to generate a physiologically-relevant human disease model. I will investigate how the biology of brain cells changes when supported by an intact or a leaky BBB. This new analysis of BBB function in a physiological model will lead to the identification of new cellular processes relevant to cSVD progression, and help us understand how to harness the BBB to shield the brain from disease.This is not possible using any other approach. I am therefore poised to develop significant new understanding of brain function in health and disease and discover new drugs and targets that can stop the occurrence and development of related dementias.