Targeting Hsp90 in cryptococcal fungal pathogenesis

隐球菌真菌发病机制中的靶向 Hsp90

• 批准号: 9171395
• 负责人: Lauren Elaine Brown
• 金额: $ 80.44万
• 依托单位: UNIVERSITY OF TORONTO
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-15 至 2020-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9171395
• 关键词: Affinity; Animals; Antifungal Agents; Aspergillus; Azole resistance; Azoles; Binding; Biochemical; Biological; Biological Assay; Biological Process; Biology; Candida; Candida albicans; Cell Communication; Cells; Cessation of life; Chemicals; Chemistry; Clinical; Complement; Coupled; Cryptococcal Meningitis; Cryptococcus; Cryptococcus gattii; Cryptococcus neoformans; Cryptococcus neoformans infection; Development; Disease; Disease Outbreaks; Diversity Library; Dose-Limiting; Drug Kinetics; Drug resistance; Economics; Eukaryota; Fluorescence Polarization; Fungal Drug Resistance; Future; Genetic; Goals; HIV; Health; Heat-Shock Proteins 90; Human; Immunocompromised Host; In Vitro; Individual; Industrial fungicide; Infection; Investigational Therapies; Lead; Left; Libraries; Malignant Neoplasms; Measures; Medical; Melanins; Molecular; Molecular Chaperones; Mus; Mycoses; N-terminal; Natural Products; Nucleotides; Organ Transplantation; Organism; Oximes; Pacific Northwest; Pathogenesis; Pharmaceutical Preparations; Pharmacology; Production; Proteins; Resistance; Resources; Role; Route; Sepsis; Specificity; Stress; Structure; Structure-Activity Relationship; System; Testing; Therapeutic; Therapeutic Intervention; Toxic effect; Virulence; Work; abstracting; acquired drug resistance; analog; base; brain endothelial cell; burden of illness; cancer therapy; capsule; clinical care; design; drug candidate; drug metabolism; effective therapy; frontier; fungus; immune function; improved; in vivo; inhibitor/antagonist; insight; macrophage; microorganism; monorden; mortality; mouse model; multidisciplinary; novel; pathogen; promoter; small molecule; targeted treatment; tool; trait

Project Summary/Abstract Intrinsic and acquired drug resistance of medically relevant microorganisms poses a grave threat to human health and has enormous economic consequences worldwide. Fungal pathogens present a particular challenge because they are eukaryotes and share many of the same biological processes as the human hosts they infect. Among the most pervasive fungal pathogens are species of Cryptococcus, which cause over 600,000 deaths per year. Cryptococcal meningitis, the major clinical manifestation of the disease, has a 100% mortality rate if left untreated. Even with the best available therapies, mortality rates remain high at 35-40% because the number of drug classes that have distinct targets in fungi is very limited and the usefulness of current antifungal drugs is compromised by either dose-limiting host toxicity or the frequent emergence of high- grade resistance. New, non-cross-reactive targets for therapeutic intervention are urgently needed. In previous work, we discovered that that the molecular chaperone Hsp90 regulates drug resistance and virulence in species of the fungi Candida and Aspergillus. Targeting Hsp90 in these pathogens promises to provide a powerful strategy to enhance the efficacy of antifungal drugs and abrogate drug resistance, but the role of Hsp90 in pathogenic cryptococcal species remains unexplored. The “druggability” of Hsp90 has been well established by the many small molecules targeting this protein for the treatment of human cancers. The poor antifungal activity and likely toxicity of currently available drugs in the setting of fungal infection, however, demand the development of fungal-selective Hsp90 inhibitors. To pursue the goal of fungal selectivity, our interdisciplinary team solved the structure of the N-terminal domain of Candida albicans Hsp90, and identified a pocket in the nucleotide-binding region that is larger than its human counterpart and is conserved in Cryptococcus. Guided by this insight, we designed, synthesized and characterized two lead inhibitors of fungal Hsp90 with >10-fold selectivity relative to the human protein. Now, leveraging the novel chemistry and structure-based design approach we have developed, we will use our complementary expertise in fungal biology (Cowen), chemistry (Brown), and pharmacology/experimental therapeutics (Whitesell) to pursue structure activity relationship (SAR) studies on libraries of additional analogs and generate selective drug-like probes. These will be used in a powerful combination of genetic and pharmacological approaches to dissect Hsp90's role in the drug resistance and virulence of Cryptococcus. In addition to the important basic insights that will be obtained, our results are likely to impact the treatment of invasive fungal infections in the near future by providing promising leads for the development of drug candidates that operate in a completely unexploited target space.

项目概要/摘要 医学相关微生物的内在和获得性耐药性对人类构成严重威胁 健康并在全世界范围内产生巨大的经济后果。真菌病原体具有特殊的 挑战，因为它们是真核生物，并且与人类宿主有许多相同的生物过程 他们感染。最普遍的真菌病原体是隐球菌属，它会导致超过 每年有 60 万人死亡。隐球菌性脑膜炎是该病的主要临床表现，发病率为 100% 如果不治疗的话死亡率。即使采用最好的治疗方法，死亡率仍然高达 35-40% 因为在真菌中具有不同靶点的药物类别的数量非常有限，并且 目前的抗真菌药物受到剂量限制性宿主毒性或频繁出现的高致死率的影响。 级电阻。迫切需要新的、非交叉反应的治疗干预目标。 在前期工作中，我们发现分子伴侣Hsp90可调节耐药性和 真菌念珠菌和曲霉菌的毒力。针对这些病原体中的 Hsp90 有望 为增强抗真菌药物的疗效和消除耐药性提供了强有力的策略，但 Hsp90 在致病性隐球菌物种中的作用仍有待探索。 Hsp90 的“成药性” 许多针对这种蛋白质的小分子已被广泛应用于治疗人类癌症。这 然而，目前可用的药物在真菌感染的情况下抗真菌活性较差且可能具有毒性， 需要开发真菌选择性 Hsp90 抑制剂。 为了追求真菌选择性的目标，我们的跨学科团队解决了N端结构域的结构 白色念珠菌 Hsp90，并鉴定出核苷酸结合区中的一个口袋，该口袋大于其 人类对应物并在隐球菌中保守。在这一见解的指导下，我们设计、综合并 表征了真菌 Hsp90 的两种主要抑制剂，相对于人类蛋白质，其选择性超过 10 倍。现在， 利用我们开发的新颖的化学和基于结构的设计方法，我们将使用我们的 真菌生物学（Cowen）、化学（Brown）和药理学/实验方面的互补专业知识 Therapeutics (Whitesell) 对其他类似物库进行结构活性关系 (SAR) 研究 并产生选择性的药物样探针。这些将被用于遗传和 药理学方法剖析 Hsp90 在隐球菌耐药性和毒力中的作用。在 除了将获得的重要的基本见解之外，我们的结果可能会影响治疗 通过为药物开发提供有希望的线索，在不久的将来研究侵袭性真菌感染 在完全未开发的目标空间中操作的候选者。