DictyMyc: Using Dictyostelium to study the genetic basis of Mycobacterium bovis intracellular infection.

DictyMyc：利用盘基网柄菌来研究牛分枝杆菌细胞内感染的遗传基础。

• 批准号: NC/M002012/1
• 负责人: Graham Stewart
• 金额: $ 55.41万
• 依托单位: University of Surrey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2015
• 资助国家: 英国
• 起止时间: 2015 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NC%2FM002012%2F1
• 关键词: DictyMyc; Using; Dictyostelium; study; genetic

Bovine tuberculosis (TB) caused by Mycobacterium bovis is one of the most important veterinary health problems in the UK. In the absence of improved control, the projected economic burden to the UK over the next decade is predicted to be £1 billion. Control is likely to require an integrated approach with vaccination of cattle representing a key component. Presently there is no licensed vaccine against bovine TB. However, the live M.bovis BCG vaccine, presently used against human TB, represents an encouraging vaccination option, yet studies suggest that it only provides protection to ~70% of animals.To form a rational platform from which to design an improved vaccine that stimulates protective immunity in all individuals, we propose it is necessary to better understand the basic mechanisms of the host-pathogen interaction during mycobacterial infection. Evidence suggests that manipulating the mycobacterial interaction with phagocytic cells can increase immunogenicity.The central feature of mycobacterial infection is an ability to replicate inside mammalian immune cells called phagocytes. We and others have previously studied the bacterial genes involved in these processes. However, analysis of the HOST genes involved in the interactions has been difficult because it is hard to manipulate the genetics of mammalian cells. One solution is to use phagocytes from genetically modified- (GM-) mice which are becoming more widely used in research.THE AIM OF THIS PROJECT IS TO DEVELOP AND CHARACTERISE NON-VERTEBRATE MODELS OF MYCOBACTERIAL INFECTION AS A REPLACEMENT FOR USING PHAGOCYTES FROM GM-MICE. In this project we propose to use the free living amoebae Dictyostelium discoideum as a model phagocyte because it is easy to manipulate its genetics, and mycobacteria are able to survive in dictyostelium in a similar way to how they survive in phagocytes. Thus experiments in which dictyostelium is infected with mycobacteria provide a way to easily study both the host and pathogen genes during mycobacterial infection whilst avoiding the use of sentient animals. To characterise the Dictyostelium model systems and validate them against bovine infection, we will compare the bacterial genes used in infection in bovine macrophages with those required for infection in dictyostelium. We will also use a newly developed technology that will allow the simultaneous analysis of a library of 40,000 dictyostelium (host) mutants during mycobacterial infection. Our experiments will comprehensively identify which host and pathogen genes are involved in the M.bovis survival in dictyostelium informing how the mycobacterium controls its host cell and providing information to help design a better vaccine against bovine and human TB. This project will provide the technology and evidence to justify other researchers working on tuberculosis and other infectious diseases to utilise dictyostelium as a model organism.

由牛分枝杆菌引起的牛结核病是英国最重要的兽医健康问题之一。在没有改善控制的情况下，预计英国在未来十年的经济负担将达到10亿英镑。控制可能需要一种综合的方法，其中牛的疫苗接种是一个关键组成部分。目前还没有获得许可的牛结核病疫苗。然而，目前用于人类结核病的牛分枝杆菌卡介苗是一种令人鼓舞的疫苗接种选择，但研究表明，它只对~70%的动物提供保护。为了形成一个合理的平台，以此为基础设计一种增强所有个体保护性免疫的疫苗，我们建议有必要更好地了解分枝杆菌感染过程中宿主与病原体相互作用的基本机制。有证据表明，控制分枝杆菌与吞噬细胞的相互作用可以提高免疫原性。分枝杆菌感染的主要特征是能够在哺乳动物免疫细胞内复制，称为吞噬细胞。我们和其他人之前已经研究了参与这些过程的细菌基因。然而，分析参与相互作用的宿主基因一直很困难，因为很难操纵哺乳动物细胞的遗传学。一种解决方案是使用转基因(GM-)小鼠的吞噬细胞，该研究越来越广泛地使用转基因小鼠的吞噬细胞。该项目的目的是开发和表征分枝杆菌感染的非脊椎动物模型，以替代使用转基因小鼠的吞噬细胞。在这个项目中，我们建议使用自由生活的阿米巴Dictyostelialdiscoideum作为吞噬细胞的模型，因为它很容易操纵它的遗传学，而且分枝杆菌能够以类似于它们在吞噬细胞中生存的方式在Dictyostelium中生存。因此，用分枝杆菌感染网柄基菌的实验提供了一种方法，可以在分枝杆菌感染期间轻松地研究宿主和病原体基因，同时避免使用有知觉的动物。为了描述Dictyostelius模型系统的特征并验证它们对牛的感染，我们将比较感染牛巨噬细胞所用的细菌基因和Dictyostelius感染所需的那些细菌基因。我们还将使用一项新开发的技术，该技术将允许在分枝杆菌感染期间同时分析40,000个Dictyostelials(宿主)突变体的文库。我们的实验将全面地确定哪些宿主和病原体基因参与了牛分支杆菌在Dictyostelials中的生存，揭示了分枝杆菌如何控制其宿主细胞，并为设计更好的牛和人类结核病疫苗提供了信息。该项目将提供技术和证据，证明其他从事结核病和其他传染病工作的研究人员可以利用网盘基菌作为模式生物。