Broad spectrum antifungals targeting fatty acid biosynthesis

据估计，每年有 150 万人死于侵袭性真菌感染，还有数百万人死于侵袭性真菌感染。 患有使人衰弱的粘膜和皮下真菌病。目前的抗真菌疗法存在严重的 缺陷包括疗效差、活性谱有限、患者毒性和耐药性的出现 真菌。因此，死亡率仍然居高不下，令人不安。新的和改进的治疗选择 迫切需要改善患者的治疗效果并纠正耐药性的上升。然而发现和 新药物疗法的开发仍然是一个令人沮丧的低效过程。第一阶段的目标 该提案的（R21）是应用非常规的化学筛选策略来识别生理学 脂肪酸（FA）生物合成的活性和真菌选择性抑制剂。我们的方法将重点关注脂肪酸 合酶 (FAS) 和 Ole1p FA 去饱和酶，两者具有根本不同的结构 与哺乳动物的组织和功能构成相比。 FAS 和 Ole1p 都是 对于体内感染性真菌（包括流行的人类病原体白色念珠菌）的生存至关重要 和新型隐球菌。我们建议利用这些目标来开发一类新的有效且 广谱抗真菌治疗。我们实验室开发了一种新的基于全细胞的方法，称为 Target 基于丰度的健康筛查 (TAFiS) 将用于识别白色念珠菌 FAS 的特定抑制剂 和Ole1p。该方法有利于选择与特定靶蛋白相互作用的化学探针 在完整的细胞内，从而将传统的基于靶标和细胞的筛选的优点结合到一个单一的 高通量测定。 FA 合成的抑制将通过处理后的生化分析来确认 真菌和哺乳动物细胞，以及那些具有真菌选择性活性的细胞。在第 2 阶段 (R33)，抗真菌药物 先导化合物的效力、选择性和 ADME 性质将得到优化，并且结构活性 建立的关系。所选线索的活动范围也将根据重要的信息进行测试 人类真菌病原体，并分离出对当前抗真菌药物具有抗药性的菌株。最后是生物制药， 在确定抗真菌功效之前，将评估选定先导药物的药代动力学和毒理学特性 在播散性真菌感染的小鼠模型中进行了测试。完成本研究将有助于 开发能够治愈难治性侵袭性真菌感染的新一代抗真菌药物 目前的治疗方案。

An estimated 1.5 million people die each year from invasive fungal infections, and many millions more are afflicted by debilitating mucosal and subcutaneous mycoses. Current antifungal therapies have serious deficiencies including poor efficacy, limited spectrum of activity, patient toxicity and the emergence of resistant fungi. Consequently, mortality rates have remained disturbingly high. New and improved therapeutic options are desperately needed to improve patient outcomes and redress the rise of resistance. Yet the discovery and development of new pharmocotherapies remains a frustratingly inefficient process. The objective of phase 1 (R21) of this proposal is to apply an unconventional chemical screening strategy to identify physiologically active, and fungal selective inhibitors of fatty acid (FA) biosynthesis. Our approach will focus upon fatty acid synthase (FAS) and the Ole1p FA desaturase, both of which have a fundamentally different structural organization and functional constitution compared to their mammalian counterparts. FAS and Ole1p are both essential for the viability of infectious fungi in vivo, including the prevalent human pathogens Candida albicans and Cryptococcus neoformans. We propose to exploit these targets to develop a new class of efficacious and broad spectrum antifungal therapy. A new whole-cell based approach developed within our lab termed Target Abundance based Fitness Screening (TAFiS), will be applied to identify specific inhibitors of C. albicans FAS and Ole1p. This method facilitates the selection of chemical probes that interact with a specific target protein within intact cells, thereby combining the advantages of traditional target- and cell- based screens into a single high-throughput assay. Inhibition of FA synthesis will be confirmed through biochemical analysis of treated fungal and mammalian cells, and those with fungal selective activity identified. In phase 2 (R33), the antifungal potency, selectivity and ADME properties of lead compounds will be optimized, and structure-activity relationships established. The spectrum of activity of selected leads will also be tested against important human fungal pathogens, and to isolates resistant to current antifungal drugs. Finally, the biopharmaceutic, pharmacokinetic and toxicologic properties of selected leads will be assessed before antifungal efficacy is tested in a mouse model of disseminated fungal infection. Completion of this study will facilitate the development of a new generation of antifungal drugs that can cure invasive fungal infections that are refractory to current treatment options.