Inflammatory regulation of cholesterol biosynthesis in a monogenic model of intracerebral haemorrhage

脑出血单基因模型中胆固醇生物合成的炎症调节

• 批准号: MR/T03291X/1
• 负责人: Paul Richard Kasher
• 金额: $ 66.59万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FT03291X%2F1
• 关键词: Inflammatory; regulation; cholesterol; biosynthesis; monogenic

Intracerebral haemorrhage (ICH) is a type of stroke caused by bursting of blood vessels within the brain which can lead to significant disability and/or death. Unfortunately, no medications are currently available for patients. A number of risk factors exist which can increase the likelihood of a person experiencing an ICH. One of these risk factors is low cholesterol levels, but how and why this may be associated with ICH is poorly understood. Cholesterol is a fatty substance that is necessary for several essential bodily functions, such as providing structural support for blood vessels. Too much cholesterol can lead to an accumulation of fatty deposits within vessels which can cause blockages and serious health conditions such as heart disease and ischaemic stroke. However, in ICH, it has been suggested that a reduction in cholesterol may lead to a weakening of the blood vessels in the brain, making them vulnerable to rupturing and bleeding. However, to date, this has not been investigated experimentally. The aim of this research proposal is to study the molecules that are responsible for producing cholesterol in brain blood vessels by using zebrafish models and human cells.Aicardi-Goutieres syndrome (AGS) is an inherited disease that occurs in children and young adults. AGS patients suffer from brain abnormalities and over-stimulation of an inflammatory molecule called type I interferon - which is normally only activated following a viral infection. Defects in 7 different genes (segments of DNA that encode specific proteins necessary for various body functions) can cause AGS. All of these patients experience the same brain and type I interferon features. However, one subgroup of AGS patients who carry defects in a gene called SAMHD1 also suffer from ICH. We do not know why ICH occurs specifically in these patients and not other AGS subgroups, but it suggests that SAMHD1 may have a previously unrecognised role in stabilising brain blood vessels. To help us try to understand this mechanism, animal models of the disease are required. Zebrafish are commonly used by scientists to model human conditions because they are 'see-through' and it is easy to watch how cells in the brain behave using powerful microscopes. We have made a zebrafish model which also have a defect in SAMHD1. Like the patients, these fish also have increased type I interferon levels and are susceptible to ICH. Genetic analysis has also revealed that these fish have a reduction in 14 genes that control the production of cholesterol. Remarkably, we have also shown that 8 of these genes are significantly reduced in ICH patient blood samples. These findings suggest that the development of ICH in this model is associated with increased type I interferon and a reduction in cholesterol production, and may also indicate a new biological function for SAMHD1 in AGS. Importantly, use of this model may provide essential clues into how and why low cholesterol may lead to ICH. This research proposal will allow us to continue to study these fish, alongside human brain blood vessel cells, so we can answer the following questions:1: Does a SAMHD1 defect cause a reduction in cholesterol genes specifically in blood vessels in the brain?2: Does a reduction in cholesterol genes and susceptibility to ICH occur in the SAMHD1 zebrafish model because of over-stimulation of type I interferon?3: Does interference of the other 6 AGS-related genes result in a reduction in cholesterol genes?To help answer these questions, we have designed a series of exciting experiments which will allow us to measure cholesterol genes and manipulate type I interferon levels, whilst visualising living brain blood vessels in fish and human cells. Answering these questions will provide new insight into SAMHD1-related AGS whilst also delivering important experimental evidence to support our understanding of how low cholesterol levels may lead to ICH.

