Synthetic Ligands for Modulating Bacterial Communication

描述（由申请人提供）：该项目的总体目标是设计，合成和评估调节细菌细胞-细胞通讯机制的新型化学诱导剂。细菌相互沟通和作为一个群体发挥作用的能力在传染病的发展中是至关重要的。革兰氏阴性细菌使用小分子（或自诱导剂）及其同源蛋白受体的化学“语言”来感知其局部种群密度，这种现象被称为“群体感应”。在高种群密度下，致病菌利用这种感应机制组织成称为生物膜的结构群落，并激活毒力途径，这是无数慢性感染的基础。控制细菌群体感应和减少生物膜形成的方法的发展将对人类健康产生重大影响。我们假设合成配体可以用来阻断细菌自诱导剂/受体的结合，调节群体感应和生物膜的形成。这一策略将使我们能够解决细菌交流领域的基本问题。首先，我们发现的配体将揭示小分子促进或抑制群体感应所必需的分子水平特征。其次，人工合成的配体可以用来探测自诱导剂受体激活和失活的构象要求。第三，量身定制的高亲和力配体将使许多顽固的自诱导剂受体得以分离。我们已经开发了一种方法来解决这些问题，该方法集成了合成有机、组合和生物物理化学技术，以快速识别调节细菌群体感应的新分子。本研究有三个具体目的：(1)设计和合成针对细菌自诱导剂受体的新配体；(2)测试合成的配体对相关致病菌群体感应的影响；(3)利用现代生物物理技术表征非天然配体与自诱导剂受体的结合相互作用。我们已经通过合成和鉴定一组新的群体感应小分子拮抗剂在我们的初步研究中验证了这种方法。相关性：细菌利用化学信号引发大多数人类感染。阻断这些信号通路的方法的发现将对公共卫生产生深远的影响。全球迫切需要新的抗微生物疗法；通过阻断细菌通讯网络干扰细菌毒力的能力代表了一种全新的治疗方法，在临床上是及时的。

DESCRIPTION (provided by applicant): The broad goal of this project is the design, synthesis, and evaluation of new chemical inducers that modulate cell-cell communication mechanisms in bacteria. The ability of bacteria to communicate with themselves and function as a group is crucial in the development of infectious disease. Gram-negative bacteria use a chemical 'language' of small molecules (or autoinducers) and their cognate protein receptors to sense their local population densities in a phenomenon known as 'quorum sensing'. At high population densities, pathogenic bacteria use this sensing mechanism to organize into structured communities called biofilms and activate virulence pathways that are the basis for myriad chronic infections. The development of methods to control bacterial quorum sensing and attenuate biofilm formation would have a major impact on human health. We hypothesize that synthetic ligands can be used to intercept bacterial autoinducer/ receptor binding and modulate quorum sensing and biofilm formation. This strategy would allow us to address fundamental questions in the field of bacterial communication. First, the ligands we uncover will reveal the molecular level features that are essential for small molecule promotion or suppression of quorum sensing. Second, synthetic ligands could be used to probe the conformational requirements for autoinducer receptor activation and inactivation. Third, tailored higher affinity ligands would enable isolation of the numerous recalcitrant autoinducer receptors. We have developed an approach to address these questions that integrates synthetic organic, combinatorial, and biophysical chemistry techniques to rapidly identify new molecules that modulate quorum sensing in bacteria. The proposed research has three Specific Aims: (1) To design and synthesize new ligands that target bacterial autoinducer receptors, (2) To test the effects of the synthetic ligands on quorum sensing in relevant pathogenic bacteria, and (3) To characterize the binding interactions of non-native ligands with autoinducer receptors using modern biophysical techniques. We have validated this approach in our preliminary studies through the synthesis and identification of a set of new small molecule antagonists of quorum sensing. Relevance: Bacteria use chemical signals to initiate the majority of human infections. The discovery of methods to block these signaling pathways would have a profound impact on public health. There is an urgent, global need for new antimicrobial therapies; the ability to interfere with bacterial virulence by intercepting bacterial communication networks represents a completely new therapeutic approach and is clinically timely.