Targeting type II secretion, a common virulence pathway

抗生素耐药性是一个迫在眉睫的全球问题，威胁着上个世纪一些最重要的公共卫生成果。这一严重的健康挑战，加上生物制剂的新威胁，要求确定和开发治疗细菌感染的新战略。靶向细菌毒力系统，如细胞外分泌途径，是传统抗生素疗法的一种有吸引力的治疗替代方案，因为它可以在不杀死病原体的情况下减弱病原体，可能会减少耐药性的出现。 II型分泌系统(T2S)广泛分布于革兰氏阴性病原体中，能分泌多种毒素和降解酶，是治疗干预的理想靶点。它由跨越整个细胞膜的多蛋白复合体组成，包括细胞质中的ATPase，延伸到周质间的内膜亚复合体，以及外膜上的分泌孔。由于这些组件中有几个是TIS独有的，因此它们提供了不同的潜在目标 新的抗菌药物。 乔氏弧菌是具有T2S系统的研究最充分的病原体，因此，I3非常适合高通量筛选T2S小分子抑制剂的化学库。霍乱弧菌中T2S系统的化学灭活可能会导致与遗传灭活类似的缺陷，阻止霍乱毒素和其他潜在毒力因子的分泌，防止在胃肠道定植。使用几种独特的工具、试剂和检测方法，包括一种适合于 HTS，我们将分离出通过T2S系统阻断分泌的合成化合物。结构、生化和体内资源的可获得性将使我们能够分析已识别的抑制剂的作用机制。 尽管HTS方法不需要T2S复合体的事先结构知识，但关于该机制的结构和功能的信息对于确定抑制物靶标(S)和最终开发临床有用的药物是必不可少的。

Antibiotic resistance is a looming global problem threatening some of the most significant public health gains of the past century. This critical health challenge, together with the emerging threat of biowarfare agents calls for the identification and development of new strategies for the treatment of bacterial infections. Targeting bacterial virulence systems, such as extracellular secretion pathways, is an attractive therapeutic alternative to conventional antibiotic therapy since it attenuates the pathogens without killing them possibly reducing the emergence of drug resistance. The type II secretion (T2S) system is widely distributed among gram-negative pathogens where it secretes a variety of toxins and degradative enzymes, making it an ideal target for therapeutic intervention. It consists of a multiprotein complex that spans the entire cell envelope, including an ATPase in the cytoplasm, an inner membrane subcomplex that extends into the periplasmic compartment, and a secretion pore in the outer membrane. Since several of these components are unique to TIS, they provide distinct potential targets for novel antibacterial drugs. Vibrio choferae is the most well studied pathogen with a T2S system and, as such, i3 well suited for high throughput screening (HTS) of chemical libraries for small molecule inhibitors of T2S. Chemical inactivation of the T2S system in V. cholerae is likely to result in similar defects as genetic inactivation, blocking secretion of cholera toxin and other potential virulence factors and preventing colonization In the gastro-intestinal tract. Using several unique tools, reagents and assays including a protease secretion assay that is amenable to HTS, we will isolate synthetic compounds that block secretion via the T2S system. The availability of structural, biochemical and in vivo resources will enable us to analyze the mechanism of action of identified Inhibitors. Although the HTS approach does not require prior structural knowledge of the T2S complex, information on the structure and function of this machinery is indispensable for the identification of inhibitor target(s), and for the final development of clinically useful agents.