Chemically diverse antimicrobials from silent biosynthetic pathways

描述（由申请人提供）：医疗保健相关感染（HAI）对美国人民的个人和经济福祉构成巨大威胁。在过去的十年中，由于几个复合因素（例如，微生物耐药性水平的增加、免疫功能低下患者数量的增加以及新抗菌剂产量的急剧下降）。因此，迫切需要开发新的抗真菌和抗细菌治疗剂以阻止HAI引起的人类生命损失。不幸的是，许多现代药物筛选程序依赖于化学贫乏的图书馆，严重损害其各自的铅发现潜力。许多这些化学库的主要缺点是化合物同质性的显著程度和它们的组分化合物之间缺乏结构新奇性。本申请的目的是使用化学表观遗传学方法来严格检查真菌中由沉默生物合成途径编码的独特次级代谢产物作为新型抗菌剂的来源。我们将测试中心假设，即真菌中沉默的天然产物基因簇的激活将提供无与伦比的化学多样性次级代谢产物，我们将使用这些次级代谢产物来采购新的抗菌和抗真菌药物。研究用于生产抗菌剂的沉默生物合成途径的基本原理是，从该来源产生的次级代谢产物预计在结构和功能上是新颖的;因此，预计这些化合物具有重要的药物开发价值。根据我们研究小组的初步数据，我们设计了三个具体目标来检验中心假设：1）研究在化学表观遗传修饰后从真菌中出现的抗微生物活性的范围，2）使用生物测定引导的微孔板分级分离与电喷雾电离飞行时间质谱法串联，以去复制和纯化生物活性天然产物，用于针对一组微生物病原体的测试，以及3）应用生物系统和半合成技术的组合来探测先前在PI的实验室中发现的两组独特的抗菌先导物的结构-活性特征。这项研究意义重大，因为它利用了一种创新的方法，化学表观遗传学，从真菌中获得神秘的天然产物。这些化合物代表了具有突出治疗应用的生物活性有机分子的未开发来源。预计这些研究将提供一系列化学上前所未有的天然产物，这些天然产物将具有极好的铅开发潜力，作为未来NIH赞助研究的一部分。

DESCRIPTION (provided by applicant): Healthcare-associated infections (HAIs) pose a tremendous threat to the personal and financial wellbeing of the American people. Over the last decade, there has been a surge in mortality due to HAIs as a result of several compounding factors (e.g., increased levels of drug resistance among microbes, escalating numbers of immunocompromised patients, and a sharp decline in the production of new antimicrobials). Consequently, there is a critical need for the development of new antifungal and antibacterial therapeutics to stem the loss of human life caused by HAIs. Unfortunately, many modern drug screening programs rely on chemically impoverished libraries that severely compromise their respective lead discovery potentials. A major shortcoming for many of these chemical libraries is the significant degree of compound homogeneity and a lack of structural novelty among their component compounds. The objective of this application is to use a chemical-epigenetics methodology to critically examine the unique secondary metabolites that are encoded by silent biosynthetic pathways in fungi as a source of novel antimicrobials. We will test the central hypothesis that the activation of silent natural-product gene clusters in fungi will provide unparalleled access to chemically diverse secondary metabolites, which we will use for procuring new antibacterial and antifungal leads. The rationale for investigating silent biosynthetic pathways for the production of antimicrobials is that secondary metabolites emerging from this source are expected to be structurally and functionally novel; thus these compounds are anticipated to have significant drug development value. Based on our research group's strong preliminary data, three specific aims have been designed to test the central hypothesis: 1) investigate the range of antimicrobial activities emerging from fungi following chemical-epigenetic modification, 2) use bioassay-guided microplate fractionation in tandem with electrospray-ionization time-of-flight mass spectrometry to dereplicate and purify bioactive natural products for testing against a panel of microbial pathogens, and 3) apply a combination of biosystematic and semisynthetic techniques to probe the structure- activity features of two unique groups of antimicrobial leads previously discovered in the PI's laboratory. This research is significant because it capitalizes on an innovative methodology, chemical epigenetics, to access cryptic natural products from fungi. These compounds represent an untapped source of bioactive organic molecules with outstanding therapeutic applications. It is anticipated that these studies will provide an array of chemically unprecedented natural products that will have superb lead development potential as part of future NIH-sponsored studies.