脑出血 (ICH) 是一种由脑内血管破裂引起的中风，可导致严重残疾和/或死亡。不幸的是，目前还没有可供患者使用的药物。存在多种风险因素，这些因素会增加人发生脑出血的可能性。这些危险因素之一是低胆固醇水平，但人们对它与脑出血的关联方式和原因知之甚少。胆固醇是一种脂肪物质，是多种基本身体功能所必需的，例如为血管提供结构支持。过多的胆固醇会导致血管内脂肪沉积物堆积，从而导致血管堵塞和严重的健康问题，例如心脏病和缺血性中风。然而，在脑出血中，有人提出，胆固醇的减少可能会导致大脑中的血管变弱，使它们容易破裂和出血。然而，迄今为止，尚未对此进行过实验研究。该研究计划的目的是通过使用斑马鱼模型和人类细胞来研究负责在脑血管中产生胆固醇的分子。Aicardi-Goutieres 综合征 (AGS) 是一种发生在儿童和年轻人中的遗传性疾病。 AGS 患者患有大脑异常和一种称为 I 型干扰素的炎症分子的过度刺激，这种分子通常仅在病毒感染后才会被激活。 7 种不同基因（编码各种身体功能所需的特定蛋白质的 DNA 片段）的缺陷可能导致 AGS。所有这些患者都经历着相同的大脑和 I 型干扰素特征。然而，携带 SAMHD1 基因缺陷的 AGS 患者亚群也患有 ICH。我们不知道为什么 ICH 特别发生在这些患者中，而不是其他 AGS 亚组，但这表明 SAMHD1 在稳定脑血管方面可能具有以前未被认识到的作用。为了帮助我们尝试了解这种机制，需要该疾病的动物模型。斑马鱼通常被科学家用来模拟人类状况，因为它们具有“透视性”，并且可以使用强大的显微镜轻松观察大脑中细胞的行为。我们制作了一个斑马鱼模型，该模型在 SAMHD1 中也存在缺陷。与患者一样，这些鱼的 I 型干扰素水平也升高，并且容易患脑出血。基因分析还显示，这些鱼的 14 个控制胆固醇产生的基因有所减少。值得注意的是，我们还发现其中 8 个基因在 ICH 患者血液样本中显着减少。这些发现表明，该模型中 ICH 的发生与 I 型干扰素增加和胆固醇产生减少有关，也可能表明 SAMHD1 在 AGS 中具有新的生物学功能。重要的是，该模型的使用可以为低胆固醇如何以及为何导致脑出血提供重要线索。这项研究计划将使我们能够继续研究这些鱼以及人脑血管细胞，因此我们可以回答以下问题：1：SAMHD1 缺陷是否会导致大脑血管中胆固醇基因的减少？2：由于 I 型干扰素的过度刺激，SAMHD1 斑马鱼模型中胆固醇基因的减少和对 ICH 的易感性是否会发生？3：其他 6 种干扰素的干扰是否会导致 AGS 相关基因导致胆固醇基因减少？为了帮助回答这些问题，我们设计了一系列令人兴奋的实验，这些实验将使我们能够测量胆固醇基因并操纵 I 型干扰素水平，同时可视化鱼类和人类细胞中的活脑血管。回答这些问题将为 SAMHD1 相关 AGS 提供新的见解，同时提供重要的实验证据来支持我们对低胆固醇水平如何导致 ICH 的理解。

项目成果

Dirty Fish Versus Squeaky Clean Mice: Dissecting Interspecies Differences Between Animal Models of Interferonopathy.

• DOI: 10.3389/fimmu.2020.623650
• 发表时间: 2020
• 期刊: Frontiers in immunology
• 影响因子: 7.3
• 作者: Rutherford HA;Kasher PR;Hamilton N
• 通讯作者: Hamilton N

Characterization of a mutant samhd1 zebrafish model implicates dysregulation of cholesterol biosynthesis in Aicardi-Goutières syndrome.

• DOI: 10.3389/fimmu.2023.1100967
• 发表时间: 2023
• 期刊: FRONTIERS IN IMMUNOLOGY
• 影响因子: 7.3
• 作者: Withers, Sarah E.;Rowlands, Charlie F.;Tapia, Victor S.;Hedley, Frances;Mosneag, Ioana-Emilia;Crilly, Siobhan;Rice, Gillian I.;Badrock, Andrew P.;Hayes, Andrew;Allan, Stuart M.;Briggs, Tracy A.;Kasher, Paul R.
• 通讯作者: Kasher, Paul R.