Inhibiting sequential biosynthetic steps of a fungal-specific organelle

抑制真菌特异性细胞器的连续生物合成步骤

• 批准号: 10617178
• 负责人: Lori Ferrins
• 金额: $ 44.54万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-15 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10617178
• 关键词: Affect; Affinity; Amphotericin; Anabolism; Antibiotics; Antifungal Agents; Biochemistry; Biological; Biological Assay; Candida; Candida albicans; Candida auris; Candidiasis; Cell Wall; Cell physiology; Cells; Cessation of life; Chemicals; Combined Antibiotics; Complex; Cotrimoxazole; Defect; Development; Disease; Drug Targeting; Elements; Equilibrium; Funding; Genetic; Glucans; Glucose; Glucosyltransferase; Goals; Growth; Homeostasis; Homologous Gene; Hospitalization; Human; Hypersensitivity; Immunocompromised Host; Individual; Infection; Inorganic Phosphate Transporter; Libraries; Link; Micafungin; Mucorales; Mycoses; Nucleotides; Nutritional; Organelles; Outcome; Oxidative Stress; Patients; Pharmaceutical Chemistry; Pharmaceutical Preparations; Phenotype; Polymers; Process; Production; Resistance; Signal Transduction; Sirolimus; Specificity; Stress; Sulfamethoxazole; System; Tetrahydrofolates; Toxic effect; Trimethoprim; Trimethoprim-Sulfamethoxazole; United States; Uridine Diphosphate; Validation; Virulence; Work; antimicrobial; attributable mortality; chemical genetics; clinical care; design; drug development; drug discovery; emerging pathogen; experience; fitness; fungus; glucan synthase; high throughput screening; inhibitor; inorganic phosphate; invention; metabolomics; microbial; monomer; novel; novel therapeutics; optimal treatments; pathogenic fungus; pharmacologic; response; screening; sugar nucleotide

PROJECT SUMMARY/ABSTRACT Candida albicans is the most frequently isolated fungus causing invasive disease in the United States. These infections are dreaded complications of serious illnesses, especially in hospitalized or immunocompromised patients. C. albicans infections are challenging to eradicate, and are still estimated to lead to death in 20% of the affected patients. Currently only 3 classes of antifungal drugs are available to treat invasive fungal infections. Antifungal drug development is difficult because of the similarity between fungal and human cells, which leads to unacceptable toxicity of many compounds that damage or kill fungi. Developing antifungal agents whose targets are absent in human cells would circumvent this difficulty. Increasing potency of antifungal drugs could also lead to better outcomes. A paradigm for increased antimicrobial potency is the important combination antibiotic Cotrimoxazole, whose two components target sequential steps in the biosynthesis of tetrahydrofolate. The goal of this proposal is to find compounds that can be developed into specific inhibitors of two cellular processes unique to fungi, whose combination could give rise to a more potent antifungal agent. Two fungal cellular processes that are fundamentally different or absent in humans are phosphate homeostasis and cell wall construction. We previously found that the major C. albicans high-affinity phosphate transporter Pho84 is required for normal nutritional (Target of Rapamycin-) signaling, cell wall stress- and oxidative stress resistance, hyphal growth and virulence. Since humans manage their phosphate balance completely differently from fungi, blocking Pho84 is not predicted to impact human cellular functions. Pho84 is highly conserved across the fungal kingdom, including in emerging pathogens like Candida auris. Cells that lack Pho84 contain diminished concentrations of nucleotides, whose production requires ample intracellular phosphate supplies, and of their downstream metabolites, nucleotide sugars. Nucleotide sugars are precursors for biosynthesis of the major cell wall polymers. We propose to take advantage of this defect to sequentially perturb major steps in cell wall biosynthesis by combining inhibition of Pho84 with inhibition of glucan biosynthesis. To do this, we established a novel high-throughput assay system to detect specific inhibitors of these fungal targets. We will prioritize hit compounds according to their biological effects in virulence-associated or essential cellular processes, and according to their chemical features. This work will lay the ground to apply the paradigm of stepwise inhibition of a critical biosynthetic process to antifungal drug development. The proposal is intended to select screen hits that meet defined biological and medicinal chemistry criteria for further development.

项目摘要/摘要 白色念珠菌是在美国引起侵袭性疾病的最常见的分离真菌。 这些感染是严重疾病的可怕并发症，尤其是在住院或 免疫功能受损的病人。白念珠菌感染很难根除，据估计， 导致20%的受影响患者死亡。目前只有3类抗真菌药物可供选择 治疗侵袭性真菌感染。抗真菌药物的开发是困难的，因为 真菌和人体细胞，这导致许多破坏或杀死真菌的化合物具有不可接受的毒性。 开发人类细胞中不存在靶点的抗真菌药物将绕过这一困难。 提高抗真菌药物的效力也可能带来更好的结果。一个增加的范例 抗菌效力是复方新诺明的重要组合抗生素，其两组分具有靶向性 四氢叶酸生物合成的连续步骤。 这项提议的目标是找到可以开发成两种特定抑制剂的化合物。 真菌特有的细胞过程，它们的结合可能会产生一种更有效的抗真菌药物。 两种在人类中根本不同或不存在的真菌细胞突起是磷酸盐 动态平衡和细胞壁的构建。我们此前发现，主要的白色念珠菌具有高亲和力 磷酸转运蛋白Pho84是正常营养(雷帕霉素的靶标)信号所必需的，细胞壁 抗应激和氧化应激，菌丝生长和毒力。因为人类管理着他们的 磷酸盐平衡与真菌完全不同，阻断Pho84不会对人类产生影响 细胞功能。Pho84在整个真菌王国中高度保守，包括在新出现的病原体中。 就像卡迪达·奥里斯。缺乏Pho84的细胞含有浓度降低的核苷酸，其 生产需要充足的细胞内磷酸盐供应，及其下游代谢物， 核糖核酸。核苷酸糖是主要细胞壁聚合物生物合成的前体。我们 建议利用这一缺陷，通过以下方式依次扰乱细胞壁生物合成的主要步骤 将Pho84的抑制与葡聚糖生物合成的抑制相结合。为此，我们建立了一部小说 高通量检测系统，以检测这些真菌靶标的特定抑制剂。我们将优先处理HIT 根据化合物在毒性相关或必要的细胞过程中的生物效应，以及 根据它们的化学特性。这项工作将为逐步应用的范例奠定基础。 对抗真菌药物开发的关键生物合成过程的抑制。这项提议的目的是 选择符合定义的生物和药物化学标准的热门屏幕进行进一步开发。