Screening for, and characterisation of, novel immune cell extravasation genes in Drosophila, mice and man

果蝇、小鼠和人中新型免疫细胞外渗基因的筛选和表征

• 批准号: MR/V011294/1
• 负责人: Paul Martin
• 金额: $ 214.93万
• 依托单位: University of Bristol
• 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%2FV011294%2F1
• 关键词: Screening; characterisation; novel; immune; cell

An inflammatory response is pivotal in many normal physiological responses, for example wherever there is a wound or site of infection. In such scenarios, if inflammation is delayed or insufficient then the consequences to health can be catastrophic. Conversely, if the inflammatory response is excessive or slow to resolve, then 'chronic' inflammation can also lead to several pathologies, ranging from tissue scarring through to atherosclerosis or even cancer. A better understanding of how inflammatory cells are recruited to their target tissues will help guide us how the inflammatory response might be modulated therapeutically to treat these conditions.One of the key 'rate-limiting' steps in an inflammatory response is the movement of leukocytes (white blood cells) from the circulation across blood vessel walls (known as 'extravasation') to sites of damage or infection. However, despite decades of research in this field, many aspects of this step in leukocyte recruitment remain poorly understood and there is still much to learn; this is in part because breaching of vessel walls is a highly complex process to dissect at the molecular level and it is incredibly difficult to image in opaque tissues of traditional mammalian models (e.g. mouse).In Bristol we have recently developed a new model in which to study immune cell 'extravasation' using the fruitfly, Drosophila. Fruitflies offer many advantages for this research, being genetically 'tractable' (easy to mutate and study individual genes) and also translucent (enabling us to watch these movements live using microscopy). Since fruitflies largely have an 'open circulation' without discrete blood vessels, they were not previously considered a useful model for this field. However, we have identified a period in pupal life when immune cells circulate through the wing "veins" and a laser-induced wound triggers immune cells to leave the veins and move towards the damage. We have already used this model to identify one novel receptor protein (Tre1) that is essential for immune cell extravasation, and excitingly, the equivalent gene in mammals (GPR84) has proven to be required for neutrophil extravasation in mice (our pilot studies in QMUL), and is associated with several inflammatory conditions in human patients.Our findings suggest that Drosophila may provide a powerful fast-track approach to identify more genes required in immune cells (or vessel cells) for this pivotal step in inflammation. Here we propose to use our fly model to initiate such a 'screen' and develop an even faster screening process in newly hatched adults to ultimately search through the whole genome. Studies in the fly will also provide new detail on how proteins like Tre1 function at the molecular level. At QMUL, we will complement this work by exploring how the equivalent genes function in mammals during extravasation and investigate how these genes might impact on important physiological and pathological processes, such as healing of a skin wound and during peritonitis.Ultimately, we want to identify which of the genes highlighted by our studies in fly and mouse are most promising as targets for modulation of inflammation in the clinic. To extend our findings towards translation, we will undertake studies using human cells where we knockdown candidate genes/signalling pathways in human vessel or immune cells to determine how this impacts leukocyte extravasation. Alongside this, we will use "population health" approaches to search human genetics data to identify which of our candidate genes are associated with human disease.In summary, we propose to employ a multi-disciplinary, cross-institutional and multi-organism approach to uncover more genes with important functions in immune cell extravasation, that will provide potential therapeutic targets for inflammatory disorders in the clinic. We envision this multi-modal approach will be far more insightful than studies in a single model alone.

在许多正常的生理反应中，炎症反应至关重要，例如在任何伤口或感染部位。在这种情况下，如果炎症被延迟或不足，那么对健康的后果可能会造成灾难性。相反，如果炎症反应过度或缓慢解决，则“慢性”炎症也会导致几种病理，从组织疤痕到动脉粥样硬化甚至癌症不等。更好地了解如何将炎症细胞募集到目标组织将有助于我们如何在炎症反应中调节炎症反应如何进行治疗以治疗这些状况。在炎症反应中，关键的“限制限制”步骤之一是白细胞（白细胞）在血管上循环壁的流动（白细胞）在血管上循环造成的（已知为“膨胀”或损坏的损害或损坏。然而，尽管在这一领域进行了数十年的研究，但在白细胞招募中，这一步骤的许多方面仍然很少了解，还有很多东西要学习。这部分是因为突破容器壁是一个高度复杂的过程，可以在分子水平上进行剖析，并且在传统哺乳动物模型的不透明组织（例如小鼠）中，很难形象。果蝇为这项研究提供了许多优势，从遗传上“可诱捕”（易于突变和研究单个基因），也具有半透明（使我们能够使用显微镜观察这些运动）。由于果蝇在很大程度上具有没有离散血管的“开放循环”，因此它们以前不被认为是该领域的有用模型。然而，我们已经确定了pupal寿命中的一个时期，当时免疫细胞通过机翼“静脉”循环，激光诱导的伤口会触发免疫细胞，从而留下静脉并朝向损伤。我们已经使用该模型来识别一种对免疫细胞渗出至关重要的新型受体蛋白（TRE1），令人兴奋的是，事实证明，哺乳动物中的等效基因（GPR84）是必需的，这是嗜中性粒细胞渗出所必需的，即在小鼠中嗜中性粒细胞渗出，在QMUL中的试验性研究有更多的疾病，可以在QMUL中识别一些炎症。在免疫细胞（或血管细胞）中，该关键步骤在炎症中。在这里，我们建议使用我们的飞行模型来启动这种“屏幕”，并在新孵化的成年人中开发更快的筛选过程，以最终搜索整个基因组。即时研究还将提供有关分子水平上蛋白质诸如TRE1诸如蛋白质如何功能的新细节。在Qmul，我们将通过探索伸出过程中等效基因在哺乳动物中的作用，并研究这些基因如何影响这些基因对重要的生理和病理学过程的影响，例如皮肤伤口的愈合和腹膜炎期间的愈合。我们希望确定哪些基因在我们的基因中识别出我们最有可能的纽约市的研究基因，以实现目标，以实现型号的契约。为了扩展我们的发现向翻译，我们将使用人类细胞进行研究，在该研究中，我们在人体血管或免疫细胞中敲除候选基因/信号通路，以确定这如何影响白细胞渗出。除此之外，我们将使用“人口健康”方法来搜索人类遗传学数据，以确定我们的哪些候选基因与人类疾病有关。总结，我们建议采用一种多学科的，跨机构和多生物的方法来揭示更多在免疫细胞伸出的重要功能的重要功能，从而可以为炎症性疾病提供潜在的治疗目标。我们设想这种多模式方法将比单一模型中的研究更具洞察力。