Pathways underlying resistance to infection: Dysregulation of gut homeostasis by damage associate signals.

抗感染的途径：损伤相关信号导致肠道稳态失调。

• 批准号: 1917196
• 金额: --
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1917196
• 关键词: Pathways; underlying; resistance; infection; Dysregulation

The cells lining our gut, the epithelium, are a crucial barrier that protects the host from the external environment. The epithelium must be adapted to not respond to the commensal bacteria and dietary antigens it is exposed to. However the gut is a major site of pathogen entry so the gut must be able to switch from tolerance to inflammation when needed. Further, microbial colonization carries with it the risk of infection and inflammation if epithelial or immune cell homeostasis is disrupted. Dietary change, infection or antibiotics can promote release of damage associated signals (DAMPs), such as ATP, that initiate an inflammatory response. This is a similar scenario to that found in the aging population characterised by increased levels of circulating DAMPs that contribute to basal inflammatory levels. Epithelial cells are known to promote immune cell function and this interaction is crucial for mediating the change from tolerance to inflammation however little is known about this interaction in vivo. Cells sense DAMPs through a wide variety of receptors, expressed either in the membrane, like the P2X7 Receptor (P2X7R) or in the cytosol, such as the members of the NLR family (e.g. NLRP3, NLRP1). In immune cells, activation of these receptors leads to the assembly of the inflammasome, a molecular complex formed by an NLR, caspase-1 and the adaptor protein ASC, which acts as a platform for the activation of caspase-1 and the consequent secretion of the pro-inflammatory cytokines interleukin-1beta (IL-1 beta) and IL-18. However, our exciting new data suggest that epithelial cells do not respond in the same way to DAMPs as immune cells and P2X7R signalling preferentially triggers a chemokine response. The overall aim of this proposal is to determine the molecular mechanisms that regulate damage receptor signalling in epithelial and immune cells (DC) in the gut. This will be achieved using in vivo as well as in vitro approaches and techniques such as flow cytometry, western-blot, ELISA, qPCR, cell culture, gene editing CRISPR/CAs9 technology or live-cell imaging. This project has an inter-departmental supervision that embodies a multi-disciplinary approach. Specifically this project will use in vivo, ex-vivo and in vitro approaches to decipher new mechanisms by which DAMPs contribute to dysregulation of gut homeostasis. This project will also develop data analytical skills to manage and interpret biological data through data handling, statistics and experimental design.

我们肠道的上皮细胞是保护宿主免受外部环境影响的重要屏障。上皮细胞必须适应不对它所暴露的肠道细菌和饮食抗原作出反应。然而，肠道是病原体进入的主要部位，因此肠道必须能够在需要时从耐受性转变为炎症。此外，如果上皮细胞或免疫细胞稳态被破坏，微生物定殖会带来感染和炎症的风险。饮食变化、感染或抗生素可以促进损伤相关信号（DAMP）的释放，如ATP，从而引发炎症反应。这与在老龄化人群中发现的情况相似，其特征在于循环DAMP水平升高，导致基础炎症水平升高。已知上皮细胞促进免疫细胞功能，并且这种相互作用对于介导从耐受到炎症的变化至关重要，然而对体内这种相互作用知之甚少。细胞通过多种受体感知DAMP，所述受体在膜中表达，如P2 X7受体（P2 X7 R）或在胞质溶胶中表达，如NLR家族的成员（例如NLRP 3、NLRP 1）。在免疫细胞中，这些受体的活化导致炎性小体的组装，炎性小体是由NLR、半胱天冬酶-1和衔接蛋白ASC形成的分子复合物，其充当半胱天冬酶-1活化的平台，并随后分泌促炎细胞因子白细胞介素-1 β（IL-1 β）和IL-18。然而，我们令人兴奋的新数据表明，上皮细胞对DAMP的反应方式与免疫细胞不同，P2 X7 R信号传导优先触发趋化因子反应。该提案的总体目标是确定调节肠道上皮细胞和免疫细胞（DC）中损伤受体信号传导的分子机制。这将使用体内以及体外方法和技术来实现，例如流式细胞术、蛋白质印迹、ELISA、qPCR、细胞培养、基因编辑CRISPR/CAs9技术或活细胞成像。该项目有一个跨部门的监督，体现了多学科的方法。具体而言，该项目将使用体内，体外和体外方法来破译DAMP有助于肠道稳态失调的新机制。该项目还将开发数据分析技能，通过数据处理，统计和实验设计来管理和解释生物数据。