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: 10165488
• 负责人: JULIA R KOEHLER
• 金额: $ 47.38万
• 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 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10165488
• 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; Centers for Disease Control and Prevention (U.S.); 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; Human; Hypersensitivity; Immunocompromised Host; Individual; Infection; Inorganic Phosphate Transporter; Lead; Libraries; Link; Micafungin; Mucorales; Mycoses; Nucleotides; Nutritional; Organelles; Outcome; Oxidative Stress; Patients; Pharmaceutical Chemistry; Pharmaceutical Preparations; Pharmacology; 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; base; chemical genetics; clinical care; design; drug development; drug discovery; emerging pathogen; experience; fitness; fungus; glucan synthase; high throughput screening; inhibitor/antagonist; inorganic phosphate; metabolomics; microbial; novel; novel therapeutics; optimal treatments; pathogenic fungus; 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.

项目概要/摘要 白色念珠菌是美国最常见的引起侵袭性疾病的分离真菌。 这些感染是严重疾病的可怕并发症，尤其是在住院或住院期间 免疫功能低下的患者。白色念珠菌感染难以根除，且仍处于估计状态 导致 20% 受影响患者死亡。目前只有3类抗真菌药物可用 治疗侵袭性真菌感染。由于两者的相似性，抗真菌药物的开发很困难 真菌和人类细胞，这导致许多损害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可以解决这一难题。 增强抗真菌药物的效力也可能带来更好的结果。增加的范例 抗菌效力是重要的复合抗生素复方新诺明，其两种成分针对 四氢叶酸生物合成的连续步骤。 该提案的目标是找到可以开发成两种药物特异性抑制剂的化合物 真菌特有的细胞过程，它们的结合可以产生更有效的抗真菌剂。 磷酸盐是两种在人类中根本不同或不存在的真菌细胞过程 体内平衡和细胞壁构建。我们之前发现主要的白色念珠菌具有高亲和力 磷酸盐转运蛋白 Pho84 是正常营养（雷帕霉素靶标-）信号传导、细胞壁所必需的 应激和氧化应激抗性、菌丝生长和毒力。由于人类管理自己的 磷酸盐平衡与真菌完全不同，阻断 Pho84 预计不会影响人类 细胞功能。 Pho84 在整个真菌界中高度保守，包括在新兴病原体中 如耳念珠菌。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， 核苷酸糖。核苷酸糖是主要细胞壁聚合物生物合成的前体。我们 提议利用这一缺陷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，我们创作了一部小说 高通量检测系统可检测这些真菌靶点的特异性抑制剂。我们将优先打击 根据其在毒力相关或必需的细胞过程中的生物效应的化合物，以及 根据其化学特性。这项工作将为应用逐步范式奠定基础 抑制抗真菌药物开发的关键生物合成过程。该提案旨在 选择符合定义的生物和药物化学标准的屏幕点击以进行进一步开发。