Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States.
Department of Cell and Regenerative Biology, Wisconsin Institute for Medical Research, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705, United States.
ACS Infect Dis. 2020 Dec 11;6(12):3092-3103. doi: 10.1021/acsinfecdis.0c00654. Epub 2020 Oct 30.
Enterohemorrhagic (EHEC) is the causative agent of severe diarrheal disease in humans. Cattle are the natural reservoir of EHEC, and approximately 75% of EHEC infections in humans stem from bovine products. Many common bacterial pathogens, including EHEC, rely on chemical communication systems, such as quorum sensing (QS), to regulate virulence and facilitate host colonization. EHEC uses SdiA from (SdiA), an orphan LuxR-type receptor, to sense -acyl l-homoserine lactone (AHL) QS signals produced by other members of the bovine enteric microbiome. SdiA regulates two phenotypes critical for colonizing cattle: acid resistance and the formation of attaching and effacing lesions. Despite the importance of SdiA, there is very little known about its selectivity for different AHL signals, and no chemical inhibitors that act specifically on SdiA have been reported. Such compounds would represent valuable tools to study the roles of QS in EHEC virulence. To identify chemical modulators of SdiA and delineate the structure-activity relationships (SARs) for AHL activity in this receptor, we report herein the screening of a focused library composed largely of AHLs and AHL analogues in an SdiA reporter assay. We describe the identity and SARs of potent modulators of SdiA activity, examine the promiscuity of SdiA, characterize the mechanism of a covalent inhibitor, and provide phenotypic assay data to support that these compounds can control SdiA-dependent acid resistance in . These SdiA modulators could be used to advance the study of LuxR-type receptor/ligand interactions, the biological roles of orphan LuxR-type receptors, and potential QS-based therapeutic approaches.
肠出血性大肠杆菌（EHEC）是人类严重腹泻病的病原体。牛是 EHEC 的天然宿主，人类约 75%的 EHEC 感染源自牛产品。许多常见的细菌病原体，包括 EHEC，依赖于化学通讯系统，如群体感应（QS），来调节毒力并促进宿主定植。EHEC 使用 SdiA 从 （SdiA），一种孤儿 LuxR 型受体，来感知 -酰基 l-高丝氨酸内酯（AHL）QS 信号，这些信号由牛肠道微生物组的其他成员产生。SdiA 调节两个对牛定植至关重要的表型：酸抗性和附着和消蚀病变的形成。尽管 SdiA 非常重要，但人们对其对不同 AHL 信号的选择性知之甚少，也没有报道过专门作用于 SdiA 的化学抑制剂。这些化合物将成为研究 QS 在 EHEC 毒力中的作用的有价值的工具。为了鉴定 SdiA 的化学调节剂并描绘该受体中 AHL 活性的结构-活性关系（SARs），我们在此报告了在 SdiA 报告测定中筛选主要由 AHL 和 AHL 类似物组成的聚焦文库。我们描述了 SdiA 活性的有效调节剂的身份和 SARs，检查了 SdiA 的混杂性，表征了共价抑制剂的机制，并提供了表型测定数据来支持这些化合物可以控制 中的 SdiA 依赖性酸抗性。这些 SdiA 调节剂可用于推进 LuxR 型受体/配体相互作用、孤儿 LuxR 型受体的生物学作用以及潜在的基于 QS 的治疗方法的研究。
