Characterising the Physiological Role, Function and Structure of the Inhibitory LILRB3 Receptor on Neutrophils using a Novel Bacterial Ligand

使用新型细菌配体表征中性粒细胞抑制性 LILRB3 受体的生理作用、功能和结构

• 批准号: BB/V006495/1
• 负责人: Alex McCarthy
• 金额: $ 70.54万
• 依托单位: Imperial College London
• 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=BB%2FV006495%2F1
• 关键词: Characterising; Physiological; Role; Function; Structure

Hyper-active neutrophil responses are associated with infectious disease, inflammatory disease and trauma in humans and animals. Neutrophils are critical for protecting hosts from invading pathogens and coordinating inflammation. However, if activated at the wrong time, wrong place or to the wrong extent they can damage the host and/or induce severe inflammation. Effective strategies to reprogram hyperactive responses are clearly needed for diseases characterised by neutrophil-driven inflammation. Inhibitory receptors are key molecules expressed by human and animal neutrophils that suppress their activation and ensure that they are not activated prematurely or excessively. Their importance in maintaining health is demonstrated by the increased susceptibility of mice that lack inhibitory receptors to inflammatory and infectious diseases. Targeting inhibitory receptors is a promising strategy to suppress hyper-active neutrophil responses. However, the individual inhibitory receptors that coordinate neutrophil regulation are not fully understood. This is significant as we are likely unaware of the considerable potential that inhibitory receptors offer for the development of novel immunosuppressive therapies.LILRB3 is an inhibitory receptor expressed on human neutrophils that is a potent inhibitor of activation, degranulation, phagocytosis and microbial killing. Importantly, LILRB3 is highly expressed on circulating neutrophils. This contrasts the low expression levels of most inhibitory receptors, that are upregulated upon neutrophil activation. Therefore, LILRB3 is in a unique group of inhibitory receptors that could be targeted to switch off neutrophil mobilisation, activation and hyper-responses in disease situations. Remarkably, the in vivo functions, signalling mechanisms and structure of LILRB3 are unknown. Thus, there is a fundamental gap in our knowledge of how neutrophils are regulated during maintenance of human health by LILRB3. We need to understand the physiological role of LILRB3 to appreciate how it coordinates neutrophils in complex systems to maintain health. We need to define LILRB3 signalling to recognise how it inhibits neutrophil responses. Finally, we need to characterise the structure of LILRB3 in order to understand how it functions and how it could be targeted therapeutically. I have characterised the first LILRB3 ligand, which is a bacterial surface protein called B. Two domains within B bind LILRB3 with high-affinity and have agonistic properties. Therefore, B provides a useful experimental system to probe the biology of LILRB3. This project will provide insights into the LILRB3 physiological role on neutrophils, signalling pathways and structure, using the novel bacteria derived LILRB3 ligands identified by my group. Specifically, during this three-year project we will A) define the role of LILRB3 in neutrophil maturation, inflammation and host defence using newly developed transgenic human LILRB3 mice, B) characterise LILRB3 signalling in neutrophils, and C) resolve the structure of LILRB3, and identify new pathogen derived LILRB3 ligands.Data will provide detailed information on the role of LILRB3 in regulating neutrophil maturation, inflammation and host defence. Importantly, the project will provide the first structural information on LILRB3 and the first detailed information on LILRB3 signalling in neutrophils. The experimental resources, techniques and data will have applicability to other leukocytes, such as macrophage, and other animal systems. The long-term goal is to understand at the molecular and system level how LILRB3 coordinates neutrophilic responses during host defence, expanding our understanding of fundamental immunological processes that maintain lifelong health. It will pave the way for development of LILRB3-targetting immunotherapeutics to suppress neutrophil responses in disease situations.

