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.

项目总结/摘要 医学相关微生物的内在和获得性耐药性对人类构成了严重威胁 健康，并在全球范围内产生巨大的经济后果。真菌病原体呈现出一种特殊的 挑战，因为它们是真核生物，与人类宿主有许多相同的生物过程 他们感染。其中最普遍的真菌病原体是隐球菌属的物种， 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， 死亡率，如果不治疗。即使使用最好的治疗方法，死亡率仍高达35-40%。 因为在真菌中具有不同靶点的药物种类的数量非常有限， 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- 坡度阻力迫切需要新的、非交叉反应的治疗干预靶点。 在以前的工作中，我们发现分子伴侣Hsp 90调节耐药性， 念珠菌属和曲霉属真菌的毒力。在这些病原体中靶向Hsp 90有望 提供了一个强有力的策略，以提高抗真菌药物的疗效和消除耐药性，但 Hsp 90在致病性隐球菌中的作用还未被研究。Hsp 90的“药物性”已经被 通过许多靶向这种蛋白质的小分子来治疗人类癌症。的 目前可用的药物在真菌感染的情况下抗真菌活性差且可能具有毒性，然而， 要求开发真菌选择性Hsp 90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-末端结构域的结构 白色念珠菌Hsp 90，并确定了一个口袋的核苷酸结合区，大于其 人类对应物，并在隐球菌中保守。在这种洞察力的指导下，我们设计，合成和 表征了真菌Hsp 90的两种先导抑制剂，相对于人蛋白质具有>10倍的选择性。现在我想， 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 在真菌生物学（考恩），化学（布朗）和药理学/实验的补充专业知识 治疗学（Whitesell），对其他类似物文库进行构效关系（SAR）研究 并产生选择性药物样探针。这些将被用于一个强大的基因和 药理学方法来剖析Hsp 90在隐球菌的耐药性和毒力中的作用。在 除了将获得的重要基本见解外，我们的结果可能会影响治疗。 侵袭性真菌感染在不久的将来，通过提供有前途的药物开发线索 候选人在一个完全未开发的目标空间运作。