Characterizing the role of new host components for the intracellular proliferation and survival of Salmonella enterica

细菌病原体显著改变宿主细胞功能，以克服先天和获得性免疫反应，并在宿主细胞内建立一个生态位。在这些复杂的宿主-病原体相互作用过程中，病原体迫使宿主将它们安置在所谓的含菌室（bcc）中。为了形成bcc，细菌分泌改变正常细胞功能的蛋白质，包括信号通路或囊泡运输控制。这些被破坏的宿主功能随后放弃其正常作用，支持BCC的发展，并通过提供营养和保护来促进细菌生长。这些隔室的形成和成熟是复杂的，只有部分细菌和宿主之间潜在的相互作用被理解。最近，我们开发了一种新的基于质谱的方法来筛选肠沙门氏菌血清型鼠伤寒沙门氏菌（一种常见的食源性病原体）中bcc的组成。我们研究的一个关键发现是，沙门氏菌操纵的宿主功能比以前预期的要多，包括那些被认为只有其他细菌才能利用的细胞器。该项目旨在建立在这些见解的基础上，并将开发和实施方法来揭示宿主和微生物之间串扰的分子机制。从长远来看，我们将更全面地了解所涉及的分子靶点，探索迄今为止未知的相互作用，并确定可能被细菌优先靶向的关键宿主机制。这些发现有望为宿主和微生物之间的共同进化军备竞赛提供机制上的见解。在短期内，我们的目标是调查沙门氏菌和HeLa细胞之间新发现的相互作用的性质。新的宿主成分的敲除实验将揭示它们对沙门氏菌bcc的形成和组成的重要性。从这些改变的BCC中分离出的沙门氏菌的蛋白质组分析将表明该细菌是否因BCC组成的变化而面临不同的营养挑战。我们将进一步进行相互作用研究，以确定参与劫持新宿主成分的细菌蛋白质。总之，这项工作将扩大我们对沙门氏菌与宿主相互作用的基本理解，并提供沙门氏菌如何在各种宿主生物和细胞类型中生存的见解。通过了解沙门氏菌能够适应不同细胞内条件的策略，就有可能制定干预策略，以防止牲畜和人类感染，从而提高食品安全。

Bacterial pathogens dramatically alter host cell function to overcome innate and acquired immune responses and to establish a niche inside host cells. During these complex host-pathogen interactions, pathogens force their hosts to accommodate them in so-called bacterium-containing compartments (BCCs). To form BCCs, bacteria secrete proteins that alter normal cellular functions including signaling pathways or vesicle trafficking control. These subverted host functions then abandon their regular role and support the development of the BCC and promote bacterial growth by providing nutrition and protection. The formation and maturation of these compartments is complex and only parts of the underlying interactions between bacteria and host are understood. Recently, we developed a novel mass spectrometry-based method to tease out the composition of BCCs in Salmonella enterica serovar Typhimurium, a common food-borne pathogen. A key finding of our study was that Salmonella is manipulating more host functions than previously anticipated, including organelles that were believed to be utilized only by other bacterial species. This program intends to build on these insights and will develop and implement methods to reveal the molecular mechanisms underlying the crosstalk between host and microbe. Over the long term we will gain a more complete view of the involved molecular targets, explore hitherto unknown interactions and identify key host mechanisms that may be preferentially targeted by bacteria. These findings are expected to provide mechanistic insights into the co-evolutionary arms race between host and microbes. In the short term, our goals are to investigate the nature of the newly identified interactions between Salmonella and HeLa cells. Knockdown experiments of the novel host components will reveal their importance for the formation and composition of Salmonella BCCs. Proteome analysis of Salmonella isolated from these altered BCCs will indicate whether the bacterium faces different nutritional challenges as a consequence of BCC composition changes. We will further perform interaction studies to identify the bacterial proteins involved in hijacking the novel host components. Together, the work will expand our fundamental understanding of Salmonella-host interactions and provide insights how Salmonella can reside in a variety of host organism and cell types. By understanding those strategies with which Salmonella can adapt to different intracellular conditions it may be possible to develop intervention strategies to prevent infection of livestock and humans and thereby improve food safety.