中性粒细胞过度活跃与人类和动物的感染性疾病、炎症性疾病和创伤有关。中性粒细胞对于保护宿主免受病原体入侵和协调炎症至关重要。然而，如果在错误的时间、错误的地点或错误的程度被激活，它们可能会损害宿主和/或诱导严重的炎症。对于以嗜中性粒细胞驱动的炎症为特征的疾病，显然需要重新编程过度活跃反应的有效策略。抑制性受体是由人类和动物中性粒细胞表达的关键分子，其抑制中性粒细胞的活化并确保其不被过早或过度活化。它们在维持健康方面的重要性通过缺乏抑制性受体的小鼠对炎症和传染病的易感性增加来证明。靶向抑制性受体是抑制过度活跃的中性粒细胞反应的有前途的策略。然而，协调中性粒细胞调节的个体抑制性受体尚未完全了解。这是重要的，因为我们可能不知道抑制性受体为开发新的免疫抑制疗法提供的相当大的潜力。LILRB 3是在人中性粒细胞上表达的抑制性受体，其是活化、脱粒、吞噬作用和微生物杀灭的有效抑制剂。重要的是，LILRB 3在循环中性粒细胞上高度表达。这与大多数抑制性受体的低表达水平形成对比，所述抑制性受体在中性粒细胞活化时上调。因此，LILRB 3是一组独特的抑制性受体，可以靶向关闭疾病情况下的中性粒细胞动员，激活和过度反应。值得注意的是，LILRB 3的体内功能、信号传导机制和结构尚不清楚。因此，我们对中性粒细胞在LILRB 3维持人类健康期间如何调节的知识存在根本性的空白。我们需要了解LILRB 3的生理作用，以了解它如何在复杂系统中协调中性粒细胞以维持健康。我们需要定义LILRB 3信号传导，以识别它如何抑制中性粒细胞反应。最后，我们需要研究LILRB 3的结构，以了解它是如何发挥作用的，以及如何在治疗上靶向它。我已经鉴定了第一个LILRB 3配体，它是一种称为B的细菌表面蛋白。B内的两个结构域以高亲和力结合LILRB 3并具有激动性质。因此，B提供了一个有用的实验系统来探测LILRB 3的生物学。该项目将提供LILRB 3对中性粒细胞，信号通路和结构的生理作用的见解，使用由我的小组鉴定的新型细菌衍生的LILRB 3配体。具体地说，在这个为期三年的项目中，我们将A）使用新开发的转基因人LILRB 3小鼠来确定LILRB 3在中性粒细胞成熟、炎症和宿主防御中的作用，B）研究中性粒细胞中的LILRB 3信号传导，以及C）解析LILRB 3的结构，并鉴定新的病原体衍生的LILRB 3配体。数据将提供关于LILRB 3在调节中性粒细胞成熟中的作用的详细信息，炎症和宿主防御。重要的是，该项目将提供有关LILRB 3的第一个结构信息和有关中性粒细胞中LILRB 3信号传导的第一个详细信息。实验资源，技术和数据将适用于其他白细胞，如巨噬细胞，和其他动物系统。长期目标是在分子和系统水平上了解LILRB 3如何在宿主防御过程中协调嗜中性反应，扩大我们对维持终身健康的基本免疫过程的理解。它将为LILRB 3靶向免疫治疗药物的开发铺平道路，以抑制疾病情况下的中性粒细胞反应。

项目成果

Human CEACAM1 is targeted by a Streptococcus pyogenes adhesin implicated in puerperal sepsis pathogenesis.

• DOI: 10.1038/s41467-023-37732-1
• 发表时间: 2023-04-20
• 期刊: NATURE COMMUNICATIONS
• 影响因子: 16.6
• 作者: Catton, Erin A;Bonsor, Daniel A;Herrera, Carolina;Stalhammar-Carlemalm, Margaretha;Lyndin, Mykola;Turner, Claire E;Soden, Jo;van Strijp, Jos A G;Singer, Bernhard B;van Sorge, Nina M;Lindahl, Gunnar;McCarthy, Alex J
• 通讯作者: McCarthy, Alex J