Infection-Dependent Vulnerabilities of Gram-negative Bacterial Pathogens

摘要 该项目的更大目标是确定革兰氏阴性细菌依赖感染的弱点 可以通过化学手段利用的病原体。我们关注的是人类病原体肠炎沙门氏菌血清型 鼠伤寒沙门氏菌及其在哺乳动物细胞内的存活和细胞培养感染模型 和小分子作为工具。我们和其他人观察到一些不起作用的小分子 对抗介质中的革兰氏阴性菌，防止病原体在细胞和动物感染期间存活。 革兰氏阴性细菌可能在感染小分子时变得脆弱，因为各种宿主 先天免疫机制渗透细菌细胞膜和/或占据外排泵，使 达到周质或细胞靶点的化合物。当实验室培养基模仿宿主的先天免疫时 这些化合物透过外膜，抑制细菌生长。我们发现了斯莫尔 在肉汤条件下渗透外膜或在原生质体中的分子，消散 细菌内膜电压，而不会对脂质双层造成物理破坏。膜电压击穿 例如，通过干扰能量产生和/或激活压力来破坏细菌- 响应信号。这些化合物不会在杀死S.的浓度下破坏哺乳动物的细胞膜。 巨噬细胞中的鼠伤寒沙门氏菌和至少一种化合物减少了小鼠的组织定植， 在体内展示了这种方法的潜力。具体的目标将审问五个不同的分子 类来确定是否应将瞄准内膜作为一种新的战斗方法 革兰氏阴性细菌感染。

SUMMARY The larger goal of the project is to identify infection-dependent weaknesses of Gram-negative bacterial pathogens that could be exploited chemically. We focus on the human pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) and its survival within mammalian cells and use cell culture infection models and small molecules as tools. We and others have observed that some small molecules that are not effective against Gram-negative bacteria in media prevent pathogen survival during infection of cells and animals. Gram-negative bacteria likely become vulnerable during infection to small molecules because a variety of host innate immune mechanisms permeabilize the bacterial cell envelope and/or occupy efflux pumps, enabling compounds to reach a periplasmic or cellular target. When laboratory media imitates host innate immunity by permeabilizing the outer membrane, these compounds inhibit bacterial growth. We have identified small molecules that under broth conditions that permeabilize the outer membrane or in protoplasts, dissipate bacterial inner membrane voltage without physically disrupting the lipid bilayer. Membrane voltage disruption could compromise bacteria by, for instance, interfering with energy production and/or activating stress- response signaling. The compounds do not disrupt mammalian membranes at concentrations that kill S. Typhimurium in macrophages and at least one of the compounds reduces tissue colonization in mice, demonstrating in vivo potential for this approach. The Specific Aims will interrogate five distinct molecule classes to determine whether targeting the inner membrane should be pursued as a novel approach to fighting Gram-negative bacterial infections.